Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/12/13


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1053 PM MST SAT FEB 9 2013 .UPDATE AND CORRECTION... && .SHORT TERM...THE UPPER TROUGH OVER WESTERN COLORADO EARLIER TODAY JUMPED THE DIVIDE LATE THIS AFTERNOON AND CONSEQUENTLY SPLIT INTO TWO CIRCULATION CENTERS. AT THE PRESENT TIME ONE WAS POSITIONED OVER SOUTHEAST WYOMING...THE OTHER OVER SOUTHEAST COLORADO. AT THE SURFACE...A DEEP LOW FORMED OVER EL PASO AND SOUTHERN LINCOLN COUNTIES LATE THIS AFTERNOON AND HAS SINCE SHIFTED NORTHEASTWARD TO NEAR MCCOOK IN EXTREME SOUTHWEST NEBRASKA. EARLIER THIS EVENING A BAND OF MODERATE SNOWFALL STRETCHING NORTHEAST ACROSS LINCOLN... WASHINGTON AND PHILLIPS COUNTIES AS THE SFC LOW TRACKED NORTHEAST. THIS LINE OF PCPN HAS SINCE SHIFTED EAST INTO KANSAS/SWRN NEBRASKA WHERE IT IGNITED INTO A LINE OF THUNDERSTORMS EARLY THIS EVENING. LATEST RUN OF THE RAP AND NAM MODELS SHOW THIS SFC LOW TRACKING VERY SLOWLY NORTHWARD ACROSS SWRN NEBRASKA DURING THE NEXT SEVERAL HOURS. THE RESULTING TIGHT PRESSURE GRADIENT AROUND THIS DEEPENING LOW IS EXPECTED TO GENERATE STRONG NORTH-NORTHWEST SFC WINDS ACROSS THE NORTHEAST COLORADO...BEGINNING NOT LONG AFTER MIDNIGHT. WITH LITTLE OR NO SNOW ON THE GROUND YET...BLIZZARD CONDITIONS OBVIOUSLY HAVE NOT DEVELOPED YET. HOWEVER...MODELS SHOW A RESURGENCE IN PCPN ACROSS THE NERN CORNER OF THE STATE IN THE NEXT FEW HOURS AS THE UPPER LOW IN SERN COLORADO ROTATES NORTHWARD. SO BLIZZARD CONDITIONS ARE STILL EXPECTED TO DEVELOP. THEREFORE ZONES 48..49...50 AND 51 REMAIN UNDER A BLIZZARD WARNING. MEANWHILE THE UPPER LOW OVER SOUTHEAST WYOMING IS PROGGED TO ROTATES SOUTHWESTWARD OVER NORTHWEST COLORADO DURING THE NEXT SEVERAL HOURS. AS IT DOES...SHOULD SEE SNOWFALL ON THE INCREASE IN THE MOUNTAINS AND HIGH VALLEYS OF NORTH CENTRAL COLORADO. NEW SNOW AMOUNTS BY MIDDAY SUNDAY EXPECTED TO RANGE FROM 4-7 INCHES IN MTN AREAS ROUGHLY NORTH OF I-70 AND 2-5 INCH TOTALS SOUTH OF THERE...WITH LIGHTER AMOUNTS ON VALLEY FLOORS. SHOULD ALSO SEE GUSTY NORTHWEST WINDS OVER THE HIGHER TERRAIN LATER TONIGHT AND SUNDAY MORNING CAUSING AREAS OF BLOWING SNOW. THUS...THE WINTER WEATHER ADVISORY FOR SNOW AND BLOWING WAS ALLOWED TO CONTINUE FOR MTN ZONES 31...33 AND 34. AS FOR THE BLIZZARD WARNING IN NORTHEAST COLORADO...THOUGHT BEST TO DROP ZONES 42 AND 44 FROM THE WARNING AS IT NOW APPEARS THESE ZONES WILL SEE LITTLE SNOW ACCUMULATION. ALSO DROPPED THE WINTER WEATHER ADVISORY FOR ZONES 45 AND 46 FOR THE SAME REASON. .AVIATION...AT THIS HOUR (05Z) SNOWFALL WAS PRETTY MUCH OVER IN THE DENVER METRO AREA. HOWEVER COULD SEE ANOTHER BATCH OF LIGHT SNOW CURRENTLY UP ALONG THE WYOMING BORDER NORTH OF FORT COLLINS SLIDING SOUTH ALONG THE FRONT RANGE IN THE NEXT FEW HOURS. NOT EXPECTING MUCH IF ANY ACCUMULATION WITH THIS LAST WAVE OF SNOW. HOWEVER LIFR AND IFR CEILINGS LIKELY TO REMAIN OVER THE DENVER METRO AREA FOR MUCH OF THE NIGHT WITH THE LOWER CEILINGS ACCOMPANYING THE LIGHT PRECIPITATION. NORTH-NORTHWEST SFC WINDS OF 07-14KTS ARE FORECAST TO STEADILY INCREASE REST OF THE TONIGHT WITH SUSTAINED WINDS OF 12-22KT AND HIGHER GUSTS TO AROUND 30KTS GENERALLY EAST OF I-25. THESE GUSTY NORTHERLY WINDS LIKELY TO CONTINUE FOR MUCH OF SUNDAY AS CEILINGS CONTINUE TO RISE WITH DRIER AIR SLIDING DOWN FROM WYOMING ON THE BACK SIDE OF THE EXITING LOW PRESSURE SYSTEM. BY LATE IN THE DAY...THERE IS A CHANCE OF SNOW AT BJC AND APA AIRPORTS WITH LOW LEVEL UPSLOPE WINDS ALONG THE FRONT RANGE. DO NOT EXPECT TO SEE ANY SNOW AT DIA DURING THE DAY. && .PREV DISCUSSION... /ISSUED 303 PM MST SAT FEB 9 2013/ SHORT TERM...ONLY MINOR CHANGES THIS AFTERNOON. THE CIRCULATION AT THE SOUTH END OF THE TROUGH REMAINS SLIGHTLY SOUTH OF WHERE IT WAS EXPECTED TO BE...AND THE 18Z NAM COMES ALONG WITH A SIMILAR SOUTHWARD ADJUSTMENT OF PERHAPS 40 MILES...ADDING CONFIDENCE TO THE CHANGES MADE THIS MORNING. IT COMES UP WITH A MORE REASONABLE INTENSITY TO ITS SNOWBAND WHICH SNOW STRETCHES ALONG THE PLAINS FROM LIMON TO JULESBURG. WE WILL STICK WITH OUR PREVIOUS SNOW FORECAST WHICH HAS THOSE DETAILS COMPROMISED BETWEEN SEVERAL MODEL RUNS...BUT GENERALLY LIGHT FROM GREELEY AND DENVER WESTWARD WITH ABOUT 4 INCHES THROUGH FORT MORGAN AND DIA AND THEN UP TO 8 INCHES OUT IN THE NORTHEAST CORNER. STILL POTENTIAL FOR MORE SOMEWHERE IF WE DO GET A CONCENTRATED SLOW MOVING BAND FOR A WHILE...BUT THE 4 TO 8 IN GENERAL SHOULD BE FINE. WIND ALSO JUST A LITTLE STRONGER WITH THE LATEST MODEL RUNS. NUDGING THINGS SOUTHWARD GIVES HIGHER CONFIDENCE TO ENOUGH SNOW/WIND FOR AN ADVISORY FOR THE STRETCH FROM BENNETT TO LIMON. THE PART OF SOUTHERN WELD COUNTY EAST OF HIGHWAY 85...AND WESTERN ELBERT/SOUTHERN DOUGLAS COUNTY COULD ALSO HAVE A FAIR AMOUNT OF BLOWING SNOW...IF THERE IS ENOUGH SNOWFALL. MEANWHILE THE AREA FROM DENVER NORTHWARD WILL HAVE TO GET ITS SNOW IN THE NEXT 6 HOURS OR SO AS THE CONVECTIVE BLOB GOES BY...THEN THE DOWNSLOPING SHOULD OVERRIDE THE WEAKER LIFT THAT WILL BE LEFT. THE SNOW WILL LIKELY BE JUST ABOUT DONE ON SUNDAY MORNING THOUGH THERE COULD STILL BE A LITTLE ALONG THE EASTERN BORDER. THE WIND WILL BE EASING IN THE WEST...BUT COULD BE SLOW TO COME DOWN IN THE EAST. EXPECT THAT CONDITIONS WILL BE IMPROVING IN THE NORTHEAST CORNER IN THE AFTERNOON...BUT IF SNOWFALL IS TOWARD THE HIGHER END OF OUR RANGE THEN VISIBILITIES COULD STILL BE PRETTY BAD. LONG TERM...AN UPPER LEVEL TROUGH DROPPING SOUTH OUT OF THE NORTHERN RCOKIES WILL BE CENTERED OVER THE GREAT BASIN SUNDAY NIGHT. AS THIS TROUGH SINKS SOUTH...IT WILL SPREAD LIFT AND MOISTURE OVER WESTERN AND CENTRAL COLORADO SUNDAY NIGHT AND MONDAY. FORCING AND MOISTURE NOT GREAT...BUT ENOUGH TO PRODUCE LIGHT SNOW OVER THE MOUNTAINS AND SOUTHERN FOOTHILLS. SOME UPSLOPE DEVELOPS WITH THIS SYSTEM...SO THERE COULD BE A LITTLE LIGHT SNOW ALONG THE FRONT RANGE. THE BEST CHANCE BEING ALONG THE PALMER DIVIDE. SNOW WILL COME TO AN END MONDAY NIGHT AS THE TROUGH SHIFTS SOUTHEAST ACROSS THE SOUTHERN ROCKIES. A WEAK RIDGE EMBEDDED IN A NORTHWEST FLOW ALOFT WILL MOVE ACROSS COLORADO TUESDAY NIGHT AND EARLY WEDNESDAY. THIS WILL BRING MILDER TEMPERATURES AND DRY CONDITIONS. THIS WILL BE SHORT LIVED AS THE NEXT SHORT WAVE TROUGH DROPS SOUTH OUT OF THE NORTHERN ROCKIES. THIS SYSTEM WILL PUSH A COLD FRONT TROUGH COLORADO RESULTING IN COOLER TEMPERATURES FOR THURSDAY AND FRIDAY. A LOT OF DIFFERENCES AMONG THE MODELS. MOST OF THEM INDICATE MOISTURE WILL BE LIMITED WITH THIS SYSTEM. FOR NOW...WILL KEEP THE MENTION OF SNOW CONFINED TO THE HIGHER TERRAIN FOR WEDNESDAY NIGHT THROUGH FRIDAY. SATURDAY WILL BE MILD AND DRY AS THIS TROUGH MOVES OFF TO THE EAST AND THE NEXT RIDGE FORMS OVER THE REGION. AVIATION...SNOW SHOWERS THROUGH MID EVENING...IT IS NOW LOOKING LIKE THE STRONGER INTENSITIES MAY BE BEFORE 00Z RATHER THEN AFTER. IN ANY EVENT THERE WILL BE PERIODS OF IFR CONDITIONS THROUGH 04Z AND THEY MAY PREVAIL FOR SEVERAL HOURS. HEAVIER SHOWERS MAY PRODUCE 1/2 MILE VISIBILITIES BUT ONLY FOR SHORT LENGTHS OF TIME. AFTER 04Z CEILINGS AND VISIBILITIES WILL IMPROVE ALTHOUGH INSTRUMENT APPROACHES MAY BE NEEDED TO KDEN THROUGH THE NIGHT. ON SUNDAY NORTHWEST WINDS WILL CONTINUE WITH GUSTS IN THE 20 TO 30 KNOT RANGE...SOME UNCERTAINTY ABOUT HOW HIGH THE CEILINGS WILL BE BUT PROBABLY HIGH ENOUGH FOR VISUAL APPROACHES TO KDEN. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING UNTIL 5 PM MST SUNDAY FOR COZ048>051. WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR COZ031-033- 034. && $$ SHORT TERM...BAKER/GIMMESTAD LONG TERM....MEIER AVIATION...BAKER/GIMMESTAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1041 PM MST SAT FEB 9 2013 .UPDATE... && .SHORT TERM...THE UPPER TROUGH OVER WESTERN COLORADO EARLIER TODAY JUMPED THE DIVIDE LATE THIS AFTERNOON AND CONSEQUENTLY SPLIT INTO TWO CIRCULATION CENTERED. AT THE PRESENT TIME ONE WAS POSITIONED OVER SOUTHWEST WYOMING..THE OTHER OVER SOUTHEAST COLORADO. AT THE SURFACE...A DEEP LOW FORMED OVER EL PASO AND LINCOLN COUNTIES LATE THIS AFTERNOON AND HAS SINCE SHIFTS NORTHEASTWARD TO MCCOOK IN EXTREME SOUTHWEST NEBRASKA. EARLIER THIS EVENING SAW A BAND OF MODERATE SNOWFALL ON RADAR STRETCHED ACROSS LINCOLN COUNTY UP ACROSS WASHINGTON AND PHILLIPS COUNTIES IN THE VICINITY OF THIS SFC LOW. SINCE THEN...THIS LINE OF PCPN HAS SHIFTED EAST INTO KANSAS/SWRN NEBRASKA WHERE IT IGNITED INTO A LINE OF THUNDERSTORMS. LATE RUN OF THE RAP AND NAM MODELS SHOW THIS SFC LOW TRACKING VERY SLOWLY NORTHWARD ACROSS SWRN NEBRASKA NEXT SEVERAL HOURS. THE RESULTING TIGHT PRESSURE GRADIENT AROUND THIS DEEPENING LOW IS EXPECTED TO GENERATE STRONG NORTH-NORTHWEST SFC WINDS ACROSS THE NORTHEAST CORNER OF COLORADO...BEGINNING SOMETIME AFTER MIDNIGHT. OF COURSE WITH LITTLE OR NO SNOW ON THE GROUND OUT THERE YET...NOT LIKELY WE/LL SEE BLIZZARD CONDITIONS. HOWEVER...MODELS SHOW A RESURGENCE IN PCPN ACROSS THE NERN CORNER OF THE STATE IN THE NEXT FEW HOURS AS THE UPPER LOW IN SERN COLORADO ROTATES NORTHWARD. MEANWHILE THE UPPER LOW OVER SOUTHEAST WYOMING IS PROGGED TO ROTATES SOUTHWESTWARD OVER NORTHWEST COLORADO DURING THE NEXT SEVERAL HOURS. AS IT DOES... SHOULD SEE SNOWFALL ON THE INCREASE IN THE MOUNTAINS AND HIGH VALLEYS OF NORTH CENTRAL COLORADO. NEW SNOW AMOUNTS BY MIDDAY SUNDAY EXPECTED TO RANGE FROM 4-7 INCHES IN MTN AREAS ROUGHLY NORTH OF I-70 AND 2-5 INCH TOTALS SOUTH OF THERE...WITH LIGHTER AMOUNTS ON VALLEY FLOORS. SHOULD ALSO SEE GUSTY NORTHWEST WINDS OVER THE HIGHER TERRAIN LATER TONIGHT AND SUNDAY MORNING CAUSING AREAS OF BLOWING SNOW. THUS...THE WINTER WEATHER ADVISORY FOR SNOW AND BLOWING WAS ALLOWED TO CONTINUE FOR MTN ZONES 31...33 AND 34. AS FOR THE BLIZZARD WARNING IN NORTHEAST COLORADO... THOUGHT BEST TO DROP ZONES 42 AND 44 FROM THE WARNING AS IT NOW APPEARS THESE ZONES WILL SEE LITTLE SNOW ACCUMULATION. ALSO DROPPED THE WINTER WEATHER ADVISORY FOR ZONES 45 AND 46 FOR THE SAME REASON. .AVIATION...AT THIS HOUR (05Z) SNOWFALL WAS PRETTY MUCH OVER IN THEDENVER METRO AREA. HOWEVER COULD SEE ANOTHER BATCH OF LIGHT SNOW CURRENTLY UP ALONG THE WYOMING BORDER NORTH OF FORT COLLINS SLIDING SOUTH ALONG THE FRONT RANGE IN THE NEXT FEW HOURS. NOT EXPECTING MUCH IF ANY ACCUMULATION WITH THIS LAST WAVE OF SNOW. HOWEVER LIFR AND IFR CEILINGS LIKELY TO REMAIN OVER THE DENVER METRO AREA FOR MUCH OF THE NIGHT WITH THE LOWER CEILINGS ACCOMPANYING THE LIGHT PRECIPITATION. NORTH-NORTHWEST SFC WINDS OF 07-14KTS ARE FORECAST TO STEADILY INCREASE REST OF THE TONIGHT WITH SUSTAINED WINDS OF 12-22KT AND HIGHER GUSTS TO AROUND 30KTS GENERALLY EAST OF I-25. THESE GUSTY NORTHERLY WINDS LIKELY TO CONTINUE FOR MUCH OF SUNDAY AS CEILINGS CONTINUE TO RISE WITH DRIER AIR SLIDING DOWN FROM WYOMING ON THE BACK SIDE OF THE EXITING LOW PRESSURE SYSTEM. BY LATE IN THE DAY...THERE IS A CHANCE OF SNOW AT BJC AND APA AIRPORTS WITH LOW LEVEL UPSLOPE WINDS ALONG THE FRONT RANGE. DO NOT EXPECT TO SEE ANY SNOW AT DIA DURING THE DAY. && .PREV DISCUSSION... /ISSUED 303 PM MST SAT FEB 9 2013/ SHORT TERM...ONLY MINOR CHANGES THIS AFTERNOON. THE CIRCULATION AT THE SOUTH END OF THE TROUGH REMAINS SLIGHTLY SOUTH OF WHERE IT WAS EXPECTED TO BE...AND THE 18Z NAM COMES ALONG WITH A SIMILAR SOUTHWARD ADJUSTMENT OF PERHAPS 40 MILES...ADDING CONFIDENCE TO THE CHANGES MADE THIS MORNING. IT COMES UP WITH A MORE REASONABLE INTENSITY TO ITS SNOWBAND WHICH SNOW STRETCHES ALONG THE PLAINS FROM LIMON TO JULESBURG. WE WILL STICK WITH OUR PREVIOUS SNOW FORECAST WHICH HAS THOSE DETAILS COMPROMISED BETWEEN SEVERAL MODEL RUNS...BUT GENERALLY LIGHT FROM GREELEY AND DENVER WESTWARD WITH ABOUT 4 INCHES THROUGH FORT MORGAN AND DIA AND THEN UP TO 8 INCHES OUT IN THE NORTHEAST CORNER. STILL POTENTIAL FOR MORE SOMEWHERE IF WE DO GET A CONCENTRATED SLOW MOVING BAND FOR A WHILE...BUT THE 4 TO 8 IN GENERAL SHOULD BE FINE. WIND ALSO JUST A LITTLE STRONGER WITH THE LATEST MODEL RUNS. NUDGING THINGS SOUTHWARD GIVES HIGHER CONFIDENCE TO ENOUGH SNOW/WIND FOR AN ADVISORY FOR THE STRETCH FROM BENNETT TO LIMON. THE PART OF SOUTHERN WELD COUNTY EAST OF HIGHWAY 85...AND WESTERN ELBERT/SOUTHERN DOUGLAS COUNTY COULD ALSO HAVE A FAIR AMOUNT OF BLOWING SNOW...IF THERE IS ENOUGH SNOWFALL. MEANWHILE THE AREA FROM DENVER NORTHWARD WILL HAVE TO GET ITS SNOW IN THE NEXT 6 HOURS OR SO AS THE CONVECTIVE BLOB GOES BY...THEN THE DOWNSLOPING SHOULD OVERRIDE THE WEAKER LIFT THAT WILL BE LEFT. THE SNOW WILL LIKELY BE JUST ABOUT DONE ON SUNDAY MORNING THOUGH THERE COULD STILL BE A LITTLE ALONG THE EASTERN BORDER. THE WIND WILL BE EASING IN THE WEST...BUT COULD BE SLOW TO COME DOWN IN THE EAST. EXPECT THAT CONDITIONS WILL BE IMPROVING IN THE NORTHEAST CORNER IN THE AFTERNOON...BUT IF SNOWFALL IS TOWARD THE HIGHER END OF OUR RANGE THEN VISIBILITIES COULD STILL BE PRETTY BAD. LONG TERM...AN UPPER LEVEL TROUGH DROPPING SOUTH OUT OF THE NORTHERN RCOKIES WILL BE CENTERED OVER THE GREAT BASIN SUNDAY NIGHT. AS THIS TROUGH SINKS SOUTH...IT WILL SPREAD LIFT AND MOISTURE OVER WESTERN AND CENTRAL COLORADO SUNDAY NIGHT AND MONDAY. FORCING AND MOISTURE NOT GREAT...BUT ENOUGH TO PRODUCE LIGHT SNOW OVER THE MOUNTAINS AND SOUTHERN FOOTHILLS. SOME UPSLOPE DEVELOPS WITH THIS SYSTEM...SO THERE COULD BE A LITTLE LIGHT SNOW ALONG THE FRONT RANGE. THE BEST CHANCE BEING ALONG THE PALMER DIVIDE. SNOW WILL COME TO AN END MONDAY NIGHT AS THE TROUGH SHIFTS SOUTHEAST ACROSS THE SOUTHERN ROCKIES. A WEAK RIDGE EMBEDDED IN A NORTHWEST FLOW ALOFT WILL MOVE ACROSS COLORADO TUESDAY NIGHT AND EARLY WEDNESDAY. THIS WILL BRING MILDER TEMPERATURES AND DRY CONDITIONS. THIS WILL BE SHORT LIVED AS THE NEXT SHORT WAVE TROUGH DROPS SOUTH OUT OF THE NORTHERN ROCKIES. THIS SYSTEM WILL PUSH A COLD FRONT TROUGH COLORADO RESULTING IN COOLER TEMPERATURES FOR THURSDAY AND FRIDAY. A LOT OF DIFFERENCES AMONG THE MODELS. MOST OF THEM INDICATE MOISTURE WILL BE LIMITED WITH THIS SYSTEM. FOR NOW...WILL KEEP THE MENTION OF SNOW CONFINED TO THE HIGHER TERRAIN FOR WEDNESDAY NIGHT THROUGH FRIDAY. SATURDAY WILL BE MILD AND DRY AS THIS TROUGH MOVES OFF TO THE EAST AND THE NEXT RIDGE FORMS OVER THE REGION. AVIATION...SNOW SHOWERS THROUGH MID EVENING...IT IS NOW LOOKING LIKE THE STRONGER INTENSITIES MAY BE BEFORE 00Z RATHER THEN AFTER. IN ANY EVENT THERE WILL BE PERIODS OF IFR CONDITIONS THROUGH 04Z AND THEY MAY PREVAIL FOR SEVERAL HOURS. HEAVIER SHOWERS MAY PRODUCE 1/2 MILE VISIBILITIES BUT ONLY FOR SHORT LENGTHS OF TIME. AFTER 04Z CEILINGS AND VISIBILITIES WILL IMPROVE ALTHOUGH INSTRUMENT APPROACHES MAY BE NEEDED TO KDEN THROUGH THE NIGHT. ON SUNDAY NORTHWEST WINDS WILL CONTINUE WITH GUSTS IN THE 20 TO 30 KNOT RANGE...SOME UNCERTAINTY ABOUT HOW HIGH THE CEILINGS WILL BE BUT PROBABLY HIGH ENOUGH FOR VISUAL APPROACHES TO KDEN. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING UNTIL 5 PM MST SUNDAY FOR COZ048>051. WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR COZ031-033- 034. && $$ SHORT TERM...BAKER/GIMMESTAD LONG TERM....MEIER AVIATION...BAKER/GIMMESTAD
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
315 AM EST SUN FEB 10 2013 .DISCUSSION... TODAY-TONIGHT... HIGH PRES RIDGE SPANNING THE LENGTH OF THE ERN SEABOARD WILL CONTINUE TO DOMINATE THE LCL WX PATTERN. THE RIDGE IS EMBEDDED WITHIN A STRONG W TO SW H85-H30 FLOW THAT WILL PUSH IT INTO THE W ATLC OVER THE NEXT 24HRS. THIS MOTION WILL FORCE SFC/LOW LVL ERLY WINDS ACRS CENTRAL FL TO VEER TO THE SE THRU THE DAY...THEN TO THE S/SE OVERNIGHT. THE INCREASING SRLY WIND COMPONENT WILL ALLOW A GRADUAL WARMING TREND TO BEGIN. AFTN MAX TEMPS IN THE M/U70S AREAWIDE...SLIGHTLY ABV AVG FOR EARLY FEB. INCREASING SRLY FLOW OVERNIGHT WILL KEEP MIN TEMPS IN THE U50S/L60S INTERIOR AND N OF THE CAPE...L/M60S SPACE AND TREASURE COASTS...ARND 10F ABV AVG. EVENING SOUNDINGS SHOW A STRONG SUBSIDENCE INVERSION THRU THE H90-H70 LYR THAT WILL EFFECTIVELY CAP VERTICAL MOTION BLO 5KFT. LATEST RAP ANALYSIS SHOWS A FAIR AMOUNT OF REMNANT FRONTAL MOISTURE LINGERING OVER THE S HALF OF THE PENINSULA...H100-H85 LYR MEAN RH VALUES BTWN 70-80PCT. RH VALUES DIMINISH UPSTREAM BUT STILL LARGELY BTWN 50-60PCT. THIS SHOULD BE ENOUGH TO ALLOW A SCT-BKN STRATOCU DECK TO FORM ACRS CENTRAL FL AFT SUNRISE THAT WILL PANCAKE AT THE BASE OF THE AFOREMENTIONED RIDGE. OVERALL MOISTURE IS TOO LOW AND THE INVERSION TOO STRONG TO ALLOW ANY SHRAS TO FORM. MONDAY...LOW LVL SOUTHERLY FLOW IN THE MORNING WILL VEER TO S-SW IN THE AFTERNOON AS A COLD FRONT MOVES TWD S GA AND THE FL PANHANDLE. SHOULD BE PARTLY SUNNY WITH HIGHS IN THE UPPER 70S ALONG THE VOLUSIA COAST TO LOWER 80S OVER THE INTERIOR. MONDAY NIGHT...LIGHT SW FLOW AHEAD OF THE NEXT FRONT AND DEWPTS IN THE 60S ALONG WITH MOSTLY CLEAR SKIES IN THE LATE EVENING WILL ALLOW LATE NIGHT FOG TO DEVELOP. THE FOG SHOULD BE MORE PREVALENT ACROSS NRN SECTIONS INCLUDING LAKE AND VOLUSIA COUNTIES. TUESDAY-TUE NIGHT...LOW LVL SOUTHERLY FLOW WILL CONTINUE WITH ANOTHER WARM AFTERNOON IN THE UPPER 70S NRN SECTIONS TO LOWER 80S SOUTH. A MID LVL DISTURBANCE ACROSS OK WILL INDUCE A LOW PRESSURE AREA TO DEVELOP ALONG THE FRONT ALONG THE NRN GULF COAST THAT WILL TRACK ENE THROUGH TUE NIGHT. AT THIS TIME IT LOOKS LIKE THE PREFRONTAL CONVECTIVE LINE WILL REMAIN ACROSS NRN FL THROUGH THE LATE NIGHT HOURS AND WILL KEEP POPS LESS THAN 20 PERCENT ACROSS NRN SECTIONS FOR NOW TUE NIGHT BASED ON 00Z MODELS. EXPECT INCREASING CLOUDINESS ACROSS NRN SECTIONS LATE TUE NIGHT WITH LOW TEMPS MILD IN THE 60S. WED...00Z MODELS ARE IN AGREEMENT THAT THE PREFRONTAL CONVECTIVE LINE WILL REACH NRN SECTIONS WED MORNING AND MOVE SE THROUGH E CENTRAL FL THROUGH THE DAY AND OFF THE TREASURE COAST BY LATE EVENING. CAPES IN THE 500-800 J/KG RANGE AND NEGATIVE LIS SHOULD SUPPORT THUNDER CHANCES WITH THE LINE ACROSS CENTRAL AND NRN SECTIONS. TRENDS SHOULD BE FOR WEAKENING THROUGH THE DAY AND WILL ONLY CARRY SLGT SHOWER CHCS LATE IN THE DAY FOR FAR SRN SECTIONS. HIGHS AHEAD OF THE FRONT WILL BE WARM IN THE LOWER 80S. WED NIGHT...THE FRONT SHOULD PASS OFF TO THE SE THROUGH THE NIGHT WITH SOME ISOLATED SHOWERS ENDING ACROSS THE TREASURE COAST BY LATE EVENING. MODELS HINTING AT SOME OVERRUNNING DEVELOPING LATE AND FOR NOW EXPECT CONSIDERABLE CLOUDINESS. THU...OLD FRONTAL BOUNDARY SHOULD ACT AS A WARM FRONT ACROSS FAR S FL WITH MID LVL OVERRUNNING EXPECT TO BRING AREAS OF LIGHT RAIN ACROSS CENTRAL AND SOUTH FL. WILL KEEP POPS IN SCATTERED RANGE THOUGH LATER FORECASTS MAY NEED TO INCREASE RAIN CHANCES WITH AREA OF STRATIFORM RAIN LIKELY MOVING IN ACROSS THE CENTRAL PENINSULA BY AFTERNOON. FRIDAY-SUNDAY...MODELS INDICATE SECONDARY CYCLOGENESIS ACROSS THE ATLC FRIDAY NE OF THE BAHAMAS WITH TRAILING FRONTAL MOISTURE ACROSS THE SRN HALF OF THE PENINSULA. THROUGH THE WEEKEND...THE LONGWAVE TROUGH WILL DEEPEN ACROSS THE ERN CONUS SHUNTING THE DEEP MOISTURE SE AWAY FROM THE AREA BY FRIDAY NIGHT AND ALLOWING A COLDER CONTINENTAL AIRMASS TO MOVE DOWN THE PENINSULA. LOOKS LIKE BELOW NORMAL TEMPS FOR THE UPCOMING WEEKEND WITH HIGHS IN THE 60S AND LOWS MAINLY IN THE 40S. && .AVIATION... THRU 11/00Z...VFR ALL SITES...BTWN 10/15Z-11/00Z E/SE SFC WND G22KTS. && .MARINE... TODAY-TONIGHT...HI PRES RIDGE APPROACHING THE ERN SEABOARD WILL MAINTAIN A FAIRLY TIGHT PGRAD OVER THE FL PENINSULA...GEOSTROPHIC APPROX CHART INDICATES SUSTAINED SFC/BNDRY LYR WNDS BTWN 15-20KTS. EARLY MRNG OBS FROM THE DATA BUOYS/C-MAN STATIONS ARE JUST BLO 15KTS...SEAS ARND 4FT AREAWIDE INCREASING TO ARND 6FT AT BUOY010. THE RIDGE AXIS WILL PUSH INTO THE W ATLC OVER THE NEXT 24HRS... ALLOWING WINDS TO VEER TO THE SE THRU THE DAY...THEN TO THE S/SE OVERNIGHT. AS THEY DO...THE HIGHER SEAS N OF THE BAHAMAS SHOULD ADVECT INTO THE LCL ATLC...ALLOWING WAVE HEIGHTS TO BUILD TO 4-6FT AREAWIDE. CAUTIONARY STATEMENTS WILL CONTINUE. SOUTHERLY WINDS TO 15 KNOTS OFFSHORE MONDAY WITH SEAS 4-6 FT WILL DECREASE TO 3-4 FT BY TUE AFTN. NEXT COLD FRONT WILL CROSS THE WATERS WED INTO WED NIGHT...WITH SW WINDS NEAR 20 KNOTS OFFSHORE AND SEAS REBUILDING TO 4-6 FT. WINDS DECREASE FROM THE NW ON THU WITH SEAS AGAIN SUBSIDING UNTIL NEXT INCREASE FROM THE NORTH NEXT WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... DAB 72 62 79 62 / 0 10 10 10 MCO 78 58 82 62 / 10 10 10 10 MLB 75 64 80 65 / 10 10 0 10 VRB 76 63 80 62 / 10 10 0 10 LEE 77 59 81 62 / 0 10 10 10 SFB 77 59 81 63 / 0 10 10 10 ORL 78 59 82 62 / 0 10 10 10 FPR 75 63 80 62 / 10 10 0 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...VOLKMER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1115 PM CST SAT FEB 9 2013 .DISCUSSION... ISSUED 835 PM CST SAT FEB 9 2013 CLOUDS CONTINUE TO INCREASE FROM SOUTHWEST TO NORTHEAST THIS EVENING AS OUR NEXT WEATHER SYSTEM...CURRENTLY OVER SOUTHWEST KANSAS...BEGINS TO LIFT NORTHEAST INTO THE CENTRAL PLAINS. PRESSURE GRADIENT BEGINNING TO TIGHTEN UP OVER THE AREA AS THE STORM BEGINS TO DEEPEN TO OUR WEST. SURFACE DEW POINTS IN THE MID TO UPPER 50S CONFINED TO CENTRAL TEXAS THIS EVENING BUT SHOULD HAVE NO PROBLEM STREAMING NORTHEAST OVERNIGHT ON THE STRENGTH OF A 40-50 KT LOW LEVEL JET. THE INITIAL BAND OF RAIN HAS STREAKED NORTHEAST TO JUST WEST OF ST. LOUIS AND SHOULD PUSH EAST OF THE MISSISSIPPI RIVER IN THE NEXT FEW HOURS AFFECTING OUR SOUTH AND WEST BY MIDNIGHT...AND THEN WILL CONTINUE TO SHIFT OVER THE REMAINDER OF THE FORECAST AREA INTO SUNDAY MORNING. LOOKS AS IF WE REACHED...OR WILL SHORTLY REACH OUR LOWS FOR THE NIGHT AS THE COMBINATION OF CLOUDS AND AN INCREASING SOUTHEAST WIND SHOULD HELP KEEP THE TEMPERATURES STEADY OR SLOWLY RISING OVERNIGHT. HAVE MADE SOME ADJUSTMENTS TO THE TIMING OF THE RAIN ACRS THE WEST AND SOUTH FOR LATER THIS EVENING. STILL THE POSSIBILITY FOR SOME ISOLD CONVECTION BUT THAT LOOKS TO BE MORE PROBABLE FOR SUNDAY MORNING IN THE 12Z-18Z TIME FRAME. SHOULD HAVE THE UPDATED ZONES OUT BY 900 PM. && .AVIATION... ISSUED 1105 PM CST SAT FEB 9 2013 FORECAST CONCERNS CONTINUE TO REVOLVE AROUND TIMING OF MVFR/IFR CIGS BACK INTO THE FORECAST AREA EITHER LATE TONIGHT OR JUST AFTER DAWN SUNDAY. ONE BAND OF RAIN WAS TRACKING NORTHEAST OVER PARTS OF WEST CENTRAL IL LATE THIS EVENING AND THAT WILL AFFECT MOST OF OUR AREA. HAD A REPORT OF SOME SLEET MIXED IN WITH THE RAIN DOWN IN STL BUT HAVE NOT SEEN ANY ADDITIONAL REPORTS OF SLEET SINCE THEN. FORECAST SOUNDINGS SHOWING A VERY NARROW WINDOW TIME FRAME WHERE SLEET MAY OCCUR BUT SIGNIFICANT WARM ADVECTION OCCURRING AHEAD OF THE STORM SYSTEM TO OUR WEST SHOULD OVERCOME ANY EVAPORATIVE COOLING THAT MAY OCCUR SO WILL CONTINUE TO GO WITH -RA/-SHRA. THE UPPER WAVE THAT IS CAUSING THIS INITIAL BAND OF PRECIP TO PUSH ACRS THE AREA WILL SHIFT EAST OF OUR AREA AFTR 08Z...WITH A SECONDARY SHORTWAVE SEEN PUSHING OUT OF THE SOUTHERN PLAINS WITH CONVECTION DEVELOPING NOW OVER OKLAHOMA NE INTO SRN KANSAS. THIS BAND SHOULD MOVE THRU THE TAF SITES IN THE 12Z-18Z TIME FRAME. MAY BE ENOUGH ELEVATED INSTABILITY TO PRODUCE SOME ISOLD CONVECTION DURING THE MORNING BUT COVERAGE LOOKS TOO LIMITED TO INCLUDE IN TAFS. FINALLY THE COLD FRONT WILL SHIFT ACRS THE AREA IN THE 21Z-00Z TIME FRAME. THERE APPEARS TO BE ENOUGH LOW LEVEL CONVERGENCE ALONG THE BOUNDARY TO KEEP AT LEAST A VCSH MENTION IN ALL THE TAF SITES UNTIL THE BOUNDARY SHIFTS EAST OF KCMI AROUND 02Z. AFTER THAT...THE BIG CONCERN WILL BE WITH WRAP AROUND CLOUDS AND STRONG GRADIENT WINDS AS THE STORM SYSTEM MOVES OFF TO OUR NORTH. WILL SLOW DOWN THE INITIAL ONSET OF MVFR CIGS FOR A FEW HOURS ACRS THE WEST AS UPSTREAM OBS NOT SHOWING MUCH IN THE WAY OF LOWER CIGS UNTIL YOU GET OUT ACRS WEST CENTRAL AND SOUTHWEST MISSOURI. MODELS CONTINUE TO SHOW THE DRY SLOW PUSHING IN EARLY IN THE AFTN WHICH WILL CUT OFF THE STEADY RAINS AND MAY ACTUALLY BRING CIGS UP TO VFR BY EVENING ACRS THE SOUTHWEST BEFORE THE WRAP AROUND MOISTURE APPROACHES THE FORECAST AREA LATE TOMORROW EVENING AND OVERNIGHT ALONG WITH THE STRONG SW WINDS. OUR SE WINDS TONIGHT WILL AVERAGE FROM 12 TO 17 KTS WITH A FEW GUSTS ARND 22KTS...THEN WINDS WILL VEER MORE INTO A SOUTHERLY DIRECTION ON SUNDAY AT 15 TO 20 KTS WITH SOME GUSTS APPRCHG 30 KTS AT TIMES. JUST AFTR FROPA LATE TOMORROW AFTN AND EVE...WINDS WILL SHIFT INTO THE SSW (200-230 DEGREES) AT 15 TO 25 KTS WITH GUSTS AOA 30 KTS. SMITH && .PREV DISCUSSION... ISSUED 210 PM CST SAT FEB 9 2013 PESKY LOW CLOUDS WHICH HAVE PLAGUED THE AREA RECENTLY FINALLY HAVE BEEN SIGNIFICANTLY ERODING OVER THE LAST SEVERAL HOURS. EARLY AFTERNOON SATELLITE IMAGERY SHOWING THEM MAINLY CONFINED TO AREAS FROM THE ILLINOIS RIVER EAST TO CHAMPAIGN...ALTHOUGH THE REST OF THESE CLOUDS SHOULD BE GONE BY LATE AFTERNOON. NOT MUCH BREAK IN THE CLOUDS EXPECTED...AS MID AND HIGH CLOUDS WERE RAPIDLY ADVANCING IN FROM THE SOUTHWEST. LARGE UPPER LOW SLOWLY ADVANCING THROUGH THE 4 CORNERS REGION AND STILL ON TARGET TO AFFECT OUR WEATHER LATE TONIGHT INTO EARLY NEXT WEEK. SHORT TERM...TONIGHT THROUGH MONDAY... MORNING MODELS REMAIN IN GOOD AGREEMENT WITH LIFTING THE UPPER LOW INTO THE UPPER MISSISSIPPI VALLEY BY SUNDAY EVENING. SHOWERS ON THE INCREASE ACROSS OKLAHOMA THIS AFTERNOON AND WILL BE ADVECTING NORTHEAST TONIGHT AHEAD OF INTENSIFYING CYCLONE OVER THE PLAINS. A LOT OF DRY AIR IN THE LOWER LEVELS NEEDS TO BE OVERCOME IN OUR AREA...BUT RAP MODEL SOUNDINGS SHOW THE COLUMN MOISTENED UP IN SPRINGFIELD BY 2 AM AND THE NORTHEASTERN CWA AROUND 4-5 AM. HAVE INTRODUCED SOME SLIGHT CHANCE POPS IN THE FAR SOUTHWEST LATE THIS EVENING...BUT HIGHER OVERNIGHT POPS REMAIN AFTER MIDNIGHT. HIGHEST POPS DURING THE PERIOD WILL BE ON SUNDAY MORNING...WITH A RAPID ENDING OF THE RAIN FROM WEST TO EAST DURING THE AFTERNOON. WILL LINGER SOME SLIGHT CHANCE POPS INTO THE EVENING EAST OF I-57. WINDS ARE ALSO A CONCERN DURING THE PERIOD. PRESSURE GRADIENT TIGHTENS OVERNIGHT AS THE SURFACE LOW LIFTS NORTHEAST TO AROUND OMAHA BY LATE SUNDAY MORNING. WILL LIKELY SEE SOME GUSTS OF AROUND 30-35 MPH LATE MORNING THROUGH MID AFTERNOON. WINDS WILL REMAIN FAIRLY BREEZY AS THEY SWING AROUND TOWARD THE SOUTHWEST OR WEST SUNDAY NIGHT...THEN GUSTS OF 30-40 MPH LIKELY AGAIN ON MONDAY. HIGHEST GUSTS SHOULD BE ALONG AND NORTH OF THE I-74 CORRIDOR... CLOSER TO THE SURFACE LOW. LONG TERM...TUESDAY THROUGH SATURDAY... SOUTHERN BRANCH OF THE JET STREAM STILL LOOKS TO BE THE ACTIVE ONE MOST OF THIS WEEK...AS ANOTHER LOW IS DUG OUT OF THE DEEP TROUGH IN THE SOUTHWEST U.S. AND MOVES EASTWARD TOWARD THE GULF COAST. LONGER RANGE MODELS KEEP ANY OVERRUNNING PRECIP JUST TO OUR SOUTH LATE TUESDAY NIGHT AND WEDNESDAY AS THE SURFACE LOW LIFTS TOWARD THE MID-ATLANTIC COAST. MAIN FEATURE OF CONCERN IN THE EXTENDED IS THE CARVING OUT OF A DEEP TROUGH OVER THE CENTER OF THE NATION LATE THIS WEEK...MARKING A PERIOD OF COLDER WEATHER WHICH WILL BEGIN FRIDAY AND LAST MUCH OF THE WEEKEND. THE GFS AND ECMWF MODELS BOTH FORM A SURFACE REFLECTION IN THE TROUGH...BUT THE GFS IS A LOT STRONGER AND FURTHER NORTH WITH ANY PRECIPITATION. SLIGHT CHANCE POPS ARE STILL WARRANTED LATE IN THE WEEK DUE TO THE UNCERTAINTY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1147 AM CST SUN FEB 10 2013 .SHORT TERM /TODAY/... ANOTHER BAND OF PRECIP DEVELOPING ACROSS SOUTHWEST IOWA INTO NORTHWEST MISSOURI WILL CONTINUE TO ADVECT NORTH NORTHEAST THROUGH THE MORNING HOURS. THIS BAND HAS DEVELOPED ALONG THE 295-300K ISENTROPIC LAYER WITH GOOD MOISTURE TRANSPORT AND THETA-E ADVECTION PRESENT. LIGHT RAIN/DRIZZLE WILL PERSIST OVER THE CENTRAL AND SOUTHWEST SECTIONS OF THE FORECAST AREA THROUGH 18Z OR SOONER BEFORE THE DRY SLOW PUNCHES INTO THE STATE LATE THIS MORNING. LOWERED POPS OVER THE SOUTHERN HALF OF THE FORECAST AREA TODAY AS A RESULT OF THE DRY SLOT. FURTHER NORTH...THE TIMING OF CURRENT MIXED PRECIP BAND AFFECTING NORTHERN IOWA LOOKS TO PUSH OUT OF THE FORECAST AREA BY AROUND 15Z THIS MORNING. WARMER AIR CONTINUES TO ADVECT INTO THE STATE AND WILL SWITCH PRECIP OVER TO ALL RAIN BY 18Z OR LIKELY EARLIER. SOUNDINGS AT ALO BECOME ALL RAIN BY 15Z...WITH MCW TEETERING BETWEEN FZRA/SN/RAIN B/T 15-18Z. THE 06Z HRRR HAS INITIALIZED WELL WITH CURRENT RADAR TRENDS AND ENDS THE BULK OF THE PRECIP BY AROUND 16Z. STILL LIKELY TO SEE LIGHT FZRA/SLEET AND EVEN SNOW MIX UNTIL THEN AND WILL KEEP ADVISORY TIMING AS IS. THE TIMING OF THE COLDER TEMPS AND WRAP-AROUND MOISTURE INTO NORTHWEST IOWA LOOKS TO BE PAST 21Z AND HAVE RAIN/SNOW MIX MENTIONED OVER THE NORTH. BUFR SOUNDINGS DEPICTING ICE INTRODUCTION BEGINNING AS EARLY AS 21Z BUT MORE LIKELY CLOSER TO 00Z MONDAY. HAVE MENTION OF SN/RA ACROSS THE NORTH PAST 21Z. .LONG TERM /TONIGHT THROUGH SATURDAY/... UPPER LOW OVER NORTHWEST IOWA AT THE BEGINNING OF THE PERIOD WILL SHIFT NORTHEAST INTO THE WESTERN GREAT LAKES BY 12Z MONDAY. THIS WILL HELP SWING A COLD FRONT THROUGH THE STATE THIS EVENING. STRONG COLD ADVECTION FROM 850-900 MB WILL DEEPEN MIXING THROUGH THE EVENING. PROXIMITY MODEL SOUNDING PROFILES REMAIN PERSISTENT WITH 40 TO 45 KTS AVAILABLE WITHIN THE MIXED LAYER AND SHOULD HAVE SOME OF THESE WINDS TRANSFER TO THE SFC IN THE FORM OF GUSTS WHILE SUSTAINED WINDS APPROACH 30 MPH FOR A PERIOD. THEREFORE CONFIDENCE IS HIGH THAT WIND ADVISORY CRITERIA WILL BE MET OVERNIGHT INTO EARLY MONDAY MORNING BEGINNING SHORTLY AFTER 00Z IN THE WEST. SOME UNCERTAINTY THOUGH ON HEADLINE TYPE OVER THE NORTH WHERE SOME SNOW IS LIKELY. ANY SNOW ACCUMULATIONS THIS EVENING ARE EXPECTED TO BE AN INCH OR LESS WHICH SHOULD NOT CAUSE A BIG PROBLEM CONSIDERING THERE IS CURRENTLY NO SNOW COVER ACROSS THE AREA. HOWEVER POTENTIAL IS THERE FOR SOME CONVECTIVE ELEMENTS TO BE ASSOCIATED WITH AN AREA OF SNOW THIS AFTERNOON INTO THE EARLY EVENING. IF THIS INDEED DOES DEVELOP AND HIGHER SNOW AMOUNTS APPROACHING 2 INCHES OCCURS...THEN THE FLAVOR OF HEADLINES ASSOCIATED WITH THE WIND WOULD NEED TO TRANSITION TO WINTER WEATHER. WITH CURRENT HEADLINE OUT THROUGH MID MORNING AND SOME UNCERTAINLY WITH TYPE ACROSS THE NORTH...HAVE OPTED TO NOT ISSUE ADDITIONAL HEADLINES FOR NOW WHICH WOULD ALLOW THE FOLLOWING SHIFT TO ACCESS TRENDS BEFORE ISSUING. THE CANADIAN UPPER WAVE WHICH WILL DIVE INTO THE TROUGH CREATED BY OUR CURRENT SYSTEM...WILL PASS TO THE SOUTH OF THE AREA TUESDAY AND TUESDAY NIGHT WITH NO SIGNIFICANT WEATHER FORECAST FOR CENTRAL IOWA. ANOTHER WAVE WILL DROP SOUTH BY WEDNESDAY NIGHT AND WILL CARVE A TROUGH OUT ACROSS THE NORTHERN PLAINS WITH ANOTHER PUSH OF COLDER AIR WITH 850 MB TEMPERATURES DROPPING TO -10C. SOME LIGHT SNOW POTENTIAL WITH THIS PASSING WAVE. SIGNIFICANT DIFFERENCES BEYOND THAT WITH THE ECMWF MORE PROGRESSIVE PUSHING THE UPPER RIDGE INTO THE WESTERN PLAINS WHILE THE GFS DETERMINISTIC AND ENSEMBLES HOLD THE NORTHWEST FLOW FOR A MORE PROLONGED PERIOD. && .AVIATION...10/18Z LOW PRESSURE JUST NORTH OF KOFK WILL MOVE TO NORTHEAST WI BY LATE TONIGHT. SOME IMPROVEMENT IN CONDITIONS ACROSS THE SOUTH HALF OF IA AS PRONOUNCED DRY SLOT PUSHES INTO THE STATE. KDSM AND KOTM WILL LIKELY SEE A SEVERAL HOUR PERIOD OF VFR CONDITIONS BEFORE THE MVFR AND IFR CONDITIONS WRAP AROUND THE BACK SIDE OF THE LOW. SELY WINDS WILL VEER TO SWLY THIS AFTERNOON. WITH THE PASSAGE OF THE LOW WNWLY WINDS WILL INCREASE WITH SURFACE GUSTS ABV 30 KTS BY MON MORNING AND WINDS OF 50 TO 60 KTS WITHIN 3000 FEET OF THE SFC. CLOUD LAYER WILL GRADUALLY LIFT MON MORNING AS WELL. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MS FEB 13 LONG TERM...DONAVON AVIATION...MS FEB 13
AREA FORECAST DISCUSSION
NWS DES MOINES IA
553 AM CST SUN FEB 10 2013 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TODAY/... ANOTHER BAND OF PRECIP DEVELOPING ACROSS SOUTHWEST IOWA INTO NORTHWEST MISSOURI WILL CONTINUE TO ADVECT NORTH NORTHEAST THROUGH THE MORNING HOURS. THIS BAND HAS DEVELOPED ALONG THE 295-300K ISENTROPIC LAYER WITH GOOD MOISTURE TRANSPORT AND THETA-E ADVECTION PRESENT. LIGHT RAIN/DRIZZLE WILL PERSIST OVER THE CENTRAL AND SOUTHWEST SECTIONS OF THE FORECAST AREA THROUGH 18Z OR SOONER BEFORE THE DRY SLOW PUNCHES INTO THE STATE LATE THIS MORNING. LOWERED POPS OVER THE SOUTHERN HALF OF THE FORECAST AREA TODAY AS A RESULT OF THE DRY SLOT. FURTHER NORTH...THE TIMING OF CURRENT MIXED PRECIP BAND AFFECTING NORTHERN IOWA LOOKS TO PUSH OUT OF THE FORECAST AREA BY AROUND 15Z THIS MORNING. WARMER AIR CONTINUES TO ADVECT INTO THE STATE AND WILL SWITCH PRECIP OVER TO ALL RAIN BY 18Z OR LIKELY EARLIER. SOUNDINGS AT ALO BECOME ALL RAIN BY 15Z...WITH MCW TEETERING BETWEEN FZRA/SN/RAIN B/T 15-18Z. THE 06Z HRRR HAS INITIALIZED WELL WITH CURRENT RADAR TRENDS AND ENDS THE BULK OF THE PRECIP BY AROUND 16Z. STILL LIKELY TO SEE LIGHT FZRA/SLEET AND EVEN SNOW MIX UNTIL THEN AND WILL KEEP ADVISORY TIMING AS IS. THE TIMING OF THE COLDER TEMPS AND WRAP-AROUND MOISTURE INTO NORTHWEST IOWA LOOKS TO BE PAST 21Z AND HAVE RAIN/SNOW MIX MENTIONED OVER THE NORTH. BUFR SOUNDINGS DEPICTING ICE INTRODUCTION BEGINNING AS EARLY AS 21Z BUT MORE LIKELY CLOSER TO 00Z MONDAY. HAVE MENTION OF SN/RA ACROSS THE NORTH PAST 21Z. .LONG TERM /TONIGHT THROUGH SATURDAY/... UPPER LOW OVER NORTHWEST IOWA AT THE BEGINNING OF THE PERIOD WILL SHIFT NORTHEAST INTO THE WESTERN GREAT LAKES BY 12Z MONDAY. THIS WILL HELP SWING A COLD FRONT THROUGH THE STATE THIS EVENING. STRONG COLD ADVECTION FROM 850-900 MB WILL DEEPEN MIXING THROUGH THE EVENING. PROXIMITY MODEL SOUNDING PROFILES REMAIN PERSISTENT WITH 40 TO 45 KTS AVAILABLE WITHIN THE MIXED LAYER AND SHOULD HAVE SOME OF THESE WINDS TRANSFER TO THE SFC IN THE FORM OF GUSTS WHILE SUSTAINED WINDS APPROACH 30 MPH FOR A PERIOD. THEREFORE CONFIDENCE IS HIGH THAT WIND ADVISORY CRITERIA WILL BE MET OVERNIGHT INTO EARLY MONDAY MORNING BEGINNING SHORTLY AFTER 00Z IN THE WEST. SOME UNCERTAINTY THOUGH ON HEADLINE TYPE OVER THE NORTH WHERE SOME SNOW IS LIKELY. ANY SNOW ACCUMULATIONS THIS EVENING ARE EXPECTED TO BE AN INCH OR LESS WHICH SHOULD NOT CAUSE A BIG PROBLEM CONSIDERING THERE IS CURRENTLY NO SNOW COVER ACROSS THE AREA. HOWEVER POTENTIAL IS THERE FOR SOME CONVECTIVE ELEMENTS TO BE ASSOCIATED WITH AN AREA OF SNOW THIS AFTERNOON INTO THE EARLY EVENING. IF THIS INDEED DOES DEVELOP AND HIGHER SNOW AMOUNTS APPROACHING 2 INCHES OCCURS...THEN THE FLAVOR OF HEADLINES ASSOCIATED WITH THE WIND WOULD NEED TO TRANSITION TO WINTER WEATHER. WITH CURRENT HEADLINE OUT THROUGH MID MORNING AND SOME UNCERTAINLY WITH TYPE ACROSS THE NORTH...HAVE OPTED TO NOT ISSUE ADDITIONAL HEADLINES FOR NOW WHICH WOULD ALLOW THE FOLLOWING SHIFT TO ACCESS TRENDS BEFORE ISSUING. THE CANADIAN UPPER WAVE WHICH WILL DIVE INTO THE TROUGH CREATED BY OUR CURRENT SYSTEM...WILL PASS TO THE SOUTH OF THE AREA TUESDAY AND TUESDAY NIGHT WITH NO SIGNIFICANT WEATHER FORECAST FOR CENTRAL IOWA. ANOTHER WAVE WILL DROP SOUTH BY WEDNESDAY NIGHT AND WILL CARVE A TROUGH OUT ACROSS THE NORTHERN PLAINS WITH ANOTHER PUSH OF COLDER AIR WITH 850 MB TEMPERATURES DROPPING TO -10C. SOME LIGHT SNOW POTENTIAL WITH THIS PASSING WAVE. SIGNIFICANT DIFFERENCES BEYOND THAT WITH THE ECMWF MORE PROGRESSIVE PUSHING THE UPPER RIDGE INTO THE WESTERN PLAINS WHILE THE GFS DETERMINISTIC AND ENSEMBLES HOLD THE NORTHWEST FLOW FOR A MORE PROLONGED PERIOD. && .AVIATION...10/12Z LIFR/IFR CIGS WILL PERSIST DURING MUCH OF THE CRITICAL TAF PERIOD AS A BAND OF DRIZZLE/LIGHT RAIN MOVES ACROSS CENTRAL IOWA. VISIBILITY WITHIN THIS BAND HAVE DROPPED TO IFR DSM/FOD WILL SEE THESE LOWER VIS THROUGH 14Z OR SO. KEPT MENTION OF FZRA AT MCW AS TEMPS STILL REMAIN BELOW FREEZING THROUGH 14Z BEFORE WARMER TEMPS MOVE INTO NORTHERN IOWA. LOW CONFIDENCE WITH LIFR/IFR CIGS TO IMPROVE UNTIL AFTER 18Z TODAY AT DSM/OTM. LEANED TOWARD THE MORE PESSIMISTIC NAM MOS AS IT KEEPS IFR CIGS THROUGH MONDAY MORNING OVER NORTHERN IOWA. LATEST HRRR MODEL RUN HAS IFR CIGS LIFT BY AROUND 21Z AT FOD...BUT KEEP ALO/MCW CIGS THROUGH THE AFTERNOON. VERY STRONG WINDS DEVELOP THIS EVENING AND LIKELY WILL SEE GUSTS OVER 30KTS OVERNIGHT TONIGHT. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ004>007-016-017. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
409 AM CST SUN FEB 10 2013 .SHORT TERM /TODAY/... ANOTHER BAND OF PRECIP DEVELOPING ACROSS SOUTHWEST IOWA INTO NORTHWEST MISSOURI WILL CONTINUE TO ADVECT NORTH NORTHEAST THROUGH THE MORNING HOURS. THIS BAND HAS DEVELOPED ALONG THE 295-300K ISENTROPIC LAYER WITH GOOD MOISTURE TRANSPORT AND THETA-E ADVECTION PRESENT. LIGHT RAIN/DRIZZLE WILL PERSIST OVER THE CENTRAL AND SOUTHWEST SECTIONS OF THE FORECAST AREA THROUGH 18Z OR SOONER BEFORE THE DRY SLOW PUNCHES INTO THE STATE LATE THIS MORNING. LOWERED POPS OVER THE SOUTHERN HALF OF THE FORECAST AREA TODAY AS A RESULT OF THE DRY SLOT. FURTHER NORTH...THE TIMING OF CURRENT MIXED PRECIP BAND AFFECTING NORTHERN IOWA LOOKS TO PUSH OUT OF THE FORECAST AREA BY AROUND 15Z THIS MORNING. WARMER AIR CONTINUES TO ADVECT INTO THE STATE AND WILL SWITCH PRECIP OVER TO ALL RAIN BY 18Z OR LIKELY EARLIER. SOUNDINGS AT ALO BECOME ALL RAIN BY 15Z...WITH MCW TEETERING BETWEEN FZRA/SN/RAIN B/T 15-18Z. THE 06Z HRRR HAS INITIALIZED WELL WITH CURRENT RADAR TRENDS AND ENDS THE BULK OF THE PRECIP BY AROUND 16Z. STILL LIKELY TO SEE LIGHT FZRA/SLEET AND EVEN SNOW MIX UNTIL THEN AND WILL KEEP ADVISORY TIMING AS IS. THE TIMING OF THE COLDER TEMPS AND WRAP-AROUND MOISTURE INTO NORTHWEST IOWA LOOKS TO BE PAST 21Z AND HAVE RAIN/SNOW MIX MENTIONED OVER THE NORTH. BUFR SOUNDINGS DEPICTING ICE INTRODUCTION BEGINNING AS EARLY AS 21Z BUT MORE LIKELY CLOSER TO 00Z MONDAY. HAVE MENTION OF SN/RA ACROSS THE NORTH PAST 21Z. .LONG TERM /TONIGHT THROUGH SATURDAY/... UPPER LOW OVER NORTHWEST IOWA AT THE BEGINNING OF THE PERIOD WILL SHIFT NORTHEAST INTO THE WESTERN GREAT LAKES BY 12Z MONDAY. THIS WILL HELP SWING A COLD FRONT THROUGH THE STATE THIS EVENING. STRONG COLD ADVECTION FROM 850-900 MB WILL DEEPEN MIXING THROUGH THE EVENING. PROXIMITY MODEL SOUNDING PROFILES REMAIN PERSISTENT WITH 40 TO 45 KTS AVAILABLE WITHIN THE MIXED LAYER AND SHOULD HAVE SOME OF THESE WINDS TRANSFER TO THE SFC IN THE FORM OF GUSTS WHILE SUSTAINED WINDS APPROACH 30 MPH FOR A PERIOD. THEREFORE CONFIDENCE IS HIGH THAT WIND ADVISORY CRITERIA WILL BE MET OVERNIGHT INTO EARLY MONDAY MORNING BEGINNING SHORTLY AFTER 00Z IN THE WEST. SOME UNCERTAINTY THOUGH ON HEADLINE TYPE OVER THE NORTH WHERE SOME SNOW IS LIKELY. ANY SNOW ACCUMULATIONS THIS EVENING ARE EXPECTED TO BE AN INCH OR LESS WHICH SHOULD NOT CAUSE A BIG PROBLEM CONSIDERING THERE IS CURRENTLY NO SNOW COVER ACROSS THE AREA. HOWEVER POTENTIAL IS THERE FOR SOME CONVECTIVE ELEMENTS TO BE ASSOCIATED WITH AN AREA OF SNOW THIS AFTERNOON INTO THE EARLY EVENING. IF THIS INDEED DOES DEVELOP AND HIGHER SNOW AMOUNTS APPROACHING 2 INCHES OCCURS...THEN THE FLAVOR OF HEADLINES ASSOCIATED WITH THE WIND WOULD NEED TO TRANSITION TO WINTER WEATHER. WITH CURRENT HEADLINE OUT THROUGH MID MORNING AND SOME UNCERTAINLY WITH TYPE ACROSS THE NORTH...HAVE OPTED TO NOT ISSUE ADDITIONAL HEADLINES FOR NOW WHICH WOULD ALLOW THE FOLLOWING SHIFT TO ACCESS TRENDS BEFORE ISSUING. THE CANADIAN UPPER WAVE WHICH WILL DIVE INTO THE TROUGH CREATED BY OUR CURRENT SYSTEM...WILL PASS TO THE SOUTH OF THE AREA TUESDAY AND TUESDAY NIGHT WITH NO SIGNIFICANT WEATHER FORECAST FOR CENTRAL IOWA. ANOTHER WAVE WILL DROP SOUTH BY WEDNESDAY NIGHT AND WILL CARVE A TROUGH OUT ACROSS THE NORTHERN PLAINS WITH ANOTHER PUSH OF COLDER AIR WITH 850 MB TEMPERATURES DROPPING TO -10C. SOME LIGHT SNOW POTENTIAL WITH THIS PASSING WAVE. SIGNIFICANT DIFFERENCES BEYOND THAT WITH THE ECMWF MORE PROGRESSIVE PUSHING THE UPPER RIDGE INTO THE WESTERN PLAINS WHILE THE GFS DETERMINISTIC AND ENSEMBLES HOLD THE NORTHWEST FLOW FOR A MORE PROLONGED PERIOD. && .AVIATION...10/06Z COMPLEX SCENARIO DURING FORECAST PACKAGE AS STRONG THETA-E ADVECTION PRODUCES LIGHT WINTRY PRECIPITATION ACROSS NORTHERN IOWA TONIGHT INTO SUNDAY MORNING. ANTICIPATE WIDESPREAD IFR CONDITIONS IN MOST LOCATION BY DAYBREAK AS CEILINGS CRASH ALONG WITH AREAS OF FREEZING RAIN...SLEET AND SNOW NORTH OF KSLB TO KALO OVERNIGHT. WARMER SURFACE TEMPERATURES WILL EDGE NORTHWARD WITH MUCH OF THE FORECAST AREA BECOMING STRAIGHT RAIN BY 12 TO 15Z WITH THE POSSIBLE EXCEPTION OF KMCW. CEILING MAY IMPROVE ACROSS SOUTHERN IOWA ON SUNDAY AS WARM SECTOR EDGES INTO THE STATE. WINDS WILL BE STRONG FROM THE SOUTH TO SOUTHEAST FOR MUCH OF THE FORECAST AS DEEP LOW PRESSURE MOVES INTO NORTHWEST IOWA. WINDS WILL BECOME WEST TO NORTHWEST TOWARD THE END OF THE FORECAST PERIOD AS A FRONT PASSES THROUGH THE STATE. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR IAZ015-023>028-035>039. WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ004>007-016-017. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
235 AM CST SUN FEB 10 2013 ...UPDATED LONG TERM SECTION... .SYNOPSIS... ISSUED AT 1126 PM CST SAT FEB 9 2013 AT 00Z SUNDAY A -31C 500MB LOW WAS LOCATED OVER WESTERN COLORADO, AND A +110KT 300MB JET STREAK EXTENDED FROM SOUTHWEST NEW MEXICO INTO THE PANHANDLE OF OKLAHOMA. A SURFACE AND 850MB LOW WAS LOCATED ACROSS EAST CENTRAL COLORADO AND WEST CENTRAL KANSAS. A DRYLINE EXTENDED SOUTH OF THIS LOW ACROSS EXTREME WESTERN KANSAS. A COLD FRONT STRETCHED FROM SOUTHWEST NEBRASKA, ACROSS NORTHWEST KANSAS, INTO EAST CENTRAL COLORADO. LOW LEVEL MOISTURE WAS PRESENT AHEAD OF THIS DRYLINE ACROSS WESTERN KANSAS WITH DODGE CITY 00Z SOUNDING INDICATING A SATURATED LAYER UP TO AROUND THE 800MB LEVEL. WIDESPREAD STATUS AND FOG WAS ALSO REPORTED EARLIER THIS MORNING. HAVILAND PROFILER AND 850MB WINDS AT 00Z INDICATED 40 TO 50KTS WERE PRESENT IN THE 850MB TO 800MB LEVEL. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 123 AM CST SUN FEB 10 2013 AN AREA OF LOW PRESSURE AT THE SURFACE LOCATED NEAR THE KANSAS/COLORADO BORDER EARLIER THIS MORNING WILL LIFT NORTHEAST ACROSS SOUTHERN NEBRASKA EARLY TODAY AS AN UPPER LEVEL TROUGH/LOW CROSSES THE CENTRAL PLAINS. A TIGHT SURFACE PRESSURE GRADIENT WILL EXIST ACROSS WESTERN AND NORTH CENTRAL KANSAS WITH 850MB WIND SPEEDS OF AROUND 50KTS FORECAST TO BE LOCATED IN NORTH CENTRAL KANSAS AT AROUND 18Z. THE TIGHT SURFACE PRESSURE GRADIENT ALONG WITH 40-50KT WINDS JUST ABOVE THE SURFACE CONTINUES TO SUPPORT WIND SPEEDS IN THE 30 TO 35 MPH RANGE ACROSS NORTH CENTRAL AND MOST OF WESTERN KANSAS TODAY. THE POSSIBLE EXCEPTION WILL BE IN EXTREME SOUTHWEST KANSAS NEAR ELKHART, BUT EVEN HERE WIND SPEEDS NEAR 30 MPH ARE STILL POSSIBLE. SOME LOW TO MID LEVEL MOISTURE LOCATED BEHIND A COLD FRONT WILL CROSS WESTERN KANSAS EARLY THIS MORNING, AND GIVEN 850MB TO 500MB LAPSE RATES IN EXCESS OF 8C/KM UNDER THE COLD UPPER LOW THERE MAY ALSO BE A FEW SPRINKLES OR A BRIEF SHOWER WILL POSSIBLE AROUND DAYBREAK ALONG THE INTERSTATE 70 CORRIDOR. TEMPERATURES TODAY WILL BE A LITTLE TRICKY ACROSS WEST CENTRAL AND NORTH CENTRAL KANSAS GIVEN THE CLOUD COVER EXPECTED. STILL UNSURE JUST HOW LONG THE CLOUDS WILL LINGER. GIVEN THIS ALONG WITH THE NAM AND GFS MODEL SOUNDINGS HAVE DECIDED TO STAY CLOSE TO THE COOLER MET GUIDANCE. FURTHER SOUTH, CLOSER TO THE OKLAHOMA BORDER, THE 00Z SUNDAY 850MB MIX DOWN TEMPERATURES FROM THE ECMWF AND GFS SUGGESTED HIGHS ONLY AROUND 50 DEGREES. HOWEVER GIVEN THE AMOUNT OF SUNSHINE EXPECTED AND THE MIXING DEPTH EXPECTED WITH THE NORTHWEST WINDS WILL STAY CLOSE TO THE WARMER PREVIOUS FORECAST. TONIGHT UNDER PARTLY TO MOSTLY CLEAR SKIES THE GUSTY NORTHWEST WINDS WILL SUBSIDE TO AROUND 10 MPH. LOWS FALLING BACK INTO THE 20S STILL APPEARS REASONABLE WITH SOME TEENS POSSIBLE IN NORTH CENTRAL AND WEST CENTRAL KANSAS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 235 AM CST SUN FEB 10 2013 A MID TO UPPER LEVEL SHORTWAVE IS EXPECTED TO MOVE DOWN ACROSS THE ROCKIES MONDAY THEN INTO THE CENTRAL AND SOUTHERN PLAINS MONDAY NIGHT INTO TUESDAY. CLOUDS INCREASE IN COVERAGE AS THIS SYSTEM APPROACHES WITH MOSTLY CLOUDY SKIES ANTICIPATED BY MONDAY NIGHT. A CHANCE OF SNOW WILL BE POSSIBLE ACROSS FAR SOUTHWEST KANSAS AND THE KS/OK BORDER MONDAY NIGHT INTO EARLY TUESDAY MORNING WITH A SLIGHT CHANCE FARTHER NORTH. ACCUMULATIONS ARE EXPECTED TO BE LIGHT WITH THE EXCEPTION OF AREAS ALONG THE KS/OK BORDER WHERE AN INCH OR TWO MAY BE POSSIBLE. CLOUDS DECREASE IN COVERAGE ON TUESDAY MORNING WITH MOSTLY CLEAR SKIES EXPECTED BY TUESDAY AFTERNOON. WINDS SHIFT TO MORE OF A NORTHERLY DIRECTION MONDAY THEN BECOME LIGHT AND VARIABLE MONDAY NIGHT INTO TUESDAY. A COLD DAY IS ANTICIPATED MONDAY WITH HIGHS RANGING FROM THE UPPER 30S ACROSS THE KS/CO BORDER TO MID 40S ACROSS SOUTH CENTRAL KANSAS. THE COLDEST TEMPERATURES OF THE FORECAST PERIOD ARE EXPECTED EARLY TUESDAY MORNING WITH LOWS RANGING FROM THE MID TEENS ACROSS THE KS/CO BORDER TO MID 20S ACROSS SOUTH CENTRAL KANSAS. HIGHS THEN REBOUND INTO THE 40S ON TUESDAY. TRANQUIL WEATHER IS ANTICIPATED TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. MOSTLY CLEAR SKIES AND DRY CONDITIONS ARE FORECASTED DURING THIS PERIOD WITH LIGHT NORTHWEST WINDS. LOWS WEDNESDAY MORNING WILL GENERALLY BE IN THE 20S WITH HIGHS WEDNESDAY IN THE LOWER 50S. LOWS THURSDAY MORNING ARE FORECASTED TO FALL INTO THE UPPER 20S AND LOWER 30S. MODELS THEN CONTINUE TO SUGGEST A MID TO UPPER LEVEL SHORTWAVE TO MOVE DOWN FROM CANADA AND INTO THE PLAINS THURSDAY INTO FRIDAY. IF THIS VERIFIES THIS WILL HELP PUSH A STRONG ARCTIC HIGH AND COLD FRONT DOWN THROUGH THE ROCKIES AND PLAINS. AS OF NOW, TIMING OF THIS FRONT LOOKS TO BE DURING THURSDAY AFTERNOON. INCREASED CLOUD COVER IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS THIS SYSTEM MOVES THROUGH WESTERN KANSAS. THE 00Z GFS AND ECMWF HINT AT THE CHANCE OF FLURRIES OR LIGHT SNOW THURSDAY NIGHT INTO FRIDAY AND HAVE PLACED A SLIGHT CHANCE IN THE GRIDS TO REFLECT THIS. HIGHS THURSDAY ARE FORECASTED TO RANGE FROM THE LOWER 40S ACROSS WEST CENTRAL KANSAS TO AROUND 50 DEGREES ACROSS SOUTH CENTRAL KANSAS. LOWS THURSDAY NIGHT WILL ONCE AGAIN DIP INTO THE 20S. COLD TEMPERATURES ARE FORECASTED BEHIND THIS SYSTEM FRIDAY WITH HIGHS RANGING FROM THE MID 30S ACROSS WEST CENTRAL KANSAS TO LOWER 40S ACROSS THE KS/OK BORDER. UPPER LEVEL RIDGING BUILDS ACROSS THE PLAINS THIS WEEKEND WITH HIGH PRESSURE BEING THE DOMINATING FEATURE AT THE SURFACE. THIS WILL BRING PARTLY CLOUDY SKIES AND DRY CONDITIONS TO WESTERN KANSAS. LOWS SATURDAY MORNING ARE FORECASTED TO BE IN THE LOWER 20S WITH HIGHS SATURDAY AFTERNOON REBOUNDING INTO THE 40S. LOWS SUNDAY MORNING LOOK TO DIP INTO THE MID TO UPPER 20S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1126 PM CST SAT FEB 9 2013 AREAS OF FOG AND IFR/LIFR CIGS WILL QUICKLY GIVE WAY TO VFR CONDITIONS AS A DRYLINE MOVES EAST ACROSS WESTERN KANSAS EARLY THIS MORNING. NAM AND HRRR BOTH SUGGEST VFR CONDITIONS AT GCK AT 06Z, AT DDC AROUND 07Z, AND A BRIEF PERIOD VFR CONDITIONS AT HYS BETWEEN 8Z AND 11Z. LOW LEVEL MOISTURE POOLING BEHIND A COLD FRONT SURGING SOUTHEAST ACROSS WESTERN KANSAS BEHIND THIS DRYLINE IS EXPECTED TO PRODUCE SOME MVFR CIGS AT HYS AND GCK BETWEEN 11Z AND 15Z WITH LOW VFR CIGS THEN BEING POSSIBLE AT HYS UNTIL 21Z. A TIGHT PRESSURE GRADIENT WILL PERSIST ACROSS WESTERN KANSAS BEHIND THE COLD FRONT. SUSTAINED NORTHWEST WINDS AT ALL THREE TAF SITES ARE EXPECTED TO RANGE FROM 25 TO 30KTS. THE STRONGER WIND SPEEDS ARE EXPECTED TO BE BETWEEN 17Z AND 22Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 21 42 22 / 0 0 10 30 GCK 43 19 39 19 / 0 0 10 20 EHA 49 20 38 20 / 0 10 10 30 LBL 48 21 41 21 / 0 10 10 30 HYS 42 21 41 19 / 10 0 10 10 P28 52 25 45 27 / 0 0 10 30 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING TO 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>066-074>081- 084>090. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...SUGDEN AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
126 AM CST SUN FEB 10 2013 ...UPDATED SHORT TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1126 PM CST SAT FEB 9 2013 AT 00Z SUNDAY A -31C 500MB LOW WAS LOCATED OVER WESTERN COLORADO, AND A +110KT 300MB JET STREAK EXTENDED FROM SOUTHWEST NEW MEXICO INTO THE PANHANDLE OF OKLAHOMA. A SURFACE AND 850MB LOW WAS LOCATED ACROSS EAST CENTRAL COLORADO AND WEST CENTRAL KANSAS. A DRYLINE EXTENDED SOUTH OF THIS LOW ACROSS EXTREME WESTERN KANSAS. A COLD FRONT STRETCHED FROM SOUTHWEST NEBRASKA, ACROSS NORTHWEST KANSAS, INTO EAST CENTRAL COLORADO. LOW LEVEL MOISTURE WAS PRESENT AHEAD OF THIS DRYLINE ACROSS WESTERN KANSAS WITH DODGE CITY 00Z SOUNDING INDICATING A SATURATED LAYER UP TO AROUND THE 800MB LEVEL. WIDESPREAD STATUS AND FOG WAS ALSO REPORTED EARLIER THIS MORNING. HAVILAND PROFILER AND 850MB WINDS AT 00Z INDICATED 40 TO 50KTS WERE PRESENT IN THE 850MB TO 800MB LEVEL. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 123 AM CST SUN FEB 10 2013 AN AREA OF LOW PRESSURE AT THE SURFACE LOCATED NEAR THE KANSAS/COLORADO BORDER EARLIER THIS MORNING WILL LIFT NORTHEAST ACROSS SOUTHERN NEBRASKA EARLY TODAY AS AN UPPER LEVEL TROUGH/LOW CROSSES THE CENTRAL PLAINS. A TIGHT SURFACE PRESSURE GRADIENT WILL EXIST ACROSS WESTERN AND NORTH CENTRAL KANSAS WITH 850MB WIND SPEEDS OF AROUND 50KTS FORECAST TO BE LOCATED IN NORTH CENTRAL KANSAS AT AROUND 18Z. THE TIGHT SURFACE PRESSURE GRADIENT ALONG WITH 40-50KT WINDS JUST ABOVE THE SURFACE CONTINUES TO SUPPORT WIND SPEEDS IN THE 30 TO 35 MPH RANGE ACROSS NORTH CENTRAL AND MOST OF WESTERN KANSAS TODAY. THE POSSIBLE EXCEPTION WILL BE IN EXTREME SOUTHWEST KANSAS NEAR ELKHART, BUT EVEN HERE WIND SPEEDS NEAR 30 MPH ARE STILL POSSIBLE. SOME LOW TO MID LEVEL MOISTURE LOCATED BEHIND A COLD FRONT WILL CROSS WESTERN KANSAS EARLY THIS MORNING, AND GIVEN 850MB TO 500MB LAPSE RATES IN EXCESS OF 8C/KM UNDER THE COLD UPPER LOW THERE MAY ALSO BE A FEW SPRINKLES OR A BRIEF SHOWER WILL POSSIBLE AROUND DAYBREAK ALONG THE INTERSTATE 70 CORRIDOR. TEMPERATURES TODAY WILL BE A LITTLE TRICKY ACROSS WEST CENTRAL AND NORTH CENTRAL KANSAS GIVEN THE CLOUD COVER EXPECTED. STILL UNSURE JUST HOW LONG THE CLOUDS WILL LINGER. GIVEN THIS ALONG WITH THE NAM AND GFS MODEL SOUNDINGS HAVE DECIDED TO STAY CLOSE TO THE COOLER MET GUIDANCE. FURTHER SOUTH, CLOSER TO THE OKLAHOMA BORDER, THE 00Z SUNDAY 850MB MIX DOWN TEMPERATURES FROM THE ECMWF AND GFS SUGGESTED HIGHS ONLY AROUND 50 DEGREES. HOWEVER GIVEN THE AMOUNT OF SUNSHINE EXPECTED AND THE MIXING DEPTH EXPECTED WITH THE NORTHWEST WINDS WILL STAY CLOSE TO THE WARMER PREVIOUS FORECAST. TONIGHT UNDER PARTLY TO MOSTLY CLEAR SKIES THE GUSTY NORTHWEST WINDS WILL SUBSIDE TO AROUND 10 MPH. LOWS FALLING BACK INTO THE 20S STILL APPEARS REASONABLE WITH SOME TEENS POSSIBLE IN NORTH CENTRAL AND WEST CENTRAL KANSAS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 337 PM CST SAT FEB 9 2013 ANOTHER UPPER LEVEL TROUGH WILL DIG INTO THE SOUTHERN ROCKIES BY MONDAY AFTERNOON AS COOL HIGH PRESSURE SETTLES INTO THE NORTHERN AND CENTRAL PLAINS. SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP ACROSS WEST TEXAS BY 00Z TUESDAY IN RESPONSE TO THE DIGGING SYSTEM. THE VARIOUS MODELS HANDLE THE SYSTEM DIFFERENTLY BY MONDAY NIGHT AND TUESDAY, BUT THE GFS/GEM AND ECMWF ARE IN REASONABLE AGREEMENT IN PLACING THE 500MB LOW CENTER AROUND WICHITA FALLS, TX BY 00Z WEDNESDAY. THE GEM IS MORE CLOSED OFF THAN THE ECMWF AND THEREFORE HAS HIGHER SNOW AMOUNTS ACROSS FAR SOUTHWEST KANSAS. THE SYSTEM WILL BE WEAKENING BY TUESDAY EVENING AND OPENING UP SO THAT THE BEST CHANCE FOR SNOW ACCUMULATIONS (PERHAPS 1 TO 2 INCHES) SHOULD BE FURTHER WEST INCLUDING ELKHART, LIBERAL AND ULYSSES, WITH LESSER AMOUNTS TO THE EAST AT MEDICINE LODGE. IT APPEARS THAT THE SNOW WILL OCCUR LATE MONDAY NIGHT AND TUESDAY MORNING, WITH SOME CLEARING BY TUESDAY AFTERNOON. SOME WARMING CAN BE EXPECTED BY WEDNESDAY AHEAD OF THE NEXT SHORTWAVE TROUGH. HIGHS SHOULD REACH INTO THE UPPER 40S TO LOWER 50S. THIS SYSTEM IS ADVERTISED TO DIG INTO THE SOUTHERN ROCKIES PER ECMWF, BUT THE OTHER MODELS ARE FURTHER EAST WITH THE TROUGH. NONE OF THE MODELS ARE FAVORABLE FOR PRECIPITATION. A COLD SURGE WILL PROGRESS DOWN THE PLAINS AHEAD OF THE SYSTEM THURSDAY NIGHT, BUT NOT BEFORE TEMPERATURES REACH INTO THE UPPER 40S TO LOWER 50S ON THURSDAY. COOLER HIGHS IN THE MID OR UPPER 30S CAN BE EXPECTED BY FRIDAY. SINCE SURFACE HIGH PRESSURE WILL BE FIRMLY IN PLACE AHEAD OF THE SYSTEM, LITTLE IN THE WAY OF LOW LEVEL THERMAL ADVECTIONS ARE EXPECTED SO THAT SNOW IS UNLIKELY THIS FAR NORTH AND EAST. TRANQUIL WEATHER CAN BE EXPECTED FOR FRIDAY AND INTO NEXT WEEKEND AS A NORTHWESTERLY FLOW PATTERN DEVELOPS ACROSS THE WESTERN UNITED STATES. LOW LEVEL MOISTURE FROM THE GULF WILL LIKELY STAY WELL TO THE SOUTHEAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1126 PM CST SAT FEB 9 2013 AREAS OF FOG AND IFR/LIFR CIGS WILL QUICKLY GIVE WAY TO VFR CONDITIONS AS A DRYLINE MOVES EAST ACROSS WESTERN KANSAS EARLY THIS MORNING. NAM AND HRRR BOTH SUGGEST VFR CONDITIONS AT GCK AT 06Z, AT DDC AROUND 07Z, AND A BRIEF PERIOD VFR CONDITIONS AT HYS BETWEEN 8Z AND 11Z. LOW LEVEL MOISTURE POOLING BEHIND A COLD FRONT SURGING SOUTHEAST ACROSS WESTERN KANSAS BEHIND THIS DRYLINE IS EXPECTED TO PRODUCE SOME MVFR CIGS AT HYS AND GCK BETWEEN 11Z AND 15Z WITH LOW VFR CIGS THEN BEING POSSIBLE AT HYS UNTIL 21Z. A TIGHT PRESSURE GRADIENT WILL PERSIST ACROSS WESTERN KANSAS BEHIND THE COLD FRONT. SUSTAINED NORTHWEST WINDS AT ALL THREE TAF SITES ARE EXPECTED TO RANGE FROM 25 TO 30KTS. THE STRONGER WIND SPEEDS ARE EXPECTED TO BE BETWEEN 17Z AND 22Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 21 42 22 / 0 0 0 30 GCK 45 19 39 19 / 0 0 0 30 EHA 46 20 38 20 / 0 10 10 40 LBL 48 21 41 21 / 0 10 10 40 HYS 44 21 41 19 / 0 0 0 10 P28 52 25 45 27 / 0 0 0 20 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING TO 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>066-074>081- 084>090. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...FINCH AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1133 PM CST SAT FEB 9 2013 ...UPDATED SYNOPSIS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1126 PM CST SAT FEB 9 2013 AT 00Z SUNDAY A -31C 500MB LOW WAS LOCATED OVER WESTERN COLORADO, AND A +110KT 300MB JET STREAK EXTENDED FROM SOUTHWEST NEW MEXICO INTO THE PANHANDLE OF OKLAHOMA. A SURFACE AND 850MB LOW WAS LOCATED ACROSS EAST CENTRAL COLORADO AND WEST CENTRAL KANSAS. A DRYLINE EXTENDED SOUTH OF THIS LOW ACROSS EXTREME WESTERN KANSAS. A COLD FRONT STRETCHED FROM SOUTHWEST NEBRASKA, ACROSS NORTHWEST KANSAS, INTO EAST CENTRAL COLORADO. LOW LEVEL MOISTURE WAS PRESENT AHEAD OF THIS DRYLINE ACROSS WESTERN KANSAS WITH DODGE CITY 00Z SOUNDING INDICATING A SATURATED LAYER UP TO AROUND THE 800MB LEVEL. WIDESPREAD STATUS AND FOG WAS ALSO REPORTED EARLIER THIS MORNING. HAVILAND PROFILER AND 850MB WINDS AT 00Z INDICATED 40 TO 50KTS WERE PRESENT IN THE 850MB TO 800MB LEVEL. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 220 PM CST SAT FEB 9 2013 A STRONG UPPER LOW AND SHORTWAVE TROUGH WILL MOVE FROM SOUTHEAST COLORADO AND NEW MEXICO AND LIFT NORTHEASTWARD AND DEEPEN AS IT MOVES INTO CENTRAL NEBRASKA AND KANSAS OVERNIGHT. A SURFACE DRYLINE TROUGH WILL ADVANCE RAPIDLY EASTWARD FROM EASTERN COLORADO AND ACROSS WESTERN KANSAS WITH A FEW THUNDERSTORMS POSSIBLE ALONG AND AHEAD OF THE DRYLINE, AS THE MID LEVEL COLD POOL ADVANCES INTO WESTERN KANSAS. NEW MODELS SHOW LIMITED CAPE OF 200 TO 500 J/KG AND WITH SETTING OF THE SUN AND COOLING THE CAPE FIELDS QUICKLY DECREASE. NOT EXPECTING ANY SEVERE WEATHER TONIGHT, HOWEVER SOME SMALL HAIL IS POSSIBLE AND SHOULD BE LESS THAN DIME SIZE. WILL KEEP 20 TO 40 PERCENT CHANCES FOR THUNDERSTORMS WITH THE HIGHER CHANCES FROM WAKEENEY TO DODGE CITY AND EAST. STRONG SOUTH WINDS OF 25 TO 35 MPH MAY CONTINUE THROUGH 9 OR 10 PM TONIGHT AND MAY HAVE TO EXTEND THE WIND ADVISORY PAST THE CURRENT ONE THAT ENDS AT 7 PM CST. OVERNIGHT LOWS WILL BE FAIRLY MILD WITH GOOD MIXING TONIGHT AND FROM THE LOWER 30S FAR WEST TO THE MID AND UPPER 30S EAST ACROSS SOUTH CENTRAL KANSAS. FOR SUNDAY WILL NEED ANOTHER WIND ADVISORY WITH WEST TO NORTHWEST WINDS OF 30 TO NEAR 40 MPH WITH HIGHER GUSTS. WILL HAVE STRONG MOMENTUM MIX DOWN POTENTIAL BEHIND THE EXITING UPPER LEVEL SHORTWAVE TROUGH WITH MOSTLY SUNNY TO PARTLY CLOUDY SKIES. HIGHS IN THE MID TO UPPER 40S LOOK REASONABLE WITH WARMER LOWER 50S IN THE COLDWATER TO MEDICINE LODGE AREAS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 337 PM CST SAT FEB 9 2013 ANOTHER UPPER LEVEL TROUGH WILL DIG INTO THE SOUTHERN ROCKIES BY MONDAY AFTERNOON AS COOL HIGH PRESSURE SETTLES INTO THE NORTHERN AND CENTRAL PLAINS. SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP ACROSS WEST TEXAS BY 00Z TUESDAY IN RESPONSE TO THE DIGGING SYSTEM. THE VARIOUS MODELS HANDLE THE SYSTEM DIFFERENTLY BY MONDAY NIGHT AND TUESDAY, BUT THE GFS/GEM AND ECMWF ARE IN REASONABLE AGREEMENT IN PLACING THE 500MB LOW CENTER AROUND WICHITA FALLS, TX BY 00Z WEDNESDAY. THE GEM IS MORE CLOSED OFF THAN THE ECMWF AND THEREFORE HAS HIGHER SNOW AMOUNTS ACROSS FAR SOUTHWEST KANSAS. THE SYSTEM WILL BE WEAKENING BY TUESDAY EVENING AND OPENING UP SO THAT THE BEST CHANCE FOR SNOW ACCUMULATIONS (PERHAPS 1 TO 2 INCHES) SHOULD BE FURTHER WEST INCLUDING ELKHART, LIBERAL AND ULYSSES, WITH LESSER AMOUNTS TO THE EAST AT MEDICINE LODGE. IT APPEARS THAT THE SNOW WILL OCCUR LATE MONDAY NIGHT AND TUESDAY MORNING, WITH SOME CLEARING BY TUESDAY AFTERNOON. SOME WARMING CAN BE EXPECTED BY WEDNESDAY AHEAD OF THE NEXT SHORTWAVE TROUGH. HIGHS SHOULD REACH INTO THE UPPER 40S TO LOWER 50S. THIS SYSTEM IS ADVERTISED TO DIG INTO THE SOUTHERN ROCKIES PER ECMWF, BUT THE OTHER MODELS ARE FURTHER EAST WITH THE TROUGH. NONE OF THE MODELS ARE FAVORABLE FOR PRECIPITATION. A COLD SURGE WILL PROGRESS DOWN THE PLAINS AHEAD OF THE SYSTEM THURSDAY NIGHT, BUT NOT BEFORE TEMPERATURES REACH INTO THE UPPER 40S TO LOWER 50S ON THURSDAY. COOLER HIGHS IN THE MID OR UPPER 30S CAN BE EXPECTED BY FRIDAY. SINCE SURFACE HIGH PRESSURE WILL BE FIRMLY IN PLACE AHEAD OF THE SYSTEM, LITTLE IN THE WAY OF LOW LEVEL THERMAL ADVECTIONS ARE EXPECTED SO THAT SNOW IS UNLIKELY THIS FAR NORTH AND EAST. TRANQUIL WEATHER CAN BE EXPECTED FOR FRIDAY AND INTO NEXT WEEKEND AS A NORTHWESTERLY FLOW PATTERN DEVELOPS ACROSS THE WESTERN UNITED STATES. LOW LEVEL MOISTURE FROM THE GULF WILL LIKELY STAY WELL TO THE SOUTHEAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1126 PM CST SAT FEB 9 2013 AREAS OF FOG AND IFR/LIFR CIGS WILL QUICKLY GIVE WAY TO VFR CONDITIONS AS A DRYLINE MOVES EAST ACROSS WESTERN KANSAS EARLY THIS MORNING. NAM AND HRRR BOTH SUGGEST VFR CONDITIONS AT GCK AT 06Z, AT DDC AROUND 07Z, AND A BRIEF PERIOD VFR CONDITIONS AT HYS BETWEEN 8Z AND 11Z. LOW LEVEL MOISTURE POOLING BEHIND A COLD FRONT SURGING SOUTHEAST ACROSS WESTERN KANSAS BEHIND THIS DRYLINE IS EXPECTED TO PRODUCE SOME MVFR CIGS AT HYS AND GCK BETWEEN 11Z AND 15Z WITH LOW VFR CIGS THEN BEING POSSIBLE AT HYS UNTIL 21Z. A TIGHT PRESSURE GRADIENT WILL PERSIST ACROSS WESTERN KANSAS BEHIND THE COLD FRONT. SUSTAINED NORTHWEST WINDS AT ALL THREE TAF SITES ARE EXPECTED TO RANGE FROM 25 TO 30KTS. THE STRONGER WIND SPEEDS ARE EXPECTED TO BE BETWEEN 17Z AND 22Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 34 47 21 42 / 20 0 0 0 GCK 31 45 19 39 / 20 0 0 0 EHA 30 47 19 38 / 30 0 10 10 LBL 31 49 20 41 / 20 0 10 10 HYS 34 45 22 41 / 20 0 0 0 P28 37 53 25 45 / 50 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 9 AM CST /8 AM MST/ TO 6 PM CST /5 PM MST/ SUNDAY FOR KSZ030-031-043>046-061>066-074>081-084>090. && $$ SYNOPSIS...BURGERT SHORT TERM...KRUSE LONG TERM...FINCH AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS PADUCAH KY
305 AM CST SUN FEB 10 2013 .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 305 AM CST SUN FEB 10 2013 LATEST SFC ANALYSIS SHOWS A SFC LOW OVER NW KANSAS AND A COLD FRONT EXTENDING SOUTHWARD INTO OK AND TX. THIS LOW WILL SCOOT NORTHEAST OVERNIGHT AND BE SITUATED OVER SOUTH CENTRAL NEBRASKA AT 12Z. PRIOR TO 12Z...IT APPEARS WE WILL CONTINUE TO SEE A BAND OF SCATTERED SHOWERS MOVE ACROSS THE REGION. BUT THE MAIN ACTION SHOULD BE AFTER 12Z...AS THE LOW TRAVELS FURTHER NORTHEAST TOWARD OMAHA NEBRASKA. WE SHOULD SEE A NEARLY SOLID BAND OF RAIN WITH EMBEDDED STORMS ROLL THROUGH HERE FROM WEST TO EAST THROUGHOUT THE DAY. IT APPEARS THE TIMING OF THE RAIN/STORMS MAY HAVE TO BE SPED UP EVEN MORE. AT 0800Z...THE MAIN LINE OF CONVECTION WAS ALREADY LINED UP FROM SE KS THROUGH CENTRAL OK AND INTO CENTRAL TX. THIS IS SEVERAL HOURS AHEAD OF WHERE THE LATEST RUC ANALYSIS INDICATES IT SHOULD BE. AT THIS RATE...THE LINE COULD BE ENTERING THE OZARKS AT 12Z. HAVE ADJUSTED HOURLY POPS ACCORDINGLY AND ADJUSTMENTS WILL BE MADE THROUGHOUT THE MORNING AS THINGS PROGRESS. BY 00Z MONDAY...THE BEST CHANCES WILL LINGER IN OUR EASTERN SECTIONS...AND BE EXITING THE ENTIRE AREA DURING THE EARLY EVENING HOURS AS THE ACTUAL COLD FRONT PUSHES EAST OF THE CWA. STILL NOT SEEING GREAT MOISTURE RETURN FORECAST OVER THE AREA...WITH MODELS ONLY SHOWING DEWPOINTS IN THE LOWER TO MAYBE MID 50S (SOUTH). LOOKING AT LATEST OBS...WE HAVE A WHILE BEFORE WE SEE THOSE 50S DEWS. BETTER SFC BASED INSTABILTY IS DEFINITELY TO OUR SOUTH...BUT MODELS ARE ABLE TO COME UP WITH A FEW HUNDRED JOULES/KG OF MU CAPE DURING THE DAY. WIND FIELDS ARE DEFINITELY A CONCERN...AS THEY STRENGTHEN THROUGHOUT THE DAY. BUT WITH LIMITED INSTABILITY AND WEAK LAPSE RATES...OTHER THAN AN ISOLATED STG TO SVR STORM...THE CHANCES FOR WIDESPREAD SEVERE WEATHER APPEAR VERY LOW. HOWEVER...COULD STILL SEE SOME LOCALLY HEAVY RAIN...AS PW/S STILL INDICATE A GOOD DEAL OF MOISTURE FOR THIS TIME OF YEAR. THE GRADIENT SHOULD TIGHTEN UP AS WELL...AS WE COULD SEE SOME GUSTY WINDS DEVELOP OVER THE NEXT SEVERAL HRS. MODEL SOUNDINGS AND LAYER WIND PLOTS INDICATE 25 TO 30 KTS RIGHT OFF THE DECK...IF WE CAN MIX THAT DOWN. THE WINDS WILL LIKELY STAY UP THROUGHOUT THE NIGHT AND INTO MONDAY...AS THE MAIN SFC LOW TAKES ITS TIME MOVING ACROSS THE GREAT LAKES REGION. THE STRONGEST WINDS WILL BE ACROSS OUR NORTHERN COUNTIES ON MONDAY...BUT THEN START TO SLACKEN OFF BY THE END OF THE DAY AND INTO THE NIGHT...AS HIGH PRESSURE BUILDS IN. AS FAR AS TEMPS...WE WILL SEE A SPIKE IN LOW LEVEL TEMPS AHEAD OF THE COLD FRONT TODAY...AND WE SHOULD SEE THE MERCURY RESPOND TO THIS WITH HIGHS IN THE MID TO UPPER 50S. COULD EVEN SEE 60 DEG AT PLACES LIKE POPLAR BLUFF MO...PADUCAH KY...AND HOPKINSVILLE KY MAYBE. A PRETTY GOOD PUSH OF COLD AIR FILTERS IN BEHIND THE FRONT LATE TONIGHT AND INTO MONDAY WHICH WILL KICK TEMPS BACK DOWN TO NEAR NORMAL OR SLIGHTLY ABOVE NORMAL...WITH THE COLDEST READINGS IN THE NORTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 305 AM CST SUN FEB 10 2013 THERE ARE TWO MAIN ISSUES TO DEAL WITH IN THE EXTENDED PORTION OF THE FORECAST. THE FIRST IS THE REMNANT FOUR CORNERS LOW/TROUGH THAT IS EXPECTED TO MOVE EASTWARD OVER OUR REGION TUESDAY NIGHT. THE SECOND IS WHAT TO DO WITH A SIGNIFICANT TROUGH THAT THE MODELS DEVELOP OVER THE EASTERN THIRD OF THE COUNTRY LATE THIS WEEK AND INTO NEXT WEEKEND. THE GFS CONTINUES TO BE THE WETTEST FOR TUESDAY NIGHT...AND IT IS SUPPORTED BY THE NAM. THESE MODELS ARE GENERATING A QUARTER INCH OF LIQUID QPF. THE CANADIAN MODEL IS SLIGHTLY DRIER...WHILE THE ECMWF IS QUITE DRY...BASICALLY ONLY SPITTING OUT A FEW HUNDREDTHS. ALL OF THE MODELS HAVE RATHER COMPACT AND SHARP TROUGHS MOVING THROUGH THE REGION...WITH THE BASE WELL SOUTH OF THE AREA. IT WOULD NOT BE A STRETCH TO SEE A SMALL CLOSED LOW WITH THIS SYSTEM. THIS WOULD PUT THE QUAD STATE REGION IN THE DEFORMATION ZONE...WITH THE POTENTIAL FOR BANDING. THE BANDS WOULD LIKELY BE ORIENTED EAST TO WEST...WHICH IS PARALLEL TO THE SYSTEM MOTION. THIS COULD RESULT IN SOME AREAS GETTING A NICE SNOWFALL...A FEW INCHES...WHILE OTHER AREAS CLOSE BY GET LITTLE OR NO SNOW ACCUMULATION. TEMPERATURE PROFILES CONTINUE TO INDICATE SATURATION DEEP ENOUGH FOR SNOW TO FORM ALOFT...AND THE ONLY WARM LAYER BASED RIGHT AT THE SURFACE. WITH THE FORCING INDICATED IN THE GFS/GEM/NAM...THE LOW-LEVELS SHOULD COOL MORE THAN INDICATED IN THE MODELS. TEMPERATURES MAY ONLY DROP TO AROUND THE FREEZING MARK...BUT THAT WOULD BE SUFFICIENT TO ALLOW SNOW TO ACCUMULATE...IF IT FALLS HARD ENOUGH. WE HAVE BEEN BITTEN BY THIS SORT OF THE THING IN THE PAST. THE PRECIPITATION WILL LIKELY START AS RAIN AND MIX WITH AND EVENTUALLY CHANGE OVER TO ALL SNOW. DID NOT WANT TO JUMP TOO FAR FROM THE PREVIOUS FORECAST AT THIS TIME...SO JUST MENTIONED RAIN AND SNOW TUESDAY NIGHT AND EARLY WEDNESDAY WITH NO ACCUMULATIONS. HOWEVER...DID INCREASE POPS UP TO AROUND 40 IN THE SOUTH...AND WILL MENTION THE POSSIBILITY OF ACCUMULATING SNOW IN THE HWO. SOUTHWEST WINDS AND SEASONABLY MILD CONDITIONS ARE EXPECTED WEDNESDAY AND THURSDAY...BEFORE THE MAJOR PATTERN SHIFT OCCURS. AS IS THE CASE WITH MOST SIGNIFICANT PATTERN SHIFTS...THE MODELS ALL EVENTUALLY GET THERE...BUT THEY ARE NOT LOCKED IN ON THE DETAILS OR TIMING. THE ECMWF HAS DIVERGED FROM THE GFS AND GEM COMPARED TO YESTERDAYS RUNS. WHAT WE KNOW WITH SOME CONFIDENCE IS THAT THERE WILL BE LITTLE OR NO LOW-LEVEL MOISTURE RETURN AHEAD OF THE INDIVIDUAL SHORT WAVE TROUGHS THAT WILL CARVE OUT THE LARGER TROUGH. THE MODELS HAVE A DIFFICULT TIME DEVELOPING ANY TANGIBLE PRECIPITATION...SO ESPECIALLY GIVEN THE LACK OF MODEL AGREEMENT ON TIMING INDIVIDUAL DISTURBANCES...HAVE ELECTED TO KEEP THE FORECAST DRY THURSDAY NIGHT THROUGH SUNDAY. THE CONSENSUS OF 00Z MODEL GUIDANCE BRINGS A SIGNIFICANT SHOT OF COLD AIR INTO THE REGION FRIDAY INTO SATURDAY. IF THERE WERE TO BE PRECIPITATION BEHIND THIS COLD FRONT...IT WOULD MOST LIKELY BE LIGHT SNOW NEXT WEEKEND. THIS FORECAST HAS TEMPERATURES DROPPING BELOW NORMAL FRIDAY AND THEN ONLY REACHING THE 30S FOR HIGHS ON SATURDAY. SUNDAY WILL SEE SOME MODERATION...BUT TEMPERATURES WILL STRUGGLE TO GET TO THE 40S. && .AVIATION... ISSUED AT 1035 PM CST SAT FEB 9 2013 LIGHT SHOWERS AND SPRINKLES CAME IN FASTER THAN FORECAST. WILL CONTINUE WITH A VCSH / -RA MENTION THROUGH THE OVERNIGHT THEN TRANSITION OVER TO HEAVIER SHOWERS AND THE POSSIBILITY OF TSRA FOR SUNDAY. CONTINUED WITH MVFR TO MARGINAL IFR CONDITIONS WITH THE CONVECTIVE ACTIVITY. WINDS SHOULD PICK UP AND BE GUSTY FROM THE SSE. GUSTS IN THE 20-30KT RANGE EXPECTED. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...CW LONG TERM...DRS
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
658 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA THIS EVENING. HIGH PRESSURE BRIEFLY BUILDS IN TUESDAY BEFORE DEVELOPING LOW PRESSURE APPROACHES THE REGION FROM THE MID-SOUTH STATES ON WEDNESDAY. HIGH PRESSURE THEN MOVES IN FOR THE LATE WEEK BEFORE THE WEATHER PATTERN BECOMES ACTIVE AGAIN OVER THE WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... THE WEDGE HAS FINALLY BROKEN IN ALL AREAS EXCEPT OUR FAR NE...WHERE IT MAY NOT UNTIL THE COLD FRONT MOVES ACROSS THIS EVENING. STILL QUITE WARM JUST BEFORE 7 PM...WITH TEMPS IN THE 50S AND 60S...BUT COOLER AIR IS ON THE DOORSTEP. THE COLDER AIR IS EXPECTED TO ENTER THE WRN MOST ZONES NEAR THE ALLEGHENY FRONT EARLY THIS EVENING...AND SPREAD ACROSS THE REST OF THE AREA BY/SHORTLY AFTER MIDNIGHT. WESTERLY WINDS BEHIND THE FROPA WILL BRING IN SIGNIFICANTLY DRIER AND SOMEWHAT COOLER AIR...AND A STRONG LOW LEVEL JET OF WESTERLIES WILL DEVELOP AS WELL. THE HIGHER ELEVATION RIDGES WILL BE MOST LIKELY TO SEE STRONGER WINDS AS THE COLD AIR RUSHES IN. A WIND ADVISORY REMAINS IN EFFECT THROUGH 10 AM TUESDAY FOR THE HIGHER RIDGES OF THE CWA. RAPPAHANNOCK COUNTY WAS ADDED TO THE ADVISORY AREA AS HRRR OUTPUT SHOWS ESPECIALLY RIDGES IN THE SRN PART OF THE COUNTY SEEING HIGHER WINDS. SEEING SOME OBSERVED GUSTS ALREADY IN THE I-81 CORRIDOR /SOME NOT IN HIGHER ELEVATIONS OR IN THE ADVISORY AREA/ OF 30-35 KNOTS...SO WILL BE MONITORING FOR NEED TO EXPAND ADVISORY NORTHWARD. EVEN IF ADVISORY CRITERIA IS NOT MET...IT WILL DEFINITELY BE BREEZY...HOLDING MIN TEMPS UP BUT LOWERING WIND CHILLS. RAISED MIN TEMPS OVERNIGHT AND LOWERED APPARENT TEMPS WITH 7 PM UPDATE...AND WILL REVISIT BEFORE 10 PM AS NEW GUIDANCE ARRIVES. ON TUE...THE PRESSURE GRADIENT AND GUSTY WINDS WILL SUBSIDE DURING THE AFTN AS HIPRES SETTLES OVRHD IN THE AFTN. PLENTY OF SUNSHINE AND W-NW DOWNSLOPING FLOW WILL ALSO MODERATE AIRMASS. FCST MAX TEMP RANGE FROM THE MID 40S IN THE POTOMAC HIGHLANDS AND NRN MD TO MID AND UPPER 50S IN CENTRAL VA. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... A POSITIVELY TILTED SOUTHERN JET STREAM UPPER TROUGH OVER TEXAS TUESDAY EVENING WILL EJECT EAST TO THE MID-SOUTH THEN CAROLINAS THROUGH WEDNESDAY. A COASTAL SURFACE LOW IS EXPECTED TO DEVELOP NEAR THE NC/VA BORDER AND INTENSIFY AS IT MOVES NORTHEAST ALONG THE DELMARVA COAST WEDNESDAY EVENING. WINTER WEATHER IS LIKELY NORTHWEST OF THIS LOW ACROSS THE CENTRAL MID ATLANTIC WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. TUESDAY NIGHT...UPR LOW EJECTS EAST FROM TEXAS WITH OVERRUNNING HIGH CLOUDS OVERSPREADING AND THICKENING ACROSS THE CWA THROUGH THE NIGHT. CONTINUED SOME LOW CHANCE POPS FOR ZONES SW OF KCHO LATE IN THE NIGHT WHERE A LIGHT WINTRY MIX MAY START BEFORE SUNRISE. TIMING OF CLOUDS KEY FOR MIN TEMPS WHICH ARE ANTICIPATED TO BE AROUND 30F FROM THE MASON-DIXON TO THE NRN SHEN VLY...LOW TO MID 30S BALT-WASH METRO AND SOUTH TO KCHO. WEDNESDAY INTO WEDNESDAY NIGHT...CONFIDENCE HAS INCREASED ON SEEING PRECIP ACROSS THE LWX CWA FROM A DEVELOPING SFC LOW TRACKING JUST SOUTH OF THE CWA BOUNDARY. UPR TROUGH BECOMES MORE NEUTRALLY TILTED AS IT TRACKS ACROSS THE SOUTHERN MID ATLANTIC. 12Z ECMWF IS IN BETTER ALIGNMENT WITH GEFS MEMBERS /WHICH THEMSELVES HAVE MUCH CLOSER CLUSTERING OF SFC LOW AT 00Z THURSDAY. DYNAMIC COOLING DEPENDS ON THE RATE OF SFC LOW DEVELOPMENT WHICH LOOKS STEADY BUT NOT OVERLY AGGRESSIVE AS OF THIS TIME /LESS THAN ONE MB PER HOUR/. SNOW MAY BE LIMITED TO THE HIGHER ELEVATIONS AND IN STRONGER BANDS. HOWEVER THESE BANDS MAY PERSIST OVER SIMILAR AREAS...PRODUCING ACCUMULATING SNOWFALL. WILL UPDATE THE HWOLWX FOR THIS WORDING. STILL THINK IT WILL BE A RAIN CHANGING OVER TO SNOW FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING. UNDERCUT MAV/MET GUIDANCE BY A COUPLE DEGREES FOR MAX TEMPS...WENT MORE LOW TO MID 40S. AREAS EAST OF I-95 DO NOT LOOK TO DROP BELOW 32F /FOR FREEZEUP CONCERNS/. IN FACT ONLY AREAS WEST OF THE BLUE RIDGE LOOK TO DIP AS LOW AS 30F. && .LONG TERM /THURSDAY THROUGH MONDAY/... HIGH PRESSURE BRIEFLY THURSDAY. THEN ACTIVE PATTERN RESUMES THROUGH THE WEEKEND WITH A DEEP ERN CONUS TROUGH BRINGING ARCTIC AIR TO THE GULF COAST BY FRIDAY. MAINTAINED CHANCE POPS AND CONTINUED SNOW/MIX WORDING FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT. WILL ADD MENTION OF POTENTIAL SNOW IN THE HWO. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... ONLY MTN REMAINS SOCKED IN FROM THE WEDGE OF COLDER/SATURATED AIR NEAR THE SFC. THIS MAY REMAIN THE CASE UNTIL THE COLD FRONT MOVES THROUGH. OTHERWISE...EVERYONE ELSE IS NOW VFR AND SHOULD STAY THAT WAY TONIGHT. WLY WINDS WILL BECOME BREEZY IN WAKE OF FROPA TNGT AND TUE WITH GUSTS 20-25 KT EXPECTED AT TIMES. VFR TUESDAY NIGHT BEFORE THE NEXT PRECIP OVERSPREADING WEDNESDAY INTO WEDNESDAY NIGHT. HIGH PRESSURE THURSDAY. && .MARINE... GUSTY S-SW WINDS BETWEEN 15-25 KT CONTINUE OVER THE LOWER TIDAL POTOMAC RVR AND CENTRAL CHSPK BAY. WINDS WILL CONTINUE TO INCREASE FARTHER NORTH AS THE STABLE WEDGE OF COLDER AIR MIXES OUT. THE SCA REMAINS IN EFFECT FOR ALL MARINE ZONES THRU THE NGT SINCE WINDS PICK UP BEHIND A COLD FRONT THAT PASSES THRU THIS EVE. SCA CONTINUES ON TUE AS W-NW WINDS GUST 20-25 KT. LOW DEVELOPING IN WEDNESDAY TIMEFRAME AROUND THE CHESAPEAKE BAY REGION WOULD LEAD TO MORE MARINE WIND HEADLINES. HIGH PRESSURE ON THURSDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WIND ADVISORY UNTIL 10 AM EST TUESDAY FOR MDZ501-502. VA...WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST TUESDAY FOR VAZ025>027-029-036>040-503-504. WV...WIND ADVISORY UNTIL 10 AM EST TUESDAY FOR WVZ050-055-501>506. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ530>543. && $$ SYNOPSIS...BAJ/JE NEAR TERM...JE/JRK SHORT TERM...BAJ LONG TERM...BAJ AVIATION...JE/BAJ/JRK MARINE...BAJ/JRK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
329 PM EST SUN FEB 10 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH THE REGION TONIGHT BEFORE MOVING EAST OF THE CHESAPEAKE BAY ON MONDAY AFTERNOON. HIGH PRESSURE BUILDS IN BRIEFLY MONDAY PRIOR TO DEVELOPING LOW PRESSURE APPROACHING THE REGION WEDNESDAY FROM THE SOUTHEASTERN UNITED STATES. HIGH PRESSURE THEN MOVES IN BEFORE THE PATTERN BECOMES ACTIVE AGAIN LATE IN THE WEEK. && .NEAR TERM /THROUGH MONDAY/... THE SFC HIGH HAS SHIFTED S AND E OF THE AREA THIS AFTN WHILE LOPRES ADVANCES NEWD ACROSS THE CENTRAL PLAINS. WAA FROM LGT SLY RETURN FLOW AROUND THE HIGH COMBINED WITH FILTERED SUNSHINE HAS ALLOWED FOR A NICE REBOUND IN TEMPS THIS AFTN WITH HIGHS IN THE 40S. THE LOW WILL TRACK NEWD ACROSS THE UPPER MIDWEST TNGT. WHILE THE BEST UPPER DYNAMICS ASSOCIATED WITH THIS VERTICALLY-STACKED CYCLONE WILL REMAIN WELL TO THE NORTH AND WEST OF THE AREA...A STRONG /50-60 KT/ SLY LLVL JET WILL DEVELOP OVER THE ERN SEABOARD TNGT IN ADVANCE OF THE COLD FRONT. 12Z MODELS REMAIN IN GOOD AGREEMENT WITH TIMING OF PRECIP...WHICH FOLLOWS CLOSELY THE PASSAGE OF THE H5 RIDGE AXIS AND ARRIVAL OF SIGNIFICANT ISENTROPIC LIFT/MOISTURE ADVECTION. FCST REFLECTS A SLIGHTLY FASTER ONSET SINCE OVERRUNNING PRECIP TENDS TO COMES IN EARLIER THAN MODELS INDICATE. THE BIGGEST CHALLENGE WITH THE FCST TNGT IS EVALUATING THE THREAT FOR FREEZING RAIN. MOST GUIDANCE TDA HAS BEEN TOO AGGRESSIVE WITH MOISTURE RETURN. FOR EXAMPLE THE 12Z NAM...GFS AND LAST FEW RUNS OF THE RAP HAVE BEEN VERIFYING DEWPOINTS 5-10F TOO HIGH. A SLY BREEZE AND CLOUDS SHOULD LIMIT AMT OF RADIATIONAL COOLING PRIOR TO PRECIP THIS EVE. MIN TEMPS LIKELY TO OCCUR SHORTLY ONCE RAIN STARTS AS EVAPORATIVE COOLING WILL CAUSE TEMPS TO DROP DOWN TO THE WET BULB. THERE IS STILL AN OUTSIDE CHANCE TEMPS WET BULB DOWN TO FREEZING IN SHELTERED VLYS NEAR THE MASON-DIXON LINE AND NRN POTOMAC HIGHLANDS. EVEN IF THIS DOES HAPPEN...RAIN FALLING THRU A 4-6C WARM NOSE DOES NOT SUPPORT ICE ACCRETION AT THE SFC. MODELS CONTINUE TO SHOW SIGNIFICANT INTRUSION OF WARM AIR INTO THE BOUNDARY LAYER...WHICH WOULD LEAD TO RISING TEMPS OVNGT. THERE IS A CONCERN THAT IN-SITU CAD WILL BE STRONG ENOUGH TO INHIBIT THESE WINDS FROM REACHING THE BOUNDARY LAYER AND THUS TEMPS DO NOT RISE AS SHARPLY. PRECIP WILL END DURING THE MRNG AS THE LLVL JET SHIFTS EAST OF THE AREA. THE COLD FRONT WILL MOVE THRU DURING THE LATE MRNG AND AFTN. WENT WITH A MORE PESSIMISTIC FCST FOR LOCATIONS EAST OF THE BLUE RIDGE AND IN NRN MD IN TERMS OF HOW LONG WE HANG ON TO LOW CLOUDS AND FOG PRIOR TO FROPA. LOWERED MAX TEMPS IN THESE LOCATIONS AS WELL. MON FEATURES A LARGE SPREAD IN MAX TEMPS...RANGING FROM THE UPPER 40S NEAR THE MASON-DIXON LINE TO MID 60S IN THE CENTRAL FOOTHILLS AND CENTRAL SHENANDOAH VLY. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... SPRAWLING OCCLUDED LOW WILL MOVE EAST ACROSS SOUTHEASTERN CANADA MONDAY NIGHT THROUGH TUESDAY AS A ZONAL FLOW DEVELOPS OVER THE ERN CONUS WITH AN UPPER LOW OVER THE DESERT SOUTHWEST. MONDAY NIGHT...STRONG WLY FLOW JUST OFF THE DECK TO THE SOUTH OF THE VERTICALLY STACKED LOW OVER OTTAWA /DUE NORTH FROM DC/. DOWNSLOPING FLOW WILL CLEAR SKIES WELL EAST OF THE ALLEGHENY FRONT. WLY FLOW IS NOT IDEAL FOR UPSLOPE SNOW...THEREFORE MAINTAINED LOW CHANCES FOR SNOW SHOWERS WEST OF THE ALLEGHENY FRONT. DECENT CONFIDENCE ON MAV/MET BLEND FOR MIN TEMPS OF MID 20S IN THE HIGHLANDS...LOW TO MID 30S EAST TO THE VA/MD PIEDMONT...UPR 30S BALT-WASH METRO AND SRN MD. TUESDAY...WLY FLOW LIGHTER BUT ENOUGH TO MIX DOWN 20 TO 25 MPH GUSTS. DOWNSLOPING FLOW AND SCATTERED OR LESS CLOUDS SHOULD RESULT IN MILD TEMPS. MEX BLEND WITH PREVIOUS GIVES MID TO UPR 40S NRN 3RD OF THE CWA...MID TO UPR 50S KCHO AND SOUTH /AROUND 50F FOR DC/. TUESDAY NIGHT...UPR LOW EJECTS EAST FROM DESERT SW WITH OVERRUNNING HIGH CLOUDS OVERSPREAD AND THICKENING ACROSS THE CWA THROUGH THE NIGHT. CONTINUE SOME LOW CHANCE POPS FOR THE FAR SWRN ZONES FOR LATE IN THE NIGHT WHERE A LIGHT WINTRY MIX MAY START BEFORE SUNRISE. TIMING OF CLOUDS KEY FOR MIN TEMPS WHICH WILL LOOK TO BE AROUND FREEZING FOR ALL OF THE CWA EXCEPT FOR THE SRN TIER. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... WEDNESDAY INTO WEDNESDAY NIGHT...UPR TROUGH TRACKS ACROSS MID-SOUTH STATES TO THE CAROLINAS. STILL A DIFFERENCE BETWEEN 12Z GFS/ECMWF WITH GFS FARTHER NORTH/POSSIBLE SNOW EVENT AND ECMWF STAYING SOUTH WITH LITTLE PRECIP FOR THE CWA. WITH GEFS MEMBERS STILL DISPLAYING QUITE A RANGE OF LOCATIONS FOR SFC LOWS...DELAYED POPS AND DECREASED FOR NRN HALF OF THE CWA AS A COMPROMISE. WILL HAVE TO KEEP WATCHING THIS ONE WITH SFC CYCLOGENESIS EXPECTED SOMEWHERE NEAR THE LWX CWA. TEMPERATURES ARE MARGINAL FOR SNOW...BUT DYNAMIC COOLING FROM DEVELOPMENT WOULD ALLOW FOR SNOW ACROSS HIGHER ELEVATIONS AND IN STRONGER BANDS. WENT MORE RAINY WEDNESDAY TO A SNOW/SLEET MIX WEDNESDAY NIGHT. LOW CONFIDENCE AS OF NOW. ACTIVE PATTERN CONTINUES FOR LONG TERM WITH DEEP ERN CONUS TROUGH BY FRIDAY. MAINTAINED CHANCE POPS AND CONTINUED SNOW/MIX WORDING THROUGH END OF FORECAST PERIOD. WILL ALSO HAVE TO WATCH THIS PERIOD FOR SIGNIFICANT WINTER WEATHER. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS THRU THIS EVE. RA WILL OVERSPREAD THE TERMINALS FROM WEST TO EAST LATE THIS EVE AND OVNGT. UNTIL A COLD FRONT PASSES THRU...EXPECT MVFR/IFR CIGS AND VSBYS TO DEVELOP BETWEEN 06Z-09Z AND CONTINUE THRU THE MRNG EVEN AFTER THE RAIN ENDS. WINDS AT 2K FT AGL INCREASE TO 40 KT OVNGT. LLWS WAS INCLUDED IN THE 18Z TAFS MAINLY FOR THE 06Z-14Z PERIOD. LLWS FROM WLY FLOW EXPECTED MONDAY NIGHT...WLY FLOW GUSTS UP TO 25 KT ON TUESDAY. NEXT PRECIP POSSIBLE MIDWEEK. && .MARINE... LGT SLY WINDS 5-10 KT WILL GRADUALLY INCREASE THIS AFTN AND EVE. SLY WINDS CONTINUING TO INCREASE EXPECT TO REACH SCA THRESHOLD IN THE MAIN STEM OF THE CHSPK BAY AND LWR TIDAL POTOMAC RVR BY THE ERY MRNG. THE SCA EXPANDS TO INCLUDE ALL WATERS DURING THE DAY ON MON WITH WIDESPREAD 20-25 KT EXPECTED. EXTENDED SCA ACROSS THE WATERS FOR MONDAY NIGHT. SOME GUSTS AROUND 20 KT POSSIBLE...WITH STRONGER WINDS JUST OFF THE SFC. LOW DEVELOPING IN WEDNESDAY TIMEFRAME AROUND THE CHESAPEAKE BAY REGION WOULD LEAD TO MORE MARINE WIND HEADLINES. && .TIDES/COASTAL FLOODING... SLY FLOW WILL CONTINUE TO STRENGTHEN TNGT AND MON. POSITIVE TIDAL ANOMALIES HAVE INCREASED TDA AND ARE CURRENTLY AROUND THREE-QUARTERS FT. WILL NEED POSITIVE TIDAL ANOMALIES TO DOUBLE IN ORDER TO CAUSE MINOR COASTAL FLOODING AT THE MOST SENSITIVE LOCATIONS SUCH AS ANNAPOLIS AND ALEXANDRIA. CURRENT CBOFS KEEPS LVLS BELOW ADVISORY THRESHOLD AT ALL LOCATIONS THRU THE NEXT FEW HIGH TIDE CYCLES TNGT AND AND MON. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 3 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ531>534-537-539>541-543. SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ530-535-536-538-542. && $$ SYNOPSIS...BAJ NEAR TERM...JRK SHORT TERM...BAJ LONG TERM...BAJ AVIATION...BAJ/JRK MARINE...BAJ/JRK TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
437 AM EST SUN FEB 10 2013 .SYNOPSIS... HIGH PRESSURE WILL SHIFT EAST TODAY WITH ONE MORE DRY DAY IN STORE FOR THE REGION. A COLD FRONT WILL THEN BRING RAIN TO THE UPPER OHIO VALLEY AS IT APPROACHES FROM THE WEST TONIGHT AND CROSSES THE AREA ON MONDAY. BEHIND THE FRONT...SNOW SHOWERS WILL BE POSSIBLE ACROSS PORTIONS OF THE AREA MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD 500MB RIDGE CENTERED ACROSS THE OHIO VALLEY WITH OUR AREA IN A WEST- NORTHWESTERLY FLOW JUST AHEAD OF THE AXIS OF THIS FEATURE. AT THE SURFACE...AN ELONGATED AREA OF HIGH PRESSURE EXTENDS FROM NEW YORK INTO THE EASTERN CAROLINAS. DESPITE A DEEP LAYER OF DRY AIR THE SURFACE THAT HAS BROUGHT CLEAR SKIES OVERNIGHT...STRATOCUMULUS IS BEGINNING TO SPILL IN FROM THE SOUTHWEST AHEAD OF THE NEXT FRONTAL SYSTEM. TODAY...THE MID-LEVEL RIDGE WILL CROSS THE UPPER OHIO VALLEY AS A SURFACE LOW MOVES INTO THE UPPER MID-WEST AND SWINGS A COLD FRONT ACROSS THE MISSOURI VALLEY. 700-250MB MOISTURE WILL ADVECT INTO THE AREA WELL AHEAD OF THE FRONT...INCREASING SKY COVERAGE TO MOSTLY CLOUDY TODAY. A SOUTHWESTERLY LOW-LEVEL FLOW WILL BECOME MORE SOUTHERLY BY THIS EVENING...ENHANCING WAA WITH 850MB TEMPS INCREASING TO 5-7C ACROSS THE AREA BY 00Z MONDAY. TEMPS ARE A FEW DEGREES WARMER THAN MAV/MET GUIDANCE...WITH HIGHS RANGING FROM THE MID 40S NORTH OF I-80 AND ACROSS THE HIGHER ELEVATIONS OF THE LAUREL HIGHLANDS TO THE MID 50S ACROSS NORTH-CENTRAL WV AND PORTIONS OF EASTERN OHIO. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... NAM/GFS/SREF 700MB OMEGA FIELDS INDICATE SUFFICIENT FORCING FOR WIDESPREAD PRE-FRONTAL SHOWERS TO BEGIN TO PUSH INTO EASTERN OHIO AFTER 00Z TONIGHT...REACHING THE PITTSBURGH METRO BY AROUND 06Z. NUMEROUS SHOWERS WILL CONTINUE WITH WAA AHEAD OF THE FRONT UNTIL AROUND 15Z WHEN THE COLD FRONT REACHES THE AREA. THUS...CATEGORICAL POPS ARE FORECAST IN THIS TIME FRAME. WITH TEMPS WARMING INTO THE 40S AND 50S ACROSS THE AREA TODAY AND WAA OVERNIGHT...ONLY CHANCE OF SUB-FREEZING TEMPS WITH THE ONSET OF RAIN LOOKS TO BE WHERE COLD AIR MAY HOLD IN FOREST/JEFFERSON COUNTIES AND THE VALLEYS OF GARRETT/TUCKER COUNTIES. THUS...A FEW HOURS OF FREEZING RAIN ARE FORECAST DURING THE PRE-DAWN HOURS MONDAY THERE. THIS REMAINS MENTIONED IN THE HWO. TEMPS WILL ONLY DROP SLIGHTLY SUNDAY NIGHT...WITH LOWS ARE NAM/GFS BLEND...RANGING FROM THE LOWER 30S IN THE LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE LOWER 40S IN EASTERN OHIO AND NORTHERN WV. BEFORE THE FRONT PUSHES THROUGH...HIGHS EARLY ON MONDAY WILL RANGE FROM THE MID 40S NORTH OF PITTSBURGH TO THE MID 50S IN NORTH-CENTRAL WV. BEHIND THE FRONT...CAA WILL BE WEAK AS THE LOW-LEVEL FLOW SHIFTS TO SOUTHWESTERLY IN THE 18Z-00Z MONDAY TIME FRAME. THUS...THE CHANCE OF RAIN SHOWERS WILL LOWER WITH DECREASING THICKNESSES FINALLY ALLOWING FOR A CHANGE OVER TO SNOW AFTER 00Z TUESDAY. BEST CHANCE FOR SNOW SHOWERS MONDAY NIGHT WILL BE ALONG THE LAUREL HIGHLANDS/ALLEGHENY FRONT OF WV/MD/PA WHERE SOME UPSLOPING ENHANCEMENT WILL OCCUR. STILL...LITTLE OR NO ACCUMULATION IS EXPECTED AS GROUND TEMPS WILL BE RELATIVELY WARM AND PRECIPITATION LIGHT. LOWS ARE A MAV/MET BLEND ON MONDAY NIGHT...AROUND 5 DEGREES ABOVE SEASONAL NORMALS. TUESDAY AND TUESDAY NIGHT...GFS/NAM INDICATE A CLOSED UPPER LOW WILL PASS NORTH OF THE AREA EARLY ON TUESDAY AND LEAVE THE AREA IN A CYCLONIC...WEST-NORTHWESTERLY FLOW WITH SOME WEAK VORT ENERGY SWINGING ACROSS AREAS NORTH OF PITTSBURGH. ALTHOUGH THE VORT WILL PROVIDE FORCING...AVAILABLE MOISTURE WILL BE LIMITED IN A WEST-NORTHWESTERLY FLOW OVER A MOSTLY FROZEN LAKE ERIE. THUS WENT WITH CHC POPS NORTH OF I-80 ON TUESDAY. HIGH PRESSURE BUILDING IN FROM THE WEST WILL THEN ALLOW FOR A DRY FORECAST ACROSS THE AREA ON TUESDAY NIGHT. TEMPS WILL BE NEAR NORMAL SEASONAL VALUES TUESDAY AND TUES NIGHT. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE MODELS ARE IN FAIRLY GOOD AGREEMENT AT THE START OF THE PERIOD AS AN UPPER LEVEL POSITIVELY TILTED TROUGH SWINGS TOWARDS THE OHIO VALLEY. AT THE SURFACE...BOTH THE ECMWF AND GFS TRANSLATE THIS TO THE DEVELOPMENT ACROSS THE MID ATLANTIC COASTLINE. WHAT DIFFERS IS THIS LOW PLACEMENT...WITH THE GFS BRINGING THE LOW AND PRECIP CLOSE ENOUGH TO CLIP THE SOUTHEASTERN HALF OF THE REGION...AND THE ECMWF KEEPING THE SYSTEM JUST A BIT FURTHER SOUTH. WITH BETTER RUN TO RUN CONSISTENCY WITH THE GFS AND THE NEWEST ECMWF AND GEFS SUGGESTING A SLIGHTLY NORTHWARD TRACK...HEDGED MORE TOWARDS THE 12Z GFS AND MEX GUIDANCE THROUGH THIS PERIOD. THE MODELS THEN HAVE LARGER DIFFERENCES IN REGARDS TO THE SYSTEM PROGGED FOR FRI/SAT. WITH THE CONTINUITY BETWEEN RUNS DEGRADING WITH THIS SECOND SYSTEM...OPTED TO TAKE A SOLUTION CLOSER TO HPC BUT REMAINED CLOSE TO MEX GUIDANCE FOR THE REMAINDER OF THE PERIOD. IN GENERAL KEPT TEMPERATURES NEAR NORMAL THROUGH THE PERIOD. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... HIGH CLOUDS WILL SLOWLY START TO MOVE INTO THE AREA FROM THE SOUTHWEST OVERNIGHT TOWARD MORNING. THESE WILL SLOWLY THICKEN THROUGH THE DAY AS THE GRADIENT FORCES MORE SOUTHEASTERLY FLOW OVER THE AREA. DEEPER MOISTURE APPROACHES AFTER 11/02Z ON THE NOSE OF A STRONG SSW LOW LEVEL JET OF AROUND 50-55 KTS. THIS WILL BRING LOW LEVEL WIND SHEAR OVER ALL SITES STARTING BETWEEN 11/02Z AND 11/05Z ROUGHLY COINCIDENT WITH THE START OF PRECIPITATION. FRIES .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS WILL RETURN IN RAIN SUNDAY NIGHT AND MONDAY...AND CONTINUE IN SNOW SHOWERS MONDAY NIGHT AND TUESDAY. ANOTHER SYSTEM COULD CLIP LBE AND MGW WEDNESDAY/THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
109 AM EST SUN FEB 10 2013 .SYNOPSIS... HIGH PRESSURE WILL SHIFT EAST TODAY WITH ONE MORE DRY DAY IN STORE FOR THE REGION. A COLD FRONT WILL THEN BRING RAIN TO THE UPPER OHIO VALLEY AS IT APPROACHES FROM THE WEST TONIGHT AND CROSSES THE AREA ON MONDAY. BEHIND THE FRONT...SNOW SHOWERS WILL BE POSSIBLE ACROSS PORTIONS OF THE AREA MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /THROUGH TODAY/... AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH LITTLE CHANGE TO THE FORECAST EARLY THIS MORNING. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD 500MB RIDGE CENTERED ACROSS THE OHIO VALLEY WITH OUR AREA IN A WEST-NORTHWESTERLY FLOW JUST AHEAD OF THE AXIS OF THIS FEATURE. AT THE SURFACE...AN ELONGATED AREA OF HIGH PRESSURE EXTENDS FROM NEW YORK INTO THE EASTERN CAROLINAS. WITH DEEP SUBSIDENCE AND A DRY LAYER ALOFT...SKIES ARE MOSTLY CLEAR ACROSS THE AREA. THE EXCEPTION IS CIRRUS BEGINNING TO SPILL IN FROM THE SOUTHWEST AHEAD OF THE NEXT FRONTAL SYSTEM. TODAY...THE MID-LEVEL RIDGE WILL CROSS THE UPPER OHIO VALLEY AS A SURFACE LOW MOVES INTO THE UPPER MID-WEST AND SWINGS A COLD FRONT ACROSS THE MISSOURI VALLEY. 700-250MB MOISTURE WILL ADVECT INTO THE AREA WELL AHEAD OF THE FRONT...INCREASING SKY COVERAGE TO MOSTLY CLOUDY BY EVENING. A SOUTHWESTERLY LOW-LEVEL FLOW WILL BECOME MORE SOUTHERLY BY THIS EVENING...ENHANCING WAA WITH 850MB TEMPS INCREASING TO 5-7C ACROSS THE AREA BY 00Z MONDAY. TEMPS ARE A FEW DEGREES WARMER THAN MAV/MET GUIDANCE...WITH HIGHS RANGING FROM THE MID 40S NORTH OF I-80 AND ACROSS THE HIGHER ELEVATIONS OF THE LAUREL HIGHLANDS TO THE MID 50S ACROSS NORTH-CENTRAL WV AND PORTIONS OF EASTERN OHIO. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... MODELS IN GOOD OVERALL AGREEMENT ON OCCLUDED BOUNDARY QUICKLY MOVING ACROSS THE UPPER OHIO VALLEY SUNDAY NIGHT INTO EARLY MONDAY AS PARENT LOW PRESSURE SPINS ACROSS THE GREAT LAKES. RAIN WILL OVERSPREAD THE AREA SUNDAY NIGHT AND CONTINUE INTO EARLY MONDAY BEFORE TRANSITIONING TO SHOWERS AS BOUNDARY EXITS. MODEL SOUNDINGS CONTINUE TO SHOW A BRIEF PERIOD OF FREEZING RAIN POSSIBLE ACROSS THE RIDGES AND NORTHEAST AREAS ESPECIALLY AT THE ONSET OF OF THE RAIN. HAVE ONLY LEFT A CHANCE OF FREEZING RAIN IN FORECAST AS TEMPERATURES SUNDAY WILL BE QUITE WARM WITH A GOOD AMOUNT OF SUNSHINE. SURFACE WINDS WILL BE SOUTHEAST TO SOUTH AS THE NIGHT GOES ON AND WITH CONTINUED WARM ADVECTION ANY LOW LEVEL COLD AIR REMAINING SHOULD BE SCOURED OUT. TEMPERATURES SUNDAY NIGHT WILL FALL A BIT EARLY THEN HOLD STEADY OR RISE. A FAST SHOT OF RAIN WITH QPF ONE QUARTER TO ONE HALF INCH SHOULD NOT CAUSE ANY HYDRO PROBLEMS. BEHIND BOUNDARY MONDAY AFTERNOON COLD ADVECTION WILL RETURN BY LATE DAY WITH SOME MOISTURE WRAPPING UNDERNEATH GREAT LAKES LOW. THIS WILL KEEP A CHANCE OF SHOWERS MONDAY AFTERNOON CHANGING TO SNOW SHOWERS AND DIMINISHING INTO TUESDAY. TEMPERATURES WILL TRANSITION BACK TO NORMAL TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE MODELS ARE IN FAIRLY GOOD AGREEMENT AT THE START OF THE PERIOD AS AN UPPER LEVEL POSITIVELY TILTED TROUGH SWINGS TOWARDS THE OHIO VALLEY. AT THE SURFACE...BOTH THE ECMWF AND GFS TRANSLATE THIS TO THE DEVELOPMENT ACROSS THE MID ATLANTIC COASTLINE. WHAT DIFFERS IS THIS LOW PLACEMENT...WITH THE GFS BRINGING THE LOW AND PRECIP CLOSE ENOUGH TO CLIP THE SOUTHEASTERN HALF OF THE REGION...AND THE ECMWF KEEPING THE SYSTEM JUST A BIT FURTHER SOUTH. WITH BETTER RUN TO RUN CONSISTENCY WITH THE GFS AND THE NEWEST ECMWF AND GEFS SUGGESTING A SLIGHTLY NORTHWARD TRACK...HEDGED MORE TOWARDS THE 12Z GFS AND MEX GUIDANCE THROUGH THIS PERIOD. THE MODELS THEN HAVE LARGER DIFFERENCES IN REGARDS TO THE SYSTEM PROGGED FOR FRI/SAT. WITH THE CONTINUITY BETWEEN RUNS DEGRADING WITH THIS SECOND SYSTEM...OPTED TO TAKE A SOLUTION CLOSER TO HPC BUT REMAINED CLOSE TO MEX GUIDANCE FOR THE REMAINDER OF THE PERIOD. IN GENERAL KEPT TEMPERATURES NEAR NORMAL THROUGH THE PERIOD. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... HIGH CLOUDS WILL SLOWLY START TO MOVE INTO THE AREA FROM THE SOUTHWEST OVERNIGHT TOWARD MORNING. THESE WILL SLOWLY THICKEN THROUGH THE DAY AS THE GRADIENT FORCES MORE SOUTHEASTERLY FLOW OVER THE AREA. DEEPER MOISTURE APPROACHES AFTER 11/02Z ON THE NOSE OF A STRONG SSW LOW LEVEL JET OF AROUND 50-55 KTS. THIS WILL BRING LOW LEVEL WIND SHEAR OVER ALL SITES STARTING BETWEEN 11/02Z AND 11/05Z ROUGHLY COINCIDENT WITH THE START OF PRECIPITATION. FRIES .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS WILL RETURN IN RAIN SUNDAY NIGHT AND MONDAY...AND CONTINUE IN SNOW SHOWERS MONDAY NIGHT AND TUESDAY. ANOTHER SYSTEM COULD CLIP LBE AND MGW WEDNESDAY/THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
657 PM EST MON FEB 11 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 406 PM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...BROAD MID LEVEL TROUGH AND ASSOC CLOSED LOW ARE PROGRESSING STEADILY EAST OF THE UPPER GREAT LAKES. IN RESPONSE TO INCREASED RDGG FROM THE WEST...MODELS INDICATE INCREASING Q-VECT DIV/SUBSIDENCE SPREADING WEST TO EAST ACROSS FCST AREA INTO THIS EVENING. COMBINATION OF MQT RADAR...VIS SATELLITE AND AREA WEB CAMS SUGGEST ONLY LIGHT SNOW OR FLURRIES ACROSS THE CWA. THERE IS A BETTER BAND OF LES OVER WRN LAKE SUPERIOR AFFECTING NW WI THIS AFTERNOON WITH LIGHT TO MODERATE SNOW PER DLH RADAR. GIVEN THAT DEEPER MOISTURE WILL EXIT EAST TONIGHT WITH FLOW BCMG INCREASINGLY ANTICYCLONIC...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. AS A RESULT OF CONTINUED DIMINISHING TREND TO LES...EXPECT TO CANCEL REMAINING WINTER WX ADVISORIES OVER WRN COUNTIES ON THE AFTERNOON FCST ISSUANCE. EVEN IF BAND OVER NW WI DOES SWING INTO FAR WRN UPR MI...BELIEVE ANY INCREASE IN LES WILL BE SHORT-LIVED AND NOT BE WORTHY OF ADVISORY HEADLINE. LINGERING LIGHT LAKE EFFECT IS EXPECTED EAST TUE MORNING...BUT INCREASED DRYING/RDGG FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION SHOULD QUICKLY DIMINISH OR END LAKE EFFECT SNOW DURING THE DAY TUESDAY. EXPECT CLOUDS TO GENERALLY DIMINISH AS WELL THROUGH THE DAY WITH INCREASED RDGG. GENERALLY FOLLOWED A BLEND OF CONSENSUS MODEL GUIDANCE FOR LOW TEMPS TONIGHT AND HIGH TEMPS ON TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 406 PM EST MON FEB 11 2013 EXPECT NW FLOW ALOFT THROUGH MUCH OF THE LONG TERM PERIOD...WITH SEVERAL OPEN WAVES DIVING TOWARD THE UPPER GREAT LAKES. LAKE EFFECT SNOW SHOWERS OVER THE KEWEENAW PENINSULA...AND NEAR AND EAST OF MUNISING NEAR LAKE SUPERIOR WILL BE COMMON. THE NEXT SYSTEM TO INFLUENCE OUR WEATHER WILL BE IN THE FORM OF A SFC TROUGH EXTENDING FROM THE PARENT LOW OVER HUDSON BAY. THE TROUGH WILL SWEEP W-E ACROSS UPPER MI TUESDAY NIGHT...BEFORE EXITING TO EASTERN ONTARIO LATE WEDNESDAY MORNING. 850MB TEMPS OF -7 TO -10C. YET ANOTHER QUICK CLIPPER SYSTEM SET UP OVER CENTRAL ALBERTA AND SASKATCHEWAN TUESDAY NIGHT WILL QUICKLY CROSS LAKE WINNIPEG WEDNESDAY MORNING...AND PUSH INTO WESTERN LAKE SUPERIOR WEDNESDAY EVENING...THEN ACROSS CENTRAL UPPER MI/LAKE SUPERIOR BY 12Z THURSDAY...AND EASTERN UPPER MI AROUND 18Z. WHILE THE NAM/GFS/ECMWF/SREF SHOW A SIMILAR TRACK TO THE SFC LOW...THE 11/00Z CANADIAN IS APPROX 300MI SW OF THE CONSENSUS. WILL LIMIT THE USE OF THE 11/00Z CANADIAN FORECAST FOR WEDNESDAY THROUGH THURSDAY. SNOW AMOUNTS WEDNESDAY NIGHT THROUGH THURSDAY COULD ACCUMULATE 3 TO 6 INCHES OF LES FROM IWD UP THROUGH THE KEWEENAW PENINSULA...WITH SNOW TO LIQUID RATIOS AROUND 17:1. LIGHTER AMOUNTS OF 2 TO 5 INCHES WILL BE POSSIBLE NORTH CENTRAL...AND 1 TO 3 INCHES ELSEWHERE. WILL ADD THE MENTION OF LIGHT TO MODERATE SNOW WITH LAKE ENHANCEMENT FOR WEDNESDAY NIGHT THROUGH THURSDAY...BEFORE THE DGZ FALLS CLOSER TO THE SFC AS COLDER AIR PUSHES IN...LIMITING SIGNIFICANT ACCUMULATIONS. A WEAKENING SFC TROUGH WILL AGAIN LINGER ACROSS CENTRAL AND EASTERN LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY AS STRONGER HIGH PRESSURE SINKS ACROSS THE CENTRAL CANADA AND THE PLAINS STATES...WITH A RIDGE EDGING INTO WESTERN UPPER MI/LAKE SUPERIOR. THE 11/12Z GFS WAS A BIT STRONGER WITH WHAT THE ECMWF HAS AS AN OPEN WAVE PUSHING IN FROM THE NNW SATURDAY...ACCENTUATING THE SFC LOW OVER EASTERN LAKE SUPERIOR. EITHER WAY...LAKE EFFECT SNOW SHOWERS WILL BE LINGERING OVER CENTRAL AND EASTERN UPPER MI NEAR LAKE SUPERIOR. EXPECT LES TO PICK UP SIGNIFICANTLY THURSDAY AFTERNOON AND EVENING AS COLDER AIR FILTERS IN BEHIND THE EXITING LOW ON FAVORABLE NNW WINDS. 850MB TEMPS WILL FALL TO AROUND -17C OVER THE W HALF BY THE END OF THE DAY THURSDAY...WITH FURTHER COOLING TO -19 TO -20C THROUGH THE START OF THE WEEKEND. -22 TO -24C LOOKS TO BE THE COOLEST POINT...SATURDAY AFTERNOON. WHILE THE 11/06Z GFS AND 11/00Z ECMWF ARE PRETTY CONSISTENT UNTIL SATURDAY...THEY BEGIN TO DIVERGE SATURDAY AFTERNOON...WITH THE GFS DEVELOPING A LOW OVER THE CENTRAL PLAINS BECOMING OUT OF PHASE WITH THE REST OF THE AVAILABLE MODELS. THE GOOD NEWS IS THAT THE 11/12Z GFS LOOKS TO HAVE FIXED THIS POTENTIAL PROBLEM...AND ANOTHER POSSIBLE STORM TOWARD THE EAST COAST FOR THE UPCOMING WEEKEND. EXPECT A COOL RIDGE OF HIGH PRESSURE TO EDGE ACROSS THE UPPER GREAT LAKES FOR THE WEEKEND...AS AN ELONGATED TROUGH GAINS STEAM FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES ON SUNDAY. FOR MONDAY IT WILL BE A QUESTION AS TO IF THE SOUTHERN OR NORTHERN STREAM WINS OUT. AT THIS POINT THE 11/00Z ECMWF LOOKS TO BE STRONGER WITH THE SYSTEM AS A WHOLE...BUT WILL WAIT UNTIL THE TIME PERIOD BECOMES A BIT MORE CLEAR BEFORE LEANING TO ONE SOLUTION OVER ANOTHER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 656 PM EST MON FEB 11 2013 IFR CONDITIONS AT IWD/CMX ARE EXPECTED TO IMPROVE EARLY THIS EVENING AS ANY LAKE EFFECT SNOW DIMINISHES. SO...MAINLY MVFR CONDITIONS ARE EXPECTED THIS EVENING WITH CONTINUED MOIST NW FLOW AND MINOR LAKE EFFECT SNOW/FLURRIES IN NORTHERN UPPER MICHIGAN BEHIND THE DEPARTING LOW PRESSURE SYTEM. MVFR CIGS MAY SCATTER OUT LATE TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW UNDER DOWNSLOPING W TO NW WINDS. LOOK FOR MVFR CIGS TO SCT OUT AT BOTH KCMX AND KSAW BY LATE TUE MORNING WITH INCREASED SUBSIDENCE AND RDGG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 406 PM EST MON FEB 11 2013 NW GALES OVER CENTRAL LAKE SUPERIOR AIDED BY PRES RISE MAX WILL DIMINISH BLO GALES BY LATE EVENING AS NW GRADIENT WEAKENS DUE TO LOW DEPARTING EAST AND RDG BUILDING IN FM WEST. HIGH PRES RDG AXIS MOVG EAST ACROSS THE LAKE WILL KEEP WINDS AOB 20 KTS OVER EAST HALF OF LAKE SUPERIOR. WEST HALF AND FAR NCNTRL LAKE SHOULD SEE AN INCREASE IN SW WINDS TUE AFTERNOON TO 25 KTS WITH TIGHTENING GRAD ON BACKSIDE OF RDG AXIS. A WEAK TROUGH STRETCHING FROM HUDSON BAY THROUGH THE UPPER GREAT LAKES TUESDAY NIGHT WILL BE REINFORCED BY ANOTHER LOW FROM THE NORTHWEST...THAT WILL PUSH ACROSS LAKE SUPERIOR/UPPER MI THURSDAY MORNING INTO THURSDAY AFTERNOON...BEFORE QUICKLY EXITING INTO SOUTERN ONTARIO AND QUEBEC THURSDAY AFTERNOON/EVENING. A FEW N GALE FORCE GUSTS TO 35KTS WILL BE POSSIBLE THURSDAY AFTERNOON ACROSS MAINLY CENTRAL LAKE SUPERIOR...WITH HEAVY FREEZING SPRAY OVER MUCH OF THE LAKE THURSDAY NIGHT. WHILE A WEAKENING TROUGH OF LOW PRESSURE REMAINS OVER EASTERN LAKE SUPERIOR...HIGH PRESSURE WILL SLOWLY BUILD IN FROM THE WEST THORUGH SATURDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>250-265-266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...JLB MARINE...VOSS/KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1041 AM EST SUN FEB 10 2013 .UPDATE... ISSUED AT 1040 AM EST SUN FEB 10 2013 FEW CHANGES NEEDED THIS MORNING AS WE TRACK THE APPROACHING SFC LOW JUST WEST OF COLUMBUS KS /KOLU/ AT 15Z. THE CLOSEST BAND OF PRECIPITATION STRETCHES FROM NEAR ST. CLOUD MN /KSTC/ SOUTHEASTWARD THROUGH SOUTHERN WI /NEAR DECORAH WI KDEH/...MOVING NNE AROUND 45KTS. WHILE SNOW REMAINS THE PREDOMINANT WEATHER TYPE ACROSS THE WESTERN EDGE...THERE IS A TRANSITION TO MIXED PRECIP AND RAIN TOWARD EASTERN MN AND WESTERN WI...WHERE PRECIPITATION LOOKS MORE CONVECTIVE WITH POCKETS OF 45-50DBZ REFLECTIVITY. THERE WERE A FEW...MAINLY NEGATIVE...LIGHTNING STRIKES ACROSS SW MN AROUND 13Z. OTHERWISE...LIGHTNING HAS REMAINED WELL TO OUR S ACROSS IA AND IL. WHILE LIGHTNING IS NOT EXPECTED AS THE SYSTEM NEARS LATER THIS AFTERNOON...SOME OF THESE STRONGER REFLECTIVITIES WILL PRODUCE HEAVIER PRECIPITATION...WITH 1IN/HR SNOW AMOUNTS OR GREATER OVER FAR WESTERN UPPER MI. WILL CONTINUE TO MONITOR THE APPROACHING WINTRY MIX OF PRECIPITATION. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 543 AM EST SUN FEB 10 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING OUT OVER THE WRN PLAINS...AND 00Z RAOBS AND SFC OBS INDICATE THAT SYSTEM HAS DEVELOPED A GOOD GULF MOISTURE CONNECTION. THE MID LEVEL LOW WILL TRACK NE...REACHING THE UPPER LAKES MON MORNING. ALTHOUGH MODELS ARE IN GOOD AGREEMENT ON THE TRACK OF THE MID LEVEL LOW AND ASSOCIATED SFC LOW...FCST REMAINS A CHALLENGE WITH RESPECT TO PTYPES AS EVAPORATIVE AND THEN DYNAMIC COOLING BATTLE STRONG WAA. WITH THE STRONG WAA REGIME TAPPING A SOLID GULF MOISTURE FEED...PRECIPITABLE WATER SURGES TO 250-300PCT OF NORMAL IN THE UPPER LAKES...PROVIDING POTENTIAL FOR HVY PCPN. HOWEVER... HEAVIEST PCPN WILL BE SHORT-LIVED (ABOUT 4-6HRS) ON THE FRONT SIDE OF THE SYSTEM AS STRONG ISENTROPIC ASCENT RAPIDLY SHIFTS ACROSS THE AREA PER 295K SFC WHICH SHOWS 40-50KT WINDS PERPENDICULAR TO ISOBARS. ALTHOUGH THERE IS ABUNDANT AVBL MOISTURE...QUICK MOVEMENT OF THIS VIGOROUS ASCENT WILL HELP KEEP PCPN TOTALS IN CHECK. NARROW MIDLEVEL DRY SLOT PUNCHING N COULD LEAD TO SOME CONVECTIVE PCPN ON TAIL END OF THE ISENTROPIC ASCENT/MAIN PCPN BAND THIS EVENING (MODELS ALSO SHOW SHOWALTER INDEX FALLING CLOSE TO 0C). AS FOR PTYPE...IT REMAINS A TOUGH CALL. FCST SOUNDINGS FROM THE NAM/GFS SHOW TEMP PROFILE HOVERING NEAR 0C THRU A RATHER SUBSTANTIAL LOW-LEVEL DEPTH...AND THE NAM IN PARTICULAR SHOWS SURGES OF ABOVE 0C TEMPS AT TIMES...SUGGESTING EPISODES OF VARYING PTYPES. WITH HIGH RES TEMP PROFILE INFO NOT AVBL FOR THE UKMET/REGIONAL GEM/UKMET/ECMWF...USE OF 850MB TEMPS AND 1000-850MB THICKNESS DOES NOT CLARIFY OR ADD ANY CERTAINTY TO THE PTYPE FCST. OF THOSE MODELS...THE REGIONAL GEM IS QUITE WARM IN THE LOW-LEVELS AS IT HAS 1000-850MB THICKNESS RISING ABOVE 1300M TONIGHT ACROSS NEARLY THE ENTIRE FCST AREA AND AS HIGH AS 1320M ACROSS THE SCNTRL/SE FCST AREA. IF CORRECT...PCPN WOULD CHANGE TO MOSTLY RA/FZRA OVER MUCH OF THE AREA. AT THIS POINT...WILL INCLUDE MIXED PTYPES ROUGHLY SE OF A MARQUETTE TO CRYSTAL FALLS LINE. IT MAY BE ONE OF THOSE EVENTS WHERE PCPN IS MOSTLY SNOW DURING PERIOD OF STRONGEST FORCING/HEAVIEST PCPN AND THEN MORE OF A MIX OR A TRANSITION TO LIQUID PTYPES DURING PERIODS OF LIGHT PCPN. MIXING RATIOS SOLIDLY AROUND 4G/KG ON THE 295K SFC AND ABOUT 6 HRS OF STRONG ISENTROPIC ASCENT SUGGEST POTENTIAL FOR AROUND 4 INCHES OF SNOW WHERE PTYPE IS EXCLUSIVELY SNOW. THE SNOW WILL BE WET/HVY DUE TO A NARROW AND HIGH DGZ (SNOW-TO-WATER WILL PROBABLY BE DOWN AROUND 10 TO 1). STRONGER DEEP LAYER FORCING PER QVECTORS WILL PASS ACROSS THE NW FCST AREA...SO TOTALS THERE MAY BE HIGHER. IN FACT OVER THE NW...SNOW AMOUNTS WILL BE CLOSE TO THE WARNING CRITERIA OF 6 INCHES/12HR FOR LOW SNOW TO WATER RATIO SNOW. LATER SHIFTS WILL NEED TO MONITOR FOR POSSIBLE UPGRADE OF ADVY TO WARNING ACROSS THE KEWEENAW IN PARTICULAR. AFTER THE PERIOD OF STRONG ISENTROPIC ASCENT QUICKLY EXITS THIS EVENING...PCPN COVERAGE OVERNIGHT IS MUCH MORE UNCERTAIN WITH NO COHERENT FORCING. IN ANY EVENT...THE PCPN SHOULD BE MUCH LIGHTER IN THE WAKE OF THE MAIN BAND OF PCPN EXITING TO THE N AND E THIS EVENING. WITH THIS FCST ISSUANCE...OPTED TO INCLUDE THE REMAINDER OF THE FCST AREA (ALGER/DELTA/MENOMINEE COUNTIES EASTWARD) IN A WINTER WX ADVY LATE THIS AFTN/TONIGHT GIVEN THE EXPECTED MIXED PCPN AND 1-3 INCHES OF HVY/WET SNOW IN THAT AREA. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 436 AM EST SUN FEB 10 2013 AREA WILL BE IN THE MIDDLE OF THE SYSTEM PRODUCING A VARIETY OF WINTER PRECIPITATION TYPES. AT 12Z ON MONDAY...THE LOW SHOULD BE CENTERED OVER SOUTH CENTRAL UPPER MICHIGAN AND SHIFTING TO THE EAST-NORTHEAST THROUGH THE DAY. UPPER LEVEL DRY SLOT WILL BE EAST OF THE CWA AT THE START OF THE PERIOD AND WITH THE NEARLY VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL CWA...EXPECT THE HEAVIEST PRECIPITATION TO BE JUST TO THE NORTHWEST OF THE LOW CENTER...FROM THE KEWEENAW THROUGH GOGEBIC COUNTY WHERE THE LOWER LEVEL NOSE OF LINGERING WARM AIR WRAPPING NW AROUND THE LOW. MEANWHILE...THE REST OF THE AREA WILL BE SEEING LIGHT PRECIPITATION. THINK THERE WILL BE ENOUGH WARM AIR ON THE EAST SIDE OF THE LOW TO KEEP SOME MIXED PRECIPITATION GOING OVER EASTERN UPPER MICHIGAN DURING THE MORNING. AS THE LOW SHIFTS TO THE EAST AND COLDER AIR SURGES SOUTH IN THE AFTERNOON...SHOULD SEE A FAIRLY QUICK TRANSITION TO ALL SNOW FROM THE RAIN/FREEZING RAIN MIX. WITH THAT COLDER AIR MOVING IN...EXPECT A TRANSITION TO LAKE ENHANCED SNOW ON MONDAY. EXPECT IT TO OCCUR IN THE NORTH WIND FAVORED LOCATIONS DURING THE LATE MORNING OVER THE WEST AND THEN OVER THE EAST IN THE AFTERNOON. WITH MUCH OF THE CLOUD AT THE BOTTOM OR BELOW THE DGZ FOR MUCH OF MONDAY...DON/T THINK THE SNOW RATIOS WILL COME UP MUCH FROM THE 10-12 TO 1 RANGE UNTIL LATER IN THE AFTERNOON WHEN COLDER AIR ARRIVES. ANOTHER 2-4 INCHES IN THE FAVORED LOCATIONS OUT WEST SEEMS REASONABLE FOR MONDAY...WITH A DUSTING TO 2 INCHES IN OTHER LOCATIONS. AS FOR WINDS...THE TRACK OF THE LOW SHOULD LIMIT THE AMOUNT OF ENHANCEMENT FROM THE PRESSURE RISE/FALL COUPLET SINCE THE WINDS WILL BE PERPENDICULAR TO IT. THAT BEING SAID...NORTHERLY WINDS SHOULD BE ON THE INCREASE THROUGH THE DAY FROM WEST TO EAST AS COLDER AIR INCREASES THE LOW LEVEL LAPSE RATES. THINK THE HIGHEST GUSTS WILL BE RIGHT ALONG THE LAKE SUPERIOR SHORELINE AND WILL PROBABLY SEE A COUPLE HOUR PERIOD OF GUSTS IN THE 30-35MPH RANGE. MONDAY NIGHT INTO TUESDAY...H900 TEMPS AROUND -13C WILL BE ENOUGH TO HOLD ONTO LAKE ENHANCED/EFFECT SNOW INTO MONDAY EVENING. BUT...THE APPROACHING HIGH PRESSURE RIDGE WILL BE INCREASING THE DRY AIR AND SUBSIDENCE THROUGH THE NIGHT AND LOWER INVERSION HEIGHTS. IN ADDITION...EXPECT WARMER AIR TO ALSO MOVE SOUTHEAST INTO THE AREA AND REDUCE THE LAKE INSTABILITY. THUS...EXPECT THE INTENSITY OF THE SNOW TO DIMINISH THROUGH THE NIGHT WITH JUST LINGERING LIGHT SNOW SHOWERS BY TUESDAY MORNING IN THE FAVORED NORTHWEST WIND SNOW BELTS. CLOUDS WILL BE ON THE DECREASE THROUGH TUESDAY AFTERNOON WITH THE SURFACE RIDGE STARTING TO SHIFT TO THE EAST AND LOWER LEVEL WINDS BACKING TO THE WEST-SOUTHWEST. THIS IS IN RESPONSE TO THE NEXT SURFACE TROUGH THAT WILL BE CROSSING THE AREA TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE MORE DOMINATE SOUTHERN STREAM JET REMAINS OVER THE SOUTHERN THIRD OF THE CONUS. BEST MOISTURE/FORCING WITH THIS TROUGH AND SHORTWAVE LOOK TO STAY OVER THE NORTHEAST HALF OF LAKE SUPERIOR...BUT MAY BRUSH THE KEWEENAW AND FROM MARQUETTE TO NEWBERRY ON WEDNESDAY. EXTENDED RANGE MODELS BEGIN TO DIVERGE AFTER THIS POINT...AS A NORTHERN STREAM WAVE DIVES SOUTHEAST OUT OF ALBERTA AND INTO THE NORTHERN PLAINS ON WEDNESDAY. THIS WAVE CONTINUES TO DRIVE TO THE SOUTHEAST AND TRIES TO MERGE/PHASE WITH THE STRONGER SOUTHERN STREAM. 00Z GFS IS ON THE FARTHER NORTH AND LESS PHASED SOLUTION...WHILE THE 12Z ECMWF IS THE FARTHEST SOUTHEAST AND THE 12Z GEM IS IN BETWEEN. 00Z GEM/ECMWF DID TREND CLOSER TO THE GFS SOLUTION...SO WILL FOLLOW A GENERALLY BLEND AND HAVE THE ASSOCIATED SURFACE LOW TRACK THROUGH WISCONSIN. WOULD EXPECT SOME SHOWERS TO BE AFFECTING THE AREA ON THURSDAY AND WILL CONTINUE MENTION OF CHANCE/SLIGHT POPS. AFTER THURSDAY...GFS/GEM WRAP THE LOW UP AND HAVE IT SLOWLY DEPART THE GREAT LAKES REGION THROUGH FRIDAY NIGHT...WHILE THE ECMWF QUICKLY SLIDES IT EAST. WILL SPLIT THE DIFFERENCE AND HIGHLIGHT CHANCE POPS FOR MUCH OF THE AREA AND ESPECIALLY OVER THE LAKE EFFECT REGIONS SINCE THERE WILL BE A NORTHERLY COMPONENT TO THE WINDS AS H850 TEMPS FALL TO 14C ON FRIDAY. HIGH PRESSURE RIDGE WILL THEN TRY TO MOVE IN FOR FRIDAY NIGHT INTO SATURDAY AND HAVE GRADUALLY DIMINISHED THE LAKE EFFECT POPS. AFTER THE ABOVE NORMAL TEMPERATURES THROUGH WED/THURS...EXPECT A TRANSITION BACK TO MORE NORMAL TEMPERATURES FOR FRIDAY AND INTO THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 641 AM EST SUN FEB 10 2013 AT KIWD...IFR CIGS SHOULD RISE SLIGHTLY TO LOW MVFR THIS MORNING AS DOWNSLOPING E-SE WINDS STRENGTHEN. AT KCMX...EXPECT LOW MVFR CIGS TO PREVAIL INTO THE AFTN. ALTHOUGH UPSLOPING S-SE WINDS SHOULD WORK TO MAINTAIN IFR CIGS AT KSAW INTO THE AFTN...SOMEWHAT DRIER AIR WORKING INTO THE AREA MAY ALLOW CIGS TO RISE TO LOW MVFR. THIS AFTN... ATTENTION SHIFTS TO LOW PRES ADVANCING NE FROM THE CNTRL PLAINS. BAND OF PCPN...POSSIBLY MDT/HVY...WILL SWING NE...AFFECTING ALL TERMINALS FOR SEVERAL HRS DURING THE LATE AFTN/EARLY EVENING. PCPN SHOULD BE IN THE FORM OF SNOW...BUT SOME PL IS POSSIBLE AT KSAW. LIFR CONDITIONS ARE LIKELY TO PREVAIL AS THIS MAIN BAND OF PCPN LIFTS THRU THE AREA. LATER EVENING/OVERNIGHT...LIGHTER AND PROBABLY MORE INTERMITTENT PCPN IS EXPECTED THOUGH CONDITIONS WILL LIKELY REMAIN IFR/LIFR. SOME -FZDZ/-FZRA MAY OCCUR AT KSAW DURING THE NIGHT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 436 AM EST SUN FEB 10 2013 A LOW PRESSURE SYSTEM EXITING THE CENTRAL PLAINS WILL MOVE INTO THE UPPER GREAT LAKES REGION LATE TONIGHT AND THEN SHIFT EAST ON MONDAY AFTERNOON. THIS WILL LEAD TO INCREASING EAST-NORTHEAST FLOW OVER WESTERN LAKE SUPERIOR AND EXPECT GALES TO 40KTS THIS AFTERNOON AND EVENING. THUS...HAVE ISSUED A GALE WARNING FOR LSZ162/263. THEN AS THE WINDS TURN TO THE NORTH TONIGHT...EXPECT GALES TO 35-40KTS OVER THE WEST AND NORTH CENTRAL LAKE THROUGH MONDAY. THERE MAY BE GALES OVER THE EASTERN LAKE MONDAY AFTERNOON...BUT CONFIDENCE WASN/T HIGH ENOUGH TO ISSUE A GALE WARNING. A HIGH PRESSURE RIDGE WILL DIMINISH THE WINDS MONDAY NIGHT INTO TUESDAY. A SURFACE TROUGH WILL MOVE ACROSS LAKE SUPERIOR TUESDAY NIGHT AND WEDNESDAY...SHIFTING WINDS TO THE WEST BUT KEEPING THEM BELOW 20KTS. A WEAK LOW PRESSURE SYSTEM WILL THEN MOVE OUT OF THE DAKOTAS ON WEDNESDAY NIGHT AND INTO WISCONSIN ON THURSDAY. FREEZING SPRAY IS EXPECTED MONDAY AND MONDAY NIGHT OVER MUCH OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ006-007-012>014-085. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR MIZ002-009. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM EST MONDAY FOR MIZ001-003>005-084. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM CST MONDAY FOR MIZ010-011. LAKE SUPERIOR... GALE WARNING FROM 3 PM EST /2 PM CST/ THIS AFTERNOON TO 10 AM EST /9 AM CST/ MONDAY FOR LSZ162. GALE WARNING FROM 7 AM TO 7 PM EST MONDAY FOR LSZ264. GALE WARNING FROM 3 PM THIS AFTERNOON TO 4 PM EST MONDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ UPDATE...KF SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 AM EST SUN FEB 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 543 AM EST SUN FEB 10 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING OUT OVER THE WRN PLAINS...AND 00Z RAOBS AND SFC OBS INDICATE THAT SYSTEM HAS DEVELOPED A GOOD GULF MOISTURE CONNECTION. THE MID LEVEL LOW WILL TRACK NE...REACHING THE UPPER LAKES MON MORNING. ALTHOUGH MODELS ARE IN GOOD AGREEMENT ON THE TRACK OF THE MID LEVEL LOW AND ASSOCIATED SFC LOW...FCST REMAINS A CHALLENGE WITH RESPECT TO PTYPES AS EVAPORATIVE AND THEN DYNAMIC COOLING BATTLE STRONG WAA. WITH THE STRONG WAA REGIME TAPPING A SOLID GULF MOISTURE FEED...PRECIPITABLE WATER SURGES TO 250-300PCT OF NORMAL IN THE UPPER LAKES...PROVIDING POTENTIAL FOR HVY PCPN. HOWEVER... HEAVIEST PCPN WILL BE SHORT-LIVED (ABOUT 4-6HRS) ON THE FRONT SIDE OF THE SYSTEM AS STRONG ISENTROPIC ASCENT RAPIDLY SHIFTS ACROSS THE AREA PER 295K SFC WHICH SHOWS 40-50KT WINDS PERPENDICULAR TO ISOBARS. ALTHOUGH THERE IS ABUNDANT AVBL MOISTURE...QUICK MOVEMENT OF THIS VIGOROUS ASCENT WILL HELP KEEP PCPN TOTALS IN CHECK. NARROW MIDLEVEL DRY SLOT PUNCHING N COULD LEAD TO SOME CONVECTIVE PCPN ON TAIL END OF THE ISENTROPIC ASCENT/MAIN PCPN BAND THIS EVENING (MODELS ALSO SHOW SHOWALTER INDEX FALLING CLOSE TO 0C). AS FOR PTYPE...IT REMAINS A TOUGH CALL. FCST SOUNDINGS FROM THE NAM/GFS SHOW TEMP PROFILE HOVERING NEAR 0C THRU A RATHER SUBSTANTIAL LOW-LEVEL DEPTH...AND THE NAM IN PARTICULAR SHOWS SURGES OF ABOVE 0C TEMPS AT TIMES...SUGGESTING EPISODES OF VARYING PTYPES. WITH HIGH RES TEMP PROFILE INFO NOT AVBL FOR THE UKMET/REGIONAL GEM/UKMET/ECMWF...USE OF 850MB TEMPS AND 1000-850MB THICKNESS DOES NOT CLARIFY OR ADD ANY CERTAINTY TO THE PTYPE FCST. OF THOSE MODELS...THE REGIONAL GEM IS QUITE WARM IN THE LOW-LEVELS AS IT HAS 1000-850MB THICKNESS RISING ABOVE 1300M TONIGHT ACROSS NEARLY THE ENTIRE FCST AREA AND AS HIGH AS 1320M ACROSS THE SCNTRL/SE FCST AREA. IF CORRECT...PCPN WOULD CHANGE TO MOSTLY RA/FZRA OVER MUCH OF THE AREA. AT THIS POINT...WILL INCLUDE MIXED PTYPES ROUGHLY SE OF A MARQUETTE TO CRYSTAL FALLS LINE. IT MAY BE ONE OF THOSE EVENTS WHERE PCPN IS MOSTLY SNOW DURING PERIOD OF STRONGEST FORCING/HEAVIEST PCPN AND THEN MORE OF A MIX OR A TRANSITION TO LIQUID PTYPES DURING PERIODS OF LIGHT PCPN. MIXING RATIOS SOLIDLY AROUND 4G/KG ON THE 295K SFC AND ABOUT 6 HRS OF STRONG ISENTROPIC ASCENT SUGGEST POTENTIAL FOR AROUND 4 INCHES OF SNOW WHERE PTYPE IS EXCLUSIVELY SNOW. THE SNOW WILL BE WET/HVY DUE TO A NARROW AND HIGH DGZ (SNOW-TO-WATER WILL PROBABLY BE DOWN AROUND 10 TO 1). STRONGER DEEP LAYER FORCING PER QVECTORS WILL PASS ACROSS THE NW FCST AREA...SO TOTALS THERE MAY BE HIGHER. IN FACT OVER THE NW...SNOW AMOUNTS WILL BE CLOSE TO THE WARNING CRITERIA OF 6 INCHES/12HR FOR LOW SNOW TO WATER RATIO SNOW. LATER SHIFTS WILL NEED TO MONITOR FOR POSSIBLE UPGRADE OF ADVY TO WARNING ACROSS THE KEWEENAW IN PARTICULAR. AFTER THE PERIOD OF STRONG ISENTROPIC ASCENT QUICKLY EXITS THIS EVENING...PCPN COVERAGE OVERNIGHT IS MUCH MORE UNCERTAIN WITH NO COHERENT FORCING. IN ANY EVENT...THE PCPN SHOULD BE MUCH LIGHTER IN THE WAKE OF THE MAIN BAND OF PCPN EXITING TO THE N AND E THIS EVENING. WITH THIS FCST ISSUANCE...OPTED TO INCLUDE THE REMAINDER OF THE FCST AREA (ALGER/DELTA/MENOMINEE COUNTIES EASTWARD) IN A WINTER WX ADVY LATE THIS AFTN/TONIGHT GIVEN THE EXPECTED MIXED PCPN AND 1-3 INCHES OF HVY/WET SNOW IN THAT AREA. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 436 AM EST SUN FEB 10 2013 AREA WILL BE IN THE MIDDLE OF THE SYSTEM PRODUCING A VARIETY OF WINTER PRECIPITATION TYPES. AT 12Z ON MONDAY...THE LOW SHOULD BE CENTERED OVER SOUTH CENTRAL UPPER MICHIGAN AND SHIFTING TO THE EAST-NORTHEAST THROUGH THE DAY. UPPER LEVEL DRY SLOT WILL BE EAST OF THE CWA AT THE START OF THE PERIOD AND WITH THE NEARLY VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL CWA...EXPECT THE HEAVIEST PRECIPITATION TO BE JUST TO THE NORTHWEST OF THE LOW CENTER...FROM THE KEWEENAW THROUGH GOGEBIC COUNTY WHERE THE LOWER LEVEL NOSE OF LINGERING WARM AIR WRAPPING NW AROUND THE LOW. MEANWHILE...THE REST OF THE AREA WILL BE SEEING LIGHT PRECIPITATION. THINK THERE WILL BE ENOUGH WARM AIR ON THE EAST SIDE OF THE LOW TO KEEP SOME MIXED PRECIPITATION GOING OVER EASTERN UPPER MICHIGAN DURING THE MORNING. AS THE LOW SHIFTS TO THE EAST AND COLDER AIR SURGES SOUTH IN THE AFTERNOON...SHOULD SEE A FAIRLY QUICK TRANSITION TO ALL SNOW FROM THE RAIN/FREEZING RAIN MIX. WITH THAT COLDER AIR MOVING IN...EXPECT A TRANSITION TO LAKE ENHANCED SNOW ON MONDAY. EXPECT IT TO OCCUR IN THE NORTH WIND FAVORED LOCATIONS DURING THE LATE MORNING OVER THE WEST AND THEN OVER THE EAST IN THE AFTERNOON. WITH MUCH OF THE CLOUD AT THE BOTTOM OR BELOW THE DGZ FOR MUCH OF MONDAY...DON/T THINK THE SNOW RATIOS WILL COME UP MUCH FROM THE 10-12 TO 1 RANGE UNTIL LATER IN THE AFTERNOON WHEN COLDER AIR ARRIVES. ANOTHER 2-4 INCHES IN THE FAVORED LOCATIONS OUT WEST SEEMS REASONABLE FOR MONDAY...WITH A DUSTING TO 2 INCHES IN OTHER LOCATIONS. AS FOR WINDS...THE TRACK OF THE LOW SHOULD LIMIT THE AMOUNT OF ENHANCEMENT FROM THE PRESSURE RISE/FALL COUPLET SINCE THE WINDS WILL BE PERPENDICULAR TO IT. THAT BEING SAID...NORTHERLY WINDS SHOULD BE ON THE INCREASE THROUGH THE DAY FROM WEST TO EAST AS COLDER AIR INCREASES THE LOW LEVEL LAPSE RATES. THINK THE HIGHEST GUSTS WILL BE RIGHT ALONG THE LAKE SUPERIOR SHORELINE AND WILL PROBABLY SEE A COUPLE HOUR PERIOD OF GUSTS IN THE 30-35MPH RANGE. MONDAY NIGHT INTO TUESDAY...H900 TEMPS AROUND -13C WILL BE ENOUGH TO HOLD ONTO LAKE ENHANCED/EFFECT SNOW INTO MONDAY EVENING. BUT...THE APPROACHING HIGH PRESSURE RIDGE WILL BE INCREASING THE DRY AIR AND SUBSIDENCE THROUGH THE NIGHT AND LOWER INVERSION HEIGHTS. IN ADDITION...EXPECT WARMER AIR TO ALSO MOVE SOUTHEAST INTO THE AREA AND REDUCE THE LAKE INSTABILITY. THUS...EXPECT THE INTENSITY OF THE SNOW TO DIMINISH THROUGH THE NIGHT WITH JUST LINGERING LIGHT SNOW SHOWERS BY TUESDAY MORNING IN THE FAVORED NORTHWEST WIND SNOW BELTS. CLOUDS WILL BE ON THE DECREASE THROUGH TUESDAY AFTERNOON WITH THE SURFACE RIDGE STARTING TO SHIFT TO THE EAST AND LOWER LEVEL WINDS BACKING TO THE WEST-SOUTHWEST. THIS IS IN RESPONSE TO THE NEXT SURFACE TROUGH THAT WILL BE CROSSING THE AREA TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE MORE DOMINATE SOUTHERN STREAM JET REMAINS OVER THE SOUTHERN THIRD OF THE CONUS. BEST MOISTURE/FORCING WITH THIS TROUGH AND SHORTWAVE LOOK TO STAY OVER THE NORTHEAST HALF OF LAKE SUPERIOR...BUT MAY BRUSH THE KEWEENAW AND FROM MARQUETTE TO NEWBERRY ON WEDNESDAY. EXTENDED RANGE MODELS BEGIN TO DIVERGE AFTER THIS POINT...AS A NORTHERN STREAM WAVE DIVES SOUTHEAST OUT OF ALBERTA AND INTO THE NORTHERN PLAINS ON WEDNESDAY. THIS WAVE CONTINUES TO DRIVE TO THE SOUTHEAST AND TRIES TO MERGE/PHASE WITH THE STRONGER SOUTHERN STREAM. 00Z GFS IS ON THE FARTHER NORTH AND LESS PHASED SOLUTION...WHILE THE 12Z ECMWF IS THE FARTHEST SOUTHEAST AND THE 12Z GEM IS IN BETWEEN. 00Z GEM/ECMWF DID TREND CLOSER TO THE GFS SOLUTION...SO WILL FOLLOW A GENERALLY BLEND AND HAVE THE ASSOCIATED SURFACE LOW TRACK THROUGH WISCONSIN. WOULD EXPECT SOME SHOWERS TO BE AFFECTING THE AREA ON THURSDAY AND WILL CONTINUE MENTION OF CHANCE/SLIGHT POPS. AFTER THURSDAY...GFS/GEM WRAP THE LOW UP AND HAVE IT SLOWLY DEPART THE GREAT LAKES REGION THROUGH FRIDAY NIGHT...WHILE THE ECMWF QUICKLY SLIDES IT EAST. WILL SPLIT THE DIFFERENCE AND HIGHLIGHT CHANCE POPS FOR MUCH OF THE AREA AND ESPECIALLY OVER THE LAKE EFFECT REGIONS SINCE THERE WILL BE A NORTHERLY COMPONENT TO THE WINDS AS H850 TEMPS FALL TO 14C ON FRIDAY. HIGH PRESSURE RIDGE WILL THEN TRY TO MOVE IN FOR FRIDAY NIGHT INTO SATURDAY AND HAVE GRADUALLY DIMINISHED THE LAKE EFFECT POPS. AFTER THE ABOVE NORMAL TEMPERATURES THROUGH WED/THURS...EXPECT A TRANSITION BACK TO MORE NORMAL TEMPERATURES FOR FRIDAY AND INTO THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 641 AM EST SUN FEB 10 2013 AT KIWD...IFR CIGS SHOULD RISE SLIGHTLY TO LOW MVFR THIS MORNING AS DOWNSLOPING E-SE WINDS STRENGTHEN. AT KCMX...EXPECT LOW MVFR CIGS TO PREVAIL INTO THE AFTN. ALTHOUGH UPSLOPING S-SE WINDS SHOULD WORK TO MAINTAIN IFR CIGS AT KSAW INTO THE AFTN...SOMEWHAT DRIER AIR WORKING INTO THE AREA MAY ALLOW CIGS TO RISE TO LOW MVFR. THIS AFTN... ATTENTION SHIFTS TO LOW PRES ADVANCING NE FROM THE CNTRL PLAINS. BAND OF PCPN...POSSIBLY MDT/HVY...WILL SWING NE...AFFECTING ALL TERMINALS FOR SEVERAL HRS DURING THE LATE AFTN/EARLY EVENING. PCPN SHOULD BE IN THE FORM OF SNOW...BUT SOME PL IS POSSIBLE AT KSAW. LIFR CONDITIONS ARE LIKELY TO PREVAIL AS THIS MAIN BAND OF PCPN LIFTS THRU THE AREA. LATER EVENING/OVERNIGHT...LIGHTER AND PROBABLY MORE INTERMITTENT PCPN IS EXPECTED THOUGH CONDITIONS WILL LIKELY REMAIN IFR/LIFR. SOME -FZDZ/-FZRA MAY OCCUR AT KSAW DURING THE NIGHT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 436 AM EST SUN FEB 10 2013 A LOW PRESSURE SYSTEM EXITING THE CENTRAL PLAINS WILL MOVE INTO THE UPPER GREAT LAKES REGION LATE TONIGHT AND THEN SHIFT EAST ON MONDAY AFTERNOON. THIS WILL LEAD TO INCREASING EAST-NORTHEAST FLOW OVER WESTERN LAKE SUPERIOR AND EXPECT GALES TO 40KTS THIS AFTERNOON AND EVENING. THUS...HAVE ISSUED A GALE WARNING FOR LSZ162/263. THEN AS THE WINDS TURN TO THE NORTH TONIGHT...EXPECT GALES TO 35-40KTS OVER THE WEST AND NORTH CENTRAL LAKE THROUGH MONDAY. THERE MAY BE GALES OVER THE EASTERN LAKE MONDAY AFTERNOON...BUT CONFIDENCE WASN/T HIGH ENOUGH TO ISSUE A GALE WARNING. A HIGH PRESSURE RIDGE WILL DIMINISH THE WINDS MONDAY NIGHT INTO TUESDAY. A SURFACE TROUGH WILL MOVE ACROSS LAKE SUPERIOR TUESDAY NIGHT AND WEDNESDAY...SHIFTING WINDS TO THE WEST BUT KEEPING THEM BELOW 20KTS. A WEAK LOW PRESSURE SYSTEM WILL THEN MOVE OUT OF THE DAKOTAS ON WEDNESDAY NIGHT AND INTO WISCONSIN ON THURSDAY. FREEZING SPRAY IS EXPECTED MONDAY AND MONDAY NIGHT OVER MUCH OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ006-007-012>014-085. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR MIZ002-009. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM EST MONDAY FOR MIZ001-003>005-084. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM CST MONDAY FOR MIZ010-011. LAKE SUPERIOR... GALE WARNING FROM 3 PM EST /2 PM CST/ THIS AFTERNOON TO 10 AM EST /9 AM CST/ MONDAY FOR LSZ162. GALE WARNING FROM 7 AM TO 7 PM EST MONDAY FOR LSZ264. GALE WARNING FROM 3 PM THIS AFTERNOON TO 4 PM EST MONDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
544 AM EST SUN FEB 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 543 AM EST SUN FEB 10 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING OUT OVER THE WRN PLAINS...AND 00Z RAOBS AND SFC OBS INDICATE THAT SYSTEM HAS DEVELOPED A GOOD GULF MOISTURE CONNECTION. THE MID LEVEL LOW WILL TRACK NE...REACHING THE UPPER LAKES MON MORNING. ALTHOUGH MODELS ARE IN GOOD AGREEMENT ON THE TRACK OF THE MID LEVEL LOW AND ASSOCIATED SFC LOW...FCST REMAINS A CHALLENGE WITH RESPECT TO PTYPES AS EVAPORATIVE AND THEN DYNAMIC COOLING BATTLE STRONG WAA. WITH THE STRONG WAA REGIME TAPPING A SOLID GULF MOISTURE FEED...PRECIPITABLE WATER SURGES TO 250-300PCT OF NORMAL IN THE UPPER LAKES...PROVIDING POTENTIAL FOR HVY PCPN. HOWEVER... HEAVIEST PCPN WILL BE SHORT-LIVED (ABOUT 4-6HRS) ON THE FRONT SIDE OF THE SYSTEM AS STRONG ISENTROPIC ASCENT RAPIDLY SHIFTS ACROSS THE AREA PER 295K SFC WHICH SHOWS 40-50KT WINDS PERPENDICULAR TO ISOBARS. ALTHOUGH THERE IS ABUNDANT AVBL MOISTURE...QUICK MOVEMENT OF THIS VIGOROUS ASCENT WILL HELP KEEP PCPN TOTALS IN CHECK. NARROW MIDLEVEL DRY SLOT PUNCHING N COULD LEAD TO SOME CONVECTIVE PCPN ON TAIL END OF THE ISENTROPIC ASCENT/MAIN PCPN BAND THIS EVENING (MODELS ALSO SHOW SHOWALTER INDEX FALLING CLOSE TO 0C). AS FOR PTYPE...IT REMAINS A TOUGH CALL. FCST SOUNDINGS FROM THE NAM/GFS SHOW TEMP PROFILE HOVERING NEAR 0C THRU A RATHER SUBSTANTIAL LOW-LEVEL DEPTH...AND THE NAM IN PARTICULAR SHOWS SURGES OF ABOVE 0C TEMPS AT TIMES...SUGGESTING EPISODES OF VARYING PTYPES. WITH HIGH RES TEMP PROFILE INFO NOT AVBL FOR THE UKMET/REGIONAL GEM/UKMET/ECMWF...USE OF 850MB TEMPS AND 1000-850MB THICKNESS DOES NOT CLARIFY OR ADD ANY CERTAINTY TO THE PTYPE FCST. OF THOSE MODELS...THE REGIONAL GEM IS QUITE WARM IN THE LOW-LEVELS AS IT HAS 1000-850MB THICKNESS RISING ABOVE 1300M TONIGHT ACROSS NEARLY THE ENTIRE FCST AREA AND AS HIGH AS 1320M ACROSS THE SCNTRL/SE FCST AREA. IF CORRECT...PCPN WOULD CHANGE TO MOSTLY RA/FZRA OVER MUCH OF THE AREA. AT THIS POINT...WILL INCLUDE MIXED PTYPES ROUGHLY SE OF A MARQUETTE TO CRYSTAL FALLS LINE. IT MAY BE ONE OF THOSE EVENTS WHERE PCPN IS MOSTLY SNOW DURING PERIOD OF STRONGEST FORCING/HEAVIEST PCPN AND THEN MORE OF A MIX OR A TRANSITION TO LIQUID PTYPES DURING PERIODS OF LIGHT PCPN. MIXING RATIOS SOLIDLY AROUND 4G/KG ON THE 295K SFC AND ABOUT 6 HRS OF STRONG ISENTROPIC ASCENT SUGGEST POTENTIAL FOR AROUND 4 INCHES OF SNOW WHERE PTYPE IS EXCLUSIVELY SNOW. THE SNOW WILL BE WET/HVY DUE TO A NARROW AND HIGH DGZ (SNOW-TO-WATER WILL PROBABLY BE DOWN AROUND 10 TO 1). STRONGER DEEP LAYER FORCING PER QVECTORS WILL PASS ACROSS THE NW FCST AREA...SO TOTALS THERE MAY BE HIGHER. IN FACT OVER THE NW...SNOW AMOUNTS WILL BE CLOSE TO THE WARNING CRITERIA OF 6 INCHES/12HR FOR LOW SNOW TO WATER RATIO SNOW. LATER SHIFTS WILL NEED TO MONITOR FOR POSSIBLE UPGRADE OF ADVY TO WARNING ACROSS THE KEWEENAW IN PARTICULAR. AFTER THE PERIOD OF STRONG ISENTROPIC ASCENT QUICKLY EXITS THIS EVENING...PCPN COVERAGE OVERNIGHT IS MUCH MORE UNCERTAIN WITH NO COHERENT FORCING. IN ANY EVENT...THE PCPN SHOULD BE MUCH LIGHTER IN THE WAKE OF THE MAIN BAND OF PCPN EXITING TO THE N AND E THIS EVENING. WITH THIS FCST ISSUANCE...OPTED TO INCLUDE THE REMAINDER OF THE FCST AREA (ALGER/DELTA/MENOMINEE COUNTIES EASTWARD) IN A WINTER WX ADVY LATE THIS AFTN/TONIGHT GIVEN THE EXPECTED MIXED PCPN AND 1-3 INCHES OF HVY/WET SNOW IN THAT AREA. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 436 AM EST SUN FEB 10 2013 AREA WILL BE IN THE MIDDLE OF THE SYSTEM PRODUCING A VARIETY OF WINTER PRECIPITATION TYPES. AT 12Z ON MONDAY...THE LOW SHOULD BE CENTERED OVER SOUTH CENTRAL UPPER MICHIGAN AND SHIFTING TO THE EAST-NORTHEAST THROUGH THE DAY. UPPER LEVEL DRY SLOT WILL BE EAST OF THE CWA AT THE START OF THE PERIOD AND WITH THE NEARLY VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL CWA...EXPECT THE HEAVIEST PRECIPITATION TO BE JUST TO THE NORTHWEST OF THE LOW CENTER...FROM THE KEWEENAW THROUGH GOGEBIC COUNTY WHERE THE LOWER LEVEL NOSE OF LINGERING WARM AIR WRAPPING NW AROUND THE LOW. MEANWHILE...THE REST OF THE AREA WILL BE SEEING LIGHT PRECIPITATION. THINK THERE WILL BE ENOUGH WARM AIR ON THE EAST SIDE OF THE LOW TO KEEP SOME MIXED PRECIPITATION GOING OVER EASTERN UPPER MICHIGAN DURING THE MORNING. AS THE LOW SHIFTS TO THE EAST AND COLDER AIR SURGES SOUTH IN THE AFTERNOON...SHOULD SEE A FAIRLY QUICK TRANSITION TO ALL SNOW FROM THE RAIN/FREEZING RAIN MIX. WITH THAT COLDER AIR MOVING IN...EXPECT A TRANSITION TO LAKE ENHANCED SNOW ON MONDAY. EXPECT IT TO OCCUR IN THE NORTH WIND FAVORED LOCATIONS DURING THE LATE MORNING OVER THE WEST AND THEN OVER THE EAST IN THE AFTERNOON. WITH MUCH OF THE CLOUD AT THE BOTTOM OR BELOW THE DGZ FOR MUCH OF MONDAY...DON/T THINK THE SNOW RATIOS WILL COME UP MUCH FROM THE 10-12 TO 1 RANGE UNTIL LATER IN THE AFTERNOON WHEN COLDER AIR ARRIVES. ANOTHER 2-4 INCHES IN THE FAVORED LOCATIONS OUT WEST SEEMS REASONABLE FOR MONDAY...WITH A DUSTING TO 2 INCHES IN OTHER LOCATIONS. AS FOR WINDS...THE TRACK OF THE LOW SHOULD LIMIT THE AMOUNT OF ENHANCEMENT FROM THE PRESSURE RISE/FALL COUPLET SINCE THE WINDS WILL BE PERPENDICULAR TO IT. THAT BEING SAID...NORTHERLY WINDS SHOULD BE ON THE INCREASE THROUGH THE DAY FROM WEST TO EAST AS COLDER AIR INCREASES THE LOW LEVEL LAPSE RATES. THINK THE HIGHEST GUSTS WILL BE RIGHT ALONG THE LAKE SUPERIOR SHORELINE AND WILL PROBABLY SEE A COUPLE HOUR PERIOD OF GUSTS IN THE 30-35MPH RANGE. MONDAY NIGHT INTO TUESDAY...H900 TEMPS AROUND -13C WILL BE ENOUGH TO HOLD ONTO LAKE ENHANCED/EFFECT SNOW INTO MONDAY EVENING. BUT...THE APPROACHING HIGH PRESSURE RIDGE WILL BE INCREASING THE DRY AIR AND SUBSIDENCE THROUGH THE NIGHT AND LOWER INVERSION HEIGHTS. IN ADDITION...EXPECT WARMER AIR TO ALSO MOVE SOUTHEAST INTO THE AREA AND REDUCE THE LAKE INSTABILITY. THUS...EXPECT THE INTENSITY OF THE SNOW TO DIMINISH THROUGH THE NIGHT WITH JUST LINGERING LIGHT SNOW SHOWERS BY TUESDAY MORNING IN THE FAVORED NORTHWEST WIND SNOW BELTS. CLOUDS WILL BE ON THE DECREASE THROUGH TUESDAY AFTERNOON WITH THE SURFACE RIDGE STARTING TO SHIFT TO THE EAST AND LOWER LEVEL WINDS BACKING TO THE WEST-SOUTHWEST. THIS IS IN RESPONSE TO THE NEXT SURFACE TROUGH THAT WILL BE CROSSING THE AREA TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE MORE DOMINATE SOUTHERN STREAM JET REMAINS OVER THE SOUTHERN THIRD OF THE CONUS. BEST MOISTURE/FORCING WITH THIS TROUGH AND SHORTWAVE LOOK TO STAY OVER THE NORTHEAST HALF OF LAKE SUPERIOR...BUT MAY BRUSH THE KEWEENAW AND FROM MARQUETTE TO NEWBERRY ON WEDNESDAY. EXTENDED RANGE MODELS BEGIN TO DIVERGE AFTER THIS POINT...AS A NORTHERN STREAM WAVE DIVES SOUTHEAST OUT OF ALBERTA AND INTO THE NORTHERN PLAINS ON WEDNESDAY. THIS WAVE CONTINUES TO DRIVE TO THE SOUTHEAST AND TRIES TO MERGE/PHASE WITH THE STRONGER SOUTHERN STREAM. 00Z GFS IS ON THE FARTHER NORTH AND LESS PHASED SOLUTION...WHILE THE 12Z ECMWF IS THE FARTHEST SOUTHEAST AND THE 12Z GEM IS IN BETWEEN. 00Z GEM/ECMWF DID TREND CLOSER TO THE GFS SOLUTION...SO WILL FOLLOW A GENERALLY BLEND AND HAVE THE ASSOCIATED SURFACE LOW TRACK THROUGH WISCONSIN. WOULD EXPECT SOME SHOWERS TO BE AFFECTING THE AREA ON THURSDAY AND WILL CONTINUE MENTION OF CHANCE/SLIGHT POPS. AFTER THURSDAY...GFS/GEM WRAP THE LOW UP AND HAVE IT SLOWLY DEPART THE GREAT LAKES REGION THROUGH FRIDAY NIGHT...WHILE THE ECMWF QUICKLY SLIDES IT EAST. WILL SPLIT THE DIFFERENCE AND HIGHLIGHT CHANCE POPS FOR MUCH OF THE AREA AND ESPECIALLY OVER THE LAKE EFFECT REGIONS SINCE THERE WILL BE A NORTHERLY COMPONENT TO THE WINDS AS H850 TEMPS FALL TO 14C ON FRIDAY. HIGH PRESSURE RIDGE WILL THEN TRY TO MOVE IN FOR FRIDAY NIGHT INTO SATURDAY AND HAVE GRADUALLY DIMINISHED THE LAKE EFFECT POPS. AFTER THE ABOVE NORMAL TEMPERATURES THROUGH WED/THURS...EXPECT A TRANSITION BACK TO MORE NORMAL TEMPERATURES FOR FRIDAY AND INTO THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1209 AM EST SUN FEB 10 2013 LOWER END MVFR CIGS ARE EXPECTED OVERNIGHT AS LOW LEVEL MOISTURE CONTINUES TO MOVE INTO THE REGION ON SRLY FLOW. A MORE SSE TRAJECTORY LATE IN THE NIGHT AT SAW SHOULD HELP LOWER CIGS INTO THE IFR RANGE ALONG WITH MVFR VSBY IN BR. DOWNSLOPE FLOW AT IWD AND CMX WILL HELP KEEP CIGS FROM DROPPING OFF AS MUCH. BY MID TO LATE AFTERNOON...SNOW MIXED WITH SLEET IS EXPECTED TO SPREAD NE INTO UPPER MI DROPPING BOTH CIG AND VSBY INTO THE IFR RANGE. THERE IS ALSO A POTENTIAL FOR SOME FREEZING RAIN BUT THE PROBABILITY WAS LOW ENOUGH TO LEAVE OUT MENTION IN THE TAF AT THIS TIME. A PERIOD OF HEAVIER PCPN...MAINLY SNOW...IS LIKELY TO HELP LOWER CIGS INTO THE LIFR RANGE DURING THE EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 436 AM EST SUN FEB 10 2013 A LOW PRESSURE SYSTEM EXITING THE CENTRAL PLAINS WILL MOVE INTO THE UPPER GREAT LAKES REGION LATE TONIGHT AND THEN SHIFT EAST ON MONDAY AFTERNOON. THIS WILL LEAD TO INCREASING EAST-NORTHEAST FLOW OVER WESTERN LAKE SUPERIOR AND EXPECT GALES TO 40KTS THIS AFTERNOON AND EVENING. THUS...HAVE ISSUED A GALE WARNING FOR LSZ162/263. THEN AS THE WINDS TURN TO THE NORTH TONIGHT...EXPECT GALES TO 35-40KTS OVER THE WEST AND NORTH CENTRAL LAKE THROUGH MONDAY. THERE MAY BE GALES OVER THE EASTERN LAKE MONDAY AFTERNOON...BUT CONFIDENCE WASN/T HIGH ENOUGH TO ISSUE A GALE WARNING. A HIGH PRESSURE RIDGE WILL DIMINISH THE WINDS MONDAY NIGHT INTO TUESDAY. A SURFACE TROUGH WILL MOVE ACROSS LAKE SUPERIOR TUESDAY NIGHT AND WEDNESDAY...SHIFTING WINDS TO THE WEST BUT KEEPING THEM BELOW 20KTS. A WEAK LOW PRESSURE SYSTEM WILL THEN MOVE OUT OF THE DAKOTAS ON WEDNESDAY NIGHT AND INTO WISCONSIN ON THURSDAY. FREEZING SPRAY IS EXPECTED MONDAY AND MONDAY NIGHT OVER MUCH OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ006-007-012>014-085. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR MIZ002-009. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM EST MONDAY FOR MIZ001-003>005-084. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM CST MONDAY FOR MIZ010-011. LAKE SUPERIOR... GALE WARNING FROM 3 PM EST /2 PM CST/ THIS AFTERNOON TO 10 AM EST /9 AM CST/ MONDAY FOR LSZ162. GALE WARNING FROM 7 AM TO 7 PM EST MONDAY FOR LSZ264. GALE WARNING FROM 3 PM THIS AFTERNOON TO 4 PM EST MONDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
1257 AM EST SUN FEB 10 2013 .SYNOPSIS... ISSUED AT 420 PM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO ALL SNOW ON MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. MAINLY QUIET WEATHER WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK...WITH SEASONAL TEMPERATURES EXPECTED. && .UPDATE... ISSUED AT 1255 AM EST SUN FEB 10 2013 UPDATES THIS HOUR: VERY MINOR CHANGES TO SKY COVER OVER NW LOWER WITH SOMEWHAT LARGER ADJUSTMENTS TO TEMPERATURES BASED ON VERY LARGE SPREAD ACROSS THE CWA /-4 IN ALGER ATTM WITH THE COAST OF NW LOWER IN THE MID-UPPER 20S/. EXPECT THE COOL SPOTS TO GRADUALLY RE-COUPLE AND WARM OVER THE NEXT FEW HOURS...BUT OTHERWISE... QUIET WEATHER CONTINUES THROUGH DAYBREAK. UPDATE ISSUED AT 742 PM EST SAT FEB 9 2013 MADE SOME EARLY TWEAKS TO FORECAST. COMBINATION OF SHALLOW LAKE CLOUDS OVER LAKE MICHIGAN AND PATCHY MID LEVEL AC WILL TEND TO KEEP EASTERN UPPER ON THE CLOUDY SIDE OVERNIGHT (ASSUMING LAKE MICHIGAN CLOUDS GET ADVECTED EASTWARD A BIT). AT THE SAME TIME... CURRENTLY NOT AS CONCERNED WITH LOW CLOUDS SPILLING INTO NORTHWEST LOWER WITH STRENGTHENING SOUTHEAST SURFACE FLOW OVER THE LOWER PENINSULA. BOTH RAP AND NAM-WRF HAVING BOUNDARY LAYER ISSUES...RAP FORECAST SOUNDINGS TOO COLD (SUGGESTING IT SHOULD ALREADY BE IN THE MID TEENS AT GLR/GOV/CAD WHEN IN REALITY TEMPERATURES ARE 8-10F WARMER)...AND NAM-WRF SOUNDINGS ARE TOO MOIST. THINK THERE WILL BE ENOUGH OF A GRADIENT TO KEEP THINGS FROM DE-COUPLING AND RADIATING LIKE MAD. SO HAVE NUDGED TEMPERATURE TRENDS UP A BIT (AND MINIMUM TEMPERATURES BY EXTENSION). && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 420 PM EST SAT FEB 9 2013 ELONGATED SFC RIDGE AXIS JUST OFF TO THE EAST OF THE STATE THIS AFTERNOON WITH SOUTHERLY RETURN FLOW STRENGTHENING ACROSS THE STATE. ABUNDANT SUN ACROSS NRN LOWER MICHIGAN TODAY. REMAINING LAKE CLOUDS OVER LAKE MICHIGAN STILL STILL JUST OFFSHORE OF LOWER MICHIGAN BUT SHOWING A LITTLE SIGN OF INCHING BACK TOWARD SHORE. UPPER MICHIGAN GETTING RIPPED OFF HOWEVER...AS SOUTHERLY MEAN LOW LEVEL WIND IS DRAGGING LAKE CLOUDS UP THROUGH A GOOD PART OF EASTERN UPPER. KERY REPORTED 5SM -SN ABOUT TWO HOURS AGO. SO...STILL GETTING SOME SHALLOW NUISANCE LAKE SNOWS. TONIGHT...MORE NUISANCE STUFF TO WORRY ABOUT THAN ANYTHING. LAKE CLOUDS OVER SRN LAKE MICHIGAN ARE STARTING TO ERODE FROM THE SOUTH AS WARMER LOW LEVEL AIR MAKES ITS WAY UP THE LAKE. HOWEVER...STILL A WINDOW OF OPPORTUNITY TO GET SOME LAKE CLOUDS INTO THE PARTS OF NW LOWER MICHIGAN THIS EVENING AS WE GET MORE OF A WESTERLY COMPONENT TO THE WIND...ALTHOUGH REMAINING LAKE CLOUDS SHOULD FURTHER ERODE AWAY FROM THE SOUTH AS WARMER LOW LEVEL AIR WORKS INTO REGION. SECOND PROBLEM IS STRATUS AND/OR FOG POTENTIAL. AS WE GET MORE OF A WESTERLY COMPONENT OFF LAKE MICHIGAN...FORECAST SOUNDINGS SHOW ADDITIONAL MOISTURE GETTING PULLED INTO NRN LOWER MICHIGAN THROUGH THE NIGHT (DEW POINT TRACE FOLDS OVER-TOP THE BOUNDARY LAYER). THIS SUGGESTS THE POSSIBILITY OF DEVELOPMENT OF LOW STRATUS AND/OR FOG AS WARM/MOIST LAYER ALOFT ADVECTS OVER A COLD BOUNDARY LAYER. DIDN`T GO MOSTLY CLOUDY...BUT DO HAVE AN INCREASE IN CLOUD COVER (PARTLY CLOUDY) THIS EVENING. TEMPS...YET ANOTHER ISSUE. HAVE MAINLY CLEAR SKIES INTERIOR GOING INTO THE EVENING WHICH WILL ALLOW TEMPS TO DROP QUICKLY AGAIN. BUT TEMP FREE-FALL WILL BE THROTTLED COMPARED TO LAST NIGHT BY STRONGER FLOW OFF THE SFC. DON`T FORESEE BELOW ZERO READINGS TONIGHT GIVEN THE STRONGER WINDS AND CLOUD POTENTIAL...BUT SOME OF THE COLDER SPOTS DIPPING INTO THE SINGLE DIGITS CERTAINLY NOT OUT OF THE QUESTION. SUNDAY...ANY CIGS/FOG WILL ERODE DURING THE MORNING HOURS AS WARMER AIR CONTINUES TO WORK INTO THE REGION. NEXT WEATHER MAKER WILL BE WORKING INTO THE MIDWEST THROUGH THE COURSE OF THE DAY. STRONG PULSE OF WARM ADVECTION EXPECTED TO PUSH PRECIP UP THROUGH THE STATE... GENERALLY BETWEEN THE 21Z AND 00Z TIME FRAME (MODEL CONSENSUS IS PRETTY CLOSE)...WHICH SEEMS REASONABLE GIVEN THE VERY DRY AIR IN PLACE DOWNSTAIRS INITIALLY. BUT ONCE AGAIN...WARM NOSE ALOFT ROCKETING INTO THE REGION WILL ALSO BRING ANOTHER ROUND OF P-TYPE ISSUES TO NORTHERN MICHIGAN. COLD TEMPS TO START AND SFC TEMPS JUST INCHING TO AROUND THE FREEZING MARK WILL PRESENT A RAIN/FREEZING RAIN PROBLEM OVER THE HIGH TERRAIN/NE LOWER MICHIGAN. SNOW/SLEET/ FREEZING RAIN MIX IN EASTERN UPPER WITH SLIGHTLY COLDER AIR ALOFT. DON`T THINK WE GET WARNING CRITERIA PRECIP OF ANY TYPE. BUT MAY ULTIMATELY NEED SOME ADVISORIES ISSUED...BUT WILL ALLOW LATER SHIFTS TO TAKE CARE OF THAT. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 420 PM EST SAT FEB 9 2013 PROGRESSIVE PATTERN SET TO CONTINUE...COURTESY OF ONE AGITATED PACIFIC PATTERN (WHICH WATER VAPOR IMAGERY SHOWS COVERED WITH A VIRTUAL WAVE-TRAIN OF STRONG TROUGH/RIDGE COUPLETS) AND LACK OF ANY DOWNSTREAM NORTH ATLANTIC BLOCKING. THIS AGGRESSIVE FLOW WILL HELP KICK OUT CURRENT FOUR-CORNERS WAVE...WHICH WILL CUT ACROSS THE NORTHERN LAKES SUNDAY NIGHT INTO MONDAY...BRINGING A PLETHORA OF DIFFERENT WEATHER TYPES. PLENTY OF SUPPORT FOR A MUCH TAMER PERIOD OF WEATHER HEADING THROUGH THE MIDDLE OF NEXT WEEK AS AREA BECOMES CENTERED BETWEEN ACTIVE STORM TRACKS. FORECAST CONCERNS CONTINUE TO FOCUS ON WEATHER TYPES AND POTENTIAL IMPACTS FROM SUNDAY NIGHT AND MONDAYS SYSTEM. AGGRESSIVE PUSH OF WAA/ISENTROPIC UPGLIDE ON NOSE OF 50+ KNOT LOW LEVEL JET WILL RACE ACROSS THE AREA SUNDAY EVENING...ACCOMPANIED BY AN AREA OF MODERATE PRECIP. WAA NOT AS AGGRESSIVE AT THE SURFACE...ALTHOUGH STOUT OFF THE DECK WARM NOSE ENSURES ANYTHING REACHING THE SURFACE ACROSS NORTHERN LOWER WILL BE OFF THE LIQUID VARIETY. SOME LINGERING NEAR FREEZING AREAS/COLD SKIN TEMPERATURES MAY CONTINUE TO RESULT IN POCKETS OF FREEZING RAIN ACROSS THE INTERIOR HIGHLANDS DURING THE EARLY EVENING...WITH PLAIN RAIN FALLING ELSEWHERE. EVAP COOLING ALLOWS COLUMN TEMPERATURES TO STRADDLE THE FREEZING LINE NORTH OF THE BRIDGE...SUGGESTING PRIMARILY A SNOW OR SNOW/SLEET MIXTURE AS STEADIEST/HEAVIEST PRECIP ARRIVES. WHILE SNOW TO LIQUID RATIOS WILL REMAIN LOW...A SEVERAL HOUR PERIOD OF POTENTIALLY HEAVY SNOWFALL RATES WILL LIKELY PRODUCE A FEW INCHES (2 TO 5) ACROSS INTERIOR EASTERN UPPER. STRONG SHORTWAVE AND ATTENDANT SURFACE LOW PIVOT INTO CENTRAL UPPER MICHIGAN BY MONDAY MORNING...ALLOWING A PRETTY RESPECTABLE MID LEVEL DRY SLOT TO OVERSPREAD NORTHERN LOWER MICHIGAN. THIS SHOULD BRING MORE OF A VERY LIGHT RAIN/DRIZZLE SCENARIO OVERNIGHT. MOISTURE REMAINS DEEPER NORTH OF THE STRAITS ALONG AND NORTH OF SURFACE WARM FRONT. SNOW/SLEET MIXTURE SHOULD TRANSITION MORE TO A RAIN/SLEET/FREEZING RAIN/SNOW MIXTURE AS 900MB CENTERED WARM NOSE INCREASES TO +2C...WITH JUST MINIMAL ADDITIONAL SNOW ACCUMULATIONS AFTER MIDNIGHT. SYSTEM CONTINUES TO OCCLUDE/WEAKEN AS IT PUSHES OFF INTO CANADA LATER MONDAY AND MONDAY NIGHT. DRY SLOT FOLLOWS SUITE...WITH DEEPER MOISTURE ALONG SECONDARY TROUGH AXIS PUSHING INTO THE REGION THROUGH THE DAY. BACKSIDE CAA NOT NEARLY AS AGGRESSIVE...SUGGESTING A SLOWER TRANSITION BACK TO SNOW THAN WHAT IT APPEARED LIKE YESTERDAY. COLD LAYER DEEPENS ENOUGH TO SUPPORT PRIMARILY SNOW BY LATE AFTERNOON...WITH SOME MINOR (SUB ONE INCH) ACCUMULATIONS POSSIBLE...ESPECIALLY WHERE WEST FLOW UPSLOPE IS MAXIMIZED INTO THE HIGHLANDS. REAL MARGINAL CONDITIONS FOR NW-WNW LAKE ENHANCEMENT MONDAY NIGHT WITH DELTA T/S FLIRTING WITH 13C AND INVERSION LEVELS AT H85 LEVEL. PERHAPS AN ADDITIONAL INCH OF SNOW IN FAVORED AREAS...OTHERWISE JUST SOME SCATTERED LIGHT SNOW SHOWERS AND FLURRIES. OTHER THAN SOME LINGERING LIGHT SNOW SHOWERS TUESDAY MORNING...JUST NOT A WHOLE LOT TOO TALK ABOUT HEADING INTO THURSDAY AS NORTHERN LAKES BECOMES CENTERED BETWEEN NORTHERN AND SOUTHERN STREAM WAVES. IMAGINE A FEW FLURRIES/LIGHT SNOW SHOWERS ARE POSSIBLE LATER WEDNESDAY INTO WEDNESDAY NIGHT AS SOUTHERN PORTION OF NORTHERN WAVE SWEEPS ACROSS...BUT NOT WORTHY OF A SPECIFIC MENTION IN THIS FORECAST. POTENTIAL FOR A STRONGER HYBRID CLIPPER TYPE SYSTEM TO ARRIVE TO END THE EXTENDED...BRINGING ADDITIONAL LIGHT SNOW CHANCES. TEMPERATURES TO AVERAGE NEAR TO ABOVE NORMAL WEDNESDAY THROUGH FRIDAY...WITH A SHOT OF COOLER AIR ARRIVING TO START NEXT WEEKEND (SUBJECT TO MANY CHANGES...OF COURSE). && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1148 PM EST SAT FEB 9 2013 BRIEF PERIOD OF MVFR CEILINGS AT MBL THROUGH 08Z-09Z...OTHERWISE VFR UNTIL SUNDAY AFTERNOON AS CLOUDS LOWER AND PRECIPITATION MOVES IN FROM THE SOUTHWEST. COULD START AS A PERIOD OF FREEZING RAIN/SLEET MAINLY AT APN/PLN. && .MARINE... ISSUED AT 420 PM EST SAT FEB 9 2013 SOUTHERLY WINDS WILL INCREASE TONIGHT AND FURTHER THROUGH THE DAY SUNDAY IN ADVANCE OF ANOTHER LOW PRESSURE SYSTEM THAT WILL TRACK THROUGH THE NRN LAKES LATE SUNDAY INTO MONDAY. AT THIS POINT...WITH WARMING TEMPS OVER THE LAKES/INCREASING LAKE STABILITY...DON`T THINK WIND GUSTS WILL REACH GALE FORCE WITH THIS SYSTEM. HOWEVER...A HANDFUL OF SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SUNDAY AND SUNDAY NIGHT. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JA SYNOPSIS...NTS SHORT TERM...TBA LONG TERM...MSB MARINE...TBA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1150 PM EST SAT FEB 9 2013 .SYNOPSIS... ISSUED AT 420 PM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO ALL SNOW ON MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. MAINLY QUIET WEATHER WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK...WITH SEASONAL TEMPERATURES EXPECTED. && .UPDATE... ISSUED AT 742 PM EST SAT FEB 9 2013 MADE SOME EARLY TWEAKS TO FORECAST. COMBINATION OF SHALLOW LAKE CLOUDS OVER LAKE MICHIGAN AND PATCHY MID LEVEL AC WILL TEND TO KEEP EASTERN UPPER ON THE CLOUDY SIDE OVERNIGHT (ASSUMING LAKE MICHIGAN CLOUDS GET ADVECTED EASTWARD A BIT). AT THE SAME TIME... CURRENTLY NOT AS CONCERNED WITH LOW CLOUDS SPILLING INTO NORTHWEST LOWER WITH STRENGTHENING SOUTHEAST SURFACE FLOW OVER THE LOWER PENINSULA. BOTH RAP AND NAM-WRF HAVING BOUNDARY LAYER ISSUES...RAP FORECAST SOUNDINGS TOO COLD (SUGGESTING IT SHOULD ALREADY BE IN THE MID TEENS AT GLR/GOV/CAD WHEN IN REALITY TEMPERATURES ARE 8-10F WARMER)...AND NAM-WRF SOUNDINGS ARE TOO MOIST. THINK THERE WILL BE ENOUGH OF A GRADIENT TO KEEP THINGS FROM DE-COUPLING AND RADIATING LIKE MAD. SO HAVE NUDGED TEMPERATURE TRENDS UP A BIT (AND MINIMUM TEMPERATURES BY EXTENSION). && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 420 PM EST SAT FEB 9 2013 ELONGATED SFC RIDGE AXIS JUST OFF TO THE EAST OF THE STATE THIS AFTERNOON WITH SOUTHERLY RETURN FLOW STRENGTHENING ACROSS THE STATE. ABUNDANT SUN ACROSS NRN LOWER MICHIGAN TODAY. REMAINING LAKE CLOUDS OVER LAKE MICHIGAN STILL STILL JUST OFFSHORE OF LOWER MICHIGAN BUT SHOWING A LITTLE SIGN OF INCHING BACK TOWARD SHORE. UPPER MICHIGAN GETTING RIPPED OFF HOWEVER...AS SOUTHERLY MEAN LOW LEVEL WIND IS DRAGGING LAKE CLOUDS UP THROUGH A GOOD PART OF EASTERN UPPER. KERY REPORTED 5SM -SN ABOUT TWO HOURS AGO. SO...STILL GETTING SOME SHALLOW NUISANCE LAKE SNOWS. TONIGHT...MORE NUISANCE STUFF TO WORRY ABOUT THAN ANYTHING. LAKE CLOUDS OVER SRN LAKE MICHIGAN ARE STARTING TO ERODE FROM THE SOUTH AS WARMER LOW LEVEL AIR MAKES ITS WAY UP THE LAKE. HOWEVER...STILL A WINDOW OF OPPORTUNITY TO GET SOME LAKE CLOUDS INTO THE PARTS OF NW LOWER MICHIGAN THIS EVENING AS WE GET MORE OF A WESTERLY COMPONENT TO THE WIND...ALTHOUGH REMAINING LAKE CLOUDS SHOULD FURTHER ERODE AWAY FROM THE SOUTH AS WARMER LOW LEVEL AIR WORKS INTO REGION. SECOND PROBLEM IS STRATUS AND/OR FOG POTENTIAL. AS WE GET MORE OF A WESTERLY COMPONENT OFF LAKE MICHIGAN...FORECAST SOUNDINGS SHOW ADDITIONAL MOISTURE GETTING PULLED INTO NRN LOWER MICHIGAN THROUGH THE NIGHT (DEW POINT TRACE FOLDS OVER-TOP THE BOUNDARY LAYER). THIS SUGGESTS THE POSSIBILITY OF DEVELOPMENT OF LOW STRATUS AND/OR FOG AS WARM/MOIST LAYER ALOFT ADVECTS OVER A COLD BOUNDARY LAYER. DIDN`T GO MOSTLY CLOUDY...BUT DO HAVE AN INCREASE IN CLOUD COVER (PARTLY CLOUDY) THIS EVENING. TEMPS...YET ANOTHER ISSUE. HAVE MAINLY CLEAR SKIES INTERIOR GOING INTO THE EVENING WHICH WILL ALLOW TEMPS TO DROP QUICKLY AGAIN. BUT TEMP FREE-FALL WILL BE THROTTLED COMPARED TO LAST NIGHT BY STRONGER FLOW OFF THE SFC. DON`T FORESEE BELOW ZERO READINGS TONIGHT GIVEN THE STRONGER WINDS AND CLOUD POTENTIAL...BUT SOME OF THE COLDER SPOTS DIPPING INTO THE SINGLE DIGITS CERTAINLY NOT OUT OF THE QUESTION. SUNDAY...ANY CIGS/FOG WILL ERODE DURING THE MORNING HOURS AS WARMER AIR CONTINUES TO WORK INTO THE REGION. NEXT WEATHER MAKER WILL BE WORKING INTO THE MIDWEST THROUGH THE COURSE OF THE DAY. STRONG PULSE OF WARM ADVECTION EXPECTED TO PUSH PRECIP UP THROUGH THE STATE... GENERALLY BETWEEN THE 21Z AND 00Z TIME FRAME (MODEL CONSENSUS IS PRETTY CLOSE)...WHICH SEEMS REASONABLE GIVEN THE VERY DRY AIR IN PLACE DOWNSTAIRS INITIALLY. BUT ONCE AGAIN...WARM NOSE ALOFT ROCKETING INTO THE REGION WILL ALSO BRING ANOTHER ROUND OF P-TYPE ISSUES TO NORTHERN MICHIGAN. COLD TEMPS TO START AND SFC TEMPS JUST INCHING TO AROUND THE FREEZING MARK WILL PRESENT A RAIN/FREEZING RAIN PROBLEM OVER THE HIGH TERRAIN/NE LOWER MICHIGAN. SNOW/SLEET/ FREEZING RAIN MIX IN EASTERN UPPER WITH SLIGHTLY COLDER AIR ALOFT. DON`T THINK WE GET WARNING CRITERIA PRECIP OF ANY TYPE. BUT MAY ULTIMATELY NEED SOME ADVISORIES ISSUED...BUT WILL ALLOW LATER SHIFTS TO TAKE CARE OF THAT. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 420 PM EST SAT FEB 9 2013 PROGRESSIVE PATTERN SET TO CONTINUE...COURTESY OF ONE AGITATED PACIFIC PATTERN (WHICH WATER VAPOR IMAGERY SHOWS COVERED WITH A VIRTUAL WAVE-TRAIN OF STRONG TROUGH/RIDGE COUPLETS) AND LACK OF ANY DOWNSTREAM NORTH ATLANTIC BLOCKING. THIS AGGRESSIVE FLOW WILL HELP KICK OUT CURRENT FOUR-CORNERS WAVE...WHICH WILL CUT ACROSS THE NORTHERN LAKES SUNDAY NIGHT INTO MONDAY...BRINGING A PLETHORA OF DIFFERENT WEATHER TYPES. PLENTY OF SUPPORT FOR A MUCH TAMER PERIOD OF WEATHER HEADING THROUGH THE MIDDLE OF NEXT WEEK AS AREA BECOMES CENTERED BETWEEN ACTIVE STORM TRACKS. FORECAST CONCERNS CONTINUE TO FOCUS ON WEATHER TYPES AND POTENTIAL IMPACTS FROM SUNDAY NIGHT AND MONDAYS SYSTEM. AGGRESSIVE PUSH OF WAA/ISENTROPIC UPGLIDE ON NOSE OF 50+ KNOT LOW LEVEL JET WILL RACE ACROSS THE AREA SUNDAY EVENING...ACCOMPANIED BY AN AREA OF MODERATE PRECIP. WAA NOT AS AGGRESSIVE AT THE SURFACE...ALTHOUGH STOUT OFF THE DECK WARM NOSE ENSURES ANYTHING REACHING THE SURFACE ACROSS NORTHERN LOWER WILL BE OFF THE LIQUID VARIETY. SOME LINGERING NEAR FREEZING AREAS/COLD SKIN TEMPERATURES MAY CONTINUE TO RESULT IN POCKETS OF FREEZING RAIN ACROSS THE INTERIOR HIGHLANDS DURING THE EARLY EVENING...WITH PLAIN RAIN FALLING ELSEWHERE. EVAP COOLING ALLOWS COLUMN TEMPERATURES TO STRADDLE THE FREEZING LINE NORTH OF THE BRIDGE...SUGGESTING PRIMARILY A SNOW OR SNOW/SLEET MIXTURE AS STEADIEST/HEAVIEST PRECIP ARRIVES. WHILE SNOW TO LIQUID RATIOS WILL REMAIN LOW...A SEVERAL HOUR PERIOD OF POTENTIALLY HEAVY SNOWFALL RATES WILL LIKELY PRODUCE A FEW INCHES (2 TO 5) ACROSS INTERIOR EASTERN UPPER. STRONG SHORTWAVE AND ATTENDANT SURFACE LOW PIVOT INTO CENTRAL UPPER MICHIGAN BY MONDAY MORNING...ALLOWING A PRETTY RESPECTABLE MID LEVEL DRY SLOT TO OVERSPREAD NORTHERN LOWER MICHIGAN. THIS SHOULD BRING MORE OF A VERY LIGHT RAIN/DRIZZLE SCENARIO OVERNIGHT. MOISTURE REMAINS DEEPER NORTH OF THE STRAITS ALONG AND NORTH OF SURFACE WARM FRONT. SNOW/SLEET MIXTURE SHOULD TRANSITION MORE TO A RAIN/SLEET/FREEZING RAIN/SNOW MIXTURE AS 900MB CENTERED WARM NOSE INCREASES TO +2C...WITH JUST MINIMAL ADDITIONAL SNOW ACCUMULATIONS AFTER MIDNIGHT. SYSTEM CONTINUES TO OCCLUDE/WEAKEN AS IT PUSHES OFF INTO CANADA LATER MONDAY AND MONDAY NIGHT. DRY SLOT FOLLOWS SUITE...WITH DEEPER MOISTURE ALONG SECONDARY TROUGH AXIS PUSHING INTO THE REGION THROUGH THE DAY. BACKSIDE CAA NOT NEARLY AS AGGRESSIVE...SUGGESTING A SLOWER TRANSITION BACK TO SNOW THAN WHAT IT APPEARED LIKE YESTERDAY. COLD LAYER DEEPENS ENOUGH TO SUPPORT PRIMARILY SNOW BY LATE AFTERNOON...WITH SOME MINOR (SUB ONE INCH) ACCUMULATIONS POSSIBLE...ESPECIALLY WHERE WEST FLOW UPSLOPE IS MAXIMIZED INTO THE HIGHLANDS. REAL MARGINAL CONDITIONS FOR NW-WNW LAKE ENHANCEMENT MONDAY NIGHT WITH DELTA T/S FLIRTING WITH 13C AND INVERSION LEVELS AT H85 LEVEL. PERHAPS AN ADDITIONAL INCH OF SNOW IN FAVORED AREAS...OTHERWISE JUST SOME SCATTERED LIGHT SNOW SHOWERS AND FLURRIES. OTHER THAN SOME LINGERING LIGHT SNOW SHOWERS TUESDAY MORNING...JUST NOT A WHOLE LOT TOO TALK ABOUT HEADING INTO THURSDAY AS NORTHERN LAKES BECOMES CENTERED BETWEEN NORTHERN AND SOUTHERN STREAM WAVES. IMAGINE A FEW FLURRIES/LIGHT SNOW SHOWERS ARE POSSIBLE LATER WEDNESDAY INTO WEDNESDAY NIGHT AS SOUTHERN PORTION OF NORTHERN WAVE SWEEPS ACROSS...BUT NOT WORTHY OF A SPECIFIC MENTION IN THIS FORECAST. POTENTIAL FOR A STRONGER HYBRID CLIPPER TYPE SYSTEM TO ARRIVE TO END THE EXTENDED...BRINGING ADDITIONAL LIGHT SNOW CHANCES. TEMPERATURES TO AVERAGE NEAR TO ABOVE NORMAL WEDNESDAY THROUGH FRIDAY...WITH A SHOT OF COOLER AIR ARRIVING TO START NEXT WEEKEND (SUBJECT TO MANY CHANGES...OF COURSE). && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1148 PM EST SAT FEB 9 2013 BRIEF PERIOD OF MVFR CEILINGS AT MBL THROUGH 08Z-09Z...OTHERWISE VFR UNTIL SUNDAY AFTERNOON AS CLOUDS LOWER AND PRECIPITATION MOVES IN FROM THE SOUTHWEST. COULD START AS A PERIOD OF FREEZING RAIN/SLEET MAINLY AT APN/PLN. && .MARINE... ISSUED AT 420 PM EST SAT FEB 9 2013 SOUTHERLY WINDS WILL INCREASE TONIGHT AND FURTHER THROUGH THE DAY SUNDAY IN ADVANCE OF ANOTHER LOW PRESSURE SYSTEM THAT WILL TRACK THROUGH THE NRN LAKES LATE SUNDAY INTO MONDAY. AT THIS POINT...WITH WARMING TEMPS OVER THE LAKES/INCREASING LAKE STABILITY...DON`T THINK WIND GUSTS WILL REACH GALE FORCE WITH THIS SYSTEM. HOWEVER...A HANDFUL OF SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SUNDAY AND SUNDAY NIGHT. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...NTS SHORT TERM...TBA LONG TERM...MSB MARINE...TBA
AREA FORECAST DISCUSSION
NWS JACKSON MS
900 PM CST MON FEB 11 2013 .UPDATE...SUBTLE SHORTWAVE NOTED ON SATELLITE AND RUC ANALYSIS WAS NEARING OUR CWA THIS EVENING AND HAS HELPED SPREAD THE RAIN ACROSS OUR NORTHERN ZONES. HAVE INCREASED POPS THIS EVENING ACROSS OUR NORTH. A FEW STORMS WERE NOTED IN THE SOUTH AND THINKING IS THE ANY ELEVATED INSTABILITY WILL REMAIN SOUTH SO HAVE REMOVED THUNDER WORDING ALONG AND NORTH OF I-20. FLASH FLOOD WATCH WILL REMAIN IN EFFECT TONIGHT. FLOODING IS ON GOING ACROSS MUCH OF OUR SOUTH AND THE POTENTIAL FOR A TSTM WITH HEAVY RAINFALL WILL REMAIN TONIGHT. DEW POINTS WERE RUNNING A LITTLE DRY BUT TEMPERATURES WERE ON TRACK. UPDATED FCST HAS BEEN POSTED. /22/ && .AVIATION...RAIN WILL CONTINUE TO AFFECT THE WHOLE AREA TONIGHT. A FEW TSTMS WILL ALSO AFFECT HBG AND MEI AT TIMES. IN THE RAIN...MVFR CIGS WILL PREDOMINATE...WITH OCCASIONAL REDUCTIONS TO IFR CIGS/VSBYS WITH THE HEAVIER SHOWERS. TUESDAY...SHRA AND TSRA COVERAGE WILL INCREASE OVER THE ENTIRE AREA. SOME STORMS MAY CONTAIN HAIL TUESDAY. /DL/22/ && .PREV DISCUSSION... /ISSUED 430 PM CST MON FEB 11 2013/ ..STORMS AND ADDITIONAL HEAVY RAINFALL THROUGH TUESDAY... DISCUSSION...NUMEROUS TO WIDESPREAD SHOWERS HAVE BEEN OCCURRING THROUGH THE BULK OF THE DAY ACROSS CENTRAL AND SOUTHERN SECTIONS OF THE FORECAST AREA WHILE RAIN IN NORTHERN PORTIONS OF THE AREA HAS REMAINED RELATIVELY LIGHT. SINCE MIDDAY THUNDERSTORMS HAVE INCREASINGLY MIXED IN WITH THE SHOWERS SOUTH OF INTERSTATE TWENTY AS THE ATMOSPHERE UTILIZES ELEVATED INSTABILITY DEVELOPING NORTH OF THE STALLED FRONT ALONG THE GULF COAST. CURRENT ATMOSPHERIC LIFT IS MAINLY A RESULT OF ISENTROPIC LIFT AND FRONTAL CONVERGENCE FROM 3 TO 6 KFT ABOUT THE SURFACE. A MINOR WAVE IN PERTURBED AND FAST SOUTHWEST FLOW ALOFT HAS ALSO BEEN AIDING IN CONVECTIVE COVERAGE. HOWEVER...THIS WEAK WAVE WILL BE EXITING TO THE EAST SHORTLY...WHICH WILL LIKELY ALLOW SOME ACTIVITY TO BECOME CONCENTRATED A LITTLE FURTHER SOUTH IN THE REGION THROUGH THE EVENING. BUT ANY DECREASE IN OVERALL PRECIPITATION SHOULD NOT LAST VERY LONG SINCE A LARGER DISTURBANCE WILL BE APPROACHING BEFORE DAYBREAK TOMORROW. THE ABOVE-MENTIONED DISTURBANCE SHOULD BEGIN TO INCREASE SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE ENTIRE REGION LATE TONIGHT THROUGH TOMORROW MORNING. EXPECTED SHEAR AND ELEVATED INSTABILITY WILL PROBABLY RESULT IN SOME ORGANIZED STORMS CAPABLE OF PRODUCING HAIL. FORTUNATELY...THE ANTICIPATED LACK OF SURFACE INSTABILITY IN MOST AREAS (SINCE THE STALLED FRONTAL BOUNDARY WILL REMAIN TO THE SOUTH) SHOULD GREATLY LIMIT THE POTENTIAL FOR DAMAGING WIND GUSTS OR TORNADOES. BUT AN EXCEPTION TO THIS COULD DEVELOP BY AFTERNOON OVER SOUTHEASTERN MS (MAINLY SOUTH OF A BROOKHAVEN TO LAUREL LINE) AS TRANSIENT SURFACE CYCLOGENESIS TRIES TO BUCKLE THE STALLED SURFACE BOUNDARY AS FAR NORTH AS THE HIGHWAY 98 CORRIDOR. IF THIS OCCURS THEN STORMS IN FAR SE MS MIGHT HAVE BRIEF ACCESS TO AMPLE WIND SHEAR AND DECENT INSTABILITY OF A NON-ELEVATED NATURE...THUS INCREASING THE POTENTIAL FOR SUPERCELLS ROOTED IN THE BOUNDARY LAYER. FOR THAT REASON WE WILL BE MONITORING THE SITUATION IN SOUTHEASTERN MS CLOSELY TOMORROW...ESPECIALLY CONSIDERING CLEAN-UP EFFORTS FROM YESTERDAY`S TORNADOES ARE ONGOING. FOR THIS PACKAGE WE DECIDED TO EXPAND THE FLOOD WATCH PREVIOUSLY IN EFFECT FOR AREAS SOUTH OF I-20 TO COVER MOST OF THE REGION OUTSIDE OF SOME ARKLAMISS DELTA COUNTIES. EVEN THOUGH THE ADDED COUNTIES AND PARISHES ARE STILL GENERALLY NOT EXPECTED TO GET AS MUCH TOTAL RAIN AS THOSE LOCATIONS FURTHER SOUTH...THERE MIGHT BE ENOUGH TO PROMPT SOME FLASH FLOODING GIVEN THE VERY SATURATED STATE OF THE GROUND. FINALLY LOOKS AS IF NUMEROUS SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS WILL BE QUICKLY EXITING TO THE EAST LATE TOMORROW...BRINGING AN END TO THE HEAVY RAIN AND SEVERE WEATHER RISK. AT LEAST A FEW SHOWERS MAY CONTINUE LATE TOMORROW NIGHT INTO WEDNESDAY MORNING...ESPECIALLY IN NORTHERN AND EASTERN ZONES OF MS...BUT THIS ACTIVITY SHOULD REALLY POSE NO RISK OF ADDITIONAL HAZARDOUS WEATHER. /BB/ PREV DISCUSSION... /ISSUED 505 AM CST MON FEB 11 2013/ LONG TERM...FORTUNATELY THINGS WILL DRY OUT BY LATE WEDNESDAY AS A S/WV AND ASSOCIATED SURFACE LOW PASSING OVER THE REGION PUSH THE STALLED FRONT OUT INTO THE GULF AHEAD OF BUILDING SURFACE HIGH PRESSURE. CLEAR SKIES AND NEAR NORMAL TEMPERATURES WILL TAKE US THROUGH THE END OF THE WORK WEEK UNDER ZONAL FLOW ALOFT. NEXT RATHER WEAK CHANCE FOR ANY PRECIPITATION COMES LATE FRIDAY NIGHT AS A S/WV ROTATING THROUGH THE BASE OF THE LONGWAVE TROUGH OVER THE EASTERN HALF OF THE COUNTRY APPROACHES. RELATIVELY DRY CONDITIONS IN ADVANCE OF THE FRONT SHOULD PRECLUDE ANYTHING SIGNIFICANT...BUT STRONG FORCING ON THE NOSE OF A H7 JET STREAK MAY BE JUST ENOUGH FOR LIGHT PRECIP ACROSS THE DELTA LATE FRIDAY NIGHT. ITS VERY POSSIBLE TEMPS WILL BE COLD ENOUGH TO SUPPORT SNOW FLURRIES AS THIS ACTIVITY PASSES...BUT AGAIN...ANYTHING THAT DEVELOPS WILL BE VERY LIGHT. CHILLY HIGH PRESSURE TRANSITS THE REGION OVER THE WEEKEND BRINGING MORE DRY WEATHER AND BELOW NORMAL TEMPS...BEFORE SOUTHERLY FLOW AND A WARMING TREND RETURNS EARLY NEXT WEEK AS THE SURFACE HIGH SLIDES OFF TO OUR EAST. /BK/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 49 57 49 54 / 84 100 16 14 MERIDIAN 49 59 50 58 / 90 99 36 19 VICKSBURG 49 56 45 54 / 75 100 15 12 HATTIESBURG 52 67 56 61 / 100 93 38 25 NATCHEZ 51 59 48 54 / 100 100 12 11 GREENVILLE 45 52 42 53 / 55 90 33 13 GREENWOOD 48 53 44 52 / 55 97 36 14 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...FLASH FLOOD WATCH FROM 6 AM CST TUESDAY THROUGH TUESDAY AFTERNOON FOR MSZ025>033-035>042. FLASH FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR MSZ043>066- 072>074. LA...FLASH FLOOD WATCH FROM 6 AM CST TUESDAY THROUGH TUESDAY AFTERNOON FOR LAZ008-009-015. FLASH FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR LAZ016-023>026. AR...NONE. && $$ 22/BB/BK
AREA FORECAST DISCUSSION
NWS BILLINGS MT
402 AM MST SUN FEB 10 2013 .SHORT TERM...VALID FOR TDY AND MON... WITH THIS FORECAST PACKAGE...HAVE UPGRADED THE RED LODGE AND BEARTOOTH FOOTHILLS TO A WINTER STORM WARNING AND CONTINUED THE WINTER WEATHER ADVISORY FOR THE BIG HORN MOUNTAINS...SOUTHERN BIG HORN COUNTY AND SHERIDAN COUNTY WYOMING. VAD WINDS CONTINUE TO SHOW DEEP NORTHERLY FLOW UP ABOUT TO 10K FEET AGL WITH MODELS SHOWING PLENTY OF MOISTURE AVAILABLE AND UNSTABLE LAPSE RATES. THUS THE RED LODGE AND BEARTOOTH FOOTHILLS ZONES CONTINUE TO SEE EXCELLENT UPSLOPE SNOW THIS MORNING. REPORTS FROM AROUND MIDNIGHT SHOWED UP TO 5 INCHES OF SNOW HAD ALREADY FALLEN. HOWEVER..SINCE MIDNIGHT...RADAR AND WEBCAMS CONTINUE TO SHOW MODERATE TO HEAVY SNOW FALLING. BOTH THE RAP AND NAM ARE LOCKED IN ON SETTLING A BAND OF UPSLOPE SNOW AGAINST THE FOOTHILLS THROUGH THE MORNING. THIS AFTERNOON...THE UPSLOPE FLOW WILL DIMINISH ALONG WITH SHALLOWING MOISTURE...CAUSING THE SNOW TO TAPER OFF GOING INTO THIS EVENING. EXPECT TO SEE REPORTS OF 6 TO 10 INCHES OF SNOW WITH LOCALLY HIGHER AMOUNTS IN THIS AREA. RADAR ALSO CONTINUES TO SHOW ENHANCED SNOWFALL ALONG THE BIG HORN AND PRYOR MOUNTAIN FOOTHILLS AS WELL AS OVER THE BIG HORN MOUNTAINS. SHERIDAN HAS LARGELY BEEN SHADOWED BY THE DOWNSLOPE NORTHWEST WINDS OVERNIGHT...HOWEVER...ANTICIPATE SNOW TO INCREASE THIS MORNING AS THE FRONTAL BOUNDARY SETTLES IN AGAINST THE MOUNTAINS. AREAS FROM BILLINGS TO HARLOWTON TO ROUNDUP WILL CONTINUE TO SEE SOME SCATTERED SNOW SHOWERS THIS MORNING IN CONVECTIVE SNOW BANDS. HOWEVER...WITH THE STIFF NORTHERLY WINDS...THESE AREAS WILL LARGELY NOT SEE MUCH MORE SNOW ACCUMULATION AS RADAR CLEARLY SHOWS THE DOWNSLOPING IS IN IN FULL EFFECT. ALL OF THIS SNOWFALL HAS BEEN THE RESULT OF THE SHORTWAVE TROUGH APPROACHING FROM THE NORTH. THE SHORTWAVE IS CURRENTLY SEEN ON WV IMAGERY ENTERING NORTHERN MONTANA. THIS WAVE WILL SLOWLY TRACK SOUTH ACROSS THE FORECAST AREA THROUGH THIS AFTERNOON. THE WAVE WILL BE OVER THE FORECAST AREA BY THIS AFTERNOON...WHICH WILL RESULT IN THE BEST FORCING SHIFTING SOUTH OF THE FORECAST AREA...ALONG WITH THE NORTHERLY WINDS WEAKENING AND STARTING TO TURN TO THE WEST. GIVEN THE INSTABILITY UNDER THE WAVE AXIS...EXPECT SOME SCATTERED SNOW SHOWERS TO CONTINUE ACROSS EASTERN MONTANA...ALTHOUGH ACCUMULATIONS WILL LIKELY BE VERY LIGHT. ALL PRECIPITATION WILL END ACROSS THE FORECAST AREA SUNDAY NIGHT INTO MONDAY MORNING AS SHORTWAVE RIDGING BUILDS IN BEHIND THE WAVE. SKIES WILL CLEAR OUT DURING THE DAY MONDAY...WITH WINDS SWITCHING AROUND TO THE WEST AS PREVIOUSLY MENTIONED. THIS WILL RESULT IN THE RETURN TO DOWNSLOPE FLOW ACROSS THE WESTERN AND CENTRAL ZONES...ALLOWING US TO START THE START THE WARMING TREND. THE PRESSURE GRADIENT LOOKS FAVORABLE FOR A CLARKS FOR DRAINAGE FLOW FOR BILLINGS...RESULTING IN TEMPERATURES RUNNING IN THE LOW 30S AS COMPARED TO UPPER 30S IN SURROUNDING AREAS. THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN ACROSS WESTERN ZONES GOING INTO MONDAY NIGHT...WHICH WILL RESULT IN A WINDY PERIOD FOR THE FOOTHILLS FROM LIVINGSTON TO NYE. CHURCH .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT AND ONLY MINOR ADJUSTMENTS MADE TO THE EXTENDED FORECAST. FAST NORTHWESTER FLOW OF AIR ALOFT WILL BE OVER THE REGION TUESDAY AND WEDNESDAY. SEVERAL SHORT WAVES MOVING THROUGH THIS FLOW WILL ALLOW A LEE SIDE SURFACE TROUGH TO DEVELOP AND BRING GAP FLOW WINDS TO THE SOUTHWEST VALLEYS. FLOW BECOMING NORTHERLY LATE ON WEDNESDAY AS A STRONG JET AND SHORT WAVE ENERGY CARVE OUT A TROUGH OF LOW PRESSURE OVER THE REGION. THIS WILL DRIVE A COLD FRONT INTO OUR AREA WEDNESDAY AFTERNOON WITH STRONG COLD AIR ADVECTION TO TAKE PLACE. SHOULD SEE A MIXTURE OF RAIN AND SNOW DURING THE AFTERNOON...CHANGING TO ALL SNOW OVERNIGHT. STEEP LAPSE RATES WILL BE OVER THE AREA FOR CONVECTIVE SNOW SHOWERS BUT PRECIPITATION WILL BE HAMPERED BY NORTHWEST DOWN SLOPE WINDS OVER THE PLAINS. THIS WILL LIMIT PRECIPITATION AMOUNTS FOR MOST AREAS. NORTHWEST WINDS WILL UPSLOPE INTO SOUTHERN BIG HORN AND NORTHERN WYOMING AND THESE AREAS COULD SEE ACCUMULATING SNOW BY THURSDAY MORNING. BELOW SEASONAL TEMPERATURES ARE EXPECTED THURSDAY AND FRIDAY BUT WILL WARM TO SEASONAL VALUES OVER THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDS IN OVER THE FORECAST AREA. RICHMOND && .AVIATION... AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE FORECAST AREA TODAY. PERIODS OF SNOW WILL MOVE FROM NORTHWEST TO SOUTHEAST AND WILL AFFECT ALL FLIGHT TERMINALS. MVFR TO LIFR CONDITIONS WILL BE LIKELY DUE TO LOW CEILINGS AND POOR VISIBILITY. NORTHWEST WINDS WILL BE INCREASING EAST OF A LINE FROM KSHR TO KMLS TODAY AND WILL CREATE AREAS OF BLOWING SNOW. THE SNOW WILL BRING MOUNTAIN OBSCURATIONS. SNOW WILL BE DECREASING FROM WEST TO EAST THIS AFTERNOON. RICHMOND && .PRELIMINARY POINT TEMP/POPS... TDY MON TUE WED THU FRI SAT ------------------------------------------------------- BIL 030 013/033 022/040 028/045 025/034 018/037 021/045 3/S 20/U 01/B 14/R 22/S 22/S 10/B LVM 028 010/034 026/036 029/042 023/032 016/034 018/040 5/S 30/N 01/N 14/O 32/S 21/B 11/B HDN 030 009/033 018/039 024/044 021/033 014/035 018/043 7/S 30/U 01/B 14/O 33/S 21/B 10/B MLS 029 012/032 023/039 026/042 024/031 014/032 016/041 6/S 31/B 01/B 14/O 32/S 21/B 10/B 4BQ 029 011/030 017/037 025/042 022/031 011/031 016/040 7/S 51/B 01/B 13/O 33/S 22/S 10/B BHK 027 010/026 019/035 023/038 020/027 009/027 013/037 7/S 51/B 01/B 03/S 33/S 22/S 10/B SHR 027 006/028 012/037 020/041 017/029 012/031 016/041 9/S 40/U 01/B 14/O 33/S 32/S 10/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 8 PM MST THIS EVENING FOR ZONE 38. WINTER STORM WARNING IN EFFECT UNTIL 8 PM MST THIS EVENING FOR ZONES 56-66. WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 8 PM MST THIS EVENING FOR ZONES 98-99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
259 PM CST SUN FEB 10 2013 .SHORT TERM...TODAY THROUGH MONDAY NIGHT. MAIN CONCERN DURING THIS TIME PERIOD WILL BE THE WINDS BEHIND THE SURFACE LOW. OUR NORTHERN COUNTIES...WHERE SNOWFALL OCCURRED EARLIER TODAY...WILL LIKELY RUN INTO VISIBILITY RESTRICTIONS AS BLOWING SNOW OCCURS THROUGH THE EARLY EVENING HOURS. ORD HAS EXPERIENCED VISIBILITIES BETWEEN ONE AND TWO MILES SINCE ABOUT 18Z TODAY...BUT EARLIER TODAY CONDITIONS WERE BELOW HALF A MILE. ALSO...THERE WILL BE A SLIGHT CHANCE FOR SNOW THROUGH THE REMAINDER OF TODAY...MAINLY FOR OUR NORTHERN COUNTIES. AT 20Z...THE RAP INDICATED A 500MB LOW APPROXIMATELY CENTERED OVER SIOUX FALLS SOUTH DAKOTA. THE SURFACE LOW WAS DIRECTLY UNDER THE UPPER LEVEL LOW...RESULTING IN A STACKED TROUGH WHICH IS NOW EXITING THE CENTRAL PLAINS. BEHIND THE SURFACE LOW...HEIGHT RISES ARE RESULTING IN A SHARP PRESSURE GRADIENT OVER THE OUTLOOK AREA. NORTHWESTERLY WIND SPEEDS OF 30 MPH WERE EXPERIENCED OVER NEARLY THE ENTIRE CWA. GUSTS WERE REACHING THE MID TO UPPER 40S...WITH ONLY A COUPLE SITES REACHING 50 MPH. THE WINTER WEATHER ADVISORY FOR BLOWING SNOW WILL CONTINUE UNTIL 9 PM TONIGHT TONIGHT. THIS WILL LIKELY NEED TO BE CONVERTED TO A WIND ADVISORY IF VISIBILITIES RECOVERY LATER TODAY. THE WIND ADVISORY COUNTIES UNTIL 9 PM...AS MODELS ARE NOT DEPICTING ANY LETTING UP OF THE PRESSURE GRADIENT BEFORE THEN. THE WIND ADVISORY MAY NEED TO BE EXTENDED FOR OUR EASTERN COUNTIES IF CONDITIONS DO NO EASE UP LATER TONIGHT. WIND SPEEDS WILL BEGIN TO RELAX AFTER MIDNIGHT AS THE PRESSURE GRADIENT EASES OVER THE REGION. A NORTHWESTERLY WIND COMPONENT WILL BE REALIZED OVER THE ENTIRE SHORT TERM PERIOD. HIGH TEMPERATURES FOR TOMORROW WILL BE RELATIVELY CLOSE TO NORMAL FOR THIS TIME OF YEAR. ON THE OTHER HAND...LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY...WEAK ZONAL FLOW IS EXPECTED ACROSS THE REGION TO BEGIN THE EXTENDED PERIODS AS THE VIGOROUS UPPER LEVEL LOW THAT MOVED ACROSS THE LOCAL AREA THIS MORNING APPROACHES THE EASTERN SEABOARD AND A SECOND UPPER LEVEL LOW TRACKS ACROSS THE DESERT SOUTHWEST. AT THE SAME TIME A WEAK UPPER LEVEL SHORTWAVE IS EXPECTED TO EXTEND ACROSS THE LOCAL AREA FROM THE NORTH...PROVIDING AMPLE MID LEVEL CLOUD COVER DURING THE OVERNIGHT HOURS MONDAY INTO TUESDAY MORNING...BUT WITH MINIMAL FORCING AND VERY LIMITED LOW LEVEL MOISTURE...DO NO EXPECT ANY SORT OF PRECIPITATION UNDER THIS SCENARIO. AS THE AFOREMENTIONED UPPER LEVEL ACROSS THE DESERT SOUTHWEST MOVES INTO THE SOUTHERN PLAINS TUESDAY AFTERNOON...THE UPPER LEVEL FLOW PATTERN WILL BECOME MORE AMPLIFIED...AS A RIDGE OF HIGH PRESSURE WORKS ITS WAY TOWARDS THE WEST COAST. THIS WILL ESTABLISH A NORTHWESTERLY FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS BY WEDNESDAY...WITH MULTIPLE QUICK PASSING UPPER LEVEL DISTURBANCES EXPECTED TO TRAVERSE THE PLAINS. WITH THE QUICK MOVING NATURE OF THESE DISTURBANCES AND DRY LOW LEVELS OF THE ATMOSPHERE...DO NOT THINK MORE THAN FLURRIES WILL BE REALIZED THROUGH THE END OF THE WEEK...WITH THE BEST GUEST AT TIMING BEING DURING THE DAY ACROSS THE NORTHWEST THURSDAY...AND ACROSS ALL AREAS ON FRIDAY. THE FIRST OF THESE DISTURBANCE WILL BE ACCOMPANIED BY A SURFACE COLD FRONT...WHICH IS EXPECTED TO KNOCK TEMPERATURES DOWN 10+ DEGREES F ON THURSDAY...WITH THIS COOLER...YET SEASONAL AIRMASS THEN EXPECTED TO PERSIST ACROSS THE LOCAL ARE THROUGH THE END OF THE WEEK. AHEAD OF THE FRONT...WEDNESDAY AFTERNOON APPEARS TO BE THE NICEST DAY OF THE WEEK...WITH A LIGHT DOWNSLOPING COMPONENT TO THE WINDS LIKELY HELPING TEMPERATURES CLIMB TO NEAR 50 DEGREES. && .PREV DISCUSSION... /ISSUED 1149 AM CST SUN FEB 10 2013/ AVIATION...18Z TAF FOR KGRI. LOW PRESSURE AT THE SURFACE WILL CONTINUE TO TRACK NORTHEAST THROUGH THE CENTRAL PLAINS REGION TODAY...AND MVFR CONDITIONS WILL PREVAIL THROUGH THE DAY UNTIL CEILINGS BEGIN TO RISE AROUND MIDNIGHT. WIND SPEEDS WILL BE ANOTHER ISSUE TODAY AS NORTHWESTERLY SPEEDS AROUND 30 KNOTS WILL BE REALIZED THROUGH THE EVENING. GUSTS WILL BE CLOSER TO 40 KNOTS THROUGH THE AFTERNOON AS PRESSURE RISES CONTINUE BEHIND THE SURFACE LOW...RESULTING IN A STRONG PRESSURE GRADIENT ACROSS SOUTH CENTRAL NEBRASKA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ041-047>049- 060>064-072>077-082>087. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ039- 040-046. KS...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ005>007-017>019. && $$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1233 PM EST SUN FEB 10 2013 .SYNOPSIS... A FRONT WILL BRING A LIGHT WINTRY MIX, INCLUDING FREEZING RAIN LATE TONIGHT INTO MONDAY MORNING, WITH A TRANSITION TO PLAIN RAIN MONDAY. MONDAY NIGHT, A COLD FRONT WILL BRING COLDER TEMPERATURES AND SNOW SHOWERS. SCATTERED SNOW SHOWERS AND FLURRIES WILL CONTINUE TUESDAY DOWNWIND OF LAKE ONTARIO AND LAKE ERIE. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 9 AM UPDATE... EXTENDED THE CLOUDS AND FLURRIES FOR A FEW MORE HOURS. SATELLITE SHOWING A SHRINKAGE IN COVERAGE. BY NOON THESE LOW CLOUDS WILL BE GONE BUT HIGH CLOUDS ALREADY SPREADING IN FROM THE SW AHEAD OF THE NEXT SYSTEM. ADJUSTED HOURLY TEMPERATURES. UNTIL SOME MIXING HAPPENS THE CLOUDS WILL REMAIN HOLDING TEMPERATURES STEADY THERE. OUTSIDE THE CLOUD AREAS TEMPERATURES RISING SLOWLY BUT HAVE A LONG WAY TO GO STARTING BELOW ZERO. 400 AM UPDATE...MADE MINOR TWEAKS MAINLY TO CLD COVER AND TEMPS ERLY THIS MORNING AS LOW CLDS STUBBORNLY HANG ON DOWNWIND OF LAKE ONTARIO. I SUSPECT THESE CLDS WILL DISSIPATE AFTER SUNRISE. ALSO HAVE A FEW FLURRIES FROM THESE CLOUDS AS SURFACE TEMPS ARE CLOSE TO THE MAX ICE CRYSTAL GROWTH RATE...SUGGESTING ANY OROGRAPHIC LIFTING CAN EASILY SQUEEZE OUT A FLURRY OR TWO. PREVIOUS DISCUSSION BELOW FROM 1 AM UPDATE... IR IMAGERY AND GOES 11-3.9 MICRON IMAGERY SHOWS PESKY LOW LAKE EFFECT CLOUDS HANGING ON UNDER A SHARP VERY LOW-LEVEL INVERSION WITHIN A SHALLOW NORTHWEST FLOW IN EC NY. KBGM 88D VWP SHOWS A 340-350 DEGREE WIND AT 10 KTS ABT 500 FEET AGL AND ALMOST LIGHT AND VARIABLE ABOVE THIS. THIS LOW CLOUD LAYER THAT WAS MAINLY DOWNWIND OF THE FINGER LAKES AND LAKE ONTARIO WAS SHRINKING AND WILL CONTINUE TO DO SO AS THE LATEST RAP 925 MB LAYER WINDS BETWEEEN 6 AND 9Z TURN MORE NORTH TO NORTHEAST AND WEAKEN...LOSING THE OVERLAKE TRAJECTORIES. IN ADDITION OUR LOCAL WRF MODEL WITH ITS HOURLY OUTPUT ALSO IS VERY SIMILAR AND DIMINISHES THE LOW CLD COVER IN A SIMILAR FASHION AS PER THE DRYING OF THE 925 MB LAYER AS THE 925 MB WINDS SHIFT MORE NRLY AND LOSE LAKE TRAJECTORIES. HENCE HAVE CLOUDS DIMINISHING FOR THE REMAINDER OF THE EARLY MORNING HOURS. MINS WILL BE TRICKY GIVING THE WIDE RANGE OF TEMPERATURES OBSERVED AT PRESENT DUE TO CLD CVR. IN CLD CVR AREAS TEMPS ARE IN THE TEENS WITH TEMPERATURES RAPIDLY DROPPING TO NEAR ZERO IN CLR SKY AREAS. I HAVE MINS RANGING FROM SUB ZERO SINGLE DIGITS MAINLY TO SINGLE DIGITS WHERE CLD CLEAR LATEST IN EC NY. FOR SUNDAY...SFC HIGH PRESSURE RDG AXIS IS OVHD AT 12Z AND RAPIDLY SHIFTS EAST DURING THE DAY...REACHING OFFSHORE BY EVENING. MEANWHILE NEXT STORM WAS BEGINNING TO WORK EASTWARD. THE 850 AND 925 MB WAA BEGINS DURING THE DAY AS SOUTHERLY WINDS INCREASE...THIS WILL ALSO POP UP AN UPPER LEVEL RDG OVHD DURING THE DAY SUNDAY. SOME HIGHER CLDS WILL ADVECT IN OVER THE UPR RDG... BUT THE DEEPER MID LAYER CLDS HOLD OFF MOST OF THE DAY REACHING WRN NY LATE. I SEE MAINLY CIRRUS OVERSPREADING C NY AND NE PA DURING AFTERNOON WITH A MILDER DAY IN STORE DUE TO LL WARM ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... ALL 00Z MODELS...INCLUDING THE NAM12...GFS40...CMC AND EURO ALL TRACK THE NEXT SIGNIFICANT CYCLONE TRACKING INTO WI BY 6Z MONDAY. AT UPPER LEVELS THERE WAS A LOW OVER THE WESTERN LAKES REGION WITH A PERSISTENT UPPER LVL RDG OFF THE SE COAST TO THE WRN GULF COAST. AS A RESULT OF THIS UPPER LEVEL GEOPOTENTIAL FIELD...THERE WAS A STRONG UPPER LEVEL JET STREAK THAT WILL PUNCH INTO THE OHIO VALLEY BETWEEN 6Z AND 18Z MONDAY. THIS WILL INDUCED A STRONG SOUTHERLY LOW-LEVEL JET ARND 850 MB UP INTO NY AND PA TONIGHT/ERLY MON. THIS LLJ WILL FEATURE STRONG MOISTURE ADVECTION AND RISE ISENTROPICALLY. ALL MODELS AGREE THAT PRECIP SPREADS FROM WEST TO EAST ACROSS CENTRAL NY AND NE PA BTWN 6Z AND 12Z MONDAY. WILL RAMP POPS UP TO CATEGORICAL BY 12Z ALL FORECAST AREA. NOW TO P-TYPE. INITIALLY TEMPERATURES AND DEWPOINTS MOST OF CWA WILL BE BELOW FREEZING WITH SUB FREEZING DWPTS AS WELL LATE TONIGHT. MODEL GUIDC SUGGESTS OUR DOWNSLOPE REGIONS IN THE NRN FINGER LAKES ACTUALLY REMAIN ABV FREEZING WHICH IS NOT UNUSUAL TONIGHT. SO I WUD EXPECT STEADY AND SLOWING RISING TEMPERATURES SUNDAY NIGHT REST OF ZFORECAST AREA. WHEN PRECIP ARRIVES IT WILL BE MAINLY ZR INITIALLY WITH POSSIBLY SOME IP...BUT WITH 850 MB TEMPS ABV FREEZING DON/T SEE SNOW. PRECIPITATION WILL RAPIDLY TURN OVER TO PLAIN RAIN MONDAY DURING THE MORNING MOST OF CWA AS TEMPS WARM ABV FREEZING. THE LAST HOLD OUTS WILL BE IN THE FAR EASTERN PART OF THE CWA FROM SULLIVAN CO TO THE UPPER MOHAWK VALLEY WHERE ZR WILL LAST UNTIL AFTERNOON. ICE AMNTS WILL BE LIGHT...GENERALLY UNDER .1 INCHES...HOWEVER I SEE SOME AREAS IN THE CATSKILLS TO MOHAWK VALLEY SEEING MAYBE UP TO .15 INCH. MAIN IMPACT WILL BE TO TRAVEL. FOR NOW HELD OFF ON ISSUING ANY FLAGS FOR FREEZING RAIN AS NOT SURE AS TO THE EXTENT OR AREAL COVERAGE OF THE ICING. THERE IS PLENTY OF TIME AT THIS POINT IN OUR FORECAST AREA SO WILL LET DAY SHIFT HANDLE. I SUSPECT AN ADVY WILL BE ISSUED FOR A LARGE PART OF THE FORECAST AREA THIS AFTERNOON FOR LATE TONIGHT/MONDAY MORNING. THEN BY AFTERNOON MONDAY...RAIN SHIELD ASSOCIATED WITH WARM/MOIST CONVEYOR BELT IS EAST OF REGION AND THE COLD FRONT WILL SWING THRU BETWEEN 21Z MON AND 02Z TUE. THIS FEATURE WILL BE ACCOMPANIED BY CAA AND MAINLY SNOW SHOWERS WHICH WILL MIX WITH RAIN SHOWERS INITIALLY. FOR MONDAY NIGHT INTO EARLY TUESDAY...THE LL FLOW IS MORE W-SW WHICH SHUD DIRECTLY ANY LAKE MOISTURE AND DEVELOPING LES MAINLY N OF THE BGM FORECAST AREA. H85 TEMPS AT THIS POINT WILL BE MARGINAL AT BEST SO DOESN/T LOOK LIKE MUCH BEFORE TUE AM IN C NY OR NE PA OTHER THAN A FEW SNOW SHOWERS OR FLURRIES. THEN TUE INTO TUE NGT...ANOTHER WAVE AND ASSOCIATED COLD FRONT AND SURGE OF COLDER AIR PRESSES SOUTH TWD NY AND TURNS THE LL FLOW MORE W-NW WHICH COMBINED WITH H85 TEMPS DROPPING TO -12C SHUD TRIGGER SOME LAKE RESPONSE. FOR NOW HAVE POPS IN FOR LES NC NY LATER TUE INTO TUE NGT. THE NAM HOLDS ONTO THE LES LONGER THRU TUE NGT...GFS BACKS FLOW QUICKER TUE NGT. NOT SURE EXACTLY ON TIMING THIS FAR OUT SO PRETTY MUCH WENT WITH SCENARIO THAT KEEPS THE LES IN LONGER NC NY. NOT LOOKING FOR A MAJOR EVENT. GFS AND NAM SOUNDINGS FOR SYR SHOW INVERSION BARELY AT 850 MB AND MAX LIFT BELOW THE MAX GROWTH RATE FOR ICE CRYSTALS. I CUD SEE A FEW INCHES BUT NO WARNING AMNTS FOR LAKE SNOW BELTS IN NC NY...SO NO LES WATCH. REST OF FORECAST AREA WILL SEE TYPICAL BKN SC LAYER WITH SCATTERED FLURRIES OR EVEN SNOW SHOWERS WITH THE DAY/S HEATING. NO ACCUMS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 1230 PM UPDATE... THE LONG TERM PERIOD BEGINS WITH A SPLIT FLOW PATTERN...BUT A TRANSITION TO A MORE AMPLIFIED NORTHERN-STREAM-DOMINANT PATTERN WILL OCCUR AS WE HEAD INTO NEXT WEEKEND. TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATOLOGY AT THE START OF THE PERIOD...WILL GRADUALLY TREND BACK TO COLDER WITH TIME. GFS AND ECMWF DO NOT QUITE AGREE ON DETAILS OF HOW QUICKLY OR EVENTFULLY THAT PROCESS OCCURS. A COLD FRONT OF UNCERTAIN STRENGTH IS EXPECTED TO PASS SOMETIME AROUND EARLY FRIDAY TO INTRODUCE INITIAL COLDER AIR...WHICH FOR THE GFS MARKS AN AGGRESSIVE INVASION OF ARCTIC AIR FOR THE WEEKEND. THE ECMWF MEANWHILE GETS THE ARCTIC IN AS WELL...EVENTUALLY...BUT IN PIECES BECAUSE IT TAKES LONGER TO BREAK DOWN THE SOUTHWEST FLOW AHEAD OF THE AMPLIFIED INCOMING TROUGH /SO IT MAY TAKE UNTIL AFTER THE WEEKEND FOR THE COLDEST TEMPERATURES/. IN THE GRIDS...FOR NOW I TRIED TO STRIKE A BALANCE BY ALLOWING FOR TRENDING BELOW CLIMATOLOGY NEXT WEEKEND...BUT NOT AS ABRUPTLY AS THE 12Z GFS RUN. I ALSO ACCEPTED HPC POPS GENERALLY IN THE 30-50 PCT CHANCE RANGE FRIDAY NIGHT THROUGH SUNDAY...HIGHEST IN CENTRAL NY DOWNWIND OF LAKES ERIE/ONTARIO...SINCE THERE SHOULD BE SOME ABILITY FOR LAKE RESPONSES AS THE COLD AIR MAKES ITS WAY IN. BEFORE ALL THAT ARRIVES...I ONLY HAVE SLIGHT TO LOW CHANCE POPS AT BEST FROM THE WEAK WAVES OCCASIONALLY SKIMMING THROUGH OUR PERIPHERY WITHIN THE SPLIT FLOW. && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... 18Z UPDATE... HIGH PRESSURE IN CONTROL...KEEPING THINGS VFR THIS AFTERNOON THROUGH EVENING. HOWEVER...LATE TONIGHT THE HIGH PRESSURE WILL YIELD TO A QUICK MOVING SYSTEM WHICH WILL BRING MVFR CONDITIONS FROM A DASH OF WINTRY MIX /INCLUDING FREEZING RAIN/...SPREADING IN ROUGHLY WSW TO ENE DURING THE 09Z-14Z MONDAY TIME PERIOD. THE WINTRY MIX WILL CHANGE TO PLAIN RAIN FAIRLY QUICKLY...AND BECOME SCATTERED RAIN SHOWERS...BUT MVFR CIGS SHOULD REMAIN. FUEL ALTERNATE THRESHOLD IS EXPECTED TO BE REACHED FOR ALL TERMINALS EXCEPT KSYR-KRME MONDAY MORNING...AND SOME IFR CIGS POSSIBLE AT TIMES KBGM-KAVP. ALSO...WHILE NOT INDICATED YET IN TAFS AS POTENTIAL IS STILL BEING ASSESSED...LOW LEVEL WIND SHEAR IS NOT OUT OF THE QUESTION AS THE WAVE OF WINTRY MIX/RAIN MOVES THROUGH. SSW WINDS AT ABOUT THE 2 KFT AGL LEVEL WILL BE REACHING AROUND 50 KTS...BUT WITH CLOUDS AND OVERRUNNING WARM AIR IT MAY BE A GRADUAL STEPWISE INCREASE FROM THE SURFACE TO THAT LEVEL RATHER THAN AN ABRUPT ONE. IF LIKELIHOOD OF LLWS THRESHOLD INCREASES...IT MAY BE ADDED TO SOME TAFS. .OUTLOOK... MON AFT...MVFR CIGS/VIS IN SCT -SHRA. MON NGT/TUE/TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED/THU...VFR MOST OF THE TIME...BUT MVFR CIGS AND -SN POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MDP/TAC NEAR TERM...DJN/TAC SHORT TERM...DJN LONG TERM...MDP AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
925 AM EST SUN FEB 10 2013 .SYNOPSIS... A FRONT WILL BRING A LIGHT WINTRY MIX, INCLUDING FREEZING RAIN LATE TONIGHT INTO MONDAY MORNING, WITH A TRANSITION TO PLAIN RAIN MONDAY. MONDAY NIGHT, A COLD FRONT WILL BRING COLDER TEMPERATURES AND SNOW SHOWERS. THE SNOW SHOWERS AND FLURRIES WILL BE DOWNWIND OF LAKE ONTARIO AND LAKE ERIE, AND LAST UNTIL WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 9 AM UPDATE... EXTENDED THE CLOUDS AND FLURRIES FOR A FEW MORE HOURS. SATELLITE SHOWING A SHRINKAGE IN COVERAGE. BY NOON THESE LOW CLOUDS WILL BE GONE BUT HIGH CLOUDS ALREADY SPREADING IN FROM THE SW AHEAD OF THE NEXT SYSTEM. ADJUSTED HOURLY TEMPERATURES. UNTIL SOME MIXING HAPPENS THE CLOUDS WILL REMAIN HOLDING TEMPERATURES STEADY THERE. OUTSIDE THE CLOUD AREAS TEMPERATURES RISING SLOWLY BUT HAVE A LONG WAY TO GO STARTING BELOW ZERO. 400 AM UPDATE...MADE MINOR TWEAKS MAINLY TO CLD COVER AND TEMPS ERLY THIS MORNING AS LOW CLDS STUBBORNLY HANG ON DOWNWIND OF LAKE ONTARIO. I SUSPECT THESE CLDS WILL DISSIPATE AFTER SUNRISE. ALSO HAVE A FEW FLURRIES FROM THESE CLOUDS AS SURFACE TEMPS ARE CLOSE TO THE MAX ICE CRYSTAL GROWTH RATE...SUGGESTING ANY OROGRAPHIC LIFTING CAN EASILY SQUEEZE OUT A FLURRY OR TWO. PREVIOUS DISCUSSION BELOW FROM 1 AM UPDATE... IR IMAGERY AND GOES 11-3.9 MICRON IMAGERY SHOWS PESKY LOW LAKE EFFECT CLOUDS HANGING ON UNDER A SHARP VERY LOW-LEVEL INVERSION WITHIN A SHALLOW NORTHWEST FLOW IN EC NY. KBGM 88D VWP SHOWS A 340-350 DEGREE WIND AT 10 KTS ABT 500 FEET AGL AND ALMOST LIGHT AND VARIABLE ABOVE THIS. THIS LOW CLOUD LAYER THAT WAS MAINLY DOWNWIND OF THE FINGER LAKES AND LAKE ONTARIO WAS SHRINKING AND WILL CONTINUE TO DO SO AS THE LATEST RAP 925 MB LAYER WINDS BETWEEEN 6 AND 9Z TURN MORE NORTH TO NORTHEAST AND WEAKEN...LOSING THE OVERLAKE TRAJECTORIES. IN ADDITION OUR LOCAL WRF MODEL WITH ITS HOURLY OUTPUT ALSO IS VERY SIMILAR AND DIMINISHES THE LOW CLD COVER IN A SIMILAR FASHION AS PER THE DRYING OF THE 925 MB LAYER AS THE 925 MB WINDS SHIFT MORE NRLY AND LOSE LAKE TRAJECTORIES. HENCE HAVE CLOUDS DIMINISHING FOR THE REMAINDER OF THE EARLY MORNING HOURS. MINS WILL BE TRICKY GIVING THE WIDE RANGE OF TEMPERATURES OBSERVED AT PRESENT DUE TO CLD CVR. IN CLD CVR AREAS TEMPS ARE IN THE TEENS WITH TEMPERATURES RAPIDLY DROPPING TO NEAR ZERO IN CLR SKY AREAS. I HAVE MINS RANGING FROM SUB ZERO SINGLE DIGITS MAINLY TO SINGLE DIGITS WHERE CLD CLEAR LATEST IN EC NY. FOR SUNDAY...SFC HIGH PRESSURE RDG AXIS IS OVHD AT 12Z AND RAPIDLY SHIFTS EAST DURING THE DAY...REACHING OFFSHORE BY EVENING. MEANWHILE NEXT STORM WAS BEGINNING TO WORK EASTWARD. THE 850 AND 925 MB WAA BEGINS DURING THE DAY AS SOUTHERLY WINDS INCREASE...THIS WILL ALSO POP UP AN UPPER LEVEL RDG OVHD DURING THE DAY SUNDAY. SOME HIGHER CLDS WILL ADVECT IN OVER THE UPR RDG... BUT THE DEEPER MID LAYER CLDS HOLD OFF MOST OF THE DAY REACHING WRN NY LATE. I SEE MAINLY CIRRUS OVERSPREADING C NY AND NE PA DURING AFTERNOON WITH A MILDER DAY IN STORE DUE TO LL WARM ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... ALL 00Z MODELS...INCLUDING THE NAM12...GFS40...CMC AND EURO ALL TRACK THE NEXT SIGNIFICANT CYCLONE TRACKING INTO WI BY 6Z MONDAY. AT UPPER LEVELS THERE WAS A LOW OVER THE WESTERN LAKES REGION WITH A PERSISTENT UPPER LVL RDG OFF THE SE COAST TO THE WRN GULF COAST. AS A RESULT OF THIS UPPER LEVEL GEOPOTENTIAL FIELD...THERE WAS A STRONG UPPER LEVEL JET STREAK THAT WILL PUNCH INTO THE OHIO VALLEY BETWEEN 6Z AND 18Z MONDAY. THIS WILL INDUCED A STRONG SOUTHERLY LOW-LEVEL JET ARND 850 MB UP INTO NY AND PA TONIGHT/ERLY MON. THIS LLJ WILL FEATURE STRONG MOISTURE ADVECTION AND RISE ISENTROPICALLY. ALL MODELS AGREE THAT PRECIP SPREADS FROM WEST TO EAST ACROSS CENTRAL NY AND NE PA BTWN 6Z AND 12Z MONDAY. WILL RAMP POPS UP TO CATEGORICAL BY 12Z ALL FORECAST AREA. NOW TO P-TYPE. INITIALLY TEMPERATURES AND DEWPOINTS MOST OF CWA WILL BE BELOW FREEZING WITH SUB FREEZING DWPTS AS WELL LATE TONIGHT. MODEL GUIDC SUGGESTS OUR DOWNSLOPE REGIONS IN THE NRN FINGER LAKES ACTUALLY REMAIN ABV FREEZING WHICH IS NOT UNUSUAL TONIGHT. SO I WUD EXPECT STEADY AND SLOWING RISING TEMPERATURES SUNDAY NIGHT REST OF ZFORECAST AREA. WHEN PRECIP ARRIVES IT WILL BE MAINLY ZR INITIALLY WITH POSSIBLY SOME IP...BUT WITH 850 MB TEMPS ABV FREEZING DON/T SEE SNOW. PRECIPITATION WILL RAPIDLY TURN OVER TO PLAIN RAIN MONDAY DURING THE MORNING MOST OF CWA AS TEMPS WARM ABV FREEZING. THE LAST HOLD OUTS WILL BE IN THE FAR EASTERN PART OF THE CWA FROM SULLIVAN CO TO THE UPPER MOHAWK VALLEY WHERE ZR WILL LAST UNTIL AFTERNOON. ICE AMNTS WILL BE LIGHT...GENERALLY UNDER .1 INCHES...HOWEVER I SEE SOME AREAS IN THE CATSKILLS TO MOHAWK VALLEY SEEING MAYBE UP TO .15 INCH. MAIN IMPACT WILL BE TO TRAVEL. FOR NOW HELD OFF ON ISSUING ANY FLAGS FOR FREEZING RAIN AS NOT SURE AS TO THE EXTENT OR AREAL COVERAGE OF THE ICING. THERE IS PLENTY OF TIME AT THIS POINT IN OUR FORECAST AREA SO WILL LET DAY SHIFT HANDLE. I SUSPECT AN ADVY WILL BE ISSUED FOR A LARGE PART OF THE FORECAST AREA THIS AFTERNOON FOR LATE TONIGHT/MONDAY MORNING. THEN BY AFTERNOON MONDAY...RAIN SHEILD ASSOCIATED WITH WARM/MOIST CONVEYOR BELT IS EAST OF REGION AND THE COLD FRONT WILL SWING THRU BETWEEN 21Z MON AND 02Z TUE. THIS FEATURE WILL BE ACCOMPANIED BY CAA AND MAINLY SNOW SHOWERS WHICH WILL MIX WITH RAIN SHOWERS INITIALLY. FOR MONDAY NIGHT INTO EARLY TUESDAY...THE LL FLOW IS MORE W-SW WHICH SHUD DIRECTLY ANY LAKE MOISTURE AND DEVELOPING LES MAINLY N OF THE BGM FORECAST AREA. H85 TEMPS AT THIS POINT WILL BE MARGINAL AT BEST SO DOESN/T LOOK LIKE MUCH BEFORE TUE AM IN C NY OR NE PA OTHER THAN A FEW SNOW SHOWERS OR FLURRIES. THEN TUE INTO TUE NGT...ANOTHER WAVE AND ASSOCIATED COLD FRONT AND SURGE OF COLDER AIR PRESSES SOUTH TWD NY AND TURNS THE LL FLOW MORE W-NW WHICH COMBINED WITH H85 TEMPS DROPPING TO -12C SHUD TRIGGER SOME LAKE RESPONSE. FOR NOW HAVE POPS IN FOR LES NC NY LATER TUE INTO TUE NGT. THE NAM HOLDS ONTO THE LES LONGER THRU TUE NGT...GFS BACKS FLOW QUICKER TUE NGT. NOT SURE EXACTLY ON TIMING THIS FAR OUT SO PRETTY MUCH WENT WITH SCENARIO THAT KEEPS THE LES IN LONGER NC NY. NOT LOOKING FOR A MAJOR EVENT. GFS AND NAM SOUNDINGS FOR SYR SHOW INVERSION BARELY AT 850 MB AND MAX LIFT BELOW THE MAX GROWTH RATE FOR ICE CRYSTALS. I CUD SEE A FEW INCHES BUT NO WARNING AMNTS FOR LAKE SNOW BELTS IN NC NY...SO NO LES WATCH. REST OF FORECAST AREA WILL SEE TYPICAL BKN SC LAYER WITH SCATTERED FLURRIES OR EVEN SNOW SHOWERS WITH THE DAY/S HEATING. NO ACCUMS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... NOT A DEAD QUIET PATTERN...BUT NOTHING BIG GOING ON EITHER...AT LEAST NOT YET. THIS PERIOD WILL FEATURE A SPLIT FLOW PATTERN WITH ALTERNATING WEAK NORTHERN STREAM AND SOUTHERN STREAM WAVES JUST BARELY SKIMMING BY THE AREA. TEMPERATURES WILL BE NEAR OR JUST A TOUCH ABOVE CLIMATOLOGY. I WAS COMFORTABLE FOLLOWING HPC GUIDANCE INCLUDING JUST SLIGHT TO LOW CHANCE POPS...AND MAINLY SNOW SHOWERS AS PRECIP TYPE...THOUGH PERHAPS MIXED WITH RAIN BY FRIDAY AS FLOW BECOMES MORE SOUTHWESTERLY. MORE AMPLIFICATION TO THE FLOW OCCURS HEADING INTO THE WEEKEND...SO WE WILL HAVE TO SEE IF MORE SIGNIFICANT WAVES WILL BE ABLE TO IMPACT OUR WEATHER BY THEN. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... PERSISTENT LOW CLDS CONTS TO DRIFT OFF LAKE ONTARIO THIS MRNG BRING MVFR AND IFR CIGS TO SOME OF THE TAF SITES. XPCT HTG AND HIPRES TO FNLY LIFT THESE CLDS AWAY FROM THE AREA LEAVING VFR CONDS LTR THIS MRNG. VFR CONDS WILL REMAIN THRU MUCH OF THE PD UNTIL A WRM FNT APRCHS FROM THE WEST. THIS WILL BRING CLDS AND OVERRIDING WRM AIR. THE RESULT WILL BE CIGS LWRD TO MVFR LVLS AND MVFR VSBYS IN MIXED PCPN. .OUTLOOK... MON...MVFR/IFR IN LIGHT WINTRY MIX LATE SUN NIGHT INTO MON MORNING /INCLUDING FREEZING RAIN/...CHANGING TO ALL RAIN MON. MON NGT/TUE/TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED/THU...VFR MUCH OF THE TIME...BUT MVFR -SN POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN/TAC NEAR TERM...DJN/TAC SHORT TERM...DJN LONG TERM...MDP AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
648 AM EST SUN FEB 10 2013 .SYNOPSIS... SUNNY AND MILDER WEATHER IS EXPECTED TODAY AS HIGH PRESSURE MOVES OFF THE EAST COAST AND A SOUTHERLY FLOW OF AIR DEVELOPS. A LOW PRESSURE SYSTEM WILL BRING A LIGHT WINTRY MIX INCLUDING FREEZING RAIN LATE TONIGHT INTO MONDAY MORNING...WITH A TRANSITION TO PLAIN RAIN MONDAY. AFTER THIS LOW PRESSURE SYSTEM PASSES BY TO THE NORTHEAST MONDAY NIGHT, IT WILL SWING A COLD FRONT THROUGH THE AREA WITH A RETURN TO COLDER TEMPERATURES. THIS WILL LEAD TO SNOW SHOWERS AND FLURRIES DOWNWIND OF LAKE ONTARIO AND LAKE ERIE UNTIL WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 400 AM UPDATE...MADE MINOR TWEEKS MAINLY TO CLD COVER AND TEMPS ERLY THIS MORNING AS LOW CLDS STUBBORNLY HANG ON DOWNWIND OF LAKE ONTARIO. I SUSPECT THESE CLDS WILL DISSIPATE AFTER SUNRISE. ALSO HAVE A FEW FLURRIES FROM THESE CLOUDS AS SURFACE TEMPS ARE CLOSE TO THE MAX ICE CRYSTAL GROWTH RATE...SUGGESTING ANY OROGRAPHIC LIFTING CAN EASILY SQUEEZE OUT A FLURRY OR TWO. PREVIOUS DISCUSSION BELOW FROM 1 AM UPDATE... IR IMAGERY AND GOES 11-3.9 MIRCON IMAGERY SHOWS PESKY LOW LAKE EFFECT CLOUDS HANGING ON UNDER A SHARP VERY LOW-LEVEL INVERSION WITHIN A SHALLOW NORTHWEST FLOW IN EC NY. KBGM 88D VWP SHOWS A 340-350 DEGREE WIND AT 10 KTS ABT 500 FEET AGL AND ALMOST LIGHT AND VARIABLE ABOVE THIS. THIS LOW CLOUD LAYER THAT WAS MAINLY DOWNWIND OF THE FINGER LAKES AND LAKE ONTARIO WAS SHRINKING AND WILL CONTINUE TO DO SO AS THE LATEST RAP 925 MB LAYER WINDS BETWEEEN 6 AND 9Z TURN MORE NORTH TO NORTHEAST AND WEAKEN...LOSING THE OVERLAKE TRAJECTORIES. IN ADDITION OUR LOCAL WRF MODEL WITH ITS HOURLY OUTPUT ALSO IS VERY SIMILAR AND DIMINISHES THE LOW CLD COVER IN A SIMILAR FASHION AS PER THE DRYING OF THE 925 MB LAYER AS THE 925 MB WINDS SHIFT MORE NRLY AND LOSE LAKE TRAJECTORIES. HENCE HAVE CLOUDS DIMINISHING FOR THE REMAINDER OF THE EARLY MORNING HOURS. MINS WILL BE TRICKY GIVING THE WIDE RANGE OF TEMPERATURES OBSERVED AT PRESENT DUE TO CLD CVR. IN CLD CVR AREAS TEMPS ARE IN THE TEENS WITH TEMPERATURES RAPIDLY DROPPING TO NEAR ZERO IN CLR SKY AREAS. I HAVE MINS RANGING FROM SUB ZERO SINGLE DIGITS MAINLY TO SINGLE DIGITS WHERE CLD CLEAR LATEST IN EC NY. FOR SUNDAY...SFC HIGH PRESSURE RDG AXIS IS OVHD AT 12Z AND RAPIDLY SHIFTS EAST DURING THE DAY...REACHING OFFSHORE BY EVENING. MEANWHILE NEXT STORM WAS BEGINNING TO WORK EASTWARD. THE 850 AND 925 MB WAA BEGINS DURING THE DAY AS SOUTHERLY WINDS INCREASE...THIS WILL ALSO POP UP AN UPPER LEVEL RDG OVHD DURING THE DAY SUNDAY. SOME HIGHER CLDS WILL ADVECT IN OVER THE UPR RDG... BUT THE DEEPER MID LAYER CLDS HOLD OFF MOST OF THE DAY REACHING WRN NY LATE. I SEE MAINLY CIRRUS OVERSPREADING C NY AND NE PA DURING AFTERNOON WITH A MILDER DAY IN STORE DUE TO LL WARM ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... ALL 00Z MODELS...INCLUDING THE NAM12...GFS40...CMC AND EURO ALL TRACK THE NEXT SIGNIFICANT CYCLONE TRACKING INTO WI BY 6Z MONDAY. AT UPPER LEVELS THERE WAS A LOW OVER THE WESTERN LAKES REGION WITH A PERSISTENT UPPER LVL RDG OFF THE SE COAST TO THE WRN GULF COAST. AS A RESULT OF THIS UPPER LEVEL GEOPOTENTIAL FIELD...THERE WAS A STRONG UPPER LEVEL JET STREAK THAT WILL PUNCH INTO THE OHIO VALLEY BETWEEN 6Z AND 18Z MONDAY. THIS WILL INDUCED A STRONG SOUTHERLY LOW-LEVEL JET ARND 850 MB UP INTO NY AND PA TONIGHT/ERLY MON. THIS LLJ WILL FEATURE STRONG MOISTURE ADVECTION AND RISE ISENTROPICALLY. ALL MODELS AGREE THAT PRECIP SPREADS FROM WEST TO EAST ACROSS CENTRAL NY AND NE PA BTWN 6Z AND 12Z MONDAY. WILL RAMP POPS UP TO CATEGORICAL BY 12Z ALL FORECAST AREA. NOW TO P-TYPE. INITIALLY TEMPERATURES AND DEWPOINTS MOST OF CWA WILL BE BELOW FREEZING WITH SUB FREEZING DWPTS AS WELL LATE TONIGHT. MODEL GUIDC SUGGESTS OUR DOWNSLOPE REGIONS IN THE NRN FINGER LAKES ACTUALLY REMAIN ABV FREEZING WHICH IS NOT UNUSUAL TONIGHT. SO I WUD EXPECT STEADY AND SLOWING RISING TEMPERATURES SUNDAY NIGHT REST OF ZFORECAST AREA. WHEN PRECIP ARRIVES IT WILL BE MAINLY ZR INITIALLY WITH POSSIBLY SOME IP...BUT WITH 850 MB TEMPS ABV FREEZING DON/T SEE SNOW. PRECIPITATION WILL RAPIDLY TURN OVER TO PLAIN RAIN MONDAY DURING THE MORNING MOST OF CWA AS TEMPS WARM ABV FREEZING. THE LAST HOLD OUTS WILL BE IN THE FAR EASTERN PART OF THE CWA FROM SULLIVAN CO TO THE UPPER MOHAWK VALLEY WHERE ZR WILL LAST UNTIL AFTERNOON. ICE AMNTS WILL BE LIGHT...GENERALLY UNDER .1 INCHES...HOWEVER I SEE SOME AREAS IN THE CATSKILLS TO MOHAWK VALLEY SEEING MAYBE UP TO .15 INCH. MAIN IMPACT WILL BE TO TRAVEL. FOR NOW HELD OFF ON ISSUING ANY FLAGS FOR FREEZING RAIN AS NOT SURE AS TO THE EXTENT OR AREAL COVERAGE OF THE ICING. THERE IS PLENTY OF TIME AT THIS POINT IN OUR FORECAST AREA SO WILL LET DAY SHIFT HANDLE. I SUSPECT AN ADVY WILL BE ISSUED FOR A LARGE PART OF THE FORECAST AREA THIS AFTERNOON FOR LATE TONIGHT/MONDAY MORNING. THEN BY AFTERNOON MONDAY...RAIN SHEILD ASSOCIATED WITH WARM/MOIST CONVEYOR BELT IS EAST OF REGION AND THE COLD FRONT WILL SWING THRU BETWEEN 21Z MON AND 02Z TUE. THIS FEATURE WILL BE ACCOMPANIED BY CAA AND MAINLY SNOW SHOWERS WHICH WILL MIX WITH RAIN SHOWERS INITIALLY. FOR MONDAY NIGHT INTO EARLY TUESDAY...THE LL FLOW IS MORE W-SW WHICH SHUD DIRECTLY ANY LAKE MOISTURE AND DEVELOPING LES MAINLY N OF THE BGM FORECAST AREA. H85 TEMPS AT THIS POINT WILL BE MARGINAL AT BEST SO DOESN/T LOOK LIKE MUCH BEFORE TUE AM IN C NY OR NE PA OTHER THAN A FEW SNOW SHOWERS OR FLURRIES. THEN TUE INTO TUE NGT...ANOTHER WAVE AND ASSOCIATED COLD FRONT AND SURGE OF COLDER AIR PRESSES SOUTH TWD NY AND TURNS THE LL FLOW MORE W-NW WHICH COMBINED WITH H85 TEMPS DROPPING TO -12C SHUD TRIGGER SOME LAKE RESPONSE. FOR NOW HAVE POPS IN FOR LES NC NY LATER TUE INTO TUE NGT. THE NAM HOLDS ONTO THE LES LONGER THRU TUE NGT...GFS BACKS FLOW QUICKER TUE NGT. NOT SURE EXACTLY ON TIMING THIS FAR OUT SO PRETTY MUCH WENT WITH SCENARIO THAT KEEPS THE LES IN LONGER NC NY. NOT LOOKING FOR A MAJOR EVENT. GFS AND NAM SOUNDINGS FOR SYR SHOW INVERSION BARELY AT 850 MB AND MAX LIFT BELOW THE MAX GROWTH RATE FOR ICE CRYSTALS. I CUD SEE A FEW INCHES BUT NO WARNING AMNTS FOR LAKE SNOW BELTS IN NC NY...SO NO LES WATCH. REST OF FORECAST AREA WILL SEE TYPICAL BKN SC LAYER WITH SCATTERED FLURRIES OR EVEN SNOW SHOWERS WITH THE DAY/S HEATING. NO ACCUMS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... NOT A DEAD QUIET PATTERN...BUT NOTHING BIG GOING ON EITHER...AT LEAST NOT YET. THIS PERIOD WILL FEATURE A SPLIT FLOW PATTERN WITH ALTERNATING WEAK NORTHERN STREAM AND SOUTHERN STREAM WAVES JUST BARELY SKIMMING BY THE AREA. TEMPERATURES WILL BE NEAR OR JUST A TOUCH ABOVE CLIMATOLOGY. I WAS COMFORTABLE FOLLOWING HPC GUIDANCE INCLUDING JUST SLIGHT TO LOW CHANCE POPS...AND MAINLY SNOW SHOWERS AS PRECIP TYPE...THOUGH PERHAPS MIXED WITH RAIN BY FRIDAY AS FLOW BECOMES MORE SOUTHWESTERLY. MORE AMPLIFICATION TO THE FLOW OCCURS HEADING INTO THE WEEKEND...SO WE WILL HAVE TO SEE IF MORE SIGNIFICANT WAVES WILL BE ABLE TO IMPACT OUR WEATHER BY THEN. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... PERSISTENT LOW CLDS CONTS TO DRIFT OFF LAKE ONTARIO THIS MRNG BRING MVFR AND IFR CIGS TO SOME OF THE TAF SITES. XPCT HTG AND HIPRES TO FNLY LIFT THESE CLDS AWAY FROM THE AREA LEAVING VFR CONDS LTR THIS MRNG. VFR CONDS WILL REMAIN THRU MUCH OF THE PD UNTIL A WRM FNT APRCHS FROM THE WEST. THIS WILL BRING CLDS AND OVERRIDING WRM AIR. THE RESULT WILL BE CIGS LWRD TO MVFR LVLS AND MVFR VSBYS IN MIXED PCPN. .OUTLOOK... MON...MVFR/IFR IN LIGHT WINTRY MIX LATE SUN NIGHT INTO MON MORNING /INCLUDING FREEZING RAIN/...CHANGING TO ALL RAIN MON. MON NGT/TUE/TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED/THU...VFR MUCH OF THE TIME...BUT MVFR -SN POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN NEAR TERM...DJN SHORT TERM...DJN LONG TERM...MDP AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
449 AM EST SUN FEB 10 2013 .SYNOPSIS... SUNNY AND MILDER WEATHER IS EXPECTED TODAY AS HIGH PRESSURE MOVES OFF THE EAST COAST AND A SOUTHERLY FLOW OF AIR DEVELOPS. A LOW PRESSURE SYSTEM WILL BRING A LIGHT WINTRY MIX INCLUDING FREEZING RAIN LATE TONIGHT INTO MONDAY MORNING...WITH A TRANSITION TO PLAIN RAIN MONDAY. AFTER THIS LOW PRESSURE SYSTEM PASSES BY TO THE NORTHEAST MONDAY NIGHT, IT WILL SWING A COLD FRONT THROUGH THE AREA WITH A RETURN TO COLDER TEMPERATURES. THIS WILL LEAD TO SNOW SHOWERS AND FLURRIES DOWNWIND OF LAKE ONTARIO AND LAKE ERIE UNTIL WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 400 AM UPDATE...MADE MINOR TWEEKS MAINLY TO CLD COVER AND TEMPS ERLY THIS MORNING AS LOW CLDS STUBBORNLY HANG ON DOWNWIND OF LAKE ONTARIO. I SUSPECT THESE CLDS WILL DISSIPATE AFTER SUNRISE. ALSO HAVE A FEW FLURRIES FROM THESE CLOUDS AS SURFACE TEMPS ARE CLOSE TO THE MAX ICE CRYSTAL GROWTH RATE...SUGGESTING ANY OROGRAPHIC LIFTING CAN EASILY SQUEEZE OUT A FLURRY OR TWO. PREVIOUS DISCUSSION BELOW FROM 1 AM UPDATE... IR IMAGERY AND GOES 11-3.9 MIRCON IMAGERY SHOWS PESKY LOW LAKE EFFECT CLOUDS HANGING ON UNDER A SHARP VERY LOW-LEVEL INVERSION WITHIN A SHALLOW NORTHWEST FLOW IN EC NY. KBGM 88D VWP SHOWS A 340-350 DEGREE WIND AT 10 KTS ABT 500 FEET AGL AND ALMOST LIGHT AND VARIABLE ABOVE THIS. THIS LOW CLOUD LAYER THAT WAS MAINLY DOWNWIND OF THE FINGER LAKES AND LAKE ONTARIO WAS SHRINKING AND WILL CONTINUE TO DO SO AS THE LATEST RAP 925 MB LAYER WINDS BETWEEEN 6 AND 9Z TURN MORE NORTH TO NORTHEAST AND WEAKEN...LOSING THE OVERLAKE TRAJECTORIES. IN ADDITION OUR LOCAL WRF MODEL WITH ITS HOURLY OUTPUT ALSO IS VERY SIMILAR AND DIMINISHES THE LOW CLD COVER IN A SIMILAR FASHION AS PER THE DRYING OF THE 925 MB LAYER AS THE 925 MB WINDS SHIFT MORE NRLY AND LOSE LAKE TRAJECTORIES. HENCE HAVE CLOUDS DIMINISHING FOR THE REMAINDER OF THE EARLY MORNING HOURS. MINS WILL BE TRICKY GIVING THE WIDE RANGE OF TEMPERATURES OBSERVED AT PRESENT DUE TO CLD CVR. IN CLD CVR AREAS TEMPS ARE IN THE TEENS WITH TEMPERATURES RAPIDLY DROPPING TO NEAR ZERO IN CLR SKY AREAS. I HAVE MINS RANGING FROM SUB ZERO SINGLE DIGITS MAINLY TO SINGLE DIGITS WHERE CLD CLEAR LATEST IN EC NY. FOR SUNDAY...SFC HIGH PRESSURE RDG AXIS IS OVHD AT 12Z AND RAPIDLY SHIFTS EAST DURING THE DAY...REACHING OFFSHORE BY EVENING. MEANWHILE NEXT STORM WAS BEGINNING TO WORK EASTWARD. THE 850 AND 925 MB WAA BEGINS DURING THE DAY AS SOUTHERLY WINDS INCREASE...THIS WILL ALSO POP UP AN UPPER LEVEL RDG OVHD DURING THE DAY SUNDAY. SOME HIGHER CLDS WILL ADVECT IN OVER THE UPR RDG... BUT THE DEEPER MID LAYER CLDS HOLD OFF MOST OF THE DAY REACHING WRN NY LATE. I SEE MAINLY CIRRUS OVERSPREADING C NY AND NE PA DURING AFTERNOON WITH A MILDER DAY IN STORE DUE TO LL WARM ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... ALL 00Z MODELS...INCLUDING THE NAM12...GFS40...CMC AND EURO ALL TRACK THE NEXT SIGNIFICANT CYCLONE TRACKING INTO WI BY 6Z MONDAY. AT UPPER LEVELS THERE WAS A LOW OVER THE WESTERN LAKES REGION WITH A PERSISTENT UPPER LVL RDG OFF THE SE COAST TO THE WRN GULF COAST. AS A RESULT OF THIS UPPER LEVEL GEOPOTENTIAL FIELD...THERE WAS A STRONG UPPER LEVEL JET STREAK THAT WILL PUNCH INTO THE OHIO VALLEY BETWEEN 6Z AND 18Z MONDAY. THIS WILL INDUCED A STRONG SOUTHERLY LOW-LEVEL JET ARND 850 MB UP INTO NY AND PA TONIGHT/ERLY MON. THIS LLJ WILL FEATURE STRONG MOISTURE ADVECTION AND RISE ISENTROPICALLY. ALL MODELS AGREE THAT PRECIP SPREADS FROM WEST TO EAST ACROSS CENTRAL NY AND NE PA BTWN 6Z AND 12Z MONDAY. WILL RAMP POPS UP TO CATEGORICAL BY 12Z ALL FORECAST AREA. NOW TO P-TYPE. INITIALLY TEMPERATURES AND DEWPOINTS MOST OF CWA WILL BE BELOW FREEZING WITH SUB FREEZING DWPTS AS WELL LATE TONIGHT. MODEL GUIDC SUGGESTS OUR DOWNSLOPE REGIONS IN THE NRN FINGER LAKES ACTUALLY REMAIN ABV FREEZING WHICH IS NOT UNUSUAL TONIGHT. SO I WUD EXPECT STEADY AND SLOWING RISING TEMPERATURES SUNDAY NIGHT REST OF ZFORECAST AREA. WHEN PRECIP ARRIVES IT WILL BE MAINLY ZR INITIALLY WITH POSSIBLY SOME IP...BUT WITH 850 MB TEMPS ABV FREEZING DON/T SEE SNOW. PRECIPITATION WILL RAPIDLY TURN OVER TO PLAIN RAIN MONDAY DURING THE MORNING MOST OF CWA AS TEMPS WARM ABV FREEZING. THE LAST HOLD OUTS WILL BE IN THE FAR EASTERN PART OF THE CWA FROM SULLIVAN CO TO THE UPPER MOHAWK VALLEY WHERE ZR WILL LAST UNTIL AFTERNOON. ICE AMNTS WILL BE LIGHT...GENERALLY UNDER .1 INCHES...HOWEVER I SEE SOME AREAS IN THE CATSKILLS TO MOHAWK VALLEY SEEING MAYBE UP TO .15 INCH. MAIN IMPACT WILL BE TO TRAVEL. FOR NOW HELD OFF ON ISSUING ANY FLAGS FOR FREEZING RAIN AS NOT SURE AS TO THE EXTENT OR AREAL COVERAGE OF THE ICING. THERE IS PLENTY OF TIME AT THIS POINT IN OUR FORECAST AREA SO WILL LET DAY SHIFT HANDLE. I SUSPECT AN ADVY WILL BE ISSUED FOR A LARGE PART OF THE FORECAST AREA THIS AFTERNOON FOR LATE TONIGHT/MONDAY MORNING. THEN BY AFTERNOON MONDAY...RAIN SHEILD ASSOCIATED WITH WARM/MOIST CONVEYOR BELT IS EAST OF REGION AND THE COLD FRONT WILL SWING THRU BETWEEN 21Z MON AND 02Z TUE. THIS FEATURE WILL BE ACCOMPANIED BY CAA AND MAINLY SNOW SHOWERS WHICH WILL MIX WITH RAIN SHOWERS INITIALLY. FOR MONDAY NIGHT INTO EARLY TUESDAY...THE LL FLOW IS MORE W-SW WHICH SHUD DIRECTLY ANY LAKE MOISTURE AND DEVELOPING LES MAINLY N OF THE BGM FORECAST AREA. H85 TEMPS AT THIS POINT WILL BE MARGINAL AT BEST SO DOESN/T LOOK LIKE MUCH BEFORE TUE AM IN C NY OR NE PA OTHER THAN A FEW SNOW SHOWERS OR FLURRIES. THEN TUE INTO TUE NGT...ANOTHER WAVE AND ASSOCIATED COLD FRONT AND SURGE OF COLDER AIR PRESSES SOUTH TWD NY AND TURNS THE LL FLOW MORE W-NW WHICH COMBINED WITH H85 TEMPS DROPPING TO -12C SHUD TRIGGER SOME LAKE RESPONSE. FOR NOW HAVE POPS IN FOR LES NC NY LATER TUE INTO TUE NGT. THE NAM HOLDS ONTO THE LES LONGER THRU TUE NGT...GFS BACKS FLOW QUICKER TUE NGT. NOT SURE EXACTLY ON TIMING THIS FAR OUT SO PRETTY MUCH WENT WITH SCENARIO THAT KEEPS THE LES IN LONGER NC NY. NOT LOOKING FOR A MAJOR EVENT. GFS AND NAM SOUNDINGS FOR SYR SHOW INVERSION BARELY AT 850 MB AND MAX LIFT BELOW THE MAX GROWTH RATE FOR ICE CRYSTALS. I CUD SEE A FEW INCHES BUT NO WARNING AMNTS FOR LAKE SNOW BELTS IN NC NY...SO NO LES WATCH. REST OF FORECAST AREA WILL SEE TYPICAL BKN SC LAYER WITH SCATTERED FLURRIES OR EVEN SNOW SHOWERS WITH THE DAY/S HEATING. NO ACCUMS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... NOT A DEAD QUIET PATTERN...BUT NOTHING BIG GOING ON EITHER...AT LEAST NOT YET. THIS PERIOD WILL FEATURE A SPLIT FLOW PATTERN WITH ALTERNATING WEAK NORTHERN STREAM AND SOUTHERN STREAM WAVES JUST BARELY SKIMMING BY THE AREA. TEMPERATURES WILL BE NEAR OR JUST A TOUCH ABOVE CLIMATOLOGY. I WAS COMFORTABLE FOLLOWING HPC GUIDANCE INCLUDING JUST SLIGHT TO LOW CHANCE POPS...AND MAINLY SNOW SHOWERS AS PRECIP TYPE...THOUGH PERHAPS MIXED WITH RAIN BY FRIDAY AS FLOW BECOMES MORE SOUTHWESTERLY. MORE AMPLIFICATION TO THE FLOW OCCURS HEADING INTO THE WEEKEND...SO WE WILL HAVE TO SEE IF MORE SIGNIFICANT WAVES WILL BE ABLE TO IMPACT OUR WEATHER BY THEN. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... SOME SHALLOW LL MOISTURE CONTS TO DRIFT OFF THE LAKES AND BRING MVFR/IFR CONDS TO ITH AND BGM. XPCT THIS TO SLOWLY ERODE OVRNGT AS THE WIND FLOW BECOMES LESS FVRBL. OTRW...XPCT VFR CONDS THRU THE PD AS HIGH PRES BLDS INTO THE AREA. LGT WINDS TODAY WILL BECOME SE AFT 00Z AS A WRM FNT APRCHS AHD OF A LOW MVG INTO THE LAKES. ANY PCPN WILL BEGIN AFT THE END OF THE TAF PD. .OUTLOOK... SUN NGT/MON...MVFR/IFR IN LIGHT WINTRY MIX LATE SUN NIGHT INTO MON MORNING /INCLUDING FREEZING RAIN/...CHANGING TO ALL RAIN MON. MON NGT/TUE/TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED/THU...VFR MUCH OF THE TIME...BUT MVFR -SN POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN NEAR TERM...DJN SHORT TERM...DJN LONG TERM...MDP AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
133 AM EST SUN FEB 10 2013 .SYNOPSIS... SUNNY AND MILDER WEATHER IS EXPECTED TODAY AS HIGH PRESSURE MOVES OFF THE EAST COAST AND A SOUTHERLY FLOW OF AIR DEVELOPS. A LOW PRESSURE SYSTEM WILL BRING A LIGHT WINTRY MIX INCLUDING FREEZING RAIN LATE TONIGHT INTO MONDAY MORNING...WITH A TRANSITION TO PLAIN RAIN MONDAY. AFTER THIS LOW PRESSURE SYSTEM PASSES BY TO THE NORTHEAST MONDAY NIGHT, IT WILL SWING A COLD FRONT THROUGH THE AREA WITH A RETURN TO COLDER TEMPERATURES. THIS WILL LEAD TO SNOW SHOWERS AND FLURRIES DOWNWIND OF LAKE ONTARIO AND LAKE ERIE UNTIL WEDNESDAY. && .NEAR TERM /THROUGH TODAY/... IR IMAGERY AND GOES 11-3.9 MIRCON IMAGERY SHOWS PESKY LOW LAKE EFFECT CLOUDS HANGING ON UNDER A SHARP VERY LOW-LEVEL INVERSION WITHIN A SHALLOW NORTHWEST FLOW IN EC NY. KBGM 88D VWP SHOWS A 340-350 DEGREE WIND AT 10 KTS ABT 500 FEET AGL AND ALMOST LIGHT AND VARIABLE ABOVE THIS. THIS LOW CLOUD LAYER THAT WAS MAINLY DOWNWIND OF THE FINGER LAKES AND LAKE ONTARIO WAS SHRINKING AND WILL CONTINUE TO DO SO AS THE LATEST RAP 925 MB LAYER WINDS BETWEEEN 6 AND 9Z TURN MORE NORTH TO NORTHEAST AND WEAKEN...LOSING THE OVERLAKE TRAJECTORIES. IN ADDITION OUR LOCAL WRF MODEL WITH ITS HOURLY OUTPUT ALSO IS VERY SIMILAR AND DIMINISHES THE LOW CLD COVER IN A SIMILAR FASHION AS PER THE DRYING OF THE 925 MB LAYER AS THE 925 MB WINDS SHIFT MORE NRLY AND LOSE LAKE TRAJECTORIES. HENCE HAVE CLOUDS DIMINISHING FOR THE REMAINDER OF THE EARLY MORNING HOURS. MINS WILL BE TRICKY GIVING THE WIDE RANGE OF TEMPERATURES OBSERVED AT PRESENT DUE TO CLD CVR. IN CLD CVR AREAS TEMPS ARE IN THE TEENS WITH TEMPERATURES RAPIDLY DROPPING TO NEAR ZERO IN CLR SKY AREAS. I HAVE MINS RANGING FROM SUB ZERO SINGLE DIGITS MAINLY TO SINGLE DIGITS WHERE CLD CLEAR LATEST IN EC NY. FOR SUNDAY...SFC HIGH PRESSURE RDG AXIS IS OVHD AT 12Z AND RAPIDLY SHIFTS EAST DURING THE DAY...REACHING OFFSHORE BY EVENING. MEANWHILE NEXT STORM WAS BEGINNING TO WORK EASTWARD. THE 850 AND 925 MB WAA BEGINS DURING THE DAY AS SOUTHERLY WINDS INCREASE...THIS WILL ALSO POP UP AN UPPER LEVEL RDG OVHD DURING THE DAY SUNDAY. SOME HIGHER CLDS WILL ADVECT IN OVER THE UPR RDG... BUT THE DEEPER MID LAYER CLDS HOLD OFF MOST OF THE DAY REACHING WRN NY LATE. I SEE MAINLY CIRRUS OVERSPREADING C NY AND NE PA DURING AFTERNOON WITH A MILDER DAY IN STORE DUE TO LL WARM ADVECTION. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... 3 PM UPDATE... MIDWEST STORM CENTER LIFTS NE INTO ONTARIO BUT AN OCCLUDED FRONT MOVES THROUGH MONDAY NIGHT WITH MIXED PRECIP. WITH HIGH CLOUDS SUNDAY EVE AND DRY AIR AT THE SFC TEMPERATURES WILL BE ABLE TO DROP BELOW FREEZING. 20S MOST AREAS AND TEENS IN THE FAR EAST. CLOUDS THICKEN AND LOWER WITH LIGHT PRECIP COMING IN AFTER MIDNIGHT...AND BEFORE SUNRISE. TOTAL AMOUNTS A QUARTER TO HALF AN INCH MOSTLY MONDAY AM. THE FRONT MAKES STEADY PROGRESS SO MIXED PRECIP WILL CHANGE TO RAIN BY NOON EXCEPT IN THE FAR EAST WHERE SOME SLEET COULD BE HAPPENING AT THE HIGHEST ELEVATIONS OF THE SRN TUG AND CATSKILLS. WITH FREEZING RAIN BEING SHORT LIVED AMOUNTS WILL BE LESS THAN A TENTH OF AN INCH. THE FINGER LAKES MAY GET NOTHING WITH TEMPERATURES RISING ABOVE FREEZING THE FASTEST AND EARLIEST. CONTINUE TO HIGHLIGHT THE FREEZING RAIN THREAT IN THE HWO. MONDAY NIGHT TO TUESDAY IN A BROAD TROF AS THE STACKED LOW PASSES WELL TO THE NORTH OF THE CWA IN SE CANADA. MULTIPLE SHORT WAVES AND A COLD FRONT WILL MOVE THROUGH MONDAY NIGHT BRINGING SOME LIGHT SNOW TO MAINLY CENTRAL NY. LESSER AMOUNTS WILL BE IN NE PA. TUESDAY MORE SNOW SHOWERS ENHANCED WITH LAKE MOISTURE. 850MB TEMPS FALL TO -12 WHICH IS NOT COLD ENOUGH FOR PURE LAKE EFFECT WITH LAKE TEMPS IN THE 30S. MORE SHORT WAVES AND A WEAK SFC TROF WILL PROVIDE LIFT. LOW LEVEL FLOW FROM THE WEST SO MOST OF THE SNOW SHOWERS WILL BE CONFINED TO UPSTATE NY. ON THE EDGE OF THE SYNOPTIC MOISTURE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... NOT A DEAD QUIET PATTERN...BUT NOTHING BIG GOING ON EITHER...AT LEAST NOT YET. THIS PERIOD WILL FEATURE A SPLIT FLOW PATTERN WITH ALTERNATING WEAK NORTHERN STREAM AND SOUTHERN STREAM WAVES JUST BARELY SKIMMING BY THE AREA. TEMPERATURES WILL BE NEAR OR JUST A TOUCH ABOVE CLIMATOLOGY. I WAS COMFORTABLE FOLLOWING HPC GUIDANCE INCLUDING JUST SLIGHT TO LOW CHANCE POPS...AND MAINLY SNOW SHOWERS AS PRECIP TYPE...THOUGH PERHAPS MIXED WITH RAIN BY FRIDAY AS FLOW BECOMES MORE SOUTHWESTERLY. MORE AMPLIFICATION TO THE FLOW OCCURS HEADING INTO THE WEEKEND...SO WE WILL HAVE TO SEE IF MORE SIGNIFICANT WAVES WILL BE ABLE TO IMPACT OUR WEATHER BY THEN. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... SOME SHALLOW LL MOISTURE CONTS TO DRIFT OFF THE LAKES AND BRING MVFR/IFR CONDS TO ITH AND BGM. XPCT THIS TO SLOWLY ERODE OVRNGT AS THE WIND FLOW BECOMES LESS FVRBL. OTRW...XPCT VFR CONDS THRU THE PD AS HIGH PRES BLDS INTO THE AREA. LGT WINDS TODAY WILL BECOME SE AFT 00Z AS A WRM FNT APRCHS AHD OF A LOW MVG INTO THE LAKES. ANY PCPN WILL BEGIN AFT THE END OF THE TAF PD. .OUTLOOK... SUN NGT/MON...MVFR/IFR IN LIGHT WINTRY MIX LATE SUN NIGHT INTO MON MORNING /INCLUDING FREEZING RAIN/...CHANGING TO ALL RAIN MON. MON NGT/TUE/TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED/THU...VFR MUCH OF THE TIME...BUT MVFR -SN POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN NEAR TERM...DJN SHORT TERM...TAC LONG TERM...MDP AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
725 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST TO OUR SOUTH LATE TONIGHT. WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT TUESDAY NIGHT AND WEDNESDAY...BRINGING UNSETTLED WEATHER. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 245 PM MONDAY... THROUGH TONIGHT: AS EXPECTED... THE WEDGE AIR MASS OVER THE TRIAD REGION HAS BEEN VERY TOUGH TO DISLODGE... AS EARLY AFTERNOON TEMPS REMAIN IN THE LOWER 50S WITH FOG AND VERY LOW STRATUS HOLDING ON... WHILE READINGS ARE MOSTLY IN THE 60S ELSEWHERE. SW WINDS JUST OFF THE SURFACE (AT 1-2 KFT AGL) ARE NOT QUITE AS STRONG AS THEY WERE THIS MORNING WITH THE DEPARTURE OF THE LOW LEVEL JET TO THE EAST BUT THEY CONTINUE TO PULL IN ENOUGH WARM AIR ALOFT SUCH THAT THE SURFACE-BASED STABLE LAYER IS REINFORCED VIA DIFFERENTIAL TEMP ADVECTION IN THE VERTICAL...DESPITE THE LACK OF A FEED OF COOL AIR AT THE SURFACE. AS SUCH...WE MAY SEE A MUTED FORM OF THIS WEDGE AIR MASS HANG IN OVER THE TRIAD THROUGH THIS EVENING... UNTIL THE COLD FRONT FINALLY SWEEPS THROUGH. LATEST CONVECTION-ALLOWING MODEL RUNS INCLUDING THE HRRR AND HIGH-RES WRF-NMM AND WRF-ARW SHOW WEAK LOW PRESSURE OVER NRN GA TRACKING ALONG THE FRONT AND IS ASSOCIATED WITH THE UPSTREAM PRECIP BAND NOW ACROSS NRN GA AND UPSTATE SC STREAMING TO THE ENE ACROSS THE FAR SRN/SE CWA... HOWEVER PREFRONTAL CONVECTION TO THE SSE OVER SRN GA MAY INTERRUPT THE POLEWARD MOISTURE TRANSPORT SUCH THAT WE`LL ONLY SEE LIGHT AMOUNTS AT MOST. WILL HOLD ONTO THE LOW CHANCE POPS OVER THE FAR SRN AND SE CWA THROUGH THIS EVENING... WITH DRY WEATHER OVERNIGHT. A SUBTLE MID LEVEL WAVE CONNECTED TO THE VORTEX CROSSING FAR SE ONTARIO AND SRN QUEBEC WILL CROSS THE MIDATLANTIC REGION LATER TONIGHT...FLATTENING THE MID LEVEL FLOW AND PROPELLING THE SURFACE FRONT TO OUR SOUTHEAST. THIS FLOW WILL REMAIN QUITE SWIFT TONIGHT...80-90 KTS AT 500 MB... WITH PLENTY OF MOISTURE AT 310K-320K...SO EXPECT ABUNDANT MID LEVEL CLOUDS TO STREAM ACROSS THE AREA THROUGH THE NIGHT. LOWS 39-47. FOR TUESDAY/TUESDAY NIGHT: WILL SEE A BRIEF RESPITE IN THE ACTIVE PATTERN ON TUESDAY BEFORE THE RAIN RAMPS BACK UP TUESDAY EVENING. THE FRONT WILL HOLD TO OUR SOUTH WITH WEAK HIGH PRESSURE BUILDING OVER THE REGION. MID LEVEL FLOW REMAINS FAST (NEAR 80 KTS) OVER THE REGION BUT WILL BECOME GENTLY ANTICYCLONIC FOR A TIME... AS THE DEEP TROUGH LOCATED OVER THE FOUR CORNERS REGION STARTS TO KICK EASTWARD INTO THE SRN PLAINS. WE`LL LIKELY SEE PARTLY SUNNY SKIES GIVE WAY TO GREATER SUNSHINE TOWARD AFTERNOON... PARTICULARLY ACROSS THE NORTHERN CWA. LOW LEVEL THICKNESSES AS WELL AS THE LOW LEVEL THERMAL STRUCTURE SUPPORT HIGHS IN THE UPPER 50S TO LOWER 60S. THE MID LEVEL TROUGH SHIFTS THROUGH THE MID MISS VALLEY AS A POSITIVELY-TILTED WEAKENING WAVE... AND MODELS ALL AGREE ON A RAPID INCREASE IN DEEP MOIST ISENTROPIC UPGLIDE FROM 285K-305K OUT AHEAD OVER THE CAROLINAS. SIMILAR TO LAST NIGHT`S RAINFALL PATTERN... WITH THE FRONT LIKELY TO STILL HOLD SOUTH OF THE NC BORDER THROUGH TUESDAY NIGHT AND WITH INCREASING LAPSE RATES AND INSTABILITY OVER MS/AL/GA... WE SHOULD SEE THE GREATEST RISK OF HEAVY PRECIP CONFINED TO ALONG AND SOUTH OF THE BORDER. WITH A GOOD CHANCE OF A CONVECTIVE BAND WELL TO OUR SOUTH AND SW TUESDAY NIGHT... MOISTURE TRANSPORT MAY BE SUFFICIENTLY REDUCED TO GREATLY LIMIT AMOUNTS AND COVERAGE OVER NRN NC. NEVERTHELESS... GIVEN THE RESURGENCE OF 1+ INCH PRECIP WATER INTO THE SRN AND ERN CWA OVERNIGHT... CONFIDENCE IS HIGH ENOUGH FOR CATEGORICAL POPS IN THE SRN/SE CWA... TRENDING TO GOOD CHANCE NEAR THE VA BORDER. AMOUNTS ALONG/NORTH OF HIGHWAY 64 MAY BE LESS THAN A TENTH... WHILE AREAS NEAR THE SC BORDER COULD SEE A HALF INCH OR MORE. LOWS 40-46. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 310 PM MONDAY... SHORTWAVE EJECTING OUT OF THE FOUR CORNERS REGION TUESDAY WILL RACE EAST ACROSS THE MS AND TN VALLEY REGIONS BY TUESDAY NIGHT NIGHT...SHEARING OUT AS IT CROSSES THE CAROLINAS ON WEDNESDAY. AS PRECIP SPREADS INTO THE AREA ON THE HEELS OF WEAK HIGH PRESSURE LATE TUESDAY NIGHT...ANOTHER CAD AIRMASS SHOULD DEVELOP OVER THE PIEDMONT. MODELS CONTINUE TO DIFFER REGARDING THE TRACK OF THE ASSOCIATED SURFACE LOW ALONG A STALLED OUT FRONTAL ZONE DRAPED ACROSS THE GULF/SOUTHEAST COAST. THE NAM CONTINUES TO BE THE NORTHERN OUTLIER WITH A LOW TRACK WEST OF THE MOUNTAINS. THE ECMWF APPEARS MORE REALISTIC WITH A TRACK ACROSS GA/SC TOWARD THE NC COAST. THE GFS SOMEWHERE IN BETWEEN TRACKING THE LOW TOWARD THE PIEDMONT...THEN JUMPING ACROSS THE EXPECTED CAD AIRMASS TO THE VA COAST. FAVORING A SOUTHERN TRACK OF THE LOW...THE BEST FOCUS OF DEEP MOISTURE AND LOW LEVEL CONVERGENCE WILL BE ACROSS SC TO SOUTHEAST NC...WHERE MODELS GIVE ONE HALF TO NEAR ONE INCH OF QPF IN TOTAL. AHEAD OF THE SHORTWAVE...MODELS SUGGEST A PLUME A STEEP MID LEVEL LAPSE RATES IN EXCESS OF -6.5 C/KM WITH A TRAJECTORY ACROSS CENTRAL NC. MODEST UPPER LEVEL FORCING FROM THE VORT MAX/LEFT EXIT REGION OF THE STJ...COMBINED WITH STRENGTHENING ISENTROPIC ACCENT IN THE LOW LEVELS...COULD LEAD TO A CHANCE OF THUNDER WEDNESDAY AFTERNOON. POPS WILL BE INCREASED TO ABOVE 80 PERCENT WITH THE HIGHEST VALUES SOUTH WEDNESDAY MORNING. HIGHS IN THE 40S TO POSSIBLY LOWER 50S IN THE SOUTHEAST. WESTERLY FLOW AND COLD/DRY ADVECTION IN THE WAKE OF THE DEPARTING SYSTEM SHOULD HELP TO SCOUR SOME OF THE LINGERING LOW CLOUDS WEDNESDAY NIGHT. LOWS IN THE LOW TO MID 30S. TEMPS SHOULD CLIMB BACK TO AROUND NORMAL ON THURSDAY WITH A LIGHT SOUTHWESTERLY WIND DEVELOPING AS HEIGHTS SLOWLY BEGIN TO FALL OVER THE CENTRAL US. HIGHS 52-57. LOWS THURSDAY NIGHT IN THE LOW TO MID 30S && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 310 PM MONDAY... MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE WEEKEND...WITH RIDGING OVER THE WESTERN US AND A DEEP TROUGH DEVELOPING OVER THE EASTERN US. DETAILS REGARDING THE STRENGTH AND TIMING SHORTWAVES ROTATING INTO THE EAST COAST TROUGH REMAIN SOMEWHAT UNCERTAIN...BUT MODELS CURRENTLY PROJECT A WEAKER TROUGH AND COLD FRONTAL PASSAGE FRIDAY... AND A MORE SUBSTANTIAL TROUGH ARRIVING SATURDAY/SATURDAY NIGHT. BASED ON THE ECMWF AND A CONSENSUS OF GEFS SOLUTIONS...HPC CONTINUES TO FAVOR CYCLOGENESIS OFF THE MID-ATLANTIC COAST SATURDAY NIGHT...SUPPORTING LESS IMPACT OVER THE CAROLINAS. HOWEVER...EVEN WITH RUN-TO-RUN INCONSISTENCIES IN THE GFS/ECMWF...MODELS SUGGEST THE UPPER TROUGH MAY BE STRONG ENOUGH TO OVERCOME THE RELATIVELY DRY AIR OVER CENTRAL NC AND PRODUCE SOME LIGHT QPF. FORECAST LOW LEVEL THICKNESSES PLUMMET WELL BELOW 1300M WITH THE SECOND TROUGH ON SATURDAY....SO CONFIDENCE IS MODERATELY HIGH IN THERMAL PROFILES WILL BECOME FAVORABLE FOR SNOW SHOWERS. THE MAIN QUESTION WILL BE MOISTURE AVAILABILITY OR GENERATION FROM THE TROUGH....BUT THERE HAS BEEN ENOUGH CONSISTENCY IN THE MODELS TO INTRODUCE A SLIGHT CHANCE OF RAIN OR SNOW SHOWERS INTO THE FORECAST SATURDAY EVENING/NIGHT. TEMPS WILL BE TWO TO THREE CATEGORIES BELOW NORMAL SATURDAY AND ESPECIALLY SUNDAY. BEYOND SUNDAY...MODELS SHOW A RIDGE BUILDING EASTWARD ACROSS THE CENTRAL PORTION OF THE COUNTRY EARLY NEXT WEEK WITH A MODERATING TREND AND DRY CONDITIONS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 715 PM MONDAY... 24-HR TAF PERIOD: IFR (INT/GSO TERMINALS) AND MVFR CEILINGS (RDU/RWI TERMINALS) WILL LIFT AND SCATTER OUT TO VFR THIS EVENING AS A DRIER AIRMASS ADVECTS INTO CENTRAL NC IN THE WAKE OF A COLD FRONT PROGRESSING EAST THROUGH THE AREA BETWEEN 700 PM (00Z) AND MIDNIGHT (05Z). SOUTHWEST WINDS AT 7-12 KT WILL VEER TO THE WEST AT 5-10 KT BEHIND THE FRONT. VFR CONDITIONS WITH CEILINGS 12-15+ KFT AND WEST/NW WINDS AT 5-10 KT WILL PREDOMINATE OVER CENTRAL NC LATE TONIGHT THROUGH TUESDAY AS A DRIER AIRMASS SETTLES OVER THE REGION IN THE WAKE OF THE FRONT... WHICH IS EXPECTED TO STALL OUT OVER THE DEEP SOUTH AND THE SOUTHEAST COAST. LOOKING AHEAD: THE STALLED FRONT WILL LIFT BACK NORTH INTO THE CAROLINAS TUE NIGHT AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY IN ADVANCE OF AN APPROACHING UPPER LEVEL DISTURBANCE. EXPECT DETERIORATING CONDITIONS TUE NIGHT...WITH MVFR/IFR CEILINGS AND RAIN DEVELOPING AREA WIDE (SW-NE) BETWEEN MIDNIGHT AND SUNRISE WED MORNING... PERSISTING THROUGH THE DAY WED. STRENGTHENING FLOW ALOFT MAY RESULT IN A PERIOD OF SOUTHWESTERLY LOW-LEVEL WIND SHEAR WEDNESDAY AFTERNOON...MOST LIKELY AT INT/GSO...THOUGH POSSIBLE AT ALL TERMINALS DEPENDING ON THE ORIENTATION OF THE WARM FRONT AND EXACT TRACK OF THE SURFACE LOW. EXPECT A RAPID RETURN TO VFR CONDITIONS IN ASSOC/W A COLD FRONTAL PASSAGE WED EVENING INTO WED NIGHT...ALONG WITH A POTENTIAL FOR A BRIEF PERIOD OF STRONG W/NW WINDS. VFR CONDITIONS ARE EXPECTED TO PREVAIL IN THE WAKE OF THE COLD FRONT THE REMAINDER OF THE WORK WEEK. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
722 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS FROM THE WEST TONIGHT...FOLLOWED BY HIGH PRESSURE ON TUESDAY. A LOW PRESSURE AREA WILL MOVE NORTHEAST ALONG THE COAST WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT...FOLLOWED BY COLD HIGH PRESSURE OVER THE WEEKEND. && .NEAR TERM /TONIGHT/... AS OF 713 PM MONDAY...CURRENT RADAR PICTURES SHOWING ANOTHER BATCH OF LIGHT SHOWERS MOVING INTO AREA THIS EVENING. HRRR WAY OVERDONE ON PRECIP THIS EVENING...WITH RUC SEEMING TO HAVE A DECENT HANDLE. SHOWERS WILL MOVE OFFSHORE THROUGH EARLY MORNING AS FRONT APROACHES AREA. FRONT WILL PASS OFFSHORE SHORTLY BEFORE SUNRISE WITH WIND LIGHTENING AND BECOMING WESTERLY THEN NORTHWESTERLY BY SUNRISE. SKIES WILL REMAIN MOSTLY CLOUDY WITH CONTINUED MOISTURE IN THE ATMOSPHERIC COLUMN. TEMPERATURES WILL REMAIN NEARLY STEADY OVER NEXT FEW HOURS WITH CLOUD COVER/MOISTURE...THEN WILL DROP A LITTLE FASTER AFTER THE FRONT WITH MID 40S EXPECTED INLAND AND LOWER 50S ALONG THE COAST. && .SHORT TERM /TUESDAY/... AS OF 300 PM MONDAY...WITH SFC BNDRY STALLED S OF AREA ALONG WITH DEEPER MSTR BAND...AND WEAK RIDGING SFC AND ALOFT...EXPECT CONTINUED GRADUAL DECREASING CLOUDINESS DURING THE DAY AND PCPN THREAT TO REMAIN S OF AREA UNTIL LATE AFTN. WENT WITH BC MOS BLEND FOR MAX TEMPS...MID 50S N TO NEAR 60 S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AS OF 340 PM MONDAY...A DEVELOPING LOW PRESSURE WILL BE APPROACHING EASTERN NC TUESDAY NIGHT AND MOVING ACROSS OR JUST OFF OF THE EASTERN NC COAST WEDNESDAY. CONSENSUS OF THE MOST CONSISTENT MODELS TAKES THE LOW ACROSS THE COAST WEDNESDAY AS SEVERAL LOW CENTERS CONSOLIDATE.. THIS SYSTEM IS A REFLECTION OF A POTENT MID LEVEL SHORTWAVE AND WILL PRODUCE WIDESPREAD RAIN FROM MID TUESDAY EVENING THROUGH WEDNESDAY AFTERNOON. SOME LINGERING LIGHT RAIN AND/OR DRIZZLE WILL BE POSSIBLE INTO WEDNESDAY EVENING. NO REAL COLD AIR WILL BE ASSOCIATED WITH THIS SYSTEM SO THE PRECIPITATION WILL BE ALL RAIN WITH TOTAL RAINFALL AMOUNTS OF 0.50 TO 1" WITH LOCALLY HIGHER AMOUNTS ALONG THE COAST. DRY AND SEASONABLE WEATHER WILL BE FORECAST FROM THURSDAY AND FRIDAY AS HIGH PRESSURE MOVES ACROSS THE AREA. THE UPPER TROUGH IS FORECAST TO AMPLIFY ACROSS THE EASTERN US OVER THE WEEKEND WITH A LEAD COLD FRONT FORECAST TO CROSS THE AREA FRIDAY NIGHT. THE AIRMASS WILL BE DRY PRECEDING THE FRONT AND THIS WILL LIMIT PRECIPITATION CHANCES WITH THE FRONT SO WILL MAINTAIN DRY FORECAST ALTHOUGH ISOLATED SHOWERS WILL BE POSSIBLE FRIDAY EVENING. THE COLD AIR ACROSS EASTERN NC WILL BE REINFORCED BY SEVERAL SHORTWAVE MOVING THROUGH THE EASTERN UPPER TROUGH SATURDAY AND SUNDAY WITH CYCLOGENESIS EVENTUALLY OCCURRING WELL OFF OF THE COAST SATURDAY OR SUNDAY. RIGHT NOW IT LOOKS THE LOW WILL DEVELOP FAR ENOUGH OFFSHORE TO KEEP THE BULK OF THE PRECIPITATION OFFSHORE BUT WITH SUCH A DEEP TROUGH ALOFT THERE WILL BE A POSSIBILITY OF A FEW RAIN SHOWERS LATE SATURDAY AND SNOW SHOWERS SATURDAY NIGHT. OUR CURRENT FORECAST TEMPERATURES OF HIGHS AROUND 50 SATURDAY AND 40 TO 45 DEGREES SUNDAY MAY NEED TO BE LOWERED BASED ON FORECAST LOW LEVEL THICKNESSES. WILL KEEP SUNDAY DRY ALTHOUGH A FEW SNOW FLURRIES WILL BE POSSIBLE BEFORE HIGH PRESSURE BUILDS OVER THE AREA INTO MONDAY. && .AVIATION /00Z TUEDAY THROUGH FRIDAY/... SHORT TERM /THROUGH 00Z WEDNESDAY/... AS OF 640 PM MONDAY...ANOTHER BATCH OF LIGHT SHOWERS WILL MOVE INTO THE AREA OVER NEXT COUPLE OF HOURS WITH MVFR CIGS. FRONT OVER WESTERN PART OF STATE WILL MOVE OVER AREA TAF SITES SHORTLY AFTER MIDNIGHT. GUSTY SOUTHWEST WINDS HAVE DIMINISHED AS GRADIENT LOOSENS WITH APPROACHING FRONT. DIRECTION WILL BECOME WESTERLY BEHIND FROPA DURING THE EARLY MORNING HOURS...THEN NORTHWESTERLY AFTER SUNRISE. CONDITIONS WILL BECOME VFR BEHIND THE FRONT AS FORECAST SOUNDINGS SHOWING DRIER AIR MOVING IN. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 340 PM MONDAY...SUB VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY IN WIDESPREAD RAIN ASSOCIATED WITH LOW PRESSURE MOVING ACROSS THE AREA. DRY AIR MOVING INTO THE AREA WEDNESDAY NIGHT AND CONTINUING THROUGH FRIDAY WILL LEAD TO VFR CONDITIONS AS HIGH PRESSURE PREVAILS. ISOLATED RAIN SHOWERS WITH SUB VFR CONDITIONS WILL BE POSSIBLE SATURDAY. && .MARINE... SHORT TERM /THROUGH TUESDAY/... AS OF 721 PM MONDAY...SOUTHWEST WIND OVER THE WATERS THIS EVENING RANGING FROM THE MID-TEENS SOUTH OF HATTERAS TO 20-25KTS NORTH OF HATTERAS. WEATHERFLOW OBS SHOWING 23 KTS IN CENTRAL PAMLICO SOUND AND TRENDING UP. CONSIDERED DROPPING SCA...BUT WILL HOLD ONTO THEM FOR THE NEXT FEW HOURS AS WINDS COULD SURGE/GUST. FRONT IN WESTERN PART OF STATE WILL MOVE TOWARD THE WATERS OVER NEXT FEW HOURS...AND IS EXPECTED TO CROSS THE WATERS NEAR SUNRISE. DIRECTION WILL BECOME WESTERLY BEHIND THE FRONT. CAA SURGE FOLLOWING FRONTAL PASSAGE WILL BE MODERATE WITH SPEEDS MAINLY LESS THAN 20 KT...AND SUBSIDING QUICKLY DURING DAY TUE...LEADING TO DIMINISHING WINDS AND SEAS THROUGH THE DAY. BLEND OF PREVIOUS FCST...NWPS AND WW3 USED FOR SEAS. HEIGHTS PEAKING AT 7-10 FT THIS EVENING...THEN SUBSIDING BELOW 6 FT LATE TONIGHT AND TUE MORNING. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 340 PM MONDAY....CONDITIONS ON TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE DEPENDENT ON THE TRACK AND INTENSITY OF LOW PRESSURE WHICH APPROACH THE WATERS TUESDAY NIGHT AND MOVE ALONG OR JUST OFF OF THE NC COAST WEDNESDAY. CONSENSUS OF THE MOST CONSISTENT MODELS KEEPS SUB ADVISORY CONDITIONS TUESDAY NIGHT INTO EARLY WEDNESDAY THEN SMALL CRAFT ADVISORY CONDITIONS WILL BE FORECAST FOR LATE WEDNESDAY INTO THURSDAY. SOME OF THE GUIDANCE IS HINTING AT THE POTENTIAL FOR LOW END GALES WEDNESDAY NIGHT. CONDITIONS WILL IMPROVE LATE THURSDAY INTO FRIDAY AS HIGH PRESSURE BUILDS OVER THE WATERS. A COLD FRONT WILL CROSS THE WATERS FRIDAY NIGHT WITH NW FLOW INCREASING FROM 10 TO 15 KT FRIDAY NIGHT TO AT LEAST 15 TO 20 KT ON SATURDAY. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ135. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 10 AM EST TUESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ156-158. SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR AMZ150. && $$ SYNOPSIS...JBM NEAR TERM...CGG SHORT TERM...JBM LONG TERM...JME AVIATION...CGG/JME MARINE...CGG/JME
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
231 PM EST SUN FEB 10 2013 .SYNOPSIS... RAIN TONIGHT. COLD FRONT EARLY MONDAY. HIGH PRESSURE TUESDAY. LOW PRESSURE PASSES TO THE SOUTH WEDNESDAY. && .NEAR TERM /THROUGH MONDAY/... MODELS IN FAIRLY GOOD AGREEMENT WITH THE BAND OF PRECIPITATION MOVING THROUGH TONIGHT. WILL INCREASE POPS TO 100 PERCENT. WITH CLOUDS AND WINDS...WILL GO WITH WARMER MOS GUIDANCE FOR LOWS TONIGHT. COLD FRONT MOVES THROUGH EARLY MONDAY. WITH COLD AIR LAGGING CONSIDERABLY BEHIND THE FRONT...SHOULD SEE A GOOD DRY SLOT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AREA GETS INTO INCREASINGLY ALIGNED WSW FLOW AS UPPER LEVEL LOW TRAVERSES GREAT LAKES MON. DEEP LAYER MOISTURE EXITS FIRST THING IN THE MORNING...AS UPPER LEVEL JET MAX PASSES. THIS WILL LEAD TO INCREASINGLY MIXED AIR MASS THAT MAY BECOME DRY ADIABATIC ALL THE WAY TO H7. HAVE WINDS REACHING CRITERIA FOR ADV ONLY FOR HIGHEST ELEVATIONS SO FAR VIA RUC MOMENTUM MIXING ALGORITHM. HIGH PRESSURE SLOWLY BUILDS IN ON TUE...ONLY TO RETREAT TUE NT AS NEXT S/W TROF APPROACHES FROM THE W. ASSOCIATED CONFLUENCE ZONE SETS UP ACROSS NRN PA AS SFC LOW TRACKS TO THE S...THE GFS/ECMWF SOLN FAVORED OVER THE NAM12...WHICH IS THE ODD MODEL N. CANADIAN IS EVEN FURTHER S. HAVE LIMITED LIKELY POPS TO FAR S PORTION OF THE AREA. WHILE THIS IS A SYNOPTICALLY CORRECT TRACK FOR SNOW...BORING PACIFIC AIR MASS IN PLACE AHEAD OF THE SYSTEM LEAVES TEMPERATURES ONLY MARGINALLY LOW ENOUGH...ESPECIALLY AT THE SFC...GIVING RISE TO MIXED PRECIPITATION AND EVEN JUST RAIN. HAVE MINIMAL SNOW AMOUNTS OF JUST OVER AN INCH ON THE CENTRAL MOUNTAINS AS SYSTEM EXITS WED AFTERNOON...AND VERY LITTLE ICE. TOGETHER WITH POPS MAINLY IN THE CHANCE RANGE...HAVE NO HWO MENTION WARRANTED AT THIS POINT AS CONFIDENCE IN CODABLE WINTER EVENT IS QUITE LOW. BLENDED IN ADJMET FOR TEMPERATURES EARLY ON...THEN ADJMAV / ADJMEX TOWARD THE END IN LIGHT OF GFS SOLN. THIS KEEPS FCST LARGELY IN LINE WITH PREVIOUS PACKAGE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MDL TRENDS CONT TO CLOSE IN ON OP GFS SOLUTIONS AT LEAST REGARDING S/W TROF ON WED. 12Z ECWMF CONT THE TREND AS WELL. STILL SOME UNCERTAINTIES WITH SFC LOW TRACK...BUT ALL AGREE AT LEAST SOME INFLUENCE FROM INVERTED SFC TROUBLE. ELECTED TO RAISE POPS INTO LKLY ACROSS SW VA AND IN THE WV MTNS...WITH HIGH CHC ACROSS THE LOWLANDS. APPEARS LLVL TEMPS WILL BE WARM ENOUGH FOR PERHAPS MAINLY RA BLO 2KFT. SYS PULLS OUT QUICKLY WED EVE FOR A RETURN TO DRY WX THU AND MOST OF FRI. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS THIS AFTERNOON WITH INCREASING SOUTHERLY FLOW. A FRONTAL BOUNDARY WILL PUSH THROUGH TONIGHT AND PROVIDE RESTRICTIONS IN LOW CLOUDS AND SHOWERS. CLOUDS WILL CLEAR FROM THE WEST MONDAY MORNING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: HIGH THIS AFTERNOON...MEDIUM WITH THE FRONT TONIGHT. ALTERNATE SCENARIOS: TIMING OF ARRIVAL OF THE RAIN AND LOWER CLOUDS TONIGHT COULD VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H H M M M M H BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY H H H H H H H H H H H M PKB CONSISTENCY H H H H H H H H H M M M CKB CONSISTENCY H H H H H H H H H H H M AFTER 18Z MONDAY... IFR POSSIBLE AGAIN WEDNESDAY AND WEDNESDAY NIGHT IN LIGHT RAIN OR SNOW...MAINLY MOUNTAIN COUNTIES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/RPY NEAR TERM...RPY SHORT TERM...TRM LONG TERM...30 AVIATION...RPY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1213 PM EST SUN FEB 10 2013 .SYNOPSIS... SOUTHERLY FLOW INCREASES TODAY. PSEUDO WARM FRONT LIFTING NORTH INTO KENTUCKY TODAY. COLD FRONT PASSES MONDAY. HIGH PRESSURE TUESDAY. LOW PRESSURE PASSES TO THE SOUTH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... WIDE RANGE OF TEMPERATURES OVERNIGHT...FROM NEAR 10 DEGREES IN THE COLDEST MOUNTAIN VALLEYS OF WEST VIRGINIA...TO NEAR 30 ALONG EXPOSED MOUNTAIN RIDGES. FIGURING ON HIGH AND MID CLOUDS THICKENING THIS MORNING...WITH SOME RADAR RETURNS FROM IT...THEN THIN OUT A BIT FOR A PERIOD THIS AFTERNOON....BEFORE THE DEEPER MOISTURE KNOCKS ON THE DOOR IN OUR WESTERN COUNTIES BY DARK. 925 MB FLOW INCREASES AT 25 TO 30 KNOTS FROM THE SSE BY 21Z. WILL INCREASE GUSTS OVER THE MOUNTAIN COUNTIES...INCLUDING SW VIRGINIA THIS AFTERNOON. WITH THE FLOW REMAINING MOSTLY SSE THIS EVENING...NOT SE...THINKING TEMPERATURES IN OUR COLDEST SPOTS IN THE UPPER GREENBRIER VALLEY WILL DROP TO AROUND 33 OR 34 DEGREES AFTER THE ONSET OF THE RAIN. SO NOT THINKING READINGS WILL DROP BELOW FREEZING. WILL INSERT A SLIGHT CHANCE OF SOME POCKETS OF FREEZING RAIN FOR ABOUT 4 HOURS CENTERED ON MIDNIGHT FOR THOSE LOCATIONS...INCLUDING PORTIONS OF POCAHONTAS AND EASTERN RANDOLPH COUNTIES. HAVE TEMPERATURES RISING DURING THE PREDAWN AS WINDS VEER TO SW THERE. NO BIG CHANGES ON POPS...WITH HOURLY POPS DECREASING QUICKLY BEFORE 12Z IN THE WESTERN LOWLANDS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... AREA GETS INTO INCREASINGLY ALIGNED WSW FLOW AS UPPER LEVEL LOW TRAVERSES GREAT LAKES MON. DEEP LAYER MOISTURE EXITS FIRST THING IN THE MORNING...AS UPPER LEVEL JET MAX PASSES. THIS WILL LEAD TO INCREASINGLY MIXED AIR MASS THAT MAY BECOME DRY ADIABATIC ALL THE WAY TO H7. HAVE WINDS REACHING CRITERIA FOR ADV ONLY FOR HIGHEST ELEVATIONS SO FAR VIA RUC MOMENTUM MIXING ALGORITHM. HIGH PRESSURE SLOWLY BUILDS IN ON TUE...ONLY TO RETREAT TUE NT AS NEXT S/W TROF APPROACHES FROM THE W. ASSOCIATED CONFLUENCE ZONE SETS UP ACROSS NRN PA AS SFC LOW TRACKS TO THE S...THE GFS/ECMWF SOLN FAVORED OVER THE NAM12...WHICH IS THE ODD MODEL N. CANADIAN IS EVEN FURTHER S. HAVE LIMITED LIKELY POPS TO FAR S PORTION OF THE AREA. WHILE THIS IS A SYNOPTICALLY CORRECT TRACK FOR SNOW...BORING PACIFIC AIR MASS IN PLACE AHEAD OF THE SYSTEM LEAVES TEMPERATURES ONLY MARGINALLY LOW ENOUGH...ESPECIALLY AT THE SFC...GIVING RISE TO MIXED PRECIPITATION AND EVEN JUST RAIN. HAVE MINIMAL SNOW AMOUNTS OF JUST OVER AN INCH ON THE CENTRAL MOUNTAINS AS SYSTEM EXITS WED AFTERNOON...AND VERY LITTLE ICE. TOGETHER WITH POPS MAINLY IN THE CHANCE RANGE...HAVE NO HWO MENTION WARRANTED AT THIS POINT AS CONFIDENCE IN CODABLE WINTER EVENT IS QUITE LOW. BLENDED IN ADJMET FOR TEMPERATURES EARLY ON...THEN ADJMAV / ADJMEX TOWARD THE END IN LIGHT OF GFS SOLN. THIS KEEPS FCST LARGELY IN LINE WITH PREVIOUS PACKAGE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... MDL TRENDS CONT TO CLOSE IN ON OP GFS SOLUTIONS AT LEAST REGARDING S/W TROF ON WED. 12Z ECWMF CONT THE TREND AS WELL. STILL SOME UNCERTAINTIES WITH SFC LOW TRACK...BUT ALL AGREE AT LEAST SOME INFLUENCE FROM INVERTED SFC TROUBLE. ELECTED TO RAISE POPS INTO LKLY ACROSS SW VA AND IN THE WV MTNS...WITH HIGH CHC ACROSS THE LOWLANDS. APPEARS LLVL TEMPS WILL BE WARM ENOUGH FOR PERHAPS MAINLY RA BLO 2KFT. SYS PULLS OUT QUICKLY WED EVE FOR A RETURN TO DRY WX THU AND MOST OF FRI. && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS THIS AFTERNOON WITH INCREASING SOUTHERLY FLOW. A FRONTAL BOUNDARY WILL PUSH THROUGH TONIGHT AND PROVIDE RESTRICTIONS IN LOW CLOUDS AND SHOWERS. CLOUDS WILL CLEAR FROM THE WEST MONDAY MORNING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: HIGH THIS AFTERNOON...MEDIUM WITH THE FRONT TONIGHT. ALTERNATE SCENARIOS: TIMING OF ARRIVAL OF THE RAIN AND LOWER CLOUDS TONIGHT COULD VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H H M M M M H BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY H H H H H H H H H H H M PKB CONSISTENCY H H H H H H H H H M M M CKB CONSISTENCY H H H H H H H H H H H M AFTER 18Z MONDAY... IFR POSSIBLE AGAIN WEDNESDAY AND WEDNESDAY NIGHT IN LIGHT RAIN OR SNOW...MAINLY MOUNTAIN COUNTIES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/TRM NEAR TERM...KTB SHORT TERM...TRM LONG TERM...30 AVIATION...RPY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
545 AM EST SUN FEB 10 2013 .SYNOPSIS... SOUTHERLY FLOW INCREASES TODAY. PSEUDO WARM FRONT LIFTING NORTH INTO KENTUCKY TODAY. COLD FRONT PASSES MONDAY. HIGH PRESSURE TUESDAY. LOW PRESSURE PASSES TO THE SOUTH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... WIDE RANGE OF TEMPERATURES OVERNIGHT...FROM NEAR 10 DEGREES IN THE COLDEST MOUNTAIN VALLEYS OF WEST VIRGINIA...TO NEAR 30 ALONG EXPOSED MOUNTAIN RIDGES. FIGURING ON HIGH AND MID CLOUDS THICKENING THIS MORNING...WITH SOME RADAR RETURNS FROM IT...THEN THIN OUT A BIT FOR A PERIOD THIS AFTERNOON....BEFORE THE DEEPER MOISTURE KNOCKS ON THE DOOR IN OUR WESTERN COUNTIES BY DARK. 925 MB FLOW INCREASES AT 25 TO 30 KNOTS FROM THE SSE BY 21Z. WILL INCREASE GUSTS OVER THE MOUNTAIN COUNTIES...INCLUDING SW VIRGINIA THIS AFTERNOON. WITH THE FLOW REMAINING MOSTLY SSE THIS EVENING...NOT SE...THINKING TEMPERATURES IN OUR COLDEST SPOTS IN THE UPPER GREENBRIER VALLEY WILL DROP TO AROUND 33 OR 34 DEGREES AFTER THE ONSET OF THE RAIN. SO NOT THINKING READINGS WILL DROP BELOW FREEZING. WILL INSERT A SLIGHT CHANCE OF SOME POCKETS OF FREEZING RAIN FOR ABOUT 4 HOURS CENTERED ON MIDNIGHT FOR THOSE LOCATIONS...INCLUDING PORTIONS OF POCAHONTAS AND EASTERN RANDOLPH COUNTIES. HAVE TEMPERATURES RISING DURING THE PREDAWN AS WINDS VEER TO SW THERE. NO BIG CHANGES ON POPS...WITH HOURLY POPS DECREASING QUICKLY BEFORE 12Z IN THE WESTERN LOWLANDS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... AREA GETS INTO INCREASINGLY ALIGNED WSW FLOW AS UPPER LEVEL LOW TRAVERSES GREAT LAKES MON. DEEP LAYER MOISTURE EXITS FIRST THING IN THE MORNING...AS UPPER LEVEL JET MAX PASSES. THIS WILL LEAD TO INCREASINGLY MIXED AIR MASS THAT MAY BECOME DRY ADIABATIC ALL THE WAY TO H7. HAVE WINDS REACHING CRITERIA FOR ADV ONLY FOR HIGHEST ELEVATIONS SO FAR VIA RUC MOMENTUM MIXING ALGORITHM. HIGH PRESSURE SLOWLY BUILDS IN ON TUE...ONLY TO RETREAT TUE NT AS NEXT S/W TROF APPROACHES FROM THE W. ASSOCIATED CONFLUENCE ZONE SETS UP ACROSS NRN PA AS SFC LOW TRACKS TO THE S...THE GFS/ECMWF SOLN FAVORED OVER THE NAM12...WHICH IS THE ODD MODEL N. CANADIAN IS EVEN FURTHER S. HAVE LIMITED LIKELY POPS TO FAR S PORTION OF THE AREA. WHILE THIS IS A SYNOPTICALLY CORRECT TRACK FOR SNOW...BORING PACIFIC AIR MASS IN PLACE AHEAD OF THE SYSTEM LEAVES TEMPERATURES ONLY MARGINALLY LOW ENOUGH...ESPECIALLY AT THE SFC...GIVING RISE TO MIXED PRECIPITATION AND EVEN JUST RAIN. HAVE MINIMAL SNOW AMOUNTS OF JUST OVER AN INCH ON THE CENTRAL MOUNTAINS AS SYSTEM EXITS WED AFTERNOON...AND VERY LITTLE ICE. TOGETHER WITH POPS MAINLY IN THE CHANCE RANGE...HAVE NO HWO MENTION WARRANTED AT THIS POINT AS CONFIDENCE IN CODABLE WINTER EVENT IS QUITE LOW. BLENDED IN ADJMET FOR TEMPERATURES EARLY ON...THEN ADJMAV / ADJMEX TOWARD THE END IN LIGHT OF GFS SOLN. THIS KEEPS FCST LARGELY IN LINE WITH PREVIOUS PACKAGE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... MDL TRENDS CONT TO CLOSE IN ON OP GFS SOLUTIONS AT LEAST REGARDING S/W TROF ON WED. 12Z ECWMF CONT THE TREND AS WELL. STILL SOME UNCERTAINTIES WITH SFC LOW TRACK...BUT ALL AGREE AT LEAST SOME INFLUENCE FROM INVERTED SFC TROUBLE. ELECTED TO RAISE POPS INTO LKLY ACROSS SW VA AND IN THE WV MTNS...WITH HIGH CHC ACROSS THE LOWLANDS. APPEARS LLVL TEMPS WILL BE WARM ENOUGH FOR PERHAPS MAINLY RA BLO 2KFT. SYS PULLS OUT QUICKLY WED EVE FOR A RETURN TO DRY WX THU AND MOST OF FRI. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... ABUNDANT HIGH AND MID CLOUDS AOA 10 THSD FT THROUGH ABOUT 22Z BEFORE THICKENING AND LOWERING. MAYBE SPRINKLES REACHING THE GROUND IN SOUTHEAST OHIO THIS MORNING. CEILINGS BECOMING 4 TO 8 THSD FT 23Z SUNDAY TO 03Z MONDAY WITH LIGHT RAIN LIMITING VSBY 3 TO 5 MILES BY 03Z TO 06Z. CEILINGS BECOMING 2 TO 3 THSD FT BY 06Z MONDAY IN WIDESPREAD RAIN...BECOMING AOB 1 THSD FT BKN OVER MOUNTAINS. A SLIGHT CHANCE OF A POCKET OF FREEZING RAIN IN POCAHONTAS COUNTY AROUND 06Z. MAIN RAIN SHIELD SHIFTING EAST..AWAY FROM THE LOWLAND COUNTIES AFTER 08Z...WITH VSBY AOA 5 MILES BUT CEILINGS REMAINING MOSTLY 2 TO 3 THSD FT BKN/OVC. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: TIMING OF ARRIVAL OF THE RAIN MAY VARY BY A COUPLE OF HOURS SUNDAY EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z MONDAY... IFR POSSIBLE AGAIN WEDNESDAY AND WEDNESDAY NIGHT IN LIGHT RAIN OR SNOW...MAINLY MOUNTAIN COUNTIES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/TRM NEAR TERM...KTB SHORT TERM...TRM LONG TERM...30 AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
426 AM EST SUN FEB 10 2013 .SYNOPSIS... SOUTHERLY FLOW INCREASES TODAY. PSEUDO WARM FRONT LIFTING NORTH THRU TENNESSEE VALLEY. COLD FRONT PASSES MONDAY. HIGH PRESSURE TUESDAY. LOW PRESSURE PASSES TO THE SOUTH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... WIDE RANGE OF TEMPERATURES OVERNIGHT...FROM NEAR 10 DEGREES IN THE COLDEST MOUNTAIN VALLEYS OF WEST VIRGINIA...TO NEAR 30 ALONG EXPOSED MOUNTAIN RIDGES. FIGURING ON HIGH AND MID CLOUDS THICKENING THIS MORNING...WITH SOME RADAR RETURNS FROM IT...THEN THIN OUT A BIT FOR A PERIOD THIS AFTERNOON....BEFORE THE DEEPER MOISTURE KNOCKS ON THE DOOR IN OUR WESTERN COUNTIES BY DARK. 925 MB FLOW INCREASES AT 25 TO 30 KNOTS FROM THE SSE BY 21Z. WILL INCREASE GUSTS OVER THE MOUNTAIN COUNTIES...INCLUDING SW VIRGINIA THIS AFTERNOON. WITH THE FLOW REMAINING MOSTLY SSE THIS EVENING...NOT SE...THINKING TEMPERATURES IN OUR COLDEST SPOTS IN THE UPPER GREENBRIER VALLEY WILL DROP TO AROUND 33 OR 34 DEGREES AFTER THE ONSET OF THE RAIN. SO NOT THINKING READINGS WILL DROP BELOW FREEZING. WILL INSERT A SLIGHT CHANCE OF SOME POCKETS OF FREEZING RAIN FOR ABOUT 4 HOURS CENTERED ON MIDNIGHT FOR THOSE LOCATIONS...INCLUDING PORTIONS OF POCAHONTAS AND EASTERN RANDOLPH COUNTIES. HAVE TEMPERATURES RISING DURING THE PREDAWN AS WINDS VEER TO SW THERE. NO BIG CHANGES ON POPS...WITH HOURLY POPS DECREASING QUICKLY BEFORE 12Z IN THE WESTERN LOWLANDS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... AREA GETS INTO INCREASINGLY ALIGNED WSW FLOW AS UPPER LEVEL LOW TRAVERSES GREAT LAKES MON. DEEP LAYER MOISTURE EXITS FIRST THING IN THE MORNING...AS UPPER LEVEL JET MAX PASSES. THIS WILL LEAD TO INCREASINGLY MIXED AIR MASS THAT MAY BECOME DRY ADIABATIC ALL THE WAY TO H7. HAVE WINDS REACHING CRITERIA FOR ADV ONLY FOR HIGHEST ELEVATIONS SO FAR VIA RUC MOMENTUM MIXING ALGORITHM. HIGH PRESSURE SLOWLY BUILDS IN ON TUE...ONLY TO RETREAT TUE NT AS NEXT S/W TROF APPROACHES FROM THE W. ASSOCIATED CONFLUENCE ZONE SETS UP ACROSS NRN PA AS SFC LOW TRACKS TO THE S...THE GFS/ECMWF SOLN FAVORED OVER THE NAM12...WHICH IS THE ODD MODEL N. CANADIAN IS EVEN FURTHER S. HAVE LIMITED LIKELY POPS TO FAR S PORTION OF THE AREA. WHILE THIS IS A SYNOPTICALLY CORRECT TRACK FOR SNOW...BORING PACIFIC AIR MASS IN PLACE AHEAD OF THE SYSTEM LEAVES TEMPERATURES ONLY MARGINALLY LOW ENOUGH...ESPECIALLY AT THE SFC...GIVING RISE TO MIXED PRECIPITATION AND EVEN JUST RAIN. HAVE MINIMAL SNOW AMOUNTS OF JUST OVER AN INCH ON THE CENTRAL MOUNTAINS AS SYSTEM EXITS WED AFTERNOON...AND VERY LITTLE ICE. TOGETHER WITH POPS MAINLY IN THE CHANCE RANGE...HAVE NO HWO MENTION WARRANTED AT THIS POINT AS CONFIDENCE IN CODABLE WINTER EVENT IS QUITE LOW. BLENDED IN ADJMET FOR TEMPERATURES EARLY ON...THEN ADJMAV / ADJMEX TOWARD THE END IN LIGHT OF GFS SOLN. THIS KEEPS FCST LARGELY IN LINE WITH PREVIOUS PACKAGE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... MDL TRENDS CONT TO CLOSE IN ON OP GFS SOLUTIONS AT LEAST REGARDING S/W TROF ON WED. 12Z ECWMF CONT THE TREND AS WELL. STILL SOME UNCERTAINTIES WITH SFC LOW TRACK...BUT ALL AGREE AT LEAST SOME INFLUENCE FROM INVERTED SFC TROUBLE. ELECTED TO RAISE POPS INTO LKLY ACROSS SW VA AND IN THE WV MTNS...WITH HIGH CHC ACROSS THE LOWLANDS. APPEARS LLVL TEMPS WILL BE WARM ENOUGH FOR PERHAPS MAINLY RA BLO 2KFT. SYS PULLS OUT QUICKLY WED EVE FOR A RETURN TO DRY WX THU AND MOST OF FRI. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... SOME LOCAL VSBY 5 TO 6 MILES IN HAZE AND SMOKE IN WV VALLEYS UNDER TEMPERATURE INVERSION OVERNIGHT. HIGH AND MID CLOUDS AOA 10 THSD FT THROUGH ABOUT 22Z BEFORE THICKENING AND LOWERING. CEILINGS BECOMING 4 TO 8 THSD FT 23Z SUNDAY TO 03Z MONDAY WITH LIGHT RAIN LIMITING VSBY 3 TO 5 MILES. CEILINGS BECOMING 2 TO 4 THSD FT BY 06Z MONDAY IN WIDESPREAD RAIN. A SLIGHT CHANCE OF A POCKET OF FREEZING RAIN IN POCAHONTAS COUNTY AROUND 06Z. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: TIMING OF ARRIVAL OF THE RAIN MAY VARY BY A COUPLE OF HOURS SUNDAY EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SUN 02/10/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z MONDAY... IFR POSSIBLE IN RAIN LATE SUNDAY NIGHT. IFR POSSIBLE AGAIN WEDNESDAY AND WEDNESDAY NIGHT IN LIGHT RAIN OR SNOW...MAINLY MOUNTAIN COUNTIES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/TRM NEAR TERM...KTB SHORT TERM...TRM LONG TERM...30 AVIATION...KTB
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1150 AM CST SUN FEB 10 2013 .UPDATE... 18Z AVIATION DISCUSSION UPDATED BELOW. ABUNDANT WAA SNOW WRAPPING INTO THE REGION LATE THIS MORNING ALONG WITH DEFORMATION ZONE INCREASING ON SATELLITE WITH COOLING TOPS. RADAR WAS ALSO IMPRESSIVE IN SHOWING NEW DEVELOPMENT FROM THE EAST THIS MORNING. THE HRRR MODEL SHOWS A GOOD AMOUNT OF PRECIPITATION CONTINUING THROUGH THE AFTERNOON. HAVE RECEIVED REPORTS OF 4 TO 11 INCHES SO FAR THIS MORNING. THUS...INCREASED SNOWFALL TOTALS FOR THE STORM WITH 5 TO 12 INCHES OR MORE WEST OF THE JAMES VALLEY WITH 8 TO 15 INCHES FROM THE JAMES VALLEY AND EAST BY THE TIME THE SNOW ENDS LATE TONIGHT INTO MONDAY MORNING. ALSO...NORTH WINDS WILL CONTINUE TO INCREASE ACROSS THE EASTERN PART OF THE REGION THIS AFTERNOON CREATING BLIZZARD CONDITIONS. ALREADY HAD REPORTS OF BLIZZARD CONDITIONS OUT WEST ALONG WITH INTERSTATE CLOSERS. && .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH TUESDAY WINTER STORM WELL UNDER WAY WITH SFC LOW STRENGTHENING OVER THE NEBRASKA/KANSAS BORDER. SNOW HAS BEEN MOVING NORTHWARD ACROSS THE REGION ALL NIGHT WITH UPPER DIFFLUENCE OVER THE REGION. FIRST BAND OF HEAVY SNOW MOVED THROUGH SEVERAL HOURS AGO AND NEXT HEAVY BAND ACROSS THE SOUTHEAST CWA MOVING NORTH-NORTHWEST. MODELS STILL SHOWING VERY IMPRESSIVE FRONTOGENESIS AND LIFT...ALONG WITH COLD AIR INSTABILITY. SNOWFALL AMOUNTS ACROSS THE AREA ARE ALREADY IN THE 3 TO 6 INCH RANGE...WITH ABR GETTING CLOSE TO 6 INCHES. WIND BEGINNING TO INCREASE ACROSS SOUTH CENTRAL SOUTH DAKOTA WITH PIR SUSTAINED AT 20 KNOTS. EVERYTHING PRETTY MUCH ON TRACK WITH THE STORM AND FORECAST WAS NOT CHANGED MUCH. STILL EXPECTING THE HEAVIEST SWATH OF SNOW FROM THE SOUTHWEST CWA NORTHEAST INTO NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA. THE SNOW SHIELD HAS MADE IT PRETTY FAR WEST ACTUALLY...WITH THE NORTHWEST CWA SEEING SNOWFALL. MBG HAS ABOUT 2 TO 3 INCHES AND STILL SNOWING WITH SELBY AROUND 4 INCHES. INCREASED SNOW TOTALS A BIT FOR NORTH CENTRAL SD. ALL IN ALL...CURRENT HEADLINES APPEAR THEY WILL WORK OUT SO NO CHANGES THERE. WINDS STILL EXPECTED TO INCREASE FROM WEST TO EAST ACROSS THE AREA TODAY...FIRST OVER CENTRAL SOUTH DAKOTA THIS MORNING WHERE SPEEDS ARE ALREADY BEGINNING TO RISE. SPEEDS WILL PICK UP IN THE JAMES VALLEY BY LATE MORNING AND EARLY AFTERNOON...THEN EVENTUALLY OVER FAR EASTERN SOUTH DAKOTA AND WEST CENTRAL MINNESOTA BY LATE AFTERNOON AND EARLY EVENING. BLOWING AND DRIFTING SNOW EXPECTED TO CAUSE SIGNIFICANT PROBLEMS ACROSS THE REGION AS WINDS COMBINE WITH FALLING SNOW AND THE SEVERAL INCHES OF SNOW ALREADY THIS MORNING. SPINK COUNTY ALREADY ADVISING NO TRAVEL AND AN LAE PRODUCT WAS SENT OUT FOR THIS SEVERAL HOURS AGO. STILL CANNOT RULE OUT THUNDERSNOW...BASICALLY OVER THE SOUTHEAST CWA WHERE BEST INSTABILITY RESIDES. ALREADY HAS SOME ISOLATED REPORTS OF THUNDERSNOW LAST NIGHT. THIS STORM STILL ON TRACK TO EXIT THE AREA ON MONDAY...BUT NOT BEFORE AN ENTIRE NIGHT OF BLOWING AND DRIFTING SNOW. WINDS WILL BEGIN TO DECREASE SLOWLY FROM WEST TO EAST ACROSS THE AREA ON MONDAY...SO STILL EXPECTING BLOWING SNOW MOST OF THE DAY ACROSS EASTERN PORTIONS OF THE FORECAST AREA. MODELS SEEM TO WANT TO END THE SNOW A TAD QUICKER ON MONDAY SO HAVE FOLLOWED SUIT IN THE FORECAST. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY NO SIGNIFICANT CHANGES MADE TO THE EXTENDED FORECAST GRIDS THIS MORNING. NORTHWEST FLOW CLIPPER SYSTEMS WILL BE THE ORDER OF THE DAY IN THE OUT PERIODS...WITH TWO OR THREE CLIPPER-TYPE SHORTWAVES WORKING SEWD THROUGH THE REGION. POPS/WX MENTION CONTINUES STARTING IN THE NORTHWEST ZONES WEDNESDAY AND SPREADING TO THE SOUTHEAST ZONES BY THURSDAY AFTERNOON/EVENING WITH THE FIRST CLIPPER WAVE. LOW LEVEL THERMAL PROGS SUGGEST WARMER LOW LEVEL AIR WILL BE WORKING INTO THE REGION TUESDAY NIGHT AND WEDNESDAY. HOWEVER...WITH ABUNDANT FRESH AND DEEP SNOW COVER OVER THE CWA...NOT ALL THAT CONFIDENT THAT TRULY WARMER TEMPERATURES WILL BE REALIZED AT THE SURFACE...PRIOR TO THE NEXT PUSH OF ARCTIC-SOURCED LOW LEVEL CAA THURSDAY INTO THURSDAY NIGHT. GFS AND ECMWF SUGGEST LOW LEVEL COLD AIR WILL STICK AROUND INTO SATURDAY. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS A STRONG SURFACE LOW PRESSURE AREA IN NORTHEAST NEBRASKA WILL HEAD NORTHEAST THROUGH TONIGHT AND BE IN THE GREAT LAKES REGION BY MONDAY MORNING. LIGHT TO HEAVY SNOWFALL AT TIMES WILL CONTINUE AT ALL TERMINALS THROUGH THIS EVENING. NORTH WINDS AT 20 TO 30 KNOTS WITH GUSTS TO 40 KNOTS ARE EXPECTED TO BRING BLIZZARD CONDITIONS AT ALL TERMINALS INTO THIS EVENING. IFR/MVFR VISIBILITIES AND CEILINGS ARE EXPECTED AT ALL LOCATIONS. THE SNOW WILL END FROM WEST TO EAST TONIGHT THROUGH MONDAY MORNING ALONG WITH DECREASING WINDS. PIR AND MBG WILL BE THE FIRST TO HAVE IMPROVEMENT WITH ABR AND ATY HAVING IMPROVEMENT LATER TONIGHT AND MONDAY MORNING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...BLIZZARD WARNING UNTIL 6 AM CST /5 AM MST/ MONDAY FOR BUFFALO- DEWEY-EDMUNDS-FAULK-HAND-HUGHES-HYDE-JONES-LYMAN-MCPHERSON- POTTER-STANLEY-SULLY-WALWORTH. BLIZZARD WARNING UNTIL NOON CST MONDAY FOR BROWN-CLARK-CODINGTON- DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS-SPINK. WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ MONDAY FOR CAMPBELL-CORSON. MN...BLIZZARD WARNING UNTIL NOON CST MONDAY FOR BIG STONE-TRAVERSE. && $$ UPDATE...MOHR SHORT TERM...TMT LONG TERM...DORN AVIATION...MOHR WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1100 AM CST SUN FEB 10 2013 .UPDATE... ABUNDANT WAA SNOW WRAPPING INTO THE REGION LATE THIS MORNING ALONG WITH DEFORMATION ZONE INCREASING ON SATELLITE WITH COOLING TOPS. RADAR WAS ALSO IMPRESSIVE IN SHOWING NEW DEVELOPMENT FROM THE EAST THIS MORNING. THE HRRR MODEL SHOWS A GOOD AMOUNT OF PRECIPITATION CONTINUING THROUGH THE AFTERNOON. HAVE RECEIVED REPORTS OF 4 TO 11 INCHES SO FAR THIS MORNING. THUS...INCREASED SNOWFALL TOTALS FOR THE STORM WITH 5 TO 12 INCHES OR MORE WEST OF THE JAMES VALLEY WITH 8 TO 15 INCHES FROM THE JAMES VALLEY AND EAST BY THE TIME THE SNOW ENDS LATE TONIGHT INTO MONDAY MORNING. ALSO...NORTH WINDS WILL CONTINUE TO INCREASE ACROSS THE EASTERN PART OF THE REGION THIS AFTERNOON CREATING BLIZZARD CONDITIONS. ALREADY HAD REPORTS OF BLIZZARD CONDITIONS OUT WEST ALONG WITH INTERSTATE CLOSERS. && .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH TUESDAY WINTER STORM WELL UNDER WAY WITH SFC LOW STRENGTHENING OVER THE NEBRASKA/KANSAS BORDER. SNOW HAS BEEN MOVING NORTHWARD ACROSS THE REGION ALL NIGHT WITH UPPER DIFFLUENCE OVER THE REGION. FIRST BAND OF HEAVY SNOW MOVED THROUGH SEVERAL HOURS AGO AND NEXT HEAVY BAND ACROSS THE SOUTHEAST CWA MOVING NORTH-NORTHWEST. MODELS STILL SHOWING VERY IMPRESSIVE FRONTOGENESIS AND LIFT...ALONG WITH COLD AIR INSTABILITY. SNOWFALL AMOUNTS ACROSS THE AREA ARE ALREADY IN THE 3 TO 6 INCH RANGE...WITH ABR GETTING CLOSE TO 6 INCHES. WIND BEGINNING TO INCREASE ACROSS SOUTH CENTRAL SOUTH DAKOTA WITH PIR SUSTAINED AT 20 KNOTS. EVERYTHING PRETTY MUCH ON TRACK WITH THE STORM AND FORECAST WAS NOT CHANGED MUCH. STILL EXPECTING THE HEAVIEST SWATH OF SNOW FROM THE SOUTHWEST CWA NORTHEAST INTO NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA. THE SNOW SHIELD HAS MADE IT PRETTY FAR WEST ACTUALLY...WITH THE NORTHWEST CWA SEEING SNOWFALL. MBG HAS ABOUT 2 TO 3 INCHES AND STILL SNOWING WITH SELBY AROUND 4 INCHES. INCREASED SNOW TOTALS A BIT FOR NORTH CENTRAL SD. ALL IN ALL...CURRENT HEADLINES APPEAR THEY WILL WORK OUT SO NO CHANGES THERE. WINDS STILL EXPECTED TO INCREASE FROM WEST TO EAST ACROSS THE AREA TODAY...FIRST OVER CENTRAL SOUTH DAKOTA THIS MORNING WHERE SPEEDS ARE ALREADY BEGINNING TO RISE. SPEEDS WILL PICK UP IN THE JAMES VALLEY BY LATE MORNING AND EARLY AFTERNOON...THEN EVENTUALLY OVER FAR EASTERN SOUTH DAKOTA AND WEST CENTRAL MINNESOTA BY LATE AFTERNOON AND EARLY EVENING. BLOWING AND DRIFTING SNOW EXPECTED TO CAUSE SIGNIFICANT PROBLEMS ACROSS THE REGION AS WINDS COMBINE WITH FALLING SNOW AND THE SEVERAL INCHES OF SNOW ALREADY THIS MORNING. SPINK COUNTY ALREADY ADVISING NO TRAVEL AND AN LAE PRODUCT WAS SENT OUT FOR THIS SEVERAL HOURS AGO. STILL CANNOT RULE OUT THUNDERSNOW...BASICALLY OVER THE SOUTHEAST CWA WHERE BEST INSTABILITY RESIDES. ALREADY HAS SOME ISOLATED REPORTS OF THUNDERSNOW LAST NIGHT. THIS STORM STILL ON TRACK TO EXIT THE AREA ON MONDAY...BUT NOT BEFORE AN ENTIRE NIGHT OF BLOWING AND DRIFTING SNOW. WINDS WILL BEGIN TO DECREASE SLOWLY FROM WEST TO EAST ACROSS THE AREA ON MONDAY...SO STILL EXPECTING BLOWING SNOW MOST OF THE DAY ACROSS EASTERN PORTIONS OF THE FORECAST AREA. MODELS SEEM TO WANT TO END THE SNOW A TAD QUICKER ON MONDAY SO HAVE FOLLOWED SUIT IN THE FORECAST. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY NO SIGNIFICANT CHANGES MADE TO THE EXTENDED FORECAST GRIDS THIS MORNING. NORTHWEST FLOW CLIPPER SYSTEMS WILL BE THE ORDER OF THE DAY IN THE OUT PERIODS...WITH TWO OR THREE CLIPPER-TYPE SHORTWAVES WORKING SEWD THROUGH THE REGION. POPS/WX MENTION CONTINUES STARTING IN THE NORTHWEST ZONES WEDNESDAY AND SPREADING TO THE SOUTHEAST ZONES BY THURSDAY AFTERNOON/EVENING WITH THE FIRST CLIPPER WAVE. LOW LEVEL THERMAL PROGS SUGGEST WARMER LOW LEVEL AIR WILL BE WORKING INTO THE REGION TUESDAY NIGHT AND WEDNESDAY. HOWEVER...WITH ABUNDANT FRESH AND DEEP SNOW COVER OVER THE CWA...NOT ALL THAT CONFIDENT THAT TRULY WARMER TEMPERATURES WILL BE REALIZED AT THE SURFACE...PRIOR TO THE NEXT PUSH OF ARCTIC-SOURCED LOW LEVEL CAA THURSDAY INTO THURSDAY NIGHT. GFS AND ECMWF SUGGEST LOW LEVEL COLD AIR WILL STICK AROUND INTO SATURDAY. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS A POTENT WINTER STORM HAS DESCENDED UPON CENTRAL AND NORTHEAST SOUTH DAKOTA THIS MORNING...RESULTING IN ALL VARIETIES OF IFR CONDITION IN FALLING AND BLOWING SNOW. VERY POOR FLYING CONDITIONS IN MODERATE TO HEAVY SNOW WILL PERSIST FOR MUCH OF THE DAY TODAY INTO THIS EVENING OVER THE KABR AND KATY TERMINALS. BY EARLY THIS EVENING...BLIZZARD CONDITIONS SHOULD BE COMMENCING AT THESE TWO TERMINALS AS WELL...WITH SUSTAINED NORTHWEST WINDS OF 25 TO 35 MPH WITH GUSTS TO 45 MPH...PERSISTING RIGHT ON THROUGH TONIGHT INTO MONDAY MORNING. THE KPIR AND KMBG TERMINALS WILL CONTINUE TO SEE LIGHT TO MODERATE SNOW THROUGHOUT THE DAY TODAY. THE BLIZZARD CONDITIONS KICK IN BY MID MORNING AT THESE TWO TERMINALS...WITH SUSTAINED NORTHWEST WINDS OF 20 TO 40 MPH WITH GUSTS AS HIGH AS 50 MPH...PERSISTING THROUGH TONIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...BLIZZARD WARNING UNTIL 6 AM CST /5 AM MST/ MONDAY FOR BUFFALO- DEWEY-EDMUNDS-FAULK-HAND-HUGHES-HYDE-JONES-LYMAN-MCPHERSON- POTTER-STANLEY-SULLY-WALWORTH. BLIZZARD WARNING UNTIL NOON CST MONDAY FOR BROWN-CLARK-CODINGTON- DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS-SPINK. WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ MONDAY FOR CAMPBELL-CORSON. MN...BLIZZARD WARNING UNTIL NOON CST MONDAY FOR BIG STONE-TRAVERSE. && $$ UPDATE...MOHR SHORT TERM...TMT LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
954 PM CST MON FEB 11 2013 .UPDATE... HAVE MADE A FEW CHANGES TO GOING FORECAST AS RECENT MODEL TRENDS HAVE TRENDED EARLIER...COLDER...AND A BIT HEAVIER WITH THE IMPENDING SNOW. SNOW HAS ALREADY SPREAD INTO THE WESTERN TEXAS PANHANDLE...WITH TEXLINE REPORTING MODERATE SNOW. TIMING... HAVE SHIFTED ALMOST ALL AREAS FORWARD ABOUT 3 HOURS FOR THE ONSET OF SNOW GIVEN RECENT HRRR AND NAM RUNS. THIS BRINGS TOTALS UP TO 1-3 INCHES SW OF A CANADIAN TO GUYMON LINE BEFORE THE MORNING COMMUTE. THE I40 CORRIDOR EAST OF AMARILLO WILL LIKELY SEE THE HEAVIEST SNOWS BEFORE 12Z AND THROUGHOUT THE EVENT. HAVE ALSO BROUGHT THE SNOW TO AN END QUICKER...WITH ALL SNOWS LIKELY EAST OF THE PANHANDLES BY 00Z. AMOUNTS... THE MAIN CHANGE WAS TO INCREASE AMOUNTS IN AN AREA BOUNDED BY ROUGHLY I27 ON THE WEST AND I40 ON THE NORTH. IT PREVIOUSLY APPEARED THAT THE DAYTIME TIMING AND SUBSEQUENT LOWER SNOW TO LIQUID RATIOS WOULD KEEP TOTALS DOWN A BIT IN THESE AREAS. HOWEVER...THE BULK OF THE SNOW NOW LOOKS TO FALL BETWEEN 09Z-15Z...MEANING THAT RATIOS WILL LIKELY BE HIGHER AND AMOUNTS GREATER. GIVEN SOME LIKELY MODEL UNDERESTIMATION OF DYNAMIC COOLING IN THESE AREAS...FELT A BUMP UP IN TOTALS PRUDENT. CURRENT THINKING IS THAT THE AMARILLO AREA COULD SEE 4-7 INCHES...WITH HIGHER AMOUNTS FURTHER EAST. GIVEN RECENT MODEL TRENDS...AM A BIT CONCERNED WE COULD END UP SEEING AN ISOLATED BIG NUMBER IN THE DOUBLE DIGITS SOMEWHERE IN THE ROBERTS/GRAY/ HEMPHILL/WHEELER COUNTY AREA. UPDATED GRIDS/ZONES WILL BE OUT VERY SOON. SIMPSON && .PREV DISCUSSION... /ISSUED 543 PM CST MON FEB 11 2013/ AVIATION... FOR THE 00Z KAMA TAF...VFR CONDITIONS ARE EXPECTED THROUGH 06Z...THEN A WINTER STORM LEADS TO A MORE COMPLICATED AND LOWER CONFIDENCE FORECAST AFTER 06Z THROUGH THE END OF THE TAF PERIOD. HIGH CONFIDENCE THAT THE TERMINAL WILL SEE SN...PRIMARILY BETWEEN 09 AND 18Z...AND IFR OR LOWER CONDITIONS THROUGH THIS TIME. THOUGH WINDS WILL BE BREEZY BETWEEN 12 AND 18Z...DO NOT EXPECT TOO MUCH BLSN DUE TO THE SNOW TO LIQUID RATIO BEING A BIT LOW. SN WILL SLOWLY TAPER OFF AFTER 18Z...AND SHOULD BE OUT OF THE AREA BY 21Z. CONDITIONS SHOULD IMPROVE TO VFR ONCE THE SN ENDS. FOR THE 00Z KDHT AND KGUY TAFS...VFR CONDITIONS ARE LIKELY THROUGH 06Z...WITH THE ONLY POSSIBLE EXCEPTION OF LIGHT SN STARTING IN KDHT POSSIBLY AS EARLY AS 03Z. AFTER 06Z...THERE IS LOWER CONFIDENCE GIVEN THE INCOMING WINTER STORM. AT THIS POINT...EXPECT SN TO START IN KDHT LIKELY AROUND 06Z...AND KGUY BETWEEN 09 AND 12Z. FOR THE MOST PART THROUGH THIS EVENT...EXPECT LOW MVFR OR IFR CONDITIONS. SN AT THESE 2 TERMINALS IS NOT EXPECTED TO BE AS DEEP OR HEAVY AS KAMA. SN SHOULD BEGIN TO TAPER OFF NEAR 18Z...AND SHOULD BE OUT OF THE AREA BY 21Z. ONCE THE SN ENDS...EXPECT VFR CONDITIONS THROUGH THE REMAINDER OF THE TAF PERIOD. JOHNSON PREV DISCUSSION... /ISSUED 400 PM CST MON FEB 11 2013/ DISCUSSION... THROUGH TONIGHT: UPPER TROUGH MOVING ACROSS THE FOUR CORNERS WILL DEEPEN AS IT APPROACHES THE PANHANDLES TONIGHT. AHEAD OF THIS UPPER TROUGH, EASTERLY UPSLOPE WINDS AND ISENTROPIC LIFT WILL INCREASE MOISTURE SUBSTANTIALLY AS THE NIGHT PROGRESSES. THE COMBINATION OF THE LOW- AND UPPER-LEVEL LIFT AND MOISTURE SHOULD TRIGGER THE DEVELOPMENT OF PRECIPITATION ACROSS NORTHEAST NEW MEXICO LATER THIS EVENING AND THEN SPREAD INTO THE NORTHWEST PANHANDLES AFTER 9 PM. AS TEMPERATURES COOL, THIS PRECIPITATION IS EXPECTED TO FALL AS SNOW, ROUGHLY WEST OF A GUYMON TO BOOTLEG LINE THROUGH MIDNIGHT. SOME LIGHT ACCUMULATIONS OF AROUND ONE HALF OF AN INCH WILL BE POSSIBLE ACROSS THE WESTERN PORTIONS OF CIMARRON AND DALLAM COUNTIES. AFTER MIDNIGHT, CHANCES FOR PRECIPITATION WILL INCREASE AND CONTINUE ACROSS THE NORTHWEST. A SECOND, MORE CONCENTRATED, SWATCH OF PRECIPITATION IS EXPECTED TO SPREAD NORTHWARD INTO THE SOUTHEASTERN TEXAS PANHANDLE AFTER 3 AM. FORECAST SOUNDINGS AFTER 3 AM WILL BE SUPPORTIVE OF WET SNOW ACROSS MOST OF THESE AREAS. HOWEVER, FOR LOCATIONS SOUTH AND EAST OF A LINE FROM CLARENDON TO SHAMROCK, WET BULB ZERO HEIGHTS WILL REMAIN ABOVE 2,000 FEET...WHICH WILL KEEP THE PRECIPITATION TYPE AS RAIN. AS THE COLUMN COOLS TOWARDS SUNRISE, THE RAIN IS EXPECTED TO TRANSITION TO SNOW IN THESE LOCATIONS. IN BETWEEN THESE TWO AREAS, INCLUDING AMARILLO, BORGER, AND PERRYTON, THERE MAY NOT BE MUCH IN THE WAY OF PRECIPITATION OVERNIGHT. HOWEVER, WE KEPT A MENTION OF SNOW IN THE FORECAST, BUT AMOUNTS IN THESE LOCATIONS WILL BE A DUSTING TO ONE HALF OF AN INCH AT MOST. TUESDAY-TUESDAY NIGHT: THE BEST COMBINATION OF DYNAMICS AND MOISTURE WILL OCCUR DURING THE DAY ON TUESDAY. AS THIS OCCURS, SNOW IS EXPECTED TO DEVELOP ACROSS ALL OF THE PANHANDLES WITH THE HIGHEST CHANCES BEING SOUTHEAST OF A GUYMON TO HEREFORD LINE. DUE TO STRONG DYNAMICS IN PLACE, SOME OF THE SNOW COULD BE HEAVY AT TIMES. THE TIME FRAME FOR THE HEAVIEST SNOW LOOKS TO BE BETWEEN 8 AM AND 3 PM. MOISTURE WILL BE LOWEST ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE PANHANDLES. AS A RESULT, THESE LOCATIONS WILL LIKELY SEE THE LIGHTEST SNOWFALL ACCUMULATIONS, BUT TOTAL SNOWFALL AMOUNTS WILL STILL BE BETWEEN 2 AND 5 INCHES WITH LOCALLY HIGHER AMOUNTS UP TO 6 INCHES. DEEPER MOISTURE WILL BE CONFINED TO THE SOUTHEAST THIRD OF THE PANHANDLES WHERE TOTAL SNOWFALL ACCUMULATIONS WILL BE BETWEEN 6 AND 9 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THE HEAVIEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR IN AN AREA EAST OF A LINE FROM CANADIAN TO PAMPA TO CLAUDE AND GENERALLY NORTH OF INTERSTATE 40. IT`S NOT OUT OF THE QUESTION SOME LOCATION IN THIS AREA COULD RECEIVE AS MUCH AS 10 INCHES OF SNOW. WE DO HAVE SOME CONCERN THAT MODELS HAVE BEGUN TRENDING SLIGHTLY FARTHER NORTH WITH THE UPPER TROUGH. THIS COULD SIGNIFICANTLY REDUCE THE SNOW AMOUNTS IN THE SOUTHERN PART OF THE TEXAS PANHANDLE AND SHIFT THE HIGHER TOTALS FARTHER NORTH. WE`LL NEED TO WATCH THIS CLOSELY IN CASE THE WINTER STORM WARNING NEEDS TO BE ADJUSTED. WE HAVE HIGH CONFIDENCE THAT EVERY LOCATION WILL SEE AT LEAST SOME SNOW OVER THE NEXT 24 HOURS, AND THIS IS SUPPORTED BY THE CIPS ANALOG GUIDANCE. THE SNOW IS EXPECTED TO BEGIN TAPERING OFF FROM NORTHWEST TO SOUTHEAST BY LATE TUESDAY AFTERNOON. THERE IS A POSSIBILITY THAT TEMPERATURES WILL RISE ABOVE FREEZING DURING THE AFTERNOON ACROSS MOST OF THE AREA, ESPECIALLY ACROSS THE NORTHWEST HALF OF THE PANHANDLES AND THE FAR SOUTHEASTERN TEXAS PANHANDLE. THIS WILL LIKELY HELP LIMIT/SIGNIFICANTLY CUT DOWN ON ADDITIONAL SNOWFALL ACCUMULATIONS. TUESDAY EVENING, SNOW IS EXPECTED TO CONTINUE EAST OF A BEAVER TO CLAUDE LINE THROUGH TUESDAY EVENING BEFORE ENDING BY MIDNIGHT. LOW TEMPERATURES IN THE TEENS TO LOWER 20S WILL BE LIKELY DUE TO LIGHT WINDS, CLEAR SKIES, AND SNOW COVER. JACKSON WEDNESDAY-MONDAY: AN UPPER TROUGH WILL MOVE EAST OF THE PANHANDLES WEDNESDAY WITH A DRY NORTHWESTERLY UPPER FLOW ACROSS THE PANHANDLES WEDNESDAY AND THURSDAY. A NORTHERN STREAM SHORTWAVE TROUGH WILL DROP SOUTHEAST OUT OF THE ROCKIES BY LATE THURSDAY AND ALLOW FOR A STRONG COLD FRONT TO PUSH THROUGH THE FORECAST AREA WEDNESDAY NIGHT AND THURSDAY MORNING. SCATTERED RAIN OR SNOW SHOWERS ARE EXPECTED TO PUSH SOUTH AND EAST ACROSS THE NORTHERN SECTIONS OF THE PANHANDLES THURSDAY NIGHT...AND THEN ACROSS MUCH OF THE PANHANDLES FRIDAY. SNOW COVER WEDNESDAY AND POSSIBLY EVEN INTO THURSDAY WILL HOLD TEMPERATURES DOWN...SO UNDERCUT MOS GUIDANCE. COLDER FRIDAY AND TEMPERATURES SATURDAY WILL DEPEND ON ANY SNOW COVER FROM THE THURSDAY NIGHT AND FRIDAY SYSTEM. OTHERWISE...MODERATING CONDITIONS LATE THIS WEEK AND INTO THE WEEKEND AS HIGH PRESSURE PREVAILS WITH A DRY NORTHWESTERLY FLOW ALOFT. SCHNEIDER FIRE WEATHER... AN UPPER TROUGH WILL APPROACH THE TEXAS AND OKLAHOMA PANHANDLES TONIGHT AND TUESDAY BRINGING INCREASING CHANCES FOR SNOW. ALTHOUGH THE SNOW IS EXPECTED TO END BY TUESDAY EVENING AS THE UPPER TROUGH MOVES OFF TO THE EAST OF THE PANHANDLES...THE SNOW COVER WILL LINGER THROUGH WEDNESDAY. THEREFORE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH WEDNESDAY. SCHNEIDER && .AMA WATCHES/WARNINGS/ADVISORIES... TX...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH... HANSFORD...HARTLEY...MOORE...OCHILTREE...OLDHAM...SHERMAN. WINTER STORM WARNING FROM 3 AM TO 9 PM CST TUESDAY FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH... DONLEY...GRAY...HEMPHILL...HUTCHINSON...LIPSCOMB...POTTER... RANDALL...ROBERTS...WHEELER. OK...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS. && $$ 16/09
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
400 PM CST SUN FEB 10 2013 .DISCUSSION... THE COLD FRONT HAS PUSHED OFFSHORE THIS AFTERNOON WITH TEMPERATURES IN THE MID 60S ACROSS SOUTHEAST TEXAS. SKIES WILL REMAIN CLOUDY OVERNIGHT AS SOUTHWESTERLY FLOW ALOFT WILL KEEP PACIFIC MOISTURE STREAMING ACROSS THE REGION. OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S AND LOWER 50S ACROSS OUR INLAND COUNTIES TONIGHT WITH LOWS ALONG THE COAST IN THE LOW 60S. RAIN WILL REMAIN IN THE FORECAST THROUGH EARLY WEDNESDAY. ISENTROPIC ASCENT ACROSS THE REGION ON MONDAY WILL ALLOW FOR LIGHT SHOWERS THROUGHOUT THE DAY WHILE ANOTHER UPPER LEVEL DISTURBANCE APPROACHES THE REGION ON TUESDAY. THIS SYSTEM WILL PRODUCE HIGHER RAIN CHANCES ACROSS THE REGION BEFORE MUCH COOLER AND DRIER AIR FILTERS INTO THE REGION ON WEDNESDAY. THIS COOLER AIR WILL BE REINFORCED BY ANOTHER FRONTAL PASSAGE ON FRIDAY LEADING TO DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES FOR THE LATTER HALF OF THE WEEK. 38 && .MARINE... NORTHERLY FLOW IN THE WAKE OF THE COLD FRONT SPREADING SOUTHWARD...A LITTLE FASTER SOUTH OF MATAGORDA BAY. RAP HAS BEEN HANDLING WINDS WELL WITH THE 18Z RUN. MIGHT BRIEFLY FLIRT WITH SCEC CONDITIONS SOUTH OF MATAGORDA BAY TONIGHT. GRADIENT RESPONDS BY INCREASING AND BECOMING NORTHEASTERLY AS HIGH PRESSURE BUILDS OVER ARKLATEX- MISSISSIPPI AREA TONIGHT AND MONDAY. SCEC CONDITIONS LOOK MORE LIKELY ON MONDAY. SHOWERS TONIGHT ALONG THE FRONTAL BOUNDARY THEN AS S/W MOVING THROUGH TEXAS ON MONDAY EXPECT TO SEE SOME -RA/SHRA OVER THE UPPER TEXAS COASTAL WATERS MAINLY EARLY MONDAY THROUGH EARLY AFTERNOON. ANOTHER PACIFIC COLD FRONT MOVES OFF THE COAST TUESDAY NIGHT BRINGING SCEC CONDITIONS. TIDES STILL .5 TO 1.5 FEET ABOVE NORMAL AND THIS SHOULD CONTINUE THROUGH TUESDAY NIGHT THEN FALL BACK TOWARD NORMAL WITH THE NW FLOW. 45 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 54 63 53 67 43 / 20 30 30 50 10 HOUSTON (IAH) 58 68 55 68 48 / 20 30 30 50 10 GALVESTON (GLS) 62 67 60 68 60 / 30 30 30 40 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...38 AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
349 PM CST SUN FEB 10 2013 .SHORT TERM... RELATIVELY QUIET WEATHER CONDITIONS IN THE SHORT TERM PERIOD. A WEAK FRONT WILL ENTER THE BIG COUNTRY LATE TONIGHT BUT WILL WASH OUT ACROSS THE AREA ON MONDAY. SUBTROPICAL JET WILL CONTINUE TO FEED MID AND HIGH LEVEL MOISTURE FROM THE SOUTHWEST ACROSS MAINLY SOUTHERN SECTIONS OVERNIGHT. THE NAM CONTINUES TO SHOW SOME LIGHT RAIN SHOWERS DEVELOPING OVER EXTREME SOUTHEAST COUNTIES ON MONDAY IN AN AREA OF WEAK ISENTROPIC ASCENT/WAA. 3KM WRF AND LATEST RUC ALSO HINTING AT THIS POSSIBILITY SO WILL KEEP SLIGHT CHANCE POPS INTACT THIS FORECAST CYCLE. CLOUD COVER WILL LIMIT COOLING ACROSS SOUTHEAST SECTIONS TONIGHT WITH LOWS MAINLY IN THE LOWER 40S. LIMITED CLOUD COVER...LIGHT WINDS AND A DRY AIRMASS WILL ALLOW TEMPS TO COOL INTO THE LOW TO MID 30S ACROSS THE REMAINDER OF THE AREA. MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE ON MONDAY WITH AFTERNOON HIGHS RANGING FROM THE LOW TO MID 60S NORTH TO THE MID AND UPPER 60S SOUTH. .LONG TERM... UPPER LOW NEAR THE FOUR CORNERS LATE MONDAY WILL WILL DIG SOUTHEAST TUESDAY INTO NEW MEXICO. SURFACE TO 850MB LAYER WILL QUICKLY SATURATE OVER THE ENTIRE CWA BY MIDNIGHT MONDAY CONCOMITANT WITH AN INTENSIFYING LLJ...40-50KT CENTERED OVER THE SOUTHWESTERN CWA. THE HEAVIEST RAINFALL ACCUMULATION CHANCES WILL BE OVER THE BIG COUNTRY ON THE NOSE OF THE LOW LEVEL JET BEGINNING AROUND MIDNIGHT MONDAY AND LASTING INTO TUESDAY MORNING. HAVE INCLUDED THE MENTION OF CONVECTIVE ACTIVITY MONDAY NIGHT THROUGH TUESDAY AS THE COLD FRONT/DRYLINE MOVES EAST THROUGH THE FORECAST AREA. LATEST SPC CONVECTIVE OUTLOOK MENTIONS VIA A SEE TEXT THE POSSIBILITY FOR LARGE HAIL FOR OUR AREA BASED ON SUFFICIENT INSTABILITY AND SHEAR VALUES FOR ELEVATED SUPERCELLS...AS REFLECTED IN THE LATEST FORECAST SOUNDINGS...WILL CONTINUE TO EVALUATE THIS POSSIBILITY. PRECIPITATION CHANCES WILL BE CONFINED TO OUR EASTERN TIER OF COUNTIES BY TUESDAY AFTERNOON WITH PRECIPITATION ENDING OVER ALL OF THE FORECAST AREA BY TUESDAY EVENING. TUESDAY MORNING LOWS WILL RANGE FROM THE LOWER 40S TO AROUND 50 DEGREES AND TUESDAY AFTERNOON HIGHS WILL RANGE FROM THE MID 50S TO THE MID 60S UNDER CLOUDY SKIES. AFTERNOON HIGHS AND MORNING LOWS WILL REMAIN NEAR CLIMO THROUGH THE COMING WEEKEND...GENERALLY IN THE LOWER 60S FOR HIGHS AND THE MID 30S FOR LOWS. THE NEXT COLD FRONTAL PASSAGE WILL BE LATE THURSDAY WITH LITTLE IMPACT ON THE FORECAST AREA. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 34 64 46 58 32 / 0 5 60 40 10 SAN ANGELO 32 70 50 64 35 / 0 10 50 10 5 JUNCTION 38 68 45 66 35 / 0 20 50 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 24/15
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1140 PM CST SAT FEB 9 2013 .AVIATION... BREEZY WEST WINDS WILL CONTINUE OVERNIGHT. THE WINDS WILL INCREASE SUNDAY MORNING AS STRONGER WINDS ALOFT MIX DOWNWARD. SOME LIGHT BLOWING DUST IS EXPECTED AGAIN AT KLBB...BUT VSBYS SHOULD REMAIN ABOVE MVFR. THE WINDS WILL BEGIN TO DECREASE LATE SUNDAY AFTERNOON AS THE GRADIENT RELAXES. A FRONT WILL APPROACH KCDS AFTER 0Z. && .PREV DISCUSSION... /ISSUED 1001 PM CST SAT FEB 9 2013/ UPDATE... HAVE DONE A QUICK UPDATE TO CLEAN UP THE GRIDS AND TRIM BACK POPS. SEVERE CONVECTION HAS QUICKLY COME TO AN END...THOUGH WE COULD STILL SEE A FEW SHOWERS OR STORMS YET OVER THE NEXT HOUR OR TWO ACROSS THE FAR EASTERN ZONES BEFORE THE PACIFIC FRONT CLEARS THE AREA. OTHERWISE...DRY AND BREEZY CONDITIONS WILL BE THE RULE BEHIND THE FRONT OVERNIGHT. PREV DISCUSSION... /ISSUED 821 PM CST SAT FEB 9 2013/ UPDATE... WE HAVE ALLOWED THE WIND ADVISORY AND WARNING TO EXPIRE ON SCHEDULE AT 8 PM. WINDS...IN GENERAL...ARE COMING DOWN...THOUGH A FEW SPOTS IMMEDIATELY BEHIND THE ADVANCING PACIFIC FRONT MAY BRIEFLY TOUCH ADVISORY LEVELS. OTHER CONCERN WILL CONTINUE TO REVOLVE AROUND DEVELOPING CONVECTION THAT IS FORMING ACROSS THE NORTHEAST ZONES CURRENTLY. THIS CONVECTION IS OCCURRING IN A WEAKLY UNSTABLE AIRMASS...BUT IS SUPPORTED BY INCREASING LARGE SCALE ASCENT AND INCREASED LOW-LEVEL FORCING AS A PACIFIC FRONT IS IMPINGING ON THE IMPROVED LOW-LEVEL MOISTURE RESIDING ACROSS ROUGHLY THE EASTERN HALF OF THE CWA. COULD YET SEE A FEW STRONG/SEVERE STORMS...LIKELY FAVORING THE NORTHEAST ZONES. IT BECOMES MORE UNCERTAIN HOW FAR SOUTH THE CONVECTION CAN DEVELOP INTO THE ROLLING PLAINS AS LOW-LEVEL CONVERGENCE IS PROGGED TO WEAKEN WITH SOUTHERN EXTENT AND CIN INCREASE. REGARDLESS...CONVECTION WILL QUICKLY SHIFT EAST...AND LIKELY BE OUT OF THE CWA BY MIDNIGHT. PREV DISCUSSION... /ISSUED 540 PM CST SAT FEB 9 2013/ AVIATION... GUSTY STRONG WINDS WILL BE THE MAIN CONCERN AT BOTH TERMINALS THROUGH 1 OR 2Z...AFTER WHICH THE WINDS SHOULD DECREASE TO LESS THAN ABOUT 18 KTS SUSTAINED. SOME LIGHT BLOWING DUST IS EXPECTED AT KLBB THROUGH 1Z. ALSO...THERE IS A CHANCE OF TSRA IN THE VICINITY OF KCDS THROUGH ABOUT 4Z. A FRONT WILL MOVE EAST ACROSS THE AREA BEFORE MIDNIGHT BRINGING A WIND SHIFT FROM SW TO WEST BUT WITH NOT MUCH CHANGE IN WIND SPEED GIVEN THE TIME OF DAY. SUNDAY MORNING...THE WINDS WILL RAMP UP AGAIN AS STRONG W-NW WINDS ALOFT MIX DOWN. SOME LIGHT BLOWING DUST WILL BE POSSIBLE AT LUBBOCK AGAIN BY MIDDAY. THE WINDS WILL START TO DIMINISH SUNDAY AFTERNOON. PREV DISCUSSION... /ISSUED 304 PM CST SAT FEB 9 2013/ SHORT TERM... A BUSY AFTERNOON IS IN STORE FOR THE CWA... WITH BOTH HIGH WINDS IN THE WEST AND THE POSSIBILITY FOR STORMS IN THE EAST. AS EXPECTED... A POTENT TROUGH IS CURRENTLY ADVANCING ON WEST TEXAS... WITH A 500MB KT MAX OF OVER 100KT CURRENTLY SITUATED OVER EASTERN NEW MEXICO. HIGH CLOUDS HAVE CLEARED OVER MOST OF THE NW PORTION OF THE CWA AND NEW MEXICO...ALLOWING FOR DEEP MIXING AND VERY STRONG WINDS ACROSS MOST OF EASTERN NEW MEXICO. WINDS HAVE BEEN SLOW TO VEER IN WEST TEXAS THIS AFTERNOON...ALLOWING DEWPOINTS TO CLIMB INTO THE UPPER 30S AND NEAR 40 ACROSS MOST OF THE CAPROCK AS OF 18Z. HOWEVER... SURFACE OBS AND RADAR TRENDS ARE INDICATING THAT WINDS ARE FINALLY BEGINNING TO VEER SLIGHTLY IN THE WEST... WHICH HAS RESULTED IN RAPID DRYING AND INCREASING WIND SPEEDS JUST EAST OF THE TEXAS NEW MEXICO BORDER. GIVEN THESE TRENDS... HAVE OPTED TO UPGRADE PARMER...CASTRO AND BAILEY COUNTIES TO A HIGH WIND WARNING THROUGH 02Z. FIRE WEATHER CONCERNS ARE STILL MINIMAL... ESPECIALLY GIVEN THE HIGHER THAN ANTICIPATED DEWPOINTS ACROSS THE WEST AND MOIST FUEL CONDITIONS... HOWEVER ELEVATED FIRE WEATHER CONDITIONS AND SOME RED FLAG MINUTES WILL BE PRESENT NEAR THE TX/NM BORDER THROUGH THE EARLY EVENING WHERE THE AIR WILL BE DRIEST AND WINDS STRONGEST. FURTHER EAST... THE FORECAST STILL APPEARS TO BE LARGELY ON TRACK AS MOISTURE CONTINUES TO RETURN ACROSS THE EAST. RADAR AND SURFACES OBSERVATIONS INDICATE THE BEGINNINGS OF A DRYLINE FORMING JUST TO THE EAST OF THE TX/NM STATE LINE...AND APPEARS TO BE SLOWLY ADVANCING EAST. IN ADDITION... VISIBLE SATELLITE IMAGERY IS SHOWING AN INCREASE IN CUMULIFORM CLOUDS JUST TO THE DRY SIDE OF THIS DEVELOPING DRYLINE. DEWPOINTS AS OF 20Z HAVE REACHED THE UPPER 40S ACROSS THE SOUTHEAST...TO NEAR 40 IN THE NORTHERN ROLLING PLAINS...WHICH IS A BIT LOWER THAN YOU WOULD LIKE FOR STORM DEVELOPMENT. AS SUCH... INSTABILITY IS STILL VERY WEAK ACROSS THE AREA...WITH MAXIMUM VALUES OF NEAR 500 J/KG RESTRICTED TO THE SOUTHEAST. THERE STILL REMAINS SOME TIME FOR MOISTURE TO INCREASE...AND IT STILL SEEMS WITHIN REASON THAT DEWPOINTS WILL REACH THE UPPER 40S TO LOW 50S WITHIN THE NEXT FEW HOURS. LOCAL HIGH RESOLUTION MODELS...INCLUDING THE TTUWRF AND TO A LESSER EXTENT THE HRRR... SEEM TO BE SUGGESTING THAT INITIATION MAY HOLD OFF UNTIL 00Z... HOWEVER THE RUC IS STILL FIRING AROUND 22Z. GIVEN CURRENT TRENDS... IT SEEMS THAT THE LATER INITIATION SOLUTIONS SEEM MORE PLAUSIBLE. GIVEN THE VERY STRONGLY SHEARED WIND FIELDS... ANY STORMS THAT CAN MANAGE TO INITIATE EARLY WILL VERY LIKELY BE SUPERCELLULAR... AND COULD POSE A VERY ISOLATED TORNADO THREAT IF MOISTURE CAN CONTINUE TO RISE. HOWEVER...THIS THREAT APPEARS TO BE VERY MARGINAL AT THIS TIME... AND A MORE LIKELY THREAT WILL BE MARGINALLY SEVERE HAIL TO 1" AND DAMAGING WINDS TO 70 MPH. THE MOST LIKELY AREA FOR INITIATION STILL APPEARS TO BE NORTH OF LBB AND EASTWARD TOWARDS THE CHILDRESS AREA. LATER IN THE EVENING...A PACIFIC FRONT WILL SWEEP THROUGH THE AREA...AND LIKELY INITIATE MORE STORMS WITH A MORE LINEAR MODE. STORMS WILL LIKELY EXIT THE AREA TO THE EAST BY 06Z. FOR TOMORROW...BREEZY WESTERLY WINDS BETWEEN 20-30 MPH WILL PERSIST ACROSS THE AREA DURING THE AFTERNOON...WHICH WHEN COMBINED WITH LOW DEWPOINTS WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS....ESPECIALLY ACROSS THE ROLLING PLAINS WHERE WARMER TEMPERATURES WILL RESULT IN LOWER RH VALUES... LONG TERM... BY SUNDAY EVENING...FLOW ACROSS THE REGION WILL BE ZONAL TO SLIGHTLY WEST SOUTHWESTERLY AS TODAY/S WIND MAKER EJECTS INTO THE GREAT LAKES. TROUGH OUT WEST CONTINUES TO DEEPEN AND APPROACH LATE MONDAY NIGHT. FLOW BECOMES NORTHWESTERLY BY WEDNESDAY WITH AN EMBEDDED TROUGH DUE IN ON THURSDAY AND ANOTHER TROUGH DIGGING INTO THE SOUTHWEST BY FRIDAY THOUGH MORE LATITUDINALLY ORIENTED THAN THE EARLY WEEK SYSTEM. RIDGING BUILDS OUT WEST WITH STRONG NNW FLOW WITH DECENT COLD AIR ADVECTION. COLD FRONT SHOULD FINALLY MAKE IT INTO THE AREA SUNDAY EVENING WITH WINDS BECOMING MORE OR LESS EASTERLY AND REMAINING IN FAVORABLE UPSLOPE REGIME FOR MOISTURE ADVECTION. NAM/GFS/ECM HAVE COME INTO GOOD AGREEMENT WITH SOME FAIRLY SUBSTANTIVE MOISTURE ADVECTION MONDAY EVENING PERHAPS MAKING IT A BIT FURTHER WEST THAN EARLIER THOUGHT. NEVERTHELESS...GENERAL TRENDS IN THE FORECAST REMAIN INSOFAR AS MOISTURE GOES...BUT...WITH THE GREATER MOISTURE...PRECIPITATION PHASE IS A BIT LESS CERTAIN WITH PHASE REMAINING LIQUID UNTIL WRAP AROUND ON THE BACK SIDE OF THE LOW...WITH LOWER TEMPS. GIVEN THIS FAIRLY RADICAL CHANGE THIS RUN...WILL HOLD OFF ON MAKING MAJOR CHANGES TO ONGOING FORECAST FOR NOW. INTO WEDNESDAY...DRIER AIR WILL CONTINUE TO FILTER INTO THE REGION AND START A WARMING TREND AFTER BOTTOMING OUT ON TUESDAY. THOUGH WINDS BACK TO SOUTHWESTERLY ON WEDNESDAY...COLD FRONT IN WEDNESDAY NIGHT/THURSDAY MORNING WILL USHER IN BREEZY NORTHERLY WINDS ONCE AGAIN WITH YET COOLER AIR SURGING SOUTHWARD INTO FRIDAY WITH DRY WEATHER TO PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 25 53 20 50 24 / 0 0 0 10 40 TULIA 28 57 26 51 26 / 0 0 0 10 40 PLAINVIEW 29 58 24 54 26 / 0 0 0 0 40 LEVELLAND 29 59 24 57 24 / 0 0 0 0 20 LUBBOCK 31 60 23 57 26 / 0 0 0 0 20 DENVER CITY 25 59 29 58 30 / 0 0 0 0 20 BROWNFIELD 29 60 24 59 28 / 0 0 0 0 20 CHILDRESS 36 65 26 56 27 / 50 0 0 0 40 SPUR 36 64 29 59 31 / 20 0 0 0 20 ASPERMONT 40 66 30 62 36 / 20 0 0 0 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1001 PM CST SAT FEB 9 2013 .UPDATE... HAVE DONE A QUICK UPDATE TO CLEAN UP THE GRIDS AND TRIM BACK POPS. SEVERE CONVECTION HAS QUICKLY COME TO AN END...THOUGH WE COULD STILL SEE A FEW SHOWERS OR STORMS YET OVER THE NEXT HOUR OR TWO ACROSS THE FAR EASTERN ZONES BEFORE THE PACIFIC FRONT CLEARS THE AREA. OTHERWISE...DRY AND BREEZY CONDITIONS WILL BE THE RULE BEHIND THE FRONT OVERNIGHT. && .PREV DISCUSSION... /ISSUED 821 PM CST SAT FEB 9 2013/ UPDATE... WE HAVE ALLOWED THE WIND ADVISORY AND WARNING TO EXPIRE ON SCHEDULE AT 8 PM. WINDS...IN GENERAL...ARE COMING DOWN...THOUGH A FEW SPOTS IMMEDIATELY BEHIND THE ADVANCING PACIFIC FRONT MAY BRIEFLY TOUCH ADVISORY LEVELS. OTHER CONCERN WILL CONTINUE TO REVOLVE AROUND DEVELOPING CONVECTION THAT IS FORMING ACROSS THE NORTHEAST ZONES CURRENTLY. THIS CONVECTION IS OCCURRING IN A WEAKLY UNSTABLE AIRMASS...BUT IS SUPPORTED BY INCREASING LARGE SCALE ASCENT AND INCREASED LOW-LEVEL FORCING AS A PACIFIC FRONT IS IMPINGING ON THE IMPROVED LOW-LEVEL MOISTURE RESIDING ACROSS ROUGHLY THE EASTERN HALF OF THE CWA. COULD YET SEE A FEW STRONG/SEVERE STORMS...LIKELY FAVORING THE NORTHEAST ZONES. IT BECOMES MORE UNCERTAIN HOW FAR SOUTH THE CONVECTION CAN DEVELOP INTO THE ROLLING PLAINS AS LOW-LEVEL CONVERGENCE IS PROGGED TO WEAKEN WITH SOUTHERN EXTENT AND CIN INCREASE. REGARDLESS...CONVECTION WILL QUICKLY SHIFT EAST...AND LIKELY BE OUT OF THE CWA BY MIDNIGHT. PREV DISCUSSION... /ISSUED 540 PM CST SAT FEB 9 2013/ AVIATION... GUSTY STRONG WINDS WILL BE THE MAIN CONCERN AT BOTH TERMINALS THROUGH 1 OR 2Z...AFTER WHICH THE WINDS SHOULD DECREASE TO LESS THAN ABOUT 18 KTS SUSTAINED. SOME LIGHT BLOWING DUST IS EXPECTED AT KLBB THROUGH 1Z. ALSO...THERE IS A CHANCE OF TSRA IN THE VICINITY OF KCDS THROUGH ABOUT 4Z. A FRONT WILL MOVE EAST ACROSS THE AREA BEFORE MIDNIGHT BRINGING A WIND SHIFT FROM SW TO WEST BUT WITH NOT MUCH CHANGE IN WIND SPEED GIVEN THE TIME OF DAY. SUNDAY MORNING...THE WINDS WILL RAMP UP AGAIN AS STRONG W-NW WINDS ALOFT MIX DOWN. SOME LIGHT BLOWING DUST WILL BE POSSIBLE AT LUBBOCK AGAIN BY MIDDAY. THE WINDS WILL START TO DIMINISH SUNDAY AFTERNOON. PREV DISCUSSION... /ISSUED 304 PM CST SAT FEB 9 2013/ SHORT TERM... A BUSY AFTERNOON IS IN STORE FOR THE CWA... WITH BOTH HIGH WINDS IN THE WEST AND THE POSSIBILITY FOR STORMS IN THE EAST. AS EXPECTED... A POTENT TROUGH IS CURRENTLY ADVANCING ON WEST TEXAS... WITH A 500MB KT MAX OF OVER 100KT CURRENTLY SITUATED OVER EASTERN NEW MEXICO. HIGH CLOUDS HAVE CLEARED OVER MOST OF THE NW PORTION OF THE CWA AND NEW MEXICO...ALLOWING FOR DEEP MIXING AND VERY STRONG WINDS ACROSS MOST OF EASTERN NEW MEXICO. WINDS HAVE BEEN SLOW TO VEER IN WEST TEXAS THIS AFTERNOON...ALLOWING DEWPOINTS TO CLIMB INTO THE UPPER 30S AND NEAR 40 ACROSS MOST OF THE CAPROCK AS OF 18Z. HOWEVER... SURFACE OBS AND RADAR TRENDS ARE INDICATING THAT WINDS ARE FINALLY BEGINNING TO VEER SLIGHTLY IN THE WEST... WHICH HAS RESULTED IN RAPID DRYING AND INCREASING WIND SPEEDS JUST EAST OF THE TEXAS NEW MEXICO BORDER. GIVEN THESE TRENDS... HAVE OPTED TO UPGRADE PARMER...CASTRO AND BAILEY COUNTIES TO A HIGH WIND WARNING THROUGH 02Z. FIRE WEATHER CONCERNS ARE STILL MINIMAL... ESPECIALLY GIVEN THE HIGHER THAN ANTICIPATED DEWPOINTS ACROSS THE WEST AND MOIST FUEL CONDITIONS... HOWEVER ELEVATED FIRE WEATHER CONDITIONS AND SOME RED FLAG MINUTES WILL BE PRESENT NEAR THE TX/NM BORDER THROUGH THE EARLY EVENING WHERE THE AIR WILL BE DRIEST AND WINDS STRONGEST. FURTHER EAST... THE FORECAST STILL APPEARS TO BE LARGELY ON TRACK AS MOISTURE CONTINUES TO RETURN ACROSS THE EAST. RADAR AND SURFACES OBSERVATIONS INDICATE THE BEGINNINGS OF A DRYLINE FORMING JUST TO THE EAST OF THE TX/NM STATE LINE...AND APPEARS TO BE SLOWLY ADVANCING EAST. IN ADDITION... VISIBLE SATELLITE IMAGERY IS SHOWING AN INCREASE IN CUMULIFORM CLOUDS JUST TO THE DRY SIDE OF THIS DEVELOPING DRYLINE. DEWPOINTS AS OF 20Z HAVE REACHED THE UPPER 40S ACROSS THE SOUTHEAST...TO NEAR 40 IN THE NORTHERN ROLLING PLAINS...WHICH IS A BIT LOWER THAN YOU WOULD LIKE FOR STORM DEVELOPMENT. AS SUCH... INSTABILITY IS STILL VERY WEAK ACROSS THE AREA...WITH MAXIMUM VALUES OF NEAR 500 J/KG RESTRICTED TO THE SOUTHEAST. THERE STILL REMAINS SOME TIME FOR MOISTURE TO INCREASE...AND IT STILL SEEMS WITHIN REASON THAT DEWPOINTS WILL REACH THE UPPER 40S TO LOW 50S WITHIN THE NEXT FEW HOURS. LOCAL HIGH RESOLUTION MODELS...INCLUDING THE TTUWRF AND TO A LESSER EXTENT THE HRRR... SEEM TO BE SUGGESTING THAT INITIATION MAY HOLD OFF UNTIL 00Z... HOWEVER THE RUC IS STILL FIRING AROUND 22Z. GIVEN CURRENT TRENDS... IT SEEMS THAT THE LATER INITIATION SOLUTIONS SEEM MORE PLAUSIBLE. GIVEN THE VERY STRONGLY SHEARED WIND FIELDS... ANY STORMS THAT CAN MANAGE TO INITIATE EARLY WILL VERY LIKELY BE SUPERCELLULAR... AND COULD POSE A VERY ISOLATED TORNADO THREAT IF MOISTURE CAN CONTINUE TO RISE. HOWEVER...THIS THREAT APPEARS TO BE VERY MARGINAL AT THIS TIME... AND A MORE LIKELY THREAT WILL BE MARGINALLY SEVERE HAIL TO 1" AND DAMAGING WINDS TO 70 MPH. THE MOST LIKELY AREA FOR INITIATION STILL APPEARS TO BE NORTH OF LBB AND EASTWARD TOWARDS THE CHILDRESS AREA. LATER IN THE EVENING...A PACIFIC FRONT WILL SWEEP THROUGH THE AREA...AND LIKELY INITIATE MORE STORMS WITH A MORE LINEAR MODE. STORMS WILL LIKELY EXIT THE AREA TO THE EAST BY 06Z. FOR TOMORROW...BREEZY WESTERLY WINDS BETWEEN 20-30 MPH WILL PERSIST ACROSS THE AREA DURING THE AFTERNOON...WHICH WHEN COMBINED WITH LOW DEWPOINTS WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS....ESPECIALLY ACROSS THE ROLLING PLAINS WHERE WARMER TEMPERATURES WILL RESULT IN LOWER RH VALUES... LONG TERM... BY SUNDAY EVENING...FLOW ACROSS THE REGION WILL BE ZONAL TO SLIGHTLY WEST SOUTHWESTERLY AS TODAY/S WIND MAKER EJECTS INTO THE GREAT LAKES. TROUGH OUT WEST CONTINUES TO DEEPEN AND APPROACH LATE MONDAY NIGHT. FLOW BECOMES NORTHWESTERLY BY WEDNESDAY WITH AN EMBEDDED TROUGH DUE IN ON THURSDAY AND ANOTHER TROUGH DIGGING INTO THE SOUTHWEST BY FRIDAY THOUGH MORE LATITUDINALLY ORIENTED THAN THE EARLY WEEK SYSTEM. RIDGING BUILDS OUT WEST WITH STRONG NNW FLOW WITH DECENT COLD AIR ADVECTION. COLD FRONT SHOULD FINALLY MAKE IT INTO THE AREA SUNDAY EVENING WITH WINDS BECOMING MORE OR LESS EASTERLY AND REMAINING IN FAVORABLE UPSLOPE REGIME FOR MOISTURE ADVECTION. NAM/GFS/ECM HAVE COME INTO GOOD AGREEMENT WITH SOME FAIRLY SUBSTANTIVE MOISTURE ADVECTION MONDAY EVENING PERHAPS MAKING IT A BIT FURTHER WEST THAN EARLIER THOUGHT. NEVERTHELESS...GENERAL TRENDS IN THE FORECAST REMAIN INSOFAR AS MOISTURE GOES...BUT...WITH THE GREATER MOISTURE...PRECIPITATION PHASE IS A BIT LESS CERTAIN WITH PHASE REMAINING LIQUID UNTIL WRAP AROUND ON THE BACK SIDE OF THE LOW...WITH LOWER TEMPS. GIVEN THIS FAIRLY RADICAL CHANGE THIS RUN...WILL HOLD OFF ON MAKING MAJOR CHANGES TO ONGOING FORECAST FOR NOW. INTO WEDNESDAY...DRIER AIR WILL CONTINUE TO FILTER INTO THE REGION AND START A WARMING TREND AFTER BOTTOMING OUT ON TUESDAY. THOUGH WINDS BACK TO SOUTHWESTERLY ON WEDNESDAY...COLD FRONT IN WEDNESDAY NIGHT/THURSDAY MORNING WILL USHER IN BREEZY NORTHERLY WINDS ONCE AGAIN WITH YET COOLER AIR SURGING SOUTHWARD INTO FRIDAY WITH DRY WEATHER TO PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 25 53 20 50 24 / 0 0 0 10 40 TULIA 28 57 26 51 26 / 0 0 0 10 40 PLAINVIEW 29 58 24 54 26 / 0 0 0 0 40 LEVELLAND 29 59 24 57 24 / 0 0 0 0 20 LUBBOCK 31 60 23 57 26 / 0 0 0 0 20 DENVER CITY 25 59 29 58 30 / 0 0 0 0 20 BROWNFIELD 29 60 24 59 28 / 0 0 0 0 20 CHILDRESS 36 65 26 56 27 / 50 0 0 0 40 SPUR 36 64 29 59 31 / 20 0 0 0 20 ASPERMONT 40 66 30 62 36 / 20 0 0 0 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33/23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
256 PM CST SUN FEB 10 2013 .SHORT TERM...THROUGH TUESDAY NIGHT 256 PM CST SUN FEB 10 2013 MAIN FORECAST CONCERN IS WITH THE PRECIPITATION TRENDS TONIGHT AND MONDAY. SURFACE ANALYSIS THIS AFTERNOON SHOWS A STRONG AREA OF LOW PRESSURE NEAR KSUX. LOCAL AND REGIONAL RADARS SHOWING THE MAIN BAND OF PRECIPITATION AHEAD OF THE LOW EXTENDS FROM NORTHEAST MINNESOTA ACROSS MUCH OF WISCONSIN. DRY SLOT COMING IN BEHIND THE BAND WITH DRIZZLE OCCURRING IN IT. THE UPPER LEVEL LOW OVER SOUTHEAST SOUTH DAKOTA WILL MOVE PAST THE AREA OVERNIGHT. HOWEVER...THE MAIN FORCING IS ALREADY MOVING PAST THE AREA WITH THE BAND OF PRECIPITATION. THE PV ADVECTION IN THE 500-300 MB LAYER WILL RAPIDLY DECREASE THIS EVENING AND WITH THE BEST ISENTROPIC UP GLIDE MOVING OUT AS WELL EXPECT ONLY SOME DRIZZLE TO BE THE DOMINANT PRECIPITATION TYPE UNTIL THE SURFACE LOW GOES BY AND THE COLDER AIR STARTS TO MOVE IN. ONCE THE LOW GOES BY...THE FORCING WILL START TO INCREASE OVERNIGHT AS THE 10.12Z NAM SHOWS THIS SYSTEM HAS A NICE TROWAL ASSOCIATED WITH IT. THIS IS IN PLACE BETWEEN THE 285K AND 295K SURFACE WHERE THE UP GLIDE ON THESE SURFACES IS BETWEEN 2 AND 5 UBARS/S. THIS UP GLIDE COMBINED WITH THE COLDER AIR COMING IN WILL CHANGE THE LIQUID PRECIPITATION OVER TO LIGHT SNOW DURING THE LATE EVENING AND OVERNIGHT HOURS. THE LIGHT SNOW SHOULD THEN CONTINUE THROUGH MONDAY MORNING BEFORE THE TROWAL MOVES AWAY FROM THE REGION MONDAY AFTERNOON. THE LIGHT SNOW SHOULD REALLY TAPER OFF MONDAY AFTERNOON AS THIS OCCURS. ACCUMULATIONS TONIGHT AND MONDAY SHOULD GENERALLY BE AROUND AN INCH WITH POSSIBLY A COUPLE OF INCHES UP IN TAYLOR COUNTY. THE WINDS ON THE BACK SIDE OF THE SURFACE LOW WILL INCREASE WITH SUSTAINED WEST TO NORTHWEST WINDS OF 15 TO 30 MPH EXPECTED OVERNIGHT THROUGH MONDAY. NOT ANTICIPATING THE NEED FOR AN ADVISORY WITH GUSTS STAYING UNDER 40 MPH. .LONG TERM...WEDNESDAY THROUGH SUNDAY 256 PM CST SUN FEB 10 2013 NORTHWEST FLOW ALOFT WILL SET UP OVER THE UPPER MIDWEST IN THE WAKE OF THE CURRENT STORM SYSTEM. THIS WILL ALLOW A SYSTEM TO DROP INTO THE REGION FOR THE MIDDLE OR END OF THE WEEK. THE MODELS SHOW VERY LITTLE CONSISTENCY ON THE TIMING OF THIS FEATURE. THE 10.12Z GFS IS THE FASTEST BRINGING IN WEDNESDAY AFTERNOON WHILE THE 10.12Z GEM IS THE SLOWEST AND STRONGEST AND DOES NOT BRING IT IN UNTIL THURSDAY NIGHT. UNTIL THESE TIMING DIFFERENCES ARE WORKED OUT...WILL NEED TO CARRY A MENTION OF PRECIPITATION FROM WEDNESDAY NIGHT THROUGH FRIDAY WITH THE BEST CHANCES CENTERED ON WEDNESDAY NIGHT AND THURSDAY. THE SURFACE LOW MAY PASS BY JUST TO THE NORTH OF THE AREA THURSDAY BRINGING ENOUGH WARM AIR FOR A MIX OF RAIN AND SNOW ACROSS THE SOUTH WITH LIGHT SNOW EXPECTED ELSEWHERE. && .AVIATION...THROUGH 18Z MONDAY 1130 AM CST SUN FEB 10 2013 MAIN AVIATION CONCERNS ARE IFR TO MVFR AND WINDY CONDITIONS AT BOTH RST AND LSE TAF SITES THROUGH TAF PERIOD. LATEST 17Z METARS REPORTING TEMPERATURES IN THE MIDDLE 30S AND RAIN ACROSS MUCH OF THE AREA. TEMPERATURES SHOULD REMAIN ABOVE FREEZING AND CLIMB INTO THE MIDDLE TO UPPER 30S AND ALLOW FOR ANY PRECIPITATION TO BE DRIZZLE OR RAIN THROUGH THE AFTERNOON HOURS TO AROUND 04-06Z MONDAY AT BOTH TAF SITES. LATEST 10.15Z RAP AND 10.12Z NAM BUFKIT SOUNDINGS SHOWING NEAR SURFACE BOUNDARY LAYER TO BE SATURATED THROUGH TAF PERIOD...WITH THE LATEST CEILING HEIGHTS BEING REPORTED IN THE RANGE OF 400-1300 FEET ACROSS THE REGION. EXPECT IFR TO LIFR CONDITIONS AT RST AND MVFR TO IFR CONDITIONS AT LSE THROUGH TAF PERIOD. THE LATEST DETERMINISTIC 10.12Z NAM AND 10.15Z RAP INDICATE COLD FRONT TO TRACK ACROSS THE AREA THIS EVENING. WITH A TIGHT PRESSURE GRADIENT ON THE BACKSIDE OF THE COLD FRONT...WINDS WILL SHIFT TO THE WEST TO NORTHWEST AT BOTH RST AND LSE TAF SITES BETWEEN 04-06Z MONDAY TIME FRAME AND INCREASE TO 15 TO 20 KNOTS WITH GUST UP TO 25 TO 30 KNOTS. IN ADDITION...COLDER AIR WILL FILTER IN BEHIND THE COLD FRONT AND CHANGE THE RAIN OR DRIZZLE TO ALL SNOW ACROSS THE AREA. WITH THE COMBINATION OF SNOW AND WINDY CONDITIONS...CANNOT RULE OUT THE POSSIBILITY OF SOME PATCHY BLOWING SNOW AFTER 10Z MONDAY AT RST. FOR NOW HAVE KEPT MENTION OF BLOWING SNOW OUT OF THE TAF SITES...HOWEVER KEPT VISIBILITIES IN THE MVFR RANGE. && .HYDROLOGY... 256 PM CST SUN FEB 10 2013 WITH THE BULK OF THE RAINFALL NOW OVER...THE POTENTIAL FOR FLOODING IS PRETTY LOW. HOWEVER...WILL CONTINUE TO MONITOR STREAMS AS THE RUN OFF WORKS INTO THE WATER WAYS POSSIBLY CAUSING SOME IN BANK RISES. ICE JAMS NOT TOTALLY OUT OF THE QUESTION...BUT DO NOT BELIEVE THERE WILL BE ENOUGH RISES TO BREAK UP THE ICE ON THE LARGER RIVERS. ICE JAM POTENTIAL SHOULD BE LIMITED TO THE SMALL STREAMS. && .ARX WATCHES/WARNINGS/ADVISORIES... 256 PM CST SUN FEB 10 2013 WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ017- 029. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...DTJ HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 AM CST SUN FEB 10 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT 230 AM CST SUN FEB 10 2013 FORECAST FOCUS IS ON THE STORM SYSTEM THAT SLIDES ACROSS THE REGION TODAY...WITH CONTINUING PCPN INTO MONDAY. LATEST WATER VAPOR SATELLITE IMAGERY PLACES THE SHORTWAVE OVER THE SOUTHERN PLAINS...WITH THE 00Z MODEL RUNS ALL DRIVING IT NORTHEAST ACROSS THE FORECAST AREA BY THIS EVENING. RELATIVELY WEAK FRONTOGENETIC FORCING VIA NAM12/RAP LOOKS RESPONSIBLE FOR THE CURRENT BAND OF LIGHT PCPN RUNNING NORTHWEST-SOUTHEAST FROM SOUTHERN MN THROUGH IA. THIS WILL CONTINUE TO LIFT NORTHEAST THROUGH THE MORNING. THE BULK OF THIS SYSTEM/S FORCING IS POST THIS BAND HOWEVER...WITH THE STRONG LOW LEVEL THERMODYNAMIC LIFT VIA WARM ADVECTION/ISENTROPIC UPGLIDE ON THE LEADING EDGE OF THE SHORTWAVE LIFTING ACROSS THE REGION FROM THE LATE MORNING THROUGH THE AFTERNOON. THE MODELS KEY ON THIS FORCING FOR THE SYSTEM/S MAIN PCPN BAND. PLENTY OF MOISTURE TO WORK WITH FOR EARLY FEB...WITH A STRONG PUSH OF 850 MB MOISTURE TRANSPORT ON THE NOSE OF 50 KT LOW LEVEL JET. PWS ARE NEARLY 300 PERCENT ABOVE NORMAL WITH SREF ANOMALIES AROUND +3. IN ADDITION...THE FRONTOGENETIC FORCING IS NEARLY UPRIGHT AT TIMES...PER NORTHEAST-SOUTHWEST RUNNING X-SECTIONS...AND THIS COUPLED WITH THE NOSE OF THE LOW LEVEL JET COULD RESULT IN SOME CONVECTION. A CRACK OR TWO OF THUNDER CAN/T BE RULED OUT...MOSTLY TO THE SOUTH. THE PCPN BAND MOVES NORTH OF THE FORECAST AREA BY 00Z...WITH THE STORM SYSTEM/S SFC LOW OVER NORTHERN IA BY THIS TIME. NAM/GFS CONTINUE TO INDICATE THAT A SMALLER AREA OF PCPN WILL DEVELOP WITH THE LOW...ASSOCIATED WITH UPPER LEVEL ENERGY BEING WRAPPED HARD AROUND THE STORM...AND SOME SFC TROUGHINESS RESULTING IN CONVERGENCE. THIS AREA OF ENHANCED QPF WOULD FALL ACROSS SOUTHEAST MN THIS EVENING...SHUFFLING ACROSS NORTHERN WI OVERNIGHT. ELSEWHERE...ENOUGH BROADSCALE LIFT WITH AMPLE SATURATION THAT AREAS OF LIGHT PCPN ARE LIKELY. WITH THE COLD FRONTAL PASSAGE IN THE EVENING...EXPECT A TRANSITION FROM RAIN TO SNOW. THE SNOW WILL LINGER ON MONDAY...WITH AN INVERTED SFC TROUGH HANGING WEST OF THE EASTWARD MOVING LOW...BITS OF UPPER LEVEL ENERGY...AND FAVORABLE LOW LEVEL LAPSE RATES HELPING SPARK THE SNOW. THE BETTER CHANCES WILL LIE MOSTLY ALONG AND NORTH OF I-90...WITH ADDITIONAL ACCUMULATIONS ON MONDAY OF AN INCH OR LESS. AS IT HAS APPEARED THE PAST FEW DAYS...THERE APPEARS TO BE 3 DIFFERENT PCPN PHASES WITH THIS STORM SYSTEM...OR PERHAPS 4 NOW. SFC OBS WITH THE FRONTOGENETIC PCPN BAND MOVING NORTHEAST INDICATES MOSTLY RAIN RIGHT NOW...ALTHOUGH THE CONVECTIVE NATURE WOULD SUGGEST THAT ANY HIGH RETURNS COULD BE...OR PERHAPS ARE MORE LIKELY TO BE...SLEET. RAP BUFKIT SOUNDINGS OVER NORTHEAST IA HAVE A 1-2 C WARM LAYER...WHICH GRADUALLY DEEPENS. THE ATMOSPHERE CONTINUES TO WARM...BUT AS IT DOES...THE CLOUDS LOSE THEIR ICE BEHIND THIS FIRST PCPN BAND. CURRENT IR/SATELLITE CLOUD TEMPS INDICATE THIS AS WELL. SO...COULD SEE A FREEZING RAIN/SLEET MIX CHANGE OVER TO FREEZING DRIZZLE FOR EARLY THIS MORNING...ALL SFC TEMP DEPENDENT OF COURSE. BUT REMEMBER - EVEN AS TEMPS WARM THROUGH THE DAY...ROAD TEMPS ARE COLDER...MOSTLY IN THE UPPER 20S...AND ICY SPOTS WILL DEVELOP IF THEY ARE UNTREATED. THE MAIN BAND OF PCPN...THE BAND THAT WILL BRING MOST OF THE QPF TO THE FORECAST AREA...IS EXPECTED TO DEVELOP JUST TO THE SOUTHWEST...MOVING NORTHEAST ACROSS THE REGION LATE MORNING/AFTERNOON. GOOD PUSH OF LOW LEVEL WARM AIR WITH THIS PCPN...GENERALLY 1-3 C AT MAX. THIS IS SUGGESTIVE OF ONLY PARTIAL MELTING...WHICH WOULD RESULT IN SLEET. HOWEVER...THE DEPTH OF THIS WARM LAYER EXCEEDS 3 KFT IN SOME LOCATIONS - WHICH COULD RESULT IN FULL MELTING. HOWEVER...THE TRACK OF THE SYSTEM KEEPS IT A BIT COLDER WEST OF THE MISSISSIPPI RIVER...EVIDENCED IN A WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS. NAM12 BUFKIT SOUNDINGS AT KRST WOULD FAVOR SNOW TO A SNOW/RAIN MIX...SFC TEMP DEPENDENT. NOT MUCH OF A DENDRITIC SNOW REGION...BUT ITS ISOTHERMAL AROUND 0 C FOR A FEW HOURS. WOULD EXPECT A WET SNOW WITH LOWER SNOW RATIOS. WILL HAVE TO TREND FROM WEST TO EAST AND SOUTH TO NORTH WITH PCPN TYPES. AFTER THIS BAND GOES THROUGH THE MODELS CONTINUE TO POINT TO A SHALLOWING OF THE CLOUD LAYER AND LOSS OF ICE AS A MID LEVEL DRY INTRUSION WORKS ACROSS THE REGION. DRIZZLE WOULD BE THE PCPN TYPE...OUTSIDE OF THE BAND OF PCPN ASSOCIATED WITH THE WRAP AROUND ENERGY. THAT SHOULD FALL AS SNOW. THE CLOUD LAYER DEEPENS AGAIN AND WELCOMES ICE BACK INTO THE PTYPE EQUATION EARLY THIS EVENING...POST THE SYSTEM/S COLD FRONT. AREAS OF LIGHT SNOW ARE LIKELY...WITH MINOR ACCUMULATIONS. THIS SNOW CONTINUES ON MONDAY...AS ALREADY MENTIONED. OVERALL...ITS A MESS. A LOT GOING ON WITH ONLY SMALL CHANGES IN HOW WARM IT GETS AND/OR DEPTH OF THE WARM LAYER HAVING A SIGNIFICANT IMPACT ON WHAT FALLS. THAT DOESN/T EVEN INCLUDE THE YES/NO ICE IN THE CLOUD QUESTION. IT DOES APPEAR THERE COULD BE A BIT MORE FROZEN PCPN THEN PREVIOUS FORECASTS HAVE INDICATED. EITHER WAY...THE WINTER WEATHER ADVISORY LOOKS GOOD AND WILL CONTINUE. .LONG TERM...WEDNESDAY THROUGH SATURDAY 230 AM CST SUN FEB 10 2013 MODELS REMAIN AT ODDS IN HOW TO HANDLE A NORTHWEST FLOW SHORTWAVE SLATED TO SPIN ACROSS THE REGION TOWARD THE END OF THE WORK WEEK. THE GFS MOVES THIS FEATURE IN WED NIGHT...KICKING IT EAST BY THU NIGHT. THE EC IS WEAKER WITH THIS SHORTWAVE...AND SLOWER...NOT MOVING IT UNTIL THU. IT MIGHT BE A BIT MORE SOUTH TOO. THE GEM SIDES MORE TOWARD THE GFS WITH STRENGTH AND POSITIONING...BUT IS SLOWER...ALSO MOVING IN OVERNIGHT WED. ALL PRODUCE QPF...MORE IN THE GEM/GFS...AND ALL WOULD BE SNOW. GOOD AMOUNT OF CONSISTENCY IN THE EC WITH POSITIONING...ALTHOUGH STRENGTH HAS VARIED. THE GFS HAS JUMPED AROUND. WILL LEAN ON AN EC/CONSENSUS SOLUTION FOR THIS TIME PERIOD. THE WEEKEND LOOKS COLDER AS A DEEPER UPPER LEVEL TROUGH IS CARVED OUT POST THE WED/THU SHORTWAVE. HIGHS IN THE TEENS WITH LOWS CLOSE TO ZERO LOOK REASONABLE. && .AVIATION...THROUGH 18Z MONDAY 1130 AM CST SUN FEB 10 2013 MAIN AVIATION CONCERNS ARE IFR TO MVFR AND WINDY CONDITIONS AT BOTH RST AND LSE TAF SITES THROUGH TAF PERIOD. LATEST 17Z METARS REPORTING TEMPERATURES IN THE MIDDLE 30S AND RAIN ACROSS MUCH OF THE AREA. TEMPERATURES SHOULD REMAIN ABOVE FREEZING AND CLIMB INTO THE MIDDLE TO UPPER 30S AND ALLOW FOR ANY PRECIPITATION TO BE DRIZZLE OR RAIN THROUGH THE AFTERNOON HOURS TO AROUND 04-06Z MONDAY AT BOTH TAF SITES. LATEST 10.15Z RAP AND 10.12Z NAM BUFKIT SOUNDINGS SHOWING NEAR SURFACE BOUNDARY LAYER TO BE SATURATED THROUGH TAF PERIOD...WITH THE LATEST CEILING HEIGHTS BEING REPORTED IN THE RANGE OF 400-1300 FEET ACROSS THE REGION. EXPECT IFR TO LIFR CONDITIONS AT RST AND MVFR TO IFR CONDITIONS AT LSE THROUGH TAF PERIOD. THE LATEST DETERMINISTIC 10.12Z NAM AND 10.15Z RAP INDICATE COLD FRONT TO TRACK ACROSS THE AREA THIS EVENING. WITH A TIGHT PRESSURE GRADIENT ON THE BACKSIDE OF THE COLD FRONT...WINDS WILL SHIFT TO THE WEST TO NORTHWEST AT BOTH RST AND LSE TAF SITES BETWEEN 04-06Z MONDAY TIME FRAME AND INCREASE TO 15 TO 20 KNOTS WITH GUST UP TO 25 TO 30 KNOTS. IN ADDITION...COLDER AIR WILL FILTER IN BEHIND THE COLD FRONT AND CHANGE THE RAIN OR DRIZZLE TO ALL SNOW ACROSS THE AREA. WITH THE COMBINATION OF SNOW AND WINDY CONDITIONS...CANNOT RULE OUT THE POSSIBILITY OF SOME PATCHY BLOWING SNOW AFTER 10Z MONDAY AT RST. FOR NOW HAVE KEPT MENTION OF BLOWING SNOW OUT OF THE TAF SITES...HOWEVER KEPT VISIBILITIES IN THE MVFR RANGE. && .HYDROLOGY... 230 AM CST SUN FEB 10 2013 MORNING RAIN...COUPLED WITH A FEW INCHES OF SNOW PACK...WILL LEAD TO RUNOFF INTO AREA WATERWAYS. NEARLY A FULL RELEASE AS GROUNDS ARE FROZEN. EXPECT SOME IN BANK RISES...BUT UNLESS EXPECTED AMOUNTS ARE SIGNIFICANTLY HIGHER...DON/T ANTICIPATE ANY WIDESPREAD FLOODING CONCERNS. THE POTENTIAL FOR ICE JAMS WILL HAVE TO BE MONITORED. && .ARX WATCHES/WARNINGS/ADVISORIES... 230 AM CST SUN FEB 10 2013 WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ032>034-041- 042-053>055-061. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS EVENING FOR WIZ017-029-043-044. MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ086-087-094- 095. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ079-088-096. IA...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ008>010-018- 019-029. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ011-030. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...DTJ HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
601 AM CST SUN FEB 10 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT 230 AM CST SUN FEB 10 2013 FORECAST FOCUS IS ON THE STORM SYSTEM THAT SLIDES ACROSS THE REGION TODAY...WITH CONTINUING PCPN INTO MONDAY. LATEST WATER VAPOR SATELLITE IMAGERY PLACES THE SHORTWAVE OVER THE SOUTHERN PLAINS...WITH THE 00Z MODEL RUNS ALL DRIVING IT NORTHEAST ACROSS THE FORECAST AREA BY THIS EVENING. RELATIVELY WEAK FRONTOGENETIC FORCING VIA NAM12/RAP LOOKS RESPONSIBLE FOR THE CURRENT BAND OF LIGHT PCPN RUNNING NORTHWEST-SOUTHEAST FROM SOUTHERN MN THROUGH IA. THIS WILL CONTINUE TO LIFT NORTHEAST THROUGH THE MORNING. THE BULK OF THIS SYSTEM/S FORCING IS POST THIS BAND HOWEVER...WITH THE STRONG LOW LEVEL THERMODYNAMIC LIFT VIA WARM ADVECTION/ISENTROPIC UPGLIDE ON THE LEADING EDGE OF THE SHORTWAVE LIFTING ACROSS THE REGION FROM THE LATE MORNING THROUGH THE AFTERNOON. THE MODELS KEY ON THIS FORCING FOR THE SYSTEM/S MAIN PCPN BAND. PLENTY OF MOISTURE TO WORK WITH FOR EARLY FEB...WITH A STRONG PUSH OF 850 MB MOISTURE TRANSPORT ON THE NOSE OF 50 KT LOW LEVEL JET. PWS ARE NEARLY 300 PERCENT ABOVE NORMAL WITH SREF ANOMALIES AROUND +3. IN ADDITION...THE FRONTOGENETIC FORCING IS NEARLY UPRIGHT AT TIMES...PER NORTHEAST-SOUTHWEST RUNNING X-SECTIONS...AND THIS COUPLED WITH THE NOSE OF THE LOW LEVEL JET COULD RESULT IN SOME CONVECTION. A CRACK OR TWO OF THUNDER CAN/T BE RULED OUT...MOSTLY TO THE SOUTH. THE PCPN BAND MOVES NORTH OF THE FORECAST AREA BY 00Z...WITH THE STORM SYSTEM/S SFC LOW OVER NORTHERN IA BY THIS TIME. NAM/GFS CONTINUE TO INDICATE THAT A SMALLER AREA OF PCPN WILL DEVELOP WITH THE LOW...ASSOCIATED WITH UPPER LEVEL ENERGY BEING WRAPPED HARD AROUND THE STORM...AND SOME SFC TROUGHINESS RESULTING IN CONVERGENCE. THIS AREA OF ENHANCED QPF WOULD FALL ACROSS SOUTHEAST MN THIS EVENING...SHUFFLING ACROSS NORTHERN WI OVERNIGHT. ELSEWHERE...ENOUGH BROADSCALE LIFT WITH AMPLE SATURATION THAT AREAS OF LIGHT PCPN ARE LIKELY. WITH THE COLD FRONTAL PASSAGE IN THE EVENING...EXPECT A TRANSITION FROM RAIN TO SNOW. THE SNOW WILL LINGER ON MONDAY...WITH AN INVERTED SFC TROUGH HANGING WEST OF THE EASTWARD MOVING LOW...BITS OF UPPER LEVEL ENERGY...AND FAVORABLE LOW LEVEL LAPSE RATES HELPING SPARK THE SNOW. THE BETTER CHANCES WILL LIE MOSTLY ALONG AND NORTH OF I-90...WITH ADDITIONAL ACCUMULATIONS ON MONDAY OF AN INCH OR LESS. AS IT HAS APPEARED THE PAST FEW DAYS...THERE APPEARS TO BE 3 DIFFERENT PCPN PHASES WITH THIS STORM SYSTEM...OR PERHAPS 4 NOW. SFC OBS WITH THE FRONTOGENETIC PCPN BAND MOVING NORTHEAST INDICATES MOSTLY RAIN RIGHT NOW...ALTHOUGH THE CONVECTIVE NATURE WOULD SUGGEST THAT ANY HIGH RETURNS COULD BE...OR PERHAPS ARE MORE LIKELY TO BE...SLEET. RAP BUFKIT SOUNDINGS OVER NORTHEAST IA HAVE A 1-2 C WARM LAYER...WHICH GRADUALLY DEEPENS. THE ATMOSPHERE CONTINUES TO WARM...BUT AS IT DOES...THE CLOUDS LOSE THEIR ICE BEHIND THIS FIRST PCPN BAND. CURRENT IR/SATELLITE CLOUD TEMPS INDICATE THIS AS WELL. SO...COULD SEE A FREEZING RAIN/SLEET MIX CHANGE OVER TO FREEZING DRIZZLE FOR EARLY THIS MORNING...ALL SFC TEMP DEPENDENT OF COURSE. BUT REMEMBER - EVEN AS TEMPS WARM THROUGH THE DAY...ROAD TEMPS ARE COLDER...MOSTLY IN THE UPPER 20S...AND ICY SPOTS WILL DEVELOP IF THEY ARE UNTREATED. THE MAIN BAND OF PCPN...THE BAND THAT WILL BRING MOST OF THE QPF TO THE FORECAST AREA...IS EXPECTED TO DEVELOP JUST TO THE SOUTHWEST...MOVING NORTHEAST ACROSS THE REGION LATE MORNING/AFTERNOON. GOOD PUSH OF LOW LEVEL WARM AIR WITH THIS PCPN...GENERALLY 1-3 C AT MAX. THIS IS SUGGESTIVE OF ONLY PARTIAL MELTING...WHICH WOULD RESULT IN SLEET. HOWEVER...THE DEPTH OF THIS WARM LAYER EXCEEDS 3 KFT IN SOME LOCATIONS - WHICH COULD RESULT IN FULL MELTING. HOWEVER...THE TRACK OF THE SYSTEM KEEPS IT A BIT COLDER WEST OF THE MISSISSIPPI RIVER...EVIDENCED IN A WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS. NAM12 BUFKIT SOUNDINGS AT KRST WOULD FAVOR SNOW TO A SNOW/RAIN MIX...SFC TEMP DEPENDENT. NOT MUCH OF A DENDRITIC SNOW REGION...BUT ITS ISOTHERMAL AROUND 0 C FOR A FEW HOURS. WOULD EXPECT A WET SNOW WITH LOWER SNOW RATIOS. WILL HAVE TO TREND FROM WEST TO EAST AND SOUTH TO NORTH WITH PCPN TYPES. AFTER THIS BAND GOES THROUGH THE MODELS CONTINUE TO POINT TO A SHALLOWING OF THE CLOUD LAYER AND LOSS OF ICE AS A MID LEVEL DRY INTRUSION WORKS ACROSS THE REGION. DRIZZLE WOULD BE THE PCPN TYPE...OUTSIDE OF THE BAND OF PCPN ASSOCIATED WITH THE WRAP AROUND ENERGY. THAT SHOULD FALL AS SNOW. THE CLOUD LAYER DEEPENS AGAIN AND WELCOMES ICE BACK INTO THE PTYPE EQUATION EARLY THIS EVENING...POST THE SYSTEM/S COLD FRONT. AREAS OF LIGHT SNOW ARE LIKELY...WITH MINOR ACCUMULATIONS. THIS SNOW CONTINUES ON MONDAY...AS ALREADY MENTIONED. OVERALL...ITS A MESS. A LOT GOING ON WITH ONLY SMALL CHANGES IN HOW WARM IT GETS AND/OR DEPTH OF THE WARM LAYER HAVING A SIGNIFICANT IMPACT ON WHAT FALLS. THAT DOESN/T EVEN INCLUDE THE YES/NO ICE IN THE CLOUD QUESTION. IT DOES APPEAR THERE COULD BE A BIT MORE FROZEN PCPN THEN PREVIOUS FORECASTS HAVE INDICATED. EITHER WAY...THE WINTER WEATHER ADVISORY LOOKS GOOD AND WILL CONTINUE. .LONG TERM...WEDNESDAY THROUGH SATURDAY 230 AM CST SUN FEB 10 2013 MODELS REMAIN AT ODDS IN HOW TO HANDLE A NORTHWEST FLOW SHORTWAVE SLATED TO SPIN ACROSS THE REGION TOWARD THE END OF THE WORK WEEK. THE GFS MOVES THIS FEATURE IN WED NIGHT...KICKING IT EAST BY THU NIGHT. THE EC IS WEAKER WITH THIS SHORTWAVE...AND SLOWER...NOT MOVING IT UNTIL THU. IT MIGHT BE A BIT MORE SOUTH TOO. THE GEM SIDES MORE TOWARD THE GFS WITH STRENGTH AND POSITIONING...BUT IS SLOWER...ALSO MOVING IN OVERNIGHT WED. ALL PRODUCE QPF...MORE IN THE GEM/GFS...AND ALL WOULD BE SNOW. GOOD AMOUNT OF CONSISTENCY IN THE EC WITH POSITIONING...ALTHOUGH STRENGTH HAS VARIED. THE GFS HAS JUMPED AROUND. WILL LEAN ON AN EC/CONSENSUS SOLUTION FOR THIS TIME PERIOD. THE WEEKEND LOOKS COLDER AS A DEEPER UPPER LEVEL TROUGH IS CARVED OUT POST THE WED/THU SHORTWAVE. HIGHS IN THE TEENS WITH LOWS CLOSE TO ZERO LOOK REASONABLE. && .AVIATION...TODAY AND TONIGHT 600 AM CST SUN FEB 10 2013 ONE BAND OF FREEZING RAIN...SLEET...AND SNOW HAS MOVED EAST OF THE TAF SITES. IN ITS WAKE THERE ARE PATCHY AREAS OF FREEZING DRIZZLE. ANOTHER AREA OF FREEZING RAIN...SLEET...AND SNOW WILL MOVE INTO KRST AROUND 10.1530Z AND KLSE AROUND 10.16Z. ONCE THIS BAND MOVES OUT OF THE AREA...THERE WILL BE JUST SOME PATCHY DRIZZLE FOR THE AFTERNOON. SCATTERED RAIN AND SNOW SHOWERS WILL MOVE INTO THE AREA THIS EVENING...AND SNOW SHOWERS TONIGHT. UP TO A HALF INCH OF SNOW ACCUMULATION IS EXPECTED. THROUGH THE ENTIRE TIME PERIOD...BOTH CEILINGS AND VISIBILITIES WILL BE IFR TO MVFR. && .HYDROLOGY... 230 AM CST SUN FEB 10 2013 MORNING RAIN...COUPLED WITH A FEW INCHES OF SNOW PACK...WILL LEAD TO RUNOFF INTO AREA WATERWAYS. NEARLY A FULL RELEASE AS GROUNDS ARE FROZEN. EXPECT SOME IN BANK RISES...BUT UNLESS EXPECTED AMOUNTS ARE SIGNIFICANTLY HIGHER...DON/T ANTICIPATE ANY WIDESPREAD FLOODING CONCERNS. THE POTENTIAL FOR ICE JAMS WILL HAVE TO BE MONITORED. && .ARX WATCHES/WARNINGS/ADVISORIES... 230 AM CST SUN FEB 10 2013 WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ032>034-041- 042-053>055-061. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS EVENING FOR WIZ017-029-043-044. MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ086-087-094- 095. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ079-088-096. IA...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ008>010-018- 019-029. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ011-030. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...BOYNE HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
230 AM CST SUN FEB 10 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT 230 AM CST SUN FEB 10 2013 FORECAST FOCUS IS ON THE STORM SYSTEM THAT SLIDES ACROSS THE REGION TODAY...WITH CONTINUING PCPN INTO MONDAY. LATEST WATER VAPOR SATELLITE IMAGERY PLACES THE SHORTWAVE OVER THE SOUTHERN PLAINS...WITH THE 00Z MODEL RUNS ALL DRIVING IT NORTHEAST ACROSS THE FORECAST AREA BY THIS EVENING. RELATIVELY WEAK FRONTOGENETIC FORCING VIA NAM12/RAP LOOKS RESPONSIBLE FOR THE CURRENT BAND OF LIGHT PCPN RUNNING NORTHWEST-SOUTHEAST FROM SOUTHERN MN THROUGH IA. THIS WILL CONTINUE TO LIFT NORTHEAST THROUGH THE MORNING. THE BULK OF THIS SYSTEM/S FORCING IS POST THIS BAND HOWEVER...WITH THE STRONG LOW LEVEL THERMODYNAMIC LIFT VIA WARM ADVECTION/ISENTROPIC UPGLIDE ON THE LEADING EDGE OF THE SHORTWAVE LIFTING ACROSS THE REGION FROM THE LATE MORNING THROUGH THE AFTERNOON. THE MODELS KEY ON THIS FORCING FOR THE SYSTEM/S MAIN PCPN BAND. PLENTY OF MOISTURE TO WORK WITH FOR EARLY FEB...WITH A STRONG PUSH OF 850 MB MOISTURE TRANSPORT ON THE NOSE OF 50 KT LOW LEVEL JET. PWS ARE NEARLY 300 PERCENT ABOVE NORMAL WITH SREF ANOMALIES AROUND +3. IN ADDITION...THE FRONTOGENETIC FORCING IS NEARLY UPRIGHT AT TIMES...PER NORTHEAST-SOUTHWEST RUNNING X-SECTIONS...AND THIS COUPLED WITH THE NOSE OF THE LOW LEVEL JET COULD RESULT IN SOME CONVECTION. A CRACK OR TWO OF THUNDER CAN/T BE RULED OUT...MOSTLY TO THE SOUTH. THE PCPN BAND MOVES NORTH OF THE FORECAST AREA BY 00Z...WITH THE STORM SYSTEM/S SFC LOW OVER NORTHERN IA BY THIS TIME. NAM/GFS CONTINUE TO INDICATE THAT A SMALLER AREA OF PCPN WILL DEVELOP WITH THE LOW...ASSOCIATED WITH UPPER LEVEL ENERGY BEING WRAPPED HARD AROUND THE STORM...AND SOME SFC TROUGHINESS RESULTING IN CONVERGENCE. THIS AREA OF ENHANCED QPF WOULD FALL ACROSS SOUTHEAST MN THIS EVENING...SHUFFLING ACROSS NORTHERN WI OVERNIGHT. ELSEWHERE...ENOUGH BROADSCALE LIFT WITH AMPLE SATURATION THAT AREAS OF LIGHT PCPN ARE LIKELY. WITH THE COLD FRONTAL PASSAGE IN THE EVENING...EXPECT A TRANSITION FROM RAIN TO SNOW. THE SNOW WILL LINGER ON MONDAY...WITH AN INVERTED SFC TROUGH HANGING WEST OF THE EASTWARD MOVING LOW...BITS OF UPPER LEVEL ENERGY...AND FAVORABLE LOW LEVEL LAPSE RATES HELPING SPARK THE SNOW. THE BETTER CHANCES WILL LIE MOSTLY ALONG AND NORTH OF I-90...WITH ADDITIONAL ACCUMULATIONS ON MONDAY OF AN INCH OR LESS. AS IT HAS APPEARED THE PAST FEW DAYS...THERE APPEARS TO BE 3 DIFFERENT PCPN PHASES WITH THIS STORM SYSTEM...OR PERHAPS 4 NOW. SFC OBS WITH THE FRONTOGENETIC PCPN BAND MOVING NORTHEAST INDICATES MOSTLY RAIN RIGHT NOW...ALTHOUGH THE CONVECTIVE NATURE WOULD SUGGEST THAT ANY HIGH RETURNS COULD BE...OR PERHAPS ARE MORE LIKELY TO BE...SLEET. RAP BUFKIT SOUNDINGS OVER NORTHEAST IA HAVE A 1-2 C WARM LAYER...WHICH GRADUALLY DEEPENS. THE ATMOSPHERE CONTINUES TO WARM...BUT AS IT DOES...THE CLOUDS LOSE THEIR ICE BEHIND THIS FIRST PCPN BAND. CURRENT IR/SATELLITE CLOUD TEMPS INDICATE THIS AS WELL. SO...COULD SEE A FREEZING RAIN/SLEET MIX CHANGE OVER TO FREEZING DRIZZLE FOR EARLY THIS MORNING...ALL SFC TEMP DEPENDENT OF COURSE. BUT REMEMBER - EVEN AS TEMPS WARM THROUGH THE DAY...ROAD TEMPS ARE COLDER...MOSTLY IN THE UPPER 20S...AND ICY SPOTS WILL DEVELOP IF THEY ARE UNTREATED. THE MAIN BAND OF PCPN...THE BAND THAT WILL BRING MOST OF THE QPF TO THE FORECAST AREA...IS EXPECTED TO DEVELOP JUST TO THE SOUTHWEST...MOVING NORTHEAST ACROSS THE REGION LATE MORNING/AFTERNOON. GOOD PUSH OF LOW LEVEL WARM AIR WITH THIS PCPN...GENERALLY 1-3 C AT MAX. THIS IS SUGGESTIVE OF ONLY PARTIAL MELTING...WHICH WOULD RESULT IN SLEET. HOWEVER...THE DEPTH OF THIS WARM LAYER EXCEEDS 3 KFT IN SOME LOCATIONS - WHICH COULD RESULT IN FULL MELTING. HOWEVER...THE TRACK OF THE SYSTEM KEEPS IT A BIT COLDER WEST OF THE MISSISSIPPI RIVER...EVIDENCED IN A WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS. NAM12 BUFKIT SOUNDINGS AT KRST WOULD FAVOR SNOW TO A SNOW/RAIN MIX...SFC TEMP DEPENDENT. NOT MUCH OF A DENDRITIC SNOW REGION...BUT ITS ISOTHERMAL AROUND 0 C FOR A FEW HOURS. WOULD EXPECT A WET SNOW WITH LOWER SNOW RATIOS. WILL HAVE TO TREND FROM WEST TO EAST AND SOUTH TO NORTH WITH PCPN TYPES. AFTER THIS BAND GOES THROUGH THE MODELS CONTINUE TO POINT TO A SHALLOWING OF THE CLOUD LAYER AND LOSS OF ICE AS A MID LEVEL DRY INTRUSION WORKS ACROSS THE REGION. DRIZZLE WOULD BE THE PCPN TYPE...OUTSIDE OF THE BAND OF PCPN ASSOCIATED WITH THE WRAP AROUND ENERGY. THAT SHOULD FALL AS SNOW. THE CLOUD LAYER DEEPENS AGAIN AND WELCOMES ICE BACK INTO THE PTYPE EQUATION EARLY THIS EVENING...POST THE SYSTEM/S COLD FRONT. AREAS OF LIGHT SNOW ARE LIKELY...WITH MINOR ACCUMULATIONS. THIS SNOW CONTINUES ON MONDAY...AS ALREADY MENTIONED. OVERALL...ITS A MESS. A LOT GOING ON WITH ONLY SMALL CHANGES IN HOW WARM IT GETS AND/OR DEPTH OF THE WARM LAYER HAVING A SIGNIFICANT IMPACT ON WHAT FALLS. THAT DOESN/T EVEN INCLUDE THE YES/NO ICE IN THE CLOUD QUESTION. IT DOES APPEAR THERE COULD BE A BIT MORE FROZEN PCPN THEN PREVIOUS FORECASTS HAVE INDICATED. EITHER WAY...THE WINTER WEATHER ADVISORY LOOKS GOOD AND WILL CONTINUE. .LONG TERM...WEDNESDAY THROUGH SATURDAY 230 AM CST SUN FEB 10 2013 MODELS REMAIN AT ODDS IN HOW TO HANDLE A NORTHWEST FLOW SHORTWAVE SLATED TO SPIN ACROSS THE REGION TOWARD THE END OF THE WORK WEEK. THE GFS MOVES THIS FEATURE IN WED NIGHT...KICKING IT EAST BY THU NIGHT. THE EC IS WEAKER WITH THIS SHORTWAVE...AND SLOWER...NOT MOVING IT UNTIL THU. IT MIGHT BE A BIT MORE SOUTH TOO. THE GEM SIDES MORE TOWARD THE GFS WITH STRENGTH AND POSITIONING...BUT IS SLOWER...ALSO MOVING IN OVERNIGHT WED. ALL PRODUCE QPF...MORE IN THE GEM/GFS...AND ALL WOULD BE SNOW. GOOD AMOUNT OF CONSISTENCY IN THE EC WITH POSITIONING...ALTHOUGH STRENGTH HAS VARIED. THE GFS HAS JUMPED AROUND. WILL LEAN ON AN EC/CONSENSUS SOLUTION FOR THIS TIME PERIOD. THE WEEKEND LOOKS COLDER AS A DEEPER UPPER LEVEL TROUGH IS CARVED OUT POST THE WED/THU SHORTWAVE. HIGHS IN THE TEENS WITH LOWS CLOSE TO ZERO LOOK REASONABLE. && .AVIATION...THROUGH 06Z MONDAY 1139 PM CST SAT FEB 9 2013 COMPLICATED FORECAST RUNNING THROUGH THE NEXT 24 HOURS AS A STORM SYSTEM APPROACHES FROM THE SOUTHWEST. CURRENTLY...IFR TO MVFR CEILINGS HAVE BEEN CLEARING FROM THE SOUTH ACROSS SOUTHERN WISCONSIN AND SOUTH CENTRAL MINNESOTA/NORTHEAST IOWA. CEILINGS COULD IMPROVE TO VFR EARLY SUNDAY MORNING...BUT THEN WILL LIKELY DROP DOWN AGAIN ONCE THE NEXT BAND OF PRECIPITATION MOVES IN. TIMING STILL LOOKS GOOD FOR THE FIRST WAVE OF SLEET/RAIN/FREEZING RAIN/SNOW TO MOVE IN AROUND 8Z AT RST AND 10Z AT LSE BUT THEN IT APPEARS THAT A DRY SLOT WILL COME IN BEHIND IT FOR A PERIOD. COULD SEE SOME DRIZZLE/FREEZING DRIZZLE AFTER THIS FIRST BAND COMES THROUGH...THOUGH NOT MANY OBSERVATIONS UPSTREAM ARE SHOWING ANY OF THAT. THE MAIN SLUG OF PRECIPITATION COMES IN LATER SUNDAY MORNING AND STILL LOOKS LIKE IT WILL BE A WINTRY MIX. LSE SHOULD BE MORE ON THE RAIN SIDE WHILE RST SHOULD BE MORE ON THE SNOW/SLEET SIDE. AFTER ANOTHER LULL AFTER THIS BAND MOVES THROUGH...SOME FOG SHOULD SET UP OUT AHEAD OF THE SURFACE LOW THAT WILL BRING A COLD FRONT INTO RST SUNDAY EVENING. && .HYDROLOGY... 230 AM CST SUN FEB 10 2013 MORNING RAIN...COUPLED WITH A FEW INCHES OF SNOW PACK...WILL LEAD TO RUNOFF INTO AREA WATERWAYS. NEARLY A FULL RELEASE AS GROUNDS ARE FROZEN. EXPECT SOME IN BANK RISES...BUT UNLESS EXPECTED AMOUNTS ARE SIGNIFICANTLY HIGHER...DON/T ANTICIPATE ANY WIDESPREAD FLOODING CONCERNS. THE POTENTIAL FOR ICE JAMS WILL HAVE TO BE MONITORED. && .ARX WATCHES/WARNINGS/ADVISORIES... 230 AM CST SUN FEB 10 2013 WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ032>034-041- 042-053>055-061. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS EVENING FOR WIZ017-029-043-044. MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ086-087-094- 095. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ079-088-096. IA...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ008>010-018- 019-029. WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ011-030. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION.....HALBACH HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 PM CST SAT FEB 9 2013 .SHORT TERM...TONIGHT INTO SUNDAY 849 PM CST SAT FEB 9 2013 MAIN FOCUS THIS EVENING IS ON THE PRECIPITATION TYPE TRENDS GOING INTO THE OVERNIGHT HOURS AND SUNDAY MORNING. BASED ON THE LATEST 6 HOURS OR SO OF RAP SOUNDINGS AND THE LATEST 10.00Z NAM SOUNDINGS...WILL BE MAKING SOME ADJUSTMENTS TO THE PRECIPITATION TYPES DUE TO WARM LAYER TEMPERATURES NOT LOOKING AS WARM ACROSS SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN. IN SE MN/WC WI... THE 10.01Z RAP AND 10.00Z NAM BUFKIT SOUNDINGS SUGGEST THAT THE WARM LAYER DOES NOT GET MUCH ABOVE THE 0-2C RANGE UNTIL AFTER 12Z SUNDAY. TOP DOWN APPROACH SAYS THAT THE THE MAIN PRECIPITATION TYPES WOULD BE SNOW AND SLEET STARTING TONIGHT BETWEEN 6-12Z. THEREFORE...WILL BE BUMPING UP THESE TOTALS A LITTLE BIT FOR THE OVERNIGHT PERIOD. THE THREAT FOR FREEZING RAIN LOOKS TO BE THE HIGHEST ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHERE THE WARM LAYER GETS INTO THE +3 TO +6C RANGE QUICKER THAN AREAS TO THE NORTH. HOWEVER...SURFACE TEMPERATURES ARE ALREADY HOVERING AROUND 30-32F IN THIS AREA...SO IMPACT MAY NOT BE TOO SIGNIFICANT THERE. AS THE RAIN/PRECIPITATION STARTS TO FALL...LATENT HEAT RELEASE WILL HELP TO PUSH THESE TEMPERATURES UP A FEW DEGREES AND THE SOUTHERLY WARM AIR ADVECTION WILL ALSO HELP TO KEEP TEMPERATURES ON A WARMING TREND OVERNIGHT INTO TOMORROW. THIS MEANS THAT THE PERIOD OF FREEZING RAIN WILL LIKELY BE BRIEF BEFORE IT GOES TO JUST REGULAR RAIN. OTHERWISE...THE TIMING OF THE SYSTEM STILL LOOKS ON TRACK WITH THE LAYOUT OF THE ADVISORIES AND WITH THE MIX OF PRECIPITATION TYPES...A WINTER WEATHER ADVISORY STILL LOOKS LIKE THE WAY TO GO FOR SOME OF THE SLICK SPOTS THAT WILL LIKELY FORM ON UNTREATED ROADS/SURFACES. THERE HAVE BEEN A FEW THUNDERSTORMS NOTED FROM NORTHWEST MISSOURI INTO EASTERN SOUTH DAKOTA THIS EVENING OUT IN THE LEADING PRECIPITATION BAND...BUT CONFIDENCE IS NOT HIGH ENOUGH THAT THESE WILL OCCUR INTO THE UPPER MISSISSIPPI RIVER VALLEY AS 10.01Z RAP 0-6KM MUCAPE REMAINS LESS THAN 100 J/KG THROUGH TOMORROW MORNING. STILL WOULD NOT BE SURPRISED TO HAVE SOME THUNDERSLEET OCCUR OVERNIGHT INTO TOMORROW MORNING GIVEN THE LARGE SCALE LIFT ASSOCIATED WITH THIS SYSTEM. .LONG TERM...TUESDAY THROUGH SATURDAY 238 PM CST SAT FEB 9 2013 NORTHWEST FLOW WILL SET UP BEHIND THE DEPARTING STORM SYSTEM MONDAY. THIS WILL ALLOW A SYSTEM TO DROP INTO THE UPPER MIDWEST THURSDAY. SOME DIFFERENCE ON HOW LONG THE LONG WAVE TROUGH WILL BE OVER THE UPPER MIDWEST AS THE 09.12Z ECMWF AND GEM HOLD ONTO IT AS IT CONNECTS TO ENERGY DROPPING INTO THE DESERT SOUTHWEST WHILE THE GFS IS A LITTLE MORE PROGRESSIVE. VERY LITTLE TIME SPENT DIAGNOSING THIS SYSTEM SO WILL LET THE MODEL CONSENSUS GRIDS RIDE WITH A CHANCE OF PRECIPITATION FROM THURSDAY INTO FRIDAY OR FRIDAY NIGHT. && .AVIATION...THROUGH 06Z MONDAY 1139 PM CST SAT FEB 9 2013 COMPLICATED FORECAST RUNNING THROUGH THE NEXT 24 HOURS AS A STORM SYSTEM APPROACHES FROM THE SOUTHWEST. CURRENTLY...IFR TO MVFR CEILINGS HAVE BEEN CLEARING FROM THE SOUTH ACROSS SOUTHERN WISCONSIN AND SOUTH CENTRAL MINNESOTA/NORTHEAST IOWA. CEILINGS COULD IMPROVE TO VFR EARLY SUNDAY MORNING...BUT THEN WILL LIKELY DROP DOWN AGAIN ONCE THE NEXT BAND OF PRECIPITATION MOVES IN. TIMING STILL LOOKS GOOD FOR THE FIRST WAVE OF SLEET/RAIN/FREEZING RAIN/SNOW TO MOVE IN AROUND 8Z AT RST AND 10Z AT LSE BUT THEN IT APPEARS THAT A DRY SLOT WILL COME IN BEHIND IT FOR A PERIOD. COULD SEE SOME DRIZZLE/FREEZING DRIZZLE AFTER THIS FIRST BAND COMES THROUGH...THOUGH NOT MANY OBSERVATIONS UPSTREAM ARE SHOWING ANY OF THAT. THE MAIN SLUG OF PRECIPITATION COMES IN LATER SUNDAY MORNING AND STILL LOOKS LIKE IT WILL BE A WINTRY MIX. LSE SHOULD BE MORE ON THE RAIN SIDE WHILE RST SHOULD BE MORE ON THE SNOW/SLEET SIDE. AFTER ANOTHER LULL AFTER THIS BAND MOVES THROUGH...SOME FOG SHOULD SET UP OUT AHEAD OF THE SURFACE LOW THAT WILL BRING A COLD FRONT INTO RST SUNDAY EVENING. && .HYDROLOGY... 238 PM CST SAT FEB 9 2013 RAINFALL FROM THE SYSTEM TONIGHT THROUGH SUNDAY COULD POSE SOME PROBLEMS FOR AREA STREAMS. THE GROUND IS FROZEN SO RUNOFF WILL NOT BE ABLE TO GO INTO THE GROUND AND WILL QUICKLY FIND ITS WAY INTO THE STREAMS. NOT EXPECTING HUGE AMOUNTS OF QPF...SO WOULD PRIMARILY THINK IN BANK RISES WOULD OCCUR. HOWEVER...SOME LOCALIZED HIGHER QPF AMOUNTS COULD LEAD TO MINOR FLOODING OF SMALLER STREAMS ALONG WITH SOME ICE JAM POTENTIAL. && .ARX WATCHES/WARNINGS/ADVISORIES... 238 PM CST SAT FEB 9 2013 WI...WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR WIZ032>034-041-042-053>055-061. WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST SUNDAY FOR WIZ017- 029-043-044. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR MNZ086-087-094-095. WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR MNZ079- 088-096. IA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR IAZ008>010-018-019-029. WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR IAZ011- 030. && $$ SHORT TERM...HALBACH LONG TERM...04 AVIATION...HALBACH HYDROLOGY....04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
246 AM MST TUE FEB 12 2013 .SHORT TERM...THE UPPER LEVEL TROUGH WILL MOVE SE OF THE AREA TODAY WITH THE FLOW ALOFT BECOMING MORE NLY AND THEN NNWLY TONIGHT. CROSS-SECTIONS SHOW SOME INCREASE IN MOISTURE OVER THE NRN MTNS BY TONIGHT HOWEVER WITH POOR LAPSE RATES ANY SNOW SHOULD BE VERY LIGHT AND CONFINED MAINLY TO ZN 31. OTHERWISE WILL KEEP THE REST OF THE RGN DRY THRU TONIGHT. AS FOR TEMPS 850-700 MB READINGS ONLY RISE A FEW DGREES TODAY SO WILL KEEP HIGHS IN THE UPPER 30S TO NEAR 40 ACROSS MOST OF NERN CO EXCEPT OVER THE FAR NERN CORNER WHERE LINGERING SNOW COVER MAY KEEP HIGHS IN THE LOWER 30S. .LONG TERM...MODELS HAVE FAIRLY WEAK NORTHWESTERLY FLOW ALOFT ON WEDNESDAY. IT INCREASES WEDNESDAY NIGHT AND BECOMES MORE WESTERLY. ON THURSDAY...A MEAN UPPER TROUGH CONTINUES DEVELOPING OVER EASTERN NORTH AMERICA WITH STRONG NORTHWESTERLY FLOW ON IT`S BACKSIDE RIGHT OVER COLORADO. THERE IS AN UPPER TROUGH WITH FAILRY DECENT SYNOPTIC SCALE ENERGY EMBEDDED IN THE FLOW ON THURSDAY INTO THURSDAY NIGHT. THIS USHERS IN A COLD FRONT WITH UPSLOPE BEHIND IT FOR THE PLAINS AND FOOTHILLS ON THURSDAY. THE UPSLOPE FLOW CONTINUES MUCH OF THURSDAY NIGHT. THE LOW LEVEL FLOW ON WEDNESDAY AND WEDNESDAY NIGHT IS MAINLY DOWNSLOPING. FOR MOISTURE...MODELS SHOW SOME IN THE MOUTNIANS...AND A BIT OVER THE PLAINS. MOISTURE INCREASES OVER ALL THE CWA WEDNESDAY NIGHT. BY THURSDAY IT IS PRETTY DEEP OVER ALL THE CWA...THIS CONTINUES THURSDAY NIGHT. THE QPF FIELDS HAVE A TAD OF MEASURABLE SNOWFALL OVER THE MOUNTAINS WEDNESDAY AND WEDNESDAY NIGHT. ON THURSDAY ...THE AMOUNTS IN THE MOUNTAINS INCREASE A BIT...AND THERE IS A TAD OVER THE MOST OF THE PLAINS BY AFTERNOON. THERE ARE HIGHER AMOUNTS THURSDAY NIGHT OVER THE FOOTHILLS AND IMMEDIATE PLAINS. THERE IS A BIT OVER MOST AREAS AFTER MIDNIGHT THURSDAY NIGHT... EXCEPT FOR THE NORTHEAST CORNER. FOR POPS...THERE IS ENOUGH MOISTURE AND OROGRAPHIC HELP TO KEEP "CHANCE"S OF SNOW IN THE HIGH MOUNTAINS WEDNESDAY INTO WEDNESDAY EVENING...THEN "LIKELY"S INTO THURSDAY EVENING. BY LATER THURSDAY INTO THURSDAY NIGHT...THE UPSLOPE BEHIND THE COLD FRONT...ALONG WITH A FAIRLY DECENT BRIEF SHOT OF SYNOPTIC SCALE ENERGY...AND MOISTURE...WILL GO WITH "CHANCE"S OVER MOST OF THE PLAINS AS WELL. FOR TEMPERATURES... WEDNESDAY`S HIGHS LOOK TO BE 3.0-4.5 C WARMER THAN TODAY`S. THURSDAY`S WILL BE 2-5 C COLDER THAN WEDNESDAY`S. THE MOS GUIDANCE WEDNESDAY AND THURSDAY HIGH TEMPERATURES FOR DENVER DIFFER CONSIDERABLY BETWEEN THE GFS AND NAM. THE GFS IS 12 DEGREES F WARMER BOTH DAYS. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY ...MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE CWA FRIDAY INTO EARLY SATURDAY. BY SATURDAY MIDDAY INTO THE EVENING AN UPPER RIDGE MOVES ACROSS THE FORECAST AREA WITH WEAK ZONAL FLOW. THE ZONAL FLOW INCREASES IN SPEED ON SUNDAY...THEN THE NEXT UPPER TROUGH IS PROGGED TO MOVE ACROSS COLORADO ON MONDAY. THE MOISTURE DECREASES RAPIDLY ON FRIDAY. BOTH THE GFS AND ECMWF SHOW A DRY WEEKEND WITH WARMING TEMPERATURES. BOTH ALSO SHOW PRETTY DEEP MOISTURE...EVEN UPSLOPE FOR THE PLAINS WITH THE MONDAY SYSTEM. && .AVIATION...WINDS ARE DRAINAGE EARLY THIS MORNING. LATEST HRRR AND RAP SHOW WINDS BECOMING MORE NNW BY 19Z AND THEN MORE NNE BY 23Z. BY EARLY EVENING EXPECT A LIGHT ELY COMPONENT WHICH WILL GRADUALLY BECOME DRAINAGE BY 04Z. OTHERWISE SHOULD HAVE VFR CONDITIONS TODAY AND TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....RJK AVIATION...RPK
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
430 AM EST TUE FEB 12 2013 .SYNOPSIS... 09Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR REGION ON THE NORTHERN PERIPHERY OF A BROAD EAST-WEST ORIENTED UPPER RIDGE EXTENDING FROM THE SOUTHERN GULF OF MEXICO TO THE FL STRAITS AND BAHAMAS. THIS RIDGE IS ALL THAT IS LEFT OF A ONCE MORE PROMINENT RIDGE ALONG THE EASTERN SEABOARD WHICH HAS BEEN BROKEN DOWN OVER THE PAST 24 HOURS BY STRONG SHORTWAVE ENERGY EJECTING EASTWARD OVER THE NORTHEAST STATES. THE OTHER FEATURE WITHIN THE LARGE SCALE FLOW PATTERN OF INTEREST IS A BROAD TROUGH IN PLACE OVER THE CENTRAL PLAINS AND WELL-ORGANIZED IMPULSE/SHORTWAVE EMBEDDED AT ITS BASE. THIS ENERGY WILL QUICKLY MOVE EASTWARD THROUGH THE LOWER MS AND SOUTHEASTERN STATES DURING THE NEXT 24-36 HOURS. 00Z KTBW SOUNDING SHOWED THE RESIDUAL INFLUENCE OF THE UPPER RIDGE TO OUR SOUTH WITH A SUBSIDENCE INVERSION AROUND 800MB. THIS DEEP LAYER SUPPRESSION WILL ONCE AGAIN HELP TO KEEP OUR FORECAST GENERALLY DRY AND WARM TODAY. AT THE SURFACE...RIDGE AXIS EXTENDS FROM THE BAHAMAS WESTWARD ACROSS THE FL PENINSULA TO THE FAR EASTERN GULF. THIS FEATURE LIES SOUTH OF A NOW QUASI-STATIONARY FRONTAL BOUNDARY ALIGNED FROM OFF THE AL/MS COAST TO APALACHEE BAY...AND THEN NORTHEAST TOWARD THE GA COAST. DEEP MOISTURE IS MOVING NORTHWARD AROUND THE SURFACE RIDGE AXIS AND RESULTING IN AREAS OF DENSE SEA-FOG OVER PORTIONS OF APALACHEE BAY. VERY DIFFICULT TO DETERMINE JUST HOW FAR EAST THIS FOG EXTENDS...AND WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG POTENTIAL REACH THE COASTAL WATERS OFF LEVY COUNTY THIS MORNING. FURTHER SOUTH...WINDS ARE RATHER LIGHT UNDER THE RIDGE AND LIKELY NOT SEEING MUCH IN THE WAY OF SEA-FOG. OBSERVATIONS SHOW RATHER THAT WE ARE SEEING AREAS OF SHALLOW RADIATION FOG OVER THE LAND AREAS OF THE NATURE COAST. THIS LAND BASED FOG IS BECOMING MORE WIDESPREAD WITH TIME AND A DENSE FOG ADVISORY WILL BE ISSUED FOR INLAND HILLSBOROUGH/EASTERN POLK COUNTIES NORTHWARD THROUGH THE NATURE COAST ZONES. THE SEA-FOG JUST TO OUR WEST MAY BECOME MORE OF AN ISSUE TONIGHT (TUESDAY NIGHT) AS FLOW VEERS MORE SOUTH AND EVEN SOUTHWEST WITH TIME. && .SHORT TERM (TODAY THROUGH THURSDAY)... TODAY/TONIGHT...ANOTHER WARM AND GENERALLY DRY DAY ON TAP FOR THE FLORIDA WEST COAST UNDERNEATH THE RESIDUAL UPPER RIDGING. STALLED FRONTAL BOUNDARY NEAR OR JUST SOUTH OF THE I-10 CORRIDOR EARLY THIS MORNING WILL BEGIN LIFTING SLOWLY NORTHWARD TODAY IN RESPONSE TO BOTH DIURNAL HEATING AND LOW ORGANIZATION OVER SOUTHERN LA. NOT OUT OF THE QUESTION THAT WE COULD SEE A FEW ISOLATED INSTABILITY SHOWERS ACROSS THE NATURE COAST IN CLOSEST PROXIMITY TO THE BOUNDARY...HOWEVER ANY COVERAGE WILL BE LOW AND OF MINIMAL IMPACT. ONCE AGAIN...GOOD DIURNAL MIXING ACTING ON A WARM LOW LEVEL COLUMN (850MB TEMPS 12-14C) WILL ALLOW TEMPS TO REACH THE UPPER 70S TO NEAR 80 NORTH AND THE LOWER 80S SOUTH. A FEW WARMER SPOTS WILL LIKELY SEE MID 80S SOUTH OF I-4. THE STRONG INLAND HEATING SHOULD FORCE AN ONSHORE WIND COMPONENT AT THE COAST THIS AFTERNOON AND KEEP TEMPS DOWN SEVERAL DEGREES AT THE BEACHES. UPPER LEVEL ENERGY BEGINS TO QUICKLY MOVE ALONG THE NORTHERN GULF COAST TONIGHT. SURFACE LOW LIFTS NORTH INTO AL WITH ITS TRAILING COLD FRONT PROGRESSING EAST TO THE FL PANHANDLE AND ADJACENT GULF WATERS. MAIN SYNOPTIC LIFT AND FRONTAL FORCING SHOULD HOLD TO OUR WEST MOST...IF NOT ALL OF THE NIGHT AND WILL KEEP RAIN CHANCES LOW. EVEN HIGHER DEWPOINT AIR STREAMING NORTHWARD WITHIN THE THERMAL RIDGE AHEAD OF THE FRONT WILL GIVE US A BETTER CHANCE OF SEA-FOG DEVELOPING ALONG THE NATURE COAST AND DOWN AS FAR SOUTH AS PINELLAS COUNTY. THIS POTENTIAL WILL NEED TO BE MONITORED CLOSELY THROUGH THE DAY. WEDNESDAY...SHORT WAVE ENERGY PASSES TO OUR NORTH...BUT IS CLOSE ENOUGH FOR A SWATH OF DECENT SYNOPTIC SUPPORT/QG FORCING TO SPREAD ACROSS THE AREA...ESPECIALLY FROM TAMPA BAY NORTHWARD. THIS ALONG WITH THE FRONTAL FOCUS SHOULD BE ENOUGH TO SUPPORT A BAND OF SHOWERS AND STORMS ACROSS THE CENTRAL AND NORTHERN PORTIONS OF THE AREA. THE TREND HAS BEEN TO SLOW THE ADVANCE OF THIS BAND WITH TIME...BUT OFTEN NWP GUIDANCE IS TOO SLOW WITH THESE TYPES OF FEATURES TO START WITH. WILL NOT GET TO DETAILED WITH THE TIMING AT THIS POINT...BUT WILL KEEP RAIN CHANCES HIGH FROM THE I-4 CORRIDOR NORTHWARD. FURTHER SOUTH...THE LATER ARRIVAL OF THE FRONTAL FOCUS WILL NOT COINCIDE WITH THE BEST KINEMATICS...AND WE ARE LIKELY TO SEE A MORE BROKEN BAND OF SHOWERS/ISOLATED STORMS INTO THE SOUTHERN ZONES DURING THE LATE AFTERNOON OR EVENING HOURS. WILL BE WATCHING FOR THE POTENTIAL OF A FEW STRONGER STORMS ON WEDNESDAY...ESPECIALLY NORTH OF TAMPA BAY. DEEP LAYER SHEAR IS NOT EXCEPTIONALLY HIGH...BUT IS SUFFICIENT TO SUPPORT ORGANIZED CONVECTION AND A FEW ENHANCED UPDRAFTS. THE QUESTION WILL BE WHETHER THE FLOW OFF THE COOLER SHELF WATERS PREVENTS ANY STORMS FROM BEING SURFACE BASED. WEDNESDAY NIGHT THROUGH THURSDAY...FRONT LAYS OUT OVER FAR SOUTHERN FL WEDNESDAY NIGHT...AND EXPECT TO SEE A BRIEF PERIOD WITH DRY CONDITIONS ACROSS THE ENTIRE AREA. THIS DOES NOT LOOK TO LAST LONG THOUGH...AS THE NEXT IMPULSE QUICKLY APPROACHES AND PROVIDES MORE DEEP LAYER LIFT. BY THURSDAY MORNING WE WILL ALSO FIND OUR AREA WITHIN THE FAVORABLE RIGHT ENTRANCE REGION OF A 140-150KT UPPER JET. GFS/ECMWF BOTH SHOW A SWATH OF GOOD UPPER LEVEL DIVERGENCE WITHIN THIS ZONE WHICH WILL ACT TO ENHANCE THE VERTICAL LIFT. TRICKY TO PIN-POINT WHERE ALL THE INGREDIENTS WILL COME TOGETHER BEST...BUT USING DEEP LAYER MOISTURE...IT WOULD APPEAR THE AREAS SOUTH OF TAMPA BAY WOULD SEE THE BEST CHANCES FOR SHOWERS/AREAS OF RAIN DEVELOPING THURSDAY. WILL GO WITH THIS SCENARIO FOR NOW...AND KEEP ANY SHOWERS MORE SCATTERED UP ACROSS THE I-4 CORRIDOR AND THEN ISOLATED TOWARD THE NORTHERN NATURE COAST ZONES. && .LONG TERM (THURSDAY NIGHT THROUGH NEXT MONDAY)... ONCE AGAIN THE GFS AND ECMWF ARE SIMILAR ENOUGH THROUGH MONDAY WITH REGARDS TO SYNOPTIC SCALE FEATURES BUT DIFFER ON SMALLER SCALE DETAILS. THROUGH FRIDAY NIGHT...A FRONTAL BOUNDARY WILL BE TO OUR SOUTH WITH A SHALLOW COOL AIRMASS IN PLACE OVER THE REGION. MID-LEVEL TROUGHING WILL REMAIN TO OUR WEST WITH SOUTHWESTERLY FLOW ALOFT. AT THE SAME TIME WE WILL BE SOUTH OF THE STRONG JET WHICH WILL PROVIDE ADDITIONAL LIFT FROM ABOVE. THESE FEATURES WILL COMBINE TO KEEP PARTLY TO MOSTLY CLOUDY SKIES OVER THE REGION WITH SOME TREND TOWARD CLEARING FROM NORTH TO SOUTH LATER FRIDAY AND FRIDAY NIGHT. OVER-RUNNING RAINS THURSDAY NIGHT WILL ALSO SLOWLY WIND DOWN FRIDAY AND FRIDAY NIGHT...BUT MODEL DIFFERENCES MAKE TIMING AND OVERALL RAIN CHANCES DIFFICULT TO PIN DOWN. BEST BET FOR RAIN IN THE EXTENDED PORTION OF THE FORECAST SHOULD COME THURSDAY NIGHT AND MAINLY OVER OUR SOUTHERN ZONES CLOSER TO THE INITIAL FRONTAL BOUNDARY. THE UPPER-LEVEL TROUGH WILL SHARPEN AND DIG SOUTHWARD INTO THE NORTHERN GULF ON SATURDAY...LOWERING HEIGHTS OVER THE REGION. THIS SHOULD BRING AND END TO THE OVER-RUNNING RAINS BUT THE 00Z ECMWF HAS BROUGHT SOME PRECIPITATION BACK INTO THE FORT MYERS REGION DURING THE AFTERNOON HOURS. THE GFS IS DRY AND WILL KEEP RAIN CHANCES BELOW 20 PERCENT FOR NOW. THE TROUGH AXIS WILL FINALLY SWING EAST OF FLORIDA SATURDAY NIGHT WHILE A SECOND PUSH OF MUCH COOLER AND DRIER AIR MOVES IN AT THE SURFACE. THE GFS AND ECMWF BOTH SHOW A BRIEF INTRUSION OF BELOW FREEZING TEMPERATURES AT 850MB SATURDAY NIGHT AND SUNDAY. THE COLD HIGH CENTER MOVES EASTWARD ACROSS THE NORTHERN GULF AND SETTLES DIRECTLY OVER NORTH FLORIDA SUNDAY NIGHT. IF SKIES ARE CLEAR...WE COULD BE LOOKING AT THE COLDEST NIGHT OF THE SEASON WITH TEMPERATURES DROPPING INTO THE MIDDLE OR UPPER 20S BY MONDAY MORNING OVER THE NATURE COAST AND NEAR-FREEZING TEMPERATURES TO THE SOUTH. SINCE THIS IS OUT AT DAY SEVEN...WILL PLAY IT A LITTLE CONSERVATIVE FOR NOW BUT STILL SHOW FREEZING TEMPERATURES NORTH. && .AVIATION... FOG WILL BRING MVFR/IFR VISIBILITIES TO PGD AND IFR/LIFR VISIBILITIES TO LAKELAND THROUGH 13 OR 14Z. OTHER TERMINALS COULD SEE SOME BRIEF MVFR VISIBILITIES THIS MORNING THEN VFR DURING THE AFTERNOON. FOG MAY AGAIN RESULT IN IFR CONDITIONS TONIGHT. && .MARINE... SURFACE HIGH PRESSURE WILL SLOWLY GIVE WAY THE NEXT 24 HOURS AS A COLD FRONT APPROACHES THE EASTERN GULF OF MEXICO FROM THE WEST. THIS FRONT WILL SHIFT THROUGH THE FORECAST WATERS WEDNESDAY AND WEDNESDAY EVENING WITH A WIND SHIFT TO THE NORTH IN ITS WAKE. PERIODS OF CAUTIONARY LEVEL WINDS ARE EXPECTED TONIGHT AND WEDNESDAY ALONG AHEAD OF THIS FRONT. AREAS OF SEA FOG AND REDUCED VISIBILITY ARE POSSIBLE TODAY OVER THE NORTHERN WATERS...MAINLY OFF THE COAST OF HERNANDO...CITRUS...AND LEVY COUNTIES. THIS FOG IS EXPECTED TO BECOME MORE WIDESPREAD TONIGHT INTO WEDNESDAY MORNING AND ALSO MAY EXPAND FURTHER SOUTH WITH TIME. MARINERS SHOULD MONITOR CONDITIONS CLOSELY UNTIL THE FRONT PASSES ON WEDNESDAY IN CASE MARINE DENSE FOG ADVISORIES BECOME NECESSARY. && .FIRE WEATHER... RELATIVE HUMIDITY WILL REMAIN ABOVE CRITICAL LEVELS THROUGH THE MIDWEEK PERIOD AS MOISTURE CONTINUES TO MOVE NORTH AHEAD OF A COLD FRONT. ONCE THE COLD FRONT MOVES THROUGH WEDNESDAY AND WEDNESDAY NIGHT...SOME DRIER AIR WILL ATTEMPT TO MOVE SOUTH INTO THE NATURE COAST ZONES...HOWEVER CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 66 79 61 / 0 10 60 40 FMY 83 67 84 64 / 0 10 20 30 GIF 83 64 83 58 / 10 10 50 40 SRQ 77 67 79 62 / 10 10 50 40 BKV 82 63 80 56 / 0 10 70 40 SPG 79 67 79 63 / 10 10 60 40 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...BEACH HAZARDS STATEMENT THROUGH THURSDAY EVENING FOR CHARLOTTE-LEE. BEACH HAZARDS STATEMENT THROUGH WEDNESDAY EVENING FOR SARASOTA. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1120 PM EST Mon Feb 11 2013 ...UPDATED FOR FOG... .NEAR TERM [through Tonight]... Latest satellite and local obs shows fog developing across region with the focus along and east of the frontal boundary, that is the SE third of our area. lamp, SREF and other guidance imply areas t widespread fog will develop rest of overnight. updated grids rest of tonight to insert patch dens west or and areas of dense fog along and east of frontal boundary. a dense fog advisory may be necessary soon. Convection continues to wind down during the late evening hours. Meanwhile, a large area of moderate rain with embedded thunderstorms was developing from C/S AL west into LA. This area of rain was roughly on the broad nose of a newly developed low- level moisture transport maximum - currently focused into coastal Louisiana and Mississippi. The RAP projects that the ribbon of strongest moisture transport should develop northeast into our area by around 03z, with roughly similar PWAT values. Therefore, we anticipate that rain - heavy at times, with embedded storms - will redevelop across much of the NW half to two-thirds of our area this evening. && .SHORT TERM [Tuesday through Wednesday Night]... A more pronounced mid-upper level trough - currently evident on water vapor loops over the Desert Southwest - will dig ESE into the Southern Plains on Tuesday, and then eject into the Ohio River Valley on Tuesday Night. This evolution will allow for surface cyclogenesis on Tuesday near coastal Louisiana, with the low passing northwest of our area through central Alabama on Tuesday Night. With stronger height falls and QG convergence to the west of us on Tuesday, we should see a lull in the rain during the day. The better chances of rain are expected to arrive from Tuesday Night into Wednesday with the main trailing cold front. Portions of our area are in a "Slight Risk" on the latest SPC SWODY2 outlook for the possibility of storms moving in later in the period (Tuesday evening or overnight). The local confidence grids and the SPC SREF calibrated severe probabilities both indicate about a 15-20% chance of severe storms in the western two-thirds of our area in the 12-hour period centered on 12z Wednesday. CIPS analogs from SLU show about 5-10% probabilities, with about half the analogs with at least one severe weather report in our area. The combination of all of these probabilistic outlooks are in fairly good agreement, and are consistent with some isolated severe storms late Tuesday Night. Mean model MLCAPE on the ECMWF, GFS, and CAM models looks to be around 500 j/kg overnight with about 60-70 knots of deep layer shear. && .LONG TERM [Thursday through Monday]... Quieter weather arrives with surface high pressure and increasing subsidence in the wake of the cold front on Thursday and Friday. An amplifying longwave trough in the eastern CONUS on the weekend may provide a shot of colder air, although details still vary from model-to-model, and run-to-run. && .Aviation...[Through 00z Wednesday] Prevailing IFR/LIFR conditions through daybreak followed by prevailing MVFR/IFR cigs/vsby for the remainder of the TAF period as an unsettled weather pattern remains across the Tri-state region. Scattered to numerous showers and thunderstorms will be common. && .MARINE... Unsettled weather pattern will remain through mid week with a chance of showers and thunderstorms, as well as breezy southerly winds each period. Winds will increase a bit ahead of a cold front Tuesday night and Wednesday, before switching to offshore on Thursday and diminishing into the weekend. && .FIRE WEATHER... An unsettled weather pattern with scattered to numerous showers and thunderstorms will continue at least through Wednesday. Drier conditions will return late in the week but we see no fire weather concerns at this time. && .HYDROLOGY... Significant rainfall has largely ended for this afternoon across the region. Observed and radar estimated rainfall totals show significant storm totals of 10 to 15 inches from Central Geneva County eastward through much of Houston County. Lower values of 5 to 8 inches were observed further east into parts of Southwestern Georgia in the last 24 hours. Given recent rains across Southeast Alabama and Southwest Georgia, little additional rainfall will be needed to cause flash flooding in these areas and a flash flood watch remains in effect through Tuesday morning. Higher end rainfall totals are expected once again on Tuesday evening through Wednesday across the area. Given the uncertainty with the exact placement of the heaviest rainfall with this next system, will delay any flash flood watches on this package. However, it is expected that additional flash flood watches will be needed across the area Tuesday night into Wednesday. Riverine flooding will become an increasing concern as local runoff is routed downstream from creeks and streams in Southeast Alabama. River gages north of a line from Enterprise Alabama to Abbeville Alabama appear to have crested with routed flow from these sites progressing down into the Choctawhatchee River system. Rises to near or in excess of minor flood stage is anticipated along the Choctawhatchee River from Geneva southward to Caryville into Friday given the current water already in the system. Flooding may also continue downriver toward Bruce but this would not occur until Saturday under present conditions. Rises on the Chipola River to minor flood stage can also be expected later this week as runoff progresses downstream from Southern Alabama. Additional riverine flooding, both in magnitude and coverage, will largely depend on the next 36 to 48 hours worth of rainfall. With soils already saturated in Southeast Alabama and a good portion of Southern Georgia, little additional rainfall will be absorbed there and will thus be converted into runoff, increasing river flood potential. River systems in South Central Georgia and the Florida Big Bend still have plenty of capacity and riverine flooding is not anticipated in these areas with this system. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 59 71 62 70 44 / 70 50 80 80 20 Panama City 60 71 62 66 46 / 80 50 80 70 20 Dothan 54 64 58 64 40 / 80 80 90 70 20 Albany 53 65 58 66 40 / 80 70 90 80 20 Valdosta 56 71 60 71 44 / 60 50 80 80 30 Cross City 61 77 61 74 48 / 20 30 60 70 30 Apalachicola 62 70 64 68 48 / 60 40 70 80 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FLASH FLOOD WATCH until 6 AM CST Tuesday for Central Walton- Holmes-Inland Walton-Jackson-Washington. GA...FLASH FLOOD WATCH until 7 AM EST Tuesday for Baker-Ben Hill- Calhoun-Clay-Dougherty-Early-Irwin-Lee-Miller-Quitman- Randolph-Seminole-Terrell-Tift-Turner-Worth. AL...FLASH FLOOD WATCH until 6 AM CST Tuesday for Coffee-Dale- Geneva-Henry-Houston. GM...None. && $$ BLOCK
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1103 PM EST Mon Feb 11 2013 ...UPDATED FOR AVIATION DISCUSSION... .NEAR TERM [through Tonight]... Convection continues to wind down during the late evening hours. Meanwhile, a large area of moderate rain with embedded thunderstorms was developing from C/S AL west into LA. This area of rain was roughly on the broad nose of a newly developed low- level moisture transport maximum - currently focused into coastal Louisiana and Mississippi. The RAP projects that the ribbon of strongest moisture transport should develop northeast into our area by around 03z, with roughly similar PWAT values. Therefore, we anticipate that rain - heavy at times, with embedded storms - will redevelop across much of the NW half to two-thirds of our area this evening. && .SHORT TERM [Tuesday through Wednesday Night]... A more pronounced mid-upper level trough - currently evident on water vapor loops over the Desert Southwest - will dig ESE into the Southern Plains on Tuesday, and then eject into the Ohio River Valley on Tuesday Night. This evolution will allow for surface cyclogenesis on Tuesday near coastal Louisiana, with the low passing northwest of our area through central Alabama on Tuesday Night. With stronger height falls and QG convergence to the west of us on Tuesday, we should see a lull in the rain during the day. The better chances of rain are expected to arrive from Tuesday Night into Wednesday with the main trailing cold front. Portions of our area are in a "Slight Risk" on the latest SPC SWODY2 outlook for the possibility of storms moving in later in the period (Tuesday evening or overnight). The local confidence grids and the SPC SREF calibrated severe probabilities both indicate about a 15-20% chance of severe storms in the western two-thirds of our area in the 12-hour period centered on 12z Wednesday. CIPS analogs from SLU show about 5-10% probabilities, with about half the analogs with at least one severe weather report in our area. The combination of all of these probabilistic outlooks are in fairly good agreement, and are consistent with some isolated severe storms late Tuesday Night. Mean model MLCAPE on the ECMWF, GFS, and CAM models looks to be around 500 j/kg overnight with about 60-70 knots of deep layer shear. && .LONG TERM [Thursday through Monday]... Quieter weather arrives with surface high pressure and increasing subsidence in the wake of the cold front on Thursday and Friday. An amplifying longwave trough in the eastern CONUS on the weekend may provide a shot of colder air, although details still vary from model-to-model, and run-to-run. && .Aviation...[Through 00z Wednesday] Prevailing IFR/LIFR conditions through daybreak followed by prevailing MVFR/IFR cigs/vsby for the remainder of the TAF period as an unsettled weather pattern remains across the Tri-state region. Scattered to numerous showers and thunderstorms will be common. && .MARINE... Unsettled weather pattern will remain through mid week with a chance of showers and thunderstorms, as well as breezy southerly winds each period. Winds will increase a bit ahead of a cold front Tuesday night and Wednesday, before switching to offshore on Thursday and diminishing into the weekend. && .FIRE WEATHER... An unsettled weather pattern with scattered to numerous showers and thunderstorms will continue at least through Wednesday. Drier conditions will return late in the week but we see no fire weather concerns at this time. && .HYDROLOGY... Significant rainfall has largely ended for this afternoon across the region. Observed and radar estimated rainfall totals show significant storm totals of 10 to 15 inches from Central Geneva County eastward through much of Houston County. Lower values of 5 to 8 inches were observed further east into parts of Southwestern Georgia in the last 24 hours. Given recent rains across Southeast Alabama and Southwest Georgia, little additional rainfall will be needed to cause flash flooding in these areas and a flash flood watch remains in effect through Tuesday morning. Higher end rainfall totals are expected once again on Tuesday evening through Wednesday across the area. Given the uncertainty with the exact placement of the heaviest rainfall with this next system, will delay any flash flood watches on this package. However, it is expected that additional flash flood watches will be needed across the area Tuesday night into Wednesday. Riverine flooding will become an increasing concern as local runoff is routed downstream from creeks and streams in Southeast Alabama. River gages north of a line from Enterprise Alabama to Abbeville Alabama appear to have crested with routed flow from these sites progressing down into the Choctawhatchee River system. Rises to near or in excess of minor flood stage is anticipated along the Choctawhatchee River from Geneva southward to Caryville into Friday given the current water already in the system. Flooding may also continue downriver toward Bruce but this would not occur until Saturday under present conditions. Rises on the Chipola River to minor flood stage can also be expected later this week as runoff progresses downstream from Southern Alabama. Additional riverine flooding, both in magnitude and coverage, will largely depend on the next 36 to 48 hours worth of rainfall. With soils already saturated in Southeast Alabama and a good portion of Southern Georgia, little additional rainfall will be absorbed there and will thus be converted into runoff, increasing river flood potential. River systems in South Central Georgia and the Florida Big Bend still have plenty of capacity and riverine flooding is not anticipated in these areas with this system. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 59 71 62 70 44 / 70 50 80 80 20 Panama City 60 71 62 66 46 / 80 50 80 70 20 Dothan 54 64 58 64 40 / 80 80 90 70 20 Albany 53 65 58 66 40 / 80 70 90 80 20 Valdosta 56 71 60 71 44 / 60 50 80 80 30 Cross City 61 77 61 74 48 / 20 30 60 70 30 Apalachicola 62 70 64 68 48 / 60 40 70 80 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FLASH FLOOD WATCH until 6 AM CST Tuesday for Central Walton- Holmes-Inland Walton-Jackson-Washington. GA...FLASH FLOOD WATCH until 7 AM EST Tuesday for Baker-Ben Hill- Calhoun-Clay-Dougherty-Early-Irwin-Lee-Miller-Quitman- Randolph-Seminole-Terrell-Tift-Turner-Worth. AL...FLASH FLOOD WATCH until 6 AM CST Tuesday for Coffee-Dale- Geneva-Henry-Houston. GM...None. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1204 AM EST TUE FEB 12 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 406 PM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...BROAD MID LEVEL TROUGH AND ASSOC CLOSED LOW ARE PROGRESSING STEADILY EAST OF THE UPPER GREAT LAKES. IN RESPONSE TO INCREASED RDGG FROM THE WEST...MODELS INDICATE INCREASING Q-VECT DIV/SUBSIDENCE SPREADING WEST TO EAST ACROSS FCST AREA INTO THIS EVENING. COMBINATION OF MQT RADAR...VIS SATELLITE AND AREA WEB CAMS SUGGEST ONLY LIGHT SNOW OR FLURRIES ACROSS THE CWA. THERE IS A BETTER BAND OF LES OVER WRN LAKE SUPERIOR AFFECTING NW WI THIS AFTERNOON WITH LIGHT TO MODERATE SNOW PER DLH RADAR. GIVEN THAT DEEPER MOISTURE WILL EXIT EAST TONIGHT WITH FLOW BCMG INCREASINGLY ANTICYCLONIC...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. AS A RESULT OF CONTINUED DIMINISHING TREND TO LES...EXPECT TO CANCEL REMAINING WINTER WX ADVISORIES OVER WRN COUNTIES ON THE AFTERNOON FCST ISSUANCE. EVEN IF BAND OVER NW WI DOES SWING INTO FAR WRN UPR MI...BELIEVE ANY INCREASE IN LES WILL BE SHORT-LIVED AND NOT BE WORTHY OF ADVISORY HEADLINE. LINGERING LIGHT LAKE EFFECT IS EXPECTED EAST TUE MORNING...BUT INCREASED DRYING/RDGG FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION SHOULD QUICKLY DIMINISH OR END LAKE EFFECT SNOW DURING THE DAY TUESDAY. EXPECT CLOUDS TO GENERALLY DIMINISH AS WELL THROUGH THE DAY WITH INCREASED RDGG. GENERALLY FOLLOWED A BLEND OF CONSENSUS MODEL GUIDANCE FOR LOW TEMPS TONIGHT AND HIGH TEMPS ON TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 406 PM EST MON FEB 11 2013 EXPECT NW FLOW ALOFT THROUGH MUCH OF THE LONG TERM PERIOD...WITH SEVERAL OPEN WAVES DIVING TOWARD THE UPPER GREAT LAKES. LAKE EFFECT SNOW SHOWERS OVER THE KEWEENAW PENINSULA...AND NEAR AND EAST OF MUNISING NEAR LAKE SUPERIOR WILL BE COMMON. THE NEXT SYSTEM TO INFLUENCE OUR WEATHER WILL BE IN THE FORM OF A SFC TROUGH EXTENDING FROM THE PARENT LOW OVER HUDSON BAY. THE TROUGH WILL SWEEP W-E ACROSS UPPER MI TUESDAY NIGHT...BEFORE EXITING TO EASTERN ONTARIO LATE WEDNESDAY MORNING. 850MB TEMPS OF -7 TO -10C. YET ANOTHER QUICK CLIPPER SYSTEM SET UP OVER CENTRAL ALBERTA AND SASKATCHEWAN TUESDAY NIGHT WILL QUICKLY CROSS LAKE WINNIPEG WEDNESDAY MORNING...AND PUSH INTO WESTERN LAKE SUPERIOR WEDNESDAY EVENING...THEN ACROSS CENTRAL UPPER MI/LAKE SUPERIOR BY 12Z THURSDAY...AND EASTERN UPPER MI AROUND 18Z. WHILE THE NAM/GFS/ECMWF/SREF SHOW A SIMILAR TRACK TO THE SFC LOW...THE 11/00Z CANADIAN IS APPROX 300MI SW OF THE CONSENSUS. WILL LIMIT THE USE OF THE 11/00Z CANADIAN FORECAST FOR WEDNESDAY THROUGH THURSDAY. SNOW AMOUNTS WEDNESDAY NIGHT THROUGH THURSDAY COULD ACCUMULATE 3 TO 6 INCHES OF LES FROM IWD UP THROUGH THE KEWEENAW PENINSULA...WITH SNOW TO LIQUID RATIOS AROUND 17:1. LIGHTER AMOUNTS OF 2 TO 5 INCHES WILL BE POSSIBLE NORTH CENTRAL...AND 1 TO 3 INCHES ELSEWHERE. WILL ADD THE MENTION OF LIGHT TO MODERATE SNOW WITH LAKE ENHANCEMENT FOR WEDNESDAY NIGHT THROUGH THURSDAY...BEFORE THE DGZ FALLS CLOSER TO THE SFC AS COLDER AIR PUSHES IN...LIMITING SIGNIFICANT ACCUMULATIONS. A WEAKENING SFC TROUGH WILL AGAIN LINGER ACROSS CENTRAL AND EASTERN LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY AS STRONGER HIGH PRESSURE SINKS ACROSS THE CENTRAL CANADA AND THE PLAINS STATES...WITH A RIDGE EDGING INTO WESTERN UPPER MI/LAKE SUPERIOR. THE 11/12Z GFS WAS A BIT STRONGER WITH WHAT THE ECMWF HAS AS AN OPEN WAVE PUSHING IN FROM THE NNW SATURDAY...ACCENTUATING THE SFC LOW OVER EASTERN LAKE SUPERIOR. EITHER WAY...LAKE EFFECT SNOW SHOWERS WILL BE LINGERING OVER CENTRAL AND EASTERN UPPER MI NEAR LAKE SUPERIOR. EXPECT LES TO PICK UP SIGNIFICANTLY THURSDAY AFTERNOON AND EVENING AS COLDER AIR FILTERS IN BEHIND THE EXITING LOW ON FAVORABLE NNW WINDS. 850MB TEMPS WILL FALL TO AROUND -17C OVER THE W HALF BY THE END OF THE DAY THURSDAY...WITH FURTHER COOLING TO -19 TO -20C THROUGH THE START OF THE WEEKEND. -22 TO -24C LOOKS TO BE THE COOLEST POINT...SATURDAY AFTERNOON. WHILE THE 11/06Z GFS AND 11/00Z ECMWF ARE PRETTY CONSISTENT UNTIL SATURDAY...THEY BEGIN TO DIVERGE SATURDAY AFTERNOON...WITH THE GFS DEVELOPING A LOW OVER THE CENTRAL PLAINS BECOMING OUT OF PHASE WITH THE REST OF THE AVAILABLE MODELS. THE GOOD NEWS IS THAT THE 11/12Z GFS LOOKS TO HAVE FIXED THIS POTENTIAL PROBLEM...AND ANOTHER POSSIBLE STORM TOWARD THE EAST COAST FOR THE UPCOMING WEEKEND. EXPECT A COOL RIDGE OF HIGH PRESSURE TO EDGE ACROSS THE UPPER GREAT LAKES FOR THE WEEKEND...AS AN ELONGATED TROUGH GAINS STEAM FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES ON SUNDAY. FOR MONDAY IT WILL BE A QUESTION AS TO IF THE SOUTHERN OR NORTHERN STREAM WINS OUT. AT THIS POINT THE 11/00Z ECMWF LOOKS TO BE STRONGER WITH THE SYSTEM AS A WHOLE...BUT WILL WAIT UNTIL THE TIME PERIOD BECOMES A BIT MORE CLEAR BEFORE LEANING TO ONE SOLUTION OVER ANOTHER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1203 AM EST TUE FEB 12 2013 MAINLY MVFR CONDITIONS ARE EXPECTED OVERNIGHT WITH CONTINUED MOIST NW FLOW AND MINOR LAKE EFFECT SNOW/FLURRIES IN NORTHERN UPPER MICHIGAN BEHIND THE DEPARTING LOW PRESSURE SYSTEM. MVFR CIGS COULD SCATTER LATE IN THE NIGHT AT IWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW UNDER DOWNSLOPING W TO NW WINDS. OTHERWISE...LOOK FOR MVFR CIGS TO SCT OUT AT BOTH KCMX AND KSAW BY LATE MORNING WITH INCREASED SUBSIDENCE AND RDGING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 406 PM EST MON FEB 11 2013 NW GALES OVER CENTRAL LAKE SUPERIOR AIDED BY PRES RISE MAX WILL DIMINISH BLO GALES BY LATE EVENING AS NW GRADIENT WEAKENS DUE TO LOW DEPARTING EAST AND RDG BUILDING IN FM WEST. HIGH PRES RDG AXIS MOVG EAST ACROSS THE LAKE WILL KEEP WINDS AOB 20 KTS OVER EAST HALF OF LAKE SUPERIOR. WEST HALF AND FAR NCNTRL LAKE SHOULD SEE AN INCREASE IN SW WINDS TUE AFTERNOON TO 25 KTS WITH TIGHTENING GRAD ON BACKSIDE OF RDG AXIS. A WEAK TROUGH STRETCHING FROM HUDSON BAY THROUGH THE UPPER GREAT LAKES TUESDAY NIGHT WILL BE REINFORCED BY ANOTHER LOW FROM THE NORTHWEST...THAT WILL PUSH ACROSS LAKE SUPERIOR/UPPER MI THURSDAY MORNING INTO THURSDAY AFTERNOON...BEFORE QUICKLY EXITING INTO SOUTERN ONTARIO AND QUEBEC THURSDAY AFTERNOON/EVENING. A FEW N GALE FORCE GUSTS TO 35KTS WILL BE POSSIBLE THURSDAY AFTERNOON ACROSS MAINLY CENTRAL LAKE SUPERIOR...WITH HEAVY FREEZING SPRAY OVER MUCH OF THE LAKE THURSDAY NIGHT. WHILE A WEAKENING TROUGH OF LOW PRESSURE REMAINS OVER EASTERN LAKE SUPERIOR...HIGH PRESSURE WILL SLOWLY BUILD IN FROM THE WEST THORUGH SATURDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...JLB MARINE...VOSS/KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1230 PM CST SUN FEB 10 2013 .UPDATE... UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW. && .PREV DISCUSSION.../ISSUED AT 430 AM CST SUN FEB 10 2013/ THE POWERFUL STORM WILL BRING WINTER WEATHER ACROSS THE REGION TODAY...WITH A BAND OF HEAVY SNOW WITH CONVECTIVE ELEMENTS EXPECTED TO DEVELOP THIS MORNING AND TRAVERSE THE REGION AS IT MOVES NORTHWARD TOWARDS LAKES SUPERIOR. SNOW WILL CONTINUE ACROSS THE WEST THROUGHOUT THE DAY...BUT THE REST OF THE REGION SHOULD SEE A BREAK DURING THE AFTERNOON HOURS. SOME ADDITIONAL SNOW IS EXPECTED OVERNIGHT...WITH BLIZZARD CONDITIONS DEVELOPING LATER TONIGHT ACROSS THE MINNESOTA RIVER VALLEY. LOOKING AHEAD...COOLER WEATHER WILL SETTLE IN FOR THE UPCOMING WEEK...WITH NO SIGNIFICANT PRECIPITATION EXPECTED. TODAY THROUGH MONDAY...AS OF EARLY THIS MORNING...THE WELL ADVERTISED WINTER STORM WAS TAKING SHAPE ACROSS THE CENTRAL CONUS. IR IMAGERY TOGETHER WITH RAP13 SURFACE ANALYSIS PLACED THE SURFACE LOW ACROSS SOUTH CENTRAL NEBRASKA...WITH THREE DISTINCT AREAS OF COLD CLOUD TOPS FANNING OUT ACROSS THE UPPER MIDWEST. OVER THE NEXT 12 HOURS...ISENTROPIC LIFT WILL INCREASE ACROSS THE CWA...WITH A FRONTOGENETIC CIRCULATION IN THE H700-500 LAYER AIDING IN THE ASCENT. A CROSS SECTION FROM OMAHA THROUGH DULUTH DEPICT THIS VERTICAL MOTION. PERHAPS MOST IMPORTANTLY THE CROSS SECTION ALSO SHOWS UPRIGHT INSTABILITY VIA THE THETA_E LINES WITHIN THIS LAYER ON THE LEADING EDGE OF THE DRY SLOT. THIS IS A TEXTBOOK SETUP FOR THUNDERSNOW...AND THIS ELEVATED INSTABILITY IS CONFIRMED BY ELEVATED CAPE VALUES OF 50 TO 100J/KG VIA THE SREF/NAM/GFS BUFR SOUNDINGS AT KFRM/KRWF/KMSP/KEAU. THEREFORE DESPITE THE ABSENCE OF A DEEP COLD LAYER...INCLUDED SLEET IN THE GRIDS TO TARGET THE POSSIBILITY OF SOME GRAUPEL WITH THE CONVECTIVE ELEMENTS. THE LAST FEW RUNS OF THE HRRR HAVE A GOOD HANDLE ON THE RAPID DEVELOPMENT OF AN AREA OF PRECIP THAT IS NOW LOCATED OVER EASTERN NEBRASKA. TRIED TO TIME THIS BAND OF HEAVY SNOW IN THE HOURLY WEATHER GRIDS. IT SHOULD ARRIVE AT FAIRMONT BY 11/12Z...AND REACH THE METRO AREA AND ST CLOUD AROUND 15/16Z...AND IMPACT RICE LAKE/EAU CLAIRE AROUND 16/17Z. FURTHER WEST MODERATE TO HEAVY SNOW IS EXPECTED MOST OF THE DAY AS A TROWEL...SEEN IN THE H500-700 THICKNESS...DEVELOPS ACROSS CENTRAL MINNESOTA. AS THE CYCLONE CONTINUES TO OCCLUDE...THE MEDIUM RANGE AND HIRES MODELS ALL DEVELOP A SECOND AREA OF PRECIP AHEAD OF THE H500MB VORT MAX SUNDAY EVENING THAT LAGS THE SURFACE LOW AND TRACKS FROM ROUGHLY ALBERT LEA...THROUGH RED WING...AND LADYSMITH. THIS WILL DROP ADDITIONAL SNOW FALL ACROSS SOUTHERN MINNESOTA...WHICH COULD SET THE STAGE FOR BLIZZARD CONDITIONS EXTENDING AS FAR SOUTH AS I-90 SUNDAY NIGHT THROUGH MONDAY. BUFR FORECAST SOUNDINGS AT FAIRMONT FROM BOTH THE GFS AND NAM SHOW DIFFERENTIAL COLD AIR ADVECTION DESTABILIZING THE BOUNDARY LAYER SUNDAY NIGHT...WITH WINDS OF 40 TO 45KTS ATOP THE MIXED LAYER...AS WELL AS SATURATION AND WEAK LIFT WITHIN THE DEEP DENDRITIC ZONE. IF THE SNOWFALL FORECAST PANS OUT ACROSS SOUTHERN MINNESOTA TODAY AND THE DITCHES ARE FULL...THAN HAVE HIGH CONFIDENCE THAT THE BLIZZARD WARNING WILL NEED TO BE EXTENDED SOUTH LASTING THROUGH MONDAY AFTERNOON. GIVEN THE CURRENT COMPLEX HEADLINE SITUATION...HAVE OPTED TO JUST EXTEND THE WINTER WEATHER ADVISORY OUT IN TIME THROUGH MONDAY AFTERNOON SINCE THE BLIZZARD CONDITIONS WOULDN/T DEVELOP UNTIL SUNDAY NIGHT. MONDAY NIGHT THROUGH FRIDAY...NORTHWEST FLOW WILL DEVELOP ACROSS THE REGION WITH A SURFACE HIGH BUILDING OVER THE UPPER MIDWEST IN THE WAKE OF THE STORM. LEE SIDE WARMING OVER THE CANADIAN PLAINS WILL KEEP THE COLDEST AIR ACROSS HUDSON BAY. A CLIPPER SYSTEM WILL MOVE ACROSS THE REGION MID WEEK AND BRING SOME LIGHT SNOW. POPS WILL LIKELY HAVE TO BE ADJUSTED UP FOR THIS SYSTEM IF IT REMAINS ON COURSE. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW BEHIND THIS CLIPPER...WITH SUB ZERO LOW TEMPERATURES POSSIBLE BY THE END OF THE WEEK. && .AVIATION.../18Z TAF ISSUANCE/ SIGNIFICANT WINTER STORM OVER THE AREA CONTINUES. ALL MN TAF SITES HAVE CHANGED OVER TO SNOW OF VARYING INTENSITIES WHILE THE WI TAF SITES ARE STILL DEALING WITH THE VARIED WINTRY P-TYPES. WILL LOOK FOR THEIR CHANGEOVER TO OCCUR BY AROUND 20Z. NEXT COMPLICATION COMES WITH THE DRY SLOT MOVING UP FROM SRN MN. THIS WILL ALLOW SNOWFALL TO TAPER OFF TO -SN OR SHSN...IF NOT NOTHING...FOR A 3-4 HR PERIOD BETWEEN ABOUT 21Z-00Z. POSSIBLE TO SEE SOME -FZDZ AS THE SNOW COMES TO AN END...BUT ICING WILL BE VERY MINIMAL...IF ANYTHING. WHEN SNOW RESUMES LATER THIS EVENING...EXPECTING IT TO REMAIN ON THE LIGHT SIDE...VARYING BETWEEN SHSN AND -SN. THERE STILL MAY BE SOME LIGHT ACCUMULATIONS WITH THIS LATER SNOW BUT THE BULK OF ACCUMULATIONS FROM THIS SYSTEM OVERALL WILL HAVE OCCURRED FROM THIS MRNG THRU MID-AFTN. AS THE LOW PRES CENTER SHIFTS NE ACRS THE AREA THIS EVENING...WINDS WILL SWING ARND THE COMPASS FROM E TO S TO NW AND REMAIN NW THRU TMRW. IN ADDITION...THE TIGHT PRES GRADIENT FOLLOWING THIS LOW WILL MAKE FOR A STRONG INCRS IN WIND SPEEDS TNGT THRU TMRW...SUCH THAT BLSN WILL BE A CONCERN FOR WRN TAF SITES THRU THE NIGHT. CONDITIONS TRY TO IMPROVE LATE DAY TMRW WHEN THE SNOWFALL WILL BE NOTICEABLY LIGHTER AND WINDS START TO DROP OFF. KMSP...P-TYPE HAS CHANGED OVER TO PREDOMINANTLY SNOW AND THIS IS EXPECTED TO REMAIN AS SUCH FOR THE DURATION. THE MAIN EXCEPTION IS WHEN THE DRY SLOT...CURRENTLY FROM WRN THRU SERN MN...SHIFTS NWD OVER THE TWIN CITIES. AS THE -SN DIMINISHES...THERE MAY BE A BRIEF PERIOD OF -FZDZ WITH VERY LIMITED ICING. THE PRECIP IS THEN EXPECTED TO TAKE A 2-3 HR BREAK BETWEEN 20Z-21Z THRU 23Z-00Z. THERE STILL COULD BE SOME FLURRIES DURG THIS TIME...BUT NOT ANYWHERE NEAR THE INTENSITY SEEN EARLIER TDA. -SN WILL THEN RESUME THIS EVENING AND CONTINUE THRU MOST OF THE NIGHT...POSSIBLY BECOMING BLSN CLOSE TO DAYBREAK AS STRONG NW WINDS OVER WRN MN SHIFT INTO CENTRAL MN. CONDS WILL THEN TRY TO IMPROVE MID-TO-LATE DAY TMRW. /OUTLOOK FOR KMSP/ LATE MON...MVFR WITH -SN. NW WINDS 18G30KTS. TUE...VFR. W WINDS 5 TO 10 KTS. WED...VFR. MVFR WITH CHC -SN LATE. SW WINDS 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR BLUE EARTH- FARIBAULT-FREEBORN-LE SUEUR-MARTIN-RICE-SCOTT-STEELE-WASECA- WATONWAN. WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-POPE- REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. BLIZZARD WARNING FROM 9 PM THIS EVENING TO 6 PM CST MONDAY FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET- POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR CARVER-MCLEOD- MEEKER-STEARNS-TODD-WRIGHT. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR ANOKA-BENTON- CHISAGO-HENNEPIN-ISANTI-KANABEC-MILLE LACS-MORRISON-RAMSEY- SHERBURNE-WASHINGTON. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR DAKOTA-GOODHUE. WI...WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR BARRON-POLK-RUSK- ST. CROIX. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CHIPPEWA-DUNN- EAU CLAIRE-PEPIN-PIERCE. && $$ JPC
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
619 AM CST SUN FEB 10 2013 .UPDATE...UPDATED AVIATION DISCUSSION BELOW. && .PREV DISCUSSION.../ISSUED AT 430 AM CST SUN FEB 10 2013/ THE POWERFUL STORM WILL BRING WINTER WEATHER ACROSS THE REGION TODAY...WITH A BAND OF HEAVY SNOW WITH CONVECTIVE ELEMENTS EXPECTED TO DEVELOP THIS MORNING AND TRAVERSE THE REGION AS IT MOVES NORTHWARD TOWARDS LAKES SUPERIOR. SNOW WILL CONTINUE ACROSS THE WEST THROUGHOUT THE DAY...BUT THE REST OF THE REGION SHOULD SEE A BREAK DURING THE AFTERNOON HOURS. SOME ADDITIONAL SNOW IS EXPECTED OVERNIGHT...WITH BLIZZARD CONDITIONS DEVELOPING LATER TONIGHT ACROSS THE MINNESOTA RIVER VALLEY. LOOKING AHEAD...COOLER WEATHER WILL SETTLE IN FOR THE UPCOMING WEEK...WITH NO SIGNIFICANT PRECIPITATION EXPECTED. TODAY THROUGH MONDAY...AS OF EARLY THIS MORNING...THE WELL ADVERTISED WINTER STORM WAS TAKING SHAPE ACROSS THE CENTRAL CONUS. IR IMAGERY TOGETHER WITH RAP13 SURFACE ANALYSIS PLACED THE SURFACE LOW ACROSS SOUTH CENTRAL NEBRASKA...WITH THREE DISTINCT AREAS OF COLD CLOUD TOPS FANNING OUT ACROSS THE UPPER MIDWEST. OVER THE NEXT 12 HOURS...ISENTROPIC LIFT WILL INCREASE ACROSS THE CWA...WITH A FRONTOGENETIC CIRCULATION IN THE H700-500 LAYER AIDING IN THE ASCENT. A CROSS SECTION FROM OMAHA THROUGH DULUTH DEPICT THIS VERTICAL MOTION. PERHAPS MOST IMPORTANTLY THE CROSS SECTION ALSO SHOWS UPRIGHT INSTABILITY VIA THE THETA_E LINES WITHIN THIS LAYER ON THE LEADING EDGE OF THE DRY SLOT. THIS IS A TEXTBOOK SETUP FOR THUNDERSNOW...AND THIS ELEVATED INSTABILITY IS CONFIRMED BY ELEVATED CAPE VALUES OF 50 TO 100J/KG VIA THE SREF/NAM/GFS BUFR SOUNDINGS AT KFRM/KRWF/KMSP/KEAU. THEREFORE DESPITE THE ABSENCE OF A DEEP COLD LAYER...INCLUDED SLEET IN THE GRIDS TO TARGET THE POSSIBILITY OF SOME GRAUPEL WITH THE CONVECTIVE ELEMENTS. THE LAST FEW RUNS OF THE HRRR HAVE A GOOD HANDLE ON THE RAPID DEVELOPMENT OF AN AREA OF PRECIP THAT IS NOW LOCATED OVER EASTERN NEBRASKA. TRIED TO TIME THIS BAND OF HEAVY SNOW IN THE HOURLY WEATHER GRIDS. IT SHOULD ARRIVE AT FAIRMONT BY 11/12Z...AND REACH THE METRO AREA AND ST CLOUD AROUND 15/16Z...AND IMPACT RICE LAKE/EAU CLAIRE AROUND 16/17Z. FURTHER WEST MODERATE TO HEAVY SNOW IS EXPECTED MOST OF THE DAY AS A TROWEL...SEEN IN THE H500-700 THICKNESS...DEVELOPS ACROSS CENTRAL MINNESOTA. AS THE CYCLONE CONTINUES TO OCCLUDE...THE MEDIUM RANGE AND HIRES MODELS ALL DEVELOP A SECOND AREA OF PRECIP AHEAD OF THE H500MB VORT MAX SUNDAY EVENING THAT LAGS THE SURFACE LOW AND TRACKS FROM ROUGHLY ALBERT LEA...THROUGH RED WING...AND LADYSMITH. THIS WILL DROP ADDITIONAL SNOW FALL ACROSS SOUTHERN MINNESOTA...WHICH COULD SET THE STAGE FOR BLIZZARD CONDITIONS EXTENDING AS FAR SOUTH AS I-90 SUNDAY NIGHT THROUGH MONDAY. BUFR FORECAST SOUNDINGS AT FAIRMONT FROM BOTH THE GFS AND NAM SHOW DIFFERENTIAL COLD AIR ADVECTION DESTABILIZING THE BOUNDARY LAYER SUNDAY NIGHT...WITH WINDS OF 40 TO 45KTS ATOP THE MIXED LAYER...AS WELL AS SATURATION AND WEAK LIFT WITHIN THE DEEP DENDRITIC ZONE. IF THE SNOWFALL FORECAST PANS OUT ACROSS SOUTHERN MINNESOTA TODAY AND THE DITCHES ARE FULL...THAN HAVE HIGH CONFIDENCE THAT THE BLIZZARD WARNING WILL NEED TO BE EXTENDED SOUTH LASTING THROUGH MONDAY AFTERNOON. GIVEN THE CURRENT COMPLEX HEADLINE SITUATION...HAVE OPTED TO JUST EXTEND THE WINTER WEATHER ADVISORY OUT IN TIME THROUGH MONDAY AFTERNOON SINCE THE BLIZZARD CONDITIONS WOULDN/T DEVELOP UNTIL SUNDAY NIGHT. MONDAY NIGHT THROUGH FRIDAY...NORTHWEST FLOW WILL DEVELOP ACROSS THE REGION WITH A SURFACE HIGH BUILDING OVER THE UPPER MIDWEST IN THE WAKE OF THE STORM. LEE SIDE WARMING OVER THE CANADIAN PLAINS WILL KEEP THE COLDEST AIR ACROSS HUDSON BAY. A CLIPPER SYSTEM WILL MOVE ACROSS THE REGION MID WEEK AND BRING SOME LIGHT SNOW. POPS WILL LIKELY HAVE TO BE ADJUSTED UP FOR THIS SYSTEM IF IT REMAINS ON COURSE. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW BEHIND THIS CLIPPER...WITH SUB ZERO LOW TEMPERATURES POSSIBLE BY THE END OF THE WEEK. && .AVIATION.../12Z TAF ISSUANCE/ THE WINTER STORM IS NOW UNDERWAY WITH ONE BATCH OF PRECIP PUSHING THROUGH ALL THE TAF SITES EARLIER...WITH A MORE INTENSE ROUND NOW DEVELOPING ACROSS SWRN MN AND WRN IA. THIS BATCH WILL BRING A PERIOD OF HEAVY PRECIPITATION TO MUCH OF THE AREA LATE THIS MORNING AND EARLY AFTERNOON. ISOLATED THUNDERSTORMS HAVE ALREADY BEEN DEVELOPING WITHIN THIS BAND OVERNIGHT...AND THINK THAT TREND WILL CONTINUE AS IT SWINGS THROUGH. IT SHOULD REMAIN MOSTLY SNOW NORTH OF A LINE FROM KDXX...TO KMSP...AND KRNH. SOUTH OF THAT LINE A WINTRY MIX IS EXPECTED. FOLLOWING THAT ROUND...OCCASIONAL LIGHT SNOW OR PATCHY DRIZZLE WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD WITH THE STEADIEST AND HEAVIEST SNOW IMPACTING AXN...STC... AND POSSIBLY RWF INTO MONDAY MORNING. THERE WILL BE ANOTHER AREA WITH ENHANCED SNOWFALL FOR A FEW HOURS THIS EVENING JUST BEHIND THE LOW ITSELF WHICH SHOULD BRING MODERATE SNOW FROM KFRM...TO KRGX AND KEAU. KMSP AND KRNH MAY ALSO BE IMPACTED AND INDICATED SO IN THE TAF. BLIZZARD CONDITIONS WILL DEVELOP THIS EVENING AS WINDS STRENGTHEN. GUSTS TO 35+ KTS APPEAR LIKELY WEST OF KAXN AND INCLUDING KRWF. TOWARD THE END OF THE PERIOD...SOME OF THE STRONGER WINDS WILL SPREAD TO THE EASTERN TAF SITES. KMSP...FAIRLY HIGH CONFIDENCE IN A PERIOD OF HEAVY SNOW AND VICINITY TS LATE THIS MORNING AS THE MAIN BAND OF PRECIPITATION INTENSIFIES. SNOW RATES OF 1 TO 2 INCHES PER HOUR ARE PROBABLE. AFTER 18 OR 19Z...OCCASIONAL LIGHT SNOW WILL CONTINUE UNTIL THE LOW PASSES AT WHICH POINT ANOTHER BATCH OF HEAVIER SNOW COULD FALL EARLY THIS EVENING. MOST OF THE MODELS KEEP IT JUST SOUTH OF THE TERMINAL...BUT IT BEARS WATCHING. /OUTLOOK FOR KMSP/ LATE MON...MVFR WITH -SN. NW WINDS 18G30KTS. TUE...VFR. W WINDS 5 TO 10 KTS. WED...VFR. MVFR WITH CHC -SN LATE. SW WINDS 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR BLUE EARTH- FARIBAULT-FREEBORN-LE SUEUR-MARTIN-RICE-SCOTT-STEELE-WASECA- WATONWAN. WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-POPE- REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. BLIZZARD WARNING FROM 9 PM THIS EVENING TO 6 PM CST MONDAY FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET- POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR CARVER-MCLEOD- MEEKER-STEARNS-TODD-WRIGHT. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR ANOKA-BENTON- CHISAGO-HENNEPIN-ISANTI-KANABEC-MILLE LACS-MORRISON-RAMSEY- SHERBURNE-WASHINGTON. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR DAKOTA-GOODHUE. WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CHIPPEWA-DUNN- EAU CLAIRE-PEPIN-PIERCE. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR BARRON-POLK-RUSK- ST. CROIX. && $$ JRB/BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
430 AM CST SUN FEB 10 2013 .DISCUSSION... THE POWERFUL STORM WILL BRING WINTER WEATHER ACROSS THE REGION TODAY...WITH A BAND OF HEAVY SNOW WITH CONVECTIVE ELEMENTS EXPECTED TO DEVELOP THIS MORNING AND TRAVERSE THE REGION AS IT MOVES NORTHWARD TOWARDS LAKES SUPERIOR. SNOW WILL CONTINUE ACROSS THE WEST THROUGHOUT THE DAY...BUT THE REST OF THE REGION SHOULD SEE A BREAK DURING THE AFTERNOON HOURS. SOME ADDITIONAL SNOW IS EXPECTED OVERNIGHT...WITH BLIZZARD CONDITIONS DEVELOPING LATER TONIGHT ACROSS THE MINNESOTA RIVER VALLEY. LOOKING AHEAD...COOLER WEATHER WILL SETTLE IN FOR THE UPCOMING WEEK...WITH NO SIGNIFICANT PRECIPITATION EXPECTED. TODAY THROUGH MONDAY...AS OF EARLY THIS MORNING...THE WELL ADVERTISED WINTER STORM WAS TAKING SHAPE ACROSS THE CENTRAL CONUS. IR IMAGERY TOGETHER WITH RAP13 SURFACE ANALYSIS PLACED THE SURFACE LOW ACROSS SOUTH CENTRAL NEBRASKA...WITH THREE DISTINCT AREAS OF COLD CLOUD TOPS FANNING OUT ACROSS THE UPPER MIDWEST. OVER THE NEXT 12 HOURS...ISENTROPIC LIFT WILL INCREASE ACROSS THE CWA...WITH A FRONTOGENETIC CIRCULATION IN THE H700-500 LAYER AIDING IN THE ASCENT. A CROSS SECTION FROM OMAHA THROUGH DULUTH DEPICT THIS VERTICAL MOTION. PERHAPS MOST IMPORTANTLY THE CROSS SECTION ALSO SHOWS UPRIGHT INSTABILITY VIA THE THETA_E LINES WITHIN THIS LAYER ON THE LEADING EDGE OF THE DRY SLOT. THIS IS A TEXTBOOK SETUP FOR THUNDERSNOW...AND THIS ELEVATED INSTABILITY IS CONFIRMED BY ELEVATED CAPE VALUES OF 50 TO 100J/KG VIA THE SREF/NAM/GFS BUFR SOUNDINGS AT KFRM/KRWF/KMSP/KEAU. THEREFORE DESPITE THE ABSENCE OF A DEEP COLD LAYER...INCLUDED SLEET IN THE GRIDS TO TARGET THE POSSIBILITY OF SOME GRAUPEL WITH THE CONVECTIVE ELEMENTS. THE LAST FEW RUNS OF THE HRRR HAVE A GOOD HANDLE ON THE RAPID DEVELOPMENT OF AN AREA OF PRECIP THAT IS NOW LOCATED OVER EASTERN NEBRASKA. TRIED TO TIME THIS BAND OF HEAVY SNOW IN THE HOURLY WEATHER GRIDS. IT SHOULD ARRIVE AT FAIRMONT BY 11/12Z...AND REACH THE METRO AREA AND ST CLOUD AROUND 15/16Z...AND IMPACT RICE LAKE/EAU CLAIRE AROUND 16/17Z. FURTHER WEST MODERATE TO HEAVY SNOW IS EXPECTED MOST OF THE DAY AS A TROWEL...SEEN IN THE H500-700 THICKNESS...DEVELOPS ACROSS CENTRAL MINNESOTA. AS THE CYCLONE CONTINUES TO OCCLUDE...THE MEDIUM RANGE AND HIRES MODELS ALL DEVELOP A SECOND AREA OF PRECIP AHEAD OF THE H500MB VORT MAX SUNDAY EVENING THAT LAGS THE SURFACE LOW AND TRACKS FROM ROUGHLY ALBERT LEA...THROUGH REDWING...AND LADYSMITH. THIS WILL DROP ADDITIONAL SNOW FALL ACROSS SOUTHERN MINNESOTA...WHICH COULD SET THE STAGE FOR BLIZZARD CONDITIONS EXTENDING AS FAR SOUTH AS I-90 SUNDAY NIGHT THROUGH MONDAY. BUFR FORECAST SOUNDINGS AT FAIRMONT FROM BOTH THE GFS AND NAM SHOW DIFFERENTIAL COLD AIR ADVECTION DESTABILIZING THE BOUNDARY LAYER SUNDAY NIGHT...WITH WINDS OF 40 TO 45KTS ATOP THE MIXED LAYER...AS WELL AS SATURATION AND WEAK LIFT WITHIN THE DEEP DENDRITIC ZONE. IF THE SNOWFALL FORECAST PANS OUT ACROSS SOUTHERN MINNESOTA TODAY AND THE DITCHES ARE FULL...THAN HAVE HIGH CONFIDENCE THAT THE BLIZZARD WARNING WILL NEED TO BE EXTENDED SOUTH LASTING THROUGH MONDAY AFTERNOON. GIVEN THE CURRENT COMPLEX HEADLINE SITUATION...HAVE OPTED TO JUST EXTEND THE WINTER WEATHER ADVISORY OUT IN TIME THROUGH MONDAY AFTERNOON SINCE THE BLIZZARD CONDITIONS WOULDNT DEVELOP UNTIL SUNDAY NIGHT. MONDAY NIGHT THROUGH FRIDAY...NORTHWEST FLOW WILL DEVELOP ACROSS THE REGION WITH A SURFACE HIGH BUILDING OVER THE UPPER MIDWEST IN THE WAKE OF THE STORM. LEE SIDE WARMING OVER THE CANADIAN PLAINS WILL KEEP THE COLDEST AIR ACROSS HUDSON BAY. A CLIPPER SYSTEM WILL MOVE ACROSS THE REGION MID WEEK AND BRING SOME LIGHT SNOW. POPS WILL LIKELY HAVE TO BE ADJUSTED UP FOR THIS SYSTEM IF IT REMAINS ON COURSE. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW BEHIND THIS CLIPPER...WITH SUB ZERO LOW TEMPERATURES POSSIBLE BY THE END OF THE WEEK. && .AVIATION... /06Z TAF ISSUANCE/ THE FIRST BAND OF LIGHT PRECIPITATION IS NEARING KAXN AND KRWF AT TAF ISSUANCE. MAINLY SNOW IS EXPECTED OVERNIGHT BUT SOME LIGHT FREEZING RAIN AND SLEET CAN NOT BE RULED OUT. THE TREND WILL BE FOR SEVERAL BANDS OF LIGHT PRECIPITATION TO MOVE THROUGH OVERNIGHT BEFORE A MORE PRONOUNCED AREA OF MODERATE TO HEAVY SNOW DEVELOPS IN THE MORNING AND LASTS THROUGH THE DAY. KSTC WILL ALSO SEE INTERMITTENT LIGHT SNOW OVERNIGHT ALONG WITH SOME BOUTS OF FREEZING DRIZZLE IN BETWEEN. BEST CHANCE FOR MODERATE TO HEAVY SNOW AT KSTC IS FROM LATE MORNING THROUGH THE EARLY AFTERNOON HOURS. KMSP...KRNH AND KEAU ARE MORE PROBLEMATIC ON PRECIPITATION TYPE AS SOME LOW LEVEL WARM AIR MAY RESULT IN A MIX OF LIGHT SNOW AND FREEZING RAIN DURING THE LATE NIGHT AND EARLY MORNING HOURS. CHANCES INCREASE FOR MODERATE TO HEAVY SNOW AT THESE SITES BETWEEN 15Z AND 21Z. AN ADDITIONAL THREAT FOR A PERIOD OF HEAVY SNOW EXISTS FOR KEAU SUNDAY EVENING ASSOCIATED WITH A MID LEVEL LOW MOVING THROUGH. THERE COULD ALSO BE SOME THUNDER AS WELL. NORTHWEST WINDS WILL BE ON THE INCREASE FOR KAXN AND KRWF IN THE EVENING WITH SUSTAINED SPEEDS OF 15 TO 20 KNOTS LIKELY ALONG WITH GUSTS FROM 25 TO 30 KNOTS. HIGHER WINDS AFTER 11/06Z WITH 25G35KTS COMMON ALONG WITH BLSN. KMSP...SOME LIGHT PRECIPITATION WILL REACH THE AIRFIELD AFTER 09Z. TRENDS CONTINUE TO POINT TO A MIX OF SNOW...SLEET AND FREEZING RAIN IN THE 10Z-14Z TIME FRAME WITH MODERATE TO HEAVY SNOW LIKELY FROM 15Z-19Z. SNOWFALL RATES DURING THE LATE MORNING AND EARLY AFTERNOON HOURS COULD BE AROUND 2 INCHES AN HOUR. LIGHTER SNOW EXPECTED DURING THE LATE AFTERNOON AND EVENING HOURS ALONG WITH THE WIND BACKING TO THE NORTHWEST LATE IN THE EVENING WITH SPEEDS OF 15 TO 20 KNOTS LIKELY ALONG WITH GUSTS OVERNIGHT FROM 25 TO 30 KNOTS. /OUTLOOK FOR KMSP/ MON...IFR EARLY WITH -SN/BLSN...THEN MVFR WITH -SN. NW WINDS 18G30KTS. TUE...VFR. W WINDS 5-10 KTS. WED...VFR. W WINDS 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR BLUE EARTH- FARIBAULT-FREEBORN-LE SUEUR-MARTIN-RICE-SCOTT-STEELE-WASECA- WATONWAN. WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR BROWN- CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-POPE- REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. BLIZZARD WARNING FROM 9 PM THIS EVENING TO 6 PM CST MONDAY FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET- POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR CARVER-MCLEOD- MEEKER-STEARNS-TODD-WRIGHT. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR ANOKA-BENTON- CHISAGO-HENNEPIN-ISANTI-KANABEC-MILLE LACS-MORRISON-RAMSEY- SHERBURNE-WASHINGTON. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR DAKOTA-GOODHUE. WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR CHIPPEWA-DUNN- EAU CLAIRE-PEPIN-PIERCE. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR BARRON-POLK-RUSK- ST. CROIX. && $$ JRB/BORGHOFF
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
334 AM EST TUE FEB 12 2013 .SYNOPSIS... A GUSTY WESTERLY FLOW WILL PREVAIL TODAY BEFORE A WEAK AREA OF HIGH PRESSURE ARRIVES TONIGHT. LOW PRESSURE MOVING THROUGH THE GULF COAST STATES EARLY WEDNESDAY WILL TRACK NORTHEAST TO A POSITION OFF THE DELMARVA PENINSULA BY LATE WEDNESDAY NIGHT. CONFIDENCE IS INCREASING ON A LIGHT TO MODERATE SNOW ACCUMULATION ACROSS SOUTH-CENTRAL PENNSYLVANIA WITH THE MID-WEEK SYSTEM. THE WEATHER PATTERN IS EXPECTED TO TURN COLDER INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SHRTWV TROUGH AXIS WILL ROTATE ACRS N-CENTRAL PA EARLY THIS MORNING. LOW-LEVEL CAA/STEEP LAPSE RATES AND WLY TRAJECTORY WILL SUPPORT OCNL UPSLOPE -SHSN OVER THE ALLEGHENY PLATEAU/NW MTNS EARLY TODAY. LITTLE TO NO ACCUM EXPECTED. RAP BUFKIT SOUNDINGS SHOW INVERSION HGTS LOWERING THRU THE MORNING...WITH INCREASING SUBSIDENCE IN WAKE OF SHRTWV/AREA OF HIGH PRES DRIFTING ENEWD FROM THE MID OH VLY. THIS SHOULD BRING AN END TO -SHSN ACTIVITY AROUND MID-DAY WITH JUST SOME SCT FLURRIES EXPECTED TO LINGER OVER THE NW MTNS INTO THE AFTN. THE LOW-LEVEL CAA/STEEP LAPSE RATES WILL MAINTAIN GUSTY WLY WINDS INTO THE AFTN. THE WIND ADVY LOOKS MARGINAL BASED ON MESONET DATA. TRIMMED COUNTIES NORTH OF I-80...BUT WILL CONTINUE THE ADVY FOR THE LAUREL HIGHLANDS/S-CENTRAL MTNS WHERE THE HIGHEST GUSTS ARE CURRENTLY BEING REPORTED. IN GENERAL...RAP SOUNDINGS SHOW PEAK GUSTS MAINLY IN THE 30-35KT RANGE WITH LOCALLY HIGHER GUSTS PSBL ON THE RIDGES. BKN-OVC STRATOCU WILL COVER THE N/W MTNS THRU THE AFTN WITH TEMPS IN THE LOW TO MID 30S. DOWNSLOPE FLOW E OF THE ALLEGHENY FRONT SHOULD HELP TO PROVIDE PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL RIDGE/VALLEY REGION AND SUSQ VLY...WITH TEMPS VARYING FROM THE UPPER 30S TO LOW 40S. WEAK HIGH PRES WILL DRIFT NEWD OVER THE AREA TONIGHT WITH M/CLR SKIES...LGT WINDS AND TEMPS MAINLY IN THE 20S. MID-HIGH LVL CLOUDS SHOULD BEGIN TO INCREASE FROM THE SOUTH BY DAYBREAK WED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WEAK SFC HIGH OVER EAST CENTRAL PA WILL RETREAT NEWD BY WEDNESDAY NIGHT AS A FAIRLY DISORGANIZED AREA OF LOW PRESSURE TRACKS OFF OF THE NC COAST AND OUT TO SEA WELL SOUTH OF LONG ISLAND AND CAPE COD. MAIN CHALLENGE FOR THE MEDIUM RANGE WILL BE TO ASCERTAIN THE IMPACTS OF THIS SYSTEM...AND PARTICULARLY THE NORTHERN EXTENT OF SIGNIFICANT SNOWFALL WEDNESDAY AFTERNOON AND NIGHT. 00Z DETERMINISTIC GUIDANCE COUPLED WITH 00Z GEFS EXAMINATION SHOWS A REASONABLE LIKELIHOOD OF ADVISORY CRITERIA SNOWFALL ACROSS THE SOUTHERN HALF OF CENTRAL PA. MARGINAL BOUNDARY LAYER TEMPERATURES AT THE ONSET OF PRECIPITATION WEDNESDAY AFTERNOON WILL CUT DOWN ON ACCUMS AND IF MEAN QPF WEREN`T A LIMITING FACTOR TO RULE OUT A WATCH AT THIS TIME...MARGINAL PBL TEMPERATURES WOULD BE...THUS NO WATCHS AT THIS TIME. AGAIN WENT WITH A BLEND OF OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND...PRODUCING A MAINLY LIGHT SNOWFALL WED AFTN AND NIGHT. NCEP WWD GRAPHICS DEPICT A 3-6 INCH STRIPE OVER MY SOUTHEAST COUNTIES WHICH I THINK IS SLIGHTLY OVERDONE GIVEN THE MELTING EXPECTED TO OCCUR AT THE ONSET. SNOW SHOULD BEGIN LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. 00Z GFS AND NAM12 IN REMARKABLE AGREEMENT ON PLACEMENT OF 0.25" QPF CONTOUR...FROM KJST TO KAOO EASTWARD TO KMDT. AREAS SOUTH WILL SEE UP TO .5" W.E. AND WILL AGAIN DEAL WITH MELTING FROM MARGINALLY COLD BOUNDARY LAYER/SFC TEMPS. THE MAGNITUDE OF THIS EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE. && .LONG TERM /THURSDAY THROUGH MONDAY/... AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... GUSTY NW FLOW PATTERN WILL BRING THE USUAL LOWER CIGS INTO THE WRN AIRFIELDS WITH SCT-BKN LOW VFR PREVAILING E OF THE ALLEGHENY FRONT. EXPECT SFC WIND GUSTS IN THE 25-40KT RANGE THROUGH THE DAY BEFORE SUBSIDING LATER THIS EVE AND INTO TONIGHT. A WEAK AREA OF HIGH PRES WILL PROVIDE VFR FLYING TONIGHT WITH MID-HIGH CLOUDS LKLY INCREASING AHEAD OF LOW PRESSURE DEVELOPING OVER THE GULF COAST STATES. THIS LOW IS EXPECTED TO TRACK ENE TO A POSITION OFF THE DELMARVA PENINSULA BY EARLY THURSDAY MORNING. OUTLOOK... WED...IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA. THU...MVFR/SHSN WEST. BCMG VFR CENTRAL/EAST. FRI-SAT...MVFR/SHSN WEST. VFR CENTRAL/EAST. GUSTY WNW WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ024-025-033- 034. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...DEVOIR/LA CORTE LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
301 AM EST TUE FEB 12 2013 .SYNOPSIS... A GUSTY WESTERLY FLOW WILL PREVAIL TODAY BEFORE A WEAK AREA OF HIGH PRESSURE ARRIVES TONIGHT. LOW PRESSURE MOVING THROUGH THE GULF COAST STATES EARLY WEDNESDAY WILL TRACK NORTHEAST TO A POSITION OFF THE DELMARVA PENINSULA BY LATE WEDNESDAY NIGHT. CONFIDENCE IS INCREASING ON A LIGHT TO MODERATE SNOW ACCUMULATION ACROSS SOUTH-CENTRAL PENNSYLVANIA WITH THE MID-WEEK SYSTEM. THE WEATHER PATTERN IS EXPECTED TO TURN COLDER INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SHRTWV TROUGH AXIS WILL ROTATE ACRS N-CENTRAL PA EARLY THIS MORNING. LOW-LEVEL CAA/STEEP LAPSE RATES AND WLY TRAJECTORY WILL SUPPORT OCNL UPSLOPE -SHSN OVER THE ALLEGHENY PLATEAU/NW MTNS EARLY TODAY. LITTLE TO NO ACCUM EXPECTED. RAP BUFKIT SOUNDINGS SHOW INVERSION HGTS LOWERING THRU THE MORNING...WITH INCREASING SUBSIDENCE IN WAKE OF SHRTWV/AREA OF HIGH PRES DRIFTING ENEWD FROM THE MID OH VLY. THIS SHOULD BRING AN END TO -SHSN ACTIVITY AROUND MID-DAY WITH JUST SOME SCT FLURRIES EXPECTED TO LINGER OVER THE NW MTNS INTO THE AFTN. THE LOW-LEVEL CAA/STEEP LAPSE RATES WILL MAINTAIN GUSTY WLY WINDS INTO THE AFTN. THE WIND ADVY LOOKS MARGINAL BASED ON MESONET DATA. TRIMMED COUNTIES NORTH OF I-80...BUT WILL CONTINUE THE ADVY FOR THE LAUREL HIGHLANDS/S-CENTRAL MTNS WHERE THE HIGHEST GUSTS ARE CURRENTLY BEING REPORTED. IN GENERAL...RAP SOUNDINGS SHOW PEAK GUSTS MAINLY IN THE 30-35KT RANGE WITH LOCALLY HIGHER GUSTS PSBL ON THE RIDGES. BKN-OVC STRATOCU WILL COVER THE N/W MTNS THRU THE AFTN WITH TEMPS IN THE LOW TO MID 30S. DOWNSLOPE FLOW E OF THE ALLEGHENY FRONT SHOULD HELP TO PROVIDE PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL RIDGE/VALLEY REGION AND SUSQ VLY...WITH TEMPS VARYING FROM THE UPPER 30S TO LOW 40S. WEAK HIGH PRES WILL DRIFT NEWD OVER THE AREA TONIGHT WITH M/CLR SKIES...LGT WINDS AND TEMPS MAINLY IN THE 20S. MID-HIGH LVL CLOUDS SHOULD BEGIN TO INCREASE FROM THE SOUTH BY DAYBREAK WED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... THE PRIMARY FEATURE OF CONCERN TO BEGIN THIS PERIOD WILL BE LINKED TO THE NOSE OF A QUITE POWERFUL UPPER JET /IN EXCESS OF 140 KTS/ LIFTING NE UP THE APPALACHIAN MTN CHAIN WEDNESDAY. THE INCREASINGLY DIFFLUENT UPPER PATTERN ACROSS THE MID ATLANTIC REGION LATER WED AND WED NIGHT...WILL COMBINE WITH A SLIGHTLY ANOMALOUS SERLY LLVL FLOW AND APPROX 1000 MB SFC LOW PRESSURE CONSOLIDATING/TRACKING RIGHT ACROSS THE DELMARVA REGION AROUND 06Z THURSDAY. SREF AND GEFS PLUMES /OVER THE PAST FEW DAYS/ HAVE GRADUALLY TRENDED TOWARD HIGHER QPF AMTS IN THE FORM OF MAINLY SNOW. EC...CANADIAN AND UKMET ALSO HAVE DISPLAYED A GRADUAL NWD SHIFT TO THE TRACK OF THEIR SFC LOW. USING A BLEND OF ALL THE OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND PRESENTS US WITH A FAIRLY GOOD CHANCE OF A LIGHT TO MODERATE SNOW EVENT BEGINNING LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. NUMEROUS SREF AND GEFS PLUMES INDICATE SIGNIFICANT QPF /AOA 0.50 OF AN INCH/ IN THE FORM OF SNOW. SREF/S MEAN 12 HOUR QPF IS AROUND 0.50 ACROSS THE EXTREME SE PART OF THE CWA...WITH THE 0.25 INCH LIQUID EQUIVALENT LINE EXTENDING ALONG MUCH OF INTERSTATE 80 IN CENTRAL PA...THEN ACROSS THE NRN POCONOS. THE 06Z NAM CONTINUES TO TREND TWD HIGHER QPF AS THE MOST AGGRESSIVE MODEL SOLUTION ATTM...AND COMPARABLE WITH SEVERAL OF THE 03Z SREF/ 00Z GEFS PLUMES. THE NAM/S 24-HOUR QPF /FROM ITS APPARENT MILLER B TYPE STORM/ IS AROUND 0.25 INCH ACROSS THE NRN TIER OF PENN...ABOUT 0.50 NEAR I-80...AND OVER 0.75 OF AN INCH ACROSS PORTIONS OF THE LOWER SUSQ REGION. THIS MAGNITUDE OF AN EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE...WITH POSSIBLY BORDERLINE WINTER STORM WARNING AMOUNTS ACROSS THE SRN HALF OF THE CWA. AT THIS POINT...CONSIDERING MUCH UNCERTAINTY WITH RESPECT TO THE EXACT SECONDARY LOW DEVELOPMENT NEAR THE VA COAST...AND INTERACTION OF THE NRN AND SRN STREAM WAVES...ITS PRUDENT TO RAMP UP THE SNOW PROBABILITIES AND AMOUNTS GRADUALLY...AND HEIGHTEN AWARENESS IN OUR HAZARDOUS WEATHER OUTLOOK /PHLHWOCTP/. && .LONG TERM /THURSDAY THROUGH MONDAY/... 1016-1018 MB SFC HIGH PRESSURE BUILD NEWD ACROSS THE STATE TUESDAY NIGHT WITH FAIR SKIES...LIGHT WIND...AND CHILLY TEMPS MAINLY IN THE 20S. A FAIRLY AMPLIFIED...SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... GUSTY NW FLOW PATTERN WILL BRING THE USUAL LOWER CIGS INTO THE WRN AIRFIELDS WITH SCT-BKN LOW VFR PREVAILING E OF THE ALLEGHENY FRONT. EXPECT SFC WIND GUSTS IN THE 25-40KT RANGE THROUGH THE DAY BEFORE SUBSIDING LATER THIS EVE AND INTO TONIGHT. A WEAK AREA OF HIGH PRES WILL PROVIDE VFR FLYING TONIGHT WITH MID-HIGH CLOUDS LKLY INCREASING AHEAD OF LOW PRESSURE DEVELOPING OVER THE GULF COAST STATES. THIS LOW IS EXPECTED TO TRACK ENE TO A POSITION OFF THE DELMARVA PENINSULA BY EARLY THURSDAY MORNING. OUTLOOK... WED...IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA. THU...MVFR/SHSN WEST. BCMG VFR CENTRAL/EAST. FRI-SAT...MVFR/SHSN WEST. VFR CENTRAL/EAST. GUSTY WNW WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ004>006- 010>012-017-018-024-025-033-034. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...FITZGERALD/LA CORTE/LAMBERT LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1151 PM CST MON FEB 11 2013 .DISCUSSION... SEE AVIATION SECTION. && .AVIATION... ELEVATED CONVECTION IS DEVELOPING/INCREASING IN COVERAGE ACROSS WEST CENTRAL TEXAS. LATEST RADAR TRENDS AND SHORT-RANGE MODEL DATA INDICATE THAT THE GREATEST COVERAGE WILL BE ACROSS THE BIG COUNTRY AND NORTHERN CONCHO VALLEY DURING THE OVERNIGHT HOURS. CARRYING A TSRA GROUP AT KABI...WITH A VCSH MENTION AT KSJT AND KBBD. BRIEF HEAVY RAIN IS POSSIBLE...AND A FEW OF THE STRONGEST STORMS MAY CONTAIN SMALL HAIL. WITH ONGOING LOW-LEVEL MOIST ADVECTION...CLOUD CEILINGS WILL CONTINUE TO DECREASE OVERNIGHT. HAVE TRENDED CLOSER TO MODEL GUIDANCE WITH THE 06Z TAF PACKAGE. IFR CEILINGS ARE EXPECTED OVERNIGHT AT ALL SITES EXCEPT KSJT... WHERE CEILING SHOULD STAY ABOVE 1K FT. WINDS WILL BE EAST- SOUTHEAST AT 9-12 KT THROUGH EARLY TUESDAY MORNING. A DRY AIR SURGE FROM THE WEST WILL OVERSPREAD WEST CENTRAL TEXAS TUESDAY MORNING. WITH THE ONSET OF WEST WINDS...SKIES WILL CLEAR OUT QUICKLY WITH VFR CONDITIONS EXPECTED THROUGH THE REST OF THE DAY. GUSTY WEST WINDS WILL OCCUR DURING THE LATE MORNING AND AFTERNOON HOURS AT ALL TAF SITES EXCEPT KABI...WHERE A COLD FRONT WILL ARRIVE BY 21Z. THE COLD FRONT WILL PUSH SOUTH ACROSS WEST CENTRAL TEXAS DURING THE AFTERNOON AND EVENING HOURS. GUSTY WEST WINDS WILL SHIFT TO NORTH- NORTHWEST WITH PASSAGE OF THIS FRONT. WIND SPEEDS WILL DECREASE DURING THE FINAL HOURS OF THE TAF PERIOD. && .PREV DISCUSSION... /ISSUED 1106 PM CST MON FEB 11 2013/ UPDATE... NEW MODEL DATA HAS ARRIVED...AND NUMEROUS THUNDERSTORMS ACROSS THE BIG COUNTY FOR THE REMAINDER OF TONIGHT DOES NOT LOOK AS PROMISING. THE LATEST MESOSCALE DATA FROM THE STORM PREDICTION CENTER DO INDICATE MID-LEVEL CAPES HAVE INCREASE ACROSS AT LEAST SOME OF OUR WESTERN COUNTIES DURING THE LAST COUPLE HOURS. THUS...I STILL EXPECT THUNDERSTORM TONIGHT. THE LATEST RUC AND NAM MODEL DATA CONTINUE TO INDICATE THE BEST POTENTIAL FOR SHOWERS AND THUNDERSTORMS WILL BE ACROSS MAINLY OUR BIG COUNTRY COUNTIES TONIGHT. SO...I DID MAINTAIN THE HIGHEST POPS THERE FOR THE REMAINDER OF TONIGHT. HOWEVER...I DID REDUCE THUNDERSTORM COVERAGE FROM NUMEROUS TO SCATTERED. ELSEWHERE TONIGHT...ISOLATED THUNDERSTORMS LOOK REASONABLE. ALSO...THE LATEST SATELLITE DATA INDICATE LOW CLOUDS AND HIGHER CLOUDS ARE COMBINING TO PRODUCE CLOUDY SKIES ACROSS ALL OF WEST CENTRAL TEXAS AT THIS TIME. SO...I ALSO ADJUSTED SKY CONDITIONS TO REFLECT CLOUDY SKIES FOR THE REMAINDER OF TONIGHT. ALL ELSE FOR THE REMAINDER OF TONIGHT LOOKS GOOD. RECENT ZONE AND OTHER PRODUCTS REFLECT THESE CHANGES. HUBER PREV DISCUSSION... /ISSUED 603 PM CST MON FEB 11 2013/ DISCUSSION... SEE AVIATION SECTION. AVIATION... A DEGRADATION OF CONDITIONS IS EXPECTED TONIGHT ACROSS WEST CENTRAL TEXAS...AS LOW-LEVEL MOISTURE INCREASES SUBSTANTIALLY AND CLOUD CEILINGS DECREASE. WITH SOME UNCERTAINTY ON HOW LOW THE CEILINGS AND VISIBILITIES WILL BE...TAKING A CONSERVATIVE APPROACH AT THIS TIME. CURRENTLY THIS EVENING...CLOUD CEILINGS ARE ABOVE 3K FT AT ALL TAF SITES EXCEPT KJCT. EXPECT CEILINGS TO LOWER INTO THE MVFR CATEGORY BY 06Z AT KABI AND KSJT...AND BETWEEN 00Z AND 06Z AT KBBD AND KSOA. ELEVATED CONVECTION IS EXPECTED TO DEVELOP BETWEEN 03Z AND 06Z...AND THEN TO CONTINUE OVERNIGHT. THE GREATER COVERAGE WILL LIKELY BE OVER THE BIG COUNTRY. CARRYING A -TSRA MENTION AT KABI...AND HAVE INSERTED VCSH AT KSJT. GOING WITH IFR CONDITIONS LATE TONIGHT AT KABI...WITH LOW END MVFR CONDITIONS AT KBBD AND KJCT. CARRYING CEILINS IN THE 1500-2000 FT RANGE AT KSOA AND KSJT. A DRY PUNCH FROM THE WEST WILL OVERSPREAD WEST CENTRAL TEXAS ON TUESDAY MORNING. WITH THE ONSET OF WEST WINDS...SKIES WILL CLEAR QUICKLY WITH VFR CONDITIONS EXPECTED THROUGH THE REST OF THE DAY. GUSTY WEST WINDS ARE EXPECTED DURING THE LATE MORNING AND AFTERNOON HOURS. A COLD FRONT WILL PUSH SOUTH ACROSS ROUGHLY THE NORTHERN HALF OF WEST CENTRAL TEXAS DURING THE AFTERNOON...REACHING KABI AROUND 21Z. WINDS WILL SHIFT TO THE NORTH WITH PASSAGE OF THIS FRONT. PREV DISCUSSION... /ISSUED 342 PM CST MON FEB 11 2013/ SHORT TERM... STILL SHOWING SOME LIGHT SHOWERS OVER OUR SOUTHEASTERN COUNTIES EARLY THIS AFTERNOON ASSOCIATED WITH ON-GOING WEAK ISENTROPIC ASCENT OVER A FRONTAL BOUNDARY LOCATED SOUTH OF THE FORECAST AREA. THIS ACTIVITY SHOULD CONTINUE TO WEAKEN THROUGH THE REMAINDER OF THE AFTERNOON...WILL HOWEVER KEEP SHOWERS AND ISOLATED THUNDERSTORMS OVER OUR SOUTHEASTERN COUNTIES PRE FIRST PERIOD. AN UPPER LEVEL LOW OVER THE FOUR CORNERS AREA THIS EVENING WILL MOVE EAST OVER THE RED RIVER VALLEY BY LATE TOMORROW AFTERNOON... PUSHING A PACIFIC FRONT/DRYLINE THROUGH THE FORECAST AREA TUESDAY MORNING. IN ADVANCE OF THIS UPPER LEVEL SYSTEM... MOISTURE ADVECTING NORTH OVER THE FORECAST AREA TONIGHT WILL SATURATE THE SURFACE TO 850MB LAYER OVER MOST OF THE CWA AS A LLJ STRENGTHENS OVER THE NORTHERN FORECAST AREA AFTER MIDNIGHT. LATEST FORECAST SOUNDINGS ARE SHOWING THE BEST CHANCE OF CONVECTION OVER THE NORTHERN CWA AFTER MIDNIGHT AS UPPER LEVEL SHEAR AND INSTABILITY INCREASES. THE LATEST 3KM WRF MODEL IS ALSO HIGHLIGHTING THE BIG COUNTRY AS HAVING THE BEST OPPORTUNITY FOR RAINFALL. WILL THEREFORE LEAVE THE HIGHER POPS OVER THE NORTHERN CWA THROUGH THE NIGHT WITH RAINFALL ENDING FROM THE SOUTHWEST TO THE NORTHEAST FROM DAYBREAK TO AROUND NOON. WITH CLOUDY SKIES OVERNIGHT...WILL SEE TUESDAY MORNING LOWS GENERALLY IN THE MID 40S...WARMING INTO THE 50S OVER THE BIG COUNTRY AND INTO THE 60S OVER THE REMAINDER OF THE FORECAST AREA. SKIES WILL BE CLEARING FROM THE WEST THROUGH THE DAY ON TUESDAY. LONG TERM... VERY FEW CHANGES TO THE EXTENDED FORECAST FOR THE REST OF THE WEEK AND INTO THE WEEKEND. WITH THE PASSAGE OF THE UPPER LEVEL STORM SYSTEM TOMORROW...DRY NORTHWEST FLOW ALOFT PREVAILS INTO THE WEEKEND. WILL CONTINUE TO MONITOR THE PATH OF THE NEXT UPPER LEVEL TROUGH FOR FRODAY AND SATURDAY...BUT BOTH THE GFS AND THE ECMWF HAVE CONTINUED THE TREND OF A WEAKER PROGRESSIVE SHORTWAVE PASSING ACROSS THE AREA...INSTEAD OF THE CLOSED OFF SYSTEM THEY WERE SHOWING SEVERAL DAYS AGO. WITH THIS WEAKER MORE PROGRESSIVE SYSTEM...WILL KEEP THE FORECAST DRY FOR NOW. MODELS HAVE SOME DIFFERENCES WITH THE TIMING OF A COLD FRONT ON FRIDAY. WILL STICK TO THE ECMWF FOR NOW...SHOWING A LITTLE FASTER FRONT AND A LITTLE COOLER TEMPERATURES FOR FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 44 56 33 59 35 / 70 30 5 0 0 SAN ANGELO 45 62 35 62 32 / 40 20 0 0 0 JUNCTION 47 64 33 63 30 / 40 20 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1132 PM CST MON FEB 11 2013 .AVIATION... FOR THE 06Z TAFS...A VERY FAST EVOLVING SYSTEM HAS LED TO SOME CHANGES FROM THE 00Z TAF ISSUANCE. THE BIGGEST CHANGE IS THE FASTER ONSET OF SN. ALREADY SN IS REPORTED IN WESTERN PANHANDLES AND SHOULD BEGIN IN KDHT AND KAMA WITHIN THE NEXT HOUR...AND KGUY WITHIN THE NEXT 2 HOURS. EXPECT INTERMITTENT SHSN THROUGH 09Z...BEFORE IT TRANSITIONS TO A MORE WIDESPREAD EVENT. ANOTHER CHANGE IS THE OBSERVATION OF TSSN IN THE SOUTHERN TX PANHANDLE...INCLUDING N OF KAMA. AT THIS POINT WILL NOT INCLUDE ANY TSSN IN THE TAFS AS THE INITIAL THREAT IS N OF KAMA AND VERY UNLIKELY TO GET AS FAR N AS KDHT. THE RAP INDICATES SOME INSTABILITY BETWEEN 09 AND 12Z...AND THUS SOME THREAT AGAIN FOR TSSN BUT THE LIKELIHOOD OF IT REDEVELOPING IS LOW...AND WOULD BE ISOLATED AT BEST...SO WILL NOT INCLUDE IN THE TAFS. STILL THINK THE HEAVIEST SN...AND THUS LOWEST VISIBILITIES WILL BE AT KAMA...WHERE 1/2SM IS LIKELY...AND BRIEF PERIODS OF 1/4SM ARE POSSIBLE. OUTSIDE OF THE HEAVIEST BANDS OF SN...EXPECT VISIBILITIES MAINLY BETWEEN 1 AND 3SM FOR THE MAJORITY OF THIS EVENT. THIS IS MORE PESSIMISTIC THAN THE GFS LAMP...BUT GIVEN UPSTREAM OBS...THINK THE LOWER VISIBILITIES ARE LIKELY. MODELS ARE ALSO TRENDING FASTER NOW WITH THE SN LEAVING THE AREA...THINK THAT THE MAJORITY OF THE SN WILL BE BEFORE 18Z. ONCE THE SN LEAVES...MAY BE A PERIOD OF MVFR CEILINGS...BEFORE CONDITIONS RETURN TO VFR. JOHNSON && .PREV DISCUSSION... /ISSUED 954 PM CST MON FEB 11 2013/ UPDATE... HAVE MADE A FEW CHANGES TO GOING FORECAST AS RECENT MODEL TRENDS HAVE TRENDED EARLIER...COLDER...AND A BIT HEAVIER WITH THE IMPENDING SNOW. SNOW HAS ALREADY SPREAD INTO THE WESTERN TEXAS PANHANDLE...WITH TEXLINE REPORTING MODERATE SNOW. TIMING... HAVE SHIFTED ALMOST ALL AREAS FORWARD ABOUT 3 HOURS FOR THE ONSET OF SNOW GIVEN RECENT HRRR AND NAM RUNS. THIS BRINGS TOTALS UP TO 1-3 INCHES SW OF A CANADIAN TO GUYMON LINE BEFORE THE MORNING COMMUTE. THE I40 CORRIDOR EAST OF AMARILLO WILL LIKELY SEE THE HEAVIEST SNOWS BEFORE 12Z AND THROUGHOUT THE EVENT. HAVE ALSO BROUGHT THE SNOW TO AN END QUICKER...WITH ALL SNOWS LIKELY EAST OF THE PANHANDLES BY 00Z. AMOUNTS... THE MAIN CHANGE WAS TO INCREASE AMOUNTS IN AN AREA BOUNDED BY ROUGHLY I27 ON THE WEST AND I40 ON THE NORTH. IT PREVIOUSLY APPEARED THAT THE DAYTIME TIMING AND SUBSEQUENT LOWER SNOW TO LIQUID RATIOS WOULD KEEP TOTALS DOWN A BIT IN THESE AREAS. HOWEVER...THE BULK OF THE SNOW NOW LOOKS TO FALL BETWEEN 09Z-15Z...MEANING THAT RATIOS WILL LIKELY BE HIGHER AND AMOUNTS GREATER. GIVEN SOME LIKELY MODEL UNDERESTIMATION OF DYNAMIC COOLING IN THESE AREAS...FELT A BUMP UP IN TOTALS PRUDENT. CURRENT THINKING IS THAT THE AMARILLO AREA COULD SEE 4-7 INCHES...WITH HIGHER AMOUNTS FURTHER EAST. GIVEN RECENT MODEL TRENDS...AM A BIT CONCERNED WE COULD END UP SEEING AN ISOLATED BIG NUMBER IN THE DOUBLE DIGITS SOMEWHERE IN THE ROBERTS/GRAY/ HEMPHILL/WHEELER COUNTY AREA. UPDATED GRIDS/ZONES WILL BE OUT VERY SOON. SIMPSON PREV DISCUSSION... /ISSUED 543 PM CST MON FEB 11 2013/ AVIATION... FOR THE 00Z KAMA TAF...VFR CONDITIONS ARE EXPECTED THROUGH 06Z...THEN A WINTER STORM LEADS TO A MORE COMPLICATED AND LOWER CONFIDENCE FORECAST AFTER 06Z THROUGH THE END OF THE TAF PERIOD. HIGH CONFIDENCE THAT THE TERMINAL WILL SEE SN...PRIMARILY BETWEEN 09 AND 18Z...AND IFR OR LOWER CONDITIONS THROUGH THIS TIME. THOUGH WINDS WILL BE BREEZY BETWEEN 12 AND 18Z...DO NOT EXPECT TOO MUCH BLSN DUE TO THE SNOW TO LIQUID RATIO BEING A BIT LOW. SN WILL SLOWLY TAPER OFF AFTER 18Z...AND SHOULD BE OUT OF THE AREA BY 21Z. CONDITIONS SHOULD IMPROVE TO VFR ONCE THE SN ENDS. FOR THE 00Z KDHT AND KGUY TAFS...VFR CONDITIONS ARE LIKELY THROUGH 06Z...WITH THE ONLY POSSIBLE EXCEPTION OF LIGHT SN STARTING IN KDHT POSSIBLY AS EARLY AS 03Z. AFTER 06Z...THERE IS LOWER CONFIDENCE GIVEN THE INCOMING WINTER STORM. AT THIS POINT...EXPECT SN TO START IN KDHT LIKELY AROUND 06Z...AND KGUY BETWEEN 09 AND 12Z. FOR THE MOST PART THROUGH THIS EVENT...EXPECT LOW MVFR OR IFR CONDITIONS. SN AT THESE 2 TERMINALS IS NOT EXPECTED TO BE AS DEEP OR HEAVY AS KAMA. SN SHOULD BEGIN TO TAPER OFF NEAR 18Z...AND SHOULD BE OUT OF THE AREA BY 21Z. ONCE THE SN ENDS...EXPECT VFR CONDITIONS THROUGH THE REMAINDER OF THE TAF PERIOD. JOHNSON PREV DISCUSSION... /ISSUED 400 PM CST MON FEB 11 2013/ DISCUSSION... THROUGH TONIGHT: UPPER TROUGH MOVING ACROSS THE FOUR CORNERS WILL DEEPEN AS IT APPROACHES THE PANHANDLES TONIGHT. AHEAD OF THIS UPPER TROUGH, EASTERLY UPSLOPE WINDS AND ISENTROPIC LIFT WILL INCREASE MOISTURE SUBSTANTIALLY AS THE NIGHT PROGRESSES. THE COMBINATION OF THE LOW- AND UPPER-LEVEL LIFT AND MOISTURE SHOULD TRIGGER THE DEVELOPMENT OF PRECIPITATION ACROSS NORTHEAST NEW MEXICO LATER THIS EVENING AND THEN SPREAD INTO THE NORTHWEST PANHANDLES AFTER 9 PM. AS TEMPERATURES COOL, THIS PRECIPITATION IS EXPECTED TO FALL AS SNOW, ROUGHLY WEST OF A GUYMON TO BOOTLEG LINE THROUGH MIDNIGHT. SOME LIGHT ACCUMULATIONS OF AROUND ONE HALF OF AN INCH WILL BE POSSIBLE ACROSS THE WESTERN PORTIONS OF CIMARRON AND DALLAM COUNTIES. AFTER MIDNIGHT, CHANCES FOR PRECIPITATION WILL INCREASE AND CONTINUE ACROSS THE NORTHWEST. A SECOND, MORE CONCENTRATED, SWATCH OF PRECIPITATION IS EXPECTED TO SPREAD NORTHWARD INTO THE SOUTHEASTERN TEXAS PANHANDLE AFTER 3 AM. FORECAST SOUNDINGS AFTER 3 AM WILL BE SUPPORTIVE OF WET SNOW ACROSS MOST OF THESE AREAS. HOWEVER, FOR LOCATIONS SOUTH AND EAST OF A LINE FROM CLARENDON TO SHAMROCK, WET BULB ZERO HEIGHTS WILL REMAIN ABOVE 2,000 FEET...WHICH WILL KEEP THE PRECIPITATION TYPE AS RAIN. AS THE COLUMN COOLS TOWARDS SUNRISE, THE RAIN IS EXPECTED TO TRANSITION TO SNOW IN THESE LOCATIONS. IN BETWEEN THESE TWO AREAS, INCLUDING AMARILLO, BORGER, AND PERRYTON, THERE MAY NOT BE MUCH IN THE WAY OF PRECIPITATION OVERNIGHT. HOWEVER, WE KEPT A MENTION OF SNOW IN THE FORECAST, BUT AMOUNTS IN THESE LOCATIONS WILL BE A DUSTING TO ONE HALF OF AN INCH AT MOST. TUESDAY-TUESDAY NIGHT: THE BEST COMBINATION OF DYNAMICS AND MOISTURE WILL OCCUR DURING THE DAY ON TUESDAY. AS THIS OCCURS, SNOW IS EXPECTED TO DEVELOP ACROSS ALL OF THE PANHANDLES WITH THE HIGHEST CHANCES BEING SOUTHEAST OF A GUYMON TO HEREFORD LINE. DUE TO STRONG DYNAMICS IN PLACE, SOME OF THE SNOW COULD BE HEAVY AT TIMES. THE TIME FRAME FOR THE HEAVIEST SNOW LOOKS TO BE BETWEEN 8 AM AND 3 PM. MOISTURE WILL BE LOWEST ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE PANHANDLES. AS A RESULT, THESE LOCATIONS WILL LIKELY SEE THE LIGHTEST SNOWFALL ACCUMULATIONS, BUT TOTAL SNOWFALL AMOUNTS WILL STILL BE BETWEEN 2 AND 5 INCHES WITH LOCALLY HIGHER AMOUNTS UP TO 6 INCHES. DEEPER MOISTURE WILL BE CONFINED TO THE SOUTHEAST THIRD OF THE PANHANDLES WHERE TOTAL SNOWFALL ACCUMULATIONS WILL BE BETWEEN 6 AND 9 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THE HEAVIEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR IN AN AREA EAST OF A LINE FROM CANADIAN TO PAMPA TO CLAUDE AND GENERALLY NORTH OF INTERSTATE 40. IT`S NOT OUT OF THE QUESTION SOME LOCATION IN THIS AREA COULD RECEIVE AS MUCH AS 10 INCHES OF SNOW. WE DO HAVE SOME CONCERN THAT MODELS HAVE BEGUN TRENDING SLIGHTLY FARTHER NORTH WITH THE UPPER TROUGH. THIS COULD SIGNIFICANTLY REDUCE THE SNOW AMOUNTS IN THE SOUTHERN PART OF THE TEXAS PANHANDLE AND SHIFT THE HIGHER TOTALS FARTHER NORTH. WE`LL NEED TO WATCH THIS CLOSELY IN CASE THE WINTER STORM WARNING NEEDS TO BE ADJUSTED. WE HAVE HIGH CONFIDENCE THAT EVERY LOCATION WILL SEE AT LEAST SOME SNOW OVER THE NEXT 24 HOURS, AND THIS IS SUPPORTED BY THE CIPS ANALOG GUIDANCE. THE SNOW IS EXPECTED TO BEGIN TAPERING OFF FROM NORTHWEST TO SOUTHEAST BY LATE TUESDAY AFTERNOON. THERE IS A POSSIBILITY THAT TEMPERATURES WILL RISE ABOVE FREEZING DURING THE AFTERNOON ACROSS MOST OF THE AREA, ESPECIALLY ACROSS THE NORTHWEST HALF OF THE PANHANDLES AND THE FAR SOUTHEASTERN TEXAS PANHANDLE. THIS WILL LIKELY HELP LIMIT/SIGNIFICANTLY CUT DOWN ON ADDITIONAL SNOWFALL ACCUMULATIONS. TUESDAY EVENING, SNOW IS EXPECTED TO CONTINUE EAST OF A BEAVER TO CLAUDE LINE THROUGH TUESDAY EVENING BEFORE ENDING BY MIDNIGHT. LOW TEMPERATURES IN THE TEENS TO LOWER 20S WILL BE LIKELY DUE TO LIGHT WINDS, CLEAR SKIES, AND SNOW COVER. JACKSON WEDNESDAY-MONDAY: AN UPPER TROUGH WILL MOVE EAST OF THE PANHANDLES WEDNESDAY WITH A DRY NORTHWESTERLY UPPER FLOW ACROSS THE PANHANDLES WEDNESDAY AND THURSDAY. A NORTHERN STREAM SHORTWAVE TROUGH WILL DROP SOUTHEAST OUT OF THE ROCKIES BY LATE THURSDAY AND ALLOW FOR A STRONG COLD FRONT TO PUSH THROUGH THE FORECAST AREA WEDNESDAY NIGHT AND THURSDAY MORNING. SCATTERED RAIN OR SNOW SHOWERS ARE EXPECTED TO PUSH SOUTH AND EAST ACROSS THE NORTHERN SECTIONS OF THE PANHANDLES THURSDAY NIGHT...AND THEN ACROSS MUCH OF THE PANHANDLES FRIDAY. SNOW COVER WEDNESDAY AND POSSIBLY EVEN INTO THURSDAY WILL HOLD TEMPERATURES DOWN...SO UNDERCUT MOS GUIDANCE. COLDER FRIDAY AND TEMPERATURES SATURDAY WILL DEPEND ON ANY SNOW COVER FROM THE THURSDAY NIGHT AND FRIDAY SYSTEM. OTHERWISE...MODERATING CONDITIONS LATE THIS WEEK AND INTO THE WEEKEND AS HIGH PRESSURE PREVAILS WITH A DRY NORTHWESTERLY FLOW ALOFT. SCHNEIDER FIRE WEATHER... AN UPPER TROUGH WILL APPROACH THE TEXAS AND OKLAHOMA PANHANDLES TONIGHT AND TUESDAY BRINGING INCREASING CHANCES FOR SNOW. ALTHOUGH THE SNOW IS EXPECTED TO END BY TUESDAY EVENING AS THE UPPER TROUGH MOVES OFF TO THE EAST OF THE PANHANDLES...THE SNOW COVER WILL LINGER THROUGH WEDNESDAY. THEREFORE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH WEDNESDAY. SCHNEIDER && .AMA WATCHES/WARNINGS/ADVISORIES... TX...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH...HANSFORD...HARTLEY...MOORE... OCHILTREE...OLDHAM...SHERMAN. WINTER STORM WARNING FROM 3 AM TO 6 PM CST TUESDAY FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH... DONLEY...GRAY...HEMPHILL...HUTCHINSON...LIPSCOMB...POTTER... RANDALL...ROBERTS...WHEELER. OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS. && $$ 16/09
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1106 PM CST MON FEB 11 2013 .UPDATE... NEW MODEL DATA HAS ARRIVED...AND NUMEROUS THUNDERSTORMS ACROSS THE BIG COUNTY FOR THE REMAINDER OF TONIGHT DOES NOT LOOK AS PROMISING. THE LATEST MESOSCALE DATA FROM THE STORM PREDICTION CENTER DO INDICATE MID-LEVEL CAPES HAVE INCREASE ACROSS AT LEAST SOME OF OUR WESTERN COUNTIES DURING THE LAST COUPLE HOURS. THUS...I STILL EXPECT THUNDERSTORM TONIGHT. THE LATEST RUC AND NAM MODEL DATA CONTINUE TO INDICATE THE BEST POTENTIAL FOR SHOWERS AND THUNDERSTORMS WILL BE ACROSS MAINLY OUR BIG COUNTRY COUNTIES TONIGHT. SO...I DID MAINTAIN THE HIGHEST POPS THERE FOR THE REMAINDER OF TONIGHT. HOWEVER...I DID REDUCE THUNDERSTORM COVERAGE FROM NUMEROUS TO SCATTERED. ELSEWHERE TONIGHT...ISOLATED THUNDERSTORMS LOOK REASONABLE. ALSO...THE LATEST SATELLITE DATA INDICATE LOW CLOUDS AND HIGHER CLOUDS ARE COMBINING TO PRODUCE CLOUDY SKIES ACROSS ALL OF WEST CENTRAL TEXAS AT THIS TIME. SO...I ALSO ADJUSTED SKY CONDITIONS TO REFLECT CLOUDY SKIES FOR THE REMAINDER OF TONIGHT. ALL ELSE FOR THE REMAINDER OF TONIGHT LOOKS GOOD. RECENT ZONE AND OTHER PRODUCTS REFLECT THESE CHANGES. HUBER && .PREV DISCUSSION... /ISSUED 603 PM CST MON FEB 11 2013/ DISCUSSION... SEE AVIATION SECTION. AVIATION... A DEGRADATION OF CONDITIONS IS EXPECTED TONIGHT ACROSS WEST CENTRAL TEXAS...AS LOW-LEVEL MOISTURE INCREASES SUBSTANTIALLY AND CLOUD CEILINGS DECREASE. WITH SOME UNCERTAINTY ON HOW LOW THE CEILINGS AND VISIBILITIES WILL BE...TAKING A CONSERVATIVE APPROACH AT THIS TIME. CURRENTLY THIS EVENING...CLOUD CEILINGS ARE ABOVE 3K FT AT ALL TAF SITES EXCEPT KJCT. EXPECT CEILINGS TO LOWER INTO THE MVFR CATEGORY BY 06Z AT KABI AND KSJT...AND BETWEEN 00Z AND 06Z AT KBBD AND KSOA. ELEVATED CONVECTION IS EXPECTED TO DEVELOP BETWEEN 03Z AND 06Z...AND THEN TO CONTINUE OVERNIGHT. THE GREATER COVERAGE WILL LIKELY BE OVER THE BIG COUNTRY. CARRYING A -TSRA MENTION AT KABI...AND HAVE INSERTED VCSH AT KSJT. GOING WITH IFR CONDITIONS LATE TONIGHT AT KABI...WITH LOW END MVFR CONDITIONS AT KBBD AND KJCT. CARRYING CEILINS IN THE 1500-2000 FT RANGE AT KSOA AND KSJT. A DRY PUNCH FROM THE WEST WILL OVERSPREAD WEST CENTRAL TEXAS ON TUESDAY MORNING. WITH THE ONSET OF WEST WINDS...SKIES WILL CLEAR QUICKLY WITH VFR CONDITIONS EXPECTED THROUGH THE REST OF THE DAY. GUSTY WEST WINDS ARE EXPECTED DURING THE LATE MORNING AND AFTERNOON HOURS. A COLD FRONT WILL PUSH SOUTH ACROSS ROUGHLY THE NORTHERN HALF OF WEST CENTRAL TEXAS DURING THE AFTERNOON...REACHING KABI AROUND 21Z. WINDS WILL SHIFT TO THE NORTH WITH PASSAGE OF THIS FRONT. PREV DISCUSSION... /ISSUED 342 PM CST MON FEB 11 2013/ SHORT TERM... STILL SHOWING SOME LIGHT SHOWERS OVER OUR SOUTHEASTERN COUNTIES EARLY THIS AFTERNOON ASSOCIATED WITH ON-GOING WEAK ISENTROPIC ASCENT OVER A FRONTAL BOUNDARY LOCATED SOUTH OF THE FORECAST AREA. THIS ACTIVITY SHOULD CONTINUE TO WEAKEN THROUGH THE REMAINDER OF THE AFTERNOON...WILL HOWEVER KEEP SHOWERS AND ISOLATED THUNDERSTORMS OVER OUR SOUTHEASTERN COUNTIES PRE FIRST PERIOD. AN UPPER LEVEL LOW OVER THE FOUR CORNERS AREA THIS EVENING WILL MOVE EAST OVER THE RED RIVER VALLEY BY LATE TOMORROW AFTERNOON... PUSHING A PACIFIC FRONT/DRYLINE THROUGH THE FORECAST AREA TUESDAY MORNING. IN ADVANCE OF THIS UPPER LEVEL SYSTEM... MOISTURE ADVECTING NORTH OVER THE FORECAST AREA TONIGHT WILL SATURATE THE SURFACE TO 850MB LAYER OVER MOST OF THE CWA AS A LLJ STRENGTHENS OVER THE NORTHERN FORECAST AREA AFTER MIDNIGHT. LATEST FORECAST SOUNDINGS ARE SHOWING THE BEST CHANCE OF CONVECTION OVER THE NORTHERN CWA AFTER MIDNIGHT AS UPPER LEVEL SHEAR AND INSTABILITY INCREASES. THE LATEST 3KM WRF MODEL IS ALSO HIGHLIGHTING THE BIG COUNTRY AS HAVING THE BEST OPPORTUNITY FOR RAINFALL. WILL THEREFORE LEAVE THE HIGHER POPS OVER THE NORTHERN CWA THROUGH THE NIGHT WITH RAINFALL ENDING FROM THE SOUTHWEST TO THE NORTHEAST FROM DAYBREAK TO AROUND NOON. WITH CLOUDY SKIES OVERNIGHT...WILL SEE TUESDAY MORNING LOWS GENERALLY IN THE MID 40S...WARMING INTO THE 50S OVER THE BIG COUNTRY AND INTO THE 60S OVER THE REMAINDER OF THE FORECAST AREA. SKIES WILL BE CLEARING FROM THE WEST THROUGH THE DAY ON TUESDAY. LONG TERM... VERY FEW CHANGES TO THE EXTENDED FORECAST FOR THE REST OF THE WEEK AND INTO THE WEEKEND. WITH THE PASSAGE OF THE UPPER LEVEL STORM SYSTEM TOMORROW...DRY NORTHWEST FLOW ALOFT PREVAILS INTO THE WEEKEND. WILL CONTINUE TO MONITOR THE PATH OF THE NEXT UPPER LEVEL TROUGH FOR FRODAY AND SATURDAY...BUT BOTH THE GFS AND THE ECMWF HAVE CONTINUED THE TREND OF A WEAKER PROGRESSIVE SHORTWAVE PASSING ACROSS THE AREA...INSTEAD OF THE CLOSED OFF SYSTEM THEY WERE SHOWING SEVERAL DAYS AGO. WITH THIS WEAKER MORE PROGRESSIVE SYSTEM...WILL KEEP THE FORECAST DRY FOR NOW. MODELS HAVE SOME DIFFERENCES WITH THE TIMING OF A COLD FRONT ON FRIDAY. WILL STICK TO THE ECMWF FOR NOW...SHOWING A LITTLE FASTER FRONT AND A LITTLE COOLER TEMPERATURES FOR FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 44 56 33 59 35 / 70 30 5 0 0 SAN ANGELO 45 62 35 62 32 / 40 20 0 0 0 JUNCTION 47 64 33 63 30 / 40 20 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUBER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1037 AM EST TUE FEB 12 2013 .SYNOPSIS... A STALLED FRONT SOUTH OF THE FORECAST AREA WILL BECOME A WARM FRONT AS LOW PRESSURE DEVELOPS IN THE LOWER MISSISSIPPI RIVER VALLEY. THE LOW WILL BE NEAR THE FORECAST AREA WEDNESDAY. WEAK HIGH PRESSURE WILL DOMINATE THURSDAY AND FRIDAY BEHIND THE LOW LIFTING NORTHEAST OF THE AREA. && .NEAR TERM /THROUGH TONIGHT/... TODAY...THE FRONT WILL REMAIN STALLED SOUTH OF THE AREA THIS AFTERNOON. RAIN COVERAGE HAS DIMINISHED BEHIND A MID-LEVEL SHORTWAVE TROUGH. COVERAGE MAY INCREASE AGAIN LATE IN THE DAY AS STRONGER ISENTROPIC LIFT DEVELOPS AHEAD OF THE DEVELOPING WARM FRONT. THE TEMPERATURE FORECAST APPEARS ON TRACK WITH HIGHS MAINLY IN THE LOWER 60S. TONIGHT...THE WATER VAPOR IMAGERY SHOWED A STRONG SHORTWAVE TROUGH OVER EAST TEXAS WHICH SHOULD HELP CAUSE LOW PRESSURE TO DEVELOP IN THE LOWER MISSISSIPPI RIVER VALLEY. THE STALLED FRONT TO OUR SOUTH WILL BECOME A WARM FRONT. THE MODELS SHOW STRONG ISENTROPIC LIFT OVER OUR AREA TONIGHT NORTH OF THE FRONT. THE NAM AND GFS PLUS SREF GUIDANCE INDICATE RAINFALL OF 0.75 TO 1.25 OF AN INCH OF RAIN TONIGHT. THE NAM LI PATTERN SUGGESTS THE WARM FRONT WILL REMAIN TO OUR SOUTH OVERNIGHT AND SHOWS SURFACE-BASED LI/S ABOVE ZERO. HOWEVER...THE NAM SHOWS STEEP LAPSE RATES ALOFT WITH CROSS TOTALS INCREASING TO AROUND 26. THERE MAY BE A FEW ELEVATED THUNDERSTORMS. WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... THE MODELS SHOW LOW PRESSURE NEAR THE FORECAST AREA WEDNESDAY WITH DEEPER MOISTURE SHIFTING EAST OF THE AREA. THE RAIN CHANCE SHOULD DIMINISH FROM WEST TO EAST. THE LOW WILL BE LIFTING NORTHEAST OF THE AREA WEDNESDAY NIGHT WITH DRY RIDGING DOMINATING THURSDAY. WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /THURSDAY THROUGH MONDAY/... THE GFS AND ECMWF SHOWED WEAK RIDGING CONTINUING TO DOMINATE FRIDAY. THE GFS WAS MORE PRONOUNCED WITH A FRONT AND ASSOCIATED MOISTURE SATURDAY INTO SATURDAY NIGHT COMPARED TO THE ECMWF. THE GFS AND ECMWF MOS POPS WERE CONSISTENT WITH VERY LOW POPS. WE KEPT THE FORECAST DRY. THE GFS AND ECMWF MOS SUPPORTED NEAR NORMAL TEMPERATURES FRIDAY BECOMING BELOW NORMAL SATURDAY. && .AVIATION /15Z TUESDAY THROUGH SUNDAY/... WEAK HIGH PRESSURE WILL RIDGE INTO THE AREA FROM THE NORTH TODAY. A COLD FRONT ALONG THE GULF COAST STATES WILL MOVE NORTHWARD TONIGHT. LOW PRESSURE WILL DEVELOP ALONG THE FRONT...AND CROSS THE TAF SITES WEDNESDAY. PREVAILING VFR CONDITIONS ACROSS THE TAF SITES THROUGH SUNSET. LATEST REGIONAL COMPOSITE RADAR SHOWING RAIN HAS MOVED EAST OF THE TAF SITES...BUT LATEST RUC IS INDICATING MORE RAIN WILL BE DEVELOPING OVER THE AREA BY LATE AFTERNOON OR EARLY THIS EVENING. WINDS WILL SHIFT TO THE NORTHEAST BY EARLY AFTERNOON. WILL SEE SOME BREAKS IN THE CLOUDS FOR MOST OF THE TAF SITES AT LEAST INTO THE EARLY AFTERNOON HOURS. AFTER SUNSET DEEP MOISTURE AND LIFT RETURNING TO ALL TAF SITES AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. EXPECT WIDESPREAD MVFR CONDITIONS AROUND 13/00Z TO LOWER TO IFR DURING THE EVENING. EXTENDED AVIATION OUTLOOK...HIGH CONFIDENCE FOR MVFR OR LOWER CONDITIONS THROUGH WEDNESDAY EVENING AS A LOW PRESSURE SYSTEM CROSSES THE REGION. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
545 AM CST TUE FEB 12 2013 ...UPDATED AVIATION SECTION... .SYNOPSIS... ISSUED AT 1124 PM CST MON FEB 11 2013 AT 00Z TUESDAY A 300MB JET STREAK EXTENDED FROM OLD MEXICO INTO NORTHEAST TEXAS. A -32C TO -33C 500MB TROUGH STRETCHED FROM NORTHEAST COLORADO INTO EAST CENTRAL ARIZONA AND THE 12 HOUR HEIGHT TENDENCIES INDICATED THE BETTER HEIGHT FALLS AT THE 500MB LEVEL WAS ACROSS NEW MEXICO. A 700MB TROUGH EXTENDED FROM NORTHEAST COLORADO INTO EASTERN ARIZONA. AT THE 850MB LEVEL THE BETTER MOISTURE RETURN AS OF 00Z TUESDAY APPEARS TO BE LOCATED ACROSS SOUTHERN TEXAS. AMARILLO UPPER AIR SOUNDING AT 00Z DID INDICATED A WEDGE OF MOISTURE AROUND THE 650MB LEVEL OR AROUND 12000FT MSL/9000FT ASL. AT THE SURFACE AN AREA OF HIGH PRESSURE WAS LOCATED ACROSS NORTHWEST KANSAS WITH A SURFACE BOUNDARY EXTENDING SOUTH FROM EASTERN COLORADO ACROSS EASTERN NEW MEXICO INTO SOUTHWEST TEXAS. && .UPDATE... ISSUED AT 441 AM CST TUE FEB 12 2013 OVER THE LAST SEVERAL HOURS THE STEADIER AND HEAVIER PRECIPITATION RELATED FAIRLY WELL WITH THE RAP 700MB BAROCLINIC ZONE THAT WAS MOVING ACROSS SOUTHWEST KANSAS. USING THIS AS A GUIDE AND BASED ON THE 06Z NAM I290 ISENTROPIC LIFT ALONG WITH THE LOCATION OF THE 300MB JET STEAK HAVE DECIDED TO CANCEL WHAT IS LEFT OF THE WINTER WEATHER ADVISORY. ALTHOUGH PERIODS OF LIGHT SNOW WILL BE POSSIBLE ACROSS SOUTH CENTRAL KANSAS THIS MORNING, IT CURRENTLY APPEARS SNOW ACCUMULATIONS WILL END UP BEING LESS THAN TWO INCHES. THE HIGHER SNOW ACCUMULATIONS STILL WILL BE NEAR THE OKLAHOMA BORDER AND WOULD NOT BE SURPRISED TO SEE A FEW 2 INCH REPORTS SOUTH OF BUTTERMILK OR NEAR KIOWA IN SOUTHEAST BARBER COUNTY. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 143 AM CST TUE FEB 12 2013 700MB TROUGH/MID LEVEL BAROCLINIC ZONE WILL CROSS SOUTHWEST KANSAS EARLY THIS MORNING. LOW LEVEL MOISTURE AND ISENTROPIC LIFT IN THE I290 TO I300 LEVEL ARE FORECAST TO IMPROVE AHEAD OF THIS 700MB TROUGH. BASED ON MOST RECENT RADAR RETURNS, SURFACE OBSERVATIONS/REPORTS, AND LATEST SATELLITE PRECIPITATION ESTIMATES WILL CONTINUE WITH THE CURRENT WINTER WEATHER ADVISORY EARLY THIS MORNING. THE MID LEVEL BAROCLNIC ZONE IS CURRENTLY FORECAST TO MOVE INTO THE TEXAS PANHANDLE AND NORTHWEST OKLAHOMA EARLY THIS AFTERNOON, AND THE BETTER ISENTROPIC LIFT IS CURRENTLY FORECAST TO SHIFT SOUTH OF THE OKLAHOMA BORDER. AT THE I29O ISENTROPIC SURFACE AT 18Z THERE IS EVEN A HINT OF DOWNGLIDE DEVELOPING ACROSS FAR WESTERN KANSAS. WILL THEREFORE BEGIN TO TAPER PRECIPITATION OFF FROM WEST TO EAST DURING THE AFTERNOON AS THE MID LEVEL TROUGH MOVES EAST/SOUTHEAST. ADDITIONAL SNOW ACCUMULATIONS FROM LATE MORNING INTO THE LATE AFTERNOON ACROSS THE SOUTHERN TIER OF KANSAS CURRENTLY APPEARS TO BE AN ONE INCH OR LESS BASED ON HOW QUICKLY THE 700MB TROUGH MOVES SOUTHEAST ALONG WITH THE LOCATION OF THE UPPER LEVEL JET, 850MB WARM AIR ADVECTION, AND ISENTROPIC LIFT. A FEW LOCATIONS COULD HAVE SNOW AMOUNTS AROUND 2 INCHES IN SOUTHERN COMANCHE AND BARBER COUNTIES. THERE WILL BE LITTLE DIURNAL CHANGE IN TEMPERATURES TODAY WHERE CLOUDS AND SNOW ARE EXPECTED. WILL THEREFORE UNDERCUT GUIDANCE AND KEEP AFTERNOON HIGHS MAINLY IN THE 30S. FURTHER NORTH AND NORTHWEST WHERE CLEARING SKIES ARE ANTICIPATED WILL TREND TOWARDS THE WARMER 850MB MIX DOWN TEMPERATURES WHICH WOULD YIELD HIGHS IN THE LOW TO MID 40S. TONIGHT WHERE SNOW ACCUMULATIONS OF ONE INCH OR MORE IS EXPECTED HAVE UNDERCUT GUIDANCE AND LOWERED MINIMUMS INTO THE TEENS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 321 AM CST TUE FEB 12 2013 TRANQUIL WEATHER IS ANTICIPATED WEDNESDAY AS HIGH PRESSURE TREKS EASTWARD ACROSS THE SOUTHERN PLAINS. MOSTLY CLEAR SKIES AND DRY CONDITIONS ARE FORECASTED DURING THIS PERIOD WITH NORTHWEST WINDS BECOMING BREEZY DURING THE AFTERNOON. HIGHS ARE FORECASTED REACH INTO THE UPPER 40S TO AROUND 50 DEGREES WITH THE EXCEPTION OF ALONG THE KS/OK BORDER WHERE MID 40S WILL BE POSSIBLE DUE TO SNOW ON THE GROUND. LOWS THURSDAY MORNING ARE ANTICIPATED TO FALL INTO THE MID TO UPPER 20S. MEANWHILE, AN UPPER LEVEL SHORTWAVE WILL MOVE DOWN THROUGH THE NORTHERN ROCKIES AND NORTHERN PLAINS WEDNESDAY NIGHT THEN INTO THE CENTRAL PLAINS THURSDAY. THIS WILL IN TURN HELP PUSH A COLD FRONT THROUGH WESTERN KANSAS THURSDAY AFTERNOON. MID LEVELS SATURATE AS THIS FRONT MOVES THROUGH THE AREA INCREASING CLOUD COVER ACROSS WESTERN KANSAS. I HAVE CONTINUED A SLIGHT CHANCE OF SNOW SHOWERS ACROSS FAR WESTERN KANSAS THURSDAY WITH THE REMAINDER OF WESTERN KANSAS REMAINING DRY. BREEZY NORTHERLY WINDS ARE ANTICIPATED BEHIND THE COLD FRONT WITH HIGHS IN THE MID 40S. LOWS BY FRIDAY MORNING LOOK TO RANGE FROM THE LOWER 20S ACROSS WEST CENTRAL KANSAS TO UPPER 20S ACROSS SOUTH CENTRAL KANSAS. HIGH PRESSURE BUILDS INTO THE AREA ON FRIDAY WITH DECREASING CLOUDS. COLDER TEMPERATURES ARE FORECASTED FRIDAY WITH HIGHS ONLY REACHING TO AROUND 40 DEGREES. UPPER LEVEL RIDGING THEN BUILDS ACROSS THE PLAINS THIS WEEKEND WITH HIGH PRESSURE BEING THE DOMINATING FEATURE AT THE SURFACE. THIS WILL BRING PARTLY CLOUDY SKIES AND DRY CONDITIONS TO WESTERN KANSAS. LOWS SLOWLY INCREASE EACH MORNING WITH LOWER 20S SATURDAY MORNING, MID TO UPPER 20S SUNDAY MORNING, AND LOWER 30S MONDAY MORNING. HIGHS THIS WEEKEND ARE FORECASTED TO BE IN THE MID TO UPPER 40S SATURDAY THEN IN THE 50S ON SUNDAY. MODELS SUGGEST AN UPPER LEVEL SHORTWAVE TO MOVE INTO THE CENTRAL ROCKIES ON MONDAY. IF THIS VERIFIES, THIS WILL BRING A COLD FRONT THROUGH WESTERN KANSAS AS THE DAY PROGRESSES WITH INCREASED CLOUD COVER. MODELS ALSO SUGGEST A SLIGHT CHANCE OF SHOWERS MONDAY AFTERNOON INTO MONDAY NIGHT MAINLY ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. HIGHS MONDAY ARE FORECASTED TO BE IN THE 40S WITH LOWER 50S ACROSS SOUTH CENTRAL KANSAS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 540 AM CST TUE FEB 12 2013 LIGHT SNOW SHOWERS WILL BE POSSIBLE ACROSS THE DODGE CITY TERMINAL OVER THE NEXT COUPLE OF HOURS WITH MVFR CONDITIONS AOA025. OTHERWISE EXPECT DECREASING HIGH CLOUDS AOA100 AS THE DAY PROGRESSES. WINDS WILL BE LIGHT AND VARIABLE BECOMING NORTHWEST AT 5 TO 10 KNOTS THIS AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 40 20 48 28 / 20 10 0 0 GCK 43 18 49 26 / 10 0 0 0 EHA 35 17 44 26 / 20 0 0 0 LBL 36 17 44 25 / 70 10 0 0 HYS 48 19 51 29 / 0 0 0 0 P28 37 18 45 29 / 40 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR KSZ086>090. && $$ UPDATE...BURGERT SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...HOVORKA_42 AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
444 AM CST TUE FEB 12 2013 ...UPDATED TO REMOVE REMAINING WINTER WEATHER ADVISORY... .SYNOPSIS... ISSUED AT 1124 PM CST MON FEB 11 2013 AT 00Z TUESDAY A 300MB JET STREAK EXTENDED FROM OLD MEXICO INTO NORTHEAST TEXAS. A -32C TO -33C 500MB TROUGH STRETCHED FROM NORTHEAST COLORADO INTO EAST CENTRAL ARIZONA AND THE 12 HOUR HEIGHT TENDENCIES INDICATED THE BETTER HEIGHT FALLS AT THE 500MB LEVEL WAS ACROSS NEW MEXICO. A 700MB TROUGH EXTENDED FROM NORTHEAST COLORADO INTO EASTERN ARIZONA. AT THE 850MB LEVEL THE BETTER MOISTURE RETURN AS OF 00Z TUESDAY APPEARS TO BE LOCATED ACROSS SOUTHERN TEXAS. AMARILLO UPPER AIR SOUNDING AT 00Z DID INDICATED A WEDGE OF MOISTURE AROUND THE 650MB LEVEL OR AROUND 12000FT MSL/9000FT ASL. AT THE SURFACE AN AREA OF HIGH PRESSURE WAS LOCATED ACROSS NORTHWEST KANSAS WITH A SURFACE BOUNDARY EXTENDING SOUTH FROM EASTERN COLORADO ACROSS EASTERN NEW MEXICO INTO SOUTHWEST TEXAS. && .UPDATE... ISSUED AT 441 AM CST TUE FEB 12 2013 OVER THE LAST SEVERAL HOURS THE STEADIER AND HEAVIER PRECIPITATION RELATED FAIRLY WELL WITH THE RAP 700MB BAROCLINIC ZONE THAT WAS MOVING ACROSS SOUTHWEST KANSAS. USING THIS AS A GUIDE AND BASED ON THE 06Z NAM I290 ISENTROPIC LIFT ALONG WITH THE LOCATION OF THE 300MB JET STEAK HAVE DECIDED TO CANCEL WHAT IS LEFT OF THE WINTER WEATHER ADVISORY. ALTHOUGH PERIODS OF LIGHT SNOW WILL BE POSSIBLE ACROSS SOUTH CENTRAL KANSAS THIS MORNING, IT CURRENTLY APPEARS SNOW ACCUMULATIONS WILL END UP BEING LESS THAN TWO INCHES. THE HIGHER SNOW ACCUMULATIONS STILL WILL BE NEAR THE OKLAHOMA BORDER AND WOULD NOT BE SURPRISED TO SEE A FEW 2 INCH REPORTS SOUTH OF BUTTERMILK OR NEAR KIOWA IN SOUTHEAST BARBER COUNTY. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 143 AM CST TUE FEB 12 2013 700MB TROUGH/MID LEVEL BAROCLINIC ZONE WILL CROSS SOUTHWEST KANSAS EARLY THIS MORNING. LOW LEVEL MOISTURE AND ISENTROPIC LIFT IN THE I290 TO I300 LEVEL ARE FORECAST TO IMPROVE AHEAD OF THIS 700MB TROUGH. BASED ON MOST RECENT RADAR RETURNS, SURFACE OBSERVATIONS/REPORTS, AND LATEST SATELLITE PRECIPITATION ESTIMATES WILL CONTINUE WITH THE CURRENT WINTER WEATHER ADVISORY EARLY THIS MORNING. THE MID LEVEL BAROCLNIC ZONE IS CURRENTLY FORECAST TO MOVE INTO THE TEXAS PANHANDLE AND NORTHWEST OKLAHOMA EARLY THIS AFTERNOON, AND THE BETTER ISENTROPIC LIFT IS CURRENTLY FORECAST TO SHIFT SOUTH OF THE OKLAHOMA BORDER. AT THE I29O ISENTROPIC SURFACE AT 18Z THERE IS EVEN A HINT OF DOWNGLIDE DEVELOPING ACROSS FAR WESTERN KANSAS. WILL THEREFORE BEGIN TO TAPER PRECIPITATION OFF FROM WEST TO EAST DURING THE AFTERNOON AS THE MID LEVEL TROUGH MOVES EAST/SOUTHEAST. ADDITIONAL SNOW ACCUMULATIONS FROM LATE MORNING INTO THE LATE AFTERNOON ACROSS THE SOUTHERN TIER OF KANSAS CURRENTLY APPEARS TO BE AN ONE INCH OR LESS BASED ON HOW QUICKLY THE 700MB TROUGH MOVES SOUTHEAST ALONG WITH THE LOCATION OF THE UPPER LEVEL JET, 850MB WARM AIR ADVECTION, AND ISENTROPIC LIFT. A FEW LOCATIONS COULD HAVE SNOW AMOUNTS AROUND 2 INCHES IN SOUTHERN COMANCHE AND BARBER COUNTIES. THERE WILL BE LITTLE DIURNAL CHANGE IN TEMPERATURES TODAY WHERE CLOUDS AND SNOW ARE EXPECTED. WILL THEREFORE UNDERCUT GUIDANCE AND KEEP AFTERNOON HIGHS MAINLY IN THE 30S. FURTHER NORTH AND NORTHWEST WHERE CLEARING SKIES ARE ANTICIPATED WILL TREND TOWARDS THE WARMER 850MB MIXDOWN TEMPERATURES WHICH WOULD YIELD HIGHS IN THE LOW TO MID 40S. TONIGHT WHERE SNOW ACCUMULATIONS OF ONE INCH OR MORE IS EXPECTED HAVE UNDERCUT GUIDANCE AND LOWERED MINIMUMS INTO THE TEENS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 321 AM CST TUE FEB 12 2013 TRANQUIL WEATHER IS ANTICIPATED WEDNESDAY AS HIGH PRESSURE TREKS EASTWARD ACROSS THE SOUTHERN PLAINS. MOSTLY CLEAR SKIES AND DRY CONDITIONS ARE FORECASTED DURING THIS PERIOD WITH NORTHWEST WINDS BECOMING BREEZY DURING THE AFTERNOON. HIGHS ARE FORECASTED REACH INTO THE UPPER 40S TO AROUND 50 DEGREES WITH THE EXCEPTION OF ALONG THE KS/OK BORDER WHERE MID 40S WILL BE POSSIBLE DUE TO SNOW ON THE GROUND. LOWS THURSDAY MORNING ARE ANTICIPATED TO FALL INTO THE MID TO UPPER 20S. MEANWHILE, AN UPPER LEVEL SHORTWAVE WILL MOVE DOWN THROUGH THE NORTHERN ROCKIES AND NORTHERN PLAINS WEDNESDAY NIGHT THEN INTO THE CENTRAL PLAINS THURSDAY. THIS WILL IN TURN HELP PUSH A COLD FRONT THROUGH WESTERN KANSAS THURSDAY AFTERNOON. MID LEVELS SATURATE AS THIS FRONT MOVES THROUGH THE AREA INCREASING CLOUD COVER ACROSS WESTERN KANSAS. I HAVE CONTINUED A SLIGHT CHANCE OF SNOW SHOWERS ACROSS FAR WESTERN KANSAS THURSDAY WITH THE REMAINDER OF WESTERN KANSAS REMAINING DRY. BREEZY NORTHERLY WINDS ARE ANTICIPATED BEHIND THE COLD FRONT WITH HIGHS IN THE MID 40S. LOWS BY FRIDAY MORNING LOOK TO RANGE FROM THE LOWER 20S ACROSS WEST CENTRAL KANSAS TO UPPER 20S ACROSS SOUTH CENTRAL KANSAS. HIGH PRESSURE BUILDS INTO THE AREA ON FRIDAY WITH DECREASING CLOUDS. COLDER TEMPERATURES ARE FORECASTED FRIDAY WITH HIGHS ONLY REACHING TO AROUND 40 DEGREES. UPPER LEVEL RIDGING THEN BUILDS ACROSS THE PLAINS THIS WEEKEND WITH HIGH PRESSURE BEING THE DOMINATING FEATURE AT THE SURFACE. THIS WILL BRING PARTLY CLOUDY SKIES AND DRY CONDITIONS TO WESTERN KANSAS. LOWS SLOWLY INCREASE EACH MORNING WITH LOWER 20S SATURDAY MORNING, MID TO UPPER 20S SUNDAY MORNING, AND LOWER 30S MONDAY MORNING. HIGHS THIS WEEKEND ARE FORECASTED TO BE IN THE MID TO UPPER 40S SATURDAY THEN IN THE 50S ON SUNDAY. MODELS SUGGEST AN UPPER LEVEL SHORTWAVE TO MOVE INTO THE CENTRAL ROCKIES ON MONDAY. IF THIS VERIFIES, THIS WILL BRING A COLD FRONT THROUGH WESTERN KANSAS AS THE DAY PROGRESSES WITH INCREASED CLOUD COVER. MODELS ALSO SUGGEST A SLIGHT CHANCE OF SHOWERS MONDAY AFTERNOON INTO MONDAY NIGHT MAINLY ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. HIGHS MONDAY ARE FORECASTED TO BE IN THE 40S WITH LOWER 50S ACROSS SOUTH CENTRAL KANSAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1124 PM CST MON FEB 11 2013 MID LEVEL MOISTURE WILL THICKEN AND LOWER EARLY THIS MORNING AS A 700MB TROUGH MOVES SOUTHEAST ACROSS WESTERN KANSAS. AT THIS TIME BASED ON THE LATEST BUFR SOUNDINGS THE CLOUD BASES WILL STAY ABOVE THE 850MB LEVEL SO VFR CIGS ARE EXPECTED ALONG AND AHEAD OF THE 700MB TROUGH. GIVEN THE DRY LAYER PRESENT BELOW THE 850MB LEVEL THE PRECIPITATION CHANCES DO NOT LOOK VERY GOOD AT DDC OR GCK SO HAVE DECIDED TO REMOVE PRECIPITATION CHANCES. WINDS AT LESS THAN 10 KNOTS WILL PERSIST THROUGH MID DAY TUESDAY AS AN AREA OF HIGH PRESSURE AT THE SURFACE CROSSES THE CENTRAL PLAINS. && .PRELIMINARY POINT TEMPS/POPS... DDC 40 20 48 28 / 20 10 0 0 GCK 43 18 49 26 / 10 0 0 0 EHA 35 17 44 26 / 20 0 0 0 LBL 36 17 44 25 / 70 10 0 0 HYS 48 19 51 29 / 0 0 0 0 P28 37 18 45 29 / 40 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BURGERT SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...HOVORKA_42 AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
922 AM EST TUE FEB 12 2013 .SYNOPSIS... A GUSTY WESTERLY FLOW WILL PREVAIL TODAY BEFORE A WEAK AREA OF HIGH PRESSURE ARRIVES TONIGHT. LOW PRESSURE MOVING THROUGH THE GULF COAST STATES EARLY WEDNESDAY WILL TRACK NORTHEAST TO A POSITION OFF THE DELMARVA PENINSULA BY LATE WEDNESDAY NIGHT. CONFIDENCE IS INCREASING ON A LIGHT TO MODERATE SNOW ACCUMULATION ACROSS SOUTH-CENTRAL PENNSYLVANIA WITH THIS SYSTEM. THE WEATHER PATTERN IS EXPECTED TO TURN COLDER INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... EARLY VIZ SHOTS SHOW A TYPICAL POST COLD FRONTAL SHIELD OF STRATO- CU ALONG WITH SOME LIGHT SNOW SHOWERS OVER THE NW. EXPECTING SLOW IMPROVEMENT TODAY AS WEAK HIGH PRESSURE BEGINS TO MAKE INROADS INTO THE REGION...SO NO SIG CHANGES MADE TO THE FCST WITH THIS UPDATE. PREVIOUS DISCUSSION... SHRTWV TROUGH AXIS WILL ROTATE ACRS N-CENTRAL PA EARLY THIS MORNING. LOW-LEVEL CAA/STEEP LAPSE RATES AND WLY TRAJECTORY WILL SUPPORT OCNL UPSLOPE -SHSN OVER THE ALLEGHENY PLATEAU/NW MTNS EARLY TODAY. LITTLE TO NO ACCUM EXPECTED. RAP BUFKIT SOUNDINGS SHOW INVERSION HGTS LOWERING THRU THE MORNING...WITH INCREASING SUBSIDENCE IN WAKE OF SHRTWV/AREA OF HIGH PRES DRIFTING ENEWD FROM THE MID OH VLY. THIS SHOULD BRING AN END TO -SHSN ACTIVITY AROUND MID-DAY WITH JUST SOME SCT FLURRIES EXPECTED TO LINGER OVER THE NW MTNS INTO THE AFTN. THE LOW-LEVEL CAA/STEEP LAPSE RATES WILL MAINTAIN GUSTY WLY WINDS INTO THE AFTN. THE WIND ADVY HAS BEEN ALLOWED TO EXPIRE. IN GENERAL...RAP SOUNDINGS SHOW PEAK GUSTS MAINLY IN THE 30-35KT RANGE WITH LOCALLY HIGHER GUSTS PSBL ON THE RIDGES. BKN-OVC STRATOCU WILL COVER THE N/W MTNS THRU THE AFTN WITH TEMPS IN THE LOW TO MID 30S. DOWNSLOPE FLOW E OF THE ALLEGHENY FRONT SHOULD HELP TO PROVIDE PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL RIDGE/VALLEY REGION AND SUSQ VLY...WITH TEMPS VARYING FROM THE UPPER 30S TO LOW 40S. WEAK HIGH PRES WILL DRIFT NEWD OVER THE AREA TONIGHT WITH M/CLR SKIES...LGT WINDS AND TEMPS MAINLY IN THE 20S. MID-HIGH LVL CLOUDS SHOULD BEGIN TO INCREASE FROM THE SOUTH BY DAYBREAK WED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WEAK SFC HIGH OVER EAST CENTRAL PA WILL RETREAT NEWD BY WEDNESDAY NIGHT AS A FAIRLY DISORGANIZED AREA OF LOW PRESSURE TRACKS OFF OF THE NC COAST AND OUT TO SEA WELL SOUTH OF LONG ISLAND AND CAPE COD. MAIN CHALLENGE FOR THE MEDIUM RANGE WILL BE TO ASCERTAIN THE IMPACTS OF THIS SYSTEM...AND PARTICULARLY THE NORTHERN EXTENT OF SIGNIFICANT SNOWFALL WEDNESDAY AFTERNOON AND NIGHT. 00Z DETERMINISTIC GUIDANCE COUPLED WITH 00Z GEFS EXAMINATION SHOWS A REASONABLE LIKELIHOOD OF ADVISORY CRITERIA SNOWFALL ACROSS THE SOUTHERN HALF OF CENTRAL PA. MARGINAL BOUNDARY LAYER TEMPERATURES AT THE ONSET OF PRECIPITATION WEDNESDAY AFTERNOON WILL CUT DOWN ON ACCUMS AND IF MEAN QPF WEREN`T A LIMITING FACTOR TO RULE OUT A WATCH AT THIS TIME...MARGINAL PBL TEMPERATURES WOULD BE...THUS NO WATCHES AT THIS TIME. AGAIN WENT WITH A BLEND OF OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND...PRODUCING A MAINLY LIGHT SNOWFALL WED AFTN AND NIGHT. NCEP WWD GRAPHICS DEPICT A 3-6 INCH STRIPE OVER MY SOUTHEAST COUNTIES WHICH I THINK IS SLIGHTLY OVERDONE GIVEN THE MELTING EXPECTED TO OCCUR AT THE ONSET. SNOW SHOULD BEGIN LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. 00Z GFS AND NAM12 IN REMARKABLE AGREEMENT ON PLACEMENT OF 0.25" QPF CONTOUR...FROM KJST TO KAOO EASTWARD TO KMDT. AREAS SOUTH WILL SEE UP TO .5" W.E. AND WILL AGAIN DEAL WITH MELTING FROM MARGINALLY COLD BOUNDARY LAYER/SFC TEMPS. THE MAGNITUDE OF THIS EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE. && .LONG TERM /THURSDAY THROUGH MONDAY/... AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... GUSTY NW FLOW PATTERN WILL BRING THE USUAL LOWER CIGS INTO THE WRN AIRFIELDS WITH SCT-BKN LOW VFR PREVAILING E OF THE ALLEGHENY FRONT. EXPECT SFC WIND GUSTS IN THE 25-35KT RANGE THROUGH THE DAY BEFORE SUBSIDING LATER THIS EVE AND INTO TONIGHT. A WEAK AREA OF HIGH PRES WILL PROVIDE VFR FLYING TONIGHT WITH MID-HIGH CLOUDS INCREASING AHEAD OF LOW PRESSURE DEVELOPING OVER THE GULF COAST STATES. THIS LOW IS EXPECTED TO TRACK ENE TO A POSITION OFF THE DELMARVA PENINSULA BY EARLY THURSDAY MORNING...WITH A BAND OF SNOW ON THE NW SIDE OF THE LOW TRACK LKLY IMPACTING S-CENTRAL PA TERMINALS. OUTLOOK... WED...IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA. THU...MVFR/SHSN WEST. BCMG VFR CENTRAL/EAST. FRI-SAT...MVFR/SHSN WEST. VFR CENTRAL/EAST. GUSTY WNW WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/STEINBUGL NEAR TERM...LA CORTE/STEINBUGL SHORT TERM...DEVOIR LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
705 AM EST TUE FEB 12 2013 .SYNOPSIS... A GUSTY WESTERLY FLOW WILL PREVAIL TODAY BEFORE A WEAK AREA OF HIGH PRESSURE ARRIVES TONIGHT. LOW PRESSURE MOVING THROUGH THE GULF COAST STATES EARLY WEDNESDAY WILL TRACK NORTHEAST TO A POSITION OFF THE DELMARVA PENINSULA BY LATE WEDNESDAY NIGHT. CONFIDENCE IS INCREASING ON A LIGHT TO MODERATE SNOW ACCUMULATION ACROSS SOUTH-CENTRAL PENNSYLVANIA WITH THE MID-WEEK SYSTEM. THE WEATHER PATTERN IS EXPECTED TO TURN COLDER INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 12Z UPDATE...NO SIGNIFICANT CHANGES FOR FINAL OVERNIGHT UPDATE. MINS STAYED MUCH WARMER OVER THE SE ZONES DUE TO CLOUDS AND WINDS. MESO/SFC OBS STILL INDICATING PEAK GUSTS ARE BLW ADVY CRITERIA BUT WILL LET THE WIND ADVY RUN ITS COURSE AND EXPIRE AT 9AM. PREVIOUS DISCUSSION... SHRTWV TROUGH AXIS WILL ROTATE ACRS N-CENTRAL PA EARLY THIS MORNING. LOW-LEVEL CAA/STEEP LAPSE RATES AND WLY TRAJECTORY WILL SUPPORT OCNL UPSLOPE -SHSN OVER THE ALLEGHENY PLATEAU/NW MTNS EARLY TODAY. LITTLE TO NO ACCUM EXPECTED. RAP BUFKIT SOUNDINGS SHOW INVERSION HGTS LOWERING THRU THE MORNING...WITH INCREASING SUBSIDENCE IN WAKE OF SHRTWV/AREA OF HIGH PRES DRIFTING ENEWD FROM THE MID OH VLY. THIS SHOULD BRING AN END TO -SHSN ACTIVITY AROUND MID-DAY WITH JUST SOME SCT FLURRIES EXPECTED TO LINGER OVER THE NW MTNS INTO THE AFTN. THE LOW-LEVEL CAA/STEEP LAPSE RATES WILL MAINTAIN GUSTY WLY WINDS INTO THE AFTN. THE WIND ADVY LOOKS MARGINAL BASED ON MESONET DATA. TRIMMED COUNTIES NORTH OF I-80...BUT WILL CONTINUE THE ADVY FOR THE LAUREL HIGHLANDS/S-CENTRAL MTNS WHERE THE HIGHEST GUSTS ARE CURRENTLY BEING REPORTED. IN GENERAL...RAP SOUNDINGS SHOW PEAK GUSTS MAINLY IN THE 30-35KT RANGE WITH LOCALLY HIGHER GUSTS PSBL ON THE RIDGES. BKN-OVC STRATOCU WILL COVER THE N/W MTNS THRU THE AFTN WITH TEMPS IN THE LOW TO MID 30S. DOWNSLOPE FLOW E OF THE ALLEGHENY FRONT SHOULD HELP TO PROVIDE PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL RIDGE/VALLEY REGION AND SUSQ VLY...WITH TEMPS VARYING FROM THE UPPER 30S TO LOW 40S. WEAK HIGH PRES WILL DRIFT NEWD OVER THE AREA TONIGHT WITH M/CLR SKIES...LGT WINDS AND TEMPS MAINLY IN THE 20S. MID-HIGH LVL CLOUDS SHOULD BEGIN TO INCREASE FROM THE SOUTH BY DAYBREAK WED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WEAK SFC HIGH OVER EAST CENTRAL PA WILL RETREAT NEWD BY WEDNESDAY NIGHT AS A FAIRLY DISORGANIZED AREA OF LOW PRESSURE TRACKS OFF OF THE NC COAST AND OUT TO SEA WELL SOUTH OF LONG ISLAND AND CAPE COD. MAIN CHALLENGE FOR THE MEDIUM RANGE WILL BE TO ASCERTAIN THE IMPACTS OF THIS SYSTEM...AND PARTICULARLY THE NORTHERN EXTENT OF SIGNIFICANT SNOWFALL WEDNESDAY AFTERNOON AND NIGHT. 00Z DETERMINISTIC GUIDANCE COUPLED WITH 00Z GEFS EXAMINATION SHOWS A REASONABLE LIKELIHOOD OF ADVISORY CRITERIA SNOWFALL ACROSS THE SOUTHERN HALF OF CENTRAL PA. MARGINAL BOUNDARY LAYER TEMPERATURES AT THE ONSET OF PRECIPITATION WEDNESDAY AFTERNOON WILL CUT DOWN ON ACCUMS AND IF MEAN QPF WEREN`T A LIMITING FACTOR TO RULE OUT A WATCH AT THIS TIME...MARGINAL PBL TEMPERATURES WOULD BE...THUS NO WATCHS AT THIS TIME. AGAIN WENT WITH A BLEND OF OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND...PRODUCING A MAINLY LIGHT SNOWFALL WED AFTN AND NIGHT. NCEP WWD GRAPHICS DEPICT A 3-6 INCH STRIPE OVER MY SOUTHEAST COUNTIES WHICH I THINK IS SLIGHTLY OVERDONE GIVEN THE MELTING EXPECTED TO OCCUR AT THE ONSET. SNOW SHOULD BEGIN LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. 00Z GFS AND NAM12 IN REMARKABLE AGREEMENT ON PLACEMENT OF 0.25" QPF CONTOUR...FROM KJST TO KAOO EASTWARD TO KMDT. AREAS SOUTH WILL SEE UP TO .5" W.E. AND WILL AGAIN DEAL WITH MELTING FROM MARGINALLY COLD BOUNDARY LAYER/SFC TEMPS. THE MAGNITUDE OF THIS EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE. && .LONG TERM /THURSDAY THROUGH MONDAY/... AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... GUSTY NW FLOW PATTERN WILL BRING THE USUAL LOWER CIGS INTO THE WRN AIRFIELDS WITH SCT-BKN LOW VFR PREVAILING E OF THE ALLEGHENY FRONT. EXPECT SFC WIND GUSTS IN THE 25-35KT RANGE THROUGH THE DAY BEFORE SUBSIDING LATER THIS EVE AND INTO TONIGHT. A WEAK AREA OF HIGH PRES WILL PROVIDE VFR FLYING TONIGHT WITH MID-HIGH CLOUDS INCREASING AHEAD OF LOW PRESSURE DEVELOPING OVER THE GULF COAST STATES. THIS LOW IS EXPECTED TO TRACK ENE TO A POSITION OFF THE DELMARVA PENINSULA BY EARLY THURSDAY MORNING...WITH A BAND OF SNOW ON THE NW SIDE OF THE LOW TRACK LKLY IMPACTING S-CENTRAL PA TERMINALS. OUTLOOK... WED...IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA. THU...MVFR/SHSN WEST. BCMG VFR CENTRAL/EAST. FRI-SAT...MVFR/SHSN WEST. VFR CENTRAL/EAST. GUSTY WNW WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ024-025-033- 034. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...DEVOIR LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
519 AM EST TUE FEB 12 2013 .SYNOPSIS... A GUSTY WESTERLY FLOW WILL PREVAIL TODAY BEFORE A WEAK AREA OF HIGH PRESSURE ARRIVES TONIGHT. LOW PRESSURE MOVING THROUGH THE GULF COAST STATES EARLY WEDNESDAY WILL TRACK NORTHEAST TO A POSITION OFF THE DELMARVA PENINSULA BY LATE WEDNESDAY NIGHT. CONFIDENCE IS INCREASING ON A LIGHT TO MODERATE SNOW ACCUMULATION ACROSS SOUTH-CENTRAL PENNSYLVANIA WITH THE MID-WEEK SYSTEM. THE WEATHER PATTERN IS EXPECTED TO TURN COLDER INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SHRTWV TROUGH AXIS WILL ROTATE ACRS N-CENTRAL PA EARLY THIS MORNING. LOW-LEVEL CAA/STEEP LAPSE RATES AND WLY TRAJECTORY WILL SUPPORT OCNL UPSLOPE -SHSN OVER THE ALLEGHENY PLATEAU/NW MTNS EARLY TODAY. LITTLE TO NO ACCUM EXPECTED. RAP BUFKIT SOUNDINGS SHOW INVERSION HGTS LOWERING THRU THE MORNING...WITH INCREASING SUBSIDENCE IN WAKE OF SHRTWV/AREA OF HIGH PRES DRIFTING ENEWD FROM THE MID OH VLY. THIS SHOULD BRING AN END TO -SHSN ACTIVITY AROUND MID-DAY WITH JUST SOME SCT FLURRIES EXPECTED TO LINGER OVER THE NW MTNS INTO THE AFTN. THE LOW-LEVEL CAA/STEEP LAPSE RATES WILL MAINTAIN GUSTY WLY WINDS INTO THE AFTN. THE WIND ADVY LOOKS MARGINAL BASED ON MESONET DATA. TRIMMED COUNTIES NORTH OF I-80...BUT WILL CONTINUE THE ADVY FOR THE LAUREL HIGHLANDS/S-CENTRAL MTNS WHERE THE HIGHEST GUSTS ARE CURRENTLY BEING REPORTED. IN GENERAL...RAP SOUNDINGS SHOW PEAK GUSTS MAINLY IN THE 30-35KT RANGE WITH LOCALLY HIGHER GUSTS PSBL ON THE RIDGES. BKN-OVC STRATOCU WILL COVER THE N/W MTNS THRU THE AFTN WITH TEMPS IN THE LOW TO MID 30S. DOWNSLOPE FLOW E OF THE ALLEGHENY FRONT SHOULD HELP TO PROVIDE PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL RIDGE/VALLEY REGION AND SUSQ VLY...WITH TEMPS VARYING FROM THE UPPER 30S TO LOW 40S. WEAK HIGH PRES WILL DRIFT NEWD OVER THE AREA TONIGHT WITH M/CLR SKIES...LGT WINDS AND TEMPS MAINLY IN THE 20S. MID-HIGH LVL CLOUDS SHOULD BEGIN TO INCREASE FROM THE SOUTH BY DAYBREAK WED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WEAK SFC HIGH OVER EAST CENTRAL PA WILL RETREAT NEWD BY WEDNESDAY NIGHT AS A FAIRLY DISORGANIZED AREA OF LOW PRESSURE TRACKS OFF OF THE NC COAST AND OUT TO SEA WELL SOUTH OF LONG ISLAND AND CAPE COD. MAIN CHALLENGE FOR THE MEDIUM RANGE WILL BE TO ASCERTAIN THE IMPACTS OF THIS SYSTEM...AND PARTICULARLY THE NORTHERN EXTENT OF SIGNIFICANT SNOWFALL WEDNESDAY AFTERNOON AND NIGHT. 00Z DETERMINISTIC GUIDANCE COUPLED WITH 00Z GEFS EXAMINATION SHOWS A REASONABLE LIKELIHOOD OF ADVISORY CRITERIA SNOWFALL ACROSS THE SOUTHERN HALF OF CENTRAL PA. MARGINAL BOUNDARY LAYER TEMPERATURES AT THE ONSET OF PRECIPITATION WEDNESDAY AFTERNOON WILL CUT DOWN ON ACCUMS AND IF MEAN QPF WEREN`T A LIMITING FACTOR TO RULE OUT A WATCH AT THIS TIME...MARGINAL PBL TEMPERATURES WOULD BE...THUS NO WATCHS AT THIS TIME. AGAIN WENT WITH A BLEND OF OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND...PRODUCING A MAINLY LIGHT SNOWFALL WED AFTN AND NIGHT. NCEP WWD GRAPHICS DEPICT A 3-6 INCH STRIPE OVER MY SOUTHEAST COUNTIES WHICH I THINK IS SLIGHTLY OVERDONE GIVEN THE MELTING EXPECTED TO OCCUR AT THE ONSET. SNOW SHOULD BEGIN LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. 00Z GFS AND NAM12 IN REMARKABLE AGREEMENT ON PLACEMENT OF 0.25" QPF CONTOUR...FROM KJST TO KAOO EASTWARD TO KMDT. AREAS SOUTH WILL SEE UP TO .5" W.E. AND WILL AGAIN DEAL WITH MELTING FROM MARGINALLY COLD BOUNDARY LAYER/SFC TEMPS. THE MAGNITUDE OF THIS EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE. && .LONG TERM /THURSDAY THROUGH MONDAY/... AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... 09Z UPDATE...NO CHANGES TO 12/06Z TAFS. GUSTY NW FLOW PATTERN WILL BRING THE USUAL LOWER CIGS INTO THE WRN AIRFIELDS WITH SCT-BKN LOW VFR PREVAILING E OF THE ALLEGHENY FRONT. EXPECT SFC WIND GUSTS IN THE 25-40KT RANGE THROUGH THE DAY BEFORE SUBSIDING LATER THIS EVE AND INTO TONIGHT. A WEAK AREA OF HIGH PRES WILL PROVIDE VFR FLYING TONIGHT WITH MID-HIGH CLOUDS LKLY INCREASING AHEAD OF LOW PRESSURE DEVELOPING OVER THE GULF COAST STATES. THIS LOW IS EXPECTED TO TRACK ENE TO A POSITION OFF THE DELMARVA PENINSULA BY EARLY THURSDAY MORNING. OUTLOOK... WED...IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA. THU...MVFR/SHSN WEST. BCMG VFR CENTRAL/EAST. FRI-SAT...MVFR/SHSN WEST. VFR CENTRAL/EAST. GUSTY WNW WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ024-025-033- 034. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...DEVOIR LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1004 AM MST TUE FEB 12 2013 .UPDATE...SLOWER TEMPERATURE RECOVERY IN ZONES 30 AND 32 THIS MORNING...SO HAVE LOWERED THE FCST HIGH TEMPERATURES IN THOSE AREA TODAY...OTHERWISE THE REST OF THE FCST ON TRACK. && .AVIATION...NO SIGNIFICANT CHANGES PLANNED IN THE UPCOMING TAFS...FCST ON TRACK. && .PREV DISCUSSION... /ISSUED 246 AM MST TUE FEB 12 2013/ SHORT TERM...THE UPPER LEVEL TROUGH WILL MOVE SE OF THE AREA TODAY WITH THE FLOW ALOFT BECOMING MORE NLY AND THEN NNWLY TONIGHT. CROSS-SECTIONS SHOW SOME INCREASE IN MOISTURE OVER THE NRN MTNS BY TONIGHT HOWEVER WITH POOR LAPSE RATES ANY SNOW SHOULD BE VERY LIGHT AND CONFINED MAINLY TO ZN 31. OTHERWISE WILL KEEP THE REST OF THE RGN DRY THRU TONIGHT. AS FOR TEMPS 850-700 MB READINGS ONLY RISE A FEW DGREES TODAY SO WILL KEEP HIGHS IN THE UPPER 30S TO NEAR 40 ACROSS MOST OF NERN CO EXCEPT OVER THE FAR NERN CORNER WHERE LINGERING SNOW COVER MAY KEEP HIGHS IN THE LOWER 30S. LONG TERM...MODELS HAVE FAIRLY WEAK NORTHWESTERLY FLOW ALOFT ON WEDNESDAY. IT INCREASES WEDNESDAY NIGHT AND BECOMES MORE WESTERLY. ON THURSDAY...A MEAN UPPER TROUGH CONTINUES DEVELOPING OVER EASTERN NORTH AMERICA WITH STRONG NORTHWESTERLY FLOW ON IT`S BACKSIDE RIGHT OVER COLORADO. THERE IS AN UPPER TROUGH WITH FAILRY DECENT SYNOPTIC SCALE ENERGY EMBEDDED IN THE FLOW ON THURSDAY INTO THURSDAY NIGHT. THIS USHERS IN A COLD FRONT WITH UPSLOPE BEHIND IT FOR THE PLAINS AND FOOTHILLS ON THURSDAY. THE UPSLOPE FLOW CONTINUES MUCH OF THURSDAY NIGHT. THE LOW LEVEL FLOW ON WEDNESDAY AND WEDNESDAY NIGHT IS MAINLY DOWNSLOPING. FOR MOISTURE...MODELS SHOW SOME IN THE MOUTNIANS...AND A BIT OVER THE PLAINS. MOISTURE INCREASES OVER ALL THE CWA WEDNESDAY NIGHT. BY THURSDAY IT IS PRETTY DEEP OVER ALL THE CWA...THIS CONTINUES THURSDAY NIGHT. THE QPF FIELDS HAVE A TAD OF MEASURABLE SNOWFALL OVER THE MOUNTAINS WEDNESDAY AND WEDNESDAY NIGHT. ON THURSDAY ..THE AMOUNTS IN THE MOUNTAINS INCREASE A BIT...AND THERE IS A TAD OVER THE MOST OF THE PLAINS BY AFTERNOON. THERE ARE HIGHER AMOUNTS THURSDAY NIGHT OVER THE FOOTHILLS AND IMMEDIATE PLAINS. THERE IS A BIT OVER MOST AREAS AFTER MIDNIGHT THURSDAY NIGHT... EXCEPT FOR THE NORTHEAST CORNER. FOR POPS...THERE IS ENOUGH MOISTURE AND OROGRAPHIC HELP TO KEEP "CHANCE"S OF SNOW IN THE HIGH MOUNTAINS WEDNESDAY INTO WEDNESDAY EVENING...THEN "LIKELY"S INTO THURSDAY EVENING. BY LATER THURSDAY INTO THURSDAY NIGHT...THE UPSLOPE BEHIND THE COLD FRONT...ALONG WITH A FAIRLY DECENT BRIEF SHOT OF SYNOPTIC SCALE ENERGY...AND MOISTURE...WILL GO WITH "CHANCE"S OVER MOST OF THE PLAINS AS WELL. FOR TEMPERATURES... WEDNESDAY`S HIGHS LOOK TO BE 3.0-4.5 C WARMER THAN TODAY`S. THURSDAY`S WILL BE 2-5 C COLDER THAN WEDNESDAY`S. THE MOS GUIDANCE WEDNESDAY AND THURSDAY HIGH TEMPERATURES FOR DENVER DIFFER CONSIDERABLY BETWEEN THE GFS AND NAM. THE GFS IS 12 DEGREES F WARMER BOTH DAYS. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY ..MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE CWA FRIDAY INTO EARLY SATURDAY. BY SATURDAY MIDDAY INTO THE EVENING AN UPPER RIDGE MOVES ACROSS THE FORECAST AREA WITH WEAK ZONAL FLOW. THE ZONAL FLOW INCREASES IN SPEED ON SUNDAY...THEN THE NEXT UPPER TROUGH IS PROGGED TO MOVE ACROSS COLORADO ON MONDAY. THE MOISTURE DECREASES RAPIDLY ON FRIDAY. BOTH THE GFS AND ECMWF SHOW A DRY WEEKEND WITH WARMING TEMPERATURES. BOTH ALSO SHOW PRETTY DEEP MOISTURE...EVEN UPSLOPE FOR THE PLAINS WITH THE MONDAY SYSTEM. AVIATION...WINDS ARE DRAINAGE EARLY THIS MORNING. LATEST HRRR AND RAP SHOW WINDS BECOMING MORE NNW BY 19Z AND THEN MORE NNE BY 23Z. BY EARLY EVENING EXPECT A LIGHT ELY COMPONENT WHICH WILL GRADUALLY BECOME DRAINAGE BY 04Z. OTHERWISE SHOULD HAVE VFR CONDITIONS TODAY AND TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...COOPER LONG TERM....RJK AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
330 PM EST Tue Feb 12 2013 ...SEVERE WEATHER AND ADDITIONAL FLOODING POSSIBLE THIS EVENING INTO MIDDAY WEDNESDAY... .NEAR TERM [through Tonight]... A surface low was continuing to develop along the Gulf coast in the mid-afternoon, and at 20 UTC was centered somewhere just north of Lake Charles, Louisiana (SW LA). The stalled front that was draped to the east from this low was beginning to return north as a warm front. The warm front had only penetrated a minor distance inland in some spots, and stretched from the low, to New Orleans, to Mexico Beach, to St. Mark`s, to Madison FL. South of this boundary, partial clearing was occurring with temperatures reaching into the 70s and dewpoints quickly increasing into the upper 60s to around 70. This has allowed MLCAPE to slowly build along and just south of the warm front. However, destabilization will probably occur more in earnest this evening when stronger mid-upper level height falls spread east with the ejecting wave aloft, and a plume of steeper mid-level lapse rates advects east along the Gulf coast. Thunderstorms were already developing in the broad WAA regime from C MS to S GA. The nose of the strongest 0-2km moisture transport (and band of strongest low-level theta-e advection) will be near the track of the surface low, which at the moment appears as though it will be just to the northwest of our area. Therefore, the best large scale forcing for rain should be located just outside our forecast area, which is not bad news given the recent heavy rainfall. That being said, the highest probability of rain still looks to be closest to those forcing mechanisms in the northwest half of our area, which is also the area that received the heavy rain yesterday. Therefore, we will maintain the Flash Flood Watch overnight given the coincidence of highest PoPs and high soil moisture / low FFG. The isolated severe weather threat appears to still be on track. As the surface low develops ENE this evening, the surface warm front should shift north through the area drawing an unstable boundary layer air mass in. Model mean MLCAPE from the NAM, GFS, and ECMWF looks to be around 500 j/kg with about 60-70 knots of deep layer shear. This falls within a favorable parameter space for low-topped supercells and severe weather in our area, but there remain some uncertainties. Convection-allowing model (CAM) guidance has not shown very vigorous updrafts in any forecast thunderstorms in our area. Therefore, there is likely some sort of limiting factor - probably related to boundary layer stability - that will ultimately decide how intense the overnight convection is. The 00 UTC TAE sounding may reveal some important clues about any low-level stable layers or inversions that could inhibit the severe threat. Although a few scattered supercells are possible in the warm sector, we expect a trend towards a squall line or line segments along the trailing cold front with time tonight. Given an overall favorable juxtaposition of shear and instability, severe storms are certainly possible, but we expect impacts to be isolated and confined to only the strongest cells. As the warm front lifts north this evening and a warm, moist air mass advects into our area (as well as widespread cloud cover and occasional rain), we should see a mild night. Temperatures are expected to follow a non-diurnal trend and remain nearly steady. LAMP and RAP guidance was used to portray hourly temp trends. && .SHORT TERM [Wednesday Through Friday]... The severe weather threat will end from west to east ahead of the cold front that will push through Wednesday and Wednesday night. The severe weather threat will shift eastward encompassing most of our Georgia zones and the Florida Big Bend. The main concern will continue to be the potential for damaging thunderstorm winds although an isolated tornado is also possible. We will also be monitoring rainfall very closely as the ground is already or near saturated across SE AL and our northern and westernmost GA zones. Also, there is a potential for another 1 to 2 inches of rain in these areas and a Flood Watch will continue to be in effect. In the wake of the front, high pressure and a much drier airmass filter into the region. Max temps will be near seasonal levels with lows at or just below normal. && .LONG TERM [Friday Night through next Tuesday]... A broad upper trough will amplify over the eastern third of the CONUS Saturday with a dry cold front passing through the local region by late in the day. The upper flow becomes nearly zonal on Sunday with a cold and dry airmass settling in over the area. Surface high pressure is forecast to be centered across the Florida panhandle Sunday before sliding east and off the southeast U.S. coast Monday. Another upper level trough digs through the nation`s midsection Monday with induced ridging across the local area. The trough deamplifies as in moves through the Lower Mississippi Valley Tuesday but showers and thunderstorms are forecast to spread across the Tri-state region ahead of the cold front. Confidence is low on the timing of this system so will keep PoPs in the chance category. Colder than normal temps are expected over the weekend, especially Sunday with lows around 30 degrees and highs only in the mid 50s for most inland areas. Another light freeze is possible Monday morning followed by a gradual warming trend. && .AVIATION [through 18z Tuesday]... Although some brief MVFR may be possible at a few of the terminals where clouds temporarily thin this afternoon, widespread IFR is expected to prevail through the night and into early tomorrow morning. Occasional LIFR will be possible - both in low stratus and in any of the stronger thunderstorms that may occur overnight. Some of the storms may produce gusty winds, but for now limited gusts in the "TEMPO" groups to between 20 and 30 knots. Timing for that TEMPO group was based on a model consensus. && .MARINE... A surface low will track from the central Gulf coast this evening to near the Delmarva Peninsula by Wednesday evening and drag a southwest extending cold front across the local waters. Onshore winds will increase from west to east to advisory levels tonight ahead of the front. Winds will swing around to become offshore Wednesday afternoon and evening in the wake of the front with winds and seas gradually dropping below headline criteria. Light winds and low seas are expected through the reminder of the work week as high pressure builds over the waters. Winds and seas elevate to advisory levels once again in the wake of an arctic cold front over the weekend. && .FIRE WEATHER... Wet conditions are expected through Wednesday. Drier air will move in for Thursday and Friday with minimum RH values near or just below 35 percent across portions of inland northwest Florida. However, with wet soils overall, it seems unlikely that red flag conditions will be reached. && .HYDROLOGY... After a long stretch of quiet river conditions, things have certainly changed in a hurry. Extremely heavy rains across parts of Southeast Alabama Sunday night and Monday (radar estimates of over a foot in Geneva County) caused sharp rises along parts of the Choctawhatchee River, which is forecast to crest in the minor flood category at Geneva and Caryville and the moderate flood category at Bruce. Some of this heavy rain extended into Georgia as well, and downstream rises are also expected along the Apalachicola and Chipola Rivers. Currently the Apalachicola River at Blountstown is expected to crest in the minor flood category with the Chipola River at Marianna and Altha rising to action stage by late Friday into Saturday. The Kinchafoonee Creek is also expected to rise into the minor flood category in Lee county east of Dawson and remain just below minor flood stage up at Preston. An additional couple of inches of rain are expected across portions of southeast Alabama and southwest Georgia through Wednesday, so some additional modifications are certainly possible depending upon how much rain actually falls. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 67 69 44 67 37 / 80 90 20 0 0 Panama City 66 69 45 64 44 / 70 80 10 0 0 Dothan 62 65 40 63 41 / 90 70 10 0 0 Albany 62 69 40 64 38 / 90 80 10 0 0 Valdosta 65 69 46 65 38 / 60 90 20 0 0 Cross City 64 74 48 67 39 / 30 80 30 0 0 Apalachicola 67 71 46 63 43 / 60 90 20 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FLASH FLOOD WATCH through Wednesday morning for Central Walton- Holmes-Inland Walton-Jackson-Washington. GA...FLASH FLOOD WATCH through Wednesday morning for Baker-Ben Hill- Calhoun-Clay-Dougherty-Early-Irwin-Lee-Miller-Quitman- Randolph-Seminole-Terrell-Tift-Turner-Worth. AL...FLASH FLOOD WATCH through Wednesday morning for Coffee-Dale- Geneva-Henry-Houston. GM...None. && $$ NEAR TERM/AVIATION...Lamers SHORT TERM/MARINE...Barry FIRE WEATHER/HYDROLOGY...DVD LONG TERM...Barry
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
307 PM EST TUE FEB 12 2013 .SHORT TERM... SFC RIDGING INVOF OF OH RVR WILL BREAK DOWN INADV OF SW CLIPPER DROPPING OUT OF SWRN CANADA WED AFTN. HWVR NO SENSIBLE WX OF CONSEQUENCE XPCD WITHIN THIS EVOLUTION THROUGH THIS PD. MIXING/EROSION OF SC CLD DECK ONGOING THIS AFTN W/PARTIAL SUNSHINE NOW ACRS MUCH OF ERN HALF CWA BUT WRN FLANK EXTENDING BACK INTO NE IL HOLDING TOUGH AND MAY POSE A BUST OVERNIGHT WRT MIN TEMPS. ATTM SHRT TERM RUC GIVES A NOD TWD PRIOR EVEN MOS BLEND. OTRWS AT LEAST PARTIAL INSOLATION XPCD AGAIN ON WED W/STGR DIURNAL WITHIN MODEST LL SWRLY FLW. IN FACT MOS MAX TEMP SPLIT ESSENTIALLY EVEN AND REFLECTED IN GRIDDED MAXS. && .LONG TERM... /THURSDAY THROUGH TUESDAY/ ACTIVE PATTERN IN STORE FOR THE LONG TERM PERIOD. ONE MORE DAY OF ABOVE NORMAL TEMPS ON TAP FOR THURSDAY AHEAD OF SHOT OF ARCTIC AIR DROPPING SE ACROSS THE PLAINS. STRONG FORCING ALONG THE FRONT WILL STIR UP AT LEAST A CHC FOR RAIN OR SNOW SHOWERS BUT OVERALL QPF APPEARS MINIMAL AT THIS POINT. POPS STILL HELD IN CHC/SCHC RANGE FOR NOW. GREATER FOCUS THEN TURNS TOWARDS LAKE EFFECT POTENTIAL AS STG NW FLOW SETS UP WITH SFC-850 MB DELTA T`S PUSHING 20 C AND SFC-700 MB DELTA T`S PUSHING UPR 20S. NAM/WRF SHOW A PERIOD OF FAVORABLE COLLOCATION OF DGZ AND TOP OF STRONG OMEGA. INVERSION HGTS BEGIN TO CLIMB...ESPECIALLY DURING THE DAY FRIDAY WHEN SOME ADDITIONAL SYNOPTIC MSTR ARRIVES AND A REINFORCING SHOT OF COLD AIR. HAVE TENDED TO FOCUS GREATEST POPS FRIDAY TO MATCH WITH THE ABOVE SETUP. ACCUMS AT THIS POINT APPEAR TO BE ON THE LIGHTER SIDE BUT WILL NEED TO BE WATCHED IN COMING FORECASTS. WHILE AN OUTLIER...SEVERAL RUNS OF THE GEM NHEM MODEL HAVE BEEN SHOWING PHASING OF N/S STREAM SYSTEMS SOONER THAN LATER WITH A STORM AFFECTING THE GREAT LAKES VS EAST COAST. ECMWF/GFS DO NOT PHASES THE ENERGY UNTIL REACHING EAST COAST SO AT THIS POINT HAVE TO PUT IT ON THE BACK BURNER BUT WILL NEED TO WATCH. LAKE EFFECT WILL LINGER POTENTIALLY THROUGH MUCH OF THE WEEKEND WITH CONTINUED NW FLOW AND 850 MB RIDGING STILL TO THE WEST UNTIL LATE SUNDAY. NEXT SYSTEM TO FOCUS ON WILL BE WHAT LOOKS LIKE A PANHANDLE HOOK COMING TOWARDS THE REGION MONDAY NIGHT INTO TUESDAY. SIGNALS POINT TOWARDS MEASURABLE PRECIP FOR PARTS OF THE AREA BUT EXACT TRACK AND AMOUNT OF COLD AIR REMAIN QUESTIONABLE THIS FAR OUT IN THE FORECAST. HAVE WENT WITH MID-HIGH END CHC POPS WITH MIX OF RAIN OR SNOW WITH LIKELY REFINEMENT OF FORECAST TO COME OVER THE NEXT SEVERAL DAYS. && .AVIATION... MVFR SC DECK EXTENDING WWD INTO NE IL HOLDING TOUGH THIS AFTN AND NOT MIXING OUT AS ORIGINALLY XPCD. THUS MADE AMENDMENTS TO PUSH BACK CLRG TO LT EVENING BASED ON CONTD EWD EROSION OUT OF WRN IL. OTRWS WX NIL THIS TAF PD W/VFR CONDS XPCD OUTSIDE LT THIS AFTN/EVENING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...T LONG TERM...FISHER AVIATION...T
AREA FORECAST DISCUSSION
NWS GAYLORD MI
418 PM EST TUE FEB 12 2013 .SYNOPSIS... ISSUED AT 415 PM EST TUE FEB 12 2013 WEAK HIGH PRESSURE WILL BUILD INTO THE NORTHERN GREAT LAKES TONIGHT AND WEDNESDAY. THIS PATTERN WILL GENERATE ABOVE NORMAL TEMPERATURES AND OCCASIONAL FLURRIES...ACROSS THE NORTHERN MICHIGAN INTO THURSDAY. HOWEVER...THE NEXT SYSTEM TO INFLUENCE THE GREAT LAKES ARRIVES THURSDAY...BEFORE QUICKLY LIFTING NORTHEAST INTO QUEBEC FRIDAY. THIS SYSTEM WILL GENERATE ANOTHER ROUND OF SNOW ACROSS NORTHERN MICHIGAN THURSDAY...WHILE ALSO USHERING IN MUCH COLDER CONDITIONS FRIDAY AND INTO THE WEEKEND. ACCUMULATING LAKE EFFECT SNOW CAN BE EXPECTED OVER THE WESTERN GREAT LAKES THIS WEEKEND. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 415 PM EST TUE FEB 12 2013 COLD AIR ADVECTION HAS ABOUT MAXED OUT BEHIND YESTERDAY`S DEPARTING STORM...WITH LATEST HIGH RES RUC ANALYSIS PLACING CIRCA -11C H85 TEMPERATURES ACROSS THE NORTH WOODS. DESPITE EXCEEDINGLY LOW INVERSIONS (H85 PER SAME RUC ANALYSIS)...MOISTURE DEPTH EXTENDING TO THE LOW END OF THE FAVORED DGZ CONTINUES TO KICK OFF WIDESPREAD FLURRIES IN FAVORED WEST FLOW LAKE AREAS. ABUNDANT LOW LEVEL MOISTURE ALSO LEADING TO A MAINLY CLOUDY DAY...WITH ANY SUBSTANTIAL CLEARING OF NOTE BACK ACROSS WISCONSIN. THIS CLEARING APPEARS TIED TO DOWNWARD FORCING ON BACKSIDE OF RATHER COMPACT SHORTWAVE PINWHEELING EAST INTO NORTHERN LAKE MICHIGAN. NO SIGNIFICANT CONCERNS THROUGH THE SHORT TERM (WEDNESDAY)...ALTHOUGH LINGERING FLURRIES AND CLOUD TRENDS WILL NEED ADDRESSING. WISCONSIN SHORTWAVE WILL STEADILY AND RAPIDLY PUSH ACROSS THE AREA THIS EVENING...AND LACK OF ANY APPRECIABLE MOISTURE SHOULD PRECLUDE MUCH...IF ANY...LAKE OR SYNOPTIC RESPONSE. H85 TEMPERATURES SLOWLY WARM IN DEVELOPING WEAK SOUTHWEST FLOW WAA REGIME...REACHING THE NEGATIVE SINGLE DIGITS BY MORNING. NAM-WRF BUFFER SOUNDINGS SHOW LOW LEVEL MOISTURE FALLING BELOW -10C ISOTHERM...WHICH COMBINED WITH LOWERING DELTA T/S...WOULD SUPPORT A QUICK DEMISE TO ONGOING FLURRIES. NOT WILLING TO BITE ON THIS JUST YET...AND PREFER TO KEEP FLURRIES IN THE FORECAST...SIMPLY FOLLOWING THE WINDS FOR THERE PLACEMENT (WHICH SUGGESTS THEY SHOULD CONFINE THEMSELVES IN FAVORED SOUTHWEST FLOW AREAS THROUGH THE NIGHT). CLOUD COVER REMAINS A FORMIDABLE CHALLENGE...ESPECIALLY GIVEN WHAT IS OCCURRING BEHIND UPSTREAM WAVE. DO HAVE SOME TREPIDATION GOING TOO AGGRESSIVE WITH CLOUDS OVERNIGHT...ESPECIALLY IN NON-FAVORED LAKE AREAS. SUBTLE WARM ADVECTION AND POST-WAVE DOWNWARD RESPONSE JUST MAY WORK IN TANDEM TO FORCE MUCH MORE CLEARING THAN THIS FORECAST WILL SUGGEST. WILL TREND PARTLY CLOUDY ACROSS EASTERN UPPER AND NORTHEAST LOWER AS A STARTING POINT...WITH KNOWLEDGE THAT COMPLETELY CLOUDY OR CLEAR IS THE MORE LIKELY OUTCOME. TEMPERATURES...OF COURSE...HIGHLY DEPENDENT ON HOW THIS WHOLE CLOUD THING UNFOLDS. MID AND UPPER TEENS MAY BE SEVERAL DEGREES TOO "WARM". WE SHALL SEE. SAME STORY HEADING INTO WEDNESDAY...WITH SOME LINGERING FLURRIES AND MOSTLY TO PARTLY CLOUDY SKIES. LOW LEVEL MODIFICATION CONTINUES...SUGGESTING HIGHS IN THE LOWER AND MIDDLE 30S. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 415 PM EST TUE FEB 12 2013 MAIN FORECAST CONCERNS WILL BE POTENTIAL FOR ACCUMULATING LAKE ENHANCED SNOWS STARTING THURSDAY AND CONTINUING INTO THE WEEKEND. THE LATEST HEMISPHERIC ANALYSIS SHOWS A STABLE 3-WAVE PATTERN WITH LARGE SCALE TROUGHING OVER CENTERED OVER JAMES BAY...EAST ASIA /AROUND 120E/ AND CENTRAL EUROPE. A VERY STRONG ZONAL JET REMAINS OVER EAST ASIA AND THE WESTERN PACIFIC...WITH A SLIT FLOW OVER THE EASTERN PACIFIC EXTENDING INTO THE WEST COAST. THE SPLIT FLOW MERGES TO FORM A FASTER JET THE SOUTHEASTERN U.S. THURSDAY...AN AMPLIFYING PATTERN IS EXPECTED WITH STRONG PACIFIC JET TO BEEF UP THE WEST COAST RIDGE...RESULTING IN INCREASED TROUGHING OVER THE EASTERN TWO THIRDS OF THE CONUS BY THURSDAY. SHORT WAVE ENERGY IS EXPECTED TO ROUND THE TOP OF THE RIDGE ON WEDNESDAY...BEFORE DIVING INTO THE GREAT LAKES BY THURSDAY. AN ASSOCIATED SURFACE RESPONSE/CLIPPER SYSTEM WILL MOVE THOUGH THE GREAT LAKES...BRINGING NORTHERN MICHIGAN THE NEXT CHANCE OF SOME LIGHT SNOW. THE AMOUNT OF MOISTURE THIS SYSTEM HAS TO WORK WITH IS NOT TERRIBLE...WITH MODEL SOUNDINGS SHOWING P-WATS OF AROUND 0.3 TO 0.4 INCHES ACROSS THE CWA. THE DEGREE OF FORCING REMAINS IN SOME QUESTION...WITH TWO DISTINCT AREAS OF ENHANCED PVA EXPECTED TO MOVE THROUGH THE REGION EMBEDDED IN THE SHEARED PIECE OF ENERGY. THE NAM/GFS WANT TO SPIN UP A STRONGER LOW WITH THIS FEATURE...WHILE THE ECMWF/GEM KEEP THE SURFACE LOW MORE BENIGN. PREFER THE LATTER OF THE SOLUTIONS...GIVEN THAT THESE TWO PIECES OF ENERGY DO NOT NECESSARILY PHASE TOGETHER. OVERALL LOOKING LIKE A 1 TO 2..PERHAPS LOCALLY 3 INCH SNOW EVENT. RAPIDLY CHANGING FLOW AND WARMISH AIR ALOFT WITH H85 TEMPS BETWEEN -5 TO -8C LOOK TO KEEP A MAJOR DAMPER OF ANY LAKE ENHANCEMENT. SNOW MAY BE ALSO BE SLOW TO ACCUMULATE ON ROAD SURFACES WITH SURFACE TEMPS AT OR SLIGHTLY ABOVE FREEZING...WITH THE MORE AGGRESSIVE NAM/GFS SUGGESTING HIGHS IN THE MID TO UPPER 30S FOR THURSDAY. THIS WOULD HAVE RAIN/SNOW MIX IMPLICATIONS FOR THE LOWER ELEVATIONS OF THE CWA...BUT PREFER THE MORE COOLER...LESS AMPLIFIED SOLUTIONS FOR NOW. THURSDAY NIGHT AND FRIDAY...FORCING BEGINS TO PUSH EAST OF THE AREA BY LATE THURSDAY AFTERNOON WITH STRONG COLD AIR ADVECTION ENSUING ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THIS WILL RAMP UP THE LAKE EFFECT SNOW MACHINE DURING THIS TIMEFRAME. MODELS ARE NOT IN THE BEST AGREEMENT WITH THE NAM/GFS MORE NORTHWESTERLY THAN THE NNW FLOW DEPICTED BY THE ECMWF. MODEST INVERSION HEIGHTS AND DEEPEST MOISTURE MOVING OUT SHOULD KEEP MAJOR LAKE SNOW ACCUMULATIONS IN CHECK...HOWEVER SEVERAL INCHES OF ACCUMULATION LOOK LIKELY FOR THE NW/NNW FAVORED SNOW BELTS THROUGH FRIDAY. H85 TEMPS FALL TO -15 TO -18C DURING THE DAY FRIDAY...WITH MODEL CONSENSUS SHOWING HIGHS STRUGGLING TO MAKE IT OUT OF THE TEENS. FRIDAY NIGHT THROUGH TUESDAY...CHILLY CONDITIONS ENSUE AS DEEP TROUGH SETTLES INTO THE GREAT LAKES WITH MODEL CONSENSUS SHOWING H85 TEMPS IN THE -18 TO -22 RANGE ACROSS THE GREAT LAKES INTO THE DAY ON SATURDAY. CERTAINLY PLENTY OF INSTABILITY TO KEEP THE LAKE EFFECT SNOW MACHINE GOING...WITH POCKETS OF DEEPER H85-H7 MOISTURE ASSOCIATED WITH EMBEDDED SHORTWAVES ROUNDING THE LONGER WAVE TROUGH AND CONTINUED NORTHWEST TO NORTH NORTHWEST FLOW. AT THE LEAST...SEVERAL INCHES OF ACCUMULATION LOOK LIKELY IN THE NW TO NNW FAVORED SNOW BELTS WITH THIS PATTERN. LOOKING AT SOME OF COOP SNOWFALL GUIDANCE FROM THE CIPS ANALOGS FOR THE 72 HOUR PERIOD CENTERED ON 00Z/17 SHOWS HEAVY ACCUMULATIONS FOR 3 OF THE TO 5 ANALOGS. STILL PLENTY OF DETAILS TO WORK OUT BETWEEN NOW AND THIS WEEKEND...WITH ICE COVER OVER NORTHERN LAKE MICHIGAN AND MODEST INVERSION HEIGHTS SERVING AS MITIGATING FACTORS FOR HEAVY ACCUMULATIONS. STILL COULD SEE THE POSSIBILITY OF SOME HEADLINES FOR THE FRI/SAT TIMEFRAME...AND WILL MAINTAIN THE THREAT FOR ACCUMULATING LAKE SNOWS IN THE HWO. SUNDAY THROUGH MONDAY...PROGRESSIVE PATTERN CONTINUES WITH DEEP TROUGH KICKING OFF TO THE NORTHEAST AND HEIGHTS MODIFYING SUBSTANTIALLY AS UPSTREAM RIDGING BUILDS INTO THE GREAT LAKES. 1000-850 MEAN FLOW IS PROGGED TO BACK TO THE SOUTHWEST WITH H85 TEMPS MODIFYING ENOUGH TO END THE LES THREAT...ALTHOUGH THERE MAY BE SOME LINGER -SHSN FOR SW FAVORED FLOW AREAS INITIALLY SUNDAY MORNING. ANOTHER CLIPPER SYSTEM LOOKS TO TRAVERSE THE AREA SUNDAY NIGHT INTO MONDAY...HOWEVER THE BETTER MOISTURE AND FORCING LOOK TO REMAIN OVER THE NORTHERN PORTION OF THE CWA ATTM. MONDAY NIGHT INTO TUESDAY...NEXT TROUGH BUILDS INTO THE GREAT LAKES WITH GFS/ECMWF DEPICTING A STORM SYSTEM DEVELOPING IN THE SOUTHERN PLAINS AND MOVING UP THROUGH THE OHIO VALLEY INTO THE GREAT LAKES. NOT A LOT OF CONFIDENCE OF COURSE THIS FAR OUT...ESPECIALLY WHEN LOOKING AT SOME OF THE ENSEMBLE GUIDANCE ON THE UPPER AIR PATTERN...BUT SOME SIGNALS ARE THERE OF SAID SYSTEM WHEN LOOKING AT THE REANALYSIS BASED ON THE TOP GFS/CAN ENS TOP ANALOGS. SOMETHING THAT WILL CERTAINLY NEED TO BE MONITORED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1237 PM EST TUE FEB 12 2013 ABUNDANT MVFR PRODUCING STCU DECK CONTINUES TO ROTATE OFF LAKE MICHIGAN...OVERSPREADING ALL TAF SITES. CLOUD FIELD CONTINUES TO PRODUCE WIDESPREAD FLURRIES ACROSS WESTERN TAF SITES. FLOW VEERS SLOWLY AROUND TO SOUTHWEST...WITH LIGHT SOUTHWEST WINDS CONTINUING TONIGHT INTO WEDNESDAY MORNING. THIS SHOULD TARGET BEST FLURRY ACTIVITY ACROSS KPLN TONIGHT AND WEDNESDAY MORNING. OTHERWISE...STCU MVFR DECK SHOULD CONTINUE AS MOISTURE REMAINS TRAPPED BELOW STRONG INVERSION. SOME POTENTIAL FOR CLEARING OUTSIDE OF KPLN OVERNIGHT...BUT NOT CONFIDENT ENOUGH TO GO THAT DIRECTION JUST YET. && .MARINE... ISSUED AT 415 PM EST TUE FEB 12 2013 MARINE...VEERING WINDS TO SOUTHWEST REMAIN SOMEWHAT GUSTY HEADING INTO THIS EVENING. MAY EVEN SEE SOME SCA PRODUCING GUSTS ALONG THE NORTHWEST LOWER LAKE MICHIGAN COAST...ALTHOUGH DURATION DOES NOT SUPPORT A SPECIFIC SCA HEADLINE. SOUTHWEST AND SUB-ADVISORY WINDS TO CONTINUE THROUGH THURSDAY MORNING. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ SYNOPSIS...SR SHORT TERM...MB LONG TERM...NS AVIATION...MB MARINE...MB