AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 925 PM MST MON JAN 10 2005 .DISCUSSION...INTERESTING SHORT TERM DEVELOPMENTS THIS EVENING AS SYSTEMS OVER CALIFORNIA AND NEVADA MERGE AND PUSH INTO THE NORTHERN GREAT BASIN. LATEST SATELLITE AND RADAR IMAGES INDICATE SNOW EXPANDING IN AREAL EXTENT OVER THE NORTHERN THIRD OF NEVADA AND PUSHING ACROSS THE SOUTHERN IDAHO BORDER. LATEST MESO ANALYSIS SHOWS GREATEST PRESSURE FALLS ALONG AND TO THE NORTH OF A STATIONARY FRONTAL BOUNDARY ROUGHLY PARALLEL TO I-80 ACROSS NEVADA. LOOKING AT LATEST RUC AND MESO12 DETAILS PLACES A BAND OF MODERATE TO OCCASIONALLY HEAVY SNOW AFTER MIDNIGHT ALONG THE NEVADA BORDER AND TENDING TO LIFT NORTH INTO THE SNAKE RIVER PLAIN BY 12Z. MODELED WATER EQUIVALENTS TRANSLATE INTO 1 TO 3 INCH SNOW AMOUNTS WITH POSSIBLY UP TO 4 OR 5 INCHES IN A FEW PLACES. STILL NOT QUITE SURE HOW FAR NORTH SNOW BAND WILL MOVE ON TUESDAY BUT IF STRONG CALIFORNIA UPPER LOW MOVES NORTH OF 40N DURING THE NIGHT AND IS STILL ABLE TO TAP INTO SUBTROPICAL PLUME COMING ACROSS CENTRAL CALIFORNIA...THEN SNOW WILL BECOME WIDESPREAD ACROSS A LARGER AREA ON TUESDAY AND FARTHER NORTH AS WELL. CURRENT GRIDS AND SOUTHERN ZONES NEED TO BE UPDATED FOR HIGHER QPF AND SNOW AMOUNTS. ALREADY COORDINATED DECISIONS WITH MFR/EKN/AND PIH WHO ALL HAVE WINTER HIGHLIGHTS IN PLACE FOR THIS AREA. ZONE UPDATES FORTHCOMING. && .AVIATION...LOW CLOUDS AND PATCHY DENSE FOG WILL CONTINUE TONIGHT OVER THE BAKER VALLEY FOR IFR CONDITIONS THROUGH MORNING. THE MAGIC VALLEY WILL BATTLE MUCH OF THE NIGHT INTO TOMORROW MORNING WITH IFR CONDITIONS AS WELL...HOWEVER CONDITIONS WILL IMPROVE TEMPORARILY TO MVFR WITH ASSOCIATED WITH SNOW SHOWERS. LOCAL IFR CONDITIONS IN VALLEY PORTIONS OF THE BOISE AND WEST CENTRAL MOUNTAINS...AND THE LOWER TREASURE VALLEY ARE EXPECTED TO DEVELOP AFTER 06Z. ELSEWHERE VFR CONDITIONS WITH PERIODICALLY MVFR ACROSS THE SOUTH IN LIGHT SNOW SHOWERS. && .PREVIOUS DISCUSSION...FOR SOUTHWEST IDAHO AND SOUTHEAST OREGON TONIGHT THROUGH THURSDAY. OUR AREA WAS BETWEEN TWO SYSTEMS MONDAY AFTERNOON. THE 1ST WAS THE COMMA HEAD OF A LARGE DEPARTING SYSTEM OVER UTAH. CLOUDS AND A FEW SHOWERS FAVORED OUR SOUTHERN MOST ZONES DURING THE AFTERNOON. EXPECT THAT FEATURE TO EXIT BY TUESDAY MORNING. THE 2ND SYSTEM WAS UPSTREAM JUST OFF THE NORTHERN CA COAST. THIS SYSTEM WILL MOVE INLAND TONIGHT AND BE CENTERED WELL SOUTH OF OUR AREA TUESDAY. HOWEVER...CLOUDS AND SHOWERS WILL SPREAD INTO OUR SOUTHERN ZONES DURING THE DAY ON TUESDAY THEN EXIT BY TUESDAY EVENING. THE FOCUS THEN SHIFTS TO OUR NORTH AS A MODIFIED ARCTIC FRONT BEGINS DROPPING SOUTHWARD LATE TUESDAY NIGHT FOR INCREASING POPS FAVORING OUR NORTHERN ZONES INTO WEDNESDAY NIGHT. WILL CONTINUE LOW POPS ON THURSDAY BEHIND THE FRONT FAVORING THE MOUNTAINS. THE COOLING TREND BEGINS ON TUESDAY AND CONTINUES THROUGH THURSDAY. DAYTIME HIGHS WILL BE NORMAL ON TUESDAY...A COUPLE DEGREES BELOW NORMAL ON WEDNESDAY THEN ABOUT 10 DEGREES BELOW NORMAL ON THURSDAY. && .LONG TERM...THURSDAY NIGHT THRU MONDAY. WITH MODIFIED ARCTIC AIR IN PLACE BY THURSDAY NIGHT AND MOSTLY CLEAR SKIES UNDER STRONG SURFACE HIGH PRESSURE...EXPECT FRIDAY MORNING TO BE COLDEST OF WEEK...AND POSSIBLY COLDEST OF SEASON SO FAR. HIGH TEMPERATURES WILL STRUGGLE TO WARM ON FRIDAY AND EVEN THOUGH MODELS ALREADY SHOWING SIGNS OF UPPER RIDGE BUILDING OVER PACIFIC NORTHWEST LATE THURSDAY AS 500MB BEGIN TO THE RISE...WARMING ISN/T REALIZED AT SURFACE UNTIL SATURDAY AT THE EARLIEST. RIDGE CONTINUES TO AMPLIFY OVER THE PACIFIC NORTHWEST INTO THE WEEKEND. MODELS SEEM TO BE IN GOOD AGREEMENT ABOUT PATTERN CHANGE FOR EARLY NEXT WEEK...WHICH WOULD PUT AREA UNDER AN INVERSION. STILL SOME DIFFERENCES ON STRENGTH OF WARMING ALOFT BUT WITH LOW LEVEL COLD AIR TRAPPED IN THE VALLEYS IT WON/T TAKE MUCH WARMING ALOFT TO SET UP INVERSION. FOR NOW HAVE KEPT FOG AND PARTLY CLOUDY WORDING IN FORECAST STARTING FRIDAY MORNING. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...NONE. OR...NONE. && $$ WWW.WEATHER.GOV/BOISE DISCUSSION...GS AVIATION.....RH PREVIOUS DISCUSSION...TE LONG TERM....DG id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 825 PM CST MON JAN 10 2005 ...DISCUSSION... QUITE A FEW FORECAST CONCERNS THIS EVENING...RANGING FROM TEMPERATURES TO FOG TO CHANCES FOR FREEZING PCPN IN THE NORTH. 00Z SFC CHART SHOWING A COMPLICATED SFC PATTERN ACROSS THE AREA. WHAT APPEARS TO BE THE PRIMARY WARM FRONT IS LOCATED ACROSS SOUTHERN IL AND SOUTHERN MO. ANOTHER BOUNDARY STRETCHES NE OUT OF MO AND ACROSS NORTH CENTRAL IL...THIS SEEMS TO BE MORE OF A STATIONARY FRONT WITH TEMPS IN THE UPPER 20S ACROSS NORTHERN IL ON THE NORTH SIDE AND IN THE LOWER 30S JUST SOUTH OF THE BOUNDARY FROM RUFFLY GBG TO PIA TO IKK. TEMPERATURES ARE IN THE LOWER TO MIDDLE 30S THIS EVENING ACROSS MOST OF NORTH CENTRAL AND CENTRAL IL. TEMPS ARE PRETTY MUCH REMAINING STEADY AND EXPECT THIS TO BE THE CASE TONIGHT...MAYBE EVEN RISE A FEW DEGREES TOWARD MORNING. TEMPERATURES ARE IN THE UPPER 30S TO AROUND 40 ALONG AND SOUTH OF I-70. RADAR SHOWING THAT PCPN IS BREAKING OUT IN BANDS AND MOVING QUICKLY TO THE NE. HIGH REFLECTIVITIES ON SOME OF THE RETURNS INDICATING SOME SLEET A GOOD POSSIBILITY...ESP ACROSS THE NORTH. PIA DID REPORT SOME SLEET FOR A BRIEF TIME EARLIER. MEANWHILE FOG AND LOW CEILINGS AND DRIZZLE BECOMING MORE OF A CONCERN...WITH VISIBILITIES DOWN TO 1/4 TO 1/2 OF A MILE IN QUITE A FEW LOCATIONS. AS FAR AS FREEZING RAIN AND THE WINTER WEATHER ADVISORY ACROSS THE NORTH TONIGHT...I PLAN ON NO CHANGES TO THIS AT THIS TIME. WHILE SOME ICING IS POSSIBLE TONIGHT...I DONT THINK WE ARE LOOKING AT ANY KIND OF A MAJOR EVENT. AND TEMPS MAY RISE ENUFF BY MORNING THAT THINGS MAY REMAIN UN-FROZEN...BUT NOT CONFIDENT ENUFF IN THAT TO MAKE ANY CHANGES AT THE MOMENT. WILL UPDATE ZONES SHORTLY TO FRESHEN UP THE WORDING SOME...WILL MAKE MENTION OF NEARLY STEADY TEMPERATURES...WILL ADD FOG...LOCALLY DENSE AT TIMES BUT DONT THINK IT WILL STAY PEA SOUP ALL NIGHT OR REAL WIDESPREAD FOR AN EXTENDED PERIOD OF TIME...SO WILL STOP JUST SHORT OF AN ADVISORY. && .PREV DISCUSSION... MODELS IN FAIRLY GOOD AGREEMENT WITH MASS FIELDS IN THE SHORT TERM AND SEEMED TO VERIFY FINE EXCEPT FOR SFC TEMPS. BOTH GFS AND ETA STARTED THE DAY AROUND 5 DEGREES TOO COOL IN NORTHERN AREAS OF CWA. THIS CRITICAL TO FCST SINCE BIGGEST CHALLENGE THIS PACKAGE WILL BE POSSIBILITY OF FREEZING PCPN TONIGHT AND TOMORROW MORNING. OTHER CHALLENGES WILL BE TEMPS AND CHANCE OF THUNDERSTORMS NEXT SEVERAL DAYS. OTHER CONCERN IS CHANCE OF HEAVY RAIN WED NIGHT AND THUR. MODELS DIFFER WITH MAIN WAVE COMING ON WED THROUGH THUR. GFS COMES OUT FASTER AND STRONGER WITH THE WAVE WHILE THE EAT IS SLOWER AND WEAKER. THIS HAS A SIGNIFICANT AFFECT ON THE TIMING OF THE FRONT FOR THUR...THE AMOUNT OF WARM AIR AND MOISTURE MOVING INTO THE AREA PRIOR TO THE SYSTEM. WILL LIKELY TAKE A BLEND OF THE MODELS AS FAR AS SPEED AND STRENGTH OF SYSTEM AND SEE WHAT THINGS LOOK LIKE TOMORROW. SHORT TERM...TONIGHT THROUGH THURSDAY... WARM FRONT CRNTLY EXTENDS FROM OK INTO MO AND NWRN IL. THIS FURTHER NORTH THAN ALL MODELS INDICATE...EXCEPT FOR RUC. IN TURN...WARMER AIR SLOWLY ADVECTING NORTHWARD INTO THE AREA AND TEMPS HAVE RISEN COUPLE OF DEGS THIS AFTERNOON. PRSS FALLS HAVE ALSO BEEN HIGH WITH THE FIRST WAVE WHICH INDICATES GOOD WAA. SLOWLY MOVING INTO THE WESTERN PARTS OF THE CWA...BUT NOT MUCH REACHING THE GROUND AT THIS TIME. AIR MASS ABOVE THE INVERSION RELATIVELY DRY...SO MAY TAKE SOME TIME BEFORE PCPN STARTS REACHING THE GROUND. SO WILL START WITH CHC PCPN TONIGHT AND INCREASE TO LIKELY AFTER MIDNIGHT. DUE TO WARMER AIR IN LOWER LVLS...WILL HAVE ZR- ONLY IN NORTHERN THREE COUNTIES AND HAVE RAIN ELSEWHERE. WILL ALSO MENTION CHC OF THUNDER IN THE CNTRL AND SOUTH FOR OVERNIGHT AS ELEVATED THUNDERSTORMS ARE POSSIBLE JUST NORTH OF A SECONDARY FRONT THAT WILL BE LIFTING NORTHWARD OVERNIGHT. AS FRONT MOVES THROUGH THE AREA TOMORROW...STATIONARY FRONT WILL SETUP ACRS SRN IL. DYNAMICS AND LIFT REMAIN CONFINED TO THE FRONT TOMORROW AND TOMORROW NIGHT...SO RAIN AND CHC OF THUNDER WILL CONTINUE DURING THE DAY TOMORROW IN THE CNTRL AND SOUTH WHILE CHC OF PCPN WILL DECREASE ACRS THE NORTH. PCPN UP NORTH WILL BE ALL RAIN AS TEMPS WILL REMAIN WARM...OR CONTINUE TO WARM. MAIN SYSTEM WILL BEGIN TO LIFT OUT ON WED AND ADVECT MUCH WARMER AIR INTO THE AREA AND PLENTY OF MOISTURE. DYNAMICS INCREASE FOR WED AND INTO WED NIGHT WHILE INSTABILITY PARAMETERS SUPPORT ISOLATED THUNDERSTORMS DURING THE DAY AND NIGHT AS WELL. RAIN COULD ALSO BE ON THE HEAVY SIDE WITH PW VALUES WELL ABOVE NORMAL AND MODELS SPITTING OUT QPF AROUND AN INCH IN 6 HRS. THIS WILL AGGRAVATE ALREADY SWOLLEN RIVERS AND WITH FLOODING ALREADY ONGOING HAVE OPTED OUT OF ISSUING AN ESF FOR THE AREA. FFA WILL LIKELY BE NEEDED FOR THAT TIME FRAME IF MODELS REMAIN CONSISTENT WITH AMOUNT OF QPF FOR WED NIGHT. HOWEVER...WILL WAIT FOR TWO MORE MDL RUNS TO SEE AND IF NECESSARY WILL LIKELY ISSUE FFA TOMORROW AFTERNOON. PER BLEND OF GFS AND ETA...SYSTEM WILL PUSH THROUGH DURING WED NIGHT/THUR MORNING. RAIN SHOULD QUICKLY CHANGE OVER TO SNOW AS COLDER AIR MOVES IN RIGHT AFTER THE FRONT. THIS WILL CAUSE TEMPS ON THUR TO BE FALLING WITH MOST AREAS SEEING HIGHS IN THE MORNING. AMOUNT OF SNOWFALL FOR THUR WILL BE QUESTIONABLE AND DEPEND ON TRACK OF LOW. WITH MODELS DIFFERING AT THIS TIME WILL ONLY HAVE CHC OF SNOW DURING ON THUR. TEMPS TRICKY WITH LOTS OF CLOUDS...WAA AND PCPN IN MOST PERIODS. TRIED TO FOLLOW A BLEND OF MAV AND MET GUIDANCE. LONG TERM...FRIDAY THROUGH MONDAY... EXTENDED WILL SEE A PATTERN CHANGE WITH AREA SEEING CYCLONIC/NORTHWESTERLY FLOW THROUGH MONDAY. THIS WILL BRING IN VERY COLD AND DRY AIR TO THE AREA THROUGH THE PERIOD. THEREFORE HAVE KEPT A DRY FORECAST GOING THROUGH THE PERIOD. GUIDANCE TEMPS LOOK REASONABLE FOR FRI AND SAT BUT BELIEVE MEX WARMS THINGS TOO QUICKLY...SO UNDERCUT TEMPS FOR SUN AND MON. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY TONIGHT FOR KNOX...MARSHALL AND STARK COUNTIES && $$ HALL il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 300 PM CST MON JAN 10 2005 .DISCUSSION... MODELS IN FAIRLY GOOD AGREEMENT WITH MASS FIELDS IN THE SHORT TERM AND SEEMED TO VERIFY FINE EXCEPT FOR SFC TEMPS. BOTH GFS AND ETA STARTED THE DAY AROUND 5 DEGREES TOO COOL IN NORTHERN AREAS OF CWA. THIS CRITICAL TO FCST SINCE BIGGEST CHALLENGE THIS PACKAGE WILL BE POSSIBILITY OF FREEZING PCPN TONIGHT AND TOMORROW MORNING. OTHER CHALLENGES WILL BE TEMPS AND CHANCE OF THUNDERSTORMS NEXT SEVERAL DAYS. OTHER CONCERN IS CHANCE OF HEAVY RAIN WED NIGHT AND THUR. MODELS DIFFER WITH MAIN WAVE COMING ON WED THROUGH THUR. GFS COMES OUT FASTER AND STRONGER WITH THE WAVE WHILE THE EAT IS SLOWER AND WEAKER. THIS HAS A SIGNIGICANT AFFECT ON THE TIMING OF THE FRONT FOR THUR...THE AMOUNT OF WARM AIR AND MOISTURE MOVING INTO THE AREA PRIOR TO THE SYSTEM. WILL LIKELY TAKE A BLEND OF THE MODELS AS FAR AS SPEED AND STRENGTH OF SYSTEM AND SEE WHAT THINGS LOOK LIKE TOMORROW. SHORT TERM...TONIGHT THROUGH THURSDAY... WARM FRONT CRNTLY EXTENDS FROM OK INTO MO AND NWRN IL. THIS FURTHER NORTH THAN ALL MODELS INDICATE...EXCEPT FOR RUC. IN TURN...WARMER AIR SLOWLY ADVECTING NORTHWARD INTO THE AREA AND TEMPS HAVE RISEN COUPLE OF DEGS THIS AFTERNOON. PRSS FALLS HAVE ALSO BEEN HIGH WITH THE FIRST WAVE WHICH INDICATES GOOD WAA. SLOWLY MOVING INTO THE WESTERN PARTS OF THE CWA...BUT NOT MUCH REACHING THE GROUND AT THIS TIME. AIR MASS ABOVE THE INVERSION RELATIVELY DRY...SO MAY TAKE SOME TIME BEFORE PCPN STARTS REACHING THE GROUND. SO WILL START WITH CHC PCPN TONIGHT AND INCREASE TO LIKELY AFTER MIDNIGHT. DUE TO WARMER AIR IN LOWER LVLS...WILL HAVE ZR- ONLY IN NORTHERN THREE COUNTIES AND HAVE RAIN ELSEWHERE. WILL ALSO MENTION CHC OF THUNDER IN THE CNTRL AND SOUTH FOR OVERNIGHT AS ELEVATED THUNDERSTORMS ARE POSSIBLE JUST NORTH OF A SECONDARY FRONT THAT WILL BE LIFTING NORTHWARD OVERNIGHT. AS FRONT MOVES THROUGH THE AREA TOMORROW...STATIONARY FRONT WILL SETUP ACRS SRN IL. DYNAMICS AND LIFT REMAIN CONFINED TO THE FRONT TOMORROW AND TOMORROW NIGHT...SO RAIN AND CHC OF THUNDER WILL CONTINUE DURING THE DAY TOMORROW IN THE CNTRL AND SOUTH WHILE CHC OF PCPN WILL DECREASE ACRS THE NORTH. PCPN UP NORTH WILL BE ALL RAIN AS TEMPS WILL REMAIN WARM...OR CONTINUE TO WARM. MAIN SYSTEM WILL BEGIN TO LIFT OUT ON WED AND ADVECT MUCH WARMER AIR INTO THE AREA AND PLENTY OF MOISTURE. DYNAMICS INCREASE FOR WED AND INTO WED NIGHT WHILE INSTABILITY PARAMETERS SUPPORT ISOLATED THUNDERSTORMS DURING THE DAY AND NIGHT AS WELL. RAIN COULD ALSO BE ON THE HEAVY SIDE WITH PW VALUES WELL ABOVE NORMAL AND MODELS SPITTING OUT QPF AROUND AN INCH IN 6 HRS. THIS WILL AGGRAVATE ALREADY SWOLLEN RIVERS AND WITH FLOODING ALREADY ONGOING HAVE OPTED OUT OF ISSUING AN ESF FOR THE AREA. FFA WILL LIKELY BE NEEDED FOR THAT TIME FRAME IF MODELS REMAIN CONSISTANT WITH AMOUNT OF QPF FOR WED NIGHT. HOWEVER...WILL WAIT FOR TWO MORE MDL RUNS TO SEE AND IF NECESSARY WILL LIKELY ISSUE FFA TOMORROW AFTERNOON. PER BLEND OF GFS AND ETA...SYSTEM WILL PUSH THROUGH DURING WED NIGHT/THUR MORNING. RAIN SHOULD QUICKLY CHANGE OVER TO SNOW AS COLDER AIR MOVES IN RIGHT AFTER THE FRONT. THIS WILL CAUSE TEMPS ON THUR TO BE FALLING WITH MOST AREAS SEEING HIGHS IN THE MORNING. AMOUNT OF SNOWFALL FOR THUR WILL BE QUESTIONABLE AND DEPEND ON TRACK OF LOW. WITH MODESL DIFFERING AT THIS TIME WILL ONLY HAVE CHC OF SNOW DURING ON THUR. TEMPS TRICKY WITH LOTS OF CLOUDS...WAA AND PCPN IN MOST PERIODS. TRIED TO FOLLOW A BLEND OF MAV AND MET GUIDANCE. LONG TERM...FRIDAY THROUGH MONDAY... EXTENDED WILL SEE A PATTERN CHANGE WITH AREA SEEING CYCLONIC/NORTHWESTERLY FLOW THROUGH MONDAY. THIS WILL BRING IN VERY COLD AND DRY AIR TO THE AREA THROUGH THE PERIOD. THEREFORE HAVE KEPT A DRY FORECAST GOING THROUGH THE PERIOD. GUIDANCE TEMPS LOOK REASONABLE FOR FRI AND SAT BUT BELIEVE MEX WARMS THINGS TOO QUICKLY...SO UPDERCUT TEMPS FOR SUN AND MON. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY TONIGHT FOR KNOX...MARSHALL AND STARK COUNTIES && $$ AUTEN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1115 AM MST MON JAN 10 2005 .DISCUSSION...CALLS AROUND TO LOCAL LAW ENFORCEMENT OFFICIALS INDICATE THAT FOR THE MOST PART VISIBILITY HAS IMPROVED TO GREATER THAN A 1/4 MILE IN THE ADVISORY AREA. ASOS OBSERVATIONS HAVE ALSO IMPROVED IN BURLINGTON AND GOODLAND TO AROUND 1 MILE. THEREFORE HAVE ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AT 11 AM MST. HOWEVER...WILL CONTINUE TO HIT NOWCASTS HARD AS PATCHY DENSE FREEZING FOG WILL CONTINUE ALONG THE LEADING EDGE OF THE ARCTIC AIR...IN THE 4 COUNTY AREA OF KIT CARSON AND CHEYENNE IN COLORADO AND SHERMAN AND WALLACE IN KANSAS. ALSO TOOK THE OPPORTUNITY TO LOWER TODAYS HIGHS ANOTHER CATEGORY OR SO ACROSS THE ENTIRE AREA AS CLOUDS/FOG HAVE KEPT TEMPERATURES NEARLY STEADY ALL MORNING. VISIBLE SATELLITE CLEARLY DEFINES LOCATION OF THE FRONT FROM NEAR ELKHART KANSAS TO LAMAR COLORADO...THEN WEST TO LA JUNTA. SOME RETREAT NOTED IN THE LAST HOUR OR SO ON ITS SOUTHERN END...BUT WILL BE HARD PRESSED TO MAKE BACK INTO SOUTHERN PARTS OF THE FORECAST AREA. CLOUDS AND EASTERLY UPSLOPE WILL BE DOMINATE...AND WENT CLOSE TO THE RUC ON TEMPERATURES WHICH IS PERFORMING EXCELLENTLY AT THE MOMENT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 909 AM MST MON JAN 10 2005 .DISCUSSION...12Z ANALYSIS PLACED FRONTAL BOUNDARY ACROSS THE EASTERN PLAINS OF COLORADO...JUST WEST OF LIMON. ONLY MODEL THAT SEEMS TO HAVE A HANDLE WAS THE 15Z RUC. ALL OTHER MODELS TOO FAR EAST WITH THE FRONT AND THUS TOO WARM. THIS UPDATE WILL LOWER HIGH TEMPERATURES TO THE LOWER 30S TO THE COLORADO BORDER...FOLLOWING THE RUC. FURTHER EAST THE RUC HOLDS TEMPERATURES IN THE LOWER 20S ALL DAY. HOWEVER LEFT THAT AREA ALONE FOR NOW SINCE CURRENT FORECAST WITHIN 5 DEGREES ANYWAY. NOT VERY COMFORTABLE WITH THE FREEZING DRIZZLE WORDING IN THE ZONES...SINCE NONE BEING REPORTED...BUT THEN AGAIN THE DISTINCTION BETWEEN FREEZING FOG AND FREEZING DRIZZLE IS DEBATABLE. FURTHER UPDATES WILL MOST LIKELY BE NEEDED TO REFLECT RAPIDLY CHANGING CONDITIONS WITH FOG/DRIZZLE AND TEMPERATURES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...DENSE FOG ADVISORY UNTIL 18Z THIS MORNING..CHEYENNE..SHERMAN..WALLACE COUNTIES. NE...NONE. CO...DENSE FOG ADVISORY UNTIL 18Z THIS MORNING..YUMA..KIT CARSON COUNTIES. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 928 PM EST MON JAN 10 2005 .UPDATE... THE 00Z UPPER AIR PLOTS SHOWED A 130KT 300MB JET NEAR GEORGIAN BAY. ENTRANCE REGION DYNAMICS IS AIDING SOME MID FRONTOGENETICAL LIFT ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES... ALONG AND NORTH OF A FRONT OVER THE OHIO VALLEY. AREA RADARS SHOW TWO MAIN BANDS OF RETURNS ASSOCIATED WITH THIS LIFT. ONE EXTENDS FROM NEAR MSP TO CENTRAL MICHIGAN... WITH ONLY FLURRIES BEING REPORTED. THE SECOND AREA OF RETURNS ARC FROM SOUTHERN IOWA ACROSS NORTHERN IL TO CENTRAL IN. MAINLY RA AND FZRA IS OCCURRING WITH THIS FEATURE. THE HIGH PRESSURE OVER THE NORTHERN GREAT LAKES IS A LITTLE STRONGER THAN INDICATED BY EARLIER MODEL RUNS. THE 00Z SOUNDINGS FOR APX/GRB/DTX/DVN ALL WERE A LITTLE BIT DRYER BELOW 700MB AS A RESULT. MEANWHILE... THE 12Z AND 18Z RUC AND ETA VERIFIED THE THERMAL STRUCTURE ACROSS THE REGION RATHER WELL. FOR THE CURRENT ADVISORY... FEEL THERE WILL BE A LITTLE BIT MORE SNOW TO START THE EVENT THEN PREVIOUSLY THOUGHT. THIS IS DUE TO SLIGHTLY LOWER WET BULB HEIGHTS OVER SOUTHERN MICHIGAN. PERSISTENT MID LEVEL FRONTOGENETICAL LIFT OVER THE SOUTHERN LAKES SHOULD ALSO TIGHTEN THE THERMAL GRADIENT OVER THE OHIO VALLEY... WITH AGEOSTROPHIC FLOW HELPING TO ADVECT COLDER AIR INTO THE ADVISORY AREA. LIFT IS STILL EXPECTED TO MOVE INTO THE ADVISORY AFTER 06Z AND PERSIST OFF AND ON THROUGH 18Z TUE. THE WARM LAYER WILL SLOWLY LIFT NORTHWARD ON TUESDAY... CAUSING A GRADUAL CHANGE OVER TO SLEET AND FREEZING RAIN BY NOON... THEN ALL RAIN BY LATE AFTERNOON. BASED ON OBSERVATIONS AND LATEST GUIDANCE... WILL INCREASE TOTAL SNOWFALL TO 2 TO 4 INCHES AND EXPAND THE ADVISORY TO 2 PM TUES. WITH SPECIFIC HUMIDITIES OF 4 G/KG OVER THE SOUTH... LENAWEE AND MONROE COUNTIES MAY APPROACH WARNING CRITERIA TUES MORNING IF THE CHANGE OVER TO SLEET AND FZRA IS LATER. AS FOR THE M 59 COUNTIES... THE SOUNDING PROFILE LOOKS MAINLY LIKE SNOW THROUGH NOON TUES. WILL HOWEVER CUT BACK ACCUMULATIONS TO 1 TO 3 INCHES AS IT APPEARS THE BEST FRONTOGENETICAL FORCING TONIGHT WILL BE BOTH NORTH AND SOUTH OF THESE COUNTIES. MODEST LIFT WILL OCCUR TUES MORNING... BUT IS EXPECTED TO BE MUCH WEAKER THAN IN THE ADVISORY AREA. AND FOR I 69 COUNTIES AND POINTS NORTHWARD... THE AMOUNT OF DRY AIR ASSOCIATED WITH THAT HIGH WILL LIMIT THE AMOUNT OF SNOWFALL ACCUMULATION. I WILL THUS LOWER SNOWFALL CHANCES AND AMOUNTS CONSIDERABLY. LACK OF ANY SIGNIFICANT SNOWFALL REPORTS UPSTREAM SUPPORTS THIS. FOR TONIGHT/TUES MORNING... I WILL CARRY ACCUMULATIONS AN INCH OR LESS. THE UPDATED ZONES AND GRIDS WILL BE AVAILABLE BY 330 UTC (1030 PM). THANKS FOR THE COORDINATION GRR. && .AVIATION... ISSUED AT 640 PM. LOW PRESSURE OVER SOUTHERN MISSOURI WILL MOVE EAST ACROSS THE MID MISSISSIPPI VALLEY TONIGHT... THEN ACROSS THE OHIO VALLEY ON TUESDAY. THE LATEST SATELLITE DATA IS SHOWING COOLING CLOUD TOPS ACROSS THE UPPER MIDWEST... WITH DEEP MOISTURE SLOWLY ADVANCING EAST TOWARD THE GREAT LAKES. THIS MOISTURE WILL MOVE ACROSS SE MICHIGAN OVERNIGHT. THERE WILL ALSO BE SOME MODEST MID LEVEL FRONTOGENETICAL LIFT WITHIN THE ENTRANCE REGION OF AN UPPER JET. THIS WILL ALLOW PRECIPITATION TO DEVELOP OVERNIGHT. THE LIFT WILL CONTINUE THROUGH TUESDAY MORNING AND BE STRONGEST SOUTH OF M 59. THE HIGH PRESSURE CENTERED OVER NORTHERN MINNESOTA AND THE NORTHERN GREAT LAKES HAS ALLOWED TEMPS TO LOWER A BIT MORE THAN MODELS INDICATE. THUS TEND TO BELIEVE THE 18Z MODEL RUNS WHICH SHOW MOST OF THE PRECIP FALLING ACROSS SOUTHERN MICHIGAN OVERNIGHT TO BE IN THE FORM OF SNOW. I WILL NOT BRING SLEET AND FREEZING RAIN INTO DTW/DET UNTIL AFTER 14Z TUESDAY WHEN WARM AIR ALOFT FINALLY PUSHES INTO SOUTHERN MICHIGAN. FOR THE TIME BEING... BASED ON WANING LIFT IN THE NORTH... WILL LEAVE FNT AND MBS DRY AFTER 17Z. WILL CONTINUE TO TREND CEILINGS DOWNWARD OVERNIGHT AS THE MOISTURE INCREASES. BASED ON THE LOCATION OF STRONGEST LIFT... CEILINGS AND VISIBILITIES WILL BE LOWER AT DTW AND DET IN COMPARISON TO FNT AND MBS. && .SHORT TERM... ISSUED AT 350 PM. STORM SYSTEM OVER SW MISSOURI TO TRACK THROUGH THE OHIO VALLEY TONIGHT...DELIVERING A BURST OF PRECIPITATION TO SOUTHERN LOWER MICHIGAN OVERNIGHT INTO TOMORROW MORNING. LATEST WATER VAPOR IMAGERY INDICATING MID LEVEL MOISTURE BEGINNING TO STREAM INTO THE SOUTHERN GREAT LAKES. BEST ISENTROPIC LIFT (285-290 K) LOOKS TO BE OCCURRING AROUND 9Z OVER SW LOWER...AND AROUND 12Z OVER SOUTHEAST MICHIGAN. SPECIFIC HUMIDITIES CLIMB OVER 4 G/KG OVER THE SOUTHERN MICHIGAN BORDER...WITH AROUND 3 G/KG OVER CENTRAL LOWER MICHIGAN. BIG DIFFERENCES BETWEEN 12Z ETA/GFS. ETA INDICATING TWO DISTANT REGIONS OF LIFT (SEE 700 MB OMEGA)...ONE IN THE NORTH (KLDM-KMBS) AND THE MORE SIGNIFICANT FORCING IN THE TOWARD THE OHIO BORDER. 24 HOUR (18Z MONDAY-18Z TUESDAY) QPF TOTALS OUT OF GFS RANGE FROM 5 HUNDREDTHS NORTH TO 4 TENTHS OF AN INCH SOUTH. 12Z MESOETA IS A LOT MORE BULLISH WITH QPF FARTHER NORTH...INDICATING 0.15 INCHES TO 0.35 INCHES NORTH OF I-94. EVEN SO...ETA BUFKIT PROFILES INDICATE SATURATION WILL GENERALLY BE BELOW -10 C ISOTHERM...THUS WOULD NOT EXPECT HIGH SNOW TO LIQUID RATIOS. ALL SOUNDINGS (GFS/ETA/NGM/UKMET) POINT TO ALL SNOW NORTH OF I-94 TONIGHT...WITH ENOUGH WARM AIR COMING IN THE 2000 TO 5000 FOOT LAYER TO ALLOW FOR A MIX AND/OR CHANGEOVER TO SLEET AND FREEZING RAIN TOWARD THE SOUTHERN MICHIGAN BORDER. BECAUSE OF THIS WINTRY MIX...WILL ISSUE A WINTER WEATHER ADVISORY FOR I-94 CORRIDOR AND POINTS SOUTH. EXPECTING 1 TO 3 INCHES BEFORE THE CHANGEOVER OCCURS. HELD OFF ON ANY ADVISORY'S FARTHER NORTH...AS THE PRECIPITATION SHOULD BE ALL SNOW INTO TUESDAY MORNING. WILL CARRY ACCUMULATIONS OF 1 TO 4 INCHES IN THE ZONES NORTH OF I-94...BELOW ADVISORY CRITERIA. LIFT EXITS THE REGION TUESDAY MORNING...WITH SHORTWAVE RIDGING BUILDING IN FOR THE AFTERNOON HOURS. DEEP LOW LEVEL MOISTURE SUPPORTS A MENTION OF DRIZZLE...WITH LOCATIONS ALONG AND NORTH OF I-96 AT OR SLIGHTLY BELOW FREEZING FOR MUCH OF THE DAY. && .LONG TERM... SAME PROBLEMS REMAIN AS A SERIES OF DISTURBANCES LIFT INTO THE AREA OVER THE NEXT FEW DAYS. THIS WILL LEAD TO PERIODS OF RAINFALL...AND EVEN A CHANCE AT FREEZING RAIN TUESDAY EVENING IF TIMING OF THAT WAVE MATCHES UP WITH EVENING TEMPERATURES OF 30 OR SO. THE WINDOW FOR THIS WILL BE RELATIVELY BRIEF AS TEMPERATURES SLOWLY BUT STEADILY CLIMB THROUGH THE NIGHT...AND ON INTO EARLY THURSDAY MORNING FOR THAT MATTER. THE CONSENSUS ON THE PRECIPITATION EVENT ON TUESDAY NIGHT ACTUALLY DOES SUGGEST MOST OF THE QPF AFTER MIDNIGHT ONCE SURFACE TEMPERATURES ARE BASICALLY ABOVE FREEZING. HOWEVER...THIS WILL BE A CLOSE CALL. WILL BREAK OUT THE NIGHTTIME PERIOD FOR EVENING FREEZING RAIN MENTION NORTHERN 2/3 OF CWA...AND CONTINUE WITH RAIN OVERNIGHT. LIKELY POPS SEEM QUITE REASONABLE AT THIS TIME...AND WILL CARRY 60-70 POPS FOR THE PERIOD. SAME STORY FOR WEDNESDAY WITH RAIN...BY AND LARGE...LIKELY. ATTM... IT APPEARS THAT "EVENT" NUMBER ONE TUESDAY NIGHT WOULD LINGER INTO EARLY WED MORNING...WITH A RELATIVELY CALM DAYTIME PERIOD...FOLLOWED BY INCREASING RAIN COVERAGE LATE IN THE DAY INTO THE EVENING. WILL NOT GET CUTE THOUGH...AS TIMING IN SUCH A SITUATION SEEMS FUTILE. BIGGEST CHALLENGE REMAINS IN THE WEDNESDAY NIGHT AND THURSDAY TIME. HERE...SOUTHERN STREAM STORM LIFTS NORTHEAST ALONG LEADING EDGE OF EXPANDING ARCTIC TROF TO OUR WEST/NORTHWEST. THE RESULTANT SURFACE LOW DEEPENS RAPIDLY AS IT LIFTS ALONG ARCTIC COLD FRONT AS IT SURGES THROUGH LOWER MICHIGAN. WITH THIS SYSTEM COMES A GOOD SLUG OF RAIN LATE WEDNESDAY NIGHT INTO THURSDAY MORNING...WITH PERHAPS THE TAIL END OF THIS (OR MORE APPROPRIATELY...THE TRAILING AREA OF PRECIP W/ UPPER VORT) TURNING TO SNOW ON THURSDAY. WILL MAINTAIN EARLY MORNING HIGHS AROUND 50 ON THURSDAY...WITH TEMPS DOWN INTO THE TEENS/20S BY EVENING. THIS DRAMATIC TEMPERATURE DROP WILL COME ON VERY GUSTY WEST WINDS THURSDAY ON INTO THE EVENING. WILL UP WINDS A BIT...ALTHOUGH CURRENT FORECAST IS IN PRETTY GOOD SHAPE. WILL HAVE TO WATCH THIS PERIOD OF EVEN STRONGER WINDS THAN ARE FORECAST...WITH THAT STRONG OF A PRESSURE SURGE (+18MB RISES IN THE 6 HOUR PERIOD MIDDAY THURSDAY ON AVERAGE. TEMPERATURES CONTINUE ON DOWN FROM THERE AS ARCTIC AIR BUILDS IN ON THROUGH THE WEEKEND. NOT TOO MANY CHANGES HERE. JUST EDGED THE TEMPERATURES DOWN A BIT MORE FROM FRIDAY INTO SATURDAY...WITH A VERY SLOW MODERATION NEXT WEEK. EVEN SO...ARCTIC AIR REMAINS IN PLACE...SO DO NOT PLAN ON A SIGNIFICANT WARMUP. COLD...CYCLONIC FLOW PERSIST THROUGH THE FORECAST...WHICH WILL KEEP SCATTERED SNOW SHOWER CHANCES IN EVERY DAY. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...WINTER WEATHER ADVISORY...MIZ075-076-082-083...FROM MIDNIGHT TONIGHT THROUGH NOON TUESDAY. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ SF/DEG/SC HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EST MON JAN 10 2005 .DISCUSSION... MAIN FCST CONCERNS ARE SNOW CHANCES/AMOUNTS TUE NIGHT AND PCPN TYPE/COVERAGE WED INTO WED NIGHT. ATTENTION THEN SHIFTS TO COLD WAVE FOR LATE THU THROUGH THE WEEKEND. WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL PATTERN ACRS THE NRN CONUS ATOP A RDG ACRS THE SE. TROFFING REMAINS OVER THE WEST WITH POTENT SHRTWV/VORT STILL LURKING OFF THE NRN CA COAST. AT THE SFC...NW FLOW LINGERED BTWN LO PRES OVER NRN QUEBEC AND A RDG FROM NRN MN TO OH. RADAR INDICATED MULTIPLE WIND PARALLEL LES BANDS ALIGNED WITH 300 FLOW GRADUALLY WEAKENING AND SHIFTING TO THE EAST AS WINDS BACK MORE WRLY. TONIGHT...ONSHORE WIND COMPONENT REMAINS OVER THE NRN KEWEENAW AND THE NE CWA THROUGH THE EVENING TIL SFC-H8 RDG BUILD INTO THE AREA BUT THEN END QUICKLY AS THE WINDS BACK. AFTER LES FADES...ATTENTION TURNS TO BAND OF -SN PROGGED TO BRUSH SRN UPR MI. MODERATE TO STRONG 700-600 FRONTOGENESIS WILL BRING SOME SNOW TO THE SOUTH SUPPORTED BY RIGHT ENTRANCE OF H3 JET. HOWEVER...ONLY S MNM COUNTY WOULD BE AFFECTED AND ONLY CHANCE POPS INCLUDED AS ETA/GFS MEASURABLE PCPN LINE REMAINS NEAR THE BORDER. TUE...THE ETA DEPICTS BAND OF WEAK TO MODERATE 700-600 MB FRONTOGENESIS ASSOCIATED WITH RIGHT ENTRANCE OF ANOTHER NRN H3 JET OVER NRN ONTARIO...SINCE THE FORCING IS ONLY MARINGAL AND THE ETA HAS NOT DISPLAYED ONLY -SN OR FLURRIES MENTIONED OVER THE E 2/3 OF THE CWA. TUE NIGHT...A SHRTWV MOVING OUT OF THE PLAINS IN CONJUNCTION WITH UPR LVL DIV IN RIGHT ENTRANCE OF YET ANOTHER H3 JET STREAK WILL SUPPORT LIKELY POPS ACRS UPR MI. DECENT 295K ISENTROPIC LIFT WITH 3-4 G/KG AVBL AND 4-6 HR PERIOD OF SNOW WOULD SUPPORT SNOW AMOUNTS AROUND 3 INCHES. THIS IS ALSO CONSISTENT WITH ETA/GFS QPF NEAR 0.25 INCHES AND SNOW/WATER RATIO NEAR 15/1. ETA PROG OF STRONG FRONTOGENESIS BAND AND STRONG OMEGA IN -12C TO -17C LYR MAY BRING LCLY HIGHER AMOUNTS AOA 5 INCHES IF THE 12Z ETA VERIFIES. ENOUGH UNCERTAINTY REMAINS WHERE AND IF MODERATE TO HEAVY SNOW WOULD DEVELOP SO THAT MORE MODERATE POPS/AMOUNTS MENTIONED AT THIS TIME. WED INTO WED NIGHT...MDLS REMAIN DIVIDED WITH THE OVERALL SCENARIO AS THE GFS DEPICTS EARLIER/STRONGER PHASING OF THE NRN/SRN STREAMS WHILE THE ETA/CANADIAN/UKMET EITHER DELAY OR DO NOT MERGE SRN STREAM ENERGY INTO THE TROF. AS A RESULT THE GFS (AND ENSEMBLE MEAN) IS MORE AGGRESSIVE WITH PUSH OF WARMER AIR AND PCPN INTO UPR MI WITH THE 1305M 1000-850 LINE AND 0C H8 ISOTHERM TO NEAR IRON RIVER TO BIG BAY LINE BY 00Z/THU. THE GFS ENSEMBLE ALSO SHOWS SIGNIFICANT SPREAD WITH REGARD TO TEMP PRFL THROUGH CNTRL UPR MI. THE UKMET/ETA WITH A FLATTER LESS AMPLIFIED NRN STREAM TROF KEEP THERMAL PROFILES COLD ENOUGH FOR MAINLY SNOW EXCEPT FOR ALONG LAKE MI. THE CMC/ETA/UKMET SCENARIO WOULD ALSO BRING SIGNIFICANTLY LESS PCPN INTO UPR MI WITH MAINLY A RAIN BAND DEVELOPING TO THE SE. AT THIS POINT FCST LEANED TOWARD A COMPROMISE BTWN THE ETA/UKMET AND THE GFS. WITH SIGNIFICANT UNCERTAINTY REMAINING...LITTLE CHANGE WAS MADE TO THE GOING FCST WHICH INCLUDES ONLY CHANCE POPS FOR RAIN/SNOW OVER THE CNTRL PORTION (RAIN FAR SE) BY LATE AFTERNOON AND EVENING CHANGING OVER TO SNOW OVERNIGHT. THU...VERY STRONG CAA WILL BRING FALLING TEMPERATURES AS THE ARCTIC AIR POURS IN. WRLY GALES WILL DEVELOP OVER THE LAKE AND SHSN WILL INTENSIFY OVER NW UPR MI WITH CONSIDERABLE BLOWING AND DRIFTING SNOW. CYCLONIC WRLY FLOW WILL ALSO KEEP BETTER LES ALONG THE SHORE NE OF MUNISING. OTHERWISE...SCT -SHSN OR FLURRIES. FRI-MON...MDLS ARE CONSISTENT IN BRINGING VERY COLD AIR INTO THE GRT LAKES WITH H8 TEMPS TO AT LEAST -25 TO -30C (PER THE ECMWF) OR EVEN -30 TO -35C (PER GFS BY 12Z SAT). THE UKMET DEPICTS A SLIGHTLY LESS AMPLIFIED PATTERN WITH DEEPEST COLD AIR REMAINING FARTHER NORTH. EVEN WITH HEDGE TOWARD ECMWF...GIVEN TYPICAL GFS COLD BIAS...BRUTAL CONDITIONS EXPECTED WITH WIND CHILLS LIKELY INTO THE ADVY/WARNING CATEGORY FROM FRI INTO SAT. DAYTIME HIGHS WILL ALSO REMAIN BLO 0F OVER MUCH OF UPR MI TIL SUN WHEN SOME MODERATION IS EXPECTED. LES WILL PERSIST THROUGH THE PERIOD FOR LOCATIONS FAVORED BY W TO WNW FLOW ALTHOUGH WEAK CLIPPER SHRTWVS WILL BRING SOME OSCILLATION IN THE WIND PATTERN. WITH SUCH COLD AIR...MICROPHYSICS FOR SNOW GROWTH WILL NOT BE FAVORABLE SNOWFLAKE GROWTH ALTHOUGH IF SOME STRONGER BANDS SET UP...PERIODS OF HIGHER ACCUMULATION RATES MAY BE POSSIBLE. IN GENERAL...EVEN FOR FAVORED LOCATIONS...AMOUNTS SHOULD STAY AT OR BLO 2-4 INCHES/12 HRS. WITH WINDS OFF THE LAKE AT LEAST IN THE 20-30KT RANGE...FREQUENT/PERSISTENT LOW VSBYS EXPECTED THOUGH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 545 AM EST MON JAN 10 2005 .DISCUSSION... FCST CONCERNS INCLUDE LIGHT LES TODAY...CHC OF SNOW AGAIN TUE NIGHT...PTYPE CONCERNS WED AND THEN SEVERE ARCTIC OUTBREAK LAST HALF OF THE WEEK. WATER VAPOR IMAGERY LOOP AND RUC ANALYSIS SHOW POTENT SHORTWAVE FROM LAST NIGHT NOW LIFTING EAST INTO QUEBEC WITH WEAK MID LVL RDG BUILDING IN BEHIND IT OVER THE NRN PLAINS. MID-LVL TROUGH/CLOSED LOW OFF THE PAC NW COAST WILL GET PROPELLED INTO SW STATES BY LATE TUE AS ARCTIC AIR BEGINS TO SURGE SOUTHWARD THROUGH WRN CANADA. TODAY...3.9 MICRON IR SATELLITE IMAGERY SHOWS SOME LES BANDS OVER LAKE SUPERIOR DVLPG IN CAA WNW FLOW BEHIND SYSTEM NOW MOVING INTO QUEBEC. BOTH ETA AND GFS FCST SOUNDINGS INDICATE LOW INVERSION HGTS OF AROUND 3KFT WITH FAIRLY DRY AIR FILTERING IN BLO INVERSION. TEMPS AT BASE OF INVERSION FALL TO AROUND -15C TO -16C THIS MORNING SO EXPECT LES WILL BECOME A BIT MORE DEVELOPED BTWN 12-16Z. WITH LOW INVERSION AND DRY AIR UPSTREAM...BELIEVE ACCUMULATIONS WILL BE LIMITED TO AROUND AN INCH OVER ONT-CMX-KEW COUNTIES AND 1-2" OVER ALGER-LUCE AND NRN SCHOOLCRAFT COUNTIES. REST OF COUNTIES WILL SEE SCT -SHSN OR FLURRIES WILL A DUSTING OF ACCUMULATION. LES WILL WIND DOWN AND END THIS EVENING AS SFC HIGH PRES SLIDES ACROSS UPPER GREAT LAKES AND WINDS BACK TO AN OFFSHORE DIRECTION. WILL KEEP WITH GOING FCST OF LOWS FALLING TO A FEW DEGREES BLO ZERO OVER WRN INTERIOR WITH LIMITED CLOUD COVER ALLOWING FOR DECENT RADIATIONAL COOLING. GENERALLY MODELS SHOW SFC HIGH PRES RIDGE EXTENDING BACK W INTO THE UPPER GREAT LAKES TUE. MODEL CONSENSUS THE SHOWS A WEAK SHORTWAVE AND ASSOCIATED SFC LOW TO TRACK NE INTO THE LWR MI TUE NIGHT SPREADING WAA SNOW INTO CWA AT THAT TIME. INCLUDED LOW CHC POPS FOR SNOW OVER WRN COUNTIES WITH HIGH CHC POPS FOR E AND SE. LATEST MODEL RUNS TRENDING TOWARD A PHASING OF JET STREAM ENERGY AND DEVELOPMENT OF STORM SYSTEM NORTH AND EAST OF LAKE SUPERIOR. THIS SOLN WOULD APPEAR TO KEEP ANY MIXED PCPN CONFINED TO SE OVER ERN COUNTIES OF CWA. FOR NOW KEPT IN RAIN/SNOW MIX WORDING FOR CENTRAL AND ERN COUNTIES WED AFTERNOON INTO WED NIGHT...WITH STRAIGHT SNOW FOR THE WEST. FUTURE SHIFTS MAY NEED TO SCALE BACK MIXED PCPN EVEN FARTHER EAST GIVEN THESE RECENT MODEL TRENDS. ARCTIC AIR AND BITTER COLD TEMPS STILL POISED TO MOVE INTO AREA THU NIGHT INTO SUN. WOULD NOT BE SURPRISED TO SEE ALL TIME RECORD LOW TEMPS CHALLENGED FRI NIGHT AS 06Z GFS SHOWS -30C OR COLDER 850 MB TEMPS OVER REGION AND 1056 MB HIGH SETTLES OVER THE NRN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING E 2/3RDS OF LAKE SUPERIOR. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1000 AM CST MON JAN 10 2005 .DISCUSSION... SOME PRETTY SIG SHORT TERM CHANGES COMING BY 1630Z. WILL BE SIGNIFICANTLY INCREASING POPS ACRS MUCH OF SRN MN INTO THE METRO IN WRN WISC FOR THIS AFTN EVE IN ACCORD WITH NEW 12Z ETA12 AND 12Z RUC. EXPECT A NARROW BAND OF 1-3" OF SNOW. 12Z MDLS SHOWING STRONG ISENTROPIC LIFT IN RIGHT ENTRANCE REGION OF DEPARTING H3 JET. 2-3 G/KG PER 295K WITH 4 G/KG JUST TO OUR SOUTHWEST. WEAK H7 S/W TROF TO MOV OUT OF CNTL PLAINS INTO IA...WITH MID LVL LOW BACKING A BIT PROVIDING BETTER WAA AND LIFT INTO THE DEPARTING MID LVL FRONTAL ZONE DEPARTING UNDR UPR JET. RESULT IS SOME VERY NICE 2D FRONTO FORCING AT H7/H6 LIFTING NORTHEAST ACRS CWA THIS AFTN/EVE. DENDRITIC GROWTH IDEAL AND COLD LLVL AIRMASS SUGGESTS SNOW WL BE FLUFFY AND SIT NICE YIELDING ACCUMULATIONS UNDER HI SNW/WTR EQUIVALENTS. CROSS SECTIONS NORMAL TO THE THICKNESS FIELD OVER SRN MN/WRN WI INDICATES SOME NICE -EPV* IN THE HEART THE LIFTING ZONE WHICH ALSO IS WHERE THE IDEAL DENDRITIC TEMPS EXIST. SO SOME A NARROW BAND OF MORE INTENSE LIFT COULD YIELD A 3" ACCUM. THIS SEEMS LIKELY SRN METRO IN WRN WI THIS EVE. COULD BE A MESSY EVENING RUSH IN METRO. THINK BAND OF SNOW ON MPX 88-D OVR WRN MN/ERN SD WL CONT TO SPREAD EAST WITH MUCH IT GOING INTO SATN THRU EARLY AFTN WITH SCT SW--. BY MID/LATE AFTN...WITH CONTINUED ISENTROPIC ASCENT AND LIFT...SNOW SHOULD INCREASE AS BAND ELONGATES BACK INTO WRN MN. WILL BE UPDATING HWO. TOMORROW LOOKING VERY INTERESTING AS WELL. NOT WHAT WE NEED RIGHT AHEAD OF THE ARCTIC AIR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ BINAU mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 935 AM CST MON JAN 10 2005 FORECAST CHALLENGE CONCERNS CLOUD TRENDS/TEMPERATURES. SURFACE HIGH PRESSURE CENTERED OVER FORECAST AREA TODAY. UPSTREAM SHORT WAVE ENERGY AND ENTRANCE REGION OF UPPER JET PROVIDING AREAS OF CLOUD COVER TODAY. TEMPERATURES OVER NORTHERN THIRD STARTING OUT COLDER THAN EXPECTED. LITTLE HELP FROM RETURN FLOW/WARM ADVECTION AS ONLY SLIGHT MIXING EXPECTED. WILL TAKE A LAST LOOK HOWEVER WILL NEED TO KNOCK DOWN MAX TEMPERATURES A NOTCH CLOSER TO RUC GUIDANCE WHICH SEEMS MORE REASONABLE UNDER THE CIRCUMSTANCES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 915 PM CST MON JAN 10 2005 .DISCUSSION... STRONG FRONT RESUMING SLOW S-WARD DRIFT BUT LATEST TRENDS INDICATE MOVEMENT A LITTLE FASTER THAN MODEL PROGS. WILL USE RUC TO TIME WIND SHIFT AND TEMP BREAK INTO SW OK AND S OF OKC AREA BY LATE TONIGHT. DENSE FOG ADVISORY IS EXTENDED S TO ABOUT I-40 AS VISIBILITY HAS FALLEN TO 1/4MI OR LESS IN PARTS OF OKC AREA. ONLY OTHER VISIBILITY PROBLEMS CURRENTLY ARE IN NW OK...BUT THERE IS ENOUGH VARIABILITY THAT AREAS OF DENSE FOG COULD EXIST MOST ANYWHERE BEHIND THE FRONT. THUS WILL CONTINUE ADVISORY FOR THE REST OF N OK. MAY NEED TO WATCH DEVELOPING -FZDZ IN NW OK - ERRONEOUSLY BEING REPORTED AS SNOW AT WWD - FOR POSSIBLE CHANGE WO WINTER WX ADVY IF ICING ADDS TO TRAVEL PROBLEMS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 39 47 40 52 / 20 20 20 40 HOBART OK 37 50 45 53 / 10 10 20 40 WICHITA FALLS TX 53 66 52 66 / 10 10 20 40 GAGE OK 27 36 32 34 / 20 20 20 30 PONCA CITY OK 29 36 30 43 / 20 20 20 40 DURANT OK 59 68 55 71 / 10 10 20 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 24 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 307 PM CST MON JAN 10 2005 .DISCUSSION... FRONT HAS LIFTED NORTH SOMEWHAT TODAY. EXPECT THIS FRONT TO PUSH FURTHER SOUTH TONITE THAN LAST NITE. HOW FAR SOUTH IS STILL UNCERTAIN. HAVE LEANED MORE TO THE ETA12/RUC FRONTAL POSITION SINCE SEEMS TO HAVE BEST HANDLE ON THE FRONT TODAY. FRONT WILL CONT TO WAFFLE ACROSS THE CWA FOR A COUPLE OF DAYS AS UPR LOW MOVES ACROSS WESTERN U.S. MAKING TEMPS A CHALLENGE TO FORECAST...WITH A LARGE RANGE IN TEMPS ACROSS CWA. FOG/-DZ EXPECTED BEHIND THE FRONT TONITE... WITH -FZDZ POSSIBLE ACROSS NORTHERN OK. DENSE FOG WILL CONT TO AFFECT PARTS OF NORTHERN OK THIS EVENING. WILL ISSUE DENSE FOG ADVSY FOR NORTHERN 2 TIERS OF COUNTIES. MAY NEED TO EXTEND SOUTHWARD BUT WITH UNCERTAINTY OF FRONTAL POSITION WILL LET EVENING SHIFT MONITOR. BEST CHANCE FOR DENSE FOG LATER TONITE MAY BE NEAR THE FRONT WHERE COOLER AIR MOVES INTO MOIST AIR THAT IS CURRENTLY SOUTH OF FRONT. UPR LOW FINALLY MOVES ACROSS THE PLAINS BY MID WEEK. TIMING AND POSITION OF THIS SYSTEM IS STILL UNCERTAIN WITH THE ETA SLOWER AND FURTHER SOUTH THAN THE GFS. HOWEVER...SHWRS AND SOME TSTMS ARE POSSIBLE TUES NITE THRU WED NITE. FZRA COULD ALSO OCCUR ACROSS NORTHERN OK TUES NITE/WED...EVENTUALLY CHANGING TO SN BEFORE ENDING WED NITE. BELIEVE MAJORITY OF PRECIP WILL STAY LIQUID FOR MOST OF THE AREA WITH A BRIEF CHANGE TO FZRA/SN IN SOME LOCATIONS BEFORE ENDING AS SYSTEM MOVES EAST AND DRY AIR MOVES IN. COLD FRONT WILL MOVE ACROSS THE FA LATE WED/WED NITE WITH ANOTHER FRONT MOVING INTO THE FA THURS BRINGING ARCTIC AIR TO THE FA THAT WILL AFFECT THE AREA INTO THE WEEKEND. WITH ARCTIC AIR DIFFICULT TO ERODE AND THE BIAS IN MODELS TO GET RID OF THIS TYPE OF AIRMASS QUICKER THAN USUAL...HAVE GONE BELOW GUIDANCE THRU THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 40 47 40 52 / 20 20 20 40 HOBART OK 41 50 45 53 / 10 10 20 40 WICHITA FALLS TX 52 66 52 66 / 10 10 20 40 GAGE OK 30 36 32 34 / 20 20 20 30 PONCA CITY OK 30 36 30 43 / 20 20 20 40 DURANT OK 58 68 55 71 / 10 10 20 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...DENSE FOG ADVISORY TONIGHT OKZ004>013. TX...NONE. && $$ 25 ok AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 941 AM EST MON JAN 10 2005 .SHORT TERM (REST OF TODAY)... FOG IS DISSIPATING ACROSS THE AREA AND ADVISORY WILL BE ALLOWED TO EXPIRE AT 10 AM. RIDGE ALOFT AND AT SFC WILL CONTINUE TO BE DOMINANT FEATURE TODAY. MAY TWEAK HOURLY TEMPS BUT FORECAST HIGHS LOOK GOOD. WILL UPDATE MAINLY TO REMOVE MENTION OF FOG AND CLEAN UP WORDING. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 346 AM EST MON JAN 10 2005 SHORT TERM (REST OF TODAY)... LATEST RUC AND ETA SOUNDINGS AGREE ON LOW CLOUDS AND DENSE FOG DEVELOPING INTO CLT METRO AREA AND PERSISTING UNTIL 15Z. WILL ISSUE DENSE FOG ADVISORY FROM CONCORD TO GASTONIA TO CHESTER THROUGH 10 AM. THE FOLLOWING WAS ORIGINALLY ISSUED AT 205 AM EST MON JAN 10 2005 SHORT TERM (TODAY THROUGH WEDNESDAY)... IR SATELLITE IMAGERY AND SFC OBSERVATIONS DEPICT AN AREA OF LOW CLOUDS AND DENSE FOG MOVING WESTWARD FROM THE COAST INTO THE PIEDMONT OF THE CAROLINAS. SUBSTANTIALLY REDUCED VISIBILITIES COULD PENETRATE INLAND CLOSE TO THE CLT METRO AREA BY DAYBREAK. THIS WILL HAVE TO BE MONITORED CLOSELY FOR A POSSIBLE DENSE FOG ADVISORY...BUT CURRENT INDICATIONS ARE THAT FOG DECK SHOULD STAY JUST TO THE SOUTHEAST. STRATOCUMULUS IS ALSO ADVANCING QUICKLY EASTWARD THROUGH TN THIS MORNING AHEAD OF A COLD FRONT STRETCHING FROM THE GREAT LAKES TO THE MID MS RIVER VALLEY. MODEL TIME HEIGHTS INDICATE THAT MUCH OF THIS LOW LEVEL MOISTURE SHOULD DRY UP AS IT HITS THE SPINE OF THE APPALACHIANS EARLY TODAY...LEAVING MAINLY HIGH CLOUDINESS IN THE SWIFT ZONAL FLOW FOR THE BULK OF THE SKY COVER. AFORE MENTIONED FRONT SHOULD LAY OVER JUST NORTH OF THE FORECAST AREA TONIGHT...BEFORE RETURNING NORTHWARD AS A WARM FRONT ON TUESDAY. MOIST UPGLIDE OVER THIS BOUNDARY IS EXPECTED TO BE CONFINED MAINLY TO THE OHIO RIVER VALLEY TUESDAY...BUT SCATTERED SHOWERS WILL BE POSSIBLE ACROSS THE WRN APPALACHIANS BY TUE AFTN. RETURN FLOW WILL SET UP IN EARNEST WED...WITH A STRENGTHENING ATLANTIC RIDGE JUST OFFSHORE...AND A DEEPENING LOW PRESSURE SYSTEM MOVING INTO THE PLAINS. ANY PRECIP CHANCES WILL BE DIURNALLY DRIVEN AND CONFINED MAINLY TO THE HIGHER MTN ELEVATIONS ON WEDNESDAY. TEMPERATURES WILL CONTINUE TO RUN WELL ABOVE NORMAL THROUGH MID WEEK. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)... SHARP FRONT SHOULD TRANSITION RAPIDLY EASTWARD TOWARD THE SRN APPALACHIANS ON THURSDAY AS THE ASSOCIATED SFC LOW CENTER MOVES ACROSS THE GREAT LAKES. GFS CONTINUES TO FEATURE A FASTER FROPA THAN ADVERTISED ON MEDIUM RANGE CONSENSUS YESTERDAY. THIS WILL PUSH UP CONFIDENCE FOR PRECIPITATION THU IN THE MTNS AND THU NIGHT IN THE PIEDMONT...ALLOWING FOR LIKELY RAIN CHANCES. WILL CONTINUE CHC PRECIP MENTION INTO FRIDAY AND KEEP MTN PTYPE LIQUID GIVEN GFS TENDENCY TO COOL THINGS DOWN TOO QUICKLY. AVIATION... FOG PRODUCT IR IMAGERY SHOWS FOG/STRATUS ACRS THE SC COASTAL PLAIN AND EXPANDING NWWD. ETA BLYR RH PROGS SEEM TO HAVE A GOOD HANDLE ON CURRENT DEVELOPMENT AND SPREADS HI RH VALUES INTO THE CLT METRO BY DAYBREAK. 00Z ETA BUFKIT SOUNDINGS INDICATING VERY FAVORABLE LLVL PROFILE FOR LIFR FOG AND/OR STRATUS DURING THE PRE-DAWN HOURS. IT IS ALSO INTERESTING TO NOTE THAT NONE OF THE NUMERICAL GUIDANCE IS INDICATING ANY TYPE OF FOG AT KCLT THIS MORNING...EVEN THE MET. WILL FEATURE SOME MEASURE OF IFR FOG DEVELOPMENT AT CLT FOR THE PREDAWN. AT KAVL...THE 00Z TREND FOR THE PRE-DAWN HAS BEEN DRIER WITH MORE LLVL MIXING AND NW SFC WIND. 00Z NUMERICAL GUIDANCE ACRS THE BOARD BAILS OUT ON ANY LATE NIGHT FOG WITH PREVIOUSLY HARD HITTING FWC/MAV NOW P6SM ALL NIGHT. LARGE AREA OF MVFR CIGS ACROSS WRN AND CNTL TN ADVANCING EASTWARD FASTER THAN M-ETA HAS PROGD. MAY HAVE SCT CLOUDS ENCROACHING ON KAND AND KGSP EARLY THIS MORNING. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...RB sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 907 PM CST MON JAN 10 2005 .DISCUSSION... AREA OF MIXED PRECIP MOVING PRETTY MUCH STRAIGHT EAST ACROSS NORTHERN NEBRASKA THIS EVENING...AND COULD BRUSH SUX AREA IN 05Z-09Z TIMEFRAME. HAVE BEEN SOME REPORTS OF -FZRA WITH THIS PRECIP...BUT MAY IN SOUTHERN PORTION WITH KANW HAVING REPORTED --SN AS THE ECHOES PASSED OVER THAT SITE A COUPLE HOURS AGO. 00Z KOAX RAOB LOOKS GOOD FOR -FZRA POTENTIAL SOUTH OF OUR CWA...WITH WARM LAYER REACHING +5C. HOWEVER LAPS AND RUC SOUNDINGS FOR KSUX HAVE WARM LAYER ONLY TOPPING OUT AT +1C...WITH SUBFREEZING LAYER BENEATH THIS A LITTLE OVER 3KFT DEEP AND COOLING TO AS MUCH AS -10C. THUS WOULD THINK IF ANY PRECIP MAKES IT INTO FAR SOUTHERN CWA OVERNIGHT...IT WOULD BE -SN OR -PL RATHER THAN -FZRA. HAVE ADDED A LOW CHANCE POP FOR THIS TO FAR SOUTHERN COUNTIES THROUGH 09Z...BUT BULK OF MEASURABLE PRECIP SHOULD REMAIN SOUTH OF THE CWA...ALTHOUGH 00Z ETA QPF OF 0.10 TO 0.25 SEEMS A LITTLE OVERDONE. AFTER THIS MOVES THROUGH...SOUNDINGS STILL SUPPORT SMALL CHANCE OF -FZDZ AS LOW STRATUS EXPANDS INTO THE AREA. THINK OVERNIGHT LOWS MAY BE A LITTLE TOO COOL GIVEN EXTENSIVE CLOUD COVER...BUT HOURLY TEMPS HAVE BEEN VERIFYING FAIRLY WELL...AND STILL QUITE A BIT OF NIGHT LEFT SO WILL LEAVE LOW TEMPS ALONE FOR NOW. QUICK GLANCE AT 00Z ETA CONTINUES TO SUPPORT GOING FORECAST OF HIGHEST POPS ACROSS FAR NORTHERN CWA WITH LOWEST IN THE FAR SOUTH... ALTHOUGH TIMING A LITTLE SLOWER THAN GOING FORECAST WITH ETA NOT GIVING MOST AREAS MUCH OF ANY PRECIP UNTIL AFTERNOON. WITH ETA FORECAST OF UPPER WAVE AND MID LEVEL FRONTOGENESIS FOCUSED IN FAR NORTHERN CWA OR EVEN FARTHER NORTH...SRN AREAS MAY NOT SEE MUCH MORE THAN AFOREMENTIONED CHANCE OF -FZDZ. WILL NOT MAKE ANY CHANGES AT THIS TIME GIVEN ONLY ONE MODEL SOLUTION...BUT IF 00Z GFS SUPPORTS ETA SOLUTION...MID SHIFT MAY HAVE TO DROP POPS DOWN ACROSS THE SOUTH AND SLOW DOWN ONSET OF PRECIP A FEW HOURS. UPDATED GRIDS FOR TONIGHT HAVE BEEN SENT...AND WILL HAVE UPDATED ZFP OUT SOON. && .AVIATION... MVFR CIGS EXPECTED TO EXPAND SLOWLY NORTHWARD ACROSS THE AREA AFTER 06Z-08Z TIMEFRAME...WITH AREAS OF MVFR VSBYS IN -SN OR -FZDZ/BR ALSO POSSIBLE IN KSUX AND KFSD AREAS AFT 09Z. MVFR-OCNL IFR CIGS/VSBYS IN -SN EXPECTED TO SPREAD ACROSS MAINLY KHON/KFSD AREAS AFT 15Z...AS UPPER LEVEL WAVE SLIDES JUST NORTH OF KHON. SMALLER CHANCE OF -SN IN KSUX...ALTHOUGH IFR CIGS/VSBYS STILL LIKELY WITH -FZDZ POSSIBLE THROUGH 00Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ HACKER sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 846 PM CST MON JAN 10 2005 .UPDATE...LATEST RADAR AND SURFACE OBSERVATIONS INDICATED BAND OF SNOW EXTENDED FROM NEAR KMSP THROUGH THE KEAU AREA...THEN INTO EAST CENTRAL WI. THIS WAS ASSOCIATED WITH MID LEVEL FRONTOGENETIC FORCING AS SEEN IN RUC AND ETA. BAND OF SNOW ACTUALLY ESTABLISHED ITSELF A BIT FURTHER NORTH THAN 18Z ETA HAD INDICATED. RUC AND ETA SUPPORT FORCING TO GRADUALLY MOVE EASTWARD TONIGHT. FURTHER SOUTH...FREEZING RAIN AND SNOW ASSOCIATED WITH SURFACE LOW MOVING ACROSS MISSOURI EXPECTED TO REMAIN SOUTH OF OUR SOUTHWEST WI AND ADJACENT ZONES OF NORTHEAST IOWA. OVER REMAINDER OF FORECAST AREA...APPEARS NO PRECIPITATION DURING THE OVERNIGHT WITH FORCING EITHER EXITING OR REMAINING SOUTH OF THE AREA. UPDATED ZONES WERE ISSUED AT 0232Z AND LATEST TRENDS ALSO REFLECTED IN DATA BASE. && THOMPSON .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT VERY CHALLENGING FORECAST THIS SET WITH MULTIPLE PRECIPITATION CHANCES AND PRECIPITATION TYPE ISSUES TO SORT OUT...DUE MAINLY TO INFLUENCE OF BOTH SOUTHERN AND NORTHERN STREAM WEATHER SYSTEMS THROUGH MID-WEEK. ACTIVE PATTERN WILL TRANSITION INTO QUIETER BUT MUCH...MUCH COLDER WEATHER BY END OF WEEK. UPPER FLOW NEARLY ZONAL THIS AFTERNOON WITH STRONG UPPER JET EXITING GREAT LAKES REGION. MAIN LOWER LEVEL BAROCLINIC ZONE REMAINS TO THE SOUTH...FROM NORTHERN ILLINOIS INTO KANSAS WITH WEAK SURFACE RIDGE ACROSS NORTHERN MINNESOTA AT 19Z. COMBINATION OF WEAK SHORT WAVE TROUGH PASSING BY TO THE NORTH AND LIFT GENERATED FROM RIGHT EXIT REGION OF UPPER LEVEL JET IS PRODUCING BANDS OF SNOW FROM EASTERN SOUTH DAKOTA INTO CENTRAL MINNESOTA. THIS AREA OF RELATIVELY WEAK FORCING EXPECTED TO TRACK EAST AND SHOULD ENHANCE COVERAGE AREA OF DEVELOPING SNOW THIS EVENING...ESPECIALLY NORTH OF INTERSTATE 90. THIS IS FARTHER NORTH THAN EARLIER EXPECTED SO HAVE SHIFTED POPS AND SNOWFALL AMOUNTS ACCORDINGLY. FORCING SHOULD CONTINUE TO SATURATE LAYERS AND MINIMIZE FREEZING DRIZZLE THREAT IN SOUTHERN FORECAST AREAS. VARIOUS PRECIPITATION TYPE SCHEMES SUGGEST JUST SNOW THROUGH 12Z TUESDAY. TUESDAY NIGHT BRINGS ANOTHER PRECIPITATION CHALLENGE AS ANOTHER SHORT WAVE TROUGH IN NORTHERN FLOW AFFECTS THE GREAT LAKES. Q-G CONVERGENCE IS FAIRLY DEEP AS THIS ENERGY MOVES THROUGH...BUT NOT VERY STRONG. BEST FORCING MOVES JUST NORTHWEST OF FORECAST AREA FOR ANOTHER ROUND OF LIGHT SNOW. NOT MUCH TO FOCUS ON ELSEWHERE EXCEPT AS HIGHER LEVEL CLOUDS...ICE SOURCE...MOVE AWAY FROM PASSING SHORT WAVE TROUGH...AND WARMING IN LOWER LEVELS CONTINUE...MAY SEE MORE PATCHY FREEZING DRIZZLE WITH LOCKED STRATUS LAYER. DIFFERENCES ABOUND IN SHORT TERM MODELS WITH HANDLING OF STRONG SHORT WAVE TROUGH EJECTING OUT OF SOUTHWEST FLOW BY MID-WEEK. 12Z GFS CONTINUES TO BE STRONGER AND FASTER THAN ETA. COMPROMISE PROBABLY IN ORDER BASED ON PERFORMANCE WITH EJECTING SOUTHWEST SYSTEMS SO FAR THIS SEASON. IN ANY EVENT...MUCH STRONGER FORCING EXPECTED WITH THIS AS IT MOVES INTO MISSISSIPPI RIVER VALLEY BY LATE WEDNESDAY. ASSUMING SURFACE LOW REMAINS JUST SOUTHEAST OF FORECAST AREA...BULK OF HEAVIER PRECIPITATION WILL REMAIN IN FAR SOUTHERN COUNTIES OR SOUTHEAST OF FORECAST AREA. LOW LEVELS LIKELY WARM ENOUGH FOR JUST RAIN IN THAT AREA BUT WILL BEAR WATCHING. MIX OF PRECIPITATION POSSIBLE NORTHWEST OF THERE...WITH SNOW LIKELY SETTING UP ACROSS SOUTHERN MINNESOTA INTO NORTHWEST WISCONSIN BY WEDNESDAY EVENING. IN FACT...GOOD MID-LEVEL FRONTOGENETICAL FORCING IN THIS AREA COULD SETUP SNOW BAND AND THEN ADVANCE IT SOUTHEAST WITH SYSTEM BY THURSDAY MORNING. BIG STORY AFTER THAT IS FALLING TEMPERATURES. STRONG COLD AIR ADVECTION WILL KICK IN EARLY THURSDAY WITH TEMPERATURES LIKELY FALLING ALL DAY. PRECIPITATION WILL CUT OFF EARLY ON THURSDAY AS SUBSIDENCE TAKES OVER. .LONG TERM...FRIDAY THROUGH MONDAY LARGE LONG WAVE TROUGH SETS UP IN LONGER TERM WITH VERY COLD AIR IN PLACE FOR FIRST SEVERAL DAYS. FRESH SNOW COVER IN SOME PLACES MAY PRODUCE EVEN COLDER READINGS. LARGE SCALE CYCLONIC FLOW WITH EMBEDED SHORT WAVE TROUGH MAY PRODUCE ENOUGH LIFT FOR A FEW FLURRIES ON FRIDAY BUT BIG NEWS WILL BE TEMPERATURES. SOME MODERATION POSSIBLE BY LATE IN THE WEEKEND AS TROUGH AXIS SHIFTS EAST. && .ARX WATCHES/WARNINGS/ADVISORIES... .WI...NONE. .MN...NONE. .IA...NONE. && $$ SHEA wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 345 AM EST TUE JAN 11 2005 ...DENSE FOG ADVISORY FOR SOUTHERN FL ZONES UNTIL 9 AM... .CURRENTLY...WIDESPREAD DENSE FOG HAS DEVELOPED ACROSS SOUTHERN AND COASTAL PORTIONS OF OUR FORECAST AREA THIS MORNING...AND CONDITIONS WARRANTED THE ISSUANCE OF A DENSE FOG ADVISORY FOR ALACHUA...MARION AND PUTNAM COUNTIES AROUND 1AM. WE MAY NEED TO INCLUDE FLAGLER COUNTY IN THE ADVISORY AROUND ZFP ISSUANCE TIME. HIGH CLOUDS BLANKET MUCH OF OUR GA ZONES AND N FL ZONES WHERE LITTLE FOG IS REPORTED...AND BELIEVE THAT INCREASING HIGH CLOUDINESS THROUGH DAWN SHOULD BEGIN TO IMPROVE CURRENT LOW VISIBILITIES ACROSS MOST OF OUR ZONES. THE RUC40 1000-500MB MEAN LAYER FLOW INDICATES THE MEAN RIDGE HAS SHIFTED OFFSHORE OF THE FL PENINSULA WITH AN AXIS THROUGH CENTRAL FL. A SHORT WAVE TROUGH OVER TX IS ADVANCING EAST AND INCREASING HIGH CLOUDINESS OVER THE LOCAL AREA. TEMPS AND DEW PTS ARE IN THE MID 50S ACROSS THE AREA THIS HOUR...WITH DEW PT DEPRESSIONS ONLY 1-2 DEG. .SHORT TERM...FOG AND LOW CIGS ARE EXPECTED TO BE SHORT LIVED FOLLOWING DAY BREAK AS HIGH CLOUDS WILL COVER MUCH OF THE AREA AND SSW BOUNDARY LAYER WINDS INCREASE. ONCE THE LOW CIGS CLEAR...HIGH CLOUDS AND SCATTERED AFTN CUMULUS WILL MAKE FOR PARTLY CLOUDY SKIES ACROSS THE AREA. TEMPS WILL ONCE AGAIN WARM INTO THE LOW-MID 70S AS UPPER LVL FLOW REMAINS WSW KEEPING THICKNESS HIGH OVER THE SOUTHEAST REGION. USED A MOS BLEND FOR TEMPS LEANING MORE TOWARD THE COOLER MAV MOS FOR MAXES DUE TO HIGH CLOUDS OVER THE AREA. TONIGHT EXPECT ANOTHER ROUND OF FOG...BUT INCREASING LOW LVL WINDS AND HIGH CLOUDS ARE EXPECTED TO PRECLUDE A WIDESPREAD DENSE FOG EVENT. MINS WILL BE SLIGHTLY WARMER THAN THIS MORNING DUE TO INCREASED MIXING AND CLOUD COVER. WED AND WED NIGHT...WARM SLY FLOW SETS UP ACROSS THE AREA AS A LONG WAVE TROUGH DIVES OVER THE PLAINS AND SHUNTS THE ATLANTIC RIDGE FURTHER EAST WHILE AMPLIFYING ITS AXIS ALOFT. WARM AIR ADVECTION WILL BE IN FULL FORCE LATE WED DESPITE CLOUD COVER WITH MAX TEMPS IN THE MID TO UPR 70S AND MINS WARMING INTO THE MID 50S TO LWR 60S. BOTH THE GFS AND ETA CONTINUE TO ADVERTISE A PRE-FRONTAL PIECE OF POSITIVE VORTICITY AND SURGE OF ATLANTIC MOISTURE ROTATING OVER THE FL PENINSULA WED NIGHT INTO EARLY THU...AND BASED ON MODEL CONSISTENCY WILL CONTINUE TO ADVERTISE A 20% OF SHOWERS MAINLY AFTER MIDNIGHT. THU...THE COLD FRONT MOVES INTO THE SOUTHEAST REGION AND NEARS OUR WESTERN GA ZONES THU EVENING. PRE-FRONTAL ENERGY AND MOISTURE WILL BRING A GOOD CHANCE OF SHOWERS AND ISOLD TSTORMS TO THE LOCAL FORECAST AREA WITH HIGHER CHANCES NEAR THE COAST IN THE MORNING... THEN INCREASING CHANCES OF PRECIP DURING THE AFTERNOON INLAND AS THE FRONT APPROACHES. EXPECT ANOTHER DAY OF UNSEASONABLY WARM TEMPS AND BREEZY CONDITIONS WITH 850 MB WINDS 25-30 KTS MIXING DOWN TO THE SFC. .LONG TERM...BOTH THE DGEX AND GFS SHOW A SLOW PROGRESSION OF THE COLD FRONT THROUGH OUR AREA FRIDAY IN RESPONSE TO A DEVELOPING WAVE ALONG THE BOUNDARY SOMEWHERE OVER THE FL PENINSULA. A VERY STRONG 1040MB HIGH BRIDGES THE FRONT FRI-SAT AS THE BOUNDARY BECOMES QUASI- STATIONARY OVER SOUTH FL. THE TIGHT GRADIENT BETWEEN THE HIGH AND THE FRONT IS EXPECTED TO BRING LOCAL NORTHEASTER TYPE CONDITIONS TO A GOOD PORTION OF OUR FL ZONES SAT. DECIDED TO INCLUDE PARTLY CLOUDY CONDITIONS AND A LOW CHANCE OF PRECIP OVER OUR SOUTHERN FL ZONES WITH ENSEMBLE...MEX GUIDANCE...AND GRIDDED FIELDS HOLDING ONTO INGREDIENTS FOR AN OVER-RUNNING EVENT. MEANWHILE OVER OUR GA ZONES THE FIRST FREEZE OF THE YEAR IS POSSIBLE INLAND WHERE TEMPS ARE EXPECTED TO PLUMMET INTO THE 50S SAT AND 20S SAT NIGHT. THE HIGH TO THE NORTH WILL SLOWLY SHIFT SOUTH THROUGH NEXT TUESDAY WHILE MEAN LAYER TROUGHING IS EXPECTED TO PERSIST OVER THE EASTERN CONUS KEEPING TEMPS BELOW CLIMO VALUES. && .MARINE...SOUTH WINDS WILL INCREASE TO SCEC CONDITIONS BY WED NIGHT AS FRONT INCHES CLOSER TO THE AREA. POST FRONTAL WINDS WILL BE EVEN STRONGER WITH NORTH WINDS INCREASING TO 25 KT LATE FRIDAY THEN BECOME NE 25 TO 30 KT ON SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... AMG 73 52 77 56 / 00 10 10 10 SSI 71 56 73 59 / 00 10 10 20 JAX 76 55 77 60 / 00 10 10 20 SGJ 74 59 75 63 / 00 10 10 20 GNV 78 53 79 59 / 00 10 10 20 OCF 78 55 79 59 / 00 10 10 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY THROUGH 9 AM FLZ036-037-040. GA...NONE. && $$ PUBLIC...ENYEDI MARINE/FIRE WX...TRABERT fl AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE CHICAGO IL 315 AM CST TUE JAN 11 2005 .DISCUSSION WILL BE EXTENDING THE END TIME FOR THE CURRENT ADVISORY TO END AT 18 UTC. ONLY NWP CLOSEST TO CURRENT SFC/88D TRENDS IS THE RUC20 AS THE ETA IS TOO COLD AT THE SFC THRU H925. AN INVERTED SFC TROUGH ACROSS THE CWA, CLEARLY RESOLVED BY THE NRN IL/IN MESONET STATIONS, HAS PLAYED HAVOC WITH THE SFC TEMPS AND AS A RESULT PRECIP TYPES/DURATION. THE TROUGH HAS SLIPPED SOUTH AND EAST OVER THE PAST 8 HRS INHIBITING SFC TEMP WARM UP. NORTH OF THE TROUGH AND APPARENTLY ALONG THE H85 STRENGTHENING BAROLCINIC AND CONFLUENCE ZONE, A PERSISTENT MESOBAND OF SN CONTINUES THIS MORNING FOR LOCATIONS NORTH OF I88. THUS FAR UNDER THAT BAND 5 INCHES OF NEW SNOW HAS BEEN REPORTED NEAR GURNEE, 4 AT LAKE VILLA AND 3.5 INCHES 7-8 MILES WNW OF RFD. IT APPEARS THE THAT BAND WILL HOLD TOGETHER BETWEEN RFD TO UGN FOR ANOTHER FEW HRS. WOULD NOT BE SURPRISED TO SEE LOCALIZED 6/7" AMOUNTS BASED ON THE AFOREMENTION REPORTS. WILL NOT BE ISSUING A WARNING GIVEN THE ISOLATED NATURE RESIDING WITHIN THE CURRENT WINTER WEATHER ADVISORY. THE BULK OF THE STEADIER/HEAVIER PRECIP IS NOW EXPECTED TO TAPER OFF NEAR SUNRISE...WITH SCATTERED PRECIP CONTINUING THRU THE DAY WITH PATCHY/AREAS OF FG/BR. TEMPS SHOULD SLOWLY WARM BUT HAVE HELD MIXED WORDING ACROSS THE FAR NW COUNTIES THROUGH THE DAY AS THAT AREA WILL TAKE THE LONGEST TO WARM ABOUT 32F. FROM THERE...HAVE FOLLOWED THE ETA FROM TONIGHT THRU THR MORNING AS THE LATEST GFS APPEARS TOO FAR NORTH WITH ITS SFC FEATURES VS. THE POSITION OF THE LOW-MIDLVL BAROCLINIC ZONE. TONIGHT NW IN STANDS TO RECEIVE THE LARGEST PRECIP AMOUNTS AS THE NEXT S/WV PASSES ACROSS THE REGION. HAVE ADDED AREAS OF FG FOR TONIGHT THRU WED NIGHT. WED AFTERNOON INTO WED NIGHT WILL SEE THE ARRIVAL OF THE LAST IN THE RECENT SERIES OF S/WV TROUGHS. MODEL QPFS PRODUCE 3/4 TO 1.5 INCHES OF ADDITIONAL RAINFALL ACROSS THE CWA. WILL HOIST AN AREAL FLOOD WATCH FOR THE ENTIRE CWA VALID 00 UTC THR TO 12 UTC THR AS RUNOFF ATOP THE RESIDUAL SNOW PACK, BLOCKED DRAINS/CULVERTS, AND/OR THE CURRENT HIGH SOIL MOISTURE COULD CAUSE LOW SPOTS TO FILL WITH WATER. SHOULD SEE A CHANGE OVER TO SN LATE WED NIGHT BEHIND A STRONG COLD FRONT. AT THIS TIME ACCUMULATIONS APPEAR LIGHT. -SHSN LINGER INTO THRU MORNING WITH TEMPS FALLING THROUGH THE DAY. LEFT THE COLD EXTEND PERIODS IN TACT THIS GO AROUND. && .AVIATION... ST DECK MOVING INTO TAF AREA ATTM. EXPECT CIGS TO GRADUALLY LOWER THROUGH 06Z. 88D SHOWS PRECIP MOVING INTO SOUTHERN PORTION OF CWA. HIGH DBZ RETURNS SUGGEST PRECIP TYPE IS LQIUID COATED ICE SO MAY SEEN SOME ICE PELLETS AND/OR FREEZING RAIN AT INITIATION. THOUGH CANT CUT THE CHEESE THIS CLOSE...CURRENT THINKING IS THAT MOST LIKELY AREA FOR FREEZING RAIN WILL BE SOUTHERN TAFS WHILE ITS MORE LIKELY TO SEE SNOW AND ICE PELLETS IN NORTHERN TAFS. MAIN PRECIP EVENT IS OVER BY 12Z. SEE NO REASON FOR CIGS/VSBYS TO IMPROVE THROUGH 00Z WITH CROSS SECTIONS SHOWING 90+ RH IN LOWER LAYERS THROUGH WED. && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...WINTER WX ADVSRY UNTIL NOON TUES ROUGHLY N STREATOR-KVPZ LINE. .IN...WINTER WX ADVSRY UNTIL NOON TUES FOR LAKE/PORTER COUNTIES. .LK MI... $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 408 AM EST TUE JAN 11 2005 .SHORT TERM... TODAY AND TONIGHT INITIAL WAVE/I295 CROSS ISALLOBARIC FLOW GENERATING ADVISORY LEVEL PRECIP ACROSS NORTHERN THIRD OF CWA AS FAIRLY FAST MOVING. IN MICHIGAN CURRENTLY BEST LIFT AND DYNAMIC/EVAPORATIVE COOLING WITH 900-700 MB INITIAL DRY LAYER ENOUGH TO KEEP PROFILE COLD ENOUGH FOR SNOW WITH ONE REPORT OF NEAR 2 INCHES ALREADY NEAR STATE LINE. HAVE CHANGED HEADLINE TO WINTER WEATHER ADVISORY FOR MICHIGAN COUNTIES...FURTHER SOUTH WILL CONTINUE WITH FREEZING RAIN ADVISORY WITH A MENTION OF BRIEF PL/SN MIX. BUT PRIMARILY ZR AS PTYPE. IN WAKE OF WAVE LATER THIS AM...IN MICHIGAN SHOULD SEE COLUMN REVERT TO FZRA PROFILE PER RUC/GFS SOUNDINGS WITH LACK OF SIGNIFICANT LIFT/COOLING. KEPT MAX TEMPS CLOSER TO A BIT BELOW COOLER MAV GUIDANCE WITH SNOW/ICE COVER AND LOW LEVEL THERMAL BAROCLINIC ZONE SETTING UP FURTHER SOUTH THAN ETA. PREFERENCE LIES MORE TOWARD CONSISTENT GFS WITH THIS RESPECT. LATER TONIGHT ANOTHER STRONGER SHOT OF I300 LIFT WITH GOOD MOISTURE TAP OF 5-6.5 G/KG ACROSS LOWER OHIO VALLEY AND HAVE BUMPED POPS TO 100 PERCENT CATEGORICAL BUT NO CHANCE TO BEAT MAV WITH 97-100 POPS. FOCUS SHIFTS LATER TONIGHT WITH QPF/WARMING TEMPS TO START OF RUNOFF/FLOOD ISSUES WITH WIDESPREAD SWE OF 1-2 INCHES PLUS ACROSS CWA AND ANTICIPATE WIDESPREAD BASIN AVERAGE RAINFALL TOTALS OF 0.5-1 INCHES BY WEDNESDAY NIGHT. THUS HAVE ISSUES FLOOD WATCH FOR POTENTIALLY SIGNIFICANT FLOODING LATE TONIGHT AND CONTINUE THROUGH WEDNESDAY NIGHT. && .LONG TERM... WEDNESDAY THROUGH MONDAY MAJOR PATTERN CHANGE WILL TAKE PLACE IN THE EARLY PART OF THE EXTENDED PERIOD WITH A RETURN TO BELOW NORMAL TEMPS BY THURSDAY NIGHT. PATTERN...THE NEGATIVE PNA PATTERN OF THE PAST FEW WEEKS WILL FLIP INTO A MORE TYPICAL MID WINTER POSITIVE PNA PATTERN BY THE END OF THIS WEEK. GFS ENSEMBLE MEAN PNA INDEX FORECAST SHOWING HIGH CONFIDENCE IN THIS PATTERN ADJUSTMENT. A STRONG PACIFIC CUTOFF LOW NOW MOVING ONSHORE INTO CALIFORNIA WILL EJECT THROUGH THE SOUTHWEST US AND INTO THE PLAINS BY MIDWEEK. THIS SYSTEM WILL PHASE WITH A STRONG NORTHERN STREAM SHORTWAVE DROPPING SOUTHEAST THROUGH THE CANADIAN PRAIRIES WITH A RAPIDLY DEEPENING SURFACE LOW CUTTING THROUGH THE LAKES WED NGT AND THURS. THE POLAR VORTEX WILL DROP INTO PLACE BEHIND THIS SYSTEM AND TAKE UP ITS TYPICAL MID WINTER RESIDENCE NEAR HUDSON BAY BY THE END OF THE WEEK. GFS ENSEMBLE MEAN FORECAST OF THE NAO AND AO INDICES INDICATING A GENERAL TREND TOWARDS A MORE NEGATIVE PHASE OF THE NAO BY LATE JANUARY SUGGESTING THAT THE COLDER PATTERN MAY BEGIN TO LOCK INTO THE EASTERN HALF OF THE CONUS. DEEP SOUTH FLOW AHEAD OF THE PACIFIC SYSTEM WILL DEVELOP ON WED. 925MB TEMPS SOAR TO +12C WHICH WOULD SUPPORT UPPER 50S EVEN WITH PURELY MOIST ADIABATIC MIXING. WARM SECTOR WILL BE MOIST AND AMPLE CLOUD COVER SHOULD KEEP TEMPS ON THE MORE CONSERVATIVE SIDE OF GUIDANCE NUMBERS WITH LOW 50S NORTH AND MID 50S SOUTH. INGREDIENTS COMING TOGETHER FOR A HEALTHY PERIOD OF RAIN WED NIGHT. PLUME OF ANOMALOUSLY MOIST AIR ADVECTS INTO THE CWA WITH PWATS OF OVER 1 INCH. LARGE SCALE LIFT WILL INCREASE OVERNIGHT WITH ADVANCING MID LEVEL TROUGH AND ASSOCIATED JET DYNAMICS. THIS WILL COMBINE WITH STRONG LOW LEVEL FRONTOGENETICAL FORCING TO PRODUCE A BAND OF DEEP LIFT ALONG THE SURFACE FRONT. ENOUGH DYNAMICS AND DEEP MOISTURE TO CONTINUE WITH MENTION OF ISOLATED THUNDER WITH TOTAL TOTALS AROUND 50. STRONG FROPA THURSDAY MORNING. GFS/CANADIAN GEM/ETA IN GOOD AGREEMENT WITH TIMING OF SURFACE FRONT WITH THE FRONT BISECTING THE CWA AT 12Z THURS. ECMWF A LITTLE SLOWER AND DISCOUNTED FOR NOW. THIS MAKES THE MAX TEMP FORECAST INTERESTING FOR THURSDAY AS JUST A FEW HOURS IN TIMING WILL MAKE A 20+F DIFFERENCE. WILL START TEMPS OFF IN THE UPPER 40S EAST TO MID/UPPER 30S WEST WITH FALLING TEMPS ALL DAY IN VERY STRONG CAA REGIME. BEST FORCING SHIFTS QUICKLY EAST OF THE CWA DURING THE MORNING. WILL CARRY LIKELY POPS EARLY IN THE EAST THEN TAPER POPS BACK TO CHANCE WITH SKIES BECOMING PARTLY CLOUDY BY AFTERNOON WITH SURFACE RIDGE BUILDING IN BEHIND SURFACE FRONT. THURSDAY NIGHT THROUGH THE WEEKEND A COLD ARCTIC AIRMASS WILL DOMINATE THE CWA. NO WEATHER TO WORRY ABOUT SYNOPTICALLY...SO OUR ATTENTION TURNS TO THE MESOSCALE. GFS SHOWING 850MB TEMPS IN THE -20C TO -24C RANGE POURING ACROSS LAKE MICHIGAN THURS NGT THROUGH SAT NGT. SYNOPTIC PATTERN WOULD SUGGEST WESTERLY FLOW WITH RELATIVELY LOW INVERSION HEIGHTS AND VERY LIMITED AMBIENT MOISTURE. LAKE EFFECT BANDS WILL HAVE TO OVERCOME SHORT FETCH AND SPARSE SYNOPTIC MOISTURE AVAILABILITY. HAVING SAID THAT...WEAK SHORTWAVES AND SURFACE TROUGHS ROTATING THROUGH THE MEAN NW FLOW ALOFT CAN SIGNIFICANTLY IMPROVE THE LAKE EFFECT SETUP AT TIMES IN THIS KIND OF PATTERN. THESE SHORTWAVES CANNOT BE TIMED THIS FAR IN ADVANCE. FOR NOW WILL KEEP CHANCE POPS IN COUNTIES FAVORED BY WESTERLY FLOW THROUGH THE FIRST HALF OF THE WEEKEND. SUB ZERO LOW TEMPS WILL BE POSSIBLE ON NIGHTS WHEN SKIES CLEAR AND WINDS ARE CALM. BEST CHANCE APPEARS TO BE FRIDAY NIGHT INLAND AWAY FROM LAKE EFFECT CLOUDS. && .AVIATION... PER 88D AND RUC/ETA BEST SHOT OF UVM ACROSS SBN AREA NEXT FEW HOURS WITH MIX SNPL WITH DYNAMIC COOLING OF LAYER. THEN COLUMN WARMS FOR MORE FZRA PROFILE. KEPT FWA ALL RAIN. CIGS WILL CONTINUE DOWNWARD TREND AND HAVE LIFR MOST OF DAY WITH SATURATED COLUMN NORTH OF WARM FRONT AND UPSTREAM OBS AND GUIDANCE SUGGESTING PRIMARILY LIFR. LATER TONIGHT ANOTHER SHOT OF BETTER UVM WITH HEAVIER RAIN...THOUGH BETTER MIXING MAY BRING CIGS UP A BIT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FREEZING RAIN ADVISORY THROUGH NOON FOR ZONES INZ003>009...INZ012...INZ014...INZ016. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. MI...WINTER WEATHER ADVISORY THROUGH NOON FOR ZONES MIZ077>081. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. OH...FREEZING RAIN ADVISORY THROUGH NOON FOR ZONES OHZ001>002...OHZ004>005. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. && $$ SHORT TERM/AVIATION...MURPHY LONG TERM...HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 AM EST TUE JAN 11 2005 .AVIATION... PER 88D AND RUC/ETA BEST SHOT OF UVM ACROSS SBN AREA NEXT FEW HOURS WITH MIX SNPL WITH DYNAMIC COOLING OF LAYER. THEN COLUMN WARMS FOR MORE FZRA PROFILE. KEPT FWA ALL RAIN. CIGS WILL CONTINUE DOWNWARD TREND AND HAVE LIFR MOST OF DAY WITH SATURATED COLUMN NORTH OF WARM FRONT AND UPSTREAM OBS AND GUIDANCE SUGGESTING PRIMARILY LIFR. LATER TONIGHT ANOTHER SHOT OF BETTER UVM WITH HEAVIER RAIN...THOUGH BETTER MIXING MAY BRING CIGS UP A BIT. && .UPDATE... DICEY SITUATION THIS EVENING W/MARGINAL TEMPS IN PLACE AHD OF ROBUST MID LVL SW TROF UPSTREAM OVR IL. LG SCALE JET SEGMENT OVR LKS PROGGED TO AID INCREASING FRONTOGENETICAL RESPONSE THROUGH 12Z ALG E-W ORIENTED THERMAL TROF. ALREADY SIG PRECIP DVLPMNT OCCURRING BACK W OVR ERN IA/WRN IL IN RESPONSE TO RAMPING LG SCALE LIFT. DILEMMA LIES W/MARGINAL TEMPS ATTM BUT ARRIVAL OF SIG PRECIP W/UPR 20 DEWPOINTS IN PLACE SHLD ALLOW FOR SOME DIABATIC ADJUSTMENT TO SFC TEMPS TO BELOW FREEZING WITHIN CURRENT ADVISORY AREA. ZONE UPDATE OUT SHORTLY TO INCREASE POPS AFTER MIDNIGHT. SHLD SEE WIDESPREAD UP TO 1/4 INCH AMTS WITHIN ADVISORY AREA OVERNIGHT. && .PREV.DISCUSSION... SHORT TERM... TONIGHT THROUGH TUESDAY NIGHT WILL ISSUE FREEZING RAIN ADVISORY FOR AREA NORTH OF A KNOX TO DEFIANCE LINE AFTER MIDNIGHT THRU TUESDAY MIDDAY. EXPECT SHORT WAVE OVER SOUTHERN PLAINS TO MOVE NWWD OVER THE WARNING AREA TONIGHT. IT WILL CAUSE LIGHT PRECIPITATION TO DEVELOP...MAINLY AFTER MIDNIGHT. ETA MODEL SOUNDINGS-BEST WITH LOW LEVEL RESOLUTION-SUGGEST AIR TO WARM ABOVE FREEZING BY MIDNIGHT...WHILE SURFACE TEMPS REMAIN BLO. THUS PRECIP SHOULD FALL AS FREEZING RAIN. SHOULD FALL AS ALL RAIN SOUTH OF THE ADVISORY LINE...BUT NORTH OF THAT LINE COULD START AS SLEET/SNOW/FREEZING MIX. ONLY EXPECTING A FEW HUNDREDTHS OF AN INCH OF MELTED PRECIP...SO ICE ACCRUALS SHOULD BE LIGHT. FREEZING RAIN WL CHANGE TO RAIN BY MIDDAY AS TEMPS WARM ABOVE FREEZING. EXPECT RAIN TO CONTINUE INTO TUESDAY NIGHT AS NEXT IN SERIES OF SHORT WAVES MOVES INTO AREA AND FRONTAL BOUNDARY TO THE SOUTH OF OUR AREA INCHES NWD. LONG TERM... A WARM FRONT WILL BE MOVING NORTHWARD THROUGH THE AREA TUESDAY NIGHT. THIS WILL BRING A GOOD SHOT OF RAIN TO THE AREA. THEN ON WEDNESDAY THIS FRONT MOVES AWAY FROM THE AREA AND HAVE A LOWER POP CHANCE IN THE MORNING HOURS BETWEEN THE EXITING WARM FRONT AND AN APPROACHING COLD FRONT FROM THE WEST. DURING THE DAY WEDNESDAY A LOW AND COLD FRONT WILL BE APPROACHING THE REGION. THEN RAIN WILL COME BACK INTO THE PICTURE AS THAT COLD FRONT AND LOW GET CLOSER LATER WEDNESDAY. THE COLD FRONT WILL THEN BE PASSING EASTWARD THROUGH THE REGION LATE WEDNESDAY NIGHT. SOME THUNDER MAY BE HEARD WITH THE PASSAGE OF THE COLD FRONT; BUT INDICATIONS FOR THUNDER ARE RATHER WEAK. MAINLY JUST RAIN. BUT THE POSSIBILITY IS THERE. THEN REALLY GOOD COLD AIR ADVECTION ON THURSDAY AFTER THAT COLD FRONT MOVES TO OUR EAST. EXPECTING THE HIGH TEMPERATURE FOR THURSDAY TO OCCUR RATHER EARLY IN THE MORNING AND FOR TEMPERATURES TO DROP THROUGHOUT THE DAY ON THURSDAY. ALSO AFTER THE COLD FRONT IT WILL BE RATHER COLD FOR THE REST OF THE WEEK. HIGH PRESSURE WILL BE CENTERED TO OUR WEST FOR FRIDAY AND SATURDAY. THE NORTHWEST WIND WILL GIVE OUR NORTHERN COUNTIES A CHANCE FOR SOME LAKE EFFECT SNOW. ELSE ALSO EXPECTING SUNDAY AND MONDAY TO BE DRY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FREEZING RAIN ADVISORY FOR THIS EVENING THROUGH TUESDAY MORNING FOR ZONES INZ003>009...INZ012...INZ014...INZ016. MI...FREEZING RAIN ADVISORY FOR THIS EVENING THROUGH TUESDAY MORNING FOR ZONES MIZ077>081. OH...FREEZING RAIN ADVISORY FOR THIS EVENING THROUGH TUESDAY MORNING FOR ZONES OHZ001>002...OHZ004>005. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 249 AM MST TUE JAN 11 2005 .DISCUSSION...THE 09Z SURFACE CHART PLACES HIGH PRESSURE BEHIND A FRONT WHICH HAS REMAINED NEARLY STATIONARY OVER EASTERN COLORADO AND THE NORTHERN TEXAS PANHANDLE. OBSERVATIONS NEAR THIS FRONT ARE REPORTING AREAS OF DENSE FOG EARLY THIS MORNING. A TROUGH OF LOW PRESSURE WAS SITUATED ALONG THIS FRONT FROM NORTHCENTRAL COLORADO TO SOUTHWEST OKLAHOMA. AN UPPER LOW CAN BE SEEN ON WATER VAPOR JUST OFF THE NORTHERN CALIFORNIA COAST. AT UPPER LEVELS...FLOW WILL BE SOUTHWEST TODAY. TONIGHT THE UPPER LOW WILL MOVE INTO THE COLORADO ROCKIES AND INTO SOUTHWEST KANSAS BY WEDNESDAY. THE UPPER LOW SHIFTS EAST WITH NORTHWEST FLOW OVER THE AREA FROM WEDNESDAY NIGHT THROUGH EARLY FRIDAY MORNING. ENERGY EJECTING OUT OF THE LOW WILL PROVIDE UPWARD VERTICAL VELOCITIES OVER THE AREA LATE TONIGHT/WEDNESDAY. AT THE SURFACE...THE BATTLEGROUND FOR COLD AIR VERSUS WARM AIR WILL CONTINUE TO REMAIN OVER THE EASTERN COLORADO COUNTIES TODAY. TONIGHT A LOW WILL MOVE INTO EASTCENTRAL COLORADO AND THEN MOVE INTO SOUTHWEST KANSAS. THE SURFACE LOW SHIFTS INTO SOUTHCENTRAL KANSAS ON WEDNESDAY BEFORE PULLING OUT WEDNESDAY NIGHT. HIGH PRESSURE WILL RIDGE INTO THE AREA THURSDAY MORNING BEHIND A FRONT AND CONTINUE THROUGH THURSDAY NIGHT. MAIN CONCERNS FOR THIS FORECAST IS EXTENT AND TIMING OF DENSE FOG THIS MORNING AND POPS/SNOW AMOUNTS TONIGHT. OF COURSE TEMPERATURES WILL CONTINUE TO BE AN ISSUE TODAY WITH GUIDANCE STILL TOO WARM. THERE IS STILL A SNOW FIELD OF AROUND AN INCH OVER PARTS OF THE NORTHERN 2 TIERS OF COUNTIES. THE RUC/ETA 12 INDICATE THAT THE DENSE FOG SHOULD REMAIN IN THE CURRENT ADVISORY AREA AND VISIBILITIES SHOULD IMPROVE AFTER 15Z. PLAN TO CONTINUE CURRENT DENSE FOG ADVISORY (DETAILS BELOW). FORCING FOR THE SYSTEM COMING IN WEDNESDAY IS BEST DESCRIBED BY FRONTOGENESIS NORTH OF INTERSTATE 70. ISENTROPIC UPGLIDE IS NOT A FACTOR AND UPSLOPE IS ONLY SURFACE BASED. THE UPPER TROUGH MOVES THROUGH QUICKLY AND GFS MODEL SOUNDINGS DRY OUT QUICKLY WEDNESDAY AFTERNOON/EVENING. DO NOT SEE ANY REASON TO EXTEND POPS/WEATHER INTO WEDNESDAY EVENING. SYSTEM PULLS THROUGH QUICKLY WITH NORTHWEST FLOW/SUBSIDENCE. QPF AMOUNTS INDICATE THAT SNOWFALL SHOULD RANGE FROM 1 TO 2 INCHES. LATEST POP GUIDANCE INDICATES HIGH CHANCE TO LIKELY POPS...BUT WILL HOLD OFF ON ANYTHING GREATER THAN CHANCE POPS FOR NOW SINCE THE LOW IS STILL JUST OFF THE CALIFORNIA COAST. THIS SEEMS TO BLEND WELL WITH SURROUNDING OFFICES. ONE LAST CONSIDERATION IS THE POSSIBILITY OF NEEDING A WIND ADVISORY WEDNESDAY AFTERNOON. THE LATEST GFS MOS INDICATES THAT SUSTAINED WINDS COULD MEET/EXCEED 30 MPH. FWC/MET GUIDANCE STAY BELOW THIS THRESHOLD BUT THIS WILL NEED TO BE MONITORED WITH SUCCEEDING RUNS. 700MB WIND/850MB WINDS ARE IN PHASE BUT MOSTLY CLOUDY SKIES SHOULD LIMIT MIXING AND SUBSIDENCE IS NOT ALL THAT STRONG. HOWEVER WILL ADJUST GRIDS FOR WINDY CONDITIONS WEDNESDAY AFTERNOON. MET/MAV GUIDANCE IS STILL TOO WARM EVEN THOUGH IT HAS COME DOWN IN RECENT RUNS. PREFER ETA12 SURFACE TEMPERATURES. THE UKMET SEEMS TOO COLD IN THE EASTERN COLORADO COUNTIES TODAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...DENSE FOG ADVISORY THIS MORNING WEST OF HIGHWAY 27 THROUGH 18Z. NE...DENSE FOG ADVISORY THIS MORNING FOR DUNDY COUNTY THROUGH 18Z. CO...DENSE FOG ADVISORY THIS MORNING FOR ALL OF EAST CENTRAL COLORADO THROUGH 18Z. && $$ FS ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 427 AM EST TUE JAN 11 2005 .DISCUSSION... WATER VAPOR IMAGERY AND RUC SHOWING A ZONAL FLOW ACROSS SOUTHERN CANADA AND NORTHERN CONUS. WEAK ELONGATED SHORTWAVES ARE RACING ALONG THIS FLOW AND ARE OVER NORTHERN MINNESOTA AND LAKE SUPERIOR THIS MORNING. A LOW IS MOVING INTO NORTHERN CALIFORNIA. SURFACE ANALYSIS INDICATE A RIDGE ACROSS THE FORECAST AREA STRETCHING FROM A HIGH CENTER OVER EAST CENTRAL ONTARIO. THE RIDGE EXTENDS INTO THE DAKOTAS. A LOW CENTER IS DEVELOPING OVER ALBERTA WITH A COLD FRONT DRAPED INTO THE NORTHERN HIGH PLAINS. ANOTHER LOW IS DEVELOPING OVER COLORADO THIS MORNING AND BECOMING MORE DEFINED. AREA RAOBS INDICATE AN INVERSION AROUND 900MB. THE MODELS IN FAIR AGREEMENT THROUGH 60 HOURS. THE SHORTWAVE OVER LAKE SUPERIOR WILL SHIFT EAST TODAY. THE LOW OVER CALIFORNIA WILL SHIFT INTO THE GREAT BASIN. WEAK SHORTWAVES BEING EJECTED OUT AHEAD OF THIS LOW WILL MOVE INTO THE DAKOTAS AND INTO THE SALT LAKE BASIN. THE SURFACE HIGH OVER EASTERN ONTARIO WILL SWING INTO NORTHERN ATLANTIC STATES. THE LOW OVER ALBERTA WILL BECOME MORE FOCUSED AND MOVE VERY LITTLE. THE LOW OVER THE SOUTHWEST STATES WILL BECOME FOR ORGANIZED OVER THE COLORADO. THE FLOW AHEAD OF THE LOWS TO THE WEST AND THE EAST COAST HIGH WILL DRAW WARM AIR INTO THE AREA. THERE WILL BE A WEAK SURFACE TROUGH EXTENDING ACROSS THE OHIO VALLEY BY LATE AFTERNOON. THIS WILL CAUSE THE WINDS TO BECOME EASTERLY THROUGH THE DAY AND PRODUCE WARM AIR ADVECTION PUSHING TEMPERATURES TO NEAR 30. 275K ISENTROPIC ANALYSIS SHOWING WEAK ASCENT IN THE LOW LEVEL OVER THE U.P. THIS MORNING. MEAN SURFACE TO 900MB RH WILL BE 80 TO 85 PERCENT ACROSS CENTRAL U.P. MOISTURE IS RATHER LIMITED. THUS EXPECT TO SEE SOME CLOUDS AND ONLY A CHANCE OF LIGHT SNOW. THE SHORTWAVE OVER THE DAKOTAS WILL RACE ACROSS THE FORECAST AREA THIS EVENING. THE ISENTROPIC ASCENT WILL INCREASE OVER THE FORECAST AREA THIS EVENING. 275K ISENTROPIC SURFACE CONDENSATION PRESSURE DEFICIT WILL LOWER TO 20MB BY EARLY EVENING AND TO AROUND 10MB BY MIDNIGHT OVER THE SOUTHERN U.P. THIS ALONG WITH THE LOW LEVEL ASCENT WILL PRODUCE PRECIPITATION. ETA SOUNDING FORECAST INDICATES A SATURATE CONDITION SURFACE TO 700MB. GFS IS A LITTLE DRIER AROUND 850MB TONIGHT. BOTH SOUNDINGS INDICATE TEMPERATURES WILL BE NEARLY ISOTHERMAL FROM SURFACE TO 700MB AND BE BETWEEN -3C AND -8C. ASCENT AT THE LOW LEVELS...SHORTWAVE MOVING THROUGH THE U.P. BY LATE EVENING ALONG WITH AVAILABLE LOW LEVEL MOISTURE...CONDITIONS LOOK FAVORABLE FOR SNOW. THE LOW OVER COLORADO WILL BECOME MORE ORGANIZED ALONG THE COLORADO/KANSAS BORDER BY WEDNESDAY MORNING. SEVERAL WEAK SHORTWAVES CONTINUE TO BE EJECTED OUT AHEAD OF THIS LOW. THE SURFACE LOW OVER ALBERTA WILL MOVE INTO SOUTHERN SASKATCHEWAN. THE CLOSED LOW OVER WESTERN KANSAS WILL MOVE TO NORTHEAST KANSAS BY LATE AFTERNOON WEDNESDAY. A SHORTWAVE BEING EJECT OUT AHEAD OF THE LOW WILL SLIDE OVER THE U.P. A SURFACE LOW OVER KANSAS WILL MOVE INTO EASTERN IOWA...WHILE THE LOW OVER SASKATCHEWAN MOVES INTO SOUTHERN MANITOBA. WARM MOIST AIR WILL CONTINUE TO ADVECT INTO THE FORECAST AREA ON WEDNESDAY AHEAD OF THE CENTRAL PLAINS LOW. A WEAK FRONTAL SYSTEM OVER THE NORTHERN OHIO RIVER VALLEY IN THE MORNING WILL MIGRATE NORTH INTO LOWER MICHIGAN. ISENTROPIC ASCENT WILL INCREASE NORTH OF THE FRONTAL SYSTEM AND OVER THE THE FORECAST AREA. CONDENSATION PRESSURE AND LOW LEVEL RH INDICATES ADEQUATE MOISTURE TO KEEP PRECIPITATION GOING. QUESTION IS THE TYPE OF PRECIPITATION. ETA FORECAST SOUNDING IS A LITTLE COOLER THAN GFS FAVORING MIXED PRECIPITATION ON WEDNESDAY...WHERE ASK GFS FAVOR SNOW CHANGING TO RAIN ACROSS THE U.P. THE GFS SOLUTION IS MORE IN LINE WITH ECMWF/UKMET/CMC THUS WILL GO WITH THE CONSENSUS AND FAVOR THE LITTLE WARMER GFS AND LOOK FOR THE SNOW CHANGING TO RAIN. THE SHORTWAVE OVER KANSAS WILL SHIFT OVER THE FORECAST AREA WEDNESDAY NIGHT WHILE THE OVER SASKATCHEWAN SHIFTS INTO SOUTHERN MANITOBA. THE SURFACE LOW OVER IOWA WILL RACE NORTHEAST AND MERGE WITH THE LOW MOVING ACROSS SOUTHERN CANADA AND REACH EAST CENTRAL ONTARIO BY THURSDAY MORNING ALL THE WHILE DRAGGING A COLD FRONT INTO THE EASTERN U.P. THE AIR MASS WILL DRY OUT QUICKLY FROM THE WEST BEHIND THE FRONT. THE WINDS WILL SHIFT NORTHWEST FOLLOWING THE FROPA. THE RAIN WILL CHANGE BACK TO SNOW. A 40 KNOT LOW LEVEL JET WILL SHIFT OUT OF THE NORTHWEST AND MOVE OVER THE U.P. ISENTROPIC ANALYSIS INDICATES THAT SOME OF THIS WIND WILL DESCENT TO SURFACE BEHIND THE FRONT. THUS LOOKING FOR AN INCREASE OF WIND. THUS LOOKING FOR SOME BLOWING SNOW OVER THE KEWEENAW AND PARTS OF EASTERN U.P. WITH MORE OF THE WINDS MIXING TO SURFACE OVER THE RELATIVELY WARM LAKE SUPERIOR...GALES LOOK LIKELY AS WELL. A SURFACE RIDGE WILL PUSH INTO THE NORTHERN PLAINS. THE ONTARIO SURFACE LOW WILL MOVE NORTH INTO HUDSON BAY. COLD AIR FROM NORTHERN CANADA WILL WRAP INTO THE UPPER GREAT LAKES REGION BEHIND THE LOW. THE GFS FORECAST SOUNDING INDICATE A -30C 850MB THERMAL TROUGH WILL PUSH INTO NORTHERN MINNESOTA AND WESTERN U.P. ON THURSDAY. LAKE EFFECT SNOW WILL KICK PRODUCING LAKE EFFECT SNOW OVER THE AREAS OF THE U.P. PRONE TO LES WITH A NORTHWEST FLOW. THE EXTENDED FORECAST LOOKS REASONABLE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 342 AM EST TUE JAN 11 2005 .DISCUSSION... AN EXTREMELY COMPLEX EVENT UNFOLDING WITH A VARIETY OF PRECIP TYPE ISSUES THE NEXT 12-18 HOURS TO BE FOLLOWED BY A STRONG LINE OF CONVECTION AND HEAVY RAINFALL POTENTIAL...WHICH WILL LEAD TO THE ARCTIC BLAST THURSDAY INTO THE UPCOMING WEEKEND. WATER VAPOR AND RADAR IMAGERY IMAGERY SHOW SEVERAL PLAYERS WORKING TOGETHER FOR THIS NARROW, YET INTENSE, REGION OF PRECIPITATION. SHORT WAVE, ALBEIT BECOMING MORE STRUNG OUT, WAS PROGRESSING ACROSS ILLINOIS/INDIANA. TO OUR NORTH A DEPARTING 130KT 300MB JET WAS AIDING IN THE LIFT PROCESS ACROSS NORTHERN INDIANA AND OUR FIRST SHOT OF WARM ADVECTION. LATEST RUC ANALYSIS SHOWS THIS NICELY WITH TIGHTENING THERMAL GRADIENT IN THE 800-700MB LAYER AND 2D-FGEN FORCING WAS VERY IMPRESSIVE ACROSS THE MICHIGAN STATE LINE. HOWEVER, ANOTHER REGION OF THERMALLY INDUCED FGEN WAS WEAKENING TO OUR NORTH AS THERMAL STRUCTURE IS EXPECTED TO WEAKEN TOWARD 12Z. TAKING THE LATEST RUC, REGION OF FGEN AND OMEGA WILL PERSIST ACROSS OUR SOUTHERN 4 COUNTIES THROUGH THIS MORNING AND WEAKEN DURING THE AFTERNOON AS WAVE DEPARTS TO OUR EAST. AS THE SURFACE, 1012MB LOW WAS NEAR KSTL WITH WARM FRONT EXTENDING EAST INTO KENTUCKY WITH 1027MB HIGH JUST EAST OF GEORGIAN BAY. TODAY... WE WILL CONTINUE WITH OUR ADVISORY FOR THOSE SOUTHERN 4 COUNTIES AND EXPAND IT A TIER NORTH THIS MORNING AS THEY WILL REMAIN NEAR THE FGEN FORCING AND FAVORABLE POSITION OF OUR DEPARTING JET THROUGH THE REMAINDER OF THE MORNING HOURS. MODELS ARE FAIRLY SIMILAR ON THIS SITUATION BUT DISAGREE WITH SUBTLE, YET SIGNIFICANT, TEMPERATURE PROFILES. SOME ABOVE 0C TEMPS @ 925MB WERE ATTEMPTING TO MOVE INTO ADG-TTF VICINITY WITH THE LATEST TAMDAR DATA FROM DTW SHOWING SIGNS OF NEAR 0C BETWEEN 800-900MBS. WITH THAT IN MIND...THINK WE WILL SEE A LITTLE MORE OF A MIX TO HOLD DOWN OUR ACCUMULATIONS SOMEWHAT BUT IT WILL BE CLOSE. WITH THIS AMOUNT OF LIFT AND UPSTREAM RADARS VERY BRIGHT THIS MORNING...WE COULD SEE ACCUMULATIONS APPROACH 6" IF WE ARE ABLE TO KEEP THE LAYERS BELOW 0C (WE HAVE 4 G/KG IN THE 850-700MB LAYER WITH IMPRESSIVE ISENTROPIC LIFT IN THIS LAYER). THIS WILL DOMINATE OUR WEATHER TODAY AS WE WILL SEE THIS SYSTEM AND DYNAMICS WEAKEN AND PASS TO OUR EAST DURING THE AFTERNOON. HOWEVER, AS WE LOSE SOME THE MID LEVEL MOISTURE (AOA 700MB), ENOUGH SHEAR IN THE PROFILE SUGGESTS SOME FREEZING DRIZZLE/FLURRIES ACROSS THE NORTH. TEMPERATURES TODAY WOULD EXPECT TO BE COOLER THAN THOSE ADVERTISED IN THE LATEST MOS NUMBERS. BASED ON TRAJECTORIES AND EXTENSIVE CLOUD SHIELD, WOULD THINK TEMPS HOLDING THE LOWER-MIDDLE 30S. TONIGHT... THE POTENTIAL EXISTS FOR ANOTHER HEADLINE ACROSS THE NORTHERN HALF OF OUR CWA BUT THIS WILL BE REFINED WITH THE UPCOMING DAY SHIFT. LATEST GUIDANCE SUGGESTS THE NEXT BIG SURGE OF WARM THETA-E ADVECTION TO OCCUR TOWARD 06Z AS POWERFUL PACIFIC SYSTEM EJECTS INTO THE PLAINS. SHARP 850MB FRONT WILL SWING NORTH OVERNIGHT AND LIKELY PRODUCE SOME PRECIPITATION BEFORE THE MAIN SURFACE WARM FRONT APPROACHES. WITH THAT, WE HAVE AN ISSUE WITH NEAR SURFACE TEMPS. SOUNDINGS AND 3-HOURLY MOS VALUES SUGGEST WE COULD HAVE AN ACCUMULATING ICE EVENT UNFOLDING ACROSS THE NORTHERN HALF. THE QUESTION WILL BE TIMING OF THE WARM AIR AND THE PRECIP AMOUNTS AS USUALLY THE ETA HAS A BETTER HANDLE ON LOWER LEVEL TEMPS THAN THE GFS IN THESE TYPES OF SITUATIONS. HOWEVER, WE COULD HAVE ENOUGH LATENT HEAT RELEASE OF ANY FROZEN PRECIP (WHICH WOULD BE ON THE LIGHT SIDE INITIALLY) TO RAISE TEMPS JUST ABOVE FREEZING TO RESULT IN LITTLE OR ANY PROBLEMS. AS PREVIOUSLY MENTIONED, THIS WILL NEED TO BE MONITORED VERY CLOSELY AND WE WILL MAKE MENTION IN THE HWO. WEDNESDAY... WE FINALLY (WE HOPE) LOSE OUR PRECIP TYPE ISSUES AS SURFACE WARM FRONT RACES NORTH. VERY IMPRESSIVE WARM ADVECTION (850MB JET IN EXCESS OF 50KTS) WITH ELEVATED FACTORS SUGGESTING WE WILL NEED TO ADD IN SOME THUNDER POTENTIAL. THE INITIAL SURGE WILL OCCUR IN THE MORNING BUT WITH STILL DEEP THETA-E AIR OVERHEAD DURING THE AFTERNOON, WE WILL CONTINUE WITH LIKELY POPS THRU THE DAY. WE SHOULD LOSE OUR SNOW COVER FAIRLY QUICKLY AND EXPECT TEMPS TO CLIMB THROUGH THE 40S. WE MIGHT HAVE A FAIRLY EXTENSIVE FOG EVENT EARLY ON BUT AS WE LOSE THE SNOW COVER...VISIBILITIES WILL SLOWLY COME UP IN THE AFTERNOON. WEDNESDAY NIGHT... POWERFUL SHORT WAVE HEADS INTO THE PLAINS WITH NEAR PHASING ACROSS THE WESTERN LAKES WITH POLAR WAVE DIVING SOUTH TOWARD THE DAKOTAS OVERNIGHT. WITH VERY STRONG SOUTHERLY WINDS ALOFT TRANSPORTING PWATS IN EXCESS OF 1" AND ELEVATED STABILITY FACTORS SUGGESTIVE OF A SQUALL LINE MOVING ACROSS LATE... WE WILL NEED TO MONITOR FOR DAMAGING WIND GUSTS AND FLOODING ACROSS THE ENTIRE REGION. TEMPERATURES WILL CONTINUE TO RISE INTO THE 50S FOR MOST LOCATIONS OVERNIGHT. THURSDAY... IF TIMING WORKS OUT... WE WILL TRULY EXPERIENCE THE 4-SEASONS IN A SPAN OF 12 HOURS. LINE OF CONVECTION RACES EAST EARLY IN THE MORNING WITH 50 DEGREE TEMPS AND BY AFTERNOON (AKA 00Z)... 850MB TEMPS WILL BE APPROACHING -15C ACROSS OUR WESTERN COUNTIES WITH SOME SNOW SHOWERS FROM LAKE MICHIGAN AND ANY AVAILABLE MOISTURE LEFT IN THE ATMOSPHERE. WITH SUCH A STRONG FROPA...ANOTHER ROUND OF DAMAGING WIND GUSTS IS POSSIBLE AS MIXING LAYER HEIGHTS QUICKLY CLIMB AND NOT TO MENTION THE STRONG DECENT. REMAINDER OF THE FORECAST LOOKS IN GOOD SHAPE (AND QUITE COLD). ANOTHER HEADLINE MAY BE NEEDED...IN THE FORM A WIND CHILL ADVISORY. WITH TEMPERATURES INTO THE LOWER SINGLE DIGITS AND WINDS STILL AROUND 15 KTS...WIND CHILL READINGS FALL TO DANGEROUSLY LOW -20F. THANKS FOR THE COLLABORATION GRR, IWX AND APX! && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...WINTER WEATHER ADVISORY...MIZ075-076-082-083...THROUGH 2 PM TODAY. SNOW ADVISORY...MIZ068>070...UNTIL NOON .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ BGM HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1205 AM EST TUE JAN 11 2005 .AVIATION... AN AREA OF SNOW...SLEET AND FREEZING RAIN ACROSS NORTHERN ILLINOIS WILL ADVANCE TO THE EAST OVER THE NEXT SEVERAL HOURS. THE STRONGEST LIFT WITHIN THE ENTRANCE REGION OF AN UPPER LEVEL JET WILL MOVE ALONG AND SOUTH OF THE I-94 CORRIDOR FROM 09Z THROUGH 18Z TUES. THE INTENSITY AND LOCATION OF THE HEAVIER BAND OF PRECIP WILL FLUCTUATE DURING THIS TIME PERIOD. AT THIS POINT... IT APPEARS THE STRONGEST LIFT WILL PASS THROUGH DTW AND DET BETWEEN 14Z AND 17Z. MODEL SOUNDINGS SUPPORT MAINLY SNOW THROUGH TUES MORNING... THEN GRADUALLY TURNING OVER TO SLEET AND RAIN DURING THE AFTERNOON. CEILINGS AND VISIBILITY WILL GRADUALLY DETERIORATE AFTER 09Z... WITH IFR CONDITIONS EXPECTED BY 12Z. THE LIFT WILL NOT BE AS STRONG ACROSS FNT AND MBS. BASED ON UPSTREAM OBSERVATIONS... I DO NOT EXPECT IFR CONDITIONS IN FNT AND MBS UNTIL 16Z TUES. && .UPDATE... ISSUED AT 928 PM. THE 00Z UPPER AIR PLOTS SHOWED A 130KT 300MB JET NEAR GEORGIAN BAY. ENTRANCE REGION DYNAMICS IS AIDING SOME MID FRONTOGENETICAL LIFT ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES... ALONG AND NORTH OF A FRONT OVER THE OHIO VALLEY. AREA RADARS SHOW TWO MAIN BANDS OF RETURNS ASSOCIATED WITH THIS LIFT. ONE EXTENDS FROM NEAR MSP TO CENTRAL MICHIGAN... WITH ONLY FLURRIES BEING REPORTED. THE SECOND AREA OF RETURNS ARC FROM SOUTHERN IOWA ACROSS NORTHERN IL TO CENTRAL IN. MAINLY RA AND FZRA IS OCCURRING WITH THIS FEATURE. THE HIGH PRESSURE OVER THE NORTHERN GREAT LAKES IS A LITTLE STRONGER THAN INDICATED BY EARLIER MODEL RUNS. THE 00Z SOUNDINGS FOR APX/GRB/DTX/DVN ALL WERE A LITTLE BIT DRYER BELOW 700MB AS A RESULT. MEANWHILE... THE 12Z AND 18Z RUC AND ETA VERIFIED THE THERMAL STRUCTURE ACROSS THE REGION RATHER WELL. FOR THE CURRENT ADVISORY... FEEL THERE WILL BE A LITTLE BIT MORE SNOW TO START THE EVENT THEN PREVIOUSLY THOUGHT. THIS IS DUE TO SLIGHTLY LOWER WET BULB HEIGHTS OVER SOUTHERN MICHIGAN. PERSISTENT MID LEVEL FRONTOGENETICAL LIFT OVER THE SOUTHERN LAKES SHOULD ALSO TIGHTEN THE THERMAL GRADIENT OVER THE OHIO VALLEY... WITH AGEOSTROPHIC FLOW HELPING TO ADVECT COLDER AIR INTO THE ADVISORY AREA. LIFT IS STILL EXPECTED TO MOVE INTO THE ADVISORY AFTER 06Z AND PERSIST OFF AND ON THROUGH 18Z TUE. THE WARM LAYER WILL SLOWLY LIFT NORTHWARD ON TUESDAY... CAUSING A GRADUAL CHANGE OVER TO SLEET AND FREEZING RAIN BY NOON... THEN ALL RAIN BY LATE AFTERNOON. BASED ON OBSERVATIONS AND LATEST GUIDANCE... WILL INCREASE TOTAL SNOWFALL TO 2 TO 4 INCHES AND EXPAND THE ADVISORY TO 2 PM TUES. WITH SPECIFIC HUMIDITIES OF 4 G/KG OVER THE SOUTH... LENAWEE AND MONROE COUNTIES MAY APPROACH WARNING CRITERIA TUES MORNING IF THE CHANGE OVER TO SLEET AND FZRA IS LATER. AS FOR THE M 59 COUNTIES... THE SOUNDING PROFILE LOOKS MAINLY LIKE SNOW THROUGH NOON TUES. WILL HOWEVER CUT BACK ACCUMULATIONS TO 1 TO 3 INCHES AS IT APPEARS THE BEST FRONTOGENETICAL FORCING TONIGHT WILL BE BOTH NORTH AND SOUTH OF THESE COUNTIES. MODEST LIFT WILL OCCUR TUES MORNING... BUT IS EXPECTED TO BE MUCH WEAKER THAN IN THE ADVISORY AREA. AND FOR I 69 COUNTIES AND POINTS NORTHWARD... THE AMOUNT OF DRY AIR ASSOCIATED WITH THAT HIGH WILL LIMIT THE AMOUNT OF SNOWFALL ACCUMULATION. I WILL THUS LOWER SNOWFALL CHANCES AND AMOUNTS CONSIDERABLY. LACK OF ANY SIGNIFICANT SNOWFALL REPORTS UPSTREAM SUPPORTS THIS. FOR TONIGHT/TUES MORNING... I WILL CARRY ACCUMULATIONS AN INCH OR LESS. THE UPDATED ZONES AND GRIDS WILL BE AVAILABLE BY 330 UTC (1030 PM). THANKS FOR THE COORDINATION GRR. && .SHORT TERM... ISSUED AT 350 PM. STORM SYSTEM OVER SW MISSOURI TO TRACK THROUGH THE OHIO VALLEY TONIGHT...DELIVERING A BURST OF PRECIPITATION TO SOUTHERN LOWER MICHIGAN OVERNIGHT INTO TOMORROW MORNING. LATEST WATER VAPOR IMAGERY INDICATING MID LEVEL MOISTURE BEGINNING TO STREAM INTO THE SOUTHERN GREAT LAKES. BEST ISENTROPIC LIFT (285-290 K) LOOKS TO BE OCCURRING AROUND 9Z OVER SW LOWER...AND AROUND 12Z OVER SOUTHEAST MICHIGAN. SPECIFIC HUMIDITIES CLIMB OVER 4 G/KG OVER THE SOUTHERN MICHIGAN BORDER...WITH AROUND 3 G/KG OVER CENTRAL LOWER MICHIGAN. BIG DIFFERENCES BETWEEN 12Z ETA/GFS. ETA INDICATING TWO DISTANT REGIONS OF LIFT (SEE 700 MB OMEGA)...ONE IN THE NORTH (KLDM-KMBS) AND THE MORE SIGNIFICANT FORCING IN THE TOWARD THE OHIO BORDER. 24 HOUR (18Z MONDAY-18Z TUESDAY) QPF TOTALS OUT OF GFS RANGE FROM 5 HUNDREDTHS NORTH TO 4 TENTHS OF AN INCH SOUTH. 12Z MESOETA IS A LOT MORE BULLISH WITH QPF FARTHER NORTH...INDICATING 0.15 INCHES TO 0.35 INCHES NORTH OF I-94. EVEN SO...ETA BUFKIT PROFILES INDICATE SATURATION WILL GENERALLY BE BELOW -10 C ISOTHERM...THUS WOULD NOT EXPECT HIGH SNOW TO LIQUID RATIOS. ALL SOUNDINGS (GFS/ETA/NGM/UKMET) POINT TO ALL SNOW NORTH OF I-94 TONIGHT...WITH ENOUGH WARM AIR COMING IN THE 2000 TO 5000 FOOT LAYER TO ALLOW FOR A MIX AND/OR CHANGEOVER TO SLEET AND FREEZING RAIN TOWARD THE SOUTHERN MICHIGAN BORDER. BECAUSE OF THIS WINTRY MIX...WILL ISSUE A WINTER WEATHER ADVISORY FOR I-94 CORRIDOR AND POINTS SOUTH. EXPECTING 1 TO 3 INCHES BEFORE THE CHANGEOVER OCCURS. HELD OFF ON ANY ADVISORY'S FARTHER NORTH...AS THE PRECIPITATION SHOULD BE ALL SNOW INTO TUESDAY MORNING. WILL CARRY ACCUMULATIONS OF 1 TO 4 INCHES IN THE ZONES NORTH OF I-94...BELOW ADVISORY CRITERIA. LIFT EXITS THE REGION TUESDAY MORNING...WITH SHORTWAVE RIDGING BUILDING IN FOR THE AFTERNOON HOURS. DEEP LOW LEVEL MOISTURE SUPPORTS A MENTION OF DRIZZLE...WITH LOCATIONS ALONG AND NORTH OF I-96 AT OR SLIGHTLY BELOW FREEZING FOR MUCH OF THE DAY. && .LONG TERM... SAME PROBLEMS REMAIN AS A SERIES OF DISTURBANCES LIFT INTO THE AREA OVER THE NEXT FEW DAYS. THIS WILL LEAD TO PERIODS OF RAINFALL...AND EVEN A CHANCE AT FREEZING RAIN TUESDAY EVENING IF TIMING OF THAT WAVE MATCHES UP WITH EVENING TEMPERATURES OF 30 OR SO. THE WINDOW FOR THIS WILL BE RELATIVELY BRIEF AS TEMPERATURES SLOWLY BUT STEADILY CLIMB THROUGH THE NIGHT...AND ON INTO EARLY THURSDAY MORNING FOR THAT MATTER. THE CONSENSUS ON THE PRECIPITATION EVENT ON TUESDAY NIGHT ACTUALLY DOES SUGGEST MOST OF THE QPF AFTER MIDNIGHT ONCE SURFACE TEMPERATURES ARE BASICALLY ABOVE FREEZING. HOWEVER...THIS WILL BE A CLOSE CALL. WILL BREAK OUT THE NIGHTTIME PERIOD FOR EVENING FREEZING RAIN MENTION NORTHERN 2/3 OF CWA...AND CONTINUE WITH RAIN OVERNIGHT. LIKELY POPS SEEM QUITE REASONABLE AT THIS TIME...AND WILL CARRY 60-70 POPS FOR THE PERIOD. SAME STORY FOR WEDNESDAY WITH RAIN...BY AND LARGE...LIKELY. ATTM... IT APPEARS THAT "EVENT" NUMBER ONE TUESDAY NIGHT WOULD LINGER INTO EARLY WED MORNING...WITH A RELATIVELY CALM DAYTIME PERIOD...FOLLOWED BY INCREASING RAIN COVERAGE LATE IN THE DAY INTO THE EVENING. WILL NOT GET CUTE THOUGH...AS TIMING IN SUCH A SITUATION SEEMS FUTILE. BIGGEST CHALLENGE REMAINS IN THE WEDNESDAY NIGHT AND THURSDAY TIME. HERE...SOUTHERN STREAM STORM LIFTS NORTHEAST ALONG LEADING EDGE OF EXPANDING ARCTIC TROF TO OUR WEST/NORTHWEST. THE RESULTANT SURFACE LOW DEEPENS RAPIDLY AS IT LIFTS ALONG ARCTIC COLD FRONT AS IT SURGES THROUGH LOWER MICHIGAN. WITH THIS SYSTEM COMES A GOOD SLUG OF RAIN LATE WEDNESDAY NIGHT INTO THURSDAY MORNING...WITH PERHAPS THE TAIL END OF THIS (OR MORE APPROPRIATELY...THE TRAILING AREA OF PRECIP W/ UPPER VORT) TURNING TO SNOW ON THURSDAY. WILL MAINTAIN EARLY MORNING HIGHS AROUND 50 ON THURSDAY...WITH TEMPS DOWN INTO THE TEENS/20S BY EVENING. THIS DRAMATIC TEMPERATURE DROP WILL COME ON VERY GUSTY WEST WINDS THURSDAY ON INTO THE EVENING. WILL UP WINDS A BIT...ALTHOUGH CURRENT FORECAST IS IN PRETTY GOOD SHAPE. WILL HAVE TO WATCH THIS PERIOD OF EVEN STRONGER WINDS THAN ARE FORECAST...WITH THAT STRONG OF A PRESSURE SURGE (+18MB RISES IN THE 6 HOUR PERIOD MIDDAY THURSDAY ON AVERAGE. TEMPERATURES CONTINUE ON DOWN FROM THERE AS ARCTIC AIR BUILDS IN ON THROUGH THE WEEKEND. NOT TOO MANY CHANGES HERE. JUST EDGED THE TEMPERATURES DOWN A BIT MORE FROM FRIDAY INTO SATURDAY...WITH A VERY SLOW MODERATION NEXT WEEK. EVEN SO...ARCTIC AIR REMAINS IN PLACE...SO DO NOT PLAN ON A SIGNIFICANT WARMUP. COLD...CYCLONIC FLOW PERSIST THROUGH THE FORECAST...WHICH WILL KEEP SCATTERED SNOW SHOWER CHANCES IN EVERY DAY. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...WINTER WEATHER ADVISORY...MIZ075-076-082-083...FROM MIDNIGHT TONIGHT THROUGH 2 PM TUESDAY. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ SF/DEG/SC HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OKLAHOMA 320 AM CST TUE JAN 11 2005 DIFFICULT FORECAST TO CONTINUE FOR THE NEXT 24-48 HOURS AS EXACT TIMING/MOVEMENT OF FRONTAL BOUNDARY REMAINS PROBLEMATIC. COLD SHALLOW AIRMASS PUSHING THROUGH FA THIS MORNING WITH BOUNDARY CURRENTLY LOCATED JUST NORTH OF AN XNA...MKO LINE. NORTH OF BOUNDARY TEMPERATURES WILL WARM LITTLE IF ANY DURING THE DAY WITH THE EXPECTED LOW CLOUDS/WEAK CAA. LEANING TOWARD THE LATEST RUC DATA GIVEN LATEST TRENDS...PUSHING FRONT FURTHER SOUTH THAN BOTH ETA/GFS. THEREFORE UNDERCUT GUIDANCE SEVERAL DEGREES TODAY AND TONIGHT NORTH OF EXPECTED FRONTAL POSITION. AS STRONG UPPER DISTURBANCE SHIFTS EAST IN THE SOUTHERN PLAINS... FRONT EXPECTED TO LIFT NORTHWARD LATE TONIGHT INTO WEDNESDAY WITH REGION IN LEFT FRONT QUAD OF 120KT UPPER JET. BOTH ETA/GFS SOLUTIONS LIFT WARM FRONT WELL NORTH...WITH ENTIRE FA IN WARM SECTOR WEDNESDAY AFTERNOON. TRENDED TOWARD THIS SOLUTION HOWEVER DIFFICULT ATTM TO SAY HOW FAR NORTH WARM FRONT WILL MAKE IT DURING THE DAY. STILL EXPECT SHOWERS/THUNDERSTORMS TO DEVELOP ALONG FRONT WEDNESDAY AFTERNOON WITH THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON/EVENING AS SQUALL LINE SWEEPS EAST THROUGH SOUTHEAST OKLAHOMA/NORTHWEST ARKANSAS. ALTHOUGH INSTABILITY WILL REMAIN SOMEWHAT MARGINAL WITH SBCAPES IN THE 1000-1200 J/KG RANGE...STRONG DEEP LAYER SHEAR...COUPLED WITH STEEP MID LAYER LAPSE RATES SUGGEST DAMAGING WIND/HAIL THREAT. GIVEN THE STRONG FORCING ALONG/AHEAD OF FRONT...STORMS MAY QUICKLY BECOME LINEAR...LIMITING THE OVERALL TORNADO THREAT. BEST CHANCE FOR SEVERE WILL BE ACROSS FAR SOUTHEAST OKLAHOMA/NORTHWEST ARKANSAS. EXTENDED...MODELS HAVE TRENDED SEVERAL DEGREES WARMER FRI/SUN WITH ARCTIC AIRMASS. FOR NOW JUST BUMPED TEMPS UP A FEW DEGREES DURING THIS TIME FRAME. HIGH PRESSURE SHIFTS EAST OF THE REGION BY MONDAY WITH WARMING TREND EXPECTED. NO OTHER MAJOR CHANGES TO THE EXTENDED WITH DRY FORECAST DAYS 3-7. PRELIM NUMBERS: TUL 41 38 64 30 / 20 20 60 20 FSM 61 52 68 36 / 20 20 70 60 MLC 57 50 68 34 / 20 20 60 30 BVO 38 33 61 27 / 20 20 60 30 FYV 54 48 65 32 / 20 20 70 60 BYV 56 49 64 32 / 20 20 70 60 MKO 54 48 66 33 / 20 20 60 30 MIO 41 40 63 29 / 20 20 70 60 F10 51 45 65 31 / 20 20 60 20 HHW 69 57 67 40 / 20 20 60 50 FORECAST ID= 12 .TSA WATCHES/WARNINGS/ADVISORIES... AR...NONE. OK...NONE. $$ ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 400 AM CST TUE JAN 11 2005 .SHORT TERM... COLD FRONT WITH MODIFIED ARCTIC AIR NOW SLICING THROUGH THE NERN FA HAVING JUST PASSED THROUGH CHILDRESS IN THE LAST HALF HOUR. SATELLITE IMAGERY AND MESONET OBS INDICATE THAT THE FRONT STILL HAS A DECENT PUSH TO IT...ESPECIALLY TO THE SOUTH ACROSS AREAS EAST OF THE CAPROCK...NOT SURPRISING GIVEN SHALLOW NATURE OF THE AIR MASS. ALL MODELS EXCEPT FOR THE RUC HAVE VERY POOR HANDLING OF THIS FEATURE AND HAVE THUS DISCOUNTED A SIGNIFICANT PORTION OF THE LOW LEVEL PROGGED MODEL FEATURES. AVE OPTED TO FOLLOW RUC SFC SOLUTION FAIRLY CLOSELY...BRINGING FRONT THROUGH MOST OF THE ROLLING PLAINS BY LATE MORNING. ON THE CAPROCK SWLY SFC FLOW SHOULD INCREASE BUT HIGH CLOUDS ARE EXPECTED TO KEEP WIND SPEEDS FROM MAXIMIZING THEIR POTENTIAL. EXPECT 10-20 OR 15-25 MPH WORDING TO DROP OUT OF THE GRIDS. BIGGEST QUESTION IS WHETHER THE SHALLOW COLD AIR MASS WILL BE ABLE TO MIX OUT ANY TODAY. GIVEN STRATUS IMMEDIATELY BEHIND FRONT... EXPECT THAT MIXING WILL BE DIFFICULT TODAY. BETTER YET SHOULD SEE WINDS SLOWLY VEER THROUGH THE DAY IN RESPONSE TO STRONG HEIGHT FALLS WITH APPROACHING UPPER LOW. MADE APPROPRIATE CHANGES TO TEMPERATURE GRIDS FOR THE ABOVE REASONING WITH A TIGHT GRADIENT NEAR THE EASTERN EDGE OF THE CAPROCK. FOR TONIGHT...WILL GO MOVEMENT NEUTRAL WITH THE FRONT AS AM UNSURE WHETHER HEIGHT FALLS AND VEERING WINDS ABOVE THE COLD AIR WILL OUTWEIGH DIURNAL TENDENCY TO SEE THE DENSITY CURRENT BEGIN PROPAGATING SWD AGAIN. BEST POTENTIAL FOR NORTHWARD MOVEMENT OF THE FRONT WILL BE WEDNESDAY AS STRONG WEST WINDS KICK IN. .LONG TERM... CHALLENGING FORECAST ON TAP FOR THE WEDNESDAY THROUGH THURSDAY TIME FRAME. VERY STRONG UPPER LEVEL POSITIVE TILTED LOW WILL MOVE ACROSS THE FOUR CORNERS REGION AND EJECT NORTH OF THE TEXAS SOUTH PLAINS BY WEDNESDAY LATE WEDNESDAY AFTERNOON. ETA/GFS SOLUTIONS NOW IN BETTER AGREEMENT FOR STRONG WINDS BEGINNING AFTER 12Z WEDNESDAY AND CONTINUING INTO THE 21-23Z TIME FRAME. WILL ADD A WIND ADVISORY TO THE SOUTHWEST AND SOUTH CENTRAL 6 COUNTIES FOR THE FOLLOWING REASON. 700MB HEIGHT CHANGE FROM AMA TO MAF PROGGED TO BE IN THE 70 TO 80M RANGE WITH CORRESPONDING MAXIMUM VORTICITY LOBE MOVING ACROSS THE CAPROCK REGIONS THROUGH 20Z WEDNESDAY. THIS FACTORED WITH A GOOD SURFACE PRESSURE GRADIENT WILL WORK IN TANDEM TO PRODUCE STRONG W TO WSW FLOW ACROSS MUCH OF THE REGION. DO BELIEVE ADVISORY WINDS OF 30 TO 40 MPH SUSTAINED A GOOD BET...AT LEAST OVER THE ABOVE MENTIONED REGIONS. GUSTS IN THE 50 TO 55 MPH RANGE ALSO POSSIBLE. SHALLOW COLD FRONT WILL MAKE THE ONGOING FORECAST QUITE TRICKY TO SAY THE LEAST. ALL MODEL SOLUTIONS ARE OFF PERTAINING TO COLD AIR PROGRESSION...INTENSITY AND DEPTH. DO BELIEVE THE STRONG DOWNSLOPE FLOW AND MIXING SHOULD BE ENOUGH TO SCOUR COLD AIR NORTH AND NORTHEAST OF THE CWA BY WEDNESDAY AFTERNOON. UNCERTAINTIES DO REMAIN AS TO HOW FAR SOUTH COLD AIR CAN PENETRATE TUESDAY NIGHT. IF IT DOES PUSH FURTHER SOUTH...AS SEEN A WEEK AGO...WINDS MAY NOT GET AS HIGH...ESPECIALLY POINTS OFF THE CAPROCK. AS THE UPPER LEVEL SYSTEM BYPASSES THE REGION LATE WEDNESDAY...CAA WILL QUICKLY WRAP IN BEHIND THE SYSTEM. WILL STILL KEEP COLD FRONT AND EDGE OF ARCTIC AIR MOVING THROUGH THE CWA LATE WEDNESDAY NIGHT AND THURSDAY MORNING. ALONG THE FRONT...THERE COULD BE LOW LEVEL FORCING IN PLACE. DID LIMIT POPS WEDNESDAY DUE TO MAXIMUM DOWNSLOPE COMPONENT OVER ALL OF THE CENTRAL AND WESTERN COUNTIES. THE EXTREME NORTHEAST HAS THE BEST CHANCE FOR LIGHT RAIN SHOWERS...CHANGING TO SOME LIGHT SNOW THROUGH 12Z THURSDAY. NO ACCUMULATIONS EXPECTED AT THIS TIME. THURSDAY TEMP FORECAST MUCH LOWER THAN GUIDANCE AS SHALLOW COLD AIR-MASSES NOT DEPICTED WELL IN MODELS DUE TO LIMITED RESOLUTION PARAMETERS. TEMPS FORECASTED IN THE LOWER TO MIDDLE 30S FOR HIGHS. DO EXPECT STRATUS DECK TO REMAIN IN PLACE...HELPING TO KEEP LOW LEVEL CAA ONGOING. COLD AIR REMAINS ENTRENCHED OVER THE CWA THROUGH THE WEEKEND WITH LOW LEVEL UPSLOPE FLOW DEVELOPING. KEPT TEMPS BELOW GUIDANCE THROUGH SUNDAY AND MONDAY. TEMPERATURE MODERATION POSSIBLE BY NEXT TUESDAY WITH ANOTHER UPPER LEVEL STORM LURKING OUT WEST FOR THE EXTENDED LONG RANGE PERIOD. MADE MINOR CHANGES TO SHORT AND MEDIUM RANGE GRIDS...NO CHANGES TO THE LONG TERM. THANKS TO AMA AND MAF FOR COORDINATION. WIDELSKI && .PRELIMINARY POINT TEMPS/POPS... FRIONA 65 39 50 18 / 0 20 20 20 TULIA 65 39 52 21 / 0 20 20 20 PLAINVIEW 65 43 55 22 / 0 20 20 20 LEVELLAND 69 45 59 23 / 0 20 10 10 LUBBOCK 67 45 59 23 / 0 20 10 10 BROWNFIELD 70 45 62 25 / 0 20 10 10 CHILDRESS 44 41 55 24 / 0 20 20 20 SPUR 62 47 60 27 / 0 20 20 10 ASPERMONT 65 49 62 30 / 0 20 20 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07/17 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 405 AM CST TUE JAN 11 2005 .SHORT-TERM (TUESDAY THROUGH WEDNESDAY)...MORNING SFC OBS SHOWING AREAS OF DENSE FOG ONCE AGAIN FROM VCT TO ALI AND ALONG THE COAST WITH LOW CLOUDS SPREADING WESTWARD TO HBV AND COT. SFC WINDS ARE DECOUPLING IN MANY LOCATIONS...HOWEVER CRP VAD WIND PROFILE AND LATEST RUC 925MB ANALYSIS SUGGEST THAT WINDS IN THE 1-3KFT LAYER ARE AROUND 30KTS. THIS IS KEEPING BL TURBULENT ENOUGH TO PREVENT WIDESPREAD DENSE FOG AT THE MOMENT. WILL KEEP DENSE FOG ADVISORY OVER THE EAST GOING FOR THE TIME BEING UNLESS VISBYS IMPROVE SIGNIFICANTLY. ANOTHER VERY WARM DAY IN STORE FOR SOUTH TEXAS AS DISTURBANCE MOVES INTO THE SOUTHWEST US AND SOUTHERLY WINDS INCREASE. H85 WINDS WILL BECOME SOUTHERLY AND INCREASE TO 20-25KTS LATE THIS AFTERNOON AND THIS SHOULD ALLOW FOR TEMPS TO CLIMB INTO THE MID/UPPER 80S OUT WEST UNDER P/C SKIES...LOWER 80S EAST. MAY SEE AN ISOLATED SHOWER OUT OVER THE WATER AGAIN THIS AFTERNOON. LLJ REALLY BEGINS TO CRANK LATER TONIGHT INCREASING TO AROUND 50KTS AS SFC LOW DEEPENS OVER SW KANSAS. BL SHOULD BE SUFFICIENTLY MIXED AND SFC WINDS HIGH ENOUGH TOMORROW NIGHT TO PRECLUDE THE MENTION OF FOG. WILL SEE BREEZY/WINDY CONDITIONS OVER MOST OF THE AREA ON WEDNESDAY WITH SCA CONDITIONS OVER THE WATERS. SLIGHTLY COOLER WATER TEMPS MAY KEEP WINDS OVER THE BAYS DOWN IN SCEC RANGE. TEMPS AGAIN ON WED WILL BE VERY WARM WITH LOW/MID 80S EAST...MID/UPPER 80S WEST. WILL ALSO INTRODUCE SLIGHT CHANCE POPS OVER THE EAST FOR WED AFTN AS MID-LEVEL CAPPING BEGINS TO ERODE WITH APPROACHING S/W AND COLD FRONT. MOISTURE/INSTABILITY WILL BE SUFFICIENT TO GENERATE PRE FRONTAL CONVECTION IF ANY TYPE OF LOCAL FORCING CAN BE ACHIEVED. RECORDS OF NOTE (TODAY AND TOMORROW) LOCATION RECORD HIGH YEAR CORPUS CHRISTI 84 1980 VICTORIA 82 1923 CORPUS CHRISTI 82 1972 VICTORIA 84 1923 && .LONG-TERM (WEDNESDAY NIGHT THROUGH MONDAY)...THE UKMET/ECMWF/CAN MODELS ARE SLIGHTLY SLOWER THAN THE GFS WITH SWINGING THE SHORT WAVE TROUGH INTO THE SOUTHERN PLAINS 00Z THURSDAY...LOCATED OVER WEST TEXAS. WITH SLOWER ARRIVAL OF COLD FRONT...PRECIP CHANCES WILL REMAIN OVER SOUTH TEXAS ESPECIALLY EASTERN AREAS WEDNESDAY NIGHT. THE COLD FRONT WILL BE THROUGH THE OFFSHORE WATERS BY 12Z THURSDAY. STRONG ONSHORE FLOW WEDNESDAY NIGHT OVER THE GULF WATERS WILL GIVE WAY TO STRONG OFFSHORE FLOW THURSDAY. ARCTIC AIRMASS WILL BE SET TO PLUNGE SOUTHWARD AS THE UPPER TROUGH AXIS MOVES INTO THE PLAINS THURSDAY/FRIDAY. MODELS HAVE SLOWED DOWN THE ADVANCE OF THE ARCTIC AIRMASS INTO THE SOUTHERN PLAINS UNTIL SATURDAY. SOURCE REGION OF THIS ARCTIC AIRMASS IS OVER ALASKA AT THIS TIME WITH READINGS OF -40 TO -50 F. DENSE COLD AIR SHOULD NOT HAVE A PROBLEM MOVING SOUTH AS UPPER TROUGH AXIS MOVES INTO CENTRAL PORTION OF NORTH AMERICA. WILL CONTINUE FORECAST TEMPS AROUND 10 DEGREES BELOW GUIDANCE FOR FRIDAY INTO THE WEEKEND. LATE SATURDAY ISENTROPIC UPGLIDE BEGINS TO INCREASE AND EXPECT CLOUDS TO ENVELOP SOUTH TEXAS AND STAY THROUGH MONDAY. MAY SEE SOME LIGHT PRECIP BY MONDAY BUT WILL HOLD OFF ON INSERTING RAIN CHANCES AT THIS TIME. STRONG OFFSHORE FLOW WILL PERSIST FROM FRIDAY THROUGH MONDAY FOR THE OFFSHORE WATERS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 83 65 84 56 67 / 05 10 20 30 00 VICTORIA 80 63 81 53 64 / 05 10 20 30 00 LAREDO 87 63 88 52 64 / 05 05 05 10 00 ALICE 85 63 86 54 65 / 05 10 10 20 00 ROCKPORT 76 67 79 56 66 / 05 10 20 30 00 COTULLA 85 61 87 49 64 / 05 05 05 10 00 && .CRP WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY TXZ231>234-241>247 UNTIL 9 AM. && $$ 91/DUNN...SHORT-TERM 89/TMT...LONG-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 333 AM CST TUE JAN 11 2005 .DISCUSSION... COLD FRONT IN SOUTHWESTERN OKLAHOMA WILL EASE ACROSS THE RED RIVER THIS MORNING INTO OUR NORTHWESTERN ZONES...BEFORE PULLING BACK TONIGHT. DESPITE THE LACK OF UPPER SUPPORT FEEL THE RUC HAS A GOOD HANDLE ON THIS SHALLOW AIRMASS AND HAVE ADJUSTED OUR FORECAST ACCORDINGLY. THIS HAS MADE THE FORECAST RATHER TRICKY IN THAT REGION WITH A STRONG TEMPERATURE GRADIENT DURING THE DAY TODAY. DO NOT THINK IT WILL MAKE IT INTO THE DALLAS...FORT WORTH AREA...BUT WILL GET EXTREMELY CLOSE TO THE NORTHWEST BEFORE BECOMING STATIONARY. THE WEST COAST UPPER LOW WILL OPEN AND SPEED EASTWARD OVER THE NEXT 48 HOURS...BRINGING US A CHANCE OF THUNDERSTORMS WEDNESDAY. SOME OF THE STORMS COULD APPROACH SEVERE LIMITS IN THE EAST LATE IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...THE COLD AIRMASS OVER THE CENTRAL PLAINS WILL PUSH SOUTHWARD...BRINGING US CHILLY TEMPS THROUGH THE WEEKEND...WELL BELOW GUIDANCE. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 60 72 40 / 10 10 50 30 WACO, TX 75 62 73 44 / 10 10 50 30 PARIS, TX 72 59 72 41 / 10 10 50 50 DENTON, TX 59 54 71 38 / 10 10 50 30 MCKINNEY, TX 70 59 73 40 / 10 10 50 40 DALLAS, TX 73 60 73 41 / 10 10 50 30 TERRELL, TX 74 61 73 42 / 10 10 50 30 CORSICANA, TX 74 62 74 44 / 10 10 50 30 TEMPLE, TX 75 62 74 45 / 10 10 30 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 42 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 408 AM CST TUE JAN 11 2005 .DISCUSSION...FORECAST FOCUS IS ON RESOLVING PRECIPITATION CHANCES AND TYPE TODAY AND WEDNESDAY...THEN ARCTIC OUTBREAK. IN THE SHORT TERM...DRY AIR AT THE SURFACE HELD OFF PCPN IN THE CWA OVERNIGHT EXCEPT IN THE FAR SE CORNER. RRQ OF EXITING 100- 120KT UPR JET STREAK ENHANCED LIFT OVER RGN AND THO MAINLY ISENTROPICALLY DRIVEN PCPN IN SRN WI...RUC ANALYSIS AND WATER VAPOR LOOPS INDICATED A SHRT WAVE CROSSING CNTRL IL THAT ADDED A DYNAMIC COMPONENT AFFECTING LOCATIONS TO OUR SOUTH. CONTINUED WEAK WAA TODAY WILL KEEP SCT FLURRIES AND PATCHY -ZL IN FCST...THO MOST OF THE DAY WILL BE DRY AS ISENTROPIC LIFT DIMINISHES FOR A TIME. FLOW BEGINS TO BACK TO THE SOUTH TONIGHT IN ADVANCE OF SYSTEM FOR WED/WED NGT. TEMP PROFILES SUGGEST A PERIOD OF FZRA BEFORE CHANGING OVER TO ALL RAIN...BUT WILL NOT ISSUE HEADLINE AND ALLOW NEXT SHIFT TO GET A BETTER HANDLE ON VERTICAL TEMP PROFILE. ALL MODELS AGREE WITH WED SYSTEM TRACKING OVER CWA WED EVE WITH ARCTIC PLUNGE OF AIR BEHIND THURSDAY. QPF ACROSS CWA IN THE 3/4 IN TO 1 INCH RANGE. SOME DIFFERENCES IN AMOUNT OF WARMTH AHEAD OF LOW... BUT ENOUGH LIQUID PCPN TO BE CONCERNED WITH POTENTIAL AREAL FLOODING OF LOW SPOTS AS STORM DRAINS AND CULVERTS ARE CLOGGED WITH SNOW AND FROZEN GROUND WILL NOT SOAK UP ANY RAIN. ALSO...IF SURFACE TEMPS DO WARM AHEAD OF LOW...POTENTIAL BREAK UP OF ICE ON AREA RIVERS COULD LEAD TO DAMMING. HAVE ISSUED FLOOD WATCH FOR WED AFTN/NIGHT FOR ALL OF CWA. BECOMES VERY WINDY TOWARDS THURSDAY MORNING WITH ARCTIC AIR MASS OVERTAKING CWA. GFS H8 TEMPS STILL GETTING DOWN TO -28C ON FRIDAY... WITH ETA ONLY A BIT WARMER AT -22C. THE BITTER COLD TEMPS/WIND CHILLS WILL CONTINUE TO BE HIGHLIGHTED IN HWO. && .MKX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH WED AFTERNOON/NIGHT FOR ALL ZONES. $$ REM wi AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE CHICAGO IL 520 AM CST TUE JAN 11 2005 .DISCUSSION WILL BE UPDATING THE ZONES TO CLEAR UP SNFL AMOUNTS ACROSS THE NRN ZONES. PER UPSTREAM 88DS IN IA, THE POTPOURRI OF WEATHER SHOULD TAPER DOWN AROUND 10 AM LEAVING LIGHT SCATTERED ACTIVITY THROUGH THE REST OF THE DAY. LATEST RUC TEMP VALUES CONTINUE THE TREND FOR A ...SLOW...UPWARD TREND TO TODAY'S SFC TEMPS...HANGING ON TO NEAR 32F TEMPS ACROSS THE NW ZONES. WILL NEED TO KEEP AN EYE ON THINGS FOR TONIGHT AS FZDZ COULD BE AN ISSUE NORTH OF I-88. UPDATED ZFP WILL BE OUT SOON. ...PREV DISC BELOW... WILL BE EXTENDING THE END TIME FOR THE CURRENT ADVISORY TO END AT 18 UTC. ONLY NWP CLOSEST TO CURRENT SFC/88D TRENDS IS THE RUC20 AS THE ETA IS TOO COLD AT THE SFC THRU H925. AN INVERTED SFC TROUGH ACROSS THE CWA, CLEARLY RESOLVED BY THE NRN IL/IN MESONET STATIONS, HAS PLAYED HAVOC WITH THE SFC TEMPS AND AS A RESULT PRECIP TYPES/DURATION. THE TROUGH HAS SLIPPED SOUTH AND EAST OVER THE PAST 8 HRS INHIBITING SFC TEMP WARM UP. NORTH OF THE TROUGH AND APPARENTLY ALONG THE H85 STRENGTHENING BAROLCINIC AND CONFLUENCE ZONE, A PERSISTENT MESOBAND OF SN CONTINUES THIS MORNING FOR LOCATIONS NORTH OF I88. THUS FAR UNDER THAT BAND 5 INCHES OF NEW SNOW HAS BEEN REPORTED NEAR GURNEE, 4 AT LAKE VILLA AND 3.5 INCHES 7-8 MILES WNW OF RFD. IT APPEARS THE THAT BAND WILL HOLD TOGETHER BETWEEN RFD TO UGN FOR ANOTHER FEW HRS. WOULD NOT BE SURPRISED TO SEE LOCALIZED 6/7" AMOUNTS BASED ON THE AFOREMENTION REPORTS. WILL NOT BE ISSUING A WARNING GIVEN THE ISOLATED NATURE RESIDING WITHIN THE CURRENT WINTER WEATHER ADVISORY. THE BULK OF THE STEADIER/HEAVIER PRECIP IS NOW EXPECTED TO TAPER OFF NEAR SUNRISE...WITH SCATTERED PRECIP CONTINUING THRU THE DAY WITH PATCHY/AREAS OF FG/BR. TEMPS SHOULD SLOWLY WARM BUT HAVE HELD MIXED WORDING ACROSS THE FAR NW COUNTIES THROUGH THE DAY AS THAT AREA WILL TAKE THE LONGEST TO WARM ABOUT 32F. FROM THERE...HAVE FOLLOWED THE ETA FROM TONIGHT THRU THR MORNING AS THE LATEST GFS APPEARS TOO FAR NORTH WITH ITS SFC FEATURES VS. THE POSITION OF THE LOW-MIDLVL BAROCLINIC ZONE. TONIGHT NW IN STANDS TO RECEIVE THE LARGEST PRECIP AMOUNTS AS THE NEXT S/WV PASSES ACROSS THE REGION. HAVE ADDED AREAS OF FG FOR TONIGHT THRU WED NIGHT. WED AFTERNOON INTO WED NIGHT WILL SEE THE ARRIVAL OF THE LAST IN THE RECENT SERIES OF S/WV TROUGHS. MODEL QPFS PRODUCE 3/4 TO 1.5 INCHES OF ADDITIONAL RAINFALL ACROSS THE CWA. WILL HOIST AN AREAL FLOOD WATCH FOR THE ENTIRE CWA VALID 00 UTC THR TO 12 UTC THR AS RUNOFF ATOP THE RESIDUAL SNOW PACK, BLOCKED DRAINS/CULVERTS, AND/OR THE CURRENT HIGH SOIL MOISTURE COULD CAUSE LOW SPOTS TO FILL WITH WATER. SHOULD SEE A CHANGE OVER TO SN LATE WED NIGHT BEHIND A STRONG COLD FRONT. AT THIS TIME ACCUMULATIONS APPEAR LIGHT. -SHSN LINGER INTO THRU MORNING WITH TEMPS FALLING THROUGH THE DAY. LEFT THE COLD EXTEND PERIODS IN TACT THIS GO AROUND. && .AVIATION... CIGS HAVE BEEN LOWERING OVERNIGHT AS WINTRY MIX OF PCPN CONTS. WILL EXPECT CIGS AT IFR AND OCNL LIFR WITH VSBY AT MVFR IN PCPN AND FOG. VSBY LOWERING AS DWPTS RISE AOA 32 TO MELT SNOW LATE THIS AFTN. OVERNIGHT SHUD BE PRETTY STABLE AT IFR OR LIFR. WINDS SHUD CONT FROM THE EAST 5 TO 10 MPH THRU 06Z TNGT...VEERING MORE TO SE TOWARD TUESDAY MRNG. && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...WINTER WX ADVSRY UNTIL NOON TUES ROUGHLY N STREATOR-KVPZ LINE. FLOOD WATCH WEDNESDAY NIGHT ALL CWA. .IN...WINTER WX ADVSRY UNTIL NOON TUES FOR LAKE/PORTER COUNTIES. .LK MI... $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 640 AM EST TUE JAN 11 2005 .AVIATION... FEW CHANGES TO GOING TERMINAL FORECAST. KSBN NOW ALL RAIN AND STOPPED FZRA AS SOUNDING SHOULD CONTINUE TO SLOWLY WARM. PRIMARILY LIFR CIGS THROUGHOUT THE DAY. THEN BETTER LIFT/MOISTURE WITH I300 SURFACE LATER TONIGHT AND BRING IN MODERATE RAIN WITH SOME DEEPER MIXING...BROUGHT CIGS UP A BIT...BUT STILL IFR. && .SHORT TERM... TODAY AND TONIGHT INITIAL WAVE/I295 CROSS ISALLOBARIC FLOW GENERATING ADVISORY LEVEL PRECIP ACROSS NORTHERN THIRD OF CWA AS FAIRLY FAST MOVING. IN MICHIGAN CURRENTLY BEST LIFT AND DYNAMIC/EVAPORATIVE COOLING WITH 900-700 MB INITIAL DRY LAYER ENOUGH TO KEEP PROFILE COLD ENOUGH FOR SNOW WITH ONE REPORT OF NEAR 2 INCHES ALREADY NEAR STATE LINE. HAVE CHANGED HEADLINE TO WINTER WEATHER ADVISORY FOR MICHIGAN COUNTIES...FURTHER SOUTH WILL CONTINUE WITH FREEZING RAIN ADVISORY WITH A MENTION OF BRIEF PL/SN MIX. BUT PRIMARILY ZR AS PTYPE. IN WAKE OF WAVE LATER THIS AM...IN MICHIGAN SHOULD SEE COLUMN REVERT TO FZRA PROFILE PER RUC/GFS SOUNDINGS WITH LACK OF SIGNIFICANT LIFT/COOLING. KEPT MAX TEMPS CLOSER TO A BIT BELOW COOLER MAV GUIDANCE WITH SNOW/ICE COVER AND LOW LEVEL THERMAL BAROCLINIC ZONE SETTING UP FURTHER SOUTH THAN ETA. PREFERENCE LIES MORE TOWARD CONSISTENT GFS WITH THIS RESPECT. LATER TONIGHT ANOTHER STRONGER SHOT OF I300 LIFT WITH GOOD MOISTURE TAP OF 5-6.5 G/KG ACROSS LOWER OHIO VALLEY AND HAVE BUMPED POPS TO 100 PERCENT CATEGORICAL BUT NO CHANCE TO BEAT MAV WITH 97-100 POPS. FOCUS SHIFTS LATER TONIGHT WITH QPF/WARMING TEMPS TO START OF RUNOFF/FLOOD ISSUES WITH WIDESPREAD SWE OF 1-2 INCHES PLUS ACROSS CWA AND ANTICIPATE WIDESPREAD BASIN AVERAGE RAINFALL TOTALS OF 0.5-1 INCHES BY WEDNESDAY NIGHT. THUS HAVE ISSUES FLOOD WATCH FOR POTENTIALLY SIGNIFICANT FLOODING LATE TONIGHT AND CONTINUE THROUGH WEDNESDAY NIGHT. && .LONG TERM... WEDNESDAY THROUGH MONDAY MAJOR PATTERN CHANGE WILL TAKE PLACE IN THE EARLY PART OF THE EXTENDED PERIOD WITH A RETURN TO BELOW NORMAL TEMPS BY THURSDAY NIGHT. PATTERN...THE NEGATIVE PNA PATTERN OF THE PAST FEW WEEKS WILL FLIP INTO A MORE TYPICAL MID WINTER POSITIVE PNA PATTERN BY THE END OF THIS WEEK. GFS ENSEMBLE MEAN PNA INDEX FORECAST SHOWING HIGH CONFIDENCE IN THIS PATTERN ADJUSTMENT. A STRONG PACIFIC CUTOFF LOW NOW MOVING ONSHORE INTO CALIFORNIA WILL EJECT THROUGH THE SOUTHWEST US AND INTO THE PLAINS BY MIDWEEK. THIS SYSTEM WILL PHASE WITH A STRONG NORTHERN STREAM SHORTWAVE DROPPING SOUTHEAST THROUGH THE CANADIAN PRAIRIES WITH A RAPIDLY DEEPENING SURFACE LOW CUTTING THROUGH THE LAKES WED NGT AND THURS. THE POLAR VORTEX WILL DROP INTO PLACE BEHIND THIS SYSTEM AND TAKE UP ITS TYPICAL MID WINTER RESIDENCE NEAR HUDSON BAY BY THE END OF THE WEEK. GFS ENSEMBLE MEAN FORECAST OF THE NAO AND AO INDICES INDICATING A GENERAL TREND TOWARDS A MORE NEGATIVE PHASE OF THE NAO BY LATE JANUARY SUGGESTING THAT THE COLDER PATTERN MAY BEGIN TO LOCK INTO THE EASTERN HALF OF THE CONUS. DEEP SOUTH FLOW AHEAD OF THE PACIFIC SYSTEM WILL DEVELOP ON WED. 925MB TEMPS SOAR TO +12C WHICH WOULD SUPPORT UPPER 50S EVEN WITH PURELY MOIST ADIABATIC MIXING. WARM SECTOR WILL BE MOIST AND AMPLE CLOUD COVER SHOULD KEEP TEMPS ON THE MORE CONSERVATIVE SIDE OF GUIDANCE NUMBERS WITH LOW 50S NORTH AND MID 50S SOUTH. INGREDIENTS COMING TOGETHER FOR A HEALTHY PERIOD OF RAIN WED NIGHT. PLUME OF ANOMALOUSLY MOIST AIR ADVECTS INTO THE CWA WITH PWATS OF OVER 1 INCH. LARGE SCALE LIFT WILL INCREASE OVERNIGHT WITH ADVANCING MID LEVEL TROUGH AND ASSOCIATED JET DYNAMICS. THIS WILL COMBINE WITH STRONG LOW LEVEL FRONTOGENETICAL FORCING TO PRODUCE A BAND OF DEEP LIFT ALONG THE SURFACE FRONT. ENOUGH DYNAMICS AND DEEP MOISTURE TO CONTINUE WITH MENTION OF ISOLATED THUNDER WITH TOTAL TOTALS AROUND 50. STRONG FROPA THURSDAY MORNING. GFS/CANADIAN GEM/ETA IN GOOD AGREEMENT WITH TIMING OF SURFACE FRONT WITH THE FRONT BISECTING THE CWA AT 12Z THURS. ECMWF A LITTLE SLOWER AND DISCOUNTED FOR NOW. THIS MAKES THE MAX TEMP FORECAST INTERESTING FOR THURSDAY AS JUST A FEW HOURS IN TIMING WILL MAKE A 20+F DIFFERENCE. WILL START TEMPS OFF IN THE UPPER 40S EAST TO MID/UPPER 30S WEST WITH FALLING TEMPS ALL DAY IN VERY STRONG CAA REGIME. BEST FORCING SHIFTS QUICKLY EAST OF THE CWA DURING THE MORNING. WILL CARRY LIKELY POPS EARLY IN THE EAST THEN TAPER POPS BACK TO CHANCE WITH SKIES BECOMING PARTLY CLOUDY BY AFTERNOON WITH SURFACE RIDGE BUILDING IN BEHIND SURFACE FRONT. THURSDAY NIGHT THROUGH THE WEEKEND A COLD ARCTIC AIRMASS WILL DOMINATE THE CWA. NO WEATHER TO WORRY ABOUT SYNOPTICALLY...SO OUR ATTENTION TURNS TO THE MESOSCALE. GFS SHOWING 850MB TEMPS IN THE -20C TO -24C RANGE POURING ACROSS LAKE MICHIGAN THURS NGT THROUGH SAT NGT. SYNOPTIC PATTERN WOULD SUGGEST WESTERLY FLOW WITH RELATIVELY LOW INVERSION HEIGHTS AND VERY LIMITED AMBIENT MOISTURE. LAKE EFFECT BANDS WILL HAVE TO OVERCOME SHORT FETCH AND SPARSE SYNOPTIC MOISTURE AVAILABILITY. HAVING SAID THAT...WEAK SHORTWAVES AND SURFACE TROUGHS ROTATING THROUGH THE MEAN NW FLOW ALOFT CAN SIGNIFICANTLY IMPROVE THE LAKE EFFECT SETUP AT TIMES IN THIS KIND OF PATTERN. THESE SHORTWAVES CANNOT BE TIMED THIS FAR IN ADVANCE. FOR NOW WILL KEEP CHANCE POPS IN COUNTIES FAVORED BY WESTERLY FLOW THROUGH THE FIRST HALF OF THE WEEKEND. SUB ZERO LOW TEMPS WILL BE POSSIBLE ON NIGHTS WHEN SKIES CLEAR AND WINDS ARE CALM. BEST CHANCE APPEARS TO BE FRIDAY NIGHT INLAND AWAY FROM LAKE EFFECT CLOUDS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FREEZING RAIN ADVISORY THROUGH NOON FOR ZONES INZ003>009...INZ012...INZ014...INZ016. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. MI...WINTER WEATHER ADVISORY THROUGH NOON FOR ZONES MIZ077>081. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. OH...FREEZING RAIN ADVISORY THROUGH NOON FOR ZONES OHZ001>002...OHZ004>005. FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. && $$ SHORT TERM/AVIATION...MURPHY LONG TERM...HITCHCOCK in AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 659 AM EST TUE JAN 11 2005 CORRECTED HEADING BELOW FOR AVIATION .AVIATION... EXCEPT FOR OCCASIONAL MVFR TO EVEN VFR CEILINGS FNT/MBS TODAY...RATHER WIDESPREAD IFR TO LOCAL LIFR CEILINGS THROUGH TONIGHT...WITH LOTS OF MOISTURE TO WORK WITH. DYNAMICS THIS MORNING...LARGELY AFFECTING SOUTHERN SITES...DTW/DET...INCLUDING FRONTOGENESIS AND OMEGA LIFT...WHERE IFR VISIBILITY SNOW IS LARGELY CONFINED. IN THE SOUTH...EXPECT IFR VISIBILITIES TO PREVAIL THROUGH TONIGHT...WITH PRECIPITATION TYPE MIXING WITH SLEET THEN OVER TO ALL RAIN BY DARK TONIGHT. IN FNT/MBS...EXPECT IFR VISIBILITIES TO DEVELOP THIS EVENING WITH FREEZING RAIN OR FREEZING DRIZZLE CHANGING OVER TO ALL RAIN OVERNIGHT AS TEMPERATURES MODERATE. && .PREV DISCUSSION...ISSUED 342 AM EST TUESDAY AN EXTREMELY COMPLEX EVENT UNFOLDING WITH A VARIETY OF PRECIP TYPE ISSUES THE NEXT 12-18 HOURS TO BE FOLLOWED BY A STRONG LINE OF CONVECTION AND HEAVY RAINFALL POTENTIAL...WHICH WILL LEAD TO THE ARCTIC BLAST THURSDAY INTO THE UPCOMING WEEKEND. WATER VAPOR AND RADAR IMAGERY IMAGERY SHOW SEVERAL PLAYERS WORKING TOGETHER FOR THIS NARROW, YET INTENSE, REGION OF PRECIPITATION. SHORT WAVE, ALBEIT BECOMING MORE STRUNG OUT, WAS PROGRESSING ACROSS ILLINOIS/INDIANA. TO OUR NORTH A DEPARTING 130KT 300MB JET WAS AIDING IN THE LIFT PROCESS ACROSS NORTHERN INDIANA AND OUR FIRST SHOT OF WARM ADVECTION. LATEST RUC ANALYSIS SHOWS THIS NICELY WITH TIGHTENING THERMAL GRADIENT IN THE 800-700MB LAYER AND 2D-FGEN FORCING WAS VERY IMPRESSIVE ACROSS THE MICHIGAN STATE LINE. HOWEVER, ANOTHER REGION OF THERMALLY INDUCED FGEN WAS WEAKENING TO OUR NORTH AS THERMAL STRUCTURE IS EXPECTED TO WEAKEN TOWARD 12Z. TAKING THE LATEST RUC, REGION OF FGEN AND OMEGA WILL PERSIST ACROSS OUR SOUTHERN 4 COUNTIES THROUGH THIS MORNING AND WEAKEN DURING THE AFTERNOON AS WAVE DEPARTS TO OUR EAST. AS THE SURFACE, 1012MB LOW WAS NEAR KSTL WITH WARM FRONT EXTENDING EAST INTO KENTUCKY WITH 1027MB HIGH JUST EAST OF GEORGIAN BAY. TODAY... WE WILL CONTINUE WITH OUR ADVISORY FOR THOSE SOUTHERN 4 COUNTIES AND EXPAND IT A TIER NORTH THIS MORNING AS THEY WILL REMAIN NEAR THE FGEN FORCING AND FAVORABLE POSITION OF OUR DEPARTING JET THROUGH THE REMAINDER OF THE MORNING HOURS. MODELS ARE FAIRLY SIMILAR ON THIS SITUATION BUT DISAGREE WITH SUBTLE, YET SIGNIFICANT, TEMPERATURE PROFILES. SOME ABOVE 0C TEMPS @ 925MB WERE ATTEMPTING TO MOVE INTO ADG-TTF VICINITY WITH THE LATEST TAMDAR DATA FROM DTW SHOWING SIGNS OF NEAR 0C BETWEEN 800-900MBS. WITH THAT IN MIND...THINK WE WILL SEE A LITTLE MORE OF A MIX TO HOLD DOWN OUR ACCUMULATIONS SOMEWHAT BUT IT WILL BE CLOSE. WITH THIS AMOUNT OF LIFT AND UPSTREAM RADARS VERY BRIGHT THIS MORNING...WE COULD SEE ACCUMULATIONS APPROACH 6" IF WE ARE ABLE TO KEEP THE LAYERS BELOW 0C (WE HAVE 4 G/KG IN THE 850-700MB LAYER WITH IMPRESSIVE ISENTROPIC LIFT IN THIS LAYER). THIS WILL DOMINATE OUR WEATHER TODAY AS WE WILL SEE THIS SYSTEM AND DYNAMICS WEAKEN AND PASS TO OUR EAST DURING THE AFTERNOON. HOWEVER, AS WE LOSE SOME THE MID LEVEL MOISTURE (AOA 700MB), ENOUGH SHEAR IN THE PROFILE SUGGESTS SOME FREEZING DRIZZLE/FLURRIES ACROSS THE NORTH. TEMPERATURES TODAY WOULD EXPECT TO BE COOLER THAN THOSE ADVERTISED IN THE LATEST MOS NUMBERS. BASED ON TRAJECTORIES AND EXTENSIVE CLOUD SHIELD, WOULD THINK TEMPS HOLDING THE LOWER-MIDDLE 30S. TONIGHT... THE POTENTIAL EXISTS FOR ANOTHER HEADLINE ACROSS THE NORTHERN HALF OF OUR CWA BUT THIS WILL BE REFINED WITH THE UPCOMING DAY SHIFT. LATEST GUIDANCE SUGGESTS THE NEXT BIG SURGE OF WARM THETA-E ADVECTION TO OCCUR TOWARD 06Z AS POWERFUL PACIFIC SYSTEM EJECTS INTO THE PLAINS. SHARP 850MB FRONT WILL SWING NORTH OVERNIGHT AND LIKELY PRODUCE SOME PRECIPITATION BEFORE THE MAIN SURFACE WARM FRONT APPROACHES. WITH THAT, WE HAVE AN ISSUE WITH NEAR SURFACE TEMPS. SOUNDINGS AND 3-HOURLY MOS VALUES SUGGEST WE COULD HAVE AN ACCUMULATING ICE EVENT UNFOLDING ACROSS THE NORTHERN HALF. THE QUESTION WILL BE TIMING OF THE WARM AIR AND THE PRECIP AMOUNTS AS USUALLY THE ETA HAS A BETTER HANDLE ON LOWER LEVEL TEMPS THAN THE GFS IN THESE TYPES OF SITUATIONS. HOWEVER, WE COULD HAVE ENOUGH LATENT HEAT RELEASE OF ANY FROZEN PRECIP (WHICH WOULD BE ON THE LIGHT SIDE INITIALLY) TO RAISE TEMPS JUST ABOVE FREEZING TO RESULT IN LITTLE OR ANY PROBLEMS. AS PREVIOUSLY MENTIONED, THIS WILL NEED TO BE MONITORED VERY CLOSELY AND WE WILL MAKE MENTION IN THE HWO. WEDNESDAY... WE FINALLY (WE HOPE) LOSE OUR PRECIP TYPE ISSUES AS SURFACE WARM FRONT RACES NORTH. VERY IMPRESSIVE WARM ADVECTION (850MB JET IN EXCESS OF 50KTS) WITH ELEVATED FACTORS SUGGESTING WE WILL NEED TO ADD IN SOME THUNDER POTENTIAL. THE INITIAL SURGE WILL OCCUR IN THE MORNING BUT WITH STILL DEEP THETA-E AIR OVERHEAD DURING THE AFTERNOON, WE WILL CONTINUE WITH LIKELY POPS THRU THE DAY. WE SHOULD LOSE OUR SNOW COVER FAIRLY QUICKLY AND EXPECT TEMPS TO CLIMB THROUGH THE 40S. WE MIGHT HAVE A FAIRLY EXTENSIVE FOG EVENT EARLY ON BUT AS WE LOSE THE SNOW COVER...VISIBILITIES WILL SLOWLY COME UP IN THE AFTERNOON. WEDNESDAY NIGHT... POWERFUL SHORT WAVE HEADS INTO THE PLAINS WITH NEAR PHASING ACROSS THE WESTERN LAKES WITH POLAR WAVE DIVING SOUTH TOWARD THE DAKOTAS OVERNIGHT. WITH VERY STRONG SOUTHERLY WINDS ALOFT TRANSPORTING PWATS IN EXCESS OF 1" AND ELEVATED STABILITY FACTORS SUGGESTIVE OF A SQUALL LINE MOVING ACROSS LATE... WE WILL NEED TO MONITOR FOR DAMAGING WIND GUSTS AND FLOODING ACROSS THE ENTIRE REGION. TEMPERATURES WILL CONTINUE TO RISE INTO THE 50S FOR MOST LOCATIONS OVERNIGHT. THURSDAY... IF TIMING WORKS OUT... WE WILL TRULY EXPERIENCE THE 4-SEASONS IN A SPAN OF 12 HOURS. LINE OF CONVECTION RACES EAST EARLY IN THE MORNING WITH 50 DEGREE TEMPS AND BY AFTERNOON (AKA 00Z)... 850MB TEMPS WILL BE APPROACHING -15C ACROSS OUR WESTERN COUNTIES WITH SOME SNOW SHOWERS FROM LAKE MICHIGAN AND ANY AVAILABLE MOISTURE LEFT IN THE ATMOSPHERE. WITH SUCH A STRONG FROPA...ANOTHER ROUND OF DAMAGING WIND GUSTS IS POSSIBLE AS MIXING LAYER HEIGHTS QUICKLY CLIMB AND NOT TO MENTION THE STRONG DECENT. REMAINDER OF THE FORECAST LOOKS IN GOOD SHAPE (AND QUITE COLD). ANOTHER HEADLINE MAY BE NEEDED...IN THE FORM A WIND CHILL ADVISORY. WITH TEMPERATURES INTO THE LOWER SINGLE DIGITS AND WINDS STILL AROUND 15 KTS...WIND CHILL READINGS FALL TO DANGEROUSLY LOW -20F. THANKS FOR THE COLLABORATION GRR, IWX AND APX! && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...WINTER WEATHER ADVISORY...MIZ075-076-082-083...THROUGH 2 PM TODAY. SNOW ADVISORY...MIZ068>070...UNTIL NOON .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ DWD/BGM HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 659 AM EST TUE JAN 11 2005 .UPDATE... EXCEPT FOR OCCASIONAL MVFR TO EVEN VFR CEILINGS FNT/MBS TODAY...RATHER WIDESPREAD IFR TO LOCAL LIFR CEILINGS THROUGH TONIGHT...WITH LOTS OF MOISTURE TO WORK WITH. DYNAMICS THIS MORNING...LARGELY AFFECTING SOUTHERN SITES...DTW/DET...INCLUDING FRONTOGENESIS AND OMEGA LIFT...WHERE IFR VISIBILITY SNOW IS LARGELY CONFINED. IN THE SOUTH...EXPECT IFR VISIBILITIES TO PREVAIL THROUGH TONIGHT...WITH PRECIPITATION TYPE MIXING WITH SLEET THEN OVER TO ALL RAIN BY DARK TONIGHT. IN FNT/MBS...EXPECT IFR VISIBILITIES TO DEVELOP THIS EVENING WITH FREEZING RAIN OR FREEZING DRIZZLE CHANGING OVER TO ALL RAIN OVERNIGHT AS TEMPERATURES MODERATE. && .PREV DISCUSSION...ISSUED 342 AM EST TUESDAY AN EXTREMELY COMPLEX EVENT UNFOLDING WITH A VARIETY OF PRECIP TYPE ISSUES THE NEXT 12-18 HOURS TO BE FOLLOWED BY A STRONG LINE OF CONVECTION AND HEAVY RAINFALL POTENTIAL...WHICH WILL LEAD TO THE ARCTIC BLAST THURSDAY INTO THE UPCOMING WEEKEND. WATER VAPOR AND RADAR IMAGERY IMAGERY SHOW SEVERAL PLAYERS WORKING TOGETHER FOR THIS NARROW, YET INTENSE, REGION OF PRECIPITATION. SHORT WAVE, ALBEIT BECOMING MORE STRUNG OUT, WAS PROGRESSING ACROSS ILLINOIS/INDIANA. TO OUR NORTH A DEPARTING 130KT 300MB JET WAS AIDING IN THE LIFT PROCESS ACROSS NORTHERN INDIANA AND OUR FIRST SHOT OF WARM ADVECTION. LATEST RUC ANALYSIS SHOWS THIS NICELY WITH TIGHTENING THERMAL GRADIENT IN THE 800-700MB LAYER AND 2D-FGEN FORCING WAS VERY IMPRESSIVE ACROSS THE MICHIGAN STATE LINE. HOWEVER, ANOTHER REGION OF THERMALLY INDUCED FGEN WAS WEAKENING TO OUR NORTH AS THERMAL STRUCTURE IS EXPECTED TO WEAKEN TOWARD 12Z. TAKING THE LATEST RUC, REGION OF FGEN AND OMEGA WILL PERSIST ACROSS OUR SOUTHERN 4 COUNTIES THROUGH THIS MORNING AND WEAKEN DURING THE AFTERNOON AS WAVE DEPARTS TO OUR EAST. AS THE SURFACE, 1012MB LOW WAS NEAR KSTL WITH WARM FRONT EXTENDING EAST INTO KENTUCKY WITH 1027MB HIGH JUST EAST OF GEORGIAN BAY. TODAY... WE WILL CONTINUE WITH OUR ADVISORY FOR THOSE SOUTHERN 4 COUNTIES AND EXPAND IT A TIER NORTH THIS MORNING AS THEY WILL REMAIN NEAR THE FGEN FORCING AND FAVORABLE POSITION OF OUR DEPARTING JET THROUGH THE REMAINDER OF THE MORNING HOURS. MODELS ARE FAIRLY SIMILAR ON THIS SITUATION BUT DISAGREE WITH SUBTLE, YET SIGNIFICANT, TEMPERATURE PROFILES. SOME ABOVE 0C TEMPS @ 925MB WERE ATTEMPTING TO MOVE INTO ADG-TTF VICINITY WITH THE LATEST TAMDAR DATA FROM DTW SHOWING SIGNS OF NEAR 0C BETWEEN 800-900MBS. WITH THAT IN MIND...THINK WE WILL SEE A LITTLE MORE OF A MIX TO HOLD DOWN OUR ACCUMULATIONS SOMEWHAT BUT IT WILL BE CLOSE. WITH THIS AMOUNT OF LIFT AND UPSTREAM RADARS VERY BRIGHT THIS MORNING...WE COULD SEE ACCUMULATIONS APPROACH 6" IF WE ARE ABLE TO KEEP THE LAYERS BELOW 0C (WE HAVE 4 G/KG IN THE 850-700MB LAYER WITH IMPRESSIVE ISENTROPIC LIFT IN THIS LAYER). THIS WILL DOMINATE OUR WEATHER TODAY AS WE WILL SEE THIS SYSTEM AND DYNAMICS WEAKEN AND PASS TO OUR EAST DURING THE AFTERNOON. HOWEVER, AS WE LOSE SOME THE MID LEVEL MOISTURE (AOA 700MB), ENOUGH SHEAR IN THE PROFILE SUGGESTS SOME FREEZING DRIZZLE/FLURRIES ACROSS THE NORTH. TEMPERATURES TODAY WOULD EXPECT TO BE COOLER THAN THOSE ADVERTISED IN THE LATEST MOS NUMBERS. BASED ON TRAJECTORIES AND EXTENSIVE CLOUD SHIELD, WOULD THINK TEMPS HOLDING THE LOWER-MIDDLE 30S. TONIGHT... THE POTENTIAL EXISTS FOR ANOTHER HEADLINE ACROSS THE NORTHERN HALF OF OUR CWA BUT THIS WILL BE REFINED WITH THE UPCOMING DAY SHIFT. LATEST GUIDANCE SUGGESTS THE NEXT BIG SURGE OF WARM THETA-E ADVECTION TO OCCUR TOWARD 06Z AS POWERFUL PACIFIC SYSTEM EJECTS INTO THE PLAINS. SHARP 850MB FRONT WILL SWING NORTH OVERNIGHT AND LIKELY PRODUCE SOME PRECIPITATION BEFORE THE MAIN SURFACE WARM FRONT APPROACHES. WITH THAT, WE HAVE AN ISSUE WITH NEAR SURFACE TEMPS. SOUNDINGS AND 3-HOURLY MOS VALUES SUGGEST WE COULD HAVE AN ACCUMULATING ICE EVENT UNFOLDING ACROSS THE NORTHERN HALF. THE QUESTION WILL BE TIMING OF THE WARM AIR AND THE PRECIP AMOUNTS AS USUALLY THE ETA HAS A BETTER HANDLE ON LOWER LEVEL TEMPS THAN THE GFS IN THESE TYPES OF SITUATIONS. HOWEVER, WE COULD HAVE ENOUGH LATENT HEAT RELEASE OF ANY FROZEN PRECIP (WHICH WOULD BE ON THE LIGHT SIDE INITIALLY) TO RAISE TEMPS JUST ABOVE FREEZING TO RESULT IN LITTLE OR ANY PROBLEMS. AS PREVIOUSLY MENTIONED, THIS WILL NEED TO BE MONITORED VERY CLOSELY AND WE WILL MAKE MENTION IN THE HWO. WEDNESDAY... WE FINALLY (WE HOPE) LOSE OUR PRECIP TYPE ISSUES AS SURFACE WARM FRONT RACES NORTH. VERY IMPRESSIVE WARM ADVECTION (850MB JET IN EXCESS OF 50KTS) WITH ELEVATED FACTORS SUGGESTING WE WILL NEED TO ADD IN SOME THUNDER POTENTIAL. THE INITIAL SURGE WILL OCCUR IN THE MORNING BUT WITH STILL DEEP THETA-E AIR OVERHEAD DURING THE AFTERNOON, WE WILL CONTINUE WITH LIKELY POPS THRU THE DAY. WE SHOULD LOSE OUR SNOW COVER FAIRLY QUICKLY AND EXPECT TEMPS TO CLIMB THROUGH THE 40S. WE MIGHT HAVE A FAIRLY EXTENSIVE FOG EVENT EARLY ON BUT AS WE LOSE THE SNOW COVER...VISIBILITIES WILL SLOWLY COME UP IN THE AFTERNOON. WEDNESDAY NIGHT... POWERFUL SHORT WAVE HEADS INTO THE PLAINS WITH NEAR PHASING ACROSS THE WESTERN LAKES WITH POLAR WAVE DIVING SOUTH TOWARD THE DAKOTAS OVERNIGHT. WITH VERY STRONG SOUTHERLY WINDS ALOFT TRANSPORTING PWATS IN EXCESS OF 1" AND ELEVATED STABILITY FACTORS SUGGESTIVE OF A SQUALL LINE MOVING ACROSS LATE... WE WILL NEED TO MONITOR FOR DAMAGING WIND GUSTS AND FLOODING ACROSS THE ENTIRE REGION. TEMPERATURES WILL CONTINUE TO RISE INTO THE 50S FOR MOST LOCATIONS OVERNIGHT. THURSDAY... IF TIMING WORKS OUT... WE WILL TRULY EXPERIENCE THE 4-SEASONS IN A SPAN OF 12 HOURS. LINE OF CONVECTION RACES EAST EARLY IN THE MORNING WITH 50 DEGREE TEMPS AND BY AFTERNOON (AKA 00Z)... 850MB TEMPS WILL BE APPROACHING -15C ACROSS OUR WESTERN COUNTIES WITH SOME SNOW SHOWERS FROM LAKE MICHIGAN AND ANY AVAILABLE MOISTURE LEFT IN THE ATMOSPHERE. WITH SUCH A STRONG FROPA...ANOTHER ROUND OF DAMAGING WIND GUSTS IS POSSIBLE AS MIXING LAYER HEIGHTS QUICKLY CLIMB AND NOT TO MENTION THE STRONG DECENT. REMAINDER OF THE FORECAST LOOKS IN GOOD SHAPE (AND QUITE COLD). ANOTHER HEADLINE MAY BE NEEDED...IN THE FORM A WIND CHILL ADVISORY. WITH TEMPERATURES INTO THE LOWER SINGLE DIGITS AND WINDS STILL AROUND 15 KTS...WIND CHILL READINGS FALL TO DANGEROUSLY LOW -20F. THANKS FOR THE COLLABORATION GRR, IWX AND APX! && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...WINTER WEATHER ADVISORY...MIZ075-076-082-083...THROUGH 2 PM TODAY. SNOW ADVISORY...MIZ068>070...UNTIL NOON .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ DWD/BGM HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 900 AM CST TUE JAN 11 2005 .UPDATE...VISIBILITIES ARE IMPROVING ACROSS THE AREA. HAVE LET THE DENSE FOG ADVISORY EXPIRE. WILL UPDATE ZONES TO REMOVE THE ADVISORY. OTHERWISE...FORECAST IS ON TRACK WITH NO MAJOR CHANGES AT THIS TIME. 81 && .PREVIOUS DISCUSSION... .SHORT-TERM (TUESDAY THROUGH WEDNESDAY)...MORNING SFC OBS SHOWING AREAS OF DENSE FOG ONCE AGAIN FROM VCT TO ALI AND ALONG THE COAST WITH LOW CLOUDS SPREADING WESTWARD TO HBV AND COT. SFC WINDS ARE DECOUPLING IN MANY LOCATIONS...HOWEVER CRP VAD WIND PROFILE AND LATEST RUC 925MB ANALYSIS SUGGEST THAT WINDS IN THE 1-3KFT LAYER ARE AROUND 30KTS. THIS IS KEEPING BL TURBULENT ENOUGH TO PREVENT WIDESPREAD DENSE FOG AT THE MOMENT. WILL KEEP DENSE FOG ADVISORY OVER THE EAST GOING FOR THE TIME BEING UNLESS VISBYS IMPROVE SIGNIFICANTLY. ANOTHER VERY WARM DAY IN STORE FOR SOUTH TEXAS AS DISTURBANCE MOVES INTO THE SOUTHWEST US AND SOUTHERLY WINDS INCREASE. H85 WINDS WILL BECOME SOUTHERLY AND INCREASE TO 20-25KTS LATE THIS AFTERNOON AND THIS SHOULD ALLOW FOR TEMPS TO CLIMB INTO THE MID/UPPER 80S OUT WEST UNDER P/C SKIES...LOWER 80S EAST. MAY SEE AN ISOLATED SHOWER OUT OVER THE WATER AGAIN THIS AFTERNOON. LLJ REALLY BEGINS TO CRANK LATER TONIGHT INCREASING TO AROUND 50KTS AS SFC LOW DEEPENS OVER SW KANSAS. BL SHOULD BE SUFFICIENTLY MIXED AND SFC WINDS HIGH ENOUGH TOMORROW NIGHT TO PRECLUDE THE MENTION OF FOG. WILL SEE BREEZY/WINDY CONDITIONS OVER MOST OF THE AREA ON WEDNESDAY WITH SCA CONDITIONS OVER THE WATERS. SLIGHTLY COOLER WATER TEMPS MAY KEEP WINDS OVER THE BAYS DOWN IN SCEC RANGE. TEMPS AGAIN ON WED WILL BE VERY WARM WITH LOW/MID 80S EAST...MID/UPPER 80S WEST. WILL ALSO INTRODUCE SLIGHT CHANCE POPS OVER THE EAST FOR WED AFTN AS MID-LEVEL CAPPING BEGINS TO ERODE WITH APPROACHING S/W AND COLD FRONT. MOISTURE/INSTABILITY WILL BE SUFFICIENT TO GENERATE PRE FRONTAL CONVECTION IF ANY TYPE OF LOCAL FORCING CAN BE ACHIEVED. RECORDS OF NOTE (TODAY AND TOMORROW) LOCATION RECORD HIGH YEAR CORPUS CHRISTI 84 1980 VICTORIA 82 1923 CORPUS CHRISTI 82 1972 VICTORIA 84 1923 && .LONG-TERM (WEDNESDAY NIGHT THROUGH MONDAY)...THE UKMET/ECMWF/CAN MODELS ARE SLIGHTLY SLOWER THAN THE GFS WITH SWINGING THE SHORT WAVE TROUGH INTO THE SOUTHERN PLAINS 00Z THURSDAY...LOCATED OVER WEST TEXAS. WITH SLOWER ARRIVAL OF COLD FRONT...PRECIP CHANCES WILL REMAIN OVER SOUTH TEXAS ESPECIALLY EASTERN AREAS WEDNESDAY NIGHT. THE COLD FRONT WILL BE THROUGH THE OFFSHORE WATERS BY 12Z THURSDAY. STRONG ONSHORE FLOW WEDNESDAY NIGHT OVER THE GULF WATERS WILL GIVE WAY TO STRONG OFFSHORE FLOW THURSDAY. ARCTIC AIRMASS WILL BE SET TO PLUNGE SOUTHWARD AS THE UPPER TROUGH AXIS MOVES INTO THE PLAINS THURSDAY/FRIDAY. MODELS HAVE SLOWED DOWN THE ADVANCE OF THE ARCTIC AIRMASS INTO THE SOUTHERN PLAINS UNTIL SATURDAY. SOURCE REGION OF THIS ARCTIC AIRMASS IS OVER ALASKA AT THIS TIME WITH READINGS OF -40 TO -50 F. DENSE COLD AIR SHOULD NOT HAVE A PROBLEM MOVING SOUTH AS UPPER TROUGH AXIS MOVES INTO CENTRAL PORTION OF NORTH AMERICA. WILL CONTINUE FORECAST TEMPS AROUND 10 DEGREES BELOW GUIDANCE FOR FRIDAY INTO THE WEEKEND. LATE SATURDAY ISENTROPIC UPGLIDE BEGINS TO INCREASE AND EXPECT CLOUDS TO ENVELOP SOUTH TEXAS AND STAY THROUGH MONDAY. MAY SEE SOME LIGHT PRECIP BY MONDAY BUT WILL HOLD OFF ON INSERTING RAIN CHANCES AT THIS TIME. STRONG OFFSHORE FLOW WILL PERSIST FROM FRIDAY THROUGH MONDAY FOR THE OFFSHORE WATERS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 83 65 84 56 67 / 05 10 20 30 00 VICTORIA 80 63 81 53 64 / 05 10 20 30 00 LAREDO 87 63 88 52 64 / 05 05 05 10 00 ALICE 85 63 86 54 65 / 05 10 10 20 00 ROCKPORT 76 67 79 56 66 / 05 10 20 30 00 COTULLA 85 61 87 49 64 / 05 05 05 10 00 && .CRP WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY TXZ231>234-241>247 UNTIL 9 AM. && $$ 91/DUNN...SHORT-TERM 89/TMT...LONG-TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 538 AM CST TUE JAN 11 2005 .UPDATE... HAVE ADJUSTED A FEW PARAMETERS TODAY TO REFLECT CURRENT TRENDS AND EXPECTED FRONTAL POSITION. 42 && .AVIATION... 535 AM CST 40-45KTS AT 2000FT REQUIRING LLWS MENTION EARLY THIS MORNING. FRONT IN SW OKLAHOMA HAS NOW PUSHED THROUGH VERNON. FORWARD PROGRESS SHOULD BE STUNTED WITH SW FLOW ALOFT AND THINNING POLAR AIR MASS. PROXIMITY OF FRONT WILL SERVE TO PULL WINDS WEST OF SOUTH. ST/SC ALREADY SEEN EVACUATING ON 11-3.9 IMAGERY AND FURTHER ERODING LIKELY AFTER BRIEF RADIATIONAL STRATUS NEAR DAYBREAK. EXPECT FEW/SCT MORE THAN BKN/OVC. ST/SC TO RETURN OVERNIGHT BUT IFR UNLIKELY WITH STRONG LLJ AND BL WINDS KEEPING THINGS MIXED. FRONT SHOULD RETREAT AND SOUTH WINDS WILL REMAIN THROUGH TAF PERIOD. 25 && .DISCUSSION... 333 AM CST COLD FRONT IN SOUTHWESTERN OKLAHOMA WILL EASE ACROSS THE RED RIVER THIS MORNING INTO OUR NORTHWESTERN ZONES...BEFORE PULLING BACK TONIGHT. DESPITE THE LACK OF UPPER SUPPORT FEEL THE RUC HAS A GOOD HANDLE ON THIS SHALLOW AIRMASS AND HAVE ADJUSTED OUR FORECAST ACCORDINGLY. THIS HAS MADE THE FORECAST RATHER TRICKY IN THAT REGION WITH A STRONG TEMPERATURE GRADIENT DURING THE DAY TODAY. DO NOT THINK IT WILL MAKE IT INTO THE DALLAS...FORT WORTH AREA...BUT WILL GET EXTREMELY CLOSE TO THE NORTHWEST BEFORE BECOMING STATIONARY. THE WEST COAST UPPER LOW WILL OPEN AND SPEED EASTWARD OVER THE NEXT 48 HOURS...BRINGING US A CHANCE OF THUNDERSTORMS WEDNESDAY. SOME OF THE STORMS COULD APPROACH SEVERE LIMITS IN THE EAST LATE IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...THE COLD AIRMASS OVER THE CENTRAL PLAINS WILL PUSH SOUTHWARD...BRINGING US CHILLY TEMPS THROUGH THE WEEKEND...WELL BELOW GUIDANCE. 42 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 60 72 40 / 10 10 50 30 WACO, TX 75 62 73 44 / 10 10 50 30 PARIS, TX 72 59 72 41 / 10 10 50 50 DENTON, TX 59 54 71 38 / 10 10 50 30 MCKINNEY, TX 70 59 73 40 / 10 10 50 40 DALLAS, TX 73 60 73 41 / 10 10 50 30 TERRELL, TX 74 61 73 42 / 10 10 50 30 CORSICANA, TX 74 62 74 44 / 10 10 50 30 TEMPLE, TX 75 62 74 45 / 10 10 30 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 535 AM CST TUE JAN 11 2005 .AVIATION... 535 AM CST 40-45KTS AT 2000FT REQUIRING LLWS MENTION EARLY THIS MORNING. FRONT IN SW OKLAHOMA HAS NOW PUSHED THROUGH VERNON. FORWARD PROGRESS SHOULD BE STUNTED WITH SW FLOW ALOFT AND THINNING POLAR AIR MASS. PROXIMITY OF FRONT WILL SERVE TO PULL WINDS WEST OF SOUTH. ST/SC ALREADY SEEN EVACUATING ON 11-3.9 IMAGERY AND FURTHER ERODING LIKELY AFTER BRIEF RADIATIONAL STRATUS NEAR DAYBREAK. EXPECT FEW/SCT MORE THAN BKN/OVC. ST/SC TO RETURN OVERNIGHT BUT IFR UNLIKELY WITH STRONG LLJ AND BL WINDS KEEPING THINGS MIXED. FRONT SHOULD RETREAT AND SOUTH WINDS WILL REMAIN THROUGH TAF PERIOD. 25 && .DISCUSSION... 333 AM CST COLD FRONT IN SOUTHWESTERN OKLAHOMA WILL EASE ACROSS THE RED RIVER THIS MORNING INTO OUR NORTHWESTERN ZONES...BEFORE PULLING BACK TONIGHT. DESPITE THE LACK OF UPPER SUPPORT FEEL THE RUC HAS A GOOD HANDLE ON THIS SHALLOW AIRMASS AND HAVE ADJUSTED OUR FORECAST ACCORDINGLY. THIS HAS MADE THE FORECAST RATHER TRICKY IN THAT REGION WITH A STRONG TEMPERATURE GRADIENT DURING THE DAY TODAY. DO NOT THINK IT WILL MAKE IT INTO THE DALLAS...FORT WORTH AREA...BUT WILL GET EXTREMELY CLOSE TO THE NORTHWEST BEFORE BECOMING STATIONARY. THE WEST COAST UPPER LOW WILL OPEN AND SPEED EASTWARD OVER THE NEXT 48 HOURS...BRINGING US A CHANCE OF THUNDERSTORMS WEDNESDAY. SOME OF THE STORMS COULD APPROACH SEVERE LIMITS IN THE EAST LATE IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...THE COLD AIRMASS OVER THE CENTRAL PLAINS WILL PUSH SOUTHWARD...BRINGING US CHILLY TEMPS THROUGH THE WEEKEND...WELL BELOW GUIDANCE. 42 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 60 72 40 / 10 10 50 30 WACO, TX 75 62 73 44 / 10 10 50 30 PARIS, TX 72 59 72 41 / 10 10 50 50 DENTON, TX 59 54 71 38 / 10 10 50 30 MCKINNEY, TX 70 59 73 40 / 10 10 50 40 DALLAS, TX 73 60 73 41 / 10 10 50 30 TERRELL, TX 74 61 73 42 / 10 10 50 30 CORSICANA, TX 74 62 74 44 / 10 10 50 30 TEMPLE, TX 75 62 74 45 / 10 10 30 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 1200 PM CST TUE JAN 11 2005 .AVIATION FOR 18Z TAFS... IFR/LIFR MAIN CONCERN THRU THIS TAF PD. LLVLS REMAIN VERY MOIST THROUGH WED AS OVERRUNNING CONTINUES ABOVE FRONTAL INVERSION DUE TO LLVL BAROCLINIC ZONE ACROSS SRN IL/IND AND SERIES OF PASSING MID LVL S/WV TROUGHS. BR/DZ TO PERSIST THRU AFTN HOURS...THOUGH DZ ONLY SPOTTY AS WK S/WV RIDGING OCCURS BEHIND S/WV TROUGH DEPARTING AREA TO THE EAST. NEXT S/WV APPROACHES FROM SRN PLAINS THIS EVE...RESULTING IN NEW ROUND OF OVERRUNNING PCPN DURGN THE NGT. TEMPS ABOVE FRZG ALL TERMINALS AT 18Z...AND EXPECT TEMPS TO REMAIN FAIRLY STEADY THRU TNGT PREVENTING ANY SIG FRZG PCPN THREAT EVEN AT KRFD. RA SHOULD THEN TAPER OFF TO DZ AGAIN FOR A TIME WED MORN BEWEEN WAVES. CIGS/VIS CURRENTLY IN IFR RANGE ALL TERMINALS...THOUGH LIFR CONDITIONS JUST TO THE SOUTH ACROSS CNTRAL IL. THIS LIKELY TO ADVECT NORTH INTO TERMINALS OVRNGT AS LLVL BAROCLINIC ZONE FCST TO EVENTUALLY LIFT NORTHWARD WITH TIME...ESPECIALLY WED MORNING WITH ALL MODELS BRINGING WINDS AROUND SE OVERNIGHT AND S WED MORNING. THUS HAVE GONE WITH LIFR CONDITIONS DOWNT TO 1/2SM AND OVC002 EARLY WED. HAVE TRIED TO INDICATE SLIGHT IMPROVMENT TOWARD END OF TAF PERIOD...AS MAIN LONG WAVE TROUGH TRANSLATES EAST AND PUSHES WARM FRONT FARTHER NORTH. THIS AND HEAVIER RA DVLPG MIDDAY ONWARD SHOULD HELP RAISE CIGS/VIS A BIT. TAF MIGHT BE A LITTLE OPTIMISTIC WITH TIMING...BUT HOPEFULLY INDICATES TREND INTO WED AFTN. RATZER && .DISCUSSION WILL BE UPDATING THE ZONES TO CLEAR UP SNFL AMOUNTS ACROSS THE NRN ZONES. PER UPSTREAM 88DS IN IA, THE POTPOURRI OF WEATHER SHOULD TAPER DOWN AROUND 10 AM LEAVING LIGHT SCATTERED ACTIVITY THROUGH THE REST OF THE DAY. LATEST RUC TEMP VALUES CONTINUE THE TREND FOR A ...SLOW...UPWARD TREND TO TODAY'S SFC TEMPS...HANGING ON TO NEAR 32F TEMPS ACROSS THE NW ZONES. WILL NEED TO KEEP AN EYE ON THINGS FOR TONIGHT AS FZDZ COULD BE AN ISSUE NORTH OF I-88. UPDATED ZFP WILL BE OUT SOON. ...PREV DISC BELOW... WILL BE EXTENDING THE END TIME FOR THE CURRENT ADVISORY TO END AT 18 UTC. ONLY NWP CLOSEST TO CURRENT SFC/88D TRENDS IS THE RUC20 AS THE ETA IS TOO COLD AT THE SFC THRU H925. AN INVERTED SFC TROUGH ACROSS THE CWA, CLEARLY RESOLVED BY THE NRN IL/IN MESONET STATIONS, HAS PLAYED HAVOC WITH THE SFC TEMPS AND AS A RESULT PRECIP TYPES/DURATION. THE TROUGH HAS SLIPPED SOUTH AND EAST OVER THE PAST 8 HRS INHIBITING SFC TEMP WARM UP. NORTH OF THE TROUGH AND APPARENTLY ALONG THE H85 STRENGTHENING BAROLCINIC AND CONFLUENCE ZONE, A PERSISTENT MESOBAND OF SN CONTINUES THIS MORNING FOR LOCATIONS NORTH OF I88. THUS FAR UNDER THAT BAND 5 INCHES OF NEW SNOW HAS BEEN REPORTED NEAR GURNEE, 4 AT LAKE VILLA AND 3.5 INCHES 7-8 MILES WNW OF RFD. IT APPEARS THE THAT BAND WILL HOLD TOGETHER BETWEEN RFD TO UGN FOR ANOTHER FEW HRS. WOULD NOT BE SURPRISED TO SEE LOCALIZED 6/7" AMOUNTS BASED ON THE AFOREMENTION REPORTS. WILL NOT BE ISSUING A WARNING GIVEN THE ISOLATED NATURE RESIDING WITHIN THE CURRENT WINTER WEATHER ADVISORY. THE BULK OF THE STEADIER/HEAVIER PRECIP IS NOW EXPECTED TO TAPER OFF NEAR SUNRISE...WITH SCATTERED PRECIP CONTINUING THRU THE DAY WITH PATCHY/AREAS OF FG/BR. TEMPS SHOULD SLOWLY WARM BUT HAVE HELD MIXED WORDING ACROSS THE FAR NW COUNTIES THROUGH THE DAY AS THAT AREA WILL TAKE THE LONGEST TO WARM ABOUT 32F. FROM THERE...HAVE FOLLOWED THE ETA FROM TONIGHT THRU THR MORNING AS THE LATEST GFS APPEARS TOO FAR NORTH WITH ITS SFC FEATURES VS. THE POSITION OF THE LOW-MIDLVL BAROCLINIC ZONE. TONIGHT NW IN STANDS TO RECEIVE THE LARGEST PRECIP AMOUNTS AS THE NEXT S/WV PASSES ACROSS THE REGION. HAVE ADDED AREAS OF FG FOR TONIGHT THRU WED NIGHT. WED AFTERNOON INTO WED NIGHT WILL SEE THE ARRIVAL OF THE LAST IN THE RECENT SERIES OF S/WV TROUGHS. MODEL QPFS PRODUCE 3/4 TO 1.5 INCHES OF ADDITIONAL RAINFALL ACROSS THE CWA. WILL HOIST AN AREAL FLOOD WATCH FOR THE ENTIRE CWA VALID 00 UTC THR TO 12 UTC THR AS RUNOFF ATOP THE RESIDUAL SNOW PACK, BLOCKED DRAINS/CULVERTS, AND/OR THE CURRENT HIGH SOIL MOISTURE COULD CAUSE LOW SPOTS TO FILL WITH WATER. SHOULD SEE A CHANGE OVER TO SN LATE WED NIGHT BEHIND A STRONG COLD FRONT. AT THIS TIME ACCUMULATIONS APPEAR LIGHT. -SHSN LINGER INTO THRU MORNING WITH TEMPS FALLING THROUGH THE DAY. LEFT THE COLD EXTEND PERIODS IN TACT THIS GO AROUND. && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...DENSE FOG ADVSRY THRU 6 AM WED FOR FORD...GRUNDY...IROQUOIS...KANKAKEE...LA SALLE AND LIVINGSTON COUNTIES. FLOOD WATCH ALL IL COUNTIES THRU 6 AM THURS. .IN...DENSE FOG ADVISORY THRU 6 AM WED BENTON...JASPER...AND NEWTON COUNTIES. FLOOD WATCH ALL IN COUNTIES THRU 6 AM THURS. .LK MI...NONE. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1255 PM EST TUE JAN 11 2005 .AVIATION... LIGHT RAIN ENDING OVER CWA. EXPECT CONDITIONS TO DETERIORATE TO IFR ACROSS NORTHERN INDIANA BY THIS EVENING. THERE IS A CHANCE OF THUNDER LATER TONIGHT AS THE WARM FRONT APPROACHES...MENTIONED IN FWA TAF TOWARD WEDNESDAY MORNING. THERE IS TOO MUCH UNCERTAINTY TO MENTION THIS AT SBN IN THE MORNING. CONDITIONS WILL IMPROVE A LITTLE BY WEDNESDAY AFTERNOON. && .PREV DISCUSSION... SHORT TERM... TODAY AND TONIGHT INITIAL WAVE/I295 CROSS ISALLOBARIC FLOW GENERATING ADVISORY LEVEL PRECIP ACROSS NORTHERN THIRD OF CWA AS FAIRLY FAST MOVING. IN MICHIGAN CURRENTLY BEST LIFT AND DYNAMIC/EVAPORATIVE COOLING WITH 900-700 MB INITIAL DRY LAYER ENOUGH TO KEEP PROFILE COLD ENOUGH FOR SNOW WITH ONE REPORT OF NEAR 2 INCHES ALREADY NEAR STATE LINE. HAVE CHANGED HEADLINE TO WINTER WEATHER ADVISORY FOR MICHIGAN COUNTIES...FURTHER SOUTH WILL CONTINUE WITH FREEZING RAIN ADVISORY WITH A MENTION OF BRIEF PL/SN MIX. BUT PRIMARILY ZR AS PTYPE. IN WAKE OF WAVE LATER THIS AM...IN MICHIGAN SHOULD SEE COLUMN REVERT TO FZRA PROFILE PER RUC/GFS SOUNDINGS WITH LACK OF SIGNIFICANT LIFT/COOLING. KEPT MAX TEMPS CLOSER TO A BIT BELOW COOLER MAV GUIDANCE WITH SNOW/ICE COVER AND LOW LEVEL THERMAL BAROCLINIC ZONE SETTING UP FURTHER SOUTH THAN ETA. PREFERENCE LIES MORE TOWARD CONSISTENT GFS WITH THIS RESPECT. LATER TONIGHT ANOTHER STRONGER SHOT OF I300 LIFT WITH GOOD MOISTURE TAP OF 5-6.5 G/KG ACROSS LOWER OHIO VALLEY AND HAVE BUMPED POPS TO 100 PERCENT CATEGORICAL BUT NO CHANCE TO BEAT MAV WITH 97-100 POPS. FOCUS SHIFTS LATER TONIGHT WITH QPF/WARMING TEMPS TO START OF RUNOFF/FLOOD ISSUES WITH WIDESPREAD SWE OF 1-2 INCHES PLUS ACROSS CWA AND ANTICIPATE WIDESPREAD BASIN AVERAGE RAINFALL TOTALS OF 0.5-1 INCHES BY WEDNESDAY NIGHT. THUS HAVE ISSUES FLOOD WATCH FOR POTENTIALLY SIGNIFICANT FLOODING LATE TONIGHT AND CONTINUE THROUGH WEDNESDAY NIGHT. LONG TERM... WEDNESDAY THROUGH MONDAY MAJOR PATTERN CHANGE WILL TAKE PLACE IN THE EARLY PART OF THE EXTENDED PERIOD WITH A RETURN TO BELOW NORMAL TEMPS BY THURSDAY NIGHT. PATTERN...THE NEGATIVE PNA PATTERN OF THE PAST FEW WEEKS WILL FLIP INTO A MORE TYPICAL MID WINTER POSITIVE PNA PATTERN BY THE END OF THIS WEEK. GFS ENSEMBLE MEAN PNA INDEX FORECAST SHOWING HIGH CONFIDENCE IN THIS PATTERN ADJUSTMENT. A STRONG PACIFIC CUTOFF LOW NOW MOVING ONSHORE INTO CALIFORNIA WILL EJECT THROUGH THE SOUTHWEST US AND INTO THE PLAINS BY MIDWEEK. THIS SYSTEM WILL PHASE WITH A STRONG NORTHERN STREAM SHORTWAVE DROPPING SOUTHEAST THROUGH THE CANADIAN PRAIRIES WITH A RAPIDLY DEEPENING SURFACE LOW CUTTING THROUGH THE LAKES WED NGT AND THURS. THE POLAR VORTEX WILL DROP INTO PLACE BEHIND THIS SYSTEM AND TAKE UP ITS TYPICAL MID WINTER RESIDENCE NEAR HUDSON BAY BY THE END OF THE WEEK. GFS ENSEMBLE MEAN FORECAST OF THE NAO AND AO INDICES INDICATING A GENERAL TREND TOWARDS A MORE NEGATIVE PHASE OF THE NAO BY LATE JANUARY SUGGESTING THAT THE COLDER PATTERN MAY BEGIN TO LOCK INTO THE EASTERN HALF OF THE CONUS. DEEP SOUTH FLOW AHEAD OF THE PACIFIC SYSTEM WILL DEVELOP ON WED. 925MB TEMPS SOAR TO +12C WHICH WOULD SUPPORT UPPER 50S EVEN WITH PURELY MOIST ADIABATIC MIXING. WARM SECTOR WILL BE MOIST AND AMPLE CLOUD COVER SHOULD KEEP TEMPS ON THE MORE CONSERVATIVE SIDE OF GUIDANCE NUMBERS WITH LOW 50S NORTH AND MID 50S SOUTH. INGREDIENTS COMING TOGETHER FOR A HEALTHY PERIOD OF RAIN WED NIGHT. PLUME OF ANOMALOUSLY MOIST AIR ADVECTS INTO THE CWA WITH PWATS OF OVER 1 INCH. LARGE SCALE LIFT WILL INCREASE OVERNIGHT WITH ADVANCING MID LEVEL TROUGH AND ASSOCIATED JET DYNAMICS. THIS WILL COMBINE WITH STRONG LOW LEVEL FRONTOGENETICAL FORCING TO PRODUCE A BAND OF DEEP LIFT ALONG THE SURFACE FRONT. ENOUGH DYNAMICS AND DEEP MOISTURE TO CONTINUE WITH MENTION OF ISOLATED THUNDER WITH TOTAL TOTALS AROUND 50. STRONG FROPA THURSDAY MORNING. GFS/CANADIAN GEM/ETA IN GOOD AGREEMENT WITH TIMING OF SURFACE FRONT WITH THE FRONT BISECTING THE CWA AT 12Z THURS. ECMWF A LITTLE SLOWER AND DISCOUNTED FOR NOW. THIS MAKES THE MAX TEMP FORECAST INTERESTING FOR THURSDAY AS JUST A FEW HOURS IN TIMING WILL MAKE A 20+F DIFFERENCE. WILL START TEMPS OFF IN THE UPPER 40S EAST TO MID/UPPER 30S WEST WITH FALLING TEMPS ALL DAY IN VERY STRONG CAA REGIME. BEST FORCING SHIFTS QUICKLY EAST OF THE CWA DURING THE MORNING. WILL CARRY LIKELY POPS EARLY IN THE EAST THEN TAPER POPS BACK TO CHANCE WITH SKIES BECOMING PARTLY CLOUDY BY AFTERNOON WITH SURFACE RIDGE BUILDING IN BEHIND SURFACE FRONT. THURSDAY NIGHT THROUGH THE WEEKEND A COLD ARCTIC AIRMASS WILL DOMINATE THE CWA. NO WEATHER TO WORRY ABOUT SYNOPTICALLY...SO OUR ATTENTION TURNS TO THE MESOSCALE. GFS SHOWING 850MB TEMPS IN THE -20C TO -24C RANGE POURING ACROSS LAKE MICHIGAN THURS NGT THROUGH SAT NGT. SYNOPTIC PATTERN WOULD SUGGEST WESTERLY FLOW WITH RELATIVELY LOW INVERSION HEIGHTS AND VERY LIMITED AMBIENT MOISTURE. LAKE EFFECT BANDS WILL HAVE TO OVERCOME SHORT FETCH AND SPARSE SYNOPTIC MOISTURE AVAILABILITY. HAVING SAID THAT...WEAK SHORTWAVES AND SURFACE TROUGHS ROTATING THROUGH THE MEAN NW FLOW ALOFT CAN SIGNIFICANTLY IMPROVE THE LAKE EFFECT SETUP AT TIMES IN THIS KIND OF PATTERN. THESE SHORTWAVES CANNOT BE TIMED THIS FAR IN ADVANCE. FOR NOW WILL KEEP CHANCE POPS IN COUNTIES FAVORED BY WESTERLY FLOW THROUGH THE FIRST HALF OF THE WEEKEND. SUB ZERO LOW TEMPS WILL BE POSSIBLE ON NIGHTS WHEN SKIES CLEAR AND WINDS ARE CALM. BEST CHANCE APPEARS TO BE FRIDAY NIGHT INLAND AWAY FROM LAKE EFFECT CLOUDS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. MI...FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. OH...FLOOD WATCH ALL ZONES LATE TONIGHT THROUGH THURSDAY MORNING. && $$ WAMSLEY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1230 PM EST TUE JAN 11 2005 .AVIATION AND UPDATE... PREDOMINATELY IFR CONDITIONS OVER THE NEXT 24 HOURS. DRIER LOW LEVELS OVER TRI-CITIES REGION MAY ALLOW FOR MVFR CONDITIONS THIS AFTERNOON INTO THIS EVENING. WITH A WARM FRONT AND HEAVIER SHOWERS LIFTING INTO THE REGION LATE TONIGHT...COULD SEE A FEW HOURS OF LIFR CONDITIONS BETWEEN 9-14Z. WILL CONTINUE TO MENTION A PERIOD OF FREEZING RAIN FOR KMBS (4-8Z). FLINT HAS A CHANCE OF SEEING A BRIEF PERIOD OF FREEZING RAIN...BUT WILL NOT INCLUDE IN THE TAF. THE DETROIT AREA SHOULD ESCAPE SEEING ANY FREEZING RAIN. WAVE OVER THE OHIO VALLEY NOW PULLING EAST...WITH PRECIPITATION CONTINUING TO DIMINISH OVER SOUTHERN LOWER MICHIGAN. TEMPERATURES HAVE RISEN ABOVE FREEZING ACROSS MOST OF SOUTHEAST MICHIGAN. THIS IS VERY IMPORTANT IN TERMS OF TONIGHT'S EVENT. STRONG WARM FRONT WILL LIFT INTO SOUTHERN LOWER MICHIGAN. VERY IMPRESSIVE SURGE OF WARM AIR...AS 850 MB TEMPS CLIMB ABOVE 5 C BY WEDNESDAY MORNING. WITH SURFACE DEW POINTS ALREADY IN THE LOWER 30S OVER THE SOUTHERN HALF OF THE CWA...NOT ANTICIPATING FREEZING RAIN BEING MUCH OF A PROBLEM...AS THERE SHOULD BE LITTLE IN THE WAY OF LOW LEVEL COLD ADVECTION. ETA MOST TEMPS ARE MUCH TOO COLD. GFS MOS GUIDANCE TEMPS SEEM TO BE THE MOST REPRESENTATIVE AT THE PRESENT TIME...AND THUS WILL GENERALLY FOLLOW FOR TONIGHT. WILL CONSIDER A WINTER WEATHER ADVISORY FOR TRI-CITIES AND THUMB REGION WITH THE AFTERNOON PACKAGE. PROFILES ACTUALLY SUPPORT SNOW IN THE EVENING...CHANGING TO FREEZING RAIN BY SUNRISE WEDNESDAY. WILL NOT BE FORECASTING ANY FREEZING RAIN FOR THE ANN ARBOR/DETROIT AREA AND POINTS SOUTH. ALL EARLIER HEADLINES HAVE BEEN CANCELLED/EXPIRED. && SF && .PREV DISCUSSION...ISSUED 342 AM EST TUESDAY AN EXTREMELY COMPLEX EVENT UNFOLDING WITH A VARIETY OF PRECIP TYPE ISSUES THE NEXT 12-18 HOURS TO BE FOLLOWED BY A STRONG LINE OF CONVECTION AND HEAVY RAINFALL POTENTIAL...WHICH WILL LEAD TO THE ARCTIC BLAST THURSDAY INTO THE UPCOMING WEEKEND. WATER VAPOR AND RADAR IMAGERY IMAGERY SHOW SEVERAL PLAYERS WORKING TOGETHER FOR THIS NARROW, YET INTENSE, REGION OF PRECIPITATION. SHORT WAVE, ALBEIT BECOMING MORE STRUNG OUT, WAS PROGRESSING ACROSS ILLINOIS/INDIANA. TO OUR NORTH A DEPARTING 130KT 300MB JET WAS AIDING IN THE LIFT PROCESS ACROSS NORTHERN INDIANA AND OUR FIRST SHOT OF WARM ADVECTION. LATEST RUC ANALYSIS SHOWS THIS NICELY WITH TIGHTENING THERMAL GRADIENT IN THE 800-700MB LAYER AND 2D-FGEN FORCING WAS VERY IMPRESSIVE ACROSS THE MICHIGAN STATE LINE. HOWEVER, ANOTHER REGION OF THERMALLY INDUCED FGEN WAS WEAKENING TO OUR NORTH AS THERMAL STRUCTURE IS EXPECTED TO WEAKEN TOWARD 12Z. TAKING THE LATEST RUC, REGION OF FGEN AND OMEGA WILL PERSIST ACROSS OUR SOUTHERN 4 COUNTIES THROUGH THIS MORNING AND WEAKEN DURING THE AFTERNOON AS WAVE DEPARTS TO OUR EAST. AS THE SURFACE, 1012MB LOW WAS NEAR KSTL WITH WARM FRONT EXTENDING EAST INTO KENTUCKY WITH 1027MB HIGH JUST EAST OF GEORGIAN BAY. TODAY... WE WILL CONTINUE WITH OUR ADVISORY FOR THOSE SOUTHERN 4 COUNTIES AND EXPAND IT A TIER NORTH THIS MORNING AS THEY WILL REMAIN NEAR THE FGEN FORCING AND FAVORABLE POSITION OF OUR DEPARTING JET THROUGH THE REMAINDER OF THE MORNING HOURS. MODELS ARE FAIRLY SIMILAR ON THIS SITUATION BUT DISAGREE WITH SUBTLE, YET SIGNIFICANT, TEMPERATURE PROFILES. SOME ABOVE 0C TEMPS @ 925MB WERE ATTEMPTING TO MOVE INTO ADG-TTF VICINITY WITH THE LATEST TAMDAR DATA FROM DTW SHOWING SIGNS OF NEAR 0C BETWEEN 800-900MBS. WITH THAT IN MIND...THINK WE WILL SEE A LITTLE MORE OF A MIX TO HOLD DOWN OUR ACCUMULATIONS SOMEWHAT BUT IT WILL BE CLOSE. WITH THIS AMOUNT OF LIFT AND UPSTREAM RADARS VERY BRIGHT THIS MORNING...WE COULD SEE ACCUMULATIONS APPROACH 6" IF WE ARE ABLE TO KEEP THE LAYERS BELOW 0C (WE HAVE 4 G/KG IN THE 850-700MB LAYER WITH IMPRESSIVE ISENTROPIC LIFT IN THIS LAYER). THIS WILL DOMINATE OUR WEATHER TODAY AS WE WILL SEE THIS SYSTEM AND DYNAMICS WEAKEN AND PASS TO OUR EAST DURING THE AFTERNOON. HOWEVER, AS WE LOSE SOME THE MID LEVEL MOISTURE (AOA 700MB), ENOUGH SHEAR IN THE PROFILE SUGGESTS SOME FREEZING DRIZZLE/FLURRIES ACROSS THE NORTH. TEMPERATURES TODAY WOULD EXPECT TO BE COOLER THAN THOSE ADVERTISED IN THE LATEST MOS NUMBERS. BASED ON TRAJECTORIES AND EXTENSIVE CLOUD SHIELD, WOULD THINK TEMPS HOLDING THE LOWER-MIDDLE 30S. TONIGHT... THE POTENTIAL EXISTS FOR ANOTHER HEADLINE ACROSS THE NORTHERN HALF OF OUR CWA BUT THIS WILL BE REFINED WITH THE UPCOMING DAY SHIFT. LATEST GUIDANCE SUGGESTS THE NEXT BIG SURGE OF WARM THETA-E ADVECTION TO OCCUR TOWARD 06Z AS POWERFUL PACIFIC SYSTEM EJECTS INTO THE PLAINS. SHARP 850MB FRONT WILL SWING NORTH OVERNIGHT AND LIKELY PRODUCE SOME PRECIPITATION BEFORE THE MAIN SURFACE WARM FRONT APPROACHES. WITH THAT, WE HAVE AN ISSUE WITH NEAR SURFACE TEMPS. SOUNDINGS AND 3-HOURLY MOS VALUES SUGGEST WE COULD HAVE AN ACCUMULATING ICE EVENT UNFOLDING ACROSS THE NORTHERN HALF. THE QUESTION WILL BE TIMING OF THE WARM AIR AND THE PRECIP AMOUNTS AS USUALLY THE ETA HAS A BETTER HANDLE ON LOWER LEVEL TEMPS THAN THE GFS IN THESE TYPES OF SITUATIONS. HOWEVER, WE COULD HAVE ENOUGH LATENT HEAT RELEASE OF ANY FROZEN PRECIP (WHICH WOULD BE ON THE LIGHT SIDE INITIALLY) TO RAISE TEMPS JUST ABOVE FREEZING TO RESULT IN LITTLE OR ANY PROBLEMS. AS PREVIOUSLY MENTIONED, THIS WILL NEED TO BE MONITORED VERY CLOSELY AND WE WILL MAKE MENTION IN THE HWO. WEDNESDAY... WE FINALLY (WE HOPE) LOSE OUR PRECIP TYPE ISSUES AS SURFACE WARM FRONT RACES NORTH. VERY IMPRESSIVE WARM ADVECTION (850MB JET IN EXCESS OF 50KTS) WITH ELEVATED FACTORS SUGGESTING WE WILL NEED TO ADD IN SOME THUNDER POTENTIAL. THE INITIAL SURGE WILL OCCUR IN THE MORNING BUT WITH STILL DEEP THETA-E AIR OVERHEAD DURING THE AFTERNOON, WE WILL CONTINUE WITH LIKELY POPS THRU THE DAY. WE SHOULD LOSE OUR SNOW COVER FAIRLY QUICKLY AND EXPECT TEMPS TO CLIMB THROUGH THE 40S. WE MIGHT HAVE A FAIRLY EXTENSIVE FOG EVENT EARLY ON BUT AS WE LOSE THE SNOW COVER...VISIBILITIES WILL SLOWLY COME UP IN THE AFTERNOON. WEDNESDAY NIGHT... POWERFUL SHORT WAVE HEADS INTO THE PLAINS WITH NEAR PHASING ACROSS THE WESTERN LAKES WITH POLAR WAVE DIVING SOUTH TOWARD THE DAKOTAS OVERNIGHT. WITH VERY STRONG SOUTHERLY WINDS ALOFT TRANSPORTING PWATS IN EXCESS OF 1" AND ELEVATED STABILITY FACTORS SUGGESTIVE OF A SQUALL LINE MOVING ACROSS LATE... WE WILL NEED TO MONITOR FOR DAMAGING WIND GUSTS AND FLOODING ACROSS THE ENTIRE REGION. TEMPERATURES WILL CONTINUE TO RISE INTO THE 50S FOR MOST LOCATIONS OVERNIGHT. THURSDAY... IF TIMING WORKS OUT... WE WILL TRULY EXPERIENCE THE 4-SEASONS IN A SPAN OF 12 HOURS. LINE OF CONVECTION RACES EAST EARLY IN THE MORNING WITH 50 DEGREE TEMPS AND BY AFTERNOON (AKA 00Z)... 850MB TEMPS WILL BE APPROACHING -15C ACROSS OUR WESTERN COUNTIES WITH SOME SNOW SHOWERS FROM LAKE MICHIGAN AND ANY AVAILABLE MOISTURE LEFT IN THE ATMOSPHERE. WITH SUCH A STRONG FROPA...ANOTHER ROUND OF DAMAGING WIND GUSTS IS POSSIBLE AS MIXING LAYER HEIGHTS QUICKLY CLIMB AND NOT TO MENTION THE STRONG DECENT. REMAINDER OF THE FORECAST LOOKS IN GOOD SHAPE (AND QUITE COLD). ANOTHER HEADLINE MAY BE NEEDED...IN THE FORM A WIND CHILL ADVISORY. WITH TEMPERATURES INTO THE LOWER SINGLE DIGITS AND WINDS STILL AROUND 15 KTS...WIND CHILL READINGS FALL TO DANGEROUSLY LOW -20F. THANKS FOR THE COLLABORATION GRR, IWX AND APX! && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ DWD/BGM HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 339 PM EST TUE JAN 11 2005 .SHORT TERM (TODAY THROUGH WEDNESDAY NIGHT)...WX PATTERN GENERALLY UNCHANGED WITH ANOTHER ROUND OF FOG EXPECTED TONIGHT. THE FLOW OVERNIGHT WILL TURN TO THE SW WHICH WILL ADVECT WARMER/HIGHER DEW POINTS IN THE 60S OVER THE COOL 50-ISH DEGREE COASTAL WATERS. THIS COULD PRODUCE SOME LOCALLY DENSE FOG IN S WATERS AND AREAS NEAR THE BEACHES THIS EVENING. OVERNIGHT THE FOG IS LIKELY TO SPREAD MORE INLAND AND LAST THROUGH SUNRISE. TEMPS ON WED WILL CLIMB A FEW DEGREES WARMER THAN TODAY REACHING THE LOW 70S. FOR TUE NT/WED COULD SEE AN INCREASE IN FOG/STRATUS IN THE OVERNIGHT HOURS...CLEARING TO WARM TEMPS NEAR RECORD IN THE MID 70S. && .LONG TERM (THURSDAY THROUGH MONDAY)...AS THE GENERAL PATTERN BECOMES MORE AMPLIFIED WITH THE RIDGE SLIDING OFFSHORE AND A DEEPENING TROF ACROSS THE CENTRAL US...WARM/HUMID TROPICAL AIR WILL FILTER INTO THE REGION ON STRONG S FLOW. THIS WILL SATURATE THE AIR COLUMN ALLOWING FOR A CHANCE OF SHOWERS DURING THE DAY THU. BY THU NT...THE TRAILING COLD FRONT ASSOCIATED WITH THE SFC LOW IN THE GREAT LAKES WILL BRING ENOUGH DYNAMICS TO GENERATE SOME ISOLD TSRA. HIGH QPF VALUES AND PRECIPITABLE WATER LVLS OVER AN 1.8" COULD LEAD TO TOTAL RAINFALL AMOUNTS OF 1-2" OR HIGHER ACROSS THE CWA. HPC LATEST GUIDANCE SUGGEST SOME AREAS RECEIVING AROUND 3-4". AMOUNTS WILL EVENTUALLY DEPEND ON HOW SOON THE COLD FRONT CAN BRING DRIER AIR INTO THE REGION. THERE HAS BEEN A GENERAL TREND TO SLOW THE FRONT DOWN FRI EVENING....SO WILL NOT TRY AND PINPOINT FROP WITH POPS AS YET OTHER THAN LATE FRI. AFTER FROPA...ECMWF SUGGEST A WAVE DEVELOPING ALONG THE FRONT OFFSHORE WITH A RETURN OF MOISTURE TO THE REGION KEEPING A CHANCE OF SOME LIGHT RAIN PRIMARILY ALONG THE COAST THROUGH SAT. THE ECMWF IS FAVORED BY HPC AND WORKS BEST WITH SURROUNDING OFFICES SO HAVE BASED TIMING AND POPS PRIMARILY ON IT AND A BLEND OF THE GFS. TEMPERATURES WILL HAVE A HARDER TIME COOLING OFF ON THE BACKSIDE OF THE FRONT WITH THE LINGERING LOW OFFSHORE RETURNING LOW LVL MOISTURE...SO HAVE BUMPED TEMPS AND DEW POINTS A FEW DEGREES. EXPECT TEMPS TO REMAIN ABOVE FREEZING DURING ANY PRECIP EVENTS...SO NO FROZEN PRECIP EXPECTED AT THIS TIME. THE SLOW DOWN OF THE FRONT AND DEVELOPING LOW WILL DELAY THE COLDEST TEMPS UNTIL MON NIGHT WITH MOST AREAS DROPPING BELOW FREEZING. && .AVIATION...VFR FOR MOST PART THIS EVENING WITH FEW AREAS OF MVFR VSBY. AREAS OF IFR FOG/STRATUS OVERNIGHT BUT DO NOT ANTICIPATE WDSPRD LIFR CONDITIONS WITH SW WINDS DEVELOPING. && .MARINE...LATEST MODEL DATA FAIRLY CONSISTENT AND HAS GOOD CONTINUITY WITH PREVIOUS FCST. INITIALIZED WITH RUC FOR REST OF THIS AFTN INTO THIS EVE AS THIS THE ONLY MODEL TO PICK UP ON WEAK SFC WAVE ON BNDRY OFF S COAST THAT HAS DELAYED WINDS COMING AROUND TO SE THIS AFTN. LEANED TOWARD GFS FOR REST OF PERIOD. NO FLAGS THRU WED NIGHT...THEN WINDS INCREASING TO SCA THU AHEAD OF COLD FRONT. WINDS NOW LOOKING MORE NE BEHIND FRONT OVER WEEKEND WITH FRONT STALLING OFFSHORE AND WAVES DEVELPING ALONG IT AND MOVING NE. SPEEDS CONTINUING 20-25 KTS SAT-SUN THEN DECREASING MON. WW3 GENERALLY ACCEPTED FOR SEAS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SHORT TERM/LONG TERM...21/JAMISON MARINE/AVIATION...10/MERRELL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 315 PM EST TUE JAN 11 2005 .AVIATION...VFR FOR MOST PART THIS EVENING WITH FEW AREAS OF MVFR VSBY. AREAS OF IFR FOG/STRATUS OVERNIGHT BUT DO NOT ANTICIPATE WDSPRD LIFR CONDITIONS WITH SW WINDS DEVELOPING. && .MARINE...LATEST MODEL DATA FAIRLY CONSISTENT AND HAS GOOD CONTINUITY WITH PREVIOUS FCST. INITIALIZED WITH RUC FOR REST OF THIS AFTN INTO THIS EVE AS THIS THE ONLY MODEL TO PICK UP ON WEAK SFC WAVE ON BNDRY OFF S COAST THAT HAS DELAYED WINDS COMING AROUND TO SE THIS AFTN. LEANED TOWARD GFS FOR REST OF PERIOD. NO FLAGS THRU WED NIGHT...THEN WINDS INCREASING TO SCA THU AHEAD OF COLD FRONT. WINDS NOW LOOKING MORE NE BEHIND FRONT OVER WEEKEND WITH FRONT STALLING OFFSHORE AND WAVES DEVELPING ALONG IT AND MOVING NE. SPEEDS CONTINUING 20-25 KTS SAT-SUN THEN DECREASING MON. WW3 GENERALLY ACCEPTED FOR SEAS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SHORT TERM...SJ MARINE/AVIATION...JBM nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 427 PM EST TUE JAN 11 2005 .SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)... HAVE USED THE RUC40 FOR THE FIRST 6 HRS OF THE FCST...THEN HAVE BASICALLY USED THE ETA THROUGH THURSDAY NIGHT AS IT DOES NOT DIFFER TOO MUCH FROM THE GFS IN TERMS OF SYNOPTIC FEATURES. A WARM FRONT WAS LOCATED ACROSS SOUTHERN ILLINOIS...SOUTHERN INDIANA AND SOUTHERN OHIO THIS AFTERNOON. THIS FRONTAL SYSTEM WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO WEDNESDAY MORNING. THE AIRMASS REMAINS VERY MOIST FOR EARLY JANUARY. THE PRECIPITABLE WATER ON THE 12Z ILN SOUNDING WAS OVER 300 PERCENT OF NORMAL (PWAT WAS ABOUT 1.07 INCHES). SHOWERS AND THUNDERSTORMS THIS EVENING SHOULD BECOME SCATTERED IN NATURE BETWEEN 00Z AND 06Z... THEN THEY SHOULD INCREASE AGAIN BETWEEN 06Z AND 12Z AS LOW LVL JET PROVIDES CONVERGENCE AND AN UPPER LVL S/WV PROVIDES MID LVL LIFT. AS THE WARM FRONT AND MID LVL S/WV PIVOT NORTHEAST OF CWFA BY WEDNESDAY AFTERNOON...REGION BECOMES ENTRENCHED IN THE WARM SECTOR. HENCE...SHOWERS AND THUNDERSTORMS WILL BE REPLACED WITH A 20 OR 30 PERCENT CHC OF SHOWERS. BOTH ETA AND GFS ARE FORECASTING MAINLY 60S ACRS THE ENTIRE CWFA ON THURSDAY. HIGH TEMPS AT DAYTON... CINCINNATI AND COLUMBUS WILL APCH RECORDS FOR THE DATE. FOR WEDNESDAY NIGHT...PRESSURE GRADIENT TIGHTENS AS COLD FRONT APCHES THE REGION FROM THE WEST. BUFKIT MOMENTUM TOOL INDICATES THAT WINDS COULD GUST AROUND 40 KTS. THIS IS SOMEWHAT IN QUESTION AS WIND GUSTS WILL DEPEND ON HOW STRONG THE SHALLOW ISOTHERMAL /WEAK INVERSION WILL BE WITHIN THE BOUNDARY LAYER. AT THIS POINT... IT SEEMS PRUDENT TO PLACE THESE GUSTS IN THE FORECAST. IF THEY COME TO FRUITION...A WIND ADVISORY WILL HAVE TO BE POSTED IN LATER FCSTS. OTHERWISE...STRONG LOW LVL CONVERGENCE ALONG AND JUST BEHIND COLD FRONT WILL PROVIDE FOR ABOUT A 4 TO 5 HOUR PERIOD OF WIDESPREAD SHOWERS. SHOWERS WILL MOVE IN LATE IN THE WEST WEDNESDAY NIGHT...THEN ACRS THE REMAINDER OF THE CWFA ON THURSDAY. THERE COULD BE AN EMBEDDED THUNDERSTORM WITH THE SHOWERS. ONCE COLD FRONT PASSES BY...PCPN SHOULD COME TO AN END FAIRLY QUICKLY. MUCH COLDER AIR WILL ARRIVE THURSDAY NIGHT WITH READINGS DROPPING INTO THE TEENS AND 20S BY FRIDAY MORNING. SPECIALLY FOR TEMPS...HAVE USED A BLEND OF THE ETA MET/GFS MAV. && .LONG TERM (FRIDAY THROUGH TUESDAY)... ALL EXTENDED MODELS OVER LAST FEW RUNS HAVE BEEN TRENDING TOWARDS SHALLOWING THE PUSH OF ARCTIC AIR SOUTH INTO CNTRL/EASTERN CONUS OVER THE WEEKEND. 00Z GFS AND ECMWF BOTH INDCG MORE OF A ZONAL UPR FLO BY LATE WEEKEND...WITH SFC HI PRES ACRS EASTERN CONUS. 12Z GFS IS NOW EVEN GOING SO FAR AS TO TRY TO REESTABLISH BROAD SW FLO ACRS EASTERN CONUS BY MON NEXT WEEK. THIS IS THE FIRST TIME THIS SOLN HAS BEEN SUGGESTED...AND WILL CONTINUE TO GO WITH THE MORE CONSISTENT COLDER DRIER SOLN SUGGESTED BY THE MODELS FOR THE LAST SVRL DAYS. WILL WARM TEMPS A FEW DEGREES OVER THE WEEKEND BASED ON HIGHER BNDRY LYR THICKNESSES AND SLIGHTLY WARMER 850 TEMPS. IT WILL STILL BE COLD...WITH DAYTIME HIGHS IN THE 20S AND LOWS FROM 5 TO 10 OVER THE WEEKEND. SVRL WEAK DISTURBANCES WILL DROP ACRS GRT LKS ERLY NEXT WEEK BUT WILL LITTLE MOISTURE...EXPECTING JUST AN INCREASE IN CLOUDS SUN THRU TUES. RYAN && .AVIATION(18Z-18Z)... SHOWERS AND ISOLATED THUNDER WILL CONTINUE THROUGH THE AFTERNOON AS A WEAK WAVE MOVES ALONG THE WARM FRONT BISECTING THE AREA. AFTER THE WAVE GOES BY EXPECT THE FRONT TO LIFT THROUGH THE DAYTON AND COLUMBUS AREAS. SHOULD SEE SOME IMPROVEMENT IN THE CEILINGS THIS EVENING IN THE WARM SECTOR WITH LITTLE PRECIPITATION. HOWEVER ADDITIONAL SHOWERS ARE EXPECTED TO DEVELOP AND MOVE NORTH OVER THE TAF SITES AFTER 06Z. THIS PRECIPITATION WILL DIMINISH AFTER DAYBREAK. MAY IMPROVE TO VFR LATE IN THE FORECAST PERIOD AND WINDS WILL BECOME GUSTY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH FOR ZONES OHZ026-035-034-042>046-051>056- 060>065-070>074-077>082-088 UNTIL NOON EST WEDNESDAY. IN...FLOOD WATCH FOR ZONES INZ050-058-059-066-073>075-091 UNTIL NOON EST WEDNESDAY. KY...FLOOD WATCH FOR ZONES KYZ089>100 UNTIL NOON WEDNESDAY. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 353 PM EST TUE JAN 11 2005 .SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)... SERIES OF LOW PRESSURE SYSTEMS WILL MOVE THROUGH THE UPPER OHIO VALLEY INTO THURSDAY NIGHT. THE STRONG LIFT ASSOCIATED WITH THE FIRST SYSTEM'S WARM FRONTAL FRONTOGENESIS AND MOISTURE FLUX CONVERGENCE WILL SPREAD AN ADDITIONAL 0.5-1.0 INCHES OF RAIN TONIGHT INTO WEDNESDAY MORNING. THE RUC MODEL SHOWS THERE IS SUFFICIENT INSTABILITY TO CAUSE THUNDERSTORMS OVER THE UPPER OHIO VALLEY...WHICH CAN RESULT IN INCREASED RAINFALL RATES. WITH 6-12H COUNTY FLASH FLOOD GUIDANCE VALUES ON THE ORDER OF 1.5 INCHES...HAVE ISSUED A FLOOD WATCH FOR MOST OF THE UPPER OHIO VALLEY COUNTY WARNING AREA UNTIL 10 AM WEDNESDAY...BY WHICH TIME THE BULK OF THE RAIN WILL HAVE PUSHED NORTHWARD. FOR THE STRONG COLD FRONTAL PASSAGE ON THURSDAY...WENT WITH THE ETA AND GFS MODELS RUNS THAT CONTINUE TO SHOW THE STRONG COLD FRONT WITH THE SECOND SYSTEM MOVING THROUGH THE UPPER OHIO VALLEY LATE THURSDAY...ALTHOUGH THE ECMWF AND CANADIAN MODEL ARE STILL ABOUT 6H SLOWER. && .LONG TERM (FRIDAY THROUGH TUESDAY)... THE GFS AND ECMWF MODEL RUNS SHOW SHARPLY COLDER TEMPERATURES FOR THIS WEEKEND...BUT PRECIPITATION LIMITED TO SCATTERED LIGHT SNOW SHOWERS...AS THE UPPER JET SWITCHES INTO A NORTHWEST FLOW REGIME. && .AVIATION... LIFR CONDS CONT ACRS MUCH OF FCST AREA THIS AFTN WITH WRMFNT RMNG STRETCHED THRU SRN OH AND NRN WV. AREA OF RAIN CONTS TO SLIDE EWD TO THE N OF FNTL BNDRY. TEMPS STILL NEAR FRZG AT DUJ...AND ABV 0C ELSW. EXPECT WRMFNT TO MAKE ONLY VERY SLO NWD PROGRESS TNGT...SO LIFR/IFR CONDS SHUD PERSIST IN RAIN AND FOG OVRNGT. AS WRMFNT PUSHES NWD THRU RGN WED MRNG...CONDS SHUD IMPROVE TO MVFR CIGS AND VIS. && .PREVIOUS DISCUSSION... (ISSUED 203 PM EST TUE JAN 11 2005) SHORT TERM (REST OF TODAY THROUGH TONIGHT)... WHERE TEMPERATURES HAVE WARMED ABOVE 32 DEGF HAVE DROPPED APPROPRIATE WINTER TYPE ADVISORIES AND WARNINGS. REST WILL END AT 330PM. PREVIOUS DISCUSSION... (ISSUED 839 AM EST TUE JAN 11 2005) SHORT TERM (REST OF TODAY THROUGH TONIGHT)... GETTING REPORTS OF ICE ACCUMULATIONS NORTH OF PITTSBURGH...SO HAVE ISSUED APPROPRIATE WINTER STORM TYPE WARNINGS. EXPECT PRECIPITATION AMOUNTS SIMILAR TO HPC LATEST FORECASTS...0.5 TO 0.8 INCHES THROUGH 00Z. THIS CAN RESULT IN A 2-4 INCHES OF SNOW NORTH WITH ICE ACCUMULATIONS OVER 0.25 INCHES. WILL MONITOR RAIN IN SOUTH FOR POSSIBLE FLOOD CONCERNS...BUT 3HR COUNTY FLASH FLOOD GUIDANCE VALUES ARE GENERALLY 1.5 INCHES. PREVIOUS DISCUSSION... (ISSUED 319 AM EST TUE JAN 11 2005) SHORT TERM (TODAY THROUGH THURSDAY)... WL BE A RACE TDA OF PCPN AND WARM AIR VS COLD AIR OVR THE NRN HALF OF THE CWA. WL MAKE MENTION OF SN...THEN FZRA...TURNING TO ALL RA LTR THIS AFTN FOR THE NRN MOST ZONES. WL ALSO HAVE TO MENTION FZRA AS FAR SOUTH AS PIT GIVEN CURRENT TEMPS ALTHOUGH NOTHING SIGNFICANT WITH RISES IN ACCOMPANIMENT WITH PCPN. WL GO WITH AN ADVISORY OVR THE NRN ZONES TO COVER NUISANCE OF -FZRA AND LGT SN COMBO. OTHERWISE...BEST RA CHCS RMNS WITH NWD SURGING WARMFNT THRU WED...PLACEMENT OF WHICH RMNS QNABLE. CDFNT CONSISTENTLY EXPECTED LATE ON THU. BOTTOM LINE IS NO MAJOR CHANGES TO POP PROG IN THE SHORT TERM. LONG TERM (FRIDAY THROUGH MONDAY)... MUCH COLDER TEMPS AND LAKE ENHANCED SHSN WL FOLLOW THE FRONT IN THE LONG TERM WITH LOW OVER THE HUDSON BAY PROPPING THE DOOR OPEN FOR THE WEEKEND. AVIATION... GENERALLY MVFR TO IFR CIGS/VSBYS ACROSS THE CWA TODAY AND TONIGHT AS PCPN MOVES EASTWARD ALONG WARM FRONTAL BOUNDARY. OVER THE SOUTHERN TWO THIRDS OF OUR CWA EXPECT RAIN, BUT OVER THE NORTHERN SECTIONS THIS MORNING INTO THE AFTERNOON HOURS THERE WILL BE MIX OF SNOW, SLEET AND FREEZING RAIN. ALL AREAS WILL GO OVER TO RAIN THIS EVENING AS SURFACE LOW MOVES UP THE OHIO RIVER VALLEY DRAWING WARMER, ABOVE FREEZING AIR, NORTH INTO OUR FA. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...FLOOD WATCH FOR OHZ039-OHZ040-OHZ041-OHZ048-OHZ049-OHZ050- OHZ057-OHZ058-OHZ059-OHZ068-OHZ069 FROM 4 PM TUESDAY UNTIL 10 AM WEDNESDAY. PA...FLOOD WATCH FOR PAZ007-PAZ008-PAZ009-PAZ013-PAZ014-PAZ015- PAZ016-PAZ020-PAZ021-PAZ022-PAZ023-PAZ029-PAZ030-PAZ031- PAZ032 FROM 4 PM TUESDAY UNTIL 10 AM WEDNESDAY. ...WINTER STORM WARNING FOR PAZ007-PAZ008-PAZ009-PAZ015-PAZ016 FROM 3 PM TUESDAY UNTIL 4 PM TUESDAY. ...FREEZING RAIN ADVISORY FOR PAZ013-PAZ014-PAZ022-PAZ023 FROM 3 PM TUESDAY UNTIL 4 PM TUESDAY. WV...FLOOD WATCH FOR WVZ001-WVZ002-WVZ003-WVZ004-WVZ012-WVZ021- WVZ022 FROM 4 PM TUESDAY UNTIL 10 AM WEDNESDAY. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 1039 AM CST TUE JAN 11 2005 .DISCUSSION... STATIONARY FRONT STILL LOCATED JUST TO THE NORTH OF THE MIDSOUTH WITH THE ENTIRE AREA UNDER THE WARM SECTOR. DEWPOINTS IN THE LOWER 60S AREAWIDE. SCATTERED SHOWERS AND THUNDERSTORMS HAVE OCCURRED THIS MORNING DUE TO A SHORTWAVE MOVING THROUGH THE WSW FLOW. THIS SHORTWAVE IS NOW EXITING THE REGION AND THE PRECIP IS TAPERING OFF AND LEAVING THE CWA. RUC/GFS/META ALL SHOW ANOTHER SMALL SHORTWAVE MOVING THROUGH THIS AFTERNOON. GIVEN THE ATMOSPHERE IS MOIST AND MARGINALLY UNSTABLE (CAPES 400-600 J/KG) WILL LEAVE 30 POPS IN FOR THE AFTERNOON. TEMPS FORECAST APPEARS TO BE ON TRACK. SHOULD SEE A FEW BREAKS IN THE CLOUDS...ESPECIALLY OVER EAST ARKANSAS. THIS WILL HELP TEMPS TO REACH THEIR FORECASTED VALUES. IF MORE SUN WERE TO BREAK THROUGH THEN FORECAST LOWS MAY BE TOO LOW. WILL CONTINUE TO MONITOR. OTHER PARAMETERS ON TRACK. ADJUSTED SHORT TERM SKY GRIDS TO MATCH TRENDS. .MAIN POINTS OF PREV DISCUSSION ISSUED 350 AM... TONIGHT...ANOTHER SHORTWAVE EMBEDDED IN THE SOUTHWEST FLOW ALOFT WILL AFFECT THE MID SOUTH EARLY WEDNESDAY MORNING. EVEN WITH CAPES OF 500-600 J/KG...LI/S AROUND -2...AND MODERATE 700-500MB MID LEVEL LAPSE RATES AROUND 6.5 C/KM...I THINK MOISTURE MAY BE THE LIMITING FACTOR IN ANY DECENT CONVECTIVE DEVELOPMENT OVERNIGHT...ESPECIALLY ACROSS NORTHERN MISSISSIPPI AND WILL CARRY ONLY SLIGHT CHANCE POPS ACROSS THE FORECAST AREA WITH BEST CHANCES TOWARDS THE MO/KY BORDER. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO THE 50S. WEDNESDAY AND WEDNESDAY NIGHT...LONG AWAITED STRONG COLD FRONT WILL BEGIN TO APPROACH THE MID SOUTH. 850 MB LOW LEVEL JET WILL INCREASE TO AROUND AN IMPRESSIVE 70 KTS AROUND 03Z THURSDAY AND STRONG MID/UPPER LEVEL FORCING /700-500 MB Q-VECTOR CONVERGENCE/. FURTHER ANALYSIS OF MANY MODIFIED SURFACE AND ELEVATED PARCELS ON MODEL SOUNDINGS SUGGEST SUPERCELL THREAT MAY BE LIMITED TO AREAS PRIMARILY ACROSS NORTHERN MISSISSIPPI AS MID LEVEL CAPPING INVERSION LIMITS INSTABILITY WITH LESS THAN 1000 J/KG TO POINTS NORTH. HOWEVER 0-1KM STORM RELATIVE HELICITY VALUES WILL BE MORE THAN ADEQUATE FOR POSSIBLE SUPERCELLS /350-400 M2/S2/ ALONG WITH A RATHER DECENT SHEAR PROFILE ACROSS MISSISSIPPI. I WOULD ANTICIPATE A FEW SUPERCELLS TO DEVELOP ACROSS MISSISSIPPI WITH A DYNAMIC BOW ECHO EVENTUALLY OVERTAKING ALL CONVECTION AHEAD OF THIS LINE ACROSS THE FORECAST AREA AS WINDS WILL BECOME MORE UNIDIRECTIONAL AND 700 MB DEWPOINT DEPRESSIONS WELL OVER 7C. I WILL BE MENTIONING SEVERE THREAT POTENTIAL BOTH IN THE ZFP FORECAST ALONG AND THE HAZARDOUS WEATHER OUTLOOK. NO CHANGES MADE BEYOND THURSDAY. && .MEG...WATCHES/WARNINGS/ADVISORIES... AR...NONE. MS...NONE. MO...NONE. TN...NONE. && $$ JFB/CJC tn AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE FORT WORTH TX 1140 AM CST TUE JAN 11 2005 .AVIATION... MVFR CIGS SHOULD LIFT/SCATTER OUT IN THE NEXT HOUR OR SO WITH VFR PREVAILING THROUGH THE EVENING. ANOTHER ROUND OF MVFR STRATUS EXPECTED IN AFTER MIDNIGHT AND PERSISTING THROUGH THE TAF CYCLE. SOUTHERLY WINDS WILL STAY UP THROUGH TONIGHT AND BECOME GUSTY AFTER SUNRISE. NO PRECIP EXPECTED THROUGH 18Z. TR/92 && .1050 AM UPDATE... WE WILL UPDATE TO LOWER TEMPERATURES IN THE NORTHWEST ZONES...FOR THE COLD FRONT THAT HAS MOVED INTO THE AREA. AFTERNOON PRESSURE FALLS SHOULD SLOW THE FRONT. IT WILL MOVE NORTHWARD TONIGHT...AS A VIGOROUS MID-LEVEL SHORT WAVE TROUGH APPROACHES. WEDNESDAY COULD BRING SEVERE WEATHER...PARTICULARLY IN THE EASTERN ZONES...AS THE DISTURBANCE MOVES ACROSS OKLAHOMA...AND A LINE OF THUNDERSTORMS FORMS...AND AFFECTS MAINLY EASTERN PORTIONS OF NORTH TEXAS. THE VERTICAL WIND SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE STORMS. HOWEVER...THE STORMS COULD LINE OUT EARLY. THUS...ANY TORNADO/HIGH WIND THREAT MAY COME IN WHATEVER BRIEF PERIOD OF TIME THE STORMS ARE IN A DISCRETE (MORE ISOLATED) MODE. THE TEMPERATURES IN FRIDAY THROUGH WEEKEND PERIOD APPEAR TO BE TOO COLD AT THIS TIME. THURSDAY'S COLD FRONT SHOULD PULL MORE MOUNTAIN AIR INTO TEXAS 9RATHER THAN ARCTIC AIR)...WHICH WILL WARM SOMEWHAT WITH THE DOWNSLOPE FLOW. WE WILL LOOK AT THIS PROBLEM OVER THE NEXT FEW HOURS...AND LIKELY RAISE TEMPERATURES IN THE AFTERNOON PACKAGE FOR DAYS 3-5. #26 && .UPDATE... HAVE ADJUSTED A FEW PARAMETERS TODAY TO REFLECT CURRENT TRENDS AND EXPECTED FRONTAL POSITION. 42 && .AVIATION... 535 AM CST 40-45KTS AT 2000FT REQUIRING LLWS MENTION EARLY THIS MORNING. FRONT IN SW OKLAHOMA HAS NOW PUSHED THROUGH VERNON. FORWARD PROGRESS SHOULD BE STUNTED WITH SW FLOW ALOFT AND THINNING POLAR AIR MASS. PROXIMITY OF FRONT WILL SERVE TO PULL WINDS WEST OF SOUTH. ST/SC ALREADY SEEN EVACUATING ON 11-3.9 IMAGERY AND FURTHER ERODING LIKELY AFTER BRIEF RADIATIONAL STRATUS NEAR DAYBREAK. EXPECT FEW/SCT MORE THAN BKN/OVC. ST/SC TO RETURN OVERNIGHT BUT IFR UNLIKELY WITH STRONG LLJ AND BL WINDS KEEPING THINGS MIXED. FRONT SHOULD RETREAT AND SOUTH WINDS WILL REMAIN THROUGH TAF PERIOD. 25 && .DISCUSSION... 333 AM CST COLD FRONT IN SOUTHWESTERN OKLAHOMA WILL EASE ACROSS THE RED RIVER THIS MORNING INTO OUR NORTHWESTERN ZONES...BEFORE PULLING BACK TONIGHT. DESPITE THE LACK OF UPPER SUPPORT FEEL THE RUC HAS A GOOD HANDLE ON THIS SHALLOW AIRMASS AND HAVE ADJUSTED OUR FORECAST ACCORDINGLY. THIS HAS MADE THE FORECAST RATHER TRICKY IN THAT REGION WITH A STRONG TEMPERATURE GRADIENT DURING THE DAY TODAY. DO NOT THINK IT WILL MAKE IT INTO THE DALLAS...FORT WORTH AREA...BUT WILL GET EXTREMELY CLOSE TO THE NORTHWEST BEFORE BECOMING STATIONARY. THE WEST COAST UPPER LOW WILL OPEN AND SPEED EASTWARD OVER THE NEXT 48 HOURS...BRINGING US A CHANCE OF THUNDERSTORMS WEDNESDAY. SOME OF THE STORMS COULD APPROACH SEVERE LIMITS IN THE EAST LATE IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...THE COLD AIRMASS OVER THE CENTRAL PLAINS WILL PUSH SOUTHWARD...BRINGING US CHILLY TEMPS THROUGH THE WEEKEND...WELL BELOW GUIDANCE. 42 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 60 72 40 / 10 10 50 30 WACO, TX 75 62 73 44 / 10 10 50 30 PARIS, TX 72 59 72 41 / 10 10 50 50 DENTON, TX 59 54 71 38 / 10 10 50 30 MCKINNEY, TX 70 59 73 40 / 10 10 50 40 DALLAS, TX 73 60 73 41 / 10 10 50 30 TERRELL, TX 74 61 73 42 / 10 10 50 30 CORSICANA, TX 74 62 74 44 / 10 10 50 30 TEMPLE, TX 75 62 74 45 / 10 10 30 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 26 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1050 AM CST TUE JAN 11 2005 .1050 AM UPDATE... WE WILL UPDATE TO LOWER TEMPERATURES IN THE NORTHWEST ZONES...FOR THE COLD FRONT THAT HAS MOVED INTO THE AREA. AFTERNOON PRESSURE FALLS SHOULD SLOW THE FRONT. IT WILL MOVE NORTHWARD TONIGHT...AS A VIGOROUS MID-LEVEL SHORT WAVE TROUGH APPROACHES. WEDNESDAY COULD BRING SEVERE WEATHER...PARTICULARLY IN THE EASTERN ZONES...AS THE DISTURBANCE MOVES ACROSS OKLAHOMA...AND A LINE OF THUNDERSTORMS FORMS...AND AFFECTS MAINLY EASTERN PORTIONS OF NORTH TEXAS. THE VERTICAL WIND SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE STORMS. HOWEVER...THE STORMS COULD LINE OUT EARLY. THUS...ANY TORNADO/HIGH WIND THREAT MAY COME IN WHATEVER BRIEF PERIOD OF TIME THE STORMS ARE IN A DISCRETE (MORE ISOLATED) MODE. THE TEMPERATURES IN FRIDAY THROUGH WEEKEND PERIOD APPEAR TO BE TOO COLD AT THIS TIME. THURSDAY'S COLD FRONT SHOULD PULL MORE MOUNTAIN AIR INTO TEXAS 9RATHER THAN ARCTIC AIR)...WHICH WILL WARM SOMEWHAT WITH THE DOWNSLOPE FLOW. WE WILL LOOK AT THIS PROBLEM OVER THE NEXT FEW HOURS...AND LIKELY RAISE TEMPERATURES IN THE AFTERNOON PACKAGE FOR DAYS 3-5. #26 && .UPDATE... HAVE ADJUSTED A FEW PARAMETERS TODAY TO REFLECT CURRENT TRENDS AND EXPECTED FRONTAL POSITION. 42 && .AVIATION... 535 AM CST 40-45KTS AT 2000FT REQUIRING LLWS MENTION EARLY THIS MORNING. FRONT IN SW OKLAHOMA HAS NOW PUSHED THROUGH VERNON. FORWARD PROGRESS SHOULD BE STUNTED WITH SW FLOW ALOFT AND THINNING POLAR AIR MASS. PROXIMITY OF FRONT WILL SERVE TO PULL WINDS WEST OF SOUTH. ST/SC ALREADY SEEN EVACUATING ON 11-3.9 IMAGERY AND FURTHER ERODING LIKELY AFTER BRIEF RADIATIONAL STRATUS NEAR DAYBREAK. EXPECT FEW/SCT MORE THAN BKN/OVC. ST/SC TO RETURN OVERNIGHT BUT IFR UNLIKELY WITH STRONG LLJ AND BL WINDS KEEPING THINGS MIXED. FRONT SHOULD RETREAT AND SOUTH WINDS WILL REMAIN THROUGH TAF PERIOD. 25 && .DISCUSSION... 333 AM CST COLD FRONT IN SOUTHWESTERN OKLAHOMA WILL EASE ACROSS THE RED RIVER THIS MORNING INTO OUR NORTHWESTERN ZONES...BEFORE PULLING BACK TONIGHT. DESPITE THE LACK OF UPPER SUPPORT FEEL THE RUC HAS A GOOD HANDLE ON THIS SHALLOW AIRMASS AND HAVE ADJUSTED OUR FORECAST ACCORDINGLY. THIS HAS MADE THE FORECAST RATHER TRICKY IN THAT REGION WITH A STRONG TEMPERATURE GRADIENT DURING THE DAY TODAY. DO NOT THINK IT WILL MAKE IT INTO THE DALLAS...FORT WORTH AREA...BUT WILL GET EXTREMELY CLOSE TO THE NORTHWEST BEFORE BECOMING STATIONARY. THE WEST COAST UPPER LOW WILL OPEN AND SPEED EASTWARD OVER THE NEXT 48 HOURS...BRINGING US A CHANCE OF THUNDERSTORMS WEDNESDAY. SOME OF THE STORMS COULD APPROACH SEVERE LIMITS IN THE EAST LATE IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...THE COLD AIRMASS OVER THE CENTRAL PLAINS WILL PUSH SOUTHWARD...BRINGING US CHILLY TEMPS THROUGH THE WEEKEND...WELL BELOW GUIDANCE. 42 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 60 72 40 / 10 10 50 30 WACO, TX 75 62 73 44 / 10 10 50 30 PARIS, TX 72 59 72 41 / 10 10 50 50 DENTON, TX 59 54 71 38 / 10 10 50 30 MCKINNEY, TX 70 59 73 40 / 10 10 50 40 DALLAS, TX 73 60 73 41 / 10 10 50 30 TERRELL, TX 74 61 73 42 / 10 10 50 30 CORSICANA, TX 74 62 74 44 / 10 10 50 30 TEMPLE, TX 75 62 74 45 / 10 10 30 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 26 tx