Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 01/14/12


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1100 AM MST THU JAN 12 2012 .UPDATE...FEW CHANGES NEEDED FOR THE SHORT TERM. ANY BLOWING SNOW THAT OCCURS SHOULD BE VERY LOCALIZED AND CAN BE HANDLED BY NOWCASTS. SO WILL NOT EXTEND THE PATCHY BLOWING SNOW GRID INTO THIS AFTERNOON. MODELS CONTINUE TO SHOW A WEAKENING GRADIENT ACROSS THE PLAINS THIS EVENING...WOULD EXPECT A DECREASE IN WINDS AS A RESULT. WATER VAPOR LOOPS SHOW SOME SORT OF A WEAK WAVE MOVING INTO WESTERN WYOMING...WITH MAINLY HIGH LEVEL MOISTURE. MODELS DON`T SEEM TO PICK UP THIS FEATURE...WILL NEED TO MONITOR FOR ANY TYPE OF WIND INCREASE AS THIS FEATURE MOVES AWAY FROM THE AREA. && .AVIATION...DELAYED THE SHIFT TO NORTHWEST AT AREA AIRPORTS TIL 20Z...AS SHOWN BY RUC. NAM AND HRRR KEEP THE SOUTHWEST WINDS PREVAILING. NOT SURE ABOUT THE GFS AND THE WEAK EASTERLIES. WILL MONITOR FOR ANY DEVELOPMENT OF A DENVER CYCLONE. OTHERWISE...TAF TRENDS SEEM REASONABLE. && .PREV DISCUSSION... /ISSUED 251 AM MST THU JAN 12 2012/ SHORT TERM...NW FLOW ALOFT WILL BE OVER THE AREA TODAY. GUSTY WINDS WILL BE POSSIBLE IN THE MTNS AND ALONG THE FOOTHILLS THRU THE MORNING HOURS WITH A FEW AREAS OF BLOWING SNOW. OVER NERN CO GUSTY NWLY WINDS WILL ALSO OCCUR WHICH WILL LINGER THROUGH THE AFTN HOURS BUT SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. AS FOR HIGHS WILL KEEP READINGS MAINLY IN THE 35 TO 40 DEGREE RANGE OVER NERN CO. FOR TONIGHT A WEAK UPPER LEVEL TROUGH IN NW FLOW WILL MOVE ACROSS THE AREA HOWEVER CROSS-SECTIONS SHOW MOISTURE CONFINED TO THE MID AND UPPER LEVELS. THUS WILL SEE AN INCREASE IN CLOUDS WITH ONLY A FEW FLURRIES OVER THE HIGHER MTN PEAKS. LATE TONIGHT AS SUBSIDENCE DEVELOPS BEHIND PASSAGE OF WEAK UPPER LEVEL TROUGH WINDS MAY INCREASE IN AND NR THE FOOTHILLS HOWEVER SPEEDS SHOULD REMAIN BLO WARNING CRITERIA. LONG TERM...MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE FORECAST AREA ON FRIDAY...WITH AN UPPER RIDGE TO OUR WEST. DECREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR FRIDAY NIGHT THROUGH SATURDAY. BY SATURDAY NIGHT...WEAK ZONAL FLOW ALOFT IS PROGGED. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK DOWNWARD MOTION PROGGED FOR THE CWA THROUGH SATURDAY NIGHT. THE BOUNDARY LAYER FLOW LOOKS TO BE A MIX OF THE NORMAL DIURNAL PATTERN COUPLED WITH DOWNSLOPING WITH TROUGHING EAST OF THE MOUNTAINS THROUGH THE PERIOD. FOR MOISTURE...THERE IS A BIT IN THE MID AND UPPER LEVELS THROUGH THE PERIOD. THE IS NO MEASURABLE PRECIPITATION ON THE QPF FIELDS THROUGH THE PERIOD. NO POPS. CROSS SECTIONS SHOW A BIT OF MOUNTAINS WAVE SET UP FRIDAY AFTERNOON AND NIGHT. HOWEVER...IT IS NOT SIGNIFICANT. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 2-5 C WARMER THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 2-4 C. WILL UNDERCUT MOS GUIDANCE NUMBERS...ESPECIALLY IN THE AREAS WHERE THERE IS SNOW ON THE GROUND. FOR THE LATER DAYS...SUNDAY THROUGH WEDNESDAY...ZONAL FLOW GIVES WAY TO SOUTHWESTERLY FLOW ALOFT ON SUNDAY AND SUNDAY NIGHT. THE ECMWF AND GFS BOTH SHOW A BROAD UPPER TROUGH TO MOVE INTO COLORADO LATER MONDAY AND MONDAY NIGHT. BOTH HAVE A COLD FRONT AND UPSLOPE FOR THE PLAINS AND FOOTHILLS MONDAY AFTERNOON AND EVENING. IT IS A QUICK SHOT. FOR TUESDAY AND WEDNESDAY... NORTHWESTERLY FLOW ALOFT IS PROGGED...AND THERE IS MOISTURE WITH IT. PERHAPS OUR MOUNTAINS WILL SEE SOME SNOW. WILL LEAVE THE EXTENDED GFE GRIDS PRETTY MUCH ALONE. AVIATION...VFR THRU TONIGHT. WILL KEEP WINDS SSW THRU THE MORNING HOURS AROUND 10 KTS. BY AFTN HRRR KEEPS WINDS MAINLY WSW WHILE THE RUC HAS THEM SHIFTING TO MORE OF A WNW DIRECTION WITH SPEEDS AROUND 10 KTS. FOR NOW WILL TREND TOWARDS A WNW DIRECTON. BY EARLY EVENING WINDS WILL GRADUALLY BECOME MORE WSW. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RJK AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
251 AM MST THU JAN 12 2012 .SHORT TERM...NW FLOW ALOFT WILL BE OVER THE AREA TODAY. GUSTY WINDS WILL BE POSSIBLE IN THE MTNS AND ALONG THE FOOTHILLS THRU THE MORNING HOURS WITH A FEW AREAS OF BLOWING SNOW. OVER NERN CO GUSTY NWLY WINDS WILL ALSO OCCUR WHICH WILL LINGER THROUGH THE AFTN HOURS BUT SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. AS FOR HIGHS WILL KEEP READINGS MAINLY IN THE 35 TO 40 DEGREE RANGE OVER NERN CO. FOR TONIGHT A WEAK UPPER LEVEL TROUGH IN NW FLOW WILL MOVE ACROSS THE AREA HOWEVER CROSS-SECTIONS SHOW MOISTURE CONFINED TO THE MID AND UPPER LEVELS. THUS WILL SEE AN INCREASE IN CLOUDS WITH ONLY A FEW FLURRIES OVER THE HIGHER MTN PEAKS. LATE TONIGHT AS SUBSIDENCE DEVELOPS BEHIND PASSAGE OF WEAK UPPER LEVEL TROUGH WINDS MAY INCREASE IN AND NR THE FOOTHILLS HOWEVER SPEEDS SHOULD REMAIN BLO WARNING CRITERIA. .LONG TERM...MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE FORECAST AREA ON FRIDAY...WITH AN UPPER RIDGE TO OUR WEST. DECREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR FRIDAY NIGHT THROUGH SATURDAY. BY SATURDAY NIGHT...WEAK ZONAL FLOW ALOFT IS PROGGED. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK DOWNWARD MOTION PROGGED FOR THE CWA THROUGH SATURDAY NIGHT. THE BOUNDARY LAYER FLOW LOOKS TO BE A MIX OF THE NORMAL DIURNAL PATTERN COUPLED WITH DOWNSLOPING WITH TROUGHING EAST OF THE MOUNTAINS THROUGH THE PERIOD. FOR MOISTURE...THERE IS A BIT IN THE MID AND UPPER LEVELS THROUGH THE PERIOD. THE IS NO MEASURABLE PRECIPITATION ON THE QPF FIELDS THROUGH THE PERIOD. NO POPS. CROSS SECTIONS SHOW A BIT OF MOUNTAINS WAVE SET UP FRIDAY AFTERNOON AND NIGHT. HOWEVER...IT IS NOT SIGNIFICANT. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 2-5 C WARMER THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 2-4 C. WILL UNDERCUT MOS GUIDANCE NUMBERS...ESPECIALLY IN THE AREAS WHERE THERE IS SNOW ON THE GROUND. FOR THE LATER DAYS...SUNDAY THROUGH WEDNESDAY...ZONAL FLOW GIVES WAY TO SOUTHWESTERLY FLOW ALOFT ON SUNDAY AND SUNDAY NIGHT. THE ECMWF AND GFS BOTH SHOW A BROAD UPPER TROUGH TO MOVE INTO COLORADO LATER MONDAY AND MONDAY NIGHT. BOTH HAVE A COLD FRONT AND UPSLOPE FOR THE PLAINS AND FOOTHILLS MONDAY AFTERNOON AND EVENING. IT IS A QUICK SHOT. FOR TUESDAY AND WEDNESDAY... NORTHWESTERLY FLOW ALOFT IS PROGGED...AND THERE IS MOISTURE WITH IT. PERHAPS OUR MOUNTAINS WILL SEE SOME SNOW. WILL LEAVE THE EXTENDED GFE GRIDS PRETTY MUCH ALONE. && .AVIATION...VFR THRU TONIGHT. WILL KEEP WINDS SSW THRU THE MORNING HOURS AROUND 10 KTS. BY AFTN HRRR KEEPS WINDS MAINLY WSW WHILE THE RUC HAS THEM SHIFTING TO MORE OF A WNW DIRECTION WITH SPEEDS AROUND 10 KTS. FOR NOW WILL TREND TOWARDS A WNW DIRECTON. BY EARLY EVENING WINDS WILL GRADUALLY BECOME MORE WSW. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ RPK/RJK
AREA FORECAST DISCUSSION
NWS ALBANY NY
950 PM EST FRI JAN 13 2012 .SYNOPSIS... LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... WINTER STORM WARNING AND SOME OF THE WINTER WEATHER ADVISORIES HAVE BEEN DROPPED. SNOW HAS DIMINISHED GREATLY ACROSS THE REGION AS THE INVERSIONS AND MOISTURE LAYER HAVE BECOME MORE SHALLOW. LAKE EFFECT BAND NOSING INTO HERKIMER AND HAMILTON COUNTIES RELATIVELY STABLE AND SHOULD CONTINUE TO PRODUCE LIGHT TO MODERATE SNOW...LOCALLY HEAVY SNOW THROUGH THE EARLY MORNING HOURS. HAVE DROPPED ALL HEADLINES EXCEPT FOR THE WINTER WEATHER ADVISORY IN THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...WHERE IT HAS BEEN EXTENDED UNTIL 6 AM. THE LAKE EFFCT BAND MAY BREAK UP BEFORE THEN BUT IT CAN BE CANCELLED EARLY IF NECESSARY. THERE MAY BE ONLY AN INCH OR TWO ADDITIONAL ACCUMULATION IN THOSE AREAS...WITH STORM TOTALS OF 4 TO UP TO AROUND 8 INCHES LOCALLY. WITH THE CLOUD COVER AND THE WINDS STAYING UP...TEMPERATURES ARE NOT FALLING MUCH...BUT UPSTREAM TEMPERATURES SHOULD ADVECT INTO OUR REGION BY DAYBREAK. SO...LOW TEMPERATURES SEEM TO BE IN THE BALLPARK. PREV AFD BELOW... WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED. SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS. SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE CHANGES LATER THIS EVENING. PREV AFD BELOW... AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA COUNTIES TO 4-8" TOO. PREVIOUS NEAR TERM... AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES. THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK VALLEY. THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z- 03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS. THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE. LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE WILL HAVE TO MONITOR IF THIS MATERIALIZES. IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35 KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO 35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS AROUND 35 MPH. A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH. LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN MTNS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST. THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO NORTH AND WEST OF THE CAPITAL REGION. SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN THE SRN DACKS. SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS NORTH. && .LONG TERM /MONDAY THROUGH FRIDAY/... A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY. THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A WINTRY MIX...DEPENDING ON ELEVATION. THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS. NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING. WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT. SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST WITH CLOUD COVER DECREASING THROUGHOUT THE DAY. WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25 KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING. OUTLOOK... SAT-MON...VFR...NO SIG WX. MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX. WED...VFR...SLGT CHC -SHSN. && .HYDROLOGY... NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL BY TUESDAY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST SATURDAY FOR NYZ032-033- 038. MA...NONE. VT...NONE. && $$ SYNOPSIS...NAS NEAR TERM...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
713 PM EST FRI JAN 13 2012 .SYNOPSIS... LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED. SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS. SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE CHANGES LATER THIS EVENING. PREV AFD BELOW... AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA COUNTIES TO 4-8" TOO. PREVIOUS NEAR TERM... AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES. THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK VALLEY. THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z- 03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS. THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE. LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE WILL HAVE TO MONITOR IF THIS MATERIALIZES. IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35 KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO 35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS AROUND 35 MPH. A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH. LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN MTNS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST. THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO NORTH AND WEST OF THE CAPITAL REGION. SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN THE SRN DACKS. SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS NORTH. && .LONG TERM /MONDAY THROUGH FRIDAY/... A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY. THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A WINTRY MIX...DEPENDING ON ELEVATION. THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS. NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING. WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT. SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST WITH CLOUD COVER DECREASING THROUGHOUT THE DAY. WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25 KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING. OUTLOOK... SAT-MON...VFR...NO SIG WX. MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX. WED...VFR...SLGT CHC -SHSN. && .HYDROLOGY... NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL BY TUESDAY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032- 033-038-042-054-061. MA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ025. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MAZ001. VT...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VTZ013-014. && $$ SYNOPSIS...NAS NEAR TERM...NAS AVIATION...KGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
702 PM EST FRI JAN 13 2012 .SYNOPSIS... LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA COUNTIES TO 4-8" TOO. PREVIOUS NEAR TERM... AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES. THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK VALLEY. THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z- 03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS. THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE. LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE WILL HAVE TO MONITOR IF THIS MATERIALIZES. IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35 KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO 35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS AROUND 35 MPH. A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH. LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN MTNS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST. THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO NORTH AND WEST OF THE CAPITAL REGION. SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN THE SRN DACKS. SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS NORTH. && .LONG TERM /MONDAY THROUGH FRIDAY/... A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY. THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A WINTRY MIX...DEPENDING ON ELEVATION. THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS. NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING. WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT. SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST WITH CLOUD COVER DECREASING THROUGHOUT THE DAY. WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25 KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING. OUTLOOK... SAT-MON...VFR...NO SIG WX. MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX. WED...VFR...SLGT CHC -SHSN. && .HYDROLOGY... NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL BY TUESDAY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032- 033-038-042-054-061. MA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ025. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MAZ001. VT...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VTZ013-014. && $$ SYNOPSIS...WASULA NEAR TERM...WASULA SHORT TERM...WASULA LONG TERM...KGM AVIATION...KGM HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
105 PM EST THU JAN 12 2012 .SYNOPSIS... A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK. ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA. 12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER TO THE COASTAL FLOOD SECTION BELOW. AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE. DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY OR SLIGHTLY FALL FROM THEIR CURRENT READINGS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS. STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY. WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH PRES BUILDS ACROSS. AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING. DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR WED. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... LOW PRESSURE PASSES JUST SOUTH OF LONG ISLAND THIS AFTERNOON. A POWERFUL COLD FRONT PASSES FRI MRNG. SCATTERED AREAS OF LIGHT RAIN IN THE AREA THIS AFTERNOON. TEMPO MVFR VSBYS PSBL WITH -RA AND BR. MODERATE CONFIDENCE REGARDING CEILING FORECAST. CIGS MAY DROP TO IFR AT SOME TERMINALS. WIND FORECAST ALSO MODERATE CONFIDENCE. TREND WILL BE WINDS SHIFTING TO THE N-NW THEN EVENTUALLY W-SW...BUT TIMING MAY NEED TO BE AMENDED. SUSTAINED WIND SPEEDS AND GUSTS DIMINISH...BUT AMENDMENTS ALSO POSSIBLE FOR TIMING. LOW CIGS EXPECTED TO CONTINUE TONIGHT...WITH A SMALL CHANCE THAT SOME TERMINALS MAY LIFT TO VFR THIS EVENING. COLD FRONT APPROACHES TOWARDS MORNING. MODERATE CONFIDENCE OF RAINFALL...WITH POSSIBILITY THAT SOME TERMINALS SEE EITHER BRIEF OR NO RAIN. CIGS COULD ALTERNATE BETWEEN MVFR AND IFR. ALSO CHANCE OF SNOW MIXED WITH RAIN AT KSWF. HIGH CONFIDENCE OF GUSTY WINDS FRIDAY...BEGINNING IN THE MORNING. COULD SEE GUSTS AS HIGH AS 40KT AT TIMES. HIGH CONFIDENCE OF WIND DIRECTION LEFT OF 310 AT NYC TERMINALS. VFR BY LATE MORNING. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. GUSTS MAY DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS PSBL. KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN WSW. SW FLOW MAY DEVELOP HERE EARLIER THAN AT KLGA/KEWR. GUSTS MAY DIMINISH EARLIER THAN FORECAST. IFR CIGS AND MVFR VSBYS PSBL AT TIMES. KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN WSW. SW FLOW MAY DEVELOP HERE EARLIER THAN AT KLGA/KEWR. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OCCASIONAL IFR CIGS/VSBYS POSSIBLE. KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. SW FLOW MAY DEVELOP HERE EARLIER THAN AT KLGA/KEWR. CIGS/VSBYS MAY FLUCTUATE BETWEEN MVFR AND IFR AT TIMES. KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. CIGS MAY FLUCTUATE BETWEEN MVFR AND IFR AT TIMES. CHANCE OF MVFR VSBYS. KISP FCSTER COMMENTS: CIGS MAY VARY BETWEEN IFR AND MVFR. MVFR VSBYS MAY LINGER LONGER THAN FORECAST. AMENDMENTS POSSIBLE TO REFINE TIMING WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN WSW. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY... FRI AFTERNOON...VFR. WIND GUSTS AROUND 35KT...POSSIBLY EXCEEDING 40 KT AT TIMES. SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS. SUN-MON...VFR. TUE...SUB-VFR PSBL. && .MARINE... GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW LEVEL JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE AREA WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF STRONG GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN 5 AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS THE EASTERN WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT LEVELS THIS AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL BELOW SMALL CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD FRONT. SEAS HOWEVER WILL REMAIN AT SCA LEVELS. SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16 FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND. THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE ABOUT A 12-HR LULL BETWEEN THE TWO. GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER AIR MOVES IN FROM THE NORTH. && .HYDROLOGY... RAINFALL AMOUNTS RANGED FROM 1 TO 1.5 INCHES FROM THIS EVENT. NO FLOODING PROBLEMS ARE ANTICIPATED. AN ADDITIONAL TENTH TO TWO TENTHS OF RAINFALL IS POSSIBLE LATE TONIGHT INTO FRIDAY MORNING. DRY WEATHER RETURNS LATE FRIDAY THROUGH THE WEEKEND. && .TIDES/COASTAL FLOODING... THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS. THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG... PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3 FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT... A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR. THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR FLOODING ACROSS THESE AREAS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR CTZ009>012. NY...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ078-079-081. COASTAL FLOOD WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NYZ071- 073-176-177. NJ...NONE. MARINE...GALE WARNING FROM 6 AM FRIDAY TO MIDNIGHT EST FRIDAY NIGHT FOR ANZ330-335-338-340-345-350-353-355. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330- 335-340. SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ350-353-355. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...KCS MARINE... HYDROLOGY... TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1241 PM EST THU JAN 12 2012 .SYNOPSIS... LOW PRESSURE SOUTH OF LONG ISLAND WILL DRIFT TO OUR EAST THIS AFTERNOON. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1100 AM...DROPPED WEATHER ADVISORIES FOR OUR HUDSON VALLEY FROM THE CAPITAL DISTRICT SOUTHWARD....AS WELL AS WESTERN ULSTER COUNTY AND NORTHERN LITCHFIELD COUNTY. SOME OF THESE AREAS HAVE BEEN REPORTING A MIX...BUT WITH TEMPERATURES ABOVE FREEZING...NO MORE ACCUMULATIONS ARE EXPECTED. WE KEPT THE WINTER WEATHER ADVISORY UP FOR MOST OF THE THE HIGHER TERRAIN SURROUNDING THE CAPITAL DISTRICT AS TEMPERATURES WERE STILL IN SOME CASES...BELOW FREEZING. THE ADVISORY IS MAINLY FOR POCKETS OF FREEZING. WITH THE EXCEPTION OF THE ADIRONDACKS...ANY ADDITIONAL ACCUMULATIONS IN THESE AREA OF SNOW WOULD ONLY 1-2 INCHES. THE ADIRONDACKS COULD SEE UP TO 3 INCHES ADDITIONAL SNOWFALL...BUT MOST AREAS EVEN THERE WILL CLOSE TO AN INCH. TEMPERATURES WILL SLOWLY RISE TO AT OR ABOVE FREEZING HIGHER TERRAIN AND AREA NORTH OF ALBANY...WITH VALLEY AREAS 35 TO 40. SOME AREAS PRIMED TO DOWNSLOPING WINDS OFF THE HIGHER TERRAIN COULD REACH INTO THE LOWER 40S. **********PREVIOUS NEAR TERM DISCUSSION**************** AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING. ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000 FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING SNOWFLAKES TO COOL THE COLUMN. UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS WELL). ********PREVIOUS NEAR TERM FORECAST******** AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR THE SOUTHERN ADIRONDACKS. AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... LOW CONFIDENCE FORECAST FOR MAINLY THE TONIGHT PERIOD. THE STORM THAT IMPACTED THE TAFS EARLIER...WAS PULLING AWAY TO THE EAST OF LONG ISLAND. IN ITS WAKE...LOTS OF MVFR CLOUDS WILL PERSIST. THEN...ANOTHER DISTURBANCE AND COLD FRONT WILL APPROACH THE TAF SITES ON FRIDAY...BRINGING MUCH COLDER AIR BEHIND IT. THE BULK OF THE PRECIPITATION ASSOCIATED WITH THE STORM...IS FINISHED. THERE MIGHT BE SOME OCCASIONAL DRIZZLE BUT THAT SHOULD BE MAINLY IT THROUGH THIS EVENING. WILL CONTINUE WITH THE VCSH TO REFLECT THE POSSIBILITY OF SHOWERS THROUGH THE EVENING. SHOWERS WILL BREAK OUT LATER OVERNIGHT INTO FRIDAY...MIXING WITH SNOW BY MIDDAY AT ALL TAF SITES. THE PROBLEM TONIGHT IS RIGHT NOW WE ARE ASSUMING THE CLOUDS WILL HOLD. IF THEY DO...ALL THE TAFS WILL LIKELY HAVE MVFR CONDITIONS (MAINLY CIG...AOB 2000 FEET). HOWEVER...IF THE CLOUDS WERE TO THIN OR EVEN CLEAR OUT (WHICH WE LEAN AGAINST BUT CERTAINLY POSSIBLE)...SOME IFR FOG IS POSSIBLE...ESPECIALLY AT KGFL. THE WIND ALOFT LOOKS REMAIN 30KTS OR HIGHER (WELL OFF THE DECK) WHICH SHOULD HELP MITIGATE THE FORMATION OF IFR FOG. FOR NOW...NO MENTION OF IFR UNTIL THE SHOWERS BEGIN TURNING TO SNOW...WHICH LOOKS TO BE AROUND 15Z FRIDAY. HOWEVER...IF THE FRONT MOVES IN FASTER...THE CHANGEOVER COULD EVEN BE A LITTLE QUICKER. THE NORTHERLY WIND 5-10 KTS WILL TURN SOUTHERLY LATER TOWARD EVENING. THEY WILL TEND TO INCREASE A LITTLE OVERNIGHT...ESPECIALLY AT KALB. THEN...THEY WILL SHIFT INTO THE WEST OR SOUTHWEST...AND BECOME GUSTY AT KALB. NOT SHOWN IN THE TAFS IS THAT THE WIND LOOKS TO BECOME STRONG AT ALL THE TAF SITES BY LATER FRIDAY AFTERNOON...POSSIBLY GUSTING TO OVER 30KTS...ESPECIALLY AT KALB. THERE MIGHT ALSO BE INTENSE SNOW SQUALLS BRIEFLY REDUCING VISIBILITY TO WELL UNDER A MILE. BEST TO CHECK IN WITH THE FORECAST/DISCUSSION FOR LATER UPDATES. OUTLOOK... FRI NT...MAINLY VFR...WINDY. CHC MVFR -SHSN. SUN-MON...VFR...NO SIG WX. TUE...VFR...CHC MVFR -RASN. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042-043-082. MA...NONE. VT...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...HWJIV/11/NAS NEAR TERM...HWJIV/11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...HWJIV HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
1105 AM EST THU JAN 12 2012 .SYNOPSIS... LOW PRESSURE SOUTH OF LONG ISLAND WILL DRIFT TO OUR EAST THIS AFTERNOON. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1100 AM...DROPPED WEATHER ADVISORIES FOR OUR HUDSON VALLEY FROM THE CAPITAL DISTRICT SOUTHWARD....AS WELL AS WESTERN ULSTER COUNTY AND NORTHERN LITCHFIELD COUNTY. SOME OF THESE AREAS HAVE BEEN REPORTING A MIX...BUT WITH TEMPERATURES ABOVE FREEZING...NO MORE ACCUMULATIONS ARE EXPECTED. WE KEPT THE WINTER WEATHER ADVISORY UP FOR MOST OF THE THE HIGHER TERRAIN SURROUNDING THE CAPITAL DISTRICT AS TEMPERATURES WERE STILL IN SOME CASES...BELOW FREEZING. THE ADVISORY IS MAINLY FOR POCKETS OF FREEZING. WITH THE EXCEPTION OF THE ADIRONDACKS...ANY ADDITIONAL ACCUMULATIONS IN THESE AREA OF SNOW WOULD ONLY 1-2 INCHES. THE ADIRONDACKS COULD SEE UP TO 3 INCHES ADDITIONAL SNOWFALL...BUT MOST AREAS EVEN THERE WILL CLOSE TO AN INCH. TEMPERATURES WILL SLOWLY RISE TO AT OR ABOVE FREEZING HIGHER TERRAIN AND AREA NORTH OF ALBANY...WITH VALLEY AREAS 35 TO 40. SOME AREAS PRIMED TO DOWNSLOPING WINDS OFF THE HIGHER TERRAIN COULD REACH INTO THE LOWER 40S. **********PREVIOUS NEAR TERM DISCUSSION**************** AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING. ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000 FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING SNOWFLAKES TO COOL THE COLUMN. UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS WELL). ********PREVIOUS NEAR TERM FORECAST******** AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR THE SOUTHERN ADIRONDACKS. AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING TOWARD KPOU. REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR 20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT (NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH. ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL. IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM. OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND 40/45KTS THROUGH MUCH OF THE MORNING. EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH TIME. ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS. OUTLOOK... FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECOMING WINDY. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047-048-051-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...HWJIV/11/NAS NEAR TERM...HWJIV/11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...HWJIV HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1107 AM EST THU JAN 12 2012 .SYNOPSIS... A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK. ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA. 12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER TO THE COASTAL FLOOD SECTION BELOW. AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE. DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY OR SLIGHTLY FALL FROM THEIR CURRENT READINGS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS. STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY. WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH PRES BUILDS ACROSS. AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING. DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR WED. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... LOW PRESSURE PASSES OVER THE METRO LATE THIS MORNING AND EARLY AFTERNOON...THEN NE OF THE REGION THIS AFTERNOON. A POWERFUL COLD FRONT PASSES FRI MRNG. AS OF 1450Z...RAIN HAS MOVED NORTH AND EAST OF THE NYC TERMINALS AND WILL CONTINUE MOVING TO THE NORTHEAST. MODERATE CONFIDENCE ON CIGS/VSBYS WITH LOW STRATUS AND FOG CONTINUING OVER THE REGION. MOST SIGNIFICANT CHANGE TO 15Z TAF UPDATE RELATES TO NYC TERMINAL WINDS. LOOKS LIKE LOW PRESSURE WILL TRACK JUST EAST OF NYC...CAUSING WINDS TO SHIFT N-NW LATE MORNING THROUGH EARLY AFTERNOON BEFORE SETTLING TO THE SW. MODERATE CONFIDENCE REGARDING GUSTS. GUSTS MAY DIMINISH EARLIER THAN FORECAST OVER THE NYC METROS. LATEST DATA SUGGESTS MVFR CIGS LAST THRU THE DAY AND OVERNIGHT. BAND OF RAIN LATE TONIGHT AHEAD OF THE COLD FRONT. THIS COULD MIX WITH AND CHANGE TO SNOW...ESPECIALLY KSWF. STRONG WINDS DEVELOP BEHIND THE COLD FRONT FRI MRNG. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS PSBL. KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. IFR CIGS PSBL AT TIMES. KLGA FCSTER COMMENTS: CIGS/VSBYS MAY IMPROVE TO MVFR EARLIER THAN FORECAST. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OCCASIONAL IFR CIGS PSBL. KHPN FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. KISP FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... FRI...CHANCE FOR IFR OR MVFR IN SNOW/RAIN SHOWERS. W-NW WINDS WITH GUSTS ABOVE 40 KT. SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS. SUN...VFR. GUSTY N WINDS LATE. MON...VFR. && .MARINE... GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW LEVEL JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE AREA WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF STRONG GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN 5 AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS THE EASTERN WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT LEVELS THIS AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL BELOW SMALL CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD FRONT. SEAS HOWEVER WILL REMAIN AT SCA LEVELS. SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16 FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND. THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE ABOUT A 12-HR LULL BETWEEN THE TWO. GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER AIR MOVES IN FROM THE NORTH. && .HYDROLOGY... RAINFALL AMOUNTS RANGED FROM 1 TO 1.5 INCHES FROM THIS EVENT. NO FLOODING PROBLEMS ARE ANTICIPATED. AN ADDITIONAL TENTH TO TWO TENTHS OF RAINFALL IS POSSIBLE LATE TONIGHT INTO FRIDAY MORNING. DRY WEATHER RETURNS LATE FRIDAY THROUGH THE WEEKEND. && .TIDES/COASTAL FLOODING... THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS. THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG... PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3 FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT... A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR. THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR FLOODING ACROSS THESE AREAS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR CTZ009>012. NY...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ071-073-078-079-081-176-177. COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR NYZ072-074-075- 178-179. NJ...COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR NJZ006-106-108. MARINE...GALE WARNING UNTIL NOON EST TODAY FOR ANZ330-335-338-340-345- 350-353-355. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...KCS MARINE... HYDROLOGY... TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1104 AM EST THU JAN 12 2012 .SYNOPSIS... A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK. ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA. 12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER TO COASTAL FLOOD SECTION BELOW. AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE. DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY OR SLIGHTLY FALL FROM THEIR CURRENT READINGS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS. STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY. WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH PRES BUILDS ACROSS. AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING. DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR WED. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... LOW PRESSURE PASSES OVER THE METRO LATE THIS MORNING AND EARLY AFTERNOON...THEN NE OF THE REGION THIS AFTERNOON. A POWERFUL COLD FRONT PASSES FRI MRNG. AS OF 1450Z...RAIN HAS MOVED NORTH AND EAST OF THE NYC TERMINALS AND WILL CONTINUE MOVING TO THE NORTHEAST. MODERATE CONFIDENCE ON CIGS/VSBYS WITH LOW STRATUS AND FOG CONTINUING OVER THE REGION. MOST SIGNIFICANT CHANGE TO 15Z TAF UPDATE RELATES TO NYC TERMINAL WINDS. LOOKS LIKE LOW PRESSURE WILL TRACK JUST EAST OF NYC...CAUSING WINDS TO SHIFT N-NW LATE MORNING THROUGH EARLY AFTERNOON BEFORE SETTLING TO THE SW. MODERATE CONFIDENCE REGARDING GUSTS. GUSTS MAY DIMINISH EARLIER THAN FORECAST OVER THE NYC METROS. LATEST DATA SUGGESTS MVFR CIGS LAST THRU THE DAY AND OVERNIGHT. BAND OF RAIN LATE TONIGHT AHEAD OF THE COLD FRONT. THIS COULD MIX WITH AND CHANGE TO SNOW...ESPECIALLY KSWF. STRONG WINDS DEVELOP BEHIND THE COLD FRONT FRI MRNG. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS PSBL. KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. IFR CIGS PSBL AT TIMES. KLGA FCSTER COMMENTS: CIGS/VSBYS MAY IMPROVE TO MVFR EARLIER THAN FORECAST. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OCCASIONAL IFR CIGS PSBL. KHPN FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. KISP FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... FRI...CHANCE FOR IFR OR MVFR IN SNOW/RAIN SHOWERS. W-NW WINDS WITH GUSTS ABOVE 40 KT. SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS. SUN...VFR. GUSTY N WINDS LATE. MON...VFR. && .MARINE... GUSTS UP TO 45 KT POSSIBLE ACROSS EASTERN LI SOUND THROUGH MID MORNING AS THE LOW-LEVEL JET PIVOTS ACROSS THE WATERS. GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW LEVEL JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE AREA WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF STRONG GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN 5 AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS THE EASTERN WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT LEVELS THIS AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL BELOW SMALL CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD FRONT. SEAS HOWEVER WILL REMAIN AT SCA LEVELS. SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16 FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND. THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE ABOUT A 12-HR LULL BETWEEN THE TWO. GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER AIR MOVES IN FROM THE NORTH. && .HYDROLOGY... THREE QUARTERS TO AROUND 1 INCH OF RAINFALL IS EXPECTED THROUGH MIDDAY TODAY. MINOR URBAN AND POOR DRAINAGE FLOODING IS POSSIBLE THIS MORNING. AN ADDITIONAL TENTH TO TWO TENTHS OF RAINFALL IS POSSIBLE LATE TONIGHT INTO FRIDAY MORNING. DRY WEATHER RETURNS LATE FRIDAY THROUGH THE WEEKEND. && .TIDES/COASTAL FLOODING... THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS. THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG... PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3 FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT... A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR. THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR FLOODING ACROSS THESE AREAS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR CTZ009. NY...COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ072- 074-075-178-179. COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR NYZ071-073-176-177. NJ...COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR NJZ006- 106-108. MARINE...GALE WARNING UNTIL NOON EST TODAY FOR ANZ330-335-338-340-345- 350-353-355. && $$
AREA FORECAST DISCUSSION
NWS ALBANY NY
832 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING. ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000 FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING SNOWFLAKES TO COOL THE COLUMN. UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS WELL). ********PREVIOUS NEAR TERM FORECAST******** AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR THE SOUTHERN ADIRONDACKS. AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING TOWARD KPOU. REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR 20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT (NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH. ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL. IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM. OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND 40/45KTS THROUGH MUCH OF THE MORNING. EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH TIME. ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS. OUTLOOK... FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECOMING WINDY. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047>054-058-061-063-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...11/NAS NEAR TERM...HWJIV/11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...HWJIV HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
800 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR THE SOUTHERN ADIRONDACKS. AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /13Z THURSDAY THROUGH MONDAY/... AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING TOWARD KPOU. REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR 20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT (NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH. ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL. IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM. OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND 40/45KTS THROUGH MUCH OF THE MORNING. EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH TIME. ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS. OUTLOOK... FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECOMING WINDY. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047>054-058-061-063-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...11/NAS NEAR TERM...11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...HWJIV HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
657 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR THE SOUTHERN ADIRONDACKS. AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... WINTRY PRECIPITATION IMPACTING KALB AND KGFL BUT WILL SOON TRANSITION TO RAIN. MAINLY MVFR CONDITION WITH CIGS BELOW 2000 FEET THROUGH MUCH OF THE DAY. ONE BATCH OF HEAVIER SNOW WAS MOVING NORTH OF ALBANY. IN ITS WAKE...MUCH LIGHTER PRECIPITATION WHICH SHOULD BECOME MAINLY RAIN...EXCEPT STILL MIXED WITH SNOW AND SLEET AT KALB...AND EVEN A LITTLE FREEZING RAIN AT KGFL...THROUGH MID MORNING. OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND 40/45KTS THROUGH MUCH OF THE MORNING. THESE ESE FLOW WILL RESULT IN DOWNSLOPE OFF THE HIGHER TERRAIN TO THE EAST AND AS RESULT WILL LIKELY KEEP CIGS AND VSBY (ONCE THE PCPN TURNS TO RAIN)...ABOVE IFR...IN THE LOW MVFR RANGE. HOWEVER...CIGS LOOK TO REMAIN AT OR BELOW 2000 FEET MUCH OF THE DAY. EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH TIME. ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS. OUTLOOK... FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECOMING WINDY. SAT-MON...VFR...NO SIG WX. HWJIV OUTLOOK... THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BCMG WINDY FRI. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047>054-058-061-063-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...11/NAS NEAR TERM...11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...HWJIV HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ALBANY NY
512 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... AS OF 515 AM...SNOW HAS REACHED KGFL AND CONTINUED AT KALB. RAIN FALLING AT KPOU. WARMER AIR ALOFT....AND LIGHTER PCPN AMOUNTS WILL ALLOW THE PCPN TO MIX WITH SLEET AND RAIN AND EVENTUALLY CHANGE TO ALL RAIN LATER THIS MORNING. IFR CONDITIONS WILL LIKELY TRANSITION TO MVFR LATER THIS MORNING SINCE THE PCPN GOES TO RAIN AND WE ARE LOOKING AT AN EASTERLY DOWNSLOPE COMPONENT AT ALL TAF SITES. DUE TO THE STRENGTH OF THIS SYSTEM...LLWS DOES SEEM TO BE INCREASING AND EVIDENCE IS SHOWING UP IN THE VWP. SO WE WILL INCLUDE LLWS FOR ALL TAF SITES OVERNIGHT AND TOWARD SUNRISE THURSDAY. PRECIP WILL BEGIN TO TAPER OFF AS WE DRY SLOT THROUGH THE DAY THURSDAY. OUTLOOK... THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECMG WINDY FRI. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047>054-058-061-063-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...11/NAS NEAR TERM...11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...BGM HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
506 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS. EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS. THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI. POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S. SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR EXPECTED FOR THIS TIME OF THE YEAR. IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO. HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO SLIGHT CHC FOR THE REMAINDER OF SATURDAY. HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS. A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS. IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... THE ONSET OF THE PRECIP WAS ADVANCING NORTHWARD COINCIDING WITH IFR CONDITIONS AND INTERACTING WITH A VERY COMPLEX SURFACE TEMPERATURES. FOR KPOU...A MAINLY RAIN EVENT EXPECTED. FURTHER NORTH...A WINTRY MIXTURE FOR KALB THROUGH THIS EARLY THURSDAY MORNING. KGFL...MAINLY SNOW THROUGH THIS EARLY THURSDAY MORNING WITH A TRANSITION TOWARD SOME SLEET. AS WARMER AIR ADVANCES NORTHWARD...A PERIOD OF SLEET AND FREEZING RAIN IS EXPECTED BEFORE CHANGING OVER TO MAINLY RAIN TOWARD THE NOON HOUR. DUE TO THE STRENGTH OF THIS SYSTEM...LLWS DOES SEEM TO BE INCREASING AND EVIDENCE IS SHOWING UP IN THE VWP. SO WE WILL INCLUDE LLWS FOR ALL TAF SITES OVERNIGHT AND TOWARD SUNRISE THURSDAY. PRECIP WILL BEGIN TO TAPER OFF AS WE DRY SLOT THROUGH THE DAY THURSDAY. OUTLOOK... THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS SNOW. BECMG WINDY FRI. SAT-MON...VFR...NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS. TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001. NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041- 043-047>054-058-061-063-082>084. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032- 033-042. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025. WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001. VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015. WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014. && $$ SYNOPSIS...11/NAS NEAR TERM...11 SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...BGM HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1254 AM EST THU JAN 12 2012 .PREV DISCUSSION... /ISSUED 906 PM EST WED JAN 11 2012/ UPDATE... FORECAST IS ON TRACK TONIGHT. WILL CONTINUE TO SEE EXTENSIVE CLOUD COVERAGE OVERNIGHT BUT FOR THE MOST PART THE PRECIP HAS LIFTED OUT OF THE AREA. RUC PROGS A WEAK VORT MAX QUICKLY MOVING ACROSS THE STATE OVER THE NEXT FEW HOURS...BUT SEEING AS THIS ISNT PRODUCING SHOWERS IN AL...DO NOT EXPECT TO SEE ANY SHOWERS ASSOCIATED WITH IT HERE. CUT BACK ON POPS OVERNIGHT AND ONLY LEFT THEM IN ACROSS NORTHEAST GEORGIA. DID ADD PATCHY DRIZZLE THOUGH TONIGHT FOR EXTREME NORTH GEORGIA. 11 PREV DISCUSSION... SHORT TERM /TONIGHT THROUGH FRIDAY/... /ISSUED 254 PM EST WED JAN 11 2012/ SHOWERS AND ISOLATED THUNDERSTORMS REMAINED ACROSS NORTH GEORGIA THIS AFTERNOON AS A RESULT OF LOW PRESSURE MOVING THROUGH THE AREA. ASSOCIATED COLD FRONT EXPECTED TO MOVE INTO THE CAROLINAS THIS EVENING WILL HAVE LITTLE IMPACT TO THE CWA...AHEAD OF A SECOND COLD FRONT THAT WILL QUICKLY PUSH THROUGH ON THURSDAY. INITIALLY...WRAP AROUND MOISTURE WILL KEEP NORTH GEORGIA IN A FAVORABLE PRECIP AREA...BUT THIS MOISTURE...COMBINED WITH THE SOUTHERLY FLOW AHEAD OF THE NEXT FRONT...WILL BE ENOUGH TO KEEP SLIGHT CHANCE TO CHANCE POPS ACROSS MAINLY NORTH GEORGIA THROUGH THURSDAY AFTERNOON. BEHIND THIS BOUNDARY...MUCH COOLER TEMPERATURES MOVE INTO THE AREA...WHICH WITH SOME RESIDUAL MOISTURE...WILL BE ENOUGH TO PRODUCE LIGHT SNOW ACROSS NORTH GEORGIA. HAVE GONE WITH GENERALLY SLIGHT CHANCE TO CHANCE LIGHT SNOW ACROSS THE NORTHERNMOST TIER OF COUNTIES. MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS SOLUTION...AND DUE TO INCONVENIENCES THAT MAY RESULT FROM THIS PRECIP...CONFIDENCE IS HIGH ENOUGH TO GO AHEAD AND ISSUE THE WINTER WEATHER ADVISORY FOR 00Z TO 12Z FRIDAY. HPC WWD HAS THE AREA OUTLOOKED FOR 1 INCH OF ACCUMULATIONS...AND HAVE GENERALLY SIDED MORE TOWARDS THE 0.5 TO 1 INCH RANGE...WITH THE HIGHER AMOUNTS IN THE HIGHER ELEVATIONS. WITH WARM SURFACE TEMPERATURES...MOST OF THE ACCUMULATIONS WILL BE ON THE ELEVATED SURFACES. ADDITIONALLY...THE TIGHT PRESSURE GRADIENT OVER THE AREA RESULTING FROM THESE SERIES OF SYSTEMS WILL ALLOW FOR STRONG TO GUSTY WINDS TO IMPACT THE AREA ON THURSDAY. EXPECTING WINDS TO BE IN THE 15 TO 20 MPH RANGE...WITH GUSTS AS HIGH AS 35 MPH. HAVE ISSUED A WIND ADVISORY FOR ALL OF NORTH AND CENTRAL GEORGIA FOR 10 AM THURSDAY THROUGH MIDNIGHT. ONCE THE COLD FRONT PUSHES THROUGH THE STATE THURSDAY...ASSOCIATED PARENT LOW SWEEPS OVER NEW ENGLAND...AND PULLS ANY REMAINING WRAP AROUND MOISTURE UP THE APPALACHIANS DURING THE DAY FRIDAY. SURFACE HIGH PRESSURE BUILDS BACK INTO THE STATE...WITH DRY AND CHILLY CONDITIONS PREVAILING ACROSS THE STATE. MET OUT PERFORMED THE MAV ON THE TEMPERATURES YESTERDAY...AND EACH HAS ITS STRENGTHS WITH THE CURRENT FORECAST...ONE BETTER ON TEMPS...THE OTHER SEEMINGLY BETTER ON DEW POINTS. HAVE GENERALLY GONE WITH A BLEND OF THE TWO...AND HEAVILY WEIGHTING THE LOCAL BIAS NUMBERS. AS A RESULT...EXPECTING ONE LAST DAY WITH HIGHS IN THE MID 50S TO MID 60S ON THURSDAY. INFLUENCE OF THE COLD FRONT REALLY PROMINENT ON FRIDAY MORNING AS TEMPS DROP INTO THE 20S AND LOW 30S...AND WITH HIGHS ONLY IN THE 40S FRIDAY AFTERNOON. 31 LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... /ISSUED 254 PM EST WED JAN 11 2012/ SURFACE HIGH PRESSURE CONTROLS THE ENVIRONMENT THROUGH EARLY WEEK...WITH DRY CONDITIONS PREVAILING...AND CHILLY TEMPERATURES GRADUALLY WARMING. NEXT FRONTAL SYSTEM LOOKS TO MOVE INTO NORTHWEST GEORGIA THROUGH EARLY TUESDAY. HAVE MADE NO MAJOR CHANGES TO THE CURRENT FORECAST...AND SLIGHT CHANCE TO CHANCE POPS ARE STILL EXPECTED TUESDAY AS THIS NEXT SYSTEM ENTERS THE REGION. 31 && .AVIATION... 06Z UPDATE... EXPECT MVFR CIGS TO DOMINATE THROUGH MUCH OF THE PERIOD...THOUGH MAY SEE A BRIEF PERIOD OF CIGS IN THE IFR RANGE 10Z TO 14Z TIME FRAME. VSBYS GENERALLY UNRESTRICTED EXCEPT POSSIBLY LOWERING INTO THE MVFR RANGE THIS AFTERNOON/EARLY EVENING IN SCATTERED LIGHT SHOWERS AS A SECONDARY COLD FRONT MOVES ACROSS THE AREA. SOUTHWEST WINDS 8 TO 12 KTS REST OF THE NIGHT...BECOMING MORE WESTERLY AND INCREASING INTO THE 12 TO 18 KT RANGE BY MID MORNING THURSDAY WITH GUSTS UP TO 30 KTS POSSIBLE IN THE AFTERNOON WITH THE FRONT MOVING THROUGH. //ATL CONFIDENCE...06Z UPDATE... HIGH MOST ELEMENTS...EXCEPT MEDIUM ON THE DEVELOPMENT OF IFR CIGS THIS MORNING. 49 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 63 28 47 24 / 20 10 0 5 ATLANTA 58 28 45 26 / 30 10 0 5 BLAIRSVILLE 50 23 37 18 / 50 30 0 5 CARTERSVILLE 57 29 43 20 / 30 20 0 5 COLUMBUS 64 29 49 27 / 20 5 0 5 GAINESVILLE 53 30 42 25 / 30 20 0 5 MACON 65 30 50 24 / 20 10 0 5 ROME 56 28 42 20 / 50 20 0 10 PEACHTREE CITY 59 26 46 20 / 20 10 0 5 VIDALIA 68 31 51 31 / 5 10 0 5 && .FFC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT EST TONIGHT FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW... BIBB...BLECKLEY...BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE... CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...COWETA... CRAWFORD...CRISP...DADE...DAWSON...DEKALB...DODGE...DOOLY... DOUGLAS...EMANUEL...FANNIN...FAYETTE...FLOYD...FORSYTH... GILMER...GLASCOCK...GORDON...GREENE...GWINNETT...HALL... HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON... JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR... LAURENS...LUMPKIN...MACON...MADISON...MARION...MERIWETHER... MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...NEWTON... NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH... PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY... SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT... TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN... TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN... WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX... WILKES...WILKINSON. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST FRIDAY FOR THE FOLLOWING ZONES: CATOOSA...DADE...FANNIN... GILMER...LUMPKIN...MURRAY...TOWNS...UNION...WALKER...WHITE... WHITFIELD. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
335 PM CST THU JAN 12 2012 .DISCUSSION... 134 PM CST LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE IL/NW IN EARLY THIS EVENING. IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS AFTERNOON/EARLY THIS EVENING. MDB //PREV DISCUSSION... 1110 AM CST HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE. FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA. SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA. MDB //PREV DISCUSSION... 309 AM CST NEAR TERM (NOW THROUGH FRIDAY)... VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING. POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID MORNING AS FAR WEST AS ROCKFORD. AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID 4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT. IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF 10-15:1. INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN 8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE ADVISORY TO A WARNING. HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE. SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES FLUFFIER INCREASING ITS "BLOW-ABILITY". IZZI IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)... IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO -10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO. BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK SATURDAY NIGHT. IZZI LONG TERM (SUNDAY THROUGH WEDNESDAY)... THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY. THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS. A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO QUICK SNOW MELT AND POSSIBLY ADVECTION FOG. BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER. THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS PERIOD IS LOW. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEST/NORTHWEST WINDS SLOWLY INCREASING THROUGH THE REMAINDER OF THE AFTERNOON WITH THE STRONGER GUSTS EXPECTED LATE THIS AFTERNOON/EARLY EVENING. * PREVAILING IFR CEILINGS STILL EXPECTED THROUGH THE REMAINDER OF THE DAY/NIGHT. * LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH PERIODS OF HEAVIER SNOW STILL POSSIBLE. VIS OF 1/2SM EXPECTED WITH PERIODS OF 1/4SM. RODRIGUEZ //DISCUSSION...UPDATED 18Z... LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM SLOWLY TRANSITIONS TO THE EAST. WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING. WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY MORNING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. * MEDIUM HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT. * MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY THE AFTERNOON AND CONTINUING INTO THE NIGHT. SUNDAY...VFR. WX NIL. MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN. TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 335 PM CST LOW PRESSURE OF OVER THE FAR SOUTH END OF LAKE HURON AT MID AFTERNOON DEEPENS AS IT MOVES EAST OVER THE LOWER GREAT LAKES TONIGHT...AND THEN NORTHEAST UP THE ST. LAWRENCE VALLEY ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL GRADUALLY MOVE FROM MANITOBA TO WESTERN ONTARIO. THE STRONG PRESSURE GRADIENT BETWEEN THE LOW AND THE HIGH...ALONG WITH A SURGE OF COLD AIR...WILL RESULT IN GALE FORCE WINDS TONIGHT AND INTO FRIDAY AFTERNOON. WINDS WILL BEGIN TO RELAX LATER FRIDAY AS THE LOW MOVES FARTHER AWAY AND HIGH PRESSURE MOVES SOUTHEAST ACROSS ONTARIO. LOW PRESSURE OF MOVES SOUTHEAST ACROSS THE CANADIAN PRAIRIE PROVIDENCES FRIDAY NIGHT BUT THEN WEAKENS AS IT CONTINUES ON TO THE UPPER GREAT LAKES SATURDAY. ANOTHER LOW WILL MOVE EAST ACROSS SOUTH CENTRAL CANADA SATURDAY NIGHT THROUGH SUNDAY NIGHT...THEN TURN NORTHEASTWARD AND REACH JAMES BAY MONDAY NIGHT. DEPENDING ON THE STRENGTH OF THIS LOW IT COULD POTENTIALLY PRODUCE GALES TUESDAY AND TUESDAY NIGHT. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020- ILZ022 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY. IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL MIDNIGHT SATURDAY. GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
224 PM CST THU JAN 12 2012 .DISCUSSION... 134 PM CST LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE IL/NW IN EARLY THIS EVENING. IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS AFTERNOON/EARLY THIS EVENING. MDB //PREV DISCUSSION... 1110 AM CST HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE. FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA. SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA. MDB //PREV DISCUSSION... 309 AM CST NEAR TERM (NOW THROUGH FRIDAY)... VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING. POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID MORNING AS FAR WEST AS ROCKFORD. AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID 4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT. IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF 10-15:1. INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN 8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE ADVISORY TO A WARNING. HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE. SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES FLUFFIER INCREASING ITS "BLOW-ABILITY". IZZI IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)... IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO -10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO. BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK SATURDAY NIGHT. IZZI LONG TERM (SUNDAY THROUGH WEDNESDAY)... THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY. THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS. A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO QUICK SNOW MELT AND POSSIBLY ADVECTION FOG. BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER. THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS PERIOD IS LOW. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEST/NORTHWEST WINDS SLOWLY INCREASING THROUGH THE REMAINDER OF THE AFTERNOON WITH THE STRONGER GUSTS EXPECTED LATE THIS AFTERNOON/EARLY EVENING. * PREVAILING IFR CEILINGS STILL EXPECTED THROUGH THE REMAINDER OF THE DAY/NIGHT. * LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH PERIODS OF HEAVIER SNOW STILL POSSIBLE. VIS OF 1/2SM EXPECTED WITH PERIODS OF 1/4SM. RODRIGUEZ //DISCUSSION...UPDATED 18Z... LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM SLOWLY TRANSITIONS TO THE EAST. WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING. WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY MORNING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. * MEDIUM HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT. * MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY THE AFTERNOON AND CONTINUING INTO THE NIGHT. SUNDAY...VFR. WX NIL. MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN. TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 309 AM CST A LOW PRESSURE SYSTEM OVER OHIO WILL MOVE INTO MICHIGAN THIS AFTERNOON AND STRENGTHEN. IN ADDITION...ARCTIC AIR WILL POUR INTO THE REGION TODAY. BETWEEN THESE TWO COMPONENTS...LOW END GALES WILL FORM ACROSS LAKE MICHIGAN TODAY. WINDS WILL BE NORTH TO NORTHWEST ALONG THE LAKE...THEREFORE EXPECTING GALES TO LEAK INTO THE INDIANA NEARSHORE ZONES AS WELL. UPGRADED THE GALE WATCH TO A GALE WARNING WITH THIS ISSUANCE. THE LOW QUICKLY MOVES EASTWARD FRIDAY AND HIGH PRESSURE MOVES IN BEHIND IT FRIDAY NIGHT INTO SATURDAY. WINDS WILL BECOME WESTERLY AND DIMINISH QUICKLY BEHIND THE LOW...BUT EXPECTING HIGH WAVES TO PERSIST THROUGH EARLY FRIDAY NIGHT IN THE NEARSHORE ZONES. A WEAKENING LOW PRESSURE SYSTEM PASSES SOUTH OF THE LAKE LATE SATURDAY...AND WILL HAVE LITTLE TO NO IMPACT ON THE LAKE. WINDS REMAIN WEAK THROUGH THE WEEKEND BUT BEGIN TO TURN SOUTHERLY AND INCREASE SUNDAY EVENING AS THE PRESSURE GRADIENT INCREASES BETWEEN HIGH PRESSURE OVER THE ATLANTIC COAST AND A DEVELOPING LOW PRESSURE SYSTEM OVER MANITOBA. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020- ILZ022 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY. IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL MIDNIGHT SATURDAY. GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
139 PM CST THU JAN 12 2012 .DISCUSSION... 134 PM CST LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE IL/NW IN EARLY THIS EVENING. IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS AFTERNOON/EARLY THIS EVENING. MDB && .PREV DISCUSSION... 1110 AM CST HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE. FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA. SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA. MDB //PREV DISCUSSION... 309 AM CST NEAR TERM (NOW THROUGH FRIDAY)... VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING. POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID MORNING AS FAR WEST AS ROCKFORD. AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID 4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT. IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF 10-15:1. INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN 8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE ADVISORY TO A WARNING. HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE. SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES FLUFFIER INCREASING ITS "BLOW-ABILITY". IZZI IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)... IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO -10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO. BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK SATURDAY NIGHT. IZZI LONG TERM (SUNDAY THROUGH WEDNESDAY)... THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY. THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS. A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO QUICK SNOW MELT AND POSSIBLY ADVECTION FOG. BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER. THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS PERIOD IS LOW. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WEST/NORTHWEST WINDS BECOMING MORE NORTHWEST AND SLOWLY INCREASING THROUGH THE EARLY AFTERNOON WITH THE STRONGER GUSTS NOT EXPECTED UNTIL LATE THIS AFTERNOON/EARLY EVENING. * IFR CEILINGS THROUGH THE REMAINDER OF THE DAY/NIGHT. * LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH SNOW EXPECTED TO INCREASE LATER THIS AFTERNOON WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS OF 1/2SM EXPECTED WITH PERIODS OF 1/4SM. * LIGHT SNOW TO SLOWLY DIMINISH TONIGHT INTO EARLY FRIDAY MORNING WITH VIS SLOWLY IMPROVING. RODRIGUEZ //DISCUSSION...UPDATED 18Z... LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM SLOWLY TRANSITIONS TO THE EAST. WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING. WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY MORNING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. * HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT. * MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY THE AFTERNOON AND CONTINUING INTO THE NIGHT. SUNDAY...VFR. WX NIL. MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN. TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 309 AM CST A LOW PRESSURE SYSTEM OVER OHIO WILL MOVE INTO MICHIGAN THIS AFTERNOON AND STRENGTHEN. IN ADDITION...ARCTIC AIR WILL POUR INTO THE REGION TODAY. BETWEEN THESE TWO COMPONENTS...LOW END GALES WILL FORM ACROSS LAKE MICHIGAN TODAY. WINDS WILL BE NORTH TO NORTHWEST ALONG THE LAKE...THEREFORE EXPECTING GALES TO LEAK INTO THE INDIANA NEARSHORE ZONES AS WELL. UPGRADED THE GALE WATCH TO A GALE WARNING WITH THIS ISSUANCE. THE LOW QUICKLY MOVES EASTWARD FRIDAY AND HIGH PRESSURE MOVES IN BEHIND IT FRIDAY NIGHT INTO SATURDAY. WINDS WILL BECOME WESTERLY AND DIMINISH QUICKLY BEHIND THE LOW...BUT EXPECTING HIGH WAVES TO PERSIST THROUGH EARLY FRIDAY NIGHT IN THE NEARSHORE ZONES. A WEAKENING LOW PRESSURE SYSTEM PASSES SOUTH OF THE LAKE LATE SATURDAY...AND WILL HAVE LITTLE TO NO IMPACT ON THE LAKE. WINDS REMAIN WEAK THROUGH THE WEEKEND BUT BEGIN TO TURN SOUTHERLY AND INCREASE SUNDAY EVENING AS THE PRESSURE GRADIENT INCREASES BETWEEN HIGH PRESSURE OVER THE ATLANTIC COAST AND A DEVELOPING LOW PRESSURE SYSTEM OVER MANITOBA. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020- ILZ022 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY. IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY. WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL MIDNIGHT SATURDAY. GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
206 AM CST THU JAN 12 2012 .DISCUSSION... 840 PM CST AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID. RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN. ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME. A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID- LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR POSSIBLE UPGRADE TO A WARNING IN TIME. THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR CHICAGOLAND ON TOTALS. MTF //PREV DISCUSSION... 243 PM CST WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT... HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY. STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING. SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN. MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1 LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1 THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5 INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24 HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6 INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25 MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO -10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING. THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS. RATZER LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK... THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK. REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO BELOW NORMAL TO CLOSE OUT THE WEEKEND. RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND. SHEA && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 08Z... * CEILINGS LOWING TO MVFR BY ARND 10Z...LOWERING TO IFR SHORTLY AFTER THE SNOW ONSET. * SNOW DEVELOPING BY ARND 16Z AND CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD. * VIS DROPPING TO IFR LIKELY SHORTLY AFTER SNOW ONSET. PERIODS OF 1/2SM VIS LIKELY FROM LATE AFTERNOON THROUGH THE EVENING WITH INCREASING SNOWFALL RATES AND INCREASING WINDS. * CHANCE OF VIS DROPPING TO 1/4SM OR LESS DURING THE EARLY EVENING AS BLOWING SNOW DEVELOPS AS DECREASING TEMPERATURES CAUSE A DRIER SNOW CHARACTERISTIC. KREIN //DISCUSSION...UPDATED 06Z... NOT MUCH CHANGE FROM PREVIOUS THINKING. THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS STILL SET TO IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING. THE MAIN COLD FRONT IS NOW MOVING ACROSS NORTH CENTRAL IL NEAR KRFD. THIS FRONT SHOULD MOVE ACROSS NORTHEASTERN ILLINOIS AFTER 07 UTC TONIGHT. BEHIND THIS FRONT...EXPECT WINDS TO BECOME GUSTY OUT OF THE NORTHWEST. THE MAIN SURFACE LOW MOVING NORTH ACROSS THE OHIO VALLEY LATE THIS EVENING...WILL QUICKLY INTENSIFY DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER OF THE FORECAST PERIOD. AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING THE MID TO LATE MORNING HOURS (AFTER 16 UTC AT THE NORTHEASTERN ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE LOW. I EXPECT THE ONSET TIME TO OCCUR AROUND OR SHORTLY AFTER 12 UTC AT KRFD. THE SNOW SHOULD PICK UP IN INTENSITY DURING THE AFTERNOON HOURS (AFTER 19 UTC) AS THE DYNAMICS REACH A PEAK ALONG THE LEADING EDGE OF THE COLDEST AIR. THIS STILL APPEARS TO POSSIBLY RESULT IN A PERIOD OF VISIBILITIES IN SNOW AND BLOWING SNOW UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE SNOWFALL SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY MORNING AS THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT LAKES. KJB //ORD AND MDW CONFIDENCE...UPDATED 08Z... * HIGH CONFIDENCE WITH CEILING AND WIND TRENDS. * HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS TRENDS ON THURSDAY. * LOWER CONFIDENCE IN THE PROBABILITY OF VISIBILITY OCCASIONALLY DROPPING TO 1/4SM OR LESS KREIN //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS IMPROVING THROUGH THE DAY. SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. SUNDAY...VFR. MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS. KJB && .MARINE... 145 PM CST LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND MONDAY. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014- ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM FRIDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM THURSDAY TO 9 AM FRIDAY. LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON THURSDAY TO MIDNIGHT SATURDAY. SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1116 PM CST WED JAN 11 2012 .DISCUSSION... ISSUED 845 PM CST WED JAN 11 2012 QUICK GLANCE AT THE 00Z NAM...AS WELL AS THE HRRR AND RUC MODELS... INDICATES NO BIG CHANGES NEEDED TO HEADLINES OR SNOW SCENARIO FORECAST. COLD FRONT NOW APPROACHING THE IL RIVER WITH GUSTY NORTHWEST WINDS AND LOW CLOUDS. RADARS INDICATE THE SNOW IS LAGGING BACK OVER CENTRAL IA...SO NO POPS THIS EVENING STILL LOOK ON TRACK. THE NAM AND HRRR MODELS INDICATE THE LEADING EDGE OF THE SNOW REACHING THE MIDDLE OF THE FORECAST AREA BY 12Z. WATER VAPOR LOOPS SHOWING THE DEEPENING/AMPLIFYING TROUGH OVER THE PLAINS...WITH INCREASING INFLECTION OVER NEB BEING THE BEGINNINGS OF THE LOW CLOSING OFF. THE EXPANDING DARK AREA ON SATELLITE ALONG THE TROF AXIS AND DOWN INTO THE INFLECTION OVER SOUTHERN NEB AND NORTHWESTERN KS SUGGESTS THAT STRATOSPHERIC POTENTIAL VORTICITY IS POKING DOWNWARD ON THE WESTERN FLANK OF THE TROUGH...WHICH WILL ACT TO ACCELERATE THE DEEPENING PROCESS. MOST OF THE SYNOPTIC MODEL OUTPUT AGREES ON TRACKING THE CENTER OF THE DEEPENING UPPER LOW ACROSS THE SOUTHERN THIRD OF IL FROM LATE MORNING TO LATE AFTERNOON THURSDAY. DURING THAT TIME...PV AND DIFLUENCE WILL BE ROTATING THROUGH THE EASTERN QUADRANT AND INTO THE NORTHEASTERN QUADRANT OF THE LOW...WHICH WILL EXTEND EAST/WEST THROUGH CENTRAL IL. IN ADDITION...ISENTROPIC ANALYSES INDICATE A DECENT UPGLIDE ON THE 300K-290K SURFACES IN THE SAME GENERAL AREA...WITH SPECIFIC HUMIDITIES OF 1.5-2.5 G/KG. SO SNOW AMOUNTS OF 3-5 INCHES OVER THE NORTHERN HALF OF THE AREA STILL LOOK GOOD...WITH POSSIBLE MESOSCALE ENHANCEMENT OF SNOW BANDS. WILL FRESHEN UP THE WINTER WEATHER ADVISORY PRODUCT SHORTLY. 04 && .AVIATION... ISSUED 1116 PM CST WED JAN 11 2012 UPPER LOW CONTINUES TO DEEPEN AS IT MOVES SOUTHEASTWARD ACROSS NEB. THE LOW WILL MOVE THROUGH MO THEN ACROSS IL TO THE SOUTH OF THE TAF SITES ON THURSDAY. COLD FRONT AHEAD OF THIS LOW HAS ALREADY MADE IT THROUGH ALMOST ALL TERMINALS...AND IT IS NOT FAR FROM CMI. 15-25 KT NORTHWESTERLY WINDS WILL INCREASE ON THURSDAY WITH GUSTS 30-35 KT. MVFR 1K-2K FT STRATOCU IS CURRENTLY AN HOUR OR SO BEHIND THE FRONT...BUT THE SNOW IS STILL LAGGING BACK IN EASTERN IA AND CENTRAL MO. AT THE CURRENT RATE OF MOVEMENT...THE SNOW SHOULD BE MOVING INTO THE PIA/SPI AREAS AROUND 12Z OR SHORTLY THEREAFTER. IFR CONDITIONS OR LOWER IN SNOW/BLOWING SNOW WILL BE COMMON MUCH OF THURSDAY. SNOW RATES WILL BE DECREASING SOMEWHAT AFTER 00Z FRI AS THE SYSTEM MOVES OFF...BUT LOW CIGS AND LIGHT SNOW/BLOWING SNOW WILL CONTINUE THROUGH AT LEAST 06Z. 04 && .PREV DISCUSSION... ISSUED 220 PM CST WED JAN 11 2012 SNOW...WIND AND MUCH COLDER WEATHER HEADING FOR CENTRAL...EAST CENTRAL AND SOUTHEAST ILLINOIS THURSDAY INTO FRIDAY. SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW SOUTH OF THE OHIO RIVER SPREAD RAIN AS FAR NORTH AS SPRINGFIELD EAST NORTHEAST TO CHAMPAIGN. FURTHER NORTH AND WEST...SUNSHINE HAS BROUGHT EARLY AFTERNOON TEMPERATURES INTO THE MID AND UPPER 50S. THE COLD FRONT WHICH WILL BRING A DRASTIC CHANGE IN OUR WEATHER AS PUSHING THRU CENTRAL IOWA EARLY THIS AFTERNOON WITH TEMPERATURES STRUGGLING THRU THE SINGLE DIGITS AND LOW TEENS OVER THE DAKOTAS. SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT SNOW AMOUNTS...FALLING TEMPERATURES AND GUSTY WINDS THE MAIN FORECAST CONCERN THROUGH LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING. CONDITIONS ARE EXPECTED TO DETERIORATE RAPIDLY TOMORROW MORNING WEST...AND OVER THE EAST BY EARLY AFTERNOON. MODELS IN DECENT AGREEMENT WITH THE MOVEMENT OF THE SOUTHERN STREAM UPPER LEVEL WAVE AS IT GETS ABSORBED BY THE STRONGER NORTHERN STREAM ENERGY LATER TOMORROW WHICH IN EFFECT WILL PRODUCE A DEEPENING SURFACE WAVE WHICH IS FORECAST TO TRACK NORTH INTO EASTERN LOWER MICHIGAN BY 00Z FRIDAY. SNOW SHOULD TRACK INTO FAR WESTERN IL BETWEEN 09Z AND 12Z AFFECTING THE MORNING COMMUTE MAINLY IN AREAS WEST OF INTERSTATE 55 WITH LOCATIONS TO THE EAST SEEING THE SNOW DEVELOP BY MID TO LATE MORNING. THE COMMUTE HOME TOMORROW EVENING LOOKS TO BE A REAL MESS. NAM-WRF TIME HEIGHT CROSS SECTIONS SHOWING THE BEST DEEP LAYERED MOISTURE AND OMEGA COINCIDENT WITH THE SNOW GROWTH REGION TO BE OCCURRING FROM MID MORNING TO LATE AFTERNOON WEST AND LATE MORNING INTO THE EVENING HOURS EAST. TEMPERATURES THRU THE DAY WILL BE STEADY OR SLOWLY FALLING WITH FRIDAY MORNING LOWS IN THE 10 TO 15 DEGREE RANGE. LOOKING AT BOTH THE NAM AND GFS ISENTROPIC PROFILES AT 290K...SUGGEST THE BEST ASCENT AND LOWEST PRESSURE DEFICITS OCCUR IN THE 00Z TO 06Z TIME FRAME WITH THE BETTER LIFT SHIFTING OFF TO OUR EAST LATE THURSDAY NIGHT/FRIDAY MORNING. MODELS SUGGEST SOME DECENT 850-500 MB FRONTOGENETICAL FORCING COUPLED WITH WEAK STATIC STABILITY INDICATING THE POTENTIAL FOR SOME BANDED SNOWFALL...ESPECIALLY ACROSS OUR NORTH LATER TOMORROW MORNING INTO THE AFTERNOON HOURS. SNOW RATIOS START OUT AT 13:1 BUT FORECAST SOUNDINGS SUGGEST 16:1 OR EVEN GREATER TOWARDS LATE THU AFTN AND EVENING. HIGHEST SNOW AMOUNTS CONTINUE TO BE ALONG AND NORTH OF I-74 WHERE 3 TO 5 INCHES WILL OCCUR...WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE...ESPECIALLY IN OUR FAR NORTHEASTERN AREAS. FURTHER SOUTH...TOTAL SNOW AMOUNTS LOOK TO BE IN THE ORDER OF 1 TO 3 INCHES WITH AN INCH OR TWO ALONG AND SOUTH OF I-70. ISSUED THE WINTER WEATHER ADVISORY EARLIER AND WILL CONTINUE WITH IT ACROSS THE ENTIRE FORECAST AREA INTO FRIDAY MORNING. AS THE SURFACE SYSTEM DEEPENS LATER TONIGHT INTO THUR...NW WINDS WILL INCREASE TO BETWEEN 20 TO 25 MPH...WITH OCCASIONAL GUSTS APPROACHING 35 MPH...PRODUCING QUITE A BIT OF BLOWING SNOW. WINDS SHOULD GRADUALLY DECREASE FRIDAY MORNING AS THE LOW PULLS WELL OFF TO OUR EAST. WIND CHILLS DROP INTO THE SINGLE DIGITS NORTHWEST BY TOMORROW AFTN...AND DOWN TO BETWEEN -3 TO -8 FRIDAY MORNING. TRANQUIL WEATHER WILL RETURN FRIDAY AFTN INTO FRIDAY NIGHT WITH SOME RATHER NIPPY TEMPERATURES IN STORE FOR THE AREA...ESPECIALLY WITH A FRESH SNOW PACK IN PLACE. WENT BELOW MOST GUID VALUES FRI NIGHT/SAT MORNING WITH OUR NORTH SEEING SINGLE DIGITS FOR LOWS. HOWEVER...IF OUR NEXT WEATHER SYSTEM TRACKING IN FROM THE NORTHWEST ON SATURDAY IS QUICKER THAN WHAT MODELS INDICATE...CLOUDS MAY GET INTO THE AREA FASTER WHICH WOULD HELP KEEP THE TEMPS UP. FOR NOW... WL GO WITH THE COLDER LOWS EARLY SATURDAY MORNING. CLIPPER SYSTEM TRACKING QUICKLY SOUTHEAST INTO THE AREA ON SATURDAY BRINGING A THREAT OF LIGHT SNOW TO THE AREA...ESPECIALLY ACRS THE NORTHEAST HALF OF THE FORECAST AREA. GFS AND ECMWF IS FURTHEST SOUTH WHICH WOULD BRING SOME LIGHT ACCUMULATING SNOWS TO OUR NORTH...WHILE THE NAM WAS A BIT FURTHER NORTH AND NOT NEARLY AS AGGRESSIVE WITH THE QPF. FOR NOW...WILL KEEP LOW CHANCE POPS GOING ACRS THE NORTH AND EAST. LONG TERM...SUNDAY THROUGH WEDNESDAY UPPER LEVEL HEIGHTS REBOUND OVER THE MIDWEST SUNDAY INTO MONDAY WHICH WILL SPELL WARMER WEATHER RETURNING TO THE AREA. DESPITE THE SNOW COVER...WE SHOULD SEE AFTERNOON TEMPS PUSH BACK INTO THE UPPER 20S TO MIDDLE 30S ON SUNDAY...AND UPPER 30S TO MIDDLE 40S BY MONDAY WITH INCREASING SOUTHERLY WINDS. OUR NEXT WEATHER SYSTEM LOOKS TO AFFECT THE AREA LATE MONDAY INTO MONDAY NIGHT WITH TEMP PROFILES WARM ENOUGH TO SUPPORT MOSTLY RAIN WITH POSSIBLY A CHANGEOVER TO LIGHT SNOW OR FLURRIES AS THE SYSTEM PULLS AWAY AND COLDER AIR IS DRAWN SOUTHEAST INTO OUR AREA ON TUES. AFTER A BRIEF SHOT OF COLD AIR MIDWEEK...A MORE ZONAL FLOW PATTERN WILL DEVELOP ACROSS THE LOWER 48 RESULTING IN TEMPS AOA NORMAL FOR THE REMAINDER OF THE WEEK. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO 9 AM CST FRIDAY FOR ILZ038-043>046-052>057-061>063-066>068-071>073. WINTER WEATHER ADVISORY FROM 6 AM THURSDAY TO 6 AM CST FRIDAY FOR ILZ027>031-036-037-040>042-047>051. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1046 PM CST WED JAN 11 2012 .DISCUSSION... 840 PM CST AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID. RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN. ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME. A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID- LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR POSSIBLE UPGRADE TO A WARNING IN TIME. THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR CHICAGOLAND ON TOTALS. MTF //PREV DISCUSSION... 243 PM CST WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT... HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY. STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING. SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN. MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1 LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1 THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5 INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24 HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6 INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25 MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO -10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING. THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS. RATZER LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK... THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK. REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO BELOW NORMAL TO CLOSE OUT THE WEEKEND. RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND. SHEA && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOWERING CEILINGS LATE TONIGHT/EARLY THURSDAY MORNING...WITH MVFR CEILINGS BECOMING IFR ON THURSDAY. * SNOW DEVELOPING BY MID TO LATE THURSDAY MORNING AND CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD. * LIKELY A SEVERAL HOUR PERIOD OF IFR TO LIFR VIS THURSDAY AFTERNOON INTO THE EVENING IN SNOW AND BLOWING SNOW. KJB //DISCUSSION...UPDATED 06Z... NOT MUCH CHANGE FROM PREVIOUS THINKING. THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS STILL SET TO IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING. THE MAIN COLD FRONT IS NOW MOVING ACROSS NORTH CENTRAL IL NEAR KRFD. THIS FRONT SHOULD MOVE ACROSS NORTHEASTERN ILLINOIS AFTER 07 UTC TONIGHT. BEHIND THIS FRONT...EXPECT WINDS TO BECOME GUSTY OUT OF THE NORTHWEST. THE MAIN SURFACE LOW MOVING NORTH ACROSS THE OHIO VALLEY LATE THIS EVENING...WILL QUICKLY INTENSIFY DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER OF THE FORECAST PERIOD. AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING THE MID TO LATE MORNING HOURS (AFTER 16 UTC AT THE NORTHEASTERN ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE LOW. I EXPECT THE ONSET TIME TO OCCUR AROUND OR SHORTLY AFTER 12 UTC AT KRFD. THE SNOW SHOULD PICK UP IN INTENSITY DURING THE AFTERNOON HOURS (AFTER 19 UTC) AS THE DYNAMICS REACH A PEAK ALONG THE LEADING EDGE OF THE COLDEST AIR. THIS STILL APPEARS TO POSSIBLY RESULT IN A PERIOD OF VISIBILITIES IN SNOW AND BLOWING SNOW UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE SNOWFALL SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY MORNING AS THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT LAKES. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH CEILINGS AND TRENDS LATE TONIGHT/EARLY THURSDAY. * HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS TRENDS ON THURSDAY. * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. KJB //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS IMPROVING THROUGH THE DAY. SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. SUNDAY...VFR. MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS. KJB && .MARINE... 145 PM CST LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND MONDAY. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014- ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM FRIDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM THURSDAY TO 9 AM FRIDAY. LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON THURSDAY TO MIDNIGHT SATURDAY. SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 PM CST WED JAN 11 2012 .DISCUSSION... 840 PM CST AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID. RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN. ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME. A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID- LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR POSSIBLE UPGRADE TO A WARNING IN TIME. THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR CHICAGOLAND ON TOTALS. MTF //PREV DISCUSSION... 243 PM CST WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT... HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY. STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING. SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN. MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1 LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1 THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5 INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24 HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6 INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25 MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO -10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING. THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS. RATZER LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK... THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK. REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO BELOW NORMAL TO CLOSE OUT THE WEEKEND. RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND. SHEA && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 04Z... * LOWERING CEILINGS LATE TONIGHT/EARLY THURSDAY MORNING...WITH MVFR CEILINGS BECOMING IFR ON THURSDAY. * SNOW DEVELOPING BY MID TO LATE THURSDAY MORNING AND CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD. * LIKELY SEVERAL HOUR PERIOD OF IFR TO LIFR VIS THURSDAY AFTERNOON INTO THE EVENING IN SNOW AND BLOWING SNOW. KJB //DISCUSSION...UPDATED 00Z... THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS SET TO IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING. THE MAIN COLD FRONT IS NOW MOVING ACROSS EASTERN IOWA. THIS FRONT SHOULD MOVE ACROSS NORTHEASTERN ILLINOIS AFTER 06 UTC TONIGHT. BEHIND THIS FRONT...EXPECT WINDS TO BECOME GUSTY OUT OF THE NORTHWEST LATER TONIGHT. THE MAIN SURFACE LOW WILL QUICKLY INTENSIFY DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER OF THE FORECAST PERIOD. AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING THE MID TO LATE MORNING HOURS (AFTER 15 UTC AT THE NORTHEASTERN ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE LOW. EXPECT THE ONSET TIME A FEW HOURS SOONER AT KRFD. THE SNOW SHOULD PICK UP IN INTENSITY DURING THE AFTERNOON HOURS (AFTER 19 UTC) AS THE DYNAMICS REACH A PEAK ALONG THE LEADING EDGE OF THE COLDEST AIR. THIS COULD LEAD TO A PERIOD OF VISIBILITIES IN SNOW AND BLOWING SNOW UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE SNOWFALL SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY MORNING AS THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT LAKES. KJB //ORD AND MDW CONFIDENCE...UPDATED 04Z... * HIGH CONFIDENCE WITH CEILINGS AND TRENDS LATE TONIGHT/EARLY THURSDAY. * HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS TRENDS ON THURSDAY. * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. KJB //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS IMPROVING THROUGH THE DAY. SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS. SUNDAY...VFR. MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS. KJB && .MARINE... 145 PM CST LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND MONDAY. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011- ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY. WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014- ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM FRIDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9 AM THURSDAY TO 9 AM FRIDAY. LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM THURSDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON THURSDAY TO MIDNIGHT SATURDAY. SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
345 PM EST THU JAN 12 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS...A STRONG COLD FRONT WILL SWEEP ACROSS CENTRAL INDIANA...USHERING AN ARCTIC AIRMASS INTO CENTRAL INDIANA FOR THE NEXT FEW DAYS. AN UPPER LEVEL LOW PRESSURE SYSTEM WILL EXIT THE STATE TONIGHT...HOWEVER...MOISTURE WRAPPING AROUND THE LOW WILL LIKELY RESULT IN SCATTERED SNOW SHOWERS...PARTICULARLY THIS EVENING. THE STRONG LOW WILL LINGER ACROSS THE NORTHEAST UNITED STATE ON FRIDAY...PROVIDING A COLD...ARCTIC FLOW OF AIR TO CENTRAL INDIANA. A FEW SNOW SHOWERS CANNOT BE RULED OUT ON FRIDAY. A QUICK MOVING RIDGE OF HIGH PRESSURE WILL PUSH ACROSS THE STATE FRIDAY NIGHT AND SATURDAY...PROVIDING MORE COLD...CLOUDY...BUT DRY WEATHER. ANOTHER UPPER LEVEL DISTURBANCE WILL PUSH INTO THE STATE FROM THE NORTHWEST ON SATURDAY NIGHT AND SUNDAY...AND THIS MAY PROVIDE ANOTHER BRIEF ROUND OF SNOW SHOWERS. THE COLD AIR IS EXPECTED TO EXIT EARLY NEXT WORK WEEK AS THE FLOW ALOFT BECOMES MORE WESTERLY USHERING MILD PACIFIC AIR BACK TO THE OHIO VALLEY. && .NEAR TERM /TONIGHT/... SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHERN ONTARIO EARLY THIS AFTERNOON AND A COLD FRONT STRETCHED SOUTH ACROSS WESTERN OHIO. MUCH COLDER AIR WAS FOUND ACROSS CENTRAL ILLINOIS AND WESTERN CENTRAL INDIANA WHERE TEMPERATURES WERE IN THE TEENS. WATER VAPOR IMAGERY INDICATE THE UPPER LOW OVER SE MISSOURI...DRIVING EASTWARD. RADAR TRENDS SHOW MUCH DRIER AIR WRAPPING IN TO THE SYSTEM FROM THE SOUTHWEST. MODELS AGREE THAT THE UPPER SYSTEM WILL PUSH ACROSS THE STATE TONIGHT...HOWEVER BEST FORCING IS LOST AFTER 06Z. POTENTIAL VORTICITY MUCH DRIER ARRIVING ALONG WITH SUBSIDENCE AFTER 06Z...HOWEVER FORECAST SOUNDINGS CONTINUE TO SUGGEST DEEP SATURATION. ALSO 850MB POTENTIAL TEMPERATURE SURFACE SHOWS A WEAK TROWAL WORKING ACROSS THE STATE...BUT EXITING AFTER 06Z. THUS WILL KEEP POPS GOING INTO THE EVENING HOURS AS FORCING WILL BE FAVORABLE...HOWEVER WILL TAPER POPS OFF AFTER 06Z AS BEST DYNAMIC SHIFT WELL TO THE NORTHEAST. GIVEN THE DRY AIR WORKING INTO THE AREA ALONG WITH THE FORCING ENDING BY 06Z...FEEL THAT SNOW AMOUNTS ARE MORE LIKELY TO END UP AT THE LOWER END OF THE ADVISORY CRITERIA. AS FOR TEMPS WILL TREND COOLER THAN MAVMOS GIVEN THE STRONG COLD AIR ADVECTION. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... MODELS REMAIN IN PRETTY GOOD OVERALL AGREEMENT DURING THIS PERIOD AND WILL USE A BLEND. BROAD CYCLONIC FLOW WILL REMAIN IN PLACE ON FRIDAY AS THE UPPER LOW DEPARTS AND FORECAST SOUNDINGS INDICATE DEEP SATURATION BUT MINIMAL FORCING THROUGH 18Z. SOUNDINGS BEGIN TO DRY OUT AFTER 18Z AS THE COLD ARCTIC AIR MASS BEGINS TO SETTLE IN. THUS WILL CONTINUE LOW CHANCE POPS DURING THE MORNING HOURS...BUT TAPER OFF TO A DRY FORECAST IN THE AFTERNOON AS DRIER AIR ARRIVES. WILL TREND COLDER THAN MAVMOS FOR HIGHS. COLD NORTHWEST FLOW WILL PERSIST ALOFT ON FRIDAY NIGHT AND ANOTHER WEAK DISTURBANCE WILL PUSH ACROSS THE STATE. HOWEVER MOISTURE IS LIMITED AND NO PRECIP WILL BE EXPECTED. FURTHERMORE WITH A FRESH SNOW COVER AND 850MB TEMPS THAT HAVE FALLEN TO NEAR -11C...WILL TREND LOWS COLDER THAN MAVMOS. ANOTHER STRONGER UPPER DISTURBANCE WILL PUSH INTO THE AREA ON SATURDAY AND SATURDAY NIGHT. GFS IS MUCH DRIER THAN THE NAM. GIVEN THE EXPECTED FORCING...FEEL THAT THE NAM HANDLES THE SITUATION HERE AND LOW POPS APPEAR NEEDED. WITH COLD AIR IN PLACE PRECIP TYPE WILL BE SNOW AS THIS CLIPPER MOVES THROUGH. AGAIN GIVEN THE EXPECTED CLOUDS WILL TREND HIGHS ON SATURDAY COLDER THAN MAVMOS AND STICK CLOSE ON LOWS. A RIDGE OF HIGH PRESSURE WILL THEN BUILD UP ACROSS CENTRAL INDIANA ON SUNDAY AS WARM AIR ADVECTION BEGINS AS THE DOME OF COLD AIR BEGINS TO DEPART TO THE EAST. STRONG SOUTHERLY FLOW WILL SET UP BY SUNDAY EVENING AS HIGH PRESSURE SETTLES ACROSS APPALACHIA AND A LOW DEVELOPS OVER THE WESTERN PLAINS STATES. WILL AIM FOR A DRY SUNDAY ALONG WITH TEMPS WARMER THAN MEXMOS. && .LONG TERM /MONDAY THROUGH THURSDAY/... LONGER RANGE MODEL DATA SUGGEST A PROGRESSIVE AND POTENTIALLY ENERGETIC PATTERN ACROSS THE COUNTRY WITH JET STREAM WINDS PROGGED IN THE 120-170KT RANGE THROUGHOUT MOST OF THE EXTENDED PERIOD. ENSEMBLES ARE KEYING ON TWO SYSTEMS...ONE PASSING THROUGH IN THE EARLY TO MIDDLE PARTS OF NEXT WEEK AND ANOTHER POSSIBLY AROUND THURSDAY. AT THIS TIME...THE FIRST SYSTEM LOOKS TO BE THE STRONGER OF THE TWO. WILL CONTINUE WITH POPS FROM MONDAY THROUGH TUESDAY NIGHT...WITH THE HIGHEST POPS MONDAY NIGHT. JUST ABOUT ALL OF THE ENSEMBLES TAKE THE SURFACE LOW NORTH OF THE LOCAL AREA...SO THIS LOOKS TO BE MAINLY A RAIN EVENT...WITH SOME POTENTIAL FOR LIGHT SNOW NEAR THE END OF THE EVENT. SYSTEM ON THURSDAY LOOKS TO BE MORE OF A CLIPPER TYPE...AS MAIN UPPER TROUGH AXIS IS PROGGED TO BE NEAR THE EAST COAST. WILL GO WITH CHANCE POPS FOR LIGHT SNOW AT THAT TIME. && .AVIATION /DISCUSSION FOR THE 122100Z TAF UPDATES/... THE HEAVIER SNOW HAS ENDED FOR NOW...SO RAISED THE VISIBILITIES TO P6SM WITH FLURRIES AND RAISED CEILINGS TO MVFR. GUSTS ARE ALSO PICKING UP ON CUE SO TWEAKED WITH WINDS JUST A BIT. PREVIOUS DISCUSSION FOLLOWS... RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND 121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS. SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL. LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE WIDESPREAD LOW MVFR. WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30 KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE WESTERLY. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031- 035>049-051>057-060>065-067>072. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM....JAS AVIATION...CP/JAS/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
210 PM EST THU JAN 12 2012 .UPDATE... THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW && .SYNOPSIS...A STRONG COLD FRONT WILL SWEEP ACROSS CENTRAL INDIANA...USHERING AN ARCTIC AIRMASS INTO CENTRAL INDIANA FOR THE NEXT FEW DAYS. AN UPPER LEVEL LOW PRESSURE SYSTEM WILL EXIT THE STATE TONIGHT...HOWEVER...MOISTURE WRAPPING AROUND THE LOW WILL LIKELY RESULT IN SCATTERED SNOW SHOWERS...PARTICULARLY THIS EVENING. THE STRONG LOW WILL LINGER ACROSS THE NORTHEAST UNITED STATE ON FRIDAY...PROVIDING A COLD...ARCTIC FLOW OF AIR TO CENTRAL INDIANA. A FEW SNOW SHOWERS CANNOT BE RULED OUT ON FRIDAY. A QUICK MOVING RIDGE OF HIGH PRESSURE WILL PUSH ACROSS THE STATE FRIDAY NIGHT AND SATURDAY...PROVIDING MORE COLD...CLOUDY...BUT DRY WEATHER. ANOTHER UPPER LEVEL DISTURBANCE WILL PUSH INTO THE STATE FROM THE NORTHWEST ON SATURDAY NIGHT AND SUNDAY...AND THIS MAY PROVIDE ANOTHER BRIEF ROUND OF SNOW SHOWERS. THE COLD AIR IS EXPECTED TO EXIT EARLY NEXT WORK WEEK AS THE FLOW ALOFT BECOMES MORE WESTERLY USHERING MILD PACIFIC AIR BACK TO THE OHIO VALLEY. && .NEAR TERM /TONIGHT/... SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHERN ONTARIO EARLY THIS AFTERNOON AND A COLD FRONT STRETCHED SOUTH ACROSS WESTERN OHIO. MUCH COLDER AIR WAS FOUND ACROSS CENTRAL ILLINOIS AND WESTERN CENTRAL INDIANA WHERE TEMPERATURES WERE IN THE TEENS. WATER VAPOR IMAGERY INDICATE THE UPPER LOW OVER SE MISSOURI...DRIVING EASTWARD. RADAR TRENDS SHOW MUCH DRIER AIR WRAPPING IN TO THE SYSTEM FROM THE SOUTHWEST. MODELS AGREE THAT THE UPPER SYSTEM WILL PUSH ACROSS THE STATE TONIGHT...HOWEVER BEST FORCING IS LOST AFTER 06Z. POTENTIAL VORTICITY MUCH DRIER ARRIVING ALONG WITH SUBSIDENCE AFTER 06Z...HOWEVER FORECAST SOUNDINGS CONTINUE TO SUGGEST DEEP SATURATION. ALSO 850MB POTENTIAL TEMPERATURE SURFACE SHOWS A WEAK TROWAL WORKING ACROSS THE STATE...BUT EXITING AFTER 06Z. THUS WILL KEEP POPS GOING INTO THE EVENING HOURS AS FORCING WILL BE FAVORABLE...HOWEVER WILL TAPER POPS OFF AFTER 06Z AS BEST DYNAMIC SHIFT WELL TO THE NORTHEAST. GIVEN THE DRY AIR WORKING INTO THE AREA ALONG WITH THE FORCING ENDING BY 06Z...FEEL THAT SNOW AMOUNTS ARE MORE LIKELY TO END UP AT THE LOWER END OF THE ADVISORY CRITERIA. AS FOR TEMPS WILL TREND COOLER THAN MAVMOS GIVEN THE STRONG COLD AIR ADVECTION. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... MODELS REMAIN IN PRETTY GOOD OVERALL AGREEMENT DURING THIS PERIOD AND WILL USE A BLEND. BROAD CYCLONIC FLOW WILL REMAIN IN PLACE ON FRIDAY AS THE UPPER LOW DEPARTS AND FORECAST SOUNDINGS INDICATE DEEP SATURATION BUT MINIMAL FORCING THROUGH 18Z. SOUNDINGS BEGIN TO DRY OUT AFTER 18Z AS THE COLD ARCTIC AIR MASS BEGINS TO SETTLE IN. THUS WILL CONTINUE LOW CHANCE POPS DURING THE MORNING HOURS...BUT TAPER OFF TO A DRY FORECAST IN THE AFTERNOON AS DRIER AIR ARRIVES. WILL TREND COLDER THAN MAVMOS FOR HIGHS. COLD NORTHWEST FLOW WILL PERSIST ALOFT ON FRIDAY NIGHT AND ANOTHER WEAK DISTURBANCE WILL PUSH ACROSS THE STATE. HOWEVER MOISTURE IS LIMITED AND NO PRECIP WILL BE EXPECTED. FURTHERMORE WITH A FRESH SNOW COVER AND 850MB TEMPS THAT HAVE FALLEN TO NEAR -11C...WILL TREND LOWS COLDER THAN MAVMOS. ANOTHER STRONGER UPPER DISTURBANCE WILL PUSH INTO THE AREA ON SATURDAY AND SATURDAY NIGHT. GFS IS MUCH DRIER THAN THE NAM. GIVEN THE EXPECTED FORCING...FEEL THAT THE NAM HANDLES THE SITUATION HERE AND LOW POPS APPEAR NEEDED. WITH COLD AIR IN PLACE PRECIP TYPE WILL BE SNOW AS THIS CLIPPER MOVES THROUGH. AGAIN GIVEN THE EXPECTED CLOUDS WILL TREND HIGHS ON SATURDAY COLDER THAN MAVMOS AND STICK CLOSE ON LOWS. A RIDGE OF HIGH PRESSURE WILL THEN BUILD UP ACROSS CENTRAL INDIANA ON SUNDAY AS WARM AIR ADVECTION BEGINS AS THE DOME OF COLD AIR BEGINS TO DEPART TO THE EAST. STRONG SOUTHERLY FLOW WILL SET UP BY SUNDAY EVENING AS HIGH PRESSURE SETTLES ACROSS APPALACHIA AND A LOW DEVELOPS OVER THE WESTERN PLAINS STATES. WILL AIM FOR A DRY SUNDAY ALONG WITH TEMPS WARMER THAN MEXMOS. && .LONG TERM /MONDAY THROUGH THURSDAY/... LONGER RANGE MODEL DATA SUGGEST A PROGRESSIVE AND POTENTIALLY ENERGETIC PATTERN ACROSS THE COUNTRY WITH JET STREAM WINDS PROGGED IN THE 120-170KT RANGE THROUGHOUT MOST OF THE EXTENDED PERIOD. ENSEMBLES ARE KEYING ON TWO SYSTEMS...ONE PASSING THROUGH IN THE EARLY TO MIDDLE PARTS OF NEXT WEEK AND ANOTHER POSSIBLY AROUND THURSDAY. AT THIS TIME...THE FIRST SYSTEM LOOKS TO BE THE STRONGER OF THE TWO. WILL CONTINUE WITH POPS FROM MONDAY THROUGH TUESDAY NIGHT...WITH THE HIGHEST POPS MONDAY NIGHT. JUST ABOUT ALL OF THE ENSEMBLES TAKE THE SURFACE LOW NORTH OF THE LOCAL AREA...SO THIS LOOKS TO BE MAINLY A RAIN EVENT...WITH SOME POTENTIAL FOR LIGHT SNOW NEAR THE END OF THE EVENT. SYSTEM ON THURSDAY LOOKS TO BE MORE OF A CLIPPER TYPE...AS MAIN UPPER TROUGH AXIS IS PROGGED TO BE NEAR THE EAST COAST. WILL GO WITH CHANCE POPS FOR LIGHT SNOW AT THAT TIME. && .AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/... RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND 121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS. SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL. LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE WIDESPREAD LOW MVFR. WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30 KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE WESTERLY. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031- 035>049-051>057-060>065-067>072. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM....JAS AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1134 AM EST THU JAN 12 2012 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY. IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS OUR REGION BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THIS AFTERNOON/... RADAR TRENDS INDICATE SNOW SHOWERS PUSHING ACROSS THE FORECAST AREA AHEAD OF THE ARCTIC FRONT. VERY COLD AIR...IN THE TEENS...WAS FOUND BEHIND THE FRONT AND IS EXPECTED TO ADVECT ACROSS THE FORECAST AREA THIS AFTERNOON. HAVE TRENDED HOURLY TEMPERATURE GRIDS MUCH LOWER THIS AFTERNOON REFLECTING THIS CHANGE. ALSO HAVE RAISED POPS TO CATEGORICAL BASED UPON RECENT RADAR TRENDS. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM 1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE 70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO. ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL LIMIT SNOWFALL. WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z. COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO REASON NOT TO FOLLOW THIS TREND. WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD. && .AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/... RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND 121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS. SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL. LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE WIDESPREAD LOW MVFR. WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30 KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE WESTERLY. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031- 035>049-051>057-060>065-067>072. && $$ SYNOPSIS...JH NEAR TERM...PUMA SHORT TERM...JH LONG TERM....CP AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
938 AM EST THU JAN 12 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY. IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS OUR REGION BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... MAIN FOCUS WILL BE WORSENING WEATHER CONDITIONS LATER TODAY AND WHETHER TO MAKE ANY CHANGES TO PREVIOUS PACKAGE. THE RAIN FROM YESTERDAYS SYSTEM HAD MOVED OUT AND SNOW WAS BEGINNING TO SPREAD INTO INTO WESTERN ILLINOIS. THE RAPID REFRESH BRINGS SNOW INTO WESTERN INDIANA BY 15Z AND MOST OTHER AREAS MIDDAY OR LATER. MOST OF THE SIGNIFICANT ACCUMULATIONS WILL BE THIS AFTERNOON AND WINDS WILL BE INCREASING THEN TOO. WILL BEGIN WINTER WEATHER ADVISORY ACROSS OUR FORECAST AREA AROUND NOON AND CONTINUE IT TO 1 PM TOMORROW. THE NAM AND CANADIAN MODELS INDICATE SLIGHTLY LOWER PRECIP AMOUNTS ACROSS OUR SOUTHEAST. A LITTLE MORE THAN A HALF INCH. ON THE OTHER HAND...THE EUROPEAN AND GFS MODELS ARE LITTLE CHANGED FROM PREVIOUS RUNS. WILL SLOWER AMOUNTS SLIGHTLY ACROSS OUR SOUTHEAST HALF TODAY...BUT STILL ENOUGH TO SUPPORT THE WINTER WEATHER ADVISORY AS WINDS INCREASE CAUSING BLOWING AND DRIFTING SNOW BY TONIGHT. AS FAR AS TEMPERATURES...WENT WITH A BLEND OF SREF 2 METER TEMPERATURES AND MAV/MET HOURLY NUMBERS. TEMPERATURES WILL FALL INTO THE MID 20S MOST AREAS BY THIS AFTERNOON. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM 1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE 70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO. ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL LIMIT SNOWFALL. WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z. COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO REASON NOT TO FOLLOW THIS TREND. WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD. && .AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/... RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND 121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS. SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL. LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE WIDESPREAD LOW MVFR. WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30 KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE WESTERLY. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR INZ021-028>031-035>049-051>057-060>065-067>072. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....CP AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
601 AM EST THU JAN 12 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY. IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS OUR REGION BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... MAIN FOCUS WILL BE WORSENING WEATHER CONDITIONS LATER TODAY AND WHETHER TO MAKE ANY CHANGES TO PREVIOUS PACKAGE. THE RAIN FROM YESTERDAYS SYSTEM HAD MOVED OUT AND SNOW WAS BEGINNING TO SPREAD INTO INTO WESTERN ILLINOIS. THE RAPID REFRESH BRINGS SNOW INTO WESTERN INDIANA BY 15Z AND MOST OTHER AREAS MIDDAY OR LATER. MOST OF THE SIGNIFICANT ACCUMULATIONS WILL BE THIS AFTERNOON AND WINDS WILL BE INCREASING THEN TOO. WILL BEGIN WINTER WEATHER ADVISORY ACROSS OUR FORECAST AREA AROUND NOON AND CONTINUE IT TO 1 PM TOMORROW. THE NAM AND CANADIAN MODELS INDICATE SLIGHTLY LOWER PRECIP AMOUNTS ACROSS OUR SOUTHEAST. A LITTLE MORE THAN A HALF INCH. ON THE OTHER HAND...THE EUROPEAN AND GFS MODELS ARE LITTLE CHANGED FROM PREVIOUS RUNS. WILL SLOWER AMOUNTS SLIGHTLY ACROSS OUR SOUTHEAST HALF TODAY...BUT STILL ENOUGH TO SUPPORT THE WINTER WEATHER ADVISORY AS WINDS INCREASE CAUSING BLOWING AND DRIFTING SNOW BY TONIGHT. AS FAR AS TEMPERATURES...WENT WITH A BLEND OF SREF 2 METER TEMPERATURES AND MAV/MET HOURLY NUMBERS. TEMPERATURES WILL FALL INTO THE MID 20S MOST AREAS BY THIS AFTERNOON. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM 1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE 70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO. ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL LIMIT SNOWFALL. WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z. COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO REASON NOT TO FOLLOW THIS TREND. WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD. && .AVIATION /DISCUSSION FOR 121200Z TAF ISSUANCE/... SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL. LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE WIDESPREAD LOW MVFR. WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30 KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE WESTERLY. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR INZ021-028>031-035>049-051>057-060>065-067>072. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....CP AVIATION...CP
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
538 PM CST FRI JAN 13 2012 .AVIATION... MVFR CONDITIONS WILL CONTINUE THROUGH EARLY EVENING WITH INTERMITTENT LIGHT SNOW. THE -SN IS EXPECTED TO COMPLETELY DISSIPATE BY 03Z. VFR WX WILL THEN BE SEEN AS HIGH PRESSURE MOVES ACROSS EASTERN IOWA AND ILLINOIS OVERNIGHT. THE NEXT SYSTEM APPROACHES FROM THE NORTHERN PLAINS SATURDAY MORNING...WITH -SN EXPECTED TO DEVELOP BY MID TO LATE MORNING AT KCID/KBRL. 12Z- 18Z/14 MVFR CONDITIONS COULD DEVELOP AGAIN AT ALL TAF SITES AS -SN BECOMES MORE WIDESPREAD. ..ERVIN.. && .PREV DISCUSSION... /ISSUED 327 PM CST FRI JAN 13 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS AN EXTRATROPICAL CYCLONE IN SOUTHEAST CANADA WITH NUMEROUS TROFS FROM THE TENNESSEE VALLEY BACK INTO THE UPPER MIDWEST. RADAR TRENDS THROUGH MID AFTERNOON CONTINUE TO SHOW PLENTY OF FLURRIES AND LIGHT SNOW OVER THE MID MISSISSIPPI VALLEY. CLEARING UNDER THE CYCLONIC FLOW WAS MAKING SLOW BUT STEADY PROGRESS EASTWARD. 18Z SFC ANALYSIS HAS A COLD FRONT FROM THE EASTERN GREAT LAKES BACK INTO NORTHEAST ILLINOIS WITH A HIGH PRESSURE RIDGE FROM MINNESOTA INTO EASTERN TEXAS. A CHINOOK WARM FRONT WAS OVER THE EASTERN PARTS OF THE DAKOTAS AND NEBRASKA. A WARM FRONT ASSOCIATED WITH THE NEXT CLIPPER SYSTEM WAS MOVING OUT OF THE NORTHERN ROCKIES. DEW POINTS UNDER THE HIGH PRESSURE RIDGE WERE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. OTHERWISE DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE MIDWEST AND PLAINS. SHORT TERM...TONIGHT AND SATURDAY... LIGHT SNOW WILL CONTINUE THROUGH LATE AFTERNOON BUT WILL TAPER TO FLURRIES ONCE SUNSET OCCURS. RUC TRENDS CONTINUE TO SHOW WEAK F VECTOR CONVERGENCE AND WEAK FRONTOGENETICAL FORCING WILL REMAIN ACROSS THE AREA INTO THE EARLY EVENING. THAT COMBINED WITH THE SHALLOW ARCTIC AIR MASS AND A VORT MAX MOVING THROUGH THE CWFA WILL ALLOW FLURRIES TO PERSIST THROUGH MID EVENING. CLEARING WILL OCCUR FROM WEST TO EAST DURING THE EVENING AND OVERNIGHT HOURS. TEMPERATURES SHOULD DROP QUICKLY ONCE CLEARING OCCURS DUE TO THE SNOW COVER AND LIGHT WINDS. AFTER MIDNIGHT...WAA CLOUDS FROM THE APPROACHING CLIPPER SYSTEM WILL MOVE INTO THE AREA AND LIKELY ALLOW TEMPERATURES TO BOTTOM OUT AND SLOWLY RISE. AFTER 3 AM...ALL MODELS SHOW F VECTOR CONVERGENCE DEVELOPING AGAIN WITH COLLAPSING CONDENSATION PRESSURE DEFICITS ALONG WITH AN INCREASE IN FRONTOGENETICAL FORCING. MOISTURE WITH THIS CLIPPER SYSTEM IS LIMITED BUT FLURRIES AND LIGHT SNOW SHOULD BREAK OUT PRIOR TO DAWN GENERALLY WEST OF A KIIB TO KPPQ LINE. SCHC/CHC POPS WERE DONE DUE TO THE LIMITED MOISTURE BUT MAY NEED TO BE RAISED IN THE EXTREME WEST AND SOUTHWEST PARTS OF THE CWFA. THE WAA PRECIPITATION WING OF THE CLIPPER SYSTEM WILL MOVE ACROSS THE WESTERN HALF OR TWO THIRDS OF THE CWFA SATURDAY MORNING. CONDENSATION PRESSURE DEFICITS REMAIN LOW AND THERE IS F VECTOR CONVERGENCE WITH SOME FORCING. DURING THE AFTERNOON THE COLD CONVEYOR BELT PRECIPITATION FROM THE CLIPPER SYSTEM WILL OVERSPREAD THE ENTIRE AREA BEFORE ENDING FROM THE WEST LATE IN THE AFTERNOON. AS FOR AMOUNTS...A DUSTING OF ACCUMULATION IS POSSIBLE PRIOR TO SUNRISE IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA. ACCUMULATIONS DURING THE DAY SATURDAY SHOULD RANGE FROM A DUSTING TO ONE HALF INCH. IT IS CONCEIVABLE THAT ACCUMULATIONS APPROACHING AN INCH MAY OCCUR OVER THE SOUTHWEST THIRD TO HALF OF THE CWFA. ..08.. LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY... ACTIVE/UNSETTLED PATTERN TO PERSIST THROUGH THE PERIOD WITH MANY FCST CHALLENGES. MAIN STORM SYSTEM THAT BEARS CONSIDERABLE WATCHING IS IN MON-TUE TIME-FRAME. THIS STORM LOOKS TO BRING WINTRY MIX OF PCPN WITH POTENTIAL FOR HEADLINES. SAT NGT... SOME RESIDUAL WEAK LIFT LINGERS INTO THE EVE ACROSS THE NORTH AS CLIPPER DEPARTS AND WARM FRONT PUSHES THROUGH. NAM AND GFS BUFR SOUNDINGS SHOW LOSS OF ICE INTRODUCTION WHICH WOULD SUPPORT DRIZZLE OR FREEZING DRIZZLE. CONCERNS THOUGH THESE MODELS MAY BE OVERDONE WITH EXTENT OF LOW LEVEL MOISTURE ... A TYPICAL BIAS ESPECIALLY WITH NAM... ESPECIALLY GIVEN NO SNOW MELT. GIVEN UNCERTAINTIES AND WITH ANY PCPN JUST TRACE AMOUNTS HAVE LEFT OUT ANY MENTION ATTIM. MAY SEE TEMPS STEADY OR RISING OVRNGT ESPECIALLY SOUTH WITH ONSET OF LOW LEVEL WARM ADVECTION. SUN-SUN NGT... NEXT ARCTIC FRONT TO EMERGE INTO THE PLAINS AND EXPECTED TO PUSH THROUGH IA AND POSSIBLY BISECTING 12Z MON PER NAM/GFS. HI-RES ECMWF SLOWER BUT 12Z RUN IS SLIGHTLY FASTER AND MAY BE TRENDING TOWARD NAM/GFS. DEEPER MOISTURE RETURNS LATE FOR POSSIBLY SOME VERY LIGHT RAIN OR DRIZZLE AFTER MIDNIGHT... OR VERY LIGHT FREEZING RAIN/DRIZZLE IN SOME AREAS DEPENDING ON SFC TEMPS WITH NW CWA MOST SUSCEPTIBLE IT APPEARS ATTIM BUT THIS DEPENDENT ON FRONTAL TIMING. MOST IF NOT ALL OF AREA SHOULD GET ABOVE FREEZING WITH 40S WIDESPREAD ACROSS THE SW CWA ON GUSTY SOUTHERLY WINDS. MON-TUE... STRONG BAROCLINICITY AND COUPLED JET STRUCTURE SUPPORT CYCLOGENESIS ALONG ARCTIC FRONT... WITH CONSIDERABLE MODEL SPREAD ON MAGNITUDE/TRACK/TIMING... AND GIVEN HIGHLY DYNAMICAL ENVIRONMENT EXPECT CONTINUED CHANGES IN MODELS NEXT DAY OR TWO. GFS AND HI-RES ECMWF HAVE TRENDED DEEPER AND SLOWER... AND MAY CONTINUE TO SEE THIS TREND. BOTTOM LINE IS MOISTURE AND FORCING SUPPORTS MODERATE QPF EVENT NOT TOO DISSIMILAR FROM THIS MOST RECENT EVENT. DEPENDING ON FRONT AND SFC LOW LOCATIONS PCPN TYPES COULD VARY OR TRANSITION FROM RAIN TO FREEZING RAIN...SLEET AND SNOW ACROSS CWA. THEREFORE... WITH THE WINTRY MIXTURE THIS SYSTEM WILL BEAR CONSIDERABLE WATCHING IN THE DAYS AHEAD. POPS ARE IN MOD/HIGH CHC CATEGORY FOR NOW GIVEN UNCERTAINTY WITH TRACK. IN ADDITION MAY SEE FOG MON WITH AREAS OF DENSE FOG AHEAD OF SFC LOW WITHIN LOW LEVEL MOISTURE CONVERGENCE. WED-FRI... MUCH COLDER WITH ANOTHER ARCTIC FRONT SUGGESTED TO ARRIVE WED THAT MAY NEED POPS IN LATER FCSTS. FOR NOW THOUGH HAVE CHC POPS THU-FRI AS ENERGY RIPPLES ALONG LOW-MID LEVEL BAROCLINIC ZONE. WINTER HAS FINALLY ARRIVED. ..05.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
339 PM CST THU JAN 12 2012 .SYNOPSIS... 12Z UA ANALYSIS HAD AN 850MB LOW ALONG THE IA/WI BORDER WITH ANOTHER IN SOUTHEAST LOWER MICHIGAN. A TROF EXTENDED SOUTH FROM THE IA/WI LOW INTO SOUTHEAST MISSOURI. RADAR TRENDS THROUGH EARLY AFTERNOON SHOW AN UPPER LEVEL FEATURE THAT IS PIVOTING A DEFORMATION ZONE ACROSS EASTERN IOWA AND NORTHERN ILLINOIS. 18Z SFC ANALYSIS HAS AN OCCLUDED LOW BETWEEN KGRR AND KAZO AND ANOTHER ON THE SOUTHERN EDGE OF LAKE HURON. THE POLAR FRONT EXTENDED SOUTH FROM THE OCCLUDED LOW INTO CENTRAL ALABAMA. SEVERAL WEAK TROFS RAN FROM SOUTHERN LAKE MICHIGAN INTO MISSOURI BACK UP INTO SOUTHERN WISCONSIN AND IOWA. DEW POINTS WERE IN THE TEENS AND 20S FROM THE WESTERN GREAT LAKES AND LOWER MISSISSIPPI VALLEY TO THE SINGLE DIGITS ABOVE AND BELOW ZERO ACROSS THE PLAINS. && .SHORT TERM...TONIGHT... RADAR AND WATER VAPOR ARE QUITE INTERESTING. A VORT MAX IS ROTATING AROUND THE UPPER LOW IN SOUTHERN ILLINOIS WHICH IS HELPING TO PIVOT THE DEFORMATION ZONE ACROSS THE CWFA. THE END POINT OF THE PIVOT IS SLOWLY DRIFTING TO THE EAST SOUTHEAST AS THE UPPER LOW MOVES INTO THE OHIO VALLEY PER RUC TRENDS. THUS LIGHT TO MODERATE SNOW WITH BURSTS OF HEAVY SNOW WILL CONTINUE THROUGH 6 PM. THE RUC SHOWS ANOTHER VORT MAX ROTATING FROM NORTHEAST ILLINOIS BACK INTO EASTERN IOWA DURING THE EARLY EVENING. THIS FEATURE SHOULD ALLOW THE SNOW TO MAINTAIN ITSELF THROUGH 9 PM. AFTER 9 PM THE FORCING OVER THE WESTERN THIRD OF THE CWFA WEAKENS RAPIDLY SO THE SNOW THERE SHOULD QUICKLY TAPER TO FLURRIES. THE RUC TRENDS BLEND IN NICELY WITH THE WRF/GFS TRENDS INDICATING THE OVERALL FORCING WEAKENING RAPIDLY AFTER MIDNIGHT ACROSS THE EASTERN TWO THIRDS OF THE CWFA. THUS SNOW WILL TAPER TO FLURRIES ACROSS THE REMAINDER OF THE CWFA AFTER MIDNIGHT WITH ALL BUT THE FAR EASTERN PARTS OF THE CWFA SEEING THE FLURRIES END PRIOR TO SUNRISE. THE CURRENT HEADLINES WILL REMAIN AS IS FOR NOW. IF THE TRENDS FROM THE RUC AND OTHER MODELS ARE CORRECT...THE POSSIBILITY DOES EXIST THAT THE HEADLINES MAY BE CANCELLED EARLIER THAN THE CURRENT END TIMES. NOW FOR AMOUNTS. ADDITIONAL SNOWFALL THIS EVENING SHOULD RANGE FROM A DUSTING IN THE FAR WESTERN PARTS OF THE CWFA TO JUST OVER AN INCH IN THE EASTERN THIRD OF THE CWFA. MOST OF THIS ADDITIONAL SNOWFALL WILL OCCUR BETWEEN 6 AND 8 PM. AFTER MIDNIGHT...AN ADDITIONAL DUSTING MAY OCCUR IN THE EASTERN THIRD OF THE CWFA WHERE LIGHT SNOW WILL LINGER THE LONGEST. SO...STORM TOTALS SHOULD BE A GENERAL 3 TO 6 INCHES ACROSS THE AREA. AN AREA 20 MILES EITHER SIDE OF A LINE CENTERED FROM CEDAR RAPIDS TO ROUGHLY STERLING SHOULD SEE 5 TO 7 INCHES WITH LOCALLY HIGHER AMOUNTS. ..08.. .LONG TERM...FRIDAY THROUGH NEXT THURSDAY... ACTIVE PATTERN TO PREVAIL THROUGH THE PERIOD. FRI-FRI NGT...ADDITIONAL ENERGY DIVING DOWN BACKSIDE OF DEPARTING SYSTEM WILL KEEP CLOUDS AND POSSIBLY FEW FLURRIES AROUND FOR A TIME FRI AM. THEN EXPECT SOME DECREASE IN CLOUDS FRI AFTN WITH SUBSIDENCE. BRISK NW WINDS CONTINUE AND WITH CLOUDS SLOW TO DECREASE AND FRESH SNOW HAVE SIDED AT OR BELOW COLD SIDE OF GUIDANCE FOR HIGHS. NEXT CLIPPER SYSTEM WHICH SEEN ON WATER VAPOR JUST COMING INTO BC APPEARS TO BE A LITTLE STRONGER THAT PROGGED. THIS ENERGY TO HEAD SE FRI NGT AND WILL SEE INCREASE IN CLOUDS WITH WARM ADVECTION WING WITH CHC OF -SN/--SN LATE PORTIONS OF W/NW. LIGHT WINDS AND PARTIAL CLEARING FOR TIME FRI EVE SHOULD AID IN QUICK DROP TO NEAR OR BELOW GUIDANCE MINS BEFORE TEMPS STEADY OR RISE WITH CLOUDS AND LLVL WARM ADVECTION OVRNGT. SAT-SAT NGT...CLIPPER SYSTEM TO PASS DURING DAY WITH STILL PLENTY OF SPREAD ON TRACK AND STRENGTH. ENHANCED BAROCLINICITY FROM EVOLVING SNOW FIELD MAY PLAY ROLE... AND GIVEN THIS AND WHAT LOOKS LIKE STRONGER WAVE WONDER IF TRACK AND POPS MAY NEED TO BE ADJUSTED SWWD. LIMITED MOISTURE AND SO COULD END UP MOSTLY FLURRIES WITH AREAS OF -SN WITH ANY ACCUMS MINOR AT OR BELOW 1 INCH. AT LEAST PARTIAL CLEARING SAT NGT IN WAKE WITH LIGHT WINDS AND HAVE LOWERED MINS TO BELOW GUIDANCE... BUT RETURN FLOW KICKS IN LATE THAT MAY SEE TEMPS CLIMB OVRNGT. SUN-SUN NGT... DRY WITH MODERATING TEMPS AS WARM ADVECTION STRENGTHENS ON GUSTY SLY WINDS... WITH HEIGHTS BUILDING ALOFT. FRONT MOVES INTO IA SUN NGT BUT SUGGESTION OF PCPN STAYING SOUTH OF CWA ACROSS PORTIONS OF MO SWD WITHIN DEEPER LLVL MOISTURE RETURN. MON-TUE... NEXT FRONT TO PASS WITH ENERGY AND BAROCLINICITY FAVORING SFC LOW DEVELOPMENT ALONG FRONT PASSING NEAR REGION THAT MAY REQUIRE POPS BEING RAISED. THERMAL PARAMETERS SUPPORT MAINLY RAIN MON BUT AS FRONT SAGS ACROSS CWA MON NGT AND COLDER AIR MOVES IN COULD SEE MIX THEN CHANGE TO SNOW WITH ANY RESIDUAL MOISTURE ON BACKSIDE LINGERING INTO TUE. ANY SNOW ACCUMS WOULD APPEAR TO BE LIGHT ATTIM. WED-THU...MUCH COLDER WITH CHC OF SNOW LATE PD WITH NEXT BOUT OF ENERGY. ..05.. && .AVIATION... IFR TO LIFR CONDITIONS WITH SNOW WILL CONTINUE THROUGH 02Z/13. AFT 02Z/13 CONDITIONS WILL SLOWLY IMPROVE TO MVFR. SNOW INTENSITY WILL DECREASE RAPIDLY AFT 02Z/13 AND TAPER TO FLURRIES BEFORE ENDING. VSBYS TO BECOME VFR AFT 06Z/13 WITH MVFR CIGS. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CLINTON-JACKSON- SCOTT. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON- BUCHANAN-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK- LEE-LOUISA-MUSCATINE-VAN BUREN-WASHINGTON. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CEDAR- DELAWARE-DUBUQUE-JONES-LINN. IL...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CARROLL-JO DAVIESS-ROCK ISLAND-STEPHENSON-WHITESIDE. WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR BUREAU-HANCOCK- HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-WARREN. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1147 AM CST THU JAN 12 2012 .UPDATE... BASED ON MORNING UA AND CURRENT TRENDS FROM THE RUC AND RADAR...A PORTION OF THE WINTER WEATHER ADVISORY HAS BEEN UPGRADED TO A WINTER STORM WARNING. WE WILL EASILY ACHIEVE A VERY HIGH END ADVISORY. HOWEVER...THE LACK OF SNOW SO FAR THIS SEASON COMBINED WITH THE WIND HAS RESULTED IN A LOWERING OF THE NORMAL THRESHOLDS. RUC TRENDS SHOW THE DEFORMATION ZONE SETTING UP OVER ROUGHLY THE NORTHERN CWFA AND WILL PIVOT TO THE NORTHEAST DURING THE AFTERNOON HOURS. THE WAA TOOL SUGGESTS THE STRONGEST FORCING ON THE WESTERN EDGE OF THE NEW WARNING AREA WILL MOVE EAST DURING THE AFTERNOON TOWARD THE MISSISSIPPI RIVER. SNOWFALL AMOUNTS HAVE BEEN RAISED BASED ON REPORTS SO FAR AND RUC/RADAR TRENDS. THE WINDS SO FAR HAVE NOT GOTTEN AS STRONG AS EXPECTED. MANY AREAS ARE ONLY 15 TO 25 MPH BUT MORE SITES ARE STARTING TO INCREASE TO 20 TO 30 MPH. GUSTS HAVE GENERALLY BEEN 30 MPH OR LESS SHOULD INCREASE TO 35 MPH DURING THE AFTERNOON HOURS. BASED ON RUC TRENDS...THE SNOW SHOULD RAPIDLY START SHUTTING DOWN AROUND MID EVENING WITH LINGERING FLURRIES AFTER MIDNIGHT. AS SUCH...THE EXPIRATION OF THE HEADLINES IN THE EASTERN CWFA HAVE BEEN PULLED BACK TO 3 AM. ..08.. && .AVIATION... SNOW WITH AREAS OF BLOWING SNOW AND IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE AFTN. SNOW WILL TAPER TO FLURRIES THEN END FROM NW TO SE THIS EVE WITH MVFR CIGS PREVAILING FOR MUCH OF THE REST OF PD. WINDS GENERALLY NW AT 10-20 KTS WITH HIGHER GUSTS AT TIMES. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CLINTON-JACKSON- SCOTT. WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON- BUCHANAN-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK- LEE-LOUISA-MUSCATINE-VAN BUREN-WASHINGTON. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CEDAR- DELAWARE-DUBUQUE-JONES-LINN. IL...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CARROLL-JO DAVIESS-ROCK ISLAND-STEPHENSON-WHITESIDE. WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR BUREAU-HANCOCK- HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-WARREN. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
648 PM MST FRI JAN 13 2012 .UPDATE... 646 PM MST FRI JAN 13 2012 LATEST RUC AND HRRR CATCHING INCOMING SURFACE TROUGH FROM THE NORTHWEST. THEY HAD THE STRENGTH/POSITION THE BEST WITH THE REMAINING MODEL OUTPUT NOT STRONG ENOUGH. SO INCREASED WIND SPEEDS OVER THE NORTHEAST PORTION OF THE AREA A LITTLE. ALSO BECAUSE OF THE STRONGER WINDS RAISED THE MINS SOME THAT SAME AREA AS WELL. OTHERWISE...JUST ADJUSTED HOURLY GRIDS. BULLER && .DISCUSSION... 208 PM MST FRI JAN 13 2012 TONIGHT...SHOULD SEE NORTHWEST WINDS OF 10 TO 20 MPH WINDS WITH HIGHER GUSTS THROUGH MIDNIGHT BEHIND A DEPARTING UPPER LEVEL DISTURBANCE. AFTER MIDNIGHT WINDS SUBSIDE A BIT INTO THE 10 MPH RANGE. OVERNIGHT LOWS WILL BE A BIT WARMER THEN THE PAST FEW NIGHTS AS WARM AIR ALOFT MOVES IN. WILL AIM FOR LOWS GENERALLY IN THE UPPER TEENS TO LOW 20S IN FAR EASTERN COLORADO...LOW TO MID 20S EAST OF THE CO/KS BORDER. THIS IS SEVERAL DEGREES WARMER THAN THE MAV AND MET MOS GUIDANCE. 007 SATURDAY-SUNDAY...H5 RIDGE CONTINUES TO BUILD EAST TOWARDS CWA...WITH DRY/STABLE AIR MASS IN PLACE THROUGH SUNDAY NIGHT. TEMPERATURES WILL CONTINUE TO MODERATE OVER THE NEXT FEW DAYS...WITH HIGH TEMPS IN THE 50S SATURDAY...AND MID/UPPER 50S ON SUNDAY. CONSIDERING TEMPS ALOFT SAT/SUN NIGHTS...BUMPED LOWS TO THE UPPER 20S. THIS IS ABOUT 5-10F ABOVE MOS GUIDANCE...HOWEVER CONSIDERING TEMPS ALOFT AND POSSIBLE SKY COVER SUN NIGHT...THIS MAY STILL BE TOO COOL. MONDAY-MONDAY NIGHT...TROUGH DEVELOPING OVER THE PACIFIC NW OVER THE WEEKEND WILL PROGRESS EAST ACROSS THE GREAT BASIN TOWARDS THE CWA MONDAY. GUIDANCE STILL DIFFERS BY ABOUT 6HR ON TIMING OF ASSOCIATED COLD FRONT MONDAY...HOWEVER OVERALL TREND HAS BEEN TO SPEED UP ARRIVAL...WITH FRONTAL PASSAGE LIKELY BY MIDDAY. PRECIP ASSOCIATED WITH LARGE SCALE ASCENT ALONG LEADING EDGE OF TROUGH AXIS LOOKS TO ARRIVE FROM THE NW LATE MONDAY AFTERNOON...QUICKLY MOVING EAST THROUGH THE EVENING HOURS. GUIDANCE IN GOOD AGREEMENT ON STABLE/DRY AIR QUICKLY MOVING IN AFTER 06Z...SO I TRENDED FORECAST IN THAT DIRECTION. I KEPT BEST CHANCES DURING THE EVENING IN THE NORTH...AND LEFT A SMALL AREA OF SLIGHT CHANCE POPS IN THE FAR EAST AFTER 06Z. CONSIDERING LIMITED MOISTURE AND QUICK NATURE OF THIS SYSTEM...ONLY ANTICIPATING LIGHT SNOW ACCUMULATIONS...ABOUT AN INCH OR LESS. TUESDAY-FRIDAY...REMAINING FORECAST LOOKS DRY WITH W/NW FLOW DEVELOPING ACROSS WESTERN CONUS...AND DRY/STABLE AIR MASS IN PLACE. BIGGEST QUESTION THROUGH THESE PERIODS WILL BE HOW QUICKLY SHALLOW COLD AIR MASS MODERATES...AND WHAT TEMPS WILL DO IN RESPONSE TO WEAK SHORTWAVE TROUGHS EMBEDDED WITHIN MEAN FLOW. FOR NOW EXPECT BELOW NORMAL TEMPS TUESDAY AND NEAR NORMAL TEMPS WEDNESDAY. GUIDANCE STILL INDICATING RISING H5 HEIGHTS H85 TEMPS TO ABOUT 10-12C BY FRIDAY...WHEN I KEPT FORECAST OF MID 50S IN THE WEST. THIS MAY END UP BEING TOO COOL CONSIDERING CONDITIONS ALOFT...HOWEVER THERE IS ENOUGH UNCERTAINTY IN REGARDS TO BOUNDARY LAYER DIFFERENCES TO KEEP ME FROM CHANGING TOO MUCH THIS FAR OUT. DR && .AVIATION... 440 PM MST FRI JAN 13 2012 FOR THE 00Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WIND FORECAST A LITTLE INTERESTING. EARLIER FORECAST HAD LIGHTER WINDS OCCURRING DURING THE NIGHT. BELIEVE THE WINDS WILL BE STRONGER...ESPECIALLY AT KMCK...BEGINNING NEAR 03Z AND CONTINUING THROUGH THE REST OF THE NIGHT. BASE THIS ON STRONG SHORTWAVE UPPER TROUGH MOVING ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY WHICH IS PUSHING A SURFACE TROUGH THROUGH AT THIS TIME. STRONG SUBSIDENCE SEEN ON SATELLITE AND DECENT GRADIENT OCCURRING BEHIND THE SYSTEM AS SHOWN BY WINDS UPSTREAM. HIGH RESOLUTION GUIDANCE WOULD SUPPORT SUSTAINED WINDS NEAR 15 KNOTS WITH GUSTS OCCURRING AT KMCK. SURFACE RIDGE MOVES IN LATE TONIGHT TO DECREASE THE WIND AND THEN CAUSE THE WINDS TO SHIFT TOWARD THE SOUTH DURING THE DAY. BULLER && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST WED JAN 11 2012 .AVIATION... FOR THE 06Z TAF ISSUANCE... GUSTY NORTH WINDS AT AROUND 20KTS WILL CONTINUE THROUGH AT LEAST 09Z AS A 700MB COLD POOL CROSSES SOUTHWEST KANSAS. THESE GUSTY WINDS ARE EXPECTED TO BRIEFLY SUBSIDE SLIGHTLY TOWARDS DAYBREAK BUT WILL THEN REBOUND BACK TO AROUND 25 KNOTS BY MID MORNING AS MIXING IMPROVES. AFTER 00Z FRIDAY THE WINDS WILL BEGIN TO DECREASE AS THE SUNSETS AND THE ATMOSPHERE DECOUPLES. OTHER THAN SOME MID LEVEL MOISTURE ACCOMPANYING THE COLD POOL EARLY THIS MORNING THE BUFR SOUNDINGS INDICATING VFR CONDITIONS THROUGH THURSDAY NIGHT. -RB && PREV DISCUSSION... /ISSUED 203 PM CST WED JAN 11 2012/ SYNOPSIS... 12Z RAOB PLOT ANALYSIS INDICATES A LARGE TROUGH PUSHING ACROSS THE ROCKIES AND INTO THE NORTHERN PLAINS. THIS FEATURE HAS USHERED IN A COLD FRONT EARLY THIS MORNING ACROSS SOUTHWEST KANSAS. AS OF 18Z, THIS FRONT IS STILL MOVING ACROSS OKLAHOMA. WINDS WERE STRONG BEHIND THE FRONT WITH MANY OBSERVATION SITES ACROSS WESTERN KANSAS REPORTING WINDS AROUND 30 KT. DISCUSSION... DAYS 1-2... TONIGHT: SHORT TERM FOCUS IS WINDS. HAVE UPDATED THE WIND ADVISORY FOR THE ENTIRE REGION AS AWOS SITES ACROSS FAR WESTERN KANSAS HAVE BEEN AT WIND ADVISORY CRITERIA EARLIER. HRRR AND NAM SHOW THAT WINDS WILL QUICKLY TAPER TOWARDS 6 PM CST. SECOND SHORT TERM FOCUS IS IF WE WILL SEE PRECIPITATION. THE NAM HAS VERY LIGHT QPF ACROSS CENTRAL KANSAS TONIGHT. HRRR ALSO INDICATES LIGHT COMPOSITE REFLECTIVITY FORECAST SO HAVE PUT 20 POPS ACROSS THE NORTHEAST/NORTH. ELSEWHERE, WILL KEEP AROUND 10 PERCENT WITH FLURRIES. THIS ACTIVITY WILL DIMINISH THIS EVENING. OVERNIGHT LOWS WILL BE ON THE COLD SIDE AS WINDS WEAKEN AND SKIES CLEAR. WINDS WILL NOT COMPLETELY CALM SO DID NOT GET TOO CARRIED AWAY WITH LOWS. THURSDAY/THURSDAY NIGHT: ANOTHER WINDY DAY LOOKS LIKELY ACROSS SOUTHWEST KANSAS TOMORROW. THIS IS IN ASSOCIATION WITH A TIGHT PRESSURE GRADIENT REMAINING OVER THE AREA. HAVE INCREASED WINDS IN THE GRIDS IN THE 20 TO 30 MPH RANGE BUT KEPT VALUES/GUSTS BELOW WIND ADVISORY CRITERIA. INSTEAD OF HAVING TWO WIND ADVISORIES OUT, WHICH COULD BE CONFUSING...I WILL LET THE MID SHIFT DECIDE IF WE NEED A WIND ADVISORY OR NOT. TOMORROWS HIGHS WILL BE IN THE 30S DEG F. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE TEENS DEG F. FRIDAY: KANSAS WILL BE IN NORTHWEST FLOW ALOFT WHICH FAVORS A DRY FORECAST. WILL KEEP POPS AT ZERO FRIDAY. COULD SEE SOME DOWNSLOPE WESTERLY WINDS FRIDAY SO HAVE WARMED HIGHS UP A BIT. 850 HPA TEMPERATURES WARM UP INTO THE LOWER SINGLE POSITIVE DIGITS DEG C, SO WE COULD SEE SOME MIXING TO 40S DEG F AT THE SURFACE. DAYS 3-7... THE MID TO UPPER-LEVEL FLOW WILL GRADUALLY TRANSITION FROM NORTHWESTERLY TO WEST-SOUTHWESTERLY FROM FRIDAY NIGHT INTO SUNDAY. THUS, SURFACE PRESSURES WILL FALL IN THE LEE OF THE ROCKIES ALONG WITH SOME WEAK LOW-LEVEL DOWNSLOPE FLOW. HIGH TEMPERATURES WILL MODIFY INTO THE MID 50S BY SATURDAY AND 55 TO 60 BY SUNDAY. A SHORTWAVE TROUGH WILL PROGRESS IN MAINLY ZONAL FLOW ACROSS THE CENTRAL AND NORTHERN PLAINS BY MONDAY AND MONDAY NIGHT. THIS WILL BRING SOME COLDER AIR INTO WESTERN KANSAS. SO AFTER A FAIRLY MILD DAY MONDAY (50S TO LOWER 60S) JUST IN ADVANCE OF THE FRONT, HIGHS WILL FALL INTO THE 30S OR LOWER 40S BY TUESDAY. NO PRECIPITATION CAN BE EXPECTED IN THIS ZONAL PATTERN. ANOTHER WARMING TREND IS EXPECTED BY JANUARY 18-19TH WITH HIGHS POSSIBLY REACHING TO NEAR 70F IN A GENERALLY ZONAL MID TO UPPER-LEVEL FLOW REGIME WITH LEE-TROUGHING AT LOW-LEVELS. HOWEVER, AS IS OFTEN THE CASE IN ZONAL REGIMES, THERE WILL BE A SHARP TEMPERATURE GRADIENT BETWEEN DOWNSLOPE FLOW OVER THE SOUTHERN AND CENTRAL PLAINS AND ARCTIC AIR OVER THE NORTHERN PLAINS OR SOUTHERN CANADA. ANY SHORTWAVE TROUGH TRAVERSING THE FLOW COULD RESULT IN ANOTHER SURGE OF COLD AIR. THE ECMWF IS ADVERTISING ANOTHER SUCH COOLDOWN BY JANUARY 20-21ST. NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH JANUARY 21ST. && .PRELIMINARY POINT TEMPS/POPS... DDC 12 35 14 46 / 10 0 0 0 GCK 11 35 12 47 / 10 0 0 0 EHA 11 37 15 48 / 10 0 0 0 LBL 11 36 15 48 / 10 0 0 0 HYS 11 33 11 46 / 10 0 0 0 P28 17 37 15 46 / 10 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAY ME
1243 PM EST THU JAN 12 2012 .SYNOPSIS... LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 1742Z UPDATE... HAVE ADDED A SMALL AREAS...COASTAL CUMBERLAND...LINCOLN AND SAGAHOC COUNTIES TO THE WARNING BASED ON CURRENT CONDS AND OBS. VERY LITTLE CHANGE TO THE SNOWFALL FORECAST...GOING FROM 3-6 INCHES TO 4-8 INCHES. RADAR SHOWING A GOOD BATCH OF +SN TO CROSS THAT REGION OVER THE NEXT HOUR OR TWO...DELIVERING 1" PER HOUR SNOWFALL RATES BEFORE THE PCPN TAPERS OFF. ANOTHER NICE BATCH OF HEAVY PCPN IS ROTATING NORTH FROM MASS AT THIS HOUR AS WELL. UPDATE... UPDATE WAS TO ADD WINTER STORM WARNINGS FOR SOUTH-CENTRAL NH PER LATEST OBS/REPORTS OF SNOWFALL IN THAT AREA. WRN NH WILL BE GETTING SHADDOWED SHORTLY...OTRW THEY WOULD HAVE BEEN INCLUDED AS WELL. TEMPS NOW WARMING ALONG THE COAST. CONSIDERED WARNINGS FOR PWM NORTH...HOWEVER...READINGS NOW IN THE UPPER 20S/LOWER 30S AND CLIMBING. A MIX IS NOW OCCURRING IN YORK COUNTY...AND IN THE MIDCOAST REGION. WOULDN`T BE SURPRIZED HOWEVER IF A FEW LOCATIONS BETWEEN PWM AND IWI RECEIVE LOCALLY 7" SNOWFALL. PREV DISC.. COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25 DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST. BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND. BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF MIXED PCPN BY A COUPLE HOURS THIS MORNING. TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO STATEMENTS AND/OR THE HWO SHORTLY. WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT. PREV DISC... LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER. FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING. WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR. LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT INTO FRIDAY. EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW. ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS IN THE AFTERNOON. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING IN MORE VERY CD AND BLUSTERY WX. GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS. STRONG GUSTY W THEN NW WINDS FRIDAY NGT. && .MARINE... SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND SETTLES OVER THE E COAST ON MONDAY. && .TIDES/COASTAL FLOODING... THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12 FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH TIDE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR MEZ007>009-012>014-018>022-024>026. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ023-027-028. COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MEZ023-024. NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR NHZ001>006-009-010. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NHZ007-008-013-014. COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR NHZ014. MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154. && $$ JC
AREA FORECAST DISCUSSION
NWS GRAY ME
1113 AM EST THU JAN 12 2012 .SYNOPSIS... LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... UPDATE WAS TO ADD WINTER STORM WARNINGS FOR SOUTH-CENTRAL NH PER LATEST OBS/REPORTS OF SNOWFALL IN THAT AREA. WRN NH WILL BE GETTING SHADDOWED SHORTLY...OTRW THEY WOULD HAVE BEEN INCLUDED AS WELL. TEMPS NOW WARMING ALONG THE COAST. CONSIDERED WARNINGS FOR PWM NORTH...HOWEVER...READINGS NOW IN THE UPPER 20S/LOWER 30S AND CLIMBING. A MIX IS NOW OCCURRING IN YORK COUNTY...AND IN THE MIDCOAST REGION. WOULDN`T BE SURPRIZED HOWEVER IF A FEW LOCATIONS BETWEEN PWM AND IWI RECEIVE LOCALLY 7" SNOWFALL. PREV DISC.. COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25 DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST. BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND. BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF MIXED PCPN BY A COUPLE HOURS THIS MORNING. TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO STATEMENTS AND/OR THE HWO SHORTLY. WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT. PREV DISC... LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER. FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING. WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR. LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT INTO FRIDAY. EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW. ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS IN THE AFTERNOON. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING IN MORE VERY CD AND BLUSTERY WX. GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS. STRONG GUSTY W THEN NW WINDS FRIDAY NGT. && .MARINE... SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND SETTLES OVER THE E COAST ON MONDAY. && .TIDES/COASTAL FLOODING... THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12 FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH TIDE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR MEZ007>009-012>014-018>022. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ023>028. COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MEZ023-024. NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR NHZ001>006-009-010. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NHZ007-008-013-014. COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR NHZ014. MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154. && $$ JC
AREA FORECAST DISCUSSION
NWS GRAY ME
900 AM EST THU JAN 12 2012 .SYNOPSIS... LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... ...BANDS OF HEAVY SNOW ABOUT TO ENTER MAINE AND NEW HAMPSHIRE QUICKLY FROM THE SOUTH... COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25 DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST. BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND. BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF MIXED PCPN BY A COUPLE HOURS THIS MORNING. TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO STATEMENTS AND/OR THE HWO SHORTLY. WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT. PREV DISC... LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER. FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING. WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR. LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT INTO FRIDAY. EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW. ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS IN THE AFTERNOON. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING IN MORE VERY CD AND BLUSTERY WX. GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS. STRONG GUSTY W THEN NW WINDS FRIDAY NGT. && .MARINE... SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT. LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND SETTLES OVER THE E COAST ON MONDAY. && .TIDES/COASTAL FLOODING... THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12 FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH TIDE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR MEZ007>009-012>014-018>022. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ023>028. NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR NHZ001>004-006. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NHZ005-007>010-013-014. MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154. && $$ JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
102 AM EST THU JAN 12 2012 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OVERNIGHT. LOW PRESSURE WILL APPROACH FROM THE SOUTHWEST THURSDAY AND TRACK THROUGH THE GULF OF MAINE THURSDAY NIGHT. ANOTHER LOW WILL MOVE NORTH THROUGH NEW ENGLAND FRIDAY. && .NEAR TERM /THROUGH TODAY/... UPDATE 0100L... FIRST ISSUE WAS TO RAISE OVERNIGHT INTO EARLY MORNING TEMPS DUE TO THICKENING CLOUD COVER. ALSO BROUGHT LOWER CLOUDS INTO DOWN EAST EARLY THIS MORNING AS COASTAL FRONT ORGANIZES WITH SIGNIFICANT TEMPERATURE GRADIENT ALONG COAST. WITH SOME COLD AIR DAMMING SETTING UP...LOOKED AT NORMALLY COLD RUC OUTPUT AND IT IS BRINGING IN WARM AIR RIGHT ALONG THE COAST AND A WARM LAYER ALOFT NEAR H850 EARLIER THAN OTHER MODELS. THIS MEANS LESS SNOW ACCUMULATION ALONG THE COAST AND NORTHWARD TO BGR DUE TO MIXED PRECIP. NEW EXPECTATION IS JUST OVER 4 INCHES AROUND BGR AND DROPPING OFF TO THE ONE TO THREE INCH RANGE IN THE ZONES 29 AND 30 WITH THE LOWEST VALUES ALONG THE COAST AND OUTER ISLANDS. THE BEST SNOW ACCUMULATIONS SHOULD BE ALONG THE HIGHER TERRAIN FROM JUST SOUTH OF GREENVILLE TOWARDS PATTEN AND SHIN POND WHERE COLDER AIR ALOFT AND UPSLOPE SHOULD MAXIMIZE SNOWFALL. UPDATE... HIGH PRESSURE WILL MOVE EAST OVERNIGHT WHILE LOW PRESSURE DEVELOPS ALONG THE MID ATLANTIC COAST. SKIES WILL BE CLOUDY ACROSS THE FORECAST AREA OVERNIGHT. LOW TEMPERATURES TONIGHT WILL GENERALLY RANGE FROM AROUND ZERO NORTH...TO 10 TO 15 DOWNEAST. HAVE UPDATED THE FORECAST TO ADJUST FOR CURRENT CONDITIONS ALONG WITH EXPECTED OVERNIGHT CLOUDS/TEMPERATURES. PREVIOUS DISCUSSION... THE LOW PRESSURE CENTER WITH THE SYSTEM THURSDAY WILL TRACK NORTHEAST RIGHT ALONG THE COAST IN THE AFTERNOON AND THURSDAY NIGHT. NEARLY ALL THE PRECIPITATION AND STRONGER WINDS WILL BE ON THE LEADING EDGE OF THE SURFACE LOW...AS THE UPPER LEVEL TROUGH AND DYNAMICS ARE EASILY OUTPACING THE SURFACE LOW. LOOK FOR SNOW TO BEGIN AROUND MIDDAY OVER SOUTHERN MAINE...SPREADING NORTH TO THE ENTIRE AREA BY LATE AFTERNOON OR EVENING. THE BEST DYNAMICS SUCH AS THE STRONGEST LIFT AND WARM ADVECTION WILL BE OVER SOUTHEAST HALF OF THE AREA WITH THE HIGHEST PRECIPITATION AMOUNTS THERE. HOWEVER...TEMPERATURES WILL BE ON THE RISE THROUGH THE EVENT WITH LOWERING SNOW RATIOS AND MIXED PRECIPITATION TOWARD THURSDAY EVENING PROBABLY KEEPING SNOW TOTALS AT FOUR TO SIX INCHES...JUST BELOW WARNING CRITERIA. FURTHER NORTH...EXPECT THE PRECIPITATION TYPE TO BE ALL SNOW NORTHWEST OF HOULTON FOR THIS FIRST ROUND LATE THURSDAY/THURSDAY NIGHT. THE PRECIPITATION WILL NOT BE AS HEAVY UP NORTH...SO EXPECT ABOUT THREE OR FOUR INCHES OF SNOW FOR THE SAINT JOHN VALLEY SOUTH TO CARIBOU AND PRESQUE ISLE. AGAIN...THIS IS JUST REFERRING TO THE FIRST ROUND THURSDAY/THURSDAY NIGHT. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... INTENSE LOW PRESSURE MOVES INTO THE GREAT LAKES THURSDAY EVENING WHILE SECONDARY LOW CENTER DEVELOPS IN THE GULF OF MAINE. THE SECONDARY LOW WILL MOVE THROUGH THE GULF OF MAINE THURSDAY NIGHT THEN INTO NEW BRUNSWICK FRIDAY MORNING. THE PRIMARY LOW WILL MOVE FROM GREAT LAKES NORTHEASTWARD ACROSS FAR NORTHERN MAINE FRIDAY. EXPECT HEAVIES SNOW FROM PRIMARY LOW TO STAY NORTHWEST OF THE FORECAST AREA FRIDAY WHILE RESULTING IN MIXED PRECIPITATION OVER THE REMAINDER OF THE REGION. GFS...NAM12 AND ECMWF INDICATE HIGHEST AMOUNTS SOUTH. WITH COLD AIR DAMMING INLAND...SEA SURFACE TEMPERATURE IN MID 40S AND SOME INSTABILITY ALOFT EXPECT COASTAL FRONT TO BE FACTOR IN ENHANCING QPF AMOUNT SOUTH. FOR POPS HAVE BLENDED THE NAM12...GFS40 AND SREF THEN MANUALLY ADJUSTED. TEMPERATURE GRIDS RUN ON NAM12 INTO FRIDAY EVENING THEN TRANSITION TO GMOS. PRECIPITATION TYPE GENERATED WITH THICKNESS TOOL RUN ON 50/50 BLEND OF THE NAM AND GFS. SNOW AMOUNT GENERATED WITH OFFICE SNOW FROM THICKNESS RUN ON NAM12. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE EXTENDED MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA THROUGH EARLY TUESDAY AFTERNOON. A LOW PRESSURE SYSTEM THAT STARTS IN THE SOUTHERN PLAINS ON MONDAY WILL TRACK NORTHEAST INTO THE GREAT LAKES REGION BY EARLY TUESDAY MORNING. THIS LOW WILL MOVE INTO SOUTHERN QUEBEC BY TUESDAY AFTERNOON WITH ITS COLD FRONT EXTENDED SOUTH ALONG THE BOARDER WITH MAINE. BY EARLY WEDNESDAY MORNING THE COLD FRONT WILL PUSH THROUGH THE AREA AND HIGHER PRESSURE WILL BUILD INTO THE REGION THROUGH THE END OF THE PERIOD. LOADED GMOS. ADJUSTED SKY AND POP GRIDS TO BETTER SUPPORT ONE ANOTHER. LOADED NAWAVE 4 FOR SEAS. PLUS 15 PERCENT FOR WINDS GUST OVER LAND 20 PERCENT OVER WATER. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE REGION OVERNIGHT. CONDITIONS WILL LOWER TO MVFR/IFR LEVELS...FROM SOUTH TO NORTH ACROSS THE REGION...THURSDAY WITH PRECIPITATION EXPANDING NORTH. SHORT TERM: EXPECT IFR/MVFR CONDITIONS THROUGH FRIDAY NIGHT THEN VFR CONDITIONS SATURDAY THROUGH MONDAY. && .MARINE... NEAR TERM: CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS OVERNIGHT. WINDS WILL THEN RAPIDLY INCREASE TO GALE LEVELS THURSDAY...WITH A GALE WARNING IN EFFECT STARTING THURSDAY AFTERNOON. VISIBILITIES WILL LOWER IN DEVELOPING SNOW AND RAIN THURSDAY. SHORT TERM: HAVE USED THE NAM12 FOR WIND GRIDS. FOR WAVES HAVE USED THE SWAN/NAM UNTIL 0000Z SATURDAY THEN TRANSITION TO THE WNA/4. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 PM EST FRIDAY FOR MEZ001-002. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 PM EST FRIDAY FOR MEZ003>006-011. WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR MEZ016-017-029-030. WINTER WEATHER ADVISORY FROM NOON TODAY TO 7 PM EST FRIDAY FOR MEZ010-015-031. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST FRIDAY FOR MEZ032. MARINE...GALE WARNING FROM NOON TODAY TO 10 PM EST THIS EVENING FOR ANZ050>052. && $$ NEAR TERM...FOISY/MCW SHORT TERM...MIGNONE LONG TERM...NORTON AVIATION...FOISY/MCW MARINE...FOISY/MCW/MIGNONE
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1106 PM EST WED JAN 11 2012 .SYNOPSIS... LOW PRESSURE WILL BRING RAIN SHOWERS INTO THURSDAY. HIGHER MOUNTAINS MAY UNDERGO A PERIOD OF FREEZING RAIN AND DENSE FOG OVERNIGHT. A STRONG COLD FRONT WILL CAUSE A FAST TEMPERATURE DROP AND CHANGE TO SNOW SHOWERS AND SLIPPERY CONDITIONS LATE THURSDAY NIGHT, AND BE ACCOMPANIED BY GUSTY WIND THAT WILL CONTINUE INTO FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... PER RECENT SURFACE AND RADAR DATA, COUPLED WITH RECENT HRRR AND WRF-NMM MODEL OUTPUT, EXPECT PATCHES OF FREEZING RAIN AND DENSE FOG OVERNIGHT. HAVE ISSUED A FREEZING RAIN ADVISORY TIL 6 AM FOR TUCKER COUNTY WV AND GARRETT COUNTY MD. AS LOW PRESSURE CENTER GETS CLOSER, SHOWERS HAVE DECREASED IN COVERAGE WEST OF THE MOUNTAINS. WIND HAVE BEGUN GUSTING OVER 30 MPH DOWNWIND OF THE SOUTHERN MOUNTAINS, WHICH WILL HAVE TO BE MONITORED. RECENT MODEL OUTPUT SUGGEST THERE CAN BE A SECOND SURGE OF SHOWERS LATE TONIGHT INTO FRIDAY MORNING, MAINLY NEAR THE MOUNTAINS. TEMPERATURES WILL BE NEARLY STEADY IN SOUTHERLY FLOW ON FRONT SIDE OF SYSTEM. LOW PRESSURE EXITS DURING THE DAY THURSDAY WITH SHOWERS DIMINISHING DURING THE MORNING. TEMPERATURES WILL STAY ABOVE NORMAL THURSDAY AHEAD OF APPROACHING COLD FRONT. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... BLEND OF RECENT SREF MODEL OUTPUT SHOWS STRONG COLD FRONT WILL MOVE EASTWARD THROUGH THE UPPER OHIO VALLEY THURSDAY NIGHT. THIS WILL CAUSE A FAST TEMPERATURE DROP AND SUBSEQUENT FAST CHANGE OF RAIN SHOWERS TO SNOW SHOWERS TOWARD MIDNIGHT. THE FAST CHANGE CAN RESULT IN ICY CONDITIONS QUICKLY DEVELOPING WHICH HAS BEEN MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK. WITH COLD FLOW BEING MAINLY FROM THE WEST AND SOUTHWEST, EXPECT SNOW ACCUMULATION AMOUNT TO BE IN SUBADVISORY RANGE LATE THURSDAY NIGHT INTO DAYTIME FRIDAY. HOWEVER, IMPACT OF ICING CONDITIONS MAY ALSO BE A PLAYER IN HEADLINE DECISIONS. NAM MODEL PROFILES SHOW POST FRONTAL WIND GUSTS CAN REACH THE 30 TO 40 MPH RANGE LATE THURSDAY NIGHT AND FRIDAY. AS SYSTEM MOVES TO NEW ENGLAND SATURDAY, SCATTERED SNOW SHOWERS WILL CONTINUE WITH WINDS ONLY SLOWLY DIMINISHING. FORECASTED TEMPERATURES CLOSE TO BLEND OF GFS AND NAM MOS WHICH LOOK TO HAVE A GOOD HANDLE ON COLD AIR. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... ANOTHER SHORTWAVE TROUGH AND ASSOCIATED SURFACE WEAK LOW IS PROGGED TO CROSS THE OHIO VALLEY SATURDAY NIGHT AND EARLY SUNDAY BRINGING SCATTERED SNOW SHOWERS. RIDGING AT THE SURFACE AND ALOFT SHOULD PROVIDE DRY WEATHER LATER SUNDAY INTO MONDAY. THE NEXT UPPER TROUGH WILL SWING A COLD FRONT ACROSS THE GREAT LAKES REGION TUESDAY...ALONG WITH SCATTERED RAIN AND SNOW SHOWERS. PRECIPITATION IS FORECAST TO TAPER OFF WEDNESDAY WITH JUST A FEW LINGERING SHOWERS NORTH AND ALONG THE RIDGES. NEAR NORMAL TEMPERATURES SHOULD MODERATE TO BETWEEN 5 AND 10 DEGREES ABOVE NORMAL BY TUESDAY...AND RETURN TO NEAR NORMAL BY MIDWEEK. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... WIDESPREAD RAIN ACROSS WESTERN PENNSYLVANIA TAPERS OFF ACROSS EASTERN OHIO AND NORTHERN WEST VIRGINIA. CONDITIONS RANGE FROM IFR AT FKL AND DUJ TO VFR SOUTH OF PITTSBURGH. AS RAIN SHIELD CONTINUES TO MOVE TO THE NORTH...EXPECT THAT ALL SITES WILL RISE TO VFR FOR AT LEAST A FEW HOURS. WITH SO MUCH MOISTURE AROUND...EXPECT THAT CEILINGS WILL DROP BACK TO IFR AT ALL TERMINALS. WINDS AROUND 10 KT SHOULD DECREASE SLIGHTLY OVERNIGHT. HOWEVER...LOW LEVEL WIND SHEAR IS EXPECTED TO DEVELOP FOR A FEW HOURS AT ALL SITES EXCEPT ZZV. LLWS WILL NOT PERSIST FOR TOO LONG...DIMINISHING BY MIDNIGHT. WHILE A CHANCE OF SHOWERS REMAINS IN THE FORECAST ON THURSDAY...COVERAGE IS NOT HIGH ENOUGH TO WARRANT MENTION IN TAFS AT THIS TIME. IFR CONDITIONS MAY RISE TO MVFR BY THE AFTERNOON. GUSTY WINDS WILL DEVELOP...WITH 20 KTS EXPECTED ON THURSDAY AFTERNOON AND DIMINISHING AT SUNSET. OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... COLDER AIR WILL PUSH INTO THE REGION THURSDAY NIGHT AND CHANGE PRECIPITATION OVER TO SNOW SHOWERS. SURFACE WIND GUSTS OVER 30KT ARE POSSIBLE THURSDAY NIGHT AND FRIDAY. MVFR AND AREAS OF IFR RESTRICTIONS WILL CONTINUE THROUGH SATURDAY MORNING. SCATTERED SNOW SHOWERS SHOULD TAPER OFF DURING THE DAY SATURDAY. ANOTHER LOW PRESSURE SYSTEM WILL SWING ACROSS THE OH VALLEY SUNDAY...BRINGING THE POTENTIAL FOR RESTRICTIONS. A SURFACE RIDGE IS PROGGED TO BUILD IN SUNDAY NIGHT AND MONDAY...WITH CONDITIONS EXPECTED TO IMPROVE TO VFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZING RAIN ADVISORY UNTIL 6 AM EST THURSDAY FOR MDZ001. OH...NONE. PA...NONE. WV...FREEZING RAIN ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ041. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 PM EST THU JAN 12 2012 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .UPDATE... LATEST RADAR IMAGERY IS SHOWING AN INCREASE IN AREAL COVERAGE OF SNOWFALL ACROSS THE SOUTH CENTRAL PORTIONS OF THE CWA. GIVEN RADAR TRENDS IN ADDITION TO SUPPORT FROM THE HRRR AND 12Z RUN OF THE LOCAL WRF PLACING HIGHER QPF FARTHER EAST...HAVE OPTED TO PUT MENOMINEE COUNTY IN A WINTER WEATHER ADVISORY. OBSERVATIONS ARE ALSO INDICATING THAT SNOW TO LIQUID RATIOS ARE TRENDING SLIGHTLY HIGHER IN THIS REGION. RESULTING SNOW TOTALS SHOULD BE 2 TO 5 INCHES...WITH THE HIGHEST AMOUNTS ACROSS THE SOUTHERN HALF OF THE COUNTY. THE HEAVIEST SNOW SHOULD FALL DURING THE AFTERNOON AND EVENING. ELSEWHERE...COVERAGE OF THE SNOW REMAINS ON TRACK. A SLIGHT INCREASE IN POPS WERE MADE FROM MUNISING TO ESCANABA FOR THIS AFTERNOON TO ACCOUNT FOR THE CURRENT TRENDS AND SHARP EDGE OF THE PRECIPITATION SHIELD. FATHER WEST...LAKE ENHANCEMENT ACROSS PORTIONS OF MARQUETTE AND BARAGA COUNTY ARE HAS BECOME WELL ESTABLISHED OVER THE PAST HOUR. AS FOR TEMPERATURES...HIGHS HAVE LIKELY ALREADY OCCURRED ACROSS MUCH OF THE CWA AS CONTINUOUS CAA AND THICK CLOUD COVER RESULT IN STEADY OR SLIGHTLY DECREASING TEMPERATURES THROUGHOUT THE AFTERNOON. PATCHY FOG ACROSS INTERIOR LOCATIONS OF THE EASTERN CWA SHOULD DISSIPATE QUICKLY BY EARLY AFTERNOON. WINDS HAVE BECOME NORTHERLY AT KERY AND VIS HAS INCREASED SLIGHTLY OVER THE LAST HOUR. && .DISCUSSION... WATER VAPOR LOOP SHOWS MID-UPR TROUGH DIGGING THROUGH THE CENTRAL PLAINS. 3H JET MAX ROUNDING THE BASE OF THIS TROUGH AND ASSOC DIVERGENCE IN LEFT EXIT REGION OF THIS JET WILL AID IN RAPID DEEPENING OF SFC LOW/STORM SYSTEM OVER NRN OHIO ATTM. THIS STORM SYSTEM AND FAIRLY DEEP MOISTURE WRAPPING AROUND IT WILL HELP BRING SIGNIFICANT LAKE ENHANCED TO PORTIONS OF WEST AND NCNTRL UPPER MI THROUGH FRIDAY. TODAY...PERSISTENT 800-700 MB FGEN HAS HELPED SUSTAIN OCCASIONALLY MODERATE SNOW FM MQT INTO DICKINSON COUNTY AS NOTED ON LATEST RADAR LOOP. MODELS SHOW FGEN PERSISTING INTO THE EARLY AFTERNOON HRS OVER GENERALLY THIS SAME AREA SO WOULD NOT BE SURPRISED TO SEE MODERATE SNOW CONTINUE AT TIMES. WHILE WRN COUNTIES WILL BE FARTHER AWAY FROM SYNOPTIC FORCING FROM STORM SYSTEM OVER THE CENTRAL GREAT LAKES...CONVERGENT NRLY FLOW AND GREATER INSTABILITY FROM COLDER 850 MB TEMPS OF -12 TO -14C...ALONG WITH FAVORABLE DENDRITIC SNOW GROWTH AND TERRAIN ENHANCED LIFT WILL AID MODERATE TO HEAVY SNOW ACCUMULATIONS. EXPECT 2 TO 5 INCHES OVER THESE AREAS WHERE WINTER STORMS WARNINGS ARE ALREADY IN PLACE. ALSO LOOK FOR HIGHER TERRAIN OF BARAGA AND WRN MQT TO SEE 3 TO 5 INCHES OF ACCUMULATION WHERE WEAK TO MODERATE SYNOPTIC FORCING AND UPSLOPE ENHANCED LIFT SHOULD OVERCOME MARGINAL INSTABILITY...SO WARNING STILL LOOKS GOOD FOR THESE COUNTIES AS WELL. KEPT ADVISORY GOING FOR SRN HOUGHTON...IRON AND DICKINSON COUNTIES THROUGH TONIGHT ALTHOUGH I AM A BIT CONCERNED THAT SNOW COULD TAPER OFF QUICKLY TONIGHT FOR DICKINSON AND IRON AND SOME AREAS COULD HAVE A HARD TIME REACHING ADVISORY CRITERIA (2-4 INCHES/12 HR). ISSUED A WINTER WX ADVISORY FOR ALGER COUNTY THIS AFTERNOON THROUGH FRIDAY AS NORTHERLY FLOW AND INCREASING INSTABILITY FROM COLDER TEMPS MOVING IN FROM THE WEST LATER THIS AFTERNOON AND TONIGHT SHOULD GET LAKE ENHANCED SNOW PRETTY GOOD ESPECIALLY OVER THE WRN HALF OF THE COUNTY. LOOK FOR TOTAL ACCUMS OF 6 TO 10 INCHES THIS AFTERNOON THROUGH FRIDAY OVER ALGER. CANCELLED WATCH FOR NRN SCHOOLCRAFT AND OPTED NOT TO ISSUE ANY HEADLINES FOR NRN SCHOOLCRAFT OR LUCE COUNTY AS CYCLONIC NNE FLOW WILL NOT BE A FAVORABLE FETCH ACROSS LAKE SUPERIOR TO RECEIVE SIGNIFICANT LES ACCUMS THROUGH FRIDAY. TONIGHT...WITH SFC LOW/850MB LOWS WELL SE OF THE AREA OVER LAKE HURON...POTENTIAL FOR SIGNIFICANT SYNOPTIC SNOW LOOKS LIMITED AND MODELS GENERALLY SHOW A DIMINISHING TREND TO SNOW OVER AREAS AWAY FROM LAKE SUPERIOR BY THIS EVENING. EXPECT NO MORE THAN AN INCH OR TWO OF SYNOPTIC SNOW TONIGHT. CLOSE TO LAKE SUPERIOR...IT WILL BE A FAVORABLE SETUP FOR LAKE ENHANCEMENT IN THE N WIND FAVORED AREAS. AS COLDER AIR SPREADS IN FROM THE WEST TONIGHT THE DENDRITIC SNOW GROWTH ZONE (DGZ) WILL FALL FIRMLY INTO THE CONVECTIVE BOUNDARY LAYER (FM 1-3 KFT OFF FCST SNDGS) WHILE TERRAIN ENHANCED UPWARD MOTION LAYER WILL ALSO AID LIFT IN THIS LYR. INCREASING SNOW-TO-WATER RATIOS SHOULD RESULT IN MDT/POSSIBLY HVY SNOW ACCUMULATIONS W AND NCNTRL. COMBINED WITH GUSTY WINDS...BLOWING AND DRIFTING SNOW WILL ALSO ADD TO HAZARDOUS CONDITIONS ON AREA ROADS. WOULD NOT BE SURPRISED TO SEE 6-8 INCH AMOUNTS TONIGHT WHERE TERRAIN ENHANCEMENT IS MAXIMIZED (AROUND KIWD AND HURON MTNS). FRIDAY...MUCH DRIER AIR WILL MAKE SHARP INROADS FROM W TO E FRI WITH INVERSION HGTS FALLING AT OR BLO 3KFT. AS A RESULT...SNOW INTENSITY WILL DIMINISH SIGNIFICANTLY FROM W TO E THRU THE DAY (W IN THE MORNING...E IN THE AFTN). ALTHOUGH CONVECTIVE LAYER WILL BECOME SHALLOW...DGZ WILL STILL BE CENTERED WITHIN THE CBL...ALLOWING FOR LIGHTER FLUFFY ACCUMULATIONS TO CONTINUE. FRI NIGHT INTO SATUURDAY...HIGH PRES RIDGE SLIPPING INTO THE W FRI NIGHT MAY ALLOW FOR A VERY COLD NIGHT IF SKIES CLEAR. LOWERED TEMPS WELL INTO THE SINGLE DIGITS BLO ZERO OVER THE WRN INTERIOR WHERE THERE SHOULD BE PARTIAL CLEARING...BUT IT COULD REACH -10F OR COLDER IF SKIES CLEAR COMPLETELY FOR A FEW HRS GIVEN FRESH SNOW COVER. SOME LIGHT LES SHOULD CONTINUE INTO FRI NIGHT INTO SAT FOR PORTIONS OF THE KEWEENAW AND NCNTRL WITH LIGHT CONVERGENT ONSHORE WINDS EXPECTED. SUN THRU WED...ARCTIC AIR WILL BEGIN POOLING OVER CANADA DURING THIS PERIOD AS RIDGE AMPLIFIES N THRU WRN ALASKA/BERING SEA INTO THE ARCTIC. 00Z MODELS NOW ADVERTISE A SERIES OF CLIPPER SHORTWAVES ROTATING THROUGH THE UPPER GREAT LAKES NEXT WEEK ROTATING AROUND BROAD POLAR VORTEX ENCOMPASSING MUCH OF NRN CANADA. FIRST SHORTWAVE MOVING THROUGH ON TUE COULD USHER IN 850 MB TEMPS COLDER THAN -20F TUE NIGHT AS NOTED ON THE 00Z ECMWF AND THE SECOND SHORTWAVE MOVING THROUGH WED NIGHT COULD BRING IN 850 MB TEMPS BTWN -25 AND -30F...THE COLDEST AIR OF THE SEASON THUS FAR. WILL NEED TO KEEP A CLOSE EYE ON MODEL TRENDS FOR NEXT WEEK AS MORE LAKE EFFECT SNOW COULD BE IN STORE FOR NW SNOW BELTS BEGINNING TUE AND CONTINUING INTO THU....AND WIND CHILL HEADLINES COULD BE A REAL POSSIBILITY FOR SOME AREAS MID TO LATE WEEK. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... STEADY SNOW HAS SPREAD ACROSS CENTRAL UPPER MICHIGAN WHILE A SLIGHT DECREASE IN SNOW COVERAGE HAS APPEARED ACROSS THE WEST WHERE TRANSISITION TO LAKE EFFECT SNOW IS UNDERWAY. ALL LOCATIONS SHOULD REMAIN PREDOMINATELY AT IFR CONDITIONS INTO THIS EVENING. KCMX MAY FALL TO VLIFR AS HEAVIER LAKE EFFECT SNOW SHOWERS DECREASE VIS. BY THIS EVENING...DRIER AIR AND A SLIGHT VEERING OF THE WINDS AT KCMX SHOULD LIMIT HEAVIER SNOW. KIWD SHOULD ALSO SEE CONSISTENT LAKE EFFECT SNOW THROUGH THE NIGHT BEFORE DRIER AIR MOVES IN. STEADY SNOW AT KSAW WILL GIVE WAY TO HEAVIER SNOW DURING THE OVERNIGHT HOURS AS LAKE ENHANCEMENT INCREASES. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/.. LOW PRESSURE DEEPENING OVER THE CENTRAL GREAT LAKES THROUGH TONIGHT RESULTS IN WINDS OUT OF THE NORTH INCREASING TO GALES LATER TODAY THROUGH MUCH OF FRIDAY. OTHER HAZARD OF NOTE IS HEAVY FREEZING SPRAY THAT WILL DEVELOP OVER MOST OF THE LAKE LATE TODAY THROUGH FRIDAY MORNING. ALL HAZARDS WILL SUBSIDE BY FRIDAY EVENING. WINDS THEN WILL DECREASE TO LESS THAN 25 KTS THROUGH MOST OF THE WEEKEND. SOUTH WINDS PICK UP AGAIN SUNDAY NIGHT AHEAD OF LOW PRESSURE TROUGH MOVING ACROSS. STRONGEST WINDS WILL BE OVER THE EASTERN HALF OF THE LAKE. WINDS BECOME NORTHWESTERLY LATER MONDAY INTO TUESDAY WITH GALE FORCE WINDS POSSIBLE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ FRIDAY FOR MIZ010-084. WINTER STORM WARNING UNTIL 1 PM EST /NOON CST/ FRIDAY FOR MIZ001>003-009. WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MIZ006. WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ004-005. WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ011-012. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 1 PM EST FRIDAY FOR LSZ267. HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 PM EST FRIDAY FOR LSZ266. GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ244-245-263>266. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1 PM EST /NOON CST/ FRIDAY FOR LSZ162-240>244- 263-264. GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ248>250. LAKE MICHIGAN... NONE. && $$ UPDATE...TK DISCUSSION...VOSS AVIATION...TK MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1140 AM EST THU JAN 12 2012 .UPDATE... LATEST RADAR IMAGERY IS SHOWING AN INCREASE IN AREAL COVERAGE OF SNOWFALL ACROSS THE SOUTH CENTRAL PORTIONS OF THE CWA. GIVEN RADAR TRENDS IN ADDITION TO SUPPORT FROM THE HRRR AND 12Z RUN OF THE LOCAL WRF PLACING HIGHER QPF FARTHER EAST...HAVE OPTED TO PUT MENOMINEE COUNTY IN A WINTER WEATHER ADVISORY. OBSERVATIONS ARE ALSO INDICATING THAT SNOW TO LIQUID RATIOS ARE TRENDING SLIGHTLY HIGHER IN THIS REGION. RESULTING SNOW TOTALS SHOULD BE 2 TO 5 INCHES...WITH THE HIGHEST AMOUNTS ACROSS THE SOUTHERN HALF OF THE COUNTY. THE HEAVIEST SNOW SHOULD FALL DURING THE AFTERNOON AND EVENING. ELSEWHERE...COVERAGE OF THE SNOW REMAINS ON TRACK. A SLIGHT INCREASE IN POPS WERE MADE FROM MUNISING TO ESCANABA FOR THIS AFTERNOON TO ACCOUNT FOR THE CURRENT TRENDS AND SHARP EDGE OF THE PRECIPITATION SHIELD. FATHER WEST...LAKE ENHANCEMENT ACROSS PORTIONS OF MARQUETTE AND BARAGA COUNTY ARE HAS BECOME WELL ESTABLISHED OVER THE PAST HOUR. AS FOR TEMPERATURES...HIGHS HAVE LIKELY ALREADY OCCURRED ACROSS MUCH OF THE CWA AS CONTINUOUS CAA AND THICK CLOUD COVER RESULT IN STEADY OR SLIGHTLY DECREASING TEMPERATURES THROUGHOUT THE AFTERNOON. PATCHY FOG ACROSS INTERIOR LOCATIONS OF THE EASTERN CWA SHOULD DISSIPATE QUICKLY BY EARLY AFTERNOON. WINDS HAVE BECOME NORTHERLY AT ERY AND VIS HAS INCREASED SLIGHTLY OVER THE LAST HOUR. && PREV DISCUSSION...ISSUED AT 649 AM EST THU JAN 12 2012... .DISCUSSION... WATER VAPOR LOOP SHOWS MID-UPR TROUGH DIGGING THROUGH THE CENTRAL PLAINS. 3H JET MAX ROUNDING THE BASE OF THIS TROUGH AND ASSOC DIVERGENCE IN LEFT EXIT REGION OF THIS JET WILL AID IN RAPID DEEPENING OF SFC LOW/STORM SYSTEM OVER NRN OHIO ATTM. THIS STORM SYSTEM AND FAIRLY DEEP MOISTURE WRAPPING AROUND IT WILL HELP BRING SIGNIFICANT LAKE ENHANCED TO PORTIONS OF WEST AND NCNTRL UPPER MI THROUGH FRIDAY. TODAY...PERSISTENT 800-700 MB FGEN HAS HELPED SUSTAIN OCCASIONALLY MODERATE SNOW FM MQT INTO DICKINSON COUNTY AS NOTED ON LATEST RADAR LOOP. MODELS SHOW FGEN PERSISTING INTO THE EARLY AFTERNOON HRS OVER GENERALLY THIS SAME AREA SO WOULD NOT BE SURPRISED TO SEE MODERATE SNOW CONTINUE AT TIMES. WHILE WRN COUNTIES WILL BE FARTHER AWAY FROM SYNOPTIC FORCING FROM STORM SYSTEM OVER THE CENTRAL GREAT LAKES...CONVERGENT NRLY FLOW AND GREATER INSTABILITY FROM COLDER 850 MB TEMPS OF -12 TO -14C...ALONG WITH FAVORABLE DENDRITIC SNOW GROWTH AND TERRAIN ENHANCED LIFT WILL AID MODERATE TO HEAVY SNOW ACCUMULATIONS. EXPECT 2 TO 5 INCHES OVER THESE AREAS WHERE WINTER STORMS WARNINGS ARE ALREADY IN PLACE. ALSO LOOK FOR HIGHER TERRAIN OF BARAGA AND WRN MQT TO SEE 3 TO 5 INCHES OF ACCUMULATION WHERE WEAK TO MODERATE SYNOPTIC FORCING AND UPSLOPE ENHANCED LIFT SHOULD OVERCOME MARGINAL INSTABILITY...SO WARNING STILL LOOKS GOOD FOR THESE COUNTIES AS WELL. KEPT ADVISORY GOING FOR SRN HOUGHTON...IRON AND DICKINSON COUNTIES THROUGH TONIGHT ALTHOUGH I AM A BIT CONCERNED THAT SNOW COULD TAPER OFF QUICKLY TONIGHT FOR DICKINSON AND IRON AND SOME AREAS COULD HAVE A HARD TIME REACHING ADVISORY CRITERIA (2-4 INCHES/12 HR). ISSUED A WINTER WX ADVISORY FOR ALGER COUNTY THIS AFTERNOON THROUGH FRIDAY AS NORTHERLY FLOW AND INCREASING INSTABILITY FROM COLDER TEMPS MOVING IN FROM THE WEST LATER THIS AFTERNOON AND TONIGHT SHOULD GET LAKE ENHANCED SNOW PRETTY GOOD ESPECIALLY OVER THE WRN HALF OF THE COUNTY. LOOK FOR TOTAL ACCUMS OF 6 TO 10 INCHES THIS AFTERNOON THROUGH FRIDAY OVER ALGER. CANCELLED WATCH FOR NRN SCHOOLCRAFT AND OPTED NOT TO ISSUE ANY HEADLINES FOR NRN SCHOOLCRAFT OR LUCE COUNTY AS CYCLONIC NNE FLOW WILL NOT BE A FAVORABLE FETCH ACROSS LAKE SUPERIOR TO RECEIVE SIGNIFICANT LES ACCUMS THROUGH FRIDAY. TONIGHT...WITH SFC LOW/850MB LOWS WELL SE OF THE AREA OVER LAKE HURON...POTENTIAL FOR SIGNIFICANT SYNOPTIC SNOW LOOKS LIMITED AND MODELS GENERALLY SHOW A DIMINISHING TREND TO SNOW OVER AREAS AWAY FROM LAKE SUPERIOR BY THIS EVENING. EXPECT NO MORE THAN AN INCH OR TWO OF SYNOPTIC SNOW TONIGHT. CLOSE TO LAKE SUPERIOR...IT WILL BE A FAVORABLE SETUP FOR LAKE ENHANCEMENT IN THE N WIND FAVORED AREAS. AS COLDER AIR SPREADS IN FROM THE WEST TONIGHT THE DENDRITIC SNOW GROWTH ZONE (DGZ) WILL FALL FIRMLY INTO THE CONVECTIVE BOUNDARY LAYER (FM 1-3 KFT OFF FCST SNDGS) WHILE TERRAIN ENHANCED UPWARD MOTION LAYER WILL ALSO AID LIFT IN THIS LYR. INCREASING SNOW-TO-WATER RATIOS SHOULD RESULT IN MDT/POSSIBLY HVY SNOW ACCUMULATIONS W AND NCNTRL. COMBINED WITH GUSTY WINDS...BLOWING AND DRIFTING SNOW WILL ALSO ADD TO HAZARDOUS CONDITIONS ON AREA ROADS. WOULD NOT BE SURPRISED TO SEE 6-8 INCH AMOUNTS TONIGHT WHERE TERRAIN ENHANCEMENT IS MAXIMIZED (AROUND KIWD AND HURON MTNS). FRIDAY...MUCH DRIER AIR WILL MAKE SHARP INROADS FROM W TO E FRI WITH INVERSION HGTS FALLING AT OR BLO 3KFT. AS A RESULT...SNOW INTENSITY WILL DIMINISH SIGNIFICANTLY FROM W TO E THRU THE DAY (W IN THE MORNING...E IN THE AFTN). ALTHOUGH CONVECTIVE LAYER WILL BECOME SHALLOW...DGZ WILL STILL BE CENTERED WITHIN THE CBL...ALLOWING FOR LIGHTER FLUFFY ACCUMULATIONS TO CONTINUE. FRI NIGHT INTO SATUURDAY...HIGH PRES RIDGE SLIPPING INTO THE W FRI NIGHT MAY ALLOW FOR A VERY COLD NIGHT IF SKIES CLEAR. LOWERED TEMPS WELL INTO THE SINGLE DIGITS BLO ZERO OVER THE WRN INTERIOR WHERE THERE SHOULD BE PARTIAL CLEARING...BUT IT COULD REACH -10F OR COLDER IF SKIES CLEAR COMPLETELY FOR A FEW HRS GIVEN FRESH SNOW COVER. SOME LIGHT LES SHOULD CONTINUE INTO FRI NIGHT INTO SAT FOR PORTIONS OF THE KEWEENAW AND NCNTRL WITH LIGHT CONVERGENT ONSHORE WINDS EXPECTED. SUN THRU WED...ARCTIC AIR WILL BEGIN POOLING OVER CANADA DURING THIS PERIOD AS RIDGE AMPLIFIES N THRU WRN ALASKA/BERING SEA INTO THE ARCTIC. 00Z MODELS NOW ADVERTISE A SERIES OF CLIPPER SHORTWAVES ROTATING THROUGH THE UPPER GREAT LAKES NEXT WEEK ROTATING AROUND BROAD POLAR VORTEX ENCOMPASSING MUCH OF NRN CANADA. FIRST SHORTWAVE MOVING THROUGH ON TUE COULD USHER IN 850 MB TEMPS COLDER THAN -20F TUE NIGHT AS NOTED ON THE 00Z ECMWF AND THE SECOND SHORTWAVE MOVING THROUGH WED NIGHT COULD BRING IN 850 MB TEMPS BTWN -25 AND -30F...THE COLDEST AIR OF THE SEASON THUS FAR. WILL NEED TO KEEP A CLOSE EYE ON MODEL TRENDS FOR NEXT WEEK AS MORE LAKE EFFECT SNOW COULD BE IN STORE FOR NW SNOW BELTS BEGINNING TUE AND CONTINUING INTO THU....AND WIND CHILL HEADLINES COULD BE A REAL POSSIBILITY FOR SOME AREAS MID TO LATE WEEK. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... STEADY AND WIDESPREAD SNOW WL TRANSITION TO LAKE EFFECT SNOW SHOWERS BY TONIGHT. IFR CONDITIONS WILL BE PROMINENT THROUGH THE PERIOD. AREAS FAVORED BY NORTHERLY WINDS...KIWD AND KSAW...WILL HAVE BEST CHANCE TO SEE PROLONGED CONDITIONS BLO ALTERNATE LANDING MINS. DUE TO STRONG GUSTY NORTHERLY WINDS AND HEAVIER SNOW/BLOWING SNOW THERE IS A RISK THAT CONDITIONS AT KSAW MAY NEAR AIRFIELD MINIMUMS LATE TODAY THROUGH MUCH OF TONIGHT. CONDITIONS WILL BEGIN TO IMPROVE AT ALL SITES BY FRIDAY AFTERNOON. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/.. LOW PRESSURE DEEPENING OVER THE CENTRAL GREAT LAKES THROUGH TONIGHT RESULTS IN WINDS OUT OF THE NORTH INCREASING TO GALES LATER TODAY THROUGH MUCH OF FRIDAY. OTHER HAZARD OF NOTE IS HEAVY FREEZING SPRAY THAT WILL DEVELOP OVER MOST OF THE LAKE LATE TODAY THROUGH FRIDAY MORNING. ALL HAZARDS WILL SUBSIDE BY FRIDAY EVENING. WINDS THEN WILL DECREASE TO LESS THAN 25 KTS THROUGH MOST OF THE WEEKEND. SOUTH WINDS PICK UP AGAIN SUNDAY NIGHT AHEAD OF LOW PRESSURE TROUGH MOVING ACROSS. STRONGEST WINDS WILL BE OVER THE EASTERN HALF OF THE LAKE. WINDS BECOME NORTHWESTERLY LATER MONDAY INTO TUESDAY WITH GALE FORCE WINDS POSSIBLE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ FRIDAY FOR MIZ010-084. WINTER STORM WARNING UNTIL 1 PM EST /NOON CST/ FRIDAY FOR MIZ001>003-009. WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MIZ006. WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ004-005. WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ011-012. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 1 PM EST FRIDAY FOR LSZ267. HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 PM EST FRIDAY FOR LSZ266. GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ244-245-263>266. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1 PM EST /NOON CST/ FRIDAY FOR LSZ162-240>244- 263-264. GALE WARNING FROM 3 PM THIS AFTERNOON TO 1 PM EST FRIDAY FOR LSZ248>250. LAKE MICHIGAN... NONE. && $$ UPDATE...TK DISCUSSION...VOSS AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
717 AM CST THU JAN 12 2012 .UPDATE... /717 AM CST THU JAN 12 2012/ MAIN BAND OF SNOW CONTINUES TO MOVE/PIVOT EAST INTO ILLINOIS...WITH SNOW SHOWERS AND FLURRIES LEFT IN ITS WAKE. MOST REPORTS HAVE ACCUMULATION ANYWHERE BETWEEN 0.5 AND 1.5 INCHES. THIS WAS ENOUGH SNOW TO CAUSE MAJOR TRAFFIC ISSUES ACROSS THE AREA...WITH NUMEROUS ACCIDENTS REPORTED. 500MB LOW HAS CLOSED OFF ACCORDING TO THE RUC AND IS ABOUT TO ROUND THE BASE OF THE TROF ACROSS SOUTHWEST MISSOURI. SHOULD SEE SNOW BECOME BETTER ORGANIZED AGAIN LATER THIS MORNING AND INTO THE AFTERNOON ACROSS NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS AS DEEP CYCLONIC FLOW DEVELOPS AS 500MB LOW MOVES ACROSS SOUTHERN ILLINOIS. THIS AREA OF SNOW MAY REACH AS FAR SOUTH AS ST. LOUIS METRO. OTHERWISE...SNOW SHOWERS AND FLURRIES WILL CONTINUE FOR MUCH OF THE DAY. WILL HAVE UPDATED FORECAST OUT IN A FEW MINUTES. CVKING && .DISCUSSION... /338 AM CST THU JAN 12 2012/ N-S BAND OF POST FRONTAL LIGHT SNOW WAS MOVING FAIRLY RAPIDLY EWD THROUGH OUR AREA EARLY THIS MRNG...CURRENTLY MOVING INTO THE ST LOUIS METRO AREA. THIS WAS ASSOCIATED WITH LOW-MID LEVEL FRONTOGENESIS BEHIND THE STRONG COLD FRONT WHICH MOVED THROUGH WED EVNG. THIS BAND OF SNOW SHOULD MOVE E OF OUR FORECAST AREA BY LATE MRNG. ADDITIONAL SNOW...MAINLY IN THE FORM OF LIGHT SNOW SHOWERS CAN BE EXPECTED LATE THIS MRNG AND AFTN AS AN UPPER LEVEL LOW CUTS OFF OVER NERN KS IN THE BASE OF THE UPPER LEVEL TROUGH EXTENDING FROM WRN MN S THROUGH ERN KS. THIS UPPER LEVEL LOW WILL DROP E-SEWD THROUGH SRN PORTIONS OF MO AND IL TODAY. THE BEST SNOW AMOUNTS WILL FALL LEFT OF THE TRACK OF THE UPPER LEVEL LOW. LIGHT SNOW SHOWERS OR FLURRIES WILL LINGER OVER MAINLY IL TGT WITH LITTLE ADDITIONAL ACCUMULATION EXPECTED TGT. TOTAL SNOW ACCUMULATION FROM WED NIGHT AND THU SHOULD RANGE FROM ONE INCH ACROSS PORTIONS OF SERN MO TO AROUND 2 INCHES IN THE ST LOUIS METRO AREA TO 3 INCHES OVER PARTS OF WEST CENTRAL IL. A WINTER WEATHER ADVISORY WILL CONTINUE TODAY OVER THE ENTIRE FORECAST AREA. STRONG AND GUSTY NWLY SFC WINDS CAN BE EXPECTED TODAY INTO THIS EVNG DUE TO A TIGHT SFC PRESSURE GRADIENT OVER OUR AREA BETWEEN A SFC LOW OVER THE GREAT LAKES REGION AND THE LARGE AND STRONG SFC RIDGE OVER THE PLAINS AND ROCKIES. BELOW NORMAL TEMPERATURES CAN BE EXPECTED TODAY WITH THE MODELS DROPPING THE -16 DEGREE C 850 MB ISOTHERM SEWD THROUGH MUCH OF OUR AREA TODAY BEHIND THE UPPER/SFC LOW. PLUS LOW LEVEL CLOUD COVER AND LIGHT SNOW WILL LEAD TO LITTLE DIURNAL RISE IN TEMPERATURES TODAY WITH HIGHS ONLY IN THE 20S. WILL GO BELOW MOS GUIDANCE FOR THE TEMPERATURE FORECAST DUE TO THE SNOW COVER EXPECTED. LOWS TGT AND FRI NGT SHOULD BE IN THE TEENS...POSSIBLY IN THE SINGLE DIGITS WHERE THERE IS BETTER SNOW COVER. THE SKY SHOULD SLOWLY CLEAR OUT LATE TGT AND FRI FROM THE SW TO NE. TEMPERATURES WILL BE WARMER ON SAT AS THE SFC WIND BACKS AROUND TO A SWLY DIRECTION AHEAD OF AN APPROACHING SFC TROUGH...AND AS LOW LEVEL WAA INCREASES AHEAD OF THIS TROUGH. THE MODELS ARE FORECASTING A NW FLOW SHORTWAVE TO DROP SEWD THROUGH ERN MO AND IL ON SAT WITH A BAND OF LIGHT PRECIPITATION LEFT OF THE TRACK OF THE VORT MAX ACROSS IL. IT SHOULD BE COLD ENOUGH FOR THIS PRECIPITATION TO FALL AS SNOW. THE NAM MODEL APPEARS OVERDONE WITH THE QPF BUT MAY BE ABLE TO PICK UP A DUSTING OF SNOW OVER THE NRN AND ERN PORTIONS OF THE FORECAST AREA FROM THIS FAST MOVING SYSTEM. TEMPERATURES SHOULD BE EVEN WARMER ON SUN AS THE UPPER LEVEL HEIGHTS RISE AND THE SFC WIND BECOMES SLY. THE NEXT CHANCE OF PRECIPITATION SHOULD BEGIN ON MON WITH TEMPERATURES WARM ENOUGH THAT IT SHOULD FALL AS LIQUID RAIN. THE PRECIPITATION MAY CHANGE TO SNOW BEFORE ENDING ON TUE AS COLDER AIR FILTERS SEWD INTO THE REGION BEHIND A COLD FRONT. GKS && .AVIATION... /507 AM CST THU JAN 12 2012/ BAND OF LIGHT TO MODERATE SNOW WILL CONTINUE TO PUSH EAST THIS MORNING...WITH REDEVELOPMENT OF SNOW SHOWERS EXPECTED IN ITS WAKE AS THE UPPER LOW CONTINUES TO DIG ACROSS MISSOURI AND ILLINOIS. NORTHWEST WINDS TO REMAIN STRONG AND GUSTY...WITH BLOWING SNOW AND REDUCED VISIBILITY. SNOW SHOWERS WILL TAPER TO FLURRIES THIS EVENING AND SKIES WILL SCT OVERNIGHT. TOTAL ACCUMULATION OF 1 TO 3 INCHES IS EXPECTED. SPECIFICS FOR KSTL... BAND OF MODERATE SNOW WILL BE PULLING EAST OF THE TERMINAL AROUND 12Z...WITH LIGHT SNOW CONTINUING THIS MORNING...AND SNOW SHOWERS INTO THE AFTERNOON. VISIBILITY WILL VARY...AND BE TIED TO BLOWING SNOW DUE TO STRONG AND GUSTY NORTHWEST WINDS. EXPECT A TOTAL SNOW ACCUMULATION OF 1 TO 2 INCHES. CONDITIONS TO IMPROVE THIS EVENING WITH VFR CONDITIONS RETURNING. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO- GASCONADE MO-IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MADISON MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO- OSAGE MO-PIKE MO-RALLS MO-REYNOLDS MO-SHELBY MO-ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WARREN MO-WASHINGTON MO. IL...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR ADAMS IL- BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL- JERSEY IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL- MONTGOMERY IL-PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
521 PM CST FRI JAN 13 2012 .AVIATION... 00Z TAFS FOR KOFK...KOMA AND KLNK. CLIPPER-TYPE SYSTEM SHOULD MOVE QUICKLY INTO NERN NEBRASKA AROUND 14/06Z AND THEN INTO SERN MO BY 14/18Z. THIS SYSTEM WILL BRING A SHIFT TO GUSTY NORTHWEST WINDS LATE TONIGHT/EARLY SATURDAY... AND POSSIBLY A PERIOD OF LOWER CLOUDS AND SCATTERED SNOW SHOWERS. SNOW CHCS APPEARED SOMEWHAT BETTER AT KOFK AND KOMA. SURFACE WINDS SHOULD RELAX SATURDAY AFTERNOON BEFORE TURNING TO S/SW IN THE EVENING AHEAD OF YET ANOTHER SYSTEM. CHERMOK && .PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/ SHORT TERM...TONIGHT THROUGH MONDAY. THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW MOVING IN FROM THE WEST MONDAY. AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY 20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY 12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING... SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST. ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA. MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END. ZAPOTOCNY LONG TERM...MONDAY NIGHT THROUGH FRIDAY. MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY HIGHS RANGED FROM 21 TO 49 AT OMAHA. LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING. THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY. THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS 6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST. ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE SOME LIGHT SNOW WITH THIS SCENARIO. DERGAN AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL SITES THROUGH THE TAF PERIOD. A FRONTAL BOUNDARY WILL APPROACH THE CWA THIS AFTERNOON...BRINGING WINDS AROUND TO THE SOUTHEAST AHEAD OF THE FRONT. OVERNIGHT...WINDS BEHIND THE FRONT ARE EXPECTED TO INCREASE AND SWITCH TO THE NORTHWEST. ROUKE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS BUFFALO NY
103 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX STORM SYSTEM APPROACHING FROM THE TENNESSEE VALLEY WILL SEND RAIN...AND A WINTRY MIX FOR THE EASTERN LAKE ONTARIO REGION...ACROSS THE EASTERN GREAT LAKES OVERNIGHT AND INTO THURSDAY MORNING. A BRIEF LULL IN THE PRECIPITATION ACROSS MUCH OF THE REGION LATER TOMORROW AS THE RAIN AND WINTERY MIX PUSHES NORTHWARD BEFORE ADDITIONAL RAIN CHANGING TO SNOW SWEEPS IN FROM THE WEST OVERNIGHT. WINDS WILL BECOME BLUSTERY FRIDAY WITH WIDESPREAD SNOWFALL...BECOMING MORE CONCENTRATED DOWNWIND OF BOTH OF THE LAKES...WITH THE POTENTIAL FOR THIS LAKE EFFECT SNOW TO CONTINUE INTO SATURDAY BEFORE DIMINISHING. && .NEAR TERM /THROUGH TODAY/... AS OF 06Z...RAIN HAS LIFTED ACROSS ALL OF WESTERN NEW YORK AND IS JUST NOW STARTING EAST OF LAKE ONTARIO AS A WINTRY MIX. WHILE TEMPERATURES ARE SAFELY ABOVE FREEZING ACROSS THE WESTERN COUNTIES... THE SAME CANNOT BE SAID FROM THE TUG HILL NORTH AND EAST. A WAVY FRONTAL BOUNDARY STRETCHED ACROSS THE NORTH COUNTRY AS OF 06Z WITH COLD AIR DAMMING EVIDENT ON A SFC ANALYSES FROM WATERTOWN ACROSS THE THOUSAND ISLANDS TO THE ST LAWRENCE VALLEY. TEMPERATURES NORTH OF THE BOUNDARY ARE IN THE TEENS AND 20S...AND WITH A NORTHEAST LOW LEVEL FLOW HOLDING IN PLACE THROUGH THE NIGHT AND LIKELY THROUGH A LARGE PART OF THURSDAY...A PROLONGED MIXED BAG OF FREEZING RAIN...SLEET AND EVEN A BIT OF WET SNOW WILL FALL. LIKE THE PREVIOUS SHIFT...AM CONCERNED ABOUT WHETHER ENOUGH ICE COULD ACCUMULATE TO WARRANT A WARNING VERSUS THE CURRENT WINTER WEATHER ADVISORY. QPF AMOUNTS WILL AVERAGE ABOUT A HALF INCH THROUGH MIDDAY THURSDAY...BUT ENOUGH OF THE PCPN SHOULD FALL AS SLEET TO KEEP FREEZING RAIN AMOUNTS BELOW WARNING CRITERIA. WILL HOLD ONTO THE ADVISORY FOR JEFFERSON AND LEWIS COUNTIES FOR NOW...ALTHOUGH IT MAY NEED TO BE EXTENDED DEEPER TO THURSDAY EVENING. AT THIS POINT... AM LEANING TOWARDS DROPPING THE ADVISORY WITH THE UPCOMING EARLY MONRING PACKAGE FOR OSWEGO COUNTY WHERE COLD AIR DAMMING IS NOT AN ISSUE. THE RAIN ACROSS THE REGION TYHROUGH DAYBREAK WILL BE THE RESULT OF BEING UNDER THE RR ENTRANCE REGION OF A 120 KT JET OVER QUEBEC AND CONVERGENCE FOUND ALONG A 50KT 900 HPA JET. DEEPEN MOISTURE IN THE LOWER LEVELS...WITH PWATS RISING TO NEAR +2SD OVERNIGHT WILL FUEL THE PRECIPITATION THROUGH THE OVERNIGHT. EXPECT BASIN QPF AVERAGES TO BE AROUND 0.40 TO 0.75 INCHES OVERNIGHT WITH THE HIGHEST TOTALS TOWARDS THE EAST...CLOSER TO THE CORE OF THE LLJ. ON THURSDAY...AN OCCLUDED FRONT FROM THE PRIMARY LOW OVER OHIO WILL PUSH NORTHWARD TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO BY AFTERNOON. DRIER AIR IN THE MID LEVELS (700MB AS PER THE GFS) WILL LIFT ACROSS THE REGION DURING THE DAY THURSDAY...SHUTTING DOWN THE STEADY RAIN AND MAKING THE PCPN MORE SPOTTY IN NATURE...WITH LIGHT RAIN SHOWERS OR DRIZZLE BEING EXPERIENCED. THE EXCEPTION WILL COME ALONG THE LAKE ONTARIO SHORELINE AND ACROSS THE NORTH COUNTRY WHERE THIS REGION WILL REMAIN NORTH OF THE SFC BOUNDARY. TEMPERATURES FOR THE REST OF THE OVERNIGHT...TEMPERATURES WILL REMAIN ABOVE FREEZING ACROSS THE WESTERN COUNTIES WHILE SUB FREEZING CONDITIONS WILL BE FOUND NORTH AND EST OF THE TUG. FOR THURSDAY... MERCURY READINGS WILL GENERALLY BE IN THE 40S WITH THE COLDER AIR NORTH OF THE TUG FINALLY BEING MODIFIED TOWARDS EVENING. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... A VERY COMPLEX WEATHER SCENARIO WILL BE UNFOLDING DURING THIS PERIOD AS THE SOUTHERN STREAM LOW LIFTING INTO THE NORTHEAST CONUS IS INTERCEPTED BY A DEEP UPPER LEVEL TROUGH DROPPING ACROSS THE NORTHERN PLAINS INTO THE GREAT LAKES WITH THE RESULT BEING A DOUBLE SURFACE LOW STRUCTURE ACROSS THE REGION. THE DOMINANT LOW WILL BE ACROSS THE GREAT LAKES...WHILE THE SECONDARY WEAKER LOW RESIDES OFF THE SOUTHERN NEW ENGLAND COAST AT THE START OF THE PERIOD. THE MAIN OCCLUSION WILL BE NORTH OF THE AREA WHICH SHOULD HAVE WESTERN AND CENTRAL NEW YORK IN A RELATIVE LULL IN PRECIPITATION AT THE BEGIN OF THURSDAY NIGHT. LATER THURSDAY NIGHT THERE WILL BE RAPID CYCLONE INTENSIFICATION BOTH AT THE SURFACE AND ALOFT WHICH WILL CORRESPOND WITH INCREASE LAKE ENHANCEMENT OFF LAKE ERIE AND INCREASING ATLANTIC MOISTURE INFLOW...WHICH SHOULD POINT TO THE EXPANSION OF SNOW OR MIXED PRECIPITATION ACROSS EASTERN SECTION ALONG THE INTENSIFYING BAROCLINIC ZONE UNDERNEATH THE DEEPENING COUPLED JET CIRCULATION ALOFT. THE DEEPENING SURFACE LOW WILL BE LIFTING THROUGH SAINT LAWRENCE VALLEY FRIDAY...WITH THE SUGGESTION OF A TROWAL FEATURE DEVELOPING IN ASSOCIATION WITH THE MID LEVEL DEFORMATION ZONE. ORIENTATION OF THIS FEATURE DIFFERS FROM MODEL TO MODEL MAKING THE PLACEMENT OF POTENTIAL HEAVY SNOWFALL AXIS FRIDAY RATHER DIFFICULT. STILL PLENTY OF UNCERTAINTY TO HOW THE SYNOPTIC PORTION OF THIS SYSTEM WILL PLAY OUT PLACING RELATIVE LOW CONFIDENCE IN SNOWFALL FORECAST FOR THE THURSDAY NIGHT AND FRIDAY TIME FRAME. WE ARE LIKELY LOOKING AT A GENERAL ACCUMULATING SNOW SEVERAL INCHES...ALTHOUGH SIGNIFICANT AMOUNTS TO THE LEE OF THE LAKES WILL BE POSSIBLE... ESPECIALLY IF LAKE ENHANCEMENT CAN GET GOING EARLY ENOUGH. STARTING LATE FRIDAY...THE LAKE EFFECT SNOW WILL BEGIN IN EARNEST AS THE FLOW VEERS TO WEST...THEN TO WEST NORTHWEST AND 850 MB TEMPERATURES DROP INTO THE NEGATIVE LOWER TEENS CELSIUS. PLENTY OF SYNOPTIC SCALE MOISTURE WILL BE IN PLACE ALLOWING IMPRESSIVE DEPTH OF FAVORABLE DENDRITIC SNOW GROWTH REGION TO INTERSECT OMEGA MAXIMUM. THIS WOULD SUGGEST THE POTENTIAL FOR HEAVY LAKE SNOWS IN THE TRADITIONAL WEST NORTHWEST FLOW REGIONS SOUTH OF BUFFALO AND WATERTOWN. STRONG WIND FIELDS MAY HAMPER THE ORGANIZED OF PROLONGED LAKE BANDS...BUT THIS CAN BE ADDRESSED IN LATER FORECAST ISSUANCES. LAKE EFFECT SETUP STILL FAR ENOUGH IN ADVANCE TO KEEP HEADLINES OUT OF FORECAST FOR NOW. WINDS MAY BECOME AN ISSUE FRIDAY...ESPECIALLY DOWNWIND OF THE LAKES WITH BUFKIT MOMENTUM TRANSFER SCHEMES SUGGESTING A PERIOD OF SUSTAIN WINDS OVER 25 KNOTS AND GUSTS OVER 40 KNOTS WHICH MAY PROMPT HEADLINES IN LATER FORECASTS AS WELL. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... BY THE END OF THE WEEKEND...AIR MASS STILL LOOKS PLENTY COLD ENOUGH WITH 850 MB TEMPERATURES IN THE NEGATIVE MID TEENS CELSIUS TO MAINTAIN THE POTENTIAL FOR LINGERING LAKE SNOWS SOUTHEAST OF THE LAKES. SOME SUGGESTION THAT INVERSION HEIGHTS WILL BE LOWERING... THEREFORE THE INTENSITY OF THE LAKE SNOWS IS IN QUESTION AT THIS POINT. LAKE ACTIVITY WILL SHUT DOWN COMPLETELY SUNDAY NIGHT AND MONDAY AS BROAD RIDGE PUSHES ACROSS THE REGION. THE RIDGE LOOKS TO SLIDE EAST MONDAY NIGHT AND A STRONG WARM AIR ADVECTION PATTERN SETS UP BEHIND IT AND AHEAD OF AN APPROACHING ELONGATED COLD FRONT. INCREASE LOW LEVEL MOISTURE INFLOW AHEAD OF THIS FRONT WILL INCREASE THE THREAT FOR SNOW IN THE MONDAY NIGHT AND TUESDAY TIME FRAME... WITH THE ADDED LAKE COMPONENT AS COLDER AIR SPILLS BACK ACROSS THE LOWER LAKES. AIR MASS LOOKS COLD ENOUGH WITH ENOUGH SYNOPTIC SCALE MOISTURE TO REGENERATE WEST NORTHWEST FLOW LAKE SNOWS FOR TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... RAIN WILL BE FOUND ACROSS ALL OF WESTERN NEW YORK THROUGH THE OVERNIGHT WITH CIGS DETERIORATING TO IFR LEVELS. FOR THE EASTERN LAKE ONTARIO REGION...LOW LEVEL COLD AIR BEING FED SOUTH FROM THE ST LAWRENCE VALLEY WILL RESULT IN A MIXED BAG OF WINTRY PCPN INCLUDING SOME ICE FOR KART. SIGNIFICNAT ICING WILL BE POSSIBLE FOR THIS SITE AND COULD SERIOUSLY AFFECT COMMERCIAL AIR TRAFFIC AND LOCAL OPERATIONS. IFR CIGS SHOULD BE IN PLACE FOR THE WESTERN NY TAF SITES BY THURSDAY DAYBREAK WHILE MVFR CIGS WILL MOVE ACROSS KART. THESE CIGS WILL BE WIDESPREAD THROUGH EARLY THURSDAY AFTERNOON BEFORE LOWER ELEVATIONS POSSIBLY IMPROVE TO MVFR LATER IN THE DAY. HIGHER TERRAIN SHOULD STAY LOCKED INTO IFR THROUGH THE AFTERNOON WITH STRATUS NEAR THE HILLTOPS IN SOME LOCATIONS. OUTLOOK... THURSDAY NIGHT THROUGH FRIDAY...MVFR TO IFR WITH RAIN CHANGING TO SNOW. FRIDAY NIGHT AND SATURDAY MVFR IN CHC SNOW...HEAVIER SNOW LIKELY SOUTHEAST OF THE LAKES WITH IFR CONDITIONS. SUNDAY...MVFR TO VFR IN LINGERING SNOW SHOWERS. MONDAY...MAINLY VFR. && .MARINE... AS EASTERLY WINDS INCREASE IN SPEED OVERNIGHT WINDS AND WAVES WILL RISE ABOVE SCA CRITERIA...AND WILL ISSUE A SMALL CRAFT FOR THE WESTERN HALF OF LAKE ONTARIO FOR LATE THIS EVENING THROUGH THURSDAY. MUCH COLDER AIR WILL SURGE ACROSS THE RELATIVELY WARM LAKE WATERS THURSDAY NIGHT AND FRIDAY. THIS WILL PROMOTE STRONG MIXING WITHIN THE LOWER LEVELS OF THE ATMOSPHERE...RESULTING IN A CHANCE FOR GALE FORCE WINDS THURSDAY NIGHT AND FRIDAY. WILL ISSUE A GALE WATCH FOR LAKE ERIE STARTING LATE THURSDAY NIGHT THROUGH FRIDAY. WINDS ON LAKE ONTARIO WILL INCREASE LATER IN THE DAY FRIDAY...WITH WINDS NEARING GALE FORCE LATE FRIDAY AFTERNOON. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NYZ006>008. MARINE...GALE WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR LEZ040-041. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LOZ042-043. && $$ SYNOPSIS...THOMAS NEAR TERM...HITCHCOCK/THOMAS SHORT TERM...TMA LONG TERM...TMA AVIATION...HITCHCOCK/RSH MARINE...THOMAS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1235 AM EST THU JAN 12 2012 .SYNOPSIS... A STORM SYSTEM WILL BRING PRECIPITATION TONIGHT INTO THURSDAY. EAST OF INTERSTATE 81...ESPECIALLY AT HIGHER ELEVATIONS...THE PRECIPITATION MAY BEGIN AS A WINTRY MIX OF FREEZING RAIN...SLEET...AND SNOW. THE REMAINDER OF THE REGION WILL GENERALLY HAVE JUST A COLD RAIN. HOWEVER...A COLD FRONT WILL SWEEP THROUGH LATE THURSDAY NIGHT INTO FRIDAY MORNING...RESULTING IN SNOW SHOWERS DURING THE DAY FRIDAY. COURTESY OF LAKE EFFECT...SNOW SHOWERS CONTINUE INTO SATURDAY FOR MUCH OF THE REGION. && .NEAR TERM /THROUGH TODAY/... 1030 PM UPDATE...NO CHANGES TO THE PREVIOUS FORECAST. UPDATE EARLIER TO REMOVE SNOWFALL AMOUNTS LOOKS TO BE ON TRACK WITH JUST A FEW REPORTS OF A FEW FLAKES AT THE ONSET. WE ARE MOSTLY SEEING SLEET OR RAIN...WITH SOME POCKETS OF FREEZING RAIN. AS THE PRECIPITATION MOVES FARTHER NORTH AND EAST AND ENCOUNTERS SOME COLDER SURFACE TEMPS AND LOWER DEWPOINTS...FREEZING RAIN WILL BECOME MORE LIKELY AND THE ADVISORY CURRENTLY IN PLACE COVERS THIS. I WAS TEMPTED TO DROP MADISON...CHENANGO...PIKE...AND WAYNE COUNTIES FROM THE ADVISORY WITH MOST MESONET SITES SHOWING TEMPS IN THE MID 30S. DECIDED TO HOLD OFF BECAUSE WE HAVE GOTTEN A FEW REPORTS OF FREEZING RAIN BUT THEY HAVE BEEN CONFINED TO ELEVATIONS CLOSER TO 2000 FEET IN THESE AREAS. WITH THE UPDATE TO THE ADVISORY...TRIED TO STRESS HIGHER ELEVATIONS HERE FOR THE FREEZING RAIN POTENTIAL. FARTHER NORTH AND EAST IN OUR NORMALLY COLDER SPOTS OF ONEIDA...OTSEGO...DELAWARE AND SULLIVAN COUNTIES...FREEZING RAIN POTENTIAL IS MUCH HIGHER AND I REMOVED ANY HIGHER ELEVATION WORDING BECAUSE IT WILL BE MORE WIDESPREAD HERE AND NOT JUST CONFINED TO THE HIGHEST TERRAIN. A GOOD EXAMPLE IS MONTICELLO WHICH HAS DROPPED FROM 36 TO 32 AND IS PROBABLY SEEING SOME FREEZING RAIN ATTM. THE PREVIOUS AFD IS BELOW... 730 PM UPDATE...OVERALL FORECAST EVOLUTION IS IN GOOD SHAPE. PRECIPITATION IS ADVANCING ACROSS THE SOUTHERN THIRD OF THE CWA AS WE SPEAK. PREFER THE NAM/RUC FORECAST SOUNDINGS WHICH SHOW THE PRECIPITATION STARTING OFF MOSTLY AS ALL RAIN IN THE LOWER ELEVATIONS...WITH A MIX OF ANYTHING FROM RAIN TO SLEET OR EVEN A FEW SNOWFLAKES ABOVE 1200 FEET. TAMDAR SOUNDINGS OUT OF SYRACUSE SHOW THIS NICELY WITH PLENTY OF DRY AIR IN THE MID LEVELS ALLOWING FOR SOME QUICK WET BULBING...BEFORE OUR WARM NOSE PUNCHES IN AROUND 850 MB. THIS PUNCH OF WARMER AIR WILL TRANSITION MOST OF THE AREA TO PLAIN RAIN. THE EXCEPTION WILL BE FARTHER EAST AND NORTH...WHERE WE HAD ADVISORIES IN PLACE...WHERE THE MIX OF SLEET/SNOW...AND EVEN SOME FREEZING RAIN WILL LINGER MUCH LONGER. MAIN ADJUSTMENT TO THIS PACKAGE IS TO LOWER SNOWFALL AMOUNTS. WHILE SOME SNOW IS POSSIBLE NEAR THE ONSET AND SHORTLY THEREAFTER...FEEL THE WARM NOSE DEPICTED ON THE RUC AND NAM WILL BE ENOUGH TO HELP US MIX WITH SLEET QUICKLY...THUS CUTTING DOWN SNOWFALL AMOUNTS. AT THIS POINT SEE NOTHING MORE THAN A COATING OF SNOWFALL OVER THE FAR EAST...WITH OUR ADVISORIES JUSTIFIED BY A COMBINATION OF SLEET AND ESPECIALLY FREEZING RAIN. AFTER 07Z ENOUGH WARM AIR ALOFT WILL MOVE INTO THE AREA THAT IT WILL BE JUST A RAIN OR FREEZING RAIN SITUATION...WITH ALL THE EMPHASIS SHIFTING TO OUR SURFACE TEMPS. OUR NORMALLY COLDER SPOTS FROM NORTHERN OTSEGO COUNTY INTO THE MOHAWK VALLEY REMAIN AT THE HIGHEST RISK FOR A PROLONGED PERIOD OF LIGHT FREEZING RAIN. THIS IS WELL SUPPORTED BY OBS IN THE CENTRAL MOHAWK VALLEY THAT ARE ALREADY BELOW FREEZING...WITH DEW-POINTS IN THE LOWER TO MIDDLE 20S. LOOK FOR OUR NEXT UPDATE AROUND 10 PM. IF WE CONTINUE TO SEE TEMPS ABOVE FREEZING IN NORTHERN PA...WE MAY BE ABLE TO TRIM BACK OUR ADVISORY FROM SOUTH TO NORTH. 415 PM UPDATE...TREND FOR A WARMER INCIPIENT BOUNDARY LAYER CONTINUES IN THE MODELS...AS SYSTEM MOVES IN TONIGHT. THUS I DO NOT SEE A NEED FOR ANY FURTHER EXPANSION OF CURRENT WINTER WEATHER ADVISORY...WHICH INCLUDES COUNTIES EAST OF INTERSTATE 81. FOR COUNTIES ALONG AND WEST OF INTERSTATE 81...HIGH CONFIDENCE NOW THAT PRECIPITATION TYPE WILL BE ALL RAIN...WITH PERHAPS ONLY A LITTLE BRIEF SLEET BUT WITH TEMPERATURES STAYING ABOVE FREEZING. AND OF THE WINTER WEATHER ADVISORY COUNTIES...TRANSITION TO PLAIN RAIN WILL OCCUR EARLY FOR ALL BUT ONEIDA/DELAWARE/OTSEGO...SO I MOVED UP THE END TIME FOR THOSE ZONES TO 6 AM. FOR THE EARLIER ENDING ZONES...ICE AND SNOW ACCUMULATIONS LOOK TO BE FAIRLY LIGHT AND MAINLY AT HIGHER ELEVATIONS. MANY VALLEY LOCATIONS MAY GET THROUGH WITH ONLY PLAIN RAIN OR A LITTLE LIGHT SLEET. COLD AIR WILL LINGER LONGER IN THE NORTHEASTERN ZONES COURTESY OF COLD AIR DAMMING...SO WINTRY MIX WILL LAST INTO THE MORNING. WE WILL HAVE TO WATCH CLOSELY FOR ICE ACCUMULATIONS IN EXCESS OF A QUARTER INCH...IN PARTICULAR TOWARDS THE MOHAWK VALLEY/SOUTHERN TUG HILL PLATEAU...SHOULD THE COLD AIR TAKE LONG TO SCOUR OUT. SNOW ACCUMULATIONS MEANWHILE WILL BE OF HIGH WATER CONTENT...GENERALLY 1 TO 3 INCHES AND MAINLY AT HIGHER ELEVATIONS. WHATEVER THE TYPE...FOR THE AREA IN GENERAL RAW PRECIPITATION AMOUNTS WILL RANGE FROM A HALF INCH OR SO IN THE WEST- NORTHWEST...TO ALMOST AN INCH IN THE SOUTHEAST. AFTER A BRIEF DIP IN TEMPERATURES EARLY THIS EVENING...LOOKING FOR STEADY TO SLOWLY RISING TEMPERATURES OVERNIGHT. FINGER LAKES...SOUTHERN TIER OF NY...AND MOST OF NORTHEAST PA WILL EVENTUALLY GET INTO THE 40S THURSDAY. DEEPER MOISTURE EXITS WITH THE OCCLUDED FRONT MIDDAY THURSDAY...LEAVING LIGHT SHOWERS OR PERHAPS DRIZZLE IN THE AFTERNOON TO EVENING. BOUNDARY LAYER WILL BE SLOW TO COOL THURSDAY NIGHT...UNTIL ARRIVAL OF STRONG NEGATIVELY TILTED COLD FRONT TOWARDS DAWN FRIDAY. SO CHANGEOVER OF ANY REMAINING LIGHT RAIN SHOWERS TO SNOW...WILL BE GRADUAL. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... UPDATED AS OF 4 PM WED... MODEL CONSENSUS IS FAIRLY GOOD ON SYSTEM EVOLUTION THIS PD. A STG COLD FRONT IS SLATED TO CROSS THE FA FROM SW TO NE FRI AM...GENERALLY IN THE 12-15Z TIME FRAME. QG FORCING IS PRETTY POTENT WITH THIS FRNT...AS A HEALTHY UPPER-LVL WAVE ACCOMPANIES IT...SO MOST SXNS SHOULD SEE SHRA/SHSN WITH THE FROPA. INITIALLY...THE DEEP-LYRD FLOW IS PROGGED TO BE SWLY FRI AFTN POST-FROPA...SO AS THE LAKES BEGIN TO FIRST RESPOND TO THE INCOMING COLD AIR...THE BRUNT OF THE LES SHOULD STAY N AND W OF THE CWA...WITH JUST SCTD -SHSN/FLRYS ANTICIPATED IN CNY/NRN TIER PA. WINDS SHOULD BE STG AND GUSTY FRI AFTN...WITH DECENT ISALLOBARIC FORCING AND GOOD MOMENTUM TRANSFER CONDITIONS AT PLAY. ADVSY LVL WIND GUSTS ARE NOT OUT OF THE QUESTION (35-45 KT)...SPCLY OUR NRN/WRN ZNS...AND LATER SHIFTS WILL BE TAKING A CLOSER LOOK AT THIS. FRI NGT AND SAT...AS A SECONDARY SFC TROUGH PUSHES THROUGH...AND ADDITIONAL UPPER-LVL WAVES TRAVERSE THE RGN...THE BLYR FLOW SHOULD VEER MORE INTO A 280-300 VECTOR WITH TIME. THIS SHOULD STEER MORE PERSISTENT LES INTO OUR FA. THE BEST OPPORTUNITY FOR MORE SIG LES MAY BE RESTRICTED TO A RELATIVELY NARROW WINDOW FRI NGT...WHEN THE BEST COMBO OF CYCLONIC FLOW AND DEEPER MOIST/PSBL MULTI-LK INFLUENCE EXISTS. HOWEVER...THE DETRACTING ELEMENTS OF TRANSITIONAL FLOW AND TERRESTRIAL INSTAB FRI EVE ALSO SEEM TO BE THERE. TIME WILL TELL ON HOW THIS ALL SHAKES OUT...BUT WE DO HAVE LIKELY POPS FOR SHSN FROM LATER FRI AFTN INTO EARLY SAT ACROSS MANY OF OUR NRN ZNS. AS WE HEAD THRU THE DAY SAT...THE INVERSION SHOULD LWR SUBSTANTIALLY...WITH THE MOIST SUPPLY ALSO WANING. THUS...MORE PERSISTENT SHSN SHOULD DIMINISH TO SCTD -SHSN/FLRYS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 3 PM UPDATE... SATURDAY NIGHT/SUNDAY...850 TEMPS OF -16C TO -18C AND A NORTHWEST FLOW WILL BE FAVORABLE FACTORS FOR LAKE EFFECT SNOW DURING THIS TIME BUT A LOW INVERSION (4KFT SATURDAY NIGHT THEN LOWERING SUNDAY) ALONG WITH DRY AIR WILL INHIBIT MUCH FROM HAPPENING. STILL WITH COLD AIR IN PLACE EXPECT A FEW FLURRIES OR A BRIEF SNOW SHOWER ESPECIALLY FROM SYRACUSE DOWN THROUGH THE CORTLAND AREA ON A 320 FLOW. SUNDAY NIGHT/MONDAY....HIGH PRESSURE BUILDING SOUTH ACROSS THE AREA WILL KEEP THIS PERIOD DRY AND QUIET. WITH A BETTER SHOT AT A CLEAR SKY SUNDAY NIGHT...MORNING LOWS MONDAY WILL BE IN THE SINGLE DIGITS FOR MOST OF THE AREA WITH READINGS BELOW ZERO OVER THE FAR EAST AND NORTH. TUESDAY/WEDNESDAY....AN AREA OF LOW PRESSURE MOVING THROUGH THE NORTHERN GREAT LAKES STILL LOOKS TO BRING US OUR NEXT SHOT AT SIGNIFICANT PRECIPITATION. BOTH THE EURO AND GFS ARE PRETTY SIMILAR WITH THE TRACK BEING WELL TO OUR NORTH AND WEST...BUT THEY DIFFER ON HOW MUCH WARM AIR IS DRAWN UP AHEAD OF THE SYSTEM. ONE THING IS FOR SURE...THE COLD AIR WHICH WILL BE IN PLACE THIS UPCOMING WEEKEND WILL BE RETREATING OUT TO SEA BUT MANY QUESTIONS REMAIN ON HOW MUCH OF IT REMAINS BEHIND. WITH NO CLEAR-CUT SOLUTION CONTINUED TO PLAY IT A RAIN/SNOW MIX TUESDAY WITH A TRANSITION TO SNOW TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... RAIN AND LIGHT FOG WILL PERSIST OVERNIGHT AND INTO THURSDAY AFTERNOON, KEEPING THE TERMINALS IN MVFR TERRITORY. CEILINGS WILL RANGE FROM 1500 TO 2500 FEET, WITH VISIBILITIES FLUCTUATING BETWEEN 3SM AND P6SM AS RAIN BANDS MOVE IN AND OUT. AT THE HIGHER ELEVATION BGM TERMINAL, BORDERLINE IFR CONDITIONS WILL HOLD THROUGH AT LEAST LATE MORNING. CEILINGS WILL BE BETWEEN 500 AND 1000 FEET WITH VISIBILITIES BETWEEN 2SM AND 6SM. WINDS WILL BE GUSTY THROUGH 9Z, WITH OCCASIONAL EAST-SOUTHEAST GUSTS OF 15 TO 20 KNOTS. WINDS WILL DIE DOWN A BIT TOWARD SUNRISE AS THE PRESSURE GRADIENT SLACKENS. RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS LATE THURSDAY NIGHT OR EARLY FRIDAY MORNING, WITH TEMPO MVFR TO BORDERLINE IFR CONDITIONS POSSIBLE. .OUTLOOK... FRI...GUSTY WINDS AND PSBL RESTRICTIONS IN SHSN...ESPECIALLY KRME/KSYR. FRI NGT/SAT...MVFR/IFR IN LAKE-EFFECT SHSN KSYR/KRME...WITH RESTRICTIONS ALSO PSBL AT KBGM/KITH/KELM. SUN/MON...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR PAZ040-048-072. NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NYZ036-045-062. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ009-037- 046-057. && $$ SYNOPSIS...MDP NEAR TERM...HEDEN/MDP SHORT TERM...MLJ LONG TERM...HEDEN AVIATION...DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1255 PM EST THU JAN 12 2012 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL CAUSE BREEZY WESTERLY WINDS ACROSS THE CAROLINAS AND SOUTHERN VIRGINIA TODAY. A POLAR COLD FRONT WILL CROSS THE REGION TONIGHT. MUCH COOLER AIR WILL SETTLE OVER THE AREA FRIDAY AND LINGER INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1020 AM THURSDAY... DEEP BUT TEMPORARY WEST-SOUTHWESTERLY FLOW OBSERVED OVER CENTRAL NC THIS MORNING AS ONE LOW PRESSURE SYSTEM IS LIFTING TOWARD NEW ENGLAND AND A SECOND CLIPPER LOW IS DIVING THROUGH THE MIDWEST STATES. THE AIRMASS AROUND THE SOUTHEAST IS FAIRLY UNIFORM...SO HIGHS TODAY WILL MOSTLY BE DEPENDING ON MIXING AS GRADIENT WINDS INCREASE AHEAD OF THE APPROACHING DEEP CLIPPER SYSTEM. FORECAST SOUNDINGS SHOW MIXING TO AROUND 900MB...WHICH MAY BE SLIGHTLY UNDERDONE GIVEN THAT WINDS ARE ALREADY INCREASING TO 12-15KT AND WILL EVENTUALLY GUST TO NEAR 25KT THIS AFTERNOON. A RIBBON OF STRATUS TRAPPED BELOW THE SUBSIDENCE INVERSION OVER THE FOOTHILLS AND WESTERN PIEDMONT HAS RESISTED MIXING SO FAR...AND ALSO A LARGE AREA IF STRATUS IS ADVANCING THROUGH UPSTATE SC AND MAY BLEED INTO AREAS NEAR THE YADKIN RIVER. CLOUD COVER WILL BE ADJUSTED OVER THE WESTERN COUNTIES BASED ON SOME OF THE HRRR AVIATION GUIDANCE AND TEMPS MAY ULTIMATELY BE HELD DOWN A COUPLE OF DEGREES IN THE WEST. EXPECT HIGHS OF 58-65 NORTHWEST TO SOUTHEAST. -SMITH AS THE UPPER TROUGH AND SFC COLD FRONT CROSSES THE MTNS THIS EVENING...STRONG FRONTOGENETIC FORCING WITHIN UPPER JET EXIT REGION WILL SUPPORT A BAND OF SHALLOW CONVECTION THAT WILL QUICKLY MOVE EAST ACROSS CENTRAL NC BETWEEN 00 TO 06Z. MOISTURE WILL BE LIMITED WITH EXPECTED SCATTERED SHOWERS TENDING TO DRY UP/DISSIPATE AS THEY ADVANCE EAST OFF THE HIGHER TERRAIN AS FLOW QUICKLY BECOMES WESTERLY WITH STRONG DRY COLD AIR ADVECTION ENSUING. ANY PRECIP WILL BE ALL LIQUID WITH COLD AIR TRAILING THE EXITING SHALLOW MOIST LAYER. SKIES SHOULD CLEAR OFF MIDNIGHT WITH CAA PLUNGING TEMPERATURES DOWN INTO THE LOWER 30S NORTHWEST TO MID/UPPER 30S SOUTHEAST. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... AS OF 315 AM THURSDAY... FRIDAY AND FRIDAY NIGHT: A TIGHT PRESSURE GRADIENT WILL CONTINUE ON FRIDAY BETWEEN THE DEEPENING LOW PRESSURE OVER NEW ENGLAND AND SURFACE HIGH PRESSURE OVER THE GULF COAST STATES. INVERSELY TO TODAY...THESE WINDS WILL EXACERBATE THE BUILDING ARCTIC AIRMASS AS LOW-LEVEL THICKNESSES 12Z FRIDAY MORNING ARE FORECAST TO START OUT 30 METERS BELOW NORMAL...SUPPORTING HIGHS IN THE LOWER 40S NW TO UPPER 40S SOUTHEAST...WITH BLUSTERY WESTERLY WINDS PRODUCING WIND CHILLS OF 35 TO 40. PRESSURE GRADIENT RELAXES FRIDAY EVENING/NIGHT AS LOW OVER NEW ENGLAND CONTINUES TO MOVE AWAY. COLD OVERNIGHT LOWS IN THE IN THE LOWER TO MID 20S. SATURDAY...L/W TROUGH OVER THE EASTERN HALF OF THE U.S WILL MAINTAIN COOLER THAN NORMAL CONDITIONS ACROSS OUR REGION. 850MB THERMAL TROUGH LIES ACROSS THE REGION SATURDAY WITH 850MB TEMPS MINUS 6-MINUS 8 DEGREES C. THICKNESSES 30-35M BELOW NORMAL WHICH WOULD YIELD MAX TEMPS NO HIGHER THAN THE UPPER 30S TO NEAR 40 IN THE PIEDMONT. ADJUSTING FOR POTENTIAL AIR MASS MODIFICATION...EXPECT MAX TEMPS IN THE LOW-MID 40S OVER THE PIEDMONT AND NORTHERN COASTAL PLAIN..AND UPPER 40S ACROSS THE FAR SOUTH. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 315 AM THURSDAY... SATURDAY NIGHT...MODEL GUIDANCE HAS TRENDED FARTHER SOUTH WITH A VORT MAX IN THE NW FLOW TRAVERSING SEWD ON THE BACK SIDE OF THE TROUGH. DUE TO THE MORE SOUTHWARD PATH OF THE VORT MAX INTO THE BASE OF THE UPPER TROUGH OVER OUR REGION...WE HAVE A BETTER CHANCE OF SEEING MORE CLOUDS AND POSSIBLY SOME LIGHT PRECIP. 00Z GFS RH/TEMP/LIFT CROSS SECTION FOR 06Z SUNDAY DOES DEPICT ADEQUATE MOISTURE AND LIFT IN THE FAVORED ICE NUCLEATION REGION TO GENERATE SNOWFLAKES ALOFT. HOWEVER THE LIFT DOES NOT EXTEND DOWN INTO THE LOWEST 8K FT OF THE ATMOSPHERE PLUS THE SUBCLOUD LAYER IS QUITE DRY SUGGESTING A HIGH PROBABILITY OF EVAPORATION. PARTIAL THICKNESSES SUGGEST THAT ANY PRECIP THAT DOES REACH THE SURFACE WOULD BE LIGHT SNOW. SINCE THIS IS THE FIRST ITERATION OF THIS POSSIBLE SCENARIO BY THE MODELS...AND THE NEAR SURFACE CONDITIONS NOT IDEAL FOR PRECIP...WILL REFRAIN FROM MENTIONING PRECIP IN THE FORECAST AT THIS TIME. IF PRECIP WERE TO OCCUR...WOULD EXPECT NOTHING MORE THAN A FEW SNOW FLURRIES...MAINLY LATE SATURDAY EVENING INTO THE OVERNIGHT HOURS. DUE TO THE INCREASE IN CLOUD COVERAGE...EXPECT MIN TEMPS TO BE A COUPLE OF DEGREES WARMER THAN FRIDAY NIGHT. MOST PLACES SHOULD BE IN THE UPPER 20S. SUNDAY INTO MONDAY...STRONG SUBSIDENCE IN THE WAKE OF THE EXITING VORT MAX SUNDAY MORNING WILL LEAD TO CLEARING SKIES WITH SUNNY SKIES EXPECTED AREAWIDE BY EARLY AFTERNOON. NW FLOW AT 850MB IN THE WAKE OF THE SYSTEM SUNDAY DEPICT NEUTRAL ADVECTION AT THIS TIME. LINGERING EFFECTS OF 850MB THERMAL TROUGH OVER THE REGION SHOULD YIELD MAX TEMPS SLIGHTLY BELOW NORMAL. AFTERNOON TEMPS IN THE MID-UPPERS 40S PROJECTED. SURFACE RIDGE OVER THE REGION SUNDAY NIGHT SHOULD CREATE IDEAL CONDITIONS FOR RADIATIONAL COOLING. MIN TEMPS MID 20S WITH LOWER 20S POSSIBLE IN THE NORMALLY COLDER LOCALES. MODEST RECOVERY BEGINS MONDAY AS SURFACE RIDGE SHIFTS EAST AND RETURN FLOW COMMENCES LATE IN THE DAY. AIR MASS MODIFICATION SHOULD RESULT IN MAX TEMPS CLOSE TO NORMAL FOR MID JANUARY...UPPER 40S TO THE LOWER 50S. MONDAY NIGHT INTO TUESDAY...MODELS HAVE TRENDED WETTER WITH THIS PARTICULAR MODEL RUN. BOTH THE 00Z GFS AND 00Z ECMWF PAINT LIGHT PRECIP OVER CENTRAL NC MONDAY NIGHT IN THE LOW LEVEL WAA REGIME. ISENTROPIC UPGLIDE APPEARS TO BE BEST IN THE 285-290K LAYER. WHILE CANNOT RULE SPOTTY PRECIP...LOW LEVEL AIR MASS WILL BE QUITE DRY MONDAY WITH DEWPOINTS IN THE TEENS. THUS THE PRECIP GENERATED BY THE MODELS MAY ACTUALLY GO INTO MOISTENING THE SUB CLOUD LAYER TO SATURATION. WILL KEEP POPS BELOW 20 PERCENT BUT DID RAISE MIN TEMPS A COUPLE OF DEGREES DUE TO THICKENING CLOUDS. NEXT MID-UPPER LEVEL S/W IN THE BROAD TROUGH OVER THE EASTERN U.S. PROJECTED TO ADVANCE EAST FROM THE MID MS VALLEY INTO THE OH VALLEY TUESDAY. THIS FEATURE WILL INDUCE WSW FLOW ALOFT. MEANWHILE N-S ORIENTATION OF THE SURFACE RIDGE OFF THE EASTERN SEABOARD YIELDS A LOW LEVEL S-SW FLOW OVER THE CAROLINAS ORIGINATING FROM THE CENTRAL GULF. THIS SUGGEST A SHOT OF LOW LEVEL MOISTURE TRANSPORT INTO OUR REGION AHEAD OF THE S/W AND ATTENDANT SURFACE FRONT. SINCE WE ARE TALKING ABOUT DAY6/7...WILL ADJUST POP ONLY A TAD TO ABOUT 30 PERCENT IN THE WEST AND MAINTAIN A SLIGHT CHANCE IN THE EAST. MODEL TIMING SUGGEST HIGHEST THREAT FOR PRECIP TUESDAY AFTERNOON-EARLY TUESDAY NIGHT. SYSTEM EXITS REGION WEDNESDAY LEADING TO CLEARING SKIES. TEMPS BEHIND FRONT WILL BE SLIGHTLY COOLER BUT NOT OUTRAGEOUSLY COLD SINCE HIGH APPEARS TO BE OF PACIFIC ORIGIN WITH SOME MODIFIED CP INFLUENCE. && .AVIATION /18Z THURSDAY THROUGH MONDAY/... AS OF 1255 PM THURSDAY... STRATUS OVER THE WESTERN PIEDMONT THIS MORNING HAS BEEN SLOW TO LIFT AND SCATTER...SO SOME LOW STRATUS/STRATOCU ARE AFFECTING AREAS IN AROUND THE KINT/KGSO TERMINALS. FURTHER SOUTH...STRATUS OVER SC HAS MOVED RATHER QUICKLY TO THE NORTH-NORTHEAST...AND SOME MVFR CEILINGS OF 2-3KT ARE BEING REPORTED OVER THE SOUTHERN PIEDMONT AND SANDHILLS. DUE TO THIS... THE CURRENT TAF PACKAGE WILL MAINTAIN MVFR CEILINGS AT KGSO/KINT/KFAY INTO THE EVENING HOURS AS INCREASING MOISTURE AND POSSIBLY A FEW SHOWERS ASSOCIATED WITH AN UPPER DISTURBANCE APPROACHING FROM THE NORTHWEST SHOULD KEEP CEILINGS PREDOMINATELY BELOW 3K FT. ANY SHOWERS AND MVFR CEILINGS WILL EVENTUALLY REACH KRDU AND KRWI LATE THIS EVENING...BUT SKIES ARE EXPECTED TO CLEAR FROM WEST TO EAST AFTER MIDNIGHT AS THE AFOREMENTIONED DISTURBANCE SWINGS ACROSS THE AREA. BRISK WEST-SOUTHWESTERLY WINDS OF 12-15KT AND GUSTS INTO THE LOW TO MID 20KT RANGE WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS...SWITCHING TO MORE WESTERLY ON FRIDAY BUT REMAINING GUSTY. OUTLOOK... VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD...OUTSIDE OF A BRIEF PERIOD MVFR CEILINGS SATURDAY NIGHT AS ANOTHER CLIPPER SYSTEM SWINGS THROUGH THE REGION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...CBL/SMITH SHORT TERM...CBL/WSS LONG TERM...WSS AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EST THU JAN 12 2012 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL CAUSE BREEZY WESTERLY WINDS ACROSS THE CAROLINAS AND SOUTHERN VIRGINIA TODAY. A POLAR COLD FRONT WILL CROSS THE REGION TONIGHT. MUCH COOLER AIR WILL SETTLE OVER THE AREA FRIDAY AND LINGER INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1020 AM THURSDAY... DEEP BUT TEMPORARY WEST-SOUTHWESTERLY FLOW OBSERVED OVER CENTRAL NC THIS MORNING AS ONE LOW PRESSURE SYSTEM IS LIFTING TOWARD NEW ENGLAND AND A SECOND CLIPPER LOW IS DIVING THROUGH THE MIDWEST STATES. THE AIRMASS AROUND THE SOUTHEAST IS FAIRLY UNIFORM...SO HIGHS TODAY WILL MOSTLY BE DEPENDING ON MIXING AS GRADIENT WINDS INCREASE AHEAD OF THE APPROACHING DEEP CLIPPER SYSTEM. FORECAST SOUNDINGS SHOW MIXING TO AROUND 900MB...WHICH MAY BE SLIGHTLY UNDERDONE GIVEN THAT WINDS ARE ALREADY INCREASING TO 12-15KT AND WILL EVENTUALLY GUST TO NEAR 25KT THIS AFTERNOON. A RIBBON OF STRATUS TRAPPED BELOW THE SUBSIDENCE INVERSION OVER THE FOOTHILLS AND WESTERN PIEDMONT HAS RESISTED MIXING SO FAR...AND ALSO A LARGE AREA IF STRATUS IS ADVANCING THROUGH UPSTATE SC AND MAY BLEED INTO AREAS NEAR THE YADKIN RIVER. CLOUD COVER WILL BE ADJUSTED OVER THE WESTERN COUNTIES BASED ON SOME OF THE HRRR AVIATION GUIDANCE AND TEMPS MAY ULTIMATELY BE HELD DOWN A COUPLE OF DEGREES IN THE WEST. EXPECT HIGHS OF 58-65 NORTHWEST TO SOUTHEAST. -SMITH AS THE UPPER TROUGH AND SFC COLD FRONT CROSSES THE MTNS THIS EVENING...STRONG FRONTOGENETIC FORCING WITHIN UPPER JET EXIT REGION WILL SUPPORT A BAND OF SHALLOW CONVECTION THAT WILL QUICKLY MOVE EAST ACROSS CENTRAL NC BETWEEN 00 TO 06Z. MOISTURE WILL BE LIMITED WITH EXPECTED SCATTERED SHOWERS TENDING TO DRY UP/DISSIPATE AS THEY ADVANCE EAST OFF THE HIGHER TERRAIN AS FLOW QUICKLY BECOMES WESTERLY WITH STRONG DRY COLD AIR ADVECTION ENSUING. ANY PRECIP WILL BE ALL LIQUID WITH COLD AIR TRAILING THE EXITING SHALLOW MOIST LAYER. SKIES SHOULD CLEAR OFF MIDNIGHT WITH CAA PLUNGING TEMPERATURES DOWN INTO THE LOWER 30S NORTHWEST TO MID/UPPER 30S SOUTHEAST. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... AS OF 315 AM THURSDAY... FRIDAY AND FRIDAY NIGHT: A TIGHT PRESSURE GRADIENT WILL CONTINUE ON FRIDAY BETWEEN THE DEEPENING LOW PRESSURE OVER NEW ENGLAND AND SURFACE HIGH PRESSURE OVER THE GULF COAST STATES. INVERSELY TO TODAY...THESE WINDS WILL EXACERBATE THE BUILDING ARCTIC AIRMASS AS LOW-LEVEL THICKNESSES 12Z FRIDAY MORNING ARE FORECAST TO START OUT 30 METERS BELOW NORMAL...SUPPORTING HIGHS IN THE LOWER 40S NW TO UPPER 40S SOUTHEAST...WITH BLUSTERY WESTERLY WINDS PRODUCING WIND CHILLS OF 35 TO 40. PRESSURE GRADIENT RELAXES FRIDAY EVENING/NIGHT AS LOW OVER NEW ENGLAND CONTINUES TO MOVE AWAY. COLD OVERNIGHT LOWS IN THE IN THE LOWER TO MID 20S. SATURDAY...L/W TROUGH OVER THE EASTERN HALF OF THE U.S WILL MAINTAIN COOLER THAN NORMAL CONDITIONS ACROSS OUR REGION. 850MB THERMAL TROUGH LIES ACROSS THE REGION SATURDAY WITH 850MB TEMPS MINUS 6-MINUS 8 DEGREES C. THICKNESSES 30-35M BELOW NORMAL WHICH WOULD YIELD MAX TEMPS NO HIGHER THAN THE UPPER 30S TO NEAR 40 IN THE PIEDMONT. ADJUSTING FOR POTENTIAL AIR MASS MODIFICATION...EXPECT MAX TEMPS IN THE LOW-MID 40S OVER THE PIEDMONT AND NORTHERN COASTAL PLAIN..AND UPPER 40S ACROSS THE FAR SOUTH. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 315 AM THURSDAY... SATURDAY NIGHT...MODEL GUIDANCE HAS TRENDED FARTHER SOUTH WITH A VORT MAX IN THE NW FLOW TRAVERSING SEWD ON THE BACK SIDE OF THE TROUGH. DUE TO THE MORE SOUTHWARD PATH OF THE VORT MAX INTO THE BASE OF THE UPPER TROUGH OVER OUR REGION...WE HAVE A BETTER CHANCE OF SEEING MORE CLOUDS AND POSSIBLY SOME LIGHT PRECIP. 00Z GFS RH/TEMP/LIFT CROSS SECTION FOR 06Z SUNDAY DOES DEPICT ADEQUATE MOISTURE AND LIFT IN THE FAVORED ICE NUCLEATION REGION TO GENERATE SNOWFLAKES ALOFT. HOWEVER THE LIFT DOES NOT EXTEND DOWN INTO THE LOWEST 8K FT OF THE ATMOSPHERE PLUS THE SUBCLOUD LAYER IS QUITE DRY SUGGESTING A HIGH PROBABILITY OF EVAPORATION. PARTIAL THICKNESSES SUGGEST THAT ANY PRECIP THAT DOES REACH THE SURFACE WOULD BE LIGHT SNOW. SINCE THIS IS THE FIRST ITERATION OF THIS POSSIBLE SCENARIO BY THE MODELS...AND THE NEAR SURFACE CONDITIONS NOT IDEAL FOR PRECIP...WILL REFRAIN FROM MENTIONING PRECIP IN THE FORECAST AT THIS TIME. IF PRECIP WERE TO OCCUR...WOULD EXPECT NOTHING MORE THAN A FEW SNOW FLURRIES...MAINLY LATE SATURDAY EVENING INTO THE OVERNIGHT HOURS. DUE TO THE INCREASE IN CLOUD COVERAGE...EXPECT MIN TEMPS TO BE A COUPLE OF DEGREES WARMER THAN FRIDAY NIGHT. MOST PLACES SHOULD BE IN THE UPPER 20S. SUNDAY INTO MONDAY...STRONG SUBSIDENCE IN THE WAKE OF THE EXITING VORT MAX SUNDAY MORNING WILL LEAD TO CLEARING SKIES WITH SUNNY SKIES EXPECTED AREAWIDE BY EARLY AFTERNOON. NW FLOW AT 850MB IN THE WAKE OF THE SYSTEM SUNDAY DEPICT NEUTRAL ADVECTION AT THIS TIME. LINGERING EFFECTS OF 850MB THERMAL TROUGH OVER THE REGION SHOULD YIELD MAX TEMPS SLIGHTLY BELOW NORMAL. AFTERNOON TEMPS IN THE MID-UPPERS 40S PROJECTED. SURFACE RIDGE OVER THE REGION SUNDAY NIGHT SHOULD CREATE IDEAL CONDITIONS FOR RADIATIONAL COOLING. MIN TEMPS MID 20S WITH LOWER 20S POSSIBLE IN THE NORMALLY COLDER LOCALES. MODEST RECOVERY BEGINS MONDAY AS SURFACE RIDGE SHIFTS EAST AND RETURN FLOW COMMENCES LATE IN THE DAY. AIR MASS MODIFICATION SHOULD RESULT IN MAX TEMPS CLOSE TO NORMAL FOR MID JANUARY...UPPER 40S TO THE LOWER 50S. MONDAY NIGHT INTO TUESDAY...MODELS HAVE TRENDED WETTER WITH THIS PARTICULAR MODEL RUN. BOTH THE 00Z GFS AND 00Z ECMWF PAINT LIGHT PRECIP OVER CENTRAL NC MONDAY NIGHT IN THE LOW LEVEL WAA REGIME. ISENTROPIC UPGLIDE APPEARS TO BE BEST IN THE 285-290K LAYER. WHILE CANNOT RULE SPOTTY PRECIP...LOW LEVEL AIR MASS WILL BE QUITE DRY MONDAY WITH DEWPOINTS IN THE TEENS. THUS THE PRECIP GENERATED BY THE MODELS MAY ACTUALLY GO INTO MOISTENING THE SUB CLOUD LAYER TO SATURATION. WILL KEEP POPS BELOW 20 PERCENT BUT DID RAISE MIN TEMPS A COUPLE OF DEGREES DUE TO THICKENING CLOUDS. NEXT MID-UPPER LEVEL S/W IN THE BROAD TROUGH OVER THE EASTERN U.S. PROJECTED TO ADVANCE EAST FROM THE MID MS VALLEY INTO THE OH VALLEY TUESDAY. THIS FEATURE WILL INDUCE WSW FLOW ALOFT. MEANWHILE N-S ORIENTATION OF THE SURFACE RIDGE OFF THE EASTERN SEABOARD YIELDS A LOW LEVEL S-SW FLOW OVER THE CAROLINAS ORIGINATING FROM THE CENTRAL GULF. THIS SUGGEST A SHOT OF LOW LEVEL MOISTURE TRANSPORT INTO OUR REGION AHEAD OF THE S/W AND ATTENDANT SURFACE FRONT. SINCE WE ARE TALKING ABOUT DAY6/7...WILL ADJUST POP ONLY A TAD TO ABOUT 30 PERCENT IN THE WEST AND MAINTAIN A SLIGHT CHANCE IN THE EAST. MODEL TIMING SUGGEST HIGHEST THREAT FOR PRECIP TUESDAY AFTERNOON-EARLY TUESDAY NIGHT. SYSTEM EXITS REGION WEDNESDAY LEADING TO CLEARING SKIES. TEMPS BEHIND FRONT WILL BE SLIGHTLY COOLER BUT NOT OUTRAGEOUSLY COLD SINCE HIGH APPEARS TO BE OF PACIFIC ORIGIN WITH SOME MODIFIED CP INFLUENCE. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 630 AM THURSDAY... 24-HR TAF PERIOD: LOW-LEVEL MOISTURE HAS SCATTERED OUT ACROSS CENTRAL NC AS VIGOROUS LOW PRESSURE SYSTEM ACCELERATES NORTHEASTWARD AWAY FROM THE AREA. DEEP CYCLONIC FLOW AHEAD OF A DEEPENING LOW PRESSURE SYSTEM MOVING THROUGH THE OHIO AND TN VALLEYS WILL RESULT IN BREEZY SWLY WINDS TODAY WITH SCATTERED STRATOCU CLOUD BASES BETWEEN 3 TO 4KFT. AN ARCTIC COLD FRONT WILL MOVE ACROSS THE AREA BETWEEN 00 TO 06 FRIDAY...PRODUCING A SMALL 3-5 HOUR WINDOW OF MVFR CEILINGS WITH WIDELY SCATTERED TO ISOLATED RAIN SHOWERS. SKIES WILL QUICKLY CLEAR OUT BEHIND THE FRONTAL PASSAGE TONIGHT. LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND IN ASSOC/W A COLD/DRY AIRMASS IN PLACE. BREEZY CONDITIONS CAN BE EXPECTED AGAIN ON FRIDAY WITH WEST-SOUTHWESTERLY WIND GUSTS OF 25 TO 30 MPH EXPECTED. THE ONLY POTENTIAL FOR SUB-VFR CONDITIONS WOULD BE A SHORT PERIOD SATURDAY NIGHT/SUNDAY MORNING IN ASSOC/W A CLIPPER SYSTEM PROGRESSING ACROSS THE AREA IN NW FLOW ALOFT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...CBL/SMITH SHORT TERM...CBL/WSS LONG TERM...WSS AVIATION...CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
944 PM CST FRI JAN 13 2012 .DISCUSSION...BAND OF SNOW IS CURRENTLY MOVING ACROSS CENTRAL NORTH DAKOTA. PRECIPITATION HAS ENDED IN THE WEST. BAND HAS SHOW SOME TENDENCY TO DISSIPATE AS IT TRACKS SOUTH AND EAST. THIS IS WELL DEPICTED IN THE LATEST 00Z NAM AND RUC GUIDANCE. UPDATE INCLUDED A TRY AT POPS IN THREE HOUR BLOCKS THROUGH THE REMAINDER OF THE NIGHT. HIGHEST POPS FROM NOW UNTIL MIDNIGHT...THEN LESSENED POPS AS AREA TRANSITIONS EAST AFTER MIDNIGHT. HAD A REPORT OF AROUND AN INCH AT WILLISTON EARLIER. WOULD THINK THAT MOST AREAS IN CENTRAL NORTH DAKOTA WOULD SEE A HALF INCH OR LESS...WITH A FEW LOCALES FROM A HALF INCH TO AN INCH...AND LIGHTER AMOUNTS EXPECTED OVER FAR EASTERN PORTIONS OF CENTRAL NORTH DAKOTA. SOME MINOR ADJUSTMENTS TO TEMPERATURES AND DEW POINTS WITH TEMPERATURES EXPECTED TO RISE YET THIS EVENING IN THE FAR EAST...BEFORE DROPPING OFF LATE. TEMPERATURES WEST WILL DROP OFF SLOWLY AS CLOUDS CLEAR OUT...BUT WINDS WILL KEEP TEMPERATURES FROM BOTTOMING OUT. && .AVIATION...LOW PRESSURE TROUGH ACROSS CENTRAL NORTH DAKOTA THIS EVENING. MAINLY MVFR CEILINGS ASSOCIATED WITH AN AREA OF SNOW OVER CENTRAL NORTH DAKOTA ALONG THE TROUGH. THIS WILL TRANSLATE EAST THROUGH THE EVENING HOURS. WIND INCREASE FOR A FEW HOURS BEHIND THE TROUGH. SKIES ALREADY CLEARING AT WILLISTON AND DICKINSON...SHOULD CLEAR OVER KMOT AND KBIS FROM 04-06Z AND KJMS AROUND 09Z. WESTERLY FLOW WILL CONTINUE INTO SATURDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TWH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
229 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX FRONTAL SYSTEM WILL LIFT NORTHWARD ACROSS PENNSYLVANIA EARLY TODAY WITH STEADY RAINS TAPERING TO SCATTERED SHOWERS BY THE AFTERNOON. MILD SOUTHWEST WINDS WILL HELP BOOST DAYTIME TEMPERATURES SEVERAL DEGREES ABOVE NORMAL. A VIGOROUS UPPER LEVEL CLOSED LOW AND ASSOCIATED ARCTIC FRONTAL BOUNDARY MOVING THROUGH THE OHIO VALLEY INTO THE NORTHEAST STATES WILL BRING ACCUMULATING SNOWS TO MUCH OF WESTERN AND CENTRAL PENNSYLVANIA LATER TONIGHT INTO EARLY FRIDAY. TEMPERATURES WILL DROP RAPIDLY FROM WEST TO EAST BEHIND STRONG GUSTY WINDS IN THE WAKE OF THE ARCTIC FRONTAL PASSAGE. LAKE EFFECT AND MOUNTAIN SNOW SHOWERS WILL FOLLOW FOR THE END OF THE WEEK AND LAST INTO THE WEEKEND...WITH ADDITIONAL SNOW ACCUMULATION LIKELY. THE COLD AND BRISK WEATHER WILL PERSIST THROUGH THE WEEKEND AS AN UPPER LEVEL TROUGH GRIPS THE EASTERN UNITED STATES. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... RADAR SHOWS AREA OF MOD TO LCLY HVY RNFL PIVOTING NWD ACRS THE CENTRAL MTNS AHEAD OF POTENT SRN STREAM S/W LIFTING THRU THE VIRGINAS INTO SRN PA. MAIN CHANGE TO NEAR TERM FCST WAS TO ADD MENTION OF WINTRY MIX IN THE NRN MTNS AS RUC 925-850MB WET BULBS ARE STILL NEAR 0C. THE ENHANCED PCPN RATES SHOULD AID EVAP COOLING WITH EITHER IP OR FZRA P TYPES GIVEN WARM LYR ALOFT AND SHALLOW COLD AIR IN THE 0-1KM LAYER. && .SHORT TERM /7 AM THIS MORNING THROUGH 6 PM FRIDAY/... WITH WINDS SHIFTING TO THE SW ON THU...MOST OF THE DAY SHOULD BE DRY AFTER MID MORNING. MEAN WHILE A POTENT NRN STREAM CLOSED UPPER TROUGH WILL DIG SEWD FM THE MID MISSOURI RVR VLY ACRS THE MIDWEST STATES. AT THE SFC...A COMPLEX FRONTAL BOUNDARY ADJOINING DOUBLE SFC LOWS OVR OH AND ALONG THE NRN MID-ATLC COAST WILL LIFT NWD THRU PA AND ADJACENT STATES EARLY IN THE DAY...ALLOWING THE AREA TO BREAK INTO THE WARM SECTOR AHEAD OF SHARP ARCTIC FRONT SWEEPING THROUGH THE OH VLY. THE NWD MVMT OF THESE LG SCALE FEATURES SHOULD BRING AN END TO STEADIER WAA PCPN OVRRNG THE RETREATING COLD SECTOR...WITH PCPN BCMG MORE SHOWERY IN NATURE BY THURS AFTN. MILD SSWLY WINDS WILL ADVECT UNSEASONABLY WARM AIR INTO THE REGION HELPING TO PUSH TEMPS 10 TO 15 DEGREES ABOVE AVERAGE. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A *HIGH IMPACT SUB ADVISORY* EVENT LOOKS VERY LIKELY LATE THURSDAY NIGHT THROUGH FRIDAY MORNING...AS ARCTIC AIR ARRIVES PUNCTUATED BY A 2-3 HOUR BURST OF MODERATE TO HEAVY SNOW IN MANY AREAS. 3HR TEMPERATURE DROPS BEHIND THE FRONT OF -15F WILL DROP TEMPS FROM THE MID TO UPPER 30S TO THE LOW TO MID 20S FROM WEST TO EAST... BEGINNING WITH WESTERN SECTIONS 06Z THU AND ENDING WITH LOWER SUSQ BY 15Z. UNTREATED ROADS COULD EXPERIENCE FLASH FREEZES UNDER THESE CONDITIONS. VIGOROUS CLOSED H5 LOW PIVOTS ENEWD FROM IN/KY ACRS W-CENTRAL PA INTO NY STATE THU NIGHT AND FRIDAY. STRONG HEIGHT FALLS AND ENHANCED UVVEL/S VIA LEFT EXIT DYNAMICS ASSOC WITH 125KT UPPER JET ROUNDING THE BASE OF THE CLOSED H5 LOW WILL CONTRIBUTE TO A "BURST" OF PCPN OVR THE ALLEGHENIES AND CENTRAL MTNS. RAIN SHOULD QUICKLY TRANSITION TO SNOW UPON THE ARRIVAL OF MUCH COLDER AIR BEHIND THE SHARP ARCTIC FRONT...PROMOTING STEEP LAPSE RATES AND RAPID COLUMN COOLING. MDL QPFS ARE IN PRETTY GOOD AGREEMENT IN GENERATING 0.25-0.50 INCH LIQUID EQUIVALENTS WHICH WOULD TRANSLATE INTO ADVY TYPE SNOW AMTS FOR MANY AREAS. THEREFORE LIGHT TO MODERATE SNOW POTENTIAL CURRENTLY HIGHLIGHTED IN HWO. AS MENTIONED ABOVE...FALLING TEMPERATURES AND STRONG GUSTY WINDS WILL BE A MAJOR CONCERN WITH THE MODIFIED ARCTIC AIR ARRIVAL. THE LATEST MDL DATA SUGGESTS A PERIOD OF STRONG WIND GUSTS APPROACHING 40KTS WILL BE POSSIBLE ON FRIDAY IN THE WAKE OF THE ARCTIC FROPA. STRONG WINDS ALSO HIGHLIGHTED IN THE HWO AND WIND ADVY MAY BE NEEDED. THE STRONG WINDS COMBINED WITH THE ARRIVAL OF SHARPLY COLDER AIR WILL DROP WIND CHILLS INTO THE SINGLE DIGITS OVR THE NORTHERN AND WESTERN MTNS. FINALLY...YET ANOTHER POTENTIAL HAZARD TO CONSIDER LATER IN THE PD WILL BE LAKE EFFECT SNOWS FRI-SUN. A FAVORABLE CROSS-LAKE FETCH SHOULD SET-UP IN THE WAKE OF THE DEEP LOW LIFTING NEWD THRU THE ST LAWRENCE VLY ON DAY 3...WITH SOME ADDITIONAL LIFT LKLY IN ADVANCE OF A REINFORCING S/WV TROUGH ROTATING ACRS THE GRT LKS. THE COLD WNWLY FLOW REGIME WILL ENCOURAGE NMRS LAKE EFFECT SNOW SHOWERS/BANDS WITH MODERATE ACCUMS POSSIBLE DOWNWIND OF LAKE ERIE OVR THE NW SNOWBELT AND ON THE RIDGES OF THE LAUREL HIGHLANDS. AFTER A MILD DAY ON THURSDAY...TEMPERATURES WILL AVG BELOW NORMAL THROUGH THE REMAINDER OF THE PD. THE LW TROUGH IS FCST TO LIFT OUT OF THE NE STATES BY EARLY NEXT WEEK. THIS SHOULD LEAD TO A MODERATION IN TEMPS AS S/WV RIDGE SLIDES EWD FM THE MIDWEST/GRT LKS. MEDIUM RANGE MDL AND ENSEMBLE GUID SHOWS A N-S SFC RIDGE MIGRATING EWD OFF THE ECOAST BY NEXT TUES. THIS FEATURE SHOULD PROVIDE FAIR AND DRY WEATHER TO START NEXT WEEK BEFORE RETURN FLOW AND APPROACHING FRONT BRING THE NEXT THREAT OF PCPN AROUND MID- WEEK/JANUARY 18TH. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... WIDESPREAD IFR CIGS AND RAIN EXPECTED EARLY THIS MORNING AS LOW PRESSURE LIFTS NORTHWARD THRU THE STATE. THE HEAVIEST RAIN AND LLWS IS ASSOCIATED WITH A LOW LVL JET. THIS FEATURE HAS ALREADY CLEARED THE S TIER COUNTIES AT 07Z...AND SHOULD LIFT NORTH OF THE ENTIRE STATE BY DAWN. CONDS WILL BEGIN TO IMPROVE BY LATE THIS MORNING AND AFTN...AS LOW PRESSURE DEPARTS THE AREA. THE IMPROVEMENT WILL BE MOST PRONOUNCED ACROSS THE LOWER ELEVATIONS OF SE PA...WHERE VFR CONDS APPEAR LIKELY BY AFTN. RESIDUAL LOW LVL MOISTURE ASCENDING THE W MTNS MAY RESULT IN PERSISTENT LOW CIGS AT BFD AND JST. A SHARP COLD FRONT WILL SWEEP INTO THE REGION TONIGHT...BRINGING A PERIOD OF RAIN...CHANGING TO WINDBLOWN SNOW OVR THE W MTNS. OUTLOOK... FRI...WINDY WITH MVFR CIGS/SNOW SHOWERS W MTNS. SAT...MVFR CIGS/SNOW SHOWERS POSSIBLE W MTNS. SUN-MON...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...DEVOIR/MARTIN LONG TERM...RXR AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1247 AM EST THU JAN 12 2012 .SYNOPSIS... A COMPLEX FRONTAL SYSTEM WILL LIFT NORTHWARD ACROSS PENNSYLVANIA EARLY TODAY WITH STEADY RAINS TAPERING TO SCATTERED SHOWERS BY THE AFTERNOON. MILD SOUTHWEST WINDS WILL HELP BOOST DAYTIME TEMPERATURES SEVERAL DEGREES ABOVE NORMAL. A VIGOROUS UPPER LEVEL CLOSED LOW AND ASSOCIATED ARCTIC FRONTAL BOUNDARY MOVING THROUGH THE OHIO VALLEY INTO THE NORTHEAST STATES WILL BRING ACCUMULATING SNOWS TO MUCH OF WESTERN AND CENTRAL PENNSYLVANIA LATER TONIGHT INTO EARLY FRIDAY. TEMPERATURES WILL DROP RAPIDLY FROM WEST TO EAST BEHIND STRONG GUSTY WINDS IN THE WAKE OF THE ARCTIC FRONTAL PASSAGE. LAKE EFFECT AND MOUNTAIN SNOW SHOWERS WILL FOLLOW FOR THE END OF THE WEEK AND LAST INTO THE WEEKEND...WITH ADDITIONAL SNOW ACCUMULATION LIKELY. THE COLD AND BRISK WEATHER WILL PERSIST THROUGH THE WEEKEND AS AN UPPER LEVEL TROUGH GRIPS THE EASTERN UNITED STATES. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... RADAR SHOWS AREA OF MOD TO LCLY HVY RNFL PIVOTING NWD ACRS THE CENTRAL MTNS AHEAD OF POTENT SRN STREAM S/W LIFTING THRU THE VIRGINAS INTO SRN PA. MAIN CHANGE TO NEAR TERM FCST WAS TO ADD MENTION OF WINTRY MIX IN THE NRN MTNS AS RUC 925-850MB WET BULBS ARE STILL NEAR 0C. THE ENHANCED PCPN RATES SHOULD AID EVAP COOLING WITH EITHER IP OR FZRA P TYPES GIVEN WARM LYR ALOFT AND SHALLOW COLD AIR IN THE 0-1KM LAYER. && .SHORT TERM /7 AM THIS MORNING THROUGH 6 PM FRIDAY/... WITH WINDS SHIFTING TO THE SW ON THU...MOST OF THE DAY SHOULD BE DRY AFTER MID MORNING. MEAN WHILE A POTENT NRN STREAM CLOSED UPPER TROUGH WILL DIG SEWD FM THE MID MISSOURI RVR VLY ACRS THE MIDWEST STATES. AT THE SFC...A COMPLEX FRONTAL BOUNDARY ADJOINING DOUBLE SFC LOWS OVR OH AND ALONG THE NRN MID-ATLC COAST WILL LIFT NWD THRU PA AND ADJACENT STATES EARLY IN THE DAY...ALLOWING THE AREA TO BREAK INTO THE WARM SECTOR AHEAD OF SHARP ARCTIC FRONT SWEEPING THROUGH THE OH VLY. THE NWD MVMT OF THESE LG SCALE FEATURES SHOULD BRING AN END TO STEADIER WAA PCPN OVRRNG THE RETREATING COLD SECTOR...WITH PCPN BCMG MORE SHOWERY IN NATURE BY THURS AFTN. MILD SSWLY WINDS WILL ADVECT UNSEASONABLY WARM AIR INTO THE REGION HELPING TO PUSH TEMPS 10 TO 15 DEGREES ABOVE AVERAGE. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A *HIGH IMPACT SUB ADVISORY* EVENT LOOKS VERY LIKELY LATE THURSDAY NIGHT THROUGH FRIDAY MORNING...AS ARCTIC AIR ARRIVES PUNCTUATED BY A 2-3 HOUR BURST OF MODERATE TO HEAVY SNOW IN MANY AREAS. 3HR TEMPERATURE DROPS BEHIND THE FRONT OF -15F WILL DROP TEMPS FROM THE MID TO UPPER 30S TO THE LOW TO MID 20S FROM WEST TO EAST... BEGINNING WITH WESTERN SECTIONS 06Z THU AND ENDING WITH LOWER SUSQ BY 15Z. UNTREATED ROADS COULD EXPERIENCE FLASH FREEZES UNDER THESE CONDITIONS. VIGOROUS CLOSED H5 LOW PIVOTS ENEWD FROM IN/KY ACRS W-CENTRAL PA INTO NY STATE THU NIGHT AND FRIDAY. STRONG HEIGHT FALLS AND ENHANCED UVVEL/S VIA LEFT EXIT DYNAMICS ASSOC WITH 125KT UPPER JET ROUNDING THE BASE OF THE CLOSED H5 LOW WILL CONTRIBUTE TO A "BURST" OF PCPN OVR THE ALLEGHENIES AND CENTRAL MTNS. RAIN SHOULD QUICKLY TRANSITION TO SNOW UPON THE ARRIVAL OF MUCH COLDER AIR BEHIND THE SHARP ARCTIC FRONT...PROMOTING STEEP LAPSE RATES AND RAPID COLUMN COOLING. MDL QPFS ARE IN PRETTY GOOD AGREEMENT IN GENERATING 0.25-0.50 INCH LIQUID EQUIVALENTS WHICH WOULD TRANSLATE INTO ADVY TYPE SNOW AMTS FOR MANY AREAS. THEREFORE LIGHT TO MODERATE SNOW POTENTIAL CURRENTLY HIGHLIGHTED IN HWO. AS MENTIONED ABOVE...FALLING TEMPERATURES AND STRONG GUSTY WINDS WILL BE A MAJOR CONCERN WITH THE MODIFIED ARCTIC AIR ARRIVAL. THE LATEST MDL DATA SUGGESTS A PERIOD OF STRONG WIND GUSTS APPROACHING 40KTS WILL BE POSSIBLE ON FRIDAY IN THE WAKE OF THE ARCTIC FROPA. STRONG WINDS ALSO HIGHLIGHTED IN THE HWO AND WIND ADVY MAY BE NEEDED. THE STRONG WINDS COMBINED WITH THE ARRIVAL OF SHARPLY COLDER AIR WILL DROP WIND CHILLS INTO THE SINGLE DIGITS OVR THE NORTHERN AND WESTERN MTNS. FINALLY...YET ANOTHER POTENTIAL HAZARD TO CONSIDER LATER IN THE PD WILL BE LAKE EFFECT SNOWS FRI-SUN. A FAVORABLE CROSS-LAKE FETCH SHOULD SET-UP IN THE WAKE OF THE DEEP LOW LIFTING NEWD THRU THE ST LAWRENCE VLY ON DAY 3...WITH SOME ADDITIONAL LIFT LKLY IN ADVANCE OF A REINFORCING S/WV TROUGH ROTATING ACRS THE GRT LKS. THE COLD WNWLY FLOW REGIME WILL ENCOURAGE NMRS LAKE EFFECT SNOW SHOWERS/BANDS WITH MODERATE ACCUMS POSSIBLE DOWNWIND OF LAKE ERIE OVR THE NW SNOWBELT AND ON THE RIDGES OF THE LAUREL HIGHLANDS. AFTER A MILD DAY ON THURSDAY...TEMPERATURES WILL AVG BELOW NORMAL THROUGH THE REMAINDER OF THE PD. THE LW TROUGH IS FCST TO LIFT OUT OF THE NE STATES BY EARLY NEXT WEEK. THIS SHOULD LEAD TO A MODERATION IN TEMPS AS S/WV RIDGE SLIDES EWD FM THE MIDWEST/GRT LKS. MEDIUM RANGE MDL AND ENSEMBLE GUID SHOWS A N-S SFC RIDGE MIGRATING EWD OFF THE ECOAST BY NEXT TUES. THIS FEATURE SHOULD PROVIDE FAIR AND DRY WEATHER TO START NEXT WEEK BEFORE RETURN FLOW AND APPROACHING FRONT BRING THE NEXT THREAT OF PCPN AROUND MID- WEEK/JANUARY 18TH. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... WIDESPREAD MVFR/IFR EXPECTED OVERNIGHT INTO THURSDAY AS THE SFC LOW APPROACHES AND MOVES THRU. I DID KNOCK THE SFC WINDS DOWN AS STRONG COLD AIR DAMMING IS LEADING TO A VERY STABLE BOUNDARY LAYER AND CAPPING WIND IN THE 10-15 MPH RANGE FOR THE MOST PART. THIS COULD PROMOTE SOME LLWS AS A 30-50KT LOW LEVEL JET ROARS IN OVERNIGHT. CONDITIONS WILL BEGIN TO IMPROVE THURSDAY MORNING AND AFTERNOON AS LOW PRESSURE DEPARTS THE AREA. GUIDANCE HINTS AT A SECOND SPOKE OF ENERGY ROTATING AROUND THE UPPER-LOW AND PUSHING A BIT MORE PRECIP ACROSS AREA THURS NIGHT ALONG AND IN THE WAKE OF A RELATIVELY STRONG COLD FRONT. PERIODS OF MVFR TO IFR IN SNOW WILL BE LIKELY...ESPECIALLY ACROSS THE NRN AND WRN MTNS OF PA. NW FLOW WILL SET UP FRI INTO SAT BEHIND DEPARTING SYSTEM...WHICH WILL CAUSE SOME LAKE-EFFECT/UPSLOPE SNOW SHOWERS ACROSS MAINLY THE NORTH AND WEST. OUTLOOK... THU...LOW PRESSURE DEPARTS AREA. DEVELOPING UPSLOPE FLOW MAY HOLD MVFR CONDS NORTH AND WEST. FRI-SAT...NW FLOW WITH MVFR POSS IN SCTD -SHSN MAINLY NORTH AND WEST. SUN-MON...GENERALLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...DEVOIR/MARTIN LONG TERM...RXR AVIATION...LA CORTE
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
750 PM CST FRI JAN 13 2012 .DISCUSSION.../ISSUED AT 750 PM CST/ AREA OF LIGTH SNOW IN THE JAMES VALLEY CONTINUES TO FILL IN ASSOCIATED WITH SOME 800-900MB FRONTOGENESIS. LATEST RUC SHOWS THAT THIS TREND SHOULD CONTINUE THROUGH 06Z...SPREADING INTO THE I-29 CORRIDOR...THEN PULLING EASTWARD INTO MN AND IA AFTER 06Z THEN EAST OF THE FORECAST AREA BY 12Z. AMOUNTS STILL LOOK TO BE RATHER LIGHT WITH ONE HALF INCH OR LESS EXPECTED. OTHERWISE...STEADY TO SLOWLY RISING TEMPERATURES OVERNIGHT AS FORECAST EARLIER STILL LOOK ON TRACK. && .PREVIOUS DISCUSSION.../ISSUED AT 300 PM CST/ LATEST WATER VAPOR LOOP SHOWING A FAIRLY STRONG WAVE DIGGING INTO EASTERN MONTANA LATE THIS AFTERNOON WHICH WILL BRING THE SHOT OF LIGHT SNOW TO THE AREA TONIGHT. STRONGER BAROCLINICITY CONFINED TO THE LOWEST LEVELS OF THE ATMOSPHERE AND DO NOT EXPECT THIS TO PLAY A BIG ROLE IN PRECIPITATION PRODUCTION. HIGHER UP...AROUND 700MB...NOT MUCH OF A THERMAL GRADIENT SO AT LEAST WITH THIS EVENT PLANNING ON FOLLOWING THE UPPER LEVEL PV ADVECTION AS WELL AS THE 750-650MB THETA E RIDGING. THIS WILL BRING A CHANCE FOR SNOW INTO CENTRAL SOUTH DAKOTA BETWEEN 0Z AND 3Z WITH AN INCREASING CHANCE ACROSS CENTRAL PARTS OF THE CWA FROM ABOUT 3Z THROUGH 9Z...THEN LIKELY PEELING INTO NORTHWEST IOWA FROM ABOUT 6Z THROUGH 12Z. NOT PLANNING ON TOO MUCH ACCUMULATION WITH MOST LOCATIONS AN INCH OR LESS. TEMPERATURES WILL REMAIN STEADY TO RISING THROUGH THE NIGHT AS WELL WITH MORNING TEMPERATURES ABOUT 20 DEGREES WARMER THAN THIS MORNING. BY SATURDAY THE BULK OF THE ACTIVITY SHOULD BE EAST OF THE AREA WITH A MARGINALLY BREEZY NORTHWEST DEVELOPING. HIGHS MOSTLY UNCHANGED FROM EARLIER...RANGING FROM NEAR 30 IN THE NORTHERN CWA TO THE UPPER 30S IN THE SOUTH. A SURFACE RIDGE SLIDES QUICKLY TO THE EAST ON SATURDAY NIGHT...WITH A SOUTHERLY FLOW RETURNING TO THE AREA DURING THE NIGHT TIME HOURS OUT AHEAD OF A TROUGH PUSHING OUT OF THE NORTHERN ROCKIES. WITH THIS...TEMPERATURES WILL BE TRICKY ON SATURDAY NIGHT...INITIALLY DROPPING PRETTY QUICKLY...THEN STEADYING OUT AND RISING IN SOME AREAS OVERNIGHT WITH LOW LEVEL WARM AIR ADVECTION AND AN INCREASING GRADIENT. LOWS EARLY LOOKING TO BE IN THE UPPER TEENS TO LOWER 20S. SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVERAL OUT AHEAD OF THE APPROACHING SURFACE TROUGH. THOUGH WITH SOME MODEL DIFFERENCES...MIXING LOOKS TO BE AROUND 925 MB...WHERE TEMPERATURES WILL BE APPROXIMATELY IN THE RANGE OF 1 TO 7 DEGREES C FROM NORTH TO SOUTH...AND HIGHS WILL BE FROM LOWER 40S NORTH OF THE INTERSTATE 90 CORRIDOR TO AROUND 50 FROM LAKE ANDES TO SIOUX CITY TO STORM LAKE. COLD FRONT DROPS SOUTHWARD ACROSS THE REGION ON SUNDAY NIGHT BRINGING AND END TO THE WARMTH...WITH LOWS IN THE UPPER TEENS TO MID 20S. CONFIDENCE IN MONDAY/MONDAY NIGHT DETAILS RATHER LOW...WITH MODELS SPLIT IN THE DETAILS REGARDING TIMING AND PLACEMENT OF MIDLEVEL THERMAL GRADIENT AND SHORTWAVE TRACKING ACROSS THE CENTRAL PLAINS DURING THAT TIME FRAME. DOES LOOK LIKE THERE WILL BE A PERIOD OF LIGHT SNOW ACROSS THE AREA SOMETIME LATER ON MONDAY AND MONDAY NIGHT...WITH MAYBE AN INCH TO INCH AND HALF OR SO OF ACCUMULATION POSSIBLE AT THIS POINT. WILL BE SOMETHING TO WATCH HOWEVER. WITH COLD AIR ADVECTION MONDAY WILL BE COLDER WITH HIGHS MAINLY IN THE 20S. IN THE EXTENDED...TUESDAY THROUGH FRIDAY...APPEARS TO BE GENERALLY COLD THROUGH THE PERIOD AS A SERIES OF REINFORCING SHORTWAVES TRACK ACROSS THE NORTHERN PLAINS/UPPER MIDWEST IN A NORTHWESTERLY UPPER LEVEL FLOW. CANNOT RULE OUT A COUPLE PERIODS OF LIGHT SNOW DURING THAT TIME FRAME...THOUGH HARD TO PIN DOWN WITH USUAL MODEL DIFFERENCES. TUESDAY AND THURSDAY LOOKING TO BE THE COLDEST DAYS...IN THE TEENS...WARMING TO 20S TO LOWER 30S BY FRIDAY. && .AVIATION.../FOR THE 00Z TAF ISSUANCE/ VFR THROUGH MOST OF THE PERIOD...WITH OCCASIONAL MVFR CEILINGS AND VISBILITIES THROUGH 12Z AS LIGHT SNOW MOVES SOOUTHEAST ACROSS THE REGION. LOWER CLOUDS SHOULD DISSIPATE AFTER 12Z AND NORTHWEST WINDS OF 15 TO 25 MPH WILL DEVELOP FOR SATURDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1111 AM CST THU JAN 12 2012 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...NORTH WINDS IN THE 15 TO 25 KNOT RANGE WITH A FEW HIGHER GUSTS TO 30KTS WILL REMAIN POSSIBLE THROUGH THIS AFTERNOON. HOWEVER THE GENERAL TREND WILL BE GRADUALLY DOWNWARD IN SPEED FOR THE REST OF THE DAY. WINDS WILL STAY STEADY OUT OF THE NORTH THIS EVENING BEFORE LARGELY DROPPING OFF BEFORE MIDNIGHT. SKIES WILL CONTINUE TO CLEAR OUT FROM NORTHWEST TO SOUTHEAST WITH ONLY HIGH CLOUDS REMAINING. VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS. /68-JGG/ && .PREV DISCUSSION... /ISSUED 839 AM CST THU JAN 12 2012/ DISCUSSION...FORECAST IN GENERALLY GOOD SHAPE THIS MORNING AND HAVE MADE LITTLE OVERALL CHANGE. LATEST OBS AND PROFILER DATA COUPLED WITH 12Z RAOB APPEAR TO SHOW A RELATIVE MAXIMUM IN THE LOW LEVEL PRESSURE GRADIENT FROM AROUND PORT ISABEL NORTHWARD TO NEAR VICTORIA TEXAS. LATEST RUC SEEMS TO HANDLE THIS VERY WELL SHOWING A PERIOD OVER THE NEXT COUPLE OF HOURS WHERE OCCASIONAL GUSTS TO AROUND 40 MPH WILL BE POSSIBLE OVER LAND...WITH FREQUENT GALES OVER THE COASTAL WATERS. NAM/RUC CROSS SECTIONS SHOW THE VERTICAL PRESSURE GRADIENT AND RESULTANT DOWNWARD FORCING RELAXING AS THE BOUNDARY LAYER EXPANDS DUE TO SURFACE HEATING THIS MORNING AND AS A RESULT PROGS EASING WINDS AFTER ABOUT 18Z WHICH APPEARS VERY REASONABLE. HAVE ISSUED A SHORT TERM FORECAST TO MENTION THE INCREASED WIND POTENTIAL FOR THE NEXT COUPLE OF HOURS...BUT FALLING BELOW ADVISORY CRITERIA FOR NOW. SEE FIRE WEATHER DISCUSSION BELOW FOR CHANGES TO THE FIRE WEATHER FORECAST PACKAGE. /68-JGG/ FIRE WEATHER...SEEING MORE FREQUENT SUSTAINED WINDS OVER 25 MPH BEGINNING TO COME IN THIS MORNING SLIGHTLY FURTHER WEST THAN ORIGINALLY ANTICIPATED. WITH RH EXPECTED TO WELL EXCEED CRITICAL THRESHOLDS...AND WINDS SHOWING SIGNS OF ALSO DOING SO HAVE EXPANDED THE RED FLAG WARNING TO INCLUDE ALL BUT ZAPATA COUNTY IN OUR CWA UNTIL 4PM THIS AFTERNOON. /68/ PREV DISCUSSION... /ISSUED 545 AM CST THU JAN 12 2012/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...MVFR CONDITIONS WITH BKN020 LOW CLOUDS NEAR THE COAST WITH THE RECENT PASSAGE OF A COLD FRONT. SKC UPSTREAM AND EXPECT SOME CLEARING THIS MORNING BEFORE THICKER LOW CLOUDS DEVELOP TONIGHT. OTHERWISE...BREEZY AND GUSTY NORTH WINDS TODAY... DECREASING TONIGHT. PREV DISCUSSION... /ISSUED 306 AM CST THU JAN 12 2012/ SHORT TERM /TODAY THROUGH FRIDAY/... A COLD FRONT WILL PRETTY MUCH HAVE ARRIVED THROUGH THE CWA AS WE OPEN THE FORECAST TODAY. BEHIND THE FRONT...AN AIR MASS WITH MARITIME POLAR CHARACTERISTICS WILL BE ARRIVING ALONG A LINE THAT STRETCHED NORTHWEST INTO THE PACIFIC NORTHWEST. WE ARE LOOKING FOR BREEZY AND GUSTY NORTH WINDS EARLY ON TODAY...ESPECIALLY IN COASTAL AREAS...WITH BKN LOW CLOUDS ALONG THE COLD FRONT THIS MORNING GIVING WAY TO A TEMPORARY BREAK UP OF CLOUDS THIS AFTERNOON. THEN COLDER AIR WILL EVENTUALLY RESULT IN BKN TO OVC SKIES DEVELOPING BY FRIDAY. NO PRECIP IS FORECAST FOR TODAY...WITH HIGH TEMPERATURES REMAINING LIMITED TO THE 50S. HIGH PRESSURE WILL SETTLE OVERHEAD TONIGHT WITH LIGHT WINDS...AND LOW TEMPERATURES WILL DIP WELL BELOW NORMAL FRIDAY MORNING. MAV GUIDANCE NUMBERS ACROSS THE NORTHERN TIER ARE JUST ABOVE FREEZING...AND WE MAY SEE A FEW SPOTS HIT THE FREEZING MARK OR BELOW FRIDAY MORNING...BUT WITH A RECOGNIZED COLD BIAS...WILL STOP SHORT OF A FREEZE WATCH RIGHT NOW AND JUST GO WITH AN SPS FOR THE NORTHERN COUNTIES TONIGHT. TEMPS FRIDAY WILL RECOVER INTO THE 60S WITH LIGHT NORTHEAST TO EAST WINDS. /54/ LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... SURFACE HIGH PRESSURE WILL FLATTEN AND BEGIN TO SHIFT EAST FRIDAY NIGHT/SATURDAY...AS A SHORTWAVE TROUGH HEADS TOWARD THE TENNESSEE AND OHIO RIVER VALLEYS. WINDS SHOULD BECOME INCREASINGLY EASTERLY AS THIS OCCURS...AND COULD RESULT IN A GRADUAL INCREASE IN GULF MOISTURE OVER THE AREA HEADING INTO THE WEEKEND. WEATHER CONDITIONS HEADING INTO THE WEEKEND SHOULD BE RATHER QUIET /FOR THE MOST PART/. BOUNDARY LAYER MOISTURE /ALTHOUGH INCREASING/ SHOULD REMAIN RATHER LIMITED FOR THE FIRST HALF OF THE WEEKEND...AS A BIT OF SHORTWAVE RIDGING MOVES ACROSS THE REGION. A FEW PERTURBATIONS ARE SHOWN BY THE MODELS IN THE UPPER ATMOSPHERE JUST TO OUR NORTH...BUT THESE ARE LIKELY REFLECTIONS OF THE SUBTROPICAL JET. SO DESPITE AN EXPECTED INCREASE IN CLOUD COVER FOR THE WEEKEND...LITTLE /IF ANY/ RAINFALL IS ANTICIPATED AT LEAST THROUGH SATURDAY. A FLY IN THE OINTMENT REMAINS THE DEVELOPMENT OF A COASTAL TROUGH...WHICH CONTINUES TO BE SHOWN TO VARYING DEGREES BY MOST OF THE MEDIUM-RANGE MODELS EARLY THIS MORNING. AS WINDS BECOME SOUTHEASTERLY ACROSS THE REGION SUNDAY MORNING...LOOK FOR LOW-LEVEL MOISTURE TO DEEPEN AT A RATHER QUICK PACE. IN FACT...PRECIPITABLE WATER VALUES SHOULD RISE ABOVE 1.4 TO 1.5 INCHES FOR MUCH OF SUNDAY. AND WITH THE DEPARTURE OF THE SHORTWAVE RIDGE...SOME OF THE PERTURBED UPPER-LEVEL ENERGY TO OUR NORTH COULD WORK ITS WAY SOUTHWARD. PLENTY OF ISENTROPIC UPGLIDE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 305K THETA SURFACE SHOULD ALSO BE AVAILABLE. DISPENSING WITH THE WEATHER SPEAK...ALL OF THIS WILL LIKELY LEAD TO THE POSSIBILITY OF SOME LIGHT RAIN FOR SUNDAY. RIGHT NOW...I THINK THE GREATEST ODDS OF SEEING RAIN WILL LIKELY OCCUR EASTWARD OF THE MIDDLE VALLEY. AS SUCH...I WILL LIKELY INCREASE THE ODDS OF SEEING RAIN IN THESE REGIONS FOR SUNDAY. JUST A SIDE NOTE -- PROBABILITIES IN THE NUMERICAL GUIDANCE PROBABILITIES HAVE REMAINED IN A NEARLY STEADY-STATE MODE OVER THE PAST 4 OR 5 MODEL CYCLES. WHILE NOT THE ONLY JUSTIFICATION FOR INCREASING RAIN PROBABILITIES...THIS DOES INCREASE MY CONFIDENCE THAT SOMEONE WILL SEE MEASURABLE RAINFALL ACROSS THIS REGION. WHAT APPEARS TO BE OUR BEST OPPORTUNITY TO SEE SOME RAIN THIS WEEKEND WILL BE RATHER SHORT-LIVED...AS MOST OF THE SYNOPTIC SCALE FORCING SHOULD EXIT THE AREA BY MONDAY. WE WILL THEN START WATCHING THE PROGRESSION OF AN UPPER LOW...WHICH SHOULD MOVE ONSHORE THE SOCAL/BAJA CALIFORNIA COAST SUNDAY NIGHT. IT NOW LOOKS LIKE THIS FEATURE SHOULD WEAKEN TO AN OPEN WAVE AS IT HEADS ACROSS THE DESERT SOUTHWEST...AND WILL PROBABLY DO A BIT OF PHASING WITH ANOTHER UPPER-LEVEL SYSTEM MOVING THROUGH THE NORTHERN ROCKIES. THE EASTWARD MOVEMENT OF THIS SYSTEM SHOULD ALLOW A COLD FRONT TO MOVE SOUTHWARD ACROSS MID-AMERICA EARLY IN THE WEEK. IT LOOKS LIKE THE FRONT SHOULD MOVE INTO NORTH TEXAS LATE MONDAY NIGHT/TUESDAY MORNING...THEN ACROSS OUR CORNER OF THE WORLD SOMETIME TUESDAY NIGHT. TIMING OF THIS SYSTEM PRESENTED BY AVAILABLE MEDIUM-RANGE GUIDANCE IS DEBATABLE. MOST MODELS PUSH THE FRONT SOUTH OF THE RIO GRANDE BY WEDNESDAY MORNING. MEANWHILE...GUIDANCE FROM THE HYDROMETEOROLOGICAL PREDICTION CENTER LAGS BEHIND THE OPERATIONAL MODELS SOME 6 TO 12 HOURS. STAY TUNED. FOR NOW...IT DOES NOT LOOK LIKE WE WILL SEE MUCH IN THE WAY OF PRECIPITATION WITH THIS SYSTEM. WITH LOW-LEVEL MOISTURE SOMEWHAT LIMITED...I WILL KEEP RAIN PROBABILITIES AT OR BELOW 14 PERCENT WITH THIS FORECAST PACKAGE. HIGHS WILL LIKELY WARM INTO THE 70S BY THIS WEEKEND...BUT MAY FALL INTO THE 60S BY WEDNESDAY DEPENDING ON THE TIMING OF THE FRONT. LOWS WILL LIKELY GO ABOVE NORMAL IN MOST PLACES GIVEN THE EXPECTED CLOUD COVER DURING MOST PERIODS THROUGH NEXT WEDNESDAY. /53/ MARINE... TODAY THROUGH FRIDAY...A COLD FRONT AND STRONG MARITIME POLAR HIGH PRESSURE WILL SET UP GALE FORCE GUSTS THIS MORNING THROUGH LATE THIS AFTERNOON ON THE GULF...WHILE SMALL CRAFT ADVISORY CONDITIONS WILL EXIST ON THE LAGUNA MADRE. WAVE HEIGHTS WILL LIKELY BUILD TO 12 FEET OFFSHORE. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY CONTINUE ON THE GULF TONIGHT BUT CONDITIONS WILL IMPROVE FRIDAY AS HIGH PRESSURE SPREADS OUT AND SETTLES OVER THE AREA. /54/ FRIDAY NIGHT THROUGH MONDAY...NORTHEAST TO EAST WINDS SHOULD BECOME SOUTHEAST ACROSS THE MARINE AREA BY SUNDAY AS SURFACE HIGH PRESSURE SHIFTS EAST. WINDS AND SEAS SHOULD REMAIN BELOW EXERCISE CAUTION OR ADVISORY CRITERIA THROUGH MOST OF THE WEEKEND. WIND SPEEDS IN WAKE OF A COASTAL TROUGH MAY INCREASE A BIT FOR SUNDAY NIGHT AND MONDAY...AND COULD RESULT IN THE POSTING OF SMALL CRAFT EXERCISE CAUTIONS OR SMALL CRAFT ADVISORIES BY THIS TIME. /53/ FIRE WEATHER... NORTH WINDS AT 20 FEET WILL PEAK AT AROUND NOON TODAY BETWEEN 15 AND 20 MPH WITH GUSTS TO 25 MPH FOR THE INLAND AREAS...BUT THE DRIEST AIR WILL NOT BECOME ESTABLISHED UNTIL MID AFTERNOON...JUST WHEN 20 FOOT WINDS BEGIN DECREASING. THE RELEVANT WEATHER ELEMENTS WILL THUS BE SLIGHTLY OUT OF PHASE. MEETING THE CRITERIA FOR A RED FLAG WARNING WILL BE MARGINAL INLAND...BUT WILL BE JUSTIFIABLE NEAR THE COAST WHERE STRONGER WINDS OF NEAR 25 MPH AT 20 FEET WILL PREVAIL. AS MENTIONED EARLIER...FIRE DANGER CRITERIA WILL BE MET FOR THE REST OF THE CWA INLAND FOR SEVERAL HOURS FROM ABOUT 9 AM TO 3 PM CST TODAY. ZAPATA COUNTY WILL BE MOST MARGINAL FOR THE FIRE DANGER STATEMENT...WITH FORECAST RELATIVE HUMIDITY VALUES BARELY DECREASING TO 25 PERCENT...BUT FELT IT WAS CLOSE ENOUGH TO INCLUDE. /54/ && .BRO WATCHES/WARNINGS/ADVISORIES... TX...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR TXZ249>257. GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS EVENING FOR GMZ130-132-135. SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST FRIDAY FOR GMZ150-155-170-175. GALE WARNING UNTIL 3 PM CST THIS AFTERNOON FOR GMZ150-155-170- 175. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 68/58
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
839 AM CST THU JAN 12 2012 .DISCUSSION...FORECAST IN GENERALLY GOOD SHAPE THIS MORNING AND HAVE MADE LITTLE OVERALL CHANGE. LATEST OBS AND PROFILER DATA COUPLED WITH 12Z RAOB APPEAR TO SHOW A RELATIVE MAXIMUM IN THE LOW LEVEL PRESSURE GRADIENT FROM AROUND PORT ISABEL NORTHWARD TO NEAR VICTORIA TEXAS. LATEST RUC SEEMS TO HANDLE THIS VERY WELL SHOWING A PERIOD OVER THE NEXT COUPLE OF HOURS WHERE OCCASIONAL GUSTS TO AROUND 40 MPH WILL BE POSSIBLE OVER LAND...WITH FREQUENT GALES OVER THE COASTAL WATERS. NAM/RUC CROSS SECTIONS SHOW THE VERTICAL PRESSURE GRADIENT AND RESULTANT DOWNWARD FORCING RELAXING AS THE BOUNDARY LAYER EXPANDS DUE TO SURFACE HEATING THIS MORNING AND AS A RESULT PROGS EASING WINDS AFTER ABOUT 18Z WHICH APPEARS VERY REASONABLE. HAVE ISSUED A SHORT TERM FORECAST TO MENTION THE INCREASED WIND POTENTIAL FOR THE NEXT COUPLE OF HOURS...BUT FALLING BELOW ADVISORY CRITERIA FOR NOW. SEE FIRE WEATHER DISCUSSION BELOW FOR CHANGES TO THE FIRE WEATHER FORECAST PACKAGE. /68-JGG/ && .FIRE WEATHER...SEEING MORE FREQUENT SUSTAINED WINDS OVER 25 MPH BEGINNING TO COME IN THIS MORNING SLIGHTLY FURTHER WEST THAN ORIGINALLY ANTICIPATED. WITH RH EXPECTED TO WELL EXCEED CRITICAL THRESHOLDS...AND WINDS SHOWING SIGNS OF ALSO DOING SO HAVE EXPANDED THE RED FLAG WARNING TO INCLUDE ALL BUT ZAPATA COUNTY IN OUR CWA UNTIL 4PM THIS AFTERNOON. /68/ && .PREV DISCUSSION... /ISSUED 545 AM CST THU JAN 12 2012/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...MVFR CONDITIONS WITH BKN020 LOW CLOUDS NEAR THE COAST WITH THE RECENT PASSAGE OF A COLD FRONT. SKC UPSTREAM AND EXPECT SOME CLEARING THIS MORNING BEFORE THICKER LOW CLOUDS DEVELOP TONIGHT. OTHERWISE...BREEZY AND GUSTY NORTH WINDS TODAY... DECREASING TONIGHT. PREV DISCUSSION... /ISSUED 306 AM CST THU JAN 12 2012/ SHORT TERM /TODAY THROUGH FRIDAY/... A COLD FRONT WILL PRETTY MUCH HAVE ARRIVED THROUGH THE CWA AS WE OPEN THE FORECAST TODAY. BEHIND THE FRONT...AN AIR MASS WITH MARITIME POLAR CHARACTERISTICS WILL BE ARRIVING ALONG A LINE THAT STRETCHED NORTHWEST INTO THE PACIFIC NORTHWEST. WE ARE LOOKING FOR BREEZY AND GUSTY NORTH WINDS EARLY ON TODAY...ESPECIALLY IN COASTAL AREAS...WITH BKN LOW CLOUDS ALONG THE COLD FRONT THIS MORNING GIVING WAY TO A TEMPORARY BREAK UP OF CLOUDS THIS AFTERNOON. THEN COLDER AIR WILL EVENTUALLY RESULT IN BKN TO OVC SKIES DEVELOPING BY FRIDAY. NO PRECIP IS FORECAST FOR TODAY...WITH HIGH TEMPERATURES REMAINING LIMITED TO THE 50S. HIGH PRESSURE WILL SETTLE OVERHEAD TONIGHT WITH LIGHT WINDS...AND LOW TEMPERATURES WILL DIP WELL BELOW NORMAL FRIDAY MORNING. MAV GUIDANCE NUMBERS ACROSS THE NORTHERN TIER ARE JUST ABOVE FREEZING...AND WE MAY SEE A FEW SPOTS HIT THE FREEZING MARK OR BELOW FRIDAY MORNING...BUT WITH A RECOGNIZED COLD BIAS...WILL STOP SHORT OF A FREEZE WATCH RIGHT NOW AND JUST GO WITH AN SPS FOR THE NORTHERN COUNTIES TONIGHT. TEMPS FRIDAY WILL RECOVER INTO THE 60S WITH LIGHT NORTHEAST TO EAST WINDS. /54/ LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... SURFACE HIGH PRESSURE WILL FLATTEN AND BEGIN TO SHIFT EAST FRIDAY NIGHT/SATURDAY...AS A SHORTWAVE TROUGH HEADS TOWARD THE TENNESSEE AND OHIO RIVER VALLEYS. WINDS SHOULD BECOME INCREASINGLY EASTERLY AS THIS OCCURS...AND COULD RESULT IN A GRADUAL INCREASE IN GULF MOISTURE OVER THE AREA HEADING INTO THE WEEKEND. WEATHER CONDITIONS HEADING INTO THE WEEKEND SHOULD BE RATHER QUIET /FOR THE MOST PART/. BOUNDARY LAYER MOISTURE /ALTHOUGH INCREASING/ SHOULD REMAIN RATHER LIMITED FOR THE FIRST HALF OF THE WEEKEND...AS A BIT OF SHORTWAVE RIDGING MOVES ACROSS THE REGION. A FEW PERTURBATIONS ARE SHOWN BY THE MODELS IN THE UPPER ATMOSPHERE JUST TO OUR NORTH...BUT THESE ARE LIKELY REFLECTIONS OF THE SUBTROPICAL JET. SO DESPITE AN EXPECTED INCREASE IN CLOUD COVER FOR THE WEEKEND...LITTLE /IF ANY/ RAINFALL IS ANTICIPATED AT LEAST THROUGH SATURDAY. A FLY IN THE OINTMENT REMAINS THE DEVELOPMENT OF A COASTAL TROUGH...WHICH CONTINUES TO BE SHOWN TO VARYING DEGREES BY MOST OF THE MEDIUM-RANGE MODELS EARLY THIS MORNING. AS WINDS BECOME SOUTHEASTERLY ACROSS THE REGION SUNDAY MORNING...LOOK FOR LOW-LEVEL MOISTURE TO DEEPEN AT A RATHER QUICK PACE. IN FACT...PRECIPITABLE WATER VALUES SHOULD RISE ABOVE 1.4 TO 1.5 INCHES FOR MUCH OF SUNDAY. AND WITH THE DEPARTURE OF THE SHORTWAVE RIDGE...SOME OF THE PERTURBED UPPER-LEVEL ENERGY TO OUR NORTH COULD WORK ITS WAY SOUTHWARD. PLENTY OF ISENTROPIC UPGLIDE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 305K THETA SURFACE SHOULD ALSO BE AVAILABLE. DISPENSING WITH THE WEATHER SPEAK...ALL OF THIS WILL LIKELY LEAD TO THE POSSIBILITY OF SOME LIGHT RAIN FOR SUNDAY. RIGHT NOW...I THINK THE GREATEST ODDS OF SEEING RAIN WILL LIKELY OCCUR EASTWARD OF THE MIDDLE VALLEY. AS SUCH...I WILL LIKELY INCREASE THE ODDS OF SEEING RAIN IN THESE REGIONS FOR SUNDAY. JUST A SIDE NOTE -- PROBABILITIES IN THE NUMERICAL GUIDANCE PROBABILITIES HAVE REMAINED IN A NEARLY STEADY-STATE MODE OVER THE PAST 4 OR 5 MODEL CYCLES. WHILE NOT THE ONLY JUSTIFICATION FOR INCREASING RAIN PROBABILITIES...THIS DOES INCREASE MY CONFIDENCE THAT SOMEONE WILL SEE MEASURABLE RAINFALL ACROSS THIS REGION. WHAT APPEARS TO BE OUR BEST OPPORTUNITY TO SEE SOME RAIN THIS WEEKEND WILL BE RATHER SHORT-LIVED...AS MOST OF THE SYNOPTIC SCALE FORCING SHOULD EXIT THE AREA BY MONDAY. WE WILL THEN START WATCHING THE PROGRESSION OF AN UPPER LOW...WHICH SHOULD MOVE ONSHORE THE SOCAL/BAJA CALIFORNIA COAST SUNDAY NIGHT. IT NOW LOOKS LIKE THIS FEATURE SHOULD WEAKEN TO AN OPEN WAVE AS IT HEADS ACROSS THE DESERT SOUTHWEST...AND WILL PROBABLY DO A BIT OF PHASING WITH ANOTHER UPPER-LEVEL SYSTEM MOVING THROUGH THE NORTHERN ROCKIES. THE EASTWARD MOVEMENT OF THIS SYSTEM SHOULD ALLOW A COLD FRONT TO MOVE SOUTHWARD ACROSS MID-AMERICA EARLY IN THE WEEK. IT LOOKS LIKE THE FRONT SHOULD MOVE INTO NORTH TEXAS LATE MONDAY NIGHT/TUESDAY MORNING...THEN ACROSS OUR CORNER OF THE WORLD SOMETIME TUESDAY NIGHT. TIMING OF THIS SYSTEM PRESENTED BY AVAILABLE MEDIUM-RANGE GUIDANCE IS DEBATABLE. MOST MODELS PUSH THE FRONT SOUTH OF THE RIO GRANDE BY WEDNESDAY MORNING. MEANWHILE...GUIDANCE FROM THE HYDROMETEOROLOGICAL PREDICTION CENTER LAGS BEHIND THE OPERATIONAL MODELS SOME 6 TO 12 HOURS. STAY TUNED. FOR NOW...IT DOES NOT LOOK LIKE WE WILL SEE MUCH IN THE WAY OF PRECIPITATION WITH THIS SYSTEM. WITH LOW-LEVEL MOISTURE SOMEWHAT LIMITED...I WILL KEEP RAIN PROBABILITIES AT OR BELOW 14 PERCENT WITH THIS FORECAST PACKAGE. HIGHS WILL LIKELY WARM INTO THE 70S BY THIS WEEKEND...BUT MAY FALL INTO THE 60S BY WEDNESDAY DEPENDING ON THE TIMING OF THE FRONT. LOWS WILL LIKELY GO ABOVE NORMAL IN MOST PLACES GIVEN THE EXPECTED CLOUD COVER DURING MOST PERIODS THROUGH NEXT WEDNESDAY. /53/ MARINE... TODAY THROUGH FRIDAY...A COLD FRONT AND STRONG MARITIME POLAR HIGH PRESSURE WILL SET UP GALE FORCE GUSTS THIS MORNING THROUGH LATE THIS AFTERNOON ON THE GULF...WHILE SMALL CRAFT ADVISORY CONDITIONS WILL EXIST ON THE LAGUNA MADRE. WAVE HEIGHTS WILL LIKELY BUILD TO 12 FEET OFFSHORE. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY CONTINUE ON THE GULF TONIGHT BUT CONDITIONS WILL IMPROVE FRIDAY AS HIGH PRESSURE SPREADS OUT AND SETTLES OVER THE AREA. /54/ FRIDAY NIGHT THROUGH MONDAY...NORTHEAST TO EAST WINDS SHOULD BECOME SOUTHEAST ACROSS THE MARINE AREA BY SUNDAY AS SURFACE HIGH PRESSURE SHIFTS EAST. WINDS AND SEAS SHOULD REMAIN BELOW EXERCISE CAUTION OR ADVISORY CRITERIA THROUGH MOST OF THE WEEKEND. WIND SPEEDS IN WAKE OF A COASTAL TROUGH MAY INCREASE A BIT FOR SUNDAY NIGHT AND MONDAY...AND COULD RESULT IN THE POSTING OF SMALL CRAFT EXERCISE CAUTIONS OR SMALL CRAFT ADVISORIES BY THIS TIME. /53/ FIRE WEATHER... NORTH WINDS AT 20 FEET WILL PEAK AT AROUND NOON TODAY BETWEEN 15 AND 20 MPH WITH GUSTS TO 25 MPH FOR THE INLAND AREAS...BUT THE DRIEST AIR WILL NOT BECOME ESTABLISHED UNTIL MID AFTERNOON...JUST WHEN 20 FOOT WINDS BEGIN DECREASING. THE RELEVANT WEATHER ELEMENTS WILL THUS BE SLIGHTLY OUT OF PHASE. MEETING THE CRITERIA FOR A RED FLAG WARNING WILL BE MARGINAL INLAND...BUT WILL BE JUSTIFIABLE NEAR THE COAST WHERE STRONGER WINDS OF NEAR 25 MPH AT 20 FEET WILL PREVAIL. AS MENTIONED EARLIER...FIRE DANGER CRITERIA WILL BE MET FOR THE REST OF THE CWA INLAND FOR SEVERAL HOURS FROM ABOUT 9 AM TO 3 PM CST TODAY. ZAPATA COUNTY WILL BE MOST MARGINAL FOR THE FIRE DANGER STATEMENT...WITH FORECAST RELATIVE HUMIDITY VALUES BARELY DECREASING TO 25 PERCENT...BUT FELT IT WAS CLOSE ENOUGH TO INCLUDE. /54/ && .BRO WATCHES/WARNINGS/ADVISORIES... TX...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR TXZ249>257. GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS EVENING FOR GMZ130-132-135. SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST FRIDAY FOR GMZ150-155-170-175. GALE WARNING UNTIL 3 PM CST THIS AFTERNOON FOR GMZ150-155-170- 175. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 68/59/58
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1134 PM CST WED JAN 11 2012 .AVIATION... BREEZY CONDITIONS WILL PERSIST FOR MUCH OF THE OVERNIGHT AT KCDS WITH A RETURN TO WINDY CONDITIONS DURING THE AFTERNOON. WINDS MAY BECOME BREEZY AT KLBB DURING THE AFTERNOON BUT WILL GO LIGHT BY EARLY IN THE EVENING. && PREV DISCUSSION... /ISSUED 352 PM CST WED JAN 11 2012/ SHORT TERM... THE SURFACE PRESSURE GRADIENT SUPPORTING TODAYS STIFF NORTHERLY WINDS IS EXPECTED TO EASE STEADILY THIS EVENING...WITH DROP IN MOST SURFACE WIND SPEEDS NEAR OR PRIOR TO 00Z THIS EVENING. OUR PLAN IS TO ALLOW THE WIND ADVISORY TO RUN ITS COURSE UNTIL 00Z WITH NO EXTENSION. WINDS PROBABLY WILL BE SLOWEST TO DROP THIS EVENING OVER THE ROLLING PLAINS AND MAY RETAIN GREATER THAN 10 MPH WINDS UNTIL CLOSE TO DAYBREAK ON THURSDAY. THIS SHOULD KEEP ESPECIALLY THE SOUTHERN ROLLING PLAINS BETTER MIXED WHILE LOW TEMPERATURES OTHERWISE TONIGHT SHOULD DROP INTO TEENS ON MOST OF THE CAPROCK AND LOW TO MID 20S OVER ROLLING PLAINS. THE UPPER FLOW SHOULD REMAIN SLIGHTLY ANTICYCLONICALLY CURVED IN NORTHWEST FLOW ALOFT WITH A BRANCH OF THE POLAR JET STILL OVER THE AREA UNTIL MIDDAY THURSDAY. THIS MAY LEAD TO AREAS OF MID CLOUDS AGAIN LATER TONIGHT AND/OR THROUGH THURSDAY...THOUGH SOMEWHAT DIFFICULT TO ANTICIPATE. LOW CLOUDS TONIGHT ALSO SOMEWHAT UNCERTAIN GIVEN PREDOMINANT NORTHERLY LOW LEVEL FLOW AND VERY DRY AIR...THOUGH RUC INDICATES ABOUT 20 DEGREES MORE NORTHEAST COMPONENT AND MAINTAINS MORE H850 LAYER MOISTURE ACROSS NORTHERN AND EASTERN ZONES. SO...APPEARS PERHAPS BEST AREAS FOR MVFR LAYER LOW CLOUDS WOULD BE ACROSS NORTHEAST ZONES BUT CANT RULE OUT FOR CENTRAL. EITHER WAY...A CHILLY NIGHT WILL OCCUR WITH A FLATTER SURFACE PRESSURE GRADIENT DOMINATING THROUGH MUCH OF THURSDAY. TRENDED HIGHS THURSDAY VERY SLIGHTLY UPWARDS ALONG LINES OF GUIDANCE TRENDS AS WELL. RMCQUEEN LONG TERM... EXPECT DRY CONDITIONS AND MODERATING TEMPERATURES LATE WEEK ON THROUGH THE WEEKEND. INITIALLY...A SHORTWAVE TROUGH EMBEDDED WITHIN NORTHWESTERLY FLOW ALOFT WILL TRAVERSE THE AREA FRIDAY. THIS DISTURBANCE WILL GENERATE AREAS OF MID/HIGH CLOUD BUT LITTLE ELSE. THE NORTHWESTERLY FLOW WILL BACK WITH TIME WITH A PROGRESSIVE UPPER RIDGE TRANSLATING OVER SATURDAY NIGHT AND SUNDAY. THIS PATTERN...COMBINED WITH INCREASING SOUTHERLY/SOUTHWESTERLY LOW- LEVEL FLOW...WILL PUSH HIGHS BACK ABOVE AVERAGE OVER THE WEEKEND /LIKELY ECLIPSING THE 60 DEGREE MARK BY SUNDAY/. ONE MINOR CAVEAT REVOLVE AROUND A CLIPPER SYSTEM DIVING INTO THE UPPER MIDWEST THAT MAY ATTEMPT TO BACKDOOR A WEAK COLD FRONT INTO THE NORTHEAST ZONES ON SATURDAY. EVEN IF THIS FRONT DOES MAKE IT INTO THE AREA...ONLY MINOR IMPACTS ARE EXPECTED. THUS...HAVE TRENDED FORECAST TEMPERATURES UP A NOTCH OVER THE WEEKEND. ATTENTION WILL THEN TURN TO ANOTHER SHORTWAVE TROUGH /THE REMNANTS OF THE CUTOFF LOW CURRENTLY SPINNING WELL OFF THE CALIFORNIA COAST/ THAT WILL RACE BY THE REGION IN NEAR ZONAL FLOW ALOFT ON MONDAY. UNFORTUNATELY THE PROGRESSIVE AND OPENING/WEAKENING NATURE OF THE SYSTEM...ALONG WITH THE DEARTH OF LOW-LEVEL MOISTURE TO WORK WITH...WILL LIKELY KEEP THIS SYSTEM A DRY ONE LOCALLY. HOWEVER...IF YOU LIKE WIND YOU MAY BE IN STORE FOR ANOTHER TREAT AS THE LATEST GUIDANCE AND RAW NWP MODEL OUTPUT SUGGEST WESTERLY WINDS MAY APPROACH OR EXCEED ADVISORY LEVELS DURING THE DAY MONDAY. HENCE...HAVE TRENDED WINDS SPEEDS UPWARD IN THE GRIDS...THOUGH A TOUCH BELOW ADVISORY LEVELS AT THIS POINT. THESE WINDS COULD ALSO LOFT A BIT OF BLOWING DUST /LIKE TODAY/ AND ALSO ELEVATE THE FIRE DANGER. HOWEVER...CURRENT PROJECTIONS DO KEEP HUMIDITIES ABOVE MORE CRITICAL THRESHOLDS...THOUGH THIS COULD BE A BIT OPTIMISTIC AS IS OFTEN THE CASE IN THE STRONG WESTERLY FLOW REGIME. BEYOND MONDAY...A COLD FRONT IS PROGGED TO MOVE THROUGH EARLY TUESDAY...DROPPING TEMPERATURES TOWARD MORE SEASONAL LEVELS. THE LATEST ROUND OF MODEL SOLUTIONS HAVE TRENDED A LITTLE STRONGER WITH THE FRONT...PUSHING IT THROUGH THE ENTIRE FA...AND HAVE FOLLOWED SUITE IN THE GRIDS. THIS COOL-DOWN SHOULD BE RELATIVELY SHORT-LIVED THOUGH AS THE SFC RIDGE IS QUICKLY SHUNTED EASTWARD UNDER MODERATE TO STRONG MID-LEVEL ZONAL FLOW IN PLACE ACROSS MUCH OF THE CONUS. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 16 41 18 47 23 / 10 0 0 0 0 TULIA 17 42 17 49 22 / 10 0 0 0 0 PLAINVIEW 18 42 19 50 23 / 10 0 0 0 0 LEVELLAND 19 43 21 51 25 / 10 0 0 0 0 LUBBOCK 19 43 21 51 23 / 10 0 0 0 0 DENVER CITY 21 42 23 49 26 / 0 0 0 0 0 BROWNFIELD 22 43 23 50 25 / 0 0 0 0 0 CHILDRESS 23 45 20 53 24 / 10 0 0 0 0 SPUR 24 46 23 53 26 / 10 0 0 0 0 ASPERMONT 25 46 25 54 25 / 10 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1114 AM CST THU JAN 12 2012 .UPDATE... SNOW FINALLY SPREAD INTO MILWAUKEE AT 1015 THIS MORNING...BUT IT WAS NOT FROM THE SYSTEM SNOW SPREADING EASTWARD. IT WAS FROM A SNOW BAND SITTING OVER THE LAKE THAT PIVOTED WESTWARD INTO MILWAUKEE. IT IS STILL NOT SNOWING IN KENOSHA. WITH THE LOW LEVELS ALREADY SATURATED DUE TO THE COLD AIR ADVECTION...AND THE UPPER LEVELS SATURATED AS WELL...THE MID LEVELS NEAR THE LAKE ARE VERY SLOWLY BECOMING SATURATED. ANY DRIZZLE OR DRY WEATHER WILL BECOME SNOW AT KENOSHA AIRPORT WITHIN THE NEXT HALF HOUR. FRONTOGENETIC BANDS ARE EXPECTED TO DEVELOP RAPIDLY EARLY THIS AFTERNOON ACROSS NORTHERN IL. AT THIS TIME...MODELS SHOW THIS AREA REMAINING JUST SOUTH OF THE WI/IL BORDER...STALLING IN AN EAST-WEST ORIENTATION. BUT THERE IS A POSSIBILITY THAT THEY COULD DRIFT INTO SOUTHERN WI AS THE SYSTEM PIVOTS AROUND THE UPPER LOW. THE OTHER CONCERN WILL BE WATCHING FOR LAKE EFFECT/ENHANCEMENT NEAR THE LAKESHORE COUNTIES. THE RUC IS SHOWING A PERIOD OF NNE 1000-900MB WINDS AND CONVERGENCE ALONG THE LAKESHORE BETWEEN 18Z TO 21Z FROM SHEBOYGAN SOUTH THROUGH NORTHEAST IL...THOUGH THE STRONGEST CONVERGENCE REMAINS JUST OFFSHORE. THE RUC SHOWS A FOCUSED MAX CONVERGENCE OVER FAR SOUTHEAST WI AROUND 00Z THAT DROPS SOUTH OUT OF THE STATE BY 03Z. THE HRRR KEEPS THE CONVERGENCE AND HIGHER PRECIP AMOUNTS OFFSHORE WITH A MORE NNW WIND FLOW. WILL NEED TO KEEP MONITORING THE SHORT-TERM MODELS FOR HEADLINE CONCERNS AND KEEP STRESSING THE POOR WEATHER DURING THE AFTERNOON COMMUTE. && .AVIATION/18Z TAFS/... EXPECT IFR/LIFR LEVELS ACROSS THE AREA THROUGH THE AFTERNOON. CONDITIONS SHOULD BEGIN TO LIFT TO MVFR LEVELS LATER THIS EVENING AND OVERNIGHT AS THE SNOW BEGINS TO WIND DOWN. BY 6 PM THE KMSN AREA SHOULD HAVE AROUND 3.5 TO 4 INCHES ON THE GROUND WITH THE PEAK OF THE SNOW OCCURRING AROUND 18-20Z. ANOTHER INCH SHOULD OCCUR AFTER 00Z FRIDAY. AT KMKE...ABOUT 3 INCHES SHOULD BE REALIZED BY 00Z THIS EVENING WITH ANOTHER 2 INCHES BEFORE MIDNIGHT. THE PEAK OF THE SNOW IN MILWAUKEE WILL CLOSER TO 23-01Z. LOOK FOR NORTHWEST WINDS OF 15 TO 25 MPH WITH A FEW GUSTS TO 30 MPH THROUGH THE EVENT. LAKE ENHANCED SNOW MAY CAUSE SLIGHTLY HIGHER SNOWFALL RATES AT TIMES AT MKE AND ENW. A BAND OF SNOW EXPECTED TO LINE UP EAST TO WEST ACROSS FAR NORTHERN IL HAS THE POSSIBILITY OF DRIFTING NORTHWARD INTO WALWORTH AND KENOSHA COUNTIES THIS AFTERNOON AND NEEDS TO BE MONITORED. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 4 AM CST FRIDAY FOR WIZ046-047-056- 057-062-063-067>069. WINTER WEATHER ADVISORY UNTIL 9 AM CST FRIDAY FOR WIZ051-052- 058>060-064>066-070>072. LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST FRIDAY NIGHT FOR LMZ643>646. && $$ UPDATE...MRC
AREA FORECAST DISCUSSION
NWS ALBANY NY
1239 AM EST SAT JAN 14 2012 .SYNOPSIS... LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES INTO THE CANADIAN MARITIMES OVERNIGHT. BLUSTERY AND COLD CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1235 AM EST...SNOW SHOWERS/FLURRIES HAVE INCREASED IN AREAL COVERAGE ONCE AGAIN FROM THE CAPITAL REGION WEST AND NORTH...WITH A BAND OF HEAVIER SNOW SHOWERS EVIDENT ON RADAR ACROSS SOUTH CENTRAL HERKIMER CO INTO NORTHERN SARATOGA CO. THIS BAND HAS BEEN MOVING SLOWLY SOUTHWARD...AND AS LOW LEVEL WINDS CONTINUE VEERING...THIS BAND SHOULD ALSO CONTINUE MOVING SOUTH...AFFECTING THE WESTERN MOHAWK VALLEY OVER THE NEXT 1-2 HOURS...AS WELL AS AREAS FROM THE CAPITAL REGION N AND W. WITHIN THIS BAND...LOCALLY HEAVY BURSTS OF SNOW WILL BE POSSIBLE. EXPECT AN ADDITIONAL 1-3 INCHES ACROSS PORTIONS OF SOUTHERN HERKIMER CO...WITH GENERALLY A DUSTING TO UNDER AN INCH ELSEWHERE. HAVE INCREASED POPS FOR THESE AREAS ACCORDINGLY BASED ON RADAR TRENDS. ELSEWHERE...SNOW SHOWERS ARE PERSISTING ACROSS NORTHERN HERKIMER/HAMILTON COS. ALTHOUGH INTENSITY HAS DECREASED...STILL CAN EXPECT UP TO AN ADDITIONAL INCH OR TWO OF ACCUM THROUGH DAYBREAK. WILL KEEP CURRENT SUITE OF ADVISORIES FOR THIS REGION. HAVE BOOSTED TEMPS UPWARD...AND SLOWED THE TEMP CURVE OVER THE NEXT 3 HOURS...AS PERSISTENT CLOUDS...AND SOME LOW LEVEL WARMTH/MOISTURE FROM THE LAKES KEEP TEMPS FROM FALLING MUCH...GENERALLY HOLDING IN THE 25-30 RANGE. THEN...TOWARD DAYBREAK...A QUICKER DROP OFF IN TEMPS IS EXPECTED AS THE ARCTIC COLD FRONT DRIFTS SE. ACTUAL MIN TEMPS MAY NOT OCCUR UNTIL AROUND OR JUST AFTER DAYBREAK. PREVIOUS DISCUSSIONS FOLLOW... WINTER STORM WARNING AND SOME OF THE WINTER WEATHER ADVISORIES HAVE BEEN DROPPED. SNOW HAS DIMINISHED GREATLY ACROSS THE REGION AS THE INVERSIONS AND MOISTURE LAYER HAVE BECOME MORE SHALLOW. LAKE EFFECT BAND NOSING INTO HERKIMER AND HAMILTON COUNTIES RELATIVELY STABLE AND SHOULD CONTINUE TO PRODUCE LIGHT TO MODERATE SNOW...LOCALLY HEAVY SNOW THROUGH THE EARLY MORNING HOURS. HAVE DROPPED ALL HEADLINES EXCEPT FOR THE WINTER WEATHER ADVISORY IN THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...WHERE IT HAS BEEN EXTENDED UNTIL 6 AM. THE LAKE EFFCT BAND MAY BREAK UP BEFORE THEN BUT IT CAN BE CANCELLED EARLY IF NECESSARY. THERE MAY BE ONLY AN INCH OR TWO ADDITIONAL ACCUMULATION IN THOSE AREAS...WITH STORM TOTALS OF 4 TO UP TO AROUND 8 INCHES LOCALLY. WITH THE CLOUD COVER AND THE WINDS STAYING UP...TEMPERATURES ARE NOT FALLING MUCH...BUT UPSTREAM TEMPERATURES SHOULD ADVECT INTO OUR REGION BY DAYBREAK. SO...LOW TEMPERATURES SEEM TO BE IN THE BALLPARK. PREV AFD BELOW... WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED. SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS. SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE CHANGES LATER THIS EVENING. PREV AFD BELOW... AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA COUNTIES TO 4-8" TOO. PREVIOUS NEAR TERM... AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES. THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK VALLEY. THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z- 03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS. THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE. LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE WILL HAVE TO MONITOR IF THIS MATERIALIZES. IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35 KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO 35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS AROUND 35 MPH. A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH. LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN MTNS. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST. THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO NORTH AND WEST OF THE CAPITAL REGION. SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN THE SRN DACKS. SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS NORTH. && .LONG TERM /MONDAY THROUGH FRIDAY/... A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY. THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A WINTRY MIX...DEPENDING ON ELEVATION. THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS. NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... MONITORING A BAND OF LAKE EFFECT SNOW THAT CONTINUES TO MIGRATE SOUTH ACROSS THE MOHAWK VALLEY. LATEST RUC13/HRRR DOES SUGGEST THIS BAND WILL HAVE AN IMPACT ON KALB AND WE WILL PLACE A TEMPO GROUP FOR MVFR CONDITIONS UP TO 09Z. OTHERWISE...HIGH END MVFR OR VFR CONDITIONS ARE EXPECTED THIS TAF FORECAST CYCLE. WINDS WILL REMAIN ELEVATED THANKS TO A TIGHT PRESSURE GRADIENT AND INCREASING MIXING POTENTIAL WITH SUNRISE. WIND GUSTS COULD EXCEED 20KTS WITH A GENERAL WEST-NORTHWEST WIND DIRECTION. WINDS WILL BECOME NORTHWEST IN THE WAKE OF THE LAST FRONTAL BOUNDARY FROM THIS AFTERNOON INTO SATURDAY EVENING. OUTLOOK... SAT OVRNT-MON...VFR...NO SIG WX. MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX. WED...VFR...SLGT CHC --SHSN. && .HYDROLOGY... NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL BY TUESDAY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NYZ032-033-038. MA...NONE. VT...NONE. && $$ SYNOPSIS...KL/NAS/WASULA NEAR TERM...KL/NAS/WASULA SHORT TERM...WASULA LONG TERM...KGM/LFM AVIATION...BGM HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
356 AM EST SAT JAN 14 2012 .SYNOPSIS... A COLD FRONT EXTENDED FROM NORTHERN NEW ENGLAND TO THE GREAT LAKES EARLY THIS MORNING. THE BOUNDARY WILL PROGRESS TO THE SOUTH AND IT SHOULD DROP INTO OUR REGION TONIGHT. COLD HIGH PRESSURE FROM THE WEST IS EXPECTED TO INFLUENCE OUR WEATHER FOR SUNDAY AND SUNDAY NIGHT BEFORE PASSING OUT TO SEA ON MONDAY. A WARM FRONT FROM THE WEST AND SOUTHWEST IS ANTICIPATED TO WORK ITS WAY THROUGH OUR REGION ON TUESDAY, FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT. AN AREA OF HIGH PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY NIGHT OR FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A 07Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO THE NORTHERN OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST. A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY. THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW- LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND. THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. FOR NOW, LEANED TOWARD THE NAM/WRF FOR POPS WHICH PLACES SLIGHT CHC TO CHC RANGE VALUES MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE- HALF INCH OF SNOW ACCUMULATION ACROSS THE POCONOS. ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS. SPEAKING OF STRATOCUMULUS, THESE WILL BE AROUND TODAY ESPECIALLY ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY AS THE WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN INVERSION. THE FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER CLOSE TO THE CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER LEVELS BEING RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME STRATOCUMULUS BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA, WHICH MAY RESULT IN VARYING CLOUD COVER THROUGH THE DAY. A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED BLEND OF THE MOS GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH AND EAST OF THE PHILADELPHIA METRO AREA. AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE AREA. AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER LOCALES. && .LONG TERM /SUNDAY THROUGH FRIDAY/... MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS. THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID LEVEL CLOUDS. ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT WILL SUPPORT ALL RAIN ON MONDAY NIGHT. AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES. ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE FORECASTING. A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT NORMAL FOR THIS TIME OF THE YEAR. A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW- LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE TAFS AT THIS TIME. THE COLD WESTERLY FLOW COMBINED WITH ENOUGH MOISTURE TRAPPED UNDER AN INVERSION IS HELPING TO PULL STRATOCUMULUS DOWN INTO PARTS OF THE AREA. THIS IS EXPECTED TO CONTINUE WITH AT LEAST BROKEN CEILINGS AROUND 4,000 FEET, MAINLY FROM THE KPHL METRO ON NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME WITH GUSTS DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS MORNING. ALL OF OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN THE 20-25 KNOT RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER IN THE AFTERNOON AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD MAINTAIN SOME STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT AS IT DROPS SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO TURN THE SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT. OUTLOOK... DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG, KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE, KILG, KMIV AND KACY. A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER SHOULD FOLLOW FOR WEDNESDAY. && .MARINE... AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW. A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED TONIGHT AS HIGH PRESSURE EDGES CLOSER. WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL CONDITIONS. WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET. A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER, GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430- 431-450>455. && $$ SYNOPSIS...IOVINO NEAR TERM...GORSE SHORT TERM...GORSE LONG TERM...IOVINO AVIATION...GORSE/IOVINO MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
335 AM EST Sat Jan 14 2012 .SYNOPSIS... 08Z water vapor and H4 RUC analysis shows an upper level pattern consisting of longwave troughing over much of the inter-mountain west, followed downstream by longwave troughing over much of the CONUS east of the continental divide. A series of shortwaves beginning to arrive along the British Columbia coastline will slowly break down the western U.S. ridge during the upcoming weekend which will lead to eventual height rises and an overall warmup for the eastern states by the early portion of next week. For now however, watching a shortwave impulse rounding the base of the main eastern trough over the SE states early this morning. The trough axis is just now exiting east of our area, seen with an expanding area of subsidence/drying overhead on WV imagery. A final piece of energy is sliding down the backside of the trough through the mid-section of the country. This energy will slide to our north tonight allowing height rises in its wake for Sunday. At the surface, 1028mb high pressure centered along the TX/LA coasts continues to build east into our forecast area. As the ridge expands eastward, the local gradient has been slowly weakening allowing for an increasingly efficient radiational cooling setup. Still anticipate a widespread light freeze by sunrise away from the immediate coast. A few isolated and normally colder locations may still briefly reach hard freeze criteria in the hour or two surrounding sunrise. && .SHORT TERM (TODAY THROUGH MONDAY)... Today, Subsidence behind the departing shortwave this morning will help promote mostly sunny skies through the day. However, a slight re-enforcing shot of CAA...especially above the surface will keep temperatures a bit below normal. At the surface, high pressure will continue to expand eastward with a high center forming over the coastal waters by the later afternoon/evening hours. To our north, a weak surface reflection/low associated with the final shortwave impulse will translate quickly from MO this afternoon, to the TN valley this evening. Associated with this feature will be a weak cold front that will cross northern AL/GA and into the Carolinas. Although this cold front will not directly pass through our area, it will have an influence of somewhat tightening the gradient over our northern zones later today/this evening. The tighter gradient may have an impact on temperatures tonight. Before that, afternoon temps today are expected to top out in the mid/upper 50s. Tonight, As mentioned above, some uncertainly with regards to temperatures relating to how rapidly the gradient will collapse again over our northern/NE zones in the wake of a passing cold front/trough. The impact looks to be least along and south of the I-10 corridor where proximity to the eastward extension of the surface ridge should set up good radiational cooling conditions early. The temperatures drop may be slower this evening further to the north, however the GFS/ECMWF both show a quick exit of the trough and the potential for late night de-coupling. Therefore, will not deviate far from a MET/MAV blend for overnight lows. Generally looking for lows in the low/mid 30s inland and mid/upper 30s at the coast. Does appear that any location which do reach or drop just below freezing will not do so until right around sunrise, with a fairly short duration of near freezing temps. If the tighter gradient holds longer than numerical guidance currently suggest, then low temps would not be quite as cold for areas north of KTLH and KVLD. Sunday/Sunday night, Very pleasant day upcoming for the second half of the weekend. Rising heights over-top a strong surface ridge will provide the region with dry and seasonable conditions. Winds will be on the light side, which will slow the overall diurnal mixing, however should still be able to reach afternoon highs very close to climatology in the 59-64 range. Sunday night the surface ridge will exit to our east allowing a slow increase in gradient and also low level moisture. Current guidance still suggest a cool overnight with lows in the mid 30s inland to the low 40s at the coast. Monday, Stacked ridging will allow temperatures to finally rise above normal for most locations. Still not anticipating all that efficient a mixing environment, and therefore will likely not realize the full potential of the column that 850mb temps around 10C would suggest. However, not too many will be complaining as temps rise into the upper 60s to near 70 under partly sunny skies. The SE/S flow is likely to keep immediate coastal areas a bit cooler, especially along the Apalachee Bay coastline where shelf water temps are in the upper 50s. && .LONG TERM (TUESDAY THROUGH NEXT SATURDAY)... The large scale longwave pattern commences fairly amplified. This is highlighted in the Nrn stream by troughing across Plains and weak ridging in between. Srn stream with weak troughing Desert SW and weak ridging elsewhere. At surface, high along Carolina coast ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front Swwd across Wrn TN Valley and into TX. During the rest of the period, Plains upper trough digs rapidly SEWD accompanied by shortwave and merges with Desert SW Trough crossing the Nrn Gulf Tues into Tues night. In response, Srn stream upper ridge shunted offshore. At surface, this trough pushes surface low to Srn Great Lakes kicking high further into Atlc. Assocd cold front with limited instability dragged rapidly Sewd with deep sly flow setup from Gulf. GFS and ECMWF similar in timing and intensity of front, and about six hours slower than 24 hrs ago, pushing thru Wrn CWA Tues night exiting Ern most zones Wed morning bringing sct shwrs and possibly a few tstms. Trough pushes into Atlc beginning Wed night. In its wake, NWLY steering flow once again dominates local area as strong high builds SEWD from Srn Plains spreading a reinforcing shot of cold and very dry offshore air across local region Wed into late Thurs. However coldest air remains well to our north so not expecting a solid freeze event. By early Fri, models consistent with next albeit weak shortwave that helps developing surface low which moves moves newd into Lwr MS Valley dragging trailing cold front to Wrn Gulf. Locally, this pushes the dry airmass EWD and high offshore increasing onshore flow and clouds beginning Fri night. Forecast will show low-mid sct pops Tues aftn especially NW third expanding everywhere on Wed morning down to wdly sct-low sct Wed aftn. Otherwise nil pops thru period. Ahead of the front min temps will be around 10 degrees above climo Mon and Tues nights dropping to at or below climo Wed night and may reach freezing in coldest locales then inching to slightly above climo on Thu night. Max temps commence at least 10 degrees above climo on Tues dropping to at or slightly above climo on Wed then inching up to a few degrees each day thru Fri. Average inland min/max temps are 39/62. && .MARINE... High pressure will build over the coastal waters today allowing winds and seas to subside. A brief surge of westerly winds may approach cautionary levels overnight into early Sunday morning before quickly diminishing by the afternoon. The ridge of high pressure will then move east of our region Sunday night allowing winds to come around to the east and southeast and increase to moderate levels for the early portion of next week. A weak cold front is schedule to cross the northeast Gulf Tuesday night or Wednesday with a shift back to offshore flow in its wake. && .AVIATION (through 06Z Sunday)... VFR Conditions with mainly clear skies through the period. Calm winds increase to west to northwest around 5 mph after sunrise, then calm again after sunset. && .FIRE WEATHER... Expect a faster warmup and higher afternoon temperatures today compared to yesterday. Therefore with a persistent dry airmass expect around 4 hour durations of RH below 25% in our Alabama and Georgia zones, altho ern counties of GA iffy. But...with warning already in effect will elect to keep it everywhere and have day shift reevaluate. For our Florida zones, altho critical humidities will be realized, latest dispersions as well as ERC and 20 foot winds should remain under critical levels. Therefore inherited watch has been discontinued. Airmass should moisten slightly on Sunday precluding red flag conditions over AL/GA. Once again low humidities in FL will be offset by ERC...dispersion and winds below critical levels. Red flag conditions are not anticipated during the upcoming work week. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 57 32 62 33 68 / 0 0 0 0 0 Panama City 57 40 62 43 61 / 0 0 0 0 0 Dothan 59 35 59 36 69 / 0 0 0 0 0 Albany 57 32 59 34 70 / 0 0 0 0 0 Valdosta 56 33 60 35 68 / 0 0 0 0 0 Cross City 58 31 64 34 70 / 0 0 0 0 0 Apalachicola 56 36 61 41 60 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for Coffee-Dale-Geneva-Henry-Houston. GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay- Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier- Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole- Terrell-Thomas-Tift-Turner-Worth. FL...None. GM...None. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
236 AM CST SAT JAN 14 2012 .DISCUSSION... ISSUED 235 AM CST SAT JAN 14 2012 LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY. HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN SHEARING OUT OVER THE CENTRAL PLAINS. PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY. SHORT TERM...TODAY THROUGH TUESDAY... SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH. SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY. LONG TERM...WEDNESDAY THROUGH FRIDAY... FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN THE PERIOD. GEELHART && .AVIATION... ISSUED 1116 PM CST FRI JAN 13 2012 LOW CLOUDS/FLURRIES HAVE CLEARED THE TAF SITES EXPECT FOR BMI AND CMI...AND THESE SITES SHOULD CLEAR OUT IN THE NEXT HOUR OR SO. OUT WEST...THE NEXT CLIPPER IS ALREADY SPREADING CLOUDS AND SOME RADAR RETURNS ACROSS THE WESTERN HALF OF IA AND NORTHWESTERN MO. THE SURFACE REFLECTION NOW OVER EASTERN NEB WILL MOVE ALONG THE LOW LEVEL BAROCLINIC ZONE FROM MORTHWEST TO SOUTHEAST ACROSS MO THEN TO MIDDLE TN BY 00Z SUN. ALTHOUGH THE SHORT RANGE MODELS MOSTLY KEEP THE LIGHT SNOW WITH THIS SYSTEM TO THE SOUTHWEST OF SPI...IT WILL BE A CLOSE ENOUGH SHAVE TO CONTINUE WITH VCSH THERE AROUND 12Z-18Z. WILL KEEP OTHER TERMINALS DRY WITH JUST SOME SCATTERED STRATOCU AND BROKEN MID/HIGH CLOUDS. AN UPPER SHEAR AXIS EXTENDS BACK FROM THE NEB CLIPPER TO NORTHERN ND...WHICH WILL TAKE A MORE NORTHERLY TRACK ACROSS THE LOWER GREAT LAKES WITH LITTLE SURFACE REFLECTION. MID LEVEL LIFT/FRONTOGENESIS IS FORECAST TO BRUSH NORTHERN IL AFTER 00Z SUN...BUT MOST OF THE PRECIPITATION SHOULD BE TO THE NORTH OF PIA/BMI. SURFACE WINDS THIS PERIOD WILL BE QUITE VARIABLE...BUT LESS THAN 10 KT MOST OF THE TIME AS THE SURFACE LOW MOVES SOUTH OF THE AREA AND A WEAK PRESSURE GRADIENT PREVAILS TO THE NORTH. 04 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1106 PM CST FRI JAN 13 2012 .AVIATION... THE SMALL LOW PRESSURE SYSTEM THAT WAS EXPECTED TO BRING LIGHT SNOW AND MVFR CIGS TO THE AREA TOMORROW NO LONGER SEEMS TO BE A THREAT AS IT PASSES MAINLY OVER WESTERN IOWA. THE ONLY REAL THREAT FOR THESE CONDITIONS NOW SEEMS TO BE TOWARDS 00Z IN NORTHEAST IOWA...BUT THAT THREAT SEEMS VERY LOW RIGHT NOW. THUS LIGHT WINDS AND VFR WEATHER SHOULD PERSIST AT ALL SITES THROUGH 06Z/15. ALL CIGS TODAY SHOULD BE 5000 TO 8000 FT. && .PREV DISCUSSION... /ISSUED 327 PM CST FRI JAN 13 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS AN EXTRATROPICAL CYCLONE IN SOUTHEAST CANADA WITH NUMEROUS TROFS FROM THE TENNESSEE VALLEY BACK INTO THE UPPER MIDWEST. RADAR TRENDS THROUGH MID AFTERNOON CONTINUE TO SHOW PLENTY OF FLURRIES AND LIGHT SNOW OVER THE MID MISSISSIPPI VALLEY. CLEARING UNDER THE CYCLONIC FLOW WAS MAKING SLOW BUT STEADY PROGRESS EASTWARD. 18Z SFC ANALYSIS HAS A COLD FRONT FROM THE EASTERN GREAT LAKES BACK INTO NORTHEAST ILLINOIS WITH A HIGH PRESSURE RIDGE FROM MINNESOTA INTO EASTERN TEXAS. A CHINOOK WARM FRONT WAS OVER THE EASTERN PARTS OF THE DAKOTAS AND NEBRASKA. A WARM FRONT ASSOCIATED WITH THE NEXT CLIPPER SYSTEM WAS MOVING OUT OF THE NORTHERN ROCKIES. DEW POINTS UNDER THE HIGH PRESSURE RIDGE WERE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. OTHERWISE DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE MIDWEST AND PLAINS. SHORT TERM...TONIGHT AND SATURDAY... LIGHT SNOW WILL CONTINUE THROUGH LATE AFTERNOON BUT WILL TAPER TO FLURRIES ONCE SUNSET OCCURS. RUC TRENDS CONTINUE TO SHOW WEAK F VECTOR CONVERGENCE AND WEAK FRONTOGENETICAL FORCING WILL REMAIN ACROSS THE AREA INTO THE EARLY EVENING. THAT COMBINED WITH THE SHALLOW ARCTIC AIR MASS AND A VORT MAX MOVING THROUGH THE CWFA WILL ALLOW FLURRIES TO PERSIST THROUGH MID EVENING. CLEARING WILL OCCUR FROM WEST TO EAST DURING THE EVENING AND OVERNIGHT HOURS. TEMPERATURES SHOULD DROP QUICKLY ONCE CLEARING OCCURS DUE TO THE SNOW COVER AND LIGHT WINDS. AFTER MIDNIGHT...WAA CLOUDS FROM THE APPROACHING CLIPPER SYSTEM WILL MOVE INTO THE AREA AND LIKELY ALLOW TEMPERATURES TO BOTTOM OUT AND SLOWLY RISE. AFTER 3 AM...ALL MODELS SHOW F VECTOR CONVERGENCE DEVELOPING AGAIN WITH COLLAPSING CONDENSATION PRESSURE DEFICITS ALONG WITH AN INCREASE IN FRONTOGENETICAL FORCING. MOISTURE WITH THIS CLIPPER SYSTEM IS LIMITED BUT FLURRIES AND LIGHT SNOW SHOULD BREAK OUT PRIOR TO DAWN GENERALLY WEST OF A KIIB TO KPPQ LINE. SCHC/CHC POPS WERE DONE DUE TO THE LIMITED MOISTURE BUT MAY NEED TO BE RAISED IN THE EXTREME WEST AND SOUTHWEST PARTS OF THE CWFA. THE WAA PRECIPITATION WING OF THE CLIPPER SYSTEM WILL MOVE ACROSS THE WESTERN HALF OR TWO THIRDS OF THE CWFA SATURDAY MORNING. CONDENSATION PRESSURE DEFICITS REMAIN LOW AND THERE IS F VECTOR CONVERGENCE WITH SOME FORCING. DURING THE AFTERNOON THE COLD CONVEYOR BELT PRECIPITATION FROM THE CLIPPER SYSTEM WILL OVERSPREAD THE ENTIRE AREA BEFORE ENDING FROM THE WEST LATE IN THE AFTERNOON. AS FOR AMOUNTS...A DUSTING OF ACCUMULATION IS POSSIBLE PRIOR TO SUNRISE IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA. ACCUMULATIONS DURING THE DAY SATURDAY SHOULD RANGE FROM A DUSTING TO ONE HALF INCH. IT IS CONCEIVABLE THAT ACCUMULATIONS APPROACHING AN INCH MAY OCCUR OVER THE SOUTHWEST THIRD TO HALF OF THE CWFA. ..08.. LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY... ACTIVE/UNSETTLED PATTERN TO PERSIST THROUGH THE PERIOD WITH MANY FCST CHALLENGES. MAIN STORM SYSTEM THAT BEARS CONSIDERABLE WATCHING IS IN MON-TUE TIME-FRAME. THIS STORM LOOKS TO BRING WINTRY MIX OF PCPN WITH POTENTIAL FOR HEADLINES. SAT NGT... SOME RESIDUAL WEAK LIFT LINGERS INTO THE EVE ACROSS THE NORTH AS CLIPPER DEPARTS AND WARM FRONT PUSHES THROUGH. NAM AND GFS BUFR SOUNDINGS SHOW LOSS OF ICE INTRODUCTION WHICH WOULD SUPPORT DRIZZLE OR FREEZING DRIZZLE. CONCERNS THOUGH THESE MODELS MAY BE OVERDONE WITH EXTENT OF LOW LEVEL MOISTURE ... A TYPICAL BIAS ESPECIALLY WITH NAM... ESPECIALLY GIVEN NO SNOW MELT. GIVEN UNCERTAINTIES AND WITH ANY PCPN JUST TRACE AMOUNTS HAVE LEFT OUT ANY MENTION ATTIM. MAY SEE TEMPS STEADY OR RISING OVRNGT ESPECIALLY SOUTH WITH ONSET OF LOW LEVEL WARM ADVECTION. SUN-SUN NGT... NEXT ARCTIC FRONT TO EMERGE INTO THE PLAINS AND EXPECTED TO PUSH THROUGH IA AND POSSIBLY BISECTING 12Z MON PER NAM/GFS. HI-RES ECMWF SLOWER BUT 12Z RUN IS SLIGHTLY FASTER AND MAY BE TRENDING TOWARD NAM/GFS. DEEPER MOISTURE RETURNS LATE FOR POSSIBLY SOME VERY LIGHT RAIN OR DRIZZLE AFTER MIDNIGHT... OR VERY LIGHT FREEZING RAIN/DRIZZLE IN SOME AREAS DEPENDING ON SFC TEMPS WITH NW CWA MOST SUSCEPTIBLE IT APPEARS ATTIM BUT THIS DEPENDENT ON FRONTAL TIMING. MOST IF NOT ALL OF AREA SHOULD GET ABOVE FREEZING WITH 40S WIDESPREAD ACROSS THE SW CWA ON GUSTY SOUTHERLY WINDS. MON-TUE... STRONG BAROCLINICITY AND COUPLED JET STRUCTURE SUPPORT CYCLOGENESIS ALONG ARCTIC FRONT... WITH CONSIDERABLE MODEL SPREAD ON MAGNITUDE/TRACK/TIMING... AND GIVEN HIGHLY DYNAMICAL ENVIRONMENT EXPECT CONTINUED CHANGES IN MODELS NEXT DAY OR TWO. GFS AND HI-RES ECMWF HAVE TRENDED DEEPER AND SLOWER... AND MAY CONTINUE TO SEE THIS TREND. BOTTOM LINE IS MOISTURE AND FORCING SUPPORTS MODERATE QPF EVENT NOT TOO DISSIMILAR FROM THIS MOST RECENT EVENT. DEPENDING ON FRONT AND SFC LOW LOCATIONS PCPN TYPES COULD VARY OR TRANSITION FROM RAIN TO FREEZING RAIN...SLEET AND SNOW ACROSS CWA. THEREFORE... WITH THE WINTRY MIXTURE THIS SYSTEM WILL BEAR CONSIDERABLE WATCHING IN THE DAYS AHEAD. POPS ARE IN MOD/HIGH CHC CATEGORY FOR NOW GIVEN UNCERTAINTY WITH TRACK. IN ADDITION MAY SEE FOG MON WITH AREAS OF DENSE FOG AHEAD OF SFC LOW WITHIN LOW LEVEL MOISTURE CONVERGENCE. WED-FRI... MUCH COLDER WITH ANOTHER ARCTIC FRONT SUGGESTED TO ARRIVE WED THAT MAY NEED POPS IN LATER FCSTS. FOR NOW THOUGH HAVE CHC POPS THU-FRI AS ENERGY RIPPLES ALONG LOW-MID LEVEL BAROCLINIC ZONE. WINTER HAS FINALLY ARRIVED. ..05.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
331 AM CST SAT JAN 14 2012 .DISCUSSION... SHORT RANGE (TODAY AND SUNDAY)... 09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST-NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY. MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)... THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH-SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS THAT DAY APPROACHES. JL && .AVIATION... WIND FORECAST REMAINS THE BIGGEST CHALLENGE WITH VFR CONDITIONS STILL EXPECTED. LOW PRESSURE TO MOVE SOUTHEAST THROUGH EASTERN NEBRASKA AND NORTHERN MISSOURI THROUGH 15Z WITH WINDS SHIFTING AS A RESULT. BACKED OFF THE NORTHWEST WIND TIMING A BIT WITH MIXING INTO THE DEEPER WINDS HOLDING OFF A BIT. WINDS COME BACK TO LIGHT SOUTHERLY IN THE 20Z-03Z PERIOD. 65 && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1022 PM MST FRI JAN 13 2012 .UPDATE... 646 PM MST FRI JAN 13 2012 LATEST RUC AND HRRR CATCHING INCOMING SURFACE TROUGH FROM THE NORTHWEST. THEY HAD THE STRENGTH/POSITION THE BEST WITH THE REMAINING MODEL OUTPUT NOT STRONG ENOUGH. SO INCREASED WIND SPEEDS OVER THE NORTHEAST PORTION OF THE AREA A LITTLE. ALSO BECAUSE OF THE STRONGER WINDS RAISED THE MINS SOME THAT SAME AREA AS WELL. OTHERWISE...JUST ADJUSTED HOURLY GRIDS. BULLER && .DISCUSSION... 208 PM MST FRI JAN 13 2012 TONIGHT...SHOULD SEE NORTHWEST WINDS OF 10 TO 20 MPH WINDS WITH HIGHER GUSTS THROUGH MIDNIGHT BEHIND A DEPARTING UPPER LEVEL DISTURBANCE. AFTER MIDNIGHT WINDS SUBSIDE A BIT INTO THE 10 MPH RANGE. OVERNIGHT LOWS WILL BE A BIT WARMER THEN THE PAST FEW NIGHTS AS WARM AIR ALOFT MOVES IN. WILL AIM FOR LOWS GENERALLY IN THE UPPER TEENS TO LOW 20S IN FAR EASTERN COLORADO...LOW TO MID 20S EAST OF THE CO/KS BORDER. THIS IS SEVERAL DEGREES WARMER THAN THE MAV AND MET MOS GUIDANCE. 007 SATURDAY-SUNDAY...H5 RIDGE CONTINUES TO BUILD EAST TOWARDS CWA...WITH DRY/STABLE AIR MASS IN PLACE THROUGH SUNDAY NIGHT. TEMPERATURES WILL CONTINUE TO MODERATE OVER THE NEXT FEW DAYS...WITH HIGH TEMPS IN THE 50S SATURDAY...AND MID/UPPER 50S ON SUNDAY. CONSIDERING TEMPS ALOFT SAT/SUN NIGHTS...BUMPED LOWS TO THE UPPER 20S. THIS IS ABOUT 5-10F ABOVE MOS GUIDANCE...HOWEVER CONSIDERING TEMPS ALOFT AND POSSIBLE SKY COVER SUN NIGHT...THIS MAY STILL BE TOO COOL. MONDAY-MONDAY NIGHT...TROUGH DEVELOPING OVER THE PACIFIC NW OVER THE WEEKEND WILL PROGRESS EAST ACROSS THE GREAT BASIN TOWARDS THE CWA MONDAY. GUIDANCE STILL DIFFERS BY ABOUT 6HR ON TIMING OF ASSOCIATED COLD FRONT MONDAY...HOWEVER OVERALL TREND HAS BEEN TO SPEED UP ARRIVAL...WITH FRONTAL PASSAGE LIKELY BY MIDDAY. PRECIP ASSOCIATED WITH LARGE SCALE ASCENT ALONG LEADING EDGE OF TROUGH AXIS LOOKS TO ARRIVE FROM THE NW LATE MONDAY AFTERNOON...QUICKLY MOVING EAST THROUGH THE EVENING HOURS. GUIDANCE IN GOOD AGREEMENT ON STABLE/DRY AIR QUICKLY MOVING IN AFTER 06Z...SO I TRENDED FORECAST IN THAT DIRECTION. I KEPT BEST CHANCES DURING THE EVENING IN THE NORTH...AND LEFT A SMALL AREA OF SLIGHT CHANCE POPS IN THE FAR EAST AFTER 06Z. CONSIDERING LIMITED MOISTURE AND QUICK NATURE OF THIS SYSTEM...ONLY ANTICIPATING LIGHT SNOW ACCUMULATIONS...ABOUT AN INCH OR LESS. TUESDAY-FRIDAY...REMAINING FORECAST LOOKS DRY WITH W/NW FLOW DEVELOPING ACROSS WESTERN CONUS...AND DRY/STABLE AIR MASS IN PLACE. BIGGEST QUESTION THROUGH THESE PERIODS WILL BE HOW QUICKLY SHALLOW COLD AIR MASS MODERATES...AND WHAT TEMPS WILL DO IN RESPONSE TO WEAK SHORTWAVE TROUGHS EMBEDDED WITHIN MEAN FLOW. FOR NOW EXPECT BELOW NORMAL TEMPS TUESDAY AND NEAR NORMAL TEMPS WEDNESDAY. GUIDANCE STILL INDICATING RISING H5 HEIGHTS H85 TEMPS TO ABOUT 10-12C BY FRIDAY...WHEN I KEPT FORECAST OF MID 50S IN THE WEST. THIS MAY END UP BEING TOO COOL CONSIDERING CONDITIONS ALOFT...HOWEVER THERE IS ENOUGH UNCERTAINTY IN REGARDS TO BOUNDARY LAYER DIFFERENCES TO KEEP ME FROM CHANGING TOO MUCH THIS FAR OUT. DR && .AVIATION... 1020 PM MST FRI JAN 13 2012 FOR THE 06Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SURFACE TROUGH WILL MOVE THROUGH THE AREA TONIGHT AND CAUSE SOME GUSTY WINDS...MAINLY AT KMCK. AFTER THAT...WINDS WILL GRADUALLY SHIFT THROUGH THE PERIOD AS THE SURFACE RIDGE MOVES EAST AND THE LEE TROUGH DEVELOPS. BULLER && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
127 AM CST SAT JAN 14 2012 .DISCUSSION... HAVE UPDATED FORECAST THIS MORNING FOR PRECIP TRENDS AS WELL AS TEMPERATURES. SHORTWAVE DIVING OUT OF THE DAKOTAS INTO CENTRAL NEB IS INDUCING FLURRIES OR LIGHT SNOW IN SOUTHEAST SD TO NORTHWEST/CENTRAL IA. NORTHWESTERLY FETCH OF AREAS OF SNOW HAS BEEN SKIRTING THE FRINGE OF THE CWA...AND OBS HAVE INDICATED NO VIS REDUCTIONS WITHIN THE CWA...WITH YKN AND DNS THE CLOSEST LOCATIONS RECEIVING ENOUGH LIGHT SNOW TO LOWER VIS. HAVE PULLED DOWN POPS SIGNIFICANTLY AWAY FROM THE NORTHERN AND EASTERN MARGINS OF THE CWA THIS MORNING...WITH JUST FLURRIES AFTER 09Z. ALSO TWEAKED TEMPERATURE CURVE THROUGH THE MORNING HOURS AS TEMPERATURES ARE BEGINNING TO RISE IN THE WESTERN CWA ON THE NOSE OF HIGHER WESTERLY WINDS. MAYES && .PREV DISCUSSION... /ISSUED 1124 PM CST FRI JAN 13 2012/ AVIATION... 06Z TAFS FOR KOFK...KOMA AND KLNK. SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z. THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA. CHERMOK PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/ SHORT TERM...TONIGHT THROUGH MONDAY. THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW MOVING IN FROM THE WEST MONDAY. AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY 20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY 12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING... SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST. ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA. MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END. ZAPOTOCNY LONG TERM...MONDAY NIGHT THROUGH FRIDAY. MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY HIGHS RANGED FROM 21 TO 49 AT OMAHA. LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING. THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY. THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS 6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST. ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE SOME LIGHT SNOW WITH THIS SCENARIO. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1124 PM CST FRI JAN 13 2012 .AVIATION... 06Z TAFS FOR KOFK...KOMA AND KLNK. SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z. THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA. CHERMOK && .PREV DISCUSSION... /ISSUED 521 PM CST FRI JAN 13 2012/ AVIATION... 00Z TAFS FOR KOFK...KOMA AND KLNK. CLIPPER-TYPE SYSTEM SHOULD MOVE QUICKLY INTO NERN NEBRASKA AROUND 14/06Z AND THEN INTO SERN MO BY 14/18Z. THIS SYSTEM WILL BRING A SHIFT TO GUSTY NORTHWEST WINDS LATE TONIGHT/EARLY SATURDAY... AND POSSIBLY A PERIOD OF LOWER CLOUDS AND SCATTERED SNOW SHOWERS. SNOW CHCS APPEARED SOMEWHAT BETTER AT KOFK AND KOMA. SURFACE WINDS SHOULD RELAX SATURDAY AFTERNOON BEFORE TURNING TO S/SW IN THE EVENING AHEAD OF YET ANOTHER SYSTEM. CHERMOK PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/ SHORT TERM...TONIGHT THROUGH MONDAY. THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW MOVING IN FROM THE WEST MONDAY. AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY 20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY 12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING... SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST. ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA. MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END. ZAPOTOCNY LONG TERM...MONDAY NIGHT THROUGH FRIDAY. MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY HIGHS RANGED FROM 21 TO 49 AT OMAHA. LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING. THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY. THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS 6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST. ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE SOME LIGHT SNOW WITH THIS SCENARIO. DERGAN AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL SITES THROUGH THE TAF PERIOD. A FRONTAL BOUNDARY WILL APPROACH THE CWA THIS AFTERNOON...BRINGING WINDS AROUND TO THE SOUTHEAST AHEAD OF THE FRONT. OVERNIGHT...WINDS BEHIND THE FRONT ARE EXPECTED TO INCREASE AND SWITCH TO THE NORTHWEST. ROUKE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
230 AM CST SAT JAN 14 2012 .DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL USE BLEND. BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY. FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN THE 20S. TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE. NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED 32 DEGREES. STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY TO RECOVER AT ALL MONDAY AND MAY EVEN DROP. .LONG TERM (TUE-FRI)... MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA. && .AVIATION... CIGS WILL CONTINUE TO FLOP BETWEEN VFR AND MVFR IN LIGHT SNOW BAND AREA ALONG SOUTHERN VALLEY INTO WESTERN MN THIS MORNING. EXPECT MORE VFR CONDITIONS ALONG AND WEST OF VALLEY. VSBYS IN -SN THIS MORNING WILL BE PRIMARILY VFR WITH SOME BRIEF MVFR IN HEAVIER SNOW SHOWERS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER/JIMMY K
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
406 AM EST SAT JAN 14 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM. A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH. BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK SNOW WARN. WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE NORMAL FOR THE SECOND WEEK OF JANUARY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO STAY JUST SUB-NORMAL THRU THE SHORT TERM PD. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY INCH OR TWO. THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE. THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF INTERSTATE 80. THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU BY LATER SUNDAY NIGHT. MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB TO PLUS 3-6C ACROSS MUCH OF THE CWA. THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH AHEAD OF AN APPROACHING CFRONT. COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY NIGHT. NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... 09Z UPDATE...NO CHANGES TO 06Z SCHEDULED ISSUANCE. COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN 15-25KTS WILL BE COMMON THRU MOST OF THE DAY. OUTLOOK... SUN...MVFR CIGS WEST...BCMG VFR. MON...VFR. MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST. TUES...MVFR AND IFR LKLY IN RA/SN. WED...WINDY. MVFR AND IFR -SHSN W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...LAMBERT/STEINBUGL AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
134 AM EST SAT JAN 14 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /THROUGH TODAY/... CONVERGANCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM. A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENRITES IN THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP SNOW AMOUTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH. BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK SNOW WARN. WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE NORMAL FOR THE SECOND WEEK OF JANUARY. && .SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/... HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H FLOW DOESNOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO STAY JUST SUB-NORMAL THRU THE SHORT TERM PD. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY INCH OR TWO. THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE. THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF INTERSTATE 80. THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU BY LATER SUNDAY NIGHT. MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB TO PLUS 3-6C ACROSS MUCH OF THE CWA. THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH AHEAD OF AN APPROACHING CFRONT. COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY NIGHT. NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN 15-25KTS WILL BE COMMON THRU MOST OF THE DAY. OUTLOOK... SUN...MVFR CIGS WEST...BCMG VFR. MON...VFR. MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST. TUES...MVFR AND IFR LKLY IN RA/SN. WED...WINDY. MVFR AND IFR -SHSN W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...LAMBERT/STEINBUGL AVIATION...FITZGERALD/STEINBUGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1030 PM CST FRI JAN 13 2012 .DISCUSSION.../ISSUED AT 750 PM CST/ AREA OF LIGTH SNOW IN THE JAMES VALLEY CONTINUES TO FILL IN ASSOCIATED WITH SOME 800-900MB FRONTOGENESIS. LATEST RUC SHOWS THAT THIS TREND SHOULD CONTINUE THROUGH 06Z...SPREADING INTO THE I-29 CORRIDOR...THEN PULLING EASTWARD INTO MN AND IA AFTER 06Z THEN EAST OF THE FORECAST AREA BY 12Z. AMOUNTS STILL LOOK TO BE RATHER LIGHT WITH ONE HALF INCH OR LESS EXPECTED. OTHERWISE...STEADY TO SLOWLY RISING TEMPERATURES OVERNIGHT AS FORECAST EARLIER STILL LOOK ON TRACK. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ VFR THROUGH MOST OF THE PERIOD...WITH OCCASIONAL MVFR CEILINGS AND VISBILITIES THROUGH 12Z AS LIGHT SNOW MOVES SOOUTHEAST ACROSS THE REGION. LOWER CLOUDS SHOULD DISSIPATE AFTER 12Z AND NORTHWEST WINDS OF 15 TO 20 MPH WILL DEVELOP ON SATURDAY AND THEN BECOME LIGHT TOWARDS SUNSET. && .PREVIOUS DISCUSSION.../ISSUED AT 300 PM CST/ LATEST WATER VAPOR LOOP SHOWING A FAIRLY STRONG WAVE DIGGING INTO EASTERN MONTANA LATE THIS AFTERNOON WHICH WILL BRING THE SHOT OF LIGHT SNOW TO THE AREA TONIGHT. STRONGER BAROCLINICITY CONFINED TO THE LOWEST LEVELS OF THE ATMOSPHERE AND DO NOT EXPECT THIS TO PLAY A BIG ROLE IN PRECIPITATION PRODUCTION. HIGHER UP...AROUND 700MB...NOT MUCH OF A THERMAL GRADIENT SO AT LEAST WITH THIS EVENT PLANNING ON FOLLOWING THE UPPER LEVEL PV ADVECTION AS WELL AS THE 750-650MB THETA E RIDGING. THIS WILL BRING A CHANCE FOR SNOW INTO CENTRAL SOUTH DAKOTA BETWEEN 0Z AND 3Z WITH AN INCREASING CHANCE ACROSS CENTRAL PARTS OF THE CWA FROM ABOUT 3Z THROUGH 9Z...THEN LIKELY PEELING INTO NORTHWEST IOWA FROM ABOUT 6Z THROUGH 12Z. NOT PLANNING ON TOO MUCH ACCUMULATION WITH MOST LOCATIONS AN INCH OR LESS. TEMPERATURES WILL REMAIN STEADY TO RISING THROUGH THE NIGHT AS WELL WITH MORNING TEMPERATURES ABOUT 20 DEGREES WARMER THAN THIS MORNING. BY SATURDAY THE BULK OF THE ACTIVITY SHOULD BE EAST OF THE AREA WITH A MARGINALLY BREEZY NORTHWEST DEVELOPING. HIGHS MOSTLY UNCHANGED FROM EARLIER...RANGING FROM NEAR 30 IN THE NORTHERN CWA TO THE UPPER 30S IN THE SOUTH. A SURFACE RIDGE SLIDES QUICKLY TO THE EAST ON SATURDAY NIGHT...WITH A SOUTHERLY FLOW RETURNING TO THE AREA DURING THE NIGHT TIME HOURS OUT AHEAD OF A TROUGH PUSHING OUT OF THE NORTHERN ROCKIES. WITH THIS...TEMPERATURES WILL BE TRICKY ON SATURDAY NIGHT...INITIALLY DROPPING PRETTY QUICKLY...THEN STEADYING OUT AND RISING IN SOME AREAS OVERNIGHT WITH LOW LEVEL WARM AIR ADVECTION AND AN INCREASING GRADIENT. LOWS EARLY LOOKING TO BE IN THE UPPER TEENS TO LOWER 20S. SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVERAL OUT AHEAD OF THE APPROACHING SURFACE TROUGH. THOUGH WITH SOME MODEL DIFFERENCES...MIXING LOOKS TO BE AROUND 925 MB...WHERE TEMPERATURES WILL BE APPROXIMATELY IN THE RANGE OF 1 TO 7 DEGREES C FROM NORTH TO SOUTH...AND HIGHS WILL BE FROM LOWER 40S NORTH OF THE INTERSTATE 90 CORRIDOR TO AROUND 50 FROM LAKE ANDES TO SIOUX CITY TO STORM LAKE. COLD FRONT DROPS SOUTHWARD ACROSS THE REGION ON SUNDAY NIGHT BRINGING AND END TO THE WARMTH...WITH LOWS IN THE UPPER TEENS TO MID 20S. CONFIDENCE IN MONDAY/MONDAY NIGHT DETAILS RATHER LOW...WITH MODELS SPLIT IN THE DETAILS REGARDING TIMING AND PLACEMENT OF MIDLEVEL THERMAL GRADIENT AND SHORTWAVE TRACKING ACROSS THE CENTRAL PLAINS DURING THAT TIME FRAME. DOES LOOK LIKE THERE WILL BE A PERIOD OF LIGHT SNOW ACROSS THE AREA SOMETIME LATER ON MONDAY AND MONDAY NIGHT...WITH MAYBE AN INCH TO INCH AND HALF OR SO OF ACCUMULATION POSSIBLE AT THIS POINT. WILL BE SOMETHING TO WATCH HOWEVER. WITH COLD AIR ADVECTION MONDAY WILL BE COLDER WITH HIGHS MAINLY IN THE 20S. IN THE EXTENDED...TUESDAY THROUGH FRIDAY...APPEARS TO BE GENERALLY COLD THROUGH THE PERIOD AS A SERIES OF REINFORCING SHORTWAVES TRACK ACROSS THE NORTHERN PLAINS/UPPER MIDWEST IN A NORTHWESTERLY UPPER LEVEL FLOW. CANNOT RULE OUT A COUPLE PERIODS OF LIGHT SNOW DURING THAT TIME FRAME...THOUGH HARD TO PIN DOWN WITH USUAL MODEL DIFFERENCES. TUESDAY AND THURSDAY LOOKING TO BE THE COLDEST DAYS...IN THE TEENS...WARMING TO 20S TO LOWER 30S BY FRIDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
630 AM EST SAT JAN 14 2012 .SYNOPSIS... A COLD FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA TODAY AND TONIGHT. COLD HIGH PRESSURE FROM THE WEST IS EXPECTED TO INFLUENCE OUR WEATHER FOR SUNDAY AND SUNDAY NIGHT BEFORE PASSING OUT TO SEA ON MONDAY. A WARM FRONT FROM THE WEST AND SOUTHWEST IS ANTICIPATED TO WORK ITS WAY THROUGH OUR REGION ON TUESDAY, FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT. AN AREA OF HIGH PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY NIGHT OR FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A 10Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO THE UPPER OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST. A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY. THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW- LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND. THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. SOME WEAK SHORT WAVE ENERGY IS HELPING TO PRODUCE SOME FLURRIES OR A FEW SNOW SHOWERS ACROSS MAINLY THE POCONOS EARLY THIS MORNING. SOME SLIGHT CHC POPS WERE USED EARLY THIS MORNING, THEN WE LEANED TOWARD THE NAM/WRF FOR POPS WHICH PLACES POPS IN THE SLIGHT CHC TO CHC RANGE MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE-HALF INCH OF SNOW ACCUMULATION ACROSS THE POCONOS. ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS. THE TAIL END OF A WEAK SHORT WAVE IS HELPING TO GENERATE A SWATH OF MAINLY MID LEVEL CLOUDS ACROSS THE SOUTHEASTERN ZONES EARLY THIS MORNING. SOME RETURNS HAVE BEEN SHOWING UP ON RADAR ACROSS NORTHEASTERN MARYLAND TO SOUTHWESTERN NEW JERSEY. PERHAPS A FEW FLURRIES REACH THE GROUND, BUT OVERALL THIS LOOKS TO BE MID LEVEL MOISTURE ONLY. BACK TO THE STRATOCUMULUS, THIS WILL BE AROUND TODAY ESPECIALLY ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY AS THE WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN INVERSION. THE FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER CLOSE TO THE CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER LEVELS BEING RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME STRATOCUMULUS BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA, WHICH MAY RESULT IN VARYING CLOUD COVER THROUGH THE DAY. BASED ON SATELLITE TRENDS AS OF 11Z, WE INCREASED THE SKY COVER FARTHER EAST FOR AWHILE THIS MORNING. A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED BLEND OF THE MOS GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH AND EAST OF THE PHILADELPHIA METRO AREA. AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE AREA. AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER LOCALES. && .LONG TERM /SUNDAY THROUGH FRIDAY/... MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS. THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID LEVEL CLOUDS. ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT WILL SUPPORT ALL RAIN ON MONDAY NIGHT. AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES. ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE FORECASTING. A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT NORMAL FOR THIS TIME OF THE YEAR. A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW- LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE TAFS AT THIS TIME. THE COLD WESTERLY FLOW COMBINED WITH SOME WEAK ENERGY MOVING THROUGH AND ENOUGH MOISTURE TRAPPED UNDER AN INVERSION, IS HELPING TO PULL STRATOCUMULUS DOWN ACROSS MOST OF THE AREA ALONG WITH MID LEVEL CLOUDINESS. THIS IS EXPECTED TO CONTINUE WITH AT LEAST BROKEN CEILINGS AROUND 4,000 FEET, ESPECIALLY FROM THE KPHL METRO AREA ON NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME WITH GUSTS DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS MORNING. ALL OF OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN THE 20-25 KNOT RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER IN THE AFTERNOON AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD MAINTAIN SOME STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT AS IT DROPS SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO TURN THE SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT. OUTLOOK... DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG, KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE, KILG, KMIV AND KACY. A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER SHOULD FOLLOW FOR WEDNESDAY. && .MARINE... AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW. A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED TONIGHT AS HIGH PRESSURE EDGES CLOSER. WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL CONDITIONS. WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET. A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER, GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430- 431-450>455. && $$ SYNOPSIS...IOVINO NEAR TERM...GORSE SHORT TERM...GORSE LONG TERM...IOVINO AVIATION...GORSE/IOVINO MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION...updated for aviation section
NWS TALLAHASSEE FL
535 AM EST Sat Jan 14 2012 .SYNOPSIS... 08Z water vapor and H4 RUC analysis shows an upper level pattern consisting of longwave troughing over much of the inter-mountain west, followed downstream by longwave troughing over much of the CONUS east of the continental divide. A series of shortwaves beginning to arrive along the British Columbia coastline will slowly break down the western U.S. ridge during the upcoming weekend which will lead to eventual height rises and an overall warmup for the eastern states by the early portion of next week. For now however, watching a shortwave impulse rounding the base of the main eastern trough over the SE states early this morning. The trough axis is just now exiting east of our area, seen with an expanding area of subsidence/drying overhead on WV imagery. A final piece of energy is sliding down the backside of the trough through the mid-section of the country. This energy will slide to our north tonight allowing height rises in its wake for Sunday. At the surface, 1028mb high pressure centered along the TX/LA coasts continues to build east into our forecast area. As the ridge expands eastward, the local gradient has been slowly weakening allowing for an increasingly efficient radiational cooling setup. Still anticipate a widespread light freeze by sunrise away from the immediate coast. A few isolated and normally colder locations may still briefly reach hard freeze criteria in the hour or two surrounding sunrise. && .SHORT TERM (TODAY THROUGH MONDAY)... Today, Subsidence behind the departing shortwave this morning will help promote mostly sunny skies through the day. However, a slight re-enforcing shot of CAA...especially above the surface will keep temperatures a bit below normal. At the surface, high pressure will continue to expand eastward with a high center forming over the coastal waters by the later afternoon/evening hours. To our north, a weak surface reflection/low associated with the final shortwave impulse will translate quickly from MO this afternoon, to the TN valley this evening. Associated with this feature will be a weak cold front that will cross northern AL/GA and into the Carolinas. Although this cold front will not directly pass through our area, it will have an influence of somewhat tightening the gradient over our northern zones later today/this evening. The tighter gradient may have an impact on temperatures tonight. Before that, afternoon temps today are expected to top out in the mid/upper 50s. Tonight, As mentioned above, some uncertainly with regards to temperatures relating to how rapidly the gradient will collapse again over our northern/NE zones in the wake of a passing cold front/trough. The impact looks to be least along and south of the I-10 corridor where proximity to the eastward extension of the surface ridge should set up good radiational cooling conditions early. The temperatures drop may be slower this evening further to the north, however the GFS/ECMWF both show a quick exit of the trough and the potential for late night de-coupling. Therefore, will not deviate far from a MET/MAV blend for overnight lows. Generally looking for lows in the low/mid 30s inland and mid/upper 30s at the coast. Does appear that any location which do reach or drop just below freezing will not do so until right around sunrise, with a fairly short duration of near freezing temps. If the tighter gradient holds longer than numerical guidance currently suggest, then low temps would not be quite as cold for areas north of KTLH and KVLD. Sunday/Sunday night, Very pleasant day upcoming for the second half of the weekend. Rising heights over-top a strong surface ridge will provide the region with dry and seasonable conditions. Winds will be on the light side, which will slow the overall diurnal mixing, however should still be able to reach afternoon highs very close to climatology in the 59-64 range. Sunday night the surface ridge will exit to our east allowing a slow increase in gradient and also low level moisture. Current guidance still suggest a cool overnight with lows in the mid 30s inland to the low 40s at the coast. Monday, Stacked ridging will allow temperatures to finally rise above normal for most locations. Still not anticipating all that efficient a mixing environment, and therefore will likely not realize the full potential of the column that 850mb temps around 10C would suggest. However, not too many will be complaining as temps rise into the upper 60s to near 70 under partly sunny skies. The SE/S flow is likely to keep immediate coastal areas a bit cooler, especially along the Apalachee Bay coastline where shelf water temps are in the upper 50s. && .LONG TERM (Monday Night through next Friday)... The large scale longwave pattern commences fairly amplified. This is highlighted in the Nrn stream by troughing across Plains and weak ridging in between. Srn stream with weak troughing Desert SW and weak ridging elsewhere. At surface, high along Carolina coast ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front Swwd across Wrn TN Valley and into TX. During the rest of the period, Plains upper trough digs rapidly SEWD accompanied by shortwave and merges with Desert SW Trough crossing the Nrn Gulf Tues into Tues night. In response, Srn stream upper ridge shunted offshore. At surface, this trough pushes surface low to Srn Great Lakes kicking high further into Atlc. Assocd cold front with limited instability dragged rapidly Sewd with deep sly flow setup from Gulf. GFS and ECMWF similar in timing and intensity of front, but both noticeably slower than 24 hrs ago, pushing thru Wrn CWA late Tues night exiting Ern most zones Wed morning bringing sct shwrs and possibly a few tstms. Trough pushes into Atlc beginning Wed night. In its wake, NWLY to weakly zonal steering flow once again dominates local area as strong high builds SEWD from Srn Plains spreading a reinforcing shot of cold and very dry offshore air across local region Wed into late Thurs. However coldest air remains well to our north so not expecting a solid freeze event. By early Fri, models consistent with next albeit weak shortwave that helps developing surface low which moves moves newd into Lwr MS Valley dragging trailing cold front to Wrn Gulf. Locally, this pushes the dry airmass EWD and high offshore increasing onshore flow and clouds beginning Fri night. Forecast will show low-mid sct pops Tues aftn especially NW third expanding everywhere on Wed morning down to wdly sct-low sct Wed aftn. Otherwise nil pops thru period. Ahead of the front min temps will be around 10 degrees above climo Mon and Tues nights dropping to at or below climo Wed night and may reach freezing in coldest locales then inching to slightly above climo on Thu night. Max temps commence at least 10 degrees above climo on Tues dropping to at or slightly above climo on Wed then inching up to a few degrees each day thru Fri. Average inland min/max temps are 39/62 && .MARINE... High pressure will build over the coastal waters today allowing winds and seas to subside. A brief surge of westerly winds may approach cautionary levels overnight into early Sunday morning before quickly diminishing by the afternoon. The ridge of high pressure will then move east of our region Sunday night allowing winds to come around to the east and southeast and increase to moderate levels for the early portion of next week. A weak cold front is schedule to cross the northeast Gulf Tuesday night or Wednesday with a shift back to offshore flow in its wake. && .AVIATION (through 12Z Sunday)... VFR Conditions with mainly clear skies through the period. Calm winds increase to west to northwest around 5 mph after sunrise, then calm again after sunset. && .FIRE WEATHER... Expect a faster warmup and higher afternoon temperatures today compared to yesterday. Therefore with a persistent dry airmass expect around 4 hour durations of RH below 25% in our Alabama and Georgia zones, altho ern counties of GA iffy. But...with warning already in effect will elect to keep it everywhere and have day shift reevaluate. For our Florida zones, altho critical humidities will be realized, latest dispersions as well as ERC and 20 foot winds should remain under critical levels. Therefore inherited watch has been discontinued. Airmass should moisten slightly on Sunday precluding red flag conditions over AL/GA. Once again low humidities in FL will be offset by ERC...dispersion and winds below critical levels. Red flag conditions are not anticipated during the upcoming work week. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 57 32 62 33 68 / 0 0 0 0 0 Panama City 57 40 62 43 61 / 0 0 0 0 0 Dothan 59 35 59 36 69 / 0 0 0 0 0 Albany 57 32 59 34 70 / 0 0 0 0 0 Valdosta 56 33 60 35 68 / 0 0 0 0 0 Cross City 58 31 64 34 70 / 0 0 0 0 0 Apalachicola 56 36 61 41 60 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for Coffee-Dale-Geneva-Henry-Houston. GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay- Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier- Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole- Terrell-Thomas-Tift-Turner-Worth. FL...None. GM...None. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
921 AM CST SAT JAN 14 2012 .DISCUSSION... ISSUED 921 AM CST SAT JAN 14 2012 15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED. BARNES && .AVIATION... ISSUED 530 AM CST SAT JAN 14 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT. EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z. THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES. WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN. AUTEN && .PREV DISCUSSION... ISSUED 235 AM CST SAT JAN 14 2012 LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY. HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN SHEARING OUT OVER THE CENTRAL PLAINS. PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY. SHORT TERM...TODAY THROUGH TUESDAY... SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH. SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY. LONG TERM...WEDNESDAY THROUGH FRIDAY... FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN THE PERIOD. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
530 AM CST SAT JAN 14 2012 .DISCUSSION... ISSUED 235 AM CST SAT JAN 14 2012 LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY. HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN SHEARING OUT OVER THE CENTRAL PLAINS. PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY. SHORT TERM...TODAY THROUGH TUESDAY... SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH. SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY. LONG TERM...WEDNESDAY THROUGH FRIDAY... FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN THE PERIOD. GEELHART && .AVIATION... ISSUED 530 AM CST SAT JAN 14 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT. EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z. THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES. WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
522 AM CST SAT JAN 14 2012 ...UPDATE TO AVIATION... && .AVIATION... VFR ANTICIPATED THROUGH THE PERIOD. WINDOW OF GUSTY WINDS NORTHWEST BEGINS AROUND TAF ISSUANCE AND CONTINUES INTO THE EARLY AFTERNOON HOURS. CIGS NEAR 3KFT AGL EXPECTED TO BE SLIGHTLY HIGHER AND NOT A SOLID DECK AS THEY MOVE OVER TOP/FOE/MHK BUT WILL MONITOR FOR UPDATES. WINDS DROP BLO 12KTS 20-21Z THEN BECOME WESTERLY TO SOUTHWESTERLY THIS EVENING AND OVERNIGHT. 67 && .PREV DISCUSSION... /ISSUED 331 AM CST SAT JAN 14 2012/ SHORT RANGE (TODAY AND SUNDAY)... 09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST- NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY. MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)... THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH- SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS THAT DAY APPROACHES. JL && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
800 AM EST SAT JAN 14 2012 .SYNOPSIS... COLD UPPER LEVEL LOW PRESSURE, PASSING SLOWLY EASTWARD THROUGH THE GREAT LAKES, WILL MAINTAIN COLD CONDITIONS AND LIGHT SNOW SHOWERS TODAY. MIDWEST HIGH PRESSURE WILL PROVIDE A DRY SUNDAY AND EARLY MONDAY. CANADIAN LOW PRESSURE WILL FIRST BRING A WARM UP WITH RAIN SHOWERS LATE MONDAY AND TUESDAY, FOLLOWED BY A COOL DOWN WITH SNOW SHOWERS TUESDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED FOR MINOR ADJUSTMENTS TO POPS. RECENT SATELLITE DATA SHOWS CLOUD TOPS WARMING AND LIKEWISE RECENT RADAR AND SURFACE DATA SHOW SNOW FALL RATES HAVE DECREASED. WITH HRRR AND NAM MODEL OUTPUT SHOWING LITTLE SNOW REJUVENATION, EXPECT SLOW DECREASE THIS MORNING, WEST TO EAST, WITH PERHAPS A DRY BREAK BY AFTERNOON. SNOW ACCUMULATIONS WILL BE MINIMAL. PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES THIS AFTERNOON TO CLIMB TO HIGHS THAT WILL STILL BE 7 TO 12 DEGREES COLDER THAN NORMAL. NAM MODEL PROFILES SHOW WINDS DECREASING TO NORMAL VALUES BY AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... RECENT SREF MODEL OUTPUT SHOWS ONE MORE UPPER LEVEL TROUGH PASSING THROUGH THE UPPER OHIO VALLEY THIS EVENING. EXPECT MAINLY ISOLATED SNOW SHOWERS ACROSS THE MOUNTAINS WITH NO MORE THAN FLURRIES ELSEWHERE. AS UPPER TROUGH EXITS EAST, MIDWEST HIGH PRESSURE ENSUES TO PROVIDE A DRY SUNDAY. PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES TONIGHT TO YIELD LOWS 5 TO 8 DEGREES COLDER THAN NORMAL. HIGHS SUNDAY MAY BE SLIGHTLY WARMER THAN TODAY, BUT STILL GENERALLY ABOUT 5 TO 8 DEGREES COLDER THAN NORMAL. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... RECENT SREF MODEL OUTPUT SHOWS HIGH PRESSURE MAINTAINING DRY CONDITIONS SUNDAY NIGHT INTO MONDAY. BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS THE ROBUST UPPER LEVEL JETSTREAM ACROSS NORTH AMERICA WILL THEN STEER A LOW PRESSURE SYSTEM EASTWARD THROUGH THE GREAT LAKES AND MIDWEST MONDAY NIGHT INTO WEDNESDAY. WEST TO SOUTHWEST WINDS AHEAD OF THE SYSTEM`S COLD FRONT WILL PROVIDE A WARM UP MONDAY, SO THE INITIAL PRECIPITATION TYPE SHOULD BE RAIN SHOWERS MONDAY NIGHT AND TUESDAY. MODELS THEN SHOW A POST FRONTAL COOL DOWN WITH SNOW SHOWERS TUESDAY NIGHT INTO POSSIBLY WEDNESDAY. ANOTHER CANADIAN COLD FRONTAL PASSAGE MAY PROVIDE SNOW SHOWERS THURSDAY. REGARDING TEMPERATURE DETAILS, BLEND OF RECENT GFS MOS AND NAEFS MEDIAN VALUES SHOW THE WARM UP MONDAY INTO TUESDAY TO YIELD VALUES 10 TO 15 DEGREES WARMER THAN NORMAL. THE POST FRONTAL COOL DOWN STARTING TUESDAY NIGHT WILL YIELD VALUES 5 TO 10 DEGREES COLDER THAN NORMAL, THAT COULD LAST INTO FRIDAY. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... EXPECT MAINLY MVFR CONDITIONS INTO TONIGHT, MAINLY DUE TO STRATOCUMULUS CEILINGS. AS ONE UPPER LEVEL SHORT-WAVE TROUGH EXITS EAST, RECENT SATELLITE DATA SHOWS WARMING TOPS AND SURFACE AND RADAR DATA SHOW SNOW FALL RATES HAVE SLOWED. SO VISIBILITIES CAN BE UNRESTRICTED AT TIMES TODAY. A SECOND UPPER LEVEL SHORT-WAVE TROUGH CAN PASS EASTWARD THROUGH THE UPPER OHIO VALLEY THIS EVENING. THIS MAY CAUSE SCATTERED LIGHT SNOW SHOWERS WITH VISIBILITIES POSSIBLY RESTRICTED. SURFACE WINDS WILL BE MAINLY WEST SOUTHWEST NEAR 10 KTS WITH GUSTS TO 20 KTS INTO MIDDAY. OUTLOOK...SUNDAY THROUGH WEDNESDAY... EXPECT MAINLY VFR SUNDAY INTO MIDDAY MONDAY. NEXT CHANCE OF RESTRICTIONS WILL BE LATE MONDAY INTO WEDNESDAY FROM MIXED PRECIPITATION ASSOCIATED WITH A LOW PRESSURE SYSTEM PASSING EASTWARD THROUGH THE GREAT LAKES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1002 AM CST SAT JAN 14 2012 .DISCUSSION... MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID 20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA. && ,AVIATION... CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW. && .PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/ DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL USE BLEND. BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY. FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN THE 20S. TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE. NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED 32 DEGREES. STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY TO RECOVER AT ALL MONDAY AND MAY EVEN DROP. LONG TERM (TUE-FRI)... MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/VOELKER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
642 AM EST SAT JAN 14 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM. A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH. BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK SNOW WARN. WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE NORMAL FOR THE SECOND WEEK OF JANUARY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO STAY JUST SUB-NORMAL THRU THE SHORT TERM PD. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY INCH OR TWO. THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE. THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF INTERSTATE 80. THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU BY LATER SUNDAY NIGHT. MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB TO PLUS 3-6C ACROSS MUCH OF THE CWA. THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH AHEAD OF AN APPROACHING CFRONT. COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY NIGHT. NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... SFC ANALYSIS SHOWS A SECONDARY ARCTIC FRONT ACRS CNTRL NY THIS MRNG...WHICH WILL SINK SWD INTO NRN PA THIS AFTN. HI RES MDL GUID SHOWS LOW LEVEL CONVERGENCE ALONG THE FRONT HELPING TO ORGANIZE A LONG-FETCH LAKE EFFECT BAND NEAR ERI-BFD-IPT LINE THIS AFTN. THE EXACT LOCATION OF WHERE THE BAND WILL FORM AND HOW FAR SOUTH IT WILL PROPAGATE IS STILL UNCERTAIN...BUT GIVEN THE CONSENSUS OF THE HI RES DATA INDICATING PROXIMITY OF NRN TIER OF PA - REDUCED IPT VIS TO MVFR AT 18Z. UNV MAY ALSO BE IMPACTED LATER TDY BUT FOR NOW KEPT VIS VFR. OVERALL THERE ARE NO SIGNIFICANT CATEGORICAL CHANGES TO 09Z INTERMEDIATE TAFS FOR THE 12Z SCHEDULED ISSUANCE. COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW SHOWERS. THE WORST FLYING CONDS WILL PERSIST ACROSS THE WRN MTNS...WHERE VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES IN MOST AREAS...WITH MVFR CIGS BCMG VFR AT UNV/AOO AND LOW END SCT-BKN VFR CIGS AT LNS/MDT/IPT. SFC WNDS WILL GRADUALLY VEER MORE TO THE WNW INTO TONIGHT. OUTLOOK... SUN...MVFR CIGS WEST...BCMG VFR. MON...VFR BCMG MVFR MON NGT. LGT WINTRY MIX TO RAIN. TUES...MVFR/IFR. STG FROPA WND SFT. GUSTY WINDS. -RA TO -SHSN. WED...MVFR/IFR -SHSN WEST/VFR EAST. WINDY. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...LAMBERT/STEINBUGL AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1136 AM CST SAT JAN 14 2012 .DISCUSSION... ISSUED 921 AM CST SAT JAN 14 2012 15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED. && .AVIATION... ISSUED 1136 AM CST SAT JAN 14 2012 LIGHT SNOW WILL CONTINUE TO IMPACT MOST OF THE TAF SITES FOR THE NEXT COUPLE OF HOURS...BEFORE GRADUALLY COMING TO AN END BY MID-AFTERNOON. WILL HANG ON TO LIGHT SNOW THROUGH 19Z/20Z ACCORDINGLY...EXCEPT AT KPIA WHERE THE SNOW HAS ALREADY ENDED. CEILINGS WILL HOVER AROUND 3000FT AT THE I-72 TERMINALS UNTIL THE SNOW ENDS...THEN WILL CLIMB INTO THE VFR CATEGORY LATER THIS AFTERNOON. A SECONDARY UPPER-LEVEL WAVE CURRENTLY PUSHING INTO IOWA WILL SKIRT THROUGH THE REGION TONIGHT...BRINGING A PERIOD OF LOWER CEILINGS AND PERHAPS A FEW SNOW FLURRIES. HAVE LOWERED CEILINGS BACK DOWN TO AROUND 3000FT AT KPIA BY 03Z...THEN FURTHER EAST AT KCMI BY 08Z. ONCE THIS WAVE PASSES...MID-LEVEL CLOUD COVER WILL PERSIST THROUGH 18Z SAT. WINDS WILL INITIALLY BE LIGHT/VARIABLE THIS AFTERNOON AND TONIGHT...THEN WILL BECOME SOUTHERLY AT AROUND 10KT SUNDAY MORNING. BARNES && .PREV DISCUSSION... ISSUED 235 AM CST SAT JAN 14 2012 LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY. HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN SHEARING OUT OVER THE CENTRAL PLAINS. PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY. SHORT TERM...TODAY THROUGH TUESDAY... SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH. SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY. LONG TERM...WEDNESDAY THROUGH FRIDAY... FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN THE PERIOD. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
330 PM CST SAT JAN 14 2012 .SYNOPSIS... A COUPLE OF CLIPPER TYPE SYSTEMS WERE RESPONSIBLE FOR SOME LIGHT SNOW OVER THE REGION THIS MORNING AND THIS AFTERNOON. THE SURFACE LOW ASSOCIATED WITH ONE OF THE SYSTEM PASSED JUST TO OUR SOUTH THIS MORNING SPREADING SOME LIGHT SNOW OVER THE SOUTHERN COUNTIES. ANOTHER LOW WAS MOVING THOUGH NORTHERN MN EARLY THIS AFTERNOON WITH A WARM FRONT EXTENDING SOUTH INTO WESTERN IOWA. SOME LIGHT SNOW AND FLURRIES WERE OCCURRING JUST AHEAD OF THE FRONT. THE CLIPPER TYPE SYSTEMS WERE EMBEDDED IN NORTHWEST FLOW BOUNDED BY A LARGE TROF OVER THE GREAT LAKES AND OHIO VALLEY AND RIDGING OVER THE ROCKIES. ANOTHER VIGOROUS S/W WAS MOVING INTO BRITISH COLUMBIA AND THE PACIFIC NW WITH 200 METER 12 HOUR HEIGHT FALLS NOTED ON THE MORNING 500MB ANALYSIS. && .SHORT TERM...TONIGHT AND SUNDAY... THE NORTHERN MN LOW AND ITS ASSOCIATED WARM FRONT WEAKEN THIS EVENING AS LOW LEVEL FLOW OVER THE CENTRAL AND NORTHERN PLAINS BACKS AHEAD OF THE PACIFIC NW S/W AND ITS STRONGER SURFACE LOW MOVING INTO SOUTHERN SASKATCHEWAN BY SUNDAY MORNING. THE LIGHT SNOW AHEAD OF THE WARM FRONT HAS BEEN STEADILY WEAKENING AS IT MOVED OVER CENTRAL IOWA THIS AFTERNOON. THE CONTINUATION OF THIS WEAKENING TREND IS SUPPORTED BY LOW/MID LEVEL FGEN DECREASING OVER IA AND BECOMING MORE FOCUSED TO OUR NORTH THIS EVENING. RECENT HRRR RUNS ALSO SUPPORT A BETTER THREAT OF MEASURABLE SNOW NORTH OF THE CWFA. HAVE CUT POPS BACK TO SLIGHT CHANCE AT MOST...AND LIMITED THOSE TO THE NORTHEAST THIRD OF THE FORECAST AREA FOR THIS EVENING. AFTER MIDNIGHT EXPECT PARTLY TO MOSTLY CLOUDY SKIES WITH MID LEVEL WAA ADVECTION CLOUDS MOVING THROUGH THE AREA AS WELL AS SOME CI SPREADING IN WITH THE FORECAST AREA IN THE VICINITY OF THE RIGHT ENTRANCE REGION OF AN H3 JET STREAK FROM MN/WI INTO NRN IN AT 12Z SUNDAY. SOME FLURRIES WERE CONSIDERED IN THE WEST WITH THE MID LEVEL WAA...BUT PRESSURE CONDENSATION DEFICITS WERE QUITE HIGH BELOW 400MB...SO OPTED NOT TO MENTION FLURRIES. TEMPERATURES WILL BE DIFFICULT WITH THE SNOW COVER...LIGHT WINDS AND PATCHY NATURE OF THE CLOUDS. ANY CLEARING WILL ALLOW TEMPERATURES TO PLUMMET OVER THE NORTH. LATEST TIMING OF THE CENTRAL IA CLOUDS INTO/THROUGH THE CWFA SUGGEST THEY WILL NOT REACH THE EASTERN COUNTIES UNTIL A FEW HOURS AFTER SUNSET SO ALLOWED FOR A SIGNIFICANT DROP EARLY THIS EVENING IN NW IL WITH MINS IN THE SINGLE DIGITS. SUNDAY THE REGION WILL BE DOMINATED BY SOUTHERLY FLOW IN THE LOW LEVELS AS THE NORTHERN PLAINS SURFACE LOW TRACKS ALONG THE CANADIAN BORDER AND DRY WESTERLY MID LEVEL FLOW. THIS SHOULD GIVE THE REGION PLENTY OF SUN. KEPT TEMPERATURES IN THIS REGIME JUST ABOVE GUIDANCE IN THE SOUTH WHERE LITTLE SNOW COVER EXISTS WITH HIGHS IN THE LOW 40S. OVER THE SNOW COVERED NORTH WENT WITH HIGHS IN THE 30S. ..DLF.. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY... SUNDAY NIGHT AND MONDAY...LATEST SUITE OF 12Z RUN MODELS IN GENERALLY GOOD AGREEMENT THIS PERIOD OF SUGGESTING LEAD IMPULSE OF PACIFIC NW WAVE ENERGY/SEEN CURRENTLY ON WATER VAPOR IMAGERY ROTATING DOWN ALONG THE B.C. COAST/ TO RIDGE-RIDE NORTH OF THE U.S. BORDER ACRS SOUTHERN CANADA AND ACRS JAMES BAY INTO MON. ASSOCIATED SFC FRONT OFF THIS PASSING WAVE PROBABLY TO JUST MAKE IT ACRS THE FAR NORTHWESTERN CWA BY 12Z...THUS PRE-FRONTAL WAA AND SOME BOUNDARY LAYER MOISTURE INCREASE LATE AT NIGHT TO PRODUCE A STEADY TO SLOW TEMP RISE TOWARD DAWN AND LOWS WILL BE FROM MID EVENING THROUGH 3 AM CST. 50+ KT SOUTHWESTERLY LLJ TO REALLY WAA AND PRODUCE A WARM WEDGE/INVERSION ALOFT IN THE H85-H7 MB LAYER BY MONDAY. LIKE PREVIOUS SHIFT STATED...HIGHER DPTS ADVECTED IN AS WELL AS SOME SNOW MELT JUICED BL TRAPPED UNDER BUILDING INVERSION TO INDUCE LLVL STRATUS AND FOG LATE SUNDAY NIGHT INTO MON. STILL SOME QUESTION ON SPEED OF THIS DEVELOPING/MOISTURE INCREASE AND SOME RECENT SIGNALS OF THE LOW CLOUDS AND FOG REALLY DEVELOPING MORE CLOSER TO MONDAY MORNING AS OPPOSED TO SUNDAY NIGHT. BUT WILL KEEP FOG MENTION SUN NIGHT AND MONDAY. INCREASING LIFT AND MID LEVELS REMAINING DRY ALOFT SUGGEST DRIZZLE GETTING WRUNG OUT OF THIS LLVL CLOUD DECK...AND IF SFC TEMPS CAN/T CLIMB ABOVE FREEZING TIL DAWN MONDAY...MAY BE SOME TROUBLE WITH FREEZING DRIZZLE ALONG AND NORTH OF I-80 FRO AWHILE AND WILL MENTION IN THE ZONES. LOW CLOUDS AND LLVL SATURATION MAY LIMIT SFC HEATING ENOUGH TO KEEP TEMPS AT OR BELOW FREEZING UNTIL MID MON MORNING NORTH OF THE HWY 30 AREAS AND WILL EXTEND FREEZING DRIZZLE MENTION IN THESE AREAS FOR MON MORNING. FOG TO CONTINUE WELL INTO MON AS WELL. AS SFC BOUNDARY SAGS AND STALLS OUT ACRS THE CWA PARALLEL TO MEAN SOUTHWESTERLY STEERING FLOW ON MON...CONTINUED LLVL MOISTURE TRANSPORT AND CONVERGENCE INTO THIS FEATURE MAY INCREASE/SATURATE MOISTURE PROFILES DEEP ENOUGH FOR MORE OF A LIGHT RAIN FORMING ACRS MUCH OF THE SOUTHEAST TWO THIRDS OF THE DVN CWA BY LATE MORNING AND INTO THE AFTERNOON. THICK LLVL CLOUDS...FOG...SNOW MELT PROCESS...AND SATURATION MAY LIMIT SFC HEATING WITH HIGHS MORE IN THE MID TO UPPER 30S IN THE SOUTH HALF AS OPPOSED TO MODEL GUIDANCE UPPER 30S TO LOWER 40S. TEMPS MAY ACTUALLY HAVE TROUBLE WARMING ABOVE 32 IN THE FAR NORTHERN CWA/NORTH OF CID IA TO FREEPORT IL/ WHICH COULD EXTEND A FREEZING DRIZZLE OR VERY LIGHT FREEZING RAIN SCENARIO WELL INTO THE AFTERNOON IN THOSE AREAS. APPROACH OF MAIN UPPER TROF FROM THE PACIFIC NW AND ACRS THE PLAINS COULD INDUCE SOME LLVL WAVE DEVELOPMENT ALONG ON THE FRONT WHICH COULD EXTEND SOME PRECIP ALMOST DEF ZONE STYLE IN THE EASTERN CWA MONDAY EVENING. WITH TOP-DOWN COOLING AND SATURATION TAKING PLACE...THE RAIN COULD SWITCH OVER TO A MIX OR ALL SNOW WITHIN A FEW HOURS AFTER SUNSET WITH SOME LIGHT SLUSHY ACCUMULATION ALONG THE EASTERN I-80 CORRIDOR. TEMPS TO CRASH LATE MON NIGHT INTO TUE MORNING IN LLVL COLD CONVEYOR WITH VALUES RANGING FROM THE MID TEENS IN THE NORTHWEST...TO THE MID 20S IN THE FAR EAST AND SOUTHEAST. TUESDAY AND WEDNESDAY...THE LLVL CYCLONE REALLY TAKES OFF/DEEPENS ACRS THE CENTRAL GRT LKS ON TUE...BUT THE BRUNT OF THE PASSING UPPER TROF ACRS THE LOCAL AREA STILL TO PROBABLY TO MAKE FOR WIDESPREAD LIGHT SNOWS ACRS MOST OF THE DVN CWA THROUGH LATE TUE AFTERNOON BEFORE THE UPPER TROF AXIS PASSES ACRS LK MI BY TUE EVENING AND SUBSIDENCE TAKES OVER IN ITS WAKE. POTENTIAL FOR SOME 1-2 INCH AMOUNTS BY TUE EVENING MAINLY ALONG AND NORTH OF THE HWY 30 CORRIDOR...BUT MORE OF A STORY WILL BE THE COLD AND NORTHWESTERLY SFC WINDS GUSTING UP OVER 30 MPH AT TIMES WITH WIND CHILLS NEAR ZERO IN THE AFTERNOON. CLEARING AND COLD CONDITIONS TUE NIGHT WITH PASSING LLVL RIDGE LOBE...SOME LOWS BELOW ZERO POSSIBLE IN AREAS NORTH OF I80. PASSING CLIPPER ACRS MN/WI IN FRESHLY ESTABLISHED BROAD NORTH-WESTERLIES...MAY USHER YET ANOTHER FRONT INTO THE CWA BY LATE WED NIGHT WITH POSSIBLE FLURRIES. THURSDAY THROUGH SATURDAY...LLVL BAROCLINICITY TO GET ALIGNED PARALLEL UNDER THESE MEAN FLOW NORTH-WESTERLIES ACRS THE CWA ON THU...AND ANY PASSING WAVE ALOFT IN THE PROGRESSIVE FLOW COULD WRING OUT SOME LIGHT SNOW OR FLURRIES ALONG THE LLVL THERMAL RIBBON ON THU AND WILL CARRY LOW CHC POPS FOR THIS POTENTIAL. BOTH THE 12Z RUN GFS AND ECMWF NOW PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE WAVE PROPAGATING DOWN IN THIS FLOW ALONG THE BAROCLINICITY WHICH UTILIZES SOME GULF MOISTURE FEED FROM THE SOUTH TO PRODUCE 1-3 OR EVEN 2-4 INCHES OF SNOW ACRS THE NORTH HALF OF THE DVN CWA FROM LATE THU NIGHT INTO FRI MORNING. WILL KEEP CHC POPS GOING FOR SNOW ON FRI FOR NOW...AND MAYBE A MIX OF RAIN AND SNOW IN THE SOUTH WITH PRE- SYSTEM WARM DRAW ALOFT POSSIBLE. FLATTENING FLOW AND POST-SYSTEM RIDGING MAY BRING A LULL IN THE ACTION FOR LATER FRI NIGHT AND SAT. SOME SIGNS OF ENOUGH WAA ON SAT AHEAD OF TE NEXT DEVELOPING LARGE SYSTEM TO DRIVE TEMPS INTO THE MID TO UPPER 30S DEPENDING ON SNOW COVER BY THAT TIME. ..12.. && .AVIATION.../ISSUED 1158 AM CST SAT JAN 14 2012/ AN AREA OF LIGHT SNOW OR FLURRIES FROM WESTERN IA INTO EASTERN MN WILL MOVE EAST ACROSS THIS AFTERNOON AND THIS EVENING. MVFR CIGS/ VSBYS WILL BE ASSOCIATED WITH THE SNOW AT KCID/KDBQ/KMLI LATE THIS AFTERNOON AND THIS EVENING WITH MAINLY VFR CIGS/VSBYS AT KBRL. CIGS/VSBYS TO IMPROVE TO VFR BY LATE EVENING OR EARLY SUNDAY MORNING. LIGHT SOUTHERLY WINDS THIS AFTERNOON THROUGH LATE TONIGHT WILL BE INCREASING TO AROUND 10KTS SUNDAY MORNING. ..DLF.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ DLF/12
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 AM CST SAT JAN 14 2012 ...UPDATE TO AVIATION... .DISCUSSION... SHORT RANGE (TODAY AND SUNDAY)... 09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST- NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY. MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)... THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH- SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS THAT DAY APPROACHES. JL .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && .AVIATION... VFR CONDITIONS EXPECTED FOR THE NEXT 24 HRS. WINDS WILL REMAIN GUSTY UNTIL 20-21Z. WINDS WILL BECOME WESTERLY AND SOUTHWESTERLY LATER THIS AFTERNOON AND OVERNIGHT AS SURFACE HIGH PRESSURE MOVES TO THE SOUTHEAST. PRESSURE GRADIENT TIGHTENS AGAIN TOMORROW AND SOUTHERLY WINDS WILL BECOME GUSTY AFTER 15Z. ANDERSON && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
210 PM CST SAT JAN 14 2012 .DISCUSSION... NEED TO DO A QUICK UPDATE FOR TEMPS THIS AFTN AS TEMPS RISING WELL INTO THE MID 30S IN FAR SE ND... THIS IS HIGHER THAN PREV UDPATE.... && .PREV DISCUSSION... /ISSUED 1002 AM CST SAT JAN 14 2012/ DISCUSSION... MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID 20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA. ,AVIATION... CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW. PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/ DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL USE BLEND. BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY. FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN THE 20S. TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE. NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED 32 DEGREES. STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY TO RECOVER AT ALL MONDAY AND MAY EVEN DROP. LONG TERM (TUE-FRI)... MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
352 PM EST SAT JAN 14 2012 .SYNOPSIS... A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS TO DEVELOP THIS EVENING. BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND LESSER AMOUNTS OVER SRN COALFIELDS. WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS OVER THE MOUNTAINS. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... QUIET START TO THE PERIOD WITH HIGH PRESSURE TRUDGING EAST SUNDAY NIGHT. SOUTHWESTERLY FLOW KICKS IN WITH H925 WINDS INCREASING TO 30-40 KNOTS BY 12Z. THIS FLOW WILL START TO PUSH SOME HIGH CLOUDS IN TOWARDS MORNING...OTHERWISE SKIES WILL BE MOSTLY CLEAR. THE WINDS WILL ALSO BE PUSHING IN WARMER AIR ALOFT...H925 TEMPERATURES RISE FROM -6C AT 00Z TO +6 AT 12Z. MODELS STILL HAVE A SHARP INVERSION NEAR THE SURFACE THROUGH THE NIGHT. STILL...WITH SUCH STRONG WINDS ALOFT...THINK SOME OF THE WARMER AIR WILL MIX DOWN AND ALLOW FOR RISING TEMPERATURES OVERNIGHT. SO...WENT WITH A MIN TEMP CLOSE TO THE MET AROUND MIDNIGHT...WITH A NONDIURNAL RISE THEREAFTER. ECMWF DOES LOOK LIKE A GOOD MIDDLE-OF-THE-ROAD APPROACH TO NEXT SYSTEM...WITH A GENERALLY LARGE MODEL SPREAD. LOW PRESSURE DEVELOPS IN THE PLAINS ON MONDAY...AND THEN TAKES OFF TO THE NORTHEAST TOWARDS YYZ BY 00Z WEDNESDAY. SUPPORT WILL BE PROVIDED BY DEEPENING SHORTWAVE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. SOME ISENTROPIC LIFT NOTED ON MONDAY...MUCH OF WHICH WILL GO INTO MOISTENING THE ATMOSPHERE AT FIRST AND INCREASING CLOUD COVER. SUFFICIENTLY DEEP MOISTURE ARRIVES BY 18Z AND ALLOWS THE FIRST RAINDROPS IN SOUTHEAST OHIO. PWAT CONTINUES TO INCREASE IN THE SOUTHWEST FLOW...EVENTUALLY REACHING AN INCH OR SO BY 12Z TUESDAY. POPS CONTINUE TO TREND UPWARD...REACHING THEIR PEAK BY 12Z TUESDAY WITH CATEGORICAL VALUES ACROSS MUCH OF THE AREA. SUPPORT FOR LIFT WILL BE PROVIDED BY LFQ OF H250 JET ALONG WITH CONTINUED 290/295K ISENTROPIC UPGLIDE. STILL...RAIN RATES SHOULD NOT BE EXCESSIVE...AND AROUND A HALF INCH OF RAIN CAN BE EXPECTED FROM THIS EVENT THROUGH 12Z TUESDAY. RAN CLOSER TO MET NUMBERS MONDAY/MONDAY NIGHT...WHICH HAD A SMALLER DIURNAL RANGE THAN THE MAV. THEREAFTER...WE AWAIT COLD FROPA WHICH WILL OCCUR LATER TUESDAY AFTERNOON AND TUESDAY EVENING. ANOTHER .20 TO .30 INCH OF RAIN IS POSSIBLE IN CONTINUED MOIST FLOW/LIFT. UNCERTAINTY WITH TIMING LEADS TO UNCERTAINTY IN CHANGEOVER TO SNOW...BUT FOR NOW THINK THIS OCCURS AFTER 00Z WEDNESDAY. BY THAT TIME...DEEPER MOISTURE IS DEPARTING AND ONLY HAVE LIKELY POPS ALONG WESTERN SLOPES...WITH WINDS BEGINNING THE TRANSITION TO WESTERLY AND EVENTUALLY NORTHWEST. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR CONDITIONS IN PERIODS OF HEAVIER SNOW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT. THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST IN THE WESTERN LOWLANDS. 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 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H M M M M M M M M M M HTS CONSISTENCY H H H M M M M M M H H H BKW CONSISTENCY H H H M M M M M M M M M EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY M M L L M M H H H H H H CKB CONSISTENCY M M M M M M M M M M M M AFTER 18Z SUNDAY... IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004. && $$ SYNOPSIS...KMC/JB/CL NEAR TERM...KMC SHORT TERM...CL LONG TERM...JB AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
235 PM EST SAT JAN 14 2012 .SYNOPSIS... A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS TO DEVELOP THIS EVENING. BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND LESSER AMOUNTS OVER SRN COALFIELDS. WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS OVER THE MOUNTAINS. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S. LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO 1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF FZRA MONDAY NIGHT. IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A RESULT. COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT. THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO HELP TO LIMIT ACCUMULATIONS SOMEWHAT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR CONDITIONS IN PERIODS OF HEAVIER SNOW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT. THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST IN THE WESTERN LOWLANDS. 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 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H M M M M M M M M M M HTS CONSISTENCY H H H M M M M M M H H H BKW CONSISTENCY H H H M M M M M M M M M EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY M M L L M M H H H H H H CKB CONSISTENCY M M M M M M M M M M M M AFTER 18Z SUNDAY... IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004. && $$ SYNOPSIS...KMC/JB/CL NEAR TERM...KMC SHORT TERM...SL LONG TERM...JB AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
217 PM EST SAT JAN 14 2012 .SYNOPSIS... A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS TO DEVELOP THIS EVENING. BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND LESSER AMOUNTS OVER SRN COALFIELDS. WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS OVER THE MOUNTAINS. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S. LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO 1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF FZRA MONDAY NIGHT. IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A RESULT. COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT. THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO HELP TO LIMIT ACCUMULATIONS SOMEWHAT. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... GENERALLY USED ECMWF MEAN FOR THE PERIOD. A RAIN SYSTEM MOVES INTO THE REGION MONDAY NIGHT AND TUESDAY...FOLLOWED BY ANOTHER COLD SNAP TUESDAY NIGHT AND WEDNESDAY. COULD SEE SOME UPSLOPE SNOW ACCUMULATIONS TUESDAY NIGHT AND WEDNESDAY WITH THE COLD AIR. FORECAST GETS MUCH LOWER CONFIDENCE FOR THE END OF THE WORK WEEK AS OPERATIONAL MODELS DIVERGE CONSIDERABLY. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR CONDITIONS IN PERIODS OF HEAVIER SNOW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT. THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST IN THE WESTERN LOWLANDS. 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 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H M M M M M M M M M M HTS CONSISTENCY H H H M M M M M M H H H BKW CONSISTENCY H H H M M M M M M M M M EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY M M L L M M H H H H H H CKB CONSISTENCY M M M M M M M M M M M M AFTER 18Z SUNDAY... IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004. && $$ SYNOPSIS...KMC/JB/CL NEAR TERM...KMC SHORT TERM...SL LONG TERM...RPY AVIATION...KMC
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
320 PM EST SAT JAN 14 2012 .SYNOPSIS... A CLIPPER AREA OF LOW PRESSURE ARRIVES FROM THE NORTHWEST TONIGHT INTO EARLY SUNDAY...BRINGING ANOTHER ROUND OF MOUNTAIN SNOW SHOWERS. HIGH PRESSURE WILL BUILD ACROSS THE AREA SUNDAY AND OFFSHORE INTO MONDAY PROVIDING A GRADUAL MODERATION IN TEMPERATURES FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH SUNDAY/... AS OF 230 PM EST SATURDAY... ISSUED A WSW FOR SOUTHWEST PORTIONS OF CWA TONIGHT INTO SUNDAY MORNING FOR LIGHT SNOW EVENT ASSOCIATED WITH A FAST MOVING CLIPPER. LEANING TOWARDS BLEND OF THE SREF AND NAM BELIEVE THERE IS ENOUGH LOW LEVEL MOISTURE WITH SHORTWAVE TO PRODUCE 1 TO 3 INCHES OF SNOW ACROSS THE HIGHER TERRAIN WITH A BURST OF SNOW ALONG THE WESTERN SLOPES...ESPECIALLY IN THE NW NC MOUNTAINS WHERE UVV IS FORECAST TO BE THE GREATEST. WITH LOCAL WRFARW-RNK AND HRRR EVEN SHOWING MOISTURE SPREADING FURTHER EAST...DECIDED TO EXPAND AND INCREASE CHANCES INTO THE MOUNTAINS AND ALLOW FOR SNOW FLURRIES TO SPILL EAST INTO THE FOOTHILLS. PLAYED LOW TEMPERATURES TONIGHT CLOSE TO THE ADJMAV WITH READINGS FROM AROUND 10 DEGREES WITH SNOWPACK IN THE NORTHWEST MOUNTAINS TO THE MID 20S IN THE SOUTHEAST. SNOW SHOWERS AND SNOW FLURRIES WILL END QUICKLY SUNDAY...WITH UPPER RIDGE AND SFC HIGH BUILDING OVER THE REGION. WENT WITH HIGHS ON SUNDAY FROM THE MID 20S IN THE NORTHWEST TO THE LOWER 40S IN THE SOUTHEAST. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 300 PM EST SATURDAY... CHALLENGING PORTION OF THE FORECAST. HIGH PRESSURE ALTHOUGH LEAVING SE WEST VA LATE SUNDAY NIGHT...SHOULD ALLOW DECOUPLING AND TEMPS TO FALL NEAR DEWPOINT LEVELS. THIS WOULD PUT MOST SPOTS AT OR BELOW GUIDANCE...ESPECIALLY THE SOUTHSIDE AND PIEDMONT WHERE HIGH PRESSURE IS CENTERED AT 1Z/7A MONDAY. LAST FRAME OF RGEM SIMULATED SAT IMAGES SHOWS AT LEAST THICK HIGH CLOUDS JUST THEN ENTERING THE SW QUARTER OF OUR CWA ALSO AT THAT TIME...WITH A LATE SSW TO SW WIND DEVELOPING LATE SUNDAY NIGHT. THUS...TEMPS MAY RISE LATE SUNDAY NIGHT ACROSS NW NC AND EXTREME SW VA AFTER DECOUPLING EARLIER IN THE EVENING...BUT WILL NOT TRY TO PUT THIS DETAIL IN THE HOURLY T GRIDS FOR NOW. WITH THE CLOUDS THICKENING IN THE WEST MONDAY MORNING...AND THEN MOVING EAST BY LATE DAY...TEMPS MAY HAVE A HARD TIME WARMING TO GUIDANCE NUMBERS WITH MOSTLY CLOUDY SKIES AND A STEEP INVERSION IN PLACE WITH H85 TEMPS UNLIKELY TO MIX TO THE SURFACE. CONSIDERING THIS REGIME...MONDAY NIGHT`S FORECAST BECOMES ALL THE MORE DIFFICULT...WITH TEMPS WARM ENOUGH ALOFT FOR RAIN...BUT RATHER LARGE DEWPOINT DEPRESSION AND POSSIBLY SOME BROKEN CLOUD COVER...TEMPS COULD FALL FAST IN THE SHELTERED VALLEYS WEST OF THE BLUE RIDGE...FOR SOME POSSIBLE FREEZING RAIN...BEFORE TEMPS WARM AFTER MIDNIGHT TO ABV FREEZING. DID HAVE TO PUT IN HOURLY T GRIDS FOR THIS PERIOD...AS LESS CLOUDS IN THE EXTREME EAST MAY ALLOW THOSE PARTS TO DECOUPLE AGAIN...WHEREAS TEMPS FALL INITIALLY IN SE WEST VA THEN RISE SLIGHTLY AFTER MIDNIGHT. GROUND ALSO WILL BE RATHER COOL CONSIDERING FEW DAY STRING OF MORE WINTERLIKE TEMPS INCLUDING LOWS IN THE MID AND UPPER TEENS SUNDAY NIGHT. FOR NOW...COMBINED A SLT CHC OF FREEZING RAIN FOR A FEW HOURS WITH REGULAR RAIN TO HIGHLIGHT THIS THREAT. H85 TEMPS THEN AT 12Z/7A TUESDAY SITTING AROUND +6C SHOULD EVEN WITH THE RAIN AROUND ALLOW TEMPS TO PUSH 60F EAST OF THE BLUE RIDGE AND MAYBE EVEN ROANOKE TOO...WITH A DOWNSLOPING WIND AND WARM SURGE AHEAD OF THE NEXT POTENT BAROCLINIC BOUNDARY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 300 PM EST SATURDAY... A COLD FRONT WILL ROLL ACROSS THE REGION TUESDAY EVENING WITH RAIN SHOWERS ENDING AROUND MIDNIGHT. VERY COLD AIR AND A TIGHT PRESSURE GRADIENT WILL THEN BRING WINDY AND GUSTY CONDITIONS TO THE AREA...ALONG WITH WESTERN UPSLOPE SNOW SHOWERS INTO WEDNESDAY MORNING. THE WIND AND SNOW WILL BE BRIEF AS HIGH PRESSURE BUILDS INTO THE REGION WEDNESDAY AFTERNOON. HIGH PRESSURE DRIFTS OFF THE EAST COAST...WHILE A DISTURBANCE TRACKS OVER THE NORTHERN OHIO VALLEY THURSDAY. THIS DISTURBANCE IS FAR ENOUGH AWAY FROM THE AREA TO KEEP POPS LOW AND CONFIDED TO THE GREENBRIER VALLEY/ALLEGHANY HIGHLANDS THURSDAY EVENING. ANOTHER DISTURBANCE IS EXPECTED TO TRACK ACROSS THE OHIO VALLEY FRIDAY NIGHT AND SATURDAY. THIS DISTURBANCE HAS PACIFIC ORIGIN AND WILL BE WARM WHEN IT ENTERS THE REGION. COLD TEMPERATURES WILL HANG AROUND TUESDAY NIGHT INTO WEDNESDAY NIGHT. AS THE CHILLY HIGH PRESSURE SYSTEM MOVES OFF THE COAST AND ZONAL FLOW IS ESTABLISHED ON THURSDAY...TEMPERATURES WILL MODERATE ABOVE NORMAL FRIDAY AND SATURDAY. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... AS OF 1134 AM EST SATURDAY... SCT TO BKN MVFR CLOUDS IN THE WESTERN MOUNTAINS THIS AFTERNOON. OTHERWISE...VFR CONDITION EXPECTED. GUSTY NORTHWEST WINDS ACROSS THE HIGHER TERRAIN MAY HINDER AVIATION OPERATIONS. A LAYER OF CLOUDS AROUND 5K FEET WILL SPREAD EAST ACROSS CWA LATE THIS AFTERNOON AND EARLY THIS EVENING AT ALL TAF SITES. A UPPER LEVEL DISTURBANCE WILL MOVE THROUGH OUR AREA TONIGHT BRINGING A REINFORCEMENT OF COLD AIR AND SNOW SHOWERS TO KBLF AND KLWB. SNOW OR SNOW FLURRIES MAY EVEN PUSH INTO KBCB/KROA LATE TONIGHT INTO SUNDAY MORNING. MVFR CIGS WILL RETURN FOR KBLF AND KLWB INTO SUNDAY. SHOULD SEE ALL SITES RETURN TO VFR UNDER HIGH PRESSURE ON MONDAY WITH ANOTHER FRONT BRINGING ADDED CHANCES OF RAIN AND LOW CIGS BY TUESDAY. WITH COLDER AIR COMING IN WEDNESDAY...MOUNTAINS SNOW SHOWERS AND SNOW FLURRIES ARE POSSIBLE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR VAZ007-009- 015. NC...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR NCZ001-018. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...KK/PH SHORT TERM...KM LONG TERM...RCS AVIATION...KK/PH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
246 PM CST SAT JAN 14 2012 .SHORT TERM...TONIGHT AND SUNDAY. THE SURFACE PRESSURE PATTERN OVER THE REGION WAS CAUSING SOME ISSUES IN THE SHORT TERM. 20Z ANALYSIS SHOWED WEAK LOW PRESSURE OVER LAKE MICHIGAN...A WEAK RIDGE OVER WISCONSIN AND A TROUGH ACROSS MINNESOTA. CONVERGENCE OVER THE LAKE RESULTED IN A BAND OF LAKE EFFECT SNOW SHOWERS THAT PUSHED WEST INTO DOOR COUNTY. THE 15Z RUC APPEARED TO HAVE A DECENT HANDLE ON THE SITUATION AS IT WAS SHOWING QPF IN THE EASTERN PART OF THE FORECAST AREA INTO THIS EVENING. WENT WITH SOME POPS IN THE EAST FOR THE EVENING BUT DRY THERE AFTER 06Z. NOT REALLY SURE WHAT WAS CAUSING THE LIGHT SNOW AND FLURRIES IN CENTRAL WISCONSIN TODAY DIRECTLY UNDER THE SURFACE RIDGE...POSSIBLY SOME WEAK SHORT WAVE ENERGY PASSING THROUGH THE STATE. THE VISIBILITY IN SOME LOCATIONS WENT AS LOW AS 3 MILES WITH SNOW AT TIMES. ANOTHER AREA OF LIGHT SNOW...WITH VISIBILITIES BELOW 2 MILES...WAS ASSOCIATED WITH A WARM FRONT ACROSS MINNESOTA...AND A SHEARED UPPER LEVEL SHORT WAVE. MODELS HAD THE FRONT DECAYING...THE SHORT WAVE ENERGY MOVING SOUTHEAST THIS EVENING AND HAD QPF DRYING UP BEFORE REACHING THE FORECAST AREA. HAVE SOME SLIGHT CHANCE POPS FOR CENTRAL WISCONSIN DURING THE EVENING...BUT NOTHING AFTER 06Z. TIME/HEIGHT SECTIONS FROM MODELS HAD QUITE A BIT OF LOW LEVEL MOISTURE WITH LITTLE LIFT LATE TONIGHT...MAINLY IN THE NORTH. SO HAVE INCLUDED A SLIGHT CHANCE OF FREEZING DRIZZLE OR FLURRIES THERE 06Z-12Z SUNDAY. PLENTY OF CLOUDS TONIGHT...BUT THINK THAT TEMPERATURES SHOULD FALL INTO THE SINGLE DIGITS IN MOST LOCATIONS. WARMER THAN NORMAL HIGHS RETURN ON SUNDAY IN STRONG WARM ADVECTION AHEAD OF THE SURFACE SYSTEM APPROACHING FROM THE WEST. MODELS STILL HAD PLENTY OF CLOUDS SO DID NOT GO TOO MUCH ABOVE GUIDANCE HIGHS. EXPECT WINDS TO STEADILY INCREASE DURING THE DAY ON SUNDAY AHEAD OF THE APPROACHING SYSTEM. .LONG TERM...MONDAY THROUGH NEXT SATURDAY. NOT MUCH CHANGE TO THE IDEA OF DEVELOPMENT OF HIGH AMPLITUDE RIDGING OVER THE BERING STRAIT WITH NRN STREAM ENERGY DIGGING SE THRU ALASKA/WRN CANADA. THIS RESULTS IN DEVELOPING BROAD UPPER TROF ACROSS SRN CANADA/NRN CONUS. THE MEAN FLOW UNDER THIS TROF TO BE NEAR ZONAL FROM THE US...BRINGING SEVERAL RELATIVELY WEAK SYSTEMS ACROSS THE WRN GREAT LAKES. AT BEGINNING OF PERIOD...LOW PRESSURE MOVES EAST INTO CNTRL ONTARIO SUNDAY NGT AND DRAGS COLD FRONT INTO CNTRL WI BY 12Z MONDAY. IT STILL APPEARS THAT GULF MOISTURE WILL NOT HAVE TIME TO REACH THE FORECAST AREA PRIOR TO THE FRONTAL PASSAGE. FRONT EXISTS REGION BY EARLY IN THE AFTERNOON...THEN SHORT WAVE TROF APPROACHES FROM THE W. SNOW SHOULD DEVELOP ALONG TIGHT BAROCLINIC ZONE ACROSS THE AREA BY EARLY TUESDAY. ALL MODELS IN GENERAL AGREEMENT WITH DEVELOPMENT OF SFC WAVE ALONG THE FRONT. ACCUMULATIONS SHOULD BE GENERALLY MINOR...LESS THAN 2 INCHES THRU TUE. SOME LAKE EFFECT LINGERS IN LAKE SUPERIOR SNOW BELT OF FORECAST AREA INTO TUE NIGHT. MIDWEEK TEMPS WILL BE BELOW NORM AS ARCTIC AIR BRIEFLY FINDS A HOME. SMALL CHANCES FOR SNOW SHOWERS ACROSS AREA AS WEAK RIPPLES IN WNW UPPER FLOW CONTINUE TO MOVE ALONG BAROCLINIC ZONE. BOTH THE 14/12Z GFS AND ECMWF TARGET FRIDAY AS THE BEST SNOW CHANCE IN THE SECOND HALF OF THE WEEK WITH SHORT WAVE TROF MOVING ACROSS MIDWEST AND SURFACE LOW MOVING ACROSS S ILLINOIS. && .AVIATION...QUITE A BIT OF UNCERTAINTY EXISTS DURING THE TAF PERIOD. CURRENT TRENDS WERE CHALLENGING ENOUGH. CIGS WERE MAINLY MVFR NORTH AND WEST OF THE FOX VALLEY AND VFR OVER THE REST OF THE AREA. THERE WERE ALSO SCATTERED MVFR VSBYS IN LIGHT SNOW AND/OR HAZE. A LAKE EFFECT BAND OVER LAKE MICHIGAN WAS DRIFTING TOWARD WISCONSIN AS A TROUGH/FRONT APPROACHED THE STATE FROM THE WEST. THINK THERE WILL BE SOME LIGHT SNOW OR FLURRIES GOING ON MUCH OF THE NIGHT WITH MOSTLY MVFR CIGS AS THE SURFACE BOUNDARY APPROACHES FROM THE WEST. TIME/HEIGHT SECTIONS INDICATED A DECREASE IN LOW LEVEL MOISTURE AFTER ABOUT 15Z SUNDAY WITH SOME MID CLOUDS ABOVE THAT. PAY EXTRA ATTENTION TO CURRENT CONDITIONS AND WATCH FOR TAF UPDATES IF YOU PLAN TO FLY IN THE AREA THIS AFTERNOON THROUGH SUNDAY MORNING. MG && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MG/JKL
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1205 PM CST SAT JAN 14 2012 .UPDATE...FLURRIES OVER THE EASTERN CWA DIMINISHING AS DRIER MID LEVEL AIR ADVECTS IN. CLOUD COVER THINNER AND MORE SCATTERED THAN PREVIOUSLY EXPECTED...BUT ENOUGH SNOW COVER IS PRESENT THAT SUNSHINE HAS NOT HAD A BIG IMPACT ON TEMPS. BUMPED HIGHS DOWN SLIGHTLY. BIGGEST CHANGE TO AFTERNOON PERIOD WILL BE POPS. ISENTROPIC ANALYSIS NO LONGER SHOWS NECESSARY INGREDIENTS FOR PRECIP FORMATION. THIS IS BACKED UP BY LATEST 3KM HRRR OUTPUT. WILL BACK OFF TO SLIGHT CHANCE...KEEPING IT IN THE WEST. && .AVIATION/18Z TAFS/...FLURRIES STILL LINGERING FROM MADISON AND EASTWARD. SHOULD SEE FLURRIES DIMINISH THROUGH THE AFTERNOON AS THE LOW LEVELS DRY OUT. SKIES ARE MAINLY VFR NOW ACROSS SRN WI...BUT COULD STILL SEE A FEW SPOTS OF BRIEF MVFR CIGS AS THINGS SLOWLY DRY OUT. WEAK WAVE TO SLIDE THROUGH THIS EVENING...BUT LOOKING EVEN WEAKER AND DRIER WITH LATEST MODELS. THOUGH FLURRIES MAY BE POSSIBLE FROM AROUND MADISON AND SOUTHWEST...CHANCES LOOK LOW ENOUGH TO REMOVE FROM MSN TAFS. MODELS SATURATE THE LOW LEVELS FOR A TIME BEHIND THE WAVE LATE TONIGHT INTO SUNDAY MORNING...SO PUT SOME MVFR CIGS IN THE TAFS. && .PREV DISCUSSION... /ISSUED 341 AM CST SAT JAN 14 2012/ TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM. BACK EDGE OF LOW CLOUDS HAVE BEEN MOVING STEADILY EWD AT 12KTS SINCE FRI EVE...HOWEVER HAVE NOTICED SLIGHT SLOWING OF PROGRESSION EWD SINCE 07Z. LOW LEVEL CYCLONIC CURVATURE AND BULK OF CLOUDS IN DENDRITIC GROWTH ZONE BELOW INVERSION WL CONTINUE TO SHAKE OUT SOME FLURRIES THIS MRNG...ESPECIALLY IN THE SOUTHEAST. SLIGHTLY DRIER AIR SETTLING IN FROM THE NORTHEAST WL HELP TO END THE FLURRIES MOST AREAS. LOW LEVEL THERMAL TROUGH LINGERS ACROSS EASTERN WI THRU MID-AFTN... SO EXPC LOW CLOUDS TO HANG ON INTO THE AFTN. UPSTREAM SHORT WAVE AND ASSOCIATED SWIRL SHOWS UP CLEARLY ON WATER VAPOR IMAGERY OVR ERN SASK PUSHING INTO SW MANITOBA. SHORT TERM GUIDANCE IN GOOD AGREEMENT ON CARRYING THIS WAVE SOUTHEAST AND ACROSS SW WI THIS EVE. EXPC WAVE TO WEAKEN AS IT MOVES ACROSS OUR REGION DUE TO UPSTREAM SUBSIDENCE SPREADING RAPIDLY EWD INTO THE NRN PLAINS AND UPPER MIDWEST...AHEAD OF NEXT STRONGER WAVE PUSHING THRU SW CANADA. CONDENSATION PRESSURE DEFICITS ON 280 THETA SFC LOWER TO LESS THAN 10MB WITH WEAK ISENTROPIC UPGLIDE BY LATE AFTN OVER WRN CWA. WL INCREASE TO LKLY WORDING IN FAR WEST BY LATE AFTN. AREA OF LOWER CPD AFFECTS REST OF SOUTH CENTRAL WI THRU THE EARLY EVE...HOWEVER WEAK FORCING CONTINUES TO DIMINISH. THINK THERE WILL BE AREAS OF VERY LIGHT SNOW AROUND SOUTH CENTRAL...AND PARTS OF SOUTHEAST IN THE EVE...BUT MANY LOCATIONS WL NOT RECEIVE MEASURABLE QPF. HENCE WL KEEP POPS ON THE LOW SIDE...AND NEXT SHIFT WL BE ABLE TO TWEAK. WHILE WEAK FORCING LINGERS OVER SOUTH CENTRAL WI DURING THE LATE EVENING...MID LEVELS DRY OUT. HENCE VERY SMALL THREAT OF PATCHY FREEZING DRIZZLE FOR A FEW HOURS. CLOUDS EXPCD TO HANG ON THRU LATE TNGT IN WEAK FLOW. SHORT TERM...SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM. WARM AIR ADVECTION CONTINUES ON SUNDAY ACROSS THE AREA. SURFACE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA...WHICH SHOULD ALLOW FOR BREEZY SOUTH SOUTHEAST WINDS. SKIES SHOULD GRADUALLY SCATTER OUT AS THE DAY GOES ON...WHICH SHOULD ALLOW TEMPERATURES TO RISE INTO THE LOWER TO PERHAPS MID 30S. AREA REMAINS IN WARM SECTOR SUNDAY NIGHT...AS COLD FRONT APPROACHES FROM THE NORTHWEST. NAM CONTINUES TO BE ONLY SHORT TERM MODEL TO PRODUCE VERY LIGHT QPF WITH THE FRONT SUNDAY NIGHT. AREA FORECAST SOUNDINGS FROM NAM ARE QUITE DRY EXCEPT THE BOUNDARY LAYER DURING THIS TIME...WITH THE GFS SIMILAR. THUS...WILL CONTINUE DRY FORECAST SUNDAY NIGHT. TEMPERATURES WILL REMAIN MILD WITH SOUTH WINDS AHEAD OF THE FRONT. COLD FRONT SLIDES SOUTHEAST THROUGH THE FORECAST AREA ON MONDAY. NAM CONTINUES TO SHOW VERY LIGHT QPF IN THE MORNING...WITH THE OTHER SHORT TERM MODELS DRY IN THE MORNING. NAM/CANADIAN/ECMWF THEN SHOW LIGHT QPF IN THE FAR SOUTHEAST COUNTIES MONDAY AFTERNOON...WITH THIS AREA ON NORTHERN PERIPHERY OF LOW LEVEL FRONTOGENESIS BAND. AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING AIR COLUMN HAVING A TOUGH TIME SATURATING...MAINLY IN THE 850MB TO 500MB LAYER. FOR NOW...WILL MAINTAIN CHANCE POPS FOR MONDAY. TEMPERATURES WOULD SUPPORT LIGHT SNOW IN THE MORNING...AND A MIX IN THE AFTERNOON IN THE SOUTHEAST AS TEMPERATURES WARM. NAM/GFS/CANADIAN MODELS ARE TAKING SURFACE LOW FROM CENTRAL/WEST CENTRAL MISSOURI TO SOUTHEAST LOWER MICHIGAN/NORTHWEST OHIO MONDAY NIGHT...WITH THE ECMWF SLOWER AND ONLY IN NORTHERN INDIANA BY 12Z TUESDAY. 850MB BAROCLINIC ZONE AND LOW LEVEL FRONTOGENESIS RESPONSE SHIFT SOUTHEAST THROUGH THE AREA MONDAY EVENING...THEN SOUTHEAST OF THE AREA LATER MONDAY NIGHT. THEY ALSO BRING DIFFERENTIAL CYCLONIC VORTICITY ADVECTION INTO THE AREA MONDAY NIGHT. THE ECMWF KEEPS THE 850MB BAROCLINIC ZONE OVER THE AREA THROUGH THE NIGHT...WITH THE SHORTWAVE TROUGH STILL WEST OF THE REGION. WILL FOLLOW THE NAM/GFS/CANADIAN TRENDS AND KEEP LIKELY POPS GOING IN THE SOUTHEAST CORNER OF THE AREA...WITH CHANCE POPS ELSEWHERE. GFS/ECMWF CONTINUE TO DIFFER ON TUESDAY...WITH THE ECMWF BRINGING A MORE AMPLIFIED SHORTWAVE TROUGH THROUGH THE REGION. THIS HELPS CYCLOGENESIS WITH THE DOWNSTREAM SURFACE LOW. THE GFS IS LESS AMPLIFIED BUT STILL BRINGS THIS FEATURE THROUGH THE AREA. GFS ALSO SHOWING MID LEVEL FRONTOGENESIS BAND STAYING WEST AND NORTH OF THE AREA. STILL...BOTH MODELS SHOWING LIGHT QPF OF UP TO 0.15 INCHES ON THE ECMWF ON TUESDAY. WILL CONTINUE LIKELY POPS FOR LIGHT SNOW. AT THIS TIME...IT APPEARS THAT SNOW ACCUMULATIONS WOULD BE ON THE LIGHTER SIDE THAN PREVIOUSLY THOUGHT. STILL...THIS SYSTEM NEEDS TO BE WATCHED IN CASE IT SLOWS DOWN AND AMPLIFIES. BRISK NORTHWEST WINDS WILL BRING COLDER AIR INTO THE AREA...AND WOULD HELP BLOW AND DRIFT ANY NEW FALLEN SNOW. STAY TUNED. LONG TERM...TUESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE LOW TO MEDIUM. WEAK HIGH PRESSURE RIDGE TUESDAY NIGHT BRINGS QUIET WEATHER...BEFORE ECMWF/GFS SHOW DIFFERENCES WITH WEAKER SYSTEMS FOR THE REST OF THE WEEK. THEY BRING ALBERTA CLIPPER SYSTEM SOUTHEAST THROUGH THE REGION LATER WEDNESDAY INTO WEDNESDAY NIGHT...GFS QUICKER THAN THE ECMWF. THESE MODELS THEN DIFFER QUITE A BIT WITH FEATURES LATER IN THE WEEK. FOR NOW...WILL GO WITH CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD GIVEN THE FAIR AMOUNT OF UNCERTAINTY FROM THE MODELS. AVIATION/12Z TAFS/...BACK EDGE OF MVFR CEILINGS OVER SW WI HAS BEEN MOVING STEADILY EWD AROUND 12KTS...BUT HAVE NOTICED A SLIGHT SLOWING IN LAST SEVERAL 11-3.9 MICRON IMAGES SINCE 08Z. WEAK CYCLONIC CURVATURE AND BULK OF LOW LEVEL MOISTURE IN DENDRITIC GROWTH ZONE WL CONTINUE TO SHAKE OUT FEW FLURRIES THIS MRNG ESPECIALLY IN SOUTHEAST AS SLIGHTLY DRIER AIR SETTLES IN FROM THE NORTH. WL GRADUALLY RAISE CEILINGS IN EAST TO VFR BUT LOW CLOUDS COULD VERY WELL HANG ON ALL DAY AS LOW LEVEL THERMAL TROUGH WL BE SLOW TO MOVE OFF TO THE EAST. WL HOLD ONTO LOW VFR CIGS IN EAST WITH A SMALL THREAT FOR VERY LIGHT SNOW THIS EVE AS WEAKENING SHORT WAVE SLIDES THRU THE REGION. WL TAKE CIGS AND VSBYS BRIEFLY DOWN IN KMSN AS SOUTH CENTRAL WI WL BE CLOSER TO DEEPER MOISTURE AND BETTER WEAK LIFT. MARINE...QUIET CONDITIONS EXPCD IN THE SHORT TERM AS WEAK HIGH PRESSURE LINGERS OVER LAKE MI INTO TNGT. STRENGTHENING LOW PRESSURE IS EXPECTED TO MOVE THROUGH SRN CANADA ON SUN AND MON RESULTING IN A TIGHTENING PRESSURE GRADIENT OVER THE WRN GTLAKES. THE LOW WILL PULL A COLD FRONT THROUGH THE AREA ON MONDAY RESULTING IN BRISK SW WINDS TURNING TO THE N-NW. WIND SPEEDS WL LIKELY REACH SMALL CRAFT LEVELS DURING THIS PD. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...WIMBERLEY/DDV TODAY/TONIGHT AND AVIATION/MARINE...MBK SUNDAY THROUGH FRIDAY...WOOD