Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/27/13


AREA FORECAST DISCUSSION
NWS PUEBLO CO
133 AM MST MON NOV 25 2013 .UPDATE... ISSUED AT 129 AM MST MON NOV 25 2013 ISSUED WINTER WEATHER ADVISORY FOR SOUTHERN I-25 CORRIDOR AS BAND OF VERY HEAVY SNOW CONTINUES ALONG AND JUST WEST OF THE INTERSTATE. HAD HOPED ONSET OF NORTH WINDS WOULD BOOST TEMPS ABOVE FREEZING AND LIMIT ACCUMS...BUT LATEST OBS HAVE FALLEN BACK SLIGHTLY AS HEAVIER PRECIP DRIVES TEMPS DOWNWARD. HAVE ALREADY RECEIVED REPORTS OF 6 INCHES AROUND WALSENBURG. OTHER CHANGE TO FORECAST WAS TO EXTEND ADVISORY UNTIL 16Z FOR THE WETS AND SOUTHERN SANGRES AS SNOWFALL WILL BE SLIGHTLY SLOWER TO END. UPDATE ISSUED AT 611 PM MST SUN NOV 24 2013 UPDATED SNOW GRIDS TO INCREASE AMOUNTS. BAND HAS BEEN PRODUCING A QUICK 1 TO 4 INCHES ACROSS EL PASO AND PUEBLO COUNTIES. WITH TRAJECTORY OF SNOW ENHANCEMENT HEADED TOWARDS THE WET MOUNTAINS...ADDED THE LOWER ELEVATIONS OF THE WETS AND THE LOWER ELEVATIONS OF THE SANGRES TO THE WINTER WEATHER ADVISORY. HAVE AN SPS OUT FOR EL PASO AND PUEBLO COUNTIES FOR NOW. ITS POSSIBLE THAT THESE AREAS MAY NEED TO BE UPGRADED TO AN ADVISORY...BUT THE VAST SPATIAL VARIABILITY BETWEEN THE HEAVY SNOW AND WHERE THERE IS NO SNOW ACROSS THESE ZONES MAKES THIS A LESS FAVORABLE OPTION FOR NOW...BUT WILL CONTINUE TO MONITOR AND REASSESS AS NEEDED. -KT UPDATE ISSUED AT 459 PM MST SUN NOV 24 2013 QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE OVER THE LOWER ELEVATIONS. -KT && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 ...SNOW WINDING DOWN ON MONDAY... UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL. LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE CHANGES THERE. SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS. ROSE .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS. FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS. -TLM- && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1030 PM MST SUN NOV 24 2013 THE UPPER LOW TRACKING ACROSS NORTHERN NM WAS CONTINUING TO DRAW MOISTURE AND SFC FLOW OUT OF THE N-NE. SNOWFALL BLOSSOMED UNDER THIS FLOW AROUND 4 PM THIS EVE AND HAS CONTINUED THROUGHOUT THE NIGHT...WITH THE HEAVIEST BAND INITIALLY OVER SOUTHERN EL PASO COUNTY GRADUALLY SAGGING TO THE SOUTH. HEAVIEST HIT AREAS HAVE BEEN THE WET MT VALLEY...EASTERN MTS...AND LOCALIZED AREAS ON THE BACKSIDE OF THE SANGRES WHERE SNOW HAS SEEMINGLY SPILLED OVER THE RIDGE. THE HEAVIER SNOWFALL HAS NOW DROPPED SOUTH...WHERE IFR TO LIFR CONDITIONS ARE AFFECTING KALS AND KTAD. FURTHER NORTH...KPUB REPORTED MVFR TO IFR CONDITIONS...AND KCOS HAS NOW CLEARED OUT OF THE SNOW WITH VFR CONDITIONS. THE UPPER LOW WILL CONTINUE EAST OVERNIGHT AND THROUGH TOMORROW...AND SNOW IS EXPECTED TO DIMINISH OVERNIGHT ACROSS THE SOUTHERN TIER BETWEEN 08Z AND 10Z. STRONG AND GUSTY NORTHERLY WINDS WILL SETTLE IN ACROSS THE AREA ON THE BACK SIDE OF THE DEPARTING LOW...LASTING UNTIL AROUND 15Z. MOORE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 AM MST EARLY THIS MORNING FOR COZ060-066-072-073. WINTER STORM WARNING UNTIL 5 AM MST EARLY THIS MORNING FOR COZ068. WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR COZ074- 075-079-080-087-088. && $$ UPDATE...PETERSEN SHORT TERM...ROSE LONG TERM...TM AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1041 PM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 611 PM MST SUN NOV 24 2013 UPDATED SNOW GRIDS TO INCREASE AMOUNTS. BAND HAS BEEN PRODUCING A QUICK 1 TO 4 INCHES ACROSS EL PASO AND PUEBLO COUNTIES. WITH TRAJECTORY OF SNOW ENHANCEMENT HEADED TOWARDS THE WET MOUNTAINS...ADDED THE LOWER ELEVATIONS OF THE WETS AND THE LOWER ELEVATIONS OF THE SANGRES TO THE WINTER WEATHER ADVISORY. HAVE AN SPS OUT FOR EL PASO AND PUEBLO COUNTIES FOR NOW. ITS POSSIBLE THAT THESE AREAS MAY NEED TO BE UPGRADED TO AN ADVISORY...BUT THE VAST SPATIAL VARIABILITY BETWEEN THE HEAVY SNOW AND WHERE THERE IS NO SNOW ACROSS THESE ZONES MAKES THIS A LESS FAVORABLE OPTION FOR NOW...BUT WILL CONTINUE TO MONITOR AND REASSESS AS NEEDED. -KT UPDATE ISSUED AT 459 PM MST SUN NOV 24 2013 QUICK UPDATE TO BUMP UP POPS ACROSS EL PASO AND NORTHWEST PUEBLO COUNTIES WHERE DEFORMATION BAND HAS SET UP. GETTING REPORTS OF MODERATE SNOW WITHIN THIS BAND AND SUSPECT A QUICK INCH OR TWO WILL BE POSSIBLE WITHIN THE NEXT HOUR OR TWO. BASED ON SHORT RANGE HIGH RES MODELS...FOCUS FOR HEAVIER SNOWFALL WILL SHIFT INTO THE NORTHEAST FACING SLOPES OF THE SOUTHEAST MOUNTAINS AND FREMONT COUNTY AS THE EVENING PROGRESSES. HOWEVER MODELS ARE NOT RESOLVING THE CURRENT SNOW BAND VERY WELL...SO EXPECT A HIGHLY EVOLVING FORECAST TONIGHT AS THESE DETAILS GET RESOLVED. FOR NOW...HAVE BUMPED UP POPS INTO THE LIKELY CATEGORY FOR EL PASO...FREMONT...AND WESTERN PUEBLO COUNTIES THROUGH 06Z. IF BAND STALLS OVER ANY PARTICULAR AREA...SOME LOCAL ACCUMULATIONS OF UP TO 4 INCHES WILL BE POSSIBLE OVER THE LOWER ELEVATIONS. -KT && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 ...SNOW WINDING DOWN ON MONDAY... UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL. LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE CHANGES THERE. SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS. ROSE .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS. FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS. -TLM- && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1030 PM MST SUN NOV 24 2013 THE UPPER LOW TRACKING ACROSS NORTHERN NM WAS CONTINUING TO DRAW MOISTURE AND SFC FLOW OUT OF THE N-NE. SNOWFALL BLOSSOMED UNDER THIS FLOW AROUND 4 PM THIS EVE AND HAS CONTINUED THROUGHOUT THE NIGHT...WITH THE HEAVIEST BAND INITIALLY OVER SOUTHERN EL PASO COUNTY GRADUALLY SAGGING TO THE SOUTH. HEAVIEST HIT AREAS HAVE BEEN THE WET MT VALLEY...EASTERN MTS...AND LOCALIZED AREAS ON THE BACKSIDE OF THE SANGRES WHERE SNOW HAS SEEMINGLY SPILLED OVER THE RIDGE. THE HEAVIER SNOWFALL HAS NOW DROPPED SOUTH...WHERE IFR TO LIFR CONDITIONS ARE AFFECTING KALS AND KTAD. FURTHER NORTH...KPUB REPORTED MVFR TO IFR CONDITIONS...AND KCOS HAS NOW CLEARED OUT OF THE SNOW WITH VFR CONDITIONS. THE UPPER LOW WILL CONTINUE EAST OVERNIGHT AND THROUGH TOMORROW...AND SNOW IS EXPECTED TO DIMINISH OVERNIGHT ACROSS THE SOUTHERN TIER BETWEEN 08Z AND 10Z. STRONG AND GUSTY NORTHERLY WINDS WILL SETTLE IN ACROSS THE AREA ON THE BACK SIDE OF THE DEPARTING LOW...LASTING UNTIL AROUND 15Z. MOORE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ060-066- 072>075-079-080. WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ068. && $$ UPDATE...KT SHORT TERM...ROSE LONG TERM...TM AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1007 PM EST TUE NOV 26 2013 .SYNOPSIS... LOW PRESSURE OVER THE SOUTHEAST STATES WILL INTENSIFY AND MOVE UP THE COAST TONIGHT...PASSING OVER THE AREA ON WEDNESDAY AND THEN HEADING INTO EASTERN CANADA WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BUILDS IN FROM THURSDAY THROUGH SATURDAY...AND MOVE OFF THE NEW ENGLAND COAST ON SUNDAY. A COASTAL FRONT WILL DEVELOP ON SUNDAY AND REMAIN INTO MONDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT AND MOVE ALONG THE COAST ON TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... FORECAST MAINLY ON TRACK...WITH MAIN ADJUSTMENT TO T/TDS. HAVE EXTENDED WINTER WEATHER ADVISORY FOR ORANGE COUNTY UNTIL 1 AM. WINDS HAVE BACKED TO THE NORTH ACROSS MAINLY THE EASTERN HALF OF ORANGE COUNTY...ALLOWING TEMPS TO HOLD AROUND FREEZING. THIS WILL RESULT IN POCKETS OF FREEZING RAIN AND ICY TRAVEL UNTIL AROUND MIDNIGHT. MARGINAL TEMPS SHOULD CONTINUE TO CREEP HIGHER AS STRONG WAA ENSUES TOWARDS MIDNIGHT...CHANGING PRECIP TO ALL RAIN AFTER MIDNIGHT. ELSEWHERE...RAIN WILL INCREASE IN INTENSITY TONIGHT AS PRIMARY LOW PRESSURE WEAKENS ALONG A LOW LEVEL BAROCLINIC ZONE ALONG THE COASTAL PLAIN...AND GIVES WAY TO A SECONDARY LOW OVER THE MID ATLANTIC FORMING UNDER THE STRENGTHENING RIGHT ENTRANCE REGION OF A DIFFLUENT UPPER JET STREAK APPROACHING FROM THE WEST AS A NORTHERN/SOUTHERN STREAMS PHASE ALOFT. THIS IS EVIDENT IN RAPID PRESSURE FALLS THIS EVENING ACROSS THE DC AREA. A S-SE LOW LEVEL JET WILL INTENSIFY EAST OF THE LOW OVERNIGHT... TRANSPORTING ATLANTIC/GULF MOISTURE INTO THE REGION AND PROVIDING AMPLE LOW LEVEL CONVERGENCE/LIFT FOR HEAVY RAIN. OROGRAPHIC LIFT WILL ALSO COME INTO PLAY NORTH/WEST OF NYC GIVEN THE LOW LEVEL SE FLOW TO START. GIVEN THESE FACTORS THE FLOOD WATCH CONTINUES FOR THE POTENTIAL FOR AREAL/URBAN FLOODING AND FLOODING OF SMALL STREAMS. SEE HYDROLOGY SECTIONS FOR MORE DETAILS. THE LLJ ALSO LOOKS STRONG ENOUGH TO SUPPORT STRONG SE-S WINDS ALONG THE COAST...SO THE WIND ADVY CONTINUES. VERY STRONG NAM LLJ WITH 85-95 KT AT H8 MAY LOOK LIKE AN OUTLIER COMPARED TO WEAKER/FARTHER EAST GFS/ECMWF...BUT LATEST RUNS OF THE RAP DO LEND IT SUPPORT SO AM NOT WILLING TO DISCOUNT IT. SFC-H8 INVERSION SHOULD PREVENT THE STRONGEST OF THESE WINDS FROM MIXING DOWN. HOWEVER HAVE A NAGGING CONCERN THAT DUCTED GRAVITY WAVES COULD AID IN DOWNWARD MOMENTUM TRANSPORT TOWARD MORNING PER AKQ RESEARCH...AS WEAK INSTABILITY MOVES IN ALOFT JUST NORTH OF AN APPROACHING WARM FRONT...AND AS THE UPPER JET STREAK APPROACHES THE DOWNSTREAM INFLECTION POINT BETWEEN THE UPPER TROUGH TO THE WEST AND OFFSHORE RIDGING...SO POTENTIAL FOR 60+ MPH WIND GUSTS ACROSS LONG ISLAND AND COASTAL SE CT WILL HAVE TO BE WATCHED. MOST LIKELY SCENARIO WILL BE FOR SUSTAINED WINDS 25-35 MPH WITH GUSTS 45-50 MPH...MAINLY IN/NEAR NYC AND ALONG THE COAST BEGINNING LATE TONIGHT. THERE COULD BE A FEW RUMBLES OF THUNDER LATE AS ELEVATED INSTABILITY MOVES OVER THE AREA. SEE TIDES AND COASTAL FLOODING SECTIONS FOR MINOR COASTAL FLOODING AND BEACH EROSION CONCERNS. TEMPS WILL BE ON THE RISE TONIGHT...REACHING THE MID AND UPPER 50S BY MORNING. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... THE LOW WILL BE MOVING ACROSS THE REGION WED MORNING INTO EARLY AFTERNOON...THEN RE-CONSOLIDATING TO THE NORTH IN THE AFTERNOON. HEAVY RAIN...STRONG SOUTHERLY WINDS AND ISOLD RUMBLES OF THUNDER WILL STILL BE ONGOING INITIALLY...THEN SHOULD SHIFT TO THE EAST ACROSS ERN LONG ISLAND/CT DURING LATE MORNING AND LIFT UP INTO NEW ENGLAND BY AFTERNOON AS THIS TAKES PLACE. ENDED WIND ADVY EARLIER THAN ORIGINALLY FCST SINCE THE LOW TRACK SHOULD BE SLIGHTLY FARTHER EAST...WITH THE LLJ ALSO PASSING TO THE EAST SOONER. RAIN SHOULD LESSEN IN INTENSITY AS WELL AS AS THE LLJ PASSES TO THE EAST. AS THE LOW MOVES OVER THE AREA...THERE SHOULD BE A RELATIVE LULL IN WINDS FROM LATE MORNING INTO EARLY AFTERNOON...THEN STRONG NW WINDS WILL REDEVELOP BY EVENING AS THE LOW CONTINUES TO INTENSIFY AND SHOULD CONTINUE INTO THE NIGHT...SUSTAINED AT 20-30 MPH WITH GUSTS UP TO 40 MPH...POSSIBLY STRONGER IN NYC METRO AND LONG ISLAND WHERE ANOTHER WIND ADVY MAY BE NEEDED. STILL EXPECT SCT SHOWERS IN THE EVENING AS THE UPPER TROUGH MOVES ACROSS...AND LOW LEVEL CAA SHOULD CHANGE ANY PRECIP OVER TO SNOW FROM NYC NORTH/WEST. SOME INTERIOR AREAS COULD SEE A LIGHT COATING OF ACCUMULATION OF SNOW BEFORE ALL PRECIP ENDS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... VIGOROUS SHORTWAVE IS ROTATING EAST OF THE REGION EARLY THURSDAY MORNING AS BROAD UPPER TROUGH REMAINS ACROSS THE NORTHEAST. ANOTHER SHORTWAVE ROTATES THROUGH THE TROUGH LATE THURSDAY INTO THURSDAY NIGHT. MEANWHILE AT THE SURFACE LOW PRESSURE WILL BE NORTH AND EAST OF THE AREA AND CONTINUING TO MOVE NORTH DURING THE DAY INTO THURSDAY NIGHT AS HIGH PRESSURE BUILDS TO THE WEST. INCREASING SUBSIDENCE BEHIND THE LOW WILL KEEP AREA PRECIPITATION FREE THURSDAY...ALTHOUGH CLOUDS WILL LINGER EARLY IN THE DAY. UPPER FLOW BECOMES MORE ZONAL FRIDAY AND INTO THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS OVER THE REGION. WARM ADVECTION SETS UP LATE SATURDAY NIGHT AND INTO SUNDAY AS HIGH PRESSURE MOVES EAST AND NEXT SHORTWAVE APPROACHES FROM THE GREAT LAKES. LIFT IS RATHER WEAK AT THIS TIME AND MOISTURE LIMITED HOWEVER...THERE IS A VERY LOW PROBABILITY OF LIGHT PRECIPITATION LATE SATURDAY NIGHT. SUNDAY WILL BE A BETTER CHANCE AS ADVECTION CONTINUES AND GULF MOISTURE MOVES INTO THE AREA. AS THE HIGH RETREATS TO THE NORTHEAST SATURDAY NIGHT INTO SUNDAY...COLD AIR DAMNING IS POSSIBLE AND MIXED PRECIPITATION WILL BE POSSIBLE INLAND AS COASTAL AREAS WARM IN THE SOUTHERLY FLOW. A COASTAL FRONT DEVELOPS SUNDAY INTO MONDAY AS A WEAK SOUTHERN STREAM SHORTWAVE MOVES OUT OF THE SOUTHWEST AND INTO THE GULF COAST REGION. THIS WAVE WILL DEVELOP A LOW ALONG THE COASTAL FRONT MONDAY INTO TUESDAY. STILL SOME UNCERTAINTY WITH THE TRACK OF LOW WITH THE ECMWF CLOSER TO THE COAST AND THE GFS MOVING THE LOW FARTHER OFF THE SOUTHEASTERN COAST AND KEEPING THE REGION ON THE NORTHWESTERN EDGE OF THE PRECIPITATION TUESDAY. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... **HIGH IMPACT AVIATION WEATHER EVENT FOR TONIGHT AND WEDNESDAY** DETERIORATING CONDITIONS OVERNIGHT WITH AN APPROACHING LOW PRESSURE SYSTEM. VARYING IFR/LIFR CONDITIONS THROUGH THE NIGHT AND TOMORROW MORNING...WITH GRADUAL IMPROVEMENT TOMORROW AFTN INTO TOMORROW NIGHT. WINDS ELY 5-10 KTS THIS EVENING..BCMG ESE AROUND 10 KTS...WITH GUSTS INTO THE 20S/30S BY 05Z. WIND SHEAR BECOMES AN ISSUE NYC TERMINALS AND EAST 08Z-14Z TOMORROW...WITH SLY WINDS UP TO 70 KTS AT 2000 FT. WINDS GRADUALLY DIMINISH AND SHIFT TO THE SW THEN NW BY TOMORROW AFTN. TIMING OF WIND SHIFTS MAY BE 1-2 HOURS. GUSTS WILL REMAIN ACROSS THE ENTIRE INTO TOMORROW NIGHT. EXPECT IFR AND LIFR CIGS AS HEAVIER PCPN MOVES IN AFTER 03Z. BEST CHC FOR LIFR WILL BE BETWEEN 07Z AND 15Z. PCPN LINGERS DURING THE DAY TOMORROW...WITH GRADUALLY IMPROVING CIGS AFTER 15Z. PCPN SHOULD REMAIN ALL RAIN FROM HERE ON OUT. .OUTLOOK FOR 03Z THURSDAY THROUGH MONDAY... .WED NGT. MVFR EARLY...BECOMING VFR. CHC -SHSNRA. W-NW WINDS 20-25G35KT. .THU...VFR. NW WINDS 20-25G30-35KT EARLY SLOWLY DIMINISHING TO G20KT BY EVENING. .THU NGT-SAT...VFR. .SUN AND MON...MVFR CIG. -DZ / -RA. SE SFC FLOW 10-15 KT. && .MARINE... THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN TONIGHT AHEAD OF AN ADVANCING STORM SYSTEM TRACKING FROM THE SOUTHEASTERN TO COASTAL MID ATLANTIC STATES TONIGHT...WITH WIND GUSTS TO GALE LEVELS DEVELOPING AFTER MIDNIGHT. A FEW GUSTS TO STORM FORCE MAY BE POSSIBLE TOWARD MORNING...MAINLY ON THE ERN OCEAN WATERS...BUT THESE SHOULD BE BRIEF AT BEST AND SO DID NOT UPGRADE ANY AREAS TO A STORM WARNING. WILL USE SPECIAL MARINE WARNINGS TO ADDRESS ANY WIND GUSTS OF 48 KT OR HIGHER IN ISOLATED STRONGER CONVECTION. SEAS COULD BUILD AS HIGH AS 16 FT ON THE ERN OCEAN WATERS WITH THE STRONGEST SOUTHERLY WINDS. THERE COULD BE A LULL IN WINDS FROM LATE WED MORNING INTO THE AFTERNOON...BUT THEN NW GALES ARE EXPECTED WED NIGHT INTO THU MORNING...WITH SEAS UP TO 15 FT EXPECTED WED NIGHT ON THE OCEAN AND AS HIGH AS 7 FT ON LONG ISLAND SOUND AS THE SURFACE LOW CONTINUES TO TRACK TO THE NORTH THROUGH CANADA AND HIGH PRESSURE BUILDS TO THE WEST. THE WIND WILL BE DIMINISHING THROUGH THE DAY THURSDAY...SUBSIDING BELOW GALE FORCE DURING THE AFTERNOON...AND THEN QUICKLY FALLING BELOW 25 KT DURING THURSDAY EVENING. VERY ROUGH SEAS ON THE OCEAN WATERS SUBSIDE DURING THURSDAY IN THE WEST TO NORTHWEST FLOW. BY LATE THURSDAY NIGHT SEAS ARE EXPECTED TO FALL BELOW 5 FT AS THE WESTERLY FLOW DIMINISHES. WIND AND SEAS REMAIN BELOW ADVISORY LEVELS FRIDAY INTO SUNDAY. DEPENDING ON THE STRENGTH OF THE WIND AROUND A DEPARTING HIGH AND A DEVELOPING TROUGH ALONG THE COAST...SEAS ON THE OCEAN WATERS MAY BUILD BACK UP TO SMALL CRAFT LEVELS LATE SUNDAY INTO SUNDAY NIGHT. && .HYDROLOGY... WIDESPREAD RAINFALL TOTALS FORECAST RANGE BETWEEN 2 AND 3 INCHES WITH LOCAL AMOUNTS UP TO 4 INCHES. DUE TO RECENT PROLONGED DRY CONDITIONS...MAIN STEM RIVER FLOODING IS NOT EXPECTED. HOWEVER...THERE IS ENOUGH CHANCE OF URBAN/AREAL/SMALL STREAM FLOODING...ESPECIALLY WHERE STORM DRAINS ARE CLOGGED BY LEAVES AND ESSENTIALLY WHERE THERE IS MORE RUNOFF. ADDITIONALLY...LOW-LYING COASTAL AREAS MAY EXPERIENCE EXACERBATED ROAD FLOODING DURING TIMES OF HIGH TIDE WEDNESDAY MORNING. LIGHT PRECIPITATION IS POSSIBLE SUNDAY INTO TUESDAY...WITH A TOTAL OF UP TO A HALF INCH EXPECTED AT THIS TIME. && .TIDES/COASTAL FLOODING... A GALE FORCE SE FLOW WILL RAPIDLY DEVELOP AHEAD OF DEEPENING LOW PRESSURE LATE TONIGHT...BEFORE VEERING TO THE S WEDNESDAY MORNING. A STORM SURGE OF 2 TO 2 1/2 FT...LOCALLY 3 FT IS EXPECTED. THE PEAK SURGE COINCIDES BEST WITH THE TIMING OF THE MORNING HIGH TIDE CYCLE IN WESTERN LONG ISLAND SOUND AND PECONIC BAY. AN ADVISORY HAS BEEN ISSUED IN THESE LOCATIONS WITH COMBINED THREAT OF STORM TIDE...WAVE SPLASH-OVER...AND HEAVY RAIN CAUSING WIDESPREAD MINOR IMPACTS. ELSEWHERE...TIMING OF PEAK SURGE AND HIGH TIDE APPEARS TO BE OFFSET...WITH ONLY LOCALIZED ISSUES EXPECTED WITH WEDNESDAY MORNING HIGH TIDE DUE TO STORM TIDE AND HEAVY RAIN. A COASTAL FLOOD STATEMENT HAS BEEN ISSUED TO ADDRESS THIS THREAT. FOR THE LATE AFTERNOON/EVENING HIGH TIDE CYCLE...WITH FLOW EXPECTED TO BEGIN TURN OFFSHORE WOULD EXPECT SURGE VALUES TO BEGIN TO FALL RAPIDLY FROM AFTERNOON ON. THE ONLY AREA TO MONITOR WOULD BE THE SOUTH SHORE BACK BAYS WITH HIGH SURF LIMITING TIDAL DRAINAGE. HIGH SURF AND MINOR EROSION ISSUES ARE EXPECTED LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT FROM BATTERING SURF OF 7-11 FT. MAIN CONCERN WILL BE THE VULNERABLE DUNES AND BREACH LOCATIONS POST SANDY. A HIGH SURF ADVISORY HAS BEEN ISSUED TO ADDRESS THIS THREAT. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR CTZ005>012. WIND ADVISORY UNTIL 2 PM EST WEDNESDAY FOR CTZ008-011-012. WIND ADVISORY UNTIL 9 AM EST WEDNESDAY FOR CTZ007-009-010. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR CTZ009-010. NY...FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR NYZ067>075-078>081- 176>179. WIND ADVISORY UNTIL 2 PM EST WEDNESDAY FOR NYZ078>081-177-179. COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST WEDNESDAY FOR NYZ079-081. WIND ADVISORY UNTIL 9 AM EST WEDNESDAY FOR NYZ071>075-176-178. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR NYZ071-073. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ067. HIGH SURF ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR NYZ080-081-178-179. NJ...FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR NJZ002-004-006- 103>108. WIND ADVISORY UNTIL 9 AM EST WEDNESDAY FOR NJZ006. MARINE...GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ330-335-338-340- 345-350-353-355. && $$ SYNOPSIS...GOODMAN/MET NEAR TERM...GOODMAN/NV SHORT TERM...GOODMAN LONG TERM...MET AVIATION...SEARS MARINE...GOODMAN/MET/NV HYDROLOGY...GOODMAN/MET TIDES/COASTAL FLOODING...NV EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
723 PM EST TUE NOV 26 2013 .SYNOPSIS... LOW PRESSURE OVER THE SOUTHEAST STATES WILL INTENSIFY AND MOVE UP THE COAST TONIGHT...PASSING OVER THE AREA ON WEDNESDAY AND THEN HEADING INTO EASTERN CANADA WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BUILDS IN FROM THURSDAY THROUGH SATURDAY...AND MOVE OFF THE NEW ENGLAND COAST ON SUNDAY. A COASTAL FRONT WILL DEVELOP ON SUNDAY AND REMAIN INTO MONDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT AND MOVE ALONG THE COAST ON TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... FORECAST ON TRACK...WITH OVERUNNING PRECIP EXPECTED TO CONTINUE TO INCREASE IN INTENSITY THROUGH THE EVENING...AS LOW PRESSURE OVER THE SOUTHEAST US INTENSIFIES AND TRACKS NE TOWARDS THE REGION. IMPENDING STORM WILL BRING A VARIETY OF WEATHER HAZARDS BEGINNING TONIGHT. WILL ALLOW WINTER WX ADVISORY TO CONTIUE FOR A MIX OF RAIN AND SLEET AND POCKETS OF FZRA OVER ORANGE COUNTY. EXPECTATION WITH MARGINAL TEMPS CONTINUE TO CREEP HIGHER AND INCREASING WAA...TEMPS SHOULD CONTINUE TO RISE AND CHANGE PRECIP TO ALL RAIN BY LATE EVENING. ELSEWHERE...RAIN WILL INCREASE IN INTENSITY FROM LATE EVENING ON AS PRIMARY LOW PRESSURE WEAKENS ALONG A LOW LEVEL BAROCLINIC ZONE ALONG THE COASTAL PLAIN...AND GIVES WAY TO A SECONDARY LOW OVER THE MID ATLANTIC FORMING UNDER THE STRENGTHENING RIGHT ENTRANCE REGION OF A DIFLUENT UPPER JET STREAK APPROACHING FROM THE WEST AS A NORTHERN/SOUTHERN STREAMS PHASE ALOFT. A S-SE LOW LEVEL JET WILL INTENSIFY EAST OF THE LOW OVERNIGHT... TRANSPORTING ATLANTIC/GULF MOISTURE INTO THE REGION AND PROVIDING AMPLE LOW LEVEL CONVERGENCE/LIFT FOR HEAVY RAIN. OROGRAPHIC LIFT WILL ALSO COME INTO PLAY NORTH/WEST OF NYC GIVEN THE LOW LEVEL SE FLOW TO START. GIVEN THESE FACTORS THE POTENTIAL FOR AREAL/URBAN FLOODING AND FLOODING OF SMALL STREAMS NOW LOOKS GREAT ENOUGH TO WARRANT A FLOOD WATCH. THE LLJ ALSO LOOKS STRONG ENOUGH TO SUPPORT STRONG SE-S WINDS ALONG THE COAST...SO THE WIND ADVY CONTINUES. VERY STRONG NAM LLJ WITH 85-95 KT AT H8 MAY LOOK LIKE AN OUTLIER COMPARED TO WEAKER/FARTHER EAST GFS/ECMWF...BUT LATEST RUNS OF THE RAP DO LEND IT SUPPORT SO AM NOT WILLING TO DISCOUNT IT. SFC-H8 INVERSION SHOULD PREVENT THE STRONGEST OF THESE WINDS FROM MIXING DOWN. HOWEVER HAVE A NAGGING CONCERN THAT DUCTED GRAVITY WAVES COULD AID IN DOWNWARD MOMENTUM TRANSPORT TOWARD MORNING PER AKQ RESEARCH...AS WEAK INSTABILITY MOVES IN ALOFT JUST NORTH OF AN APPROACHING WARM FRONT...AND AS THE UPPER JET STREAK APPROACHES THE DOWNSTREAM INFLECTION POINT BETWEEN THE UPPER TROUGH TO THE WEST AND OFFSHORE RIDGING...SO POTENTIAL FOR 60+ MPH WIND GUSTS ACROSS LONG ISLAND AND COASTAL SE CT WILL HAVE TO BE WATCHED. MOST LIKELY SCENARIO WILL BE FOR SUSTAINED WINDS 25-35 MPH WITH GUSTS 45-50 MPH...MAINLY IN/NEAR NYC AND ALONG THE COAST BEGINNING LATE TONIGHT. THERE COULD BE A FEW RUMBLES OF THUNDER LATE AS ELEVATED INSTABILITY MOVES OVER THE AREA. TEMPS WILL BE ON THE RISE TONIGHT...REACHING THE MID AND UPPER 50S BY MORNING. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... THE LOW WILL BE MOVING ACROSS THE REGION WED MORNING INTO EARLY AFTERNOON...THEN RE-CONSOLIDATING TO THE NORTH IN THE AFTERNOON. HEAVY RAIN...STRONG SOUTHERLY WINDS AND ISOLD RUMBLES OF THUNDER WILL STILL BE ONGOING INITIALLY...THEN SHOULD SHIFT TO THE EAST ACROSS ERN LONG ISLAND/CT DURING LATE MORNING AND LIFT UP INTO NEW ENGLAND BY AFTERNOON AS THIS TAKES PLACE. ENDED WIND ADVY EARLIER THAN ORIGINALLY FCST SINCE THE LOW TRACK SHOULD BE SLIGHTLY FARTHER EAST...WITH THE LLJ ALSO PASSING TO THE EAST SOONER. RAIN SHOULD LESSEN IN INTENSITY AS WELL AS AS THE LLJ PASSES TO THE EAST. AS THE LOW MOVES OVER THE AREA...THERE SHOULD BE A RELATIVE LULL IN WINDS FROM LATE MORNING INTO EARLY AFTERNOON...THEN STRONG NW WINDS WILL REDEVELOP BY EVENING AS THE LOW CONTINUES TO INTENSIFY AND SHOULD CONTINUE INTO THE NIGHT...SUSTAINED AT 20-30 MPH WITH GUSTS UP TO 40 MPH...POSSIBLY STRONGER IN NYC METRO AND LONG ISLAND WHERE ANOTHER WIND ADVY MAY BE NEEDED. STILL EXPECT SCT SHOWERS IN THE EVENING AS THE UPPER TROUGH MOVES ACROSS...AND LOW LEVEL CAA SHOULD CHANGE ANY PRECIP OVER TO SNOW FROM NYC NORTH/WEST. SOME INTERIOR AREAS COULD SEE A LIGHT COATING OF ACCUMULATION OF SNOW BEFORE ALL PRECIP ENDS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... VIGOROUS SHORTWAVE IS ROTATING EAST OF THE REGION EARLY THURSDAY MORNING AS BROAD UPPER TROUGH REMAINS ACROSS THE NORTHEAST. ANOTHER SHORTWAVE ROTATES THROUGH THE TROUGH LATE THURSDAY INTO THURSDAY NIGHT. MEANWHILE AT THE SURFACE LOW PRESSURE WILL BE NORTH AND EAST OF THE AREA AND CONTINUING TO MOVE NORTH DURING THE DAY INTO THURSDAY NIGHT AS HIGH PRESSURE BUILDS TO THE WEST. INCREASING SUBSIDENCE BEHIND THE LOW WILL KEEP AREA PRECIPITATION FREE THURSDAY...ALTHOUGH CLOUDS WILL LINGER EARLY IN THE DAY. UPPER FLOW BECOMES MORE ZONAL FRIDAY AND INTO THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS OVER THE REGION. WARM ADVECTION SETS UP LATE SATURDAY NIGHT AND INTO SUNDAY AS HIGH PRESSURE MOVES EAST AND NEXT SHORTWAVE APPROACHES FROM THE GREAT LAKES. LIFT IS RATHER WEAK AT THIS TIME AND MOISTURE LIMITED HOWEVER...THERE IS A VERY LOW PROBABILITY OF LIGHT PRECIPITATION LATE SATURDAY NIGHT. SUNDAY WILL BE A BETTER CHANCE AS ADVECTION CONTINUES AND GULF MOISTURE MOVES INTO THE AREA. AS THE HIGH RETREATS TO THE NORTHEAST SATURDAY NIGHT INTO SUNDAY...COLD AIR DAMNING IS POSSIBLE AND MIXED PRECIPITATION WILL BE POSSIBLE INLAND AS COASTAL AREAS WARM IN THE SOUTHERLY FLOW. A COASTAL FRONT DEVELOPS SUNDAY INTO MONDAY AS A WEAK SOUTHERN STREAM SHORTWAVE MOVES OUT OF THE SOUTHWEST AND INTO THE GULF COAST REGION. THIS WAVE WILL DEVELOP A LOW ALONG THE COASTAL FRONT MONDAY INTO TUESDAY. STILL SOME UNCERTAINTY WITH THE TRACK OF LOW WITH THE ECMWF CLOSER TO THE COAST AND THE GFS MOVING THE LOW FARTHER OFF THE SOUTHEASTERN COAST AND KEEPING THE REGION ON THE NORTHWESTERN EDGE OF THE PRECIPITATION TUESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... **HIGH IMPACT AVIATION WEATHER EVENT FOR TONIGHT AND WEDNESDAY** DETERIORATING CONDITIONS THIS EVENING AND OVERNIGHT WITH AN APPROACHING LOW PRESSURE SYSTEM. BRIEF PERIOD OF VFR THROUGH 01Z WILL GIVE WAY QUICKLY TO IFR CIGS/VIS. WINDS ELY 5-10 KTS THIS EVENING..BCMG ESE AROUND 10 KTS...WITH GUSTS INTO THE 20S/30S BY 06Z. WIND SHEAR BECOMES AN ISSUE NYC TERMINALS AND EAST 08Z-14Z TOMORROW...WITH SLY WINDS UP TO 70 KTS AT 2000 FT. WINDS GRADUALLY DIMINISH AND SHIFT TO THE SW THEN NW BY TOMORROW AFTN. TIMING OF WIND SHIFTS MAY BE 1-2 HOURS. EXPECT IFR AND PSBL PERIOD OF LIFR CIGS AS HEAVIER PCPN MOVES IN AFTER 02Z. BEST CHC FOR LIFR WILL BE BETWEEN 07Z AND 15Z. PCPN LINGERS DURING THE DAY TOMORROW...WITH GRADUALLY IMPROVING CIGS AFTER 15Z. 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) KJFK FCSTER COMMENTS: MOD CONFIDENCE FORECAST. START TIME OF GUSTS MAY BE +1-2 HRS. CIGS MAY LINGER AT VFR THROUGH 02Z. KLGA FCSTER COMMENTS: MOD CONFIDENCE FORECAST. BRIEF PERIOD OF IFR CIGS PRIOR TO 06Z. START TIME OF GUSTS MAY BE +1-2 HOURS. KEWR FCSTER COMMENTS: MOD CONFIDENCE FORECAST. START TIME OF GUSTS MAY BE +1-2 HOURS. IFR CONDITIONS MAY START 1 HOUR LATER. KTEB FCSTER COMMENTS: MOD CONFIDENCE FORECAST. START TIME OF GUSTS MAY BE +1-2 HOURS. IFR CONDITIONS MAY START 1 HOUR LATER. KHPN FCSTER COMMENTS: MOD CONFIDENCE FORECAST. KISP FCSTER COMMENTS: MOD CONFIDENCE FORECAST. LOWER CIGS MAY MOVE IN 1 HOUR SOONER. .OUTLOOK FOR 00Z THURSDAY THROUGH MONDAY... .WED NGT. MVFR...BECOMING VFR. CHC -SHSNRA. W/NW WINDS 20-25G35KT. .THU...VFR. NW WINDS 20-25G30-35KT EARLY SLOWLY DIMINISHING TO G20KT BY EVENING. .THU NGT-SAT...VFR. .SUN AND MON...MVFR CIG. -DZ / -RA. SE SFC FLOW 10-15 KT. && .MARINE... THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN TONIGHT AHEAD OF AN ADVANCING STORM SYSTEM TRACKING FROM THE SOUTHEASTERN TO COASTAL MID ATLANTIC STATES TONIGHT...WITH WIND GUSTS TO GALE LEVELS DEVELOPING AFTER MIDNIGHT. A FEW GUSTS TO STORM FORCE MAY BE POSSIBLE TOWARD MORNING...MAINLY ON THE ERN OCEAN WATERS...BUT THESE SHOULD BE BRIEF AT BEST AND SO DID NOT UPGRADE ANY AREAS TO A STORM WARNING. WILL USE SPECIAL MARINE WARNINGS TO ADDRESS ANY WIND GUSTS OF 48 KT OR HIGHER IN ISOLATED STRONGER CONVECTION. SEAS COULD BUILD AS HIGH AS 16 FT ON THE ERN OCEAN WATERS WITH THE STRONGEST SOUTHERLY WINDS. THERE COULD BE A LULL IN WINDS FROM LATE WED MORNING INTO THE AFTERNOON...BUT THEN NW GALES ARE EXPECTED WED NIGHT INTO THU MORNING...WITH SEAS UP TO 15 FT EXPECTED WED NIGHT ON THE OCEAN AND AS HIGH AS 7 FT ON LONG ISLAND SOUND AS THE SURFACE LOW CONTINUES TO TRACK TO THE NORTH THROUGH CANADA AND HIGH PRESSURE BUILDS TO THE WEST. THE WIND WILL BE DIMINISHING THROUGH THE DAY THURSDAY...SUBSIDING BELOW GALE FORCE DURING THE AFTERNOON...AND THEN QUICKLY FALLING BELOW 25 KT DURING THURSDAY EVENING. VERY ROUGH SEAS ON THE OCEAN WATERS SUBSIDE DURING THURSDAY IN THE WEST TO NORTHWEST FLOW. BY LATE THURSDAY NIGHT SEAS ARE EXPECTED TO FALL BELOW 5 FT AS THE WESTERLY FLOW DIMINISHES. WIND AND SEAS REMAIN BELOW ADVISORY LEVELS FRIDAY INTO SUNDAY. DEPENDING ON THE STRENGTH OF THE WIND AROUND A DEPARTING HIGH AND A DEVELOPING TROUGH ALONG THE COAST...SEAS ON THE OCEAN WATERS MAY BUILD BACK UP TO SMALL CRAFT LEVELS LATE SUNDAY INTO SUNDAY NIGHT. && .HYDROLOGY... WIDESPREAD RAINFALL TOTALS FORECAST RANGE BETWEEN 2 AND 3 INCHES WITH LOCAL AMOUNTS UP TO 4 INCHES. DUE RECENT PROLONGED DRY CONDITIONS...MAIN STEM RIVER FLOODING IS NOT EXPECTED. HOWEVER...THERE IS ENOUGH CHANCE OF URBAN/AREAL/SMALL STREAM FLOODING...ESPECIALLY WHERE STORM DRAINS ARE CLOGGED BY LEAVES AND ESSENTIALLY WHERE THERE IS MORE RUNOFF....TO WARRANT A FLOOD WATCH FROM LATE TONIGHT INTO WED AFTERNOON. LIGHT PRECIPITATION IS POSSIBLE SUNDAY INTO TUESDAY...WITH A TOTAL OF UP TO A HALF INCH EXPECTED AT THIS TIME. && .TIDES/COASTAL FLOODING... A GALE FORCE SE FLOW WILL RAPIDLY DEVELOP AHEAD OF DEEPENING LOW PRESSURE LATE TONIGHT...BEFORE VEERING TO THE S WEDNESDAY MORNING. A STORM SURGE OF 2 TO 2 1/2 FT...LOCALLY 3 FT IS EXPECTED. THE PEAK SURGE COINCIDES BEST WITH THE TIMING OF THE MORNING HIGH TIDE CYCLE IN WESTERN LONG ISLAND SOUND AND PECONIC BAY. AN ADVISORY HAS BEEN ISSUED IN THESE LOCATIONS WITH COMBINED THREAT OF STORM TIDE...WAVE SPLASH-OVER...AND HEAVY RAIN CAUSING WIDESPREAD MINOR IMPACTS. ELSEWHERE...TIMING OF PEAK SURGE AND HIGH TIDE APPEARS TO BE OFFSET...WITH ONLY LOCALIZED ISSUES EXPECTED WITH WEDNESDAY MORNING HIGH TIDE DUE TO STORM TIDE AND HEAVY RAIN. A COASTAL FLOOD STATEMENT HAS BEEN ISSUED TO ADDRESS THIS THREAT. FOR THE LATE AFTERNOON/EVENING HIGH TIDE CYCLE...WITH FLOW EXPECTED TO BEGIN TURN OFFSHORE WOULD EXPECT SURGE VALUES TO BEGIN TO FALL RAPIDLY FROM AFTERNOON ON. THE ONLY AREA TO MONITOR WOULD BE THE SOUTH SHORE BACK BAYS WITH HIGH SURF LIMITING TIDAL DRAINAGE. HIGH SURF AND MINOR EROSION ISSUES ARE EXPECTED LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT FROM BATTERING SURF OF 7-11 FT. MAIN CONCERN WILL BE THE VULNERABLE DUNES AND BREACH LOCATIONS POST SANDY. A HIGH SURF ADVISORY HAS BEEN ISSUED TO ADDRESS THIS THREAT. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR CTZ005>012. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR CTZ008-011-012. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR CTZ007-009-010. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR CTZ009-010. NY...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR NYZ067>075-078>081-176>179. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR NYZ078>081-177-179. COASTAL FLOOD ADVISORY FROM 6 AM TO 9 AM EST WEDNESDAY FOR NYZ079-081. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR NYZ071>075-176-178. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR NYZ071-073. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ067. HIGH SURF ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST WEDNESDAY NIGHT FOR NYZ080-081-178-179. NJ...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR NJZ002-004-006-103>108. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR NJZ006. MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST THURSDAY FOR ANZ330-335-338-340-345-350-353-355. && $$ SYNOPSIS...GOODMAN/MET NEAR TERM...GOODMAN/NV SHORT TERM...GOODMAN LONG TERM...MET AVIATION...SEARS MARINE...GOODMAN/MET HYDROLOGY...GOODMAN/MET TIDES/COASTAL FLOODING...NV EQUIPMENT...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
452 PM EST MON NOV 25 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF TEXAS AND LOUISIANA. LOWER CLOUDS ALREADY ENTERING THE FA FROM THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS. WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR THE TIMING. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR. WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE MOISTURE INCREASE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS THROUGH MOST OF TONIGHT THEN DETERIORATING TO IFR BY 09Z. HIGH PRESSURE ACROSS THE REGION WILL WEAKEN AND SHIFT INTO THE ATLANTIC AS LOW PRESSURE ALONG THE NORTHWEST GULF COAST SHIFTS NORTHEASTWARD. DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE APPROACHING WEATHER SYSTEM...CEILINGS HAVE ALREADY LOWERED TO AROUND 3500 FT. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z- 09Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 10Z-12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. AT THE MORE NORTHEAST TAF SITES LIKE CAE AND CUB...IFR CONDITIONS MAY BE DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO DETERIORATE RAPIDLY AT THOSE LOCATIONS WHEN THE RAIN MOVES IN. MAINLY MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
420 PM EST MON NOV 25 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...HIGH PRESSURE WILL WEAKEN THIS AFTERNOON AS A WEATHER SYSTEM DEVELOPS IN THE WESTERN GULF COAST STATES OF TEXAS AND LOUISIANA. THE UPPER RIDGE AXIS OVER THE FA WILL SHIFT EAST AND ALLOW HIGH AND MID LEVEL CLOUDS TO ENTER THE REGION FROM THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS. AFTERNOON HIGHS MAINLY IN THE MID TO UPPER 40S. A BIT WARMER IN THE CSRA AND AGS MAY HIT 51 OR 52. LIGHT MAINLY EASTERLY WINDS ARE EXPECTED. DEWPOINTS IN THE SINGLE DIGITS EARLY THIS AFTERNOON SHOULD INCREASE TO 10-15 DEGREES BY LATE AFTERNOON AS MOISTURE BEGINS TO ENTER AREA. TONIGHT...THE LATEST WATER VAPOR IMAGERY SHOWED A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR THE TIMING. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR. WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE MOISTURE INCREASE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS THROUGH MOST OF THE OVERNIGHT PERIOD THEN DETERIORATING TO IFR AROUND 09Z. HIGH PRESSURE ACROSS THE REGION WILL WEAKEN AND SHIFT INTO THE ATLANTIC AS LOW PRESSURE ALONG THE NORTHWEST GULF COAST SHIFTS NORTHEASTWARD. SCATTERED MID-HIGH LEVEL CLOUDS WILL BEGIN TO LOWER TO 10-12 KFT AND THICKEN BY 00Z THIS EVENING. WITH MOISTURE FLUX TO THE AREA AHEAD OF APPROACHING WEATHER SYSTEM TONIGHT...CEILINGS WILL CONTINUE TO LOWER TO 3-4 KFT BY 04Z-06Z TIME FRAME. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z-09Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 10Z-12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. AT THE MORE NORTHEAST TAF SITES LIKE CAE AND CUB...IFR CONDITIONS MAY BE DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO DETERIORATE RAPIDLY AT THOSE LOCATIONS WHEN THE RAIN MOVES IN. AFTER 14Z...WIDESPREAD IFR CONDITIONS AND VSBYS AT WESTERN TAF SITES OF AGS AND DNL MAY LOWER TO BELOW 1 MILE IN RAIN AT TIMES. MAINLY MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
218 PM EST MON NOV 25 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...HIGH PRESSURE WILL WEAKEN THIS AFTERNOON AS A WEATHER SYSTEM DEVELOPS IN THE WESTERN GULF COAST STATES OF TEXAS AND LOUISIANA. THE UPPER RIDGE AXIS OVER THE FA WILL SHIFT EAST AND ALLOW HIGH AND MID LEVEL CLOUDS TO ENTER THE REGION FROM THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS. AFTERNOON HIGHS MAINLY IN THE MID TO UPPER 40S. A BIT WARMER IN THE CSRA AND AGS MAY HIT 51 OR 52. LIGHT MAINLY EASTERLY WINDS ARE EXPECTED. DEWPOINTS IN THE SINGLE DIGITS EARLY THIS AFTERNOON SHOULD INCREASE TO 10-15 DEGREES BY LATE AFTERNOON AS MOISTURE BEGINS TO ENTER AREA. TONIGHT...THE LATEST WATER VAPOR IMAGERY SHOWED A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR THE TIMING. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR. WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE MOISTURE INCREASE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... HIGH PRESSURE ACROSS THE REGION WILL WEAKEN THIS AFTERNOON AS LOW PRESSURE DEVELOPS ALONG THE NORTHWEST GULF COAST THIS EVENING. VFR CONDITIONS THIS AFTERNOON THROUGH MOST OF THE OVERNIGHT PERIOD. SCATTERED MID-HIGH LEVEL CLOUDS THIS AFTERNOON WILL BEGIN TO LOWER AND THICKEN BY 00Z THIS EVENING. CEILINGS LOWERING TO 10-12 KFT. WITH MOISTURE FLUX TO THE AREA AHEAD OF APPROACHING WEATHER SYSTEM TONIGHT...CEILINGS TO CONTINUE LOWER TO 3-4 KFT BY 04Z-06Z TIME FRAME. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z-09Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 10Z-12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. AT THE MORE NORTHEAST TAF SITES LIKE CAE AND CUB...IFR CONDITIONS MAY BE DELAYED AS LONG AS 14Z BUT CONDITIONS WILL ALSO DETERIORATE RAPIDLY AS THOSE LOCATIONS WHEN THE RAIN MOVES IN. AFTER 14Z...WIDESPREAD IFR CONDITIONS AND VSBYS AT WESTERN TAF SITES OF AGS AND DNL MAY LOWER TO BELOW 1 MILE IN RAIN AT TIMES. MAINLY MODERATE RAIN ON TUESDAY BUT DUE TO INCREASING ISENTROPIC LIFT...CANNOT RULE OUT SOME HEAVY RAIN ESPECIALLY AT THE WESTERN TAF SITES. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
208 PM CST MON NOV 25 2013 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF GOING FORECAST. MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI. CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND NORTHWEST IN. A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A HALF INCH FROM ROUGHLY I-88 SOUTH. RATZER //PREV DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON. * PERIODS OF LIGHT SNOW THROUGH LATE AFTERNOON TO EARLY EVENING WITH PERIODS OF 3-4SM VIS. * OCNL SMALL AREAS OF HEAVIER SNOW WILL RIPPLE THROUGH THE GENERAL SNOW BAND DROPPING VIS TO 1-2SM FOR THE NEXT 2 HRS. * MVFR CIGS TO PERSIST UNTIL LATE TONIGHT. KREIN //DISCUSSION...UPDATED 18Z... MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS. AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA. SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS. WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO 1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS WILL QUICKLY SHIFT FROM SWLY TO NWLY. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TRENDS. * LOW TO MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED WITH WIND DRIVEN SNOW. * MEDIUM CONFIDENCE IN CIG TRENDS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 208 PM...LOW PRESSURE OVER EASTERN ONTARIO WILL MOVE INTO QUEBEC TONIGHT AS IT SLOWLY WEAKENS...ALLOWING THE GRADIENT OVER LAKE MICHIGAN TO SLOWLY RELAX WITH GALES STILL POSSIBLE EARLY THIS EVENING. SPEEDS WILL DIMINISH INTO THE 15-20KT RANGE LATER TONIGHT INTO TUESDAY MORNING. A TRAILING COLD FRONT FROM THE LOW MOVING INTO QUEBEC WILL MOVE ACROSS THE LAKE TUESDAY AFTERNOON...WITH ANOTHER WEAKER LOW DEVELOPING ALONG THE FRONT OVER LAKE SUPERIOR TONIGHT. ONCE THIS FRONT PASSES EAST OF THE LAKE...WINDS WILL SHIFT TO THE NORTHWEST AND STEADILY INCREASE AS THE GRADIENT TIGHTENS IN RESPONSE TO STRONG HIGH PRESSURE MOVE SOUTH ACROSS THE PLAINS TUESDAY AFTERNOON INTO TUESDAY NIGHT...COMBINED WITH A STRONG LOW MOVING NORTH ACROSS THE EASTERN SEABOARD. ITS POSSIBLE FOR A SHORTER PERIOD OF GALES ON THE NORTH HALF OF THE LAKE LATE TUESDAY AFTERNOON INTO TUESDAY EVENING...BUT A MORE PROLONGED PERIOD OF LOW END GALES APPEARS POSSIBLE OVER THE SOUTH HALF OF THE LAKE TUESDAY NIGHT INTO WEDNESDAY MORNING WHEN THE GRADIENT SHOULD BE THE TIGHTEST. THE LOW MOVING UP THE EAST COAST WILL CONTINUE TO DEEPEN AS IT MOVES INTO QUEBEC WEDNESDAY NIGHT WITH THE HIGH SPREADING SOUTH INTO THE SOUTHERN PLAINS AND GULF COAST STATES. A WEAKER RIDGE WILL PASS ACROSS THE LAKE WITH SPEEDS SLOWLY DIMINISHING WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. THE HIGH WILL BECOME SPRAWLING ACROSS THE EASTERN HALF OR TWO THIRDS OF THE U.S. THURSDAY NIGHT INTO FRIDAY WITH PRIMARILY WESTERLY FLOW FLOPPING AROUND SOUTHEAST FRIDAY NIGHT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
145 PM CST MON NOV 25 2013 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF GOING FORECAST. MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI. CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND NORTHWEST IN. A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A HALF INCH FROM ROUGHLY I-88 SOUTH. RATZER //PREV DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON. * PERIODS OF LIGHT SNOW THROUGH LATE AFTERNOON TO EARLY EVENING WITH PERIODS OF 3-4SM VIS. * OCNL SMALL AREAS OF HEAVIER SNOW WILL RIPPLE THROUGH THE GENERAL SNOW BAND DROPPING VIS TO 1-2SM FOR THE NEXT 2 HRS. * MVFR CIGS TO PERSIST UNTIL LATE TONIGHT. KREIN //DISCUSSION...UPDATED 18Z... MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS. AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA. SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS. WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO 1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS WILL QUICKLY SHIFT FROM SWLY TO NWLY. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TRENDS. * LOW TO MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED WITH WIND DRIVEN SNOW. * MEDIUM CONFIDENCE IN CIG TRENDS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 AM CST MON NOV 25 2013 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF GOING FORECAST. MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI. CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND NORTHWEST IN. A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A HALF INCH FROM ROUGHLY I-88 SOUTH. RATZER //PREV DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * GUSTY SOUTHWEST WINDS THROUGH LATE AFTERNOON. * PERIODS OF LIGHT SNOW THROUGH MID TO LATE AFTERNOON WITH PERIODS OF MVFR TO IFR VIS AND MVFR CIGS LIKELY. * MVFR CIGS TO PERSIST UNTIL LATE TONIGHT. KREIN //DISCUSSION...UPDATED 18Z... MAIN CONCERNS FOR THE REMAINDER OF THE AFTERNOON WILL FOCUS ON IMPACTS OF LIGHT SNOW AS WELL AS GUSTY SWLY WINDS. AT THE CURRENT TIME...A BAND OF LIGHT WARM ADVECTION SNOW IS SAGGING SWD THROUGH NRN IL AND WILL SOON MOVE INTO NWRN INDIANA. SOUTH OF THE BAND...SCT UNORGANIZED AREAS OF LIGHT SNOW ARE ALSO MOVING THROUGH THE AREA. THE LATEST RADAR TRENDS INDICATE THAT THE SNOW BAND IS BECOMING A LITTLE LESS ORGANIZED AS IT SAGS TO THE SOUTH...BUT STILL EXPECT A PERIOD OF SNOW TO IMPACT THE TERMINALS. WHILE THE SNOW IS RELATIVELY LIGHT AND ACCUMULATIONS GENERALLY NOT A MAJOR CONCERN AT THE TERMINALS...THE BIGGEST IMPACT WILL BE ON VISIBILITY DUE TO THE STRONG...GUSTY WINDS. SO...EXPECT A PERIOD OF ABOUT 2 HRS WHERE THE SNOWFALL RATE SILL BE HIGH ENOUGH...COMBINED WITH THE STRONG WINDS TO REDUCE VISIBILITY TO 1-2SM. AND THE MAIN BAND OF SNOW SAGS SOUTH OF THE TERMINALS INTO CNTRL IL/IN...THERE SHOULD STILL BE SOME LIGHT SNOW FALLING...BUT GENERALLY VISIBILITY SHOULD RETURN TO VFR LEVELS. HOWEVER...MVFR CIGS SHOULD PERSIST WELL INTO THE EVENING AND LATE NIGHT HOURS AS COOLER AIR WRAPS AROUND A DEEP LOW PRESSURE SYSTEM TRACKING THROUGH THE UPPER GREAT LAKES. WITH THE AREA BETWEEN AN APPROACHING COLD FRONT ASSOCIATED WITH THE LOW TO THE NORTH AND HIGH PRESSURE SITTING OVER THE MID ATLANTIC REGION...A SWLY GRADIENT WILL REMAIN IN PLACE UNTIL THE FRONT SWEEPS THROUGH THE REGION. LATEST MODEL GUIDANCE SUGGESTS THAT THE FRONT WILL MOVE THROUGH NRN IL/IN BY LATE TOMORROW MORNING...AT WHICH TIME WINDS WILL QUICKLY SHIFT FROM SWLY TO NWLY. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE DURATION OF MVFR AND IFR VIS ASSOCIATED WITH WIND DRIVEN SNOW. * MEDIUM TO HIGH CONFIDENCE IN CIG TRENDS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1040 AM CST MON NOV 25 2013 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE BUMPED SNOWFALL AMOUNTS JUST A BIT...TO AROUND 1 INCH...ALONG THE WI/IL STATE LINE. OTHERWISE...ONLY MINOR TWEAKS TO NEAR TERM OF GOING FORECAST. MORNING WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSIS DEPICT FAIRLY STRONG MID-LEVEL SHORT WAVE TROUGH PROPAGATING ACROSS THE UPPER MIDWEST AND NORTHERN GREAT LAKES REGION. MAIN AREA OF SURFACE LOW PRESSURE WAS NORTH OF LAKE SUPERIOR...WHILE AN AREA OF ENHANCED LOW LEVEL WARM ADVECTION WAS OCCURRING ACROSS IOWA...SOUTHEAST MINNESOTA...WISCONSIN AND FAR NORTH/NORTHWEST ILLINOIS. ISENTROPIC ASCENT AND MOISTURE ADVECTION WAS PRODUCING TOP-DOWN SATURATION IN A NARROW CORRIDOR FROM DSM-DBQ-MKE...WITH LIGHT SNOW LOWERING VISIBILITY TO 1/2 MILE IN SOME SPOTS ACROSS FAR SOUTHERN WI. CONSIDERABLE DRY AIR BELOW 800-700 MB IN DVN AND ILX 12Z...WHICH INDICATES FORCING WILL HAVE TO WORK TO SATURATE LOWER LEVELS ACROSS IL/IN TODAY. WITH STRONGEST WARM ADVECTION AND JET DYNAMICS EXPECTED TO PROVIDE THE BEST FORCING THIS MORNING...BAND OF SNOW SHOULD HAVE A HARDER TIME PRODUCING MODERATE SNOW FARTHER SOUTHEAST INTO IL AND NORTHWEST IN. A FEW REPORTS FROM NORTHEAST IA OF 3-5 INCH SNOWFALL AMOUNTS WITH INITIAL STRONG BANDING EARLY THIS MORNING...THOUGH WITH FORCING WEAKENING SOMEWHAT WITH TIME AND DRY LOW-LEVELS TO OVERCOME WOULD EXPECT AMOUNTS TO TAPER QUICKLY INTO THE LOT CWA. BASED ON RADAR TRENDS THROUGH THE MORNING...AND SOME WEB CAM IMAGERY FROM AREAS ALONG AND NORTH OF RFD-UGN WHERE A FEW TENTHS OF ACCUM ALREADY HAS OCCURRED...HAVE BUMPED SNOWFALL AMOUNTS A BIT TO AROUND AN INCH ACROSS NORTHERN PARTS OF THE NORTHERN TIER COUNTIES...TO LESS THAN A HALF INCH FROM ROUGHLY I-88 SOUTH. RATZER && .PREV DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * GUSTY SOUTHWEST WINDS TODAY. * PERIODS OF LIGHT SNOW LIKELY BEGINNING EARLY AFTERNOON THROUGH MID TO LATE AFTERNOON WITH PERIODS OF MVFR TO IFR VIS AND MVFR CIGS POSSIBLE. * HAVE PUSHED BACK TIMING OF SNOW ONSET BY AN HOUR IN THE TAFS. KREIN //DISCUSSION...UPDATED 12Z... THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG SOUTHWESTERLY WINDS. A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT. THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY. HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN WINDS. * MEDIUM CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS AND MVFR CIGS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1002 AM CST MON NOV 25 2013 .DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * GUSTY SOUTHWEST WINDS TODAY. * PERIODS OF LIGHT SNOW LIKELY BEGINNING EARLY AFTERNOON THROUGH MID TO LATE AFTERNOON WITH PERIODS OF MVFR TO IFR VIS AND MVFR CIGS POSSIBLE. * HAVE PUSHED BACK TIMING OF SNOW ONSET BY AN HOUR IN THE TAFS. KREIN //DISCUSSION...UPDATED 12Z... THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG SOUTHWESTERLY WINDS. A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT. THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY. HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN WINDS. * MEDIUM CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS AND MVFR CIGS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
804 AM CST MON NOV 25 2013 .DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * GUSTY SOUTHWEST WINDS TODAY. * PERIODS OF LIGHT SNOW LIKELY BEGINNING ARND 17 UTC THROUGH MID AFTERNOON...PERIODS OF MVFR TO IFR VIS AND MVFR CIGS POSSIBLE. KREIN //DISCUSSION...UPDATED 12Z... THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG SOUTHWESTERLY WINDS. A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT. THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY. HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN WINDS. * MEDIUM TO HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS AND MVFR CIGS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
545 AM CST MON NOV 25 2013 .DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * GUSTY SOUTHWEST WINDS TODAY. * PERIODS OF LIGHT SNOW LIKELY AFTER 16-17 UTC THROUGH MID AFTERNOON...PERIODS OF MVFR TO IFR VIS POSSIBLE. KJB //DISCUSSION...UPDATED 12Z... THE MAIN FORECAST CONCERNS THIS MORNING CONTINUE TO REVOLVE AROUND THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG SOUTHWESTERLY WINDS. A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL CONTINUE TO SUPPORT GUSTY WINDS THROUGH THE DAY. OVERALL WINDS STILL APPEAR TO BE SOUTHWESTERLY AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT. THE OTHER CONCERN IS THAT FOR LIGHT SNOW. SNOW IS BEGINNING TO FALL ACROSS PORTIONS OF IOWA AND INTO NORTHWESTERN ILLINOIS THIS MORNING. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE ACROSS NORTHEASTERN ILLINOIS AS THE LOWER LEVELS ARE STILL FAIRLY DRY. HOWEVER...WITH TIME THIS MORNING THE LOWER LEVELS WILL MOISTEN TO ALLOW SNOW TO START AFTER 16 UTC AT THE EASTERN TERMINALS AND A COUPLE HOURS SOONER AT KRFD. OVERALL...THIS WILL NOT BE A BIG SNOW MAKER. THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS UP TO A HALF INCH ARE POSSIBLE...ESPECIALLY AT KRFD. THE SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN WINDS. * MEDIUM-HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KJB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...FLURRIES IN THE EVENING WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. SUNDAY...MVFR CIGS PSBL KJB && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
323 AM CST MON NOV 25 2013 .DISCUSSION... 323 AM CST WITH NOVEMBER LOOKING TO FINISH WITH CONTINUED BELOW NORMAL TEMPERATURES DURING ITS FINAL WEEK WITH LITTLE IN THE WAY OF SHARP THERMAL CHANGES...THE PRIMARY FOCUS OF THE FORECAST WAS ON THE LIGHT SNOW EVENT TODAY AND THEN THE LAKE EFFECT SNOW POTENTIAL INTO NORTHWEST INDIANA TUESDAY NIGHT AND WEDNESDAY. SOMEWHAT SPLIT UPPER FLOW IS IN PLACE ACROSS THE CENTRAL U.S. THIS MONDAY WITH A QUICKLY-MOVING TROUGH ACROSS ONTARIO DIVING INTO THE GREAT LAKES BY AFTERNOON...AND A CLOSED LOW ACROSS THE TEXAS PANHANDLE BRINGING RARE NOVEMBER WINTER WEATHER HEADLINES TO THE SOUTHERN PLAINS. OUR FORECAST AREA BASICALLY FALLS BETWEEN THESE TWO SYSTEMS TODAY AND AS A RESULT THERE IS A VOID OF ANY OVERLY STRONG FORCING OVERHEAD. ISENTROPIC ASCENT AND SATURATION WITHIN THE WSW FLOW ALOFT THIS MORNING LOOKS TO BE THE PRIMARY CONTRIBUTOR TO PRECIPITATION GENERATION...ALTHOUGH DRY LOW-LEVELS MAY KEEP IT FLURRIES THROUGH MID TO LATE MORNING OVER CHICAGO. AN AXIS OF FRONTOGENESIS CENTERED TO THE NORTHWEST OF THE AREA FROM EASTERN IA INTO SOUTHERN WI THROUGH ~10 AM ON THE RAP AND LOCAL ARW MAY RESULT IN BETTER SNOWFALL CLIPPING THE ROCKFORD AREA THIS MORNING...AND CONCEIVABLY COULD SEE AN INCH BECAUSE OF THAT BUT THAT WOULD SEEM THE MAXIMUM. AS THE SUBTLE FORCING AND MID-LEVEL SATURATION EVOLVES EAST INTO THE AFTERNOON...PERIODS OF LIGHT SNOW WILL LIKELY RESULT IN ONE HALF INCH OR LESS FOR MOST COMMUNITIES...AND NAMELY NORTH OF I-80. WHILE NOT THE MOST IDEAL SYNOPTIC SETUP FOR FREEZING DRIZZLE...THERE ARE SOME SIGNS ON GUIDANCE THAT AS ICE INTRODUCTION IS LOST DURING THE MID TO LATE AFTERNOON THAT THERE MAY BE A BRIEF WINDOW FOR THIS. ASCENT LOOKS WEAK AND CLOUD BASES LOOK HIGH FOR THAT TO OCCUR THOUGH...SO CONTINUE TO NOT MENTION IN FORECAST. THE AMOUNT OF CLOUD COVER TODAY WILL ONLY ALLOW TEMPERATURES TO RISE BY ADVECTION...AND THAT WILL BE MEAGER AT THE SURFACE. SO MAINTAIN HIGHS MAINLY IN THE LOWER 30S...WHICH WOULD RESULT IN THE THIRD STRAIGHT DAY OF DOUBLE DIGIT DEPARTURES BELOW NORMAL. A SECOND MORE ROBUST NORTHERN STREAM WAVE...THAT ACTUALLY LOOKS TO BE A CLOSED SUB 520DM H5 LOW...WILL DROP INTO THE GREAT LAKES ON TUESDAY. A FAIRLY DEEP PV ANOMALY IS SEEN WITH THIS ALONG WITH H5 TEMPS DOWN TO NEAR -30C...WHICH COME BARRELING INTO THE FORECAST AREA BY LATE AFTERNOON INTO THE EVE TUESDAY ON THE GUIDANCE SUITE. AN ASSOCIATED SURFACE COLD FRONT LOOKS TO STEEPEN LAPSE RATES AND COULD SUPPORT SOME SNOW SHOWERS. CERTAINLY SOME FLURRIES LOOK TO BE PRESENT INTO TUESDAY NIGHT. LOWS THAT NIGHT LOOK TO RETURN TO THE MID AND POSSIBLY EVEN LOWER TEENS IN OUTLYING LOCATIONS. MORE OF A CONCERN IS TURNING TO A POTENTIAL PLOWABLE SNOW FROM LAKE EFFECT GENERATION INTO NORTHWEST INDIANA TUESDAY NIGHT INTO THE BUSIEST TRAVEL DAY OF THE YEAR ON WEDNESDAY. THERE REMAINS MODEL DIFFERENCES ON HOW QUICKLY THE AFOREMENTIONED SOUTHERN PLAINS UPPER LOW AND THIS GREAT LAKES LOW PHASE. BUT OVERALL THE FLOW ACROSS LAKE MI SHOULD BECOME STIFF AND NORTHERLY BY LATER TUESDAY NIGHT. THERE ARE EVEN SIGNS ON SOME HIGH RESOLUTION MODELS...INCLUDING OUR LOCAL ARW...OF MESO-LOW DEVELOPMENT TRANSLATING SOUTH ACROSS THE LAKE ON TUESDAY NIGHT. CONFIDENCE ON SUCH A FEATURE IS LOW AT THIS POINT...AS IS WHETHER THERE WILL EXIST A FOCUSED BAND OR JUST WIDESPREAD SHOWERS OFF THE LAKE. BUT CONFIDENCE IS HIGH THERE WILL BE AT LEAST SNOW SHOWERS INTO NORTHWEST INDIANA GIVE THE FORECAST TRAJECTORIES...STEEP LOW-LEVEL LAPSE RATES...LAKE-INDUCED CAPE OF AROUND 500 J/KG...AND EQUILIBRIUM LEVELS FORECAST AROUND 9000 FT. THESE INDICES ACTUALLY INDICATE SOMEWHERE COULD GET A ROBUST SNOW EVENT WITH HEAVY RATES WHICH WOULD IMPACT WEDNESDAY TRAVEL. IN ADDITION...USING THE CIPS ANALOGS INDICATES A FAIRLY STRONG CORRELATED EVENT FOR 850MB TEMPERATURES AND LOW-LEVEL WIND FLOW ON 11/21/08 AND THAT PRODUCED OVER 8 INCHES JUST EAST OF THE AREA. AT THIS TIME HAVE CONTINUED THE TREND OF PREVIOUS SHIFT IN INCREASING POPS ACROSS PORTER AND EASTERN LAKE COUNTIES. BEYOND THERE WAS LITTLE CHANGE TO THE FORECAST AS THE HOLIDAY ITSELF LOOKS QUIET ACROSS THE AREA WITH GRADUALLY BUILDING HEIGHTS AND SURFACE HIGH PRESSURE. A QUASI-ZONAL PATTERN IS FAVORED ON LONG RANGE DETERMINISTIC MODELS AND ENSEMBLES...WHICH WOULD FAVOR A GRADUAL MODERATION TO NEAR NORMAL FOR THE FIRST DAY OF METEOROLOGICAL WINTER ON SUNDAY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * GUSTY SOUTHWEST WINDS TODAY. * PERIODS OF LIGHT SNOW LIKELY AFTER 17 UTC THROUGH MID AFTERNOON...PERIODS OF MVFR TO IFR VIS POSSIBLE. KJB //DISCUSSION...UPDATED 06Z... THE MAIN FORECAST CONCERNS THIS MORNING REVOLVE AROUND THE LIGHT SNOW EXPECTED ACROSS THE TERMINALS TODAY...ALONG WITH THE STRONG SOUTHWESTERLY WINDS. A STRONG PRESSURE GRADIENT IS SETTING UP ACROSS THE AREA EARLY THIS MORNING IN ASSOCIATION WITH LOW PRESSURE ACROSS SOUTHERN ONTARIO AND HIGH PRESSURE ACROSS THE SOUTHEASTERN CONUS. THIS WILL SUPPORT SOME GUSTY WINDS TODAY. IN FACT...WINDS ARE ALREADY BEGINNING TO GUST UP AROUND 20 KT AT ORD EARLY THIS MORNING. OVERALL EXPECTED SOUTHWESTERLY WINDS AROUND 15 TO 17 KT WITH GUSTS UP TO 25 TO 28 KT AFTER DAYBREAK TODAY. THE OTHER CONCERN IS THAT FOR LIGHT SNOW. THESE STRONG SOUTHWEST WINDS ARE EXPECTED TO TRANSPORT JUST ENOUGH MOISTURE ACROSS THE AREA TO LEAD TO SOME LIGHT SNOW AS AN UPPER LEVEL DISTURBANCE TRACKS ACROSS SOUTHERN WISCONSIN TODAY. OVERALL...THIS WILL NOT BE A BIG SYSTEM...BUT LIGHT SNOW WILL LIKELY ONSET BY EARLY TO MID MORNING AR KRFD AND BY MID MORNING ACROSS THE EASTERN TAF SITES. ONCE IT BEGINS THERE WILL BE ABOUT A 4 TO 6 HOUR WINDOW FOR SOME LIGHT SNOW. VISIBILITIES IN THE SNOW COULD DROP DOWN AROUND 2 MILES FOR A PERIOD AND SOME LIGHT ACCUMULATIONS AROUND A HALF INCH ARE POSSIBLE. THE SNOW CHANCES WILL END QUICKLY BY MID TO LATE AFTERNOON AS DRYER AIR FILTERS IN ACROSS THE AREA. I HAVE OPTED TO REMOVE THE MENTION OF -FZDZ AS IT APPEARS THAT ALTHOUGH THE MOISTURE WILL BE VOID IN THE FAVORABLE AREAS FOR SNOW GROWTH...IT ALSO APPEARS THAT CIGS WILL BE TOO HIGH TO SUPPORT ANY PRECIP ONCE THE SNOW ENDS. KJB //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN WINDS. * MEDIUM-HIGH CONFIDENCE IN PERIODS OF LIGHT SNOW WITH MVFR TO IFR VIS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KJB //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...FLURRIES WITH MVFR CIGS LIFTING TO VFR. WEDNESDAY...LAKE EFFECT MVFR CIGS PSBL. THURSDAY AND FRIDAY...VFR. SATURDAY...MVFR CIGS PSBL OVERNIGHT. JEE && .MARINE... 206 AM CST A VERY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GREAT LAKES THROUGH MID WEEK. THE CURRENT GALE EVENT IS WELL UNDERWAY WITH SEVERAL REPORTS OF 40+ KT WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE LAKE. THESE GALES WILL CONTINUE THROUGH AT LEAST THE MID AFTERNOON HOURS TODAY AS A AN AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS SOUTHERN ONTARIO. THE WINDS WILL GRADUALLY ABATE INTO THIS EVENING. THE CURRENT GALE HEADLINE MAY BE ALOUD TO EXPIRE A FEW HOURS EARLIER THAN THE CURRENT 9 PM DEADLINE. HOWEVER...AT THIS POINT I WILL LEAVE THE HEADLINE TIMING ALONE. THE NEXT ISSUE WILL BE LATER TUESDAY THROUGH MUCH OF WEDNESDAY. A STRONG STORM SYSTEM IS EXPECTED TO MOVE UP THE EAST COAST DURING THIS TIME...AND AS HIGH PRESSURE BUILDS IN ACROSS THE MISSOURI VALLEY CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF NORTHERLY GALES UP TO 35 TO 40 KT. THIS LOOKS TO BE THE MOST PRONOUNCED ACROSS SOUTHERN LAKE MICHIGAN...AND ANY LAKE EFFECT BANDS OF SNOW THAT DEVELOP DURING THIS TIME COULD LEAD ALSO EVEN LEAD TO SOME LOCALLY HIGH WINDS IN EXCESS OF 40 KT. IT APPEARS TO BE A GOOD BET THAT A GALE HEADLINE WILL BE NEEDED DURING THIS TIME. I THREW AROUND THE IDEA OF HOSTING A GALE WATCH FOR THIS PERIOD...BUT DUE TO THE FACT IT IS STILL FAR ENOUGH OUT...I HAVE DECIDED TO LET THE CURRENT GALE HEADLINES END PRIOR TO THE ISSUANCE OF A NEW HEADLINE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1024 PM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 952 PM MST SUN NOV 24 2013 STRATUS ERODING FROM THE WEST DESPITE NO CHANGE TO WIND DIRECTION. SO EARLIER REASONING PER WHAT WAS THOUGHT CONSISTENT GUIDANCE WITH REALITY IS NOT PANNING OUT. LOVE THIS GUIDANCE. UPDATE ISSUED AT 734 PM MST SUN NOV 24 2013 JUST COMPLETED AN UPDATE. MODEL OUTPUT STILL PLAYING CATCHUP. FINALLY LOOKS LIKE TONIGHT WILL HAVE STRATUS FOR MOST IF NOT ENTIRE NIGHT ESPECIALLY EAST OF THE COLORADO BORDER. THE RUC AND GFS HAVE CAUGHT THIS IDEA VERY WELL. COMBINED THAT WITH THE HIGHER DEWPOINTS COMING IN WILL MAKE FOR MUCH WARMER MINS THAN CURRENTLY DEPICTED. NWP IS WOEFULLY TOO COOL. NEW MINS BASED ON THE RUC AND ARE WARMER. ALSO BASED ON THE RUC...INCREASED THE SKY COVER. PER AREA 00Z SOUNDINGS AND THE RUC/NAM/GFS FORECAST SOUNDINGS DECIDED TO ADD PATCHY FREEZING FOG AND DRIZZLE. MADE IT FOR THE ENTIRE NIGHT BUT LOOKS LIKE THE BEST CHANCE FOR THIS LOOKS TO BE AFTER 06Z WHEN THE WARM LAYER ALOFT BECOMES MORE ESTABLISHED. CONTINUED THE FZDZ AND FZFG THROUGH MID MORNING IN THE EAST. ADJUSTED WIND FIELD BASED ON LATEST RUC AND ADJUSTED DEWPOINTS UP PER LATEST GFS. UPDATE ISSUED AT 441 PM MST SUN NOV 24 2013 UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 104 PM MST SUN NOV 24 2013 WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS SLOWLY DIMINISHING. WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 140 PM MST SUN NOV 24 2013 THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME... GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO A WSW FLOW SAT-SUN. SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED. THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT. AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S- LOWER 50S FORECAST FOR THU-SUN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1021 PM MST SUN NOV 24 2013 STRATUS IS ERODING FROM THE WEST AND HAS MOVED EAST OF BOTH TAF SITES. SO EXPECT TREND TO CONTINUE AND VFR CONDITIONS THROUGH THE PERIOD. FRONT WILL MOVE THROUGH TOMORROW DURING THE MIDDLE OF THE DAY AND EXPECT WINDS TO BECOME GUSTY UNTIL LATE IN THE AFTERNOON. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...JRM LONG TERM...DLF AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
955 PM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 952 PM MST SUN NOV 24 2013 STRATUS ERODING FROM THE WEST DESPITE NO CHANGE TO WIND DIRECTION. SO EARLIER REASONING PER WHAT WAS THOUGHT CONSISTENT GUIDANCE WITH REALITY IS NOT PANNING OUT. LOVE THIS GUIDANCE. UPDATE ISSUED AT 734 PM MST SUN NOV 24 2013 JUST COMPLETED AN UPDATE. MODEL OUTPUT STILL PLAYING CATCHUP. FINALLY LOOKS LIKE TONIGHT WILL HAVE STRATUS FOR MOST IF NOT ENTIRE NIGHT ESPECIALLY EAST OF THE COLORADO BORDER. THE RUC AND GFS HAVE CAUGHT THIS IDEA VERY WELL. COMBINED THAT WITH THE HIGHER DEWPOINTS COMING IN WILL MAKE FOR MUCH WARMER MINS THAN CURRENTLY DEPICTED. NWP IS WOEFULLY TOO COOL. NEW MINS BASED ON THE RUC AND ARE WARMER. ALSO BASED ON THE RUC...INCREASED THE SKY COVER. PER AREA 00Z SOUNDINGS AND THE RUC/NAM/GFS FORECAST SOUNDINGS DECIDED TO ADD PATCHY FREEZING FOG AND DRIZZLE. MADE IT FOR THE ENTIRE NIGHT BUT LOOKS LIKE THE BEST CHANCE FOR THIS LOOKS TO BE AFTER 06Z WHEN THE WARM LAYER ALOFT BECOMES MORE ESTABLISHED. CONTINUED THE FZDZ AND FZFG THROUGH MID MORNING IN THE EAST. ADJUSTED WIND FIELD BASED ON LATEST RUC AND ADJUSTED DEWPOINTS UP PER LATEST GFS. UPDATE ISSUED AT 441 PM MST SUN NOV 24 2013 UPDATED FORECAST DUE TO EXPIRED WIND ADVISORY. ALSO PER DIMINISHED RADAR RETURNS REMOVED POPS FROM THE EASTERN PORTION OF THE FORECAST AREA. ALSO ADJUSTED SKY COVER PER RECENT TRENDS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 104 PM MST SUN NOV 24 2013 WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED H5 TROUGH NEARING THE FOUR CORNERS AREA. AT THE SFC...STRONG PRESSURE GRADIENT WAS IN PLACE ACROSS THE CWA WITH LOW DEEPENING OVER COLORADO AND STRONG SFC RIDGE OVER EASTERN KS AND MO. NARROW AREA OF STRONG WIND GUSTS IN EXCESS OF 40KTS...BETWEEN ITR AND GLD WAS SLOWLY DIMINISHING. WINDS SHOULD CONTINUE TO DECREASE AND FALL BELOW ADVISORY LEVELS BEFORE SUNSET AS SFC COOLING ALLOWS BOUNDARY LAYER TO DECOUPLE. A FEW LINGERING SNOW SHOWERS...WHICH LOOK LIKE THEY ARE BEING DRIVEN BY ELEVATED CI WILL MOVE OUT OF THE AREA BY EARLY EVENING AS POCKET OF DRY AIR SETTLES OVER THE AREA. UPPER LOW WILL NEAR THE AREA TONIGHT AND WITH WEAK LIFT AND LOW STABILITY COULD SEE A SHOWER OR TWO REDEVELOP AS IT PASSES. PROBABILITIES FROM ENSEMBLES ARE VERY LOW AND GIVEN MUCH DRIER AIR MOVING INTO THE AREA...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ATTM. WINDS WILL DECREASE AND BECOME LIGHT TONIGHT PRIOR TO FRONTAL PASSAGE THAT WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS. WINDS ARE NOT EXPECTED TO BE AS STRONG AS TODAY THOUGH. WITH A PERIOD OF LIGHT WINDS AND SOME POTENTIAL THINNING OF THE HIGH CLOUDS HAVE LOWERED MIN TEMPS SEVERAL DEGREES...ESPECIALLY ACROSS SOUTHERN CWA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 140 PM MST SUN NOV 24 2013 THE LARGE UPPER LOW OVER THE SOUTHWESTERN STATES WILL FINALLY MOVE AWAY FROM THE FORECAST AREA BY THE START OF THE EXTENDED PERIOD. NUMERICAL GUIDANCE INDICATES A FAST NORTHWEST FLOW ALOFT WILL SET UP OVER THE N-C PLAINS STATES IN THE TUE-WED TIME FRAME... GRADUALLY TRANSITIONING TO A BROAD RIDGE THU-FRI...AND FINALLY TO A WSW FLOW SAT-SUN. SEVERAL FAST-MOVING SHORT WAVE TROUGHS WILL MOVE THROUGH THE NORTHWEST FLOW EARLY IN THE PERIOD...IMPACTING MAINLY THE NORTHERN PLAINS AND GREAT LAKES. THE FORECAST AREA WILL EXPERIENCE SEVERAL COLD FRONTAL PASSAGES ASSOCIATED WITH THESE UPPER TROUGHS...BUT NO PRECIPITATION AND LITTLE IN THE WAY OF CLOUDS IS ANTICIPATED. THE FIRST COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WHICH WILL BRING DOWN A FAIRLY COLD CANADIAN AIR MASS TUESDAY WHICH MOVES OUT WEDNESDAY. AFTERNOON TEMPERATURES WILL BE 8-12 DEGREES BELOW NORMAL AS A RESULT TUE-WED WITH HIGHS 35-45F. PREFERRED AN SREF SOLUTION FOR TEMPS DURING THIS PERIOD. A SECOND WEAKER COLD FRONT WILL BRUSH THE AREA EARLY THURSDAY WITH MINIMAL IMPACT. AS THE UPPER FLOW TRANSITIONS TO A BROAD RIDGE LATER IN THE WEEK...HIGH TEMPERATURES WILL RETURN TO NORMAL WITH MID 40S- LOWER 50S FORECAST FOR THU-SUN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 441 PM MST SUN NOV 24 2013 MODEL PROBLEMS RESOLVING THE SNOW FIELD/BOUNDARY LAYER MOISTURE MAKE THIS A LITTLE TRICKY TAF FORECAST. CURRENTLY AT KGLD WE ARE HAVING MVFR CEILINGS AND LOOKING UPSTREAM THESE COULD CONTINUE FOR A WHILE. CURRENT CONDITIONS ARE BETWEEN THE MORE PESSIMISTIC NAM AND THE MAV WHICH IS SHOWING NOTHING. RUC IS RATHER AGGRESSIVE IN RETURNING BOUNDARY LAYER MOISTURE THIS EVENING. NAM AND RUC HAVE BEEN THE MOST AGGRESSIVE AND WRONG MODELS THE LAST FEW DAYS WITH THE GFS BETTER BUT ALSO OVERDOING IT SOME. SO FOR KGLD WILL GO WITH A PERSISTENCE FORECAST THROUGH THE EVENING WITH THE MVFR CONDITIONS AND WATCH THE TRENDS. WILL KEEP VFR AT KMCK FOR NOW THROUGH THE PERIOD. IF MORE MOIST MODELS ARE RIGHT WILL NEED MORE STRATUS AND MAYBE SOME FOG. SOUTH WINDS WILL LOSE THEIR GUSTINESS IN THE NEXT HOUR OR TWO. THEN WILL BE LIGHT AND VARIABLE UNTIL A PREFRONTAL TROUGH/COLD FRONT MOVE THROUGH LATER TONIGHT INTO TOMORROW WHICH WILL MAKE FOR STRONG AND GUSTY WINDS DURING THE DAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...JRM LONG TERM...DLF AVIATION...BULLER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1035 PM EST TUE NOV 26 2013 .UPDATE... ISSUED AT 1035 PM EST TUE NOV 26 2013 IT LOOKS LIKE THE BULK OF THIS FIRST ROUND OF SNOW WILL WIND DOWN AFTER 06Z BEFORE UPSLOPE KICKS IN AND RENEWS THE MOISTURE AND SNOW SHOWERS WEDNESDAY MORNING. THE MODELS CONTINUE TO PLAY CATCH-UP WITH REALITY AS THE LATEST NAM12 AT 00Z IS STILL INSISTING ON A DECENT 1 TO 2 INCH BAND OF SNOW OVER MUCH OF THE AREA BETWEEN NOW AND MIDNIGHT. OTHER THAN THAT...THE REST OF THE EVENT WILL LIKELY BE MORE ELEVATIONALLY AND UPSLOPE DRIVEN. ACCORDINGLY HAVE LOWERED AMOUNTS FOR ALL BUT THE HIGHER ELEVATIONS IN THE EAST WITH THIS UPDATE. WILL HOLD ON TO THE CURRENT ARRANGEMENT OF ADVISORIES AND WARNINGS... THOUGH. REPORTS OF A PILE UP ON INTERSTATE 75 IN WHITLEY COUNTY POINTS OUT THAT IT DOESN/T TAKE MUCH SNOW OR SLEET TO BE VERY DANGEROUS. HOWEVER...WILL UPDATE THE WSW AND ZONES TO REFLECT A GREATER SPREAD IN THE AMOUNTS BASED ON TERRAIN...LIMITING THE VALLEY AMOUNTS. LOOK FOR THESE UPDATES OVER THE NEXT 15 MINUTES OR SO. UPDATED GRIDS AND SNOW TOTAL GRAPHICS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 650 PM EST TUE NOV 26 2013 23Z SFC ANALYSIS SHOWS A DEEPENING LOW PRESSURE CENTER OVER SOUTHEAST GEORGIA. THIS SYSTEM IS NOW WRAPPING THE COLD AIR INTO EAST KENTUCKY AND AS A RESULT THE WESTERN PARTS OF ITS COMMA HEAD OF PCPN IS TRANSITIONING TO SNOW...HEAVY AT TIMES. ON WV SATELLITE...THE SOUTHERN SHORT WAVE SHOWS UP WELL AS IT PUNCHES INTO THE REGION. THIS WILL QUICKLY RENEW THE PCPN RETURNS THROUGH THIS PART OF KENTUCKY AND THE EASTERN TENNESSEE VALLEY AS THE FIRST WAVE MOVES OUT. PER THE LATEST HRRR AND 18Z NAM12 HAVE INCORPORATED THIS INTO THE FORECAST AND FINE TUNED SNOW AMOUNTS AND TIMING OF THIS WINTER EVENT THROUGH THE NIGHT...GENERALLY A BIT MORE SNOW TO THE NORTHEAST AND A ONE TO TWO HOUR FASTER CHANGEOVER HEADING EAST. THE LATEST TWEETS AND OBS INDICATE THAT THE SNOW LINE IS MOVING DEEPER INTO OUR NORTHWESTERN COUNTIES WITH ENHANCEMENTS ON RADAR SUGGESTING A QUICK INCH POSSIBLE AS THIS BAND MOVES EAST. THE UPDATED FORECAST HAS BEEN SENT TO THE NDFD AND WEB SERVERS. A ZFP UPDATE WILL FOLLOW SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 256 PM EST TUE NOV 26 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE PROGRESSION OF THE SYSTEM. SOME HEAVY RAIN HAS PROMPTED AN AREAL FLOOD ADVISORY FOR WHITLEY KNOX AND BELL COUNTIES. THE RAIN SHOULD BEGIN TO TAPER OFF A LITTLE IN THE NEXT FEW HOURS. PUT A SLIDE ON THE INTERNET TO SHOW THE PROGRESSION OF THE CHANGEOVER THIS EVENING FROM RAIN TO SNOW. FOR THE SNOW AMOUNTS...THE NEW MODEL RUNS HAD LITTLE CHANGE. THE DIFFERENCES IN THE NEW SNOW AMOUNT FORECAST WERE NOT VERY SIGNIFICANT. FEEL LIKE THE FORECAST HAS CAPTURED THE UPPER END OF THE SNOW FORECAST. ONE CONCERN IS THE COMBINATION OF THE SNOW AND THE WIND FOR TOMORROW AND TOMORROW EVENING. THIS HAS THE POTENTIAL FOR CREATING NEAR BLIZZARD CONDITIONS WITH LOW VISIBILITY DUE TO THE BLOWING SNOW. IT WILL ALSO CAUSE THE WIND CHILLS TO DIP DOWN PRETTY LOW. ANYONE TRAVELING ON WEDNESDAY NEED TO HAVE BLANKETS AND WARM COATS IN THE CAR. WITH THE NORTHERLY WINDS BEHIND THE SYSTEM... UPSLOPE WILL BE A FACTOR AT UPPER ELEVATIONS ALONG THE VIRGINIA AND TENNESSEE BORDERS. THE UPPER ELEVATIONS ABOVE 2000 FEET HAVE A POTENTIAL TO SEE SOME PRETTY SUBSTANTIAL SNOW AMOUNTS. WILL UPDATE THE CHANGE OVER FORECAST SLIDE ON THE INTERNET WITH THE FORECAST CHANGEOVER TIMES IF THE FORECAST CHANGES. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 256 PM EST TUE NOV 26 2013 UPPER LEVEL TROUGH WILL LINGER THROUGH THANKSGIVING DAY WITH A TREND TOWARDS ZONAL FLOW AS WE HEAD INTO THE WEEKEND. THIS WILL YIELD A COLD THANKSGIVING DAY...WITH A SLOW WARMING TREND INTO THE WEEKEND. HIGH PRESSURE WILL SKIRT ACROSS THE AREA FROM THURSDAY THROUGH SATURDAY...PROVIDING A QUIET STRETCH OF WEATHER FOR A GOOD CHUNK OF THE HOLIDAY WEEKEND. A FAST MOVING SHORTWAVE WILL PUSH EAST ACROSS THE AREA LATE IN THE WEEKEND...PRODUCING A SMALL CHANCE FOR RAIN. A STRONGER SOUTHERN STREAM WAVE WILL PUSH SOUTH OF THE AREA MONDAY INTO MONDAY NIGHT...PRODUCING A BETTER CHANCE FOR SOME RAIN. OVERALL...MODELS ARE IN PRETTY DECENT AGREEMENT...SO CONFIDENCE IS DECENT WELL INTO THE EXTENDED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 700 PM EST TUE NOV 26 2013 EXPECT WIDESPREAD IFR/LIFR CEILINGS AND VISIBILITIES THROUGH MOST OF THE PERIOD...AS A STRONG STORM SYSTEM SPREADS RAIN AND THEN SNOW ACROSS THE AREA. RAIN WILL CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THIS EVENING...WITH SNOW CONTINUING INTO WEDNESDAY. CONDITIONS WILL IMPROVE AFTER 12Z FOR MOST SITES AS THE SYSTEM MOVES OUT TO THE EAST. HOWEVER...EASTERN LOCATIONS LIKE JKL AND SJS WILL CONTINUE TO SEE LOWER VIS AND CIGS THROUGH THE DAY WEDNESDAY AS THE SNOW BECOMES MORE UPSLOPE DRIVEN. WINDS WILL BE BRISK OUT OF THE NORTHWEST AT 10 TO 20 KTS THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST WEDNESDAY FOR KYZ044- 050>052-058>060-069-080-085-086-104-106>109-111-112-114-116. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR KYZ068-079- 083-084. WINTER STORM WARNING UNTIL 7 PM EST WEDNESDAY FOR KYZ087-088-110- 113-115-117>120. && $$ UPDATE...GREIF SHORT TERM...JJ LONG TERM...KAS AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
700 PM EST TUE NOV 26 2013 .UPDATE... ISSUED AT 650 PM EST TUE NOV 26 2013 23Z SFC ANALYSIS SHOWS A DEEPENING LOW PRESSURE CENTER OVER SOUTHEAST GEORGIA. THIS SYSTEM IS NOW WRAPPING THE COLD AIR INTO EAST KENTUCKY AND AS A RESULT THE WESTERN PARTS OF ITS COMMA HEAD OF PCPN IS TRANSITIONING TO SNOW...HEAVY AT TIMES. ON WV SATELLITE...THE SOUTHERN SHORT WAVE SHOWS UP WELL AS IT PUNCHES INTO THE REGION. THIS WILL QUICKLY RENEW THE PCPN RETURNS THROUGH THIS PART OF KENTUCKY AND THE EASTERN TENNESSEE VALLEY AS THE FIRST WAVE MOVES OUT. PER THE LATEST HRRR AND 18Z NAM12 HAVE INCORPORATED THIS INTO THE FORECAST AND FINE TUNED SNOW AMOUNTS AND TIMING OF THIS WINTER EVENT THROUGH THE NIGHT...GENERALLY A BIT MORE SNOW TO THE NORTHEAST AND A ONE TO TWO HOUR FASTER CHANGEOVER HEADING EAST. THE LATEST TWEETS AND OBS INDICATE THAT THE SNOW LINE IS MOVING DEEPER INTO OUR NORTHWESTERN COUNTIES WITH ENHANCEMENTS ON RADAR SUGGESTING A QUICK INCH POSSIBLE AS THIS BAND MOVES EAST. THE UPDATED FORECAST HAS BEEN SENT TO THE NDFD AND WEB SERVERS. A ZFP UPDATE WILL FOLLOW SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 256 PM EST TUE NOV 26 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE PROGRESSION OF THE SYSTEM. SOME HEAVY RAIN HAS PROMPTED AN AREAL FLOOD ADVISORY FOR WHITLEY KNOX AND BELL COUNTIES. THE RAIN SHOULD BEGIN TO TAPER OFF A LITTLE IN THE NEXT FEW HOURS. PUT A SLIDE ON THE INTERNET TO SHOW THE PROGRESSION OF THE CHANGEOVER THIS EVENING FROM RAIN TO SNOW. FOR THE SNOW AMOUNTS...THE NEW MODEL RUNS HAD LITTLE CHANGE. THE DIFFERENCES IN THE NEW SNOW AMOUNT FORECAST WERE NOT VERY SIGNIFICANT. FEEL LIKE THE FORECAST HAS CAPTURED THE UPPER END OF THE SNOW FORECAST. ONE CONCERN IS THE COMBINATION OF THE SNOW AND THE WIND FOR TOMORROW AND TOMORROW EVENING. THIS HAS THE POTENTIAL FOR CREATING NEAR BLIZZARD CONDITIONS WITH LOW VISIBILITY DUE TO THE BLOWING SNOW. IT WILL ALSO CAUSE THE WIND CHILLS TO DIP DOWN PRETTY LOW. ANYONE TRAVELING ON WEDNESDAY NEED TO HAVE BLANKETS AND WARM COATS IN THE CAR. WITH THE NORTHERLY WINDS BEHIND THE SYSTEM... UPSLOPE WILL BE A FACTOR AT UPPER ELEVATIONS ALONG THE VIRGINIA AND TENNESSEE BORDERS. THE UPPER ELEVATIONS ABOVE 2000 FEET HAVE A POTENTIAL TO SEE SOME PRETTY SUBSTANTIAL SNOW AMOUNTS. WILL UPDATE THE CHANGE OVER FORECAST SLIDE ON THE INTERNET WITH THE FORECAST CHANGEOVER TIMES IF THE FORECAST CHANGES. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 256 PM EST TUE NOV 26 2013 UPPER LEVEL TROUGH WILL LINGER THROUGH THANKSGIVING DAY WITH A TREND TOWARDS ZONAL FLOW AS WE HEAD INTO THE WEEKEND. THIS WILL YIELD A COLD THANKSGIVING DAY...WITH A SLOW WARMING TREND INTO THE WEEKEND. HIGH PRESSURE WILL SKIRT ACROSS THE AREA FROM THURSDAY THROUGH SATURDAY...PROVIDING A QUIET STRETCH OF WEATHER FOR A GOOD CHUNK OF THE HOLIDAY WEEKEND. A FAST MOVING SHORTWAVE WILL PUSH EAST ACROSS THE AREA LATE IN THE WEEKEND...PRODUCING A SMALL CHANCE FOR RAIN. A STRONGER SOUTHERN STREAM WAVE WILL PUSH SOUTH OF THE AREA MONDAY INTO MONDAY NIGHT...PRODUCING A BETTER CHANCE FOR SOME RAIN. OVERALL...MODELS ARE IN PRETTY DECENT AGREEMENT...SO CONFIDENCE IS DECENT WELL INTO THE EXTENDED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 700 PM EST TUE NOV 26 2013 EXPECT WIDESPREAD IFR/LIFR CEILINGS AND VISIBILITIES THROUGH MOST OF THE PERIOD...AS A STRONG STORM SYSTEM SPREADS RAIN AND THEN SNOW ACROSS THE AREA. RAIN WILL CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THIS EVENING...WITH SNOW CONTINUING INTO WEDNESDAY. CONDITIONS WILL IMPROVE AFTER 12Z FOR MOST SITES AS THE SYSTEM MOVES OUT TO THE EAST. HOWEVER...EASTERN LOCATIONS LIKE JKL AND SJS WILL CONTINUE TO SEE LOWER VIS AND CIGS THROUGH THE DAY WEDNESDAY AS THE SNOW BECOMES MORE UPSLOPE DRIVEN. WINDS WILL BE BRISK OUT OF THE NORTHWEST AT 10 TO 20 KTS THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST WEDNESDAY FOR KYZ044- 050>052-058>060-069-080-085-086-104-106>109-111-112-114-116. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR KYZ068-079- 083-084. WINTER STORM WARNING UNTIL 7 PM EST WEDNESDAY FOR KYZ087-088-110- 113-115-117>120. && $$ UPDATE...GREIF SHORT TERM...JJ LONG TERM...KAS AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1034 PM EST TUE NOV 26 2013 .UPDATE... ISSUED AT 1034 PM EST TUE NOV 26 2013 MAIN FCST CONCERNS OVERNIGHT ARE HEADLINES AND LES TRENDS. WITH KDLH RADAR SHOWING LES BANDS STREAMING INTO FAR WRN UPPER MI TOWARD THE KIWD AREA...SNOW LIKELY HAS HAS BEEN FAIRLY HVY IN THAT AREA THIS EVENING. BANDS HAVE BEEN MOVING THOUGH...PREVENTING MORE SUBSTANTIAL ACCUMULATION. OVER ERN LAKE SUPERIOR...LES HAS BECOME MORE WIDESPREAD WITH A GENERAL UPTICK IN INTENSITY UNDER STRONGER LOW-LEVEL CONVERGENCE ALONG SOUTHWARD MOVING SFC TROF. HOWEVER... WITH SHORTWAVE TROF NOW SLIPPING E OF LAKE SUPERIOR PER WATER VAPOR IMAGERY...HAVE CONCERN THAT SNOW ACCUMULATIONS NEED TO BE TONED DOWN ACROSS THE BOARD OVERNIGHT/WED MORNING AS MODEL GUIDANCE SHOWS RATHER HEALTHY LARGE SCALE QVECTOR DIVERGENCE DOMINATING THRU WED MORNING BEHIND WAVE. SO...APART FROM LOCALIZED LOW-LEVEL CONVERGENCE/UPSLOPE TERRAIN ENHANCEMENT...LES MAY MOSTLY BE ON THE LIGHTER SIDE. ON THE PLUS SIDES...DGZ SHOULD BE FAIRLY WELL CENTERED WITHIN THE UPWARD MOTION ZONE TO FLUFF UP SNOW ACCUMULATIONS...AND UPSTREAM 00Z CWPL SOUNDING SHOWED A DEEP MOISTURE PROFILE THRU ABOUT 11KFT OR SO. HOWEVER...GIVEN THE LARGE SCALE NEGATIVES...GENERALLY LOWERED SNOW ACCUMULATIONS FROM THIS POINT FORWARD. THE WARNING FOR MARQUETTE COUNTY MAY BE TOUGH TO ACHIEVE. IF ANY PLACE DOES REACH WARNING CRITERIA...IT WILL PROBABLY BE THE HIGHER TERRAIN N AND NW OF NEGAUNEE WHERE UPSLOPE IS MAXIMIZED. ADVY IS PRETTY MARGINAL FOR THE KEWEENAW OVERNIGHT WITH WINDS BECOMING A LESS FAVORABLE NORTHERLY DIRECTION. STILL MAY SEE A FEW HEAVIER SNOW BANDS TRAVERSE THE KEWEENAW...AND GUSTY WINDS...MAINLY ALONG THE LAKE...WILL LEAD TO BLSN. OVER THE FAR W...PRECONDITIONING FROM LAKE NIPIGON MAY STILL FAVOR MORE PERSISTENT HEAVIER SNOW...MAINLY FROM THE PORCUPINE MTNS TO KIWD VCNTY AS THE NIGHT WEARS ON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 505 PM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON. AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED 8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES. EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7 INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4 OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES WARNING FOR TONIGHT THROUGH WEDNESDAY. FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA. INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER OFF WED AFTERNOON FROM WEST TO EAST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 416 PM EST TUE NOV 26 2013 UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST LOCATIONS. THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT THINKING REMAINS. OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER 20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE DISTURBANCE. EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE 30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 642 PM EST TUE NOV 26 2013 PASSAGE OF A DISTURBANCE AND ASSOCIATED SFC TROF WILL BRING LAKE EFFECT SNOW SHOWERS TO KIWD/KCMX/KSAW THRU MUCH IF NOT ALL OF THIS FCST PERIOD. AS IS TYPICAL FOR LAKE EFFECT...CONDITIONS WILL LIKELY VARY CONSIDERABLY (FROM VFR TO AS LOW AS LIFR) AT ALL TERMINALS TONIGHT/WED MORNING. AT KIWD...ENHANCED LOW-LEVEL CONVERGENCE SHOULD GENERALLY RESULT IN IFR CONDITIONS FALLING TO LIFR THIS EVENING. ARRIVAL OF DRIER AIR AND MORE ANTICYCLONIC FLOW LATE WED MORNING/AFTN WILL RESULT IN IMPROVING CONDITIONS TO IFR THEN MVFR. AT KCMX... DEVELOPING NRLY FLOW BEHIND TROF WILL NOT BE AS FAVORABLE FOR PERSISTENT LOW CONDITIONS. MUCH OF THE NIGHT SHOULD SEE CONDITIONS VARYING BTWN IFR AND MVFR WITH MVFR PROBABLY PREVAILING WED. AT KSAW...INITIAL VFR CONDITIONS WILL DROP RAPIDLY TO IFR AS WINDS SHIFT NORTHERLY AND HEAVIER SNOW SHOWERS ARRIVE 04-06Z. IMPROVEMENT TO IFR THEN MVFR WILL OCCUR WED AFTN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST TUE NOV 26 2013 WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE 2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR. LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER MAINLY E LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004- 006. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005. LAKE SUPERIOR... GALE WARNING UNTIL 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING UNTIL 10 AM EST WEDNESDAY FOR LSZ265. GALE WARNING UNTIL 5 AM EST WEDNESDAY FOR LSZ264. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...VOSS LONG TERM...KF AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 PM EST TUE NOV 26 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 505 PM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON. AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED 8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES. EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7 INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4 OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES WARNING FOR TONIGHT THROUGH WEDNESDAY. FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA. INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER OFF WED AFTERNOON FROM WEST TO EAST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 416 PM EST TUE NOV 26 2013 UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST LOCATIONS. THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT THINKING REMAINS. OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER 20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE DISTURBANCE. EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE 30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 642 PM EST TUE NOV 26 2013 PASSAGE OF A DISTURBANCE AND ASSOCIATED SFC TROF WILL BRING LAKE EFFECT SNOW SHOWERS TO KIWD/KCMX/KSAW THRU MUCH IF NOT ALL OF THIS FCST PERIOD. AS IS TYPICAL FOR LAKE EFFECT...CONDITIONS WILL LIKELY VARY CONSIDERABLY (FROM VFR TO AS LOW AS LIFR) AT ALL TERMINALS TONIGHT/WED MORNING. AT KIWD...ENHANCED LOW-LEVEL CONVERGENCE SHOULD GENERALLY RESULT IN IFR CONDITIONS FALLING TO LIFR THIS EVENING. ARRIVAL OF DRIER AIR AND MORE ANTICYCLONIC FLOW LATE WED MORNING/AFTN WILL RESULT IN IMPROVING CONDITIONS TO IFR THEN MVFR. AT KCMX... DEVELOPING NRLY FLOW BEHIND TROF WILL NOT BE AS FAVORABLE FOR PERSISTENT LOW CONDITIONS. MUCH OF THE NIGHT SHOULD SEE CONDITIONS VARYING BTWN IFR AND MVFR WITH MVFR PROBABLY PREVAILING WED. AT KSAW...INITIAL VFR CONDITIONS WILL DROP RAPIDLY TO IFR AS WINDS SHIFT NORTHERLY AND HEAVIER SNOW SHOWERS ARRIVE 04-06Z. IMPROVEMENT TO IFR THEN MVFR WILL OCCUR WED AFTN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST TUE NOV 26 2013 WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE 2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR. LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER MAINLY E LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004- 006. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084. LAKE SUPERIOR... GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST WEDNESDAY FOR LSZ265. GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST WEDNESDAY FOR LSZ264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1257 PM EST MON NOV 25 2013 .SYNOPSIS... ISSUED AT 449 AM EST MON NOV 25 2013 WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND. && .UPDATE... ISSUED AT 1239 PM EST MON NOV 25 2013 AS EARLIER ANTICIPATED...DEEPER MOISTURE IS IN THE PROCESS OF EXITING THE AREA...AND THIS HAS CAUSED SNOW SHOWER ACTIVITY TO DIMINISH QUITE RAPIDLY PAST 1-2 HRS. IN GENERAL...1-3 INCHES OF SNOW HAS FALLEN THUS FAR ACROSS NW LOWER AND PARTS OF ERN UPPER. GIVEN MODEST OVER-WATER INSTABILITY...DON/T EXPECT MUCH MORE THAN SCATTERED SNOW SHOWERS /WITH LITTLE NEW ACCUMULATION/ UNTIL MOISTURE DEEPENS BACK UP A BIT EARLY THIS EVENING. WILL UPDATE FORECAST TO REFLECT THIS TREND. SOME CONCERN THAT SHALLOWING MOISTURE PROFILE (TO WARMER THAN ABOUT -8C) MAY SUPPORT SOME DRIZZLE OR FREEZING DRIZZLE THIS AFTERNOON (DEPENDING ON LOCATION AND SURFACE TEMPERATURE). SOME OBS ALONG THE LAKE MICHIGAN SHORELINE ARE SHOWING MVFR VSBYS WITHOUT SNOW BEING REPORTED. 88D ALSO SHOWING A BROADENING AREA OF WEAK RADAR RETURNS - POSSIBLY INDICATIVE OF DRIZZLE. WILL MONITOR FOR THIS POTENTIAL WEATHER/HAZARD. UPDATE ISSUED AT 930 AM EST MON NOV 25 2013 QUICK SHOT OF LAKE ENHANCED SNOW CONTINUES TO IMPACT EAST UPPER AND NW LOWER THIS MORNING...AS SHORT WAVE AND ASSOCIATED DEEP MOISTURE SWINGS THROUGH THE REGION. OVERALL LAKE CONTRIBUTION NOT GREAT...WITH WATER TEMPS NEAR +8C AND 850 MB TEMPS AROUND -6C (IDEA FURTHER SUPPORTED BY 12Z APX/GRB SOUNDINGS). THAT SAID...COMBINATION OF ONGOING SNOW BURST AND CONTINUED GUSTY WINDS WILL STILL RESULT IN NEAR-ADVISORY CONDITIONS NEXT SEVERAL HOURS WITH LOCALLY DIFFICULT TRAVEL. HOWEVER...AS DEEPER MOISTURE DEPARTS AND ONLY MARGINAL LAKE CONTRIBUTIONS LINGER...SUSPECT A MARKED DECREASE IN SNOW SHOWER INTENSITY EARLY THIS AFTERNOON. FOR THIS REASON...EXPECT 2-4 INCH SNOW AMOUNTS /MAINLY NW LOWER/ TO HOLD FOR THE DAY. UPDATE ISSUED AT 629 AM EST MON NOV 25 2013 DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR DESTINATION. DID INCREASE SNOWFALL ACROSS AN AREAS SURROUNDING LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS ARE EXPECTED THIS MORNING. OTHERWISE...THE FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 449 AM EST MON NOV 25 2013 WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER. NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH ALONG THE LAKE MICHIGAN SHORE. THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND -6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW. THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM). WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON. HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EST MON NOV 25 2013 A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND. TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND. WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO -11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS TO OUT OF THE NNW INTO TUESDAY EVENING. THE MOST IMPRESSIVE LES PARAMETERS ARE REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT. HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE MICHIGAN. THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY. FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE LOWER HALF OF THE 30S OVER THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1250 PM EST MON NOV 25 2013 LOW LEVEL MOISTURE WILL REMAIN WIDESPREAD THROUGH TUESDAY...WITH PRIMARILY MVFR CEILINGS ACROSS NW LOWER MI (TVC/PLN/MBL)...AND VFR CEILINGS NE LOWER MI (APN). THERE MAY BE A BRIEF PERIOD OF HIGHER (VFR) CEILINGS TONIGHT...BUT NOT A HIGH CONFIDENCE OCCURRENCE. OTHERWISE...SCATTERED SNOW SHOWERS WILL PERSIST DOWNWIND OF LAKE MICHIGAN THROUGH TUESDAY. THE NEXT INCREASE IN LAKE SNOW IS EXPECTED MIDDAY TUESDAY...AS COLDER AIR SWEEPS EWD ACROSS LAKE MICHIGAN. WINDS WILL REMAIN BRISK FROM THE SOUTHWEST. && .MARINE... ISSUED AT 449 AM EST MON NOV 25 2013 A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS. THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT... BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019- 020-025-031. LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322. && $$ UPDATE...BS SYNOPSIS...DL SHORT TERM...DL LONG TERM...SD AVIATION...BS MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1200 PM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1200 PM EST MON NOV 25 2013 AS A STRONG DISTURBANCE OVER ONTARIO AND ITS ATTENDANT SFC COLD FRONT DIGS SE INTO THE AREA...EXPECT MVFR CIGS AT IWD AND CMX THROUGH THIS PERIOD WITH LAKE EFFECT SNOW SHOWERS CONTINUING. AS WINDS GET MORE NORTHERLY WITH TIME...BOTH SITES WILL GO TO IFR VIS IN THE HEAVIER SNOW SHOWERS STARTING FIRST AT CMX BY THIS EVENING AND BY TUE MORNING AT IWD. AT SAW...MVFR CIGS WILL MOVE OUT THIS AFTERNOON WITH A DOWNSLOPE WIND HELPING TO RAISE CIGS TO LOW VFR. WITH A WEST WIND AT SAW THIS EVENING THROUGH TUE MORNING...MVFR CONDITIONS WILL SET UP WITH SOME SNOW SHOWERS MOVING IN THIS EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST MON NOV 25 2013 SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY. NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
942 AM EST MON NOV 25 2013 .SYNOPSIS... ISSUED AT 449 AM EST MON NOV 25 2013 WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND. && .UPDATE... ISSUED AT 930 AM EST MON NOV 25 2013 QUICK SHOT OF LAKE ENHANCED SNOW CONTINUES TO IMPACT EAST UPPER AND NW LOWER THIS MORNING...AS SHORT WAVE AND ASSOCIATED DEEP MOISTURE SWINGS THROUGH THE REGION. OVERALL LAKE CONTRIBUTION NOT GREAT...WITH WATER TEMPS NEAR +8C AND 850 MB TEMPS AROUND -6C (IDEA FURTHER SUPPORTED BY 12Z APX/GRB SOUNDINGS). THAT SAID...COMBINATION OF ONGOING SNOW BURST AND CONTINUED GUSTY WINDS WILL STILL RESULT IN NEAR-ADVISORY CONDITIONS NEXT SEVERAL HOURS WITH LOCALLY DIFFICULT TRAVEL. HOWEVER...AS DEEPER MOISTURE DEPARTS AND ONLY MARGINAL LAKE CONTRIBUTIONS LINGER...SUSPECT A MARKED DECREASE IN SNOW SHOWER INTENSITY EARLY THIS AFTERNOON. FOR THIS REASON...EXPECT 2-4 INCH SNOW AMOUNTS /MAINLY NW LOWER/ TO HOLD FOR THE DAY. UPDATE ISSUED AT 629 AM EST MON NOV 25 2013 DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR DESTINATION. DID INCREASE SNOWFALL ACROSS AN AREAS SURROUNDING LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS ARE EXPECTED THIS MORNING. OTHERWISE...THE FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 449 AM EST MON NOV 25 2013 WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER. NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH ALONG THE LAKE MICHIGAN SHORE. THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND -6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW. THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM). WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON. HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EST MON NOV 25 2013 A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND. TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND. WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO -11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT. HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE MICHIGAN. THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY. FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE LOWER HALF OF THE 30S OVER THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 629 AM EST MON NOV 25 2013 HIGH LEVEL OF CONCERN THIS MORNING FOR THE AVIATION COMMUNITY. A BAND OF MODERATE TO HEAVY SNOWFALL WILL ENTER INTO THE NW LOWER AIRPORTS STARTING WITH PLN AT THE START OF THE TAF PERIOD...AND REACHING TVC/MBL A FEW HOURS LATER. THIS BAND OF SNOW WILL RAPIDLY INTENSIFY AND INCREASE IN COVERAGE THIS MORNING...AND COMBINE WITH VERY STRONG WIND GUSTS OUT OF THE SW...MAXING OUT AT 40-50 MPH...ESPECIALLY AT MBL. THESE WINDS HAVE ALREADY SUBSTANTIALLY MIXED DOWN TO THE SFC...AND THIS MECHANICAL MIXING IS STRONG ENOUGH TO ELIMINATE ALL MENTION OF LLWS...BUT IT`S STILL BLOWING VERY HARD ALOFT. WILL BRING IN A PERIOD OF IFR AT ALL AIRPORTS EXCEPT APN...WHICH WILL LIKELY JUST SEE SOME MVFR CONDITION LATER THIS MORNING/MIDDAY. LAKE EFFECT SNOWS WILL CONTINUE THROUGH THE DAY AND NIGHT IN DEVELOPING MORE WESTERLY FLOW...WHICH DOES DECREASE THROUGH THE LATTER HALF OF THE DAY AN NIGHT. THIS PRIMARILY AFFECTS PLN WHERE MVFR CONDITIONS WILL BE THE RULE. PERIODS OF MVFR CIGS/VSBYS FOR TVC...TO A LESSER DEGREE AT MBL. SNOWS NOT GOING TO REACH APN. A QUICK 1-3 INCHES OF SNOW IS DEFINITELY POSSIBLE THIS MORNING WITH LIQUID TO SNOW RATIOS ON THE LOW END AT AROUND 10:1. OVERALL CONFIDENCE IS HIGH FOR THE EVOLUTION OF THE DESCRIBED WEATHER. && .MARINE... ISSUED AT 449 AM EST MON NOV 25 2013 A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS. THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT... BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019- 020-025-031. LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322. && $$ UPDATE...BS SYNOPSIS...DL SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
645 AM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 645 AM EST MON NOV 25 2013 AS A STRONG DISTURBANCE OVER NW ONTARIO AND ITS ATTENDANT SFC COLD FRONT DIGS SE INTO THE NRN GREAT LAKES...EXPECT MVFR CIGS TO DEVELOP OVER THE W AT IWD AND CMX THIS MORNING. WITH A STRONG UPSLOPE W WIND...THE FROPA WILL ALSO BRING MVFR VSBY FOR A COUPLE HOURS AT CMX THIS MORNING. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHANCE OF MORE PERSISTENT MVFR WX WILL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W WIND...WHICH WILL GUST AS HIGH AS 30 KTS WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE APPROACH OF ANOTHER DISTURBANCE AND LOW PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER LES TO CMX THIS EVENING...SO FCST IFR VSBYS AT THIS SITE THEN. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST MON NOV 25 2013 SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY. NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014. LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264. LAKE MICHIGAN... GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 644 AM EST MON NOV 25 2013 AS A STRONG DISTURBANCE OVER NW ONTARIO AND ITS ATTENDANT SFC COLD FRONT DIGS SE INTO THE NRN GREAT LAKES...EXPECT MVFR CIGS TO DEVELOP OVER THE W AT IWD AND CMX THIS MORNING. WITH A STRONG UPSLOPE W WIND...THE FROPA WILL ALSO BRING MVFR VSBY FOR A COUPLE HOURS AT CMX THISMORNING. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHANCE OF MORE PERSISTENT MVFR WX WILL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W WIND...WHICH WILL GUST AS HIGH AS 30 KTS WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE APPROACH OF ANOTHER DISTURBANCE AND LOW PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER LES TO CMX THIS EVENING...SO FCST IFR VSBYS AT THIS SITE THEN. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST MON NOV 25 2013 SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY. NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014. LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264. LAKE MICHIGAN... GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
630 AM EST MON NOV 25 2013 .SYNOPSIS... ISSUED AT 449 AM EST MON NOV 25 2013 WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND. && .UPDATE... ISSUED AT 629 AM EST MON NOV 25 2013 DEEP MOISTURE OUT AHEAD OF AN ADVANCING COLD FRONT IS STARTING TO DEVELOP SNOWS ACROSS FAR NRN LAKE MICHIGAN AND THROUGH THE STRAITS REGION. STILL DEFINITELY EXPECTING A RAPID PRODUCTION AND INTENSIFICATION OF SNOWS IN A SW TO NE ORIENTED BAND...COMBINED WITH VERY STRONG SW WIND GUSTS TO 50 MPH. THIS WILL BRING A PERIOD OF MODERATE TO HEAVY SNOWS ACROSS MUCH OF NW LOWER AND EASTERN SECTIONS OF CHIP/MACK COUNTIES THIS MORNING. ALREADY ISSUED THE INITIAL SPS ALERTING OF RAPIDLY DEVELOPING HAZARDOUS DRIVING CONDITIONS. FOLKS...PLEASE ALLOW EXTRA TIME TO REACH YOUR DESTINATION. HIGH PROFILE VEHICLES WILL HAVE AN EXTRA BOOST TO THE HAZARD DUE TO THE STRONG WINDS. DID INCREASE SNOWFALL ACROSS AN AREAS SURROUNDING LEELANAU COUNTY...WHERE A LONGER PERIOD OF SNOWS ARE EXPECTED THIS MORNING. OTHERWISE...THE FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 449 AM EST MON NOV 25 2013 WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER. NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH ALONG THE LAKE MICHIGAN SHORE. THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND -6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW. THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM). WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON. HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EST MON NOV 25 2013 A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND. TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND. WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO -11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT. HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE MICHIGAN. THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY. FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE LOWER HALF OF THE 30S OVER THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 629 AM EST MON NOV 25 2013 HIGH LEVEL OF CONCERN THIS MORNING FOR THE AVIATION COMMUNITY. A BAND OF MODERATE TO HEAVY SNOWFALL WILL ENTER INTO THE NW LOWER AIRPORTS STARTING WITH PLN AT THE START OF THE TAF PERIOD...AND REACHING TVC/MBL A FEW HOURS LATER. THIS BAND OF SNOW WILL RAPIDLY INTENSIFY AND INCREASE IN COVERAGE THIS MORNING...AND COMBINE WITH VERY STRONG WIND GUSTS OUT OF THE SW...MAXING OUT AT 40-50 MPH...ESPECIALLY AT MBL. THESE WINDS HAVE ALREADY SUBSTANTIALLY MIXED DOWN TO THE SFC...AND THIS MECHANICAL MIXING IS STRONG ENOUGH TO ELIMINATE ALL MENTION OF LLWS...BUT IT`S STILL BLOWING VERY HARD ALOFT. WILL BRING IN A PERIOD OF IFR AT ALL AIRPORTS EXCEPT APN...WHICH WILL LIKELY JUST SEE SOME MVFR CONDITION LATER THIS MORNING/MIDDAY. LAKE EFFECT SNOWS WILL CONTINUE THROUGH THE DAY AND NIGHT IN DEVELOPING MORE WESTERLY FLOW...WHICH DOES DECREASE THROUGH THE LATTER HALF OF THE DAY AN NIGHT. THIS PRIMARILY AFFECTS PLN WHERE MVFR CONDITIONS WILL BE THE RULE. PERIODS OF MVFR CIGS/VSBYS FOR TVC...TO A LESSER DEGREE AT MBL. SNOWS NOT GOING TO REACH APN. A QUICK 1-3 INCHES OF SNOW IS DEFINITELY POSSIBLE THIS MORNING WITH LIQUID TO SNOW RATIOS ON THE LOW END AT AROUND 10:1. OVERALL CONFIDENCE IS HIGH FOR THE EVOLUTION OF THE DESCRIBED WEATHER. && .MARINE... ISSUED AT 449 AM EST MON NOV 25 2013 A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS. THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT... BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019- 020-025-031. LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322. && $$ UPDATE...SD SYNOPSIS...DL SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY MORNING) ISSUED AT 520 AM EST MON NOV 25 2013 A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR MI EARLY THIS MRNG...SO EXPECT VFR CONDITIONS DESPITE QUITE A BIT OF MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR LK WINNIPEG AND ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR LKS...EXPECT MVFR CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY SUNRISE. WITH A STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR CONDITIONS FOR A COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHC OF MORE PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED LOCATION WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE APRCH OF ANOTHER DISTURBANCE/LO PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER LES TO CMX THIS EVNG...SO FCST IFR VSBYS AT THIS SITE THEN. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST MON NOV 25 2013 SW TO W GALES OVER LAKE SUPERIOR THIS MORNING ARE EXPECTED TO DIMINISH BY LATE MORNING OVER THE WEST AND MID AFTERNOON OVER THE EAST. THE PRES GRADIENT WILL WEAKEN AS A TROUGH MOVES THROUGH THE LAKE AND LOW PRESSURE NORTH OF LAKE SUPERIOR MOVES TOWARD JAMES BAY. NORTHWEST WINDS TO 25 KTS SHIFT TO THE NORTH TO 30 KTS LATER TUESDAY AND TUESDAY NIGHT. MAY GET CLOSE TO GALES THOUGH TUESDAY NIGHT INTO WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 25 KTS THURSDAY INTO FRIDAY AS PRESSURE GRADIENT RELAXES. NEXT PERIOD OF STRONGER WINDS WILL BE SATURDAY AS SOUTH WINDS INCREASE TO 30 KTS OVER THE EASTERN LAKE AHEAD OF STRONGER LOW PRESSURE SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014. LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264. LAKE MICHIGAN... GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
520 AM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY MORNING) ISSUED AT 520 AM EST MON NOV 25 2013 A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR MI EARLY THIS MRNG...SO EXPECT VFR CONDITIONS DESPITE QUITE A BIT OF MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR LK WINNIPEG AND ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR LKS...EXPECT MVFR CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY SUNRISE. WITH A STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR CONDITIONS FOR A COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS CONDITION WL BE MARGINAL AND MAY REMAIN VFR. THE BEST CHC OF MORE PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED LOCATION WITH A SLOW INFLUX OF COLDER AIR/MORE DESTABILIZATION. THE APRCH OF ANOTHER DISTURBANCE/LO PRES TROF MAY BRING ANOTHER ROUND OF HEAVIER LES TO CMX THIS EVNG...SO FCST IFR VSBYS AT THIS SITE THEN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 252 PM EST SUN NOV 24 2013 SW GALES EXPECTED OVER NORTH CENTRAL LAKE SUPERIOR AND THE NORTHERN LAKE MICHIGAN ZONES TONIGHT INTO MON MORNING AND WILL CONTINUE THE GALE WARNING IN LAKE SUPERIOR DUE TO CHANNELED FLOW BETWEEN THE KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO TUESDAY AND REMAIN UP TO 30 KTS. GETS CLOSE TO GALES ON LAKE SUPERIOR AGAIN TUE NIGHT INTO WED AND WILL HAVE TO WATCH THIS EVENT FOR NOW. WINDS THEN STAY BELOW 20 KNOTS FOR THE REST OF THE FORECAST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014. LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264. LAKE MICHIGAN... GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST MON NOV 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW FROM CNTRL CANADA THROUGH THE GREAT LAKES WITH ONE SHORTWAVE TROUGH FROM NW ONTARIO INTO NW MN AND ANOTHER WELL TO THE NORTH MOVING INTO NRN SASK. AT THE SFC...A TIGHT PRES GRADIENT PREVAILED ACROSS THE WRN GREAT LAKES BTWN A 1000 MB LOW LOCATED JUST NORTH OF THUNDER BAY ONTARIO AND A 1036 MB RIDGE OVER THE OH VALLEY. WITH THE STRONGEST PRES FALLS MOVING TO THE NE OF LAKE SUPERIOR...VERY STRONG SW WINDS PERSISTED ACROSS WRN LAKE SUPERIOR AND NRN LAKE MICHIGAN. WAA LEADING TO INCREASING STABILITY HAS LIMITED MIXING OF 45-50 KNOT 925-850 MB WINDS TOWARD THE SFC EXCEPT OVER THE RELATIVELY WARM LAKE MICHIGAN WATERS. GUSTS IN THE 35-40 KT RANGE PERSISTED FROM FAIRPORT TO PORT INLAND WHERE A WIND ADVISORY WAS IN EFFECT. WINDS OVER INLAND LOCATIONS AT ESC AND ISQ WERE ONLY GUSTING TO AROUND 25 KNOTS. RADAR INDICATED WEAK RETURNS...MAINLY OVER THE ERN CWA...WITH SOME PATCHY LIGHT SNOW OR FLURRIES SUPPORTED BY 700-300 QVECTOR CONV AND ISENTROPIC LIFT AHEAD OF THE UPSTREAM SHRTWV. TODAY...EXPECT WINDS TO SUBSIDE BY THE 15Z WIND ADVISORY EXPIRATION TIME AS THE CORE OF THE STRONGEST 925-850 MB WINDS SHIFTS OFF TO THE EAST. AS THE AREA OF LIGHT SNOW MOVES TO THE EAST...SOME LAKE ENHANCEMENT MAY BE POSSIBLE WITH THE SW FLOW OFF OF LAKE MICHIGAN BUT SHOULD REMAIN MAINLY TO THE SOUTH AND EAST OF THE CWA. OVER THE KEWEENAW...AN AREA OF LOW LEVEL CONV AS WINDS VEER FROM SW TO W MAY BRING A BRIEF PERIOD OF LAKE ENHANCED SNOW. HOWEVER...MID LEVEL DRYING WITH THE DRY SLOT AND MARGINAL INSTABILITY WITH 850 MB TEMPS AROUND -7C (LAKE SFC NEAR 4C) SUPPORTS ONLY CHANCE POPS WITH ANY ACCUMULATIONS ONLY AMOUNTING TO A HALF INCH OR LESS. INCREASING 850-700 MB MOISTURE AND AND 850/700 MB TEMPS DROPPING TO -10C/-17C WITH THE APPROACH OF THE SHRTWV WILL ALSO BRING AN INCREASE IN LAKE ENHANCED SNOW INTO THE WEST AND THE ERN SHORELINE FROM PICTURED ROCKS TO GRAND MARAIS. TONIGHT...STRONGER CAA DROPPING 850 MB TEMPS TO AROUND -18C BOOSTING LAKE INDUCED CAPES TO NEAR 700 J/KG ALONG WITH STRENGTHENING CYCLONIC NW FLOW WILL BRING A FURTHER INCREASE IN LES INTO THE WEST. THE HIGH RES MODELS OFFER A VARIETY OF SOLUTIONS AS TO WHERE THE HEAVIER SNOW BANDS WILL FOCUS AND DELAY THE STRONGER VEERING WIND SHIFT AND LOW LEVEL CONV BAND MOVING IN TIL AFT 12Z. ALTHOUGH SEVERAL INDICATE THE GREATER SNOW POTENTIAL INTO THE KEWEENAW AND IRONWOOD AREAS...CONFIDENCE IN IN HIGHLIGHTING ANY PARTICULAR LOCATION IS LIMITED. SO...A GENERAL 2 TO 5 INCH FCST WAS INCLUDED FOR MOST OF THE NW TO WNW FLOW SNOWBELTS IN THE WEST AS WELL AS LOCATIONS NORTH OF M-28 EAST OF MUNISING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 437 AM EST MON NOV 25 2013 EXTENT OF LAKE EFFECT SNOW AND SNOW AMOUNTS ALONG WITH THE NEED FOR ANY ADVISORIES OR WARNINGS TUESDAY/TUESDAY NIGHT IS PRIMARY FOCUS. IN LARGE SCALE...STRONG SHORTWAVE IN NORTHERN STREAM CURRENTLY OVER NORTHERN MANTIOBA WILL BE CROSSING UPR MICHIGAN AND LK SUPERIOR ON TUESDAY. NAM/GFS/ECMWF DECENT AGREEMENT WITH TIMING OF LARGER SCALE IMPACTS AS THEY ALL SHOW H7-H5/H5-H3 Q-VECTOR CONVERGENCE INTO WESTERN UPR MICHIGAN BEFORE 12Z TUESDAY SPREADING TO CNTRL CWA BY 18Z AND EXITING EASTERN CWA BY 00Z WEDNESDAY. MAY SEE MINOR LGT SNOW EVEN INTO SOUTH AS THE SHORTWAVE CROSSES THE REGION. BIGGEST IMPACT THOUGH WILL BE ON LK EFFECT THAT BEGINS LATE TONIGHT. NAM AND GFS FORECAST SOUNDINGS SHOW GOOD RESPONSE FM THE WAVE WITH INVERSION HEIGHTS RISING ABOVE 5KFT LATE TONIGHT AND SPIKING UP TO 8-10KFT BY MIDDAY TUESDAY. LAKE EQUILIBRIUM LEVELS INCREASE TO 13KFT AND LAKE INDUCED CAPE VALUES CLIMB OVER 700J/KG AS H85 TEMPS FALL TO -17C TO -20C BY TUESDAY NIGHT. SOUNDINGS ALSO INDICATE INCREASING MOISTURE QUALITY TUESDAY INTO MOST OF TUESDAY NIGHT. SO...INSTABILITY AND MOISTURE NOT THE ISSUE FOR MODERATE TO HEAVY SNOW. BOTH PARAMETERS ARE THERE NO DOUBT. MAIN STICKING POINT FOR THE FORECAST ARE LOW-LEVEL WIND FIELDS AND MORE SPECIFICALLY THE WIND DIRECTION WHICH IS ALL SO CRITICAL FOR PEGGING WHERE HEAVIEST LK EFFECT WILL OCCUR. UNFORTUNATELY...NOTEABLE DIFFERENCES EXIST BTWN THE NAM/NCEP HIGH RES RUNS AND THE COARSER ECMWF/GFS AND ALSO THE GEM. MAIN ISSUE IS HOW QUICKLY SOUTH TO BRING LOW-LEVEL WIND SHIFT PASSAGE ON TUESDAY. PASSAGE OF THE TROUGH ESSENTIALLY KICKS LK EFFECT FM WNW/NW FLOW AREAS TO AREAS FAVORED BY N/NNE WINDS. USUALLY LIKE THE NAM WITH HIGHER RESOLUTION DETAILS...BUT SUCH A QUICK TROUGH PASSAGE AT 15Z-18Z ON TUESDAY IN THE NORTH SEEMS QUESTIONABLE AS SHORTWAVE TROUGH AXIS IS STILL OVER CNTRL UPR MICHIGAN AT 18Z. WOULD EXPECT THE TROUGH PASSAGE TO OCCUR TUESDAY EVENING IN THE WAKE OF THE SHORTWAVE TROUGH CROSSING THE AREA. OVERALL...PREFERRED SOLUTION IS PROBABLY MOST CLOSEST TO GFS/LOCAL REGIONAL WRF AND ECMWF. WHAT THIS MEANS IN TERMS OF LK EFFECT SNOW IS EXPECT A PROLONGED PERIOD OF LK EFFECT FOR WNW/NW FLOW AREAS LATE TONIGHT THROUGH LATE TUESDAY AFTN /WHITE PINE TO ROCKLAND/TWIN LAKES AND MAYBE AS FAR NORTH AS HOUGHTON/ AND ALSO OVER NORTHERN PARTS OF ALGER AND LUCE COUNTIES. HEAVIER LK EFFECT THEN SHIFTS TO GOGEBIC/WESTERN ONTONAGON AND MARQUETTE COUNTIES BY TUESDAY EVENING. BASED ON EXPECTED SLR/S NEARING 20:1 OR EVEN ABOVE 20:1 AND QPF WHICH WAS BLEND OF REGIONAL WRF AND EVENTUALLY THE WETTER NAM DNG LATER TUESDAY...SEEMS LIKE A SOLID ADVY EVENT IS IN STORE WITH SNOW AMOUNTS OF 4-6/5-8 INCHES IN THE 12 HOUR PERIOD FOR TUESDAY AND AGAIN ON TUESDAY NIGHT...THOUGH THE LOCATIONS OF HEAVIEST SNOW SHOULD SHIFT AROUND AS WINDS IN THE LAKE CONVECTIVE LAYER SO SOME SHEAR AND DO NOT STAY LOCKED IN THE SAME DIRECTION FOR VERY LONG PERIOD OF TIME. SOME LOCATIONS IN THE FAR WESTERN CWA /VCNTY OF IWD TO BERGLAND AND WHITE PINE/ MAY COME CLOSER TO WARNING CRITERIA TUESDAY AFTN INTO TUESDAY NIGHT BUT SINCE THE LARGER SCALE FORCING IS DIMINISHING WHEN WIND DIRECTION BECOMES A MORE FAVORABLE N-NNE TO INCREASE CONVERGENCE IN THESE AREAS...WILL OPT TO ISSUE THE ADVY AND LET FUTURE SHIFTS UPGRADE TO WARNING IF IT IS NEEDED. SNOW WILL BE THE MAIN ISSUE WITH THIS EVENT. WINDS WILL BE GUSTY 25-35 MPH...BUT STRONGEST WINDS AND BLSN/VSBY IMPACTS WILL BE MORE OVER THE NORTHERN PARTS OF THE KEWEENAW ON TUESDAY AND PERHAPS INTO NCNTRL UPR MICHIGAN ON TUESDAY NIGHT. NOT EXPECTING WIDESPREAD BLSN AS THE EVENT THIS LAST WEEKEND HAD. FOR NOW...COORDINATED WITH SHORT TERM FORECASTER AND PUT OUT LAKE EFFECT SNOW ADVISORIES FOR WESTERN TIER. ADDITIONAL HEADLINES WILL LIKELY BE ISSUED OVER NCNTRL AND POSSIBLY NORTHEAST CWA LATER TODAY OR TONIGHT...BUT SINCE THE MORE SIGNIFICANT SNOW WILL NOT OCCUR IN THESE AREAS UNTIL LATER TUESDAY OR EVEN AS LATE AS TUESDAY NIGHT IF GFS IS COMPLETELY CORRECT...WILL NOT ISSUE THOSE HEADLINES NOW. NOT ENOUGH CONFIDENCE THAT THESE AREAS WOULD SEE WARNING AMOUNTS SO DID NOT WANT TO PUT A WATCH OUT EITHER. SNOW SHOWERS PERSIST FOR N FLOW AREAS ON WEDNESDAY...BUT INTENSITY WILL BE ON THE WANE WITH LOWERING INVERSION HEIGHTS TO AT OR BLO 5KFT. EVEN AS SNOW DIMINISHES...THE DGZ WILL BE IN THE HEART OF THE LAKE CONVECTIVE LAYER SO WHAT SNOW SHOWERS ARE LEFTOVER ON WEDNESDAY WILL BE THE EFFECIENT FLUFFY TYPE. WINDS WILL BE ON THE DECREASE AS WELL...AS WILL BLSN/ASSOCIATED VSBY ISSUES. SINCE THE FLOW REMAINS LGT NORTH ALL DAY AND INSTABILITY IS MORE THAN SUFFICIENT...SNOW SHOWERS PROBABLY WILL NOT END COMPLETELY FOR FAR WEST OR NCNTRL BUT THEY MAY BECOME PINNED CLOSER TO THE SHORELINES ON WEDNESDAY NIGHT AS MESOSCALE EFFECTS/LAND BREEZES START TO DRIVE THE LOW-LEVEL CONVERGENCE. STILL COULD SEE SOME LGT SNOW ON THANKSGIVING. NO BIG IMPACT TO TRAVEL EXPECTED THOUGH. BEST CHANCE OVER THE NORTHERN TIER. WEAK TROUGH WORKS THROUGH THURSDAY NIGHT INTO FRIDAY. COULD SEE SOME SNOW SHOWERS ACROSS KEWEENAW IN WNW FLOW ON FRIDAY. WEEKEND WILL FEATURE MODEST WARMING TREND WITH SOME AREAS SLIGHTLY ABOVE FREEZING FOR DAYTIME HIGHS. LGT SNOW MAY ACCOMPANY THIS WARM AIR ADVECTION BUT LOOKS LIKE BETTER CHANCE FOR ANY SNOW ACCUMULATION WILL REMAIN TO NORTH OF CWA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 628 PM EST SUN NOV 24 2013 A GUSTY SW WIND APRCHG 30 KTS AT IWD WL ADVECT LLVL DRY AIR INTO UPR MI INTO THE EARLY MRNG HRS ON MON...SO EXPECT VFR CONDITIONS DESPITE QUITE A BIT OF MID CLD COVER. BUT AS A STRONG DISTURBANCE NOW NEAR LK WINNIPEG AND ITS ATTENDANT SFC COLD FNT DIG SEWD TOWARD THE UPR LKS...EXPECT MVFR CONDITIONS TO DVLP OVER THE W AT IWD AND CMX BY SUNRISE. WITH A STRONG UPSLOPE W WIND...THE FROPA WL BRING IFR CONDITIONS FOR A COUPLE HRS AT CMX DURING THE MRNG. ALTHOUGH SOME MVFR CIGS MAY OCCUR AT SAW WITH THE FROPA...DOWNSLOPE NATURE OF THE FLOW INDICATES THIS CONDITION WL BE MARGINAL. THE BEST CHC OF MORE PERSISTENT MVFR WX ON MON WL BE AT CMX WITH A MORE PRONOUNCED UPSLOPE W WIND...WHICH WL GUST AS HI AS 30 KTS AT THIS EXPOSED LOCATION WITH A SLOW INFLUX OF COLDER AIR/DESTABILIZATION. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 252 PM EST SUN NOV 24 2013 SW GALES EXPECTED OVER NORTH CENTRAL LAKE SUPERIOR AND THE NORTHERN LAKE MICHIGAN ZONES TONIGHT INTO MON MORNING AND WILL CONTINUE THE GALE WARNING IN LAKE SUPERIOR DUE TO CHANNELED FLOW BETWEEN THE KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO TUESDAY AND REMAIN UP TO 30 KTS. GETS CLOSE TO GALES ON LAKE SUPERIOR AGAIN TUE NIGHT INTO WED AND WILL HAVE TO WATCH THIS EVENT FOR NOW. WINDS THEN STAY BELOW 20 KNOTS FOR THE REST OF THE FORECAST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR MIZ001-003. WIND ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ013-014. LAKE EFFECT SNOW ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE SUPERIOR... GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263-264. LAKE MICHIGAN... GALE WARNING UNTIL NOON EST TODAY FOR LMZ248-250. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...07
AREA FORECAST DISCUSSION
NWS GAYLORD MI
450 AM EST MON NOV 25 2013 .SYNOPSIS... ISSUED AT 449 AM EST MON NOV 25 2013 WINTRY CONDITIONS WILL BE PREVALENT ACROSS NORTHERN MICHIGAN THROUGH THE THANKSGIVING HOLIDAY WEEK...WITH SEVERAL WEAKER WEATHER SYSTEMS DELIVERING REPEATED SHOTS OF BOTH SYSTEM AND LAKE EFFECT SNOW. THE FIRST WILL ARRIVE THIS MORNING...AS LOW PRESSURE TRACKS NEAR JAMES BAY...BRINGING A ROUND OF SNOW TO MUCH OF NORTHWEST LOWER AND EASTERN UPPER. A COLD FRONT WILL GRADUALLY WORK THROUGH THE REGION LATER TUESDAY...BRINGING RENEWED COLD CONDITIONS ALONG WITH MORE LAKE EFFECT SNOW. THAT GENERAL TREND WILL CONTINUE INTO THANKSGIVING DAY...BEFORE QUIET WEATHER MAKES A RETURN TOWARD NEXT WEEKEND. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 449 AM EST MON NOV 25 2013 WELL...THAT WAS A NICE 12-ISH HOUR RESPITE FROM THE ACTIVE WEATHER. NOW IT`S GAME ON ONCE AGAIN...WITH THE MAIN FORECAST ISSUES BEING OF THE LAKE EFFECT/ENHANCEMENT VARIETY...ALONG WITH WIND ISSUES THROUGH THE DAY TODAY. EARLY MORNING ANALYSIS PLACES VERY WEAK SHORTWAVE RIDGE AXIS JUST TO THE EAST OF NORTHERN MICHIGAN...WITH DEEP AND QUITE STRONG SOUTHWESTERLY FLOW WELL RAMPED UP ACROSS THE NORTHERN LAKES IN ADVANCE OF ANOTHER STRONG UPPER WAVE QUICKLY AMPLIFYING THROUGH SOUTHERN MANITOBA. INITIAL PUSH OF THAT WARM ADVECTION EARLIER LED TO A BRIEF AXIS OF LIGHT SNOW MARCHING THROUGH NORTHERN/EASTERN AREAS...WITH SECONDARY SURGE OF MUCH DEEPER AND STRONGER ASCENT GOING INTO GRADUAL TOP-DOWN SATURATION OFF TO OUR WEST AT THE MOMENT...AS EVIDENCED BY CEILINGS FALLING 5-8KFT OVER THE PAST FEW HOURS. MEANWHILE...QUITE THE WINDY CONDITIONS HAVE SHOWN UP RECENTLY AS CORE OF RATHER IMPRESSIVE 45-55 KNOT FLOW IS ROLLING OVERHEAD...COMBINING WITH A REMNANT UNSTABLE AIRMASS ACROSS THE LAKES TO PRODUCE SOME RATHER BEEFY WIND GUSTS PUSHING 50 MPH ALONG THE LAKE MICHIGAN SHORE. THE ABOVE MENTIONED WARM ADVECTION WILL BE IMPORTANT FOR OUR AREA THIS MORNING...AS THE ADDED MOISTURE (FROM AN INITIALLY QUITE DRY AIRMASS) GIVES A BIG BOOST OVER LAKE MICHIGAN. ALREADY SEEING THE FIRST HINTS OF THIS RIGHT NOW...BUT THE THOUGHT IS THAT DEEPER MOISTURE OVERRIDING THE LAKE WILL GO INTO THE RAPID PRODUCTION OF A SOUTHWEST FLOW LAKE BAND THE NEXT FEW HOURS...WHICH WILL ULTIMATELY GET PUNTED ONSHORE AS THE SHARP UPPER WAVE OVER MANITOBA WORKS TOWARD OUR AREA. THESE TYPES OF SETUPS ALWAYS HAVE TROUBLE WRITTEN ALL OVER THEM FROM AN IMPACT STANDPOINT...AS THERE SHOULD BE A COUPLE HOUR WINDOW FOR SOME HEAVY SNOW TO FALL UP AND DOWN THE LAKE MICHIGAN SHORELINE COUNTIES...AND PROBABLY EVEN FARTHER INLAND INTO THE HIGHER TERRAIN WHERE UPSLOPE TYPICALLY WORKS ITS MAGIC IN SUCH A SETUP. GIVEN WARMING THERMAL PROFILES...SNOW TO LIQUID RATIOS SHOULD BE RATHER LOW...AS EVIDENCED BY A QUITE DEEP ISOTHERMAL LAYER AROUND -6C PER FORECAST RAOBS...MAKING FOR MORE OF A GREASY/SLIPPERY SNOW. THROW IN SOME QUITE GUSTY WINDS AND THE STAGE IS PROBABLY SET FOR A PERIOD OF SLOPPY TRAVEL/LOW VSBYS ACROSS PRIMARILY NORTHWEST LOWER...WITH A QUICK 2-3" OF SNOW EXPECTED TO FALL. LOCAL 4/12KM APX WRF AND RECENT HRRR RUNS ARE EVEN MORE IMPRESSIVE...PAINTING AN AXIS OF 0.4" OF LIQUID UP TOWARD CHARLEVOIX/EMMET/CHEBOYGAN/OTSEGO/ANTRIM COUNTIES...WITH A SECONDARY MAXIMUM NEAR CADILLAC. GIVEN THE EXPECTED LOWER RATIOS...SHOULDN`T SEE ACCUMULATION GET OUT OF HAND...EVEN IF THE HIGHER QPF FORECASTS VERIFY. NOT SURE THIS WILL BE WORTHY OF A WINTER WEATHER HEADLINE - PROBABLY MORE LIKE AN SPS...ESPECIALLY CONSIDERING THE WORST CONDITIONS SHOULD OCCUR JUST AFTER THE MORNING COMMUTE (MAINLY 9AM-1PM). WINDS WILL SUBSIDE HEADING INTO THE AFTERNOON AS THE CORE OF STRONGEST 950-900MB FLOW EXITS EAST...ALL WHILE DEEPER MOISTURE ALSO STRIPS OUT. THAT LEAVES US IN MORE OF A LIGHT SNOW SHOWERS/SNIZZLE REGIME FOR MUCH OF THE AFTERNOON AS SOUTHWEST FLOW CONTINUES BUT WHILE CLOUD TOP TEMPS HOVER ONLY AROUND -8C. PROBABLY NOT LOOKING AT MUCH ADDITIONAL ACCUMULATION FOR MOST AREAS THROUGH LATE AFTERNOON. HOWEVER...MORE ISSUES SHOW UP BY EARLY EVENING WITH PERSISTENT HINTS OF A STRONGER FRONTAL SNOW BAND BEING BROUGHT ASHORE INTO EASTERN UPPER AS LOW PRESSURE NEARS THE SOUTHERN TIP OF JAMES BAY AND SWINGS A COLD FRONT THROUGH THE EASTERN U.P. THAT FEATURE WILL IN ALL LIKELIHOOD BECOME ABSORBED INTO THE LAKE AGGREGATE TROUGH OVER EASTERN LAKE SUPERIOR...WITH PERHAPS EVEN A WEAK CIRCULATION CENTER DEVELOPING IN RESPONSE TO YET ANOTHER STRONG UPPER WAVE ENTERING THE ARROWHEAD OF MINNESOTA. THAT SETUP COULD LEAD TO ALL KINDS OF MESOSCALE GARBAGE...BUT THE CLEAR SIGNAL IS FOR AN ENHANCED CONVERGENCE BAND TO SKIRT FAR NORTHERN CHIPPEWA COUNTY...MAINLY TOWARD PARADISE/WHITEFISH POINT...WITH MAYBE A COUPLE INCHES POSSIBLE. FARTHER SOUTH...LOOKING LIKE PERSISTENT MORE NEBULOUS SNOW SHOWERS WILL CONTINUE OVERNIGHT FOR SOUTHWEST FLOW AREAS ACROSS NORTHWEST LOWER UP TOWARD DRUMMOND ISLAND. WAS A LITTLE CONCERNED ABOUT SOME DRIZZLE POSSIBILITIES GIVEN INITIALLY SHALLOW NATURE OF MOISTURE...BUT GRADUAL INTRUSION OF COLDER AIR ALOFT SHOULD FAVOR ICE IN THE CLOUDS AS CLOUD TOP TEMPS END UP AROUND -12C BY 06Z. NO MAJOR ACCUMULATION FORESEEN FOR NORTHERN LOWER OVERNIGHT. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EST MON NOV 25 2013 A VERY ACTIVE AND RAPIDLY CHANGING WEATHER PATTERN WILL REMAIN LOCKED IN ACROSS THE GREAT LAKES THROUGH THE THANKSGIVING HOLIDAY WITH A SERIES OF SHORTWAVES AND SHOTS OF COLDER CANADIAN AIR RESULTING IN A COUPLE OF ROUNDS OF LAKE EFFECT AND LAKE ENHANCED SNOWFALL. THIS WILL ALSO PREVENT US FROM ANY SIGNIFICANT WARMING FOR THE NEXT SEVERAL DAYS. A FAIRLY QUIET PERIOD OF WEATHER IS THEN ANTICIPATED FOR FRIDAY THROUGH THE WEEKEND. TUESDAY THROUGH WEDNESDAY NIGHT...A SIMILAR SET UP LIKE TODAY...IS EXPECTED FOR TUESDAY WITH NEXT VIGOROUS SHORTWAVE...COLD FRONT AND DEEPER MOISTURE ANTICIPATED TO MOVE IN ACROSS NRN MICHIGAN. THIS TIME AROUND...WE WILL HAVE A BIT DEEPER INSTABILITY BUT LESS WIND. WEST/WSW FLOW AHEAD OF THIS FRONT...H8 TEMPS COLDER IN THE -10C TO -11C RANGE AND INVERSION HEIGHTS TO 7KFT WILL INCREASE TO NEAR 9KFT WITH COLD ADVECTION THROUGH THE DAY...BUT A DRAMATIC SHIFT IN WINDS TO OUT OF THE NNW INTO TUESDAY EVENING. MOISTURE IN THE LOWEST LEVELS ARE STARTING TO LOOK A BIT MORE MOISTURE...MORE SO ON THIS RUN OF THE BUFR SOUNDINGS. THE MOST IMPRESSIVE LES PARAMETERS ARE REALLY FOCUSED TUESDAY EVENING AFTER THE FLOW TURNS NORTHERLY WITH DEEPEST INSTABILITY WITH PASSAGE OF UPPER TROUGH AXIS/COLD AIR ALOFT. THIS WILL FOCUS THE BEST ACCUMULATION POTENTIAL ACROSS THE GTV BAY REGION AND AREAS SOUTH...WHERE ALSO...GUSTY WINDS COULD LEAD TO BLOWING AND DRIFTING ISSUES. A CONSERVATIVE 3-6 INCHES OF SNOW WILL BE POSSIBLE IN THIS REGION TUESDAY-TUESDAY NIGHT...LEADING TO THE MOST HAZARDOUS DRIVING CONDITIONS EXPECTED IN THE LONG TERM PORTION OF THE FORECAST. THE AIR MASS DRIES WITH LOWERING INVERSION HEIGHTS INTO WEDNESDAY...HOWEVER CONTINUED COLD ADVECTION AND BEST FETCH INTO GTV BAY WILL LEAD TO ANOTHER 1-2 INCHES OF SNOW THERE...WHILE AMOUNTS ARE LESS IMPRESSIVE ELSEWHERE. FAR NE LOWER NEAR ROGERS CITY/ALPENA AND OSCODA WILL SEE A SMATTERING OF 1 TO MAYBE 3 INCH LOCAL AMOUNTS TUESDAY NIGHT INTO WEDNESDAY. WEDNESDAY NIGHT...INVADING HIGHER PRESSURE AND LIGHTER WINDS FOR A LESSER THREAT TO ANYTHING SIGNIFICANT IN THE SNOW DEPARTMENT. HOWEVER...WILL HAVE TO KEEP AN EYE ON NEXT INCOMING SHORTWAVE AND WARM ADVECTION OVER THE TOP OF THE REMAINING INSTABILITY...ALTHOUGH MOST AREAS...LOOK TO HAVE A DISCONNECT FROM THE MOISTURE AND ENHANCEMENT SEEDED FROM ALOFT. SLOWLY BACKING LOW LEVEL WINDS WILL FOCUS ANY EMERGING THREAT OF RENEWED SNOW IN AND AROUND LAKE MICHIGAN. THANKSGIVING DAY AND NIGHT...THIS INCOMING WAVE IS RATHER WEAK COMPARED TO IT`S PREDECESSORS....ALTHOUGH THE WARM ADVECTION/SEEDING ALOFT DOES LOOK TO STILL HAVE SOME SORT OF ENHANCEMENT TO THE LAKE EFFECT THROUGH THE HOLIDAY AND THURSDAY NIGHT. WINDS ARE EXPECTED TO BE FAIRLY LIGHT...AND NOW SHIFTING ALL AROUND TO THE SW AS THIS ENHANCEMENT PROCESS IN UNDERWAY...SPREADING SNOWS AROUND LAKE MICHIGAN WITH LESS INLAND PENETRATION. THESE FINER DETAILS WILL REALLY HAVE TO BE EXAMINED FURTHER OVER THE NEXT COUPLE OF DAYS TO PROVIDE A MORE DETAILED HOLIDAY FORECAST. WIND DIRECTIONS AND SPEEDS BEING THE MOST CRUCIAL...WHICH HAS A BIT OF UNCERTAINTY. FRIDAY THROUGH SUNDAY...THIS WEAKER WAVE EXITS FRIDAY WITH SHALLOW MID LEVEL RIDGING...AHEAD OF NEXT ADVERTISED SHORTWAVE ARRIVING SATURDAY. A WEAK COLD FRONT LAYS ACROSS/WASHES OUT OVER NRN MICHIGAN. COULD BE ONE LAST HOORAH OF SOME WEAKER LAKE EFFECT...BUT THIS APPEARS TO BE THE LEAST OF CONCERN IN THE SERIES OF LAKE EFFECT EVENTS. THIS MAINLY DUE TO THE CONTINUED LOW LEVEL WARM ADVECTION AND GRADUAL EROSION OF THE OVERLAKE INSTABILITY. WILL HAVE RATHER SMALL CHANCES FOR SNOW IN AND AROUND LAKE MICHIGAN IN THE SW FLOW THAT PERSISTS INTO SUNDAY. TEMPERATURES WILL MODERATE BACK INTO THE LOWER HALF OF THE 30S OVER THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1159 PM EST SUN NOV 24 2013 MAINLY VFR UNTIL MONDAY MORNING...THOUGH WITH LLWS AND/OR GUSTY SW WINDS. CIGS/VSBY RESTRICTIONS ARRIVE IN -SHSN FROM NORTH TO SOUTH MONDAY MORNING. LOW PRESSURE NOW ALONG MANITOBA/ONTARIO BORDER WILL PASS JUST NORTH OF SUPERIOR ON MONDAY. SW WINDS ARE INCREASING JUST OFF THE DECK AHEAD OF THE LOW...RESULTING IN LLWS AT ALL TAF SITES OVERNIGHT (GIVING WAY TO GUSTY SW WINDS BEFORE DAWN PLN/MBL). SNOW WILL RE-DEVELOP MONDAY MORNING...1ST AT PLN...EVENTUALLY IMPACTING ALL TAF SITES. MVFR TO IFR CONDITIONS EXPECTED AT TIMES IN SHSN/BLSN...THOUGH WITH CONSIDERABLE VARIABILITY. GUSTY SW WINDS ALL DAY MONDAY...LIGHTENING UP AND VEERING A BIT TO THE WEST TOWARD EVENING. && .MARINE... ISSUED AT 449 AM EST MON NOV 25 2013 A WINDY ONE OUT THERE TO START...WITH GALES FOR MOST OF THE WATERS. THOSE WINDS WILL SUBSIDE LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING...THOUGH WILL REMAIN A BIT GUSTY IN THE 20-25 KNOT RANGE AS IS TYPICAL FOR LATE NOVEMBER. WINDS WILL GRADUALLY COME AROUND TO THE NORTHWEST ON TUESDAY AND THEN NORTH TUESDAY NIGHT AND WEDNESDAY...WITH CONTINUED GUSTS OF 25-30 KNOTS EXPECTED. COULD SEE A PERIOD OF GALES ON MAINLY LAKE MICHIGAN SOMETIME TUESDAY NIGHT... BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. HIGH PRESSURE WILL FINALLY WIN THE BATTLE BY THURSDAY...WITH A RETURN TO A BRIEF PERIOD OF MUCH LIGHTER WINDS OF THE 15 KNOTS OF LESS VARIETY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ015-016-019- 020-025-031. LH...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ323-341-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LSZ321-322. && $$ SYNOPSIS...DL SHORT TERM...DL LONG TERM...SD AVIATION...JZ MARINE...DL
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1145 AM CST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CST MON NOV 25 2013 A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY COOLER THAN THE VERY WARM ECM GUIDANCE. FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850 MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING AND WARMER LOWS. NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 327 AM CST MON NOV 25 2013 THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT. THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1144 AM CST MON NOV 25 2013 VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE NEXT 24 HOURS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. WINDS REMAIN OUT OF THE NORTHWEST THROUGH 18Z TUESDAY. SCT TO BKN CLOUD DECK WILL HAVE CIGS WELL ABOVE IFR LEVELS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...MARTIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
522 AM CST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CST MON NOV 25 2013 A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY COOLER THAN THE VERY WARM ECM GUIDANCE. FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850 MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING AND WARMER LOWS. NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 327 AM CST MON NOV 25 2013 THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT. THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 522 AM CST MON NOV 25 2013 VFR IS EXPECTED TODAY AND TONIGHT. IFR/MVFR ACROSS SCNTL NEB WILL MOVE EAST THIS MORNING...AWAY FROM THE FCST AREA. A WEAK COLD FRONT WILL MOVE THROUGH THE FCST AREA THIS MORNING FOLLOWED BY A SECOND STRONGER FRONT LATE TONIGHT. VFR CIGS ARE EXPECTED TO PREVAIL WITH BOTH FRONTAL PASSAGES. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
345 AM CST MON NOV 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CST MON NOV 25 2013 A WEAK COLD FRONT CURRENTLY MOVING THROUGH SRN SOUTH DAKOTA SHOULD CLEAR THE FORECAST AREA BY 21Z. A STRONG THERMAL RIDGE IS RUNNING OUT AHEAD OF THE COLD FRONT WITH SFC TEMPS RISING INTO THE UPPER 30S. THIS SHOULD MIX OUT THE ATMOSPHERE AND GIVE A HEAD START TO MAX TEMPS IN THE 40S. THIS IS CLOSE TO THE RAP MODEL WHICH WAS THE WARMEST SOLN NEXT TO THE ECM GUIDANCE FORECASTING HIGHS IN THE MID AND UPPER 40S. SOME MID LEVEL CLOUDINESS ASSOCIATED WITH THE COLD FRONT WOULD SUGGEST USING A FCST SLIGHTLY COOLER THAN THE VERY WARM ECM GUIDANCE. FOR TONIGHT...A REINFORCING ARCTIC FRONT...CURRENTLY ACROSS NRN SASKATCHEWAN WILL BE MOVING THROUGH SD WITH A WEAK THERMAL RIDGE RUNNING OUT AHEAD OF THIS FRONT. THE MODEL CONSENSUS SUGGESTED LOWS IN THE TEENS WHICH MIGHT BE TOO COLD. THE MODELS APPEAR TO BE PUSHING THIS FRONT INTO THE FCST AREA AROUND 06Z TONIGHT WITH H850 MB WINDS INCREASING TO 35 TO 40 KT WHICH WOULD SUPPORT MIXING AND WARMER LOWS. NO STRATUS IS EXPECTED WITH EITHER FRONT TODAY OR TONIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 327 AM CST MON NOV 25 2013 THE SOUTHERN PLAINS UPPER LEVEL LOW WILL PHASE TUESDAY WITH A STRONG SHORTWAVE DROPPING SOUTHEAST THROUGH CANADA INTO THE GREAT LAKES REGION. THIS WILL BRING HEAVY PRECIPITATION TO THE EAST COAST WEDNESDAY. ACROSS OUR AREA...ANOTHER SHOT OF ARCTIC AIR WILL PLUMMET SOUTH TUESDAY ON THE BACK SIDE OF THE DEVELOPING EASTERN CONUS STORM. THIS WILL KEEP HIGHS IN THE 20S ONCE AGAIN ACROSS PORTIONS OF NORTHERN NEBRASKA...WITH LOWER TO MID 30S ACROSS THE PANHANDLE INTO SOUTHWEST NEBRASKA. THIS COLD AIR WILL BE SHORT LIVED...AS UPPER LEVEL RIDGING AND A PACIFIC AIRMASS SPREAD EAST THROUGH THE PLAINS STARTING WEDNESDAY. THE ECMWF HAS BEEN ADVERTISING A CHINOOK EVENT WEDNESDAY...AND THIS SHOULD HELP SCOUR OUT THE ARCTIC AIR. SHOULD SEE HIGHS INTO THE 40S ACROSS WESTERN NEBRASKA...WITH LOWER 30S FARTHER EAST WHERE THE ARCTIC AIR WILL BE MORE DENSE AND TAKE LONGER TO MIX OUT. THE UPPER RIDGE BECOMES DOMINATE THANKSGIVING AND FRIDAY...WITH DRY AND MILD CONDITIONS AREA WIDE. BY THE WEEKEND...THE UPPER RIDGE WILL BEGIN TO FLATTEN...BUT IT REMAINS MILD AND DRY. MORE COLD ARCTIC AIR IS POSSIBLE BEYOND THE FORECAST PERIOD AS WE HEAD INTO NEXT WEEK...AS LARGE GULF OF ALASKA UPPER LEVEL LOW COULD DROP SOUTHEAST INTO THE PACIFIC NORTHWEST. STAY TUNED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1130 PM CST SUN NOV 24 2013 OVER THE NEXT 24 HOURS...EXPECT SCATTERED HIGH CLOUDINESS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA IN ASSOCIATION WITH AN UPPER LEVEL TROUGH OF LOW PRESSURE TO THE NORTH AND A CLOSED LOW TO THE SOUTH. CIGS WILL RANGE FROM 20000 TO 25000 FT AGL AT BOTH THE KVTN AND KLBF TERMINALS. WINDS OVERNIGHT TONIGHT WILL BE FROM THE WEST OR SOUTHWEST AT UNDER 10 KTS. WINDS WILL SHIFT TO THE NORTH MONDAY MORNING INCREASING TO 10 TO 20 KTS MONDAY AFTERNOON...THEN DECREASING TO UNDER 10 KTS MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1130 PM CST SUN NOV 24 2013 .SYNOPSIS... ISSUED AT 235 PM CST SUN NOV 24 2013 AN UPPER LOW SPUN OVER THE FOUR CORNERS ON SUNDAY AFTERNOON...WHICH PUSHED SOME MID AND HIGH LEVEL CLOUDS INTO SOUTHERN NEBRASKA. WITH THE UPPER LOW TO THE SOUTH...WESTERLY FLOW ALOFT HAS ALLOWED FOR A THERMAL RIDGE TO MOVE INTO THE NORTHERN PLAINS TODAY WHERE 850MB TEMPERATURES WERE GENERALLY 5C TO 10C AS OF 12Z THIS MORNING COMPARED TO 0C TO-5C ACROSS NEBRASKA. LOOKING AT WATER VAPOR...COULD MAKE OUT THE NEXT LOW PRESSURE SYSTEM IN LINE IN THE NORTHWEST FLOW OVER SASKATCHEWAN...WITH ANOTHER BATCH OF COLD ARCTIC AIR BEHIND IT. && .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 235 PM CST SUN NOV 24 2013 THE UPPER LEVEL LOW OVER THE FOUR CORNERS IS EXPECTED TO START GETTING INFLUENCED BY THE MEAN NORTHWEST FLOW AND START TO PUSH INTO TEXAS BY THE END OF THE DAY MONDAY. THIS SHOULD ALLOW FOR THE MID AND HIGH CLOUDS THAT HAVE BEEN SPINNING AROUND THIS SYSTEM INTO THE SOUTHERN PART OF THE FORECAST AREA FOR THE PAST SEVERAL DAYS TO GET PULLED SOUTHWARD AND AWAY FROM THE LOCAL AREA TONIGHT AND MONDAY MORNING. IT WILL ALSO ALLOW FOR SOME OF THE COLDER AIR ASSOCIATED WITH THAT SYSTEM TO GET PUSHED AWAY FROM THE AREA. MEANWHILE...THE LOW PRESSURE SYSTEM OVER SASKATCHEWAN WILL MOVE INTO ONTARIO WHICH WILL DRAG A COLD FRONT ACROSS NEBRASKA TONIGHT AND MONDAY MORNING. ALTHOUGH TEMPERATURES BEHIND THE FRONT WON/T BE MUCH COLDER FOR THE LOCAL AREA. WINDS WILL SWITCH TO THE NORTH-NORTHWEST BEHIND THE FRONT. FORECAST SOUNDINGS ARE SHOWING MINIMAL MIXING MONDAY AFTERNOON...BUT WINDS JUST ABOVE THE SURFACE ARE ABOUT 25KTS SO COULD SEE SOME 20KT WINDS AT GROUND LEVEL DURING THE AFTERNOON. ONE CONCERN WITH THE FORECAST WILL BE THE POTENTIAL FOR THE DEVELOPMENT OF SHALLOW STRATUS THIS EVENING AND TONIGHT FROM SOUTHWEST INTO CENTRAL NEBRASKA. LOW LEVEL MOISTURE ADVECTION IS BEING INDICATED INTO THE AREA AHEAD OF THE FRONT BY SEVERAL FORECAST MODELS...WITH THE NAM BEING THE MOST ROBUST SPREADING STRATUS ACROSS THE ENTIRE FORECAST AREA. DISCOUNTING THAT MODEL AND LOOKING CLOSER TO THE RAP WHICH HAS BEEN HOLDING OFF THE LOW LEVEL MOISTURE FROM MOVING INTO NEBRASKA THROUGH THE DAY TODAY. ALTHOUGH IT HAS KEPT THIS MOISTURE SOUTH TODAY...IT DOES CONTINUE TO PUSH IT INTO NEBRASKA THIS EVENING...WITH CLOUDS REMAINING UNTIL THE FRONT PUSHES THROUGH LATE TONIGHT AND MONDAY MORNING. WATCHING THE STRATUS STRUGGLE TO DEVELOP IN UPSTREAM AREAS TODAY...AND WITH THE RAP CONTINUOUSLY BACKING OFF ON THE TIMING OF BRINGING IT NORTH...JUST DON/T HAVE THE CONFIDENCE THAT THE CLOUDS WILL GET INTO THE LOCAL AREA TONIGHT AND THE FORECAST TAKES THAT INTO ACCOUNT. IF THE STRATUS DOES MOVE IN...MAY HAVE TO TAKE A LOOK AT LOW TEMPERATURES TONIGHT...ALTHOUGH THEY SHOULDN/T HAVE AN IMPACT ON HIGHS MONDAY AS THEY WOULD BE PUSHED OUT OF THE AREA BEFORE PEAK HEATING. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 235 PM CST SUN NOV 24 2013 A REINFORCING SHOT OF ARCTIC AIR WILL MOVE THROUGH THE DAKOTAS INTO NEBRASKA MONDAY NIGHT AND TUESDAY. THIS WILL BRING A GLANCING BLOW OF COLDER AIR...WHICH IS ACTUALLY NOT AS COLD AS THE PREVIOUS ONE SATURDAY. WENT A FEW DEGREES ABOVE GUIDANCE LOWS MONDAY NIGHT WITH MID/UPPER TEENS. WEAK COLD AIR ADVECTION TUESDAY WITH H85 TEMPS AS LOW AS -15C PER NAM MODEL. THIS LOOK TOO COLD AND FAVORED THE GFS -11C. USING CONSALL INTO A BLEND HIGHS NEAR 25 AT ONL TO 36 AT IML. TEMPERATURES THEN WARMUP FOR WEDNESDAY. AS SURFACE HIGH SLIDES EAST...A RETURN SOUTH TO SOUTHWEST FLOW DEVELOPS. WHILE HIGHS TO BE LIMITED TO NEAR 30 AT BBW AND ONL...THE WESTERN TIER OF COUNTIES TO WARM TO 40-43 DEGREES. DRY CONDITIONS TO ALSO PREVAIL. FOR THANKSGIVING DAY THROUGH THE WEEKEND...DRY AND SEASONAL TEMPERATURES ARE FORECAST. THE UPPER FLOW WILL REMAIN FAIRLY ZONAL. THIS HIGHLIGHTED BY AN UPPER TROUGH DIGGING FROM BRITISH COLUMBIA INTO THE NORTHERN PLAINS AND A CLOSED LOW REMAINING OFF THE CALIF. COAST. ONLY A WEAK COLD FRONT INDICATED FRIDAY NIGHT...WHICH SHOULD HAVE MINIMAL IMPACT TO HIGHS SATURDAY AND SUNDAY. ONLY VERY MINOR CHANGES TO HIGHS THROUGH THIS WEEKEND WITH MAINLY UPPER 30S TO MID 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1130 PM CST SUN NOV 24 2013 OVER THE NEXT 24 HOURS...EXPECT SCATTERED HIGH CLOUDINESS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA IN ASSOCIATION WITH AN UPPER LEVEL TROUGH OF LOW PRESSURE TO THE NORTH AND A CLOSED LOW TO THE SOUTH. CIGS WILL RANGE FROM 20000 TO 25000 FT AGL AT BOTH THE KVTN AND KLBF TERMINALS. WINDS OVERNIGHT TONIGHT WILL BE FROM THE WEST OR SOUTHWEST AT UNDER 10 KTS. WINDS WILL SHIFT TO THE NORTH MONDAY MORNING INCREASING TO 10 TO 20 KTS MONDAY AFTERNOON...THEN DECREASING TO UNDER 10 KTS MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BROOKS SHORT TERM...BROOKS LONG TERM...ROBERG AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1001 PM EST TUE NOV 26 2013 .SYNOPSIS... A STORM SYSTEM WILL MOVE THROUGH THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH A VARIETY OF MIXED...WINTRY PRECIPITATION. THIS SYSTEM WILL LIKELY CAUSE DIFFICULT TO LOCALLY HAZARDOUS TRAVEL ACROSS THE REGION. BEHIND THIS SYSTEM A RETURN TO COLD AND MAINLY DRY CONDITIONS ARE EXPECTED BY FRIDAY AND INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... AS OF 950 PM EST TUESDAY...FORECAST REMAINS MORE OR LESS ON TRACK. SNOW CONTINUES ACROSS MUCH OF THE REGION WITH ACCUMULATIONS SO FAR IN THE TRACE-2" RANGE. RAP 850/925 MB 0C LINES STILL DOING QUITE WELL DEPICTING THE CHANGEOVER FROM SNOW TO ICE/RAIN. AS OF 10PM...IT HAS PROGRESSED TO NEAR WHITE RIVER JUNCTION VERMONT WESTWARD TO GLENS FALLS AND STILL MOVING NORTHWARD. CHANGEOVER ACROSS THE REST OF THE AREA EXCEPT THE SAINT LAWRENCE VALLEY BETWEEN NOW AND 07Z FROM SOUTH TO NORTH. EXPECTING THE SAINT LAWRENCE VALLEY TO REMAIN PRIMARILY SNOW. 1 TO 3" FOR MUCH OF CHAMPLAIN VALLEY AND VERMONT BEFORE CHANGEOVER STILL LOOKS GOOD...WITH 2 TO 5" IN THE ADIRONDACKS...AND 4 TO 8" IN THE SAINT LAWRENCE VALLEY BY MORNING. ICE ACCRUAL OF UP TO A QUARTER OF AN INCH ALSO STILL LOOKS GOOD FOR PORTIONS OF THE ADIRONDACKS AND EASTERN VERMONT. OTHER CONCERN WILL BE SOME GUSTY SOUTHEAST DOWNSLOPE WINDS IN THE SOUTHERN GREENS...WHERE GUSTS UP TO 40 MPH ARE POSSIBLE OVERNIGHT. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 315 PM EST TUESDAY...MODESTLY DEEP SFC LOW THEN TRACKS ATOP OR JUST EAST OF THE FORECAST AREA DURING WEDNESDAY. THUS EXPECTING MAINLY A WIDESPREAD RAIN EVENT ACROSS VT AND CONTINUED ACCUMULATING WINTRY PCPN FROM THE DACKS INTO THE SLV AS MEAN 925/850 MB 0C LINE BACKS WESTWARD. COPIOUS MOISTURE FEED...ESP ALONG AND EAST OF THE LOW TRACK SEEMS A GOOD BET WITH MEAN MODEL PWAT ANOMALIES RANGING FROM 200-300% OF NORMAL OCCURRING ACROSS THE ERN HALF OF VERMONT DURING THE DAYLIGHT HOURS. THIS WILL CREATE SOME MODEST HYDROLOGICAL CONCERNS IN THESE AREAS WITH ADDITIONAL SUPPORT COMING FROM TIGHT BAROCLINICITY AND DEEP FRONTOGENETICAL FORCING (SEE HYDRO SECTION BELOW). TEMPERATURES ALL OVER THE PLACE...WITH NRN NY COUNTIES HOLDING MAINLY IN THE LOWER TO MID 30S WHILE AREAS ACROSS FAR EASTERN VERMONT SHOULD EASILY MAKE IT INTO THE LOWER AND MID 40S WITH A SPOT 50 NOT OUT OF THE QUESTION FROM WHITE RIVER JCT SOUTH. AS THE LOW SWINGS BY WEDNESDAY EVENING/NIGHT...THE LOWER TO MID LEVEL 0C LINE WILL BEGIN TO ADVANCE RAPIDLY EASTWARD SUCH THAT PCPN WILL RATHER QUICKLY TRANSITION BACK TO SNOW FROM EAST TO WEST DURING THE 00-06Z TIME FRAME. THUS ADDITIONAL SNOW ACCUMULATIONS EXPECTED IN ALL AREAS...ESP NORTHERN MTNS WHERE TYPICAL OROGRAPHICAL EFFECTS WILL ENHANCE LOCAL RATES. TEMPERATURES CRASHING SHARPLY DURING THE PERIOD AS WELL SO SOME QUICK FREEZE-UP OF AREA ROADS CERTAINLY POSSIBLE...SIMILAR TO A FEW NIGHTS BACK. READINGS BY MORNING GENERALLY FROM 10 TO 20 WITH A GUSTY WNW WIND. BY THURSDAY LINGERING NRN MTN SHSN SLOWLY WANE THROUGH THE DAY AS HIGH PRESSURE NOSES EASTWARD AND SUNSHINE BECOMES MORE AND MORE PREVALENT. QUITE A COLD/BLUSTERY DAY HOWEVER AS TEMPERATURES HOLD MORE OR LESS STEADY FROM 15 TO 25 UNDER STRONG COLD THERMAL ADVECTION AND CONTINUED GUSTY WNW FLOW. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 246 PM EST TUESDAY...SFC HIGH PRESSURE WITH GRADUALLY CLEAR SKIES AS AN UPPER LVL TROUGH EXITS EAST ON FRIDAY. RIDGING AT THE SFC...AND SLGT RIDGING ALOFT WILL KEEP DRY AIR OVER THE REGION THROUGH EARLY SUNDAY. COLD TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE MODERATED BY RETURN FLOW ON SATURDAY AS THE SFC HIGH SHIFTS EWD TOWARD NOVA SCOTIA. MAX TEMPS IN THE TEENS AND 20S ON FRIDAY WITH MIN TEMPS IN THE SINGLE DIGITS...AND NEGATIVE SINGLE DIGITS WILL WARM INTO THE TEENS SATURDAY NT AND 20S-M30S ON SUNDAY. UPPER LVL SHORTWAVE WILL BRING CLOUDS AND CHC FOR SNOW SUNDAY INTO EARLY MONDAY WITH THE POSSIBILITY OF A COASTAL STORM DEVELOPING MONDAY NT INTO TUESDAY. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... THROUGH 00Z THURSDAY...SNOW HAS OVERSPREAD MOST OF FORECAST AREA WITH VSBYS LOWERING QUICKLY TO IFR AND CIGS TO MVFR. WIDESPREAD IFR WITH AREAS OF MVFR EXPECTED THROUGH THE PERIOD. SNOW WILL TRANSITION TO RAIN OVERNIGHT AT ALL SITES EXCEPT KMSS AND KSLK. LOOK FOR SNOW TO MIX WITH SLEET AND POSSIBLY FREEZING RAIN BY 02Z AT KRUT...AND BETWEEN 04-06Z AT KMPV/KBTV/KPBG/KSLK. MIX WILL THEN CHANGE TO RAIN AT KRUT BY 04Z AND BETWEEN 06Z-10Z AT KMPV/KBTV/KPBG. MIX CONTINUES AT KSLK WITH SNOW AT KMSS...WHICH MAY BE HEAVY AT TIMES. PRECIPITATION THEN TRANSITIONS BACK TO SNOW FROM WEST TO EAST ACROSS THE AREA WEDNESDAY AFTERNOON. STRONG LOW LVL JET WILL APPROACH EASTERN VT...CREATING LLWS OF 40-50KTS FOR KRUT AND KMPV BETWEEN 08Z-14Z. AT THE SFC...WINDS WILL BE LESS THAN 10 KTS TONIGHT AT ALL SITES EXCEPT KRUT WHICH WILL SEE SOUTHEAST WINDS GUSTING 20-25 KTS. WINDS BECOMING NORTHERLY 8-15 KTS ACROSS THE REGION ON WEDNESDAY AS SFC LOW TRACKS FROM NEAR NYC WEDNESDAY MORNING INTO EASTERN NEW ENGLAND. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 00Z THURSDAY THROUGH 18Z THURSDAY...MVFR AND IFR CATEGORIES CONTINUE INTO THANKSGIVING MORNING. ANY MIXED PRECIPITATION CHANGES TO ALL SNOW WEDNESDAY EVENING AND THEN AND TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY THROUGH 12Z SUNDAY...MAINLY VFR AS HIGH PRESSURE MOVES ACROSS REGION. 12Z SUNDAY ONWARD...VFR/MVFR IN SCATTERED SNOW SHOWERS. && .HYDROLOGY... AS OF 315 PM EST TUESDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS CONTINUE TO SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE A SOLID 1.5 TO 2.5 QPF EVENT IS LIKELY. PROBLEMATIC WILL BE AT LEAST SOME FRONT END FROZEN PCPN TONIGHT AND TYPICAL SHADOWING EFFECTS DEPENDING ON LOCALE DURING WEDNESDAY. HOWEVER SSHP OUTPUT USING FORCAST QPF FROM 06Z-00Z WED AND INCORPORATING A MODEST 0.15 TO 0.25 SWE MELT SHOW SEVERAL EASTERN/SOUTHERN VT WATERSHEDS NEARING BANKFULL LATER WED/WED NIGHT. THIS IS IN CLOSE AGREEMENT WITH COORDINATED NERFC/AHPS FORECASTS AND GIVEN ANOMALOUS 12-HR PWAT SURGE NOTED ABOVE...HAVE OPTED TO ISSUE A FLOOD WATCH FOR MUCH OF THIS AREA ACCORDINGLY. THIS IS NOT A HIGH END EVENT...BUT SOME MINOR/NUISANCE FLOODING ALONG BOTH HEADWATER AND MAINSTEM RIVERS WILL BE POSSIBLE LATER WED/WED NT. && .MARINE... AS OF 258 PM EST TUESDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT THROUGH AT LEAST MIDNIGHT. WHILE WINDS HAVE DROPPED OFF A LITTLE BIT FROM THIS MORNING...THEY ARE STILL HOVERING AROUND 25 KNOTS AT COLCHESTER REEF THIS AFTERNOON. A SLIGHT LULL MAY OCCUR EARLY THIS EVENING BEFORE WINDS PICK UP AGAIN THROUGH MIDNIGHT. AFTER MIDNIGHT THOUGH...WINDS SHIFT TO THE NORTH BY WEDNESDAY MORNING AND DECREASE BELOW ADVISORY LEVELS. THIS LULL WILL BE BRIEF THOUGH AS A COLD FRONT PASSES THROUGH THE REGION WEDNESDAY EVENING...WINDS WILL SHIFT TO THE NORTHWEST AND BECOME STRONG AGAIN AT 25-35 KNOTS...WITH WAVES BUILDING TO 4 TO 6 FEET. ANOTHER ADVISORY WILL LIKELY BE NEEDED IN THE FUTURE. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VTZ001>012-016>019. FLOOD WATCH FROM 7 AM EST WEDNESDAY THROUGH LATE WEDNESDAY NIGHT FOR VTZ004-007-008-010>012-018-019. NY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NYZ026-027- 029>031-034-087. WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR NYZ028- 035. && $$ SYNOPSIS...JMG NEAR TERM...MUCCILLI SHORT TERM...JMG LONG TERM...KGM AVIATION...RJS HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
706 PM EST TUE NOV 26 2013 .SYNOPSIS... A STORM SYSTEM WILL MOVE THROUGH THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH A VARIETY OF MIXED...WINTRY PRECIPITATION. THIS SYSTEM WILL LIKELY CAUSE DIFFICULT TO LOCALLY HAZARDOUS TRAVEL ACROSS THE REGION. BEHIND THIS SYSTEM A RETURN TO COLD AND MAINLY DRY CONDITIONS ARE EXPECTED BY FRIDAY AND INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... AS OF 623 PM EST TUESDAY...GOING FORECAST REMAINS IN PRETTY GOOD SHAPE. LIGHT SNOW HAS OVERSPREAD MUCH OF THE REGION THIS EVENING AND WILL CONTINUE WORKING NORTHWARD AS LOW PRESSURE LOCATED IN THE SOUTHEASTERN US MOVES NORTHEASTWARD. PRECIPITATION-TYPE REMAINS THE MOST CHALLENGING ASPECT OF THIS SYSTEM. RAP 850/925 MB 0C LINES DOING FAIRLY WELL SO FAR THIS EVENING DELINEATING BETWEEN SNOW AND SLEET/FREEZING RAIN...THUS LEANED TOWARDS IT AND THE HRRR FOR NEXT SEVERAL HOURS. CHANGEOVER AT RUTLAND AND PORTIONS OF SOUTHERN VT TO MIXED PRECIP OR RAIN AROUND 02Z...AND MUCH OF THE REST OF THE AREA EXCEPT THE SAINT LAWRENCE VALLEY 04-07Z. EXPECTING THE SAINT LAWRENCE VALLEY TO REMAIN PRIMARILY SNOW. 1 TO 3" FOR MUCH OF CHAMPLAIN VALLEY AND VERMONT BEFORE CHANGEOVER STILL LOOKS GOOD...WITH 2 TO 5" IN THE ADIRONDACKS...AND 4 TO 8" IN THE SAINT LAWRENCE VALLEY BY MORNING. ICE ACCRUAL OF UP TO A THIRD OF AN INCH ALSO STILL LOOKS GOOD FOR PORTIONS OF THE ADIRONDACKS AND EASTERN VERMONT. OTHER CONCERN WILL BE SOME GUSTY SOUTHEAST DOWNSLOPE WINDS IN THE SOUTHERN GREENS...WHERE GUSTS UP TO 40 MPH ARE POSSIBLE OVERNIGHT. PREVIOUS DISCUSSION FROM 315 PM TUESDAY... FORECAST REMAINS MORE OR LESS ON TRACK AS WE HEAD INTO THE EVENING AND OVERNIGHT HOURS AS LOW PRESSURE AND ASSOCIATED PRECIPITATION ADVANCE STEADILY NORTHEAST INTO THE REGION. BOTH GLOBAL AND MESOSCALE MODELS CONTINUE TO SHOW VERY GOOD AGREEMENT ON TRACK OF SFC LOW AND DEPICTION/EVOLUTION OF THE MEAN 925/850/700 MB 0C LINE ADVANCING NORTH/NORTHWESTWARD INTO THE AREA. THUS PRIOR IDEA OF A WIDESPREAD WINTRY MIX OVERSPREADING OUR AREA STILL LOOKS RIGHT ON TRACK. SOME LIGHT TO MODEST SNOW ACCUMULATIONS POSSIBLE DURING THIS PERIOD...ESPECIALLY ACROSS OUR NRN NY COUNTIES WHICH WILL BE DEEPER WITHIN THE MARGINALLY COLD AIRMASS. FURTHER EAST INTO VT...LIKELY A MIX TRANSITIONING SLOWLY TO MAINLY AN ALL RAIN SCENARIO AS THE DAY DAWNS ON WEDNESDAY. MOST PROBLEMATIC WILL BE THE POTENTIAL FOR SOME LOCALIZED/SCATTERED AREAS OF LIGHT ICING (ESP ERN VT) DURING THE FIRST HALF OF THE NIGHT AS INITIAL SFC EVAPORATIVE EFFECTS AND MARGINALLY COLD PAVEMENT TEMPERATURES PROMOTE SOME LIGHT ACCUMULATIONS. MODELS CONSISTENT IN SHOWING THIS...WITH MOST PRONOUNCED THREAT OF LIGHT ICING ACTUALLY OCCURRING ON MID-SLOPE TERRAIN FROM 500-1500 FT ACROSS THE ERN HALF OF VT. WITH VARIABILITY IN WIND FLOW AND PRONOUNCED WARM THERMAL ADVECTION ALOFT...TEMPERATURES WILL REMAIN NEARLY STEADY OR SLOWLY RISE OVERNIGHT...ESP ACROSS VT. THUS HAVE LEANED HEAVILY ON THE RAW HOURLY WRF MODEL OUTPUT WHICH CAPTURES THESE TRENDS BEST. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 315 PM EST TUESDAY...MODESTLY DEEP SFC LOW THEN TRACKS ATOP OR JUST EAST OF THE FORECAST AREA DURING WEDNESDAY. THUS EXPECTING MAINLY A WIDESPREAD RAIN EVENT ACROSS VT AND CONTINUED ACCUMULATING WINTRY PCPN FROM THE DACKS INTO THE SLV AS MEAN 925/850 MB 0C LINE BACKS WESTWARD. COPIOUS MOISTURE FEED...ESP ALONG AND EAST OF THE LOW TRACK SEEMS A GOOD BET WITH MEAN MODEL PWAT ANOMALIES RANGING FROM 200-300% OF NORMAL OCCURRING ACROSS THE ERN HALF OF VERMONT DURING THE DAYLIGHT HOURS. THIS WILL CREATE SOME MODEST HYDROLOGICAL CONCERNS IN THESE AREAS WITH ADDITIONAL SUPPORT COMING FROM TIGHT BAROCLINICITY AND DEEP FRONTOGENETICAL FORCING (SEE HYDRO SECTION BELOW). TEMPERATURES ALL OVER THE PLACE...WITH NRN NY COUNTIES HOLDING MAINLY IN THE LOWER TO MID 30S WHILE AREAS ACROSS FAR EASTERN VERMONT SHOULD EASILY MAKE IT INTO THE LOWER AND MID 40S WITH A SPOT 50 NOT OUT OF THE QUESTION FROM WHITE RIVER JCT SOUTH. AS THE LOW SWINGS BY WEDNESDAY EVENING/NIGHT...THE LOWER TO MID LEVEL 0C LINE WILL BEGIN TO ADVANCE RAPIDLY EASTWARD SUCH THAT PCPN WILL RATHER QUICKLY TRANSITION BACK TO SNOW FROM EAST TO WEST DURING THE 00-06Z TIME FRAME. THUS ADDITIONAL SNOW ACCUMULATIONS EXPECTED IN ALL AREAS...ESP NORTHERN MTNS WHERE TYPICAL OROGRAPHICAL EFFECTS WILL ENHANCE LOCAL RATES. TEMPERATURES CRASHING SHARPLY DURING THE PERIOD AS WELL SO SOME QUICK FREEZE-UP OF AREA ROADS CERTAINLY POSSIBLE...SIMILAR TO A FEW NIGHTS BACK. READINGS BY MORNING GENERALLY FROM 10 TO 20 WITH A GUSTY WNW WIND. BY THURSDAY LINGERING NRN MTN SHSN SLOWLY WANE THROUGH THE DAY AS HIGH PRESSURE NOSES EASTWARD AND SUNSHINE BECOMES MORE AND MORE PREVALENT. QUITE A COLD/BLUSTERY DAY HOWEVER AS TEMPERATURES HOLD MORE OR LESS STEADY FROM 15 TO 25 UNDER STRONG COLD THERMAL ADVECTION AND CONTINUED GUSTY WNW FLOW. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 246 PM EST TUESDAY...SFC HIGH PRESSURE WITH GRADUALLY CLEAR SKIES AS AN UPPER LVL TROUGH EXITS EAST ON FRIDAY. RIDGING AT THE SFC...AND SLGT RIDGING ALOFT WILL KEEP DRY AIR OVER THE REGION THROUGH EARLY SUNDAY. COLD TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE MODERATED BY RETURN FLOW ON SATURDAY AS THE SFC HIGH SHIFTS EWD TOWARD NOVA SCOTIA. MAX TEMPS IN THE TEENS AND 20S ON FRIDAY WITH MIN TEMPS IN THE SINGLE DIGITS...AND NEGATIVE SINGLE DIGITS WILL WARM INTO THE TEENS SATURDAY NT AND 20S-M30S ON SUNDAY. UPPER LVL SHORTWAVE WILL BRING CLOUDS AND CHC FOR SNOW SUNDAY INTO EARLY MONDAY WITH THE POSSIBILITY OF A COASTAL STORM DEVELOPING MONDAY NT INTO TUESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THROUGH 00Z THURSDAY...SNOW HAS OVERSPREAD MOST OF FORECAST AREA WITH VSBYS LOWERING QUICKLY TO IFR AND CIGS TO MVFR. WIDESPREAD IFR WITH AREAS OF MVFR EXPECTED THROUGH THE PERIOD. SNOW WILL TRANSITION TO RAIN OVERNIGHT AT ALL SITES EXCEPT KMSS AND KSLK. LOOK FOR SNOW TO MIX WITH SLEET AND POSSIBLY FREEZING RAIN BY 02Z AT KRUT...AND BETWEEN 04-06Z AT KMPV/KBTV/KPBG/KSLK. MIX WILL THEN CHANGE TO RAIN AT KRUT BY 04Z AND BETWEEN 06Z-10Z AT KMPV/KBTV/KPBG. MIX CONTINUES AT KSLK WITH SNOW AT KMSS...WHICH MAY BE HEAVY AT TIMES. PRECIPITATION THEN TRANSITIONS BACK TO SNOW FROM WEST TO EAST ACROSS THE AREA WEDNESDAY AFTERNOON. STRONG LOW LVL JET WILL APPROACH EASTERN VT...CREATING LLWS OF 40-50KTS FOR KRUT AND KMPV BETWEEN 08Z-14Z. AT THE SFC...WINDS WILL BE LESS THAN 10 KTS TONIGHT AT ALL SITES EXCEPT KRUT WHICH WILL SEE SOUTHEAST WINDS GUSTING 20-25 KTS. WINDS BECOMING NORTHERLY 8-15 KTS ACROSS THE REGION ON WEDNESDAY AS SFC LOW TRACKS FROM NEAR NYC WEDNESDAY MORNING INTO EASTERN NEW ENGLAND. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 00Z THURSDAY THROUGH 18Z THURSDAY...MVFR AND IFR CATEGORIES CONTINUE INTO THANKSGIVING MORNING. ANY MIXED PRECIPITATION CHANGES TO ALL SNOW WEDNESDAY EVENING AND THEN AND TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY THROUGH 12Z SUNDAY...MAINLY VFR AS HIGH PRESSURE MOVES ACROSS REGION. 12Z SUNDAY ONWARD...VFR/MVFR IN SCATTERED SNOW SHOWERS. && .HYDROLOGY... AS OF 315 PM EST TUESDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS CONTINUE TO SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE A SOLID 1.5 TO 2.5 QPF EVENT IS LIKELY. PROBLEMATIC WILL BE AT LEAST SOME FRONT END FROZEN PCPN TONIGHT AND TYPICAL SHADOWING EFFECTS DEPENDING ON LOCALE DURING WEDNESDAY. HOWEVER SSHP OUTPUT USING FORCAST QPF FROM 06Z-00Z WED AND INCORPORATING A MODEST 0.15 TO 0.25 SWE MELT SHOW SEVERAL EASTERN/SOUTHERN VT WATERSHEDS NEARING BANKFULL LATER WED/WED NIGHT. THIS IS IN CLOSE AGREEMENT WITH COORDINATED NERFC/AHPS FORECASTS AND GIVEN ANOMALOUS 12-HR PWAT SURGE NOTED ABOVE...HAVE OPTED TO ISSUE A FLOOD WATCH FOR MUCH OF THIS AREA ACCORDINGLY. THIS IS NOT A HIGH END EVENT...BUT SOME MINOR/NUISANCE FLOODING ALONG BOTH HEADWATER AND MAINSTEM RIVERS WILL BE POSSIBLE LATER WED/WED NT. && .MARINE... AS OF 258 PM EST TUESDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT THROUGH AT LEAST MIDNIGHT. WHILE WINDS HAVE DROPPED OFF A LITTLE BIT FROM THIS MORNING...THEY ARE STILL HOVERING AROUND 25 KNOTS AT COLCHESTER REEF THIS AFTERNOON. A SLIGHT LULL MAY OCCUR EARLY THIS EVENING BEFORE WINDS PICK UP AGAIN THROUGH MIDNIGHT. AFTER MIDNIGHT THOUGH...WINDS SHIFT TO THE NORTH BY WEDNESDAY MORNING AND DECREASE BELOW ADVISORY LEVELS. THIS LULL WILL BE BRIEF THOUGH AS A COLD FRONT PASSES THROUGH THE REGION WEDNESDAY EVENING...WINDS WILL SHIFT TO THE NORTHWEST AND BECOME STRONG AGAIN AT 25-35 KNOTS...WITH WAVES BUILDING TO 4 TO 6 FEET. ANOTHER ADVISORY WILL LIKELY BE NEEDED IN THE FUTURE. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VTZ001>012-016>019. FLOOD WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT FOR VTZ004-007-008-010>012-018-019. NY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NYZ026-027- 029>031-034-087. WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR NYZ028- 035. && $$ SYNOPSIS...JMG NEAR TERM...JMG/MUCCILLI SHORT TERM...JMG LONG TERM...KGM AVIATION...RJS HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
635 PM EST TUE NOV 26 2013 .SYNOPSIS... A STORM SYSTEM WILL MOVE THROUGH THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH A VARIETY OF MIXED...WINTRY PRECIPITATION. THIS SYSTEM WILL LIKELY CAUSE DIFFICULT TO LOCALLY HAZARDOUS TRAVEL ACROSS THE REGION. BEHIND THIS SYSTEM A RETURN TO COLD AND MAINLY DRY CONDITIONS ARE EXPECTED BY FRIDAY AND INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... AS OF 623 PM EST TUESDAY...GOING FORECAST REMAINS IN PRETTY GOOD SHAPE. LIGHT SNOW HAS OVERSPREAD MUCH OF THE REGION THIS EVENING AND WILL CONTINUE WORKING NORTHWARD AS LOW PRESSURE LOCATED IN THE SOUTHEASTERN US MOVES NORTHEASTWARD. PRECIPITATION-TYPE REMAINS THE MOST CHALLENGING ASPECT OF THIS SYSTEM. RAP 850/925 MB 0C LINES DOING FAIRLY WELL SO FAR THIS EVENING DELINEATING BETWEEN SNOW AND SLEET/FREEZING RAIN...THUS LEANED TOWARDS IT AND THE HRRR FOR NEXT SEVERAL HOURS. CHANGEOVER AT RUTLAND AND PORTIONS OF SOUTHERN VT TO MIXED PRECIP OR RAIN AROUND 02Z...AND MUCH OF THE REST OF THE AREA EXCEPT THE SAINT LAWRENCE VALLEY 04-07Z. EXPECTING THE SAINT LAWRENCE VALLEY TO REMAIN PRIMARILY SNOW. 1 TO 3" FOR MUCH OF CHAMPLAIN VALLEY AND VERMONT BEFORE CHANGEOVER STILL LOOKS GOOD...WITH 2 TO 5" IN THE ADIRONDACKS...AND 4 TO 8" IN THE SAINT LAWRENCE VALLEY BY MORNING. ICE ACCRUAL OF UP TO A THIRD OF AN INCH ALSO STILL LOOKS GOOD FOR PORTIONS OF THE ADIRONDACKS AND EASTERN VERMONT. OTHER CONCERN WILL BE SOME GUSTY SOUTHEAST DOWNSLOPE WINDS IN THE SOUTHERN GREENS...WHERE GUSTS UP TO 40 MPH ARE POSSIBLE OVERNIGHT. PREVIOUS DISCUSSION FROM 315 PM TUESDAY... FORECAST REMAINS MORE OR LESS ON TRACK AS WE HEAD INTO THE EVENING AND OVERNIGHT HOURS AS LOW PRESSURE AND ASSOCIATED PRECIPITATION ADVANCE STEADILY NORTHEAST INTO THE REGION. BOTH GLOBAL AND MESOSCALE MODELS CONTINUE TO SHOW VERY GOOD AGREEMENT ON TRACK OF SFC LOW AND DEPICTION/EVOLUTION OF THE MEAN 925/850/700 MB 0C LINE ADVANCING NORTH/NORTHWESTWARD INTO THE AREA. THUS PRIOR IDEA OF A WIDESPREAD WINTRY MIX OVERSPREADING OUR AREA STILL LOOKS RIGHT ON TRACK. SOME LIGHT TO MODEST SNOW ACCUMULATIONS POSSIBLE DURING THIS PERIOD...ESPECIALLY ACROSS OUR NRN NY COUNTIES WHICH WILL BE DEEPER WITHIN THE MARGINALLY COLD AIRMASS. FURTHER EAST INTO VT...LIKELY A MIX TRANSITIONING SLOWLY TO MAINLY AN ALL RAIN SCENARIO AS THE DAY DAWNS ON WEDNESDAY. MOST PROBLEMATIC WILL BE THE POTENTIAL FOR SOME LOCALIZED/SCATTERED AREAS OF LIGHT ICING (ESP ERN VT) DURING THE FIRST HALF OF THE NIGHT AS INITIAL SFC EVAPORATIVE EFFECTS AND MARGINALLY COLD PAVEMENT TEMPERATURES PROMOTE SOME LIGHT ACCUMULATIONS. MODELS CONSISTENT IN SHOWING THIS...WITH MOST PRONOUNCED THREAT OF LIGHT ICING ACTUALLY OCCURRING ON MID-SLOPE TERRAIN FROM 500-1500 FT ACROSS THE ERN HALF OF VT. WITH VARIABILITY IN WIND FLOW AND PRONOUNCED WARM THERMAL ADVECTION ALOFT...TEMPERATURES WILL REMAIN NEARLY STEADY OR SLOWLY RISE OVERNIGHT...ESP ACROSS VT. THUS HAVE LEANED HEAVILY ON THE RAW HOURLY WRF MODEL OUTPUT WHICH CAPTURES THESE TRENDS BEST. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 315 PM EST TUESDAY...MODESTLY DEEP SFC LOW THEN TRACKS ATOP OR JUST EAST OF THE FORECAST AREA DURING WEDNESDAY. THUS EXPECTING MAINLY A WIDESPREAD RAIN EVENT ACROSS VT AND CONTINUED ACCUMULATING WINTRY PCPN FROM THE DACKS INTO THE SLV AS MEAN 925/850 MB 0C LINE BACKS WESTWARD. COPIOUS MOISTURE FEED...ESP ALONG AND EAST OF THE LOW TRACK SEEMS A GOOD BET WITH MEAN MODEL PWAT ANOMALIES RANGING FROM 200-300% OF NORMAL OCCURRING ACROSS THE ERN HALF OF VERMONT DURING THE DAYLIGHT HOURS. THIS WILL CREATE SOME MODEST HYDROLOGICAL CONCERNS IN THESE AREAS WITH ADDITIONAL SUPPORT COMING FROM TIGHT BAROCLINICITY AND DEEP FRONTOGENETICAL FORCING (SEE HYDRO SECTION BELOW). TEMPERATURES ALL OVER THE PLACE...WITH NRN NY COUNTIES HOLDING MAINLY IN THE LOWER TO MID 30S WHILE AREAS ACROSS FAR EASTERN VERMONT SHOULD EASILY MAKE IT INTO THE LOWER AND MID 40S WITH A SPOT 50 NOT OUT OF THE QUESTION FROM WHITE RIVER JCT SOUTH. AS THE LOW SWINGS BY WEDNESDAY EVENING/NIGHT...THE LOWER TO MID LEVEL 0C LINE WILL BEGIN TO ADVANCE RAPIDLY EASTWARD SUCH THAT PCPN WILL RATHER QUICKLY TRANSITION BACK TO SNOW FROM EAST TO WEST DURING THE 00-06Z TIME FRAME. THUS ADDITIONAL SNOW ACCUMULATIONS EXPECTED IN ALL AREAS...ESP NORTHERN MTNS WHERE TYPICAL OROGRAPHICAL EFFECTS WILL ENHANCE LOCAL RATES. TEMPERATURES CRASHING SHARPLY DURING THE PERIOD AS WELL SO SOME QUICK FREEZE-UP OF AREA ROADS CERTAINLY POSSIBLE...SIMILAR TO A FEW NIGHTS BACK. READINGS BY MORNING GENERALLY FROM 10 TO 20 WITH A GUSTY WNW WIND. BY THURSDAY LINGERING NRN MTN SHSN SLOWLY WANE THROUGH THE DAY AS HIGH PRESSURE NOSES EASTWARD AND SUNSHINE BECOMES MORE AND MORE PREVALENT. QUITE A COLD/BLUSTERY DAY HOWEVER AS TEMPERATURES HOLD MORE OR LESS STEADY FROM 15 TO 25 UNDER STRONG COLD THERMAL ADVECTION AND CONTINUED GUSTY WNW FLOW. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 246 PM EST TUESDAY...SFC HIGH PRESSURE WITH GRADUALLY CLEAR SKIES AS AN UPPER LVL TROUGH EXITS EAST ON FRIDAY. RIDGING AT THE SFC...AND SLGT RIDGING ALOFT WILL KEEP DRY AIR OVER THE REGION THROUGH EARLY SUNDAY. COLD TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE MODERATED BY RETURN FLOW ON SATURDAY AS THE SFC HIGH SHIFTS EWD TOWARD NOVA SCOTIA. MAX TEMPS IN THE TEENS AND 20S ON FRIDAY WITH MIN TEMPS IN THE SINGLE DIGITS...AND NEGATIVE SINGLE DIGITS WILL WARM INTO THE TEENS SATURDAY NT AND 20S-M30S ON SUNDAY. UPPER LVL SHORTWAVE WILL BRING CLOUDS AND CHC FOR SNOW SUNDAY INTO EARLY MONDAY WITH THE POSSIBILITY OF A COASTAL STORM DEVELOPING MONDAY NT INTO TUESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THROUGH 18Z WEDNESDAY...VFR CONDITIONS ACROSS MOST OF THE AREA...WITH KSLK AND KRUT EXPERIENCING MVFR CIGS. STEADY SNOW WITH MVFR CONDITIONS ARRIVES BTWN 23Z AND 01Z AT ALL SITES. OVERNIGHT...-SN WILL TRANSITION TO -RA...WITH MIX OF -SN AND -PL AT VT TERMINALS AND KPBG AFTER 05Z. EXPECT ABOUT 2-3 HOURS OF PSBL MIX THROUGHOUT VT AND KPBG...BEFORE TRANSITIONING TO -RA BTWN 08Z AND 10Z. PRECIP SHOULD REMAIN -SN AT KMSS AND KSLK. HEAVIER PRECIP TRIES TO MOVE IN DURING THIS PTYPE TRANSITION...PSBLY BRINGING IFR/LIFR CONDITIONS. PRECIP DOES NOT LOOK TO LIGHTEN TIL LATE WEDNESDAY MORNING...MAINLY ACROSS PORTIONS OF NY. STRONG LOW LVL JET WILL APPROACH ERN VT...CREATING LLWS OF 40-50KTS FOR KRUT AND KMPV AFTER 08Z. AT THE SFC...SOUTHERLY WINDS AT 5-15KTS WILL CONTINUE THIS AFTN WITH SOME GUSTS NEAR 20KTS AT KBTV/KMSS. AS SFC LOW TRACKS TOWARD NYC EARLY WEDNESDAY MORNING...WINDS WILL SHIFT OUT OF THE NORTH AT 5-10KTS. OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY... 18Z WEDNESDAY THROUGH 18Z THURSDAY...MVFR AND IFR CATEGORIES CONTINUE INTO THANKSGIVING MORNING. PRECIPITATION CHANGES BACK TO SNOW WEDNESDAY NIGHT AND TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY ONWARD...MAINLY VFR AS HIGH PRESSURE BUILD INTO REGION. && .HYDROLOGY... AS OF 315 PM EST TUESDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS CONTINUE TO SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE A SOLID 1.5 TO 2.5 QPF EVENT IS LIKELY. PROBLEMATIC WILL BE AT LEAST SOME FRONT END FROZEN PCPN TONIGHT AND TYPICAL SHADOWING EFFECTS DEPENDING ON LOCALE DURING WEDNESDAY. HOWEVER SSHP OUTPUT USING FORCAST QPF FROM 06Z-00Z WED AND INCORPORATING A MODEST 0.15 TO 0.25 SWE MELT SHOW SEVERAL EASTERN/SOUTHERN VT WATERSHEDS NEARING BANKFULL LATER WED/WED NIGHT. THIS IS IN CLOSE AGREEMENT WITH COORDINATED NERFC/AHPS FORECASTS AND GIVEN ANOMALOUS 12-HR PWAT SURGE NOTED ABOVE...HAVE OPTED TO ISSUE A FLOOD WATCH FOR MUCH OF THIS AREA ACCORDINGLY. THIS IS NOT A HIGH END EVENT...BUT SOME MINOR/NUISANCE FLOODING ALONG BOTH HEADWATER AND MAINSTEM RIVERS WILL BE POSSIBLE LATER WED/WED NT. && .MARINE... AS OF 258 PM EST TUESDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT THROUGH AT LEAST MIDNIGHT. WHILE WINDS HAVE DROPPED OFF A LITTLE BIT FROM THIS MORNING...THEY ARE STILL HOVERING AROUND 25 KNOTS AT COLCHESTER REEF THIS AFTERNOON. A SLIGHT LULL MAY OCCUR EARLY THIS EVENING BEFORE WINDS PICK UP AGAIN THROUGH MIDNIGHT. AFTER MIDNIGHT THOUGH...WINDS SHIFT TO THE NORTH BY WEDNESDAY MORNING AND DECREASE BELOW ADVISORY LEVELS. THIS LULL WILL BE BRIEF THOUGH AS A COLD FRONT PASSES THROUGH THE REGION WEDNESDAY EVENING...WINDS WILL SHIFT TO THE NORTHWEST AND BECOME STRONG AGAIN AT 25-35 KNOTS...WITH WAVES BUILDING TO 4 TO 6 FEET. ANOTHER ADVISORY WILL LIKELY BE NEEDED IN THE FUTURE. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VTZ001>012-016>019. FLOOD WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT FOR VTZ004-007-008-010>012-018-019. NY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NYZ026-027- 029>031-034-087. WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR NYZ028- 035. && $$ SYNOPSIS...JMG NEAR TERM...JMG/MUCCILLI SHORT TERM...JMG LONG TERM...KGM AVIATION...KGM HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
321 PM CST MON NOV 25 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 320 PM CST MON NOV 25 2013 A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT. A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW BEING BLOWN NEAR THE WEATHER SENSOR. HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER 20S SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM CST MON NOV 25 2013 LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND. A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/ WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST. THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE MODELS RUNS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 320 PM CST MON NOV 25 2013 EXPECT CONTINUED MAINLY MVFR CEILINGS AT KISN/KMOT/KBIS/KJMS. A NW WIND WILL GUST BETWEEN 20 AND 30 KTS THROUGH THE AFTERNOON...WITH THE GUSTINESS DIMINISHING THIS EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM/AVIATION...RP KINNEY LONG TERM...KS
AREA FORECAST DISCUSSION
NWS TULSA OK
1117 PM CST SUN NOV 24 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. NEXT ROUND OF WINTER PRECIPITATION DEVELOPING OVER NORTH TEXAS WILL SPREAD NE OVERNIGHT INTO SE OKLAHOMA AND EVENTUALLY NW ARKANSAS BY 12Z WITH WIDESPREAD MVFR CONDITIONS DEVELOPING. TEMPERATURE PROFILES CONTINUE TO SUPPORT MIX OF SLEET/SNOW WHICH WILL EVENTUALLY TRANSITION TO LIQUID BEFORE ENDING IN THE AFTERNOON. NE OKLAHOMA SITES SHOULD SEE SOME IMPROVEMENT IN CEILINGS LATE IN THE PERIOD. && .PREV DISCUSSION... /ISSUED 924 PM CST SUN NOV 24 2013/ ..UPDATE... DISCUSSION... INITIAL WAVE OF MIXED WINTRY PRECIP HAS EXITED THE FORECAST AREA...WITH SEVERAL EARLIER REPORTS OF SLICK SPOTS/SLIDE-OFFS ACROSS SE OK/WCNTRL AR. NEXT ROUND OF WINTER PRECIP IS CURRENTLY ORGANIZING ACROSS NRN TX...AND PRECIP WILL BEGIN TO EXPAND TO THE ENE OVERNIGHT AS ISENTROPIC LIFT (MOST NOTABLY ALONG 300K SFC ATOP DRY LAYER) INCREASES. SFC TEMPS ACROSS THE ADVISORY AREA ARE CURRENTLY RUNNING AROUND 28-32F...ALTHOUGH T/TD SPREADS SUGGEST SOME WET-BULBING IS LIKELY ONCE PRECIP INCREASES IN COVERAGE/INTENSITY. CURRENT FORECAST IS IN REASONABLE ENOUGH SHAPE...BUT HAVE BUMPED UP POPS ACROSS THE SE AFTER 09Z...MORE IN-LINE WITH LATEST HRRR OUTPUT. PRECIP MAY START AS RAIN/SLEET ACROSS FAR SE OK...WITH A CHANGEOVER TO SLEET...FREEZING RAIN AND POSSIBLY SOME SNOW LATER TONIGHT. TRAVEL IMPACTS WILL MAINLY BE ON ELEVATED ROAD SURFACES...BUT WILL NEED TO CLOSELY MONITOR SE OK. UPDATED PRODUCTS OUT SHORTLY. && .PRELIMINARY POINT TEMPS/POPS... TUL 27 36 26 43 / 40 30 10 0 FSM 29 35 30 44 / 60 60 20 10 MLC 28 35 27 42 / 60 60 20 10 BVO 26 37 24 42 / 20 30 10 0 FYV 26 34 25 40 / 40 50 20 10 BYV 26 34 25 39 / 10 30 20 10 MKO 27 35 26 42 / 50 50 10 10 MIO 27 36 24 41 / 10 20 10 0 F10 26 35 26 41 / 60 40 10 10 HHW 29 35 31 43 / 80 90 40 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR OKZ049-OKZ053- OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076. AR...WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR ARZ019-ARZ020- ARZ029. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...14
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
325 PM CST MON NOV 25 2013 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850 MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES. WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND 0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS 925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING. HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN REMAINS COLD. .LONG TERM...THURSDAY THROUGH SUNDAY NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT. DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA. EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE PACIFIC NORTHWEST. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS A STRATUS DECK CONTINUES TO MOVE SOUTHEAST OUT OF NORTH DAKOTA AND ACROSS NORTHEAST SOUTH DAKOTA. CIGS ARE CURRENTLY IN THE VFR CATEGORY AT KABR AND KATY...ALTHOUGH MVFR CIGS ARE FORECAST FOR KATY OVERNIGHT. FLURRIES ARE ALSO POSSIBLE AT KABR AND KATY OVERNIGHT...HOWEVER DUE TO LOW AREAL COVERAGE AND LITTLE OR NO VSBY RESTRICTIONS...DID NOT ADD LIGHT SNOW INTO THE TAF FORECAST FOR NOW. GUSTY NORTHWEST WINDS THIS AFTERNOON WILL DECREASE TO THE 10 TO 15 KT RANGE OVERNIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...TMT LONG TERM...SERR AVIATION...SERR WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS BLACKSBURG VA
802 PM EST TUE NOV 26 2013 .SYNOPSIS... A DEEP AREA OF LOW PRESSURE WILL TRACK ACROSS THE CAROLINAS TONIGHT AND INTO NEW ENGLAND BY LATE WEDNESDAY...BRINGING HEAVY RAINFALL AHEAD OF IT...WITH A STRONG COLD PUSH AND CHANGE OVER TO SNOW ON THE BACK SIDE BY LATE TONIGHT AND INTO WEDNESDAY AND WEDNESDAY EVENING. STRONG WINDS WILL CAUSE SOME BLOWING OF SNOW LATER WEDNESDAY...ESPECIALLY AT THE HIGHER ELEVATIONS. CHILLY TEMPERATURES WILL FOLLOW THIS WEATHER SYSTEM FOR THURSDAY AND INTO FRIDAY. BY THE WEEKEND...HIGH PRESSURE WILL BUILD INTO THE REGION WITH MODERATING TEMPERATURES. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 755 PM EST TUESDAY... UPDATE TO DROP THE HIGH WIND WARNING FOR THE HIGHEST ELEVATIONS ALONG THE BLUE RIDGE THIS EVENING. THIS BASED ON CURRENT OBS WHICH SHOW THE WEDGE COOL POOL STILL HOLDING WITH BOTH THE VAD PROFILE AND EVENING SOUNDING INDICATING STRONG SOUTH WINDS UP ABOVE 6K FEET WHERE THE WARM NOSE RESIDES. LATEST MODELS KEEP THIS SETUP IN PLACE THIS EVENING SO DROPPING THE WARNING ESPCLY GIVEN MOST SITES ALONG THE PARKWAY SHOWING LIGHT NW-NE WINDS FOR THE MOST PART. MAY BE ABLE TO ALSO CUT THE FLOOD WATCH SOON AS SEEING A LARGE DRY SLOT INVADE THE AREA CURRENTLY WITH THE LATEST HRRR ONLY BRINGING BACK SOME SHOWERS ALONG THE BLUE RIDGE AFTER MIDNIGHT JUST AHEAD OF THE BOUNDARY TO THE WEST. PREVIOUS DISCUSSION AS OF 415 PM EST TUESDAY... DEEPENING LOW PRESSURE TO SLIDE UP ACROSS THE CENTRAL CAROLINAS OVERNIGHT WITH STRONG 850 SOUTHERLY JET TO CONTINUE TO ENHANCE UPSLOPE PRECIP ALONG BLUE RIDGE BEFORE DRY SLOT COMES IN LATER THIS EVENING. THIS COULD ALSO RESULT IN SOME VERY STRONG WINDS AT HIGHER ELEVATIONS ALONG BLUE RIDGE...BUT WONT LAST LONG. CONCERN IS TREES BEING UPROOTED EVEN IF WINDS DO NOT REACH WARNING CRITERIA...AND WOULD ONLY BE THE HIGHEST RIDGES...BUT DECIDED TO PUT A HIGH WIND WARNING OUT THROUGH THIS EVENING JUST IN CASE. RAINFALL AMOUNTS HAVE BEEN ANYWHERE FROM AN INCH TO 3 AND A HALF INCHES SO FAR...BUT NO REPORTS OF FLOODING. ANOTHER INCH OR SO POSSIBLE THROUGH THIS EVENING BEFORE DRY SLOT COMES IN...AND RATES AFTER THAT LATE TONIGHT NOT LIKELY TO CAUSE ADDITIONAL PROBLEMS...BUT HAVE CONTINUED FLOOD WATCH FOR FLOODING OF SMALL STREAMS AND CREEKS THROUGH 6AM...BUT WILL LIKELY BE ABLE TO DROP THAT EARLY. BY THE TIME THE DEEPER COLD AIR WRAPS IN AROUND BEHIND THE EXITING LOW WELL AFTER MIDNIGHT AND INTO WED MORNING...THE HEAVIER PRECIP WILL BE WELL OFF TO THE EAST AND CONCERNS ABOUT ANY DEFORMATION BANDING ARE LESS...SO SNOWFALL IN THE MOUNTAINS SHOULD BE PRIMARILY IN UPSLOPE REGIONS...BUT SOME SPILL OVER UP TO THE BLUE RIDGE IS LIKELY...YET MINIMAL AMOUNTS. ALSO MODELS CONTINUE TO INDICATE THAT COLD AIR FIRST COMES IN A SHALLOW LAYER...WHICH MIGHT ACTUALLY CHANGE THE RAIN TO SLEET BRIEFLY BEFORE THE CHANGEOVER TO SNOW. THIS MAY LIMIT ACCUMULATIONS SOMEWHAT. THEREFORE...ONLY WENT WITH WARNING CRITERIA SNOW FOR FAR WESTERN UPSLOPE AREAS...BUT DECIDED TO INCLUDE THOSE ENTIRE COUNTIES IN THE WARNING DUE TO THE WINDS ALSO BLOWING THE SNOW...AND THE IMPACT DUE TO HIGH TRAVEL DAY AND MUCH OF IT STARTING IN THE MORNING. WENT WITH ADVISORIES UP TO THE BLUE RIDGE AND EVEN ROANOKE AND SHENANDOAH VALLEYS FOR SAME REASON...DESPITE EXPECTED AMOUNTS BEING BELOW CRITERIA FOR ADVISORY. JUST AN INCH OR SO OF SNOW ON THE INTERSTATES THIS PARTICULAR DAY...SO EARLY IN THE SEASON...AND ALSO WITH WIND WHICH MAY BLOW SOME OF THE DRIER SNOW LATER IN THE DAY AROUND...MAY RESULT IN MUCH GREATER IMPACT THAN MIGHT OTHERWISE BE EXPECTED. SOME NW WINDS ON HIGHER RIDGES COULD REACH WARNING CRITERIA ON WED BUT DECIDED TO LEAVE THOSE JUST BELOW CRITERIA AND INCLUDED WITH WINTER WEATHER PRODUCTS RATHER THAN SEPARATE WIND WARNINGS OR WIND ADVISORIES...EXCEPT FOR FOOTHILLS WHERE THERE ARE NO WINTER HEADLINES. AGAIN...BLOWING SNOW WILL NOT BE AN ISSUE UNTIL MID TO LATE IN THE DAY WHEN SNOW BECOMES DRIER AS COLDER AIR CONTINUES TO FILTER IN AND WINDS PICK UP. SNOW AMOUNTS EAST OF THE UPSLOPE AREAS OF FAR WEST MAY END UP A LITTLE LESS THAN CURRENT FORECAST... BUT AM STILL CONCERNED ABOUT IMPACT WITH EVEN A LITTLE SNOW AND ALL THE TRAVELERS...WITH THE ADDITIONAL POTENTIAL FOR TREES TO GO DOWN WITH ALL THE WET GROUND RESULTING POWER OUTAGES AND COLD TEMPERATURES BEHIND THIS SYSTEM. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 230 PM EST TUESDAY... WEDNESDAY NIGHT...THE AXIS OF THE MAIN UPPER TROUGH WILL MOVE THROUGH THE AREA. ON THE BACKSIDE OF THE TROUGH...A STRONG PRESSURE GRADIENT WILL CONTINUE INTO THE EVENING HOURS. WE ARE LOOKING AT ABOUT A 9.5 MB PRESSURE GRADIENT ACROSS THE FORECAST AREA DURING THE EVENING ALONG WITH 850 MB WINDS RANGING FROM 45 TO 55 KT FROM THE NORTHWEST. AS THE NIGHT PROGRESSES...THE PRESSURE GRADIENT WILL SLACKEN...BUT WE ARE STILL EXPECTING A HEALTHY 30 TO 40 KTS AT 850 MB AND A 5 MB PRESSURE GRADIENT ACROSS THE REGION AT DAYBREAK THANKSGIVING MORNING. THE RESULT SHOULD BE WIND GUSTS ACROSS THE MOUNTAINS WEDNESDAY EVENING IN AT LEAST WIND ADVISORY CRITERIA LEVELS WITH HIGH WIND WARNING CRITERIA POSSIBLE AT ELEVATIONS AT OR ABOVE 3500 FEET MSL. BY SUNRISE THANKSGIVING MORNING...GUSTS AT HIGHER ELEVATIONS WILL HAVE DECREASED TO AROUND 30 TO 35 MPH. ACROSS THE PIEDMONT...WIND SPEEDS WILL BE WEAKER THAN IN MOUNTAINS. WEDNESDAY EVENING GUSTS AROUND 25 MPH WILL BE COMMON. SPEEDS WILL DECREASE THROUGH THE NIGHT AND BE LIGHT FROM THE NORTHWEST THANKSGIVING MORNING. WITH SUCH STRONG NORTHWEST WINDS...THE UPSLOPE SNOW MACHINE WILL BE IN FULL OPERATION WEDNESDAY NIGHT. THE PREFERRED UPSLOPE REGIONS OF SOUTHEAST WEST VIRGINIA AND THE NORTHERN MOUNTAINS OF NORTH CAROLINA SHOULD SEE A LITTLE BE MORE MEASURABLE SNOW. UP TO AN ADDITIONAL TWO INCHES WILL BE POSSIBLE IN THESE AREAS. COVERAGE AND INTENSITY WILL GRADUALLY DECREASE THROUGHOUT THE NIGHT. ADDITIONAL SCATTERED SNOW SHOWERS WILL BE POSSIBLE BETWEEN THESE TWO REGIONS...AND FLURRIES WILL BE POSSIBLE EAST TO THE CREST OF THE BLUE RIDGE...ESPECIALLY DURING THE EVENING HOURS. EAST OF THE CREST OF THE BLUE RIDGE...THE STRONG NORTHWEST FLOW WILL HAVE A DOWNSLOPING IMPACT WHICH WILL HELP TO GREATLY LIMIT THE AMOUNT OF CLOUD COVER. LOW TEMPERATURES WILL RANGE FROM 10 TO 20 ACROSS THE MOUNTAINS WITH LOWER 20S EAST OF THE BLUE RIDGE. WITH THESE LOW TEMPERATURES AND THE GUSTY WINDS...WIND CHILLS ACROSS THE MOUNTAINS WILL FALL INTO THE SINGLE DIGITS WITH TEENS ACROSS THE PIEDMONT. THE HIGHER TERRAINS OF SOUTHEAST WEST VIRGINIA MAY SEE WIND CHILLS AROUND WIND CHILL ADVISORY LEVELS...FIVE BELOW ZERO. FOR THANKSGIVING DAY...THE PRESSURE GRADIENT WILL CONTINUE TO WEAKEN AND THE WIND DIRECTION BECOMES LESS FAVORABLE FOR UPSLOPE SNOW SHOWERS. LOOK FOR UPSLOPE SNOW SHOWERS TO END BY NOON...AND WINDS IN GENERAL BECOME WEAKER. EARLY MORNING WIND CHILLS WILL BE COMPARABLE TO THOSE OF LATE WEDNESDAY NIGHT...BUT SHOULD RISE QUICKLY BOTH AS WIND SPEEDS DECREASE AND TEMPERATURES RISE. HIGH TEMPERATURES WILL RANGE FROM AROUND 30 TO THE MID 30S IN THE MOUNTAINS WITH UPPER 30S TO LOWER 40S ACROSS THE PIEDMONT. CLOUD COVER WILL GRADUALLY DECREASE ACROSS THE MOUNTAINS THROUGHOUT THE DAY. THURSDAY NIGHT THROUGH FRIDAY NIGHT...HIGH PRESSURE WILL BUILD OVER THE REGION...AND ALOFT...AND UPPER RIDGE WILL START TO BUILD OVER THE MISSISSIPPI RIVER VALLEY. FOR OUR AREA THIS WILL YIELD A PRECIPITATION FREE FORECAST. TEMPERATURES WILL BEGIN TO MODERATE ON FRIDAY AS THE CENTER OF THE HIGH STARTS SHIFTING EAST OF THE AREA AND HEIGHTS START TO RISE WITH THE RIDGE BUILDING TO OUR WEST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 PM EST TUESDAY... LOOKING AT RELATIVELY ZONAL FLOW IN THE UPPER LEVELS THROUGH THE WEEKEND...WITH WEAK DISTURBANCES EMBEDDED WITHIN THE PATTERN TO PASS ACROSS OUR AREA. HIGH PRESSURE WILL BECOME FIRMLY WEDGED AGAINST THE EASTERN FACE OF THE BLUE RIDGE SATURDAY MORNING...PROVIDING A LIGHT NORTH TO NORTHEASTERLY WIND ACROSS THE PIEDMONTS...WHILE THE MOUNTAINS CAN EXPECT SOUTHEASTERLY UPSLOPE FLOW. EXPECT DRY CONDITIONS WITH MOSTLY CLEAR SKIES FOR SATURDAY...WITH AFTERNOON HIGHS CLIMBING INTO THE UPPER 30S WEST TO THE LOW 40S EAST. FOR SUNDAY...THE ECMWF MODEL DEVELOPS A LOW PRESSURE SYSTEM ACROSS THE CAROLINAS AS A WEAK UPPER TROUGH MOVES ACROSS THE CENTRAL APPALACHIANS...BRINGING LIGHT RAIN INTO OUR AREA. THE GFS MODEL ON THE OTHER HAND IS SLOWER AND LESS BULLISH WITH THIS DISTURBANCE... AND IS INDICATING LITTLE TO NO RAIN. TRENDING MORE TOWARD THE GFS SOLUTION FOR NOW...BUT WILL NOT TOTALLY DISCOUNT THE ECMWF AND WILL LEAVE MENTION OF A SLIGHT CHANCE OF RAIN FOR THE FORECAST. ON MONDAY...BOTH MODELS DEVELOP A DEEPER LOW OFF THE MID ATLANTIC COAST AS AN UPPER LEVEL TROUGH APPROACHES FROM THE WEST...HOWEVER BOTH MODELS ALSO KEEP MOST PRECIPITATION OFF THE COAST. WILL HOLD ON TO A CHANCE FOR RAIN FOR NOW TO GIVE THE MODELS TIME TO GAIN BETTER FOCUS ON THIS SYSTEM. AS THE UPPER TROUGH DOES NOT APPEAR PARTICULARLY DEEP AND TEMPERATURES WITHIN THE LOWEST FEW THOUSAND FEET OF THE SURFACE APPEAR TO BE SLIGHTLY ABOVE FREEZING...WITH CALL FOR MAINLY RAIN FOR NOW. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... AS OF 700 PM EST TUESDAY... RADAR INDICATES THE RAIN SHIELD WHICH HAS AFFECTED THE FORECAST REGION THROUGH THE DAY IS SHIFTING NORTH OF THE AREA THIS EVENING...WITH DRIER AIR WORKING ITS WAY IN FROM THE WEST. EXPECT RAIN TO DIMINISH ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST THROUGH THE EVENING. LOW PRESSURE WILL MOVE RAPIDLY NORTH ALONG THE COAST PLAIN THROUGH THE NIGHT...WITH WINDS AT ALL TAF SITES SHIFTING NORTHWESTERLY BY AROUND 04Z AS THIS OCCURS...DRAWING COLDER AIR INTO THE AREA. THIS WILL CAUSE RAIN TO TURN TO SNOW THROUGH THE NIGHT...POSSIBLY WITH A BRIEF PERIOD OF FREEZING RAIN OR SLEET. MOST AFFECTED WILL BE LWB AND BLF...WHERE SNOW SHOWERS WILL LIMIT VISIBILITY AT TIMES TO A MILE OR LESS. SNOW SHOWER ACTIVITY WILL DIMINISH IN INTENSITY FURTHER EAST...BUT MAY SEE STREAMERS OF SNOW OFF THE WESTERN RIDGES MAKE IT AS FAR AS ROA AND LYH...BRINGING VISIBILITIES AT THESE TAF SITES TO IFR AS WELL. REGARDLESS...WITH THE WIND SHIFT...EXPECT CEILINGS TO REMAIN BELOW 1 KFT THROUGH 12Z AT ALL TAF SITES...WITH GRADUAL IMPROVEMENT FROM EAST TO WEST THEREAFTER. BY 21Z...CEILINGS AT MOST TAF SITES ARE EXPECTED TO IMPROVE TO LOW END VFR OR HIGH MVFR EXCEPT BLF...WHICH IS EXPECTED TO REMAIN IFR INTO THURSDAY DUE TO STRONG UPSLOPE FLOW IN THE LOCAL TERRAIN. THE OTHER MAIN CONCERN WILL BE STRONG NORTHWEST WINDS AS THE SYSTEM PASSES UP THE COAST. BY 12Z...THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN TO AROUND 9MB ACROSS THE REGION...SUPPORTING SURFACE WIND GUSTS IN THE 25KT TO 30KT RANGE THROUGH THE DAY...POSSIBLY AS HIGH AS 35KT AT ROA. CROSS BARRIER FLOW WILL ALSO RESULT IN MODERATE TO SEVERE LOW LEVEL TURBULENCE ACROSS THE AREA. WIND SPEEDS WILL GRADUALLY DIMINISH AFTER 21Z...AS HIGH PRESSURE APPROACHES FROM THE WEST. HIGH PRESSURE WILL SETTLE ACROSS THE AREA FOR THANKSGIVING DAY...BECOMING WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE WEEKEND...RESULTING IN A PROLONGED PERIOD OF VFR CONDITIONS. && .HYDROLOGY... AS OF 1130 AM EST TUESDAY... STILL IN THE OPENING STAGES OF WHAT LOOKS TO BE A FAIRLY COMPLEX HYDRO EVENT. 24-HOUR LIQUID AMOUNTS THROUGH 12Z WERE QUITE MODEST...GENERALLY 0.25 TO 0.50 INCHES ACROSS THE SOUTHERN HALF OF THE CWA. THE NEXT 24 HOURS WILL FEATURE HEAVY RAINFALL..THAT MUCH SEEMS ASSURED WITH ONGOING RAINFALL AND TREMENDOUS MOISTURE TRANSPORT FORECAST ACROSS THE BLUE RIDGE AND FOOTHILLS. MOISTURE TRANSPORT ANOMALIES UP TO 5 STANDARD DEVIATIONS SHOWN BY THE NAM DURING PORTIONS OF THE NEXT 24 HOURS WHICH RAISES SOME ALARMS. BUFKIT FORECAST SOUNDING SHOW PWAT 1.4 TO 1.6 AT KGSO BY 00Z THIS EVENING WHICH IS CLOSE TO 99TH PERCENTILE OF BUNKERS CLIMO FOR PWAT THERE. SO TOTAL QPF IN THE 2 TO 4 INCH RANGE STILL SEEMS QUITE LIKELY BY TONIGHT WITH HIGHER AMOUNTS FOCUSED ALONG THE FAVORED UPSLOPE AREAS OF THE BLUE RIDGE. HOWEVER THIS DOES NOT APPEAR TO BE MAINSTEM RIVER FLOOD PROBLEM AT THIS POINT GIVEN THE RIVER FORECAST CENTER GUIDANCE FROM ALL OF THE FOUR RFCS AS OF 12Z THIS MORNING. NONE OF OUR FORECAST POINTS FROM ANY RFC ARE DRIVEN TO FLOOD STAGE WITH THE CURRENT QPF WHICH RANGES FROM 2 TO 3 INCHES ACROSS NEARLY ALL THE BASINS BY 18Z TOMORROW 11/27 WHICH WILL COMPRISE THE PERIOD OF HYDROLOGICALLY SIGNIFICANT RAINFALL. RIVERS WILL OBVIOUSLY BE ON THE RISE AND A FEW MAY APPROACH BANKFULL OR ACTION STAGE (GENERALLY A FEW FEET BELOW FLOOD STAGE). BUT THE EXTREMELY DRY ANTECEDENT CONDITIONS OF THE PAST 2 MONTHS ARE CLEARLY A MITIGATING FACTOR IN THE RIVER FLOOD FORECASTS. STILL WILL HAVE TO CLOSELY MONITOR RIVER TRENDS VERSUS THE FORECAST ONCE RIVERS BEGIN TO RESPOND AS HYDROLOGIC MODELS OFTEN STRUGGLE IN HANDLING THE RUNOFF OF HEAVY RAINFALL AFTER AN EXTENDED DRY PERIOD SUCH AS WE HAVE EXPERIENCED. YET HYDROLOGIC ISSUES ON SMALLER BASINS MAY STILL OCCUR DUE TO SEVERAL FACTORS. ALTHOUGH RAINFALL RATES WILL NOT BE PARTICULARLY HIGH THEY WILL GENERALLY RANGE FROM 0.10 TO 0.25 INCHES PER HOUR FOR AN EXTENDED DURATION AND THERE IS SOME POSSIBILITY OF ELEVATED CONVECTION (ALTHOUGH MAINLY EAST OF CWA) WHICH COULD BUMP RATES UP CLOSER TO 1 INCH PER HOUR. IT MAY BE DIFFICULT TO EXCEED FFG VALUES IN THE 1-HR AND 3-HR TIME FRAMES BUT 6-HR FFG RANGES FROM 2.5 TO 3.5 INCHES AND COULD BE LOCALLY EXCEEDED IN SOME AREAS. THIS FALLING ON TOP OF WHAT MAY BE A SATURATED SURFACE LAYER COULD EASILY LEAD TO POCKETS OF AT LEAST MINOR FLOODING. FALL DEBRIS CAN BE QUITE EFFECTIVE IN PRODUCING CULVERT BLOCKAGES WHICH CAN ALSO CAUSE MINOR FLOODING ON ROADWAYS WHERE RUNOFF IS BLOCKED. FOR THESE REASONS A FLOOD WATCH WILL BE ISSUED THROUGH 6AM BUT MORE FOR SMALL STREAM AND ROADWAY FLOODING THAN FOR RIVER FLOODING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR VAZ010>014-016>020-022>024. FLOOD WATCH UNTIL 6 AM EST WEDNESDAY FOR VAZ014>017-022>024- 032>035-043. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM EST WEDNESDAY FOR VAZ007-009-015. WIND ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR VAZ032>035. NC...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR NCZ002. FLOOD WATCH UNTIL 6 AM EST WEDNESDAY FOR NCZ001>004-018>020. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM EST WEDNESDAY FOR NCZ001-018. WIND ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR NCZ003-019. WV...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR WVZ044. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 1 AM EST THURSDAY FOR WVZ042-043-045. && $$ SYNOPSIS...RAB/SK NEAR TERM...JH/SK SHORT TERM...DS LONG TERM...NF AVIATION...JC/NF HYDROLOGY...PC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1110 AM CST MON NOV 25 2013 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND TUESDAY ISSUED AT 406 AM CST MON NOV 25 2013 PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT. WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTH CENTRAL WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING REPORTED. MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA. SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT 17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF THIS DOES OCCUR...WILL HANDLE WITH SPS. GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH SOMEWHAT THEREAFTER. NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW SHOWER ACTIVITY ESPECIALLY ACROSS NORTH-CENTRAL WISCONSIN TUESDAY. MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340 DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND 18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360 DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT. .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY ISSUED AT 406 AM CST MON NOV 25 2013 UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND. LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY. THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY. LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION SHOULD BE MINOR. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1055 AM CST MON NOV 25 2013 FIRST BAND OF LIGHT SNOW SHIFTED EAST OF THE AREA THIS MORNING WITH MVFR CIGS LINGERING ACROSS THE AREA. CIGS SHOULD RISE INTO THE VFR CATEGORY LATER THIS AFTERNOON AND THIS EVENING. ATTENTION THEN TURNS TO REINFORCING SHOT OF COLD AIR WITH ARCTIC COLD FRONT THAT WILL SWEEP ACROSS THE AREA LATER TONIGHT INTO TUESDAY MORNING. EXPECT A BAND OF LIGHT SNOW OR FLURRIES / MVFR CIGS ALONG THE FRONT...AS NOTED ACROSS THE NORTHERN PLAINS LATE THIS MORNING. HAVE TRIED TO TIME THE LIGHT SNOW IN THE 18Z TAFS. VISIBILITIES FOR A BRIEF PERIOD OF TIME MAY BE EVEN LOWER THAN WHAT IS IN THE FORECAST AT EACH TAF SITE. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....ESB LONG TERM......MG AVIATION.......ECKBERG
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
613 AM CST MON NOV 25 2013 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND TUESDAY ISSUED AT 406 AM CST MON NOV 25 2013 PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT. WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTHCENTRAL WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING REPORTED. MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA. SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT 17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF THIS DOES OCCUR...WILL HANDLE WITH SPS. GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH SOMEWHAT THEREAFTER. NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW SHOWER ACTIVITY ESPECIALLY ACROSS NORTHCENTRAL WISCONSIN TUESDAY. MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340 DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND 18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360 DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT. .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY ISSUED AT 406 AM CST MON NOV 25 2013 UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND. LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY. THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY. LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION SHOULD BE MINOR. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 611 AM CST MON NOV 25 2013 AN UPPER-LEVEL DISTURBANCE AND ASSOCIATED SURFACE TROUGH WILL GENERATE A BRIEF PERIOD OF LIGHT SNOW POSSIBLY MIXED WITH SOME LIGHT FREEZING DRIZZLE THROUGH ABOUT 14Z AT GRB AND ATW TAF SITES. MAINLY MVFR CIGS AND VSBYS EXPECTED IN THE HEAVIER SNOW SHOWERS. PRECIPITATION SHOULD EXIT THE FOX VALLEY BY 15Z...AND WILL BE FOLLOWED BY AREAS OF MVFR CIGS THROUGH ABOUT 20Z. STRONG SOUTHWEST WINDS GUSTING TO 30KTS AND LLWS SHOULD DIMINISH AFTER 15Z AS PRESSURE GRADIENT RELAXES WITH APPROACHING SURFACE TROUGH. GENERALLY VFR CONDITIONS OVERNIGHT...EXCEPT ACROSS NORTHERN WISCONSIN WHERE MVFR CIGS AND VSBYS ARE POSSIBLE AS ANOTHER UPPER-LEVEL DISTURBANCE APPROACHES IN CONCERT WITH INCREASING LAKE EFFECT SNOW BANDS OFF LAKE SUPERIOR. THE SNOW SHOWER ACTIVITY WILL BE MOST NUMEROUS OVER VILAS COUNTY AFTER MIDNIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....ESB LONG TERM......MG AVIATION.......ESB
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY ISSUED AT 406 AM CST MON NOV 25 2013 PRIMARY FOCUS OF SHORT-TERM FORECAST WILL BE LIGHT PRECIPITATION ASSOCIATED WITH A COUPLE RATHER POTENT NORTHERN STREAM SHORTWAVE DISTURBANCES DIVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES...AND INCREASING LES POTENTIAL ACROSS THE LAKE SUPERIOR SNOWBELT. WATER VAPOR IMAGERY SHOWS FIRST SHORTWAVE DISTURBANCE HEADING SOUTHEAST TOWARD LAKE SUPERIOR EARLY THIS MORNING. PRIMARY SYNOPTIC FORCING WITH THIS FEATURE TO REMAIN NORTH OF THE FORECAST AREA TODAY. FORCING RATHER LACKLUSTER FURTHER SOUTH ASSOCIATED WITH WEAK SURFACE TROUGH HEADING SOUTHEAST ACROSS MINNESOTA. 00Z SOUNDINGS AT MPX...GRB AND ILX ONCE AGAIN SUGGEST RATHER PALTRY DEEP LAYER MOISTURE TO WORK WITH AHEAD OF THIS SYSTEM. THUS AS INDICATED IN LATEST RADAR DATA...HAVE ONLY BEEN ABLE TO GENERATE BAND OF VERY WEAK RADAR RETURNS EXTENDING FROM NORTHCENTRAL WISCONSIN TO SOUTHWEST MINNESOTA. LITTLE OR NO PRECIPITATION ASSOCIATED WITH THIS FEATURE THUS FAR WITH JUST FLURRIES BEING REPORTED. MEANWHILE FURTHER SOUTH...WHERE ANOTHER VERY WEAK IMPULSE...WEAK FRONTOGENETIC FORCING AND SLIGHTLY DEEPER MOISTURE EXIST...SCATTERED TO BROKEN SNOW SHOWER ACTIVITY HAS BROKEN OUT OVER EASTERN IOWA. SHORT RANGE MODEL GUIDANCE SUGGEST THAT THIS ACTIVITY WILL MOVE ENE AND AFFECT MAINLY THE SOUTHERN THIRD OF THE FORECAST AREA THIS MORNING. BASED ON LATEST OBSERVATIONS APPEARS MOISTURE IS DEEP ENOUGH TO GENERATE ICE CRYSTALS RESULTING IN MAINLY SNOW RATHER THAN FREEZING DRIZZLE. GIVEN THE POORLY ORGANIZED AND WEAK FORCING...AND UNCERTAINTY IN AVAILABLE MOISTURE OVER THE FORECAST AREA THIS MORNING...OPTED TO KEEP A MIX OF VERY LIGHT SNOW AND/OR FREEZING DRIZZLE GOING FOR THE ENTIRE FORECAST AREA THROUGH ABOUT 17Z. GIVEN LATEST RADAR TRENDS AND HRRR FORECAST...APPEARS BEST CHANCE FOR LIGHT MEASURABLE PRECIPITATION WILL BE OVER THE FOX VALLEY THIS MORNING...THUS KEPT HIGHEST POPS THERE. WILL CONTINUE TO MONITOR RADAR TRENDS AND SURFACE OBSERVATIONS ACROSS THIS AREA AS THERE STILL IS POTENTIAL FOR SUFFICIENT LIGHT SNOW OR LIGHT FREEZING DRIZZLE TO CREATE A FEW SLICK SPOTS DURING THE MORNING COMMUTE. IF THIS DOES OCCUR...WILL HANDLE WITH SPS. GUIDANCE ALSO SUGGESTS THAT SURFACE PRESSURE GRADIENT WILL BE STRONGEST BETWEEN NOW AND ABOUT 15Z...AND WILL BEGIN TO RELAX THEREAFTER AS SURFACE TROUGH SWINGS THROUGH THE AREA AROUND MIDDAY. THUS EXPECT RATHER STRONG SOUTHWEST WINDS TO CONTINUE TO GUST INTO THE 30-35 MPG RANGE THROUGH MID-MORNING AND DIMINISH SOMEWHAT THEREAFTER. NEXT AND SOMEWHAT MORE POTENT SHORTWAVE THEN IMPINGES ON THE FORECAST AREA TOWARD DAYBREAK TUESDAY. FEEL LARGE-SCALE FORCING WILL BE A BIT MORE ROBUST SUCH THAT MAY SEE MORE WIDESPREAD SNOW SHOWER ACTIVITY ESPECIALLY ACROSS NORTHCENTRAL WISCONSIN TUESDAY. MORE IMPORTANTLY...AS THIS SYSTEM MOVES ACROSS NORTHERN WISCONSIN TUESDAY MORNING...BOUNDARY LAYER WINDS WILL VEER TO FAVORABLE 340 DEGREE DIRECTION OVER WESTERN LAKE SUPERIOR TO INITIATE LES BANDS ONCE AGAIN. GIVEN RATHER IMPRESSIVE SHORTWAVE PASSING THROUGH THIS AREA...FAVORABLE FETCH AND OVER WATER INSTABILITY...ACCUMULATING SNOWS SEEM LIKELY ACROSS NORTHWEST VILAS COUNTY STARTING AROUND 18Z TUESDAY AND CONTINUING INTO TUESDAY NIGHT. HOWEVER MODELS DO SUGGEST BOUNDARY LAYER WINDS WILL VEER TO A LESS FAVORABLE 360 DEGREES BY 06Z WEDNESDAY. WILL LET DAY-SHIFT TAKE A CLOSER LOOK AT THE LES POTENTIAL FOR LATER TUESDAY INTO TUESDAY NIGHT...BUT WOULD NOT BE SURPRISED TO SEE ADVISORY HOISTED AT SOME POINT. .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY ISSUED AT 406 AM CST MON NOV 25 2013 UPPER LEVEL FLOW ACROSS THE NORTHERN CONUS IS FORECAST TO BECOME LESS AMPLIFIED/MORE ZONAL BY THE END OF THE WEEK. THIS WILL RESULT IN THE THERMAL TROUGH...THAT SHOULD BE OVER THE AREA TUESDAY NIGHT...SHIFTING EAST OF WISCONSIN. WARM ADVECTION LATER DURING THE WEEK WILL BRING NEAR NORMAL HIGH TEMPERATURES BY THE WEEKEND. LAKE EFFECT SHOULD COME TO AN END IN THE FORECAST AREA BY WEDNESDAY AFTERNOON AS A SURFACE RIDGE REACHES THE STATE. SNOW WITH THE NEXT CLIPPER SYSTEM SHOULD REMAIN NORTH OF THE STATE...SO ONLY SOME SLIGHT CHANCES FOR SNOW IN THE FAR NORTH ON THURSDAY. THE NEXT SYSTEM AFTER THAT IS EXPECTED TO PUSH FARTHER SOUTH AND BRING A CHANCE FOR SNOW SHOWERS TO NORTHERN WISCONSIN ON SATURDAY. LITTLE MOISTURE WILL ACCOMPANY THESE SYSTEMS SO ANY ACCUMULATION SHOULD BE MINOR. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 406 AM CST MON NOV 25 2013 UPPER DISTURBANCE WILL GENERATE SOME VERY LIGHT SNOW OR PERHAPS SOME LIGHT FREEZING DRIZZLE THIS MORNING. DO NOT EXPECT THIS PRECIPITATION TO HAVE MUCH IMPACT ON VSBYS. AS WEAK SURFACE TROUGH PASSES SOUTHEAST ACROSS THE FORECAST AREA TOWARD MID- DAY...MVFR CIGS WILL FOLLOW. GUSTY SOUTHWEST WINDS AND LLWS SHEAR WILL DIMINISH LATER THIS MORNING AS PRESSURE GRADIENT RELAXES WITH APPROACH OF THE SURFACE TROUGH. SCT-BKN MVFR CIGS EXPECTED ON TUESDAY AS MORE POTENT UPPER DISTURBANCE MOVES ACROSS THE FORECAST AREA. PERHAPS SOME SCT IFR CIGS AND VSBYS ASSOCIATED WITH HEAVIER SNOW SHOWER ACTIVITY MAINLY NORTH OF RHI. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....ESB LONG TERM......MG AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 PM CST SUN NOV 24 2013 .UPDATE... ISSUED AT 933 PM CST SUN NOV 24 2013 THE MAIN FOCUS TONIGHT HAS BEEN ON THE PRECIPITATION TYPE AND CHANCES OVERNIGHT INTO TOMORROW MORNING. CURRENTLY...THERE IS ONE LEAD MID LEVEL SHORTWAVE TROUGH DROPPING SOUTH ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN WITH ANOTHER SYSTEM IN THE CENTRAL PLAINS. RADAR RETURNS WITH THE MN/WI TROUGH DO NOT APPEAR TO BE REACHING THE GROUND DUE TO SOME DRY LOW TO MID LEVEL AIR THAT IS IN PLACE ACCORDING TO 25.00Z MPX/GRB/ABR RAOBS. THE RADAR RETURNS IN SOUTHWEST IOWA ALSO DO NOT APPEAR TO BE REACHING THE GROUND AS WELL THANKS TO THIS DRY LOW LEVEL AIR. SO...WHILE CLOUD COVER WILL BE ON THE INCREASE...IT APPEARS THAT THE REST OF THE EVENING WILL BE DRY. THE MAIN CHANCES FOR ANY PRECIPITATION LOOKS TO BE BETWEEN 3AM AND 9AM TOMORROW MORNING AS THESE TWO SYSTEMS CONVERGE ON THE AREA. HAD HOPED TO HAVE A BETTER HANDLE ON WHETHER THERE WILL BE ICE PRESENT AS THE LIFT COMES IN...BUT THE PAST FEW RUNS OF THE RAP HAVE GONE BACK AND FORTH ON WHETHER THERE WILL BE ANY ICE. THIS LEADS TO CONFIDENCE NOT BEING HIGH ENOUGH TO MOVE FORWARD ON A POTENTIAL ADVISORY FOR FREEZING DRIZZLE SINCE THE POSSIBILITY IS THERE THAT IT WOULD JUST BE A BRIEF PERIOD OF LIGHT SNOW. OTHERWISE...WINDS HAVE REMAINED GUSTY THROUGHOUT THE REGION AS THE PRESSURE GRADIENT IS STILL VERY TIGHT BETWEEN THE RETREATING HIGH OVER THE OHIO RIVER VALLEY AND THE APPROACHING TROUGH IN THE NORTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 201 PM CST SUN NOV 24 2013 MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES LATER TONIGHT...ALONG WITH HOW MUCH AND POTENTIAL FOR FREEZING DRIZZLE. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...SUBTROPICAL STREAM TROUGH OVER ARIZONA...AND NORTHERN STREAM TROUGHING FROM CENTRAL CANADA INTO NEW ENGLAND. WITHIN THIS TROUGHING...A FAIRLY POTENT SHORTWAVE WAS SEEN DIVING SOUTHEAST THROUGH SASKATCHEWAN. AHEAD OF THIS TROUGH...VAD WIND PROFILES DEPICT 30-45 KT 925MB WINDS ACROSS THE EASTERN DAKOTAS AND MINNESOTA. THESE WINDS HAVE BEEN ADVECTING WARMER AIR TOWARDS THE FORECAST AREA...WITH 925MB TEMPS NOW PER RAP ANALYSIS AT -7 TO -12C...COMPARED TO -12 TO -14C AT 12Z. AIRMASS REMAINS RELATIVELY DRY...THOUGH...WITH PRECIPITABLE WATER VALUES JUST BELOW 0.25 INCH ACROSS THE UPPER MIDWEST. UPSTREAM IN THE WAKE OF THE SHORTWAVE...ANOTHER ARCTIC AIR SURGE WAS BREWING ACROSS THE NORTHWEST TERRITORIES WHERE TEMPERATURES ARE SITTING IN THE SINGLE DIGITS AND TEENS ABOVE ZERO. MODELS ARE IN GOOD AGREEMENT SLIDING THE POTENT SHORTWAVE OVER SASKATCHEWAN SOUTHEAST INTO NORTHERN PORTIONS OF MN...WI AND MI MONDAY MORNING...THEN HEADING OFF TO EASTERN ONTARIO DURING THE AFTERNOON. AS THE SHORTWAVE APPROACHES TONIGHT...SFC/925/850MB WINDS ALL INCREASE OVER THE FORECAST AREA...SETTING UP FOR A MUCH WARMER NIGHT. IN ADDITION...THESE WINDS WILL ADVECT IN A TONGUE OF RELATIVELY HIGHER MOISTURE FROM WESTERN KS AND EASTERN COLORADO...AS WELL AS FROM UP IN SOUTHERN MANITOBA...NOTED BY PRECIPITABLE WATER CLIMBING TO AROUND 0.5 INCH. THE HIGHEST PRECIPITABLE WATER IS CONFINED TO NORTHEAST IOWA AND SOUTHERN WI WHICH WOULD THEREFORE BE THE GREATEST CONCERN FOR PRECIPITATION. ALBEIT...THE GENERAL LOW AMOUNT OF PRECIPITABLE WATER WILL LIKELY LIMIT THE AMOUNT OF PRECIPITATION. REGARDING LIFT...280-290K ISENTROPIC SURFACES DEPICT AN INCREASE OF NET ADIABATIC OMEGA ACROSS THE FORECAST AREA BETWEEN 06 AND 12Z...THEN SLIDES OFF TO THE SOUTHEAST. GENERAL MODEL CONSENSUS HAS BEEN HOLDING STEADY SUGGESTING PRECIPITATION BREAKING OUT ACROSS NORTHEAST IOWA LATE TONIGHT...THEN SPREADING INTO SOUTHERN AND PERHAPS CENTRAL WISCONSIN MONDAY MORNING. SINCE SATURATION OCCURS FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE...THE PRECIPITATION TYPE SHOULD BE MOSTLY SNOW...BUT CANNOT RULE OUT SOME FREEZING DRIZZLE POSSIBLE EITHER AT THE ONSET OR ON THE NORTH SIDE OF THE DEEPER MOISTURE. ANOTHER CONCERN IS PRECIPITATION BREAKING OUT ALONG THE POTENT SHORTWAVES WARM FRONT. 24.12Z GFS/HIRESARW AND 24.15Z SREF ALL SUGGEST THAT AS THE FRONT RUNS INTO LOW LEVEL STRATUS WHICH DEVELOPED LATE TONIGHT AHEAD OF IT...VERTICAL MOTION WITH THE FRONT CAN PRODUCE LIGHT PRECIPITATION. THIS WOULD APPEAR TO BE THE BEST CHANCE TO SEE FREEZING DRIZZLE. MUCH OF THE FORECAST AREA WOULD HAVE A CONCERN FOR THIS DEVELOPING...INCLUDING NORTHEAST IA AND SOUTHERN WI WHEN THE SNOW THERE DEPARTS. GIVEN THAT THE PROBABILITY OF FREEZING DRIZZLE IS LOW AT THIS TIME...ON THE ORDER OF 20 TO MAYBE 30 PERCENT...HAVE NOT ISSUED ANY WINTER WEATHER ADVISORIES. FURTHER SHIFTS MAY NEED TO ISSUE THEM...THOUGH...IF FREEZING DRIZZLE LOOKS MORE LIKELY TO OCCUR. TEMPERATURE WISE...WE SHOULD SEE TEMPERATURES HOLD EITHER NEARLY STEADY AND LIKELY RISE AFTER MIDNIGHT AS THE BREEZY SOUTH WINDS BRING IN WARMER AIR AT THE SURFACE. THERE IS POTENTIAL FOR SOME CLEARING MONDAY AFTERNOON...WHICH WITH 925MB TEMPS WARMING TO -2 TO - 4C IN THE AFTERNOON...HIGHS SHOULD CLIMB INTO THE 30S IN MOST LOCATIONS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 201 PM CST SUN NOV 24 2013 FOCUS OF THE LONG TERM PERIOD IS ON AN ARCTIC COOL SHOT SLATED FOR TUESDAY INTO WEDNESDAY...AND ANY POSSIBLE PRECIPITATION THURSDAY INTO THE WEEKEND. MODELS DEPICT ANOTHER POTENT SHORTWAVE DROPPING OUT OF THE NORTHWEST TERRITORIES AND DOWN INTO THE FORECAST AREA ON TUESDAY. THIS POTENT SHORTWAVE REALLY HELPS TO BRING DOWN THE ARCTIC AIR OBSERVED UP THERE. AT THE SAME TIME...WITH THE ARCTIC COLD FRONTAL PASSAGE OCCURRING IN THE MORNING...LOW LEVEL MOISTURE GETS TRAPPED. THIS MOISTURE COMBINED WITH DAYTIME HEATING WILL MANIFEST ITSELF INTO A FAIRLY WIDESPREAD STRATUS DECK. STEEP LOW LEVEL LAPSE RATES ALONG WITH THE STRATUS DECK BEING IN THE DENDRITIC GROWTH ZONE IS LIKELY TO LEAD TO FLURRIES AT A MINIMUM...AND WOULD NOT BE SURPRISED IF SOME LOW CHANCES OF PRECIPITATION WILL NEED TO BE ADDED. WITH THE ARCTIC COLD FRONTAL PASSAGE TUESDAY MORNING...EXPECT TEMPERATURES TO NOT RISE MUCH AND IF ANYTHING WILL LIKELY FALL DURING THE AFTERNOON HOURS. 925MB TEMPS FALL TO -12C BY 00Z WEDNESDAY AND TO AROUND -14C BY 12Z WEDNESDAY. THERE IS A CONTINUING NORTHWEST BREEZE THROUGH THIS PERIOD WHICH WILL TEMPER A BIT ON HOW COLD WE GET TUESDAY NIGHT...AND LEANED MORE TOWARDS THE MET GUIDANCE FOR LOWS. ON THE FLIP SIDE...EXPECT COLDER WIND CHILLS BECAUSE OF THE BREEZE. SOME MODERATION TAKES PLACE IN 925MB TEMPS ON WEDNESDAY WITH SUN SO THAT TEMPERATURES CAN CLIMB BACK INTO THE LOW TO MID 20S. THE UPPER FLOW FROM THANKSGIVING AND BEYOND LOOKS TO CHANGE...GOING FROM THE NORTHWESTERLY PATTERN WE HAVE BEEN IN RECENTLY TOWARDS MORE ZONAL. THERE ARE EVEN HINTS IN THE 24.12Z ECMWF OF THE FLOW BACKING SOUTHWESTERLY EARLY NEXT WEEK. THIS PATTERN CHANGE WILL HELP DISLODGE SOME OF THE COLD AIR...THUS FOLLOWED A CONSENSUS FORECAST DEPICTING A GRADUAL MODERATING TREND FOR TEMPERATURES. REGARDING PRECIPITATION CHANCES...DURING THE PATTERN CHANGE...THERE ARE SHORTWAVE TROUGHS TRAVERSING ACROSS NORTHERN MN INTO UPPER MI ON THANKSGIVING AND ON SATURDAY. RIGHT NOW BASED ON THE TRACK WOULD SUGGEST THE BETTER CHANCES FOR PRECIPITATION WOULD STAY NORTH OF THE FORECAST AREA. HOWEVER...THAT SATURDAY SHORTWAVE TROUGH APPEARS TO TAKE A BIT FARTHER SOUTH TRACK COMPARED TO THE ONE ON THANKSGIVING...THUS 20 PERCENT CHANCES OF SNOW ARE IN THE FORECAST FOR BOTH SATURDAY AND SATURDAY NIGHT. FRIDAY AND SUNDAY APPEAR DRY AT THIS TIME BETWEEN SHORTWAVE TROUGHS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1137 PM CST SUN NOV 24 2013 AS TWO SYSTEMS MERGE ACROSS THE REGION OVERNIGHT INTO MONDAY MORNING...CHANCES FOR PRECIPITATION WILL BE RISE WITH FLIGHT CONDITIONS LOWERING. THE MAIN PERIOD OF CONCERN IS BETWEEN 6AM AND NOON WHEN MOISTURE DEEPENS AND THE LIFT BECOMES STRONGER. CONFIDENCE IS NOT VERY HIGH WITH WHETHER THE POTENTIAL PRECIPITATION TYPE WILL BE SNOW OR FREEZING DRIZZLE...BUT THE CHANCES LOOK HIGHER THAT IT WILL BE FREEZING DRIZZLE AT LSE. RST MAY NOT SEE ANY...SO HAVE TAKEN IT OUT OF THEIR TAF. CEILINGS WILL LIKELY DROP TO MVFR/IFR AS THIS PRECIPITATION STARTS UP MONDAY MORNING. WINDS HAVE REMAINED GUSTY THROUGH THE REGION WITH LOW LEVEL WIND SHEAR CRITERIA LIKELY NOT BEING MET AT RST WITH WINDS GUSTING TO 30-40KTS AT THE SURFACE. CONDITIONS ARE EXPECTED TO IMPROVE INTO MONDAY NIGHT AS DRIER AIR MOVES IN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...AJ LONG TERM...AJ AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1254 AM EST WED NOV 27 2013 .SYNOPSIS... LOW PRESSURE WILL INTENSIFY AND MOVE NORTH-NORTHEAST THROUGH THE MID ATLANTIC STATES OVERNIGHT...THEN PASS OVER THE AREA ON WEDNESDAY...AND THEN ON INTO EASTERN CANADA WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BUILDS IN FROM THURSDAY THROUGH SATURDAY...AND MOVE OFF THE NEW ENGLAND COAST ON SUNDAY. A COASTAL FRONT WILL DEVELOP ON SUNDAY AND REMAIN INTO MONDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT AND MOVE ALONG THE COAST ON TUESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WILL LET WINTER WEATHER ADVISORY EXPIRE AT 1AM IN ORANGE COUNTY...MESONET OBS ONLY SHOW AT MOST A POCKET OR TWO OF TEMPERATURES AT 32 WITH EVERYPLACE OUT 33+ SO AREAL COVERAGE DOES NOT JUSTIFY AN EXTENSION. ON THE WHOLE ONLY MADE MINOR ADJUSTMENTS BASED ON LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. ELSEWHERE...RAIN WILL INCREASE IN INTENSITY OVERNIGHT AS PRIMARY LOW PRESSURE WEAKENS ALONG A LOW LEVEL BAROCLINIC ZONE ALONG THE COASTAL PLAIN...AND GIVES WAY TO A SECONDARY LOW OVER THE MID ATLANTIC FORMING UNDER THE STRENGTHENING RIGHT ENTRANCE REGION OF A DIFFLUENT UPPER JET STREAK APPROACHING FROM THE WEST AS A NORTHERN/SOUTHERN STREAMS PHASE ALOFT. THIS IS EVIDENT IN RAPID PRESSURE FALLS THIS EVENING ACROSS THE DC AREA. A S-SE LOW LEVEL JET WILL INTENSIFY EAST OF THE LOW OVERNIGHT... TRANSPORTING ATLANTIC/GULF MOISTURE INTO THE REGION AND PROVIDING AMPLE LOW LEVEL CONVERGENCE/LIFT FOR HEAVY RAIN. OROGRAPHIC LIFT WILL ALSO COME INTO PLAY NORTH/WEST OF NYC GIVEN THE LOW LEVEL SE FLOW TO START. GIVEN THESE FACTORS THE FLOOD WATCH CONTINUES FOR THE POTENTIAL FOR AREAL/URBAN FLOODING AND FLOODING OF SMALL STREAMS. SEE HYDROLOGY SECTIONS FOR MORE DETAILS. THE LOW LEVEL JET ALSO LOOKS STRONG ENOUGH TO SUPPORT STRONG SE-S WINDS ALONG THE COAST...SO THE WIND ADVISORY CONTINUES. VERY STRONG NAM LOW LEVEL JET WITH 85-95 KT AT H8 MAY LOOK LIKE AN OUTLIER COMPARED TO WEAKER/FARTHER EAST GFS/ECMWF...BUT LATEST RUNS OF THE RAP DO LEND IT SUPPORT SO AM NOT WILLING TO DISCOUNT IT. SFC-H8 INVERSION SHOULD PREVENT THE STRONGEST OF THESE WINDS FROM MIXING DOWN. HOWEVER HAVE A NAGGING CONCERN THAT DUCTED GRAVITY WAVES COULD AID IN DOWNWARD MOMENTUM TRANSPORT TOWARD MORNING PER AKQ RESEARCH...AS WEAK INSTABILITY MOVES IN ALOFT JUST NORTH OF AN APPROACHING WARM FRONT...AND AS THE UPPER JET STREAK APPROACHES THE DOWNSTREAM INFLECTION POINT BETWEEN THE UPPER TROUGH TO THE WEST AND OFFSHORE RIDGING...SO POTENTIAL FOR 60+ MPH WIND GUSTS ACROSS LONG ISLAND AND COASTAL SE CT WILL HAVE TO BE WATCHED. MOST LIKELY SCENARIO WILL BE FOR SUSTAINED WINDS 25-35 MPH WITH GUSTS 45-50 MPH...MAINLY IN/NEAR NYC AND ALONG THE COAST BEGINNING LATE TONIGHT. THERE COULD BE A FEW RUMBLES OF THUNDER LATE AS ELEVATED INSTABILITY MOVES OVER THE AREA. SEE TIDES AND COASTAL FLOODING SECTIONS FOR MINOR COASTAL FLOODING AND BEACH EROSION CONCERNS. TEMPS WILL BE ON THE RISE TONIGHT...REACHING THE MID AND UPPER 50S BY MORNING. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... THE LOW WILL BE MOVING ACROSS THE REGION WED MORNING INTO EARLY AFTERNOON...THEN RE-CONSOLIDATING TO THE NORTH IN THE AFTERNOON. HEAVY RAIN...STRONG SOUTHERLY WINDS AND ISOLD RUMBLES OF THUNDER WILL STILL BE ONGOING INITIALLY...THEN SHOULD SHIFT TO THE EAST ACROSS ERN LONG ISLAND/CT DURING LATE MORNING AND LIFT UP INTO NEW ENGLAND BY AFTERNOON AS THIS TAKES PLACE. ENDED WIND ADVISORY EARLIER THAN ORIGINALLY FCST SINCE THE LOW TRACK SHOULD BE SLIGHTLY FARTHER EAST...WITH THE LOW LEVEL JET ALSO PASSING TO THE EAST SOONER. RAIN SHOULD LESSEN IN INTENSITY AS WELL AS AS THE LOW LEVEL JET PASSES TO THE EAST. AS THE LOW MOVES OVER THE AREA...THERE SHOULD BE A RELATIVE LULL IN WINDS FROM LATE MORNING INTO EARLY AFTERNOON...THEN STRONG NW WINDS WILL REDEVELOP BY EVENING AS THE LOW CONTINUES TO INTENSIFY AND SHOULD CONTINUE INTO THE NIGHT...SUSTAINED AT 20-30 MPH WITH GUSTS UP TO 40 MPH...POSSIBLY STRONGER IN NYC METRO AND LONG ISLAND WHERE ANOTHER WIND ADVISORY MAY BE NEEDED. STILL EXPECT SCT SHOWERS IN THE EVENING AS THE UPPER TROUGH MOVES ACROSS...AND LOW LEVEL CAA SHOULD CHANGE ANY PRECIP OVER TO SNOW FROM NYC NORTH/WEST. SOME INTERIOR AREAS COULD SEE A LIGHT COATING OF ACCUMULATION OF SNOW BEFORE ALL PRECIP ENDS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... VIGOROUS SHORTWAVE IS ROTATING EAST OF THE REGION EARLY THURSDAY MORNING AS BROAD UPPER TROUGH REMAINS ACROSS THE NORTHEAST. ANOTHER SHORTWAVE ROTATES THROUGH THE TROUGH LATE THURSDAY INTO THURSDAY NIGHT. MEANWHILE AT THE SURFACE LOW PRESSURE WILL BE NORTH AND EAST OF THE AREA AND CONTINUING TO MOVE NORTH DURING THE DAY INTO THURSDAY NIGHT AS HIGH PRESSURE BUILDS TO THE WEST. INCREASING SUBSIDENCE BEHIND THE LOW WILL KEEP AREA PRECIPITATION FREE THURSDAY...ALTHOUGH CLOUDS WILL LINGER EARLY IN THE DAY. UPPER FLOW BECOMES MORE ZONAL FRIDAY AND INTO THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS OVER THE REGION. WARM ADVECTION SETS UP LATE SATURDAY NIGHT AND INTO SUNDAY AS HIGH PRESSURE MOVES EAST AND NEXT SHORTWAVE APPROACHES FROM THE GREAT LAKES. LIFT IS RATHER WEAK AT THIS TIME AND MOISTURE LIMITED HOWEVER...THERE IS A VERY LOW PROBABILITY OF LIGHT PRECIPITATION LATE SATURDAY NIGHT. SUNDAY WILL BE A BETTER CHANCE AS ADVECTION CONTINUES AND GULF MOISTURE MOVES INTO THE AREA. AS THE HIGH RETREATS TO THE NORTHEAST SATURDAY NIGHT INTO SUNDAY...COLD AIR DAMNING IS POSSIBLE AND MIXED PRECIPITATION WILL BE POSSIBLE INLAND AS COASTAL AREAS WARM IN THE SOUTHERLY FLOW. A COASTAL FRONT DEVELOPS SUNDAY INTO MONDAY AS A WEAK SOUTHERN STREAM SHORTWAVE MOVES OUT OF THE SOUTHWEST AND INTO THE GULF COAST REGION. THIS WAVE WILL DEVELOP A LOW ALONG THE COASTAL FRONT MONDAY INTO TUESDAY. STILL SOME UNCERTAINTY WITH THE TRACK OF LOW WITH THE ECMWF CLOSER TO THE COAST AND THE GFS MOVING THE LOW FARTHER OFF THE SOUTHEASTERN COAST AND KEEPING THE REGION ON THE NORTHWESTERN EDGE OF THE PRECIPITATION TUESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... **HIGH IMPACT AVIATION WEATHER EVENT FOR TONIGHT AND WEDNESDAY** DETERIORATING CONDITIONS REST OF TONIGHT WITH AN APPROACHING LOW PRESSURE SYSTEM. VARYING IFR/LIFR CONDITIONS THROUGH THE MORNING...WITH GRADUAL IMPROVEMENT THIS AFTERNOON INTO TONIGHT. WINDS INCREASING...WITH OCNL GUSTS THROUGH 07Z...AND MORE PERSISTENT THEREAFTER QUICKLY INCREASING TO BETWEEN 20 AND 30 KT. WIND SHEAR BECOMES AN ISSUE NYC TERMINALS AND EAST 08Z-14Z TODAY...WITH SLY WINDS UP TO 70 KT AT 2000 FT. WINDS GRADUALLY DIMINISH AND SHIFT TO THE SW THEN NW BY THIS AFTERNOON. TIMING OF WIND SHIFTS MAY BE 1-2 HOURS. GUSTS WILL REMAIN ACROSS THE ENTIRE AREA INTO TONIGHT...THOUGH A BRIEF LULL AS WINDS SHIFT FROM S TO NW IS POSSIBLE. EXPECT IFR AND LIFR CIGS AS HEAVIER PRECIPITATION MOVES IN THE REST OF THE NIGHT. BEST CHANCE FOR LIFR WILL BE BETWEEN 07Z AND 15Z. PRECIPITATION LINGERS DURING THE DAY...WITH GRADUALLY IMPROVING CIGS AFTER 15Z. PRECIPITATION SHOULD REMAIN ALL RAIN FROM HERE ON OUT. .OUTLOOK FOR 06Z THURSDAY THROUGH MONDAY... .WED NIGHT. VFR. W-NW WINDS 20-25G35KT. .THU...VFR. NW WINDS 20-25G30-35KT EARLY SLOWLY DIMINISHING TO G20KT BY EVENING. .THU NIGHT-SAT...VFR. .SUN AND MON...MVFR CEILINGS. -DZ / -RA. SE SFC FLOW 10-15 KT. && .MARINE... MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN TONIGHT AHEAD OF AN ADVANCING STORM SYSTEM TRACKING FROM THE SOUTHEASTERN TO COASTAL MID ATLANTIC STATES TONIGHT...WITH WIND GUSTS TO GALE LEVELS DEVELOPING AFTER MIDNIGHT. A FEW GUSTS TO STORM FORCE MAY BE POSSIBLE TOWARD MORNING...MAINLY ON THE ERN OCEAN WATERS...BUT THESE SHOULD BE BRIEF AT BEST AND SO DID NOT UPGRADE ANY AREAS TO A STORM WARNING. WILL USE SPECIAL MARINE WARNINGS TO ADDRESS ANY WIND GUSTS OF 48 KT OR HIGHER IN ISOLATED STRONGER CONVECTION. SEAS COULD BUILD AS HIGH AS 16 FT ON THE ERN OCEAN WATERS WITH THE STRONGEST SOUTHERLY WINDS. THERE COULD BE A LULL IN WINDS FROM LATE WED MORNING INTO THE AFTERNOON...BUT THEN NW GALES ARE EXPECTED WED NIGHT INTO THU MORNING...WITH SEAS UP TO 15 FT EXPECTED WED NIGHT ON THE OCEAN AND AS HIGH AS 7 FT ON LONG ISLAND SOUND AS THE SURFACE LOW CONTINUES TO TRACK TO THE NORTH THROUGH CANADA AND HIGH PRESSURE BUILDS TO THE WEST. THE WIND WILL BE DIMINISHING THROUGH THE DAY THURSDAY...SUBSIDING BELOW GALE FORCE DURING THE AFTERNOON...AND THEN QUICKLY FALLING BELOW 25 KT DURING THURSDAY EVENING. VERY ROUGH SEAS ON THE OCEAN WATERS SUBSIDE DURING THURSDAY IN THE WEST TO NORTHWEST FLOW. BY LATE THURSDAY NIGHT SEAS ARE EXPECTED TO FALL BELOW 5 FT AS THE WESTERLY FLOW DIMINISHES. WIND AND SEAS REMAIN BELOW ADVISORY LEVELS FRIDAY INTO SUNDAY. DEPENDING ON THE STRENGTH OF THE WIND AROUND A DEPARTING HIGH AND A DEVELOPING TROUGH ALONG THE COAST...SEAS ON THE OCEAN WATERS MAY BUILD BACK UP TO SMALL CRAFT LEVELS LATE SUNDAY INTO SUNDAY NIGHT. && .HYDROLOGY... WIDESPREAD RAINFALL TOTALS FORECAST RANGE BETWEEN 2 AND 3 INCHES WITH LOCAL AMOUNTS UP TO 4 INCHES. DUE TO RECENT PROLONGED DRY CONDITIONS...MAIN STEM RIVER FLOODING IS NOT EXPECTED. HOWEVER...THERE IS ENOUGH CHANCE OF URBAN/AREAL/SMALL STREAM FLOODING...ESPECIALLY WHERE STORM DRAINS ARE CLOGGED BY LEAVES AND ESSENTIALLY WHERE THERE IS MORE RUNOFF. ADDITIONALLY...LOW-LYING COASTAL AREAS MAY EXPERIENCE EXACERBATED ROAD FLOODING DURING TIMES OF HIGH TIDE WEDNESDAY MORNING. LIGHT PRECIPITATION IS POSSIBLE SUNDAY INTO TUESDAY...WITH A TOTAL OF UP TO A HALF INCH EXPECTED AT THIS TIME. && .TIDES/COASTAL FLOODING... A GALE FORCE SE FLOW WILL RAPIDLY DEVELOP AHEAD OF DEEPENING LOW PRESSURE LATE TONIGHT...BEFORE VEERING TO THE S WEDNESDAY MORNING. A STORM SURGE OF 2 TO 2 1/2 FT...LOCALLY 3 FT IS EXPECTED. THE PEAK SURGE COINCIDES BEST WITH THE TIMING OF THE MORNING HIGH TIDE CYCLE IN WESTERN LONG ISLAND SOUND AND PECONIC BAY. AN ADVISORY HAS BEEN ISSUED IN THESE LOCATIONS WITH COMBINED THREAT OF STORM TIDE...WAVE SPLASH-OVER...AND HEAVY RAIN CAUSING WIDESPREAD MINOR IMPACTS. ELSEWHERE...TIMING OF PEAK SURGE AND HIGH TIDE APPEARS TO BE OFFSET...WITH ONLY LOCALIZED ISSUES EXPECTED WITH WEDNESDAY MORNING HIGH TIDE DUE TO STORM TIDE AND HEAVY RAIN. A COASTAL FLOOD STATEMENT HAS BEEN ISSUED TO ADDRESS THIS THREAT. FOR THE LATE AFTERNOON/EVENING HIGH TIDE CYCLE...WITH FLOW EXPECTED TO BEGIN TURN OFFSHORE WOULD EXPECT SURGE VALUES TO BEGIN TO FALL RAPIDLY FROM AFTERNOON ON. THE ONLY AREA TO MONITOR WOULD BE THE SOUTH SHORE BACK BAYS WITH HIGH SURF LIMITING TIDAL DRAINAGE. HIGH SURF AND MINOR EROSION ISSUES ARE EXPECTED LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT FROM BATTERING SURF OF 7-11 FT. MAIN CONCERN WILL BE THE VULNERABLE DUNES AND BREACH LOCATIONS POST SANDY. A HIGH SURF ADVISORY HAS BEEN ISSUED TO ADDRESS THIS THREAT. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THIS AFTERNOON FOR CTZ005>012. WIND ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR CTZ008-011-012. WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR CTZ007-009-010. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST THIS MORNING FOR CTZ009-010. NY...FLOOD WATCH THROUGH THIS AFTERNOON FOR NYZ067>075-078>081- 176>179. WIND ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR NYZ078>081-177- 179. COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR NYZ079- 081. WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR NYZ071>075-176- 178. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST THIS MORNING FOR NYZ071-073. HIGH SURF ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ080-081- 178-179. NJ...FLOOD WATCH THROUGH THIS AFTERNOON FOR NJZ002-004-006-103>108. WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR NJZ006. MARINE...GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ330-335-338-340- 345-350-353-355. && $$ SYNOPSIS...GOODMAN/MET NEAR TERM...GOODMAN/MALOIT/NV SHORT TERM...GOODMAN LONG TERM...MET AVIATION...SEARS MARINE...GOODMAN/MALOIT/MET HYDROLOGY...GOODMAN/MET TIDES/COASTAL FLOODING... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS JACKSON KY
137 AM EST WED NOV 27 2013 .UPDATE... ISSUED AT 1035 PM EST TUE NOV 26 2013 IT LOOKS LIKE THE BULK OF THIS FIRST ROUND OF SNOW WILL WIND DOWN AFTER 06Z BEFORE UPSLOPE KICKS IN AND RENEWS THE MOISTURE AND SNOW SHOWERS WEDNESDAY MORNING. THE MODELS CONTINUE TO PLAY CATCH-UP WITH REALITY AS THE LATEST NAM12 AT 00Z IS STILL INSISTING ON A DECENT 1 TO 2 INCH BAND OF SNOW OVER MUCH OF THE AREA BETWEEN NOW AND MIDNIGHT. OTHER THAN THAT...THE REST OF THE EVENT WILL LIKELY BE MORE ELEVATIONALLY AND UPSLOPE DRIVEN. ACCORDINGLY HAVE LOWERED AMOUNTS FOR ALL BUT THE HIGHER ELEVATIONS IN THE EAST WITH THIS UPDATE. WILL HOLD ON TO THE CURRENT ARRANGEMENT OF ADVISORIES AND WARNINGS... THOUGH. REPORTS OF A PILE UP ON INTERSTATE 75 IN WHITLEY COUNTY POINTS OUT THAT IT DOESN/T TAKE MUCH SNOW OR SLEET TO BE VERY DANGEROUS. HOWEVER...WILL UPDATE THE WSW AND ZONES TO REFLECT A GREATER SPREAD IN THE AMOUNTS BASED ON TERRAIN...LIMITING THE VALLEY AMOUNTS. LOOK FOR THESE UPDATES OVER THE NEXT 15 MINUTES OR SO. UPDATED GRIDS AND SNOW TOTAL GRAPHICS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 650 PM EST TUE NOV 26 2013 23Z SFC ANALYSIS SHOWS A DEEPENING LOW PRESSURE CENTER OVER SOUTHEAST GEORGIA. THIS SYSTEM IS NOW WRAPPING THE COLD AIR INTO EAST KENTUCKY AND AS A RESULT THE WESTERN PARTS OF ITS COMMA HEAD OF PCPN IS TRANSITIONING TO SNOW...HEAVY AT TIMES. ON WV SATELLITE...THE SOUTHERN SHORT WAVE SHOWS UP WELL AS IT PUNCHES INTO THE REGION. THIS WILL QUICKLY RENEW THE PCPN RETURNS THROUGH THIS PART OF KENTUCKY AND THE EASTERN TENNESSEE VALLEY AS THE FIRST WAVE MOVES OUT. PER THE LATEST HRRR AND 18Z NAM12 HAVE INCORPORATED THIS INTO THE FORECAST AND FINE TUNED SNOW AMOUNTS AND TIMING OF THIS WINTER EVENT THROUGH THE NIGHT...GENERALLY A BIT MORE SNOW TO THE NORTHEAST AND A ONE TO TWO HOUR FASTER CHANGEOVER HEADING EAST. THE LATEST TWEETS AND OBS INDICATE THAT THE SNOW LINE IS MOVING DEEPER INTO OUR NORTHWESTERN COUNTIES WITH ENHANCEMENTS ON RADAR SUGGESTING A QUICK INCH POSSIBLE AS THIS BAND MOVES EAST. THE UPDATED FORECAST HAS BEEN SENT TO THE NDFD AND WEB SERVERS. A ZFP UPDATE WILL FOLLOW SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 256 PM EST TUE NOV 26 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE PROGRESSION OF THE SYSTEM. SOME HEAVY RAIN HAS PROMPTED AN AREAL FLOOD ADVISORY FOR WHITLEY KNOX AND BELL COUNTIES. THE RAIN SHOULD BEGIN TO TAPER OFF A LITTLE IN THE NEXT FEW HOURS. PUT A SLIDE ON THE INTERNET TO SHOW THE PROGRESSION OF THE CHANGEOVER THIS EVENING FROM RAIN TO SNOW. FOR THE SNOW AMOUNTS...THE NEW MODEL RUNS HAD LITTLE CHANGE. THE DIFFERENCES IN THE NEW SNOW AMOUNT FORECAST WERE NOT VERY SIGNIFICANT. FEEL LIKE THE FORECAST HAS CAPTURED THE UPPER END OF THE SNOW FORECAST. ONE CONCERN IS THE COMBINATION OF THE SNOW AND THE WIND FOR TOMORROW AND TOMORROW EVENING. THIS HAS THE POTENTIAL FOR CREATING NEAR BLIZZARD CONDITIONS WITH LOW VISIBILITY DUE TO THE BLOWING SNOW. IT WILL ALSO CAUSE THE WIND CHILLS TO DIP DOWN PRETTY LOW. ANYONE TRAVELING ON WEDNESDAY NEED TO HAVE BLANKETS AND WARM COATS IN THE CAR. WITH THE NORTHERLY WINDS BEHIND THE SYSTEM... UPSLOPE WILL BE A FACTOR AT UPPER ELEVATIONS ALONG THE VIRGINIA AND TENNESSEE BORDERS. THE UPPER ELEVATIONS ABOVE 2000 FEET HAVE A POTENTIAL TO SEE SOME PRETTY SUBSTANTIAL SNOW AMOUNTS. WILL UPDATE THE CHANGE OVER FORECAST SLIDE ON THE INTERNET WITH THE FORECAST CHANGEOVER TIMES IF THE FORECAST CHANGES. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 256 PM EST TUE NOV 26 2013 UPPER LEVEL TROUGH WILL LINGER THROUGH THANKSGIVING DAY WITH A TREND TOWARDS ZONAL FLOW AS WE HEAD INTO THE WEEKEND. THIS WILL YIELD A COLD THANKSGIVING DAY...WITH A SLOW WARMING TREND INTO THE WEEKEND. HIGH PRESSURE WILL SKIRT ACROSS THE AREA FROM THURSDAY THROUGH SATURDAY...PROVIDING A QUIET STRETCH OF WEATHER FOR A GOOD CHUNK OF THE HOLIDAY WEEKEND. A FAST MOVING SHORTWAVE WILL PUSH EAST ACROSS THE AREA LATE IN THE WEEKEND...PRODUCING A SMALL CHANCE FOR RAIN. A STRONGER SOUTHERN STREAM WAVE WILL PUSH SOUTH OF THE AREA MONDAY INTO MONDAY NIGHT...PRODUCING A BETTER CHANCE FOR SOME RAIN. OVERALL...MODELS ARE IN PRETTY DECENT AGREEMENT...SO CONFIDENCE IS DECENT WELL INTO THE EXTENDED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 137 AM EST WED NOV 27 2013 INITIAL CONDITIONS WERE A MIX OF IFR AND LOW END MVFR OVER MOST OF THE AREA. LIGHT SNOW WAS ALSO FALLING IN MOST PLACES. THE LIGHT SNOW WILL EASE UP FROM WEST TO EAST OVERNIGHT AND EARLY WEDNESDAY...BUT MIXED IFR AND MVFR CEILINGS WILL LINGER UNTIL PAST SUNRISE BEFORE IMPROVEMENT TO MOSTLY MVFR TAKES PLACE DURING THE MORNING. REDEVELOPMENT OF SNOW SHOWERS IS FORECAST AROUND MIDDAY. THEY MAY BRING LOCALIZED SHARP REDUCTIONS IN VISIBILITY DURING THE AFTERNOON. THE SNOW SHOWERS WILL TAPER OFF FROM WEST TO EAST LATE IN THE AFTERNOON AND EARLY IN THE EVENING...WITH CEILINGS BREAKING UP AT THE SAME TIME...LEAVING VFR TO FINISH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR KYZ044- 050>052-058>060-069-080-085-086-104-106>109-111-112-114-116. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR KYZ068- 079-083-084. WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR KYZ087-088- 110-113-115-117>120. && $$ UPDATE...GREIF SHORT TERM...JJ LONG TERM...KAS AVIATION...HAL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1152 PM EST TUE NOV 26 2013 .UPDATE... ISSUED AT 1034 PM EST TUE NOV 26 2013 MAIN FCST CONCERNS OVERNIGHT ARE HEADLINES AND LES TRENDS. WITH KDLH RADAR SHOWING LES BANDS STREAMING INTO FAR WRN UPPER MI TOWARD THE KIWD AREA...SNOW LIKELY HAS HAS BEEN FAIRLY HVY IN THAT AREA THIS EVENING. BANDS HAVE BEEN MOVING THOUGH...PREVENTING MORE SUBSTANTIAL ACCUMULATION. OVER ERN LAKE SUPERIOR...LES HAS BECOME MORE WIDESPREAD WITH A GENERAL UPTICK IN INTENSITY UNDER STRONGER LOW-LEVEL CONVERGENCE ALONG SOUTHWARD MOVING SFC TROF. HOWEVER... WITH SHORTWAVE TROF NOW SLIPPING E OF LAKE SUPERIOR PER WATER VAPOR IMAGERY...HAVE CONCERN THAT SNOW ACCUMULATIONS NEED TO BE TONED DOWN ACROSS THE BOARD OVERNIGHT/WED MORNING AS MODEL GUIDANCE SHOWS RATHER HEALTHY LARGE SCALE QVECTOR DIVERGENCE DOMINATING THRU WED MORNING BEHIND WAVE. SO...APART FROM LOCALIZED LOW-LEVEL CONVERGENCE/UPSLOPE TERRAIN ENHANCEMENT...LES MAY MOSTLY BE ON THE LIGHTER SIDE. ON THE PLUS SIDES...DGZ SHOULD BE FAIRLY WELL CENTERED WITHIN THE UPWARD MOTION ZONE TO FLUFF UP SNOW ACCUMULATIONS...AND UPSTREAM 00Z CWPL SOUNDING SHOWED A DEEP MOISTURE PROFILE THRU ABOUT 11KFT OR SO. HOWEVER...GIVEN THE LARGE SCALE NEGATIVES...GENERALLY LOWERED SNOW ACCUMULATIONS FROM THIS POINT FORWARD. THE WARNING FOR MARQUETTE COUNTY MAY BE TOUGH TO ACHIEVE. IF ANY PLACE DOES REACH WARNING CRITERIA...IT WILL PROBABLY BE THE HIGHER TERRAIN N AND NW OF NEGAUNEE WHERE UPSLOPE IS MAXIMIZED. ADVY IS PRETTY MARGINAL FOR THE KEWEENAW OVERNIGHT WITH WINDS BECOMING A LESS FAVORABLE NORTHERLY DIRECTION. STILL MAY SEE A FEW HEAVIER SNOW BANDS TRAVERSE THE KEWEENAW...AND GUSTY WINDS...MAINLY ALONG THE LAKE...WILL LEAD TO BLSN. OVER THE FAR W...PRECONDITIONING FROM LAKE NIPIGON MAY STILL FAVOR MORE PERSISTENT HEAVIER SNOW...MAINLY FROM THE PORCUPINE MTNS TO KIWD VCNTY AS THE NIGHT WEARS ON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 505 PM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON. AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED 8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES. EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7 INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4 OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES WARNING FOR TONIGHT THROUGH WEDNESDAY. FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA. INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER OFF WED AFTERNOON FROM WEST TO EAST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 416 PM EST TUE NOV 26 2013 UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST LOCATIONS. THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT THINKING REMAINS. OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER 20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE DISTURBANCE. EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE 30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1152 PM EST TUE NOV 26 2013 LAKE EFFECT SNOW SHOWERS WILL CONTINUE AT KIWD/KCMX/KSAW THRU MUCH IF NOT ALL OF THIS FCST PERIOD. AS IS TYPICAL FOR LAKE EFFECT... CONDITIONS WILL VARY CONSIDERABLY FROM VFR TO AS LOW AS IFR OR EVEN BRIEF LIFR. LOWEST CONDITIONS WILL BE MORE COMMON AT KIWD/KSAW DUE TO UPSLOPING NORTHERLY WIND. CONDITIONS WILL GENERALLY VARY BTWN MVFR AND IFR THRU THE MORNING...WITH LIFR POSSIBLE AT TIMES... ESPECIALLY AT KSAW EARLY ON IN THE FCST PERIOD. AT KCMX...NORTHERLY WINDS ARE GENERALLY NOT AS FAVORABLE FOR MORE PERSISTENT LOW CONDITIONS. CONDITIONS SHOULD GENERALLY BE MVFR WITH BRIEF PERIODS OF IFR OVERNIGHT...BUT PERIODS OF VFR ARE ALSO LIKELY. ARRIVAL OF DRIER AIR AND MORE ANTICYCLONIC FLOW LATE MORNING THRU THE AFTN WILL RESULT IN PREVAILING MVFR AT ALL TERMINALS BY AFTN. SOME PERIODS OF VFR ARE ALSO POSSIBLE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST TUE NOV 26 2013 WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE 2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR. LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER MAINLY E LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004- 006. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005. LAKE SUPERIOR... GALE WARNING UNTIL 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING UNTIL 10 AM EST WEDNESDAY FOR LSZ265. GALE WARNING UNTIL 5 AM EST WEDNESDAY FOR LSZ264. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...VOSS LONG TERM...KF AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
305 AM EST WED NOV 27 2013 .SYNOPSIS... A STORM SYSTEM WILL MOVE THROUGH THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH A VARIETY OF MIXED...WINTRY PRECIPITATION. THIS SYSTEM WILL LIKELY CAUSE DIFFICULT TO LOCALLY HAZARDOUS TRAVEL ACROSS THE REGION. BEHIND THIS SYSTEM A RETURN TO COLD AND MAINLY DRY CONDITIONS ARE EXPECTED BY FRIDAY AND INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... AS OF 1153 PM EST TUESDAY...GOING FORECAST IN REAL GOOD SHAPE AND SEE NO REASON TO CHANGE ANYTHING AT THIS TIME. WARNINGS AND ADVISORIES REMAIN IN PLACE. .PREVIOUS FORECAST... FORECAST REMAINS MORE OR LESS ON TRACK. SNOW CONTINUES ACROSS MUCH OF THE REGION WITH ACCUMULATIONS SO FAR IN THE TRACE-2" RANGE. RAP 850/925 MB 0C LINES STILL DOING QUITE WELL DEPICTING THE CHANGEOVER FROM SNOW TO ICE/RAIN. AS OF 10PM...IT HAS PROGRESSED TO NEAR WHITE RIVER JUNCTION VERMONT WESTWARD TO GLENS FALLS AND STILL MOVING NORTHWARD. CHANGEOVER ACROSS THE REST OF THE AREA EXCEPT THE SAINT LAWRENCE VALLEY BETWEEN NOW AND 07Z FROM SOUTH TO NORTH. EXPECTING THE SAINT LAWRENCE VALLEY TO REMAIN PRIMARILY SNOW. 1 TO 3" FOR MUCH OF CHAMPLAIN VALLEY AND VERMONT BEFORE CHANGEOVER STILL LOOKS GOOD...WITH 2 TO 5" IN THE ADIRONDACKS...AND 4 TO 8" IN THE SAINT LAWRENCE VALLEY BY MORNING. ICE ACCRUAL OF UP TO A QUARTER OF AN INCH ALSO STILL LOOKS GOOD FOR PORTIONS OF THE ADIRONDACKS AND EASTERN VERMONT. OTHER CONCERN WILL BE SOME GUSTY SOUTHEAST DOWNSLOPE WINDS IN THE SOUTHERN GREENS...WHERE GUSTS UP TO 40 MPH ARE POSSIBLE OVERNIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH FRIDAY/... AS OF 315 PM EST TUESDAY...MODESTLY DEEP SFC LOW THEN TRACKS ATOP OR JUST EAST OF THE FORECAST AREA DURING WEDNESDAY. THUS EXPECTING MAINLY A WIDESPREAD RAIN EVENT ACROSS VT AND CONTINUED ACCUMULATING WINTRY PCPN FROM THE DACKS INTO THE SLV AS MEAN 925/850 MB 0C LINE BACKS WESTWARD. COPIOUS MOISTURE FEED...ESP ALONG AND EAST OF THE LOW TRACK SEEMS A GOOD BET WITH MEAN MODEL PWAT ANOMALIES RANGING FROM 200-300% OF NORMAL OCCURRING ACROSS THE ERN HALF OF VERMONT DURING THE DAYLIGHT HOURS. THIS WILL CREATE SOME MODEST HYDROLOGICAL CONCERNS IN THESE AREAS WITH ADDITIONAL SUPPORT COMING FROM TIGHT BAROCLINICITY AND DEEP FRONTOGENETICAL FORCING (SEE HYDRO SECTION BELOW). TEMPERATURES ALL OVER THE PLACE...WITH NRN NY COUNTIES HOLDING MAINLY IN THE LOWER TO MID 30S WHILE AREAS ACROSS FAR EASTERN VERMONT SHOULD EASILY MAKE IT INTO THE LOWER AND MID 40S WITH A SPOT 50 NOT OUT OF THE QUESTION FROM WHITE RIVER JCT SOUTH. AS THE LOW SWINGS BY WEDNESDAY EVENING/NIGHT...THE LOWER TO MID LEVEL 0C LINE WILL BEGIN TO ADVANCE RAPIDLY EASTWARD SUCH THAT PCPN WILL RATHER QUICKLY TRANSITION BACK TO SNOW FROM EAST TO WEST DURING THE 00-06Z TIME FRAME. THUS ADDITIONAL SNOW ACCUMULATIONS EXPECTED IN ALL AREAS...ESP NORTHERN MTNS WHERE TYPICAL OROGRAPHICAL EFFECTS WILL ENHANCE LOCAL RATES. TEMPERATURES CRASHING SHARPLY DURING THE PERIOD AS WELL SO SOME QUICK FREEZE-UP OF AREA ROADS CERTAINLY POSSIBLE...SIMILAR TO A FEW NIGHTS BACK. READINGS BY MORNING GENERALLY FROM 10 TO 20 WITH A GUSTY WNW WIND. BY THURSDAY LINGERING NRN MTN SHSN SLOWLY WANE THROUGH THE DAY AS HIGH PRESSURE NOSES EASTWARD AND SUNSHINE BECOMES MORE AND MORE PREVALENT. QUITE A COLD/BLUSTERY DAY HOWEVER AS TEMPERATURES HOLD MORE OR LESS STEADY FROM 15 TO 25 UNDER STRONG COLD THERMAL ADVECTION AND CONTINUED GUSTY WNW FLOW. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 304 AM EST WEDNESDAY...MAINLY WENT WITH THE SUPERBLEND FOR THE EXTENDED PORTION OF THE FORECAST THIS MORNING SO THAT MORE FOCUS COULD BE ON THE NEAR/SHORT TERM PORTIONS OF THE FORECAST. FRIDAY NIGHT AND SATURDAY WILL BE DRY WITH RIDGE OF SURFACE HIGH PRESSURE OVER THE AREA AND THEN SLOWLY SLIDING EAST. FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT A WEAK LOW PRESSURE SYSTEM WILL PASS EITHER JUST NORTH OF OUR AREA OR ACROSS OUR FORECAST AREA BRINGING SNOW SHOWERS TO THE NORTH COUNTRY. MONDAY AND MONDAY NIGHT WILL GENERALLY BE DRY. A LOW PRESSURE SYSTEM TRACKS ALONG THE EAST COAST IN THE TUESDAY THROUGH WEDNESDAY TIMEFRAME. GFS AND ECMWF STILL QUITE DIFFERENT WITH TRACK AND TIMING OF THIS STORM...BUT STILL FAR OUT TO DETERMINE THOSE DETAILS. AT THIS TIME LOOKS LIKE SOME PRECIP WILL AFFECT OUR FORECAST AREA TUESDAY AND TUESDAY NIGHT...THEN WINDING DOWN EARLY WEDNESDAY. RIGHT NOW IT LOOKS LIKE RAIN...BUT AGAIN...LOTS OF UNCERTAINTY AT THIS POINT AND AS WE GET CLOSER TO NEXT WEEK THE DETAILS WILL BECOME MORE CLEAR AND OF COURSE THE MODELS SHOULD COME MORE INTO LINE. TEMPERATURES WILL INITIALLY BE BELOW NORMAL BUT THEN TREND BACK TOWARDS NORMAL LATER IN THE PERIOD. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...WIDESPREAD IFR WITH AREAS OF MVFR EXPECTED THROUGH THE PERIOD. SNOW HAS BEGUN TO TRANSITION TO RAIN OVER THE LAST HOUR OR TWO AT ALL SITES EXCEPT KMSS AND KSLK. ALMOST ALL TERMINALS IN VT REPORTING RAIN AT THIS TIME...AS WELL AS PBG. MIX CONTINUES AT KSLK WITH SNOW AT KMSS...WHICH MAY BE HEAVY AT TIMES. PRECIPITATION THEN TRANSITIONS BACK TO SNOW FROM WEST TO EAST ACROSS THE AREA WEDNESDAY AFTERNOON. STRONG LOW LVL JET WILL APPROACH EASTERN VT...CREATING LLWS OF 40-50KTS FOR KRUT AND KMPV BETWEEN 08Z-14Z. AT THE SFC...WINDS WILL BE LESS THAN 10 KTS TONIGHT AT ALL SITES EXCEPT KRUT WHICH WILL SEE SOUTHEAST WINDS GUSTING 20-25 KTS. WINDS BECOMING NORTHERLY 8-15 KTS ACROSS THE REGION ON WEDNESDAY AS SFC LOW TRACKS FROM NEAR NYC WEDNESDAY MORNING INTO EASTERN NEW ENGLAND. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... 06Z THURSDAY THROUGH 18Z THURSDAY...MVFR AND IFR CATEGORIES CONTINUE INTO THANKSGIVING MORNING. SNOW WEDNESDAY EVENING TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY THROUGH 12Z SUNDAY...MAINLY VFR AS HIGH PRESSURE MOVES ACROSS REGION. 12Z SUNDAY ONWARD...VFR/MVFR IN SCATTERED SNOW SHOWERS. && .HYDROLOGY... AS OF 315 PM EST TUESDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS CONTINUE TO SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE A SOLID 1.5 TO 2.5 QPF EVENT IS LIKELY. PROBLEMATIC WILL BE AT LEAST SOME FRONT END FROZEN PCPN TONIGHT AND TYPICAL SHADOWING EFFECTS DEPENDING ON LOCALE DURING WEDNESDAY. HOWEVER SSHP OUTPUT USING FORECAST QPF FROM 06Z-00Z WED AND INCORPORATING A MODEST 0.15 TO 0.25 SWE MELT SHOW SEVERAL EASTERN/SOUTHERN VT WATERSHEDS NEARING BANKFULL LATER WED/WED NIGHT. THIS IS IN CLOSE AGREEMENT WITH COORDINATED NERFC/AHPS FORECASTS AND GIVEN ANOMALOUS 12-HR PWAT SURGE NOTED ABOVE...HAVE OPTED TO ISSUE A FLOOD WATCH FOR MUCH OF THIS AREA ACCORDINGLY. THIS IS NOT A HIGH END EVENT...BUT SOME MINOR/NUISANCE FLOODING ALONG BOTH HEADWATER AND MAINSTEM RIVERS WILL BE POSSIBLE LATER WED/WED NT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR VTZ001>012-016>019. FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH LATE TONIGHT FOR VTZ004-007-008-010>012-018-019. NY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NYZ026-027- 029>031-034-087. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NYZ028- 035. && $$ SYNOPSIS...JMG NEAR TERM...EVENSON/MUCCILLI SHORT TERM...JMG LONG TERM...NEILES AVIATION...NEILES HYDROLOGY...JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1238 AM EST WED NOV 27 2013 .SYNOPSIS... A STORM SYSTEM WILL MOVE THROUGH THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH A VARIETY OF MIXED...WINTRY PRECIPITATION. THIS SYSTEM WILL LIKELY CAUSE DIFFICULT TO LOCALLY HAZARDOUS TRAVEL ACROSS THE REGION. BEHIND THIS SYSTEM A RETURN TO COLD AND MAINLY DRY CONDITIONS ARE EXPECTED BY FRIDAY AND INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... AS OF 1153 PM EST TUESDAY...GOING FORECAST IN REAL GOOD SHAPE AND SEE NO REASON TO CHANGE ANYTHING AT THIS TIME. WARNINGS AND ADVISORIES REMAIN IN PLACE. .PREVIOUS FORECAST... FORECAST REMAINS MORE OR LESS ON TRACK. SNOW CONTINUES ACROSS MUCH OF THE REGION WITH ACCUMULATIONS SO FAR IN THE TRACE-2" RANGE. RAP 850/925 MB 0C LINES STILL DOING QUITE WELL DEPICTING THE CHANGEOVER FROM SNOW TO ICE/RAIN. AS OF 10PM...IT HAS PROGRESSED TO NEAR WHITE RIVER JUNCTION VERMONT WESTWARD TO GLENS FALLS AND STILL MOVING NORTHWARD. CHANGEOVER ACROSS THE REST OF THE AREA EXCEPT THE SAINT LAWRENCE VALLEY BETWEEN NOW AND 07Z FROM SOUTH TO NORTH. EXPECTING THE SAINT LAWRENCE VALLEY TO REMAIN PRIMARILY SNOW. 1 TO 3" FOR MUCH OF CHAMPLAIN VALLEY AND VERMONT BEFORE CHANGEOVER STILL LOOKS GOOD...WITH 2 TO 5" IN THE ADIRONDACKS...AND 4 TO 8" IN THE SAINT LAWRENCE VALLEY BY MORNING. ICE ACCRUAL OF UP TO A QUARTER OF AN INCH ALSO STILL LOOKS GOOD FOR PORTIONS OF THE ADIRONDACKS AND EASTERN VERMONT. OTHER CONCERN WILL BE SOME GUSTY SOUTHEAST DOWNSLOPE WINDS IN THE SOUTHERN GREENS...WHERE GUSTS UP TO 40 MPH ARE POSSIBLE OVERNIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 315 PM EST TUESDAY...MODESTLY DEEP SFC LOW THEN TRACKS ATOP OR JUST EAST OF THE FORECAST AREA DURING WEDNESDAY. THUS EXPECTING MAINLY A WIDESPREAD RAIN EVENT ACROSS VT AND CONTINUED ACCUMULATING WINTRY PCPN FROM THE DACKS INTO THE SLV AS MEAN 925/850 MB 0C LINE BACKS WESTWARD. COPIOUS MOISTURE FEED...ESP ALONG AND EAST OF THE LOW TRACK SEEMS A GOOD BET WITH MEAN MODEL PWAT ANOMALIES RANGING FROM 200-300% OF NORMAL OCCURRING ACROSS THE ERN HALF OF VERMONT DURING THE DAYLIGHT HOURS. THIS WILL CREATE SOME MODEST HYDROLOGICAL CONCERNS IN THESE AREAS WITH ADDITIONAL SUPPORT COMING FROM TIGHT BAROCLINICITY AND DEEP FRONTOGENETICAL FORCING (SEE HYDRO SECTION BELOW). TEMPERATURES ALL OVER THE PLACE...WITH NRN NY COUNTIES HOLDING MAINLY IN THE LOWER TO MID 30S WHILE AREAS ACROSS FAR EASTERN VERMONT SHOULD EASILY MAKE IT INTO THE LOWER AND MID 40S WITH A SPOT 50 NOT OUT OF THE QUESTION FROM WHITE RIVER JCT SOUTH. AS THE LOW SWINGS BY WEDNESDAY EVENING/NIGHT...THE LOWER TO MID LEVEL 0C LINE WILL BEGIN TO ADVANCE RAPIDLY EASTWARD SUCH THAT PCPN WILL RATHER QUICKLY TRANSITION BACK TO SNOW FROM EAST TO WEST DURING THE 00-06Z TIME FRAME. THUS ADDITIONAL SNOW ACCUMULATIONS EXPECTED IN ALL AREAS...ESP NORTHERN MTNS WHERE TYPICAL OROGRAPHICAL EFFECTS WILL ENHANCE LOCAL RATES. TEMPERATURES CRASHING SHARPLY DURING THE PERIOD AS WELL SO SOME QUICK FREEZE-UP OF AREA ROADS CERTAINLY POSSIBLE...SIMILAR TO A FEW NIGHTS BACK. READINGS BY MORNING GENERALLY FROM 10 TO 20 WITH A GUSTY WNW WIND. BY THURSDAY LINGERING NRN MTN SHSN SLOWLY WANE THROUGH THE DAY AS HIGH PRESSURE NOSES EASTWARD AND SUNSHINE BECOMES MORE AND MORE PREVALENT. QUITE A COLD/BLUSTERY DAY HOWEVER AS TEMPERATURES HOLD MORE OR LESS STEADY FROM 15 TO 25 UNDER STRONG COLD THERMAL ADVECTION AND CONTINUED GUSTY WNW FLOW. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 246 PM EST TUESDAY...SFC HIGH PRESSURE WITH GRADUALLY CLEAR SKIES AS AN UPPER LVL TROUGH EXITS EAST ON FRIDAY. RIDGING AT THE SFC...AND SLGT RIDGING ALOFT WILL KEEP DRY AIR OVER THE REGION THROUGH EARLY SUNDAY. COLD TEMPERATURES FRIDAY AND FRIDAY NIGHT WILL BE MODERATED BY RETURN FLOW ON SATURDAY AS THE SFC HIGH SHIFTS EWD TOWARD NOVA SCOTIA. MAX TEMPS IN THE TEENS AND 20S ON FRIDAY WITH MIN TEMPS IN THE SINGLE DIGITS...AND NEGATIVE SINGLE DIGITS WILL WARM INTO THE TEENS SATURDAY NT AND 20S-M30S ON SUNDAY. UPPER LVL SHORTWAVE WILL BRING CLOUDS AND CHC FOR SNOW SUNDAY INTO EARLY MONDAY WITH THE POSSIBILITY OF A COASTAL STORM DEVELOPING MONDAY NT INTO TUESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...WIDESPREAD IFR WITH AREAS OF MVFR EXPECTED THROUGH THE PERIOD. SNOW HAS BEGUN TO TRANSITION TO RAIN OVER THE LAST HOUR OR TWO AT ALL SITES EXCEPT KMSS AND KSLK. ALMOST ALL TERMINALS IN VT REPORTING RAIN AT THIS TIME...AS WELL AS PBG. MIX CONTINUES AT KSLK WITH SNOW AT KMSS...WHICH MAY BE HEAVY AT TIMES. PRECIPITATION THEN TRANSITIONS BACK TO SNOW FROM WEST TO EAST ACROSS THE AREA WEDNESDAY AFTERNOON. STRONG LOW LVL JET WILL APPROACH EASTERN VT...CREATING LLWS OF 40-50KTS FOR KRUT AND KMPV BETWEEN 08Z-14Z. AT THE SFC...WINDS WILL BE LESS THAN 10 KTS TONIGHT AT ALL SITES EXCEPT KRUT WHICH WILL SEE SOUTHEAST WINDS GUSTING 20-25 KTS. WINDS BECOMING NORTHERLY 8-15 KTS ACROSS THE REGION ON WEDNESDAY AS SFC LOW TRACKS FROM NEAR NYC WEDNESDAY MORNING INTO EASTERN NEW ENGLAND. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... 06Z THURSDAY THROUGH 18Z THURSDAY...MVFR AND IFR CATEGORIES CONTINUE INTO THANKSGIVING MORNING. SNOW WEDNESDAY EVENING TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY THROUGH 12Z SUNDAY...MAINLY VFR AS HIGH PRESSURE MOVES ACROSS REGION. 12Z SUNDAY ONWARD...VFR/MVFR IN SCATTERED SNOW SHOWERS. && .HYDROLOGY... AS OF 315 PM EST TUESDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS CONTINUE TO SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE A SOLID 1.5 TO 2.5 QPF EVENT IS LIKELY. PROBLEMATIC WILL BE AT LEAST SOME FRONT END FROZEN PCPN TONIGHT AND TYPICAL SHADOWING EFFECTS DEPENDING ON LOCALE DURING WEDNESDAY. HOWEVER SSHP OUTPUT USING FORECAST QPF FROM 06Z-00Z WED AND INCORPORATING A MODEST 0.15 TO 0.25 SWE MELT SHOW SEVERAL EASTERN/SOUTHERN VT WATERSHEDS NEARING BANKFULL LATER WED/WED NIGHT. THIS IS IN CLOSE AGREEMENT WITH COORDINATED NERFC/AHPS FORECASTS AND GIVEN ANOMALOUS 12-HR PWAT SURGE NOTED ABOVE...HAVE OPTED TO ISSUE A FLOOD WATCH FOR MUCH OF THIS AREA ACCORDINGLY. THIS IS NOT A HIGH END EVENT...BUT SOME MINOR/NUISANCE FLOODING ALONG BOTH HEADWATER AND MAINSTEM RIVERS WILL BE POSSIBLE LATER WED/WED NT. && .MARINE... AS OF 1030 PM EST TUESDAY...A LAKE WIND ADVISORY IS NO LONGER IN EFFECT AS WINDS HAVE DROPPED BELOW ADVISORY CRITERIA. FOR THE REST OF TONIGHT WINDS WILL BE SOUTH AT 10 TO 20 KNOTS...BECOMING EAST TO NORTHEAST AT 5 TO 15 KNOTS TOWARDS MORNING. THE LULL IN THE WINDS WILL BE BRIEF HOWEVER. A COLD FRONT WILL PASS THROUGH THE REGION WEDNESDAY AFTERNOON AND WINDS WILL SHIFT TO THE NORTHWEST AND BECOME STRONG AGAIN AT 25-35 KNOTS WEDNESDAY EVENING...WITH WAVES BUILDING TO 4 TO 6 FEET WEDNESDAY NIGHT. ANOTHER ADVISORY WILL LIKELY BE NEEDED FOR WEDNESDAY NIGHT INTO THANKSGIVING DAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR VTZ001>012-016>019. FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH LATE TONIGHT FOR VTZ004-007-008-010>012-018-019. NY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NYZ026-027- 029>031-034-087. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NYZ028- 035. && $$ SYNOPSIS...JMG NEAR TERM...EVENSON/MUCCILLI SHORT TERM...JMG LONG TERM...KGM AVIATION...RJS/NEILES HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
350 AM CST WED NOV 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CST WED NOV 27 2013 CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHWESTERN SASKATCHEWAN/NORTH CENTRAL MONTANA. SOUTH WINDS AHEAD OF THE SYSTEM HAD DEVELOPED OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENING HOURS...AND STRONG WARM ADVECTION CONTINUED OVER THE WESTERN HALF OF NORTH DAKOTA AHEAD OF THIS SYSTEM. REGARDING TEMPERATURES...READINGS HAD RISEN INTO THE LOWER 20S ACROSS FAR WESTERN NORTH DAKOTA...AND INTO THE TEENS OVER WESTERN PORTIONS OF CENTRAL NORTH DAKOTA. THIS TREND OF RISING TEMPERATURES SHOULD CONTINUE EASTWARD THROUGH SUNRISE. ALONG WITH THE WARM ADVECTION...IT APPEARS THAT THE RUC MODEL HAS A VERY GOOD HANDLE ON H850 TO H700 LIFTING OCCURRING OVER SOUTHEASTERN SASKATCHEWAN/SOUTHWEST MANITOBA/NORTHERN NORTH DAKOTA. THIS MODEL WAS DEPICTING LIGHT PRECIPITATION OVER THIS SAME AREA AROUND MIDNIGHT...AND IT CONTINUES/ADVECTS IT EASTWARD DURING THE REST OF THE NIGHTTIME HOURS. CURRENT RADAR LOOPS VALIDATING AT LEAST SOME ENHANCED CLOUDS AND/OR LIFT OCCURRING...SO WILL KEEP A MENTION OF FLURRIES FOR THIS TIME PERIOD OVER NORTH CENTRAL TO THE JAMESTOWN AREA THROUGH SUNRISE. THE 06Z NAM AS WELL AS THE 00Z ECMWF AND GFS MODELS ARE NOW DEPICTING LIGHT PRECIPITATION OVER NORTHEASTERN NORTH DAKOTA FROM 6 AM TO NOON TIME FRAME. THIS APPEARS TO BE THE RESULT OF BOTH WARM ADVECTION LIFTING AT H850/H700 AS WELL AS REINFORCEMENT FROM AN UPPER LEVEL SHORTWAVE MOVING SOUTHEAST OUT OF MANITOBA. ADDED A MENTION OF CHANCE OF LIGHT SNOW THIS MORNING IN THE BOTTINEAU/TURTLE MOUNTAIN/HARVEY AREA. CONTINUED WARM ADVECTION THROUGH THE DAY UNTIL A COLD FRONT DIVES SOUTHEAST OUT OF SASKATCHEWAN THIS AFTERNOON SWEEPING ACROSS THE STATE AND REACHING THE JAMES RIVER VALLEY LATE AFTERNOON/EVENING. SOUTH WINDS AHEAD OF THE FRONT WILL BECOME NORTHWEST AT AROUND 15 MPH. EXPECTING HIGH TEMPERATURES TO REACH INTO THE 20S OVER NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THROUGH THE JAMES RIVER VALLEY...WITH TEMPERATURES IN THE 30S MAINLY SOUTH AND WEST OF THE MISSOURI RIVER. THE FAR SOUTHWEST MAY SEE TEMPERATURES REACH INTO THE LOWER 40S. THE COLD FRONT WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH PRESSURE SYSTEM...AND EXPECTING LOWS TONIGHT FROM THE SINGLE DIGITS NORTH TO LOWER TEENS SOUTH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CST WED NOV 27 2013 FORECAST HIGHLIGHTS IN THE LONG TERM PERIOD WILL BY MAINLY DRY CONDITIONS THROUGH SATURDAY NIGHT...FOLLOWED BY A POSSIBLE VERY ACTIVE WEATHER PERIOD SOMETIME FROM SUNDAY INTO THE MIDDLE PORTIONS OF NEXT WEEK. THE EXTENDED PERIOD BEGINS THURSDAY MORNING WITH STRONG NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS AND A SFC RIDGE OF HIGH PRESSURE EXTENDING FROM NORTH OF MANITOBA SOUTH THROUGH THE DAKOTAS. BOTH THE 00Z NAM/GFS CONTINUE TO INDICATE LOW STRATUS FROM WEDNESDAY NIGHT PERSISTING INTO THURSDAY MORNING ACROSS MUCH OF WEST AND CENTRAL NORTH DAKOTA WITH THE SFC RIDGE. COUPLED WITH SUBTLE MID/UPPER LEVEL SUPPORT...OPTED TO CONTINUE THE ISOLATED FLURRY MENTION FROM WED NIGHT INTO MID MORNING THURSDAY. WILL SEE A PATTERN CHANGE STARTING ON FRIDAY AS UPPER LEVEL LOW PRESSURE OVER EASTERN CANADA THURSDAY LIFTS MORE NORTHEAST TOWARDS WESTERN GREENLAND FRI-SAT. THIS TRANSITIONS OUR FLOW ALOFT FROM STRONG NORTHWESTERLY TO A WEAKER NORTHWESTERLY BY SATURDAY...AND EVENTUALLY QUASI-ZONAL BY SUNDAY. WILL MAINTAIN DRY CONDITIONS AND A SLOW WARM-UP UNDER THIS FLOW PATTERN THROUGH SAT NIGHT. AS THIS CHANGE IS OCCURRING...STRONG UPPER LOW OVER ALASKA ON THURSDAY WILL MOVE SLOWLY SOUTHEAST ALONG THE CANADIAN PACIFIC SHORE SATURDAY NIGHT INTO SUNDAY...THEN INTO THE PACIFIC NORTHWEST BY EARLY MONDAY. LEAD EMBEDDED IMPULSES WITHIN THIS FEATURE MAY BRING PRECIPITATION TO THE DAKOTAS AS EARLY AS SUNDAY DAYTIME (00Z ECMWF)...OR MAY HOLD OFF UNTIL MONDAY (00Z GFS). THUS MODELS STILL SHOWING LOTS OF UNCERTAINTY ONLY 4-5 DAYS OUT. WAA AHEAD OF THIS SYSTEM WOULD SUPPORT A VARIETY OF PRECIPITATION TYPES...DEPENDING WHETHER WE SEE PRECIP AT NIGHT OR IN THE DAYTIME. UNCERTAINTY COMPOUNDS AS WE GO FORWARD INTO THE EARLY TO MIDDLE PORTIONS OF NEXT WEEK AS THE UPPER LOW EVOLVES. THE LATEST GFS PRODUCES SPLIT FLOW DEVELOPING MONDAY NIGHT INTO TUESDAY...WITH THE BULK OF ASSOCIATED PRECIPITATION OFF TO OUR NORTH IN CANADA. THE LATEST 00Z ECMWF (MUCH SLOWER THAN THE 12Z ECMWF) MAINTAINS A CLOSED SYSTEM AND DOES IMPACT WEST AND NORTH CENTRAL PARTS OF THE STATE WITH WINTER WEATHER. ALL SOLUTIONS BRING IN MUCH COLDER AIR SOMETIME TUESDAY OR WEDNESDAY. WILL CONTINUE TO MONITOR IN THE COMING DAYS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1244 AM CST WED NOV 27 2013 VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA TONIGHT. A PACIFIC FRONT WILL PUSH THROUGH THE STATE WEDNESDAY GENERATING A NORTHWESTERLY WIND SHIFT AND MVFR CIGS NORTH AND WEST (KISN-KMOT-KDIK) AFTER 18Z AND REACHING KBIS WEDNESDAY MID-AFTERNOON. LOW CONFIDENCE IN TIMING OF MVFR CIGS REACHING TAF SITES AFTER WINDS SHIFT TO NORTHWEST. WIND SHIFT AND MVFR CIGS NOT EXPECTED TO REACH KJMS UNTIL LATE AFTERNOON OR EVENING. MVFR CIGS EXPECTED TO PERSIST BEYOND THE END OF THE TAF PERIOD (06Z THU). && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JV LONG TERM...NH AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1244 AM CST WED NOV 27 2013 .UPDATE... ISSUED AT 1244 AM CST WED NOV 27 2013 SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHWESTERN SASKATCHEWAN/NORTH CENTRAL MONTANA. SOUTH WINDS AHEAD OF THE SYSTEM HAD DEVELOPED OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENING HOURS. STRONG WARM ADVECTION OCCURRING OVER THE WESTERN HALF OF THE STATE AHEAD OF THIS SYSTEM. REGARDING TEMPERATURES...READINGS HAVE RISEN INTO THE LOWER 20S ALREADY ACROSS FAR WESTERN NORTH DAKOTA...AND INTO THE TEENS OVER WESTERN PORTIONS OF CENTRAL NORTH DAKOTA. THIS TREND OF RISING TEMPERATURES SHOULD CONTINUE EASTWARD DURING THE OVERNIGHT HOURS...THUS STEADY OR RISING TEMPERATURES IS FORECAST FOR THE REST OF TONIGHT. ALONG WITH THE WARM ADVECTION...IT APPEARS THAT THE RUC MODEL HAS A VERY GOOD HANDLE ON H850 TO H700 LIFTING OCCURRING OVER SOUTHEASTERN SASKATCHEWAN/SOUTHWEST MANITOBA/NORTHERN NORTH DAKOTA. THIS MODEL WAS DEPICTING LIGHT PRECIPITATION OVER THIS SAME AREA AROUND MIDNIGHT...AND IT CONTINUES/ADVECTS IT EASTWARD DURING THE REST OF THE NIGHTTIME HOURS. CURRENT RADAR LOOPS VALIDATING AT LEAST SOME ENHANCED CLOUDS AND/OR LIFT OCCURRING...SO ADDED A MENTION OF FLURRIES FOR THIS TIME PERIOD OVER NORTH CENTRAL TO THE JAMESTOWN AREA FOR THE REST OF TONIGHT. UPDATE ISSUED AT 939 PM CST TUE NOV 26 2013 TEMPERATURES HAVE RADIATED TO THE LOW SINGLE DIGITS ALONG THE CENTER OF THE SURFACE HIGH PRESSURE RIDGE AXIS EXTENDING FROM THE TURTLE MOUNTAINS INTO THE JAMES RIVER VALLEY. AS OF 9 PM CST...HARVEY REPORTED A TEMPERATURE OF ONE DEGREE ABOVE ZERO. GIVEN THE CURRENT OBS/TRENDS...ADJUSTED OVERNIGHT LOWS DOWN A CATEGORY...ESPECIALLY OVER AREAS EAST OF HIGHWAY 83 PROXIMATE TO THE SURFACE RIDGE AXIS. OTHERWISE...THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 644 PM CST TUE NOV 26 2013 SURFACE HIGH PRESSURE HAS CRESTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING AND WILL CONTINUE TO PUSH EAST TONIGHT. AS A RESULT...RETURN FLOW WILL DEVELOP AS LOW PRESSURE MOVES INTO SOUTHERN SASKATCHEWAN. TEMPERATURES SHOULD CONTINUE TO DROP IN AREAS OF LIGHT WIND THIS EVENING...THEN HOLD STEADY OR EVEN INCREASE IN SOME SPOTS AS SOUTHERLY FLOW DEVELOPS AFTER MIDNIGHT. THE CURRENT FORECAST CAPTURES THIS SCENARIO SO ONLY MADE MINOR ADJUSTMENTS TO THE SENSIBLE WEATHER GRIDS FOR THIS UPDATE. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 240 PM CST TUE NOV 26 2013 SURFACE HIGH PRESSURE WILL DRIFT EAST OVERNIGHT AS WEAK RETURN FLOW BECOMES ESTABLISHED IN WESTERN NORTH DAKOTA. EARLY MORNING LOWS SHOULD BE HELD UP IN THE TEENS SOUTHWEST...BUT DROP INTO THE SINGLE DIGITS ELSEWHERE. A FRONTAL BOUNDARY AND ASSOCIATED WEAK 500MB WAVE WILL SKIRT NORTHEAST NORTH DAKOTA WEDNESDAY MORNING. HAVE KEPT SLIGHT CHANCE POPS IN PLACE FOR THE TURTLE MOUNTAINS AREA DURING THE MORNING HOURS. MILDER PACIFIC AIR WILL SPREAD INTO WESTERN AND CENTRAL PORTIONS OF THE FORECAST AREA ON WEDNESDAY AND BOOST AFTERNOON TEMPERATURES INTO THE 30S SOUTH AND EAST OF THE MISSOURI RIVER. READINGS IN THE 20S ARE FORECAST NORTH AND EAST OF THE RIVER. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 240 PM CST TUE NOV 26 2013 A PROGRESSIVE FLOW REMAINS ON TRACK THROUGH THE EXTENDED WITH NO ORGANIZED PRECIPITATION AREAS UNTIL LATE IN THE PERIOD...WITH THOSE DETAILS REMAINING UNCERTAIN IN REGARDS TO SNOW PLACEMENT AND DURATION. HOWEVER THE POTENTIAL FOR UNSETTLED WEATHER STILL LOOKS TO OCCUR IN THE SUNDAY THROUGH TUESDAY TIME FRAME...WITH MUCH COLDER AIR BY MIDWEEK NEXT WEEK. WEDNESDAY NIGHT THROUGH SATURDAY...AN H85 COLD POCKET OF AIR AND ASSOCIATED SWATH OF STRATUS IS FORECAST TO INFILTRATE NORTHERN NORTH DAKOTA WEDNESDAY EVENING AND FILTER SOUTH WEDNESDAY NIGHT. THERE COULD BE SOME FLURRIES GENERATED WITHIN THE STRATUS LAYER WITH FORECAST 925-850MB LAPSE RATES BETWEEN 6C AND 7C/KM WEDNESDAY NIGHT AND THUS HAVE INCLUDED ISOLATED FLURRIES IN THE GRIDS. OVERALL HAVE CONTINUED WITH THE PREVIOUS FORECAST THINKING WITH HIGHER SKY GRID NUMBERS WEDNESDAY NIGHT AS THE 12Z NAM/GFS 925MB RH FIELD ALSO REMAIN CONSISTENT WITH THIS IDEA. FOR THURSDAY INTO SATURDAY...WEAK WARM AIR ADVECTION WILL YIELD A SLIGHT WARMUP UNDER DRY CONDITIONS. HIGH TEMPERATURES THANKSGIVING WILL RANGE FROM 15F TO 25F...WITH HIGHS RISING TO BETWEEN 25F TO 40F SATURDAY. SUNDAY THROUGH TUESDAY...STRONG UPPER LOW DROPPING INTO BRITISH COLUMBIA WITH THE AIRMASS ORIGINALLY ROOTED IN EASTERN RUSSIA. LARGE POCKET OF H85 TEMPS BETWEEN -25C TO -30C WILL HOVER OVER BRITISH COLUMBIA AND ALBERTA EARLY NEXT WEEK WITH SUCCESSIVE CHUNKS BREAKING OFF AND PUSHING TOWARD NORTH DAKOTA LATE IN THE LONG TERM PERIOD. THIS WILL YIELD MUCH COLDER AIR BY MID TO LATE WEEK. IN TERMS OF SNOWFALL POTENTIAL...A CHANCE OF SNOW REMAINS IN THE FORECAST BEGINNING SUNDAY...BUT MORE SO MONDAY AND TUESDAY. THE GFS AND ECMWF REMAIN AT ODDS WITH A DRY SLOT LOCATION AND HENCE IT IS DIFFICULT TO HAVE CONFIDENCE ON THE DURATION AND PLACEMENT OF THE SNOW. WILL NOT MAKE ANY CHANGES TO THE ALLBLEND SOLUTION WHICH BASICALLY HAS A WIDESPREAD CHANCE OF SNOW MONDAY AND TUESDAY. A SLIGHT CHANCE OF SNOW CONTINUES FOR SUNDAY...WITH POPS INCREASING THEREAFTER. WILL CONTINUE TO KEEP THE MENTION GOING IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW WITH MORE DETAILS TO FOLLOW AS WE GET CLOSER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1244 AM CST WED NOV 27 2013 VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA TONIGHT. A PACIFIC FRONT WILL PUSH THROUGH THE STATE WEDNESDAY GENERATING A NORTHWESTERLY WIND SHIFT AND MVFR CIGS NORTH AND WEST (KISN-KMOT-KDIK) AFTER 18Z AND REACHING KBIS WEDNESDAY MID-AFTERNOON. LOW CONFIDENCE IN TIMING OF MVFR CIGS REACHING TAF SITES AFTER WINDS SHIFT TO NORTHWEST. WIND SHIFT AND MVFR CIGS NOT EXPECTED TO REACH KJMS UNTIL LATE AFTERNOON OR EVENING. MVFR CIGS EXPECTED TO PERSIST BEYOND THE END OF THE TAF PERIOD (06Z THU). && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...RP KINNEY LONG TERM...KS AVIATION...JV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
408 AM EST WED NOV 27 2013 .SYNOPSIS... WINTER STORM SYSTEM LIFTS TO THE NORTHEAST. UPSLOPE SNOW TODAY AND TONIGHT. HIGH PRESSURE BUILDING IN ON THANKSGIVING DAY AND LINGERING FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... GENERALLY FOLLOWING THE HRRR MODEL IN REGARDS TO THE EVOLUTION OF THE SYNOPTIC SNOW OVER THE NEXT FEW HOURS INTO THE DAWN HOURS. DEFORMATION ZONE PROVIDING THE MAIN FORCING OF THE SNOW AT THIS POINT WILL DRIFT TO THE EAST THROUGH 12Z TODAY...AND CARRY THE BETTER CHANCES FOR SNOW WITH IT. THERE WAS A PATCH OF DRIER AIR TO CONTEND WITH A FEW HOURS AGO DURING THE TEMPERATURE TRANSITION TO BELOW FREEZING VALUES...AND HAVE GOTTEN OFF TO A SLOW START IN TERMS OF ACCUMULATIONS. THIS SPARKS A FEW CONCERNS ABOUT MEETING THE PREVIOUSLY FORECASTED AMOUNTS...BUT WILL NOT GIVE UP ON IT JUST YET AS WE STILL HAVE A FEW HOURS TO GET SOME ACCUMULATIONS OUT OF THIS. AS THE MAIN SYNOPTIC FORCING FOR THIS EVENT DEPARTS WITH THE DEFORMATION ZONES PUSHING EAST OF THE MOUNTAINS AND THE 500MB TROUGH AXIS PASSING LATER TODAY...THE SET UP LOOKS FAIRLY DECENT TO HAVE CONVECTIVE SNOW FOR THE FIRST PART OF TODAY. LOOKING AT A CROSS SECTION ORIENTED TO THE MEAN LOW LEVEL WIND SHOWS GOOD SATURATION INTO THE CRYSTAL GROWTH LAYER...FED BY NORTHWEST FLOW THROUGH THE LOW LEVELS. FIGURE THE NATURE OF THE SNOW WILL BE OFF AND ON AT THIS POINT...BUT A QUICK INCH HERE AND THERE WILL BE POSSIBLE THROUGH 18Z OR 20Z TODAY FOR THE LOWLANDS. THIS POTENTIAL INCREASED IN THE MOUNTAINS IN THE BETTER UPSLOPE CONDITIONS. AFTER THAT...IT WILL MAINLY BE A MOUNTAIN EVENT ONLY THAT WILL SLOWLY FADE DURING THE OVERNIGHT PERIOD. WINDS WILL BE ON THE INCREASE OUT OF THE NORTHWEST TODAY...WITH GUSTS UP TO 30KTS AT TIMES. BLOWING SNOW OVER THE HIGHEST RIDGES IS LIKELY LATER TODAY AND TONIGHT. DID NOT GET CUTE WITH THE TEMPERATURES TODAY. MAX TEMPERATURES MAY BE RIGHT AT DAWN AS THE COLDER AIR COMES IN...AND THEN WILL CHILL A COUPLE DEGREES...BUT COULD MAKE A DEGREE OR TWO RECOVERY THROUGH THE AFTERNOON TOWARDS THE MORNING VALUES. IN THE END...HIGHS AROUND 30F WILL RULE FOR MUCH OF THE AREA...AND GETTING COLDER FOR THE MOUNTAINS BY EVENING. OVERNIGHT...HAVE SNOWSHOE IN THE SINGLE DIGITS...WITH OTHER LOCATIONS FALLING INTO THE TEENS TO LOWER 20S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... UPPER PATTERN ACROSS THE UNITED STATES RETURNS TO A ZONAL FLOW THROUGH THE EARLY WEEKEND. THIS WILL KEEP THE COLDEST AIR WITH CANADIAN HIGH PRESSURE CENTERS UP IN CANADA. EVEN THOUGH UPPER IMPULSES WILL TRACK EASTWARD THROUGH THE FLOW...THEY WILL BE WEAK. THIS..IN COMBINATION WITH GULF OF MEXICO MOISTURE BEING CONFINED ACROSS THE SOUTHERN STATES...WILL BRING DRY CONDITIONS AND A DAY TIME WARMING TREND. HIGH TEMPERATURES IN THE 30S THURSDAY WILL REACH WELL INTO THE 40S FRIDAY AND SATURDAY. HOWEVER...THE DRY AIR ALONG WITH LACK OF CLOUDS...WILL ALLOW FOR COLD NIGHT TIME READINGS WELL BELOW FREEZING. THUS...LOOK FOR DRY WEATHER AND A LARGE RANGE IN DIURNAL TEMPERATURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... A RATHER TRANQUIL ZONAL FLOW WITH SOME WEAK TROUGH APPROACHING LATE IN THE WEEKEND. WILL CONTINUE BRINGING BACK SOME CHANCE POPS FOR LIGHT RAIN SUNDAY NIGHT AND BECOMING MORE WIDESPREAD MONDAY BEFORE DIMINISHING POPS MONDAY NIGHT. NOT ANY STRONG FEATURES OR FRONTS EXPECTED DURING THIS PERIOD. NO BIG DEVIATIONS FROM HPC MEDIUM RANGE GROUP TEMPERATURES. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... IFR CONDITIONS DOMINATE THE FRONT END OF THE TAFS WITH THE RAIN FINALLY CHANGING OVER TO SNOW. THERE COULD BE SOME BOUNCING OF THE OBSERVATIONS IN AND OUT OF THE HEAVIER BATCHES OF SNOW PUSHING THROUGH. BKW TO LIKELY STAY LIFR OVER THE NEXT FEW HOURS. ALL LOCATIONS SHOULD BENEFIT FROM CEILING RISES AS THE WINDS BECOME GUSTY OUT OF THE NORTHWEST. WILL STILL HAVE TROUBLE GETTING OUT OF THE IFR CATEGORY...BUT SHOULD HAPPEN LATER TODAY. AFTER SUNRISE TODAY...MUCH OF THE SYNOPTIC SCALE SNOW WILL HAVE MOVED OUT AS WE LOSE THE BULK OF THE DEEPER MOISTURE. HOWEVER...CONVECTIVE SNOW SQUALLS ARE POSSIBLE THROUGH 20Z TODAY...WHICH SUPPORTS THE EXTENSION OF THE IFR VISIBILITIES. HOWEVER...THESE WILL OFF AND ON IN NATURE...AND WILL LIKELY NEED WIDE TEMPOS TO COVER FOR PERIODS WHEN THE SNOW STOPS. VFR CONDITIONS CREEP IN LATER THIS EVENING FOR HTS...EKN...PKB...AND BKW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: VISIBILITY RESTRICTIONS COULD VARY WITH SNOW. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE WED 11/27/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 CRW CONSISTENCY M H H H H M M M L L L L HTS CONSISTENCY H H H M M L H H H H M H BKW CONSISTENCY M M M H H L L L L L L L EKN CONSISTENCY M M M M M M M M M L L L PKB CONSISTENCY M M M M M M L L L L L H CKB CONSISTENCY H H H H H M M M M L L L AFTER 06Z THURSDAY... IFR CONDITIONS EXPECTED WEDNESDAY NIGHT IN SNOW DUE TO A LINGERING WINTER STORM SYSTEM...PARTICULARLY ACROSS THE MOUNTAINS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR WVZ035>037. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ008>011-013>020-024>034-039-040. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR WVZ038-046- 047. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR WVZ005>007. OH...NONE. KY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR KYZ105. VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...26 SHORT TERM...JMV LONG TERM...KTB AVIATION...26
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1015 AM EST WED NOV 27 2013 .UPDATE (TODAY THROUGH THANKSGIVING DAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A HIGHLY AMPLIFIED UPPER LEVEL PATTERN IN PLACE OVER THE CONUS...HIGHLIGHTED BY LONGWAVE RIDGING OVER THE INTER-MOUNTAIN WEST AND A DEEP/SHARP LONGWAVE TROUGH OVER THE EASTERN HALF OF THE NATION. THE TROUGH AXIS EXTENDS FROM THE EASTERN GREAT LAKES TO THE SOUTHEAST COAST. THE STRONG SOUTHERN STREAM IMPULSE WHICH BROUGHT THE SHOWERS AND STORMS TO THE AREA LAST NIGHT IS NOW PIVOTING OVERHEAD AND WILL QUICKLY BE EXITING TO OUR NORTHEAST AND UP THE EASTERN SEABOARD DURING THE AFTERNOON HOURS. WV IMAGERY SHOWS A BROAD EXPANSE OF SUBSIDENCE/DRYING IN THE MID/UPPER LEVELS BEHIND THIS SHORTWAVE AND QUICKLY SPREADING OVER OUR HEADS. THIS IS ONE OF THOSE SITUATIONS WHERE THE 12Z KTBW SOUNDING PROFILE WAS UNREPRESENTATIVE OF OUR ATMOSPHERIC COLUMN WITHIN A VERY SHORT TIME...AS ITS RELEASE WAS RIGHT BEFORE THE PASSING OF THE SHORTWAVE AXIS. ALTHOUGH NO DOUBT NOT AN EXACT REPRESENTATION...THE KTLH SOUNDING PROFILE IS LIKELY A CLOSER MATCH TO WHAT WE SEE OVERHEAD LATE THIS MORNING IN TERMS OF MOISTURE. AT THE SURFACE...COLD FRONT HAS PASSED OFF TO THE EAST OF THE PENINSULA WITH GUSTY NORTHWEST WINDS IN ITS WAKE. DEWPOINTS HAVE BECOME MORE COMFORTABLE IN THE PAST SEVERAL HOURS...DROPPING FROM THE MID 60S DOWN INTO THE 50S. THE LAST RESIDUAL SYNOPTIC LIFT (EXITING NOW) ALONG WITH A LONG CAA FETCH OVER THE RELATIVELY WARM GULF WATERS IS PRODUCING SCT-BKN STRATOCU WITHING THE NW FLOW...AND THE LOW LEVEL LAPSE RATES ALONG WITH THE LAST LARGE SCALE FORCING IS JUST ENOUGH FOR A FEW RAINDROP/SPRINKLES MOVING ASHORE. DO NOT EXPECT ANY MEASURABLE PRECIP OUT OF ANY OF THESE SPRINKLES FROM THIS POINT ON...AND THE BUILDING DRY AIR IN THE LOWER LEVELS ALONG WITH LOSS OF FORCING SHOULD END ANY LEFTOVER SPRINKLES BY THE AFTERNOON HOURS. PERIODS OF SCT-BKN CLOUDS MAY HOWEVER CONTINUE TO ROLL ASHORE UNTIL THE WINDS VEER AROUND MORE TO THE NORTH THIS EVENING. TEMPERATURES THROUGH EARLY TO MID AFTERNOON WILL NOT CHANGE MORE THAN A FEW DEGREES AT MOST LOCATIONS AND THEN BEGIN TO FALL DURING THE LATER AFTERNOON HOURS AS THE SUN ANGLE LESSENS AND CAA CONTINUES. THE COLDEST NIGHT OF THE SEASON SO FAR IN STORE FOR MOST LOCATIONS. A FREEZE WATCH REMAINS IN EFFECT FOR THE LATE NIGHT HOURS FOR HERNANDO...SUMTER...CITRUS...AND LEVY COUNTIES. THE TEMPERATURES WILL BE RE-EVALUATED ONE LAST TIME WITH THE 12Z GUIDANCE PACKAGE AND DECISIONS WILL BE MADE BY MID-AFTERNOON ON WHETHER TO UPGRADE ANY OF THESE ZONES TO A FREEZE WARNING. EVEN OUTSIDE OF THESE ZONES... TEMPERATURES WILL BECOME QUITE CHILLY BY SUNRISE WITH WIDESPREAD MID 30S TO LOWER 40S. TEMPERATURES ALONG THE IMMEDIATE COAST FROM PINELLAS COUNTY SOUTHWARD SHOULD REMAIN IN THE 40S WITH MORE INFLUENCE FROM THE WATER. WINDS WILL DIMINISH FROM THE GUSTY NATURE TODAY...BUT WITH THE HIGH WELL TO OUR NORTH...DO NOT ANTICIPATE A DECOUPLING OF THE BOUNDARY LAYER AND WINDS GOING CALM. THEREFORE AT LEAST SOME MOMENTUM WILL PUSH WIND CHILLS AROUND SUNRISE DOWN INTO THE LOWER/MID 30S FOR ALL BUT THE FAR SOUTHERN ZONES. FROM HERNANDO/SUMTER COUNTY NORTHWARD...WIND CHILLS ARE FORECAST TO BRIEFLY DROP INTO THE 20S. SO EITHER WAY...IT WILL BE CHILLY MORNING FOR ANYONE WITH OUTDOOR ACTIVITIES WITHIN A FEW HOURS EITHER SIDE OF SUNRISE. THANKSGIVING DAY... A PLEASANT/FAIR DAY IN STORE AFTER THE CHILLY START. A DEEP DRY ATMOSPHERIC COLUMN WITHIN ZONAL FLOW ALOFT WILL KEEP OUR FORECAST RAIN FREE WITH A NORTHEAST WIND SOUTH OF A RIDGE AXIS OVER THE CAROLINAS. THIS NORTHEAST FLOW WILL BRING SOME LOW LEVEL MOISTURE IN FROM THE ATLANTIC BY THE AFTERNOON. THEREFORE LOOKING FOR MOSTLY SUNNY SKIES IN THE MORNING AND THEN A MIX OF SUN AND CLOUDS UNDER A SCT CU FIELD FOR THE AFTERNOON. SAFE TRAVELS FOR THE BUSIEST TRAVEL DAY OF THE YEAR. THOSE TRAVELING ON THE I-4 AND FLORIDA I-75 CORRIDORS THE REMAINDER OF THE DAY CAN EXPECT DRY CONDITIONS...BUT RATHER GUSTY WINDS (UP TO 25-30 MPH AT TIMES) OUT OF THE NORTHWEST. ENJOY! && .AVIATION... BKN MAINLY VFR CIGS...BUT WITH OCNL MVFR CIGS IN VCSH...THROUGH MID-MORNING. BECOMING SCT DURING THE DAY THEN SKC AROUND SUNSET. GUSTY W-NW WINDS DIMINISH IN THE EVENING AND BEGIN TO VEER TO NORTHERLY. && .MARINE... SMALL CRAFT ADVISORIES REMAIN IN EFFECT THROUGH EARLY THURSDAY MORNING. WINDS HAVE BECOME NORTHWEST IN THE WAKE OF A COLD FRONT AND ARE AT HIGH END ADVISORY CRITERIA...WITH SOME NEAR GALE FORCE GUSTS FOR THE NEXT SEVERAL HOURS. WAVE HEIGHTS HAVE ALSO INCREASE TO BETWEEN 8-11 FEET. WINDS WILL SHIFT NORTH TONIGHT AND THEN NORTHEAST ON THURSDAY WITH SOME IMPROVEMENT IN CONDITIONS...ALTHOUGH PERIODS OF CAUTIONARY LEVEL WINDS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... TPA 68 41 65 52 / 10 0 0 0 FMY 73 46 70 55 / 10 0 0 10 GIF 70 40 67 52 / 10 0 0 10 SRQ 69 43 68 53 / 10 0 0 0 BKV 65 34 63 44 / 10 0 0 0 SPG 68 47 65 56 / 10 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR CITRUS-HERNANDO-LEVY-SUMTER. LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS EVENING FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO- HIGHLANDS-HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO- PINELLAS-POLK-SARASOTA-SUMTER. RIP CURRENT RISK THROUGH THURSDAY MORNING FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. HIGH SURF ADVISORY UNTIL 7 AM EST THURSDAY FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM- TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR TAMPA BAY WATERS. && $$ UPDATE/MARINE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
523 AM EST WED NOV 27 2013 .UPDATE... ISSUED AT 1034 PM EST TUE NOV 26 2013 MAIN FCST CONCERNS OVERNIGHT ARE HEADLINES AND LES TRENDS. WITH KDLH RADAR SHOWING LES BANDS STREAMING INTO FAR WRN UPPER MI TOWARD THE KIWD AREA...SNOW LIKELY HAS HAS BEEN FAIRLY HVY IN THAT AREA THIS EVENING. BANDS HAVE BEEN MOVING THOUGH...PREVENTING MORE SUBSTANTIAL ACCUMULATION. OVER ERN LAKE SUPERIOR...LES HAS BECOME MORE WIDESPREAD WITH A GENERAL UPTICK IN INTENSITY UNDER STRONGER LOW-LEVEL CONVERGENCE ALONG SOUTHWARD MOVING SFC TROF. HOWEVER... WITH SHORTWAVE TROF NOW SLIPPING E OF LAKE SUPERIOR PER WATER VAPOR IMAGERY...HAVE CONCERN THAT SNOW ACCUMULATIONS NEED TO BE TONED DOWN ACROSS THE BOARD OVERNIGHT/WED MORNING AS MODEL GUIDANCE SHOWS RATHER HEALTHY LARGE SCALE QVECTOR DIVERGENCE DOMINATING THRU WED MORNING BEHIND WAVE. SO...APART FROM LOCALIZED LOW-LEVEL CONVERGENCE/UPSLOPE TERRAIN ENHANCEMENT...LES MAY MOSTLY BE ON THE LIGHTER SIDE. ON THE PLUS SIDES...DGZ SHOULD BE FAIRLY WELL CENTERED WITHIN THE UPWARD MOTION ZONE TO FLUFF UP SNOW ACCUMULATIONS...AND UPSTREAM 00Z CWPL SOUNDING SHOWED A DEEP MOISTURE PROFILE THRU ABOUT 11KFT OR SO. HOWEVER...GIVEN THE LARGE SCALE NEGATIVES...GENERALLY LOWERED SNOW ACCUMULATIONS FROM THIS POINT FORWARD. THE WARNING FOR MARQUETTE COUNTY MAY BE TOUGH TO ACHIEVE. IF ANY PLACE DOES REACH WARNING CRITERIA...IT WILL PROBABLY BE THE HIGHER TERRAIN N AND NW OF NEGAUNEE WHERE UPSLOPE IS MAXIMIZED. ADVY IS PRETTY MARGINAL FOR THE KEWEENAW OVERNIGHT WITH WINDS BECOMING A LESS FAVORABLE NORTHERLY DIRECTION. STILL MAY SEE A FEW HEAVIER SNOW BANDS TRAVERSE THE KEWEENAW...AND GUSTY WINDS...MAINLY ALONG THE LAKE...WILL LEAD TO BLSN. OVER THE FAR W...PRECONDITIONING FROM LAKE NIPIGON MAY STILL FAVOR MORE PERSISTENT HEAVIER SNOW...MAINLY FROM THE PORCUPINE MTNS TO KIWD VCNTY AS THE NIGHT WEARS ON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 505 PM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON. AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED 8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES. EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7 INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4 OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES WARNING FOR TONIGHT THROUGH WEDNESDAY. FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA. INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER OFF WED AFTERNOON FROM WEST TO EAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 517 AM EST WED NOV 27 2013 THURSDAY...MODELS WERE IN GOOD AGREEMENT...SHOWING A CLIPPER SHORTWAVE TROUGH WITH MODERATE TO STRONG 700-300 MB QVECTOR CONV SLIDING THROUGH THE NRN GREAT LAKES. THIS WILL SUPPORT A CHANCE OF LIGHT SNOW ACROSS THE CWA BUT WITH SNOWFALL AMOUNTS OF A HALF INCH OR LESS. WITH A WEAK WIND FIELD ACROSS THE AREA AS THE SFC LOW MOVES THROUGH THE CWA...THE HIGH RES MODELS HAVE BEEN CONSISTENT IN DEPICTING A MESO-LOW OVER WRN LAKE SUPERIOR WITH A TROUGH AND ASSOCIATED AREA OF STRONG LOW LEVEL CONV THROUGH THE NRN KEWEENAW PENINSULA. CONFIDENCE IS MODERATE TO HIGH THAT SOME TYPE OF ENHANCED MESO-SCALE SNOWBAND WILL DEVELOP BUT IS MUCH LOWER ON WHERE IT WILL BE LOCATED. WITH DEEP MOISTURE...850 MB TEMPS TO AROUND -15C...INVERSION HEIGHTS TO 10K FT AND FAVORABLE POSITION OF THE DGZ...SNOWFALL RATES OF SEVERAL INCHES PER HOUR WOULD BE POSSIBLE WITH THIS FEATURE. SINCE CONSIDERABLE UNCERTAINTY REMAINS WITH THE POSITION ANY NARROW SNOWBAND...MORE GENERAL 2 TO 5 INCH SNOW AMOUNTS ACROSS KEWEENAW COUNTY WERE INCLUDED IN THE FCST. THERE MAY BE THE POTENTIAL FOR AMOUNTS OF A NARROW BAND OF 8 INCHES OR MORE. DUE TO ONGOING HEADLINES...AND THE UNCERTAINTY MENTIONED ABOVE...NO ADDITIONAL HEADLINES WERE ADDED AT THIS TIME BUT THE SNOW POTENTIAL WILL BE HIGHLIGHTED IN THE HWO. THURSDAY NIGHT...AS THE SFC LOW AND TROUGH SWING THROUGH THE WRN CWA IN THE WAKE OF THE SHRTWV...A BRIEF PERIOD OF HEAVIER LAKE ENHANCED SNOW MAY ALSO MOVE THROUGH THE WEST BEFORE THE STRONGER LOW LEVEL CONV WEAKENS. THE MODELS SHOW GREATER DIFFERENCES IN HANDLING THE POSITION OF THE LOW AND LOW LEVEL WINDS AS THE GFS/ECMWF SHOW MAINLY LIGHT OR OFFSHORE WINDS OVER THE NORTH WHILE THE NAM PUSHES NORTH WINDS INTO N CNTRL UPPER MI AS A MORE PROMINENT LAKE INDUCED LOW DEVELOPS OVER SE LAKE SUPERIOR. SO...ONLY CHANCE POPS WERE MENTIONED FOR AREAS AWAY FROM THE KEWEENAW. FRIDAY...THERE MAY BE SOME LINGERING LES OVER THE NORTH EARLY BEFORE WINDS BACK TO THE SW. 850 MB WAA WILL THEN STRENGTHEN AS WEAK MID LEVEL RIDGING MOVES IN AND THE SFC HIGH PRES BUILDS INTO THE ERN LAKES. HOWEVER...SFC TEMPS WILL ONLY REBOUND INTO THE MID AND UPPER 20S. SAT...GFS/ECMWF/GEM SUGGEST ANOTHER CLIPSER SHORTWAVE TROUGH WILL SLIDE THROUGH THE NRN GREAT LAKES BRINGING A CHANCE OF LIGHT SNOW. HOWEVER...THE STRONGER FORCING AND SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR. SUN-TUE...A RELATIVELY QUIET PERIOD IS EXPECTED WITH WEAK A WEAK SFC RIDGE AND INCREASING MID LEVEL RIDGING PREVAILING. MAX READINGS WILL CLIMB INTO THE LOWER TO MID 30S WITH LOWS GENERALLY IN THE 20S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1152 PM EST TUE NOV 26 2013 LAKE EFFECT SNOW SHOWERS WILL CONTINUE AT KIWD/KCMX/KSAW THRU MUCH IF NOT ALL OF THIS FCST PERIOD. AS IS TYPICAL FOR LAKE EFFECT... CONDITIONS WILL VARY CONSIDERABLY FROM VFR TO AS LOW AS IFR OR EVEN BRIEF LIFR. LOWEST CONDITIONS WILL BE MORE COMMON AT KIWD/KSAW DUE TO UPSLOPING NORTHERLY WIND. CONDITIONS WILL GENERALLY VARY BTWN MVFR AND IFR THRU THE MORNING...WITH LIFR POSSIBLE AT TIMES... ESPECIALLY AT KSAW EARLY ON IN THE FCST PERIOD. AT KCMX...NORTHERLY WINDS ARE GENERALLY NOT AS FAVORABLE FOR MORE PERSISTENT LOW CONDITIONS. CONDITIONS SHOULD GENERALLY BE MVFR WITH BRIEF PERIODS OF IFR OVERNIGHT...BUT PERIODS OF VFR ARE ALSO LIKELY. ARRIVAL OF DRIER AIR AND MORE ANTICYCLONIC FLOW LATE MORNING THRU THE AFTN WILL RESULT IN PREVAILING MVFR AT ALL TERMINALS BY AFTN. SOME PERIODS OF VFR ARE ALSO POSSIBLE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 517 AM EST WED NOV 27 2013 GALES ACROSS THE ERN HALF OF LAKE SUPERIOR WILL DIMINISH BY THIS AFTERNOON AS THE SFC RIDGE FROM NW ONTARIO INTO MN BUILDS TO THE EAST AND PRES GRADIENT WEAKENS. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...ARE EXPECTED SATURDAY OVER MAINLY ERN LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ005. LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR MIZ004-006. LAKE SUPERIOR... GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ265. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...VOSS LONG TERM...JLB AVIATION...ROLFSON MARINE...JLB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
632 AM CST WED NOV 27 2013 .UPDATE... ISSUED AT 632 AM CST WED NOV 27 2013 WITH STRATUS MOVING IN THIS AFTERNOON...ADDED ISOLD FLURRIES 21-00Z IN ADDITION TO WHAT WAS IN THE FORECAST AFTER 00Z. OTHERWISE...INHERITED FORECAST REMAINS VALID...THUS CHANGES WERE ONLY TO INCORPORATE LATEST OBS AND NEAR TERM MODEL GUIDANCE. SEE SHORT TERM DISCUSSION BELOW FOR DETAILS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CST WED NOV 27 2013 CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHWESTERN SASKATCHEWAN/NORTH CENTRAL MONTANA. SOUTH WINDS AHEAD OF THE SYSTEM HAD DEVELOPED OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENING HOURS...AND STRONG WARM ADVECTION CONTINUED OVER THE WESTERN HALF OF NORTH DAKOTA AHEAD OF THIS SYSTEM. REGARDING TEMPERATURES...READINGS HAD RISEN INTO THE LOWER 20S ACROSS FAR WESTERN NORTH DAKOTA...AND INTO THE TEENS OVER WESTERN PORTIONS OF CENTRAL NORTH DAKOTA. THIS TREND OF RISING TEMPERATURES SHOULD CONTINUE EASTWARD THROUGH SUNRISE. ALONG WITH THE WARM ADVECTION...IT APPEARS THAT THE RUC MODEL HAS A VERY GOOD HANDLE ON H850 TO H700 LIFTING OCCURRING OVER SOUTHEASTERN SASKATCHEWAN/SOUTHWEST MANITOBA/NORTHERN NORTH DAKOTA. THIS MODEL WAS DEPICTING LIGHT PRECIPITATION OVER THIS SAME AREA AROUND MIDNIGHT...AND IT CONTINUES/ADVECTS IT EASTWARD DURING THE REST OF THE NIGHTTIME HOURS. CURRENT RADAR LOOPS VALIDATING AT LEAST SOME ENHANCED CLOUDS AND/OR LIFT OCCURRING...SO WILL KEEP A MENTION OF FLURRIES FOR THIS TIME PERIOD OVER NORTH CENTRAL TO THE JAMESTOWN AREA THROUGH SUNRISE. THE 06Z NAM AS WELL AS THE 00Z ECMWF AND GFS MODELS ARE NOW DEPICTING LIGHT PRECIPITATION OVER NORTHEASTERN NORTH DAKOTA FROM 6 AM TO NOON TIME FRAME. THIS APPEARS TO BE THE RESULT OF BOTH WARM ADVECTION LIFTING AT H850/H700 AS WELL AS REINFORCEMENT FROM AN UPPER LEVEL SHORTWAVE MOVING SOUTHEAST OUT OF MANITOBA. ADDED A MENTION OF CHANCE OF LIGHT SNOW THIS MORNING IN THE BOTTINEAU/TURTLE MOUNTAIN/HARVEY AREA. CONTINUED WARM ADVECTION THROUGH THE DAY UNTIL A COLD FRONT DIVES SOUTHEAST OUT OF SASKATCHEWAN THIS AFTERNOON SWEEPING ACROSS THE STATE AND REACHING THE JAMES RIVER VALLEY LATE AFTERNOON/EVENING. SOUTH WINDS AHEAD OF THE FRONT WILL BECOME NORTHWEST AT AROUND 15 MPH. EXPECTING HIGH TEMPERATURES TO REACH INTO THE 20S OVER NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THROUGH THE JAMES RIVER VALLEY...WITH TEMPERATURES IN THE 30S MAINLY SOUTH AND WEST OF THE MISSOURI RIVER. THE FAR SOUTHWEST MAY SEE TEMPERATURES REACH INTO THE LOWER 40S. THE COLD FRONT WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH PRESSURE SYSTEM...AND EXPECTING LOWS TONIGHT FROM THE SINGLE DIGITS NORTH TO LOWER TEENS SOUTH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CST WED NOV 27 2013 FORECAST HIGHLIGHTS IN THE LONG TERM PERIOD WILL BY MAINLY DRY CONDITIONS THROUGH SATURDAY NIGHT...FOLLOWED BY A POSSIBLE VERY ACTIVE WEATHER PERIOD SOMETIME FROM SUNDAY INTO THE MIDDLE PORTIONS OF NEXT WEEK. THE EXTENDED PERIOD BEGINS THURSDAY MORNING WITH STRONG NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS AND A SFC RIDGE OF HIGH PRESSURE EXTENDING FROM NORTH OF MANITOBA SOUTH THROUGH THE DAKOTAS. BOTH THE 00Z NAM/GFS CONTINUE TO INDICATE LOW STRATUS FROM WEDNESDAY NIGHT PERSISTING INTO THURSDAY MORNING ACROSS MUCH OF WEST AND CENTRAL NORTH DAKOTA WITH THE SFC RIDGE. COUPLED WITH SUBTLE MID/UPPER LEVEL SUPPORT...OPTED TO CONTINUE THE ISOLATED FLURRY MENTION FROM WED NIGHT INTO MID MORNING THURSDAY. WILL SEE A PATTERN CHANGE STARTING ON FRIDAY AS UPPER LEVEL LOW PRESSURE OVER EASTERN CANADA THURSDAY LIFTS MORE NORTHEAST TOWARDS WESTERN GREENLAND FRI-SAT. THIS TRANSITIONS OUR FLOW ALOFT FROM STRONG NORTHWESTERLY TO A WEAKER NORTHWESTERLY BY SATURDAY...AND EVENTUALLY QUASI-ZONAL BY SUNDAY. WILL MAINTAIN DRY CONDITIONS AND A SLOW WARM-UP UNDER THIS FLOW PATTERN THROUGH SAT NIGHT. AS THIS CHANGE IS OCCURRING...STRONG UPPER LOW OVER ALASKA ON THURSDAY WILL MOVE SLOWLY SOUTHEAST ALONG THE CANADIAN PACIFIC SHORE SATURDAY NIGHT INTO SUNDAY...THEN INTO THE PACIFIC NORTHWEST BY EARLY MONDAY. LEAD EMBEDDED IMPULSES WITHIN THIS FEATURE MAY BRING PRECIPITATION TO THE DAKOTAS AS EARLY AS SUNDAY DAYTIME (00Z ECMWF)...OR MAY HOLD OFF UNTIL MONDAY (00Z GFS). THUS MODELS STILL SHOWING LOTS OF UNCERTAINTY ONLY 4-5 DAYS OUT. WAA AHEAD OF THIS SYSTEM WOULD SUPPORT A VARIETY OF PRECIPITATION TYPES...DEPENDING WHETHER WE SEE PRECIP AT NIGHT OR IN THE DAYTIME. UNCERTAINTY COMPOUNDS AS WE GO FORWARD INTO THE EARLY TO MIDDLE PORTIONS OF NEXT WEEK AS THE UPPER LOW EVOLVES. THE LATEST GFS PRODUCES SPLIT FLOW DEVELOPING MONDAY NIGHT INTO TUESDAY...WITH THE BULK OF ASSOCIATED PRECIPITATION OFF TO OUR NORTH IN CANADA. THE LATEST 00Z ECMWF (MUCH SLOWER THAN THE 12Z ECMWF) MAINTAINS A CLOSED SYSTEM AND DOES IMPACT WEST AND NORTH CENTRAL PARTS OF THE STATE WITH WINTER WEATHER. ALL SOLUTIONS BRING IN MUCH COLDER AIR SOMETIME TUESDAY OR WEDNESDAY. WILL CONTINUE TO MONITOR IN THE COMING DAYS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 632 AM CST WED NOV 27 2013 VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. A WARM FRONT WILL MOVE EAST ACROSS THE STATE TODAY. THIS WILL BE FOLLOWED BY A COLD FRONT THAT WILL MOVE SOUTHEAST ACROSS THE STATE. SOUTH WINDS WITH SCT-BKN MID AND HIGH CLOUDS AHEAD OF THE WARM FRONT...FOLLOWED BY SOUTHWEST WINDS FOR A BRIEF PERIOD...THEN A NORTHWESTERLY WIND SHIFT WITH THE COLD FRONT. MVFR CIGS NORTH AND WEST (KISN-KMOT-KDIK) AFTER 18Z AND REACHING KBIS WEDNESDAY MID-AFTERNOON. LOW CONFIDENCE IN TIMING OF MVFR CIGS REACHING TAF SITES AFTER WINDS SHIFT TO NORTHWEST. WIND SHIFT AND MVFR CIGS NOT EXPECTED TO REACH KJMS UNTIL LATE AFTERNOON OR EVENING. MVFR CIGS EXPECTED TO PERSIST BEYOND THE END OF THE TAF PERIOD (12Z THU). && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...JV LONG TERM...NH AVIATION...JV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
930 AM EST WED NOV 27 2013 .SYNOPSIS... WINTER STORM SYSTEM LIFTS TO THE NORTHEAST. UPSLOPE SNOW TODAY AND TONIGHT. HIGH PRESSURE BUILDING IN ON THANKSGIVING DAY AND LINGERING FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... BULK OF PRECIPITATION STARTING TO SHIFT EASTWARD ACROSS THE CWA ALONG WITH WEAK BOUNDARY. EXPECTING A TRANSITION TO NORTHWEST UPSLOPE SNOW SHOWERS LATER THIS MORNING INTO EARLY AFTERNOON. COULD SEE ANOTHER INCH OR SO ACROSS PARTS OF THE WV LOWLANDS THIS AFTERNOON/EVENING PARTICULARLY IF A DECENT BAND IS ABLE TO SET UP ACROSS THE LAKES...WITH STILL SEVERAL INCHES POSSIBLE ACROSS THE HIGHER TERRAIN COUNTIES...PARTICULARLY ON WEST/NORTHWEST FACING SLOPES. FOR NOW...WILL LEAVE HEADLINES AS IS...SOME OF THE LOWLAND COUNTIES MAY BE ABLE TO BE CANCELLED EARLY...BUT WILL MONITOR FOR NOW. PREVIOUS DISCUSSION... GENERALLY FOLLOWING THE HRRR MODEL IN REGARDS TO THE EVOLUTION OF THE SYNOPTIC SNOW OVER THE NEXT FEW HOURS INTO THE DAWN HOURS. DEFORMATION ZONE PROVIDING THE MAIN FORCING OF THE SNOW AT THIS POINT WILL DRIFT TO THE EAST THROUGH 12Z TODAY...AND CARRY THE BETTER CHANCES FOR SNOW WITH IT. THERE WAS A PATCH OF DRIER AIR TO CONTEND WITH A FEW HOURS AGO DURING THE TEMPERATURE TRANSITION TO BELOW FREEZING VALUES...AND HAVE GOTTEN OFF TO A SLOW START IN TERMS OF ACCUMULATIONS. THIS SPARKS A FEW CONCERNS ABOUT MEETING THE PREVIOUSLY FORECASTED AMOUNTS...BUT WILL NOT GIVE UP ON IT JUST YET AS WE STILL HAVE A FEW HOURS TO GET SOME ACCUMULATIONS OUT OF THIS. AS THE MAIN SYNOPTIC FORCING FOR THIS EVENT DEPARTS WITH THE DEFORMATION ZONES PUSHING EAST OF THE MOUNTAINS AND THE 500MB TROUGH AXIS PASSING LATER TODAY...THE SET UP LOOKS FAIRLY DECENT TO HAVE CONVECTIVE SNOW FOR THE FIRST PART OF TODAY. LOOKING AT A CROSS SECTION ORIENTED TO THE MEAN LOW LEVEL WIND SHOWS GOOD SATURATION INTO THE CRYSTAL GROWTH LAYER...FED BY NORTHWEST FLOW THROUGH THE LOW LEVELS. FIGURE THE NATURE OF THE SNOW WILL BE OFF AND ON AT THIS POINT...BUT A QUICK INCH HERE AND THERE WILL BE POSSIBLE THROUGH 18Z OR 20Z TODAY FOR THE LOWLANDS. THIS POTENTIAL INCREASED IN THE MOUNTAINS IN THE BETTER UPSLOPE CONDITIONS. AFTER THAT...IT WILL MAINLY BE A MOUNTAIN EVENT ONLY THAT WILL SLOWLY FADE DURING THE OVERNIGHT PERIOD. WINDS WILL BE ON THE INCREASE OUT OF THE NORTHWEST TODAY...WITH GUSTS UP TO 30KTS AT TIMES. BLOWING SNOW OVER THE HIGHEST RIDGES IS LIKELY LATER TODAY AND TONIGHT. DID NOT GET CUTE WITH THE TEMPERATURES TODAY. MAX TEMPERATURES MAY BE RIGHT AT DAWN AS THE COLDER AIR COMES IN...AND THEN WILL CHILL A COUPLE DEGREES...BUT COULD MAKE A DEGREE OR TWO RECOVERY THROUGH THE AFTERNOON TOWARDS THE MORNING VALUES. IN THE END...HIGHS AROUND 30F WILL RULE FOR MUCH OF THE AREA...AND GETTING COLDER FOR THE MOUNTAINS BY EVENING. OVERNIGHT...HAVE SNOWSHOE IN THE SINGLE DIGITS...WITH OTHER LOCATIONS FALLING INTO THE TEENS TO LOWER 20S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... UPPER PATTERN ACROSS THE UNITED STATES RETURNS TO A ZONAL FLOW THROUGH THE EARLY WEEKEND. THIS WILL KEEP THE COLDEST AIR WITH CANADIAN HIGH PRESSURE CENTERS UP IN CANADA. EVEN THOUGH UPPER IMPULSES WILL TRACK EASTWARD THROUGH THE FLOW...THEY WILL BE WEAK. THIS..IN COMBINATION WITH GULF OF MEXICO MOISTURE BEING CONFINED ACROSS THE SOUTHERN STATES...WILL BRING DRY CONDITIONS AND A DAY TIME WARMING TREND. HIGH TEMPERATURES IN THE 30S THURSDAY WILL REACH WELL INTO THE 40S FRIDAY AND SATURDAY. HOWEVER...THE DRY AIR ALONG WITH LACK OF CLOUDS...WILL ALLOW FOR COLD NIGHT TIME READINGS WELL BELOW FREEZING. THUS...LOOK FOR DRY WEATHER AND A LARGE RANGE IN DIURNAL TEMPERATURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... A RATHER TRANQUIL ZONAL FLOW WITH SOME WEAK TROUGH APPROACHING LATE IN THE WEEKEND. WILL CONTINUE BRINGING BACK SOME CHANCE POPS FOR LIGHT RAIN SUNDAY NIGHT AND BECOMING MORE WIDESPREAD MONDAY BEFORE DIMINISHING POPS MONDAY NIGHT. NOT ANY STRONG FEATURES OR FRONTS EXPECTED DURING THIS PERIOD. NO BIG DEVIATIONS FROM HPC MEDIUM RANGE GROUP TEMPERATURES. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... IFR FOR TERMINALS SOUTH AND EAST OF THE OHIO RIVER...SO EXPECT PKB TO COME UP TO MVFR IN THE NEXT COUPLE OF HOURS FOR A SHORT PERIOD OF TIME. HTS IS ALREADY THERE. AS THE BAND OF SNOW OVER THE WEST VIRGINIA LOWLANDS SLOWLY RETREATS TO THE EAST...COULD GET SOME BRIEF MVFR AND IFR IN THE TRANSITION TO UPSLOPE SNOW IN NORTHWEST FLOW. WILL BE IN AND OUT OF SNOW SHOWERS FOR THE BULK OF THE DAY...WITH MORE PERSISTENT SNOW FOR CKB...EKN..AND BKW. OBSERVATIONS ARE EXPECTED TO BOUNCE...SO TEMPO GROUPS ARE THE TICKET TODAY FOR THE OSCILLATING CONDITIONS. WINDS TURN NORTHWESTERLY THIS MORNING...AND WILL INCREASE THROUGH THE DAY. BY AFTERNOON HOURS...GUSTS 25-30KTS ARE NOT OUT OF THE QUESTION...AND MAY SEE 35KTS OVER THE HIGHEST RIDGES. WINDS FALL BACK DOWN TO THE 10-15KTS BY 12Z THURSDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: VISIBILITY RESTRICTIONS COULD VARY WITH SNOW. CEILINGS WILL DROP SLIGHTLY IN HEAVIER SNOW. 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 14 15 16 17 18 19 20 21 22 23 00 01 EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 CRW CONSISTENCY M H L L L L L L M L L L HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY L L L L L L L L L L L L EKN CONSISTENCY M M M L L L L L L L L L PKB CONSISTENCY L H L L L H M L L L L L CKB CONSISTENCY H H H L L L L L L L L L AFTER 12Z THURSDAY... NO WIDESPREAD IFR EXPECTED AFTER 12Z THURSDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR WVZ035>037. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ008>011-013>020-024>034-039-040. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR WVZ038-046- 047. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR WVZ005>007. OH...NONE. KY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR KYZ105. VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...SL/26 SHORT TERM...JMV LONG TERM...KTB AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
541 AM EST WED NOV 27 2013 .SYNOPSIS... WINTER STORM SYSTEM LIFTS TO THE NORTHEAST. UPSLOPE SNOW TODAY AND TONIGHT. HIGH PRESSURE BUILDING IN ON THANKSGIVING DAY AND LINGERING FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... DEFORMATION ZONE HAS SET UP OVER THE WEST VIRGINIA LOWLANDS AND HAS LITTLE EASTWARD MOTION TO IT. THIS MAY PROLONG THE DURATION OF THE SYNOPTIC SNOW JUST A BIT FOR THE KANAWHA VALLEY AND I-79 CORRIDOR AND CONTRIBUTE TO MORE ACCUMULATION BEFORE THE TRANSITION TO NORTHWEST FLOW SNOWFALL. PREVIOUS DISCUSSION... GENERALLY FOLLOWING THE HRRR MODEL IN REGARDS TO THE EVOLUTION OF THE SYNOPTIC SNOW OVER THE NEXT FEW HOURS INTO THE DAWN HOURS. DEFORMATION ZONE PROVIDING THE MAIN FORCING OF THE SNOW AT THIS POINT WILL DRIFT TO THE EAST THROUGH 12Z TODAY...AND CARRY THE BETTER CHANCES FOR SNOW WITH IT. THERE WAS A PATCH OF DRIER AIR TO CONTEND WITH A FEW HOURS AGO DURING THE TEMPERATURE TRANSITION TO BELOW FREEZING VALUES...AND HAVE GOTTEN OFF TO A SLOW START IN TERMS OF ACCUMULATIONS. THIS SPARKS A FEW CONCERNS ABOUT MEETING THE PREVIOUSLY FORECASTED AMOUNTS...BUT WILL NOT GIVE UP ON IT JUST YET AS WE STILL HAVE A FEW HOURS TO GET SOME ACCUMULATIONS OUT OF THIS. AS THE MAIN SYNOPTIC FORCING FOR THIS EVENT DEPARTS WITH THE DEFORMATION ZONES PUSHING EAST OF THE MOUNTAINS AND THE 500MB TROUGH AXIS PASSING LATER TODAY...THE SET UP LOOKS FAIRLY DECENT TO HAVE CONVECTIVE SNOW FOR THE FIRST PART OF TODAY. LOOKING AT A CROSS SECTION ORIENTED TO THE MEAN LOW LEVEL WIND SHOWS GOOD SATURATION INTO THE CRYSTAL GROWTH LAYER...FED BY NORTHWEST FLOW THROUGH THE LOW LEVELS. FIGURE THE NATURE OF THE SNOW WILL BE OFF AND ON AT THIS POINT...BUT A QUICK INCH HERE AND THERE WILL BE POSSIBLE THROUGH 18Z OR 20Z TODAY FOR THE LOWLANDS. THIS POTENTIAL INCREASED IN THE MOUNTAINS IN THE BETTER UPSLOPE CONDITIONS. AFTER THAT...IT WILL MAINLY BE A MOUNTAIN EVENT ONLY THAT WILL SLOWLY FADE DURING THE OVERNIGHT PERIOD. WINDS WILL BE ON THE INCREASE OUT OF THE NORTHWEST TODAY...WITH GUSTS UP TO 30KTS AT TIMES. BLOWING SNOW OVER THE HIGHEST RIDGES IS LIKELY LATER TODAY AND TONIGHT. DID NOT GET CUTE WITH THE TEMPERATURES TODAY. MAX TEMPERATURES MAY BE RIGHT AT DAWN AS THE COLDER AIR COMES IN...AND THEN WILL CHILL A COUPLE DEGREES...BUT COULD MAKE A DEGREE OR TWO RECOVERY THROUGH THE AFTERNOON TOWARDS THE MORNING VALUES. IN THE END...HIGHS AROUND 30F WILL RULE FOR MUCH OF THE AREA...AND GETTING COLDER FOR THE MOUNTAINS BY EVENING. OVERNIGHT...HAVE SNOWSHOE IN THE SINGLE DIGITS...WITH OTHER LOCATIONS FALLING INTO THE TEENS TO LOWER 20S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... UPPER PATTERN ACROSS THE UNITED STATES RETURNS TO A ZONAL FLOW THROUGH THE EARLY WEEKEND. THIS WILL KEEP THE COLDEST AIR WITH CANADIAN HIGH PRESSURE CENTERS UP IN CANADA. EVEN THOUGH UPPER IMPULSES WILL TRACK EASTWARD THROUGH THE FLOW...THEY WILL BE WEAK. THIS..IN COMBINATION WITH GULF OF MEXICO MOISTURE BEING CONFINED ACROSS THE SOUTHERN STATES...WILL BRING DRY CONDITIONS AND A DAY TIME WARMING TREND. HIGH TEMPERATURES IN THE 30S THURSDAY WILL REACH WELL INTO THE 40S FRIDAY AND SATURDAY. HOWEVER...THE DRY AIR ALONG WITH LACK OF CLOUDS...WILL ALLOW FOR COLD NIGHT TIME READINGS WELL BELOW FREEZING. THUS...LOOK FOR DRY WEATHER AND A LARGE RANGE IN DIURNAL TEMPERATURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... A RATHER TRANQUIL ZONAL FLOW WITH SOME WEAK TROUGH APPROACHING LATE IN THE WEEKEND. WILL CONTINUE BRINGING BACK SOME CHANCE POPS FOR LIGHT RAIN SUNDAY NIGHT AND BECOMING MORE WIDESPREAD MONDAY BEFORE DIMINISHING POPS MONDAY NIGHT. NOT ANY STRONG FEATURES OR FRONTS EXPECTED DURING THIS PERIOD. NO BIG DEVIATIONS FROM HPC MEDIUM RANGE GROUP TEMPERATURES. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... IFR FOR TERMINALS SOUTH AND EAST OF THE OHIO RIVER...SO EXPECT PKB TO COME UP TO MVFR IN THE NEXT COUPLE OF HOURS FOR A SHORT PERIOD OF TIME. HTS IS ALREADY THERE. AS THE BAND OF SNOW OVER THE WEST VIRGINIA LOWLANDS SLOWLY RETREATS TO THE EAST...COULD GET SOME BRIEF MVFR AND IFR IN THE TRANSITION TO UPSLOPE SNOW IN NORTHWEST FLOW. WILL BE IN AND OUT OF SNOW SHOWERS FOR THE BULK OF THE DAY...WITH MORE PERSISTENT SNOW FOR CKB...EKN..AND BKW. OBSERVATIONS ARE EXPECTED TO BOUNCE...SO TEMPO GROUPS ARE THE TICKET TODAY FOR THE OSCILLATING CONDITIONS. WINDS TURN NORTHWESTERLY THIS MORNING...AND WILL INCREASE THROUGH THE DAY. BY AFTERNOON HOURS...GUSTS 25-30KTS ARE NOT OUT OF THE QUESTION...AND MAY SEE 35KTS OVER THE HIGHEST RIDGES. WINDS FALL BACK DOWN TO THE 10-15KTS BY 12Z THURSDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: VISIBILITY RESTRICTIONS COULD VARY WITH SNOW. CEILINGS WILL DROP SLIGHTLY IN HEAVIER SNOW. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY M H H H M L L L L L L M HTS CONSISTENCY H H L M H H H M H H H H BKW CONSISTENCY H H L L L L L L L L L L EKN CONSISTENCY M M M M M M L L L L L L PKB CONSISTENCY H H H L H L L L H M L L CKB CONSISTENCY M M M H H M L L L L L L AFTER 12Z THURSDAY... NO WIDESPREAD IFR EXPECTED AFTER 12Z THURSDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR WVZ035>037. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ008>011-013>020-024>034-039-040. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR WVZ038-046- 047. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR WVZ005>007. OH...NONE. KY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR KYZ105. VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...26 SHORT TERM...JMV LONG TERM...KTB AVIATION...26
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
857 AM CST WED NOV 27 2013 .UPDATE... SNOW FALLING IN EASTERN AREAS OF MID STATE WITH SOME ACCUMULATION ALONG THE PLATEAU. HAVE UPDATED GRIDS AND ZONES TO INCLUDE UP TO AN INCH OF SNOW MAINLY UPPER CUMBERLAND AREAS WITH AROUND HALF INCH WEST OF PLATEAU AS FAR BACK AS MACON...SMITH AND MAYBE DEKALB. 700 MBAR TROUGH AXIS NORTH TO SOUTH JUST EAST OF INTERSTATE 65 WITH A SHOT OF WARM ADVECTION AT 850 MBAR SHOWING UP IN RUC NOSING IN ACROSS NORTHEAST MIDDLE TENNESSEE INTO UPPER CUMBERLAND. WITH THIS SETUP THINK UPPER CUMBERLAND WILL SEE AT LEAST 1 INCH OF ACCUMULATION AND MAYBE A LITTLE MORE BEFORE ENDING. WILL HOLD OFF ON ADVISORY FOR NOW BUT NOT SURE HOW LONG I CAN. BOYD && .PREV DISCUSSION... /ISSUED 532 AM CST WED NOV 27 2013/ UPDATE...FOR AVIATION. AVIATION... BNA AND CKV 12Z TAFS...VFR WX IS EXPECTED TODAY WITH GUSTY NNW WINDS TO 25KT AT TIMES. BKN STRATO CU WILL BECOME SKC THROUGH THE DAY. FOR TONIGHT...WINDS WILL BECOME LIGHT NW WITH SKC UNDER COLD HIGH PRESSURE. CSV...MVFR CIGS WILL PERSIST THROUGH 18Z...THEN IMPROVE IN THE AFTERNOON. GUSTY NNW WINDS TO 25KT EARLY TODAY WILL BECOME LIGHT BY 28/00Z. 13 PREV DISCUSSION... /ISSUED 412 AM CST WED NOV 27 2013/ DISCUSSION... FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED. FORECAST QUANDARIES...TEMPS...WX PATTERN FIRST PART OF NEXT WEEK. JUST WENT AHEAD AND ISSUED THE SUITE OF FORECAST PRODUCTS FOR TODAY AS THE POTENTIAL FOR ACCUMULATING SNOWFALL HAS ENDED ACROSS THE UPPER CUMBERLAND REGION...WITH POSSIBLY SOME ISO FLURRIES THRU THE MID MORNING HRS. OTHERWISE...BUILDING SFC RIDGING INFLUENCES WILL BE THE MAJOR WX PLAYER THRU THE REST OF THE WEEK AND INTO AT LEAST THE FIRST PART OF THE WEEKEND. A STRONG SFC PRESSURE GRADIENT HAS BEEN ESTABLISHED ACROSS THE MID STATE THIS MORNING WITH NWLY SUSTAINED WINDS GENERALLY 10 TO 20 MPH WITH SOME GUST APPROACHING 30 MPH. BELIEVE THAT ON WHOLE THIS TYPE OF RANGE OF WIND SPEEDS EXPECTED AT LEAST THRU THE EARLY AFTERNOON HRS TODAY UNTIL SFC RIDGING INFLUENCES BUILD CLOSER. ALSO EXPECTING DECREASING CLOUDINESS W TO E AS THE DAY PROGRESSES WITH DRY NW FLOW PATTERN ALOFT CONTINUING AT LEAST THRU TONIGHT AFTER THIS MORNING EXPECTED UPPER LEVEL TROUGH PASSAGE. THIS BUILDING HIGH PRESSURE SYSTEM WILL USHER AN ADDITIONAL SHOT OF COLD AIR TO THE MID STATE...WITH HIGHS TODAY IN RANGE OF CURRENT 10Z VALUES.. I.E. MAINLY IN THE LOWER 30S. A DEGREE OR TWO DIFFERENCES HERE OR THERE BETWEEN 00Z NAM/GFS/EURO MOS WITH A GENERAL LEAN TOWARD THE MORE MIDDLE OF THE ROAD GFS MOS VALUES FOR EXPECTED HIGH TEMPS FOR TODAY TAKEN. AS OF THIS TIME...ACTUALLY FORECASTING A HIGH FOR NASHVILLE OF 33 DEGREES... A COUPLE OF DEGREES WARMER THAN THE RECORD LOW MIN HIGH OF 31 DEGREES SET FOR THIS DATE IN 1938. HOWEVER...WITH THE ABOVE WINDS SPEEDS EXPECTED... WIND CHILL VALUES WILL GENERALLY AVERAGE IN THE UPPER TEENS DURING THE DAY ACROSS THE MID STATE. WITH WINDS GENERALLY BECOMING LIGHT...LOWS TONIGHT ARE EXPECTED TO MAINLY BE IN THE MID TO UPPER TEENS. EXPECTING A GENERALLY WARMING TREND TOWARD MORE SEASONAL VALUES WITH DRY CONDITIONS DUE TO SFC RIDGING INFLUENCES WITH UPPER LEVEL FLOW BECOMING MORE ZONALLY ALIGNED ALLOWING FOR SOME PASSING MID TO UPPER LEVEL CLOUDINESS...BUT GENERALLY MOCLR SKIES EXPECTED...FOR THE REST OF THE WEEK AND INTO AT LEAST THE FIRST PART OF THE WEEKEND. HIGHS ON THANKSGIVING DAY SHOULD GENERALLY BE IN LOWER 40S...WITH LOWS THURSDAY NIGHT MAINLY IN THE LOWER 20S. HIGHS ON FRI ARE EXPECTED TO BE AROUND 50 DEGREES WITH LOWS FRI NIGHT GENERALLY IN THE MID TO UPPER 20S. HIGHS ON SAT WILL GET EVEN CLOSER TO SEASONABLE NORMAL VALUES WITH HIGHS MAINLY IN THE LOWER 50S AND LOWS SAT NIGHT BACK CLOSE TO SEASONABLE NORMAL VALUES MAINLY IN THE LOWER 30S. LOOKS LIKE THE NEXT BEST CHANCE OF RAINFALL WILL BE ON SUN AS A WEAK SFC FRONT MOVES CLOSER TO THE MID STATE. SOME TIMING DIFFERENCES IN MODELS FOR THE FIRST PART OF NEXT WEEK...BUT GENERALLY EXPECTING WEAK DISTURBANCES IN UPPER LEVEL FLOW ALOFT...ALONG WITH A MORE PRONOUNCED UPPER LEVEL TROUGH PASSAGE BY LATE ON MON...ALONG ALSO WITH SLY SFC FLOW...TO ALL COMBINE TO GIVE US A CHANCE OF RAIN SUN NIGHT INTO MON...WITH TEMPS NEAR SEASONABLE NORMS. RIDGING INFLUENCES SHOULD AGAIN BUILD ACROSS THE MID STATE BY THE MID PORTION OF NEXT WEEK ALSO. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
320 PM EST WED NOV 27 2013 ...CHILLY TEMPERATURES TONIGHT THROUGH EARLY THURSDAY MORNING... .SYNOPSIS... 20Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A HIGHLY AMPLIFIED UPPER LEVEL PATTERN IN PLACE OVER THE CONUS...HIGHLIGHTED BY LONGWAVE RIDGING OVER THE INTER-MOUNTAIN WEST AND A DEEP/SHARP LONGWAVE TROUGH OVER THE EASTERN HALF OF THE NATION. THE TROUGH AXIS EXTENDS FROM THE EASTERN GREAT LAKES TO THE SOUTHEAST COAST. THE STRONG SOUTHERN STREAM IMPULSE WHICH BROUGHT THE SHOWERS AND STORMS TO THE AREA LAST NIGHT IS NOW QUICKLY PIVOTING AWAY FROM OUR REGION UP THE EASTERN SEABOARD. WV IMAGERY SHOWS A BROAD EXPANSE OF IMPRESSIVE SUBSIDENCE/DRYING IN THE MID/UPPER LEVELS BEHIND THIS SHORTWAVE COVERING THE ENTIRE PENINSULA. AT THE SURFACE...COLD FRONT HAS PASSED WELL OFF TO THE EAST OF THE PENINSULA WITH GUSTY NORTHWEST WINDS IN ITS WAKE. DEWPOINTS HAVE BECOME MUCH MORE COMFORTABLE...DROPPING INTO THE MIDDLE 40S NORTH AND MIDDLE 50S SOUTH. EXPECT THESE VALUES TO CONTINUE TO DROP THROUGH THE EVENING HOURS. A LONG CAA FETCH OVER THE RELATIVELY WARM GULF WATERS IS PRODUCING SCT-BKN STRATOCU WITHING THE NW FLOW. PERIODS OF THESE SCT-BKN CLOUDS SHOULD CONTINUE TO ROLL ASHORE UNTIL THE WINDS VEER AROUND MORE TO THE NORTH LATER THIS EVENING. TEMPERATURES HAVE REACHED THEIR MAXIMUMS FOR THE DAY AND ARE NOW BEGINNING TO FALL WITH THE CONTINUED CAA AND LESSENING SUN ANGLE. THIS EVENING WILL BECOME CHILLY QUICKLY WITH THE SETTING OF THE SUN. && .SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)... THE COLDEST NIGHT OF THE SEASON SO FAR IN STORE FOR MANY LOCATIONS. THE FREEZE WATCH HAS BEEN UPGRADED TO A FREEZE WARNING FOR CITRUS AND LEVY COUNTY FOR LATE TONIGHT AND EARLY THURSDAY MORNING. MUCH OF LEVY COUNTY IS EXPECTED TO DROP BELOW FREEZING FOR A FEW HOURS AWAY FROM THE IMMEDIATE COAST WITH MAINLY NORTHERN INLAND AREAS OF CITRUS COUNTY. THE FREEZE WATCH WAS CANCELLED FOR SUMTER AND HERNANDO COUNTIES AS TEMPERATURES ARE NO LONGER EXPECTED TO REACH THE FREEZING POINT FOR 2 OR MORE HOURS. HOWEVER...NORMALLY COLDER AND SHELTERED LOCATIONS WITHIN SUMTER AND HERNANDO COUNTIES MAY STILL BRIEFLY TOUCH FREEZING AROUND SUNRISE. EVEN OUTSIDE OF THESE MORE NORTHERN ZONES...TEMPERATURES WILL BECOME QUITE CHILLY BY SUNRISE WITH WIDESPREAD MID 30S TO LOWER 40S. TEMPERATURES ALONG THE IMMEDIATE COAST FROM PINELLAS COUNTY SOUTHWARD SHOULD REMAIN IN THE 40S WITH MORE INFLUENCE FROM THE WATER. THESE LOW TEMPERATURES REGION-WIDE REPRESENT A 25-30 DEGREE DECREASE FROM THE LOW TEMPERATURES ON WEDNESDAY MORNING. WINDS WILL DIMINISH FROM THE GUSTY NATURE THIS AFTERNOON...BUT WITH THE HIGH WELL TO OUR NORTH...DO NOT ANTICIPATE A DECOUPLING OF THE BOUNDARY LAYER AND WINDS GOING CALM. THEREFORE AT LEAST SOME MOMENTUM WILL PUSH WIND CHILLS AROUND SUNRISE DOWN INTO THE LOWER/MID 30S FOR ALL BUT THE FAR SOUTHERN ZONES. FROM HERNANDO/SUMTER COUNTY NORTHWARD...WIND CHILLS ARE FORECAST TO BRIEFLY DROP INTO THE 20S. SO EITHER WAY...IT WILL BE CHILLY MORNING FOR ANYONE WITH OUTDOOR ACTIVITIES WITHIN A FEW HOURS EITHER SIDE OF SUNRISE. THANKSGIVING DAY / NIGHT... A PLEASANT/FAIR DAY IN STORE AFTER THE CHILLY START. A DEEP DRY ATMOSPHERIC COLUMN WITHIN ZONAL FLOW ALOFT WILL KEEP OUR FORECAST RAIN FREE WITH A NORTHEAST WIND SOUTH OF A RIDGE AXIS OVER THE CAROLINAS. THIS NORTHEAST FLOW WILL BRING SOME LOW LEVEL MOISTURE IN FROM THE ATLANTIC BY THE AFTERNOON. THEREFORE LOOKING FOR MOSTLY SUNNY SKIES IN THE MORNING AND THEN A MIX OF SUN AND CLOUDS UNDER A SCT CU FIELD FOR THE AFTERNOON. HIGH TEMPERATURES WILL RECOVER FROM THE COOL MORNING TO AROUND 60 FOR LEVY COUNTY...RANGING TO THE MIDDLE/UPPER 60S ALONG THE I-4 CORRIDOR AND AROUND 70 DOWN TOWARD FT MYERS. THURSDAY NIGHT WILL BE ANOTHER COOL NIGHT...BUT DO NOT ANTICIPATE ANY FREEZE CONCERNS. LOW TEMPS WILL RANGE FROM THE MID/UPPER 30S OVER LEVY COUNTY TO THE MID/UPPER 40S FOR MOST OTHER LOCATIONS. PORTIONS OF SOUTHERN PINELLAS AND COASTAL AREA AROUND CHARLOTTE COUNTY WILL ALSO BE WARMER. FRIDAY/FRIDAY NIGHT... ANOTHER FAIR...PLEASANT...AND DRY DAY ON TAP WITH A WARMING TREND BEGINNING. HIGH TEMPERATURES RECOVER TO THE LOWER 70S NORTH...TO MID 70S ALONG THE I-4 CORRIDOR...AND UPPER 70S FURTHER SOUTH. LOW TEMPERATURES FRIDAY NIGHT STAYING IN THE 50S FOR ALL AREAS EXPECT THE FAR NORTHERN NATURE COAST ZONES. SAFE TRAVELS FOR THE REST OF THE AFTERNOON AND EARLY EVENING ON THIS BUSIEST TRAVEL DAY OF THE YEAR. THOSE TRAVELING ON THE I-4 AND FLORIDA I-75 CORRIDORS THE REMAINDER OF THE DAY CAN EXPECT DRY CONDITIONS...BUT RATHER GUSTY WINDS OUT OF THE NORTHWEST. WINDS SHOULD BECOME LESS GUSTY THROUGH THE EVENING HOURS. && .LONG TERM (SATURDAY - NEXT TUESDAY)... MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE LONG TERM PERIOD. HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE OVER THE WEEKEND WITH RAIN FREE CONDITIONS EXPECTED. MODEL SOLUTIONS THEN SHOW A WAVE OF LOW PRESSURE TRACKING ACROSS THE STATE IN THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME FRAME. THERE ARE SOME DIFFERENCES IN STRENGTH AND TIMING OF THIS WAVE OF LOW PRESSURE...SO WON/T TRY TO PIN DOWN THE EXACT DETAILS AT THIS TIME...AND WILL CARRY SLIGHT CHANCE/LOW CHANCE POPS. HIGH PRESSURE THEN BUILDS BACK IN BEHIND THE EXITING WAVE THROUGH THE MIDDLE OF NEXT WEEK...SO WILL KEEP THE FORECAST FREE FROM RAIN. TEMPERATURES THROUGH THE LONG TERM PERIODS WILL RUN NEAR TO SLIGHTLY ABOVE NORMAL. && .AVIATION... BKN MAINLY VFR CIGS...BUT OCNL MVFR...THROUGH THE AFTERNOON. SCT THIS EVENING THEN SKC THROUGH THU MORNING. GUSTY W-NW WINDS DIMINISH IN THE EVENING AND VEER TO NORTHERLY. && .MARINE... SMALL CRAFT ADVISORIES REMAIN IN EFFECT THROUGH THURSDAY MORNING. STRONG NORTHWEST WINDS IN THE WAKE OF A COLD FRONT ARE AT HIGH END ADVISORY CRITERIA. WAVE HEIGHTS HAVE ALSO INCREASE TO BETWEEN 9-11 FEET OFFSHORE. WINDS WILL SHIFT NORTH OVERNIGHT AND THEN NORTHEAST ON THURSDAY MORNING WITH SOME IMPROVEMENT IN CONDITIONS THROUGH THE DAY...ALTHOUGH PERIODS OF CAUTIONARY LEVEL WINDS ARE LIKELY TO LINGER THROUGH THE END OF THE WEEK. && .FIRE WEATHER... HIGH PRESSURE SETTLES IN OVER THE GULF COAST TONIGHT WITH A COOL TO COLD DRY NORTHERLY FLOW. THE HIGH CONTINUES THURSDAY AND PROVIDES ROBUST TRANSPORT WINDS THE RESULT IN SOME HIGH DISPERSION INDICES...ESPECIALLY INLAND...ALONG WITH AFTERNOON RELATIVE HUMIDITY VALUES THAT APPROACH BUT DO NOT REACH CRITICAL LEVELS. THE HIGH MOVES EASTWARD THROUGH THE WEEKEND WITH BOTH TEMPERATURES AND HUMIDITY MODERATING AS THE LOW LEVEL FLOW BECOMES NORTHEASTERLY. A WEAK WAVE OF LOWER PRESSURE TRACKS ACROSS FLORIDA MONDAY WITH A SLIGHT CHANCE TO A CHANCE OF SHOWERS. && .PRELIMINARY POINT TEMPS/POPS... TPA 38 66 51 74 / 0 0 0 10 FMY 44 71 55 79 / 0 0 10 10 GIF 39 68 49 74 / 0 0 10 10 SRQ 42 69 52 76 / 0 0 0 10 BKV 32 65 44 73 / 0 0 0 10 SPG 46 66 56 73 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...LAKE WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS- HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-PINELLAS-POLK- SARASOTA-SUMTER. FREEZE WARNING FROM 3 AM TO 9 AM EST THURSDAY FOR CITRUS- LEVY. RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. HIGH SURF ADVISORY UNTIL 7 AM EST THURSDAY FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR TAMPA BAY WATERS. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WEATHER...RUDE LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1249 PM EST WED NOV 27 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 326 AM EST WED NOV 27 2013 LAKE EFFECT SNOW SHOWERS WILL CONTINUE TODAY MAINLY WEST OF U.S. 131. ADDITIONAL ACCUMULATIONS OF ONE TO FOUR INCHES CAN BE EXPECTED BEFORE THE PRECIPITATION DWINDLES THIS EVENING. MEANWHILE AREAS EAST OF U.S. 131 WILL SEE LITTLE TO NO ACCUMULATION. AFTER A QUIET PERIOD TONIGHT...ANOTHER CLIPPER SYSTEM WILL BRING ANOTHER ROUND OF SNOW TO ALL OF SOUTHWEST MICHIGAN STARTING TOWARD DAYBREAK THANKSGIVING DAY. THE SNOW WILL BE ENHANCED BY LAKE MICHIGAN AND PORTIONS OF WEST CENTRAL LOWER MICHIGAN SHOULD SEE THREE TO FIVE INCHES OF SNOW. MEANWHILE AREAS SOUTH AND EAST OF GRAND RAPIDS SHOULD GENERALLY SEE AN INCH OR TWO. THE ACTIVE WEATHER LOOKS TO FINALLY CALM DOWN BY FRIDAY AND INTO EARLY NEXT WEEK. TEMPERATURES WILL ALSO BECOME A BIT MILDER WITH DAYTIME HIGHS MAINLY 35 TO 40 FROM FRIDAY INTO EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1120 AM EST WED NOV 27 2013 WORKING ON DROPPING ALLEGAN FROM LAKE EFFECT ADVISORY FOR THE AFTERNOON. HRRR AND 12Z NSSL WRF SUPPORT SHOW MAIN SNOW BAND WILL STAY OFFSHORE OF ALLEGAN COUNTY THROUGH THE AFTERNOON BEFORE POTENTIALLY MOVING BACK ONSHORE BEFORE BREAKING UP THIS EVENING. LOOKS LIKE BAND WILL MAINLY AFFECT THE SOUTHERN HALF OF VAN BUREN THROUGH THE AFTERNOON WITH LOCAL SNOWFALL EXCEEDING AN INCH PER HOUR. THAT SHOULD RESULT IN A SWATH OF LOCALLY 5 TO 9 INCH EVENT TOTALS FROM SOUTH HAVEN SOUTHWARD TOWARDS BENTON HARBOR. ADVISORY FOR MASON/OCEANA COUNTIES LOOK GOOD WITH ADDITIONAL LOCAL ACCUMULATIONS OF 1 TO 3 INCHES. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 326 AM EST WED NOV 27 2013 ACTIVE SHORT TERM WILL CONTINUE FOR ANOTHER 48 HOURS...THEN WE FINALLY SEE A PATTERN CHANGE. WILL KEEP HEADLINES AS IS FOR NOW. HOWEVER IT APPEARS THIS EVENT MAY UNDER PERFORM SOMEWHAT FROM WHAT WAS EARLIER FORECASTED. IN LARGE PART THIS SEEMS TO BE DUE TO MOISTURE DEPTH AS INVERSION HEIGHTS WHERE ONLY 6-7K FT. ANOTHER FACTOR THAT SHOULD COME INTO PLAY TOWARD MID DAY WILL BE 35 KNOTS WINDS NEAR THE CLOUD TOPS SHOULD MAY INTRODUCE AN ELEMENT OF SHEAR...NOT ALLOWING THE BANDS TO BECOME TOO ORGANIZED. DESPITE THIS...IT WILL STILL BE SNOWING WEST OF U.S. 131 WITH A 335-340 FLOW DOMINATING THROUGH THE DAY. THIS WILL GIVE THE COASTAL AREAS THE HIGHEST SNOW POTENTIAL WHERE TWO TO FOUR INCHES OF ADDITIONAL ACCUMS IS LIKELY TODAY. HOWEVER THERE SHOULD BE A DIMINISHING TREND THROUGH THE AFTERNOON WITH THE INCREASED SHEAR AND WITH THE FLOW APPEARING TO GO ANTICYCLONIC QUICKER. WE MAY BE ABLE TO CANCEL THE ADVISORY EARLY...PERHAPS BY MID AFTERNOON. THE NEXT SYSTEM WILL BE RIGHT ON OUR HEELS BY DAYBREAK THURSDAY. THIS WILL BE ANOTHER CLIPPER...WITH THE SHORT WAVE SEEN OF WATER VAPOR THIS MORNING NW OF LAKE WINNIPEG. THIS SYSTEM CONTINUES TO LOOK MORE INTERESTING AS IT SHOULD HAVE A SW FLOW LAKE ENHANCEMENT ELEMENT TO IT. MOISTURE DEPTH IS PROGGED TO BE EVEN BETTER THEN THIS MORNING/S EVENT. THE FLOW THEN TURNS WNW THURSDAY EVENING... WITH DECENT MOISTURE DEPTH LINGERING. HAVE DUMPED UP POPS AND ACCUMS WITH THIS SYSTEM...ESPECIALLY FOR AREAS FROM GRR NORTH AND WEST. WE MAY NEED ANOTHER ADVISORY TO COVER THIS EVENT... CONSIDERING THE IMPACT TO HOLIDAY TRAVELERS. THE PROGRESSIVE PATTERN SHOULD LEAD TO ANOTHER PERIOD OF ANTICYCLONIC FLOW TOWARD DAYBREAK FRIDAY...SO ANY LAKE EFFECT SHOULD DIMINISH LATE THURSDAY NIGHT. SURFACE HIGH PRESSURE BUILDS IN BY FRIDAY ALONG WITH MORE OF A ZONAL FLOW. LOOKS LIKE QUIET WEATHER FOR BLACK FRIDAY WITH SOME SUN COMING THROUGH. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 326 AM EST WED NOV 27 2013 THE LONG TERM PERIOD LOOKS RATHER UNEVENTFUL AS THE POLAR JET AND COLD AIR RETREATS FOR AWHILE. TEMPERATURES WILL UNDERGO A MODERATING TREND WITH HIGHS RECOVERING TO CLOSER TO NORMAL VALUES FOR THIS TIME OF YEAR...NEAR 40. NO MAJOR STORMS ARE EXPECTED AND NO BIG COOL DOWNS OR WARM UPS WILL OCCUR. ONLY OCCASIONAL LOW PROBABILITIES FOR LIGHT SNOW OR MIXED LIGHT RAIN AND SNOW ARE FORECAST. SEVERAL WEAK SHORTWAVES MOVING THROUGH A RELATIVELY FLAT/ZONAL ALOFT WILL BRING THE OCCASIONAL LOW CHANCES OF LIGHT PRECIPITATION. ONE WAVE AND ASSOCIATED SFC TROUGH/COLD FRONT ARRIVES SATURDAY NIGHT THEN EXITS EARLY SUNDAY. AFTER THAT THE TIMING OF THESE WEAK FEATURES BECOMES QUITE SKETCHY AND RESULTS IN LOW /20-30 PCT/ POPS IN SEVERAL CONSECUTIVE FCST PERIODS. IT IS VERY POSSIBLE THAT WE WILL BE ABLE TO REMOVE CHANCES OF PRECIP ENTIRELY FOR SUNDAY NIGHT THROUGH TUESDAY IN LATER FORECASTS. MODELS ARE HINTING AT A SFC HIGH BECOMING ESTABLISHED TO OUR NORTH OVER ONTARIO WITH A RIDGE EXTENDING SOUTH ACROSS THE GRTLKS REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1248 PM EST WED NOV 27 2013 MAIN ISSUES FOR THE 18Z FCSTS WILL BE LAKE EFFECT TRENDS AND THEN SNOW TRENDS FOR THU AS THE NEXT WAVE OF LOW PRESSURE MOVES THROUGH. BAND OF LAKE EFFECT HAS MOVED WEST OF ALL THE TERMINALS AND OVER THE ERN PORTION OF LAKE MICHIGAN WITH A FLOW FROM NORTH. SOME DIURNAL CLOUD COVER HAS FORMED OVER INLAND AREAS...MORE CONCENTRATED EAST OF U.S.-131. THIS WAVE A MIX OF VFR AND MVFR...WHICH HAS NOW LIFTED TO MAINLY ALL VFR NOW. WE EXPECT THIS WILL NOT BE AN ISSUE. FLOW WILL TRANSITION TO MORE FROM THE NW THIS EVENING...AND EVENTUALLY FROM THE SW OVERNIGHT TONIGHT. THIS WILL SHIFT THE LAKE SNOW BAND INLAND. THIS WILL BRING A BRIEF YET MODERATE BURST OF SNOW TO THE AREA FROM WEST TO EAST LATE TONIGHT AND INTO THU MORNING WITH THE HIGHER IMPACT AT WRN TERMINALS. SOME IFR WILL BE POSSIBLE IN THIS BURST ESPECIALLY WEST BEFORE IT BREAKS UP. SNOW WILL DEVELOP THEN AT KMKG AND KGRR AND AREAS NORTH THU MORNING AS A WAVE OF LOW PRESSURE MOVES THROUGH. LAKE MICHIGAN WILL HELP TO ENHANCE THIS SNOW. THIS SHOULD BRING SOLID IFR CONDITIONS AND LOWER TO KMKG AND AREAS NORTH INTO EARLY THU AFTERNOON. CONDITIONS SHOULD START TO IMPROVE AFTER 18Z THU AS THE SNOW BEGINS TO MOVE OUT. && .MARINE... ISSUED AT 326 AM EST WED NOV 27 2013 SCA WILL BE MAINTAINED THROUGH TONIGHT. WE MAY NEED TO EXTEND IT INTO THURSDAY...BUT CONDITIONS BY THEN LOOK FAIRLY MARGINAL AND WILL EVALUATE WITH FURTHER FORECAST PACKAGES. THURSDAY NIGHT AND FRIDAY LOOKS CALMER WITH HIGH PRESSURE BUILDING IN. && .HYDROLOGY... ISSUED AT 326 AM EST WED NOV 27 2013 ALL PCPN IN THE SHORT TERM SHOULD BE SNOW AND NO HYDRO IMPACTS ARE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST THURSDAY FOR MIZ037-043- 071. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ844>849. && $$ UPDATE...COBB SYNOPSIS...JK SHORT TERM...JK LONG TERM...MEADE AVIATION...NJJ HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1118 AM EST WED NOV 27 2013 LATEST UPDATE... .SYNOPSIS... ISSUED AT 326 AM EST WED NOV 27 2013 LAKE EFFECT SNOW SHOWERS WILL CONTINUE TODAY MAINLY WEST OF U.S. 131. ADDITIONAL ACCUMULATIONS OF ONE TO FOUR INCHES CAN BE EXPECTED BEFORE THE PRECIPITATION DWINDLES THIS EVENING. MEANWHILE AREAS EAST OF U.S. 131 WILL SEE LITTLE TO NO ACCUMULATION. AFTER A QUIET PERIOD TONIGHT...ANOTHER CLIPPER SYSTEM WILL BRING ANOTHER ROUND OF SNOW TO ALL OF SOUTHWEST MICHIGAN STARTING TOWARD DAYBREAK THANKSGIVING DAY. THE SNOW WILL BE ENHANCED BY LAKE MICHIGAN AND PORTIONS OF WEST CENTRAL LOWER MICHIGAN SHOULD SEE THREE TO FIVE INCHES OF SNOW. MEANWHILE AREAS SOUTH AND EAST OF GRAND RAPIDS SHOULD GENERALLY SEE AN INCH OR TWO. THE ACTIVE WEATHER LOOKS TO FINALLY CALM DOWN BY FRIDAY AND INTO EARLY NEXT WEEK. TEMPERATURES WILL ALSO BECOME A BIT MILDER WITH DAYTIME HIGHS MAINLY 35 TO 40 FROM FRIDAY INTO EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1120 AM EST WED NOV 27 2013 WORKING ON DROPPING ALLEGAN FROM LAKE EFFECT ADVISORY FOR THE AFTERNOON. HRRR AND 12Z NSSL WRF SUPPORT SHOW MAIN SNOW BAND WILL STAY OFFSHORE OF ALLEGAN COUNTY THROUGH THE AFTERNOON BEFORE POTENTIALLY MOVING BACK ONSHORE BEFORE BREAKING UP THIS EVENING. LOOKS LIKE BAND WILL MAINLY AFFECT THE SOUTHERN HALF OF VAN BUREN THROGH THE AFTERNOON WITH LOCAL SNOWFALL EXCEEDING AN INCH PER HOUR. THAT SHOULD RESULT IN A SWATH OF LOCALLY 5 TO 9 INCHE EVENT TOTALS FROM SOUTH HAVEN SOUTHWARD TOWARDS BENTON HARBOR. ADVISORY FOR MASON/OCEANA COUNTIES LOOK GOOD WITH ADDITIONAL LOCAL ACCUMULATIONS OF 1 TO 3 INCHES. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 326 AM EST WED NOV 27 2013 ACTIVE SHORT TERM WILL CONTINUE FOR ANOTHER 48 HOURS...THEN WE FINALLY SEE A PATTERN CHANGE. WILL KEEP HEADLINES AS IS FOR NOW. HOWEVER IT APPEARS THIS EVENT MAY UNDER PERFORM SOMEWHAT FROM WHAT WAS EARLIER FORECASTED. IN LARGE PART THIS SEEMS TO BE DUE TO MOISTURE DEPTH AS INVERSION HEIGHTS WHERE ONLY 6-7K FT. ANOTHER FACTOR THAT SHOULD COME INTO PLAY TOWARD MID DAY WILL BE 35 KNOTS WINDS NEAR THE CLOUD TOPS SHOULD MAY INTRODUCE AN ELEMENT OF SHEAR...NOT ALLOWING THE BANDS TO BECOME TOO ORGANIZED. DESPITE THIS...IT WILL STILL BE SNOWING WEST OF U.S. 131 WITH A 335-340 FLOW DOMINATING THROUGH THE DAY. THIS WILL GIVE THE COASTAL AREAS THE HIGHEST SNOW POTENTIAL WHERE TWO TO FOUR INCHES OF ADDITIONAL ACCUMS IS LIKELY TODAY. HOWEVER THERE SHOULD BE A DIMINISHING TREND THROUGH THE AFTERNOON WITH THE INCREASED SHEAR AND WITH THE FLOW APPEARING TO GO ANTICYCLONIC QUICKER. WE MAY BE ABLE TO CANCEL THE ADVISORY EARLY...PERHAPS BY MID AFTERNOON. THE NEXT SYSTEM WILL BE RIGHT ON OUR HEELS BY DAYBREAK THURSDAY. THIS WILL BE ANOTHER CLIPPER...WITH THE SHORT WAVE SEEN OF WATER VAPOR THIS MORNING NW OF LAKE WINNIPEG. THIS SYSTEM CONTINUES TO LOOK MORE INTERESTING AS IT SHOULD HAVE A SW FLOW LAKE ENHANCEMENT ELEMENT TO IT. MOISTURE DEPTH IS PROGGED TO BE EVEN BETTER THEN THIS MORNING/S EVENT. THE FLOW THEN TURNS WNW THURSDAY EVENING... WITH DECENT MOISTURE DEPTH LINGERING. HAVE DUMPED UP POPS AND ACCUMS WITH THIS SYSTEM...ESPECIALLY FOR AREAS FROM GRR NORTH AND WEST. WE MAY NEED ANOTHER ADVISORY TO COVER THIS EVENT... CONSIDERING THE IMPACT TO HOLIDAY TRAVELERS. THE PROGRESSIVE PATTERN SHOULD LEAD TO ANOTHER PERIOD OF ANTICYCLONIC FLOW TOWARD DAYBREAK FRIDAY...SO ANY LAKE EFFECT SHOULD DIMINISH LATE THURSDAY NIGHT. SURFACE HIGH PRESSURE BUILDS IN BY FRIDAY ALONG WITH MORE OF A ZONAL FLOW. LOOKS LIKE QUIET WEATHER FOR BLACK FRIDAY WITH SOME SUN COMING THROUGH. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 326 AM EST WED NOV 27 2013 THE LONG TERM PERIOD LOOKS RATHER UNEVENTFUL AS THE POLAR JET AND COLD AIR RETREATS FOR AWHILE. TEMPERATURES WILL UNDERGO A MODERATING TREND WITH HIGHS RECOVERING TO CLOSER TO NORMAL VALUES FOR THIS TIME OF YEAR...NEAR 40. NO MAJOR STORMS ARE EXPECTED AND NO BIG COOL DOWNS OR WARM UPS WILL OCCUR. ONLY OCCASIONAL LOW PROBABILITIES FOR LIGHT SNOW OR MIXED LIGHT RAIN AND SNOW ARE FORECAST. SEVERAL WEAK SHORTWAVES MOVING THROUGH A RELATIVELY FLAT/ZONAL ALOFT WILL BRING THE OCCASIONAL LOW CHANCES OF LIGHT PRECIPITATION. ONE WAVE AND ASSOCIATED SFC TROUGH/COLD FRONT ARRIVES SATURDAY NIGHT THEN EXITS EARLY SUNDAY. AFTER THAT THE TIMING OF THESE WEAK FEATURES BECOMES QUITE SKETCHY AND RESULTS IN LOW /20-30 PCT/ POPS IN SEVERAL CONSECUTIVE FCST PERIODS. IT IS VERY POSSIBLE THAT WE WILL BE ABLE TO REMOVE CHANCES OF PRECIP ENTIRELY FOR SUNDAY NIGHT THROUGH TUESDAY IN LATER FORECASTS. MODELS ARE HINTING AT A SFC HIGH BECOMING ESTABLISHED TO OUR NORTH OVER ONTARIO WITH A RIDGE EXTENDING SOUTH ACROSS THE GRTLKS REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 657 AM EST WED NOV 27 2013 PREDOMINATELY VFR CONDITIONS EXPECTED TODAY AND TONIGHT AT MOST OF THE TERMINALS AS LAKE EFFECT SNOW BANDS CONTINUE TO HUG THE COASTLINE. KMKG COULD SEE OCNL MVFR CIGS/VSBYS IN SNOW SHOWERS. NORTHWEST SFC WINDS WILL INCREASE BY MID MORNING AND BECOME GUSTY TO 25 KTS. THE WINDS WILL DIMINISH BELOW 10 KTS AFTER 00Z TONIGHT. WIDESPREAD LIGHT SNOW OR FLURRIES WILL DEVELOP AFTER 09Z MAINLY WEST OF LAN AND JXN AS WINDS SWING AROUND TO THE SOUTHWEST. WE COULD SEE SOME IFR VSBYS IN SNOW DEVELOPING AT KMKG BY 12Z. && .MARINE... ISSUED AT 326 AM EST WED NOV 27 2013 SCA WILL BE MAINTAINED THROUGH TONIGHT. WE MAY NEED TO EXTEND IT INTO THURSDAY...BUT CONDITIONS BY THEN LOOK FAIRLY MARGINAL AND WILL EVALUATE WITH FURTHER FORECAST PACKAGES. THURSDAY NIGHT AND FRIDAY LOOKS CALMER WITH HIGH PRESSURE BUILDING IN. && .HYDROLOGY... ISSUED AT 326 AM EST WED NOV 27 2013 ALL PCPN IN THE SHORT TERM SHOULD BE SNOW AND NO HYDRO IMPACTS ARE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST THURSDAY FOR MIZ037-043- 064-071. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ844>849. && $$ UPDATE...COBB SYNOPSIS...JK SHORT TERM...JK LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
229 PM CST WED NOV 27 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 215 PM CST WED NOV 27 2013 EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH GFS 27.12 HEIGHTS AND WINDS IMMEDIATELY IDENTIFIED A LONG WAVE TROUGH ACROSS THE EASTERN CONUS...WITH A CYCLONE DOWNSTREAM OF THIS TROUGH AXIS. NORTHWEST FLOW PREVAILED ACROSS THE CENTRAL CONUS UPSTREAM OF THE TROUGH AXIS. A WEAK SHORTWAVE ALONG THE ND/MN BORDER WAS EMBEDDED IN THIS NORTHWEST FLOW. WARM AIR ADVECTION AHEAD IF THIS SHORTWAVE TOGETHER WITH THE UPPER LEVEL DYNAMICS ASSOCIATED WITH THE 5M/HR HEIGHT FALLS WERE THE DRIVING FORCE BEHIND AN AREA OF SNOW ACROSS NORTHERN MINNESOTA. THIS EVENING THE FORCING WILL WEAKEN...BUT SNOW SHOULD CONTINUE TO SPREAD SOUTHEASTWARD INTO NORTHERN WISCONSIN. THE NORTHEASTERN COUNTIES IN THE CWA WILL BE RIGHT ON THE EDGE OF THIS SNOW...BUT FORECAST SOUNDINGS FOR EAU CLAIRE AND NEW RICHMOND WOULD SUPPORT AT LEAST A FEW HOURS OF SNOW. THE LOW LEVEL DRY AIR WILL DELAY THE ONSET UNTIL CLOSER TO 00Z THIS EVENING. SNOW TOTALS WILL BE LESS THAN AN INCH...AND SHOULD TAPER OFF TO FLURRIES BY THURSDAY MORNING. THE CHALLENGE FOR THURSDAYS FORECAST WAS THE CLOUD COVER. INCREASED IT SLIGHTLY BASED OFF THE 0-1RH FROM BOTH THE NAM AND RAP WHICH SEEM TO HAVE A GOOD HANDLE ON THE STRATUS CURRENTLY ENTERING NORTHERN NORTH DAKOTA. ALSO LOWERED HIGH TEMPS A COUPLE OF DEGREES BECAUSE OF THE INCREASED CLOUD COVER. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 215 PM CST WED NOV 27 2013 BIG CHGS ARE EXPECTED NEXT WEEK AS A SIGNIFICANT ARCTIC AIR MASS SURGES SOUTHWARD ACROSS THE WESTERN CONUS...AND EVENTUALLY TAKING HOLD OF MOST OF THE U.S...WITH THE EXCEPTION IN THE DEEP SE. CURRENT LONG WAVE PATTERN REMAINS FROM THE NW ACROSS THE UPPER MIDWEST ALONG WITH A SPLIT FLOW REGIME FOR THE REMAINDER OF THE CONUS. THE SOUTHERN STREAM HAS BEEN THE MOST ACTIVE IN RECENT WEEKS...TAKING THE BULK OF THE SIGNIFICANT WX TRACKS SOUTH AND EAST OF THE UPPER MIDWEST. ALTHOUGH SOME TIMING AND STRENGTH PARAMETERS REMAIN UNCLEAR IN THE DETERMINISTIC RUNS FROM BOTH THE EC/GFS...THERE REMAINS ONE THEME...A SIGNIFICANT COLD AIR MASS WILL INVADE MOST OF THE U.S. STARTING THIS WEEKEND IN THE PACIFIC NW...AND EVENTUALLY THE ROCKIES/PLAINS/GREAT LAKES BY THE FOLLOWING WEEKEND. USUALLY MODELS ARE TOO FAST ON PATTERN CHGS...AND THIS IS EVIDENT WITH EACH MODEL RUN. ALTHOUGH THE EC HAS BEEN THE STRONGEST ON THE DEEP TROUGH DEVELOPING ACROSS MOST OF THE WESTERN/CENTRAL PART OF THE U.S. BY LATE NEXT WEEK...THE ENSEMBLE MEANS /EC & GFS/ HAVE CONTINUED TO KEEP A MORE PROGRESSIVE WX PATTERN. EVEN THE LATEST EC 12Z/27 RUN HAS A MORE PRONOUNCED DEEP TROUGH ACROSS THE NORTHERN ROCKIES BY THE END OF NEXT WEEK COMPARED TO THE 50H ENSEMBLE MEAN. BASICALLY WITH THE STRONGER AND DEEPER TROUGH...STORM SYSTEMS WILL LIKELY BE SLOWER ON THE ONSET OF SFC LOW /BOMBS/ DEVELOPING ACROSS THE PLAINS. OVER THE PAST 3-5 RUNS OF THE EC...THE SFC LOW AND ASSOCIATED ARCTIC BOUNDARY KEEPS GETTING PUSHED BACK IN TIME ON THE EVOLUTION OF A STRONG STORM SYSTEM IN THE PLAINS. THIS WILL LIKELY KEEP OUR REGION UNEVENTFUL UNTIL LATE IN THE PERIOD...AND POSSIBLY OUTSIDE OUR 7 DAY FORECAST IF THE TROUGH IN THE WEST CONTINUES TO DEEPEN. IN ADDITION TO THE SLOWER PACE OF THE STORM SYSTEM MOVING OUT INTO THE PLAINS...THE LARGE AREA OF ARCTIC HIGH PRESSURE CIRCULATING FROM THE EASTERN CANADA...AND ACROSS THE GREAT LAKES /EAST & NE FLOW IN THE BOUNDARY LAYER/...KEEPS OUR REGION RELATIVELY DRY. THEREFORE...I AM NOT CONFIDENT ON ANY CHC OF PRECIPITATION NEXT WEEK UNTIL THIS SYSTEM MOVES OUT INTO THE PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1115 AM CST WED NOV 27 2013 AREA OF SNOW ACROSS NORTHERN MINNESOTA WILL WEAKEN AS IT MOVES SOUTHEAST...AND COULD GRAZE KRNH/KEAU WITH REDUCED VSBYS LATER THIS AFTERNOON. HOWEVER CONFIDENCE IS LOW...SO NARROWED THE TIMING WINDOW. ONCE THIS MOVES THROUGH WINDS WILL BECOME NORTHWESTERLY...AND THIS COULD BRING LOW STRATUS BY THURSDAY MORNING. FOR NOW WENT WITH A SCATTERED DECK...BUT MAY HAVE TO INCREASE TO BROKEN BASED ON THE UPSTREAM OBS AND FORECAST SOUNDINGS FROM THE NAM AND RAP. KMSP... NO BIG DIFFERENCES FROM GENERALLY AVIATION DISCUSSION. SNOW SHOULD REMAIN EAST OF THE METRO...WITH THE MAIN CONCERN BEING MVFR CIGS THURSDAY. FOR NOW JUST WENT WITH SCATTERED DECK...BUT AS ALLUDED TO ABOVE MAY HAVE TO INCREASE THIS TO BROKEN. IF CIGS DO DEVELOP...THEY SHOULD REMAIN ABOVE 1700FT. /OUTLOOK FOR KMSP/ FRI...VFR. WINDS SE AT 5-10KTS. SAT...VFR. WINDS SW AT 5-10KTS. SUN...VFR WITH MVFR AND -SN POSSIBLE. WINDS NE AT 5-10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JRB LONG TERM...JLT AVIATION...JRB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
109 PM CST WED NOV 27 2013 .UPDATE... ISSUED AT 1241 PM CST WED NOV 27 2013 MADE SOME ADJUSTMENTS TO MIDDAY TEMPS AND SKY COVER. STRATUS WILL CONTINUE TO MOVE SOUTH INTO THE FORECAST AREA THIS AFTERNOON WITH A FEW FLURRIES. WIND TRAJECTORIES SUGGEST LAKE ENHANCED MOISTURE MAY ALSO CONTRIBUTE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CST WED NOV 27 2013 CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHWESTERN SASKATCHEWAN/NORTH CENTRAL MONTANA. SOUTH WINDS AHEAD OF THE SYSTEM HAD DEVELOPED OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENING HOURS...AND STRONG WARM ADVECTION CONTINUED OVER THE WESTERN HALF OF NORTH DAKOTA AHEAD OF THIS SYSTEM. REGARDING TEMPERATURES...READINGS HAD RISEN INTO THE LOWER 20S ACROSS FAR WESTERN NORTH DAKOTA...AND INTO THE TEENS OVER WESTERN PORTIONS OF CENTRAL NORTH DAKOTA. THIS TREND OF RISING TEMPERATURES SHOULD CONTINUE EASTWARD THROUGH SUNRISE. ALONG WITH THE WARM ADVECTION...IT APPEARS THAT THE RUC MODEL HAS A VERY GOOD HANDLE ON H850 TO H700 LIFTING OCCURRING OVER SOUTHEASTERN SASKATCHEWAN/SOUTHWEST MANITOBA/NORTHERN NORTH DAKOTA. THIS MODEL WAS DEPICTING LIGHT PRECIPITATION OVER THIS SAME AREA AROUND MIDNIGHT...AND IT CONTINUES/ADVECTS IT EASTWARD DURING THE REST OF THE NIGHTTIME HOURS. CURRENT RADAR LOOPS VALIDATING AT LEAST SOME ENHANCED CLOUDS AND/OR LIFT OCCURRING...SO WILL KEEP A MENTION OF FLURRIES FOR THIS TIME PERIOD OVER NORTH CENTRAL TO THE JAMESTOWN AREA THROUGH SUNRISE. THE 06Z NAM AS WELL AS THE 00Z ECMWF AND GFS MODELS ARE NOW DEPICTING LIGHT PRECIPITATION OVER NORTHEASTERN NORTH DAKOTA FROM 6 AM TO NOON TIME FRAME. THIS APPEARS TO BE THE RESULT OF BOTH WARM ADVECTION LIFTING AT H850/H700 AS WELL AS REINFORCEMENT FROM AN UPPER LEVEL SHORTWAVE MOVING SOUTHEAST OUT OF MANITOBA. ADDED A MENTION OF CHANCE OF LIGHT SNOW THIS MORNING IN THE BOTTINEAU/TURTLE MOUNTAIN/HARVEY AREA. CONTINUED WARM ADVECTION THROUGH THE DAY UNTIL A COLD FRONT DIVES SOUTHEAST OUT OF SASKATCHEWAN THIS AFTERNOON SWEEPING ACROSS THE STATE AND REACHING THE JAMES RIVER VALLEY LATE AFTERNOON/EVENING. SOUTH WINDS AHEAD OF THE FRONT WILL BECOME NORTHWEST AT AROUND 15 MPH. EXPECTING HIGH TEMPERATURES TO REACH INTO THE 20S OVER NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THROUGH THE JAMES RIVER VALLEY...WITH TEMPERATURES IN THE 30S MAINLY SOUTH AND WEST OF THE MISSOURI RIVER. THE FAR SOUTHWEST MAY SEE TEMPERATURES REACH INTO THE LOWER 40S. THE COLD FRONT WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH PRESSURE SYSTEM...AND EXPECTING LOWS TONIGHT FROM THE SINGLE DIGITS NORTH TO LOWER TEENS SOUTH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CST WED NOV 27 2013 FORECAST HIGHLIGHTS IN THE LONG TERM PERIOD WILL BY MAINLY DRY CONDITIONS THROUGH SATURDAY NIGHT...FOLLOWED BY A POSSIBLE VERY ACTIVE WEATHER PERIOD SOMETIME FROM SUNDAY INTO THE MIDDLE PORTIONS OF NEXT WEEK. THE EXTENDED PERIOD BEGINS THURSDAY MORNING WITH STRONG NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS AND A SFC RIDGE OF HIGH PRESSURE EXTENDING FROM NORTH OF MANITOBA SOUTH THROUGH THE DAKOTAS. BOTH THE 00Z NAM/GFS CONTINUE TO INDICATE LOW STRATUS FROM WEDNESDAY NIGHT PERSISTING INTO THURSDAY MORNING ACROSS MUCH OF WEST AND CENTRAL NORTH DAKOTA WITH THE SFC RIDGE. COUPLED WITH SUBTLE MID/UPPER LEVEL SUPPORT...OPTED TO CONTINUE THE ISOLATED FLURRY MENTION FROM WED NIGHT INTO MID MORNING THURSDAY. WILL SEE A PATTERN CHANGE STARTING ON FRIDAY AS UPPER LEVEL LOW PRESSURE OVER EASTERN CANADA THURSDAY LIFTS MORE NORTHEAST TOWARDS WESTERN GREENLAND FRI-SAT. THIS TRANSITIONS OUR FLOW ALOFT FROM STRONG NORTHWESTERLY TO A WEAKER NORTHWESTERLY BY SATURDAY...AND EVENTUALLY QUASI-ZONAL BY SUNDAY. WILL MAINTAIN DRY CONDITIONS AND A SLOW WARM-UP UNDER THIS FLOW PATTERN THROUGH SAT NIGHT. AS THIS CHANGE IS OCCURRING...STRONG UPPER LOW OVER ALASKA ON THURSDAY WILL MOVE SLOWLY SOUTHEAST ALONG THE CANADIAN PACIFIC SHORE SATURDAY NIGHT INTO SUNDAY...THEN INTO THE PACIFIC NORTHWEST BY EARLY MONDAY. LEAD EMBEDDED IMPULSES WITHIN THIS FEATURE MAY BRING PRECIPITATION TO THE DAKOTAS AS EARLY AS SUNDAY DAYTIME (00Z ECMWF)...OR MAY HOLD OFF UNTIL MONDAY (00Z GFS). THUS MODELS STILL SHOWING LOTS OF UNCERTAINTY ONLY 4-5 DAYS OUT. WAA AHEAD OF THIS SYSTEM WOULD SUPPORT A VARIETY OF PRECIPITATION TYPES...DEPENDING WHETHER WE SEE PRECIP AT NIGHT OR IN THE DAYTIME. UNCERTAINTY COMPOUNDS AS WE GO FORWARD INTO THE EARLY TO MIDDLE PORTIONS OF NEXT WEEK AS THE UPPER LOW EVOLVES. THE LATEST GFS PRODUCES SPLIT FLOW DEVELOPING MONDAY NIGHT INTO TUESDAY...WITH THE BULK OF ASSOCIATED PRECIPITATION OFF TO OUR NORTH IN CANADA. THE LATEST 00Z ECMWF (MUCH SLOWER THAN THE 12Z ECMWF) MAINTAINS A CLOSED SYSTEM AND DOES IMPACT WEST AND NORTH CENTRAL PARTS OF THE STATE WITH WINTER WEATHER. ALL SOLUTIONS BRING IN MUCH COLDER AIR SOMETIME TUESDAY OR WEDNESDAY. WILL CONTINUE TO MONITOR IN THE COMING DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1241 PM CST WED NOV 27 2013 MVFR STRATUS WILL CONTINUE TO DROP SOUTH FROM CANADA...IMPACTING TAF SITES FROM 19Z AT KISN TO 01Z THIS EVENING AT KJMS. A FEW FLURRIES MAY ACCOMPANY THE LOW CLOUDS...WITH POSSIBLE CONTRIBUTIONS FROM LAKE ENHANCED MOISTURE. W/SW WINDS WILL BECOME NORTHWEST THIS AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...JV LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1040 AM CST WED NOV 27 2013 .UPDATE... ISSUED AT 1004 AM CST WED NOV 27 2013 LOW CLOUDS CONTINUE TO MAKE QUICK PROGRESS AND WILL SPREAD INTO NORTHERN NORTH DAKOTA BY MIDDAY. ISOLATED FLURRIES STILL EXPECTED WITH STRATUS DECK. ALSO RAISED TEMPERATURES SLIGHTLY IN THE SOUTHWEST AFTER FAST WARMING THROUGH LATE MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CST WED NOV 27 2013 CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHWESTERN SASKATCHEWAN/NORTH CENTRAL MONTANA. SOUTH WINDS AHEAD OF THE SYSTEM HAD DEVELOPED OVER WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENING HOURS...AND STRONG WARM ADVECTION CONTINUED OVER THE WESTERN HALF OF NORTH DAKOTA AHEAD OF THIS SYSTEM. REGARDING TEMPERATURES...READINGS HAD RISEN INTO THE LOWER 20S ACROSS FAR WESTERN NORTH DAKOTA...AND INTO THE TEENS OVER WESTERN PORTIONS OF CENTRAL NORTH DAKOTA. THIS TREND OF RISING TEMPERATURES SHOULD CONTINUE EASTWARD THROUGH SUNRISE. ALONG WITH THE WARM ADVECTION...IT APPEARS THAT THE RUC MODEL HAS A VERY GOOD HANDLE ON H850 TO H700 LIFTING OCCURRING OVER SOUTHEASTERN SASKATCHEWAN/SOUTHWEST MANITOBA/NORTHERN NORTH DAKOTA. THIS MODEL WAS DEPICTING LIGHT PRECIPITATION OVER THIS SAME AREA AROUND MIDNIGHT...AND IT CONTINUES/ADVECTS IT EASTWARD DURING THE REST OF THE NIGHTTIME HOURS. CURRENT RADAR LOOPS VALIDATING AT LEAST SOME ENHANCED CLOUDS AND/OR LIFT OCCURRING...SO WILL KEEP A MENTION OF FLURRIES FOR THIS TIME PERIOD OVER NORTH CENTRAL TO THE JAMESTOWN AREA THROUGH SUNRISE. THE 06Z NAM AS WELL AS THE 00Z ECMWF AND GFS MODELS ARE NOW DEPICTING LIGHT PRECIPITATION OVER NORTHEASTERN NORTH DAKOTA FROM 6 AM TO NOON TIME FRAME. THIS APPEARS TO BE THE RESULT OF BOTH WARM ADVECTION LIFTING AT H850/H700 AS WELL AS REINFORCEMENT FROM AN UPPER LEVEL SHORTWAVE MOVING SOUTHEAST OUT OF MANITOBA. ADDED A MENTION OF CHANCE OF LIGHT SNOW THIS MORNING IN THE BOTTINEAU/TURTLE MOUNTAIN/HARVEY AREA. CONTINUED WARM ADVECTION THROUGH THE DAY UNTIL A COLD FRONT DIVES SOUTHEAST OUT OF SASKATCHEWAN THIS AFTERNOON SWEEPING ACROSS THE STATE AND REACHING THE JAMES RIVER VALLEY LATE AFTERNOON/EVENING. SOUTH WINDS AHEAD OF THE FRONT WILL BECOME NORTHWEST AT AROUND 15 MPH. EXPECTING HIGH TEMPERATURES TO REACH INTO THE 20S OVER NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THROUGH THE JAMES RIVER VALLEY...WITH TEMPERATURES IN THE 30S MAINLY SOUTH AND WEST OF THE MISSOURI RIVER. THE FAR SOUTHWEST MAY SEE TEMPERATURES REACH INTO THE LOWER 40S. THE COLD FRONT WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH PRESSURE SYSTEM...AND EXPECTING LOWS TONIGHT FROM THE SINGLE DIGITS NORTH TO LOWER TEENS SOUTH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CST WED NOV 27 2013 FORECAST HIGHLIGHTS IN THE LONG TERM PERIOD WILL BY MAINLY DRY CONDITIONS THROUGH SATURDAY NIGHT...FOLLOWED BY A POSSIBLE VERY ACTIVE WEATHER PERIOD SOMETIME FROM SUNDAY INTO THE MIDDLE PORTIONS OF NEXT WEEK. THE EXTENDED PERIOD BEGINS THURSDAY MORNING WITH STRONG NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS AND A SFC RIDGE OF HIGH PRESSURE EXTENDING FROM NORTH OF MANITOBA SOUTH THROUGH THE DAKOTAS. BOTH THE 00Z NAM/GFS CONTINUE TO INDICATE LOW STRATUS FROM WEDNESDAY NIGHT PERSISTING INTO THURSDAY MORNING ACROSS MUCH OF WEST AND CENTRAL NORTH DAKOTA WITH THE SFC RIDGE. COUPLED WITH SUBTLE MID/UPPER LEVEL SUPPORT...OPTED TO CONTINUE THE ISOLATED FLURRY MENTION FROM WED NIGHT INTO MID MORNING THURSDAY. WILL SEE A PATTERN CHANGE STARTING ON FRIDAY AS UPPER LEVEL LOW PRESSURE OVER EASTERN CANADA THURSDAY LIFTS MORE NORTHEAST TOWARDS WESTERN GREENLAND FRI-SAT. THIS TRANSITIONS OUR FLOW ALOFT FROM STRONG NORTHWESTERLY TO A WEAKER NORTHWESTERLY BY SATURDAY...AND EVENTUALLY QUASI-ZONAL BY SUNDAY. WILL MAINTAIN DRY CONDITIONS AND A SLOW WARM-UP UNDER THIS FLOW PATTERN THROUGH SAT NIGHT. AS THIS CHANGE IS OCCURRING...STRONG UPPER LOW OVER ALASKA ON THURSDAY WILL MOVE SLOWLY SOUTHEAST ALONG THE CANADIAN PACIFIC SHORE SATURDAY NIGHT INTO SUNDAY...THEN INTO THE PACIFIC NORTHWEST BY EARLY MONDAY. LEAD EMBEDDED IMPULSES WITHIN THIS FEATURE MAY BRING PRECIPITATION TO THE DAKOTAS AS EARLY AS SUNDAY DAYTIME (00Z ECMWF)...OR MAY HOLD OFF UNTIL MONDAY (00Z GFS). THUS MODELS STILL SHOWING LOTS OF UNCERTAINTY ONLY 4-5 DAYS OUT. WAA AHEAD OF THIS SYSTEM WOULD SUPPORT A VARIETY OF PRECIPITATION TYPES...DEPENDING WHETHER WE SEE PRECIP AT NIGHT OR IN THE DAYTIME. UNCERTAINTY COMPOUNDS AS WE GO FORWARD INTO THE EARLY TO MIDDLE PORTIONS OF NEXT WEEK AS THE UPPER LOW EVOLVES. THE LATEST GFS PRODUCES SPLIT FLOW DEVELOPING MONDAY NIGHT INTO TUESDAY...WITH THE BULK OF ASSOCIATED PRECIPITATION OFF TO OUR NORTH IN CANADA. THE LATEST 00Z ECMWF (MUCH SLOWER THAN THE 12Z ECMWF) MAINTAINS A CLOSED SYSTEM AND DOES IMPACT WEST AND NORTH CENTRAL PARTS OF THE STATE WITH WINTER WEATHER. ALL SOLUTIONS BRING IN MUCH COLDER AIR SOMETIME TUESDAY OR WEDNESDAY. WILL CONTINUE TO MONITOR IN THE COMING DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1004 AM CST WED NOV 27 2013 MVFR STRATUS WILL CONTINUE TO PUSH SOUTH...INITIALLY IMPACTING KISN AROUND 18Z...AND FINALLY KJMS AROUND 23Z. A FEW FLURRIES WILL ACCOMPANY THE LOW CLOUDS...MAINLY AT KMOT. W/SW WINDS WILL BECOME NORTHWEST THIS AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...JV LONG TERM...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1228 PM EST WED NOV 27 2013 .SYNOPSIS... WINTER STORM CONTINUES TO LIFT TO THE NORTHEAST WITH UPSLOPE SNOW TONIGHT. HIGH PRESSURE BUILDING IN ON THANKSGIVING DAY AND LINGERING FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... BULK OF PRECIPITATION STARTING TO SHIFT EASTWARD ACROSS THE CWA ALONG WITH WEAK BOUNDARY. EXPECTING A TRANSITION TO NORTHWEST UPSLOPE SNOW SHOWERS LATER THIS MORNING INTO EARLY AFTERNOON. COULD SEE ANOTHER INCH OR SO ACROSS PARTS OF THE WV LOWLANDS THIS AFTERNOON/EVENING PARTICULARLY IF A DECENT BAND IS ABLE TO SET UP ACROSS THE LAKES...WITH STILL SEVERAL INCHES POSSIBLE ACROSS THE HIGHER TERRAIN COUNTIES...PARTICULARLY ON WEST/NORTHWEST FACING SLOPES. FOR NOW...WILL LEAVE HEADLINES AS IS...SOME OF THE LOWLAND COUNTIES MAY BE ABLE TO BE CANCELLED EARLY...BUT WILL MONITOR FOR NOW. PREVIOUS DISCUSSION... GENERALLY FOLLOWING THE HRRR MODEL IN REGARDS TO THE EVOLUTION OF THE SYNOPTIC SNOW OVER THE NEXT FEW HOURS INTO THE DAWN HOURS. DEFORMATION ZONE PROVIDING THE MAIN FORCING OF THE SNOW AT THIS POINT WILL DRIFT TO THE EAST THROUGH 12Z TODAY...AND CARRY THE BETTER CHANCES FOR SNOW WITH IT. THERE WAS A PATCH OF DRIER AIR TO CONTEND WITH A FEW HOURS AGO DURING THE TEMPERATURE TRANSITION TO BELOW FREEZING VALUES...AND HAVE GOTTEN OFF TO A SLOW START IN TERMS OF ACCUMULATIONS. THIS SPARKS A FEW CONCERNS ABOUT MEETING THE PREVIOUSLY FORECASTED AMOUNTS...BUT WILL NOT GIVE UP ON IT JUST YET AS WE STILL HAVE A FEW HOURS TO GET SOME ACCUMULATIONS OUT OF THIS. AS THE MAIN SYNOPTIC FORCING FOR THIS EVENT DEPARTS WITH THE DEFORMATION ZONES PUSHING EAST OF THE MOUNTAINS AND THE 500MB TROUGH AXIS PASSING LATER TODAY...THE SET UP LOOKS FAIRLY DECENT TO HAVE CONVECTIVE SNOW FOR THE FIRST PART OF TODAY. LOOKING AT A CROSS SECTION ORIENTED TO THE MEAN LOW LEVEL WIND SHOWS GOOD SATURATION INTO THE CRYSTAL GROWTH LAYER...FED BY NORTHWEST FLOW THROUGH THE LOW LEVELS. FIGURE THE NATURE OF THE SNOW WILL BE OFF AND ON AT THIS POINT...BUT A QUICK INCH HERE AND THERE WILL BE POSSIBLE THROUGH 18Z OR 20Z TODAY FOR THE LOWLANDS. THIS POTENTIAL INCREASED IN THE MOUNTAINS IN THE BETTER UPSLOPE CONDITIONS. AFTER THAT...IT WILL MAINLY BE A MOUNTAIN EVENT ONLY THAT WILL SLOWLY FADE DURING THE OVERNIGHT PERIOD. WINDS WILL BE ON THE INCREASE OUT OF THE NORTHWEST TODAY...WITH GUSTS UP TO 30KTS AT TIMES. BLOWING SNOW OVER THE HIGHEST RIDGES IS LIKELY LATER TODAY AND TONIGHT. DID NOT GET CUTE WITH THE TEMPERATURES TODAY. MAX TEMPERATURES MAY BE RIGHT AT DAWN AS THE COLDER AIR COMES IN...AND THEN WILL CHILL A COUPLE DEGREES...BUT COULD MAKE A DEGREE OR TWO RECOVERY THROUGH THE AFTERNOON TOWARDS THE MORNING VALUES. IN THE END...HIGHS AROUND 30F WILL RULE FOR MUCH OF THE AREA...AND GETTING COLDER FOR THE MOUNTAINS BY EVENING. OVERNIGHT...HAVE SNOWSHOE IN THE SINGLE DIGITS...WITH OTHER LOCATIONS FALLING INTO THE TEENS TO LOWER 20S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... UPPER PATTERN ACROSS THE UNITED STATES RETURNS TO A ZONAL FLOW THROUGH THE EARLY WEEKEND. THIS WILL KEEP THE COLDEST AIR WITH CANADIAN HIGH PRESSURE CENTERS UP IN CANADA. EVEN THOUGH UPPER IMPULSES WILL TRACK EASTWARD THROUGH THE FLOW...THEY WILL BE WEAK. THIS..IN COMBINATION WITH GULF OF MEXICO MOISTURE BEING CONFINED ACROSS THE SOUTHERN STATES...WILL BRING DRY CONDITIONS AND A DAY TIME WARMING TREND. HIGH TEMPERATURES IN THE 30S THURSDAY WILL REACH WELL INTO THE 40S FRIDAY AND SATURDAY. HOWEVER...THE DRY AIR ALONG WITH LACK OF CLOUDS...WILL ALLOW FOR COLD NIGHT TIME READINGS WELL BELOW FREEZING. THUS...LOOK FOR DRY WEATHER AND A LARGE RANGE IN DIURNAL TEMPERATURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... A RATHER TRANQUIL ZONAL FLOW WITH SOME WEAK TROUGH APPROACHING LATE IN THE WEEKEND. WILL CONTINUE BRINGING BACK SOME CHANCE POPS FOR LIGHT RAIN SUNDAY NIGHT AND BECOMING MORE WIDESPREAD MONDAY BEFORE DIMINISHING POPS MONDAY NIGHT. NOT ANY STRONG FEATURES OR FRONTS EXPECTED DURING THIS PERIOD. NO BIG DEVIATIONS FROM HPC MEDIUM RANGE GROUP TEMPERATURES. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... 18Z WEDNESDAY THROUGH 18Z THURSDAY... WIDESPREAD MVFR AND LOCAL IFR CONDITIONS CONTINUE. LIGHT SNOW SHOWER ACTIVITY ACROSS SOUTHEAST OHIO...EASTERN KY...AND WV LOWLANDS THROUGH MAINLY 06Z THURSDAY...WITH CONTINUED UPSLOPE SNOW SHOWERS THROUGH 15Z THURSDAY ACROSS HIGHER TERRAIN COUNTIES. EXPECT GRADUAL LIFTING/CLEARING TO VFR ACROSS LOWLANDS AFTER 03Z- 06Z AND ACROSS HIGHER TERRAIN COUNTIES AFTER 12Z. OTHERWISE...GUSTY NORTHWESTERLY WINDS...WITH GUSTS OF UP TO 26 KTS ACROSS THE LOWLANDS THROUGH 05Z...AND UP TO 40 KTS ACROSS HIGHER TERRAIN AREAS THROUGH 12Z THURSDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: VSBY AND CEILING CATEGORIES COULD VARY FROM FORECAST. LIFTING TO VFR MAY NOT OCCUR AS SOON AS FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY L L H H H H H M L L L H HTS CONSISTENCY L H H H H H H H H H H H BKW CONSISTENCY M L L L L L L L L L L L EKN CONSISTENCY L L L L L L L L L L L L PKB CONSISTENCY H H H H H M M M H H M H CKB CONSISTENCY L L L H L L L L L L L L AFTER 18Z THURSDAY... NO WIDESPREAD IFR EXPECTED AFTER 12Z THURSDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR WVZ035>037. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ008>011-013>020-024>034-039-040. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR WVZ038-046- 047. OH...NONE. KY...NONE. VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...SL/26 SHORT TERM...JMV LONG TERM...KTB AVIATION...SL
AREA FORECAST DISCUSSION
NWS SPOKANE WA
224 PM PST Wed Nov 27 2013 .SYNOPSIS... Little change in the weather is expected through Friday, but big changes are coming this weekend and continuing into next week. This air-mass change will bring gusty winds, increased chances for precipitation and much, much colder temperatures. && .DISCUSSION... Tonight and Thanksgiving Day...A stale and persistent weather pattern will continue through the next 24 hours. Aloft...the deep trough off the coast will pinch off into a closed low far to the south...promoting a transition to westerly flow aloft over the forecast area...but this high altitude flow transition will do nothing to impact the boundary layer which will remain locked under an inversion lid. Thus...forecast for tonight will resemble what occurred last night...and the forecast for tomorrow will resemble what happened today...and yesterday...and the day before. Morning fog and stratus in valley locations...eventual break out into partly sunny conditions...cool temperatures and light winds. After coordination with air quality authorities it was decided to extend the Air Stagnation Advisory until Saturday afternoon when confidence is increasing for an erosion of the stubborn inversion. /Fugazzi Thursday night to Saturday night: Precipitation chances increase as the upper ridge breakdown continues and a strong system starts to drop along the B.C. coast. Through the period the Inland Northwest remains in west-northwest flow. The jet axis remains just north of the region. Two upper disturbances slip by ahead of that developing system. These will bring some precipitation chances. The first threat comes to the Cascades and Canadian border Thursday night. The threat expands throughout all but the deeper Columbia Basin between Friday and Saturday, as isentropic ascent strengthens and moisture deepens. Based on condensation pressure deficits (CPD), the best moisture and highest precipitation comes to the northern mountain by early Friday, then expands across the eastern third of WA and the central ID Panhandle by late Friday afternoon and evening. It lingers here through Saturday and Saturday night. The threat of precipitation will only be enhanced Saturday night, especially near the Cascades at the strong system comes to our doorstep. Precipitation-type is expected to be mainly valley rain and mountain snow during the daylight hours. A mix may reach valley floors, especially across the north, at night. Overall precipitation amounts are expected to be light, owning to the fact high pressure lingers in the low levels and that lift is generally not too deep. A quick inch of snow is possible over the mountains late Friday/Friday night, especially toward the Panhandle and some accumulation is possible again starting Saturday night especially near the Cascades. However precise snow levels around the Cascades may just above pass level. Stay tuned. Surface high pressure will continue to limit mixing and allow stagnant air conditions to persist, at least until that stronger system approaches. I also kept some patchy fog in the forecast for Thursday night and Friday morning in areas which has seen in the past few days, including the sheltered northeast valleys and L-C Valley. /J. Cote` ...A VERY COLD WINTER STORM TO IMPACT THE REGION OVER THE HOLIDAY WEEKEND... Sunday through Wednesday: Models remain in strong agreement that a deep, cold low pressure system will drop into the region over the weekend. A 140-160kt northerly jet off the Western Canadian Coast will deliver the system to the Pac NW and continue to feed very cold air southward setting up what looks to be the coolest week we have experienced in some time. Initially (Sunday), A warm moisture conveyor belt of subtropical moisture ahead of the wave will bring mainly valley rain and mountain snow with a brief upward trend in snow levels. However, snow levels will quickly drop to valley floors behind a cold front Sunday night into Monday morning bringing the potential for valley snowfall. Cold conditions will remain in place through much of the week. * Model uncertainty: Several differences noted in the models yesterday or today continue to keep some uncertainty with the forecast. First off, the timing of the initial cold front is now more agreed upon and looks to favor the Euro`s Sunday night time-frame. What is still in question is the exact track of the upper-level low, the orientation of the jet streak rounding the base of the low, and where the low sets up. This is leading to large uncertainty with the wind gust potential and snow levels on Sunday then amount of valley snow Monday. Until these features can be determined, the forecast will continue to carry a modest amount of uncertainty. * Snow/Rain: Good agreement that moist isentropic ascent will bring widespread precipitation Sunday and Sunday night until the cold front passage. the exception is in the immediate lee of the Cascades where some shadowing will take place. We are fairly certain all valleys south of Hwy 2 to Spokane and south of I-90 will be rain or transition from wet snow to rain. Models suggest the Methow and Okanogan Valleys will also be rain but given the terrain resolution of the GFS/Euro, we are not sold completely yet. The Euro, which has more of a northwest jet streak...maintains enough cold air over far NE WA and Nrn ID to support snow levels around 2300-2500` between Sandpoint and Bonners Ferry while the GFS surges levels near 6000`. If it was to fall as snow, it could be the heavy wet variety. Aside from Snoqualmie Pass, all other passes will experience snow on Sunday and Sunday night but a mix with rain will be possible for a period of time at Stevens and Lookout, pending which model`s snow level verifies. The cold front will slide through Sunday night and should be into northern Oregon by Monday morning. Any precipitation from that point onward will be all snow no matter what elevation. If the Euro track was to pan out, several waves pivoting within the mean low will lead to valley snow for just about any location from the Cascades to the MT border. The GFS suite on the other hand would keep any valley snow confined mainly to the ID Panhandle and portions of SE WA. * Wind: Gusty south to southwest winds will develop Sunday within the warm sector. A low-level jet with winds of 45-60kts will bring strong gusts to the ridgetops but is not expected to mix to the valley floors. Following the orientation of the Euro`s jet which is nw to se across the Cascades, there is a potential for strong wind gusts in the form of breaking mountain waves. Otherwise, there is threat for a brief period of strong winds just about every location as the actual cold front pushes through. As the arctic air bleeds into the region, breezy to gusty north winds will setup down the narrow channels of the Okanogan Valley and spill into the Western Basin while northeast winds channel down the Purcell Trench into the Eastern Basin. Winds of 15 to 30 mph with gusts in excess of 40 mph will be possible with each of these gradient driven winds. * Temperatures: Temperatures will be quite mild for November`s standards Sunday with the region in the warm sector. These temperatures will come crashing down on Monday and continue to cool for Tuesday and Wednesday when the true arctic air arrives. 850mb temperatures will be cooling from 0 to +4 Sunday toward -6C on Monday toward -12C on Wednesday. This will equate to high temperatures from the 30`s and 40`s Sunday to 10`s and 20`s Tues/Wed. Lows will be much more of a wildcard without knowing if snow will be present on valley floors. The air mass itself would suggest single digits to teens but any new snow in the valleys could easily bring negative single or double digit readings to the table. /sb && .AVIATION... 18Z TAFS: Fg and stratus extending from Bonners Ferry to Spokane and along most rivers/lakes should begin breaking btwn 20-21z. Until then...LIFR/IFR cigs/vis will impact operations at GEG/SFF/COE/LWS. Once the low clouds break...VFR conditions can be expected with sct-bkn cigs btwn 10-20K AGL. High pressure remains in control aloft and should deliver a near persistent fcst tonight leading to fg and stratus redeveloping through the evening and overnight hours. Confidence is generally lowest regarding the timing of the fog breakup this morning and timing of redevelopment tonight. Fcst favored guidance from the HRRR with a nod to climatology. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 25 37 26 40 30 40 / 0 0 0 20 20 20 Coeur d`Alene 27 39 28 40 32 40 / 0 0 0 20 40 30 Pullman 27 45 28 42 32 43 / 0 0 0 10 30 20 Lewiston 27 40 29 45 34 46 / 0 0 0 10 20 20 Colville 24 37 26 38 28 39 / 0 0 0 30 30 40 Sandpoint 22 37 26 38 31 38 / 0 0 10 20 40 30 Kellogg 28 43 29 40 33 38 / 0 0 10 20 50 40 Moses Lake 19 38 22 42 27 43 / 0 0 0 10 10 10 Wenatchee 23 39 28 41 31 42 / 0 0 0 10 10 10 Omak 19 35 25 40 28 40 / 0 0 0 20 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 4 PM PST Saturday for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area-Northern Panhandle. WA...Air Stagnation Advisory until 4 PM PST Saturday for East Slopes Northern Cascades-Lower Garfield and Asotin Counties-Moses Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse- Waterville Plateau-Wenatchee Area. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1057 AM PST Wed Nov 27 2013 .SYNOPSIS... Little change in the weather is expected today and tomorrow, but big changes are coming this weekend and continuing into next week. This air-mass change will bring gusty winds, increased chances for precipitation and much, much colder temperatures. && .DISCUSSION... Rest of Today...No significant changes to the inherited forecast fro today`s weather...except to extend the longevity of fog and low clouds into the afternoon for the northern valleys and minor tweaks to expected high temperatures...only some stations and only a degree or two based on current observations and trends. The other issue is the Air Stagnation Advisory. After coordination with state and county air quality authorities it has been decided to extend the ASA until 4 pm Saturday given the weak likelihood that the precursor systems to Sunday`s big change will dent the inversion prior to at least Saturday. Otherwise...no significant weather issues with another day of cool and stale conditions. /Fugazzi && .AVIATION... 18Z TAFS: Fg and stratus extending from Bonners Ferry to Spokane and along most rivers/lakes should begin breaking btwn 20-21z. Until then...LIFR/IFR cigs/vis will impact operations at GEG/SFF/COE/LWS. Once the low clouds break...VFR conditions can be expected with sct-bkn cigs btwn 10-20K AGL. High pressure remains in control aloft and should deliver a near persistent fcst tonight leading to fg and stratus redeveloping through the evening and overnight hours. Confidence is generally lowest regarding the timing of the fog breakup this morning and timing of redevelopment tonight. Fcst favored guidance from the HRRR with a nod to climatology. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 37 25 39 26 40 30 / 0 0 0 0 0 20 Coeur d`Alene 39 25 40 27 41 31 / 0 0 0 0 0 30 Pullman 45 25 44 28 43 32 / 0 0 0 0 0 20 Lewiston 40 28 42 30 46 34 / 0 0 0 0 0 20 Colville 37 23 38 25 39 28 / 0 0 0 0 30 30 Sandpoint 37 22 38 25 39 30 / 0 0 0 10 20 30 Kellogg 43 26 43 29 39 32 / 0 0 0 10 10 40 Moses Lake 38 21 39 23 43 28 / 0 0 0 0 0 0 Wenatchee 39 26 39 28 41 30 / 0 0 0 0 0 0 Omak 35 21 36 24 40 28 / 0 0 0 0 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 4 PM PST Saturday for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area-Northern Panhandle. WA...Air Stagnation Advisory until 4 PM PST Saturday for East Slopes Northern Cascades-Lower Garfield and Asotin Counties-Moses Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse- Waterville Plateau-Wenatchee Area. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
915 AM PST Wed Nov 27 2013 .SYNOPSIS... Little change in the weather is expected today and tomorrow, but big changes are coming this weekend and continuing into next week. This air-mass change will bring gusty winds, increased chances for precipitation and much, much colder temperatures. && .DISCUSSION... Today...There really isn`t much more to say than what we have been saying the last several days. The ridge of high pressure that has anchored itself will continue to get nudged to the east. More of the same weather-wise today and tonight, but the first hints of a change will come on.... Thanksgiving Day...A shift from the dominant ridge of high pressure to a more westerly or west-northwesterly flow will commence late Thanksgiving day. A very minor shortwave will traverse the Inland Northwest Thursday afternoon. Much of the affects associated with this shortwave remain well north, and only minor pops were included for the northern Cascades. Weak mixing will continue, so we don`t expect much of an air-mass change....yet. This wave will be the beginning of a much more active pattern continuing into next week. ty Friday through Saturday...The high amplitude ridge which has blanketed the Inland Northwest for the past week will finally give way to a increasingly zonal or westerly flow pattern. This will transition our dry and cool air mass to a warmer and more moisture laden one. This transition will be accompanied by an increasing chance of precipitation, but the question is when will it arrive. Models in decent agreement that the first chances of precipitation will impact the northern third of the forecast area on Friday as a weak warm front brushes the Canadian Border. That means locations generally north of the Highway 2/I90 corridor will see a chance of light precipitation especially during the afternoon. Precipitation type is a little tricky as the models are generally insistent that wet bulb temperatures would support valley rain and mountain snow. However mixing potential is not great ahead of the warm front so it possible the valleys could hold onto snow or a rain/snow mix through the day. In either case, the precipitation amounts will be light so the impacts will be slight. Through Friday night...the front will continued to droop to the south...which should spread the precipitation chances across the remainder of the Inland Northwest. Again precipitation amounts will be light...but snow levels could remain tricky as warming above the ground will likely outpace the warming near the ground. By Saturday the warming will likely overcome any sub-freezing air trapped near the ground as a more robust 850 mb low tracks through central BC. This will enhance the mixing potential and increase the moisture even further. Precipitation chances will likely be at their highest during this period...but given the predominant westerly flow...most of the Basin will be skipped over. Meanwhile the Cascades should see relatively highs chances of measurable precipitation as will the Idaho Panhandle. Precipitation amounts will remain light. fx ...A VERY COLD WINTER STORM TO IMPACT THE REGION OVER THE HOLIDAY WEEKEND... Saturday night through Wednesday: The longwave pressure pattern will take a dramatic shift during this period. An upper level ridge of higher pressure will build over the eastern Pacific into Alaska as a strong upper level low pressure system carves its way down western Canada into the Northwest. Between these two upper level pressure systems will be a 160 kt northwest to southeast oriented jet directed toward Washington State. A moisture plume with P-wats of around 0.75 inches will ride this jet into the Inland Northwest. The low pressure system will also be accompanied by a strong cold front that will sag southward out of BC. This front will interact with this moisture off of the Pacific to produce a band of precip that sags from north to south beginning Saturday and continuing into Sunday. This is where models are in fairly good agreement. Models begin to diverge as the upper level low begins to enter the region out of BC. The 00Z ECMWF and Canadian model guidance shows the upper level low taking a more westerly track across western WA and is more consolidated as it does so. The 00Z and 06Z GFS model runs are more muddled with the track of the low. It is far less consolidated and has a more broad ahead of low pressure from western WA into central MT. The best dynamics off the GFS runs tracks further east into MT. Considering that the GFS has been less consistent and has generally been catching up to ECMWF and Canadian, I would not be surprised if the GFS trends more toward the ECMWF and Canadian solutions. If the ECMWF/Canadian solution pans out, then we will be looking at a better potential for heavier valley snowfall for Sunday night into Monday. * Precipitation: Strong warm air advection ahead of the cold front Saturday into Sunday will result in primarily valley rain and mountain snow. Strong westerly flow will also likely produce a noticeable rain shadow directly east of the Cascade Mtns. This will result in the heaviest precip occurring along the Cascade crest and in the ID Panhandle. Heavy mountain snow can be expected with snow levels starting out around 3,500 feet and increasing to up around 5,000 feet on Sunday. The exception will be across the northern mtns and vlys where colder air may hold out. A rain/snow mix will be possible across these northern valleys at onset, but should become all rain as snow levels surge up on Sunday. Cold arctic air will then funnel in Sunday night into Monday with snow level crashing to valley floors. This will be the best chance for valley snowfall, especially if the wetter more westward track of the upper level low verifies. * Winds: A strong low level jet is expected in the warm sector of this system on Sunday with 850 mb winds at around 40-50 kts. This will likely create breezy conditions across the basin, but the strongest winds will likely be reserved for the mountains; ridge top winds are expected to gust upwards of 50 mph. Better mixing potential will be possible with the cold front Sunday evening/night where some higher wind gusts will be possible. * Temperatures: Frigid temperatures are expected as cold arctic air pushes into the region from Canada. Temperatures will drop dramatically from Sunday into Monday with a 10-20 degree drop expected in high temperatures. Temperatures will only continue to get colder into early next week as the upper level low continues to dig across the western U.S. Low temperatures will have the potential to dip into the single digits. Some negative temperatures will be possible by Tuesday night and Wednesday night. Northerly winds down the Okanogan Valley and through the Purcell Trench may also result in some very cold wind chill values, especially Monday night through Tuesday night. /SVH && .AVIATION... 18Z TAFS: Fg and stratus extending from Bonners Ferry to Spokane and along most rivers/lakes should begin breaking btwn 20-21z. Until then...VIFR/IFR cigs/vis will impact operations at GEG/SFF/COE/LWS. Once the low clouds break...VFR conditions can be expected with sct-bkn cigs btwn 10-20K AGL. High pressure remains in control aloft and should deliver a near persistent fcst tonight leading to fg and stratus redeveloping through the evening and overnight hours. Confidence is generally lowest regarding the timing of the fog breakup this morning and timing of redevelopment tonight. Fcst favored guidance from the HRRR with a nod to climatology. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 38 25 39 26 40 30 / 0 0 0 0 0 20 Coeur d`Alene 40 25 40 27 41 31 / 0 0 0 0 0 30 Pullman 44 25 44 28 43 32 / 0 0 0 0 0 20 Lewiston 40 28 42 30 46 34 / 0 0 0 0 0 20 Colville 37 23 38 25 39 28 / 0 0 0 0 30 30 Sandpoint 37 22 38 25 39 30 / 0 0 0 10 20 30 Kellogg 43 26 43 29 39 32 / 0 0 0 10 10 40 Moses Lake 38 21 39 23 43 28 / 0 0 0 0 0 0 Wenatchee 38 26 39 28 41 30 / 0 0 0 0 0 0 Omak 35 21 36 24 40 28 / 0 0 0 0 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 10 AM PST Friday for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area-Northern Panhandle. WA...Air Stagnation Advisory until 10 AM PST Friday for East Slopes Northern Cascades-Lower Garfield and Asotin Counties-Moses Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse- Waterville Plateau-Wenatchee Area. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 PM CST WED NOV 27 2013 .SHORT TERM...(THIS EVENING THROUGH THANKSGIVING) ISSUED AT 310 PM CST WED NOV 27 2013 OVERALL A QUIET WEATHER PERIOD THROUGH THE WEEKEND...AFTER SOME LIGHT SNOW ACROSS THE NORTH TONIGHT. HAVE BEEN MONITORING SHORTWAVE TROUGH 1 MOVING INTO MINNESOTA THIS AFTERNOON WITH LIGHT SNOW IN THE 1-2SM VISIBILITY RANGE...WITH A BIT LOWER FURTHER NORTHWEST ALONG THE MN/CANADA BORDER. ECHO IS INCREASING IN NW WI...BUT THE PRECIPITATION IS WORKING ON SATURATION AND NOT MAKING IT TO THE SURFACE. THE UPPER TROPOSPHERIC SHORTWAVE TROUGH IS LOCATED IN NWRN MN AT 20Z PER GOES WATER VAPOR IMAGERY...WITH SHORTWAVE TROUGH 2 ON ITS HEALS JUST NORTHWEST OF LAKE WINNIPEG. MORNING RAOB AT KMPX WAS DEEPLY DRY BUT THE FORCING WITH THE SHORTWAVE TROUGH IS WORKING PRETTY RAPIDLY TO SATURATE THE COLUMN AND PRODUCE SNOW....ON THE ORDER OF A COUPLE HOURS. PER THE LATEST RAP...THIS FORCING IS A CONTRIBUTION FROM WARM ADVECTION IN THE LOW LEVELS / AND 700MB FRONTOGENESIS/ AND MID-UPPER LEVEL QG CONVERGENCE. THE FIRST SHORTWAVE WILL TRACK TOWARD THE NORTHERN FORECAST AREA THIS AFTERNOON AND ARRIVE AROUND 6-7 PM IN CLARK AND TAYLOR COUNTIES PER RAP FORECASTS AND TRACKING. THIS FIRST SHORTWAVE TROUGH WEAKENS AS IT MOVES IN PER THE CONSENSUS MODEL GUIDANCE AS THE SECOND WAVE INTENSIFIES AND DEEPENS. HOWEVER...THERE IS GUIDANCE /HRRR/ SOLUTIONS DIMINISHING THE WEATHER AS IT MOVES SOUTHEAST AND DRY AIR IN PLACE WILL DOMINATE. WITH CONSENSUS FORCING SWIPING A BAND OF SNOW IN THE EVENING AND CURRENT CONDITIONS...HAVE FORECAST THE SNOW TO MOVE IN DURING THE EVENING AND ACCUMULATE...MAINLY I-94 AND NORTH. THIS IS NOT A BIG CHANGE TO ONGOING FORECAST..BUT HIGHER CONFIDENCE. WILL LIKELY HIT THIS A BIT IN THE SOCIAL MEDIA AND SPECIAL WEATHER STATEMENTS WITH MORE TRAVEL THIS EVENING HAPPENING. SOME DIFFICULTY IN TRYING TO FIGURE OUT THE REMAINDER OF THE NIGHT AFTER MIDNIGHT...AHEAD OF THE SECOND SHORT WAVE TROUGH. IT APPEARS THE FRONTOGENESIS NEAR 700MB WILL BE STRONGER THAN THE FIRST SHORTWAVE AND WITH THE UPPER QG FORCING MAINLY OVER NRN WI /MODEL CONSENSUS/...SNOW SEEMS TO BE A GIVEN. BUT AS SHORTWAVE TROUGH 2 DEEPENS...THE FORCING SHIFTS INTO NORTHERN WI AND MAY SPREAD ITS SNOW NORTH OF TAYLOR COUNTY. FEEL FAIRLY CONFIDENT SNOW WILL OCCUR OVERNIGHT...BUT HAVE DECIDED TO MOVE IT NORTH WITH TIME AND LEAVE FLURRIES SOUTH TO I-94. THE SNOW RATIOS COULD BE QUITE HIGH WITH THIS SNOW WITH MOST OF THE SATURATED COLUMN IN THE DENDRITE GROWTH ZONE -12 TO -18C...THUS LOW QPF COULD PRODUCE AN INCH PRETTY EASY. MAINLY FLURRIES SHOULD REMAIN DURING THE EARLY MORNING THURSDAY WITH ROADS CLEANING UP FOR TRAVEL. SUN IS EXPECTED BY AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 310 PM CST WED NOV 27 2013 A PERIOD OF QUIET WEATHER WITH SOME MODERATION IN TEMPERATURES BEGINNING FRIDAY...BUT A COLD START THAT MORNING UNDER HIGH PRESSURE AND CLEAR SKIES. IF A BIT MORE SNOW FALLS IN TAYLOR COUNTY TONIGHT ACROSS TAYLOR COUNTY...FRIDAY MORNING COULD BE NEAR ZERO. NEXT WEATHER SYSTEM SHIFTS ACROSS NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY WITH THE MORE FAVORABLE FORCING NORTH OF THE AREA. MAYBE SOME CLOUDS AND FLURRIES IN TAYLOR COUNTY BUT HAVE KEPT DRY FORECAST INTACT. SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE IN THIS PERIOD AS THE MODEL GUIDANCE HAS DIFFERENT EVOLUTIONS AND TIMING TO THE MAJOR READJUSTMENT OF THE LARGE SCALE PATTERN OVER NORTH AMERICA. MAJOR TROUGH AND COLD POOL OF AIR INVADE THE WESTERN CONUS WITH AN ASTOUNDING -3.5 TO -4 STANDARD DEVIATION BELOW NORMAL 850 MB TEMP IN THE WESTERN CONUS. BECAUSE OF THE SPREAD IN THE MODELS AND HOW ENERGY EJECTS OUT OF THE TROUGH...THE FORECAST HAS SMALL PRECIPITATION CHANCES MONDAY TO WEDNESDAY. THIS COULD BE A DRY PERIOD SHOULD THE 27.12Z ECMWF SOLUTION OCCUR...WHICH THE 27.12Z GFS TRENDED TOWARD...WITH MORE WEATHER LATER IN THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1137 AM CST WED NOV 27 2013 AN 8 TO 10K DECK AHEAD ON APPROACHING SHORT WAVE TROUGH WILL MOVE INTO KRST AROUND 27.20Z AND KLSE AROUND 27.21Z. AS THE 285K ISENTROPIC LIFT AND WARM AIR ADVECTION INCREASES AHEAD OF THIS WAVE...THE CEILINGS WILL DESCEND INTO THE 3 TO 5K RANGE AFTER 28.03Z AND THEN REMAIN THERE THROUGH 28.12Z AT KRST AND 28.14Z AT KLSE. SUBSIDENCE BEHIND A SECOND SHORT WAVE TROUGH WILL THEN CLEAR SKIES ACROSS THE AREA. THERE APPEARS TO BE A SMALL WINDOW FOR SOME VERY LIGHT SNOW AT KLSE BETWEEN 28.06Z AND 28.08Z. VISIBILITIES SHOULD REMAIN ABOVE 6SM. WINDS WILL BE BETWEEN 4 AND 8 KNOTS. THEY WILL BECOME SOUTHERLY THIS AFTERNOON AND THEN SHIFT TO NORTHWEST BETWEEN 28.12Z AND 28.16Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM...BAUMGARDT AVIATION...BOYNE