AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 346 PM MST SUN DEC 14 2008 .SHORT TERM... (TONIGHT AND MONDAY) CURRENTLY...SNOW HAD COME TO AN END ACROSS MUCH OF THE CWA SUNDAY AFTN AS OF 3 PM...WITH SOME BREAKS IN THE CLOUD COVER BEING REALIZED. IN FACT...THE SE CORNER OF THE STATE AS WELL AS THE SLV WAS BORDERING ON MOSTLY SUNNY. THE CORE OF THE UPPER JET LAY ACROSS NORTHERN NM AS PER THE RUC ANALYSIS. THE COLD FRONT THAT CAME THROUGH EARLY THIS MORNING USHERED IN SOME VERY COLD AIR...AND TEMPS THROUGHOUT THE DAY HAVE VERY GRADUALLY DROPPED. HOWEVER...THE DEMARCATION LINE LURKED...WITH THE TEMP LANDSCAPE RANGING FROM 11 F IN COS...12 F IN PUB...17 F IN TAD...AND 35 F IN RATON. TONIGHT...AS NAM AND GFS MODELS HAD INDICATED...TONIGHT WILL IN ESSENCE BE A RELOADING PERIOD FOR THE UPPER PATTERN. THE LARGE UPPER LOW REMAINS JUST OFF THE OR AND CA COAST...WITH DEEP W-SW FLOW ALOFT ACROSS THE WESTERN THIRD OF THE COUNTRY. THE FLOW ALOFT ACROSS THE STATE BECOMES NEARLY ZONAL...AND THE ATMOS FOR THE MOST PART DRIES OUT FOR THE NEXT 12 HRS OR SO. STILL...ISOLATED PCPN ALONG THE CONTDVD CAN NOT BE RULED OUT SO LEFT SOME POPS THERE. ELSEWHERE...CUT POPS DRASTICALLY WHILE REALLY STRUGGLING WITH CLOUD COVER. PATCHES OF CLEARING RIGHT NOW SEEMS TO INDICATE CONTINUED CLEARING TONIGHT...WHICH COULD PRODUCE A BITTERLY COLD NIGHT. COOLED MIN TEMPS A FEW DEGREES TONIGHT...THOUGH PREVIOUS THINKING WAS ON THE RIGHT TRACK AND VERY CLOSE. ALSO INCLUDED SOME AREAS OF FOG OVERNIGHT...ESPECIALLY IN THE SLV...EL PASO COUNTY AND ALONG THE LOWER ARKANSAS. FINALLY...THERE ARE A COUPLE OF PINPOINT SPOTS OVER THE HIGHER TERRAIN WHERE WIND CHILL CRITERIA IS MET. HOWEVER...THIS OCCURS FOR 2 OT 3 HRS AT MOST AND IS SO ISOLATED DID NOT FEEL A HIGHLIGHT WAS NECESSARY TONIGHT. TOMORROW...THE ACTIVE WEATHER PATTERN ALOFT CONTINUES...WITH THE UPPER LOW DROPPING DOWN ALONG THE NORTHERN CA COAST AND THE FLOW ALOFT ACROSS THE REGION SHIFTING TO A MORE SW DIRECTION. THIS WILL ONCE AGAIN DRAW A HEALTHY MOISTURE FEED UP ACROSS THE 4 CORNERS AND INTO WESTERN CO. THE TIMING OF THE PCPN SWITCH TURNING BACK ON IS ALWAYS A QUESTION...BUT BOTH NAM AND GFS MODELS SEEM TO SUGGEST RIGHT AROUND MIDDAY IS WHEN THINGS START CRANKING UP AGAIN...WHICH THEN CONTINUES TO PERHAPS THE MIDDLE OF THE WEEK. FOCUS AREA WILL BE ALONG THE CONTDVD ONCE AGAIN...AND WINTER WEATHER HIGHLIGHTS HAVE BEEN HOISTED FOR THAT AREA BEGINNING AT NOON. SNOW SHOULD SPREAD EAST ACROSS THE SLV AND E MTS TO THE I25 CORRIDOR THRU THE AFTN AND EVE AS WELL...BUT SNOW AMOUNTS ARE NOT EXPECTED TO REACH ADV CRITERIA AT THIS TIME. THE UPPER JET SLIDES NORTH AS WELL...UP ACROSS THE CWA...SO GUSTY WINDS AND AREAS OF BLOWING SNOW FOR THE HIGHER TERRAIN IS EXPECTED. AS FOR MAX TEMPS...WENT WITH THE AVG OF NUMERICAL GUIDANCE BUT OF COURSE WILL DEPEND ON CLOUD COVER AND HOW MUCH MIXING CAN OCCUR BEFORE PCPN RESUMES. MOORE .LONG TERM... (MONDAY NIGHT THROUGH NEXT SUNDAY) NEXT PIECE OF UPPER ENERGY HEADS ONSHORE OVER THE WEST COAST MONDAY NIGHT...WITH MOIST SOUTHWEST FLOW REDEVELOPING OVER SOUTHERN COLORADO. STRONG UPPER JET AND 50-60 KNOT SOUTHWEST FLOW AT 700 MB WILL COMBINE TO PRODUCE PROLONGED HEAVY SNOWFALL OVER THE SOUTHWEST MOUNTAINS...WITH AMOUNTS PUSHING 3 FEET AROUND WOLF CREEK PASS BY LATE TUESDAY AFTERNOON. UPGRADED CURRENT WATCH TO A MIX OF WARNING/ADVISORIES FOR THE CENTRAL AND SOUTHWEST MOUNTAINS...OTHERWISE PREVIOUS SET OF FORECAST GRIDS LOOKED OK AND MADE ONLY MINOR CHANGES. SOME CONCERN ABOUT ADVISORY LEVEL SNOWFALL OVER THE EASTERN MOUNTAINS FROM LATE MONDAY NIGHT INTO TUESDAY AS NOSE OF THE UPPER JET MOVES EAST ALONG THE NM BORDER AND FAIRLY STRONG WARM ADVECTION DEVELOPS. VARIOUS MODELS SUGGEST SNOW AMOUNTS OVER THE SANGRES JUST UNDER ADVISORY CRITERIA...SO WILL HOLD OFF FOR NOW. WARM ADVECTION SHOULD PRODUCE SOME LIGHT PRECIP OVER THE PLAINS FROM LATE MONDAY NIGHT INTO TUESDAY...BUT WITH DOWNSLOPE DRYING REDUCING SATURATION AT 700 MB AND ABOVE...MAY NOT SEE MUCH MORE THAN FLURRIES...ESPECIALLY EAST OF I-25. CURRENT POPS MIGHT BE A LITTLE HIGH OVER THE I-25 CORRIDOR ON TUES...BUT STILL ENOUGH UNCERTAINTY TO KEEP FROM CHANGING THINGS MUCH AT THIS POINT. SUSPECT MODELS ARE ERODING COLD AIR TOO QUICK OVER THE EAST ON TUESDAY...SO WILL RUN WITH MAX TEMPS WELL BELOW GUIDANCE NUMBERS. HIGHLIGHTS END TUESDAY EVENING...BUT WITH WESTERN TROUGH SLOW TO MOVE EAST AND STRONG SOUTHWEST FLOW CONTINUING...SNOW MAY NOT COMPLETELY SHUT OFF...ESPECIALLY OVER THE SAN JUANS. COLD AIR SLOSHES BACK SOUTH OVER THE PLAINS AS LOW PRESSURE DEEPENS OVER NORTHEAST NEW MEXICO...SO LITTLE/NO WARMING OVER MUCH OF THE EAST AGAIN WED AFTERNOON...DESPITE OPTIMISTIC GUIDANCE NUMBERS. MAJOR PIECE OF THE WESTERN TROUGH FINALLY CROSSES THE STATE WED NIGHT AND THURSDAY...WITH SNOWFALL TAPERING OFF AT LAST ALONG THE DIVIDE BY THURSDAY EVENING. WITH TROUGH PASSAGE...SLIGHTLY BETTER MIXING SHOULD ERODE AT LEAST THE SOUTHERN AND WESTERN EDGE OF THE ARCTIC AIR...WITH AREAS ALONG THE EAST SLOPE OF THE SANGRES AND RATON MESA WARMING SOMEWHAT...THOUGH AGAIN SHADED COOLER THAN GUIDANCE. GFS NOW QUICKER THAN THE ECMWF BRINGING THE ARCTIC FRONT BACK SOUTH FRIDAY AFTERNOON...WITH EUROPEAN HOLDING IT BACK UNTIL FRIDAY NIGHT. WHILE GFS UPPER PATTERN IS PROBABLY TOO PROGRESSIVE...FASTER IS USUALLY BETTER WITH THE SOUTHWARD MOVEMENT OF ARCTIC AIR MASSES...SO WILL TEMPER WARM-UP ON FRIDAY...ESPECIALLY AREAS NORTH OF THE ARKANSAS RIVER. COLD AIR LOCKED INTO THE AREA BOTH SAT AND SUN...THOUGH SNOWFALL SHOULD BE LIMITED TO A FEW FLURRIES OVER THE EASTERN MOUNTAINS AND ALONG THE DIVIDE. && .AVIATION...MAIN CHALLENGE TONIGHT FOR THE REGION WILL BE THE POTENTIAL FOR FOG DEVELOPMENT AS THE SKIES CLEAR. BEST CHANCE FOR FOG WILL BE AT KALS AND KCOS...SO WILL INCLUDE IFR POTENTIAL IN THE TAFS. SNOW ONCE AGAIN WILL BEGIN ALONG THE CONTDVD BY 19Z MONDAY...WITH W-SW WINDS ACROSS THE HIGHER TERRAIN INCREASING AGAIN WITH GUSTS TO 45 MPH POSSIBLE. SNOWFALL IS EXPECTED TO BE ISOLATED IN NATURE FOR KCOS AND KPUB UNTIL TOMORROW NIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM NOON MONDAY TO 6 PM MST TUESDAY FOR COZ058>061-065>068. WINTER WEATHER ADVISORY FROM NOON MONDAY TO 6 PM MST TUESDAY FOR COZ062>064. && $$ 27/10 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 845 PM MST SAT DEC 13 2008 .830PM UPDATE...WIDESPREAD SNOWFALL OCCURRING NORTH OF THE ROAN TAVAPUTS WITH HIGHWAY 40 CLOSED FOR AWHILE THIS EVENING...HIGHWAY 13 REPORTED CLOSED AT 8PM BETWEEN RIFLE AND MEEKER. 6 INCHES REPORTED IN MEEKER AT 8PM. VERNAL HAS YET TO REPORT ANY SNOWFALL... BUT ENHANCEMENT IS APPROACHING THE UINTA BASIN. THE FRONT IS SLOW TO PUSH SOUTH OF THE ROAN-TAVAPUTS...SURPRISING CONSIDERING ITS STRENGTH AND DEPTH. FRONT PASSED GRAND JUNCTION AT 730 WITH SNOW STARTING AT 830. RIFLE TOO HAD A BIT OF DELAY BUT THEN G52MPH AND SNOW OCCURRED AT 820. THE COLD FRONT IS APPROACHING GATEWAY TO MONTROSE WITH LIGHTNING STRIKES OBSERVED SOUTH OF UNAWEEP CANYON. FRONTOGENETICAL FORCING IN THE 00Z RUC INDICATES THE FRONT WILL ADVANCE INTO SE UTAH FASTER OVER THE NEXT FEW HOURS WITH SLOWER PROGRESSION IN NW COLORADO. BY MIDNIGHT IT WILL BE ORIENTED FROM KREMMLING SW TO THE NW SAN JUAN MTNS. THEN IT IS PROGGED TO PUSH QUICKLY EAST BY 3AM WITH FRONTAL PASSAGE IN DURANGO-PAGOSA BY 5-6AM. MOST VALLEY LOCATIONS WILL HAVE ONLY LIGHT PRECIP UNTIL FRONTAL PASSAGE WHILE MOST MTNS WILL ACCUMULATE SNOW THROUGHOUT TONIGHT. WILL UPDATE FORECAST TO TRY TO REFLECT THIS SITUATION. && ...MAJOR WINTER STORM WILL IMPACT THE REGION THROUGH SUNDAY... ...ANOTHER STRONG STORM ARRIVES MONDAY AFTERNOON... .SHORT TERM...TONIGHT THROUGH MONDAY... SNOW MACHINE IS TURNING ON THE GUNS ACROSS WESTERN COLORADO AND EASTERN UTAH THIS AFTERNOON AS A STRONG PACIFIC STORM DROPS ACROSS THE GREAT BASIN. FAIRLY SIGNIFICANT WARM-UP OUT AHEAD OF THE COLD FRONT THIS AFTERNOON...WITH SEVERAL OF THE LOWER VALLEYS TOPPING 50 DEGREES. THIS WILL RESULT IN SOME AREAS OF RAIN UNTIL THE COLDER AIR ARRIVES WITH THE FRONT LATER THE EVENING. EXPECT PRECIPITATION TO CONTINUE TO INCREASE IN COVERAGE AND INTENSITY THIS EVENING...WITH THE ENTIRE CWA BECOMING ALL SNOW BY 10 PM. STRONG H3 JET WILL CONTINUE TO DROP SOUTH ACROSS THE FORECAST AREA AS ENERGY DIVES INTO THE GREAT BASIN FROM THE PACNW. THIS WILL KEEP STRONG DYNAMIC FORCING OVER THE REGION TONIGHT AND EARLY SUNDAY. MAIN TROUGH SLIDES THROUGH TONIGHT WITH VERY COLD AIRMASS SETTLING IN. CONDITIONS STABILIZE SOMEWHAT DURING THE DAY ON SUNDAY...SO INTENSITY OF SNOWFALL WILL DECREASE ALONG WITH COVERAGE DISSIPATING FROM WEST TO EAST AS THE AFTERNOON ROLLS ON. CURRENT HIGHLIGHTS REMAIN WELL PLACED AND AMOUNTS REMAIN REASONABLE...SO NO MAJOR ADJUSTMENTS FOR THIS STORM WITH MOUNTAINS AMOUNTS FROM 1 TO 3 FEET AND VALLEYS RANGING FROM 2 TO 12 INCHES. WILL MAKE SPECIAL NOTE THAT SEVERAL OF OUR SPOTTERS HAVE CALLED IN TODAY COMMENTING ABOUT PRESSURE READINGS BEING SOME OF THE LOWEST THEY HAVE RECORDED...WHICH FURTHER EMPHASIZES THE STRENGTH OF THE APPROACHING SYSTEM. SNOW IS EXPECTED TO TAPER OFF ENOUGH SUNDAY NIGHT WITH ENOUGH BREAKS IN THE CLOUD COVER TO RESULT IN THE COLDEST NIGHT OF THE SEASON SO FAR. THIS WILL ALSO ALLOW US TO DROP WINTER HIGHLIGHTS AS WE BRACE FOR THE NEXT SYSTEM SCHEDULED TO ROLL IN MONDAY AFTERNOON. THIS NEXT SYSTEM BEING ACCOMPANIED BY A 160+ KT JET WITH DEEP PACIFIC MOISTURE STREAMING INTO THE AREA. TARGETED AREA WILL BE OVER THE SOUTHERN MOUNTAINS AND CONFIDENCE CONTINUES TO INCREASE WITH THIS SOLUTION AS THE MODELS REMAIN IN GOOD AGREEMENT. AS A RESULT... HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE SOUTHERN MOUNTAINS STARTING MONDAY AFTERNOON AND CONTINUING THROUGH TUESDAY AFTERNOON. TEMPERATURES REMAIN COLD THROUGH THE PERIOD. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... UNSETTLED PATTERN THROUGH NEXT WEEKEND. UPPER LEVEL BROAD EXTENDS OVER THE NORTHERN AND CENTRAL ROCKIES MONDAY NIGHT. SHORTWAVE TRACKS THROUGH THE FLOW ASSOCIATED WITH STRONG JET OF 170KTS AT 250 MB OVER THE FOUR CORNERS REGION ACCORDING TO THE GFS. SFC WINDS WILL INCREASE AS THE JET MOVES OVERHEAD AND CAUSE BLOWING SNOW ESPECIALLY FOR THE SOUTHERN AND CENTRAL MOUNTAINS OF WESTERN COLORADO AND SOUTHEASTERN MOUNTAINS OF UTAH. FLOW TURNS TO THE SOUTHWEST MONDAY NIGHT HELPING TO BRING ADDITIONAL MOISTURE AS THE LOW PINCHES OFF. THE NORTHERN PORTION EXITS EAST OF THE NORTHERN ROCKIES BY EARLY WED. THE SOUTHERN PORTION CUTS OFF AND DIGS SOUTHWEST OVER THE GREAT BASIN AND THEN OUT ALONG THE CA COAST. THIS LOW WILL REVISIT THE FOUR CORNERS REGION AGAIN WEDNESDAY NIGHT INTO THURSDAY. INCREASED POPS DURING THIS TIME PERIOD ALTHOUGH CONFIDENCE NOT HIGH IN THE TIMING. SHOWERS LINGER OVER THE MOUNTAINS FRIDAY AND SATURDAY AS UPPER LEVEL GRADIENT REMAINS TIGHT AND A FEW WEAK EMBEDDED DISTURBANCES ARE NOTED IN THE MODELS. && .AVIATION... EXPECT MODERATE TO SEVERE TURBULENCE THROUGH TONIGHT AS 10,000 FOOT WINDS CONTINUE IN THE 50 TO 60 KNOT RANGE. EXPECT FAIRLY WIDESPREAD IFR CIGS AND VSBYS THROUGHOUT THE REGION BY 03Z THIS EVENING...WITH LITTLE IMPROVING UNTIL MIDDAY SUNDAY. EXPECT SOME IMPROVEMENT IN CEILINGS AND VSBYS OVER EASTERN UTAH AND EXTREME WESTERN COLORADO SUNDAY AFTERNOON. ANOTHER STRONG STORM MOVES INTO THE REGION ON MONDAY...BRINGING MORE SNOW AND WIND TO THE REGION. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...WINTER STORM WARNING THROUGH SUNDAY AFTERNOON...MOUNTAIN ZONES 3/4/9/10/12/13/17/18/19 AND VALLEY ZONES 2/5. WINTER STORM WARNING THROUGH SUNDAY AFTERNOON FOR THE INTERSTATE-70 CORRIDOR EAST OF NEW CASTLE...AND THE UPPER GUNNISON VALLEY...ZONES 8 AND 14. WINTER WEATHER ADVISORY THROUGH SUNDAY AFTERNOON FOR THE LOWER COLORADO VALLEYS...ZONES 1/6/7/11/20/21/22. WINTER STORM WATCH MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON FOR THE CENTRAL AND SOUTHWEST MOUNTAINS...ZONES 9/12/17/18/19. .UT...WINTER STORM WARNING THROUGH SUNDAY AFTERNOON...MOUNTAIN ZONES 23/25 AND 28. WINTER WEATHER ADVISORY THROUGH SUNDAY AFTERNOON FOR THE EASTERN UINTA BASIN...ZONE 24. WINTER STORM WATCH MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON FOR THE LA SAL AND ABAJO MOUNTAINS...ZONE 28. $$ UPDATE.........JOE SHORT TERM.....JDC LONG TERM......AS AVIATION.......JDC co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PUEBLO CO 904 AM MST SAT DEC 13 2008 .UPDATE... QUICK UPDATE TO THE FORECAST GRIDS TO START ALL HIGHLIGHTS RIGHT AWAY INSTEAD OF WAITING TO 18Z. 5 TO 8 INCHES OF SNOW HAS ALREADY BEEN REPORTED AT WOLF CREEK AND MONARCH SKI AREAS. && .PREV DISCUSSION... /ISSUED 436 AM MST SAT DEC 13 2008/ SHORT TERM... (TODAY AND TONIGHT) ..COMPLEX WEATHER PATTERN TODAY AND TONIGHT... ..HIGH RISK OF HAZARDOUS WINTER WEATHER CONTINENTAL DIVIDE... ..WINDY TO VERY WINDY MUCH OF SOUTHERN CO TODAY... CURRENTLY...PUB RADAR SHOWING "WIND SIGNATURE" ALONG THE LEE OF THE RAMPART RANGE...PIKES PEAK...WET MOUNTAINS...AND SOUTHERN SANGRE DE CRISTO MOUNTAINS. MOUNTAIN WAVE WIND EVENT BEGINNING TO TAKE SHAPE...THE BIGGEST QUESTION IS THE SEVERITY. SURFACE WINDS HAVE BEEN GUSTING TO 45-55KT ALONG THE RAMPART RANGE PER AIR FORCE ACADEMY SENSORS...BUT AIR FORCE ACADEMY AIRPORT IS LIGHT EASTERLY ALONG WITH THE COLORADO SPRINGS AIRPORT. MOUNTAIN WAVE ROTOR LIKELY GIVEN THE EASTERLY WINDS THAT DEVELOP FROM THE AIR FORCE ACADEMY AND COLORADO SPRINGS AIRPORT. MEANWHILE...FROM LA VETA PASS TO WALSENBURG(GAP FLOW) INCLUDING THE LEE OF THE SOUTHERN SANGRE DE CRISTO MOUNTAINS(MOUNTAIN WAVE)...WINDS HAVE BEEN GUSTING TO 30-40KTS. FURTHERMORE...THE HIGH TERRAIN MONARCH AWOS SENSOR HAS BEEN SUSTAINED AROUND 40KTS AND GUSTING 60KTS. QUITE THE TEMPERATURE CONTRAST IN THE WINDY AND NON-WINDY AREAS...ESPECIALLY ACROSS PUEBLO COUNTY...MID 20S AT PUEBLO AIRPORT AND 40S NEAR THE MOUNTAINS. NOT MUCH SNOW ACROSS WESTERN CO...BUT THAT WILL LIKELY SOON CHANGE. WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED THE NEXT UPPER LEVEL JET STREAK AND ASSOCIATED TROUGHS/MOISTURE DRIVING THROUGH THE GREAT BASIN...AND TAKING AIR ON CO EARLY THIS MORNING. TODAY...WELL ADVERTISED UPPER LEVEL 100-140KTS JET STREAK TO MOVE INTO CO LATER TODAY. SURFACE CYCLOGENESIS WILL LIKELY DEVELOP ACROSS SOUTHEASTERN WY WITH A LEE SIDE TROUGH EXTENDING ACROSS EASTERN CO PLAINS. THE BULLSEYE FOR QPF/SNOW AMOUNTS/POPS APPEARS TO BE AROUND THE CONTINENTAL DIVIDE GIVEN THE COMBINATION OF SYNOPTIC SCALE ASCENT AND FAVORED WEST-SOUTHWEST OROGRAPHIC FLOW LATER THIS AFTERNOON. SNOW...HEAVY AT TIMES...AND BLOWING SNOW WILL DEVELOP ACROSS THE CONTINENTAL DIVIDE THIS AFTERNOON. MEANWHILE...EAST OF THE CONTINENTAL DIVIDE...WINDY TO VERY WINDY CONDITIONS WILL PROBABLY BE THE MAIN FORECAST CONCERN TODAY. HAVE WIND GUSTS JUST BELOW WARNING CRITERIA FOR THE MOUNTAINS AND NON-MOUNTAINS GENERALLY ALONG AND WEST OF THE I-25 CORRIDOR. THERE IS A LOT OF WIND ALOFT AND WOULD NOT BE SURPRISED TO SEE A FEW WIND GUSTS TO AROUND 50KTS ACROSS THE SAN LUIS VALLEY...MOUNTAIN VALLEYS...AND WEST OF THE I-25. WARMER TEMPERATURES STILL LOOK ON TARGET FOR TODAY GIVEN THE INCREASED WIND SPEEDS. TONIGHT...RELATIVELY STRONG UPPER LEVEL JET STREAM TO REMAIN OVER MUCH OF CO. WINDY TO VERY WINDY CONDITIONS LIKELY ACROSS MUCH OF SOUTHERN CO TONIGHT...WHICH MAKES THE LOW TEMPERATURE FORECAST VERY PROBLEMATIC. LOW TEMPERATURES WILL LIKELY OCCUR AROUND 14Z/15Z TOMORROW MORNING...WHICH COULD TURN OUT TO BE TOMORROW`S HIGH TEMPERATURES. THUS...RELATIVELY WARM TEMPERATURES MAY ACTUALLY OCCUR MUCH OF THE NIGHT TONIGHT ACROSS SOUTHEASTERN CO. PERIODS OF SNOW AND AREAS OF BLOWING SNOW WILL CONTINUE AROUND THE CONTINENTAL DIVIDE. WILL ADD A WINTER WEATHER ADVISORY FOR ZONES 61/62/63/64/67. MODIFIED ARCTIC AIR MASS TO DROP INTO THE PALMER DIVIDE AND EAST CENTRAL CO AROUND 09Z-12Z/14. GFS HAS A LITTLE MORE QPF LATE TONIGHT ACROSS THE MOUNTAINS/HIGH VALLEYS INTO THE PALMER DIVIDE...SO WILL ADJUST FORECAST BASED ON THIS AND BOU`S ADJUSTMENTS FOR A FASTER SYSTEM. 17 LONG TERM... (SUNDAY THROUGH FRIDAY) HEAVY SNOW WILL CONTINUE THROUGH AT LEAST SUNDAY MORNING ACROSS THE WESTERN MTNS/HIGH VALLEYS AS DYNAMICS ASSOC WITH UPPER JET MOVING ACROSS NRN NM/SRN CO MOVES ACROSS THE AREA. LAPSE RATES STILL FAIRLY STEEP ACROSS THE MTS AND EXPECT CAA TO CONTINUE THROUGH THE DAY. BY AFTN...BEST DYNAMICS WILL BE MOVING INTO THE CENTRAL PLAINS...THOUGH THERE WILL STILL BE ENOUGH MOISTURE PINNED UP ALONG THE CONTDVD IN WESTERLY OROGRAPHIC FLOW TO KEEP HIGHER MTS ALONG THE CONTDVD SOCKED IN ALL DAY. ATTENTION TURNS TOWARDS ARCTIC FRONT WHICH WILL SURGE THROUGH THE SOUTHEAST PLAINS EARLY SUNDAY MORNING. IN FACT...HIGH TEMPS WILL LIKELY BE THE SAME AS THE LOW TEMPS FROM THE NIGHT BEFORE (OCCURRING AROUND 15Z) WITH TEMPS FALLING THROUGH THE AFTN. C51ENGE WILL BE SNOW POTENTIAL ACROSS THE PLAINS. FRONTOGENETICAL FORCING DURING THE MORNING SHOULD BE SUFFICIENT TO PRODUCE SCATTERED TO NUMEROUS SNOW SHOWERS ACROSS THE SE PLAINS...WITH BEST POTENTIAL LINGERING ALONG THE LOWER EASTERN SLOPES OF THE SE MTS/ADJACENT PLAINS IN S51OW POST FRONTAL UPSLOPE LAYER. FOR NOW...DO NOT THINK SNOWFALL WILL BE PARTICULARLY HEAVY ACROSS THE EASTERN MTS/ADJACENT PLAINS AS ISENTROPIC ANALYSIS SUGGESTS NEUTRAL BECOMING DOWNGLIDE BY THE AFTERNOON. HOWEVER THERE IS SOME INSTABILITY AND A BRIEF SHOT OF DYNAMICS IN THE MORNING AND WITH MODEL SOUNDINGS SATURATED THROUGH THE FAVORABLE DENDRITIC GROWTH ZONES -12 TO -18C RANGE...A FEW INCHES OF FLUFFY SNOW WILL BE POSSIBLE...ESPECIALLY UNDER THE HEAVIER SNOW BANDS. HAVE BUMPED UP POPS INTO THE LIKELY CATEGORY FOR THE EASTERN MTS/ADJACENT I-25 CORRIDOR. GUSTY NORTH WINDS BEHIND THE FRONT WILL MAKE FOR A RAW DAY ACROSS ALL OF THE SE PLAINS WITH WINTER MAKING A RATHER BRUTAL RE-APPEARANCE. TROF RELOADS IN THE WEST AS MORE ENERGY DROPS SOUTH OUT OF CANADA. THIS KEEPS COLD AND UNSETTLED CONDITIONS ACROSS THE AREA FOR SUNDAY NIGHT THROUGH MONDAY. NEXT PIECE OF ENERGY LIFTS OUT OF THE WESTERN US MEAN TROF LATE MONDAY AFTN/MONDAY NIGHT WITH SNOW INTENSIFYING ACROSS THE WRN MTS ONCE AGAIN. ANTICIPATE THAT WE WILL NEED ANOTHER WINTER STORM WATCH FOR MONDAY AFTN/MONDAY NIGHT ACROSS THE WESTERN MTS. MID LVL FLOW TURNS MORE SOUTHERLY AS UPPER JET APPROACHES MONDAY NIGHT AND SE PLAINS COMES UNDER A PERIOD OF ISENTROPIC UPGLIDE. THIS WILL SPREAD ANOTHER ROUND OF SNOW ACROSS THE EASTERN PLAINS MON NIGHT. WINDOW FOR SNOWFALL LOOKS FAIRLY BRIEF AS ENERGY SHOOTS OFF INT THE CENTRAL PLAINS BY EARLY TUES MORNING...SO NOT EXPECTING A HEAVY SNOW EVENT...BUT AGAIN WITH FAVORABLE TEMPS IN THE SATURATED LAYER...COULD SEE A COUPLE INCHES OF FLUFFY SNOW ACROSS PORTIONS OF THE ADJACENT PLAINS MONDAY NIGHT. UPPER JET AXIS SHIFTS NORTHWARD INTO CEN CO ON TUES WITH GFS SUGGESTING FRONTAL BOUNDARY WILL LIFT BACK NORTHWARD DURING THE DAY. SRN I-25 CORRIDOR COULD WARM BACK UP BUT THINK THE COLD AIR ACROSS THE PLAINS WILL HAVE A TOUGHER TIME ERODING BACK NORTH...EVEN BENEATH STRONG WESTERLY FLOW ALOFT. WILL KEEP TEMP GRIDS BELOW GUIDANCE VALUES FOR NOW. UNSETTLED CONDITIONS CONTINUE INTO WEDNESDAY NIGHT AS BOTH GFS/ECMWF KEEP TROF OVER THE WRN US. GFS IS QUICKEST TO WEAKEN THE TROF AND MOVE IT ACROSS THE AREA WED NIGHT...WHILE ECMWF HANGS ENERGY BACK OVER THE GREAT BASIN BEFORE MOVING IT ACROSS THE AREA ON THURSDAY. HOWEVER BOTH MODELS SUGGEST A TRANSITION TO WESTERLY FLOW BY NEXT WEEKEND WHICH SHOULD MEAN A TREND TOWARDS DRIER AND WARMER CONDITIONS WITH PERIODIC LIGHT SNOWS POSSIBLE ALONG THE CONTDVD REGION. -KT AVIATION... PER SHORT TERM DISCUSSION...WINDY TO VERY WINDY CONDITIONS WILL LIKELY DEVELOP FOR ALL TERMINAL FORECAST POINTS LATER THIS MORNING AND AFTERNOON. APPARENT ROTOR WILL BE AROUND KCOS THIS MORNING WITH THE WIND EXTREMELY VARIABLE SWITCHING FROM EASTERLY TO PERIOD WESTERLY GUSTY WINDS BACK TO EASTERLY. 17 && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 PM MST SUNDAY FOR COZ059-061>064- 067. WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR COZ058-060-066- 068. && $$ 27/10 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 436 AM MST SAT DEC 13 2008 .SHORT TERM... (TODAY AND TONIGHT) ...COMPLEX WEATHER PATTERN TODAY AND TONIGHT... ...HIGH RISK OF HAZARDOUS WINTER WEATHER CONTINENTAL DIVIDE... ...WINDY TO VERY WINDY MUCH OF SOUTHERN CO TODAY... CURRENTLY...PUB RADAR SHOWING "WIND SIGNATURE" ALONG THE LEE OF THE RAMPART RANGE...PIKES PEAK...WET MOUNTAINS...AND SOUTHERN SANGRE DE CRISTO MOUNTAINS. MOUNTAIN WAVE WIND EVENT BEGINNING TO TAKE SHAPE...THE BIGGEST QUESTION IS THE SEVERITY. SURFACE WINDS HAVE BEEN GUSTING TO 45-55KT ALONG THE RAMPART RANGE PER AIR FORCE ACADEMY SENSORS...BUT AIR FORCE ACADEMY AIRPORT IS LIGHT EASTERLY ALONG WITH THE COLORADO SPRINGS AIRPORT. MOUNTAIN WAVE ROTOR LIKELY GIVEN THE EASTERLY WINDS THAT DEVELOP FROM THE AIR FORCE ACADEMY AND COLORADO SPRINGS AIRPORT. MEANWHILE...FROM LA VETA PASS TO WALSENBURG(GAP FLOW) INCLUDING THE LEE OF THE SOUTHERN SANGRE DE CRISTO MOUNTAINS(MOUNTAIN WAVE)...WINDS HAVE BEEN GUSTING TO 30-40KTS. FURTHERMORE...THE HIGH TERRAIN MONARCH AWOS SENSOR HAS BEEN SUSTAINED AROUND 40KTS AND GUSTING 60KTS. QUITE THE TEMPERATURE CONTRAST IN THE WINDY AND NON-WINDY AREAS...ESPECIALLY ACROSS PUEBLO COUNTY...MID 20S AT PUEBLO AIRPORT AND 40S NEAR THE MOUNTAINS. NOT MUCH SNOW ACROSS WESTERN CO...BUT THAT WILL LIKELY SOON CHANGE. WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED THE NEXT UPPER LEVEL JET STREAK AND ASSOCIATED TROUGHS/MOISTURE DRIVING THROUGH THE GREAT BASIN...AND TAKING AIR ON CO EARLY THIS MORNING. TODAY...WELL ADVERTISED UPPER LEVEL 100-140KTS JET STREAK TO MOVE INTO CO LATER TODAY. SURFACE CYCLOGENESIS WILL LIKELY DEVELOP ACROSS SOUTHEASTERN WY WITH A LEE SIDE TROUGH EXTENDING ACROSS EASTERN CO PLAINS. THE BULLSEYE FOR QPF/SNOW AMOUNTS/POPS APPEARS TO BE AROUND THE CONTINENTAL DIVIDE GIVEN THE COMBINATION OF SYNOPTIC SCALE ASCENT AND FAVORED WEST-SOUTHWEST OROGRAPHIC FLOW LATER THIS AFTERNOON. SNOW...HEAVY AT TIMES...AND BLOWING SNOW WILL DEVELOP ACROSS THE CONTINENTAL DIVIDE THIS AFTERNOON. MEANWHILE...EAST OF THE CONTINENTAL DIVIDE...WINDY TO VERY WINDY CONDITIONS WILL PROBABLY BE THE MAIN FORECAST CONCERN TODAY. HAVE WIND GUSTS JUST BELOW WARNING CRITERIA FOR THE MOUNTAINS AND NON-MOUNTAINS GENERALLY ALONG AND WEST OF THE I-25 CORRIDOR. THERE IS A LOT OF WIND ALOFT AND WOULD NOT BE SURPRISED TO SEE A FEW WIND GUSTS TO AROUND 50KTS ACROSS THE SAN LUIS VALLEY...MOUNTAIN VALLEYS...AND WEST OF THE I-25. WARMER TEMPERATURES STILL LOOK ON TARGET FOR TODAY GIVEN THE INCREASED WIND SPEEDS. TONIGHT...RELATIVELY STRONG UPPER LEVEL JET STREAM TO REMAIN OVER MUCH OF CO. WINDY TO VERY WINDY CONDITIONS LIKELY ACROSS MUCH OF SOUTHERN CO TONIGHT...WHICH MAKES THE LOW TEMPERATURE FORECAST VERY PROBLEMATIC. LOW TEMPERATURES WILL LIKELY OCCUR AROUND 14Z/15Z TOMORROW MORNING...WHICH COULD TURN OUT TO BE TOMORROW`S HIGH TEMPERATURES. THUS...RELATIVELY WARM TEMPERATURES MAY ACTUALLY OCCUR MUCH OF THE NIGHT TONIGHT ACROSS SOUTHEASTERN CO. PERIODS OF SNOW AND AREAS OF BLOWING SNOW WILL CONTINUE AROUND THE CONTINENTAL DIVIDE. WILL ADD A WINTER WEATHER ADVISORY FOR ZONES 61/62/63/64/67. MODIFIED ARCTIC AIR MASS TO DROP INTO THE PALMER DIVIDE AND EAST CENTRAL CO AROUND 09Z-12Z/14. GFS HAS A LITTLE MORE QPF LATE TONIGHT ACROSS THE MOUNTAINS/HIGH VALLEYS INTO THE PALMER DIVIDE...SO WILL ADJUST FORECAST BASED ON THIS AND BOU`S ADJUSTMENTS FOR A FASTER SYSTEM. METZE .LONG TERM... (SUNDAY THROUGH FRIDAY) HEAVY SNOW WILL CONTINUE THROUGH AT LEAST SUNDAY MORNING ACROSS THE WESTERN MTNS/HIGH VALLEYS AS DYNAMICS ASSOC WITH UPPER JET MOVING ACROSS NRN NM/SRN CO MOVES ACROSS THE AREA. LAPSE RATES STILL FAIRLY STEEP ACROSS THE MTS AND EXPECT CAA TO CONTINUE THROUGH THE DAY. BY AFTN...BEST DYNAMICS WILL BE MOVING INTO THE CENTRAL PLAINS...THOUGH THERE WILL STILL BE ENOUGH MOISTURE PINNED UP ALONG THE CONTDVD IN WESTERLY OROGRAPHIC FLOW TO KEEP HIGHER MTS ALONG THE CONTDVD SOCKED IN ALL DAY. ATTENTION TURNS TOWARDS ARCTIC FRONT WHICH WILL SURGE THROUGH THE SOUTHEAST PLAINS EARLY SUNDAY MORNING. IN FACT...HIGH TEMPS WILL LIKELY BE THE SAME AS THE LOW TEMPS FROM THE NIGHT BEFORE (OCCURRING AROUND 15Z) WITH TEMPS FALLING THROUGH THE AFTN. CHALLENGE WILL BE SNOW POTENTIAL ACROSS THE PLAINS. FRONTOGENETICAL FORCING DURING THE MORNING SHOULD BE SUFFICIENT TO PRODUCE SCATTERED TO NUMEROUS SNOW SHOWERS ACROSS THE SE PLAINS...WITH BEST POTENTIAL LINGERING ALONG THE LOWER EASTERN SLOPES OF THE SE MTS/ADJACENT PLAINS IN SHALLOW POST FRONTAL UPSLOPE LAYER. FOR NOW...DO NOT THINK SNOWFALL WILL BE PARTICULARLY HEAVY ACROSS THE EASTERN MTS/ADJACENT PLAINS AS ISENTROPIC ANALYSIS SUGGESTS NEUTRAL BECOMING DOWNGLIDE BY THE AFTERNOON. HOWEVER THERE IS SOME INSTABILITY AND A BRIEF SHOT OF DYNAMICS IN THE MORNING AND WITH MODEL SOUNDINGS SATURATED THROUGH THE FAVORABLE DENDRITIC GROWTH ZONES -12 TO -18C RANGE...A FEW INCHES OF FLUFFY SNOW WILL BE POSSIBLE...ESPECIALLY UNDER THE HEAVIER SNOW BANDS. HAVE BUMPED UP POPS INTO THE LIKELY CATEGORY FOR THE EASTERN MTS/ADJACENT I-25 CORRIDOR. GUSTY NORTH WINDS BEHIND THE FRONT WILL MAKE FOR A RAW DAY ACROSS ALL OF THE SE PLAINS WITH WINTER MAKING A RATHER BRUTAL RE-APPEARANCE. TROF RELOADS IN THE WEST AS MORE ENERGY DROPS SOUTH OUT OF CANADA. THIS KEEPS COLD AND UNSETTLED CONDITIONS ACROSS THE AREA FOR SUNDAY NIGHT THROUGH MONDAY. NEXT PIECE OF ENERGY LIFTS OUT OF THE WESTERN US MEAN TROF LATE MONDAY AFTN/MONDAY NIGHT WITH SNOW INTENSIFYING ACROSS THE WRN MTS ONCE AGAIN. ANTICIPATE THAT WE WILL NEED ANOTHER WINTER STORM WATCH FOR MONDAY AFTN/MONDAY NIGHT ACROSS THE WESTERN MTS. MID LVL FLOW TURNS MORE SOUTHERLY AS UPPER JET APPROACHES MONDAY NIGHT AND SE PLAINS COMES UNDER A PERIOD OF ISENTROPIC UPGLIDE. THIS WILL SPREAD ANOTHER ROUND OF SNOW ACROSS THE EASTERN PLAINS MON NIGHT. WINDOW FOR SNOWFALL LOOKS FAIRLY BRIEF AS ENERGY SHOOTS OFF INT THE CENTRAL PLAINS BY EARLY TUES MORNING...SO NOT EXPECTING A HEAVY SNOW EVENT...BUT AGAIN WITH FAVORABLE TEMPS IN THE SATURATED LAYER...COULD SEE A COUPLE INCHES OF FLUFFY SNOW ACROSS PORTIONS OF THE ADJACENT PLAINS MONDAY NIGHT. UPPER JET AXIS SHIFTS NORTHWARD INTO CEN CO ON TUES WITH GFS SUGGESTING FRONTAL BOUNDARY WILL LIFT BACK NORTHWARD DURING THE DAY. SRN I-25 CORRIDOR COULD WARM BACK UP BUT THINK THE COLD AIR ACROSS THE PLAINS WILL HAVE A TOUGHER TIME ERODING BACK NORTH...EVEN BENEATH STRONG WESTERLY FLOW ALOFT. WILL KEEP TEMP GRIDS BELOW GUIDANCE VALUES FOR NOW. UNSETTLED CONDITIONS CONTINUE INTO WEDNESDAY NIGHT AS BOTH GFS/ECMWF KEEP TROF OVER THE WRN US. GFS IS QUICKEST TO WEAKEN THE TROF AND MOVE IT ACROSS THE AREA WED NIGHT...WHILE ECMWF HANGS ENERGY BACK OVER THE GREAT BASIN BEFORE MOVING IT ACROSS THE AREA ON THURSDAY. HOWEVER BOTH MODELS SUGGEST A TRANSITION TO WESTERLY FLOW BY NEXT WEEKEND WHICH SHOULD MEAN A TREND TOWARDS DRIER AND WARMER CONDITIONS WITH PERIODIC LIGHT SNOWS POSSIBLE ALONG THE CONTDVD REGION. -KT && .AVIATION... PER SHORT TERM DISCUSSION...WINDY TO VERY WINDY CONDITIONS WILL LIKELY DEVELOP FOR ALL TERMINAL FORECAST POINTS LATER THIS MORNING AND AFTERNOON. APPARENT ROTOR WILL BE AROUND KCOS THIS MORNING WITH THE WIND EXTREMELY VARIABLE SWITCHING FROM EASTERLY TO PERIOD WESTERLY GUSTY WINDS BACK TO EASTERLY. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 PM MST SUNDAY FOR COZ059-061>064-067. WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 PM MST SUNDAY FOR COZ058-060-066-068. && $$ 17/31 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1032 PM EST SUN DEC 14 2008 .SYNOPSIS... HIGH PRESSURE WILL WILL REMAIN WELL OFFSHORE OVERNIGHT. A COLD FRONT WILL HEAD INTO NEW ENGLAND MONDAY NIGHT AND MOVE OFF THE COAST TUESDAY. FAST MOVING LOW PRESSURE WILL MOVE ACROSS NEW ENGLAND WEDNESDAY INTO WEDNESDAY NIGHT...THEN A SECOND LOW MAY FOLLOW FOR FRIDAY. HIGH PRESSURE SHOULD RETURN NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A 4000 FOOT CLOUD LAYER SPREAD ACROSS CT-RI-SOUTHEAST MASS THIS EVENING WITH BROKEN TO OVERCAST ALTOCU ABOVE IT. EXPECT THESE CLOUDS TO LINGER THROUGH THE NIGHT WITH THE LOWER DECK POSSIBLY SPREADING NORTHEAST...ESPECIALLY IN EASTERN MASS. RADAR ECHOES ARE MAINLY MOVING FROM NORTHERN NY INTO VT-NH AND STAYING NORTH OF US. SO A MOSTLY CLOUDY DRY FORECAST IN THE CARDS FOR THE REMAINDER OF THE NIGHT. SOME ADJUSTMENTS TO OVERNIGHT TEMPS AND WINDS FROM THE 02Z RUC AND 00Z NAM...BUT THE OVERALL SONG REMAINS THE SAME FROM PAST EDITIONS. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... MONDAY...A COLD FRONT APPROACHES FROM THE WEST WITH A CHANCE OF SHOWERS ACROSS THE NORTHWEST ZONES DURING THE AFTERNOON. CLOUDS ARE EXPECTED TO PERSIST ESPECIALLY ACROSS INTERIOR SECTIONS. OTHERWISE A MILD DAY CAN BE EXPECTED ACROSS THE REGION. A WIND ADVISORY MAY BE NECESSARY ALONG THE SOUTH COAST BY AFTERNOON WHERE SUSTAINED WINDS WILL BE CLOSE TO THE MINIMUM THRESHOLD OF 27 KT. MONDAY NIGHT...SHOWERS LIKELY AS A COLD FRONT SWEEPS ACROSS THE REGION. SOME WET SNOW MAY MIX IN ACROSS THE NW INTERIOR BEFORE PRECIPITATION ENDS LATE. && .LONG TERM /TUESDAY THROUGH SUNDAY/... MODELS REMAIN IN GOOD AGREEMENT THROUGH WED BUT THEN DIVERGE SIGNIFICANTLY BY END OF WEEK. SO CONFIDENCE IS ABOVE AVERAGE EARLY IN PERIOD...THEN DROPS CONSIDERABLY BY FRI AND NEXT WEEKEND. BEYOND TUE...TWO SYSTEMS EXPECTED TO IMPACT SOUTHERN NEW ENGLAND... * LIGHT SNOW/ICING POSSIBLE INLAND WED MORNING BEFORE CHANGING TO RAIN * ANOTHER WINTRY MIX POSSIBLE INLAND LATE THU INTO FRI TUE - WED... COLD FRONT WILL BE MOVING OFFSHORE TUE. 12Z GFS REMAINS FASTER THAN 12Z NAM IN ENDING PRECIPITATION TUE AFTERNOON FROM N TO S...AND IT ALSO FARTHER S WITH FRONT AS HIGH PRESSURE OVER SOUTHERN CANADA IS A BIT STRONGER. DESPITE BEING PARALLEL TO UPPER FLOW AND PRESENCE OF RIDGE OFF MID ATLANTIC COAST...WE PREFER FASTER GFS SOLUTION WHICH HAS SUPPORT FROM BOTH SREFS AND GEFS. THEREFORE WE WILL MAINTAIN HIGHEST POPS TUE MORNING BEFORE INDICATING DRYING TREND LATER IN DAY. IT IS ALSO POSSIBLE THAT WE SEE PARTIAL CLEARING ACROSS SW NH BY DAYS END. PTYPE MAY BECOME AN ISSUE NORTH OF MASS PIKE AS COLDER AIR FILTERS IN. WE DO NOT EXPECT ANY ICING FROM SLEET OR FREEZING RAIN...BUT COLUMN SHOULD BECOME COLD ENOUGH TO SUPPORT SNOW SHOWERS. LITTLE IF ANY ACCUMULATION IS EXPECTED THOUGH. BASED UPON GFS AND SREF/GEFS...WE WILL BE IN BETWEEN SYSTEMS TUE NIGHT. PLENTY OF LOW LEVEL MOISTURE TO MAINTAIN CLOUDY SKIES AS FLOW SHIFTS TO NE...BUT THIS WILL ALSO REINFORCE COLDER AIR AT LOW LEVELS. BROUGHT CHANCE POPS IN TOWARD WED MORNING ACROSS CT VALLEY BUT ENSEMBLES SAY WE WILL REMAIN DRY PRIOR TO 12Z WED. PRECIPITATION WILL QUICKLY OVERSPREAD REGION WED MORNING. PLENTY OF WARMING OCCURS ALOFT WITH BROAD SW FLOW...HOWEVER WITH NE FLOW IN PLACE AT SURFACE IT WILL TAKE SOME TIME FOR COLD TO ERODE... ESPECIALLY AWAY FROM COAST. SREF DATA IS NOT HITTING FREEZING RAIN POTENTIAL VERY HARD INLAND...ASIDE FROM FAR WESTERN MA AND FAR SW NH BUT EVEN THERE PROBABILITIES ARE RELATIVELY LOW. WE THINK THERE WILL BE A FAIRLY RAPID TRANSITION FROM SNOW TO RAIN WED...STARTING FIRST ALONG COASTAL PLAIN IN MORNING THEN INLAND BY EARLY AFTERNOON. NOT LOOKING FOR SIGNIFICANT ICING AT THIS POINT BUT SOME LIGHT ICING IS POSSIBLE /UNDER 0.25 INCH/. ANY SNOWFALL SHOULD BE AN INCH OR TWO AT MOST. EVERYTHING WINDS DOWN WED EVENING AS SYSTEM HEADS OFFSHORE. THU - SAT... RELIED HEAVILY ON ENSEMBLES PER HPC REASONING. 12Z GFS REMAINS WAY TOO FAST IN BRINGING NEXT SYSTEM THROUGH NORTHEAST AND WE PREFER SLOWER 12Z ECMWF. ONCE PREVIOUS SYSTEM HEADS OFFSHORE THU...NEXT SURFACE LOW IS EXPECTED TO TRACK FROM LOWER GREAT LAKES FRI MORNING ACROSS CENTRAL NEW ENGLAND FRI AFTERNOON/EVENING...BEFORE REACHING MARITIMES SAT. THIS SCENARIO DOES NOT FAVOR MUCH IN WAY OF ACCUMULATING SNOWS... ESPECIALLY WITH SUCH WARM AIR ALOFT...BUT AGAIN WE WILL PROBABLY HAVE ENOUGH COLD TRAPPED AT LOW LEVELS ACROSS INTERIOR TO SUPPORT SNOW OR A WINTRY MIX AT ONSET LATE THU/EARLY FRI. SINCE LOW SHOULD TRACK TO OUR N FRI...WARMER AIR SHOULD EVENTUALLY WIN OUT AND FORCE A CHANGE TO RAIN IN ALL LOCATIONS. IN FACT GMOS SHOWS TEMPERATURES CLIMBING WELL INTO 40S AND 50S FRI AFTERNOON. FOLLOWING ENSEMBLE MEAN...DRY AND SEASONABLE WEATHER EXPECTED NEXT WEEKEND AS HIGH PRESSURE BUILDS INTO REGION. THERE IS LITTLE SUPPORT FOR STORMINESS ADVERTISED ON 12Z GFS FOR NEXT SUN. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... OVERNIGHT...3000 TO 4000 FOOT CEILINGS EXPECTED ALONG/SOUTH OF BAF- ORH-BOS OVERNIGHT. IFR CIGS SEEM LESS LIKELY AND WILL BE SCALED BACK. MONDAY...MVFR CEILINGS KBDL/KBAF/KORH/KMHT WITH SCATTERED SHOWERS AFTER 20Z. CEILINGS IMPROVE TO VFR KBOS/KPVD/KFMH/KHYA/KACK BEFORE LOWERING BACK TO MVFR AFTER 22Z. SW WINDS GUSTING TO 25-30KT MON AFTERNOON WITH STRONGEST WINDS NEAR S COAST. ALTHOUGH NOT MEETING LLWS CRITERIA...VERY STRONG SW WINDS /45-50KT/ EXPECTED NEAR 2KFT MOST OF DAY. MONDAY NIGHT...COLD FRONT CROSSES THE AREA. MVFR CEILINGS AND VSBYS IN -SHRA. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE...IFR IN RAIN SHOWERS IN THE MORNING...IMPROVING TO VFR FROM N-S DURING THE AFTERNOON. TUE NIGHT-WED...CONDITIONS LOWER TO MVFR-IFR CIGS/VSBYS IN AREAS OF RAIN AND SNOW. POSSIBLE FZRA/PL INTERIOR WED MORNING...THEN AGAIN WED EVENING BEFORE ENDING. THU AND FRI...MVFR/IFR POSSIBLE IN RAIN SHOWERS. SNOW OR A WINTRY MIX POSSIBLE INLAND AT START. && .MARINE... TONIGHT THROUGH MONDAY NIGHT...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR ALL OF THE COASTAL WATERS. SOUTHWEST WINDS EXPECTED TO GUST TO 25 TO 30 KT PARTICULARLY MONDAY AFTERNOON. WIND GUSTS COULD APPROACH 35 KT NEAR THE SOUTH COAST. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE...COLD FRONT CLEARS THE WATERS BY MIDDAY. EXPECT WIND SHIFT TO N-NW WITH GUSTS UP TO 25 KT...MAINLY ON THE OUTER WATERS. TUE NIGHT...WINDS SHIFT TO E-NE AND CONTINUE TO GUST UP TO 25 KT ON THE OUTER WATERS. WED...WINDS SHIFT AROUND TO S-SW AS WARM FRONT PUSHES THROUGH. GUSTS UP TO 25 KT CONTINUE...ESPECIALLY ON S COASTAL WATERS. THU AND FRI...WINDS SHOULD REMAIN BELOW 25 KT BUT SEAS ARE EXPECTED TO REMAIN ABOVE 5 FT. && .HYDROLOGY... MOST MAINSTEM RIVERS HAVE CRESTED AND WILL FALL SLOWLY THROUGH MON. THE CHARLES RIVER AT DOVER IS CRESTING OVERNIGHT NEAR FLOOD STAGE. WE HAVE ISSUED A FLOOD STATEMENT TO HEIGHTEN AWARENESS...BUT THE CREST DOES NOT SEEM HIGH ENOUGH TO JUSTIFY A WARNING. CONNECTICUT RIVER AT HARTFORD AND MIDDLETOWN WILL REMAIN IN FLOOD THROUGH AT LEAST TUE MORNING. ASSABET RIVER AT MAYNARD MA IS FORECAST TO FALL BELOW FLOOD STAGE LATER TONIGHT. RAINFALL LATE MON INTO TUE WILL AVERAGE 0.25 TO 0.50 INCH. THIS WOULD NOT CAUSE ADDITIONAL RISES ON RIVERS AND STREAMS...BUT RATHER SLOW THE RATE OF RECESSION. && .CLIMATE... DUE TO CONTINUED POWER OUTAGE AT WORCESTER THROUGH LATE SATURDAY MORNING...PART OF THE DAYS OBSERVATIONS WERE MISSING. SINCE WE HAVE NO BACKUP DATA AT THAT LOCATION...WE WENT WITH MISSING DATA FOR TEMPS AND WINDS ON THE DAILY CLIMATE REPORT. WITH HIGH PRESSURE OVERHEAD TODAY AND ALL OTHER STATIONS ACROSS THE REGION REPORTING NO PRECIP...LEFT A ZERO READING THERE AS WELL AS ZERO SNOW FOR 12/13. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ230>237-250- 254-255. && $$ SYNOPSIS...STRAUSS/JWD NEAR TERM...WTB SHORT TERM...WTB/STRAUSS LONG TERM...JWD AVIATION...STRAUSS/JWD MARINE...STRAUSS/JWD HYDROLOGY...WTB CLIMATE... ct AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TALLAHASSEE FL 305 PM EST SUN DEC 14 2008 ...UPDATED FOR CHANGE IN SMALL CRAFT ADVISORY STATUS... .SYNOPSIS/UPDATE... 20Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS GENERAL LONGWAVE TROUGHING ACROSS THE WESTERN CONUS WITH LONGWAVE RIDGING ALONG THE EASTERN SEABOARD. EMBEDDED WITHIN THE MAIN WESTERN TROUGH WE FIND A SERIES OF STRONG MID-LEVEL IMPULSES EJECTING OUT OF THE FOUR-CORNERS REGION AND INTO THE CENTRAL PLAINS/UPPER MIDWEST. ASSOCIATED WITH THE LEADING IMPULSE WE ARE FINDING A POTENT AREA OF LOW PRESSURE CURRENTLY OVER WESTERN WISCONSIN. IMPRESSIVE TEMPERATURE GRADIENT ASSOCIATED WITH THIS LOW ACROSS THE UPPER MIDWEST THIS AFTERNOON. MUCH OF WISCONSIN CURRENTLY IN THE UPPER 30S TO LOWER 40S ON THE EASTERN SIDE OF THE SYSTEM WHILE LOCATIONS BACK ACROSS MN ARE SEEING TEMPERATURES DROPPING THROUGH THE SINGLE DIGITS AND BELOW ZERO WITH STRONG NORTH FLOW AND BLIZZARD CONDITIONS UNDERWAY. CLOSER TO HOME...SOUTHERN STREAM FLOW IS RIDING NORTHEAST ACROSS MEXICO AND THEN ACROSS THE NORTHERN GULF COAST. NO LACK OF UPPER LEVEL MOISTURE SPREADING INTO THE SOUTHEAST WITH THIS FLOW. WE WILL CONTINUE TO SEE THIS PATTERN OVER THE NEXT DAY OR TWO WITH PERIODS OF MID/UPPER LEVEL CLOUDS...ESPECIALLY OVER THE WESTERN AND NORTHERN PORTIONS OF THE AREA. ANY SIGNIFICANT NORTHERN STREAM WEATHER WILL REMAIN FAR TO OUR NORTH. AT THE SURFACE...FORECAST AREA IS LOCATED IN REGION OF SOUTHEAST FLOW BETWEEN HIGH PRESSURE CENTERED OFF THE CAROLINA COAST AND A STRONG COLD FRONT RUNNING NORTH TO SOUTH THROUGH THE MIDDLE OF THE COUNTRY. THIS FLOW WILL CONTINUE INTO MONDAY BRINGING PLENTY OF LOW LEVEL MOISTURE INTO THE SOUTHEAST. SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)... THROUGH TONIGHT...CLOUDS HAVE DONE A GOOD JOB OF BREAKING UP TO PRODUCE A MIX OF SUN AND CLOUDS OVER THE WEST THIS AFTERNOON WITH THE BACK EDGE OF THE CLOUDS PULLING BACK TO THE EAST ACROSS THE APALACHICOLA RIVER. WILL BE INTERESTING TO SEE JUST HOW MUCH OF THIS LOWER TO MID-LEVEL CLOUD REDEVELOP DURING THE OVERNIGHT ACROSS THE WEST. THIS IS A TRICKY SKY FORECAST INTO MONDAY MORNING BUT WITH THE SOUTHEAST FLOW IN PLACE...WILL ONCE AGAIN GO WITH THE STRATUS DEVELOPMENT EVEN FOR PLACES THAT HAVE BROKEN OUT INTO SUN THIS AFTERNOON. AN AREA OF LOW LEVEL CONVERGENCE TO OUR WEST HAS RESULTED IN A FEW SHOWERS THROUGH THE DAY OVER TOWARD MOBILE. AS A WEAK MID-LEVEL SOUTHERN STREAM IMPULSE PROGGED BY THE GFS/NAM APPROACHES LATER TONIGHT THESE SCT SHOWERS MAY TRY TO MOVE A BIT FURTHER EAST AND HAVE A SLIGHT CHANCE POP GENERALLY WEST OF A LINE FROM PANAMA CITY TO DOTHAN AFTER MIDNIGHT. TRAILING SURFACE BOUNDARY FROM LOW PRESSURE PASSING THROUGH THE GREAT LAKES WILL APPROACH FROM THE NORTHWEST ON MONDAY. GUIDANCE IS UNANIMOUS IN SLOWING THE PROGRESS OF THIS BOUNDARY AS IT RUNS INTO A STRONG MID/UPPER LEVEL RIDGE IN PLACE ACROSS THE GULF OF MEXICO. THIS FRONT IS THEN FORECAST TO STALL JUST OUTSIDE OF OUR WESTERN AND NORTHERN ZONES LATER MONDAY INTO TUESDAY. CAN NOT RULE OUT A FEW SHOWERS DURING THIS TIME FRAME AS THE LOW LEVEL FOCUS OF THE FRONT COMBINES WITH THE CONTINUED SERIES OF MID-LEVEL IMPULSES RIDING THE SOUTHERN STREAM. THE ORIENTATION OF THE IMPULSES SUGGEST THE BEST CHANCES TO SEE A PASSING SHOWER OR TWO WOULD BE ACROSS WALTON COUNTY INTO SOUTHEAST ALABAMA. HOWEVER...ANY RAINFALL WILL NOT BE A BIG DEAL WITH VERY LITTLE IN THE WAY OF ACCUMULATION AND WILL KEEP POPS LOW. NOT ANTICIPATING ANY TYPE OF RAINFALL THAT WOULD HAVE AN ADDITIONAL IMPACT ON THE RIVERS THAT ARE CURRENTLY AT OR NEAR FLOOD STAGE ACROSS THE WESTERN/NORTHERN ZONES. TUESDAY INTO EARLY WEDNESDAY WILL BE WATCHING A STRONG PIECE OF UPPER LEVEL ENERGY DIVING SOUTH ALONG THE COAST OF CALIFORNIA. THIS WILL RESULT IN AN AMPLIFICATION OF THE WESTERN CONUS TROUGH. IN RESPONSE...SHOULD SEE AN AMPLIFICATION OF THE MID-LEVEL RIDGING TO OUR SOUTH UP INTO THE CENTRAL AND NORTHEAST GULF COAST. OLD FRONTAL BOUNDARY TO OUR NORTHWEST WILL THEN RETREAT BACK NORTH INTO THE TENNESSEE VALLEY...TAKING THE BEST FOCUS FOR ANY SCATTERED SHOWERS WITH IT. THE OVERALL PATTERN ACROSS THE GULF AND OUR FORECAST AREA BY THE END OF THE SHORT-TERM PERIOD IS TAKING ON ALMOST A SUMMER-LIKE APPEARANCE WITH A STRONG 590DM H5 RIDGE BUILDING OVERHEAD AND SURFACE RIDGING PUSHING BACK ACROSS THE NORTHERN HALF OF THE FL PENINSULA. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL REMAIN ABOVE NORMAL. TONIGHT WILL SEE TEMPS GENERALLY IN THE LOWER 50S INLAND AND THE MIDDLE TO UPPER 50S ALONG THE IMMEDIATE COAST. MONDAY NIGHT AND TUESDAY NIGHT SHOULD EVEN EDGE UP A FEW MORE DEGREES. HIGH TEMPERATURES TOMORROW RANGING FROM THE UPPER 60S TO NEAR 70 FAR NORTHWEST AND THE LOWER TO MIDDLE 70S ELSEWHERE. ONLY OTHER EXCEPTION WOULD BE ALONG THE IMMEDIATE COASTS OF FRANKLIN AND WAKULLA COUNTIES WHERE THE FLOW OFF THE RELATIVELY COOLER WATERS OF APALACHEE BAY WILL HOLD TEMPS BACK IN THE UPPER 60S. WIDESPREAD MIDDLE 70S ARE THEN ANTICIPATED FOR TUESDAY AFTERNOON AWAY FROM THE COAST. && .LONG TERM (WEDNESDAY THROUGH SUNDAY)...DEEP LAYER RIDGE WILL BE THE MAIN WX PLAYER THROUGH MUCH OF THE EXTENDED PERIOD. AS THE RIDGE AMPLIFIES WEDNESDAY AND THURSDAY...ATMOSPHERE SHOULD DRY OUT AND WARM UP WITH TEMPERATURES EXPECTED TO APPROACH 80 DEGREES AWAY FROM THE IMMEDIATE COAST. THE RIDGE WILL BEGIN TO WEAKEN ON FRIDAY AS A LONG WAVE TROUGH DEEPENS OVER THE CENTRAL PART OF THE COUNTRY. LONG RANGE GUIDANCE IN GOOD AGREEMENT ON PUSHING A MOISTURE STARVED FRONT THROUGH THE REGION SOMETIME LATE SATURDAY OR EARLY SUNDAY. A COOLER AIR MASS WILL PUSH IN BEHIND THE FRONT FOR SUNDAY WITH TEMPERATURES DROPPING BACK BELOW CLIMO. && .MARINE... FAIRLY TIGHT PRESSURE GRADIENT CONTINUES THROUGH THE OVERNIGHT BETWEEN HIGH PRESSURE WELL TO OUR NORTHEAST AND A SLOWLY APPROACHING FRONT WELL TO OUR WEST. ADVISORY LEVEL WINDS ARE SLOWLY SUBSIDING ACROSS THE WESTERN MARINE ZONES...HOWEVER SEAS ARE SLOWER TO RESPOND AND WILL EXTEND THE SMALL CRAFT ADVISORY FOR THE WESTERN LEGS INTO THE MIDDLE EVENING HOURS. HOWEVER...BOATERS SHOULD STILL EXERCISE CAUTION ACROSS ALL MARINE ZONES AS WIND AND SEAS REMAIN ELEVATED INTO MONDAY MORNING. THE HIGH CENTER WEAKENS TO OUR NORTHEAST DURING MONDAY ALLOWING THE GRADIENT TO BEGIN TO RELAX. SHOULD SEE WINDS AND SEAS FALL BELOW HEADLINE CRITERIA DURING MONDAY...AND THEN REMAIN LOW INTO THE MIDDLE PORTION OF THE WEEK AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NORTHEAST GULF OF MEXICO. && .AVIATION... LOWERING CEILINGS TONIGHT AS MORE WARM AND MOIST AIR STREAMS IN FROM THE SOUTHEAST. EXPECT MVFR CIGS BY LATE EVENING AND IFR CIGS AND VISBY BY EARLY MORNING ALL TERMINALS. && .FIRE WX... WITH SOUTHEAST TO SOUTH WIND FLOW OVER NEXT SEVERAL DAYS THERE WILL BE ENOUGH MOISTURE IN THE LOWER ATMOSPHERE TO KEEP RH LEVELS WELL OUT OF CRITICAL RANGE. A SLIGHT CHANCE OF RAIN OR SHOWERS WILL BE SEEN THROUGH TUESDAY. && .HYDROLOGY... RESIDENTS LIVING ALONG THE MANY SWOLLEN RIVERS ACROSS THE WESTERN AND NORTHERN FORECAST AREA SHOULD CONTINUE TO MONITOR THE RIVERS AND LAKES AHPS WEB PAGE (HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=TAE) FOR THE LATEST RIVER STAGES AND FORECASTS. THE LATEST FLOOD WARNINGS AND FLOOD STATEMENTS CAN ALSO BE FOUND AT THIS SITE AND ON NOAA WEATHER RADIO. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 52 74 55 75 56 / 10 15 10 10 10 PANAMA CITY 58 72 59 73 61 / 10 25 10 10 10 DOTHAN 52 70 55 74 58 / 20 30 10 20 20 ALBANY 50 72 54 75 57 / 10 20 10 10 10 VALDOSTA 52 74 54 75 55 / 10 15 10 10 10 CROSS CITY 52 77 54 78 55 / 10 15 10 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR THE FOLLOWING ZONES: COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WEATHER...GOREE LONG TERM...CAMP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 305 PM EST SUN DEC 14 2008 .SYNOPSIS/UPDATE... 20Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS GENERAL LONGWAVE TROUGHING ACROSS THE WESTERN CONUS WITH LONGWAVE RIDGING ALONG THE EASTERN SEABOARD. EMBEDDED WITHIN THE MAIN WESTERN TROUGH WE FIND A SERIES OF STRONG MID-LEVEL IMPULSES EJECTING OUT OF THE FOUR-CORNERS REGION AND INTO THE CENTRAL PLAINS/UPPER MIDWEST. ASSOCIATED WITH THE LEADING IMPULSE WE ARE FINDING A POTENT AREA OF LOW PRESSURE CURRENTLY OVER WESTERN WISCONSIN. IMPRESSIVE TEMPERATURE GRADIENT ASSOCIATED WITH THIS LOW ACROSS THE UPPER MIDWEST THIS AFTERNOON. MUCH OF WISCONSIN CURRENTLY IN THE UPPER 30S TO LOWER 40S ON THE EASTERN SIDE OF THE SYSTEM WHILE LOCATIONS BACK ACROSS MN ARE SEEING TEMPERATURES DROPPING THROUGH THE SINGLE DIGITS AND BELOW ZERO WITH STRONG NORTH FLOW AND BLIZZARD CONDITIONS UNDERWAY. CLOSER TO HOME...SOUTHERN STREAM FLOW IS RIDING NORTHEAST ACROSS MEXICO AND THEN ACROSS THE NORTHERN GULF COAST. NO LACK OF UPPER LEVEL MOISTURE SPREADING INTO THE SOUTHEAST WITH THIS FLOW. WE WILL CONTINUE TO SEE THIS PATTERN OVER THE NEXT DAY OR TWO WITH PERIODS OF MID/UPPER LEVEL CLOUDS...ESPECIALLY OVER THE WESTERN AND NORTHERN PORTIONS OF THE AREA. ANY SIGNIFICANT NORTHERN STREAM WEATHER WILL REMAIN FAR TO OUR NORTH. AT THE SURFACE...FORECAST AREA IS LOCATED IN REGION OF SOUTHEAST FLOW BETWEEN HIGH PRESSURE CENTERED OFF THE CAROLINA COAST AND A STRONG COLD FRONT RUNNING NORTH TO SOUTH THROUGH THE MIDDLE OF THE COUNTRY. THIS FLOW WILL CONTINUE INTO MONDAY BRINGING PLENTY OF LOW LEVEL MOISTURE INTO THE SOUTHEAST. SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)... THROUGH TONIGHT...CLOUDS HAVE DONE A GOOD JOB OF BREAKING UP TO PRODUCE A MIX OF SUN AND CLOUDS OVER THE WEST THIS AFTERNOON WITH THE BACK EDGE OF THE CLOUDS PULLING BACK TO THE EAST ACROSS THE APALACHICOLA RIVER. WILL BE INTERESTING TO SEE JUST HOW MUCH OF THIS LOWER TO MID-LEVEL CLOUD REDEVELOP DURING THE OVERNIGHT ACROSS THE WEST. THIS IS A TRICKY SKY FORECAST INTO MONDAY MORNING BUT WITH THE SOUTHEAST FLOW IN PLACE...WILL ONCE AGAIN GO WITH THE STRATUS DEVELOPMENT EVEN FOR PLACES THAT HAVE BROKEN OUT INTO SUN THIS AFTERNOON. AN AREA OF LOW LEVEL CONVERGENCE TO OUR WEST HAS RESULTED IN A FEW SHOWERS THROUGH THE DAY OVER TOWARD MOBILE. AS A WEAK MID-LEVEL SOUTHERN STREAM IMPULSE PROGGED BY THE GFS/NAM APPROACHES LATER TONIGHT THESE SCT SHOWERS MAY TRY TO MOVE A BIT FURTHER EAST AND HAVE A SLIGHT CHANCE POP GENERALLY WEST OF A LINE FROM PANAMA CITY TO DOTHAN AFTER MIDNIGHT. TRAILING SURFACE BOUNDARY FROM LOW PRESSURE PASSING THROUGH THE GREAT LAKES WILL APPROACH FROM THE NORTHWEST ON MONDAY. GUIDANCE IS UNANIMOUS IN SLOWING THE PROGRESS OF THIS BOUNDARY AS IT RUNS INTO A STRONG MID/UPPER LEVEL RIDGE IN PLACE ACROSS THE GULF OF MEXICO. THIS FRONT IS THEN FORECAST TO STALL JUST OUTSIDE OF OUR WESTERN AND NORTHERN ZONES LATER MONDAY INTO TUESDAY. CAN NOT RULE OUT A FEW SHOWERS DURING THIS TIME FRAME AS THE LOW LEVEL FOCUS OF THE FRONT COMBINES WITH THE CONTINUED SERIES OF MID-LEVEL IMPULSES RIDING THE SOUTHERN STREAM. THE ORIENTATION OF THE IMPULSES SUGGEST THE BEST CHANCES TO SEE A PASSING SHOWER OR TWO WOULD BE ACROSS WALTON COUNTY INTO SOUTHEAST ALABAMA. HOWEVER...ANY RAINFALL WILL NOT BE A BIG DEAL WITH VERY LITTLE IN THE WAY OF ACCUMULATION AND WILL KEEP POPS LOW. NOT ANTICIPATING ANY TYPE OF RAINFALL THAT WOULD HAVE AN ADDITIONAL IMPACT ON THE RIVERS THAT ARE CURRENTLY AT OR NEAR FLOOD STAGE ACROSS THE WESTERN/NORTHERN ZONES. TUESDAY INTO EARLY WEDNESDAY WILL BE WATCHING A STRONG PIECE OF UPPER LEVEL ENERGY DIVING SOUTH ALONG THE COAST OF CALIFORNIA. THIS WILL RESULT IN AN AMPLIFICATION OF THE WESTERN CONUS TROUGH. IN RESPONSE...SHOULD SEE AN AMPLIFICATION OF THE MID-LEVEL RIDGING TO OUR SOUTH UP INTO THE CENTRAL AND NORTHEAST GULF COAST. OLD FRONTAL BOUNDARY TO OUR NORTHWEST WILL THEN RETREAT BACK NORTH INTO THE TENNESSEE VALLEY...TAKING THE BEST FOCUS FOR ANY SCATTERED SHOWERS WITH IT. THE OVERALL PATTERN ACROSS THE GULF AND OUR FORECAST AREA BY THE END OF THE SHORT-TERM PERIOD IS TAKING ON ALMOST A SUMMER-LIKE APPEARANCE WITH A STRONG 590DM H5 RIDGE BUILDING OVERHEAD AND SURFACE RIDGING PUSHING BACK ACROSS THE NORTHERN HALF OF THE FL PENINSULA. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL REMAIN ABOVE NORMAL. TONIGHT WILL SEE TEMPS GENERALLY IN THE LOWER 50S INLAND AND THE MIDDLE TO UPPER 50S ALONG THE IMMEDIATE COAST. MONDAY NIGHT AND TUESDAY NIGHT SHOULD EVEN EDGE UP A FEW MORE DEGREES. HIGH TEMPERATURES TOMORROW RANGING FROM THE UPPER 60S TO NEAR 70 FAR NORTHWEST AND THE LOWER TO MIDDLE 70S ELSEWHERE. ONLY OTHER EXCEPTION WOULD BE ALONG THE IMMEDIATE COASTS OF FRANKLIN AND WAKULLA COUNTIES WHERE THE FLOW OFF THE RELATIVELY COOLER WATERS OF APALACHEE BAY WILL HOLD TEMPS BACK IN THE UPPER 60S. WIDESPREAD MIDDLE 70S ARE THEN ANTICIPATED FOR TUESDAY AFTERNOON AWAY FROM THE COAST. && .LONG TERM (WEDNESDAY THROUGH SUNDAY)...DEEP LAYER RIDGE WILL BE THE MAIN WX PLAYER THROUGH MUCH OF THE EXTENDED PERIOD. AS THE RIDGE AMPLIFIES WEDNESDAY AND THURSDAY...ATMOSPHERE SHOULD DRY OUT AND WARM UP WITH TEMPERATURES EXPECTED TO APPROACH 80 DEGREES AWAY FROM THE IMMEDIATE COAST. THE RIDGE WILL BEGIN TO WEAKEN ON FRIDAY AS A LONG WAVE TROUGH DEEPENS OVER THE CENTRAL PART OF THE COUNTRY. LONG RANGE GUIDANCE IN GOOD AGREEMENT ON PUSHING A MOISTURE STARVED FRONT THROUGH THE REGION SOMETIME LATE SATURDAY OR EARLY SUNDAY. A COOLER AIR MASS WILL PUSH IN BEHIND THE FRONT FOR SUNDAY WITH TEMPERATURES DROPPING BACK BELOW CLIMO. && .MARINE... FAIRLY TIGHT PRESSURE GRADIENT CONTINUES THROUGH THE OVERNIGHT BETWEEN HIGH PRESSURE WELL TO OUR NORTHEAST AND A SLOWLY APPROACHING FRONT WELL TO OUR WEST. ADVISORY LEVEL WINDS AND SEAS ARE SLOWLY SUBSIDING ACROSS THE WESTERN MARINE ZONES AND WILL ALLOW THE CURRENT ADVISORY TO EXPIRE AT 4 PM. HOWEVER...BOATERS SHOULD STILL EXERCISE CAUTION ACROSS ALL MARINE ZONES AS WIND AND SEAS REMAIN ELEVATED INTO MONDAY MORNING. THE HIGH CENTER WEAKENS TO OUR NORTHEAST DURING MONDAY ALLOWING THE GRADIENT TO BEGIN TO RELAX. SHOULD SEE WINDS AND SEAS FALL BELOW HEADLINE CRITERIA DURING MONDAY...AND THEN REMAIN LOW INTO THE MIDDLE PORTION OF THE WEEK AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NORTHEAST GULF OF MEXICO. && .AVIATION... LOWERING CEILINGS TONIGHT AS MORE WARM AND MOIST AIR STREAMS IN FROM THE SOUTHEAST. EXPECT MVFR CIGS BY LATE EVENING AND IFR CIGS AND VISBY BY EARLY MORNING ALL TERMINALS. && .FIRE WX... WITH SOUTHEAST TO SOUTH WIND FLOW OVER NEXT SEVERAL DAYS THERE WILL BE ENOUGH MOISTURE IN THE LOWER ATMOSPHERE TO KEEP RH LEVELS WELL OUT OF CRITICAL RANGE. A SLIGHT CHANCE OF RAIN OR SHOWERS WILL BE SEEN THROUGH TUESDAY. && .HYDROLOGY... RESIDENTS LIVING ALONG THE MANY SWOLLEN RIVERS ACROSS THE WESTERN AND NORTHERN FORECAST AREA SHOULD CONTINUE TO MONITOR THE RIVERS AND LAKES AHPS WEB PAGE (HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=TAE) FOR THE LATEST RIVER STAGES AND FORECASTS. THE LATEST FLOOD WARNINGS AND FLOOD STATEMENTS CAN ALSO BE FOUND AT THIS SITE AND ON NOAA WEATHER RADIO. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 52 74 55 75 56 / 10 15 10 10 10 PANAMA CITY 58 72 59 73 61 / 10 25 10 10 10 DOTHAN 52 70 55 74 58 / 20 30 10 20 20 ALBANY 50 72 54 75 57 / 10 20 10 10 10 VALDOSTA 52 74 54 75 55 / 10 15 10 10 10 CROSS CITY 52 77 54 78 55 / 10 15 10 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WEATHER...GOREE LONG TERM...CAMP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 1045 AM EST SUN DEC 14 2008 .SYNOPSIS/UPDATE... 15Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS GENERAL LONGWAVE TROUGHING ACROSS THE WESTERN CONUS THIS MORNING WITH LONGWAVE RIDGING ALONG THE EASTERN SEABOARD. EMBEDDED WITHIN THE MAIN WESTERN TROUGH WE FIND A SERIES OF STRONG MID-LEVEL IMPULSES EJECTING OUT OF THE FOUR-CORNERS REGION AND INTO THE CENTRAL PLAINS/UPPER MIDWEST. ASSOCIATED WITH THE LEADING IMPULSE WE ARE FINDING A POTENT AREA OF LOW PRESSURE CURRENTLY OVER SOUTHERN MINNESOTA. IMPRESSIVE TEMPERATURE GRADIENT ASSOCIATED WITH THIS LOW ACROSS THE UPPER MIDWEST. SOUTHEAST MINNESOTA CURRENTLY RISING THROUGH THE LOWER 40S ON THE EASTERN SIDE OF THE SYSTEM WHILE WEST-CENTRAL PORTION OF THE STATE ARE SEEING TEMPERATURES DROP BELOW ZERO WITH STRONG NORTH FLOW AND BLIZZARD CONDITIONS UNDERWAY. CLOSER TO HOME...SOUTHERN STREAM FLOW IS RIDING NORTHEAST ACROSS MEXICO AND THEN ACROSS THE NORTHERN GULF COAST THIS MORNING. NO LACK OF UPPER LEVEL MOISTURE SPREADING INTO THE SOUTHEAST WITH THIS FLOW. WE WILL CONTINUE TO SEE THIS PATTERN OVER THE NEXT DAY OR TWO WITH ANY SIGNIFICANT NORTHERN STREAM WEATHER REMAINING FAR TO OUR NORTH. AT THE SURFACE...FORECAST AREA IS LOCATED IN EAST TO SOUTHEAST FLOW BETWEEN HIGH PRESSURE CENTERED OFF THE CAROLINA COAST AND THE SYSTEM ACROSS THE CENTRAL PORTION OF THE COUNTRY. THIS FLOW WILL CONTINUE INTO TONIGHT BRINGING PLENTY OF LOW LEVEL MOISTURE INTO THE SOUTHEAST. LATEST 12Z KTLH SOUNDING SHOWED ABUNDANT LOW LEVEL MOISTURE TRAPPED UNDER 800MB RESULTING IN THE WIDESPREAD CLOUD DECK BETWEEN 5 AND 7 KFT. ABOVE 800MB THE AIRMASS IS QUITE DRY AND STABLE. DIFFICULT TO SAY JUST HOW MUCH DISSIPATION OF THESE CLOUDS WE WILL SEE THROUGH THE DAY. WOULD NOT BE SURPRISED TO SEE A FEW BREAKS OF SUN INTO THE AFTERNOON HOURS...HOWEVER WITH THE RELATIVELY WEAKER DECEMBER SUN AND THE CONTINUED SUPPLY OF MOISTURE...WILL MAINTAIN A FORECAST OF MOSTLY CLOUDY CONDITIONS THROUGH THE DAY. THE MOIST SOUTHEAST FLOW WITH SOME LIFT FROM A WEAK SOUTHERN STREAM DISTURBANCE IS RESULTING IN A FEW SHOWERS THIS MORNING FROM NEAR PENSACOLA TO MOBILE. NOT EXPECTING ANYTHING MORE THAN A FEW PASSING SPRINKLES ACROSS OUR PANHANDLE ZONES INTO THE AFTERNOON HOURS WITH REALLY NO IMPACT TO ANY OUTDOOR ACTIVITIES EXPECTED. NOT GOING TO MAKE ANY ADJUSTMENTS TO THE TEMPERATURE GRIDS YET...BUT IF THE CLOUDS HOLD THROUGH THE DAY MAY COME UP A FEW DEGREES SHORT ON HIGHS. TRAILING SURFACE BOUNDARY FROM LOW PRESSURE PASSING THROUGH THE GREAT LAKES WILL APPROACH FROM THE NORTHWEST INTO MONDAY. GUIDANCE IS UNANIMOUS IN SLOWING THIS BOUNDARY AS IT MOVES INTO THE SOUTHEAST AND THEN STALLING THE FRONT JUST OUTSIDE OF OUR WESTERN AND NORTHERN ZONES LATER MONDAY INTO TUESDAY. CAN NOT RULE OUT A FEW SHOWERS DURING THIS TIME FRAME AS THE LOW LEVEL FOCUS OF THE FRONT COMBINES WITH THE CONTINUED SERIES OF MID-LEVEL IMPULSES RIDING THE SOUTHERN STREAM. HOWEVER...THESE WILL NOT BE A BIG DEAL WITH VERY LITTLE IN THE WAY OF ACCUMULATION AND WILL KEEP POPS LOW. CERTAINLY NOT EXPECTING ENOUGH TO HAVE AN IMPACT ON THE RIVERS NEAR OR AT FLOOD ACROSS THE WESTERN/NORTHERN ZONES. && .MARINE... EASTERN ZONES...WINDS AND SEAS HAVE DIMINISHED BELOW ADVISORY LEVELS ACROSS THE EASTERN MARINE ZONES LATE THIS MORNING. HOWEVER...SMALL CRAFT OPERATORS SHOULD CONTINUE TO EXERCISE CAUTION INTO THE OVERNIGHT HOURS BEFORE WINDS AND SEAS DIMINISH BELOW HEADLINE CRITERIA MONDAY. WESTERN ZONES...ADVISORY LEVEL WINDS WILL DIMINISH TO CAUTIONARY LEVELS DURING THE AFTERNOON HOURS. HOWEVER...ADVISORY LEVEL SEAS ARE ANTICIPATED TO HOLD FOR MUCH OF THE AFTERNOON...ESPECIALLY WELL OFFSHORE. FOR THESE REASONS THE SMALL CRAFT ADVISORY FOR THE WESTERN MARINE ZONES HAS BEEN EXTENDED UNTIL 4 PM EST THIS AFTERNOON. ONCE THE ADVISORY HAS EXPIRED LATER THIS AFTERNOON...SMALL CRAFT OPERATORS SHOULD CONTINUE TO EXERCISE CAUTION AS ELEVATED WINDS AND SEAS ARE EXPECTED TO HOLD THROUGH THE OVERNIGHT HOURS. && .AVIATION... 12Z TLH SOUNDING MEASURED SOUTHEAST WIND WIND FROM SURFACE TO 6 KFT WITH CLOUD DECK AT BASE OF INVERSION AT 6KFT. THIS INVERSION SHOULD LOWER WITH TIME TODAY AND TONIGHT AND LOWERING CEILINGS TO MVFR CRITERIA ARE FORECAST FOR TONIGHT. THIS TREND CONTINUES WITH IFR CIG AND VIS POSSIBLE DURING EARLY MORNING WITH GRADUAL IMPROVEMENT AFTER SUNRISE. && .FIRE WX... MOIST EAST TO SOUTHEAST LOW LEVEL FLOW WILL KEEP RH VALUES WELL ABOVE CRITICAL LEVELS THROUGH THE NEXT SEVERAL DAYS. && .HYDROLOGY... RESIDENTS LIVING ALONG THE MANY SWOLLEN RIVERS ACROSS THE WESTERN AND NORTHERN FORECAST AREA SHOULD CONTINUE TO MONITOR THE RIVERS AND LAKES AHPS WEB PAGE (HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=TAE) FOR THE LATEST RIVER STAGES AND FORECASTS. THE LATEST FLOOD WARNINGS AND FLOOD STATEMENTS CAN ALSO BE FOUND AT THIS SITE AND ON NOAA WEATHER RADIO. .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 66 51 74 57 76 / 10 10 20 20 20 PANAMA CITY 68 56 74 60 76 / 10 10 20 20 20 DOTHAN 63 53 69 57 75 / 10 10 30 20 20 ALBANY 62 51 72 54 76 / 10 10 20 20 20 VALDOSTA 64 51 74 55 76 / 10 10 20 20 20 CROSS CITY 72 52 77 55 78 / 10 10 20 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR THE FOLLOWING ZONES: COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM. && $$ SYNOPSIS/UPDATE...MROCZKA AVIATION...GOREE FIRE WEATHER...CAMP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 225 PM EST SAT DEC 13 2008 ...WARMING TREND IN STORE INTO EARLY NEXT WEEK... .SYNOPSIS... 19Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING MAINLY ZONAL AND QUIET WEATHER ALONG THE NORTHERN GULF COAST. THINGS ARE NOT AS QUIET ELSEWHERE IN THE NATION WITH A SIGNIFICANT SYSTEM DIGGING AND EVOLVING ACROSS THE INTER-MOUNTAIN WEST AND NORTHERN PLAINS. WV IMAGERY SHOWS SHARP TROUGHING IN THE MID/UPPER LEVELS DIGGING ACROSS IDAHO...MONTANA AND WYOMING. THIS IS A RATHER ENERGETIC SYSTEM WITH EVEN A FEW LIGHTNING STRIKES SHOWING UP EARLIER TODAY NEAR NEAR SALT LAKE CITY. SURFACE LOW PRESSURE ASSOCIATED WITH THIS TROUGH WILL EJECT ACROSS WYOMING AND INTO THE NORTHERN PLAINS TONIGHT. VERY LARGE AREA OF THE COUNTRY AHEAD OF AN TO THE NORTH OF THIS FEATURE NOW UNDER WINTER STORM OR BLIZZARD WARNINGS. FURTHER DOWNSTREAM WE FIND A WEAK MID-LEVEL DISTURBANCE EJECTING EASTWARD ACROSS THE SOUTHERN PLAINS. LARGE EXPANSE OF HIGH LEVEL CLOUDS HAS BEEN STREAMING AHEAD OF THIS FEATURE ACROSS OUR SKIES TODAY. AT THE SURFACE...HIGH PRESSURE REMAINS CENTERED TO OUR NORTHEAST OVER THE CAROLINAS WITH RIDGING BACK TO THE SOUTHWEST OVER OUR AREA INTO THE NORTHEAST GULF OF MEXICO. LIGHT EASTERLY FLOW ON THE SOUTHERN PERIPHERY OF THIS RIDGE WILL CONTINUE THROUGH THE OVERNIGHT HOURS AS THE HIGH CENTER NUDGES EASTWARD OFF THE CAROLINA COAST. CURRENT TEMPERATURES THIS AFTERNOON RISING SLOWLY THROUGH THE LOWER AND MIDDLE 50S UNDER THE FILTERED SUNSHINE. .SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... SURFACE HIGH CENTER MOVES EAST OFF THE CAROLINA COAST TONIGHT INTO SUNDAY MORNING. THE COMBINATION OF THIS MOVEMENT AND LOW PRESSURE ARRIVING ACROSS THE CENTRAL U.S. WILL CONTINUE TO SLOWLY VEER OUR LOW LEVEL WINDS TO THE SOUTHEAST. WEAK MID-LEVEL IMPULSE CURRENTLY OVER THE SOUTHERN PLAINS WILL EJECT RAPIDLY EASTWARD TO OUR NORTH THIS EVENING. HOWEVER BEHIND THIS FEATURE WILL SEE A SERIES OF SOUTHERN STREAM IMPULSES RIDING NORTHEAST ALONG THE TEXAS/NORTH-CENTRAL GULF COAST INTO MONDAY. STILL EXPECTING COOL CONDITIONS OVERNIGHT...HOWEVER NOT NEARLY AS COLD AS THIS PAST MORNING. SLOWLY INCREASING MOISTURE ARRIVING ON THE EASTERLY FLOW COMBINED WITH CONTINUED PERIODS OF HIGH LEVEL CIRRUS SHOULD PREVENT EVEN THE COLDEST LOCATIONS FROM APPROACHING THE FREEZING MARK. EVEN LEANING TOWARD THE SLIGHTLY COOLER MAV NUMBERS WILL RESULTS IN LOWS GENERALLY FROM THE MIDDLE 30S TO AROUND 40 INLAND AND MIDDLE 40S ALONG THE IMMEDIATE COAST. LOW LEVEL FLOW BECOMES SOUTHEAST AREA-WIDE FOR SUNDAY WITH A SIGNIFICANT INCREASE IN LOW LEVEL MOISTURE (AT LEAST COMPARED TO TODAY). ONCE AGAIN WITH THE LEADING SOUTHERN STREAM IMPULSE PASSING TO OUR NORTHWEST...WOULD EXPECT PERIODS OF HIGH LEVEL CIRRUS TO CONTINUE TO OVERSPREAD FROM THE WEST AND SOUTHWEST. AS THIS IMPULSE PASSES BY WILL SEE A BROAD AREA OF WEAK SYNOPTIC FORCING SLIDING OVER THE WESTERN ZONES. LOOKING AT A WEST-EAST CROSS-SECTION OF THE AREA...GFS/NAM ARE SHOWING SOME WEAK LIFT BELOW 500MB WITH THE FORCING...HOWEVER THE AIRMASS IS STILL VERY DRY BETWEEN 850MB AND 500MB. MOST GUIDANCE PACKAGES ARE TRYING TO PRODUCE SOME VERY LIGHT QPF ACROSS THE WEST DURING THE DAY SUNDAY...BUT EXPECT EVEN THESE LIGHT AMOUNTS TO BE OVERDONE. BETTER MOISTURE PROFILES (DEEPER MOISTURE) IS FURTHER WEST OVER TOWARD PENSACOLA/MOBILE THROUGH THE AFTERNOON AND WOULD EXPECT ANY MEASURABLE RAINFALL FROM SHOWERS TO BE CONFINED TO THESE AREAS. CAN NOT RULE OUT A FEW RAINDROPS (SPRINKLES) INTO THE EASTERN FL PANHANDLE...HOWEVER IMPACTS WOULD BE VERY LIMITED OR NONE FOR OUTDOOR ACTIVITIES. WARMING TEMPERATURES FOR SUNDAY AFTERNOON WITH NEAR CLIMO READING IN THE LOWER AND MIDDLE 60S NORTH AND UPPER 60S TO AROUND 70 SOUTH. BIT COOLER TEMPS (HOLDING IN THE MIDDLE 60S) CAN BE EXPECTED ALONG THE WAKULLA AND FRANKLIN COUNTY COASTS WITH THE STEADY FLOW OFF THE COOLER SHELF WATERS OF APALACHEE BAY. PLEASANT CONDITIONS FOR MID-DECEMBER ON TAP FOR SUNDAY NIGHT. THE HIGHER LOW LEVEL MOISTURE AND CONTINUED SOUTHEAST FLOW WILL RESULT IN LOW TEMPS ONLY DROPPING TO AROUND 50 FOR THE COLDEST INLAND LOCATIONS AND THE MIDDLE AND UPPER 50S ALONG THE IMMEDIATE COAST. ANOTHER WEAK IMPULSE IS FORECAST TO APPROACH FROM THE WEST AND WEAKEN OVERNIGHT. AGAIN ONLY A CHANCE OF A SPRINKLE OR TWO ROLLING INTO THE EASTERN PANHANDLE OFF THE GULF WITH BETTER CHANCES FOR PASSING SHOWERS REMAINING WEST OF THE FORECAST AREA. MONDAY AND MONDAY NIGHT...VERY PLEASANT TEMPERATURES FOR MID-DEC ANTICIPATED. SURFACE BOUNDARY WILL BE SAGGING SOUTHEAST ACROSS MS/AL THROUGH THE DAY. GFS/NAM BOTH SHOW THIS FRONT STALLING NEAR OR JUST OUTSIDE OF OUR WESTERN AND NORTHERN ZONES MONDAY NIGHT. BY THIS TIME...MOST OF THE MID-LEVEL DRY AIR WILL HAVE BEEN ERODED. THE ADDED LOW LEVEL FOCUS FROM THIS FRONT...COMBINED WITH THE MORE FAVORABLE MOISTURE PROFILES AND SOME WEAK SYNOPTIC FORCING WILL BRING SLIGHT TO LOW END CHANCE POPS (SCT SHOWERS) BACK TO THE FORECAST AREA. HOWEVER...ANY PASSING SHOWERS SHOULD BE GENERALLY OF THE LIGHT VARIETY WITH SMALL ACCUMULATIONS AND LIMITED IMPACTS TO OUTDOOR ACTIVITIES. THE AIRMASS POTENTIAL FOR MONDAY WILL BE QUITE WARM...AND WILL ONLY TAKE A FEW BREAKS OF SUN THROUGH THE DAY TO REACH THE LOWER 70S. LOW TEMPS MONDAY NIGHT MAY FAIL TO DROP BELOW THE MIDDLE 50S FOR EVEN THE COOLEST LOCATIONS. && .LONG TERM (TUESDAY THROUGH SATURDAY)... LARGE SCALE PATTERN IN THE EXTENDED TO BE QUITE DIFFERENT FROM THAT OF THE LAST MONTH. THE MEAN EASTERN TROUGH WILL REDEVELOP OVER THE WESTERN STATES WITH A GENERALLY FLAT RIDGE DEVELOPING ACROSS THE GULF OF MEXICO. TUESDAY WILL SEE A STRONG SFC HIGH OVER THE WESTERN ATLANTIC WITH MOIST LOW LEVEL EAST TO SOUTHEAST FLOW OVER THE CWA. MAY SEE A FEW SHOWERS DEVELOP DURING THIS PERIOD WITH THE MOIST LOW LEVEL FLOW...BUT NOT EXPECTING ANY SIGNIFICANT RAIN AMOUNTS. BY WEDNESDAY...SFC HIGH IS EXPECTED TO WEAKEN AS THE UPPER RIDGE AMPLIFIES A BIT. THIS WILL DRY THINGS OUT FOR THE REMAINDER OF THE FORECAST PERIOD...WITH THE RIDGE KEEPING FRONTAL SYSTEMS STALLED TO THE NORTH. TEMPERATURES WILL RUN ABOVE NORMAL THROUGH THE EXTENDED PERIOD DUE TO THE INFLUENCE OF THE UPPER RIDGE. && .MARINE... FORECAST WATERS REMAIN ON THE SOUTHWEST PERIPHERY OF A SURFACE RIDGE EXTENDING FROM THE CAROLINA COAST TO THE NORTHEAST GULF OF MEXICO. SEEING A SLIGHT DECREASE IN WINDS THIS AFTERNOON...HOWEVER SOLID CAUTIONARY LEVEL EASTERLY FLOW SHOULD RESUME THIS EVENING AS FLOW CONTINUES TO SWING AROUND TO THE EAST. AS IS OFTEN THE CASE WITH EASTERLY FLOW...EXPECTING A SLIGHT NOCTURNAL SURGE IN THE WINDS OVERNIGHT AND WILL LIKELY REACH ADVISORY LEVELS FOR A TIME INTO SUNDAY MORNING. CAUTIONARY LEVEL WINDS AND SEAS ARE EXPECTED TO CONTINUE INTO SUNDAY NIGHT OUT OF THE SOUTHEAST... ESPECIALLY OVER THE WESTERN LEGS. THEREAFTER ANTICIPATING A CONTINUED PERIOD OF SOUTHEASTERLY FLOW INTO EARLY NEXT WEEK WITH WINDS AND SEAS GENERALLY BELOW HEADLINE CRITERIA. && .AVIATION... AS THE LOW LEVEL FLOW GRADUALLY BECOMES MORE EASTERLY AND THEN VEERS MORE TO THE SOUTHEAST TONIGHT AND SUNDAY...LOW LEVEL MOISTURE AND CLOUDS WILL GRADUALLY INCREASE. EXPECT VFR CONDITIONS INTO THE EARLY MORNING HOURS SUNDAY...FOLLOWED BY INCREASING CLOUDS AT AROUND 3 TO 4 THOUSAND FEET SPREADING FROM EAST TO WEST ACROSS THE TRI STATE AREA...WHILE MID AND UPPER LEVEL CLOUDS SPREAD FROM WEST TO EAST AND GRADUALLY THICKEN OVERNIGHT. WINDS OVERNIGHT WILL REMAIN EAST TO SOUTHEAST AT AROUND 5 KNOTS. BY DAYBREAK...AREAS OF FOG AND MVFR CEILINGS ARE EXPECTED TO DEVELOP...MAINLY ACROSS SOUTHEAST ALABAMA...SOUTH CENTRAL GEORGIA AND THE EASTERN FLORIDA BIG BEND. LOOKING AHEAD...A WARMER MOIST SOUTHERLY FLOW WILL ENSURE THE DEVELOPMENT OF MVFR CEILINGS AND VISIBILITIES DURING THE NIGHT AND EARLY MORNING HOURS ACROSS MUCH OF THE AREA INTO THE COMING WEEK. && .FIRE WX... INCREASING CLOUD COVER LIMITED DAYTIME HEATING AND THE RED FLAG WARNING FOR OUR FLORIDA COUNTIES WAS CANCELLED EARLY THIS AFTERNOON. THE LOW LEVEL FLOW WILL CONTINUE TO VEER TO THE EAST AND THEN THE SOUTHEAST...BRINGING INCREASING MOISTURE ACROSS THE TRI STATE AREA DURING THE COMING WEEK...AND RED FLAG CONDITIONS ARE NOT EXPECTED THROUGH THE COMING WEEK. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 41 68 53 73 57 / 05 10 10 20 20 PANAMA CITY 47 68 59 70 61 / 10 10 20 30 20 DOTHAN 40 65 55 69 56 / 10 10 10 30 20 ALBANY 37 65 50 73 55 / 05 10 10 20 20 VALDOSTA 39 68 51 74 56 / 05 10 10 20 20 CROSS CITY 42 72 52 76 55 / 05 10 10 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 11 AM EST SUNDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO 20 NM...COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM...WATERS FROM SUWANNEE RIVER TO APALACHICOLA FL FROM 20 TO 60 NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WEATHER...DUVAL LONG TERM...CAMP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 930 AM EST SAT DEC 13 2008 ...WARMING TREND IN STORE INTO EARLY NEXT WEEK... .SYNOPSIS/UPDATE... 14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING ZONAL AND QUIET WEATHER ALONG THE NORTHERN GULF COAST THIS MORNING. THINGS ARE NOT AS QUIET ELSEWHERE IN THE NATION WITH A SIGNIFICANT SYSTEM DIGGING AND EVOLVING ACROSS THE INTER-MOUNTAIN WEST AND NORTHERN PLAINS. WV IMAGERY SHOWS SHARP TROUGHING IN THE MID/UPPER LEVELS DIGGING ACROSS THE PACIFIC NORTHWEST/IDAHO AND MONTANA. THIS IS A RATHER ENERGETIC SYSTEM WITH EVEN A FEW LIGHTNING STRIKES SHOWING UP NEAR SALT LAKE CITY THIS MORNING. SURFACE LOW PRESSURE ASSOCIATED WITH THIS TROUGH WILL EJECT ACROSS WYOMING AND INTO THE NORTHERN PLAINS TONIGHT. VERY LARGE AREA OF THE COUNTRY AHEAD OF AN TO THE NORTH OF THIS FEATURE NOW UNDER WINTER STORM OR BLIZZARD WARNINGS. FURTHER DOWNSTREAM WE FIND A WEAK MID-LEVEL DISTURBANCE EJECTING OUT OF NEW MEXICO INTO THE SOUTHERN PLAINS. LARGE EXPANSE OF HIGH LEVEL CLOUDS STREAMING AHEAD OF THIS FEATURE WILL INVADE OUR SKIES INTO TONIGHT AND WILL FILTER THE SUNSHINE FOR MOST AREAS BY THIS AFTERNOON. AT THE SURFACE...HIGH PRESSURE CENTERED OVER THE CAROLINAS CONTINUES TO RIDGE BACK OVER OUR AREA. THE CLEAR SKIES AND CALM WINDS UNDER THE RIDGE ALLOWED FOR MANY INLAND SPOTS TO REACH OR DROP A FEW DEGREES BELOW FREEZING AROUND SUNRISE THIS MORNING. CURRENT TEMPERATURES AS OF 9 AM ARE REBOUNDING BACK THROUGH THE 40S ON THEIR WAY TO AFTERNOON HIGHS IN THE MIDDLE AND UPPER 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH. THE FOLLOWING ARE LOW TEMPS FROM A FEW SELECT LOCATIONS ACROSS THE AREA: TALLAHASSEE...28 F VALDOSTA...28 F ALBANY...28 F CROSS CITY...31 F DOTHAN...31 F MARIANNA...31 F PERRY...32 F PANAMA CITY...36 F APALACHICOLA...37 F AS WAS MENTIONED ABOVE...WILL BE LOOKING AT MOSTLY SUNNY BUT FILTERED SKIES THROUGH SOME HIGH LEVEL CIRRUS STREAMING IN FROM THE WEST. SURFACE HIGH PRESSURE CENTERED TO OUR NORTH WILL CONTINUE TO SLIDE EAST REACHING THE CAROLINA COAST THIS EVENING...AND THEN OFF THE COAST SUNDAY MORNING. THE COMBINATION OF THIS HIGH MOVING EAST AND LOW PRESSURE ARRIVING ACROSS THE CENTRAL U.S. WILL SLOWLY TURN OUR WINDS FROM THE NORTHEAST TO THE SOUTHEAST OVER THE NEXT 12 TO 24 HOURS. WHILE STILL LOOKING AT VERY DRY LOW LEVEL CONDITIONS THROUGH THIS AFTERNOON...MOISTURE WILL ONCE AGAIN BEGIN TO INCREASE FOR SUNDAY WITH THE EASTERLY/SOUTHEASTERLY REGIME. WITH A SERIES OF WEAK SOUTHERN STREAM IMPULSES RIDING NORTHEAST ALONG THE TEXAS/NORTH-CENTRAL GULF COAST TONIGHT INTO SUNDAY...WILL CONTINUE TO SEE PERIODS OF MAINLY HIGH LEVEL CIRRUS TO FINISH OFF THE WEEKEND. THIS PAST MORNING REPRESENTS THAT LAST SIGNIFICANT COLD AIR FOR A WHILE WITH A WARMING TREND OVER THE NEXT SEVERAL DAYS BRINGING TEMPS BACK WELL ABOVE NORMAL FOR MID-DECEMBER. LOW TEMPERATURES TONIGHT SHOULD REMAIN ABOVE FREEZING REGION-WIDE WITH UPPER 30S TO AROUND 40 COMMON INLAND AND LOWER TO MIDDLE 40S ALONG THE COAST. SUNDAY AFTERNOON SHOULD SEE TEMPERATURES RIGHT AROUND CLIMO WITH MIDDLE 60S NORTH AND MIDDLE 60S TO AROUND 70 SOUTH. THE TREND ONLY GETS WARMER INTO THE EARLY AND MIDDLE PART OF NEXT WEEK. && .MARINE... FORECAST WATERS REMAIN ON THE SOUTHWEST PERIPHERY OF SURFACE RIDGE EXTENDING FROM THE CAROLINAS TO THE NORTHEAST GULF OF MEXICO. CAUTIONARY LEVEL NORTHEAST FLOW WILL SWING AROUND TO THE EAST BY LATER TODAY AND INTO TONIGHT. AS IS OFTEN THE CASE WITH EASTERLY FLOW...EXPECTING A SLIGHT NOCTURNAL SURGE IN THE WINDS OVERNIGHT AND APPROACHING ADVISORY LEVELS FOR A TIME INTO SUNDAY MORNING. THEREAFTER ANTICIPATING A PROLONGED PERIOD OF SOUTHEASTERLY FLOW INTO TUESDAY OF NEXT WEEK. && .AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH MUCH OF THE FORECAST PERIOD...WITH ONLY A GRADUAL INCREASE IN HIGH CLOUDS FROM WEST TO EAST THROUGH THE DAY TODAY. LOW LEVEL WINDS WILL VEER TO THE EAST THIS MORNING AND THEN GRADUALLY BECOME MORE SOUTHEAST DURING THE AFTERNOON AND EVENING...WITH SPEEDS 5 TO 10 KNOTS. EXPECT WINDS TO REMAIN 3 TO 5 KNOTS EAST TO SOUTHEAST OVERNIGHT. WITH THE INCREASING EASTERLY WIND COMPONENT...LOW LEVEL MOISTURE WILL BEGIN TO SPREAD BACK ACROSS THE TRI STATE AREA...AND THIS WILL RESULT IN AN INCREASE IN LOWER CLOUDS OVERNIGHT...MAINLY BETWEEN 3 AND 4 THOUSAND FEET... THOUGH PATCHES OF MVFR CEILINGS ARE POSSIBLE BY AROUND DAYBREAK ON SUNDAY. && .FIRE WX... THE DRY AIR MASS WILL REMAIN IN PLACE FOR TODAY LEADING TO RED FLAG CONDITIONS OVER FLORIDA THIS AFTERNOON. WILL CONTINUE THE RED FLAG WARNING. THEREAFTER...INCREASING MOIST EAST TO SOUTHEASTERLY FLOW WILL KEEP RH VALUES ABOVE CRITICAL LEVELS FOR THE NEXT SEVERAL DAYS. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 59 40 67 53 72/ 0 0 10 10 20 PANAMA CITY 60 46 69 57 73/ 0 0 10 10 20 DOTHAN 55 40 65 52 71/ 0 0 10 10 20 ALBANY 57 37 64 51 72/ 0 0 10 10 20 VALDOSTA 58 39 67 52 73/ 0 0 10 10 20 CROSS CITY 62 42 74 54 75/ 0 0 10 10 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING FROM 1 PM EST /12 PM CST/ UNTIL 6 PM EST /5 PM CST/ THIS AFTERNOON FOR ALL ZONES. GM...NONE. && $$ SYNOPSIS/UPDATE...MROCZKA AVIATION...DUVAL FIRE WEATHER...CAMP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 916 AM MST SAT DEC 13 2008 .UPDATE...CENTER OF VERY DEEP COMPLEX LOW NEAR NORTHWESTERN CORNER OF FCST AREA THIS MORNING PER WV SAT IMAGERY. IR SHOWS DRAMATIC DRY SLOW WORKING SOUTHEAST ACROSS FCST AREA THROUGH CENTRAL MTNS ANT INTO THE EDGES OF THE SNAKE VALLEY. INSTABILITY CLOUDS/SHOWERS WORKING INTO CENTRAL MTNS BEHIND THE DRY SLOT. MEANWHILE...DEEPER MOISTURE OVER EASTERN EDGES OF FCST AREA KEEPING SNOW IN PLACE ALONG EASTERN HIGHLANDS. WINDS CONTINUE TO BE A PROBLEM. SFC OBS SHOW WIDESPREAD WINDY CONDITIONS WITH A FEW LOCATIONS GUSTING OVER 40 MPH PER MESOWEST DATA. THE SNOW THAT HAD FALLEN EARLIER PRODUCING SOME BLOWING AND DRIFTING PER AREA WEBCAMS. GIVEN COMPLEX SCENARIO HAVE MADE THE FOLLOWING HEADLINE/GRID UPDATES. HAVE DROPPED THE WARNING FOR THE CENTRAL MOUNTAIN ZONES AND LOWERED POPS SLIGHTLY. SHOULD SEE MAINLY CONVECTIVE SHOWERS THERE TODAY WITH WINDS STICKING TO THE HIGHER ELEVATIONS. FOR THE SNAKE VALLEY...HAVE CHANGED WINTER WX ADVISORY TO SIMPLY A WIND ADVISORY. WILL MENTION BLOWING/DRIFTING ALONG INTERSTATE 15 WHERE MOST OF THE SNOW APPEARED TO HAVE FALLEN OVERNIGHT. HAVE LEFT REST OF THE MOUNTAIN ZONES IN WINTER STORM WARNINGS. THE EASTERN HIGHLANDS CONTINUE TO SEE BOTH SNOW AND WIND TODAY...BUT THE ONLY STICKLER IS ZONE 22. SNOW HAS STOPPED AND THEY WILL BE DRY SLOTTED BUT THE STRONGER WINDS THERE WILL KEEP BLOWING SNOW A HAZARD PARTICULARLY FOR INTERSTATE 84. TEXT PRODUCT UPDATES FORTHCOMING. DMH && .PREV DISCUSSION... /ISSUED 342 AM MST SAT DEC 13 2008/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. STRONG COLD FRONT HAS ENTERED IDAHO AND IS QUICKLY MOVING THROUGH OUR REGION. WEBCAMS AROUND THE AREA SHOW SNOW OVER MUCH OF THE WESTERN PORTIONS OF OUR FORECAST AREA. AS SUCH...WINTER STORM WARNINGS CONTINUE FOR CENTRAL MTNS THROUGH 5PM THIS EVENING AND ERN AND SRN HIGHLANDS CONTINUE THROUGH 5AM TOMORROW MORNING. IN ADDITION...WINTER WX ADVISORY WILL CONTINUE FOR SNAKE RIVER PLAIN THROUGH 11PM TONIGHT. LATEST WSR-88D IMAGERY SHOWING LARGE SWATH OF MOISTURE MOVING FROM SW TO NE OVER BURLEY UP TO IDAHO FALLS PRODUCING SOME HEAVIER SNOW AND RAIN SHOWERS. LATEST RUC/GFS/NAM-12 MODELS HIGHLIGHTING CHANGE IN AREAL COVERAGE OF PRECIP AS MOST OF MOISTURE PROGGED TO AFFECT ERN AND SRN HIGHLANDS WITH LESS SNOW AMTS OVER CENTRAL MTNS. UPPER LEVEL LOW IS STILL OVER OR/WA BORDER...HOWEVER...AND WILL PRODUCE MORE SNOW FOR THE MTNS AS IT APPROACHES AND MOVES OFF TO THE E. SNOW AMTS STILL LOOK REASONABLE WITH 6 TO 12" OVER ALL MTN REGIONS AND 2 TO 4" ACROSS SNAKE RIVER PLAIN. STRONG WINDS WILL USHER IN THE COLD FRONT THIS MORNING WITH GUSTS OF 35 MPH AND ABOVE...MAX WINDS ARE EXPECTED WITH FRONTAL PASSAGE. TEMPERATURES WILL TAKE A NOSEDIVE ONCE FRONT MOVES THROUGH AS SEVERAL SITES INDICATED 10 DEGREE DROP IN TEMPERATURE OVER 1 HR PERIOD AFTER FROTNAL PASSAGE...A STRONG FRONT TO SAY THE LEAST. ONCE FRONT MOVES THROUGH AREA THIS AFTERNOON...ALL MODELS SHOWING WEAK DISTURBANCES MOVING THROUGH LONGWAVE PATTERN WITH SOME MODEST ASSOCIATED AREAS OF PRECIP. ADDITIONAL ACCUMULATIONS VERY LIKELY UNDER THESE QUICK MOVING DISTURBANCES. RENWICK LONG TERM...MONDAY THROUGH SATURDAY. BOTH THE GFS AND ECM SHOW GOOD AGREEMENT WITH CLOSED LOW DROPPING SOUTH ALONG THE OREGON COAST AND A WARM FRONTAL BOUNDARY MOVING NORTHWARD INTO FORECAST AREA. FORECAST FOLLOWS TIMING OF THESE MODELS. NAM TIMING IS MUCH SLOWER. CONFIDENCE RUNNING HIGHER AND POPS WERE PUSHED A BIT HIGHER...PARTICULARLY FOR THE EASTERN HIGHLANDS. THE NEXT ARCTIC DISTURBANCE DROPS OVER THE RIDGE AND SOUTHWARD INTO IDAHO BY THURSDAY. THE 13/00Z ECMWF MODEL RUN IS MUCH MORE CONSISTENT WITH THE GFS DROPPING THIS DISTURBANCE THROUGH SOUTHEAST IDAHO THURSDAY NIGHT THROUGH SATURDAY MORNING. CONFIDENCE IS INCREASING AND POPS WERE RAISED SOME HERE AS WELL. GFS 700 MB WINDS AND TEMPERATURES BRING FAIRLY COLD AIR DOWN INTO IDAHO TOO. DETAILS OF COLD BOX CAR AIR MASS MAKING IT INTO SOUTHEAST IDAHO STILL A LITTLE FUZZY. HAVE NUDGED FORECAST TEMPERATURES DOWN A FEW DEGREES IN CONSERVATIVE FASHION. RS AVIATION...AT 13/10Z SURFACE COLD FRONT IS JUST WEST OF KBYI WITH A FEW GUSTS TO THE MID 40 MPH RANGE NOTED ON MESONET SITES. FRONT EXPECTED TO REACH KPIH BETWEEN 1100-1130Z. LATEST RUC UPDATE ENDS SNOW AT KIDA AND KPIH AFTER 15Z...ABOUT 3 HOURS QUICKER THAN PREVIOUSLY ANTICIPATED. SOUTHWEST WINDS 20 TO 30 MPH WILL PERSIST THROUGH AT LEAST 21Z...BY THAT TIME THE SURFACE PRESSURE GRADIENT DECREASES PER THE NAM12. WINDS COULD HANG IN THERE A BIT LONGER AS THE SURFACE LOW HAS NOT MOVED EAST OF WYOMING JUST YET. PERSISTENT MVFR CEILINGS CONTINUE OVER NIGHT IN AN UNSETTLED PATTERN. NEXT DISTURBANCE SHOULD PUSH SHOWERS THROUGH THE FORECAST AREA SUNDAY AFTERNOON. RS && .PIH WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 8 PM MST THIS EVENING FOR IDZ017-020-021. WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR IDZ019-023- 025. WINTER STORM WARNING UNTIL 8 PM MST THIS EVENING FOR IDZ022-024. && $$ id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 342 AM MST SAT DEC 13 2008 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT. STRONG COLD FRONT HAS ENTERED IDAHO AND IS QUICKLY MOVING THROUGH OUR REGION. WEBCAMS AROUND THE AREA SHOW SNOW OVER MUCH OF THE WESTERN PORTIONS OF OUR FORECAST AREA. AS SUCH...WINTER STORM WARNINGS CONTINUE FOR CENTRAL MTNS THROUGH 5PM THIS EVENING AND ERN AND SRN HIGHLANDS CONTINUE THROUGH 5AM TOMORROW MORNING. IN ADDITION...WINTER WX ADVISORY WILL CONTINUE FOR SNAKE RIVER PLAIN THROUGH 11PM TONIGHT. LATEST WSR-88D IMAGERY SHOWING LARGE SWATH OF MOISTURE MOVING FROM SW TO NE OVER BURLEY UP TO IDAHO FALLS PRODUCING SOME HEAVIER SNOW AND RAIN SHOWERS. LATEST RUC/GFS/NAM-12 MODELS HIGHLIGHTING CHANGE IN AREAL COVERAGE OF PRECIP AS MOST OF MOISTURE PROGGED TO AFFECT ERN AND SRN HIGHLANDS WITH LESS SNOW AMTS OVER CENTRAL MTNS. UPPER LEVEL LOW IS STILL OVER OR/WA BORDER...HOWEVER...AND WILL PRODUCE MORE SNOW FOR THE MTNS AS IT APPROACHES AND MOVES OFF TO THE E. SNOW AMTS STILL LOOK REASONABLE WITH 6 TO 12" OVER ALL MTN REGIONS AND 2 TO 4" ACROSS SNAKE RIVER PLAIN. STRONG WINDS WILL USHER IN THE COLD FRONT THIS MORNING WITH GUSTS OF 35 MPH AND ABOVE...MAX WINDS ARE EXPECTED WITH FRONTAL PASSAGE. TEMPERATURES WILL TAKE A NOSEDIVE ONCE FRONT MOVES THROUGH AS SEVERAL SITES INDICATED 10 DEGREE DROP IN TEMPERATURE OVER 1 HR PERIOD AFTER FROTNAL PASSAGE...A STRONG FRONT TO SAY THE LEAST. ONCE FRONT MOVES THROUGH AREA THIS AFTERNOON...ALL MODELS SHOWING WEAK DISTURBANCES MOVING THROUGH LONGWAVE PATTERN WITH SOME MODEST ASSOCIATED AREAS OF PRECIP. ADDITIONAL ACCUMULATIONS VERY LIKELY UNDER THESE QUICK MOVING DISTURBANCES. RENWICK .LONG TERM...MONDAY THROUGH SATURDAY. BOTH THE GFS AND ECM SHOW GOOD AGREEMENT WITH CLOSED LOW DROPPING SOUTH ALONG THE OREGON COAST AND A WARM FRONTAL BOUNDARY MOVING NORTHWARD INTO FORECAST AREA. FORECAST FOLLOWS TIMING OF THESE MODELS. NAM TIMING IS MUCH SLOWER. CONFIDENCE RUNNING HIGHER AND POPS WERE PUSHED A BIT HIGHER...PARTICULARLY FOR THE EASTERN HIGHLANDS. THE NEXT ARCTIC DISTURBANCE DROPS OVER THE RIDGE AND SOUTHWARD INTO IDAHO BY THURSDAY. THE 13/00Z ECMWF MODEL RUN IS MUCH MORE CONSISTENT WITH THE GFS DROPPING THIS DISTURBANCE THROUGH SOUTHEAST IDAHO THURSDAY NIGHT THROUGH SATURDAY MORNING. CONFIDENCE IS INCREASING AND POPS WERE RAISED SOME HERE AS WELL. GFS 700 MB WINDS AND TEMPERATURES BRING FAIRLY COLD AIR DOWN INTO IDAHO TOO. DETAILS OF COLD BOX CAR AIR MASS MAKING IT INTO SOUTHEAST IDAHO STILL A LITTLE FUZZY. HAVE NUDGED FORECAST TEMPERATURES DOWN A FEW DEGREES IN CONSERVATIVE FASHION. RS && .AVIATION...AT 13/10Z SURFACE COLD FRONT IS JUST WEST OF KBYI WITH A FEW GUSTS TO THE MID 40 MPH RANGE NOTED ON MESONET SITES. FRONT EXPECTED TO REACH KPIH BETWEEN 1100-1130Z. LATEST RUC UPDATE ENDS SNOW AT KIDA AND KPIH AFTER 15Z...ABOUT 3 HOURS QUICKER THAN PREVIOUSLY ANTICIPATED. SOUTHWEST WINDS 20 TO 30 MPH WILL PERSIST THROUGH AT LEAST 21Z...BY THAT TIME THE SURFACE PRESSURE GRADIENT DECREASES PER THE NAM12. WINDS COULD HANG IN THERE A BIT LONGER AS THE SURFACE LOW HAS NOT MOVED EAST OF WYOMING JUST YET. PERSISTENT MVFR CEILINGS CONTINUE OVER NIGHT IN AN UNSETTLED PATTERN. NEXT DISTURBANCE SHOULD PUSH SHOWERS THROUGH THE FORECAST AREA SUNDAY AFTERNOON. RS && .PIH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR IDZ017- 020-021. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR IDZ019-023-025. WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR IDZ022-024. WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR IDZ018- 031-032. && $$ id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 205 PM CST SUN DEC 14 2008 .DISCUSSION... ISSUED 130 PM CST SUN DEC 14 2008 ARCTIC COLD FRONT RACING EWD ACRS EAST CNTRL IOWA EARLY THIS AFTN AND THAT WILL BE OUR WX MAKER...AT LEAST IN THE SHORT TERM...WITH PRECIP CHANCES...TYPES AND AMOUNTS TNT THE MAIN CONCERN. TEMPERATURES DROP OFF RAPIDLY BEHIND THE FRONT AND EXPECT TEMPERATURES ON MONDAY TO BE SOME 25 TO 35 DEGREES COLDER THAN TODAY. ALREADY SEEING AN INCREASE IN RADAR RETURNS IMMEDIATELY BEHIND THE STRONG COLD FRONT IN NRN MO AND ERN IOWA...INDICATIVE OF AN INCREASING TREND IN 700-500 MB FRONTOGENETICAL FORCING. THIS TREND WL CONTINUE INTO THE OVERNIGHT HOURS AS THE FRONT PUSHES TO OUR EAST AFTR MIDNIGHT. CONCERN ON MONDAY WL BE JUST HOW QUICKLY THE PRECIP ENDS...ESP IN THE SOUTHEAST WHERE THE BNDRY IS EXPECTED TO SLOW DOWN SOME. NEXT FORECAST CHALLENGE WL BE WITH SNOW AND OR FREEZING RAIN AMTS WITH TUESDAYS SYSTEM...WITH ANOTHER SOUTHWEST WAVE PUSHING IN LATER ON THURSDAY BRINGING ADDL PRECIP TO THE FORECAST AREA FOR THE END OF THE WEEK. SHORT TERM...TONIGHT THROUGH WEDNESDAY HAVE USED A BLEND OF THE NAM AND LOCAL ARW MODEL WITH THE TIMING OF THE COLD FRONT ACRS THE FORECAST AREA THIS EVENING. SO FAR...THE ARW MODEL HAS BEEN THE QUICKEST AND HAS BEEN VERIFYING THRU EARLY THIS AFTN. WITH THE INCRG FRONTOGENETICAL FORCING IMMEDIATELY BEHIND THE ARCTIC BNDRY...EXPECT THE PRECIP COVERAGE TO INCREASE AS WELL AS THE SYSTEM TRANSLATES EAST THIS EVENING. FORECAST SOUNDINGS SHOWING SOME DECENT LAPSE RATES AS WELL...ESP ACRS THE SOUTHEAST LATER THIS EVENING WITH HI RES MODELS SUGGESTING SOME BANDING OF THE PRECIP PSBL EARLY THIS EVENING. COULD SEE SOME ISOLD THUNDER WITH THE INITIAL BAND OF RAIN JUST AHEAD OF THE ARCTIC FRONT...ESP ACRS THE SOUTHEAST THIS EVENING. THE MAIN FORECAST CONCERN BECOMES HOW QUICKLY THE COLD AIR GETS INTO THE AREA. BASED ON TIMING OF THE CURRENT POSITION (18Z) OF THE FRONT...WE SHOULD SEE TEMPS START TO DROP OFF RAPIDLY IN THE WEST ARND 00Z AND NEAR THE I-55 CORRIDOR ARND 03Z WITH COUNTIES ACRS THE SOUTHEAST SEEING THE BNDRY ENTER THEIR AREA JUST AFTR 06Z. NAM BUFKIT SOUNDINGS CONTINUE TO SUGGEST A BRIEF PERIOD WHERE THE RAIN GOES OVER TO FREEZING RAIN...AND THEN TO SLEET AND SNOW BEFORE THE MOISTURE DEPARTS AT THE MID AND UPPER LEVELS LATE THIS EVENING INTO THE OVERNIGHT HOURS. LOOKING FOR AROUND A TENTH OF AN INCH OF ICE WITH AN INCH OR LESS OF SNOW WITH THIS FAST MOVING FRONTAL BOUNDARY. TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE SINGLE DIGITS NW TO THE UPPER 20S FAR SE BY DAWN MONDAY WITH NEAR OR SUBZERO WIND CHILLS WEST OF I-55. QUITE A CHANGE IN 24 HOURS! BASED ON THE EXPECTED FREEZING RAIN...SLEET AND LIGHT SNOW TONIGHT INTO THE MONDAY MRNG RUSH HOUR...HAVE GONE WITH A WINTER WEATHER ADVSY FOR LIGHT ICING THAT WILL EXTEND INTO MONDAY MRNG. MUCH COLDER WEATHER TO FOLLOW FOR MONDAY WITH TEMPERATURES HAVING A TOUGH TIME GETTING OUT OF THE TEENS IN THE NW. HAVE TRENDED TWDS THE COLDER MET GUIDANCE FOR TOMORROW. MODELS INSIST THE PRECIP SHIELD SHOULD PUSH SOUTH AND EAST OF OUR AREA TMRW AFTN BUT IT WL BE CLOSE FOR OUR I-70 COUNTIES. HOWEVER...BASED ON WHAT IS HAPPENING WITH THE FRONTAL MOVMENT THIS AFTN OUT TO OUR WEST...FEEL THE ARW SOLUTION LOOKS A BIT BETTER THAN THE NAM. THE NAM DOES BRING ANOTHER WAVE OF FREEZING RAIN AND SNOW INTO SE IL BY LATE TMRW AFTN AND EVE. FOR NOW WL KEEP THE PRECIP JUST TO OUR SOUTH MONDAY AFTN AND EVENING. NEXT WAVE WL TRACK INTO THE SRN PLAINS EARLY ON TUESDAY AND BEGIN TO SWING NE INTO THE MIDWEST. IMPRESSIVE ISENT LIFT NOTED ON THE 295K SFC WITH MIXING RATIOS OF 4 TO 6 G/KG UPSTREAM FROM OUR AREA. HOWEVER...IT APPEARS THE SYSTEM SPEED WL HELP TO CUT BACK ON THE SNOW AMTS ACRS OUR NORTH AND NW...WHILE WARMER THERMAL PROFILES TO THE SOUTH SUGGEST MORE OF A MIX OF SNOW...SLEET AND FREEZING RAIN ON TUESDAY BEFORE THE SYSTEM PULLS OUT TUE EVENING. SNOWFALL AMTS OF 3 TO 5 INCHES LOOK REASONABLE AT THIS POINT...MAINLY NORTH OF A RUSHVILLE TO PEORIA TO LACON LINE. MODEL SOUNDINGS HAVE BEEN TRENDING A BIT WARMER OVR THE PAST FEW RUNS...ESP ACRS THE CNTRL AND SOUTHERN AREAS...THEREFORE HAVE ADJUSTED MORE TWDS A MIX RATHER THAN STRAIGHT SNOW IN THOSE AREAS. LONG TERM...THURSDAY THROUGH SUNDAY ACTIVE WX PATTERN TO CONTINUE ACRS THE FORECAST AREA WITH SOUTHWESTERLY FLOW PREVAILING THRU THE PERIOD. NEXT SOUTHWEST WAVE WL AFFECT OUR AREA THU AND FRIDAY WITH A MIXED BAG OF PRECIP AT THE ONSET...WITH MODELS TRENDING WARMER WITH THE SFC LOW FCST TO TRACK RIGHT ACRS THE FORECAST AREA. THE LATEST ECMWF INDICATING +10 850 TEMPS ACRS OUR SOUTH BY THU AFTN AND EVENING. DEPENDING ON HOW QUICKLY THE ARCTIC AIR MOVES OUT OF THE AREA LATER THIS WEEK WL DETERMINE WHETHER OR NOT WE SEE SIGNIFICANT ICING OR JUST RAIN WITH THIS SYSTEM. FOR NOW...WL INCLUDE FREEZING RAIN DURING THE MORNING...AND THEN GRDLY TRANSITION TO RAIN FROM SOUTH TO NORTH DURING THE DAY BASED ON THE LATEST ECMWF SFC LOW TRACK. AFTER THE THU AND FRI SYSTEM...ENSEMBLES ARE ALL OVER THE PLACE WITH RESPECT TO THE TIMING OF NEXT SHORTWAVE PRECIP NEXT WEEKEND WHICH WILL BE FOLLOWED BY ANOTHER SURGE OF ARCTIC AIR WITH GUID INDICATING -15 TO -20 DEG C AT 850 MB LATE SUNDAY INTO SUNDAY NIGHT. SMITH && .AVIATION... ISSUED 1135 AM CST SUN DEC 14 2008 TIMING OF STRONG COLD FRONT AND ASSOCIATED WIND/WEATHER IS THE MAIN ISSUE WITH THE 18Z TAFS. FRONT HAS PICKED UP SPEED THIS MORNING AND WAS ALREADY MOVING INTO EASTERN IOWA AND NORTH CENTRAL MISSOURI. AWIPS TIME-OF- ARRIVAL TOOL HAS IT REACHING KPIA AROUND 00Z...KSPI/KBMI AROUND 02Z...KDEC 04Z AND KCMI 05Z. THIS MATCHES UP WELL WITH THE RUC AND ARW-20 MODELS. PRECIPITATION AHEAD OF THIS FRONT WILL START OUT AS SOME DRIZZLE...THEN PICK UP IN INTENSITY WITH CEILINGS LOWERING SLIGHTLY. RAPID TEMPERATURE FALLS BEHIND THE FRONT WILL RESULT IN PRECIPITATION TRANSITIONING OVER TO FREEZING RAIN AND SLEET FOR 2-3 HOURS...BEFORE CHANGING TO SNOW. WESTERN TERMINALS OF KSPI/KPIA SHOULD SEE THE SNOW LARGELY TAPER OFF BY SUNRISE. KEPT MENTION OF WIND SHEAR AT THE BEGINNING OF THE TAF PERIOD. PIREP FROM KMLI AND AIRCRAFT SOUNDING FROM KBMI STILL INDICATE WINDS OF 60-70 KNOTS ONLY ABOUT 2000 FEET OFF THE SURFACE. THE FULL EFFECTS OF THIS HAVENT BEEN ABLE TO MIX DOWN WITH THE INVERSION STILL IN PLACE...BUT SURFACE GUSTS IN THE 30-35 KNOT RANGE ARE STILL EXPECTED TO CONTINUE. WINDS TO REMAIN RATHER GUSTY OVERNIGHT AND MONDAY MORNING BEHIND THE FRONT...BUT SHOULD GRADUALLY DIMINISH. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST MONDAY FOR ILZ062-063-066>068-071>073. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ILZ038-042>046- 051>057-061>063-066>068-071>073. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR ILZ027>031-036-037-040-041-047>050. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST MONDAY FOR ILZ038-042>046-051>057-061. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1138 AM CST SUN DEC 14 2008 .DISCUSSION... ISSUED 1104 AM CST SUN DEC 14 2008 SIGNIFICANT CHANGES MADE TO THE GOING FORECAST FOR TONIGHT INTO MONDAY. VISIBLE SATELLITE IMAGES AND SURFACE OBSERVATIONS SHOW THE STRONG COLD FRONT MOVING FASTER THAN INITIALLY EXPECTED...HAVING ALREADY PASSED DES MOINES AND KANSAS CITY BY 10 AM. FRONT SHOULD BE BEGINNING TO MOVE INTO THE WESTERN CWA TOWARD SUNSET...REACHING I-55 AROUND 00Z AND THE FAR SOUTHEAST CWA AROUND 08Z. UPSTREAM OBS SHOWING CURRENT TEMPERATURES BEHIND THE FRONT IN THE SINGLE DIGITS AND TEENS...WITH VERY LOW DEWPOINTS AS WELL. LOW TEMPERATURES WERE ADJUSTED DOWNWARD TONIGHT TO ACCOUNT FOR THIS...WITH SOME TWEAKING OF THE MONDAY TEMPERATURE GRIDS TO MORE ACCURATELY REFLECT THE HOULRY TRENDS. LATEST NAM-12 MODEL SHOWING PRECIPITATION EXPECTED TO BE MOST WIDESPREAD OVER THE CWA THIS EVENING...TAPERING OFF OVERNIGHT WEST OF I-55. MODEL SOUNDINGS STILL SHOWING A TRANSITION TO FREEZING RAIN...SLEET AND SNOW...WITH ONLY A COUPLE HOURS BETWEEN THE LIQUID RAIN AND THE SNOW. AIR TEMPERATURES IN THE UPPER 40S AND LOWER 50S TODAY SHOULD KEEP THE GROUND LARGELY WARM ENOUGH FROM ANY SIGNIFICANT ICING TONIGHT...ALTHOUGH THE RAIN ON THE GROUND FROM EARLIER WILL QUICKLY FREEZE AS TEMPERATURES HAVE BEEN PLUNGING 20-30 DEGREES WITH THE INITIAL FRONTAL PASSAGE. && .AVIATION... ISSUED 1135 AM CST SUN DEC 14 2008 TIMING OF STRONG COLD FRONT AND ASSOCIATED WIND/WEATHER IS THE MAIN ISSUE WITH THE 18Z TAFS. FRONT HAS PICKED UP SPEED THIS MORNING AND WAS ALREADY MOVING INTO EASTERN IOWA AND NORTH CENTRAL MISSOURI. AWIPS TIME-OF- ARRIVAL TOOL HAS IT REACHING KPIA AROUND 00Z...KSPI/KBMI AROUND 02Z...KDEC 04Z AND KCMI 05Z. THIS MATCHES UP WELL WITH THE RUC AND ARW-20 MODELS. PRECIPITATION AHEAD OF THIS FRONT WILL START OUT AS SOME DRIZZLE...THEN PICK UP IN INTENSITY WITH CEILINGS LOWERING SLIGHTLY. RAPID TEMPERATURE FALLS BEHIND THE FRONT WILL RESULT IN PRECIPITATION TRANSITIONING OVER TO FREEZING RAIN AND SLEET FOR 2-3 HOURS...BEFORE CHANGING TO SNOW. WESTERN TERMINALS OF KSPI/KPIA SHOULD SEE THE SNOW LARGELY TAPER OFF BY SUNRISE. KEPT MENTION OF WIND SHEAR AT THE BEGINNING OF THE TAF PERIOD. PIREP FROM KMLI AND AIRCRAFT SOUNDING FROM KBMI STILL INDICATE WINDS OF 60-70 KNOTS ONLY ABOUT 2000 FEET OFF THE SURFACE. THE FULL EFFECTS OF THIS HAVENT BEEN ABLE TO MIX DOWN WITH THE INVERSION STILL IN PLACE...BUT SURFACE GUSTS IN THE 30-35 KNOT RANGE ARE STILL EXPECTED TO CONTINUE. WINDS TO REMAIN RATHER GUSTY OVERNIGHT AND MONDAY MORNING BEHIND THE FRONT...BUT SHOULD GRADUALLY DIMINISH. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ILZ038-042>046- 051>057-061>063-066>068-071>073. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 831 PM EST SUN DEC 14 2008 .UPDATE... MAIN CONCERN ATTM IS PERIOD OF HEAVY FREEZING RAIN WHICH OCCURRED BEHIND THE CDFNT OVER ERN IA/NW IL THIS EVE. FORCING FOR POST FRONTAL PRECIP APPEARS TO BE A WK SHRTWV OVER NE FROM NEB/WRN IA WHICH IS EXPECTED TO LIFT NE INTO WI OVERNIGHT PROVIDING LESS POST FRONTAL PRECIP IN OUR AREA. THIS SCENARIO SUPPORTED BY 18Z NAM AND 21Z RUC WHICH BOTH SUGGEST THAT THIS HEAVY POST FRONTAL PRECIP WILL NOT TRANSLATE EWD INTO OUR CWA. STILL GIVEN ONGOING ZR OCCURRING BEHIND FRONT...FELT IT WAS WORTH ADDING A MENTION IN THE ZFP/GRIDS FOR WRN AREAS LATE TONIGHT. OTHER CONCERN IS WINDS WHICH HAVE BEEN BLO ADVISORY CRITERIA TODAY AND TONIGHT SO FAR. TEMPS HAVE BEEN CREEPING UP ALLOWING FOR A LITTLE BETTER MIXING OVERNIGHT THAN OCCURRED TODAY. FROPA SHOULD ALSO ENHANCE THE MIXING AND WITH WOLCOTT PROFILER SHOWING 65KT IN LOWEST GATE AT 01Z AM RELUCTANT TO DROP ADVISORY AND RATHER OPTED TO CONT IT. MINOR ADJUSTMENTS MADE TO TEMPS FOR CONTD SLOW RISING TREND UNTIL FROPA WHEN IN A PD OF 3-6HRS TEMPS SHOULD CRASH FROM U40S/L50S TO M-U20S. && .PREV DISCUSSION... /ISSUED 643 PM EST SUN DEC 14 2008/ AVIATION... LITTLE CHANGE MADE TO PREVIOUS TAFS. A STRONG CDFNT WAS MOVING INTO WRN IL THIS EVE. VERY STRONG SOUTHERLY FLOW AHEAD OF THIS FRONT WILL RESULT IN SFC GUSTS TO 35KT AT TIMES OVERNIGHT WITH POTENTIAL FOR LLWS. AN AREA OF RAIN HAS DEVELOPED ALONG/AHEAD OF THE FRONT AND SHOULD MOVE INTO THE TERMINALS LATE TONIGHT...WITH OCNL LIGHT RAIN OR DRIZZLE IN ADVANCE OF THAT. CDFNT EXPECTED TO MOVE THROUGH SBN AROUND 09Z AND FWA 12Z. SOME FREEZING RAIN AND SLEET BEING REPORTED BEHIND THE FRONT OVER ERN IA ATTM. MODELS INDICATING LOW LEVEL DRYING BEHIND FRONT MAY BE SUFFICIENT TO PREVENT ZR BY THE TIME THE FRONT GETS INTO NRN INDIANA...JUST CONTINUED WITH MENTION OF A PD OF POST FRONTAL SLEET AND SNOW ATTM. LITTLE SNOW ACCUM EXPECTED AS DRIER AIR MOVES IN RAPIDLY AND DID IMPROVE VSBYS A LITTLE QUICKER BEHIND THE FRONT THAN PREVIOUS ISSUANCE...THOUGH MVFR STRATO CU DECK WILL LIKELY LINGER THROUGH THE DAY AS MOISTURE SHOULD BE TRAPPED BENEATH SUBSIDENCE INVERSION IN SHALLOW ARCTIC AIRMASS. PREV DISCUSSION... /ISSUED 335 PM EST SUN DEC 14 2008/ SHORT TERM... TONIGHT THROUGH MONDAY NIGHT. STRONG COLD FRONT...NOW EXTENDING FROM EASTERN IOWA INTO NORTH CENTRAL OKLAHOMA...WILL CONTINUE TO MOVE EASTWARD TONIGHT AND SHOULD REACH OUR WESTERN ZONES LATE TONIGHT AND INTO EARLY MONDAY MORNING. PRECIPITATION HAS BEEN DECREASING ACROSS THE AREA THROUGH THIS AFTERNOON...BUT RE- DEVELOPMENT IS EXPECTED ALONG AND EAST OF THE FRONT. NOT MUCH IN THE WAY OF CHANGE EXPECTED FROM THE PREVIOUS FORECAST PACKAGE EXCEPT THAT GUIDANCE SUGGESTS LOW TEMPERATURES TOMORROW NIGHT SHOULD BE AT LEAST A CATEGORY LOWER THAN EARLIER ANTICIPATED. PRECIPITATION TIMING AND TYPE WILL BE THE BIGGEST PROBLEM WITH THIS FORECAST. UPSTREAM OBSERVATIONS INDICATE THAT THERE HAS BEEN A TRANSITION ZONE ASSOCIATED WITH THE FRONT. RAIN HAS BRIEFLY CHANGED TO FREEZING RAIN OR SLEET BEFORE CHANGING OVER TO SNOW. THIS TREND SHOULD CONTINUE AS THE BOUNDARY SWEEPS ACROSS THE AREA. THEREFORE... WE SHOULD SEE AN HOUR OR TWO WINDOW WHERE THERE IS SOME FREEZING RAIN OR SLEET EARLY MONDAY MORNING BEFORE CHANGING TO SNOW. AT THIS TIME...IT DOES NOT APPEAR THERE WILL BE SIGNIFICANT ICE ACCUMULATION .SO NO ADVISORY IS NEEDED. HOWEVER...WILL NEED TO MONITOR FOR LATER TRENDS. WINDS WILL CONTINUE TO BE A PROBLEM. WINDS HAVE CALMED DOWN A LITTLE BIT THIS AFTERNOON...BUT SHOULD STRENGTHEN BACK UP AS THE FRONT APPROACHES. WILL LIKELY SEE ADVISORY LEVEL GUSTS. ALSO...THERE COULD BE A TIME OF BLOWING SNOW BEHIND THE FRONT BEFORE THE GRADIENT RELAXES BY TOMORROW AFTERNOON. LONG TERM... TUESDAY THROUGH SUNDAY. .WINTRY MIX LATE TUESDAY INTO TUESDAY NIGHT... AT THIS POINT NOT A LOT OF CHANGES TO LONG TERM GRIDS WITH ACTIVE PATTERN TO CONTINUE THROUGH THE PERIOD. THE MAIN FOCUS WILL BE ON THE FIRST 24 TO 36 HOURS OF THE LONG TERM. FAST MOVING WAVE WILL MOVE ARRIVE INTO THE AREA BY AFTERNOON WITH PRECIP LIKELY RAPIDLY INCREASING TOWARDS EVENING. INCREASED POPS SOMEWHAT AND EXPANDED TO COVER THIS TREND. HAVE LEFT MIX BAG IN PLACE FOR TUESDAY NIGHT INTO EARLY WEDS. MODELS ALL SHOW A TONGUE OF WARM AIR ALOFT MOVING IN TO AT LEAST SOME OF THE CWA...ESPECIALLY SE QUARTER TO THIRD. SOME TRENDS OF MODELS SUGGESTING THAT WARM AIR MAY SNEAK FURTHER NORTH. THE MAJORITY OF THE 9Z SREF MEMBERS HAS TRANSITION AREA FROM PERU TO WARSAW TO SOUTH OF HILLSDALE WHERE A BIT OF EVERYTHING MAY OCCUR...MAINLY SNOW NORTH OF THIS AND POTENTIAL FOR HEADLINE SLEET/ICE ACCUMULATIONS IN THE SE. AT THIS POINT ENOUGH GOING ON PRIOR TO THIS SYSTEM AND STILL SOME UNCERTAINTY HOW THIS EVOLVES SO WILL MAKE SOME CHANGES TO THE HWO TO INCREASE AWARENESS A BIT MORE. AFTER THIS PERIOD THINGS BECOME EVEN MORE QUESTIONABLE WITH NEXT WAVE TO ARRIVE LATE WEDS NGT INTO THURS AND THURS NGT. MODELS VARY EVEN MORE THAN WITH FIRST MENTIONED SYSTEM WITH SOLUTIONS RANGING FROM SNOW FOR THE AREA...TO A MIXED BAG TO TEMPS WELL ABOVE FREEZING AND RAIN FOR THE AREA. AS A RESULT NO CHANGES MADE IN REGARDS TO THIS SYSTEM. YET ANOTHER ARCTIC BLAST MAY ARRIVE FOR THE END OF THE PERIOD RESULTING A CHANCE FOR SYNOPTIC SNOW FOLLOWED BY LAKE EFFECT PRECIP. WITH THE PATTERN SO CHAOTIC RIGHT NOW...FELT HOLDING A DRY FORECAST FOR SUNDAY WAS IN ORDER. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR INZ003>009- 012>018-020-022>027-032>034. MI...WIND ADVISORY UNTIL 10 AM EST MONDAY FOR MIZ077>081. OH...WIND ADVISORY UNTIL 10 AM EST MONDAY FOR OHZ001-002-004-005-015- 016-024-025. LM...GALE WARNING UNTIL 3 PM EST MONDAY FOR LMZ043-046. && $$ SHORT TERM...REHBEIN LONG TERM...FISHER AVIATION...TAYLOR UPDATE...TAYLOR in AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1135 AM CST SUN DEC 14 2008 UPDATED AVIATION DISCUSSION .UPDATE /TODAY/... COLD FRONT MOVING QUICKER THAN SCHEDULED THROUGH CENTRAL IOWA HAS RESULTED IN A COUPLE OF UPDATE CYCLES THIS MORNING. THE LEADING EDGE OF THE ARCTIC AIR IS NOW FROM NEAR MASON CITY TO MARSHALLTOWN TO CORYDON. WINDS SHIFT TO THE WEST NORTHWEST BEHIND THE FRONT AND STRATUS FILLS IN. FLURRIES OR VERY LIGHT SNOW WILL SPREAD ACROSS CENTRAL IOWA THIS AFTERNOON...BUT PROBABLY WON`T AMOUNT TO MUCH ACCUMULATION. TEMPERATURES WILL DROP 25 TO 30 DEGREES IN THE HOUR AFTER THE FRONT PASSES...THEN CONTINUE A SLOWER DROP THROUGH TONIGHT. DUE TO FASTER ARRIVAL OF VERY COLD TEMPERATURES ACROSS NORTHWEST IOWA...HAD TO MAKE WIND CHILL ADVISORY IN EFFECT EARLIER THAN PREVIOUS HEADLINE INDICATED. HAVE GONE WITH A START TIME OF NOON FOR NORTHWEST TIER...AND 6 PM FOR A TIER OF COUNTIES TO THE EAST OF THAT. ALL OTHER HEADLINES REMAIN UNCHANGED. && .SHORT TERM /TODAY/... EVOLUTION OF TEMPS/DEWPOINT...WIND AND PRECIP POTENTIAL OBVIOUSLY MAIN QUESTIONS TODAY. AS IS OFTEN THE CASE WITH SYSTEMS OF THIS STRENGTH...MODELS ARE NOT CAPTURING TEMP GRADIENT WELL ON EITHER END OF THE EXTREME. NAM AND ESPECIALLY RUC ARE DOING THE BEST AND WILL BE FOLLOWED. THIS RESULTS IN WARMER TEMPS THAN PREVIOUSLY ANTICIPATED AHEAD OF FROPA...WHICH SHOULD MAINLY AFFECT AREA 15-21Z...AND COOLER/DRIER CONDITIONS BEHIND. WITH SHARPLY INCREASING MSLP GRADIENT AND ISALLOBARIC MAX BEHIND SYSTEM...EXPECT WINDS TO JUST ECLIPSE SUSTAINED 30 MPH CRITERIA THIS AFTERNOON AND EARLY EVE SO WIND ADVY WILL BE IN EFFECT FOR SMALL PARTS OF WRN/NW SECTIONS. WITH COLD AIR SURGE AND MIXED LAYER FAIRLY SHALLOW /500M/ DO NOT EXPECT MUCH MORE THAN THAT WITH GUSTS. MODEL HAVE BEEN CONSISTENT SPITTING OUT LIGHT QPF WITH THE PASSAGE OF THIS SYSTEM. HOWEVER THIS MUST BE FROM SHALLOW MOISTURE AS SOUNDINGS SHOW LITTLE ABOVE 2KM. THIS IS SOMEWHAT OF A CONCERN HOWEVER BECAUSE MODELS HAVE BEEN EMPHATIC DEVELOPING THIS LOW STRATUS BUT NO SIGNS YET...CIGS STILL 2500FT OR HIGHER. CONSIDERING 40+ DEWPOINTS ARE SURGING INTO IA...STILL EXPECT THIS TO HAPPEN BUT MAY TAKE LONGER THAN MODELS DEPICT. THUS STILL HAVE CHANCE/LOW END LIKELY POPS...BUT THIS IS MAINLY DUE TO MEASURABLE DRIZZLE MORE THAN RAIN. P-TYPE MAY CHANGE TO LIGHT FRZG RAIN OR FRZG DRZL BEHIND FROPA AND THEN POSSIBLY TO LIGHT SNOW/FLURRIES AS DENDRITIC MOISTURE INCREASES BEHIND FRONT. DGZ WILL BE QUITE SHALLOW...NO HIGHER THAN 1.5KM BY LATE AFTERNOON. QPF VERY MINIMAL SO NO SIGNIFICANT CONCERNS OR HEADLINES IN THAT REGARD. .LONG TERM /TONIGHT-SATURDAY/... STRONG ARCTIC FRONT TO BE NEARLY EAST OF THE AREA BY EARLY TONIGHT BUT PLENTY OF DETAILS TO SORT OUT AS IT PASSES. MODELS CONTINUE TO HINT AT A SECONDARY BAND OF PRECIP JUST BEHIND THE BOUNDARY WITH SOME FRONTOGENETICAL FORCING BETWEEN H750-H600. FORCING AND QPF COMBINED SHOULD RESULT IN A BAND OF ONE TO ONE AND ONE HALF INCH OF SNOW ACROSS THE SOUTHEAST DURING THE EARLY EVENING HOURS. WINDS ALREADY PICKING UP BY THEN...SO WILL BE LOOKING AT RATHER POOR CONDITIONS FOR A BRIEF TIME THERE WITH LOW VSBYS AND BLOWING SNOW. WILL NOT ISSUE ANY HEADLINES FOR POTENTIAL NOW GIVEN THE NUMBER OF OTHER CONCERNS TODAY AND TONIGHT. THAT BEING SAID...DAY SHIFT WILL HAVE TO WATCH FOR POSSIBLE WINTER WEATHER CONDITIONS THERE LATER TODAY. NEXT CONCERN IS THE WIND CHILL FOR TONIGHT. MODELS SETTLING IN ON COLDER OVERNIGHT LOWS WITH H850 TEMPS BRUSHING -20C ACROSS THE FAR NORTH/EURO AND EVEN COLDER/GFS. UPSTREAM READINGS OF -10F OR LOWER TONIGHT WHERE -20C WAS LOCATED OVER THE NORTHERN DAKOTAS LATE LAST NIGHT. FEEL MORE CONFIDENT WITH MINS OF NEARLY -10F ACROSS THE NORTH TONIGHT AND NEARING ZERO CENTRAL. WINDS WILL MIX AS THE EVENING PROGRESSES WITH 30 TO 35 MPH GUSTS AND SUSTAINED 25 TO 30 MPH. THIS WILL PULL WIND CHILLS DOWN TO -20F OR LOWER FROM HIGHWAY 92 NORTH THROUGH AT LEAST 18Z MONDAY. NORTH OF HIGHWAY 20...AM EXPECTING WIND CHILL READINGS TO REMAIN BELOW CRITERIA MOST OF MONDAY AND WILL EXTEND THE ADVISORY THERE ALL DAY. SUBSIDENCE RATHER STRONG AS TONIGHT PROGRESSES...RESULTING IN CLEARING MOST AREAS AS HIGH BUILDS IN FOR MONDAY AFTERNOON. WINDS MONDAY WILL MIX BUT DIMINISH DURING THE DAY AS THE RIDGE FILES THROUGH THE AREA. DAY TIME HIGHS WILL BE VERY COLD...ONLY IN THE SINGLE DIGITS TO MID TEENS. ANOTHER VERY COLD NIGHT IS EXPECTED MONDAY NIGHT BUT CLOUD COVER FROM APPROACHING SYSTEM WILL CAP DROP-OFF WEST AND SOUTH. WATER VAPOR IMAGERY CONTINUES TO SHOW PRONOUNCED TROUGH OVER THE WEST COAST TONIGHT WITH NUMEROUS WAVES PROPAGATING EAST. MODELS HAVE BEEN ADVERTISING A DECENT OVERRUNNING EVENT FOR TUESDAY FOR THE PAST TWO TO THREE DAYS. STRONG BAROCLINIC ZONE IN PLACE WITH QUICK MOVING H500 WAVE AND MODEST MOISTURE TRANSPORT AT H850 WITH 20 TO 25KT WINDS WILL PROMOTE A LARGE AREA OF SNOWFALL ACROSS IOWA TUESDAY. CURRENT INDICATIONS ARE THAT CONVECTIVE ENHANCEMENT WILL NOT BE A MAJOR ISSUE...THOUGH SLIGHTLY NEG EPV VALUES ARE FORECAST. BUT EVEN WITH THAT...SNOWFALL RATIOS OF 17:20:1 AND MODEST LIFT IN THE SNOW GROWTH ZONE DURING THE DAY SHOULD HELP PRODUCE MODERATE TO POSSIBLE HEAVY SNOWFALL ACCUMULATIONS BETWEEN EARLY AM HOURS SOUTHWEST...TOWARD EAST CENTRAL SECTIONS BY LATE AFTERNOON. MOISTURE AMOUNTS POINTING TOWARD .25 TO .40 MAX...SO SNOWFALL MAY BE SIGNIFICANT. THE EURO HAS BEEN MOST CONSISTENT WITH THIS FEATURE THE PAST TWO DAYS. WIND DOES NOT LOOK TO BE A MAJOR FACTOR FOR NOW...BUT MAY IMPACT BLOWING TO SOME DEGREE. IF THIS ISNT ENOUGH FOR NOW ...MODELS EJECT ANOTHER SYSTEM TOWARD THE AREA ON THURSDAY. BY MIDWEEK THE DEEP COLD AIR MASS OVER THE REGION HAS BEEN DISPLACED SOMEWHAT NORTH. THIS WILL SET THE STAGE FOR A MIXED EVENT ON THURSDAY. EURO IS STILL COLDER THAN THE GFS WHICH MAY BE SHOWING A MORE NORTHERLY BIAS WITH THE DISPLACEMENT OF THE COLD AIR. BOTH GFS AND EURO SUGGEST STRONG H850 MOISTURE TRANSPORT WITH THE GULF PRETTY MUCH WIDE OPEN. TOO EARLY TO WORRY ABOUT AMOUNTS...BUT THE SOUTH MAY EXPERIENCE A FZRA/SN MIX WHILE CENTRAL AND AREAS NORTH APPEAR TO BE ALL SNOW. EURO A BIT MORE GENEROUS ON QPF WITH .50 TO .75 FOR THE 14/00Z RUN WHILE THE GFS IS CLOSER TO .25 TO .50 AT 14/00Z. ONE OTHER THING TO CONSIDER IS THE POTENTIAL FOR CONVECTIVE PRECIP WITH THIS EVENT GIVEN THE STRENGTH OF THE WIND FIELD. PLENTY OF TIME TO TRACK THIS EVENT LATER...BUT HAS THE POTENTIAL TO BE SIGNIFICANT. INTO THE WEEKEND ANOTHER SHOT OF ARCTIC AIR IS EXPECTED TO DROP SOUTHEAST. GIVEN THE CURRENT MODEL FORECAST AIRMASS...WEEKEND MAX AND MINS WILL PROBABLY NEED MODEST DOWNWARD ADJUSTMENT ONCE SNOW COVER IS REESTABLISHED OVER THE AREA AND DEPTH BECOMES REALIZED BY REPORTS. && .AVIATION...14/12Z AVIATION CONCERNS NOW TURN TO STRONG WINDS...AND SECONDARILY THE MVFR CEILINGS AND LIGHT SNOW. COLD FRONT WILL BE THRU ALO AND OTM RIGHT AROUND 18Z. ALL TAF SITES WILL THEN BE IN STRONG WNW FLOW WITH SUSTAINED SPEEDS IN EXCESS OF 20 KTS AND GUSTS 28 TO 35 KTS THRU 12Z. NOT MUCH FORCING FOR MORE THAN OCCASIONAL LIGHT AND FINE SNOWFALL...EXCEPT AT KOTM WHERE THERE WILL BE A PERIOD OF 4 TO 5 HOURS THIS EVENING AS FORCING INCREASES ENOUGH TO LIKELY PRODUCE ACCUMULATING SNOWFALL. THERE IS STILL UNCERTAINTY REGARDING HOW LOW CEILINGS AND VSBY WILL BE IN THIS SNOW. HAVE LEFT THEM IN MVFR FOR NOW. ALL SITES GO VFR BY 11Z WITH DIMINISHING WIND. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST MONDAY FOR ADAIR-BLACK HAWK-CASS-DALLAS-GRUNDY-HARDIN-JASPER-MADISON- MAHASKA-MARION-MARSHALL-POLK-POWESHIEK-STORY-TAMA-WARREN. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR AUDUBON-CALHOUN- CARROLL-CASS-CRAWFORD-EMMET-HUMBOLDT-KOSSUTH-PALO ALTO- POCAHONTAS-SAC. WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 12 PM CST MONDAY FOR AUDUBON-BOONE-GREENE-GUTHRIE-HAMILTON-WEBSTER. WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR EMMET-PALO ALTO- POCAHONTAS. WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST MONDAY FOR CERRO GORDO-FRANKLIN-HANCOCK-HUMBOLDT-KOSSUTH-WINNEBAGO- WORTH-WRIGHT. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR BREMER-BUTLER. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR CALHOUN-CARROLL- CRAWFORD-SAC. && $$ UPDATE...MOYER SHORT TERM...SMALL LONG TERM...REV AVIATION...MOYER ia AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1052 AM CST SUN DEC 14 2008 .UPDATE /TODAY/... COLD FRONT MOVING QUICKER THAN SCHEDULED THROUGH CENTRAL IOWA HAS RESULTED IN A COUPLE OF UPDATE CYCLES THIS MORNING. THE LEADING EDGE OF THE ARCTIC AIR IS NOW FROM NEAR MASON CITY TO MARSHALLTOWN TO CORYDON. WINDS SHIFT TO THE WEST NORTHWEST BEHIND THE FRONT AND STRATUS FILLS IN. FLURRIES OR VERY LIGHT SNOW WILL SPREAD ACROSS CENTRAL IOWA THIS AFTERNOON...BUT PROBABLY WON`T AMOUNT TO MUCH ACCUMULATION. TEMPERATURES WILL DROP 25 TO 30 DEGREES IN THE HOUR AFTER THE FRONT PASSES...THEN CONTINUE A SLOWER DROP THROUGH TONIGHT. DUE TO FASTER ARRIVAL OF VERY COLD TEMPERATURES ACROSS NORTHWEST IOWA...HAD TO MAKE WIND CHILL ADVISORY IN EFFECT EARLIER THAN PREVIOUS HEADLINE INDICATED. HAVE GONE WITH A START TIME OF NOON FOR NORTHWEST TIER...AND 6 PM FOR A TIER OF COUNTIES TO THE EAST OF THAT. ALL OTHER HEADLINES REMAIN UNCHANGED. && .SHORT TERM /TODAY/... EVOLUTION OF TEMPS/DEWPOINT...WIND AND PRECIP POTENTIAL OBVIOUSLY MAIN QUESTIONS TODAY. AS IS OFTEN THE CASE WITH SYSTEMS OF THIS STRENGTH...MODELS ARE NOT CAPTURING TEMP GRADIENT WELL ON EITHER END OF THE EXTREME. NAM AND ESPECIALLY RUC ARE DOING THE BEST AND WILL BE FOLLOWED. THIS RESULTS IN WARMER TEMPS THAN PREVIOUSLY ANTICIPATED AHEAD OF FROPA...WHICH SHOULD MAINLY AFFECT AREA 15-21Z...AND COOLER/DRIER CONDITIONS BEHIND. WITH SHARPLY INCREASING MSLP GRADIENT AND ISALLOBARIC MAX BEHIND SYSTEM...EXPECT WINDS TO JUST ECLIPSE SUSTAINED 30 MPH CRITERIA THIS AFTERNOON AND EARLY EVE SO WIND ADVY WILL BE IN EFFECT FOR SMALL PARTS OF WRN/NW SECTIONS. WITH COLD AIR SURGE AND MIXED LAYER FAIRLY SHALLOW /500M/ DO NOT EXPECT MUCH MORE THAN THAT WITH GUSTS. MODEL HAVE BEEN CONSISTENT SPITTING OUT LIGHT QPF WITH THE PASSAGE OF THIS SYSTEM. HOWEVER THIS MUST BE FROM SHALLOW MOISTURE AS SOUNDINGS SHOW LITTLE ABOVE 2KM. THIS IS SOMEWHAT OF A CONCERN HOWEVER BECAUSE MODELS HAVE BEEN EMPHATIC DEVELOPING THIS LOW STRATUS BUT NO SIGNS YET...CIGS STILL 2500FT OR HIGHER. CONSIDERING 40+ DEWPOINTS ARE SURGING INTO IA...STILL EXPECT THIS TO HAPPEN BUT MAY TAKE LONGER THAN MODELS DEPICT. THUS STILL HAVE CHANCE/LOW END LIKELY POPS...BUT THIS IS MAINLY DUE TO MEASURABLE DRIZZLE MORE THAN RAIN. P-TYPE MAY CHANGE TO LIGHT FRZG RAIN OR FRZG DRZL BEHIND FROPA AND THEN POSSIBLY TO LIGHT SNOW/FLURRIES AS DENDRITIC MOISTURE INCREASES BEHIND FRONT. DGZ WILL BE QUITE SHALLOW...NO HIGHER THAN 1.5KM BY LATE AFTERNOON. QPF VERY MINIMAL SO NO SIGNIFICANT CONCERNS OR HEADLINES IN THAT REGARD. .LONG TERM /TONIGHT-SATURDAY/... STRONG ARCTIC FRONT TO BE NEARLY EAST OF THE AREA BY EARLY TONIGHT BUT PLENTY OF DETAILS TO SORT OUT AS IT PASSES. MODELS CONTINUE TO HINT AT A SECONDARY BAND OF PRECIP JUST BEHIND THE BOUNDARY WITH SOME FRONTOGENETICAL FORCING BETWEEN H750-H600. FORCING AND QPF COMBINED SHOULD RESULT IN A BAND OF ONE TO ONE AND ONE HALF INCH OF SNOW ACROSS THE SOUTHEAST DURING THE EARLY EVENING HOURS. WINDS ALREADY PICKING UP BY THEN...SO WILL BE LOOKING AT RATHER POOR CONDITIONS FOR A BRIEF TIME THERE WITH LOW VSBYS AND BLOWING SNOW. WILL NOT ISSUE ANY HEADLINES FOR POTENTIAL NOW GIVEN THE NUMBER OF OTHER CONCERNS TODAY AND TONIGHT. THAT BEING SAID...DAY SHIFT WILL HAVE TO WATCH FOR POSSIBLE WINTER WEATHER CONDITIONS THERE LATER TODAY. NEXT CONCERN IS THE WIND CHILL FOR TONIGHT. MODELS SETTLING IN ON COLDER OVERNIGHT LOWS WITH H850 TEMPS BRUSHING -20C ACROSS THE FAR NORTH/EURO AND EVEN COLDER/GFS. UPSTREAM READINGS OF -10F OR LOWER TONIGHT WHERE -20C WAS LOCATED OVER THE NORTHERN DAKOTAS LATE LAST NIGHT. FEEL MORE CONFIDENT WITH MINS OF NEARLY -10F ACROSS THE NORTH TONIGHT AND NEARING ZERO CENTRAL. WINDS WILL MIX AS THE EVENING PROGRESSES WITH 30 TO 35 MPH GUSTS AND SUSTAINED 25 TO 30 MPH. THIS WILL PULL WIND CHILLS DOWN TO -20F OR LOWER FROM HIGHWAY 92 NORTH THROUGH AT LEAST 18Z MONDAY. NORTH OF HIGHWAY 20...AM EXPECTING WIND CHILL READINGS TO REMAIN BELOW CRITERIA MOST OF MONDAY AND WILL EXTEND THE ADVISORY THERE ALL DAY. SUBSIDENCE RATHER STRONG AS TONIGHT PROGRESSES...RESULTING IN CLEARING MOST AREAS AS HIGH BUILDS IN FOR MONDAY AFTERNOON. WINDS MONDAY WILL MIX BUT DIMINISH DURING THE DAY AS THE RIDGE FILES THROUGH THE AREA. DAY TIME HIGHS WILL BE VERY COLD...ONLY IN THE SINGLE DIGITS TO MID TEENS. ANOTHER VERY COLD NIGHT IS EXPECTED MONDAY NIGHT BUT CLOUD COVER FROM APPROACHING SYSTEM WILL CAP DROP-OFF WEST AND SOUTH. WATER VAPOR IMAGERY CONTINUES TO SHOW PRONOUNCED TROUGH OVER THE WEST COAST TONIGHT WITH NUMEROUS WAVES PROPAGATING EAST. MODELS HAVE BEEN ADVERTISING A DECENT OVERRUNNING EVENT FOR TUESDAY FOR THE PAST TWO TO THREE DAYS. STRONG BAROCLINIC ZONE IN PLACE WITH QUICK MOVING H500 WAVE AND MODEST MOISTURE TRANSPORT AT H850 WITH 20 TO 25KT WINDS WILL PROMOTE A LARGE AREA OF SNOWFALL ACROSS IOWA TUESDAY. CURRENT INDICATIONS ARE THAT CONVECTIVE ENHANCEMENT WILL NOT BE A MAJOR ISSUE...THOUGH SLIGHTLY NEG EPV VALUES ARE FORECAST. BUT EVEN WITH THAT...SNOWFALL RATIOS OF 17:20:1 AND MODEST LIFT IN THE SNOW GROWTH ZONE DURING THE DAY SHOULD HELP PRODUCE MODERATE TO POSSIBLE HEAVY SNOWFALL ACCUMULATIONS BETWEEN EARLY AM HOURS SOUTHWEST...TOWARD EAST CENTRAL SECTIONS BY LATE AFTERNOON. MOISTURE AMOUNTS POINTING TOWARD .25 TO .40 MAX...SO SNOWFALL MAY BE SIGNIFICANT. THE EURO HAS BEEN MOST CONSISTENT WITH THIS FEATURE THE PAST TWO DAYS. WIND DOES NOT LOOK TO BE A MAJOR FACTOR FOR NOW...BUT MAY IMPACT BLOWING TO SOME DEGREE. IF THIS ISNT ENOUGH FOR NOW ...MODELS EJECT ANOTHER SYSTEM TOWARD THE AREA ON THURSDAY. BY MIDWEEK THE DEEP COLD AIR MASS OVER THE REGION HAS BEEN DISPLACED SOMEWHAT NORTH. THIS WILL SET THE STAGE FOR A MIXED EVENT ON THURSDAY. EURO IS STILL COLDER THAN THE GFS WHICH MAY BE SHOWING A MORE NORTHERLY BIAS WITH THE DISPLACEMENT OF THE COLD AIR. BOTH GFS AND EURO SUGGEST STRONG H850 MOISTURE TRANSPORT WITH THE GULF PRETTY MUCH WIDE OPEN. TOO EARLY TO WORRY ABOUT AMOUNTS...BUT THE SOUTH MAY EXPERIENCE A FZRA/SN MIX WHILE CENTRAL AND AREAS NORTH APPEAR TO BE ALL SNOW. EURO A BIT MORE GENEROUS ON QPF WITH .50 TO .75 FOR THE 14/00Z RUN WHILE THE GFS IS CLOSER TO .25 TO .50 AT 14/00Z. ONE OTHER THING TO CONSIDER IS THE POTENTIAL FOR CONVECTIVE PRECIP WITH THIS EVENT GIVEN THE STRENGTH OF THE WIND FIELD. PLENTY OF TIME TO TRACK THIS EVENT LATER...BUT HAS THE POTENTIAL TO BE SIGNIFICANT. INTO THE WEEKEND ANOTHER SHOT OF ARCTIC AIR IS EXPECTED TO DROP SOUTHEAST. GIVEN THE CURRENT MODEL FORECAST AIRMASS...WEEKEND MAX AND MINS WILL PROBABLY NEED MODEST DOWNWARD ADJUSTMENT ONCE SNOW COVER IS REESTABLISHED OVER THE AREA AND DEPTH BECOMES REALIZED BY REPORTS. && .AVIATION...14/12Z VERY CHANGEABLE WEATHER CONDITIONS TODAY. MVFR CIGS SHOULD GRADUALLY LOWER IN SLY FLOW WITH SOME POTENTIAL TO GO IFR BUT THAT IS NOT INCLUDED IN THE FORECAST AT THE MOMENT. PATCHY DRIZZLE MAY OCCUR AS WELL. STRONG COLD FRONT WILL THEN AFFECT SITES 14-19Z WITH WINDS BECOMING NWLY AND SUSTAINED SPEEDS EXCEEDING 20KTS. IFR CLOUDS WILL BRIEFLY OCCUR WITH COLD AIR SURGE BEFORE LIFTING BACK TO MVFR FOR A PROLONGED PERIOD. INCREASING CROSSWINDS...20KTS OR MORE...MAY OCCUR MAINLY AT SW-NE RUNWAYS. FLURRIES MAY OCCUR WELL BEHIND THE FRONT TOO AND THERE IS SOME POTENTIAL FOR BRIEF FREEZING DRIZZLE...BUT THREAT NOT ENOUGH TO INCLUDE. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST MONDAY FOR ADAIR-BLACK HAWK-CASS-DALLAS-GRUNDY-HARDIN-JASPER-MADISON- MAHASKA-MARION-MARSHALL-POLK-POWESHIEK-STORY-TAMA-WARREN. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR AUDUBON-CALHOUN- CARROLL-CASS-CRAWFORD-EMMET-HUMBOLDT-KOSSUTH-PALO ALTO- POCAHONTAS-SAC. WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 12 PM CST MONDAY FOR AUDUBON-BOONE-GREENE-GUTHRIE-HAMILTON-WEBSTER. WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR EMMET-PALO ALTO- POCAHONTAS. WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST MONDAY FOR CERRO GORDO-FRANKLIN-HANCOCK-HUMBOLDT-KOSSUTH-WINNEBAGO- WORTH-WRIGHT. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR BREMER-BUTLER. WIND CHILL ADVISORY UNTIL 12 PM CST MONDAY FOR CALHOUN-CARROLL- CRAWFORD-SAC. && $$ UPDATE...MOYER SHORT TERM...SMALL LONG TERM...REV AVIATION...SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 602 AM CST SUN DEC 14 2008 .SYNOPSIS... 08Z SFC ANLYS PLACES SFC LOW BETWEEN HSI-LNK WITH TRAILING COLD FRONT ACROSS KS INTO CO. WRMFNT EXTENDS FROM LOW INTO SRN MN AND WI WITH ARCTIC FRONT DRAPED ACROSS MN APPROACHING FSD. STRONG CAA AND PRES RISES BEHIND SYSTEM WITH NEARLY 40F CHANGE ACROSS FRONT BETWEEN ONL-FNB. SEVERAL SHORT WAVES NOTED IN SWLY FLOW AHEAD OF ROCKIES TROUGH...BUT GLANCING US TO THE NW WITH MUCH OF FORCING FROM SIOUXLAND AREA W AND N. && .SHORT TERM...TODAY EVOLUTION OF TEMPS/DEWPOINT...WIND AND PRECIP POTENTIAL OBVIOUSLY MAIN QUESTIONS TODAY. AS IS OFTEN THE CASE WITH SYSTEMS OF THIS STRENGTH...MODELS ARE NOT CAPTURING TEMP GRADIENT WELL ON EITHER END OF THE EXTREME. NAM AND ESPECIALLY RUC ARE DOING THE BEST AND WILL BE FOLLOWED. THIS RESULTS IN WARMER TEMPS THAN PREVIOUSLY ANTICIPATED AHEAD OF FROPA...WHICH SHOULD MAINLY AFFECT AREA 15-21Z...AND COOLER/DRIER CONDITIONS BEHIND. WITH SHARPLY INCREASING MSLP GRADIENT AND ISALLOBARIC MAX BEHIND SYSTEM...EXPECT WINDS TO JUST ECLIPSE SUSTAINED 30 MPH CRITERIA THIS AFTERNOON AND EARLY EVE SO WIND ADVY WILL BE IN EFFECT FOR SMALL PARTS OF WRN/NW SECTIONS. WITH COLD AIR SURGE AND MIXED LAYER FAIRLY SHALLOW /500M/ DO NOT EXPECT MUCH MORE THAN THAT WITH GUSTS. MODEL HAVE BEEN CONSISTENT SPITTING OUT LIGHT QPF WITH THE PASSAGE OF THIS SYSTEM. HOWEVER THIS MUST BE FROM SHALLOW MOISTURE AS SOUNDINGS SHOW LITTLE ABOVE 2KM. THIS IS SOMEWHAT OF A CONCERN HOWEVER BECAUSE MODELS HAVE BEEN EMPHATIC DEVELOPING THIS LOW STRATUS BUT NO SIGNS YET...CIGS STILL 2500FT OR HIGHER. CONSIDERING 40+ DEWPOINTS ARE SURGING INTO IA...STILL EXPECT THIS TO HAPPEN BUT MAY TAKE LONGER THAN MODELS DEPICT. THUS STILL HAVE CHANCE/LOW END LIKELY POPS...BUT THIS IS MAINLY DUE TO MEASURABLE DRIZZLE MORE THAN RAIN. P-TYPE MAY CHANGE TO LIGHT FRZG RAIN OR FRZG DRZL BEHIND FROPA AND THEN POSSIBLY TO LIGHT SNOW/FLURRIES AS DENDRITIC MOISTURE INCREASES BEHIND FRONT. DGZ WILL BE QUITE SHALLOW...NO HIGHER THAN 1.5KM BY LATE AFTERNOON. QPF VERY MINIMAL SO NO SIGNIFICANT CONCERNS OR HEADLINES IN THAT REGARD. .LONG TERM...TONIGHT THROUGH SATURDAY STRONG ARCTIC FRONT TO BE NEARLY EAST OF THE AREA BY EARLY TONIGHT BUT PLENTY OF DETAILS TO SORT OUT AS IT PASSES. MODELS CONTINUE TO HINT AT A SECONDARY BAND OF PRECIP JUST BEHIND THE BOUNDARY WITH SOME FRONTOGENETICAL FORCING BETWEEN H750-H600. FORCING AND QPF COMBINED SHOULD RESULT IN A BAND OF ONE TO ONE AND ONE HALF INCH OF SNOW ACROSS THE SOUTHEAST DURING THE EARLY EVENING HOURS. WINDS ALREADY PICKING UP BY THEN...SO WILL BE LOOKING AT RATHER POOR CONDITIONS FOR A BRIEF TIME THERE WITH LOW VSBYS AND BLOWING SNOW. WILL NOT ISSUE ANY HEADLINES FOR POTENTIAL NOW GIVEN THE NUMBER OF OTHER CONCERNS TODAY AND TONIGHT. THAT BEING SAID...DAY SHIFT WILL HAVE TO WATCH FOR POSSIBLE WINTER WEATHER CONDITIONS THERE LATER TODAY. NEXT CONCERN IS THE WIND CHILL FOR TONIGHT. MODELS SETTLING IN ON COLDER OVERNIGHT LOWS WITH H850 TEMPS BRUSHING -20C ACROSS THE FAR NORTH/EURO AND EVEN COLDER/GFS. UPSTREAM READINGS OF -10F OR LOWER TONIGHT WHERE -20C WAS LOCATED OVER THE NORTHERN DAKOTAS LATE LAST NIGHT. FEEL MORE CONFIDENT WITH MINS OF NEARLY -10F ACROSS THE NORTH TONIGHT AND NEARING ZERO CENTRAL. WINDS WILL MIX AS THE EVENING PROGRESSES WITH 30 TO 35 MPH GUSTS AND SUSTAINED 25 TO 30 MPH. THIS WILL PULL WIND CHILLS DOWN TO -20F OR LOWER FROM HIGHWAY 92 NORTH THROUGH AT LEAST 18Z MONDAY. NORTH OF HIGHWAY 20...AM EXPECTING WIND CHILL READINGS TO REMAIN BELOW CRITERIA MOST OF MONDAY AND WILL EXTEND THE ADVISORY THERE ALL DAY. SUBSIDENCE RATHER STRONG AS TONIGHT PROGRESSES...RESULTING IN CLEARING MOST AREAS AS HIGH BUILDS IN FOR MONDAY AFTERNOON. WINDS MONDAY WILL MIX BUT DIMINISH DURING THE DAY AS THE RIDGE FILES THROUGH THE AREA. DAY TIME HIGHS WILL BE VERY COLD...ONLY IN THE SINGLE DIGITS TO MID TEENS. ANOTHER VERY COLD NIGHT IS EXPECTED MONDAY NIGHT BUT CLOUD COVER FROM APPROACHING SYSTEM WILL CAP DROP-OFF WEST AND SOUTH. WATER VAPOR IMAGERY CONTINUES TO SHOW PRONOUNCED TROUGH OVER THE WEST COAST TONIGHT WITH NUMEROUS WAVES PROPAGATING EAST. MODELS HAVE BEEN ADVERTISING A DECENT OVERRUNNING EVENT FOR TUESDAY FOR THE PAST TWO TO THREE DAYS. STRONG BAROCLINIC ZONE IN PLACE WITH QUICK MOVING H500 WAVE AND MODEST MOISTURE TRANSPORT AT H850 WITH 20 TO 25KT WINDS WILL PROMOTE A LARGE AREA OF SNOWFALL ACROSS IOWA TUESDAY. CURRENT INDICATIONS ARE THAT CONVECTIVE ENHANCEMENT WILL NOT BE A MAJOR ISSUE...THOUGH SLIGHTLY NEG EPV VALUES ARE FORECAST. BUT EVEN WITH THAT...SNOWFALL RATIOS OF 17:20:1 AND MODEST LIFT IN THE SNOW GROWTH ZONE DURING THE DAY SHOULD HELP PRODUCE MODERATE TO POSSIBLE HEAVY SNOWFALL ACCUMULATIONS BETWEEN EARLY AM HOURS SOUTHWEST...TOWARD EAST CENTRAL SECTIONS BY LATE AFTERNOON. MOISTURE AMOUNTS POINTING TOWARD .25 TO .40 MAX...SO SNOWFALL MAY BE SIGNIFICANT. THE EURO HAS BEEN MOST CONSISTENT WITH THIS FEATURE THE PAST TWO DAYS. WIND DOES NOT LOOK TO BE A MAJOR FACTOR FOR NOW...BUT MAY IMPACT BLOWING TO SOME DEGREE. IF THIS ISNT ENOUGH FOR NOW ...MODELS EJECT ANOTHER SYSTEM TOWARD THE AREA ON THURSDAY. BY MIDWEEK THE DEEP COLD AIR MASS OVER THE REGION HAS BEEN DISPLACED SOMEWHAT NORTH. THIS WILL SET THE STAGE FOR A MIXED EVENT ON THURSDAY. EURO IS STILL COLDER THAN THE GFS WHICH MAY BE SHOWING A MORE NORTHERLY BIAS WITH THE DISPLACEMENT OF THE COLD AIR. BOTH GFS AND EURO SUGGEST STRONG H850 MOISTURE TRANSPORT WITH THE GULF PRETTY MUCH WIDE OPEN. TOO EARLY TO WORRY ABOUT AMOUNTS...BUT THE SOUTH MAY EXPERIENCE A FZRA/SN MIX WHILE CENTRAL AND AREAS NORTH APPEAR TO BE ALL SNOW. EURO A BIT MORE GENEROUS ON QPF WITH .50 TO .75 FOR THE 14/00Z RUN WHILE THE GFS IS CLOSER TO .25 TO .50 AT 14/00Z. ONE OTHER THING TO CONSIDER IS THE POTENTIAL FOR CONVECTIVE PRECIP WITH THIS EVENT GIVEN THE STRENGTH OF THE WIND FIELD. PLENTY OF TIME TO TRACK THIS EVENT LATER...BUT HAS THE POTENTIAL TO BE SIGNIFICANT. INTO THE WEEKEND ANOTHER SHOT OF ARCTIC AIR IS EXPECTED TO DROP SOUTHEAST. GIVEN THE CURRENT MODEL FORECAST AIRMASS...WEEKEND MAX AND MINS WILL PROBABLY NEED MODEST DOWNWARD ADJUSTMENT ONCE SNOW COVER IS REESTABLISHED OVER THE AREA AND DEPTH BECOMES REALIZED BY REPORTS. && .AVIATION...14/12Z VERY CHANGEABLE WEATHER CONDITIONS TODAY. MVFR CIGS SHOULD GRADUALLY LOWER IN SLY FLOW WITH SOME POTENTIAL TO GO IFR BUT THAT IS NOT INCLUDED IN THE FORECAST AT THE MOMENT. PATCHY DRIZZLE MAY OCCUR AS WELL. STRONG COLD FRONT WILL THEN AFFECT SITES 14-19Z WITH WINDS BECOMING NWLY AND SUSTAINED SPEEDS EXCEEDING 20KTS. IFR CLOUDS WILL BRIEFLY OCCUR WITH COLD AIR SURGE BEFORE LIFTING BACK TO MVFR FOR A PROLONGED PERIOD. INCREASING CROSSWINDS...20KTS OR MORE...MAY OCCUR MAINLY AT SW-NE RUNWAYS. FLURRIES MAY OCCUR WELL BEHIND THE FRONT TOO AND THERE IS SOME POTENTIAL FOR BRIEF FREEZING DRIZZLE...BUT THREAT NOT ENOUGH TO INCLUDE. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND ADVY THIS AFTERNOON AND EVE /18Z-03Z/ CASS-AUDUBON-CRAWFORD-CARROLL-SAC-CALHOUN-POCAHONTAS-HUMBOLDT- PALO ALTO-KOSSUTH-EMMET. WIND CHILL ADVY TONIGHT THROUGH MIDDAY MONDAY /06Z-18Z MONDAY/ SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD- CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS- POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA. WIND CHILL ADVY TONIGHT THROUGH MONDAY AFTERNOON /06Z-00Z TUESDAY/ EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER. && $$ SHORT TERM/AVIATION...BSS LONG TERM...REV ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 913 PM CST SUN DEC 14 2008 .UPDATE... UPDATING TO TWEAK TEMPS DOWN AND TO ISSUE WIND CHILL ADVISORY FOR CENTRAL KS. POCKETS OF SLEET HAVE MOVED OFF INTO MO WITH JUST SOME VERY LIGHT SNOW/FLURRIES LEFT OVER SE KS. UPSTREAM TEMPS CONTINUE TO LOOK VERY COLD WITH WINDS STAYING UP OVER THE AREA. AFTER UPDATING TEMPS AND WINDS...WIND CHILL GRIDS NOW HAVE SEVERAL HOURS OF -15 TEMPS OVER CENTRAL KS. THEREFORE WILL GO AHEAD AND MATCH UP WITH SURROUNDING OFFICES AND ISSUE AN ADVISORY THROUGH 14Z. LAWSON && .PREV DISCUSSION... /ISSUED 708 PM CST SUN DEC 14 2008/ UPDATE... UPDATED TO INCREASE PRECIP CHANCES OVER SE KS AND TO DECREASE OVER CENTRAL AND SOUTH CENTRAL KS. PRECIP HAS INCREASED IN COVERAGE AND INTENSITY OVER SE KS. WE HAVE RECIEVED A COUPLE REPORTS OF THUNDER SLEET OVER THE LAST HOUR WITH SOME SNOW LIKELY MIXED IN. PROFILERS INDICATE THAT THE 850MB FRONT IS STILL MAKING ITS WAY THROUGH SE KS WITH SOME WARM ADVECTION ALSO INDICATED AT 700MB. IN ADDITION WATER VAPOR IMAGERY STILL SHOWING SOME WEAK UPPER ENERGY SLIDING THROUGH. THE GOOD NEWS IS THAT THIS ACTIVITY IS ON THE MOVE AND SHOULD EXIT SE KS BY AROUND 9 PM. TOOK OUT POPS FOR LOCATIONS ALONG AND WEST OF 135 AND JUST WENT WITH SOME FLURRIES THROUGH 06Z. LAWSON PREV DISCUSSION... /ISSUED 543 PM CST SUN DEC 14 2008/ AVIATION...Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS WILL BE SOME LIGHT PRECIP FOR THE FIRE FEW HOURS ALONG WITH SOME GUSTY NORTH WINDS. CURRENTLY HAVE SOME LIGHT SNOW...MIXING BRIEFLY WITH LIGHT SLEET...AFFECTING LOCATIONS GENERALLY ALONG AND EAST OF I-135. THIS ACTIVITY IS EXPECTED TO MOVE QUICKLY EAST AND BE OUT OF SE KS BY AROUND 03Z. CIGS ARE EXPECTED TO GRADUALLY RISE WITH ABOVE MVFR HEIGHTS EXPECTED. THE EXCEPTION WILL BE AT KCNU WHERE SOME MVFR CIGS WILL LAST THROUGH AROUND 03Z. WINDS ARE EXPECTED TO GRADUALLY DECREASE THROUGH THE NIGHT BUT WILL REMAIN OUT OF THE NORTH. LAWSON PREV DISCUSSION... /ISSUED 332 PM CST SUN DEC 14 2008/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE WIND CHILL VALUES TONIGHT AND SNOW CHANCES ACROSS CENTRAL KANSAS MONDAY NIGHT AND TUESDAY MORNING. THE NEXT CONCERN WILL BE THE FREEZING DRIZZLE AND FREEZING RAIN POTENTIAL WEDNESDAY NIGHT INTO THURSDAY MORNING. TONIGHT: LATEST WATER VAPOR LOOP WAS SHOWING THE POTENTIAL VORTICITY ANOMALY MOVING THROUGH NORTHWEST KANSAS. LATEST PROFILERS/RUC WERE ALSO SHOWING A BAROCLINIC ZONE AROUND 700MB NEAR THAT AREA. LATEST RADAR LOOP WAS ALSO SHOWING SOME NARROW BANDS OF LIGHT SNOW DEVELOPING ACROSS SOUTHWEST KANSAS EXTENDING INTO CENTRAL KANSAS. THESE INSTABILITY BANDS OF SNOW ARE ASSOCIATED WITH STEEPER LAPSE RATES ABOVE 750MB. THESE BANDS APPEARS TO FAIRLY PROGRESSIVE WHICH WILL LIMIT ANY SNOWFALL ACCUMULATION. AS A RESULT...WE HAVE LOWERED SNOWFALL ACCUMULATIONS TO ONE HALF INCH OR LESS THIS EVENING. MEANWHILE...MODELS CONTINUE TO UNDERESTIMATE THE AMOUNT OF COLD AIR POURING INTO THE AREA. AS A RESULT...WE HAVE LOWERED TEMPERATURES A COUPLE MORE DEGREES FOR OVERNIGHT LOWS. THESE LOWER TEMPERATURES COMBINED WITH GUSTY NORTH WINDS AT 10 TO 20 MPH WILL PRODUCE WIND CHILL VALUES NEAR 15 BELOW ZERO FOR A COUPLE OF HOURS OVERNIGHT IN RUSSELL AND LINCOLN COUNTIES. AFTER COLLABORATING WITH SURROUNDING FORECAST OFFICES...WE HAVE ELECTED NOT ISSUE A WIND CHILL ADVISORY. ALTHOUGH...LATER SHIFTS MAY NEED CONSIDER THIS DEPENDING IF TEMPERATURES DROP LOWER THAN THE CURRENT FORECAST. MONDAY: THE ARCTIC HIGH WILL CONTINUE TO SLIDE EAST INTO THE UPPER MIDWEST. HOWEVER...THE POLAR AIR MASS WILL NOT BUDGE WITH HIGHS STRUGGLING TO GET OUT OF THE TEENS. WIND CHILL VALUES WILL GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT-TUESDAY: ANOTHER POTENTIAL VORTICITY ANOMALY IS EXPECTED TO RIDE THROUGH NORTHWEST KANSAS AGAIN ON MONDAY NIGHT. THE GFS SEEMS TO HAVE A GOOD HANDLE ON THIS FEATURE WITH THE WAVE CURRENTLY MOVING THROUGH THE PACIFIC NORTHWEST. THIS FEATURE SHOULD PROVIDE AMPLE ISENTROPIC LIFT BETWEEN 290-295K MAINLY OVER NORTHERN KANSAS AND SOUTHERN NEBRASKA LATE MONDAY NIGHT. FORTUNATELY...IT APPEARS LIKE MOST OF THE ACTIVITY SHOULD BE OF THE FROZEN VARIETY. SNOWFALL ACCUMULATIONS SHOULD GENERALLY BE LESS THAN ONE INCH WITH THE HIGHEST AMOUNTS EXPECTED IN RUSSELL...LINCOLN AND SALINE COUNTIES. TUESDAY NIGHT-THURSDAY NIGHT: THE UPPER LEVEL FLOW IS PROGGED TO REMAIN OUT OF THE SOUTHWEST WHICH WILL PROVIDE AN UNSETTLED PATTERN DURING THIS TIMEFRAME. THE MAIN QUESTION WILL BE THE POSITION OF THE ELEVATED BAROCLINIC ZONE. RIGHT NOW WE ARE FAVORING MORE OF THE ECMWF/GFS ENSEMBLES ON THE TIMING OF THE FEATURES MOVING FROM THE ROCKIES AND NORTHERN PLAINS. THE ECMWF AND GFS ENSEMBLES ARE A LITTLE MORE AMPLIFIED WITH A WAVE MOVING THROUGH THE NORTHERN PLAINS ON LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THIS WAVE WILL JUST HELP SHOVE THE SURFACE FRONTAL BOUNDARY SOUTH THROUGH THE FORECAST AREA AND BRING A SHOT OF MODIFIED CANADIAN AIR WITH LITTLE IF ANY PRECIP. HOWEVER...THE GFS ENSEMBLES/ECMWF/UKMET ARE PICKING UP ON A STRONGER WAVE MOVING OUT OF THE ROCKIES WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS TRENDING ON PLACING THIS FRONTAL BOUNDARY FURTHER SOUTH THAN PREVIOUS RUNS. THIS WOULD FAVOR MORE OF A FREEZING RAIN EVENT IF THIS PANS OUT. THE GFS ON THE OTHER HAND...PLACES THIS BOUNDARY FURTHER NORTH BISECTING CENTRAL KANSAS. AT THIS TIME...WE ARE FAVORING THE ECMWF SOLUTION WHICH KEEPS THIS BOUNDARY FURTHER SOUTH WHILE CYCLOGENESIS GETS GOING ACROSS THE ROCKIES. THIS TIMEFRAME WILL NEED TO BE WATCHED WITH LATER RUNS. FRIDAY-SUNDAY: THE GFS/ECMWF ARE BOTH SHOWING A 1042MB HIGH DEVELOPING OVER ALASKA WHICH MAY BUILD SOUTH INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY. AS A RESULT...MORE COLD WEATHER IS ON THE HORIZON THIS WEEKEND. COX AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ARCTIC COLD FRONT WILL CONTINUE MOVING THROUGH SOUTHEAST KANSAS EARLY THIS AFTERNOON. BLUSTERY AND OCCASIONALLY STRONG NORTH TO NORTHWEST WINDS BEHIND THE FRONT WILL CONTINUE ACROSS MUCH OF THE AREA INTO THE EVENING. A NARROW AND TRANSIENT BAND OF LIFT IS EXPECTED TO DEVELOP BEHIND THE FRONT LATE THIS AFTERNOON ACROSS CENTRAL KANSAS AND SHIFT SOUTH ACROSS THE REST OF THE AREA INTO THE EARLY EVENING. THIS MAY RESULT IN A BRIEF PERIOD OF LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE. MVFR CIGS WILL PREVAIL ACROSS THE AREA FOR MUCH OF THE FORECAST VALID PERIOD. KED && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 6 19 13 26 / 10 10 20 20 HUTCHINSON 5 18 11 24 / 10 10 30 20 NEWTON 6 17 13 24 / 10 10 30 30 ELDORADO 8 18 13 25 / 20 10 20 30 WINFIELD-KWLD 10 20 15 29 / 10 10 20 20 RUSSELL 0 15 6 20 / 10 10 50 50 GREAT BEND 4 16 9 23 / 10 10 40 20 SALINA 2 16 8 22 / 10 10 40 50 MCPHERSON 5 17 10 24 / 10 10 30 40 COFFEYVILLE 12 24 15 30 / 70 10 20 30 CHANUTE 10 20 14 27 / 60 10 20 40 IOLA 9 19 13 26 / 60 10 20 40 PARSONS-KPPF 11 22 14 29 / 70 10 20 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 708 PM CST SUN DEC 14 2008 .UPDATE... UPDATED TO INCREASE PRECIP CHANCES OVER SE KS AND TO DECREASE OVER CENTRAL AND SOUTH CENTRAL KS. PRECIP HAS INCREASED IN COVERAGE AND INTENSITY OVER SE KS. WE HAVE RECIEVED A COUPLE REPORTS OF THUNDER SLEET OVER THE LAST HOUR WITH SOME SNOW LIKELY MIXED IN. PROFILERS INDICATE THAT THE 850MB FRONT IS STILL MAKING ITS WAY THROUGH SE KS WITH SOME WARM ADVECTION ALSO INDICATED AT 700MB. IN ADDITION WATER VAPOR IMAGERY STILL SHOWING SOME WEAK UPPER ENERGY SLIDING THROUGH. THE GOOD NEWS IS THAT THIS ACTIVITY IS ON THE MOVE AND SHOULD EXIT SE KS BY AROUND 9 PM. TOOK OUT POPS FOR LOCATIONS ALONG AND WEST OF 135 AND JUST WENT WITH SOME FLURRIES THROUGH 06Z. LAWSON && .PREV DISCUSSION... /ISSUED 543 PM CST SUN DEC 14 2008/ AVIATION...Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS WILL BE SOME LIGHT PRECIP FOR THE FIRE FEW HOURS ALONG WITH SOME GUSTY NORTH WINDS. CURRENTLY HAVE SOME LIGHT SNOW...MIXING BRIEFLY WITH LIGHT SLEET...AFFECTING LOCATIONS GENERALLY ALONG AND EAST OF I-135. THIS ACTIVITY IS EXPECTED TO MOVE QUICKLY EAST AND BE OUT OF SE KS BY AROUND 03Z. CIGS ARE EXPECTED TO GRADUALLY RISE WITH ABOVE MVFR HEIGHTS EXPECTED. THE EXCEPTION WILL BE AT KCNU WHERE SOME MVFR CIGS WILL LAST THROUGH AROUND 03Z. WINDS ARE EXPECTED TO GRADUALLY DECREASE THROUGH THE NIGHT BUT WILL REMAIN OUT OF THE NORTH. LAWSON PREV DISCUSSION... /ISSUED 332 PM CST SUN DEC 14 2008/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE WIND CHILL VALUES TONIGHT AND SNOW CHANCES ACROSS CENTRAL KANSAS MONDAY NIGHT AND TUESDAY MORNING. THE NEXT CONCERN WILL BE THE FREEZING DRIZZLE AND FREEZING RAIN POTENTIAL WEDNESDAY NIGHT INTO THURSDAY MORNING. TONIGHT: LATEST WATER VAPOR LOOP WAS SHOWING THE POTENTIAL VORTICITY ANOMALY MOVING THROUGH NORTHWEST KANSAS. LATEST PROFILERS/RUC WERE ALSO SHOWING A BAROCLINIC ZONE AROUND 700MB NEAR THAT AREA. LATEST RADAR LOOP WAS ALSO SHOWING SOME NARROW BANDS OF LIGHT SNOW DEVELOPING ACROSS SOUTHWEST KANSAS EXTENDING INTO CENTRAL KANSAS. THESE INSTABILITY BANDS OF SNOW ARE ASSOCIATED WITH STEEPER LAPSE RATES ABOVE 750MB. THESE BANDS APPEARS TO FAIRLY PROGRESSIVE WHICH WILL LIMIT ANY SNOWFALL ACCUMULATION. AS A RESULT...WE HAVE LOWERED SNOWFALL ACCUMULATIONS TO ONE HALF INCH OR LESS THIS EVENING. MEANWHILE...MODELS CONTINUE TO UNDERESTIMATE THE AMOUNT OF COLD AIR POURING INTO THE AREA. AS A RESULT...WE HAVE LOWERED TEMPERATURES A COUPLE MORE DEGREES FOR OVERNIGHT LOWS. THESE LOWER TEMPERATURES COMBINED WITH GUSTY NORTH WINDS AT 10 TO 20 MPH WILL PRODUCE WIND CHILL VALUES NEAR 15 BELOW ZERO FOR A COUPLE OF HOURS OVERNIGHT IN RUSSELL AND LINCOLN COUNTIES. AFTER COLLABORATING WITH SURROUNDING FORECAST OFFICES...WE HAVE ELECTED NOT ISSUE A WIND CHILL ADVISORY. ALTHOUGH...LATER SHIFTS MAY NEED CONSIDER THIS DEPENDING IF TEMPERATURES DROP LOWER THAN THE CURRENT FORECAST. MONDAY: THE ARCTIC HIGH WILL CONTINUE TO SLIDE EAST INTO THE UPPER MIDWEST. HOWEVER...THE POLAR AIR MASS WILL NOT BUDGE WITH HIGHS STRUGGLING TO GET OUT OF THE TEENS. WIND CHILL VALUES WILL GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT-TUESDAY: ANOTHER POTENTIAL VORTICITY ANOMALY IS EXPECTED TO RIDE THROUGH NORTHWEST KANSAS AGAIN ON MONDAY NIGHT. THE GFS SEEMS TO HAVE A GOOD HANDLE ON THIS FEATURE WITH THE WAVE CURRENTLY MOVING THROUGH THE PACIFIC NORTHWEST. THIS FEATURE SHOULD PROVIDE AMPLE ISENTROPIC LIFT BETWEEN 290-295K MAINLY OVER NORTHERN KANSAS AND SOUTHERN NEBRASKA LATE MONDAY NIGHT. FORTUNATELY...IT APPEARS LIKE MOST OF THE ACTIVITY SHOULD BE OF THE FROZEN VARIETY. SNOWFALL ACCUMULATIONS SHOULD GENERALLY BE LESS THAN ONE INCH WITH THE HIGHEST AMOUNTS EXPECTED IN RUSSELL...LINCOLN AND SALINE COUNTIES. TUESDAY NIGHT-THURSDAY NIGHT: THE UPPER LEVEL FLOW IS PROGGED TO REMAIN OUT OF THE SOUTHWEST WHICH WILL PROVIDE AN UNSETTLED PATTERN DURING THIS TIMEFRAME. THE MAIN QUESTION WILL BE THE POSITION OF THE ELEVATED BAROCLINIC ZONE. RIGHT NOW WE ARE FAVORING MORE OF THE ECMWF/GFS ENSEMBLES ON THE TIMING OF THE FEATURES MOVING FROM THE ROCKIES AND NORTHERN PLAINS. THE ECMWF AND GFS ENSEMBLES ARE A LITTLE MORE AMPLIFIED WITH A WAVE MOVING THROUGH THE NORTHERN PLAINS ON LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THIS WAVE WILL JUST HELP SHOVE THE SURFACE FRONTAL BOUNDARY SOUTH THROUGH THE FORECAST AREA AND BRING A SHOT OF MODIFIED CANADIAN AIR WITH LITTLE IF ANY PRECIP. HOWEVER...THE GFS ENSEMBLES/ECMWF/UKMET ARE PICKING UP ON A STRONGER WAVE MOVING OUT OF THE ROCKIES WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS TRENDING ON PLACING THIS FRONTAL BOUNDARY FURTHER SOUTH THAN PREVIOUS RUNS. THIS WOULD FAVOR MORE OF A FREEZING RAIN EVENT IF THIS PANS OUT. THE GFS ON THE OTHER HAND...PLACES THIS BOUNDARY FURTHER NORTH BISECTING CENTRAL KANSAS. AT THIS TIME...WE ARE FAVORING THE ECMWF SOLUTION WHICH KEEPS THIS BOUNDARY FURTHER SOUTH WHILE CYCLOGENESIS GETS GOING ACROSS THE ROCKIES. THIS TIMEFRAME WILL NEED TO BE WATCHED WITH LATER RUNS. FRIDAY-SUNDAY: THE GFS/ECMWF ARE BOTH SHOWING A 1042MB HIGH DEVELOPING OVER ALASKA WHICH MAY BUILD SOUTH INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY. AS A RESULT...MORE COLD WEATHER IS ON THE HORIZON THIS WEEKEND. COX AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ARCTIC COLD FRONT WILL CONTINUE MOVING THROUGH SOUTHEAST KANSAS EARLY THIS AFTERNOON. BLUSTERY AND OCCASIONALLY STRONG NORTH TO NORTHWEST WINDS BEHIND THE FRONT WILL CONTINUE ACROSS MUCH OF THE AREA INTO THE EVENING. A NARROW AND TRANSIENT BAND OF LIFT IS EXPECTED TO DEVELOP BEHIND THE FRONT LATE THIS AFTERNOON ACROSS CENTRAL KANSAS AND SHIFT SOUTH ACROSS THE REST OF THE AREA INTO THE EARLY EVENING. THIS MAY RESULT IN A BRIEF PERIOD OF LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE. MVFR CIGS WILL PREVAIL ACROSS THE AREA FOR MUCH OF THE FORECAST VALID PERIOD. KED && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 8 19 13 26 / 10 10 20 20 HUTCHINSON 7 18 11 24 / 10 10 30 20 NEWTON 7 17 13 24 / 10 10 30 30 ELDORADO 8 18 13 25 / 20 10 20 30 WINFIELD-KWLD 10 20 15 29 / 10 10 20 20 RUSSELL 0 15 6 20 / 10 10 50 50 GREAT BEND 4 16 9 23 / 10 10 40 20 SALINA 4 16 8 22 / 10 10 40 50 MCPHERSON 6 17 10 24 / 10 10 30 40 COFFEYVILLE 12 24 15 30 / 70 10 20 30 CHANUTE 10 20 14 27 / 60 10 20 40 IOLA 9 19 13 26 / 60 10 20 40 PARSONS-KPPF 11 22 14 29 / 70 10 20 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 543 PM CST SUN DEC 14 2008 .AVIATION...Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS WILL BE SOME LIGHT PRECIP FOR THE FIRE FEW HOURS ALONG WITH SOME GUSTY NORTH WINDS. CURRENTLY HAVE SOME LIGHT SNOW...MIXING BRIEFLY WITH LIGHT SLEET...AFFECTING LOCATIONS GENERALLY ALONG AND EAST OF I-135. THIS ACTIVITY IS EXPECTED TO MOVE QUICKLY EAST AND BE OUT OF SE KS BY AROUND 03Z. CIGS ARE EXPECTED TO GRADUALLY RISE WITH ABOVE MVFR HEIGHTS EXPECTED. THE EXCEPTION WILL BE AT KCNU WHERE SOME MVFR CIGS WILL LAST THROUGH AROUND 03Z. WINDS ARE EXPECTED TO GRADUALLY DECREASE THROUGH THE NIGHT BUT WILL REMAIN OUT OF THE NORTH. LAWSON && .PREV DISCUSSION... /ISSUED 332 PM CST SUN DEC 14 2008/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE WIND CHILL VALUES TONIGHT AND SNOW CHANCES ACROSS CENTRAL KANSAS MONDAY NIGHT AND TUESDAY MORNING. THE NEXT CONCERN WILL BE THE FREEZING DRIZZLE AND FREEZING RAIN POTENTIAL WEDNESDAY NIGHT INTO THURSDAY MORNING. TONIGHT: LATEST WATER VAPOR LOOP WAS SHOWING THE POTENTIAL VORTICITY ANOMALY MOVING THROUGH NORTHWEST KANSAS. LATEST PROFILERS/RUC WERE ALSO SHOWING A BAROCLINIC ZONE AROUND 700MB NEAR THAT AREA. LATEST RADAR LOOP WAS ALSO SHOWING SOME NARROW BANDS OF LIGHT SNOW DEVELOPING ACROSS SOUTHWEST KANSAS EXTENDING INTO CENTRAL KANSAS. THESE INSTABILITY BANDS OF SNOW ARE ASSOCIATED WITH STEEPER LAPSE RATES ABOVE 750MB. THESE BANDS APPEARS TO FAIRLY PROGRESSIVE WHICH WILL LIMIT ANY SNOWFALL ACCUMULATION. AS A RESULT...WE HAVE LOWERED SNOWFALL ACCUMULATIONS TO ONE HALF INCH OR LESS THIS EVENING. MEANWHILE...MODELS CONTINUE TO UNDERESTIMATE THE AMOUNT OF COLD AIR POURING INTO THE AREA. AS A RESULT...WE HAVE LOWERED TEMPERATURES A COUPLE MORE DEGREES FOR OVERNIGHT LOWS. THESE LOWER TEMPERATURES COMBINED WITH GUSTY NORTH WINDS AT 10 TO 20 MPH WILL PRODUCE WIND CHILL VALUES NEAR 15 BELOW ZERO FOR A COUPLE OF HOURS OVERNIGHT IN RUSSELL AND LINCOLN COUNTIES. AFTER COLLABORATING WITH SURROUNDING FORECAST OFFICES...WE HAVE ELECTED NOT ISSUE A WIND CHILL ADVISORY. ALTHOUGH...LATER SHIFTS MAY NEED CONSIDER THIS DEPENDING IF TEMPERATURES DROP LOWER THAN THE CURRENT FORECAST. MONDAY: THE ARCTIC HIGH WILL CONTINUE TO SLIDE EAST INTO THE UPPER MIDWEST. HOWEVER...THE POLAR AIR MASS WILL NOT BUDGE WITH HIGHS STRUGGLING TO GET OUT OF THE TEENS. WIND CHILL VALUES WILL GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT-TUESDAY: ANOTHER POTENTIAL VORTICITY ANOMALY IS EXPECTED TO RIDE THROUGH NORTHWEST KANSAS AGAIN ON MONDAY NIGHT. THE GFS SEEMS TO HAVE A GOOD HANDLE ON THIS FEATURE WITH THE WAVE CURRENTLY MOVING THROUGH THE PACIFIC NORTHWEST. THIS FEATURE SHOULD PROVIDE AMPLE ISENTROPIC LIFT BETWEEN 290-295K MAINLY OVER NORTHERN KANSAS AND SOUTHERN NEBRASKA LATE MONDAY NIGHT. FORTUNATELY...IT APPEARS LIKE MOST OF THE ACTIVITY SHOULD BE OF THE FROZEN VARIETY. SNOWFALL ACCUMULATIONS SHOULD GENERALLY BE LESS THAN ONE INCH WITH THE HIGHEST AMOUNTS EXPECTED IN RUSSELL...LINCOLN AND SALINE COUNTIES. TUESDAY NIGHT-THURSDAY NIGHT: THE UPPER LEVEL FLOW IS PROGGED TO REMAIN OUT OF THE SOUTHWEST WHICH WILL PROVIDE AN UNSETTLED PATTERN DURING THIS TIMEFRAME. THE MAIN QUESTION WILL BE THE POSITION OF THE ELEVATED BAROCLINIC ZONE. RIGHT NOW WE ARE FAVORING MORE OF THE ECMWF/GFS ENSEMBLES ON THE TIMING OF THE FEATURES MOVING FROM THE ROCKIES AND NORTHERN PLAINS. THE ECMWF AND GFS ENSEMBLES ARE A LITTLE MORE AMPLIFIED WITH A WAVE MOVING THROUGH THE NORTHERN PLAINS ON LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THIS WAVE WILL JUST HELP SHOVE THE SURFACE FRONTAL BOUNDARY SOUTH THROUGH THE FORECAST AREA AND BRING A SHOT OF MODIFIED CANADIAN AIR WITH LITTLE IF ANY PRECIP. HOWEVER...THE GFS ENSEMBLES/ECMWF/UKMET ARE PICKING UP ON A STRONGER WAVE MOVING OUT OF THE ROCKIES WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS TRENDING ON PLACING THIS FRONTAL BOUNDARY FURTHER SOUTH THAN PREVIOUS RUNS. THIS WOULD FAVOR MORE OF A FREEZING RAIN EVENT IF THIS PANS OUT. THE GFS ON THE OTHER HAND...PLACES THIS BOUNDARY FURTHER NORTH BISECTING CENTRAL KANSAS. AT THIS TIME...WE ARE FAVORING THE ECMWF SOLUTION WHICH KEEPS THIS BOUNDARY FURTHER SOUTH WHILE CYCLOGENESIS GETS GOING ACROSS THE ROCKIES. THIS TIMEFRAME WILL NEED TO BE WATCHED WITH LATER RUNS. FRIDAY-SUNDAY: THE GFS/ECMWF ARE BOTH SHOWING A 1042MB HIGH DEVELOPING OVER ALASKA WHICH MAY BUILD SOUTH INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY. AS A RESULT...MORE COLD WEATHER IS ON THE HORIZON THIS WEEKEND. COX AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ARCTIC COLD FRONT WILL CONTINUE MOVING THROUGH SOUTHEAST KANSAS EARLY THIS AFTERNOON. BLUSTERY AND OCCASIONALLY STRONG NORTH TO NORTHWEST WINDS BEHIND THE FRONT WILL CONTINUE ACROSS MUCH OF THE AREA INTO THE EVENING. A NARROW AND TRANSIENT BAND OF LIFT IS EXPECTED TO DEVELOP BEHIND THE FRONT LATE THIS AFTERNOON ACROSS CENTRAL KANSAS AND SHIFT SOUTH ACROSS THE REST OF THE AREA INTO THE EARLY EVENING. THIS MAY RESULT IN A BRIEF PERIOD OF LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE. MVFR CIGS WILL PREVAIL ACROSS THE AREA FOR MUCH OF THE FORECAST VALID PERIOD. KED && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 8 19 13 26 / 40 10 20 20 HUTCHINSON 7 18 11 24 / 40 10 30 20 NEWTON 7 17 13 24 / 40 10 30 30 ELDORADO 8 18 13 25 / 40 10 20 30 WINFIELD-KWLD 10 20 15 29 / 30 10 20 20 RUSSELL 0 15 6 20 / 20 10 50 50 GREAT BEND 4 16 9 23 / 30 10 40 20 SALINA 4 16 8 22 / 30 10 40 50 MCPHERSON 6 17 10 24 / 40 10 30 40 COFFEYVILLE 12 24 15 30 / 40 10 20 30 CHANUTE 10 20 14 27 / 40 10 20 40 IOLA 9 19 13 26 / 40 10 20 40 PARSONS-KPPF 11 22 14 29 / 40 10 20 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE WICHITA KS 332 PM CST SUN DEC 14 2008 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE WIND CHILL VALUES TONIGHT AND SNOW CHANCES ACROSS CENTRAL KANSAS MONDAY NIGHT AND TUESDAY MORNING. THE NEXT CONCERN WILL BE THE FREEZING DRIZZLE AND FREEZING RAIN POTENTIAL WEDNESDAY NIGHT INTO THURSDAY MORNING. TONIGHT: LATEST WATER VAPOR LOOP WAS SHOWING THE POTENTIAL VORTICITY ANOMALY MOVING THROUGH NORTHWEST KANSAS. LATEST PROFILERS/RUC WERE ALSO SHOWING A BAROCLINIC ZONE AROUND 700MB NEAR THAT AREA. LATEST RADAR LOOP WAS ALSO SHOWING SOME NARROW BANDS OF LIGHT SNOW DEVELOPING ACROSS SOUTHWEST KANSAS EXTENDING INTO CENTRAL KANSAS. THESE INSTABILITY BANDS OF SNOW ARE ASSOCIATED WITH STEEPER LAPSE RATES ABOVE 750MB. THESE BANDS APPEARS TO FAIRLY PROGRESSIVE WHICH WILL LIMIT ANY SNOWFALL ACCUMULATION. AS A RESULT...WE HAVE LOWERED SNOWFALL ACCUMULATIONS TO ONE HALF INCH OR LESS THIS EVENING. MEANWHILE...MODELS CONTINUE TO UNDERESTIMATE THE AMOUNT OF COLD AIR POURING INTO THE AREA. AS A RESULT...WE HAVE LOWERED TEMPERATURES A COUPLE MORE DEGREES FOR OVERNIGHT LOWS. THESE LOWER TEMPERATURES COMBINED WITH GUSTY NORTH WINDS AT 10 TO 20 MPH WILL PRODUCE WIND CHILL VALUES NEAR 15 BELOW ZERO FOR A COUPLE OF HOURS OVERNIGHT IN RUSSELL AND LINCOLN COUNTIES. AFTER COLLABORATING WITH SURROUNDING FORECAST OFFICES...WE HAVE ELECTED NOT ISSUE A WIND CHILL ADVISORY. ALTHOUGH...LATER SHIFTS MAY NEED CONSIDER THIS DEPENDING IF TEMPERATURES DROP LOWER THAN THE CURRENT FORECAST. MONDAY: THE ARCTIC HIGH WILL CONTINUE TO SLIDE EAST INTO THE UPPER MIDWEST. HOWEVER...THE POLAR AIR MASS WILL NOT BUDGE WITH HIGHS STRUGGLING TO GET OUT OF THE TEENS. WIND CHILL VALUES WILL GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT-TUESDAY: ANOTHER POTENTIAL VORTICITY ANOMALY IS EXPECTED TO RIDE THROUGH NORTHWEST KANSAS AGAIN ON MONDAY NIGHT. THE GFS SEEMS TO HAVE A GOOD HANDLE ON THIS FEATURE WITH THE WAVE CURRENTLY MOVING THROUGH THE PACIFIC NORTHWEST. THIS FEATURE SHOULD PROVIDE AMPLE ISENTROPIC LIFT BETWEEN 290-295K MAINLY OVER NORTHERN KANSAS AND SOUTHERN NEBRASKA LATE MONDAY NIGHT. FORTUNATELY...IT APPEARS LIKE MOST OF THE ACTIVITY SHOULD BE OF THE FROZEN VARIETY. SNOWFALL ACCUMULATIONS SHOULD GENERALLY BE LESS THAN ONE INCH WITH THE HIGHEST AMOUNTS EXPECTED IN RUSSELL...LINCOLN AND SALINE COUNTIES. TUESDAY NIGHT-THURSDAY NIGHT: THE UPPER LEVEL FLOW IS PROGGED TO REMAIN OUT OF THE SOUTHWEST WHICH WILL PROVIDE AN UNSETTLED PATTERN DURING THIS TIMEFRAME. THE MAIN QUESTION WILL BE THE POSITION OF THE ELEVATED BAROCLINIC ZONE. RIGHT NOW WE ARE FAVORING MORE OF THE ECMWF/GFS ENSEMBLES ON THE TIMING OF THE FEATURES MOVING FROM THE ROCKIES AND NORTHERN PLAINS. THE ECMWF AND GFS ENSEMBLES ARE A LITTLE MORE AMPLIFIED WITH A WAVE MOVING THROUGH THE NORTHERN PLAINS ON LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THIS WAVE WILL JUST HELP SHOVE THE SURFACE FRONTAL BOUNDARY SOUTH THROUGH THE FORECAST AREA AND BRING A SHOT OF MODIFIED CANADIAN AIR WITH LITTLE IF ANY PRECIP. HOWEVER...THE GFS ENSEMBLES/ECMWF/UKMET ARE PICKING UP ON A STRONGER WAVE MOVING OUT OF THE ROCKIES WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS TRENDING ON PLACING THIS FRONTAL BOUNDARY FURTHER SOUTH THAN PREVIOUS RUNS. THIS WOULD FAVOR MORE OF A FREEZING RAIN EVENT IF THIS PANS OUT. THE GFS ON THE OTHER HAND...PLACES THIS BOUNDARY FURTHER NORTH BISECTING CENTRAL KANSAS. AT THIS TIME...WE ARE FAVORING THE ECMWF SOLUTION WHICH KEEPS THIS BOUNDARY FURTHER SOUTH WHILE CYCLOGENESIS GETS GOING ACROSS THE ROCKIES. THIS TIMEFRAME WILL NEED TO BE WATCHED WITH LATER RUNS. FRIDAY-SUNDAY: THE GFS/ECMWF ARE BOTH SHOWING A 1042MB HIGH DEVELOPING OVER ALASKA WHICH MAY BUILD SOUTH INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY. AS A RESULT...MORE COLD WEATHER IS ON THE HORIZON THIS WEEKEND. COX && .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ARCTIC COLD FRONT WILL CONTINUE MOVING THROUGH SOUTHEAST KANSAS EARLY THIS AFTERNOON. BLUSTERY AND OCCASIONALLY STRONG NORTH TO NORTHWEST WINDS BEHIND THE FRONT WILL CONTINUE ACROSS MUCH OF THE AREA INTO THE EVENING. A NARROW AND TRANSIENT BAND OF LIFT IS EXPECTED TO DEVELOP BEHIND THE FRONT LATE THIS AFTERNOON ACROSS CENTRAL KANSAS AND SHIFT SOUTH ACROSS THE REST OF THE AREA INTO THE EARLY EVENING. THIS MAY RESULT IN A BRIEF PERIOD OF LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE. MVFR CIGS WILL PREVAIL ACROSS THE AREA FOR MUCH OF THE FORECAST VALID PERIOD. KED .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 8 19 13 26 / 40 10 20 20 HUTCHINSON 7 18 11 24 / 40 10 30 20 NEWTON 7 17 13 24 / 40 10 30 30 ELDORADO 8 18 13 25 / 40 10 20 30 WINFIELD-KWLD 10 20 15 29 / 30 10 20 20 RUSSELL 0 15 6 20 / 20 10 50 50 GREAT BEND 4 16 9 23 / 30 10 40 20 SALINA 4 16 8 22 / 30 10 40 50 MCPHERSON 6 17 10 24 / 40 10 30 40 COFFEYVILLE 12 24 15 30 / 40 10 20 30 CHANUTE 10 20 14 27 / 40 10 20 40 IOLA 9 19 13 26 / 40 10 20 40 PARSONS-KPPF 11 22 14 29 / 40 10 20 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 420 AM MST SUN DEC 14 2008 .PREV DISCUSSION... /ISSUED 225 AM MST SUN DEC 14 2008/ .DISCUSSION... 224 AM MST SUN DEC 14 2008 04Z WATER VAPOR IMAGERY INDICATED POSITIVELY TILTED TROUGH SLIDING EAST ACROSS WYOMING...WITH RUC TROP ANALYSIS INDICATING ANOTHER SHORTWAVE TROUGH MOVING INTO ARIZONA. AT THE SFC...ARCTIC COLD FRONT MOVING RAPIDLY ACROSS THE NORTHERN HIGH PLAINS...WITH LEADING EDGE ALREADY THROUGH YUMA AROUND 4Z. LARGE AREA OF SUB ZERO TEMPS OBSERVED ACROSS WYOMING AND NORTHWEST SOUTH DAKOTA. BOTH THE NAM AND GFS OVERALL INITIALIZED DECENT ACROSS THE AREA...ALTHOUGH THERE WERE VARIOUS ERRORS IN THE H7 AND H85 THERMAL FIELD WITH RESPECT TO THE FRONT. PRIMARY FORECAST CONCERN WILL BE WINDS...TEMPS AND SNOWFALL CHANCES BEHIND TODAYS ARCTIC FRONT...FOLLOWED BY SNOW CHANCES MONDAY AND TUESDAY. TODAY-TONIGHT...MODELS STILL SEEM DIVIDED ON PRECIP CHANCES TODAY AND ARE DIVIDED BETWEEN THE FAIRLY DRY NAM AND WETTER GFS. FORCING AND INSTABILITY PARAMETERS ALSO REMAIN SIMILAR TO LAST NIGHTS RUN WITH PRIMARY FORCING FOR ASCENT BEING STRONG BAND OF FRONTOGENESIS MAINLY BETWEEN H7-H6. H5-H3 DIV Q FIELDS SUGGEST SOME UPPER LEVEL FORCING FOR ASCENT AS 145KT JET STREAK MOVES INTO SW KANSAS. IT APPEARS THE PROBLEM WITH THIS SYSTEM WILL BE WHETHER OR NOT FORCING WILL BE SUFFICENT TO SATURATE LAYER ABOVE THE FRONTAL ZONE WHICH WOULD ALLOW AVAILABLE CONDITIONAL INSTABILITY TO BE RELEASED. IF FORCING IS NOT SUFFICENT (AS NAM SUGGESTS) PRECIP PROCESSES WILL LIKELY BE VERY SHALLOW AND RESULTING PRECIP MORE OF THE FLURRY VARIETY. IF INSTABILITY IS REALIZED...WOULD EXPECT A DECENT BAND OF SNOW TO DEVELOP ALONG AXIS OF FRONTOGENESIS. THE FAST MOVEMENT OF THE FRONTAL ZONE...BRIEF WINDOW OF DEEP LAYER ASCENT...AND TIME IT WILL TAKE TO SATURATE LEVEL IMMEDIATELY ABOVE FRONTAL ZONE WILL LIKELY LIMIT ANY ACCUMULATIONS EVEN UNDER BEST CIRCUMSTANCES. WELL CONTINUE TO MONITOR TRENDS BEFORE ISSUING FORECAST BUT FOR THE TIME BEING PLAN TO LIMIT HIGHER POPS/QPF TO WESTERN ZONES AS A COMPROMISE BETWEEN AVAILABLE MODEL SOLUTIONS. SUBSIDENCE SHOULD OVERSPREAD THE ENTIRE AREA BY 00Z...BRINGING AN END TO ANY PRECIP CHANCES. 06Z NAM NOW TRENDING TOWARDS THE GFS...WITH LATEST PRECIP FIELDS LINING UP WELL WITH EXPECTED FRONTOGENETICAL FORCING. PLAN ON UPPING POPS TO THE 40-60 PERCENT RANGE WITH HIGHEST POPS AND AMOUNTS ACROSS YUMA COUNTY. AMOUNTS IN THE 1-2 INCH RANGE LOOK REASONABLE FOR NOW. OTHER CONCERN FOR THE PERIOD WILL BE WINDS AND WIND CHILLS AS COLD AIR MOVES INTO THE AREA. CURRENT WIND CHILLS ALREADY NEAR -10 AT YMA...AND WITH STRONG COLD AIR ADVECTION IN PLACE DOUBT THAT CONDITIONS WILL IMPROVE MUCH THROUGH THE DAY. WILL LIKELY SEE WIND CHILL ADVISORY CRITERIA CONTINUING THROUGH THE EARLY EVENING UNTIL WINDS DECOUPLE...BUT WITH STRENGTH OF THE COLD AIR THINK THERE IS POTENTIAL FOR RAPID DECOUPLING SO OVERALL CONFIDENCE IN WIND ADVISORY CRITERIA TONIGHT IS LOW. WITH WIND CHILLS BELOW AT -15F AND SOME BLOWING AND DRIFTING SNOW WILL ISSUE A SMALL WINTER WX ADVISORY FOR YUMA COUNTY. WINDS WILL DEFINITELY BE STRONG AROUND 12Z...WITH SEVERAL SPOTS LIKELY AT OR JUST BELOW ADVISORY CRITERIA. BASED ON PATTERN THINK THIS WILL BE CONFINED TO A BRIEF PERIOD AS STRONGEST PRESSURE RISES MOVE THROUGH THE AREA. AT THIS TIME WILL NOT ISSUE ANY KIND OF HIGHLIGHT...BUT WILL MONITOR THE WINDS AND MAKE A FINAL CALL BY SUNRISE. MONDAY...SHORT WAVE RIDGING WILL BE IN PLACE ACROSS THE AREA THROUGH THE DAY...WITH MAIN CONCERN BEING TEMPS. WITH STRONG WESTERLY JET OVERHEAD...AM A LITTLE CONCERNED THAT TEMPS WILL REALLY STRUGGLE TO WARM MUCH...ESPECIALLY GIVEN THE OBSERVED MAGNITUDE OF THE COLD AIR UPSTREAM. MONDAY NIGHT-WEDNESDAY MORNING...WHILE THE SHORT RANGE MODELS WERE IN AGREEMENT LAST NIGHT WITH THIS PERIOD...NAM AND GFS HAVE STARTED TO DIVERGE WITH RESPECT TO THE HANDLING OF THE NEXT SYSTEM. NAM APPEARS TO BE THE OUTLIER AT THIS TIME WITH SLOWER...MORE AGGRESSIVE SOLUTION AND FOR THE TIME BEING WILL TREND FORECAST TOWARDS THE GFS WHICH IS SUPPORTED BY THE CANADIAN...UKMET AND SREF MEAN. STRONG WAA WILL DEVELOP ACROSS THE CWA H3 JET AXIS SHIFTS TO THE NORTH. DIFFERENTIAL TEMP ADVECTION APPEARS SUFFICENT TO RESULT IN SOME INSTABILITY OVERNIGHT...BUT AM CONCERNED ABOUT QUALITY OF MOISTURE RETURN ESPECIALLY TO THE NORTH OF SUCH A STRONG COLD FRONT. CONCERNS ASIDE...ENOUGH CONSENSUS IN THE MODELS TO UP CHANCES IN THE EASTERN CWA. ACTUALLY MAY HAVE SOME PRECIP TYPE CONCERNS AS GFS SUGGESTING A WARM LAYER DEVELOPS ACRS THE SOUTHWEST CWA TUESDAY MORNING. COULD SEE SNOW TRANSITION TO -FZDZ BEFORE ENDING BUT CURRENT DATA SUGGESTS PRECIP WILL END BEFORE THIS LAYER DEVELOPS. JET STREAK WILL CONTINUE TO LINGER TO THE NORTH OF THE AREA WITH CWA COMING UNDER THE INFLUENCE OF ENTRANCE REGION OVERNIGHT. GFS INDICATING A FAIRLY STRONG RESPONSE TO THIS FEATURE...WITH A DEEP FRONTOGENETICAL CIRCULATION (H8-H6) DEVELOPING ACROSS THE CWA. WILL ADD SOME LOW POPS TO THE PERIOD FOR NOW...BUT WITH ALL THE UNCERTAINTY BEFORE THIS POINT DO NOT WANT TO PLACE TO MUCH EMPHASIS ON THIS ONE MODEL RUN. WED-SAT...NO CHANGES PLANNED AT THIS TIME. JRM && .AVIATION... 420 AM MST SUN DEC 14 2008 FOR THE 12Z TAFS...MVFR CIGS EXPECTED THROUGH 23Z OR SO IN STRATUS AT BOTH KGLD AND KMCK. AROUND OR SHORTLY AFTER 23Z CIGS WILL IMPROVE TO VFR WITH SKC CONDITIONS EXPECTED. A BAND OF LIGHT TO POSSIBLY MODERATE SNOW IS EXPECTED SHORTLY AFTER 15Z AT BOTH SITES CONTINUING THROUGH 20-21Z WITH VIS BEING REDUCED TO A FEW MILES...POSSIBLY CREATING IFR CONDITIONS. WIND GUSTS OF 35KTS OR SO WILL CONTINUE THROUGH 20Z BEFORE SLOWLY DECREASING BELOW 15KTS BY 23Z AT BOTH SITES AS WELL. 07 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...WIND CHILL ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR KSZ001-002. NE...WIND CHILL ADVISORY UNTIL 1 PM MST /2 PM CST/ THIS AFTERNOON FOR NEZ079>081. CO...WIND CHILL ADVISORY UNTIL 1 PM MST THIS AFTERNOON FOR COZ091. WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ090. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 225 AM MST SUN DEC 14 2008 .DISCUSSION... 224 AM MST SUN DEC 14 2008 04Z WATER VAPOR IMAGERY INDICATED POSITIVELY TILTED TROUGH SLIDING EAST ACROSS WYOMING...WITH RUC TROP ANALYSIS INDICATING ANOTHER SHORTWAVE TROUGH MOVING INTO ARIZONA. AT THE SFC...ARCTIC COLD FRONT MOVING RAPIDLY ACROSS THE NORTHERN HIGH PLAINS...WITH LEADING EDGE ALREADY THROUGH YUMA AROUND 4Z. LARGE AREA OF SUB ZERO TEMPS OBSERVED ACROSS WYOMING AND NORTHWEST SOUTH DAKOTA. BOTH THE NAM AND GFS OVERALL INITIALIZED DECENT ACROSS THE AREA...ALTHOUGH THERE WERE VARIOUS ERRORS IN THE H7 AND H85 THERMAL FIELD WITH RESPECT TO THE FRONT. PRIMARY FORECAST CONCERN WILL BE WINDS...TEMPS AND SNOWFALL CHANCES BEHIND TODAYS ARCTIC FRONT...FOLLOWED BY SNOW CHANCES MONDAY AND TUESDAY. TODAY-TONIGHT...MODELS STILL SEEM DIVIDED ON PRECIP CHANCES TODAY AND ARE DIVIDED BETWEEN THE FAIRLY DRY NAM AND WETTER GFS. FORCING AND INSTABILITY PARAMETERS ALSO REMAIN SIMILAR TO LAST NIGHTS RUN WITH PRIMARY FORCING FOR ASCENT BEING STRONG BAND OF FRONTOGENESIS MAINLY BETWEEN H7-H6. H5-H3 DIV Q FIELDS SUGGEST SOME UPPER LEVEL FORCING FOR ASCENT AS 145KT JET STREAK MOVES INTO SW KANSAS. IT APPEARS THE PROBLEM WITH THIS SYSTEM WILL BE WHETHER OR NOT FORCING WILL BE SUFFICENT TO SATURATE LAYER ABOVE THE FRONTAL ZONE WHICH WOULD ALLOW AVAILABLE CONDITIONAL INSTABILITY TO BE RELEASED. IF FORCING IS NOT SUFFICENT (AS NAM SUGGESTS) PRECIP PROCESSES WILL LIKELY BE VERY SHALLOW AND RESULTING PRECIP MORE OF THE FLURRY VARIETY. IF INSTABILITY IS REALIZED...WOULD EXPECT A DECENT BAND OF SNOW TO DEVELOP ALONG AXIS OF FRONTOGENESIS. THE FAST MOVEMENT OF THE FRONTAL ZONE...BRIEF WINDOW OF DEEP LAYER ASCENT...AND TIME IT WILL TAKE TO SATURATE LEVEL IMMEDIATELY ABOVE FRONTAL ZONE WILL LIKELY LIMIT ANY ACCUMULATIONS EVEN UNDER BEST CIRCUMSTANCES. WELL CONTINUE TO MONITOR TRENDS BEFORE ISSUING FORECAST BUT FOR THE TIME BEING PLAN TO LIMIT HIGHER POPS/QPF TO WESTERN ZONES AS A COMPROMISE BETWEEN AVAILABLE MODEL SOLUTIONS. SUBSIDENCE SHOULD OVERSPREAD THE ENTIRE AREA BY 00Z...BRINGING AN END TO ANY PRECIP CHANCES. 06Z NAM NOW TRENDING TOWARDS THE GFS...WITH LATEST PRECIP FIELDS LINING UP WELL WITH EXPECTED FRONTOGENETICAL FORCING. PLAN ON UPPING POPS TO THE 40-60 PERCENT RANGE WITH HIGHEST POPS AND AMOUNTS ACROSS YUMA COUNTY. AMOUNTS IN THE 1-2 INCH RANGE LOOK REASONABLE FOR NOW. OTHER CONCERN FOR THE PERIOD WILL BE WINDS AND WIND CHILLS AS COLD AIR MOVES INTO THE AREA. CURRENT WIND CHILLS ALREADY NEAR -10 AT YMA...AND WITH STRONG COLD AIR ADVECTION IN PLACE DOUBT THAT CONDITIONS WILL IMPROVE MUCH THROUGH THE DAY. WILL LIKELY SEE WIND CHILL ADVISORY CRITERIA CONTINUING THROUGH THE EARLY EVENING UNTIL WINDS DECOUPLE...BUT WITH STRENGTH OF THE COLD AIR THINK THERE IS POTENTIAL FOR RAPID DECOUPLING SO OVERALL CONFIDENCE IN WIND ADVISORY CRITERIA TONIGHT IS LOW. WITH WIND CHILLS BELOW AT -15F AND SOME BLOWING AND DRIFTING SNOW WILL ISSUE A SMALL WINTER WX ADVISORY FOR YUMA COUNTY. WINDS WILL DEFINITELY BE STRONG AROUND 12Z...WITH SEVERAL SPOTS LIKELY AT OR JUST BELOW ADVISORY CRITERIA. BASED ON PATTERN THINK THIS WILL BE CONFINED TO A BRIEF PERIOD AS STRONGEST PRESSURE RISES MOVE THROUGH THE AREA. AT THIS TIME WILL NOT ISSUE ANY KIND OF HIGHLIGHT...BUT WILL MONITOR THE WINDS AND MAKE A FINAL CALL BY SUNRISE. MONDAY...SHORT WAVE RIDGING WILL BE IN PLACE ACROSS THE AREA THROUGH THE DAY...WITH MAIN CONCERN BEING TEMPS. WITH STRONG WESTERLY JET OVERHEAD...AM A LITTLE CONCERNED THAT TEMPS WILL REALLY STRUGGLE TO WARM MUCH...ESPECIALLY GIVEN THE OBSERVED MAGNITUDE OF THE COLD AIR UPSTREAM. MONDAY NIGHT-WEDNESDAY MORNING...WHILE THE SHORT RANGE MODELS WERE IN AGREEMENT LAST NIGHT WITH THIS PERIOD...NAM AND GFS HAVE STARTED TO DIVERGE WITH RESPECT TO THE HANDLING OF THE NEXT SYSTEM. NAM APPEARS TO BE THE OUTLIER AT THIS TIME WITH SLOWER...MORE AGGRESSIVE SOLUTION AND FOR THE TIME BEING WILL TREND FORECAST TOWARDS THE GFS WHICH IS SUPPORTED BY THE CANADIAN...UKMET AND SREF MEAN. STRONG WAA WILL DEVELOP ACROSS THE CWA H3 JET AXIS SHIFTS TO THE NORTH. DIFFERENTIAL TEMP ADVECTION APPEARS SUFFICENT TO RESULT IN SOME INSTABILITY OVERNIGHT...BUT AM CONCERNED ABOUT QUALITY OF MOISTURE RETURN ESPECIALLY TO THE NORTH OF SUCH A STRONG COLD FRONT. CONCERNS ASIDE...ENOUGH CONSENSUS IN THE MODELS TO UP CHANCES IN THE EASTERN CWA. ACTUALLY MAY HAVE SOME PRECIP TYPE CONCERNS AS GFS SUGGESTING A WARM LAYER DEVELOPS ACRS THE SOUTHWEST CWA TUESDAY MORNING. COULD SEE SNOW TRANSITION TO -FZDZ BEFORE ENDING BUT CURRENT DATA SUGGESTS PRECIP WILL END BEFORE THIS LAYER DEVELOPS. JET STREAK WILL CONTINUE TO LINGER TO THE NORTH OF THE AREA WITH CWA COMING UNDER THE INFLUENCE OF ENTRANCE REGION OVERNIGHT. GFS INDICATING A FAIRLY STRONG RESPONSE TO THIS FEATURE...WITH A DEEP FRONTOGENETICAL CIRCULATION (H8-H6) DEVELOPING ACROSS THE CWA. WILL ADD SOME LOW POPS TO THE PERIOD FOR NOW...BUT WITH ALL THE UNCERTAINTY BEFORE THIS POINT DO NOT WANT TO PLACE TO MUCH EMPHASIS ON THIS ONE MODEL RUN. WED-SAT...NO CHANGES PLANNED AT THIS TIME. JRM && .AVIATION...FOR THE 06Z TAFS...COLD FRONT IS MOVING QUICKLY ACROSS THE HIGH PLAINS. EXPECT FRONTAL PASSAGE EARLY IN THE FORECAST PERIOD WITH DETERIORATING CONDITIONS THROUGH THE NIGHT. HAVE INDICATED MVFR CONDITIONS AT KGLD/KMCK WITH LIGHT SNOW AROUND 10Z-12Z...BUT WOULD NOT BE SURPRISED TO SEE CONDITIONS BRIEFLY DROP TO IFR. NORTH WINDS WITH FRONT WILL BE NORTH AT 20-35 KNOTS WITH GUSTS TO 40 KNOTS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ090. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 259 PM CST SAT DEC 13 2008 .DISCUSSION... DAYS 1-2... MAIN QUESTIONS WILL BE WHAT HAPPENS WITH THE FRONT COMING DOWN, HOW FAST TEMPS FALL, WHAT THE WINDS WILL DO, AND IF WE GET ANY PRECIP. 00Z UPPER AIR OBS CONTINUE TO SHOW A LARGE TROUGH DIGGING INTO THE WESTERN CONUS WITH 200-230 M HEIGHT FALLS AT 500MB. THE SFC LOW HAS BEEN DEEPENING ACROSS WY THIS MORNING, WITH GOOD SOUTHERLY WINDS CONTINUING OVER WESTERN KS. GRADIENT HAS WEAKENED IN ALL BUT THE SOUTHEASTERN COUNTIES, SO WILL KEEP THE WIND ADVISORY FOR THERE GOING UNTIL 00Z BUT HAVE CANCELED THE WESTERN COUNTIES. WARM POCKET AT 850MB CONTINUES ACROSS THE WESTERN PLAINS WITH TEMPS AT 12Z AROUND 10 C. HOWEVER, THE COLD AIR IS JUST TO OUR NORTH, WITH THE ARCTIC FRONT ALREADY DOWN INTO SD AND WY AS OF 20Z. THE FRONT SHOULD CONTINUE TO PLUNGE SOUTH TONIGHT, MOVING INTO OUR FAR NORTHERN COUNTIES AROUND 12Z. THINK THAT SOUTHERLY FLOW AHEAD OF THE FRONT SHOULD KEEP READINGS TONIGHT FAIRLY MILD, SO CONTINUED WITH LOWS IN THE 30S AND 40S. THE FRONT SHOULD PUSH THROUGH FAIRLY QUICKLY TOMORROW MORNING, PASSING THROUGH THE MAJORITY OF OUR COUNTIES BY 18Z. GOING FORECAST HAD FALLING TEMPS AFTER THE FRONT COMES THROUGH, AND THIS CONTINUES TO SEEM REASONABLE. NORTHERLY WINDS WILL ALSO BECOME FAIRLY STRONG BEHIND THE FRONT, ALTHOUGH WITH THE 850MB TROUGH AXIS OVERHEAD THERE IS SOME QUESTION ON HOW STRONG WINDS WILL GET. NAM AND GFS BOTH HAVE ONLY 20 TO 25 KTS OFF THE DECK DURING THE PEAK PERIOD OF MOMENTUM TRANSFER IN THE AFTERNOON. THE NORMALLY FAIRLY WINDY RUC ALSO KEEPS THE HIGHEST WINDS TO OUR NORTHEAST. THINK THERE IS A CHANCE FOR SOME BRIEF ADVISORY LEVEL WINDS RIGHT BEHIND THE FRONT, BUT WILL HOLD OFF ON HEADLINES FOR NOW. THE UPPER TROUGH DIGGING INTO THE NORTHERN AND CENTRAL PLAINS SHOULD ALSO HELP BRING SOME PRECIP TO THE REGION. HOWEVER, IT LOOKS LIKE MOST OF THE LIFT WILL BE CONCENTRATED TO OUR NORTH, AND THERE WILL NOT BE MUCH MOISTURE TO WORK WITH. STILL, THERE IS A DECENT MID LEVEL BAROCLINIC ZONE HEADED DOWN INTO THE CWA BY SUNDAY AFTERNOON AND EVENING, AND MODEL SOUNDINGS SHOW A GOOD SATURATED LAYER FROM 600MB DOWN CLOSE TO THE SFC. CANNOT COMPLETELY RULE OUT SOME LIGHT SNOW BEING SQUEEZED OUT, SO WILL KEEP SOME LOW POPS IN FOR SUNDAY AFTERNOON AND EVENING. WHAT LITTLE MOISTURE WE HAVE DISAPPEARS AFTER 06Z, SO ANYTHING THAT IS GOING SHOULD TAPER OFF BY THEN. THE NORTHERN BRANCH OF THE UPPER TROUGH WILL CONTINUE EASTWARD INTO THE MIDWEST WHILE THE REST OF IT REMAINS OVER THE WESTERN CONUS. THE ARCTIC SFC HIGH WILL BUILD DOWN INTO THE PLAINS BY TOMORROW NIGHT, AND WITH WINDS DIMINISHING WE SHOULD GET DOWN INTO THE SINGLE DIGITS DESPITE CLOUDS. THE COLD SFC HIGH WILL REMAIN IN PLACE FOR MONDAY WITH UPSLOPE KEEPING MUCH OF OUR CLOUDS AROUND, ALTHOUGH SOME BREAKS ARE NOT OUT OF THE QUESTION. 850MB TEMPS WILL BE AROUND -10 C, AND NOT MUCH MIXING WILL BE GOING ON. WILL CONTINUE TO KEEP HIGHS RANGING FROM THE MID TEENS F IN THE NORTH TO THE LOW 20S IN THE FAR SOUTH. DAYS 3-7... ALL THE MEDIUM RANGE MODELS CONTINUE TO POINT TOWARD A WEEK MARKED BY PERIODS OF MUCH BELOW NORMAL TEMPERATURES AND A FEW PERIODS OF MAINLY LIGHT FREEZING OR FROZEN PRECIPITATION. THE GFS/ECMWF/UKMET AND CANADIAN ALL INDICATE THAT THE 500 MB RIDGE HAS SHIFTED WEST INTO THE GULF OF ALASKA AND EASTERN PACIFIC. THIS IS ALLOWING THE MEAN TROUGH POSITION TO SET UP OVER WESTERN PORTIONS OF NORTH AMERICA. OVER THE CENTRAL CONUS THE UPPER FLOW WILL HAVE A SOUTHWESTERLY COMPONENT. VERY COLD TEMPERATURES THAT WERE PUSHING DOWN INTO THE NORTHERN CONUS THIS AFTERNOON WILL PUSH SOUTH AND TAKE UP RESIDENCE OVER THE CENTRAL HIGH PLAINS THROUGH THE NEXT SEVERAL DAYS. THE HI-RES ECMWF AND GFS BOTH SHOW THIS SIGNAL. THE MODELS ALSO INDICATE A WEAK WAVE MOVING THROUGH THE UPPER FLOW ON TUESDAY AND THEN SHOW A CLOSED UPPER LOW ALONG THE WEST COAST EJECTING EASTWARD INTO THE CENTRAL PLAINS AROUND THURSDAY. THE MODELS SHOW SOME WARM ADVECTION AHEAD OF BOTH WAVE WITH ABOVE FREEZING 850 MB TEMPERATURES MOVING BACK INTO SW KANSAS. THIS FAR OUT IS WILL BE DIFFICULT TO PIN DOWN THESE FINER DETAILS IN THE TEMPERATURE FORECAST AS ANY WEAK DISTURBANCES IN THE FLOW WILL CAUSE THE ARCTIC AIR TO UNDULATE BACK AND FORTH. THE MODELS INDICATE THAT TEMPERATURES WILL CLIMB BACK ABOVE FREEZING ON THURSDAY AHEAD OF THE STRONGER WAVE BUT THERE IS A LOT OF UNCERTAINTY WITH THIS DUE TO THE NATURE OF THE ARCTIC AIR IN THE LOWER LEVELS. ONE CHANGE WAS TO INTRODUCE FREEZING PRECIPITATION TO THE FORECAST ON TUESDAY AND AGAIN WEDNESDAY NIGHT INTO THURSDAY. MODEL SOUNDINGS INDICATE THAT THE MOISTURE WILL BE FAIRLY SHALLOW...ONLY UP TO ABOUT 850 MB. WARM ADVECTION IN THE SATURATED LAYER SHOULD RESULT IN FREEZING DRIZZLE AS RETURN FLOW SETS UP AHEAD OF THE UPPER DISTURBANCES. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH MUCH OF THE PERIOD. AN ARCTIC COLD FRONT WILL PLUNGE SOUTH ACROSS SOUTHWEST KANSAS SUNDAY MORNING WITH MVFR CIGS DEVELOPING BEHIND THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... DDC 42 45 6 18 / 0 20 20 0 GCK 35 37 4 18 / 0 20 10 0 EHA 40 43 9 23 / 0 10 10 0 LBL 41 45 9 21 / 0 10 10 0 HYS 34 34 3 15 / 0 20 10 0 P28 46 55 7 20 / 0 20 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ046-065-066- 079>081-089-090. && $$ FN26/02/02 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1232 PM CST SAT DEC 13 2008 .UPDATE... PER PREVIOUS DISCUSSION/THOUGHTS AND AFTER COLLABORATION...HAVE UPGRADED TO HIGH WIND WARNING FOR A PORTION OF SOUTHEAST KANSAS AND THE FLINT HILLS UNTIL 6 PM. FREQUENT GUSTS TO 50 MPH HAVE BEEN OCCURRING...WITH INCREASED SUN/MIXING RESULTING IN POTENTIAL FOR LOCALIZED GUSTS OF 55 TO 60 MPH THIS AFTERNOON. ALSO EXPANDED THE RED FLAG WARNING FOR THE REST OF SOUTHEAST KANSAS AS WELL. KED && .PREV DISCUSSION... /ISSUED 1132 AM CST SAT DEC 13 2008/ UPDATE... VERY STRONG SOUTH WINDS WILL CONTINUE THIS AFTERNOON AND INTO THE EVENING. LOCAL PRESSURE GRADIENT MAGNITUDE OFF THE RUC/GFS ALONE SUPPORT THE GOING WIND ADVISORY...WITH ADDED CONTRIBUTION OF LOW LEVEL MIXING/MOMENTUM TRANSFER MAKING FOR HIGH END EVENT FOR AREAS EAST OF THE KANSAS TURNPIKE THIS AFTERNOON. SATELLITE TRENDS DO SUGGEST A BIT MORE SUNSHINE IS IN THE OFFING FOR THE FLINT HILLS AND SOUTHEAST KANSAS SO HAVE CONTEMPLATED THE POSSIBILITY OF AN UPGRADE TO HEADLINE. ALREADY HAVE SEEN GUST TO 55 MPH AT CFV AT 17Z...WITH THE PROFILER AT NEODESHA SHOWING 55-60KTS AT 750 METERS. WILL CONTINUE TO MONITOR TRENDS THRU 18Z AND COLLABORATE WITH ADJACENT OFFICES ON ANY POSSIBLE UPGRADE OF WIND HEADLINE. KED AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VERY STRONG SOUTH WINDS WILL CONTINUE THRU MUCH OF THE FORECAST VALID PERIOD...BEFORE A STRONG ARCTIC COLD FRONT SWEEPS SOUTH ACROSS CENTRAL KANSAS TOWARD END OF FORECAST PERIOD...WITH WIND SHIFT TO THE NORTH. VFR CONDITIONS EXPECTED...THOUGH SOME CHANCE FOR MVFR CIGS TO AFFECT SOUTHEAST KANSAS/KCNU TAF TONIGHT INTO SUNDAY MORNING AHEAD OF FRONTAL PASSAGE. KED PREV DISCUSSION... /ISSUED 544 AM CST SAT DEC 13 2008/ AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VFR CONDITIONS WILL PREVAIL FOR ALL TERMINALS INTO THE AFTERNOON HOURS...HOWEVER SOUTH WINDS WILL INCREASE DRAMATICALLY OVER SOUTH CENTRAL AND SOUTHEAST KANSAS TODAY. SUSTAINED WIND SPEEDS OVER 30KTS...WITH GUSTS AROUND 45KTS ARE EXPECTED TO AFFECT ALL TAF SITES EXCEPT FOR RSL TAF SITE WHERE WIND SPEEDS COULD BE SLIGHTLY LOWER BUT STILL GUSTY NONE THE LESS. MVFR CIGS WILL MATERIALIZE OVER CNU TAF SITE LATER THIS AFTERNOON AS LOW-LEVEL MOISTURE INCREASES...SOUTHEAST KANSAS COULD EVEN SEE SOME IFR CIGS EARLY SUNDAY MORNING. JAKUB PREV DISCUSSION... /ISSUED 345 AM CST SAT DEC 13 2008/ DISCUSSION... TODAY: ACTIVE WEATHER PATTERN UNDERWAY. SURFACE WINDS WILL GRADUALLY INCREASE THROUGHOUT THE MORNING..WITH ADVISORY CRITERIA LIKELY BEING MET PRIOR TO GOING ADVISORY AND WILL RAMP IT UP SOONER. FORECAST MEAN SEA LEVEL PRESSURE GRADIENT SUGGEST WINDS COULD FLIRT WITH WARNING CRITERIA WITH ADDITIONAL MIXING. WHERE GRADIENT IS TIGHTEST...COMBO OF CLOUDS/ROUGHER TERRAIN IN SOUTHEAST KS AND CLIMATOLOGY WOULD FAVOR HOLDING OFF ON A HIGH WIND WARNING. RAPID INFLUX OF LOW LEVEL MOISTURE TOWARDS 0000 UTC IN FAR SOUTHEAST KS COULD LEAD TO STRAY SHOWERS/SPRINKLES/DRIZZLE. GIVEN MODEL PROPENSITY TO BE FAST WITH MOISTURE AND INITIAL DRY AIR...WILL KEEP AFTERNOON FORECAST DRY AND START PRECIPITATION AT 0000 UTC. WILL ALSO EXPAND RED FLAG WARNING A BIT BASED ON LATEST FIRE DANGER GRIDS. TONIGHT: MEAN SEA LEVEL PRESSURE GRADIENT REMAINS AT OR ABOVE ADVISORY CRITERIA WELL INTO THE NIGHT AND HAVE EXTENDED IT UNTIL MIDNIGHT. SUSPECT DAY SHIFT WILL EXTEND THROUGH 1200 UTC IN FAR SOUTHEAST KS...GIVEN STOUT GRADIENT. STRONG WINDS WILL LEAD TO RATHER BALMY MINIMUMS FOR MOST AREAS. FRONT WILL LIKELY BE THROUGH RSL AT 1200 UTC AND COULD BE CLOSE TO SLN/GBD BY THEN IF FASTER EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL VERIFIES. GIVEN THE MAGNITUDE OF THE COLD AIR...THAT IS CERTAINLY POSSIBLE. SUN-SUN NIGHT: LATEST NORTH AMERICAN MODEL/GLOBAL FORECAST SYSTEM MODEL RATHER CLOSE WITH TIMING OF FRONTAL PASSAGE DURING THE DAY...BUT ARE BOTH SLOWER THAN THE 1200 UTC EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL. SUSPECT SOMETHING IN BETWEEN IS PROBABLY THE BEST BET AT THIS TIME. REGARDLESS...TEMPERATURES WILL PLUMMET BEHIND FRONT AS COLD/DRY AIR SPILLS INTO THE AREA. PRECIPITATION CHANCES ARE LOOKING LESS LIKELY IN MOISTURE AHEAD FRONT WHICH APPEARS TO BE SHIFTING EAST. BETTER CHANCES APPEAR TO BE SUN NIGHT IN WARM AIR ADVECTION AHEAD OF ELEVATED COLD FRONT. PRECIPITATION TYPE WILL TRANSITION FROM RAIN TO WINTRY MIX DURING THE EVENING GENERALLY EAST OF I-35. DO NOT EXPECT ANY SIGNIFICANT ICING OR SNOW ACCUMULATION AT THIS TIME...BUT COULD WARRANT AN ADVISORY DUE TO RAPID FREEZING OF MOISTURE ON ROADS FROM LIGHT RAIN AND/OR BRIEF FREEZING RAIN. PRECIPITATION SHOULD BE ALL SNOW BY MIDNIGHT IN SOUTHEAST KS. STARTED TRENDING DOWN DEWPOINTS...BUT LIKELY NOT FAR ENOUGH GIVEN READINGS UPSTREAM. MON-TUE: NIXED RESIDUAL CHANCES OF PRECIPITATION DURING THE DAY ON MON...BUT BOTH GLOBAL FORECAST SYSTEM MODEL/EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL SHOWING RETURN FLOW DEVELOPING WITH A BETTER CHANCE OF OVERRUNNING OVER THE ENTIRE AREA. INTIALLY IT SHOULD BE SNOW OVER THE ENTIRE AREA...BUT AS LEVELS WARM...MAY SEE SWITCH TO LIGHT FREEZING RAIN MAINLY OVER SOUTHEAST KS TUE AFTERNOON. WED-FRI: NO CHANGES TO GOING FORECAST. -HOWERTON && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 61 50 56 12 / 10 10 10 20 HUTCHINSON 61 45 50 9 / 0 10 10 20 NEWTON 60 48 56 9 / 10 10 10 20 ELDORADO 59 51 56 11 / 10 10 10 30 WINFIELD-KWLD 62 52 59 14 / 10 10 10 30 RUSSELL 63 33 33 4 / 0 10 20 20 GREAT BEND 63 37 37 4 / 0 10 20 20 SALINA 61 39 41 8 / 0 10 10 20 MCPHERSON 60 43 48 8 / 0 10 10 20 COFFEYVILLE 59 54 63 22 / 10 10 20 50 CHANUTE 58 52 61 15 / 10 10 20 40 IOLA 58 52 62 13 / 10 10 20 40 PARSONS-KPPF 58 53 62 21 / 10 10 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 6 PM CST THIS AFTERNOON FOR KSZ072- 093>096-098>100. RED FLAG WARNING UNTIL 6 PM CST THIS AFTERNOON FOR KSZ049>053- 067>072-082-083-091>096-098>100. WIND ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR KSZ072-093>096-098>100. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ047>052-067-068- 082-083-091-092. WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR KSZ053-069>071. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1132 AM CST SAT DEC 13 2008 .UPDATE... VERY STRONG SOUTH WINDS WILL CONTINUE THIS AFTERNOON AND INTO THE EVENING. LOCAL PRESSURE GRADIENT MAGNITUDE OFF THE RUC/GFS ALONE SUPPORT THE GOING WIND ADVISORY...WITH ADDED CONTRIBUTION OF LOW LEVEL MIXING/MOMENTUM TRANSFER MAKING FOR HIGH END EVENT FOR AREAS EAST OF THE KANSAS TURNPIKE THIS AFTERNOON. SATELLITE TRENDS DO SUGGEST A BIT MORE SUNSHINE IS IN THE OFFING FOR THE FLINT HILLS AND SOUTHEAST KANSAS SO HAVE CONTEMPLATED THE POSSIBILITY OF AN UPGRADE TO HEADLINE. ALREADY HAVE SEEN GUST TO 55 MPH AT CFV AT 17Z...WITH THE PROFILER AT NEODESHA SHOWING 55-60KTS AT 750 METERS. WILL CONTINUE TO MONITOR TRENDS THRU 18Z AND COLLABORATE WITH ADJACENT OFFICES ON ANY POSSIBLE UPGRADE OF WIND HEADLINE. KED && .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VERY STRONG SOUTH WINDS WILL CONTINUE THRU MUCH OF THE FORECAST VALID PERIOD...BEFORE A STRONG ARCTIC COLD FRONT SWEEPS SOUTH ACROSS CENTRAL KANSAS TOWARD END OF FORECAST PERIOD...WITH WIND SHIFT TO THE NORTH. VFR CONDITIONS EXPECTED...THOUGH SOME CHANCE FOR MVFR CIGS TO AFFECT SOUTHEAST KANSAS/KCNU TAF TONIGHT INTO SUNDAY MORNING AHEAD OF FRONTAL PASSAGE. KED && .PREV DISCUSSION... /ISSUED 544 AM CST SAT DEC 13 2008/ AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VFR CONDITIONS WILL PREVAIL FOR ALL TERMINALS INTO THE AFTERNOON HOURS...HOWEVER SOUTH WINDS WILL INCREASE DRAMATICALLY OVER SOUTH CENTRAL AND SOUTHEAST KANSAS TODAY. SUSTAINED WIND SPEEDS OVER 30KTS...WITH GUSTS AROUND 45KTS ARE EXPECTED TO AFFECT ALL TAF SITES EXCEPT FOR RSL TAF SITE WHERE WIND SPEEDS COULD BE SLIGHTLY LOWER BUT STILL GUSTY NONE THE LESS. MVFR CIGS WILL MATERIALIZE OVER CNU TAF SITE LATER THIS AFTERNOON AS LOW-LEVEL MOISTURE INCREASES...SOUTHEAST KANSAS COULD EVEN SEE SOME IFR CIGS EARLY SUNDAY MORNING. JAKUB PREV DISCUSSION... /ISSUED 345 AM CST SAT DEC 13 2008/ DISCUSSION... TODAY: ACTIVE WEATHER PATTERN UNDERWAY. SURFACE WINDS WILL GRADUALLY INCREASE THROUGHOUT THE MORNING..WITH ADVISORY CRITERIA LIKELY BEING MET PRIOR TO GOING ADVISORY AND WILL RAMP IT UP SOONER. FORECAST MEAN SEA LEVEL PRESSURE GRADIENT SUGGEST WINDS COULD FLIRT WITH WARNING CRITERIA WITH ADDITIONAL MIXING. WHERE GRADIENT IS TIGHTEST...COMBO OF CLOUDS/ROUGHER TERRAIN IN SOUTHEAST KS AND CLIMATOLOGY WOULD FAVOR HOLDING OFF ON A HIGH WIND WARNING. RAPID INFLUX OF LOW LEVEL MOISTURE TOWARDS 0000 UTC IN FAR SOUTHEAST KS COULD LEAD TO STRAY SHOWERS/SPRINKLES/DRIZZLE. GIVEN MODEL PROPENSITY TO BE FAST WITH MOISTURE AND INITIAL DRY AIR...WILL KEEP AFTERNOON FORECAST DRY AND START PRECIPITATION AT 0000 UTC. WILL ALSO EXPAND RED FLAG WARNING A BIT BASED ON LATEST FIRE DANGER GRIDS. TONIGHT: MEAN SEA LEVEL PRESSURE GRADIENT REMAINS AT OR ABOVE ADVISORY CRITERIA WELL INTO THE NIGHT AND HAVE EXTENDED IT UNTIL MIDNIGHT. SUSPECT DAY SHIFT WILL EXTEND THROUGH 1200 UTC IN FAR SOUTHEAST KS...GIVEN STOUT GRADIENT. STRONG WINDS WILL LEAD TO RATHER BALMY MINIMUMS FOR MOST AREAS. FRONT WILL LIKELY BE THROUGH RSL AT 1200 UTC AND COULD BE CLOSE TO SLN/GBD BY THEN IF FASTER EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL VERIFIES. GIVEN THE MAGNITUDE OF THE COLD AIR...THAT IS CERTAINLY POSSIBLE. SUN-SUN NIGHT: LATEST NORTH AMERICAN MODEL/GLOBAL FORECAST SYSTEM MODEL RATHER CLOSE WITH TIMING OF FRONTAL PASSAGE DURING THE DAY...BUT ARE BOTH SLOWER THAN THE 1200 UTC EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL. SUSPECT SOMETHING IN BETWEEN IS PROBABLY THE BEST BET AT THIS TIME. REGARDLESS...TEMPERATURES WILL PLUMMET BEHIND FRONT AS COLD/DRY AIR SPILLS INTO THE AREA. PRECIPITATION CHANCES ARE LOOKING LESS LIKELY IN MOISTURE AHEAD FRONT WHICH APPEARS TO BE SHIFTING EAST. BETTER CHANCES APPEAR TO BE SUN NIGHT IN WARM AIR ADVECTION AHEAD OF ELEVATED COLD FRONT. PRECIPITATION TYPE WILL TRANSITION FROM RAIN TO WINTRY MIX DURING THE EVENING GENERALLY EAST OF I-35. DO NOT EXPECT ANY SIGNIFICANT ICING OR SNOW ACCUMULATION AT THIS TIME...BUT COULD WARRANT AN ADVISORY DUE TO RAPID FREEZING OF MOISTURE ON ROADS FROM LIGHT RAIN AND/OR BRIEF FREEZING RAIN. PRECIPITATION SHOULD BE ALL SNOW BY MIDNIGHT IN SOUTHEAST KS. STARTED TRENDING DOWN DEWPOINTS...BUT LIKELY NOT FAR ENOUGH GIVEN READINGS UPSTREAM. MON-TUE: NIXED RESIDUAL CHANCES OF PRECIPITATION DURING THE DAY ON MON...BUT BOTH GLOBAL FORECAST SYSTEM MODEL/EUROPEAN CENTRE FOR MEDIUM RANGE WEATHER FORECASTS MODEL SHOWING RETURN FLOW DEVELOPING WITH A BETTER CHANCE OF OVERRUNNING OVER THE ENTIRE AREA. INTIALLY IT SHOULD BE SNOW OVER THE ENTIRE AREA...BUT AS LEVELS WARM...MAY SEE SWITCH TO LIGHT FREEZING RAIN MAINLY OVER SOUTHEAST KS TUE AFTERNOON. WED-FRI: NO CHANGES TO GOING FORECAST. -HOWERTON && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 61 50 56 12 / 10 10 10 20 HUTCHINSON 61 45 50 9 / 0 10 10 20 NEWTON 60 48 56 9 / 10 10 10 20 ELDORADO 59 51 56 11 / 10 10 10 30 WINFIELD-KWLD 62 52 59 14 / 10 10 10 30 RUSSELL 63 33 33 4 / 0 10 20 20 GREAT BEND 63 37 37 4 / 0 10 20 20 SALINA 61 39 41 8 / 0 10 10 20 MCPHERSON 60 43 48 8 / 0 10 10 20 COFFEYVILLE 59 54 63 22 / 10 20 20 50 CHANUTE 58 52 61 15 / 10 20 20 40 IOLA 58 52 62 13 / 10 20 20 40 PARSONS-KPPF 58 53 62 21 / 10 20 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR KSZ053-069>072- 093>096-098>100. RED FLAG WARNING UNTIL 6 PM CST THIS AFTERNOON FOR KSZ049>053- 067>072-082-083-091>094-098. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ047>052-067-068- 082-083-091-092. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1248 PM EST SUN DEC 14 2008 .SHORT TERM.../THE REST OF TODAY/ WINDS CONTINUE TO INCREASE THIS MORNING WITH A TIGHTENING PRESSURE GRADIENT...AND WINDS ALOFT BEGINNING TO MIX DOWN TO THE SURFACE. HAVE ALREADY HAD SOME GUSTS APPROACHING 40 MPH. OCCASIONAL GUSTS TO 45 MPH ARE EXPECTED TO CONTINUE AT LEAST THROUGH THE AFTERNOON...AND POSSIBLY EARLY EVENING. THIS COULD BRING DOWN A FEW TREES AND POWER LINES. INCREASED CLOUD COVER TODAY...ESPECIALLY IN THE NORTHWEST... WHERE AC CONTINUES TO MOVE ACROSS THE AREA. LOOKING AT SATELLITE IMAGES AND RUC13 MOISTURE FIELDS...THINK THESE CLOUDS WILL PERSIST THROUGH THE DAY. ELSEWHERE...AN INCREASE IN CLOUD COVER CAN BE EXPECTED. OTHER THAN MOSTLY CLOUDY IN THE NORTHWEST...WILL GO WITH PARTLY SUNNY WORDING TODAY FOR AN AVERAGE SKY COVER AS MID AND HIGH CLOUDS MOVE IN. TEMPS HAVE RISEN QUICKLY THIS MORNING...WITH EVEN THE COLDEST VALLEYS RAPIDLY REACHING THE 40S SO FAR. TWEAKED AFTERNOON HIGHS SOME BASED ON THE LATEST UPPER AIR DATA AND CURRENT TRENDS. UPDATED FORECAST PRODUCTS OUT SOON. THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS... /TODAY THROUGH TONIGHT/ WAA ALREADY EVIDENT WITH SRLY FLOW AND TEMPS ONLY IN THE MID TO UPPER 30S ATTM. GUSTY WINDS SHOWING UP ON SOME OF THE RIDGETOP OBS IN TN AND ON THE CUMBERLAND PLATEAU. OTHERWISE...WINDS GUSTY FROM MIE TO SDF TO BWG TO MKL. NOTHING YET TO MEET NPW (WIND ADV) CRITERIA YET BUT THIS SHOULD CHANGE AFTER SUNRISE. STILL HAVE SOME SNOW IN OUR CNTRL ZONES TO GET RID OF SO TEMPS WILL BE SLOW TO CLIMB BUT SHOULD MAKE IT TO AT LEAST THE LOWER 50S IN OUR SNOW BELT ON THE ERN SIDE OF THE DAN BOONE NAT FOREST. ELSEWHERE...EXPECT MID 50S FOR HIGHS TODAY. HAVE UNDERCUT MOS TEMPS SLIGHTLY AS THEY SEEM TO HAVE BEEN OUT OF TOUCH WITH CURRENT SURFACE CONDITIONS. WITH THE EXPECTED WINDS TODAY I AM ALSO EXPECTING OVERNIGHT TEMPS TO REMAIN RELATIVELY FLAT AS THE TYPICAL NOCTURNAL INVERSION WILL BE LATE TO ESTABLISH ...IF AT ALL. .LONG TERM.../MONDAY THROUGH SATURDAY/ THE MODELS ARE IN DECENT AGREEMENT ALOFT CONSIDERING THE COMPLEXITY OF THE FORECAST IN THE LONG TERM. A LARGE UPPER LEVEL RIDGE WILL HOLD ON OVER THE GULF OF MEXICO AND EXTEND ITS INFLUENCE NORTHEAST ALONG THE SOUTHEAST ATLANTIC COASTAL STATES DURING THE BREADTH OF THIS PERIOD. IT WILL BE NUDGED AND BUFFETED FROM THE NORTHWEST BY A SEEMINGLY ENDLESS STRING OF SHORTWAVES RUNNING FROM THE BASE OF THE DEEP TROUGH OVER THE DESERT SOUTHWEST NORTHEAST IN FAST AND BROAD SOUTHWEST FLOW THROUGH THE LOWER MISSISSIPPI VALLEY UP INTO THE OHIO VALLEY AND THEN TO EASTERN CANADA. NOT SURPRISINGLY...THESE WAVES ARE ILL TIMED AND DEFINED AMONGST THE MODELS. A BLENDED SOLUTION WAS FOLLOWED...THOUGH THE UPPER PATTERN WILL BE FAR LESS IMPORTANT TO THIS FORECAST THAN IT NORMAL IS...GIVEN THE DETERMINATIVE ARCTIC AIR AIR MASS SLOSHING AROUND IN OUR NEIGHBORHOOD BENEATH THE UPPER PATTERN. TO THAT END...THE DAY TO DAY EXTENT AND MOVEMENT OF THE COLD AIR IN THE LOWEST LAYERS OF THE ATMOSPHERE WILL BE A CRITICAL FACTOR IN PRECIPITATION TYPE THROUGH THE EXTENDED PORTION OF THIS FAIRLY WET FORECAST. EARLY ON...A BLEND OF OUR PREVIOUS FORECAST AND THE NAM12 WAS FOLLOWED BEFORE MORE OF A BLEND FROM THE LATEST GFS AND 12Z ECMWF WAS PREFERRED FROM TUESDAY ON THROUGH SATURDAY. INITIALLY...THIS RESULTED IN A PUSH OF ARCTIC AIR FURTHER EAST THAN DEPICTED BY THE INHERITED GRIDS AND THE GFS. FOLLOWING THAT...LATER IN THE WEEK...THE SLOSHING OF THE ARCTIC AIR WILL BE BASED MORE ON THE SFC PRESSURE FEATURES AND THE RESULTING PATTERN. ACCORDINGLY...FOLLOWED A BLEND OF THE HPC PATTERN AND THE MID RANGE MODELS. SENSIBLE WEATHER WILL FEATURE AN EXTREME OSCILLATION OF COLD AIR AND ITS RESULTS ON THE PRECIPITATION BETWEEN PERIODS OF WARMTH AS LOW PRESSURE WAVES PASS THROUGH THE AREA...RUNNING ALONG THE BAROCLINIC ZONE. THIS WILL ALSO BE A WET PERIOD WITH THE GULF OF MEXICO FEEDING MOISTURE NORTHEAST WITHIN THE BROAD AND FAST...DEEP LAYER...SOUTHWEST FLOW. SPECIFICALLY...THE ARCTIC AIR WILL PRESS INTO THE CWA FROM THE NORTHWEST LATER MONDAY AS SHOWERS STREAM ALONG AND AHEAD OF THE FRONT. THE UNDERCUTTING COLD WILL BE ENOUGH FOR A THREAT OF MIXED PRECIPITATION OVER A GOOD PORTION OF THE AREA MONDAY NIGHT... LINGERING INTO THE MORNING TUESDAY. THE NEXT WAVE THEN SENDS WARMER AIR BACK NORTH LATER TUESDAY WHILE THE CHANCE FOR LIQUID PCPN CONTINUES. THIS WAVE PASSES ON WEDNESDAY DRAGGING THE COLD AIR AND ANOTHER THREAT FOR LINGERING MIXED PCPN WEDNESDAY NIGHT INTO THURSDAY MORNING. FOR THURSDAY PROPER...THE NEXT SFC WAVE SENDS WARM AIR BACK NORTH...LASTING INTO THE NIGHT WITH COLD AIR PUSHING BACK INTO THE REGION ON FRIDAY NIGHT...BUT NOT QUITE ENOUGH...AT THIS POINT FOR MIXED PCPN FROM THE OVER RUNNING PCPN THAT WILL WORK BACK OVER THE AREA ON SATURDAY...ALL THE WHILE BRINGING THE NEXT BRIEF SURGE OF WARM AIR NORTHWARD. AS IT LOOKS NOW...THE GREATEST THREAT FOR MIXED PCPN WILL BE MONDAY NIGHT INTO TUESDAY MORNING WITH A LESSER THREAT WEDNESDAY NIGHT. WAVES OF MOIST AIR WILL KEEP THE CHANCE OF RAIN GOING FOR MUCH OF THE TIME THROUGH THE EXTENDED. GIVEN THE NATURE OF THE ARCTIC AIR AFFECTING US EARLY ON...FOLLOWED MORE OF A TEMPERATURE CURVE AND SPECIFIC VALUES FROM THE RAW NAM12. THIS RESULTED IN TEMPS CLOSER TO THE MET NUMBERS MONDAY NIGHT RATHER THAN THE MAV. LATER ON...BLENDED THE RAW ECMWF AND GFS TEMPS RESULTING IN MORE MODERATED MAX AND MIN TEMPS IN THAT PART OF THE EXTENDED THAN THE MEX NUMBERS. AS FOR POPS...ENDED UP WITH MORE OF A BLEND OF THE MAV AND MET THROUGH THE FIRST PART OF THE LONG RANGE AND THEN NOT QUITE AS HIGH AS THE MEX THROUGH SATURDAY. && .AVIATION.../18Z TO 18Z/...UPDATED WINDS ARE THE MAIN CONCERN TODAY INTO TONIGHT...AS A TIGHT PRESSURE GRADIENT EXISTS BETWEEN HIGH PRESSURE TO OUR EAST AND A COLD FRONT FROM THE UPPER MIDWEST TO THE PLAINS. SOUTH WINDS WITH GUSTS NEAR 40 KT WILL CONTINUE THROUGH THE AFTERNOON...WITH SOME MID AND HIGH CLOUDS MOVING INTO THE AREA. THE SURFACE GUSTS WILL SUBSIDE IN THE VALLEYS TONIGHT...BUT WINDS ABOVE THE SURFACE STRENGTHEN SOME. WILL INCLUDE WIND SHEAR FOR LOZ AND SME...BUT WILL KEEP GUSTS TO AROUND 25 KT AT JKL ON THE RIDGE TOP. SURFACE WINDS WILL BECOME GUSTY AGAIN AS THE FRONT APPROACHES ON MONDAY. SOUTHWEST WINDS GUSTING TO 25 KT ARE EXPECTED...WITH STRATOCU AND A FEW -SHRA MOVING IN AFTER 15Z. EXPECTING LOWER CIGS AND VIS AFTER THE END OF THE TAF PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...DUSTY/WJM LONG TERM....GREIF AVIATION...WJM ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1044 AM EST SUN DEC 14 2008 .SHORT TERM.../THE REST OF TODAY/...UPDATED WINDS CONTINUE TO INCREASE THIS MORNING WITH A TIGHTENING PRESSURE GRADIENT...AND WINDS ALOFT BEGINNING TO MIX DOWN TO THE SURFACE. HAVE ALREADY HAD SOME GUSTS APPROACHING 40 MPH. OCCASIONAL GUSTS TO 45 MPH ARE EXPECTED TO CONTINUE AT LEAST THROUGH THE AFTERNOON...AND POSSIBLY EARLY EVENING. THIS COULD BRING DOWN A FEW TREES AND POWER LINES. INCREASED CLOUD COVER TODAY...ESPECIALLY IN THE NORTHWEST... WHERE AC CONTINUES TO MOVE ACROSS THE AREA. LOOKING AT SATELLITE IMAGES AND RUC13 MOISTURE FIELDS...THINK THESE CLOUDS WILL PERSIST THROUGH THE DAY. ELSEWHERE...AN INCREASE IN CLOUD COVER CAN BE EXPECTED. OTHER THAN MOSTLY CLOUDY IN THE NORTHWEST...WILL GO WITH PARTLY SUNNY WORDING TODAY FOR AN AVERAGE SKY COVER AS MID AND HIGH CLOUDS MOVE IN. TEMPS HAVE RISEN QUICKLY THIS MORNING...WITH EVEN THE COLDEST VALLEYS RAPIDLY REACHING THE 40S SO FAR. TWEAKED AFTERNOON HIGHS SOME BASED ON THE LATEST UPPER AIR DATA AND CURRENT TRENDS. UPDATED FORECAST PRODUCTS OUT SOON. THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS... /TODAY THROUGH TONIGHT/ WAA ALREADY EVIDENT WITH SRLY FLOW AND TEMPS ONLY IN THE MID TO UPPER 30S ATTM. GUSTY WINDS SHOWING UP ON SOME OF THE RIDGETOP OBS IN TN AND ON THE CUMBERLAND PLATEAU. OTHERWISE...WINDS GUSTY FROM MIE TO SDF TO BWG TO MKL. NOTHING YET TO MEET NPW (WIND ADV) CRITERIA YET BUT THIS SHOULD CHANGE AFTER SUNRISE. STILL HAVE SOME SNOW IN OUR CNTRL ZONES TO GET RID OF SO TEMPS WILL BE SLOW TO CLIMB BUT SHOULD MAKE IT TO AT LEAST THE LOWER 50S IN OUR SNOW BELT ON THE ERN SIDE OF THE DAN BOONE NAT FOREST. ELSEWHERE...EXPECT MID 50S FOR HIGHS TODAY. HAVE UNDERCUT MOS TEMPS SLIGHTLY AS THEY SEEM TO HAVE BEEN OUT OF TOUCH WITH CURRENT SURFACE CONDITIONS. WITH THE EXPECTED WINDS TODAY I AM ALSO EXPECTING OVERNIGHT TEMPS TO REMAIN RELATIVELY FLAT AS THE TYPICAL NOCTURNAL INVERSION WILL BE LATE TO ESTABLISH ...IF AT ALL. .LONG TERM.../MONDAY THROUGH SATURDAY/ THE MODELS ARE IN DECENT AGREEMENT ALOFT CONSIDERING THE COMPLEXITY OF THE FORECAST IN THE LONG TERM. A LARGE UPPER LEVEL RIDGE WILL HOLD ON OVER THE GULF OF MEXICO AND EXTEND ITS INFLUENCE NORTHEAST ALONG THE SOUTHEAST ATLANTIC COASTAL STATES DURING THE BREADTH OF THIS PERIOD. IT WILL BE NUDGED AND BUFFETED FROM THE NORTHWEST BY A SEEMINGLY ENDLESS STRING OF SHORTWAVES RUNNING FROM THE BASE OF THE DEEP TROUGH OVER THE DESERT SOUTHWEST NORTHEAST IN FAST AND BROAD SOUTHWEST FLOW THROUGH THE LOWER MISSISSIPPI VALLEY UP INTO THE OHIO VALLEY AND THEN TO EASTERN CANADA. NOT SURPRISINGLY...THESE WAVES ARE ILL TIMED AND DEFINED AMONGST THE MODELS. A BLENDED SOLUTION WAS FOLLOWED...THOUGH THE UPPER PATTERN WILL BE FAR LESS IMPORTANT TO THIS FORECAST THAN IT NORMAL IS...GIVEN THE DETERMINATIVE ARCTIC AIR AIR MASS SLOSHING AROUND IN OUR NEIGHBORHOOD BENEATH THE UPPER PATTERN. TO THAT END...THE DAY TO DAY EXTENT AND MOVEMENT OF THE COLD AIR IN THE LOWEST LAYERS OF THE ATMOSPHERE WILL BE A CRITICAL FACTOR IN PRECIPITATION TYPE THROUGH THE EXTENDED PORTION OF THIS FAIRLY WET FORECAST. EARLY ON...A BLEND OF OUR PREVIOUS FORECAST AND THE NAM12 WAS FOLLOWED BEFORE MORE OF A BLEND FROM THE LATEST GFS AND 12Z ECMWF WAS PREFERRED FROM TUESDAY ON THROUGH SATURDAY. INITIALLY...THIS RESULTED IN A PUSH OF ARCTIC AIR FURTHER EAST THAN DEPICTED BY THE INHERITED GRIDS AND THE GFS. FOLLOWING THAT...LATER IN THE WEEK...THE SLOSHING OF THE ARCTIC AIR WILL BE BASED MORE ON THE SFC PRESSURE FEATURES AND THE RESULTING PATTERN. ACCORDINGLY...FOLLOWED A BLEND OF THE HPC PATTERN AND THE MID RANGE MODELS. SENSIBLE WEATHER WILL FEATURE AN EXTREME OSCILLATION OF COLD AIR AND ITS RESULTS ON THE PRECIPITATION BETWEEN PERIODS OF WARMTH AS LOW PRESSURE WAVES PASS THROUGH THE AREA...RUNNING ALONG THE BAROCLINIC ZONE. THIS WILL ALSO BE A WET PERIOD WITH THE GULF OF MEXICO FEEDING MOISTURE NORTHEAST WITHIN THE BROAD AND FAST...DEEP LAYER...SOUTHWEST FLOW. SPECIFICALLY...THE ARCTIC AIR WILL PRESS INTO THE CWA FROM THE NORTHWEST LATER MONDAY AS SHOWERS STREAM ALONG AND AHEAD OF THE FRONT. THE UNDERCUTTING COLD WILL BE ENOUGH FOR A THREAT OF MIXED PRECIPITATION OVER A GOOD PORTION OF THE AREA MONDAY NIGHT... LINGERING INTO THE MORNING TUESDAY. THE NEXT WAVE THEN SENDS WARMER AIR BACK NORTH LATER TUESDAY WHILE THE CHANCE FOR LIQUID PCPN CONTINUES. THIS WAVE PASSES ON WEDNESDAY DRAGGING THE COLD AIR AND ANOTHER THREAT FOR LINGERING MIXED PCPN WEDNESDAY NIGHT INTO THURSDAY MORNING. FOR THURSDAY PROPER...THE NEXT SFC WAVE SENDS WARM AIR BACK NORTH...LASTING INTO THE NIGHT WITH COLD AIR PUSHING BACK INTO THE REGION ON FRIDAY NIGHT...BUT NOT QUITE ENOUGH...AT THIS POINT FOR MIXED PCPN FROM THE OVER RUNNING PCPN THAT WILL WORK BACK OVER THE AREA ON SATURDAY...ALL THE WHILE BRINGING THE NEXT BRIEF SURGE OF WARM AIR NORTHWARD. AS IT LOOKS NOW...THE GREATEST THREAT FOR MIXED PCPN WILL BE MONDAY NIGHT INTO TUESDAY MORNING WITH A LESSER THREAT WEDNESDAY NIGHT. WAVES OF MOIST AIR WILL KEEP THE CHANCE OF RAIN GOING FOR MUCH OF THE TIME THROUGH THE EXTENDED. GIVEN THE NATURE OF THE ARCTIC AIR AFFECTING US EARLY ON...FOLLOWED MORE OF A TEMPERATURE CURVE AND SPECIFIC VALUES FROM THE RAW NAM12. THIS RESULTED IN TEMPS CLOSER TO THE MET NUMBERS MONDAY NIGHT RATHER THAN THE MAV. LATER ON...BLENDED THE RAW ECMWF AND GFS TEMPS RESULTING IN MORE MODERATED MAX AND MIN TEMPS IN THAT PART OF THE EXTENDED THAN THE MEX NUMBERS. AS FOR POPS...ENDED UP WITH MORE OF A BLEND OF THE MAV AND MET THROUGH THE FIRST PART OF THE LONG RANGE AND THEN NOT QUITE AS HIGH AS THE MEX THROUGH SATURDAY. && .AVIATION.../06Z TO 06Z/ HIGH PRESSURE WILL CONTINUE TO GIVE WAY TO A DEVELOPING STORM SYSTEM THAT IS BREWING IN THE NORTHERN PLAINS. AS THE HIGH WEAKENS AND MOVES OFF TO THE EAST SUNDAY EVENING AND NIGHT...SCATTERED TO BROKEN MIDDLE AND HIGH LEVEL CLOUD COVER WILL OVERSPREAD THE AREA FROM THE WEST. VFR CONDITIONS WILL CONTINUE TO PREVAIL THROUGH THE END OF THE TAF PERIOD AT ALL THREE TAF SITES. THE PRIMARY AVIATION CONCERN WILL BE WINDS. DURING THE OVERNIGHT HOURS TONIGHT...LOW LEVEL WIND SHEAR WILL BE AN ISSUE. THE LATEST NAM12 FORECAST SOUNDINGS ARE SHOWING A DESCENDING LAYER OF 35-45KT WINDS BEGINNING AT 8Z. THE 15/0Z 850 HPA CHART SUPPORTS THIS SCENARIO AS WELL...WITH A DISTINCT 55-70 KT LOW LEVEL JET CORE MOVING IN FROM THE CENTRAL PLAINS AND ACROSS THE MID MISSISSIPPI RIVER VALLEY. WINDS ALONG THE LEADING EDGE OF THE LLJ ARE IN THE 30-50 KT RANGE...AND AGAIN SUPPORT THE LOW LEVEL WIND SHEAR MENTIONED IN THE 6Z TAF. WINDS WILL BE CRITICAL DURING THE DAY TODAY AS WELL...WITH GUSTS UP TO 45 MPH POSSIBLE BETWEEN 18 AND 22Z...AS THE STRENGTHENING LOW LEVEL JET MOVES ACROSS THE OHIO VALLEY...AND THE PRESSURE GRADIENT BETWEEN THE DEPARTING HIGH AND THE APPROACHING LOW BEGINS TO TIGHTEN. IN FACT...A WIND ADVISORY HAS BEEN ISSUED TO ADDRESS THE POTENTIAL FOR STRONG WINDS LATER TODAY. ANY PRECIPITATION ASSOCIATED WITH THE DEVELOPING NORTHERN PLAINS STORM...WILL NOT MAKE IT INTO THE FORECAST AREA UNTIL MONDAY MORNING. && .JKL WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...DUSTY/WJM LONG TERM....GREIF AVIATION...AR ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 933 PM EST SAT DEC 13 2008 .SYNOPSIS... HIGH PRESSURE WILL CROSS THE REGION TONIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. CLOUDS WILL MOVE IN FROM THE WEST SUNDAY INTO MONDAY WHILE WARMER AIR BEGINS TO MOVE ACROSS THE REGION. A COLD FRONT WILL CROSS THE REGION MONDAY NIGHT...WITH HIGH PRESSURE BUILDING EAST LATER TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... SEE MARINE SECTION. UPDATED THE GRIDS/ZFP TONIGHT FOR TEMPS TO DROP THEM BACK ESP DOWNEAST AND EASTERN SECTIONS. LATEST RUC13 SFC TEMPS SPOT ON FOR THE MOST PART W/READINGS ACROSS THE N AND W ALREADY DROPPING BELOW ZERO. DOWNEAST AND THE COAST FALLING BACK INTO THE LOWER TEENS ATTM AND STILL PLENTY OF TIME FOR MORE DROP TO HAPPEN. THEREFORE...WENT W/10-15 BELOW ACROSS THE FAR N AND W ESP SAINT JOHN VALLEY...HOULTON AND NORTHERN WASHINGTON COUNTY WHERE COLD AIR DRAINAGE WILL OCCUR. 10 TO 15 BELOW IN SOME OF THESE AREAS NOT OUT OF THE QUESTION. DECIDED ON SINGLE NUMBERS W/SOME AREAS SEEING AROUND ZERO FOR THE INTERIOR DOWNEAST AND THE COAST. CLOUDS MOVING IN FROM THE W WILL ALLOW TEMPS TO LEVEL OFF ACROSS THE W AND NW BY SUNDAY MORNING. CONVECTIVE STRATOCUMULUS ACROSS NORTHERN AND CENTRAL SECTIONS WILL DISSIPATE LATER THIS AFTERNOON WITH DECREASE IN SOLAR RADIATION. COULDN`T RULE OUT SOME SCATTERED FLURRIES BEFORE CLOUDS DISSIPATE. CLEAR SKIES AND LIGHT WINDS FOR MOST OF THE REGION TONIGHT WILL ALLOW STRONG RADIATIONAL COOLING WITH TEMPERATURES DROPPING TO BELOW ZERO ACROSS THE NORTH AND CENTRAL SECTIONS WITH SINGLE DIGITS FOR DOWNEAST. PREFER THE COLDER FWC GUIDANCE AS MET AND MAV HAVE BEEN TOO WARM FOR TEMPERATURES TODAY. AS HIGH PRESSURE MOVES EAST OF THE REGION AFTER MIDNIGHT...MID AND HIGH CLOUDS WILL APPROACH FROM THE WEST WHICH MAY PREVENT TEMPERATURES FROM REALLY BOMBING OVER EXTREME WESTERN SECTIONS. WARM AIR ADVECTION MID AND HIGH CLOUDS WILL QUICKLY OVERSPREAD THE REGION AFTER SUNRISE SUNDAY CREATING A MOSTLY CLOUDY TO OVERCAST DAY. A WEAK DISTURBANCE IN THE FLOW ALOFT MAY BE ENOUGH TO CREATE SOME LIGHT SNOW ACROSS THE NORTH SUNDAY AFTERNOON BUT ANY AMOUNTS WILL BE VERY LIGHT. && .SHORT TERM /SUNDAY NIGHT/... HIGH PRESSURE WILL MOVE TO THE EAST SUNDAY NIGHT WHILE LOW PRESSURE LIFTS THROUGH THE GREAT LAKES. WARM AIR ADVECTION BETWEEN THESE SYSTEMS WILL BRING MOSTLY CLOUDY SKIES TO THE REGION. ACROSS NORTHERN AREAS...THERE IS A CHANCE OF LIGHT SNOW TRANSITIONING TO LIGHT FREEZING RAIN SUNDAY NIGHT WITH TEMPERATURES WARMING THROUGH THE NIGHT AT BOTH THE SURFACE AND ALOFT. THE LOW WILL TRACK NORTHWEST OF THE REGION MONDAY...DRAWING A COLD FRONT TOWARD WESTERN MAINE LATE. LIGHT FREEZING RAIN COULD LINGER ACROSS NORTHERN AREAS EARLY MONDAY MORNING. OTHERWISE...TEMPERATURES WILL BE WARM ENOUGH FOR RAIN ACROSS THE ENTIRE REGION WITH INCREASING RAIN CHANCES DURING THE AFTERNOON IN ADVANCE OF THE APPROACHING COLD FRONT. THE COLD FRONT WILL CROSS THE FORECAST AREA MONDAY NIGHT. RAIN SHOWERS WILL OCCUR IN ADVANCE OF THE COLD FRONT...WITH THE PRECIPITATION TRANSITIONING TO SNOW SHOWERS IN THE WAKE OF THE COLD FRONT. THE TRANSITION TO SNOW WILL INITIALLY OCCUR ACROSS NORTHERN AREAS...NOT REACHING THE DOWNEAST COAST UNTIL LATE. SNOW SHOWERS COULD LINGER EARLY TUESDAY...WITH CLOUD COVER THEN DIMINISHING WHILE HIGH PRESSURE BUILDS EAST. HIGH PRESSURE WILL CROSS THE REGION TUESDAY NIGHT. CLOUD COVER WILL THEN BEGIN TO INCREASE LATER TUESDAY NIGHT TO THE NORTH OF LOW PRESSURE TRACKING SOUTH OF THE REGION...WITH A CHANCE OF LIGHT SNOW LATE ACROSS CENTRAL/DOWNEAST PORTIONS OF THE FORECAST AREA. TEMPERATURES WILL BE AT ABOVE NORMAL LEVELS MONDAY...WITH NEAR NORMAL LEVEL TEMPERATURES TUESDAY. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE START OF THE LONG TERM FINDS THE GFS AND ECMWF IN GOOD GENERAL AGREEMENT. A HIGH PRESSURE SYSTEM WILL BE RIDGED ACROSS THE REGION. BY MIDDAY ON WED THE HIGH WILL HAVE MOVED TO THE E. THE MODELS ARE A BIT AT ODDS WITH POSITION OF THE LOW THE GFS HAS THE LOW OVER THE SRN GULF OF MAINE WATERS...THE ECMWF HAS THE LOW TRACKING E ALONG THE COAST OF MAINE. BY THUR MORNING THE LOW WILL BE E OF THE AREA OVER THE CANADIAN MARITIMES...WITH THE FRONT EXTENDING BACK ACROSS THE S GULF OF MAINE WATERS. THE MODELS ARE AGAIN IN GENERAL AGREEMENT...BUT THE TIMING IS A BIT OFF ABOUT 6 HRS OUT OF PHASE. THE NEXT LOW WILL TRACK INTO THE AREA FRI MORN ACCORDING TO THE GFS...FRI AFTERNOON ECMWF. OTHER THAN TIMING ISSUES THE POSITION AND MOVEMENT ARE SIMILAR. BY 06Z SAT THE LOW WILL BE EAST OF THE AREA AND HIGHER PRESS WILL ONCE AGAIN BUILD ACROSS THE AREA. LOADED THE GMOS AND ADJUSTED SKY AND POPS TO BETTER SUPPORT ONE ANOTHER. SOME UNCERTAINTY REMAINS THROUGH THE MIDDLE PORTION OF THE LONG TERM AS TO THE TRACK OF THE LOW. THE GFS TRACK WOULD BRING THE PRECIP BAND FARTHER N INTO CTRL ME...WERE THE ECMWF`S TRACK WOULD TAKE IT FARTHER S CONFINING THE PRECIP TO THE COASTAL AREA. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... MVFR CEILINGS OVER THE NORTH WILL DISSIPATE LATER THIS AFTERNOON WITH CLEAR CONDITIONS FOR THE ENTIRE AREA TONIGHT. MID AND HIGH CLOUDS WILL QUICKLY OVERSPREAD THE REGION ON SUNDAY BUT CONDITIONS TO REMAIN VFR. CEILINGS/VISIBILITIES SHOULD LOWER TO MVFR LEVELS ACROSS NORTHERN AREAS LATER SUNDAY NIGHT...WITH GENERALLY VFR CONDITIONS ACROSS THE REST OF THE REGION. OCCASIONAL MVFR CONDITIONS WILL OCCUR ACROSS NORTHERN AREAS MONDAY...WITH OCCASIONAL MVFR CONDITIONS DEVELOPING DOWNEAST. MVFR/IFR CONDITIONS ARE EXPECTED MONDAY NIGHT WITH THE COLD FRONT CROSSING THE REGION. CONDITIONS WILL IMPROVE TO VFR LEVELS TUESDAY. OCCASIONAL MVFR CONDITIONS COULD THEN OCCUR ACROSS THE REGION WITH SNOW SHOWERS WEDNESDAY THROUGH EARLY THURSDAY. && .MARINE... NEAR TERM: EXTENDED THE SCA UNTIL 10Z FOR OUTER MARINE ZONES PER COLLABORATION W/GYX. WINDS/SEAS HOLDING AOA SCA LEVELS. THE GUIDANCE IS TOO FAST IN BRINGING THE CONDITIONS DOWN PER 00Z OBS. CONDITIONS IN THE INLETS HAVE DROPPED BELOW SCA CRITERIA SO WILL DROP SCA FOR ANZ052 WITH THIS ISSUANCE. USED A BLEND OF THE GFS AND NAM12 FOR WINDS AND A BLEND OF THE WNAWAVE AND SWAN FOR SEAS. SHORT TERM: WINDS/SEAS ARE EXPECTED TO BE ABOVE SMALL CRAFT ADVISORY LEVELS SUNDAY NIGHT THROUGH EARLY TUESDAY...WITH SEAS REMAINING ABOVE SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT. SMALL CRAFT ADVISORY CONDITIONS ARE THEN POSSIBLE WEDNESDAY THROUGH THURSDAY. VISIBILITIES WILL BE REDUCED IN SHOWERS MONDAY AFTERNOON THROUGH EARLY TUESDAY...THEN AGAIN TUESDAY NIGHT THROUGH THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SUNDAY FOR ANZ050-051. && $$ NEAR TERM...HEWITT SHORT TERM...NORCROSS LONG TERM...NORTON AVIATION...HEWITT MARINE...HEWITT/NORCROSS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1235 AM EST SAT DEC 13 2008 .SYNOPSIS... HIGH PRESSURE BUILDS IN FROM THE WEST TONIGHT THROUGH SATURDAY. THE HIGH WILL THEN MOVE OFFSHORE ON SUNDAY. A SERIES OF COLD FRONTS AND AREAS OF LOW PRESSURE WILL MOVE THROUGH THE REGION MONDAY THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HI PRES WILL BLD TO JUST W OF THE AREA TNGT. UNDR A CLR OR MSTLY CLR SKY...MIN TEMPS WILL RANGE THRU THE 20S TO LWR 30S. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/... QUIET WX IN STORE FOR THE WKND THRU MON...AS HI PRES WILL BLD ACRS THE REGION ON SAT...THEN SLIDE INTO THE ATLC FOR SUN AND MON. DESPITE A SNY SKY...IT WILL BE CHILLY ON SAT WITH MAX TEMPS RANGING FM THE UPR 30S TO UPR 40S. MSTLY CLR AND COLD SAT NGT WITH MIN TEMPS RANGING FM THE UPR TEENS (SBY) TO THE LWR 30S. TEMPS WILL REBOUND TO NR NORMAL ON SUN...WITH THE HI OFFSHR PROVIDING SE OR S WNDS. UNDR A PRTLY TO MSTLY SNY SKY...MAX TEMPS WILL RANGE FM THE UPR 40S TO MID 50S. MILD CONDS THEN EXPECTED ON MON...DUE TO THE COMBINATION OF HI PRES OVR THE ATLC AND AN APPROACHING FRNT FM THE W PROVIDING SSW WNDS INTO THE REGION. PRTLY SNY WITH MAX TEMPS IN THE LWR TO MID 60S...CUD END UP WRMER. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... BOTH THE 12Z RUNS OF THE GFS AND ECMWF MOVE A SERIES OF LOW PRES SYSTEMS AND ASSOCIATED FRONTAL BOUNDARIES THRU THE REGION MON NIGHT THRU WED NIGHT...AND WILL CARRY CHANCE POPS (25-40%) DURING THAT TIME. DO NOT EXPECT ANYTHING OTHER THAN LIQUID PRECIP WITH TEMPS REMAINING ABOVE FRZ. LOWS WILL BE IN THE MID 40S TO LWR 50S MON NIGHT...THEN NEAR 40 TO NEAR 50 TUE NIGHT. HIGHS IN THE MID 50S TO MID 60S ON BOTH TUE AND WED. BEYOND WED NIGHT THE MODELS START TO DIVERGE WITH THE GFS BRINING ANOTHER LOW UP THRU THE REGION FROM THE SW THRU THE END OF THE WEEK...WHILE THE ECMWF HAS HIGH PRESSURE BUILDING IN BRIEFLY THU THRU FRI. WILL TAKE A MIDDLE OF THE ROAD APPROACH AND FOLLOW CLOSE TO HPC GUIDANCE...ONLY A SLIGHT CHANCE OF RAIN (20%) FOR THE END OF NEXT WEEK. HIGHS THU WILL BE NEAR 50 TO NEAR 60...WITH LOWS IN THE UPR 20S TO UPR 30S THU NIGHT. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... SCT TO BKN SC DECK ARND 5K FT AND SOME GUSTY N-NW WNDS WILL CONT NXT SVRL HRS AS AN UPR LVL TROF CROSSES AREA NXT. XPCT THE STRNGR GUSTS (20-25KTS) ACROSS SERN TAF SITES. OTW...HIGH PRS BLDS INTO RGN THRU MONDAY RESULTING IN ONLY SCT CLDS AND LGHTR WNDS. A SERIES OF FRONTS & LOW PRESSURE SYSTMS WILL BRING SCT SHWRS & PSBL MVFR OR IFR CONDITIONS TUE & WED. && .MARINE... N-NW SURGE CRNTLY ONGOING ERLY THIS AM WITH GUSTS BTWN 25-30 KTS ATTM. RUC KEEPS THESE WNDS GOING FOR SVRL MORE HRS B4 DMNSHG LATER THIS AM. SEAS STILL RANGING BTWN 5-6 FT. THUS...HAVE CONTD SCA ALL AREAS WITH 1 AM UPDATE. XPCT WNDS TO SLOWLY SUBSIDE BLO SCA LVLS AFTR SR. MUCH MORE TRANQUIL BOATING CONDITIONS RETURN THIS WEEKEND AS HIGH PRES MOVES OVERHEAD ON SAT...THEN OFFSHORE ON SUN. THE NEXT CHANCE FOR HEADLINES (MARGINAL SCA`S AT THIS POINT) WOULD OCCUR MON AFTERNOON/NIGHT WITH THE INCREASING S/SW FLOW AHEAD OF THE NEXT COLD FRONT. ANOTHER COLD FRONT IS THEN EXPECTED TO MOVE THRU THE WATERS TUE THRU WED. && .HYDROLOGY... ON AVERAGE...A GENERAL SWATH OF 1 TO 4 INCHES OF RAIN OCCURRED OVER THE REGION FROM THIS PAST SYSTEM (LOCALLY HIGHER AMOUNTS OVER 4 INCHES WERE RECORDED OVER THE MD/VA ERN SHORE). RUNOFF WILL PRODUCE RIVER RISES WELL INTO THE THREE-QUARTER BANKFULL RANGE OVER THE NEXT 24 TO 48 HOURS. AS OF 3PM THE MEHERRIN RIVER LEVEL AT LAWRENCEVILLE WAS 15.23 FT AND RISING. IT IS FORECAST TO CREST TONIGHT AROUND 1AM JUST SHY OF 16 FT...ONE FOOT ABOVE FLOOD STAGE. A FLOOD WARNING IS OUT FOR BRUNSWICK COUNTY. PLEASE REFER TO THE FLWAKQ AND WWW.WEATHER.GOV/AKQ (CLICK ON RIVERS & LAKES AHPS) FOR FURTHER INFORMATION AND UPDATES. $$ && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ630>633-656-658. SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ650- 652-654. && $$ SYNOPSIS...TMG NEAR TERM...TMG SHORT TERM...TMG LONG TERM...JRL AVIATION...MPR MARINE...JRL/MPR HYDROLOGY... md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1205 AM EST SAT DEC 13 2008 .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW POLAR VORTEX IN THE VCNTY OF NW HUDSON BAY. ONE TROF EXTENDS S THRU INTO THE ERN CONUS WHILE ANOTHER TROF EXTENDS SW TO BRITISH COLUMIBA/PACIFIC NW. SHORTWAVE CURRENTLY SLAMMING ONSHORE OVER THE PACIFIC NW WILL BE THE NEXT IMPORTANT FEATURE OF INTEREST FOR THE FCST AREA AS IT DROPS SE AND THEN LIFTS NE INTO THE UPPER LAKES REGION LATE IN THE WEEKEND. AT THE CURRENT TIME...NW FLOW CONTINUES INTO THE GREAT LAKES ON THE BACKSIDE OF THE ERN CONUS TROF. SHORTWAVE OVER SASKATCHEWAN/SRN MANITOBA WILL PASS OVER THE UPPER LAKES TONIGHT BEFORE FLOW BACKS SW AHEAD OF THE SHORTWAVE DROPPING SE INTO THE ROCKIES. && .SHORT TERM (TONIGHT/SAT)... AS SHORTWAVE STREAKS INTO THE UPPER LAKES TONIGHT...FAIRLY STRONG PUSH OF ISENTROPIC ASCENT PER 285K SFC (AROUND 700MB) SPREADS ACROSS THE AREA. 18Z NAM NET ISENTROPIC ADIABATIC OMEGA MATCHES UP WELL WITH WHERE HIGHER RADAR REFLECTIVITIES ARE NOW SHOWING UP IN NRN MN. MIXING RATIOS OF 1-2G/KG ARE AVBL...SUGGESTING 6HR SNOW ACCUMULATIONS OF ROUGHLY 1-2 INCHES. HOWEVER...QUICK MOVEMENT WILL LIMIT AMOUNTS. EXPECT ACCUMULATIONS UNDER 1 INCH ACROSS THE SW PORTION OF THE FCST AREA AND AROUND 1 INCH ACROSS THE N. LOW-LEVEL WINDS MAY HAVE ENOUGH OF A SRLY COMPONENT TO ADD A LITTLE LAKE ENHANCMENT OVER PORTIONS OF SCHOOLCRAFT/LUCE...BUT WINDS A BIT HIGHER UP AROUND 850MB HAVE TOO MUCH OF A WRLY COMPONENT. SO ANY LAKE ENHANCMENT WILL BE MINIMAL. HAVE KEPT ACCUMULATIONS TO NO MORE THAN 2 INCHES IN THAT AREA. MIN TEMPS WILL OCCUR THIS EVENING AND WILL BE AT OR JUST A FEW DEGREES LWR THAN CURRENT TEMPS. EXPECT A STEADY RISING TREND DURING THE NIGHT UNDER THICKENING CLOUDS/WAA AND MOISTURE ADVECTION. WAA/ISENTROPIC ASCENT CONTINUES THRU THE DAY SAT...BUT ASCENT IS LESS FOCUSED THAN WHAT OCCURS TONIGHT. IT SHOULD RESULT IN PERIODIC -SN...BUT PTYPE MAY BECOME AN ISSUE. FCST SOUNDINGS SUGGEST THAT ENOUGH DRYING MAY OCCUR ABOVE THE LOW-LEVELS THAT MOISTURE MAY NO LONGER EXTEND TO THE -10C ISOTHERM. HAVE THUS INCLUDED A SLIGHT CHC MENTION OF -FZDZ EXCEPT IN THE AREAS NEAR LAKE SUPERIOR THAT DOWNSLOPE WITH SRLY WINDS. .LONG TERM (SAT NIGHT THROUGH NEXT FRIDAY)... PERIOD BEGINS WITH DEEPENING TROUGH OVER THE WRN CONUS AND SW FLOW OVER THE CNTRL CONUS. AT THE SFC...BROAD INVERTED TROUGH STRETCHES NE...ACROSS MN...WRN WI...AND WRN LK SUP...FROM 988MB LOW IN THE LEE OF THE ROCKIES. BROAD AREA OF WAA AND ISENTROPIC LIFT ON 280-285K SFC AS SWRLY WINDS INCREASE THROUGH THE NIGHT. EXPECT PCPN ACROSS THE ENTIRE AREA ON SAT NIGHT...WITH BEST CHANCES OVER LK SUP AND ERN HALF OF THE CWA. LK SUP IS UNDER TIGHTENING H850-700 THERMAL GRADIENT ALONG INVERTED TROUGH AND BEST H500-300 Q-VECT CONV...WHILE ERN HALF HAS BEST 280-290K LIFT AND COND PRES DEF. IN ADDITION...EXPECT FAR ERN PART OF CWA TO HAVE SOME LK ENHANCEMENT OFF LK MI WITH MARGINAL DELTA T VALUES...AROUND 8-10C. EXPECT THIS ENHANCEMENT TO MAINLY BE DURING THE THE EVENING HOURS...AS H850 TEMPS GRADUALLY RISE TOWARDS -3C BY 12Z. EXPECT PCPN TO REMAIN SNOW ACROSS MOST OF THE AREA THROUGH THE NIGHT...AS BUFKIT SOUNDINGS KEEP TEMP PROFILE BELOW ZERO. THERE IS A HINT OF SOME MID LEVEL DRY AIR OVER THE CWA BETWEEN PCPN WAVES...WHICH MAY LIMIT ICE IN THE CLOUDS AND PRODUCE SOME FZDZ...BUT LEFT OUT FOR NOW. OTHERWISE....IT LOOKS LIKE RAIN MAY START TO MIX IN WITH THE SNOW ALONG THE LK MI SHORELINE AFTER 06Z...AS WBZ VALUES APPROACH 1.2-1.5KFT. THUS...HAVE CONTINUED THE MENTION OF RAIN IN THOSE AREAS. FOR SUN...THERE HAS BEEN A SLIGHT WNW SHIFT OF THE LOW TRACK ACROSS UPPER MI. 12Z NAM STRONGEST AND FARTHEST NW...AROUND 992MB AND TRACKING IT ACROSS THE KEWEENAW...WHILE 12Z GFS AND 00Z ECMWF SEND THE MID 990S LOW BETWEEN LANSE AND MQT. LATEST 12Z ECMWF CAME IN THIS AFTN AND SHIFTED THE LOW AND COLDER AIR SLIGHTLY TO THE EAST...WITH THE LOW LOCATED AROUND IRON RIVER AT 00Z MON...COMPARED TO MARENISCO/WATERSMEET AREA ON 00Z RUN. LOW TRACK AND WARM AIR WRAPPING AROUND WILL HAVE THE LARGEST EFFECT ON PCPN TYPE OVER FAR WRN UP. LOOKING LIKE MORE OF A MIX OF RAIN/SNOW OVER THE FAR WEST NOW...BASED ON 12Z LOCAL REGWRF AND 12Z NAM BUFKIT SOUNDINGS...AS ISOTHERMAL LAYER AROUND 0C STRETCHES FROM THE SFC TO H800 AT KIWD. 12Z GFS HAS TRENDED A LITTLE WARMER...WITH TEMPS WARMING TO 2-3C BETWEEN SFC AND H800. HAVE DECIDED TO KEEP RAIN/SNOW MIX OVER SW PART OF CWA AND HAVE ADJUSTED DOWN SNOW AMOUNTS IN THAT AREA. KEWEENAW WILL BE ON THE EDGE OF RAIN/SNOW...AS WARM AIR ATTEMPTS TO WRAP UP ON SUN. LATEST LOCAL REGWRF / GFS BUFKIT SOUNDINGS AT CMX HINT AT A LONGER RAIN POSSIBLY MIXED WITH SNOW SITUATION LATE SUN AFTN/EVENING. ALSO CONTINUED MENTION OF FZRA OVER THE W CNTRL PART OF THE CWA SUN MORN. SFC TEMPS WILL BE RIGHT AROUND FREEZING...BUT DO NOT HAVE ENOUGH CONFIDENCE ON SFC TEMPS FOR AMOUNT OF FZRA. WITH TEMPS NEARLY STEADY ON SAT NIGHT AND THEN STRONG SOUTHERLY WINDS BRINGING MORE WARM AIR N...DO NOT SEE ENOUGH COLD AIR AT THE SFC TO HAVE WIDESPREAD FZRA...EVEN THOUGH SNOW COVER AND RECENT COLD TEMPS HAVE GROUND TEMPS JUST BELOW FREEZING. WILL NEED TO CONTINUE TO FINE TUNE PCPN TYPE WITH FUTURE SHIFTS. STILL EXPECTING A FAIRLY STRONG AREA OF PCPN TO MOVE FROM S TO N ACROSS THE CWA ON SUN MORN INTO EARLY AFTN...AS LEFT EXIT REGION OF 130KT JET PUSHES INTO NRN WI AND PWAT VALUES PEAK AROUND 0.6-0.8IN. STRONG MID LVL LAPSE RATES ASSOCIATED WITH THIS...AROUND 7C/KM BETWEEN H700-500 MAY BE ENOUGH TO GENERATE A FEW RUMBLES OF THUNDER. SHOWALTERS ARE STILL MARGINAL...2C...SO CONTINUED TO LEAVE OUT THUNDER. NO HEADLINES AT THIS TIME...BUT THINKING THAT ADVISORIES MAY BE NEEDED AT SOME POINT ALONG THE WRN TIER OF COUNTIES...DUE TO A FEW INCHES OF SNOW AND THE MIX OF PCPN AT TIME...MAKING ROADS A LITTLE SLICK. MADE SOME ADJUSTMENTS TO THE POPS ON SUN NIGHT...AS DRIER AIR MOVES IN BEHIND THE COLD FRONT AND THE LES STARTS TO KICK IN. BIGGEST ITEM OF NOTE IS THE RAPID DROP IN TEMPS EXPECTED FROM W TO E ACROSS THE CWA. AFTER THE NEARLY STEADY TEMPS ON SUN...EXPECT TEMPS OVER THE W TO DROP FROM AROUND FREEZING TO THE SINGLE DIGITS ABOVE ZERO BY DAYBREAK MON. THE CNTRL CWA WILL ALSO SEE A DROP...BUT NOT AS SUBSTANTIAL AS THE W...WHILE THE E IS NOT EXPECTED TO DROP MUCH UNTIL MON. THIS SHOULD RAPIDLY FREEZE ANY WATER/MOISTURE ON THE ROADWAYS AND MAKE FOR A VERY DIFFICULT TRAVEL PERIOD SUN NIGHT INTO MON. EXPECT A GRADUAL DROP IN TEMPS THROUGH THE DAY ON MON...WITH THE DAYS HIGHS OCCURRING AROUND DAYBREAK. LES WILL DEVELOP OVER THE W ON SUN NIGHT AND CONTINUE INTO TUES...AS H850 TEMPS DROP INTO THE LOW -20S. WITH A WNW WIND...EXPECT THE TRADITIONAL LES AREAS OVER THE WEST AND NEAR LK SUP E OF MQT TO SEE THE MOST SNOW. STRONG WINDS ON MON SHOULD CAUSE SOME BLOWING AND DRIFTING OF THE SNOW OVER THE W...ESPECIALLY ALONG THE LK SUP SHORELINE. KEWEENAW SHOULD SEE THE STRONGEST WINDS ON MON...WITH GUSTS TOWARDS 40MPH...AS THE LOW EXITS AND PRESS RISE/FALL COUPLET MOVES THROUGH. DO NOT EXPECT MUCH LES ACCUMULATION OVER THE W...WITH MOST OF THE SNOW BEING PLATE/COLUMN TYPE...AS DGZ DROPS TO THE SFC WITH THE CAA AND STRONG WINDS BREAK UP ANY OF THE LARGER FLAKES. ;ES WILL START TO SHIFT OVER LK SUP ON MON NIGHT AND TUES...AS WINDS BACK TO THE SW AHEAD OF A HIGH SLIDING OUT OF THE PLAINS. MODERATE CONFIDENCE IN THE FORECAST PAST DAY 4...AS MODELS HAVE SOME DIFFERENCES IN THEIR UPR LVL AND SFC SOLNS. BOTH 00Z GFS/ECMWF SHOWING SHORTWAVE MOVING THROUGH THE FLOW AND ACROSS THE CWA SOMETIME ON TUES NIGHT OR WED...WHICH DEVELOPS A LOW OVER THE SRN GREAT LKS OR OHIO VALLEY. HAVE CONTINUED LOW CHANCE POPS DURING THAT TIME PERIOD FOR THE PASSAGE OF THE WAVE. BEHIND THE WAVE...HIGH PRESS EXPECTED OVER THE PLAINS...WHICH WILL GIVE US NW FLOW OFF LK SUP. WITH H850 TEMPS IN THE LOW -20C RANGE...HAVE CHANCE POPS IN TRADITIONAL NW WIND LES LOCATIONS FOR WED NIGHT THROUGH THURS NIGHT. WINDS BEGIN TO BACK A LITTLE MORE WRLY ON FRI...SO HAVE TRANSITIONED POPS TO BE MAINLY OVER W AND KEWEENAW. OVERALL...TEMPS WILL BE BELOW NORMAL THROUGH THE WEEK...WITH HIGHS IN THE TEENS AND SOME MODERATION TOWARDS THE END OF THE WEEK. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... AT KCMX...IFR CONDITIONS ARE EXPECTED WITH -SN AS MOISTURE AND WARMER AIR STREAM NE INTO THE UPPER LAKES IN CONJUNCTION WITH A DISTURBANCE THROUGH THE REST OF THE NIGHT. AFTER PASSAGE OF DISTURBANCE...MVFR CONDITIONS SHOULD PREVAIL AT KCMX SAT MORNING UNDER CONTINUED ADVECTION OF WARMER/MOIST AIR. IN THE AFTERNOON...LOWER CIGS AND VIS WILL BE COMING IN WITH A LOWER STRATUS DECK AND POSSIBLY SOME FOG WITH THIS AS WELL AS WAA OUT AHEAD OF NEXT WAVE WITH LIGHT SNOW MOVES IN. DOWNSLOPE COMES INTO PLAY WITH A SOUTHEAST WIND IN THE EVENING...SO CONDITIONS COULD GO BACK TO MVFR AT KCMX WITH A SE WIND CAUSED BY DOWNSLOPE OFF THE HURON MOUNTAINS. AT KSAW...CONDITIONS WILL FALL TO IFR AS -SN DEVELOPS WITH PASSING DISTURBANCE. UNDER CONTINUED ADVECTION OF WARMER/MOIST AIR...MVFR CONDITIONS EXPECTED SAT MORNING AFTER -SN ENDS. ALSO...INCREASING LOW-LEVEL JET SHOULD RESULT IN LLWS OVERNIGHT THRU MID MORNING SAT. IN THE AFTERNOON...LOWER CIGS AND VIS WILL BE COMING IN WITH A LOWER STRATUS DECK AND POSSIBLY SOME FOG WITH THIS AS WELL AS WAA OUT AHEAD OF NEXT WAVE WITH LIGHT SNOW MOVES IN. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SRLY WINDS WILL INCREASE TO 20-30KT ACROSS LAKE SUPERIOR TONIGHT AS HIGH PRES RIDGE MOVES E OF THE AREA. STRONGEST WINDS WILL OCCUR OVER ERN LAKE SUPERIOR WHERE A FEW GUSTS MAY APPROACH GALE FORCE LATE TONIGHT/EARLY SAT. WINDS WILL THEN DIMINISH SOME SAT AS PRES GRADIENT SLACKENS...ESPECIALLY OVER WRN LAKE SUPERIOR. LOW PRES WILL THEN TRACK NE...CROSSING LAKE SUPERIOR SUN NIGHT. AHEAD OF THE LOW...SRLY WINDS WILL RAMP UP TO 20-30KT SAT NIGHT OVER ERN LAKE SUPERIOR. INCREASE IN WINDS WILL HOLD OFF OVER WRN LAKE SUPERIOR UNTIL SUN WHEN NE WINDS WILL INCREASE TO GALE FORCE ON THE BACKSIDE OF A SW-NE ORIENTED TROF BISECTING THE LAKE. LOW WILL TRACK ALONG THE TROF SUN NIGHT. IN THE WAKE OF THE LOW...EXPECT GALE FORCE W TO NW WINDS ACROSS MOST OF LAKE SUPERIOR LATE SUN NIGHT/MON UNDER INTENSE CAA REGIME. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN... GALE WARNING 5 AM SAT TO 1 PM EST MON LMZ248-250. GALE WATCH SUN AFTN THRU MON AFTN LMZ221. && $$ SYNOPSIS/SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...GM MARINE...ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 410 PM CST SUN DEC 14 2008 .DISCUSSION... NO CHANGES TO ANY HEADLINES ATTM. AT 4 PM...THE SFC LOW WAS SE OF SIREN...WITH NORTHWEST WINDS AND 12 DEGREES AT MOOSE LAKE...AND 41 DEGREES AND A SOUTH WIND AT LADYSMITH. HEAVY SNOW AND WIDESPREAD HALF MILE OR LESS VISIBILITIES WILL PERSIST THROUGH THE EVENING...GRADUALLY IMPROVING AFTER MIDNIGHT. HOWEVER...MUCH COLDER AIR WILL BLAST INTO THE REGION OVERNIGHT AND THE COMBINATION OF WIND AND COLD FOR MOST AREAS THROUGH NOON ON MONDAY. AS SFC LOW PUSHES INTO NRN WIS...TRANSITIONS ZONE HAS PIVOTED NOW INTO THE SE ZONES...GENERALLY FROM ASKOV IN PINE COUNTY...TO HAYWARD...AND NE HURLEY. THE SFC LOW HAS TAKEN A SLIGHTLY FURTHER WEST TRACK THAN PREV ANTICIPATED. THIS HAS ALLOWED THE RA/FZRA ZONE TO SHIFT SLIGHTLY FURTHER WEST...INTO PINE COUNTY. THE FREEZING PCPN WILL CHANGE OVER TO ALL SN FROM WEST TO EAST THROUGH 8 PM...AS WINDS SWITCH TO THE NW AND TEMPERATURES DRASTICALLY FALL 15-20 DEGREES F IN A VERY SHORT TIME. AS WINDS SHIFT TO THE NORTHWEST THIS EVENING... IT IS LIKELY THAT BLIZZARD CONDITIONS WILL SUBSIDE INT THE TWIN PORTS REGION. HOWEVER...WINDS TO 30 MPH OR HIGHER WILL BE POSSIBLE THROUGH THE NIGHT...ALLOWING FOR BLOWING AND DRIFTING SNOW TO PERSIST INTO MONDAY MORNING. INCREASED POPS AND SN AMOUNTS ALONG SOUTH SHORE OF LAKE SUPERIOR ON MONDAY WHERE FAVORABLE LAPSE RATES AND TRAJECTORIES IS EXPECTED TO BRING ANOTHER 3 TO 6 INCHES TO THE SNOW BELT REGION OF NORTHERN WISCONSIN. && .PREV DISCUSSION... /ISSUED 151 PM CST SUN DEC 14 2008/ UPDATE... CURRENT RADAR IMAGERY SHOWS A LARGE SWATH OF +SN OVER THE NRN HALF OF MN. MOST SNOWFALL OBSERVERS IN NE MN ARE REPORTING 5-7 INCHES OF SN ACCUMULATIONS AS OF 1 PM WITH +SN CONTINUING. SEVERAL SPOTTERS IN THE HEAVIER BANDS HAVE MEASURED 1.5-2 INCHES PER HR RATES. THE GREATEST STORM TOTAL ATTM...IS 9 INCHES IN WEST DULUTH. THE STRONG WINDS AND DRIFTING ARE PROVING TO MAKE ACCURATE SNOWFALL MEASUREMENTS DIFFICULT. A VERY STRONG BAROCLINIC ZONE IS DEPICTED IN THE 19Z SFC OBS. TEMPS RANGING FROM 8F BELOW ZERO AT BAUDETTE MN...18F ABOVE ZERO AT THE DULUTH AP...AND 36F WITH RA AT PHILLIPS WI. THE TIGHT PRESSURE GRADIENT HAS ALSO RESULTED IN STRONG WINDS WITH MOST LOCATIONS IN NRN MN GUSTING AROUND 30KT. THE WX STATIONS AT KDYT/DULM5 CONTINUE TO REPORT A SUSTAINED 30-35 KT WIND WITH GUSTS AROUND 45 KT. WIDESPREAD WHITE OUT CONDITIONS WITH VSBYS OF 1/4SM OR LESS PERSIST IN THE TWIN PORTS REGION. TURNING TO RA/SN TRANSITION ZONE IN NW WIS. THE ASOS AT KHYR IS CURRENTLY REPORTING 30F AND FZRA...WHILE JUST TO THE ESE AT KPBH THE SFC STATION IS REPORTING 36F AND RA. THIS LINES UP WELL WITH THE CURRENT FCST SO NO SIG CHANGES MADE. THIS ZONE WILL SLOWLY SHIFT EAST AS IT PIVOTS BACK TO THE NW...AND IS NOT EXPECTED TO BUILD FURTHER W. ONCE WINDS BACK TO THE N THEN NW...STRONG CAA WITH A 30KT LLJ WILL COOL THE COLUMN QUICKLY FOR ALL SN. PREV DISCUSSION... /ISSUED 950 AM CST SUN DEC 14 2008/ UPDATE... INCREASED WINDS/GUSTS IN FCST TODAY TO BETTER REFLECT CURRENT OBSERVATIONS. FOR PAST SEVERAL HRS KDYT AND DULM5 HAVE BEEN SUSTAINED AROUND 30 KT...WITH GUSTS AROUND 40 KTS. AT 1530Z KDYT HAD A GUST TO 45 KT. EXPECTED THESE WINDS TO PERSIST...OR BECOME STRONGER THROUGH THE AFTERNOON AS THE SFC LOW MOVES INTO NRN WIS. UP T0 60 MPH WILL BE POSSIBLE AT THE HEAD OF LAKE SUPERIOR IN THE DULUTH/SUPERIOR HARBOR THIS AFTERNOON. AREA OF +SN AND 1/2SM OR LESS VSBY CONTINUING GOOD PACE LIFTING NWRD...WITH LEADING EDGE ON TRACK TO REACH THE TWIN PORTS IN THE NEXT 30 MIN. WATCHING SOUTH SHORE ZONES FOR A POSSIBLE UPGRADE TO BLIZZARD WARNING. THE SFC OBSERVATIONS ARE ONLY GUSTING AROUND 25KT...BUT WILL KEEP IN CONTACT WITH LOCAL LAW ENFORCEMENT IN BAYFIELD/ASHLAND/IRON COUNTIES IN CASE WHITE OUT CONDITIONS BECOME WIDESPREAD. ALSO KEEPING CLOSE WATCH ON RA/SN TRANSITION ZONE THAT IS CURRENTLY SET UP ALONG THE DLH/MPX CWA BORDER IN NRN WISCONSIN. LATEST SFC OBS ARE REPORTING RA FROM OSCEOLA...TO RICE LAKE AND LADYSMITH...AND JUST SN JUST TO THE NORTH FROM CAMBRIDGE...TO SIREN...AND PHILLIPS. PREV DISCUSSION... WELL ADVERTISED SYSTEM BEHAVING AS EXPECTED WITH ONE EXCEPTION. DOME OF COLD AIR IN SFC/85H LAYER HAS MAINTAINED ITSELF ACROSS NW WIS EARLY THIS MORNING. ANIMATION OF RUC13 THERMAL/WIND FIELDS IN BDRY LAYER INDICATE THAT COLDER AIR IS UNDERCUTTING SOUTHWEST FLOW ALOFT. 925H WINDS HAVE SHIFTED FROM SOUTH TO EAST ALONG A RZN TO HYR TO PBH LINE. THIS HAS PUSHED MAIN CONVERGENCE ZONE IN LOW LEVELS FARTHER SOUTH TO ERN PART OF MPX CWA. BAYFIELD PENINSULA APPEARS TO BE EXPERIENCING ENHANCED PRECIP FROM LONG TRAJECTORY DOWN LAKE SUPERIOR. LATEST MSAS SHOWS WELL DEFINED SFC INVERTED TROUGH FROM LOW OVER ERN NEB TO EAX TO HOUGHTON IN UP OF MI. 3HR PRESSRR OVER SERN PART OF CWA CURRENTLY. LATEST SAT IMAGERY SHOWS LARGE AREA OF COOLING CLOUD TOPS ACROSS ERN DAKOTAS IN VICINITY OF DIVERGENCE ASSOCIATED WITH UPPER TROF. STRONG UPPER JETS POISED OVER ONTARIO... WITH NRN BRANCH... AND LEFT EXIT REGION OF SRN PLAINS JET TRANSLATING NE INTO SRN MN/WI. TODAY/TONIGHT...ONLY SIGNIFICANT CHANGE TO EXISTING FCST WAS TO UPGRADE BURNETT/WASHBURN/SAWYER COUNTIES TO WSW. THIS IS PRIMARILY BECAUSE EXISTING THERMAL BDRY IN LOW LAYERS AND UNDERCUTTING OF COLD AIR SHOULD ENSURE MOSTLY SNOW FOR THE MAJORITY OF THE STORM. FSCT SNDGS ALSO REFLECT THIS CHANGE FROM YESTERDAY. BLIZZARD CONDITIONS STILL EXPECTED TODAY ALONG HEAD OF LAKE AS FUNNELING OF HIGHER SPEED AIR OCCURS. DYT ALREADY GUSTING TO ABOUT 40MPH. MAJOR FORCING FACTORS STILL IN PLAY. A LARGE AREA OF MDT/STRONG FRONTOGENESIS WILL BE ENHANCED AS UPPER TROF ADVECTS EAST TODAY. COUPLED JETS WILL ADD TO SYNOPTIC SCALE ASCENT. SOME MIX OF SN/IP/FZRA ACROSS EXTREME ERN CWA AS SFC LOW GETS CLOSER THIS AFTERNOON. WITH COLD AIR ALREADY IN PLACE AND SATURATION OCCURING IN DEEP LAYER SUSPECT THAT POPTYP MAY BE MORE A WET SNOW OR SLEET VS COLD RAIN IN THIS AREA. WINDCHILL VALUES APPROACH/EXCEED ADVISORY CATEGORY TONIGHT BUT DID NOT WANT TO ADD ANOTHER ADVISORY TO BUSY SLATE. WILL VERBALIZE THE THREAT IN THE WSW AND HWO PRODUCTS. TEMPERATURES WILL DROP BELOW ZERO OVER MOST OF THE REGION TONIGHT AND REMAIN BELOW ZERO PERHAPS UNTIL WEDNESDAY AFTERNOON. PLENTY OF BLOWING SNOW EXPECTED AS GUSTY WINDS PUSH FLUFFY LOW DENSITY FLAKES ALL OVER THE PLACE. MONDAY...STORM LOOSENS ITS GRIP BY MONDAY AFTERNOON OVER CWA. SN/BS STILL EXPECTED THROUGH MORNING MOST AREAS. WITH 85/70H RH STILL ABOVE 60 PERCENT MOST OF DAY...SHOULD SEE ADDITIONAL SNOW FOR SNOWBELT WITH VERY HIGH SNOW/LIQUID RATIOS. MAY NEED TO EXTEND WARNING IN THAT AREA. EXTENDED....TUE THRU SAT... SEVERAL S/WVS WILL TRANSIT THE REGION...REQUIRING AT LEAST SOME LOW POPS. THE DRY ARCTIC AIR THAT WILL BE IN PLACE WILL LIMIT ANY POTENTIAL PRECIP. THE MOST LIKELY DRY PD WILL BE WED/THU UNDER WK RIDGING ALOFT...ALTHO SRN ZONES MAY RECEIVE SOME PRECIP BEING ON THE NRN FRINGES OF A SFC SYSTEM MOVG UP THE OH VLY. BOTH GFS AND ECMWF SHOW THIS SYSTEM...ALTHO THERE ARE TIMING DIFFS. AVIATION... GENERALLY IFR/LIFR CONDS IN SN/FG/BLSN WILL PERSIST THRU THE TAF PD AS MAJ WINT STORM MOVES FROM NEB TO LK SUP BY MON MRNG. AT THAT TIME CONDS WILL BEGIN TO GRADUALLY IMPROVE AS THE STORM MOVES AWAY. STRONG NE WINDS WILL SIFT TO THE NW AS THE STORM PASSES...THEN GRADUALLY DIMINISH DURING THE DAY ON MON. && POINT TEMPS/POPS... DLH -10 -5 -25 -7 / 100 30 10 20 INL -11 -6 -33 -9 / 100 30 10 10 BRD -9 -4 -25 -3 / 100 20 10 30 HYR -4 1 -25 -1 / 80 30 10 30 ASX -2 3 -20 0 / 90 60 10 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR CENTRAL ST. LOUIS-KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR CARLTON/SOUTHERN ST. LOUIS. WI...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR BURNETT-SAWYER- WASHBURN. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR ASHLAND-BAYFIELD- IRON. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR DOUGLAS. WINTER WEATHER ADVISORY UNTIL 4 AM CST MONDAY FOR PRICE. LS...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 10 AM CST TUESDAY FOR LSZ121-LSZ146-LSZ147-LSZ148. GALE WARNING UNTIL 4 AM CST MONDAY FOR LSZ121-LSZ144-LSZ145- LSZ146-LSZ147-LSZ148. SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM CST TUESDAY FOR LSZ144-LSZ145. SMALL CRAFT ADVISORY UNTIL 4 AM CST TUESDAY FOR LSZ140-LSZ141- LSZ142-LSZ143. $$ GRANING/EOM mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 151 PM CST SUN DEC 14 2008 .UPDATE... CURRENT RADAR IMAGERY SHOWS A LARGE SWATH OF +SN OVER THE NRN HALF OF MN. MOST SNOWFALL OBSERVERS IN NE MN ARE REPORTING 5-7 INCHES OF SN ACCUMULATIONS AS OF 1 PM WITH +SN CONTINUING. SEVERAL SPOTTERS IN THE HEAVIER BANDS HAVE MEASURED 1.5-2 INCHES PER HR RATES. THE GREATEST STORM TOTAL ATTM...IS 9 INCHES IN WEST DULUTH. THE STRONG WINDS AND DRIFTING ARE PROVING TO MAKE ACCURATE SNOWFALL MEASUREMENTS DIFFICULT. A VERY STRONG BAROCLINIC ZONE IS DEPICTED IN THE 19Z SFC OBS. TEMPS RANGING FROM 8F BELOW ZERO AT BAUDETTE MN...18F ABOVE ZERO AT THE DULUTH AP...AND 36F WITH RA AT PHILLIPS WI. THE TIGHT PRESSURE GRADIENT HAS ALSO RESULTED IN STRONG WINDS WITH MOST LOCATIONS IN NRN MN GUSTING AROUND 30KT. THE WX STATIONS AT KDYT/DULM5 CONTINUE TO REPORT A SUSTAINED 30-35 KT WIND WITH GUSTS AROUND 45 KT. WIDESPREAD WHITE OUT CONDITIONS WITH VSBYS OF 1/4SM OR LESS PERSIST IN THE TWIN PORTS REGION. TURNING TO RA/SN TRANSITION ZONE IN NW WIS. THE ASOS AT KHYR IS CURRENTLY REPORTING 30F AND FZRA...WHILE JUST TO THE ESE AT KPBH THE SFC STATION IS REPORTING 36F AND RA. THIS LINES UP WELL WITH THE CURRENT FCST SO NO SIG CHANGES MADE. THIS ZONE WILL SLOWLY SHIFT EAST AS IT PIVOTS BACK TO THE NW...AND IS NOT EXPECTED TO BUILD FURTHER W. ONCE WINDS BACK TO THE N THEN NW...STRONG CAA WITH A 30KT LLJ WILL COOL THE COLUMN QUICKLY FOR ALL SN. && .PREV DISCUSSION... /ISSUED 950 AM CST SUN DEC 14 2008/ UPDATE... INCREASED WINDS/GUSTS IN FCST TODAY TO BETTER REFLECT CURRENT OBSERVATIONS. FOR PAST SEVERAL HRS KDYT AND DULM5 HAVE BEEN SUSTAINED AROUND 30 KT...WITH GUSTS AROUND 40 KTS. AT 1530Z KDYT HAD A GUST TO 45 KT. EXPECTED THESE WINDS TO PERSIST...OR BECOME STRONGER THROUGH THE AFTERNOON AS THE SFC LOW MOVES INTO NRN WIS. UP T0 60 MPH WILL BE POSSIBLE AT THE HEAD OF LAKE SUPERIOR IN THE DULUTH/SUPERIOR HARBOR THIS AFTERNOON. AREA OF +SN AND 1/2SM OR LESS VSBY CONTINUING GOOD PACE LIFTING NWRD...WITH LEADING EDGE ON TRACK TO REACH THE TWIN PORTS IN THE NEXT 30 MIN. WATCHING SOUTH SHORE ZONES FOR A POSSIBLE UPGRADE TO BLIZZARD WARNING. THE SFC OBSERVATIONS ARE ONLY GUSTING AROUND 25KT...BUT WILL KEEP IN CONTACT WITH LOCAL LAW ENFORCEMENT IN BAYFIELD/ASHLAND/IRON COUNTIES IN CASE WHITE OUT CONDITIONS BECOME WIDESPREAD. ALSO KEEPING CLOSE WATCH ON RA/SN TRANSITION ZONE THAT IS CURRENTLY SET UP ALONG THE DLH/MPX CWA BORDER IN NRN WISCONSIN. LATEST SFC OBS ARE REPORTING RA FROM OSCEOLA...TO RICE LAKE AND LADYSMITH...AND JUST SN JUST TO THE NORTH FROM CAMBRIDGE...TO SIREN...AND PHILLIPS. PREV DISCUSSION... WELL ADVERTISED SYSTEM BEHAVING AS EXPECTED WITH ONE EXCEPTION. DOME OF COLD AIR IN SFC/85H LAYER HAS MAINTAINED ITSELF ACROSS NW WIS EARLY THIS MORNING. ANIMATION OF RUC13 THERMAL/WIND FIELDS IN BDRY LAYER INDICATE THAT COLDER AIR IS UNDERCUTTING SOUTHWEST FLOW ALOFT. 925H WINDS HAVE SHIFTED FROM SOUTH TO EAST ALONG A RZN TO HYR TO PBH LINE. THIS HAS PUSHED MAIN CONVERGENCE ZONE IN LOW LEVELS FARTHER SOUTH TO ERN PART OF MPX CWA. BAYFIELD PENINSULA APPEARS TO BE EXPERIENCING ENHANCED PRECIP FROM LONG TRAJECTORY DOWN LAKE SUPERIOR. LATEST MSAS SHOWS WELL DEFINED SFC INVERTED TROUGH FROM LOW OVER ERN NEB TO EAX TO HOUGHTON IN UP OF MI. 3HR PRESSRR OVER SERN PART OF CWA CURRENTLY. LATEST SAT IMAGERY SHOWS LARGE AREA OF COOLING CLOUD TOPS ACROSS ERN DAKOTAS IN VICINITY OF DIVERGENCE ASSOCIATED WITH UPPER TROF. STRONG UPPER JETS POISED OVER ONTARIO... WITH NRN BRANCH... AND LEFT EXIT REGION OF SRN PLAINS JET TRANSLATING NE INTO SRN MN/WI. TODAY/TONIGHT...ONLY SIGNIFICANT CHANGE TO EXISTING FCST WAS TO UPGRADE BURNETT/WASHBURN/SAWYER COUNTIES TO WSW. THIS IS PRIMARILY BECAUSE EXISTING THERMAL BDRY IN LOW LAYERS AND UNDERCUTTING OF COLD AIR SHOULD ENSURE MOSTLY SNOW FOR THE MAJORITY OF THE STORM. FSCT SNDGS ALSO REFLECT THIS CHANGE FROM YESTERDAY. BLIZZARD CONDITIONS STILL EXPECTED TODAY ALONG HEAD OF LAKE AS FUNNELING OF HIGHER SPEED AIR OCCURS. DYT ALREADY GUSTING TO ABOUT 40MPH. MAJOR FORCING FACTORS STILL IN PLAY. A LARGE AREA OF MDT/STRONG FRONTOGENESIS WILL BE ENHANCED AS UPPER TROF ADVECTS EAST TODAY. COUPLED JETS WILL ADD TO SYNOPTIC SCALE ASCENT. SOME MIX OF SN/IP/FZRA ACROSS EXTREME ERN CWA AS SFC LOW GETS CLOSER THIS AFTERNOON. WITH COLD AIR ALREADY IN PLACE AND SATURATION OCCURING IN DEEP LAYER SUSPECT THAT POPTYP MAY BE MORE A WET SNOW OR SLEET VS COLD RAIN IN THIS AREA. WINDCHILL VALUES APPROACH/EXCEED ADVISORY CATEGORY TONIGHT BUT DID NOT WANT TO ADD ANOTHER ADVISORY TO BUSY SLATE. WILL VERBALIZE THE THREAT IN THE WSW AND HWO PRODUCTS. TEMPERATURES WILL DROP BELOW ZERO OVER MOST OF THE REGION TONIGHT AND REMAIN BELOW ZERO PERHAPS UNTIL WEDNESDAY AFTERNOON. PLENTY OF BLOWING SNOW EXPECTED AS GUSTY WINDS PUSH FLUFFY LOW DENSITY FLAKES ALL OVER THE PLACE. MONDAY...STORM LOOSENS ITS GRIP BY MONDAY AFTERNOON OVER CWA. SN/BS STILL EXPECTED THROUGH MORNING MOST AREAS. WITH 85/70H RH STILL ABOVE 60 PERCENT MOST OF DAY...SHOULD SEE ADDITIONAL SNOW FOR SNOWBELT WITH VERY HIGH SNOW/LIQUID RATIOS. MAY NEED TO EXTEND WARNING IN THAT AREA. EXTENDED....TUE THRU SAT... SEVERAL S/WVS WILL TRANSIT THE REGION...REQUIRING AT LEAST SOME LOW POPS. THE DRY ARCTIC AIR THAT WILL BE IN PLACE WILL LIMIT ANY POTENTIAL PRECIP. THE MOST LIKELY DRY PD WILL BE WED/THU UNDER WK RIDGING ALOFT...ALTHO SRN ZONES MAY RECEIVE SOME PRECIP BEING ON THE NRN FRINGES OF A SFC SYSTEM MOVG UP THE OH VLY. BOTH GFS AND ECMWF SHOW THIS SYSTEM...ALTHO THERE ARE TIMING DIFFS. AVIATION... GENERALLY IFR/LIFR CONDS IN SN/FG/BLSN WILL PERSIST THRU THE TAF PD AS MAJ WINT STORM MOVES FROM NEB TO LK SUP BY MON MRNG. AT THAT TIME CONDS WILL BEGIN TO GRADUALLY IMPROVE AS THE STORM MOVES AWAY. STRONG NE WINDS WILL SIFT TO THE NW AS THE STORM PASSES...THEN GRADUALLY DIMINISH DURING THE DAY ON MON. && POINT TEMPS/POPS... DLH -10 -5 -21 0 / 80 40 10 20 INL -11 -6 -28 -5 / 80 40 10 20 BRD -9 -4 -18 1 / 80 20 10 20 HYR -4 1 -19 2 / 80 30 10 20 ASX -2 3 -14 5 / 80 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR CENTRAL ST. LOUIS-KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR CARLTON/SOUTHERN ST. LOUIS. WI...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR BURNETT-SAWYER- WASHBURN. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR ASHLAND-BAYFIELD- IRON. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR DOUGLAS. WINTER WEATHER ADVISORY UNTIL 4 AM CST MONDAY FOR PRICE. LS...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM CST TUESDAY FOR LSZ121-LSZ146-LSZ147-LSZ148. GALE WARNING UNTIL 4 AM CST MONDAY FOR LSZ121-LSZ144-LSZ145- LSZ146-LSZ147-LSZ148. SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM CST MONDAY FOR LSZ144- LSZ145. SMALL CRAFT ADVISORY UNTIL 4 PM CST MONDAY FOR LSZ140-LSZ141- LSZ142-LSZ143. $$ GRANING/EOM mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1218 PM CST SUN DEC 14 2008 .AVIATION.../18Z TAF ISSUANCE/ NOT MUCH CHANGE FROM PREVIOUS FORECAST EXPECTATIONS THROUGH THE PERIOD. SURFACE LOW IS CURRENTLY IN THE VICINITY OF KMSP AND WILL LIFT NORTHEAST THROUGH THE AFTERNOON. COLD AIR HAS WRAPPED AROUND THE WESTERN AND SOUTHERN SIDES OF THE LOW... CHANGES PCPN TO SNOW IN MOST OF THAT AREA. NEAR AND EAST OF THE LOW TEMPERATURES REMAIN ABOVE FREEZING... HOWEVER AS COLD AIR ARRIVES NEAR AND SOUTH OF THE LOW THERE WILL BE A WINDOW OF OPPORTUNITY FOR SOME LIGHT FREEZING PRECIPITATION DUE TO DRIER AIR ALOFT AND THE PRESENCE OF SUPERCOOLED DROPS IN THE LOW LEVELS. IN GENERAL... THESE CONDITIONS WILL GIVE WAY TO AN INCREASE IN DEEP LAYER MOISTURE OVER THE ENTIRE AREA BY THIS EVENING... WITH ANY PCPN EXPECTED TO BE IN THE FORM OF SNOW AT ALL LOCATIONS... WITH KMSP... KRNH... AND KEAU BEING THE ONLY SITES WITH ANY REAL PCPN TYPE ISSUES FROM 18Z THROUGH 00Z. VISIBILITIES WILL BE EXTREMELY LOW OVER THE WEST WHERE FALLING AND BLOWING SNOW WILL HOLD THEM BELOW 1/2 MILE AND BELOW 1/4 MILE AT TIMES. ELSEWHERE... VISIBILITIES WILL GENERALLY VARY FROM IFR TO MVFR THROUGH THE EVENING. CEILINGS ACROSS THE AREA WILL BE IFR FOR MOST OF THE PERIOD... IMPROVING TO MVFR OVERNIGHT... BUT WITH SOME PERIODS OF LIFR THIS AFTERNOON. WINDS WILL BE QUITE STRONG ON THE BACKSIDE OF THE SURFACE LOW... SUSTAINED NEAR 20KT AND GUSTING ABOVE 30KT FOR MUCH OF THE NIGHT... BEFORE WINDING DOWN ON MONDAY. THANKS TO CWSU ZMP FOR COLLABORATION ON KMSP CONDITIONS... THEIR FORECAST THOUGHTS ARE INCLUDED BELOW. INPUT FROM CWSU ZMP... CURRENTLY WE HAVE A LOW OVR NE IA... A WRM AND QS FNT N OF MSP AND THRU THE U.P. MICH... AND A COLD FNT DOWN OVR ERN NE. LOW IS XPCTD TO DEEPEN AS IT MOVS THRU SE MN... INCRSG THE SFC PRES GRAD... AND THEN BEGIN TO OCLD AS LOW MOVS OVR THE U.P. AT THE 24-HR POINT. LOCAL SFC TEMPS ARE XPCTD TO DROP AT A RATE OF 5 F DEGREES PER HR WITH PASSAGE OF COLD FNT AFT 12Z. WITH ATMOS COLUMN DROPPING ENTIRELY BLO FZG BY 20Z... PCPN WILL TURN OVR TO SN. ALTHOUGH THE MDLS ARE LESS DIVERGENT IN THEIR SOLUTIONS TODAY... ONCE AGAIN NO ONE MDL SEEMS TO HAVE ALL THE ANSWERS. I BELIEVE MM5 IS BETTER HANDLING THE CLDS... WHILE NAM HAS A MORE REASONABLE PCPN OUTLOOK. I`D START THE CLDS AT BKN005 OVC010... DROPPING TO OVC005 FROM 21Z THRU 01Z. AFTER THAT THE CIGS RISE TO 015 THRU 06Z... THEN 025 THRU 18Z. THE MM5 WOULD LEAD ONE TO XPCT CIGS NEAR THE SFC TOMMOROW AM... BUT THE GUSTY SFC WNDS AND LOWERING BNDRY LYR ABSOLUTE HUM CONVINCE ME THAT THAT WON/T HAPPEN. I/M FINE WITH THE VIS TREND AS FCSTD IN THE 18Z TAF. THE LOWERING VIS TONIGHT ARE MORE A RESULT OF GUSTY WNDS BLOWING THE SN AROUND THAN THE ACTUAL SN RATE; NO MDL SEEMS TO ACCOUNT FOR BLSN. I ALSO AGREE WITH ENDING THE SN BY 12Z. THE WNDS ARE ALMOST A STRAIGHT-FORWARD FCST COMPARED TO EVERYTHING ELSE. FROPA SHOULD OCCUR RIGHT AT TAF TIME... SWITCHING THE DIR TO 290-300. STEADY SPDS COULD BE ABV 20KT BY 21Z... RISING TO 24KT BY 06Z. AFT 06Z SPDS DROP STEADILY TO 10KT BY 00Z AND 5KT BY END OF TAF. && .PREV DISCUSSION... /ISSUED 930 AM CST SUN DEC 14 2008/ LATEST RADAR IMAGERY SHOWS BAND OF PCPN LIFTING NORTH AND BEGINNING TO PIVOT OVER THE AREA. PCPN TYPE GOES FROM RAIN TO SNOW AS YOU MOVE SOUTHEAST TO NORTHWEST THROUGH THIS PCPN AREA... WITH SOME SLEET IN THE TRANSITION ZONE. THERE IS SOME FZDZ AND FREEZING RAIN AROUND... ALTHOUGH IT APPEARS TO BE MAINLY IN THE LIGHTER PCPN SOUTH OF THE MAIN AXIS OF PCPN... PRIMARILY FROM NEAR LITCHFIELD SOUTHWEST TO REDWOOD FALLS. THINKING IS THAT THIS AREA IS SEEING THE MID-LEVELS DRY OUT A BIT AS THE PCPN MOVES NORTH... AND HAS AN ENTIRE SUB-FREEZING SOUNDING... BUT IS NOT COLD ENOUGH TO GET ICE CRYSTALS TO FORM IN THE SATURATED LAYER. THIS COULD CONTINUE TO BE A BIT OF A HEADACHE OVER PORTIONS OF SOUTH CENTRAL AND EAST CENTRAL MINNESOTA THROUGH THE AFTERNOON AS THE COLD AIR SURGES IN... BUT THE MOISTURE DEPTH REMAINS LIMITED... SO THERE CONTINUES TO BE A NEED TO MENTION SOME FZRA/FZDZ IN THE FORECAST. DEEPER MOISTURE DOES EVENTUALLY ARRIVE ON THE BACK SIDE OF THE SURFACE LOW AS IT MOVE THROUGH THE METRO NORTHEAST INTO WISCONSIN... WHICH WILL WORK TO TAKE CARE OF THIS ISSUE. THE RUC HAS A GOOD HANDLE ON THE CURRENT LOW LEVEL TEMPERATURES... WIND FIELDS... AND LOW POSITION... AND FAVOR ITS DEPICTION OF THINGS THROUGH THE REMAINDER OF THE DAY... WHICH LINES UP REASONABLY WELL WITH THE PREVIOUS NAM FORECASTS. WITH THAT SAID... THE CURRENT HEADLINES LOOK OK FOR THE MOMENT... BUT THERE MAY BE SOME NEED TO EXTEND WINTER WEATHER ADVISORIES FARTHER SOUTHEAST IF THERE IS MORE IN THE WAY OF FZDZ/FZRA IN THE AFOREMENTIONED ZONE OF MID- LEVEL DRYING. THE REMAINS ADVISORIES AND WARNINGS STILL LOOK ON TRACK... WITH THE SOUTHERN EDGE OF THE HEAVIER SNOW/PCPN LIKELY ANCHORING ITSELF VERY SOON BEFORE PIVOTING THEN LIFTING NORTHEAST... KEEPING THE SAME AREAS WITHIN THE ZONE OF FAVORABLE UPPER DIVERGENCE AND MID-LEVEL FRONTOGENESIS FOR AN EXTENDED PERIOD OF TIME THROUGH THE AFTERNOON HOURS. IT APPEARS THE SOUTHEAST EDGE OF THIS MAIN PCPN BAND WILL ANCHOR FROM NEAR GRANITE FALLS NORTHEAST THROUGH ST CLOUD TO MORA... WITH AREAS NORTH OF THAT SEEING THE GREATEST SNOW POTENTIAL... WHICH LINES UP WELL WITH CURRENT WARNINGS. STRONGEST WINDS OWING TO THE PRESSURE GRADIENT... ISALLOBARIC CONTRIBUTIONS... AND SURFACE ROUGHNESS ISSUES WILL BE OVER WEST CENTRAL AND SOUTH CENTRAL PORTIONS OF THE FORECAST AREA... WITH THE CURRENT BLIZZARD WARNINGS LOOKING OK WITH RESPECT TO WHERE THOSE STRONG WINDS MESH WITH EXPECTED SNOWFALL. THE METRO AREA WILL LIKELY SEE SOME LIGHT PCPN THROUGH MUCH OF THE AFTERNOON... WITH SOME FZDZ/FZRA POSSIBLE TOWARD MID AFTERNOON AS THE SOUNDING COOLS BELOW FREEZING YET THE MID LEVELS REMAIN TOO DRY TO SEED THINGS WITH ICE NUCLEI. ONCE AGAIN... WILL NEED TO KEEP AN EYE ON THIS POTENTIAL WITH RESPECT TO EXTENDING THE WINTER WEATHER ADVISORY. REGARDLESS... THE COLD AIR WILL ARRIVE IN EARNEST ON THE HEELS OF STRONG WESTERLY WINDS AROUND AND AFTER 3PM IN THE METRO... WHICH COULD WORK TO QUICKLY ICE UP THE CURRENTLY WET SURFACES EVEN IF FREEZING PCPN DOESN/T MATERIALIZE. WILL BE WORKING ON SOME UPDATES... WITH UPDATED GRIDS AND ZONE FORECAST COMING... ALTHOUGH CHANGES SHOULD NOT BE TOO SIGNIFICANT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST MONDAY FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-DAKOTA- DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MORRISON-NICOLLET- POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY- STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-WASHINGTON- WATONWAN-WRIGHT-YELLOW MEDICINE. BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR CHIPPEWA-DOUGLAS- LAC QUI PARLE-POPE-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BENTON- KANABEC-KANDIYOHI-MILLE LACS-MORRISON-STEARNS-TODD. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CHISAGO- ISANTI-MEEKER-REDWOOD-RENVILLE-SHERBURNE-WRIGHT. WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BARRON- POLK-RUSK. && $$ TRH/PDP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 950 AM CST SUN DEC 14 2008 .UPDATE... INCREASED WINDS/GUSTS IN FCST TODAY TO BETTER REFLECT CURRENT OBSERVATIONS. FOR PAST SEVERAL HRS KDYT AND DULM5 HAVE BEEN SUSTAINED AROUND 30 KT...WITH GUSTS AROUND 40 KTS. AT 1530Z KDYT HAD A GUST TO 45 KT. EXPECTED THESE WINDS TO PERSIST...OR BECOME STRONGER THROUGH THE AFTERNOON AS THE SFC LOW MOVES INTO NRN WIS. UP T0 60 MPH WILL BE POSSIBLE AT THE HEAD OF LAKE SUPERIOR IN THE DULUTH/SUPERIOR HARBOR THIS AFTERNOON. AREA OF +SN AND 1/2SM OR LESS VSBY CONTINUING GOOD PACE LIFTING NWRD...WITH LEADING EDGE ON TRACK TO REACH THE TWIN PORTS IN THE NEXT 30 MIN. WATCHING SOUTH SHORE ZONES FOR A POSSIBLE UPGRADE TO BLIZZARD WARNING. THE SFC OBSERVATIONS ARE ONLY GUSTING AROUND 25KT...BUT WILL KEEP IN CONTACT WITH LOCAL LAW ENFORCEMENT IN BAYFIELD/ASHLAND/IRON COUNTIES IN CASE WHITE OUT CONDITIONS BECOME WIDESPREAD. ALSO KEEPING CLOSE WATCH ON RA/SN TRANSITION ZONE THAT IS CURRENTLY SET UP ALONG THE DLH/MPX CWA BORDER IN NRN WISCONSIN. LATEST SFC OBS ARE REPORTING RA FROM OSCEOLA...TO RICE LAKE AND LADYSMITH...AND JUST SN JUST TO THE NORTH FROM CAMBRIDGE...TO SIREN...AND PHILLIPS. && .PREV DISCUSSION... /ISSUED 522 AM CST SUN DEC 14 2008/ ..MAJOR STORM AIMING FOR NORTHLAND... ..SIGNIFICANT SNOWFALL FOR MOST LOCATIONS... ...DRAMATIC CHANGES IN TEMPERATURES AND WIND TODAY... ....WINTER STORM WARNING NOW INCLUDES MOST OF NORTHWEST WISCONSIN... DISCUSSION... WELL ADVERTISED SYSTEM BEHAVING AS EXPECTED WITH ONE EXCEPTION. DOME OF COLD AIR IN SFC/85H LAYER HAS MAINTAINED ITSELF ACROSS NW WIS EARLY THIS MORNING. ANIMATION OF RUC13 THERMAL/WIND FIELDS IN BDRY LAYER INDICATE THAT COLDER AIR IS UNDERCUTTING SOUTHWEST FLOW ALOFT. 925H WINDS HAVE SHIFTED FROM SOUTH TO EAST ALONG A RZN TO HYR TO PBH LINE. THIS HAS PUSHED MAIN CONVERGENCE ZONE IN LOW LEVELS FARTHER SOUTH TO ERN PART OF MPX CWA. BAYFIELD PENINSULA APPEARS TO BE EXPERIENCING ENHANCED PRECIP FROM LONG TRAJECTORY DOWN LAKE SUPERIOR. LATEST MSAS SHOWS WELL DEFINED SFC INVERTED TROUGH FROM LOW OVER ERN NEB TO EAX TO HOUGHTON IN UP OF MI. 3HR PRESSRR OVER SERN PART OF CWA CURRENTLY. LATEST SAT IMAGERY SHOWS LARGE AREA OF COOLING CLOUD TOPS ACROSS ERN DAKOTAS IN VICINITY OF DIVERGENCE ASSOCIATED WITH UPPER TROF. STRONG UPPER JETS POISED OVER ONTARIO... WITH NRN BRANCH... AND LEFT EXIT REGION OF SRN PLAINS JET TRANSLATING NE INTO SRN MN/WI. TODAY/TONIGHT...ONLY SIGNIFICANT CHANGE TO EXISTING FCST WAS TO UPGRADE BURNETT/WASHBURN/SAWYER COUNTIES TO WSW. THIS IS PRIMARILY BECAUSE EXISTING THERMAL BDRY IN LOW LAYERS AND UNDERCUTTING OF COLD AIR SHOULD ENSURE MOSTLY SNOW FOR THE MAJORITY OF THE STORM. FSCT SNDGS ALSO REFLECT THIS CHANGE FROM YESTERDAY. BLIZZARD CONDITIONS STILL EXPECTED TODAY ALONG HEAD OF LAKE AS FUNNELING OF HIGHER SPEED AIR OCCURS. DYT ALREADY GUSTING TO ABOUT 40MPH. MAJOR FORCING FACTORS STILL IN PLAY. A LARGE AREA OF MDT/STRONG FRONTOGENESIS WILL BE ENHANCED AS UPPER TROF ADVECTS EAST TODAY. COUPLED JETS WILL ADD TO SYNOPTIC SCALE ASCENT. SOME MIX OF SN/IP/FZRA ACROSS EXTREME ERN CWA AS SFC LOW GETS CLOSER THIS AFTERNOON. WITH COLD AIR ALREADY IN PLACE AND SATURATION OCCURING IN DEEP LAYER SUSPECT THAT POPTYP MAY BE MORE A WET SNOW OR SLEET VS COLD RAIN IN THIS AREA. WINDCHILL VALUES APPROACH/EXCEED ADVISORY CATEGORY TONIGHT BUT DID NOT WANT TO ADD ANOTHER ADVISORY TO BUSY SLATE. WILL VERBALIZE THE THREAT IN THE WSW AND HWO PRODUCTS. TEMPERATURES WILL DROP BELOW ZERO OVER MOST OF THE REGION TONIGHT AND REMAIN BELOW ZERO PERHAPS UNTIL WEDNESDAY AFTERNOON. PLENTY OF BLOWING SNOW EXPECTED AS GUSTY WINDS PUSH FLUFFY LOW DENSITY FLAKES ALL OVER THE PLACE. MONDAY...STORM LOOSENS ITS GRIP BY MONDAY AFTERNOON OVER CWA. SN/BS STILL EXPECTED THROUGH MORNING MOST AREAS. WITH 85/70H RH STILL ABOVE 60 PERCENT MOST OF DAY...SHOULD SEE ADDITIONAL SNOW FOR SNOWBELT WITH VERY HIGH SNOW/LIQUID RATIOS. MAY NEED TO EXTEND WARNING IN THAT AREA. EXTENDED....TUE THRU SAT... SEVERAL S/WVS WILL TRANSIT THE REGION...REQUIRING AT LEAST SOME LOW POPS. THE DRY ARCTIC AIR THAT WILL BE IN PLACE WILL LIMIT ANY POTENTIAL PRECIP. THE MOST LIKELY DRY PD WILL BE WED/THU UNDER WK RIDGING ALOFT...ALTHO SRN ZONES MAY RECEIVE SOME PRECIP BEING ON THE NRN FRINGES OF A SFC SYSTEM MOVG UP THE OH VLY. BOTH GFS AND ECMWF SHOW THIS SYSTEM...ALTHO THERE ARE TIMING DIFFS. AVIATION... GENERALLY IFR/LIFR CONDS IN SN/FG/BLSN WILL PERSIST THRU THE TAF PD AS MAJ WINT STORM MOVES FROM NEB TO LK SUP BY MON MRNG. AT THAT TIME CONDS WILL BEGIN TO GRADUALLY IMPROVE AS THE STORM MOVES AWAY. STRONG NE WINDS WILL SIFT TO THE NW AS THE STORM PASSES...THEN GRADUALLY DIMINISH DURING THE DAY ON MON. && POINT TEMPS/POPS... DLH 21 -10 -5 -21 / 100 80 40 10 INL -1 -11 -6 -28 / 100 80 40 10 BRD 17 -9 -4 -18 / 100 80 20 10 HYR 30 -4 1 -19 / 100 80 30 10 ASX 26 -2 3 -14 / 100 80 50 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR CENTRAL ST. LOUIS-KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR CARLTON/SOUTHERN ST. LOUIS. WI...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR BURNETT-SAWYER- WASHBURN. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR ASHLAND-BAYFIELD- IRON. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR DOUGLAS. WINTER WEATHER ADVISORY UNTIL 4 AM CST MONDAY FOR PRICE. LS...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM CST TUESDAY FOR LSZ121-LSZ146-LSZ147-LSZ148. GALE WARNING UNTIL 4 AM CST MONDAY FOR LSZ121-LSZ144-LSZ145- LSZ146-LSZ147-LSZ148. SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM CST MONDAY FOR LSZ144- LSZ145. SMALL CRAFT ADVISORY UNTIL 4 PM CST MONDAY FOR LSZ140-LSZ141- LSZ142-LSZ143. $$ GRANING/EOM mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 930 AM CST SUN DEC 14 2008 .UPDATE... LATEST RADAR IMAGERY SHOWS BAND OF PCPN LIFTING NORTH AND BEGINNING TO PIVOT OVER THE AREA. PCPN TYPE GOES FROM RAIN TO SNOW AS YOU MOVE SOUTHEAST TO NORTHWEST THROUGH THIS PCPN AREA... WITH SOME SLEET IN THE TRANSITION ZONE. THERE IS SOME FZDZ AND FREEZING RAIN AROUND... ALTHOUGH IT APPEARS TO BE MAINLY IN THE LIGHTER PCPN SOUTH OF THE MAIN AXIS OF PCPN... PRIMARILY FROM NEAR LITCHFIELD SOUTHWEST TO REDWOOD FALLS. THINKING IS THAT THIS AREA IS SEEING THE MID-LEVELS DRY OUT A BIT AS THE PCPN MOVES NORTH... AND HAS AN ENTIRE SUB-FREEZING SOUNDING... BUT IS NOT COLD ENOUGH TO GET ICE CRYSTALS TO FORM IN THE SATURATED LAYER. THIS COULD CONTINUE TO BE A BIT OF A HEADACHE OVER PORTIONS OF SOUTH CENTRAL AND EAST CENTRAL MINNESOTA THROUGH THE AFTERNOON AS THE COLD AIR SURGES IN... BUT THE MOISTURE DEPTH REMAINS LIMITED... SO THERE CONTINUES TO BE A NEED TO MENTION SOME FZRA/FZDZ IN THE FORECAST. DEEPER MOISTURE DOES EVENTUALLY ARRIVE ON THE BACK SIDE OF THE SURFACE LOW AS IT MOVE THROUGH THE METRO NORTHEAST INTO WISCONSIN... WHICH WILL WORK TO TAKE CARE OF THIS ISSUE. THE RUC HAS A GOOD HANDLE ON THE CURRENT LOW LEVEL TEMPERATURES... WIND FIELDS... AND LOW POSITION... AND FAVOR ITS DEPICTION OF THINGS THROUGH THE REMAINDER OF THE DAY... WHICH LINES UP REASONABLY WELL WITH THE PREVIOUS NAM FORECASTS. WITH THAT SAID... THE CURRENT HEADLINES LOOK OK FOR THE MOMENT... BUT THERE MAY BE SOME NEED TO EXTEND WINTER WEATHER ADVISORIES FARTHER SOUTHEAST IF THERE IS MORE IN THE WAY OF FZDZ/FZRA IN THE AFOREMENTIONED ZONE OF MID- LEVEL DRYING. THE REMAINS ADVISORIES AND WARNINGS STILL LOOK ON TRACK... WITH THE SOUTHERN EDGE OF THE HEAVIER SNOW/PCPN LIKELY ANCHORING ITSELF VERY SOON BEFORE PIVOTING THEN LIFTING NORTHEAST... KEEPING THE SAME AREAS WITHIN THE ZONE OF FAVORABLE UPPER DIVERGENCE AND MID-LEVEL FRONTOGENESIS FOR AN EXTENDED PERIOD OF TIME THROUGH THE AFTERNOON HOURS. IT APPEARS THE SOUTHEAST EDGE OF THIS MAIN PCPN BAND WILL ANCHOR FROM NEAR GRANITE FALLS NORTHEAST THROUGH ST CLOUD TO MORA... WITH AREAS NORTH OF THAT SEEING THE GREATEST SNOW POTENTIAL... WHICH LINES UP WELL WITH CURRENT WARNINGS. STRONGEST WINDS OWING TO THE PRESSURE GRADIENT... ISALLOBARIC CONTRIBUTIONS... AND SURFACE ROUGHNESS ISSUES WILL BE OVER WEST CENTRAL AND SOUTH CENTRAL PORTIONS OF THE FORECAST AREA... WITH THE CURRENT BLIZZARD WARNINGS LOOKING OK WITH RESPECT TO WHERE THOSE STRONG WINDS MESH WITH EXPECTED SNOWFALL. THE METRO AREA WILL LIKELY SEE SOME LIGHT PCPN THROUGH MUCH OF THE AFTERNOON... WITH SOME FZDZ/FZRA POSSIBLE TOWARD MID AFTERNOON AS THE SOUNDING COOLS BELOW FREEZING YET THE MID LEVELS REMAIN TOO DRY TO SEED THINGS WITH ICE NUCLEI. ONCE AGAIN... WILL NEED TO KEEP AN EYE ON THIS POTENTIAL WITH RESPECT TO EXTENDING THE WINTER WEATHER ADVISORY. REGARDLESS... THE COLD AIR WILL ARRIVE IN EARNEST ON THE HEELS OF STRONG WESTERLY WINDS AROUND AND AFTER 3PM IN THE METRO... WHICH COULD WORK TO QUICKLY ICE UP THE CURRENTLY WET SURFACES EVEN IF FREEZING PCPN DOESN/T MATERIALIZE. WILL BE WORKING ON SOME UPDATES... WITH UPDATED GRIDS AND ZONE FORECAST COMING... ALTHOUGH CHANGES SHOULD NOT BE TOO SIGNIFICANT. && .AVIATION.../06Z TAF ISSUANCE/ WRMFNT EXTENDING FM SFC LOW ANCHORED IN NE CO THEN ACRS S MN. -SN HAS BEEN SHWG SM EXPANSION ACRS CNTL MN DRNG EVE WITH FAIRLY WDSPRD VSBYS 1-3SM. STG UVV MVS INTO W MN BY 12Z SPRDG RPDLY EWRD ACRS CNTRL MN DRNG MRNG AS UPR LOW APRCHS. THIS WL RPDLY DVLP MDT/HVY SNW ESP AT AXN BUT ALSO AT STC. INCRSG LOW LVL FLOW/WAA OVERNITE MAY DVLP -RA OVER WC WI OVERNITE PERHAPS INTO MSP. SMALL THREAT OF -FZRA BUT WITH SFC DWPTS GNRLY AOA 32 DEGREES SHUD BE MAINLY -RA. BIG DIFFERENCE IN QPF OUTPUT ACRS N AND CNTL WI BTWN 12Z AND 18Z WITH 00Z GFS VERY AGGRESSIVE AS 850MB INCRS TO 50 KTS AND SIGNIFICANT TIGHTENING OF THERMAL GRADIENT. CONCERN FOR MANY HRS OF BLSN AT AXN DVLPG SUN MRNG AND CONTG INTO SUNDAY EVE WITH NRLY WINDS ON BACKSIDE OF SFC LOW. -RA SHUD RPDLY CHG TO -SN AT RWF SUN MRNG AND BY ARND 18Z AT MSP AS COLDER AIR WRAPS IN. && .PREV DISCUSSION... DELAY IN DISCUSSION DUE TO COMPLEX YET EXCITING FORECAST. CHALLENGES CENTER ON BLIZZARD CONDITIONS TODAY IN WEST CTRL MN...WITH BLIZZARD-LIKE OBSERVATIONS ALREADY COMING IN FROM MADISON MN AT 630 AM. THEN FOCUS TURNS TO THE SHARP DROP IN TEMPS...WITH READINGS IN JUST 24 HOURS /7 AM MONDAY/ TO BE 35 TO 45 DEGREES COLDER. SURFACE BOUNDARY EXHIBITING COLD FRONTAL CHARACTERISTICS ACROSS WRN MN WITH COLD BOUNDARY LAYER UNDERCUTTING FORCING AND INSTABILITY FOR SNOW ALOFT. SATELLITE REVEALS AN AREA OF IDEAL CLOUD TOP TEMPERATURES FOR DENDRITIC GROWTH...AND SHORT TERM MODEL AND SIMPLY RADAR TRENDS ARE PORTRAYING VERY GOOD POTENTIAL FOR BANDING SNOW IN WEST CTRL MN THROUGH TODAY. COBB TECHNIQUE FROM NAM/GFS MODELS HAS CONSISTENTLY SHOWN WHAT WILL BE A RAPIDLY INCREASE SNOW TO LIQUID RATIO WITH THE SNOW THANKS TO THE COLD AIR ADVECTION. SO FORECAST SNOWFALL AMOUNTS COME OUT TO 5 TO 12 INCHES ACROSS WRN AND CTRL MN. THE FOCUS FOR BANDING AND JUST THE PROLONGED DURATION OF SNOW WOULD HIGHLIGHT MORRIS...ALEXANDRIA...AND LONG PRAIRIE TO SEE 9 TO 12 INCH AMOUNTS WITH ISOLATED HIGHER AMOUNTS POSSIBLE GIVEN BANDING. THESE FORECAST GENERAL SNOWFALL AMOUNTS FALL OUT WELL WITH EMPIRICAL TECHNIQUES AS WELL. GUIDANCE IN VERY GOOD AGREEMENT ON MASS FIELD PLACEMENT...AND THIS HEAVY SNOW AXIS LIES BETWEEN THE H8 AND H7 LOWS AND HELPS LEND EVEN MORE CONFIDENCE. TO THE EAST...MIXED PRECIP...ALBEIT LIGHT IN THE AFTN...MAY STAY MIXED UNTIL VERY LATE IN THE DAY. SOME ICE ACCUMULATIONS ARE POSSIBLE ALONG THE TIGHT H9-H8 BAROCLINIC ZONE /U.S. HIGHWAY 8 CORRIDOR OF WRN WI/ WHERE FORECAST SOUNDINGS SHOW A DEEP ENOUGH NEAR-SURFACE COLD LAYER TO PROMOTE FREEZING RAIN. SREF PROBABILITIES ALSO HIGHLIGHT THAT AREA. WINDS FOR BLIZZARD CONDITIONS ALREADY SETTING IN. WHILE NOT THE GREATEST SETUP FOR WESTERN MINNESOTA...THE OVERALL LOW LEVEL PRESSURE GRADIENT FORCE IS SO STRONG THAT WINDS WILL GUST TO 35 TO 40 MPH THROUGHOUT TODAY. SIMILAR PRESSURE GRADIENT SPACING LED TO SUCH WINDS IN THE DAKOTAS AND THE SIMILARITIES IN TOPOGRAPHY OF WEST CTRL MN TO THE DAKOTAS WILL HELP. ALREADY GUSTS TO 40-45 MPH HAVE BEEN OBSERVED IN LAC QUI PARLE COUNTY. BEST ISALLOBARIC COUPLET/COLD AIR ADVECTION/1000-850MB DIVERGENCE MOVES FROM WEST TO EAST ACROSS SRN MN THIS AFTN. THIS AREA WILL NOT SEE THAT MUCH FRESH SNOW...BUT THE WINDS MAY BE STRONG ENOUGH TO LEAD TO SOME BLOWING SNOW OF WHAT REMAINS. GUSTS OF 40 TO 45 MPH ARE VERY POSSIBLE THIS AFTN AND EVE. WIND CHILLS PLUMMET THROUGH THE NIGHT TONIGHT WITH THE WINDS CONTINUING AND COLD AIR ADVECTION AS WELL. TEMPS LIKELY TO FALL ALL THE WAY THROUGH MON MORNING BEFORE CLIMBING ONLY SLIGHTLY DURING THE AFTN. FORECAST WIND CHILLS OF -20 TO -35 ACROSS THE MN CWA...THE NATURE IN WHICH IT ARRIVES...AND BEING THE FIRST DOSE OF SUCH AIR THIS WINTER...IT ALL WARRANTED WIND CHILL ADVISORY ISSUANCE BEGINNING AT MIDNIGHT. MAY NEED TO BE EXTENDED THROUGH MON AFTN. MIN TEMPS MON NIGHT LOOK TO BE -20F OR BELOW IN THE AREA THAT SEES THE MOST FRESH SNOW. WITH THE ARCTIC HIGH...THE MSLP AND H8 TEMPS WITH FRESH SNOW...IT ALL DOES FAVOR MIN TEMPS OF THAT MAGNITUDE LOOKING AT SOME LOCAL CLIMATOLOGY. BEYOND...TUES SYSTEM LOOKING MORE INTERESTING WITH SHARP H7 TROUGH LIFTING NORTHEAST OVER THE AREA. SOME MINOR ACCUMULATIONS ARE FAVORED WITH THIS SETUP ON TUES AFTN AND NIGHT. WILL NEED TO FOCUS ON MORE AS WE GET INTO THE WAKE OF THIS SYSTEM. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST MONDAY FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-DAKOTA- DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MORRISON-NICOLLET- POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY- STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-WASHINGTON- WATONWAN-WRIGHT-YELLOW MEDICINE. BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR CHIPPEWA-DOUGLAS- LAC QUI PARLE-POPE-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BENTON- KANABEC-KANDIYOHI-MILLE LACS-MORRISON-STEARNS-TODD. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CHISAGO- ISANTI-MEEKER-REDWOOD-RENVILLE-SHERBURNE-WRIGHT. WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BARRON- POLK-RUSK. && $$ TRH/RAH/MTF mn AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DULUTH MN 522 AM CST SUN DEC 14 2008 ...MAJOR STORM AIMING FOR NORTHLAND... ...SIGNIFICANT SNOWFALL FOR MOST LOCATIONS... ....DRAMATIC CHANGES IN TEMPERATURES AND WIND TODAY... .....WINTER STORM WARNING NOW INCLUDES MOST OF NORTHWEST WISCONSIN... .DISCUSSION... WELL ADVERTISED SYSTEM BEHAVING AS EXPECTED WITH ONE EXCEPTION. DOME OF COLD AIR IN SFC/85H LAYER HAS MAINTAINED ITSELF ACROSS NW WIS EARLY THIS MORNING. ANIMATION OF RUC13 THERMAL/WIND FIELDS IN BDRY LAYER INDICATE THAT COLDER AIR IS UNDERCUTTING SOUTHWEST FLOW ALOFT. 925H WINDS HAVE SHIFTED FROM SOUTH TO EAST ALONG A RZN TO HYR TO PBH LINE. THIS HAS PUSHED MAIN CONVERGENCE ZONE IN LOW LEVELS FARTHER SOUTH TO ERN PART OF MPX CWA. BAYFIELD PENINSULA APPEARS TO BE EXPERIENCING ENHANCED PRECIP FROM LONG TRAJECTORY DOWN LAKE SUPERIOR. LATEST MSAS SHOWS WELL DEFINED SFC INVERTED TROUGH FROM LOW OVER ERN NEB TO EAX TO HOUGHTON IN UP OF MI. 3HR PRESSRR OVER SERN PART OF CWA CURRENTLY. LATEST SAT IMAGERY SHOWS LARGE AREA OF COOLING CLOUD TOPS ACROSS ERN DAKOTAS IN VICINITY OF DIVERGENCE ASSOCIATED WITH UPPER TROF. STRONG UPPER JETS POISED OVER ONTARIO... WITH NRN BRANCH... AND LEFT EXIT REGION OF SRN PLAINS JET TRANSLATING NE INTO SRN MN/WI. TODAY/TONIGHT...ONLY SIGNIFICANT CHANGE TO EXISTING FCST WAS TO UPGRADE BURNETT/WASHBURN/SAWYER COUNTIES TO WSW. THIS IS PRIMARILY BECAUSE EXISTING THERMAL BDRY IN LOW LAYERS AND UNDERCUTTING OF COLD AIR SHOULD ENSURE MOSTLY SNOW FOR THE MAJORITY OF THE STORM. FSCT SNDGS ALSO REFLECT THIS CHANGE FROM YESTERDAY. BLIZZARD CONDITIONS STILL EXPECTED TODAY ALONG HEAD OF LAKE AS FUNNELING OF HIGHER SPEED AIR OCCURS. DYT ALREADY GUSTING TO ABOUT 40MPH. MAJOR FORCING FACTORS STILL IN PLAY. A LARGE AREA OF MDT/STRONG FRONTOGENESIS WILL BE ENHANCED AS UPPER TROF ADVECTS EAST TODAY. COUPLED JETS WILL ADD TO SYNOPTIC SCALE ASCENT. SOME MIX OF SN/IP/FZRA ACROSS EXTREME ERN CWA AS SFC LOW GETS CLOSER THIS AFTERNOON. WITH COLD AIR ALREADY IN PLACE AND SATURATION OCCURING IN DEEP LAYER SUSPECT THAT POPTYP MAY BE MORE A WET SNOW OR SLEET VS COLD RAIN IN THIS AREA. WINDCHILL VALUES APPROACH/EXCEED ADVISORY CATEGORY TONIGHT BUT DID NOT WANT TO ADD ANOTHER ADVISORY TO BUSY SLATE. WILL VERBALIZE THE THREAT IN THE WSW AND HWO PRODUCTS. TEMPERATURES WILL DROP BELOW ZERO OVER MOST OF THE REGION TONIGHT AND REMAIN BELOW ZERO PERHAPS UNTIL WEDNESDAY AFTERNOON. PLENTY OF BLOWING SNOW EXPECTED AS GUSTY WINDS PUSH FLUFFY LOW DENSITY FLAKES ALL OVER THE PLACE. MONDAY...STORM LOOSENS ITS GRIP BY MONDAY AFTERNOON OVER CWA. SN/BS STILL EXPECTED THROUGH MORNING MOST AREAS. WITH 85/70H RH STILL ABOVE 60 PERCENT MOST OF DAY...SHOULD SEE ADDITIONAL SNOW FOR SNOWBELT WITH VERY HIGH SNOW/LIQUID RATIOS. MAY NEED TO EXTEND WARNING IN THAT AREA. EXTENDED....TUE THRU SAT... SEVERAL S/WVS WILL TRANSIT THE REGION...REQUIRING AT LEAST SOME LOW POPS. THE DRY ARCTIC AIR THAT WILL BE IN PLACE WILL LIMIT ANY POTENTIAL PRECIP. THE MOST LIKELY DRY PD WILL BE WED/THU UNDER WK RIDGING ALOFT...ALTHO SRN ZONES MAY RECEIVE SOME PRECIP BEING ON THE NRN FRINGES OF A SFC SYSTEM MOVG UP THE OH VLY. BOTH GFS AND ECMWF SHOW THIS SYSTEM...ALTHO THERE ARE TIMING DIFFS. && .AVIATION... GENERALLY IFR/LIFR CONDS IN SN/FG/BLSN WILL PERSIST THRU THE TAF PD AS MAJ WINT STORM MOVES FROM NEB TO LK SUP BY MON MRNG. AT THAT TIME CONDS WILL BEGIN TO GRADUALLY IMPROVE AS THE STORM MOVES AWAY. STRONG NE WINDS WILL SIFT TO THE NW AS THE STORM PASSES...THEN GRADUALLY DIMINISH DURING THE DAY ON MON. && POINT TEMPS/POPS... DLH 21 -10 -5 -21 / 100 80 40 10 INL -1 -11 -6 -28 / 100 80 40 10 BRD 17 -9 -4 -18 / 100 80 20 10 HYR 30 -4 1 -19 / 100 80 30 10 ASX 26 -2 3 -14 / 100 80 50 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR CENTRAL ST. LOUIS-KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR CARLTON/SOUTHERN ST. LOUIS. WI...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR ASHLAND-BAYFIELD- IRON. BLIZZARD WARNING UNTIL 12 PM CST MONDAY FOR DOUGLAS. WINTER STORM WARNING UNTIL 4 AM CST MONDAY FOR BURNETT-SAWYER- WASHBURN. WINTER WEATHER ADVISORY UNTIL 4AM CST MONDAY FOR PRICE. LS...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM CST TUESDAY FOR LSZ121-LSZ146-LSZ147-LSZ148. GALE WARNING UNTIL 4 AM CST MONDAY FOR LSZ121-LSZ144-LSZ145- LSZ146-LSZ147-LSZ148. SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM CST MONDAY FOR LSZ144- LSZ145. SMALL CRAFT ADVISORY UNTIL 4 PM CST MONDAY FOR LSZ140-LSZ141- LSZ142-LSZ143. $$ CANNON/04 mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 356 PM CST SAT DEC 13 2008 .DISCUSSION...OUR STRING OF UNSEASONABLY COOL WEATHER WILL BE COMING TO AN END THIS WEEK AS SOUTHERLY WINDS WILL BRING AN INCREASE IN MOISTURE ACROSS THE ARKLAMISS. CURRENT RUC ANALYSIS INDICATES HIGH PRESSURE CONTINUING TO SLIDE OFF TO THE EAST AND BECOMING CENTERED OVER NJ/DE/MD. AS THIS MOVES OFF...UPPER LEVEL TROUGH OVER IDAHO AND SFC LOW OVER COLORADO CONTINUE TO DROP SOUTHEAST. THIS IS CREATING A TIGHTENING PRESSURE GRADIENT AND VERY GUSTY WINDS OVER THE PLAINS INTO TEXAS. DENSE CIRRUS HAS COVERED MOST OF THE CWA AND THIS HAS ALLOWED TEMPERATURES TO ONLY WARM INTO THE MID TO UPPER 40S. AREAS THAT HAVE SEEN BREAKS IN THE CLOUDS HAVE REACHED INTO THE 50S. FOR TONIGHT...EXPECT LOW PRESSURE OUT WEST TO CONTINUE TO TRACK EAST/SOUTHEAST. THIS WILL CONTINUE TO INCREASE WINDS AHEAD OF THE ASSOCIATED FRONT AND CAUSE GUSTY WINDS OVER MAINLY THE NW PORTIONS OF THE CWA. WITH THIS SAID...HAVE GONE AND EXPANDED THE LAKE WIND ADVISORY TO COVER GENERALLY THE AREAS BOUNDED BY INTERSTATE 55 AND INTERSTATE 20. THIS AREA IS LIKELY TO SEE THE GREATEST WINDS OVERNIGHT. IN ADDITION...GIVEN SOUTHERLY FLOW...EXPECT SOME WARM ADVECTION RAIN TO OCCUR OVERNIGHT TONIGHT...MAINLY WEST OF THE MS RIVER AFTER MIDNIGHT. SUNDAY...AS SOUTHERN STREAM 120KT 200MB JET MOVES OVER THE CWA...AND FRONT APPROACHES FROM THE WEST...CONTINUED GUSTY WINDS WILL PREVAIL. THE HIGHEST SPEEDS WILL AGAIN BE IN THE MS DELTA AND AR COUNTIES. WITH THIS SAID HAVE ISSUED A WIND ADVISORY AS SPEEDS WILL LIKELY AT LEAST BRIEFLY REACH CRITERIA. THE REST OF THE CWA...WITH EXCEPTION OF GENERALLY THE I-59 CORRIDOR...HAVE GONE WITH LAKE WIND ADVISORY. WARM ADVECTION RAIN WILL BE POSSIBLE FOR ALL LOCATIONS EXCEPT THE NORTHEAST AS RETURN FLOW STEADILY BRINGS PWATS INTO THE 1-1.15 RANGE. BY SUNDAY NIGHT...WINDS SHOULD BEGIN TO SUBSIDE SOME. WARM ADVECTION RAIN WILL BE POSSIBLE ACROSS THE ENTIRE AREA AS MOISTURE STREAMS INTO REGION AND THE FRONT CONTINUES TO TRACK CLOSER TO THE REGION. ON MONDAY...AHEAD OF THE FRONT THERE IS THE CHANCE FOR SOME LIGHT RAIN. THE FRONT WILL TRAVERSE THE REGION DURING THE DAY. THERE IS LIMITED INSTABILITY WHICH MAY ALLOW FOR SOME THUNDER. LOOKS LIKE THE FRONT WILL MOVE THROUGH JUST ABOUT THE ENTIRE AREA BY MIDNIGHT...LEAVING LIGHT STRATIFORM RAIN IN ITS WAKE ACROSS MUCH OF MS AND LA. AS FOR TEMPS...WENT WITH GUIDANCE THROUGH THE PERIOD AS WARM ADVECTION WILL ALLOW FOR TEMPERATURES TO WARM INTO THE 60S AND 70S DURING THE DAY. CLOUD COVER AND RAIN WILL LIMIT THE DIURNAL RANGE OF TEMPS AND BRING WARMER LOWS FOR THE CWA THAN WHAT WE HAVE BEEN SEEING OVER THE PAST COUPLE OF WEEKS. AS FOR POPS...GENERALLY WENT WITH GUI POPS. DID RAISE POPS ON MON NIGHT/TUES MORNING AS GUI CAME IN MUCH LOWER THAN WHAT WAS PREVIOUSLY FORECAST. BUMPED UP VALUES TO BLEND A LITTLE MORE WITH PREVIOUS IN THE THINKING THERE MIGHT BE SOME POST FRONTAL RAIN. OTHERWISE...PREVIOUS FORECAST STILL STANDS FOR TUESDAY AND BEYOND. /28/ THE GFS/GFES/ECMWF AND UKMET ALL INDICATE THE CP BOUNDARY WILL AT LEAST REACH THE ARKLAMISS AND STALL IN THE VICINITY TUESDAY. THE ENERGETIC SOUTHWEST FLOW ALOFT AND OCCASIONAL PERTURBATIONS WILL BUCKLE THE BOUNDARY RESULTING IN A FEW ROUNDS OF LIGHT TO MODERATE RAINFALL AND WIDE TEMPERATURE RANGES. THE BEST CHANCE OF RAIN LOOKS TO AGAIN ON WEDNESDAY. DO NOT SEE ANY KIND OF SIGNIFICANT WEATHER AS FAR AS SEVERE AND HEAVY RAIN POTENTIAL ARE CONCERNED. OVERALL...EXPECT TEMPERATURES TO BE A BIT MILDER THAN EXPECTED THIS TIME OF THE YEAR. /EC/17/ && .AVIATION...THE GRADIENT BETWEEN HIGH PRESSURE TO OUR EAST AND LOW PRESSURE TO OUR NORTHWEST WILL MAINTAIN SOUTHERLY WINDS AROUND 15 KTS TONIGHT AND INCREASE TO 15 TO 25KTS OVER THE AREA SUNDAY. THE STRONGEST AND GUSTIEST WINDS ARE EXPECTED OVER THE DELTA REGION. HIGH CLOUDS HAVE INCREASED FROM THE WEST TODAY BUT VFR CONDITIONS PREVAILED. VFR CONDITIONS WILL GIVE WAY TO MVFR AND OCCASIONAL IFR CONDITIONS AFTER MIDNIGHT FROM THE SOUTHWEST AS A LAYER OF STRATUS DEVELOPS AND MOVES OVER THE AREA. A FEW LIGHT SHOWERS ARE EXPECTED TO DEVELOP FROM WEST LATE TONIGHT AS WELL. THIS WILL BE AHEAD OF A COLD FRONT THAT WILL DROP INTO THE AREA SUNDAY NIGHT. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 47 67 58 68 / 12 15 37 40 MERIDIAN 41 63 56 69 / 5 10 53 43 VICKSBURG 50 70 58 65 / 24 22 26 42 HATTIESBURG 44 67 58 73 / 9 15 38 25 NATCHEZ 53 69 60 70 / 22 21 17 31 GREENVILLE 48 67 55 55 / 23 26 45 53 GREENWOOD 48 65 56 60 / 9 19 51 54 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...LAKE WIND ADVISORY FROM 6 AM TO 6 PM CST SUNDAY FOR MSZ029>033- 037>039-043>045-047>051-053>056-059>063. LAKE WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MSZ040>042. LAKE WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR MSZ025>028-035-036. WIND ADVISORY FROM 6 AM TO 6 PM CST SUNDAY FOR MSZ018-019- 025>028-034>036. LAKE WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR MSZ018-019-034. LA...LAKE WIND ADVISORY FROM 6 AM TO 6 PM CST SUNDAY FOR LAZ015-016- 023>026. LAKE WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR LAZ007>009. AR...WIND ADVISORY FROM 6 AM TO 6 PM CST SUNDAY FOR ARZ074-075. LAKE WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR ARZ074-075. && $$ 28/22/17/EC ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 334 PM CST SAT DEC 13 2008 .SHORT TERM...TONIGHT THROUGH TUESDAY. WE HAVE A COUPLE OF STORM SYSTEMS TO CONSIDER IN THE SHORT TERM. HEADLINES...MIXED PRECIP...SNOW AMTS...AND WIND WILL ALL BE OF CONCERN LATE TONIGHT THROUGH SUNDAY EVENING...THEN LOW WIND CHILLS MONDAY MORNING. THE UA CHARTS FROM THIS MORNING HAD A 160KT JET DIVING SOUTHWARD ON THE BACKSIDE OF A TROF OVR THE PACIFIC OCEAN TOWARD CA. 220M HT FALLS WERE NOTED OVR OREGON AND SRN ID WITH COLD -35 DEG TEMPS AT H5. AT H7 STEEP MID LEVEL LAPSE RATES WERE NOTED AHEAD OF THE MID LEVEL TROF. AT H85 A 70 KT JET WAS REPORTED AT TOPEKA. BY 20Z...THE RUC WAS SHOWING A 120-140KT JET OVR CO AND THIS WAS AIDING RIPPLES IN THE FLOW ACRS THE PLAINS. THE GFS DID A BETTER JOB WITH THE PRECIP THAT DEVELOPED OVR MO WITH THE MOISTURE RETURN AND STRONG WAA. THE LATEST SFC ANALYSIS HAD THE TIGHTEST SFC PRES GRADIENT OVR MO AND VERY WARM TEMPS IN OUR CWA IN THE 40S AND 50S. SFC LOW PRES WAS ORGANIZING OVR WY/CO. THE CDFNT WAS SOUTH OF PIR SD AND STRETCHED EASTWARD TO AROUND ST. CLOUD MN. IN OUR AREA...WE HAVE A PSEUDO WRMFNT NORTH OF TQE AND NR DENISON...SOUTH OF THIS BOUNDARY...THERE IS GOOD MIXING WITH TEMPS IN THE 50S AND NORTH OF THE BOUNDARY...TEMPS ARE IN THE 40S WITH LIGHTER SFC WINDS. DECIDED TO GO WITH A WINTER WEATHER ADVISORY STARTING AT MIDNIGHT FOR THE FOUR NORTHERN COUNTIES IN OUR CWA. THE PRECIPITATION MAY START OUT AS FREEZING DRIZZLE OR LIGHT FREEZING RAIN BEFORE SWITCHING OVER TO SNOW. THE TIMING OF THE START OF THE PRECIPITATION IS STILL BTWN 06-09Z WITH THE CD AIR BARRELING IN TO THE NORTHEAST BETWEEN 09-12Z THEN THROUGHOUT THE MORNING FOR THE REST OF THE CWA. IN ADDITION...THE LIGHT SNOW AND BLOWING SNOW WILL REDUCE VISIBILITIES. THE SNOW STILL APPEARS TO BE LIGHT AND COULD SEE A COUPLE OF INCHES AND WILL MENTION 1 TO AS HIGH AS 2 OR 3 NEAR THE SD BORDER. THERE IS A GOOD AGEOSTROPHIC CIRCULATION IN THE NORTH ALONG WITH UVV AND FRONTOGENSIS. Q-VECTO FORCING IS BETTER NORTH AND THE MID LEVEL FRONTOGENESIS APPEARS TO REMAIN IN THE DAKOTAS AND MINNESOTA...THEN TRIES TO DEVELOP OVR SE NEB DURING THE EVENING...BUT IS BETTER ORGANIZED OVR KS AND MO. WITH THE 20-30KT WINDS AND GUSTS 35 TO 40KT ISSUED WIND ADVISORIES FOR SUNDAY ACRS THE REST OF THE CWA. THE WINDS REMAIN STRONG INTO THE EVENING. LEFT SNOWSHOWERS AND FLURRIES IN DURING THE EVENING. THE SOUTHERN SNOWBAND THAT IS PROGGED TO DEVELOP SHOULD REMAIN SOUTH OF THE CWA. WITH THE COLD TEMPERATURE AND STRONG WINDS MONDAY MORNING...WIND CHILL ADVISORY CRITERIA SHOULD BE MET. THE NEXT STORM SYSTEM FOR LATE MONDAY NIGHT AND TUESDAY ALSO LOOKS POTENT AND A BETTER SNOW PRODUCER. STRONG H85 WAA SETS UP AND WITH CD AIR IN PLACE AND STRONG LIFT AND BETTER PV SIGNALS...INCREASED POPS TO THE LIKELY CATEGORY AND ADDED QPF/SNOWAMTS OF 1-4 INCHES. TEMPS STILL 10 TO 20 DEG BELOW NORMAL BOTH MON AND TUESDAY. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. 12Z GFS IS IN REASONABLE AGREEMENT WITH BOTH 00Z AND 12Z ECMWF CONSIDERING THE RATHER LARGE UNCERTAINTIES INHERENT IN A PATTERN OF SW FLOW ALOFT. THESE ARISE FROM SHORT WAVES IN BOTH BRANCHES OF PARTIALLY SPLIT FLOW. SOUTHERN STREAM WAVES TAP INTO GOOD MOISTURE SOURCE TO THE SOUTH...WHILE NORTHERN STREAM PRODUCES NEW SURGES OF ARCTIC AIR. THUS...THE DETAILS OF TIMING THESE WAVES CAN BE EXPECTED TO GO WRONG DURING THIS FORECAST PERIOD. HOWEVER...THERE IS BETTER CONFIDENCE THAT SNOW COVER WILL EXIST OVER MOST OR ALL OF THE AREA...HELPING TO KEEP NEAR SURFACE AIR WELL REFRIGERATED DESPITE OCCASIONAL WARMING ALOFT. EXPECT SEVERAL PUSHES OF ARCTIC AIR...LIKELY ONGOING EARLY WED...THEN AGAIN NEXT FRI OR SAT. IN BETWEEN...WARM ADVECTION WILL SET UP A CHC OF PRECIP MOSTLY THURSDAY INTO EARLY FRIDAY. BOTH GFS AND ECMWF WARM UP THICKNESSES AND TEMPS ALOFT ENOUGH TO SUGGEST THAT THERE COULD BE FREEZING RAIN AT LEAST IN THE SOUTHEAST CORNER OF NEBRASKA AND SW IA DURING THE DAY THU...AS SFC AIR TEMPS ARE NOT EXPECTED TO RISE ABOVE FREEZING. FLURRIES ARE ALSO LIKELY EARLY WED NIGHT AS THE ARCTIC AIR SURGES...AND WITH ANY OTHER LATER SURGE. TEMPS THROUGH THE EXTENDED PERIOD WILL MOSTLY RANGE BETWEEN 0 AND 32...BUT COULD EASILY GO COLDER IF TIMING ALLOWS GOOD RADIATION SOME NIGHT. && .AVIATION... FOR TAF SITES KOFK/KOMA/KLNK THROUGH 14/18Z. STRONG ARCTIC FRONT PUSHING SWD INTO CNTRL PLAINS DURING THE PD. AT THIS POINT...STRONG WIND THREAT AND CROSS WIND ACTIVITY IS THE MAIN CONCERN ALL SITES. SOUTHERLY WINDS WILL REMAIN STRONG UNTIL FROPA...AROUND 08Z AT KOFK/13Z KLNK/14Z KOMA. CROSS WIND ACTIVITY WITH GUSTS 30KT OR GREATER WILL BE DEFINITE FACTOR ALL SITES GENERALLY 2 HOURS LEADING UP TO FROPA. OTHERWISE...CHANCE FOR -SN MAINLY AT KOFK BTW 14/12Z-18Z TIME FRAME. WILL OPT TO NOT INCLUDE -FZRASN MIX FOR KOFK AT THIS TIME...AND WILL REEVALUATE AT NEXT TAF ISSUANCE 14/00Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY FROM 9 AM TO 9 PM CST SUNDAY FOR NEZ045-052-053- 067-068-089>093. WIND ADVISORY FROM 6 AM TO 9 PM CST SUNDAY FOR NEZ015-018- 030>034-042>044-050-051-065-066-078-088. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST SUNDAY FOR NEZ011-012-016-017. IA...WIND ADVISORY FROM 9 AM TO 9 PM CST SUNDAY FOR IAZ043-055-056- 069-079-080-090-091. && $$ ZAPOTOCNY/POLLACK/DEE ne AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE LAS VEGAS NV 1018 PM PST SAT DEC 13 2008 .SYNOPSIS...A SERIES OF STORM SYSTEMS WILL AFFECT THE DESERT SOUTHWEST THROUGH MUCH OF NEXT WEEK. THIS WILL RESULT IN MUCH COLDER TEMPERATURES ALONG WITH A CHANCE FOR RAIN AND SNOW. THE SNOW LEVEL WILL BE UNUSUALLY LOW AFTER SUNDAY NIGHT...WITH SNOW POTENTIALLY DOWN TO THE DESERT FLOORS. && .UPDATE...WIND ADVISORIES HAVE BEEN ALLOWED TO EXPIRE. .905 PM PST UPDATE...COLD FRONT APPEARS TO BE ACROSS THE EASTERN HALF OF MOHAVE COUNTY AS OF 9 PM PST. ISOLATED CONVECTION FORMED EARLIER ALONG THE FRONTAL BOUNDARY...BUT HAS ENDED. SECONDARY MOISTURE BOUNDARY ACROSS SOUTHEAST INYO COUNTY THROUGH SOUTHERN NEVADA WILL BE SHIFTING EAST OVERNIGHT AND WILL PRODUCE ISOLATED SHOWERS MAINLY EAST OF LAS VEGAS THROUGH THE REMAINDER OF THE NIGHT. MAIN CONCERN FOR TONIGHT CONTINUES TO BE THE WIND. CURRENT WIND ADVISORIES EXPIRE AS OF 10 PM PST AND ATTM THAT LOOKS TO BE A GOOD AS THE FRONT EXITS THE AREA. WILL CONTINUE TO MONITOR. WILL BE UPDATING ZONES LATER TO REMOVE WIND ADVISORIES AND TO REMOVE EVENING WORDING...BUT OVERALL CURRENT SHORT TERM FORECAST ON TRACK AND NO FURTHER UPDATES PLANNED FOR TONIGHT. && .AVIATION...FOR MCCARRAN...WINDS WILL CONTINUE TO DECREASE AND SLOWLY TURN MORE WESTERLY BEFORE BECOMING VARIABLE AFT 08Z. CIGS AROUND 8K FEET UNTIL 08Z THEN BCMG SCT CLOUD DECKS THROUGH SUNDAY. THE NEXT SYSTEM WILL BRING THE POTENTIAL FOR CIGS BELOW 5K FEET AND SHOWERS TO THE AREA BY 12Z MONDAY WITH MIXED RAIN/SNOW POSSIBLE... LOWERING VSBY BLO 3SM THROUGH 18Z MONDAY. ANOTHER SYSTEM MAY AFFECT THE AREA WEDNESDAY WITH ANOTHER CHANCE FOR LOW CIGS AND ANOTHER CHANCE FOR MIXED RAIN/SNOW. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...WINDS WILL CONTINUE TO DECREASE ACROSS THE AREA OVERNIGHT WITH GENERALLY NORTH WINDS LESS THAN 15KT AFT 08Z SUNDAY. CIGS NEAR 8K FEET WITH ISOLATED SHOWERS...MAINLY MORMON MESA TO KLAS TO BAKER LINE SOUTH...THROUGH 08Z SUNDAY THEN BECOMING SCT CLOUD DECKS THROUGH THE REMAINDER OF SUNDAY. WINDS WILL BECOMING SOUTHWEST AFTER 00Z MONDAY AS NEXT SYSTEM BEGINS TO APPROACH THE AREA WHICH WILL BRING THE POTENTIAL FOR CIGS BELOW 5K FEET AND SHOWERS TO THE AREA LATE SUNDAY NIGHT INTO MONDAY MORNING. MOUNTAIN OBSCURATIONS ONCE AGAIN LIKELY WITH SNOW LEVELS NEAR THE DESERT FLOORS. ANOTHER SYSTEM LOOKS TO MOVE IN WEDNESDAY WITH ANOTHER CHANCE FOR LOW CIGS AND MIXED RAIN/SNOW IN THE LOWER ELEVATIONS. && .608 PM PST UPDATE...LIGHT SHOWERS ARE EXPECTED TO CONTINUE ACROSS LINCOLN COUNTY THROUGH THE EARLY EVENING HOURS...BUT NO ADDITIONAL SNOW ACCUMULATIONS IS EXPECTED...THUS HAVE ALLOWED THE SNOW ADVISORY TO EXPIRE. COLD FRONT SHIFTING SOUTH SLIGHT FASTER THAN EARLIER THOUGHT WITH FRONT CROSSING OVER THE KLAS VALLEY AS OF 02Z. WINDS REMAIN A PROBLEM ACROSS THE SOUTHERN PORTION OF THE CWA WITH THE ADVISORIES STILL IN EFFECT THROUGH THIS EVENING. && .420 PM PST DISCUSSION...PREFRONTAL WINDS WERE STRONG ACROSS THE SOUTHERN HALF OF THE FORECAST AREA TODAY BUT THE LATEST OBSERVATIONS WERE INDICATING A SLIGHT DECREASING TREND. HIGH DOWNSLOPE WINDS ON THE EAST SLOPES OF THE SPRING MOUNTAINS DECREASED AFTER 21Z AND WILL CONTINUE TO DIMINISH THIS AFTERNOON AND EVENING. A WIND ADVISORY WILL REPLACE HIGH WIND WARNINGS FOR THE SPRING MOUNTAINS...WESTERN SAN BERNARDINO COUNTY AND THE EASTERN SIERRA SLOPES. THE SURFACE PRESSURE GRADIENT WAS STILL 14-15 MB BETWEEN LAX AND LAS BUT THE COLD FRONT WILL PUSH THROUGH CLARK COUNTY BY 03Z AND WINDS WILL DIMINISH BEHIND IT. THE 18Z NAM AND LATEST RUC INDICATE THE FRONT WILL WASH OUT AS IT MOVES THROUGH WITH NO STRONG PUSH OF NORTH WINDS MAKING IT INTO FAR SOUTHERN NEVADA. SNOW SHOWERS OVER LINCOLN COUNTY SHOULD DIMINISH AFTER 02Z BEHIND THE FRONT AND ONLY SCATTERED SHOWERS ARE EXPECTED OVER NORTHERN MOHAVE COUNTY. THE BROAD UPPER LOW SETTLES IN AND ZONAL FLOW SHOULD KEEP THE AREA MAINLY DRY AND COLD SUNDAY BEFORE A SUBSTANTIAL PLUME OF MOISTURE MOVES ACROSS SOUTHERN CALIFORNIA INTO ARIZONA MONDAY. THE NORTHERN EDGE OF THE PLUME WILL BE PULLED ACROSS SOUTHERN NEVADA AND THE LATEST GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE TRACK OF THE UPPER LOW AND MOISTURE. THE SOUTHWEST FLOW WILL BRING SLIGHT WARMING ALOFT BUT SNOW LEVELS WILL STILL BE 2500-3000 FEET OVER SOUTHERN NEVADA MONDAY MORNING. HOWEVER...IT LOOKS LIKE THE MOISTURE SHOT WILL BE RATHER QUICK...BETWEEN 12Z AND 18Z FOR THE VALLEYS. THE MOUNTAINS WILL SEE MORE PROLONGED OROGRAPHICALLY ENHANCED PRECIP. SNOW ACCUMULATIONS WHICH WOULD WARRANT A WATCH SHOULD BE CONFINED TO TERRAIN ABOVE 4000 FEET. HOWEVER...A FEW INCHES OF SNOW ACCUMULATION...ESPECIALLY ON GRASSY SURFACES...ALONG THE FOOTHILLS AROUND THE LAS VEGAS VALLEY STILL LOOK LIKE A DECENT BET. THE GFS BUFR FORECAST SOUNDINGS SHOW A WARMER BOUNDARY LAYER WITH SOUTHERLY WINDS THAN THE NAM BUFR...INDICATING HIGHER WET BULB ZEROS AND SNOW LEVELS CLOSER TO 3000 FEET. PRECIPITATION WILL TAPER OFF MONDAY AFTERNOON AND EVENING AS THE MOISTURE PLUME MOVES ENTIRELY INTO ARIZONA. .LONG TERM...AN UPPER LOW WILL MOVE SOUTHWARD INTO NORCAL BY TUESDAY AFTERNOON WITH ADDITIONAL RIPPLES OF ENERGY MOVING THROUGH THE BASE OF THE UPPER TROUGH WHICH WILL BE RIGHT ACROSS SOCAL/SOUTHERN NEVADA AND NORTHERN AZ. BY TUESDAY AFTERNOON THE LEFT REAR QUAD A 130 KT+ JETSTREAK WILL BE ACROSS THE MOJAVE DESERT ACCOMPANIED BY A PLUME OF PACIFIC MOISTURE. THIS SHOULD PUT THE AREA IN A FAVORABLE REGION TO SEE ANOTHER ROUND OF SHOWERS TUESDAY AFTERNOON AND NIGHT. AS THE UPPER LOW SINKS FURTHER SOUTH TO NEAR POINT CONCEPTION BY WEDNESDAY AFTERNOON THE PROXIMITY OF THE UPPER LOW AS WELL AS A PLUME OF PACIFIC MOISTURE STREAMING INTO THE AREA SHOULD HELP TO INCREASE THE CHANCES FOR SHOWERS TO OCCUR...AND POSSIBLY MORE A STEADIER STRATIFORM TYPE PRECIPITATION EVENT IN THE MOJAVE DESERT. WITH PLENTY OF CHILL AIR ACROSS THE REGION SNOW LEVELS WILL REMAIN QUITE LOW ALLOWING FOR SNOW TO FALL IN AREAS THAT DO NOT OFTEN SEE IT. ONE ISSUE REMAINS JUST HOW FAR NORTHWEST THE MAIN MOISTURE PLUME GETS AS NORTHWEST PARTS OF THE CWFA MAY NOT SEE MUCH IF ANY PRECIP. IN LAS VEGAS...THERE COULD BE THE POTENTIAL ONCE AGAIN FOR SNOW OR A RAIN/SNOW MIX ON WEDNESDAY AS MODEL FORECAST SOUNDINGS SUGGEST P-TYPE COULD BE AN ISSUE. AGAIN THE ISSUE OF EVAPORATIONAL COOLING COULD COME INTO PLAY AS WELL ENHANCING THE PROSPECTS FOR SNOW OR A RAIN/SNOW MIX. WINTER WEATHER PRODUCTS MAY BE NEEDED FOR PARTS OF THE AREA AS THE MOISTURE SUPPLY WILL BE ENOUGH TO SUPPORT ACCUMULATING SNOW IN AT LEAST THE HIGHER PORTIONS OF THE MOJAVE DESERT. BY WEDNESDAY NIGHT THE SYSTEM FINALLY EXITS TO THE EAST AND A DRIER NORTHWEST FLOW TAKES OVER FOR THURSDAY. THE GENERAL CONSENSUS FROM THE OPERATIONAL MODELS AND GFS ENSEMBLES WERE IN DECENT AGREEMENT TO SUPPORT LOWERING POPS SHARPLY AND BRIGHTENING SKIES SOME BUT IT SHOULD STILL REMAIN BELOW NORMAL WITH A SUBTLE RISE IN TEMPS. NEVERTHELESS WE SHOULD CATCH A BREAK FROM THE CLOUDS AND SHOWERS LATER IN THE WEEK. ANOTHER SYSTEM MAY DROP DOWN FROM THE NORTH BY NEXT WEEKEND BUT MODELS REMAIN IN DISAGREEMENT WITH JUST HOW FAR SOUTH IT GETS OR WHEN IT MAY EVEN SHOW UP. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY NIGHT FOR NVZ018-019. AZ...NONE. CA...NONE. && $$ JENSEN/ADAIR/STACHELSKI HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE LAS VEGAS NV 608 PM PST SAT DEC 13 2008 .SYNOPSIS...A SERIES OF STORM SYSTEMS WILL AFFECT THE DESERT SOUTHWEST THROUGH THE WEEKEND AND MUCH OF NEXT WEEK. WINDS WILL DECREASE OVERNIGHT FOLLOWED BY MUCH COLDER TEMPERATURES SUNDAY THROUGH MUCH OF THE WEEK ALONG WITH CHANCES FOR RAIN AND SNOW. THE SNOW LEVEL WILL BE UNUSUALLY LOW AFTER SUNDAY NIGHT...AND SNOW MAY FALL DOWN TO THE DESERT FLOORS. && .UPDATE...LIGHT SHOWERS ARE EXPECTED TO CONTINUE ACROSS LINCOLN COUNTY THROUGH THE EARLY EVENING HOURS...BUT NO ADDITIONAL SNOW ACCUMULATIONS IS EXPECTED...THUS HAVE ALLOWED THE SNOW ADVISORY TO EXPIRE. COLD FRONT SHIFTING SOUTH SLIGHT FASTER THAN EARLIER THOUGHT WITH FRONT CROSSING OVER THE KLAS VALLEY AS OF 02Z. WINDS REMAIN A PROBLEM ACROSS THE SOUTHERN PORTION OF THE CWA WITH THE ADVISORIES STILL IN EFFECT THROUGH THIS EVENING. && .AVIATION...FOR MCCARRAN...COLD FRONT MOVING ACROSS THE KLAS VALLEY AT 02Z WITH WINDS SWITCHING TO THE WEST-NORTHWEST. LOOK FOR WESTERLY FLOW ACROSS KLAS THROUGH 03Z...THEN BECOMING MORE NORTHWEST THROUGH 05Z...BEFORE SWITCHING BACK TO MORE WESTERLY AND THEN BECOMING VARIABLE AFT 08Z. CIGS TO LOWER TO NEAR 80KT FT THROUGH 08Z THEN BECOMING SCT CLOUD DECKS THROUGH SUNDAY. DUST WILL SLOWLY SETTLE WITHIN THE AREA...BUT VSBY SHOULD REMAIN ABOVE 6SM THROUGH THE REMAINDER OF THE NIGHT. THE NEXT SYSTEM WILL BRING THE POTENTIAL FOR CIGS BELOW 5K FEET AND SHOWERS TO THE AREA BY 12Z MONDAY WITH A MIX RAIN/SNOW PRECIPITATION POSSIBLE...LOWERING VSBY BLO 3SM. ANOTHER SYSTEM LOOKS TO AFFECT THE AREA WEDNESDAY WITH ANOTHER CHANCE FOR LOW CIGS AND SHOWERS...WITH YET ANOTHER CHANCE FOR SNOW OR A RAIN/SNOW MIX. && .PREV DISCUSSION...420 PM PST SHORT TERM...PREFRONTAL WINDS WERE STRONG ACROSS THE SOUTHERN HALF OF THE FORECAST AREA TODAY BUT THE LATEST OBSERVATIONS WERE INDICATING A SLIGHT DECREASING TREND. HIGH DOWNSLOPE WINDS ON THE EAST SLOPES OF THE SPRING MOUNTAINS DECREASED AFTER 21Z AND WILL CONTINUE TO DIMINISH THIS AFTERNOON AND EVENING. A WIND ADVISORY WILL REPLACE HIGH WIND WARNINGS FOR THE SPRING MOUNTAINS...WESTERN SAN BERNARDINO COUNTY AND THE EASTERN SIERRA SLOPES. THE SURFACE PRESSURE GRADIENT WAS STILL 14-15 MB BETWEEN LAX AND LAS BUT THE COLD FRONT WILL PUSH THROUGH CLARK COUNTY BY 03Z AND WINDS WILL DIMINISH BEHIND IT. THE 18Z NAM AND LATEST RUC INDICATE THE FRONT WILL WASH OUT AS IT MOVES THROUGH WITH NO STRONG PUSH OF NORTH WINDS MAKING IT INTO FAR SOUTHERN NEVADA. SNOW SHOWERS OVER LINCOLN COUNTY SHOULD DIMINISH AFTER 02Z BEHIND THE FRONT AND ONLY SCATTERED SHOWERS ARE EXPECTED OVER NORTHERN MOHAVE COUNTY. THE BROAD UPPER LOW SETTLES IN AND ZONAL FLOW SHOULD KEEP THE AREA MAINLY DRY AND COLD SUNDAY BEFORE A SUBSTANTIAL PLUME OF MOISTURE MOVES ACROSS SOUTHERN CALIFORNIA INTO ARIZONA MONDAY. THE NORTHERN EDGE OF THE PLUME WILL BE PULLED ACROSS SOUTHERN NEVADA AND THE LATEST GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE TRACK OF THE UPPER LOW AND MOISTURE. THE SOUTHWEST FLOW WILL BRING SLIGHT WARMING ALOFT BUT SNOW LEVELS WILL STILL BE 2500-3000 FEET OVER SOUTHERN NEVADA MONDAY MORNING. HOWEVER...IT LOOKS LIKE THE MOISTURE SHOT WILL BE RATHER QUICK...BETWEEN 12Z AND 18Z FOR THE VALLEYS. THE MOUNTAINS WILL SEE MORE PROLONGED OROGRAPHICALLY ENHANCED PRECIP. SNOW ACCUMULATIONS WHICH WOULD WARRANT A WATCH SHOULD BE CONFINED TO TERRAIN ABOVE 4000 FEET. HOWEVER...A FEW INCHES OF SNOW ACCUMULATION...ESPECIALLY ON GRASSY SURFACES...ALONG THE FOOTHILLS AROUND THE LAS VEGAS VALLEY STILL LOOK LIKE A DECENT BET. THE GFS BUFR FORECAST SOUNDINGS SHOW A WARMER BOUNDARY LAYER WITH SOUTHERLY WINDS THAN THE NAM BUFR...INDICATING HIGHER WET BULB ZEROS AND SNOW LEVELS CLOSER TO 3000 FEET. PRECIPITATION WILL TAPER OFF MONDAY AFTERNOON AND EVENING AS THE MOISTURE PLUME MOVES ENTIRELY INTO ARIZONA. .LONG TERM...AN UPPER LOW WILL MOVE SOUTHWARD INTO NORCAL BY TUESDAY AFTERNOON WITH ADDITIONAL RIPPLES OF ENERGY MOVING THROUGH THE BASE OF THE UPPER TROUGH WHICH WILL BE RIGHT ACROSS SOCAL/SOUTHERN NEVADA AND NORTHERN AZ. BY TUESDAY AFTERNOON THE LEFT REAR QUAD A 130 KT+ JETSTREAK WILL BE ACROSS THE MOJAVE DESERT ACCOMPANIED BY A PLUME OF PACIFIC MOISTURE. THIS SHOULD PUT THE AREA IN A FAVORABLE REGION TO SEE ANOTHER ROUND OF SHOWERS TUESDAY AFTERNOON AND NIGHT. AS THE UPPER LOW SINKS FURTHER SOUTH TO NEAR POINT CONCEPTION BY WEDNESDAY AFTERNOON THE PROXIMITY OF THE UPPER LOW AS WELL AS A PLUME OF PACIFIC MOISTURE STREAMING INTO THE AREA SHOULD HELP TO INCREASE THE CHANCES FOR SHOWERS TO OCCUR...AND POSSIBLY MORE A STEADIER STRATIFORM TYPE PRECIPITATION EVENT IN THE MOJAVE DESERT. WITH PLENTY OF CHILL AIR ACROSS THE REGION SNOW LEVELS WILL REMAIN QUITE LOW ALLOWING FOR SNOW TO FALL IN AREAS THAT DO NOT OFTEN SEE IT. ONE ISSUE REMAINS JUST HOW FAR NORTHWEST THE MAIN MOISTURE PLUME GETS AS NORTHWEST PARTS OF THE CWFA MAY NOT SEE MUCH IF ANY PRECIP. IN LAS VEGAS...THERE COULD BE THE POTENTIAL ONCE AGAIN FOR SNOW OR A RAIN/SNOW MIX ON WEDNESDAY AS MODEL FORECAST SOUNDINGS SUGGEST P-TYPE COULD BE AN ISSUE. AGAIN THE ISSUE OF EVAPORATIONAL COOLING COULD COME INTO PLAY AS WELL ENHANCING THE PROSPECTS FOR SNOW OR A RAIN/SNOW MIX. WINTER WEATHER PRODUCTS MAY BE NEEDED FOR PARTS OF THE AREA AS THE MOISTURE SUPPLY WILL BE ENOUGH TO SUPPORT ACCUMULATING SNOW IN AT LEAST THE HIGHER PORTIONS OF THE MOJAVE DESERT. BY WEDNESDAY NIGHT THE SYSTEM FINALLY EXITS TO THE EAST AND A DRIER NORTHWEST FLOW TAKES OVER FOR THURSDAY. THE GENERAL CONSENSUS FROM THE OPERATIONAL MODELS AND GFS ENSEMBLES WERE IN DECENT AGREEMENT TO SUPPORT LOWERING POPS SHARPLY AND BRIGHTENING SKIES SOME BUT IT SHOULD STILL REMAIN BELOW NORMAL WITH A SUBTLE RISE IN TEMPS. NEVERTHELESS WE SHOULD CATCH A BREAK FROM THE CLOUDS AND SHOWERS LATER IN THE WEEK. ANOTHER SYSTEM MAY DROP DOWN FROM THE NORTH BY NEXT WEEKEND BUT MODELS REMAIN IN DISAGREEMENT WITH JUST HOW FAR SOUTH IT GETS OR WHEN IT MAY EVEN SHOW UP. && FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...WINDS WILL BE THE MAIN HAZARD TODAY WITH MECHANICAL TURBULENCE DUE TO THE STRONG WINDS ALOFT AND MOUNTAIN WAVE POTENTIAL WILL EXIST TO THE LEE OF MOUNTAINS. IN THE OWENS VALLEY...GUSTY NORTH WINDS THIS EVENING OF 30-40 KTS WILL LESSEN BY AROUND 6Z SUN. IN THE MOJAVE DESERT...GUSTY WEST TO SOUTHWEST WINDS IN EXCESS OF 35 KTS WILL OCCUR WITH THE STRONGEST GUSTS EXCEEDING 50 KTS. BLOWING DUST IS EXPECTED TO CONTINUE INTO EARLY TONIGHT AND REDUCE VSBY. WINDS ARE EXPECTED TO LESSEN AREAWIDE THIS EVENING FROM WEST TO EAST AND BECOME LIGHT AND VARIABLE TOWARDS DAYBREAK TOMORROW. SHSN ACCOMPANIED BY LOW CIGS AND MOUNTAIN OBSCURATIONS IN LINCOLN AND NORTHERN MOHAVE COUNTY TONIGHT INTO TOMORROW MORNING. WINDS WILL THEN BECOME SOUTHWEST TOMORROW AFTERNOON AHEAD OF THE NEXT SYSTEM WHICH WILL BRING THE POTENTIAL FOR CIGS BELOW 5K FEET AND SHOWERS TO THE AREA LATE SUNDAY NIGHT INTO MONDAY MORNING. MOUNTAIN OBSCURATIONS ARE POSSIBLE AND SNOW LEVELS WILL BE QUITE LOW ALLOWING FOR THE POTENTIAL OF LOW ELEVATION SNOW. ANOTHER SYSTEM LOOKS TO MOVE IN WEDNESDAY WITH ANOTHER CHANCE FOR LOW CIGS AND SHOWERS WITH YET ANOTHER CHANCE FOR MANY LOW ELEVATIONS TO SEE SNOW. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY NIGHT FOR NVZ018-019. WIND ADVISORY UNTIL MIDNIGHT PST TONIGHT FOR NVZ016-017-020>022. AZ...WIND ADVISORY UNTIL 1 AM MST SUNDAY FOR AZZ001>003-036. CA...WIND ADVISORY UNTIL MIDNIGHT PST TONIGHT FOR CAZ524>527. WIND ADVISORY UNTIL 8 PM PST THIS EVENING FOR CAZ520. && $$ JENSEN/ADAIR/STACHELSKI HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 733 PM MST SAT DEC 13 2008 .UPDATE... NO CHANGES MADE TO ONGOING HEADLINES. MADE A FEW CHANGES TO THE DETAILS FOR WINTER STORM TONIGHT AND WINDS THROUGH SUNDAY. ALSO USED OPPORTUNITY TO TWEAK MEDIUM RANGE FORECAST MONDAY NIGHT INTO WEDNESDAY BY RAISING POPS ACROSS THE NORTH AND WEST. THE LATEST SURFACE AND UPPER AIR ANALYSIS SHOW THE ARCTIC FRONT APPROACHING THE NW PLATEAU WITH THE MID LEVEL VORTICITY AXIS FOLLOWING SUIT. THE NEWEST 00Z NAM/RUC SHOW SNOW WILL DEVELOP QUICKLY AFTER 1 AM ACROSS THE WEST SLOPES OF THE CHUSKAS...SAN JUANS...JEMEZ...AND SANGRES THEN SPREAD SOUTHEAST THROUGH DAYBREAK BEFORE DISSIPATING TO SHOWERS DURING THE AFTERNOON. SNOW AMOUNTS OF 5 TO 10 INCHES LOOK ON TARGET OVER THE NORTHERN MOUNTAINS...WITH ADVISORY LEVELS OVER NMZ001-003-008-010-014. WINDS WILL ALSO BE PROBLEMATIC OVER THE HIGHER TERRAIN WITH GUSTS UP TO 65 MPH NOT OUT OF THE QUESTION ALONG THE CENTRAL MOUNTAIN CHAIN INTO SUNDAY. UTILIZED THE METMOS TEMPERATURE CURVE FOR SUNDAY AS HIGHS WILL LIKELY BE EARLY IN THE DAY ALONG AND NORTH OF I40 BEFORE TEMPS TUMBLE IN THE AFTERNOON. THIS FIRST SYSTEM STILL APPEARS TO BE JUST AN APPETIZER BEFORE A POSSIBLE MAJOR SNOW EVENT DEVELOPS MONDAY NIGHT THROUGH THURSDAY ACROSS THE NORTH AND WEST. GUYER && .PREV DISCUSSION...304 PM MST SAT DEC 13 2008... A 150 KT JET CONTINUES TO DIVE SOUTHEASTWARD PARALLEL TO THE WESTERN COAST WITH A BROAD TROUGH TAKING SHAPE OVER THE INTER MOUNTAIN WEST. SPEEDS AROUND THE BASE OF THIS FEATURE ARE UPWARDS OF 125 KT INTO NORTHWESTERN NEW MEXICO WHILE WHITE SANDS AND TUCUMCARI WIND PROFILERS REVEAL SPEEDS AOA 50 KT AT H7 AND ABOVE. SURFACE OBS ARE INDICATING THAT WINDS ARE JUST A FEW KNOTS SHY OF HIGH WIND CRITERIA ACROSS SOME CENTRAL MOUNTAIN CHAIN LOCALES...BUT IT IS QUITE WINDY NONETHELESS. ONLY A FEW RADAR ECHOES ARE EVIDENT OVER NORTH CENTRAL PORTIONS OF THE STATE...BUT THIS WILL CHANGE AND INCREASE AS APPROACHING TROUGH AXIS FORCES ENERGY INTO THE WESTERN AND NORTHERN PORTIONS OF THE CWA TONIGHT. FORECAST MODELS ARE IN GOOD AGREEMENT AND CONSENSUS FOR THE MOST PART...THUS FOCUS HAS BEEN ON HIGHLIGHTS/HAZARDS AND GENERAL IMPACTS OF THIS FIRST STORM THROUGH SUNDAY AND SUBSEQUENT AFTERSHOCK STORMS TRAILING INTO THE FIRST AND MIDDLE PARTS OF THE WORK WEEK. BEST VORTICITY ADVECTION WILL OCCUR AFTER SUNSET ACROSS NORTHWESTERN SECTIONS OF THE STATE WHERE PRECIP WILL BECOME MORE WIDESPREAD. SNOW LEVELS WILL LOWER FROM ROUGHLY 7500 FEET DOWN TO VALLEY FLOORS BY EARLY MORNING...THEREFORE ZONES 001 AND 003 WILL KEEP ADVISORIES POSTED FOR GENERALLY 1 TO 3 INCHES OF ACCUMULATION BY LATE SUNDAY. OTHER WINTER STORM WARNING AND ADVISORY SEGMENTS WILL ALSO REMAIN IN TACT AS IS. OROGRAPHICALLY ENHANCED DYNAMICS STILL LOOK TO FAVOR WESTERN SLOPES OF NORTHWESTERN MOUNTAINS...ALTHOUGH SANGRES ARE EXPECTED TO PICK UP SUFFICIENT AMOUNTS FOR WARNING. WITH LITTLE CHANGE IN H7 WIND FLOW...STRONG WINDS WILL ALSO KEEP THINGS INTERESTING WITH VISIBILITY REDUCTIONS. WINDS WILL BE STRONGEST MOSTLY ALONG RIDGE TOPS IN CENTRAL TO WESTERN AREAS OF THE STATE...HOWEVER LESS CLOUD COVER AND BETTER MIXING WILL KEEP THINGS WINDY IN THE EASTERN PLAINS. WIND ADVISORY MAY NEED TO BE RECONSIDERED FOR CENTRAL RIO GRANDE VALLY TOMORROW DUE TO CLOUD COVER AND LESS MIXING...HOWEVER ANY SHOWER ACTIVITY WOULD QUICKLY TRANSFER MOMENTUM ALOFT DOWN TO THE SURFACE. WILL LET NEXT SHIFT MAKE THE FINAL CALL. BY SUNDAY NIGHT THE FOCUS TURNS MORE OROGRAPHIC AS INITIAL PULSE EXITS THE AREA. THINGS QUICKLY RAMP BACK UP BY MID DAY MONDAY AS NEXT TROUGH AXIS ROTATES THROUGH THE BROADER FEATURE. THIS POSES AN INTERESTING DILEMMA REGARDING THE EXPIRATION TIME OF THE WINTER STORM ADVISORY/WARNING. GUT FEELING IS THAT THE BEST AND LEAST CONFUSING METHOD WILL BE TO ALLOW THE CURRENT WSW PRODUCT TO EXPIRE SUNDAY AFTERNOON...AND ALTHOUGH SOME ADDITIONAL LIGHT ACCUMULATIONS COULD OCCUR SUNDAY NIGHT IN HIGHEST TERRAIN...A NEW AND SEPARATE HAZARD PRODUCT WILL PROBABLY NEED TO BE ISSUED FOR SECOND UPCOMING STORM FOR MONDAY INTO TUESDAY. HAVE ONLY MADE MINOR TWEAKS TO THE EXTENDED FORECAST...MOSTLY IN THE NORTHEAST WHERE TEMPERATURES WERE LOWERED SOME. UNSETTLED PATTERN LOOKS TO CONTINUE INTO THURSDAY BEFORE A QUICK LIVED DRIER SLUG OF WEST SOUTHWESTERLY FLOW SETS UP. BY NEXT SUNDAY ADDITIONAL ENERGY MIGRATES INTO THE SOUTHWEST WITH ELEVATED PRECIPITATION CHANCES RETURNING. 52 .AVIATION... STRONG TO VERY STRONG WEST AND SOUTHWEST WINDS...MORE OFTEN THAN NOT...WILL CONTINUE THROUGH SUNDAY ALONG AND EAST OF THE CENTRAL MT CHAIN...WITH SOMEWHAT LOWER BUT STILL BRISK WINDS WEST OF THE CENTRAL MT CHAIN. SOME MT WAVE ACTIVITY IS LIKELY TO CONTINUE THROUGH THE PERIOD TO THE EAST OF MOST OF THE HIGHER RANGES OF THE STATE...BUT WILL LIKELY BE MOST PRONOUNCED TO THE EAST OF THE CENTRAL MT CHAIN. THE STRONGEST SURFACE WINDS OF 25 TO NEARLY 40 KTS WITH SOME GUSTS BETWEEN 40 AND 55 KTS...EVEN STRONGER ALOFT...SHOULD BE JUST TO THE LEE OF THE CENTRAL MT CHAIN INTO MID EVE OR SO...THEN IT MAY SUBSIDE A LITTLE ONLY TO INCREASE AFTER MIDNIGHT IN A MORE SPOTTY AND ERRATIC FASHION COMPARED WITH THIS AFTN. DURING THE LATE MORN AND AFTN SUNDAY...THE STRONGER WINDS SHOULD BECOME MORE WIDESPREAD AGAIN. AREAS OF RAIN AND SNOW WILL SPREAD INTO THE W AND NW LATE TONIGHT AND EARLY SUNDAY...SPREADING EASTWARD ACROSS THE REST OF N AND W WITH SOME OF IT MAKING IT INTO CENTRAL AND NORTHEAST NM. CIGS WILL FREQUENTLY BE IN THE IFR AND MVFR RANGE VERY LATE TONIGHT THROUGH AT LEAST EARLY AFTN SUNDAY W OF A LINE FROM ROUGHLY KRTN TO SOCORRO...WHILE ELSEWHERE VFR CONDITIONS SHOULD DOMINATE THOUGH SOME PATCHY BLOWING DUST IS LIKELY TO THE E OF THE CENTRAL MT CHAIN. 43 NEXT AVIATION DISCUSSION SCHEDULED FOR 10Z. 43 .FIRE WEATHER... UNSETTLED WEATHER WILL CONTINUE FOR THE FORESEEABLE FUTURE...THOUGH A 2 OR 3 DAY BREAK IS POSSIBLE BETWEEN FRI AND SUN OF NEXT WEEK. MAJOR SNOW ACCUMULATIONS WILL BE POSSIBLE ACROSS THE HIGHER TERRAIN...ESPECIALLY W AND N NM...WHERE 1 1/2 TO POSSIBLY 3 OR 4 FT OF SNOW IS POSSIBLE. THE HIGHER END AMOUNTS SHOULD BE LIMITED TO HIGH TERRAIN NEAR THE CO AND AZ STATE LINE. WIND WILL BE THE OTHER STORY THROUGH THE NEXT 2 DAYS OR SO. STRONGEST WINDS WILL BE FROM THIS LATE AFTN INTO SUNDAY AFTERNOON...FAVORING THE CENTRAL MTN CHAIN AND POINTS JUST TO THE EAST. GUSTS BETWEEN 45 AND 60 MPH WILL BE POSSIBLE THERE. HUMIDITY LEVELS WILL TREND HIGHER ON SUNDAY AND MONDAY AND REMAIN THAT WAY THROUGH MOST OF NEXT WEEK. 43 && .PRELIMINARY POINT TEMPS/POPS UPDATE... FARMINGTON...................... 31 32 20 35 / 60 60 10 40 GALLUP.......................... 29 31 18 35 / 60 70 20 50 GRANTS.......................... 30 34 17 37 / 50 60 10 30 GLENWOOD........................ 35 46 27 48 / 20 60 20 20 CHAMA........................... 24 26 1 27 / 90 80 20 50 LOS ALAMOS...................... 27 33 17 35 / 30 50 20 50 RED RIVER....................... 23 24 3 23 / 70 90 20 30 TAOS............................ 27 30 13 31 / 50 60 10 30 SANTA FE........................ 31 35 18 38 / 20 40 10 50 SANTA FE AIRPORT................ 30 37 20 37 / 20 40 10 50 ESPANOLA........................ 24 41 19 41 / 30 40 10 30 ALBUQUERQUE HEIGHTS............. 36 43 29 43 / 10 20 10 40 ALBUQUERQUE VALLEY.............. 32 44 24 46 / 10 20 10 40 ALBUQUERQUE FOOTHILLS........... 33 42 24 42 / 10 20 10 40 ALBUQUERQUE WEST MESA........... 33 44 25 47 / 10 20 10 40 SOCORRO......................... 31 56 27 49 / 5 20 5 10 SANDIA PARK/CEDAR CREST......... 27 36 17 38 / 10 30 10 50 MORIARTY/ESTANCIA............... 26 42 21 40 / 10 30 10 40 CARRIZOZO....................... 40 55 30 44 / 5 20 5 10 RUIDOSO......................... 35 48 28 42 / 5 20 5 20 RATON........................... 31 42 11 30 / 10 20 10 20 LAS VEGAS....................... 34 39 14 32 / 10 20 10 30 ROY............................. 34 43 18 31 / 10 20 5 20 CLAYTON......................... 35 42 13 28 / 5 10 5 10 SANTA ROSA...................... 39 54 23 43 / 5 20 5 10 TUCUMCARI....................... 43 53 20 36 / 0 10 5 10 FORT SUMNER..................... 37 59 23 41 / 5 10 5 5 CLOVIS.......................... 42 60 20 37 / 0 5 5 5 PORTALES........................ 40 61 19 40 / 0 5 5 5 ROSWELL......................... 43 67 34 46 / 0 0 5 5 && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 PM MST SUNDAY FOR THE FOLLOWING ZONES...NMZ001-003. WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR THE FOLLOWING ZONES...NMZ002-004. WIND ADVISORY UNTIL 5 PM MST SUNDAY FOR THE FOLLOWING ZONES... NMZ006-007-009-013-015-018>021. HIGH WIND WARNING UNTIL 5 PM MST SUNDAY FOR THE FOLLOWING ZONES... NMZ005-010>012-016-017-026. WINTER WEATHER ADVISORY UNTIL 5 PM MST SUNDAY FOR THE FOLLOWING ZONES...NMZ008-014. && $$ GUYER nm AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1255 PM EST SUN DEC 14 2008 .SYNOPSIS... RETURN FLOW ON THE BACK SIDE OF THE RECENTLY DEPARTED SURFACE HIGH WILL INCREASE LOW LEVEL MOISTURE ACROSS CENTRAL NORTH CAROLINA THROUGH TONIGHT...RESULTING IN AN INCREASE IN CLOUD COVER...AND A CHANCE FOR LIGHT RAIN BY MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY... THE LATEST SURFACE ANALYSIS SHOWED SURFACE HIGH PRESSURE CONTINUING TO EXTEND SOUTHWEST INTO CENTRAL NORTH CAROLINA FROM THE MID-ATLANTIC. UPPER-AIR ANALYSIS SHOWED MOISTURE AT 850MB GRADUALLY MOVING NORTH TOWARD CENTRAL NORTH CAROLINA...ALTHOUGH KGSO AT 12Z WAS ON THE SOUTHERN EDGE OF AN AREA OF VERY DRY AIR AT THAT LEVEL. THE AIR MASS WAS DRY ABOVE 850MB OVERALL...WITH HIGH-LEVEL MOISTURE MOVING OVER THE LOW AMPLITUDE UPPER RIDGE. AMDAR SOUNDINGS FROM KRDU SHOWED GRADUAL WARM-AIR ADVECTION TAKING PLACE FROM 850MB THROUGH 700MB. ISENTROPIC DESCENT ON THE 295K SURFACE THIS MORNING WILL TRANSITION TO WEAK ISENTROPIC LIFT THIS AFTERNOON AS FORECAST BY THE LATEST NAM...WITH GOOD 850MB THETA-E ADVECTION TODAY ESPECIALLY IN WESTERN ZONES AHEAD OF THE LEFT EXIT REGION OF A 300MB 85-100KT JET THAT MOVES NEAR CENTRAL NORTH CAROLINA LATE IN THE DAY. MID-LEVELS STAY DRY...AND THOUGH LOW-LEVEL DIVERGENCE REMAINS MODERATE TO STRONG...INCREASING DIVERGENCE ALOFT PROVIDES FOR MODEST LIFT MAINLY IN WESTERN ZONES AS FORECAST BY BOTH THE NAM AND THE RUC LATE TODAY. POTENTIAL FOR DRIZZLE APPEARS LIMITED BASED ON THE LACK OF APPARENT LOW-LEVEL CONVERGENCE BUT WILL CONTINUE WITH A SLIGHT CHANCE OF IT LATE IN FAR WESTERN COUNTIES BASED ON THE MOISTURE ADVECTION AND WEAK ISENTROPIC LIFT. ELSEWHERE...WHILE SKIES SHOULD BECOME RATHER CLOUDY IN THE WEST DURING THE DAY AND BE MOSTLY CLOUDY WITH PATCHES OF SUN CENTRAL... PARTLY SUNNY CONDITIONS IN THE COASTAL PLAIN WITH A MIX OF STRATOCU AND HIGH-LEVEL CLOUDS SHOULD BECOME PREDOMINANTLY MOSTLY CLOUDY BY LATE IN THE DAY. BREAKS IN THE CLOUDS MAKE HIGH TEMPERATURES A LITTLE TRICKY EVEN WITH THE GOOD MOISTURE ADVECTION... BUT WITH THE SLOW MORNING RISE AND AVAILABLE CLOUD COVER PRESENT OPTED TO LOWER TEMPERATURES ON AVERAGE A COUPLE OF DEGREES. TONIGHT...EXPECT MOSTLY CLOUDY TO OVERCAST CONDITIONS ACROSS THE AREA AS SCATTERED TO OVERCAST LOW STRATUS ASSOC/W WARM ADVECTION PERSISTS...AND MID/UPPER LEVEL CLOUD COVER STREAMS INTO THE AREA VIA WSW/SW FLOW ALOFT. AGAIN...THE OVERCAST LOW STRATUS SHOULD REMAIN CONFINED PRIMARILY TO THE FAR WESTERN PIEDMONT...WITH SCATTERED TO BROKEN LOW STRATUS ELSEWHERE. WILL CONTINUE WITH ONLY PATCHY DRIZZLE IN THE FAR WESTERN PIEDMONT...WITH A SLIGHT CHANCE OF DRIZZLE EXTENDING EAST TOWARD THE TRIANGLE/FAY AREA THROUGH SUNRISE. ALTHOUGH NO MEASURABLE PRECIP IS EXPECTED...A HUNDREDTH OR TWO CANNOT BE COMPLETELY RULED OUT IN THE TRIAD. WITH EXTENSIVE CLOUD COVER...IN ADDITION TO ONGOING WARM ADVECTION...EXPECT RELATIVELY MILD LOWS TONIGHT...RANGING FROM THE LOWER/MID 40S IN THE TRIAD...NOT MUCH OF A DEPARTURE FROM EXPECTED TEMPERATURES LATE IN THE DAY...TO THE UPPER 40S TO LOWER 50S IN THE EAST/SE COASTAL PLAIN. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 305 AM SUNDAY... UPPER FLOW DURING THIS PERIOD IS A GENERAL W TO SW FLOW AT MID AND UPPER LEVELS WITH THE POLAR JET CONFINE NORTH OF THE AREA AND CENTRAL NC ON THE PERIPHERY OF THE STORM TRACK TO THE NORTH. MAIN WEATHER FEATURE THIS PERIOD WILL BE A COLD FRONT THAT MOVES INTO THE APPALACHIANS ON MON NIGHT. LATEST NAM/GFS/SREF GUIDANCE IS CONSISTENT IN BRINGING THE FRONT ACROSS CENTRAL NC AROUND DAYBREAK ON TUESDAY AND THEN STALLING IT ACROSS SOUTHERN NC ON TUESDAY AFTN AND TUESDAY NIGHT BEFORE LIFTING IT RAPIDLY NORTH ON WEDNESDAY. MAINLY OVERCAST SKIES ARE EXPECTED ON MONDAY WITH A SOUTHERLY FLOW AND ISENTROPIC LIFT PRODUCING SOME SPOTTY LIGHT RAIN. CHANCES OF RAIN INCREASES LATE IN THE DAY AS BOTH THE NAM/GFS SHOW A SHORT WAVE RIDING ACROSS THE MISSISSIPPI AND TENNESSEE VALLEYS TOWARD SUNSET. WILL INCLUDE LOW CHANCE POPS IN THE W MON AND SLIGHT CHC IN THE EAST. EVEN WITH CONSIDERABLE CLOUDINESS A SOUTHERLY FLOW WILL DRIVE WARMER TEMPS INTO THE AREA. HIGH TEMPS ON MON WILL RANGE IN THE LOWER 60S IN THE TRIAD TO LOWER 70S ACROSS THE SOUTHERN COASTAL PLAIN. TEMPS SHOULD NOT FALL MUCH ON MONDAY NIGHT WITH MAINLY CLOUDY SKIES AND A LIGHT BUT STEADY SOUTHERLY WIND. THE COLD FRONT MOVES INTO THE TRIAD AREA AFTER MIDNIGHT BUT RECENT STUDIES INDICATE THAT LOW TEMPS ARE USUALLY WARMER THEN EXPECTED WITH NOCTURNAL COLD FRONTAL PASSAGES. LOW TEMPS WILL RANGE IN THE LOWER 50S IN THE TRIAD TO UPPER 50S IN THE SOUTHERN COASTAL PLAIN. THE COLD FRONT WILL PROVIDE AN ADDITIONAL FOCUS FOR PRECIPITATION ON MONDAY NIGHT. INCREASED POPS TO NEAR 50 IN THE TRIAD TO AROUND 30 PERCENT IN THE SOUTHERN COASTAL PLAIN WHERE UPPER SUPPORT IS WEAKER. THE COLD AIR BEHIND THE FRONT IS RATHER SHALLOW AND THERE IS NOT A GREAT SOUTHWARD PUSH WITH THE COLD AIR AS THE PARENT HIGH IS TRANSIENT AND WEAKENS WITH TIME. THE BULK OF THE COLD AIR REMAINS NORTH OF US 64...ESPECIALLY NEAR THE VA/NC BORDER. WHILE THE LOW LEVELS COOL NOTICEABLY...A SOUTHWESTERLY FLOW CONTINUES JUST A FEW THOUSAND FEET RESULTING IN A FAIR AMOUNT OF CLOUD COVER AND A CHANCE OF LIGHT RAIN...ESPECIALLY ACROSS NORTHERN PORTIONS OF FORECAST AREA. WILL INCLUDE A NON DIURNAL TEMP CURVE ON TUESDAY AS COLD AIR MOVES INTO THE NORTHERN PORTION OF FORECAST AREA AS TEMPS REMAIN STEADY OR FALL SLIGHTLY ON TUES. HIGH TEMPS WILL RANGE IN THE LOWER 50S NEAR THE VA BORDER TO MID 60S ACROSS THE SOUTHERN PIEDMONT AND SOUTHERN COASTAL PLAIN. MAINLY CLOUDY SKIES WILL CONTINUE INTO TUESDAY NIGHT WITH LOWS RANGING IN THE MID TO UPPER 40S. THE COLD FRONT WILL LIFT NORTH ON WEDNESDAY AND TEMPERATURES WILL REBOUND INTO THE LOWER 60S TO AROUND 70 DEGREES. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 325 AM SUNDAY... RIDGE ACROSS THE SOUTHEAST DOMINATES THE WEATHER THROUGH THIS PERIOD WITH A SW FLOW ALOFT. HPC GUIDE NOTES THAT THE GFS APPEARS TOO FAST IN BRINING ANOTHER SYSTEM INTO THE OHIO VALLEY AND APPALACHIANS ON FRI/SAT...THEY PREFER A SLOWER MORE ECMWF LIKE SOLUTION. THE RESULT WILL BE TEMPS THAT AVERAGE SLIGHTLY ABOVE NORMAL DURING MOST OF THE PERIOD. FRONTAL PASSAGE EXPECTED LATE FRIDAY OR EARLY SATURDAY. LINGERING LOW CHC POPS WILL CONTINUE EARLY ON THURSDAY WITH NO POPS INCLUDED ON FRI AND SAT. TRENDS SUGGEST THAT THE COLD AIR SURGE BEHIND THIS FRONT MAY BE COLDER THEN CURRENT FORECAST BUT WILL HOLD OFF MAKING ANY SIGNIFICANT CHANGES TO TEMP FORECAST. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 1255 PM SUNDAY... VFR CEILINGS...WITH AREAS OF MVFR CEILINGS...WILL GRADUALLY LOWER TO PREDOMINANTLY IFR CEILINGS IN THE TRIAD AND MVFR ELSEWHERE IN GOOD LOW-LEVEL MOISTURE ADVECTION AND INCREASING SOUTHERLY FLOW. FOR TONIGHT...CLOUD HEIGHTS ARE MORE DIFFICULT TOWARD KFAY AND KRWI WHERE BOTH THE NAM AND THE GFS SUGGEST LOW-LEVEL MOISTURE ADVECTION WILL NOT BE AS STRONG AS FARTHER WEST TOWARD THE TRIAD. THERE COULD BE A PERIOD OF IFR CEILINGS ESPECIALLY AT KFAY...BUT CURRENTLY BELIEVE THE PREDOMINANT CHARACTER OF CEILINGS WILL BE MVFR OVERNIGHT THERE. GFS AND NAM BUFR SOUNDINGS AND LOW-LEVEL WIND SHEAR CRITERIA SUGGEST MARGINAL CONDITIONS FOR LLWS BUT BASIC THRESHOLDS ARE MET EXCEPT AT KFAY...WHERE THE 925MB WINDS ARE LIGHTER AND MODEL SOUNDINGS SHOW FORECAST WINDS TO AROUND 25KT AT 1500FT OR SO OVERNIGHT. LLWS CONDITIONS SHOULD DIMINISH AT REMAINDER OF TAF SITES MONDAY MORNING AS 925MB WINDS RELAX...TO 20-25KT BY 18Z MONDAY. ANY PRECIPITATION SHOULD BE LIGHT...AND THOUGH THERE COULD BE A BRIEF SHOWER OR SPRINKLE ANY PLACE IN CENTRAL NORTH CAROLINA...BEST CHANCES FOR THIS WILL BE TOWARD THE TRIAD. TAFS THERE SHOW LENGTHY PERIOD OF -SHRA BUT BELIEVE THE BETTER CHANCES WILL BE EARLY AND AGAIN LATER IN THE FM GROUP COINCIDENT WITH PERIODS OF BETTER MID-LEVEL MOISTURE AS FORECAST BY THE NAM AND GFS. BEYOND THE 18Z TAF PERIOD...IN THE MOIST AIR AHEAD OF A PAIR OF COLD FRONTS...PERIODS OF LOW CLOUDS WILL OCCUR. MOST WIDESPREAD LOW CLOUD COVERAGE IS EXPECTED LATE TUESDAY AND TUESDAY NIGHT AS HIGH PRESSURE WEDGES IN FROM THE NORTH WITH LOW-LEVEL MOISTURE REMAINING HIGH... COINCIDENT WITH AN INITIAL FRONT THAT MOVES THROUGH AND WEAKENS. A STRONGER COLD FRONT FOLLOWS LATE IN THE WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/VINCENT SHORT TERM...BLAES LONG TERM...BLAES AVIATION...DJF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1225 PM EST SAT DEC 13 2008 .SYNOPSIS... HIGH PRESSURE WILL SETTLE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON. AS THE SURFACE HIGH MOVES OFFSHORE TONIGHT...A SOUTHERLY RETURN FLOW WILL DEVELOP OVER THE AREA...BRINGING INCREASED CLOUD COVER...WARMER TEMPERATURES...AND A CHANCE FOR LIGHT RAIN BY MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM SATURDAY... CHANGES NEARLY INSIGNIFICANT THIS MORNING...SURFACE HIGH PRESSURE HAS MIGRATED NORTHEASTWARD INTO NE ALABAMA...WITH SURFACE WINDS OVER THE NC BECOMING MORE NORTHERLY. THE 12Z RAOB FROM GSO FEATURED A STRONG SUBSIDENCE INVERSION WITH ITS BASE JUST ABOVE 850MB. VERY DRY AIR JUST ABOVE THE INVERSION WAS QUITE DRIER THAN FORECAST IN BUFR SOUNDINGS. THE CIRRUS SHIELD AHEAD OF AN UPPER LEVEL SHORTWAVE MOVING OVER THE CENTRAL PLAINS IS JUST BEGINNING TO REACH THE APPALACHIANS. ONLY CHANGES WILL BE TO LOWER TEMPS AN DEWPOINTS JUST A TAD. THE 12Z OBSERVED THICKNESS AT GSO WAS 1284M...3 METERS LOWER THAN FORECAST...WHICH SUGGEST HIGHS A DEGREE OR TWO COOLER THAN FORECAST. WITH INCREASING CLOUD COVER AND CAA (ALTHOUGH WEAKENING)...THIS SEEMS REASONABLE. WILL ALSO LOWER DEWPOINTS MINIMALLY...SINCE MUCH DRIER AIR THAN FORECAST ABOVE THE SUBSIDENCE INVERSION SHOULD KEEP DEWPOINTS IN THE MID TO UPPER TEENS THROUGH DAYTIME MIXING. -SMITH PREVIOUS DISCUSSION... SFC ANALYSIS THIS MORNING SHOWED 1029 MB HIGH PRESSURE CENTERED OVER ALABAMA...WITH A SFC RIDGE AXIS EXTENDING NORTH INTO THE OH VALLEY. A SFC TROUGH AXIS WAS LOCATED ACROSS THE WESTERN CAROLINAS. ALOFT... WV IMAGERY AND RUC MODEL DATA SHOW A POTENT SHORTWAVE CURRENTLY TRAVERSING THE AREA. TODAY AND TONIGHT: STRONG SUBSIDENCE BEHIND THE POTENT SHORTWAVE CROSSING THE AREA EARLY THIS MORNING WILL HELP SFC HIGH PRESSURE BUILD EAST OVER THE CAROLINAS THIS AFTERNOON. THE ~1030 MB SFC HIGH IS EXPECTED TO BE CENTERED DIRECTLY OVER CENTRAL NC AT ROUGHLY 18Z...MOVING OFFSHORE THE MID-ATLANTIC BY 12Z SUNDAY. WITH SUBSIDENCE AT THE SFC AND ALOFT...EXPECT SUNNY SKIES THROUGH EARLY/MID AFTERNOON. ABUNDANT SUNSHINE WILL NOT LAST TOO LONG...HOWEVER...AS UPPER LEVEL MOISTURE ASSOC/W A DEEPENING SFC LOW IN THE LEE OF THE ROCKIES STREAMS EASTWARD TOWARD THE CAROLINAS VIA A 75-100 KT WESTERLY JET. FCST SOUNDINGS SHOW BROKEN TO OVERCAST MID/UPPER LEVEL CEILINGS ACROSS THE ENTIRE AREA BY ROUGHLY 00Z THIS EVENING. AS SUCH...WILL SHOW INCREASING CLOUD COVER FROM WEST TO EAST AFTER 18Z...WITH MOSTLY CLOUDY SKIES FROM SUNSET THROUGH AT LEAST MIDNIGHT. FCST SOUNDINGS HINT AT SOME CLEARING AFTER MIDNIGHT...AND WILL SHOW A DECREASE TO PARTLY CLOUDY FROM MIDNIGHT TO SUNRISE. FOR TEMPS...MOS GUIDANCE AGREES PRETTY WELL (ALBEIT A FEW DEGREES HIGHER) WITH THE 1000-850 MB THICKNESSES OFF THE GFS/NAM...AND WILL COMPROMISE BETWEEN MOS GUIDANCE AND THE THICKNESSES AND SHOW A RANGE FROM THE MID 40S IN THE NORTHEAST COASTAL PLAIN TO THE UPPER 40S TO AROUND 50F IN SOUTHERN AND WESTERN PORTIONS OF THE AREA. IF EXTENSIVE MID/UPPER LEVEL CLOUDS ARRIVE BY EARLY AFTERNOON IN THE WEST...THIS MAY BE TOO WARM IN THE WEST BY A DEGREE OR TWO. LOWS TONIGHT SOMEWHAT DIFFICULT WITH PERVASIVE MID/UPPER LEVEL CLOUD COVER EXPECTED THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. LOWS WILL ENTIRELY DEPEND ON WHICH LOCATIONS HAVE THE OPPORTUNITY TO RADIATE WELL FOR SEVERAL HOURS BEFORE SUNRISE. AT THIS TIME...WILL BLEND CLOSE TO WHAT MOS GUIDANCE IS SUGGESTING...WITH A RANGE OF 27-30F ACROSS THE AREA DUE TO THE COOL/DRY AIRMASS IN PLACE ASSOC/W THE SFC HIGH. -VINCENT && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY... SUNDAY: SFC HIGH PRESSURE CONTINUES MOVING FURTHER OFFSHORE DURING THE DAY SUNDAY...ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP ACROSS THE CAROLINAS. THIS WILL CAUSE WARM ADVECTION TO STRENGTHEN OVER THE AREA BY OR SHORTLY AFTER SUNRISE...ALLOWING ENOUGH MOISTURE/LIFT FOR LOW STRATUS TO DEVELOP. WHILE GFS/NAM FCST SOUNDINGS AGREE THAT THE WESTERN PIEDMONT WILL BE COMPLETELY OVERCAST IN LOW STRATUS BY 15-18Z...THEY ARE MORE AMBIGUOUS TOWARD THE TRIANGLE AND NORTHEAST COASTAL PLAIN. WILL SHOW SKIES BECOMING MOSTLY CLOUDY TO OVERCAST IN THE FAR WESTERN PIEDMONT BY EARLY AFTERNOON WHERE AN UPSLOPE COMPONENT IN THE LOW LEVEL FLOW WILL HELP PROVIDE ADDITIONAL LIFT IN VICINITY OF THE FOOTHILLS/MOUNTAINS...WITH INCREASING CLOUD COVER (PARTLY TO MOSTLY CLOUDY) ELSEWHERE THROUGH THE DAY IN ASSOC/W PERSISTENT WARM ADVECTION. A SOMEWHAT DIFFICULT HIGH TEMP FORECAST THAT WILL ULTIMATELY DEPEND ON CLOUD COVER. 1000-850MB THICKNESSES START OUT AROUND 1310-1320M 12Z SUN...INCREASING TO 1340-1350M BY 00Z. WITH FULL SUN...THESE THICKNESSES WOULD YIELD HIGHS IN THE UPPER 50S TO NEAR 60F. WITH OVERCAST LOW CLOUD COVER...HOWEVER... HIGHS WOULD STRUGGLE TO MAKE IT OUT OF THE 40S. WILL TREND TOWARD MOS GUIDANCE...SHOWING A RANGE FROM AROUND 49-50F IN THE TRIAD TO THE UPPER 50S TO AROUND 60F IN THE SE COASTAL PLAIN. WOULD NOT BE SURPRISED TO SEE TEMPS BUST 3-5F...DEPENDING ON THE DEGREE OF CLOUD COVER ACROSS THE AREA. W/REGARD TO PRECIP CHANCES...BOTH THE GFS/NAM SHOW LIGHT QPF IN ASSOC/W WARM ADVECTION IN THE WESTERN PIEDMONT AND FOOTHILLS FROM NOON THROUGH SUNSET. HOWEVER...FCST SOUNDINGS SHOW RATHER SHALLOW MOISTURE WITH SATURATION NOT EVEN EXTENDING UP TO THE 0C ISOTHERM. IT WOULD BE TOUGH TO GET MEASURABLE PRECIP IN THE WESTERN PIEDMONT WITH THOSE TYPE OF THERMAL/MOISTURE PROFILES... AND HAVE DECIDED TO REMOVE MENTION OF A SLIGHT OR LOW CHANCE OF MEASURABLE RAIN AND REPLACE IT WITH A CHANCE OF DRIZZLE IN THE FAR WESTERN PIEDMONT BEGINNING IN THE AFTERNOON. A BETTER CHANCE FOR A FEW HUNDREDTHS OF LIGHT RAIN WILL BE FURTHER WEST IN THE FOOTHILLS / BLUE RIDGE WHERE UPSLOPE FLOW WILL ENHANCE LIFT. SUNDAY NIGHT: SOUTHERLY LOW LEVEL FLOW / WARM ADVECTION CONTINUES ON SUNDAY NIGHT AS THE GRADIENT ACROSS THE CAROLINAS REMAINS PINCHED BETWEEN STRONG HIGH PRESSURE WELL OFFSHORE THE MID-ATLANTIC AND STRONG LOW PRESSURE ACROSS THE UPPER GREAT LAKES. WITH CONTINUED WARM ADVECTION...EXPECT MOSTLY CLOUDY TO OVERCAST SKIES ACROSS THE ENTIRE AREA. CANNOT RULE OUT SOME DRIZZLE ACROSS THE SE COASTAL PLAIN...SANDHILLS...TRIANGLE AND WESTERN PIEDMONT WHERE THE BETTER SATURATION IS EXPECTED. FCST SOUNDINGS STILL SHOW RATHER SHALLOW MOISTURE WITH SATURATION NOT EVEN EXTENDING ABOVE THE 0C ISOTHERM...AND THIS IS THE REASON FOR KEEPING MEASURABLE POPS OUT OF THE FCST. DUE TO EXTENSIVE CLOUD COVER AND CONTINUED WARM ADVECTION...EXPECT MUCH MORE MODERATE LOWS THAN SAT NIGHT...AND WILL TREND CLOSE TO MOS GUIDANCE SHOWING LOWS RANGING FROM 44-50F FROM NW TO SE. MONDAY: WARM ADVECTION CONTINUES ON MONDAY...ALTHOUGH LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY BY THE AFTERNOON HOURS AS A FRONT ASSOC/W LOW PRESSURE NORTH OF THE GREAT LAKES CROSSES INTO THE TN/OH VALLEY AND APPROACHES THE SOUTHERN APPALACHIANS BY 00Z TUE. FCST SOUNDINGS SHOW A RATHER CONSIDERABLE MID-LEVEL CAP FOR ALMOST THE ENTIRE DAY MONDAY...SO ALTHOUGH TEMPS/DEWPOINTS WILL BE UNSEASONABLY WARM BY THE AFTERNOON HOURS...DO NOT EXPECT ANY SUBSTANTIAL (HEAVY) SHOWER ACTIVITY GIVEN THAT THE EQUILIBRIUM LEVEL SHOULD BE ONLY 8-10 KFT AGL. WILL ADD A SLIGHT CHANCE OF SHOWERS FOR THE AFTERNOON HOURS DURING PEAK HEATING. WILL KEEP POPS ONLY AT SLIGHT CHANCE GIVEN NO (OR VERY LITTLE) UPPER LEVEL HELP. HIGH TEMPS LOOK WAY ABOVE NORMAL WITH RATHER STRONG LOW LEVEL SOUTHERLY FLOW...IN FACT...GFS/NAM FCST SOUNDINGS SHOW AROUND 30 KT FLOW AT 925 MB...AND 35-40 KT FLOW AT 850 MB. WILL FCST HIGHS RANGING FROM THE MID 60S WEST TO THE LOWER 70S EAST/SE. IF THERE ARE ENOUGH BREAKS IN CLOUD COVER TO ALLOW MIXING EVEN IN THE LOWEST FEW KFT AGL IT COULD BE RATHER BREEZY MON AFTERNOON. FOR NOW...WILL SHOW 10-15 MPH SOUTHERLY WINDS WITH GUSTS UP TO 25 MPH. MONDAY NIGHT: THE WEAK FRONT IS EXPECTED TO MAKE IT INTO THE FOOTHILLS AND POSSIBLY THE FAR WESTERN PIEDMONT MONDAY NIGHT BEFORE STALLING OUT. NOT MUCH IN THE WAY OF LIFT ON MON NIGHT...VIRTUALLY NOTHING IN THE UPPER LEVELS...AND ONLY VERY WEAK LOW LEVEL CONVERGENCE IN THE LOWER LEVELS IN VICINITY OF THE BOUNDARY. BOTH THE GFS/NAM TRY AND SHOW LIGHT QPF OVER THE ARE MON NIGHT IN ASSOC/W THE BOUNDARY...SO HAVE DECIDED TO LEAVE A SLIGHT CHANCE OF SHOWERS IN THE FCST FOR MONDAY NIGHT. DUE TO CONTINUED SOUTHERLY FLOW AND CLOUD COVER...WILL FCST MILD LOW TEMPS IN THE LOWER/MID 50S...WHICH IS THE AVERAGE HIGH FOR THIS TIME OF YEAR! THESE VALUES ARE CLOSE TO THE MEX MOS GUIDANCE NUMBERS. -VINCENT && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... A COLD FRONT WILL APPROACH AND MOVE ACROSS THE REGION TUESDAY... STALLING SOUTH OF THE AREA TUESDAY NIGHT. WHILE THERE WILL BE A CHANCE FOR RAIN... THE MOIST LAYER IS VERY SHALLOW... SO RAIN TOTALS SHOULD REMAIN RATHER LOW. ANOTHER BOUNDARY APPROACHES THE AREA FROM THE NORTH WEDNESDAY AND LINGERS ALONG THE NORTH CAROLINA/VIRGINIA BORDER THURSDAY... UNTIL A STORM SYSTEM OVER THE CENTRAL U.S. WORKS ITS WAY EAST/NORTHEAST THURSDAY NIGHT INTO FRIDAY MORNING. HIGH PRESSURE RIDGING FROM THE FROM THE SOUTH ATLANTIC WEST ACROSS THE GULF COAST STATES WILL SLOW THE ADVANCEMENT OF THIS FRONT INTO NORTH CAROLINA UNTIL WELL INTO THE DAY FRIDAY. THUS POPS HAVE BEEN ADJUSTED FOR THE FRIDAY TIME PERIOD. HIGHS TUESDAY AND WEDNESDAY WILL BE IN THE 60S... FALLING INTO THE 50S THURSDAY AND FRIDAY. LOWS TUESDAY NIGHT AND WEDNESDAY NIGHT WILL BE IN THE 40S... THEN RANGE FROM THE MID 30S NORTHWEST TO LOWER 40S SOUTHEAST THURSDAY NIGHT. -RHJ && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... AS OF 1225 PM SATURDAY... HIGH PRESSURE AND VFR CONDITIONS ARE OBSERVED ACROSS CENTRAL NC. INCREASING UPPER LEVEL MOISTURE ADVECTION ACROSS THE AREA FROM THE WEST WILL LEAD TO MID AND HIGH LEVEL CLOUDS THIS EVENING. MEANWHILE...THE SURFACE HIGH MOVES TO THE NORTHEAST OFF AWAY FROM THE AREA...BUT RIDGING WILL CONTINUE TO EXTEND INTO THE AREA. AROUND THE PERIPHERY OF THE RIDGE...A GENTLE EAST TO SOUTHEASTERLY FLOW WILL DEVELOP THROUGH THE MORNING HOURS...PULLING MOISTURE THROUGH THE SOUTHERN AND WESTERN PIEDMONT. STRATUS WITH CEILINGS AROUND 2K FEET SHOULD DEVELOP AT GSO/INT BY THE END OF THE VALID TAF PERIOD. FORECAST SOUNDINGS SUGGEST THIS MOISTURE WILL NOT SPREAD VERY FAR EASTWARD UNTIL THE SURFACE RIDGE RETREATS FURTHER. THUS...EXPECT FAY AND RDU TO BE ONLY THE EDGE OF THE MVFR CEILINGS. ADVERSE AVIATION CONDITIONS IN MVFR/IFR CEILINGS MAY PERSIST THROUGH TUESDAY AS A COLD FRONT APPROACHES AND STALLS OUT JUST WEST OF THE AREA BY MON NIGHT. CANNOT RULE OUT ISOLD SHOWER ACTIVITY ON MONDAY. IN ADDITION... COULD SEE A PERIOD OF LOW LEVEL WIND SHEAR THREAT LATE SUNDAY NIGHT INTO MONDAY...AS WINDS AT 2KT FEET APPROACH 35-40KT BASED ON CURRENT FORECAST SOUNDINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT/SMITH SHORT TERM...VINCENT LONG TERM...RHJ AVIATION...SMITH nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 309 AM EST SAT DEC 13 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO CENTRAL NORTH CAROLINA THIS MORNING... THEN SETTLE OVERHEAD THIS AFTERNOON INTO TONIGHT. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 130 AM SATURDAY... SFC ANALYSIS THIS MORNING SHOWED 1029 MB HIGH PRESSURE CENTERED OVER ALABAMA...WITH A SFC RIDGE AXIS EXTENDING NORTH INTO THE OH VALLEY. A SFC TROUGH AXIS WAS LOCATED ACROSS THE WESTERN CAROLINAS. ALOFT... WV IMAGERY AND RUC MODEL DATA SHOW A POTENT SHORTWAVE CURRENTLY TRAVERSING THE AREA. TODAY AND TONIGHT: STRONG SUBSIDENCE BEHIND THE POTENT SHORTWAVE CROSSING THE AREA EARLY THIS MORNING WILL HELP SFC HIGH PRESSURE BUILD EAST OVER THE CAROLINAS THIS AFTERNOON. THE ~1030 MB SFC HIGH IS EXPECTED TO BE CENTERED DIRECTLY OVER CENTRAL NC AT ROUGHLY 18Z...MOVING OFFSHORE THE MID-ATLANTIC BY 12Z SUNDAY. WITH SUBSIDENCE AT THE SFC AND ALOFT...EXPECT SUNNY SKIES THROUGH EARLY/MID AFTERNOON. ABUNDANT SUNSHINE WILL NOT LAST TOO LONG...HOWEVER...AS UPPER LEVEL MOISTURE ASSOC/W A DEEPENING SFC LOW IN THE LEE OF THE ROCKIES STREAMS EASTWARD TOWARD THE CAROLINAS VIA A 75-100 KT WESTERLY JET. FCST SOUNDINGS SHOW BROKEN TO OVERCAST MID/UPPER LEVEL CEILINGS ACROSS THE ENTIRE AREA BY ROUGHLY 00Z THIS EVENING. AS SUCH...WILL SHOW INCREASING CLOUD COVER FROM WEST TO EAST AFTER 18Z...WITH MOSTLY CLOUDY SKIES FROM SUNSET THROUGH AT LEAST MIDNIGHT. FCST SOUNDINGS HINT AT SOME CLEARING AFTER MIDNIGHT...AND WILL SHOW A DECREASE TO PARTLY CLOUDY FROM MIDNIGHT TO SUNRISE. FOR TEMPS...MOS GUIDANCE AGREES PRETTY WELL (ALBEIT A FEW DEGREES HIGHER) WITH THE 1000-850 MB THICKNESSES OFF THE GFS/NAM...AND WILL COMPROMISE BETWEEN MOS GUIDANCE AND THE THICKNESSES AND SHOW A RANGE FROM THE MID 40S IN THE NORTHEAST COASTAL PLAIN TO THE UPPER 40S TO AROUND 50F IN SOUTHERN AND WESTERN PORTIONS OF THE AREA. IF EXTENSIVE MID/UPPER LEVEL CLOUDS ARRIVE BY EARLY AFTERNOON IN THE WEST...THIS MAY BE TOO WARM IN THE WEST BY A DEGREE OR TWO. LOWS TONIGHT SOMEWHAT DIFFICULT WITH PERVASIVE MID/UPPER LEVEL CLOUD COVER EXPECTED THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. LOWS WILL ENTIRELY DEPEND ON WHICH LOCATIONS HAVE THE OPPORTUNITY TO RADIATE WELL FOR SEVERAL HOURS BEFORE SUNRISE. AT THIS TIME...WILL BLEND CLOSE TO WHAT MOS GUIDANCE IS SUGGESTING...WITH A RANGE OF 27-30F ACROSS THE AREA DUE TO THE COOL/DRY AIRMASS IN PLACE ASSOC/W THE SFC HIGH. -VINCENT && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY... SUNDAY: SFC HIGH PRESSURE CONTINUES MOVING FURTHER OFFSHORE DURING THE DAY SUNDAY...ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP ACROSS THE CAROLINAS. THIS WILL CAUSE WARM ADVECTION TO STRENGTHEN OVER THE AREA BY OR SHORTLY AFTER SUNRISE...ALLOWING ENOUGH MOISTURE/LIFT FOR LOW STRATUS TO DEVELOP. WHILE GFS/NAM FCST SOUNDINGS AGREE THAT THE WESTERN PIEDMONT WILL BE COMPLETELY OVERCAST IN LOW STRATUS BY 15-18Z...THEY ARE MORE AMBIGUOUS TOWARD THE TRIANGLE AND NORTHEAST COASTAL PLAIN. WILL SHOW SKIES BECOMING MOSTLY CLOUDY TO OVERCAST IN THE FAR WESTERN PIEDMONT BY EARLY AFTERNOON WHERE AN UPSLOPE COMPONENT IN THE LOW LEVEL FLOW WILL HELP PROVIDE ADDITIONAL LIFT IN VICINITY OF THE FOOTHILLS/MOUNTAINS...WITH INCREASING CLOUD COVER (PARTLY TO MOSTLY CLOUDY) ELSEWHERE THROUGH THE DAY IN ASSOC/W PERSISTENT WARM ADVECTION. A SOMEWHAT DIFFICULT HIGH TEMP FORECAST THAT WILL ULTIMATELY DEPEND ON CLOUD COVER. 1000-850MB THICKNESSES START OUT AROUND 1310-1320M 12Z SUN...INCREASING TO 1340-1350M BY 00Z. WITH FULL SUN...THESE THICKNESSES WOULD YIELD HIGHS IN THE UPPER 50S TO NEAR 60F. WITH OVERCAST LOW CLOUD COVER...HOWEVER... HIGHS WOULD STRUGGLE TO MAKE IT OUT OF THE 40S. WILL TREND TOWARD MOS GUIDANCE...SHOWING A RANGE FROM AROUND 49-50F IN THE TRIAD TO THE UPPER 50S TO AROUND 60F IN THE SE COASTAL PLAIN. WOULD NOT BE SURPRISED TO SEE TEMPS BUST 3-5F...DEPENDING ON THE DEGREE OF CLOUD COVER ACROSS THE AREA. W/REGARD TO PRECIP CHANCES...BOTH THE GFS/NAM SHOW LIGHT QPF IN ASSOC/W WARM ADVECTION IN THE WESTERN PIEDMONT AND FOOTHILLS FROM NOON THROUGH SUNSET. HOWEVER...FCST SOUNDINGS SHOW RATHER SHALLOW MOISTURE WITH SATURATION NOT EVEN EXTENDING UP TO THE 0C ISOTHERM. IT WOULD BE TOUGH TO GET MEASURABLE PRECIP IN THE WESTERN PIEDMONT WITH THOSE TYPE OF THERMAL/MOISTURE PROFILES... AND HAVE DECIDED TO REMOVE MENTION OF A SLIGHT OR LOW CHANCE OF MEASURABLE RAIN AND REPLACE IT WITH A CHANCE OF DRIZZLE IN THE FAR WESTERN PIEDMONT BEGINNING IN THE AFTERNOON. A BETTER CHANCE FOR A FEW HUNDREDTHS OF LIGHT RAIN WILL BE FURTHER WEST IN THE FOOTHILLS / BLUE RIDGE WHERE UPSLOPE FLOW WILL ENHANCE LIFT. SUNDAY NIGHT: SOUTHERLY LOW LEVEL FLOW / WARM ADVECTION CONTINUES ON SUNDAY NIGHT AS THE GRADIENT ACROSS THE CAROLINAS REMAINS PINCHED BETWEEN STRONG HIGH PRESSURE WELL OFFSHORE THE MID-ATLANTIC AND STRONG LOW PRESSURE ACROSS THE UPPER GREAT LAKES. WITH CONTINUED WARM ADVECTION...EXPECT MOSTLY CLOUDY TO OVERCAST SKIES ACROSS THE ENTIRE AREA. CANNOT RULE OUT SOME DRIZZLE ACROSS THE SE COASTAL PLAIN...SANDHILLS...TRIANGLE AND WESTERN PIEDMONT WHERE THE BETTER SATURATION IS EXPECTED. FCST SOUNDINGS STILL SHOW RATHER SHALLOW MOISTURE WITH SATURATION NOT EVEN EXTENDING ABOVE THE 0C ISOTHERM...AND THIS IS THE REASON FOR KEEPING MEASURABLE POPS OUT OF THE FCST. DUE TO EXTENSIVE CLOUD COVER AND CONTINUED WARM ADVECTION...EXPECT MUCH MORE MODERATE LOWS THAN SAT NIGHT...AND WILL TREND CLOSE TO MOS GUIDANCE SHOWING LOWS RANGING FROM 44-50F FROM NW TO SE. MONDAY: WARM ADVECTION CONTINUES ON MONDAY...ALTHOUGH LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY BY THE AFTERNOON HOURS AS A FRONT ASSOC/W LOW PRESSURE NORTH OF THE GREAT LAKES CROSSES INTO THE TN/OH VALLEY AND APPROACHES THE SOUTHERN APPALACHIANS BY 00Z TUE. FCST SOUNDINGS SHOW A RATHER CONSIDERABLE MID-LEVEL CAP FOR ALMOST THE ENTIRE DAY MONDAY...SO ALTHOUGH TEMPS/DEWPOINTS WILL BE UNSEASONABLY WARM BY THE AFTERNOON HOURS...DO NOT EXPECT ANY SUBSTANTIAL (HEAVY) SHOWER ACTIVITY GIVEN THAT THE EQUILIBRIUM LEVEL SHOULD BE ONLY 8-10 KFT AGL. WILL ADD A SLIGHT CHANCE OF SHOWERS FOR THE AFTERNOON HOURS DURING PEAK HEATING. WILL KEEP POPS ONLY AT SLIGHT CHANCE GIVEN NO (OR VERY LITTLE) UPPER LEVEL HELP. HIGH TEMPS LOOK WAY ABOVE NORMAL WITH RATHER STRONG LOW LEVEL SOUTHERLY FLOW...IN FACT...GFS/NAM FCST SOUNDINGS SHOW AROUND 30 KT FLOW AT 925 MB...AND 35-40 KT FLOW AT 850 MB. WILL FCST HIGHS RANGING FROM THE MID 60S WEST TO THE LOWER 70S EAST/SE. IF THERE ARE ENOUGH BREAKS IN CLOUD COVER TO ALLOW MIXING EVEN IN THE LOWEST FEW KFT AGL IT COULD BE RATHER BREEZY MON AFTERNOON. FOR NOW...WILL SHOW 10-15 MPH SOUTHERLY WINDS WITH GUSTS UP TO 25 MPH. MONDAY NIGHT: THE WEAK FRONT IS EXPECTED TO MAKE IT INTO THE FOOTHILLS AND POSSIBLY THE FAR WESTERN PIEDMONT MONDAY NIGHT BEFORE STALLING OUT. NOT MUCH IN THE WAY OF LIFT ON MON NIGHT...VIRTUALLY NOTHING IN THE UPPER LEVELS...AND ONLY VERY WEAK LOW LEVEL CONVERGENCE IN THE LOWER LEVELS IN VICINITY OF THE BOUNDARY. BOTH THE GFS/NAM TRY AND SHOW LIGHT QPF OVER THE ARE MON NIGHT IN ASSOC/W THE BOUNDARY...SO HAVE DECIDED TO LEAVE A SLIGHT CHANCE OF SHOWERS IN THE FCST FOR MONDAY NIGHT. DUE TO CONTINUED SOUTHERLY FLOW AND CLOUD COVER...WILL FCST MILD LOW TEMPS IN THE LOWER/MID 50S...WHICH IS THE AVERAGE HIGH FOR THIS TIME OF YEAR! THESE VALUES ARE CLOSE TO THE MEX MOS GUIDANCE NUMBERS. -VINCENT && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... A COLD FRONT WILL APPROACH AND MOVE ACROSS THE REGION TUESDAY... STALLING SOUTH OF THE AREA TUESDAY NIGHT. WHILE THERE WILL BE A CHANCE FOR RAIN... THE MOIST LAYER IS VERY SHALLOW... SO RAIN TOTALS SHOULD REMAIN RATHER LOW. ANOTHER BOUNDARY APPROACHES THE AREA FROM THE NORTH WEDNESDAY AND LINGERS ALONG THE NORTH CAROLINA/VIRGINIA BORDER THURSDAY... UNTIL A STORM SYSTEM OVER THE CENTRAL U.S. WORKS ITS WAY EAST/NORTHEAST THURSDAY NIGHT INTO FRIDAY MORNING. HIGH PRESSURE RIDGING FROM THE FROM THE SOUTH ATLANTIC WEST ACROSS THE GULF COAST STATES WILL SLOW THE ADVANCEMENT OF THIS FRONT INTO NORTH CAROLINA UNTIL WELL INTO THE DAY FRIDAY. THUS POPS HAVE BEEN ADJUSTED FOR THE FRIDAY TIME PERIOD. HIGHS TUESDAY AND WEDNESDAY WILL BE IN THE 60S... FALLING INTO THE 50S THURSDAY AND FRIDAY. LOWS TUESDAY NIGHT AND WEDNESDAY NIGHT WILL BE IN THE 40S... THEN RANGE FROM THE MID 30S NORTHWEST TO LOWER 40S SOUTHEAST THURSDAY NIGHT. -RHJ && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 1230 AM SATURDAY... AN UPPER LEVEL DISTURBANCE WILL EXIT THE AREA BY 06-09Z THIS MORNING...WHILE HIGH PRESSURE AT THE SURFACE BUILDS IN FROM THE WEST DURING THE DAY. THIS WILL ALLOW FOR VFR CONDITIONS IN CLEAR OR MOSTLY CLEAR SKIES THROUGH THE ENTIRE TAF PERIOD. ALTHOUGH BKN VFR CEILINGS ARE CURRENTLY (AS OF 05Z) LOCATED JUST TO THE WEST OF THE TRIAD IN THE NC FOOTHILLS/ MOUNTAINS...DO NOT EXPECT THIS CLOUD COVER TO AFFECT THE KINT/KGSO TAF SITES. EVEN IF IT DID...IT WOULD BE FOR JUST A FEW HOURS THIS MORNING...AND CEILINGS WOULD BE VFR IN THE 4-5 KFT RANGE. ALTHOUGH WINDS HAVE BECOME LIGHT/VARIABLE OR LIGHT FROM THE NORTHWEST AT KINT/KGSO/KRDU...ENOUGH OF A GRADIENT EXISTS TO ALLOW SOME GUSTINESS AT KFAY/KRWI TAF SITES THROUGH ROUGHLY 07-09Z...AFTER WHICH THOSE TAF SITES SHOULD BECOME LIGHT/VARIABLE OR OUT OF THE NORTHWEST AT ~5 KNOTS. WINDS WILL BECOME LIGHT/VARIABLE EVERYWHERE BY 18-21Z THIS AFTERNOON AS HIGH PRESSURE BECOMES CENTERED OVERHEAD. LOOKING BEYOND THIS EVENING...MVFR OR IFR CIGS WITH STRATUS ARE POSSIBLE BY SUNDAY MORNING AS THE HIGH PRESSURE AREA SHIFTS OFFSHORE AND RETURN FLOW FROM THE SOUTHEAST ENSUES. THESE LOW CLOUDS ARE LIKELY TO DEVELOP BEFORE DAWN AT FAY AND SPREAD OVER THE REST OF CENTRAL NC BY EARLY SUNDAY AFTERNOON. THESE ADVERSE CONDITIONS MAY PERSIST THROUGH TUESDAY...AS A COLD FRONT APPROACHES NC BUT THEN STALLS JUST TO OUR NORTHWEST INTO MIDWEEK. WE WILL ALSO SEE RAIN CHANCES FROM LATE SUNDAY LASTING INTO WEDNESDAY...PARTICULARLY AT INT/GSO...CLOSER TO THE STALLED FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...RHJ AVIATION...VINCENT nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 830 PM CST SAT DEC 13 2008 SHORT TERM...CHALLENGES FOR UPDATE INVOLVE ONGOING HEADLINES AND TEMPERATURES. SO FAR EARLY IN THE EVENT NO BIG SURPRISES. SNOW AREA CONTINUES TO ORGANIZE ACROSS SOUTHERN HALF OF FA IN AREA OF BEST 850MB WARM ADVECTION AND ISENTROPIC LIFT FROM 290K SURFACE. CURRENTLY ENHANCED SNOW BAND ROUGHLY ALONG I94/HIGHWAY 10 CORRIDOR FROM CENTRAL DAKOTAS TO DTL. SURFACE LOW TO ONLY MOVE SLOWLY EAST OVERNIGHT ACROSS NEBRASKA AND WITH NO SIGNIFICANT TIGHTENING OF SURFACE GRADIENT WINDS TO CONTINUE IN THE 20 TO 35 MPH RANGE. AS SNOW GRADUALLY INCREASING IN COVERAGE/INTENSITY VISIBILITIES BEGINNING TO DROP WITH SOME LOCAL LAW ENFORCEMENT ADVISING NO TRAVEL DUE TO ZERO VSBY. OVER FAR SE FA PRETTY QUIET AS YET HOWEVER KABR RADAR INDICATING ENHANCED BAND OF SNOW LIFTING NE AND RUC CONTINUES IN AGREEMENT OF LIFTING ENHANCED BAND OF SNOW THROUGH SE THIRD OF FA THROUGH SUNDAY. AS A RESULT FEEL CURRENT HEADLINES IN GOOD SHAPE AND WILL KEEP TIMING AND BLIZZARD/WINTER STORM COVERAGE GOING FOR NOW. TEMPERATURES BEHIND BAROCLINIC RIBBON DROPPING OFF A LITTLE QUICKER THAN CURRENT TRENDS INDICATE BUT LOOKING UPSTREAM MINIMUMS SHOULD NOT BE TOO FAR OFF. WILL ONLY BE MAKING MINOR TWEAKS TO CURRENT FORECAST. && .AVIATION...WIDESPREAD MVFR/IFR CIGS TO REMAIN ACROSS FA OVERNIGHT AND EXPECT VSBYS TO CONTINUE TO LOWER AS SNOW BECOMES MORE ORGANIZED OVERNIGHT. COMBINED WITH WIND SHOULD BE CONSISTENTLY BLO 1 MILE LATE TONIGHT INTO SUNDAY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR NDZ024-026>030-038- 039-049-052. BLIZZARD WARNING FROM 9 PM THIS EVENING TO 6 AM CST MONDAY FOR NDZ053. BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR NDZ006>008-014>016- 054. MN...BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR MNZ001>003-005-007- 008-013>015-022. BLIZZARD WARNING FROM 9 PM THIS EVENING TO 6 AM CST MONDAY FOR MNZ027-029-030-040. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ006-009-016- 017-023-024-028. BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR MNZ004. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR MNZ031-032. && $$ VOELKER nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 1033 AM CST SAT DEC 13 2008 .DISCUSSION...SYSTEM IS UNFOLDING PRETTY MUCH AS EXPECTED SO FAR. RADAR IMAGERY IS INDICATING -SN ACROSS NORTH CENTRAL/NW ND WITH RETURNS BEGINNING TO FILL IN TO THE SOUTH. AS SYSTEM CONTINUES TO EVOLVE WOULD EXPECT ISENTROPIC LIFT TO STRENGTHEN AND GRADUALLY MOVE INTO THIS FA. CURRENT FORECAST HANDLES THIS WELL. LOW-LEVEL (925MB) COLD AIR ADVECTION IS A BIT STRONGER AS SFC TEMPS ACROSS THE NW FA CONTINUE TO FALL. 12Z RUC/NAM/GFS ALL SHOW 925MB COLD AIR ADVECTION WILL CONTINUE THROUGH THE DAY. ADJUSTED HOURLY TEMPS (STEADY OR FALLING) TO ACCOUNT FOR THIS. MAIN CONCERN WILL BE ONSET OF BLIZZARD CONDITIONS. WITH DECENT LOW-LEVEL COLD AIR ADVECTION WINDS MAY INCREASE A BIT QUICKER THAN ORIGINALLY THOUGHT. MUCH WILL DEPEND UPON FALLING SNOW INTENSITY. STILL A BIT OF DRY AIR TO OVERCOME...AND THINK 00Z START TIME FOR MUCH OF THE BLIZZARD AREA STILL REASONABLE (CONSIDERING EXPECTED SNOW INTENSITY AND WIND SPEEDS). WILL KEEP AN EYE ON WIND SPEEDS AND SNOW INTENSITY...BUT DO NOT FORESEE NEEDING TO BEGIN BLIZZARD ANY EARLIER. && .AVIATION...WINDS WILL TURN NORTH AND NORTHEAST AND INCREASE TO 15 TO 25 MPH TODAY AND TO 20 TO 35 MPH TONIGHT AND SUNDAY. PATCHY LOW CLOUDS AND FOG WILL GIVE WAY TO MOSTLY MVFR CIGS TODAY. THEN INCREASINGLY LOWER VISIBILITIES IN SNOW AND BLOWING SNOW TONIGHT INTO SUNDAY CAUSING IFR CONDITIONS. && .PREV DISCUSSION... /ISSUED 430 AM CST SAT DEC 13 2008/ SHORT TERM... TOUGH FCST THIS MORNING...MODELS REMAIN IN REASONABLE AGREEMENT BUT CONTINUE TO HAVE SLIGHT BUT IMPORTANT DIFFERENCES IN SNOW AREA. GFS IS A BIT FARTHER SOUTH AND EAST WITH SFC LOW MORE OVER NEBRASKA INTO WESTERN IOWA THEN TO NORTH CENTRAL WISCONSIN....NAM A BIT FARTHER NORTH MORE FROM SIOUX FALLS-BROOKINGS TO NORTHWEST WISCONSIN AND THIS IS SIMILAR TO CANADIAN. SOME WRF AND MM5 MODELS ON THE WEB VIA UNIVERSITY OF WISCONSIN AND WFO DETROIT INDICATE SFC LOW FARTHER NORTH FROM WATERTOWN TO INTERNATIONAL FALLS. THIS ALMOST FITS THE RUC BETTER. THE TRACK OF THE LOW WILL HAVE AN IMPACT ON WHERE THE HEAVIEST SNOWS FALL SUNDAY. FOR TODAY...THE ARCTIC AIRMASS WILL OOZE SOUTHWARD AND ALREADY SEEING EVIDENCE OF 5-10 DEGREE TEMP FALL ALONG MB/ND BORDER SINCE 06Z. HOW FAST THIS WILL DROP SOUTH WILL DETERMINE HIGH TEMPS TODAY...BUT FOR MOST AREAS THEY WILL FALL FROM 12Z READINGS EXCEPT FOR FAR SE ND/WCNTRL MN. LIGHT SNOW WILL STREAK EAST ALONG CANADIAN BORDER TODAY AND THIS HAS BEEN IN AGREEMENT IN PAST MODEL RUNS. AREA OF SNOW CAUSED BY 850 MB SOUTHERLY WINDS AND MOISTURE OVERRUNING THE COLD AIRMASS. TONIGHT WILL START TO SEE THE AFFECTS OF THE UPPER WAVE AND SFC LOW TAKE OVER. MODEL DATA SHOWS STRONG 850 MB WARM ADVECTION WITH EAST WINDS AT 850 MB OVER THE AREA OVER A COOLING SFC-925 MB LAYER. STRONG THETA-E ADVECTION AS WELL AT 850 MB AND TIME HEIGHT CROSS SECTIONS AT FARGO AND GRAND FORKS ALL SHOW DEEP VERTICAL MOTION UP TO 300 MB 06Z SUN THRU 00Z MON AS UPPER WAVE MOVES OVER THE AREA. TEMPERATURE PROFILES SHOW -11 TO -14C AIR IN THE 700 MB LAYER AND IN AREA OF MAX VERTICAL MOTION SO SNOW GROWTH WILL BE EFFICIENT. ANOTHER THING IS JUST HOW MUCH QPF WILL THERE BE AS TEMPS DROP BELOW ZERO LATER TONIGHT AND SUNDAY SHOULD BE VERY HIGH SNOW TO WATER RATIOS. ALL IN ALL WOULD APPEAR TO A GOOD SET UP FOR HVY SNOW IN ALL AREAS. MAX QPF VALUES FROM THIS EVENT OVER NRN MN AND BEST THREAT FOR 12+ WOULD BE IN THE BEMIDJI-PARK RAPIDS AREAS WITH A BIT LESS SNOWFALL FARTHER WEST INTO ERN ND. SREF MODEL WOULD INDICATE HIGHEST AMTS NRN ND INTO NRN MN WITH A SHARP CUTOFF INTO NRN SD WHILE GFS WOULD HAVE HVY QPF INTO SD. AS FOR BLIZZARD CONDITIONS...WINDS IN THE 925 MB TO SFC LAYER TO GET PRETTY STRONG UP TO NR 40 KTS ON SUNDAY AND THEY DO TURN NORTHERLY OVER ERN ND AND THE VALLEY. 850 MB WINDS NEVER REALLY LINK UP BUT THE SFC GRADIENT IS PRETTY TIGHT WHICH USUALLY OVERCOMES ANY LACK OF A DEEP ADIABATIC LAYER. THUS WOULD EXPECT 925 MB WINDS OF 35-40 KTS TO MIX DOWN FOR GUSTS WITH SUSTAINED VALUES CLOSER TO 25-30 KTS MOSTLY LATE TONIGHT INTO SUNDAY EVENING. THESE WOULD BE SUFFICIENT TO CREATE BLIZZARD CONDITIONS WITH FALLING SNOW. ANOTHER PLUS IS THAT TEMPERATURES AND WIND CHILLS WILL BE DANGEROUSLY LOW. SO ALL IN ALL LOOKS PRETTY CONFIDENT FOR BLIZZARD CONDITIONS TO DEVELOP OVERNIGHT INTO SUNDAY EVEN IF SOME AREAS MAY NOT SEE HUGE AMOUNTS OF SNOW. LONG TERM... NO CHANGES MADE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR NDZ049-052-053. BLIZZARD WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR NDZ006>008-014>016-024-026>030-038-039-054. MN...BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR MNZ029-030-040. BLIZZARD WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR MNZ001>005-007-008-013>015-022-027. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR MNZ006-009-016-017-023-024-028. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR MNZ031-032. && $$ TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 430 AM CST SAT DEC 13 2008 .SHORT TERM... TOUGH FCST THIS MORNING...MODELS REMAIN IN REASONABLE AGREEMENT BUT CONTINUE TO HAVE SLIGHT BUT IMPORTANT DIFFERENCES IN SNOW AREA. GFS IS A BIT FARTHER SOUTH AND EAST WITH SFC LOW MORE OVER NEBRASKA INTO WESTERN IOWA THEN TO NORTH CENTRAL WISCONSIN....NAM A BIT FARTHER NORTH MORE FROM SIOUX FALLS-BROOKINGS TO NORTHWEST WISCONSIN AND THIS IS SIMILAR TO CANADIAN. SOME WRF AND MM5 MODELS ON THE WEB VIA UNIVERSITY OF WISCONSIN AND WFO DETROIT INDICATE SFC LOW FARTHER NORTH FROM WATERTOWN TO INTERNATIONAL FALLS. THIS ALMOST FITS THE RUC BETTER. THE TRACK OF THE LOW WILL HAVE AN IMPACT ON WHERE THE HEAVIEST SNOWS FALL SUNDAY. FOR TODAY...THE ARCTIC AIRMASS WILL OOZE SOUTHWARD AND ALREADY SEEING EVIDENCE OF 5-10 DEGREE TEMP FALL ALONG MB/ND BORDER SINCE 06Z. HOW FAST THIS WILL DROP SOUTH WILL DETERMINE HIGH TEMPS TODAY...BUT FOR MOST AREAS THEY WILL FALL FROM 12Z READINGS EXCEPT FOR FAR SE ND/WCNTRL MN. LIGHT SNOW WILL STREAK EAST ALONG CANADIAN BORDER TODAY AND THIS HAS BEEN IN AGREEMENT IN PAST MODEL RUNS. AREA OF SNOW CAUSED BY 850 MB SOUTHERLY WINDS AND MOISTURE OVERRUNING THE COLD AIRMASS. TONIGHT WILL START TO SEE THE AFFECTS OF THE UPPER WAVE AND SFC LOW TAKE OVER. MODEL DATA SHOWS STRONG 850 MB WARM ADVECTION WITH EAST WINDS AT 850 MB OVER THE AREA OVER A COOLING SFC-925 MB LAYER. STRONG THETA-E ADVECTION AS WELL AT 850 MB AND TIME HEIGHT CROSS SECTIONS AT FARGO AND GRAND FORKS ALL SHOW DEEP VERTICAL MOTION UP TO 300 MB 06Z SUN THRU 00Z MON AS UPPER WAVE MOVES OVER THE AREA. TEMPERATURE PROFILES SHOW -11 TO -14C AIR IN THE 700 MB LAYER AND IN AREA OF MAX VERTICAL MOTION SO SNOW GROWTH WILL BE EFFICIENT. ANOTHER THING IS JUST HOW MUCH QPF WILL THERE BE AS TEMPS DROP BELOW ZERO LATER TONIGHT AND SUNDAY SHOULD BE VERY HIGH SNOW TO WATER RATIOS. ALL IN ALL WOULD APPEAR TO A GOOD SET UP FOR HVY SNOW IN ALL AREAS. MAX QPF VALUES FROM THIS EVENT OVER NRN MN AND BEST THREAT FOR 12+ WOULD BE IN THE BEMIDJI-PARK RAPIDS AREAS WITH A BIT LESS SNOWFALL FARTHER WEST INTO ERN ND. SREF MODEL WOULD INDICATE HIGHEST AMTS NRN ND INTO NRN MN WITH A SHARP CUTOFF INTO NRN SD WHILE GFS WOULD HAVE HVY QPF INTO SD. AS FOR BLIZZARD CONDITIONS...WINDS IN THE 925 MB TO SFC LAYER TO GET PRETTY STRONG UP TO NR 40 KTS ON SUNDAY AND THEY DO TURN NORTHERLY OVER ERN ND AND THE VALLEY. 850 MB WINDS NEVER REALLY LINK UP BUT THE SFC GRADIENT IS PRETTY TIGHT WHICH USUALLY OVERCOMES ANY LACK OF A DEEP ADIABATIC LAYER. THUS WOULD EXPECT 925 MB WINDS OF 35-40 KTS TO MIX DOWN FOR GUSTS WITH SUSTAINED VALUES CLOSER TO 25-30 KTS MOSTLY LATE TONIGHT INTO SUNDAY EVENING. THESE WOULD BE SUFFICIENT TO CREATE BLIZZARD CONDITIONS WITH FALLING SNOW. ANOTHER PLUS IS THAT TEMPERATURES AND WIND CHILLS WILL BE DANGEROUSLY LOW. SO ALL IN ALL LOOKS PRETTY CONFIDENT FOR BLIZZARD CONDITIONS TO DEVELOP OVERNIGHT INTO SUNDAY EVEN IF SOME AREAS MAY NOT SEE HUGE AMOUNTS OF SNOW. .LONG TERM... NO CHANGES MADE. && .AVIATION... WINDS WILL TURN NORTH AND NORTHEAST AND INCREASE TO 15 TO 25 MPH TODAY AND TO 20 TO 35 MPH TONIGHT AND SUNDAY. PATCHY LOW CLOUDS AND FOG WILL GIVE WAY TO MOSTLY MVFR CIGS TODAY. THEN INCREASINGLY LOWER VISIBILITIES IN SNOW AND BLOWING SNOW TONIGHT INTO SUNDAY CAUSING IFR CONDITIONS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR NDZ049-052-053. BLIZZARD WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR NDZ006>008-014>016-024-026>030-038-039-054. MN...BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR MNZ029-030-040. BLIZZARD WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR MNZ001>005-007-008-013>015-022-027. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR MNZ006-009-016-017-023-024-028. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR MNZ031-032. && $$ RIDDLE nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1251 PM EST SAT DEC 13 2008 .SYNOPSIS... MILDER AIR WILL MOVE IN TODAY AND SUNDAY AS SOUTHERLY FLOW DEVELOPS AHEAD OF A LOW PRESSURE SYSTEM IN THE PLAINS. RAIN WILL BEGIN TO AFFECT PORTIONS OF THE AREA ON SUNDAY...AS THE FRONT MOVES INTO THE OHIO VALLEY. THE FRONT WILL PUSH ACROSS THE AREA ON MONDAY...BRINGING COLDER AIR BACK INTO THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FLO HAS BECOME SRLY THIS MRNG AS SFC LO BEGINS TO GET ITS ACT TOGETHER IN THE SRN PLAINS. WEAK MID LVL DISTURBANCE PASSING TO NORTHWEST OF REGION SPREADING MID LVL CLOUDS INTO FCST AREA. ADDL MID/HI LVL CLOUDS OVER MID MISSISSIPPI VLY POISED TO OVERSPREAD MUCH OF THE FCST AREA THIS AFTN. CURRENT RUC ANALYSIS INDCG CROSS- CONTOUR ISENT LIFT AND LO LVL WAA BECOMES ESTABLISHED BY MID AFTN IN THE MID LVLS (300-305K LEVELS)...AND THAT WILL LIKELY TRANSLATE TO MSTLY CLDY SKIES FOR MUCH OF THE FCST AREA. CANNOT COMPLETELY RULE OUT A FLURRY LATER THIS AFTN ACRS WEST CNTRL OH BUT MODEL SOUNDINGS INDCG SUCH A DRY BNDRY LYR THAT WILL LEAVE OUT ANY MENTION ATTM. WITH CLOUDS FILLING IN THIS AFTN...HAVE LOWERED FCST HIGHS A FEW DEG DESPITE DVLPG WAA. EXPECT AFTN HIGHS WILL RISE MAINLY INTO THE 30S...WITH POTENTIAL AT L40S NEAR AND SOUTH OF THE OHIO RIVER. ZONE AND GRID UPDATES ALREADY SENT. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... GOOD ISENTROPIC LIFT CONTINUES THIS EVENING...AS FA REMAINS BETWEEN RETREATING HIGH AND LOW OVER THE PLAINS. GFS CONTINUES TO TRY AND BRING SOME LIGHT PCPN ACRS THE N/NW TONIGHT. IT IS THE OUTLIER...NOT SUPPORTED BY THE NAM/ECMWF OR THE SREF. KEPT FA DRY TONIGHT. CDFNT...ASSOCIATED WITH SFC LOW...MOVES INTO THE WRN OH VLY BY LATE SUNDAY. BEST ISENTROPIC LIFT AND P DEFS REMAINS ACRS THE WRN HALF OF THE FA. THIS COMBINED WITH RELATIVELY DRY LOW LEVELS...SHOULD KEEP ANY PCPN CHC CONFINED TO THE W ON SUNDAY. PCPN CHCS WILL INCREASE AS SUNDAY NIGHT PROGRESSES AS CDFNT MOVES E UP THE OH VLY. AHEAD OF FNT...H8 JET OF 40-50 KTS WILL AFFECT THE FA SUNDAY INTO SUNDAY NIGHT. SUSTAINED WINDS WILL INCREASE ALONG WITH THE GUSTS. AREA COULD SEE GUSTS TO 40 KTS. FOR NOW...THINK THAT WINDS SHOULD STAY BELOW ADVISORY CRITERIA...BUT WILL MENTION THE WINDS IN THE HWO. FNT PUSHES INTO THE AREA ON MONDAY. TEMPS MAY RAISE FOR A FEW HOURS IN THE MORNING...BUT THEN WILL FALL DURING THE AFTN AS THE COLD AIR WORKS IN. TRENDED TOWARDS THE WARMER MAV LOW TEMPS GUIDANCE FOR TONIGHT...THEN THE ME GUIDANCE ON SUNDAY...SINCE WENT DRIER THAN THE GFS. WITH THE WIND AND RAIN AHEAD OF THE FRONT...WENT WITH THE WARMER MET TEMPS SUNDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS COLD AIR CONTINUES TO SPILL IN THE FA BEHIND THE CDFNT MONDAY NIGHT...PCPN WILL CHANGE TO SNOW OR A RAIN/SNOW MIX. FRONT STALLS IN KY/WV LATE MONDAY NIGHT. BOTH ECMWF AND GFS ARE SHOWING A WAV ON FRONT FOR TUE...WITH THICKNESSES PUSHING BACK TO THE N. THICKNESSES ARE WARM ENUF FOR PCPN TO CHANGE BACK TO RAIN IN THE S AND A SN/RA MIX IN THE N. GFS IS STRONGER WITH SFC LOW THAT PUSHES ACRS THE REGION TUE NGT. WENT CLOSER TO THE WEAKER ECMWF. GFS TRIES TO PUSH ANOTHER WAV N ON WED. STAYED WITH THE ECMWF SOLUTION OF A STRONGER HIGH OVER THE OH VLY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS EXPECTED THRU 18Z SUNDAY. MID/HI LVL CLOUDS CONTINUE TO STREAM ACRS THE TERMINALS THIS AFTN AS ISENT LIFT AND LO LVL WAA BECOMES ESTABLISHED ACRS THE REGION. INITIAL SHOT OF MID LVL CLOUDS WILL SHIFT EAST OF THE TERMINALS THIS EVNG WITH ONLY SCT CLOUDS AS DRIER AIR BRIEFLY ADVECTS INTO OH VLY WITH SFC HI PRES ANCHORED THRU THE CAROLINAS. 50KT 850 LLJ ROTATES AHEAD OF DEEP SFC LO MOVING THRU CNTRL PLAINS AND ACRS REGION LATE TONIGHT. SRLY WINDS LIKELY TO BE LIGHT ENUF FOR SVRL HOURS TO ALLOW FOR LLWS CRITERIA TO BE MET AS BNDRY LYR WINDS VEER TO MORE OF A SW DIR. ALL OF THE TERMINALS SHOULD DROP BELOW LLWS CRIT AFTER DAYBREAK SUNDAY AS SFC WINDS INCREASE ABV 15KTS. DEEPER LO LVL MOISTURE WILL OVERSPREAD THE FCST AREA SUN MRNG WITH CIGS LOWERING INTO AN OVC SC DECK. MODEL SOUNDINGS INDCG SRLY WINDS GUSTING TO 30-35KTS BY LATE SUN MRNG AND CONTINUING THRU THE DAY. COULD SEE A FEW SPRINKLES OR ISOLD -SHRA AT WESTERN TERMINALS LATE IN THE FCST PERIOD...BUT CHANCE REMAINS LOW ENUF TO KEEP OUT OF TERMINALS ATTM. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON MONDAY AND TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...SITES NEAR TERM...RYAN SHORT TERM...SITES LONG TERM...SITES AVIATION...RYAN oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 1127 AM CST SUN DEC 14 2008 .DISCUSSION... && .AVIATION... GUSTY SOUTH WINDS CONTINUING AHEAD OF APPROACHING STRONG COLD FRONT...WITH MVFR CIGS GOING SCATTERED IN NEXT COUPLE OF HOURS. COLD FRONT WILL BE IN THE TULSA AREA AROUND 21Z...THEN SE TO KMLC- KXNA NEAR 00Z AND THROUGH FSM BY 04Z. PERIOD OF MVFR CIGS BEHIND FRONT MOST AREAS...WITH SOME LIGHT -SHRA POSSIBLE OVER NW ARKANSAS ALONG AND IMMEDIATELY BEHIND FRONT. BRIEF PERIOD OF LIGHT FREEZING RAIN OR DRIZZLE MENTIONED AT KXNA/KFYV BUT LITTLE OR NO ACCUM. && .PREV DISCUSSION... /ISSUED 829 AM CST SUN DEC 14 2008/ DISCUSSION... ARCTIC FRONT BARRELING SOUTH AND AT 8 AM WAS THROUGH WICHITA AND EXTENDED BACK INTO NORTHERN TEXAS PANHANDLE. WHILE IT MAY SLOW A LITTLE DURING THE DAY IT DOES APPEAR TO BE A COUPLE OF HOURS AHEAD OF SCHEDULE AND IS EVEN SLIGHTLY FASTER THAN LOCAL WRF AND RUC13. WILL BE ISSUING UPDATES AS NECESSARY THIS MORNING TO REFLECT TIMING. PRECIP AMOUNTS STILL LOOK MINIMAL AND MAINLY CONFINED TO FAR NE OKLAHOMA THROUGH NW ARKANSAS. PREV DISCUSSION... /ISSUED 550 AM CST SUN DEC 14 2008/ DISCUSSION... AVIATION... LOW CLOUDS REMAIN NEAR THE TUL/RVS AREA AND EXTEND SE TO NEAR FSM. CLOUD DECK WILL LIKELY BECOME SCATTERED BY MID MORNING/RISING ABOVE 3KFT. GUSTY SOUTH WINDS WILL CONTINUE AHEAD OF STRONG COLD FRONT...WHICH IS FORECAST TO MOVE INTO THE TUL AREA AROUND 400 PM. BEST RAIN CHANCES WILL LIKELY REMAIN OVER NW ARK THIS EVENING INTO THE OVERNIGHT HOURS ALONG THE FRONT AND IS COVERED WITH A PROB30 GROUP. AVIATION=12 PREV DISCUSSION... WILD SWINGS AND OSCILLATIONS OF THE WEATHER PENDULUM COMING UP. UNSEASONABLY MILD (AT OR NEAR RECORDS) TODAY WITH SOUTH WINDS 20 GUSTING TO ABOUT 40. NOT QUITE AS WINDY AS YESTERDAY. 10Z SURFACE MAP SHOWS ARCTIC FRONT NOW HALF WAY THROUGH KANSAS. NORTHWEST KANSAS IN THE TEENS AND EXTREME SOUTHEAST KANSAS 60. MODELS HAVE BEEN CONSISTENT WITH THIS ARCTIC FRONT PLUS OR MINUS A COUPLE HOURS. LOOKS LIKE VERY CLOSE TO INTERSTATE 44 AXIS @ 5PM. COLD AIR COMING FASTER THAN MODELS SIGNAL. PRECIP ON THE LIGHT SIDE SINCE THE COLD DRY AIR RUSHES IN SO FAST. A WINTRY MIX OF PRECIP CHANGING FROM RAIN TO FREEZING RAIN FREEZING DRIZZLE OR SLEET. CHANCE OF MEASURABLE PRECIP LESS THAN 50 PERCENT AT MOST EASTERN OKLAHOMA ZONES WITH A BETTER THAN EVEN CHANCE FOR NORTHWEST ARKANSAS. LITTLE CHANCE RESIDUAL PRECIP MONDAY EXCEPT EXTREME SOUTHEAST. MONDAY WILL BE AS UNSEASONABLY COLD AS TODAY IS UNSEASONABLY WARM. LOW CONFIDENCE LEVEL FORECAST TUESDAY - THURSDAY AS BOUNDARY BETWEEN ATTIC AIR AND MUCH WARMER AIR JUST SOUTH OSCILLATES NORTH INTO... OR NEAR OUR FORECAST AREA..THEN EVENTUAL BACK SOUTH. MODEL SURFACE TEMPS VARY BY GREATER THAN 25 DEGREES FOR FORECAST TEMPS VALID AT THE SAME TIME. ARCTIC AIR ONCE IN PLACE IS OFTEN DIFFICULT TO DISLODGE SO LEANED HEAVILY COLD. MODELS (GFS ECMWF GLOBAL) DO AGREE THAT ANOTHER SHOT OF VERY COLD WEATHER WILL ARRIVE NEXT WEEKEND. GW && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WIND ADVISORY UNTIL 4 PM SUNDAY FOR OKZ054-OKZ055-OKZ056-OKZ057- OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-OKZ065- OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-OKZ071-OKZ072-OKZ073- OKZ074. AR...WIND ADVISORY UNTIL 4 PM SUNDAY FOR ARZ001-ARZ002-ARZ010-ARZ011. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...14 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 829 AM CST SUN DEC 14 2008 .DISCUSSION... ARCTIC FRONT BARRELING SOUTH AND AT 8 AM WAS THROUGH WICHITA AND EXTENDED BACK INTO NORTHERN TEXAS PANHANDLE. WHILE IT MAY SLOW A LITTLE DURING THE DAY IT DOES APPEAR TO BE A COUPLE OF HOURS AHEAD OF SCHEDULE AND IS EVEN SLIGHTLY FASTER THAN LOCAL WRF AND RUC13. WILL BE ISSUING UPDATES AS NECESSARY THIS MORNING TO REFLECT TIMING. PRECIP AMOUNTS STILL LOOK MINIMAL AND MAINLY CONFINED TO FAR NE OKLAHOMA THROUGH NW ARKANSAS. && .PREV DISCUSSION... /ISSUED 550 AM CST SUN DEC 14 2008/ DISCUSSION... AVIATION... LOW CLOUDS REMAIN NEAR THE TUL/RVS AREA AND EXTEND SE TO NEAR FSM. CLOUD DECK WILL LIKELY BECOME SCATTERED BY MID MORNING/RISING ABOVE 3KFT. GUSTY SOUTH WINDS WILL CONTINUE AHEAD OF STRONG COLD FRONT...WHICH IS FORECAST TO MOVE INTO THE TUL AREA AROUND 400 PM. BEST RAIN CHANCES WILL LIKELY REMAIN OVER NW ARK THIS EVENING INTO THE OVERNIGHT HOURS ALONG THE FRONT AND IS COVERED WITH A PROB30 GROUP. AVIATION=12 PREV DISCUSSION... WILD SWINGS AND OSCILLATIONS OF THE WEATHER PENDULUM COMING UP. UNSEASONABLY MILD (AT OR NEAR RECORDS) TODAY WITH SOUTH WINDS 20 GUSTING TO ABOUT 40. NOT QUITE AS WINDY AS YESTERDAY. 10Z SURFACE MAP SHOWS ARCTIC FRONT NOW HALF WAY THROUGH KANSAS. NORTHWEST KANSAS IN THE TEENS AND EXTREME SOUTHEAST KANSAS 60. MODELS HAVE BEEN CONSISTENT WITH THIS ARCTIC FRONT PLUS OR MINUS A COUPLE HOURS. LOOKS LIKE VERY CLOSE TO INTERSTATE 44 AXIS @ 5PM. COLD AIR COMING FASTER THAN MODELS SIGNAL. PRECIP ON THE LIGHT SIDE SINCE THE COLD DRY AIR RUSHES IN SO FAST. A WINTRY MIX OF PRECIP CHANGING FROM RAIN TO FREEZING RAIN FREEZING DRIZZLE OR SLEET. CHANCE OF MEASURABLE PRECIP LESS THAN 50 PERCENT AT MOST EASTERN OKLAHOMA ZONES WITH A BETTER THAN EVEN CHANCE FOR NORTHWEST ARKANSAS. LITTLE CHANCE RESIDUAL PRECIP MONDAY EXCEPT EXTREME SOUTHEAST. MONDAY WILL BE AS UNSEASONABLY COLD AS TODAY IS UNSEASONABLY WARM. LOW CONFIDENCE LEVEL FORECAST TUESDAY - THURSDAY AS BOUNDARY BETWEEN ATTIC AIR AND MUCH WARMER AIR JUST SOUTH OSCILLATES NORTH INTO... OR NEAR OUR FORECAST AREA..THEN EVENTUAL BACK SOUTH. MODEL SURFACE TEMPS VARY BY GREATER THAN 25 DEGREES FOR FORECAST TEMPS VALID AT THE SAME TIME. ARCTIC AIR ONCE IN PLACE IS OFTEN DIFFICULT TO DISLODGE SO LEANED HEAVILY COLD. MODELS (GFS ECMWF GLOBAL) DO AGREE THAT ANOTHER SHOT OF VERY COLD WEATHER WILL ARRIVE NEXT WEEKEND. GW && .PRELIMINARY POINT TEMPS/POPS... TUL 72 21 28 20 / 10 30 10 20 FSM 73 31 33 29 / 30 70 10 30 MLC 74 25 32 27 / 10 40 10 20 BVO 68 18 25 20 / 10 30 10 20 FYV 67 22 28 25 / 30 60 10 30 BYV 65 22 25 21 / 40 70 10 30 MKO 72 24 28 21 / 20 30 10 20 MIO 68 20 26 19 / 20 50 10 20 F10 73 24 29 21 / 10 30 10 20 HHW 73 33 37 31 / 20 40 20 40 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WIND ADVISORY UNTIL 4 PM SUNDAY FOR OKZ054-OKZ055-OKZ056-OKZ057- OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-OKZ065- OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-OKZ071-OKZ072-OKZ073- OKZ074. AR...WIND ADVISORY UNTIL 4 PM SUNDAY FOR ARZ001-ARZ002-ARZ010-ARZ011. && $$ SHORT TERM...14 LONG TERM....15 ok AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 459 AM CST SUN DEC 14 2008 .DISCUSSION... HAS TAKEN A LITTLE WHILE FOR PRECIP TO PUSH INTO FAR WESTERN CWA THIS MORNING...AS MID LEVEL FRONT REMAINED WEST OF THE AREA UNTIL UPPER LEVEL WAVE BEGAN TO ADVANCE TOWARD THE AREA OUT OF WYOMING. SURFACE OBSERVATIONS IN THE WEST BEGAN REPORTING BLOWING SNOW EVEN IN ADVANCE OF THE FALLING PRECIP THOUGH...EVIDENCE OF THE POWERFUL WINDS BEHIND THE SURFACE LOW...WHICH IS LOCATED BETWEEN KSUX-KCKP IN NORTHWEST IOWA AS OF 10Z. VERY IMPRESSIVE TEMPERATURE GRADIENT ACROSS THE SURFACE BOUNDARY...WITH 10Z OBSERVATIONS SHOWING 20-25F SPREAD BETWEEN I-29 CORRIDOR AND JAMES VALLEY. RUC AND NAM 2 METER TEMPS SEEMED TO HAVE TO BEST HANDLE ON THE SHARP GRADIENT SO FAR...AND HAVE USED THEM AS A GUIDE FOR PUSHING THE COLD AIR THROUGH EASTERN CWA THIS MORNING. BACK TO THE PRECIP...ECHOES HAVE EXPANDED WEST OF THE JAMES RIVER IN THE LAST HOUR OR TWO...AND GENERAL IDEA OF LIFTING HEAVIEST OF PRECIP ACROSS THE WEST AND FAR NORTH PORTIONS OF THE CWA STILL LOOKS VERY REASONABLE GIVEN DEEPER MOISTURE AND FOCUS OF DEEP ISENTROPIC LIFT IN ADVANCE OF THE UPPER WAVE IN THESE AREAS. WEAKLY STABLE PROFILE ABOVE THE MID LEVEL FRONT COULD IN FACT ENHANCE SNOWFALL AMOUNTS...AND HAVE BUMPED TOTALS UP TO A MAX AROUND 8 INCHES OR A LITTLE MORE ALONG AND NORTH OF HIGHWAY 14 IN EAST CENTRAL SOUTH DAKOTA...WITH HIGHER AMOUNTS POSSIBLE FARTHER NORTH OF OUR CWA. LITTLE CHANGE TO GOING WINTER HEADLINES. WILL KEEP BLIZZARD WARNING GOING IN AREA WHERE GREATEST SNOWFALL OF 4 TO 8 INCHES IS EXPECTED...WITH WINTER WEATHER ADVISORY MAINLY FOR BLOWING SNOW THREAT FARTHER SOUTHEAST WHERE SNOW ACCUMULATIONS WILL BE MORE LIMITED. ONLY REAL CHANGE TO THE HEADLINES AT THIS POINT WAS TO EXTEND THE WINTER WEATHER ADVISORY END TIME TO MATCH UP WITH BLIZZARD WARNING EXPIRATION AT 06Z TONIGHT. THOUGH SNOW WILL BE WINDING DOWN THROUGH THE LATE AFTERNOON/EVENING AS THE WAVE LIFTS NORTHEAST...STRONG WINDS WILL CONTINUE TO PRODUCE BLOWING SNOW THREAT INTO THE EVENING. WINDS STRONG ENOUGH...IN FACT...THAT EVEN OUR FAR SOUTHEAST CWA WILL GET IN ON THE HEADLINES THOUGH...WITH A WIND ADVISORY FROM SOUTHEAST OF A KSUX-KSPW LINE INTO THE EARLY EVENING. FOCUS OF CONCERN SHIFTS TO ARCTIC AIR AND DANGEROUS WIND CHILLS VALUES OVERNIGHT AND REALLY THROUGH THE DAY MONDAY BEFORE SURFACE RIDGE MOVES IN AND ALLOWS WINDS TO DROP OFF. GOING LOW TEMPS IN THE 10 TO 15 BELOW RANGE NORTH OF I-90 TONIGHT...COMBINED WITH PERSISTENT NORTHWEST WINDS OF 15 TO 25 MPH WILL LIKELY FORCE WIND CHILLS INTO WARNING RANGE FOR LATE TONIGHT/EARLY MONDAY. HOWEVER...WITH BLIZZARD JUST STARTING TO CRANK UP ACROSS THE AREA...DID NOT WANT TO MUDDLE HEADLINES BY ADDING IN WIND CHILL HEADLINE JUST YET. WILL HIGHLIGHT BITTERLY COLD WIND CHILLS IN THE FORECAST/HWO FOR NOW. STILL LOOKS FAVORABLE FOR MORE ACCUMULATING SNOW ON TUESDAY AS ANOTHER WAVE LIFTS NORTHEAST THROUGH THE VERY COLD AIR IN PLACE. CONTINUED WITH LIKELY POPS ACROSS THE SOUTHERN/SOUTHEASTERN CWA WITH 2-3 INCHES POSSIBLE. && .AVIATION... STRONG STORM SYSTEM WILL BRING WIDESPREAD IFR CIGS AND IFR-LIFR VSBYS EXPECTED IN SN/BLSN TO MUCH OF THE AREA TODAY. BLIZZARD CONDITIONS WITH SFC WNDS 30-40KTS AND VLIFR VSBYS IN SN/BLSN WILL BE MOST PREVALENT NORTHWEST OF KYKN-KFSD-KMWM LINE THROUGH THE DAY...WITH CONDITIONS GRADUALLY IMPROVING FROM SOUTHWEST TO NORTHEAST TONIGHT INTO MONDAY AS LOW PRESSURE LIFTS AWAY FROM THE AREA AND SURFACE GRADIENT BEGINS TO RELAX. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ001- 012-020. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ002- 003-013. WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM CST THIS EVENING FOR IAZ014-021-022-031-032. MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ080- 089-097-098. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ081- 090. BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ071-072. NE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ013. WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM CST THIS EVENING FOR NEZ014. SD...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR SDZ061- 062-065>071. BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR SDZ038>040-050- 052>060-063-064. && $$ JH sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 656 PM MST SAT DEC 13 2008 .DISCUSSION...01Z SURFACE ANALYSIS SHOWED LOW IN NORTH CENTRAL CO. 00Z UPPER AIR ANALYSIS HAD 130KT JET STREAK NOSING INTO CO WITH STRONG LIFT IN LEFT EXIT REGION. STRONG LIFT IMPACTING AREA OF STEEP LAPSE ABOVE ARCTIC AIR WHICH HAS SLIPPED INTO NE. FEW LIGHTNING STRIKES NOTED EARLIER. LATEST RADAR MOSAIC SHOWED CONVECTION SN MOVING THROUGH PORTIONS OF THE CWA. 00Z RUC HAS BAND OF STRONG FRONTOGENESIS FROM EASTERN WY INTO WESTERN SD THROUGH 09Z. SNOW SHOULD CONTINUE TO GENERATE ALONG THIS BOUNDARY AND SHIFT EAST. ANOTHER PUSH OF LIFT WILL BE FURTHER EAST OVER THE CWA LATER TONIGHT. WINDS CONTINUE TO INCREASE OVER THE AREA WITH NUMEROUS REPORTS OF NEAR ZERO VISIBILITY. BITTER COLD/WIND CHILLS CONTINUE UNABATED INTO THE AREA. BLIZZARD WARNING LOOKS GOOD. ADDED CUSTER/FALL RIVER TO THE WINTER STORM WARNING BASED ON SNOWFALL THIS EVENING. && .AVIATION...WIDESPREAD LIFR CONDITIONS OVERNIGHT DUE TO SN/BLSN. && .PREV DISCUSSION... /ISSUED 300 PM MST SAT DEC 13 2008/ DISCUSSION...CURRENT SURFACE ANALYSIS PLACES COLD FRONT STRETCHING FROM LAKE SUPERIOR THROUGH MINNESOTA INTO SOUTHERN SOUTH DAKOTA...WITH LOW OVER SOUTHEAST WYOMING. UPPER LEVEL ANALYSIS PLACES SOUTHWEST FLOW ALOFT OVER OUR AREA AS UPPER TROF WITH AXIS STRETCHING FROM FAR WESTERN MONTANA INTO SOUTHEASTERN IDAHO CONTINUES ITS APPROACH. CURRENT RADAR MOSAIC SHOWING BROAD AREA OF SNOWFALL OVER EASTERN MONTANA STRETCHING INTO NORTHEAST WYOMING AND NUDGING INTO WESTERN SOUTH DAKOTA. TEMPERATURES CONTINUE TO DIVE OVER THE REGION BEHIND THE PROGRESSING FRONT...WITH READINGS AROUND 0 ALREADY NOTED OVER PARTS OF SOUTH CENTRAL/SOUTHEAST MONTANA. SOME FREEZING DRIZZLE AND FOG IS ALSO DEVELOPING AS THE FRONT MARCHES THROUGH...THOUGH SHOULD SWITCH TO SNOW QUICKLY. FOR TONIGHT...AFOREMENTIONED UPPER TROF WILL CONTINUE ITS EASTWARD SLIDE WITH SNOW CONTINUING TO DEVELOP ACROSS THE CWFA. SURFACE LOW WILL SWING INTO NEBRASKA WITH PRESSURE GRADIENT TIGHTENING. WINDS WILL INCREASE GREATLY THIS EVENING BRINGING IN THE VERY COLD AIR. UPSLOPE ENHANCEMENT WILL BRING HIGHER SNOW AMOUNTS TO THE NORTHERN INTO THE CENTRAL BLACK HILLS. THE SECOND AREA OF HIGHER SNOW AMOUNTS IS EXPECTED TO BE TOWARDS SOUTH CENTRAL SOUTH DAKOTA LATER TONIGHT WHERE TIGHT GRADIENT OF 700 MB FRONTOGENESIS IS NOTED. GFS TENDS TO PUT THIS FEATURE FURTHER EAST WITH NAM KEEPING IT OVER OUR AREA. WITH THE NAMS RUN TO RUN CONSISTENCY WITH THIS FEATURE...HAVE PUT MORE VALUE INTO IT. FOR SUNDAY...STORM WILL CONTINUE INTO THE MORNING WHILE UPPER TROF CONTINUES ITS EASTWARD PUSH...WITH AXIS SLIDING INTO WESTERN SOUTH DAKOTA BY THE EVENING. SNOW WILL TAPER OFF SLOWLY FROM WEST TO EAST IN THE AFTERNOON/EVENING WITH WINDS STARTING TO SLOWLY TAPER OFF. WITH THE ARCTIC AIRMASS FIRMLY OVER THE AREA...WIND CHILLS WILL BECOME DANGEROUSLY LOW OVERNIGHT. ON MONDAY...TEMPS WILL REMAIN WELL BELOW AVERAGE THOUGH SOME WARMER AIR WILL WILL TRY TO NUDGE INTO NORTHEAST WYOMING AND THE BLACK HILLS. WITH THE OVERRUNNING FROM THIS...HAVE GONE WITH A CHANCE OF SNOW OVER THE WEST EARLY...PUSHING EAST LATER IN THE EVENING. EXTENDED...THE ARCTIC AIRMASS WILL CONTINUE TO DOMINATE THE WX ON TUESDAY...ALTHOUGH TEMPERATURES WILL MODERATE SLIGHTLY. OVERRUNNING WARM AIR WILL BRING A CHANCE OF SNOW ON TUESDAY. WEDNESDAY THROUGH SATURDAY WILL SEE TEMPS MODERATE MAINLY INTO 20S...SOME TEENS IN FAR NRN SD. WED SHOULD BE DRY WITH A CHC OF SNOW OVER SRN AREAS LATE WED NITE INTO THURS AS A SYSTEM MVS SOUTH OF REGION. NEXT CHC OF PCPN WILL BE FRIDAY NIGHT THRU THE WEEKEND AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES MOVE THRU THE FLOW AND BRING LOW CHANCES OF SNOW. AVIATION...VFR CONDS ARE EXPECTED TO CONTINUE THRU 20Z...THEN CONDITIONS WILL BEGIN TO DETERIORATE WITH IFR CONDS IN SNOW/BLSN/LOW CIGS LIKELY BY 03Z SUNDAY AND CONTINUING THROUGH THE REST OF THE FCST PERIOD. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WARNING UNTIL 9 PM MST SUNDAY FOR CENTRAL BLACK HILLS-NORTHERN BLACK HILLS. BLIZZARD WARNING UNTIL 9 PM MST /10 PM CST/ SUNDAY FOR BENNETT- MELLETTE-TODD-TRIPP. WINTER STORM WARNING UNTIL 6 PM MST SUNDAY FOR FALL RIVER- SOUTHERN BLACK HILLS-SOUTHERN FOOT HILLS. BLIZZARD WARNING UNTIL 9 PM MST SUNDAY FOR BUTTE-CUSTER CO PLAINS-HAAKON-HARDING-HERMOSA FOOT HILLS-JACKSON-NORTHERN FOOT HILLS-NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS- PERKINS-RAPID CITY-SHANNON-SOUTHERN MEADE CO PLAINS- STURGIS/PIEDMONT FOOT HILLS-ZIEBACH. WY...WINTER STORM WARNING UNTIL 9 PM MST SUNDAY FOR WYOMING BLACK HILLS. BLIZZARD WARNING UNTIL 1 PM MST SUNDAY FOR NORTHEASTERN CROOK- NORTHERN CAMPBELL-SOUTHERN CAMPBELL-WESTERN CROOK-WESTON. && $$ HELGESON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 748 PM CST SUN DEC 14 2008 .UPDATE... QUICK UPDATE TO THE FORECAST TO ACCOUNT FOR FRONTAL POSITION. AT 740 PM THE FRONT EXTENDS FROM NEAR CISCO TO MINERAL WELLS TO GAINESVILLE AND IS CLEARLY EVIDENT ON KFWS 88D...MOVING TO THE SOUTH AT AROUND 24 KTS. THIS WILL PUT IT AT DENTON AROUND 815 PM... DOWNTOWN FORT WORTH AROUND 850 PM...DFW AT 905 PM...AND DOWNTOWN DALLAS AROUND 930 PM. ABRUPT WIND SHIFT TO THE NORTH WITH GUSTS TO 45 MPH CAN BE EXPECTED. DURATION OF GUSTY WINDS NOT EXPECTED TO LAST TOO LONG...SO WILL HANDLE WITH AN SPS FOR NOW. TEMPERATURES WILL DROP AS MUCH AS 30-35 DEGREES BEHIND THE FRONT AND ARE ALREADY IN THE UPPER 30S ACROSS FAR NORTHWEST PORTIONS OF THE CWA. CURRENT UPDATE WILL BE TO ADJUST OVERNIGHT LOWS DOWN A FEW DEGREES ACROSS THE NORTH BASED ON UPSTREAM OBS AND ADJUST TIMING OF FRONT IN THE HOURLY GRIDS MORE IN LINE WITH THE LATEST RUC GUIDANCE. SOME LIGHT RETURNS NOTED ACROSS SOUTHERN OKLAHOMA BUT NO OBS SITES REPORTING ANY PRECIP. WILL LIKELY BE MAKING SEVERAL MINOR UPDATES TO ADJUST HOURLY GRIDS THROUGH THE NIGHT BASED ON FRONTAL POSITION. 91/DUNN && .AVIATION... A STRONG COLD FRONT THAT EXTENDED SOUTHEAST OF AN ADA OK /KADA/...FREDERICK OK /KFDR/...LUBBOCK TX /KLBB/ LINE AS OF 23Z...WILL CONTINUE TO MOVE SOUTHEAST AND MAY ACCELERATE AFTER SUNSET. EXPECT THE FRONT TO MOVE INTO THE METROPLEX 02-03Z... AND INTO THE WACO AREA AROUND 06Z. SOUTHERLY WINDS AROUND 20 KNOTS AHEAD OF THE FRONT...WILL GIVE WAY TO NORTHWEST AND NORTH WINDS OF 20 KNOTS WITH FRONTAL PASSAGE. THERE WILL BE A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS OVERNIGHT...MAINLY EAST OF I-35. RAIN CHANCES ARE TOO LOW TO MENTION IN THE TAFS. GUSTY NORTHERLY WINDS OF 20 TO 30 KNOTS ARE EXPECTED THROUGH MONDAY MORNING....WITH SPEEDS EXPECTED TO DECREASE TO 15 TO 20 KNOTS DURING THE AFTERNOON. ANY PRECIPITATION THAT DEVELOPS AFTER 00Z TUESDAY WILL BE LIGHT...BUT TEMPERATURES IN THE METROPLEX WILL BE NEAR FREEZING. HAVE HELD OFF FOR NOW ON MENTIONING ANY -DZ OR -FZDZ IN THE KDFW TAF FOR THE 24-36 HOUR PERIOD. 58 && .PREV DISCUSSION... /ISSUED 343 PM CST SUN DEC 14 2008/ AN ARCTIC COLD FRONT WILL CONTINUE TO SURGE THROUGH THE PANHANDLE AND OKLAHOMA AND WILL MOVE THROUGH ALL OF NORTH TEXAS TONIGHT. THE FRONT HAS SLOWED A BIT THIS AFTERNOON...AS EXPECTED...BUT SHOULD ACCELERATE AFTER SUNSET. THE FRONT SHOULD REACH THE RED RIVER SHORTLY AFTER SUNSET...THE INTERSTATE 20 CORRIDOR BETWEEN 830 PM AND 10 PM...AND MOVE THROUGH ALL OF NORTH TEXAS BEFORE 4 AM. FROPA WILL BE VERY ABRUPT WITH A RAPID DROP IN TEMPERATURES ALONG WITH A QUICK WIND SHIFT FROM SOUTH/SOUTHWEST TO NORTH/NORTHWEST. TEMPERATURES JUST PRIOR TO FROPA WILL BE WARMER THAN THE HIGH TEMPERATURES BOTH MONDAY AND TUESDAY. A FEW SHOWERS OR ISOLATED THUNDERSTORMS MAY DEVELOP THIS EVENING NEAR AND BEHIND THE COLD FRONT...BUT WILL LIMIT POPS TO THE EAST WHERE MOISTURE WILL BE MOST ABUNDANT. SOME POST-FRONTAL SPRINKLES OR LIGHT RAIN WILL BE POSSIBLE MONDAY ACROSS THE SOUTHEAST HALF OF NORTH TEXAS. TEMPERATURES IN THE PRECIP AREA SHOULD BE ABOVE FREEZING SO DO NOT ANTICIPATE ANY FREEZING RAIN/DRIZZLE. HOWEVER...THERE IS A VERY SLIGHT CHANCE THE NORTHWEST ZONES COULD SEE BRIEF LIGHT FREEZING DRIZZLE MONDAY. ISENTROPIC LIFT WILL INCREASE ACROSS THE REGION MONDAY NIGHT AND TUESDAY AS SURFACE LOW PRESSURE DEEPENS ACROSS THE ROCKY MOUNTAIN WEST IN RESPONSE TO A DEVELOPING WEST COAST UPPER TROUGH. THE NORTHWEST ZONES WILL BE AT OR BELOW FREEZING MONDAY NIGHT/TUESDAY MORNING SO LIGHT FREEZING RAIN WILL BE POSSIBLE. TEMPERATURES SHOULD WARM ABOVE FREEZING AREA WIDE TUESDAY AFTERNOON. ALL MODELS SEEM TO AGREE THAT THIS BATCH OF COLD AIR WILL BE QUICKLY REPLACED BEGINNING TUESDAY NIGHT AS SOUTHERLY WINDS RETURN TO THE REGION. BOTH THE ECMWF AND GFS HAVE BACKED OFF ON BRINGING ANOTHER COLD FRONT ACROSS THE RED RIVER WEDNESDAY. EVEN THE 84 HOUR NAM SOLUTION SHOWS THE FRONT LAYING UP NORTH OF THE RIVER. WILL FOLLOW THIS GENERAL SCENARIO BUT WILL STILL UNDERCUT MOS NUMBERS AS THE EXCESSIVE WARMUP THURSDAY AND FRIDAY APPEARS UNREALISTIC. THE EXTENDED GUIDANCE DEPICTS ANOTHER ARCTIC COLD FRONT LATE NEXT WEEKEND. WILL TREND TEMPS DOWN ON DAY 7 BUT WILL HOLD OFF ON INTRODUCING ANY POPS. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 31 35 32 40 40 / 10 20 30 30 20 WACO, TX 36 42 33 44 44 / 10 20 30 30 20 PARIS, TX 29 38 31 36 33 / 20 20 30 40 20 DENTON, TX 28 33 31 39 36 / 10 20 20 30 20 MCKINNEY, TX 30 36 31 38 37 / 20 20 30 40 20 DALLAS, TX 32 37 33 40 40 / 20 20 30 30 20 TERRELL, TX 34 40 33 39 39 / 20 20 30 40 20 CORSICANA, TX 38 42 34 40 40 / 20 20 30 30 20 TEMPLE, TX 36 44 34 47 46 / 10 20 30 30 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 609 PM CST SUN DEC 14 2008 .AVIATION... A STRONG ARCTIC FRONT HAS PUSHED THROUGH BOTH THE KCDS AND KLBB TERMINALS. SUSTAINED NORTHERLY WINDS IN THE 10-20KT RANGE WILL USHER IN MUCH COLDER AIR THROUGH AT LEAST 06Z...INCLUDING THE ONSET OF SUB FREEZING TEMPERATURES DURING THE NEXT 1-3 HOURS. WHILE IT REMAINS LIKELY THAT MVFR CEILINGS WILL EVENTUALLY DEVELOP...SOME UNCERTAINTY REMAINS WRT TIMING FOR LOWER CEILINGS. CURRENT PROGS SUGGEST BKN CEILINGS MAY REMAINAT/ABOVE 4KFT THROUGH THE TAF PERIOD ENDING AT 16/00Z. LOWERING CIGS WILL BE MORE LIKELY THEREAFTER. && .PREV DISCUSSION... /ISSUED 343 PM CST SUN DEC 14 2008/ SHORT TERM... RUC APPEARS TO HAVE BEST HANDLE WITH COLD FRONT MOVING ACROSS THE TEXAS PANHANDLE THIS AFTERNOON. WILL THUS TREND TOWARD ITS SOLUTION. THAT WILL BRING THE FRONT INTO MY NORTHERN ZONES AT AROUND 4 PM TO LUBBOCK BETWEEN 5 AND 6 PM AND THROUGH THE SOUTH PLAINS BY 8 PM. STRONG GUSTY WINDS HAVE BEEN REPORTED BY TEXAS MESONET SITES AHEAD OF COLD FRONT...HOWEVER EXPECT WINDS WILL DIMINISH SLIGHTLY AS FRONT MOVES THROUGH THE REGION AND WILL LET WIND WARNING AND ADVISORY EXPIRE AT 4 PM. CLOUD COVER IS EXPECTED TO INCREASE WITH FRONTAL PASSAGE. ALSO TEMPERATURES TO PLUNGE RAPIDLY THIS EVENING AND THUS CANNOT CANNOT COMPLETELY RULE OUT POSSIBILITY OF SOME LIGHT FREEZING DRIZZLE OR A FEW FLURRIES... WILL HOWEVER CONTINUE TO LEAVE POPS BELOW MENTIONABLE LEVELS. ARCTIC AIR MASS EXPECTED TO BE IN REMAIN IN PLACE ACROSS THE REGION ON MONDAY AND WILL THUS CONTINUE TO UNDERCUT GUIDANCE FOR HIGHS. LONG TERM... MOST DIFFICULT PART OF THE FCST CONTINUES TO BE WHAT TEMPERATURES WILL DO. CONTINUED PREV FCST WHICH KEEPS COOL AIR IN PLACE ACROSS THE NORTHEAST AND AREAS OFF THE CAPROCK...WHILE THE SOUTHWESTERN PORTIONS OF THE AREA HAVE THE POTENTIAL TO CLIMB INTO THE 50S STARTING TUESDAY. SHOULD FINALLY SEE THE AIRMASS MODIFY BY THURSDAY THANKS TO CONTINUED SWLY FLOW FINALLY HELPING TO MIX OUT THE COLD AIR...AND TEMPS AREA WIDE SHOULD FINALLY GET BACK INTO THE MID TO UPPER 50S BY FRI. MODELS CONTINUE TO SHOW ANOTHER DUMP OF COLD ARCTIC AIR MOVING INTO THE AREA BY FRIDAY ALTHOUGH THE TIMINGS HAVE SWITCHED. THE GFS IS NOW THE FASTER THAN THE ECMWF. REGARDLESS...TEMPERATURES WILL ONCE AGAIN GO WELL BELOW NORMAL FOR THE END OF THE WEEK INTO THE WEEKEND. CONTINUES TO APPEAR THAT THIS WILL BE ANOTHER DRY FRONTAL PASSAGE WITH THE POSSIBILITY OF WINDY AND DUSTY CONDITIONS AHEAD OF THE FRONT. JORDAN && && .PRELIMINARY POINT TEMPS/POPS... FRIONA 17 29 19 51 23 / 10 10 10 0 0 TULIA 16 28 17 40 24 / 10 10 0 0 0 PLAINVIEW 18 29 18 44 25 / 10 10 0 0 0 LEVELLAND 22 32 21 53 29 / 10 10 10 0 0 LUBBOCK 22 30 20 49 28 / 10 10 0 0 0 DENVER CITY 25 35 23 55 37 / 10 10 10 0 0 BROWNFIELD 25 32 22 53 33 / 10 10 0 0 0 CHILDRESS 19 25 17 35 24 / 10 10 0 0 0 SPUR 24 29 18 42 29 / 10 10 0 0 0 ASPERMONT 24 28 17 42 31 / 10 10 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 20/99/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 343 PM CST SUN DEC 14 2008 .SHORT TERM... RUC APPEARS TO HAVE BEST HANDLE WITH COLD FRONT MOVING ACROSS THE TEXAS PANHANDLE THIS AFTERNOON. WILL THUS TREND TOWARD ITS SOLUTION. THAT WILL BRING THE FRONT INTO MY NORTHERN ZONES AT AROUND 4 PM TO LUBBOCK BETWEEN 5 AND 6 PM AND THROUGH THE SOUTH PLAINS BY 8 PM. STRONG GUSTY WINDS HAVE BEEN REPORTED BY TEXAS MESONET SITES AHEAD OF COLD FRONT...HOWEVER EXPECT WINDS WILL DIMINISH SLIGHTLY AS FRONT MOVES THROUGH THE REGION AND WILL LET WIND WARNING AND ADVISORY EXPIRE AT 4 PM. CLOUD COVER IS EXPECTED TO INCREASE WITH FRONTAL PASSAGE. ALSO TEMPERATURES TO PLUNGE RAPIDLY THIS EVENING AND THUS CANNOT CANNOT COMPLETELY RULE OUT POSSIBILITY OF SOME LIGHT FREEZING DRIZZLE OR A FEW FLURRIES... WILL HOWEVER CONTINUE TO LEAVE POPS BELOW MENTIONABLE LEVELS. ARCTIC AIR MASS EXPECTED TO BE IN REMAIN IN PLACE ACROSS THE REGION ON MONDAY AND WILL THUS CONTINUE TO UNDERCUT GUIDANCE FOR HIGHS. && .LONG TERM... MOST DIFFICULT PART OF THE FCST CONTINUES TO BE WHAT TEMPERATURES WILL DO. CONTINUED PREV FCST WHICH KEEPS COOL AIR IN PLACE ACROSS THE NORTHEAST AND AREAS OFF THE CAPROCK...WHILE THE SOUTHWESTERN PORTIONS OF THE AREA HAVE THE POTENTIAL TO CLIMB INTO THE 50S STARTING TUESDAY. SHOULD FINALLY SEE THE AIRMASS MODIFY BY THURSDAY THANKS TO CONTINUED SWLY FLOW FINALLY HELPING TO MIX OUT THE COLD AIR...AND TEMPS AREA WIDE SHOULD FINALLY GET BACK INTO THE MID TO UPPER 50S BY FRI. MODELS CONTINUE TO SHOW ANOTHER DUMP OF COLD ARCTIC AIR MOVING INTO THE AREA BY FRIDAY ALTHOUGH THE TIMINGS HAVE SWITCHED. THE GFS IS NOW THE FASTER THAN THE ECMWF. REGARDLESS...TEMPERATURES WILL ONCE AGAIN GO WELL BELOW NORMAL FOR THE END OF THE WEEK INTO THE WEEKEND. CONTINUES TO APPEAR THAT THIS WILL BE ANOTHER DRY FRONTAL PASSAGE WITH THE POSSIBILITY OF WINDY AND DUSTY CONDITIONS AHEAD OF THE FRONT. JORDAN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 17 29 19 51 23 / 10 10 10 0 0 TULIA 16 28 17 40 24 / 10 10 0 0 0 PLAINVIEW 18 29 18 44 25 / 10 10 0 0 0 LEVELLAND 22 32 21 53 29 / 10 10 10 0 0 LUBBOCK 22 30 20 49 28 / 10 10 0 0 0 DENVER CITY 25 35 23 55 37 / 10 10 10 0 0 BROWNFIELD 25 32 22 53 33 / 10 10 0 0 0 CHILDRESS 19 25 17 35 24 / 10 10 0 0 0 SPUR 24 29 18 42 29 / 10 10 0 0 0 ASPERMONT 24 28 17 42 31 / 10 10 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ027-033>035-039-040. WIND ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ021>024-028>030-036-041-042. && $$ 08/14 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 232 AM PST SAT DEC 13 2008 .SYNOPSIS... THE ARRIVAL OF A STRONG ARCTIC COLD FRONT TODAY WILL BRING SNOW...BITING NORTH WINDS...AND FALLING TEMPERATURES TO THE INLAND NORTHWEST. THE COMBINATION OF BLOWING SNOW AND DANGEROUSLY COLD WIND CHILLS WILL CONTINUE INTO SUNDAY. ARCTIC HIGH PRESSURE WILL REMAIN OVER THE PACIFIC NORTHWEST THROUGH MUCH OF THE WEEK WITH SOME OF THE COLDEST TEMPERATURES WE HAVE SEEN IN YEARS. && .DISCUSSION... TODAY...THE INLAND NORTHWEST WILL FEEL THE IMPACT OF THE VERTICALLY STACKED AREA OF LOW PRESSURE SLOWLY TRACKING ACROSS THE REGION. CURRENTLY...THE CENTER OF THE LOW PRESSURE HAS SLIPPED EAST OF THE CASCADES AND IS NEAR WENATCHEE...WHERE WINDS AND PRECIPITATION ARE LIGHT. THE LOW IS SLOWLY FILLING AND WILL TAKE A SSE PATH...SIMILAR TO WHAT IS DEPICTED BY THE 6Z RUC AND NAM. EACH MODEL IS PLAYING CATCH UP WITH THE TRACK OF THIS SYSTEM. THE MORE SOUTHERLY TRAJECTORY IS DUE TO THE PUSH OF THE ARCTIC FRONT WHICH WILL BE SLIPPING SOUTH AND OOZING SOME FRIGID AIR INTO THE NORTHERN VALLEYS TODAY. CURRENTLY SURFACE TEMPERATURES ARE QUITE MILD...IN THE UPPER 20S TO MID 30S...AS THE FORECAST AREA WAS WITHIN THE WARM SECTOR FOR MUCH OF THE NIGHT. THESE READINGS WILL MOST LIKELY BE THE LOWS FOR THE NIGHT...AND THE HIGHS FOR SATURDAY. ONCE THE ARCTIC AIR INVADES THE REGION...ANTICIPATE FALLING TEMPERATURES THROUGH THE DAY UNDER STIFF NORTH-NORTHEAST WINDS WITH SPEEDS OF 20-30 KTS. RECENT RADAR LOOPS SHOW SNOW RETURNS REDEVELOPING AROUND THE CIRCULATION OVER EASTERN WASHINGTON AND ANTICIPATE MORE INTENSIFICATION OF THE SNOW ACTIVITY ACROSS THE NORTHERN ZONES EARLY SATURDAY MORNING. SNOW TO WATER RATIOS WILL JUMP FROM AROUND 12 TO 1 TO ALMOST 20 TO 1...MAKING THE SNOW DRY AND FLUFFY. THIS COUPLED WITH THE INCREASED WINDS WILL LEAD TO BLOWING AND DRIFTING SNOW IN MOST EXPOSED LOCATIONS. TONIGHT AND SUNDAY...THE ARCTIC BOUNDARY SLIPS INTO THE SOUTHEAST ZONES BY THIS EVENING...KEEPING NORTH TO EAST WINDS ACROSS THE REGION. AREAS OF BLOWING AND DRIFTING SNOW WILL CONTINUE AS TEMPERATURES CONTINUE TO PLUMMET. 850MB TEMPS FALL TO -20C UNDER STRONG COLD AIR ADVECTION. THE FRIGID TEMPERATURES AND THE PERSISTENT WINDS WILL LEAD TO DANGEROUS COLD WIND CHILLS OF -10 TO -20 DEGREES INTO THE NIGHT. MEANWHILE...A SHORTWAVE RIDGE ALOFT BUILDS OVER THE REGION WITH MORE STABLE AND DRY CONDITIONS PENETRATING THE NORTHERN TIER ZONES. THE UPPER LEVEL RIDGE HOLD FIRM INTO SUNDAY DESPITE THE FORCE OF ANOTHER PACIFIC LOW ROLLING DOWN THE WA COAST. THIS WILL LEAD TO INCREASED SOUTHERLY FLOW ALOFT...YET THE STABLE LOW LEVEL COLD AIR WEDGE WILL REMAIN UN- BUDGED ACROSS THE REGION. THIS WILL KEEP LOW LEVEL CLOUDS AND LIGHT SNOW SHOWERS OR FLURRIES IN MOST AREAS THROUGH SUNDAY. ANTICIPATE SOME RATHER LOW MAX TEMPERATURES ON SUNDAY WITH LITTLE RECOVERY ANTICIPATED. CURRENT WINTER WEATHER HIGHLIGHTS WILL CONTINUE THROUGH LATE SATURDAY TO EARLY SUNDAY. /RFOX. SUNDAY NIGHT THROUGH WEDNESDAY...SUNDAY NIGHT AN AREA OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL SLIDE SOUTH ALONG THE WASHINGTON AND OREGON COAST KEEPING SOME SNOW SHOWERS ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA. THE BEST CHANCE FOR PRECIPITATION WILL BE OVER THE BLUE MTS WHICH WILL BENEFIT FROM THE MOISTURE WRAPPING AROUND THE LOW AND THE EASTERLY UPSLOPE FLOW. MODEL QPF IS LIGHT BUT A GENEROUS SNOW TO LIQUID RATIO OF 20 TO 1 WILL RESULT IN A COUPLE OF INCHES OF ADDITIONAL SNOWFALL SUNDAY NIGHT IN BLUE MTS BUT BELOW ADVISORY CRITERIA. THE BIG STORY IS THE VERY COLD TEMPERATURES EXPECTED THROUGH MIDWEEK AS ARCTIC AIR SETTLES IN OVER THE INLAND NORTHWEST. AS THE LOW DROPS SOUTH...A SURFACE HIGH WILL BUILD OVER BRITISH COLUMBIA. NORTHEAST FLOW AROUND THE HIGH WILL DRAG VERY COLD AIR INTO THE FORECAST AREA. TEMPERATURES WILL DIP WELL BELOW ZERO ACROSS THE NORTHEAST VALLEYS SUNDAY NIGHT AND REMAIN IN THE DEEP FREEZE THROUGH MIDWEEK WITH DAYTIME TEMPERATURES STRUGGLING TO BREAK INTO POSITIVE TERRITORY. THESE COLD TEMPERATURES WILL COMBINE WITH 15 TO 25 MPH WINDS TO CREATE DANGEROUS WIND CHILL TEMPERATURES FOR THE START OF THE WORKWEEK. 850MB TEMPERATURES START TO MODERATE A BIT BY WEDNESDAY BUT CLEARING SKIES AND LIGHT WINDS ALLOW BITTER COLD TEMPERATURES TO PERSIST. WEDNESDAY NIGHT THROUGH FRIDAY...THE COLD AIR WILL REMAIN IN PLACE AS AN UPPER LEVEL TROUGH APPROACHES THE REGION WEDNESDAY NIGHT. THIS COULD BRING ANOTHER ROUND OF SIGNIFICANT SNOWFALL AS SNOW TO LIQUID RATIOS WILL REMAIN HIGH. /KELCH && .AVIATION... PRECIPITATION HAS SHIFTED NORTH AND EAST OF THE TAF SITES ATTM. MAIN AREA OF SNOW REMAINS ACROSS EXTREME NORTHEAST WASHINGTON AND NORTH IDAHO. AREAS OF FREEZING FOG WILL LINGER NEAR KMWH UNTIL THE AREA OF LOW PRESSURE NEARS THE AREA TOWARD 12Z. AREAS OF SNOW WILL INCREASE ACROSS KEAT AND KOMK...SPREADING TO KMWH BY 12Z SAT. MEANWHILE THE ARCTIC FRONT FROM THE NORTH WILL SPREAD MODERATE TO HEAVY SNOW IN FROM THE NORTH BETWEEN 12Z-18Z SAT INTO KGEG-KCOE- KPUW...AND FINALLY REACHING KLWS AFTER 18Z. ANTICIPATE LIFR CONDITION WITH SNOW AND BLSN WITH NE WINDS 15G25KTS. CIGS WILL IMPROVE ACROSS THE NORTH IN THE LATE AFTERNOON AND EARLY EVENING...AS SKIES CLEAR AND BLSN DECREASES AFTER 0Z SUN. /RFOX. && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 29 1 6 -8 2 -13 / 100 50 30 20 10 10 COEUR D`ALENE 30 1 8 -9 2 -11 / 100 50 30 20 10 10 PULLMAN 33 10 13 -1 7 -3 / 100 70 50 30 20 10 LEWISTON 36 15 20 6 15 3 / 80 90 50 30 20 10 COLVILLE 26 0 10 -9 3 -10 / 90 20 20 10 10 10 SANDPOINT 23 -3 6 -11 0 -12 / 80 40 20 10 10 10 KELLOGG 25 -1 5 -9 0 -10 / 100 70 40 20 20 10 MOSES LAKE 28 8 12 -3 9 -6 / 90 50 40 20 10 10 WENATCHEE 26 8 14 -3 10 -3 / 80 50 40 20 10 10 OMAK 23 8 12 -6 7 -9 / 100 30 30 20 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR NORTHERN PANHANDLE. WINTER STORM WARNING UNTIL 10 AM PST SUNDAY FOR IDAHO PALOUSE. WINTER STORM WARNING UNTIL 4 AM PST SUNDAY FOR COEUR D`ALENE AREA. WINTER WEATHER ADVISORY UNTIL 10 AM PST SUNDAY FOR LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA. WINTER STORM WARNING UNTIL 4 AM PST SUNDAY FOR CENTRAL PANHANDLE MOUNTAINS. WA...WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR NORTHEAST MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY. WINTER STORM WARNING UNTIL 10 AM PST SUNDAY FOR NORTHEAST BLUE MOUNTAINS. WINTER STORM WARNING UNTIL 10 AM PST SUNDAY FOR LOWER GARFIELD AND ASOTIN COUNTIES...WASHINGTON PALOUSE. WINTER STORM WARNING UNTIL 4 AM PST SUNDAY FOR SPOKANE AREA... UPPER COLUMBIA BASIN. WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR MOSES LAKE AREA. WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR WENATCHEE AREA. WINTER STORM WARNING UNTIL 4 AM PST SUNDAY FOR EAST SLOPES NORTHERN CASCADES. WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR WATERVILLE PLATEAU. && $$ wa AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE CHARLESTON SC 402 AM EST MON DEC 15 2008 ...DENSE SEA FOG LIKELY TONIGHT THROUGH AT LEAST TUESDAY NIGHT... .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY INTO TUESDAY...STALLING OUT NORTH OF THE AREA TUESDAY NIGHT. THE FRONT WILL LIFT OFF TO THE NORTH WHILE HIGH PRESSURE RETURNS WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT WILL APPROACH OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SURFACE OBSERVATIONS SUGGEST THE COASTAL TROUGH HAS DISSIPATED WITH ONLY A SUBTLE INVERTED KINK NOTED IN THE ISOBARS JUST INLAND FROM THE COAST. HOWEVER ONGOING WEAK ISENTROPIC LIFT/WARM AIR ADVECTION CONTINUES TO PRODUCE AN EXTENSIVE MID-LEVEL CLOUD DECK ACROSS MUCH OF THE REGION WITH CEILINGS GENERALLY AROUND 7000 FT. THE KCLX RADAR IS EVEN PICKING UP ON SOME ISOLATED SHOWER ACTIVITY ACROSS THE ATLANTIC CENTERED ABOUT 30 NM SOUTHEAST OF HUNTING ISLAND. ONE OR TWO OF THESE SHOWERS COULD MOVE ONSHORE BETWEEN OSSABAW SOUND AND SULLIVANS ISLAND OVER THE NEXT FEW HOURS BUT MOST AREAS WILL REMAIN DRY THROUGH SUNRISE. THE WEAK INSITU WEDGE THAT IS PLACE ACROSS THE MIDLANDS WILL STEADILY DECAY THIS MORNING AS PARENT HIGH PRESSURE SHIFTS SHIFTS EVEN FARTHER OUT IN THE OPEN ATLANTIC. MODELS SUGGEST SOME WEAK ISENTROPIC LIFT ALONG THE 290-300K SURFACES WILL PERSIST THROUGH MUCH OF THE DAY...HOWEVER EXTENSIVE DRY AIR ABOVE 700MB SHOULD KEEP ANY ASSOCIATED SHOWER ACTIVITY FAIRLY ISOLATED. WILL KEEP SLIGHT CHANCE POPS IN PLACE FOR THE ENTIRE FORECAST AREA BUT CONFIDENCE ON ANY ONE LOCATION RECEIVING MEASURABLE RAINFALL IS LOW GIVEN THE LESS THAN FAVORABLE MOISTURE PARAMETERS THAT ARE IN PLACE. TEMPERATURES SHOULD BE A SOLID 10 DEGREES WARMER THAN SUNDAY DESPITE EXTENSIVE CLOUD COVER. EXPECT HIGHS TO REACH THE LOWER 70S EXCEPT NEAR THE COAST WHERE ONSHORE TRAJECTORIES ACROSS LOWER TO MID 50 WATER TEMPERATURES WILL KEEP THE BEACHES CONSIDERABLY COOLER. SHOULD SEE PATCHES OF DENSE SEA FOG DEVELOP ACROSS THE WATERS THIS AFTERNOON AS DEWPOINTS OVER THE ATLANTIC RISE INTO THE MID 60S. SOME OF THIS FOG COULD IMPACT THE BEACHES LATE IN THE AFTERNOON IN THE CONTINUED ONSHORE FLOW. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM TUESDAY/... THE MAIN CONCERN FOR TONIGHT IS THE POTENTIAL FOR DENSE SEA FOG TO MOVE INLAND FROM OFF THE ATLANTIC. DEWPOINTS ARE FORECAST TO RISE INTO THE MID 60S BY LATE AFTERNOON AND PERSIST THROUGH THE NIGHT. SATELLITE DERIVED AND OBSERVED SEA SURFACE DATA INDICATE WATER TEMPERATURES ARE IN THE LOWER TO MID 50S FROM THE SURF ZONE OUT TO AT LEAST 20 NM AND AS HIGHER DEWPOINTS BEGIN TO OVERSPREAD THESE COOL NEARSHORE WATERS EXPECT AREAS OF DENSE FOG TO MATERIALIZE. ANY FOG BANKS THAT FORM SHOULD ADVECT SLOWLY INLAND THIS EVENING UNDER LIGHT SOUTHEAST BOUNDARY LAYER FLOW. ITS A TOUCH CALL ON EXACTLY HOW FAR INLAND THE FOG WILL MIGRATE BUT 03Z SREF VISIBILITY GUIDANCE AS WELL AS THE NAM AND GFS MOS PACKAGES ALL SUGGEST THE FOG WILL PENETRATE INTO AT LEAST THE EASTERN MIDLANDS AND CSRA. WILL KEEP AREAS OF FOG IN THE FORECAST INLAND BUT INTRODUCE DENSE FOG WORDING FOR THE COASTAL ZONES WHERE CONFIDENCE IS HIGHER THAT VISIBILITIES TO DROP TO 1/4 MILE OR LESS. THE DAY SHIFT MAY NEED TO EXPAND THE DENSE FOG WORDING MUCH FARTHER INLAND PENDING 12Z AND 18Z MODEL TRENDS. A DENSE FOG ADVISORY MAY VERY WELL BE NEEDED FOR PORTIONS OF THE FORECAST AREA TONIGHT AND THIS WILL BE RELAYED IN THE MORNING HAZARDOUS WEATHER OUTLOOK. ANY LINGERING ISENTROPIC LIFT WILL BE CONFINED TO EASTERN HALF OF THE FORECAST AREA THIS EVENING BEFORE SHIFTING FARTHER NORTH INTO THE CHARLESTON TRI-COUNTY AREA AFTER MIDNIGHT. WILL KEEP A SLIGHT CHANCE FOR SHOWERS IN THESE AREAS. LOWS WILL RANGE FROM THE LOWER 50S INLAND TO THE UPPER 50S/NEAR 60 AT THE BEACHES. && .LONG TERM /TUESDAY THROUGH SUNDAY/... LATEST MODEL SOLUTIONS CONTINUE TO INDICATE THE COLD FRONT BECOMING STALLED TO THE NORTH AND WEST OF THE FORECAST AREA ON TUESDAY...AS HIGH PRESSURE ALOFT RIDGES NORTHWARD. LACKING ANY STRONG FORCING MECHANISMS...RAIN LOOKS LESS LIKELY ON TUESDAY. HAVE LIMITED RAIN CHANCES TO ONLY A SLIGHT CHANCE OVER THE MARINE ZONES AND NORTHERN SOUTH CAROLINA COUNTIES...CLOSEST TO THE SAGGING FRONT AND A WEAK TROUGH OVER THE WATERS. CONDITIONS CONTINUE TO APPEAR FAVORABLE FOR FOG DEVELOPMENT TUESDAY INTO WEDNESDAY...DUE TO THE COMBINATION OF WEAK SURFACE FLOW AND DECENT LOW LEVEL MOISTURE. SREF VISIBILITIES CONFIRM A DIURNAL PATTERN OF FOG DEVELOPMENT OVER LAND AND SEA AT NIGHT...THEN LINGERING IN THE NEARSHORE WATERS DURING THE DAYTIME HOURS. HAVE MAINTAINED FOG WORDING IN THE FORECAST AND WILL CONTINUE MENTION OF DENSE FOG POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. THE LINGERING FRONT TO THE NORTH WILL LIFT FURTHER AWAY FROM THE AREA ON WEDNESDAY...WHILE SURFACE HIGH PRESSURE BUILDS OVER THE ATLANTIC AND SOUTHEAST STATES. THE REGION WILL THUS REMAIN WITHIN SOUTHERLY FLOW THROUGH FRIDAY...KEEPING TEMPERATURES WELL ABOVE NORMAL THROUGH THE WEEK. EXPECT HIGH TEMPERATURES TO REACH THE MID TO UPPER 70S BY THURSDAY AND FRIDAY. RIDGING AT THE SURFACE AND ALOFT WILL DIMINISH OVER THE WEEKEND...ALLOWING ANOTHER COLD FRONT TO APPROACH THE REGION FROM THE NORTHWEST. GFS SUGGESTS THAT THE REMNANT RIDGING COULD BE SUFFICIENT TO STALL THE FRONT TO THE NORTH AGAIN. HOWEVER BOTH ECMWF AND GFS MODEL RUNS INDICATE A STRONGER SECOND FRONT PUSHING INTO THE FORECAST AREA LATE IN THE WEEKEND/EARLY NEXT WEEK THAT COULD BRING A BETTER CHANCE OF RAIN AND COOLER TEMPERATURES. HAVE THUS INCLUDED SLIGHT CHANCE POPS WITH A COOLING TREND SATURDAY AND SUNDAY. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE NEXT 24 HOURS AT BOTH KCHS AND KSAV. THE LATEST RUC SUGGESTS THERE MAY BE SOME BRIEF CLEARING THAT OCCURS AROUND THE KSAV TERMINAL JUST PRIOR TO SUNRISE. SATELLITE DOES SHOW SOME BREAKS DEVELOPING IN THE CLOUD CANOPY ACROSS EASTERN FLORIDA AND THE ADJACENT ATLANTIC...SO THE RUC MAY VERY WELL BE ON TO SOMETHING. FOG COULD BECOME AN ISSUE UNDER THE CURRENT LIGHT WIND REGIME SHOULD THIS CLEARING MATERIALIZE. WILL INTRODUCE A TEMPO GROUND FOR 4SM BR BETWEEN 10-13Z AT KSAV TO HELP COVER THIS POSSIBILITY. ANY CLEARING THAT DOES OCCUR WILL BE SHORT LIVED WITH WEAK ISENTROPIC LIFT HELPING TO FILL THE CLOUD DECKS BACK IN LATER THIS MORNING. STRATUS AND FOG WILL LIKELY IMPACT BOTH TERMINALS AFTER 03Z TONIGHT AS AREAS OF SEA FOG MOVE INLAND. WILL ONLY SHOW A SLIGHT DETERIORATION AT KSAV WHERE MODELS HIT LOWEST CONDITIONS THROUGH 06Z BUT LIFR AND IFR CONDITIONS WILL LIKELY BE INTRODUCED TO BOTH TAF SITES WITH THE 12Z TAF CYCLE. EXTENDED AVIATION OUTLOOK...IFR OR LIFR CIGS/VSBYS ARE LIKELY MONDAY NIGHT THROUGH EARLY THURSDAY...ESPECIALLY IF SEA FOG AND/OR RADIATION FOG DEVELOPS. && .MARINE... WINDS HAVE FINALLY BECOME SOUTHEAST ACROSS THE ENTIRE MARINE AREA NOW THAT THE COASTAL TROUGH HAS MOVED INLAND AND DISSIPATED. SOUTHEAST WINDS WILL CONTINUE THROUGH THIS EVENING BEFORE SLOWLY VEERING MORE SOUTHERLY AFTER MIDNIGHT. REGIONAL BUOYS INDICATE EASTERLY SWELLS WITH PERIODS OF 8-9 SECONDS ARE KEEPING SEAS FAIRLY ENHANCED WITH COMBINED SEAS OF 4-6 FT ACROSS THE NEARSHORE WATERS AND 5-7 FT ACROSS THE GEORGIA OFFSHORE LEG. WW4 KEEPS THESE SWELLS IN PLACE THROUGH TONIGHT THUS SMALL CRAFT ADVISORIES WILL BE MAINTAINED FOR ALL BUT THE CHARLESTON HARBOR. THE MAIN CONCERN FOR LATE THIS AFTERNOON INTO TONIGHT IS POTENTIAL DEVELOPMENT OF DENSE SEA FOG. LOWER TO MID 60 DEWPOINTS ADVECTING OVER WATER TEMPERATURES IN THE LOWER TO MID 50S SUGGEST THE POTENTIAL FOR DENSE SEA FOG DEVELOPMENT IS RATHER HIGH. COULD SEE AT LEAST PATCHY FOG DEVELOP ACROSS THE WATERS AS EARLY AS THIS AFTERNOON BEFORE BECOME MORE WIDESPREAD THIS EVENING AND OVERNIGHT AS THE FOG BANK SPREADS INLAND. WILL INTRODUCE MENTION OF AREAS OF DENSE FOG WITH VISIBILITIES 1/4NM OR LESS. A MARINE DENSE FOG ADVISORY WILL LIKELY BE NEEDED FOR THE NEARSHORE WATERS INCLUDING THE CHARLESTON HARBOR FOR TONIGHT. TUESDAY THROUGH FRIDAY...SURFACE FLOW WILL BECOME QUITE LIGHT TUESDAY INTO MID WEEK...AS THE COASTAL WATERS REMAIN WITHIN A WEAK PRESSURE GRADIENT. LINGERING SWELL WILL KEEP SEAS IN THE OUTER GEORGIA WATERS WITHIN SMALL CRAFT ADVISORY RANGE THROUGH WEDNESDAY. THE MAIN MARINE CONCERN WILL CONTINUE TO BE SEA FOG. LIGHT SURFACE FLOW AND WARM MOIST AIR ACROSS THE COOL WATERS WILL CREATE AN IDEAL FOG ENVIRONMENT. MODELS CONTINUE TO SUPPORT A DIURNAL DEVELOPMENT PATTERN...WITH FOG DEVELOPING OVERNIGHT AND LINGERING OVER THE NEARSHORE WATERS THROUGH THE DAYTIME HOURS. FOG COULD BECOME DENSE AND CREATE HAZARDOUS CONDITIONS FOR MARINERS. WILL CONTINUE TO MENTION SEA FOG IN THE COASTAL WATERS FORECAST...AS WELL AS IN THE HAZARDOUS WEATHER OUTLOOK. HIGH PRESSURE WILL DEVELOP OVER THE ATLANTIC LATE WEDNESDAY...SETTING UP A SOUTHERLY FLOW COMPONENT ACROSS THE COASTAL WATERS THROUGH THE END OF THE WEEK. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. HIGH PRESSURE WILL GRADUALLY WEAKEN OVER THE ATLANTIC AND GULF OF MEXICO BY THE WEEKEND...WHICH WILL ALLOW A COLD FRONT TO APPROACH FROM THE NORTHWEST. && .HYDROLOGY... THE OHOOPEE RIVER AT REIDSVILLE HAS SURPASSED ACTION STAGE AND IS ABOUT 1/2 FT BELOW THE FLOOD STAGE OF 11 FT. THE STAGE AT 215 AM WAS 10.48 FT WHICH IS SLIGHTLY ABOVE THE RIVER FORECAST RECEIVED FROM THE SOUTHEAST RIVER FORECAST CENTER. DEPENDING ON TRENDS OVER THE NEXT FEW HOURS...WE MAY VERY WELL HAVE TO ISSUE A RIVER FLOOD WARNING. WILL COORDINATE WITH THE SOUTHEAST RIVER FORECAST CENTER LATER THIS MORNING. && .TIDES/COASTAL FLOODING... TIDES ARE RUNNING VERY NEAR PREDICTED LEVELS EARLY THIS MORNING. THE GFS-BASED EXTRATROPICAL STORM SURGE DATA SUGGESTS TIDES WILL FALL JUST SHORT OF COASTAL FLOOD ADVISORY CRITERIA...BUT GIVEN THE STRENGTH OF THE ONSHORE FLOW NOTED ALONG THE LOWER SOUTH CAROLINA COAST SUSPECT THIS MAY BE JUST ENOUGH TO BRING TIDE LEVELS NEAR 7.0 FT MLLW IN THE CHARLESTON HARBOR. WILL ISSUE A COASTAL FLOOD ADVISORY FROM 8 AM UNTIL NOON FOR ALL OF THE SOUTH CAROLINA COASTAL ZONES. ATTM WE BELIEVE TIDES WILL REMAIN BELOW ADVISORY THRESHOLDS ALONG THE NORTH GEORGIA COAST. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO NOON EST TODAY FOR SCZ048>051. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM EST TUESDAY FOR AMZ350-352. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS AFTERNOON FOR AMZ354. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM EST THURSDAY FOR AMZ374. && $$ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1233 AM EST MON DEC 15 2008 .SYNOPSIS... A WEAK COASTAL TROUGH WILL GRADUALLY MOVE INLAND OVERNIGHT AND DISSIPATE MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY INTO TUESDAY...STALL OUT NORTH OF THE AREA TUESDAY NIGHT THEN LIFT OFF TO THE NORTH WHILE HIGH PRESSURE RETURNS FOR WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT WILL APPROACH OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... COASTAL TROUGH IS PROGRESSING INLAND QUITE NICELY THIS EVENING BASED ON SFC ANALYSIS. WINDS OVER ALL MARINE LOCATIONS INCLUDING FOLLY BEACH ARE NOW REPORTING E TO SE WINDS HOWEVER INLAND OBS HAVE YET TO TURN. DEWPOINTS WILL SHOW A GRADUAL INCREASE OVERNIGHT AS THE COASTAL TROUGH CONTINUES TO WEAKEN AND SHIFT INLAND. CLOUD COVER WILL REMAIN THICK THROUGH THE REMAINDER OF THE NIGHT... PRECLUDING SIGNIFICANT FOG CONCERNS. HOWEVER PATCHY FOG IS STILL POSSIBLE JUST ABOUT ANYWHERE. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/... A POTENT COLD FRONT CROSSING THE MISS RIVER VALLEY WILL APPROACH THE APPALACHIANS MON WHILE THE COASTAL TROUGH DISSIPATES. THOUGH SOME ISENTROPIC LIFT IS EVIDENT ON SHORT TERM MODEL PROGS...IT IS BARELY ENOUGH TO PRODUCE ANY PRECIP DESPITE THE INCREASE IN LOW- MID LEVEL MOISTURE SO HAVE KEPT ONLY SLGT CHC POPS IN THE MORNING. THE CLOSING PROXIMITY OF THE FRONT WILL TRANSITION ATMOSPHERIC LIFT TO A PRE-FRONTAL NATURE BUT PRECIP LOOKS TO HAVE BETTER COVERAGE W OF THE CHS CWFA. HAVE NUDGED UP POPS INTO LOW CHC CATEGORY IN THE AFTN WHILE MOSTLY CLOUDY SKIES WILL PREVAIL. WARM AIR ADVECTION WILL CONTINUE ITS STRONG HOLD OVER THE AREA AHEAD OF THE FRONT...RAISING MAX TEMPS TO THE LOWER 70S. && .LONG TERM /TONIGHT THROUGH SUNDAY/... THE STRONG COLD FRONT WILL MOVE INTO THE APPALACHIANS BY MON NIGHT THEN STALL BEFORE COMPLETELY CROSSING THE RANGE TUE. THE FRONT WILL THEN BECOME HUNG UP OVER THE MOUNTAINS AS DEEP LAYERED RIDGING FROM THE GOMEX BULGES N AND KEEPS THE FRONT ALIGNED WITH THE UPPER LEVEL FLOW. WITH THE DEEP RIDGE TAPPING IN GULF MOISTURE DUE TO IT SW-NE FLOW ACRS THE AREA...LOW LEVEL MOISTURE WILL CONTINUE TO FLOW INTO THE AREA. THERE WILL STILL BE ENOUGH PRE-FRONTAL LIFT MON NIGHT THROUGH TUE NIGHT WHERE A FEW SHOWERS COULD FORM AND DRIFT FROM TIME TO TIME SO HAVE MAINTAINED A 20/30 POP SCHEME THROUGH TUE NIGHT. STARTING WED...THE FRONT WILL LIFT OFF TO THE N AS A WARM FRONT AND KEEP THE SOUTHEAST UNDER THE WARM BUBBLE OF HIGH PRESSURE THROUGH FRIDAY. THE DEEP RIDGE WILL SHIFT OFF TO THE E AND BREAK DOWN OVER THE WEEKEND...ALLOWING ANOTHER COLD FRONT TO MOVE INTO THE AREA AND POSSIBLY MOVE THROUGH THE SOUTHEASTERN STATES. ATTM...HAVE NOT GONE TOO HIGH WITH POPS BUT DID INTRODUCE SLGT CHC POPS TO REFLECT THE POTENTIAL FROPA. TEMPS WILL REMAIN WELL ABOVE NORMAL THROUGH MUCH OF THE WORKWEEK...WITH MAX TEMPS IN THE LOW-MID 70S AND MIN TEMPS IN THE MID 50S. OVER THE WEEKEND...AS THE FRONT MOVES THROUGH...ANOTHER ROUND OF COOLER AIR LOOKS TO MOVE INTO THE AREA BUT NOTHING TOO DRASTIC SO HAVE BROUGHT TEMPS BACK DOWN TO NEAR NORMAL LEVELS. THE ONLY OTHER CONCERN IN THE LONG TERM TIME-FRAME WILL BE NIGHTTIME FOG DEVELOPMENT DUE TO WEAK LLVL FLOW AND INCREASING LLVL MOISTURE. FOG LOOKS TO BE MORE WIDESPREAD...ESP NEAR THE COAST...WITH THE HIGHER DEWPOINT ADVECTION OVER THE COOLER SOIL TEMPS FOR MON NIGHT AND TUE NIGHT. THUS...HAVE MAINTAINED AREAS OF FOG WORDING WITH A 1SM QUALIFIER BUT WILL ALSO HAVE MENTION OF DENSE FOG POTENTIAL IN THE HAZARDOUS WX OUTLOOK. THERE IS A CHC THIS COULD ALSO PERSIST INTO WED NIGHT BUT WILL NEED TO SEE HOW THE FIRST FEW NIGHTS GO. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE NEXT 24 HOURS AT BOTH KCHS AND KSAV. THE LATEST RUC SUGGESTS THERE MAY BE SOME BRIEF CLEARING THAT OCCURS AROUND THE KSAV TERMINAL JUST PRIOR TO SUNRISE. SATELLITE DOES SHOW SOME BREAKS DEVELOPING IN THE CLOUD CANOPY ACROSS EASTERN FLORIDA AND THE ADJACENT ATLANTIC...SO THE RUC MAY VERY WELL BE ON TO SOMETHING. FOG COULD BECOME AN ISSUE UNDER THE CURRENT LIGHT WIND REGIME SHOULD THIS CLEARING MATERIALIZE. WILL INTRODUCE A TEMPO GROUND FOR 4SM BR BETWEEN 10-13Z AT KSAV TO HELP COVER THIS POSSIBILITY. ANY CLEARING THAT DOES OCCUR WILL BE SHORT LIVED WITH WEAK ISENTROPIC LIFT HELPING TO FILL THE CLOUD DECKS BACK IN LATER THIS MORNING. STRATUS AND FOG WILL LIKELY IMPACT BOTH TERMINALS AFTER 03Z TONIGHT AS AREAS OF SEA FOG MOVE INLAND. WILL ONLY SHOW A SLIGHT DETERIORATION AT KSAV WHERE MODELS HIT LOWEST CONDITIONS THROUGH 06Z BUT LIFR AND IFR CONDITIONS WILL LIKELY BE INTRODUCED TO BOTH TAF SITES WITH THE 12Z TAF CYCLE. EXTENDED AVIATION OUTLOOK...IFR OR LIFR CIGS/VSBYS ARE LIKELY MONDAY NIGHT THROUGH EARLY THURSDAY...ESPECIALLY IF SEA FOG AND/OR RADIATION FOG DEVELOPS. && .MARINE... WINDS HAVE TURNED E-SE AT ALL LOCATIONS THIS EVENING DUE TO THE COASTAL TROUGH AXIS SHIFTING TO THE COAST. WIND SPEEDS HAVE INCREASED A BIT ON THE OUTER PORTIONS...INCLUDING BUOY 41004 AND M2R6. THIS SHOULD HELP BRING HIGHER SEAS INTO INLAND PORTIONS...THUS THE ONGOING SMALL CRAFT FOR ALL REGIONS STILL LOOKS ON TRACK. THE COASTAL WATERS WILL REMAIN ALONG THE WESTERN PORTION OF THE SURFACE AND LOW LEVEL ATLC RIDGE MONDAY THROUGH WEDNESDAY...WHILE A BLOCKING RIDGE IN THE MID AND UPPER LEVELS PREVAILS OVER THE GULF AND SW ATLC. WHILE THE RIDGING BOTH SURFACE AND ALOFT DOES WEAKEN SOME THURSDAY/FRIDAY AND SHIFTS SLIGHTLY SOUTHWARD...THE BLOCKING PATTERN WILL HOLD FIRM THROUGH THE WEEK. THIS WILL PREVENT ANY COLD FRONT FROM PENETRATING THIS FAR SE THROUGH AT LEAST FRIDAY. THE END RESULT WILL BE FOR A SYNOPTIC PATTERN MORE TYPICAL OF THE WARMER MONTHS OF THE YEAR...SE TO SOUTH MONDAY AND TUESDAY...THEN SOUTH TO SW THEREAFTER. WIND FIELDS WILL BE NO MORE THAN 15 KT FOR MUCH OF MONDAY...THEN MAINLY 10 OR 10-15 KT AND LESS FOR THE REMAINDER OF THE WEEK. SEAS WILL TRANSITION FROM A COMBINATION OF WIND WAVE AND SWELL WAVE TONIGHT THROUGH MONDAY...TO MORE OF A SWELL WAVE MONDAY NIGHT THROUGH AT LEAST WEDNESDAY AND THURSDAY. WITH THE PERSISTENT ONSHORE FETCH THIS WILL KEEP SEAS ELEVATED...ENOUGH SO THAT SCA/S WILL CONTINUE FOR AMZ350-352-354 FOR SOME 6 FOOT SEAS OUT NEAR 20 NM OFF THE COAST INTO TUESDAY...AND ALSO SCA FOR AMZ374 WITH SEAS OF 6-7 FT THROUGH EARLY FRIDAY. SEA FOG...CONDITIONS APPEAR FAVORABLE FOR SEA FOG FORMATION MONDAY NIGHT THROUGH WEDNESDAY NIGHT OR THURSDAY WITH A LIGHT...WARM AND HUMID SOUTHERLY FLOW ADVECTING ACROSS THE RELATIVELY COOLER WATERS OF THE ATLC. AS DEW POINTS CLIMB INTO THE UPPER 50S AND LOWER 60S DURING THIS TIME IT WILL MOVE ACROSS WATERS THAT ARE IN THE MID AND UPPER 50S...LEADING TO THE POSSIBLE FORMATION OF DENSE SEA FOG. AS A RESULT...DENSE FOG ADVISORIES MAY BE REQUIRED FOR MUCH OF THE MARINE AREA DURING THE EARLY AND MIDDLE PARTS OF THE WEEK. && .TIDES/COASTAL FLOODING... TIDE LEVELS HAVE BEEN NEAR OR EVEN SLIGHTLY ABOVE PREDICTED LEVELS SINCE SATURDAY AFTERNOON...AND THIS IN SPITE OF THE OFFSHORE FETCH MUCH OF THIS TIME. IN WAKE OF THE TROUGH PASSING INLAND TONIGHT A MORE PRONOUNCED ONSHORE FETCH WILL DEVELOP IN TIME FOR THE HIGH TIDE CYCLE MONDAY MORNING AROUND 930 TO 1030 AM. THE GFS EXTRATROPICAL WATER LEVEL FORECAST SUGGESTS THAT TIDE LEVELS WILL FALL SHORT OF ANY SHALLOW COASTAL FLOODING CONCERNS WITH THAT HIGH TIDE...BUT GIVEN THE ONSHORE FLOW THE SITUATION WILL CONTINUE TO BE CAREFULLY MONITORED. DEPARTURES FOR SHALLOW COASTAL FLOODING NEED TO REACH ONLY 0.5 FT MLLW ABOVE PREDICTED LEVELS AT CHARLESTON MONDAY MORNING /WHICH SEEMS POSSIBLE/. BUT DEPARTURES NEED TO BE 0.8 FT MLLW ABOVE AT FORT PULASKI/SAVANNAH...WHICH AT PRESENT DOES NOT APPEAR LIKELY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR AMZ350-352-354. SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR AMZ374. && $$ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1258 AM EST MON DEC 15 2008 .AVIATION... MINOR CHANGES TO PREV TAFS. SPED UP FROPA A COUPLE HOURS BASED ON EXTRAPOLATION OF FRONT ACROSS NRN IL AND 00Z NAM GUIDANCE. RAIN ALONG AND AHEAD OF THE FRONT LOWERING FLYING CONDITIONS GENERALLY INTO MVFR RANGE. OBS UPSTREAM ALSO SUGGEST THAT A SHORT PD OF -FZRASNPL IS A GOOD POSSIBILITY BEFORE THE PRECIP TAPERS OFF TO FLURRIES BEHIND THE FRONT. STILL EXPECT MVFR CIGS TO PERSIST THROUGH THE DAY AND INTO THE EVE AS MOISTURE LAYER REMAINS TRAPPED BENEATH SUBSIDENCE INVERSION. && .PREV DISCUSSION... /ISSUED 831 PM EST SUN DEC 14 2008/ UPDATE... MAIN CONCERN ATTM IS PERIOD OF HEAVY FREEZING RAIN WHICH OCCURRED BEHIND THE CDFNT OVER ERN IA/NW IL THIS EVE. FORCING FOR POST FRONTAL PRECIP APPEARS TO BE A WK SHRTWV OVER NE FROM NEB/WRN IA WHICH IS EXPECTED TO LIFT NE INTO WI OVERNIGHT PROVIDING LESS POST FRONTAL PRECIP IN OUR AREA. THIS SCENARIO SUPPORTED BY 18Z NAM AND 21Z RUC WHICH BOTH SUGGEST THAT THIS HEAVY POST FRONTAL PRECIP WILL NOT TRANSLATE EWD INTO OUR CWA. STILL GIVEN ONGOING ZR OCCURRING BEHIND FRONT...FELT IT WAS WORTH ADDING A MENTION IN THE ZFP/GRIDS FOR WRN AREAS LATE TONIGHT. OTHER CONCERN IS WINDS WHICH HAVE BEEN BLO ADVISORY CRITERIA TODAY AND TONIGHT SO FAR. TEMPS HAVE BEEN CREEPING UP ALLOWING FOR A LITTLE BETTER MIXING OVERNIGHT THAN OCCURRED TODAY. FROPA SHOULD ALSO ENHANCE THE MIXING AND WITH WOLCOTT PROFILER SHOWING 65KT IN LOWEST GATE AT 01Z AM RELUCTANT TO DROP ADVISORY AND RATHER OPTED TO CONT IT. MINOR ADJUSTMENTS MADE TO TEMPS FOR CONTD SLOW RISING TREND UNTIL FROPA WHEN IN A PD OF 3-6HRS TEMPS SHOULD CRASH FROM U40S/L50S TO M-U20S. PREV DISCUSSION... /ISSUED 335 PM EST SUN DEC 14 2008/ SHORT TERM... TONIGHT THROUGH MONDAY NIGHT. STRONG COLD FRONT...NOW EXTENDING FROM EASTERN IOWA INTO NORTH CENTRAL OKLAHOMA...WILL CONTINUE TO MOVE EASTWARD TONIGHT AND SHOULD REACH OUR WESTERN ZONES LATE TONIGHT AND INTO EARLY MONDAY MORNING. PRECIPITATION HAS BEEN DECREASING ACROSS THE AREA THROUGH THIS AFTERNOON...BUT RE- DEVELOPMENT IS EXPECTED ALONG AND EAST OF THE FRONT. NOT MUCH IN THE WAY OF CHANGE EXPECTED FROM THE PREVIOUS FORECAST PACKAGE EXCEPT THAT GUIDANCE SUGGESTS LOW TEMPERATURES TOMORROW NIGHT SHOULD BE AT LEAST A CATEGORY LOWER THAN EARLIER ANTICIPATED. PRECIPITATION TIMING AND TYPE WILL BE THE BIGGEST PROBLEM WITH THIS FORECAST. UPSTREAM OBSERVATIONS INDICATE THAT THERE HAS BEEN A TRANSITION ZONE ASSOCIATED WITH THE FRONT. RAIN HAS BRIEFLY CHANGED TO FREEZING RAIN OR SLEET BEFORE CHANGING OVER TO SNOW. THIS TREND SHOULD CONTINUE AS THE BOUNDARY SWEEPS ACROSS THE AREA. THEREFORE... WE SHOULD SEE AN HOUR OR TWO WINDOW WHERE THERE IS SOME FREEZING RAIN OR SLEET EARLY MONDAY MORNING BEFORE CHANGING TO SNOW. AT THIS TIME...IT DOES NOT APPEAR THERE WILL BE SIGNIFICANT ICE ACCUMULATION SO NO ADVISORY IS NEEDED. HOWEVER...WILL NEED TO MONITOR FOR LATER TRENDS. WINDS WILL CONTINUE TO BE A PROBLEM. WINDS HAVE CALMED DOWN A LITTLE BIT THIS AFTERNOON...BUT SHOULD STRENGTHEN BACK UP AS THE FRONT APPROACHES. WILL LIKELY SEE ADVISORY LEVEL GUSTS. ALSO...THERE COULD BE A TIME OF BLOWING SNOW BEHIND THE FRONT BEFORE THE GRADIENT RELAXES BY TOMORROW AFTERNOON. LONG TERM... TUESDAY THROUGH SUNDAY. WINTRY MIX LATE TUESDAY INTO TUESDAY NIGHT... AT THIS POINT NOT A LOT OF CHANGES TO LONG TERM GRIDS WITH ACTIVE PATTERN TO CONTINUE THROUGH THE PERIOD. THE MAIN FOCUS WILL BE ON THE FIRST 24 TO 36 HOURS OF THE LONG TERM. FAST MOVING WAVE WILL MOVE ARRIVE INTO THE AREA BY AFTERNOON WITH PRECIP LIKELY RAPIDLY INCREASING TOWARDS EVENING. INCREASED POPS SOMEWHAT AND EXPANDED TO COVER THIS TREND. HAVE LEFT MIX BAG IN PLACE FOR TUESDAY NIGHT INTO EARLY WEDS. MODELS ALL SHOW A TONGUE OF WARM AIR ALOFT MOVING IN TO AT LEAST SOME OF THE CWA...ESPECIALLY SE QUARTER TO THIRD. SOME TRENDS OF MODELS SUGGESTING THAT WARM AIR MAY SNEAK FURTHER NORTH. THE MAJORITY OF THE 9Z SREF MEMBERS HAS TRANSITION AREA FROM PERU TO WARSAW TO SOUTH OF HILLSDALE WHERE A BIT OF EVERYTHING MAY OCCUR...MAINLY SNOW NORTH OF THIS AND POTENTIAL FOR HEADLINE SLEET/ICE ACCUMULATIONS IN THE SE. AT THIS POINT ENOUGH GOING ON PRIOR TO THIS SYSTEM AND STILL SOME UNCERTAINTY HOW THIS EVOLVES SO WILL MAKE SOME CHANGES TO THE HWO TO INCREASE AWARENESS A BIT MORE. AFTER THIS PERIOD THINGS BECOME EVEN MORE QUESTIONABLE WITH NEXT WAVE TO ARRIVE LATE WEDS NGT INTO THURS AND THURS NGT. MODELS VARY EVEN MORE THAN WITH FIRST MENTIONED SYSTEM WITH SOLUTIONS RANGING FROM SNOW FOR THE AREA...TO A MIXED BAG TO TEMPS WELL ABOVE FREEZING AND RAIN FOR THE AREA. AS A RESULT NO CHANGES MADE IN REGARDS TO THIS SYSTEM. YET ANOTHER ARCTIC BLAST MAY ARRIVE FOR THE END OF THE PERIOD RESULTING A CHANCE FOR SYNOPTIC SNOW FOLLOWED BY LAKE EFFECT PRECIP. WITH THE PATTERN SO CHAOTIC RIGHT NOW...FELT HOLDING A DRY FORECAST FOR SUNDAY WAS IN ORDER. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR INZ003>009-012>018-020-022>027-032>034. MI...WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ077>081. OH...WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-002-004- 005-015-016-024-025. LM...GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR LMZ043-046. && $$ SHORT TERM...REHBEIN LONG TERM...FISHER AVIATION...TAYLOR/SKIPPER UPDATE...TAYLOR in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 320 AM CST MON DEC 15 2008 .SHORT TERM...TODAY TEMP AND WIND TRENDS MAIN CONCERN TODAY. LATEST RUC/NAM RAW TEMPS ARE FAIRLY CLOSE TO REALITY THIS MORNING WHILE GFS IS TOO WARM. HAVE FOLLOWED RUC/NAM GIVING LITTLE REBOUND TODAY...AND HIGHS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. NAM MOS PLUS A FEW DEGREES. 07Z SFC ANLYS STILL SHOWS ANOTHER ISALLOBARIC MAX PASSAGE THROUGH IA SO EXPECT WINDS TO REMAIN CONSISTENT EARLY THIS MORNING...THEN DIMINISH SOMEWHAT LATER TODAY. HOWEVER WITH OUR ARCTIC AIRMASS IN PLACE IT WILL KEEP US IN WIND CHILL CRITERIA ALL BUT SERN SECTIONS TIL NOON...AND NRN THREE TIERS TIL MIDNIGHT. THUS WILL KEEP CURRENT HEADLINES IN PLACE...BUT EXTEND NRN ONE TIL 06Z. VSBYS HAVE BEEN A MILE OR LESS AT KEST THIS MORNING...AND OFTEN DOWN TO 1/4SM IN BLOWING SNOW...SO HAVE EXTENDED WINTER WX ADVY FOR BLOWING SNOW TIL 8AM. DOT ROAD REPORTS STILL SHOW LIMITED VSBYS IN THESE AREAS. SATELLITE AND MODEL TRENDS AS WELL AS MANUAL OBSERVATIONS WOULD INDICATE THAT AWOS/ASOS CIGS ARE TOO BULLISH ACROSS IA THIS MORNING LIKELY DUE TO BLOWING SNOW AND ELEVATED ICE CRYSTALS. THUS WILL GO WITH MORE SUNSHINE THAN NEPHANLYS WOULD EXPECT. .LONG TERM...TONIGHT THROUGH SUNDAY BRIEF PERIOD OF QUIET WEATHER GIVES WAY TO RATHER STRONG OVERRUNNING EVENT WITH MOISTURE TRANSPORT AND H850 FLOW LIFTING OVER A THE EXISTING BAROCLINIC ZONE FOR TUESDAY FOR A BROAD UPGLIDE...WITH H300 JET MAX OF 150 KTS ALSO AIDING BROAD AREA OF LIFT DURING THE DAYTIME HOURS. BUFKIT SOUNDINGS SUGGEST THAT FAIRLY UNIFORM CONDITIONS WILL TRANSLATE FROM SOUTHWEST IA THROUGH TO EASTERN SECTIONS BY EVENING. QUESTION OF THE DAY IS NOT SO MUCH THE SNOW:WATER RATIO...BUT THE AMOUNT OF QPF IS THE KEY. SO FAR THE EURO HAS BEEN CONSISTENT WITH PAST 4 OR MORE RUNS WITH NEARLY .40 TO .45 OF QPF. GFS/NAM HAVE BEEN SLIGHTLY LESS RELIABLE FROM RUN TO RUN BUT CONTINUE TO TREND A BIT LESS IN AVAILABLE MOISTURE. THE 00Z UKMET IS NEARER .30 TOTAL AS WELL. IN ANY EVENT IT LOOKS LIKE A PRETTY HIGH END ADVISORY FOR THE SOUTH TWO THIRDS OF THE FORECAST AREA WITH THE POSSIBILITY OF BREACHING 6+ INCH AMOUNTS SOMEWHERE SOUTH OF OF HIGHWAY 30. TIME CROSS SECTIONS SHOW FAIRLY GOOD LIFT IN THE DENDRITIC GROWTH ZONE FOR THE EVENT WHICH SHOULD LAST ABOUT 4 TO 6 HOURS ONCE IT BEGINS. THIS TRACKS FAIRLY WELL WITH ABOUT 1 INCH PER HOUR SNOWFALL RATES. AFTER SOME DELIBERATION HAVE DECIDED TO GO WITH A WATCH FOR TUESDAY FROM 12Z THROUGH 06Z WED. MOST OF THE SNOW WILL BE OVER WEST PRIOR TO 21Z BUT SHOULD CONTINUE INTO THE EVENING HOURS EAST. THOUGH BLOWING SNOW WILL NOT BE A PROBLEM SNOWFALL OF EVEN 4 TO 5 INCHES DURING THE DAY WILL CAUSE SOME PROBLEMS FOR AREA TRAVELERS. NEWEST 06Z NAM A BIT SLOWER THAN THE 00Z RUN...BUT TRENDS REMAIN APPROXIMATELY THE SAME. THE BULK OF THE SNOW WILL BE OVER BY THE EVENING HOURS AND SOME CLEARING EXPECTED BY MORNING. HAVE TRIMMED MINS WEST SECTIONS BASED ON THIS THINKING. QUICK BREAK FOR WED BEFORE THE NEXT UPSTREAM WAVE AFFECTS THE REGION FOR LATER ON THURSDAY. MODELS NOT IN GREAT AGREEMENT RIGHT NOW CONCERNING THE AMOUNT OF WARM AIR GETTING INTO THE SYSTEM. GFS MUCH WARMER THAN THE EURO...AND STRUCTURE OF THE SYSTEM IS MUCH DIFFERENT...FARTHER NORTH AND TRACK IS ALSO DIFFERENT. HAVE NOT MADE TOO MANY CHANGES TO GOING PTYPE AND POP GIVEN CURRENT UNCERTAINTY. THE EURO MAINTAINS A MORE SOUTHERLY TRACK AND IS ALSO A TOUCH SLOWER. THERE WILL BE ANOTHER SYSTEM BY LATE FRIDAY AND SATURDAY FOLLOWED BY A SHOT OF ARCTIC AIR ON THE WEEKEND. BOTH THE EURO AND GFS STILL AGREE ON OVERALL PATTERN IN THIS REGARD. && .AVIATION...15/06Z MAIN SHORT WAVES HAVE LIFTED NORTHEAST OF THE AREA WITH SOME -SHSN ACTIVTY AROUND...BUT NOTHING REAL SIG. MVFR CIGS THRU MUCH OF THE NGT WILL IMPV GRDLY FRM THE SW AS UPR SYS LIFTS OUT. GRAD WEAKENING MON AS HI PRES BLDS INTO THE AREA WITH DECENT VFR CONDS CONT INTO MON NGT. && .DMX WATCHES/WARNINGS/ADVISORIES... ...WIND CHILL ADVY TONIGHT THROUGH MIDDAY MONDAY /-18Z MONDAY/ SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD- CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS- POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA ADAIR-ADAMS-CLARKE-DECATUR-LUCAS-RINGGOLD-TAYLOR-UNION. ...WIND CHILL ADVY TONIGHT THROUGH TUESDAY EVENING /-06Z TUESDAY/ EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER. ...WINTER STORM WATCH TUESDAY MORNING THROUGH TUESDAY EVENING /12Z TUESDAY THROUGH 06Z WEDNESDAY/...FOR GREENE-BOONE-STORY-MARSHALL- TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON -WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR -RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS. && $$ SHORT TERM...BSS LONG TERM...REV AVIATION...MS DEC 08/BSS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1132 PM CST SUN DEC 14 2008 .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VERY LITTLE IN THE WAY OF AVIATION CONCERNS THROUGH THE NEXT 24 HOURS. EXTREMELY COLD ARCTIC AIRMASS CONTINUES TO SURGE INTO THE AREA. WHILE NORTH WINDS HAVE BEEN DECREASING OVER THE LAST COUPLE HOURS THEY WILL REMAIN GUSTY THROUGH AT LEAST 09Z. THEY WILL THEN SLOWLY VEER AROUND TO THE NORTHEAST AND THEN EAST BY THE LATE AFTERNOON HOURS. CONFIDENCE IS HIGH THAT CIGS WILL REMAIN ABOVE MVFR WITH KRSL AND KSLN REMAINING CLEAR THROUGH MOST OF THIS TAF PERIOD. A MID LEVEL CLOUD DECK WILL EVENTUALLY DEVELOP AFTER 00Z AS ISENTROPIC LIFT INCREASES. LAWSON && .PREV DISCUSSION... /ISSUED 913 PM CST SUN DEC 14 2008/ UPDATE... UPDATING TO TWEAK TEMPS DOWN AND TO ISSUE WIND CHILL ADVISORY FOR CENTRAL KS. POCKETS OF SLEET HAVE MOVED OFF INTO MO WITH JUST SOME VERY LIGHT SNOW/FLURRIES LEFT OVER SE KS. UPSTREAM TEMPS CONTINUE TO LOOK VERY COLD WITH WINDS STAYING UP OVER THE AREA. AFTER UPDATING TEMPS AND WINDS...WIND CHILL GRIDS NOW HAVE SEVERAL HOURS OF -15 TEMPS OVER CENTRAL KS. THEREFORE WILL GO AHEAD AND MATCH UP WITH SURROUNDING OFFICES AND ISSUE AN ADVISORY THROUGH 14Z. LAWSON PREV DISCUSSION... /ISSUED 708 PM CST SUN DEC 14 2008/ UPDATE... UPDATED TO INCREASE PRECIP CHANCES OVER SE KS AND TO DECREASE OVER CENTRAL AND SOUTH CENTRAL KS. PRECIP HAS INCREASED IN COVERAGE AND INTENSITY OVER SE KS. WE HAVE RECIEVED A COUPLE REPORTS OF THUNDER SLEET OVER THE LAST HOUR WITH SOME SNOW LIKELY MIXED IN. PROFILERS INDICATE THAT THE 850MB FRONT IS STILL MAKING ITS WAY THROUGH SE KS WITH SOME WARM ADVECTION ALSO INDICATED AT 700MB. IN ADDITION WATER VAPOR IMAGERY STILL SHOWING SOME WEAK UPPER ENERGY SLIDING THROUGH. THE GOOD NEWS IS THAT THIS ACTIVITY IS ON THE MOVE AND SHOULD EXIT SE KS BY AROUND 9 PM. TOOK OUT POPS FOR LOCATIONS ALONG AND WEST OF 135 AND JUST WENT WITH SOME FLURRIES THROUGH 06Z. LAWSON PREV DISCUSSION... /ISSUED 543 PM CST SUN DEC 14 2008/ AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS WILL BE SOME LIGHT PRECIP FOR THE FIRE FEW HOURS ALONG WITH SOME GUSTY NORTH WINDS. CURRENTLY HAVE SOME LIGHT SNOW...MIXING BRIEFLY WITH LIGHT SLEET...AFFECTING LOCATIONS GENERALLY ALONG AND EAST OF I-135. THIS ACTIVITY IS EXPECTED TO MOVE QUICKLY EAST AND BE OUT OF SE KS BY AROUND 03Z. CIGS ARE EXPECTED TO GRADUALLY RISE WITH ABOVE MVFR HEIGHTS EXPECTED. THE EXCEPTION WILL BE AT KCNU WHERE SOME MVFR CIGS WILL LAST THROUGH AROUND 03Z. WINDS ARE EXPECTED TO GRADUALLY DECREASE THROUGH THE NIGHT BUT WILL REMAIN OUT OF THE NORTH. LAWSON PREV DISCUSSION... /ISSUED 332 PM CST SUN DEC 14 2008/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE WIND CHILL VALUES TONIGHT AND SNOW CHANCES ACROSS CENTRAL KANSAS MONDAY NIGHT AND TUESDAY MORNING. THE NEXT CONCERN WILL BE THE FREEZING DRIZZLE AND FREEZING RAIN POTENTIAL WEDNESDAY NIGHT INTO THURSDAY MORNING. TONIGHT: LATEST WATER VAPOR LOOP WAS SHOWING THE POTENTIAL VORTICITY ANOMALY MOVING THROUGH NORTHWEST KANSAS. LATEST PROFILERS/RUC WERE ALSO SHOWING A BAROCLINIC ZONE AROUND 700MB NEAR THAT AREA. LATEST RADAR LOOP WAS ALSO SHOWING SOME NARROW BANDS OF LIGHT SNOW DEVELOPING ACROSS SOUTHWEST KANSAS EXTENDING INTO CENTRAL KANSAS. THESE INSTABILITY BANDS OF SNOW ARE ASSOCIATED WITH STEEPER LAPSE RATES ABOVE 750MB. THESE BANDS APPEARS TO FAIRLY PROGRESSIVE WHICH WILL LIMIT ANY SNOWFALL ACCUMULATION. AS A RESULT...WE HAVE LOWERED SNOWFALL ACCUMULATIONS TO ONE HALF INCH OR LESS THIS EVENING. MEANWHILE...MODELS CONTINUE TO UNDERESTIMATE THE AMOUNT OF COLD AIR POURING INTO THE AREA. AS A RESULT...WE HAVE LOWERED TEMPERATURES A COUPLE MORE DEGREES FOR OVERNIGHT LOWS. THESE LOWER TEMPERATURES COMBINED WITH GUSTY NORTH WINDS AT 10 TO 20 MPH WILL PRODUCE WIND CHILL VALUES NEAR 15 BELOW ZERO FOR A COUPLE OF HOURS OVERNIGHT IN RUSSELL AND LINCOLN COUNTIES. AFTER COLLABORATING WITH SURROUNDING FORECAST OFFICES...WE HAVE ELECTED NOT ISSUE A WIND CHILL ADVISORY. ALTHOUGH...LATER SHIFTS MAY NEED CONSIDER THIS DEPENDING IF TEMPERATURES DROP LOWER THAN THE CURRENT FORECAST. MONDAY: THE ARCTIC HIGH WILL CONTINUE TO SLIDE EAST INTO THE UPPER MIDWEST. HOWEVER...THE POLAR AIR MASS WILL NOT BUDGE WITH HIGHS STRUGGLING TO GET OUT OF THE TEENS. WIND CHILL VALUES WILL GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT-TUESDAY: ANOTHER POTENTIAL VORTICITY ANOMALY IS EXPECTED TO RIDE THROUGH NORTHWEST KANSAS AGAIN ON MONDAY NIGHT. THE GFS SEEMS TO HAVE A GOOD HANDLE ON THIS FEATURE WITH THE WAVE CURRENTLY MOVING THROUGH THE PACIFIC NORTHWEST. THIS FEATURE SHOULD PROVIDE AMPLE ISENTROPIC LIFT BETWEEN 290-295K MAINLY OVER NORTHERN KANSAS AND SOUTHERN NEBRASKA LATE MONDAY NIGHT. FORTUNATELY...IT APPEARS LIKE MOST OF THE ACTIVITY SHOULD BE OF THE FROZEN VARIETY. SNOWFALL ACCUMULATIONS SHOULD GENERALLY BE LESS THAN ONE INCH WITH THE HIGHEST AMOUNTS EXPECTED IN RUSSELL...LINCOLN AND SALINE COUNTIES. TUESDAY NIGHT-THURSDAY NIGHT: THE UPPER LEVEL FLOW IS PROGGED TO REMAIN OUT OF THE SOUTHWEST WHICH WILL PROVIDE AN UNSETTLED PATTERN DURING THIS TIMEFRAME. THE MAIN QUESTION WILL BE THE POSITION OF THE ELEVATED BAROCLINIC ZONE. RIGHT NOW WE ARE FAVORING MORE OF THE ECMWF/GFS ENSEMBLES ON THE TIMING OF THE FEATURES MOVING FROM THE ROCKIES AND NORTHERN PLAINS. THE ECMWF AND GFS ENSEMBLES ARE A LITTLE MORE AMPLIFIED WITH A WAVE MOVING THROUGH THE NORTHERN PLAINS ON LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THIS WAVE WILL JUST HELP SHOVE THE SURFACE FRONTAL BOUNDARY SOUTH THROUGH THE FORECAST AREA AND BRING A SHOT OF MODIFIED CANADIAN AIR WITH LITTLE IF ANY PRECIP. HOWEVER...THE GFS ENSEMBLES/ECMWF/UKMET ARE PICKING UP ON A STRONGER WAVE MOVING OUT OF THE ROCKIES WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS TRENDING ON PLACING THIS FRONTAL BOUNDARY FURTHER SOUTH THAN PREVIOUS RUNS. THIS WOULD FAVOR MORE OF A FREEZING RAIN EVENT IF THIS PANS OUT. THE GFS ON THE OTHER HAND...PLACES THIS BOUNDARY FURTHER NORTH BISECTING CENTRAL KANSAS. AT THIS TIME...WE ARE FAVORING THE ECMWF SOLUTION WHICH KEEPS THIS BOUNDARY FURTHER SOUTH WHILE CYCLOGENESIS GETS GOING ACROSS THE ROCKIES. THIS TIMEFRAME WILL NEED TO BE WATCHED WITH LATER RUNS. FRIDAY-SUNDAY: THE GFS/ECMWF ARE BOTH SHOWING A 1042MB HIGH DEVELOPING OVER ALASKA WHICH MAY BUILD SOUTH INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY. AS A RESULT...MORE COLD WEATHER IS ON THE HORIZON THIS WEEKEND. COX AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ARCTIC COLD FRONT WILL CONTINUE MOVING THROUGH SOUTHEAST KANSAS EARLY THIS AFTERNOON. BLUSTERY AND OCCASIONALLY STRONG NORTH TO NORTHWEST WINDS BEHIND THE FRONT WILL CONTINUE ACROSS MUCH OF THE AREA INTO THE EVENING. A NARROW AND TRANSIENT BAND OF LIFT IS EXPECTED TO DEVELOP BEHIND THE FRONT LATE THIS AFTERNOON ACROSS CENTRAL KANSAS AND SHIFT SOUTH ACROSS THE REST OF THE AREA INTO THE EARLY EVENING. THIS MAY RESULT IN A BRIEF PERIOD OF LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE. MVFR CIGS WILL PREVAIL ACROSS THE AREA FOR MUCH OF THE FORECAST VALID PERIOD. KED && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 6 19 13 26 / 10 10 20 20 HUTCHINSON 5 18 11 24 / 10 10 30 20 NEWTON 6 17 13 24 / 10 10 30 30 ELDORADO 8 18 13 25 / 20 10 20 30 WINFIELD-KWLD 10 20 15 29 / 10 10 20 20 RUSSELL 0 15 6 20 / 10 10 50 50 GREAT BEND 4 16 9 23 / 10 10 40 20 SALINA 2 16 8 22 / 10 10 40 50 MCPHERSON 5 17 10 24 / 10 10 30 40 COFFEYVILLE 12 24 15 30 / 70 10 20 30 CHANUTE 10 20 14 27 / 60 10 20 40 IOLA 9 19 13 26 / 60 10 20 40 PARSONS-KPPF 11 22 14 29 / 70 10 20 30 && .ICT WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 8 AM CST MONDAY FOR KSZ032-033-047>051. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 412 AM CST MON DEC 15 2008 .DISCUSSION... THE FORECAST CHALLENGES CENTER ON WIND CHILLS THE NEXT 18 HOURS...THOUGH ATTENTION IN FUTURE SHIFTS WILL BE TURNING TO TUES/TUES EVE SNOW EVENT AND THEN ANOTHER POSSIBLE ONE FOR THU. LATEST SURFACE ANALYSIS REVEALS 993MB LOW LIFTING NORTHEAST INTO CENTRAL ONTARIO. NEARLY 50MB DIFFERENCE BETWEEN THIS FEATURE AND ARCTIC HIGH PRESSURE CENTER EXPANDING OVER THE CTRL PLAINS. RESULTANT WINDS CONTINUE SUSTAINED AT 25 TO 30 MPH THIS MORNING WITH OCCASIONAL GUSTS TO 40 MPH. TEMPS CONTINUE TO FALL THROUGH THE SINGLE DIGITS BELOW ZERO WITH NEGATIVE DOUBLE DIGITS TO THE START THE DAY IN WEST CTRL MN. WIND CHILLS HAVE BEEN BETWEEN 25 AND 40 BELOW ZERO ACROSS THE AREA FROM EAST TO WEST THROUGH THE EARLY MORNING. OVERALL...AIR TEMPS ARE 35 TO 45 DEGREES COOLER ACROSS THE AREA THAN JUST 24 HOURS AGO! WHAT A CLASSIC EARLY WINTER CYCLONE. CURRENT WINDS SHOULD CONTINUE NEARLY THE SAME IN SPEED AND GUST THROUGH THE MORNING WITH AREA AND UPSTREAM WIND PROFILERS MEASURING 925MB WINDS AT 30 KTS AND RUC SOUNDINGS DIAGNOSING CONTINUED STEEP LOW LEVEL LAPSE RATES. THESE WINDS WILL VERY GRADUALLY EASE THIS AFTN AND WITH THAT THE BLOWING SNOW SHOULD TOO. 1000-850MB COLD AIR ADVECTION ALSO PROGGED TO ACCORDINGLY DIMINISH GRADUALLY. SO TEMPS ARE THOUGHT TO BE NEARLY STEADY THIS MORNING FOLLOWED BY CLIMBING A HANDFUL OF DEGREES THIS AFTN. WIND CHILLS THIS ENTIRE TIME THOUGH SHOULD REMAIN IN ADVISORY CRITERIA WITH WARNING CRITERIA CONTINUING ACROSS THE WEST. SO HAVE EXTENDED HEADLINES. WRN WI LIKELY TO CONTINUE WITH WIND INTO THIS EVE UNDER DEPARTING MSLP GRADIENT SO HAVE ADVISORY GOING TO MIDNIGHT IN THAT AREA. AIR TEMPS WILL BE VERY COLD TONIGHT AS THE ARCTIC HIGH OF 1040MB MAGNITUDE MOVES OVER THE SRN CWA. DIMINISHING WIND SPEEDS IN MN...CLEAR SKIES CWA WIDE...AND FRESH SNOW COVER IN MANY PLACES WILL RESULT IN AN IDEAL SETUP FOR PLUNGING TEMPS BETWEEN 7 PM AND 9 PM. NEGATIVE DOUBLE DIGITS LIKELY TO PREVAIL ACROSS MUCH OF THE MN CWA BY 9 PM. FRESH SNOW COVER EXPECTED TO HAVE A SEVERAL DEGREE IMPACT. RECENT LOCAL CLIMATOLOGICAL RESEARCH WITH A NIGHT AFTER A FRESH SNOW AND THESE SIMILAR SYNOPTIC CONDITIONS WOULD INDICATE NEAR -18F AT MSP. HAVE GONE JUST SLIGHTLY ABOVE THAT WITH SOME CIRRUS/CIRROSTRATUS EXPECTED VERY LATE. AREAS OF WEST CTRL MN WITH DEEP FRESH SNOW ARE EXPECTED TO DROP TO -23 TO -28. RECORD LOW MIN TEMP AT ST CLOUD FOR TUES MORNING IS -21 IN 1963 WHICH WILL BE IN GREAT JEOPARDY. ON THE IMMEDIATE HEALS OF THIS ARCTIC HIGH WILL COME A POTENT MID- LEVEL SHORT WAVE RIDING NORTHEAST WITHIN THE POWERFUL STATIONARY UPPER LEVEL JET TO OUR SOUTH ON TUES AND TUES NIGHT. VORT ADVECTION AND MID-LEVEL WARM AIR ADVECTION IS STRONG AND FOCUSED AHEAD OF THIS. THE 00Z AND 06Z NAM HAVE BEEN A BIT MORE POTENT WITH THIS...BUT BOTH THESE...THE 00Z GFS...AND 21Z SREF FAVOR AT LEAST SRN MN TO WRN WI TO BE UNDER A CORRIDOR OF SNOW DURING TUES AFTN AND EVE. WITH THE SNOW FALLING INTO A VERY COLD AIR MASS...RATIOS ARE LIKELY TO BE AT LEAST 17:1 IF NOT CONSIDERABLY HIGHER. FORECAST SNOWFALL TOTALS OF 2 TO 4 INCHES RIGHT NOW WOULD WARRANT AN ADVISORY AS TIME APPROACHES AND THE IMMEDIATE WIND CHILL CONCERNS END. THIS WILL HAVE TO BE WATCHED CLOSELY...AS FAVORABLE QUADRANT FOR STATIONARY BANDING MAY ENTER THE CWA AND INCREASE THOSE SNOWFALL AMOUNTS FROM ALBERT LEA...TO RED WING...TO EAU CLAIRE. ALSO POSSIBLE THAT ADVISORY AMOUNTS MAY NEED TO BE EXTENDED NORTHWARD TOWARDS THE TWIN CITIES...BUT AT THIS TIME UNCERTAINTIES REMAIN. ONE OF THOSE IS A WAVE ON THE POLAR JET TO OUR NORTH WHICH DOES MOVE IN DURING THE EVE. THE INFLUENCE THIS HAS ON THE SRN SHORT WAVE MAY ENHANCE AMOUNTS FURTHER NORTH DURING THE LATE AFTN AND EVE. HAVE FORECASTED SNOWFALL AMOUNTS RIGHT NOW IN THE ENVELOPE OF MOST CONFIDENCE WHICH CONTINUES TO INCREASE. AFTER THAT...A SYSTEM ON THU IN THE MIDDLE OF THE COUNTRY POTENTIALLY KEEPS OUR ONE SYSTEM-EVERY-36-HOUR PATTERN GOING STRONG. THIS SYSTEM IS THE BULK OF THE ENERGY OF THE NOW CLOSED LOW DROPPING SOUTHWARD OFF THE PACIFIC COAST THIS MORNING. MODELS HANDLE THIS CONSISTENTLY THROUGH THE FIRST 48 HOURS BUT THEN DIVERGE MID-WEEK IN THE RESPONSIVE LEE-CYCLOGENESIS. 00Z GFS WAS AN OUTLIER...BRINGING A LOW ON A VERY INTERESTING PATH FAVORING GOOD SNOW HERE. 00Z ECMWF ON THE OTHER HAND IS THE FURTHEST SOUTH BRINGING THE LOW INTO SRN IL AND GIVING US BASICALLY NOTHING. ENSEMBLE LEANS TOWARDS THE ECMWF WHICH HAS BEEN CONSISTENT AT KEEPING THE MAJORITY OF THE THE PRECIP FROM THIS SYSTEM TO OUR SOUTH. WILL HAVE TO WATCH CLOSELY BUT TOUGH AT THIS POINT TO GET A GOOD HANDLE ON THE GUIDANCE WITH THAT SYSTEM. HAVE GENERALLY KEPT THINGS AS IS WITH THE FORECAST DURING THU. OVERALL...BELOW NORMAL TEMPS TO PREVAIL THROUGH THE WEEK WITH ANOTHER COLD SHOT OF A POTENTIAL SIMILAR MAGNITUDE AS THIS CURRENT ONE BECOMING MORE LIKELY NEXT WEEKEND. && .AVIATION.../06Z TAF ISSUANCE/ VIGOROUS S/WV LIFTING ACROSS EASTERN AREAS NOW...WITH LIFR AND BRIEF +SN. THIS SHOULD LIFT NORTHEAST OUT OF EASTERN AREAS AFTER 08Z OR SO. SHOULD SEE SOME IMPROVEMENT IN CIGS ACROSS THE AREA...REMAINING MVFR IN CIGS/BLSN AT LEAST THROUGH THE OVERNIGHT. THEN DRIER ARCTIC AIR BUILDS INTO THE AREA AS SFC HIGH MOVES EAST. THIS SHOULD GRADUALLY DIMINISH NWLY SFC WNDS ACROSS THE AREA THROUGH 23Z. SKC/VFR BEFORE NEXT SHOT OF SNOW MOVING INTO THE AREA FOR TUE AFTN. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO- DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI- KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD- MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD- RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS- SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ANOKA- BENTON-BLUE EARTH-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN- GOODHUE-HENNEPIN-ISANTI-KANABEC-LE SUEUR-MCLEOD-MEEKER- MILLE LACS-MORRISON-NICOLLET-RAMSEY-RICE-SCOTT-SHERBURNE- SIBLEY-STEARNS-STEELE-WASECA-WASHINGTON-WRIGHT. WIND CHILL WARNING UNTIL 6 PM CST THIS AFTERNOON FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MARTIN-POPE- REDWOOD-RENVILLE-STEVENS-SWIFT-TODD-WATONWAN-YELLOW MEDICINE. WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BARRON- CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. && $$ MTF/DWE mn AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DULUTH MN 351 AM CST MON DEC 15 2008 ...WINTER STORM WINDS DOWN WITH LIGHT SNOW... .....EXCESSIVE COLD EXPECTED THIS WEEK... ......WIND CHILL ADVISORY TODAY AND TONIGHT... .DISCUSSION...SFC LOW HAS MOVED INTO SRN ONTARIO WITH CWA LEFT UNDER MASSIVE AREA OF ARCTIC AIR AND GUSTY WINDS. A SECONDARY SHORTWAVE EMBEDDED IN THE MID LVL TROF HAS EJECTED NORTHEAST THIS MORNING SPREADING ANOTHER ROUND OF LIGHT/MDT SNOW FROM THE TWIN PORTS INTO THE ARROWHEAD. IT APPEARS ONE MORE SHORTWAVE IS PUSHING ACROSS ERN SD INTO SW MN ACCORDING TO LATEST 11U/3.9U IMAGERY. LATEST RUC80 FCST OF THIS FEATURE SWINGS IT ACROSS CWA BY 18Z. WILL LET WSW CONTINUE AS LIGHT SNOW IS EXPECTED TO LINGER WITH GUSTY WINDS/BLOWING SNOW. AFTER WSW EXPIRES...WIND CHILL ADVISORY WILL BE IN EFFECT THROUGH 15Z TUESDAY. WINDCHILL VALUES ALREADY AT 30 TO 35 BELOW ACROSS MOST OF MN ZONES AND 15 TO 25 BELOW ACROSS WISC. MAIN STORY WILL BE COLD AIR AND WINDCHILLS THROUGH THE WEEK. MAY NEED TO UPGRADE WCA TO WIND CHILL WARNING TONIGHT ACROSS RANGE/ARROWHEAD. MAV GUIDANCE HAS BEEN TOO WARM SO FAR WITH THIS OUTBREAK AND THIS TYPICALLY IS THE CASE. MET NUMBERS A BIT BETTER. SUSPECT CLEARING WILL OCCUR TONIGHT HOWEVER RADIATIONAL COOLING CONDITIONS ARE NOT OPTIMAL. WINDS IN SFC/925 LAYER STILL BRISK WITH LINGERING PRESS GRADIENT. ALSO...WITH LACK OF SHARP RIDGE AXIS ALOFT MAY SEE SOME CLOUDS SNEAKING IN FROM THE NRN PLAINS. REGARDLESS...STILL EXPECT TONIGH TO BE COLDEST NIGHT OF THIS SEASON SO FAR. ANOTHER ROUND OF LIGHT SNOW WILL SPREAD INTO REGION TUESDAY...PRIMARILY ACROSS SRN HALF OF CWA. GOOD MDL AGREEMENT ON THIS SYSTEM WITH 1 TO 2 INCH SNOWFALL EXPECTED. LONG TERM... MED RANGE MODELS DIVERGE AFTER MID WEEK...WITH GFS BRINGING A STRONG SHORTWAVE AND SFC LOW PRES INTO SRN WI ON THURS. GFS LACKS SUPPORT OF BOTH ECMWF AND GEM GLOBAL HOWEVER...KEEPING THE SYSTEM SOUTH INTO THE OHIO VALLEY DUE TO STRONG ARCTIC HIGH PRES RIDGING INTO WRN ONT. DECIDED TO LEAN TOWARDS THE LATTER SOLUTION...BACKING POPS TO THE LOW CHANCE CATEGORY THUR/THUR NIGHT. BETTER CHANCE OF SNOW BY FRI NIGHT INTO SAT AS FLOW BECOMES SWRLY AHEAD OF BROAD MID LEVEL TROUGH EJECTING OUT OF THE ROCKIES. TEMPERATURES WILL REMAIN MUCH BELOW SEASONAL NORMS THROUGH THE NEXT WEEK WITH ANOTHER POTENTIAL ARCTIC OUTBREAK BY THE WEEKEND. && .AVIATION... VSBYS WILL REMAIN IN THE IFR RANGE THROUGH THE MORNING DUE TO BLSN AND -SN...WHILE CIGS WILL GENERALLY BE IN THE MVFR RANGE. GUSTY NW WINDS WILL SLOWLY DIMINISH AND BACK THIS AFTERNOON... PUTTING AN END TO THE BLSN...EXCEPT IN KDLH...WHERE WINDS WILL REMAIN GUSTY THROUGH THE EARLY EVENING HOURS. && POINT TEMPS/POPS... DLH -5 -23 -7 -8 / 50 10 20 70 INL -4 -31 -9 -11 / 60 10 10 60 BRD -7 -22 -3 -10 / 20 10 30 60 HYR -4 -23 -1 -9 / 30 10 50 70 ASX 1 -18 2 -1 / 70 10 20 70 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 4 AM CST EARLY THIS MORNING FOR CROW WING-PINE-SOUTHERN AITKIN-SOUTHERN CASS. WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WINTER STORM WARNING UNTIL NOON CST TODAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS-KOOCHICHING-NORTHERN AITKIN- NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA- NORTHERN ST. LOUIS-SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA- SOUTHERN LAKE/LAKESHORE. WIND CHILL ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS-KOOCHICHING- NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE- NORTHERN ITASCA-NORTHERN ST. LOUIS-SOUTHERN COOK/LAKESHORE- SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WI...WINTER STORM WARNING UNTIL 4 AM CST EARLY THIS MORNING FOR BURNETT-SAWYER-WASHBURN. WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR BURNETT-PRICE- SAWYER-WASHBURN. WINTER STORM WARNING UNTIL NOON CST TODAY FOR ASHLAND-BAYFIELD- DOUGLAS-IRON. WIND CHILL ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR ASHLAND-BAYFIELD-DOUGLAS-IRON. WINTER WEATHER ADVISORY UNTIL 4 AM CST EARLY THIS MORNING FOR PRICE. LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121- LSZ144-LSZ145-LSZ148. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM CST TUESDAY FOR LSZ146-LSZ147. GALE WARNING UNTIL 4 PM CST THIS AFTERNOON FOR LSZ146-LSZ147. SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ140- LSZ141-LSZ142-LSZ143. $$ CANNON/TL mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 950 AM EST MON DEC 15 2008 .SYNOPSIS/DISCUSSION... 14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING A SPLIT UPPER LEVEL PATTERN ACROSS THE NATION THIS MORNING. NORTHERN STREAM FLOW HAS DUG A SIGNIFICANT LONGWAVE TROUGH ACROSS MUCH OF THE WEST AND INTO THE CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST. TREMENDOUS COLD AIR HAS SPILLED OUT OF SOUTHERN CANADA INTO PORTIONS OF THE NORTHERN/CENTRAL U.S. WITH THIS TROUGH. CURRENT AIR TEMPS FROM MONTANA TO COLORADO EASTWARD TO THE MIDDLE MS VALLEY AND NORTH TO THE WESTERN GREAT LAKES ARE WELL BELOW ZERO WITH MANY SPOTS 15 TO 25 DEGREES INTO THE NEGATIVE. THIS DOES NOT EVEN TAKE INTO ACCOUNT WIND CHILL WHICH IS DIPPING DOWN BETWEEN 30 AND 40 BELOW IN SPOTS (BRRRR!). CONDITIONS ARE RADICALLY DIFFERENT FURTHER TO THE SOUTHEAST WITH LONGWAVE RIDGING BUILDING OVER THE GULF COAST AND EVENTUALLY THE REST OF THE SOUTHEAST. SOUTHERN STREAM FLOW RUNNING NORTHEAST FROM MEXICO AND ACROSS AL/GA CONTINUES TO PROVIDE ABUNDANT MID/HIGH LEVEL MOISTURE. AT THE SURFACE...FORECAST AREA REMAINS IN A MOIST SOUTHEAST FLOW PATTERN BETWEEN HIGH PRESSURE OFF THE MID-ATLANTIC COAST AND A COLD FRONT CHARGING SOUTH THROUGH THE TENNESSEE AND SOUTHERN MS VALLEYS. THIS COLD FRONT IS THE DIVIDE BETWEEN THE BALMY AIRMASS IN PLACE ALONG THE NORTHEAST GULF COAST AND THE FRIGID ARCTIC AIR TO THE NORTHWEST. PRETTY INCREDIBLE TEMPERATURE DROPS BEING OBSERVED THIS MORNING BEHIND THE FRONT. STATIONS ACROSS SOUTHEAST MISSOURI WHERE SITTING IN THE LOWER 60S EARLIER THIS MORNING AND JUST A FEW HOURS LATER ARE PLUNGING THROUGH THE TEENS WITH SNOW FALLING! ALTHOUGH IT IS A BIT SCARY TO SEE THIS FRONT STILL CHARGING SOUTHEAST...IT WILL NEVER REACH OUR AREA. STRONG RIDGING TO OUR SOUTH IS UNANIMOUSLY PROGGED BY GUIDANCE TO STALL THE FRONT IN ITS TRACKS LATER TODAY AND TONIGHT JUST TO OUR NORTH AND WEST. IN THE PRE-FRONTAL ENVIRONMENT WE ARE SEEING TEMPERATURES ACROSS THE AREA RISING THROUGH THE UPPER 50S AND 60S. SKIES ARE ON THE MOSTLY CLOUDY SIDE ACROSS TH WEST AND NORTH WITH A BAND OF PARTLY TO MOSTLY SUNNY SKIES ACROSS THE SUWANNEE RIVER VALLEY. SKY COVER THROUGH THE REMAINDER OF THE DAY WILL BE VARIABLE WITH A TENDENCY TOWARD MOSTLY CLOUDY CONDITIONS...ESPECIALLY ACROSS THE WEST. COLD FRONT WILL BE DROPPING INTO CENTRAL MS/NORTHERN AL DURING THE AFTERNOON. LOW LEVEL FOCUS AHEAD OF THIS FRONT IS COMBINING WITH DEEP LAYER ISENTROPIC UPGLIDE AND SOME ADDITIONAL WEAK SYNOPTIC SUPPORT FROM A SERIES OF SOUTHERN STREAM IMPULSES TO SUPPORT A SCATTERING OF SHOWERS ACROSS AL THIS MORNING. AS THE FRONT EDGES CLOSER WE MAY SEE A FEW OF THESE SHOWERS REACHING THE EASTERN FL PANHANDLE AND SOUTHEAST ALABAMA THIS AFTERNOON/EVENING. HOWEVER... MUCH OF THE DAY WILL BE DRY AND ACCUMULATIONS SHOULD BE LIGHT. WEAK SURFACE TROUGH FROM OUR EASTERN COASTAL WATERS ACROSS NORTHEAST FLORIDA IS ALSO SUPPORTING A FEW ISOLATED SHOWERS. ONE OR TWO OF THESE MAY REACH THE FLORIDA BIG BEND/SOUTH-CENTRAL GA THIS AFTERNOON BUT SHOULD NOT AMOUNT TO MUCH WITH VERY LIMITED IMPACT TO ANY OUTDOOR ACTIVITIES. COLD FRONT REMAINS STALLED TO OUR NORTHWEST TONIGHT. A FEW WIDELY SCATTERED SHOWERS CAN STILL NOT BE RULED OUT ACROSS THE PANHANDLE AND SOUTHEAST AL/SOUTHWEST GA ALONG AND AHEAD OF THIS BOUNDARY...BUT DURATIONS SHOULD BE SHORT AND ACCUMULATIONS LIGHT. VERY WARM NIGHT FOR MID-DECEMBER IS STORE WITH MIDDLE AND UPPER 50S COMMON INLAND AND LOWER TO MIDDLE 60S AT THE COAST. && .MARINE...WINDS AND SEAS HAVE GENERALLY FALLEN BELOW EXERCISE CAUTION CONDITIONS AND WILL TAKE THE HEADLINE OUT OF THE WESTERN LEGS WITH THE MORNING UPDATE. THIS GRADIENT WILL LOOSEN FURTHER TONIGHT AS A COLD FRONT STALLS WELL NORTH OF THE FORECAST WATERS. A DECREASE IN WINDS AND SEAS WILL CONTINUE THROUGHOUT THE BALANCE OF THE WORK WEEK AS SURFACE RIDGING BUILDS OVER THE NORTHEAST GULF OF MEXICO. && .AVIATION... HIS MORNINGS FOG HAS DISSIPATED AND CEILINGS ARE IN VFR CATEGORY WITH BROKEN LAYERS BETWEEN 6KFT AND 9KFT. VFR THROUGH DAY AND EVENING THEN SOME IFR CONDITIONS LIKELY AT TLH VLD AND ABY BY MORNING AS SOME FOG AND LOW STRATUS DEVELOPS. && .FIRE WEATHER...WITH PLENTY OF LOW LEVEL MOISTURE BEING ADVECTED IN THROUGHOUT THE WEEK...NO FIRE WEATHER CONCERNS ARE EXPECTED. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 75 55 77 56 79 / 10 05 05 05 05 PANAMA CITY 74 60 75 60 77 / 20 05 10 05 05 DOTHAN 67 57 75 57 77 / 30 05 10 10 05 ALBANY 70 56 75 56 77 / 30 05 10 10 05 VALDOSTA 75 55 76 54 79 / 10 05 05 05 05 CROSS CITY 78 57 78 53 80 / 10 05 05 05 05 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ AVIATION...GOREE SYNOPSIS/DISCUSSION/MARINE...MROCZKA FIRE WEATHER...GOULD fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 538 AM EST MON DEC 15 2008 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY INTO TUESDAY...STALLING OUT NORTH OF THE AREA TUESDAY NIGHT. THE FRONT WILL LIFT OFF TO THE NORTH WHILE HIGH PRESSURE RETURNS WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT WILL APPROACH OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURFACE OBSERVATIONS SUGGEST THE COASTAL TROUGH HAS DISSIPATED WITH ONLY A SUBTLE INVERTED KINK NOTED IN THE ISOBARS JUST INLAND FROM THE COAST. HOWEVER ONGOING WEAK ISENTROPIC LIFT/WARM AIR ADVECTION CONTINUES TO PRODUCE AN EXTENSIVE MID-LEVEL CLOUD DECK ACROSS MUCH OF THE REGION WITH CEILINGS GENERALLY AROUND 7000 FT. THE KCLX RADAR IS EVEN PICKING UP ON SOME ISOLATED SHOWER ACTIVITY ACROSS THE ATLANTIC CENTERED ABOUT 30 NM SOUTHEAST OF HUNTING ISLAND. ONE OR TWO OF THESE SHOWERS COULD MOVE ONSHORE BETWEEN OSSABAW SOUND AND SULLIVANS ISLAND OVER THE NEXT FEW HOURS BUT MOST AREAS WILL REMAIN DRY THROUGH SUNRISE. THE WEAK INSITU WEDGE THAT IS PLACE ACROSS THE MIDLANDS WILL STEADILY DECAY THIS MORNING AS PARENT HIGH PRESSURE SHIFTS SHIFTS EVEN FARTHER OUT IN THE OPEN ATLANTIC. MODELS SUGGEST SOME WEAK ISENTROPIC LIFT ALONG THE 290-300K SURFACES WILL PERSIST THROUGH MUCH OF THE DAY...HOWEVER EXTENSIVE DRY AIR ABOVE 700MB SHOULD KEEP ANY ASSOCIATED SHOWER ACTIVITY FAIRLY ISOLATED. WILL KEEP SLIGHT CHANCE POPS IN PLACE FOR THE ENTIRE FORECAST AREA BUT CONFIDENCE ON ANY ONE LOCATION RECEIVING MEASURABLE RAINFALL IS LOW GIVEN THE LESS THAN FAVORABLE MOISTURE PARAMETERS THAT ARE IN PLACE. TEMPERATURES SHOULD BE A SOLID 10 DEGREES WARMER THAN SUNDAY DESPITE EXTENSIVE CLOUD COVER. EXPECT HIGHS TO REACH THE LOWER 70S EXCEPT NEAR THE COAST WHERE ONSHORE TRAJECTORIES ACROSS LOWER TO MID 50 WATER TEMPERATURES WILL KEEP THE BEACHES CONSIDERABLY COOLER. SHOULD SEE PATCHES OF DENSE SEA FOG DEVELOP ACROSS THE WATERS THIS AFTERNOON AS DEWPOINTS OVER THE ATLANTIC RISE INTO THE MID 60S. SOME OF THIS FOG COULD IMPACT THE BEACHES LATE IN THE AFTERNOON IN THE CONTINUED ONSHORE FLOW. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... THE MAIN CONCERN FOR TONIGHT IS THE POTENTIAL FOR DENSE SEA FOG TO MOVE INLAND FROM OFF THE ATLANTIC. DEWPOINTS ARE FORECAST TO RISE INTO THE MID 60S BY LATE AFTERNOON AND PERSIST THROUGH THE NIGHT. SATELLITE DERIVED AND OBSERVED SEA SURFACE DATA INDICATE WATER TEMPERATURES ARE IN THE LOWER TO MID 50S FROM THE SURF ZONE OUT TO AT LEAST 20 NM AND AS HIGHER DEWPOINTS BEGIN TO OVERSPREAD THESE COOL NEARSHORE WATERS EXPECT AREAS OF DENSE FOG TO MATERIALIZE. ANY FOG BANKS THAT FORM SHOULD ADVECT SLOWLY INLAND THIS EVENING UNDER LIGHT SOUTHEAST BOUNDARY LAYER FLOW. ITS A TOUCH CALL ON EXACTLY HOW FAR INLAND THE FOG WILL MIGRATE BUT 03Z SREF VISIBILITY GUIDANCE AS WELL AS THE NAM AND GFS MOS PACKAGES ALL SUGGEST THE FOG WILL PENETRATE INTO AT LEAST THE EASTERN MIDLANDS AND CSRA. WILL KEEP AREAS OF FOG IN THE FORECAST INLAND BUT INTRODUCE DENSE FOG WORDING FOR THE COASTAL ZONES WHERE CONFIDENCE IS HIGHER THAT VISIBILITIES TO DROP TO 1/4 MILE OR LESS. THE DAY SHIFT MAY NEED TO EXPAND THE DENSE FOG WORDING MUCH FARTHER INLAND PENDING 12Z AND 18Z MODEL TRENDS. A DENSE FOG ADVISORY MAY VERY WELL BE NEEDED FOR PORTIONS OF THE FORECAST AREA TONIGHT AND THIS WILL BE RELAYED IN THE MORNING HAZARDOUS WEATHER OUTLOOK. ANY LINGERING ISENTROPIC LIFT WILL BE CONFINED TO EASTERN HALF OF THE FORECAST AREA THIS EVENING BEFORE SHIFTING FARTHER NORTH INTO THE CHARLESTON TRI-COUNTY AREA AFTER MIDNIGHT. WILL KEEP A SLIGHT CHANCE FOR SHOWERS IN THESE AREAS. LOWS WILL RANGE FROM THE LOWER 50S INLAND TO THE UPPER 50S/NEAR 60 AT THE BEACHES. && .LONG TERM /TUESDAY THROUGH SUNDAY/... LATEST MODEL SOLUTIONS CONTINUE TO INDICATE THE COLD FRONT BECOMING STALLED TO THE NORTH AND WEST OF THE FORECAST AREA ON TUESDAY...AS HIGH PRESSURE ALOFT RIDGES NORTHWARD. LACKING ANY STRONG FORCING MECHANISMS...RAIN LOOKS LESS LIKELY ON TUESDAY. HAVE LIMITED RAIN CHANCES TO ONLY A SLIGHT CHANCE OVER THE MARINE ZONES AND NORTHERN SOUTH CAROLINA COUNTIES...CLOSEST TO THE SAGGING FRONT AND A WEAK TROUGH OVER THE WATERS. CONDITIONS CONTINUE TO APPEAR FAVORABLE FOR FOG DEVELOPMENT TUESDAY INTO WEDNESDAY...DUE TO THE COMBINATION OF WEAK SURFACE FLOW AND DECENT LOW LEVEL MOISTURE. SREF VISIBILITIES CONFIRM A DIURNAL PATTERN OF FOG DEVELOPMENT OVER LAND AND SEA AT NIGHT...THEN LINGERING IN THE NEARSHORE WATERS DURING THE DAYTIME HOURS. HAVE MAINTAINED FOG WORDING IN THE FORECAST AND WILL CONTINUE MENTION OF DENSE FOG POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. THE LINGERING FRONT TO THE NORTH WILL LIFT FURTHER AWAY FROM THE AREA ON WEDNESDAY...WHILE SURFACE HIGH PRESSURE BUILDS OVER THE ATLANTIC AND SOUTHEAST STATES. THE REGION WILL THUS REMAIN WITHIN SOUTHERLY FLOW THROUGH FRIDAY...KEEPING TEMPERATURES WELL ABOVE NORMAL THROUGH THE WEEK. EXPECT HIGH TEMPERATURES TO REACH THE MID TO UPPER 70S BY THURSDAY AND FRIDAY. RIDGING AT THE SURFACE AND ALOFT WILL DIMINISH OVER THE WEEKEND...ALLOWING ANOTHER COLD FRONT TO APPROACH THE REGION FROM THE NORTHWEST. GFS SUGGESTS THAT THE REMNANT RIDGING COULD BE SUFFICIENT TO STALL THE FRONT TO THE NORTH AGAIN. HOWEVER BOTH ECMWF AND GFS MODEL RUNS INDICATE A STRONGER SECOND FRONT PUSHING INTO THE FORECAST AREA LATE IN THE WEEKEND/EARLY NEXT WEEK THAT COULD BRING A BETTER CHANCE OF RAIN AND COOLER TEMPERATURES. HAVE THUS INCLUDED SLIGHT CHANCE POPS WITH A COOLING TREND SATURDAY AND SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE NEXT 24 HOURS AT BOTH KCHS AND KSAV. THE LATEST RUC SUGGESTS THERE MAY BE SOME BRIEF CLEARING THAT OCCURS AROUND THE KSAV TERMINAL JUST PRIOR TO SUNRISE. SATELLITE DOES SHOW SOME BREAKS DEVELOPING IN THE CLOUD CANOPY ACROSS EASTERN FLORIDA AND THE ADJACENT ATLANTIC...SO THE RUC MAY VERY WELL BE ON TO SOMETHING. FOG COULD BECOME AN ISSUE UNDER THE CURRENT LIGHT WIND REGIME SHOULD THIS CLEARING MATERIALIZE. WILL INTRODUCE A TEMPO GROUND FOR 4SM BR BETWEEN 10-13Z AT KSAV TO HELP COVER THIS POSSIBILITY. ANY CLEARING THAT DOES OCCUR WILL BE SHORT LIVED WITH WEAK ISENTROPIC LIFT HELPING TO FILL THE CLOUD DECKS BACK IN LATER THIS MORNING. STRATUS AND FOG WILL LIKELY IMPACT BOTH TERMINALS AFTER 03Z TONIGHT AS AREAS OF SEA FOG MOVE INLAND. WILL ONLY SHOW A SLIGHT DETERIORATION AT KSAV WHERE MODELS HIT LOWEST CONDITIONS THROUGH 06Z BUT LIFR AND IFR CONDITIONS WILL LIKELY BE INTRODUCED TO BOTH TAF SITES WITH THE 12Z TAF CYCLE. EXTENDED AVIATION OUTLOOK...IFR OR LIFR CIGS/VSBYS ARE LIKELY MONDAY NIGHT THROUGH EARLY THURSDAY...ESPECIALLY IF SEA FOG AND/OR RADIATION FOG DEVELOPS. && .MARINE... WINDS HAVE FINALLY BECOME SOUTHEAST ACROSS THE ENTIRE MARINE AREA NOW THAT THE COASTAL TROUGH HAS MOVED INLAND AND DISSIPATED. SOUTHEAST WINDS WILL CONTINUE THROUGH THIS EVENING BEFORE SLOWLY VEERING MORE SOUTHERLY AFTER MIDNIGHT. REGIONAL BUOYS INDICATE EASTERLY SWELLS WITH PERIODS OF 8-9 SECONDS ARE KEEPING SEAS FAIRLY ENHANCED WITH COMBINED SEAS OF 4-6 FT ACROSS THE NEARSHORE WATERS AND 5-7 FT ACROSS THE GEORGIA OFFSHORE LEG. WW4 KEEPS THESE SWELLS IN PLACE THROUGH TONIGHT THUS SMALL CRAFT ADVISORIES WILL BE MAINTAINED FOR ALL BUT THE CHARLESTON HARBOR. THE MAIN CONCERN FOR LATE THIS AFTERNOON INTO TONIGHT IS POTENTIAL DEVELOPMENT OF DENSE SEA FOG. LOWER TO MID 60 DEWPOINTS ADVECTING OVER WATER TEMPERATURES IN THE LOWER TO MID 50S SUGGEST THE POTENTIAL FOR DENSE SEA FOG DEVELOPMENT IS RATHER HIGH. COULD SEE AT LEAST PATCHY FOG DEVELOP ACROSS THE WATERS AS EARLY AS THIS AFTERNOON BEFORE BECOME MORE WIDESPREAD THIS EVENING AND OVERNIGHT AS THE FOG BANK SPREADS INLAND. WILL INTRODUCE MENTION OF AREAS OF DENSE FOG WITH VISIBILITIES 1/4NM OR LESS. A MARINE DENSE FOG ADVISORY WILL LIKELY BE NEEDED FOR THE NEARSHORE WATERS INCLUDING THE CHARLESTON HARBOR FOR TONIGHT. TUESDAY THROUGH FRIDAY...SURFACE FLOW WILL BECOME QUITE LIGHT TUESDAY INTO MID WEEK...AS THE COASTAL WATERS REMAIN WITHIN A WEAK PRESSURE GRADIENT. LINGERING SWELL WILL KEEP SEAS IN THE OUTER GEORGIA WATERS WITHIN SMALL CRAFT ADVISORY RANGE THROUGH WEDNESDAY. THE MAIN MARINE CONCERN WILL CONTINUE TO BE SEA FOG. LIGHT SURFACE FLOW AND WARM MOIST AIR ACROSS THE COOL WATERS WILL CREATE AN IDEAL FOG ENVIRONMENT. MODELS CONTINUE TO SUPPORT A DIURNAL DEVELOPMENT PATTERN...WITH FOG DEVELOPING OVERNIGHT AND LINGERING OVER THE NEARSHORE WATERS THROUGH THE DAYTIME HOURS. FOG COULD BECOME DENSE AND CREATE HAZARDOUS CONDITIONS FOR MARINERS. WILL CONTINUE TO MENTION SEA FOG IN THE COASTAL WATERS FORECAST...AS WELL AS IN THE HAZARDOUS WEATHER OUTLOOK. HIGH PRESSURE WILL DEVELOP OVER THE ATLANTIC LATE WEDNESDAY...SETTING UP A SOUTHERLY FLOW COMPONENT ACROSS THE COASTAL WATERS THROUGH THE END OF THE WEEK. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. HIGH PRESSURE WILL GRADUALLY WEAKEN OVER THE ATLANTIC AND GULF OF MEXICO BY THE WEEKEND...WHICH WILL ALLOW A COLD FRONT TO APPROACH FROM THE NORTHWEST. && .HYDROLOGY... HAVE GONE AHEAD AND ISSUED A RIVER FLOOD WARNING FOR THE OHOOPEE RIVER AT REIDSVILLE. AT 515 AM THE STAGE WAS 10.75 FT AND RISING. CURRENT PROJECTIONS TAKE THE RIVER INTO FLOOD AROUND SUNRISE /FLOOD STAGE IS 11 FT/. HAVE MANUALLY ADJUSTED THE SOUTHEAST RIVER FORECAST CENTER/S FORECAST GUIDANCE FROM YESTERDAY EVENING TO FIT OUR CURRENT THINKING. THE SOUTHEAST RIVER FORECAST CENTER DOES NOT OPEN UNTIL 6 AM SO WILL COORDINATE WITH THEM THEN. && .TIDES/COASTAL FLOODING... TIDES ARE RUNNING VERY NEAR PREDICTED LEVELS EARLY THIS MORNING. THE GFS-BASED EXTRATROPICAL STORM SURGE DATA SUGGESTS TIDES WILL FALL JUST SHORT OF COASTAL FLOOD ADVISORY CRITERIA...BUT GIVEN THE STRENGTH OF THE ONSHORE FLOW NOTED ALONG THE LOWER SOUTH CAROLINA COAST SUSPECT THIS MAY BE JUST ENOUGH TO BRING TIDE LEVELS NEAR 7.0 FT MLLW IN THE CHARLESTON HARBOR. WILL ISSUE A COASTAL FLOOD ADVISORY FROM 8 AM UNTIL NOON FOR ALL OF THE SOUTH CAROLINA COASTAL ZONES. ATTM WE BELIEVE TIDES WILL REMAIN BELOW ADVISORY THRESHOLDS ALONG THE NORTH GEORGIA COAST. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR SCZ048>051. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM EST TUESDAY FOR AMZ350-352. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS AFTERNOON FOR AMZ354. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM EST THURSDAY FOR AMZ374. && $$ ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1014 AM CST MON DEC 15 2008 .DISCUSSION... ISSUED 1014 AM CST MON DEC 15 2008 ZONES/GRIDS WERE UPDATED AGAIN RECENTLY TO END THE WINTER WEATHER ADVISORY IN THE SOUTHEAST...AS WELL AS LOWER HIGH TEMPERATURES A BIT. LATEST SURFACE MAP SHOWS TEMPERATURES REMAINING FAIRLY STEADY ACROSS MUCH OF THE CWA THIS MORNING. AREAS OF LIGHT SNOW AND FLURRIES WERE MAINLY SOUTH OF I-70...STREAMING NORTHEAST OUT OF SOUTHEAST MISSOURI. LATEST RUC GUIDANCE AND MET MOS GUIDANCE SHOWING TEMPERATURES GOING NOWHERE FAST TODAY...MAYBE ONLY A COUPLE DEGREES. NEWLY ARRIVED GFS MOS TOO WARM RIGHT OFF THE BAT AND WAS DISCOUNTED. KEPT SMALL MENTION OF LIGHT SNOW ACROSS THE SOUTHEAST CWA...ALTHOUGH IT SHOULD GENERALLY BE TRACE AMOUNTS. GEELHART && .AVIATION... ISSUED 515 AM CST MON DEC 15 2008 PRECIPITATION FROM DEPARTING WINTER STORM HAS ENDED OR WILL END SHORTLY ACROSS THE CENTRAL ILLINOIS TERMINALS. VFR CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE 12Z TAF PERIOD ONCE LINGERING SNOWS END AND ASSOCIATED MVFR CIGS DISSIPATE LATER THIS MORNING. GUSTY NORTHWEST WINDS EXPECTED FOR MUCH OF TODAY BEHIND THE DEPARTING SYSTEM...BUT WILL DIMINISH AND EVENTUALLY BECOME VARIABLE LATER TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. BAK && .PREV DISCUSSION... ISSUED 343 AM CST MON DEC 15 2008 WINTRY PRECIP HAS MADE IT THROUGH THE NWRN HALF OF THE FORECAST AREA THIS MORNING. CLEARING IS MOVING IN RATHER QUICKLY AS COLD AIR RUSHES IN BEHIND THE FRONT. FREEZING RAIN AND SLEET AND SNOW IS STILL OCCURRING IN THE SE WHERE THE FRONT HAS FINALLY MOVED THROUGH IN THE EARLY MORNING HOURS. DRASTIC TEMPERATURE DROPS FROM THE LOW 50S TO THE SINGLE DIGITS IN LESS THAN 12 HOURS. WINTER WX ADVISORY IN THE WRN HALF OF THE FA IS GOING TO BE DROPPED AT FORECAST ISSUANCE AS PRECIP IS ENDING. MANY ISSUES FOR THIS FORECAST RUN...NEXT SYSTEM FOR TUESDAY WITH A PRECIP TYPE PROBLEM...AND THE SAME FOR THURSDAY. TIMING CONSISTENCY IN THE MODELS FOR THE THURSDAY SYSTEM IS NON EXISTENT. CURRENT FORECAST IS A CONSERVATIVE BLEND OF THE NAM/WRF AND THE ECMWF. SHORT TERM...TODAY AND TONIGHT... BITTERLY COLD DAY...WITH EASTERN AREAS SEEING THEIR HIGH TEMP THIS MORNING. PRECIP MOVING ACROSS CENTRAL ILLINOIS QUICKLY...SHOULD BECOME ALL SNOW BY MID DAY. ACCUMULATIONS WILL BE NEGLIGIBLE WITH LESS THAN A HALF AN INCH IN MOST AREAS. HOWEVER THOUGH MODELS DO LINGER PRECIP UNTIL 00Z SOUTH OF INTERSTATE 72....ENSEMBLES HINTING AT SOME LIFT A BIT FURTHER NORTH IN THE OVERNIGHT HOURS...ENHANCING A CHANCE FOR PRECIP A BIT FURTHER BACK THAN THE OPERATIONAL MODELS. HAVE PUT IN CHANCE POPS FOR THE OVERNIGHT HOURS SOUTH OF INTERSTATE 70. THIS WILL BE ALL SNOW...AND ACCUMULATIONS SHOULD GENERALLY BE LESS THAN A HALF OF AN INCH. LONG TERM...TUESDAY THROUGH FRIDAY... REST OF THE WEEK A BIT OF A MESS AS WELL. TUESDAY SYSTEM SHOWING UP A BIT EARLIER IN THE FORECAST. MODELS SHIFTING THE WAVE SOMEWHAT TO THE NORTH...AND KEEPING A LOT OF THE HEAVIER SNOW WELL TO THE NORTH OF THE FORECAST AREA. CURRENT TOTALS IN THE FORECAST AND BY HPC ARE NOT QUITE REACHING INTO ADVISORY CRITERIA. EVEN THOUGH HEADLINES ARE WARRANTED TO THE NORTH...WILL WITHHOLD ANY HEADLINE AS MODELS ARE STILL TRENDING HEAVIER SNOW AWAY FROM ILX. THAT BEING SAID...AS THE WARMER AIR ALSO SHIFTS FURTHER NORTH...SIGNALS ARE SHOWING UP FOR ANOTHER GLAZING OF ICE FOR CENTRAL ILLINOIS. WHAT MAY START AS SNOW TUESDAY...MAY END UP WITH SOME FREEZING DRIZZLE TUESDAY NIGHT AS ICE CRYSTALS DISAPPEAR FROM THE COLUMN. BRIEF RESPITE ON WEDNESDAY UNTIL ANOTHER WAVE MOVES UP FROM THE DESERT SW INTO THE MIDWEST. MAJOR DIFFERENCES WITH THIS SYSTEM AS THE GFS FAR MORE EXPLOSIVE WITH THE DEVELOPMENT...WIDESPREAD AND MORE INTENSE. NAM HOLDS BACK BY AT LEAST 6 HOURS. GFS IS ALSO SOMEWHAT WARMER...AND THE PRECIP TYPE TROUBLE ZONE IN THE MIDWEST IS PARKED RIGHT OVER CENTRAL ILLINOIS...RESULTING IN A WINTRY MIX YET AGAIN. AT THIS POINT...THERE ARE VERY FEW DAYS IN THE FORECAST WITHOUT A CHANCE FOR PRECIP WITH SEVERAL WAVES MOVING OUT OF THE SOUTHWEST ACROSS THE REGION COLLIDING WITH VERY COLD SURFACE AIR DRAINING INTO THE MIDWEST FROM CENTRAL CANADA. FORECAST VERY DYNAMIC WITH MANY ADJUSTMENTS LIKELY THROUGH THE NEXT COUPLE OF DAYS. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1012 AM CST MON DEC 15 2008 .UPDATE... WINTER STORM WARNING CONTINUES ALONG THE SOUTH SHORE OF LAKE SUPERIOR WHERE LIGHT SNOW AND STRONG WINDS PERSIST. AROUND AN INCH OF NEW SNOW CAN BE EXPECTED IN THIS AREA THIS MORNING...BUT THE MAIN THREAT IS LOW TO ZERO VISIBILITY ALONG AND NORTH OF HIGHWAY 2. SFC STATIONS AT ASX/IWD REPORT RESTRICTED VISIBILITIES OF 2 SM OR LESS. HWY 2 WEST OF ASHLAND REMAINS CLOSED ATTM...BUT TRAFFIC IS BEING DETOURED. ANTICIPATE WILL ALLOW THE WARNING TO EXPIRE AT NOON...WHERE A WIND CHILL ADVISORY WILL TAKES ITS PLACE. CANCELED THE WINTER STORM WARNING FOR NE MN GO...AND HAD A WIND CHILL ADVISORY GO RIGHT INTO EFFECT. UPGRADED THE WIND CHILL ADVISORY TO A WIND CHILL WARNING FOR MOST AREAS OVERNIGHT FROM 6 PM THIS EVENING THROUGH 9 AM TUES MORNING. ATTM...KEPT THE SRN TIER OF ZONES /BRD TO HYR AND PBH/ AS ADVISORY OVERNIGHT SINCE GRADIENT SPREADS SWRD AND WINDS WILL BE LIGHTER BUT MAY NEED TO UPGRADE THIS AREA TO WIND CHILL WARNING IF WINDS LOOK TO REMAIN ABOVE THRESHOLD. && .PREV DISCUSSION... /ISSUED 351 AM CST MON DEC 15 2008/ ..WINTER STORM WINDS DOWN WITH LIGHT SNOW... ....EXCESSIVE COLD EXPECTED THIS WEEK... .....WIND CHILL ADVISORY TODAY AND TONIGHT... DISCUSSION...SFC LOW HAS MOVED INTO SRN ONTARIO WITH CWA LEFT UNDER MASSIVE AREA OF ARCTIC AIR AND GUSTY WINDS. A SECONDARY SHORTWAVE EMBEDDED IN THE MID LVL TROF HAS EJECTED NORTHEAST THIS MORNING SPREADING ANOTHER ROUND OF LIGHT/MDT SNOW FROM THE TWIN PORTS INTO THE ARROWHEAD. IT APPEARS ONE MORE SHORTWAVE IS PUSHING ACROSS ERN SD INTO SW MN ACCORDING TO LATEST 11U/3.9U IMAGERY. LATEST RUC80 FCST OF THIS FEATURE SWINGS IT ACROSS CWA BY 18Z. WILL LET WSW CONTINUE AS LIGHT SNOW IS EXPECTED TO LINGER WITH GUSTY WINDS/BLOWING SNOW. AFTER WSW EXPIRES...WIND CHILL ADVISORY WILL BE IN EFFECT THROUGH 15Z TUESDAY. WIND CHILL VALUES ALREADY AT 30 TO 35 BELOW ACROSS MOST OF MN ZONES AND 15 TO 25 BELOW ACROSS WISC. MAIN STORY WILL BE COLD AIR AND WIND CHILLS THROUGH THE WEEK. MAY NEED TO UPGRADE WCA TO WIND CHILL WARNING TONIGHT ACROSS RANGE/ARROWHEAD. MAV GUIDANCE HAS BEEN TOO WARM SO FAR WITH THIS OUTBREAK AND THIS TYPICALLY IS THE CASE. MET NUMBERS A BIT BETTER. SUSPECT CLEARING WILL OCCUR TONIGHT HOWEVER RADIATIONAL COOLING CONDITIONS ARE NOT OPTIMAL. WINDS IN SFC/925 LAYER STILL BRISK WITH LINGERING PRESS GRADIENT. ALSO...WITH LACK OF SHARP RIDGE AXIS ALOFT MAY SEE SOME CLOUDS SNEAKING IN FROM THE NRN PLAINS. REGARDLESS...STILL EXPECT TONIGH TO BE COLDEST NIGHT OF THIS SEASON SO FAR. ANOTHER ROUND OF LIGHT SNOW WILL SPREAD INTO REGION TUESDAY...PRIMARILY ACROSS SRN HALF OF CWA. GOOD MDL AGREEMENT ON THIS SYSTEM WITH 1 TO 2 INCH SNOWFALL EXPECTED. LONG TERM... MED RANGE MODELS DIVERGE AFTER MID WEEK...WITH GFS BRINGING A STRONG SHORTWAVE AND SFC LOW PRES INTO SRN WI ON THURS. GFS LACKS SUPPORT OF BOTH ECMWF AND GEM GLOBAL HOWEVER...KEEPING THE SYSTEM SOUTH INTO THE OHIO VALLEY DUE TO STRONG ARCTIC HIGH PRES RIDGING INTO WRN ONT. DECIDED TO LEAN TOWARDS THE LATTER SOLUTION...BACKING POPS TO THE LOW CHANCE CATEGORY THUR/THUR NIGHT. BETTER CHANCE OF SNOW BY FRI NIGHT INTO SAT AS FLOW BECOMES SWRLY AHEAD OF BROAD MID LEVEL TROUGH EJECTING OUT OF THE ROCKIES. TEMPERATURES WILL REMAIN MUCH BELOW SEASONAL NORMS THROUGH THE NEXT WEEK WITH ANOTHER POTENTIAL ARCTIC OUTBREAK BY THE WEEKEND. AVIATION... VSBYS WILL REMAIN IN THE IFR RANGE THROUGH THE MORNING DUE TO BLSN AND -SN...WHILE CIGS WILL GENERALLY BE IN THE MVFR RANGE. GUSTY NW WINDS WILL SLOWLY DIMINISH AND BACK THIS AFTERNOON... PUTTING AN END TO THE BLSN...EXCEPT IN KDLH...WHERE WINDS WILL REMAIN GUSTY THROUGH THE EARLY EVENING HOURS. && POINT TEMPS/POPS... DLH -5 -20 -1 -8 / 10 10 20 70 INL -4 -28 -9 -11 / 10 10 10 60 BRD -7 -25 -1 -10 / 10 10 30 60 HYR -4 -20 3 -9 / 10 10 50 70 ASX 1 -18 1 -1 / 70 10 20 70 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS- KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN COOK/LAKESHORE-SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS-KOOCHICHING- NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE- NORTHERN ITASCA-NORTHERN ST. LOUIS-SOUTHERN COOK/LAKESHORE- SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR CROW WING-PINE- SOUTHERN AITKIN-SOUTHERN CASS. WI...WIND CHILL WARNING FROM 6 PM THIS EVENING TO 9 AM CST TUESDAY FOR ASHLAND-BAYFIELD-DOUGLAS-IRON. WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR DOUGLAS. WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR BURNETT-PRICE- SAWYER-WASHBURN. WINTER STORM WARNING UNTIL NOON CST TODAY FOR ASHLAND-BAYFIELD- IRON. WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND- BAYFIELD-IRON. LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121- LSZ148. SMALL CRAFT ADVISORY UNTIL 10 AM CST TUESDAY FOR LSZ146-LSZ147. SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ140- LSZ141-LSZ142-LSZ143. $$ GRANING/GSF mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 533 AM CST MON DEC 15 2008 .AVIATION... /12Z TAF ISSUANCE/ MVFR CEILINGS AND VISIBILITIES IN BLSN TO DIMINISH THIS MORNING AS LOW PRESSURE JUST EAST OF LSUP MOVES NORTHEAST AND ARCTIC HIGH PRESSURE BUILDS IN FROM SD. BRISK NORTHWEST WINDS THROUGH THE DAY WITH NO REAL RELIEF UNTIL LATE IN THE AFTERNOON WEST AND EVENING EAST. THE ARCTIC HIGH WILL BE OVERHEAD TONIGHT WITH VFR CONDITIONS AND LIGHT WINDS. THE TRANQUILITY WILL NOT LAST LONG AS STRONG UPGLIDE AND SATURATION DEVELOPS FROM THE SOUTH ON TUESDAY ALONG WITH MID LEVEL FRONTOGENESIS. ACCUMULATING SNOW DEVELOPING TUESDAY MORNING AT KRWF AND AT THE REST OF THE TAF SITES IN THE AFTERNOON. KRWF...KMSP...KRNH AND KEAU LOOK TO BE IN LINE FOR 2 TO 3 INCHES OF SNOW WITH LESSER AMOUNTS AT KSTC AND KAXN. && .DISCUSSION... /ISSUED 412 AM CST MON DEC 15 2008/ THE FORECAST CHALLENGES CENTER ON WIND CHILLS THE NEXT 18 HOURS...THOUGH ATTENTION IN FUTURE SHIFTS WILL BE TURNING TO TUES/TUES EVE SNOW EVENT AND THEN ANOTHER POSSIBLE ONE FOR THU. LATEST SURFACE ANALYSIS REVEALS 993MB LOW LIFTING NORTHEAST INTO CENTRAL ONTARIO. NEARLY 50MB DIFFERENCE BETWEEN THIS FEATURE AND ARCTIC HIGH PRESSURE CENTER EXPANDING OVER THE CTRL PLAINS. RESULTANT WINDS CONTINUE SUSTAINED AT 25 TO 30 MPH THIS MORNING WITH OCCASIONAL GUSTS TO 40 MPH. TEMPS CONTINUE TO FALL THROUGH THE SINGLE DIGITS BELOW ZERO WITH NEGATIVE DOUBLE DIGITS TO THE START THE DAY IN WEST CTRL MN. WIND CHILLS HAVE BEEN BETWEEN 25 AND 40 BELOW ZERO ACROSS THE AREA FROM EAST TO WEST THROUGH THE EARLY MORNING. OVERALL...AIR TEMPS ARE 35 TO 45 DEGREES COOLER ACROSS THE AREA THAN JUST 24 HOURS AGO! WHAT A CLASSIC EARLY WINTER CYCLONE. CURRENT WINDS SHOULD CONTINUE NEARLY THE SAME IN SPEED AND GUST THROUGH THE MORNING WITH AREA AND UPSTREAM WIND PROFILERS MEASURING 925MB WINDS AT 30 KTS AND RUC SOUNDINGS DIAGNOSING CONTINUED STEEP LOW LEVEL LAPSE RATES. THESE WINDS WILL VERY GRADUALLY EASE THIS AFTN AND WITH THAT THE BLOWING SNOW SHOULD TOO. 1000-850MB COLD AIR ADVECTION ALSO PROGGED TO ACCORDINGLY DIMINISH GRADUALLY. SO TEMPS ARE THOUGHT TO BE NEARLY STEADY THIS MORNING FOLLOWED BY CLIMBING A HANDFUL OF DEGREES THIS AFTN. WIND CHILLS THIS ENTIRE TIME THOUGH SHOULD REMAIN IN ADVISORY CRITERIA WITH WARNING CRITERIA CONTINUING ACROSS THE WEST. SO HAVE EXTENDED HEADLINES. WRN WI LIKELY TO CONTINUE WITH WIND INTO THIS EVE UNDER DEPARTING MSLP GRADIENT SO HAVE ADVISORY GOING TO MIDNIGHT IN THAT AREA. AIR TEMPS WILL BE VERY COLD TONIGHT AS THE ARCTIC HIGH OF 1040MB MAGNITUDE MOVES OVER THE SRN CWA. DIMINISHING WIND SPEEDS IN MN...CLEAR SKIES CWA WIDE...AND FRESH SNOW COVER IN MANY PLACES WILL RESULT IN AN IDEAL SETUP FOR PLUNGING TEMPS BETWEEN 7 PM AND 9 PM. NEGATIVE DOUBLE DIGITS LIKELY TO PREVAIL ACROSS MUCH OF THE MN CWA BY 9 PM. FRESH SNOW COVER EXPECTED TO HAVE A SEVERAL DEGREE IMPACT. RECENT LOCAL CLIMATOLOGICAL RESEARCH WITH A NIGHT AFTER A FRESH SNOW AND THESE SIMILAR SYNOPTIC CONDITIONS WOULD INDICATE NEAR -18F AT MSP. HAVE GONE JUST SLIGHTLY ABOVE THAT WITH SOME CIRRUS/CIRROSTRATUS EXPECTED VERY LATE. AREAS OF WEST CTRL MN WITH DEEP FRESH SNOW ARE EXPECTED TO DROP TO -23 TO -28. RECORD LOW MIN TEMP AT ST CLOUD FOR TUES MORNING IS -21 IN 1963 WHICH WILL BE IN GREAT JEOPARDY. ON THE IMMEDIATE HEALS OF THIS ARCTIC HIGH WILL COME A POTENT MID- LEVEL SHORT WAVE RIDING NORTHEAST WITHIN THE POWERFUL STATIONARY UPPER LEVEL JET TO OUR SOUTH ON TUES AND TUES NIGHT. VORT ADVECTION AND MID-LEVEL WARM AIR ADVECTION IS STRONG AND FOCUSED AHEAD OF THIS. THE 00Z AND 06Z NAM HAVE BEEN A BIT MORE POTENT WITH THIS...BUT BOTH THESE...THE 00Z GFS...AND 21Z SREF FAVOR AT LEAST SRN MN TO WRN WI TO BE UNDER A CORRIDOR OF SNOW DURING TUES AFTN AND EVE. WITH THE SNOW FALLING INTO A VERY COLD AIR MASS...RATIOS ARE LIKELY TO BE AT LEAST 17:1 IF NOT CONSIDERABLY HIGHER. FORECAST SNOWFALL TOTALS OF 2 TO 4 INCHES RIGHT NOW WOULD WARRANT AN ADVISORY AS TIME APPROACHES AND THE IMMEDIATE WIND CHILL CONCERNS END. THIS WILL HAVE TO BE WATCHED CLOSELY...AS FAVORABLE QUADRANT FOR STATIONARY BANDING MAY ENTER THE CWA AND INCREASE THOSE SNOWFALL AMOUNTS FROM ALBERT LEA...TO RED WING...TO EAU CLAIRE. ALSO POSSIBLE THAT ADVISORY AMOUNTS MAY NEED TO BE EXTENDED NORTHWARD TOWARDS THE TWIN CITIES...BUT AT THIS TIME UNCERTAINTIES REMAIN. ONE OF THOSE IS A WAVE ON THE POLAR JET TO OUR NORTH WHICH DOES MOVE IN DURING THE EVE. THE INFLUENCE THIS HAS ON THE SRN SHORT WAVE MAY ENHANCE AMOUNTS FURTHER NORTH DURING THE LATE AFTN AND EVE. HAVE FORECASTED SNOWFALL AMOUNTS RIGHT NOW IN THE ENVELOPE OF MOST CONFIDENCE WHICH CONTINUES TO INCREASE. AFTER THAT...A SYSTEM ON THU IN THE MIDDLE OF THE COUNTRY POTENTIALLY KEEPS OUR ONE SYSTEM-EVERY-36-HOUR PATTERN GOING STRONG. THIS SYSTEM IS THE BULK OF THE ENERGY OF THE NOW CLOSED LOW DROPPING SOUTHWARD OFF THE PACIFIC COAST THIS MORNING. MODELS HANDLE THIS CONSISTENTLY THROUGH THE FIRST 48 HOURS BUT THEN DIVERGE MID-WEEK IN THE RESPONSIVE LEE-CYCLOGENESIS. 00Z GFS WAS AN OUTLIER...BRINGING A LOW ON A VERY INTERESTING PATH FAVORING GOOD SNOW HERE. 00Z ECMWF ON THE OTHER HAND IS THE FURTHEST SOUTH BRINGING THE LOW INTO SRN IL AND GIVING US BASICALLY NOTHING. ENSEMBLE LEANS TOWARDS THE ECMWF WHICH HAS BEEN CONSISTENT AT KEEPING THE MAJORITY OF THE THE PRECIP FROM THIS SYSTEM TO OUR SOUTH. WILL HAVE TO WATCH CLOSELY BUT TOUGH AT THIS POINT TO GET A GOOD HANDLE ON THE GUIDANCE WITH THAT SYSTEM. HAVE GENERALLY KEPT THINGS AS IS WITH THE FORECAST DURING THU. OVERALL...BELOW NORMAL TEMPS TO PREVAIL THROUGH THE WEEK WITH ANOTHER COLD SHOT OF A POTENTIAL SIMILAR MAGNITUDE AS THIS CURRENT ONE BECOMING MORE LIKELY NEXT WEEKEND. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO- DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI- KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD- MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD- RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS- SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ANOKA- BENTON-BLUE EARTH-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN- GOODHUE-HENNEPIN-ISANTI-KANABEC-LE SUEUR-MCLEOD-MEEKER- MILLE LACS-MORRISON-NICOLLET-RAMSEY-RICE-SCOTT-SHERBURNE- SIBLEY-STEARNS-STEELE-WASECA-WASHINGTON-WRIGHT. WIND CHILL WARNING UNTIL 6 PM CST THIS AFTERNOON FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MARTIN-POPE- REDWOOD-RENVILLE-STEVENS-SWIFT-TODD-WATONWAN-YELLOW MEDICINE. WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BARRON- CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. && $$ RAH/MTF mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 350 AM PST MON DEC 15 2008 .SYNOPSIS...A VERY COLD STORM SYSTEM WILL AFFECT THE AREA THROUGH THE MIDDLE OF THE WEEK...WITH TEMPERATURES WELL BELOW NORMAL AND CHANCES FOR SNOW IN MUCH OF THE MOJAVE DESERT. A DRYING TREND IS EXPECTED FOR THE END OF THE WEEK...BUT CHILLY TEMPERATURES WILL PERSIST. && .SHORT TERM...SATELLITE AND AREA RADAR LOOPS SHOW BROAD ASCENT OCCURRING OVER MOST OF OUR CWFA...WITH CLOUDS LOWERING AND THICKENING AND RADAR RETURNS SLOWLY INCREASING. THIS IS IN EXCELLENT ALIGNMENT WITH THE RUC MODEL FORECASTS...WHICH SUGGESTED PRECIP BREAKING OUT IN THE LAS VEGAS VALLEY BETWEEN 3 AM AND 5 AM. SURFACE OBS SHOW SNOW OCCURRING AT KBIH AND KDRA AS OF 3 AM. USING AN APPROXIMATION FROM DRY BULB AND DEWPOINT...3 AM WET BULB TEMPERATURES WERE ABOUT 31F AT KLAS...34F AT KDAG...35F AT KNXP...AND 27F AT KIGM. THIS SUPPORTS THE CONFIGURATION OF THE WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES...AND WILL MAKE NO CHANGES AT THIS TIME. THE NAM12 SUGGESTS A DRY PERIOD TONIGHT AND TUESDAY BETWEEN IMPULSES...BUT THE GFS HOLDS ON TO MORE MOISTURE. TRIED TO BLEND THE TWO SOLUTIONS...SHOWING A SLIGHT DOWNWARD TREND IN POPS TONIGHT AND TOMORROW...BUT NOT NEARLY AS DRY AS THE NAM12. WILL WORRY MORE ABOUT LATER TIME PERIODS AFTER THIS FIRST STORM IS OVER. .LONG TERM...THURSDAY AND FRIDAY WILL SEE THE AREA IN DRYING NORTHWEST TO WEST FLOW IN THE WAKE OF THE WEDNESDAY SYSTEM. NEXT SYSTEM TO AFFECT THE CWA WILL BE A FRONT DROPPING SOUTH INTO AREA SATURDAY. SO FAR MODELS DEPICT THIS AS A PRIMARILY DRY EVENT WITH LITTLE MOISTURE ASSOCIATED WITH THE SURFACE FRONT. MAIN ELEMENTS TO WATCH ARE THE WINDS AND TEMPERATURES. DID RAISE WIND SPEEDS IN GRIDDED DATABASE BUT NOT TO THE BREEZY LEVEL OR HIGHER WITH THE EXCEPTION BEING THE LOWER COLORADO RIVER VALLEY WHERE BREEZY SHOWS UP IN TEXT. OTHER ACTION TAKEN WAS TO LOWER TEMPERATURES 5 TO 7 DEGREES ON AVERAGE SATURDAY AND SUNDAY AS THE SATURDAY FRONT IS DEPICTED VERY WELL IN THE THICKNESS RIBBON AND GUIDANCE POINTS THAT WAY AS WELL. LOOKING FURTHER MODELS HAVE ANOTHER STRONG AND MOIST LOW DROPPING IN FROM THE NORTHWEST...IT PORTENTS TO BE VERY ACTIVE THE TWO DAYS PRIOR TO CHRISTMAS. && .AVIATION...FOR MCCARRAN...CLOUD BASES WILL CONTINUE TO LOWER THIS MORNING BEFORE THE BEGINNING OF PRECIPITATION. CONFIDENCE IN THE TIMING OF EVENTS IN THE 12Z TAF IS LOW AS LOW CIGS/VSBY/SNOW IS A NOT A COMMON EVENT. A 13 TO 15Z ONSET OF PRECIPITATION IS STILL LIKELY WITH IT BEGINNING AS A MIX OF RAIN AND SNOW. BY LATE MORNING IT SHOULD BE ALL SNOW AND THEN TURN BACK TO A RAIN AND SNOW MIX IN THE LATE AFTERNOON ONWARDS. ACCUMULATIONS OF UP TO AN INCH IS BRIEFLY POSSIBLE BUT EXPECT WARM GROUND TEMPERATURES TO QUICKLY MELT THE SNOW. THE 12Z TAF REPRESENTS BEST ESTIMATE OF HOW LOW CIGS AND VSBY WILL DROP IN THE SNOW. STILL LOOK FOR QUICK IMPROVEMENT IN CONDITIONS AROUND AND AFTER 03Z THIS EVENING. THE NEXT SYSTEM BRINGING THE WEATHER TO THE AREA WILL MOVE THROUGH WEDNESDAY TO BRING ANOTHER SHOT OF SNOW...LOW CIGS AND VSBY THEN. THE BRUNT OF THE WORST CONDITIONS SHOULD OCCUR SOUTH AND EAST OF KLAS IN ARIZONA. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...CEILINGS ARE LOWERING THIS MORNING FROM WEST TO EAST AS MOIST AIR FLOWS IN FROM THE WEST OVER COLD AIR ENTRENCHED OVER THE REGION. EXPECT VERY WIDESPREAD RAIN AND SNOW TODAY AND THE ATTENDANT LOW CIGS AND VSBY. MOST AREAS WILL SEE IFR CONDITIONS FOR A CONSIDERABLE TIME TODAY. CONDITIONS WILL CLEAR FROM THE WEST THIS EVENING WITH PRECIPITATION OVER WITH IN ALL AREAS BY MIDNIGHT. ANOTHER STRONG STORM IS EXPECTED TO MOVE THROUGH THE AREA WEDNESDAY AND AGAIN BRING WIDESPREAD RAIN...SNOW AND LOW CIGS AND VSBY. && .CLIMATE...WITH SNOW IN THE FORECAST FOR LAS VEGAS HERE ARE SOME STATISTICS ON SNOW. DATA ARE FOR THE OFFICIAL SNOWFALL REPORTING SITE FOR LAS VEGAS...WHICH WAS AT MCCARRAN INTERNATIONAL AIRPORT FROM 1937 THROUGH JANUARY 31 1996...AND THEN 2 MILES SOUTHWEST AT THE NWS OFFICE ON DEAN MARTIN ROAD SINCE FEBRUARY 1 1996. THE LAST TIME SNOW OFFICIALLY FELL IN LAS VEGAS WAS ON DECEMBER 22ND 2006 WHEN A TRACE OF SNOW WAS MIXED IN WITH RAIN. THE LAST TIME MEASURABLE SNOW OFFICIALLY FELL IN LAS VEGAS WAS ON DECEMBER 30TH 2003 WHEN 1.3 INCHES FELL. THE RECORD SNOWFALL FOR THE MONTH OF DECEMBER IN LAS VEGAS WAS IN 1967...WHEN 2.0 INCHES FELL. COINCIDENTALLY...THAT SNOW ALSO FELL ON DECEMBER 15TH. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...WINTER STORM WARNING UNTIL 10 PM PST TODAY FOR NVZ018-019-022. WINTER WEATHER ADVISORY UNTIL 4 PM PST TODAY FOR NVZ015>017-020. AZ...WINTER STORM WARNING FROM 8 AM TODAY TO 5 AM MST TUESDAY FOR AZZ001-003. CA...WINTER STORM WARNING UNTIL 10 PM PST TODAY FOR CAZ524. WINTER WEATHER ADVISORY UNTIL 4 PM PST TODAY FOR CAZ519. && $$ MORGAN/JACQUES HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 854 AM EST MON DEC 15 2008 .SYNOPSIS... A VIGOROUS COLD FRONT...WILL CROSS THE REGION THIS MORNING. AS COLD AIR SPILLS BEHIND IT...A WINTRY MIX OF PRECIPITATION WILL BE POSSIBLE TODAY AND THE RAPID DROP IN TEMPERATURES MAY LEAD TO SLICK CONDITIONS. THE FRONT WILL STALL SOUTH OF THE OHIO VALLEY. AN UPPER LEVEL DISTURBANCE WILL BRING A SHOOT OR PRECIPITATION TONIGHT...BEFORE A WAVE OF LOW PRESSURE RIDES UP THE FRONT TUESDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WELL DEFINED COLD FRONT ON KILN RADAR PLOWING THRU FCST AREA. FRONT HAS PASSED THRU ILN AND CMH METRO WITHIN THE LAST THIRTY MINS. TEMPS FALLS ARE THEN FAST AND FURIOUS IN THE WAKE OF THE FROPA...AND THAT IS REQUIRING SOME CHANGES TO FCST FOR TODAY. RUC MODEL SEEMS TO HAVE A REALLY NICE HANDLE ON THE TEMP FALLS AND HAVE UTILIZED ITS SOLN FOR TEMPS PRIMARILY INTO THE AFTN HOURS. ANALYSIS OF OBS TO OUR WEST INDCG THAT IT IS TAKING ABOUT THREE HOURS OR SO FRO TEMPS TO FALL TO THE FREEZING LEVEL AFTER FROPA. HAVE THEREFORE...GONE MUCH MORE AGGRESSIVE WITH TEMP FALLS FOR THE REST OF THE DAY...WITH LOCATIONS FALLING INTO THE 20S TO L30S (MAYBE EVEN LOWER THAN THAT). MORE SIGNIFICANT ISSUE TO CONTEND WITH IS IMPACT TEMP FALLS WILL HAVE ACRS THE REGION. PCPN CHANGING FROM -RA TO -FZRA/PL AND EVENTUALLY SOME VERY LIGHT SNOW AS COLDER AIR RUSHES INTO REGION. HOWEVER...PCPN IS LIGHT ENUF THAT IT IS NOT LIKELY TO CAUSE SIGNIFICANT PROBLEMS AS IT CHANGES TO -FZRA/PL/-SHSN. OF MUCH GREATER CONCERN IS THE POTENTIAL FOR A FLASH FREEZE ON ROADS/EXPOSED SURFACES DUE TO THE SIGNIFICANT NATURE OF THE TEMP FALLS. ESSENTIALLY...THE TEMPERATURE WILL FALL SO QUICKLY THAT WATER ON THE ROADS AND EXPOSED SURFACES STAND A GREATER CHANCE TO FREEZE RAPIDLY CAUSING POTENTIAL FOR BLACK ICE AND SLICK ROADS. INTEND TO HANDLE THIS WITH A WINTER WX ADVISORY AND EXTEND IT OUT FOR THE ENTIRE AREA...BEGINNING IMMEDIATELY ACRS NW 1/2 FCST AREA AND BY 16Z FURTHER TO THE SOUTHEAST. IN AN EFFORT TO KEEP THINGS SIMPLE AND NOT CONFUSE THE PUBLIC...FELT BEST COURSE OF ACTION WAS TO MERGE THE ADVISORIES WE HAD UP FOR THIS MRNG ACRS WEST CNTRL OH AND TONIGHT ALONG AND SOUTH OF I-71 INTO ONE PRODUCT WITH TWO SEGMENTS. THE ADVISORY FOR WINTRY PCPN TONIGHT WILL NOW BEGIN AT 16Z TO ACCOUNT FOR POTENTIAL FLASH FREEZING CONDITIONS THIS AFTN. THE ADVISORY WILL THEN CONTINUE IN ITS PREV STATE TONIGHT FOR THE EXPECTED WINTRY PCPN. THE REMAINDER OF THE FCST AREA TO THE NORTHWEST OF I-71 WILL HAVE AN ADVISORY FOR FLASH FREEZE POTENTIAL NOW THRU 22Z. WILL BE ISSUING UPDATED ADVISORY AND HWO MOMENTARILY...ALONG WITH A NEW ZONE FCST. WILL REEVALUATE THIS LATER THIS MRNG AND INTO THE AFTN FOR ANY POTENTIAL UPDATES. MORE THAN LIKELY THOUGH...THIS WILL NOT BE THE ONLY FCST UPDATE IN A RAPIDLY EVOLVING WX SCENARIO. ZONE AND GRID UPDATES OUT SHORTLY. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... MODELS EJECT A H/5 VORT OUT TONIGHT. THIS CAUSES A DEFORMATION BEND TO DEVELOP ACRS THE SRN PORTION OF THE FA TONIGHT...RUNNING ALONG A SDF-CVG-CHILLICOTHE LINE.THICKNESSES SHOULD COLD ENUF FOR SNOW...EXCEPT IN KY...WHERE SOME PL IS POSSIBLE. MODELS ARE SHOWING SLIGHT DIFFERENCES...MAINLY IN THE AMOUNT OF QPF PRODUCED. THE NAM IS DRIER...ESPECIALLY IN THE NW COUNTIES..WHILE THE NGM AND ECMWF ARE MUCH WETTER. THE GFS LOOKS TO BE A NICE COMPROMISE...SO LEANED TOWARDS IS SNOW AND QPF. WENT WITH A 2-4 INCH SNOW SWATH SURROUNDED BY A 1-3. WENT A WINTER WX ADVISORY FOR THE SRN 2/3 OF FA. THAT ENERGY SLIDES NE OF THE REGION FOR TUE. THERE IS STILL SOME LINGERING OVERRUNNING LIFT...ESPECIALLY IN THE S ON TUE...BUT ONLY LIGHT PCPN AMOUNT S EXPECTED. THEN NEXT AND STRONGER H5 VORT KICKS OUT OF THE MS VALLEY TUE NIGHT...CAUSING A SFC LOW TO DEVELOP. WITH ARCTIC AIR IN PLACE...SFC TEMPS WILL BE BELOW FREEZING. HOWEVER H8 TEMPS WILL RISE QUICKLY ABOVE 0 C AND WITH GOOD ISENTROPIC LIFT. NAM AND GFS ARE SIMILAR WITH THE OVERALL FEATURES...WITH THE GFS A LITTLE DEEPER WITH THE LOW. LEANED TOWARDS THE GFS...SO LOOKS LIKE A PERIOD OF FZRA UNTIL SFC TEMPS WARM ABOVE FREEZING. THE NW WILL PROBABLY SEE SOME SNOW AT THE ONSET...SINCE THE COLD AIR IS DEEPER UP THERE. THERE IS ENUF THREAT TO ISSUE A WINTER STORM WATCH FOR TUE NGT. LOW PASSES TO THE E LATE TUE NGT INTO WED. LOOKS LIKE THERE WILL BE SOME LINGERING PCPN EARLY WED....BUT IT SHOULD END BY NOON. GFS TRIES TO DEVELOP ANOTHER LOW IN THE PLAINS WITH A WRMFNT IN THE OH VLY. THE OLD ECMWF WASNT AS STRONG...SO DISCOUNT THE 00Z GFS FOR WED NGT. GENERALLY WENT CLOSE TO MAV...SINCE LEANED TOWARDS THE GFS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ACTIVE WEATHER PATTERN THROUGH THE EXTENDED FORECAST PERIOD. HAVE TRENDED THE FORECAST SOLN CLOSER TO OPERATIONAL ECMWF WITH A HIGH DEGREE OF UNCERTAINTY REGARDING EXACT TIMING OF INDIVIDUAL WX SYSTEMS. UPPER LEVEL FLOW BACKS WITH A DEEPENING LOW EJECTING NE FROM THE CENTRAL PLAINS ON THURSDAY INTO THE OHIO VALLEY THURSDAY NIGHT. MODEL DIFFERENCES ON THE TIMING AND LOCATION OF THIS LOW. THE GFS IS QUICKER AND FURTHER N WITH THE LOW. HAVE FOLLOWED THE COLDER AND SLOWER ECMWF SOLN BUT OPTED FOR A LTL QUICKER RETURN OF MOISTURE. HAVE SPREAD OVERRUNNING PRECIP BACK NORTH LATE WED NIGHT INTO THURSDAY. THIS PRECIP WL LIKELY BEGIN AS A WINTRY MIX BEFORE CHANGING OVER TO RAIN AS WARMER AIR ADVECTS IN LATE THUR NIGHT AND EARLY FRI PRIOR TO FRONTAL PASSAGE. SURFACE HI TO PROVIDE DRY WEATHER FRIDAY NIGHT INTO SATURDAY. ARCTIC FRONT LOOKS TO PASS THRU LATE SATURDAY WITH COLD TEMPS AND DRY WX EXPECTED NEXT SUNDAY. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... WIDESPREAD RAIN AHEAD OF AND BEHIND FRONTAL PASSAGE WILL BRING VSBYS TO MVFR CONDITIONS AT TIMES THIS MORNING. FROPA WILL BE ON THE WESTERN TAF SITES BORDER AT 12Z AND WORK QUICKLY EAST...THROUGH CMH AND ILN BY 1330Z THIS MORNING. RAIN WILL HANG ON FOR A BIT BEHIND FROPA BUT SFC TEMPS WILL DROP TO BELOW FREEZING FOR A FEW HOURS BEFORE PRECIP ENDS. CIGS WILL DROP TO THE MVFR CATEGORY THIS MORNING AND AFTERNOON BUT SEE A FEW UPWARD PEEKS WHERE THE LOW SC DECK IS OCCASIONALLY SCT UNDER A BKN 6-10KFT DECK. WEST WIND SHIFT WILL ANNOTATE FROPA THIS MORNING. BY EVENING...AN UPPER VORT WILL WRING OUT SOME SNOW ALONG AND ESP SE OF I-71 CORRIDOR. AM NOT ENTIRELY CERTAIN WHERE THE BACK EDGE OF THIS SNOW IS BUT ENOUGH DRY AIR AT THE MID LEVELS COULD ALLOW LOWER SC DECK FROM 1-2KFT TO BREAK UP AT TIMES OVERNIGHT...ESP TO THE NW. OUTLOOK...MVFR CIGS/VSBYS POSSIBLE THROUGH WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR OHZ026-034-035-042>046-051>053-060-061. WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR OHZ026-034-035-042>046-051>056-060>065-070>074- 077>082-088. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR OHZ054>056- 062>065-070>074-077>082-088. KY...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR KYZ089>100. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR INZ050-058-059-066. WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR INZ050-058-059-066-073>075-080. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR INZ073>075- 080. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...SITES LONG TERM...AR AVIATION...FRANKS oh AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE TALLAHASSEE FL 300 PM EST MON DEC 15 2008 .SYNOPSIS... 20Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING A SPLIT UPPER LEVEL PATTERN ACROSS THE NATION. NORTHERN STREAM FLOW HAS DUG A SIGNIFICANT LONGWAVE TROUGH ACROSS MUCH OF THE WEST AND INTO THE CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST. TREMENDOUS COLD AIR HAS SPILLED OUT OF SOUTHERN CANADA INTO PORTIONS OF THE NORTHERN/CENTRAL U.S. WITH THIS TROUGH. AIR TEMPS FROM MONTANA TO COLORADO EASTWARD TO THE MIDDLE MS VALLEY AND NORTH TO THE WESTERN GREAT LAKES WERE WELL BELOW ZERO THIS MORNING WITH MANY SPOTS 15 TO 25 DEGREES INTO THE NEGATIVE. CURRENT AFTERNOON TEMPS ARE NOT MUCH BETTER WITH MANY LOCATIONS FAILING TO GET ABOVE ZERO (BRRRR!). CONDITIONS ARE RADICALLY DIFFERENT FURTHER TO THE SOUTHEAST WITH LONGWAVE RIDGING BUILDING OVER THE GULF COAST AND EVENTUALLY THE REST OF THE SOUTHEAST BY MIDWEEK. SOUTHERN STREAM FLOW RUNNING NORTHEAST FROM MEXICO AND ACROSS AL/GA CONTINUES TO PROVIDE ABUNDANT MID/HIGH LEVEL MOISTURE. AT THE SURFACE...FORECAST AREA REMAINS IN A MOIST SOUTHEAST FLOW PATTERN BETWEEN HIGH PRESSURE OFF THE MID-ATLANTIC COAST AND A COLD FRONT MOVING SOUTHEAST OUT OF THE TENNESSEE AND SOUTHERN MS VALLEYS. THIS COLD FRONT IS THE DIVIDE BETWEEN THE BALMY AIRMASS IN PLACE ALONG THE NORTHEAST GULF COAST AND THE FRIGID ARCTIC AIR TO THE NORTHWEST. HARD TO BELIEVE WITH OUR CURRENT TEMPS IN THE LOWER TO MIDDLE 70S THAT READINGS ARE DROPPING THROUGH THE LOWER 30S AS CLOSE AS NORTHERN MISSISSIPPI. .SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)... TONIGHT...COLD FRONT WILL BE DROPPING INTO SOUTHERN MS/CENTRAL AL DURING THE EVENING HOURS. ALTHOUGH IT IS A BIT SCARY TO SEE THIS FRONT AND THE LARGE TEMPERATURE DROPS IN ITS WAKE STILL CHARGING SOUTHEAST...IT SHOULD NEVER REACH OUR AREA. STRONG RIDGING TO OUR SOUTH IS UNANIMOUSLY PROGGED BY GUIDANCE TO STALL THE FRONT IN ITS TRACKS LATER THIS EVENING AND OVERNIGHT JUST OUTSIDE OF OUR FAR WESTERN AND NW ZONES. FORCED ASCENT AHEAD OF THE BOUNDARY ALONG THE NOSE OF A STRENGTHENING LOW LEVEL THETA-E RIDGE WILL COMBINE WITH OCCASIONAL SYNOPTIC SUPPORT FROM A SERIES OF PASSING SOUTHERN STREAM IMPULSES TO PROVIDE FOCUS FOR A SCATTERING OF SHOWERS ACROSS AL INTO WEST-CENTRAL GA. AS THE FRONT EDGES CLOSER THROUGH THE EVENING THE CHANCE WILL REMAIN FOR A FEW SCATTERED SHOWERS TO REACH OUR WESTERN AND NORTHWESTERN ZONES. MAINLY LOOKING AT CHANCE RANGE POPS NORTH AND WEST OF A LINE FROM AROUND ALBANY TO PANAMA CITY. HOWEVER... RAINFALL ACCUMULATIONS WITH THE SHOWERS SHOULD BE ON THE LIGHT SIDE. FURTHER SOUTHEAST ACROSS THE REMAINDER OF THE FORECAST AREA ONLY LOOKING FOR A FEW ISOLATED SPRINKLES WITH A VERY LOW CHANCE OF MEASURABLE RAINFALL. VERY WARM NIGHT FOR MID-DECEMBER IN STORE WITH MIDDLE AND UPPER 50S COMMON. DUE TO THE EAST TO SOUTHEAST FLOW OFF THE COASTAL WATERS...TEMPS WILL HAVE A HARD TIME DROPPING OUT OF THE LOWER 60S ALONG THE COAST FROM WAKULLA COUNTY WESTWARD. DIFFICULT FORECAST FOR FOG OVERNIGHT. WILL LEAVE MENTION OF PATCHY TO AREAS OF FOG IN THE GRIDS HOWEVER...IT SHOULD BE NOTED THAT THE LATEST SREF ENSEMBLES ARE AGAINST ANYTHING WIDESPREAD. NOT MUCH CHANGE IN PATTERN THROUGH MOST OF THE DAYLIGHT HOURS OF TUESDAY. FRONTAL BOUNDARY IS PROGGED TO REMAINS STALLED JUST TO OUR NORTHWEST. SHOULD CONTINUE TO SEE THE CHANCE FOR A FEW SCATTERED SHOWERS ACROSS THE FL PANHANDLE AND INTO SOUTHEAST AL/SOUTHWEST GA. AGAIN MAINLY LOOKING AT AN AREA WEST OF A LINE FROM ALBANY TO PANAMA CITY FOR THESE SHOWERS. RAIN CHANCES SHOULD THEN BEGIN TO DIMINISH AFTER THE MIDDLE AFTERNOON HOURS AS THE BOUNDARY BEGINS EDGING SLOWLY BACK NORTH LATE IN THE DAY TAKING THE BEST WARM AIR/MOISTURE ADVECTION WITH IT. EXPECT THAT AS THE FRONT BEGINS TO LIFT NORTH WE SHOULD SEE SKIES BECOME A MIX OF SUN AND CLOUDS FOR THE AFTERNOON HOURS. WITH 850MB TEMPS BETWEEN 12C AND 13C REGION-WIDE WILL BE EXPECTING TEMPS TO SOAR INTO THE MIDDLE AND PERHAPS UPPER 70S. WITH A WEAK PRESSURE GRADIENT IN PLACE BY AFTERNOON WOULD NOT EVEN BE SURPRISED TO SEE A FEEBLE SEA-BREEZE CIRCULATION DEVELOP. IF IT DOES OCCUR THEN TEMPS ALONG THE IMMEDIATE COAST MAY BE HELD DOWN MORE TOWARD 70 FOR THE MIDDLE AND LATE AFTERNOON HOURS. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT ARE SHAPING UP TO BE QUIET AND UNSEASONABLY WARM ACROSS THE FORECAST AREA AS THE WEATHER PATTERN TAKES ON AN APPEARANCE MORE SUMMER-LIKE THAN ONE APPROACHING THE FIRST DAYS OF WINTER. STRONG PIECE OF MID/UPPER LEVEL ENERGY WILL BE DIGGING SOUTH ALONG THE CALIFORNIA COAST AMPLIFYING THE WESTERN U.S. TROUGH. IN RESPONSE WILL SEE THE RIDGE IN PLACE ACROSS THE GULF OF MEXICO AMPLIFY INTO THE SOUTHEASTERN STATES. OUR FORECAST AREA WILL THEN BE ENJOYING STACKED SURFACE AND UPPER LEVEL RIDGING FOR WEDNESDAY INTO THURSDAY. THIS RIDGING WILL PUSH THE OLD FRONTAL BOUNDARY BACK INTO THE TENNESSEE VALLEY WITH RAIN CHANCES REMAINING LOW THROUGH THE MID-WEEK PERIOD. H5 HEIGHTS NEAR 590DM AND 850MB TEMPS OF 13-14C SHOULD RESULT IN HIGH TEMPERATURES WEDNESDAY INTO THE UPPER 70S AWAY FROM THE IMMEDIATE COAST WITH A FEW SPOTS LIKELY REACHING 80. ONCE AGAIN WILL BE LOOKING FOR THE POTENTIAL FOR A WEAK SEABREEZE TO KEEP THINGS COOLER AT THE BEACHES DURING THE AFTERNOON. && .LONG TERM (THURSDAY THROUGH SUNDAY). THE STRONG UPPER LEVEL RIDGING AND UNSEASONABLY WARM TEMPERATURES THAT WILL ACCOMPANY IT SHOULD HOLD OVER THE GULF OF MEXICO AND CWA THROUGH MUCH OF THIS WEEK... BEFORE A WEAKENING COLD FRONT WITH AN ARCTIC SFC RIDGE BEHIND IT APPROACH THE AREA BY THE LATTER HALF OF THE WEEKEND OR EARLY NEXT WEEK. THE 00 UTC GFS AND 12 UTC ECMWF ARE CURRENTLY IN VERY GOOD AGREEMENT WITH THE TIMING OF THIS COLD FRONT (IN THE SUN NIGHT-MON MORNING TIME FRAME)...ALONG WITH IT BEING A LOW POP EVENT WITH THE CORE OF THE ARCTIC AIR BEHIND IT PASSING WELL TO OUR NORTH. HOWEVER...SINCE THIS SCENARIO IS QUITE FAR INTO THE FUTURE...DO NOT WANT TO WRITE OFF TSTMS AT THIS POINT...ESPECIALLY AFTER WHAT WILL BE AN UNUSUALLY LONG PERIOD OF RETURN FLOW MOISTURE. && .MARINE... SURFACE RIDGING WILL SLOWLY BUILD INTO THE NORTHEAST GULF OF MEXICO THROUGH TUESDAY AS A COLD FRONT STALLS TO THE NORTH OF THE FORECAST WATERS. THIS FRONT WILL THEN RETREAT BACK TO THE NORTH DURING THE MID-WEEK PERIOD. SURFACE RIDGING WILL REMAIN IN CONTROL OF THE NORTHEAST GULF OF MEXICO THROUGH MUCH OF THE REMAINING WORK WEEK KEEPING WINDS AND SEAS GENERALLY BELOW HEADLINE CRITERIA. VERY WARM INLAND TEMPERATURES ARE EXPECTED FOR TUESDAY AND WEDNESDAY WHICH MAY RESULT IN THE DEVELOPMENT OF FEEBLE SEA BREEZE CIRCULATIONS EACH AFTERNOON AND TURN NEAR SHORE FLOW ONSHORE. && .AVIATION... WARM MOIST LOW LEVEL WIND FLOW WILL PROVIDE CONDITIONS FOR FOG FORMATION ACROSS THE ARE TONIGHT. HIGH UNCERTAINTY REGARDING DISTRIBUTION OF LOW VISBY AND CIGS. BEST ESTIMATE IS FOR LIFR CONDITIONS AT TAE WITH IFR AT VLD ABY AND DHN. && .FIRE WEATHER... DESPITE UNSEASONABLY WARM TEMPERATURES THE NEXT SEVERAL DAYS..A MOIST LOW LEVEL AIRMASS WILL HELP KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS. NO FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH THE MIDDLE OF THE WEEK AT THIS TIME. && .HYDROLOGY... ALTHOUGH A FEW SCATTERED SHOWERS ARE EXPECTED OVER THE FORECAST AREA DURING THE NEXT 24 HOURS. RAINFALL ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT AND SHOULD HAVE VERY LITTLE IF ANY IMPACT ON AREA RIVERS AND STREAM. RESIDENTS LIVING ALONG THE MANY SWOLLEN RIVERS ACROSS THE WESTERN AND NORTHERN FORECAST AREA SHOULD CONTINUE TO MONITOR THE RIVERS AND LAKES AHPS WEB PAGE: (HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=TAE) FOR THE LATEST RIVER STAGES AND FORECASTS. THE LATEST FLOOD WARNINGS AND FLOOD STATEMENTS CAN ALSO BE FOUND AT THIS SITE AND ON NOAA WEATHER RADIO. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 56 76 55 78 54 / 10 10 05 0 0 PANAMA CITY 62 74 61 75 58 / 20 20 10 0 0 DOTHAN 58 74 58 78 57 / 45 35 10 05 0 ALBANY 56 75 58 78 56 / 25 25 10 05 0 VALDOSTA 54 77 55 79 54 / 10 10 0 0 0 CROSS CITY 54 78 53 81 52 / 10 10 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ AVIATION/FIRE WEATHER...GOREE SYNOPSIS/SHORT TERM/MARINE/HYDROLOGY...MROCZKA LONG TERM...GOULD fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1117 AM CST MON DEC 15 2008 UPDATED AVIATION DISCUSSION .SHORT TERM...TODAY TEMP AND WIND TRENDS MAIN CONCERN TODAY. LATEST RUC/NAM RAW TEMPS ARE FAIRLY CLOSE TO REALITY THIS MORNING WHILE GFS IS TOO WARM. HAVE FOLLOWED RUC/NAM GIVING LITTLE REBOUND TODAY...AND HIGHS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. NAM MOS PLUS A FEW DEGREES. 07Z SFC ANLYS STILL SHOWS ANOTHER ISALLOBARIC MAX PASSAGE THROUGH IA SO EXPECT WINDS TO REMAIN CONSISTENT EARLY THIS MORNING...THEN DIMINISH SOMEWHAT LATER TODAY. HOWEVER WITH OUR ARCTIC AIRMASS IN PLACE IT WILL KEEP US IN WIND CHILL CRITERIA ALL BUT SERN SECTIONS TIL NOON...AND NRN THREE TIERS TIL MIDNIGHT. THUS WILL KEEP CURRENT HEADLINES IN PLACE...BUT EXTEND NRN ONE TIL 06Z. VSBYS HAVE BEEN A MILE OR LESS AT KEST THIS MORNING...AND OFTEN DOWN TO 1/4SM IN BLOWING SNOW...SO HAVE EXTENDED WINTER WX ADVY FOR BLOWING SNOW TIL 8AM. DOT ROAD REPORTS STILL SHOW LIMITED VSBYS IN THESE AREAS. SATELLITE AND MODEL TRENDS AS WELL AS MANUAL OBSERVATIONS WOULD INDICATE THAT AWOS/ASOS CIGS ARE TOO BULLISH ACROSS IA THIS MORNING LIKELY DUE TO BLOWING SNOW AND ELEVATED ICE CRYSTALS. THUS WILL GO WITH MORE SUNSHINE THAN NEPHANLYS WOULD EXPECT. .LONG TERM...TONIGHT THROUGH SUNDAY BRIEF PERIOD OF QUIET WEATHER GIVES WAY TO RATHER STRONG OVERRUNNING EVENT WITH MOISTURE TRANSPORT AND H850 FLOW LIFTING OVER A THE EXISTING BAROCLINIC ZONE FOR TUESDAY FOR A BROAD UPGLIDE...WITH H300 JET MAX OF 150 KTS ALSO AIDING BROAD AREA OF LIFT DURING THE DAYTIME HOURS. BUFKIT SOUNDINGS SUGGEST THAT FAIRLY UNIFORM CONDITIONS WILL TRANSLATE FROM SOUTHWEST IA THROUGH TO EASTERN SECTIONS BY EVENING. QUESTION OF THE DAY IS NOT SO MUCH THE SNOW:WATER RATIO...BUT THE AMOUNT OF QPF IS THE KEY. SO FAR THE EURO HAS BEEN CONSISTENT WITH PAST 4 OR MORE RUNS WITH NEARLY .40 TO .45 OF QPF. GFS/NAM HAVE BEEN SLIGHTLY LESS RELIABLE FROM RUN TO RUN BUT CONTINUE TO TREND A BIT LESS IN AVAILABLE MOISTURE. THE 00Z UKMET IS NEARER .30 TOTAL AS WELL. IN ANY EVENT IT LOOKS LIKE A PRETTY HIGH END ADVISORY FOR THE SOUTH TWO THIRDS OF THE FORECAST AREA WITH THE POSSIBILITY OF BREACHING 6+ INCH AMOUNTS SOMEWHERE SOUTH OF OF HIGHWAY 30. TIME CROSS SECTIONS SHOW FAIRLY GOOD LIFT IN THE DENDRITIC GROWTH ZONE FOR THE EVENT WHICH SHOULD LAST ABOUT 4 TO 6 HOURS ONCE IT BEGINS. THIS TRACKS FAIRLY WELL WITH ABOUT 1 INCH PER HOUR SNOWFALL RATES. AFTER SOME DELIBERATION HAVE DECIDED TO GO WITH A WATCH FOR TUESDAY FROM 12Z THROUGH 06Z WED. MOST OF THE SNOW WILL BE OVER WEST PRIOR TO 21Z BUT SHOULD CONTINUE INTO THE EVENING HOURS EAST. THOUGH BLOWING SNOW WILL NOT BE A PROBLEM SNOWFALL OF EVEN 4 TO 5 INCHES DURING THE DAY WILL CAUSE SOME PROBLEMS FOR AREA TRAVELERS. NEWEST 06Z NAM A BIT SLOWER THAN THE 00Z RUN...BUT TRENDS REMAIN APPROXIMATELY THE SAME. THE BULK OF THE SNOW WILL BE OVER BY THE EVENING HOURS AND SOME CLEARING EXPECTED BY MORNING. HAVE TRIMMED MINS WEST SECTIONS BASED ON THIS THINKING. QUICK BREAK FOR WED BEFORE THE NEXT UPSTREAM WAVE AFFECTS THE REGION FOR LATER ON THURSDAY. MODELS NOT IN GREAT AGREEMENT RIGHT NOW CONCERNING THE AMOUNT OF WARM AIR GETTING INTO THE SYSTEM. GFS MUCH WARMER THAN THE EURO...AND STRUCTURE OF THE SYSTEM IS MUCH DIFFERENT...FARTHER NORTH AND TRACK IS ALSO DIFFERENT. HAVE NOT MADE TOO MANY CHANGES TO GOING PTYPE AND POP GIVEN CURRENT UNCERTAINTY. THE EURO MAINTAINS A MORE SOUTHERLY TRACK AND IS ALSO A TOUCH SLOWER. THERE WILL BE ANOTHER SYSTEM BY LATE FRIDAY AND SATURDAY FOLLOWED BY A SHOT OF ARCTIC AIR ON THE WEEKEND. BOTH THE EURO AND GFS STILL AGREE ON OVERALL PATTERN IN THIS REGARD. && .AVIATION...15/18Z DIMINISHING WIND SHOULD PRECLUDE ANY VSBY ISSUES AT KMCW THIS AFTN. OTHERWISE...VFR CONDITIONS THROUGH 12Z OR BEYOND. SNOW WILL BE DEVELOPING AFT 14Z TUESDAY...WITH CIELINGS AND VSBY COMING DOWN ACCORDINGLY WEST TO EAST THRU 18Z. DUE TO UNCERTAINTY OF INTENSITY BEFORE 18Z...HAVE ONLY BROUGHT CONDITIONS DOWN TO HIGH END IFR AT WESTERN SITES...AND MVFR AT EASTERN SITES. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVY TONIGHT THROUGH MIDDAY MONDAY /18Z MONDAY/ SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD- CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS- POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA ADAIR-ADAMS-CLARKE-DECATUR-LUCAS-RINGGOLD-TAYLOR-UNION. WIND CHILL ADVY TONIGHT THROUGH TUESDAY EVENING /06Z TUESDAY/ EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER. WINTER STORM WATCH TUESDAY MORNING THROUGH TUESDAY EVENING /12Z TUESDAY THROUGH 06Z WEDNESDAY/...FOR GREENE-BOONE-STORY-MARSHALL- TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON -WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR -RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS. && $$ SHORT TERM...BSS LONG TERM...REV AVIATION...MOYER ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1043 AM MST MON DEC 15 2008 .UPDATE... 1000 AM MST MON DEC 15 2008 JUST COMPLETED AN UPDATE. MAIN CHANGE WAS TO LOWER MAX TEMEPRATURES FOR THE DAY. AREAS RECEIVING SUN ARE STILL VERY SLOW TO RECOVER. DO ONLY HAVE A THIN LAYER OF SNOW BUT CURRENT 4 INCH SOIL TEMPERATURE IS BETWEEN 30 AND 31 DEGREES. DIFFERENT STORY OVER THE SOUTHEAST THIRD OF THE AREA WITH A PERSISTENT CLOUD DECK DUE TO MID/UPPER LEVEL JET IN THE AREA THAT LOOKS TO STRENGTHEN AND EVEN SPREAD NORTH DURING THE DAY. RUC 2 METER/NUMERICAL GUIDANCE/SOUNDINGS ARE ALL SIMILAR AND SUPPORT GOING COOLER...ESPECIALLY IN THE NORTHEAST...WHERE THE COLD AIR IS DEEPEST. SO ADJUSTED ACCORDINGLY ACROSS THE AREA. ALSO ADJUSTED CLOUD COVER BASED ON CURRENT CONDITIONS AND EXPECTED TRENDS. WINDS ARE CLOSE BUT JUST ADJUSTED SLIGHTLY BASED ON LATEST RUC/CURRENT OBSERVATIONS. ALSO ADJUSTED HOURLY TRENDS ON TEMPERATURES AND DEWPOINTS. BULLER && .DISCUSSION...FORECAST CONCERNS ARE TEMPERATURES/WINDS/WIND CHILL READINGS AND PRECIPITATION CHANCES IN THE SHORT TERM. RECORD LOW TEMPERATURES WERE REACHED IN YUMA COUNTY LAST NIGHT AND AGAIN THIS MORNING (-14F AS OF 2 AM MST). BURLINGTON COLORADO HAS BROKEN THEIR RECORD THIS MORNING AS WELL AND GOODLAND IS WITHIN ONE DEGREE OF TYING THEIRS. STATEMENTS WILL BE ISSUED A BIT LATER THIS MORNING. TODAY-WEDNESDAY NIGHT...PRECIPITATION CHANCES WILL INCREASE LATE TONIGHT AND CONTINUE THROUGH THE AFTERNOON HOURS TUESDAY AHEAD OF LONGWAVE TROUGH COVERING THE WESTERN 1/3-1/4 OF THE WESTERN PART OF THE COUNTRY. SOUTH TO SOUTHEAST WINDS WILL INCREASE LOW LEVEL MOISTURE WHILE MID LEVEL MOISTURE MOVES OVER THE AREA FROM THE WEST/SOUTHWEST. TOTAL ACCUMULATIONS AN INCH OR LESS. ONCE THIS SYSTEM LEAVES THE AREA PRECIPITATION CHANCES INCREASE AGAIN WEDNESDAY NIGHT INTO THURSDAY AS ANOTHER PIECE OF ENERGY AND MOISTURE MOVE ACROSS THE NORTHERN HALF OF THE AREA AHEAD OF A WELL ORGANIZED SHORTWAVE MOVING THROUGH COLORADO. TOTAL SNOW WITH THIS SYSTEM WELL BELOW AN INCH AT PRESENT TIME. WIND CHILL ADVISORY MAY BE NEEDED TONIGHT AS SOUTH TO SOUTHEAST WINDS REMAIN ABOVE 10 MPH AND TEMPERATURES HOLD IN THE SINGLE DIGITS. WILL LET THE NEXT SHIFT EVALUATE THE 12Z MODELS AND FINE TUNE THE WINDS AND TEMPS. WILL MENTION WIND CHILLS APPROACHING -15F IN THE HWO AS A HEADS UP. HIGH AND LOW TEMPERATURES WILL BE TRICKY OVER THE NEXT FEW DAYS GIVEN DISAGREEMENTS IN 850 TEMPS...EXTENT OF CLOUD COVER AND SURFACE FEATURE POSITIONS. TRIED NOT TO STRAY TOO FAR FROM CURRENT FORECAST GIVEN THE UNCERTAINTY. HIGH TEMPS TODAY IN THE TEENS...COLDEST ACROSS THE NORTHEAST AND EAST WHERE WINDS LIGHTEST AND PROXIMITY TO ARCTIC HIGH THE CLOSEST. MINS TONIGHT AROUND ZERO EAST/NORTHEAST AND SINGLE DIGITS ELSEWHERE...COULD BE A TAD ON THE COLD SIDE IF CLOUDINESS IMPACTS LACK OF RADIATIONAL COOLING. FOR TUESDAY TEMPERATURES SLOWLY WARM CLOSE TO 20 ACROSS THE EAST/NORTHEAST WITH UPPER 20S TO LOW 30S ACROSS THE FAR SOUTHWEST AND WEST. MINS TUESDAY NIGHT IN THE SINGLE DIGITS. FOR WEDNESDAY WARMED TEMPS UP ANOTHER FEW DEGREES WITH LOW 20S EAST/NORTHEAST AND LOW 30S FAR WEST/SOUTHWEST. THURSDAY-SUNDAY...NO CHANGES MADE AT PRESENT TIME. 07 && .AVIATION... 1034 AM MST MON DEC 15 2008 FOR THE 18 TAF CYCLE...FOR KGLD...VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MOST OF THE TAF PERIOD. CURRENT SCT HIGH LEVEL CLOUDS WILL BEGIN TO GIVE WAY TO LOWER LEVEL CEILINGS BY ABOUT 06Z. BETWEEN 09Z AND 14Z MVFR CEILINGS MAY IMPACT KGLD...BUT WAS NOT CONFIDENT ENOUGH TO MAKE IT A CEILING IN A PREVAILING TAF LINE. BETWEEN 06Z AND ABOUT 17Z...WINDS WILL INCREASE FROM THE SOUTHEAST TO AROUND THE 13G23KT RANGE. AFTER 17Z...WINDS WILL DECREASE TO AROUND 10KT FROM THE SOUTH UNDER VFR CEILINGS. FOR KMCK...VFR CEILINGS AND LIGHT SNOW SEEM MORE LIKELY BETWEEN 09Z AND 16Z AS WINDS ALSO INCREASE FROM THE SOUTHEAST TO AROUND THE 12G19KT RANGE. AFTER 16Z...WINDS WILL DIMINISH FROM THE SOUTH TO AROUND 10KT AS THE CHANCE FOR SNOW LESSENS AND MVFR CEILINGS RAISE UP TO VFR CEILINGS. BLM && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 411 PM EST TUE DEC 15 2008 .SHORT TERM... WATER VAPOR IMAGERY AND RUC CONTINUES TO SHOW A LONGWAVE TROUGH OVER HUDSON BAY. A CLOSED OVER WESTERN OREGON IS SWINGING THROUGH THE BASE OF THE LONGWAVE TROUGH. AS ONE SHORTWAVE ROTATING THROUGH THE BASE OF THE LONGWAVE MOVES EAST THIS AFTERNOON AND ANOTHER IS SWEEPING INTO THE AREA. SURFACE ANALYSIS DEPICTS A LOW OVER WEST CENTRAL QUEBEC WITH A COLD FRONT DRAPED SOUTH THROUGH NEW YORK STATE. A LARGE RIDGE STRETCHES FROM EASTERN MONTANA SOUTHEAST TO A LARGE HIGH OVER NORTHWEST IOWA. TIGHT GRADIENT BETWEEN THESE TWO SYSTEM CONTINUES TO CAUSE WINDS TO GUSTS OVER 40 MPH OVER THE KEWEENAW PENINSULA. A THERMAL TROUGH WRAPPING AROUND THE BACK OF THE LOW CONTINUE TO BRING TEMPERATURE AT 850MB TO -24C WHICH IS SIGNIFICANT ENOUGH TO PRODUCE LES OVER WESTERN U.P. AND NEAR LAKE SUPERIOR EAST OF MUNISING. HOWEVER...THE AIR MASS IS QUITE DRY WHICH STILL LIMITS THE AMOUNT OF SNOWFALL. THE LONGWAVE TROUGH WILL REMAIN OVER HUDSON BAY TONIGHT. A SHORTWAVE SWINGING THROUGH THE BASE OF THE TROUGH WILL SHIFT OVER SOUTH CENTRAL CANADA...WITH WEAKER SHORTWAVES SLIDING INTO THE LOWER GREAT LAKES AND SOUTHEAST QUEBEC. A LOW CENTER...WHICH IS PART OF THE LONGWAVE TROUGH...WILL DEEPENING OVER NORTHERN CALIFORNIA. THE SURFACE HIGH WILL PUSH INTO SOUTHERN WISCONSIN AND BLANKET MUCH OF THE GREAT LAKES REGION. 850MB TEMPERATURES WILL REMAIN AROUND -21C OVER LAKE SUPERIOR TONIGHT AS DRY AIR INVADES THE FORECAST AREA WITH THE DEPARTURE OF THE LOW. THE COLD AIR ADVECTION THAT CAUSED THE TEMPERATURES DIP INTO THE SINGLE DIGITS F OVER THE U.P. THIS AFTERNOON WITH A FEW READINGS INTO THE NEGATIVE VALUES OVER THE FAR WEST WILL DIP TO AROUND 15F BELOW TONIGHT OVER THE WEST AND TO AROUND ZERO OVER THE EASTERN U.P. ADVISORY HEADLINE MAY BE NEEDED FOR TONIGHT TO COVER COMBINATION OF CONTINUED LES/BLOWING SNOW AND FALLING WIND CHILLS. MESOSCALE MODEL QPF AND ASSOC SNOW/WATER RATIOS SUGGEST TOTAL SNOWFALL AMOUNTS OF 4-8 INCHES ARE POSSIBLE OVER THESE AREAS BEFORE BACKING WINDS SHIFT LES BANDS OUT OVER LAKE SUPERIOR LATE TONIGHT. INCREASINGLY ANTICYCLONIC FLOW AND WINDS BACKING WEST SOUTHWEST WILL ALLOW FOR CLEARING SKIES FOR ALL BUT THE KEWEENAW PENINSULA BY LATE THIS EVENING. WITH THE WEAK SURFACE WINDS THROUGH MUCH OF THE NIGHT ALONG WITH FALLING TEMPERATURES...WIND CHILLS WILL LOWER INTO THE 25 TO 30 BELOW ZERO RANGE. THUS WIND CHILL ADVISORIES OVER THE REMAINDER OF THE WEST HALF OF UPPER MICHIGAN WILL CONTINUE TONIGHT INCLUDING DELTA COUNTY WHICH WILL ALSO BE EXPOSED TO COLD ADVECTION AND FALLING TEMPERATURES IN A WESTERLY FLOW. BITTER COLD WIND CHILLS WILL STILL WARRANT ADVISORIES INTO TUESDAY MORNING BUT LES AND BLOWING SNOW SHOULD BE TAPERING OFF OVER THE KEWEENAW PENINSULA. WILL KEEP A SLIGHT CHANCE LATE TUESDAY ALONG THE WISCONSIN BORDER FOR SLOWER ARRIVAL OF WARM AIR ADVECTION SNOW AHEAD OF SYSTEM. THE MID LEVEL LOW WILL REMAIN OVER WESTERN HUDSON BAY. A WEAK SHORTWAVE WILL SLIDE INTO WISCONSIN. ANOTHER SHORTWAVE WILL DIG DEEPER OVER SOUTHERN MANITOBA. THE SURFACE HIGH WILL TRACK THROUGH THE GREAT LAKES TO SOUTHERN QUEBEC. THE 850MB TEMPERATURE WILL INCREASE TO -18C OVER LAKE SUPERIOR. THE WINDS WILL BACK TO THE SOUTHWEST AFTER THE HIGH MOVES EAST KILLING OFF OF THE LES. .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... TUESDAY NIGHT THROUGH THURSDAY MORNING...THIS PERIOD IS DOMINATED BY A STRONG UPPER TROUGH IN EASTERN CANADA. THE CORRESPONDING WEST TO SOUTHWESTERLY FLOW OVER THE NORTHERN STATES WILL MOVE A REGION OF ISENTROPIC LIFT...AS SEEN ON THE 285K SFC...INTO THE FA EARLY TUESDAY NIGHT. KEPT SOME PARTS OF THE INHERITED FORECAST WITH CATEGORICAL POPS IN THE EAST. DECIDED TO INCREASE POPS ELSEWHERE. WHILE I DO NOT THINK AREAS WEST OF MARQUETTE AND DICKINSON COUNTIES WILL SEE MUCH SNOW/QPF...THINK THERE IS ENOUGH CONFIDENCE THAT MEASURABLE PRECIPITATION WILL OCCUR TO WARRANT HIGHER POPS. FOR NOW HAVE A GENERAL 2 TO 3 INCHES FOR TUESDAY NIGHT ACROSS AREAS EAST OF A LINE FROM BARAGA TO MARENISCO...AN INCH OR LESS ELSEWHERE. AREAS ALONG LAKE MICHIGAN AND IN LUCE COUNTY COULD SEE UP TO 4 INCHES OF SNOW OR CLOSE TO ADVISORY CRITERIA. AS FAR AS THE DETAILS GO...PER BUFKIT GUIDANCE...MOISTURE PROFILES W.R.T ICE ARE FAIRLY DEEP AND GIVEN THE EXPECTED COLUMN TEMPERATURES OF LESS THAN -15...ICE WILL BE DOMINANT IN THE CLOUD...ALSO THE DGZ IS AROUND 10KFT DEEP SO THINK SLR COULD PUSH 25:1. MODEL DERIVED SLR WOULD SUGGEST RATIOS EVEN HIGHER...30/40:1. HARD TO GO THIS HIGH IN A SYNOPTIC ENVIRONMENT...WILL KEEP 25:1 FOR NOW. MOISTURE/LIFT/LOW CPD/S WITH THIS FEATURE QUICKLY EXIT TO THE NORTHEAST ON WEDNESDAY. LES PROCESSES WILL ALLOW FOR -SHSN TO CONTINUE ACROSS THE KEWEENAW AND AREAS EAST OF MARQUETTE THROUGH THURSDAY MORNING. ONLY LIGHT ACCUMULATIONS EXPECTED GIVEN INVERSION HEIGHT BLO 5KFT. HEAVIER LES WILL BE CONFINED TO THE EASTERN CANADIAN SHORELINES OF LAKE SUPERIOR. THURSDAY MORNING THROUGH SUNDAY...BY THURSDAY AFTN...THE STRONG HUDSON BAY LOW/EASTERN CANADA TROUGH WILL PUSH EAST INTO THE NEW FOUNDLAND/CANADIAN MARITIES THURSDAY NIGHT...THIS WILL GIVE WAY TO A DEVELOPING LOW OUT OF THE U.S. CENTRAL PRAIRIES. FOR THE LAST COUPLE DAYS THE GFS HAS BEEN ADVERTISING THAT THIS LOW WILL TRACK OVER NORTHERN LAKE MICHIGAN WHICH WOULD YIELD A HIGH IMPACT HEAVY SNOW EVENT FOR THE UPPER PENINSULA. THESE RUNS HAD BEEN THOUGHT TO BE OUTLIERS...AND PERHAPS STILL ARE...THOUGH BOTH THE 12Z ECMWF/GLBL-GEM HAVE TRENDED TOWARDS THE HIGH IMPACT GFS SOLUTION...OPTED TO TREND POP UPWARDS...TO 50%...AS A RESULT OF THESE MODEL TRENDS. LITTLE CHANGES MADE INTO SATURDAY AND SUNDAY AS THE OVERALL PATTERN WILL SHIFT TO AN LES REGIME IN THE WAKE OF WHEREVER THE FRIDAY SYSTEM PASSES. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... AT CMX...IFR TO VLIFR CONDITIONS WILL CONTINUE...AS STRONG WESTERLY WINDS AND COLD AIR CROSSING LAKE SUPERIOR CREATE PLENTY OF LAKE EFFECT SNOW SHOWERS. THIS SNOW SHOULD BLOW AROUND WITH BLIZZARD CONDITIONS OFF AND ON...MAINLY THROUGH THIS AFTERNOON. SAW WILL NOT BE NOT BE AS LIKELY TO EXPERIENCE BLIZZARD CONDITIONS. HOWEVER...GUSTY WINDS TO 35 KNOTS SHOULD STILL CREATE BLOWING SNOW AND REDUCE VIS FROM 1 TO 3 SM FROM AT TIME THIS AFTERNOON. CONDITIONS WILL IMPROVE WITH DECREASING WINDS THIS EVENING...AS LAKE EFFECT SNOW SHOWERS END AND CEILINGS DISSIPATE OVERNIGHT. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... GALES WILL CONTINUE...BEFORE WINDS DIMINISH FROM WEST TO EAST TONIGHT AS THE HIGH MOVES INTO THE AREA AND LOW LEAVES. FREEZING SPRAY WILL BECOME AN ISSUE AND REMAIN SO THROUGH TUESDAY MORNING...AS PLENTY OF COLD AIR SETTLES INTO THE REGION. FOR TUESDAY NIGHT AND WEDNESDAY...A LOW PRESSURE TROUGH SHOULD QUICKLY SWING FROM THE LOWER MISSISSIPPI VALLEY TO THE LOWER GREAT LAKES. HIGH PRESSURE WILL THEN MOVE FROM THE CENTRAL PLAINS STATES WEDNESDAY... TO THE UPPER GREAT LAKES THURSDAY MORNING...AND THE LOWER GREAT LAKES THURSDAY EVENING. LOW PRESSURE ACROSS THE CENTRAL PLAINS THURSDAY AFTERNOON SHOULD SHIFT TO THE LOWER GREAT LAKES AND EAST COAST FRIDAY. AS THE SYSTEM MOVES THROUGH AGAIN WINDS WILL INCREASE TO GUSTS TO 30 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002- 004-084. WIND CHILL ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO 12 PM EST /11 AM CST/ TUESDAY FOR MIZ002-004-005-011>013-084. BLIZZARD WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ001-003. WIND CHILL ADVISORY UNTIL 11 AM CST TUESDAY FOR MIZ009-010. WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ006-007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST TUESDAY FOR LSZ265- 267. GALE WARNING UNTIL 3 AM EST TUESDAY FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR LSZ266. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ265. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LSZ244-245-263-264. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ245-246. GALE WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR LSZ162- 242-243. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST TUESDAY FOR LSZ247>251. GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LSZ248-249. HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST /9 AM CST/ TUESDAY FOR LSZ240>244. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ250. GALE WARNING UNTIL 1 AM EST TUESDAY FOR LSZ251. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ221-248-250. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...DLG LONG TERM...PEARSON AVIATION...DLG MARINE...DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1236 PM EST TUE DEC 16 2008 .SHORT TERM... WATER VAPOR IMAGERY AND RUC SHOWING A LONGWAVE TROUGH OVER HUDSON BAY. A CLOSED OVER WESTERN OREGON IS SWINGING THROUGH THE BASE OF THE LONGWAVE TROUGH. A SHORTWAVE ROTATING THROUGH THE BASE OF THE LONGWAVE. SURFACE ANALYSIS DEPICTS A LOW OVER SOUTHERN JAMES BAY WITH A COLD FRONT DRAPED SOUTH THROUGH THE EASTERN OHIO RIVER VALLEY. A RIDGE STRETCHES FROM SOUTHERN ALBERTA SOUTHEAST THROUGH KANSAS. TIGHT GRADIENT WRAPPING AROUND THE BACK OF THIS LOW IS CAUSING WINDS TO GUSTS OVER 40 MPH OVER THE KEWEENAW PENINSULA. A THERMAL TROUGH WRAPPING AROUND THE BACK OF THE LOW CAUSING TEMPERATURE AT 850MB TO DROP TO -24C WHICH IS SIGNIFICANT ENOUGH TO PRODUCE LES OVER WESTERN U.P. AND NEAR LAKE SUPERIOR EASTER OF MUNISING. HOWEVER...THE AIR MASS IS QUITE DRY WHICH LIMITS THE AMOUNT OF SNOWFALL. 850MB TEMPERATURES WILL INCREASE TO AROUND -21C OVER WESTERN LAKE SUPERIOR AND TO -19C OVER EASTERN LAKE SUPERIOR TODAY AS THE THERMAL TROUGH SHIFTS EAST THIS AFTERNOON. LINGERING DEEP MOISTURE AND WEAK ENHANCEMENT SHOULD EQUATE TO MODERATE SNOW ACCUMULATIONS OVER THE WESTERN COUNTIES FAVORED IN A WEST NORTHWEST FLOW...BEFORE THE DEEPER MOISTURE LIFTS NORTHEAST IN THE AFTERNOON WITH THE DEPARTING SYSTEM. STRONG WEST NORTHWEST WINDS BOOSTED BY 4-6 MB 3 HR PRESSURE RISES IN THE WAKE OF THE FRONTAL PASSAGE. WIND GUSTS TO 45 MPH ARE ALMOST A CERTAINTY OVR KEWEENAW PENINSULA TODAY. COLD AIR ADVECTION CAUSING TEMPERATURES TO DIP INTO THE SINGLE DIGITS F OVER THE U.P. WITH A FEW READINGS INTO THE NEGATIVE VALUES OVER THE FAR WEST. THE LAKE EFFECT SNOWS ALONG WITH THE STRONG WIND AND LOW TEMPERATURES ARE CAUSING BLIZZARD LIKE CONDITIONS OVER THE KEWEENAW PENINSULA. .LONG TERM...TONIGHT AND LATER BLIZZARD CRITERIA WILL DIMINISH TONIGHT ALTHOUGH ANOTHER ADVISORY HEADLINE MAY BE NEEDED FOR TONIGHT TO COVER COMBINATION OF CONTINUED LES/BLOWING SNOW AND FALLING WIND CHILLS. MESOSCALE MODEL QPF AND ASSOC SNOW/WATER RATIOS SUGGEST TOTAL SNOWFALL AMOUNTS OF 4-8 INCHES ARE POSSIBLE OVER THESE AREAS BEFORE BACKING WINDS SHIFT LES BANDS OUT OVER LAKE SUPERIOR LATE MON NIGHT. WIND CHILLS WILL FINAL ISSUE TO DEAL WITH AS TEMPERATURES WILL CONTINUE INTO TONIGHT WITH CONTINUED STRONG COLD ADVECTION ON THE HEELS OF GUSTY WESTERLY WINDS. INCREASINGLY ANTICYCLONIC FLOW AND WINDS BACKING WEST SOUTHWEST WILL ALLOW FOR CLEARING SKIES FOR ALL BUT THE KEWEENAW PENINSULA BY LATE THIS EVENING. SURFACE WINDS OF 10-15 MPH EXPECTED THROUGH MUCH OF THE NIGHT ALONG WITH TEMPS FALLING INTO THE -10 TO -15F RANGE WILL ALLOW FOR WIND CHILLS TO LOWER INTO THE 25 TO 30 BELOW ZERO RANGE. ISSUED WIND CHILL ADVISORIES OVER THE REMAINDER OF THE WEST HALF OF UPPER MICHIGAN...EVEN INCLUDING DELTA COUNTY WHICH WILL ALSO BE EXPOSED TO COLD ADVECTION AND FALLING TEMPERATURES IN A WESTERLY FLOW. BITTER COLD WIND CHILLS WILL STILL WARRANT ADVISORIES INTO TUESDAY MORNING BUT LES AND BLOWING SNOW SHOULD BE TAPERING OFF OVER THE KEWEENAW PENINSULA. 00Z MODELS TRENDED SOMEWHAT SLOWER AND MAYBE SLIGHTLY FARTHER SOUTH WITH TRACK OF NEXT SYSTEM FOR LATE TUE INTO TUE NIGHT. TRIMMED BACK POPS TO SLIGHT CHANCE LATE TUESDAY ALONG THE WISCONSIN BORDER FOR SLOWER ARRIVAL OF WAA SNOW AHEAD OF SYSTEM. KEPT IN CATEGORICAL POPS ALONG THE SOUTHEAST COUNTIES FOR TUESDAY NIGHT IN PROXIMITY TO BETTER ISENTROPIC ASCENT WITH SYSTEM AND TAPERED BACK POPS TO CHANCE CATEGORY OVER THE WEST. LINGERING COLD AIRMASS WITH 850 MB TEMPS OF -15 TO -18C AND SLOW REBOUND FROM TONIGHT`S BITTER COLD LOWS WILL RESULT IN HIGHS IN THE SINGLE DIGITS ABV ZERO WEST TO BARELY CRACKING 10F OVER THE EASTERN INTERIOR. TEMPERATURES WILL BE SLIGHTLY WARMER ALONG THE GREAT LAKES. SYSTEM DEPARTS FAIRLY QUICKLY EAST BY WED LEAVING ONLY SOME LINGERING LIGHT SYSTEM SNOW IN THE FAR EAST AND LINGERING LAKE EFFECT SNOW SHOWERS OVER THE KEWEENAW AND LAKE SUPERIOR IN A W-SW CONVERGENT FLOW AND STILL FAIRLY COLD 850 MB TEMPS OF -16 TO -18C ENTRENCHED OVER THE REGION. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... AT CMX...IFR TO VLIFR CONDITIONS WILL CONTINUE...AS STRONG WESTERLY WINDS AND COLD AIR CROSSING LAKE SUPERIOR CREATE PLENTY OF LAKE EFFECT SNOW SHOWERS. THIS SNOW SHOULD BLOW AROUND WITH BLIZZARD CONDITIONS OFF AND ON...MAINLY THROUGH THIS AFTERNOON. SAW WILL NOT BE NOT BE AS LIKELY TO EXPERIENCE BLIZZARD CONDITIONS. HOWEVER...GUSTY WINDS TO 35 KNOTS SHOULD STILL CREATE BLOWING SNOW AND REDUCE VIS FROM 1 TO 3 SM FROM AT TIME THIS AFTERNOON. CONDITIONS WILL IMPROVE WITH DECREASING WINDS THIS EVENING...AS LAKE EFFECT SNOW SHOWERS END AND CEILINGS DISSIPATE OVERNIGHT. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... GALES WILL CONTINUE...BEFORE WINDS DIMINISH FROM WEST TO EAST TONIGHT. A FEW STORM FORCE GUSTS...TO 50 KTS...MAY STILL BE POSSIBLE EAST TODAY. FREEZING SPRAY WILL BECOME AN ISSUE AND REMAIN SO THROUGH TUESDAY MORNING...AS PLENTY OF COLD AIR SETTLES INTO THE REGION. AT 12Z...STRONG LOW PRESSURE JUST NORTHEAST OF LAKE SUPERIOR WILL CONTINUE ON ITS NORTHEASTWARD TRACK...TO NORTHERN QUEBEC LATE TUESDAY AFTERNOON. STRONG HIGH PRESSURE IS EXPECTED TO SPILL OVER THE CENTRAL PLAINS FROM WESTERN CANADA TODAY. IT SHOULD THEN SHIFT OVER THE GREAT LAKES TUESDAY...BEFORE MOVING TO THE NEW ENGLAND STATES TUESDAY EVENING. FOR TUESDAY NIGHT AND WEDNESDAY...A LOW PRESSURE TROUGH SHOULD QUICKLY SWING FROM THE LOWER MISSISSIPPI VALLEY TO THE LOWER GREAT LAKES. HIGH PRESSURE WILL THEN MOVE FROM THE CENTRAL PLAINS STATES WEDNESDAY...TO THE UPPER GREAT LAKES THURSDAY MORNING...AND THE LOWER GREAT LAKES THURSDAY EVENING. LOW PRESSURE ACROSS THE CENTRAL PLAINS THURSDAY AFTERNOON SHOULD SHIFT TO THE LOWER GREAT LAKES AND EAST COAST FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002- 004-084. WIND CHILL ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO 12 PM EST /11 AM CST/ TUESDAY FOR MIZ002-004-005-011>013-084. BLIZZARD WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ001-003. WIND CHILL ADVISORY UNTIL 11 AM CST TUESDAY FOR MIZ009-010. WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ006-007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST TUESDAY FOR LSZ265- 267. GALE WARNING UNTIL 3 AM EST TUESDAY FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR LSZ266. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ265. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LSZ244-245-263-264. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ245-246. GALE WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR LSZ162- 242-243. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST TUESDAY FOR LSZ247>251. GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LSZ248-249. HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST /9 AM CST/ TUESDAY FOR LSZ240>244. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ250. GALE WARNING UNTIL 1 AM EST TUESDAY FOR LSZ251. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ221-248-250. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...DLG LONG TERM...VOSS AVIATION...DLG MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1159 AM CST MON DEC 15 2008 .UPDATE... ADDED AVIATION DISCUSSION FOR 18Z TAFS BELOW... && .DISCUSSION... THE FORECAST CHALLENGES CENTER ON WIND CHILLS THE NEXT 18 HOURS...THOUGH ATTENTION IN FUTURE SHIFTS WILL BE TURNING TO TUES/TUES EVE SNOW EVENT AND THEN ANOTHER POSSIBLE ONE FOR THU. LATEST SURFACE ANALYSIS REVEALS 993MB LOW LIFTING NORTHEAST INTO CENTRAL ONTARIO. NEARLY 50MB DIFFERENCE BETWEEN THIS FEATURE AND ARCTIC HIGH PRESSURE CENTER EXPANDING OVER THE CTRL PLAINS. RESULTANT WINDS CONTINUE SUSTAINED AT 25 TO 30 MPH THIS MORNING WITH OCCASIONAL GUSTS TO 40 MPH. TEMPS CONTINUE TO FALL THROUGH THE SINGLE DIGITS BELOW ZERO WITH NEGATIVE DOUBLE DIGITS TO THE START THE DAY IN WEST CTRL MN. WIND CHILLS HAVE BEEN BETWEEN 25 AND 40 BELOW ZERO ACROSS THE AREA FROM EAST TO WEST THROUGH THE EARLY MORNING. OVERALL...AIR TEMPS ARE 35 TO 45 DEGREES COOLER ACROSS THE AREA THAN JUST 24 HOURS AGO! WHAT A CLASSIC EARLY WINTER CYCLONE. CURRENT WINDS SHOULD CONTINUE NEARLY THE SAME IN SPEED AND GUST THROUGH THE MORNING WITH AREA AND UPSTREAM WIND PROFILERS MEASURING 925MB WINDS AT 30 KTS AND RUC SOUNDINGS DIAGNOSING CONTINUED STEEP LOW LEVEL LAPSE RATES. THESE WINDS WILL VERY GRADUALLY EASE THIS AFTN AND WITH THAT THE BLOWING SNOW SHOULD TOO. 1000-850MB COLD AIR ADVECTION ALSO PROGGED TO ACCORDINGLY DIMINISH GRADUALLY. SO TEMPS ARE THOUGHT TO BE NEARLY STEADY THIS MORNING FOLLOWED BY CLIMBING A HANDFUL OF DEGREES THIS AFTN. WIND CHILLS THIS ENTIRE TIME THOUGH SHOULD REMAIN IN ADVISORY CRITERIA WITH WARNING CRITERIA CONTINUING ACROSS THE WEST. SO HAVE EXTENDED HEADLINES. WRN WI LIKELY TO CONTINUE WITH WIND INTO THIS EVE UNDER DEPARTING MSLP GRADIENT SO HAVE ADVISORY GOING TO MIDNIGHT IN THAT AREA. AIR TEMPS WILL BE VERY COLD TONIGHT AS THE ARCTIC HIGH OF 1040MB MAGNITUDE MOVES OVER THE SRN CWA. DIMINISHING WIND SPEEDS IN MN...CLEAR SKIES CWA WIDE...AND FRESH SNOW COVER IN MANY PLACES WILL RESULT IN AN IDEAL SETUP FOR PLUNGING TEMPS BETWEEN 7 PM AND 9 PM. NEGATIVE DOUBLE DIGITS LIKELY TO PREVAIL ACROSS MUCH OF THE MN CWA BY 9 PM. FRESH SNOW COVER EXPECTED TO HAVE A SEVERAL DEGREE IMPACT. RECENT LOCAL CLIMATOLOGICAL RESEARCH WITH A NIGHT AFTER A FRESH SNOW AND THESE SIMILAR SYNOPTIC CONDITIONS WOULD INDICATE NEAR -18F AT MSP. HAVE GONE JUST SLIGHTLY ABOVE THAT WITH SOME CIRRUS/CIRROSTRATUS EXPECTED VERY LATE. AREAS OF WEST CTRL MN WITH DEEP FRESH SNOW ARE EXPECTED TO DROP TO -23 TO -28. RECORD LOW MIN TEMP AT ST CLOUD FOR TUES MORNING IS -21 IN 1963 WHICH WILL BE IN GREAT JEOPARDY. ON THE IMMEDIATE HEALS OF THIS ARCTIC HIGH WILL COME A POTENT MID- LEVEL SHORT WAVE RIDING NORTHEAST WITHIN THE POWERFUL STATIONARY UPPER LEVEL JET TO OUR SOUTH ON TUES AND TUES NIGHT. VORT ADVECTION AND MID-LEVEL WARM AIR ADVECTION IS STRONG AND FOCUSED AHEAD OF THIS. THE 00Z AND 06Z NAM HAVE BEEN A BIT MORE POTENT WITH THIS...BUT BOTH THESE...THE 00Z GFS...AND 21Z SREF FAVOR AT LEAST SRN MN TO WRN WI TO BE UNDER A CORRIDOR OF SNOW DURING TUES AFTN AND EVE. WITH THE SNOW FALLING INTO A VERY COLD AIR MASS...RATIOS ARE LIKELY TO BE AT LEAST 17:1 IF NOT CONSIDERABLY HIGHER. FORECAST SNOWFALL TOTALS OF 2 TO 4 INCHES RIGHT NOW WOULD WARRANT AN ADVISORY AS TIME APPROACHES AND THE IMMEDIATE WIND CHILL CONCERNS END. THIS WILL HAVE TO BE WATCHED CLOSELY...AS FAVORABLE QUADRANT FOR STATIONARY BANDING MAY ENTER THE CWA AND INCREASE THOSE SNOWFALL AMOUNTS FROM ALBERT LEA...TO RED WING...TO EAU CLAIRE. ALSO POSSIBLE THAT ADVISORY AMOUNTS MAY NEED TO BE EXTENDED NORTHWARD TOWARDS THE TWIN CITIES...BUT AT THIS TIME UNCERTAINTIES REMAIN. ONE OF THOSE IS A WAVE ON THE POLAR JET TO OUR NORTH WHICH DOES MOVE IN DURING THE EVE. THE INFLUENCE THIS HAS ON THE SRN SHORT WAVE MAY ENHANCE AMOUNTS FURTHER NORTH DURING THE LATE AFTN AND EVE. HAVE FORECASTED SNOWFALL AMOUNTS RIGHT NOW IN THE ENVELOPE OF MOST CONFIDENCE WHICH CONTINUES TO INCREASE. AFTER THAT...A SYSTEM ON THU IN THE MIDDLE OF THE COUNTRY POTENTIALLY KEEPS OUR ONE SYSTEM-EVERY-36-HOUR PATTERN GOING STRONG. THIS SYSTEM IS THE BULK OF THE ENERGY OF THE NOW CLOSED LOW DROPPING SOUTHWARD OFF THE PACIFIC COAST THIS MORNING. MODELS HANDLE THIS CONSISTENTLY THROUGH THE FIRST 48 HOURS BUT THEN DIVERGE MID-WEEK IN THE RESPONSIVE LEE-CYCLOGENESIS. 00Z GFS WAS AN OUTLIER...BRINGING A LOW ON A VERY INTERESTING PATH FAVORING GOOD SNOW HERE. 00Z ECMWF ON THE OTHER HAND IS THE FURTHEST SOUTH BRINGING THE LOW INTO SRN IL AND GIVING US BASICALLY NOTHING. ENSEMBLE LEANS TOWARDS THE ECMWF WHICH HAS BEEN CONSISTENT AT KEEPING THE MAJORITY OF THE THE PRECIP FROM THIS SYSTEM TO OUR SOUTH. WILL HAVE TO WATCH CLOSELY BUT TOUGH AT THIS POINT TO GET A GOOD HANDLE ON THE GUIDANCE WITH THAT SYSTEM. HAVE GENERALLY KEPT THINGS AS IS WITH THE FORECAST DURING THU. OVERALL...BELOW NORMAL TEMPS TO PREVAIL THROUGH THE WEEK WITH ANOTHER COLD SHOT OF A POTENTIAL SIMILAR MAGNITUDE AS THIS CURRENT ONE BECOMING MORE LIKELY NEXT WEEKEND. && .AVIATION.../18Z TAF ISSUANCE/ SKY COVERAGE DECREASING EARLY THIS AFTERNOON BUT WEST-NORTHWEST WINDS REMAIN FAIRLY STRONG WITH 10 TO 15 KTS SUSTAINED AND GUSTS OF 20 TO 25 KTS CONTINUING. THESE WINDS WILL BEGIN TO DECREASE FROM WEST TO EAST LATE THIS AFTERNOON. SKIES WILL BE GENERALLY SCATTERED BETWEEN 1500 AND 2500 FT WITH A FEW BROKEN PERIODS IN SPOTS...ESPECIALLY ACROSS EAST CENT MN AND WEST CENT WI THROUGH MID AFTERNOON. CLEAR SKIES WILL BE FOUND THIS EVENING BEFORE HIGH CLOUDS RETURN TONIGHT. WINDS TONIGHT WILL DECREASE TO 6 KTS OR LESS AS HIGH PRESSURE WORKS IN. WINDS WILL SHIFT AROUND TO THE SOUTH OVERNIGHT FROM WEST TO EAST WITH SPEEDS INCREASING TO 6 TO 10 KTS ACROSS WEST CENT MN BY EARLY MORNING AND THE REMAINING AREAS THROUGH EARLY AFTERNOON. MID LEVEL CEILINGS WILL LOWER THROUGH THE MORNING AS A LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTHWEST. SNOW IS EXPECTED AT ALL SITES BY TUESDAY AFTERNOON. STILL A FEW MODEL DISCREPANCIES WITH NORTHWEST EXTENT OF BETTER SNOWFALL BUT PREVIOUS FORECAST THINKING OF KRWF/KMSP/KEAU/KRNH SEEING 2 TO 3 INCHES LOOKS ON TRACK...WITH LESSER AMOUNTS AT KSTC/KAXN. SNOW SHOULD START AT KRWF DURING THE MORNING AND EXPAND NORTHEASTWARD TO KMSP/KRNH/KEAU BY MIDDAY. EXPECT MOSTLY LOW END MVFR CEILINGS AND VISIBILITIES IN THE SNOW BUT PERIODS OF CEILINGS OF LESS THAN 1000 FT AND BETWEEN 1 AND 2 SM ARE LOOKING POSSIBLE AT KRWF/KMSP/KRNH/KEAU DURING THE AFTERNOON IN HEAVIER SNOW BANDS. SYSTEM WILL QUICKLY EXIT THE SITES BY EARLY/MID EVENING. THANKS TO CWSU ZMP FOR THE COORDINATION. ZMP FORECAST THOUGHTS INCLUDED BELOW... FROM CWSU ZMP...SYNOPTICALLY WE HAVE AN OCLDD LOW CENTERED N OF LAKE HURON AND A COLD FNTL BNDRY STRETCHING S THRU OH/KY/W TN/SE AR/E TX. HI PRES IS RDGG INTO WRN ZMP. THRU TOMORROW THE RDG SHIFT RAPIDLY INTO ERN ZMP, ALLOWING A DISTURBANCE TO MOV IN UNDER THE RDG AND INTO IA/SRN MN BY THE END OF THE FCST PERIOD. NAM/GFS/MM5 REACHING SIMILAR SOLUTIONS (FINALLY!), WITH NAM LAGGING BEHIND THE OTHER TWO SLIGHTLY WHEN IT COMES TO THE ARRIVAL OF THE NEXT SYS. START THE TAF WITH SCT018, THEN GO SKC AFT 00Z. WE SHOULD BE SCT200 BY 10Z, AND SCT120 BKN200 BY 12Z. BY 15Z GO BKN100, THEN DROP TO SCT020 BKN030 BY 18Z. OVC015-020 SHOULD OCCUR BY 21Z AND PERSIST THRU THE WORSE PART OF THE STORM THRU 03Z. AFT THAT WE MIGHT EVEN SCT OUT AT THE 020 AND 050 LVLS. SNOW SHOULD START AROUND 17Z AND END AT 02Z. ACCUM SHOULD BE 2-3 INCHES. VIS SHOULD STAY AT 3SM OR GREATER AS BLSN WON`T HAPPEN WITH THE XPCTD WND SPDS AND LOW ABSOLUTE HUM PROG SHOWS ADDITION OF BR UNLIKELY. WNDS WILL BE 280-290 THRU 00Z, THEN GRADUALLY BECOME SOUTHERLY BY 12Z AND SSE-LY BY 00Z. WND SPDS WILL STEADILY DROP THRU 12Z, WHEN THEY`LL BE AT 5 KTS, THEN INCRS SLIGHTLY TO 10KT BY 21Z. AFT 21Z THEY GRADUALLY DROP AGAIN TO <5KTS BY THE END OF THE FCST PERIOD. ...MDB/PDP.. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ANOKA- BENTON-BLUE EARTH-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN- GOODHUE-HENNEPIN-ISANTI-KANABEC-LE SUEUR-MCLEOD-MEEKER- MILLE LACS-MORRISON-NICOLLET-RAMSEY-RICE-SCOTT-SHERBURNE- SIBLEY-STEARNS-STEELE-WASECA-WASHINGTON-WRIGHT. WIND CHILL WARNING UNTIL 6 PM CST THIS AFTERNOON FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MARTIN-POPE- REDWOOD-RENVILLE-STEVENS-SWIFT-TODD-WATONWAN-YELLOW MEDICINE. WI...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BARRON- CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. && $$ MTF/MDB/PDP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 414 PM CST MON DEC 15 2008 .SHORT TERM...TONIGHT THROUGH 12Z WEDNESDAY. MAIN CONCERN IS SNOW AMOUNTS WITH QUICK MOVING SYSTEM TO IMPACT THE AREA LATE TONIGHT INTO TUESDAY. AFTER A BITTERLY COLD START TO THE MORNING...TEMPERATURES HAVE STRUGGLED TO WARM INTO THE SINGLE DIGITS ACROSS NE ZONES WITH A FEW SITES MAKING IT INTO THE LOWER DOUBLE DIGITS IN NORTH CENTRAL KS. SURFACE ANALYSIS SHOWS 1042 MB ARCTIC SURFACE HIGH CURRENTLY CENTERED OVER NORTH CENTRAL TO EASTERN NE. LATEST WATER VAPOR IMAGERY SHOWS UPPER LOW SPINNING OVER THE SOUTHERN OR/NORTHERN CA COAST...WITH RUC UPPER AIR ANALYSIS DATA SHOWING NOSE OF 140 KT UPPER JET STREAK COMING INTO SOUTHERN CA AND A FEW LIGHTNING STRIKES ASSOCIATED WITH THE DYNAMICS OF THIS FEATURE. MID AND HIGH LEVEL CLOUDS CURRENTLY ON THE INCREASE FROM THE SOUTHWEST AHEAD OF THIS FEATURE. THE SURFACE HIGH WILL SLIDE EAST TONIGHT...WITH ISENTROPIC LIFT IN THE 285-290K LAYER INCREASING AS RETURN FLOW DEVELOPS AROUND THE HIGH. MEANWHILE THE AFOREMENTIONED H3 JET STREAK COMING INTO SOUTHERN CA WILL CONTINUE TO WORK NORTHEAST...WITH THE LEFT EXIT REGION OF THIS FEATURE MOVING INTO THE CWA FROM THE SOUTHWEST BETWEEN 06Z AND 12Z /ALONG WITH SOME MID-LEVEL SHORTWAVE ENERGY/. THIS WILL NOT ONLY PROVIDE ENHANCED PURELY DYNAMICAL LIFT PER THE DIVERGENCE ALOFT...BUT ALSO GENERATE SOME ENHANCED MID-LEVEL FRONTOGENETICAL FORCING MOST EVIDENT IN THE H7-H6 LAYER. THE LOWER BRANCH OF THE INDIRECT CIRCULATION IN THE EXIT REGION ALSO ENHANCES THE ISENTROPIC LIFT...WITH THIS ENHANCED FORCING ALL IMPACTING THE CWA FROM ROUGHLY 06Z TONIGHT TO 18-21Z TUESDAY. THINK ALL OF THE CWA WILL SEE SOME MEASURABLE SNOW...BUT THE TOUGHEST PART IS NAILING DOWN AMOUNTS. THE EASTERN CWA LOOKS TO BE MOST FAVORED FOR THE HEAVIER AMOUNTS...WITH LESSER AMOUNTS AS YOU WORK WEST. QPF AMOUNTS WILL BE LIGHT GIVEN THE ARCTIC AIRMASS IN PLACE...BUT SNOW TO LIQUID RATIOS WILL BE HIGH. USED A 15-20:1 RATIO IN LINE WITH COBB DATA WHICH RESULTS IN TOTAL ACCUMULATIONS OF AROUND 1 INCH IN THE SOUTHWEST TO 3-4 INCHES IN THE EAST. HAVE HOISTED A WINTER WEATHER ADVISORY FOR AREAS GENERALLY EAST OF HIGHWAY 281 WHERE ACCUMULATIONS OF 2-4 INCHES ARE FORECAST. THE SNOW WILL BE VERY LIGHT AND POWDERY GIVEN THE VERY COLD AIRMASS IN PLACE...BUT WINDS WILL BE LIGHT AND THUS BLOWING/DRIFTING SHOULDN/T BE MUCH OF A PROBLEM. THE SNOW TAPERS OFF FROM WEST TO EAST TUESDAY AFTERNOON...WITH DRY CONDITIONS ANTICIPATED BY EARLY EVENING. THE OTHER CONCERN TONIGHT IS COLD WIND CHILLS ONCE AGAIN...ALTHOUGH NOT NEARLY AS COLD AS LAST NIGHT/THIS MORNING. WIND CHILLS WILL RANGE FROM AROUND 10 BELOW IN THE SOUTH TO 20 BELOW ZERO IN THE NORTH LATE TONIGHT/EARLY TUESDAY MORNING. WILL HOLD OFF ON ANY WIND CHILL HEADLINES GIVEN MARGINAL APPARENT TEMPS AND ALSO MARGINAL WINDS WHICH WILL BE RIGHT AROUND THE 10 MPH THRESHOLD IN THE NORTH WHERE THE COLDEST TEMPS ARE EXPECTED. COLD TEMPERATURES CONTINUE ON MONDAY WITH HIGHS EXPECTED TO BE SLIGHTLY WARMER THAN TODAY BUT STILL VERY COLD AS H85 TEMPS REMAIN ROUGHLY 5 TO 15 DEGREES BELOW ZERO. SINGLE DIGIT TEMPS ABOVE AND BELOW ZERO THEN IN STORE AGAIN TUESDAY NIGHT FOR LOWS. .LONG TERM...12Z WEDNESDAY THROUGH MONDAY. MAIN FORECAST CONCERNS LIE WITH TEMPERATURES...AND WITH PRECIPITATION CHANCES MID WEEK AND FIRST PART OF THE WEEKEND. EXTENDED PERIOD STARTS OFF QUIET AND DRY...AS LATEST SYSTEM HAS MOVED OFF WELL TO THE EAST. IN THE UPPER LEVELS...MODELS ARE IN GOOD AGREEMENT SHOWING ZONAL/SLIGHT SOUTHWESTERLY FLOW ACROSS THE REGION WITH A LOW PRESSURE SYSTEM SITTING NEAR THE COAST OF CA. AT THE SURFACE...HIGH PRESSURE DOMINATES THE AREA IN THE MORNING...THEN GRADUALLY SLIDES TO THE EAST THROUGH THE REST OF THE DAY. AS IT SLIDES EAST...SO DOES THE COLDEST AIR. AND WHILE STILL CHILLY AND BELOW NORMAL...HIGHS WILL FEEL BETTER...ESP ACROSS NORTHERN PORTIONS OF THE CWA...AS THEY REACH INTO THE MID TEENS NORTH/LOWER 20S SOUTH. THINGS BECOME MORE INTERESTING DURING THE WED NIGHT/THURSDAY PERIOD...AND WILL STATE RIGHT OFF THAT CONFIDENCE IN THIS TIMEFRAME AND BEYOND IS LOW. ONE ASPECT THAT THERE IS A BIT MORE CERTAINTY WITH IS THAT THE UPPER LEVEL SYSTEM WHICH WAS OF THE COAST OF CA GETS KICKED OUT INTO THE ROCKIES AS A STRONGER TROUGH MOVES INTO THE PAC NW REGION. BUT THE TIMING...STRENGTH...PATH...AND ASSOCIATED PRECIP AND PRECIP TYPE AS IT MOVES THROUGH ALL CONTINUE TO HAVE PLENTY OF QUESTIONS. FORECAST IS A BLEND...AS SOME GUIDANCE SHOWS A MORE OPEN...QUICKER UPPER LEVEL SYSTEM...VS OTHERS WHICH REMAINS CLOSED OFF A BIT LONGER AND THUS SLOWER. HAVE PRECIP CHANCES MOVING IN STARTING LATE WEDNESDAY NIGHT FROM SOUTH TO NORTH...AS LIFT AHEAD OF THE SYSTEM INCREASES...AIDED BY A 140+KT JET STREAK NOSING INTO THE REGION. HAVE BEST CHANCES FOR PRECIP COMING DURING THE DAYTIME HOURS ON THURSDAY BEFORE TAPERING OFF...BUT SOME MODELS HAVE STARTED TO TREND EVEN SLOWER...SHOWING PRECIP LINGERING AROUND INTO THE OVERNIGHT HOURS THURSDAY. WOULD LIKE TO SEE MORE MODEL AGREEMENT BEFORE MAKING SIGNIFICANT TIMING CHANGES. ANOTHER AREA OF CONCERN WITH THIS SYSTEM IS WITH PRECIPITATION TYPE. THERE REMAINS QUESTIONS WITH THE TIMING/LOCATION OF THE SURFACE LOW...WHICH BY THURSDAY EVENING RANGES ANYWHERE FROM A SLOWER/SOUTHWESTERN KS SOLUTION TO A FASTER/NC NEB SOLUTION. MODELS DO AGREE THAT WARMER LOWER LEVEL AIR JUST OFF THE SURFACE GETS PULLED NORTH THANKS TO INCREASED SOUTHERLY FLOW...WHICH PRESENTS AN ISSUE WITH PRECIP TYPE...BUT QUESTIONS EXIST WITH HOW FAR NORTH THIS WARMER AIR GETS. INTRODUCED MENTION OF FREEZING RAIN ACROSS OUR KS COUNTIES...WHICH LOOKS TO HAVE THE BEST CHANCE...AT THIS POINT...TO SEE VARYING PRECIP TYPES. KEPT MENTION OF ALL SNOW TO THE NORTH. STILL A LOT OF DETAILS TO BE WORKED OUT WITH THIS SYSTEM OVER THE UPCOMING SHIFTS. KEPT FRIDAY DRY...AS THE REGION SITS IN BETWEEN SYSTEMS. YET ANOTHER DAY OF BELOW NORMAL TEMPERATURES...WITH HIGHS REACHING INTO THE LOWER 20S NORTH/NEAR 30 SOUTH. ANOTHER BLAST OF COLD ARCTIC AIR EXPECTED TO IMPACT THE CWA THIS WEEKEND...AS ANOTHER UPPER LEVEL SYSTEM MOVES IN FROM THE WEST. THIS IS ANOTHER QUICK MOVING SYSTEM...WHICH PUSHES A SFC COLD FRONT THROUGH BY SAT MORNING. HIGH PRESSURE AND COLDER AIR QUICK TO BUILD IN BEHIND THE FRONT...DROPPING HIGHS FOR THIS WEEKEND ONCE AGAIN BACK INTO THE SINGLE DIGITS ACROSS THE NORTH...WITH MID TEENS SOUTH. AT THIS POINT...PRECIP LOOKS TO BE ALL SNOW...AND NOT SIGNIFICANT IN REGARD TO AMOUNTS. MONDAY EXPECTED TO REMAIN COLD AS CWA REMAINS UNDER THE INFLUENCE OF THE SFC HIGH...WITH HIGHS IN THE LOWER/MID TEENS. && .AVIATION...18Z TAF. NORTHWEST WINDS TO START THE PERIOD WILL STEADILY WEAKEN AND VEER TO THE NORTHEAST THIS AFTERNOON INTO EARLY EVENING AROUND SURFACE HIGH. CLEAR SKIES EXPECTED INTO THE EARLY EVENING BEFORE SOME MID CLOUDS BEGIN TO STREAM IN AHEAD OF NEXT FAST MOVING STORM SYSTEM. VFR CONDITIONS EXPECTED UNTIL AFTER MIDNIGHT BEFORE LOWER CIGS...REDUCED VISIBILITIES...AND SNOW MOVE IN AROUND 08-09Z. SNOW WILL THEN LIKELY CONTINUE THROUGH THE REST OF THE PERIOD...WITH SOME ACCUMULATIONS OF 1 TO 3 INCHES POSSIBLE BY TUESDAY AFTERNOON. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST TUESDAY FOR NEZ041-048-049-063-064-076-077-086-087. KS...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST TUESDAY FOR KSZ007-019. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1133 AM EST MON DEC 15 2008 .SYNOPSIS... MUCH COLDER AIR WILL SPREAD ACROSS THE REGION THIS AFTERNOON IN WAKE OF A COLD FRONT. THE FRONT WILL STALL SOUTH OF THE OHIO VALLEY TONIGHT. AN UPPER LEVEL DISTURBANCE WILL BRING A SHOT OR PRECIPITATION TONIGHT...BEFORE A WAVE OF LOW PRESSURE RIDES UP THE FRONT TUESDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BUSY MRNG CONTINUES ON THE FCST DESK. SECOND MRNG UPDATE AS FRNTL BNDRY HAS NOW CLEARED EASTERN FCST AREA BORDER. TEMPS HAVE PLUMMETED ALL MRNG...WITH MUCH OF THE AREA NORTHWEST OF A CINCY- SPRINGFIELD- MARION LINE NOW NEAR OR BELOW FREEZING. MUCH OF THE HEAVIER PCPN REMAINS IN WARM ENUF BNDRY LYR THAT IT IS FALLING AS RAIN...AND IS NOW LARGELY CONFINED TO ERN 1/3 FCST AREA. PCPN MUCH MORE SPOTTY BEHIND MAIN PCPN AREA...BUT ARCTIC AIR HAS RUSHED IN SO QUICKLY THAT MUCH OF THIS IS MOST LIKELY FALLING AS SOME FORM OF A WINTRY MIX (-FZRA/PL). WHILE PCPN WILL NOT BE A SIGNIFICANT PROBLEM THIS AFTN...STILL CONTEST THAT RAPIDITY TO TEMP DROP COULD CREATE SOME PROBS ON ROADS/EXPOSED SURFACES FOR FLASH FREEZING. THEREFORE...CHANGES TO HEADLINES THAT WERE INITIATED THIS MRNG WILL CONTINUE FOR THE AFTN (SEE NEXT PARAGRAPH FOR MORE INFO ON THAT). CONTINUE TO LIKE HOW RUC IS HANDLING THE TEMP FALLS THIS MRNG AND HAVE LEANED HEAVILY ON IT FOR HOW FAR TEMPS BOTTOM OUT BY LATE AFTN. DESPITE MORE AGGRESSIVE TEMP DROP FOR THE AFTN FCST...SHOULD TEMPS FALL FASTER THAN FCST (AND ENTIRELY POSSIBLY THAT THEY DO WITH CURRENT TEMPS OVER CNTRL INDIANA AROUND 20 DEG). HAVE READJUSTED GRIDS FOR AFTN HOURS...AND THAT REQUIRED TEMP ADJUSTMENTS INTO THE EVNG AS WELL. QUICK GLANCE AT 12Z MODELS SHWNG PLENTY OF VARIABILITY OVER NEXT 48 HOURS...INCLUDING DIFFERENCES IN SNOWFALL AMOUNTS OVER SE 1/2 FCST AREA TONIGHT (NAM MORE ROBUST...GFS WOULD SUGGEST LESS SNOW). WHAT HAPPENS TONIGHT WILL HAVE AN IMPACT ON SECOND WAVE TO AFFECT REGION TUES NIGHT. AS STATED ABV...NO CHANGES ATTM TO WINTER WX ADV LOCATION AND TIMING OVERNIGHT. MODELS DO AGREE ON A SLOWER ONSET TO ANY DEFORMATION FORCED PCPN OVERNIGHT...WITH SIGNIFICANT WINTRY PCPN HAVING GREATEST IMPACT BTWN MIDNIGHT AND MID MRNG TUES. 12Z OP GFS APPEARS TO SHOW ARCTIC AIRMASS WINNING OUT AND SUPPRESSING PCPN TO SOME EXTENT AS A RESULT. WILL BE LOOKING AT THIS IN MUCH GREATER DETAIL FOR AFTN FCST PACKAGE. ADVISORY INFO FOR AFTN (FROM 854 AM DISCUSSION)...OF MUCH GREATER CONCERN IS THE POTENTIAL FOR A FLASH FREEZE ON ROADS/EXPOSED SURFACES DUE TO THE SIGNIFICANT NATURE OF THE TEMP FALLS. ESSENTIALLY...THE TEMPERATURE WILL FALL SO QUICKLY THAT WATER ON THE ROADS AND EXPOSED SURFACES STAND A GREATER CHANCE TO FREEZE RAPIDLY CAUSING POTENTIAL FOR BLACK ICE AND SLICK ROADS. INTEND TO HANDLE THIS WITH A WINTER WX ADVISORY AND EXTEND IT OUT FOR THE ENTIRE AREA...BEGINNING IMMEDIATELY ACRS NW 1/2 FCST AREA AND BY 16Z FURTHER TO THE SOUTHEAST. IN AN EFFORT TO KEEP THINGS SIMPLE AND NOT CONFUSE THE PUBLIC...FELT BEST COURSE OF ACTION WAS TO MERGE THE ADVISORIES WE HAD UP FOR THIS MRNG ACRS WEST CNTRL OH AND TONIGHT ALONG AND SOUTH OF I-71 INTO ONE PRODUCT WITH TWO SEGMENTS. THE ADVISORY FOR WINTRY PCPN TONIGHT WILL NOW BEGIN AT 16Z TO ACCOUNT FOR POTENTIAL FLASH FREEZING CONDITIONS THIS AFTN. THE ADVISORY WILL THEN CONTINUE IN ITS PREV STATE TONIGHT FOR THE EXPECTED WINTRY PCPN. THE REMAINDER OF THE FCST AREA TO THE NORTHWEST OF I-71 WILL HAVE AN ADVISORY FOR FLASH FREEZE POTENTIAL NOW THRU 22Z. ZONE AND GRID UPDATES OUT SHORTLY. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... MODELS EJECT A H/5 VORT OUT TONIGHT. THIS CAUSES A DEFORMATION BEND TO DEVELOP ACRS THE SRN PORTION OF THE FA TONIGHT...RUNNING ALONG A SDF-CVG-CHILLICOTHE LINE.THICKNESSES SHOULD COLD ENUF FOR SNOW...EXCEPT IN KY...WHERE SOME PL IS POSSIBLE. MODELS ARE SHOWING SLIGHT DIFFERENCES...MAINLY IN THE AMOUNT OF QPF PRODUCED. THE NAM IS DRIER...ESPECIALLY IN THE NW COUNTIES..WHILE THE NGM AND ECMWF ARE MUCH WETTER. THE GFS LOOKS TO BE A NICE COMPROMISE...SO LEANED TOWARDS IS SNOW AND QPF. WENT WITH A 2-4 INCH SNOW SWATH SURROUNDED BY A 1-3. WENT A WINTER WX ADVISORY FOR THE SRN 2/3 OF FA. THAT ENERGY SLIDES NE OF THE REGION FOR TUE. THERE IS STILL SOME LINGERING OVERRUNNING LIFT...ESPECIALLY IN THE S ON TUE...BUT ONLY LIGHT PCPN AMOUNT S EXPECTED. THEN NEXT AND STRONGER H5 VORT KICKS OUT OF THE MS VALLEY TUE NIGHT...CAUSING A SFC LOW TO DEVELOP. WITH ARCTIC AIR IN PLACE...SFC TEMPS WILL BE BELOW FREEZING. HOWEVER H8 TEMPS WILL RISE QUICKLY ABOVE 0 C AND WITH GOOD ISENTROPIC LIFT. NAM AND GFS ARE SIMILAR WITH THE OVERALL FEATURES...WITH THE GFS A LITTLE DEEPER WITH THE LOW. LEANED TOWARDS THE GFS...SO LOOKS LIKE A PERIOD OF FZRA UNTIL SFC TEMPS WARM ABOVE FREEZING. THE NW WILL PROBABLY SEE SOME SNOW AT THE ONSET...SINCE THE COLD AIR IS DEEPER UP THERE. THERE IS ENUF THREAT TO ISSUE A WINTER STORM WATCH FOR TUE NGT. LOW PASSES TO THE E LATE TUE NGT INTO WED. LOOKS LIKE THERE WILL BE SOME LINGERING PCPN EARLY WED....BUT IT SHOULD END BY NOON. GFS TRIES TO DEVELOP ANOTHER LOW IN THE PLAINS WITH A WRMFNT IN THE OH VLY. THE OLD ECMWF WASNT AS STRONG...SO DISCOUNT THE 00Z GFS FOR WED NGT. GENERALLY WENT CLOSE TO MAV...SINCE LEANED TOWARDS THE GFS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ACTIVE WEATHER PATTERN THROUGH THE EXTENDED FORECAST PERIOD. HAVE TRENDED THE FORECAST SOLN CLOSER TO OPERATIONAL ECMWF WITH A HIGH DEGREE OF UNCERTAINTY REGARDING EXACT TIMING OF INDIVIDUAL WX SYSTEMS. UPPER LEVEL FLOW BACKS WITH A DEEPENING LOW EJECTING NE FROM THE CENTRAL PLAINS ON THURSDAY INTO THE OHIO VALLEY THURSDAY NIGHT. MODEL DIFFERENCES ON THE TIMING AND LOCATION OF THIS LOW. THE GFS IS QUICKER AND FURTHER N WITH THE LOW. HAVE FOLLOWED THE COLDER AND SLOWER ECMWF SOLN BUT OPTED FOR A LTL QUICKER RETURN OF MOISTURE. HAVE SPREAD OVERRUNNING PRECIP BACK NORTH LATE WED NIGHT INTO THURSDAY. THIS PRECIP WL LIKELY BEGIN AS A WINTRY MIX BEFORE CHANGING OVER TO RAIN AS WARMER AIR ADVECTS IN LATE THUR NIGHT AND EARLY FRI PRIOR TO FRONTAL PASSAGE. SURFACE HI TO PROVIDE DRY WEATHER FRIDAY NIGHT INTO SATURDAY. ARCTIC FRONT LOOKS TO PASS THRU LATE SATURDAY WITH COLD TEMPS AND DRY WX EXPECTED NEXT SUNDAY. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... WIDESPREAD RAIN AHEAD OF AND BEHIND FRONTAL PASSAGE WILL BRING VSBYS TO MVFR CONDITIONS AT TIMES THIS MORNING. FROPA WILL BE ON THE WESTERN TAF SITES BORDER AT 12Z AND WORK QUICKLY EAST...THROUGH CMH AND ILN BY 1330Z THIS MORNING. RAIN WILL HANG ON FOR A BIT BEHIND FROPA BUT SFC TEMPS WILL DROP TO BELOW FREEZING FOR A FEW HOURS BEFORE PRECIP ENDS. CIGS WILL DROP TO THE MVFR CATEGORY THIS MORNING AND AFTERNOON BUT SEE A FEW UPWARD PEEKS WHERE THE LOW SC DECK IS OCCASIONALLY SCT UNDER A BKN 6-10KFT DECK. WEST WIND SHIFT WILL ANNOTATE FROPA THIS MORNING. BY EVENING...AN UPPER VORT WILL WRING OUT SOME SNOW ALONG AND ESP SE OF I-71 CORRIDOR. AM NOT ENTIRELY CERTAIN WHERE THE BACK EDGE OF THIS SNOW IS BUT ENOUGH DRY AIR AT THE MID LEVELS COULD ALLOW LOWER SC DECK FROM 1-2KFT TO BREAK UP AT TIMES OVERNIGHT...ESP TO THE NW. OUTLOOK...MVFR CIGS/VSBYS POSSIBLE THROUGH WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR OHZ026-034-035-042>046-051>053-060-061. WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR OHZ026-034-035-042>046-051>056-060>065-070>074- 077>082-088. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR OHZ054>056- 062>065-070>074-077>082-088. KY...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR KYZ089>100. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR INZ050-058-059-066. WINTER STORM WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT FOR INZ050-058-059-066-073>075-080. WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR INZ073>075- 080. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...SITES LONG TERM...AR AVIATION...FRANKS oh