AREA FORECAST DISCUSSION...UPDATED FOR AVIATION DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 1225 AM CST MON JAN 15 2007 .AVIATION... THE COLD AIR WILL MAKE ITS WAY INTO THE STATE FROM THE NORTHWEST TONIGHT. A SURFACE LOW TOOK SHAPE OVER NORTHERN ARKANSAS...AND IT HAS BEEN GAINING STRENGTH AND PULLING THE FRONT INTO THE STATE. RADAR STILL HAS A FULL SCOPE. SOON A WINTRY MIX WILL BE AFFECTING THE NORTHERN TERMINALS...AND ATTEMPTED TO REFLECT THAT FOR HARRISON AND MOUNTAIN HOME. NORTHWEST WINDS SHOULD START TO CEILINGS AND TO IMPROVE VISIBILITIES WHERE SMALL TO NO TEMPERATURE DEW POINT SPREADS WERE PRODUCING VSBYS AT OR BELOW 3 MI. DRIER AIR WILL MOVE IN FOR MONDAY...BUT TEMPERATURES WILL BE PLUMMETING. 32 && .PREV DISCUSSION.../ISSUED 949 PM CST SUN JAN 14 2007/ UPDATE... EASTERN PART OF THE FRONTAL BOUNDARY HAS BEEN DISPLACED WESTWARD AS EVIDENCED BY RISING TEMPERATURES AT BOTH NEWPORT AND BATESVILLE. LATEST SURFACE ANALYSIS NOW PLACES THE BOUNDARY ROUGHLY ALONG AN KELD TO KLIT TO KRAV LINE. DEW POINTS HAVE ALSO SURGED OVER THIS PART OF THE STATE. WEAK SURFACE REFLECTION FORMED ON THE FRONT EARLIER THIS EVENING AND IS NOW LOCATED OVER FAR NORTHERN SHARP COUNTY. LOW TAPPED INTO THIS MOISTURE AND THE RESULT WAS A RETURN TO HEAVY RAIN OVER THE NORTHEAST PART OF THE FORECAST AREA AND ADDITIONAL FLASH FLOOD WARNINGS. LOCALLY RUN WRF10KM SHOWS THE POSITION OF THE WARM/MOIST SURGE EXCEPTIONALLY WELL. STILL ONE MORE WAVE TO KICK OUT OF CENTRAL TEXAS THIS EVENING WHICH SHOULD KEEP THE RAIN GOING OVER THE CENTRAL AND SOUTH AND WILL LEAVE CURRENT FLOOD WATCH AS IS. STILL EXPECTING FRONT TO SLIDE BACK TO THE SOUTH OVERNIGHT AS WEAK SURFACE LOW PULLS TO THE NORTHEAST AND COLDER AIR BEGINS TO SURGE BACK IN. LATEST RUC13 AND LOCALLY RUN WRF10KM BOTH SHOW THIS PROGRESSION AND EXPECT THE BOUNDARY TO BE BACK OVER THE SOUTH BY MORNING. FARTHER NORTHWEST...IT WILL BE TURNING COLDER...WITH RAIN CHANGING TO LIGHT FREEZING RAIN. IN GENERAL...ICING AMOUNTS WILL REMAIN UNDER WARNING CRITERIA...AND WENT WITH A FREEZING RAIN ADVISORY FOR AREAS NORTH OF MENA TO DANVILLE TO CLINTON TO SALEM. BASED ON CURRENT TEMPERATURE TREND AND AVAILABLE MOISTURE WHEN THE COLDER AIR ARRIVES...ANY FREEZING PRECIPITATION WILL BE CONFINED TO JUST A FEW HOURS BEFORE SUNRISE. MAJORITY OF THE FORECAST LOOKS GOOD BUT SOME SERIOUS TWEAKING WAS DONE TO TEMPS...DEW POINTS AND WINDS BASED ON CURRENT TRENDS. UPDATED PRODUCTS OUT SHORTLY. && .LZK WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 AM MONDAY FOR ARZ003-ARZ004- ARZ005-ARZ006-ARZ012-ARZ013-ARZ014-ARZ015-ARZ021-ARZ022-ARZ023- ARZ030-ARZ037-ARZ038-ARZ040-ARZ041. FLASH FLOOD WATCH UNTIL 6 AM MONDAY FOR ARZ016-ARZ024-ARZ025- ARZ031-ARZ032-ARZ033-ARZ034-ARZ039-ARZ042-ARZ043-ARZ044-ARZ045- ARZ046-ARZ047-ARZ052-ARZ053-ARZ054-ARZ055-ARZ056-ARZ057-ARZ062- ARZ063-ARZ064-ARZ065-ARZ066-ARZ067-ARZ068-ARZ069. && $$ ar AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LITTLE ROCK AR 949 PM CST SUN JAN 14 2007 .UPDATE... EASTERN PART OF THE FRONTAL BOUNDARY HAS BEEN DISPLACED WESTWARD AS EVIDENCED BY RISING TEMPERATURES AT BOTH NEWPORT AND BATESVILLE. LATEST SURFACE ANALYSIS NOW PLACES THE BOUNDARY ROUGHLY ALONG AN KELD TO KLIT TO KRAV LINE. DEW POINTS HAVE ALSO SURGED OVER THIS PART OF THE STATE. WEAK SURFACE REFLECTION FORMED ON THE FRONT EARLIER THIS EVENING AND IS NOW LOCATED OVER FAR NORTHERN SHARP COUNTY. LOW TAPPED INTO THIS MOISTURE AND THE RESULT WAS A RETURN TO HEAVY RAIN OVER THE NORTHEAST PART OF THE FORECAST AREA AND ADDITIONAL FLASH FLOOD WARNINGS. LOCALLY RUN WRF10KM SHOWS THE POSITION OF THE WARM/MOIST SURGE EXCEPTIONALLY WELL. STILL ONE MORE WAVE TO KICK OUT OF CENTRAL TEXAS THIS EVENING WHICH SHOULD KEEP THE RAIN GOING OVER THE CENTRAL AND SOUTH AND WILL LEAVE CURRENT FLOOD WATCH AS IS. STILL EXPECTING FRONT TO SLIDE BACK TO THE SOUTH OVERNIGHT AS WEAK SURFACE LOW PULLS TO THE NORTHEAST AND COLDER AIR BEGINS TO SURGE BACK IN. LATEST RUC13 AND LOCALLY RUN WRF10KM BOTH SHOW THIS PROGRESSION AND EXPECT THE BOUNDARY TO BE BACK OVER THE SOUTH BY MORNING. FARTHER NORTHWEST...IT WILL BE TURNING COLDER...WITH RAIN CHANGING TO LIGHT FREEZING RAIN. IN GENERAL...ICING AMOUNTS WILL REMAIN UNDER WARNING CRITERIA...AND WENT WITH A FREEZING RAIN ADVISORY FOR AREAS NORTH OF MENA TO DANVILLE TO CLINTON TO SALEM. BASED ON CURRENT TEMPERATURE TREND AND AVAILABLE MOISTURE WHEN THE COLDER AIR ARRIVES...ANY FREEZING PRECIPITATION WILL BE CONFINED TO JUST A FEW HOURS BEFORE SUNRISE. MAJORITY OF THE FORECAST LOOKS GOOD BUT SOME SERIOUS TWEAKING WAS DONE TO TEMPS...DEW POINTS AND WINDS BASED ON CURRENT TRENDS. UPDATED PRODUCTS OUT SHORTLY. && .PREV DISCUSSION.../ISSUED 543 PM CST SUN JAN 14 2007/ AVIATION... THE COLD AIR WILL MAKE ITS WAY INTO THE STATE OVERNIGHT AT LAST. THIS WILL BRING A CHANCE TO GET SOME FREEZING RAIN OVER OUR NORTHWEST SECTIONS DURING THE NIGHT. KHRO STILL HAS AN EAST WIND WITH TEMPS IN THE UPPER 30S...SO ATTEMPTED TO TIME THE EASTWARD MOVEMENT OF THE SURFACE BOUNDARY RUNNING NORTH TO SOUTH OVER EXTREME WESTERN ARKANSAS. PRECIPITATION WILL BE ENDING FROM NORTHWEST TO SOUTHEAST AS MUCH LOWER TEMPS AND DEW POINTS INVADE FROM THE WEST OR NORTHWEST. PREV DISCUSSION.../ISSUED 347 PM CST SUN JAN 14 2007/ SHORT TERM...TONIGHT THROUGH MONDAY NIGHT LATEST STORM WILL START WINDING DOWN TONIGHT/MONDAY...WITH COLDER AIR TO FOLLOW. SYSTEM WILL ARRIVE FROM THE SOUTHERN PLAINS...WITH ONE MORE ROUND OF PRECIPITATION. WILL BE WIDESPREAD RAIN THIS EVENING...AND COULD BE HEAVY AT TIMES IN THE SOUTHEAST HALF OF THE STATE NEAR A STALLED FRONT. KEPT A FLASH FLOOD WATCH GOING OVERNIGHT ACROSS SOUTHERN/EASTERN ARKANSAS. FARTHER NORTHWEST...WILL TURN COLDER...WITH RAIN CHANGING TO LIGHT FREEZING RAIN. IN GENERAL...ICING AMOUNTS WILL REMAIN UNDER WARNING CRITERIA...AND WENT WITH A FREEZING RAIN ADVISORY. FRONT WILL HEAD TO THE SOUTHEAST ON MONDAY...WITH COLDER AIR CONTINUING TO SPREAD THROUGH THE REGION. HAVE FALLING TEMPERATURES IN MOST AREAS. PRECIPITATION WILL END PRETTY QUICKLY ACROSS THE NORTH/WEST...WITH RAIN CONTINUING SOUTH/EAST. RAIN SHOULD END BY EVENING AS MOISTURE GETS SHUNTED TO THE SOUTHEAST BY ARCTIC HIGH PRESSURE IN THE PLAINS. SHORT TERM WILL END WILL THE SKY CLEARING...AND COLD/DRY WEATHER MONDAY NIGHT. (46) LONG TERM...TUESDAY THROUGH SUNDAY ARCTIC HIGH PRESSURE WILL BE MOVING SOUTH TUESDAY...BRINGING DRY WEATHER AND COOLER TEMPS. THIS FEATURE WILL REMAIN IN PLACE THROUGH THURSDAY. SIGNIFICANT MODEL DIFFERENCES ARE NOTED IN THE LONG TERM FOR THURSDAY NIGHT AND BEYOND. CONTINUED TREND OF PREVIOUS FORECAST WITH MENTION OF PRECIP ACROSS THE SOUTH FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. GFS HAS ANOTHER SYSTEM MOVING IN FROM THE SOUTHWEST SATURDAY WITH ANOTHER POTENTIAL FOR WINTER PRECIP. HAVE HELD OFF ON INTRODUCING PRECIP YET...DUE TO MODEL INCONSISTENCIES...BUT WILL CONTINUE TO MONITOR FOR FUTURE FORECASTS. (58) && .PRELIMINARY POINT TEMPS/POPS... LITTLE ROCK AR 38 40 23 36 / 90 50 10 10 HARRISON AR 26 28 14 29 / 90 10 0 0 HOT SPRINGS AR 35 38 22 35 / 90 50 10 10 PINE BLUFF AR 41 42 26 38 / 90 70 10 10 MOUNTAIN HOME AR 29 31 15 31 / 90 10 0 0 MONTICELLO AR 43 44 29 39 / 90 70 10 10 SEARCY AR 37 39 22 36 / 90 50 10 10 MOUNT IDA AR 33 36 20 34 / 90 30 10 10 RUSSELLVILLE AR 33 36 17 32 / 90 30 10 10 && .LZK WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 AM MONDAY FOR ARZ003-ARZ004- ARZ005-ARZ006-ARZ012-ARZ013-ARZ014-ARZ015-ARZ021-ARZ022-ARZ023- ARZ030-ARZ037-ARZ038-ARZ040-ARZ041. FLASH FLOOD WATCH UNTIL 6 AM MONDAY FOR ARZ016-ARZ024-ARZ025- ARZ031-ARZ032-ARZ033-ARZ034-ARZ039-ARZ042-ARZ043-ARZ044-ARZ045- ARZ046-ARZ047-ARZ052-ARZ053-ARZ054-ARZ055-ARZ056-ARZ057-ARZ062- ARZ063-ARZ064-ARZ065-ARZ066-ARZ067-ARZ068-ARZ069. && $$ 56 ar AREA FORECAST DISCUSSION...UPDATED FOR AVIATION DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 1123 PM CST SAT JAN 13 2007 .AVIATION... WATER VAPOR IMAGES SHOW THE BACK EDGE OF THE RAIN PRODUCING CLOUDS ACROSS THE FORECAST AREA. RADAR ECHOES HAVE DECREASED CONSIDERABLY OVER THE NORTHWEST SECTIONS IN GOOD CORRELATION TO THE WATER VAPOR PICTURES. LOW CLOUDS WILL LINGER BEHIND THE PRECIPITATION..AND COOLING WILL BRING DOWN CEILINGS AND VISIBILITIES. RAIN WILL CONTINUE PUSHING EAST AS THE SURFACE BOUNDARY SAGS EASTWARD. THE FRONT STRETCHED FROM NEAR MEMPHIS TO NORTHEAST OF TEXARKANA TO THE SHREVEPORT AREA. ELEVATED CONVECTION HAS DECREASED SIGNIFICANTLY... SO WILL LEAVE OUT ALL MENTION OF LIGHTNING AND THUNDER. && .PREV DISCUSSION.../ISSUED 930 PM CST SAT JAN 13 2007/ UPDATE... WIDESPREAD FLASH FLOODING ACROSS THE FORECAST AREA THIS EVENING AS MODERATE TO HEAVY RAINS CONTINUE TO FALL. LATEST SURFACE ANALYSIS PLACES SURFACE BOUNDARY FROM NEAR TEXARKANAA TO SOUTH OF PINE BLUFF TO NEAR HELENA AND HAS MOVED VERY LITTLE OVER THE PAST SEVERAL HOURS. FRONT CONTINUES TO ACT AS LIFTING MECHANISMS AIDED BY SEVERAL WEAK UPPER LEVEL DISTURBANCES KICKING OUT OF THE STRONG WESTERN US TROF. WITH FRONT NOT EXPECTED TO MOVE MUCH TONIGHT... PERIODS OF RAIN WILL CONTINUE AND ADDITIONAL FLASH FLOODING IS LIKELY. LATEST BUFKIT AND RUC DATA STILL KEEPING TEMPERATURES JUST WARM ENOUGH ACROSS THE NORTHWEST ZONES FOR JUST A COLD RAIN BUT A BRIEF CHANGE OVER TO WINTER PRECIP NEAR SUNRISE NOT OUT OF THE QUESTION. WATER CONTINUES TO CAUSE PROBLEMS ON AREA RIVERS AS WELL AND ARE ADDRESSED IN VARIOUS RIVER PRODUCTS. RAIN EXPECTED TO CONTINUE THROUGH SUNDAY UNTIL MAIN SYSTEM IN THE ROCKIES IS KICKED OUT AND THE FRONT IS FINALLY FORCED THROUGH THE STATE AND THEN THE COLDER AIR IS FORECAST TO SWEEP THROUGH. NOT TOO MANY CHANGES NEEDED TO THE GOING FORECAST OTHER THAN TO TWEAK THE GRIDS/ZONES FOR CURRENT TRENDS AND CONDITIONS. UPDATES OUT SHORTLY. PREV DISCUSSION.../ISSUED 551 PM CST SAT JAN 13 2007/ AVIATION... SURFACE BOUNDARY IS CROSSING THE STATE FROM NORTHEAST TO SOUTHWEST. THE NORTHWEST SECTION IS RECEIVING STEADY RAINS WHILE THE SOUTHEAST IS MORE UNSTABLE AND IT IS RECEIVING RAIN WITH EMBEDDED THUNDERSTORMS. THE SURFACE PATTERN WILL BE SLOW CHANGING SO KEPT TERMINALS IN A RATHER PESSIMISTIC FORECAST AS FAR AND CEILINGS AND VISIBILITIES GO. PREV DISCUSSION.../ISSUED 457 PM CST SAT JAN 13 2007/ SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT HEAVY RAIN AFFECTED NORTHERN/CENTRAL ARKANSAS THIS MORNING/EARLY THIS AFTERNOON...WITH TWO TO THREE INCH AMOUNTS COMMON. RAIN FOCUSED ALONG AND NORTH OF A STALLED FRONT IN SOUTHERN SECTIONS OF THE STATE. ANOTHER ROUND OF HEAVY RAIN WILL BREAK OUT TONIGHT...WITH AXIS FROM DEQUEEN TO CONWAY AND JONESBORO. ANOTHER TWO TO FOUR INCHES OF RAIN COULD OCCUR...WITH FLASH FLOODING LIKELY. STILL ANOTHER ROUND OF RAIN EXPECTED ON SUNDAY AS STORM SYSTEM TO THE WEST ARRIVES. ONE TO TWO INCHES OF RAIN POSSIBLE. CONTINUED FLASH FLOOD WATCH THROUGH SUNDAY IN NORTHERN/CENTRAL ARKANSAS...OR IN AREAS NORTH OF ARKADELPHIA...PINE BLUFF AND BRINKLEY. EXCESS WATER WILL EVENTUALLY MAKE ITS WAY INTO AREA RIVERS...WITH FLOODING ADDRESSED IN RIVER FORECASTS. OTHER ASPECT OF THIS EVENT WILL BE WINTER WEATHER. COULD BE A BRIEF PERIOD OF FREEZING RAIN IN BOONE/NEWTON/NORTHERN MARION COUNTIES OVERNIGHT AND INTO SUNDAY MORNING AS TEMPERATURES TEETER AROUND 32 DEGREES. ANY ICING WILL NOT AMOUNT TO MUCH...AND HAVE NO HEADLINES IN THESE AREAS. SUNDAY NIGHT/MONDAY...FRONT WILL MOVE TO THE SOUTH...AND MOISTURE WILL FOLLOW. HOWEVER...SO WILL COLD AIR TO THE NORTHWEST. APPEARS THAT COLD AIR WILL CATCH UP WITH THE MOISTURE...WITH SOME FREEZING RAIN/SLEET MAINLY NORTH AND WEST OF LITTLE ROCK. AMOUNTS LOOK LIKE THEY WILL REMAIN BELOW WARNING CRITERIA...BUT ADVISORIES MAY BE REQUIRED. MONDAY NIGHT/TUESDAY...MOISTURE WILL FINALLY EXIT TO THE SOUTH...WITH DRY AND COLD CONDITIONS TO FINISH THE SHORT TERM. (46) LONG TERM...WEDNESDAY THROUGH SATURDAY DRIER AND COLDER AIRMASS WL BE BLDG INTO THE FA AT THE START OF THE PD THANKS TO ARCTIC HIGH PRES. THE CENTER OF THE HIGH WL SETTLE OVR AR BY MIDWEEK AND THEN BEGIN SHIFTING OFF THE E. TEMPS WL SHOW A GRADUAL MODERATING TREND THRU THE PD. SUBTROPICAL JET WILL BRING MOISTURE ALONG THE GULF COAST...WITH SOME OF THIS MOISTURE AFFECTING CENTRAL/SOUTHERN ARKANSAS MAINLY THURSDAY THROUGH SATURDAY. FOR NOW...HAVE SLIGHT CHANCES FOR RAIN IN THESE AREAS...BUT MAY NEED TO INCREASE POPS IN LATER FORECASTS. (58) && .LZK WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 6 PM SUNDAY FOR ARZ003-ARZ004-ARZ005- ARZ006-ARZ007-ARZ012-ARZ013-ARZ014-ARZ015-ARZ016-ARZ021-ARZ022- ARZ023-ARZ024-ARZ025-ARZ030-ARZ031-ARZ032-ARZ033-ARZ034-ARZ037- ARZ038-ARZ039-ARZ040-ARZ041-ARZ042-ARZ043-ARZ044-ARZ045-ARZ046- ARZ052-ARZ053-ARZ054. && $$ AVIATION...32 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 346 AM MST MON JAN 15 2007 .SHORT TERM... (TODAY AND TONIGHT) ...BITTER COLD TEMPERATURES EARLY THIS MORNING AND AGAIN TONIGHT... ...WIND CHILL ADVISORY ACROSS EL PASO COUNTY...SOUTHERN FOOTHILLS INTO THE SOUTHEAST COLORADO PLAINS UNTIL 10 AM MST THIS MORNING... CURRENTLY...NEARLY WIDESPREAD SUB-ZERO TEMPERATURES COVERED MUCH OF THE FORECAST AREA EARLY THIS MORNING. 10 BELOW TO 15 BELOW ZERO ALREADY REPORTED AROUND LEADVILLE...SAN LUIS VALLEY FLOOR CENTER... AND PUEBLO. SURFACE WINDS HAVE BEEN RELATIVELY LIGHT IN THE HIGH COUNTY AND I-25 CORRIDOR...EXCEPT FOR SOME ENHANCED DRAINAGE WINDS...UP TO 7KTS...ACROSS THE SOUTHERN FOOTHILLS/TRINIDAD AND THE SOUTHERN PALMER DIVIDE/COLORADO SPRINGS. MORE SYNOPTIC SCALE DRIVEN WINDS WERE ACROSS THE FAR SOUTHEAST CO PLAINS WHERE WINDS ARE STILL BLOWING AROUND 11KTS AT LA JUNTA...LAMAR... SPRINGFIELD...ETC. WIND CHILL VALUES OF 15 TO 25 BELOW HAVE BEEN OCCURRING ACROSS THE SOUTHEAST COLORADO PLAINS AND EL PASO COUNTY SINCE MIDNIGHT...AND WILL LIKELY CONTINUE THIS MORNING. LONGWAVE TROUGH REMAINS OVER THE CENTRAL ROCKIES AS ANOTHER UPPER LEVEL JET STREAM AND ASSOCIATED SHORTWAVE TROUGH MOVES OUT OF WY PER WATER VAPOR AND RUC MODEL UPPER AIR ANALYSES. NOT A LOT OF QUALITY MOISTURE ASSOCIATED WITH THIS WEATHER FEATURE...IN FACT...IT IS DIFFICULT TO DISCERN CLOUDS ON THE IR SATELLITE IMAGERY GIVEN ALL THE STATIONARY "COLD POCKET" TEMPERATURES ON THE SATELLITE DATA. FOG SATELLITE IMAGERY REVEALS THE CLOUDS A LITTLE BETTER. TODAY...BITTER COLD TEMPERATURES WILL START THE DAY. PLAN TO GO WITH A WIND CHILL ADVISORY FOR ZONES COZ084-085-088-089-093>099 FOR VALUES 14 BELOW TO 25 BELOW ZERO AND WINDS UP TO 10 MPH UNTIL 10 AM MST THIS MORNING. FOR THE REMAINDER OF SOUTHEAST AND SOUTH CENTRAL CO...SUB-ZERO TEMPERATURES WILL BE IN PLACE WITH LITTLE OR NO WIND...JUST BITTERLY COLD. MIGHT SEE SOME PATCHY FREEZING FOG IN THE LOW LYING AREAS LIKE THE LOWER AR RIVER AND SAN LUIS VALLEY. SHOULD SEE A MIX OF CLOUDS AND SUN TODAY... LEANING MORE TOWARDS SUN. BIG CHALLENGE WITH ARCTIC AIR MASS IN PLACE...SNOW COVER...TERRAIN...AND VERY LITTLE WIND POTENTIAL FOR MIXING WILL BE MAXIMUM TEMPERATURES. MOS GUIDANCE IS PROBABLY TOO WARM FOR MANY OF THE LOWER ELEVATION POINTS...SO WILL CONTINUE TO UNDERCUT. TONIGHT...ANOTHER GOOD RADIATIONAL COOLING NIGHT. TOUGH TO SEE IF THE ARCTIC AIR MASS WILL BEGIN TO RECEDE ACROSS EASTERN CO AS WESTERLY SFC-PBL WINDS DEVELOP...BUT NOT ALL THAT SIGNIFICANT. AREAS HAVING TRAPPED ARCTIC AIR LIKE THE SAN LUIS...UPPER AR RIVER...AND WET MOUNTAIN...AND RIO GRANDE VALLEYS WILL LIKELY SEE SUB-ZERO TEMPERATURES AGAIN...10 BELOW TO 25 BELOW ZERO. WILL COUNT ON THE LOWER AR RIVER VALLEY TO MAINTAIN ITS ARCTIC AIR MASS. RECORD LOW TEMPERATURES FOR 16 JAN ARE...COLORADO SPRINGS -6/1987... PUEBLO -14F/1987...AND ALAMOSA -27F/1984. METZE .LONG TERM... (TUESDAY THROUGH SUNDAY) TEMPS TO REMAIN COLD FOR TUESDAY...THEN WARM UP EXPECTED THROUGH MID-LATE WEEK WITH NEXT SIGNIFICANT SYSTEM APPEARING TO HOLD OF UNTIL NEXT WEEKEND. TEMPS ON TUESDAY WILL BE THE MAIN CHALLENGE IN THE NEARER TERMS OF THE EXTENDED. WEAKENING UPPER LOW REMAINS OFF TO THE SOUTHWEST THIS DAY WITH VERY LITTLE MOISTURE ASSOCIATED WITH IT. THUS REGION SHOULD BE UNDER MOSTLY SUNNY SKIES. ARCTIC AIR MASS BEGINS TO RETREAT TO THE EAST AND BOTH GFS/NAM MODERATING LOWER LVL TEMPS DURING THE DAY. HOWEVER SFC WINDS SHOULD STAY LIGHT AND WITH FRESH SNOW COVER FROM YESTERDAY`S STORM...THINK IT WILL HAVE A DIFFICULT TIME GETTING ABOVE FREEZING...ESP SAN LUIS VALLEY AND KLAA AREA. MOS GUIDANCE STILL LOOKS TOO WARM AND WILL CONTINUE TO UNDERCUT BY SEVERAL DEGREES. CLOSED LOW OVER THE SOUTHWEST OPENS UP AND LIFTS ACROSS CO TUESDAY NIGHT/EARLY WED. MOISTURE IS FAIRLY LIMITED WITH THIS SYSTEM...WITH ONLY SOME ISOLATED SNOW SHOWERS POSSIBLE FOR THE SOUTHWEST AND CENTRAL MOUNTAINS. MAIN AFFECT THIS SYSTEM WILL HAVE ON THE EAST IS TO INDUCE LEE TROFFING WHICH WILL HELP INCREASE WINDS AND BRING A WARM UP TO THE REGION AND BEGIN TO MELT SOME OF THE SNOW BY WED. WITH DRY AIR MASS OVER THE REGION...EXPECT TEMPS TO DROP QUICKLY TUES EVENING...WITH LOWS ALONG THE EASTERN SLOPES PROBABLY OCCURRING AROUND MIDNIGHT...THEN WARMING TOWARDS MORNING AS DRAINAGE WINDS INTO LEE TROF DEVELOP. ENERGY ENTERING THE PACIFIC NORTHWEST ON TUESDAY SPLITS WITH THE NORTHERN STREAM TROF MOVING ACROSS NRN CO WED NIGHT/THURS...WHILE THE SRN STREAM ENERGY CUTS OFF AND SINKS SOUTHWARD OFF THE SRN CA COAST. THIS SOLUTION HAS TRENDED TOWARDS THE 00Z ECMWF SOLUTION FROM LAST NIGHT. LATEST 00Z ECMWF FAIRLY SIMILAR TO THE LATEST GFS RUN...AND VAST MAJORITY OF THE GFS ENSEMBLE MEMBERS SUPPORT THIS TREND. THIS WOULD MEAN SYSTEM FOR THURS WILL BE MUCH LESS OF A PLAYER FOR PRECIPITATION ACROSS THE AREA...BRINGING A BRIEF SHOT OF SNOW TO THE CENTRAL MOUNTAINS WED NIGHT...AND ANOTHER SHOT OF COLD TO THE SOUTHEAST PLAINS. GIVEN SOME CONTINUITY BETWEEN MODELS...WILL ADJUST POPS ACCORDINGLY. GFS/ECMWF STALL CLOSED LOW OFF THE SRN COAST OF CA THROUGH FRIDAY BEFORE SLOWLY LIFTING IT INTO THE DESERT SOUTHWEST BY SAT AND ACROSS CO FOR SUN. TIMING OF THIS NEXT SYSTEM BEARS A HIGH DEGREE OF UNCERTAINTY THOUGH. THUS...WILL HOLD THE COURSE WITH THE CURRENT WEEKEND FORECAST AND LET DAY SHIFT FINE-TUNE. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 10 AM MST THIS MORNING FOR COZ084-085- 088-089-093>099. && $$ 17/31 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 935 PM EST MON JAN 15 2007 .SHORT TERM UPDATE /OVERNIGHT/...INITIAL COLD FRONT WAS ADVANCING THROUGH N GA/UPSTATE OF SC. SHOWERS WERE NUMEROUS ALONG/BEHIND BOUNDARY WEST OF FORECAST AREA...HOWEVER...LATEST NAM/RUC GUIDANCE CONTINUES TO INSIST THAT COVERAGE OF SHOWERS WILL DIMINISH AS THE FRONT APPROACHES DRY AIRMASS IN PLACE ACROSS SE SC/GA...AS DEPICTED BY 0Z CHS RAOB. NEVERTHELESS...CURRENT TRENDS SUGGEST THAT A FEW SHOWERS MAY PRESS INTO FAR WESTERN COUNTIES BEFORE 12Z...THUS ADDED A SLIGHT CHANCE OF SHOWERS THERE 9Z-12Z. OTHERWISE...MADE MINOR ADJUSTMENTS TO TEMPERATURES OVERNIGHT...AS TEMPS MAY BECOME STEADY OR EVEN START TO RISE AS CLOUDS/LOW LEVEL FLOW INCREASE AHEAD OF BOUNDARY AFTER MIDNIGHT. && .MARINE...S/SW WINDS HAVE PICKED UP A BIT...AVERAGING 10-15 KT AT 41004/41008/SPAG1...ACCOMPANIED BY SEAS 3-4 FT...STILL DOMINATED BY E/SE SWELL BUT FEATURING AN INCREASED CONTRIBUTION FROM WIND WAVES. AS LOW LEVEL FLOW INCREASES AHEAD OF AN APPROACHING COLD FRONT...MIXING WILL ENHANCE WINDS OVER WARMER OUTER WATERS OVERNIGHT INTO TUESDAY...WHILE SEAS WILL BUILD TO JUST BELOW SCA CRITERIA BEYOND 20 NM. WILL NEED TO MONITOR TRENDS OF WINDS/SEAS OVER THE OUTER WATERS THIS EVENING/OVERNIGHT...FOR NOW WILL ADD AN INTERIM SCEC HEADLINE TO BRIDGE DETERIORATING CONDITIONS OVERNIGHT WITH ONSET OF MORE HAZARDOUS CONDITIONS AS STRONG POST FROPA COLD ADVECTION COMMENCES TUESDAY NIGHT. OTHERWISE...NO CHANGES PLANNED TO ONGOING SCA HEADLINES FOR TUESDAY NIGHT THROUGH WEDNESDAY EVENING. LATER SHIFTS WILL NEED TO ASSESS POTENTIAL FOR UPGRADE TO GALE WARNINGS...ESPECIALLY ACROSS THE OUTER WATERS. && .AVIATION /03Z-24Z/...COLD FRONT WAS APPROACHING THE FORECAST AREA FROM THE WEST MONDAY EVENING. AHEAD OF THE FRONT...INCREASING CLOUDS AND PERSISTENT SURFACE FLOW WERE EXPECTED TO PREVENT RADIATION FOG DEVELOPMENT AT TERMINALS. FURTHER...LOW LEVEL WIND SHEAR WILL DEVELOP AT BOTH TERMINALS AFTER MIDNIGHT. MEANWHILE...AS THE FRONT DRAWS CLOSER...CIGS 4-6 KFT APPEAR MOST LIKELY DURING THE 6Z-18Z TIME FRAME...AND POTENTIAL PRECIPITATION COVERAGE ASSOCIATED WITH FROPA JUSTIFIED VICINITY SHOWERS BOTH TERMINALS 14-24Z MONDAY. WHILE UPSTREAM TRENDS AND MODEL GUIDANCE...DEPICTING SPARSE PRECIPITATION COVERAGE AS THE COLD FRONT PRESSES INTO RELATIVELY DRY AIRMASS ACROSS THE REGION...PREVENT A MORE PESSIMISTIC FORECAST...IF SHOWERS BECOME MORE NUMEROUS THAN EXPECTED BRIEF PERIODS OF MVFR OR EVEN IFR CIGS/VISIBILITIES CANNOT BE RULED OUT AFTER 14Z. INITIAL FROPA WILL PRODUCE WIND SHIFT TO THE NW AROUND 18Z. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY TUESDAY NIGHT THROUGH WEDNESDAY NIGHT FOR AMZ330. SMALL CRAFT ADVISORY TUESDAY NIGHT THROUGH THURSDAY MORNING FOR AMZ350-352-354-374. && $$ SPR ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE ID 940 PM MST SAT JAN 13 2007 .DISCUSSION...STRONG VORT MAX MOVING RAPIDLY SOUTH FROM NORTHEAST OREGON AT THIS TIME. LATEST RUC TAKES THIS FEATURE SOUTHWARD ACROSS EASTERN OREGON AND EXTREME SOUTHWEST IDAHO DURING THE NEXT FEW HOURS WITH BROKEN TO OVERCAST MID DECK. SYSTEM HAS LIMITED MOISTURE BUT HAS BEEN SQUEEZING OUT A FEW FLURRIES OVER AREAS IN EASTERN WASHINGTON AND NORTHEAST OREGON. LATEST RADAR LOOPS SHOWING BANDS OF CLOUDS MOVING OVER THE AREA AND SUSPECT THERE COULD BE SOME LIGHT SNOW SHOWER ACTIVITY AS WELL. OTHERWISE...TEMPERATURES HAVE BEEN STEADY DURING THE PAST FEW HOURS WITH THICKER CLOUD COVER OVER THE AREA. THIS COULD BE DECEIVING HOWEVER AS RAPID CLEARING IS DEVELOPING NORTH OF VORT FEATURE AND TEMPS MAY PLUMMET AGAIN AROUND DAYBREAK SUNDAY IN THE WAKE OF THIS WEAK SYSTEM. WILL STAY THE COURSE ON OVERNIGHT MINS EVEN THOUGH TEMPS ARE NOT FALLING MUCH AT THE MOMENT. REST OF FORECAST REMAINS UNCHANGED. && .PREV DISCUSSION...CLOUDS COMING IN FROM THE NORTHWEST WILL MODERATE MIN TEMPERATURES TONIGHT BUT MOST IDAHO MOUNTAIN SITES WILL STILL DROP TO ZERO TO 10 BELOW. FAIRFIELD WILL START FROM A HIGH TODAY NEAR ZERO AND WILL ALSO STAY CLEAR LONGER THIS EVENING SO MIN TEMP OF 18 BELOW HAS BEEN FORECAST THERE. VALLEY SITES WILL BE 2-4 DEGREES MILDER THAN LAST NIGHT. SHORT WAVE TROUGH FROM THE NORTHWEST WILL BRING 20-30 POP TO OUR NORTHERN AND EASTERN MOUNTAIN ZONES LATE TONIGHT AND SUNDAY MORNING...EXITING SOUTH VIA SOUTHERN SAWTOOTHS SUNDAY. CLEARING AFTER THAT AND A REINFORCEMENT OF COLD AIR BUT NOT AS COLD AS TODAY/S AIR MASS AS SOURCE REGION IS NOT AS FAR NORTH. MOSTLY CLEAR AND CONTINUED COLD MONDAY...SLIGHT MILDER IN OREGON ZONES. LIGHT WINDS THROUGH MONDAY. LONG TERM...MONDAY NIGHT THROUGH SATURDAY...MODELS IN AGREEMENT THAT UPPER LEVEL RIDGE WILL MOVE TO THE EAST OF THE FORECAST AREA BY WEDNESDAY MORNING. WHERE THE MODELS DIFFER IS IN THE STRENGTH AND TIMING OF THE NEXT UPPER LEVEL TROUGH THAT WILL BE MOVING INTO THE PACIFIC NORTHWEST. MODELS STILL HINTING AT THIS TROUGH SPLITTING AND THAT WOULD MEAN DRIER CONDITIONS FOR THE FORECAST AREA FOR TUESDAY THROUGH THURSDAY. WILL LEAN TOWARDS THE SPLIT FOR MAINLY DRY CONDITIONS FOR MONDAY NIGHT THROUGH THURSDAY. FOR FRIDAY AND SATURDAY NO REAL RUN TO RUN CONSISTENCY WITH THE PATTERN SO WILL KEEP POPS AS IS. TEMPERATURES THROUGH THE EXTENDED PERIOD WILL BE A FEW DEGREES BELOW NORMAL AND SLOWLY WARM TO NORMAL BY SATURDAY. && AVIATION...VFR CONDITIONS MOST AREAS FOR THE REST OF TONIGHT UNDER MID-LEVEL CEILINGS. ISOLATED IFR VISIBILITIES IN SNOW SHOWERS OVER WEST CENTRAL AND BOISE MOUNTAINS THROUGH 12Z SUNDAY MORNING AND DEVELOPING OVER HIGHER TERRAIN ALONG ID/NV BORDER AFTER 12Z SUNDAY MORNING. MID-LEVEL CEILINGS WILL REMAIN BETWEEN 10-12K FEET MSL. CEILINGS WILL BREAK OUT LATE SUNDAY MORNING FROM NORTH TO SOUTH. DUE TO CLOUDS...NOT EXPECTING ANY FOG DEVELOPMENT IN VALLEYS. LIGHT NORTHERLY WINDS ALOFT THROUGH 20K MSL. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...NONE. OR...NONE. && $$ DISCUSSION...GS PREV DISCUSSION...LC LONG TERM....JA/DD AVIATION.....DG id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 907 PM CST SUN JAN 14 2007 .UPDATE... MAIN CONCERNS ARE PRECIP TYPE AND AMOUNTS OF ICE OR SNOW ACCUM THE REST OF THE NIGHT AND TOMORROW MORNING. THE BACK EDGE OF THE MAIN AREA RAIN AND FREEZING RAIN SEEMS TO BE APPROACHING OUR SW CWA SOON. IR SATELLITE IMAGES SHOW BANDED WAVES HELPING TO GENERATE ENHANCE PRECIP ACROSS EASTERN MISSOURI AND WEST CENTRAL ILLINOIS ATTM. THIS PUSH IS MATCHING UP WELL WITH THE BACK EDGE OF THE MAIN AREA OF RAIN. FEEL THERE WILL BE A BIG DROP OFF IN MEASURABLE RAIN AND FREEZING RAIN AFTER MIDNIGHT IN MUCH OF CENTRAL ILLINOIS. THERE DOES APPEAR TO BE ADDITIONAL MOISTURE AND COLD CLOUD TOPS BEHIND THIS RAIN BAND. THE INVERTED TROUGH HAS YET TO ENTER INTO ILLINOIS AS WELL...SO LIGHT RAIN...FREEZING RAIN...OR SNOW SHOULD CONTINUE INTO MONDAY MORNING...BUT AT MUCH SLOWER RATES THAN THIS EVENING. WORKING ON UPDATING THE GRIDS FOR PLACEMENT OF THE MOST FREEZING RAIN AND SNOW. FREEZING LINE SEEMED TO BE PERSISTING MUCH FARTHER NORTHWEST THAN PREVIOUSLY EXPECTED. I SEE THE BLOOMINGTON HAS JUST NOW FINALLY REPORTED FREEZING RAIN...BUT LINCOLN REMAINS 34 AND SPRINGFIELD IS 35. THAT CORRIDOR OF CENTRAL ILLINOIS IS A TOUGH CALL ON WHEN THEY WILL GO BELOW FREEZING. RUC METEOGRAMS ARE KEEPING SPI ABOVE FREEZING THROUGH AT LEAST 12Z...SO I AM HAVING TROUBLE FORECASTING ICE ACCUM THERE. WILL GO ON PREMISE THAT ELEVATED TREE LIMBS AND POWER LINES WILL SEE FREEZING AND ICE ACCUM...AND THAT IS WHERE THE PUBLIC IMPACT WILL BE GREATEST...IF THE BRANCHES BREAK AND POWER LINES COME DOWN. IN KNOX...STARK AND NORTHERN FULTON COUNTIES...TEMPS HAVE REMAINED BELOW FREEZING DURING THE RAIN THIS EVENING...AS ICE ACCUMS ON TREES AND POWERLINES ARE NEARING A QUARTER INCH. NORTHWEST WINDS HAVE SUBSIDED TO LESS THAN 10 MPH IN MOST AREAS...BUT STILL SOME SWAYING OF THE TREES MAY CAUSE BRANCHES TO SNAP. SNOW AMOUNTS IN THAT AREA SHOULD NOT CLIMB MUCH OVER AN INCH...AS THE BULK OF THE PRECIPITATION WILL BE OVER BEFORE THE SNOW STARTS ACCUMULATING. WILL KEEP THE WINTER WEATHER ADVISORY GOING AS IS...WITH THE FREEZING RAIN THROUGH MIDNIGHT...THEN THE FREEZING DRIZZLE OR SNOW THE REST OF THE NIGHT...ESPECIALLY NORTHWEST OF THE ILLINOIS RIVER...AND LESS ICE AND SNOW BETWEEN THE ILLINOIS RIVER AND THE I-55 CORRIDOR. EAST OF I-55 WILL NOT SEE MUCH FREEZING RAIN THROUGH MIDNIGHT. PRECIP IN THAT AREA WILL CHANGE TO DRIZZLE OR SCATTERED RAIN SHOWERS AFTER MIDNIGHT UNTIL MORNING...THEN MIX WITH OR CHANGE TO SNOW DURING THE MORNING. UPDATED ZONES WILL BE OUT SHORTLY...WITH MAIN CHANGES TO THE PRECIP WORDING AND SNOW AMOUNTS /LESS SNOW/. && .PREV DISCUSSION... /ISSUED 330 PM CST SUN JAN 14 2007/ DISCUSSION... WINTER WEATHER SYSTEM IS MAIN CONCERN...WITH PCPN TYPE OVERNIGHT AS THE SYSTEM CONTINUES AS PLANNED JUST WITH LITTLE WARMER SURFACE TEMPS THAN ORIGINALLY THOUGHT. HOWEVER SFC TEMPS ARE STILL 1-2 DEGS BELOW NAM AND GFS MODEL. SO...ACTUALLY APPEARS THAT SFC TEMPS VERIFY BEST WITH EITHER NGM OR THE RUC MODELS. THEREFORE WILL FOLLOW THOSE IN THE VERY SHORT TERM AND THEN ADJUST NAM/GFS FURTHER OUT. SHORT TERM...TONIGHT THROUGH WEDNESDAY... SFC LOW SITTING IN WESTERN ARK AT 20Z AND IS SHOWING SIGNS OF DEEPENING AS SFC HEIGHT FALLS OF 4 TO 5 MB IS SEEN IN THE SFC DATA TO THE NORTH ACRS SOUTHERN MO AND INTO NERN KS. A SFC TROUGH IS ALSO EVIDENT IN THE SFC DATA FROM SOUTHERN IL INTO EASTERN IA. THEREFORE...NEUTRAL TEMP ADVECTION CAN BE EXPECTED INTO THE EARLY EVENING HOURS. THIS MEANS THAT MOST OF PCPN MOVING INTO AREA WILL START AS RAIN AND THEN CHANGE TO FREEZING RAIN...FROM WEST TO EAST...AS THE NIGHT PROGRESSES. BELIEVE AREAS ALONG AND NORTHWEST OF IL RIVER WILL QUICKLY CHANGE TO FREEZING RAIN THIS EVENING AND THEN MIX WITH SLEET BEFORE CHANGING TO SNOW BY MIDNIGHT. AREAS ALONG I-55 WILL START AS RAIN AND THEN CHANGE TO FREEZING RAIN BEFORE MIDNIGHT AND THEN MIX WITH SOME SLEET AND SNOW AFTER MIDNIGHT. AREAS TO THE EAST WILL SEE ALL RAIN UNTIL MIDNIGHT AND THEN CHANGE TO A MIX OF FREEZING RAIN AND SLEET AFTER MIDNIGHT BEFORE CHANGING TO SNOW IN THE MORNING. WITH THE LINE OF FREEZING RAIN/SLEET BETWEEN RAIN STILL BEING ALONG A BLOOMINGTON TO DECATUR TO TAYLORVILLE LINE...WILL LEAVE THE WINTER WEATHER ADVISORY AS IS...BUT JUST CHANGE THE ENDING TIME TO NOON TOMORROW. WITH SYSTEM LIFTING NORTHEAST TONIGHT AND LITTLE FURTHER NORTH THAN ORIGINALLY THOUGHT...SNOWFALL AMOUNTS WILL BE ON THE ADVISORY SIDE OR LESS IN MOST AREA. TOTAL SNOWFALL WILL BE AN INCH OR LESS ALONG I-72 CORRIDOR WITH HIGHER AMOUNTS FURTHER NORTH...REACHING TO JUST UNDER 4 INCHES IN THE FAR NORTH OF THE CWA. PIA AROUND 2 INCHES AND BLOOMINGTON AROUND 1.5 INCHES. PCPN WILL END DURING THE DAY TOMORROW WITH LITTLE IF ANY ADDITIONAL ACCUMULATION OF EITHER SNOW OR ICE. STILL AREAS IN THE SOUTHEAST COULD STILL BE WARM ENOUGH THAT THE PCPN COULD BE A MIX OF RAIN AND SNOW. AFTER THIS SYSTEM MOVES OUT...COLDER AIR WILL ADVECT INTO THE AREA...WITH THE COLDEST TEMPS IN THE NORTH WITH THE SNOW COVER. COLDEST TEMPS EXPECTED TO BE TUESDAY AND TUESDAY NIGHT AS CENTER OF THE HIGH SETTLES OVER THE AREA...CLOUDS DISAPPEAR AND WINDS BECOME LIGHT. THEN WEDNESDAY...TEMPS WILL SLOWLY CLIMB BACK TO NEAR NORMAL. LONG TERM...THURSDAY THROUGH SUNDAY... MODIFY ZONAL PATTERN WILL BECOME THE RULE DURING THE EXTENDED WITH SEVERAL MINOR WAVES FORECAST TO MOVE ACRS THE AREA. WITH LITTLE MOISTURE TO WORK WITH AND STILL SOME UNCERTAINTIES ON STRENGTH AND TIMING OF WAVES...WILL KEEP EXTENDED DRY. TEMPS THROUGH THE EXTENDED WILL REMAIN CLOSE TO NORMAL WITH A SLIGHT WARMING TREND NEXT WEEKEND. && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 12 PM CST MONDAY FOR ILZ027>031- 036>038-040>043-047>053. && $$ SHIMON/AUTEN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 330 PM CST SUN JAN 14 2007 .DISCUSSION... WINTER WEATHER SYSTEM IS MAIN CONCERN...WITH PCPN TYPE OVERNIGHT AS THE SYSTEM CONTINUES AS PLANNED JUST WITH LITTLE WARMER SURFACE TEMPS THAN ORIGINALLY THOUGHT. HOWEVER SFC TEMPS ARE STILL 1-2 DEGS BELOW NAM AND GFS MODEL. SO...ACTUALLY APPEARS THAT SFC TEMPS VERIFY BEST WITH EITHER NGM OR THE RUC MODELS. THEREFORE WILL FOLLOW THOSE IN THE VERY SHORT TERM AND THEN ADJUST NAM/GFS FURTHER OUT. SHORT TERM...TONIGHT THROUGH WEDNESDAY... SFC LOW SITTING IN WESTERN ARK AT 20Z AND IS SHOWING SIGNS OF DEEPENING AS SFC HEIGHT FALLS OF 4 TO 5 MB IS SEEN IN THE SFC DATA TO THE NORTH ACRS SOUTHERN MO AND INTO NERN KS. A SFC TROUGH IS ALSO EVIDENT IN THE SFC DATA FROM SOUTHERN IL INTO EASTERN IA. THEREFORE...NEUTRAL TEMP ADVECTION CAN BE EXPECTED INTO THE EARLY EVENING HOURS. THIS MEANS THAT MOST OF PCPN MOVING INTO AREA WILL START AS RAIN AND THEN CHANGE TO FREEZING RAIN...FROM WEST TO EAST...AS THE NIGHT PROGRESSES. BELIEVE AREAS ALONG AND NORTHWEST OF IL RIVER WILL QUICKLY CHANGE TO FREEZING RAIN THIS EVENING AND THEN MIX WITH SLEET BEFORE CHANGING TO SNOW BY MIDNIGHT. AREAS ALONG I-55 WILL START AS RAIN AND THEN CHANGE TO FREEZING RAIN BEFORE MIDNIGHT AND THEN MIX WITH SOME SLEET AND SNOW AFTER MIDNIGHT. AREAS TO THE EAST WILL SEE ALL RAIN UNTIL MIDNIGHT AND THEN CHANGE TO A MIX OF FREEZING RAIN AND SLEET AFTER MIDNIGHT BEFORE CHANGING TO SNOW IN THE MORNING. WITH THE LINE OF FREEZING RAIN/SLEET BETWEEN RAIN STILL BEING ALONG A BLOOMINGTON TO DECATUR TO TAYLORVILLE LINE...WILL LEAVE THE WINTER WEATHER ADVISORY AS IS...BUT JUST CHANGE THE ENDING TIME TO NOON TOMORROW. WITH SYSTEM LIFTING NORTHEAST TONIGHT AND LITTLE FURTHER NORTH THAN ORIGINALLY THOUGHT...SNOWFALL AMOUNTS WILL BE ON THE ADVISORY SIDE OR LESS IN MOST AREA. TOTAL SNOWFALL WILL BE AN INCH OR LESS ALONG I-72 CORRIDOR WITH HIGHER AMOUNTS FURTHER NORTH...REACHING TO JUST UNDER 4 INCHES IN THE FAR NORTH OF THE CWA. PIA AROUND 2 INCHES AND BLOOMINGTON AROUND 1.5 INCHES. PCPN WILL END DURING THE DAY TOMORROW WITH LITTLE IF ANY ADDITIONAL ACCUMULATION OF EITHER SNOW OR ICE. STILL AREAS IN THE SOUTHEAST COULD STILL BE WARM ENOUGH THAT THE PCPN COULD BE A MIX OF RAIN AND SNOW. AFTER THIS SYSTEM MOVES OUT...COLDER AIR WILL ADVECT INTO THE AREA...WITH THE COLDEST TEMPS IN THE NORTH WITH THE SNOW COVER. COLDEST TEMPS EXPECTED TO BE TUESDAY AND TUESDAY NIGHT AS CENTER OF THE HIGH SETTLES OVER THE AREA...CLOUDS DISAPPEAR AND WINDS BECOME LIGHT. THEN WEDNESDAY...TEMPS WILL SLOWLY CLIMB BACK TO NEAR NORMAL. LONG TERM...THURSDAY THROUGH SUNDAY... MODIFY ZONAL PATTERN WILL BECOME THE RULE DURING THE EXTENDED WITH SEVERAL MINOR WAVES FORECAST TO MOVE ACRS THE AREA. WITH LITTLE MOISTURE TO WORK WITH AND STILL SOME UNCERTAINTIES ON STRENGTH AND TIMING OF WAVES...WILL KEEP EXTENDED DRY. TEMPS THROUGH THE EXTENDED WILL REMAIN CLOSE TO NORMAL WITH A SLIGHT WARMING TREND NEXT WEEKEND. && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR ILZ027>031-036>038-040>043-047>053. && $$ AUTEN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 556 PM EST MON JAN 15 2007 .AVIATION... MAIN CONCERN FOR THE 00Z TAF CYCLE IS LAKE EFFECT SNOW TIMING/INTENSITY AT KSBN TERMINAL. FIRST...A GENERAL AREA OF LIGHT SNOW WILL MOVE EAST THROUGH KSBN THE FIRST HALF OF TONIGHT...AND PROBABLY REACH KFWA IN A WEAKENED STATE BY MID/LATE EVENING IN ASSOCIATION WITH APPROACH OF MID LEVEL TROUGH AXIS AND LOW LEVEL ARCTIC FRONT. SEVERAL BANDS OF LAKE EFFECT SNOW ALREADY DEVELOPING OVER THE NORTHERN HALF OF LAKE MICHIGAN SHOWN ON KGRB AND KGRR RADARS EARLY THIS EVENING. EXPECT THESE BANDS TO CONSOLIDATE INTO A SINGLE BAND LATER THIS EVENING AS LOW LEVEL CONVERGENCE INCREASES DOWN THE MAJOR AXIS OF LAKE MICHIGAN...AND THEN CURVE CYCLONICALLY INTO NW INDIANA. TIMING DIFFICULT FOR KSBN TAF AT THIS EARLY JUNCTURE AS BAND MAY OSCILLATE EAST AND WEST AND CROSS THE TERMINAL SEVERAL TIMES. BEST ESTIMATE IS HEAVIEST SNOW POTENTIAL IS LATE TONIGHT THROUGH MID MORNING TUE. LATER SHIFTS CAN ADJUST AND ADD VLIFR BASED ON RADAR TRENDS. HAVE ADDED A TEMPO MVFR GROUP AT KFWA TUE AFTERNOON AS SINGLE BAND SHIFTS EAST AND BREAKS APART INTO MULTIPLE BANDS...SOME OF WHICH MAY CLIP KFWA TERMINAL FOR A FEW HOURS. A NOTE FOR THOSE LOOKING AT MESOSCALE MODEL OUTPUT FOR THIS LAKE EFFECT SNOW EVENT...SUCH AS THE NAM-WRF...CANADIAN REGIONAL GEM...OR THE FSL RUC. WE HAVE SEEN A SYSTEMATIC BIAS OF MESOSCALE MODELS BEING TO FAR WEST WITH BAND PLACEMENT IN SINGLE BAND SITUATIONS. THE VAST MAJORITY OF THE TIME THE LAKE EFFECT SNOW BAND VERIFIES 10 TO 20 NM EAST OF THE MESOSCALE MODEL BAND LOCATION...ASSUMING THE MODEL HAS A GOOD HANDLE ON THE SYNOPTIC BACKGROUND FLOW. && .SHORT TERM... TONIGHT AND TUESDAY ...MAJOR LAKE EFFECT SNOW EVENT TONIGHT INTO TUESDAY... FORECAST CONCERN IN THE SHORT TERM REVOLVES AROUND LAKE EFFECT SNOW POTENTIAL LATER THIS EVENING THROUGH TUE AFTERNOON. FIRST...OUTSIDE OF LAKE EFFECT AREAS A BAND OF SNOW IS MOVING THROUGH THE N/NW PORTION OF THE CWA THIS AFTERNOON ALONG FIRST OF SEVERAL SECONDARY COLD FRONTS. THE TRUE ARCTIC FRONT LIES OVER SOUTHERN WISCONSIN AND CENTRAL LOWER MICHIGAN WITH REGIONAL RADARS SHOWING ANOTHER BAND OF ENHANCED SNOW ALONG AND BEHIND THIS FEATURE. ALSO A LARGE AREA OF LIGHT SNOW ASSOCIATED WITH DECAYING DEFORMATION AXIS UPSTREAM FROM NORTHERN ILLINOIS INTO LOWER MICHIGAN. GIVEN LOOK OF UPSTREAM RADARS AND EXPECTED PASSAGE OF MID LEVEL TROUGH AXIS AND ASSOCIATED LIFT... MAY SEE A GENERAL LIGHT SNOWFALL ACROSS MOST OF THE CWA TONIGHT. WILL PROBABLY END UP GOING WITH LOW LIKELY POPS AND A COATING OF ACCUMS IN MOST AREAS...EXCEPT FOR THE FAR SOUTH. NOW FOR THE LAKE EFFECT. FORECAST SURFACE PRESSURE FIELDS SHOW A CLASSIC PATTERN RECOGNITION FOR A BIG SOUTHERN LAKE MICHIGAN EVENT WITH A 1040+MB ARCTIC HIGH BUILDING SOUTH DOWN THE PLAINS. UPSTREAM RADARS SHOWING HEALTHY BANDS OF LAKE EFFECT SNOW DEVELOPING ON NORTHERLY FETCH OF LAKE SUPERIOR AND ANOTHER OFF GREEN BAY AFFECTING THE DOOR PENINSULA. LAST FEW RUNS OF THE NAM-WRF AND THE FSL EXPERIMENTAL 13KM RUC HAVE BEEN REASONABLY CONSISTENT IN DEVELOPING A WELL DEFINED SINGLE BAND TONIGHT DOWN THE LONG AXIS OF LAKE MICHIGAN. INSTABILITY IS VERY GOOD WITH LAKE INDUCED CAPES EXCEEDING 500J/KG AND EQUILIBRIUM LEVELS ABOVE 700MB. CLOUD BEARING LAYER AND ASSOCIATED MODEL INDUCED OMEGA SHOWING A NICE BULLSEYE SIGNATURE INTERSECTING THE FAVORED DENDRITIC SNOW GROWTH ZONE. MESOSCALE MODELS ALSO SUGGESTING AN UPSTREAM CONNECTION TO LAKE SUPERIOR FOR AWHILE TONIGHT...WHICH IS A CLASSIC HALLMARK OF OUR BIG EVENTS AT THE SOUTH END OF LAKE MICHIGAN. CONVERGENCE ALREADY BEGINNING TO DEVELOP DOWN THE AXIS OF THE LAKE AS NOTED IN SURFACE OBS ALONG THE E AND W SHORELINES...AND NAM-WRF STRENGTHENS LOW LEVEL CONVERGENCE FIELD AS IT ARCS CYCLONICALLY INTO NW INDIANA AND SW LOWER MICHIGAN. ALL SIGNS POINT TOWARDS THE POTENTIAL OF A MAJOR LAKE EFFECT SNOW EVENT...WHICH HAS BEEN A RARITY AROUND HERE THE PAST FEW SEASONS GIVEN THE WARM TEMPERATURES. THE FORECAST DETAILS...WILL BE UPGRADING THE LES WATCH TO A WARNING FOR BERRIEN...CASS...ST JOSEPH...AND ELKHART COUNTIES. THE REMAINDER OF THE COUNTIES IN THE WATCH WILL BE UPGRADED TO AN ADVISORY. MAY SEE A RATHER INTENSE BAND ACROSS PARTS OF LAPORTE...STARKE... MARSHALL...AND KOSCIUSKO COUNTIES...HOWEVER EXPECT THE BAND TO REMAIN TRANSIENT THROUGH THESE COUNTIES AND NOT STAY OVER ONE SPOT LONG ENOUGH TO DROP WARNING CRITERIA. IF IT BECOMES APPARENT THAT THE BAND WILL GO STATIONARY FOR SEVERAL HOURS OVER ONE OF THESE COUNTIES THAN AN UPGRADE MAY BE NEEDED. EXPECT THE MAJOR SINGLE BAND TO BREAK APART INTO MULTIPLE BANDS...WEAKEN...AND SPREAD EAST ON TUE AFTERNOON AS FLOW BACKS AND SYNOPTIC SCALE SUBSIDENCE INCREASES. STORM TOTALS OF 6 TO 12 INCHES ARE POSSIBLE IN SOME LOCATIONS IN THE WARNING COUNTIES...WITH LOCAL AMOUNTS OF OVER A FOOT POSSIBLE WHERE BANDS PERSIST THE LONGEST. && .LONG TERM... TUESDAY NIGHT THROUGH MONDAY RATHER DRAMATIC PATTN SHIFT HAS COMMENCED W/DEEP NEG HGT ANOMALY FORECAST TO DVLP ACRS ERN CANADA BY THIS WEEKEND AND OF WHICH CONSIDERING THE BACKDROP OF NAO/AO TELECONNECTIONS GOING SLIGHTLY NEGATIVE SUGGEST A CONTD INFLUX OF ARCTIC AIR INTO THE NC/NE US AND ESP SO EARLY NXT WEEK IF PROGGED CROSS POLAR FLW DVLPS AS SUGGESTED PER GFS ENSEMBLES. MAIN STORY IS ARRIVAL OF TRUE WINTERTIME AIRMASS W/TEMPS AOB NORMAL FOR A CHANGE THIS WEEK AND SNOW POTENTIAL W/SHARPENING ERN US TROUGHING AND NXT ARCTIC INTRUSION BY WEEKS END. COLDER SLANT OF 12Z GFS PREFERRED ESP IN LIGHT OF SHRT TERM LK EFFECT SNOW POTENTIAL AND SUPPRESSION OF ANY SIG SRN STREAM DVLPMNT THIS WEEK BOTH OF WHICH KEEPS SEASONABLY COLD AIR IN PLACE. DIFFS AMG MED RANGE GUIDANCE REMAIN W/DEPTH/INTENSITY OF SHARPENING NRN STREAM TROUGH FRI/SAT AND MORE IMPORTANTLY LL FLW TRAJECTORIES DOWNSTREAM OF LK MI. CURRENT GRIDS HAVE THIS IN MIND W/LOW CHC POPS FAVORED FRI-SAT AND LEFT AS IS. OTHERWISE BIGGER ISSUES CROP UP W/HANDLING OF SRN STREAM CUTOFF LATE THIS WEEKEND AND EARLY NXT WEEK W/BULK OF MED RANGE GUIDANCE SUGGESTING THIS SYS WILL KICK OUT INTO THE PLAINS LATE THIS WEEKEND AHD OF RENEWED NRN STREAM FORCED WRN TROUGH DVLPMNT...AND W/COLD AIR IN PLACE DOWNSTREAM THINGS MAY GET INTERESTING SUNDAY AND MONDAY W/AT LEAST LOW CHC POPS WARRANTED FOR MAINLY SNOW THEN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ004-INZ005. LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY FOR INZ003-INZ012. LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ014-INZ016. MI...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...HITCHCOCK LONG TERM...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 314 PM EST MON JAN 15 2007 .SHORT TERM... TONIGHT AND TUESDAY ...MAJOR LAKE EFFECT SNOW EVENT TONIGHT INTO TUESDAY... FORECAST CONCERN IN THE SHORT TERM REVOLVES AROUND LAKE EFFECT SNOW POTENTIAL LATER THIS EVENING THROUGH TUE AFTERNOON. FIRST...OUTSIDE OF LAKE EFFECT AREAS A BAND OF SNOW IS MOVING THROUGH THE N/NW PORTION OF THE CWA THIS AFTERNOON ALONG FIRST OF SEVERAL SECONDARY COLD FRONTS. THE TRUE ARCTIC FRONT LIES OVER SOUTHERN WISCONSIN AND CENTRAL LOWER MICHIGAN WITH REGIONAL RADARS SHOWING ANOTHER BAND OF ENHANCED SNOW ALONG AND BEHIND THIS FEATURE. ALSO A LARGE AREA OF LIGHT SNOW ASSOCIATED WITH DECAYING DEFORMATION AXIS UPSTREAM FROM NORTHERN ILLINOIS INTO LOWER MICHIGAN. GIVEN LOOK OF UPSTREAM RADARS AND EXPECTED PASSAGE OF MID LEVEL TROUGH AXIS AND ASSOCIATED LIFT... MAY SEE A GENERAL LIGHT SNOWFALL ACROSS MOST OF THE CWA TONIGHT. WILL PROBABLY END UP GOING WITH LOW LIKELY POPS AND A COATING OF ACCUMS IN MOST AREAS...EXCEPT FOR THE FAR SOUTH. NOW FOR THE LAKE EFFECT. FORECAST SURFACE PRESSURE FIELDS SHOW A CLASSIC PATTERN RECOGNITION FOR A BIG SOUTHERN LAKE MICHIGAN EVENT WITH A 1040+MB ARCTIC HIGH BUILDING SOUTH DOWN THE PLAINS. UPSTREAM RADARS SHOWING HEALTHY BANDS OF LAKE EFFECT SNOW DEVELOPING ON NORTHERLY FETCH OF LAKE SUPERIOR AND ANOTHER OFF GREEN BAY AFFECTING THE DOOR PENINSULA. LAST FEW RUNS OF THE NAM-WRF AND THE FSL EXPERIMENTAL 13KM RUC HAVE BEEN REASONABLY CONSISTENT IN DEVELOPING A WELL DEFINED SINGLE BAND TONIGHT DOWN THE LONG AXIS OF LAKE MICHIGAN. INSTABILITY IS VERY GOOD WITH LAKE INDUCED CAPES EXCEEDING 500J/KG AND EQUILIBRIUM LEVELS ABOVE 700MB. CLOUD BEARING LAYER AND ASSOCIATED MODEL INDUCED OMEGA SHOWING A NICE BULLSEYE SIGNATURE INTERSECTING THE FAVORED DENDRITIC SNOW GROWTH ZONE. MESOSCALE MODELS ALSO SUGGESTING AN UPSTREAM CONNECTION TO LAKE SUPERIOR FOR AWHILE TONIGHT...WHICH IS A CLASSIC HALLMARK OF OUR BIG EVENTS AT THE SOUTH END OF LAKE MICHIGAN. CONVERGENCE ALREADY BEGINNING TO DEVELOP DOWN THE AXIS OF THE LAKE AS NOTED IN SURFACE OBS ALONG THE E AND W SHORELINES...AND NAM-WRF STRENGTHENS LOW LEVEL CONVERGENCE FIELD AS IT ARCS CYCLONICALLY INTO NW INDIANA AND SW LOWER MICHIGAN. ALL SIGNS POINT TOWARDS THE POTENTIAL OF A MAJOR LAKE EFFECT SNOW EVENT...WHICH HAS BEEN A RARITY AROUND HERE THE PAST FEW SEASONS GIVEN THE WARM TEMPERATURES. THE FORECAST DETAILS...WILL BE UPGRADING THE LES WATCH TO A WARNING FOR BERRIEN...CASS...ST JOSEPH...AND ELKHART COUNTIES. THE REMAINDER OF THE COUNTIES IN THE WATCH WILL BE UPGRADED TO AN ADVISORY. MAY SEE A RATHER INTENSE BAND ACROSS PARTS OF LAPORTE...STARKE... MARSHALL...AND KOSCIUSKO COUNTIES...HOWEVER EXPECT THE BAND TO REMAIN TRANSIENT THROUGH THESE COUNTIES AND NOT STAY OVER ONE SPOT LONG ENOUGH TO DROP WARNING CRITERIA. IF IT BECOMES APPARENT THAT THE BAND WILL GO STATIONARY FOR SEVERAL HOURS OVER ONE OF THESE COUNTIES THAN AN UPGRADE MAY BE NEEDED. EXPECT THE MAJOR SINGLE BAND TO BREAK APART INTO MULTIPLE BANDS...WEAKEN...AND SPREAD EAST ON TUE AFTERNOON AS FLOW BACKS AND SYNOPTIC SCALE SUBSIDENCE INCREASES. STORM TOTALS OF 6 TO 12 INCHES ARE POSSIBLE IN SOME LOCATIONS IN THE WARNING COUNTIES...WITH LOCAL AMOUNTS OF OVER A FOOT POSSIBLE WHERE BANDS PERSIST THE LONGEST. && .LONG TERM... TUESDAY NIGHT THROUGH MONDAY RATHER DRAMATIC PATTN SHIFT HAS COMMENCED W/DEEP NEG HGT ANOMALY FORECAST TO DVLP ACRS ERN CANADA BY THIS WEEKEND AND OF WHICH CONSIDERING THE BACKDROP OF NAO/AO TELECONNECTIONS GOING SLIGHTLY NEGATIVE SUGGEST A CONTD INFLUX OF ARCTIC AIR INTO THE NC/NE US AND ESP SO EARLY NXT WEEK IF PROGGED CROSS POLAR FLW DVLPS AS SUGGESTED PER GFS ENSEMBLES. MAIN STORY IS ARRIVAL OF TRUE WINTERTIME AIRMASS W/TEMPS AOB NORMAL FOR A CHANGE THIS WEEK AND SNOW POTENTIAL W/SHARPENING ERN US TROUGHING AND NXT ARCTIC INTRUSION BY WEEKS END. COLDER SLANT OF 12Z GFS PREFERRED ESP IN LIGHT OF SHRT TERM LK EFFECT SNOW POTENTIAL AND SUPPRESSION OF ANY SIG SRN STREAM DVLPMNT THIS WEEK BOTH OF WHICH KEEPS SEASONABLY COLD AIR IN PLACE. DIFFS AMG MED RANGE GUIDANCE REMAIN W/DEPTH/INTENSITY OF SHARPENING NRN STREAM TROUGH FRI/SAT AND MORE IMPORTANTLY LL FLW TRAJECTORIES DOWNSTREAM OF LK MI. CURRENT GRIDS HAVE THIS IN MIND W/LOW CHC POPS FAVORED FRI-SAT AND LEFT AS IS. OTHERWISE BIGGER ISSUES CROP UP W/HANDLING OF SRN STREAM CUTOFF LATE THIS WEEKEND AND EARLY NXT WEEK W/BULK OF MED RANGE GUIDANCE SUGGESTING THIS SYS WILL KICK OUT INTO THE PLAINS LATE THIS WEEKEND AHD OF RENEWED NRN STREAM FORCED WRN TROUGH DVLPMNT...AND W/COLD AIR IN PLACE DOWNSTREAM THINGS MAY GET INTERESTING SUNDAY AND MONDAY W/AT LEAST LOW CHC POPS WARRANTED FOR MAINLY SNOW THEN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ004-INZ005. LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY FOR INZ003-INZ012. LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ014-INZ016. MI...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM...HITCHCOCK LONG TERM...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1119 AM EST MON JAN 15 2007 .UPDATE... ISSUED AN UPDATE TO REMOVE ALL MEASURABLE PRECIP FOR THE NEXT SEVERAL HOURS. MID LEVEL DRY SLOT HAS MOVED OVERHEAD AND ENDED RAINFALL ACROSS THE REGION. GIVEN DEEP LOW LEVEL MOISTURE FIELD AND WEAK LOW LEVEL LIFT IN PLACE...WILL MENTION PATCHY DRIZZLE THROUGH MID AFTERNOON FOR MOST AREAS...PATCHY FREEZING DRIZZLE IN AREAS WHICH REMAIN BELOW FREEZING. BY LATER THIS AFTERNOON...EXPANSIVE AREA OF LIGHT SNOW SHOWN ON UPSTREAM RADARS OVER WISCONSIN MAY REACH INTO THE NW CWA AS MID LEVEL TROUGH AXIS SHIFTS EAST AND LOW LEVEL ARCTIC COLD FRONT APPROACHES. HAVE CONTINUED WITH LIKELY POPS LATE THIS AFTERNOON OVER THE NW COUNTIES AND WORDED AS LIGHT SNOW LIKELY. OTHERWISE MAIN CONCERN IS LAKE EFFECT SNOW POTENTIAL. STILL LOOKING LIKE A SIGNIFICANT EVENT TONIGHT INTO TUE. WILL PERUSE FULL 12Z MODEL SUITE BEFORE MAKING ANY CHANGES...BUT AT EARLY GLANCE IT APPEARS WARNINGS WILL BE NEEDED FOR A PORTION OF THE WATCH AREA AS A MAJOR SINGLE BAND DEVELOPS IN RESPONSE TO CONVERGENT CYCLONIC FLOW DOWN THE MAJOR AXIS OF LAKE MICHIGAN. && .PREV DISCUSSION... AVIATION... RADAR SHOWING PCPN ENDING AT BOTH SITES. SOME LIGHT DRIZZLE OR FLURRIES POSSIBLE THIS MORNING. WRAP AROUND MOISTURE THIS AFTERNOON WITH SHORT WAVE MAY BRING SNOW SHOWERS BACK TO THE AREA WITH COLD AIR ADVECTION. BEEN A BIT MORE OPTIMISTIC WITH VIS. LAKE EFFECT SNOW SHOWERS TONIGHT...ESPECIALLY AT KSBN. DROPPED VIS TO 1SM THERE BUT LOWER RESTRICTIONS CERTAINLY POSSIBLE AND EXPECTED. WILL REFINE AS EVENT DRAWS CLOSER AND SNOW BAND BECOMES EVIDENT ON RADAR. SHORT TERM... TODAY AND TONIGHT... ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE TONIGHT AND TUESDAY... NUMEROUS ISSUES IN THE SHORT TERM BEGINNING WITH ONGOING HEADLINES AND ENDING WITH HEAVY LAKE EFFECT SNOW POTENTIAL TONIGHT INTO TUESDAY. AS WE HAVE BEEN SAYING FOR DAYS...SURFACE LOW IS TRACKING WELL NORTHWEST OF WHERE MODELS HAD BEEN INDICATING...CURRENTLY NEAR KBMG IN SOUTH CENTRAL INDIANA AT 07Z. THIS IS FURTHER NORTH THAN EVEN THE NAM-WRF BUT CLOSE TO RUC40. LATEST 3HR PRESSURE FALLS ARE CENTERED ACROSS NORTHEAST INDIANA AND INTO NORTHWEST OHIO...INDICATING LOW WILL CONTINUE TO TRACK NORTHEAST. SINCE WE HAVE BEEN EXPECTING THIS...CURRENT GRIDS ARE IN RELATIVELY GOOD SHAPE. SURFACE TEMPERATURES HOVERING NEAR 30 ACROSS FAR NORTH WHERE WARNING IS IN PLACE...RIGHT AROUND 32 IN ADVISORY AREA...AND 33 TO 35 IN SOUTH WITH MODERATE TO HEAVY RAIN. EXPECT TEMPS TO RISE MAYBE A DEGREE IN THE NORTH THIS MORNING BUT SEVERAL DEGREES IN THE SOUTHEAST AS SURFACE LOW TRACKS TO NEAR KAOH AND WARM AIR SURGES NORTH. RUC40 HAS A GOOD HANDLE ON SURFACE LOW AND TEMPS SO USED THIS ALONG WITH ETA12 FOR TEMPS TODAY. PLAN ON LEAVING HEADLINES AS IS WITH INITIAL ISSUANCE GIVEN WIDESPREAD RAIN AND FREEZING RAIN STILL ACROSS ENTIRE AREA. EXPECT PCPN TO DIMINISH IN WEST SHORTLY WITH DECREASING TREND ACROSS CWA THIS MORNING. COLDER AIR ALREADY MAKING A MOVE WITH SURFACE OBS IN WESTERN MICHIGAN SHOWING FALLING TEMPS AND NORTH WINDS. EXPECT RESIDUAL DRIZZLE OR FREEZING DRIZZLE LATER IN THE MORNING THEN LIGHT SNOW OR FLURRIES THIS AFTERNOON. NOT GOING TO GET THAT DETAILED WITH GRIDS. WILL TRANSITION FROM CURRENT RAIN TO LIGHT SNOW CHANCES THIS AFTERNOON. HAVE ISSUED SEVERAL FLOOD WARNINGS FOR RIVERS EARLY THIS MORNING. WILL HOLD ONTO FLOOD WATCH UNTIL RAIN ENDS. FOCUS THEN SHIFTS TO LAKE EFFECT POTENTIAL TONIGHT AND INTO TUESDAY. AS SURFACE LOW MOVES EAST...ARCTIC AIR PLUNGES INTO FORECAST AREA WITH 850MB TEMPS DROPPING TO -12 TO -14C TONIGHT AND TO NEAR -16C ON TUESDAY. THIS COUPLED WITH WARM LAKE TEMPERATURES AROUND 5C YIELDS DELTA T VALUES AROUND 20C. THIS EXTREME INSTABILITY WILL BE COUPLED WITH HIGH LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET AND LAKE INDUCED CAPE NEARING 600 J/KG TUE MORNING. SYNOPTIC SETUP REMAINS FAVORABLE WITH SURFACE LOW TO THE EAST AND ARCTIC HIGH IN THE PLAINS CREATING A NEARLY NORTHERLY CYCLONIC FETCH DOWN LENGTH OF LAKE MICHIGAN. THIS USUALLY ALLOWS PRECONDITIONING FROM LAKE SUPERIOR AS WELL. NAM-WRF AND EVEN GFS CONTINUE TO PICK UP ON THESE FEATURES AND GENERATE STRONG 925-850MB OMEGA FROM 00Z TUE THROUGH 18Z TUE. THE NEGATIVE FACTOR REMAINS THE WIND SHEAR NEAR THE TOP OF THE MIXED LAYER...AS NOTED BY PREVIOUS DAY SHIFT. 700MB WIND COMPONENT STILL REMAINS MORE WESTERLY THAN LOWER LEVELS. ALSO A BIT CONCERNED FOR UPSTREAM SHORT WAVE THAT DROPS SOUTH LATE TONIGHT. THESE WAVES HAVE BEEN KNOWN TO DISRUPT BANDS AND LIMIT HEAVY ACCUMULATIONS. AFTER WEIGHING ALL THE PROS AND CONS...FEEL ENOUGH ELEMENTS IN PLACE TO WARRANT A LAKE EFFECT SNOW WATCH FOR TONIGHT AND TUESDAY. GIVEN THE NAM-WRF PLUME ANALYSIS SHOWING POTENTIAL WAVY BAND AND TO ACCOUNT FOR MODELS WESTWARD BIAS...HAVE MADE THE WATCH AREA FAIRLY LARGE...ENCOMPASSING WESTERN AREAS FOR POTENTIAL SINGLE BAND DOWN THE LENGTH OF LAKE...BUT ALSO ADDING CASS...ELKHART AND KOSCIUSKO GIVEN PLUME ANALYSIS OF 925-850MB OMEGA FIELDS AND MODEL BIAS. WILL HIT POTENTIAL FOR 6 TO 10 INCHES WITH THIS EVENT GIVEN THE MOVEMENT OF SINGLE BAND. HOWEVER...IF THIS TYPE I BAND IS REALIZED AND BECOMES STATIONARY FOR A PERIOD OF TIME...LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE. LONG TERM... TUESDAY NIGHT THROUGH SUNDAY...LAKE EFFECT SNOW SHOULD BE DIMINISHING TUESDAY NIGHT AS INVERSION HEIGHTS FALL AND AS WINDS BACK TO THE WEST AND SOUTHWEST. THE GFS CONTINUES TO RETREAT ON THE VERY COLD AIR ADVERTISED DURING THE MIDDLE OF THE WEEK ON SEVERAL PREVIOUS RUNS. HIGHS WEDNESDAY WERE IN THE LOWER 20S ON PREVIOUS MEX MOS...BUT NOW IN THE MID 30S. CAN NOT SEEM TO GET ANY COLD IN HERE AS THE LAST DAY BELOW NORMAL WAS DECEMBER 9. NEXT UPPER TROF WILL DROP RAPIDLY SOUTH LATE THIS WEEK OVER THE WEST CONUS AS THE DOWNSTREAM TROF OVER THE MIDWEST MOVES RAPIDLY EAST. HAVE RAISED HIGH AND LOWS TEMPS SOME TO ACCOMMODATE THIS PATTERN. THE NEXT CHANCE FOR PRECIPITATION WILL ARRIVE LATE IN THE WEEK AS THIS NEXT SYSTEM MOVES EAST INTO THE FORECAST AREA. THE GFS AND ECMWF WERE BRINGING COLDER AIR IN FRIDAY...WITH 850 MB TEMP DROPPING TO -20C BY LATE IN THE DAY. LAKE EFFECT SNOW IN ONGOING GRIDS/ZFP LOOKS GOOD. ONCE AGAIN...THIS TROF SHOULD LIFT EAST AS ANOTHER DEEP TROF DIGS OVER THE WESTERN CONUS. THE ECMWF WAS EVEN INDICATING SOME NEGATIVE TILT WITH THIS TROF...BUT THE MAIN WEATHER INDICATION FOR THE FORECAST AREA WILL BE LAKE EFFECT ENDING LATE SATURDAY WITH TEMPERATURES RETURNING TO NORMAL BY SUNDAY. NEW CANADIAN ENSEMBLE MEMBERS SUPPORT THIS PATTERN WITH A BROAD TROF OVER THE CENTRAL UNITED STATES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR INZ003-INZ004-INZ005-INZ012-INZ014-INZ016. MI...LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. && $$ UPDATE...HITCHCOCK SHORT TERM/AVIATION...LASHLEY LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 640 AM EST MON JAN 15 2007 .AVIATION... RADAR SHOWING PCPN ENDING AT BOTH SITES. SOME LIGHT DRIZZLE OR FLURRIES POSSIBLE THIS MORNING. WRAP AROUND MOISTURE THIS AFTERNOON WITH SHORT WAVE MAY BRING SNOW SHOWERS BACK TO THE AREA WITH COLD AIR ADVECTION. BEEN A BIT MORE OPTIMISTIC WITH VIS. LAKE EFFECT SNOW SHOWERS TONIGHT...ESPECIALLY AT KSBN. DROPPED VIS TO 1SM THERE BUT LOWER RESTRICTIONS CERTAINLY POSSIBLE AND EXPECTED. WILL REFINE AS EVENT DRAWS CLOSER AND SNOW BAND BECOMES EVIDENT ON RADAR. && .UPDATE... TEMPERATURES HAVE WARMED ABOVE FREEZING MOST AREAS. SURFACE LOW TRACKING TO NEAR KAOH AT 11Z AND ALLOWED WARM SURGE OF AIR INTO THE AREA. FAR NORTHEAST HANGING AROUND 32F WITH RAIN ENDING. WITH MOST ICING OVER AND MOST TEMPS ABOVE FREEZING...HAVE CANCELLED HEADLINES. WILL HAVE TO SEE HOW MUCH FREEZING DRIZZLE DEVELOPS FOR ANY POSSIBLE ADVISORIES...BUT TEMPS HOVERING NEAR 32 TO 34 AND POTENT DRY SLOT...THIS MAY NOT BE AN ISSUE. COLD AIR ADVECTION THIS MORNING SHOULD COOL COLUMN ENOUGH FOR CHANGEOVER TO FLURRIES OR LIGHT SNOW WITH NEXT SHORT WAVE. CONTINUED FLOOD WATCH WHERE RAIN STILL OCCURRING. SOUTHEAST AREAS HAVE SEEN MOST RAIN AND WILL EXPERIENCE MOST PROBLEMS. && .SHORT TERM... TODAY AND TONIGHT... ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE TONIGHT AND TUESDAY... NUMEROUS ISSUES IN THE SHORT TERM BEGINNING WITH ONGOING HEADLINES AND ENDING WITH HEAVY LAKE EFFECT SNOW POTENTIAL TONIGHT INTO TUESDAY. AS WE HAVE BEEN SAYING FOR DAYS...SURFACE LOW IS TRACKING WELL NORTHWEST OF WHERE MODELS HAD BEEN INDICATING...CURRENTLY NEAR KBMG IN SOUTH CENTRAL INDIANA AT 07Z. THIS IS FURTHER NORTH THAN EVEN THE NAM-WRF BUT CLOSE TO RUC40. LATEST 3HR PRESSURE FALLS ARE CENTERED ACROSS NORTHEAST INDIANA AND INTO NORTHWEST OHIO...INDICATING LOW WILL CONTINUE TO TRACK NORTHEAST. SINCE WE HAVE BEEN EXPECTING THIS...CURRENT GRIDS ARE IN RELATIVELY GOOD SHAPE. SURFACE TEMPERATURES HOVERING NEAR 30 ACROSS FAR NORTH WHERE WARNING IS IN PLACE...RIGHT AROUND 32 IN ADVISORY AREA...AND 33 TO 35 IN SOUTH WITH MODERATE TO HEAVY RAIN. EXPECT TEMPS TO RISE MAYBE A DEGREE IN THE NORTH THIS MORNING BUT SEVERAL DEGREES IN THE SOUTHEAST AS SURFACE LOW TRACKS TO NEAR KAOH AND WARM AIR SURGES NORTH. RUC40 HAS A GOOD HANDLE ON SURFACE LOW AND TEMPS SO USED THIS ALONG WITH ETA12 FOR TEMPS TODAY. PLAN ON LEAVING HEADLINES AS IS WITH INITIAL ISSUANCE GIVEN WIDESPREAD RAIN AND FREEZING RAIN STILL ACROSS ENTIRE AREA. EXPECT PCPN TO DIMINISH IN WEST SHORTLY WITH DECREASING TREND ACROSS CWA THIS MORNING. COLDER AIR ALREADY MAKING A MOVE WITH SURFACE OBS IN WESTERN MICHIGAN SHOWING FALLING TEMPS AND NORTH WINDS. EXPECT RESIDUAL DRIZZLE OR FREEZING DRIZZLE LATER IN THE MORNING THEN LIGHT SNOW OR FLURRIES THIS AFTERNOON. NOT GOING TO GET THAT DETAILED WITH GRIDS. WILL TRANSITION FROM CURRENT RAIN TO LIGHT SNOW CHANCES THIS AFTERNOON. HAVE ISSUED SEVERAL FLOOD WARNINGS FOR RIVERS EARLY THIS MORNING. WILL HOLD ONTO FLOOD WATCH UNTIL RAIN ENDS. FOCUS THEN SHIFTS TO LAKE EFFECT POTENTIAL TONIGHT AND INTO TUESDAY. AS SURFACE LOW MOVES EAST...ARCTIC AIR PLUNGES INTO FORECAST AREA WITH 850MB TEMPS DROPPING TO -12 TO -14C TONIGHT AND TO NEAR -16C ON TUESDAY. THIS COUPLED WITH WARM LAKE TEMPERATURES AROUND 5C YIELDS DELTA T VALUES AROUND 20C. THIS EXTREME INSTABILITY WILL BE COUPLED WITH HIGH LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET AND LAKE INDUCED CAPE NEARING 600 J/KG TUE MORNING. SYNOPTIC SETUP REMAINS FAVORABLE WITH SURFACE LOW TO THE EAST AND ARCTIC HIGH IN THE PLAINS CREATING A NEARLY NORTHERLY CYCLONIC FETCH DOWN LENGTH OF LAKE MICHIGAN. THIS USUALLY ALLOWS PRECONDITIONING FROM LAKE SUPERIOR AS WELL. NAM-WRF AND EVEN GFS CONTINUE TO PICK UP ON THESE FEATURES AND GENERATE STRONG 925-850MB OMEGA FROM 00Z TUE THROUGH 18Z TUE. THE NEGATIVE FACTOR REMAINS THE WIND SHEAR NEAR THE TOP OF THE MIXED LAYER...AS NOTED BY PREVIOUS DAY SHIFT. 700MB WIND COMPONENT STILL REMAINS MORE WESTERLY THAN LOWER LEVELS. ALSO A BIT CONCERNED FOR UPSTREAM SHORT WAVE THAT DROPS SOUTH LATE TONIGHT. THESE WAVES HAVE BEEN KNOWN TO DISRUPT BANDS AND LIMIT HEAVY ACCUMULATIONS. AFTER WEIGHING ALL THE PROS AND CONS...FEEL ENOUGH ELEMENTS IN PLACE TO WARRANT A LAKE EFFECT SNOW WATCH FOR TONIGHT AND TUESDAY. GIVEN THE NAM-WRF PLUME ANALYSIS SHOWING POTENTIAL WAVY BAND AND TO ACCOUNT FOR MODELS WESTWARD BIAS...HAVE MADE THE WATCH AREA FAIRLY LARGE...ENCOMPASSING WESTERN AREAS FOR POTENTIAL SINGLE BAND DOWN THE LENGTH OF LAKE...BUT ALSO ADDING CASS...ELKHART AND KOSCIUSKO GIVEN PLUME ANALYSIS OF 925-850MB OMEGA FIELDS AND MODEL BIAS. WILL HIT POTENTIAL FOR 6 TO 10 INCHES WITH THIS EVENT GIVEN THE MOVEMENT OF SINGLE BAND. HOWEVER...IF THIS TYPE I BAND IS REALIZED AND BECOMES STATIONARY FOR A PERIOD OF TIME...LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE. && .LONG TERM... TUESDAY NIGHT THROUGH SUNDAY...LAKE EFFECT SNOW SHOULD BE DIMINISHING TUESDAY NIGHT AS INVERSION HEIGHTS FALL AND AS WINDS BACK TO THE WEST AND SOUTHWEST. THE GFS CONTINUES TO RETREAT ON THE VERY COLD AIR ADVERTISED DURING THE MIDDLE OF THE WEEK ON SEVERAL PREVIOUS RUNS. HIGHS WEDNESDAY WERE IN THE LOWER 20S ON PREVIOUS MEX MOS...BUT NOW IN THE MID 30S. CAN NOT SEEM TO GET ANY COLD IN HERE AS THE LAST DAY BELOW NORMAL WAS DECEMBER 9. NEXT UPPER TROF WILL DROP RAPIDLY SOUTH LATE THIS WEEK OVER THE WEST CONUS AS THE DOWNSTREAM TROF OVER THE MIDWEST MOVES RAPIDLY EAST. HAVE RAISED HIGH AND LOWS TEMPS SOME TO ACCOMMODATE THIS PATTERN. THE NEXT CHANCE FOR PRECIPITATION WILL ARRIVE LATE IN THE WEEK AS THIS NEXT SYSTEM MOVES EAST INTO THE FORECAST AREA. THE GFS AND ECMWF WERE BRINGING COLDER AIR IN FRIDAY...WITH 850 MB TEMP DROPPING TO -20C BY LATE IN THE DAY. LAKE EFFECT SNOW IN ONGOING GRIDS/ZFP LOOKS GOOD. ONCE AGAIN...THIS TROF SHOULD LIFT EAST AS ANOTHER DEEP TROF DIGS OVER THE WESTERN CONUS. THE ECMWF WAS EVEN INDICATING SOME NEGATIVE TILT WITH THIS TROF...BUT THE MAIN WEATHER INDICATION FOR THE FORECAST AREA WILL BE LAKE EFFECT ENDING LATE SATURDAY WITH TEMPERATURES RETURNING TO NORMAL BY SUNDAY. NEW CANADIAN ENSEMBLE MEMBERS SUPPORT THIS PATTERN WITH A BROAD TROF OVER THE CENTRAL UNITED STATES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR INZ023-INZ024-INZ025-INZ026-INZ027-INZ032-INZ033-INZ034. LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR INZ003-INZ004-INZ005-INZ012-INZ014-INZ016. MI...LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR MIZ077-MIZ078. OH...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR OHZ016-OHZ024- OHZ025. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...LASHLEY LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 401 AM EST MON JAN 15 2007 .SHORT TERM... TODAY AND TONIGHT... ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE TONIGHT AND TUESDAY... NUMEROUS ISSUES IN THE SHORT TERM BEGINNING WITH ONGOING HEADLINES AND ENDING WITH HEAVY LAKE EFFECT SNOW POTENTIAL TONIGHT INTO TUESDAY. AS WE HAVE BEEN SAYING FOR DAYS...SURFACE LOW IS TRACKING WELL NORTHWEST OF WHERE MODELS HAD BEEN INDICATING...CURRENTLY NEAR KBMG IN SOUTH CENTRAL INDIANA AT 07Z. THIS IS FURTHER NORTH THAN EVEN THE NAM-WRF BUT CLOSE TO RUC40. LATEST 3HR PRESSURE FALLS ARE CENTERED ACROSS NORTHEAST INDIANA AND INTO NORTHWEST OHIO...INDICATING LOW WILL CONTINUE TO TRACK NORTHEAST. SINCE WE HAVE BEEN EXPECTING THIS...CURRENT GRIDS ARE IN RELATIVELY GOOD SHAPE. SURFACE TEMPERATURES HOVERING NEAR 30 ACROSS FAR NORTH WHERE WARNING IS IN PLACE...RIGHT AROUND 32 IN ADVISORY AREA...AND 33 TO 35 IN SOUTH WITH MODERATE TO HEAVY RAIN. EXPECT TEMPS TO RISE MAYBE A DEGREE IN THE NORTH THIS MORNING BUT SEVERAL DEGREES IN THE SOUTHEAST AS SURFACE LOW TRACKS TO NEAR KAOH AND WARM AIR SURGES NORTH. RUC40 HAS A GOOD HANDLE ON SURFACE LOW AND TEMPS SO USED THIS ALONG WITH ETA12 FOR TEMPS TODAY. PLAN ON LEAVING HEADLINES AS IS WITH INITIAL ISSUANCE GIVEN WIDESPREAD RAIN AND FREEZING RAIN STILL ACROSS ENTIRE AREA. EXPECT PCPN TO DIMINISH IN WEST SHORTLY WITH DECREASING TREND ACROSS CWA THIS MORNING. COLDER AIR ALREADY MAKING A MOVE WITH SURFACE OBS IN WESTERN MICHIGAN SHOWING FALLING TEMPS AND NORTH WINDS. EXPECT RESIDUAL DRIZZLE OR FREEZING DRIZZLE LATER IN THE MORNING THEN LIGHT SNOW OR FLURRIES THIS AFTERNOON. NOT GOING TO GET THAT DETAILED WITH GRIDS. WILL TRANSITION FROM CURRENT RAIN TO LIGHT SNOW CHANCES THIS AFTERNOON. HAVE ISSUED SEVERAL FLOOD WARNINGS FOR RIVERS EARLY THIS MORNING. WILL HOLD ONTO FLOOD WATCH UNTIL RAIN ENDS. FOCUS THEN SHIFTS TO LAKE EFFECT POTENTIAL TONIGHT AND INTO TUESDAY. AS SURFACE LOW MOVES EAST...ARCTIC AIR PLUNGES INTO FORECAST AREA WITH 850MB TEMPS DROPPING TO -12 TO -14C TONIGHT AND TO NEAR -16C ON TUESDAY. THIS COUPLED WITH WARM LAKE TEMPERATURES AROUND 5C YIELDS DELTA T VALUES AROUND 20C. THIS EXTREME INSTABILITY WILL BE COUPLED WITH HIGH LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET AND LAKE INDUCED CAPE NEARING 600 J/KG TUE MORNING. SYNOPTIC SETUP REMAINS FAVORABLE WITH SURFACE LOW TO THE EAST AND ARCTIC HIGH IN THE PLAINS CREATING A NEARLY NORTHERLY CYCLONIC FETCH DOWN LENGTH OF LAKE MICHIGAN. THIS USUALLY ALLOWS PRECONDITIONING FROM LAKE SUPERIOR AS WELL. NAM-WRF AND EVEN GFS CONTINUE TO PICK UP ON THESE FEATURES AND GENERATE STRONG 925-850MB OMEGA FROM 00Z TUE THROUGH 18Z TUE. THE NEGATIVE FACTOR REMAINS THE WIND SHEAR NEAR THE TOP OF THE MIXED LAYER...AS NOTED BY PREVIOUS DAY SHIFT. 700MB WIND COMPONENT STILL REMAINS MORE WESTERLY THAN LOWER LEVELS. ALSO A BIT CONCERNED FOR UPSTREAM SHORT WAVE THAT DROPS SOUTH LATE TONIGHT. THESE WAVES HAVE BEEN KNOWN TO DISRUPT BANDS AND LIMIT HEAVY ACCUMULATIONS. AFTER WEIGHING ALL THE PROS AND CONS...FEEL ENOUGH ELEMENTS IN PLACE TO WARRANT A LAKE EFFECT SNOW WATCH FOR TONIGHT AND TUESDAY. GIVEN THE NAM-WRF PLUME ANALYSIS SHOWING POTENTIAL WAVY BAND AND TO ACCOUNT FOR MODELS WESTWARD BIAS...HAVE MADE THE WATCH AREA FAIRLY LARGE...ENCOMPASSING WESTERN AREAS FOR POTENTIAL SINGLE BAND DOWN THE LENGTH OF LAKE...BUT ALSO ADDING CASS...ELKHART AND KOSCIUSKO GIVEN PLUME ANALYSIS OF 925-850MB OMEGA FIELDS AND MODEL BIAS. WILL HIT POTENTIAL FOR 6 TO 10 INCHES WITH THIS EVENT GIVEN THE MOVEMENT OF SINGLE BAND. HOWEVER...IF THIS TYPE I BAND IS REALIZED AND BECOMES STATIONARY FOR A PERIOD OF TIME...LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE. && .LONG TERM... TUESDAY NIGHT THROUGH SUNDAY...LAKE EFFECT SNOW SHOULD BE DIMINISHING TUESDAY NIGHT AS INVERSION HEIGHTS FALL AND AS WINDS BACK TO THE WEST AND SOUTHWEST. THE GFS CONTINUES TO RETREAT ON THE VERY COLD AIR ADVERTISED DURING THE MIDDLE OF THE WEEK ON SEVERAL PREVIOUS RUNS. HIGHS WEDNESDAY WERE IN THE LOWER 20S ON PREVIOUS MEX MOS...BUT NOW IN THE MID 30S. CAN NOT SEEM TO GET ANY COLD IN HERE AS THE LAST DAY BELOW NORMAL WAS DECEMBER 9. NEXT UPPER TROF WILL DROP RAPIDLY SOUTH LATE THIS WEEK OVER THE WEST CONUS AS THE DOWNSTREAM TROF OVER THE MIDWEST MOVES RAPIDLY EAST. HAVE RAISED HIGH AND LOWS TEMPS SOME TO ACCOMMODATE THIS PATTERN. THE NEXT CHANCE FOR PRECIPITATION WILL ARRIVE LATE IN THE WEEK AS THIS NEXT SYSTEM MOVES EAST INTO THE FORECAST AREA. THE GFS AND ECMWF WERE BRINGING COLDER AIR IN FRIDAY...WITH 850 MB TEMP DROPPING TO -20C BY LATE IN THE DAY. LAKE EFFECT SNOW IN ONGOING GRIDS/ZFP LOOKS GOOD. ONCE AGAIN...THIS TROF SHOULD LIFT EAST AS ANOTHER DEEP TROF DIGS OVER THE WESTERN CONUS. THE ECMWF WAS EVEN INDICATING SOME NEGATIVE TILT WITH THIS TROF...BUT THE MAIN WEATHER INDICATION FOR THE FORECAST AREA WILL BE LAKE EFFECT ENDING LATE SATURDAY WITH TEMPERATURES RETURNING TO NORMAL BY SUNDAY. NEW CANADIAN ENSEMBLE MEMBERS SUPPORT THIS PATTERN WITH A BROAD TROF OVER THE CENTRAL UNITED STATES. && .AVIATION... WIDESPREAD RAIN AND FREEZING RAIN ACROSS THE AREA TONIGHT. KFWA HOVERING JUST ABOVE FREEZING AND KSBN RIGHT AT FREEZING. PREDOMINATE FREEZING RAIN EXPECTED AT KSBN REST OF NIGHT WHILE FORT WAYNE LIKELY TO BE MAINLY RAIN BUT FREEZING AT TIMES WITH TEMPERATURE WAVERING BETWEEN 32 AND 33. LARGE RAIN SHIELD EXTENDS BACK INTO IL SO EXPECT THIS TO CONTINUE NEXT SEVERAL HOURS. DRY SLOT WORKS IN AFTER DAYBREAK BUT ENOUGH LOW LEVEL RESIDUAL MOISTURE TO SUPPORT FREEZING DRIZZLE OR FLURRIES WITH VIS RESTRICTIONS DUE TO BR. LAKE EFFECT SNOW BAND EXPECTED TO SET UP LATE THIS AFTERNOON INTO EARLY EVENING. HAVE ONLY TAKEN SBN VIS DOWN TO 3SM -SN FOR NOW GIVEN UNCERTAINTY OF WHERE BAND WILL BE. VERY LIKELY MUCH LOWER RESTRICTIONS AND POSSIBLE HEAVY SNOW WILL BE NEEDED FROM BETWEEN 03Z AND 12Z TUE. MORE REFINEMENT IN LATER ISSUANCES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR INZ020-INZ022- INZ023-INZ024-INZ025-INZ026-INZ027-INZ032-INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR INZ008-INZ009-INZ012-INZ013-INZ014-INZ015-INZ016-INZ017- INZ018. ICE STORM WARNING UNTIL NOON EST /11 AM CST/ TODAY FOR INZ003- INZ004-INZ005-INZ006-INZ007. LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR INZ003-INZ004-INZ005-INZ012-INZ014-INZ016. MI...ICE STORM WARNING UNTIL NOON EST TODAY FOR MIZ077-MIZ078-MIZ079- MIZ080-MIZ081. LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR MIZ077-MIZ078. OH...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR OHZ016-OHZ024- OHZ025. FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR OHZ004-OHZ005- OHZ015. ICE STORM WARNING UNTIL NOON EST TODAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...LASHLEY LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 AM EST MON JAN 15 2007 .AVIATION... WIDESPREAD RAIN AND FREEZING RAIN ACROSS THE AREA TONIGHT. KFWA HOVERING JUST ABOVE FREEZING AND KSBN RIGHT AT FREEZING. PREDOMINATE FREEZING RAIN EXPECTED AT KSBN REST OF NIGHT WHILE FORT WAYNE LIKELY TO BE MAINLY RAIN BUT FREEZING AT TIMES WITH TEMPERATURE WAVERING BETWEEN 32 AND 33. LARGE RAIN SHIELD EXTENDS BACK INTO IL SO EXPECT THIS TO CONTINUE NEXT SEVERAL HOURS. DRY SLOT WORKS IN AFTER DAYBREAK BUT ENOUGH LOW LEVEL RESIDUAL MOISTURE TO SUPPORT FREEZING DRIZZLE OR FLURRIES WITH VIS RESTRICTIONS DUE TO BR. LAKE EFFECT SNOW BAND EXPECTED TO SET UP LATE THIS AFTERNOON INTO EARLY EVENING. HAVE ONLY TAKEN SBN VIS DOWN TO 3SM -SN FOR NOW GIVEN UNCERTAINTY OF WHERE BAND WILL BE. VERY LIKELY MUCH LOWER RESTRICTIONS AND POSSIBLE HEAVY SNOW WILL BE NEEDED FROM BETWEEN 03Z AND 12Z TUE. MORE REFINEMENT IN LATER ISSUANCES. && .UPDATE... GETTING 1/8" GLAZING REPORTS ON TREES JUST NORTH OF SOUTH BEND LATE THIS EVE. BASED ON SFC OBS EXPECT SIMILAR CONDITIONS THROUGHOUT THE ADVISORY AREA WITH THE PSBL EXCEPTION OF URBAN AREAS OF SOUTH BEND/ELKHART DECIDED TO UPGRADE FREEZING RAIN ADVISORY TO AN ICE STORM WARNING. ALSO GETTING SCT REPORTS OF ICING FARTHER SOUTH AND WITH DFI TEMP AT 32 LAST SEVERAL HOURS AND FWA TEMP/DWPT FALLING SLOWLY, WILL ISSUE FREEZING RAIN ADVISORY AREA SOUTH OF ICE STORM WARNING A COUPLE TIERS OF COUNTIES. EXPECT ICING IN THIS AREA WILL MAINLY BE ON ELEVATED SURFACES, BUT STILL COULD BE SUFFICIENT TO CAUSE SOME PROBLEMS. && .PREV DISCUSSION... PREVIOUS UPDATE... EVE RAOB/TAMDAR SOUNDINGS SHOWING WARM LAYER OF GENERALLY +2 TO +6C OVER OUR AREA RESULTING IN INITIAL PRECIP REACHING THE GROUND AS RN/ZR. SFC OBS AND CALLS TO POLICE IN THE AREA INDICATE SO FAR ONLY PATCHY REPORTS OF GLAZING IN NRN INDIANA AND NW OH EVEN THOUGH SOME ASOS/AWOS SITES REPORTING TEMPS AT FREEZING. THIS PRBLY A RESULT OF TEMPERATURE OF HEAVY RAINFALL GENERALLY REACHING THE GROUND ABOVE FREEZING. IN MICHIGAN WHERE SFC TEMPS HAVE BEEN RUNNING A DEGREE OR TWO BELOW FREEZING ALL DAY AND THIS EVE, MORE WIDESPREAD GLAZING IS BEING REPORTED. WITH WAA OVERNIGHT AS SFC LOW MOVES NE FROM SRN MO TO WEST CENTRAL OH, THE RN/SN LINE, WHICH IS EXPECTED TO SETUP FROM JUST NORTH OF CHICAGO TO JUST NORTH OF DETROIT THIS EVE, WILL PRBLY SHIFT SLIGHTLY NORTH. THUS, AS IN GOING FCST STILL EXPECTING A MAINLY LIQUID EVENT WITH MAIN THREAT FOR ICE ACCUMULATIONS ACROSS OUR NRN COUNTIES. MAIN QUESTIONS ARE HOW MUCH OF THE HEAVY RAIN WILL ACCUMULATE AS ICE IN THE ADVISORY AREAS AND IF SFC TEMPS WILL FALL SUFFICIENTLY SOUTH OF THE ADVISORY AREA TO WARRANT EXPANSION. FOR NOW FEEL THINGS ARE ON TRACK AND WILL CONTINUE TO MONITOR BUT NO CHANGES TO HEADLINES OR FCSTS PLANNED THIS EVE. SHORT TERM... TONIGHT AND MONDAY. ...SIGNIFICANT ICING EXPECTED ACROSS SOUTHERN LOWER MICHIGAN TONIGHT INTO MONDAY MORNING... ...SOME ICING EXPECTED ACROSS NORTHERN INDIANA AND NORTHWEST OHIO TONIGHT AND MONDAY... 12Z NAM-WRF AND 12Z GFS CONTINUE TO TREND NEXT WAVE OF LOW PRESSURE FARTHER NORTHWEST. THE NAM-WRF IS THE FARTHEST NORTHWEST OF THE TWO...PLACING THE WAVE OF LOW PRESSURE OVER NW OHIO BY 12Z MONDAY. BASED ON THE TREND OF BRINGING THE LOW FARTHER NORTHWEST...FEEL MORE INCLINED TO SIDE WITH THE NAM-WRF AND THUS WILL USE ITS SOLUTION AS A BACKBONE TO THE SHORT TERM FORECAST. ITS WARMER THERMAL PROFILE WILL RESULT IN MOSTLY FREEZING RAIN TONIGHT ACRS THE NRN CWFA. AT 20Z...LOW PRESSURE WAS DEVELOPING ALONG A STATIONARY FRONT OVER NW ARKANSAS. AS A STRONG S/WV AND JET PIVOT NORTHEAST INTO THE CNTRL PLAINS TONIGHT AND THEN INTO THE WRN GREAT LAKES ON MONDAY...THE LOW WILL MOVE NORTHEAST AND DEEPEN WITH TIME...BEING LOCATED NEAR SW INDIANA AT 06Z MONDAY AND NEAR NW OHIO BY 12Z MONDAY. THE LOW WILL BE ASSOCIATED WITH STRONG...MOIST LOW LVL WARM ADVECTION. THIS STRONG ASCENT WILL TEAM UP WITH UPR LVL DIVERGENCE FROM A STRONG JET ALOFT. THIS WILL RESULT IN WIDESPREAD PCPN ACRS THE CWFA OVERNIGHT. IN FACT...LATEST MOSAIC RADAR WAS SHOWING A LARGE AREA OF PCPN BLOSSOMING ACRS THE CNTRL AND SRN PLAINS. THIS PCPN WILL CONTINUE TO EXPAND AND MOVE NE INTO THE REGION TONIGHT. THERE IS A LOT TO BE CONCERNED ABOUT OVERNIGHT INTO THE FIRST PART OF MONDAY AS COLD AIR REMAINS TRAPPED NEAR THE SFC ACRS THE FAR NRN CWFA. LATEST OBSERVATIONS SHOW TEMPS HOVERING BETWEEN 30 AND 33 DEGREES ACRS FAR NRN INDIANA...SOUTHERN LOWER MICHIGAN AND FAR NORTHWEST OHIO. THESE TEMPS WILL NOT BUDGE MUCH OVERNIGHT...AND MAY SLIGHTLY DROP A DEGREE OR TWO. FOR THE REMAINDER OF THE REGION...TEMPS WILL REMAIN STEADY STATE IN THE LOWER TO MID 30S...EXPECT FOR THE FAR SOUTHEAST WHERE WARMER AIR WILL BE PULLED WESTWARD AS THE LOW APPROACHES. WITH ABOUT THREE QUARTERS TO AROUND ONE INCH OF QPF EXPECTED OVERNIGHT...SIGNIFICANT ICING WILL OCCUR ACRS THE MICHIGAN COUNTIES WHERE ABOUT A HALF INCH OF ICE ACCUMULATION IS EXPECTED. FOR THE FAR NRN INDIANA AND NORTHWEST OHIO COUNTIES...ICE ACCUMULATIONS WILL BE LESS THAN A QUARTER INCH. FARTHER SOUTH...MAINLY RAIN IS EXPECTED. AN ICE STORM WARNING WILL BE ISSUED FOR THE MICHIGAN COUNTIES UNTIL 17Z MONDAY...WHILE A FREEZING RAIN ADVISORY WILL BE ISSUED FOR THE FAR NRN INDIANA/NW OHIO COUNTIES THROUGH 17Z MONDAY. ADDITIONAL RAINFALL ACRS THE FAR SOUTH/SOUTHEAST WILL LIKELY LEAD TO RIVER FLOODING ALONG THE UPPER WABASH AND MAUMEE RIVER BASINS..SO WILL MAINTAIN FLOOD WATCH FOR THIS LOCATION THROUGH 18Z MONDAY. ON MONDAY...AS SFC LOW PRESSURE PULLS AWAY TO THE NE...COLDER AIR WILL BEGIN TO FILTER SE INTO THE FCST AREA. THERE WILL LIKELY BE FREEZING PCPN ACRS THE NW HALF OF THE CWFA...BUT THIS SHOULD BE ON THE LIGHT SIDE. FOR THE SOUTHEAST...LIGHT RAIN IS EXPECTED. MODELS CONTINUE TO SHOW A DRY SLOT WORKING INTO THE REGION BY MID MORNING. THIS MAY CHC PCPN TO DRIZZLE OR FREEZING DRIZZLE. HAVE OPTED TO GO WITH THE LIGHT FREEZING RAIN/LIGHT RAIN WORDING DUE TO LINGER PCPN EARLY IN THE MORNING IN ASSOCIATION WITH THE LOW AND FOR THE FACT THAT SOME OF THE DRIZZLE MAY MEASURE. AS COLDER AIR AND DEEPER ATMOSPHERIC MOISTURE FILTER INTO THE REGION DURING THE AFTERNOON...ANY DRIZZLE WILL CHANGEOVER TO SOME LIGHT SNOW. MAIN LAKE EFFECT EVENT LOOKS TO HOLD OFF UNTIL MONDAY NIGHT AND WILL LEAVE THOSE DETAILS TO THE LONG TERM FORECASTER. LONG TERM... MONDAY NIGHT THROUGH SUNDAY ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE MONDAY NIGHT THROUGH TUESDAY... MAIN CONCERN FOR THE LONG TERM TODAY REVOLVES AROUND LAKE EFFECT POTENTIAL AT THE START OF THE PERIOD. MODERATE LOW/MID LEVEL CAA FOLLOWING MAJOR FRONTAL WAVE ON MON WILL BRING MUCH COLDER AIR ACROSS THE LAKE WITH AMPLE LAKE INSTABILITY DEVELOPING. NEAR RECORD WARM LAKE TEMPERATURE OF AROUND 5C PER LATEST SATELLITE DERIVED DATA WILL CONTRIBUTE TO MODERATE COLLIER INDEX WITH LAKE INDUCED CAPE AROUND 500J/KG AND LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET. INSTABILITY IS CERTAINLY MORE THAN AMPLE...HOWEVER MUCH UNCERTAINTY LIES WITH BAND MODE...PLACEMENT...AND AMOUNT OF SHEAR. FROM A PATTERN RECOGNITION PROSPECTIVE...SETUP LOOKS VERY FAVORABLE WITH A 1040+MB HIGH BUILDING SOUTH THROUGH THE PLAINS AND FAVORABLE N/NNW FLOW DEVELOPING DOWN A SUBSTANTIAL FETCH OF LAKE MICHIGAN. A POTENTIAL NEGATIVE...BOTH NAM/GFS SUGGEST THERE WILL BE SOME SHEAR NEAR THE TOP OF THE LAKE INDUCED MIXED LAYER WITH A MORE WESTERLY COMPONENT AT 700MB AND MORE NW/NNW AT 850MB. NAM-WRF PLUME ANALYSIS CONTINUES TO SUGGEST THE POTENTIAL FOR A TYPE I LAKE EFFECT BAND...MEANING A DOMINANT BAND PARALLEL TO THE MAJOR AXIS OF THE LAKE. NAM-WRF HAS BEEN FLIP-FLOPPING WILDLY FROM RUN TO RUN WITH RESPECT TO DIRECTION OF LOW LEVEL FLOW...WITH 00Z AND 06Z RUNS SUGGESTING A NEAR DUE NORTH FETCH...WHILE 12Z RUN SUGGESTS MORE NW FETCH. A LOOK AT SOME OTHER MESOSCALE GUIDANCE SUCH AS THE FSL EXPERIMENTAL RUC AND THE CANADIAN GEM SHOW MORE UNCERTAINTY...WITH BOTH THOSE MODELS DEPICTING MORE NORTHERLY FLOW AND A MORE WESTWARD BAND PLACEMENT. TYPICAL BIAS OF MESOSCALE MODELS ARE TO BE TOO FAR WEST WITH A DOMINANT BAND AT THE SOUTHERN END OF LAKE MICHIGAN. WITH THE VERY POOR MODEL AGREEMENT AND CONSISTENCY...JUST NOT ENOUGH CONFIDENCE ON BAND PLACEMENT OR MODE TO GO WITH AN LES WATCH YET. STILL ENOUGH TIME FOR A SHORTER RANGE WATCH FROM THE MIDNIGHT SHIFT IF MODEL GUIDANCE STARTS TO CONVERGE ON A COMMON SOLUTION. THIS DOES HAVE THE POTENTIAL TO BE A MAJOR EVENT GIVEN STRONG THERMODYNAMICS...BUT ONLY IF A DOMINANT BAND FORMS...AND THAT IS STILL QUITE UNCERTAIN. CP SURFACE HIGH BUILDS ACROSS THE OHIO VALLEY LATER TUE NGT INTO WED WITH CRASHING INVERSION HEIGHTS AND BACKING LOW LEVEL FLOW CUTTING OFF ANY REMAINING LAKE EFFECT. SHOULD SEE A DRY PERIOD FOR WED AND THU WITH A MODERATING TREND AS HEIGHTS RISE IN RESPONSE TO DIGGING UPSTREAM TROUGH. VERY LITTLE CHANGE MADE TO CONTINUITY IN THE LATER PERIODS WITH PRIMARY CONCERNS IN SHORT TERM HIGH IMPACT WEATHER. STILL APPEARS THAT ONE OR SEVERAL CLIPPER TYPE SHORTWAVES WILL CROSS THE GREAT LAKES STARTING AT THE END OF THE WEEK AND HAVE CONTINUED WITH LOW CHANCE POPS...MAINLY ACROSS THE NORTHERN PORTION OF THE CWA. TEMPS WILL AVERAGE AROUND NORMAL FOR MUCH OF THE LONG TERM... BUT THIS WILL FEEL COLD AFTER THE INCREDIBLE STRETCH OF WARM WEATHER THE PAST MONTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR INZ020-INZ022-INZ023- INZ024-INZ025-INZ026-INZ027-INZ032-INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ008-INZ009-INZ012-INZ013-INZ014-INZ015-INZ016-INZ017- INZ018. ICE STORM WARNING UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ003- INZ004-INZ005-INZ006-INZ007. MI...ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OHZ016-OHZ024-OHZ025. FREEZING RAIN ADVISORY UNTIL 12 PM EST MONDAY FOR OHZ004-OHZ005- OHZ015. ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. $$ AVIATION/UPDATE...LASHLEY/TAYLOR SHORT TERM...HICKMAN LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1059 PM EST SUN JAN 14 2007 .UPDATE... GETTING 1/8" GLAZING REPORTS ON TREES JUST NORTH OF SOUTH BEND LATE THIS EVE. BASED ON SFC OBS EXPECT SIMILAR CONDITIONS THROUGHOUT THE ADVISORY AREA WITH THE PSBL EXCEPTION OF URBAN AREAS OF SOUTH BEND/ELKHART DECIDED TO UPGRADE FREEZING RAIN ADVISORY TO AN ICE STORM WARNING. ALSO GETTING SCT REPORTS OF ICING FARTHER SOUTH AND WITH DFI TEMP AT 32 LAST SEVERAL HOURS AND FWA TEMP/DWPT FALLING SLOWLY, WILL ISSUE FREEZING RAIN ADVISORY AREA SOUTH OF ICE STORM WARNING A COUPLE TIERS OF COUNTIES. EXPECT ICING IN THIS AREA WILL MAINLY BE ON ELEVATED SURFACES, BUT STILL COULD BE SUFFICIENT TO CAUSE SOME PROBLEMS. && .UPDATE... EVE RAOB/TAMDAR SOUNDINGS SHOWING WARM LAYER OF GENERALLY +2 TO +6C OVER OUR AREA RESULTING IN INITIAL PRECIP REACHING THE GROUND AS RN/ZR. SFC OBS AND CALLS TO POLICE IN THE AREA INDICATE SO FAR ONLY PATCHY REPORTS OF GLAZING IN NRN INDIANA AND NW OH EVEN THOUGH SOME ASOS/AWOS SITES REPORTING TEMPS AT FREEZING. THIS PRBLY A RESULT OF TEMPERATURE OF HEAVY RAINFALL GENERALLY REACHING THE GROUND ABOVE FREEZING. IN MICHIGAN WHERE SFC TEMPS HAVE BEEN RUNNING A DEGREE OR TWO BELOW FREEZING ALL DAY AND THIS EVE, MORE WIDESPREAD GLAZING IS BEING REPORTED. WITH WAA OVERNIGHT AS SFC LOW MOVES NE FROM SRN MO TO WEST CENTRAL OH, THE RN/SN LINE, WHICH IS EXPECTED TO SETUP FROM JUST NORTH OF CHICAGO TO JUST NORTH OF DETROIT THIS EVE, WILL PRBLY SHIFT SLIGHTLY NORTH. THUS, AS IN GOING FCST STILL EXPECTING A MAINLY LIQUID EVENT WITH MAIN THREAT FOR ICE ACCUMULATIONS ACROSS OUR NRN COUNTIES. MAIN QUESTIONS ARE HOW MUCH OF THE HEAVY RAIN WILL ACCUMULATE AS ICE IN THE ADVISORY AREAS AND IF SFC TEMPS WILL FALL SUFFICIENTLY SOUTH OF THE ADVISORY AREA TO WARRANT EXPANSION. FOR NOW FEEL THINGS ARE ON TRACK AND WILL CONTINUE TO MONITOR BUT NO CHANGES TO HEADLINES OR FCSTS PLANNED THIS EVE. && .AVIATION... ONLY MINOR CHANGES TO PREVIOUS TAFS. AREA OF LOW PRESSURE DVLPG OVER SWRN MO THIS EVE WAS CAUSING OVER-RUNNING PRECIP TO DVLP NORTH OF STNRY FRONT ALONG OH RVR. THIS SHOULD SPREAD INTO NRN INDIANA OVER THE NEXT COUPLE OF HOURS WITH HEAVIEST RAINFALL INITIALLY MOVG INTO THE FWA AREA. CIGS/VSBYS WERE ALREADY LOWERING IN ADVANCE OF THE RAINFALL THIS EVE APPARENTLY IN RESPONSE TO DIURNAL COOLING OF THE VERY MOIST LOW LEVELS. TEMPS EXPECTED TO REMAIN JUST COLD ENOUGH FOR FREEZING RAIN AT SBN AND JUST WARM ENOUGH FOR RAIN NOT TO FREEZE AT FWA AS THE LOW MOVES NE ACROSS SRN INDIANA TONIGHT. PRECIP INTENSITY SHOULD DIMINISH ON MONDAY AS MID LEVEL DRY SLOT MOVES OVER THE AREA. WITH COLD AIR WRAPPING AROUND THE LOW AS IT DEPARTS THE AREA TO OUR EAST ON MONDAY, PRECIP SHOULD CHANGE OVER TO SNOW AT SBN EARLY IN THE AFTN. POTENTIAL FOR LAKE ENHANCEMENT TO INTENSIFY SNOWFALL LATE AFTN BUT SINCE NEAR END OF TAF PD DID NOT ADD TO TAFS YET. LIKEWISE AT FWA COLDER AIR FILLING IN BEHIND THE LOW COULD CHANGE PRECIP TO -ZL OR -SN LATE IN THE AFTN BUT HELD OFF MENTIONING THIS CHANGE IN THE TAF FOR NOW. && .SHORT TERM... TONIGHT AND MONDAY. ...SIGNIFICANT ICING EXPECTED ACROSS SOUTHERN LOWER MICHIGAN TONIGHT INTO MONDAY MORNING... ...SOME ICING EXPECTED ACROSS NORTHERN INDIANA AND NORTHWEST OHIO TONIGHT AND MONDAY... 12Z NAM-WRF AND 12Z GFS CONTINUE TO TREND NEXT WAVE OF LOW PRESSURE FARTHER NORTHWEST. THE NAM-WRF IS THE FARTHEST NORTHWEST OF THE TWO...PLACING THE WAVE OF LOW PRESSURE OVER NW OHIO BY 12Z MONDAY. BASED ON THE TREND OF BRINGING THE LOW FARTHER NORTHWEST...FEEL MORE INCLINED TO SIDE WITH THE NAM-WRF AND THUS WILL USE ITS SOLUTION AS A BACKBONE TO THE SHORT TERM FORECAST. ITS WARMER THERMAL PROFILE WILL RESULT IN MOSTLY FREEZING RAIN TONIGHT ACRS THE NRN CWFA. AT 20Z...LOW PRESSURE WAS DEVELOPING ALONG A STATIONARY FRONT OVER NW ARKANSAS. AS A STRONG S/WV AND JET PIVOT NORTHEAST INTO THE CNTRL PLAINS TONIGHT AND THEN INTO THE WRN GREAT LAKES ON MONDAY...THE LOW WILL MOVE NORTHEAST AND DEEPEN WITH TIME...BEING LOCATED NEAR SW INDIANA AT 06Z MONDAY AND NEAR NW OHIO BY 12Z MONDAY. THE LOW WILL BE ASSOCIATED WITH STRONG...MOIST LOW LVL WARM ADVECTION. THIS STRONG ASCENT WILL TEAM UP WITH UPR LVL DIVERGENCE FROM A STRONG JET ALOFT. THIS WILL RESULT IN WIDESPREAD PCPN ACRS THE CWFA OVERNIGHT. IN FACT...LATEST MOSAIC RADAR WAS SHOWING A LARGE AREA OF PCPN BLOSSOMING ACRS THE CNTRL AND SRN PLAINS. THIS PCPN WILL CONTINUE TO EXPAND AND MOVE NE INTO THE REGION TONIGHT. THERE IS A LOT TO BE CONCERNED ABOUT OVERNIGHT INTO THE FIRST PART OF MONDAY AS COLD AIR REMAINS TRAPPED NEAR THE SFC ACRS THE FAR NRN CWFA. LATEST OBSERVATIONS SHOW TEMPS HOVERING BETWEEN 30 AND 33 DEGREES ACRS FAR NRN INDIANA...SOUTHERN LOWER MICHIGAN AND FAR NORTHWEST OHIO. THESE TEMPS WILL NOT BUDGE MUCH OVERNIGHT...AND MAY SLIGHTLY DROP A DEGREE OR TWO. FOR THE REMAINDER OF THE REGION...TEMPS WILL REMAIN STEADY STATE IN THE LOWER TO MID 30S...EXPECT FOR THE FAR SOUTHEAST WHERE WARMER AIR WILL BE PULLED WESTWARD AS THE LOW APPROACHES. WITH ABOUT THREE QUARTERS TO AROUND ONE INCH OF QPF EXPECTED OVERNIGHT...SIGNIFICANT ICING WILL OCCUR ACRS THE MICHIGAN COUNTIES WHERE ABOUT A HALF INCH OF ICE ACCUMULATION IS EXPECTED. FOR THE FAR NRN INDIANA AND NORTHWEST OHIO COUNTIES...ICE ACCUMULATIONS WILL BE LESS THAN A QUARTER INCH. FARTHER SOUTH...MAINLY RAIN IS EXPECTED. AN ICE STORM WARNING WILL BE ISSUED FOR THE MICHIGAN COUNTIES UNTIL 17Z MONDAY...WHILE A FREEZING RAIN ADVISORY WILL BE ISSUED FOR THE FAR NRN INDIANA/NW OHIO COUNTIES THROUGH 17Z MONDAY. ADDITIONAL RAINFALL ACRS THE FAR SOUTH/SOUTHEAST WILL LIKELY LEAD TO RIVER FLOODING ALONG THE UPPER WABASH AND MAUMEE RIVER BASINS..SO WILL MAINTAIN FLOOD WATCH FOR THIS LOCATION THROUGH 18Z MONDAY. ON MONDAY...AS SFC LOW PRESSURE PULLS AWAY TO THE NE...COLDER AIR WILL BEGIN TO FILTER SE INTO THE FCST AREA. THERE WILL LIKELY BE FREEZING PCPN ACRS THE NW HALF OF THE CWFA...BUT THIS SHOULD BE ON THE LIGHT SIDE. FOR THE SOUTHEAST...LIGHT RAIN IS EXPECTED. MODELS CONTINUE TO SHOW A DRY SLOT WORKING INTO THE REGION BY MID MORNING. THIS MAY CHC PCPN TO DRIZZLE OR FREEZING DRIZZLE. HAVE OPTED TO GO WITH THE LIGHT FREEZING RAIN/LIGHT RAIN WORDING DUE TO LINGER PCPN EARLY IN THE MORNING IN ASSOCIATION WITH THE LOW AND FOR THE FACT THAT SOME OF THE DRIZZLE MAY MEASURE. AS COLDER AIR AND DEEPER ATMOSPHERIC MOISTURE FILTER INTO THE REGION DURING THE AFTERNOON...ANY DRIZZLE WILL CHANGEOVER TO SOME LIGHT SNOW. MAIN LAKE EFFECT EVENT LOOKS TO HOLD OFF UNTIL MONDAY NIGHT AND WILL LEAVE THOSE DETAILS TO THE LONG TERM FORECASTER. && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE MONDAY NIGHT THROUGH TUESDAY... MAIN CONCERN FOR THE LONG TERM TODAY REVOLVES AROUND LAKE EFFECT POTENTIAL AT THE START OF THE PERIOD. MODERATE LOW/MID LEVEL CAA FOLLOWING MAJOR FRONTAL WAVE ON MON WILL BRING MUCH COLDER AIR ACROSS THE LAKE WITH AMPLE LAKE INSTABILITY DEVELOPING. NEAR RECORD WARM LAKE TEMPERATURE OF AROUND 5C PER LATEST SATELLITE DERIVED DATA WILL CONTRIBUTE TO MODERATE COLLIER INDEX WITH LAKE INDUCED CAPE AROUND 500J/KG AND LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET. INSTABILITY IS CERTAINLY MORE THAN AMPLE...HOWEVER MUCH UNCERTAINTY LIES WITH BAND MODE...PLACEMENT...AND AMOUNT OF SHEAR. FROM A PATTERN RECOGNITION PROSPECTIVE...SETUP LOOKS VERY FAVORABLE WITH A 1040+MB HIGH BUILDING SOUTH THROUGH THE PLAINS AND FAVORABLE N/NNW FLOW DEVELOPING DOWN A SUBSTANTIAL FETCH OF LAKE MICHIGAN. A POTENTIAL NEGATIVE...BOTH NAM/GFS SUGGEST THERE WILL BE SOME SHEAR NEAR THE TOP OF THE LAKE INDUCED MIXED LAYER WITH A MORE WESTERLY COMPONENT AT 700MB AND MORE NW/NNW AT 850MB. NAM-WRF PLUME ANALYSIS CONTINUES TO SUGGEST THE POTENTIAL FOR A TYPE I LAKE EFFECT BAND...MEANING A DOMINANT BAND PARALLEL TO THE MAJOR AXIS OF THE LAKE. NAM-WRF HAS BEEN FLIP-FLOPPING WILDLY FROM RUN TO RUN WITH RESPECT TO DIRECTION OF LOW LEVEL FLOW...WITH 00Z AND 06Z RUNS SUGGESTING A NEAR DUE NORTH FETCH...WHILE 12Z RUN SUGGESTS MORE NW FETCH. A LOOK AT SOME OTHER MESOSCALE GUIDANCE SUCH AS THE FSL EXPERIMENTAL RUC AND THE CANADIAN GEM SHOW MORE UNCERTAINTY...WITH BOTH THOSE MODELS DEPICTING MORE NORTHERLY FLOW AND A MORE WESTWARD BAND PLACEMENT. TYPICAL BIAS OF MESOSCALE MODELS ARE TO BE TOO FAR WEST WITH A DOMINANT BAND AT THE SOUTHERN END OF LAKE MICHIGAN. WITH THE VERY POOR MODEL AGREEMENT AND CONSISTENCY...JUST NOT ENOUGH CONFIDENCE ON BAND PLACEMENT OR MODE TO GO WITH AN LES WATCH YET. STILL ENOUGH TIME FOR A SHORTER RANGE WATCH FROM THE MIDNIGHT SHIFT IF MODEL GUIDANCE STARTS TO CONVERGE ON A COMMON SOLUTION. THIS DOES HAVE THE POTENTIAL TO BE A MAJOR EVENT GIVEN STRONG THERMODYNAMICS...BUT ONLY IF A DOMINANT BAND FORMS...AND THAT IS STILL QUITE UNCERTAIN. CP SURFACE HIGH BUILDS ACROSS THE OHIO VALLEY LATER TUE NGT INTO WED WITH CRASHING INVERSION HEIGHTS AND BACKING LOW LEVEL FLOW CUTTING OFF ANY REMAINING LAKE EFFECT. SHOULD SEE A DRY PERIOD FOR WED AND THU WITH A MODERATING TREND AS HEIGHTS RISE IN RESPONSE TO DIGGING UPSTREAM TROUGH. VERY LITTLE CHANGE MADE TO CONTINUITY IN THE LATER PERIODS WITH PRIMARY CONCERNS IN SHORT TERM HIGH IMPACT WEATHER. STILL APPEARS THAT ONE OR SEVERAL CLIPPER TYPE SHORTWAVES WILL CROSS THE GREAT LAKES STARTING AT THE END OF THE WEEK AND HAVE CONTINUED WITH LOW CHANCE POPS...MAINLY ACROSS THE NORTHERN PORTION OF THE CWA. TEMPS WILL AVERAGE AROUND NORMAL FOR MUCH OF THE LONG TERM... BUT THIS WILL FEEL COLD AFTER THE INCREDIBLE STRETCH OF WARM WEATHER THE PAST MONTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR INZ020-INZ022-INZ023- INZ024-INZ025-INZ026-INZ027-INZ032-INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ008-INZ009-INZ012-INZ013-INZ014-INZ015-INZ016-INZ017- INZ018. ICE STORM WARNING UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ003- INZ004-INZ005-INZ006-INZ007. MI...ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OHZ016-OHZ024-OHZ025. FREEZING RAIN ADVISORY UNTIL 12 PM EST MONDAY FOR OHZ004-OHZ005- OHZ015. ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-LMZ046. $$ AVIATION/UPDATE...TAYLOR SHORT TERM...HICKMAN LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 937 PM EST SUN JAN 14 2007 .UPDATE... EVE RAOB/TAMDAR SOUNDINGS SHOWING WARM LAYER OF GENERALLY +2 TO +6C OVER OUR AREA RESULTING IN INITIAL PRECIP REACHING THE GROUND AS RN/ZR. SFC OBS AND CALLS TO POLICE IN THE AREA INDICATE SO FAR ONLY PATCHY REPORTS OF GLAZING IN NRN INDIANA AND NW OH EVEN THOUGH SOME ASOS/AWOS SITES REPORTING TEMPS AT FREEZING. THIS PRBLY A RESULT OF TEMPERATURE OF HEAVY RAINFALL GENERALLY REACHING THE GROUND ABOVE FREEZING. IN MICHIGAN WHERE SFC TEMPS HAVE BEEN RUNNING A DEGREE OR TWO BELOW FREEZING ALL DAY AND THIS EVE, MORE WIDESPREAD GLAZING IS BEING REPORTED. WITH WAA OVERNIGHT AS SFC LOW MOVES NE FROM SRN MO TO WEST CENTRAL OH, THE RN/SN LINE, WHICH IS EXPECTED TO SETUP FROM JUST NORTH OF CHICAGO TO JUST NORTH OF DETROIT THIS EVE, WILL PRBLY SHIFT SLIGHTLY NORTH. THUS, AS IN GOING FCST STILL EXPECTING A MAINLY LIQUID EVENT WITH MAIN THREAT FOR ICE ACCUMULATIONS ACROSS OUR NRN COUNTIES. MAIN QUESTIONS ARE HOW MUCH OF THE HEAVY RAIN WILL ACCUMULATE AS ICE IN THE ADVISORY AREAS AND IF SFC TEMPS WILL FALL SUFFICIENTLY SOUTH OF THE ADVISORY AREA TO WARRANT EXPANSION. FOR NOW FEEL THINGS ARE ON TRACK AND WILL CONTINUE TO MONITOR BUT NO CHANGES TO HEADLINES OR FCSTS PLANNED THIS EVE. && .AVIATION... ONLY MINOR CHANGES TO PREVIOUS TAFS. AREA OF LOW PRESSURE DVLPG OVER SWRN MO THIS EVE WAS CAUSING OVER-RUNNING PRECIP TO DVLP NORTH OF STNRY FRONT ALONG OH RVR. THIS SHOULD SPREAD INTO NRN INDIANA OVER THE NEXT COUPLE OF HOURS WITH HEAVIEST RAINFALL INITIALLY MOVG INTO THE FWA AREA. CIGS/VSBYS WERE ALREADY LOWERING IN ADVANCE OF THE RAINFALL THIS EVE APPARENTLY IN RESPONSE TO DIURNAL COOLING OF THE VERY MOIST LOW LEVELS. TEMPS EXPECTED TO REMAIN JUST COLD ENOUGH FOR FREEZING RAIN AT SBN AND JUST WARM ENOUGH FOR RAIN NOT TO FREEZE AT FWA AS THE LOW MOVES NE ACROSS SRN INDIANA TONIGHT. PRECIP INTENSITY SHOULD DIMINISH ON MONDAY AS MID LEVEL DRY SLOT MOVES OVER THE AREA. WITH COLD AIR WRAPPING AROUND THE LOW AS IT DEPARTS THE AREA TO OUR EAST ON MONDAY, PRECIP SHOULD CHANGE OVER TO SNOW AT SBN EARLY IN THE AFTN. POTENTIAL FOR LAKE ENHANCEMENT TO INTENSIFY SNOWFALL LATE AFTN BUT SINCE NEAR END OF TAF PD DID NOT ADD TO TAFS YET. LIKEWISE AT FWA COLDER AIR FILLING IN BEHIND THE LOW COULD CHANGE PRECIP TO -ZL OR -SN LATE IN THE AFTN BUT HELD OFF MENTIONING THIS CHANGE IN THE TAF FOR NOW. && .SHORT TERM... TONIGHT AND MONDAY. ...SIGNIFICANT ICING EXPECTED ACROSS SOUTHERN LOWER MICHIGAN TONIGHT INTO MONDAY MORNING... ...SOME ICING EXPECTED ACROSS NORTHERN INDIANA AND NORTHWEST OHIO TONIGHT AND MONDAY... 12Z NAM-WRF AND 12Z GFS CONTINUE TO TREND NEXT WAVE OF LOW PRESSURE FARTHER NORTHWEST. THE NAM-WRF IS THE FARTHEST NORTHWEST OF THE TWO...PLACING THE WAVE OF LOW PRESSURE OVER NW OHIO BY 12Z MONDAY. BASED ON THE TREND OF BRINGING THE LOW FARTHER NORTHWEST...FEEL MORE INCLINED TO SIDE WITH THE NAM-WRF AND THUS WILL USE ITS SOLUTION AS A BACKBONE TO THE SHORT TERM FORECAST. ITS WARMER THERMAL PROFILE WILL RESULT IN MOSTLY FREEZING RAIN TONIGHT ACRS THE NRN CWFA. AT 20Z...LOW PRESSURE WAS DEVELOPING ALONG A STATIONARY FRONT OVER NW ARKANSAS. AS A STRONG S/WV AND JET PIVOT NORTHEAST INTO THE CNTRL PLAINS TONIGHT AND THEN INTO THE WRN GREAT LAKES ON MONDAY...THE LOW WILL MOVE NORTHEAST AND DEEPEN WITH TIME...BEING LOCATED NEAR SW INDIANA AT 06Z MONDAY AND NEAR NW OHIO BY 12Z MONDAY. THE LOW WILL BE ASSOCIATED WITH STRONG...MOIST LOW LVL WARM ADVECTION. THIS STRONG ASCENT WILL TEAM UP WITH UPR LVL DIVERGENCE FROM A STRONG JET ALOFT. THIS WILL RESULT IN WIDESPREAD PCPN ACRS THE CWFA OVERNIGHT. IN FACT...LATEST MOSAIC RADAR WAS SHOWING A LARGE AREA OF PCPN BLOSSOMING ACRS THE CNTRL AND SRN PLAINS. THIS PCPN WILL CONTINUE TO EXPAND AND MOVE NE INTO THE REGION TONIGHT. THERE IS A LOT TO BE CONCERNED ABOUT OVERNIGHT INTO THE FIRST PART OF MONDAY AS COLD AIR REMAINS TRAPPED NEAR THE SFC ACRS THE FAR NRN CWFA. LATEST OBSERVATIONS SHOW TEMPS HOVERING BETWEEN 30 AND 33 DEGREES ACRS FAR NRN INDIANA...SOUTHERN LOWER MICHIGAN AND FAR NORTHWEST OHIO. THESE TEMPS WILL NOT BUDGE MUCH OVERNIGHT...AND MAY SLIGHTLY DROP A DEGREE OR TWO. FOR THE REMAINDER OF THE REGION...TEMPS WILL REMAIN STEADY STATE IN THE LOWER TO MID 30S...EXPECT FOR THE FAR SOUTHEAST WHERE WARMER AIR WILL BE PULLED WESTWARD AS THE LOW APPROACHES. WITH ABOUT THREE QUARTERS TO AROUND ONE INCH OF QPF EXPECTED OVERNIGHT...SIGNIFICANT ICING WILL OCCUR ACRS THE MICHIGAN COUNTIES WHERE ABOUT A HALF INCH OF ICE ACCUMULATION IS EXPECTED. FOR THE FAR NRN INDIANA AND NORTHWEST OHIO COUNTIES...ICE ACCUMULATIONS WILL BE LESS THAN A QUARTER INCH. FARTHER SOUTH...MAINLY RAIN IS EXPECTED. AN ICE STORM WARNING WILL BE ISSUED FOR THE MICHIGAN COUNTIES UNTIL 17Z MONDAY...WHILE A FREEZING RAIN ADVISORY WILL BE ISSUED FOR THE FAR NRN INDIANA/NW OHIO COUNTIES THROUGH 17Z MONDAY. ADDITIONAL RAINFALL ACRS THE FAR SOUTH/SOUTHEAST WILL LIKELY LEAD TO RIVER FLOODING ALONG THE UPPER WABASH AND MAUMEE RIVER BASINS..SO WILL MAINTAIN FLOOD WATCH FOR THIS LOCATION THROUGH 18Z MONDAY. ON MONDAY...AS SFC LOW PRESSURE PULLS AWAY TO THE NE...COLDER AIR WILL BEGIN TO FILTER SE INTO THE FCST AREA. THERE WILL LIKELY BE FREEZING PCPN ACRS THE NW HALF OF THE CWFA...BUT THIS SHOULD BE ON THE LIGHT SIDE. FOR THE SOUTHEAST...LIGHT RAIN IS EXPECTED. MODELS CONTINUE TO SHOW A DRY SLOT WORKING INTO THE REGION BY MID MORNING. THIS MAY CHC PCPN TO DRIZZLE OR FREEZING DRIZZLE. HAVE OPTED TO GO WITH THE LIGHT FREEZING RAIN/LIGHT RAIN WORDING DUE TO LINGER PCPN EARLY IN THE MORNING IN ASSOCIATION WITH THE LOW AND FOR THE FACT THAT SOME OF THE DRIZZLE MAY MEASURE. AS COLDER AIR AND DEEPER ATMOSPHERIC MOISTURE FILTER INTO THE REGION DURING THE AFTERNOON...ANY DRIZZLE WILL CHANGEOVER TO SOME LIGHT SNOW. MAIN LAKE EFFECT EVENT LOOKS TO HOLD OFF UNTIL MONDAY NIGHT AND WILL LEAVE THOSE DETAILS TO THE LONG TERM FORECASTER. && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE MONDAY NIGHT THROUGH TUESDAY... MAIN CONCERN FOR THE LONG TERM TODAY REVOLVES AROUND LAKE EFFECT POTENTIAL AT THE START OF THE PERIOD. MODERATE LOW/MID LEVEL CAA FOLLOWING MAJOR FRONTAL WAVE ON MON WILL BRING MUCH COLDER AIR ACROSS THE LAKE WITH AMPLE LAKE INSTABILITY DEVELOPING. NEAR RECORD WARM LAKE TEMPERATURE OF AROUND 5C PER LATEST SATELLITE DERIVED DATA WILL CONTRIBUTE TO MODERATE COLLIER INDEX WITH LAKE INDUCED CAPE AROUND 500J/KG AND LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET. INSTABILITY IS CERTAINLY MORE THAN AMPLE...HOWEVER MUCH UNCERTAINTY LIES WITH BAND MODE...PLACEMENT...AND AMOUNT OF SHEAR. FROM A PATTERN RECOGNITION PROSPECTIVE...SETUP LOOKS VERY FAVORABLE WITH A 1040+MB HIGH BUILDING SOUTH THROUGH THE PLAINS AND FAVORABLE N/NNW FLOW DEVELOPING DOWN A SUBSTANTIAL FETCH OF LAKE MICHIGAN. A POTENTIAL NEGATIVE...BOTH NAM/GFS SUGGEST THERE WILL BE SOME SHEAR NEAR THE TOP OF THE LAKE INDUCED MIXED LAYER WITH A MORE WESTERLY COMPONENT AT 700MB AND MORE NW/NNW AT 850MB. NAM-WRF PLUME ANALYSIS CONTINUES TO SUGGEST THE POTENTIAL FOR A TYPE I LAKE EFFECT BAND...MEANING A DOMINANT BAND PARALLEL TO THE MAJOR AXIS OF THE LAKE. NAM-WRF HAS BEEN FLIP-FLOPPING WILDLY FROM RUN TO RUN WITH RESPECT TO DIRECTION OF LOW LEVEL FLOW...WITH 00Z AND 06Z RUNS SUGGESTING A NEAR DUE NORTH FETCH...WHILE 12Z RUN SUGGESTS MORE NW FETCH. A LOOK AT SOME OTHER MESOSCALE GUIDANCE SUCH AS THE FSL EXPERIMENTAL RUC AND THE CANADIAN GEM SHOW MORE UNCERTAINTY...WITH BOTH THOSE MODELS DEPICTING MORE NORTHERLY FLOW AND A MORE WESTWARD BAND PLACEMENT. TYPICAL BIAS OF MESOSCALE MODELS ARE TO BE TOO FAR WEST WITH A DOMINANT BAND AT THE SOUTHERN END OF LAKE MICHIGAN. WITH THE VERY POOR MODEL AGREEMENT AND CONSISTENCY...JUST NOT ENOUGH CONFIDENCE ON BAND PLACEMENT OR MODE TO GO WITH AN LES WATCH YET. STILL ENOUGH TIME FOR A SHORTER RANGE WATCH FROM THE MIDNIGHT SHIFT IF MODEL GUIDANCE STARTS TO CONVERGE ON A COMMON SOLUTION. THIS DOES HAVE THE POTENTIAL TO BE A MAJOR EVENT GIVEN STRONG THERMODYNAMICS...BUT ONLY IF A DOMINANT BAND FORMS...AND THAT IS STILL QUITE UNCERTAIN. CP SURFACE HIGH BUILDS ACROSS THE OHIO VALLEY LATER TUE NGT INTO WED WITH CRASHING INVERSION HEIGHTS AND BACKING LOW LEVEL FLOW CUTTING OFF ANY REMAINING LAKE EFFECT. SHOULD SEE A DRY PERIOD FOR WED AND THU WITH A MODERATING TREND AS HEIGHTS RISE IN RESPONSE TO DIGGING UPSTREAM TROUGH. VERY LITTLE CHANGE MADE TO CONTINUITY IN THE LATER PERIODS WITH PRIMARY CONCERNS IN SHORT TERM HIGH IMPACT WEATHER. STILL APPEARS THAT ONE OR SEVERAL CLIPPER TYPE SHORTWAVES WILL CROSS THE GREAT LAKES STARTING AT THE END OF THE WEEK AND HAVE CONTINUED WITH LOW CHANCE POPS...MAINLY ACROSS THE NORTHERN PORTION OF THE CWA. TEMPS WILL AVERAGE AROUND NORMAL FOR MUCH OF THE LONG TERM... BUT THIS WILL FEEL COLD AFTER THE INCREDIBLE STRETCH OF WARM WEATHER THE PAST MONTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR INZ020-INZ022-INZ023-INZ024-INZ025-INZ026-INZ027-INZ032- INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ003-INZ004-INZ005-INZ006-INZ007. MI...ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR OHZ016-OHZ024-OHZ025. FREEZING RAIN ADVISORY UNTIL 12 PM EST MONDAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY FROM MIDNIGHT EST UNTIL 5PM EST TUESDAY FOR LMZ043-LMZ046. && $$ AVIATION/UPDATE...TAYLOR SHORT TERM...HICKMAN LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 627 PM EST SUN JAN 14 2007 .AVIATION... ONLY MINOR CHANGES TO PREVIOUS TAFS. AREA OF LOW PRESSURE DVLPG OVER SWRN MO THIS EVE WAS CAUSING OVER-RUNNING PRECIP TO DVLP NORTH OF STNRY FRONT ALONG OH RVR. THIS SHOULD SPREAD INTO NRN INDIANA OVER THE NEXT COUPLE OF HOURS WITH HEAVIEST RAINFALL INITIALLY MOVG INTO THE FWA AREA. CIGS/VSBYS WERE ALREADY LOWERING IN ADVANCE OF THE RAINFALL THIS EVE APPARENTLY IN RESPONSE TO DIURNAL COOLING OF THE VERY MOIST LOW LEVELS. TEMPS EXPECTED TO REMAIN JUST COLD ENOUGH FOR FREEZING RAIN AT SBN AND JUST WARM ENOUGH FOR RAIN NOT TO FREEZE AT FWA AS THE LOW MOVES NE ACROSS SRN INDIANA TONIGHT. PRECIP INTENSITY SHOULD DIMINISH ON MONDAY AS MID LEVEL DRY SLOT MOVES OVER THE AREA. WITH COLD AIR WRAPPING AROUND THE LOW AS IT DEPARTS THE AREA TO OUR EAST ON MONDAY, PRECIP SHOULD CHANGE OVER TO SNOW AT SBN EARLY IN THE AFTN. POTENTIAL FOR LAKE ENHANCEMENT TO INTENSIFY SNOWFALL LATE AFTN BUT SINCE NEAR END OF TAF PD DID NOT ADD TO TAFS YET. LIKEWISE AT FWA COLDER AIR FILLING IN BEHIND THE LOW COULD CHANGE PRECIP TO -ZL OR -SN LATE IN THE AFTN BUT HELD OFF MENTIONING THIS CHANGE IN THE TAF FOR NOW. && .SHORT TERM... TONIGHT AND MONDAY. ...SIGNIFICANT ICING EXPECTED ACROSS SOUTHERN LOWER MICHIGAN TONIGHT INTO MONDAY MORNING... ...SOME ICING EXPECTED ACROSS NORTHERN INDIANA AND NORTHWEST OHIO TONIGHT AND MONDAY... 12Z NAM-WRF AND 12Z GFS CONTINUE TO TREND NEXT WAVE OF LOW PRESSURE FARTHER NORTHWEST. THE NAM-WRF IS THE FARTHEST NORTHWEST OF THE TWO...PLACING THE WAVE OF LOW PRESSURE OVER NW OHIO BY 12Z MONDAY. BASED ON THE TREND OF BRINGING THE LOW FARTHER NORTHWEST...FEEL MORE INCLINED TO SIDE WITH THE NAM-WRF AND THUS WILL USE ITS SOLUTION AS A BACKBONE TO THE SHORT TERM FORECAST. ITS WARMER THERMAL PROFILE WILL RESULT IN MOSTLY FREEZING RAIN TONIGHT ACRS THE NRN CWFA. AT 20Z...LOW PRESSURE WAS DEVELOPING ALONG A STATIONARY FRONT OVER NW ARKANSAS. AS A STRONG S/WV AND JET PIVOT NORTHEAST INTO THE CNTRL PLAINS TONIGHT AND THEN INTO THE WRN GREAT LAKES ON MONDAY...THE LOW WILL MOVE NORTHEAST AND DEEPEN WITH TIME...BEING LOCATED NEAR SW INDIANA AT 06Z MONDAY AND NEAR NW OHIO BY 12Z MONDAY. THE LOW WILL BE ASSOCIATED WITH STRONG...MOIST LOW LVL WARM ADVECTION. THIS STRONG ASCENT WILL TEAM UP WITH UPR LVL DIVERGENCE FROM A STRONG JET ALOFT. THIS WILL RESULT IN WIDESPREAD PCPN ACRS THE CWFA OVERNIGHT. IN FACT...LATEST MOSAIC RADAR WAS SHOWING A LARGE AREA OF PCPN BLOSSOMING ACRS THE CNTRL AND SRN PLAINS. THIS PCPN WILL CONTINUE TO EXPAND AND MOVE NE INTO THE REGION TONIGHT. THERE IS A LOT TO BE CONCERNED ABOUT OVERNIGHT INTO THE FIRST PART OF MONDAY AS COLD AIR REMAINS TRAPPED NEAR THE SFC ACRS THE FAR NRN CWFA. LATEST OBSERVATIONS SHOW TEMPS HOVERING BETWEEN 30 AND 33 DEGREES ACRS FAR NRN INDIANA...SOUTHERN LOWER MICHIGAN AND FAR NORTHWEST OHIO. THESE TEMPS WILL NOT BUDGE MUCH OVERNIGHT...AND MAY SLIGHTLY DROP A DEGREE OR TWO. FOR THE REMAINDER OF THE REGION...TEMPS WILL REMAIN STEADY STATE IN THE LOWER TO MID 30S...EXPECT FOR THE FAR SOUTHEAST WHERE WARMER AIR WILL BE PULLED WESTWARD AS THE LOW APPROACHES. WITH ABOUT THREE QUARTERS TO AROUND ONE INCH OF QPF EXPECTED OVERNIGHT...SIGNIFICANT ICING WILL OCCUR ACRS THE MICHIGAN COUNTIES WHERE ABOUT A HALF INCH OF ICE ACCUMULATION IS EXPECTED. FOR THE FAR NRN INDIANA AND NORTHWEST OHIO COUNTIES...ICE ACCUMULATIONS WILL BE LESS THAN A QUARTER INCH. FARTHER SOUTH...MAINLY RAIN IS EXPECTED. AN ICE STORM WARNING WILL BE ISSUED FOR THE MICHIGAN COUNTIES UNTIL 17Z MONDAY...WHILE A FREEZING RAIN ADVISORY WILL BE ISSUED FOR THE FAR NRN INDIANA/NW OHIO COUNTIES THROUGH 17Z MONDAY. ADDITIONAL RAINFALL ACRS THE FAR SOUTH/SOUTHEAST WILL LIKELY LEAD TO RIVER FLOODING ALONG THE UPPER WABASH AND MAUMEE RIVER BASINS..SO WILL MAINTAIN FLOOD WATCH FOR THIS LOCATION THROUGH 18Z MONDAY. ON MONDAY...AS SFC LOW PRESSURE PULLS AWAY TO THE NE...COLDER AIR WILL BEGIN TO FILTER SE INTO THE FCST AREA. THERE WILL LIKELY BE FREEZING PCPN ACRS THE NW HALF OF THE CWFA...BUT THIS SHOULD BE ON THE LIGHT SIDE. FOR THE SOUTHEAST...LIGHT RAIN IS EXPECTED. MODELS CONTINUE TO SHOW A DRY SLOT WORKING INTO THE REGION BY MID MORNING. THIS MAY CHC PCPN TO DRIZZLE OR FREEZING DRIZZLE. HAVE OPTED TO GO WITH THE LIGHT FREEZING RAIN/LIGHT RAIN WORDING DUE TO LINGER PCPN EARLY IN THE MORNING IN ASSOCIATION WITH THE LOW AND FOR THE FACT THAT SOME OF THE DRIZZLE MAY MEASURE. AS COLDER AIR AND DEEPER ATMOSPHERIC MOISTURE FILTER INTO THE REGION DURING THE AFTERNOON...ANY DRIZZLE WILL CHANGEOVER TO SOME LIGHT SNOW. MAIN LAKE EFFECT EVENT LOOKS TO HOLD OFF UNTIL MONDAY NIGHT AND WILL LEAVE THOSE DETAILS TO THE LONG TERM FORECASTER. && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE MONDAY NIGHT THROUGH TUESDAY... MAIN CONCERN FOR THE LONG TERM TODAY REVOLVES AROUND LAKE EFFECT POTENTIAL AT THE START OF THE PERIOD. MODERATE LOW/MID LEVEL CAA FOLLOWING MAJOR FRONTAL WAVE ON MON WILL BRING MUCH COLDER AIR ACROSS THE LAKE WITH AMPLE LAKE INSTABILITY DEVELOPING. NEAR RECORD WARM LAKE TEMPERATURE OF AROUND 5C PER LATEST SATELLITE DERIVED DATA WILL CONTRIBUTE TO MODERATE COLLIER INDEX WITH LAKE INDUCED CAPE AROUND 500J/KG AND LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET. INSTABILITY IS CERTAINLY MORE THAN AMPLE...HOWEVER MUCH UNCERTAINTY LIES WITH BAND MODE...PLACEMENT...AND AMOUNT OF SHEAR. FROM A PATTERN RECOGNITION PROSPECTIVE...SETUP LOOKS VERY FAVORABLE WITH A 1040+MB HIGH BUILDING SOUTH THROUGH THE PLAINS AND FAVORABLE N/NNW FLOW DEVELOPING DOWN A SUBSTANTIAL FETCH OF LAKE MICHIGAN. A POTENTIAL NEGATIVE...BOTH NAM/GFS SUGGEST THERE WILL BE SOME SHEAR NEAR THE TOP OF THE LAKE INDUCED MIXED LAYER WITH A MORE WESTERLY COMPONENT AT 700MB AND MORE NW/NNW AT 850MB. NAM-WRF PLUME ANALYSIS CONTINUES TO SUGGEST THE POTENTIAL FOR A TYPE I LAKE EFFECT BAND...MEANING A DOMINANT BAND PARALLEL TO THE MAJOR AXIS OF THE LAKE. NAM-WRF HAS BEEN FLIP-FLOPPING WILDLY FROM RUN TO RUN WITH RESPECT TO DIRECTION OF LOW LEVEL FLOW...WITH 00Z AND 06Z RUNS SUGGESTING A NEAR DUE NORTH FETCH...WHILE 12Z RUN SUGGESTS MORE NW FETCH. A LOOK AT SOME OTHER MESOSCALE GUIDANCE SUCH AS THE FSL EXPERIMENTAL RUC AND THE CANADIAN GEM SHOW MORE UNCERTAINTY...WITH BOTH THOSE MODELS DEPICTING MORE NORTHERLY FLOW AND A MORE WESTWARD BAND PLACEMENT. TYPICAL BIAS OF MESOSCALE MODELS ARE TO BE TOO FAR WEST WITH A DOMINANT BAND AT THE SOUTHERN END OF LAKE MICHIGAN. WITH THE VERY POOR MODEL AGREEMENT AND CONSISTENCY...JUST NOT ENOUGH CONFIDENCE ON BAND PLACEMENT OR MODE TO GO WITH AN LES WATCH YET. STILL ENOUGH TIME FOR A SHORTER RANGE WATCH FROM THE MIDNIGHT SHIFT IF MODEL GUIDANCE STARTS TO CONVERGE ON A COMMON SOLUTION. THIS DOES HAVE THE POTENTIAL TO BE A MAJOR EVENT GIVEN STRONG THERMODYNAMICS...BUT ONLY IF A DOMINANT BAND FORMS...AND THAT IS STILL QUITE UNCERTAIN. CP SURFACE HIGH BUILDS ACROSS THE OHIO VALLEY LATER TUE NGT INTO WED WITH CRASHING INVERSION HEIGHTS AND BACKING LOW LEVEL FLOW CUTTING OFF ANY REMAINING LAKE EFFECT. SHOULD SEE A DRY PERIOD FOR WED AND THU WITH A MODERATING TREND AS HEIGHTS RISE IN RESPONSE TO DIGGING UPSTREAM TROUGH. VERY LITTLE CHANGE MADE TO CONTINUITY IN THE LATER PERIODS WITH PRIMARY CONCERNS IN SHORT TERM HIGH IMPACT WEATHER. STILL APPEARS THAT ONE OR SEVERAL CLIPPER TYPE SHORTWAVES WILL CROSS THE GREAT LAKES STARTING AT THE END OF THE WEEK AND HAVE CONTINUED WITH LOW CHANCE POPS...MAINLY ACROSS THE NORTHERN PORTION OF THE CWA. TEMPS WILL AVERAGE AROUND NORMAL FOR MUCH OF THE LONG TERM... BUT THIS WILL FEEL COLD AFTER THE INCREDIBLE STRETCH OF WARM WEATHER THE PAST MONTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR INZ020-INZ022-INZ023-INZ024-INZ025-INZ026-INZ027-INZ032- INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ003-INZ004-INZ005-INZ006-INZ007. MI...ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR OHZ016-OHZ024-OHZ025. FREEZING RAIN ADVISORY UNTIL 12 PM EST MONDAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY FROM MIDNIGHT EST UNTIL 5PM EST TUESDAY FOR LMZ043-LMZ046. && $$ AVIATION...TAYLOR SHORT TERM...HICKMAN LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 357 PM EST SUN JAN 14 2007 .SHORT TERM... TONIGHT AND MONDAY. ...SIGNIFICANT ICING EXPECTED ACROSS SOUTHERN LOWER MICHIGAN TONIGHT INTO MONDAY MORNING... ...SOME ICING EXPECTED ACROSS NORTHERN INDIANA AND NORTHWEST OHIO TONIGHT AND MONDAY... 12Z NAM-WRF AND 12Z GFS CONTINUE TO TREND NEXT WAVE OF LOW PRESSURE FARTHER NORTHWEST. THE NAM-WRF IS THE FARTHEST NORTHWEST OF THE TWO...PLACING THE WAVE OF LOW PRESSURE OVER NW OHIO BY 12Z MONDAY. BASED ON THE TREND OF BRINGING THE LOW FARTHER NORTHWEST...FEEL MORE INCLINED TO SIDE WITH THE NAM-WRF AND THUS WILL USE ITS SOLUTION AS A BACKBONE TO THE SHORT TERM FORECAST. ITS WARMER THERMAL PROFILE WILL RESULT IN MOSTLY FREEZING RAIN TONIGHT ACRS THE NRN CWFA. AT 20Z...LOW PRESSURE WAS DEVELOPING ALONG A STATIONARY FRONT OVER NW ARKANSAS. AS A STRONG S/WV AND JET PIVOT NORTHEAST INTO THE CNTRL PLAINS TONIGHT AND THEN INTO THE WRN GREAT LAKES ON MONDAY...THE LOW WILL MOVE NORTHEAST AND DEEPEN WITH TIME...BEING LOCATED NEAR SW INDIANA AT 06Z MONDAY AND NEAR NW OHIO BY 12Z MONDAY. THE LOW WILL BE ASSOCIATED WITH STRONG...MOIST LOW LVL WARM ADVECTION. THIS STRONG ASCENT WILL TEAM UP WITH UPR LVL DIVERGENCE FROM A STRONG JET ALOFT. THIS WILL RESULT IN WIDESPREAD PCPN ACRS THE CWFA OVERNIGHT. IN FACT...LATEST MOSAIC RADAR WAS SHOWING A LARGE AREA OF PCPN BLOSSOMING ACRS THE CNTRL AND SRN PLAINS. THIS PCPN WILL CONTINUE TO EXPAND AND MOVE NE INTO THE REGION TONIGHT. THERE IS A LOT TO BE CONCERNED ABOUT OVERNIGHT INTO THE FIRST PART OF MONDAY AS COLD AIR REMAINS TRAPPED NEAR THE SFC ACRS THE FAR NRN CWFA. LATEST OBSERVATIONS SHOW TEMPS HOVERING BETWEEN 30 AND 33 DEGREES ACRS FAR NRN INDIANA...SOUTHERN LOWER MICHIGAN AND FAR NORTHWEST OHIO. THESE TEMPS WILL NOT BUDGE MUCH OVERNIGHT...AND MAY SLIGHTLY DROP A DEGREE OR TWO. FOR THE REMAINDER OF THE REGION...TEMPS WILL REMAIN STEADY STATE IN THE LOWER TO MID 30S...EXPECT FOR THE FAR SOUTHEAST WHERE WARMER AIR WILL BE PULLED WESTWARD AS THE LOW APPROACHES. WITH ABOUT THREE QUARTERS TO AROUND ONE INCH OF QPF EXPECTED OVERNIGHT...SIGNIFICANT ICING WILL OCCUR ACRS THE MICHIGAN COUNTIES WHERE ABOUT A HALF INCH OF ICE ACCUMULATION IS EXPECTED. FOR THE FAR NRN INDIANA AND NORTHWEST OHIO COUNTIES...ICE ACCUMULATIONS WILL BE LESS THAN A QUARTER INCH. FARTHER SOUTH...MAINLY RAIN IS EXPECTED. AN ICE STORM WARNING WILL BE ISSUED FOR THE MICHIGAN COUNTIES UNTIL 17Z MONDAY...WHILE A FREEZING RAIN ADVISORY WILL BE ISSUED FOR THE FAR NRN INDIANA/NW OHIO COUNTIES THROUGH 17Z MONDAY. ADDITIONAL RAINFALL ACRS THE FAR SOUTH/SOUTHEAST WILL LIKELY LEAD TO RIVER FLOODING ALONG THE UPPER WABASH AND MAUMEE RIVER BASINS..SO WILL MAINTAIN FLOOD WATCH FOR THIS LOCATION THROUGH 18Z MONDAY. ON MONDAY...AS SFC LOW PRESSURE PULLS AWAY TO THE NE...COLDER AIR WILL BEGIN TO FILTER SE INTO THE FCST AREA. THERE WILL LIKELY BE FREEZING PCPN ACRS THE NW HALF OF THE CWFA...BUT THIS SHOULD BE ON THE LIGHT SIDE. FOR THE SOUTHEAST...LIGHT RAIN IS EXPECTED. MODELS CONTINUE TO SHOW A DRY SLOT WORKING INTO THE REGION BY MID MORNING. THIS MAY CHC PCPN TO DRIZZLE OR FREEZING DRIZZLE. HAVE OPTED TO GO WITH THE LIGHT FREEZING RAIN/LIGHT RAIN WORDING DUE TO LINGER PCPN EARLY IN THE MORNING IN ASSOCIATION WITH THE LOW AND FOR THE FACT THAT SOME OF THE DRIZZLE MAY MEASURE. AS COLDER AIR AND DEEPER ATMOSPHERIC MOISTURE FILTER INTO THE REGION DURING THE AFTERNOON...ANY DRIZZLE WILL CHANGEOVER TO SOME LIGHT SNOW. MAIN LAKE EFFECT EVENT LOOKS TO HOLD OFF UNTIL MONDAY NIGHT AND WILL LEAVE THOSE DETAILS TO THE LONG TERM FORECASTER. && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY ...SIGNIFICANT LAKE EFFECT SNOW POSSIBLE MONDAY NIGHT THROUGH TUESDAY... MAIN CONCERN FOR THE LONG TERM TODAY REVOLVES AROUND LAKE EFFECT POTENTIAL AT THE START OF THE PERIOD. MODERATE LOW/MID LEVEL CAA FOLLOWING MAJOR FRONTAL WAVE ON MON WILL BRING MUCH COLDER AIR ACROSS THE LAKE WITH AMPLE LAKE INSTABILITY DEVELOPING. NEAR RECORD WARM LAKE TEMPERATURE OF AROUND 5C PER LATEST SATELLITE DERIVED DATA WILL CONTRIBUTE TO MODERATE COLLIER INDEX WITH LAKE INDUCED CAPE AROUND 500J/KG AND LAKE INDUCED EQUILIBRIUM LEVELS AROUND 10K FEET. INSTABILITY IS CERTAINLY MORE THAN AMPLE...HOWEVER MUCH UNCERTAINTY LIES WITH BAND MODE...PLACEMENT...AND AMOUNT OF SHEAR. FROM A PATTERN RECOGNITION PROSPECTIVE...SETUP LOOKS VERY FAVORABLE WITH A 1040+MB HIGH BUILDING SOUTH THROUGH THE PLAINS AND FAVORABLE N/NNW FLOW DEVELOPING DOWN A SUBSTANTIAL FETCH OF LAKE MICHIGAN. A POTENTIAL NEGATIVE...BOTH NAM/GFS SUGGEST THERE WILL BE SOME SHEAR NEAR THE TOP OF THE LAKE INDUCED MIXED LAYER WITH A MORE WESTERLY COMPONENT AT 700MB AND MORE NW/NNW AT 850MB. NAM-WRF PLUME ANALYSIS CONTINUES TO SUGGEST THE POTENTIAL FOR A TYPE I LAKE EFFECT BAND...MEANING A DOMINANT BAND PARALLEL TO THE MAJOR AXIS OF THE LAKE. NAM-WRF HAS BEEN FLIP-FLOPPING WILDLY FROM RUN TO RUN WITH RESPECT TO DIRECTION OF LOW LEVEL FLOW...WITH 00Z AND 06Z RUNS SUGGESTING A NEAR DUE NORTH FETCH...WHILE 12Z RUN SUGGESTS MORE NW FETCH. A LOOK AT SOME OTHER MESOSCALE GUIDANCE SUCH AS THE FSL EXPERIMENTAL RUC AND THE CANADIAN GEM SHOW MORE UNCERTAINTY...WITH BOTH THOSE MODELS DEPICTING MORE NORTHERLY FLOW AND A MORE WESTWARD BAND PLACEMENT. TYPICAL BIAS OF MESOSCALE MODELS ARE TO BE TOO FAR WEST WITH A DOMINANT BAND AT THE SOUTHERN END OF LAKE MICHIGAN. WITH THE VERY POOR MODEL AGREEMENT AND CONSISTENCY...JUST NOT ENOUGH CONFIDENCE ON BAND PLACEMENT OR MODE TO GO WITH AN LES WATCH YET. STILL ENOUGH TIME FOR A SHORTER RANGE WATCH FROM THE MIDNIGHT SHIFT IF MODEL GUIDANCE STARTS TO CONVERGE ON A COMMON SOLUTION. THIS DOES HAVE THE POTENTIAL TO BE A MAJOR EVENT GIVEN STRONG THERMODYNAMICS...BUT ONLY IF A DOMINANT BAND FORMS...AND THAT IS STILL QUITE UNCERTAIN. CP SURFACE HIGH BUILDS ACROSS THE OHIO VALLEY LATER TUE NGT INTO WED WITH CRASHING INVERSION HEIGHTS AND BACKING LOW LEVEL FLOW CUTTING OFF ANY REMAINING LAKE EFFECT. SHOULD SEE A DRY PERIOD FOR WED AND THU WITH A MODERATING TREND AS HEIGHTS RISE IN RESPONSE TO DIGGING UPSTREAM TROUGH. VERY LITTLE CHANGE MADE TO CONTINUITY IN THE LATER PERIODS WITH PRIMARY CONCERNS IN SHORT TERM HIGH IMPACT WEATHER. STILL APPEARS THAT ONE OR SEVERAL CLIPPER TYPE SHORTWAVES WILL CROSS THE GREAT LAKES STARTING AT THE END OF THE WEEK AND HAVE CONTINUED WITH LOW CHANCE POPS...MAINLY ACROSS THE NORTHERN PORTION OF THE CWA. TEMPS WILL AVERAGE AROUND NORMAL FOR MUCH OF THE LONG TERM... BUT THIS WILL FEEL COLD AFTER THE INCREDIBLE STRETCH OF WARM WEATHER THE PAST MONTH. && .AVIATION... LOW PRESSURE DEVELOPING IN THE LOWER MS RIVER VLY THIS AFTN WILL MOVE NORTHEAST INTO THE MIDDLE OHIO VALLEY BY 06Z...AND ACRS NORTHWEST OHIO BY 12Z. WITH DECENT UPR LVL DIVERGENCE PROVIDED BY A STRONG JET...AND INCREASING STRONG LOW LVL MOIST ASCENT...PCPN WILL ONCE AGAIN BECOME WIDESPREAD ACROSS THE FCST AREA AFTER 02Z MONDAY. IT SHOULD REMAIN COLD ENOUGH AT THE SFC AT THE KSBN TERMINAL TO KEEP PCPN AS FZRA. TEMPS WILL REMAIN ABOVE FREEZING AT KFWA...SO ONLY RAIN IS EXPECTED THERE FOR THE OVERNIGHT HOURS. PCPN WILL TRANSITION OVER TO SOME -DZ OR -FZDZ AFTER 12Z AS DRY SLOT MOVES ACROSS THE REGION...CAUSING A LACK OF ICE NUCLEATION. CIGS WILL REMAIN IN THE IFR CATEGORY THROUGH THIS EVENING...THEN DROP TO LIFR OVERNIGHT. VSBYS WILL DETERIORATE TO IFR OVERNIGHT AS MODERATE PCPN IS EXPECTED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR INZ020-INZ022-INZ023-INZ024-INZ025-INZ026-INZ027-INZ032- INZ033-INZ034. FREEZING RAIN ADVISORY UNTIL 12 PM EST /11 AM CST/ MONDAY FOR INZ003-INZ004-INZ005-INZ006-INZ007. MI...ICE STORM WARNING UNTIL 12 PM EST MONDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY AFTERNOON FOR OHZ016-OHZ024-OHZ025. FREEZING RAIN ADVISORY UNTIL 12 PM EST MONDAY FOR OHZ001-OHZ002. LM...SMALL CRAFT ADVISORY FROM MIDNIGHT EST UNTIL 7PM EST TUESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...HICKMAN LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 926 PM CST SUN JAN 14 2007 .UPDATE.../TONIGHT/ LARGE AREA OF PCPN ASSOCIATED WITH WARM CONVEYOR BELT AND ISENTROPIC LIFT HAS SHIFTED TO THE EAST OF THE CWA. HOWEVER...LARGE DEFORMATION AREA WL CROSS THE STATE OVERNIGHT WITH LIGHT TO OCCASIONALLY MODERATE SNOW PERSISTING THROUGH DAYBREAK. THIS WL PRODUCE ANOTHER INCH OR TWO OF SNOW IN MOST LOCATIONS AND WL LEAVE ALL HEADLINES INTACT FOR NOW. HOWEVER...HAVE LOWERED OVERALL AMOUNTS SLIGHTLY AS AMOUNTS ARE COMING ON THE LOW END AT THIS POINT. OTHERWISE...GRADIENT STILL TIGHTENS OVERNIGHT AND DO EXPECT SOME WIND ISSUES AFTER MIDNIGHT AND ESPECIALLY TOWARD DAYBREAK. COGIL && .SHORT TERM /MONDAY-TUES NIGHT/... ONGOING WINTER STORM THE MAIN FOCUS TODAY. UPDATED HEADLINES ARE OUT. IN SUMMARY...UPGRADED SNOW AND BLOWING SNOW ADVISORY IN NORTHERN IOWA TO A WINTER STORM WARNING FOR 6...POSSIBLY AS HIGH AS 9 INCHES OF SNOW...COMPOUNDED BY BLOWING SNOW OVERNIGHT INTO MONDAY MORNING. ALSO EXTENDED WARNING TO 9 AM MONDAY. THE SNOW AND BLOWING SNOW ADVISORY AND WINTER WEATHER ADVISORY REMAIN IN EFFECT TO THE SOUTH...ALSO TO 9 AM MONDAY...WITH LESSER AMOUNTS OF 4-6 AND 3-4 INCHES...RESPECTIVELY. GFS/NAM/RUC ALL INITIALIZED FAIRLY CLOSELY AT 12Z...ALBEIT ABOUT 2 DEGREES TOO WARM AT 850MB...BUT AT 18Z WERE A BIT COOLER COMPARED TO THE KDVN 18Z SPECIAL SOUNDING. MODEL QPF AND HEAVIER SNOW PLACEMENT WERE ALSO FAIRLY SIMILAR FOR THE REMAINDER OF THE EVENT. A RECENT CONCERN FOR THE ONGOING WARNING AREA WOULD BE DRY SLOT NOSING INTO FAR NW IOWA ATTM...HOWEVER ALL MODELS CONTINUE TO BULLSEYE NW IOWA WITH THE STRONGEST SYNOPTIC FORCING THROUGH THIS EVENING...AND THINKING IS ADDITIONAL AMOUNTS ON TOP OF 1 TO POSSIBLY 3 INCHES SO FAR WOULD PUT AREA INTO WARNING CRITERIA. BANDED SNOW CROSS SECTIONS AND FORECAST SOUNDINGS STILL INDICATE POTENTIAL FOR ENHANCED SNOWS INTO THE EVENING WITH SATURATED DENDRITIC LAYER LIFT...NEGATIVE EPV ABOVE SLOPING FRONTOGENESIS AREA...AND STEEP LAPSE RATE ALOFT FOR A PERIOD LATE THIS AFTERNOON AND EVENING. AREAS TO THE SOUTH MAY ALSO HAVE TO BE WATCHED...WITH A RECENT REPORT OF 4 INCHES IN NEMAHA IN FAR SOUTHEAST NEBRASKA. LOCAL SNOW TOOLS PRODUCED RATIOS OF 10-14:1 SE TO CENTRAL...UP TO 14-16:1 NORTHWEST SECTIONS...AND THIS SEEMED REASONABLE GIVEN CLIMO OF 12-13:1 AND MORE FAVORABLE DENDRITIC PROFILE NW. BLOWING SNOW STILL EXPECTED TO BE AN ISSUE OVERNIGHT INTO MONDAY MORNING WITH GUSTS UP TO 30 MPH AT TIMES. THEN TAPERED SNOW TO FLURRIES MONDAY AFTERNOON INTO THE EVENING EAST. DIDN/T FIDDLE WITH ONGOING TEMPERATURE FORECAST TOO MUCH...AS ADDITIONAL ADJUSTMENTS WILL LIKELY BE NECESSARY DEPENDING ON HOW THE SNOW PANS OUT. .EXTENDED /WED-SUN/... ADDED SMALL POPS FOR THURSDAY IN THE NORTHERN SECTIONS WITH MODELS ADVERTISING A WEAK COLD FRONT THROUGH THE REGION. DRY FORECAST OTHERWISE. ONLY LIMITED ANALYSIS OF EXTENDED PERIOD DUE TO NEAR TERM WINTER STORM. HPC GUIDANCE TEMPS LOOK SUITABLY COLD GIVEN EXPECTED SNOW COVER. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING ALONG AND NORTH OF A LINE FROM SAC CITY...TO WEBSTER CITY...TO HAMPTON THROUGH 9 AM MONDAY. SNOW AND BLOWING SNOW ADVISORY FOR THE REST OF THE FORECAST AREA EXCEPT THE SOUTHEAST THROUGH 9 AM MONDAY. WINTER WEATHER ADVISORY SOUTHEAST OF A CORYDON...ALBIA...OSKALOOSA LINE THROUGH 9 AM MONDAY. && $$ KINNEY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 338 PM CST SUN JAN 14 2007 .SHORT TERM /TONIGHT-TUES NIGHT/... ONGOING WINTER STORM THE MAIN FOCUS TODAY. UPDATED HEADLINES ARE OUT. IN SUMMARY...UPGRADED SNOW AND BLOWING SNOW ADVISORY IN NORTHERN IOWA TO A WINTER STORM WARNING FOR 6...POSSIBLY AS HIGH AS 9 INCHES OF SNOW...COMPOUNDED BY BLOWING SNOW OVERNIGHT INTO MONDAY MORNING. ALSO EXTENDED WARNING TO 9 AM MONDAY. THE SNOW AND BLOWING SNOW ADVISORY AND WINTER WEATHER ADVISORY REMAIN IN EFFECT TO THE SOUTH...ALSO TO 9 AM MONDAY...WITH LESSER AMOUNTS OF 4-6 AND 3-4 INCHES...RESPECTIVELY. GFS/NAM/RUC ALL INITIALIZED FAIRLY CLOSELY AT 12Z...ALBEIT ABOUT 2 DEGREES TOO WARM AT 850MB...BUT AT 18Z WERE A BIT COOLER COMPARED TO THE KDVN 18Z SPECIAL SOUNDING. MODEL QPF AND HEAVIER SNOW PLACEMENT WERE ALSO FAIRLY SIMILAR FOR THE REMAINDER OF THE EVENT. A RECENT CONCERN FOR THE ONGOING WARNING AREA WOULD BE DRY SLOT NOSING INTO FAR NW IOWA ATTM...HOWEVER ALL MODELS CONTINUE TO BULLSEYE NW IOWA WITH THE STRONGEST SYNOPTIC FORCING THROUGH THIS EVENING...AND THINKING IS ADDITIONAL AMOUNTS ON TOP OF 1 TO POSSIBLY 3 INCHES SO FAR WOULD PUT AREA INTO WARNING CRITERIA. BANDED SNOW CROSS SECTIONS AND FORECAST SOUNDINGS STILL INDICATE POTENTIAL FOR ENHANCED SNOWS INTO THE EVENING WITH SATURATED DENDRITIC LAYER LIFT...NEGATIVE EPV ABOVE SLOPING FRONTOGENESIS AREA...AND STEEP LAPSE RATE ALOFT FOR A PERIOD LATE THIS AFTERNOON AND EVENING. AREAS TO THE SOUTH MAY ALSO HAVE TO BE WATCHED...WITH A RECENT REPORT OF 4 INCHES IN NEMAHA IN FAR SOUTHEAST NEBRASKA. LOCAL SNOW TOOLS PRODUCED RATIOS OF 10-14:1 SE TO CENTRAL...UP TO 14-16:1 NORTHWEST SECTIONS...AND THIS SEEMED REASONABLE GIVEN CLIMO OF 12-13:1 AND MORE FAVORABLE DENDRITIC PROFILE NW. BLOWING SNOW STILL EXPECTED TO BE AN ISSUE OVERNIGHT INTO MONDAY MORNING WITH GUSTS UP TO 30 MPH AT TIMES. THEN TAPERED SNOW TO FLURRIES MONDAY AFTERNOON INTO THE EVENING EAST. DIDN/T FIDDLE WITH ONGOING TEMPERATURE FORECAST TOO MUCH...AS ADDITIONAL ADJUSTMENTS WILL LIKELY BE NECESSARY DEPENDING ON HOW THE SNOW PANS OUT. .EXTENDED /WED-SUN/... ADDED SMALL POPS FOR THURSDAY IN THE NORTHERN SECTIONS WITH MODELS ADVERTISING A WEAK COLD FRONT THROUGH THE REGION. DRY FORECAST OTHERWISE. ONLY LIMITED ANALYSIS OF EXTENDED PERIOD DUE TO NEAR TERM WINTER STORM. HPC GUIDANCE TEMPS LOOK SUITABLY COLD GIVEN EXPECTED SNOW COVER. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING ALONG AND NORTH OF A LINE FROM SAC CITY...TO WEBSTER CITY...TO HAMPTON THROUGH 9 AM MONDAY. SNOW AND BLOWING SNOW ADVISORY FOR THE REST OF THE FORECAST AREA EXCEPT THE SOUTHEAST THROUGH 9 AM MONDAY. WINTER WEATHER ADVISORY SOUTHEAST OF A CORYDON...ALBIA...OSKALOOSA LINE THROUGH 9 AM MONDAY. && $$ KINNEY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 154 PM CST MON JAN 15 2007 .DAYS 1-2... MAIN CHALLENGE IS THE FIRST PERIOD AND JUST HOW COLD IT WILL GET TONIGHT...ESPECIALLY OUT WEST OVER THE HIGH PLAINS "GLACIER". NORTHWEST WINDS WILL ABATE BY EARLY EVENING AND SHOULD SEE TEMPERATURES DROP RAPIDLY INTO THE 3 TO 6F DEGREE RANGE JUST BEFORE MIDNIGHT. THE AMOUNT OF CONTINUED DROPPING OF TEMPERATURE WILL BE CONTROLLED BY HOW MUCH WIND THERE WILL BE...THE NAM AND RUC BOTH SUGGEST JUST ENOUGH OF A NORTHWEST WIND AROUND 4 TO 6 KNOTS TO KEEP FROM WIDESPREAD BELOW ZERO READINGS. HOWEVER IF WINDS DO SLACKEN OFF TO DEAD CALM FOR A FEW HOURS...THEN WE SHOULD SEE QUITE A FEW READINGS IN THE -4 TO -8F RANGE...THIS IS STILL RATHER UNCERTAIN SO WILL GO WITH AROUND -2 TO -3 OVER THE SNOWPACK IN THE WEST TO AROUND +2 OR +3 OVER THE SOUTHEASTERN CWA. FOR TUESDAY...CENTER OF 900MB ANTICYCLONE WILL BE PRETTY MUCH CENTERED OVER SOUTHWEST KANSAS BY LATE AFTERNOON. WINDS WILL BE VERY LIGHT DURING THE DAY...AND AM NOT EXPECTING MUCH OF A WARM-UP OVER WHAT WE ARE SEEING TODAY FOR HIGHS...WITH PERHAPS A FEW UPPER 20S READINGS WHERE THERE IS MORE BARE GROUND OVER CENTRAL PORTIONS OF THE CWA. TUESDAY NIGHT...LOW LEVEL ANTICYCLONE FINALLY SHIFTS FAR ENOUGH SOUTHEAST TO PUT SOUTHWEST KS INA RETURN SOUTHERLY FLOW...IT CERTAINLY WILL NOT BE A WARM WIND THOUGH. LOWS TUES NIGHT WILL NOT BE AS COLD WITH STRONGER SOUTH WINDS EXPECTED. LEESIDE PRESSURE FALLS WILL OCCUR IN ADVANCE OF BOTH A NORTHERN STREAM MID LEVEL TROUGH AND A WEAK SOUTHERN STREAM SYSTEM. WEDNESDAY...SOUTH WINDS WILL INCREASE QUITE A BIT WITH LEE TROUGH BECOMING STRONGER TO THE NORTHWEST AS MID LEVEL SHORTWAVE TROUGH PASS THROUGH THE PLAINS. A NORTHWARD SURGE OF LOWER-MID TROPOSPHERIC MOISTURE IS ALSO EXPECTED...HOWEVER LIMITED LIFT AND BAROCLINICITY WILL NEGATE PRECIPITATION FORMATION...JUST AN INCREASE IN CLOUDS BY MIDDAY. -UMSCHEID .DAYS 3-7... MODELS DIFFER SLIGHTLY ON LOCATION OF UPPER CLOSED LOW LINGERING OVER THE PACIFIC JUST WEST OF THE SOUTHERN CA COAST. ALSO SEEING DISCREPANCIES BETWEEN MODELS REGARDING DEPTH OF TROUGHING ACROSS THE CENTRAL PLAINS (MAINLY ACROSS WESTERN KS). GFS/CANADIAN ARE A BIT DEEPER ALLOWING SLIGHTLY COLDER H85 TEMPERATURES TO SPILL ACROSS THE CWA. UKMET IS SLOWEST SOLUTION BRINGING THE H5 CLOSED LOW INTO THE CONUS. OTHER MODELS ALL MOVE LOW ONSHORE BY 00Z SUN. FOR NOW, A MODEL BLEND WITH LESS WEIGHT ON THE OUTLIER, THE UKMET, WILL BE USED. MAIN QUESTION CONTINUES TO BE PRECIPITATION CHANCES INTO THE WEEKEND. MUCH UNCERTAINTY REMAINS ON HOW/WHEN UPPER LOW WILL MOVE INTO SOUTHERN CA. ONCE ONSHORE, THE SYSTEM LOCATION WILL MAKE A BIG DIFFERENCE ON WHETHER OR NOT WESTERN KS WILL RECEIVE ANY PRECIPITATION. MODELS DO HANG ONTO A DECENT SUBTROPICAL JET ALLOWING PLENTY OF MOISTURE RETURN ACROSS WESTERN TX. STRONG HIGH PRESSURE FORECAST TO MOVE SOUTH THUS KEEPING BULK OF PRECIP SOUTH OF CWA. EVEN IF MOISTURE DOES MAKE IT INTO SOUTHWEST KS, IT DOES NOT APPEAR THAT IT WILL ARRIVE UNTIL LATE SATURDAY NIGHT OR SUNDAY (GIVE SOLUTION IS CORRECT). DECIDED TO BACK OFF ON POPS ACROSS CWA DURING THIS PERIOD. HAVE LEFT A SLIGHT CHANCE ACROSS THE SOUTHWESTERN COUNTIES STARTING SATURDAY NIGHT SINCE IT IS POSSIBLE THAT SOME MOISTURE WILL MAKE IT INTO THIS REGION. REMAINDER OF CWA WILL BE DRY. ONCE AGAIN, WILL HAVE TO KEEP A CLOSE EYE ON EVOLUTION OF THIS SYSTEM SINCE DETAILS ARE RATHER SKETCHY AT PRESENT. BESIDES WEATHER AND POPS, NO OTHER MAJOR GRID CHANGES WERE MADE. && .PRELIMINARY POINT TEMPS/POPS... DDC 1 27 9 33 / 0 0 0 0 GCK -3 26 7 31 / 0 0 0 0 EHA 1 27 13 32 / 0 0 0 0 LBL 2 29 13 33 / 0 0 0 0 HYS 0 24 9 33 / 0 0 0 0 P28 2 24 6 30 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN25/30 ks AREA FORECAST DISCUSSION...UPDATED WWA SECTION NATIONAL WEATHER SERVICE TOPEKA KS 1045 PM CST SAT JAN 13 2007 .DISCUSSION... WENT AHEAD AND REPLACED THE WATCH WITH ADVISORIES. WITH THE POSSIBILITY FOR A MIX OF SLEET AND SNOW...WENT WITH A WINTER WEATHER ADVISORY RUFFLY FROM EMPORIA TO HIAWATHA. SNOW IS EXPECTED TO BE THE PRIMARY PRECIP TYPE ACROSS NORTH CENTRAL KS...SO HAVE ISSUED A SNOW ADVISORY FOR THESE AREAS. THE WINTER STORM WARNING REMAINS UNCHANGED FROM PREVIOUS SHIFTS. && WOLTERS .PREV DISCUSSION /907 PM CST SAT JAN 13 2007/... WILL UPDATE THE FORECAST SHORTLY FOR CURRENT CONDITIONS. FOR THE MOST PART...PRECIP HAS ENDED ACROSS MOST OF THE FORECAST AREA. THERE ARE SOME SMALL BANDS OF VERY LIGHT PRECIP SEEN ON RADAR. IT IS HARD TO TELL IF THE PRECIP FALLING IS LIGHT FREEZING DRIZZLE OR POSSIBLY SNOW NEEDLES...ITS THAT LIGHT. THE LATEST RUC FORECAST WAS SHOWING SOME VERY LIGHT ISENTROPIC LIFT WITHIN THE CLOUD. THINK THIS MAY BE THE REASON FOR THE LIGHT PRECIP. NEVERTHELESS DO NOT ANTICIPATE ANY ACCUMULATING PRECIP FOR THE REST OF THE NIGHT SINCE LARGE SCALE FORCING HAS LEFT THE AREA FOR THE TIME BEING. MAIN QUESTION IS WHAT TO DO WITH THE WATCH. AM CONSIDERING REPLACING THE WATCH WITH AN ADVISORY OF SOME SORT. THE 00Z NAM IS COMING IN SHOWING A SIMILAR SOLUTION TO THE DAY TIME RUNS. AS THE BASE OF THE UPPER LEVEL TROUGH ROTATES THROUGH THE SOUTHER ROCKIES AND INTO THE WESTERN CENTRAL PLAINS...LARGE SCALE FORCING IS EXPECTED TO AFFECT THE AREA ONCE AGAIN. HOWEVER THE FORCING DOES NOT LOOK TERRIBLY IMPRESSIVE WITH THE UPPER WAVE SHEARING OUT AS IT MOVES INTO THE PLAINS. WILL WAIT TO REPLACE THE WATCH AND PEEK AT THE 00Z GFS TO SEE IF IT SHOWS SOMETHING DIFFERENT FROM THE EARLIER RUNS. IF THE NAM IS CORRECT...LOOKS LIKE MAINLY SNOW WILL FALL ACROSS AREAS NORTH AND WEST OF MHK WITH AROUND 2 INCHES POSSIBLE. ALONG THE TURNPIKE WILL BE A LITTLE MORE PROBLEMATIC GIVEN FORECAST SOUNDINGS STILL SHOWING A WARM NOSE AROUND 800MB THROUGH 21Z. WILL KEEP THE WINTER STORM WARNING AS IS FOR THE TIME BEING...GIVEN THE POSSIBILITY FOR DECENT SLEET ACCUMULATIONS ONCE AGAIN. AVIATION WISE...EXPECT CURRENT CONDITIONS TO REMAIN RELATIVELY STABLE THROUGH THE OVERNIGHT PERIOD. OBVIOUSLY THE LIGHT PRECIP SEEN ON RADAR WILL CAUSE A PROBLEM FOR AIRCRAFT. THIS SHOULD BE SPOTTY THOUGH AND CONFINED TO AREAS BELOW 4000FT. SFC VIS WILL DROP TO AROUND 4SM IN THESE LIGHT BANDS WITH CEILINGS AROUND 800FT. OTHERWISE ANTICIPATE A SLIGHT IMPROVEMENT TO THE CEILINGS AROUND 1000FT AS VERY WEAK ISENTROPIC LIFT BREAKS DOWN. && WOLTERS .PREV DISCUSSION /340 PM CST SAT JAN 13 2007/... CURRENTLY...SLEET SHOWERS EXITING THE CWA TO THE EAST WITH SOME LIGHT SNOW FILLING IN BEHIND. CONDITIONS HAVE IMPROVED ENOUGH TO LIFT ADVISORY ALL AREAS...AND WILL LET IT GO WITH THE AFTERNOON PACKAGE. ANTICIPATING A LULL IN THE WEATHER FOR TONIGHT AS TODAYS SYSTEM DEPARTS EAST AND UPPER TROF STILL LUMBERING INTO THE GREAT BASIN. BASE OF THE MAIN TROF PROGGED TO MAKE IT INTO NORTHERN NM BY MORNING...EJECTING SHORTWAVES INTO SOUTH CENTRAL KANSAS AT THAT TIME AS WELL. GFS STRONGER WITH THESE FEATURES...AND WHILE SEVERAL WAVES ARE SEEN OVER THE SW US IN THE WATER VAPOR...STILL DIFFICULT TO DISCERN WHICH WILL MAKE IT HERE AND WHEN. CONSENSUS SEEMS TO BE THAT BEST WINDOW FOR ACCUMULATING SNOWS IS NOW MAINLY IN THE 15Z-0Z TIMEFRAME. GUIDANCE NUMBERS FOR SNOW HAVE COME DOWN...AND NOT MUCH INSTABILITY IN THE COLUMN. BUT WITH SOME FRONTOGENESIS...POT VORT AND Q VECTOR CONVERGENCE STILL OCCURING OVER OUR AREA AT THIS TIME...WILL KEEP SOME ADVISORY ACCUMULATIONS IN THE FORECAST FOR MUCH OF THE CWA. FAR SE COUNTIES WHERE WARNING IS IN EFFECT HAVE ALREADY SEEN OVER AN INCH OF SLEET IN PLACES...AND WILL BE EXACERBATED BY SOME SNOW ACCUMULATION ON TOP OF THIS TOMORROW. WITH PWS AROUND HALF AN INCH AND SNOW RATIOS LIKELY OVER 10/1 IN THE COLD AIR...AM NOT READY TO DROP THE WATCH JUST YET...AND WILL TREND GRIDS TOWARDS ADVISORY NUMBERS. MAIN UPPER LEVEL WAVE FINALLY EJECTS OUT THROUGH THE PLAINS AND EXITS TO THE NORTHEAST OF THE CWA BY 12Z MONDAY...BUT NOT BEFORE PRODUCING SOME LIGHT SNOW ACROSS THE CWA...MAINLY DURING THE EVENING ALONG AND NORTH OF I-70 AS DRIER AIR AND SUBSIDENCE INCREASE FROM THE SOUTHWEST. ADDITIONAL AMOUNTS GENERALLY SHOULD BE FROM LESS THAN HALF AN INCH SOUTH TO AN INCH TO AN INCH AND A HALF NORTHEAST CORNER OF THE CWA. ALTHOUGH LOWS SUNDAY NIGHT WILL BE COLDER...CLOUDS AND INCREASING WINDS WILL KEEP TEMPERATURES FROM FALLING AS MUCH AS THEY OTHERWISE WOULD...SO WILL KEEP GENERALLY IN THE 5 TO 12 DEGREE RANGE. THE STRATUS ON MONDAY WILL THEN LINGER IN THE MORNING BUT START TO BREAK UP BY AFTERNOON. STILL...WITH EXPECTED SNOW/ICE COVER...THIS WILL LIMIT HIGHS TO THE TEENS. TUESDAY NIGHT SHOULD BE THE COLDEST NIGHT WITH DIMINISHING WINDS...DECREASING CLOUDS AND SNOW/ICE COVER. WILL GO WITH MOST TEMPS NEAR ZERO FOR NOW...BUT DEPENDING ON SNOW/ICE DEPTHS...COULD SEE TEMPS A FEW DEGREES COLDER. ALTHOUGH SUNSHINE SHOULD BE THE RULE ON TUESDAY...MIXING WILL BE WEAK FOLLOWING VERY COLD MORNING LOWS...SO THIS WILL LIMIT HIGHS TO UPPER TEENS TO LOWER 20S. RETURN FLOW ON THE BACK SIDE OF THE HIGH SHOULD THEN KEEP LOWS ABOVE ZERO INTO WEDNESDAY MORNING WITH MOST HIGHS IN THE MIDDLE TO UPPER 20S. WILL KEEP THE REST OF THE FCST DRY ON THROUGH EARLY NEXT WEEKEND AS THE GFS/ECMWF SEEMS TOO PROGRESSIVE AND TOO FAR EAST WITH CUTOFF LOW COMING OUT OF THE SOUTHWEST U.S. WEDNESDAY. ALSO LOW CONFIDENCE WITH THE ARRIVAL TIME OF THE NEXT SYSTEM BY SATURDAY. EITHER WAY...WITH THE SNOW/ICE COVER WILL SEE A "GRADUAL" MODERATION IN TEMPS THROUGH THE REST OF THE WEEK INTO THE 30S THURSDAY AND FRIDAY AND SOME LOWER 40S SOUTHERN CWA BY NEXT WEEKEND. && .TOP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING THROUGH 06Z MONDAY FOR COFFEY...FRANKLIN AND ANDERSON COUNTIES. WINTER WEATHER ADVISORY FROM 16Z SUNDAY UNTIL 06Z MONDAY FOR LYON... MORRIS...WABAUNSEE...OSAGE...SHAWNEE...DOUGLAS...JEFFERSON...JACKSON AND BROWN COUNTIES. SNOW ADVISORY FROM 16Z SUNDAY UNTIL 06Z MONDAY FOR ALL OTHER COUNTIES. && $$ ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LOUISVILLE KY 910 PM EST MON JAN 15 2007 .UPDATE... WITHIN COLD ADVECTION/POST FRONTAL LOW CLOUDS...AREAS OF LIGHT PRECIP ARE MOVING THROUGH THE LMK CWA AS OF 2Z. BASED ON RECENT ACARS SOUNDINGS AT SDF...AND MOST RECENT RUC MODEL...PRECIP TYPE SHOULD BE LIQUID. ADDITIONAL LIGHT PRECIP OBSERVED UPSTREAM OVER IL/IN...HEADING IN THIS GENERAL DIRECTION. OVERNIGHT...PTYPE WILL BE TRICKY. AS IS THE SITUATION RIGHT NOW...FCST SOUNDINGS FROM NAM/GFS/RUC SHOW ATMOSPHERE ABOVE -5C OR SO REMAINING FAIRLY DRY OVERNIGHT...LEADING TO MORE OF A DRIZZLE ENVIRONMENT. THIS IS EVEN AS THE NEAR SURFACE LEVELS COOL TO NEAR OR BELOW FREEZING. WILL UPDATE FCST TO ADD MENTION OF PATCHY -FZDZ LATE TONIGHT AND EARLY TUESDAY MORNING OVER THE N 1/2 OF THE LMK CWA...ALSO MENTIONING SLIGHT CHANCES FOR -SHRA/-SHSN FOR ANY ISOLATED ELEMENTS WHICH CAN SATURATE UP INTO THE -10C TO -20C LEVELS OVERNIGHT. ROADWAY TEMPS RIGHT NOW ARE RELATIVELY WARM...UPPER 30S TO LOWER 40S...BUT EXPECT THOSE TO COOL OVERNIGHT ESPECIALLY IN SRN IND AND ADJACENT PARTS OF KY. EVEN JUST A LITTLE -FZDZ CAN HAVE A BIG IMPACT. INTO TUESDAY...MODELS ARE INDICATING THAT A PLUME OF ENHANCED MOISTURE ORIGINATING FROM LAKE MICH MAY CONTRIBUTE TO SOME SCT SHSN INTO PARTS OF THE BLUEGRASS AND NE KY. ONGOING FCST HAS THIS WELL IN HAND...BUT HAVE UPPED POPS INTO 40% RANGE FOR OUR FAR NE MOST COUNTIES BASED ON MOST RECENT DATA. SOME LOCALIZED MINOR ACCUMS POSSIBLE THERE SHOULD THESE SHOWERS MATERIALIZE. NO SIGNIFICANT CHANGES TO TEMPS/WINDS/DEWPOINTS/CLOUDS TONIGHT AND TUESDAY. UPDATED FCST EXPECTED OUT BY 945 PM EST. CS && .PREV DISCUSSION... /ISSUED 328 PM EST MON JAN 15 2007/ SHORT TERM (TONIGHT AND TUESDAY).. FRONTAL BOUNDARY THAT HAS BEEN RESPONSIBLE FOR THE RAINY WEATHER OF LATE CONTINUES TO MOVE EAST THROUGH THE COMMONWEALTH. LARGE POST FRONTAL BAND OF PRECIPITATION CONTINUES TO AFFECT THE SOUTHEASTERN HALF OF THE FA. PRECIPITATION CONTINUES TO MOVE STEADILY EASTWARD AND SHOULD EXIT THE LMK FORECAST AREA BETWEEN 400 AND 500 PM EST. TEMPERATURES CONTINUE TO FALL IN THE WAKE OF THE FRONT. SIGNIFICANTLY COOLER AIR STILL RESIDES WELL WEST OF THE FA. TEMPERATURES ARE FALLING INTO THE UPPER 30S NOW ACROSS THE NORTHWEST CWA AND THIS TREND SHOULD CONTINUE. THE RUC SFC TEMP FCST HAS BEEN DOING A BANG UP JOB WITH THIS AND WILL FOLLOW ITS FORECAST CLOSELY FOR TEMPERATURES THIS AFTERNOON AND EVENING. WITH THE THREAT OF EXCESSIVE RAIN COMING TO AN END...THE FLOOD WATCH WILL BE ALLOWED TO EXPIRE AT 400 PM EST/300 PM CST. FOR TONIGHT...SHORT TERM MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE FIRST 24 HOURS OF THE FCST PD. POST FRONTAL PRECIP IS FCST TO BE WELL EAST OF THE FA BY 00Z TONIGHT. LATEST RUC AND WRF SOUNDINGS SUPPORT STEEPENING LOW-LEVEL LAPSE RATES THROUGH THE EVENING THAT WOULD PROMOTE AREAS OF DRIZZLE INITIALLY THROUGH ABOUT 03Z. AFTER THAT...SUFFICIENT TOP-DOWN COOLING WOULD RESULT IN A TRANSITION OVER TO SNOW FLURRIES FROM WEST TO EAST. UPSTREAM RADARS SHOWING SOME LIGHT SNOWS ACROSS NORTHERN MISSOURI AND NW ILLINOIS DROPPING EAST-SOUTHEAST. MODELS GENERALLY WEAKEN THIS AREA AND SHIFT IT NORTH OF THE OHIO RIVER. HOWEVER...WILL NEED TO WATCH THIS CLOSELY AS THE EVENING PROGRESSES. SFC TEMPERATURES WILL CONTINUE TO SLOWLY FALL THROUGH THE EVENING...WITH TEMPERATURES DROPPING TO NEAR FREEZING AROUND BETWEEN 06-08Z. OVERNIGHT MINIMUMS LOOKS TO COOL INTO THE MID AND UPPER 20S. TUESDAY...AS FRONTAL BOUNDARY CONTINUES EAST...HIGH PRESSURE IS FORECAST TO BUILD IN ACROSS THE MIDWEST. RESULTANT LOW-LEVEL FLOW WITH BE FROM THE NORTH/NORTH-NORTHWEST. WITH THE LAKES FAIRLY WARM DUE TO RECENT MILD WEATHER...LAKE EFFECT SNOW MACHINE IS FORECAST TO CRANK UP. BOTH WRF AND GFS SOLUTIONS SHOW BEST LAPSE RATES FOR SNOW SHOWERS ACROSS THE NE THIRD OF OUR FA (BLUEGRASS REGION). THUS WILL CONTINUE CHANCE OF SNOW SHOWERS ACROSS THAT AREA. STRONG COLD ADVECTION IS FCST TO CONTINUE AND AFTERNOON TEMPS WILL NOT RISE MUCH DURING THE AFTERNOON. HIGHS IN THE UPPER 20S TO THE VERY LOW 30S LOOK LIKELY. GENERALLY TRENDED TEMPS CLOSER TO RAW 2M SFC TEMPS FROM OUR LOCAL HI-REZ WRF AND GFS SOLUTIONS. -MJ LONG TERM (TUESDAY NIGHT THROUGH MONDAY)... TUESDAY NIGHT AND WEDNESDAY... WE WILL FINALLY SEE A GENERAL CLEARING TAKE PLACE ON LATE ON TUESDAY AND TUESDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION AND THEN SHIFTS OFF TO THE EAST ON WEDNESDAY. A RETURN TO MUCH COLDER BUT MORE NORMAL TEMPS. WEDNESDAY THROUGH SATURDAY NIGHT... WE WILL PRIMARILY BE UNDER A NORTHWESTERLY FLOW REGIME AT 500 MB AS THE WESTERN RIDGE...INITIALLY FLATTENED BY A SHORT WAVE ON TUESDAY THEN REBUILDS INTO SOUTHWESTERN CANADA...THE ABOVE MENTIONED SHORT WAVE WILL DROP ESE THROUGH THE CENTRAL U.S. AND BRING ANOTHER SURGE OF SEASONABLY COLD ARCTIC AIR INTO THE REGION AS A SURFACE RIDGE BUILDS SOUTHEAST INTO THE WESTERN PLAINS. A SERIES OF WEAKER SYSTEMS DRIFTING BY TO OUR NORTH AND EAST SHOULD HELP TO REINFORCE AND KEEP THE COLD AND DRY AIR IN PLACE THROUGH THE REST OF THIS PERIOD. THIS COULD LEAD TO SOME MIXED WINTERY PRECIPITATION LATER. SUNDAY AND MONDAY... THE GENERAL CONSENSUS IS THAT A CLOSED LOW WILL SETUP OFF THE SOUTHERN CALIFORNIA COAST LATE THIS WEEK. OVER THE WEEKEND THIS SYSTEM OPEN AND TREK ENE INTO THE CENTRAL U.S. BY LATE ON SUNDAY INTO MONDAY. INITIAL INDICATIONS ARE THAT THE ATMOSPHERE WILL BE COLD ENOUGH FOR A POSSIBLE SNOW TO RAIN SCENARIO ON SUNDAY NIGHT THAT DOES CHANGE OVER TO ALL RAIN ON MONDAY AS A SURFACE LOW MOVES INTO THE CENTRAL U.S. FROM THE SOUTHERN PLAINS. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 328 PM EST MON JAN 15 2007 .SHORT TERM (TONIGHT AND TUESDAY).. FRONTAL BOUNDARY THAT HAS BEEN RESPONSIBLE FOR THE RAINY WEATHER OF LATE CONTINUES TO MOVE EAST THROUGH THE COMMONWEALTH. LARGE POST FRONTAL BAND OF PRECIPITATION CONTINUES TO AFFECT THE SOUTHEASTERN HALF OF THE FA. PRECIPITATION CONTINUES TO MOVE STEADILY EASTWARD AND SHOULD EXIT THE LMK FORECAST AREA BETWEEN 400 AND 500 PM EST. TEMPERATURES CONTINUE TO FALL IN THE WAKE OF THE FRONT. SIGNIFICANTLY COOLER AIR STILL RESIDES WELL WEST OF THE FA. TEMPERATURES ARE FALLING INTO THE UPPER 30S NOW ACROSS THE NORTHWEST CWA AND THIS TREND SHOULD CONTINUE. THE RUC SFC TEMP FCST HAS BEEN DOING A BANG UP JOB WITH THIS AND WILL FOLLOW ITS FORECAST CLOSELY FOR TEMPERATURES THIS AFTERNOON AND EVENING. WITH THE THREAT OF EXCESSIVE RAIN COMING TO AN END...THE FLOOD WATCH WILL BE ALLOWED TO EXPIRE AT 400 PM EST/300 PM CST. FOR TONIGHT...SHORT TERM MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE FIRST 24 HOURS OF THE FCST PD. POST FRONTAL PRECIP IS FCST TO BE WELL EAST OF THE FA BY 00Z TONIGHT. LATEST RUC AND WRF SOUNDINGS SUPPORT STEEPENING LOW-LEVEL LAPSE RATES THROUGH THE EVENING THAT WOULD PROMOTE AREAS OF DRIZZLE INITIALLY THROUGH ABOUT 03Z. AFTER THAT...SUFFICIENT TOP-DOWN COOLING WOULD RESULT IN A TRANSITION OVER TO SNOW FLURRIES FROM WEST TO EAST. UPSTREAM RADARS SHOWING SOME LIGHT SNOWS ACROSS NORTHERN MISSOURI AND NW ILLINOIS DROPPING EAST-SOUTHEAST. MODELS GENERALLY WEAKEN THIS AREA AND SHIFT IT NORTH OF THE OHIO RIVER. HOWEVER...WILL NEED TO WATCH THIS CLOSELY AS THE EVENING PROGRESSES. SFC TEMPERATURES WILL CONTINUE TO SLOWLY FALL THROUGH THE EVENING...WITH TEMPERATURES DROPPING TO NEAR FREEZING AROUND BETWEEN 06-08Z. OVERNIGHT MINIMUMS LOOKS TO COOL INTO THE MID AND UPPER 20S. TUESDAY...AS FRONTAL BOUNDARY CONTINUES EAST...HIGH PRESSURE IS FORECAST TO BUILD IN ACROSS THE MIDWEST. RESULTANT LOW-LEVEL FLOW WITH BE FROM THE NORTH/NORTH-NORTHWEST. WITH THE LAKES FAIRLY WARM DUE TO RECENT MILD WEATHER...LAKE EFFECT SNOW MACHINE IS FORECAST TO CRANK UP. BOTH WRF AND GFS SOLUTIONS SHOW BEST LAPSE RATES FOR SNOW SHOWERS ACROSS THE NE THIRD OF OUR FA (BLUEGRASS REGION). THUS WILL CONTINUE CHANCE OF SNOW SHOWERS ACROSS THAT AREA. STRONG COLD ADVECTION IS FCST TO CONTINUE AND AFTERNOON TEMPS WILL NOT RISE MUCH DURING THE AFTERNOON. HIGHS IN THE UPPER 20S TO THE VERY LOW 30S LOOK LIKELY. GENERALLY TRENDED TEMPS CLOSER TO RAW 2M SFC TEMPS FROM OUR LOCAL HI-REZ WRF AND GFS SOLUTIONS. -MJ .LONG TERM (TUESDAY NIGHT THROUGH MONDAY)... TUESDAY NIGHT AND WEDNESDAY... WE WILL FINALLY SEE A GENERAL CLEARING TAKE PLACE ON LATE ON TUESDAY AND TUESDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION AND THEN SHIFTS OFF TO THE EAST ON WEDNESDAY. A RETURN TO MUCH COLDER BUT MORE NORMAL TEMPS. WEDNESDAY THROUGH SATURDAY NIGHT... WE WILL PRIMARILY BE UNDER A NORTHWESTERLY FLOW REGIME AT 500 MB AS THE WESTERN RIDGE...INITIALLY FLATTENED BY A SHORT WAVE ON TUESDAY THEN REBUILDS INTO SOUTHWESTERN CANADA...THE ABOVE MENTIONED SHORT WAVE WILL DROP ESE THROUGH THE CENTRAL U.S. AND BRING ANOTHER SURGE OF SEASONABLY COLD ARCTIC AIR INTO THE REGION AS A SURFACE RIDGE BUILDS SOUTHEAST INTO THE WESTERN PLAINS. A SERIES OF WEAKER SYSTEMS DRIFTING BY TO OUR NORTH AND EAST SHOULD HELP TO REINFORCE AND KEEP THE COLD AND DRY AIR IN PLACE THROUGH THE REST OF THIS PERIOD. THIS COULD LEAD TO SOME MIXED WINTERY PRECIPITATION LATER. .SUNDAY AND MONDAY... THE GENERAL CONSENSUS IS THAT A CLOSED LOW WILL SETUP OFF THE SOUTHERN CALIFORNIA COAST LATE THIS WEEK. OVER THE WEEKEND THIS SYSTEM OPEN AND TREK ENE INTO THE CENTRAL U.S. BY LATE ON SUNDAY INTO MONDAY. INITIAL INDICATIONS ARE THAT THE ATMOSPHERE WILL BE COLD ENOUGH FOR A POSSIBLE SNOW TO RAIN SCENARIO ON SUNDAY NIGHT THAT DOES CHANGE OVER TO ALL RAIN ON MONDAY AS A SURFACE LOW MOVES INTO THE CENTRAL U.S. FROM THE SOUTHERN PLAINS. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ WFO LMK ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1111 AM EST SUN JAN 14 2007 .SHORT TERM.../TODAY/...UPDATED MAIN CHANGES TO THE FORECAST FOR TODAY WAS TO LOWER POPS...AND RAISE TEMPERATURES. TEMPERATURES WERE RUNNING IN THE MID 60S ALREADY IN THE SOUTHERN PORTION OF THE CWA...TAPERING TO THE UPPER 50S IN THE NORTH. MORNING RADIOSONDE SOUNDINGS WOULD YIELD HIGH TEMPS AROUND 70 IN THE SOUTH...WITH LOWER TO MID 60S IN THE NORTH. THESE WILL LIKELY NEAR RECORD VALUES IN THE NORTH...AND EXCEED THEM IN THE SOUTH. THE RECORD HIGH TODAY AT JKL IS 68...AND 64 AT LOZ. MUCH OF THE PRECIP HAS MOVED NORTH OF THE CWA AS THE QUASI STATIONARY FRONT OSCILLATES BACK NORTH AHEAD OF AN APPROACHING WAVE. WENT WITH LIKELY POPS ACROSS THE EXTREME NORTH FOR THE AFTERNOON. WENT WITH LOW CHANCE POPS FOR MOST OF THE REMAINDER OF THE AREA. IN THE SOUTHEAST...WENT WITH A SLIGHT CHANCE. ALL MODELS SHOW A LULL IN THE PRECIP TODAY. WILL KEEP FLOOD WATCH GOING TODAY. EVEN WITH A LULL IN THE PRECIP...STREAMS AND CREEKS ARE RUNNING HIGH IN THE WATCH AREA. ANY ADDITIONAL PRECIP DURING THE AFTERNOON COULD SEND THESE TO NEAR BANK FULL OR ABOVE. THE BEST CHANCE FOR FLOODING WILL BE TONIGHT INTO MONDAY. AFTERNOON QPF SHOULD RANGE FROM NEAR ZERO IN THE SOUTH...TO NEAR 0.20 IN THE NORTH. SURFACE FRONT IS CURRENTLY RUNNING FROM JUST NORTH OF CVG...TO PAH. MOST OF THE PRECIP TODAY WILL BE FOCUSED NEAR THE FRONT. NO OTHER CHANGES WERE MADE TO THE FORECAST ATTM. THE EARLIER MORNING DISCUSSION IS BELOW. /TONIGHT THROUGH TUESDAY/ FRONT SHOULD EVENTUALLY MAKE ITS EASTWARD PUSH TONIGHT...AS A STRONG SHORT WAVE EJECTS OUT OF THE SOUTHERN PLAINS. WITH STRONG HIGH PRESSURE STILL SITTING OF THE SOUTHEASTERN UNITED STATES...FRONT WILL BE SLOW TO EXIT REGION. ANTICIPATING THAT FRONT WONT MOVE EAST OF JKL CWA UNTIL SOMETIME MONDAY NIGHT. LEFT IN FLOOD WATCH FOR NORTHWESTERN COUNTIES DUE TO PERSISTANT RAINS THERE. SOUTHERN HALF OF CWA HADNT SEEN NEARLY AS MUCH RAIN AS THE NORTHWEST...SO FLOODING IS NOT MUCH OF A CONCERN. WINDS AND DEWPOINTS WERE ALREADY IN GOOD SHAPE WITH ONLY A FEW MINOR TWEAKS MADE BASED UPON LATEST MODEL RUNS AND MOS GUIDANCE. MADE A FEW CHANGES TO SKY COVER FOR TONIGHT...MAINLY TO REFLECT SLOWER EASTWARD PROGRESS OF FRONT. POP FORECAST ALSO MODIFIED QUITE A BIT...WITH LOWER POPS INTRODUCED TO SOUTHERN HALF OF CWA AND A MUCH SLOWER ONSET OF MAIN PRECIPITATION EVENT. LOOKING FOR MAIN PUSH OF RAIN TO MOVE THROUGH THE CWA BEGINNING LATER TONIGHT THROUGH MONDAY NIGHT. SOME AREAS IN THE NORTHERN PORTION OF CWA COULD RECEIVE A COUPLE OF INCHES OF RAIN OUT THIS NEXT ROUND OF PRECIP. EVERYWHERE ELSE SHOULD RECEIVE LESS THAN AN INCH. COULD ALSO SEE SNOW SHOWERS LATE MONDAY NIGHT INTO TUESDAY...AS THE COLDEST AIR OF THE WINTER SEASON BEGINS TO FILTER INTO THE AREA BEHIND A DEPARTING COLD FRONT. FOR TEMPERATURES...WENT WITH A BLEND OF MAV/MET MOS ACROSS THE BOARD. WENT BELOW MOS FOR DAYTIME HIGHS...DUE TO EXTENSIVE CLOUD COVER...AND A BIT WARMER THAN MOS FOR OVERNIGHT LOWS SUNDAY NIGHT AND MONDAY NIGHT. WENT VERY CLOSE TO MEXMOS NUMBERS FOR WEDNESDAYS HIGHS. DEPENDING ON AMOUNT OF CLOUD COVER IN PLACE...A FEW AREAS COULD BE A BIT COOLER THAN MOS. .LONG TERM.../WEDNESDAY THROUGH SATURDAY/ MODELS SOLUTIONS FOR THE END OF THE WEEK HAVE CHANGED FROM THE PREVIOUS RUNS. GFS BRINGS MOISTURE...AND A SURFACE WAVE...UP FROM THE GULF OF MEXICO ON FRIDAY INTO SATURDAY. ECMWF HAS ALSO TRENDED FURTHER NORTH WITH THIS SYSTEM. DGEX AND NOGAPS KEEPS THIS FURTHER SOUTH. ALL MODELS SHOW AN APPROACHING COLD FRONT FOR LATER FRIDAY. INTRODUCED CHANCE POPS FOR FRIDAY INTO SATURDAY WITH ALL OF THIS IN MIND. ATTM...THINK THE COLD FRONT WILL LIKELY HAVE ENOUGH MOISTURE TO AT LEAST WARRANT CHANCE POPS FOR NOW. PRECIP TYPE IS IN QUESTION...WITH MARGINAL TEMPERATURES AT ALL LEVELS. FOR NOW...WENT WITH A MENTION OF RAIN AND SNOW. COLDER AIR WILL FILTER INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS THE COLD FRONT MOVES THROUGH. THERE IS STILL UNCERTAINTY IN THE LATER PORTION OF THE EXTENDED...SO THE FORECAST WILL LIKELY NEED TO BE FINE TUNED AS TIME GOES ON. && .AVIATION.../12Z TO 12Z/ FRONTAL BOUNDARY STALLED JUST NORTHWEST OF THE AREA CONTINUES TO SEND WAVES OF SHOWERS NORTH OF INTERSTATE 64. NO REAL REASON FOR THE FRONT TO PUSH SOUTH...AND IN FACT IT WILL LIKELY WAFFLE BACK NORTH SOME TODAY AS LOW PRESSURE FORMS OVER THE LOWER MISSISSIPPI VALLEY AND THEN HEADS NORTH. THIS SHOULD RESULT IN AREA TAF SITES REMAINING VFR THROUGH THE DAY. ONE WRINKLE IN THIS THEORY IS A CONVECTIVELY INDUCED VORTICITY MAXIMUM WHICH SHOWS UP ON WATER VAPOR SATELLITE IMAGERY OVER MISSISSIPPI. RUC...AND TO SOME EXTENT THE NAM...PICK UP ON THIS FEATURE AND MOVE IT NORTHEAST ACROSS THE AREA THIS AFTERNOON. THIS MAY PROVIDE ENOUGH LIFT FOR SOME SHOWERS...BUT WILL MAINTAIN VFR CONDITIONS FOR NOW. CONDITIONS SHOULD FINALLY DETERIORATE LATER TONIGHT AS THE SURFACE WAVE MOVES NORTHEAST ACROSS THE WESTERN HALF OF THE STATE. HAVE DELAYED ONSET OF MVFR CIGS/VSBYS A FEW HOURS FROM EARLIER THINKING AS LATEST GUIDANCE IS A TOUCH SLOWER AND FARTHER WEST WITH THE SURFACE LOW. WINDS WILL ALSO BECOME GUSTY AFTER MIDNIGHT WITH SOME BORDERLINE LLWS AS MODELS DEVELOP A STRONG LOW LEVEL JET IN EXCESS OF 40 KT AROUND 2K FT AGL AND ABOVE. && .JKL WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH MONDAY AFTERNOON FOR KYZ044-050>052-058>060- 104-106-108. && $$ SHORT TERM...WJM/AR LONG TERM...WJM AVIATION...ABE ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1032 AM EST SUN JAN 14 2007 .MORNING UPDATE... QUASI STATIONARY FRONTAL BOUNDARY IS STILL DRAPED ACROSS THE AREA THIS MORNING. LOTS OF CLOUDS AND SEVERAL AREAS OF LIGHT PRECIPITATION WERE NOTED ACROSS THE REGION THIS MORNING. GENERAL DOWNWARD TREND IN PRECIPITATION HAS BEEN NOTED AND THIS WILL LIKELY CONTINUE THROUGH THE EARLY AFTERNOON AS EARLY MORNING SFC WAVE CONTINUES TO MOVE NE AND AWAY FROM THE REGION. FOR THE REMAINDER OF THE MORNING AND INTO THE AFTERNOON...LOOKS LIKE WE`LL SEE A SHORT LULL IN THE ACTION AS WE WILL BE IN BETWEEN SFC WAVES. AREAS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE TO MOVE ACROSS THE REGION WITH BEST PRECIP CHANCES ALONG AND NORTH OF A LINE FROM ALLEN COUNTY TO LINCOLN COUNTY. THOSE FAR SE COUNTIES MAY STAY FAIRLY DRY THROUGH THE AFTERNOON. AS FOR TEMPERATURES...WE WILL CONTINUE TO SEE A DECENT GRADIENT ACROSS THE REGION. AFTERNOON HIGHS IN THE MID TO UPPER 50S WILL BE SEEN IN SOUTHERN INDIANA WITH 60S ALONG AND SOUTH OF THE OHIO RIVER ACROSS NORTH CENTRAL AND THE BLUEGRASS REGION OF KY. 62-66 DEGREE READINGS WILL BE POSSIBLE ACROSS THE SE THIRD OF THE REGION. CURRENT FCST HAS THIS WELL IN HAND AND ONLY SOME MINOR ADJUSTMENTS TO TEMPS WILL BE NEEDED. GENERAL CONSENSUS OF 06Z AND EARLY 12Z MODEL DATA SUGGEST NEXT WAVE TO MOVE INTO THE REGION LATE THIS AFTERNOON AND EVENING. LIGHT TO MODERATE RAIN WILL OVERSPREAD THE REGION FROM WEST TO EAST TONIGHT. AXIS OF HIGHEST PRECIPITATION AGAIN LOOKS TO BE ALONG THE OHIO RIVER WITH THE HIGHEST QPF IN OUR WEST CENTRAL SECTIONS (SOUTH OF THE OHIO AND WEST OF I-65). THEREFORE...WILL ALLOW POPS TO RAPIDLY INCREASE FROM WEST TO EAST DURING THE LATE AFTERNOON HOURS. HYDRO ISSUES...PRECIP AMOUNTS FROM THE PAST 24 HOURS HAVE BEEN BETWEEN 0.75 AND A LITTLE OVER ONE INCH. THIS HAS RESULTED IN RISES ON AREA RIVERS...BUT AS A WHOLE...THINGS HAVE BEEN OKAY SO FAR. GROUND SATURATION HAS NOW BEEN REACHED OVER MUCH OF THE REGION AND FLASH FLOOD GUIDANCE CONTINUES TO DROP. THUS...WITH ADDITIONAL RAINFALL LATE THIS AFTERNOON AND TONIGHT...WE COULD START SEEING SOME HYDRO ISSUES IN OUR WESTERN COUNTIES. THERE IS SOME CONCERN THAT THE FLOODING AND HYDRO ISSUES MAY NOT BE REALIZED IN THE SE SECTIONS OF THE FA. HOWEVER...THE 06Z GFS SOLUTIONS DO BRING DECENT QPF AMOUNTS INTO THE AREA LATE TONIGHT AND MONDAY. THEREFORE...WE MAY NEED TO EXTEND THE FLOOD WATCH IN TIME THROUGH MONDAY MORNING. DECISIONS ON THE FLOOD WATCH WILL BE MADE DURING THE AFTERNOON PACKAGE AS FULL 12Z MODEL DATA WILL BE AVAILABLE. AS FOR RIVER IMPACTS...WITH THE RAIN THATS ALREADY FALLEN AND EXPECTED QPF FOR TONIGHT...OUR OHIO RIVER POINTS STILL LOOK TO GO INTO MINOR FLOOD IN THE NEXT FEW DAYS. WE`RE ALSO WATCHING THE ROLLING FOR RIVER AND GREEN RIVERS IN KY AS EXPECTED QPF WILL PUSH THEM INTO MINOR FLOODING AS WELL. UPDATED FCST SUITE AND PRODUCTS WILL BE AVAILABLE BY 1130 AM EST. -MJ PREVIOUS FCST DISCUSSION... .SHORT TERM (TODAY AND TONIGHT)... CURRENTLY...A QUASI-STATIONARY FRONT IS ALIGNED ROUGHLY FROM SOUTH OF CINCINNATI...TO LOUISVILLE...TO MEMPHIS. SFC LOW PRESSURE WAVES RIDING ALONG THIS FRONT AND AMPLE MOISTURE HAVE BEEN RESPONSIBLE FOR THE RAINFALL OVER THE PAST 1-2 DAYS. RAINFALL TOTALS ACROSS THE CWA OVER THE PAST 24 HOURS HAVE RANGED FROM AROUND A TENTH OF AN INCH ACROSS THE SERN CWA TO ROUGHLY THREE- QUARTERS OF AN INCH ACROSS THE WNW. ANOTHER SFC WAVE OVER WRN TN IS HELPING PUMP MOISTURE NORTHWARD ALONG THE FRONT INTO OUR WRN CWA ATTM. THIS WILL BE THE FIRST OF TWO MAIN WAVES OF MOD-TO-HEAVY RAINFALL FOR THE CWA. BASED OFF THE 00Z NAM (WHICH HAS THE BEST HANDLE ON CURRENT RADAR IMAGERY)...THE TN SFC WAVE WILL RIDE ALONG THE FRONT WHICH WILL BE NEARLY PARALLEL TO THE OHIO RIVER. THUS THE HEAVIEST RAINFALL IS EXPECTED ALONG AND AROUND THE OHIO RIVER THROUGH THE MORNING HOURS AND PERHAPS INTO THE EARLY AFTERNOON HOURS. BOTH THE NAM AND RUC (AND WRF) THINK THAT OUR SERN CWA COULD GET BY TODAY WITH ONLY A FEW LIGHT RAIN SHOWERS. HAVE BACKED OFF ON POPS DOWN THERE TO ACCOUNT FOR THIS TREND. EVEN THOUGHT OF CANCELING THE WATCH ACROSS OUR FAR SERN CWA...BUT WE MAY SEE ENOUGH PRECIP WITH THE SECOND WAVE TO JUSTIFY IT. SOMETHING THE NEXT SHIFT WILL CERTAINLY HAVE TO CONSIDER THOUGH. WELL...THE FIRST WAVE OF POTENTIALLY HEAVY RAIN IS CURRENTLY CAUSING MINOR FLOODING PROBLEMS IN PAH`S CWA...BUT OTHER THAN SOME HEAVY RAIN AT TIMES AND STANDING WATER IN LOW-LYING AREAS...IT SHOULD NOT POSE A FLOOD THREAT YET. RAIN TOTALS AFTER THIS FIRST WAVE COULD RANGE FROM A HALF INCH UP TO OVER AN INCH OF RAINFALL BY MIDDAY. OTHER THAN OFF AND ON RAIN...THE NEXT MAIN WAVE OF PRECIP WILL COME THROUGH LATE TONIGHT AS THE MAIN SFC LOW RIDES UP ALONG THE FRONT TONIGHT. THIS SHOULD SUPPORT THE BEST CHANCE AT FLOODING RAINS...WITH AID FROM THE RIGHT-ENTRANCE REGION OF 120-KT UPPER JET AND STRONG LLJ OF 60KTS. THUS WE COULD SEE ADDITIONAL RAINFALL AMOUNTS OF ANOTHER ONE TO MAYBE TWO INCHES. DO NOT SEE CONVECTION BEING A THREAT AS NAM AND GFS SFC AND ELEVATED INSTABILITY IS NON- EXISTENT FROM THE 00Z RUNS. THUS WILL REMOVE THUNDER WORDING. DESPITE LACK OF CONVECTION...THINK RAINFALL TOTALS COULD RANGE FROM 2-3 INCHES...WITH LOCALLY HIGHER AMOUNTS. THIS COULD LEAD TO MINOR FLOODING...WITH THE BEST CHANCE OCCURRING FOR SRN IN AND NRN KY LATE TONIGHT WITH THE SECOND WAVE OF PRECIP. THUS...FLOOD WATCH STILL SEEMS WARRANTED AND AM ACTUALLY INCLINED TO EXTEND IT TO 12Z MONDAY. MAY DEFER THIS TO DAY SHIFT THOUGH. FOR AVIATION CONCERNS...OTHER THAN VARIABLE LIFR CIGS AND VIS`S...WILL HAVE LLWS TONIGHT WITH STRONG 850MB JET. WILL HAVE QUITE THE TEMP GRADIENT FOR HIGHS TODAY...WITH LOW 60S SE TO AROUND 50 NW. ADDITIONALLY...WINDS MAY BE GUSTY TODAY AND TONIGHT...ESPECIALLY ACROSS THE SRN AND SERN CWA WITH GUSTS AROUND 20 MPH OR SO POSSIBLE. AL .LONG TERM (MONDAY THROUGH SATURDAY)... MONDAY AND TUESDAY... AT THE BEGINNING OF THIS PERIOD WE FIND AN UPPER LEVEL RIDGE PARKED OVER THE EASTERN GULF OF MEXICO AND FLORIDA WITH A TROUGH WORKING ACROSS THE UPPER MISSISSIPPI VALLEY. THE LAST WAVE OF LOW PRESSURE ALONG THE ARCTIC FRONT WILL MOVE FROM THE UPPER OHIO VALLEY ON ITS WAY TO THE NORTHEAST COAST. AN ASSOCIATED COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA DURING THE DAY MONDAY. IN ITS WAKE A NORTHERLY FLOW WILL BRING MORE WINTER LIKE TEMPERATURES INTO THE LOWER OHIO VALLEY. PRECIPITATION (HEAVY AT TIMES ACROSS THE SOUTHEAST MONDAY MORNING) WILL END AS THE COLD AIR ARRIVES ALTHOUGH THERE MAY BE SOME RAIN AND SNOW MIXED ACROSS SOUTHERN INDIANA MONDAY AFTERNOON. COLD AIR ADVECTION WILL CONTINUE MONDAY NIGHT INTO TUESDAY AND THE MODELS HINT AT SOME MOISTURE FROM LAKE MICHIGAN DROPPING SOUTH INTO THE REGION. WE WILL CONTINUE TO MENTION FLURRIES MONDAY NIGHT INTO TUESDAY. TEMPERATURES AT THE BEGINNING OF THIS FORECAST PERIOD (12Z) MONDAY WILL RANGE FROM AROUND 40 OVER THE NORTHWEST PORTION OF THE FORECAST AREA TO THE UPPER 50S ACROSS THE SOUTHEAST. TEMPERATURES WILL FALL THROUGH THE DAY. NORMAL LOW TEMPERATURES IN THE MID AND UPPER 20S MONDAY NIGHT WILL FEEL VERY COLD COMPARED TO THE RECENT WARM SPELL. TUESDAYS HIGHS WILL REACH THE MID 30S WITH LOWS TUESDAY NIGHT FALLING INTO THE UPPER TEENS AND LOW 20S. --JA WEDNESDAY THROUGH SATURDAY... MORE OR LESS OF A CONSENSUS FOR A SPLIT FLOW PATTERN SHAPING UP FOR THIS PERIOD. THE NORTHERLY BRANCH LOOKS TO BE THE STRONGEST AND THE CONTROLLING WEATHER FEATURE FOR OUR REGION. ONE OR TWO SYSTEMS ROTATING ESE ACROSS SRN CANADA INTO THE NORTHEASTERN U.S. DURING THIS TIME FRAME WOULD BRING BURSTS OF REINFORCING COLDER AND DRY AIR INTO THE REGION. ALL IN ALL...WE AGREE WITH THE HPC TRENDS FOR A MUCH NEEDED DRY PERIOD WITH TEMPS NEAR OR ONLY A FEW DEGREES ABOVE NORMAL. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ023>043-045>049-053>057- 061>067-070>078-081-082. IN...FLOOD WATCH THROUGH LATE TONIGHT FOR INZ076>079-083-084-089>092. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 640 AM EST SUN JAN 14 2007 .SHORT TERM.../TODAY THROUGH TUESDAY/ WENT WITH GFS SOLUTION FOR SHORT TERM. BASED ON CURRENT TRENDS... SLOWED DOWN EASTWARD PROGRESSION OF FRONT BY A FEW HOURS...CONFINING HIGHEST PRECIP CHANCES TO NORTHWEST COUNTIES OF CWA THIS MORNING. FRONT SHOULD EVENTUALLY MAKE ITS EASTWARD PUSH LATER THIS AFTERNOON INTO TONIGHT...AS A STRONG SHORT WAVE EJECTS OUT OF THE SOUTHERN PLAINS. WITH STRONG HIGH PRESSURE STILL SITTING OF THE SOUTHEASTERN UNITED STATES...FRONT WILL BE SLOW TO EXIT REGION. ANTICIPATING THAT FRONT WONT MOVE EAST OF JKL CWA UNTIL SOMETIME MONDAY NIGHT. LEFT IN FLOOD WATCH FOR NORTHWESTERN COUNTIES DUE TO PERSISTANT RAINS THERE. SOUTHERN HALF OF CWA HADNT SEEN NEARLY AS MUCH RAIN AS THE NORTHWEST...SO FLOODING IS NOT MUCH OF A CONCERN. WINDS AND DEWPOINTS WERE ALREADY IN GOOD SHAPE WITH ONLY A FEW MINOR TWEAKS MADE BASED UPON LATEST MODEL RUNS AND MOS GUIDANCE. MADE A FEW CHANGES TO SKY COVER FOR THE TODAY AND TONIGHT...MAINLY TO REFLECT SLOWER EASTWARD PROGRESS OF FRONT. POP FORECAST ALSO MODIFIED QUITE A BIT...WITH LOWER POPS INTRODUCED TO SOUTHERN HALF OF CWA AND A MUCH SLOWER ONSET OF MAIN PRECIPITATION EVENT. LOOKING FOR MAIN PUSH OF RAIN TO MOVE THROUGH THE CWA BEGINNING LATER TONIGHT THROUGH MONDAY NIGHT. SOME AREAS IN THE NORTHERN PORTION OF CWA COULD RECEIVE A COUPLE OF INCHES OF RAIN OUT THIS NEXT ROUND OF PRECIP. EVERYWHERE ELSE SHOULD RECEIVE LESS THAN AN INCH. COULD ALSO SEE SNOW SHOWERS LATE MONDAY NIGHT INTO TUESDAY...AS THE COLDEST AIR OF THE WINTER SEASON BEGINS TO FILTER INTO THE AREA BEHIND A DEPARTING COLD FRONT. FOR TEMPERATURES...WENT WITH A BLEND OF MAV/MET MOS ACROSS THE BOARD. WENT BELOW MOS FOR DAYTIME HIGHS...DUE TO EXTENSIVE CLOUD COVER...AND A BIT WARMER THAN MOS FOR OVERNIGHT LOWS SUNDAY NIGHT AND MONDAY NIGHT. WENT VERY CLOSE TO MEXMOS NUMBERS FOR WEDNESDAYS HIGHS. DEPENDING ON AMOUNT OF CLOUD COVER IN PLACE...A FEW AREAS COULD BE A BIT COOLER THAN MOS. .LONG TERM.../WEDNESDAY THROUGH SUNDAY/ MODELS SOLUTIONS FOR THE END OF THE WEEK HAVE CHANGED FROM THE PREVIOUS RUNS. GFS BRINGS MOISTURE...AND A SURFACE WAVE...UP FROM THE GULF OF MEXICO ON FRIDAY INTO SATURDAY. ECMWF HAS ALSO TRENDED FURTHER NORTH WITH THIS SYSTEM. DGEX AND NOGAPS KEEPS THIS FURTHER SOUTH. ALL MODELS SHOW AN APPROACHING COLD FRONT FOR LATER FRIDAY. INTRODUCED CHANCE POPS FOR FRIDAY INTO SATURDAY WITH ALL OF THIS IN MIND. ATTM...THINK THE COLD FRONT WILL LIKELY HAVE ENOUGH MOISTURE TO AT LEAST WARRANT CHANCE POPS FOR NOW. PRECIP TYPE IS IN QUESTION...WITH MARGINAL TEMPERATURES AT ALL LEVELS. FOR NOW...WENT WITH A MENTION OF RAIN AND SNOW. COLDER AIR WILL FILTER INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS THE COLD FRONT MOVES THROUGH. THERE IS STILL UNCERTAINTY IN THE LATER PORTION OF THE EXTENDED...SO THE FORECAST WILL LIKELY NEED TO BE FINE TUNED AS TIME GOES ON. && .AVIATION.../12Z TO 12Z/...UPDATED FRONTAL BOUNDARY STALLED JUST NORTHWEST OF THE AREA CONTINUES TO SEND WAVES OF SHOWERS NORTH OF INTERSTATE 64. NO REAL REASON FOR THE FRONT TO PUSH SOUTH...AND IN FACT IT WILL LIKELY WAFFLE BACK NORTH SOME TODAY AS LOW PRESSURE FORMS OVER THE LOWER MISSISSIPPI VALLEY AND THEN HEADS NORTH. THIS SHOULD RESULT IN AREA TAF SITES REMAINING VFR THROUGH THE DAY. ONE WRINKLE IN THIS THEORY IS A CONVECTIVELY INDUCED VORTICITY MAXIMUM WHICH SHOWS UP ON WATER VAPOR SATELLITE IMAGERY OVER MISSISSIPPI. RUC...AND TO SOME EXTENT THE NAM...PICK UP ON THIS FEATURE AND MOVE IT NORTHEAST ACROSS THE AREA THIS AFTERNOON. THIS MAY PROVIDE ENOUGH LIFT FOR SOME SHOWERS...BUT WILL MAINTAIN VFR CONDITIONS FOR NOW. CONDITIONS SHOULD FINALLY DETERIORATE LATER TONIGHT AS THE SURFACE WAVE MOVES NORTHEAST ACROSS THE WESTERN HALF OF THE STATE. HAVE DELAYED ONSET OF MVFR CIGS/VSBYS A FEW HOURS FROM EARLIER THINKING AS LATEST GUIDANCE IS A TOUCH SLOWER AND FARTHER WEST WITH THE SURFACE LOW. WINDS WILL ALSO BECOME GUSTY AFTER MIDNIGHT WITH SOME BORDERLINE LLWS AS MODELS DEVELOP A STRONG LOW LEVEL JET IN EXCESS OF 40 KT AROUND 2K FT AGL AND ABOVE. && .JKL WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH MONDAY AFTERNOON FOR KYZ044-050>052-058>060- 104-106-108. && $$ SHORT TERM...AR LONG TERM...WJM AVIATION...ABE ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 309 AM EST SUN JAN 14 2007 .SHORT TERM (TODAY AND TONIGHT)... CURRENTLY...A QUASI-STATIONARY FRONT IS ALIGNED ROUGHLY FROM SOUTH OF CINCINNATI...TO LOUISVILLE...TO MEMPHIS. SFC LOW PRESSURE WAVES RIDING ALONG THIS FRONT AND AMPLE MOISTURE HAVE BEEN RESPONSIBLE FOR THE RAINFALL OVER THE PAST 1-2 DAYS. RAINFALL TOTALS ACROSS THE CWA OVER THE PAST 24 HOURS HAVE RANGED FROM AROUND A TENTH OF AN INCH ACROSS THE SERN CWA TO ROUGHLY THREE- QUARTERS OF AN INCH ACROSS THE WNW. ANOTHER SFC WAVE OVER WRN TN IS HELPING PUMP MOISTURE NORTHWARD ALONG THE FRONT INTO OUR WRN CWA ATTM. THIS WILL BE THE FIRST OF TWO MAIN WAVES OF MOD-TO-HEAVY RAINFALL FOR THE CWA. BASED OFF THE 00Z NAM (WHICH HAS THE BEST HANDLE ON CURRENT RADAR IMAGERY)...THE TN SFC WAVE WILL RIDE ALONG THE FRONT WHICH WILL BE NEARLY PARALLEL TO THE OHIO RIVER. THUS THE HEAVIEST RAINFALL IS EXPECTED ALONG AND AROUND THE OHIO RIVER THROUGH THE MORNING HOURS AND PERHAPS INTO THE EARLY AFTERNOON HOURS. BOTH THE NAM AND RUC (AND WRF) THINK THAT OUR SERN CWA COULD GET BY TODAY WITH ONLY A FEW LIGHT RAIN SHOWERS. HAVE BACKED OFF ON POPS DOWN THERE TO ACCOUNT FOR THIS TREND. EVEN THOUGHT OF CANCELING THE WATCH ACROSS OUR FAR SERN CWA...BUT WE MAY SEE ENOUGH PRECIP WITH THE SECOND WAVE TO JUSTIFY IT. SOMETHING THE NEXT SHIFT WILL CERTAINLY HAVE TO CONSIDER THOUGH. WELL...THE FIRST WAVE OF POTENTIALLY HEAVY RAIN IS CURRENTLY CAUSING MINOR FLOODING PROBLEMS IN PAH`S CWA...BUT OTHER THAN SOME HEAVY RAIN AT TIMES AND STANDING WATER IN LOW-LYING AREAS...IT SHOULD NOT POSE A FLOOD THREAT YET. RAIN TOTALS AFTER THIS FIRST WAVE COULD RANGE FROM A HALF INCH UP TO OVER AN INCH OF RAINFALL BY MIDDAY. OTHER THAN OFF AND ON RAIN...THE NEXT MAIN WAVE OF PRECIP WILL COME THROUGH LATE TONIGHT AS THE MAIN SFC LOW RIDES UP ALONG THE FRONT TONIGHT. THIS SHOULD SUPPORT THE BEST CHANCE AT FLOODING RAINS...WITH AID FROM THE RIGHT-ENTRANCE REGION OF 120-KT UPPER JET AND STRONG LLJ OF 60KTS. THUS WE COULD SEE ADDITIONAL RAINFALL AMOUNTS OF ANOTHER ONE TO MAYBE TWO INCHES. DO NOT SEE CONVECTION BEING A THREAT AS NAM AND GFS SFC AND ELEVATED INSTABILITY IS NON- EXISTENT FROM THE 00Z RUNS. THUS WILL REMOVE THUNDER WORDING. DESPITE LACK OF CONVECTION...THINK RAINFALL TOTALS COULD RANGE FROM 2-3 INCHES...WITH LOCALLY HIGHER AMOUNTS. THIS COULD LEAD TO MINOR FLOODING...WITH THE BEST CHANCE OCCURRING FOR SRN IN AND NRN KY LATE TONIGHT WITH THE SECOND WAVE OF PRECIP. THUS...FLOOD WATCH STILL SEEMS WARRANTED AND AM ACTUALLY INCLINED TO EXTEND IT TO 12Z MONDAY. MAY DEFER THIS TO DAY SHIFT THOUGH. FOR AVIATION CONCERNS...OTHER THAN VARIABLE LIFR CIGS AND VIS`S...WILL HAVE LLWS TONIGHT WITH STRONG 850MB JET. WILL HAVE QUITE THE TEMP GRADIENT FOR HIGHS TODAY...WITH LOW 60S SE TO AROUND 50 NW. ADDITIONALLY...WINDS MAY BE GUSTY TODAY AND TONIGHT...ESPECIALLY ACROSS THE SRN AND SERN CWA WITH GUSTS AROUND 20 MPH OR SO POSSIBLE. AL .LONG TERM (MONDAY THROUGH SATURDAY)... MONDAY AND TUESDAY... AT THE BEGINNING OF THIS PERIOD WE FIND AN UPPER LEVEL RIDGE PARKED OVER THE EASTERN GULF OF MEXICO AND FLORIDA WITH A TROUGH WORKING ACROSS THE UPPER MISSISSIPPI VALLEY. THE LAST WAVE OF LOW PRESSURE ALONG THE ARCTIC FRONT WILL MOVE FROM THE UPPER OHIO VALLEY ON ITS WAY TO THE NORTHEAST COAST. AN ASSOCIATED COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA DURING THE DAY MONDAY. IN ITS WAKE A NORTHERLY FLOW WILL BRING MORE WINTER LIKE TEMPERATURES INTO THE LOWER OHIO VALLEY. PRECIPITATION (HEAVY AT TIMES ACROSS THE SOUTHEAST MONDAY MORNING) WILL END AS THE COLD AIR ARRIVES ALTHOUGH THERE MAY BE SOME RAIN AND SNOW MIXED ACROSS SOUTHERN INDIANA MONDAY AFTERNOON. COLD AIR ADVECTION WILL CONTINUE MONDAY NIGHT INTO TUESDAY AND THE MODELS HINT AT SOME MOISTURE FROM LAKE MICHIGAN DROPPING SOUTH INTO THE REGION. WE WILL CONTINUE TO MENTION FLURRIES MONDAY NIGHT INTO TUESDAY. TEMPERATURES AT THE BEGINNING OF THIS FORECAST PERIOD (12Z) MONDAY WILL RANGE FROM AROUND 40 OVER THE NORTHWEST PORTION OF THE FORECAST AREA TO THE UPPER 50S ACROSS THE SOUTHEAST. TEMPERATURES WILL FALL THROUGH THE DAY. NORMAL LOW TEMPERATURES IN THE MID AND UPPER 20S MONDAY NIGHT WILL FEEL VERY COLD COMPARED TO THE RECENT WARM SPELL. TUESDAYS HIGHS WILL REACH THE MID 30S WITH LOWS TUESDAY NIGHT FALLING INTO THE UPPER TEENS AND LOW 20S. --JA WEDNESDAY THROUGH SATURDAY... MORE OR LESS OF A CONSENSUS FOR A SPLIT FLOW PATTERN SHAPING UP FOR THIS PERIOD. THE NORTHERLY BRANCH LOOKS TO BE THE STRONGEST AND THE CONTROLLING WEATHER FEATURE FOR OUR REGION. ONE OR TWO SYSTEMS ROTATING ESE ACROSS SRN CANADA INTO THE NORTHEASTERN U.S. DURING THIS TIME FRAME WOULD BRING BURSTS OF REINFORCING COLDER AND DRY AIR INTO THE REGION. ALL IN ALL...WE AGREE WITH THE HPC TRENDS FOR A MUCH NEEDED DRY PERIOD WITH TEMPS NEAR OR ONLY A FEW DEGREES ABOVE NORMAL. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ023>043-045>049-053>057- 061>067-070>078-081-082. IN...FLOOD WATCH THROUGH LATE TONIGHT FOR INZ076>079-083-084-089>092. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 852 PM EST MON JAN 15 2007 .UPDATE/SHORT TERM /REST OF TONIGHT THROUGH TUESDAY/... MADE SMALL ADJUSTMENTS SUCH AS RAISING WIND GUST SPEEDS TO 25-30 MPH BASED ON RECENT SURFACE DATA AND NAM-WRF AND RUC MODEL FORECAST SOUNDINGS SHOWING SUCH GUSTS OCCURRING IN THE WAKE OF THE COLD FRONTAL PASSAGE. THE POST FRONTAL LOW LEVEL INSTABILITY COUPLED WITH GREAT LAKES MOISTURE WILL GENERATE SNOW SHOWERS LATE TONIGHT AND TUESDAY. STILL LOOKS LIKE MOST LOCATIONS GET AN INCH OR LESS WITH I-80 CORRIDOR AND MOUNTAINS TOPPING NEAR 3 INCHES, BEFORE CONDITIONS STABILIZE TUESDAY NIGHT. WILL UPDATE SPECIAL WEATHER STATEMENT REGARDING IMPENDING TRAVEL HAZARDS. EXPECT MUDSLIDES AND PONDED WATER HAZARDS TO BEGIN ABATING, BUT EXPECTED SUBFREEZING TEMPERATURES BY TUESDAY DAWN CAN CAUSE WET SURFACES TO TURN ICY. SNOW SHOWERS CAN CAUSE SNOW COVERED ROADS AND SLIPPERY SPOTS DAYTIME TUESDAY. && .PREV DISCUSSION... /ISSUED 355 PM EST MON JAN 15 2007/ SHORT TERM /TONIGHT AND TUESDAY/... COLD FRONT WILL MOVE EAST ACROSS RIDGES BY EARLY EVENING WITH RAIN ENDING AS DRIER AIR SWEEPS INTO REGION. MUCH COLDER AIR WILL THEN MOVE IN TONIGHT AS LOW PRESSURE HEADS NORTHEAST TOWARD NEW ENGLAND AND NORTHWEST FLOW DEVELOPS. 850MB TEMPS TO -15C COMING ACROSS LAKES WILL BRING SOME ACCUMULATION TO NORTHERN COUNTIES AND IN THE RIDGES. SURFACE HIGH WILL TRY TO BRING IN ANTICYCLONIC FLOW LATER TUESDAY AND AMOUNTS LOOK TO BE IN THE 1-3 INCHES RANGE OVER 24 HOURS AND UNDER ADVISORY CRITERIA. MUCH COLDER WITH MAX TEMPS TUE ONLY A DEGREE OR TWO ABOVE TONIGHTS MINS IF THAT. LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... NORTHWEST FLOW SHOULD CONTINUE THROUGH WEDNESDAY MORNING WITH SCATTERED SNOW SHOWERS ACCUMULATING ANOTHER INCH MAINLY ACROSS THE NORTH AND ALONG THE RIDGES TUESDAY NIGHT. SURFACE HIGH WILL SLIDE EASTWARD FROM THE MID MS VALLEY ACROSS THE OHIO VALLEY ON WEDNESDAY...AND OFF THE EAST COAST BY THURSDAY AFTERNOON. THIS WILL PROVIDE A BREAK FROM ANY PRECIPITATION THROUGH EARLY THURSDAY NIGHT. BROAD UPPER TROUGH WILL MOVE EAST ACROSS THE GREAT LAKES REGION FRIDAY AND SATURDAY. ASSOCIATED COLD FRONT EXPECTED TO CROSS FORECAST AREA ON FRIDAY WITH NORTHWEST FLOW SETTING UP BEHIND FRONT. WILL INCLUDE CHANCE OF SNOW SHOWERS IN FORECAST FROM LATE THURSDAY NIGHT INTO SATURDAY. EXPECT DRY CONDITIONS ON SUNDAY WITH NEXT SYSTEM BRINGING A CHANCE OF RAIN AND SNOW SHOWERS LATE MONDAY. AVIATION... FRONT WILL PUSH ACROSS TERMINALS EARLY EVENING WITH RAIN ENDING AND GENERAL IMPROVEMENT TO MVFR CIGS AND VFR VSBY AS LOW LEVELS DRY OUT. COLD AIR MOVING ACROSS LAKES WILL BRING SNOW SHOWERS LATER TONIGHT AND ESPECIALLY TUESDAY WITH NORTHWEST FLOW. EXPECT SOME MVFR CIGS AND VSBY IN SNOW SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 11 md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 749 PM EST SUN JAN 14 2007 .UPDATE/SHORT TERM /REST OF TONIGHT/... ADDED MENTION OF AREAS OF FOG INTO MONDAY MORNING...AS LOW LEVELS ARE SATURATED WITH RAIN CONTINUING TO FALL...AND WINDS ARE LIGHT. ALSO DELAYED ONSET OF HEAVIER RAIN ACROSS THE UPPER OHIO VALLEY UNTIL AFTER MIDNIGHT...BASED ON LATEST RUC MODEL AND RECENT RADAR DATA. MAINTAINING FLOOD WATCH AS IS. && .PREV DISCUSSION... /ISSUED 245 PM EST SUN JAN 14 2007/ SHORT TERM /TONIGHT THROUGH MONDAY/... RAIN DRIZZLE AND FOG INTO TONIGHT AS SURFACE WAVE APPROACHES FROM SOUTHERN PLAINS AND MOVES ALONG BOUNDARY DRAPED ACROSS REGION. EXPECT RAIN TO INTENSIFY TONIGHT WITH HIGHEST AMOUNTS ALONG AND WEST OF LOW TRACK INTO SOUTHWEST PA. FLOOD WATCH FOR AREA FROM PITTSBURGH EAST ACROSS CWA AS HEAVIEST RAIN WILL OCCUR LATER TONIGHT INTO THE FIRST HALF OF MONDAY. TEMPERATURES WILL BE TRICKY AS FRONT TRIES TO SHIFT NORTH LATER TONIGHT AND IS PUSHED NORTH BY SURFACE WAVE MONDAY. WILL HAVE STEADY OR SLOWLY RISING TEMPS TONIGHT AND PUSH MAX TEMPS UP SIGNIFICANTLY FROM PREVIOUS FORECAST FOR MONDAY CLOSER TO MODEL GUIDANCE. LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... CLOSED SURFACE LOW MOVES THROUGH THE AREA DURING THE DAY ON MONDAY WITH COLDER AIR MOVING IN FROM THE NORTHWEST MONDAY NIGHT. COLD NORTHWEST FLOW COMING IN OVER THE RELATIVELY WARMER LAKE ERIE WILL BRING A CHANCE OF SNOW SHOWERS FOR MONDAY NIGHT INTO TUESDAY. THIS RUN IS THE SAME AS LAST AND BY 06Z TUESDAY H8 TEMP MINUS 8 AT PIT TO MINUS 10 ALONG THE ERIE LAKESHORE. LAKE ERIE TEMP IS PLUS 2. DRY TUESDAY NIGHT THROUGH THURSDAY NIGHT UNDER HIGH PRESSURE. CHANCE PCPN FRIDAY AND FRIDAY NIGHT AS TROUGH SWINGS THROUGH FROM THE NORTHWEST. SATURDAY AND SATURDAY NIGHT HIGH PRESSURE COVERS THE AREA. DURING THE DAY ON SUNDAY ANOTHER WEAK TROUGH APPROACHES FROM THE NORTHWEST. AVIATION /20Z-18Z/... STATIONARY FRONT WILL REMAIN ALONG THE OHIO RIVER TODAY WITH NEXT SURFACE WAVE TRACKING ALONG BOUNDARY INTO WESTERN PA BY LATE TONIGHT. WIDESPREAD IFR CONDITIONS ALONG AND NORTH OF FRONT BUT AS FRONT BEGINS TO SHIFT NORTH LATER TONIGHT INTO MONDAY MVFR WILL BEGIN TO SHIFT NORTH BEHIND FRONT. PERIODS OF RAIN AND DRIZZLE THROUGH THE PERIOD. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OHZ039>041-048>050- 057>059-068-069. PA...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR PAZ007-013-020-021- 029-031. WV...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR WVZ001>004-012. && $$ 11 md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 952 PM EST MON JAN 15 2007 .UPDATE... THE AREA OF LIGHT SNOW OVER SOUTHERN LOWER MICHIGAN WAS WEAKENING AS THE MID LEVEL DEFORMATION SHEARED APART WHILE SLIDING EASTWARD. EXPECT THIS TREND TO CONTINUE AND LEAVE BEHIND COLD NORTHERLY LOW LEVEL FLOW THAT WILL HEIGHTEN LAKE EFFECT POTENTIAL IN THE THUMB FOR A FEW HOURS. THE LATEST OBSERVATIONS SHOWED A NICE AREA OF WIND CONVERGENCE COMING INTO THE THUMB BETWEEN GRAVELLY SHOAL AND HARBOR BEACH. COMBINE THIS WITH COLD ADVECTION TAKING 850 MB TEMPS DOWN TO ABOUT -15C BY 06Z AND EQUILIBRIUM LEVELS RISING TO ABOUT 750MB/7000 FEET AND THE INITIAL SET UP LOOKS GOOD FOR OUR GOING FORECAST. ONE TO 3 INCHES APPEARS ON TARGET CONSIDERING THE BRIEF NATURE OF THE EVENT WITH THE WINDS TURNING TOWARD THE NW BY 09Z DRIVING LAKE EFFECT WELL OFF SHORE BY 12Z. OUR FORECAST UPDATE WILL BE ISSUED CLOSER TO MIDNIGHT TO LOWER POPS OVER INLAND AREAS DURING THE OVERNIGHT ONCE THE LIGHT SYSTEM SNOW DIMINISHES ADEQUATELY. WE WILL ALSO REVISIT ACCUMULATION IN THE THUMB BASED ON THE LATEST RADAR AND WIND TRENDS. && .PREV DISCUSSION...ISSUED 643 PM EST MON JAN 15 2007 AVIATION... MVFR WILL BE THE PREVAILING AVIATION CONDITION TONIGHT THROUGH EARLY AFTERNOON ON TUESDAY, TRENDING TOWARD VFR DURING THE LATE AFTERNOON. THE LATEST OBSERVATIONS SHOWED AN AREA OF LIGHT SNOW MOVING THROUGH SOUTHERN LOWER MICHIGAN THIS EVENING. THIS WILL PROGRESS EASTWARD AND STAY MOSTLY NORTH OF DETROIT WHILE WEAKENING. MVFR VISIBILITY IN LIGHT SNOW WILL COVER THE FNT AND MBS TERMINALS FOR A FEW MORE HOURS THIS EVENING. VISIBILITY WILL THEN BECOME VFR AFTER MIDNIGHT WITH A BROKEN MVFR CEILING. SOME BRIEF PERIODS OF VFR CEILING WILL BE POSSIBLE, ESPECIALLY AT MBS AND FNT, AS THE WINDS BECOME MORE NEUTRAL FROM THE NORTH. ANY BREAKS WILL THEN FILL BACK IN DURING THE DAYLIGHT HOURS OF TUESDAY LASTING THROUGH ABOUT MID AFTERNOON. PREV DISCUSSION...ISSUED 329 PM EST MON JAN 15 2007 SHORT TERM...TONIGHT AND TUESDAY WITH OUR RECENT STORM TRACKING EAST OF THE GREAT LAKES...RESIDUAL DEFORMATION AXIS OF SNOW WILL MOVE ACROSS THE REGION THIS EVENING. CROSS SECTIONS NICELY DEPICT THIS DEFORMATION ZONE CENTERED BETWEEN 600-700MB WITH VISIBILITIES UNDER THE BAND OF SNOW DROPPING TO LESS THAN 1 MILE. IN FACT...SOME LAKE HURON CONTRIBUTION IS NOTED WITH A NARROW BAND OF SNOW COMING DOWN ACROSS SAGINAW BAY INTO MBS WITH 1/4 MILE VISIBILITY. LATEST RUC INCLUDING THE 12Z MODEL SUITE SUGGEST THE 1000-850MB WIND WILL BACK TOWARD THE NORTH THIS EVENING AS THIS DEFORMATION AXIS SWINGS SOUTH-SOUTHEAST ACROSS THE STATE. SPECIFIC HUMIDITIES ARE RUNNING AROUND 1 G/KG AND ACCUMULATIONS COULD ADD UP TO ANOTHER 1 INCH NORTH OF M59 THIS EVENING. FURTHER SOUTH...WITH THE BOUNDARY LAYER BECOMING MORE NORTHERLY...EXPECT SOME DOWNSLOPING INFLUENCES TO REDUCE THE SNOWFALL AMOUNTS AND DEFORMATION AXIS WEAKENING AS THE SURFACE TROUGH AND UPPER LEVEL TROUGH SWING SOUTHEAST OF THE STATE. THEN THE REAL COLD ADVECTION TAKES SHAPE TONIGHT WITH CONCERN SHIFTING TOWARD LAKE EFFECT SNOW FOR PORTIONS OF THE THUMB. BOTH THE NAM AND GFS ARE IN RATHER GOOD AGREEMENT WITH THE 1000-850MB FLOW WHICH IS RATHER PERSISTENT (360 DEGREES) FOR MOST OF THE NIGHT. TOWARD 09Z-12Z...FLOW BACKS A LITTLE MORE TAKING THE BAND OFFSHORE BUT STILL TOUCHING THE M10 CORRIDOR IN HURON COUNTY. INVERSION HEIGHTS CLIMB...PER BUFKIT PROFILES...FROM NEAR 850MB TO BETWEEN 800-750MB WITH LAKE INDUCED CAPES CLIMBING TOWARD 300 J/KG AND LAKE DELTA T/S INTO THE MIDDLE TEENS CELSIUS. 925MB CONVERGENCE AND OMEGA FIELDS LOOK RATHER IMPRESSIVE ACROSS HURON...SANILAC AND TOUCHING NORTHEAST ST CLAIR COUNTY OVERNIGHT SO ADDITIONAL SNOWFALL IS EXPECTED. LOCAL DECISION TREE SUGGESTS ANOTHER 2-4"/12HRS BUT WITH THE BAND MOVING OFFSHORE...WILL CUT THOSE VALUES TO ANOTHER 1-3" AND MENTION BRIEF PERIODS OF HEAVY SNOW IN THE FORECAST/GRIDS. WEATHER DOES QUIET DOWN ON TUESDAY WITH A COLD NORTHERLY FLOW AND MOISTURE DECREASING. THIS SHOULD ALLOW FOR SOME SUNNY BREAKS YET THAT COULD HELP STEEPEN THE LOW LEVEL LAPSE RATES...AND WOULD NOT BE SURPRISED TO SEE SOME LIGHT SNOW SHOWERS MOVING ACROSS THE CWA. WILL KEEP THE LOW POPS FOR MOST AREAS AWAY FROM LAKE HURON...AS LAKE BAND COULD STILL IMPACT THE M10 CORRIDOR IN HURON COUNTY. TEMPERATURES WILL BE QUITE CHILLY (OR SEASONABLE) TONIGHT AND TUESDAY WITH LOWS TONIGHT DROPPING BACK INTO THE TEENS. ON TUESDAY WITH 850MB TEMPS INTO THE NEGATIVE MID TEENS...WE WILL BE LUCKY TO TOUCH 30F. LONG TERM... MODIFYING TREND WEDNESDAY AND THURSDAY BEFORE ANOTHER SURGE OF ARCTIC AIR ARRIVES BY FRIDAY. MEDIUM RANGE MODELS (12Z EUROPEAN/CANADIAN GLOBAL/GFS) IN DECENT AGREEMENT THROUGH THE FIRST HALF OF THE WEEKEND. AMPLIFIED UPPER LEVEL RIDGE TO BUILD INTO THE CENTRAL GREAT LAKES ON WEDNESDAY. TUESDAY NIGHT IS SHAPING UP TO BE THE COLDEST NIGHT OF THE SEASON THUS FAR AS 1040+ MB HIGH SETS UP OVER THE NORTHERN OHIO VALLEY WEDNESDAY MORNING. HOWEVER...RELATIVELY WARM GROUND AND LACK OF SIGNIFICANT SNOW DEPTH OVER MUCH OF SOUTHEAST MICHIGAN SHOULD FACTOR IN. WENT FAIRLY CLOSE TO GFS MOS GUIDANCE...UPPER SINGLE NUMBERS TO LOWER TEENS. IF THIS WAS A MORE TYPICAL WINTER...WOULD HAVE EXPECTED MINS DOWN AROUND ZERO. TRAILING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA IS FORECASTED TO EJECT OFF TO THE NORTHEAST...AS MORE VIGOROUS UPPER WAVES OVER THE GULF OF ALASKA AND ALASKA EVENTUALLY CARVE OUT ANOTHER TROUGH OVER THE NORTH CENTRAL CONUS ON THURSDAY. SOME TIMING DIFFERENCES WITH THE SOUTHERN WAVE...ALONG WITH MEAGER MOISTURE INDICATED BY MODELS ON THURSDAY. NONE-THE-LESS...IT IS A DECENT WAVE AND POSSIBLE HELP FROM LAKE MICHIGAN...PREFER TO CARRY A LOW CHANCE OF LIGHT SNOW OR FLURRIES BY THURSDAY AFTERNOON. THERE IS SOME SEMBLANCE OF AN 850-700 MB THETA-E RIDGE/WEAK MOISTURE TRANSPORT MOVING THROUGH AS WELL. A LITTLE BETTER CHANCE OF SNOW SHOWERS THURSDAY NIGHT AND ESPECIALLY FRIDAY WITH COLD FRONT SLIDING THROUGH THURSDAY NIGHT AND LAKE EFFECT LIKELY KICKING IN BY FRIDAY AS 850 MB TEMPS DROP TO -16 TO -18 C. ARCTIC AIRMASS LOOKS TO BE SLOW TO PUSH EAST ON SATURDAY...WITH A CONTINUED CHANCE OF SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE/AVIATION...BT SHORT TERM...BGM LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 643 PM EST MON JAN 15 2007 .AVIATION... MVFR WILL BE THE PREVAILING AVIATION CONDITION TONIGHT THROUGH EARLY AFTERNOON ON TUESDAY, TRENDING TOWARD VFR DURING THE LATE AFTERNOON. THE LATEST OBSERVATIONS SHOWED AN AREA OF LIGHT SNOW MOVING THROUGH SOUTHERN LOWER MICHIGAN THIS EVENING. THIS WILL PROGRESS EASTWARD AND STAY MOSTLY NORTH OF DETROIT WHILE WEAKENING. MVFR VISIBILITY IN LIGHT SNOW WILL COVER THE FNT AND MBS TERMINALS FOR A FEW MORE HOURS THIS EVENING. VISIBILITY WILL THEN BECOME VFR AFTER MIDNIGHT WITH A BROKEN MVFR CEILING. SOME BRIEF PERIODS OF VFR CEILING WILL BE POSSIBLE, ESPECIALLY AT MBS AND FNT, AS THE WINDS BECOME MORE NEUTRAL FROM THE NORTH. ANY BREAKS WILL THEN FILL BACK IN DURING THE DAYLIGHT HOURS OF TUESDAY LASTING THROUGH ABOUT MID AFTERNOON. && .PREV DISCUSSION...ISSUED 329 PM EST MON JAN 15 2007 SHORT TERM...TONIGHT AND TUESDAY WITH OUR RECENT STORM TRACKING EAST OF THE GREAT LAKES...RESIDUAL DEFORMATION AXIS OF SNOW WILL MOVE ACROSS THE REGION THIS EVENING. CROSS SECTIONS NICELY DEPICT THIS DEFORMATION ZONE CENTERED BETWEEN 600-700MB WITH VISIBILITIES UNDER THE BAND OF SNOW DROPPING TO LESS THAN 1 MILE. IN FACT...SOME LAKE HURON CONTRIBUTION IS NOTED WITH A NARROW BAND OF SNOW COMING DOWN ACROSS SAGINAW BAY INTO MBS WITH 1/4 MILE VISIBILITY. LATEST RUC INCLUDING THE 12Z MODEL SUITE SUGGEST THE 1000-850MB WIND WILL BACK TOWARD THE NORTH THIS EVENING AS THIS DEFORMATION AXIS SWINGS SOUTH-SOUTHEAST ACROSS THE STATE. SPECIFIC HUMIDITIES ARE RUNNING AROUND 1 G/KG AND ACCUMULATIONS COULD ADD UP TO ANOTHER 1 INCH NORTH OF M59 THIS EVENING. FURTHER SOUTH...WITH THE BOUNDARY LAYER BECOMING MORE NORTHERLY...EXPECT SOME DOWNSLOPING INFLUENCES TO REDUCE THE SNOWFALL AMOUNTS AND DEFORMATION AXIS WEAKENING AS THE SURFACE TROUGH AND UPPER LEVEL TROUGH SWING SOUTHEAST OF THE STATE. THEN THE REAL COLD ADVECTION TAKES SHAPE TONIGHT WITH CONCERN SHIFTING TOWARD LAKE EFFECT SNOW FOR PORTIONS OF THE THUMB. BOTH THE NAM AND GFS ARE IN RATHER GOOD AGREEMENT WITH THE 1000-850MB FLOW WHICH IS RATHER PERSISTENT (360 DEGREES) FOR MOST OF THE NIGHT. TOWARD 09Z-12Z...FLOW BACKS A LITTLE MORE TAKING THE BAND OFFSHORE BUT STILL TOUCHING THE M10 CORRIDOR IN HURON COUNTY. INVERSION HEIGHTS CLIMB...PER BUFKIT PROFILES...FROM NEAR 850MB TO BETWEEN 800-750MB WITH LAKE INDUCED CAPES CLIMBING TOWARD 300 J/KG AND LAKE DELTA T/S INTO THE MIDDLE TEENS CELSIUS. 925MB CONVERGENCE AND OMEGA FIELDS LOOK RATHER IMPRESSIVE ACROSS HURON...SANILAC AND TOUCHING NORTHEAST ST CLAIR COUNTY OVERNIGHT SO ADDITIONAL SNOWFALL IS EXPECTED. LOCAL DECISION TREE SUGGESTS ANOTHER 2-4"/12HRS BUT WITH THE BAND MOVING OFFSHORE...WILL CUT THOSE VALUES TO ANOTHER 1-3" AND MENTION BRIEF PERIODS OF HEAVY SNOW IN THE FORECAST/GRIDS. WEATHER DOES QUIET DOWN ON TUESDAY WITH A COLD NORTHERLY FLOW AND MOISTURE DECREASING. THIS SHOULD ALLOW FOR SOME SUNNY BREAKS YET THAT COULD HELP STEEPEN THE LOW LEVEL LAPSE RATES...AND WOULD NOT BE SURPRISED TO SEE SOME LIGHT SNOW SHOWERS MOVING ACROSS THE CWA. WILL KEEP THE LOW POPS FOR MOST AREAS AWAY FROM LAKE HURON...AS LAKE BAND COULD STILL IMPACT THE M10 CORRIDOR IN HURON COUNTY. TEMPERATURES WILL BE QUITE CHILLY (OR SEASONABLE) TONIGHT AND TUESDAY WITH LOWS TONIGHT DROPPING BACK INTO THE TEENS. ON TUESDAY WITH 850MB TEMPS INTO THE NEGATIVE MID TEENS...WE WILL BE LUCKY TO TOUCH 30F. LONG TERM... MODIFYING TREND WEDNESDAY AND THURSDAY BEFORE ANOTHER SURGE OF ARCTIC AIR ARRIVES BY FRIDAY. MEDIUM RANGE MODELS (12Z EUROPEAN/CANADIAN GLOBAL/GFS) IN DECENT AGREEMENT THROUGH THE FIRST HALF OF THE WEEKEND. AMPLIFIED UPPER LEVEL RIDGE TO BUILD INTO THE CENTRAL GREAT LAKES ON WEDNESDAY. TUESDAY NIGHT IS SHAPING UP TO BE THE COLDEST NIGHT OF THE SEASON THUS FAR AS 1040+ MB HIGH SETS UP OVER THE NORTHERN OHIO VALLEY WEDNESDAY MORNING. HOWEVER...RELATIVELY WARM GROUND AND LACK OF SIGNIFICANT SNOW DEPTH OVER MUCH OF SOUTHEAST MICHIGAN SHOULD FACTOR IN. WENT FAIRLY CLOSE TO GFS MOS GUIDANCE...UPPER SINGLE NUMBERS TO LOWER TEENS. IF THIS WAS A MORE TYPICAL WINTER...WOULD HAVE EXPECTED MINS DOWN AROUND ZERO. TRAILING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA IS FORECASTED TO EJECT OFF TO THE NORTHEAST...AS MORE VIGOROUS UPPER WAVES OVER THE GULF OF ALASKA AND ALASKA EVENTUALLY CARVE OUT ANOTHER TROUGH OVER THE NORTH CENTRAL CONUS ON THURSDAY. SOME TIMING DIFFERENCES WITH THE SOUTHERN WAVE...ALONG WITH MEAGER MOISTURE INDICATED BY MODELS ON THURSDAY. NONE-THE-LESS...IT IS A DECENT WAVE AND POSSIBLE HELP FROM LAKE MICHIGAN...PREFER TO CARRY A LOW CHANCE OF LIGHT SNOW OR FLURRIES BY THURSDAY AFTERNOON. THERE IS SOME SEMBLANCE OF AN 850-700 MB THETA-E RIDGE/WEAK MOISTURE TRANSPORT MOVING THROUGH AS WELL. A LITTLE BETTER CHANCE OF SNOW SHOWERS THURSDAY NIGHT AND ESPECIALLY FRIDAY WITH COLD FRONT SLIDING THROUGH THURSDAY NIGHT AND LAKE EFFECT LIKELY KICKING IN BY FRIDAY AS 850 MB TEMPS DROP TO -16 TO -18 C. ARCTIC AIRMASS LOOKS TO BE SLOW TO PUSH EAST ON SATURDAY...WITH A CONTINUED CHANCE OF SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...BT SHORT TERM...BGM LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST MON JAN 15 2007 .DISCUSSION... MAIN FCST CONCERNS ARE LES TRENDS TONIGHT INTO TUE AND SNOW/LES POTENTIAL WITH NEXT MID LVL TROF AND COLD FRONT THU INTO FRI. WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROF FROM NRN QUEBEC THROUGH NRN MN AND THE CNTRL PLAINS TO THE SW CONUS AND RDG FROM THE PAC NW INTO NRN ALBERTA. AN INCREASINGLY SHEARED SHRTWV WAS SLIDING E THROUGH E UPR MI AND ERN WI. AT THE SFC...BRISK NRLY WINDS PREVAILED ACRS THE WRN GRT LAKES BTWN LOW PRES OVER NY AND A RDG FROM NRN ONTARIO INTO THE NRN PLAINS. RADARS INDICATED THAT LIGHT SNOW SUPPORTED BY 700-300 QVECTOR AHEAD OF THE MID LVL TROF WAS DIMINISHING BUT VSBYS REMAINED GENERALLY IN THE 2-4SM RANGE FROM NRN WI INTO SRN UPR MI AT 20Z. MULTIPLE WIND PARALLEL LES BANDS INTO NRN UPR MI WERE BRINGING OCNLY HEAVY SNOW ESPECIALLY INTO THE HIGHER TERRAIN. BANDS WERE SHIFTING THOUGH AS WINDS BACK FROM NNE TO N. PLENTY OF INSTABILITY/MOISTURE AVBL FOR LES AS 17Z KSAW/KCMX TAMDAR SNDGS INDICATED DEEP MOISTURE OVER THE AREA WITH -19C/-21C AT TOP OF 6K FT INVERSION AND 850 MB TEMPS OF -17C/-20C. UPSTREAM...VERY DRY ARCTIC AIR WAS FILTERING INTO N AND W LK SUPERIOR WHERE SFC DEWPOINTS WERE -10F TO -20F. AS A RESULT...LAKE CLOUDS WERE DEVELOPING CLOSER TO THE SOUTH SHORE OF THE LAKE. TONIGHT...EXPECT THE REMAINING LIGHT SNOW OVER S UPR MI TO TAPER OFF TO SCT LIGHT SNOW SHOWERS OR FLURRIES EARLY THIS EVENING...PER RADAR AND SATELLITE TRENDS. SO...THE SNOW ADVY OVER THE SOUTH WILL BE DROPPED. GIVEN THE CLOUD TRENDS OVER THE WEST AND UPSTREAM 1000-850 RH IN THE 30-50 PCT RANGE...THE LES SHOULD ALSO DIMINISH THIS EVENING. SINCE SOME MINOR ACCUMULATIONS OF AN INCH OR TWO ARE STILL POSSIBLE WILL LEAVE THE WARNING/ADVISORIES INTACT. THE LONGER FETCH WILL HELP SUSTAIN THE LES INTO N CNTRL AND E UPR MI EVEN WITH THE DEPARTURE OF THE 850-700 MB MOISTURE. MDLS ARE CONSISTENT WITH THE GRADUAL BACKING TREND WHICH WILL MOVE THE BEST LOW LVL CONV FROM MARQUETTE COUNTY TO ALGER/LUCE COUNTIES OVERNIGHT. SINCE LES INTENSITY IS EXPECTED TO DIMINISH BY LATE THIS EVENING...NO ADJUSTMENT TO 04Z WARNING/ADVISORY EXPIRATIONS EWAS MADE. ADDITIONAL ACCUMULATIONS WILL BE GREATEST THIS EVENING IN THE 1-4 INCH RANGE WITH ONLY 1-2 INCH AMOUNTS...MAINLY E OF MARQUETTE AFT 04Z. TUE...NW FLOW LES WILL CONTINUE WITH ACCUMULATIONS EXPECTED MAINLY OVER THE ERN CWA. ALTHOUGH 850 TEMP TEMPS WILL REMAIN NEAR -20C...THE RELATIVELY SHALLOW COLD AIR(INVERSION HEIGHT NEAR 4K FT) WILL NOT BE FAVORABLE FOR SNOW GROWTH OR FORMATION OF STRONGER DOMINANT BANDS. SO...EXPECT AMOUNTS TO REMAIN IN THE 2-4 INCH RANGE WITH THE GREATEST AMOUNTS BTWN MUNISING AND NEWBERRY. THE SHORTER FETCH INTO W UPR MI WILL LEAD TO ONLY MINOR ACCUMULATIONS. WINDS WILL BACK SWRLY TUE NIGHT...PUSHING ANY REMAINING LES OFFSHORE WITH ONLY MINOR ADDITIONAL ACCUMULATIONS OVER THE FAR NE CWA. WED...BRISK SW FLOW AND WAA DEVELOPING BTWN THE DEPARTING SFC RDG AND TROF DEVELOPING OVER THE PLAINS WILL BRING A QUICK WARMUP WITH TEMPS AOA NORMAL INTO THE MID AND UPPER 20S ALONG WITH PARTLY TO MOSTLY SUNNY SKIES. THU INTO FRI...THE GFS TIMING LAGGED THE PREFERRED UKMET/ECMWF/CANADIAN WITH THE NEXT MID LVL TROF MOVING INTO THE AREA. ALTHOUGH LITTLE MOISTURE WILL BE AVAILABLE WITH THE SYSTEM AND THE GFS IS LIKELY A BIT GENEROUS WITH THE QPF...THE TROF STRENGTH/DYNAMICS JUSTIFY -SN CHANCES ACRS THE CWA. LES WILL RETURN IN THE WAKE OF THE SYSTEM AS THE ECMWF/GFS SHOW CAA DROPPING 850 MB TEMPS INTO THE -16C TO -20C BEHIND THE COLD FRONT. NW FLOW FAVORED AREAS SHOULD SEE BEST CHANCE FOR SIGNIFICANT ACCUMULATIONS ALTHOUGH THE GFS HINTS AT POSSIBILITY OF WINDS VEERING MORE NRLY FOR A TIME FRI AS A SECONDARY TROF AND WEAK SHRTWV MOVES THROUGH. SAT THROUGH MON...GENERALLY FOLLOWING THE HPC PREFERRED 00Z ECMWF/NCEP ENS MEAN WOULD SHIFT LES FOCUS TO W FLOW FAVORED LOCATIONS BY SAT WITH LES DIMINISHING SUN AS 850 TEMPS CLIMB ABOVE -10C. AND WINDS BECOME VARIABLE AND E LATE SUN. UNCERTAINTY INCREASES SIGNIFICANTLY...PER MDLS AND ENSEMBLES SPREAD...BY MON WITH POSITION AND STRENGTH OF THE NEXT SIGNIFICANT MID LVL TROF AND SFC LOW WHICH BRINGS CHANCE OF SNOW ACRS THE CWA. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 11 PM EST THIS EVENING FOR MIZ001>004-006-084-085. LAKE EFFECT SNOW WARNING UNTIL 11 PM EST /10 PM CST/ THIS EVENING FOR MIZ005-009. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 329 PM EST MON JAN 15 2007 .SHORT TERM...TONIGHT AND TUESDAY WITH OUR RECENT STORM TRACKING EAST OF THE GREAT LAKES...RESIDUAL DEFORMATION AXIS OF SNOW WILL MOVE ACROSS THE REGION THIS EVENING. CROSS SECTIONS NICELY DEPICT THIS DEFORMATION ZONE CENTERED BETWEEN 600-700MB WITH VISIBILITIES UNDER THE BAND OF SNOW DROPPING TO LESS THAN 1 MILE. IN FACT...SOME LAKE HURON CONTRIBUTION IS NOTED WITH A NARROW BAND OF SNOW COMING DOWN ACROSS SAGINAW BAY INTO MBS WITH 1/4 MILE VISIBILITY. LATEST RUC INCLUDING THE 12Z MODEL SUITE SUGGEST THE 1000-850MB WIND WILL BACK TOWARD THE NORTH THIS EVENING AS THIS DEFORMATION AXIS SWINGS SOUTH-SOUTHEAST ACROSS THE STATE. SPECIFIC HUMIDITIES ARE RUNNING AROUND 1 G/KG AND ACCUMULATIONS COULD ADD UP TO ANOTHER 1 INCH NORTH OF M59 THIS EVENING. FURTHER SOUTH...WITH THE BOUNDARY LAYER BECOMING MORE NORTHERLY...EXPECT SOME DOWNSLOPING INFLUENCES TO REDUCE THE SNOWFALL AMOUNTS AND DEFORMATION AXIS WEAKENING AS THE SURFACE TROUGH AND UPPER LEVEL TROUGH SWING SOUTHEAST OF THE STATE. THEN THE REAL COLD ADVECTION TAKES SHAPE TONIGHT WITH CONCERN SHIFTING TOWARD LAKE EFFECT SNOW FOR PORTIONS OF THE THUMB. BOTH THE NAM AND GFS ARE IN RATHER GOOD AGREEMENT WITH THE 1000-850MB FLOW WHICH IS RATHER PERSISTENT (360 DEGREES) FOR MOST OF THE NIGHT. TOWARD 09Z-12Z...FLOW BACKS A LITTLE MORE TAKING THE BAND OFFSHORE BUT STILL TOUCHING THE M10 CORRIDOR IN HURON COUNTY. INVERSION HEIGHTS CLIMB...PER BUFKIT PROFILES...FROM NEAR 850MB TO BETWEEN 800-750MB WITH LAKE INDUCED CAPES CLIMBING TOWARD 300 J/KG AND LAKE DELTA T/S INTO THE MIDDLE TEENS CELSIUS. 925MB CONVERGENCE AND OMEGA FIELDS LOOK RATHER IMPRESSIVE ACROSS HURON...SANILAC AND TOUCHING NORTHEAST ST CLAIR COUNTY OVERNIGHT SO ADDITIONAL SNOWFALL IS EXPECTED. LOCAL DECISION TREE SUGGESTS ANOTHER 2-4"/12HRS BUT WITH THE BAND MOVING OFFSHORE...WILL CUT THOSE VALUES TO ANOTHER 1-3" AND MENTION BRIEF PERIODS OF HEAVY SNOW IN THE FORECAST/GRIDS. WEATHER DOES QUIET DOWN ON TUESDAY WITH A COLD NORTHERLY FLOW AND MOISTURE DECREASING. THIS SHOULD ALLOW FOR SOME SUNNY BREAKS YET THAT COULD HELP STEEPEN THE LOW LEVEL LAPSE RATES...AND WOULD NOT BE SURPRISED TO SEE SOME LIGHT SNOW SHOWERS MOVING ACROSS THE CWA. WILL KEEP THE LOW POPS FOR MOST AREAS AWAY FROM LAKE HURON...AS LAKE BAND COULD STILL IMPACT THE M10 CORRIDOR IN HURON COUNTY. TEMPERATURES WILL BE QUITE CHILLY (OR SEASONABLE) TONIGHT AND TUESDAY WITH LOWS TONIGHT DROPPING BACK INTO THE TEENS. ON TUESDAY WITH 850MB TEMPS INTO THE NEGATIVE MID TEENS...WE WILL BE LUCKY TO TOUCH 30F. && .LONG TERM... MODIFYING TREND WEDNESDAY AND THURSDAY BEFORE ANOTHER SURGE OF ARCTIC AIR ARRIVES BY FRIDAY. MEDIUM RANGE MODELS (12Z EUROPEAN/CANADIAN GLOBAL/GFS) IN DECENT AGREEMENT THROUGH THE FIRST HALF OF THE WEEKEND. AMPLIFIED UPPER LEVEL RIDGE TO BUILD INTO THE CENTRAL GREAT LAKES ON WEDNESDAY. TUESDAY NIGHT IS SHAPING UP TO BE THE COLDEST NIGHT OF THE SEASON THUS FAR AS 1040+ MB HIGH SETS UP OVER THE NORTHERN OHIO VALLEY WEDNESDAY MORNING. HOWEVER...RELATIVELY WARM GROUND AND LACK OF SIGNIFICANT SNOW DEPTH OVER MUCH OF SOUTHEAST MICHIGAN SHOULD FACTOR IN. WENT FAIRLY CLOSE TO GFS MOS GUIDANCE...UPPER SINGLE NUMBERS TO LOWER TEENS. IF THIS WAS A MORE TYPICAL WINTER...WOULD HAVE EXPECTED MINS DOWN AROUND ZERO. TRAILING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA IS FORECASTED TO EJECT OFF TO THE NORTHEAST...AS MORE VIGOROUS UPPER WAVES OVER THE GULF OF ALASKA AND ALASKA EVENTUALLY CARVE OUT ANOTHER TROUGH OVER THE NORTH CENTRAL CONUS ON THURSDAY. SOME TIMING DIFFERENCES WITH THE SOUTHERN WAVE...ALONG WITH MEAGER MOISTURE INDICATED BY MODELS ON THURSDAY. NONE-THE-LESS...IT IS A DECENT WAVE AND POSSIBLE HELP FROM LAKE MICHIGAN...PREFER TO CARRY A LOW CHANCE OF LIGHT SNOW OR FLURRIES BY THURSDAY AFTERNOON. THERE IS SOME SEMBLANCE OF AN 850-700 MB THETA-E RIDGE/WEAK MOISTURE TRANSPORT MOVING THROUGH AS WELL. A LITTLE BETTER CHANCE OF SNOW SHOWERS THURSDAY NIGHT AND ESPECIALLY FRIDAY WITH COLD FRONT SLIDING THROUGH THURSDAY NIGHT AND LAKE EFFECT LIKELY KICKING IN BY FRIDAY AS 850 MB TEMPS DROP TO -16 TO -18 C. ARCTIC AIRMASS LOOKS TO BE SLOW TO PUSH EAST ON SATURDAY...WITH A CONTINUED CHANCE OF SNOW SHOWERS. && .PREV DISCUSSION...ISSUED 1228 PM EST MON JAN 15 2007 AVIATION... WITH THE STORM TRACKING WELL TO OUR EAST...DEFORMATION AXIS SNOW WILL IMPACT THE TRI CITIES REGION FOR THE REMAINDER OF THE AFTERNOON. WHILE THIS DEFORMATION AXIS WILL WEAKEN FURTHER...850-700MB TROUGH WILL SWING THROUGH TONIGHT AND MAY PROVIDE ADDITIONAL LIGHT SNOWFALL FOR THE ENTIRE REGION. THIS COULD BRING ABOUT BRIEF IFR CONDITIONS WITH MAINLY MVFR EXPECTED. SUBSIDENCE IN THE WAKE OF THIS TROUGH COMBINING WITH NORTHWEST FLOW AND FAVORABLE DOWNSLOPING WILL OVERTAKE THE REGION LATE TONIGHT INTO TUESDAY MORNING. NORTHWEST WINDS WILL REMAIN UP WITH GENERALLY 10-15KTS...AND GUSTS AS HIGH AS 20KTS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNT LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BGM LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1228 PM EST MON JAN 15 2007 .AVIATION... WITH THE STORM TRACKING WELL TO OUR EAST...DEFORMATION AXIS SNOW WILL IMPACT THE TRI CITIES REGION FOR THE REMAINDER OF THE AFTERNOON. WHILE THIS DEFORMATION AXIS WILL WEAKEN FURTHER...850-700MB TROUGH WILL SWING THROUGH TONIGHT AND MAY PROVIDE ADDITIONAL LIGHT SNOWFALL FOR THE ENTIRE REGION. THIS COULD BRING ABOUT BRIEF IFR CONDITIONS WITH MAINLY MVFR EXPECTED. SUBSIDENCE IN THE WAKE OF THIS TROUGH COMBINING WITH NORTHWEST FLOW AND FAVORABLE DOWNSLOPING WILL OVERTAKE THE REGION LATE TONIGHT INTO TUESDAY MORNING. NORTHWEST WINDS WILL REMAIN UP WITH GENERALLY 10-15KTS...AND GUSTS AS HIGH AS 20KTS. && .PREV DISCUSSION...ISSUED 801 AM EST MON JAN 15 2007 UPDATE... BASED ON RADAR RETURNS...WILL BE DROPPING ALL WINTER WEATHER HEADLINES WITHIN THE NEXT HALF HOUR. THE REMAINDER OF THE PRECIPITATION TODAY WILL REMAIN LIGHT. PREV DISCUSSION...ISSUED 629 AM EST MON JAN 15 2007 SHORT TERM...TODAY THE 09Z SURFACE ANALYSIS SHOWS A 1009MB LOW NEAR INDIANAPOLIS... WHICH IS ASSOCIATED WITH A MID LEVEL SHORT WAVE OVER THE MID MISSISSIPPI VALLEY. THIS WAVE IS EMBEDDED WITHIN THE SOUTHWEST FLOW IN ADVANCE OF THE LONG WAVE TROUGH OVER THE NORTHERN AND CENTRAL PLAINS. MID LEVEL FRONTAL FORCING WITHIN THE ENTRANCE REGION OF A 170KT UPPER LEVEL JET OVER SOUTHERN QUEBEC HAS PROVIDED WIDESPREAD PRECIPITATION ACROSS SOUTHERN MICHIGAN OVERNIGHT. LOW LEVEL SOUTHERLY FLOW HAS ADVECTED A SIGNIFICANT ENOUGH WEDGE OF WARM AIR ALOFT TO ALLOW MOST OF THE PRECIP ALONG AND SOUTH OF THE I 69 CORRIDOR TO FALL AS FREEZING RAIN...WITH SNOW AND SLEET MAINLY CONFINED TO THE SAGINAW VALLEY AND NORTHERN THUMB. SURFACE OBSERVATIONS ACROSS SE MI SHOW THE FREEZING LINE EXTENDING ALONG A DETROIT TO ADRIAN LINE. IT APPEARS FROM THE SURFACE OBSERVATIONS THAT THE WEAK LOW LEVEL COLD AIR ADVECTION HAS NOT BEEN ABLE TO OVERCOME THE LATENT HEAT RELEASE DUE TO FREEZING NEAR THE SURFACE. THUS TEMPS HAVE INCREASED A COUPLE DEGREES OVER THE LAST TWO HOURS. IN FACT...MOST OF WAYNE AND MONROE COUNTIES ARE NOW ABOVE FREEZING. THE LATEST AREA RADAR DATA SHOWS THE BACK EDGE OF THE PRECIP NOW MOVING INTO SW LOWER MI...SUPPORTING THE FASTER GFS AND RUC SOLUTIONS. BASED ON MODEL SOUNDINGS...PRECIP SHOULD TRANSITION TO FREEZING DRIZZLE BETWEEN 12Z AND 15Z AS MOISTURE ABOVE -10 C IS STRIPPED AWAY. THE NAM HOWEVER SHOWS SOME LINGERING FRONTOGENESIS IN THE 700-600MB LAYER ACROSS THE NORTHERN HALF OF THE FORECAST AREA THROUGH 15Z WHICH CAN NOT BE RULED OUT GIVEN THE STRENGTH OF THE UPPER JET. WITH THE EXCEPTION OF WAYNE AND MONROE COUNTIES...WILL KEEP THE WARNINGS GOING THROUGH THE REST OF THE MORNING. WARNINGS MAY BE ABLE TO BE DOWNGRADED TO FREEZING DRIZZLE ADVISORIES LATE THIS MORNING. HAVE RECEIVED SEVERAL REPORTS OF QUARTER TO HALF INCH ICE ACCUMULATIONS. WITH SURFACE TEMPS HOVERING IN THE LOWER 30S...THE MOST SIGNIFICANT ACCUMULATIONS HAVE BEEN ON ELEVATED SURFACES LIKE TREES AND POWER LINES. THE MAIN UPDATE TO THE HEADLINES THIS MORNING WAS TO ADJUST FOR MORE FREEZING RAIN FROM FNT TO PHN AS A LITTLE MORE WARM AIR ALOFT ADVECTED INTO THE FORECAST AREA THAN EARLIER MODELS SUGGESTED. THE ONLY OTHER MAJOR ADJUSTMENTS WAS TO DOWNGRADE MONROE AND WAYNE COUNTIES TO AN ADVISORY WITH CURRENT TEMPS NOW ABOVE FREEZING AT DTW/DET/TTF/DUH. CURRENT TRENDS ALSO SUPPORT A LITTLE LOWER SNOWFALL TOTALS ACROSS THE SAGINAW VALLEY AND THUMB REGION. LOW LEVEL COLD AIR ADVECTION AND DEEPER MOISTURE WILL WRAP BACK INTO THE AREA LATE THIS AFTERNOON...TRANSITIONING ANY LINGERING DRIZZLE TO LIGHT SNOW SHOWERS. WINDS WILL INCREASE TO THE 10 TO 20 MPH RANGE BY THIS AFTERNOON...MAINLY NORTH OF M 59...WHICH MAY CAUSE SOME ADDITIONAL PROBLEMS WITH TREES AND POWER LINES WEIGHTED DOWN WITH ICE. LONG TERM...MONDAY NIGHT THROUGH SUNDAY BY MONDAY NIGHT THE LOW PRESSURE SYSTEM THAT BROUGHT A WINTER STORM TO LOWER MICHIGAN WILL BE MOVING ACROSS THE NEW ENGLAND STATES...WITH A THERMAL TROUGH EXTENDING BACK ACROSS THE GREAT LAKES REGION. THE NAM SEEMS TO HAVE A BETTER HANDLE ON SHORTWAVE ENERGY DROPPING SOUTH OUT OF CANADA BASED ON WATER VAPOR IMAGERY AND REINFORCES THE UPPER LEVEL TROUGH OVER THE REGION. A NUMBER OF SHORTWAVES WILL MOVE OVER THE AREA MONDAY NIGHT AND TUESDAY. LIGHT SNOW WILL CONTINUE INTO THE EVENING ON MONDAY BEFORE SNOW SHOWERS BECOME PRIMARILY DRIVEN BY LAKE EFFECT AND DECREASE IN COVERAGE OVERNIGHT. THE NAM12 DOES INDICATE LOW LEVEL CONVERGENCE OVER THE THUMB...SHIFTING OFFSHORE BY LATE AT NIGHT. GIVEN THE SHIFTING TRAJECTORY FOR LAKE EFFECT SHOWERS ...WILL KEEP ACCUMULATIONS ON THE LOW SIDE IN THE 1-3 INCH RANGE. ON TUESDAY A WEAK 850MB TROUGH COMBINED WITH CONTINUED CYCLONIC FLOW AT THE SURFACE SHOULD YIELD NUMEROUS SNOW SHOWERS ACROSS THE AREA. THE SHOWERY NATURE OF THE SNOW WILL MAKE ACCUMULATIONS VARY WIDELY...BUT WILL EXPECT ACCUMULATIONS TO GENERALLY REMAIN AROUND AN INCH OR LESS. INSTABILITY WILL PEAK TUESDAY EVENING AS THE UPPER LEVEL COLD POOL MOVES SOUTH OVER THE AREA. MODEL SOUNDINGS OVER SOUTHERN LAKE HURON INDICATE 850 J/KG OF LAKE INDUCED CAPE AND EQUILIBRIUM LEVELS OVER 14000 FEET. WILL EXPECT ANOTHER ROUND OF SNOW SHOWERS AS THE 700MB TROUGH AXIS PASSES AND WILL CONTINUE TO CARRY SOME ADDITIONAL LIGHT ACCUMULATIONS OVER THE THUMB INTO THE OVERNIGHT HOURS. SKIES WILL START TO SCATTER OUT LATE TUESDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE SOUTHWEST. WILL GO SEVERAL DEGREES BELOW GUIDANCE OVER OUR SOUTHWESTERN COUNTIES THAT ARE CLOSER TO THE SURFACE HIGH. THE UPPER LEVEL RIDGE BUILDS OVER THE AREA ON WEDNESDAY WITH WARM AIR ADVECTION BEGINNING AS SOUTHWESTERLY FLOW INCREASES ON THE WEST SIDE OF THE SURFACE HIGH. MODELS ADVERTISE THE NEXT UPPER LEVEL TROUGH TO QUICKLY APPROACH BY THE END OF THE WEEK WITH A NUMBER OF WAVES MOVING OVER THE REGION IN THE THURSDAY NIGHT/FRIDAY TIME FRAME. THIS WILL BRING THE NEXT CHANCE OF LIGHT SNOW AND ANOTHER COLD FRONT TO REINFORCE THE COLD AIR OVER THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 5 PM MONDAY. && $$ SHORT TERM...CONSIDINE LONG TERM....KAHL AVIATION...BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1130 AM EST MON JAN 15 2007 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR SNOW THROUGH THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A LONGWAVE TROUGH EXTENDING FROM NORTHERN JAMES BAY SOUTHWEST INTO THE CENTRAL PLAINS THEN TO NORTHERN BAJA. A RIDGE STRETCHES ACROSS THE PACIFIC NORTHWEST INTO THE ALBERTA. A SHORTWAVE TROUGH EJECTED OUT OF THE TROUGH IS OVER WESTERN U.P. AND WESTERN LAKE SUPERIOR. OTHERS UPSTREAM SHORTWAVES ARE OVER KANSAS...ARIZONA AND WESTERN NORTH DAKOTA. SURFACE ANALYSIS DEPICT A LOW OVER THE LOWER GREAT LAKES...A WEAK TROUGH EXTENDING WEST TO NORTHERN IOWA...AND A RIDGE BLANKETING MUCH OF NORTHERN PLAINS AND MANITOBA. AN 850MB THERMAL TROUGH (-20C) RUNS FROM EASTERN NORTH DAKOTA INTO WESTERN MANITOBA CAUSES TEMPERATURES OVER WESTERN LAKE SUPERIOR TO BE AROUND -17C AND -15C OVER THE PART OF THE LAKE. BOTH COOL ENOUGH TO PRODUCE LOW LEVEL INSTABILITY FOR LAKE EFFECT SNOWS ENHANCEMENT. LOW LEVEL CONVERGENCE CONTINUE TO PRODUCE HEAVY SNOW FALL OVER NORTHERN U.P. LOWEST INVERSION IS AROUND 3.5K FEET. DEEP (SURFACE-850MB) MOISTURE IS 80 TO 85 PERCENT. PW IS IN THE .25 TO .3 INCH RANGE WHICH IS FAIRLY DRY. THE HEAVIEST SNOW ARE OCCURRING WHERE THE STRONGEST LAKE EFFECT SNOWS ARE OCCURRING OVER NORTH CENTRAL U.P. AND EXTREME WESTERN SHORE OF THE FORECAST AREA. THE LONGWAVE TROUGH WILL EDGE A LITTLE EAST BECOMING MORE CENTERED OVER THE FORECAST AREA THIS AFTERNOON. THE LOWER GREAT LAKES LOW WILL SHIFT TO NEW ENGLAND AS THE NORTHERN PLAINS RIDGE EDGES ONLY A FEW MILES EAST. SURFACE WINDS WILL BACK A LITTLE MORE TO THE NORTH. SYSTEM SNOW CONTINUE OVER THE FORECAST AREA MAINLY ALONG THE LAKE MICHIGAN SHORE. KMQT-88D INDICATES LES BANDS DEVELOPING OVER MARQUETTE COUNTY AND WESTERN ALGER. SURFACE REPORTS ALSO INDICATE HEAVY LES OVER EXTREMELY WESTERN U.P. RUC CONTINUES TO SHOW CONVERGENCE OVER CENTRAL LAKE SUPERIOR. 280K ISENTROPIC ANALYSIS INDICATES MOSTLY DESCENT ACROSS THE AREA. MIXING RATIO ABOUT 1 G/KG ACROSS THE SOUTHEAST PART OF THE FORECAST AREA. QUESTION WHETHER TO EXTEND THE WARNING TO WESTERN ALGER COUNTY. AS THE WINDS BACK THIS AFTERNOON THE BANDS WILL SHIFT THROUGH THE DAY AND DRY AIR WILL ADVANCE INTO THE AREA FROM THE WEST WHICH SHOULD WEAKEN THE LES ACROSS THE AREA. UP TO 7 INCHES OVER WILL FALL OVER WESTERN ALGER COUNTY. SO WILL LEAVE IT WITH AN ADVISORY. THIS EVENING THE SHORTWAVE WILL MOVE EAST. DRY AIR WILL MOVE INTO THE AREA. SURFACE TEMPERATURE WILL REMAIN COOL ENOUGH TO KEEP LAKE EFFECT SNOWS GOING. HOWEVER...THE DRYNESS WILL LIMIT SNOWFALL. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 11 PM EST MONDAY FOR MIZ001>004-006-084-085. LAKE EFFECT SNOW WARNING FROM 11 PM EST /10 PM CST/ THIS EVENING TO 11 PM EST /10 PM CST/ MONDAY FOR MIZ005-009. SNOW ADVISORY FROM 1 AM TO 11 PM EST MONDAY FOR MIZ013. SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR MIZ010>012. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 801 AM EST MON JAN 15 2007 .UPDATE... BASED ON RADAR RETURNS...WILL BE DROPPING ALL WINTER WEATHER HEADLINES WITHIN THE NEXT HALF HOUR. THE REMAINDER OF THE PRECIPITATION TODAY WILL REMAIN LIGHT. && .PREV DISCUSSION...ISSUED 629 AM EST MON JAN 15 2007 AVIATION... THE BACK EDGE OF THE WIDESPREAD PRECIPITATION IS MOVING INTO SE MI AS OF 11Z. BASED ON EXTRAPOLATION FROM RADAR...THE WIDESPREAD PRECIP WILL EXIT TO THE EAST OF THE TAF SITES SHORTLY AFTER 12Z. BASED ON MODEL SOUNDINGS...WOULD EXPECT SOME DRIZZLE/FREEZING DRIZZLE IN THE WAKE OF THE WIDESPREAD PRECIPITATION. MBS WILL BE INTO THE COLDER AIR AND MAY BE ABLE TO REMAIN LIGHT SNOW/FLURRIES INTO THE AFTERNOON. DTW/DET HAVE BEEN HOVERING AROUND 33/34 DEGREES FOR SEVERAL HOURS. THE TEMPERATURES AROUND DETROIT WILL FALL TO THE FREEZING MARK OR SLIGHTLY LOWER BY 15Z AS THE COLDER AIR STARTS FILTERING INTO SE MICHIGAN IN THE WAKE OF THE DEPARTING SURFACE LOW OVER OHIO. SO THERE IS STILL A CHANCE FOR SOME FREEZING DRIZZLE AT DETROIT LATER THIS MORNING. WIDESPREAD IFR CEILINGS ARE EXPECTED TO PERSIST THROUGH THE MORNING AND INTO THE AFTERNOON. COLDER AND DRIER AIR WILL ADVANCE INTO THE REGION DURING THE AFTERNOON. CEILINGS WILL GRADUALLY RESPOND BY LIFTING TO THE VFR CATEGORY BY 20Z. && .PREV DISCUSSION...ISSUED 442 AM EST MON JAN 15 2007 SHORT TERM...TODAY THE 09Z SURFACE ANALYSIS SHOWS A 1009MB LOW NEAR INDIANAPOLIS... WHICH IS ASSOCIATED WITH A MID LEVEL SHORT WAVE OVER THE MID MISSISSIPPI VALLEY. THIS WAVE IS EMBEDDED WITHIN THE SOUTHWEST FLOW IN ADVANCE OF THE LONG WAVE TROUGH OVER THE NORTHERN AND CENTRAL PLAINS. MID LEVEL FRONTAL FORCING WITHIN THE ENTRANCE REGION OF A 170KT UPPER LEVEL JET OVER SOUTHERN QUEBEC HAS PROVIDED WIDESPREAD PRECIPITATION ACROSS SOUTHERN MICHIGAN OVERNIGHT. LOW LEVEL SOUTHERLY FLOW HAS ADVECTED A SIGNIFICANT ENOUGH WEDGE OF WARM AIR ALOFT TO ALLOW MOST OF THE PRECIP ALONG AND SOUTH OF THE I 69 CORRIDOR TO FALL AS FREEZING RAIN...WITH SNOW AND SLEET MAINLY CONFINED TO THE SAGINAW VALLEY AND NORTHERN THUMB. SURFACE OBSERVATIONS ACROSS SE MI SHOW THE FREEZING LINE EXTENDING ALONG A DETROIT TO ADRIAN LINE. IT APPEARS FROM THE SURFACE OBSERVATIONS THAT THE WEAK LOW LEVEL COLD AIR ADVECTION HAS NOT BEEN ABLE TO OVERCOME THE LATENT HEAT RELEASE DUE TO FREEZING NEAR THE SURFACE. THUS TEMPS HAVE INCREASED A COUPLE DEGREES OVER THE LAST TWO HOURS. IN FACT...MOST OF WAYNE AND MONROE COUNTIES ARE NOW ABOVE FREEZING. THE LATEST AREA RADAR DATA SHOWS THE BACK EDGE OF THE PRECIP NOW MOVING INTO SW LOWER MI...SUPPORTING THE FASTER GFS AND RUC SOLUTIONS. BASED ON MODEL SOUNDINGS...PRECIP SHOULD TRANSITION TO FREEZING DRIZZLE BETWEEN 12Z AND 15Z AS MOISTURE ABOVE -10 C IS STRIPPED AWAY. THE NAM HOWEVER SHOWS SOME LINGERING FRONTOGENESIS IN THE 700-600MB LAYER ACROSS THE NORTHERN HALF OF THE FORECAST AREA THROUGH 15Z WHICH CAN NOT BE RULED OUT GIVEN THE STRENGTH OF THE UPPER JET. WITH THE EXCEPTION OF WAYNE AND MONROE COUNTIES...WILL KEEP THE WARNINGS GOING THROUGH THE REST OF THE MORNING. WARNINGS MAY BE ABLE TO BE DOWNGRADED TO FREEZING DRIZZLE ADVISORIES LATE THIS MORNING. HAVE RECEIVED SEVERAL REPORTS OF QUARTER TO HALF INCH ICE ACCUMULATIONS. WITH SURFACE TEMPS HOVERING IN THE LOWER 30S...THE MOST SIGNIFICANT ACCUMULATIONS HAVE BEEN ON ELEVATED SURFACES LIKE TREES AND POWER LINES. THE MAIN UPDATE TO THE HEADLINES THIS MORNING WAS TO ADJUST FOR MORE FREEZING RAIN FROM FNT TO PHN AS A LITTLE MORE WARM AIR ALOFT ADVECTED INTO THE FORECAST AREA THAN EARLIER MODELS SUGGESTED. THE ONLY OTHER MAJOR ADJUSTMENTS WAS TO DOWNGRADE MONROE AND WAYNE COUNTIES TO AN ADVISORY WITH CURRENT TEMPS NOW ABOVE FREEZING AT DTW/DET/TTF/DUH. CURRENT TRENDS ALSO SUPPORT A LITTLE LOWER SNOWFALL TOTALS ACROSS THE SAGINAW VALLEY AND THUMB REGION. LOW LEVEL COLD AIR ADVECTION AND DEEPER MOISTURE WILL WRAP BACK INTO THE AREA LATE THIS AFTERNOON...TRANSITIONING ANY LINGERING DRIZZLE TO LIGHT SNOW SHOWERS. WINDS WILL INCREASE TO THE 10 TO 20 MPH RANGE BY THIS AFTERNOON...MAINLY NORTH OF M 59...WHICH MAY CAUSE SOME ADDITIONAL PROBLEMS WITH TREES AND POWER LINES WEIGHTED DOWN WITH ICE. LONG TERM...MONDAY NIGHT THROUGH SUNDAY BY MONDAY NIGHT THE LOW PRESSURE SYSTEM THAT BROUGHT A WINTER STORM TO LOWER MICHIGAN WILL BE MOVING ACROSS THE NEW ENGLAND STATES...WITH A THERMAL TROUGH EXTENDING BACK ACROSS THE GREAT LAKES REGION. THE NAM SEEMS TO HAVE A BETTER HANDLE ON SHORTWAVE ENERGY DROPPING SOUTH OUT OF CANADA BASED ON WATER VAPOR IMAGERY AND REINFORCES THE UPPER LEVEL TROUGH OVER THE REGION. A NUMBER OF SHORTWAVES WILL MOVE OVER THE AREA MONDAY NIGHT AND TUESDAY. LIGHT SNOW WILL CONTINUE INTO THE EVENING ON MONDAY BEFORE SNOW SHOWERS BECOME PRIMARILY DRIVEN BY LAKE EFFECT AND DECREASE IN COVERAGE OVERNIGHT. THE NAM12 DOES INDICATE LOW LEVEL CONVERGENCE OVER THE THUMB...SHIFTING OFFSHORE BY LATE AT NIGHT. GIVEN THE SHIFTING TRAJECTORY FOR LAKE EFFECT SHOWERS ...WILL KEEP ACCUMULATIONS ON THE LOW SIDE IN THE 1-3 INCH RANGE. ON TUESDAY A WEAK 850MB TROUGH COMBINED WITH CONTINUED CYCLONIC FLOW AT THE SURFACE SHOULD YIELD NUMEROUS SNOW SHOWERS ACROSS THE AREA. THE SHOWERY NATURE OF THE SNOW WILL MAKE ACCUMULATIONS VARY WIDELY...BUT WILL EXPECT ACCUMULATIONS TO GENERALLY REMAIN AROUND AN INCH OR LESS. INSTABILITY WILL PEAK TUESDAY EVENING AS THE UPPER LEVEL COLD POOL MOVES SOUTH OVER THE AREA. MODEL SOUNDINGS OVER SOUTHERN LAKE HURON INDICATE 850 J/KG OF LAKE INDUCED CAPE AND EQUILIBRIUM LEVELS OVER 14000 FEET. WILL EXPECT ANOTHER ROUND OF SNOW SHOWERS AS THE 700MB TROUGH AXIS PASSES AND WILL CONTINUE TO CARRY SOME ADDITIONAL LIGHT ACCUMULATIONS OVER THE THUMB INTO THE OVERNIGHT HOURS. SKIES WILL START TO SCATTER OUT LATE TUESDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE SOUTHWEST. WILL GO SEVERAL DEGREES BELOW GUIDANCE OVER OUR SOUTHWESTERN COUNTIES THAT ARE CLOSER TO THE SURFACE HIGH. THE UPPER LEVEL RIDGE BUILDS OVER THE AREA ON WEDNESDAY WITH WARM AIR ADVECTION BEGINNING AS SOUTHWESTERLY FLOW INCREASES ON THE WEST SIDE OF THE SURFACE HIGH. MODELS ADVERTISE THE NEXT UPPER LEVEL TROUGH TO QUICKLY APPROACH BY THE END OF THE WEEK WITH A NUMBER OF WAVES MOVING OVER THE REGION IN THE THURSDAY NIGHT/FRIDAY TIME FRAME. THIS WILL BRING THE NEXT CHANCE OF LIGHT SNOW AND ANOTHER COLD FRONT TO REINFORCE THE COLD AIR OVER THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 AM WEDNESDAY. LAKE ST CLAIR...ICE STORM WARNING...LCZ422-LCZ460 UNTIL NOON MONDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 5 PM MONDAY. && $$ AVIATION...CONSIDINE SHORT TERM...CONSIDINE LONG TERM....KAHL YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 629 AM EST MON JAN 15 2007 .AVIATION... THE BACK EDGE OF THE WIDESPREAD PRECIPITATION IS MOVING INTO SE MI AS OF 11Z. BASED ON EXTRAPOLATION FROM RADAR...THE WIDESPREAD PRECIP WILL EXIT TO THE EAST OF THE TAF SITES SHORTLY AFTER 12Z. BASED ON MODEL SOUNDINGS...WOULD EXPECT SOME DRIZZLE/FREEZING DRIZZLE IN THE WAKE OF THE WIDESPREAD PRECIPITATION. MBS WILL BE INTO THE COLDER AIR AND MAY BE ABLE TO REMAIN LIGHT SNOW/FLURRIES INTO THE AFTERNOON. DTW/DET HAVE BEEN HOVERING AROUND 33/34 DEGREES FOR SEVERAL HOURS. THE TEMPERATURES AROUND DETROIT WILL FALL TO THE FREEZING MARK OR SLIGHTLY LOWER BY 15Z AS THE COLDER AIR STARTS FILTERING INTO SE MICHIGAN IN THE WAKE OF THE DEPARTING SURFACE LOW OVER OHIO. SO THERE IS STILL A CHANCE FOR SOME FREEZING DRIZZLE AT DETROIT LATER THIS MORNING. WIDESPREAD IFR CEILINGS ARE EXPECTED TO PERSIST THROUGH THE MORNING AND INTO THE AFTERNOON. COLDER AND DRIER AIR WILL ADVANCE INTO THE REGION DURING THE AFTERNOON. CEILINGS WILL GRADUALLY RESPOND BY LIFTING TO THE VFR CATEGORY BY 20Z. && .PREV DISCUSSION...ISSUED 442 AM EST MON JAN 15 2007 SHORT TERM...TODAY THE 09Z SURFACE ANALYSIS SHOWS A 1009MB LOW NEAR INDIANAPOLIS... WHICH IS ASSOCIATED WITH A MID LEVEL SHORT WAVE OVER THE MID MISSISSIPPI VALLEY. THIS WAVE IS EMBEDDED WITHIN THE SOUTHWEST FLOW IN ADVANCE OF THE LONG WAVE TROUGH OVER THE NORTHERN AND CENTRAL PLAINS. MID LEVEL FRONTAL FORCING WITHIN THE ENTRANCE REGION OF A 170KT UPPER LEVEL JET OVER SOUTHERN QUEBEC HAS PROVIDED WIDESPREAD PRECIPITATION ACROSS SOUTHERN MICHIGAN OVERNIGHT. LOW LEVEL SOUTHERLY FLOW HAS ADVECTED A SIGNIFICANT ENOUGH WEDGE OF WARM AIR ALOFT TO ALLOW MOST OF THE PRECIP ALONG AND SOUTH OF THE I 69 CORRIDOR TO FALL AS FREEZING RAIN...WITH SNOW AND SLEET MAINLY CONFINED TO THE SAGINAW VALLEY AND NORTHERN THUMB. SURFACE OBSERVATIONS ACROSS SE MI SHOW THE FREEZING LINE EXTENDING ALONG A DETROIT TO ADRIAN LINE. IT APPEARS FROM THE SURFACE OBSERVATIONS THAT THE WEAK LOW LEVEL COLD AIR ADVECTION HAS NOT BEEN ABLE TO OVERCOME THE LATENT HEAT RELEASE DUE TO FREEZING NEAR THE SURFACE. THUS TEMPS HAVE INCREASED A COUPLE DEGREES OVER THE LAST TWO HOURS. IN FACT...MOST OF WAYNE AND MONROE COUNTIES ARE NOW ABOVE FREEZING. THE LATEST AREA RADAR DATA SHOWS THE BACK EDGE OF THE PRECIP NOW MOVING INTO SW LOWER MI...SUPPORTING THE FASTER GFS AND RUC SOLUTIONS. BASED ON MODEL SOUNDINGS...PRECIP SHOULD TRANSITION TO FREEZING DRIZZLE BETWEEN 12Z AND 15Z AS MOISTURE ABOVE -10 C IS STRIPPED AWAY. THE NAM HOWEVER SHOWS SOME LINGERING FRONTOGENESIS IN THE 700-600MB LAYER ACROSS THE NORTHERN HALF OF THE FORECAST AREA THROUGH 15Z WHICH CAN NOT BE RULED OUT GIVEN THE STRENGTH OF THE UPPER JET. WITH THE EXCEPTION OF WAYNE AND MONROE COUNTIES...WILL KEEP THE WARNINGS GOING THROUGH THE REST OF THE MORNING. WARNINGS MAY BE ABLE TO BE DOWNGRADED TO FREEZING DRIZZLE ADVISORIES LATE THIS MORNING. HAVE RECEIVED SEVERAL REPORTS OF QUARTER TO HALF INCH ICE ACCUMULATIONS. WITH SURFACE TEMPS HOVERING IN THE LOWER 30S...THE MOST SIGNIFICANT ACCUMULATIONS HAVE BEEN ON ELEVATED SURFACES LIKE TREES AND POWER LINES. THE MAIN UPDATE TO THE HEADLINES THIS MORNING WAS TO ADJUST FOR MORE FREEZING RAIN FROM FNT TO PHN AS A LITTLE MORE WARM AIR ALOFT ADVECTED INTO THE FORECAST AREA THAN EARLIER MODELS SUGGESTED. THE ONLY OTHER MAJOR ADJUSTMENTS WAS TO DOWNGRADE MONROE AND WAYNE COUNTIES TO AN ADVISORY WITH CURRENT TEMPS NOW ABOVE FREEZING AT DTW/DET/TTF/DUH. CURRENT TRENDS ALSO SUPPORT A LITTLE LOWER SNOWFALL TOTALS ACROSS THE SAGINAW VALLEY AND THUMB REGION. LOW LEVEL COLD AIR ADVECTION AND DEEPER MOISTURE WILL WRAP BACK INTO THE AREA LATE THIS AFTERNOON...TRANSITIONING ANY LINGERING DRIZZLE TO LIGHT SNOW SHOWERS. WINDS WILL INCREASE TO THE 10 TO 20 MPH RANGE BY THIS AFTERNOON...MAINLY NORTH OF M 59...WHICH MAY CAUSE SOME ADDITIONAL PROBLEMS WITH TREES AND POWER LINES WEIGHTED DOWN WITH ICE. LONG TERM...MONDAY NIGHT THROUGH SUNDAY BY MONDAY NIGHT THE LOW PRESSURE SYSTEM THAT BROUGHT A WINTER STORM TO LOWER MICHIGAN WILL BE MOVING ACROSS THE NEW ENGLAND STATES...WITH A THERMAL TROUGH EXTENDING BACK ACROSS THE GREAT LAKES REGION. THE NAM SEEMS TO HAVE A BETTER HANDLE ON SHORTWAVE ENERGY DROPPING SOUTH OUT OF CANADA BASED ON WATER VAPOR IMAGERY AND REINFORCES THE UPPER LEVEL TROUGH OVER THE REGION. A NUMBER OF SHORTWAVES WILL MOVE OVER THE AREA MONDAY NIGHT AND TUESDAY. LIGHT SNOW WILL CONTINUE INTO THE EVENING ON MONDAY BEFORE SNOW SHOWERS BECOME PRIMARILY DRIVEN BY LAKE EFFECT AND DECREASE IN COVERAGE OVERNIGHT. THE NAM12 DOES INDICATE LOW LEVEL CONVERGENCE OVER THE THUMB...SHIFTING OFFSHORE BY LATE AT NIGHT. GIVEN THE SHIFTING TRAJECTORY FOR LAKE EFFECT SHOWERS ...WILL KEEP ACCUMULATIONS ON THE LOW SIDE IN THE 1-3 INCH RANGE. ON TUESDAY A WEAK 850MB TROUGH COMBINED WITH CONTINUED CYCLONIC FLOW AT THE SURFACE SHOULD YIELD NUMEROUS SNOW SHOWERS ACROSS THE AREA. THE SHOWERY NATURE OF THE SNOW WILL MAKE ACCUMULATIONS VARY WIDELY...BUT WILL EXPECT ACCUMULATIONS TO GENERALLY REMAIN AROUND AN INCH OR LESS. INSTABILITY WILL PEAK TUESDAY EVENING AS THE UPPER LEVEL COLD POOL MOVES SOUTH OVER THE AREA. MODEL SOUNDINGS OVER SOUTHERN LAKE HURON INDICATE 850 J/KG OF LAKE INDUCED CAPE AND EQUILIBRIUM LEVELS OVER 14000 FEET. WILL EXPECT ANOTHER ROUND OF SNOW SHOWERS AS THE 700MB TROUGH AXIS PASSES AND WILL CONTINUE TO CARRY SOME ADDITIONAL LIGHT ACCUMULATIONS OVER THE THUMB INTO THE OVERNIGHT HOURS. SKIES WILL START TO SCATTER OUT LATE TUESDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE SOUTHWEST. WILL GO SEVERAL DEGREES BELOW GUIDANCE OVER OUR SOUTHWESTERN COUNTIES THAT ARE CLOSER TO THE SURFACE HIGH. THE UPPER LEVEL RIDGE BUILDS OVER THE AREA ON WEDNESDAY WITH WARM AIR ADVECTION BEGINNING AS SOUTHWESTERLY FLOW INCREASES ON THE WEST SIDE OF THE SURFACE HIGH. MODELS ADVERTISE THE NEXT UPPER LEVEL TROUGH TO QUICKLY APPROACH BY THE END OF THE WEEK WITH A NUMBER OF WAVES MOVING OVER THE REGION IN THE THURSDAY NIGHT/FRIDAY TIME FRAME. THIS WILL BRING THE NEXT CHANCE OF LIGHT SNOW AND ANOTHER COLD FRONT TO REINFORCE THE COLD AIR OVER THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070- MIZ075-MIZ082 UNTIL NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054 UNTIL NOON MONDAY. WINTER STORM WARNING...MIZ055-MIZ060 UNTIL NOON MONDAY. FREEZING RAIN ADVISORY...MIZ076-MIZ083 UNTIL NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNT LAKE ST CLAIR...ICE STORM WARNING...LCZ422-LCZ460 UNTIL NOON MONDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 5 PM MONDAY. && $$ AVIATION...CONSIDINE SHORT TERM...CONSIDINE LONG TERM....KAHL YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 442 AM EST MON JAN 15 2007 .SHORT TERM...TODAY THE 09Z SURFACE ANALYSIS SHOWS A 1009MB LOW NEAR INDIANAPOLIS... WHICH IS ASSOCIATED WITH A MID LEVEL SHORT WAVE OVER THE MID MISSISSIPPI VALLEY. THIS WAVE IS EMBEDDED WITHIN THE SOUTHWEST FLOW IN ADVANCE OF THE LONG WAVE TROUGH OVER THE NORTHERN AND CENTRAL PLAINS. MID LEVEL FRONTAL FORCING WITHIN THE ENTRANCE REGION OF A 170KT UPPER LEVEL JET OVER SOUTHERN QUEBEC HAS PROVIDED WIDESPREAD PRECIPITATION ACROSS SOUTHERN MICHIGAN OVERNIGHT. LOW LEVEL SOUTHERLY FLOW HAS ADVECTED A SIGNIFICANT ENOUGH WEDGE OF WARM AIR ALOFT TO ALLOW MOST OF THE PRECIP ALONG AND SOUTH OF THE I 69 CORRIDOR TO FALL AS FREEZING RAIN...WITH SNOW AND SLEET MAINLY CONFINED TO THE SAGINAW VALLEY AND NORTHERN THUMB. SURFACE OBSERVATIONS ACROSS SE MI SHOW THE FREEZING LINE EXTENDING ALONG AND NORTH OF A DETROIT TO ADRIAN LINE. IT APPEARS FROM THE SURFACE OBSERVATIONS THAT THE LACK OF LOW LEVEL COLD AIR ADVECTION HAS NOT BEEN ABLE TO OVERCOME THE LATENT HEAT RELEASE DUE TO FREEZING NEAR THE SURFACE. THUS TEMPS HAVE INCREASED A COUPLE DEGREES OVER THE LAST TWO HOURS. IN FACT...MOST OF WAYNE AND MONROE COUNTIES ARE NOW ABOVE FREEZING. THE LATEST AREA RADAR DATA SHOWS THE BACK EDGE OF THE PRECIP NOW MOVING INTO SW LOWER MI...SUPPORTING THE FASTER GFS AND RUC SOLUTIONS. BASED ON MODEL SOUNDINGS...PRECIP SHOULD TRANSITION TO FREEZING DRIZZLE BETWEEN 12Z AND 15Z AS MOISTURE ABOVE -10 C IS STRIPPED AWAY. THE NAM HOWEVER SHOWS SOME LINGERING FRONTOGENESIS IN THE 700-600MB LAYER ACROSS THE NORTHERN HALF OF THE FORECAST AREA THROUGH 15Z WHICH CAN NOT BE RULED OUT GIVEN THE STRENGTH OF THE UPPER JET. WITH THE EXCEPTION OF WAYNE AND MONROE COUNTIES...WILL KEEP THE WARNINGS GOING THROUGH THE REST OF THE MORNING. WARNINGS MAY BE ABLE TO BE DOWNGRADED TO FREEZING DRIZZLE ADVISORIES LATE THIS MORNING. HAVE RECEIVED SEVERAL REPORTS OF QUARTER TO HALF INCH ICE ACCUMULATIONS. WITH SURFACE TEMPS HOVERING IN THE LOWER 30S...THE MOST SIGNIFICANT ACCUMULATIONS HAVE BEEN ON ELEVATED SURFACES LIKE TREES AND POWER LINES. THE MAIN UPDATE TO THE HEADLINES THIS MORNING WAS TO ADJUST FOR MORE FREEZING RAIN FROM FNT TO PHN AS A LITTLE MORE WARM AIR ALOFT ADVECTED INTO THE FORECAST AREA THAN EARLIER MODELS SUGGESTED. THE ONLY OTHER MAJOR ADJUSTMENTS WAS TO DOWNGRADE MONROE AND WAYNE COUNTIES TO AN ADVISORY WITH CURRENT TEMPS NOW ABOVE FREEZING AT DTW/DET/TTF/DUH. CURRENT TRENDS ALSO SUPPORT A LITTLE LOWER SNOWFALL TOTALS ACROSS THE SAGINAW VALLEY AND THUMB REGION. LOW LEVEL COLD AIR ADVECTION AND DEEPER MOISTURE WILL WRAP BACK INTO THE AREA LATE THIS AFTERNOON...TRANSITIONING ANY LINGERING DRIZZLE TO LIGHT SNOW SHOWERS. WINDS WILL INCREASE TO THE 10 TO 20 MPH RANGE BY THIS AFTERNOON...MAINLY NORTH OF M 59...WHICH MAY CAUSE SOME ADDITIONAL PROBLEMS WITH TREES AND POWER LINES WEIGHTED DOWN WITH ICE. && .LONG TERM...MONDAY NIGHT THROUGH SUNDAY BY MONDAY NIGHT THE LOW PRESSURE SYSTEM THAT BROUGHT A WINTER STORM TO LOWER MICHIGAN WILL BE MOVING ACROSS THE NEW ENGLAND STATES...WITH A THERMAL TROUGH EXTENDING BACK ACROSS THE GREAT LAKES REGION. THE NAM SEEMS TO HAVE A BETTER HANDLE ON SHORTWAVE ENERGY DROPPING SOUTH OUT OF CANADA BASED ON WATER VAPOR IMAGERY AND REINFORCES THE UPPER LEVEL TROUGH OVER THE REGION. A NUMBER OF SHORTWAVES WILL MOVE OVER THE AREA MONDAY NIGHT AND TUESDAY. LIGHT SNOW WILL CONTINUE INTO THE EVENING ON MONDAY BEFORE SNOW SHOWERS BECOME PRIMARILY DRIVEN BY LAKE EFFECT AND DECREASE IN COVERAGE OVERNIGHT. THE NAM12 DOES INDICATE LOW LEVEL CONVERGENCE OVER THE THUMB...SHIFTING OFFSHORE BY LATE AT NIGHT. GIVEN THE SHIFTING TRAJECTORY FOR LAKE EFFECT SHOWERS ...WILL KEEP ACCUMULATIONS ON THE LOW SIDE IN THE 1-3 INCH RANGE. ON TUESDAY A WEAK 850MB TROUGH COMBINED WITH CONTINUED CYCLONIC FLOW AT THE SURFACE SHOULD YIELD NUMEROUS SNOW SHOWERS ACROSS THE AREA. THE SHOWERY NATURE OF THE SNOW WILL MAKE ACCUMULATIONS VARY WIDELY...BUT WILL EXPECT ACCUMULATIONS TO GENERALLY REMAIN AROUND AN INCH OR LESS. INSTABILITY WILL PEAK TUESDAY EVENING AS THE UPPER LEVEL COLD POOL MOVES SOUTH OVER THE AREA. MODEL SOUNDINGS OVER SOUTHERN LAKE HURON INDICATE 850 J/KG OF LAKE INDUCED CAPE AND EQUILIBRIUM LEVELS OVER 14000 FEET. WILL EXPECT ANOTHER ROUND OF SNOW SHOWERS AS THE 700MB TROUGH AXIS PASSES AND WILL CONTINUE TO CARRY SOME ADDITIONAL LIGHT ACCUMULATIONS OVER THE THUMB INTO THE OVERNIGHT HOURS. SKIES WILL START TO SCATTER OUT LATE TUESDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE SOUTHWEST. WILL GO SEVERAL DEGREES BELOW GUIDANCE OVER OUR SOUTHWESTERN COUNTIES THAT ARE CLOSER TO THE SURFACE HIGH. THE UPPER LEVEL RIDGE BUILDS OVER THE AREA ON WEDNESDAY WITH WARM AIR ADVECTION BEGINNING AS SOUTHWESTERLY FLOW INCREASES ON THE WEST SIDE OF THE SURFACE HIGH. MODELS ADVERTISE THE NEXT UPPER LEVEL TROUGH TO QUICKLY APPROACH BY THE END OF THE WEEK WITH A NUMBER OF WAVES MOVING OVER THE REGION IN THE THURSDAY NIGHT/FRIDAY TIME FRAME. THIS WILL BRING THE NEXT CHANCE OF LIGHT SNOW AND ANOTHER COLD FRONT TO REINFORCE THE COLD AIR OVER THE REGION. && .PREV DISCUSSION...ISSUED 1255 AM EST MON JAN 15 2007 AVIATION... PRECIPITATION HAD SPREAD OVER MOST OF SE MICHIGAN AT PRESS TIME, AND ALL TERMINAL SITES. OBSERVATIONS, ESPECIALLY RADAR DATA, SHOW THE AMOUNT AND DURATION WILL HAVE CONSIDERABLY GREATER IMPACTS ON AVIATION THAN WHAT OCCURRED ON SUNDAY. THE DOMINANT PRECIPITATION TYPE WILL BE FREEZING RAIN AT DTW/DET, SLEET AND SNOW AT FNT, AND SNOW AT MBS. THE 06Z-14Z WINDOW STILL LOOKS GOOD FOR THE HEAVIEST PRECIPITATION AT ALL TERMINALS, PUNCTUATED BY IFR CEILING AND VISIBILITY. SOME LIGHT FREEZING DRIZZLE WILL OCCUR DURING THE LATE MORNING AND EARLY AFTERNOON AS DRY AIR MOVES IN THROUGH THE MID LEVELS AND AS THE SYSTEM DEPARTS OUR AREA. THIS WILL BE FOLLOWED BY VISIBILITY AND CEILING CONDITIONS IMPROVING TO VFR AND MVFR RESPECTIVELY BY SUNSET MONDAY EVENING CONTINUING THROUGH MONDAY NIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070- MIZ075-MIZ082 UNTIL NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054 UNTIL NOON MONDAY. WINTER STORM WARNING...MIZ055-MIZ060 UNTIL NOON MONDAY. FREEZING RAIN ADVISORY...MIZ076-MIZ083 UNTIL NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...INNER SAGINAW BAY UNTIL 7 PM TUESDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 7 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 5 PM MONDAY. && $$ SHORT TERM...CONSIDINE LONG TERM....KAHL AVIATION...BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 330 AM EST MON JAN 15 2007 .DISCUSSION... TAKING A LOOK AT THE WATER VAPOR IMAGERY THIS MORNING...THE BULK OF MOISTURE FROM THE SOUTHWEST HAS BEGUN TO INVADE THE UPPER PENINSULA. THE CENTER OF THE SURFACE LOW WAS LOCATED ACROSS SOUTHERN INDIANA...AS WAS CONTINUING TO TRACK NORTHEASTWARD. COMPARING THIS POSITION TO THE MODEL GUIDANCE OF 24 HOURS AGO...IT LOOKS LIKE THE NAM HAD A BETTER HANDLE ON ITS POSITION THAN THE FURTHER EASTWARD GFS. EVEN BETTER THOUGH WAS PROBABLY THE CANADIAN MODEL WHICH HAD ITS 12Z MON POSITION ACROSS SOUTHWESTERN OHIO. IN GENERAL...THE CANADIAN MODEL SEEMS TO BE DOING BETTER THAN MANY OF THE OTHER MODELS CURRENTLY...AND THROUGH MUCH OF THE FORECAST PERIOD. ACROSS THE WESTERN HALF OF THE NATION...HIGH PRESSURE DOMINATED MUCH OF THE AREA. THIS WAS RESULTING IN A LACK OF PRECIPITATION WEST OF A LINE FROM NORTHERN MINNESOTA THROUGH NEBRASKA AND INTO WESTERN TEXAS. HOWEVER...EAST OF THIS LINE THE NATION IS BEING AFFECTED BY THE LARGE STORM SYSTEM CENTERED TO OUR SOUTH. MUCH OF THIS MID JANUARY PRECIPITATION IS FALLING AS RAIN ACROSS THE LOWER 48...WITH A CHANGEOVER TO SNOW ACROSS SOUTHERN MICHIGAN AND NORTHERN ILLINOIS...AND THEN ALONG THE BACK EDGE OF THE PRECIPITATION BAND FURTHER SOUTH. CLOSER TO HOME...THE EASTERN HALF OF THE FORECAST AREA CONTINUES TO SEE NEARLY CONSTANT MODERATE SNOW. THIS AREA IS ALSO IN A FAVORABLE LOCATION...IN THE RIGHT REAR QUADRANT OF AN EXITING 130KT JET AS SHOWN ON THE RUC. THE ACTUAL JET MAX OF 170KT IS LOCATION ACROSS SOUTHERN QUEBEC. THE 500MB TROUGH IS ALSO NEARING THE REGION...CURRENTLY CENTERED ACROSS NORTHEASTERN NORTH DAKOTA THROUGH NORTHEASTERN COLORADO...ATTEMPTING TO PUSH THIS SYSTEM OUT OF THE CENTRAL AND SOUTHERN PLAINS. SURFACE WINDS CURRENTLY 10 TO 30 DEGREES SHOULD BECOME MORE NORTHWARD AFTER 18Z 360 TO 20 DEGREES...AND THEN BACK SLIGHTLY MORE NORTHWESTERLY AROUND AND AFTER 06Z TUESDAY TO 320 TO 350 DEGREES...LIMITING A GOOD FETCH FOR LAKE EFFECT ACROSS THE EASTERN THIRD OF THE LAKE SUPERIOR SHORELINE...WITH THE FOCUS THEN SHIFTING TO THE CENTRAL AND EASTERN UPPER PENINSULA. WITH THAT SAID...NO CHANGES WERE MADE TO THE CURRENT WARNINGS AND ADVISORIES. ALREADY HAVE ABOUT 5 INCHES AT WFO MQT SINCE THE LAKE EFFECT SNOW WARNING WENT INTO EFFECT...SO IT LOOKS LIKE IT SHOULD PAN OUT. OTHERWISE...NEARLY STEADY TEMPERATURES FIGURED TODAY. WARMED UP OVERNIGHT TEMPERATURES TONIGHT ACROSS THE WEST CENTRAL PORTIONS OF THE CWA...GIVEN WARMER GUIDANCE NUMBERS FROM THE MODELS AND THE FACT THAT PLENTY OF CLOUDS SHOULD STILL BE AROUND AT THAT TIME. FOR TUESDAY AFTERNOON...COLDEST AIR WILL BE OVERHEAD ACROSS THE EASTERN HALF OF THE CWA WITH 850MB TEMPS OF -20 TO -22C. WITH THIS AND NORTHWESTERLY SURFACE WINDS...CLOUDS SHOULD HAVE A DIFFICULT TIME EXITING THIS AREA. SO...HAVE PLACED THE WARMEST TEMPERATURES ACROSS THE LAKE MICHIGAN SHORELINE FOR TUESDAY. TUESDAY NIGHT IS EXPECTED TO BE THE COLDEST NIGHT IN THE NEAR FUTURE...WITH GOOD RADIATIONAL COOLING ANTICIPATED PARTICULARLY ACROSS THE SW PENINSULA. SO...STAYED ON THE COOLER SIDE OF GUIDANCE GENERALLY SIDING WITH THE MET HERE. FROM THE 500MB TROUGH CURRENTLY STRETCHING FROM NORTHEAST TO SOUTHWEST ACROSS THE NATIONS MIDSECTION...A CUT OFF LOW IS EXPECTED TO REMAIN. THIS LOW SHOULD DEEPEN OVER THE FOUR CORNERS REGION THROUGH MIDWEEK...BEFORE EJECTING NORTHEASTWARD TOWARDS THE GREAT LAKES. THIS WILL RESULT IN ONLY A SHORT BREAK IN PRECIPITATION FOR OUR AREA. HAVE A BRIEF DRY PERIOD GENERALLY FROM TUESDAY NIGH THOUGH WEDNESDAY. IF THE QUICKER AND SLIGHTLY MORE FAVORED CANADIAN AND UKMET PAN OUT...WE MAY NEED TO ADD POPS BACK A LITTLE QUICKER THAN PREVIOUSLY ANTICIPATED. AS FOR TEMPERATURES WEDNESDAY NIGHT...DISCREPANCIES AND FORECASTER CONFIDENCE BEGINS TO COME INTO PLAY. SO...FEW CHANCES WERE MADE BEYOND THIS POINT. STILL...FOLLOWING A SLIGHTLY CANADIAN AND UKMET QUICKER SOLUTION...OUR LATEST WIND GRIDS DO REFLECT A SLIGHTLY QUICKER FRONT FOR THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 11 PM EST MONDAY FOR MIZ001>004-006-084-085. LAKE EFFECT SNOW WARNING FROM 11 PM EST /10 PM CST/ THIS EVENING TO 11 PM EST /10 PM CST/ MONDAY FOR MIZ005-009. SNOW ADVISORY FROM 1 AM TO 11 PM EST MONDAY FOR MIZ013. SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR MIZ010>012. && $$ KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1255 AM EST MON JAN 15 2007 .AVIATION... PRECIPITATION HAD SPREAD OVER MOST OF SE MICHIGAN AT PRESS TIME, AND ALL TERMINAL SITES. OBSERVATIONS, ESPECIALLY RADAR DATA, SHOW THE AMOUNT AND DURATION WILL HAVE CONSIDERABLY GREATER IMPACTS ON AVIATION THAN WHAT OCCURRED ON SUNDAY. THE DOMINANT PRECIPITATION TYPE WILL BE FREEZING RAIN AT DTW/DET, SLEET AND SNOW AT FNT, AND SNOW AT MBS. THE 06Z-14Z WINDOW STILL LOOKS GOOD FOR THE HEAVIEST PRECIPITATION AT ALL TERMINALS, PUNCTUATED BY IFR CEILING AND VISIBILITY. SOME LIGHT FREEZING DRIZZLE WILL OCCUR DURING THE LATE MORNING AND EARLY AFTERNOON AS DRY AIR MOVES IN THROUGH THE MID LEVELS AND AS THE SYSTEM DEPARTS OUR AREA. THIS WILL BE FOLLOWED BY VISIBILITY AND CEILING CONDITIONS IMPROVING TO VFR AND MVFR RESPECTIVELY BY SUNSET MONDAY EVENING CONTINUING THROUGH MONDAY NIGHT. && .PREV DISCUSSION...ISSUED 951 PM EST SUN JAN 14 2007 UPDATE... OBSERVATIONS AND NEW 00Z MODEL DATA SUPPORTED THE GOING FORECAST WITH NO SIGNIFICANT CHANGES. FORECAST CONCERNS DURING THE OVERNIGHT AND MONDAY MORNING REVOLVED AROUND REFINEMENT OF PRECIPITATION TYPE AND AMOUNT, ALONG WITH THE DEGREE OF ICING IN SOUTH SECTIONS OF THE AREA. THE SYSTEM HAD A LOT GOING FOR IT FROM THE COUPLED UPPER JET SUPPORTING THE MID LEVEL WAVE TO STRONG MOISTURE TRANSPORT AND LOW STATIC STABILITY. THERE IS EVEN SOME CONVECTIVE INSTABILITY INDICATED IN MODEL CROSS SECTIONS NEAR THE OHIO BORDER THROUGH THE EVENT. RAIN AND FREEZING RAIN WAS GETTING UNDERWAY NEAR THE OHIO BORDER SINCE ABOUT 01Z AND SPREADING NORTHWARD ON STRONG MOISTURE TRANSPORT/THETA-E ADVECTION. THIS WILL TRANSITION TO STRONG DYNAMIC FORCING IN THE MIDST OF THE MID LEVEL TROWAL AS THE SURFACE LOW TRACKS TO OUR SOUTH AND EAST. THE STRONG FORCING AND HIGH PRECIPITATION RATES WILL KEEP PRECIPITATION TYPE ON THE COLD END OF THE SPECTRUM IN CENTRAL AND SOUTH LOCATIONS WHERE THE THERMAL PROFILE ALLOWS MIXED PRECIPITATION. ALL SNOW IN THE TRI CITIES AND THUMB LOOKS GOOD WITH BRIEF MIXES OF SLEET. PLAN TO KEEP ACCUMULATIONS OF SNOW AND ICE AS IS WITH THE 00Z MODELS COMING IN MORE IN LINE WITH RESPECT TO QPF. THE ONLY LIMITING FACTOR FOR ICING WILL BE NEAR THE OHIO BORDER WHERE TEMPERATURES WILL HOVER AROUND THE FREEZING MARK NEAR THE LAKE ERIE SHORELINE, AT LEAST UNTIL THE NORTHEAST WINDS INCREASE LATER IN THE NIGHT. PREV DISCUSSION...ISSUED 329 PM EST SUN JAN 14 2007 SHORT TERM...TONIGHT AND MONDAY NOW THAT THE ROUND OF MIXED PRECIPITATION FROM THIS MORNING HAS ENDED...THE ATTENTION TURNS TO A GATHERING STORM OVER THE SOUTHERN PLAINS. A STRONG SHORTWAVE THAT HAS LIFTED AROUND THE BASE OF THE MEAN WESTERN CONUS TROUGH INTO THE SOUTHERN/CENTRAL PLAINS WILL BE RESPONSIBLE FOR AN EXPANDING AREA OF PRECIPITATION...WHICH WILL PROGRESS QUICKLY INTO THE AREA TOWARD MIDNIGHT. THIS FEATURE HAS ALREADY BEEN RESPONSIBLE FOR SIGNIFICANT FREEZING RAIN/SLEET OVER PORTIONS OF THE SOUTHERN PLAINS TODAY...WITH QUITE A BIT OF THUNDER OVER OKLAHOMA/NORTHERN TEXAS. 12Z NAM HAS EXPANDED UPON "ITS" 06Z IDEA OF THROWING MORE MOISTURE AND HENCE QPF INTO THE AREA LATE TONIGHT. THIS LEADS TO WIDESPREAD 75 TO NEAR 1.00 INCH TOTALS. IT ALSO BRINGS IN A STRONG ELEVATED WARM LAYER WITH THIS SURGE...LEADING TO MORE FREEZING RAIN/SLEET. GFS REMAINS MORE SUBDUED IN BOTH RESPECTS. THESE DIFFERENCES DO POSE PROBLEMS IN BOTH PRECIPITATION TYPE/AMOUNT FORECASTS...WITH THE NAM SUPPORTING SOLID WARNING CRITERIA CWA-WIDE...AND GFS NOT. NGM/GEM/LOCALWRF AND VARIOUS EXPERIMENTAL FSL RUC RUNS SUGGEST A BLEND OF THE TWO...WHICH IS NOT TOO SURPRISING. THESE SOLUTIONS SUPPORT WARNING CRITERIA FOR MOST COUNTIES...WITH ONLY A FEW ON THE EDGE. IT IS WORTH NOTING THAT NAM WAS FAR SUPERIOR WITH THE QUARTER INCH BAND OF SNOW/SLEET THAT MOVED THROUGH THE AREA THIS MORNING. GIVEN THIS FACT...AND RADAR TRENDS THROUGH THE PLAINS/MISSISSIPPI VALLEY SO FAR...FEEL THAT GIVING A BIT MORE WEIGHT TO THE NAM IS PROBABLY THE WAY TO GO...SO AN UPGRADE TO VARIOUS WARNINGS SEEMS REASONABLE. EVEN IF A 50/50 COMPROMISE IS USED...MOST COUNTIES SHOULD RECEIVE ENOUGH SNOW AND/OR ICE ACCUMULATIONS TO SUPPORT THE WARNING CRITERIA. SO...THE PLAN IS TO GO WITH A HEAVY SNOW WARNING ACROSS THE SAGINAW VALLEY AND NORTHERN THUMB WHERE PRECIPITATION WILL BE PRETTY MUCH ALL SNOW. COUNTIES ALONG I-69 WILL HAVE A WINTER STORM WARNING FOR THE MIXTURE OF SNOW/SLEET SOME FREEZING RAIN. MEANWHILE...THE MAIN HAZARD FOR THE "M-59" COUNTIES SOUTH WILL BE FREEZING RAIN...SO AN ICE STORM WARNING FITS WELL. THERE MAY BE SOME LOCATIONS NEAR LAKES ERIE/ST CLAIR THAT WILL HOVER AT/ABOVE FREEZING...BUT MOST AREAS SHOULD RECEIVED A PROLONGED FREEZING RAIN EVENT. ALMOST ALL THE THE PRECIPITATION FALLS BETWEEN 04Z-12Z...WITH THE TAIL END OF THE EVENT LINGERING INTO MONDAY MORNING. WARNINGS WILL BE TIMED ACCORDINGLY. LONG TERM...LATE MONDAY THROUGH SUNDAY LAKE ENHANCED SNOWS WITHIN THE RESIDUAL DEFORMATION AXIS SHOULD TRANSITION TO CLEANER BANDED STRUCTURES ACROSS LAKE HURON LATE MONDAY. INVERSION HEIGHTS...AS PER THE 12Z NAM...ARE PROJECTED TO START AROUND 5-6KFT MONDAY AFTERNOON AND LIFT TO 8-9KFT MONDAY NIGHT. THERE WILL BE AMPLE MOISTURE WITHIN AND ABOVE THE CONVECTIVE LAYER TO SUPPORT LAKE-EFFECT SNOWS. THE PRIMARY LIMITING FACTOR WILL BE THAT THE WINDS ARE BACKING THROUGH THE TIME PERIOD...HELPING TO DISTRIBUTE THE SNOWFALL COVERAGE AND REDUCING THE CHANCES THAT ANY ONE LOCATION SEES A PROLONGED PERIOD OF SNOW. BY TUESDAY MORNING THE CONVECTIVE LAYER FLOW SHOULD BE NORTHWESTERLY...KEEPING THE THUMB OUT OF THE SITES. THE ATMOSPHERE WILL SETTLE DOWN ACROSS THE REGION FOR THE REMAINING PORTION OF THE FORECAST. WEAK RIDGING IN THE PRESENCE OF A GENERAL LOWERING OF HEIGHTS ALOFT WILL SET THE STAGE FOR SEASONABLE CONDITIONS. THE NEXT SHOT AT SNOW HOLDS OFF UNTIL THE END OF WEEK...ONCE THE LONG WAVE TROUGHS TRIES TO RE-ESTABLISH ACROSS EASTERN NORTH AMERICA. ONCE THIS OCCURS...NORTHWEST FLOW AND EMBEDDED FAST SHORTWAVES WILL BEGIN TO FREQUENT THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083 UNTIL NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055 UNTIL NOON MONDAY. WINTER STORM WARNING...MIZ060-MIZ061-MIZ062-MIZ063 UNTIL NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING SAGINAW BAY UNTIL 7 AM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 5 PM MONDAY. && $$ AVIATION/UPDATE...BT SHORT TERM...DG LONG TERM....MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 951 PM EST SUN JAN 14 2007 .UPDATE... OBSERVATIONS AND NEW 00Z MODEL DATA SUPPORTED THE GOING FORECAST WITH NO SIGNIFICANT CHANGES. FORECAST CONCERNS DURING THE OVERNIGHT AND MONDAY MORNING REVOLVED AROUND REFINEMENT OF PRECIPITATION TYPE AND AMOUNT, ALONG WITH THE DEGREE OF ICING IN SOUTH SECTIONS OF THE AREA. THE SYSTEM HAD A LOT GOING FOR IT FROM THE COUPLED UPPER JET SUPPORTING THE MID LEVEL WAVE TO STRONG MOISTURE TRANSPORT AND LOW STATIC STABILITY. THERE IS EVEN SOME CONVECTIVE INSTABILITY INDICATED IN MODEL CROSS SECTIONS NEAR THE OHIO BORDER THROUGH THE EVENT. RAIN AND FREEZING RAIN WAS GETTING UNDERWAY NEAR THE OHIO BORDER SINCE ABOUT 01Z AND SPREADING NORTHWARD ON STRONG MOISTURE TRANSPORT/THETA-E ADVECTION. THIS WILL TRANSITION TO STRONG DYNAMIC FORCING IN THE MIDST OF THE MID LEVEL TROWAL AS THE SURFACE LOW TRACKS TO OUR SOUTH AND EAST. THE STRONG FORCING AND HIGH PRECIPITATION RATES WILL KEEP PRECIPITATION TYPE ON THE COLD END OF THE SPECTRUM IN CENTRAL AND SOUTH LOCATIONS WHERE THE THERMAL PROFILE ALLOWS MIXED PRECIPITATION. ALL SNOW IN THE TRI CITIES AND THUMB LOOKS GOOD WITH BRIEF MIXES OF SLEET. PLAN TO KEEP ACCUMULATIONS OF SNOW AND ICE AS IS WITH THE 00Z MODELS COMING IN MORE IN LINE WITH RESPECT TO QPF. THE ONLY LIMITING FACTOR FOR ICING WILL BE NEAR THE OHIO BORDER WHERE TEMPERATURES WILL HOVER AROUND THE FREEZING MARK NEAR THE LAKE ERIE SHORELINE, AT LEAST UNTIL THE NORTHEAST WINDS INCREASE LATER IN THE NIGHT. && .PREV DISCUSSION...ISSUED 648 PM EST SUN JAN 14 2007 AVIATION... ANOTHER ROUND OF MIXED PRECIPITATION IS ON TAP FOR TONIGHT AND MONDAY MORNING IN SE MICHIGAN. THE AMOUNT AND DURATION WILL HAVE GREATER IMPACTS ON AVIATION THAN WHAT OCCURRED THIS MORNING. THE DOMINANT PRECIPITATION TYPE WILL BE FREEZING RAIN AT DTW/DET, SLEET AND SNOW AT FNT, AND SNOW AT MBS. THE WINDOW OF HEAVIEST PRECIPITATION WILL BE 06Z-14Z AT ALL TERMINALS MARKED BY IFR CEILING AND VISIBILITY. SOME LIGHT SNOW AT MBS AND LIGHT FREEZING DRIZZLE ELSEWHERE WILL LINGER TOWARD NOON, FOLLOWED BY VISIBILITY AND CEILING CONDITIONS IMPROVING TO VFR AND MVFR RESPECTIVELY BY SUNSET MONDAY EVENING. PREV DISCUSSION...ISSUED 329 PM EST SUN JAN 14 2007 SHORT TERM...TONIGHT AND MONDAY NOW THAT THE ROUND OF MIXED PRECIPITATION FROM THIS MORNING HAS ENDED...THE ATTENTION TURNS TO A GATHERING STORM OVER THE SOUTHERN PLAINS. A STRONG SHORTWAVE THAT HAS LIFTED AROUND THE BASE OF THE MEAN WESTERN CONUS TROUGH INTO THE SOUTHERN/CENTRAL PLAINS WILL BE RESPONSIBLE FOR AN EXPANDING AREA OF PRECIPITATION...WHICH WILL PROGRESS QUICKLY INTO THE AREA TOWARD MIDNIGHT. THIS FEATURE HAS ALREADY BEEN RESPONSIBLE FOR SIGNIFICANT FREEZING RAIN/SLEET OVER PORTIONS OF THE SOUTHERN PLAINS TODAY...WITH QUITE A BIT OF THUNDER OVER OKLAHOMA/NORTHERN TEXAS. 12Z NAM HAS EXPANDED UPON "ITS" 06Z IDEA OF THROWING MORE MOISTURE AND HENCE QPF INTO THE AREA LATE TONIGHT. THIS LEADS TO WIDESPREAD 75 TO NEAR 1.00 INCH TOTALS. IT ALSO BRINGS IN A STRONG ELEVATED WARM LAYER WITH THIS SURGE...LEADING TO MORE FREEZING RAIN/SLEET. GFS REMAINS MORE SUBDUED IN BOTH RESPECTS. THESE DIFFERENCES DO POSE PROBLEMS IN BOTH PRECIPITATION TYPE/AMOUNT FORECASTS...WITH THE NAM SUPPORTING SOLID WARNING CRITERIA CWA-WIDE...AND GFS NOT. NGM/GEM/LOCALWRF AND VARIOUS EXPERIMENTAL FSL RUC RUNS SUGGEST A BLEND OF THE TWO...WHICH IS NOT TOO SURPRISING. THESE SOLUTIONS SUPPORT WARNING CRITERIA FOR MOST COUNTIES...WITH ONLY A FEW ON THE EDGE. IT IS WORTH NOTING THAT NAM WAS FAR SUPERIOR WITH THE QUARTER INCH BAND OF SNOW/SLEET THAT MOVED THROUGH THE AREA THIS MORNING. GIVEN THIS FACT...AND RADAR TRENDS THROUGH THE PLAINS/MISSISSIPPI VALLEY SO FAR...FEEL THAT GIVING A BIT MORE WEIGHT TO THE NAM IS PROBABLY THE WAY TO GO...SO AN UPGRADE TO VARIOUS WARNINGS SEEMS REASONABLE. EVEN IF A 50/50 COMPROMISE IS USED...MOST COUNTIES SHOULD RECEIVE ENOUGH SNOW AND/OR ICE ACCUMULATIONS TO SUPPORT THE WARNING CRITERIA. SO...THE PLAN IS TO GO WITH A HEAVY SNOW WARNING ACROSS THE SAGINAW VALLEY AND NORTHERN THUMB WHERE PRECIPITATION WILL BE PRETTY MUCH ALL SNOW. COUNTIES ALONG I-69 WILL HAVE A WINTER STORM WARNING FOR THE MIXTURE OF SNOW/SLEET SOME FREEZING RAIN. MEANWHILE...THE MAIN HAZARD FOR THE "M-59" COUNTIES SOUTH WILL BE FREEZING RAIN...SO AN ICE STORM WARNING FITS WELL. THERE MAY BE SOME LOCATIONS NEAR LAKES ERIE/ST CLAIR THAT WILL HOVER AT/ABOVE FREEZING...BUT MOST AREAS SHOULD RECEIVED A PROLONGED FREEZING RAIN EVENT. ALMOST ALL THE THE PRECIPITATION FALLS BETWEEN 04Z-12Z...WITH THE TAIL END OF THE EVENT LINGERING INTO MONDAY MORNING. WARNINGS WILL BE TIMED ACCORDINGLY. LONG TERM...LATE MONDAY THROUGH SUNDAY LAKE ENHANCED SNOWS WITHIN THE RESIDUAL DEFORMATION AXIS SHOULD TRANSITION TO CLEANER BANDED STRUCTURES ACROSS LAKE HURON LATE MONDAY. INVERSION HEIGHTS...AS PER THE 12Z NAM...ARE PROJECTED TO START AROUND 5-6KFT MONDAY AFTERNOON AND LIFT TO 8-9KFT MONDAY NIGHT. THERE WILL BE AMPLE MOISTURE WITHIN AND ABOVE THE CONVECTIVE LAYER TO SUPPORT LAKE-EFFECT SNOWS. THE PRIMARY LIMITING FACTOR WILL BE THAT THE WINDS ARE BACKING THROUGH THE TIME PERIOD...HELPING TO DISTRIBUTE THE SNOWFALL COVERAGE AND REDUCING THE CHANCES THAT ANY ONE LOCATION SEES A PROLONGED PERIOD OF SNOW. BY TUESDAY MORNING THE CONVECTIVE LAYER FLOW SHOULD BE NORTHWESTERLY...KEEPING THE THUMB OUT OF THE SITES. THE ATMOSPHERE WILL SETTLE DOWN ACROSS THE REGION FOR THE REMAINING PORTION OF THE FORECAST. WEAK RIDGING IN THE PRESENCE OF A GENERAL LOWERING OF HEIGHTS ALOFT WILL SET THE STAGE FOR SEASONABLE CONDITIONS. THE NEXT SHOT AT SNOW HOLDS OFF UNTIL THE END OF WEEK...ONCE THE LONG WAVE TROUGHS TRIES TO RE-ESTABLISH ACROSS EASTERN NORTH AMERICA. ONCE THIS OCCURS...NORTHWEST FLOW AND EMBEDDED FAST SHORTWAVES WILL BEGIN TO FREQUENT THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083 UNTIL NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055 UNTIL NOON MONDAY. WINTER STORM WARNING...MIZ060-MIZ061-MIZ062-MIZ063 UNTIL NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING SAGINAW BAY...1 AM MONDAY TO 7 AM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...1 AM MONDAY TO 5 PM MONDAY. && $$ UPDATE/AVIATION...BT SHORT TERM...DG LONG TERM....MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 915 PM EST SUN JAN 14 2007 .UPDATE... ALL FCST DETAILS AND HEADLINES FOR TONIGHT THROUGH MONDAY APPEAR TO BE IN EXCELLENT SHAPE. NO CHANGES TO OUR HEADLINES OR FCST CHANGES WILL BE NECESSARY. 00Z NAM GUIDANCE IS BEGINNING TO ROLL IN AND STILL SUGGESTS POTENTIAL FOR SIGNIFICANT SNOW ACCUMS FROM LATE TONIGHT THROUGH MONDAY MORNING ACROSS OUR CENTRAL AND NORTHERN CWA. THE ICE STORM WARNING FOR OUR SOUTHERN TWO TIERS OF COUNTIES STILL LOOKS GOOD AS WELL. KGRR 88D RADAR TRENDS SUGGEST A MIX OF FZRA AND SLEET WILL DEVELOP ALONG THE I-94 CORRIDOR DURING THE NEXT 1 TO 2 HRS. A SAMPLING OF RUC FCST SOUNDINGS TAKEN ALONG I-94 FROM AZO EAST TO JXN SUGGESTS THAT PCPN DOWN THERE MAY BEGIN AS A PERIOD OF SLEET (AND PERHAPS SNOW) BEFORE WARMER AIR ALOFT (FROM AROUND 750 TO 900 MB) MOVES IN BETWEEN 04Z AND 06Z AS THE SW LLJ INCREASES... THUS INCREASING THE THREAT FOR MDT FZRA AFTER 11 PM THROUGH AROUND DAYBREAK MONDAY. OUR FCST AND ALL HEADLINES LOOK EXCELLENT. WE WILL ISSUE A QUICK ZONE UPDATE JUST TO TWEAK FCST WORDING FOR THE OVERNIGHT PERIOD. && .GRR WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING 10 PM TONIGHT TO NOON MONDAY... ALLEGAN-BARRY-EATON-INGHAM-VAN BUREN-KALAMAZOO-CALHOUN-JACKSON- HEAVY SNOW WARNING MIDNIGHT TONIGHT TO NOON MONDAY... MASON-LAKE-OSCEOLA-CLARE-OCEANA-NEWAYGO-MECOSTA-ISABELLA-MUSKEGON- MONTCALM-GRATIOT- WINTER STORM WARNING 10 PM TONIGHT TO NOON MONDAY... OTTAWA-KENT-IONIA-CLINTON- SMALL CRAFT ADVISORY FOR ST JOE TO MANISTEE MIDNIGHT TONIGHT THROUGH TUESDAY EVENING. && $$ LAURENS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 648 PM EST SUN JAN 14 2007 .AVIATION... ANOTHER ROUND OF MIXED PRECIPITATION IS ON TAP FOR TONIGHT AND MONDAY MORNING IN SE MICHIGAN. THE AMOUNT AND DURATION WILL HAVE GREATER IMPACTS ON AVIATION THAN WHAT OCCURRED THIS MORNING. THE DOMINANT PRECIPITATION TYPE WILL BE FREEZING RAIN AT DTW/DET, SLEET AND SNOW AT FNT, AND SNOW AT MBS. THE WINDOW OF HEAVIEST PRECIPITATION WILL BE 06Z-14Z AT ALL TERMINALS MARKED BY IFR CEILING AND VISIBILITY. SOME LIGHT SNOW AT MBS AND LIGHT FREEZING DRIZZLE ELSEWHERE WILL LINGER TOWARD NOON, FOLLOWED BY VISIBILITY AND CEILING CONDITIONS IMPROVING TO VFR AND MVFR RESPECTIVELY BY SUNSET MONDAY EVENING. && .PREV DISCUSSION...ISSUED 329 PM EST SUN JAN 14 2007 SHORT TERM...TONIGHT AND MONDAY NOW THAT THE ROUND OF MIXED PRECIPITATION FROM THIS MORNING HAS ENDED...THE ATTENTION TURNS TO A GATHERING STORM OVER THE SOUTHERN PLAINS. A STRONG SHORTWAVE THAT HAS LIFTED AROUND THE BASE OF THE MEAN WESTERN CONUS TROUGH INTO THE SOUTHERN/CENTRAL PLAINS WILL BE RESPONSIBLE FOR AN EXPANDING AREA OF PRECIPITATION...WHICH WILL PROGRESS QUICKLY INTO THE AREA TOWARD MIDNIGHT. THIS FEATURE HAS ALREADY BEEN RESPONSIBLE FOR SIGNIFICANT FREEZING RAIN/SLEET OVER PORTIONS OF THE SOUTHERN PLAINS TODAY...WITH QUITE A BIT OF THUNDER OVER OKLAHOMA/NORTHERN TEXAS. 12Z NAM HAS EXPANDED UPON "ITS" 06Z IDEA OF THROWING MORE MOISTURE AND HENCE QPF INTO THE AREA LATE TONIGHT. THIS LEADS TO WIDESPREAD 75 TO NEAR 1.00 INCH TOTALS. IT ALSO BRINGS IN A STRONG ELEVATED WARM LAYER WITH THIS SURGE...LEADING TO MORE FREEZING RAIN/SLEET. GFS REMAINS MORE SUBDUED IN BOTH RESPECTS. THESE DIFFERENCES DO POSE PROBLEMS IN BOTH PRECIPITATION TYPE/AMOUNT FORECASTS...WITH THE NAM SUPPORTING SOLID WARNING CRITERIA CWA-WIDE...AND GFS NOT. NGM/GEM/LOCALWRF AND VARIOUS EXPERIMENTAL FSL RUC RUNS SUGGEST A BLEND OF THE TWO...WHICH IS NOT TOO SURPRISING. THESE SOLUTIONS SUPPORT WARNING CRITERIA FOR MOST COUNTIES...WITH ONLY A FEW ON THE EDGE. IT IS WORTH NOTING THAT NAM WAS FAR SUPERIOR WITH THE QUARTER INCH BAND OF SNOW/SLEET THAT MOVED THROUGH THE AREA THIS MORNING. GIVEN THIS FACT...AND RADAR TRENDS THROUGH THE PLAINS/MISSISSIPPI VALLEY SO FAR...FEEL THAT GIVING A BIT MORE WEIGHT TO THE NAM IS PROBABLY THE WAY TO GO...SO AN UPGRADE TO VARIOUS WARNINGS SEEMS REASONABLE. EVEN IF A 50/50 COMPROMISE IS USED...MOST COUNTIES SHOULD RECEIVE ENOUGH SNOW AND/OR ICE ACCUMULATIONS TO SUPPORT THE WARNING CRITERIA. SO...THE PLAN IS TO GO WITH A HEAVY SNOW WARNING ACROSS THE SAGINAW VALLEY AND NORTHERN THUMB WHERE PRECIPITATION WILL BE PRETTY MUCH ALL SNOW. COUNTIES ALONG I-69 WILL HAVE A WINTER STORM WARNING FOR THE MIXTURE OF SNOW/SLEET SOME FREEZING RAIN. MEANWHILE...THE MAIN HAZARD FOR THE "M-59" COUNTIES SOUTH WILL BE FREEZING RAIN...SO AN ICE STORM WARNING FITS WELL. THERE MAY BE SOME LOCATIONS NEAR LAKES ERIE/ST CLAIR THAT WILL HOVER AT/ABOVE FREEZING...BUT MOST AREAS SHOULD RECEIVED A PROLONGED FREEZING RAIN EVENT. ALMOST ALL THE THE PRECIPITATION FALLS BETWEEN 04Z-12Z...WITH THE TAIL END OF THE EVENT LINGERING INTO MONDAY MORNING. WARNINGS WILL BE TIMED ACCORDINGLY. LONG TERM...LATE MONDAY THROUGH SUNDAY LAKE ENHANCED SNOWS WITHIN THE RESIDUAL DEFORMATION AXIS SHOULD TRANSITION TO CLEANER BANDED STRUCTURES ACROSS LAKE HURON LATE MONDAY. INVERSION HEIGHTS...AS PER THE 12Z NAM...ARE PROJECTED TO START AROUND 5-6KFT MONDAY AFTERNOON AND LIFT TO 8-9KFT MONDAY NIGHT. THERE WILL BE AMPLE MOISTURE WITHIN AND ABOVE THE CONVECTIVE LAYER TO SUPPORT LAKE-EFFECT SNOWS. THE PRIMARY LIMITING FACTOR WILL BE THAT THE WINDS ARE BACKING THROUGH THE TIME PERIOD...HELPING TO DISTRIBUTE THE SNOWFALL COVERAGE AND REDUCING THE CHANCES THAT ANY ONE LOCATION SEES A PROLONGED PERIOD OF SNOW. BY TUESDAY MORNING THE CONVECTIVE LAYER FLOW SHOULD BE NORTHWESTERLY...KEEPING THE THUMB OUT OF THE SITES. THE ATMOSPHERE WILL SETTLE DOWN ACROSS THE REGION FOR THE REMAINING PORTION OF THE FORECAST. WEAK RIDGING IN THE PRESENCE OF A GENERAL LOWERING OF HEIGHTS ALOFT WILL SET THE STAGE FOR SEASONABLE CONDITIONS. THE NEXT SHOT AT SNOW HOLDS OFF UNTIL THE END OF WEEK...ONCE THE LONG WAVE TROUGHS TRIES TO RE-ESTABLISH ACROSS EASTERN NORTH AMERICA. ONCE THIS OCCURS...NORTHWEST FLOW AND EMBEDDED FAST SHORTWAVES WILL BEGIN TO FREQUENT THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083...10 PM SUNDAY TO NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054- MIZ055...MIDNIGHT MONDAY TO NOON MONDAY. WINTER STORM WARNING...MIZ060-MIZ061-MIZ062-MIZ063...MIDNIGHT MONDAY TO NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING SAGINAW BAY...1 AM MONDAY TO 7 AM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...1 AM MONDAY TO 5 PM MONDAY. && $$ AVIATION...BT SHORT TERM...DG LONG TERM....MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 430 PM EST SUN JAN 14 2007 .SYNOPSIS AND SHORT TERM... WATER VAPOR LOOP AND RUC/LAPS ANALYSIS SHOW SOUTHWEST FLOW ALOFT BUT COLDER AIR REMAINS ENTRENCHED OVR PLAINS INTO UPR LAKES. FRONTAL BOUNDARY HAS SLIPPED SOUTH OF UPR MI ATTM. WINDS BECOMING NORTHERLY IN WAKE OF TROUGH. DESPITE LOW INVERSION AROUND 3 KFT PER MIDDAY TAMDAR DATA AT CYQT AND KSAW...LK EFFECT HAS BEEN PROFICIENT WITH SOME ACCUMS REPORTED BY SPOTTER IN MOHAWK IN HOUGHTON COUNTY. LATEST RADAR AND VIS SAT EVEN SHOW ENHANCED CONVERGENCE BAND BTWN MQT AND STDM4 OVR SCNTRL LK SUPERIOR. TO THE SW OF UPR LAKES LARGE AREA OF MOSTLY SNOW IS LIFTING NE ACROSS NEB AND WESTERN IA. THIS SNOW IS ASSOCIATED WITH MID LEVEL LOW IN CNTRL KS AND IT NOW LOOKS LIKE THIS SNOW WILL MAKE IT INTO UPR MI LATE TONIGHT INTO MONDAY. SNOW AMOUNTS AND HEADLINES ARE MAIN CONCERNS IN SHORT TERM. NORTHERLY FLOW TONIGHT WITH TEMPS AT TOP OF INVERSION AROUND -17C WILL KEEP LK EFFECT GOING THROUGH EVENING. NOTED CONVERGENCE BAND MAY ENHANCE SNOWFALL BRIEFLY THIS EVENING OVR NCNTRL. OTHERWISE... EXPECT SNOW TO INCREASE AFTER MIDNIGHT AS SYNOPTIC SNOW ARRIVES FM THE SOUTH. HOW FAR NORTH WILL SHIELD OF DEEPER MOISTURE/UPR LEVEL FORCING AND SYNOPTIC SNOW SURGE WAS MAIN QUESTION OF THE SHIFT. UNLIKE YDY FOR THE MOST PART GFS/NAM/UKMET/ECMWF/CANADIAN GEM ARE ALL ON SAME PAGE. BLEND OF QPF OUTPUT GIVES MOST AREAS A SOLID 0.20 TO 0.25 INCHES OF LIQUID 00Z MON THROUGH 00Z TUE. USING BUFKIT COBB SNOW-WATER RATIOS AND UWM ROEBBER SNOW RATIO FORECAST PAGE GIVES HIGHER RATIO THAN TYPICAL SYNOPTIC EVENT...MORE IN LINE WITH 15-20 TO 1. IN GENERAL...THIS GIVES TOTAL AMOUNTS OF 3 TO 5 INCHES OVR SOUTHERN TIER...WHICH JUSTIFIES AN ADVY THROUGH LATE TOMORROW. COORD THIS WITH DLH AND GRB. BASED ON AIRMASS OVERHEAD AND WAY LK EFFECT HAS TURNED OUT LAST FEW DAYS...EXPECT EVEN HIGHER RATIOS OVR PRONE LK EFFECT AREAS. LOWER LEVEL WINDS THROUGH H85 ON AVERAGE FM 360 DIRECTION...ALTHOUGH NAM/CANADIAN GEM ARE A BIT MORE TOWARD 030. INVERSION HEIGHTS ARE FAIRLY LOW...5-7KFT...BUT WITH DEEP MOISTURE PRESENT...AND TEMPS AT TOP OF INVERSION TOWARD -18C...SIGNIFICANT LAKE CONTRIBUTION IS EXPECTED. UPGRADED TO LK EFFECT SNOW WARNING FOR FAR WEST AND NCNTRL UPR MI. SOME LOCALIZED AREAS MAY SEE AROUND A FOOT OF SNOW FM THE EVENT. ALTHOUGH WINDS ARE NOT AS FAVORABLE FOR OTHER ZONES NEAR LK SUPERIOR...SYNOPTIC MOISTURE AND SOME LAKE CONTRIBUTION TIPS SCALES TOWARD ADVY FOR ALL BUT LUCE COUNTY AS NORTHEAST WINDS DO NOT PRODUCE PROVIDE SUITABLE FETCH FOR LK INDUCED CONVECTION. ONE NOTE ABOUT THE KEWEENAW. AIRMASS LURKING OVER NORTHERN LAKE SUPERIOR IS QUITE DRY AND SOUNDINGS EVEN FM THE HIGHER RESOLUTION MODELS INDICATE SHARP CUTOFF TO DEEPER MOISTURE. THIS MAY IMPACT INTENSITY OF INDIVIDUAL SNOW BANDS. STILL...SINCE LAKE IS SHOWING NO ICE ON IT AND WATER TEMPS ARE RUNNING +3C TO +4C AND THERE IS SOME SYNOPTIC SUPPORT...BELIEVE THE HIGHER TERRAIN OF NORTHERN KEWEENAW AND TOWARD ONTONAGON COUNTY COULD EEK INTO ADVY CRITERIA. ALL LK SUPERIOR HEADLINES EXPIRE LATE MON EVENING. .LONG TERM...(MON NIGHT THROUGH SUNDAY) MON NIGHT...AS THE SYNOPTIC SCALE SUPPORT WITH THE QVECTOR CONV WITH THE MID LVL TROF AND DEEPER MOISTURE DEPARTS THE SNOW OVER SOUTH UPPER MICHIGAN WILL TAPER OFF QUICKLY EARLY IN THE EVENING...AND THE LES INTENSITY NORTH WILL DIMINISH SIGNIFICANTLY. HOWEVER...THE NAM AND GFS CONTINUE TO INDICATE DECENT LOW LEVEL CONV INTO N CNTRL UPPER MI (VCNTY MARQEUTTE) AND OVER THE WEST(NEAR KIWD) THROUGH 06Z. TEMPS OF -18C NEAR THE TOP OF THE 4K FT INVERSION SHOULD STILL FAVOR BANDS OF LIGHT TO MODERATE LES. AS THE WINDS BACK TO NW OVERNIGHT THE LES FOCUS WILL SHIFT INTO AREAS FROM KP53 EASTWARD. THE SHORTER FETCH INTO W UPR MI AND EVEN LOWER INVERSION HEIGHTS SHOULD ALLOW LES TO TAPER OFF TO JUST LIGHT SNOW OR FLURRIES WITH ONLY MINOR AMOUNTS AFT 06Z. TUE...ALTHOUGH THE SFC RDG WILL BUILD INTO THE AREA...LAKE INDUCED TROUGHING WILL KEEP NW OR NW WINDS GOING WITH BEST LOW LVL CONV EAST OF MARQEUTTE. BY AFTERNOON...THE COMBINATION BACKING WINDS AND ADDITIONAL LOW LEVEL DRYING...WAA AND BACKING WINDS SHOULD BRING AN END TO ANY SIGNIFICANT LES. THE EXCEPTION WILL BE OVER THE FAR E CWA WHERE LONGER FETCH AND CLOSER PROXIMITY TO THE DEPARTING 850 MB THERMAL TROF WILL KEEP LIGHT LES GOING. WED INTO THU...GLBL MDLS ARE CONSISTENT WITH PATTERN WITH STRONG WAA DEVELOPING AS THE SFC RDG SINKS SE AND A PLAINS SHRTWV AND SFC TROF MOVE TOWARD THE AREA. AS A RESULT...TEMPS SHOULD REBOUND TO READINGS AOA NORMAL WED. MODERATE QVECTOR CONV WITH THE PROMINENT 500 MB TROF WARRANT AT LEAST CHANCE POPS ACROSS THE CWA WITH LES CHANCES INCREASING BY LATE THU AS CAA TAKES OVER BEHIND THE SFC FRONT/TROF AS 850 MB TEMPS FALL TO NEAR -15C. FRI THROUGH SUN...GOOD LES CHANCES CONTINUE IN GENERAL FOR NW FLOW FAVORED LOCATIONS. NW NORTHERN STREAM FLOW WILL BRING A FEW CLIPPER SHRTWVS THROUGH THE AREA BUT LESS CERTAINTY WITH TIMING/STRENGTH OF THESE FEATURES AND IMPACT ON WIND DIRECTION. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 11 PM EST MONDAY FOR MIZ001>004-006-084-085. LAKE EFFECT SNOW WARNING FROM 11 PM EST /10 PM CST/ THIS EVENING TO 11 PM EST /10 PM CST/ MONDAY FOR MIZ005-009. SNOW ADVISORY FROM 1 AM TO 11 PM EST MONDAY FOR MIZ013. SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR MIZ010>012. && $$ JLA(SHORT TERM) JLB(LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 329 PM EST SUN JAN 14 2007 .SHORT TERM...TONIGHT AND MONDAY NOW THAT THE ROUND OF MIXED PRECIPITATION FROM THIS MORNING HAS ENDED...THE ATTENTION TURNS TO A GATHERING STORM OVER THE SOUTHERN PLAINS. A STRONG SHORTWAVE THAT HAS LIFTED AROUND THE BASE OF THE MEAN WESTERN CONUS TROUGH INTO THE SOUTHERN/CENTRAL PLAINS WILL BE RESPONSIBLE FOR AN EXPANDING AREA OF PRECIPITATION...WHICH WILL PROGRESS QUICKLY INTO THE AREA TOWARD MIDNIGHT. THIS FEATURE HAS ALREADY BEEN RESPONSIBLE FOR SIGNIFICANT FREEZING RAIN/SLEET OVER PORTIONS OF THE SOUTHERN PLAINS TODAY...WITH QUITE A BIT OF THUNDER OVER OKLAHOMA/NORTHERN TEXAS. 12Z NAM HAS EXPANDED UPON "ITS" 06Z IDEA OF THROWING MORE MOISTURE AND HENCE QPF INTO THE AREA LATE TONIGHT. THIS LEADS TO WIDESPREAD .75 TO NEAR 1.00 INCH TOTALS. IT ALSO BRINGS IN A STRONG ELEVATED WARM LAYER WITH THIS SURGE...LEADING TO MORE FREEZING RAIN/SLEET. GFS REMAINS MORE SUBDUED IN BOTH RESPECTS. THESE DIFFERENCES DO POSE PROBLEMS IN BOTH PRECIPITATION TYPE/AMOUNT FORECASTS...WITH THE NAM SUPPORTING SOLID WARNING CRITERIA CWA-WIDE...AND GFS NOT. NGM/GEM/LOCALWRF AND VARIOUS EXPERIMENTAL FSL RUC RUNS SUGGEST A BLEND OF THE TWO...WHICH IS NOT TOO SURPRISING. THESE SOLUTIONS SUPPORT WARNING CRITERIA FOR MOST COUNTIES...WITH ONLY A FEW ON THE EDGE. IT IS WORTH NOTING THAT NAM WAS FAR SUPERIOR WITH THE QUARTER INCH BAND OF SNOW/SLEET THAT MOVED THROUGH THE AREA THIS MORNING. GIVEN THIS FACT...AND RADAR TRENDS THROUGH THE PLAINS/MISSISSIPPI VALLEY SO FAR...FEEL THAT GIVING A BIT MORE WEIGHT TO THE NAM IS PROBABLY THE WAY TO GO...SO AN UPGRADE TO VARIOUS WARNINGS SEEMS REASONABLE. EVEN IF A 50/50 COMPROMISE IS USED...MOST COUNTIES SHOULD RECEIVE ENOUGH SNOW AND/OR ICE ACCUMULATIONS TO SUPPORT THE WARNING CRITERIA. SO...THE PLAN IS TO GO WITH A HEAVY SNOW WARNING ACROSS THE SAGINAW VALLEY AND NORTHERN THUMB WHERE PRECIPITATION WILL BE PRETTY MUCH ALL SNOW. COUNTIES ALONG I-69 WILL HAVE A WINTER STORM WARNING FOR THE MIXTURE OF SNOW/SLEET SOME FREEZING RAIN. MEANWHILE...THE MAIN HAZARD FOR THE "M-59" COUNTIES SOUTH WILL BE FREEZING RAIN...SO AN ICE STORM WARNING FITS WELL. THERE MAY BE SOME LOCATIONS NEAR LAKES ERIE/ST CLAIR THAT WILL HOVER AT/ABOVE FREEZING...BUT MOST AREAS SHOULD RECEIVED A PROLONGED FREEZING RAIN EVENT. ALMOST ALL THE THE PRECIPITATION FALLS BETWEEN 04Z-12Z...WITH THE TAIL END OF THE EVENT LINGERING INTO MONDAY MORNING. WARNINGS WILL BE TIMED ACCORDINGLY. && .LONG TERM...LATE MONDAY THROUGH SUNDAY LAKE ENHANCED SNOWS WITHIN THE RESIDUAL DEFORMATION AXIS SHOULD TRANSITION TO CLEANER BANDED STRUCTURES ACROSS LAKE HURON LATE MONDAY. INVERSION HEIGHTS...AS PER THE 12Z NAM...ARE PROJECTED TO START AROUND 5-6KFT MONDAY AFTERNOON AND LIFT TO 8-9KFT MONDAY NIGHT. THERE WILL BE AMPLE MOISTURE WITHIN AND ABOVE THE CONVECTIVE LAYER TO SUPPORT LAKE-EFFECT SNOWS. THE PRIMARY LIMITING FACTOR WILL BE THAT THE WINDS ARE BACKING THROUGH THE TIME PERIOD...HELPING TO DISTRIBUTE THE SNOWFALL COVERAGE AND REDUCING THE CHANCES THAT ANY ONE LOCATION SEES A PROLONGED PERIOD OF SNOW. BY TUESDAY MORNING THE CONVECTIVE LAYER FLOW SHOULD BE NORTHWESTERLY...KEEPING THE THUMB OUT OF THE SITES. THE ATMOSPHERE WILL SETTLE DOWN ACROSS THE REGION FOR THE REMAINING PORTION OF THE FORECAST. WEAK RIDGING IN THE PRESENCE OF A GENERAL LOWERING OF HEIGHTS ALOFT WILL SET THE STAGE FOR SEASONABLE CONDITIONS. THE NEXT SHOT AT SNOW HOLDS OFF UNTIL THE END OF WEEK...ONCE THE LONG WAVE TROUGHS TRIES TO RE-ESTABLISH ACROSS EASTERN NORTH AMERICA. ONCE THIS OCCURS...NORTHWEST FLOW AND EMBEDDED FAST SHORTWAVES WILL BEGIN TO FREQUENT THE REGION. && .PREV DISCUSSION...ISSUED 1208 PM EST SUN JAN 14 2007 AVIATION... FIRST WAVE OF SNOW/SLEET/FREEZING RAIN IS MOVING OUT OF THE AREA AND SHOULD PRETTY MUCH BE CLEAR OF THE FORECAST SITES BY 18Z...LEAVING VARIOUS LEVELS OF STRATUS...WITH CEILINGS EITHER SIDE OF 1000 FEET. THIS LULL IS RATHER BRIEF...HOWEVER...AS A MUCH STRONG WAVE WITH A BETTER TAP OF GULF MOISTURE IS ALREADY HEADING OUT OF THE SOUTHERN PLAINS TOWARDS THE LOWER LAKES/OHIO VALLEY. THIS WILL SPREAD A MUCH LARGER AREA OF PRECIPITATION INTO THE AREA BY AROUND MIDNIGHT...W/ HEAVIER AMOUNTS EXPECTED CWA-WIDE. WILL USE A 12Z NAM SOLUTION THAT IS MODIFIED SLIGHTLY TOWARD THE FURTHER SOUTH/COLDER GFS TO GIVE A FIRST APPROXIMATION OF PRECIPITATION TYPE. THIS GIVES KMBS PRETTY MUCH ALL SNOW...KFNT A MIX OF SN/PL AND PERHAPS SOME FZRA...WHILE KDET/KDTW RECEIVE MAINLY FZRA...W/ TEMPERATURES EVENTUALLY EDGING CLOSE TO OR ABOVE FREEZING BY MONDAY MORNING. EXPECT CONDITIONS TO DETERIORATE VERY QUICKLY AROUND MIDNIGHT...WITH SIGNIFICANT SNOW AND/OR ICE ACCUMULATIONS EXPECTED. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...ICE STORM WARNING...MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083...10 PM SUNDAY TO NOON MONDAY. HEAVY SNOW WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054- MIZ055...MIDNIGHT MONDAY TO NOON MONDAY. WINTER STORM WARNING...MIZ060-MIZ061-MIZ062-MIZ063...MIDNIGHT MONDAY TO NOON MONDAY. LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT H MONDAY TO 7 AM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444...1 AM MONDAY TO 5 PM MO && $$ SHORT TERM...DG LONG TERM....MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 550 AM EST SUN JAN 14 2007 .DISCUSSION... WATER VAPOR IMAGERY INDICATED PLENTY OF MOISTURE STRETCHING FROM NORTHWESTERN MEXICO...INTO THE NEW ENGLAND STATES ALONG AN ELONGATED LINE OF LOW PRESSURE. SOME DRY AIR WAS ATTEMPTING TO SLIDE INTO SOUTHERN ARIZONA AND NEW MEXICO. THE RUC SHOWED THE 500MB CLOSED LOW STRETCHING FROM WYOMING THROUGH SOUTHERN UTAH. THE 250MB JET...WITH A MAX SPEED OF 80KT WAS DIVING SOUTHWARD ACROSS THE PACIFIC COASTLINE...BEFORE KINKING BACK NORTHEASTWARD AT 110KT FROM NORTHEASTERN NEW MEXICO THROUGH NEBRASKA...AND EASTWARD THROUGH NEW YORK AT 130KT. CLOSER TO HOME...A WEAK COLD FRONT WAS SLIDING SOUTHEASTWARD ACROSS SOUTHERN LAKE SUPERIOR. COLDEST -35C 850MB AIR WILL REMAIN OUT OF THE AREA...CURRENTLY SLIDING EASTWARD OVER NORTHWESTERN JAMES BAY. THIS IS MUCH COOLER THAN OUR -12 TO -15C OVER THE UPPER PENINSULA. STILL THIS WILL BE ENOUGH FOR LIGHT LAKE EFFECT PRECIPITATION TODAY...GENERALLY AROUND AN INCH OR LESS. THE RELATIVELY DRY COLD FRONT WILL CONTINUE TO SLOWLY SWEEP ACROSS THE CWA THIS MORNING...WITH ENHANCED LOW LEVEL CONVERGENCE AND VEERING WINDS AND INVERSION HEIGHTS BETWEEN 3 AND 4FT. THE BEST QVECTOR CONVERGENCE IS REMAINING WELL TO THE NORTH...SO CONDITIONS WILL BE MARGINAL FOR MORE THEN LIGHT LES AS PREVIOUSLY STATED...AROUND AN INCH OR LESS. LOOKING AT THE IR SATELLITE...BANDS ARE BEGINNING TO FORM ACROSS THE NORTHERN HALF OF LAKE SUPERIOR. THE SHOW SHOWERS SHOULD DIMINISH AND SPREAD OUT ACROSS THE AREA LATE IN THE AFTERNOON AS HIGH PRESSURE SINKS SOUTHEASTWARD FROM CENTRAL SASKATCHEWAN. SOME VARIABILITY STILL REMAINS WITH THE FORECAST TRACK OF THE SURFACE LOW THAT WE ARE MOST INTERESTED IN. THIS ONE IS MORE DIFFICULT TO PIN DOWN ON THE SURFACE MAP AS IT IS MORE ELONGATED...STRETCHING ACROSS SOUTHERN TEXAS...NORTHEASTWARD ALONG THE MISSISSIPPI RIVER VALLEY AND INTO THE SOUTHERN OHIO VALLEY. BY 12Z MONDAY...MODELS ARE HAVING A TOUGH TIME FIGURING OUT WHERE THE CENTER OF LOW PRESSURE WILL BE LOCATED. IT WILL BE SOMEWHERE IN THE CENTRAL TO NORTHERN OHIO VALLEY...EITHER ACROSS NE OHIO (00Z NAM SOLUTION)...SOUTHWESTERN OHIO (12Z CANADIAN)...NORTHWESTERN PENNSYLVANIA (00Z RUC)...OR NORTHERN WEST VIRGINIA (18Z AND 00Z GFS). YES...THE LOCATION WILL HAVE AN AFFECT ON OUR REGION...AS THE NORTHERN SHIELD OF PRECIPITATION HEADS OUR WAY AFTER 03Z MONDAY...AND POSSIBLY MAKING IT AS FAR NORTH AS HOUGHTON. ADDED LIKELY POPS FOR SOUTHERN AREA MONDAY AS THE BULK OF PRECIPITATION HEADS OUR WAY. PLENTY OF CLOUDS WILL ALSO BEGIN TO INVADE SUNDAY NIGHT...AND REMAIN OVER THE CWA THROUGH MONDAY NIGHT. ALSO FOR THIS TIME PERIOD...WE WILL BE MONITORING LAKE SUPERIOR AND WINDS...AS A LAKE EFFECT SNOW ADVISORY HAS BEEN POSTED FOR MARQUETTE AND ALGER COUNTIES FROM 4 AM UNTIL 7 PM MONDAY. BUFKIT SOUNDING INDICATE THAT THE NAM HAS DEEPER MOISTURE AVAILABLE NEAR THE MARQUETTE AREA...PARTICULARLY WHEN COMPARED TO THE DRIER SOUNDING AT HOUGHTON. THE NAM AND GFS ARE PRETTY CLOSE WITH THEIR SFC WINDS...UNTIL MONDAY NIGHT WHEN THE NAM BECOMES MORE NORTHWESTERLY GIVEN THE DEEPER AND MORE WESTWARD SURFACE LOW ACROSS THE MID ATLANTIC...AND THE LARGE AREA OF HIGH PRESSURE APPROACHING FROM THE WEST. IN GENERAL...HAVE ANGLED THE FORECAST MORE IN LINE WITH THE MORE MOIST GFS FOR THIS PERIOD. WILL NEED TO MONITOR THE EXTREME WESTERN PORTIONS OF THE CWA FOR A POSSIBLE EXPANSION OF THE ADVISORY...WITH IMPRESSIVE LOOKING SOUNDING INFO AT IWD TONIGHT AS WELL. THEN FOR MONDAY NIGHT INTO TUESDAY...AS HIGH PRESSURE TRIES TO INVADE FROM THE WEST...A POSITIVELY TILTED UPPER LEVEL TROUGH WILL BE SLIDING ACROSS THE UPPER MIDWEST. SHIFTING WINDS WILL NOT BE FAVORABLE FOR ANY SUSTAINED LAKE EFFECT SNOW WITH HEAVY SNOWFALL WITH THIS SYSTEM. HOWEVER...HAVE STILL KEPT LIKELY POPS ACROSS THE LAKE SHORE...WITH AN INCH OR TWO OF SNOW POSSIBLE. OTHER CHANGES FURTHER OUT IN THE FORECAST...DRIED THINGS OUT EARLIER TUESDAY AFTERNOON INTO WEDNESDAY. ALSO WARMED UP TEMPERATURE DAY 4 (WEDNESDAY) BY SEVERAL DEGREES...GIVEN SOUTHWESTERLY FLOW AND ONLY SCT CLOUDS MAINLY ACROSS THE NORTHERN TIER OF THE FORECAST AREA DURING THE AFTERNOON HOURS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR MIZ005-006. && $$ KF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 1104 AM CST MON JAN 15 2007 .UPDATE...CANCELLED SNOW ADVISORY WILL LITTLE OR NO ADDITIONAL ACCUMULATION EXPECTED. WILL KEEP LAKE EFFECT WARNING OUT THROUGH 6PM (AT LEAST). BANDS ARE REALLY ISOLATED IN NATURE AND HARD TO LOCATE. WITH DEPARTURE OF MID LEVEL CLOUDS...VISIBLE SATELLITE IMAGERY SHOULD GIVE A MUCH BETTER VIEW OF BANDS THIS AFTERNOON. KIWD OBSERVATION HAS DROPPED TO 1/2 MILE THIS PAST HOUR...AND REPORTS FROM SNOW OBSERVERS INDICATED SOME HEAVY SNOW STILL ONGOING ATTM...ESPECIALLY ACROSS NORTHERN IRON AND NORTHEAST ASHLAND COUNTIES. BAYFIELD COUNTY IS A BIT MORE PROBLEMATIC...WITH REPORTS GENERALLY RANGING FROM THE 2.5 TO 3 INCHES. EXPECT POSSIBLE BORDERLINE WARNING CRITERIA IN VERY ISOLATED LOCATIONS THERE. REST OF FORECAST LOOKS ON TRACK WITH VERY COLD NIGHT ON TAP TONIGHT FOR THE NORTHLAND. && .PREV DISCUSSION... /ISSUED 429 AM CST MON JAN 15 2007/ UPDATE... NO SNOWFALL SPOTTERS HAVE REPORTED OVERNIGHT. HOWEVER...CALLS TO COUNTY LAW ENFORCEMENT HAVE INFORMED ME THAT NEW SNOWFALL OF 2 TO 4 INCHES FELL OVERNIGHT ACROSS WASHBURN...SAWYER AND PRICE COUNTIES. SINCE PINE...DOUGLAS AND BURNETT COUNTIES ALL REPORTED AROUND AN INCH OVERNIGHT...AND THE MAIN FORCING AND STRONGER RADAR RETURNS HAVE ALL PROCEEDED TO THE EAST..CANCELLED THE SN ADVISORY FOR THESE COUNTIES. DOUGLAS COUNTY MAY SEE SOME ACCUMULATION YET DUE TO LAKE EFFECT...WITH UP TO 2 INCHES OF ADDITIONAL ACCUMULATION NEAR LAKE SUPERIOR. GRANING PREV DISCUSSION... /ISSUED 314 AM CST MON JAN 15 2007/ DISCUSSION... SYNOPTIC SNOW CONTINUES TO TRACK NE ACROSS NRN WISCONSIN WHILE LES SNOW IS FOUND ALONG THE SNOW BELT REGION OF THE SOUTH SHORE. FIRST FCST FOCUS ON TIMING THE BACK EDGE OF THE SNOW...AS WELL AS TOTAL SN AMOUNTS. NO SIG CHANGES TO FCST. PREVIOUS FCST IN GOOD SHAPE WITH LIKELY/DEF POPS ACROSS WI ZONES WHERE VARIOUS HEADLINES ARE IN EFFECT. THE GFS/NAM AGREE THAT THE FORCING ASSOCIATED WITH THE SYNOPTIC SN WILL MOVE EAST AND DIMINISH OVER THE ERN FA THROUGH THIS MORNING...TAPERING OFF FROM WEST TO EAST THIS AFTERNOON. WILL KEEP HEADLINE TIMING AS IS. THE GREATEST SNOWFALL AMOUNTS AWAY FROM LAKE SUPERIOR WILL BE ACROSS THE FAR SE ZONES /SAWYER AND PRICE COUNTIES/. SECOND FCST DIFFICULTY...LES TODAY. CURRENT SFC OBSERVATIONS AND LOCAL WEB CAMS SHOW THAT THE LES HAS WEAKENED. ALTHOUGH THERE ARE LIGHT RADAR RETURNS...AND THE COLD AIR AND TRAJECTORIES ARE IN PLACE...CIGS ARE INCREASING ALONG THE SOUTH SHORE. THE 08Z MSAS AND NAM12 ANALYSIS ARE PICKING UP ON A VERY TIGHT LW LVL RH GRADIENT SITTING PARALLEL AND JUST TO THE NORTH OF THE SOUTH SHORE OF LS. THIS ARCTIC DRY-LINE IS DEPICTED IN BOTH THE 1000-850 MB AND 925-850 MB RH FIELDS...WHERE VALUES OF 35-40 PERCENT ARE FOUND NORTH OF THE THE BOUNDARY ALONG THE NORTH SHORE...AND OVER 80 PERCENT RH JUST INLAND IN NW WIS. THE NAM/RUC BRING THIS DRY AIR OVER THE WRN TIP OF LS AND INTO THE FAR NW CORNER OF WIS THROUGH 12Z...THEN RETREAT IT BACK OVER LS MID MORNING AS THE WINDS BACK TO THE N AND INCREASE BY 18Z. THE 2 AM OBSERVATIONS REFLECT THIS DRY POCKET AS VSBYS HAVE INCREASED TO 8SM AT ASX AND 4SM AT IWD. IN ADDITION...THE HURLEY WEB CAM ALSO SHOWS NON-RESTRICTED VSBYS WITH NO SNOWFALL AT THIS HOUR. AS LONG AS THIS DRY LAYER DOES NOT INTRUDE ANY FURTHER AND RETREATS TO THE NW AS THE MODELS SUGGEST...THE LES SHOWERS SHOULD QUICKLY COMMENCE AFTER SUNRISE. ATTM...WILL KEEP LES WARNING AS IS WITH SLIGHTLY LOWER SN TOTALS DUE TO LATER START. DAY SHIFT WILL NEED TO MONITOR. ARCTIC HIGH PRESSURE WILL DOMINATE THIS AFTERNOON THROUGH TUESDAY. THE HIGH PRESSURE WILL BRING CLEARING SKIES WITH LIGHT WINDS OVERNIGHT. TONIGHT WILL LIKELY BE THE COLDEST OF YET...WITH THE MID 20S BELOW ZERO ACROSS THE IRON RANGE AND ARROWHEAD...AND EVEN SOME FAVORED LOCATIONS AS LOW AS THE 40S BELOW. GRANING && POINT TEMPS/POPS... DLH 7 -17 5 -3 / 20 10 0 10 INL -6 -26 1 -12 / 0 0 0 10 BRD 4 -16 8 -2 / 10 0 0 10 HYR 15 -9 7 -5 / 80 10 0 10 ASX 15 -2 7 0 / 100 40 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND-BAYFIELD-IRON. LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST TUESDAY FOR LSZ121-LSZ146- LSZ147-LSZ148. $$ LILES mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 429 AM CST MON JAN 15 2007 .UPDATE... NO SNOWFALL SPOTTERS HAVE REPORTED OVERNIGHT. HOWEVER...CALLS TO COUNTY LAW ENFORCEMENT HAVE INFORMED ME THAT NEW SNOWFALL OF 2 TO 4 INCHES FELL OVERNIGHT ACROSS WASHBURN...SAWYER AND PRICE COUNTIES. SINCE PINE...DOUGLAS AND BURNETT COUNTIES ALL REPORTED AROUND AN INCH OVERNIGHT...AND THE MAIN FORCING AND STRONGER RADAR RETURNS HAVE ALL PROCEEDED TO THE EAST..CANCELLED THE SN ADVISORY FOR THESE COUNTIES. DOUGLAS COUNTY MAY SEE SOME ACCUMULATION YET DUE TO LAKE EFFECT...WITH UP TO 2 INCHES OF ADDITIONAL ACCUMULATION NEAR LAKE SUPERIOR. && .PREV DISCUSSION... /ISSUED 314 AM CST MON JAN 15 2007/ DISCUSSION... SYNOPTIC SNOW CONTINUES TO TRACK NE ACROSS NRN WISCONSIN WHILE LES SNOW IS FOUND ALONG THE SNOW BELT REGION OF THE SOUTH SHORE. FIRST FCST FOCUS ON TIMING THE BACK EDGE OF THE SNOW...AS WELL AS TOTAL SN AMOUNTS. NO SIG CHANGES TO FCST. PREVIOUS FCST IN GOOD SHAPE WITH LIKELY/DEF POPS ACROSS WI ZONES WHERE VARIOUS HEADLINES ARE IN EFFECT. THE GFS/NAM AGREE THAT THE FORCING ASSOCIATED WITH THE SYNOPTIC SN WILL MOVE EAST AND DIMINISH OVER THE ERN FA THROUGH THIS MORNING...TAPERING OFF FROM WEST TO EAST THIS AFTERNOON. WILL KEEP HEADLINE TIMING AS IS. THE GREATEST SNOWFALL AMOUNTS AWAY FROM LAKE SUPERIOR WILL BE ACROSS THE FAR SE ZONES /SAWYER AND PRICE COUNTIES/. SECOND FCST DIFFICULTY...LES TODAY. CURRENT SFC OBSERVATIONS AND LOCAL WEB CAMS SHOW THAT THE LES HAS WEAKENED. ALTHOUGH THERE ARE LIGHT RADAR RETURNS...AND THE COLD AIR AND TRAJECTORIES ARE IN PLACE...CIGS ARE INCREASING ALONG THE SOUTH SHORE. THE 08Z MSAS AND NAM12 ANALYSIS ARE PICKING UP ON A VERY TIGHT LW LVL RH GRADIENT SITTING PARALLEL AND JUST TO THE NORTH OF THE SOUTH SHORE OF LS. THIS ARCTIC DRY-LINE IS DEPICTED IN BOTH THE 1000-850 MB AND 925-850 MB RH FIELDS...WHERE VALUES OF 35-40 PERCENT ARE FOUND NORTH OF THE THE BOUNDARY ALONG THE NORTH SHORE...AND OVER 80 PERCENT RH JUST INLAND IN NW WIS. THE NAM/RUC BRING THIS DRY AIR OVER THE WRN TIP OF LS AND INTO THE FAR NW CORNER OF WIS THROUGH 12Z...THEN RETREAT IT BACK OVER LS MID MORNING AS THE WINDS BACK TO THE N AND INCREASE BY 18Z. THE 2 AM OBSERVATIONS REFLECT THIS DRY POCKET AS VSBYS HAVE INCREASED TO 8SM AT ASX AND 4SM AT IWD. IN ADDITION...THE HURLEY WEB CAM ALSO SHOWS NON-RESTRICTED VSBYS WITH NO SNOWFALL AT THIS HOUR. AS LONG AS THIS DRY LAYER DOES NOT INTRUDE ANY FURTHER AND RETREATS TO THE NW AS THE MODELS SUGGEST...THE LES SHOWERS SHOULD QUICKLY COMMENCE AFTER SUNRISE. ATTM...WILL KEEP LES WARNING AS IS WITH SLIGHTLY LOWER SN TOTALS DUE TO LATER START. DAY SHIFT WILL NEED TO MONITOR. ARCTIC HIGH PRESSURE WILL DOMINATE THIS AFTERNOON THROUGH TUESDAY. THE HIGH PRESSURE WILL BRING CLEARING SKIES WITH LIGHT WINDS OVERNIGHT. TONIGHT WILL LIKELY BE THE COLDEST OF YET...WITH THE MID 20S BELOW ZERO ACROSS THE IRON RANGE AND ARROWHEAD...AND EVEN SOME FAVORED LOCATIONS AS LOW AS THE 40S BELOW. && POINT TEMPS/POPS... DLH 7 -17 5 -3 / 20 10 0 10 INL -5 -26 1 -12 / 0 0 0 10 BRD 4 -16 8 -2 / 10 0 0 10 HYR 11 -9 7 -5 / 80 10 0 10 ASX 13 -2 7 0 / 100 40 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...SNOW ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR PRICE-SAWYER- WASHBURN. LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND-BAYFIELD-IRON. LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST TUESDAY FOR LSZ121-LSZ146- LSZ147-LSZ148. $$ GRANING mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 314 AM CST MON JAN 15 2007 .DISCUSSION... SYNOPTIC SNOW CONTINUES TO TRACK NE ACROSS NRN WISCONSIN WHILE LES SNOW IS FOUND ALONG THE SNOW BELT REGION OF THE SOUTH SHORE. FIRST FCST FOCUS ON TIMING THE BACK EDGE OF THE SNOW...AS WELL AS TOTAL SN AMOUNTS. NO SIG CHANGES TO FCST. PREVIOUS FCST IN GOOD SHAPE WITH LIKELY/DEF POPS ACROSS WI ZONES WHERE VARIOUS HEADLINES ARE IN EFFECT. THE GFS/NAM AGREE THAT THE FORCING ASSOCIATED WITH THE SYNOPTIC SN WILL MOVE EAST AND DIMINISH OVER THE ERN FA THROUGH THIS MORNING...TAPERING OFF FROM WEST TO EAST THIS AFTERNOON. WILL KEEP HEADLINE TIMING AS IS. THE GREATEST SNOWFALL AMOUNTS AWAY FROM LAKE SUPERIOR WILL BE ACROSS THE FAR SE ZONES /SAWYER AND PRICE COUNTIES/. AS OF 2 AM...PRICE COUNTY SHERIFF REPORTED 4 INCHES IN PHILLIPS AND 2 INCHES IN PARK FALLS. NOT ANTICIPATING AN UPGRADE FOR THESE COUNTIES...BUT LOCATIONS IN FAR SRN PORTIONS OF THESE COUNTIES WILL SEE SN TOTALS UP TO 6 INCHES...WITH POSSIBLE LOCALIZED HIGHER AMOUNTS ALONG AND SOUTH OF HWY 8 NEAR PRENTICE. SECOND FCST DIFFICULTY...LES TODAY. CURRENT SFC OBSERVATIONS AND LOCAL WEB CAMS SHOW THAT THE LES HAS WEAKENED. ALTHOUGH THERE ARE LIGHT RADAR RETURNS...AND THE COLD AIR AND TRAJECTORIES ARE IN PLACE...CIGS ARE INCREASING ALONG THE SOUTH SHORE. THE 08Z MSAS AND NAM12 ANALYSIS ARE PICKING UP ON A VERY TIGHT LW LVL RH GRADIENT SITTING PARALLEL AND JUST TO THE NORTH OF THE SOUTH SHORE OF LS. THIS ARCTIC DRY-LINE IS DEPICTED IN BOTH THE 1000-850 MB AND 925-850 MB RH FIELDS...WHERE VALUES OF 35-40 PERCENT ARE FOUND NORTH OF THE THE BOUNDARY ALONG THE NORTH SHORE...AND OVER 80 PERCENT RH JUST INLAND IN NW WIS. THE NAM/RUC BRING THIS DRY AIR OVER THE WRN TIP OF LS AND INTO THE FAR NW CORNER OF WIS THROUGH 12Z...THEN RETREAT IT BACK OVER LS MID MORNING AS THE WINDS BACK TO THE N AND INCREASE BY 18Z. THE 2 AM OBSERVATIONS REFLECT THIS DRY POCKET AS VSBYS HAVE INCREASED TO 8SM AT ASX AND 4SM AT IWD. IN ADDITION...THE HURLEY WEB CAM ALSO SHOWS NON-RESTRICTED VSBYS WITH NO SNOWFALL AT THIS HOUR. AS LONG AS THIS DRY LAYER DOES NOT INTRUDE ANY FURTHER AND RETREATS TO THE NW AS THE MODELS SUGGEST...THE LES SHOWERS SHOULD QUICKLY COMMENCE AFTER SUNRISE. ATTM...WILL KEEP LES WARNING AS IS WITH SLIGHTLY LOWER SN TOTALS DUE TO LATER START. DAY SHIFT WILL NEED TO MONITOR. ARCTIC HIGH PRESSURE WILL DOMINATE THIS AFTERNOON THROUGH TUESDAY. THE HIGH PRESSURE WILL BRING CLEARING SKIES WITH LIGHT WINDS OVERNIGHT. TONIGHT WILL LIKELY BE THE COLDEST OF YET...WITH THE MID 20S BELOW ZERO ACROSS THE IRON RANGE AND ARROWHEAD...AND EVEN SOME FAVORED LOCATIONS AS LOW AS THE 40S BELOW. && POINT TEMPS/POPS... DLH 7 -17 5 -7 / 40 10 10 10 INL -5 -26 1 -14 / 0 0 0 10 BRD 4 -16 8 -4 / 10 0 0 10 HYR 11 -10 7 -7 / 80 20 10 10 ASX 12 -5 7 -2 / 90 40 30 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...SNOW ADVISORY UNTIL NOON CST TODAY FOR PINE. WI...SNOW ADVISORY UNTIL NOON CST TODAY FOR BURNETT. SNOW ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR PRICE-SAWYER- WASHBURN. LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND-BAYFIELD-IRON. LAKE EFFECT SNOW ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR DOUGLAS. LS...SMALL CRAFT ADVISORY UNTIL 10 AM CST TUESDAY FOR LSZ121-LSZ146- LSZ147-LSZ148. $$ GRANING mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 912 PM CST MON JAN 15 2007 .UPDATE... FIRST WAVE OF STEADY LIGHT RAIN DEPARTING SERN MS LEAVING SOME LIGHT DRIZZLE AND PATCHES OF LIGHT RAIN ACROSS MUCH OF THE CWFA THIS EVENING. UPSTREAM PRECIPITATION SHIELD OF SLEET MIXED WITH RAIN OR FREEZING RAIN ALONG THE SABINE RIVER VALLEY HEADING ENE AND SHOULD PRODUCE SOME PATCHY SLEET/MIXED WITH LIGHT RAIN FOR OUR DELTA COUNTIES BEFORE MIDNIGHT. SURFACE TEMPERATURES REMAIN IN THE UPPER 30S OR HIGHER ACROSS NE LA...SE AR AND THE DELTA AND THESE SHOULD DROP TO MIDDLE 30S AS THE PRECIPITATION MOVES IN. 00Z MODEL RUNS OF RUC/NAM12 NOT ACKNOWLEDGING THE EXTENT OF THE PRECIPITATION SHIELD AS IT MOVES TOWARD THE SLIGHTLY WARMER AIRMASS E OF THE MS RIVER. GROUND TEMPERATURES STILL QUITE WARM AND DO NOT EXPECT ANY SIGNIFICANT IMPACT ISSUES WITH MUCH DRIER LAYER OF AIR IN THE 750-900MB LAYER WORKING IN UNDER THE SATURATED LAYERS ABOVE AND SERVING TO EVAPORATE MOST OF THE FALLING HYDROMETEORS. UPDATED GRAPHICS AND GRIDS ALREADY SENT WITH ZONE PACKAGE TO FOLLOW SHORTLY. && .AVIATION... MOSTLY MVFR CEILINGS 1-2K FEET SHOULD PERSIST OVERNIGHT WITH LOCAL IFR NEAR PATCHY MIXED PRECIPITATION THROUGH EARLY TUESDAY BEFORE IMPROVING TO VFR FROM NW TO SE DURING THE MIDDAY HOURS. EXPECT NNW SURFACE WINDS OF 12-16KTS NOT LETTING UP UNTIL TUESDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 33 40 28 47 / 50 20 12 20 MERIDIAN 36 41 28 47 / 50 23 12 14 VICKSBURG 32 40 29 44 / 50 20 13 24 HATTIESBURG 40 43 31 50 / 50 40 37 14 NATCHEZ 33 38 30 43 / 50 21 37 32 GREENVILLE 31 39 28 42 / 20 9 10 14 GREENWOOD 31 39 27 45 / 29 8 10 13 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 40 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 245 PM CST MON JAN 15 2007 THREE LAYERED STORM WHICH CREATED HAVOC ACROSS MISSOURI THROUGH THE WEEKEND IS NOW WELL TO THE EAST. THE LAST HURRAH FROM THIS SYSTEM IS A NARROW BAND OF LIGHT SNOW WHICH EXTENDS FROM WISCONSIN SOUTH THROUGH NORTHERN ILLINOIS INTO NORTHEAST AND EAST CENTRAL MISSOURI. TEMPERATURES HAVE FALLEN SLOWLY THROUGH THE DAY AND AT FORECAST TIME WILL START IN THE MIDDLE TO UPPER 20S IN ILLINOIS DOWN TO THE MIDDLE TEENS ACROSS CENTRAL MISSOURI. MODIFIED ARCTIC AIR WILL SETTLE DOWN ACROSS THE BISTATE AREA DROPPING OVERNIGHT LOWS TO 5 TO 10 ABOVE NORTHWEST WITH WIND CHILL VALUES 0 TO 10 BELOW THERE. THE EASTERN COUNTIES WON`T GET AS COLD BECAUSE THE CLOUDS WILL HANG IN LONGER. WINDS WILL SETTLE TO 10 TO 15 MPH THROUGH THE NIGHT AND THEN DIE OUT TOMORROW AND TOMORROW NIGHT AS THE HIGH PRESSURE RIDGE LIES OVERHEAD. SOME WARMING IF YOU CAN CALL IT THAT IS ANTICIPATED FOR WEDNESDAY WITH HIGHS IN THE 30S. THE NEXT WEATHER SYSTEM IS FROM THE TAIL OF THE TROUGH THAT GAVE US THIS WEEKEND WEATHER. IT GOT CUT OFF OVER THE SOUTHERN ROCKIES BUT GETS KICKED EAST INTO THE PLAINS BY ANOTHER SHORT WAVE THAT DROPS INTO ITS PLACE. THE AIR WILL BE TOO DRY AND NOTHING OF CONSEQUENCE IS ANTICIPATED WITH IT. OF INTEREST HOWEVER IS THE WEEKEND OUTLOOK. SURROUNDING OFFICES DID NOT WANT TO PUT PRECIPITATION IN UNTIL MONDAY. HOWEVER THE EUROPEAN MODEL HAS BEEN DOING PRETTY WELL OF LATE IN THE MEDIUM RANGE SYNOPTIC PATTERN AND IT HAS A PRETTY DECENT CHUNK OF ENERGY MOVING OUT OF THE ROCKIES INTO THE CENTRAL PLAINS AND PRECIPITATION WILL PROBABLY BREAK OUT FOR SUNDAY INTO MONDAY ACROSS OUR FORECAST AREA. THE EUROPEAN WOULD POINT TO MIXED PRECIPITATION...RAIN SOUTH... MIXED CENTRAL AND SNOW TO MIXED NORTH. WE WILL WAIT TO TAKE A CLOSER LOOK AT IT TOMORROW AND SEE IF THE MODELS CONTINUE TO BRING IT ALONG. IN THE LONGER RANGE IT APPEARS ANOTHER COLD FRONT WILL DRIFT SOUTHEAST REINFORCING THE COOL AIR FOR FRIDAY INTO SATURDAY. PEDIGO && .DISCUSSION... CLASSIC COMMA PCPN STRUCTURE ON RADAR WITH SNOW OVR IA IN THE COMMA HEAD AND A TRAILING BAND OF RAIN ACRS THE SRN AND ERN PTN OF THE CWA IN THE WRM CONVEYOR BELT. PATCHY DRIZZLE OR FREEZING DRIZZLE IS BEING REPORTED ACRS THE NRN AND WRN PTN OF THE CWA...N AND W OF STL...WITH A FEW RPTS OF LGT SLEET AS WELL. MAY STILL HAVE SOME LGT RAIN OVR THE EXTREME SRN AND ERN PTN OF THE CWA ARND 12Z MON AS BOTH NAM AND GFS MDLS STILL DEPICT SOME UPR LVL DIVERGENCE S AND E OF STL ARND 12Z MON AHD OF POSITIVELY TILTED UPR TROF EXTDG FM THE NRN PLAINS SW THRU THE SRN RCKYS. MOST OF THE MEASUREABLE PCPN SHOULD END SHORTLY AFTER 12Z MON THOUGH AS VORT MAX DEPICTED BY LATEST RUC ANLYS OVR W CNTRL MO MOVES NE OF THE CWA LTR THIS MRNG AND THE MOISTURE PROFILE BCMS SHALLOW AFTER 12Z MON AS DISPLAYED ON MDL TIME HGT SECTIONS OF RH. NOT MUCH FORCING FOR UPWARD VERTICAL MOTION BY LT MRNG AND AFTN WITH STG 850 MB CAA BHND 850 MB TROF AND SUBSIDENCE INCRSG WITH STG ARCTIC SFC RDG BLDG SEWD INTO MO BHND SFC LOW AND ATTENDANT CDFNT. MAY STILL SEE SOME PATCHY FREEZING DRIZZLE OR FLURRIES FM COU TO UIN AND PATCHY DRIZZLE CHANGING TO PATCHY FREEZING DRIZZLE AND FLURRIES IN STL AND FAM LT THIS MRNG AND THIS AFTN WITH CYCLONIC MID-UPR LVL FLOW AHD OF THE POSITIVELY TILTED TROF AND A SHALOW MOISTURE PROFILE FM THE SFC TO ARND 850 MB. TEMPERATURES WILL LIKELY SLOWLY FALL DURING THE DAY WITH STG LOW LVL CAA COMBINED WITH A STRATUS OVC SKY ALL DAY. SHOULD HAVE RELATIVELY STG NWLY SFC WNDS TDA DUE TO A TIGHT SFC PRESSURE GRADIENT BTWN SFC LOW MOVG NEWD THRU THE OH VLY REGION AND STG SFC RDG BLDG SEWD THRU THE PLAINS. COLD TEMPERATURES EXPECTED TGT WITH CONTD NWLY LOW LVL WNDS AND CAA. MDLS FCSTG 850 MB TEMPS TO FALL TO ARND -12 TO -15 DGRS C BY 06Z TUE AND SFC DWPTS FALLING TO ARND 10 TO 15 DGRS F BY LT TGT. SHOULD FINALLY SEE SUNSHINE ON TUE WITH MOS GUIDANCE INDICATING DCRSG CLOUDINESS LT MON NGT AND MDL RH FCSTS SHOWING DCRSG LOW LVL RH ON TUE. TEMPERATURES SHOULD STILL REMAIN BLW FREEZING ON TUE DESPITE PLENTY OF SUNSHINE DURING THE AFTN WITH THE STG ARCTIC SFC HI CNTRD OVR THE PLAINS. ANOTHER COLD NGT ON TUE NGT WITH GOOD RADIATIONAL COOLING DUE TO THE SFC RDG OVR THE CWA BRINGING A CLR SKY...LGT SFC WNDS AND SFC DWPTS ONLY IN THE SINGLE DIGITS. TEMPERATURES SHOULD GET ABV THE FREEZING MARK ON WED WITH RISING MID-UPR LVL HGTS AND A RETURN SLY LOW LVL FLOW BGNG ON THE WEST SIDE OF SFC/850 MB RDG. GKS && .AVIATION... FOR THE 18Z TAFS... CEILINGS TO CONTINUE TO RISE THIS AFTERNOON TO MVFR CATEGORY EVEN WITH BAND OF SNOW THAT WILL MOVE ACROSS THE CWA FROM WEST TO EAST. HAVE INCLUDED A 4 TO 5 HOUR WINDOW OF SNOW AT ALL THE TAF SITES WITH VISIBILITIES DROPPING TO 2 OR 3 MILES. OTHERWISE...GUSTY WEST/NORTHWEST WINDS WILL CONTINUE THROUGH THE EARLY EVENING BEFORE SLACKING. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1112 AM CST MON JAN 15 2007 .UPDATE... PLAN TO UPDATE FORECAST FOR THIS AFTERNOON TO ACCOUNT FOR BAND OF LIGHT SNOW THAT WILL CROSS CWA FROM WEST TO EAST. CALLS OUT WEST TO KANSAS CITY INDICATE LITTLE IF ANY ACCUMULATION...BUT VISIBILITIES HAVE DROPPED AS LOW AS A MILE AND A HALF WITHIN THIS BAND. OTHERWISE WINDS HAVE INCREASED AS EXPECTED...AND TEMPERATURES CONTINUE TO FALL AS COLD AIR ADVECTION TAKES OVER. CVKING && .DISCUSSION... CLASSIC COMMA PCPN STRUCTURE ON RADAR WITH SNOW OVR IA IN THE COMMA HEAD AND A TRAILING BAND OF RAIN ACRS THE SRN AND ERN PTN OF THE CWA IN THE WRM CONVEYOR BELT. PATCHY DRIZZLE OR FREEZING DRIZZLE IS BEING REPORTED ACRS THE NRN AND WRN PTN OF THE CWA...N AND W OF STL...WITH A FEW RPTS OF LGT SLEET AS WELL. MAY STILL HAVE SOME LGT RAIN OVR THE EXTREME SRN AND ERN PTN OF THE CWA ARND 12Z MON AS BOTH NAM AND GFS MDLS STILL DEPICT SOME UPR LVL DIVERGENCE S AND E OF STL ARND 12Z MON AHD OF POSITIVELY TILTED UPR TROF EXTDG FM THE NRN PLAINS SW THRU THE SRN RCKYS. MOST OF THE MEASUREABLE PCPN SHOULD END SHORTLY AFTER 12Z MON THOUGH AS VORT MAX DEPICTED BY LATEST RUC ANLYS OVR W CNTRL MO MOVES NE OF THE CWA LTR THIS MRNG AND THE MOISTURE PROFILE BCMS SHALLOW AFTER 12Z MON AS DISPLAYED ON MDL TIME HGT SECTIONS OF RH. NOT MUCH FORCING FOR UPWARD VERTICAL MOTION BY LT MRNG AND AFTN WITH STG 850 MB CAA BHND 850 MB TROF AND SUBSIDENCE INCRSG WITH STG ARCTIC SFC RDG BLDG SEWD INTO MO BHND SFC LOW AND ATTENDANT CDFNT. MAY STILL SEE SOME PATCHY FREEZING DRIZZLE OR FLURRIES FM COU TO UIN AND PATCHY DRIZZLE CHANGING TO PATCHY FREEZING DRIZZLE AND FLURRIES IN STL AND FAM LT THIS MRNG AND THIS AFTN WITH CYCLONIC MID-UPR LVL FLOW AHD OF THE POSITIVELY TILTED TROF AND A SHALOW MOISTURE PROFILE FM THE SFC TO ARND 850 MB. TEMPERATURES WILL LIKELY SLOWLY FALL DURING THE DAY WITH STG LOW LVL CAA COMBINED WITH A STRATUS OVC SKY ALL DAY. SHOULD HAVE RELATIVELY STG NWLY SFC WNDS TDA DUE TO A TIGHT SFC PRESSURE GRADIENT BTWN SFC LOW MOVG NEWD THRU THE OH VLY REGION AND STG SFC RDG BLDG SEWD THRU THE PLAINS. COLD TEMPERATURES EXPECTED TGT WITH CONTD NWLY LOW LVL WNDS AND CAA. MDLS FCSTG 850 MB TEMPS TO FALL TO ARND -12 TO -15 DGRS C BY 06Z TUE AND SFC DWPTS FALLING TO ARND 10 TO 15 DGRS F BY LT TGT. SHOULD FINALLY SEE SUNSHINE ON TUE WITH MOS GUIDANCE INDICATING DCRSG CLOUDINESS LT MON NGT AND MDL RH FCSTS SHOWING DCRSG LOW LVL RH ON TUE. TEMPERATURES SHOULD STILL REMAIN BLW FREEZING ON TUE DESPITE PLENTY OF SUNSHINE DURING THE AFTN WITH THE STG ARCTIC SFC HI CNTRD OVR THE PLAINS. ANOTHER COLD NGT ON TUE NGT WITH GOOD RADIATIONAL COOLING DUE TO THE SFC RDG OVR THE CWA BRINGING A CLR SKY...LGT SFC WNDS AND SFC DWPTS ONLY IN THE SINGLE DIGITS. TEMPERATURES SHOULD GET ABV THE FREEZING MARK ON WED WITH RISING MID-UPR LVL HGTS AND A RETURN SLY LOW LVL FLOW BGNG ON THE WEST SIDE OF SFC/850 MB RDG. GKS && .AVIATION... FOR THE 18Z TAFS... CEILINGS TO CONTINUE TO RISE THIS AFTERNOON TO MVFR CATEGORY EVEN WITH BAND OF SNOW THAT WILL MOVE ACROSS THE CWA FROM WEST TO EAST. HAVE INCLUDED A 4 TO 5 HOUR WINDOW OF SNOW AT ALL THE TAF SITES WITH VISIBILITIES DROPPING TO 2 OR 3 MILES. OTHERWISE...GUSTY WEST/NORTHWEST WINDS WILL CONTINUE THROUGH THE EARLY EVENING BEFORE SLACKING. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 550 AM CST MON JAN 15 2007 .DISCUSSION... CLASSIC COMMA PCPN STRUCTURE ON RADAR WITH SNOW OVR IA IN THE COMMA HEAD AND A TRAILING BAND OF RAIN ACRS THE SRN AND ERN PTN OF THE CWA IN THE WRM CONVEYOR BELT. PATCHY DRIZZLE OR FREEZING DRIZZLE IS BEING REPORTED ACRS THE NRN AND WRN PTN OF THE CWA...N AND W OF STL...WITH A FEW RPTS OF LGT SLEET AS WELL. MAY STILL HAVE SOME LGT RAIN OVR THE EXTREME SRN AND ERN PTN OF THE CWA ARND 12Z MON AS BOTH NAM AND GFS MDLS STILL DEPICT SOME UPR LVL DIVERGENCE S AND E OF STL ARND 12Z MON AHD OF POSITIVELY TILTED UPR TROF EXTDG FM THE NRN PLAINS SW THRU THE SRN RCKYS. MOST OF THE MEASUREABLE PCPN SHOULD END SHORTLY AFTER 12Z MON THOUGH AS VORT MAX DEPICTED BY LATEST RUC ANLYS OVR W CNTRL MO MOVES NE OF THE CWA LTR THIS MRNG AND THE MOISTURE PROFILE BCMS SHALLOW AFTER 12Z MON AS DISPLAYED ON MDL TIME HGT SECTIONS OF RH. NOT MUCH FORCING FOR UPWARD VERTICAL MOTION BY LT MRNG AND AFTN WITH STG 850 MB CAA BHND 850 MB TROF AND SUBSIDENCE INCRSG WITH STG ARCTIC SFC RDG BLDG SEWD INTO MO BHND SFC LOW AND ATTENDANT CDFNT. MAY STILL SEE SOME PATCHY FREEZING DRIZZLE OR FLURRIES FM COU TO UIN AND PATCHY DRIZZLE CHANGING TO PATCHY FREEZING DRIZZLE AND FLURRIES IN STL AND FAM LT THIS MRNG AND THIS AFTN WITH CYCLONIC MID-UPR LVL FLOW AHD OF THE POSITIVELY TILTED TROF AND A SHALOW MOISTURE PROFILE FM THE SFC TO ARND 850 MB. TEMPERATURES WILL LIKELY SLOWLY FALL DURING THE DAY WITH STG LOW LVL CAA COMBINED WITH A STRATUS OVC SKY ALL DAY. SHOULD HAVE RELATIVELY STG NWLY SFC WNDS TDA DUE TO A TIGHT SFC PRESSURE GRADIENT BTWN SFC LOW MOVG NEWD THRU THE OH VLY REGION AND STG SFC RDG BLDG SEWD THRU THE PLAINS. COLD TEMPERATURES EXPECTED TGT WITH CONTD NWLY LOW LVL WNDS AND CAA. MDLS FCSTG 850 MB TEMPS TO FALL TO ARND -12 TO -15 DGRS C BY 06Z TUE AND SFC DWPTS FALLING TO ARND 10 TO 15 DGRS F BY LT TGT. SHOULD FINALLY SEE SUNSHINE ON TUE WITH MOS GUIDANCE INDICATING DCRSG CLOUDINESS LT MON NGT AND MDL RH FCSTS SHOWING DCRSG LOW LVL RH ON TUE. TEMPERATURES SHOULD STILL REMAIN BLW FREEZING ON TUE DESPITE PLENTY OF SUNSHINE DURING THE AFTN WITH THE STG ARCTIC SFC HI CNTRD OVR THE PLAINS. ANOTHER COLD NGT ON TUE NGT WITH GOOD RADIATIONAL COOLING DUE TO THE SFC RDG OVR THE CWA BRINGING A CLR SKY...LGT SFC WNDS AND SFC DWPTS ONLY IN THE SINGLE DIGITS. TEMPERATURES SHOULD GET ABV THE FREEZING MARK ON WED WITH RISING MID-UPR LVL HGTS AND A RETURN SLY LOW LVL FLOW BGNG ON THE WEST SIDE OF SFC/850 MB RDG. GKS && .AVIATION... FOR THE 12Z TAFS... IFR/LIFR CIGS COVERED THE REGION THIS MORNING WITH MVFR CIGS EXTENDING WELL BACK INTO THE UPR MS VLY AND EASTERN KANSAS. SPOTTY PRECIPITATION ALSO BEING REPORTED AND SHOWING UP ON REGIONAL RADARS. WE STAY IN THE CLOUDS TODAY AND TONIGHT IN THE WAKE OF THE LOW PRESSURE SYSTEM NOW ACROSS THE OH VALLEY. NW WINDS WILL INCREASE BY MIDDAY AND STAY GUSTY UNTIL EARLY EVENING...THEN WILL DIMINISH SOME AS THE GRADIENT RELAXES TONIGHT. ANTICIPATING CIGS PREDOMINATELY IN THE IFR CATEGORY THIS MORNING THEN GRADUALLY INCREASING THROUGH THE MVFR RANGE THIS AFTERNOON AND EVENING. THE THREAT OF FLURRIES OR DRIZZLE IS LIKELY TO PERSIST INTO THE AFTERNOON BUT DON`T HAVE ENOUGH CONFIDENCE TO INCLUDE IT IN THE TAFS MUCH BEYOND THE FIRST 4 HOURS. GLASS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1138 PM CST SAT JAN 13 2007 .UPDATE... HAVE UPDATED FORECAST TO REFLECT THE DECREASING CHC OF MEASURABLE PRECIP OVER NWRN PART OF THE CWA OVERNIGHT. RADAR SHOWS THAT PRECIP IS SOUTH OF A COU-PPQ LINE CURRENTLY...AND FORCING FIELDS FROM THE MODELS SUGGEST LACK OF LARGE SCALE ASCENT...SO HAVE LOWERED POPS TO THE CHC CATEGORY HERE AND INCLUDED MENTION OF FZDZ. FARTHER SOUTH...STILL SEE DECENT AMOUNT LOW LEVEL CONVERGENCE AND TRANSPORT ASSOCIATED WITH LOW LEVEL JET TO KEEP CATEGORICAL POPS FOR RAIN OR FREEZING RAIN. 00Z RUNS OF THE GFS/NAM ARE DISAGREEING ON TIMING AND PLACEMENT OF QPF TOMORROW/TOMORROW NIGHT ASSOCIATED WITH THE THIRD SHORTWAVE INCREASING UNCERTAINTY IN FORECAST. SURFACE TEMPERATURES WILL BE PROBLEMATIC AS NAM/GFS/21Z SREF 2M TEMPS AND NAM MOS GUIDANCE GO ABOVE FREEZING OVER E CNTRL AND SERN MO/SWRN AND S CNTRL IL TOMORROW/ TOMORROW EVENING. THE RUC40 TEMPS ARE VERIFYING BETTER THAN THESE...AND HAVE SLIGHTLY COOLER TEMPS THAN THESE AT ITS 12 HOUR FORECAST. THINK GOING FORECAST HANDLES THIS OK...AND WARNINGS STILL LOOK GOOD FOR NOW. BRITT && .DISCUSSION... SECOND IN A SERIES OF DISTURBANCES IS HEADED FOR THE AREA. THE PRECIPITATION FROM THIS WILL BE LIGHT BUT WITH TEMPERATURES BELOW FREEZING IN MOST OF THE AREA IT WILL ADD AGGRAVITING CONDITIONS TO THE AREA FOR THE NIGHT. TEMPS HELD PRETTY STEADY TODAY...RISING SLIGHTLY OVER SOUTHERN ILLINOIS AND HOLDING STEADY IN THE COLD AIR ACROSS MISSOURI. OVER A 100,000 PEOPLE ARE STILL WITHOUT POWER ACCORDING TO AMEREN ELECTRIC COMPANY...PRIMARILY JUST WEST TO NORTH OF ST LOUIS AND CENTERED IN ST. CHARLES COUNTY. ICE STORM WARNING CONTINUES ACROSS MUCH OF THE REGION THROUGH SUNDAY NIGHT. THE MAIN EVENT IS GOING TO DEVELOP NORTHEAST ACROSS THE AREA SUNDAY AND SUNDAY EVENING. LOOK FOR SIGNIFICANT ICING CENTERED FROM JEFFERSON CITY NORTHEAST TO 60 MILES NORTH OF ST LOUIS. THIS WILL MORE OR LESS PARALLEL THE FIRST WAVE OF ICING WHICH OCCURED YESTERDAY. THIS WILL BRING ICING TOTALS IN SOME AREAS TO AN INCH OR SO WHICH WILL CREATE HAVOC WITH TREES AND PROPERTY. AS THE TROF APPROACHES A SURFACE LOW IS FORECAST TO FORM OVER EASTERN ARKANSAS TOMORROW AFTERNOON AND DEEPEN NORTHEAST ALONG THE OHIO RIVER BY MONDAY MORNING. MEANWHILE THE CANADIAN HIGH OVER THE PLAINS WILL STRENGTHEN AND CREATE NORTHWEST SURFACE WINDS OF 15 TO 25 MPH ON MONDAY. THIS WILL BE THE REAL KILLER FOR TREE DAMAGE AND POWER OUTAGES. IN ADDITION TEMPERATURES WILL BE FALLING SLOWLY THROUGH THE DAY AND THEN TUMBLE TO SINGLE DIGITS MONDAY NIGHT IN THE ICE COVERED AREA. WIND CHILLS WILL FALL BELOW ZERO CREATING DANGEROUS CONDITIONS FOR THOSE WITHOUT POWER. FAR NORTHERN COUNTIES WILL HAVE SLEET AND SNOW MIXED AND REACH 1 TO 4 INCHES ACROSS THAT AREA. FINALLY...THE RAIN HAS BEGUN TO IMPACT SOME OF THE RIVERS AND STREAMS ACROSS SRN MO. WE RECEIVED 1.5 TO 2.5 INCHES OF RAIN ACROSS THAT AREA AND HEAVY AMOUNTW WILL RE-OCCUR SUNDAY AND SUNDAY NIGHT. THOSE SAME AREAS WILL LIKELY RECEIVE 1 TO 3 INCHES. THEREFORE WE ARE KEEPING THE FLOOD WATCH IN EFFECT FOR SEVERAL SOUTHERN COUNTIES THROUGH SUNDAY NIGHT. PEDIGO && .AVIATION... FOR THE 06Z TAFS...IFR CONDITIONS EXPECTED TO PREVAIL...WITH FEW INTERRUPTIONS...THRU THE VALID TAF PERIOD. LOOK FOR A EPISODES OF FZDZ THROUGH MIDDAY SUNDAY BEFORE NEXT SHOT OF PCPN ARRIVES. WILL BE INITIALLY FZRA MOST LOCATIONS...BUT AS COLDER AND DEEPER AIR FILLS IN OVER THE NWRN FA AND BUILDS SEWD...LOOK FOR PL AND EVENTUALLY SN TO APPEAR...HOWEVER FOR ALL AREAS EXCEPT KUIN...THIS WILL BE JUST BEFORE PCPN ENDS. WINDS WILL REMAIN NLY BETWEEN 5 AND 10 KTS. TES && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR CRAWFORD-IRON-MADISON- REYNOLDS-ST. FRANCOIS-STE. GENEVIEVE-WASHINGTON. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR AUDRAIN-BOONE- CALLAWAY-COLE-CRAWFORD-FRANKLIN-GASCONADE-JEFFERSON-KNOX- LEWIS-LINCOLN-MARION-MONITEAU-MONROE-MONTGOMERY-OSAGE-PIKE- RALLS-SHELBY-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-WARREN- WASHINGTON. IL...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR RANDOLPH IL-WASHINGTON IL. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR ADAMS IL-BOND IL- BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-MONROE IL-MONTGOMERY IL-PIKE IL- ST. CLAIR IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORTH PLATTE NE 805 PM CST MON JAN 15 2007 .UPDATE... AT 01Z SURFACE HIGH PRESSURE WAS ELONGATED OVER THE EASTERN PLAINS RIDGING SOUTH...WITH HIGH CENTER NOW ACROSS NORTHEAST NEBRASKA. TEMPERATURES DROPPING TO BELOW ZERO FOR AREAS EAST OF A LINE FROM ANW TO LXN WITH RUC A LITTLE FAST PUSHING THE COLDER AIR EAST THIS EVENING THAN OBSERVED. TEMPERATURES LOWERED ACROSS THE NORTH CENTRAL A CATEGORY THAT MAY STILL BE A CONSERVATIVE NUMBER TONIGHT. && .PREV DISCUSSION... /ISSUED 233 PM CST MON JAN 15 2007/ ..FORECAST CHALLENGE IS TEMPERATURES... SYNOPSIS...COLD AIR REMAINS ENTRENCHED ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON. TEMPERATURES HAVE STRUGGLED TO REACH THE LOWER TEENS...WITH LOCATIONS IN NERN NEBRASKA...REMAINING IN THE SINGLE DIGITS. ARCTIC HIGH PRESSURE REMAINS ANCHORED OVER THE NORTHERN PLAINS ATTM AND WILL DRIFT SWD INTO NEBRASKA OVERNIGHT. A BROAD LONGWAVE TROF HIGHLIGHTS THE UPPR AIR PATTERN OVER NEARLY ALL OF THE CONUS THIS MORNING. THE EXCEPTION IS OVER THE FAR SERN STATES AND RIDGING BUILDING INTO THE ERN PACIFIC. NEAR TERM (TONIGHT THROUGH WEDNESDAY)...MAIN CHALLENGES IN THE NEAR TERM ARE TEMPERATURES AND TIMING OF MIDWEEK WAVE AND ASSOC FROPA WEDS/WEDS NIGHT. FOR TONIGHT...PRESSING QUESTION IS HOW LOW WILL TEMPS GO? MIN TEMPS THIS MORNING BOTTOMED OUT AT -12 AND -10 FOR LBF AND VTN RESPECTIVELY...AND THAT WAS WITH A 10MPH WIND. LATEST NAM FCST BUILDS A 1040 MB HIGH OVER THE ERN HALF OF NEBR BY 12Z TUESDAY WITH CLEAR SKIES AND LIGHT WINDS. WILL FCST PERSISTENCE FOR TOMORROW MORNING...WHICH IS WELL BELOW THE LOWEST GUIDANCE (MAV) NUMBERS FOR TOMORROW. WOULDN`T BE SURPRISED IF LOWS BOTTOM OUT FURTHER THAN WHAT WE HAVE GOING IN THE FCST...BUT REGARDLESS...A GOOD PLACE TO START. TEMPS WILL BE SLOW TO WARM ON TUESDAY...AS SRLY FLOW RECYCLES ARCTIC AIR ON THE BACK SIDE OF THE EXITING HIGH...RESULTING IN TEENS AND 20S FOR HIGHS. HIGH TEMPS WILL WARM INTO THE 20S AND LWR 30S FOR WEDNESDAY...AS WEAK RIDGING SETS IN AHEAD OF THE NEXT APPG WAVE. H85 TEMPS INCREASE TO NEAR 0C BY WEDNESDAY AFTERNOON. WITH MIXING...30S AND LWR 40S WOULD BE EXPECTED...HOWEVER SNOW COVER WILL PUT THE KABOSH ON THIS. BY WEDNESDAY NIGHT...THE BEFORE MENTIONED UPPER LEVEL DISTURBANCE WILL LIFT ACROSS THE CENTRAL PLAINS...DRIVING A COLD FRONT INTO WESTERN AND NORTH CENTRAL NEBRASKA OVERNIGHT. MOISTURE AHEAD OF THE TROF SHUNTED EAST OF THE CWA...SO DRY FCST CONTINUES. ONLY OUTSIDE CHANCE OF PRECIP WILL LIE WITH THE FROPA. WILL INCREASE CLOUDINESS AND LEAVE DRY FOR NOW. LONG TERM (THURSDAY THROUGH MONDAY)...LONG TERM MODEL SOLNS FAIRLY CONSISTENT THIS MORNING WITH DEVELOPING A REX BLOCK ACROSS THE EASTERN PACIFIC. PATTERN AMPLIFICATION AND DEEPENING OF THE DOWN STREAM FLOW ACROSS THE CENTRAL AND EASTERN CONUS BEGINS ON WEDNESDAY NIGHT AND IS AMPLIFIED FURTHER ON THURSDAY AS A TROF SLIDES ACROSS EASTERN CANADA AND THE UPPR GREAT LAKES. THIS WILL OPEN UP THE CWA TO A BACK DOOR INTRUSION OF COLD AIR FOR THURSDAY AND FRIDAY. WITH THE BACK DOOR INTRUSION OF COLD AIR AND PERSISTENT SNOWCOVER...LOWERED FORECAST HIGHS AND LOWS FOR THURSDAY AND FRIDAY. THE BEFORE MENTIONED TROF WILL BEGIN TO SLIDE EAST ON FRIDAY NIGHT INTO SATURDAY...ALLOWING SOME WARMER AIR TO WORK INTO THE CWA FOR THE WEEKEND. TEMPERATURES WILL BE WARMER...HOWEVER KEPT THEM BELOW GUIDANCE AS SNOW COVER EXPECTED TO PERSIST. AM EXPECTING DRY CONDS FOR THE WEEKEND...HOWEVER WILL CONTINUE TO MONITOR A CLOSED SYSTEM TRAVERSING THE DESERT SW LATE IN THE WEEK. SO FAR...THE MODELS LIFT THIS FEATURE ACROSS THE HIGH PLAINS AS AN OPEN WAVE...FOCUSING THE BEST LIFT AND MOISTURE ACROSS THE SRN PLAINS AND NORTH ACROSS THE DAKOTAS. WITH MEX GUIDANCE AND NATL GUIDANCE BLO CLIMO FOR POPS...WILL KEEP THINGS DRY AND MONITOR. AVIATION...UNDER HIGH PRESSURE...MAINLY CLEAR SKIES AND VFR CONDS EXPECTED FOR THE NEXT 24 HOURS. LBF WATCHES/WARNINGS/ADVISORIES...NONE. $$ && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19/CLB ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1220 PM EST MON JAN 15 2007 .UPDATE... GIVEN CRNT MESONET/ASOS TEMPS...WE WILL CANCEL THE WINTER STORM WARNING FOR ALL ZONES WITH XCPTN OF ONEIDA, WHERE TEMPS STILL ARND FREEZING. SOME ISOLD -FZRA STILL PSBL FOR THE NXT HR OR SO ACRS FAR NRN ONONDADA BUT THREAT IS DIMINISHING. COULD SEE A BRIEF PD OF MIXED PCPN BEFORE IT TRANSITIONS TO -SHSN ACRS THE FINGER LAKES LATE TDA OR THIS EVNG, BUT ATTM DON`T XPCT MUCH IN THE WAY OF PRBLMS FOR THE REMAINDER OF THE DAYLIGHT HRS. && .PREV DISCUSSION... /ISSUED 1031 AM EST MON JAN 15 2007/ UPDATE... FOR THE 11 AM UPDATE THE PLAN IS TO LET EXPIRE/CANCEL THE ADVISORY/WARNINGS FOR STEUBEN, SCHUYLER, TOMPKINS, CORTLAND, CHENANGO, OTSEGO, DELAWARE, AND SULLIVAN IN NY AND WAYNE/PIKE IN NE PA. THERE MAY BE SOME ISOLD POCKETS PERSISTING IN THESE AREAS...SPCLY THE WRN CATSKILLS BUT TEMPS CONTINUE THEIR SLOW CLIMB. WILL LEAVE WARNING UP FOR THE NRN COUNTIES BUT WILL PRBLY BE ABLE TO CANCEL THEM THIS AFTN. PREV DISCUSSION... /ISSUED 822 AM EST MON JAN 15 2007/ UPDATE... SFC TEMP ANYLS SHOWS A THERMAL RDG XTNDG FROM THE WYOMING VLY INTO THE SRN TIER OF NY...WITH COLDER TEMPS AOA 32F PERSISTING ACRS THE FINGER LAKES...WRN MOHAWK VLY INTO THE WRN CATSKILLS. WE HAVE RECIEVED A RPT FROM SRN CAYUGA COUNTY WHERE TREE LIMBS WERE COMING DOWN DUE TO THE ICE. WE WILL INCREMENTALLY BEGIN TO TAKE DOWN SOME OF THE ADVISORIES/WARNINGS WHERE TEMPS HAVE RISEN ABV FREEZING. HYDROWISE... WE COULD SEE SOME OF OUR HEADWATER PTS APRCH FS...BUT ATTM FEEL THAT ANY FLOODING CONCERNS WOULD BE FAIRLY MINOR. PREV DISCUSSION... /ISSUED 659 AM EST MON JAN 15 2007/ SHORT TERM /REST OF TODAY/... JUST SENT A REFRESHER BATCH OF ZONES AND STATEMENTS. WARM AIR HAS MADE INTO WYOMING AND LACKAWANNA COUNTIES. MESO OBS STILL SHOW TEMPS CLOSE TO FREEZING AT HIGH ELEVATIONS IN THIS RANGE, BUT CLEARLY THE EVENT SHOULD BE ENDING SOON FOR THIS AREA. AS FORECAST, COLD AIR DAMMING IS SHOWING UP OVER EASTERN ZONES AND SHOULD KEEP ICE ACCUMULATION CONTINUING. CURRENT THINKING IS TEMPS WILL WARM INTO 33F-35F BY 10 AM OVER SO TIER OF NY. COULD TAKE UNTIL EARLY AFTERNOON HOWEVER OVER FINGER LAKES CATSKILLS. NORTHERN ONEIDA MAY NOT EVER GET THAT HIGH, BUT SHOULD SEE A PRECIP TYPE CHANGEOVER TO SNOW WITH THE COLD FRONT LATE AFTERNOON. DJP PREV DISCUSSION... /ISSUED 651 AM EST MON JAN 15 2007/ AVIATION /151200Z-161200Z/... CENTRAL NY SITES HAVE STEADY FZRA WITH MAINLY IFR CIGS AND MVFR VSBYS. AVP THE BEST TO START AND IN GENERAL WITH MVFR CIGS AND VFR TO MVFR VSBYS. CIGS MAY DIP DOWN TO IFR AS HEAVIER RAIN MOVES IN LATER THIS MORNING. SFC LOW TRACKS TO NW BRINGING A WARM FRONT AND IMPROVING CONDITIONS THIS AFTN FOLLOWED BY A COLD FRONT THIS EVENING. NY SITES SHOULD REMAIN THE SAME WITH VSBY AND CIGS EVEN AS FZRA CHANGES TO RA THIS MORNING. CIG AND VSBY IMPROVEMENT WITH WARM FRONT. WINDS SHIFT FROM SE TO SW AND REMAINING AT 5 TO 10 KTS. COLD FRONT WILL BRING ANOTHER WIND SHIFT TO NW. GENERALLY MVFR CONDITIONS LATE TODAY AND OVERNIGHT. SOME SNOW SHOWERS LATE IN PERIOD WITH MUCH COLDER AIR RACING IN FOR SYR...RME...AND ITH. PREV DISCUSSION... /ISSUED 209 AM EST MON JAN 15 2007/ HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NYZ009- 015>018-036-037-046. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1031 AM EST MON JAN 15 2007 .UPDATE... FOR THE 11 AM UPDATE THE PLAN IS TO LET EXPIRE/CANCEL THE ADVISORY/WARNINGS FOR STEUBEN, SCHUYLER, TOMPKINS, CORTLAND, CHENANGO, OTSEGO, DELAWARE, AND SULLIVAN IN NY AND WAYNE/PIKE IN NE PA. THERE MAY BE SOME ISOLD POCKETS PERSISTING IN THESE AREAS...SPCLY THE WRN CATSKILLS BUT TEMPS CONTINUE THEIR SLOW CLIMB. WILL LEAVE WARNING UP FOR THE NRN COUNTIES BUT WILL PRBLY BE ABLE TO CANCEL THEM THIS AFTN. && .PREV DISCUSSION... /ISSUED 822 AM EST MON JAN 15 2007/ UPDATE... SFC TEMP ANYLS SHOWS A THERMAL RDG XTNDG FROM THE WYOMING VLY INTO THE SRN TIER OF NY...WITH COLDER TEMPS AOA 32F PERSISTING ACRS THE FINGER LAKES...WRN MOHAWK VLY INTO THE WRN CATSKILLS. WE HAVE RECIEVED A RPT FROM SRN CAYUGA COUNTY WHERE TREE LIMBS WERE COMING DOWN DUE TO THE ICE. WE WILL INCREMENTALLY BEGIN TO TAKE DOWN SOME OF THE ADVISORIES/WARNINGS WHERE TEMPS HAVE RISEN ABV FREEZING. HYDROWISE... WE COULD SEE SOME OF OUR HEADWATER PTS APRCH FS...BUT ATTM FEEL THAT ANY FLOODING CONCERNS WOULD BE FAIRLY MINOR. PREV DISCUSSION... /ISSUED 659 AM EST MON JAN 15 2007/ SHORT TERM /REST OF TODAY/... JUST SENT A REFRESHER BATCH OF ZONES AND STATEMENTS. WARM AIR HAS MADE INTO WYOMING AND LACKAWANNA COUNTIES. MESO OBS STILL SHOW TEMPS CLOSE TO FREEZING AT HIGH ELEVATIONS IN THIS RANGE, BUT CLEARLY THE EVENT SHOULD BE ENDING SOON FOR THIS AREA. AS FORECAST, COLD AIR DAMMING IS SHOWING UP OVER EASTERN ZONES AND SHOULD KEEP ICE ACCUMULATION CONTINUING. CURRENT THINKING IS TEMPS WILL WARM INTO 33F-35F BY 10 AM OVER SO TIER OF NY. COULD TAKE UNTIL EARLY AFTERNOON HOWEVER OVER FINGER LAKES CATSKILLS. NORTHERN ONEIDA MAY NOT EVER GET THAT HIGH, BUT SHOULD SEE A PRECIP TYPE CHANGEOVER TO SNOW WITH THE COLD FRONT LATE AFTERNOON. DJP PREV DISCUSSION... /ISSUED 651 AM EST MON JAN 15 2007/ AVIATION /151200Z-161200Z/... CENTRAL NY SITES HAVE STEADY FZRA WITH MAINLY IFR CIGS AND MVFR VSBYS. AVP THE BEST TO START AND IN GENERAL WITH MVFR CIGS AND VFR TO MVFR VSBYS. CIGS MAY DIP DOWN TO IFR AS HEAVIER RAIN MOVES IN LATER THIS MORNING. SFC LOW TRACKS TO NW BRINGING A WARM FRONT AND IMPROVING CONDITIONS THIS AFTN FOLLOWED BY A COLD FRONT THIS EVENING. NY SITES SHOULD REMAIN THE SAME WITH VSBY AND CIGS EVEN AS FZRA CHANGES TO RA THIS MORNING. CIG AND VSBY IMPROVEMENT WITH WARM FRONT. WINDS SHIFT FROM SE TO SW AND REMAINING AT 5 TO 10 KTS. COLD FRONT WILL BRING ANOTHER WIND SHIFT TO NW. GENERALLY MVFR CONDITIONS LATE TODAY AND OVERNIGHT. SOME SNOW SHOWERS LATE IN PERIOD WITH MUCH COLDER AIR RACING IN FOR SYR...RME...AND ITH. PREV DISCUSSION... /ISSUED 209 AM EST MON JAN 15 2007/ HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL NOON EST TODAY FOR NYZ022-057-062. WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-023-025-036-037-044>046. PA...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ040-048-072. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 822 AM EST MON JAN 15 2007 .UPDATE... SFC TEMP ANYLS SHOWS A THERMAL RDG XTNDG FROM THE WYOMING VLY INTO THE SRN TIER OF NY...WITH COLDER TEMPS AOA 32F PERSISTING ACRS THE FINGER LAKES...WRN MOHAWK VLY INTO THE WRN CATSKILLS. WE HAVE RECIEVED A RPT FROM SRN CAYUGA COUNTY WHERE TREE LIMBS WERE COMING DOWN DUE TO THE ICE. WE WILL INCREMENTALLY BEGIN TO TAKE DOWN SOME OF THE ADVISORIES/WARNINGS WHERE TEMPS HAVE RISEN ABV FREEZING. HYDROWISE... WE COULD SEE SOME OF OUR HEADWATER PTS APRCH FS...BUT ATTM FEEL THAT ANY FLOODING CONCERNS WOULD BE FAIRLY MINOR. && .PREV DISCUSSION... /ISSUED 659 AM EST MON JAN 15 2007/ SHORT TERM /REST OF TODAY/... JUST SENT A REFRESHER BATCH OF ZONES AND STATEMENTS. WARM AIR HAS MADE INTO WYOMING AND LACKAWANNA COUNTIES. MESO OBS STILL SHOW TEMPS CLOSE TO FREEZING AT HIGH ELEVATIONS IN THIS RANGE, BUT CLEARLY THE EVENT SHOULD BE ENDING SOON FOR THIS AREA. AS FORECAST, COLD AIR DAMMING IS SHOWING UP OVER EASTERN ZONES AND SHOULD KEEP ICE ACCUMULATION CONTINUING. CURRENT THINKING IS TEMPS WILL WARM INTO 33F-35F BY 10 AM OVER SO TIER OF NY. COULD TAKE UNTIL EARLY AFTERNOON HOWEVER OVER FINGER LAKES CATSKILLS. NORTHERN ONEIDA MAY NOT EVER GET THAT HIGH, BUT SHOULD SEE A PRECIP TYPE CHANGEOVER TO SNOW WITH THE COLD FRONT LATE AFTERNOON. DJP PREV DISCUSSION... /ISSUED 651 AM EST MON JAN 15 2007/ AVIATION /151200Z-161200Z/... CENTRAL NY SITES HAVE STEADY FZRA WITH MAINLY IFR CIGS AND MVFR VSBYS. AVP THE BEST TO START AND IN GENERAL WITH MVFR CIGS AND VFR TO MVFR VSBYS. CIGS MAY DIP DOWN TO IFR AS HEAVIER RAIN MOVES IN LATER THIS MORNING. SFC LOW TRACKS TO NW BRINGING A WARM FRONT AND IMPROVING CONDITIONS THIS AFTN FOLLOWED BY A COLD FRONT THIS EVENING. NY SITES SHOULD REMAIN THE SAME WITH VSBY AND CIGS EVEN AS FZRA CHANGES TO RA THIS MORNING. CIG AND VSBY IMPROVEMENT WITH WARM FRONT. WINDS SHIFT FROM SE TO SW AND REMAINING AT 5 TO 10 KTS. COLD FRONT WILL BRING ANOTHER WIND SHIFT TO NW. GENERALLY MVFR CONDITIONS LATE TODAY AND OVERNIGHT. SOME SNOW SHOWERS LATE IN PERIOD WITH MUCH COLDER AIR RACING IN FOR SYR...RME...AND ITH. PREV DISCUSSION... /ISSUED 209 AM EST MON JAN 15 2007/ HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. PA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-048-072. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 659 AM EST MON JAN 15 2007 .SHORT TERM /REST OF TODAY/... JUST SENT A REFRESHER BATCH OF ZONES AND STATEMENTS. WARM AIR HAS MADE INTO WYOMING AND LACKAWANNA COUNTIES. MESO OBS STILL SHOW TEMPS CLOSE TO FREEZING AT HIGH ELEVATIONS IN THIS RANGE, BUT CLEARLY THE EVENT SHOULD BE ENDING SOON FOR THIS AREA. AS FORECAST, COLD AIR DAMMING IS SHOWING UP OVER EASTERN ZONES AND SHOULD KEEP ICE ACCUMULATION CONTINUING. CURRENT THINKING IS TEMPS WILL WARM INTO 33F-35F BY 10 AM OVER SO TIER OF NY. COULD TAKE UNTIL EARLY AFTERNOON HOWEVER OVER FINGER LAKES CATSKILLS. NORTHERN ONEIDA MAY NOT EVER GET THAT HIGH, BUT SHOULD SEE A PRECIP TYPE CHANGEOVER TO SNOW WITH THE COLD FRONT LATE AFTERNOON. DJP && .PREV DISCUSSION... /ISSUED 651 AM EST MON JAN 15 2007/ AVIATION /151200Z-161200Z/... CENTRAL NY SITES HAVE STEADY FZRA WITH MAINLY IFR CIGS AND MVFR VSBYS. AVP THE BEST TO START AND IN GENERAL WITH MVFR CIGS AND VFR TO MVFR VSBYS. CIGS MAY DIP DOWN TO IFR AS HEAVIER RAIN MOVES IN LATER THIS MORNING. SFC LOW TRACKS TO NW BRINGING A WARM FRONT AND IMPROVING CONDITIONS THIS AFTN FOLLOWED BY A COLD FRONT THIS EVENING. NY SITES SHOULD REMAIN THE SAME WITH VSBY AND CIGS EVEN AS FZRA CHANGES TO RA THIS MORNING. CIG AND VSBY IMPROVEMENT WITH WARM FRONT. WINDS SHIFT FROM SE TO SW AND REMAINING AT 5 TO 10 KTS. COLD FRONT WILL BRING ANOTHER WIND SHIFT TO NW. GENERALLY MVFR CONDITIONS LATE TODAY AND OVERNIGHT. SOME SNOW SHOWERS LATE IN PERIOD WITH MUCH COLDER AIR RACING IN FOR SYR...RME...AND ITH. PREV DISCUSSION... /ISSUED 209 AM EST MON JAN 15 2007/ HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. PA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-048-072. && $$ SHORT TERM... ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 651 AM EST MON JAN 15 2007 .AVIATION /151200Z-161200Z/... CENTRAL NY SITES HAVE STEADY FZRA WITH MAINLY IFR CIGS AND MVFR VSBYS. AVP THE BEST TO START AND IN GENERAL WITH MVFR CIGS AND VFR TO MVFR VSBYS. CIGS MAY DIP DOWN TO IFR AS HEAVIER RAIN MOVES IN LATER THIS MORNING. SFC LOW TRACKS TO NW BRINGING A WARM FRONT AND IMPROVING CONDITIONS THIS AFTN FOLLOWED BY A COLD FRONT THIS EVENING. NY SITES SHOULD REMAIN THE SAME WITH VSBY AND CIGS EVEN AS FZRA CHANGES TO RA THIS MORNING. CIG AND VSBY IMPROVEMENT WITH WARM FRONT. WINDS SHIFT FROM SE TO SW AND REMAINING AT 5 TO 10 KTS. COLD FRONT WILL BRING ANOTHER WIND SHIFT TO NW. GENERALLY MVFR CONDITIONS LATE TODAY AND OVERNIGHT. SOME SNOW SHOWERS LATE IN PERIOD WITH MUCH COLDER AIR RACING IN FOR SYR...RME...AND ITH. && .PREV DISCUSSION... /ISSUED 209 AM EST MON JAN 15 2007/ HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. PA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-048-072. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 209 AM EST MON JAN 15 2007 .HYDROLOGY... SOME CONCERN THIS MORNING ABOUT FLOOD POTENTIAL. PRECIP TYPE MIX OF FREEZING RAIN AND RAIN MOST AREAS WITH MORE ICE IN THE NORTH. FORECASTED RAINFALL AMOUNTS AROUND AN INCH. MARFC HEADWATER GUIDANCE SHOWS MONROETON AND SHERBURNE AT 1 AND 1.2 INCHES RESPECTIVELY IN 6 AND ALSO 12 HOURS. OTHER HEADWATER AND FLASH FLOOD GUIDANCE FROM BOTH RFCS HIGHER MOSTLY BETWEEN 1.5 AND 2.5 INCHES. STREAMS AND RIVERS RUNNING UNSEASONABLY HIGH WITH SATURATED OR FROZEN GROUND. WITH AFTN TEMPS INTO 40S ALL BUT FAR N AND E ANY ICE ACCUMULATED THIS MORNING WILL MELT AND RUNOFF. IN THE FAR N AND E THERE WILL BE MORE ICE SO EXPECTED PRECIP TOTALS WILL NOT ALL RUN OFF LIKE SRN TIER NY AND NE PA. AFTER CHAT WITH SURROUNDING OFFICES WILL HOLD OFF ON A FLOOD WATCH ATTM. ANY FLOOD PROBLEMS WILL HOLD OFF UNTIL MIDDAY AND SHOULD BE MINOR AT WORST. WILL CONTINUE TO MONITOR AS ALWAYS. TAC && .PREV DISCUSSION... /ISSUED 125 AM EST MON JAN 15 2007/ SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. AVIATION /06Z-06Z/... STARTING CONDITIONS MOSTLY MVFR TO VFR. EXCEPTION IS BGM WITH IFR VSBY AND LIFR CIG. AS STEADY PRECIP MOVES IN THE NEXT 3 HOURS CONDITIONS WILL DROP TO IFR/LIFR CIGS EVERYWHERE FROM SW TO NE. VSBYS MAY STAY AT MVFR ALL BUT BGM. PRECIP TYPES WILL BE RAIN AT AVP...SNPL AT RME AND MAYBE SYR...AND FZRA ALL OTHERS. WINDS NE TO E AT 5 TO 10 KTS. PRECIP TO CHANGE TO JUST RAIN FROM SW TO NE DURING THE DAY MONDAY AS CIGS RISE SOME TO MVFR AS THE WARM FRONT LIFTS THROUGH IN THE AFTN BRIEFLY. WINDS SHIFT TO S TO SW AT 5 TO 10 KTS. COLD FRONT FROM 23Z TO 02Z WILL SHIFT THE WINDS TO W TO NW AT 5 TO 10 KTS. ALL SITES IMPROVE TO MVFR/VFR CIGS AND VSBYS. STEADY PRECIP ENDS. IF ANYTHING THEN SOME SCT LIGHT SNOW SHOWERS BUT NOT MENTIONED THAT FAR OUT IN TAFS. TAC && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. PA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-048-072. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 125 AM EST MON JAN 15 2007 .SHORT TERM /TODAY/... WE ANTICIPATE AN EARLY ISSUANCE OF THE FORECAST PRODUCTS THIS MORNING TO GET AS MUCH LEAD TIME AS POSSIBLE FOR FLAG UPGRADES. A POTENTIALLY DANGEROUS SITUATION IS SETTING UP FOR THE EASTERN FORECAST AREA. WHILE THE FOCUS HAS RIGHTLY BEEN ON ICE ACCUMULATION OVER THE FINGER LAKES, ONONDAGA, MADISON, AND ONEIDA COUNTIES, NEW MESOSCALE MODEL GUIDANCE IS SUGGESTING SIGNIFICANT ICE ACCUMULATION INTO THE CATSKILLS REGION, AND MAYBE EVEN THE POCONOS. A LARGE POOL OF VERY COLD AIR IS IN PLACE OVER EXTREME NORTHERN NEW YORK AND NEW ENGLAND, INTO QUEBEC PROVINCE. RUC40 AND NAM12 SFC TEMP FIELDS EACH SHOW THIS COLD AIR BLEEDING SOUTHWARD INTO THE CATSKILLS OVER THE NEXT SEVERAL HOURS, AND REMAINING FIXED FOR A GOOD PORTION OF TODAY. THIS IS CONSISTENT WITH CLIMATOLOGY...WE HAVE SEEN THIS MANY TIMES. IN THE MEANTIME MOISTURE IS STREAMING NORTHWARD AS ANTICIPATED. GIVEN THE STRONG TEMP GRADIENT FORECAST OVER THE EASTERN FA, PLUS THE ADDED TERRAIN LIFT, THINK THIS AREA COULD RECEIVE MORE FREEZING RAIN AND SLEET THAN PREVIOUSLY EXPECTED THIS MORNING/AFTERNOON. IF ONE IS TO BUY THE SFC GUIDANCE AS ADVERTISED, THE FREEZING LINE DIPS SOUTHWESTWARD INTO PIKE/WAYNE COUNTIES. THIS REGION WILL BE "ON THE EDGE." SO WHAT WE PROPOSE TO DO IS UPGRADE EASTERN NY COUNTIES TO A WINTER STORM WARNING, AND ADD AN ADVISORY FOR PIKE/SOUTHERN WAYNE. DIFFERENT TIMING SCENARIO BUT SIMILAR RESULTS FOR SOUTHERN TIER OF NY AND OTHER PORTIONS OF NORTHEASTERN PA. COLD AIR IS ALREADY IN PLACE OVER TWIN TIERS, WITH STEUBEN CTY IN MID 20S EARLY THIS MORNING AND UPPER 20S EXTENDING EASTWARD THROUGH BROOME COUNTY. WITH TEMPERATURES THIS FAR BELOW FREEZING, AND EXPECTED TO REMAIN BELOW FREEZING A FEW HOURS LONGER THAN EXPECTED THIS MORNING, WE WILL UPGRADE THIS REGION TO A WARNING TOO FOR FREEZING RAIN AND SLEET. MESO-OBS SHOW TEMPS OVER SULLIVAN AND WYOMING CTYS IN PA HOVERING AROUND FREEZING MARK TOO. AN ADVISORY IS NEEDED HERE. THE LATER CREWS SHOULD BE ABLE TO DROP THIS ADVISORY BY MID MORNING, BUT FOR NOW IT NEEDS TO BE ADDED TO THE SUITE. COLD FRONT PUSHES THROUGH TONIGHT. GIVEN VERY TIGHT TEMP GRADIENT, AND FORECASTED FORCING/OMEGA ALONG THE FRONT, CAN SEE POTENTIAL FOR A SQUALL DROPPING SOUTHEASTWARD WITH FRONT DURING EVENING HOURS. THIS IS SOMETHING WE NEED TO KEEP AN EYE ON UPSTREAM, AS IT WOULD ENTER THE NORTHWESTERN FORECAST AREA JUST AN HOUR OR TWO AFTER PEAK DRIVE TIME. MUCH COLDER AIR WILL SPAWN LAKE EFFECT SNOW SHOWERS TUESDAY AND TUESDAY NIGHT. HOWEVER ORGANIZATION LOOKS WEAK AT THIS POINT, AND AM NOT YET SOLD ON ANYTHING BUT LIGHT ACCUMULATION. DJP && .LONG TERM /TONIGHT THROUGH SUNDAY/... WITH FOCUS ON THE SHORT TERM, WE FOLLOWED HPC GUIDANCE CLOSELY WHICH LOOKED VERY GOOD. SOME LES LIKELY TUES NGT INTO WED ON A COLD NW FLOW, WHICH SHUD DIMINISH ON WED AFTN. THE LAKES ARE VERY MILD FOR THIS TIME OF YEAR, AND COLD AIR TEMPS SUGGEST AT LEAST MDT INSTABILITY. LATEST PROFILES SHOW FAIRLY WELL ALIGNED NW FLOW TUES NGT INTO WED MRNG, WITH INVERSION NEAR 850 MB TUES NGT THEN LOWERING ON WED. LOOKS LIKE POTNL FOR SOME ADVISORY ACCUMS ACRS PORTIONS OF THE FINGER LAKES AND SUSQ RGN. HIGH PRES BUILDS IN FOR WED NGT AND THU WITH FAIR WX. ANOTHER REINFORCING SURGE OF COLD AIR LATE IN THE WEEK WITH A CHANCE OF SNOW SHOWERS. && .AVIATION /06Z-06Z/... STARTING CONDITIONS MOSTLY MVFR TO VFR. EXCEPTION IS BGM WITH IFR VSBY AND LIFR CIG. AS STEADY PRECIP MOVES IN THE NEXT 3 HOURS CONDITIONS WILL DROP TO IFR/LIFR CIGS EVERYWHERE FROM SW TO NE. VSBYS MAY STAY AT MVFR ALL BUT BGM. PRECIP TYPES WILL BE RAIN AT AVP...SNPL AT RME AND MAYBE SYR...AND FZRA ALL OTHERS. WINDS NE TO E AT 5 TO 10 KTS. PRECIP TO CHANGE TO JUST RAIN FROM SW TO NE DURING THE DAY MONDAY AS CIGS RISE SOME TO MVFR AS THE WARM FRONT LIFTS THROUGH IN THE AFTN BRIEFLY. WINDS SHIFT TO S TO SW AT 5 TO 10 KTS. COLD FRONT FROM 23Z TO 02Z WILL SHIFT THE WINDS TO W TO NW AT 5 TO 10 KTS. ALL SITES IMPROVE TO MVFR/VFR CIGS AND VSBYS. STEADY PRECIP ENDS. IF ANYTHING THEN SOME SCT LIGHT SNOW SHOWERS BUT NOT MENTIONED THAT FAR OUT IN TAFS. TAC && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. PA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-048-072. && $$ SHORT TERM...DJP AVIATION...TAC ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1157 AM EST SUN JAN 14 2007 .SHORT TERM /REST OF TODAY/... LOTS OF MESONET SITES STILL BELOW FREEZING TO THE NORTH OF A BATH...WATKINS GLEN...HAMILTON AND UTICA LINE. WITH A LIGHT NORTH WIND REINFORCING COLD AIR FROM THE NORTH...DECIDED TO EXTEND THE ADVISORY UNTIL LATER THIS AFTERNOON...ESPECIALLY SINCE NEXT SLUG OF MDT PRECIP MOVING INTO WRN NY MAY CHANGE THERMAL PROFILE TO CREATE MORE OF A MIX. STILL THINK LIGHT ICING WILL OCCUR ACROSS THE FINGER LAKES AND WRN MHWK VALLEY. ELSEWHERE...JUST MINOR TWEEKS TO THE POSITION OF WHERE IT IS MAINLY RAIN...VERSUS THE MIX AND TO LOWER TEMPS UP NORTH A TAD. RADAR TRENDS AND LATEST GUIDANCE SUGGESTS THAT PRECIP TAPERS OFF TO MIXED DRIZZLE OR FLURRIES FOR A WHILE EARLY THIS EVENING WITH COLDER SFC HIGH BUILDING FURTHER SWD. WILL COMMENT MORE ABOUT STRONGER WAVE LATER THIS AFTERNOON AFTER WE IRON OUT MORE DETAILS...BUT INITIAL THOUGHTS HAVE US WORRIED ABOUT A MAJOR ICE STORM IN THE FINGER LAKES AND UPPER SUSQUEHANNA REGION...AS WELL AS THE MOUNTAIN TOPS OF THE WRN CATSKILLS. PROBABLY COLD ENOUGH FOR DECENT ACCUMULATING SNOWS FOR A WHILE NORTH OF SYR-UCA. && .PREV DISCUSSION... /ISSUED 932 AM EST SUN JAN 14 2007/ SHORT TERM /REST OF TODAY/... THE BATTLE GROUND WITH THIS EVENT HAS BEEN DECIDED...AND IT IS HERE IN CNY...PERIOD. FREEZING PRECIP DEMARCATION RIGHT NOW IS NORTH OF A LINE FROM HORNELL-ITH-CORTLAND-OIC-COOPERSTOWN WITH REPORTS OF GLAZING AND TRAVEL PROBLEMS ACROSS THE FINGER LAKES...WRN MHWK VALLEY AND UPPER SUSQUEHANNA REGIONS. CAA AT 1000-925 MB PROGGED TO INCREASE SLOWLY SOUTHWARD BY THE RUC/NAM MODELS THIS AFTERNOON...AND THIS IS BEING REALIZED ALREADY WITH CHANGEOVER TO SNOW AT ROC-FZY. SRN EXTENT OF AIRMASS NOT LIKELY TO BUDGE MUCH TODAY WITH TYPICAL DIURNAL TRENDS CAUSING A FEW DEGREE RISES ABOVE FRZG. THIS LATEST UPDATE WAS TO INCREASE TO CATEGORICAL POPS AS WAVE PRODUCING MIXED PRECIP OVER MI MOVES EAST THIS AFTERNOON WITH ANOTHER SLUG OF MOISTURE. CHANGED SOME PTYPES THIS AFTERNOON UP NORTH TO INCLUDE BURSTS OF SLEET/SNOW AND EVEN RAIN...BUT DID NOT EXTEND ADVISORIES ACROSS THE NORTH COUNTRY JUST YET SO WE CAN WATCH SFC TEMP TRENDS UNTIL 11 AM OR SO TO SEE IF THEY RECOVER. OUR HUNCH IS THOUGH THAT AN EXTENSION OF ADVISORIES THROUGH THE AFTERNOON IS LIKELY ACROSS THE NORTH. TONIGHT STILL LOOKS VERY INTERESTING...WITH POTENTIAL FOR DANGEROUS ICE STORM STILL LOOMING OVER OUR NORTHERN AREAS ESPECIALLY. MORE LATER. PREV DISCUSSION... /ISSUED 703 AM EST SUN JAN 14 2007/ UPDATE... ADDED NRN ZONES TO ADVISORY THIS MRNG DUE TO FZDZ AND FZRA. PREV DISCUSSION... /ISSUED 642 AM EST SUN JAN 14 2007/ AVIATION /12Z-12Z/... IFR TO LIFR CONDITIONS WILL BE WDSPRD ACRS THE RGN TDA AND TNGT WITH LOW CLDS, FOG AND PCPN. OCNL VLIFR CONDITIONS AT ITH/BGM AND AVP THRU 16Z THIS MRNG. -FZRA SHUD CHGOVR TO -RA AT ACRS THE SRN TIER OF NY BETWEEN 14-16Z...AND ARND 16Z AT SYR. MORE MIXED PCPN WILL MOVE IN TNGT ACRS UPSTATE NY, WITH -RA AT AVP, AND A CONTINUATION OF IFR TO LIFR CONDITIONS ALL SITES. WINDS < 10 KTS. PREV DISCUSSION... /ISSUED 210 AM EST SUN JAN 14 2007/ SHORT TERM /TODAY THROUGH MONDAY NIGHT/... LATEST MODEL RUNS DID NOT SHOW AS MUCH CHANGE AS DID PRIOR RUNS, THOUGH BOTH NAM AND COOLER GFS CONTINUE TO PUSH WARM AIR FURTHER NORTHWARD. WHAT IS OBVIOUS IS NORTHERN PORTION OF FA WILL EXPERIENCE A SIGNIFICANT MIXED PRECIPITATION EVENT, WITH AN ELONGATED PERIOD OF FREEZING RAIN EXPECTED. EXACTLY WHERE TO DRAW THE LINE IS THE DIFFICULT PART. BASED ON CURRENT OBS SHOWING COLD AIR PUSHING SOUTHEAST UNDER DOME OF HIGH PRESSURE, WE WENT A TAD COOLER THAN THE CURRENT NAM SOLUTION AT THE LOWEST LEVELS. THE AREA FROM SYR OVER TO RME/UCA LOOKS MOST DANGEROUS, WITH FORECAST SOUNDINGS SUGGESTING PREDOMINANT FREEZING RAIN THIS EVENING INTO MONDAY EVENING. SLEET AND SNOW WILL MIX IN TOO, BUT WE THINK SNOW ACCUMS WILL BE IN 1-4 INCH RANGE WITH THE HIGHEST AMTS ON THE HIGH TERRAIN OF ONEIDA/MADISON COUNTIES, AND POSSIBLY DOWN TOWARD CICERO IN ONONDAGA. JUST CANNOT GET EXCITED ABOUT SNOW IN THIS REGION GIVEN HEIGHT OF DENDRITE LAYER. THE MAIN STORY WILL BE THE FREEZING RAIN. SOUTH TO THE TWIN TIERS, THE SOUNDINGS ARE NOT AS CLEAR CUT. ITH NAM SOUNDING, AGAIN WITH SOME SFC MODIFICATION, SUGGESTS FREEZING RAIN MUCH OF SUNDAY NIGHT AND EARLY MONDAY MORNING. THEN ENOUGH WARM AIR PUSHES NORTH TO CHANGE PRECIP TO ALL RAIN. ELM AND BGM PAINT SIMILAR PICTURES. THE COLD FRONT RIPS THROUGH AROUND 0Z TUESDAY. THERE COULD BE A 2-4 HOUR PERIOD OF SNOW SHOWERS, PROBABLY WITH SOME ACCUMULATION AS DENDRITE LAYER LOWERS FAST. HOWEVER DRIER AIR WORKS IN QUICKLY AND SHOULD CUT OFF BULK OF PRECIP. WITH THAT IN MIND WE ARE ISSUING A WINTER STORM WARNING FOR OUR NORTHERN FA, DOWN THROUGH CORTLAND-CHENANGO COUNTIES. THE TWIN TIERS WILL BE PLACED IN A WINTER WEATHER ADVISORY. DJP PREV DISCUSSION... /ISSUED 1037 PM EST SAT JAN 13 2007/ SHORT TERM /REST OF TONIGHT/... FREEZING LINE HAS EASED SLOWLY SOUTH REACHING TO ABOUT THE NY/PA BORDER AS OF LATE THIS EVENING. PRECIPITATION SO FAR HAS BEEN NOT MUCH MORE THAN SOME VERY LIGHT DRIZZLE, FREEZING DRIZZLE OR A FEW ICE PELLETS. EXPECT SPOTTY LIGHT PRECPITATION TO DEVELOP OVER PA DURING THE NEXT FEW HOURS IN AREA OF WEAK ISENTROPIC LIFT... THEN MOVE NORTHEAST REACHING NORTHERN PA AND SOUTHERN NY SHORTLY AFTER MIDNIGHT... AND THE NORTHERN FINGER LAKES TO WESTERN MOHAWK VALLEY AREA SHORTLY BEFORE DAYBREAK. PRECIPITATION AMOUNTS OVERNIGHT ACROSS THE CWA WILL BE A TENTH OF AN INCH OR LESS... BUT THIS COULD STILL CAUSE SOME ICING ACROSS NORTHERN PA AND NY STATE AS TEMPS WILL BE NEAR TO BELOW FREEZING. HOWEVER OVERALL THREAT FOR A HIGH-END ADVISORY EVENT APPEARS TO BE DIMINISHING. TEMPERATURES WILL RISE ABOVE FREEZING IN MOST AREAS BY LATE SUNDAY MORNING. BEFORE THAT HAPPENS THERE COULD STILL BE SOME SPOTTY LIGHT FREEZING RAIN ACROSS FAR NRN PA AND SOUTHERN NY... AND SOME SPOTTY LIGHT SNOW... SLEET OR FREEZING RAIN IN THE NORTHERN FINGER LAKES AND WESTERN MOHAWK VALLEY. ANY LIGHT PRECIPITATION THAT OCCURS SUNDAY AFTERNOON SHOULD BE IN LIQUID FORM AS SFC TEMPERATURES WILL BE WELL ABOVE FREEZING EVEN ACROSS THE NORTH. MODELS STILL IN SOME DISAGREEMENT ON THE TRACK OF THE SFC LOW AND CHARACTERISTICS OF THERMAL FIELDS FOR SUNDAY NIGHT AND MONDAY. NAM IS FARTHER NORTH AND WARMER THAN THE GFS. 18Z NAM TRENDED SOUTH AND SLIGHTLY COOLER... HOWEVER THE 00Z NAM HAS SHIFTED SLIGHTLY BACK TO THE NORTH. THE SOUTHERN HALF OF THE WATCH AREA STILL APPEARS TO HAVE A GOOD CHANCE FOR SIGNIFICANT ICING LATE SUNDAY NIGHT OR MONDAY... ESPECIALLY IF THE COLDER GFS VERIFIES. NORTHERN AREAS UP NEAR THE NY THRUWAY ARE LOOKING AT THE POTENTIAL FOR SIGNIFICANT ACCUMULATIONS OF ICE IF THE NAM VERIFIES... AND A MIX OF ICE AND SNOW IF THE GFS IS BETTER. & PREV DISCUSSION... /ISSUED 701 PM EST SAT JAN 13 2007/ AVIATION /00Z-24Z/... FOR KELM/KITH/KBGM/KAVP IFR/LIFR CONDITIONS WILL DOMINATE THROUGH MIDDAY SUNDAY DUE TO CIGS. AFTER 06Z, LIGHT FREEZING RAIN WILL OVERSPREAD THE REGION WITH JUST PLAIN RAIN AT KAVP. AFTER 12Z-13Z, THE FREEZING RAIN AT KELM/KITH/KBGM WILL CHANGE TO DRIZZLE AND END AROUND 16Z. AFTER 16Z, CIGS MAY LIFT TO LOW MVFR. AT KRME/KSYR, MVFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. BTW 08Z-12Z LIGHT FREEZING RAIN AND SNOW IS POSSIBLE WITH OCCASIONAL IFR CIGS AT KRME. WINDS WILL BE LIGHT THROUGH THE PERIOD GENERALLY LESS THAN 5 KNOTS. PREV DISCUSSION... /ISSUED 358 PM EST SAT JAN 13 2007/ LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... A PTRN MORE TYPICAL OF MID WINTER WILL BE THE MAIN THEME IN THE XTNDD FCST, WITH MEAN TROF PSN OVER THE ERN U.S.. SYSTEM RESPONSIBLE FOR THIS WEEKEND`S MIXED PCPN WILL BE DEPARTING, LEAVING COLD TEMPS AND NW FLOW IN IT`S WAKE. WE RAISED POPS AND SKY COVER ABV HPC GUIDANCE FOR TUES/TUES NGT GIVEN LIKLIHOOD OF LES ACTIVITY. DIFFERING SIGS W/RESPECT TO ACCUM POTNL...EARLIER GFS RUNS WERE PAINTING NNW FLOW...FAVORING LES ACTIVITY ACRS THE FINGER LAKES AND CNRTL SRN TIER....AND POTNL DVLPMNT OF FINGER LAKES BANDS...BUT LATEST RUNS INDICATE FLOW MAY BE MORE NWLY WHICH WOULD INDICATE INCREASED POTNL FOR SOME ADVISORY ACCUMS. THIS WILL HAVE TO BE ADDRESSED IN LATER PCKGS. FAIR WX FOR MID WEEK AS HIGH PRES BUILDS IN WITH MODERATING TEMPS, THEN ERN U.S. TROF RE-AMPLIFIES WITH CHC FOR PCPN LATE IN THE WEEK. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR NYZ022-024-055>057-062. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR NYZ009-015>018-023-025-036-037-044>046. WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ009-015>018-022-023-025-036-037. PA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR PAZ038>040. && $$ SHORT TERM...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 932 AM EST SUN JAN 14 2007 .SHORT TERM /REST OF TODAY/... THE BATTLE GROUND WITH THIS EVENT HAS BEEN DECIDED...AND IT IS HERE IN CNY...PERIOD. FREEZING PRECIP DEMARCATION RIGHT NOW IS NORTH OF A LINE FROM HORNELL-ITH-CORTLAND-OIC-COOPERSTOWN WITH REPORTS OF GLAZING AND TRAVEL PROBLEMS ACROSS THE FINGER LAKES...WRN MHWK VALLEY AND UPPER SUSQUEHANNA REGIONS. CAA AT 1000-925 MB PROGGED TO INCREASE SLOWLY SOUTHWARD BY THE RUC/NAM MODELS THIS AFTERNOON...AND THIS IS BEING REALIZED ALREADY WITH CHANGEOVER TO SNOW AT ROC-FZY. SRN EXTENT OF AIRMASS NOT LIKELY TO BUDGE MUCH TODAY WITH TYPICAL DIURNAL TRENDS CAUSING A FEW DEGREE RISES ABOVE FRZG. THIS LATEST UPDATE WAS TO INCREASE TO CATEGORICAL POPS AS WAVE PRODUCING MIXED PRECIP OVER MI MOVES EAST THIS AFTERNOON WITH ANOTHER SLUG OF MOISTURE. CHANGED SOME PTYPES THIS AFTERNOON UP NORTH TO INCLUDE BURSTS OF SLEET/SNOW AND EVEN RAIN...BUT DID NOT EXTEND ADVISORIES ACROSS THE NORTH COUNTRY JUST YET SO WE CAN WATCH SFC TEMP TRENDS UNTIL 11 AM OR SO TO SEE IF THEY RECOVER. OUR HUNCH IS THOUGH THAT AN EXTENSION OF ADVISORIES THROUGH THE AFTERNOON IS LIKELY ACROSS THE NORTH. TONIGHT STILL LOOKS VERY INTERESTING...WITH POTENTIAL FOR DANGEROUS ICE STORM STILL LOOMING OVER OUR NORTHERN AREAS ESPECIALLY. MORE LATER. && .PREV DISCUSSION... /ISSUED 703 AM EST SUN JAN 14 2007/ UPDATE... ADDED NRN ZONES TO ADVISORY THIS MRNG DUE TO FZDZ AND FZRA. PREV DISCUSSION... /ISSUED 642 AM EST SUN JAN 14 2007/ AVIATION /12Z-12Z/... IFR TO LIFR CONDITIONS WILL BE WDSPRD ACRS THE RGN TDA AND TNGT WITH LOW CLDS, FOG AND PCPN. OCNL VLIFR CONDITIONS AT ITH/BGM AND AVP THRU 16Z THIS MRNG. -FZRA SHUD CHGOVR TO -RA AT ACRS THE SRN TIER OF NY BETWEEN 14-16Z...AND ARND 16Z AT SYR. MORE MIXED PCPN WILL MOVE IN TNGT ACRS UPSTATE NY, WITH -RA AT AVP, AND A CONTINUATION OF IFR TO LIFR CONDITIONS ALL SITES. WINDS < 10 KTS. PREV DISCUSSION... /ISSUED 210 AM EST SUN JAN 14 2007/ SHORT TERM /TODAY THROUGH MONDAY NIGHT/... LATEST MODEL RUNS DID NOT SHOW AS MUCH CHANGE AS DID PRIOR RUNS, THOUGH BOTH NAM AND COOLER GFS CONTINUE TO PUSH WARM AIR FURTHER NORTHWARD. WHAT IS OBVIOUS IS NORTHERN PORTION OF FA WILL EXPERIENCE A SIGNIFICANT MIXED PRECIPITATION EVENT, WITH AN ELONGATED PERIOD OF FREEZING RAIN EXPECTED. EXACTLY WHERE TO DRAW THE LINE IS THE DIFFICULT PART. BASED ON CURRENT OBS SHOWING COLD AIR PUSHING SOUTHEAST UNDER DOME OF HIGH PRESSURE, WE WENT A TAD COOLER THAN THE CURRENT NAM SOLUTION AT THE LOWEST LEVELS. THE AREA FROM SYR OVER TO RME/UCA LOOKS MOST DANGEROUS, WITH FORECAST SOUNDINGS SUGGESTING PREDOMINANT FREEZING RAIN THIS EVENING INTO MONDAY EVENING. SLEET AND SNOW WILL MIX IN TOO, BUT WE THINK SNOW ACCUMS WILL BE IN 1-4 INCH RANGE WITH THE HIGHEST AMTS ON THE HIGH TERRAIN OF ONEIDA/MADISON COUNTIES, AND POSSIBLY DOWN TOWARD CICERO IN ONONDAGA. JUST CANNOT GET EXCITED ABOUT SNOW IN THIS REGION GIVEN HEIGHT OF DENDRITE LAYER. THE MAIN STORY WILL BE THE FREEZING RAIN. SOUTH TO THE TWIN TIERS, THE SOUNDINGS ARE NOT AS CLEAR CUT. ITH NAM SOUNDING, AGAIN WITH SOME SFC MODIFICATION, SUGGESTS FREEZING RAIN MUCH OF SUNDAY NIGHT AND EARLY MONDAY MORNING. THEN ENOUGH WARM AIR PUSHES NORTH TO CHANGE PRECIP TO ALL RAIN. ELM AND BGM PAINT SIMILAR PICTURES. THE COLD FRONT RIPS THROUGH AROUND 0Z TUESDAY. THERE COULD BE A 2-4 HOUR PERIOD OF SNOW SHOWERS, PROBABLY WITH SOME ACCUMULATION AS DENDRITE LAYER LOWERS FAST. HOWEVER DRIER AIR WORKS IN QUICKLY AND SHOULD CUT OFF BULK OF PRECIP. WITH THAT IN MIND WE ARE ISSUING A WINTER STORM WARNING FOR OUR NORTHERN FA, DOWN THROUGH CORTLAND-CHENANGO COUNTIES. THE TWIN TIERS WILL BE PLACED IN A WINTER WEATHER ADVISORY. DJP PREV DISCUSSION... /ISSUED 1037 PM EST SAT JAN 13 2007/ SHORT TERM /REST OF TONIGHT/... FREEZING LINE HAS EASED SLOWLY SOUTH REACHING TO ABOUT THE NY/PA BORDER AS OF LATE THIS EVENING. PRECIPITATION SO FAR HAS BEEN NOT MUCH MORE THAN SOME VERY LIGHT DRIZZLE, FREEZING DRIZZLE OR A FEW ICE PELLETS. EXPECT SPOTTY LIGHT PRECPITATION TO DEVELOP OVER PA DURING THE NEXT FEW HOURS IN AREA OF WEAK ISENTROPIC LIFT... THEN MOVE NORTHEAST REACHING NORTHERN PA AND SOUTHERN NY SHORTLY AFTER MIDNIGHT... AND THE NORTHERN FINGER LAKES TO WESTERN MOHAWK VALLEY AREA SHORTLY BEFORE DAYBREAK. PRECIPITATION AMOUNTS OVERNIGHT ACROSS THE CWA WILL BE A TENTH OF AN INCH OR LESS... BUT THIS COULD STILL CAUSE SOME ICING ACROSS NORTHERN PA AND NY STATE AS TEMPS WILL BE NEAR TO BELOW FREEZING. HOWEVER OVERALL THREAT FOR A HIGH-END ADVISORY EVENT APPEARS TO BE DIMINISHING. TEMPERATURES WILL RISE ABOVE FREEZING IN MOST AREAS BY LATE SUNDAY MORNING. BEFORE THAT HAPPENS THERE COULD STILL BE SOME SPOTTY LIGHT FREEZING RAIN ACROSS FAR NRN PA AND SOUTHERN NY... AND SOME SPOTTY LIGHT SNOW... SLEET OR FREEZING RAIN IN THE NORTHERN FINGER LAKES AND WESTERN MOHAWK VALLEY. ANY LIGHT PRECIPITATION THAT OCCURS SUNDAY AFTERNOON SHOULD BE IN LIQUID FORM AS SFC TEMPERATURES WILL BE WELL ABOVE FREEZING EVEN ACROSS THE NORTH. MODELS STILL IN SOME DISAGREEMENT ON THE TRACK OF THE SFC LOW AND CHARACTERISTICS OF THERMAL FIELDS FOR SUNDAY NIGHT AND MONDAY. NAM IS FARTHER NORTH AND WARMER THAN THE GFS. 18Z NAM TRENDED SOUTH AND SLIGHTLY COOLER... HOWEVER THE 00Z NAM HAS SHIFTED SLIGHTLY BACK TO THE NORTH. THE SOUTHERN HALF OF THE WATCH AREA STILL APPEARS TO HAVE A GOOD CHANCE FOR SIGNIFICANT ICING LATE SUNDAY NIGHT OR MONDAY... ESPECIALLY IF THE COLDER GFS VERIFIES. NORTHERN AREAS UP NEAR THE NY THRUWAY ARE LOOKING AT THE POTENTIAL FOR SIGNIFICANT ACCUMULATIONS OF ICE IF THE NAM VERIFIES... AND A MIX OF ICE AND SNOW IF THE GFS IS BETTER. & PREV DISCUSSION... /ISSUED 701 PM EST SAT JAN 13 2007/ AVIATION /00Z-24Z/... FOR KELM/KITH/KBGM/KAVP IFR/LIFR CONDITIONS WILL DOMINATE THROUGH MIDDAY SUNDAY DUE TO CIGS. AFTER 06Z, LIGHT FREEZING RAIN WILL OVERSPREAD THE REGION WITH JUST PLAIN RAIN AT KAVP. AFTER 12Z-13Z, THE FREEZING RAIN AT KELM/KITH/KBGM WILL CHANGE TO DRIZZLE AND END AROUND 16Z. AFTER 16Z, CIGS MAY LIFT TO LOW MVFR. AT KRME/KSYR, MVFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. BTW 08Z-12Z LIGHT FREEZING RAIN AND SNOW IS POSSIBLE WITH OCCASIONAL IFR CIGS AT KRME. WINDS WILL BE LIGHT THROUGH THE PERIOD GENERALLY LESS THAN 5 KNOTS. PREV DISCUSSION... /ISSUED 358 PM EST SAT JAN 13 2007/ LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... A PTRN MORE TYPICAL OF MID WINTER WILL BE THE MAIN THEME IN THE XTNDD FCST, WITH MEAN TROF PSN OVER THE ERN U.S.. SYSTEM RESPONSIBLE FOR THIS WEEKEND`S MIXED PCPN WILL BE DEPARTING, LEAVING COLD TEMPS AND NW FLOW IN IT`S WAKE. WE RAISED POPS AND SKY COVER ABV HPC GUIDANCE FOR TUES/TUES NGT GIVEN LIKLIHOOD OF LES ACTIVITY. DIFFERING SIGS W/RESPECT TO ACCUM POTNL...EARLIER GFS RUNS WERE PAINTING NNW FLOW...FAVORING LES ACTIVITY ACRS THE FINGER LAKES AND CNRTL SRN TIER....AND POTNL DVLPMNT OF FINGER LAKES BANDS...BUT LATEST RUNS INDICATE FLOW MAY BE MORE NWLY WHICH WOULD INDICATE INCREASED POTNL FOR SOME ADVISORY ACCUMS. THIS WILL HAVE TO BE ADDRESSED IN LATER PCKGS. FAIR WX FOR MID WEEK AS HIGH PRES BUILDS IN WITH MODERATING TEMPS, THEN ERN U.S. TROF RE-AMPLIFIES WITH CHC FOR PCPN LATE IN THE WEEK. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR NYZ022-024-055>057-062. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR NYZ009-015>018-023-025-036-037-044>046. PA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ038>040. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST MONDAY FOR PAZ038>040. && $$ SHORT TERM...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1256 PM EST MON JAN 15 2007 .AVIATION /18Z-18Z/... RAIN WILL MOVE EAST OF THE TERMINALS WITHIN THE NEXT HOUR. CEILINGS WILL GENERALLY BE MVFR ALTHOUGH SOME AREAS OF IFR WILL OCCUR INTO THE EVENING. THERE COULD BE SOME TEMPORARY BREAKS IN THE CEILING BETWEEN 06Z AND 12Z BUT MVFR SHOULD PREVAIL TO THE END OF THE FORECAST PERIOD. FLURRIES OR SNOW SHOWERS WILL BE POSSIBLE TOMORROW BUT THE PROBABILITY OF THEM OCCURRING AT ANY ONE SITE IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. WINDS WILL VEER TO WEST THIS EVENING AND THEN WEST NORTHWEST ON TUESDAY. && .PREV DISCUSSION... /ISSUED 1135 AM EST MON JAN 15 2007/ SHORT TERM /REST OF TODAY/... BACK EDGE OF THE RAIN IS FINALLY MOVING ACROSS THE FORECAST AREA AND SHOULD CONTINUE TO DO SO THROUGH THE AFTERNOON. DECIDED TO EXTEND THE FLOOD WATCH FOR THE SOUTHEAST HALF WHERE SOME MODERATE RAIN IS STILL POSSIBLE. MADE SOME MINOR MODIFICATIONS TO TEMPERATURES BASED ON LATEST OBSERVATIONS AND SHORT TERM MODEL GUIDANCE. SHORT TERM /TODAY THROUGH WEDNESDAY/... SFC LOW IS NR OF IND...WITH A WRMFNT RUNNING NE UP TO NR AOH AND FDY. POSITION OF THE LOW IS WEST OF ALL THE MODELS...WHICH SHOULD MEAN THAT TEMPS AT 12Z WILL BE WARMER THAN GUIDANCE. USED THE RAW RUC/NAM12 SFC TEMPS FOR MY 12Z TEMPS AND MADE THEM MY HIGH TEMPS. WITH LOW PULLS NE COLDER AIR WILL WORK INTO THE REGION THIS AFTERNOON. RAIN WILL GRADUALLY CHANGE TO SNOW IN THE NW HALF TODAY...THEN ACROSS THE SE TONIGHT. MODELS DRAG A PERIOD OF MODERATE TO HEAVY RAIN ACRS THE FA THIS MORNING. WILL LEAVE FFA UP THRU EXPIRATION TIME. PCPN WILL TAPER OFF QUICKLY THIS AFTERNOON. NORTHERLY FLOW OVER THE LAKES WILL PRODUCE SNOW SHOWERS TONIGHT INTO EARLY TUE EVENING. HIGH BUILDS IN TUE NGT INTO WED. FOR TEMPS THE REST OF THE FORECAST PERIOD....USED A BLEND OF GUIDANCE. SITES LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO CHANGE TO PREVIOUS FORECAST. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR OHZ054>056-063>065- 070>074-077>082-088. KY...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR KYZ089>100. IN...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR INZ066-073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1135 AM EST MON JAN 15 2007 .SHORT TERM /REST OF TODAY/... BACK EDGE OF THE RAIN IS FINALLY MOVING ACROSS THE FORECAST AREA AND SHOULD CONTINUE TO DO SO THROUGH THE AFTERNOON. DECIDED TO EXTEND THE FLOOD WATCH FOR THE SOUTHEAST HALF WHERE SOME MODERATE RAIN IS STILL POSSIBLE. MADE SOME MINOR MODIFICATIONS TO TEMPERATURES BASED ON LATEST OBSERVATIONS AND SHORT TERM MODEL GUIDANCE. && .PREV DISCUSSION... /ISSUED 650 AM EST MON JAN 15 2007/ AVIATION /12Z-12Z/... SFC LOW QUICLY MOVING NE THROUGH OHVLY...CURRENTLY LOCATED OVER LIMA. NEARLY STATIONARY COLD FRONT BISECTING THE REGION FROM SW-NE WILL MAKE AN EASTWARD PUSH AS SFC COLD AIR SWINGS THROUGH THE REGION. TRIED TO BE A LITTLE OPTIMISTIC ON CIGS FOR ALL BUT KDAY TAFS TODAY...AT LEAST UNTIL WINDS SHIFT MORE WESTERLY AND CIGS DROP TOWARDS THE IFR CATEGORY. COLD POOL WILL HAVE MORE OF AN EFFECT OF DRYING OUT THE AIR THIS AFTERNOON AND EVENING VERSUS CHANGING RAIN OVER TO SNOW. BELIEVE THAT ISOLD -SHSN WILL OCCUR THIS EVENING BUT THERE IS NOT ANY PARTICULAR AREA FOR DEVELOPMENT. CONTINUE TO LEAVE OUT OF FCST AS THEY SHOULDN`T AFFECT VSBYS ALL THAT MUCH...OR AT LEAST BE MORE MISS THAN HIT. FRANKS SHORT TERM /TODAY THROUGH WEDNESDAY/... SFC LOW IS NR OF IND...WITH A WRMFNT RUNNING NE UP TO NR AOH AND FDY. POSITION OF THE LOW IS WEST OF ALL THE MODELS...WHICH SHOULD MEAN THAT TEMPS AT 12Z WILL BE WARMER THAN GUIDANCE. USED THE RAW RUC/NAM12 SFC TEMPS FOR MY 12Z TEMPS AND MADE THEM MY HIGH TEMPS. WITH LOW PULLS NE COLDER AIR WILL WORK INTO THE REGION THIS AFTERNOON. RAIN WILL GRADUALLY CHANGE TO SNOW IN THE NW HALF TODAY...THEN ACROSS THE SE TONIGHT. MODELS DRAG A PERIOD OF MODERATE TO HEAVY RAIN ACRS THE FA THIS MORNING. WILL LEAVE FFA UP THRU EXPIRATION TIME. PCPN WILL TAPER OFF QUICKLY THIS AFTERNOON. NORTHERLY FLOW OVER THE LAKES WILL PRODUCE SNOW SHOWERS TONIGHT INTO EARLY TUE EVENING. HIGH BUILDS IN TUE NGT INTO WED. FOR TEMPS THE REST OF THE FORECAST PERIOD....USED A BLEND OF GUIDANCE. SITES LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO CHANGE TO PREVIOUS FORECAST. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR OHZ054>056- 063>065-070>074-077>082-088. KY...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR KYZ089>100. IN...FLOOD WATCH UNTIL 4 PM EST THIS AFTERNOON FOR INZ066-073>075- 080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 650 AM EST MON JAN 15 2007 .AVIATION /12Z-12Z/... SFC LOW QUICLY MOVING NE THROUGH OHVLY...CURRENTLY LOCATED OVER LIMA. NEARLY STATIONARY COLD FRONT BISECTING THE REGION FROM SW-NE WILL MAKE AN EASTWARD PUSH AS SFC COLD AIR SWINGS THROUGH THE REGION. TRIED TO BE A LITTLE OPTIMISTIC ON CIGS FOR ALL BUT KDAY TAFS TODAY...AT LEAST UNTIL WINDS SHIFT MORE WESTERLY AND CIGS DROP TOWARDS THE IFR CATEGORY. COLD POOL WILL HAVE MORE OF AN EFFECT OF DRYING OUT THE AIR THIS AFTERNOON AND EVENING VERSUS CHANGING RAIN OVER TO SNOW. BELIEVE THAT ISOLD -SHSN WILL OCCUR THIS EVENING BUT THERE IS NOT ANY PARTICULAR AREA FOR DEVELOPMENT. CONTINUE TO LEAVE OUT OF FCST AS THEY SHOULDN`T AFFECT VSBYS ALL THAT MUCH...OR AT LEAST BE MORE MISS THAN HIT. FRANKS && .SHORT TERM /TODAY THROUGH WEDNESDAY/... SFC LOW IS NR OF IND...WITH A WRMFNT RUNNING NE UP TO NR AOH AND FDY. POSITION OF THE LOW IS WEST OF ALL THE MODELS...WHICH SHOULD MEAN THAT TEMPS AT 12Z WILL BE WARMER THAN GUIDANCE. USED THE RAW RUC/NAM12 SFC TEMPS FOR MY 12Z TEMPS AND MADE THEM MY HIGH TEMPS. WITH LOW PULLS NE COLDER AIR WILL WORK INTO THE REGION THIS AFTERNOON. RAIN WILL GRADUALLY CHANGE TO SNOW IN THE NW HALF TODAY...THEN ACROSS THE SE TONIGHT. MODELS DRAG A PERIOD OF MODERATE TO HEAVY RAIN ACRS THE FA THIS MORNING. WILL LEAVE FFA UP THRU EXPIRATION TIME. PCPN WILL TAPER OFF QUICKLY THIS AFTERNOON. NORTHERLY FLOW OVER THE LAKES WILL PRODUCE SNOW SHOWERS TONIGHT INTO EARLY TUE EVENING. HIGH BUILDS IN TUE NGT INTO WED. FOR TEMPS THE REST OF THE FORECAST PERIOD....USED A BLEND OF GUIDANCE. SITES && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO CHANGE TO PREVIOUS FORECAST. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR OHZ026-034-035- 042>046-051>056-060>065-070>074-077>082-088. KY...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR KYZ089>100. IN...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR INZ050-058-059- 066-073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 349 AM EST MON JAN 15 2007 .SHORT TERM /TODAY THROUGH WEDNESDAY/... SFC LOW IS NR OF IND...WITH A WRMFNT RUNNING NE UP TO NR AOH AND FDY. POSITION OF THE LOW IS WEST OF ALL THE MODELS...WHICH SHOULD MEAN THAT TEMPS AT 12Z WILL BE WARMER THAN GUIDANCE. USED THE RAW RUC/NAM12 SFC TEMPS FOR MY 12Z TEMPS AND MADE THEM MY HIGH TEMPS. WITH LOW PULLS NE COLDER AIR WILL WORK INTO THE REGION THIS AFTERNOON. RAIN WILL GRADUALLY CHANGE TO SNOW IN THE NW HALF TODAY...THEN ACROSS THE SE TONIGHT. MODELS DRAG A PERIOD OF MODERATE TO HEAVY RAIN ACRS THE FA THIS MORNING. WILL LEAVE FFA UP THRU EXPIRATION TIME. PCPN WILL TAPER OFF QUICKLY THIS AFTERNOON. NORTHERLY FLOW OVER THE LAKES WILL PRODUCE SNOW SHOWERS TONIGHT INTO EARLY TUE EVENING. HIGH BUILDS IN TUE NGT INTO WED. FOR TEMPS THE REST OF THE FORECAST PERIOD....USED A BLEND OF GUIDANCE. SITES && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO CHANGE TO PREVIOUS FORECAST. && .AVIATION /06Z-06Z/... SFC LOW HAS TRANSLATED A GOOD BIT OF ENERGY TO THE NE ALONG THE FRONT AND IS CURRENTLY LOCATED JUST NW OF KY/IL/IN BORDER. FRONT TRAVELS ENE THROUGH OHVLY...STAYING JUST N OF OHRIVER AS IT CUTS THROUGH ILN AND PBZ. CIGS AND VSBYS SE OF THE FRONT WILL REMAIN VFR AS WINDS PICK UP FROM THE S AROUND 8-12KTS. THE SFC LOW TRACKS QUICKLY NE THROUGH IN AND OH...REACHING WRN NY BY NOON. FOR THE MAJORITY OF THE MORNING...WINDS WILL PICK UP FROM THE SW AND BE GUSTY IN A FAIRLY STEADY RAINFALL. A WEAK WIND SHIFT TO THE WEST WILL MARK THE FRONAL PASSAGE...QUICKLY TURNING OFF THE RAINFALL THIS AFTERNOON FROM NW-SE. WAS A LITTLE MORE OPTIMISTIC IN THE CIGS TODAY...ONCE WINDS PICK UP THEY SHOULD STAY OUT OF THE PESKY IFR/LIFR CATEGORY THAT HAS PREVAILED FOR THE PAST FEW DAYS. ISOLD -SHSN MAY OCCUR FROM 0Z TO 6Z BUT THERE IS NOT ANY PARTICULAR AREA FOR THEM TO OCCUR...HAVE LEFT OUT ATTM AS THEY SHOULDN`T AFFECT VSBYS ALL THAT MUCH...OR AT LEAST BE MORE MISS THAN HIT. && && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR OHZ026-034-035- 042>046-051>056-060>065-070>074-077>082-088. KY...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR KYZ089>100. IN...FLOOD WATCH UNTIL 11 AM EST THIS MORNING FOR INZ050-058-059- 066-073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 111 AM EST MON JAN 15 2007 .AVIATION /6Z-6Z/... SFC LOW HAS TRANSLATED A GOOD BIT OF ENERGY TO THE NE ALONG THE FRONT AND IS CURRENTLY LOCATED JUST NW OF KY/IL/IN BORDER. FRONT TRAVELS ENE THROUGH OHVLY...STAYING JUST N OF OHRIVER AS IT CUTS THROUGH ILN AND PBZ. CIGS AND VSBYS SE OF THE FRONT WILL REMAIN VFR AS WINDS PICK UP FROM THE S AROUND 8-12KTS. THE SFC LOW TRACKS QUICKLY NE THROUGH IN AND OH...REACHING WRN NY BY NOON. FOR THE MAJORITY OF THE MORNING...WINDS WILL PICK UP FROM THE SW AND BE GUSTY IN A FAIRLY STEADY RAINFALL. A WEAK WIND SHIFT TO THE WEST WILL MARK THE FRONAL PASSAGE...QUICKLY TURNING OFF THE RAINFALL THIS AFTERNOON FROM NW-SE. WAS A LITTLE MORE OPTIMISTIC IN THE CIGS TODAY...ONCE WINDS PICK UP THEY SHOULD STAY OUT OF THE PESKY IFR/LIFR CATEGORY THAT HAS PREVAILED FOR THE PAST FEW DAYS. ISOLD -SHSN MAY OCCUR FROM 0Z TO 6Z BUT THERE IS NOT ANY PARTICULAR AREA FOR THEM TO OCCUR...HAVE LEFT OUT ATTM AS THEY SHOULDN`T AFFECT VSBYS ALL THAT MUCH...OR AT LEAST BE MORE MISS THAN HIT. && .PREVIOUS DISCUSSIONS... ISSUED 730 PM EST SUN JAN 14 2007 SHORT TERM /TONIGHT/ ADJUSTED HOURLY TEMPERATURES DOWN SLIGHTLY TO REFLECT CURRENT CONDITIONS. REST OF FORECAST UNCHANGED. ISSUED 525 PM EST SUN JAN 14 2007 SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... FRONT REMAINS DRAPED ACROSS THE AREA. SHOWERS CONTINUE...MAINLY TO THE NORTH OF THE FRONT. A STRONG WAVE OF LOW PRESSURE MOVING UP THE FRONT WILL ENHANCE THE PRECIPITATION AND RESULT IN WIDESPREAD RAINFALL TONIGHT. FLOOD WATCH IS IN EFFECT ALL ZONES. AS THE LOW CONTINUES ON A NORTHEASTERLY TRACK ON MONDAY...IT WILL DRAG THE FRONT EAST OF THE AREA AND ALLOW COLDER AND DRIER AIR TO FILTER IN. TEMPERATURES WILL BE COLD ENOUGH FOR SNOW BY MONDAY NIGHT...AND THOUGH MOISTURE WITH THE LOW WILL BE GONE...THE FLOW BEHIND THE LOW WILL BE CONDUCIVE FOR LAKE ENHANCED SNOW SHOWERS. 850 MB TO LAKE SURFACE TEMPERATURE DIFFERENTIALS WILL BE IMPRESSIVE AT GREATER THAN 15 DEGREES CELSIUS. IN ADDITION...THE RELATIVELY STRONG 850 MB WINDS OF ABOUT 20 KTS AND THE SHALLOW DEPTH OF THE UNSTABLE LAYER WILL ALLOW THE LAKE MOISTURE TO REACH THIS FAR INLAND. WENT WITH A CHANCE OF SNOW SHOWERS MONDAY NIGHT THROUGH TUESDAY AFTERNOON. AS USUAL WITH LAKE EFFECT SITUATIONS IN THE ILN AREA...WE ARE EXPECTING LIGHT SNOW ACCUMULATIONS. SNOW SHOWERS WILL END TUESDAY AFTERNOON WHEN THE AIRMASS BECOMES TO DRY FOR SNOW TO FORM. SKIES WILL BECOME MOSTLY CLEAR TUESDAY NIGHT AS HIGH PRESSURE BUILDS IN. TEMPERATURES ARE VERY TRICKY WITH THE FRONT OVERHEAD. RUC TEMPERATURES APPEARED TO WORK BEST FOR TONIGHT. KEPT CLOSE TO PREVIOUS FORECAST AND BELOW MOS GUIDANCE MONDAY THROUGH TUESDAY. INCREASED TUESDAY NIGHT SLIGHTLY BUT IT MAY STILL BE THE COLDEST NIGHT SO FAR THIS MONTH. DAYTON AND COLUMBUS HAVE BEEN ABOVE NORMAL EVERY DAY SINCE DECEMBER 9...BUT THE STREAK MAY END ON TUESDAY. RIVER FLOODING PROBLEMS PERSIST...THOUGH LAST NIGHT`S RAINFALL WAS NOT AS GREAT AS EXPECTED AND RIVER LEVELS ARE NOT FORECAST TO BE AS HIGH AS PREVIOUSLY THOUGHT. RIVERS FOR WHICH FLOOD WARNINGS HAVE BEEN ISSUED INCLUDE THE SCIOTO RIVER AT CIRCLEVILLE AND PIKETON...THE GREAT MIAMI RIVER AT SIDNEY AND MIAMITOWN...THE HOCKING RIVER AT ENTERPRISE...AND THE OHIO BRUSH CREEK AT WEST UNION. CONIGLIO LONG TERM /WEDNESDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE TO BUILD SE BECOMING CENTERED OVER OHIO ON WED IN NWRLY FLOW ALOFT. THIS HIGH WL PROVIDE DRY WX AND COLDER TEMPS INTO THURSDAY. ARCTIC AIRMASS VERY DRY AND HAVE KNOCKED DOWN SKY COVER AND GENERALLY PREFER TEMPS AT OR SLIGHTLY COLDER THAN GUID VALUES. IN SPLIT FLO REGIME CONFIDENCE ON PRECIP EVENTS AND TIMING IS NOT HIGH. WITH SFC HIGH PRESSURE OFF TO THE EAST ON THU FLO TO BACK WITH WAA PATTERN DEVELOPING. PRECIP POSSIBLE AS EARLY AS THU...BUT WITH OHIO BTWN SRN AND NRN STREAM MOISTURE...WL MAINTAIN A DRY FCST. HAVE HELD BACK THE INTRODUCTION OF PRECIP UNTIL FRIDAY MORNING. MODELS SHOWING SRN MSTR ADVECTING NEWD AHD OF NRN FRONTAL SYSTEM. AT THIS TIME HAVE ONLY OPTD FOR SLIGHT CHC POPS AND BASED ON TOP DOWN APPROACH EXPECT SNOW NORTH AND RAIN AND SNOW SOUTH. THE AREA LOOKS TO DRY OUT LATER ON FRIDAY NIGHT INTO SAT WITH SFC HI PRESSURE BUILDING BACK IN WITH NWRLY FLOW ALOFT DEVELOPING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ026-034-035-042>046- 051>056-060>065-070>074-077>082-088. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066-073> 075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 941 PM EST SUN JAN 14 2007 .AVIATION /00Z-24Z/... WEAK LOW PRESSURE SYSTEM OVER SOUTHERN MO...WITH A QUASI- STATIONARY FRONT EXTENDING EASTWARD ACROSS SOUTHERN OH AND NORTHERN KY...WILL CONTINUE TO AFFECT THE ILN CWA INTO MONDAY. THIS LOW SHOULD CONTINUE TO MOVE NE DURING THE OVERNIGHT HOURS KEEPING THE AREA IN PREDOMINANTLY IFR CONDITIONS WITH LOCALLY LIFR CONDITIONS. THE BETTER FORCING IS FORECAST AFTER 06Z OVER THE SW PART OF OUR AREA...THEN SPREADING NNE AFTER 06Z. HAVE INDICATED AREAS OF MODERATE RAIN BETWEEN 06Z AND 12Z OVER THE SW TAF SITES AND FROM ABOUT 08Z TO 14Z ACROSS THE NE SITES. FRONTAL PASSAGE EXPECTED TOMORROW WITH MVFR CONDITIONS EXPECTED. && .PREV DISCUSSION... /ISSUED 730 PM EST SUN JAN 14 2007/ SHORT TERM /TONIGHT/... ADJUSTED HOURLY TEMPERATURES DOWN SLIGHTLY TO REFLECT CURRENT CONDITIONS. REST OF FORECAST UNCHANGED. SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... FRONT REMAINS DRAPED ACROSS THE AREA. SHOWERS CONTINUE...MAINLY TO THE NORTH OF THE FRONT. A STRONG WAVE OF LOW PRESSURE MOVING UP THE FRONT WILL ENHANCE THE PRECIPITATION AND RESULT IN WIDESPREAD RAINFALL TONIGHT. FLOOD WATCH IS IN EFFECT ALL ZONES. AS THE LOW CONTINUES ON A NORTHEASTERLY TRACK ON MONDAY...IT WILL DRAG THE FRONT EAST OF THE AREA AND ALLOW COLDER AND DRIER AIR TO FILTER IN. TEMPERATURES WILL BE COLD ENOUGH FOR SNOW BY MONDAY NIGHT...AND THOUGH MOISTURE WITH THE LOW WILL BE GONE...THE FLOW BEHIND THE LOW WILL BE CONDUCIVE FOR LAKE ENHANCED SNOW SHOWERS. 850 MB TO LAKE SURFACE TEMPERATURE DIFFERENTIALS WILL BE IMPRESSIVE AT GREATER THAN 15 DEGREES CELSIUS. IN ADDITION...THE RELATIVELY STRONG 850 MB WINDS OF ABOUT 20 KTS AND THE SHALLOW DEPTH OF THE UNSTABLE LAYER WILL ALLOW THE LAKE MOISTURE TO REACH THIS FAR INLAND. WENT WITH A CHANCE OF SNOW SHOWERS MONDAY NIGHT THROUGH TUESDAY AFTERNOON. AS USUAL WITH LAKE EFFECT SITUATIONS IN THE ILN AREA...WE ARE EXPECTING LIGHT SNOW ACCUMULATIONS. SNOW SHOWERS WILL END TUESDAY AFTERNOON WHEN THE AIRMASS BECOMES TO DRY FOR SNOW TO FORM. SKIES WILL BECOME MOSTLY CLEAR TUESDAY NIGHT AS HIGH PRESSURE BUILDS IN. TEMPERATURES ARE VERY TRICKY WITH THE FRONT OVERHEAD. RUC TEMPERATURES APPEARED TO WORK BEST FOR TONIGHT. KEPT CLOSE TO PREVIOUS FORECAST AND BELOW MOS GUIDANCE MONDAY THROUGH TUESDAY. INCREASED TUESDAY NIGHT SLIGHTLY BUT IT MAY STILL BE THE COLDEST NIGHT SO FAR THIS MONTH. DAYTON AND COLUMBUS HAVE BEEN ABOVE NORMAL EVERY DAY SINCE DECEMBER 9...BUT THE STREAK MAY END ON TUESDAY. RIVER FLOODING PROBLEMS PERSIST...THOUGH LAST NIGHT`S RAINFALL WAS NOT AS GREAT AS EXPECTED AND RIVER LEVELS ARE NOT FORECAST TO BE AS HIGH AS PREVIOUSLY THOUGHT. RIVERS FOR WHICH FLOOD WARNINGS HAVE BEEN ISSUED INCLUDE THE SCIOTO RIVER AT CIRCLEVILLE AND PIKETON...THE GREAT MIAMI RIVER AT SIDNEY AND MIAMITOWN...THE HOCKING RIVER AT ENTERPRISE...AND THE OHIO BRUSH CREEK AT WEST UNION. CONIGLIO LONG TERM /WEDNESDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE TO BUILD SE BECOMING CENTERED OVER OHIO ON WED IN NWRLY FLOW ALOFT. THIS HIGH WL PROVIDE DRY WX AND COLDER TEMPS INTO THURSDAY. ARCTIC AIRMASS VERY DRY AND HAVE KNOCKED DOWN SKY COVER AND GENERALLY PREFER TEMPS AT OR SLIGHTLY COLDER THAN GUID VALUES. IN SPLIT FLO REGIME CONFIDENCE ON PRECIP EVENTS AND TIMING IS NOT HIGH. WITH SFC HIGH PRESSURE OFF TO THE EAST ON THU FLO TO BACK WITH WAA PATTERN DEVELOPING. PRECIP POSSIBLE AS EARLY AS THU...BUT WITH OHIO BTWN SRN AND NRN STREAM MOISTURE...WL MAINTAIN A DRY FCST. HAVE HELD BACK THE INTRODUCTION OF PRECIP UNTIL FRIDAY MORNING. MODELS SHOWING SRN MSTR ADVECTING NEWD AHD OF NRN FRONTAL SYSTEM. AT THIS TIME HAVE ONLY OPTD FOR SLIGHT CHC POPS AND BASED ON TOP DOWN APPROACH EXPECT SNOW NORTH AND RAIN AND SNOW SOUTH. THE AREA LOOKS TO DRY OUT LATER ON FRIDAY NIGHT INTO SAT WITH SFC HI PRESSURE BUILDING BACK IN WITH NWRLY FLOW ALOFT DEVELOPING. AVIATION /18Z-18Z/... FRONT CURRENTLY ANALYZED FROM JUST N OF KCVG AND KILN...TO JUST S OF KLCK. WIDESPREAD -RA CONTINUES TO LIFT NE ACROSS MUCH OF IN/OH WITH A BREAK IN PRECIP APPROACHING KCVG. WIDESPREAD LIFR CIGS ALONG AND N OF THE FRONT WITH SOME MVFR CIGS NOTED S OF THE FRONT AND BEHIND THE PRECIP ACRS KY. THERE IS A CHANCE CIGS COULD LIFT FOR A SHORT PERIOD AT KCVG/KLUK...WITH THE NAM FORECASTING THEM TO STAY JUST S OF THE FRONT FOR A FEW MORE HOURS BEFORE BNDRY SLIDES INTO NRN KENTUCKY AND S OF ALL TERMINALS. 2ND BATCH OF WIDESPREAD RAIN TO COME IN FROM THE SW AROUND 00Z AND LAST THRU 09-12Z...WITH RETURN TO LIFR CIGS/VSBYS. SFC LOW TRACKS INTO NW OH BY 12Z AND BRINGS FRONT EWRD ACROSS THE AREA. THIS WILL SWITCH WINDS TO THE WSW...AND STEEP LAPSE RATES BLO 850 HPA WILL ALLOW FOR 30-40 KT 925 HPA WINDS TO MIX DOWN TO SFC AFTER 12Z. HAWBLITZEL && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ026-034-035-042>046- 051>056-060>065-070>074-077>082-088. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066-073>075- 080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 730 PM EST SUN JAN 14 2007 .SHORT TERM /TONIGHT/... ADJUSTED HOURLY TEMPERATURES DOWN SLIGHTLY TO REFLECT CURRENT CONDITIONS. REST OF FORECAST UNCHANGED. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... FRONT REMAINS DRAPED ACROSS THE AREA. SHOWERS CONTINUE...MAINLY TO THE NORTH OF THE FRONT. A STRONG WAVE OF LOW PRESSURE MOVING UP THE FRONT WILL ENHANCE THE PRECIPITATION AND RESULT IN WIDESPREAD RAINFALL TONIGHT. FLOOD WATCH IS IN EFFECT ALL ZONES. AS THE LOW CONTINUES ON A NORTHEASTERLY TRACK ON MONDAY...IT WILL DRAG THE FRONT EAST OF THE AREA AND ALLOW COLDER AND DRIER AIR TO FILTER IN. TEMPERATURES WILL BE COLD ENOUGH FOR SNOW BY MONDAY NIGHT...AND THOUGH MOISTURE WITH THE LOW WILL BE GONE...THE FLOW BEHIND THE LOW WILL BE CONDUCIVE FOR LAKE ENHANCED SNOW SHOWERS. 850 MB TO LAKE SURFACE TEMPERATURE DIFFERENTIALS WILL BE IMPRESSIVE AT GREATER THAN 15 DEGREES CELSIUS. IN ADDITION...THE RELATIVELY STRONG 850 MB WINDS OF ABOUT 20 KTS AND THE SHALLOW DEPTH OF THE UNSTABLE LAYER WILL ALLOW THE LAKE MOISTURE TO REACH THIS FAR INLAND. WENT WITH A CHANCE OF SNOW SHOWERS MONDAY NIGHT THROUGH TUESDAY AFTERNOON. AS USUAL WITH LAKE EFFECT SITUATIONS IN THE ILN AREA...WE ARE EXPECTING LIGHT SNOW ACCUMULATIONS. SNOW SHOWERS WILL END TUESDAY AFTERNOON WHEN THE AIRMASS BECOMES TO DRY FOR SNOW TO FORM. SKIES WILL BECOME MOSTLY CLEAR TUESDAY NIGHT AS HIGH PRESSURE BUILDS IN. TEMPERATURES ARE VERY TRICKY WITH THE FRONT OVERHEAD. RUC TEMPERATURES APPEARED TO WORK BEST FOR TONIGHT. KEPT CLOSE TO PREVIOUS FORECAST AND BELOW MOS GUIDANCE MONDAY THROUGH TUESDAY. INCREASED TUESDAY NIGHT SLIGHTLY BUT IT MAY STILL BE THE COLDEST NIGHT SO FAR THIS MONTH. DAYTON AND COLUMBUS HAVE BEEN ABOVE NORMAL EVERY DAY SINCE DECEMBER 9...BUT THE STREAK MAY END ON TUESDAY. RIVER FLOODING PROBLEMS PERSIST...THOUGH LAST NIGHT`S RAINFALL WAS NOT AS GREAT AS EXPECTED AND RIVER LEVELS ARE NOT FORECAST TO BE AS HIGH AS PREVIOUSLY THOUGHT. RIVERS FOR WHICH FLOOD WARNINGS HAVE BEEN ISSUED INCLUDE THE SCIOTO RIVER AT CIRCLEVILLE AND PIKETON...THE GREAT MIAMI RIVER AT SIDNEY AND MIAMITOWN...THE HOCKING RIVER AT ENTERPRISE...AND THE OHIO BRUSH CREEK AT WEST UNION. CONIGLIO && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE TO BUILD SE BECOMING CENTERED OVER OHIO ON WED IN NWRLY FLOW ALOFT. THIS HIGH WL PROVIDE DRY WX AND COLDER TEMPS INTO THURSDAY. ARCTIC AIRMASS VERY DRY AND HAVE KNOCKED DOWN SKY COVER AND GENERALLY PREFER TEMPS AT OR SLIGHTLY COLDER THAN GUID VALUES. IN SPLIT FLO REGIME CONFIDENCE ON PRECIP EVENTS AND TIMING IS NOT HIGH. WITH SFC HIGH PRESSURE OFF TO THE EAST ON THU FLO TO BACK WITH WAA PATTERN DEVELOPING. PRECIP POSSIBLE AS EARLY AS THU...BUT WITH OHIO BTWN SRN AND NRN STREAM MOISTURE...WL MAINTAIN A DRY FCST. HAVE HELD BACK THE INTRODUCTION OF PRECIP UNTIL FRIDAY MORNING. MODELS SHOWING SRN MSTR ADVECTING NEWD AHD OF NRN FRONTAL SYSTEM. AT THIS TIME HAVE ONLY OPTD FOR SLIGHT CHC POPS AND BASED ON TOP DOWN APPROACH EXPECT SNOW NORTH AND RAIN AND SNOW SOUTH. THE AREA LOOKS TO DRY OUT LATER ON FRIDAY NIGHT INTO SAT WITH SFC HI PRESSURE BUILDING BACK IN WITH NWRLY FLOW ALOFT DEVELOPING. && .AVIATION /18Z-18Z/... FRONT CURRENTLY ANALYZED FROM JUST N OF KCVG AND KILN...TO JUST S OF KLCK. WIDESPREAD -RA CONTINUES TO LIFT NE ACROSS MUCH OF IN/OH WITH A BREAK IN PRECIP APPROACHING KCVG. WIDESPREAD LIFR CIGS ALONG AND N OF THE FRONT WITH SOME MVFR CIGS NOTED S OF THE FRONT AND BEHIND THE PRECIP ACRS KY. THERE IS A CHANCE CIGS COULD LIFT FOR A SHORT PERIOD AT KCVG/KLUK...WITH THE NAM FORECASTING THEM TO STAY JUST S OF THE FRONT FOR A FEW MORE HOURS BEFORE BNDRY SLIDES INTO NRN KENTUCKY AND S OF ALL TERMINALS. 2ND BATCH OF WIDESPREAD RAIN TO COME IN FROM THE SW AROUND 00Z AND LAST THRU 09-12Z...WITH RETURN TO LIFR CIGS/VSBYS. SFC LOW TRACKS INTO NW OH BY 12Z AND BRINGS FRONT EWRD ACROSS THE AREA. THIS WILL SWITCH WINDS TO THE WSW...AND STEEP LAPSE RATES BLO 850 HPA WILL ALLOW FOR 30-40 KT 925 HPA WINDS TO MIX DOWN TO SFC AFTER 12Z. HAWBLITZEL && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ053>055-060>065- 070>074-077>082-088. FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY MORNING FOR OHZ026-034-035-042>046-051-052-056. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066- 073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 525 PM EST SUN JAN 14 2007 .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... FRONT REMAINS DRAPED ACROSS THE AREA. SHOWERS CONTINUE...MAINLY TO THE NORTH OF THE FRONT. A STRONG WAVE OF LOW PRESSURE MOVING UP THE FRONT WILL ENHANCE THE PRECIPITATION AND RESULT IN WIDESPREAD RAINFALL TONIGHT. FLOOD WATCH IS IN EFFECT ALL ZONES. AS THE LOW CONTINUES ON A NORTHEASTERLY TRACK ON MONDAY...IT WILL DRAG THE FRONT EAST OF THE AREA AND ALLOW COLDER AND DRIER AIR TO FILTER IN. TEMPERATURES WILL BE COLD ENOUGH FOR SNOW BY MONDAY NIGHT...AND THOUGH MOISTURE WITH THE LOW WILL BE GONE...THE FLOW BEHIND THE LOW WILL BE CONDUCIVE FOR LAKE ENHANCED SNOW SHOWERS. 850 MB TO LAKE SURFACE TEMPERATURE DIFFERENTIALS WILL BE IMPRESSIVE AT GREATER THAN 15 DEGREES CELSIUS. IN ADDITION...THE RELATIVELY STRONG 850 MB WINDS OF ABOUT 20 KTS AND THE SHALLOW DEPTH OF THE UNSTABLE LAYER WILL ALLOW THE LAKE MOISTURE TO REACH THIS FAR INLAND. WENT WITH A CHANCE OF SNOW SHOWERS MONDAY NIGHT THROUGH TUESDAY AFTERNOON. AS USUAL WITH LAKE EFFECT SITUATIONS IN THE ILN AREA...WE ARE EXPECTING LIGHT SNOW ACCUMULATIONS. SNOW SHOWERS WILL END TUESDAY AFTERNOON WHEN THE AIRMASS BECOMES TO DRY FOR SNOW TO FORM. SKIES WILL BECOME MOSTLY CLEAR TUESDAY NIGHT AS HIGH PRESSURE BUILDS IN. TEMPERATURES ARE VERY TRICKY WITH THE FRONT OVERHEAD. RUC TEMPERATURES APPEARED TO WORK BEST FOR TONIGHT. KEPT CLOSE TO PREVIOUS FORECAST AND BELOW MOS GUIDANCE MONDAY THROUGH TUESDAY. INCREASED TUESDAY NIGHT SLIGHTLY BUT IT MAY STILL BE THE COLDEST NIGHT SO FAR THIS MONTH. DAYTON AND COLUMBUS HAVE BEEN ABOVE NORMAL EVERY DAY SINCE DECEMBER 9...BUT THE STREAK MAY END ON TUESDAY. RIVER FLOODING PROBLEMS PERSIST...THOUGH LAST NIGHT`S RAINFALL WAS NOT AS GREAT AS EXPECTED AND RIVER LEVELS ARE NOT FORECAST TO BE AS HIGH AS PREVIOUSLY THOUGHT. RIVERS FOR WHICH FLOOD WARNINGS HAVE BEEN ISSUED INCLUDE THE SCIOTO RIVER AT CIRCLEVILLE AND PIKETON...THE GREAT MIAMI RIVER AT SIDNEY AND MIAMITOWN...THE HOCKING RIVER AT ENTERPRISE...AND THE OHIO BRUSH CREEK AT WEST UNION. CONIGLIO && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE TO BUILD SE BECOMING CENTERED OVER OHIO ON WED IN NWRLY FLOW ALOFT. THIS HIGH WL PROVIDE DRY WX AND COLDER TEMPS INTO THURSDAY. ARCTIC AIRMASS VERY DRY AND HAVE KNOCKED DOWN SKY COVER AND GENERALLY PREFER TEMPS AT OR SLIGHTLY COLDER THAN GUID VALUES. IN SPLIT FLO REGIME CONFIDENCE ON PRECIP EVENTS AND TIMING IS NOT HIGH. WITH SFC HIGH PRESSURE OFF TO THE EAST ON THU FLO TO BACK WITH WAA PATTERN DEVELOPING. PRECIP POSSIBLE AS EARLY AS THU...BUT WITH OHIO BTWN SRN AND NRN STREAM MOISTURE...WL MAINTAIN A DRY FCST. HAVE HELD BACK THE INTRODUCTION OF PRECIP UNTIL FRIDAY MORNING. MODELS SHOWING SRN MSTR ADVECTING NEWD AHD OF NRN FRONTAL SYSTEM. AT THIS TIME HAVE ONLY OPTD FOR SLIGHT CHC POPS AND BASED ON TOP DOWN APPROACH EXPECT SNOW NORTH AND RAIN AND SNOW SOUTH. THE AREA LOOKS TO DRY OUT LATER ON FRIDAY NIGHT INTO SAT WITH SFC HI PRESSURE BUILDING BACK IN WITH NWRLY FLOW ALOFT DEVELOPING. && .AVIATION /18Z-18Z/... FRONT CURRENTLY ANALYZED FROM JUST N OF KCVG AND KILN...TO JUST S OF KLCK. WIDESPREAD -RA CONTINUES TO LIFT NE ACROSS MUCH OF IN/OH WITH A BREAK IN PRECIP APPROACHING KCVG. WIDESPREAD LIFR CIGS ALONG AND N OF THE FRONT WITH SOME MVFR CIGS NOTED S OF THE FRONT AND BEHIND THE PRECIP ACRS KY. THERE IS A CHANCE CIGS COULD LIFT FOR A SHORT PERIOD AT KCVG/KLUK...WITH THE NAM FORECASTING THEM TO STAY JUST S OF THE FRONT FOR A FEW MORE HOURS BEFORE BNDRY SLIDES INTO NRN KENTUCKY AND S OF ALL TERMINALS. 2ND BATCH OF WIDESPREAD RAIN TO COME IN FROM THE SW AROUND 00Z AND LAST THRU 09-12Z...WITH RETURN TO LIFR CIGS/VSBYS. SFC LOW TRACKS INTO NW OH BY 12Z AND BRINGS FRONT EWRD ACROSS THE AREA. THIS WILL SWITCH WINDS TO THE WSW...AND STEEP LAPSE RATES BLO 850 HPA WILL ALLOW FOR 30-40 KT 925 HPA WINDS TO MIX DOWN TO SFC AFTER 12Z. HAWBLITZEL && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ053>055-060>065- 070>074-077>082-088. FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH MONDAY MORNING FOR OHZ026-034-035-042>046-051-052-056. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066- 073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1016 PM EST SUN JAN 14 2007 .SHORT TERM /REST OF TONIGHT THROUGH MONDAY/... PREVIOUS FORECAST APPEARS IN VERY GOOD SHAPE THANKS IN PART TO A VERY STAGNANT...SHALLOW COOL AIRMASS ACROSS NRN PENN SEPARATED BY A STATIONARY FRONT FROM UNSEASONABLY MILD AIR IN THE 50S ACROSS SRN PENN. BACKING AND INCREASING 925-800 HPA WINDS WILL HELP TO PUSH MOIST AND EVEN MILDER AIR ALOFT OVER THE REGION LATE TONIGHT. THE MAIN AREA OF STRONGER UVVEL AND QPF WILL OCCUR ACROSS NRN PENN. THIS IS DEPICTED WELL BY THE RATHER STRONG NW/SE GRADIENT OF POPS FOR 0.30 OF AN INCH OF QPF VIA THE SHORT RANGE ENSEMBLES. RAINFALL THROUGH 12Z MONDAY WILL RANGE FROM JUST AROUND ONE TENTH OF AN INCH ACROSS THE LOWER SUSQ VALLEY...TO NEAR 0.75 OF AN INCH ACROSS THE FAR NW ZONES. SREF POINT PLUME DIAGRAMS INDICATE AT LEAST SEVERAL MEMBERS WITH FZRA ACROSS THE KBFD AREA WITH A MEAN ICE ACCUMULATION NEAR 0.20 OF AN INCH. SIMILAR AMOUNTS OF ICE ARE NOTED FURTHER EAST INTO TIOGA COUNTY PENN. 00Z RUC SFC TEMPS ARE IN EXCELLENT AGREEMENT WITH MESO OBS IN THE UPPER 20S TO LOWER 30S IN THE COUNTIES JUST SOUTH OF THE NEW YORK BORDER WHERE OUR CURRENT FZRA ADVISORY RUNS UNTIL 11 AM MONDAY. LIGHT...NEAR SFC WINDS ARE EXPECTED TO SLOWLY VEER FROM THE NE...TO THE SE AND INCREASE TO 5 TO 10 MPH EARLY MONDAY...WHICH MAY ALLOW TEMPS TO RISE TO 33-35F IN MANY LOCATIONS BY 13Z...EXCEPT FOR THE DEEPER VALLEYS. STORM TOTAL QPF BY LATE MONDAY AFTERNOON WILL RANGE FROM AROUND ONE INCH IN THE NORTH...TO JUST UNDER ONE HALF OF AN INCH IN THE FAR SOUTH. SFC COLD FRONT CROSSES THE REGION LATER MONDAY...FOLLOWED BY INCREASING WIND AND A STEADY DROP IN TEMPS TO NEAR NORMAL VALUES BY TUESDAY MORNING. && .PREV DISCUSSION... /ISSUED 335 PM EST SUN JAN 14 2007/ SHORT TERM /TONIGHT THROUGH MONDAY/... QUASI STATIONARY FRONT REMAINS DRAPED ACROSS CENTRAL PA THIS AFTERNOON WITH WEAK WAVES OF LOW PRESSURE RIPPLING EASTWARD ALONG THE FRONT. MAIN SURFACE LOW TAKING SHAPE OVER SOUTHERN ARKANSAS THIS AFTERNOON AND EVENING WL TRACK NORTHEASTWARD OVERNIGHT BRINGING A SURGE OF MOISTURE AND MOSTLY RAINFALL TO CENTRAL PA. SREF PLUMES CONTINUE TO INDICATE FZRA POTENTIAL WELL TO THE NORTH OF I-80 WHERE FZRA ADVISORY WILL BE CONTINUED FROM 7PM THIS EVENING THROUGH 11 AM MONDAY. QPF ISSUES: SREF PLUMES ALSO SHOW MEDIAN VALUES OF .9 TO 1.2 THROUGHOUT CENTRAL AND NORTHERN SECTIONS OF CENTRAL PA WITH LESSER AMOUNTS TO THE SOUTH. THESE AMOUNTS NOT ENOUGH TO CAUSE HEADLINABLE PROBLEMS ON AREA RIVERS...ALTHOUGH WILLIAMSPORT IS STILL FORECAST TO REACH CAUTION STAGE (NOW EXPECTED TOMORROW AFTERNOON). SFC LOW WILL TRACK FROM KCAK NORTHEASTWARD TO KELM AND KBGM MONDAY AFTERNOON EVENTUALLY BRINGING MUCH COLDER (AND MORE SEASONABLE) BACK INTO PA LATER MONDAY NIGHT AND TUESDAY...SIGNALING A PATTERN CHANGE TO MORE SEASONABLE CONDITIONS THAT APPEARS WILL BE WITH US FOR THE NEXT 2 WEEKS. LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... COLD FRONT WILL CROSS THE REGION MONDAY NIGHT AND THE FIRST HALF OF TUESDAY BRINGING NOTICEABLE CHANGES TO THE WEATHER AS WE RETURN TO MORE SEASONABLE CONDITIONS. AS COLDER AND DRIER AIR PUSH IN BEHIND THE FRONT...TUESDAY WILL BE A BREEZY DAY. TEMPS WILL BE FALLING THROUGH THE DAY AND WITH VERY MILD CONDITIONS RECENTLY IT WILL FEEL QUITE CHILLY. WINDS LINE UP UNIDIRECTIONALLY ACROSS THE LAKES TUE AFTERNOON AND LAKE EFFECT SNOW SHOWERS WILL DEVELOP BY TUE NIGHT AND WILL ONLY LAST INTO WED BEFORE FLOW BREAKS DOWN AS SURFACE HIGH MOVES IN. TEMPS MODERATE A BIT FOR LATE WEEK BEFORE CLIPPER SLIPS THROUGH LATER THU BRINGING A CHANCE FOR SNOW SHOWERS TO THE NORTH. TROUGH APPROACHES FROM THE NW FRI INTO SAT...AND CENTER OF SURFACE LOW WILL MOVE ACROSS S CANADA BRINGING NW FLOW TO THE REGION ALONG WITH ANOTHER ROUND OF SNOW SHOWERS UNDER BASE OF TROUGH. AVIATION /21Z-18Z/... IFR/LIFR CONDS WILL PERSIST OVR ALL OF CENTRAL PA THROUGH MONDAY MORNING...AS A STATIONARY FRONT IS DRAPED ALONG THE SOUTHERN TIER OF THE STATE...AND MAIN SFC LOW TRACKS FROM AR THIS AFTERNOON TO N CENTRAL PA MIDDAY MONDAY. RELATIVELY COOL AIR AT THE SFC WILL BE OVERRUN BY A WARM SOUTHWEST FLOW ALOFT...CREATING PERIODS OF RAIN...ALONG WITH LOW CLDS AND FOG NORTH OF THE FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR PAZ004>006- 037-041-042. && $$ SHORT TERM...LAMBERT pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 828 PM CST SUN JAN 14 2007 .UPDATE... UPDATED FORECAST AND GRIDS TO LOWER OVERNIGHT LOW SEVERAL DEGREES IN MOST AREAS. TEMPERATURES DROPPED TO -7F OR MORE IN THE NORTHERN COUNTIES AND EXPECT FURTHER FALLS BEFORE MORNING. THIS ALSO DROPS EXPECTED WIND CHILL VALUES BUT STILL IN THE SAME GENERAL CATEGORY...COLD. WILL NEED TO KEEP CLOSE EYE ON SOUTHEAST PART OF THIS AREA. AS COLD PUSHES FARTHER SOUTH IT IS ALSO LIMITING NORTHERN EXTENT OF PRECIPITATION AREA. WILL STAY WITH WINTER WEATHER ADVISORY AT THIS TIME FOR THE COMBINATION OF LOW WIND CHILL AND SNOW OR BLOWING SNOW. LATEST WSR-88D DEPICTING AREA OF INCREASING RETURNS OVER THIS AREA AT THIS TIME. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT NUMBER OF ISSUES TO DEAL WITH OVER THE NEXT 24 HOURS...MOST NOTABLY THE SNOWFALL EXPECTED ACROSS THE SE CORNER OF THE CWA...AND WIND CHILLS. STEADY AREA OF PRECIPITATION HAS BEEN WORKING ITS WAY NORTHWARD ALL AFTERNOON. FINALLY SEEING SOME REPORTS OF SNOW IN KSFD AND KFSD. AS THE UPPER LOW CURRENTLY OVER NE COLORADO...CONTINUES TO LIFT NE AREA OF SNOW SHOULD ALSO CONTINUE TO PUSH NORTHEASTWARD. HOWEVER EXACTLY HOW FAR NORTH WILL BE TRICKY...AS LARGE AMOUNT OF COLD DRY AIR PUSHING SOUTH FROM CANADA WILL AID IN HEAVIEST PRECIPITATION AMOUNTS STAYING TO THE SOUTH AND EAST OF THE CWA. NAM/GFS/RUC ALL IN AGREEMENT THAT SOME PRECIP SHOULD MAKE IT INTO AT LEAST THE EASTERN CWA THIS EVENING INTO THE OVERNIGHT HOURS. BEST OMEGA ADVERTISED OVER THAT AREA FROM 00Z TO 06Z TONIGHT. ALSO BEST LIFT ASSOCIATED WITH THE Q-VECTOR FIELD STAYS TO THE SOUTH AND EAST OF THE AREA...WITH SOME SLIGHT DIVERGENCE NOTED THIS EVENING IN THE KATY AREA. AS THE SNOW IN CENTRAL NEBRASKA PUSHES NORTHWARD SHOULD SEE SOME PUSH THROUGH LYMAN COUNTY INTO BUFFALO COUNTY...WITH THE REMAINDER OF CENTRAL SD REMAINING FAIRLY DRY FOR TONIGHT AS THE PRECIPITATION AREA SHIFTS EASTWARD WITH THE UPPER LOW LIFTING OUT. WITH SOME WIND EXPECTED 15 TO 20 MPH ACROSS THE EASTERN CWA...COULD END UP WITH SOME BLOWING SNOW. ALSO WITH THE COLD AIR IN PLACE...AND THE WIND...WILL HAVE VERY COLD WIND CHILLS AS WELL. THEREFORE ACROSS THE EXTREME SE CORNER OF THE CWA HAVE GONE WITH A WINTER WX ADVISORY FOR THE COMBINATION OF SNOW...PATCHY BLOWING SNOW...AND WIND CHILLS. AS FOR THE REMAINDER OF THE CWA...HAVE A WIND CHILL ADVISORY OUT FOR NORTHEAST SOUTH DAKOTA...AND WEST CENTRAL MINNESOTA FOR TONIGHT INTO MONDAY MORNING. WINDS SHOULD FALL OFF ENOUGH ACROSS NORTH CENTRAL SD...SO WILL ONLY KEEP THE WIND CHILL ADVISORY OUT THROUGH 00Z THIS EVENING. FOCUS THEN SHIFTS TO WEAK WAVE DROPPING SOUTHEAST LATER TONIGHT OUT OF NE MONTANA. WEAK LIFT AND SOME MOISTURE ACROSS THE AREA WITH THIS WAVE...SO HAVE MENTIONED SOME FLURRIES SPREADING ACROSS THE AREA BY LATE TONIGHT INTO EARLY MONDAY. MONDAY NIGHT WILL REMAIN COLD WITH CLEAR SKIES...AND ARCTIC HIGH PRESSURE ACROSS THE EAST. EXPECT WINDS TO BE BELOW 10 MPH...BUT WILL HAVE TO MONITOR FOR POSSIBILITY OF THE COLD WIND CHILLS AGAIN. OTHERWISE HAVE WAA INTO THE AREA TUESDAY INTO WEDNESDAY...WITH SOME RECOVERY IN TEMPS EXPECTED. DO HAVE ANOTHER SHORTWAVE SLATED TO PUSH NE THROUGH THE CWA LATE WEDNESDAY NIGHT...AND HAVE ADDED IN A MENTION OF SNOW WITH THIS SYSTEM. .LONG TERM...THURSDAY THROUGH SUNDAY NO BIG CHANGES MADE TO PREVIOUS FORECAST. ONLY CONCERN IN LONG TERM PORTION OF THE FORECAST IS HOW THE CUT OFF LOW OVER THE SOUTHWESTERN UNITED STATES WILL EITHER KEEP A SPLIT FLOW OVER THE NORTHERN PLAINS OR IF THE LOW WILL EVOLVE INTO A MOVING WAVE IN THE FLOW. HPC IS FAVORING A NON-PROGRESSIVE SOLUTION WHICH KEEPS THIS AREA IN NORTHWESTERLY FLOW THROUGH THE PERIOD. THIS WILL MAKE THE CURRENT DRY FORECAST HOLD THROUGH SATURDAY. SOME MODIFICATIONS TO COLD AIR MASS ARE IN STORE BY LATE THIS WEEK AS FRONT THAT COMES THOUGH AT THE START OF THE EXTENDED PERIOD IS SUPPORTED BY A MORE MARITIME-INFLUENCED AIRMASS AND THUS EXPECT TEMPERATURES TO RETURN TO NEAR NORMAL BY LATE THIS WEEK. A RATHER COLD HIGH PRESSURE LOOKS TO SLIDE EAST OF THIS AREA BY SATURDAY...WITH COLDEST AIR STAYING TO THE EAST OF THIS HIGH. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BROWN-CLARK-DAY-EDMUNDS-FAULK-MARSHALL-MCPHERSON-ROBERTS-SPINK. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BUFFALO-HAND-HYDE. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CODINGTON- DEUEL-GRANT-HAMLIN. MN...WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BIG STONE- TRAVERSE. && $$ KEEFE/ALBRECHT/HARDING sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 551 PM CST SUN JAN 14 2007 .UPDATE... UPDATED FORECAST AND GRIDS TO CANCEL WINF CHILL ADVISORY IN PARTS OF NORTHCENTRAL SOUTH DAKOTA. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT NUMBER OF ISSUES TO DEAL WITH OVER THE NEXT 24 HOURS...MOST NOTABLY THE SNOWFALL EXPECTED ACROSS THE SE CORNER OF THE CWA...AND WIND CHILLS. STEADY AREA OF PRECIPITATION HAS BEEN WORKING ITS WAY NORTHWARD ALL AFTERNOON. FINALLY SEEING SOME REPORTS OF SNOW IN KSFD AND KFSD. AS THE UPPER LOW CURRENTLY OVER NE COLORADO...CONTINUES TO LIFT NE AREA OF SNOW SHOULD ALSO CONTINUE TO PUSH NORTHEASTWARD. HOWEVER EXACTLY HOW FAR NORTH WILL BE TRICKY...AS LARGE AMOUNT OF COLD DRY AIR PUSHING SOUTH FROM CANADA WILL AID IN HEAVIEST PRECIPITATION AMOUNTS STAYING TO THE SOUTH AND EAST OF THE CWA. NAM/GFS/RUC ALL IN AGREEMENT THAT SOME PRECIP SHOULD MAKE IT INTO AT LEAST THE EASTERN CWA THIS EVENING INTO THE OVERNIGHT HOURS. BEST OMEGA ADVERTISED OVER THAT AREA FROM 00Z TO 06Z TONIGHT. ALSO BEST LIFT ASSOCIATED WITH THE Q-VECTOR FIELD STAYS TO THE SOUTH AND EAST OF THE AREA...WITH SOME SLIGHT DIVERGENCE NOTED THIS EVENING IN THE KATY AREA. AS THE SNOW IN CENTRAL NEBRASKA PUSHES NORTHWARD SHOULD SEE SOME PUSH THROUGH LYMAN COUNTY INTO BUFFALO COUNTY...WITH THE REMAINDER OF CENTRAL SD REMAINING FAIRLY DRY FOR TONIGHT AS THE PRECIPITATION AREA SHIFTS EASTWARD WITH THE UPPER LOW LIFTING OUT. WITH SOME WIND EXPECTED 15 TO 20 MPH ACROSS THE EASTERN CWA...COULD END UP WITH SOME BLOWING SNOW. ALSO WITH THE COLD AIR IN PLACE...AND THE WIND...WILL HAVE VERY COLD WIND CHILLS AS WELL. THEREFORE ACROSS THE EXTREME SE CORNER OF THE CWA HAVE GONE WITH A WINTER WX ADVISORY FOR THE COMBINATION OF SNOW...PATCHY BLOWING SNOW...AND WIND CHILLS. AS FOR THE REMAINDER OF THE CWA...HAVE A WIND CHILL ADVISORY OUT FOR NORTHEAST SOUTH DAKOTA...AND WEST CENTRAL MINNESOTA FOR TONIGHT INTO MONDAY MORNING. WINDS SHOULD FALL OFF ENOUGH ACROSS NORTH CENTRAL SD...SO WILL ONLY KEEP THE WIND CHILL ADVISORY OUT THROUGH 00Z THIS EVENING. FOCUS THEN SHIFTS TO WEAK WAVE DROPPING SOUTHEAST LATER TONIGHT OUT OF NE MONTANA. WEAK LIFT AND SOME MOISTURE ACROSS THE AREA WITH THIS WAVE...SO HAVE MENTIONED SOME FLURRIES SPREADING ACROSS THE AREA BY LATE TONIGHT INTO EARLY MONDAY. MONDAY NIGHT WILL REMAIN COLD WITH CLEAR SKIES...AND ARCTIC HIGH PRESSURE ACROSS THE EAST. EXPECT WINDS TO BE BELOW 10 MPH...BUT WILL HAVE TO MONITOR FOR POSSIBILITY OF THE COLD WIND CHILLS AGAIN. OTHERWISE HAVE WAA INTO THE AREA TUESDAY INTO WEDNESDAY...WITH SOME RECOVERY IN TEMPS EXPECTED. DO HAVE ANOTHER SHORTWAVE SLATED TO PUSH NE THROUGH THE CWA LATE WEDNESDAY NIGHT...AND HAVE ADDED IN A MENTION OF SNOW WITH THIS SYSTEM. .LONG TERM...THURSDAY THROUGH SUNDAY NO BIG CHANGES MADE TO PREVIOUS FORECAST. ONLY CONCERN IN LONG TERM PORTION OF THE FORECAST IS HOW THE CUT OFF LOW OVER THE SOUTHWESTERN UNITED STATES WILL EITHER KEEP A SPLIT FLOW OVER THE NORTHERN PLAINS OR IF THE LOW WILL EVOLVE INTO A MOVING WAVE IN THE FLOW. HPC IS FAVORING A NON-PROGRESSIVE SOLUTION WHICH KEEPS THIS AREA IN NORTHWESTERLY FLOW THROUGH THE PERIOD. THIS WILL MAKE THE CURRENT DRY FORECAST HOLD THROUGH SATURDAY. SOME MODIFICATIONS TO COLD AIR MASS ARE IN STORE BY LATE THIS WEEK AS FRONT THAT COMES THOUGH AT THE START OF THE EXTENDED PERIOD IS SUPPORTED BY A MORE MARITIME-INFLUENCED AIRMASS AND THUS EXPECT TEMPERATURES TO RETURN TO NEAR NORMAL BY LATE THIS WEEK. A RATHER COLD HIGH PRESSURE LOOKS TO SLIDE EAST OF THIS AREA BY SATURDAY...WITH COLDEST AIR STAYING TO THE EAST OF THIS HIGH. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BROWN-CLARK-DAY-EDMUNDS-FAULK-MARSHALL-MCPHERSON-ROBERTS-SPINK. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BUFFALO-HAND-HYDE. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CODINGTON- DEUEL-GRANT-HAMLIN. MN...WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BIG STONE- TRAVERSE. && $$ KEEFE/ALBRECHT/HARDING sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 323 PM CST SUN JAN 14 2007 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT NUMBER OF ISSUES TO DEAL WITH OVER THE NEXT 24 HOURS...MOST NOTABLY THE SNOWFALL EXPECTED ACROSS THE SE CORNER OF THE CWA...AND WIND CHILLS. STEADY AREA OF PRECIPITATION HAS BEEN WORKING ITS WAY NORTHWARD ALL AFTERNOON. FINALLY SEEING SOME REPORTS OF SNOW IN KSFD AND KFSD. AS THE UPPER LOW CURRENTLY OVER NE COLORADO...CONTINUES TO LIFT NE AREA OF SNOW SHOULD ALSO CONTINUE TO PUSH NORTHEASTWARD. HOWEVER EXACTLY HOW FAR NORTH WILL BE TRICKY...AS LARGE AMOUNT OF COLD DRY AIR PUSHING SOUTH FROM CANADA WILL AID IN HEAVIEST PRECIPITATION AMOUNTS STAYING TO THE SOUTH AND EAST OF THE CWA. NAM/GFS/RUC ALL IN AGREEMENT THAT SOME PRECIP SHOULD MAKE IT INTO AT LEAST THE EASTERN CWA THIS EVENING INTO THE OVERNIGHT HOURS. BEST OMEGA ADVERTISED OVER THAT AREA FROM 00Z TO 06Z TONIGHT. ALSO BEST LIFT ASSOCIATED WITH THE Q-VECTOR FIELD STAYS TO THE SOUTH AND EAST OF THE AREA...WITH SOME SLIGHT DIVERGENCE NOTED THIS EVENING IN THE KATY AREA. AS THE SNOW IN CENTRAL NEBRASKA PUSHES NORTHWARD SHOULD SEE SOME PUSH THROUGH LYMAN COUNTY INTO BUFFALO COUNTY...WITH THE REMAINDER OF CENTRAL SD REMAINING FAIRLY DRY FOR TONIGHT AS THE PRECIPITATION AREA SHIFTS EASTWARD WITH THE UPPER LOW LIFTING OUT. WITH SOME WIND EXPECTED 15 TO 20 MPH ACROSS THE EASTERN CWA...COULD END UP WITH SOME BLOWING SNOW. ALSO WITH THE COLD AIR IN PLACE...AND THE WIND...WILL HAVE VERY COLD WIND CHILLS AS WELL. THEREFORE ACROSS THE EXTREME SE CORNER OF THE CWA HAVE GONE WITH A WINTER WX ADVISORY FOR THE COMBINATION OF SNOW...PATCHY BLOWING SNOW...AND WIND CHILLS. AS FOR THE REMAINDER OF THE CWA...HAVE A WIND CHILL ADVISORY OUT FOR NORTHEAST SOUTH DAKOTA...AND WEST CENTRAL MINNESOTA FOR TONIGHT INTO MONDAY MORNING. WINDS SHOULD FALL OFF ENOUGH ACROSS NORTH CENTRAL SD...SO WILL ONLY KEEP THE WIND CHILL ADVISORY OUT THROUGH 00Z THIS EVENING. FOCUS THEN SHIFTS TO WEAK WAVE DROPPING SOUTHEAST LATER TONIGHT OUT OF NE MONTANA. WEAK LIFT AND SOME MOISTURE ACROSS THE AREA WITH THIS WAVE...SO HAVE MENTIONED SOME FLURRIES SPREADING ACROSS THE AREA BY LATE TONIGHT INTO EARLY MONDAY. MONDAY NIGHT WILL REMAIN COLD WITH CLEAR SKIES...AND ARCTIC HIGH PRESSURE ACROSS THE EAST. EXPECT WINDS TO BE BELOW 10 MPH...BUT WILL HAVE TO MONITOR FOR POSSIBILITY OF THE COLD WIND CHILLS AGAIN. OTHERWISE HAVE WAA INTO THE AREA TUESDAY INTO WEDNESDAY...WITH SOME RECOVERY IN TEMPS EXPECTED. DO HAVE ANOTHER SHORTWAVE SLATED TO PUSH NE THROUGH THE CWA LATE WEDNESDAY NIGHT...AND HAVE ADDED IN A MENTION OF SNOW WITH THIS SYSTEM. .LONG TERM...THURSDAY THROUGH SUNDAY NO BIG CHANGES MADE TO PREVIOUS FORECAST. ONLY CONCERN IN LONG TERM PORTION OF THE FORECAST IS HOW THE CUT OFF LOW OVER THE SOUTHWESTERN UNITED STATES WILL EITHER KEEP A SPLIT FLOW OVER THE NORTHERN PLAINS OR IF THE LOW WILL EVOLVE INTO A MOVING WAVE IN THE FLOW. HPC IS FAVORING A NON-PROGRESSIVE SOLUTION WHICH KEEPS THIS AREA IN NORTHWESTERLY FLOW THROUGH THE PERIOD. THIS WILL MAKE THE CURRENT DRY FORECAST HOLD THROUGH SATURDAY. SOME MODIFICATIONS TO COLD AIR MASS ARE IN STORE BY LATE THIS WEEK AS FRONT THAT COMES THOUGH AT THE START OF THE EXTENDED PERIOD IS SUPPORTED BY A MORE MARITIME-INFLUENCED AIRMASS AND THUS EXPECT TEMPERATURES TO RETURN TO NEAR NORMAL BY LATE THIS WEEK. A RATHER COLD HIGH PRESSURE LOOKS TO SLIDE EAST OF THIS AREA BY SATURDAY...WITH COLDEST AIR STAYING TO THE EAST OF THIS HIGH. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...WIND CHILL ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR CAMPBELL-CORSON-DEWEY-POTTER-WALWORTH. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BROWN-CLARK-DAY- EDMUNDS-FAULK-MARSHALL-MCPHERSON-ROBERTS-SPINK. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BUFFALO-HAND-HYDE. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CODINGTON- DEUEL-GRANT-HAMLIN. MN...WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR BIG STONE- TRAVERSE. && $$ ALBRECHT/HARDING sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 225 PM CST MON JAN 15 2007 .DISCUSSION...SURFACE OBS FROM AROUND THE REGION SHOW THE GOOD CAA CONTINUING ON THE NORTH-NORTHWEST SURFACE WINDS BLOWING AT 15 TO 25 KNOTS ACROSS THE REGION. CURRENT TEMPS RANGE FROM 37 AT BOTH HEBBRONVILLE AND FALFURRIAS TO 45 DEGREES AT WESLACO AND BAYVIEW. GFS AND ETA FORECAST SOUNDINGS BOTH SHOW TEMPS DROPPING BELOW FREEZING FROM AROUND 850 TO 975 MB BY 18Z TUESDAY WHICH WILL PROVIDE A PRETTY SUBSTANTIAL FREEZING LAYER. ANY SIGNIFICANT RAIN THAT FALLS THROUGH THIS LAYER HAS THE POTENTIAL FOR SLEET FORMATION LATER TONIGHT INTO TUESDAY. HOWEVER...SOME MAJOR DIFFENCES SHOW UP CONCERNING PROGGED MOISTURE LEVELS NEAR THIS COLD LAYER. THE ETA SHOWS PRETTY SIGNIFICANT DRYING OCCURRING THROUGH 18Z TUES IN COMPARISON TO THE GFS WHICH HAS A MORE SATURATED FREEZING LAYER ALOFT. THIS IS THE BIG FLY IN THE OINTMENT. IF THIS ELEVATED COLD LAYER DOES DRY OUT SOMEWHAT...THIS WILL IN TURN DIMINISH POPS AND ACCORDINGLY...WILL DIMINISH THE SLEET CHCS. HOWEVER...AM HESITANT TO REDUCE POPS VERY MUCH DURING THE OVERNIGHT PERIOD DUE TO A COUPLE OF REASONS. FIRST...THE GFS CONTINUES TO ADVERTISE SOME POTENTIAL FOR SOME WEAK COASTAL SURFACE TROFFING INTO TOMORROW WHICH WOULD HELP WITH LOW LEVEL CONVERGENCE ACROSS THE EASTERN SECTIONS. SECOND... THE GFS AND RUC GUIDANCE SHOW SOME BETTER 500 MB PVA SKIRTING THE BRO CWA JUST TO THE NORTH AND WEST WHICH MAY ALSO ENHANCE THE LIFT SOMEWHAT ALLOWING A RAIN/SLEET MIXTURE TO BEGIN LATER TONIGHT. THE NAM AND GFS SHOW SOME BETTER AGREEMENT CONCERNING POPS AFTER TONIGHT AS THE NAM PICKS UP ON SOME INVERTED COASTAL SURFACE TROFFING TUESDAY INTO WEDNESDAY WHICH ALSO HELPS MAINTAIN SOME CHC POPS OUT INTO PERIODS 3 AND 4. THE AIRMASS BEGINS TO MODERATE ON WED AS THE CAA WEAKENS AND WARMER SOUTHWESTERLY FLOW ALOFT TRIES TO BUILD DOWN TO THE SURFACE FINALLY ERODING AWAY THE SUB-FREEZING LAYER AROUND 18Z WED. HOWEVER...ENOUGH MOISTURE LINGERS AROUND THE AREA AND THE LOW LEVEL INVERSION HOLDS ON THROUGH THE END OF THE WEEK TO MAINTAIN THE CLOUD COVER...FAIRLY COOL TEMPS AND SLGT CHC/CHC POPS INTO NEXT WEEKEND. FOR TEMPS WILL GO CLOSER TO THE COOLER MET GUIDANCE FOR BOTH HRL AND BRO. FURTHER WEST...THE MAV GUIDANCE IS COOLER THAN THE MET AND WILL GO CLOSER TO THESE FOR MFE TEMPS. ALSO...WILL UPGRADE THE CURRENT FREEZE WATCH TO A WARNING FOR THE NORTHERN FOUR COUNTIES AND WILL ISSUE A WINTER WX ADVISORY FOR MOST OF THE BRO CWA TO ACCOUNT FOR ANY RAIN/SLEET MIXTURE OVERNIGHT INTO TUES. && .MARINE...AT 1PM BUOY020 REPORTED NORTH WINDS AT 27G33KTS WHILE BUOY019 REPORTED SEAS OF 8.5 FEET. LIGHT RAIN BEHIND THE COLD FRONT WILL CONTINUE TO OVERSPREAD THE REGION THROUGH THE NEXT 24 HOURS. WINDS WILL CONTINUE TO RUSH IN FROM THE NORTHWEST AROUND 30 KTS WITH GUSTS ABOVE 35 KNOTS POSSIBLE. AS A RESULT...GALE WARNINGS ARE IN EFFECT FOR THE COASTAL WATERS. WINDS WILL REMAIN BELOW 35 KNOTS ALONG THE LAGUNA MADRE...SO ONLY SCA WILL BE NEEDED. THESE CONDITIONS WILL REMAIN FOR AT LEAST THE NEXT 48 HOURS AS COLD AIR CONTINUES TO POUR IN FROM THE NORTH UNDERNEATH SOUTHWEST FLOW ALOFT. && .AVIATION...CONDITIONS WILL REMAIN BORDERLINE IFR THROUGH 24 HOURS AS LOW CLOUD DECK HOVERS AROUND 1KFT. EXPECT GUSTY NORTH WINDS OF 20 TO 25KTS WITH HIGHER GUSTS TO CONTINUE AS WELL. LIGHT RAIN AND DRIZZLE WILL CONTINUE WITH ICING CONDITIONS POSSIBLE JUST ABOVE THE SURFACE. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 38 42 37 48 43 / 60 60 50 30 30 BROWNSVILLE 37 42 36 48 43 / 60 60 50 30 30 HARLINGEN 36 40 35 48 42 / 60 60 50 30 30 MCALLEN 35 39 34 46 40 / 60 60 50 30 30 RIO GRANDE CITY 34 38 32 45 38 / 50 60 50 30 30 SOUTH PADRE ISLAND 41 44 40 48 45 / 60 60 50 30 30 && .BRO WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FOR TXZ248>253 FROM MIDNIGHT TONIGHT THROUGH 6 PM TUESDAY FREEZE WARNING FOR TXZ248>251 FROM MIDNIGHT TONIGHT THROUGH 7 AM TUESDAY. GALE WARNING FOR GMZ150-155-170-175 IN EFFECT THROUGH MIDNIGHT WEDNESDAY. SCA FOR GMZ130-132-135 15Z IN EFFECT THROUGH MIDNIGHT WEDNESDAY. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO SYNOPTIC/GRIDS...60 MARINE/AVIATION...64 MESO...VEGA tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1130 AM CST MON JAN 15 2007 .AVIATION... BL MSTR STILL PREVELANT WITH SUBLIMATION/EVAPORATION OCCURING IN SUB-FREEZING AIRMASS. ALSO AS CWSU NOTES...CAA/LOW-LVL THICKNESS PACKING TO BE STRONG...ALONG WITH UNIDIRECTIONAL NNW FLOW IN LOWER 5 KFT OR SO. THUS...EXPECT PREVALING MVFR CIGS/TEMPO SCT VFR D/FW TAF SITES WITH GSTY N/NW WNDS 15-20 KTS...GSTS TO 25 KTS THRU 00Z TUES...BEFORE DECOUPLING TAKES HOLD. EVEN SO...CAA TO HOLD N WNDS ARND 10 KTS INTO EARLY TUES...AS MVFR CIGS DISSIPATE WITH VFR CIGS (CS/AS) TAKE HOLD. KACT...NOT MUCH DIFFERENCE...EXCEPT A LITTLE DELAYED ON MVFR CIGS. && .PREV DISCUSSION... /ISSUED 1056 AM CST MON JAN 15 2007/ UPDATE... PROGRESSION OF WINTRY MIX OF PRECIPITATION...AND SUBSEQUENT DRYING/ SUBSIDENCE BEHIND THE BAND HAS BEEN MORE PROGRESSIVE THAN EARLIER EXPECTED AND MORE IN LINE WITH THE NAM/RUC MODELS...ESPECIALLY THEIR NEW 12Z RUNS...AS BEST MID LVL FRONTOGENESIS HAS SHIFTED OVER SE CWA. EXPECT DISTURBANCES IN SUBTROPICAL JET BRANCH TO CONTINUE TO GRAZE FAR SE COUNTIES THROUGH AT LEAST 00Z TUES. ALSO...DEEPER ARCTIC AIRMASS IS NOW ARRIVING PER LATEST VWP AND AREA SOUNDINGS (THOUGH 12Z FWD WAS A NO GO). DESPITE SUNSHINE OVER NW 1/2 OF N TX...DEEP/DENSE AIRMASS THROUGH 5 KFT WON`T ALLOW MUCH IN THE WAY OF WARMING...THOUGH INSOLATION AND TRAFFIC SHOULD HELP IN THE SUBLIMATION AFFECTS OF EARLIER ICE ACCUMULATIONS. AS A RESULT...ICE STORM WARNING HAS BEEN CANCELED OVER THE NW 1/2... WITH THE FREEZING RAIN ADVISORY CANCELED OVER NE COUNTIES. FREEZING RAIN ADVISORY CONTS OVER SE COUNTIES (SE OF A LAMPASAS...WACO... CORSICANA...CANTON LINE). SEE ADVISORY LINE BELOW. ADVISORY/WARNING INFORMATION ALREADY SENT VIA FTWWSWFWD. FORECASTS AND HAZARDOUS WX OUTLOOK UPDATED FOR CURRENT TRENDS AS WELL. WE WILL BE ISSUING AN SPS FOR CONTINUED ICY ROADS/HIGHWAYS SHORTLY... NAMELY FOR BRIDGES AND OVERPASSES AND SECONDARY ROADS. PREV DISCUSSION... /ISSUED 541 AM CST MON JAN 15 2007/ 12Z AVIATION UPDATE...BACK EDGE OF THE PRECIPITATION IS MOVING THROUGH THE METROPLEX NOW...BUT SEVERAL OB SITES STILL REPORTING SOME LIGHT FREEZING RAIN AND SLEET. SATELLITE IMAGERY SHOWS SOME CLEARING TO THE WEST...BUT STRONG SW FLOW ALOFT MAY KEEP SOME HIGH CLOUDINESS AROUND FOR A WHILE. WILL START OUT WITH IMPROVING CONDS AND ONLY KEEP A TEMPO GROUP IN UNTIL 14Z TO COVER LINGERING SLEET SHOWERS. CIGS IMPROVE TO VFR BY MID MORNING BUT GUSTY NORTHERLY WINDS WILL PERSIST THROUGH THE EARLY AFTERNOON. EXPECT VFR CIGS/VIS THROUGH THE END OF THE PERIOD. 91/DUNN PREV DISCUSSION... /ISSUED 409 AM CST MON JAN 15 2007/ MOST OF THE WINTER PRECIPITATION WILL SLOWLY COME TO AN END TODAY...AT LEAST IN THE ICE STORM WARNING AREA. HOWEVER...LIGHT PRECIP WILL CONTINUE INTO THE EVENING IN THE FAR SOUTH. WITH THE PRECIP SLOW TO END...WE WILL EXTEND THE ICE STORM WARNING UNTIL NOON TODAY AND CONTINUE THE FREEZING RAIN ADVISORY IN THE EAST. THE ADVISORY MAY HAVE TO BE ADJUSTED FOR TONIGHT BUT CONSIDERING THE SLOW MOVEMENT AND OTHER FACTORS...THIS WILL BE BETTER HANDLED BY THE DAY CREW. ADDITIONAL ICE ACCUMULATIONS WILL BE LESS THAN ONE QUARTER OF AN INCH IN THE WARNING AREA. MOST OF THE AREA IS WELL BELOW FREEZING THIS MORNING AND WITH OVERNIGHT RAIN...ICE HAS BECOME MORE OF A PROBLEM...ESPECIALLY ON ELEVATED SURFACES. THE MORNING COMMUTE WILL BE EXTREMELY DIFFICULT FOR MANY. WITH CONDITIONS IMPROVING LATER THIS MORNING AS THE PRECIP MOVES OUT...HOPEFULLY MANY WILL BE ABLE TO DELAY THEIR TRAVELS A FEW HOURS. STILL...WHERE THE TEMPERATURE HAS BEEN BELOW FREEZING FOR THE LAST DAY OR SO...ICE HAS BEGUN TO ACCUMULATE ON SURFACES SUCH AS SIDEWALKS...MAKING EVEN WALKING DIFFICULT AT TIMES. THIS SHOULD ALSO IMPROVE AFTER THE PRECIP ENDS WITH GUSTY NORTH WINDS DRYING SURFACES. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THIS WEEK...IN FACT RATHER COLD THE NEXT FEW DAYS AS NORTH WINDS AND CLOUDINESS PERSIST. LIGHT PRECIP WILL PERSIST TONIGHT IN THE SOUTH BUT DO NOT ANTICIPATE SIGNIFICANT ACCUMULATIONS...AND TUESDAY WILL BE DRY. HOWEVER...ON WEDNESDAY WE WILL SEE ANOTHER UPPER LEVEL DISTURBANCE MOVE ACROSS THE AREA. WITH MORNING SURFACE LOWS WELL BELOW FREEZING...ALONG WITH THE COLUMN OF AIR ABOVE...WE COULD SEE SOME LIGHT SNOW IN THE MORNING...CHANGING MORE TO RAIN BY AFTERNOON. TEMPERATURES SHOULD SLOWLY WARM TO MORE NORMAL READINGS AFTER WEDNESDAY...WITH A CHANCE FOR RAIN BY THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 29 24 35 23 35 / 10 0 10 10 20 WACO, TX 30 25 34 25 35 / 40 10 10 10 20 PARIS, TX 29 21 34 20 36 / 10 0 10 10 20 DENTON, TX 29 20 35 22 35 / 10 0 10 10 20 MCKINNEY, TX 29 22 34 22 36 / 10 0 10 10 20 DALLAS, TX 29 25 35 23 38 / 10 0 10 10 20 TERRELL, TX 30 24 34 23 37 / 20 10 10 10 20 CORSICANA, TX 31 25 34 25 35 / 60 10 10 10 20 TEMPLE, TX 31 26 33 25 35 / 60 20 20 10 20 && .FWD WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ135-146>148-158>162-174-175. && $$ 05/42/05 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1056 AM CST MON JAN 15 2007 .UPDATE... PROGRESSION OF WINTRY MIX OF PRECIPITATION...AND SUBSEQUENT DRYING/ SUBSIDENCE BEHIND THE BAND HAS BEEN MORE PROGRESSIVE THAN EARLIER EXPECTED AND MORE IN LINE WITH THE NAM/RUC MODELS...ESPECIALLY THEIR NEW 12Z RUNS...AS BEST MID LVL FRONTOGENESIS HAS SHIFTED OVER SE CWA. EXPECT DISTURBANCES IN SUBTROPICAL JET BRANCH TO CONTINUE TO GRAZE FAR SE COUNTIES THROUGH AT LEAST 00Z TUES. ALSO...DEEPER ARCTIC AIRMASS IS NOW ARRIVING PER LATEST VWP AND AREA SOUNDINGS (THOUGH 12Z FWD WAS A NO GO). DESPITE SUNSHINE OVER NW 1/2 OF N TX...DEEP/DENSE AIRMASS THROUGH 5 KFT WON`T ALLOW MUCH IN THE WAY OF WARMING...THOUGH INSOLATION AND TRAFFIC SHOULD HELP IN THE SUBLIMATION AFFECTS OF EARLIER ICE ACCUMULATIONS. AS A RESULT...ICE STORM WARNING HAS BEEN CANCELED OVER THE NW 1/2... WITH THE FREEZING RAIN ADVISORY CANCELED OVER NE COUNTIES. FREEZING RAIN ADVISORY CONTS OVER SE COUNTIES (SE OF A LAMPASAS...WACO... CORSICANA...CANTON LINE). SEE ADVISORY LINE BELOW. ADVISORY/WARNING INFORMATION ALREADY SENT VIA FTWWSWFWD. FORECASTS AND HAZARDOUS WX OUTLOOK UPDATED FOR CURRENT TRENDS AS WELL. WE WILL BE ISSUING AN SPS FOR CONTINUED ICY ROADS/HIGHWAYS SHORTLY... NAMELY FOR BRIDGES AND OVERPASSES AND SECONDARY ROADS. && .PREV DISCUSSION... /ISSUED 541 AM CST MON JAN 15 2007/ 12Z AVIATION UPDATE...BACK EDGE OF THE PRECIPITATION IS MOVING THROUGH THE METROPLEX NOW...BUT SEVERAL OB SITES STILL REPORTING SOME LIGHT FREEZING RAIN AND SLEET. SATELLITE IMAGERY SHOWS SOME CLEARING TO THE WEST...BUT STRONG SW FLOW ALOFT MAY KEEP SOME HIGH CLOUDINESS AROUND FOR A WHILE. WILL START OUT WITH IMPROVING CONDS AND ONLY KEEP A TEMPO GROUP IN UNTIL 14Z TO COVER LINGERING SLEET SHOWERS. CIGS IMPROVE TO VFR BY MID MORNING BUT GUSTY NORTHERLY WINDS WILL PERSIST THROUGH THE EARLY AFTERNOON. EXPECT VFR CIGS/VIS THROUGH THE END OF THE PERIOD. 91/DUNN PREV DISCUSSION... /ISSUED 409 AM CST MON JAN 15 2007/ MOST OF THE WINTER PRECIPITATION WILL SLOWLY COME TO AN END TODAY...AT LEAST IN THE ICE STORM WARNING AREA. HOWEVER...LIGHT PRECIP WILL CONTINUE INTO THE EVENING IN THE FAR SOUTH. WITH THE PRECIP SLOW TO END...WE WILL EXTEND THE ICE STORM WARNING UNTIL NOON TODAY AND CONTINUE THE FREEZING RAIN ADVISORY IN THE EAST. THE ADVISORY MAY HAVE TO BE ADJUSTED FOR TONIGHT BUT CONSIDERING THE SLOW MOVEMENT AND OTHER FACTORS...THIS WILL BE BETTER HANDLED BY THE DAY CREW. ADDITIONAL ICE ACCUMULATIONS WILL BE LESS THAN ONE QUARTER OF AN INCH IN THE WARNING AREA. MOST OF THE AREA IS WELL BELOW FREEZING THIS MORNING AND WITH OVERNIGHT RAIN...ICE HAS BECOME MORE OF A PROBLEM...ESPECIALLY ON ELEVATED SURFACES. THE MORNING COMMUTE WILL BE EXTREMELY DIFFICULT FOR MANY. WITH CONDITIONS IMPROVING LATER THIS MORNING AS THE PRECIP MOVES OUT...HOPEFULLY MANY WILL BE ABLE TO DELAY THEIR TRAVELS A FEW HOURS. STILL...WHERE THE TEMPERATURE HAS BEEN BELOW FREEZING FOR THE LAST DAY OR SO...ICE HAS BEGUN TO ACCUMULATE ON SURFACES SUCH AS SIDEWALKS...MAKING EVEN WALKING DIFFICULT AT TIMES. THIS SHOULD ALSO IMPROVE AFTER THE PRECIP ENDS WITH GUSTY NORTH WINDS DRYING SURFACES. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THIS WEEK...IN FACT RATHER COLD THE NEXT FEW DAYS AS NORTH WINDS AND CLOUDINESS PERSIST. LIGHT PRECIP WILL PERSIST TONIGHT IN THE SOUTH BUT DO NOT ANTICIPATE SIGNIFICANT ACCUMULATIONS...AND TUESDAY WILL BE DRY. HOWEVER...ON WEDNESDAY WE WILL SEE ANOTHER UPPER LEVEL DISTURBANCE MOVE ACROSS THE AREA. WITH MORNING SURFACE LOWS WELL BELOW FREEZING...ALONG WITH THE COLUMN OF AIR ABOVE...WE COULD SEE SOME LIGHT SNOW IN THE MORNING...CHANGING MORE TO RAIN BY AFTERNOON. TEMPERATURES SHOULD SLOWLY WARM TO MORE NORMAL READINGS AFTER WEDNESDAY...WITH A CHANCE FOR RAIN BY THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 29 24 35 23 35 / 10 0 10 10 20 WACO, TX 30 25 34 25 35 / 40 10 10 10 20 PARIS, TX 29 21 34 20 36 / 10 0 10 10 20 DENTON, TX 29 20 35 22 35 / 10 0 10 10 20 MCKINNEY, TX 29 22 34 22 36 / 10 0 10 10 20 DALLAS, TX 29 25 35 23 38 / 10 0 10 10 20 TERRELL, TX 30 24 34 23 37 / 20 10 10 10 20 CORSICANA, TX 31 25 34 25 35 / 60 10 10 10 20 TEMPLE, TX 31 26 33 25 35 / 60 20 20 10 20 && .FWD WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ135-146>148-158>162-174-175. && $$ 05/42 tx AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE FORT WORTH TX 1205 PM CST SUN JAN 14 2007 .AVIATION... 1205 PM CST BULK OF RA/FZRA HAS EVACUATED METRO TAFS. SOME LINGERING FZDZ THIS AFTERNOON. REINFORCING COLD AIR WILL IMPROVE VSBY...BUT ANOTHER ROUND OF WINTRY PRECIP THIS EVENING AS NEXT IMPULSE APPROACHES. SOME SLEET POSSIBLE AS DEPTH OF COLD AIR INCREASES. BRISK NORTH WINDS ON MONDAY...BUT RAPIDLY IMPROVING CIGS. FOR WACO...ONSET OF FREEZING TEMPS AND FZRA MAY BE DELAYED UNTIL MID-EVENING...BUT PRECIP IN CENTRAL TEXAS WILL LINGER WELL AFTER 06Z. 25 && .UPDATE... 1125 AM CST CURRENT FORECAST PACKAGE INCLUDING WATCHES/WARNINGS/ADVISORIES LOOK OK FOR NOW. THE FREEZING LINE HAS NOT MOVED MUCH IN THE LAST 8 HOURS. LARGEST ACCUMULATIONS OF FREEZING RAIN WILL BE NORTH OF AN EASTLAND...MINERAL WELLS...TO GAINESVILLE LINE WHERE PERIODS OF MODERATE TO HEAVY FREEZING RAIN WILL CONTINUE TO CAUSE TRAVEL PROBLEMS. ELEVATED...EXPOSED SURFACES FURTHER SOUTH AND EAST IN THE ICE STORM WARNING WILL REMAIN FROZEN BUT AS OF NOW MANY ROADS ARE STILL WET. TRAVEL IS STILL DISCOURAGED IN THE ICE STORM WARNING DUE TO THE LIKELIHOOD OF ICE ON BRIDGES...OVERPASSES...AND FLY OVERS. STILL APPEARS THAT THE FREEZING LINE WILL SLIDE THROUGH NEARLY ALL OF NORTH TEXAS TONIGHT. WE WILL MOST LIKELY CHANGE THE WINTER STORM WATCH IN THE SOUTHEAST TO A FREEZING RAIN ADVISORY TONIGHT AND MONDAY AS ICE ACCUMULATIONS SHOULD BE LESS THAN 1/4 INCH AND MOST ROADS SHOULD NOT ICE OVER. NO CHANGES TO THE FORECAST ARE NEEDED AT THIS TIME. 79 && .AVIATION... 550 AM CST DIFFICULT FORECAST...AND AMENDMENTS ARE LIKELY AS TRENDS BECOME MORE APPARENT. CIGS ARE LOWERING...LIKELY IN RESPONSE TO THE APPROACHING SHORTWAVE...WITH PRESSURE FALLS NOTED ACROSS THE STATE. VSBYS WILL ALSO FALL TO MVFR/IFR DURING THE MORNING HOURS WITH FZDZ ACCOMPANYING THE BR AT TIMES. INCREASING 850 MB FLOW SHOULD ENHANCE ISENTROPIC LIFT DURING THE NEXT FEW HOURS WITH AN INCREASE IN SHRA. RUC/NAM FORECASTS ARE DEPICTING A TRAJECTORY OFF THE MEXICAN MOUNTAINS WHICH BRINGS DRY AIR INTO THE AREA AND ALTERS QPF PLACEMENT. PREFER THE GFS/UKMET/ECMWF LOW LEVEL WIND FORECAST WHICH ALIGNS WITH THE CURRENT TRENDS...AND SUGGESTS BEST CHANCE OF FZRA OVER THE METROPLEX AFTER 9 AM AND LASTING THROUGH LATE AFTERNOON. SUSPECT THAT BATCH OF SHOWERS NEAR AUSTIN IS THE BEGINNINGS OF THE ACTIVITY THAT WILL AFFECT THE METROPLEX. FOR ACT SAME TRENDS WITH CIGS/VSBYS HAVE BEEN FORECAST...BUT HAVE KEPT PRECIP LIQUID THROUGH THIS EVENING...BUT CHANGED IT TO FZRA THEREAFTER. WITH COLD ADVECTION INCREASING AFTER 0Z...HAVE RAISED CIGS/VSBYS AS COLD LAYER DEEPENS OVER METROPLEX. SOME SLEET MAY BE POSSIBLE AS WELL. TR.92 && .PREV DISCUSSION... 431 AM CST NORTH TEXAS WEATHER REMAINS VERY INTERESTING TODAY AS WE WILL CONTINUE TO SEE FREEZING RAIN IN THE WEST...AND A CHANCE OF FLOODING IN THE EAST. THE FREEZE LINE WILL ALSO NOT MOVE SIGNIFICANTLY TODAY BUT A SURGE OF MUCH COLDER AIR TONIGHT WILL PUSH IT INTO SOUTHERN ZONES BY MORNING. IN TURN...PRECIP SHOULD END IN NORTHERN PORTIONS TONIGHT...WITH LIGHT WINTER PRECIP DEVELOPING IN THE SOUTH. CURRENT ONGOING CONVECTION IN THE SOUTHEAST WILL BE A PROBLEM AGAIN TODAY. AS FOR HEAVY RAINS...WHILE WE DO NOT ANTICIPATE THE HEAVY RAINFALL AMOUNTS AS YESTERDAY...IT WILL NOT TAKE MUCH TO CAUSE FLOODING PROBLEMS. HENCE...WE WILL NOT CHANGE THE CURRENT WATCHES...WARNING OR ADVISORY. NEXT WAVE OF ENERGY IS EJECTING NORTHEAST INTO THE REGION THIS MORNING WITH RAIN AREA INCREASING AND MOVING INTO THE WESTERN CWA. THIS WILL BE A SIGNIFICANT PROBLEM AS TEMPERATURES WILL NOT WARM MUCH TODAY...KEEPING WESTERN PORTIONS AT OR BELOW FREEZING AS ICE CONTINUES TO ACCUMULATE. ON RADAR THE RETURNS MAY NOT LOOK SIGNIFICANT BUT WITH THE TEMPERATURE AT OR BELOW FREEZING FOR SUCH A LONG TIME...EVEN SMALL AMOUNTS CAN CAUSE SIGNIFICANT PROBLEMS ON BRIDGES...OVERPASSES...TREES AND POWER LINES. TOTAL ICE AMOUNTS THROUGH TONIGHT IN THE ICE STORM WARNING AREA WILL RANGE BETWEEN ONE QUARTER AND THREE QUARTERS OF AN INCH. SOME MINOR AMOUNTS OF SLEET WILL BE POSSIBLE LATER TODAY AND TONIGHT. WINTER PRECIP WILL MOVE INTO THE SOUTHERN PORTIONS LATER TONIGHT AS TEMPERATURES FINALLY BEGIN TO FALL. AT THE SAME TIME...THE SYSTEM WILL BEGIN TO WEAKEN...LESSENING THE CHANCE FOR SIGNIFICANT WINTER PRECIP. HOWEVER...AS EVENTS DEVELOP TODAY AND ADDITIONAL MODEL DATA IS REVIEWED...THE WATCH WILL BE MODIFIED AS NEEDED. IN THE EXTENDED PORTION OF THE FORECAST TEMPERATURES REMAIN BELOW NORMAL...BUT SHOULD REMAIN ABOVE FREEZING...WITH PERIODS OF RAIN TOWARD THE END OF THE WEEK. 42 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 24 31 20 33 / 100 80 30 10 10 WACO, TX 34 29 32 23 32 / 100 80 70 20 10 PARIS, TX 36 26 32 17 31 / 100 80 50 10 10 DENTON, TX 31 23 31 19 33 / 100 80 30 10 10 MCKINNEY, TX 32 24 31 19 32 / 100 80 30 10 10 DALLAS, TX 33 25 31 19 32 / 100 80 50 10 10 TERRELL, TX 34 27 32 19 32 / 100 80 50 10 10 CORSICANA, TX 35 29 32 21 31 / 100 100 70 20 10 TEMPLE, TX 36 29 32 23 31 / 100 100 70 40 20 && .FWD WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ091>094-100>104-115>120-129>133-141>144-156-157. FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ095-105>107-121>123-134-135-145>148-158>162-174-175. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ107-122-123-135-146>148-158>162-174-175. FREEZING RAIN ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ095-105-106-121-134-145. && $$ 79/25 07/09/77/20 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1125 AM CST SUN JAN 14 2007 .UPDATE... CURRENT FORECAST PACKAGE INCLUDING WATCHES/WARNINGS/ADVISORIES LOOK OK FOR NOW. THE FREEZING LINE HAS NOT MOVED MUCH IN THE LAST 8 HOURS. LARGEST ACCUMULATIONS OF FREEZING RAIN WILL BE NORTH OF AN EASTLAND...MINERAL WELLS...TO GAINESVILLE LINE WHERE PERIODS OF MODERATE TO HEAVY FREEZING RAIN WILL CONTINUE TO CAUSE TRAVEL PROBLEMS. ELEVATED...EXPOSED SURFACES FURTHER SOUTH AND EAST IN THE ICE STORM WARNING WILL REMAIN FROZEN BUT AS OF NOW MANY ROADS ARE STILL WET. TRAVEL IS STILL DISCOURAGED IN THE ICE STORM WARNING DUE TO THE LIKELIHOOD OF ICE ON BRIDGES...OVERPASSES...AND FLY OVERS. STILL APPEARS THAT THE FREEZING LINE WILL SLIDE THROUGH NEARLY ALL OF NORTH TEXAS TONIGHT. WE WILL MOST LIKELY CHANGE THE WINTER STORM WATCH IN THE SOUTHEAST TO A FREEZING RAIN ADVISORY TONIGHT AND MONDAY AS ICE ACCUMULATIONS SHOULD BE LESS THAN 1/4 INCH AND MOST ROADS SHOULD NOT ICE OVER. NO CHANGES TO THE FORECAST ARE NEEDED AT THIS TIME. 79. && .AVIATION... 550 AM DIFFICULT FORECAST...AND AMENDMENTS ARE LIKELY AS TRENDS BECOME MORE APPARENT. CIGS ARE LOWERING...LIKELY IN RESPONSE TO THE APPROACHING SHORTWAVE...WITH PRESSURE FALLS NOTED ACROSS THE STATE. VSBYS WILL ALSO FALL TO MVFR/IFR DURING THE MORNING HOURS WITH FZDZ ACCOMPANYING THE BR AT TIMES. INCREASING 850 MB FLOW SHOULD ENHANCE ISENTROPIC LIFT DURING THE NEXT FEW HOURS WITH AN INCREASE IN SHRA. RUC/NAM FORECASTS ARE DEPICTING A TRAJECTORY OFF THE MEXICAN MOUNTAINS WHICH BRINGS DRY AIR INTO THE AREA AND ALTERS QPF PLACEMENT. PREFER THE GFS/UKMET/ECMWF LOW LEVEL WIND FORECAST WHICH ALIGNS WITH THE CURRENT TRENDS...AND SUGGESTS BEST CHANCE OF FZRA OVER THE METROPLEX AFTER 9 AM AND LASTING THROUGH LATE AFTERNOON. SUSPECT THAT BATCH OF SHOWERS NEAR AUSTIN IS THE BEGINNINGS OF THE ACTIVITY THAT WILL AFFECT THE METROPLEX. FOR ACT SAME TRENDS WITH CIGS/VSBYS HAVE BEEN FORECAST...BUT HAVE KEPT PRECIP LIQUID THROUGH THIS EVENING...BUT CHANGED IT TO FZRA THEREAFTER. WITH COLD ADVECTION INCREASING AFTER 0Z...HAVE RAISED CIGS/VSBYS AS COLD LAYER DEEPENS OVER METROPLEX. SOME SLEET MAY BE POSSIBLE AS WELL. TR.92 && .DISCUSSION... NORTH TEXAS WEATHER REMAINS VERY INTERESTING TODAY AS WE WILL CONTINUE TO SEE FREEZING RAIN IN THE WEST...AND A CHANCE OF FLOODING IN THE EAST. THE FREEZE LINE WILL ALSO NOT MOVE SIGNIFICANTLY TODAY BUT A SURGE OF MUCH COLDER AIR TONIGHT WILL PUSH IT INTO SOUTHERN ZONES BY MORNING. IN TURN...PRECIP SHOULD END IN NORTHERN PORTIONS TONIGHT...WITH LIGHT WINTER PRECIP DEVELOPING IN THE SOUTH. CURRENT ONGOING CONVECTION IN THE SOUTHEAST WILL BE A PROBLEM AGAIN TODAY. AS FOR HEAVY RAINS...WHILE WE DO NOT ANTICIPATE THE HEAVY RAINFALL AMOUNTS AS YESTERDAY...IT WILL NOT TAKE MUCH TO CAUSE FLOODING PROBLEMS. HENCE...WE WILL NOT CHANGE THE CURRENT WATCHES...WARNING OR ADVISORY. NEXT WAVE OF ENERGY IS EJECTING NORTHEAST INTO THE REGION THIS MORNING WITH RAIN AREA INCREASING AND MOVING INTO THE WESTERN CWA. THIS WILL BE A SIGNIFICANT PROBLEM AS TEMPERATURES WILL NOT WARM MUCH TODAY...KEEPING WESTERN PORTIONS AT OR BELOW FREEZING AS ICE CONTINUES TO ACCUMULATE. ON RADAR THE RETURNS MAY NOT LOOK SIGNIFICANT BUT WITH THE TEMPERATURE AT OR BELOW FREEZING FOR SUCH A LONG TIME...EVEN SMALL AMOUNTS CAN CAUSE SIGNIFICANT PROBLEMS ON BRIDGES...OVERPASSES...TREES AND POWER LINES. TOTAL ICE AMOUNTS THROUGH TONIGHT IN THE ICE STORM WARNING AREA WILL RANGE BETWEEN ONE QUARTER AND THREE QUARTERS OF AN INCH. SOME MINOR AMOUNTS OF SLEET WILL BE POSSIBLE LATER TODAY AND TONIGHT. WINTER PRECIP WILL MOVE INTO THE SOUTHERN PORTIONS LATER TONIGHT AS TEMPERATURES FINALLY BEGIN TO FALL. AT THE SAME TIME...THE SYSTEM WILL BEGIN TO WEAKEN...LESSENING THE CHANCE FOR SIGNIFICANT WINTER PRECIP. HOWEVER...AS EVENTS DEVELOP TODAY AND ADDITIONAL MODEL DATA IS REVIEWED...THE WATCH WILL BE MODIFIED AS NEEDED. IN THE EXTENDED PORTION OF THE FORECAST TEMPERATURES REMAIN BELOW NORMAL...BUT SHOULD REMAIN ABOVE FREEZING...WITH PERIODS OF RAIN TOWARD THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 24 31 20 33 / 100 80 30 10 10 WACO, TX 34 29 32 23 32 / 100 80 70 20 10 PARIS, TX 36 26 32 17 31 / 100 80 50 10 10 DENTON, TX 31 23 31 19 33 / 100 80 30 10 10 MCKINNEY, TX 32 24 31 19 32 / 100 80 30 10 10 DALLAS, TX 33 25 31 19 32 / 100 80 50 10 10 TERRELL, TX 34 27 32 19 32 / 100 80 50 10 10 CORSICANA, TX 35 29 32 21 31 / 100 100 70 20 10 TEMPLE, TX 36 29 32 23 31 / 100 100 70 40 20 && .FWD WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ091>094-100>104-115>120-129>133-141>144-156-157. FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ095-105>107-121>123-134-135-145>148-158>162-174-175. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ107-122-123-135-146>148-158>162-174-175. FREEZING RAIN ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ095-105-106-121-134-145. && $$ 92/42 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 840 AM CST SUN JAN 14 2007 .UPDATE... AFTER REVIEWING THE MORNING SOUNDING AND CURRENT RADAR TRENDS WE WILL SEND OUT A QUICK UPDATE TO INCLUDE SOME ISOLATED THUNDER WHERE THE CURRENT ICE STORM WARNING RESIDES. WILL ALSO ADD THE MENTION OF SLEET IN THE EXTREME NORTHWEST THIS MORNING AND A LITTLE FURTHER SOUTH THIS AFTERNOON. NO OTHER CHANGES WITH THIS UPDATE. .79 && .AVIATION... 550 AM DIFFICULT FORECAST...AND AMENDMENTS ARE LIKELY AS TRENDS BECOME MORE APPARENT. CIGS ARE LOWERING...LIKELY IN RESPONSE TO THE APPROACHING SHORTWAVE...WITH PRESSURE FALLS NOTED ACROSS THE STATE. VSBYS WILL ALSO FALL TO MVFR/IFR DURING THE MORNING HOURS WITH FZDZ ACCOMPANYING THE BR AT TIMES. INCREASING 850 MB FLOW SHOULD ENHANCE ISENTROPIC LIFT DURING THE NEXT FEW HOURS WITH AN INCREASE IN SHRA. RUC/NAM FORECASTS ARE DEPICTING A TRAJECTORY OFF THE MEXICAN MOUNTAINS WHICH BRINGS DRY AIR INTO THE AREA AND ALTERS QPF PLACEMENT. PREFER THE GFS/UKMET/ECMWF LOW LEVEL WIND FORECAST WHICH ALIGNS WITH THE CURRENT TRENDS...AND SUGGESTS BEST CHANCE OF FZRA OVER THE METROPLEX AFTER 9 AM AND LASTING THROUGH LATE AFTERNOON. SUSPECT THAT BATCH OF SHOWERS NEAR AUSTIN IS THE BEGINNINGS OF THE ACTIVITY THAT WILL AFFECT THE METROPLEX. FOR ACT SAME TRENDS WITH CIGS/VSBYS HAVE BEEN FORECAST...BUT HAVE KEPT PRECIP LIQUID THROUGH THIS EVENING...BUT CHANGED IT TO FZRA THEREAFTER. WITH COLD ADVECTION INCREASING AFTER 0Z...HAVE RAISED CIGS/VSBYS AS COLD LAYER DEEPENS OVER METROPLEX. SOME SLEET MAY BE POSSIBLE AS WELL. TR.92 && .DISCUSSION... NORTH TEXAS WEATHER REMAINS VERY INTERESTING TODAY AS WE WILL CONTINUE TO SEE FREEZING RAIN IN THE WEST...AND A CHANCE OF FLOODING IN THE EAST. THE FREEZE LINE WILL ALSO NOT MOVE SIGNIFICANTLY TODAY BUT A SURGE OF MUCH COLDER AIR TONIGHT WILL PUSH IT INTO SOUTHERN ZONES BY MORNING. IN TURN...PRECIP SHOULD END IN NORTHERN PORTIONS TONIGHT...WITH LIGHT WINTER PRECIP DEVELOPING IN THE SOUTH. CURRENT ONGOING CONVECTION IN THE SOUTHEAST WILL BE A PROBLEM AGAIN TODAY. AS FOR HEAVY RAINS...WHILE WE DO NOT ANTICIPATE THE HEAVY RAINFALL AMOUNTS AS YESTERDAY...IT WILL NOT TAKE MUCH TO CAUSE FLOODING PROBLEMS. HENCE...WE WILL NOT CHANGE THE CURRENT WATCHES...WARNING OR ADVISORY. NEXT WAVE OF ENERGY IS EJECTING NORTHEAST INTO THE REGION THIS MORNING WITH RAIN AREA INCREASING AND MOVING INTO THE WESTERN CWA. THIS WILL BE A SIGNIFICANT PROBLEM AS TEMPERATURES WILL NOT WARM MUCH TODAY...KEEPING WESTERN PORTIONS AT OR BELOW FREEZING AS ICE CONTINUES TO ACCUMULATE. ON RADAR THE RETURNS MAY NOT LOOK SIGNIFICANT BUT WITH THE TEMPERATURE AT OR BELOW FREEZING FOR SUCH A LONG TIME...EVEN SMALL AMOUNTS CAN CAUSE SIGNIFICANT PROBLEMS ON BRIDGES...OVERPASSES...TREES AND POWER LINES. TOTAL ICE AMOUNTS THROUGH TONIGHT IN THE ICE STORM WARNING AREA WILL RANGE BETWEEN ONE QUARTER AND THREE QUARTERS OF AN INCH. SOME MINOR AMOUNTS OF SLEET WILL BE POSSIBLE LATER TODAY AND TONIGHT. WINTER PRECIP WILL MOVE INTO THE SOUTHERN PORTIONS LATER TONIGHT AS TEMPERATURES FINALLY BEGIN TO FALL. AT THE SAME TIME...THE SYSTEM WILL BEGIN TO WEAKEN...LESSENING THE CHANCE FOR SIGNIFICANT WINTER PRECIP. HOWEVER...AS EVENTS DEVELOP TODAY AND ADDITIONAL MODEL DATA IS REVIEWED...THE WATCH WILL BE MODIFIED AS NEEDED. IN THE EXTENDED PORTION OF THE FORECAST TEMPERATURES REMAIN BELOW NORMAL...BUT SHOULD REMAIN ABOVE FREEZING...WITH PERIODS OF RAIN TOWARD THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 24 31 20 33 / 100 80 30 10 10 WACO, TX 34 29 32 23 32 / 100 80 70 20 10 PARIS, TX 36 26 32 17 31 / 100 80 50 10 10 DENTON, TX 31 23 31 19 33 / 100 80 30 10 10 MCKINNEY, TX 32 24 31 19 32 / 100 80 30 10 10 DALLAS, TX 33 25 31 19 32 / 100 80 50 10 10 TERRELL, TX 34 27 32 19 32 / 100 80 50 10 10 CORSICANA, TX 35 29 32 21 31 / 100 100 70 20 10 TEMPLE, TX 36 29 32 23 31 / 100 100 70 40 20 && .FWD WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ091>094-100>104-115>120-129>133-141>144-156-157. FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ095-105>107-121>123-134-135-145>148-158>162-174-175. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ107-122-123-135-146>148-158>162-174-175. FREEZING RAIN ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ095-105-106-121-134-145. && $$ 92/42 tx AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE FORT WORTH TX 550 AM CST SUN JAN 14 2007 .AVIATION... DIFFICULT FORECAST...AND AMENDMENTS ARE LIKELY AS TRENDS BECOME MORE APPARENT. CIGS ARE LOWERING...LIKELY IN RESPONSE TO THE APPROACHING SHORTWAVE...WITH PRESSURE FALLS NOTED ACROSS THE STATE. VSBYS WILL ALSO FALL TO MVFR/IFR DURING THE MORNING HOURS WITH FZDZ ACCOMPANYING THE BR AT TIMES. INCREASING 850 MB FLOW SHOULD ENHANCE ISENTROPIC LIFT DURING THE NEXT FEW HOURS WITH AN INCREASE IN SHRA. RUC/NAM FORECASTS ARE DEPICTING A TRAJECTORY OFF THE MEXICAN MOUNTAINS WHICH BRINGS DRY AIR INTO THE AREA AND ALTERS QPF PLACEMENT. PREFER THE GFS/UKMET/ECMWF LOW LEVEL WIND FORECAST WHICH ALIGNS WITH THE CURRENT TRENDS...AND SUGGESTS BEST CHANCE OF FZRA OVER THE METROPLEX AFTER 9 AM AND LASTING THROUGH LATE AFTERNOON. SUSPECT THAT BATCH OF SHOWERS NEAR AUSTIN IS THE BEGINNINGS OF THE ACTIVITY THAT WILL AFFECT THE METROPLEX. FOR ACT SAME TRENDS WITH CIGS/VSBYS HAVE BEEN FORECAST...BUT HAVE KEPT PRECIP LIQUID THROUGH THIS EVENING...BUT CHANGED IT TO FZRA THEREAFTER. WITH COLD ADVECTION INCREASING AFTER 0Z...HAVE RAISED CIGS/VSBYS AS COLD LAYER DEEPENS OVER METROPLEX. SOME SLEET MAY BE POSSIBLE AS WELL. TR.92 && .DISCUSSION... NORTH TEXAS WEATHER REMAINS VERY INTERESTING TODAY AS WE WILL CONTINUE TO SEE FREEZING RAIN IN THE WEST...AND A CHANCE OF FLOODING IN THE EAST. THE FREEZE LINE WILL ALSO NOT MOVE SIGNIFICANTLY TODAY BUT A SURGE OF MUCH COLDER AIR TONIGHT WILL PUSH IT INTO SOUTHERN ZONES BY MORNING. IN TURN...PRECIP SHOULD END IN NORTHERN PORTIONS TONIGHT...WITH LIGHT WINTER PRECIP DEVELOPING IN THE SOUTH. CURRENT ONGOING CONVECTION IN THE SOUTHEAST WILL BE A PROBLEM AGAIN TODAY. AS FOR HEAVY RAINS...WHILE WE DO NOT ANTICIPATE THE HEAVY RAINFALL AMOUNTS AS YESTERDAY...IT WILL NOT TAKE MUCH TO CAUSE FLOODING PROBLEMS. HENCE...WE WILL NOT CHANGE THE CURRENT WATCHES...WARNING OR ADVISORY. NEXT WAVE OF ENERGY IS EJECTING NORTHEAST INTO THE REGION THIS MORNING WITH RAIN AREA INCREASING AND MOVING INTO THE WESTERN CWA. THIS WILL BE A SIGNIFICANT PROBLEM AS TEMPERATURES WILL NOT WARM MUCH TODAY...KEEPING WESTERN PORTIONS AT OR BELOW FREEZING AS ICE CONTINUES TO ACCUMULATE. ON RADAR THE RETURNS MAY NOT LOOK SIGNIFICANT BUT WITH THE TEMPERATURE AT OR BELOW FREEZING FOR SUCH A LONG TIME...EVEN SMALL AMOUNTS CAN CAUSE SIGNIFICANT PROBLEMS ON BRIDGES...OVERPASSES...TREES AND POWER LINES. TOTAL ICE AMOUNTS THROUGH TONIGHT IN THE ICE STORM WARNING AREA WILL RANGE BETWEEN ONE QUARTER AND THREE QUARTERS OF AN INCH. SOME MINOR AMOUNTS OF SLEET WILL BE POSSIBLE LATER TODAY AND TONIGHT. WINTER PRECIP WILL MOVE INTO THE SOUTHERN PORTIONS LATER TONIGHT AS TEMPERATURES FINALLY BEGIN TO FALL. AT THE SAME TIME...THE SYSTEM WILL BEGIN TO WEAKEN...LESSENING THE CHANCE FOR SIGNIFICANT WINTER PRECIP. HOWEVER...AS EVENTS DEVELOP TODAY AND ADDITIONAL MODEL DATA IS REVIEWED...THE WATCH WILL BE MODIFIED AS NEEDED. IN THE EXTENDED PORTION OF THE FORECAST TEMPERATURES REMAIN BELOW NORMAL...BUT SHOULD REMAIN ABOVE FREEZING...WITH PERIODS OF RAIN TOWARD THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 24 31 20 33 / 100 80 30 10 10 WACO, TX 34 29 32 23 32 / 100 80 70 20 10 PARIS, TX 36 26 32 17 31 / 100 80 50 10 10 DENTON, TX 31 23 31 19 33 / 100 80 30 10 10 MCKINNEY, TX 32 24 31 19 32 / 100 80 30 10 10 DALLAS, TX 33 25 31 19 32 / 100 80 50 10 10 TERRELL, TX 34 27 32 19 32 / 100 80 50 10 10 CORSICANA, TX 35 29 32 21 31 / 100 100 70 20 10 TEMPLE, TX 36 29 32 23 31 / 100 100 70 40 20 && .FWD WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ091>094-100>104-115>120-129>133-141>144-156-157. FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ095-105>107-121>123-134-135-145>148-158>162-174-175. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ107-122-123-135-146>148-158>162-174-175. FREEZING RAIN ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: TXZ095-105-106-121-134-145. && $$ 92/42 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 100 PM EST MON JAN 15 2007 .AVIATION /18Z-18Z/... MVFR CEILINGS AT DAN WILL CONTINUE TO LIFT THIS AFTERNOON WITH CONDITIONS BECOMING VFR BY 21Z. SHOWERS WILL GRADUALLY MOVE WEST INTO THE MOUNTAINS THIS EVENING. CEILINGS ARE EXPECTED TO REMAIN VFR WITH MVFR VISIBILITIES IN THE RAIN. FOLLOWING THE PASSAGE OF THE COLD FRONT BETWEEN 06-12Z TUESDAY...CEILINGS WILL DROP TO MVFR IN THE MOUNTAINS. WINDS WILL ALSO BE GUSTY OUT OF THE NORTHWEST BEHIND THE FRONT. && .PREV DISCUSSION... /ISSUED 1032 AM EST MON JAN 15 2007/ SHORT TERM /REST OF TODAY/... LATEST RUC AND 06Z NAM HAD THE BEST HANDLE ON THE TIMING AND LOCATION OF THE FRONT THIS MORNING. HAVE SLOWED DOWN THE ARRIVAL OF THE RAIN BY A COUPLE OF HOURS. WINDS IN THE PIEDMONT ARE ALREADY GUSTING UP TO 20 KNOTS. GSO 12Z SOUNDING HAD 35 KNOT WINDS BELOW 2000 FEET SO HAVE RAISED WIND SPEEDS...ESPECIALLY AT HIGHER ELEVATIONS. ALSO MADE SLIGHT TWEAKS TO HIGH TEMPERATURES TODAY BASED ON THE LATEST LAMP GUIDANCE AND CURRENT TEMPERATURES. NO OTHER CHANGES AT THIS TIME. PREV DISCUSSION... /ISSUED 621 AM EST MON JAN 15 2007/ AVIATION /12Z-12Z/... MOISTURE WILL INCREASE ACROSS THE REGION TODAY WITH OCNL MVFR IN LOW CLOUDS ACROSS THE SOUTH THIS MORNING AND AT BLF/LWB THIS AFTERNOON. EXPECT ANY REDUCTIONS IN VSBY DUE TO -SHRA TO HOLD OFF ACROSS SE WVA UNTIL EARLY THIS AFTERNOON AND ELSEWHERE BY EARLY EVENING. STRONG SW JET ALOFT WILL MAKE FOR EARLY WIND SHEAR PROBLEMS ESPCLY WHERE SURFACE REMAIN LIGHT SO WILL INCLUDE IN A FEW SPOTS UNTIL BETTER MIXING DEVELOPS. COLD FRONT MOVES THROUGH FROM THE WEST OVERNIGHT PRECEDED BY A BAND OF SHRA. THIS SHOULD KEEP PREVAILING MVFR CONDITIONS AT LWB/BLF BUT MAINLY VFR IN THE EAST WHERE PRECIP SHOULD BE RATHER LIGHT. MAY HAVE A PERIOD OF IFR ESPCLY BLF BY 12Z TUE WHEN RAIN WILL HAVE LIKELY CHANGED TO -SHSN...OTRW RANGE FROM CONTINUED MVFR SE WVA TO VFR CEILINGS ELSEWHERE INTO EARLY TUE. PREV DISCUSSION... /ISSUED 251 AM EST MON JAN 15 2007/ SHORT TERM /TODAY THROUGH TUESDAY/... COLD FRONT EXTENDING FROM THE OHIO VALLEY SW TO THE ARKLATEX WILL FINALLY START TO SHIFT EAST TODAY AS FINAL SURFACE LOW AND UPPER SYSTEM SHEAR BY TO THE NW. HOWEVER STRONG UPPER RIDGE OVER THE SE SHOULD BE ABLE TO AGAIN SLOW THE FRONT AND ASSOCIATED DEEP MOISTURE ENOUGH TO ALLOW ANOTHER VERY MILD DAY ACROSS THE AREA. THIS SUPPORTED BY MODEL RH SECTIONS WHICH INDICATE MID/HIGH CLOUDS EARLY THEN INCREASING LOW LEVEL MOISTURE BEFORE ARC OF SHRA WORKS INTO THE FAR WESTERN ZONES BY MID OR LATE AFTERNOON. ALSO GIVEN PARALLEL NATURE OF BOUNDARY TO UPPER FLOW AND RAIN BEING WELL WEST EARLY THIS MORNING...PLAN TO SLOW POPS...WITH ANY CHANCES FAR WESTERN SLOPES TOWARD EARLY AFTERNOON...THEN QUICKLY INCREASING TO LIKELY/CAT LATE AS EDGE OF PRECIP SHIELD ARRIVES. MAY BE TOUGH TO SEE MUCH PRECIP AT ALL EAST OF THE BLUE RIDGE UNTIL THIS EVENING...SO CUTTING BACK TO 20/30 POP AND BASICALLY DRY SOUTHSIDE VA. ALTHO NOT QUITE AS WARM ALOFT TODAY...WARM START AND INCREASING SW TRAJECTORY SHOULD AGAIN SEND HIGHS ABOVE 70 EAST...AND INTO THE 60S WEST PENDING AMOUNT OF SUNSHINE. FRONT SHOULD CROSS THE MOUNTAINS THIS EVENING AND EXIT THE COAST TUE MORNING. PRE-FRONTAL MOISTURE GETS QUITE STRETCHED OUT CROSSING THE RIDGES WITH BEST SUPPORT EXITING NORTH WHILE INSTABILITY WELL TO THE SOUTH. EXPECT BEST COVERAGE FAR WEST EARLY ON AS BAND OF SHRA NUDGES EAST AND WEAKENS BEFORE JUMPING INTO THE PIEDMONT TOWARD MORNING AS NEXT WEAK IMPULSE RIDES UP THE FRONT. THEREFORE LIKELY POPS WEST AND FAR SE...WITH MAINLY CHANCE BLUE RIDGE WHERE RH LOOKS LIMITED BY LEFTOVER MID LEVEL DRY AIR PER RAOBS. 85H FRONT SHOULD CHASE DOWN ANY LINGERING SHRA FAR NW TOWARD MORNING WITH CHANGE TO -SHSN LIKELY BY 12Z. END OF WARMTH WILL BE MARKED BY STRONG COLD ADVECTION AIDED BY GUSTY NW WINDS AND TEMPS GOING NOWHERE ON TUE. MAY HAVE A FEW LINGERING SHRA PIEDMONT TUE MORNING...OTRW LOOKING AT A PERIOD OF UPSLOPE -SHSN ESPCLY NW SLOPES WHERE AN INCH OR TWO OF SNOW POSSIBLE. ELSEWHERE WILL CUT BACK POPS GIVEN DOWNSLOPE DRYING AND LOWERING DEWPTS. COULD BE A PERIOD OF WIND ADVISORY CRITERIA BLUE RIDGE AS COLD AIR SURGES IN EARLY TUE...OTRW BLUSTERY/COLD WITH HIGHS 30S WEST AND STEADY IN THE 40S OUT EAST. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... QUIET BUT COLD WEATHER IN STORE EARLY IN THE PERIOD AS LARGE SURFACE HIGH BUILDS EAST AND THEN SHIFTS OFFSHORE THU. FORTUNATELY CORE OF ARCTIC AIR WILL SLIDE BY TO THE NORTH...WITH COLDER 85H TEMPS LIFTING OUT THRU THURSDAY ALLOWING A SLOW TEMP MODERATION UNDER SUNSHINE. NEXT 5H TROF WILL SWING SE TOWARD THE MID ATLANTIC BY FRIDAY AS QUICK SHOT OF SOUTHERN STREAM RH ATTEMPTS TO LINK UP ALONG THE COAST LATE THU NIGHT/EARLY FRIDAY. GFS FARTHEST WEST OF ANY MODELS WITH SECONDARY WEAK SURFACE LOW WHILE THE REST WELL SOUTH/EAST WITH RH LINKAGE. SINCE APPEARS FLOW TOO FAST FOR MUCH PHASING...WILL CONTINUE WITH ISOLATED POPS WITH THE NEXT FRONT FOR NOW. OTRW LOOKS LIKE YET ANOTHER COLD SHOT FOR NEXT WEEKEND BUT DRY OUTSIDE UPSLOPE -SHSN UNDER NORTHERN STREAM TROF. WILL LOWER HIGHS A BIT SAT/SUNDAY AS AIRMASS LOOKS COLDER OTRW FEW CHANGES. CLIMATE... RECORD HIGHS FOR JAN 15TH BLACKSBURG...61 IN 1971 ROANOKE......73 IN 1952 LYHCHBURG....75 IN 1932 DANVILLE.....74 IN 1952 BLUEFIELD....60 IN 1995 PREV DISCUSSION... /ISSUED 1245 AM EST MON JAN 15 2007/ AVIATION... GENERALLY VFR CONDITIONS EXPECTED ACROSS THE REGION THROUGH AT LEAST THE EARLY AFTERNOON HOURS. COLD FRONT POISED TO SLOWLY MOVE INTO THE AREA BY THE LATE AFTERNOON. THIS FEATURE WILL BRING MVFR CONDITIONS AND SCATTERED SHOWERS TO SE WV AND THEN THESE WILL PROGRESS THROUGH THE AREA IN ASSOCIATION TO THE FRONT. BY MONDAY EVENING THE FRONT SHOULD BE THROUGH THE REGION WITH WINDS WESTERLY ACROSS THE AREA WITH CEILINGS RETURNING TO VFR LEVELS. STRONG LOW LEVEL JET IN ADVANCE OF THE COLD FRONT SHOULD HELP MAINTAIN LOW LEVEL WIND SHEAR ABOVE THE WV TAF SITES THROUGH SUNRISE TODAY. PREV DISCUSSION... /ISSUED 920 PM EST SUN JAN 14 2007/ UPDATE... MADE SOME ADJUSTMENTS TO TEMPS OVERNIGHT...MOSTLY UP A DEG OR TWO. ITS GOING TO BE ANOTHER MILD NIGHT WITH PERIODS OF CLOUDINESS AND LOW LEVEL MIXING INCREASING LATE AS SFC PRESSURE GRADIENT TIGHTENS. OTHERWISE NO CHGS. PREV DISCUSSION... /ISSUED 618 PM EST SUN JAN 14 2007/ AVIATION /23Z-18Z/... LARGE SURFACE RIDGE OF HIGH PRESSURE CENTERED OFF THE MID ATLANTIC AND SOUTHEASTERN COAST WILL GRADUALLY RETREAT EAST THROUGH THE PERIOD AS LOW PRESSURE DEVELOPS OVER NORTHEASTERN TEXAS AND LIFTS NORTHEAST INTO THE OHIO VALLEY BY SUNRISE. INCREASING PRESSURE GRADIENT BETWEEN THE TWO SYSTEMS...AND SCATTERED TO BROKEN CANOPY OF MID AND HIGH LEVEL CLOUDS...SHOULD MINIMIZE POTENTIAL FOR SIGNIFICANT RADIATIONAL COOLING AND KEEP THE LOWER ATMOSPHERE ADEQUATELY MIXED TO PREVENT DEVELOPMENT OF ANY WIDESPREAD FOG OR LOW CEILING CONDITIONS. DESPITE THE ABOVE...THE REDEVELOPMENT OF SOME LOCALIZED FOG IN THE MOST SHELTERED OF LOW LYING AREAS SUCH AS LEWISBURG WILL LIKELY OCCUR AGAIN TONIGHT UNTIL SHORTLY AFTER DAYBREAK. OTHERWISE...THE APPROACH OF A STRONG COLD FRONT FROM THE NORTHWEST WILL RESULT IN AN INCREASE OF CLOUDS AND THREAT OF PRECIPITATION AS MONDAY PROGRESSES. THE BEST THREAT OF PRECIPITATION WILL ARRIVE AFTER 18Z. VFR CONDITIONS WILL DETERIORATE TO MVFR...POSSIBLY IFR ALONG WESTERN SLOPES DURING THE AFTERNOON. ALSO BEFORE THE FRONTAL PRECIP ARRIVES...INCREASING SOUTHWESTERLY JET WILL MIX TO THE SURFACE FROM MID MONDAY MORNING AND INTO THE AFTERNOON. SUSTAINED WINDS WILL BE ON THE ORDER OF 12-18KTS WITH GUSTS UP TO 25-30KTS. HIGHER WINDS SPEEDS ARE POSSIBLE ABOVE 5KFT WITH A 50+KT LOW LEVEL JET TRANSVERSING THE REGION. PREV DISCUSSION... /ISSUED 153 PM EST SUN JAN 14 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... STRONG SHORT WAVE IN THE CENTRAL ROCKIES LIFTS INTO THE GREAT LAKES ON MONDAY AND PUSHES THE UPPER TROF THROUGH THE FORECAST AREA ON TUESDAY NIGHT. IN AN EFFORT TO NARROW DOWN WHEN BEST CHANCE OF RAIN WILL BE WILL REMOVE ANY CHANCE BEFORE NOON ON MONDAY. MODELS HAVE A SHORT WAVE COMING THROUGH ON MONDAY EVENING WITH Q-V FORCING AND SOME FRONTOGENESIS. THERE ARE WEST TO SOUTHWEST LOW LEVEL WINDS AND NO ISENTROPIC LIFT ALONG AND AHEAD OF THE FRONT HOWEVER...SO PRECIPITATION AMOUNTS WILL BE LOW. GUIDANCE IS STILL SHOWING A SPLIT IN RAINFALL AMOUNTS TO THE NORTHWEST AND SOUTH OF THE COUNTY WARNING AREA. BASING THE TIMING OF THE FRONT ON THE GFS. THE SURFACE FRONT COMES THROUGH THE COUNTY WARNING AREA ON MONDAY EVENING...WITH THE 850 MB FRONTAL PASSAGE ON TUESDAY MORNING. DEEP MOISTURE CROSSES THE FORECAST AREA BETWEEN 18Z MONDAY AND 06Z TUESDAY. THEN CLOUDS WILL CLEAR IN THE SOUTHEAST ON TUESDAY AND IN THE NORTHWEST ON WEDNESDAY MORNING. VERY DRY AIRMASS WILL THEN RESULT IN LITTLE TO NO CLOUD COVER THROUGH THURSDAY MORNING. HIGH PRESSURE NOW OVER THE NORTHERN ROCKIES WITH TEMPERATURES IN THE SINGLE DIGITS AND TEENS...AND SURFACE DEWPOINTS AROUND ZERO BUILDS IN BEHIND THE FRONT...CROSSES THE FORECAST AREA ON WEDNESDAY THEN MOVES OFFSHORE BY THURSDAY MORNING. THE ARCTIC AIRMASS WILL MODIFY BY THE TIME IT REACHES THE MID ATLANTIC STATES...BUT AREA IS STILL LOOKING AT TEMPERATURES BY TUESDAY AROUND 25 DEGREES COLDER THAN THE RECORD SETTING WARMTH TODAY. WILL HAVE STEADY OR FALLING TEMPERATURE TRENDS ON TUESDAY ALONG WITH GUSTY WINDS. SURFACE WINDS WILL START TO DIMINISH ON TUESDAY NIGHT AS THE HIGH APPROACHES. USED CURRENT TRENDS OF THE MAV GUIDANCE FOR LOWS TONIGHT AND HIGHS ON MONDAY. BIGGEST DEPARTURE FROM MAV NUMBERS WAS TO RAISE MAXIMUM TEMPERATURES FOR LEWISBURG. LONG TERM /THURSDAY THROUGH SUNDAY/... LARGE RANGE OF SOLUTIONS BETWEEN DIFFERENT MODELS BY THE END OF THE WEEK. OPERATIONAL GFS HAS MORE PROGRESSIVE SOUTHWEST UNITED STATES LOW AND STRONGER UPPER RIDGE IN THE SOUTHEAST WHILE ECMWF HAS A DEEPER TROF IN THE NORTHEAST. GFS ENSEMBLES ARE A COMPROMISE BETWEEN THESE SOLUTIONS WITH TROFING IN THE WEST AND ZONAL FLOW IN THE EAST THURSDAY AND FRIDAY WITH A LONG WAVE TROF DIGGING IN THE NORTHEAST UNTIED STATES BY SATURDAY. THIS WILL INFLUENCE HOW FAST ANY MOISTURE WILL RETURN IN THE WEST SIDE OF THE ARCTIC HIGH. ALSO INDICATES ANY ORGANIZED SYNOPTIC LIFT WILL BE IN THE REGION ON SATURDAY AND SUNDAY AS THE TROF DEEPENS IN THE NORTHEAST. WILL INTRODUCE LOW CHANCE OF PRECIPITATION ON FRIDAY AND SATURDAY. ALSO HAVE TEMPERATURES SLIGHTLY COOLER THAN MEX GUIDANCE FOR FRIDAY THROUGH SUNDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AVIATION...AMS va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1032 AM EST MON JAN 15 2007 .SHORT TERM /REST OF TODAY/... LATEST RUC AND 06Z NAM HAD THE BEST HANDLE ON THE TIMING AND LOCATION OF THE FRONT THIS MORNING. HAVE SLOWED DOWN THE ARRIVAL OF THE RAIN BY A COUPLE OF HOURS. WINDS IN THE PIEDMONT ARE ALREADY GUSTING UP TO 20 KNOTS. GSO 12Z SOUNDING HAD 35 KNOT WINDS BELOW 2000 FEET SO HAVE RAISED WIND SPEEDS...ESPECIALLY AT HIGHER ELEVATIONS. ALSO MADE SLIGHT TWEAKS TO HIGH TEMPERATURES TODAY BASED ON THE LATEST LAMP GUIDANCE AND CURRENT TEMPERATURES. NO OTHER CHANGES AT THIS TIME. && .PREV DISCUSSION... /ISSUED 621 AM EST MON JAN 15 2007/ AVIATION /12Z-12Z/... MOISTURE WILL INCREASE ACROSS THE REGION TODAY WITH OCNL MVFR IN LOW CLOUDS ACROSS THE SOUTH THIS MORNING AND AT BLF/LWB THIS AFTERNOON. EXPECT ANY REDUCTIONS IN VSBY DUE TO -SHRA TO HOLD OFF ACROSS SE WVA UNTIL EARLY THIS AFTERNOON AND ELSEWHERE BY EARLY EVENING. STRONG SW JET ALOFT WILL MAKE FOR EARLY WIND SHEAR PROBLEMS ESPCLY WHERE SURFACE REMAIN LIGHT SO WILL INCLUDE IN A FEW SPOTS UNTIL BETTER MIXING DEVELOPS. COLD FRONT MOVES THROUGH FROM THE WEST OVERNIGHT PRECEDED BY A BAND OF SHRA. THIS SHOULD KEEP PREVAILING MVFR CONDITIONS AT LWB/BLF BUT MAINLY VFR IN THE EAST WHERE PRECIP SHOULD BE RATHER LIGHT. MAY HAVE A PERIOD OF IFR ESPCLY BLF BY 12Z TUE WHEN RAIN WILL HAVE LIKELY CHANGED TO -SHSN...OTRW RANGE FROM CONTINUED MVFR SE WVA TO VFR CEILINGS ELSEWHERE INTO EARLY TUE. PREV DISCUSSION... /ISSUED 251 AM EST MON JAN 15 2007/ SHORT TERM /TODAY THROUGH TUESDAY/... COLD FRONT EXTENDING FROM THE OHIO VALLEY SW TO THE ARKLATEX WILL FINALLY START TO SHIFT EAST TODAY AS FINAL SURFACE LOW AND UPPER SYSTEM SHEAR BY TO THE NW. HOWEVER STRONG UPPER RIDGE OVER THE SE SHOULD BE ABLE TO AGAIN SLOW THE FRONT AND ASSOCIATED DEEP MOISTURE ENOUGH TO ALLOW ANOTHER VERY MILD DAY ACROSS THE AREA. THIS SUPPORTED BY MODEL RH SECTIONS WHICH INDICATE MID/HIGH CLOUDS EARLY THEN INCREASING LOW LEVEL MOISTURE BEFORE ARC OF SHRA WORKS INTO THE FAR WESTERN ZONES BY MID OR LATE AFTERNOON. ALSO GIVEN PARALLEL NATURE OF BOUNDARY TO UPPER FLOW AND RAIN BEING WELL WEST EARLY THIS MORNING...PLAN TO SLOW POPS...WITH ANY CHANCES FAR WESTERN SLOPES TOWARD EARLY AFTERNOON...THEN QUICKLY INCREASING TO LIKELY/CAT LATE AS EDGE OF PRECIP SHIELD ARRIVES. MAY BE TOUGH TO SEE MUCH PRECIP AT ALL EAST OF THE BLUE RIDGE UNTIL THIS EVENING...SO CUTTING BACK TO 20/30 POP AND BASICALLY DRY SOUTHSIDE VA. ALTHO NOT QUITE AS WARM ALOFT TODAY...WARM START AND INCREASING SW TRAJECTORY SHOULD AGAIN SEND HIGHS ABOVE 70 EAST...AND INTO THE 60S WEST PENDING AMOUNT OF SUNSHINE. FRONT SHOULD CROSS THE MOUNTAINS THIS EVENING AND EXIT THE COAST TUE MORNING. PRE-FRONTAL MOISTURE GETS QUITE STRETCHED OUT CROSSING THE RIDGES WITH BEST SUPPORT EXITING NORTH WHILE INSTABILITY WELL TO THE SOUTH. EXPECT BEST COVERAGE FAR WEST EARLY ON AS BAND OF SHRA NUDGES EAST AND WEAKENS BEFORE JUMPING INTO THE PIEDMONT TOWARD MORNING AS NEXT WEAK IMPULSE RIDES UP THE FRONT. THEREFORE LIKELY POPS WEST AND FAR SE...WITH MAINLY CHANCE BLUE RIDGE WHERE RH LOOKS LIMITED BY LEFTOVER MID LEVEL DRY AIR PER RAOBS. 85H FRONT SHOULD CHASE DOWN ANY LINGERING SHRA FAR NW TOWARD MORNING WITH CHANGE TO -SHSN LIKELY BY 12Z. END OF WARMTH WILL BE MARKED BY STRONG COLD ADVECTION AIDED BY GUSTY NW WINDS AND TEMPS GOING NOWHERE ON TUE. MAY HAVE A FEW LINGERING SHRA PIEDMONT TUE MORNING...OTRW LOOKING AT A PERIOD OF UPSLOPE -SHSN ESPCLY NW SLOPES WHERE AN INCH OR TWO OF SNOW POSSIBLE. ELSEWHERE WILL CUT BACK POPS GIVEN DOWNSLOPE DRYING AND LOWERING DEWPTS. COULD BE A PERIOD OF WIND ADVISORY CRITERIA BLUE RIDGE AS COLD AIR SURGES IN EARLY TUE...OTRW BLUSTERY/COLD WITH HIGHS 30S WEST AND STEADY IN THE 40S OUT EAST. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... QUIET BUT COLD WEATHER IN STORE EARLY IN THE PERIOD AS LARGE SURFACE HIGH BUILDS EAST AND THEN SHIFTS OFFSHORE THU. FORTUNATELY CORE OF ARCTIC AIR WILL SLIDE BY TO THE NORTH...WITH COLDER 85H TEMPS LIFTING OUT THRU THURSDAY ALLOWING A SLOW TEMP MODERATION UNDER SUNSHINE. NEXT 5H TROF WILL SWING SE TOWARD THE MID ATLANTIC BY FRIDAY AS QUICK SHOT OF SOUTHERN STREAM RH ATTEMPTS TO LINK UP ALONG THE COAST LATE THU NIGHT/EARLY FRIDAY. GFS FARTHEST WEST OF ANY MODELS WITH SECONDARY WEAK SURFACE LOW WHILE THE REST WELL SOUTH/EAST WITH RH LINKAGE. SINCE APPEARS FLOW TOO FAST FOR MUCH PHASING...WILL CONTINUE WITH ISOLATED POPS WITH THE NEXT FRONT FOR NOW. OTRW LOOKS LIKE YET ANOTHER COLD SHOT FOR NEXT WEEKEND BUT DRY OUTSIDE UPSLOPE -SHSN UNDER NORTHERN STREAM TROF. WILL LOWER HIGHS A BIT SAT/SUNDAY AS AIRMASS LOOKS COLDER OTRW FEW CHANGES. CLIMATE... RECORD HIGHS FOR JAN 15TH BLACKSBURG...61 IN 1971 ROANOKE......73 IN 1952 LYHCHBURG....75 IN 1932 DANVILLE.....74 IN 1952 BLUEFIELD....60 IN 1995 PREV DISCUSSION... /ISSUED 1245 AM EST MON JAN 15 2007/ AVIATION... GENERALLY VFR CONDITIONS EXPECTED ACROSS THE REGION THROUGH AT LEAST THE EARLY AFTERNOON HOURS. COLD FRONT POISED TO SLOWLY MOVE INTO THE AREA BY THE LATE AFTERNOON. THIS FEATURE WILL BRING MVFR CONDITIONS AND SCATTERED SHOWERS TO SE WV AND THEN THESE WILL PROGRESS THROUGH THE AREA IN ASSOCIATION TO THE FRONT. BY MONDAY EVENING THE FRONT SHOULD BE THROUGH THE REGION WITH WINDS WESTERLY ACROSS THE AREA WITH CEILINGS RETURNING TO VFR LEVELS. STRONG LOW LEVEL JET IN ADVANCE OF THE COLD FRONT SHOULD HELP MAINTAIN LOW LEVEL WIND SHEAR ABOVE THE WV TAF SITES THROUGH SUNRISE TODAY. PREV DISCUSSION... /ISSUED 920 PM EST SUN JAN 14 2007/ UPDATE... MADE SOME ADJUSTMENTS TO TEMPS OVERNIGHT...MOSTLY UP A DEG OR TWO. ITS GOING TO BE ANOTHER MILD NIGHT WITH PERIODS OF CLOUDINESS AND LOW LEVEL MIXING INCREASING LATE AS SFC PRESSURE GRADIENT TIGHTENS. OTHERWISE NO CHGS. PREV DISCUSSION... /ISSUED 618 PM EST SUN JAN 14 2007/ AVIATION /23Z-18Z/... LARGE SURFACE RIDGE OF HIGH PRESSURE CENTERED OFF THE MID ATLANTIC AND SOUTHEASTERN COAST WILL GRADUALLY RETREAT EAST THROUGH THE PERIOD AS LOW PRESSURE DEVELOPS OVER NORTHEASTERN TEXAS AND LIFTS NORTHEAST INTO THE OHIO VALLEY BY SUNRISE. INCREASING PRESSURE GRADIENT BETWEEN THE TWO SYSTEMS...AND SCATTERED TO BROKEN CANOPY OF MID AND HIGH LEVEL CLOUDS...SHOULD MINIMIZE POTENTIAL FOR SIGNIFICANT RADIATIONAL COOLING AND KEEP THE LOWER ATMOSPHERE ADEQUATELY MIXED TO PREVENT DEVELOPMENT OF ANY WIDESPREAD FOG OR LOW CEILING CONDITIONS. DESPITE THE ABOVE...THE REDEVELOPMENT OF SOME LOCALIZED FOG IN THE MOST SHELTERED OF LOW LYING AREAS SUCH AS LEWISBURG WILL LIKELY OCCUR AGAIN TONIGHT UNTIL SHORTLY AFTER DAYBREAK. OTHERWISE...THE APPROACH OF A STRONG COLD FRONT FROM THE NORTHWEST WILL RESULT IN AN INCREASE OF CLOUDS AND THREAT OF PRECIPITATION AS MONDAY PROGRESSES. THE BEST THREAT OF PRECIPITATION WILL ARRIVE AFTER 18Z. VFR CONDITIONS WILL DETERIORATE TO MVFR...POSSIBLY IFR ALONG WESTERN SLOPES DURING THE AFTERNOON. ALSO BEFORE THE FRONTAL PRECIP ARRIVES...INCREASING SOUTHWESTERLY JET WILL MIX TO THE SURFACE FROM MID MONDAY MORNING AND INTO THE AFTERNOON. SUSTAINED WINDS WILL BE ON THE ORDER OF 12-18KTS WITH GUSTS UP TO 25-30KTS. HIGHER WINDS SPEEDS ARE POSSIBLE ABOVE 5KFT WITH A 50+KT LOW LEVEL JET TRANSVERSING THE REGION. PREV DISCUSSION... /ISSUED 153 PM EST SUN JAN 14 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... STRONG SHORT WAVE IN THE CENTRAL ROCKIES LIFTS INTO THE GREAT LAKES ON MONDAY AND PUSHES THE UPPER TROF THROUGH THE FORECAST AREA ON TUESDAY NIGHT. IN AN EFFORT TO NARROW DOWN WHEN BEST CHANCE OF RAIN WILL BE WILL REMOVE ANY CHANCE BEFORE NOON ON MONDAY. MODELS HAVE A SHORT WAVE COMING THROUGH ON MONDAY EVENING WITH Q-V FORCING AND SOME FRONTOGENESIS. THERE ARE WEST TO SOUTHWEST LOW LEVEL WINDS AND NO ISENTROPIC LIFT ALONG AND AHEAD OF THE FRONT HOWEVER...SO PRECIPITATION AMOUNTS WILL BE LOW. GUIDANCE IS STILL SHOWING A SPLIT IN RAINFALL AMOUNTS TO THE NORTHWEST AND SOUTH OF THE COUNTY WARNING AREA. BASING THE TIMING OF THE FRONT ON THE GFS. THE SURFACE FRONT COMES THROUGH THE COUNTY WARNING AREA ON MONDAY EVENING...WITH THE 850 MB FRONTAL PASSAGE ON TUESDAY MORNING. DEEP MOISTURE CROSSES THE FORECAST AREA BETWEEN 18Z MONDAY AND 06Z TUESDAY. THEN CLOUDS WILL CLEAR IN THE SOUTHEAST ON TUESDAY AND IN THE NORTHWEST ON WEDNESDAY MORNING. VERY DRY AIRMASS WILL THEN RESULT IN LITTLE TO NO CLOUD COVER THROUGH THURSDAY MORNING. HIGH PRESSURE NOW OVER THE NORTHERN ROCKIES WITH TEMPERATURES IN THE SINGLE DIGITS AND TEENS...AND SURFACE DEWPOINTS AROUND ZERO BUILDS IN BEHIND THE FRONT...CROSSES THE FORECAST AREA ON WEDNESDAY THEN MOVES OFFSHORE BY THURSDAY MORNING. THE ARCTIC AIRMASS WILL MODIFY BY THE TIME IT REACHES THE MID ATLANTIC STATES...BUT AREA IS STILL LOOKING AT TEMPERATURES BY TUESDAY AROUND 25 DEGREES COLDER THAN THE RECORD SETTING WARMTH TODAY. WILL HAVE STEADY OR FALLING TEMPERATURE TRENDS ON TUESDAY ALONG WITH GUSTY WINDS. SURFACE WINDS WILL START TO DIMINISH ON TUESDAY NIGHT AS THE HIGH APPROACHES. USED CURRENT TRENDS OF THE MAV GUIDANCE FOR LOWS TONIGHT AND HIGHS ON MONDAY. BIGGEST DEPARTURE FROM MAV NUMBERS WAS TO RAISE MAXIMUM TEMPERATURES FOR LEWISBURG. LONG TERM /THURSDAY THROUGH SUNDAY/... LARGE RANGE OF SOLUTIONS BETWEEN DIFFERENT MODELS BY THE END OF THE WEEK. OPERATIONAL GFS HAS MORE PROGRESSIVE SOUTHWEST UNITED STATES LOW AND STRONGER UPPER RIDGE IN THE SOUTHEAST WHILE ECMWF HAS A DEEPER TROF IN THE NORTHEAST. GFS ENSEMBLES ARE A COMPROMISE BETWEEN THESE SOLUTIONS WITH TROFING IN THE WEST AND ZONAL FLOW IN THE EAST THURSDAY AND FRIDAY WITH A LONG WAVE TROF DIGGING IN THE NORTHEAST UNTIED STATES BY SATURDAY. THIS WILL INFLUENCE HOW FAST ANY MOISTURE WILL RETURN IN THE WEST SIDE OF THE ARCTIC HIGH. ALSO INDICATES ANY ORGANIZED SYNOPTIC LIFT WILL BE IN THE REGION ON SATURDAY AND SUNDAY AS THE TROF DEEPENS IN THE NORTHEAST. WILL INTRODUCE LOW CHANCE OF PRECIPITATION ON FRIDAY AND SATURDAY. ALSO HAVE TEMPERATURES SLIGHTLY COOLER THAN MEX GUIDANCE FOR FRIDAY THROUGH SUNDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SHORT TERM...AMS va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 1021 PM PST SAT JAN 13 2007 .SYNOPSIS...A COLD AIR MASS WILL REMAIN OVER THE REGION THROUGH THE WEEKEND. HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH MONDAY NIGHT. THE NEXT CHANCE FOR LIGHT SNOW WILL BE ON TUESDAY AS A WEAKENING WEATHER DISTURBANCE MOVES THROUGH WASHINGTON. && .DISCUSSION... SNOW HAS CLEARED ALL OF THE SPOKANE FORECAST AREA...WITH THE POSSIBLE EXCEPTION OF THE CAMAS PRAIRIE AND THE NORTHEAST BLUE MOUNTAINS. THE 06Z RUC ANALYSIS SHOW THE 500MB SHORTWAVE TROUGH AXIS FROM NEAR BAKER CITY OREGON TO SALMON IDAHO. DESPITE WEAK LOW LEVEL MIXING BEHIND THE SHORTWAVE...EASTERN WASHINGTON AND FAR NORTHERN IDAHO HAVE CLEARED OUT. THE FOG PRODUCT SHOWS POCKETS OF LOW STRATUS DEVELOPING IN THE NORTHERN OKANOGAN VALLEY AS WELL AS ALONG THE COLUMBIA RIVER NEAR KETTLE FALLS. SOME OF THE FOG AND STRATUS MAY DEVELOP AS FAR SOUTH AS SPOKANE BY SUNDAY MORNING. ANY FOG AND STRATUS WILL BE PATCHY...AND SHOULD BE SHORT LIVED SINCE FORECAST SOUNDINGS SUGGEST MOISTURE IS CONFINED TO THE BOUNDARY LAYER. /GKOCH && .AVIATION...MAINLY VFR CONDITIONS ARE EXPECTED THROUGH 06Z MONDAY OVER CENTRAL AND EASTERN WASHINGTON...AS WELL AS THE NORTHERN IDAHO PANHANDLE. STRATUS IS EXPECTED TO CLEAR THE LEWISTON AREA BY 08Z AS THE SHORTWAVE THAT PRODUCED THE LIGHT SNOW IN THE AREA SINKS INTO EASTERN OREGON. SOME AREAS OF MVFR TO IFR VISIBILITIES ARE POSSIBLE WITH THE SUNRISE SUNDAY ESPECIALLY NEAR OPEN WATER SOURCES...BUT CONDITIONS SHOULD QUICKLY IMPROVE WITH DRY SURFACE HIGH PRESSURE OVER THE REGION. /GKOCH && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 1 18 6 21 10 24 / 10 0 0 0 0 20 COEUR D`ALENE 0 18 6 21 12 25 / 10 0 0 0 0 20 PULLMAN 3 19 7 23 15 26 / 50 0 0 0 0 20 LEWISTON 7 19 10 26 18 29 / 60 0 0 0 0 10 COLVILLE 0 16 0 19 7 22 / 0 0 0 0 0 20 SANDPOINT 2 17 3 20 7 22 / 10 0 0 0 0 20 KELLOGG 4 18 7 21 11 26 / 40 0 0 0 0 20 MOSES LAKE 7 21 9 24 13 27 / 10 0 0 0 0 20 WENATCHEE 9 21 10 24 14 28 / 0 0 0 0 0 20 OMAK -4 17 3 20 11 22 / 0 0 0 0 0 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 930 PM CST SUN JAN 14 2007 .UPDATE...LATEST RADAR AND SURFACE OBSERVATIONS INDICATED AN EXPANSIVE AREA OF SNOW ACROSS THE UPPER MISSISSIPPI VALLEY. FORCING MECHANISMS ASSOCIATED WITH SNOW MANIFESTED BY ISENTROPIC LIFT ON THE 285K SURFACE...UPPER LEVEL DIVERGENCE AND DEEP LAYERED Q-G CONVERGENCE. IN FACT...LATEST RUC AND NAM/WRF SUGGESTED HEAVIER SNOW BANDS ASSOCIATED WITH Q-G CONVERGENCE STILL TO COME DURING THE OVERNIGHT HOURS UNTIL ABATING AFTER ABOUT 09Z 15JAN07. CURRENT FORECAST APPEARS TO BE IN GOOD SHAPE FOR THE OVERNIGHT HOURS. NO UPDATES PLANNED AT THIS TIME...BUT PLEASE REFERENCE LATEST SHORT TERM FORECASTS AND WINTER WEATHER STATEMENTS. IN ADDITION...WE WILL BE SENDING A LIST OF LATEST SNOWFALL REPORTS IN A PUBLIC INFORMATION STATEMENT BEFORE 04Z THIS EVENING. THANKS TO MEDIA PARTNERS AND WEATHER OBSERVERS FOR THE REPORTS SO FAR THIS EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR WIZ029-WIZ032- WIZ033-WIZ034-WIZ041-WIZ042-WIZ043-WIZ044-WIZ053-WIZ054- WIZ055-WIZ061. SNOW ADVISORY UNTIL 12 PM CST MONDAY FOR WIZ017. MN...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR MNZ079-MNZ086- MNZ087-MNZ088-MNZ094-MNZ095-MNZ096. IA...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR IAZ008-IAZ009- IAZ010-IAZ011-IAZ018-IAZ019-IAZ029-IAZ030. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 244 PM CST SUN JAN 14 2007 .DISCUSSION...FORECAST FOCUS ON APPROACHING WINTER STORM. .SHORT TERM...HAVE UPGRADED TO WINTER STORM WARNING FOR TONIGHT AND MONDAY FOR ENTIRE CWA. CURRENT PRESENT WEATHER TRENDS CONTINUE TO BE IMPRESSIVE WITH STORM SYSTEM OVER CENTRAL US. EARLIER EVALUATION OF 12Z RUC/NGM/NAM MODELS APPEAR TO STILL BE OUTPERFORMING 12Z GFS PROG WITH REGARDS TO STRENGTH OF SYSTEM. THEREFORE HAVE LEANED TOWARD NAM SOLUTION AS MANY FACTORS CONTINUE TO COME INTO FOCUS FOR A DECENT WINTER STORM FOR SOUTHERN WISCONSIN. AMONG THEM...A DEEPER SURFACE LOW WITH A TRACK MOVEMENT MORE NORTHWEST OF PREVIOUS POSITIONS...STRONGER DEVELOPMENT OF 925 MILLIBAR AND 850 MILLIBAR LOW WITH TRACK OVER SWEET SPOT FROM EASTERN ILLINOIS TO NORTHWEST INDIANA...AND INFLUX OF MORE MOISTURE WITH PRECIPITABLE WATER VALUES APPROACHING 1 INCH OVER SOUTHEAST CORNER OF STATE. ALSO A STRONG JET...WITH POSSIBLE COUPLING OF UPPER JET MAXIMA...IN SOUTHWEST FLOW WITH IMPRESSIVE 250/300 MILLIBAR DIVERGENCE BULLSEYE OVER SOUTHERN WISCONSIN CENTERED AT 06Z MONDAY. BUFKIT DATA SHOWS LAKE CONTRIBUTION AND SOME INSTABILITY TO HELP ENHANCE SNOW AMOUNTS ALONG LAKE SHORE AREAS. THEREFORE HAVE BEEFED UP SNOWFALL AMOUNTS ALONG LAKE SHORE AREA. ALSO DECENT NORTHEAST SURFACE WINDS WILL CONTRIBUTE TO SOME BLOWING AND DRIFTING SNOW. BUFKIT DATA ALSO SHOWS EFFECT OF DRY SLOT ENTERING INTO SOUTHERN WISCONSIN AFTER 3AM TONIGHT. THIS DRY SLOT MAY RETARD SNOWFALL RATES FOR A TIME AS WELL AS PRODUCE SLEET OR FREEZING DRIZZLE. AT THE MOMENT THIS DRY SLOT WILL AFFECT MAINLY SOUTHERN PORTIONS OF THE CWA. COBB SNOW RATIOS AROUND 13:1 USED BUT TREND TOWARD 20:1 MONDAY AS COLDER AIR ENTRAINS INTO REGION. .LONG TERM...A MAINLY DRY AND COLD PERIOD WILL BE THE WEATHER RULE AS WEST TO NORTHWEST FLOW DOMINATES THE WEATHER PATTERN. ANY WEATHER SYSTEMS IN THIS FLOW WILL CONTAIN LIMITED MOISTURE. && .MKX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST MONDAY FOR WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058-WIZ059- WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-WIZ068-WIZ069- WIZ070-WIZ071-WIZ072. && $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 1018 AM CST SUN JAN 14 2007 .UPDATE...HAVE ISSUED WINTER STORM WATCH VALID FOR TONIGHT AND MONDAY FOR ENTIRE CWA. CURRENT PRESENT WEATHER TRENDS WITH STORM SYSTEM OVER CENTRAL US...12Z UPPER AIR ANALYSIS...AND EVALUATIONS OF 12Z RUC/NGM/NAM MODELS SHOW MANY FACTORS NOW COMING INTO FOCUS FOR A DECENT WINTER STORM FOR SOUTHERN WISCONSIN. AMONG NEW TRENDS IS A TREND TOWARD A DEEPER SURFACE LOW WITH A TRACK MOVEMENT MORE NORTHWEST OF PREVIOUS POSITIONS...STRONGER DEVELOPMENT OF 925 MILLIBAR AND 850 MILLIBAR LOW WITH TRACK OVER SWEET SPOT FROM EASTERN ILLINOIS TO NORTHWEST INDIANA...AND INFLUX OF MORE MOISTURE WITH PRECIPITABLE WATER VALUES APPROACHING 1 INCH OVER SOUTHEAST CORNER OF STATE. A STRONGER JET IN SOUTHWEST FLOW WITH IMPRESSIVE 250/300 MILLIBAR DIVERGENCE BULLSEYE OVER SOUTHERN WISCONSIN CENTERED AT 06Z MONDAY. QUICK EVALUATION OF BUFKIT DATA SHOWS LAKE CONTRIBUTION AND SOME INSTABILITY TO HELP ENHANCE SNOW AMOUNTS ALONG LAKE SHORE AREAS. WILL AWAIT 12Z GFS AND WATCH CURRENT WEATHER TRENDS FOR POSSIBLE UPGRADE TO WARNING LATER TODAY. && .PREV DISCUSSION... /ISSUED 314 AM CST SUN JAN 14 2007/ DISCUSSION...FORECAST FOCUS IS ON WEATHER EVENT TONIGHT AND EARLY MONDAY MORNING. MODELS HAVE COME INTO GOOD AGREEMENT WITH THIS NEXT SYSTEM...AS FAR AS MID AND HIGH LEVEL DYNAMICS ARE CONCERNED. THE SURFACE SYSTEM IS STILL EXPECTED TO TRACK WELL SOUTH OF WISCONSIN. HOWEVER...THE H850 BAROCLINIC ZONE IS NOW EXPECTED TO BE MAINLY ACROSS NORTHERN ILLINOIS...WITH WEAK SOME WEAK OVERRUNNING INTO SOUTHERN WISCONSIN. THE MOST SIGNIFICANT DYNAMICS WILL BE IN THE MID LEVELS WITH A PERIOD OF STRONG OMEGA CENTERED AROUND 06Z MONDAY. THERE WILL ALSO BE SOME PERSISTENT MODERATE FRONTOGENETIC FORCING BETWEEN H850 AND H700. THERE IS LITTLE EVIDENCE OF THETA-E RIDGING...BUT THERE SHOULD BE SOME H500 DIVERGENCE. THE PROBLEM IS THAT THE TEMPERATURE PROFILES ARE NEARLY ISOTHERMAL...RANGING FROM AROUND -5 TO -10 FROM THE SURFACE TO AROUND 12K FEET. BUFFY IS INDICATING THAT NO ICE CRYSTALS WILL BE PRESENT IN THE CLOUDS...AND TO CONSIDER FREEZING DRIZZLE. COBB WATER/SNOW RATIO IS EXPECTED TO BE AROUND 9:1 OVERNIGHT. HPC..GFS AND WRF 12 HOUR QPF ARE GENERALLY IDENTICAL...THE NAM IS A BIT HIGHER. USING A 13:1 PESSIMISTIC RATIO...I CAN ONLY GET AROUND 3 INCHES OVERNIGHT...AND ONLY 1 INCH OR SO MONDAY MORNING. I WILL HOLD OFF ON AN ADVISORY AT THIS TIME DUE TO LACK OF CONFIDENCE THAT THE SITUATION WILL DEVELOP. MKX WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .MKX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM 6 PM CST THIS EVENING THROUGH MONDAY AFTERNOON FOR WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058- WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-WIZ068- WIZ069-WIZ070-WIZ071-WIZ072. && $$ ZAJDEL/FOWLE wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1115 PM CST SAT JAN 13 2007 .UPDATE...CLOUDS PRODUCING ICE CRYSTALS TO SUPPORT MAINLY SNOW SHOULD BE GIVING WAY TO CLOUD TOP TEMPERATURES OF WARMER THAN MINUS 10C. THEREFORE...FREEZING DRIZZLE SHOULD BE MORE OF A THREAT IN THE SOUTHWEST CORNER OF WI AND ADJACENT PARTS OF NORTHEAST IOWA. LATEST RUC FORECAST SOUNDINGS...AS WELL AS KDMX RADAR IMAGE AND SURFACE OBSERVATIONS UPSTREAM OVER CENTRAL IOWA SUPPORT THIS. UPDATED APPROPRIATE ZONES AT 0445Z IN AFOREMENTIONED AREAS FOR WINTER WEATHER ADVISORY THROUGH THE OVERNIGHT HOURS TONIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 4 AM CST SUNDAY FOR WIZ054-WIZ055- WIZ061. MN...NONE. IA...WINTER WEATHER ADVISORY UNTIL 4 AM CST SUNDAY FOR IAZ029-IAZ030. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 321 AM CST TUE JAN 16 2007 .DISCUSSION... MAIN CONCERNS IN THE SHORT TERM WILL BE CLOUD COVER THROUGH TODAY... AND TEMPERATURES TONIGHT AS SOME OF THE COLDEST AIR SINCE EARLY DECEMBER MOVES INTO THE REGION. SHORT TERM...TODAY THROUGH FRIDAY... WEAK PVA AHEAD OF UPPER LEVEL TROUGH OVER IOWA HAS PROVIDED JUST ENOUGH WEAK LIFT IN A RATHER SHALLOW MOIST LAYER TO KEEP FLURRIES GOING OVERNIGHT ACROSS MUCH OF THE AREA. FLURRIES OR LIGHT SNOW SHOWERS WILL CONTINUE TO BE A THREAT THIS MORNING UNTIL H5 TROUGH AXIS CLEARS THE AREA. OBSERVATIONS SHOW VISIBILITIES ARE GENERALLY 7-10 MILES OR GREATER ACROSS THE AREA... SO ANY ACCUMULATION WILL BE VERY LIGHT FROM HERE ON OUT. THE VERY FINE AND DRY SNOW HAS BLOWN ABOUT QUITE A BIT OVERNIGHT... AND ROAD TRAFFIC HAS INDUCED MELTING/REFREEZING IN SOME LOCATIONS... SO DRIVERS SHOULD BE AWARE OF SLICK SPOTS. CLEARING LINE OF THE LOW CLOUDS IS ROUGHLY CO-LOCATED WITH THE MID LEVEL TROUGH AXIS... AND IT HAS BEEN VERY SLOW MOVING... STALLED OUT JUST WEST OF THE CWA ALL NIGHT. NAM/RUC CROSS SECTIONS AND LAYER RH/WIND PLOTS SUGGEST KEEPING THE LOW CLOUDS ACROSS MUCH OF THE CWA THROUGH NOON TIME... WITH GRADUAL CLEARING WEST OF I-55 EARLY IN THE AFTERNOON... WITH CLOUDS LINGERING UNTIL EARLY EVENING IN FAR EASTERN ILLINOIS. SO WHILE IT IS TEMPTING TO GO WITH A MORE OPTIMISTIC SKY FORECAST WITH THE CLEARING LINE SO CLOSE... WILL KEEP THINGS PESSIMISTIC. SATELLITE OBS OVER MISSOURI ACTUALLY SUGGEST THE CLOUDS ARE REDEVELOPING IN BANDS PARALLEL WITH THE LOW LEVEL FLOW... THESE BANDS EVEN SHOW UP WELL IN 88D DATA FROM KLSX. CLEARING WILL COME IN OVERNIGHT... BRINGING SOME OF THE COLDEST WEATHER WE HAVE SEEN SINCE EARLY DECEMBER... AND CLEARLY THE COLDEST OF THE YEAR SO FAR. RECENT TRACES AND MINOR ACCUMULATIONS OF DRY SNOW ARE NOT EXPECTED TO HAVE MUCH IMPACT ON LOW TEMPS TONIGHT. WINDS WILL BE LIGHTEST WEST OF I-55 WHERE THE SFC RIDGE AXIS WILL SET UP. UPSTREAM TEMPERATURES THIS MORNING OVER EASTERN IOWA HAVE BEEN MORE INFLUENCED BY THE LIGHT SNOW PACK IN THOSE REGIONS... AND THUS DO NOT EXPECT OUR TEMPERATURES TONIGHT TO BE QUITE SO LOW. EXPECT A SLOW WARMING TREND WED-THU AS HIGH PRESSURE SETTLES OFF TO OUR EAST. HAVE DECREASED MAX TEMPS ON WEDNESDAY AS HIGH PRESSURE REMAINS MORE OR LESS OVERHEAD THROUGH THE AFTERNOON... WITH SFC WINDS NOT REALLY SHIFTING UNTIL EVENING. ANY WAA JUST ALOFT WILL LIKELY HAVE A HARD TIME MIXING DOWN TO THE SFC WITH STRONG SUBSIDENCE INVERSION IN PLACE. A WEAK CLIPPER SYSTEM WILL APPROACH FRIDAY INTO FRIDAY NIGHT... AND WHILE SOME SCATTERED FLURRIES CANNOT BE COMPLETELY RULED OUT... CHANCES ARE STILL TOO LOW TO MENTION IN THE FORECAST THIS FAR OUT. THE GFS IS NOW IN AGREEMENT WITH THE ECMWF IN DEFLECTING THE SECOND ARCTIC INTRUSION BEHIND THE CLIPPER WELL TO OUR EAST... BUT TEMPS WILL DIP AGAIN BY THE WEEKEND... WITH SOME REMAINING CLOUD COVER AND A COOL NORTHWEST WIND. HOWEVER... TEMPERATURES WILL BE ONLY A LITTLE BELOW NORMAL IN THIS TIME FRAME. LONG TERM...SATURDAY THROUGH MONDAY... LONGER RANGE SOLUTIONS SUGGEST WE WILL REMAIN IN THIS COOLER/NEAR NORMAL PATTERN EVEN OUT THROUGH DAY 10... AS H5 LOW REMAINS ANCHORED OFF BAFFIN ISLAND... WITH THE MEAN LONGWAVE TROUGH POSITION ACROSS THE NORTHEASTERN CONUS. THE +72 HR AND +240 HR ECMWF H5 PLOTS... VALID THIS AND NEXT THURSDAY NIGHT... LOOK ALMOST IDENTICAL. NEXT CHANCE FOR PRECIP WILL COME TOWARDS SUN/MON AS A CUTOFF LOW CURRENTLY PINCHING OFF OVER THE DESERT SOUTHWEST... EJECTS EASTWARD. WITH TEMPERATURES NEAR OR JUST BELOW NORMAL... WINTRY PRECIP MAY BE A THREAT... BUT AT THIS POINT NO MAJOR STORMS APPEAR TO BE ON THE HORIZON. WILL NEED TO KEEP AN EYE ON EJECTING CUTOFF LOW TO SEE IF IT CAN MANAGE TO PHASE WITH SOME NORTHERN STREAM ENERGY WHICH MAY BE MORE CONDUCIVE TO SFC CYCLOGENESIS. BEYOND THAT... WE REMAIN IN THE SAME FAMILIAR PATTERN AS THIS WEEK... WITH PERIODIC INTRUSIONS OF COLD AIR MAINLY SCRAPING BY TO OUR EAST. THE GFS IN THE LONGER TERM IS QUITE A BIT COLDER FOR US THAN THE ECMWF AS IT BRINGS DOWN THE ARCTIC AIR ACROSS THE MIDWEST INSTEAD OF THE EAST COAST... BUT THE GFS EARLIER PREDICTED THE SAME THING FOR THIS WEEK... AND ONLY IS JUST NOW CATCHING UP WITH THE ECMWF. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HARDIMAN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 AM EST TUE JAN 16 2007 .AVIATION... LAKE EFFECT SNOW ONGOING AT ISSUANCE TIME AND REGIONAL RADARS SHOWING INTENSIFICATION BEGINNING WITH COLDEST TEMPS COMING DOWN THE LAKE. EXPECT THIS TREND TO CONTINUE THROUGH THE NIGHT WITH MAX INTENSITY BETWEEN 09Z AND 15Z. WILL HAVE TO MONITOR BAND MOVEMENT AND OBS FOR POSSIBLE AMENDMENTS FOR LOWER VIS. AT KFWA...A BREAK WITH VFR CONDITIONS BUT UPSTREAM MVFR CIGS AND VIS WITH SOME SNOW SHOWERS SHOULD MOVE SOUTH INTO THE AIRPORT AREA NEXT FEW HOURS. MAIN LAKE EFFECT BAND MAY STAY WEST OF KFWA BUT WILL BE CLOSE WITH CYCLONIC CURVATURE ON TUESDAY. KEPT A MVFR TEMPO GROUP FOR NOW. A NOTE FOR THOSE LOOKING AT MESOSCALE MODEL OUTPUT FOR THIS LAKE EFFECT SNOW EVENT...SUCH AS THE NAM-WRF...CANADIAN REGIONAL GEM...OR THE FSL RUC. WE HAVE SEEN A SYSTEMATIC BIAS OF MESOSCALE MODELS BEING TOO FAR WEST WITH BAND PLACEMENT IN SINGLE BAND SITUATIONS. THE VAST MAJORITY OF THE TIME THE LAKE EFFECT SNOW BAND VERIFIES 10 TO 20 NM EAST OF THE MESOSCALE MODEL BAND LOCATION...ASSUMING THE MODEL HAS A GOOD HANDLE ON THE SYNOPTIC BACKGROUND FLOW. && .SHORT TERM... TONIGHT AND TUESDAY ...MAJOR LAKE EFFECT SNOW EVENT TONIGHT INTO TUESDAY... FORECAST CONCERN IN THE SHORT TERM REVOLVES AROUND LAKE EFFECT SNOW POTENTIAL LATER THIS EVENING THROUGH TUE AFTERNOON. FIRST...OUTSIDE OF LAKE EFFECT AREAS A BAND OF SNOW IS MOVING THROUGH THE N/NW PORTION OF THE CWA THIS AFTERNOON ALONG FIRST OF SEVERAL SECONDARY COLD FRONTS. THE TRUE ARCTIC FRONT LIES OVER SOUTHERN WISCONSIN AND CENTRAL LOWER MICHIGAN WITH REGIONAL RADARS SHOWING ANOTHER BAND OF ENHANCED SNOW ALONG AND BEHIND THIS FEATURE. ALSO A LARGE AREA OF LIGHT SNOW ASSOCIATED WITH DECAYING DEFORMATION AXIS UPSTREAM FROM NORTHERN ILLINOIS INTO LOWER MICHIGAN. GIVEN LOOK OF UPSTREAM RADARS AND EXPECTED PASSAGE OF MID LEVEL TROUGH AXIS AND ASSOCIATED LIFT... MAY SEE A GENERAL LIGHT SNOWFALL ACROSS MOST OF THE CWA TONIGHT. WILL PROBABLY END UP GOING WITH LOW LIKELY POPS AND A COATING OF ACCUMS IN MOST AREAS...EXCEPT FOR THE FAR SOUTH. NOW FOR THE LAKE EFFECT. FORECAST SURFACE PRESSURE FIELDS SHOW A CLASSIC PATTERN RECOGNITION FOR A BIG SOUTHERN LAKE MICHIGAN EVENT WITH A 1040+MB ARCTIC HIGH BUILDING SOUTH DOWN THE PLAINS. UPSTREAM RADARS SHOWING HEALTHY BANDS OF LAKE EFFECT SNOW DEVELOPING ON NORTHERLY FETCH OF LAKE SUPERIOR AND ANOTHER OFF GREEN BAY AFFECTING THE DOOR PENINSULA. LAST FEW RUNS OF THE NAM-WRF AND THE FSL EXPERIMENTAL 13KM RUC HAVE BEEN REASONABLY CONSISTENT IN DEVELOPING A WELL DEFINED SINGLE BAND TONIGHT DOWN THE LONG AXIS OF LAKE MICHIGAN. INSTABILITY IS VERY GOOD WITH LAKE INDUCED CAPES EXCEEDING 500J/KG AND EQUILIBRIUM LEVELS ABOVE 700MB. CLOUD BEARING LAYER AND ASSOCIATED MODEL INDUCED OMEGA SHOWING A NICE BULLSEYE SIGNATURE INTERSECTING THE FAVORED DENDRITIC SNOW GROWTH ZONE. MESOSCALE MODELS ALSO SUGGESTING AN UPSTREAM CONNECTION TO LAKE SUPERIOR FOR AWHILE TONIGHT...WHICH IS A CLASSIC HALLMARK OF OUR BIG EVENTS AT THE SOUTH END OF LAKE MICHIGAN. CONVERGENCE ALREADY BEGINNING TO DEVELOP DOWN THE AXIS OF THE LAKE AS NOTED IN SURFACE OBS ALONG THE E AND W SHORELINES...AND NAM-WRF STRENGTHENS LOW LEVEL CONVERGENCE FIELD AS IT ARCS CYCLONICALLY INTO NW INDIANA AND SW LOWER MICHIGAN. ALL SIGNS POINT TOWARDS THE POTENTIAL OF A MAJOR LAKE EFFECT SNOW EVENT...WHICH HAS BEEN A RARITY AROUND HERE THE PAST FEW SEASONS GIVEN THE WARM TEMPERATURES. THE FORECAST DETAILS...WILL BE UPGRADING THE LES WATCH TO A WARNING FOR BERRIEN...CASS...ST JOSEPH...AND ELKHART COUNTIES. THE REMAINDER OF THE COUNTIES IN THE WATCH WILL BE UPGRADED TO AN ADVISORY. MAY SEE A RATHER INTENSE BAND ACROSS PARTS OF LAPORTE...STARKE... MARSHALL...AND KOSCIUSKO COUNTIES...HOWEVER EXPECT THE BAND TO REMAIN TRANSIENT THROUGH THESE COUNTIES AND NOT STAY OVER ONE SPOT LONG ENOUGH TO DROP WARNING CRITERIA. IF IT BECOMES APPARENT THAT THE BAND WILL GO STATIONARY FOR SEVERAL HOURS OVER ONE OF THESE COUNTIES THAN AN UPGRADE MAY BE NEEDED. EXPECT THE MAJOR SINGLE BAND TO BREAK APART INTO MULTIPLE BANDS...WEAKEN...AND SPREAD EAST ON TUE AFTERNOON AS FLOW BACKS AND SYNOPTIC SCALE SUBSIDENCE INCREASES. STORM TOTALS OF 6 TO 12 INCHES ARE POSSIBLE IN SOME LOCATIONS IN THE WARNING COUNTIES...WITH LOCAL AMOUNTS OF OVER A FOOT POSSIBLE WHERE BANDS PERSIST THE LONGEST. && .LONG TERM... TUESDAY NIGHT THROUGH MONDAY RATHER DRAMATIC PATTN SHIFT HAS COMMENCED W/DEEP NEG HGT ANOMALY FORECAST TO DVLP ACRS ERN CANADA BY THIS WEEKEND AND OF WHICH CONSIDERING THE BACKDROP OF NAO/AO TELECONNECTIONS GOING SLIGHTLY NEGATIVE SUGGEST A CONTD INFLUX OF ARCTIC AIR INTO THE NC/NE US AND ESP SO EARLY NXT WEEK IF PROGGED CROSS POLAR FLW DVLPS AS SUGGESTED PER GFS ENSEMBLES. MAIN STORY IS ARRIVAL OF TRUE WINTERTIME AIRMASS W/TEMPS AOB NORMAL FOR A CHANGE THIS WEEK AND SNOW POTENTIAL W/SHARPENING ERN US TROUGHING AND NXT ARCTIC INTRUSION BY WEEKS END. COLDER SLANT OF 12Z GFS PREFERRED ESP IN LIGHT OF SHRT TERM LK EFFECT SNOW POTENTIAL AND SUPPRESSION OF ANY SIG SRN STREAM DVLPMNT THIS WEEK BOTH OF WHICH KEEPS SEASONABLY COLD AIR IN PLACE. DIFFS AMG MED RANGE GUIDANCE REMAIN W/DEPTH/INTENSITY OF SHARPENING NRN STREAM TROUGH FRI/SAT AND MORE IMPORTANTLY LL FLW TRAJECTORIES DOWNSTREAM OF LK MI. CURRENT GRIDS HAVE THIS IN MIND W/LOW CHC POPS FAVORED FRI-SAT AND LEFT AS IS. OTHERWISE BIGGER ISSUES CROP UP W/HANDLING OF SRN STREAM CUTOFF LATE THIS WEEKEND AND EARLY NXT WEEK W/BULK OF MED RANGE GUIDANCE SUGGESTING THIS SYS WILL KICK OUT INTO THE PLAINS LATE THIS WEEKEND AHD OF RENEWED NRN STREAM FORCED WRN TROUGH DVLPMNT...AND W/COLD AIR IN PLACE DOWNSTREAM THINGS MAY GET INTERESTING SUNDAY AND MONDAY W/AT LEAST LOW CHC POPS WARRANTED FOR MAINLY SNOW THEN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ004-INZ005. LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY FOR INZ003-INZ012. LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 4 PM EST TUESDAY FOR INZ014-INZ016. MI...LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 4 PM EST TUESDAY FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...HITCHCOCK/LASHLEY LONG TERM...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EST TUE JAN 16 2007 .DISCUSSION... TAKING A LOOK AT THE WATER VAPOR IMAGERY THIS MORNING...MUCH OF THE NATION WAS RELATIVELY DRY. IN GENERAL...ALL BUT THE EASTERN THIRD OF THE NATION WAS UNDER THE INFLUENCE OF HIGH PRESSURE. THERE WERE THREE SURFACE LOWS OF NOTE THIS MORNING. THE FIRST WAS THE EXITING LOW PRESSURE SYSTEM...CENTERED OVER JUST OFF THE NEW ENGLAND COAST...WITH A COLD FRONT STRETCHING THROUGH THE CAROLINAS AND NORTHWESTERN FLORIDA. THE SECOND...SLIGHTLY WEAKER LOW WAS SITUATED OVER THE NORTHWEST TERRITORIES UP IN CANADA. THIS FEATURE HAD A WARM FRONT DROPPING SOUTH THROUGH SASKATCHEWAN AND EASTERN MONTANA. WARMER TEMPERATURES WERE NOTED ACROSS NORTHERN MONTANA. FOR EXAMPLE...THE 09Z TEMPERATURE AT CUT BANK MONTANA WAS 28 DEGREES...WHILE CLOSER TO HOME THE TEMPERATURE WAS -16 AT INTERNATIONAL FALLS. LOOKING HIGHER UP INTO THE ATMOSPHERE...AND THE WATER VAPOR IMAGERY AND RUC...THE MID LEVEL TROUGH WAS SET UP FROM EASTERN LAKE SUPERIOR THROUGH THE SOUTHERN TIP OF THE UPPER PENINSULA...AND DOWN THROUGH IOWA...ALL THE WAY THROUGH SOUTHERN ARIZONA. CONTINUE TO BE CONCERNED WITH LAKE EFFECT SNOW ACROSS OUR THE CENTRAL AND EASTERN LAKE SUPERIOR SHORELINE TODAY. THE BANDS OF SNOW HAVE BEEN CONTINUING THE SLOWLY SHIFT EASTWARD OVERNIGHT AS WINDS HAVE BECOME MORE NORTHWESTERLY...INCREASING THE CONVERGENCE ACROSS THIS AREA. WAS ORIGINALLY CONCERNED WITH THE AMOUNT OF DRY AIR THAT WILL COME INTO THIS AREA WITH OF CENTRAL...WESTERN...AND NORTHERN LAKE SUPERIOR CLOUD FREE EARLIER THIS MORNING. FURTHER TO OUR WEST...DEW POINTS ARE IN THE UPPER TEENS TO MID 20S BELOW ZERO. ACROSS THE CWA DEW POINTS WERE STILL IN THE SINGLE DIGITS ABOVE ZERO. EVEN WITH THIS DRIER AIR FILTERING IN...THE NNW TO SSE CLOUDS HAVE DEVELOPED FAIRLY NICELY OVER THE PAST SEVERAL HOURS ACROSS THE EASTERN HALF OF THE LAKE. THE BETTER FETCH FOR LAKE EFFECT WAS ALSO EXPECTED TO OFFSET SOME OF THIS DRY AIR. EVENING SHIFT DID HOIST ADVISORIES FOR ALGER COUNTY EASTWARD THOUGH THIS EVENING. 3-5KFT INVERSION HEIGHTS...GOOD MOISTURE AROUND THE SNOW GROWTH REGION SHOULD ALLOW FOR ADVISORY CRITERIA THROUGH THIS EVENING. WARM AIR WILL SURGE EASTWARD INTO THE UPPER PENINSULA DURING THE DAY WEDNESDAY AS THE WARM FRONT OVER NORTHEASTERN MONTANA SWINGS OUR WAY AND THE 500MB RIDGE SLIDES OVERHEAD. 850MB TEMPERATURE SHOULD RISING TO THE -1 TO -3 RANGE BY 00Z THURSDAY. WITH THIS SAID...AM HESITANT TO DECREASE CURRENT FORECAST TEMPERATURES ANY...EVEN GIVEN SLIGHTLY COOLER TEMPS FROM THE GFS/MAV WITH MORE CLOUDS ANTICIPATED. SO...FEW CHANGES WERE MADE TO TEMPS FOR MID WEEK. ALSO TO HINDER TOO MANY CHANGES TO THE FORECAST...THE GFS AND NAM ARE BOTH NOT FAVORED FOR MID WEEK AND BEYOND...WITH A QUICKER UKMET/ECMWF SOLUTION PREFERRED. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-007-085. && $$ KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1156 PM EST MON JAN 15 2007 .AVIATION... VFR CONDITIONS AT MBS WILL SPREAD SLOWLY SOUTHWARD TOWARD FNT OVERNIGHT AND REACH DETROIT FOR A WHILE AROUND SUNRISE. VFR WILL THEN FILL BACK IN TO MVFR DURING THE DAY TIME BEFORE SCATTERING OUT TO VFR AGAIN AROUND MID AFTERNOON. AT WORST, A BROKEN VFR CEILING WILL SCATTER OUT BY TUESDAY EVENING. PATCHES OF LIGHT SNOW AND FLURRIES OVER SOUTHERN LOWER MICHIGAN WERE STRONGLY DEPENDENT ON LOW LEVEL CONVERGENCE ASSOCIATED WITH THE TROUGH SHOWN ON THE SURFACE ANALYSIS. THIS ACTIVITY WILL CONTINUE TO WEAKEN OVERNIGHT AS THE TROUGH FILLS AND HIGH PRESSURE BUILDS MORE STRONGLY INTO THE REGION. && .PREV DISCUSSION...ISSUED 952 PM EST MON JAN 15 2007 UPDATE... THE AREA OF LIGHT SNOW OVER SOUTHERN LOWER MICHIGAN WAS WEAKENING AS THE MID LEVEL DEFORMATION SHEARED APART WHILE SLIDING EASTWARD. EXPECT THIS TREND TO CONTINUE AND LEAVE BEHIND COLD NORTHERLY LOW LEVEL FLOW THAT WILL HEIGHTEN LAKE EFFECT POTENTIAL IN THE THUMB FOR A FEW HOURS. THE LATEST OBSERVATIONS SHOWED A NICE AREA OF WIND CONVERGENCE COMING INTO THE THUMB BETWEEN GRAVELLY SHOAL AND HARBOR BEACH. COMBINE THIS WITH COLD ADVECTION TAKING 850 MB TEMPS DOWN TO ABOUT -15C BY 06Z AND EQUILIBRIUM LEVELS RISING TO ABOUT 750MB/7000 FEET AND THE INITIAL SET UP LOOKS GOOD FOR OUR GOING FORECAST. ONE TO 3 INCHES APPEARS ON TARGET CONSIDERING THE BRIEF NATURE OF THE EVENT WITH THE WINDS TURNING TOWARD THE NW BY 09Z DRIVING LAKE EFFECT WELL OFF SHORE BY 12Z. OUR FORECAST UPDATE WILL BE ISSUED CLOSER TO MIDNIGHT TO LOWER POPS OVER INLAND AREAS DURING THE OVERNIGHT ONCE THE LIGHT SYSTEM SNOW DIMINISHES ADEQUATELY. WE WILL ALSO REVISIT ACCUMULATION IN THE THUMB BASED ON THE LATEST RADAR AND WIND TRENDS. PREV DISCUSSION...ISSUED 329 PM EST MON JAN 15 2007 SHORT TERM...TONIGHT AND TUESDAY WITH OUR RECENT STORM TRACKING EAST OF THE GREAT LAKES...RESIDUAL DEFORMATION AXIS OF SNOW WILL MOVE ACROSS THE REGION THIS EVENING. CROSS SECTIONS NICELY DEPICT THIS DEFORMATION ZONE CENTERED BETWEEN 600-700MB WITH VISIBILITIES UNDER THE BAND OF SNOW DROPPING TO LESS THAN 1 MILE. IN FACT...SOME LAKE HURON CONTRIBUTION IS NOTED WITH A NARROW BAND OF SNOW COMING DOWN ACROSS SAGINAW BAY INTO MBS WITH 1/4 MILE VISIBILITY. LATEST RUC INCLUDING THE 12Z MODEL SUITE SUGGEST THE 1000-850MB WIND WILL BACK TOWARD THE NORTH THIS EVENING AS THIS DEFORMATION AXIS SWINGS SOUTH-SOUTHEAST ACROSS THE STATE. SPECIFIC HUMIDITIES ARE RUNNING AROUND 1 G/KG AND ACCUMULATIONS COULD ADD UP TO ANOTHER 1 INCH NORTH OF M59 THIS EVENING. FURTHER SOUTH...WITH THE BOUNDARY LAYER BECOMING MORE NORTHERLY...EXPECT SOME DOWNSLOPING INFLUENCES TO REDUCE THE SNOWFALL AMOUNTS AND DEFORMATION AXIS WEAKENING AS THE SURFACE TROUGH AND UPPER LEVEL TROUGH SWING SOUTHEAST OF THE STATE. THEN THE REAL COLD ADVECTION TAKES SHAPE TONIGHT WITH CONCERN SHIFTING TOWARD LAKE EFFECT SNOW FOR PORTIONS OF THE THUMB. BOTH THE NAM AND GFS ARE IN RATHER GOOD AGREEMENT WITH THE 1000-850MB FLOW WHICH IS RATHER PERSISTENT (360 DEGREES) FOR MOST OF THE NIGHT. TOWARD 09Z-12Z...FLOW BACKS A LITTLE MORE TAKING THE BAND OFFSHORE BUT STILL TOUCHING THE M10 CORRIDOR IN HURON COUNTY. INVERSION HEIGHTS CLIMB...PER BUFKIT PROFILES...FROM NEAR 850MB TO BETWEEN 800-750MB WITH LAKE INDUCED CAPES CLIMBING TOWARD 300 J/KG AND LAKE DELTA T/S INTO THE MIDDLE TEENS CELSIUS. 925MB CONVERGENCE AND OMEGA FIELDS LOOK RATHER IMPRESSIVE ACROSS HURON...SANILAC AND TOUCHING NORTHEAST ST CLAIR COUNTY OVERNIGHT SO ADDITIONAL SNOWFALL IS EXPECTED. LOCAL DECISION TREE SUGGESTS ANOTHER 2-4"/12HRS BUT WITH THE BAND MOVING OFFSHORE...WILL CUT THOSE VALUES TO ANOTHER 1-3" AND MENTION BRIEF PERIODS OF HEAVY SNOW IN THE FORECAST/GRIDS. WEATHER DOES QUIET DOWN ON TUESDAY WITH A COLD NORTHERLY FLOW AND MOISTURE DECREASING. THIS SHOULD ALLOW FOR SOME SUNNY BREAKS YET THAT COULD HELP STEEPEN THE LOW LEVEL LAPSE RATES...AND WOULD NOT BE SURPRISED TO SEE SOME LIGHT SNOW SHOWERS MOVING ACROSS THE CWA. WILL KEEP THE LOW POPS FOR MOST AREAS AWAY FROM LAKE HURON...AS LAKE BAND COULD STILL IMPACT THE M10 CORRIDOR IN HURON COUNTY. TEMPERATURES WILL BE QUITE CHILLY (OR SEASONABLE) TONIGHT AND TUESDAY WITH LOWS TONIGHT DROPPING BACK INTO THE TEENS. ON TUESDAY WITH 850MB TEMPS INTO THE NEGATIVE MID TEENS...WE WILL BE LUCKY TO TOUCH 30F. LONG TERM... MODIFYING TREND WEDNESDAY AND THURSDAY BEFORE ANOTHER SURGE OF ARCTIC AIR ARRIVES BY FRIDAY. MEDIUM RANGE MODELS (12Z EUROPEAN/CANADIAN GLOBAL/GFS) IN DECENT AGREEMENT THROUGH THE FIRST HALF OF THE WEEKEND. AMPLIFIED UPPER LEVEL RIDGE TO BUILD INTO THE CENTRAL GREAT LAKES ON WEDNESDAY. TUESDAY NIGHT IS SHAPING UP TO BE THE COLDEST NIGHT OF THE SEASON THUS FAR AS 1040+ MB HIGH SETS UP OVER THE NORTHERN OHIO VALLEY WEDNESDAY MORNING. HOWEVER...RELATIVELY WARM GROUND AND LACK OF SIGNIFICANT SNOW DEPTH OVER MUCH OF SOUTHEAST MICHIGAN SHOULD FACTOR IN. WENT FAIRLY CLOSE TO GFS MOS GUIDANCE...UPPER SINGLE NUMBERS TO LOWER TEENS. IF THIS WAS A MORE TYPICAL WINTER...WOULD HAVE EXPECTED MINS DOWN AROUND ZERO. TRAILING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA IS FORECASTED TO EJECT OFF TO THE NORTHEAST...AS MORE VIGOROUS UPPER WAVES OVER THE GULF OF ALASKA AND ALASKA EVENTUALLY CARVE OUT ANOTHER TROUGH OVER THE NORTH CENTRAL CONUS ON THURSDAY. SOME TIMING DIFFERENCES WITH THE SOUTHERN WAVE...ALONG WITH MEAGER MOISTURE INDICATED BY MODELS ON THURSDAY. NONE-THE-LESS...IT IS A DECENT WAVE AND POSSIBLE HELP FROM LAKE MICHIGAN...PREFER TO CARRY A LOW CHANCE OF LIGHT SNOW OR FLURRIES BY THURSDAY AFTERNOON. THERE IS SOME SEMBLANCE OF AN 850-700 MB THETA-E RIDGE/WEAK MOISTURE TRANSPORT MOVING THROUGH AS WELL. A LITTLE BETTER CHANCE OF SNOW SHOWERS THURSDAY NIGHT AND ESPECIALLY FRIDAY WITH COLD FRONT SLIDING THROUGH THURSDAY NIGHT AND LAKE EFFECT LIKELY KICKING IN BY FRIDAY AS 850 MB TEMPS DROP TO -16 TO -18 C. ARCTIC AIRMASS LOOKS TO BE SLOW TO PUSH EAST ON SATURDAY...WITH A CONTINUED CHANCE OF SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...SAGINAW BAY UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...BT SHORT TERM...BGM LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 254 AM CST TUE JAN 16 2007 .DISCUSSION...TEMPERATURES REMAIN THE PRIMARY CHALLENGE OVER THE NEXT SEVERAL DAYS. ONE WORD CAN PRETTY MUCH SUM UP CURRENT CONDITIONS...COLD. A 1036MB SURFACE HIGH PARKED OVER THE REGION AND ASSOCIATED CLEAR SKIES AND CALM WINDS HAVE TEAMED UP WITH THE FRESH SNOW COVER TO PRODUCE BITTERLY COLD TEMPERATURES. TEMPERATURES ACROSS THE CWA CURRENTLY RANGE FROM 1 ABOVE TO 12 BELOW ZERO. EARLY MORNING WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW THAT THE UPPER WAVE THAT BROUGHT US THE LAST ROUND OF ACTIVE WEATHER HAS SLID EAST...WITH A STRAIGHT NORTHERLY FLOW PREVAILING ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS BETWEEN THE DEPARTED WAVE AND A SHORTWAVE RIDGE OVER THE NORTHERN ROCKIES. STRONG SUBSIDENCE IS FIRMLY IN PLACE OVER THE NORTHERN AND CENTRAL PLAINS...AS EVIDENCED BY THE 1036MB SURFACE HIGH AND CLEAR SKIES. A FAIRLY QUIET WEATHER PATTERN WILL CONTINUE ACROSS THE AREA THE NEXT FEW DAYS. WEAK SOUTHWEST RETURN FLOW DEVELOPS BY AFTERNOON AS THE SURFACE HIGH PUSHES SOUTHEAST WHILE UPPER RIDGING BUILDS EAST INTO THE REGION. WE/LL ALSO SEE AMPLE SUNSHINE AGAIN TODAY. HOWEVER...STILL EXPECT ONLY MARGINAL IMPROVEMENT IN TEMPERATURES GIVEN A VERY COLD START TO THE DAY...SNOW COVER...LIGHT WINDS...AND VERY LIMITED MIXING. H85 TEMPS DO WARM SEVERAL DEGREES FROM YESTERDAY...BUT IT WILL BE DIFFICULT TO REALIZE MUCH OF THIS AT THE SURFACE GIVEN LITTLE MIXING. HAVE STAYED WAY BELOW MOS GUIDANCE AND MODEL 2M TEMPS WHICH ARE CURRENTLY RUNNING AROUND 10 DEGREES TOO WARM COMPARED TO ACTUAL TEMPS. CLEAR SKIES CONTINUE INTO TONIGHT AND ALTHOUGH IT WILL BE ANOTHER COLD ONE...SOUTHERLY SURFACE WINDS STAY UP SOME WHICH SHOULD KEEP MIN TEMPS NOTABLY WARMER THAN CURRENT READINGS. THE UPPER FLOW TURNS SOUTHWEST ON WEDNESDAY AS A SHORTWAVE TRACKS ACROSS THE CENTRAL ROCKIES AND PLAINS. MEANWHILE LOW-LEVEL SOUTHERLY FLOW INTENSIFIES IN A TIGHTENING GRADIENT BETWEEN A DEEPENING LEE TROUGH AND SURFACE HIGH TO THE EAST. ASSOCIATED WARM AIR ADVECTION SHOULD BE SUFFICIENT TO PUSH DAYTIME TEMPS INTO THE 20S F. THE WAVE WILL BRING SOME INCREASE IN CLOUDS BUT NOTHING IN THE WAY OF PRECIP. A CLIPPER SYSTEM THEN SENDS A COLD FRONT THROUGH THE CWA WEDNESDAY NIGHT. SHOULD SEE AN AN ASSOCIATED INCREASE IN CLOUDS...WHICH WILL HELP HOLD TEMPS UP COMPARED TO PREVIOUS COUPLE OF NIGHTS. COLD AIR ADVECTION WILL STALL THE GRADUAL WARMING TREND...WITH TEMPS ON THURSDAY EXPECTED TO REMAIN IN THE MID 20S TO LOWER 30S FOR HIGHS. THIS SYSTEM CONTINUES TO LOOK MOISTURE STARVED SO WILL MAINTAIN THE DRY FORECAST WEDNESDAY NIGHT AND THURSDAY. NO NOTEWORTHY CHANGES WERE MADE TO THE EXTENDED...BUT THE MAIN FEATURE OF INTEREST DURING THIS PERIOD IS ANOTHER SOUTHWEST CUTOFF LOW WHICH COULD BE A PLAYER IN OUR WEATHER OVER THE WEEKEND. FORECAST TRACKS FROM LATEST OPERATIONAL MODEL RUNS SUGGEST SOUTHERN PORTIONS OF THE CWA AND POINTS SOUTH WOULD SEE THE GREATEST IMPACT FROM THIS SYSTEM...BUT ENSEMBLE DATA SHOWS A LOT OF UNCERTAINTY EXISTS WITH THE EVOLUTION OF THIS SYSTEM AS WOULD BE EXPECTED AT THIS POINT. THIS WILL BEAR CLOSE WATCHING IN THE DAYS TO COME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ KB ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 630 AM EST TUE JAN 16 2007 .AVIATION... FOCUS REMAINS ON LAKE EFFECT SNOW BAND AT KSBN. IMPRESSIVE BAND JUST WEST OF KSBN BUT MAKING ITS WAY BACK EAST. THIS WILL LIKELY CONTINUE INTO THE EARLY AFTERNOON AS NAM12 925MB PLUME ANALYSIS KEEPS GOOD OMEGA OVER KSBN AREA. REGIONAL RADAR MOSAICS SHOWS MEANDERING BAND DOWN THE AXIS OF LAKE MICHIGAN. EXPECT OCCASIONAL MODERATE SNOW THROUGH THE MORNING WITH IMPROVING CONDITIONS DURING THE AFTERNOON. AT KFWA...DRIER AIR TRYING TO WORK IN. CYCLONIC CURVATURE OF LAKE EFFECT BAND MAY OCCASIONALLY GET INTO THE SITE. HAVE BEEN A BIT MORE OPTIMISTIC THOUGH GIVEN LATEST RADAR TRENDS AND PLUME MOVING MORE SOUTH THAN SOUTHEAST. && .SHORT TERM... TODAY AND TONIGHT... ...SIGNIFICANT LAKE EFFECT SNOW ONGOING... AS EXPECTED...TYPE I LAKE EFFECT SNOW BAND HAS SET UP DOWN THE LONG AXIS OF LAKE MICHIGAN. AT 08Z...GOES 3.9-11 MICRON SHOWS IMPRESSIVE BAND THAT HAS UPSTREAM CONNECTION TO LAKE SUPERIOR. THIS PRECONDITIONING SHOULD HELP OVERCOME SLIGHTLY DRIER AIR WORKING ACROSS WISCONSIN EARLY THIS MORNING. NAM-WRF 925MB PLUME ANALYSIS HAS HAD A GOOD HANDLE ON THE SITUATION AND ALONG WITH FSL RUC13 HAVE BEEN USED FOR MOST OF THIS FORECAST PACKAGE. OVERALL...CURRENT FORECAST IS IN GOOD SHAPE. QUESTIONS REMAIN WITH HOW FAR EAST THE MEANDERING BAND WILL MOVE AND HOW MUCH SNOW FAR NORTHEAST LAPORTE COUNTY WILL RECEIVE. NAM-WRF 925MB OMEGA FIELDS SUGGEST THIS BAND WILL BECOME NEARLY STATIONARY FROM BRIDGMAN TO SOUTH BEND AND INTO NORTHERN MARSHALL COUNTY. FROM THERE...SOUTHERN END LOOKS TO MOVE ABOUT ACROSS KOSCIUSKO AND SOUTHERN MARSHALL COUNTIES. SO FAR...THIS HAS BEEN PLAYING OUT WELL WITH 08Z RADAR RETURNS SHOWING HEAVIEST SNOW ALONG THE BRIDGMAN TO SBN LINE. HAVE BEEN DECENT RETURNS ACROSS NORTHEAST LAPORTE COUNTY WITH REPORTS OF 2 INCHES AROUND 07Z IN ROLLING PRAIRIE. SO FAR...THE MODELS WESTWARD BIAS APPEARS TO BE RATHER SMALL...MAYBE ONLY 5 TO 10 MILES. BANDS ARE FINALLY MAKING THEIR WAY INTO SOUTHWEST CASS AND EXTREME NORTHWEST ELKHART COUNTY. AT THIS TIME...IT DOES LOOK LIKE THE MAIN BAND WILL BE SLIGHTLY EAST OF STRONGEST OMEGA DEPICTION ON NAM-WRF...JUST GETTING IT INTO WESTERN PORTIONS OF THESE COUNTIES. RADAR RETURNS FROM KLOT AND TMDW SUGGEST A SECOND NARROW BAND WILL PERSIST JUST TO THE WEST OF MAIN BAND. THIS WILL AFFECT MAINLY FAR SOUTHERN BERRIEN AND NORTHERN LAPORTE COUNTIES. CONCERNED THAT FAR NORTH AND NORTHEAST LAPORTE COUNTY WILL EXCEED 6 INCHES THIS MORNING. CONTEMPLATING ADDING TO THE WARNING. REMAINDER OF WARNING AND ADVISORY AREA EXPECTED TO STAY THE SAME. WILL BREAK OUT CASS AND ELKHART COUNTIES TO ENHANCE WORDING FOR WESTERN PORTIONS. MOISTURE BEGINS TO WANE DURING THE DAY AS 1040MB HIGH IN THE PLAINS NUDGES EAST. LIKE THE NAM-WRF DEPICTION OF LAKE AGGREGATE TROUGH REMAINING OVER LAKE MICHIGAN THIS EVENING AND WEST TO SOUTHWEST FLOW COUPLED WITH DELTA T VALUES IN THE UPPER TEENS TO KEEP STRATUS AND SOME LIGHT SNOW SHOWERS OR FLURRIES AROUND. DID TRIM POPS BACK AWAY FROM THE LAKE BASED ON 925MB FORECAST OF TRAJECTORIES AND RH FIELDS. CONTINUED TO CUT MOS TEMPS AWAY FROM LAKE WHERE SKIES WILL CLEAR TONIGHT. SHOULD SEE AREAS DIP WELL INTO TEENS AND POSSIBLY SOME SINGLE DIGITS IF SKIES CLEAR EARLY IN THE SOUTHWEST. && .LONG TERM... WEDNESDAY THROUGH MONDAY...OVERALL...ONGOING GRIDS/ZFP APPEAR ON TRACK...SO DID NOT MAKE ANY SIGNIFICANT CHANGES THIS PERIOD. AS HAS BEEN THE CASE FOR MOST OF THIS WINTER SO FAR...THE LONGWAVE TROF WILL NOT BE ABLE TO BECOME ESTABLISHED OVER THE MIDWEST IN THE CURRENT HIGHLY PROGRESSIVE PATTERN. IN THE BEGINNING OF THIS PERIOD...WARM AIR ADVECTION INCREASES RAPIDLY WEDNESDAY AS THE SURFACE HIGH MOVES EAST OF THE AREA. TEMPERATURES SHOULD RECOVER TO NEAR NORMAL WEDNESDAY AND THURSDAY. UNLIKE THE LAST SYSTEM...NOT MUCH MOISTURE WILL BE ABLE TO ADVECT INTO THE AREA...SO JUST KEPT LAKE EFFECT SNOW SHOWERS FRIDAY THROUGH SATURDAY IN THE COLDER AIR. THE GFS HAS ALREADY BEGUN TO RETREAT WITH THE VERY COLD AIR SATURDAY...WHICH IS REFLECTED IN THE MEX MOS HIGHS AT OR ABOVE FREEZING AT FWA FROM FRIDAY THROUGH MONDAY. THE ECMWF IS VERY PROGRESSIVE WITH THE SHORT WAVE INDICATING NOT MUCH OF A CHANCE FOR TEMPERATURES TO STAY BELOW NORMAL OVER THE WEEKEND. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR INZ004-INZ005. LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR INZ012-INZ014-INZ016. LAKE EFFECT SNOW WARNING UNTIL 3 PM CST THIS AFTERNOON FOR INZ003. MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...LASHLEY LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 330 PM EST TUE JAN 16 2007 .SYNOPSIS... 18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A DEEP TROUGH EXTENDING FROM MUCH OF EASTERN CANADA DOWN THROUGH THE GREAT LAKES TO THE CENTRAL PLAINS. FURTHER UPSTREAM WE SEE LONGWAVE RIDGING OVER MUCH OF THE WEST. THIS RIDGING IS BEGINNING TO BREAK DOWN AS POTENT SHORTWAVE ENERGY APPROACHES THE PACIFIC NORTHWEST. AT THE SURFACE WE SEE A COLD FRONT STRETCHING FROM JUST OFF THE NORTHEAST COAST DOWN THE I-95 CORRIDOR TO THE NORTHERN FLORIDA PENINSULA. THIS FRONT WILL USHER IN A TRUE FEEL OF WINTER TO MUCH OF THE EASTERN PORTION OF THE COUNTY. ACROSS OUR AREA THIS FRONT MOVED THROUGH DURING THE MORNING AND EARLY AFTERNOON HOURS. TEMPERATURES STARTING OUT IN THE UPPER 50S AND 60S HAVE FALLEN OFF DURING THE PAST SEVERAL HOURS BACK INTO THE LOWER AND MIDDLE 50S MANY LOCATIONS AND EVEN SOME UPPER 40S ACROSS SOUTHEASTERN ALABAMA. TEMPERATURES STILL HOLDING UP ACROSS THE FAR SOUTHEAST BIG BEND BUT EVEN HERE TEMPERATURES WILL TAKE A TUMBLE DURING THE EVENING. PLENTY OF CLOUDCOVER SEEN BEHIND THE FRONT WITH SCATTERED SHOWERS/AREAS OF LIGHT RAIN. THIS PRECIP CONTINUES ON THE LIGHT SIDE AND IS HAVING ITS BIGGEST IMPACT ON FURTHER COOLING OF THE LOW LEVEL TEMPERATURES. && .SHORT TERM... (TONIGHT-FRIDAY) COLD FRONT CONTINUES TO SETTLE TO THE SOUTH AND EAST OF THE FORECAST AREA THIS EVENING WITH COOL AIR ADVECTING INTO ALL OF THE REGION ON NORTHERLY WINDS. CONTINUING TO SEE AREAS OF LIGHT RAIN ALONG AND BEHIND THE FRONT AND THESE AREAS WILL BE AROUND THROUGH THE EVENING HOURS. RECENTLY HAVE SEEN A BIT MORE CONCENTRATED AREA OF LIGHT RAIN DEVELOP TO THE WEST OF OUR AREA AND WILL NEED TO WATCH THIS AREA JUST IN CASE POPS NEED TO BE BUMPED UP ACROSS THE WESTERN ZONES. GUIDANCE IS IN GOOD AGREEMENT ON DECREASING RAIN COVERAGE BY LATE THIS EVENING AND WOULD EXPECT THIS AREA TO SHRINK WITH TIME. DYNAMICS FOR THE PRECIP REMAIN VERY WEAK. STILL APPEARS THAT WE ARE SEEING JUST ENOUGH LARGE SCALE LIFT FROM WEAK DEEP LAYER Q-VECTOR CONVERGENCE AND ASSOCIATED UPPER LEVEL DIVERGENCE IN RIGHT ENTRANCE REGION OF 300MB 150+ KNOT JET CUTTING THROUGH THE TENNESSEE/SOUTHERN OHIO VALLEYS. MAIN AREAS OF PRECIP SHOULD DIMINISH WITH TIME AS THESE FEATURES LIFT OUT TO THE NORTHEAST LATER THIS EVENING AND OVERNIGHT. THE NEXT COUPLE OF DAYS WILL BE ON THE COOL SIDE COMPARED TO THE GENERAL RECENT WARMTH. ALTHOUGH DAYTIME HIGHS WILL BE ON THE COOL SIDE WEDNESDAY AND THURSDAY...DIURNAL RANGES WILL BE KEPT SMALL WITH ABUNDANT CLOUDCOVER...SHOWER CHANCES AND LOW LEVEL WINDS. NIGHTTIME LOWS WILL GENERALLY BE IN THE UPPER 30S TO LOWER 40S NORTH AND IN THE LOWER TO MIDDLE 40S SOUTH. MODELS ARE SHOWING AN INVERTED TROUGH TAKING SHAPE OFF THE EAST COAST OF FLORIDA WEDNESDAY NIGHT AND THEN CLOSING OFF DURING THURSDAY MORNING. CONFIDENCE IN THIS FEATURE IS A LITTLE LOWER THAN AVERAGE...ESPECIALLY WITH THE PRECIP FIELDS. GFS IS SHOWING A RATHER CONCENTRATED AREA OF RAIN ACROSS OUR GA ZONES WEDNESDAY NIGHT INTO THURSDAY MORNING. UNDERCUT GFS POPS BY QUITE A BIT WITH THIS FORECAST PACKAGE AS WOULD EXPECT THE NORTHEAST FLOW TO CONTINUE ADVECTING RELATIVELY DRY LOW LEVEL AIR INTO THE REGION AND DECREASE RAIN COVERAGE AND AMOUNTS. WILL GO GENERALLY WITH CHANCE POPS FOR THE EASTERN HALF OF THE AREA WITH HIGH CHANCE POPS ACROSS SOUTH-CENTRAL GA FOR THE TIME BEING. OTHER LOW CONFIDENCE ITEM WITH THIS FEATURE WILL BE THE IMPACT ON TEMPERATURES FOR MAINLY OUR GA ZONES. IF THE DRY AIR ADVECTION MENTIONED ABOVE IS IN PLACE WITH SOME LIGHT PRECIP FIELDS...THEN TEMPERATURES LATE WEDNESDAY NIGHT INTO THURSDAY MAY BE COOLER THAN ADVERTISED IN OUR GRIDS AS WET-BULB EFFECTS TAKE PLACE. AT THE MOMENT WE HAVE HIGHS AROUND 50 FAR NORTH TO LOWER AND MIDDLE 50S SOUTH. COULD SEE THINGS AN ADDITIONAL 5+ DEGREES COOLER IF EVERYTHING COMES TOGETHER JUST RIGHT. ANY SHOWERS ASSOCIATED WITH THE EAST COAST SYSTEM WILL BE PULLING AWAY DURING THURSDAY AFTERNOON WITH SOME BREAKS OF SUN LIKELY ACROSS OUR WESTERN/SOUTHERN ZONES. WEAK HIGH PRESSURE THEN TRIES TO BUILD IN FOR THURSDAY NIGHT AND FRIDAY AS MID/UPPER LEVEL SHORTWAVE ENERGY DIVES INTO THE SOUTHEAST. .LONG TERM... (FRIDAY NIGHT-MONDAY) THE SHORTWAVE TROF MOVING THROUGH ON FRIDAY NIGHT APPEARS TO BE STRONG ENOUGH TO CLEAR THE REGION TO PRODUCE A BREAK IN THE UNSETTLED WX OVER MUCH OF THE WEEKEND...ALTHOUGH THE SFC RIDGE BEHIND THE NEXT COLD FRONT DOES APPEAR TO BE SUBSTANTIALLY WEAKER. THIS IS NOW SUPPORTED BY BOTH THE GFS AND ECMWF...WHICH ALSO SHOW THE NEXT LOW HEADING OUR WAY ON SUNDAY NIGHT AND MONDAY. && .AVIATION... THE COLD FRONT HAS NOW CLEARED ALL THE TAF SITES...SCOURING OUT THE AREAS OF FOG THAT AFFECTED KTLH...KPFN...AND KVLD EARLIER THIS MORNING. THE TERMINALS ARE NOW LEFT WITH IFR-MVFR CEILINGS WITH A OCCASIONAL SPRINKLES OR DRIZZLE. ALL OF THE NUMERICAL GUIDANCE SHOWS THE BOUNDARY LAYER MOISTURE DECREASING FROM NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON AND EARLY EVENING...WITH CEILINGS RISING TO THE VFR CATEGORY. THIS SEEMS REASONABLE BASED ON UPSTREAM OBSERVATIONS. A SOLID DECK OF AC (10-15K FT) IS FORECAST TONIGHT AND WEDNESDAY. THE VISIBILITY WILL BE P6SM DUE TO THE DRIER AIR AND GOOD MIXING FROM NORTHERLY WINDS OF 10 KT. && .MARINE... COLD FRONT WILL EXIT TO THE SOUTH AND EAST OF THE COASTAL WATERS THIS EVENING. NORTHERLY WINDS AND SEAS WILL INCREASE TO ADVISORY CRITERIA FOR ALL LEGS THIS EVENING. WINDS WILL COME AROUND TO THE NORTHEAST ON WEDNESDAY WITH ADVISORY LEVEL WINDS AND SEAS CONTINUING ACROSS THE OFFSHORE LEGS THROUGH MUCH OF THE DAY. SCATTERED LIGHT SHOWERS WILL ALSO BE SEEN ACROSS THE FORECAST WATERS BEHIND THE FRONT. LOW PRESSURE IS EXPECTED TO DEVELOP WEDNESDAY NIGHT AND THURSDAY OFF THE SOUTHEAST COAST BUT SHOULD HAVE LITTLE IMPACT ON THE FORECAST WATERS OTHER THAN BACKING WINDS AROUND TO THE NORTH ONCE AGAIN. HIGH PRESSURE WILL THEN REMAIN CENTERED WELL OFF TO THE WEST FOR THE LATE WEEK PERIOD KEEPING WINDS LIGHT OUT OF THE NORTHEAST. && .FIRE WEATHER... RED FLAG CONDITIONS ARE NOT EXPECTED THROUGH THE NEXT FEW DAYS. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 42 55 43 57 44 / 30 30 40 30 15 PANAMA CITY 42 58 45 60 47 / 30 30 30 20 20 DOTHAN 39 52 40 55 43 / 30 30 30 30 20 ALBANY 40 52 40 52 41 / 30 30 40 40 20 VALDOSTA 43 53 43 53 41 / 30 40 50 40 15 CROSS CITY 47 60 47 64 45 / 30 40 40 20 15 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GMZ750/755...SMALL CRAFT ADVISORY IN EFFECT 700 PM EST (600 PM CST) THIS EVENING THROUGH 700 AM EST (600 AM CST) WEDNESDAY MORNING. GMZ770/775...SMALL CRAFT ADVISORY IN EFFECT 700 PM EST (600 PM CST) THIS EVENING THROUGH 700 PM EST (600 PM CST) WEDNESDAY EVENING. && $$ AVIATION...FOURNIER REST OF DISCUSSION...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1055 AM CST TUE JAN 16 2007 .DISCUSSION... WILL BE MAKING MINOR UPDATES TO THE FORECAST TODAY. SCATTERED LIGHT SNOW SHOWERS AND FLURRIES EAST OF PEORIA AND SPRINGFIELD SHOULD CONTINUE TO DIMINISH EARLY THIS AFTERNOON LEAVING JUST LAKE EFFECT SNOW BANDS OVER SOUTHERN LAKE MI INTO NW INDIANA. STRATCO CLOUDS THAT WERE CLEARING NORTH AND WEST OF LINCOLN...APPEARS TO BE FILLING BACK IN A BIT LIKE AT PEORIA. CURULE SHOWS BROKEN LOW CLOUDS TO LINGER OVER EASTERN AND NE IL MUCH OF THIS AFTERNOON KEEPING IT MOSTLY CLOUDY. WESTERN IL TO ENJOY MOSTLY SUNNY SKIES. BUT IT WILL BE COLD WITH NW FLOW OFF SNOW FIELD OVER IOWA AND NW IL WITH 1 INCH OF SNOW ON GROUND FROM IL RIVER NW...DUSTING OVER REST OF CENTRAL/SE IL. HIGHS TO RANGE FROM 15 TO 20F FROM I-55 WEST TO THE MID 20S OVER SE IL. AFTER 37 CONSECUTIVE DAYS OF ABOVE NORMAL TEMPS AT PEORIA... SPRINGFIELD AND LINCOLN FROM DEC 10 TO JAN 15...TODAY THE ABOVE NORMAL TEMPERATURE STRETCH SHOULD BE BROKEN WITH BELOW NORMAL TEMPS EXPECTED. SURFACE MAP AT 16Z SHOWS STRONG 1042 MB ARCTIC HIGH PRESSURE OVER THE CENTRAL PLAINS OVER EASTERN KS/NE NEAR THE WESTERN IA/MO BORDERS. ALOFT AN UPPER LEVEL TROF WAS OVER THE GREAT LAKES INTO IL WITH A WEAK SHORT WAVE GENERATING THE LIGHT SHOW SHOWERS/FLURRIES OVER PARTS OF CENTRAL IL THIS MORNING. THIS UPPER LEVEL TROF AXIS SHIFTS SE OF CENTRAL IL LATER TODAY TAKING THE LIGHT SHOW SHOWERS AND FLURRIES WILL IT. LOW CLOUDS WILL ALSO DECREASE OVER CENTRAL IL AND OVER EASTERN IL LATE TODAY/EARLY EVENING AS ARCTIC HIGH PRESURE MOVES EAST INTO IA/MO ALLOWING NW WIND 10 TO 15 MPH TO DIMINISH LIGHT BY EVENING. ARCTIC HIGH PRESSURE MOVING OVER IL LATE TONIGHT WILL BRING THE COLDEST NIGHT SINCE DEC 8 WITH LOWS IN THE SINGLE DIGITS OVER PARTS OF CENTRAL IL. WOULD BE EVEN COLDER IF WE HAD A DEEPER SNOW COVER. && .PREV DISCUSSION... MAIN CONCERNS IN THE SHORT TERM WILL BE CLOUD COVER THROUGH TODAY... AND TEMPERATURES TONIGHT AS SOME OF THE COLDEST AIR SINCE EARLY DECEMBER MOVES INTO THE REGION. SHORT TERM...TODAY THROUGH FRIDAY... WEAK PVA AHEAD OF UPPER LEVEL TROUGH OVER IOWA HAS PROVIDED JUST ENOUGH WEAK LIFT IN A RATHER SHALLOW MOIST LAYER TO KEEP FLURRIES GOING OVERNIGHT ACROSS MUCH OF THE AREA. FLURRIES OR LIGHT SNOW SHOWERS WILL CONTINUE TO BE A THREAT THIS MORNING UNTIL H5 TROUGH AXIS CLEARS THE AREA. OBSERVATIONS SHOW VISIBILITIES ARE GENERALLY 7-10 MILES OR GREATER ACROSS THE AREA... SO ANY ACCUMULATION WILL BE VERY LIGHT FROM HERE ON OUT. THE VERY FINE AND DRY SNOW HAS BLOWN ABOUT QUITE A BIT OVERNIGHT... AND ROAD TRAFFIC HAS INDUCED MELTING/REFREEZING IN SOME LOCATIONS... SO DRIVERS SHOULD BE AWARE OF SLICK SPOTS. CLEARING LINE OF THE LOW CLOUDS IS ROUGHLY CO-LOCATED WITH THE MID LEVEL TROUGH AXIS... AND IT HAS BEEN VERY SLOW MOVING... STALLED OUT JUST WEST OF THE CWA ALL NIGHT. NAM/RUC CROSS SECTIONS AND LAYER RH/WIND PLOTS SUGGEST KEEPING THE LOW CLOUDS ACROSS MUCH OF THE CWA THROUGH NOON TIME... WITH GRADUAL CLEARING WEST OF I-55 EARLY IN THE AFTERNOON... WITH CLOUDS LINGERING UNTIL EARLY EVENING IN FAR EASTERN ILLINOIS. SO WHILE IT IS TEMPTING TO GO WITH A MORE OPTIMISTIC SKY FORECAST WITH THE CLEARING LINE SO CLOSE... WILL KEEP THINGS PESSIMISTIC. SATELLITE OBS OVER MISSOURI ACTUALLY SUGGEST THE CLOUDS ARE REDEVELOPING IN BANDS PARALLEL WITH THE LOW LEVEL FLOW... THESE BANDS EVEN SHOW UP WELL IN 88D DATA FROM KLSX. CLEARING WILL COME IN OVERNIGHT... BRINGING SOME OF THE COLDEST WEATHER WE HAVE SEEN SINCE EARLY DECEMBER... AND CLEARLY THE COLDEST OF THE YEAR SO FAR. RECENT TRACES AND MINOR ACCUMULATIONS OF DRY SNOW ARE NOT EXPECTED TO HAVE MUCH IMPACT ON LOW TEMPS TONIGHT. WINDS WILL BE LIGHTEST WEST OF I-55 WHERE THE SFC RIDGE AXIS WILL SET UP. UPSTREAM TEMPERATURES THIS MORNING OVER EASTERN IOWA HAVE BEEN MORE INFLUENCED BY THE LIGHT SNOW PACK IN THOSE REGIONS... AND THUS DO NOT EXPECT OUR TEMPERATURES TONIGHT TO BE QUITE SO LOW. EXPECT A SLOW WARMING TREND WED-THU AS HIGH PRESSURE SETTLES OFF TO OUR EAST. HAVE DECREASED MAX TEMPS ON WEDNESDAY AS HIGH PRESSURE REMAINS MORE OR LESS OVERHEAD THROUGH THE AFTERNOON... WITH SFC WINDS NOT REALLY SHIFTING UNTIL EVENING. ANY WAA JUST ALOFT WILL LIKELY HAVE A HARD TIME MIXING DOWN TO THE SFC WITH STRONG SUBSIDENCE INVERSION IN PLACE. A WEAK CLIPPER SYSTEM WILL APPROACH FRIDAY INTO FRIDAY NIGHT... AND WHILE SOME SCATTERED FLURRIES CANNOT BE COMPLETELY RULED OUT... CHANCES ARE STILL TOO LOW TO MENTION IN THE FORECAST THIS FAR OUT. THE GFS IS NOW IN AGREEMENT WITH THE ECMWF IN DEFLECTING THE SECOND ARCTIC INTRUSION BEHIND THE CLIPPER WELL TO OUR EAST... BUT TEMPS WILL DIP AGAIN BY THE WEEKEND... WITH SOME REMAINING CLOUD COVER AND A COOL NORTHWEST WIND. HOWEVER... TEMPERATURES WILL BE ONLY A LITTLE BELOW NORMAL IN THIS TIME FRAME. LONG TERM...SATURDAY THROUGH MONDAY... LONGER RANGE SOLUTIONS SUGGEST WE WILL REMAIN IN THIS COOLER/NEAR NORMAL PATTERN EVEN OUT THROUGH DAY 10... AS H5 LOW REMAINS ANCHORED OFF BAFFIN ISLAND... WITH THE MEAN LONGWAVE TROUGH POSITION ACROSS THE NORTHEASTERN CONUS. THE +72 HR AND +240 HR ECMWF H5 PLOTS... VALID THIS AND NEXT THURSDAY NIGHT... LOOK ALMOST IDENTICAL. NEXT CHANCE FOR PRECIP WILL COME TOWARDS SUN/MON AS A CUTOFF LOW CURRENTLY PINCHING OFF OVER THE DESERT SOUTHWEST... EJECTS EASTWARD. WITH TEMPERATURES NEAR OR JUST BELOW NORMAL... WINTRY PRECIP MAY BE A THREAT... BUT AT THIS POINT NO MAJOR STORMS APPEAR TO BE ON THE HORIZON. WILL NEED TO KEEP AN EYE ON EJECTING CUTOFF LOW TO SEE IF IT CAN MANAGE TO PHASE WITH SOME NORTHERN STREAM ENERGY WHICH MAY BE MORE CONDUCIVE TO SFC CYCLOGENESIS. BEYOND THAT... WE REMAIN IN THE SAME FAMILIAR PATTERN AS THIS WEEK... WITH PERIODIC INTRUSIONS OF COLD AIR MAINLY SCRAPING BY TO OUR EAST. THE GFS IN THE LONGER TERM IS QUITE A BIT COLDER FOR US THAN THE ECMWF AS IT BRINGS DOWN THE ARCTIC AIR ACROSS THE MIDWEST INSTEAD OF THE EAST COAST... BUT THE GFS EARLIER PREDICTED THE SAME THING FOR THIS WEEK... AND ONLY IS JUST NOW CATCHING UP WITH THE ECMWF. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUETTL/HARDIMAN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 PM EST TUE JAN 16 2007 .AVIATION...(18Z TAFS) FOCUS REMAINS ON LAKE EFFECT SNOW BAND. BAND AXIS HAS SHIFTED WEST OF KSBN THOUGH SOME DEBRIS CLOUD FROM THIS WILL CONTINUE TO IMPACT KSBN THRU AFTN. AS WINDS BECOME MORE NW AND WEST DURING FCST PERIOD EXPECT BAND TO PUSH BACK EAST BUT WITH FETCH SHORTENING IN THIS SCENARIO AND FLOW BECOMING MORE ANTICYCLONIC...DOUBT ANY SNOW WOULD OCCUR WITH THIS. SO WL CONT WITH MULTI LEVELS OF CLOUDS AS CURRENTLY OBSVD THRU 09Z AND SCATTER THIS AS FLOW GOES SW. AT KFWA...DRIER AIR HAS WORKED IN THERE FROM MICHIGAN. SLIGHTLY CYCLONIC CURVATURE AIDING IN FEW TO SCT CU DEVELOPMENT IN VCNTY BUT THIS WILL DISSIPATE BY DARK. LAKE EFFECT BAND MAY DRIFT BACK TO KFWA DURING EVENING HOURS AS FLOW BECOMES MORE WEST THEN SW. AT THIS TIME HAVE ONLY CARRIED THIS AS REMNANTS OF HIGHER PORTIONS OF THESE BANDS WITH SCT080 EXPECTED. && .SHORT TERM...(FROM EARLY MORNING ISSUANCE) TODAY AND TONIGHT... ...SIGNIFICANT LAKE EFFECT SNOW ONGOING... AS EXPECTED...TYPE I LAKE EFFECT SNOW BAND HAS SET UP DOWN THE LONG AXIS OF LAKE MICHIGAN. AT 08Z...GOES 3.9-11 MICRON SHOWS IMPRESSIVE BAND THAT HAS UPSTREAM CONNECTION TO LAKE SUPERIOR. THIS PRECONDITIONING SHOULD HELP OVERCOME SLIGHTLY DRIER AIR WORKING ACROSS WISCONSIN EARLY THIS MORNING. NAM-WRF 925MB PLUME ANALYSIS HAS HAD A GOOD HANDLE ON THE SITUATION AND ALONG WITH FSL RUC13 HAVE BEEN USED FOR MOST OF THIS FORECAST PACKAGE. OVERALL...CURRENT FORECAST IS IN GOOD SHAPE. QUESTIONS REMAIN WITH HOW FAR EAST THE MEANDERING BAND WILL MOVE AND HOW MUCH SNOW FAR NORTHEAST LAPORTE COUNTY WILL RECEIVE. NAM-WRF 925MB OMEGA FIELDS SUGGEST THIS BAND WILL BECOME NEARLY STATIONARY FROM BRIDGMAN TO SOUTH BEND AND INTO NORTHERN MARSHALL COUNTY. FROM THERE...SOUTHERN END LOOKS TO MOVE ABOUT ACROSS KOSCIUSKO AND SOUTHERN MARSHALL COUNTIES. SO FAR...THIS HAS BEEN PLAYING OUT WELL WITH 08Z RADAR RETURNS SHOWING HEAVIEST SNOW ALONG THE BRIDGMAN TO SBN LINE. HAVE BEEN DECENT RETURNS ACROSS NORTHEAST LAPORTE COUNTY WITH REPORTS OF 2 INCHES AROUND 07Z IN ROLLING PRAIRIE. SO FAR...THE MODELS WESTWARD BIAS APPEARS TO BE RATHER SMALL...MAYBE ONLY 5 TO 10 MILES. BANDS ARE FINALLY MAKING THEIR WAY INTO SOUTHWEST CASS AND EXTREME NORTHWEST ELKHART COUNTY. AT THIS TIME...IT DOES LOOK LIKE THE MAIN BAND WILL BE SLIGHTLY EAST OF STRONGEST OMEGA DEPICTION ON NAM-WRF...JUST GETTING IT INTO WESTERN PORTIONS OF THESE COUNTIES. RADAR RETURNS FROM KLOT AND TMDW SUGGEST A SECOND NARROW BAND WILL PERSIST JUST TO THE WEST OF MAIN BAND. THIS WILL AFFECT MAINLY FAR SOUTHERN BERRIEN AND NORTHERN LAPORTE COUNTIES. CONCERNED THAT FAR NORTH AND NORTHEAST LAPORTE COUNTY WILL EXCEED 6 INCHES THIS MORNING. CONTEMPLATING ADDING TO THE WARNING. REMAINDER OF WARNING AND ADVISORY AREA EXPECTED TO STAY THE SAME. WILL BREAK OUT CASS AND ELKHART COUNTIES TO ENHANCE WORDING FOR WESTERN PORTIONS. MOISTURE BEGINS TO WANE DURING THE DAY AS 1040MB HIGH IN THE PLAINS NUDGES EAST. LIKE THE NAM-WRF DEPICTION OF LAKE AGGREGATE TROUGH REMAINING OVER LAKE MICHIGAN THIS EVENING AND WEST TO SOUTHWEST FLOW COUPLED WITH DELTA T VALUES IN THE UPPER TEENS TO KEEP STRATUS AND SOME LIGHT SNOW SHOWERS OR FLURRIES AROUND. DID TRIM POPS BACK AWAY FROM THE LAKE BASED ON 925MB FORECAST OF TRAJECTORIES AND RH FIELDS. CONTINUED TO CUT MOS TEMPS AWAY FROM LAKE WHERE SKIES WILL CLEAR TONIGHT. SHOULD SEE AREAS DIP WELL INTO TEENS AND POSSIBLY SOME SINGLE DIGITS IF SKIES CLEAR EARLY IN THE SOUTHWEST. && .LONG TERM... WEDNESDAY THROUGH MONDAY...OVERALL...ONGOING GRIDS/ZFP APPEAR ON TRACK...SO DID NOT MAKE ANY SIGNIFICANT CHANGES THIS PERIOD. AS HAS BEEN THE CASE FOR MOST OF THIS WINTER SO FAR...THE LONGWAVE TROF WILL NOT BE ABLE TO BECOME ESTABLISHED OVER THE MIDWEST IN THE CURRENT HIGHLY PROGRESSIVE PATTERN. IN THE BEGINNING OF THIS PERIOD...WARM AIR ADVECTION INCREASES RAPIDLY WEDNESDAY AS THE SURFACE HIGH MOVES EAST OF THE AREA. TEMPERATURES SHOULD RECOVER TO NEAR NORMAL WEDNESDAY AND THURSDAY. UNLIKE THE LAST SYSTEM...NOT MUCH MOISTURE WILL BE ABLE TO ADVECT INTO THE AREA...SO JUST KEPT LAKE EFFECT SNOW SHOWERS FRIDAY THROUGH SATURDAY IN THE COLDER AIR. THE GFS HAS ALREADY BEGUN TO RETREAT WITH THE VERY COLD AIR SATURDAY...WHICH IS REFLECTED IN THE MEX MOS HIGHS AT OR ABOVE FREEZING AT FWA FROM FRIDAY THROUGH MONDAY. THE ECMWF IS VERY PROGRESSIVE WITH THE SHORT WAVE INDICATING NOT MUCH OF A CHANCE FOR TEMPERATURES TO STAY BELOW NORMAL OVER THE WEEKEND. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR INZ004-INZ005. LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR INZ012-INZ014-INZ016. LAKE EFFECT SNOW WARNING UNTIL 3 PM CST THIS AFTERNOON FOR INZ003. MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MIZ077-MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...LASHLEY LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 219 PM MST TUE JAN 16 2007 .DISCUSSION...FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING THAT FLOW HAS BECOME MORE AMPLIFIED OVER THE LAST 24 HOURS... ESPECIALLY FROM THE CENTRAL PACIFIC INTO WESTERN NORTH AMERICA. LARGE AND COLD UPPER SYSTEM NEAR THE DATELINE HAS PUMPED UP THE RIDGE BEHIND SYSTEM NOW DIGGING INTO THE WEST COAST. NORTHERN PORTION OF THIS TROUGH OVER WESTERN CANADA IS MOVING SOUTHEAST. WEAK UPPER OVER SOUTHERN ARIZONA IS ABOUT TO START MOVING NORTHEAST. AT JET LEVEL...MODELS LOOKED LIKE THEY INITIALIZED REASONABLY WELL. HOWEVER...THEY MAY BE A LITTLE LOW ON SPEEDS ON THE JET SEGMENT BEHIND SYSTEM DIGGING ONTO THE COAST. AT MID LEVELS...MODELS INITALIZED OKAY. HOWEVER...THEY MAY NOT BE STRONG WITH THE NORTHERN PORTION OF THE TROUGH MOVING INTO THE PACIFIC NORTHWEST. ALSO MODELS ARE UNDERDOING STRENGTH OF WESTERN RIDGE. NAM/WRF IS DOING THE BEST. AT LOW LEVELS...NAM WAS DOING THE BEST OF THE BUNCH WITH SURFACE WINDS/PRESSURES. IT HAD THE EXITING RIDGE THE STRONGEST AND FURTHWEST WEST WITH THE HIGHER PRESSURES. ALSO NAM WAS DOING BETTER WITH THE DEVELOPING LEE TROUGH. THE RUC13 LOOKED CLOSE TO THE NAM. SAME PROBLEM YESTERDAY WITH LOW LEVEL TEMPERATURES BUT NOT AS BAD. MODELS DO NOT HAVE COLD POOL FAR ENOUGH SOUTH AND WEST. THE UKMET WAS DOING SLIGHTLY BETTER THAN THE GFS. WILL BE DOING A BLEND OF THE MODELS. BELIEVE THE NAM/UKMET MAY BE DOING BETTER INITIALLY AT MID AND UPPER LEVELS. THEY HAVE THE NORTHERN STREAM FASTEST AND PRETTY STRONG. WILL THEN BE TRENDING TOWARD THE ECMWF IN THE MIDDLE OF THE PERIOD. TONIGHT/WEDNESDAY...SYSTEM OVER THE DESERT TO MOVE ACROSS DURING THIS PERIOD. IT WILL BE WEAK AND HAVE LITTLE MOISTURE WITH IT. HAVE WARMED UP INTO THE MIDDLE 20S MOST LOCATIONS. WILL STICK CLOSE TO NUMERICAL GUIDANCE FOR TONIGHT. BELIEVE WINDS WILL STAY UP ENOUGH TO KEEP TEMPERATURES FROM PLUMMETING. MAV DID DO TOO BAD TONIGHT. TEMPERATURE FALL WILL BE IN THE EVENING BEFORE WARM AIR ADVECTION KICKS. SOME CLOUDS AROUND TOMORROW BUT WILL NOT BE THICK. AGAIN WARM ADVECTION WILL BE OVER SNOW PACK WILL TREND TO NEAR OR SLIGHTLY COOLER THAN GUIDANCE. NAM 2 METER FROM YESTERDAY WAS A SLIGHTLY COLD FOR TODAY BUT CLOSEST. WEDNESDAY NIGHT/THURSDAY...SYSTEM THAT WILL HAVE A LITTLE MORE IMPACT ON OUR WEATHER WILL BE SYSTEM OVER WESTERN CANADA. AS THIS SYSTEM DIVES SOUTHEAST...IT WILL PUSH A REINFORCING OF COLD AIR INTO THE AREA. FRONTAL PASSAGE LOOKS TO BE LATE IN THE NIGHT OR EARLY IN THE DAY PERIOD. BECAUSE OF THE COLD ADVECTION OVER SNOWPACK AND SOME CLOUDS...WILL GO CLOSER TO THE COOLER GUIDANCE. THURSDAY NIGHT/FRIDAY...SURFACE RIDGE WILL BE OVER THE AREA OR JUST PULLING AWAY DURING THIS PERIOD. WILL BE UNDER WEAK RIDGE OR NORTHWEST FLOW ALOFT. BECAUSE ALL THIS...WILL NOT BE TOO AGGRESSIVE IN WARMING THINGS...AND WILL GO WITH PREVIOUS TRENDS. SATURDAY THROUGH TUESDAY...STILL SOME VARIABILITY IN MODEL SOLUTIONS BUT THEY ARE GETTING CLOSER. DIFFERENCES EXIST ON WHERE THEY CUT OFF NEW LOW...AND WHERE/HOW FAST AND HOW STRONG THEY KICK THIS SYSTEM. UKMET AND CANADIAN LOOK TO CUT IT OFF FURTHER SOUTHWEST. CANADIAN IS FURTHER SOUTHWEST AND SLOWER THAN ANY OF THE MODELS THROUGH TIME. EVENTUALLY THE ECMWF KICKS OUT THE SYSTEM FASTER... FURTHER NORTH...AND WEAKER. IT HAS BEEN THE MOST CONSISTENT THE LAST COUPLE OF DAYS. THE NEWEST GFS IS MORE CUT OFF...SLOWER...AND FURTHER SOUTH THAN THE PREVIOUS COUPLE OF RUNS. LIKE HPCS ASSESSMENT OF THE SITUATION...AND AGREE THAT THE ECMWF IS THE WAY TO GO AT THIS TIME. BELIEVE SYSTEM COULD DIVE PRETTY FAR SOUTH BASED ON THE STRONG RIDGING BEHIND IT. ALSO LIKE THE FASTER KICKING OUT SYSTEM BASED ON JET POSITION AND FORECAST. SO ENDED UP ADDING A SLIGHT CHANCE OF LIGHT SNOW ON SATURDAY NIGHT. THINGS MAY GET STARTED LATE IN THE AFTERNOON BUT FEEL IT WILL BE SPRINKLES AT THIS TIME. IF ECMWF TIMING IS RIGHT... PRECIPITATION WILL BE DONE BY 12Z SUNDAY. HOWEVER...IF GFS TIMING IS RIGHT...PRECIPITATION MAY NEED TO BE PULLED INTO SUNDAY. LEFT HIGH SILENT POPS IN FOR SUNDAY. SO SATURDAY WILL BE COOL WITH CLOUDS. COLD AIR GETS PULLED IN BEHIND SYSTEM ON SUNDAY...AND LIKE THE COOLER GUIDANCE BOTH DAYS. SUNDAY LOOKS TO BE DRY. NORTHERN STREAM SYSTEM DIGS INTO WESTERN AND NORTHERN PORTIONS OF THE COUNTRY ON MONDAY AND TUESDAY. BETTER LIFT LOOKS TO BE OFF TO THE WEST SO KEPT THE FORECAST DRY. HOWEVER...COLD AIR DEFINITELY GETS PULLED BACK...AND THE COLDER HPC TEMPERATURES LOOK GOOD. OTHER THAN KEEPING MONDAY DRY...MADE LITTLE IF ANY CHANGES TO HPC GUIDANCE. THANKS TO THE SURROUNDING OFFICES FOR THE COLLABORATION. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER/BLAIR ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 435 PM EST TUE JAN 16 2007 .DISCUSSION... MAIN FCST ISSUE TONIGHT IS HOW COLD WILL IT GET...THEN ATTENTION TURNS TO UPCOMING SNOW CHANCES OF WHICH THERE ARE SEVERAL OVER THE NEXT 7 DAYS. COULD BE A COUPLE OF DECENT LES/LAKE ENHANCED EVENTS IN THE MIX AS WELL WHICH IS GOOD NEWS FOR THOSE LOOKING FOR WINTER RECREATION. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW POSITIVE TILT TROF EXTENDING FROM SE CANADA TO THE SRN ROCKIES WHILE A RIDGE WAS OVER THE NRN U.S. ROCKIES INTO SASKATCHEWAN/MANITOBA. UPSTREAM RIDGE WAS SUPPORTING SFC HIGH PRES FROM THE CNTRL PLAINS TO WRN LAKE SUPERIOR/ONTARIO. ARRIVAL OF SFC RIDGE AND INCREASINGLY DRY AIRMASS/LOWERING INVERSION (NOTE 12Z KINL SOUNDING) HAS LED TO DIMINSHING LES TODAY OFF LAKE SUPERIOR. TO THE W...DEVELOPING WAA PATTERN IS LEADING TO MID CLOUD DECK OVER NW MN/NE ND INTO MANITOBA. LOOKS LIKE THERE WILL BE A SHORT WINDOW THIS EVENING FOR TEMPS TO QUICKLY PLUMMET OVER FRESH SNOW PACK. LINGERING LAKE EFFECT CLOUDS ARE ALREADY SHOWING SIGNS OF DEPARTING THE INTERIOR SW FCST AREA AND UPSTREAM MID CLOUDS ARE STILL MANY HRS AWAY (SIMPLE EXTRAPOLATION PUTS CLOUDS INTO KIWD VCNTY AROUND 04Z). WITH WINDS TO DECOUPLE FOR A TIME WITH SFC RIDGE OVER THE AREA...TEMPS SHOULD NOSE DIVE WITH MANY AREAS SEEING SUBZERO READINGS OVER THE INTERIOR W AND CNTRL. SHOULD FINALLY SEE FIRST SUBZERO READING OF THE WINTER HERE AT THE OFFICE TONIGHT. AT THE LOW END...HAVE GONE CLOSE TO GFS COOP MOS WHICH TAKES TEMPS DOWN TO -8C AT CHAMPION. THAT SHOULD BE A COMMON READING FOR THE TYPICAL INTERIOR COLD SPOTS IN THE INTERIOR W HALF OF FCST AREA. COUNTING ON RETURN FLOW ON BACKSIDE OF SFC RIDGE AND INCREASING CLOUDS LATE EVENING/OVERNIGHT TO KEEP TEMPS FROM FALLING MORE...BUT WILL NEED TO KEEP AN EYE ON TRENDS THIS EVENING. AS FOR LES...WILL CANCEL ADVY FOR ALGER/LUCE/NRN SCHOOLCRAFT WITH FCST ISSUANCE. ADDITIONAL ACCUMULATIONS WILL BE 1 INCH OR LESS BEFORE WINDS BACK OFFSHORE...ENDING LINGERING LES AROUND MIDNIGHT. FAIRLY STRONG ISENTROPIC ASCENT/WAA PATTERN WILL DEVELOP OVER THE AREA LATE TONIGHT/WED MORNING...BRINGING INCREASING CLOUDS. IT APPEARS BEST POTENTIAL OF MOISTENING THE LOW LEVELS TO ALLOW SNOW TO REACH THE SFC WILL OCCUR JUST N OF UPPER MI. HAVE THUS PAINTED SNOW CHANCES ONLY ACROSS THE N HALF OF LAKE SUPERIOR LATE TONIGHT/WED. GIVEN STRENGTH OF ASCENT...WOULDN`T BE SURPRISED IF A FEW FLURRIES BRUSH THE KEWEENAW OR ALGER/LUCE COUNTIES. COOLER GFS MOS GUIDANCE LOOKED REASONABLE FOR HIGHS WED SINCE THERE SHOULD BE SOME DELAY WARMING THE NEAR SFC LAYER AFTER RECENT CHILL. THU/FRI...ATTENTION TURNS TO TROF WHICH AMPLIFIES OVER THE PLAINS AND THEN MOVES ACROSS THE GREAT LAKES. SEVERAL SHORTWAVES WILL BE EMBEDDED WITHIN THE TROF WITH FIRST LIFTING NE INTO THE UPPER LAKES THU AFTN. AIRMASS IS INITIALLY DRY...SO NOT EXPECTING MUCH IN THE WAY OF -SN COVERAGE WITH IT. HAVE THUS DELAYED CHC POPS FROM INHERITED FCST...LEAVING THE E DRY THRU THU MORNING. MORE IMPORTANT SYSTEM CROSSES THE AREA THU NIGHT WITH SHARP WIND SHIFT AND STRONG CAA IN ITS WAKE. LOOKS LIKE A GOOD SETUP FOR A PERIOD OF LAKE ENHANCEMENT (850MB TEMPS ARE ALREADY LOW ENOUGH FOR JUST PURE LES AT THE TIME OF TROF PASSAGE/SYNOPTIC FORCING). EXAMINATION OF GFS FCST SOUNDINGS SUPPORTS POTENTIAL FOR A PERIOD OF MDT/HVY SNOW WITH DEEP MOISTURE THRU AT LEAST 15KFT AND UPWARD MOTION INTERSECTING DECENT DEPTH OF FAVORABLE DENDRITIC SNOW GROWTH TEMPS. ALTHOUGH SNOWBELTS FAVORED UNDER NW WINDS WILL SEE HEAVIEST SNOW...WINDS SOMETIMES VEER MORE SHARPLY TO THE N IN THESE TYPE OF EVENTS. SO THERE MAY BE A BRIEF PERIOD OF MDT/HVY SNOW FOR N WIND FAVORED LOCATIONS AS WELL THU NIGHT. ANOTHER SHORTWAVE DROPPING SE ACROSS THE AREA FRI AFTN SHOULD GIVE A BOOST TO LES AGAIN. AT THIS POINT...IT APPEARS THIS WILL BE A SOLID ADVY TYPE EVENT FOR LAKE SUPERIOR COUNTIES AND POTENTIALLY A WARNING EVENT FOR A FEW LOCATIONS. SAT THRU TUE...IN THE BIG PICTURE...MEDIUM RANGE GUIDANCE FAVORS ANOTHER TROF BECOMING ESTABLISHED LATE IN THE WEEKEND AND EARLY NEXT WEEK OVER THE GREAT LAKES/MISSISSIPPI VALLEY AS RIDGE AMPLIFIES ALONG THE W COAST. SO THIS SHOULD GENERALLY BE A SNOWY PERIOD... ESPECIALLY NEAR LAKE SUPERIOR. THERE ARE SOME ISSUES ON TIMING AND DETAILS OF THE TROF TAKING SHAPE OVER THE REGION LATE IN THE WEEKEND. 00Z ECMWF DROPS A PAIR OF SHORTWAVES SE WITH THE FIRST LEADING TO A SFC LOW OVER LAKE SUPERIOR/UPPER MI SUN EVENING. THIS IS FOLLOWED BY ANOTHER SHORTWAVE MON WHICH INTRODUCES A SHOT OF ARCTIC AIR. THIS WOULD BE FAVORABLE FOR SIGNIFICANT SNOW FOR THE ENTIRE FCST AREA NEAR LAKE SUPERIOR. 00Z GFS WAS SIMILAR TO THE ECMWF...BUT GENERALLY 12HRS SLOWER. 00Z UKMET WAS ALSO SUPPORTIVE FOR THE PATTERN OVER GREAT LAKES AREA...BUT UPSTREAM RIDGE ALONG THE W COAST IS MUCH FLATTER BY 00Z MON...SUGGESTING LESS AMPLIFIED TROFFING HERE EARLY NEXT WEEK. 00Z CANADIAN GLOBAL WAS ALSO SUPPORTIVE OF THE OVERALL PATTERN...BUT WAS WEAKER WITH FIRST SHORTWAVE. FOR NOW...WILL LEAN TOWARD THE GFS/ECMWF FOR DETAILS (PAIR OF SHORTWAVES DROPPING THRU THE AREA). TIMING WILL REMAIN UNCERTAIN UNTIL EVENT NEARS...AND HAVE THUS UTILIZED HPC GUIDANCE FOR NOW. PATTERN DOES FAVOR A SFC LOW OR SHARP TROF DROPPING ACROSS LAKE SUPERIOR WITH FIRST SHORTWAVE. THIS WOULD PROVIDE A DECENT PERIOD OF LES/LAKE ENHANCED SNOW FOR NW/N WIND FAVORED LOCATIONS. SECOND SHORTWAVE WILL REENERGIZE LES/LAKE ENHANCED SNOW...ESPECIALLY FOR NW WIND FAVORED LOCATIONS. NEAR NORMAL HIGH TEMPS SAT/SUN SHOULD TREND DOWN MON/TUE. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING WEST HALF OF LAKE SUPERIOR. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1124 AM EST TUE JAN 16 2007 .UPDATE... NO BIG CHANGES TO THE GRIDS WERE MADE. JUST MODIFIED SKY/WX TO RELFECT LATEST VIS SATELLITE/RADAR TRENDS. I DID NOT MODIFY THE SNOW AMOUNTS VERY MUCH. USING A SNOW TO LIQUID RATIO OF ABOUT 30/35 TO 1 YIELDS ANOTHER 1 TO 3 INCHES ACROSS THE EAST...WITH JUST A TRACE ACROSS THE FAR WEST. STARTING AROUND 20Z SHOULD START SEEING A GRADUAL DIMINISHING TREND WITH LES ACROSS THE EAST AS INVERSION HEIGHTS DROP AND AS DRIER AIR WORKS IN. WILL MOST LIKELY LET ADVISORIES EXPIRE AT 7PM. && .PREV DISCUSSION... TAKING A LOOK AT THE WATER VAPOR IMAGERY THIS MORNING...MUCH OF THE NATION WAS RELATIVELY DRY. IN GENERAL...ALL BUT THE EASTERN THIRD OF THE NATION WAS UNDER THE INFLUENCE OF HIGH PRESSURE. THERE WERE THREE SURFACE LOWS OF NOTE THIS MORNING. THE FIRST WAS THE EXITING LOW PRESSURE SYSTEM...CENTERED OVER JUST OFF THE NEW ENGLAND COAST...WITH A COLD FRONT STRETCHING THROUGH THE CAROLINAS AND NORTHWESTERN FLORIDA. THE SECOND...SLIGHTLY WEAKER LOW WAS SITUATED OVER THE NORTHWEST TERRITORIES UP IN CANADA. THIS FEATURE HAD A WARM FRONT DROPPING SOUTH THROUGH SASKATCHEWAN AND EASTERN MONTANA. WARMER TEMPERATURES WERE NOTED ACROSS NORTHERN MONTANA. FOR EXAMPLE...THE 09Z TEMPERATURE AT CUT BANK MONTANA WAS 28 DEGREES...WHILE CLOSER TO HOME THE TEMPERATURE WAS -16 AT INTERNATIONAL FALLS. LOOKING HIGHER UP INTO THE ATMOSPHERE...AND THE WATER VAPOR IMAGERY AND RUC...THE MID LEVEL TROUGH WAS SET UP FROM EASTERN LAKE SUPERIOR THROUGH THE SOUTHERN TIP OF THE UPPER PENINSULA...AND DOWN THROUGH IOWA...ALL THE WAY THROUGH SOUTHERN ARIZONA. CONTINUE TO BE CONCERNED WITH LAKE EFFECT SNOW ACROSS OUR THE CENTRAL AND EASTERN LAKE SUPERIOR SHORELINE TODAY. THE BANDS OF SNOW HAVE BEEN CONTINUING THE SLOWLY SHIFT EASTWARD OVERNIGHT AS WINDS HAVE BECOME MORE NORTHWESTERLY...INCREASING THE CONVERGENCE ACROSS THIS AREA. WAS ORIGINALLY CONCERNED WITH THE AMOUNT OF DRY AIR THAT WILL COME INTO THIS AREA WITH OF CENTRAL...WESTERN...AND NORTHERN LAKE SUPERIOR CLOUD FREE EARLIER THIS MORNING. FURTHER TO OUR WEST...DEW POINTS ARE IN THE UPPER TEENS TO MID 20S BELOW ZERO. ACROSS THE CWA DEW POINTS WERE STILL IN THE SINGLE DIGITS ABOVE ZERO. EVEN WITH THIS DRIER AIR FILTERING IN...THE NNW TO SSE CLOUDS HAVE DEVELOPED FAIRLY NICELY OVER THE PAST SEVERAL HOURS ACROSS THE EASTERN HALF OF THE LAKE. THE BETTER FETCH FOR LAKE EFFECT WAS ALSO EXPECTED TO OFFSET SOME OF THIS DRY AIR. EVENING SHIFT DID HOIST ADVISORIES FOR ALGER COUNTY EASTWARD THOUGH THIS EVENING. 3-5KFT INVERSION HEIGHTS...GOOD MOISTURE AROUND THE SNOW GROWTH REGION SHOULD ALLOW FOR ADVISORY CRITERIA THROUGH THIS EVENING. WARM AIR WILL SURGE EASTWARD INTO THE UPPER PENINSULA DURING THE DAY WEDNESDAY AS THE WARM FRONT OVER NORTHEASTERN MONTANA SWINGS OUR WAY AND THE 500MB RIDGE SLIDES OVERHEAD. 850MB TEMPERATURE SHOULD RISING TO THE -1 TO -3 RANGE BY 00Z THURSDAY. WITH THIS SAID...AM HESITANT TO DECREASE CURRENT FORECAST TEMPERATURES ANY...EVEN GIVEN SLIGHTLY COOLER TEMPS FROM THE GFS/MAV WITH MORE CLOUDS ANTICIPATED. SO...FEW CHANGES WERE MADE TO TEMPS FOR MID WEEK. ALSO TO HINDER TOO MANY CHANGES TO THE FORECAST...THE GFS AND NAM ARE BOTH NOT FAVORED FOR MID WEEK AND BEYOND...WITH A QUICKER UKMET/ECMWF SOLUTION PREFERRED. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-007-085. && $$ PEARSON (UPDATE) KF (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 256 PM EST TUE JAN 16 2007 .SHORT TERM /TONIGHT THROUGH THURSDAY/... MAIN FORECAST ISSUE THIS PERIOD IS LAKE EFFECT SNOW TONIGHT WITH SOME MODEL DISAGREEMENT IN REGARD TO THE FLOW FOR THE EVENT. THE NAM DOES NOT SEEM TO HAVE A GOOD HANDLE ON THE SITUATION AND IS HAVING A HARD TIME WITH THE CURRENT BANDS ACROSS CENTRAL NEW YORK, AND TONIGHT THE NAM SOUNDINGS WANT TO TURN THE FLOW MORE WESTERLY TO ABOUT 300 DEGREES. THIS WOULD LIKELY CONSOLIDATE THE MULTI- BANDS INTO MORE OF A STRONGER SINGLE BAND, ESPECIALLY THIS EVENING AFTER PASSAGE OF S/W. THE GFS AND RUC AS WELL AS LAMP DATA STAY MORE WITH 320 FLOW AND MULTI-BAND EVENT. LOOKING UPSTEAM, NO SIGNS OF FLOW BACKING MORE WESTERLY SO WE HAVE DECIDED TO STAY WITH THE MULT-BAND SCENERIO WHICH WILL CONTINUE TO AFFECT MUCH OF CENTRAL NEW YORK COUNTIES THRU THE NIGHT. WITH TEMPERATURES DROPPING INTO THE LOWER TEENS, THE SNOW WILL HAVE A LARGE FLUFF FACTOR AND WILL ACCUMULATE QUICKLY WITH PERSISTENT BANDS. SOME LIGHTER SNOW SHOWERS AND FLURRIES WILL CONTINUE INTO WEDNESDAY MORNING AS HIGH PRESSURE BUILDS EASTWARD FROM THE OHIO VALLEY. AT LEAST SOME FLURRIES MAY CONTINUE THROUGH THE AFTERNOON AS THE FLOW DOES NOT SHIFT TO THE SW LATE IN THE AFTN OR EVENING AS THE SFC HIGH MOVES TO OUR EAST. QUIET DAY ON THURSDAY WITH SFC RIDGE OFF THE NEW ENGLAND COAST AND SWLY FLOW WARMING TEMPS BACK INTO THE 30S. FWC TEMPS ARE QUITE A BIT COLDER THAN THE ETA AND GFS THRU THE PERIOD. TONIGHT THE NGM CLEARS OUT THE FA WHICH IS UNLIKELY ACROSS A LARGE PART OF THE AREA GIVEN LAKE EFFECT. WENT WITH A MET/MAV BLEND FOR MAX AND MINS THRU MOST OF THE PERIOD. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... TROFFING BEGINS TO TAKE HOLD OVER ERN HALF OF NATION THIS WEEKEND. HAVE FOLLOWED HPC GUIDANCE FOR EXTENDED PORTION...BASING FINER DETAILS ON 00Z ECMWF SOLN. SRLY FLOW EXPECTED THUR NIGHT INTO FRIDAY AHEAD OF SYSTEM CROSSING SRN CANADA. NAM AND GFS BRING LOW ALONG ERN SEABOARD ON FRIDAY WITH GFS FURTHER OFFSHORE BASED ON POSITIONING OF SFC LOW IN CANADA. OVERALL...STILL LOOKS COLD ENOUGH FOR SNOW WITH MOST AREA FEELING AFFECTS FROM SYSTEM TO OUR NORTH. WINDS GO WNW FRIDAY AFTERNOON INTO FRIDAY NIGHT...WITH LES CRANKING UP ONCE AGAIN. H8 TEMPS NOT EXPECTED TO BE REAL IMPRESSIVE... DROPPING TO ONLY -10C TO -12C. SFC RIDGE AXIS MAKES A BRIEF APPEARANCE INTO FA ON SATURDAY WITH LITTLE PCPN EXPECTED BTWN 12Z SAT AND 12Z SUNDAY. H5 TROF PASSES THRU AND WK S/WAVE RIDGING COULD BE FELT OVER EARLY HALF OF THE WEEKEND. TEMPS WILL TUMBLE TO NR NORMAL LEVELS (HIGHS IN U20S AND LOWS IN MID-TEENS) AND REMAIN THERE INTO EARLY NEXT WEEK. NEXT SYSTEM PROGGED TO DEVELOP AND HEAD TOWARD THE AREA SUN NIGHT INTO MONDAY WITH YET ANOTHER EAST COAST LOW POSSIBLE. SEVERAL SHOTS OF REINFORCING COLD AIR EXPECTED DURING THIS TIME WITH CHC POPS MOST OF THE PERIOD. && .AVIATION /19Z-18Z/... LAKE EFFECT SNOW WILL CONTINUE THRU MOST OF THE TAF PERIOD AT ALL SITES EXCEPT FOR KELM/KAVP. MOST PERSISTENT BANDS NR KITH AND KBGM WILL PRODUCE MVFR AND OCNL IFR VSBYS THRU 22Z. LES WILL BECOME SLIGHTLY MORE ORGANIZED NR KSYR BTWN 01Z-05Z WITH VSBYS REDUCED TO 1/2SM AT TIMES IN MODERATE SNOW SHOWERS. CIGS EXPECTED TO DROP TO NR 800FT IN HEAVIEST SQUALLS. REMAINDER OF SITES WILL SEE MVFR CIGS OVERNIGHT. EXCEPTION WILL BE AT KAVP WHERE ONLY SCTD CEILINGS FCST THRU THE PERIOD. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR NYZ017-018-025-044-045. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM 300 PM MST TUE JAN 16 2007 .SYNOPSIS... COLD WINTER WEATHER WILL LINGER THOUGH WEDNESDAY WITH TEMPERATURES REMAINING SOME 10 TO 20 DEGREES BELOW SEASONAL VALUES. SNOW FLURRIES ARE POSSIBLE AT TIMES TONIGHT AND INTO WEDNESDAY MORNING MAINLY EAST OF THE RIO GRANDE. THE BORDERLAND WILL HAVE A SLIGHT REPRIEVE IN THE WEATHER WEDNESDAY AFTERNOON INTO THURSDAY MORNING WITH TEMPERATURES WARMING SOMEWHAT. HOWEVER...ANOTHER WINTER STORM IS FORMING OVER THE PACIFIC NORTHWEST AND IS FORECAST TO MOVE INTO ARIZONA THURSDAY...WHICH WILL ADVECT CONSIDERABLE SUBTROPICAL MOISTURE FROM THE GULF OF CALIFORNIA INTO THE BORDERLAND...BRINGING SCATTERED RAIN SOWERS LATER THURSDAY INTO FRIDAY MORNING. FURTHERMORE...ANOTHER VERY COLD POLAR FRONT WILL PUSH SOUTHWARD INTO THE AREA FRIDAY MORNING ADDING TO THE RISK OF A MIXED BAG OF WINTRY PRECIPITATION WHICH COULD INCLUDE FREEZING RAIN AND SLEET BEFORE CHANGING OVER TO SNOW BY FRIDAY EVENING...AND THE SNOW COULD BE POSSIBLY HEAVY AT TIMES OVER BOTH THE MOUNTAINS AND EVEN IN SOME OF THE LOWLANDS. THIS SYSTEM SHOULD MOVE OUT OF THE BORDERLAND BY SATURDAY NIGHT. && .DISCUSSION... NOT AS IF ALL THIS WAS UNEXPECTED BUT SLOWLY AND SURELY THE DETAILS ARE STARTING TO GET INTO SOMEWHAT OF A FOCUS. AS WE WRITE OUR HIGH HAS BEEN 33 DEG F WITH THE RECORD LO MAX TODAY AT 36. SHORT TERM MESO ETA AND RUC SHOW MINOR VORT DISTURBANCES IN THE SUBTROPICAL JET OVERHEAD (FCST TO PEAK AT 160 KTS OHD WEDNESDAY) SO SOME SNOW FLURRIES ARE NOT OUT OF THE QUESTION TONIGHT MAINLY EAST OF THE RIO. THIS SHOULD NOT BE THAT SIGNIFICANT AS ALL WE HAVE IS SATURATED UPSLOPE CLOUDS FROM 850 TO 750 MB AND THEN THE SUBTROPICAL JET CLOUDS 15-20K AGL SO SEEDING SHOULD NOT BE A REAL CONCERN AT THIS TIME. HUDSPETH MAY SEE SOME LIGHT SNOW BUT BETTING UNDER ANY ADVISORY CRITERION AT THIS TIME. OVERALL MODELS IN FAIRLY GOOD AGREEMENT GIVING US A SLIGHT REPRIEVE IN OUR `WINTER` WITH SOME WARMING AND PARTLY CLOUDY CONDITIONS WED AFTN-THU MIDDAY. THEN LIFE GETS INTERESTING WITH BOTH NAM AND GFS DIGGING A STRONG UPPER LOW NOW OVER THE PACIFIC NW (-34C H5) INTO ARIZ BY THURSDAY. THE NAM IS A LITTLE SLOWER BY ABOUT 6-12 HOURS AND LESS AGGRESSIVE ON THE QPF. THE LATEST 12Z GFS ACTUALLY STALLS THE LOW IN SOUTH CENTRAL ARIZ THROUGH SATURDAY MORNING `ALMOST` IN A PERFECT POSITION FOR DYNAMICS (ACTUALLY A TAD NORTH BRINING IT INTO THE NORTHERN PORTION OF OUR CWA SATURDAY BUT CLOSE ENOUGH). THIS SHOULD COUPLE WITH ANOTHER BACKDOOR FRONT INTO INTO THE CWA (1045 MB HIGH DRIVER) BETWEEN 12Z AND 18Z FRIDAY. EXPECT AN EXCELLENT SUBTROPICAL BAJA TAP BY THURSDAY PM WITH RAIN EVEN AT THE HIGH ELEVATIONS. FORECAST SOUNDINGS (BOTH NAM AND GFS) SHOW AN ELEVATED INVERSION AROUND 750 MB WHICH COULD MAKE LIFE INTERESTING AS THE LOWER ELEVATIONS AIR STARTS TO COOL DOWN ALL DAY FRIDAY THERE MAY BE AN WINDOW FRIDAY MORNING WHERE THERE IS RAIN AROUND 6-8K MSL AND FREEZING RAIN IN THE VALLEYS. NEVERTHELESS FRIDAY POSES A WINTRY MIX PROBLEM AND I HOPE FOR NOW THE COLUMN OF AIR FROM 850 TO 700 MB COOLS FAST TO AVOID A POTENTIAL FREEZING RAIN/ICE PROBLEM FOR FRIDAY. HOPEFULLY THIS WINDOW WILL BE SMALL AND WE WILL TRANSITION INTO THE DAY WITH A MIX OF RAIN AND SLEET INTO SNOW AS THE TEMPERATURE DROPS. AT THE MOMENT WE ARE CALCULATING FROM BOTH MODELS SOME UNBELIEVABLE SNOW AMOUNTS WITH 12-15+ INCHES FOR THE MOUNTAINS AND 6 - 12 INCHES EVEN IN THE LOWLANDS FOR FRIDAY EVENING AND SATURDAY. HENCE SPS ISSUED FOR HEADS UP. TROPA NOW SCHEDULED FOR 06Z SUNDAY SO CLEARING IT OUT LATE SATURDAY. THEN TO MAKE LIFE MORE INTERESTING...THE 12Z GFS HAS ANOTHER SYSTEM DROPPING INTO THE CWA WITH PRECIP FOR NEXT MONDAY AND TUESDAY...NOT IN THE ZONES AT THIS TIME && .AVIATION... VALID 17/00Z TO 18/00Z. WK DIST DVLPG OFF STG JET S OF INTERNATIONAL BORDER...WL CONT TO SPRD STRATUS/CIGS TO FL090 ACRS ALL TAF SITES THRU ERLY TMRW MRNG. WDSPRD CIGS WL CONT ACRS TWB RTE 196 FM KELP-KLSB...AND RTE 195 FM KELP-50N KTCS THRU THRU MOST OF THE EVNG. -SHSN PSBLE AT ELP AND VCNTY DMN AFT MIDNIGHT. CIGS WL BEGIN TO DISSIPATE ALL AREAS LTR TMRW MRNG. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 21 45 26 52 35 / 10 10 10 20 30 SIERRA BLANCA TX 15 39 25 49 28 / 20 10 10 20 30 LAS CRUCES 19 45 23 51 34 / 10 10 0 20 30 ALAMOGORDO 16 45 22 49 35 / 10 10 0 20 30 CLOUDCROFT 7 30 13 45 18 / 10 10 0 20 30 TRUTH OR CONSEQUENCES 18 43 21 49 31 / 10 10 0 10 30 SILVER CITY 13 41 19 48 29 / 0 0 0 10 30 DEMING 18 44 23 51 33 / 0 0 0 20 30 LORDSBURG 18 46 21 51 29 / 0 0 0 10 30 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 20 / NOVLAN 22 / TRIPOLI AVIATION tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 259 PM CST TUE JAN 16 2007 .DISCUSSION...FORECAST FOCUS ON TEMPERATURES AND NEXT WEATHER SYSTEM. .SHORT TERM...WEATHER NIL AS RUC/NGM/NAM/GFS PROGS TAKE CENTER OF SURFACE HIGH OVER IOWA AND MISSOURI AND SLIDE IT TO THE OHIO VALLEY BY WEDNESDAY. EXPECT SURFACE PRESSURE GRADIENT TO RELAX AND WINDS TO DECOUPLE SHORTLY AFTER SUNSET. TEMPERATURES WILL RAPIDLY FALL EARLY TONIGHT AND THEN STEADY OUT AS PROGS INDICATE WARM AIR ADVECTION KICKING IN. BUT DESPITE WARM AIR ADVECTION FEEL COMBINATION OF CLEAR SKIES...LIGHT WINDS AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO GO BELOW GUIDANCE VALUES...ESPECIALLY WITH DEW POINTS ALREADY IN SINGLE DIGITS. .LONG TERM...NEXT WEATHER SYSTEM TO AFFECT CWA ON THURSDAY WITH PROGS AGREEING THAT MOST ENERGY CONFINED NORTH OF CWA. WITH GULF OF MEXICO SHUT DOWN...AVAILABLE MOISTURE IS QUITE SPARSE ON TIME CROSS SECTIONS. THUS HAVE KEPT SNOW CHANCES SMALL FOR NOW. THEN A COLD DRY PERIOD EXPECTED INTO THE WEEKEND AS ANOTHER HIGH SETTLES INTO REGION. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ZAJDEL wi