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 ALBANY NY 1243 AM EST FRI DEC 12 2008 .SYNOPSIS... A COMPLEX WINTER STORM SYSTEM WILL MOVE NORTHEAST ALONG THE MID ATLANTIC REGION OVERNIGHT. THIS STORM WILL BE NEAR THE SOUTHERN NEW ENGLAND COAST FRIDAY MORNING. A WINTRY MIX OF PRECIPITATION WILL CONTINUE ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND THROUGH FRIDAY MORNING...WITH SIGNIFICANT ICE ACCUMULATIONS FROM THE CAPITAL REGION SOUTH AND EAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTHERN GREAT LAKES REGION FRIDAY NIGHT WITH COLD AND DRY WEATHER TO OPEN THE WEEKEND. && .NEAR TERM /THROUGH FRIDAY/... ...MESOSCALE UPDATE ON THE STORM... SIGNIFICANT WINTER STORM CONTINUES TO IMPACT THE REGION THIS EVENING WITH A VARIETY OF PCPN TYPES. THE 00Z RUC HAS THE SFC LOW /1000 HPA/ JUST W/NW OF KGSO WITH A THERMAL TROUGH/WARM FRONT EXTENDING NORTHEAST FROM THE MID ATLANTIC REGION INTO THE NORTHEAST WITH TREMENDOUS OVER RUNNING OCCURRING ALONG THE LOW LEVEL BAROCLINIC ZONE. WE ARE EXPECTING PCPN RATES TO BE WIDESPREAD IN THE ONE TO TWO TENTHS ON AN INCH HOUR RANGE BASED ON THE OBSERVATIONS FROM NRN NJ...ERN PA...AND LONG ISLAND OVER THE NEXT SEVERAL HOURS. KTTN IS COMING IN CLOSE TO A QUARTER AN INCH AN HOUR AT THIS HOUR. A TROPICAL CONNECTION OF MOISTURE IS ONGOING WITH THE ANOMALOUS SOUTHERLY LOW-LEVEL JET /50-60 KTS!/ TAPPING INTO THE ANOMALOUS PRECIPITABLE WATER AIR FROM THE GULF STREAM AND GULF OF MEXICO. STRONG LOW TO MID LEVEL FRONTOGENESIS WILL PERSIST PRIOR TO 1200 UTC/FRI FROM THE CAPITAL REGION SOUTH AND EAST KEEP THE PCPN RATES INTENSE. THE 00Z KALY SOUNDING IS IN SHOWING A TREND TO FREEZING RAIN WITH THE SUBFREEZING LAYER ONLY FROM THE SFC TO ABOUT 900 HPA. THE WARM NOSE ISN/T SUPER IMPRESSIVE...BUT WITH TEMPS ABOVE FREEZING FROM /PEAKING ABOUT +2C/ 900 HPA TO 750 HPA. GROUND TRUTH FROM NORTH OF THE CAPITAL REGION HAS BEEN MOSTLY SLEET AND SNOW WITH A FEW INCHES OF ACCUMULATION. A TRANSITION TO ALL FREEZING RAIN HAS OCCURRED IN MOST OF THE CAPITAL REGION...PORTIONS OF SOUTHERN VT AND THE BERKSHIRES...WE EVEN HAVE SOME TEMPS ABOVE FREEZING WITH PLAIN RAIN...IN THE BERKS...AND PARTS OF RENSSELAER COUNTY WITH DOWN SLOPING. LOCATIONS SOUTH OF THE CAPITAL REGION CONTINUE TO BE MAINLY FREEZING RAIN...WITH POSSIBLE POCKETS OF RAIN WITH TEMPS GETTING ABOVE 32 DEGREES. THE TREND WILL BE FOR THE MID HUDSON VALLEY TO HEAD ABOVE FREEZING PRIOR TO MIDNIGHT. ICE ACCRETIONS OF TWO TO FOUR TENTHS OF AN INCH HAVE BEEN REPORTED THUS FAR...MAINLY FROM THE CAPITAL REGION SOUTH AND EAST. WE WILL BE ISSUING AN UPDATE TO REMOVE SNOW FROM THE CAPITAL REGION...BERKSHIRES...CNTRL MOHAWK VALLEY SOUTH. WE WILL KEEP SLEET IN PRIOR TO MIDNIGHT BASED ON THE LATEST RADAR AND OBSERVATIONAL TRENDS...AND A CHANCE OF SLEET AFTER MIDNIGHT. ICE ACCUMULATIONS OF A HALF AN INCH TO AN INCH LOOK LIKELY FROM THE CAPITAL REGION...SOUTHERN VERMONT...AND CNTRL MOHAWK VALLEY SOUTH. NUMEROUS REPORTS OF POWER OUTAGES /DUE TO TREES...TREE LIMBS AND WIRES DOWN/ ARE COMING IN FROM THE MID HUDSON VALLEY...BERKSHIRES...AND THE ERN CATSKILLS SOUTH. TEMPS SHOULD RISE ABOVE FREEZING IN THE MID HUDSON VALLEY/SRN TACONICS AFTER MIDNIGHT WITH PLAIN RAIN. WE ACCOUNTED FOR THIS IN THE GRIDS. LOCATIONS NORTH AND WEST OF THE CAPITAL REGION ENTRENCHED IN THE COLDER AIR...WILL SEE SNOW RATES UP TO AN INCH AN HOUR...WITH SLEET. PORTIONS OF THE SRN ADIRONDACKS COULD RECEIVE SIX TO TWELVE INCHES OF SNOW. EXPECT SIGNIFICANT SLEET ACCUMULATIONS IN THE LAKE GEORGE REGION. PLEASE SEE OUR LATEST PUBLIC INFORMATION STATEMENT...WITH SNOW...SLEET...AND ICE AMOUNTS. ALSO SEE OUR LOCAL STORM REPORT WITH THE POWER OUTAGES AND DAMAGE. HEADLINES WILL REMAIN AS IS...ESPECIALLY WITH ALL THE DAMAGE COMING IN SOUTH OF THE CAPITAL REGION AT THIS TIME. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... IN THE WAKE OF THE STORM...THERE MAY BE SOME LINGERING LAKE EFFECT SNOW SHOWERS INTO THE FAR WESTERN PARTS OF THE FORECAST AREA. OTHERWISE...HIGH PRESSURE WILL BEGIN TO NOSE INTO REGION FROM THE SOUTHWEST FOR THE SECOND HALF OF THE NIGHT...WHICH WILL HELP LOWER THE INVERSION HEIGHT AND SQUELCH ANY REMAINING LAKE EFFECT. THE HIGH PRESSURE AREA WILL BE OVER THE REGION ON SATURDAY...AND JUST EAST OF THE REGION BY SUNDAY. THIS WILL PROVIDE FOR A DRY WEEKEND WITH MAINLY CLEAR TO PARTLY CLOUDY SKIES FOR MOST OF THE REGION...BUT WEAK WARM FRONTAL OVERUNNING COULD PRODUCE MOSTLY CLOUDY CONDITIONS OVER THE NORTHWEST HALF OF THE FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING. TEMPERATURES WILL BE VERY COLD ON SATURDAY...IN THE MID TEENS TO MID 20S...BUT WILL WARM UP TO HIGHS IN THE 30S ON SUNDAY. VERY COLD TEMPS FRIDAY NIGHT AND SATURDAY NIGHT WITH LOW TEMPS RANGING FROM THE SINGLE NUMBERS BELOW ZERO TO THE MID TEENS. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... IN THE WAKE OF THE STORM...THERE MAY BE SOME LINGERING LAKE EFFECT SNOW SHOWERS INTO THE FAR WESTERN PARTS OF THE FORECAST AREA. OTHERWISE...HIGH PRESSURE WILL BEGIN TO NOSE INTO REGION FROM THE SOUTHWEST FOR THE SECOND HALF OF THE NIGHT...WHICH WILL HELP LOWER THE INVERSION HEIGHT AND SQUELCH ANY REMAINING LAKE EFFECT. THE HIGH PRESSURE AREA WILL BE OVER THE REGION ON SATURDAY...AND JUST EAST OF THE REGION BY SUNDAY. THIS WILL PROVIDE FOR A DRY WEEKEND WITH MAINLY CLEAR TO PARTLY CLOUDY SKIES FOR MOST OF THE REGION...BUT WEAK WARM FRONTAL OVERRUNNING COULD PRODUCE MOSTLY CLOUDY CONDITIONS OVER THE NORTHWEST HALF OF THE FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING. TEMPERATURES WILL BE VERY COLD ON SATURDAY...IN THE MID TEENS TO MID 20S...BUT WILL WARM UP TO HIGHS IN THE 30S ON SUNDAY. VERY COLD TEMPS FRIDAY NIGHT AND SATURDAY NIGHT WITH LOW TEMPS RANGING FROM THE SINGLE NUMBERS BELOW ZERO TO THE MID TEENS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL DOMINATE OUR WEATHER FOR SUNDAY...WITH PARTLY CLOUDY SKIES AND AFTERNOON TEMPERATURES CLOSE TO SEASONAL NORMAL. THE HIGH SLIDES EAST OFF THE COAST SUNDAY NIGHT AS THE NEXT SURFACE LOW BRINGS THE LOW LEVEL WINDS BACK TO A SOUTHWESTERLY DIRECTION...BRINGING IN WARMTH AND MOISTURE FROM THE GULF. THE SURFACE LOW MOVES NORTH INTO CANADA MONDAY...WITH OVERRUNNING PRECIP SPREADING INTO THE REGION WHICH IS LIKELY TO CHANGE FROM SNOW TO FREEZING RAIN AND SLEET AND LATER TO RAIN AS SURFACE TEMPERATURES CLIMB ABOVE FREEZING. A COLD FRONT WILL PASS THROUGH THE REGION LATE MONDAY NIGHT WHICH WILL TURN ANY LIQUID OR FREEZING PRECIPITATION BACK TO SNOW TOWARD DAYBREAK...BUT AS TEMPERATURES WARM FROM DOWNSLOPING AND SUBSIDENCE THE PRECIPITATION WILL CHANGE TO RAIN ACROSS MOST OF THE REGION FROM THE MOHAWK VALLEY SOUTH DURING THE DAY ON TUESDAY. ANOTHER WEAK LOW WILL MOVE ALONG THE AIR MASS BOUNDARY WEDNESDAY AND KEEP THE WEATHER OVER THE REGION UNSETTLED. WITH THE REGION IN THE COLD AIR MASS THE P-TYPE WILL MOST LIKELY BE SNOW EXCEPT FOR A SMALL AREA OF MIX IN THE MID HUDSON REGION OF NY AND SOUTHERN LITCHFIELD COUNTY CT. HIGH PRESSURE THEN WEDGES ITS WAY INTO THE REGION FROM THE WEST ON THURSDAY TO GIVE US A BRIEF BREAK IN THE ACTION...WITH MIDDAY TEMPERATURES FROM THE MID 20S TO THE MID 30S...JUST SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... IFR/LIFR WILL PERSIST THE REMAINDER OF THE OVERNIGHT PERIOD. A VARIETY OF PRECIP TYPES WITH MAINLY SLEET/FREEZING RAIN EXPECTED OVERNIGHT WITH THE TREMENDOUS WARM AIR ALOFT AND SURFACE TEMPERATURES AT OR JUST BELOW THE FREEZING MARK. MID LEVEL DRY SLOT APPROACHES AROUND 10-12Z FRIDAY WHICH WILL CUT OFF ICE NUCLEI AND RESULT PERIODS OF DRIZZLE/FREEZING DRIZZLE BUT STILL IFR BUT IMPROVING TO MVFR LATER IN THE MORNING. DEFORMATION /WRAP AROUND/ ZONE APPROACHES TOWARD 15Z WITH A PERIOD OF SNOW AND/OR SLEET FOR MOST AREAS /WOULD NEED TO WATCH FOR LOCAL EFFECT FROM GFL-ALB FOR BRIEF IFR CONDITIONS/...UNTIL THIS AFTERNOON WHEN DRIER AIR CONTINUES TO FILTER IN THE WAKE OF THIS STORM WITH VFR CONDITIONS RETURNING. OUTLOOK... FRI NT-MON AM...VFR. NO SIG WX. MON PM-TUE...MVFR...POSS IFR. CIG/VIS. CHC SHRAS. && .HYDROLOGY... A FLOOD WATCH REMAINS IN EFFECT FOR THE SOUTHEASTERN CATSKILLS... THE MID HUDSON AND TACONIC REGIONS OF NEW YORK...BERKSHIRE COUNTY IN MASSACHUSETTS AND LITCHFIELD COUNTY CONNECTICUT. THE TOPIC OF MOST CONCERN IS THE HOUSATONIC RIVER. RAIN AND MELTING SNOW OVER THE REGION TUESDAY NIGHT AND EARLY WEDNESDAY BROUGHT THE HOUSATONIC RIVER UP ONE TO TWO FEET IN WESTERN MASSACHUSETTS AND CONNECTICUT. TWO TO THREE INCHES OF ADDITIONAL PRECIPITATION ARE FORECAST ACROSS THE HOUSATONIC VALLEY...WITH MOST FALLING BETWEEN 7 PM THURSDAY AND 7 AM FRIDAY. ALTHOUGH TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH AT THE GROUND FOR FREEZING RAIN...FORECAST PRECIPITATION RATES OF ONE QUARTER TO ONE THIRD OF AN INCH PER HOUR WOULD BE HIGH ENOUGH SO THAT MUCH OF THE RAIN WILL RUN OFF THE GROUND INTO STREAMS AND RIVERS BEFORE FREEZING. RIVER MODELS INDICATE THAT RIVERS IN THE WATCH AREA COULD REACH MINOR FLOOD LEVELS. IN ADDITION...URBAN AND POOR DRAINAGE FLOODING IS ALSO POSSIBLE. LAST WINTER WE HAD A COUPLE OF EVENTS WHERE FREEZING RAIN OCCURRED WITH HIGH RAINFALL RATES AND FLOODING WAS ALSO REPORTED IN THE SAME AREA. WITH TEMPERATURES EXPECTED TO CLIMB A BIT ABOVE FREEZING FOR SOUTHERN LITCHFIELD...FLOOD CONCERNS HERE ARE MORE LI A FLOOD WARNING ISSUED WEDNESDAY FOR THE BATTENKILL IN SOUTHERN VERMONT WAS CANCELED THIS MORNING AS THE RIVER DROPPED BELOW ITS 6 FOOT FLOOD STAGE OVERNIGHT. IT WILL RECEDE A FEW INCHES MORE TODAY...AND CONTINUE TO RECEDE FRIDAY AS TEMPERATURES ACROSS SOUTHERN VERMONT WILL REMAIN BELOW FREEZING. RIVER ICE/ICE JAMS WILL NOT BE A CONCERN. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH FRIDAY EVENING FOR CTZ001-013. ICE STORM WARNING UNTIL 1 PM EST FRIDAY FOR CTZ001. WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR CTZ013. NY...FLOOD WATCH THROUGH FRIDAY EVENING FOR NYZ058>061-063>066. ICE STORM WARNING UNTIL 1 PM EST FRIDAY FOR NYZ058>061-063>066. WINTER STORM WARNING UNTIL 1 PM EST FRIDAY FOR NYZ032-033- 038>043-047>054-082>084. MA...FLOOD WATCH THROUGH FRIDAY EVENING FOR MAZ001-025. ICE STORM WARNING UNTIL 1 PM EST FRIDAY FOR MAZ001-025. VT...WINTER STORM WARNING UNTIL 1 PM EST FRIDAY FOR VTZ013>015. && $$ SYNOPSIS...WASULA NEAR TERM...WASULA SHORT TERM...MAGLARAS LONG TERM...RCK AVIATION...BGM HYDROLOGY...RCK WWW.WEATHER.GOV/ALBANY ct 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 DES MOINES IA 1149 AM CST FRI DEC 12 2008 .UPDATED 12/18Z AVIATION DISCUSSION... .SHORT TERM...TODAY BIGGEST CONCERN TODAY WILL BE TEMPS. 08Z SFC ANLYS PLACES HIGH OVER SWRN MN WITH CDFNT PUSHING THROUGH WI INTO NRN IA...BECOMING A WRMFNT THROUGH THE ERN DAKOTAS. SFC RIDGE THROUGH HIGH CENTER...FROM KS INTO MN...WILL KEEP WINDS LIGHT AND MIXING DOWN WITH OCCASIONAL STRATUS SO EXPECT LITTLE REBOUND THROUGH AT LEAST MIDDAY. HOWEVER HIGH DOES RETREAT WITH INCREASING SWLY WNDS BY AFTERNOON. GFS RAW TEMPS MOST BULLISH ON WARM UP...WITH NAM/SREF NUMBERS COOLER. CONSIDERING THE MAGNITUDE OF THE COLD AIR IS NOT BEING HANDLED BY THE MODELS WELL...HAVE TOWARD OR BELOW EVEN THE COOLEST NAM MOS. STRATUS MAY BE IN AND OUT TODAY...WITH NAM/GFS/RUC DENDRITIC RH ALL SUGGESTING SOME FLURRIES ARE POSSIBLE WITH PATCH OF LOW CLOUDS EXITING SIOUXLAND REGION. .LONG TERM...TONIGHT THROUGH THURSDAY HIGH BUILDS EAST TONIGHT WITH WARM AIR ADVECTION ALREADY ADVANCING ACROSS THE REGION TONIGHT. MODELS CONTINUE TO ADVERTISE POSSIBLE STRATUS...FOG AND POSSIBLE DRIZZLE ALREADY BY SATURDAY AFTERNOON OVER NORTHERN IOWA. FOR THE MOMENT...NOT MUCH SNOW SOUTHWEST OF THE AREA THOUGH ANY RETURN OF MOISTURE OVER THE SNOW COVER REMAINING ACROSS SOUTHERN AND CENTRAL IOWA IS LIKELY TO PRODUCE SOME FOG AND OR STRATUS BY SATURDAY...POSSIBLY LINGERING ACROSS THE AREA INTO SUNDAY. BEST AREAS CONTINUE TO APPEAR TO BE THE NORTH AND EAST. SOUNDINGS ALSO SUGGEST SOME DRIZZLE AND LOWER VSBYS WILL CONTINUE INTO SATURDAY NIGHT AHEAD OF THE STRONGER WAVE CROSSING THE STATE. TEMPS SOMEWHAT OF A CHALLENGE THE NEXT FEW DAYS WITH WARM AIR ARRIVING TONIGHT. SHOULD NOT SEE MUCH OF A DROP IN OVERNIGHT LOWS FRI NIGHT WITH DECENT WARM UP ON SATURDAY. GUIDANCE SEEMS A BIT HIGH ...ESPECIALLY MAV AND HAVE RAISED HIGHS A FEW DEGREES SOUTH AND CENTRAL WHILE LEAVING THE NORTH IN LINE WITH PREVIOUS PACKAGE. THE WARMEST AIR SHOULD CROSS THE REGION SATURDAY NIGHT...KEEPING MINS WELL ABOVE NORMAL. AHEAD OF THE STRONG ARCTIC FRONT ON SUNDAY...SOME LIGHT RAIN SHOULD DEVELOP IN THE WARM SECTOR AND SOME SNOW SHOWERS BEHIND THE BOUNDARY FOR SUNDAY AFTERNOON. RATHER COLD AIR POISED TO DROP SOUTH SUNDAY NIGHT AND MONDAY THOUGH MODELS HAVE BACKED OFF ON VALUES OF -20C AT H850 WITH THE COLDER AIR LAGGING OVER THE DAKOTAS AND MN. WINDS WILL BE QUITE BRISK SUNDAY NIGHT WITH GUSTS TO 30 TO 35 MPH AND GRADUALLY DIMINISHING MONDAY AS THE HIGH BUILDS ACROSS THE REGION. BOTH THE EURO/GFS IN GENERAL AGREEMENT FOR MONDAY NIGHT AND TUESDAY WITH HIGH SLIDING EAST AND ZONE OF WARM AIR ADVECTION SETTING UP ACROSS A BAROCLINIC ZONE JUST TO THE SOUTH OF THE STATE. THIS WILL SET THE STAGE FOR ANOTHER ROUND OF PRECIP...IN THE FORM OF LIGHT SNOW. HAVE ADDED CHANCE POPS ACROSS THE SOUTH AND SLIGHTS NORTH FOR NOW...FROM PREVIOUS PACKAGE WHICH WAS DRY. IN THE OUT PERIODS EURO HAS BACKED OFF ON PRECIP ON WED NIGHT WHILE GFS STILL SHOWS A WEAK SIGNATURE. TEMPS THROUGH THE PERIOD WILL CONTINUE TO BE COLD WITH MONDAY AND TUES NIGHT IN THE SINGLE DIGITS ABOVE AND BELOW ZERO OVER AT LEAST THE NORTH HALF...AND LOWER TEENS SOUTH. ANOTHER WAVE IS EXPECTED BY THE END OF THE WEEK. GFS CONTINUES FASTER AT THIS TIME WITH THE ARRIVAL OF THE PRECIP BY THURSDAY WHILE THE EURO IS ABOUT 12 HOURS SLOWER. PREFER THE SLOWER SOLN AT THIS TIME. && .AVIATION...12/12Z STRATUS SHIELD CURRENTLY BISECTS THE FORECAST AREA FROM NW TO SE AND WILL CONTINUE TO PUSH EAST OUT OF THE AREA DURING THE AFTERNOON HOURS. SOUTHERLY FLOW WILL INCREASE TONIGHT AND TRANSPORT LOW LEVEL MOISTURE INTO THE NORTH. EXPECT MVFR CIGS SPREADING FROM NW TO SE ACROSS IOWA SATURDAY MORNING WITH SOME LIGHT BR ALSO POSSIBLE. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BSS AVIATION...KINNEY LONG TERM...REV ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 614 AM CST FRI DEC 12 2008 .SHORT TERM...TODAY BIGGEST CONCERN TODAY WILL BE TEMPS. 08Z SFC ANLYS PLACES HIGH OVER SWRN MN WITH CDFNT PUSHING THROUGH WI INTO NRN IA...BECOMING A WRMFNT THROUGH THE ERN DAKOTAS. SFC RIDGE THROUGH HIGH CENTER...FROM KS INTO MN...WILL KEEP WINDS LIGHT AND MIXING DOWN WITH OCCASIONAL STRATUS SO EXPECT LITTLE REBOUND THROUGH AT LEAST MIDDAY. HOWEVER HIGH DOES RETREAT WITH INCREASING SWLY WNDS BY AFTERNOON. GFS RAW TEMPS MOST BULLISH ON WARM UP...WITH NAM/SREF NUMBERS COOLER. CONSIDERING THE MAGNITUDE OF THE COLD AIR IS NOT BEING HANDLED BY THE MODELS WELL...HAVE TOWARD OR BELOW EVEN THE COOLEST NAM MOS. STRATUS MAY BE IN AND OUT TODAY...WITH NAM/GFS/RUC DENDRITIC RH ALL SUGGESTING SOME FLURRIES ARE POSSIBLE WITH PATCH OF LOW CLOUDS EXITING SIOUXLAND REGION. .LONG TERM...TONIGHT THROUGH THURSDAY HIGH BUILDS EAST TONIGHT WITH WARM AIR ADVECTION ALREADY ADVANCING ACROSS THE REGION TONIGHT. MODELS CONTINUE TO ADVERTISE POSSIBLE STRATUS...FOG AND POSSIBLE DRIZZLE ALREADY BY SATURDAY AFTERNOON OVER NORTHERN IOWA. FOR THE MOMENT...NOT MUCH SNOW SOUTHWEST OF THE AREA THOUGH ANY RETURN OF MOISTURE OVER THE SNOW COVER REMAINING ACROSS SOUTHERN AND CENTRAL IOWA IS LIKELY TO PRODUCE SOME FOG AND OR STRATUS BY SATURDAY...POSSIBLY LINGERING ACROSS THE AREA INTO SUNDAY. BEST AREAS CONTINUE TO APPEAR TO BE THE NORTH AND EAST. SOUNDINGS ALSO SUGGEST SOME DRIZZLE AND LOWER VSBYS WILL CONTINUE INTO SATURDAY NIGHT AHEAD OF THE STRONGER WAVE CROSSING THE STATE. TEMPS SOMEWHAT OF A CHALLENGE THE NEXT FEW DAYS WITH WARM AIR ARRIVING TONIGHT. SHOULD NOT SEE MUCH OF A DROP IN OVERNIGHT LOWS FRI NIGHT WITH DECENT WARM UP ON SATURDAY. GUIDANCE SEEMS A BIT HIGH ...ESPECIALLY MAV AND HAVE RAISED HIGHS A FEW DEGREES SOUTH AND CENTRAL WHILE LEAVING THE NORTH IN LINE WITH PREVIOUS PACKAGE. THE WARMEST AIR SHOULD CROSS THE REGION SATURDAY NIGHT...KEEPING MINS WELL ABOVE NORMAL. AHEAD OF THE STRONG ARCTIC FRONT ON SUNDAY...SOME LIGHT RAIN SHOULD DEVELOP IN THE WARM SECTOR AND SOME SNOW SHOWERS BEHIND THE BOUNDARY FOR SUNDAY AFTERNOON. RATHER COLD AIR POISED TO DROP SOUTH SUNDAY NIGHT AND MONDAY THOUGH MODELS HAVE BACKED OFF ON VALUES OF -20C AT H850 WITH THE COLDER AIR LAGGING OVER THE DAKOTAS AND MN. WINDS WILL BE QUITE BRISK SUNDAY NIGHT WITH GUSTS TO 30 TO 35 MPH AND GRADUALLY DIMINISHING MONDAY AS THE HIGH BUILDS ACROSS THE REGION. BOTH THE EURO/GFS IN GENERAL AGREEMENT FOR MONDAY NIGHT AND TUESDAY WITH HIGH SLIDING EAST AND ZONE OF WARM AIR ADVECTION SETTING UP ACROSS A BAROCLINIC ZONE JUST TO THE SOUTH OF THE STATE. THIS WILL SET THE STAGE FOR ANOTHER ROUND OF PRECIP...IN THE FORM OF LIGHT SNOW. HAVE ADDED CHANCE POPS ACROSS THE SOUTH AND SLIGHTS NORTH FOR NOW...FROM PREVIOUS PACKAGE WHICH WAS DRY. IN THE OUT PERIODS EURO HAS BACKED OFF ON PRECIP ON WED NIGHT WHILE GFS STILL SHOWS A WEAK SIGNATURE. TEMPS THROUGH THE PERIOD WILL CONTINUE TO BE COLD WITH MONDAY AND TUES NIGHT IN THE SINGLE DIGITS ABOVE AND BELOW ZERO OVER AT LEAST THE NORTH HALF...AND LOWER TEENS SOUTH. ANOTHER WAVE IS EXPECTED BY THE END OF THE WEEK. GFS CONTINUES FASTER AT THIS TIME WITH THE ARRIVAL OF THE PRECIP BY THURSDAY WHILE THE EURO IS ABOUT 12 HOURS SLOWER. PREFER THE SLOWER SOLN AT THIS TIME. && .AVIATION...12/12Z PRIMARY CONCERN THROUGH PERIOD WILL BE CLOUD TRENDS. PATCHY MVFR STRATUS WILL AFFECT ALL SITES THIS MORNING. PREVIOUS POTENTIAL FOR IFR CIGS HAS DIMINISHED. ADDITIONAL MVFR CIGS MAY DEVELOP THIS AFTERNOON OR TONIGHT AT ALL SITES...BUT POTENTIAL NOT GREAT ENOUGH TO MENTION AT THE MOMENT. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/AVIATION...BSS LONG TERM...REV ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1239 AM CST FRI DEC 12 2008 .SHORT TERM...TONIGHT A BAND OF PRECIP IS HEADING QUICKLY SOUTH OUT OF IOWA THIS AFTERNOON AFTER DEPOSITING A LIGHT DUSTING AT A FEW LOCATIONS. MORE LIGHT SNOW IS UPSTREAM OVER PORTIONS OF THE DAKOTAS AND MINNESOTA...AND WILL IMPACT THE FORECAST AREA TONIGHT. OF THE SHORT RANGE DETERMINISTIC MODELS AND THE SREF...THE GFS AND RUC HAVE THE BEST HANDLE ON THE CURRENT SNOW IN THE DAKOTAS. THE RUC ALSO MODELED THE MORNING WEATHER WELL. ADDITIONAL SHORT WAVE ENERGY DROPPING SOUTHEAST ALONG A WEAK SURFACE TROUGH WILL SUPPORT ADDITIONAL LIGHT SNOW SHOWERS TONIGHT. MODEST FORCING AND MOISTURE WILL LIMIT ANY ACCUMULATION TO A HALF INCH OR LESS. A STRATUS DECK SHOULD KEEP OVERNIGHT TEMPS FROM COMPLETELY BOTTOMING OUT...BUT STILL STAYED BELOW THE COOLEST FWC/NGM MOS GIVEN THE STRONG CAA AND LINGERING SNOW PACK. .LONG TERM...FRIDAY THRU THURSDAY WL SEE TRANSITION FROM PREDOMINANT NORTHWEST FLOW TO SOUTHWEST FLOW DURING THIS PERIOD. SOME LINGERING SNOW FLURRIES MAY REMAIN ON FRIDAY MORNING ACRS THE NORTHWEST...HOWEVER WL BEGIN TO SEE WAA INCREASE THROUGH THE DAY AS SFC RIDGING SLIDES TO THE EAST. HAVE STAYED AT OR ABOVE GUIDANCE IN THE SOUTH AND WEST WHERE CONDITIONS WL BE GOOD FAR WARMING...LITTLE SNOW COVER AND DECENT SOUTH TO SOUTHWEST SFC WINDS. FARTHER NORTH...SNOW COVER AND MORE CLOUDINESS WL PUT SOME LIMIT ON THE AMOUNT OF WARMING. THE WARMING WL CONTINUE INTO FRIDAY NIGHT AND SATURDAY AS HEIGHTS INCREASE IN RESPONSE TO DEEPENING WESTERN TROF. WL BEGIN TO SEE HIGHER DEWPOINTS IMPINGE UPON THE STATE ON SATURDAY AND ANTICIPATE THE DEVELOPMENT OF STRATUS AS THE WARMER AND RELATIVELY MORE MOIST AIR TRAVERSES THE COOLER GROUND. NAM AND GFS PRODUCE SOME LIGHT PCPN FROM A FAIR AMOUNT OF ISENTROPIC LIFT AND HAVE INCLUDED SOME LOW POPS AS WELL. SOUNDINGS ARE QUITE SATURATED IN THE LOWER LEVELS BY LATE SATURDAY AND THIS CONTINUES INTO EARLY SUNDAY. ANTICIPATE LOW CLOUDS AND DRIZZLE/LGT RAIN INTO SATURDAY NIGHT AS WARM SECTOR REMAINS OVER THE STATE. WITH MORE MOISTURE PULLING INTO IA OVER THE SNOW COVER IN THE NORTH...WOULDN/T BE SURPRISED TO HAVE ADVECTION FOG DEVELOP IN THOSE LOCATIONS. TEMPS WL HOLD STEADY ON SATURDAY NIGHT AS WARM SOUTHERLY FLOW PERSIST ALL NIGHT. SFC LOW TRANSITS WESTERN IA ON SUNDAY MORNING WITH COLD FRONT QUICKLY PUSHING THROUGH THE STATE BY AFTERNOON. ANTICIPATE EARLY HIGHS IN THE WEST WITH TEMPERATURES CRASHING FROM WEST TO EAST DURING THE AFTERNOON BEHIND THE FRONT. WL LIKELY SEE SOME SHOWERS DEVELOP EAST OF I35 BY LATE MORNING/EARLY AFTERNOON AHEAD OF THE BOUNDARY BUT MOST SIGNIFICANT PCPN WL BE TO THE EAST AS THE MOISTURE AXIS SHIFTS INTO IL/WI BY SUNDAY EVENING. PCPN WL REMAIN IN THE FAR SOUTHEAST DURING THE NIGHT AND MAY SEE SOME FREEZING RAIN AS THE SHALLOW COLD AIR UNDERCUTS THE STRONG SOUTHERLY AND MOIST FLOW. HOWEVER...ONLY ANTICIPATE A BRIEF PERIOD OF THIS BEFORE SOUNDING CRASH BELOW FREEZING WITH ALL SNOW BEFORE ENDING IN MOST LOCATIONS BY EARLY MONDAY MORNING. ARCTIC AIR THEN SETTLES INTO THE STATE WITH TEMPERATURES A GOOD 20 TO 30 DEGREES COOLER THAN SUNDAY. CONFIDENCE IN THE FORECAST BEYOND MONDAY IS RATHER LOW AS SOUTHWEST FLOW PERSISTS. NEW 12Z RUNS OF THE GFS AND ECMWF WOULD INDICATE ANOTHER SYSTEM BRINGING SNOW TO THE STATE BY TUESDAY WITH SOME BREAK ON WEDNESDAY INTO EARLY THURSDAY PRIOR TO ANOTHER SYSTEM LATE IN THE WORK WEEK. THE GRIDS DONT NECESSARILY REFLECT THIS NEWER DATA AS EXTENDED GRIDS HAD ALREADY BEEN COMPLETED. SOME MODIFICATION TO THESE LATER PERIODS WL BE LIKELY AS TIMING BECOME BETTER DEFINED. TEMPS AT OR BELOW NORMAL APPEAR TO REMAIN FOR MUCH OF THE EXTENDED AS WELL. && .AVIATION...12/06Z PRIMARY CONCERN THROUGH PERIOD WILL BE CLOUD TRENDS. PERIODS OF MVFR STRATUS WILL AFFECT ALL SITES EXCEPT MCW EARLY THIS MORNING. THERE IS ALSO SOME POTENTIAL FOR IFR CIGS AT FOD WITH SUB 1000FT CIGS OVER SERN MN MOVE SW BUT CHANCES NOT GREAT ENOUGH TO MENTION AT THE MOMENT. ADDITIONAL MVFR CIGS MAY DEVELOP THIS AFTERNOON AT ALL SITES...BUT ONLY MENTIONED AT MCW/ALO WHERE CHANCES APPEAR BETTER FOR NOW. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...KINNEY/DONAVON LONG TERM...COGIL AVIATION...SMALL ia 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 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 TWIN CITIES/CHANHASSEN MN 814 AM CST FRI DEC 12 2008 .UPDATE...TO AVIATION FORECAST DISCUSSION BELOW && .PREV DISCUSSION.../341 AM CST FRI DEC 12 2008/ ..A HIGH IMPACT STORM SYSTEM WILL LIKELY AFFECT THE REGION THIS WEEKEND... BUSY FORECAST PERIOD AHEAD WITH WARM ADVECTION AND LOW SNOW CHANCES COMING UP TODAY WITH A SIGNIFICANT WINTER STORM IN THE WORKS FOR THE REGION BEGINNING SATURDAY AND WINDING DOWN MONDAY. THE FORECAST AREA IS EXPECTED TO AVOID THE MOST SIGNIFICANT PRECIPITATION AMOUNT WISE WITH THAT REMAINING ACROSS NORTHERN MINNESOTA...WISCONSIN AND INTO THE U.P. OF MICHIGAN. HOWEVER...A MIX OF PRECIPITATION WILL ARRIVE AHEAD OF THE LOW LATER SATURDAY AND TURN TO SNOW BY LATE SUNDAY AS A BLAST OF ARCTIC AIR ARRIVES WITH 25 TO 35+ MPH NORTHWESTERLY WINDS POSSIBLE ACROSS WESTERN AREAS. WEST CENT MN AND NORTHERN PORTIONS OF CENTRAL MN WILL SEE THE MOST SNOW ACCUMULATION IN THE CWA /WITH MUCH MORE SNOW TO THE NORTH OF THE CWA/ BY MONDAY MORNING. SOME OF THE COLDEST TEMPERATURES OF THE SEASON THUS FAR WILL BE FOUND INTO TUESDAY. MORE DETAILS FOLLOW BELOW. EARLY MORNING WATER VAPOR IMAGERY SHOWS VERY AMPLIFIED PATTERN OVER EASTERN NORTH AMERICA WHERE LONGWAVE TROUGH REMAINS IN PLACE IN TWO STREAMS. THE NORTHERN STREAM STEMS FROM A MULTI-SPOKED UPPER LOW OVER HUDSON BAY AND IS PROVIDING CONTINUED NORTHWEST FLOW OVERHEAD OF THE LOCAL AREA. THE SOUTHERN STREAM WHICH EXTENDS FROM THE OHIO RIVER VALLEY SOUTHWARD HAS A WELL ORGANIZED CLOSED LOW WORKING NORTHEASTWARD OVER THE APPALACHIANS WITH A DEEP COASTAL LOW DEVELOPING IN ASSOCIATION WITH IT. LOOKING IN A BIT MORE DETAIL...A SERIES OF WEAK SHORTWAVES APPEAR IN THE LOCAL AREA WITH ONE SUCH WAVE EXITING TO THE SOUTH OF THE FORECAST AREA THIS MORNING AND ANOTHER MORE SHEARED WAVE DROPPING SOUTHEAST ACROSS ALBERTA TOWARDS THE INTERNATIONAL BORDER. THE WESTERN U.S. IS SEEING A TROUGH DROP SOUTHWARD ALONG THE CALIFORNIA COAST BUT THE TROUGH THAT IS OF GREATER INTEREST IS JUST OFF THE CENTRAL BRITISH COLUMBIA COAST. THIS TROUGH WILL PLAY A KEY ROLE IN DEVELOPING THE UPCOMING WINTER STORM. TODAY...HIGH PRESSURE WILL DRIFT TO THE EAST TODAY ALLOWING WINDS TO SHIFT TO THE SOUTH. CLIPPER TO THE NORTHWEST OF THE AREA WILL DROP SOUTHEASTWARD HELPING TO TIGHTEN THE PRESSURE GRADIENT AS WELL AS ESTABLISH WARM ADVECTION OVER THE AREA. SHOULD SEE A NICE RECOVERY OF TEMPS FROM THEIR CURRENT SUB-ZERO VALUES INTO THE UPPER 20S IN THE WEST AND MID/UPPER TEENS EAST. THERE WILL BE A SLIGHT CHANCE FOR SNOW SHOWERS ACROSS THE NORTH THIRD OR SO OF THE AREA LATER THIS AFTERNOON AS THE UPPER WAVE PASSES AND BEST MID LEVEL TEMPERATURE GRADIENT LINES UP WITH SUFFICIENTLY DEEP MOISTURE. SOUTH WINDS WILL KEEP TEMPERATURES FROM FALLING MUCH IF AT ALL TONIGHT...WITH A RISE EVEN POSSIBLE TOWARDS DAYBREAK SATURDAY. LIGHT SNOW CHANCES WILL LINGER IN THE NORTHEAST CWA. SATURDAY-MONDAY...MODELS ARE STILL IN PRETTY GOOD AGREEMENT WITH REGARD TO THE BRITISH COLUMBIA LOW REACHING THE PAC NORTHWEST LATER TONIGHT. ITS ASSOCIATED SFC LOW COMES ASHORE OVER WASHINGTON STATE THIS AFTERNOON AS THE SFC LOW ASSOCIATED WITH A WEAK CLIPPER PREVIOUSLY MENTIONED TO BE DROPPING ACROSS ALBERTA THIS MORNING REACHES THE U.S./CANADIAN BORDER. THE SFC PATTERN BECOMES RATHER COMPLEX ALONG THE INTERNATIONAL BORDER BETWEEN THESE TWO SYSTEMS AS LOW-MID LEVEL BAROCLINIC ZONE TIGHTENS AS SOUTHWESTERLY FLOW AHEAD OF THE WEST COAST UPPER TROUGH SENDS WARM AIR NORTH AND THE CLIPPER SENDS COLD AIR SOUTH WITH 80-90KT UPPER JET DEVELOPING ABOVE. THE ADVANCING TROUGH AND ASSOCIATED HEIGHT FALLS SPAWN STRONG SFC CYCLOGENESIS OVER MONTANA AND WYOMING TONIGHT WITH DEVELOPING WARM FRONTAL BOUNDARY/INVERTED TROUGH SETTING UP FROM SOUTHWEST TO NORTHEAST FROM WESTERN SODAK INTO NORTHWESTERN MN SATURDAY AFTERNOON AS THE SFC LOW SETTLES INTO NE COLORADO. THE PRESSURE GRADIENT ACROSS THE CENTRAL U.S. TIGHTENS PROVIDING STRONG SOUTHERLY WINDS INTO THE LOCAL AREA. LOW/MID LEVEL WARM ADVECTION WILL BE STRONGEST OVER NORTHERN AND EASTERN PORTIONS OF THE CWA THIS EVENING WITH H85 TEMPS HOVERING AROUND 0C DURING THE DAY SATURDAY. MID LEVEL DRY AIR IS ABUNDANT THOUGH WEAK ASCENT REMAINS SO PRECIPITATION CHANCES SATURDAY DON/T LOOK ALL THAT HIGH UNTIL AFTERNOON WHEN A MID LEVEL TROUGH SPEEDS NORTHEASTWARD BRINGING ENHANCED WARM ADVECTION AND SLIGHTLY DEEPER MOISTURE. THE STRONGER PORTION OF THE WAVE WILL BE ACROSS IOWA AND INTO CENTRAL WISCONSIN. BETTER FORCING WILL WORK IN SATURDAY EVENING/NIGHT ACROSS WESTERN AND NORTHERN PARTS OF THE AREA. PRECIP TYPE WILL BE THE MAIN CHALLENGE ALONG WITH SFC TEMPS. NAM AND GFS FORECAST SOUNDINGS ARE DIFFERENT IN THE DETAILS...AND IT IS STILL A BIT FAR OUT TO COUNT ON SPECIFICS FROM THEM BUT THEY SHOULD PROVIDE A GENERAL IDEA OF HOW P-TYPE WILL PAN OUT. TOP DOWN ANALYSIS INDICATES THAT SNOW AND SLEET WOULD BE THE DOMINANT P-TYPES ACROSS THE NORTH SATURDAY AFTERNOON AND EARLY EVENING WITH SOUNDINGS ONLY WARM ENOUGH TO SUPPORT PARTIAL MELTING. SFC TEMPS SHOULD HOVER AROUND FREEZING DURING THE AFTERNOON BUT SOUNDINGS SHOW AIR COLD ENOUGH ABOVE THE SFC TO ALLOW RE-FREEZING. PROFILES WARM SATURDAY NIGHT AS PRECIP CHANCES EXPAND WITH RAIN BECOMING MORE LIKELY TO MIX IN ACROSS EAST CENTRAL MN AND WEST CENT WI. FZRA WILL BECOME A CONCERN ACROSS NORTHERN PORTIONS OF EAST CENT MN TOWARDS LATE EVENING/EARLY OVERNIGHT WITH SFC TEMPS CONTINUING TO HOVER AROUND FREEZING. SFC TEMPS MAY EVEN RISE OVERNIGHT. SOUNDINGS IN THESE AREAS LOOK MORE CONDUCIVE FOR RAIN OR SNOW. ACROSS SOUTHERN AND EASTERN PORTIONS OF THE CWA WESTERN AREAS WILL SEE COLD AIR DROP BY DAYBREAK SUNDAY ALLOWING A QUICK TRANSITION TO ALL SNOW. THE SFC LOW WILL MOVE INTO SOUTHERN MINNESOTA SUNDAY MORNING WITH THE INVERTED TROUGH POSITIONED OVER EASTERN MINNESOTA AND SHIFTING EAST AS THE LOW MOVES NORTHEAST. COLD AIR WILL RAPIDLY MOVE IN FROM THE NORTH AND WEST CHANGING PRECIP OVER TO ALL SNOW FROM WEST TO EAST THROUGH THE DAY. VERY WARM AIR RIDES UP AHEAD OF THE LOW INTO FAR EAST CENT MN AND WEST CENT WI SO A PERIOD OF STRAIGHT RAIN IS POSSIBLE THERE. MODELS STILL SHOW DEEP LAYER MOISTURE DECREASING ACROSS THE EAST HALF OF THE AREA WHICH SEEMS REASONABLE. THIS WILL LIMIT PRECIP AMOUNTS IN THE WARM AIR AND TO AN EXTENT ACROSS THE WESTERN CWA IN THE COLD AIR VS. AREAS TO THE NORTH. HANDLING OF THE UPPER TROUGH VARIES BY MODEL WITH THE POSITION OF THE SFC LOW NOW VARYING BY SUNDAY EVENING. ALL OF THIS CREATES COMPLICATIONS WITH POSITION OF ANY DRY SLOT AND LOCATION OF BETTER BANDING OF SNOW. STILL EXPECT THAT PRIMARY BANDING WILL BE TO THE NORTH OF THE AREA BUT HAVE CONCERNS ABOUT HEAVY SNOW POTENTIAL ACROSS NORTHWEST PORTIONS OF THE CWA FROM CANBY TOWARDS ST. CLOUD. WINDS WILL INCREASE MARKEDLY FROM THE NORTHWEST AS THE LOW LIFTS NORTHEAST. 25 TO 35 MPH WINDS ARE LIKELY WITH GUSTS OVER 35 MPH EXPECTED. THE STRONGEST WINDS WILL BE ACROSS WEST CENTRAL MINNESOTA. WATCH REASONING...DECIDED TO ISSUE A BLIZZARD WATCH FOR THE WESTERN TIER OF COUNTIES OR FROM STEVENS TO YELLOW MEDICINE FROM 12Z SUNDAY TO 12Z MONDAY. MAIN CONCERN HERE IS THE WIND. SNOW AMOUNTS LOOK TO RANGE FROM 2 TO PERHAPS 6 INCHES ACROSS THESE COUNTIES WITH THE MOST NORTH BUT WITH OPEN COUNTRY AND 35 MPH WINDS WITH FALLING SNOW VIS DOWN TO A QUARTER MILE WITH SIGNIFICANT DRIFTING LOOKS LIKELY. ALSO DECIDED TO ISSUE A WINTER STORM WATCH FOR AREAS EAST OF THE BLIZZARD WATCH OR NORTH OF A LINE FROM REDWOOD FALLS TO LITCHFIELD TO BUFFALO TO MILACA TO MORA FROM 12Z SUNDAY TO 12Z MONDAY. WINDS ARE AGAIN THE MAIN CONCERN BUT SHOULD BE OF LOWER SPEEDS THAN IN THE BLIZZARD WATCH AREA. SNOW AMOUNTS AGAIN LOOK TO BE FROM 2 TO 5 OR MAYBE 6 INCHES WITH THE HIGHEST AMOUNTS IN THE NORTHERN PORTION OF THE WATCH AREA BUT CONSIDERABLE BLOWING IS EXPECTED. THERE IS UNCERTAINTY OF THE DRY SLOT AND SOME POSSIBLE FLUCTUATIONS IN THE TRACK DUE TO VARIATIONS IN THE HANDLING OF THE UPPER LOW WHICH HAS YET TO COME ONSHORE WHICH MAY RESULT IN THIS WATCH BEING A BIT TOO FAR SOUTH. OTHER COMPLICATING FACTOR IS MIXED PRECIP SATURDAY NIGHT. AT THIS POINT FEEL THAT AMOUNTS WILL BE LIGHT...BUT COULD REACH ADVISORY LEVELS. NOT ENOUGH CERTAINTY RELATIVE TO THE SNOW/WIND SUNDAY TO CARRY THE WATCH SATURDAY NIGHT AS WELL. TRAVEL SUNDAY LOOKS TO BECOME VERY TREACHEROUS IF NOT IMPOSSIBLE ACROSS THE WATCH AREAS WITH THE BLOWING AND DRIFTING. SNOW WILL WRAP UP SUNDAY NIGHT BUT WINDS WILL CONTINUE TO BE STRONG THROUGH MONDAY BEFORE HIGH PRESSURE ARRIVES MONDAY NIGHT. VERY COLD AIR WILL BE IN PLACE STARTING SUNDAY NIGHT AS H85 TEMPS FALL TO COLDER THAN -20C. ANOTHER TROUGH WILL WORK INTO THE WESTERN U.S. BRINGING A RETURN OF WARM ADVECTION TUESDAY WITH ANOTHER CHANCE FOR PRECIPITATION WITH A BRIEF PERIOD OF MODERATING TEMPERATURES. THANKS TO WFOS FSD/ABR/FGF/DLH FOR THE COORDINATION THIS MORNING REGARDING THE WINTER STORM. ..MDB... && .AVIATION... /UPDATES TO 12 TAF ISSUANCE/ BAND OF MVFR CEILINGS OVER WEST CENTRAL MN AT 14Z IS EXPECTED TO EXPAND EASTWARD THIS MORNING AS A WARM FRONT LIFTS NORTH/EAST ACROSS MN. HAVE UPDATED THE 12Z TAFS TO REFLECT THE CURRENT OBSERVATIONAL TRENDS...AND THE 12Z NAM/RUC 925-850 RH PROGS. HAVE THEREFORE INCLUDED AN MVFR DECK BETWEEN 1500 AND 2500 FEET RIGHT OUT OF THE GATE FOR KAXN AND KRWF...AND INTRODUCED IT MID/LATE MORNING AT KSTC AND KMSP. EXPECT MVFR CIGS TO REACH KRNH/KEAU BY EARLY AFTERNOON. A PERIOD OF VFR CONDITIONS IS THEN EXPECTED LATE THIS AFTERNOON AND EVENING AS CLOUDS SCATTER OUT BEHIND THE FRONT. MVFR CIGS WILL THEN RE-ENTER THE TAF ON SATURDAY AS THE WINTER STORM SETS IN. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...BLIZZARD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR CHIPPEWA-LAC QUI PARLE-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR BENTON-DOUGLAS-KANABEC-KANDIYOHI-MEEKER-MILLE LACS- MORRISON-POPE-RENVILLE-SHERBURNE-STEARNS-TODD-WRIGHT. WI...NONE. && $$ LS/MDB 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 NATIONAL WEATHER SERVICE HASTINGS NE 1149 PM CST THU DEC 11 2008 .AVIATION...06Z KGRI TAF. VFR CONDITIONS REFLECTED THROUGHOUT THE FORECAST PERIOD...BUT THERE ARE A FEW THINGS TO ADDRESS. FIRST OF ALL...AT THE VERY BEGINNING OF THE PERIOD TONIGHT THERE COULD BE A LIGHT SNOW SHOWER WITH BRIEF MVFR CEILINGS. HOWEVER...WITH CLEARING SKIES LIKELY MOVING INTO THE TERMINAL WITHIN AN HOUR...HAVE OPTED TO LEAVE OUT MENTION OF THIS. THE SECOND ISSUE IS THE POSSIBILITY OF SOME SHALLOW FOG AND POSSIBLE MVFR VISIBILITY DEVELOPING BEFORE DAWN. ALTHOUGH THIS SCENARIO WAS COVERED WITH A TEMPO GROUP IN THE PREVIOUS FORECAST...AFTER SOME DEBATE HAVE DECIDED TO PULL OUT THIS TEMPO GROUP AS IT NOW SEEMS THAT BOUNDARY LAYER MIXING SHOULD REMAIN STRONG ENOUGH TO PREVENT VISIBILITIES UNDER 5 SM. OF COURSE...THIS WILL BEAR WATCHING. AFTER DAYBREAK...THE MAIN ISSUE WILL BE INCREASING SOUTHERLY BREEZES...WITH GUSTS TO AROUND 20KTS LIKELY DURING THE AFTERNOON. A SECONDARY INCREASE IN WINDS WILL LIKELY KICK UP BY LATE FRIDAY EVENING AS MIXING INCREASES UNDERNEATH A STRENGTHENING LOW LEVEL JET. && .PREV DISCUSSION... /ISSUED 947 PM CST THU DEC 11 2008/ DISCUSSION...UPDATED THE FORECAST FOR THIS EVENING. INCLUDED SOME SPRINKLES ALONG WITH FLURRIES IN THE FORECAST FOR THIS EVENING. PRECIPITATION HEADING IN FROM THE NORTH IS WANING AND WILL PROBABLY CONTINUE TO WANE AS THE NIGHT WEARS ON. ANOTHER AREA OF ECHOES SHOWING UP IN WESTERN NEBRASKA COULD MAKE ITS WAY INTO THE CENTRAL CWA LATER ON TONIGHT AS THE RIGHT REAR QUADRANT OF AN UPPER JET WILL BE NEARBY...AND COULD KICK UP SOME FLURRIES WITH A RELATIVELY NARROW AND WEAK STRAND OF MID-LEVEL FRONTOGENESIS POSSIBLE. CLIPPER TROUGH AXIS WILL BE TO THE EAST...SO NO HELP FOR PRECIPITATION PRODUCTION THERE. RAISED TEMPERATURES A BIT FOR THE NEBRASKA SIDE OF THE CWA TO KEEP EVERYONE ESSENTIALLY IN THE 20S FOR LOWS FOR FRIDAY MORNING. BOIVERIFY SUGGESTS THAT IT COULD BE A TAD WARMER BASED ON RECENT MODEL OUTPUT...PLUS WIND LOOKS LIKE IT WILL STAY UP JUST A BIT. FOG CHANCES ARE LOOKING LESS IMPRESSIVE. BUFKIT SOUNDINGS SUGGEST THAT ETA AND GFS ARE NOT GOING TO BE DEPENDABLE FOR FOG FORECASTS OVERNIGHT...BUT THE RUC LOOKS MORE REASONABLE...SUGGESTING PATCHY SHALLOW FOG AT THE MOST. PREV DISCUSSION... /ISSUED 300 PM CST THU DEC 11 2008/ SHORT TERM...FOR TONIGHT THROUGH 12Z SATURDAY. PAST MORNING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY REVEALS A DEEP UPPER TROUGH POSITIONED FROM THE HUDSON BAY REGION INTO THE LOWER MISSISSIPPI RIVER VALLEY. THIS PATTERN IS LEAVING THE PLAINS UNDER A COLD BUT PROGRESSIVE NORTHWEST FLOW REGIME ALOFT AS A 120KT UPPER JET STREAK IS SEEN DIVING SLOWLY SOUTH FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS. THE LEFT EXIT REGION OF THIS JET STREAK HAS BEEN POSITIONED ACROSS THE CENTRAL PLAINS MOST OF THE DAY. THE INDIRECT CIRCULATION ASSOCIATED WITH THE EXIT REGION...HAS ENHANCED THE MID LEVEL FRONTOGENESIS ENOUGH TO BRING A BROKEN BAND OF LIGHT SNOW/RAIN FROM THE BLACK HILLS REGION INTO SOUTH CENTRAL NEBRASKA. AS THE AREA HEADS INTO TONIGHT...THE LEFT EXIT REGION WILL CONTINUE TO SINK SLOWLY TO THE SOUTHEAST WITH BOTH THE NAM AND GFS SHOWING A BAND OF ENHANCED FRONTOGENESIS AROUND THE 800-700MB LAYER DROPPING FROM NORTH TO SOUTH ACROSS THE CWA AS WELL. ALTHOUGH MOISTURE WITH THIS SYSTEM WILL REMAIN LIMITED...CAN/T RULE OUT A CONTINUED THREAT FOR SOME ISOLATED SNOW FLURRIES THROUGH THE EVENING TO EARLY OVERNIGHT HOURS. FOR THE REMAINDER OF THE OVERNIGHT HOURS...ANTICIPATE CLOUD COVER TO ERODE OVER MOST IF NOT ALL OF THE FORECAST AREA AS SUBSIDENCE TAKES CONTROL OF THE AREA. WITH LIGHT WINDS EXPECTED AND GOOD RADIATING CONDITIONS EXISTING...APPEARS CONDITIONS WILL FAVOR AT LEAST SOME PATCHY FOG ACROSS THE AREA UNTIL SHORTLY AFTER SUNRISE ON FRIDAY. FOR FRIDAY INTO FRIDAY NIGHT...THE UPPER PATTERN TURNS MORE ZONAL AS THE UPPER TROUGH PUSHES EAST TOWARD THE EAST COAST WHILE ANOTHER WAVE DIGS INTO THE PACIFIC NORTHWEST. THE STRONGER ZONAL COMPONENT TO THE WIND FLOWING ACROSS THE ROCKIES...WILL ALLOW THE LEE TROUGH TO DEEPEN OVER THIS TIME PERIOD WITH WINDS TURNING BACK TO THE SOUTH AND INCREASING ABOVE 10 KTS. THIS SHOULD PUSH THE CORE OF THE COLDER AIR OUT OF THE REGION AS 850MB TEMPERATURES ARE SHOWN TO CLIMB ABOVE 0C. HOWEVER...THE ORIENTATION OF THE UPPER JET WILL ALLOW A PLUME OF CIRRUS TO STREAM OFF THE ROCKIES INTO THE PLAINS. THIS SHOULD LIMIT FULL MIXING/HEATING AND WILL AIM FOR HIGHS IN THE UPPER 30S TO MID 40S. LONG TERM...12Z SATURDAY THROUGH THURSDAY. FORECAST FOCUS IS ON ARRIVAL OF MUCH COLDER AIR AND INTERMITTENT CHANCES FOR LIGHT SNOW. SATURDAY MARKS THE FINAL DAY OF MILD TEMPERATURES BEFORE THE ARCTIC AIR INTRUDES. A SOUTHWEST FLOW ALOFT PREVAILS ACROSS THE REGION AHEAD OF UPPER LOW DIGGING OVER THE WESTERN CONUS. BREEZY SOUTH TO SOUTHWEST WINDS IN A TIGHTENED GRADIENT EAST OF SURFACE LOW/TROUGH THROUGH THE HIGH PLAINS ADVECT H85 TEMPS OF 6-10C INTO THE AREA...MAKING FOR A WARM DAY ALTHOUGH IT WILL BE BREEZY TO WINDY ESPECIALLY ACROSS THE SOUTHEAST CWA. THINGS THEN CHANGE QUICKLY AS STRONG COLD FRONT PUNCHES INTO THE CWA SATURDAY NIGHT...WITH ARCTIC AIR POURING SOUTH THROUGH THE DAY ON SUNDAY. HIGHS ON SUNDAY WILL BE REACHED EARLY IN THE MORNING WITH TEMPS FALLING THROUGH THE DAY PER STRONG CAA. BETTER DYNAMICS WITH MID-LEVEL WAVE LIFTING NORTHEAST OUT OF WESTERN TROUGH STAY NORTH OF THE CWA ON SUNDAY...HOWEVER A STRONG BAND OF LOW TO MID-LEVEL FRONTOGENESIS WORKS ITS WAY ACROSS THE AREA FROM NORTHWEST TO SOUTHEAST WITH SOME UPPER SUPPORT FROM LEFT EXIT REGION OF UPPER JET STREAK. THIS FORCING SHOULD BE SUFFICIENT TO PRODUCE SOME LIGHT SNOW GIVEN MOISTURE PRESENT IN THE LOWERING DENDRITIC LAYER. ANY ACCUMULATIONS AT THIS POINT LOOK TO BE LIGHT AT A HALF INCH OR LESS. MAY SEE SOME LIGHT SNOW LINGERING INTO THE EVENING AND HAVE KEPT SOME LOW POPS IN...ALTHOUGH MOST RECENT MODEL TRENDS SUGGEST A FASTER EXIT OF THIS PRECIP TO THE SOUTHEAST SO MAY BE ABLE TO CUT BACK FURTHER ON THESE SUNDAY NIGHT POPS WITH SUBSEQUENT FORECASTS. THE ARCTIC AIR IS FULLY ENTRENCHED BY MONDAY AND HIGHS ARE ONLY FORECAST TO REACH AROUND 10F NORTH TO 15F SOUTH. SHOULD BE A DRY DAY WITH SUBSIDENCE AND STRONG SURFACE RIDGE BUILDING IN BEHIND INITIAL WAVE. COLD TEMPERATURES CONTINUE THROUGH THE REMAINDER OF THE PERIOD. AFTER ANOTHER COLD DAY ON TUESDAY...WE SEE SOME SLIGHT MODERATION WEDNESDAY AND THURSDAY ALTHOUGH STILL HIGHS NOT EXPECTED TO GET OUT OF THE 20S THROUGH THIS TIME. WITH UPPER TROUGH PERSISTING OVER THE WESTERN CONUS...INTERMITTENT CHANCES FOR LIGHT SNOW CONTINUE FROM MONDAY NIGHT THROUGH THE REST OF THE PERIOD AS INDIVIDUAL SHORTWAVES ARE EJECTED FROM THE MEAN TROUGH EAST/NORTHEAST ACROSS THE REGION. WITH SUCH A COLD AIRMASS IN PLACE AND HENCE LOW DENDRITIC LAYER...IT WON/T TAKE MUCH TO SQUEEZE OUT SOME LIGHT SNOW AS THESE WAVES MOVE ACROSS. AVIATION...FOR THE 18Z KGRI TAF. VFR CONDITIONS ANTICIPATED TO CONTINUE FOR THE GRAND ISLAND TERMINAL THROUGH THE NEXT 24 HOURS. FOR THIS AFTERNOON...A FEW SNOW FLURRIES MAY SLIP PAST THE TERMINAL BUT THE COVERAGE OF ANY FLURRIES LOOKS SMALL ENOUGH TO LEAVE OUT OF THE FORECAST. OTHERWISE...LIGHT AND VARIABLE WINDS SHOULD PREVAIL THROUGH SUNSET. THE EVENING TO EARLY OVERNIGHT HOURS IS SOMEWHAT OF A CHALLENGE AS THE MODEL GUIDANCE ATTEMPTS TO LOWER CLOUD CEILINGS TO BELOW 1000 FT. HOWEVER...QUICK EXAMINATION OF REGIONAL SURFACE OBS SHOWS ONLY SOME SPOTTY PATCHES OF STRATUS WITH IFR CEILINGS. BASED ON THIS INFO...IT APPEARS AS THOUGH A DRY BOUNDARY LAYER WILL INHIBIT ANY STRATUS WITH IFR CEILINGS FROM BECOMING WIDESPREAD AND WILL OPT TO LEAVE THE CLOUD CEILING ABOVE 2000 FT. SIMILAR TO THIS AFTERNOON...A FEW SNOW FLURRIES MAY SLIP PAST THE TERMINAL AREA...BUT WITH A LOW PROBABILITY OF OCCURRING...WILL LEAVE THIS OUT OF THE FORECAST. OTHERWISE...THIS STRATUS SHOULD ERODE AFTER MIDNIGHT WITH EITHER A SCATTERED TO BROKEN CEILING NEAR 10 KFT LEFT OVER OR ALL CLOUD COVER ERODES WITH AN UNLIMITED CEILING EXPECTED. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...PFANNKUCH ne 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 BINGHAMTON NY 1225 AM EST FRI DEC 12 2008 .SYNOPSIS... A STORM SYSTEM MOVING UP THE EASTERN SEABOARD WILL CONTINUE THE WINTRY MIX OF PRECIPITATION ACROSS NORTHEASTERN PENNSYLVANIA AND CENTRAL NEW YORK TONIGHT. PRECIPITATION WILL BECOME ALL SNOW BY FRIDAY MORNING BEFORE ENDING. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL RETURN TO UPSTATE NEW YORK FRIDAY NIGHT...WITH HIGH PRESSURE AND MAINLY FAIR WEATHER SATURDAY INTO SUNDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 930 PM EST... FCST HAS BEEN A NIGHTMARE SO FAR TONIGHT. WIDESPREAD PCPN HAS OVRSPRD CWA WITH ICING FROM THE POCONOS AND CATSKILLS INTO THE SRN TIER. QUITE A BIT OF ICING BEING REPORTED ACRS SULLIVAN CNTY AND ALSO IN BRADFORD/SUSQUEHANNA WITH FAIRLY RECENT REPORTS FROM LUZERNE AND LACKAWANNA. OF COURSE...THIS IS ALL ELEVATION DRIVEN WITH VALLEYS SEEING ALL RAIN. FURTHER NORTH INTO SRN TIER...MIXING LINE HAS MADE IT TO ITHACA AND UTICA WHICH LOOKED TO BE OUT OF REACH EARLIER. THIS IS A MAJOR FLY IN THE OINTMENT AS FAR AS HEADLINES GO. HV GOTTEN SEVERAL 3-4 INCH REPORTS ON EXTREME NW PORTION OF STORM FROM HORSEHEADS TO ITHACA TO NRN OTSEGO CNTY. BUT EVEN THESE AREAS ARE MIXING AT TIMES AND PLAYING HAVOC AS TO WHAT WE THOUGHT WUD BE GOING ON AT THIS POINT. LATEST RUC ANALYSIS IS EXTREMELY DISCOURAGING WHEN VIEWING CURRENT HEADLINES. HOWEVER...GUT INSTINCT TELLS ME IT IS PROBABLY CLOSEST TO BEING RIGHT. 0C 850 LINE NOT PUSHING INTO SRN TIER UNTIL AFT 06Z. THIS IS SIGNIFICANTLY DELAYING TURNOVER TO SNOW AND IS CUTTING INTO SNOW ACCUM TIME. MODERATE FZRA OCCURRING AT BGM ALONG WITH OCNL SLEET AND A FEW FLAKES OF SNOW. THUS HV SHOVED LINE OF SNOW/SLEET AND FZRA AS FAR NORTH AS ITH...CORTLAND AND UTICA THRU 06Z WITH A TRANSITION OVR TO SNOW AFT THIS TIME AS LOPRES HEADS UP THE COAST AND WINDS GO MORE NORTHERLY BHND IT. AFT THIS POINT...SHUD SEE A TRANSITION TO SNOW AT LEAST ACRS THE SRN TIER AND INTO OTSEGO AND CHENANGO CNTYS. FURTHER SOUTH IS STILL UP FOR GRABS AS 0C LINE DOES NOT EVEN MAKE IT TO SERN ZONES UNTIL AFT 12Z WITH FZRA AND SLEET EXPECTED THRU THIS TIME. HAVING SAID THAT...FLIES CONTINUE TO CONGREGATE IN THE OINTMENT AS DRY SLOT WORKING INTO NRN VIRGINIA SHUD EFFECTIVELY SHUT MOST OF THE PCPN OFF ACRS THE ERN SXNS BTWN 09Z-12Z...JUST AS COLDEST AIR MVS IN. WILL HV TO WAIT UNTIL BTWN 12Z-18Z TO SEE WRAP-ARND PCPN ON BACKSIDE FOR POSSIBLY THE BEST CHC FOR ACCUMULATING SNOW. HV MADE MAJOR CHGS TO NR TERM GRIDS. HV ESSENTIALLY NO SNOW ACCUMS IN VALLEYS TONIGHT EXCEPT OVR CNTRL SRN TIER WHERE AREA IS IN ALL SNOW OUT TWD ELM AND TEMP SITS AT 29 DEGREES. HV ALSO TWEAKED TEMPS TO HOLD FAIRLY STEADY TONIGHT. ALSO MADE CHGS TO P-TYPES EARLY ON AND TO POPS LATER IN THE PD. UPDATED GRIDS ARE OUT. TEXT PRODUCTS WILL BE OUT SOON. PREV DISCUSSION... MIXED WINTER STORM WELL UNDERWAY WITH PRECIP STRUNG OUT UNDERNEATH POLAR JET ENTRANCE REGION TO OUR NORTH. MAIN LOW PRESSURE TRUCKING AT US...AND THINGS WILL GET WORSE. 12Z MDL GUIDANCE SEEMS TO BE LOCKED IN NOW. SIGNIFICANT QPF IN EXCESS OF AN INCH OVER NEPA...WITH ABOUT A HALF INCH EXTENDING BACK TO THE FINGER LAKES EXPECTED. PTYPE REMAINS THE MAIN HEADACHE. EXPECT BAROCLINIC ZONE AND FREEZING/FROZEN LINE TO BE FAIRLY STEADY AS MAIN SYSTEM APPROACHES. INCREASING AGEO NELY FLOW WITHIN JET ENTRANCE CIRCULATION SHOULD TEND TO DRAW COLDER AIR FROM NY SWD INTO NEPA. ANY AREAS THAT ARE MARGINALLY MIXED RIGHT NOW WILL GO OVER TO HEAVY SNOW AS FCST SOUNDINGS INDICATE ISOTHERMAL NEAR ZERO ATMOS AT BGM WHEN BEST OMEGA KICKS IN THIS EVE. SOUNDINGS ACROSS NEPA AND CATSKILLS HOLD FZRA PROFILE UNTIL LATE. IN A GENERAL SENSE...EXPECT SNOW BECOMING HEAVY NORTH OF I-88/RT-17. FZRA/IP MIX HEAVY AT TIMES OVER NRN TIER COUNTIES OF PA AND DELAWARE/SULLIVAN NY. VALLEY RAIN/MOUNTAIN FZRA EXPECTED IN NEPA. ALL PROLONGED ICING AREAS STAND TO BE IN EXCESS OF HALF INCH...WORST CASE SCENARIO UP TO AN INCH ACCRETION. BELIEVE MORE SNOW AMOUNTS WILL PILE UP NORTH OF CURRENT WARNING...SO HAVE EXTENDED ANOTHER TIER OF COUNTIES TO THE NORTH TO INCLUDE ALL OF CNTRL SRN TIER...PORTIONS OF FINGER LAKES AND THE MOHAWK VALLEY. SEE WARNING AND FCSTS FOR TOTALS. HOPE WE DIDN/T GO TOO CONSERVATIVE IN THE COLD AIR WITH BUFKIT SOUNDING AT ITH/BGM INDICATING 1.5 INCH LIQUID. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/... STORM DEPARTS FRIDAY MORNING. HAD TO INCREASE POPS FOR LINGERING SNOW SHOWERS IN A DEFORMATION ZONE SHOWING UP IN THE PROGS ACROSS EASTERN ZONES...POSSIBLY THROUGH 18Z. LAKE EFFECT DEVELOPS FOR THE MOHAWK VALLEY-SYR CORRIDOR FRIDAY AFTERNOON AND NIGHT. LOOKS QUITE UNSTABLE...BUT INVERSION HEIGHT DROPS DOWN TO BELOW 850 MB. COULDN/T SPEND TOO MUCH TIME ON THE DETAILS RIGHT NOW...BUT I HAVE A HUNCH WE MAY BE LOOKING AT ADVISORY SNOWFALL. HIGH PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY. MOS GUIDANCE TEMPS MAY NOT BE PICKING UP ON THE UPCOMING SNOW PACK...AND MAY HAVE WARMED A BIT TOO MUCH. PICKED THE COLDEST SOLUTION FOR NOW AND WILL REFINE THESE IDEAS TOMORROW. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... FOLLOWED HPC GUIDANCE FOR EXTENDED PERIOD. INITIALLY H5 RIDGE OVER NORTHEAST WILL REMAIN IN PLACE THROUGH FROPA MONDAY NIGHT THEN AREA IN MORE OF A SOUTHWEST UPPER LEVEL FLOW WITH TROF NEAR FOUR CORNERS AND SUB-TROPICAL RIDGE BUILDING ACROSS THE SE US. TEMPS WILL BE ABOVE NORMAL SUNDAY NIGHT THROUGH MONDAY NIGHT THEN CLOSER TO NORMAL REST OF PERIOD. BEST CHC FOR PRECIP LATE MONDAY THROUGH TUESDAY MORNING WITH FROPA. WEAK WAVES PASSING TO OUR SOUTH REST OF EXTENDED WILL KEEP CHC POPS FOR REMAINDER OF FORECAST ESP SOUTHERN PTN OF CWA. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... DRYSLOT RAPIDLY TAPERING PRECIP OFF FROM SOUTHWEST TO NORTHEAST ATTM...WITH SYR/RME SEEING THE HEAVIEST SNOW AND ITH/BGM/ELM TAPERING OFF WITH ITH/BGM IFR DUE TO CIGS AND ELM IMPROVING TO MVFR. RAIN IS TAPERING TO SHRA AT AVP WITH MVFR VSBYS/CIGS. SNOW MAY NOT FULLY TAPER OFF AT SYR/RME AS A BAND OF SNOW WEST OF THE DRYSLOT PULLS EAST TOWARDS DAYBREAK...LIKELY GIVING ALL SITES EXCEPT AVP ANOTHER BOUT OF IFR SN WITH AVP CHANGING TO MVFR SHSN BEFORE TAPERING OFF BY LATE MORNING. THIS SNOW BAND WILL PULL EAST OF THE AREA BY EARLY AFTERNOON WITH MVFR CIGS /IFR AT ITH-BGM/ PERSISTING THROUGH THE AFTERNOON EXCEPT IMPROVEMENT TO LOW VFR AT AVP. THIS EVENING...SOME LAKE EFFECT SHSN POSSIBLE AT SYR WITH MVFR CIGS PERSISTING OVER CNY SITES...AND AVP VFR. NORTHERLY WINDS AROUND 10KTS WILL BECOME NORTHWEST 10-15KTS THIS MORNING AND THROUGH THE DAY TODAY BEFORE DIMINISHING TO 5-10KTS THIS EVENING. OUTLOOK... SATURDAY-SUNDAY NIGHT...VFR. MONDAY...CHC MVFR SHRA...ESP IN THE AFTERNOON FOR CNY SITES AS COLD FRONT APPROACHES. MONDAY NIGHT/TUESDAY...MVFR IN SHRA CHANGING TO SHSN AS COLD FRONT PASSES THROUGH THE AREA. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR PAZ038>040-043-044-047-048-072. NY...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR NYZ009- 022>025-036-037-044>046-055>057-062. WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ015>018. && $$ SYNOPSIS...JAB/PVN NEAR TERM...PVN SHORT TERM...JAB LONG TERM...RRM AVIATION...JMA ny 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 NATIONAL WEATHER SERVICE WILMINGTON NC 655 AM EST FRI DEC 12 2008 .SYNOPSIS... COOLER AND DRIER WEATHER WILL RETURN TODAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE CENTER OF THE HIGH WILL SHIFT EAST MOVING ACROSS THE CAROLINAS THIS WEEKEND...AND WILL THEN LINGERING OFF THE MID-ATLANTIC COAST THROUGH TUESDAY WITH TEMPERATURES REBOUNDING TO ABOVE NORMAL. THE NEXT COLD FRONT WILL AFFECT THE AREA WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 4 AM FRIDAY...UPPER MEAN FLOW HAS CAUGHT THE CLOSED LOW IN THE NORTHERN GULF OF MEXICO AND HAS OPENED IT UP...AND ALREADY HAS ABSORBED A GOOD PART OF IT WITHIN THE MEAN FLOW. THIS IS ILLUSTRATED WELL USING THE LATEST WATER VAPOR IMAGERY TOPPED OVER WITH THE LATEST 12 HR RUC MODEL DATA. THE SFC LOW WAS LOCATED OVER NJ AND THE OPENED 5H S/W (REMNANT CLOSED LOW) WAS EXITTING THE TARHEEL STATE TO THE NE AT THE MOMENT. ALL MAJOR PCPN FOR THE ILM CWA IS OVERWITH. COULD OBSERVE SOME RESIDUAL LIGHT SHRA FROM ANY FORCING AND DYNAMICS FROM THE EXITING MAIN 5H S/W...HOWEVER WILL ONLY CARRY A 20-30 POP AT MOST THRU 6 AM AS NVA BECOMES MORE DOMINANT AND DEEP MOISTURE NO LONGER AVAILABLE. THE MAIN NEAR TERM DILEMMAS TO THE ILM CWA WILL BE THE PASSAGE OF A SECONDARY COLD FRONT AND/OR TROF OF LOW PRESSURE LATER THIS MORNING OR MIDDAY TODAY. INITIALLY MOISTURE WILL BE TRAPPED BELOW ROUGHLY 900MB KEEPING LOW CLOUDINESS PREVAILING THIS MORNING PRIOR TO THE 2NDRY PASSAGE. THIS ILLUSTRATED VIA MODEL SOUNDINGS OR MODEL TIME HEIGHT SECTIONS. ONCE THAT 2NDRY FRONTAL PASSAGE...WINDS AT THE LOWER LEVELS TO BECOME NW AND WILL AID IN SCOURING OUT THIS LOW LEVEL CLOUDINESS. AS A RESULT...EXPECT PTLY/MSTLY CLDY SKIES TO BECOME MSTLY SUNNY THIS AFTERNOON. THE SFC PG WILL REMAIN TIGHTENED...AND COMBINED THAT WITH COLD AIR ADVECTION ESPECIALLY MIDDAY AND THIS AFTERNOON...NW WINDS COULD GUST A BIT HIER THEN WHAT GUIDANCE IS DICTATING AT THIS TIME. FOR TONIGHT...THE LONGWAVE UPPER TROF AMPLIFIES ACROSS THE AREA AND ALLOWS FOR TEMPS THRU THE ATM COLUMN TO DROP TO NEAR OR BELOW NORMALS...AFTER HAVING BEEN WELL ABOVE THE PAST FEW DAYS. A WEAK S/W TROF TO PASS NORTH OF THE ILM CWA OVERNIGHT...WITH ASSOCIATED CLOUDINESS REMAINING JUST NORTH OF THE ILM CWA. AS FOR MAX/MIN TEMPS WILL STAY CLOSE TO GUIDANCE...BUT ERR ON THE SLITELY MILDER SIDE FOR TONIGHTS LOWS DUE TO A BOUNDARY LAYER THAT SHOULD REMAIN ACTIVE ENOUGH TO PREVENT A DECOUPLING OF THE OVERNIGHT WINDS. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY...GRADIENT FLOW WILL WEAKEN INITIALLY AS CENTER OF HIGH SHIFTS EAST AND MOVES OVERHEAD THROUGH SUNDAY MORNING. MAX CAA SHUTS OFF SAT MORNING AS HEIGHTS START RISING THROUGH THE REST OF THE SHORT TERM PERIOD PCP WATER VALUES WILL BE DOWN TO LESS THAN A QUARTER OF AN INCH SAT MORNING. OVERALL EXPECT DRY AND COLD WEATHER THROUGH MOST OF THE SHORT TERM PERIOD. WINDS WILL SHIFT FROM N TO NE AND WILL BECOME ON SHORE THROUGH SUNDAY AS HIGH PRESSURE SHIFTS OFF SHORE AND STRENGTHENS. WITH AN INCREASING ON SHORE FLOW THROUGH SUNDAY MOISTURE WILL BEGIN TO INCREASE. FOR NOW WILL KEEP FORECAST DRY...BUT COULD SEE SOME PERIODS OF CLOUDS HEADING INTO SUNDAY. TEMPS WILL START OUT BELOW CLIMO WITH PLENTY OF COLD AIR IN PLACE THROUGH MUCH OF THE WEEKEND. EXPECT TEMPS TO MAKE IT ONLY UP TO NEAR 50 SAT AFTERNOON AND BACK DOWN NEAR FREEZING BY SUN MORNING. LOW LEVEL THICKNESSES REBOUND THROUGH SUNDAY UP TO AROUND 1340. EXPECTING TEMPS TO REBOUND AS WELL UP TO NEAR 60 BY SUNDAY AFTERNOON AND CONTINUE A STEADY RISE HEADING INTO THE LONG TERM PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM FRIDAY...INCREASING RETURN FLOW SETS UP THROUGH MID WEEK AS CENTER OF HIGH CONTINUES TO SHIFT OFF SHORE AND STRENGTHEN WHILE A COLD FRONT MOVES EASTWARD. BY TUES NIGHT A COLD FRONT SHOULD MAKE IT AS FAR EAST AS THE WESTERN CAROLINAS...BUT THE FLOW AT MID LEVELS WILL REMAIN MORE PARALLEL TO THIS BOUNDARY ELIMINATING ANY STRONG PUSH TO MOVE IT THROUGH. THEREFORE NOT EXPECTING FRONT TO MAKE IT ACROSS AREA BY WED. INSTEAD HIGH PRESSURE WILL REPOSITION ITSELF OFF THE SOUTHEAST COAST WITH SOUTHERLY WINDS PERSISTING OVER THE COASTAL CAROLINAS. BY THURS THE FRONT MAY LAY ITSELF ACROSS AREA FROM THE NORTH. THE VICINITY OF COLD FRONT AND MOIST RETURN FLOW COULD END UP PRODUCING MORE IN THE WAY OF CLOUDS AND WEATHER...BUT FOR NOW PLAYED IT MORE ON THE CONSERVATIVE SIDE. TEMPS WILL CONTINUE TO MODERATE ON MONDAY AND THERE WILL BE AN OVERALL WARMING TREND THROUGH MID WEEK AS HEIGHTS RISE AND WARMER RETURN FLOW SETS UP. TEMPS SHOULD REACH WELL INTO THE 60S DURING THE DAY WITH 40S AT NIGHT. IF COLD FRONT MAKES IT THROUGH AREA ON THURSDAY TEMPS MAY DROP BACK DOWN NEAR CLIMO. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... MVFR TO POSSIBLY IFR CONDITIONS ACROSS ALL TERMINALS EXPECTED FROM 1.5K FOOT TO 2.0K FOOT CEILINGS FOR THE 1ST 4 HRS...LASTING UP TO 16Z. THIS DUE TO TRAPPED MOISTURE BELOW 900MB. A S/W TROF IN THE LOWER LEVELS...WILL LIKELY DISPERSE THIS MOISTURE UNDER NW WINDS BY MIDDAY. WITH THE REMAINDER OF THE ATM PROFILE RATHER BONE DRY...EXPECT NO ADDITIONAL CEILINGS FOR THE REMAINDER OF THE 12Z TAF ISSUANCE PERIOD. NO RESTRICTIONS TO VISIBILITIES ARE EXPECTED. ONLY PROBLEM CHILD FOR ALL AREA TERMINALS WILL BE THE GUSTY WINDS. THIS MORNING 250-270 DEGREE 15G25KT WINDS WILL VEER TO AROUND 310 DEGREES AT 15G25KT THRU DAYLIGHT IN RESPONSE TO THE PASSAGE OF A 2NDARY COLD FRONT/SFC TROF OF LOW PRESSURE. PLENTY OF ATM MIXING DUE TO COLD AIR ADVECTION WILL KEEP WINDS ON THE GUSTY SIDE. BY SUNSET...SFC WINDS TO DROP BELOW 10 KT WITH THE GUSTINESS CEASING FOR THE REMINDER OF THE NIGHT. OUTLOOK THROUGH MONDAY...VFR THROUGH SUNDAY NIGHT WITH HIGH PRESSURE FIRMLY IN CONTROL OF OUR WEATHER. BY EARLY NEXT WEEK THE HIGH SLIDES OFF THE COAST AND A FEW SHOWERS ARE POSSIBLE IN THE RETURN FLOW. IN ADDITION POSSIBLE LIGHT FOG MONDAY MORNING DUE TO THE FETCH OFF THE OCEAN. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM FRIDAY...STRONG SCA CONDITIONS EXPECTED THRU THIS EVENING. HAVE TWEAKED AND EXTENDED THE SCA BY SEVERAL HRS ACROSS ALL ZONES...MAINLY DUE TO A SLOWER RETREAT OF THE SEAS. WITH A SE-S WIND AND RESULTING FETCH THE PAST FEW DAYS TO BUILD AND AFFECT THE AREA WATERS...HAVE NOTICED A FEW TIMES THAT WW3 SOMETIMES WILL BE TOO QUICK TO SUBSIDE SEAS GIVEN THIS SCENARIO. GIVEN THIS SAME SCENARIO BUT WITH A SW WIND FETCH PRIOR TO THE COLD FRONTAL PASSAGE...I AM MORE INCLINED TO LOWER THE SEAS QUICKLY AFTER THE CFP AS WW3 DOES SO VERY WELL. WITH THE 1ST FRONTAL PASSAGE HAVING VEERED WINDS TO THE WSW...THE TASK ALREADY HAS BEGUN CUTTING DOWN THE SEAS. THIS MAY EVEN TEMPORARILY SLOW THE SEAS FROM SUBSIDING ESPECIALLY ACROSS AMZ252 WHERE A WESTERLY WIND CAN BE MAXIMIZED AND ALTHOUGH NOT AID IN BUILDING HIER SEAS AGAINST THE CURRENT SSE 9 SECOND SWELL...A WASH MACHINE TYPE SEAS WILL BE TEMPORARILY REALIZED. IN ESSENCE...SCA CRITERIA WILL LIKELY REMAIN NEEDED WITH BOTH SEAS AND LIKELY WINDS REMAINING AT OR ABOVE SCA THRESHOLDS. AS FOR THE NEXT FRONTAL PASSAGE OR TROUGH OF LOW PASSAGE OCCURS...WINDS TO FURTHER VEER TO THE NW AT 15-25 KT...AND CONTINUE TO CUT DOWN THE SEAS BY EARLY TO MID AFTERNOON TODAY. THIS TRUE OFFSHORE WIND FOR ALL COASTAL WATER ZONES...WILL FINALLY BE CUTTING DOWN SEAS BUT STILL AM SUSPECT THAT ALL SEAS WILL BE LOWER THAN SCA CRITERIA PRIOR TO SUNSET TODAY. WINDS WILL FURTHER LIGHTEN AND SLIGHTLY VEER BY 20-30 DEGREES AS THE SFC PRESSURE GRADIENT RELAXES AND THE SFC PRESSURE PATTERN BECOMES MORE CONDUCIVE FOR A NNW-N WIND DIRECTION BY SATURDAY MORNING. EXPECT ALL ADVISORY CRITERIA LOWERED BY SUNRISE SATURDAY. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY...SEAS WILL CONTINUE ON A DECREASING TREND THROUGH SATURDAY IN A WEAKENING NORTHERLY FLOW. OVERALL SEAS WILL BE IN THE 2 TO 4 FT RANGE. BY SUNDAY CENTER OF HIGH MOVES OVER THE EASTERN SEA BOARD AND SHIFTS OFF SHORE THROUGH THE DAY STRENGTHENING BY THE END OF THE PERIOD. THEREFORE WINDS WILL VEER AROUND TO E AND THEN SE BY SUNDAY NIGHT INCREASING TO AROUND 15 KTS. THESE INCREASING ON SHORE WINDS WILL PUSH SEAS UP TO 3 TO 5 FT BY SUNDAY NIGHT AND COULD BE INTO SCA CRITERIA IN THE OUTHER WATERS BY THE END OF THE PERIOD. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM FRIDAY...WINDS WILL CONTINUE TO GRADUALLY VEER AROUND TO THE SOUTH THROUGH MONDAY IN A TIGHTENED GRADIENT FLOW BETWEEN STRENGTHENING ATLANTIC HIGH PRESSURE AND A LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES. THIS PERSISTENT SOUTHERLY FLOW AROUND 15 KTS THROUGH MONDAY WILL CONTINUE TO PUSH SEAS UP TO 4 TO 6 FT. GRADIENT FLOW MAXIMIZES MONDAY NIGHT WITH THE LATEST GUIDANCE SHOWING SEAS IN THE 4 TO 7 FT RANGE OVERNIGHT. BY TUESDAY GRADIENT FLOW WEAKENS AS HIGH PRESSURE WEAKENS AND REPOSITIONS ITSELF OFF THE SOUTHEAST COAST AS LOW PRESSURE SYSTEM LIFTS OFF TO THE NE THROUGH CANADA. SEAS WILL THEN GRADUALLY DECREASE THROUGH THE DAY ON TUESDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS MORNING FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS AFTERNOON FOR AMZ250- 252. && $$ SYNOPSIS...GROSS-ZOUZIAS NEAR TERM...HOEHLER SHORT TERM...GROSS-ZOUZIAS LONG TERM...GROSS-ZOUZIAS AVIATION...HOEHLER nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 310 AM EST FRI DEC 12 2008 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE RAPIDLY AWAY TO THE NORTHEAST THIS MORNING. BEHIND THE LOW...MUCH DRIER AND COLDER AIR WILL MOVE INTO THE REGION BY LATE MORNING TO EARLY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... AS OF 200 AM FRIDAY... 05Z SFC ANALYSIS SHOWED SFC LOW PRESSURE CENTERED OVER CENTRAL NC AND SOUTHERN VA. A WARM FRONT WAS LOCATED ALONG THE NC/VA BORDER...EXTENDING NORTHEAST THROUGH SOUTHEAST VA INTO THE DELMARVA. A COLD FRONT APPROACHING THE AREA WAS LOCATED ROUGHLY FROM HICKORY NC SOUTHEAST TO FLORENCE SC. A SFC TROUGH AXIS EXTENDED FROM HICKORY NC SOUTHWEST THROUGH UPSTATE SC INTO CENTRAL GA. ALOFT...AS OF 05Z...WV IMAGERY AND RUC MODEL DATA SHOWED THE STRONG UPPER LOW CENTERED OVER UPSTATE SC. THROUGH THIS MORNING: A FAIRLY LARGE AREA OF SHOWERS ASSOC/W THE APPROACHING UPPER LOW WILL MOVE NORTHEAST ACROSS CENTRAL NC THROUGH SUNRISE THIS MORNING. THIS ACTIVITY IS EXPECTED TO BE PRIMARILY IN THE FORM OF LIGHT TO MODERATE SHOWERS...ALTHOUGH SCT HEAVY SHOWERS AND AN ISOLD THUNDERSTORM CANNOT BE RULED OUT AS MID-LEVEL LAPSE RATES STEEPEN AND DYNAMIC FORCING STRENGTHENS IN ASSOC/W THE APPROACHING UPPER LOW. AS THE SFC AND UPPER LEVEL LOW MOVE NORTHEAST THROUGH CENTRAL NC...THE SFC COLD FRONT WILL BEGIN TO SURGE EASTWARD...AND COLD ADVECTION WILL COMMENCE IN EARNEST AFTER 09Z. EXPECT TEMPS TO FALL INTO THE MID 40S IN THE WESTERN HALF OF THE AREA BY 12Z...WITH THE EASTERN HALF OF THE AREA FALLING INTO THE UPPER 40S TO LOWER 50S BY 12-15Z. ONCE COLD ADVECTION COMMENCES AND TEMPS/DEWPOINTS BEGIN TO FALL BEHIND THE FRONT...WINDS WILL PICK UP OUT OF THE NORTHWEST AT 10 TO 20 MPH...WITH GUSTS AS HIGH AS 30 MPH. THE BREEZIEST CONDITIONS TODAY SHOULD OCCUR BEFORE NOON...WHEN THE PRESSURE GRADIENT BEHIND THE DEPARTING LOW WILL BE THE TIGHTEST. THIS AFTERNOON/EVENING: THERE WILL BE A PERIOD OF STRONG SUBSIDENCE ALOFT FROM MID MORNING THROUGH EARLY AFTERNOON BEHIND THE DEPARTING UPPER LOW...HOWEVER... AN UPPER LEVEL SHORTWAVE IS EXPECTED TO AMPLIFY AND DIG SOUTHEAST THROUGH THE TN/OH VALLEYS THIS MORNING...CROSSING EAST/ESE OVER CENTRAL NC (WITH A 30-35/S VORTMAX) LATER THIS AFT AND EVE. FCST SOUNDINGS SHOW NO SATURATION WHAT-SO-EVER IN ASSOC/W THE SHORTWAVE PASSAGE THIS EVENING...AND WITH ONGOING (ALBEIT WEAKENING) COLD ADVECTION / NORTHWEST FLOW IN THE LOWER LEVELS...THINK IT WOULD BE TOUGH TO GET MUCH CLOUD COVER (OTHER THAN FEW/SCT DIURNAL CU) IN ASSOC/W THE PASSAGE OF THE SHORTWAVE DUE TO THE PRESENCE OF A PRETTY DRY LOW LEVEL AIRMASS AND SOME CANCELLATION OF THE QG FORCING ASSOC/W THE SHORTWAVE. TEMPS SHOULD STRUGGLE TO RISE MUCH THIS AFTERNOON WITH COLD ADVECTION ONGOING...AND WILL FCST HIGHS RANGING FROM THE UPPER 40S IN THE WEST/NW PIEDMONT TO THE LOWER/MID 50S IN THE EAST. TONIGHT: THE AMPLIFIED SHORTWAVE WILL PASS EAST OF THE AREA BY 06Z TONIGHT... WITH PRONOUNCED SUBSIDENCE ALOFT AND SFC HIGH PRESSURE MOVING INTO THE AREA FROM THE WEST BY OR SHORTLY AFTER SUNRISE SAT MORNING. THEREFORE...EXPECT A TREND OF CLEARING SKIES TONIGHT (ALTHOUGH THERE SHOULD`T BE TOO MUCH CLOUD COVER TO BEGIN WITH)...WITH WINDS BECOMING LIGHT/VARIABLE OR NORTHERLY AT 3-5 KT BY SUNRISE. WILL BASE LOW TEMPS CLOSE TO MOS GUIDANCE...RANGING FROM THE MID 20S IN THE WEST (WHERE LIGHT/VARIABLE WIND OR CALM CONDITIONS ARE LIKELY BY 09-12Z) TO THE LOWER 30S IN THE SOUTHEAST. -VINCENT && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 230 AM FRIDAY... HIGH PRESSURE WILL SETTLE OVER THE AREA SATURDAY AFTERNOON. ABUNDANT SUNSHINE WILL ALLOW HIGHS TO REACH INTO THE 40S WITH SOME LOWER 50S ACROSS THE SOUTH AND EAST. DEPENDING ON YOUR MODEL CHOICE... THERE COULD BE SOME HIGH LEVEL CLOUDS MOVE ACROSS THE REGION AS INDICATED BY THE GFS... WHILE THE NAM IS DRY. WILL BANK ON THE DRIER MODEL... WHICH WILL ALLOW FOR RADIATION... UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS. LOWS WILL RANGE FROM 25 TO 32. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY... THE HIGH PRESSURE AREA MOVES NORTHEAST OFF THE ATLANTIC SEABOARD... WINDS WILL SHIFT TO THE SOUTHEAST INCREASING MOISTURE OVER THE AREA. THERE IS ALSO SOME DISAGREEMENT IN THE AMOUNT OF LOW LEVEL CLOUDINESS... THE GFS BEING THE WETTER OF THE MODELS. THERE IS ALSO SOME INDICATION THE POSSIBILITY OF SOME LIGHT RAIN/DRIZZLE OVER THE WEST DUE TO THE UPSLOPE FLOW LATE SUNDAY INTO MONDAY... HOWEVER WILL HOLD OFF AT THE PRESENT TIME. HIGHS SUNDAY WILL BE IN THE 50S ...WARMING INTO THE UPPER 50S TO LOWER 60S MONDAY. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST LATE MONDAY INTO TUESDAY INCREASING THE CHANCE FOR RAIN. THE FRONT WILL LINGER SOUTH OF THE AREA TUESDAY NIGHT... BEFORE BEING PUSHED BACK NORTH AS A WARM FRONT WEDNESDAY. THE FRONT WILL FINALLY PUSH SOUTH THROUGH THE REGION THURSDAY AS HIGH PRESSURE OVER THE GREAT LAKES RIDGES SOUTH THROUGH THE NORTHEAST CONUS. THE TIMING OF THE PRECIPITATION WILL DEPEND ON THE STRENGTH AND MOVEMENT OF THESE SYSTEM... SO POPS WILL BE KEPT LOW AT THE PRESENT TIME. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 200 AM THURSDAY... PERIODS OF MVFR/IFR CEILINGS AND VISBYS WILL REMAIN POSSIBLE THROUGH 12Z THIS MORNING IN PRECIPITATION ASSOC/W THE POTENT UPPER LOW MOVING NORTHEAST ACROSS CENTRAL NC. CEILINGS/VISBYS WILL BEGIN TO IMPROVE BY OR SHORTLY AFTER SUNRISE FROM WEST TO EAST IN ASSOC/W LOW LEVEL COLD ADVECTION AND SUBSIDENCE ALOFT BEHIND THE DEPARTING UPPER LOW. THIS MEANS THAT FAY/RWI SHOULD BE THE LAST TAF SITES TO IMPROVE THIS MORNING. VFR CONDITIONS WILL RULE FROM MID MORNING THROUGH THE END OF THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME SUSTAINED AT 10-20 MPH WITH GUSTS UP TO 30 MPH ONCE COLD ADVECTION BEGINS THIS MORNING (AFTER 09Z AT KINT/KGSO...AFTER 12Z AT KFAY/KRDU/KRWI). NORTHWEST WINDS SHOULD DECREASE TO AROUND 10 KT BY LATE AFTERNOON...BECOMING LIGHT VARIABLE OR LIGHT NORTHERLY TONIGHT AS SFC HIGH PRESSURE BUILDS TOWARD THE AREA FROM THE WEST. HIGH PRESSURE BUILDS IN WITH VFR CONDITIONS EXPECTED SATURDAY. HOWEVER...AS THE HIGH MOVES OFF TO THE NORTHEAST AND WARM AIR ADVECTION BEGINS AGAIN...PERIODS OF LOW CLOUDS...ESPECIALLY LATE SUNDAY NIGHT INTO MONDAY MORNING...AND AGAIN MONDAY NIGHT INTO TUESDAY MORNING...COULD OCCUR. ANY PRECIPITATION...MOSTLY IN THE FORM OF DRIZZLE WITH THE BETTER CHANCE IN THE WEST...IS EXPECTED TO BE VERY LIGHT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...RHJ 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 GRAND FORKS ND 222 PM CST FRI DEC 12 2008 .SHORT TERM... /TONIGHT THROUGH MON/ THE FOCUS FOR THE SHORT TERM WILL BE THE WELL ADVERTISED BLIZZARD EVENT EXPECTED TO STRIKE THE NORTHERN TIER SATURDAY AND SUNDAY. FOR TONIGHT...THE RUC40 IS SHOWING SOME WEAK FRONTOGENETIC FORCING RESPONSIBLE FOR BRINGING SCATTERED SNOW SHOWERS TO PARTS OF NORTHWEST MINNESOTA. WOULD EXPECT LIGHT ACCUMULATIONS OF LESS THAN ONE HALF OF AN INCH. RUC PROGS FORCING OUT OF AREA AFT 00Z...SO TOOK LIKELY POPS OUT BETWEEN 00Z AND 03Z. FOR SAT NIGHT AND SUNDAY...BOTH THE NAM AND GFS 290K ISENTROPIC SFCS ARE SHOWING NEARLY 100 MB OF LIFT ACROSS THE AREA SAT EVENING...HOWEVER THE GFS SATURATES THE COLUMN MUCH QUICKER THAN THE NAM. GENERALLY FOLLOWING A GFS SOLUTION. THE 12Z GFS SHOWS FAIRLY HEFTY Q VECTOR CONVERGENCE ACROSS THE ENTIRE CWA BY LATE SUN AFTN AND DECENT UPPER LEVEL DIVERGENCE MID DAY SUNDAY...THUS MODELS CONTINUE TO SHOW SIGNIFICANT LIFT FROM SAT EVENING THROUGH EARLY MONDAY MORNING. ALSO WILL SEE SIG WAA ALOFT COUPLED WITH STRONG COLD ADVECTION AT THE SFC THROUGHOUT THE DAY ON SUNDAY. FOR WIND CONSIDERATIONS...ADIABATIC LAYER IS NOT ALL THAT DEEP AND H925 WINDS AVAILABLE FOR MIXING RANGE FROM 30 TO 35 KNOTS. HOWEVER...LOOKING FOR NEARLY A 24 MB PRESSURE GRADIENT ACROSS THE CWA AND FULLY EXPECT WIND GUSTS IN THE 40 TO 45 MPH RANGE DURING THE DAY SUNDAY. THUS...STORM CONTINUES TO LOOK LIKE BLIZZARD CONDS WILL OCCUR OVER MAJORITY OF CWA OUTSIDE FORESTED AREAS IN THE FAR EAST. EXPECTED WIDESPREAD HEAVY...BLOWING AND DRIFTING SNOW ESP ON SUNDAY. USING HPC QPF VALUES...LOOKS LIKE SNOW ACCUMULATIONS BY MONDAY MORNING COULD BE IN THE 8 TO 12 INCH RANGE IN THE VALLEY AND SLIGHTLY HIGHER IN THE EAST AND NORTHEAST. ASSUMING 00Z MODEL RUNS CONTINUE WITH THE EXCELLENT CONSISTENCY...WILL LIKELY UPGRADE TO A BLIZZARD WARNING WITH 4 AM PACKAGE. SYSTEM PULLS OUT AND PRECIP SHOULD PULL OFF TO THE NORTHEAST BY NOON MONDAY...HOWEVER 10 TO 15 MPH NORTHWEST WINDS SHOULD KEEP SOME BLOWING AND DRIFTING GOING THROUGH LATE MONDAY AFTERNOON. .LONG TERM... /TUE THROUGH FRI/ MODELS IN DECENT AGREEMENT. GENERAL ZONAL FLOW...WITH VERY COLD AIRMASS TO BEGIN THE PERIOD. AIRMASS LOOKS TO REMAIN COLD UNTIL THE VERY END OF THIS PERIOD. THERE IS SOME CONSISTENCY WITH A WAVE TO BRUSH THE SE FA ON TUE...AND WILL LEAVE SLIGHT POPS. OTHERWISE...LOOKS FAIRLY DRY AS COLD AIRMASS TRANSLATES TO DRY AIRMASS. && .AVIATION... BAND OF SNOW WHICH MOVED THROUGH KGFK AND KTVF WILL BE EAST OF KBJI BY 02Z. CIGS WILL GRADUALLY LOWER TONIGHT AHEAD OF APPROACHING STORM SYSTEM. EXPECT MVFR CIGS BY SAT MORNING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...BLIZZARD WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY NIGHT FOR NDZ006>008-014>016-024-026>030-038-039-049-052>054. MN...BLIZZARD WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY NIGHT FOR MNZ001>005-007-008-013>015-022-027-029-030-040. WINTER STORM WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY NIGHT FOR MNZ006-009-016-017-023-024-028-031-032. && $$ SPEICHER/TG 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 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 BLACKSBURG VA 447 AM EST FRI DEC 12 2008 .SYNOPSIS... LOW PRESSURE ALONG THE EAST COAST WILL RAPIDLY MOVE NORTHEAST AND AWAY FROM THE AREA TODAY. AN UPPER LEVEL DISTURBANCE TRAILING THIS SYSTEM WILL PASS ACROSS THE MOUNTAINS RESULTING IN LINGERING MOUNTIAN SNOW SHOWERS AND FLURRIES THROUGH TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY WITH DRY WEATHER FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... GENERALLY FOLLOWING THE 12KM NAM/LOCAL WRF/RUC THROUGH 1ST 12 HOURS. THE WRF ESPECIALLY HAS BEEN DOING A PRETTY GOOD JOB WITH THE LOCATION OF PRECIP. GIVEN THIS...LOOKING AT RAIN ENDING EARLY THIS MORNING OUT EAST WITH THE DEFORMATION ZONE SNOW PULLING NORTHEASTWARD AWAY FROM THE FAR SW ZONES. WILL SEE SOME SNOW MAINLY IN THE MTNS OF SE WV...WHERE UP TO 3 INCHES POSSIBLE ON THE HIGHEST RIDGES OF GREENBRIER. OTHERWISE...A GENERAL 1-2 INCH AMOUNT THERE. SHOULD SEE A TRANSITION TO ISOLATED/SCATTERED SNOW SHOWERS AS NW FLOW KICKS IN BEHIND DEPARTING UPPER TROUGH SHEARING NORTHEAST INTO THE MID ATLANTIC. SHORTWAVE MOVING EAST ACROSS THE MID MISSISSIPPI/LOWER OH VLY WILL KEEP THE SNOW SHOWERS AROUND THROUGH THE DAY IN FAVORED UPSLOPE AREAS...BUT NOTHING MAJOR. THIS WAVE WILL MOVE EAST INTO THE NC BY THIS EVENING WITH SNOW SHOWERS DIMINISHING AFTER MIDNIGHT. LOOKING AT ADDITIONAL 1 INCH AMOUNTS ON WRN SLOPES. WINDS TODAY WILL BE UNDER ADVISORY LEVELS...WITH GUSTS TO 40 MPH POSSIBLE THIS MORNIGN ALONG THE BLUE RIDGE IN NC/SW VA. TEMPS TODAY TRICKY WITH ONGOING COLD AIR ADVECTION. GENERALLY RAN WITH 3 HOURLY TEMP BLENDS FROM THE 12KM NAM/21Z SREF. OVERALL...SHOULD SEE HIGHS TODAY IN THE WEST WHAT THE TEMPS ARE AROUND 12-15Z. SOME DOWNSLOPE CLEARING/COMPRESSION WILL BUMP TEMPS UP A FEW DEGREES OUT EAST. TONIGHT...THE GRADIENT RELAXES TOWARD MORNING...AND TEMPS SHOULD DROP DOWN COLDER THAN MAV IN THE WEST...CLOSE TO MAV OUT EAST. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... HIGH PRESSURE WILL BE CENTERED OVERHEADY SATURDAY WITH LIGHT WINDS AND MAINLY CLEAR SKIES. TEMPERATURES WILL REMAIN COOL PER COLD NATURE OF AIRMASS. SATURDAY NIGHTS FORECAST TEMPS ARE A BIT OF A CHALLENGE. AS THE SURFACE HIGH SLIDES EAST...WARM AIR ADVECTION CLOUDINESS WILL BE ON THE INCREASE. THIS MAY COUNTER ANY SIGNIFICANT RADIATIONAL COOLING. ATTM WILL STICK PRETTY CLOSE TO MOS AND WILL NOT HEDGE EITHER WAY. HIGH PRESSURE WILL SLOWLY LOSE ITS GRIP ACROSS THE AREA ON SUNDAY AS THE CENTER OF THE HIGH SHIFTS INTO NEW ENGLAND. THIS WILL ALLOW FOR FLOW ACROSS THE REGION TO GRADUALLY BECOME MORE SOUTHEAST...AND HEIGHTS TO BEGIN TO BUILD. RETURN LOW LEVEL MOISTURE IS PROGGED TO CREEP NORTHWARD ALONG THE SPINE OF THE APPALACHIANS SUNDAY NIGHT AS SOUTHEAST WINDS INCREASE. SHALLOWNESS OF THE MOISTURE SUGGESTS ANY PRECIP THREAT WILL BE IN THE FORM OF DRIZZLE AND MAINLY ALONG THE BLUE RIDGE WHERE OROGRAPHIC LIFT MAY HELP TO SATURATE LOW LEVELS. TEMPS WILL BE ON THE RISE PER WARMING THICKNESSES...SO NO PRECIPITATION TYPE ISSUES ARE ANTICIPATED. FOR SUNDAY FOLLOWED THE COOLER NAM MOS. THE GFS MOS LOOKED TOO WARM PER INCREASING CLOUD COVER. && .LONG TERM /MONDAY THROUGH THURSDAY/... A COLD FRONT WILL APPROACH AND THEN MOVE INTO AND STALL OVER THE AREA. WE SHOULD CONTINUE TO SEE MODERATING TEMPERATURES THROUGH THIS PERIOD AS HEIGHTS CONTINUE TO RISE IN ADVANCE OF THE FRONT...AND ALSO EXPECT SCATTERED TO NUMEROUS SHOWERS ACROSS THE REGION...ESPECIALLY TUESDAY INTO WEDNESDAY. WITH TIMING QUESTIONS DAY 6 AND BEYOND...I HAVE KEPT POPS CHANCE FOR NOW. COLD AIR WILL ALSO BE FILTERING INTO THE AREA BEHIND THE FRONT...SO WE MAY SEE SOME SNOW SHOWERS IN THE MTNS BEGINNING TUESDAY NIGHT...AND THEN AGAIN WEDNESDAY NIGHT. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING...IFR/MOUNTAINS OBSCURATIONS. POOR FLYING CONDITIONS IN GENERAL EXPECTED WITH LOW CLOUDS AND RAIN THRU TONIGHT. LOW PRESSURE WILL CONTINUE TO LIFT NE AND FINALLY EXIT THE AREA LATER TONIGHT INTO EARLY FRIDAY. DEEP MOISTURE ASSOCIATED WITH THIS SYSTEM WILL RESULT IN CONTINUED PERIODIC RAINFALL ALONG WITH IFR/LIFR CIGS THRU MUCH EAST OF THE BLUE RIDGE. SNOW IS BEGINNING TO MOVE INTO SE WV AND WILL BE KEEPING CIGS/VSBYS DOWN FOR A FEW HOURS THIS MORNING...BEFORE THE SYSTEM SWINGS NORTHEAST TRANSITIONING IT TO LIGHT FLURRIES BY DAWN. WINDS WILL PICK UP THROUGH THE MORNING BEHIND DEPARTING LOW WITH GUSTS UP TO 25 TO 30 KNOTS OVER THE MTNS...INCLUDING ROANOKE. CONDITIONS AT ROA...LYH AND DAN WILL BE IMPROVING ON A COLD NORTHWEST FLOW BY EARLY FRIDAY MORNING AS THE AREA OF LOW PRESSURE MOVES EAST OF THE AREA. FOR BLF/LWB...MTN SNOW SHOWERS WILL CONTINUE WITH MVFR...POSSIBLY IFR CONDITIONS PERSISTING THROUGH THE MORNING HOURS FRIDAY....WITH SOME IMPROVEMENT BY THE AFTERNOON ESPECIALLY AT LWB. HIGH PRESSURE IS EXPECTED TO BUILD OVER THE AREA THIS WEEKEND WITH RETURN TO VFR CONDITIONS SATURDAY INTO MONDAY. ANOTHER COLD FRONT MAY IMPACT THE AREA WITH MORE SHOWERS AND POSSIBLE MVFR CONDITIONS ON TUE. && .HYDROLOGY... A RIVER FLOOD WARNING FOR SOUTH BOSTON REMAINS IN EFFECT FOR MINOR FLOODING TODAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...PM LONG TERM...DS/JJ AVIATION...JH/WP HYDROLOGY...PM va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 202 AM EST FRI DEC 12 2008 .SYNOPSIS... STRONG LOW PRESSURE WILL MOVE NORTHEAST ALONG THE VIRGINIA NORTH CAROLINA BORDER OVERNIGHT...AND PASS NORTHEAST OFF THE MID ATLANTIC COAST BY FRIDAY MORNING. AN UPPER LEVEL DISTURBANCE TRAILING THIS SYSTEM WILL PASS ACROSS THE MOUNTAINS BY FRIDAY MORNING RESULTING IN A PERIOD OF SNOW. HIGH PRESSURE WILL BUILD INTO THE REGION FRIDAY NIGHT AND SATURDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LAST BATCH OF HEAVY RAINS WITH SFC/UPPER LOW MOVING OVER SOUTHSIDE VA/NW NC PIEDMONT AND SHOULD BE EAST OF HERE BY 12Z. KEPT HIGHEST POPS OUT THAT WAY UNTIL THEN...WITH DRY SLOTTING KEEPING IT DRY IN BETWEEN THIS AND THE DEFORMATION ZONE SNOW OVER THE CENTRAL APPS INTO THE NE TN. STILL LOOKING AT MAINLY SNOW IN SE WV...INTO THE MTNS OF SW VA THROUGH 12Z...THEN TAPERING OFF. ACCUMULATIONS SHOULD STAY BELOW ADVISORY CRITERIA WITH GENERAL 1-3 INCH AMOUNTS AT HIGHEST ELEVATIONS...WITH NO MORE THAN A DUSTING ACROSS THE VALLEYS. TEMPERATURES BEGINNING TO DROP IN THE WEST...AND WILL MAKE INROADS INTO THE PIEDMONT AROUND 12Z. WINDS HAVE ALSO PICKED UP AS THE SFC LOW BEGINS TRACKING SLOWLY EAST...WITH IT PICKING UP SPEED. THE 03Z RUC/LOCAL WRF SEEM TO BE HANDLING CURRENT SITUATION BEST. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... THE SURFACE LOW WILL BE MOVING AWAY FROM THE AREA FRIDAY MORNING...AND ALL PRECIPITATION IS EXPECTED TO END QUICKER THAN EARLIER FCST. EVEN IN THE MTNS WHERE THERE WILL BE SOME UPSLOPE FLOW AND COLD ADVECTION...THE MOISTURE IS SHALLOW ENOUGH THAT ANY SNOW SHOWERS IN THE MORNING WILL BE LIGHT AND BRIEF. STILL AN UPPER LEVEL DISTURBANCE PROGGED TO MOVE ACROSS THE OHIO VALLEY DURING THE AFTERNOON AND CROSS OUR FORECAST AREA EARLY FRIDAY NIGHT. THERE MAY BE A PERIOD OF MOUNTAIN SNOW SHOWERS AND FLURRIES WITH THIS DISTURBANCE...BUT MOISTURE ASSOCIATED WITH THIS SYSTEM LOOKS PRETTY SCANT. HAVE KEPT POPS CHANCE...AND MAINLY ON THE WESTERN SLOPES FRIDAY AFTERNOON AND EVENING. ANY SNOW ACCUMS WOULD LIKELY BE JUST A FEW INCHES OR LESS FROM THIS. COLD AIR ADVECTION FRIDAY WILL RESULT IN NEARLY STEADY TEMPS... ESPECIALLY MOUNTAINS WHERE CLOUDS WILL PERSIST. HIGH PRESSURE WILL BUILD ACROSS THE AREA FROM THE WEST FRIDAY NIGHT INTO SATURDAY. SKIES SHOULD CLEAR...AND WITH SOME MOUNTAIN SNOW COVER...SATURDAY MORNING TEMPS SHOULD SLIP INTO THE TEENS AND 20S. SATURDAY WILL HAVE THE HIGH PRESSURE OVERHEAD BRINGING PLENTY OF SUN...BUT WITH A CHILLY AIRMASS IN PLACE TO KEEP HIGH TEMPS IN THE UPPER 30S TO MID 40S. SHOULD BE ANOTHER GOOD RADIATION NIGHT SATURDAY NIGHT...SO HAVE STILL KEPT LOW TEMPS COOLER THAN GUIDANCE. && .LONG TERM /SUNDAY THROUGH THURSDAY/... HIGH PRESSURE WILL SLOWLY LOSE ITS GRIP ACROSS THE AREA ON SUNDAY AS THE CENTER OF THE HIGH SHIFTS INTO NEW ENGLAND. THIS WILL ALLOW FOR FLOW ACROSS THE REGION TO GRADUALLY BECOME MORE SOUTHEAST...AND HEIGHTS TO BEGIN TO BUILD. RETURN MOISTURE MAY GENERATE SOME SHOWERS ALONG THE BLUE RIDGE IN FAR SW VA AND NW NC SUNDAY NIGHT. SUNDAY SHOULD BE A BIT WARMER THAN SATURDAY. MONDAY INTO WEDNESDAY...A COLD FRONT WILL APPROACH AND THEN MOVE INTO AND STALL OVER THE AREA. WE SHOULD CONTINUE TO SEE MODERATING TEMPERATURES THROUGH THIS PERIOD AS HEIGHTS CONTINUE TO RISE IN ADVANCE OF THE FRONT...AND ALSO EXPECT SCATTERED TO NUMEROUS SHOWERS ACROSS THE REGION...ESPECIALLY TUESDAY INTO WEDNESDAY. WITH TIMING QUESTIONS DAY 6 AND BEYOND...I HAVE KEPT POPS CHANCE FOR NOW. COLD AIR WILL ALSO BE FILTERING INTO THE AREA BEHIND THE FRONT...SO WE MAY SEE SOME SNOW SHOWERS IN THE MTNS BEGINNING TUESDAY NIGHT...AND THEN AGAIN WEDNESDAY NIGHT. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING...IFR/MOUNTAINS OBSCURATIONS. POOR FLYING CONDITIONS IN GENERAL EXPECTED WITH LOW CLOUDS AND RAIN THRU TONIGHT. LOW PRESSURE WILL CONTINUE TO LIFT NE AND FINALLY EXIT THE AREA LATER TONIGHT INTO EARLY FRIDAY. DEEP MOISTURE ASSOCIATED WITH THIS SYSTEM WILL RESULT IN CONTINUED PERIODIC RAINFALL ALONG WITH IFR/LIFR CIGS THRU MUCH EAST OF THE BLUE RIDGE. SNOW IS BEGINNING TO MOVE INTO SE WV AND WILL BE KEEPING CIGS/VSBYS DOWN FOR A FEW HOURS THIS MORNING...BEFORE THE SYSTEM SWINGS NORTHEAST TRANSITIONING IT TO LIGHT FLURRIES BY DAWN. WINDS WILL PICK UP THROUGH THE MORNING BEHIND DEPARTING LOW WITH GUSTS UP TO 25 TO 30 KNOTS OVER THE MTNS...INCLUDING ROANOKE. CONDITIONS AT ROA...LYH AND DAN WILL BE IMPROVING ON A COLD NORTHWEST FLOW BY EARLY FRIDAY MORNING AS THE AREA OF LOW PRESSURE MOVES EAST OF THE AREA. FOR BLF/LWB...MTN SNOW SHOWERS WILL CONTINUE WITH MVFR...POSSIBLY IFR CONDITIONS PERSISTING THROUGH THE MORNING HOURS FRIDAY....WITH SOME IMPROVEMENT BY THE AFTERNOON ESPECIALLY AT LWB. HIGH PRESSURE IS EXPECTED TO BUILD OVER THE AREA THIS WEEKEND WITH RETURN TO VFR CONDITIONS SATURDAY INTO MONDAY. ANOTHER COLD FRONT MAY IMPACT THE AREA WITH MORE SHOWERS AND POSSIBLE MVFR CONDITIONS ON TUE. && .HYDROLOGY... RAINFALL SO FAR HAS RANGED FROM ONE TO THREE INCHES ACROSS MUCH OF THE REGION. A RIVER FLOOD WARNING FOR SOUTH BOSTON REMAINS IN EFFECT FOR MINOR FLOODING EXPECTED FRIDAY EVENING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/WP SHORT TERM...JJ LONG TERM...DS/JJ AVIATION...JH/WP HYDROLOGY... va 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 NATIONAL WEATHER SERVICE DES MOINES IA 318 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...14/06Z MAIN CONCERN CONT TO BE WITH THE POTENTIAL FORMATION OF ST AND DZ. INIT SOUNDINGS WERE QUITE DRY AT 00Z/14 AND WILL DELAY THE ONSET OF IFR CONDS DUE TO THE DRYNESS TO OVERCOME. EXPECT TO SEE A SUDDEN DVLPMT OF LO ST BR AND DZ OVER SERN AND NRN IA AFT 09Z OR SO. VERY SLOW IMPVMT ON SUN UNTIL FROPA. CDFNT SHUD REACH KMCW-KDSM AREA AROUND MID DAY AND PASS EAST OF THE TAF SITES TWD 00Z/15. EXPECT MVFR CIGS POST FROPA WITH SGT WNWLY WINDS. && .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...BSS LONG TERM...REV AVIATION...BSS ia 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...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 NATIONAL WEATHER SERVICE RALEIGH NC 500 AM 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 TODAY AND TONIGHT...RESULTING IN AN INCREASE IN CLOUD COVER...AND A CHANCE FOR LIGHT RAIN BY MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 145 AM SUNDAY... SFC ANALYSIS THIS MORNING SHOWED 1035 MB HIGH PRESSURE CENTERED JUST OFFSHORE THE MID-ATLANTIC...WITH A SFC RIDGE AXIS EXTENDING SOUTHWEST INTO THE CAROLINAS. ALOFT...THE LATEST WV IMAGERY AND RUC MODEL DATA SHOW WSW FLOW ALOFT OVER THE CAROLINAS AND MID-ATLANTIC. TODAY: EXTENSIVE MID/UPPER LEVEL CLOUD COVER OVER THE AREA WILL MOVE EAST OF CENTRAL NC BY SUNRISE. HOWEVER...EXTENSIVE MID/UPPER LEVEL CLOUD COVER REMAINS UPSTREAM OVER TX AND THE DEEP SOUTH...AND WITH WSW FLOW ALOFT...EXPECT MORE MID/UPPER LEVEL CLOUDS TO MOVE INTO THE AREA BY LATE MORNING TO EARLY AFTERNOON. WARM ADVECTION REALLY BEGINS TO KICK IN AFTER SUNRISE TODAY AS THE SFC HIGH MOVES FURTHER OFFSHORE AND LOW LEVEL FLOW BECOMES SOUTHERLY/SOUTHEASTERLY. THIS WILL RESULT IN A RAPID INCREASE IN LOW STRATUS ACROSS PORTIONS OF THE AREA...ESPECIALLY IN THE WESTERN PIEDMONT ADJACENT TO THE FOOTHILLS WHERE UPSLOPE FLOW WILL SERVE TO LOCALLY ENHANCE LIFT. THUS...EXPECT OVERCAST CONDITIONS IN THE WESTERN PIEDMONT BY MID MORNING TO NOON...WITH MOSTLY CLOUDY SKIES ELSEWHERE DUE TO A COMBINATION OF SCT/BKN LOW STRATUS AND TRANSIENT MID/UPPER LEVEL CLOUD COVER. W/REGARD TO POPS...EVEN THOUGH BOTH THE GFS/NAM CRANK OUT A FEW HUNDREDTHS OF AN INCH ACROSS THE FAR WESTERN PIEDMONT BETWEEN 18-00Z (GFS ACTUALLY CRANKS OUT A TENTH OF AN INCH IN THE TRIAD)...STILL THINK THAT SATURATION SHOULD BE TOO SHALLOW FOR THE EFFICIENT PRODUCTION OF PRECIPITATION VIA COLLISION/COALESCENCE... WHICH WOULD ARGUE FOR NO MORE THAN DRIZZLE OR A FEW SPRINKLES DURING THE AFTERNOON. A CAVEAT TO THIS IS THAT GFS/NAM FCST SOUNDINGS SHOW LOW LEVEL SOUTHERLY FLOW INCREASING TO 35-40 KT BY MID/LATE AFTERNOON...AND THIS MAY BE STRONG ENOUGH TO ALLOW SOME LIGHT RAIN TO DEVELOP ADJACENT TO THE FOOTHILLS (I.E. NEAR THE TRIAD). IF THIS DID OCCUR...THE TRIAD COULD SEE A FEW HUNDREDTHS...ALTHOUGH THE BEST CHANCE FOR MEASURABLE RAIN WOULD STILL BE FURTHER WEST TOWARD STATESVILLE AND HICKORY. WILL CONTINUE TO MENTION ONLY PATCHY DRIZZLE THIS AFTERNOON IN THE FAR WESTERN PIEDMONT. HIGH TEMPS TODAY SOMEWHAT DIFFICULT WITH STRENGTHENING WARM ADVECTION AND VARIABLE CLOUD COVER OVER PORTIONS OF THE AREA. THE LOWEST TEMPS ARE EXPECTED IN THE TRIAD/WESTERN PIEDMONT WHERE THICKNESSES ARE LOWEST AND LOW CLOUD COVER SHOULD BE QUITE PERVASIVE...AND WILL SHOW HIGHS IN THE MID 40S IN THAT AREA. ELSEWHERE...EXPECT HIGHS TO MAKE IT INTO THE 50S...WITH TEMPS AS HIGH AS 58-62F IN THE SE COASTAL PLAIN. TONIGHT: EXPECT MOSTLY CLOUDY TO OVERCAST CONDITIONS ACROSS THE AREA TONIGHT 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. BASED ON THE REASONING MENTIONED IN THE `TODAY` DISCUSSION...WILL CONTINUE TO MENTION 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 TO THE UPPER 40S TO LOWER 50S IN THE EAST/SE COASTAL PLAIN. -VINCENT && .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. -BLAES && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 325 PM... 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. -BLAES && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 500 AM SUNDAY... 12Z SUN THROUGH 12Z MON: VFR CONDITIONS WILL CONTINUE THROUGH EARLY/MID MORNING WITH ONLY TRANSIENT MID/UPPER LEVEL CLOUD COVER ACROSS THE AREA. HOWEVER...BY MID MORNING...STRENGTHENING WARM ADVECTION AND LOW LEVEL SOUTHEASTERLY FLOW WILL ALLOW LOW STRATUS TO QUICKLY DEVELOP ACROSS THE AREA...PREDOMINATELY IN THE FAR WESTERN PIEDMONT/TRIAD AREA. EXPECT MVFR/IFR CEILINGS TO DEVELOP BY 14-17Z AT THE KINT/KGSO TAF SITES...WITH THE POSSIBILITY OF PRIMARILY MVFR CEILINGS ELSEWHERE. LIFR CEILINGS CANNOT BE RULED OUT AT THE KINT/KGSO TAF SITES LATE THIS MORNING THROUGH THE REMAINDER OF THE TAF PERIOD. WITH LOW LEVEL SOUTHERLY FLOW FURTHER STRENGTHENING TONIGHT...WE WILL LIKELY SEE A THREAT OF LOW LEVEL WIND SHEAR AFTER SUNSET DUE TO EXCELLENT DIRECTIONAL/SPEED SHEAR IN THE LOWEST 2 KFT. THE THREAT OF LLWS WILL BE MOST PRONOUNCED AT THE KINT/KGSO TAF SITES WHERE FCST SOUNDINGS SHOW A STRONG INVERSION/STABLE LAYER IN THE LOWEST FEW KFT. ELSEWHERE...THE LLWS THREAT IS NOT AS CLEAR...BUT THE IMPORTANT THING TO REMEMBER IS THAT IT CANNOT BE RULED OUT...AND THE THREAT WILL ULTIMATELY DEPEND ON HOW MUCH MIXING IS PRESENT IN THE LOWEST FEW KFT AT THE KRDU/KFAY/KRWI TAF SITES. MONDAY THROUGH THURSDAY: ADVERSE AVIATION CONDITIONS IN MVFR/IFR CEILINGS SHOULD PERSIST MONDAY THROUGH TUESDAY AS A COLD FRONT APPROACHES AND STALLS JUST WEST OF THE AREA. THE THREAT OF LOW LEVEL WIND SHEAR (PRIMARILY AT KINT/KGSO) SHOULD PERSIST THROUGH AT LEAST SUNRISE MON MORNING... ABATING BY LATE MORNING OR EARLY MON AFTERNOON WHEN FCST SOUNDINGS SHOW ENOUGH MIXING TO END THE THREAT. DEPENDING ON HOW MUCH WE MIX MON AFTERNOON...WE COULD SEE RATHER BREEZY CONDITIONS...WITH SOUTH/SW WINDS SUSTAINED AT 10-20 MPH GUSTING UP TO 30 MPH...BASED ON FCST SOUNDINGS AND THE EXPECTED STRENGTH OF LOW LEVEL FLOW. ISOLD SHOWER ACTIVITY CANNOT BE RULED OUT MONDAY AFTERNOON THROUGH TUESDAY. UNSETTLED WEATHER IS EXPECTED TO CONTINUE WEDNESDAY INTO THURSDAY. SW FLOW ALOFT WILL PERSIST...WHICH WILL ADVECT MID/UPPER LEVEL MOISTURE INTO THE REGION. IN THE LOWER LEVELS...A COLD FRONT WILL MOVE SLUGGISHLY SOUTHWARD THROUGH THE REGION CAUSING A THREAT OF MVFR/IFR CEILINGS AND/OR VISIBILITY IN RAIN. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...BLAES LONG TERM...BLAES AVIATION...VINCENT nc 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 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 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 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 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...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 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...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...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 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 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 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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tx