Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/08/13


AREA FORECAST DISCUSSION
NWS NEW YORK NY
1251 PM EST FRI DEC 6 2013 .SYNOPSIS... LOW PRESSURE MOVES EAST ALONG A STALLED FRONT TO OUR SOUTH OVERNIGHT. COLD HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW PRESSURE APPROACHES SUNDAY NIGHT AND IMPACTS THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK WITH HIGH PRESSURE BUILDING IN FOR THE SECOND HALF. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND. SFC COLD FRONT SEEN ON RADAR AND IN THE OBS APPROACHING OCEAN CITY AS OF 1630Z. LATEST HRRR AND RADAR CONTINUES TO SUPPORTS LIGHT RA ENDING FOR A BRIEF PERIOD EARLY THIS AFTERNOON FROM WEST TO EAST THEN REDEVELOPING THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE RIDE ALONG THE FRONT. TEMPS STEADY UNTIL 3-4 PM...THEN START A SLOW FALL IN THE COLD ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... HAVE ISSUED A WINTER WX ADVISORY FOR ORANGE AND PUTNAM COUNTIES FOR TONIGHT BASED ON LASTED DATA AND COLLABORATION WITH SURROUNDING NWS OFFICES. COLD "NOSE" IN LOW LEVELS AROUND 2-4K FT AGL LAYER WITH TEMPS OF -3 TO -5 C BY 00Z AT KSWF SEEN IN 12Z NAM SOUNDING. THIS CLEARLY SUPPORTS SLEET. IN FACT, MODERATE TO OCCASIONALLY HEAVY SLEET. SLEET ACCUMULATION IN ORANGE MY BE AN INCH OR MORE. ITS TOWARDS 10 TO 11 PM THAT THE COLUMN ALOFT (5-10K FT AGL) COOLS ENOUGH TO SUPPORT SNOW. SNOW AMOUNTS ON TOP THE SLEET WILL DEPEND ON THE PRECISE TIMING OF THIS COOLING ALOFT. SEE THE POTENTIAL, BASED ON SREF PLUMES, FOR SEVERAL INCHES. THINKING THE HIGH END WOULD BE 5 WITH MORE LIKELY THE 1 TO 3 RANGE. HAVE ISSUED THE WSW BASED ON THE EXPECTED SIGNIFICANT AMOUNT OF SLEET AT THE START EVEN THROUGH COUNTY AVERAGES ARE BELOW THE 3 INCH CRITERIA. IN ADDITION...TEMPS BELOW FREEZING IN THE ADVISORY AREA WILL MAKE FOR A SIGNIFICANT IMPACT ON TRAVEL. WITH THE LOSS OF COLD CLOUD SEEDER/FEEDER NUCLEATION...PCPN IN THE ADVISORY AREA MY END AS LIGHT FREEZING DRIZZLE. THE I-84 CORRIDOR IN CT SHOULD ALSO GET ACCUMULATIONS. THUS THESE AREAS ARE IN THE HWO PRODUCT AND WILL ISSUE AN SPECIAL WEATHER STATEMENT ONCE RULES ALLOW. ALONG THE COAST...SEE ALL RAIN. THINK THE POTENTIAL FOR AN SLEET IS TOO LOW TO MENTION. EXPECT PCPN TO END QUICKLY SATURDAY AM WITH CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. TEMPS RISE TO THE UPPER 30S TO LOWER 40S SATURDAY (GFS MOS USED)...WHICH IS SLIGHTLY BELOW NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS. FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST AROUND OR SHORTLY AFTER MIDNIGHT. FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT. DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH THAT WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD THEN FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN WOULD THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED BY A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN AND WARMING TEMPS. THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... MVFR WITH LCL IFR CONDS THIS AFTERNOON IN -RA/BR. LOW PRES APPROACHES TONIGHT. ALL RAIN AT THE TERMINALS THROUGH 10Z...POSSIBLY MIXING WITH SLEET AS PRECIP WINDS DOWN AROUND 10Z. FOR KSWF...RAIN CHANGES TO SLEET THIS EVENING...AND THEN SNOW/SLEET ON TAP FOR MUCH OF TONIGHT BEFORE PRECIP TAPERS OFF AS SNOW LATE. IFR/LIFR CONDS. N WINDS AROUND 10 KT...BACKING TO THE NW SATURDAY MORNING. VFR BY LATE SATURDAY MORNING. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: MARGINAL CONDS...LOWERING TO IFR BY 23Z. KJFK FCSTER COMMENTS: MARGINAL CONDS...LOWERING TO IFR BY 23Z. KLGA FCSTER COMMENTS: MARGINAL CONDS...LOWERING TO IFR BY 23Z. KTEB FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 23Z. KHPN FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 23Z. KISP FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 00Z. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... .SAT AFTERNOON...VFR. NW WINDS 10-20 KT. .SUNDAY...VFR. LIGHT WINDS. .SUNDAY NIGHT...IFR. SNOW...THEN SNOW/SLEET/RAIN NEAR THE COAST AND SNOW/SLEET ACROSS INTERIOR. .MONDAY...IFR. RAIN. WINTRY MIX ACROSS INTERIOR EARLY...THEN RAIN. SE WINDS 10-15 KT...BCMG NW LATE. .MONDAY NIGHT...WINTRY MIX POSSIBLE. WEST WINDS 10 KT OR LESS. .TUESDAY...VFR. WEST WINDS 10 KT OR LESS. .WEDNESDAY...VFR. W WIND 15-25 KT. && .MARINE... COLD FRONT NOW WELL SOUTH OF THE OCEAN COASTAL WATERS. OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A WHILE TO SUBSIDE. OVERNIGHT...WINDS INCREASE FOR A SHORT TIME LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE SOUTH. WAVES ON THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS. SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED WITH THIS STORM. && .HYDROLOGY... PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL NEAR AN INCH. NO HYDROLOGIC ISSUES ANTICIPATED. A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST SATURDAY FOR NYZ067-068. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...TONGUE NEAR TERM...TONGUE SHORT TERM...TONGUE/PW LONG TERM...JC AVIATION...MPS MARINE...JC/PW HYDROLOGY...JC/PW EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1200 PM EST FRI DEC 6 2013 .SYNOPSIS... LOW PRESSURE MOVES EAST ALONG A STALLED FRONT TO OUR SOUTH OVERNIGHT. COLD HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW PRESSURE APPROACHES SUNDAY NIGHT AND IMPACTS THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK WITH HIGH PRESSURE BUILDING IN FOR THE SECOND HALF. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND. SFC COLD FRONT SEEN ON RADAR AND IN THE OBS APPROACHING OCEAN CITY AS OF 1630Z. LATEST HRRR AND RADAR CONTINUES TO SUPPORTS LIGHT RA ENDING FOR A BRIEF PERIOD EARLY THIS AFTERNOON FROM WEST TO EAST THEN REDEVELOPING THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE RIDE ALONG THE FRONT. TEMPS STEADY UNTIL 3-4 PM...THEN START A SLOW FALL IN THE COLD ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... HAVE ISSUED A WINTER WX ADVISORY FOR ORANGE AND PUTNAM COUNTIES FOR TONIGHT BASED ON LASTED DATA AND COLLABORATION WITH SURROUNDING NWS OFFICES. COLD "NOSE" IN LOW LEVELS AROUND 2-4K FT AGL LAYER WITH TEMPS OF -3 TO -5 C BY 00Z AT KSWF SEEN IN 12Z NAM SOUNDING. THIS CLEARLY SUPPORTS SLEET. IN FACT, MODERATE TO OCCASIONALLY HEAVY SLEET. SLEET ACCUMULATION IN ORANGE MY BE AN INCH OR MORE. ITS TOWARDS 10 TO 11 PM THAT THE COLUMN ALOFT (5-10K FT AGL) COOLS ENOUGH TO SUPPORT SNOW. SNOW AMOUNTS ON TOP THE SLEET WILL DEPEND ON THE PRECISE TIMING OF THIS COOLING ALOFT. SEE THE POTENTIAL, BASED ON SREF PLUMES, FOR SEVERAL INCHES. THINKING THE HIGH END WOULD BE 5 WITH MORE LIKELY THE 1 TO 3 RANGE. HAVE ISSUED THE WSW BASED ON THE EXPECTED SIGNIFICANT AMOUNT OF SLEET AT THE START EVEN THROUGH COUNTY AVERAGES ARE BELOW THE 3 INCH CRITERIA. IN ADDITION...TEMPS BELOW FREEZING IN THE ADVISORY AREA WILL MAKE FOR A SIGNIFICANT IMPACT ON TRAVEL. WITH THE LOSS OF COLD CLOUD SEEDER/FEEDER NUCLEATION...PCPN IN THE ADVISORY AREA MY END AS LIGHT FREEZING DRIZZLE. THE I-84 CORRIDOR IN CT SHOULD ALSO GET ACCUMULATIONS. THUS THESE AREAS ARE IN THE HWO PRODUCT AND WILL ISSUE AN SPECIAL WEATHER STATEMENT ONCE RULES ALLOW. ALONG THE COAST...SEE ALL RAIN. THINK THE POTENTIAL FOR AN SLEET IS TOO LOW TO MENTION. EXPECT PCPN TO END QUICKLY SATURDAY AM WITH CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. TEMPS RISE TO THE UPPER 30S TO LOWER 40S SATURDAY (GFS MOS USED)...WHICH IS SLIGHTLY BELOW NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS. FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST AROUND OR SHORTLY AFTER MIDNIGHT. FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT. DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH THAT WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD THEN FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN WOULD THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED BY A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN AND WARMING TEMPS. THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... COLD FRONT NOW WELL SOUTHEAST OF LONG ISLAND. MARGINAL CIGS THIS AFTERNOON WITH RA. IFR TNGT WITH RAIN. GRADUAL MIXING WITH SLEET AND SNOW FROM NW TO SE. ALL RAIN AT THE CITY TERMINALS THRU 6Z...WITH SOME MIXING POSSIBLE BY 12Z. PROB IS TO LOW ATTM TO INCLUDE IN THE TAFS. LGT SLY FLOW AHEAD OF THE FRONT...WITH WINDS NW BEHIND. GUSTS UP TO 20KT. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KLGA FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KTEB FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KHPN FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KISP FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 17Z. .OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... .SAT...BECOMING VFR BY AFTN. NW WIND 10-20KT. .SUN...VFR. LGT WIND. .SUN NGT...MVFR OR LOWER. SNOW/SLEET/FZRA INTERIOR. SNOW/SLEET/RAIN COAST. .MON...IFR. RA. SE WND 15-25KT BECOMING SW IN AFTN. .TUE...VFR. W WIND 15-25KT. && .MARINE... COLD FRONT NOW WELL SOUTH OF THE OCEAN COASTAL WATERS. OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A WHILE TO SUBSIDE. OVERNIGHT...WINDS INCREASE FOR A SHORT TIME LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE SOUTH. WAVES ON THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS. SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED WITH THIS STORM. && .HYDROLOGY... PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL NEAR AN INCH. NO HYDROLOGIC ISSUES ANTICIPATED. A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST SATURDAY FOR NYZ067-068. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...TONGUE NEAR TERM...TONGUE SHORT TERM...TONGUE/PW LONG TERM...JC AVIATION...MPS MARINE...JC/PW HYDROLOGY...JC/PW EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
950 AM EST FRI DEC 6 2013 .SYNOPSIS... A COLD FRONT CROSSES THE REGION EARLY TODAY. LOW PRESSURE RIDES THE STALLED FRONT TONIGHT WITH HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW PRESSURE RETURNS SUNDAY NIGHT AND IMPACTS THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE BUILDS IN FOR THE SECOND HALF. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND. SFC COLD FRONT SEEN ON RADAR AND IN THE OBS OFF SOUTH OF LONG ISLAND AS OF 1430Z. LATEST HRRR AND RADAR SUPPORTS LIGHT RA ENDING FROM WEST TO EAST FOR THE LUNCH HOUR AND THEN REFORMING THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE RIDE ALONG THE FRONT. TEMPS FALLING IN THE COLD ADVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... CURRENTLY EVALUATING NEEDS FOR WINTER WX ADVISORY FOR ORANGE AND PUTNAM COUNTIES. HOPE TO HAVE A DECISION BY 11 AM. UPPER SW FLOW PREVAILS THIS TIME FRAME. COLD FRONT SAGS FURTHER SOUTH IN TIME...AS RIDGE OF HIGH PRESSURE BUILDS FROM THE WEST. FOR TONIGHT...COLDER AIR CONTINUES TO FILTER IN FROM THE NORTH. RAIN WILL BECOME WIDESPREAD OVER THE AREA...TO THE NORTH OF THE WAVE OF LOW PRESSURE. A TRANSITION FROM RAIN TO SNOW/SLEET WILL OCCUR FROM NORTH TO SOUTH AS THE NIGHT PROGRESSES. AT THIS TIME...ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESS PROFILES WOULD SUGGEST RAIN AND SLEET IN THE EVENING OVER THE NW ZONES WILL TRANSITION TO SNOW/SLEET IN TIME. MAINLY RAIN NEAR THE COAST TONIGHT...WITH PERHAPS SOME SLEET MIXING IN FROM TIME TO TIME...ESPECIALLY AFTER MIDNIGHT. DO NOT FORESEE MUCH IN THE WAY OF FREEZING RAIN AND THUS SIGNIFICANT ICING BEHIND THE FRONT. AS SUCH...NO WINTER HEADLINES ARE PLANNED AT THIS TIME. MINOR SNOW ACCUMS THOUGH ARE EXPECTED ACROSS THE INTERIOR BY SAT MORNING. ORANGE COUNTY COULD SEE AN INCH OR TWO OF SNOW...ALONG WITH SOME SLEET ACCUM. CLOUDS IN THE MORNING GIVE WAY TO AFTERNOON SUNSHINE. CHILLY TEMPS RANGING FROM AROUND 30 INLAND TO THE MIDDLE 30S NEAR THE COAST LATE TONIGHT ARE ANTICIPATED. THEN TEMPS RISE TO THE UPPER 30S TO LOWER 40S SATURDAY...WHICH IS SLIGHTLY BELOW NORMAL. A MET/MAV MOS BLEND FOLLOWED. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS. FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST AROUND OR SHORTLY AFTER MIDNIGHT. FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT. DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH THAT WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD THEN FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN WOULD THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED BY A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN AND WARMING TEMPS. THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... COLD FRONT NOW EAST OF THE TERMINALS CONTINUES TO DEPART. BRIEF PERIOD OF IFR CIGS THROUGH 15-16Z...OTHERWISE...CIGS RANGING FROM 2500-3500 FT. LINGERING RAIN MOVING THROUGH THE REGION WILL GENERALLY RESULT IN MVFR VSBY AT WORST. IFR TNGT WITH RAIN. GRADUAL MIXING WITH SLEET AND SNOW FROM NW TO SE. ALL RAIN AT THE CITY TERMINALS THRU 6Z...WITH SOME MIXING POSSIBLE BY 12Z. PROB IS TO LOW ATTM TO INCLUDE IN THE TAFS. LGT SLY FLOW AHEAD OF THE FRONT...WITH WINDS NW BEHIND. GUSTS UP TO 20KT. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KLGA FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KTEB FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KHPN FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z. KISP FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 17Z. .OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... .SAT...BECOMING VFR BY AFTN. NW WIND 10-20KT. .SUN...VFR. LGT WIND. .SUN NGT...MVFR OR LOWER. SNOW/SLEET/FZRA INTERIOR. SNOW/SLEET/RAIN COAST. .MON...IFR. RA. SE WND 15-25KT BECOMING SW IN AFTN. .TUE...VFR. W WIND 15-25KT. && .MARINE... THE COLD FRONT MOVE SOUTH OF THE OCEAN COASTAL WATERS. OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A WHILE TO SUBSIDE. OVERNIGHT...WINDS MAY INCREASE SLIGHTLY FOR A SHORT TIME LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE SOUTH. WAVES ON THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS. SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED WITH THIS STORM. && .HYDROLOGY... PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL AROUND AN INCH...WITH MOSTLY RAIN EXPECTED. FLOODING IS NOT EXPECTED. A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...JC/PW NEAR TERM...TONGUE/PW SHORT TERM...TONGUE/PW LONG TERM...JC AVIATION...JMC MARINE...JC/PW HYDROLOGY...JC/PW EQUIPMENT...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1144 PM EST THU DEC 5 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 1258 PM EST THU DEC 5 2013 AN ACTIVE WEATHER PATTERN IS EXPECTED THE NEXT 24 HOURS AS WINTRY WEATHER RETURNS TO CENTRAL INDIANA. A COLD FRONT HAS PUSHED SOUTHEAST OF CENTRAL INDIANA...ALLOWING MUCH COLDER AIR TO PUSH IN TO THE AREA. A FLOW OF MOIST AIR ALOFT ALONG WITH SEVERAL UPPER LEVEL WEATHER DISTURBANCES ARE EXPECTED TO PUSH IN TO CENTRAL INDIANA TONIGHT AND AGAIN ON FRIDAY. THIS WILL RESULT IN ACCUMULATING SNOW TONIGHT AND FRIDAY FOR MOST OF CENTRAL INDIANA...AND THE FIRST REAL BIG SNOW OF THE SEASON. HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA FRIDAY NIGHT...ENDING THE SNOW. HOWEVER VERY COLD...ARCTIC AIR WILL ARRIVE IN INDIANA...WITH TEMPERATURES WELL BELOW NORMAL THOUGH THE WEEKEND. ANOTHER PASSING STORM SYSTEM MAY BRING SOME LIGHT SNOW OR FREEZING PRECIPITATION TO AREA ON SUNDAY THROUGH MONDAY. YET ANOTHER SHOT OF ARCTIC AIR IS THEN EXPECTED TO ARRIVE ON FOR THE MIDDLE OF NEXT WEEK AND HIGH TEMPERATURES WILL ONLY BE IN THE TEENS. && .NEAR TERM /TONIGHT/... ISSUED AT 951 PM EST THU DEC 5 2013 NAM12 AND RUC13 MODEL SOUNDINGS AND OBSERVATIONAL TRENDS SUGGEST PRECIPITATION TYPE WILL MAINLY BE SNOW THE REST OF THE NIGHT WITH THE EXCEPTION OF THE FAR SOUTH...WHERE SOME SLEET IS POSSIBLE THROUGH MIDNIGHT. LOOKING AT RAPID REFRESH REFLECTIVITY PROGS AND WITH SHARP DEEP MOISTURE GRADIENT...SOME CONCERN NORTHWEST COUNTIES WILL NOT SEE MUCH ACCUMULATION TONIGHT...BUT HATE TO PULL POPS AND ACCUMULATION TOO SOON...SO FOR NOW WILL STICK WITH IT. UPDATED GRIDS...HAZARDOUS WEATHER OUTLOOK AND WEATHER STORY WITH NEW WEB STORM BRIEFING TO COME. PREVIOUS DISCUSSION FOLLOWS... RADAR THIS AFTERNOON SHOWS A SURGE OF MOISTURE OVER SOUTHERN ILLINOIS STREAMING NORTHEAST TOWARD CENTRAL INDIANA. SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS COLD HIGH PRESSURE IN PLACE ACROSS THE CENTRAL PLAINS AND A COLD FRONT EAST OF INDIANA...OVER CENTRAL OHIO...EASTERN KENTUCKY AND CENTRAL TENNESSEE. COLD WEST TO NORTHWEST SURFACE FLOW WAS IN PLACE ACROSS CENTRAL INDIANA. SURFACE TEMPS WERE FALLING THIS AFTERNOON ACROSS THE NORTHWEST PARTS OF THE STATE AND BARELY RISING ACROSS SOUTH. THE WATER VAPOR IMAGERY IS IMPORTANT TODAY. IT SHOWS A PLUME OF MOISTURE STREAMING ACROSS MEXICO INTO THE AMERICAN SOUTHWEST AND THEN NORTHEAST INTO THE GREAT LAKES AND OHIO VALLEY. THIS STREAM OF MOISTURE WILL BE OUR SOURCE FOR PRECIP OVER THE NEXT 24-36 HOURS. FORECAST SOUNDINGS ACROSS THE AREA LEAN TOWARD A FREEZING RAIN PRECIP TYPE LATE THIS AFTERNOON AND THIS EVENING ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. PRECIPITABLE WATER VALUES AROUND 0.8 INDICATE PLENTY OF MOISTURE AVAILABLE FOR THIS SYSTEM. COLDER AIR IS EXPECTED TO ARRIVE ACROSS THE ENTIRE FORECAST AREA AFTER 06Z AS ALL FORECAST SOUNDINGS FALL BELOW FREEZING...CHANGING THE PRECIP TYPE TO ALL SNOW REGION WIDE. THUS HAVE TRENDED FORECASTS TOWARD 100 POPS...WITH BEST CHANCES FOR FREEZING PRECIP ACROSS SOUTHERN PARTS OF THE FORECAST AREA THIS EVENING. ALSO GIVEN THE EXPECTED PATH OF THE BAND OF MOISTURE...SOUTHERN INDIANA IS IN THE MOST FAVORABLE POSITION FOR HEAVIER SNOW AMOUNTS. AS FOR TEMPS...GIVEN THE COLD AIR ADVECTION BUT EXPECTED PRECIPITATION...HAVE TRENDED LOWS AT OR ABOVE MAVMOS. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... ISSUED AT 1258 PM EST THU DEC 5 2013 SNOW IS EXPECTED ON FRIDAY. FORECAST SOUNDINGS AND TIME HEIGHT SECTIONS CONTINUE TO SUGGEST A SATURATED COLUMN THROUGH THE DAY WITH SOUNDINGS ENTIRELY BELOW FREEZING. FLOW ALOFT CONTINUES TO SUGGEST THE MOIST SOUTHERN JET OF MOISTURE STREAMING IN TO THE OHIO VALLEY. EMBEDDED SHORT WAVE ARE EXPECTED TO PROVIDE MORE FORCING FOR ONGOING SNOW. TIME HEIGHT SECTIONS SHOW ANOTHER ROUND OF GOOD VV DURING THE AFTERNOON HOURS. PRECIPITABLE WATER VIA FORECAST SOUNDINGS SHOW A CONTINUOUS STREAM OF MOISTURE ACROSS THE AREA WITH VALUES AROUND 0.60-0.80 FROM 12Z THROUGH 18Z AND AFTER BEFORE TRAILING OFF AFTER 00Z SAT. THUS PLENTY OF MOISTURE APPEARS AVAILABLE. FRONTOGENESIS FORCING APPEARS VERY FAVORABLE FOR THIS EVENT...AGAIN SHOWING A PERIOD STRONG FORCING MID DAY FRIDAY. THUS WITH HIGH MOISTURE AND VERY GOOD FORCING EXPECT BANDS OF SNOW ACROSS THE AREA ON FRIDAY. AGAIN...HEAVIEST AMOUNTS WILL BE ACROSS THE SOUTHERN PARTS OF FORECAST AREA...WITH LIGHTER AMOUNTS NORTHWEST. WITH ONGOING PRECIP EXPECTED ON FRIDAY HAVE TRENDED TEMPS COOLER THAN MAV...STEADY IN THE UPPER 20S. ON FRIDAY NIGHT...DEEP MOISTURE IS LOST IN THE FORECAST SOUNDINGS AS BEST FORCING IS LOST AND THE SOUTHERN STREAM SHIFTS EAST. HIGH PRESSURE OVER THE CENTRAL PLAINS CONTINUES TO BUILD ACROSS THE REGION A COLD SURFACE RIDGE BUILDS ACROSS CENTRAL ILLINOIS AND CENTRAL INDIANA. THUS WILL TREND TOWARD A BECOMING PARTLY CLOUDY SKY. A FEW LINGERING SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE ACROSS THE EAST AS FRIDAY/S SYSTEM DEPARTS. HIGH PRESSURE WILL PROVIDE COLD BUT DRY WEATHER FOR SATURDAY. FORECAST SOUNDINGS REMAIN QUITE DRY. THUS WILL TREND TOWARD A PARTLY CLOUDY SKY. AS FOR TEMPS DURING THIS PERIOD...GIVEN THE EXPECTED FRESH SNOW AND COLD AIR IN PLACE WILL TREND HIGHS AND LOWS COOLER THAN MAVMOS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... ISSUED AT 252 PM EST THU DEC 5 2013 MAIN ISSUE IN THE LONG TERM IS ANOTHER WINTER SYSTEM POSSIBLY IMPACTING THE AREA EARLY SUNDAY INTO SUNDAY NIGHT. MODELS APPEAR THEY MAY BE TRENDING SLIGHTLY COOLER MAINLY DURING THE DAY ON SUNDAY. PRECIP MAY SNEAK INTO THE SOUTHERN FORECAST AREA AROUND DAYBREAK SUNDAY IN THE FORM OF SNOW...WITH LIGHT SNOW POTENTIALLY ACROSS MUCH OF THE AREA SUNDAY MORNING. PRECIP MAY TRANSITION TO A MIX OF SLEET AND SNOW WITH SOME FREEZING RAIN POSSIBLE ACROSS THE SOUTHWEST SUNDAY AFTERNOON. THIS MIX POTENTIAL WILL EXPAND A BIT FURTHER NORTHWEST SUNDAY EVENING BEFORE COLD AIR AGAIN OVERTAKES THE AREA AND MOST PRECIP LATE SUNDAY NIGHT CHANGES BACK TO SNOW...WITH THE EXCEPTION OF A LIGHT MIX POSSIBLE IN THE EAST. AMOUNTS WITH THIS SYSTEM...WHILE STILL QUITE UNCERTAIN BEING SO FAR OUT...APPEAR VERY LIGHT ACROSS MOST OF THE FORECAST AREA. ACROSS THE SOUTHEASTERN HALF OF THE AREA...FROM VINCENNES TO INDIANAPOLIS AND MUNCIE SOUTHEASTWARD...1-3 INCHES OF SNOW/SLEET APPEAR POSSIBLE WITH POTENTIAL FOR A FEW HUNDREDTHS OF FREEZING RAIN. SNOW/SLEET ACCUMULATIONS OF UP TO 4 INCHES APPEAR POSSIBLE ACROSS THE FAR SOUTHEASTERN FORECAST AREA...IN THE NORTH VERNON AREA. ONCE THIS SYSTEM EXITS...DRY WEATHER WILL DOMINATE THE REMAINDER OF THE FORECAST PERIOD...AND TEMPS WILL TURN SHARPLY COLDER. HIGHS MAY NOT GET OUT OF THE TEENS AT TIMES NEXT WEEK. ALLBLEND HANDLED THE OUTER PERIODS WELL AND FEW CHANGES WERE REQUIRED. && .AVIATION /DISCUSSION FOR 060600Z TAF ISSUANCE/... ISSUED AT 1135 PM EST THU DEC 5 2013 IFR AND LOWER CONDITIONS EXPECTED AT ALL BUT KLAF WITH LIGHT TO MODERATE SNOW FALLING THROUGH THE OVERNIGHT AND THROUGH THE DAY FRIDAY. VISIBILITIES IN THE SNOW ARE GENERALLY RUNNING 1 TO 2 MILES WITH SHORT BOUTS OF 1/4 TO 3/4SM WHEN A HEAVIER BAND DEVELOPS. LOOKING AT UPSTREAM OBSERVATIONS AND FORECAST SOUNDINGS LOOKS LIKE THE BEST SHOT FOR THIS TO HAPPEN AGAIN AT THE SITES WILL BE IN THE 6 TO 9Z TIMEFRAME AT KHUF AND KIND AND A BIT LATER AT KBMG SO WILL CONTINUE TO TEMPO IN THE LOWER CONDITIONS THEN. LIGHT TO MODERATE SNOWFALL WILL CONTINUE THROUGH THE DAY FRIDAY WITH IFR CONDITIONS EXPECTED. SNOW COULD OCCUR FOR A FEW HOURS AT KLAF FROM LATE MORNING TO MID AFTERNOON BUT EXPECT MVFR THERE. CONDITIONS SHOULD START TO IMPROVE BY 0Z SATURDAY AS THE WINTER SYSTEM MOVES OUT OF THE AREA. && .IND WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL MIDNIGHT EST FRIDAY NIGHT FOR INZ037- 039>042-044>049-051>057-060>065-067>072. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST FRIDAY NIGHT FOR INZ021-028>031-035-036-038-043. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA/MK SHORT TERM...PUMA LONG TERM....NIELD AVIATION...CP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1128 AM CST FRI DEC 6 2013 .SHORT TERM /TODAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY. RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE MORNING. NO CHANGES TO EXISTING HEADLINE. .LONG TERM /TONIGHT THROUGH THURSDAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD. ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING. THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5 ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL CONTINUE TO MONITOR TRENDS. THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND. HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT TEMPS. && .AVIATION...06/18Z ISSUED AT 1125 AM CST FRI DEC 6 2013 VFR CONDITIONS EXPECTED AT SITES THROUGH PERIOD. WINDS WILL REMAIN TO THE NORTHWEST AND BECOME LIGHTER AFTER 00Z. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...SMALL LONG TERM...FAB AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
541 AM CST FRI DEC 6 2013 .SHORT TERM /TODAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY. RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE MORNING. NO CHANGES TO EXISTING HEADLINE. .LONG TERM /TONIGHT THROUGH THURSDAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD. ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING. THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5 ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL CONTINUE TO MONITOR TRENDS. THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND. HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT TEMPS. && .AVIATION...06/12Z ISSUED AT 541 AM CST FRI DEC 6 2013 VFR CONDITIONS ANTICIPATED THROUGH THE PERIOD. MOSTLY CLEAR NORTH WITH MID CLOUD CIGS THROUGHOUT THE DAY SOUTHEAST. NW WINDS WILL REMAIN STEADY AND CHANGE LITTLE. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR CALHOUN-CERRO GORDO- EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC- WINNEBAGO-WORTH. && $$ SHORT TERM...SMALL LONG TERM...FAB AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
407 AM CST FRI DEC 6 2013 .SHORT TERM /TODAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY. RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE MORNING. NO CHANGES TO EXISTING HEADLINE. .LONG TERM /TONIGHT THROUGH THURSDAY/... ISSUED AT 347 AM CST FRI DEC 6 2013 TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD. ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING. THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5 ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL CONTINUE TO MONITOR TRENDS. THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND. HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT TEMPS. && .AVIATION...06/06Z ISSUED AT 1129 PM CST THU DEC 5 2013 VFR CONDITIONS WITH BREEZY NORTHWEST WINDS WILL PERSIST THROUGH THE PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR CALHOUN-CERRO GORDO- EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC- WINNEBAGO-WORTH. && $$ SHORT TERM...SMALL LONG TERM...FAB AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
310 AM CST FRI DEC 6 2013 .SYNOPSIS... ISSUED AT 307 AM CST FRI DEC 6 2013 LATEST SURFACE ANALYSIS INDICATED A SURFACE RIDGE OF HIGH PRESSURE BUILDING EAST SOUTHEASTWARD INTO IOWA AND ILLINOIS. A COLD FRONT WAS DRAPED FROM THE SOUTHERN TIP OF TEXAS NORTHEAST TO NEW YORK. MID AND HIGH LEVEL CLOUDINESS FROM THE NORTHWEST PERIPHERY OF THE WINTER STORM SYSTEM TO THE SOUTH AND SOUTHEAST IS SEEN STREAMING NORTHEAST ACROSS THE CWFA. NORTHWEST WINDS AT 8 TO 15 MPH WERE OBSERVED AT 3AM...WITH A FEW GUSTS AROUND 20 MPH. TEMPERATURES RANGE FROM 7 TO 17 DEGREES...WITH THE WARMER READINGS IN THE SOUTHEAST...CLOSER TO THE SOUTHERN WINTER STORM. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 307 AM CST FRI DEC 6 2013 RELATIVELY QUIET AND COLD CONDITIONS WILL CHARACTERIZE THE WEATHER IN THE SHORT TERM. ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE AREA OVER THE NEXT 24 HOURS. SOME MID AND HIGH LEVEL CLOUDINESS WILL CONTINUE TO OVERSPREAD THE AREA FROM THE SOUTHWEST TODAY...WITH CLEARING CONDITIONS TONIGHT. FLURRIES MAY BE POSSIBLE ACROSS THE SOUTHEAST 1/4 OF THE CWFA...BUT OPTED TO LEAVE MENTION OUT OF GRIDS AT THIS TIME. WINDS WILL REMAIN ON THE BLUSTERY SIDE THROUGH THE MAJORITY OF THE PERIOD...DIMINISHING UNDER 10 MPH BY SATURDAY MORNING. TEMPERATURES LOOK TO BE ON TRACK...WITH HIGHS TODAY STRUGGLING TO REACH THE TEENS AND LOWER 20S. LOWERED MINS SAT MORNING JUST A TAD WITH CLEAR SKIES AND LIGHTER WINDS...WITH MINS IN THE MINUS 3 TO 8 ABOVE RANGE. WIND CHILLS THIS MORNING WILL SLIP INTO THE LOWER SINGLE DIGITS ABOVE ZERO EAST NEAR PRINCETON ILLINOIS...TO ABOUT MINUS 15 NEAR INDEPENDENCE. THIS AFTERNOON THEY WILL BE BETWEEN 5 BELOW AND 10 ABOVE. WITH THE COLDER MINS SATURDAY MORNING...WIND CHILLS WILL DROP TO BETWEEN 5 BELOW AND 18 BELOW ZERO. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 307 AM CST FRI DEC 6 2013 BELOW NORMAL TEMPERATURES ARE THE RULE THROUGHOUT THE EXTENDED FORECAST. CHANCES FOR MEASURABLE SNOW CONTINUE FOR SUNDAY AND SUNDAY NIGHT AS UPPER LEVEL IMPULSE IN THE NEARLY MERIDIONAL FLOW CURRENTLY ALONG THE PACIFIC NW COAST ROUNDS THE BASE OF THE UPPER LEVEL TROUGH AND PASSES THROUGH THE FORECAST AREA. SATURDAY INTO SATURDAY NIGHT WILL BE DRY AND COLD AS HIGH PRESSURE OVER THE NORTHERN ROCKIES PLAINS MIGRATES SE THROUGH THE AREA. WITH A SIMILAR AIRMASS IN PLACE AS FRIDAY...HIGHS WILL ONLY MAKE THE TEENS TO NEAR 20 IN THE FAR SOUTH. CLOUDS THICKEN SATURDAY NIGHT AS MID AND UPPER LEVEL MOISTURE AND MODEST LIFT INCREASES AHEAD OF THE APPROACHING SHORTWAVE. A DEVELOPING E-SE FLOW OF DRY AIR FROM THE SURFACE THROUGH 850 MB SHOULD EFFECTIVELY EAT AWAY AT ANY ICE CRYSTALS...HOLDING OFF THE ONSET OF FLURRIES UNTIL DAYLIGHT SUNDAY. THE CLOUD COVER SHOULD KEEP MINIMUM TEMPERATURES WARMER THAN PREVIOUS NIGHTS...FROM AROUND 10 NORTH TO THE LOWER TEENS ELSEWHERE. SUNDAY AND SUNDAY NIGHT...LIGHT SNOW WILL OVERSPREAD THE AREA FROM WEST TO EAST AS THE UPPER LEVEL VORT MAX AND INVERTED SURFACE TROUGH MOVE THROUGH THE REGION. WHILE THERE ARE STILL MINOR DIFFERENCES BETWEEN MODELS...THE OVERALL TREND IS TOWARD THE BEST UPPER LEVEL FORCING PASSING OVERHEAD FROM MIDDAY INTO EARLY EVENING. MODEL QPF AMOUNTS OF ROUGHLY .05 TO NEARLY .20...ALONG WITH A BRIEF WINDOW OF LIFT IN THE IDEAL DENDRITIC GROWTH ZONE AND SURFACE TEMPERATURES ONLY REACHING THE 20S...WOULD SUPPORT WIDESPREAD SNOWFALL AMOUNTS OF AROUND 1 TO 3 INCHES. THE HIGHER TOTALS WILL LIKELY BE ACROSS THE NW AND NORTH WITH LIGHTEST AMOUNTS IN THE SOUTHEAST. THE VORT MAX PASSES TO THE NORTHEAST AFTER MIDNIGHT...ENDING THE LIGHT SNOW. ALLOWING FOR SOME POSSIBLE FURTHER SLOWING OF THE SYSTEM...HAVE KEPT CHANCE POPS GOING IN THE WEST...WHILE LIKELY POPS HANG ON IN THE FAR NORTHEAST THROUGH THE NIGHT. MONDAY THROUGH THURSDAY...THE FORECAST IS KEPT COLD AND DRY. THERE WILL HOWEVER BE PERIODIC WEAK CLIPPER SYSTEMS IN THE MAINLY NW FLOW ALOFT TO PROVIDE AT LEAST LOW CHANCES FOR FLURRIES OR LIGHT SNOW IN THE VICINITY. AT THIS TIME...MODELS HAVE THE FIRST ONE PASSING TO THE NORTHEAST ON TUESDAY...WITH ANOTHER AROUND WED OR WED NIGHT POSSIBLY TAKING A MORE DIRECT PATH...BUT WITH SIGNIFICANTLY DIFFERENT TIMING BETWEEN THE GFS AND ECMWF NO MENTION OF PRECIPITATION IS INCLUDED IN THE FORECAST AT THIS TIME. THE BIGGER STORY WILL BE THE CONTINUED COLD TEMPERATURES AS 850 MB TEMPERATURES REMAIN IN THE SUB ZERO TEENS. FORECAST HIGHS IN THE TEENS TO MID 20S AND LOWS IN THE SINGLE DIGITS MON THROUGH WED MAY BE TOO OPTIMISTIC...ESPECIALLY IF THE SUNDAY SYSTEM LAYS NEW SNOW COVER ACROSS THE AREA. THURSDAY AND BEYOND...THERE IS INDICATION OF A WARMING TREND AS A SYSTEM DEVELOPS OUT WEST AND THIS IS REFLECTED WITH HIGHS IN THE 20S TO POSSIBLY LOWER 30S IN THE SOUTH THURSDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1150 PM CST THU DEC 5 2013 PATCHY LOW CLOUDS WITH AN OCCASIONAL MVFR CIG ARE CURRENTLY BEING FOUND OVER NORTHEAST IOWA. LATEST RAP MODEL OUTLIER WITH INCREASING THE LOW CLOUDS AND ADVECTING SOUTHEAST OVER MUCH OF AREA ESPECIALLY NORTH OF I-80 OVERNIGHT AND FRIDAY MORNING. WHILE SOME PRESENCE OF LOW LEVEL THETA-E AXIS AND LOW LEVEL FRONTOGENESIS COULD FOSTER ADDITIONAL LOW CLOUDS NOT VERY CONFIDENT TO MENTION ANY CIGS... BUT DID MAINTAIN SCATTERED CLOUD BASES AROUND 2KFT AGL ONLY AT KDBQ FOR NOW BEING CLOSER TO THE ABOVE MENTIONED FEATURES. OTHERWISE...VFR CONDITIONS WITH MID/HIGH CLOUDINESS FROM STORM SYSTEM PASSING TO OUR SOUTH ON FRIDAY. WINDS WILL REMAIN GENERALLY NORTHWEST AROUND 10-15 KTS WITH SOME LOCALLY HIGHER GUSTS POSSIBLE AT TIMES. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...14 SHORT TERM...14 LONG TERM...SHEETS AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1150 PM CST THU DEC 5 2013 .SYNOPSIS... ISSUED AT 318 PM CST THU DEC 5 2013 THE LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE AXIS DRAPED FROM MT...DOWN INTO THE SOUTHEASTERN PLAINS AND LOWER MS RVR VALLEY. THIS TO THE WEST OF LINGERING CYCLONIC PRESSURE GRADIENT ACRS THE UPPER MS RVR VALLEY AND WESTERN GRT LKS AS OCCLUDED SFC LOW COMPLEX SPIRALS JUST WEST OF JAMES BAY. VIS SATELLITE LOOP INDICATING ESTABLISHED SNOW FIELDS ACRS MT...THE DAKOTAS...NORTHERN NEB...MN AND NW WI. COLD LLVL NORTHWEST FETCH OFF THESE SNOW AREAS AND DOWN ACRS IA. ALOFT...12Z UPPER AIR ANALYSIS AND MID/UPPER LEVEL MOISTURE FLOW PATTERNS ON WATER VAPOR IMAGERY LOOP WAS SHOWING DEEP L/W TROF ACRS MUCH OF THE WESTERN CONUS PIVOTING ACRS THE NORTHERN BAJA...WHILE NEARLY STACKED UPPER LOW WAS ROLLING NORTHEASTWARD JUST WEST OF JAMES BAY. THE W/V LOOP ALSO SHOWING LARGE SCALE/LONG FETCH MOISTURE FEED FROM WELL WEST OF THE BAJA CA....UP ACRS MUCH OF THE SOUTHEASTERN HALF OF THE CONUS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 318 PM CST THU DEC 5 2013 TONIGHT...ALTHOUGH THE NORTHWESTERLY SFC WINDS WILL DECREASE TO AROUND 10 TO 12 MPH OVERNIGHT...COLD AIR ADVECTION MACHINE STILL IN FULL GEAR FROM NORTHERN PLAINS SOURCE REGION. STILL EXPECT ROUNDS OF VARYING THICKNESS CIRRUS AND POSSIBLY SOME HIGHER BASED AC OFF OVERRUNNING WINTER STORM SYSTEM ONGOING ACRS THE SOUTHERN PLAINS AND UP THE OH RVR VALLEY. THUS MOSTLY CLOUDY TONIGHT...LITTLE OR NO SNOW COVER...AND MIXING WINDS OF 10+ MPH WILL KEEP TEMPS FROM BOTTOMING OUT TO SUBZERO READINGS. BUT STILL A COLD NIGHT IN STORE WITH LOWS IN THE LOWER SINGLE DIGITS ABOVE ZERO IN THE FAR WEST AND NORTHWEST...5-10 ABOVE TO THE MS RVR...AND LOWER TO MID TEENS EAST OF THE MS RVR. THESE TEMPS COMBINED WITH THE WINDS TO PRODUCE WIND CHILLS FROM ZERO..TO 10-12 BELOW ZERO WEST OF THE MS RVR LATE TONIGHT AND THROUGH 6 AM CST FRI AM. WILL KEEP THE FCST DRY FOR NOW...BUT EXTRAPOLATING SOME OF THE ELEVATED SNOW BANDS IN SOUTH CENTRAL KS NORTHEASTWARD...SOME CHC THAT THEY MAY CLIP THE FAR SOUTHERN CWA OVERNIGHT. BUT IF THEY DO...WILL BANK ON DRIER LLVLS TO LIMIT THEM TO FLURRIES. FRIDAY...ANOTHER COLD DAY CHARACTERIZED BY FILTERED SUNSHINE BY OVERRUNNING CLOUDS OFF STORM SYSTEM JUST OFF TO THE SOUTHEAST. MOSTLY CLOUDY CONDITIONS AND NORTHWEST WINDS OF 10-20 MPH IN LINGERING RIDGE PRESSURE GRADIENT AS IT TRIES TO MAKE HEADWAY AND SLIDE THIS WAY. AGAIN...WILL KEEP THE FCST DRY BUT WOULD NOT BE SURPRISED IF SOME OVERRUNNING FLURRIES OR EVEN LIGHT SNOW OCCASIONALLY CLIP THE FAR SOUTHERN AND SOUTHEASTERN CWA FROM TIME TO TIME. CLOUD COVER AND CONTINUED CAA TO LIMIT HIGH TEMP RECOVERY TO THE MID TEENS IN THE NORTHWEST...TO THE UPPER TEENS OR AROUND 20 DEGREES ALONG AND EAST OF THE MS RVR. ..12.. .LONG TERM...(FRIDAY NIGHT THROUGH NEXT THURSDAY) ISSUED AT 318 PM CST THU DEC 5 2013 THE COLD WEATHER LOOKS LIKE IT WILL BE LOCKED IN OVER THE REGION THROUGH MUCH OF NEXT WEEK WITH THE MODELS KEEPING A PERSISTENT BROAD H5 TROF OVER THE CENTRAL AND WESTERN U.S. DRY AND COLD CONDITIONS ARE EXPECTED SATURDAY AS HIGH PRESSURE MOVES EAST ACROSS NORTHERN IA AND SOUTHERN MN. LOW TEMPERATURES IN THE SINGLE DIGITS LOOK REASONABLE WITH LIGHT WINDS IN THE WEAK GRADIENT NEAR THE HIGH AND CLEAR SKIES. LITTLE MIXING DURING THE DAY SUPPORT TEENS AND LOW 20S FOR HIGHS. A S/W MOVING OUT OF SOUTHWESTERN U.S. TROF AXIS WILL SPREAD MID CLOUDS OVER THE AREA SUNDAY NIGHT. A FLURRY CAN/T BE RULED OUT WEST OF THE RIVER AFTER MIDNIGHT WITH A BROAD REGION OF ISENTROPIC LIFT AND MOISTENING MID LEVELS AHEAD OF THE S/W. HOWEVER...LOW LEVELS REMAIN DRY WHICH SHOULD PREVENT ANY MEASURABLE SNOW. THE INCREASING CLOUD COVER SATURDAY NIGHT WILL KEEP TEMPERATURES FROM FALLING MUCH WITH LOWS AROUND 10 EXPECTED. ACCUMULATING SNOW IS EXPECTED SUNDAY AND SUNDAY NIGHT AS THE S/W MOVES THROUGH THE REGION. THE GFS/ECM HAVE BEEN VERY CONSISTENT PAINTING A BROAD AREA OF QPF OVER THE REGION WITH THIS S/W WITH WATER EQUIVALENTS UP TO TWO TENTHS OF AN INCH. THE ECMWF HAS ALSO BEEN CONSISTENT IN KEEPING THE HIGHER AMOUNTS OVER THE NORTHERN CWFA WHICH LOOKS REASONABLE BASED ON THE THE TRACK OF THE VORT THROUGH NORTHERN MO/ SOUTHERN IA. TEMPERATURES WILL BE COLD ENOUGH FOR SOME HIGH SNOW TO LIQUID RATIOS...POSSIBLY UP TO 20 TO 1 OVER THE NORTHERN CWFA. FOR NOW A CONSERVATIVE 17 TO 1 RATIO WAS USED WHICH PRODUCED 24 HOUR SNOWFALL AMOUNTS OF 2 TO NEARLY 4 INCHES OVER THE NORTHWEST HALF OF THE AREA BETWEEN 12Z SUNDAY AND 12Z MONDAY. FORECAST SNOW AMOUNTS OVER THE SOUTHEAST HALF WERE IN THE 1 TO 2 INCH RANGE. WIND DURING THE EVENT SHOULD STAY AROUND 10KTS OR LESS SO NO SIGNIFICANT BLOWING OR DRIFTING IS EXPECTED. THE SNOW SHOULD BE EAST OF THE AREA BY MONDAY MORNING. ANOTHER SHOT OF VERY COLD AIR IS PULLED SOUTH INTO THE REGION BEHIND SUNDAYS SYSTEM. H8 TEMPS ARE PROGGED TO DIP TO -15 TO -20C BY TUESDAY NIGHT. HIGHS NEXT WEEK SHOULD BE IN THE TEENS AND 20S WITH LOWS MAINLY IN THE SINGLE DIGITS AND TEENS. THE ECM CONTINUES TO SHOW A STRONG HIGH PRESSURE SYSTEM OVER THE REGION BY MID WEEK WITH THIS MORNINGS 12Z RUN INCREASING THE PRESSURE TO 1045MB. IF THIS VERIFIES AND THERE IS SNOW COVER THEN WE COULD SEE LOW TEMPERATURES SIGNIFICANTLY COLDER THAN CURRENTLY FORECAST FOR THE MIDDLE OF THE WEEK. THE GFS ON THE OTHER HAND CONTINUES TO SUGGEST ONE OR TWO WEEK CLIPPER SYSTEM MOVING THROUGH WHICH WOULD ARGUE AGAINST EXTREMELY COLD TEMPERATURES. DLF && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1138 PM CST THU DEC 5 2013 PATCHY LOW CLOUDS WITH AN OCCASIONAL MVFR CIG ARE CURRENTLY BEING FOUND OVER NORTHEAST IOWA. LATEST RAP MODEL OUTLIER WITH INCREASING THE LOW CLOUDS AND ADVECTING SOUTHEAST OVER MUCH OF AREA ESPECIALLY NORTH OF I-80 OVERNIGHT AND FRIDAY MORNING. WHILE SOME PRESENCE OF LOW LEVEL THETA-E AXIS AND LOW LEVEL FRONTOGENESIS COULD FOSTER ADDITIONAL LOW CLOUDS NOT VERY CONFIDENT TO MENTION ANY CIGS... BUT DID MAINTAIN SCATTERED CLOUD BASES AROUND 2KFT AGL ONLY AT KDBQ FOR NOW BEING CLOSER TO THE ABOVE MENTIONED FEATURES. OTHERWISE...VFR CONDITIONS WITH MID/HIGH CLOUDINESS FROM STORM SYSTEM PASSING TO OUR SOUTH ON FRIDAY. WINDS WILL REMAIN GENERALLY NORTHWEST AROUND 10-15 KTS WITH SOME LOCALLY HIGHER GUSTS POSSIBLE AT TIMES. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...12 SHORT TERM...12 LONG TERM...DLF AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1207 AM CST Fri Dec 6 2013 ...UPDATED AVIATION... .SYNOPSIS... ISSUED AT 1115 AM CST THU DEC 5 2013 At 12z Thursday a 1400-160kt 300mb jet extended from northeast Colorado into the western Great Lakes. Another upper level jet was located near the based of the 500mb trough that was positioned from southern California into southwest Montana. A -25 to -32c 500mb thermal trough was located near the four corners region. A surface to 850mb ridge axis was located across from western Nebraska into western Oklahoma and a surface cold front extended from eastern Colorado south southeast across eastern New Mexico into west central Texas. && .SHORT TERM...(This evening through Friday) ISSUED AT 217 PM CST THU DEC 5 2013 Upper level through that was located across southern California and Nevada earlier today will track east and cross New Mexico by late day. Ahead of this this upper trough some mid level moisture will linger across western Kansas. Backing 700mb winds ahead of this upper wave appears to enhance frontogenesis across portions of southwest Kansas late today and early this evening which may give rise to a period of steady light to moderate snow. Both the NAM, GFS, and even the RAP hints at enhanced precipitation briefly ahead of this wave along this baroclinic zone so will follow this trend through midnight as the upper level trough moves out into the central high plains. Given the potential for a period of steadier snow early tonight could easily see snowfall accumulations in the one to two inch range given the high liquid to snow ratio. The area more favorable for this measurable snowfall still appears to be along and south of a Ulysses to Dodge City to Pratt line. Snow totals of around two inches still not out of the question near the Oklahoma border so will trim several counties out of the current winter weather advisory. Tonight the dewpoint will be at or several degrees below zero under mostly cloudy skies. Temperatures will be slow to fall this evening but at this time given these expected low dewpoints, last nights temperatures across northwest Kansas, and the low levels cooling by a couple more degrees have decided to stay close to the guidance for overnight lows. Given these overnight lows ranging from around 1 degree in west central Kansas to near 10 degrees in south central Kansas along with wind speeds of around 10 mph the wind chills by early Friday morning are expected to fall back into the -8 to -15 degree range. The coldest wind chills early Friday morning will be across west central Kansas so will be issuing a wind chill advisory for this area late tonight/early Friday. On Friday the upper level trough will move east into the mid Mississippi valley. Subsidence behind this disturbance may give rise to some breaks of sun late in the day as high pressure at the surface will continue to build into western Kansas. Despite to break of sunshine the 900-850mb temperatures continue to support highs only in the teens Friday afternoon. .LONG TERM...(Friday night through Thursday) ISSUED AT 209 PM CST THU DEC 5 2013 Friday night: Sfc high pressure will shift off to the east Friday night. This will result in northeasterly winds eventually shifting southeast on the backside of said departing high. A cold night is expected with minimums near 0F. Would not rule out a few negative values if skies clear more than expected. Will have to watch for the potential for a wind chill advisory during the overnight and morning hours. Saturday and beyond: The forecast becomes a bit more interesting during the weekend. An amplified trof will eject from the central Rockies and out across the plains by Sunday. This wave does have some upper level dynamics associated with it (140-150 kt jet streak traverses across the forecast area of responsibility). At the low levels, fairly intense warm air advection, 280-290 Kelvin isentropic lift, and 850-600 mb increasing frontogenesis will lead to snow late Saturday and into Sunday. The more enhanced area of said parameters is forecast along and north of the 850 mb pressure perturbation ...basically the northern half of the forecast area. Models still show low end snow advisory amounts along and north of highway 96. Even some of the GEFS members show 2-4" of snow. There is huge bust potential in temperatures for Sunday, should this snow/snow pack/cloud cover come into fruition. The ECE shows a high of 8 for KDDC versus 22 from the MEX. Will apply a slight bias towards the ECMWF solution versus the GFS. Boise verification shows this guidance doing better than the MEX with the current cold air mass over Kansas. After Sunday, the forecast will remain precipitation free as isentropic downglide and subsidence develops in the wake of the departing synoptic trof. There is some question of when this cold air will be dislodged and more of a low level 850 mb downslope plume will develop. The ECMWF indicates this possibility of seeing "warmer" temperatures (i.e. above freezing) by mid to late next week. The deterministic runs have been fairly consistent over the last few days. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1206 AM CST FRI DEC 6 2013 We will need to watch closely for any IFR ceiling development into the early morning as the back edge of the mid level cloud shield exits the region. Enough mid level cloud should remain however to keep low stratus development to a minimum, but the HRRR does hint at the possibility of localized IFR/LIFR stratus development which is too low of a chance to include in prevailing or tempo groups. && .PRELIMINARY POINT TEMPS/POPS... DDC 15 0 16 8 / 0 0 30 40 GCK 15 0 13 7 / 0 0 30 50 EHA 13 1 17 9 / 0 0 30 40 LBL 15 0 15 8 / 0 0 30 40 HYS 15 0 15 6 / 0 0 40 60 P28 21 4 20 10 / 10 0 40 40 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY until 9 AM CST /8 AM MST/ this morning FOR KSZ043-044-061>063. && $$ SYNOPSIS...Burgert SHORT TERM...Burgert LONG TERM...Sugden AVIATION...Russell
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1019 AM EST Fri Dec 6 2013 ...Forecast Update... Issued at 1010 AM EST Fri Dec 6 2013 Made some minor tweaks to the grids this morning to better define sleet/freezing rain/plain rain areas. This didn`t result in any major changes so our winter weather headlines will stay in the same areas for now. However, the changes did give Butler/Nelson counties a bit more freezing rain based on an ice glaze from freezing rain already reported in Butler County this morning and current sfc temp gradient orientation. Overall, dual pol CC`s show the melting layer over southern Indiana through Dubois, Orange, and Washington counties. Just got reports of a change over from sleet to snow in NW Dubois County which confirms that freezing level shown by dual pol data. For the rest of the morning expect mainly sleet/freezing rain over southern Indiana with a slow change over to all snow occurring from the NW to SE. North central KY should largely be light freezing rain with some areas near the Ohio River seeing some sleet by late morning. The rain/freezing rain line as of 15Z was from roughly Morgantown, KY to Frankfort, KY. Expect that line to slowing move ESE through the day as well. Lexington/Bowling Green areas are still looking to see a change over to freezing rain in the 2-4 pm time frame. Of note, with such warm ground temps ahead of this weather system earlier this week, areas running in the 30-32 degree range are seeing ice accums mainly on elevated sfcs. Road impacts are more common where sfc temps are less than 30 degrees. Issued at 635 AM EST Fri Dec 6 2013 Secondary surge of moisture is building across Missouri and Arkansas this hour, and latest SPC mesoanalysis has another frontogenetical band in the area where banding currently is setting up from KBMG to KCGI. Latest HRRR is close to current thinking for snow numbers across our region, 6-10" over our far northwest counties and 3-6" along the river. The southern end of the warning still has freezing rain to deal with. We have had a few glazing reports across the current freezing rain area, which still includes KSDF, though the intensity has slackened. No headline changes coming still, just expect conditions to worsen later this morning into the afternoon. Issued at 455 AM EST Fri Dec 6 2013 Active convection well to out south, and closer to the cold front, appears to be stealing some of our thunder as far the winter precip goes. Have a very apparent dry slot forming between this convection, the northern edge of which now is over Lake Cumberland, and the heavier sleet across southern Indiana. Even the latter band is starting to wane as moisture is getting cut off from it. The GEM and SREF both did a better job of handling this break in the precip, but both fill that gap back in later this morning and into the afternoon. Have adjusted totals and early pops to account for these differences. The overall daytime forecast did not change much, so will not issue a zone update and no changes to the headline products are expected at this time. .SHORT TERM (Now through Saturday Night)... Issued at 330 AM EST Fri Dec 6 2013 ...IMPACTFUL WINTER EVENT ONGOING... Southwest feed of moisture is pumping in plenty of moisture and working with Arctic air filtering into the region to create a messy winter precip forecast this morning. Freezing rain line running roughly from Russellville in Logan county to Etown/Louisville to Frankfort. Had a band of heavier returns across our northern row of counties, where sleet is coming down. SPC mesoanalysis earlier showed a band of 850-700 mb frontogenesis where this band formed, but that band has spread out now. Timing for cold air continues to run a bit faster than previously forecast, so have had to shift freezing rain timing south. Given timing for precip coming in, that would also mean higher snow totals over the north, where the deeper cold air will allow for a quicker transition to snow during the day today. Bumped up the totals across our northern counties to 6-10 inches, with areas right along the Ohio River now getting between 2 and 6 inches. Current headlines still look good. The northern part of the winter storm warning looks solid for reaching the heavy snow criteria, whereas the southern part looks like the combination of freezing rain, sleet, and snow will be the main threat. The advisory area looks in line for around an inch of snow and/or a tenth to a quarter inch of freezing rain. Moisture tap runs out aloft starts to run out this evening. Soundings show we may have a period of freezing drizzle, as the top of the saturated layer gets warmer than -10C. Given temperatures falling quickly, this freezing drizzle combined with already wet roadways and temperatures well into the 20s will make for continued dangerous travel conditions overnight. Highs Saturday will struggle to get into the lower 20s, if that high, over southern Indiana in the snowpack. Down south, the freezing mark will be the hard point to reach. The cold temperatures will set the stage for the next system to come in, read on below. .LONG TERM (Sunday through Friday)... Issued at 320 AM EST Fri Dec 6 2013 ...SIGNIFICANT WINTRY WEATHER EXPECTED LATE SATURDAY NIGHT AND SUNDAY ACROSS THE REGION... ...Saturday night through Monday... Ding, ding! Round two of wintry weather will commence late Saturday night and through the day Sunday, as our next mid-level southern stream wave heads northeastward. Precip may begin across southern Kentucky around midnight, but models seem to rush it in after midnight. Precipitation types are still a difficult forecast, which depends on the final snow/sleet/ice totals from this first round of wintry precip today. Currently believe surface temperatures will be cold and the depth of the cold airmass will be sufficiently deep to support mostly snow at the precipitation onset. The snow could be particularly heavy early Sunday across portions of southern Indiana and central Kentucky. As the wave continues to move northeast, warmer air aloft would eventually overspread the cold lower layer and result in a change over to perhaps sleet for a very brief period, but freezing rain would quickly take over and progress northward. Still too difficult to pin down the snow and freezing rain amounts, but they could accumulate rapidly before warmer surface air arrives. Speaking of that, warmer air will work in at the surface across southern Kentucky in the afternoon, changing freezing rain over to rain. This too will continue northward into the evening as the wave shifts northeast. In fact, the warmest temperatures Sunday may very well occur in the evening as the warmer surface air gets in here. As the wave departs, colder air rushes back in and will lead to any leftover precipitation changing back over to snow before ending. Highs Sunday look to warm to around the freezing mark in areas north of the Ohio River late in the day, with mid to upper 30s across much of Kentucky. Lows Sunday night will cool back into the lower 30s. Highs on Monday are really tough because they will be so dependent on snow/ice cover. Right now will go with highs in the lower 30s across the northwest to lower 40s across the southeast. Monday Night through Thursday... Will keep a slight chance of light snow over far eastern and southeastern counties Monday evening as broad shortwave aloft moves through. Otherwise, weather during this period calms down as flow aloft becomes less amplified with no noticeable weather systems to track across our area. This period looks dry, even with a shortwave trough diving through the Great Lakes Thursday. Any precip associated with that trough appears to stay north of the area. Temperatures will be the big story. It will be quite cold with highs in the 20s across the north and 30s across the south Tuesday through Thursday, with lows generally in the single digits across the north and teens across the southern CWA. As mentioned in the previous forecast, whatever snow cover exists in our north will affect these numbers. && .HYDROLOGY... Issued at 315 PM EDT Thu Dec 5 2013 A prolonged period of precipitation will continue into the weekend. The first system has already dumped up to an inch and another 1 to 2 inches are expected before the precipitation ends Friday night. The northern portions will see much of this precipitation change over to freezing or frozen forms. Thus, rises will occur on rivers and streams but no flooding on major rivers is expected. However, localized flooding could still occur tonight into Friday. The second system Saturday night through Sunday could drop an additional 1 to 2 inches of precipitation is expected over southeast Kentucky. Again, the precipitation will be a mixture of frozen and freezing types and will runoff slower than pure rain. This next shot could trigger some minor flooding on parts of the Green, Licking, and Salt basins. If so, flooding will extend into next week. && .AVIATION (12Z TAF Update)... Updated at 640 AM EST Fri Dec 6 2013 There is a bit of a lull in precipitation occurring across the region as moisture aloft has diminished a bit. This is leading to or will lead to more of a freezing drizzle and very light sleet situation for a few hours this morning rather than the steadier rain. However, our next wave is just southwest of the area and deep moisture will quickly spread across the region once again. Precipitation intensity will increase and as the temperature profile continues to cool, precip type will change through the day. Expect precip to end this evening and overnight in the form of light freezing drizzle/light sleet as we once again lose the upper-level moisture with the system departing. Expect IFR ceilings will be common now and through the evening before starting to transition to MVFR toward the end of the TAF period. Visibilities will also decrease in the heavier precip later today. Winds will continue to be out of the north at 9-14 knots. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR KYZ023>038. WINTER WEATHER ADVISORY until 1 AM EST /Midnight CST/ Saturday FOR KYZ039>043-045>049-053>055-061>063-070>072. IN...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR INZ076>079-083-084-089>092. && $$ Update.........AMS Short Term.....RJS Long Term......MJP Hydrology......CMC Aviation.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
641 AM EST Fri Dec 6 2013 ...Updated Aviation and Forecast Discussion... ...Forecast Update... Issued at 635 AM EST Fri Dec 6 2013 Secondary surge of moisture is building across Missouri and Arkansas this hour, and latest SPC mesoanalysis has another frontogenetical band in the area where banding currently is setting up from KBMG to KCGI. Latest HRRR is close to current thinking for snow numbers across our region, 6-10" over our far northwest counties and 3-6" along the river. The southern end of the warning still has freezing rain to deal with. We have had a few glazing reports across the current freezing rain area, which still includes KSDF, though the intensity has slackened. No headline changes coming still, just expect conditions to worsen later this morning into the afternoon. Issued at 455 AM EST Fri Dec 6 2013 Active convection well to out south, and closer to the cold front, appears to be stealing some of our thunder as far the winter precip goes. Have a very apparent dry slot forming between this convection, the northern edge of which now is over Lake Cumberland, and the heavier sleet across southern Indiana. Even the latter band is starting to wane as moisture is getting cut off from it. The GEM and SREF both did a better job of handling this break in the precip, but both fill that gap back in later this morning and into the afternoon. Have adjusted totals and early pops to account for these differences. The overall daytime forecast did not change much, so will not issue a zone update and no changes to the headline products are expected at this time. .SHORT TERM (Now through Saturday Night)... Issued at 330 AM EST Fri Dec 6 2013 ...IMPACTFUL WINTER EVENT ONGOING... Southwest feed of moisture is pumping in plenty of moisture and working with Arctic air filtering into the region to create a messy winter precip forecast this morning. Freezing rain line running roughly from Russellville in Logan county to Etown/Louisville to Frankfort. Had a band of heavier returns across our northern row of counties, where sleet is coming down. SPC mesoanalysis earlier showed a band of 850-700 mb frontogenesis where this band formed, but that band has spread out now. Timing for cold air continues to run a bit faster than previously forecast, so have had to shift freezing rain timing south. Given timing for precip coming in, that would also mean higher snow totals over the north, where the deeper cold air will allow for a quicker transition to snow during the day today. Bumped up the totals across our northern counties to 6-10 inches, with areas right along the Ohio River now getting between 2 and 6 inches. Current headlines still look good. The northern part of the winter storm warning looks solid for reaching the heavy snow criteria, whereas the southern part looks like the combination of freezing rain, sleet, and snow will be the main threat. The advisory area looks in line for around an inch of snow and/or a tenth to a quarter inch of freezing rain. Moisture tap runs out aloft starts to run out this evening. Soundings show we may have a period of freezing drizzle, as the top of the saturated layer gets warmer than -10C. Given temperatures falling quickly, this freezing drizzle combined with already wet roadways and temperatures well into the 20s will make for continued dangerous travel conditions overnight. Highs Saturday will struggle to get into the lower 20s, if that high, over southern Indiana in the snowpack. Down south, the freezing mark will be the hard point to reach. The cold temperatures will set the stage for the next system to come in, read on below. .LONG TERM (Sunday through Friday)... Issued at 320 AM EST Fri Dec 6 2013 ...SIGNIFICANT WINTRY WEATHER EXPECTED LATE SATURDAY NIGHT AND SUNDAY ACROSS THE REGION... ...Saturday night through Monday... Ding, ding! Round two of wintry weather will commence late Saturday night and through the day Sunday, as our next mid-level southern stream wave heads northeastward. Precip may begin across southern Kentucky around midnight, but models seem to rush it in after midnight. Precipitation types are still a difficult forecast, which depends on the final snow/sleet/ice totals from this first round of wintry precip today. Currently believe surface temperatures will be cold and the depth of the cold airmass will be sufficiently deep to support mostly snow at the precipitation onset. The snow could be particularly heavy early Sunday across portions of southern Indiana and central Kentucky. As the wave continues to move northeast, warmer air aloft would eventually overspread the cold lower layer and result in a change over to perhaps sleet for a very brief period, but freezing rain would quickly take over and progress northward. Still too difficult to pin down the snow and freezing rain amounts, but they could accumulate rapidly before warmer surface air arrives. Speaking of that, warmer air will work in at the surface across southern Kentucky in the afternoon, changing freezing rain over to rain. This too will continue northward into the evening as the wave shifts northeast. In fact, the warmest temperatures Sunday may very well occur in the evening as the warmer surface air gets in here. As the wave departs, colder air rushes back in and will lead to any leftover precipitation changing back over to snow before ending. Highs Sunday look to warm to around the freezing mark in areas north of the Ohio River late in the day, with mid to upper 30s across much of Kentucky. Lows Sunday night will cool back into the lower 30s. Highs on Monday are really tough because they will be so dependent on snow/ice cover. Right now will go with highs in the lower 30s across the northwest to lower 40s across the southeast. Monday Night through Thursday... Will keep a slight chance of light snow over far eastern and southeastern counties Monday evening as broad shortwave aloft moves through. Otherwise, weather during this period calms down as flow aloft becomes less amplified with no noticeable weather systems to track across our area. This period looks dry, even with a shortwave trough diving through the Great Lakes Thursday. Any precip associated with that trough appears to stay north of the area. Temperatures will be the big story. It will be quite cold with highs in the 20s across the north and 30s across the south Tuesday through Thursday, with lows generally in the single digits across the north and teens across the southern CWA. As mentioned in the previous forecast, whatever snow cover exists in our north will affect these numbers. && .HYDROLOGY... Issued at 315 PM EDT Thu Dec 5 2013 A prolonged period of precipitation will continue into the weekend. The first system has already dumped up to an inch and another 1 to 2 inches are expected before the precipitation ends Friday night. The northern portions will see much of this precipitation change over to freezing or frozen forms. Thus, rises will occur on rivers and streams but no flooding on major rivers is expected. However, localized flooding could still occur tonight into Friday. The second system Saturday night through Sunday could drop an additional 1 to 2 inches of precipitation is expected over southeast Kentucky. Again, the precipitation will be a mixture of frozen and freezing types and will runoff slower than pure rain. This next shot could trigger some minor flooding on parts of the Green, Licking, and Salt basins. If so, flooding will extend into next week. && .AVIATION (12Z TAF Update)... Updated at 640 AM EST Fri Dec 6 2013 There is a bit of a lull in precipitation occurring across the region as moisture aloft has diminished a bit. This is leading to or will lead to more of a freezing drizzle and very light sleet situation for a few hours this morning rather than the steadier rain. However, our next wave is just southwest of the area and deep moisture will quickly spread across the region once again. Precipitation intensity will increase and as the temperature profile continues to cool, precip type will change through the day. Expect precip to end this evening and overnight in the form of light freezing drizzle/light sleet as we once again lose the upper-level moisture with the system departing. Expect IFR ceilings will be common now and through the evening before starting to transition to MVFR toward the end of the TAF period. Visibilities will also decrease in the heavier precip later today. Winds will continue to be out of the north at 9-14 knots. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR KYZ023>038. WINTER WEATHER ADVISORY until 1 AM EST /Midnight CST/ Saturday FOR KYZ039>043-045>049-053>055-061>063-070>072. IN...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR INZ076>079-083-084-089>092. && $$ Update.........RJS Short Term.....RJS Long Term......MJP Hydrology......CMC Aviation.......MJP
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1127 PM CST Thu Dec 5 2013 .UPDATE... ISSUED AT 1118 PM CST THU DEC 5 2013 Updated the aviation discussion for the 06Z TAF issuance. UPDATE ISSUED AT 815 PM CST THU DEC 5 2013 Currently making only minor adjustments to snow/sleet locations in the grids. There are some slight differences between the latest NAM and RAP soundings with the NAM a tad warmer. Will keep the mix but move the snow line a bit farther south. Will up snow amounts in some areas as Du Quoin is already measuring 2 inches. Over SEMO now getting reports of sleet. CC product from radar indicating a mix of snow with bursts of sleet. Expect that to continue for a good portion of the night except for the extreme southeast 3 or 4 counties where there might be more icing. There is currently a lull over west Kentucky but we expect this to fill in slowly as precipitation is increasing to our south. The RAP and NAM models keeps a general lull over west Kentucky through about 9z. Models seem to be hinting at the increase in intensity over the entire area around midday tomorrow. && .SHORT TERM...(This Evening through Saturday) ISSUED AT 331 PM CST THU DEC 5 2013 The winter storm is a couple of hours earlier than expected, but the overall evolution has been as expected so far. The precipitation has quickly transitioned to sleet over much of southeast Missouri and southern Illinois. Will allow the warning to continue as is. The main shift in guidance, led by the 12Z NAM is to hang onto a very warm layer aloft longer into the event. The southeast corner of the area may never see much in the way of snow before the precipitation ends. The forecast has been shift a bit more toward freezing rain/ice and less sleet and snow over much of west Kentucky and Missouri Boot Heel region. A half inch of ice is likely over much of this area, with just an inch or two of sleet and snow. Over the northern portions of the area the 6-8" swath of sleet and snow still looks good, and may not be high enough given some sleet accumulations we have already received this afternoon. The overall timing remains the same with the precipitation coming to a rapid end from west to east Friday afternoon. North winds generally 10 to 15 mph will continue to bring in much cooler air through the short term period. Single digit temperatures are expected over much of the area Friday night, and negative wind chills are now forecast over much of the area Friday night as well. .LONG TERM...(Saturday Night through Thursday) ISSUED AT 331 PM CST THU DEC 5 2013 Models continue to show low pressure over the western Gulf of Mexico 12z Sunday, with an inverted trof extending east of the PAH forecast area. Models continue to trend a little farther east, which would lessen amounts across our area. However, this will also keep our region in colder air, thus indicating a more persistent wintry mix and less potential for our southeast counties, where the highest QPF should be, to change to rain on Sunday. Precipitation will spread northwest across our counties late Saturday night and continue through the day Sunday. Light amounts of snow, sleet and a little freezing rain will be possible across southeast Missouri, southern Illinois and southwest Indiana by the time the precipitation ends late Sunday afternoon or Sunday evening. Across west Kentucky, and possibly into extreme southeast Missouri and extreme southern Illinois, more significant amounts of freezing rain and sleet are possible. With almost all of the region below freezing through the entire event, whatever falls will freeze and/or accumulate. Southern portions of the Pennyrile region of west Kentucky have the best chance for temperatures to climb above freezing, but with the best QPF in this area, a tenth to a quarter inch of ice accumulation will be possible before the temperatures potentially climb to above freezing. Lesser amounts of ice are expected across the rest of west Kentucky and adjacent areas. Overall confidence is not very high right now, due to current models trends, but fortunately amounts have trended downward from a couple of days ago. If the GFS pans out, amounts would still be pretty significant, but ECMWF, NAM and GEM all show higher QPF mainly over portions of west Kentucky or to our east. Also, how much snow/ice pack is left from the winter event just getting started across our region will have an impact on temperatures and potential accumulations. By late Sunday night the wintry precip, mainly snow and sleet by that point, should gradually taper off from west to east, with a return of dry conditions after 12z Monday. High pressure will build across the Central Plains Monday and slowly slide east through mid week, centered over the middle Mississippi valley by 12z Wednesday. Very cold air will settle into our region for the early part of the work week. Highs Monday will range from the middle 20s north to the lower 30s south, then only in the 20s area wide Tuesday. Lows both Monday night and Tuesday night will range from the middle single digits north to the middle teens southeast. By Wednesday and Thursday, with plenty of sunshine, high temperatures will rebound a little, back into the middle 20s to middle 30s. && .AVIATION... ISSUED AT 1118 PM CST THU DEC 5 2013 Cigs and/or vsbys at all sites will gradually decrease from MVFR to IFR by mid period, then back to MVFR toward the end of the cycle. Snow/sleet at KCGI should change over to all snow around 15Z. Freezing rain/sleet at KPAH/KEVV/KOWB should change over to snow between 15-18Z. Northerly winds 10-15 mph gusting up to 20 mph should subside somewhat by the end of the period. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...WINTER STORM WARNING until 6 PM CST Friday FOR ILZ075>078- 080>094. MO...WINTER STORM WARNING until 6 PM CST Friday FOR MOZ076-086-087- 100-107>112-114. IN...WINTER STORM WARNING until 6 PM CST Friday FOR INZ081-082- 085>088. KY...WINTER STORM WARNING until 6 PM CST Friday FOR KYZ001>008-010- 011-013>016-018>020. WINTER STORM WARNING until 9 PM CST Friday FOR KYZ009-012-017- 021-022. && $$ SHORT TERM...PS AVIATION...JP
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1206 PM CST FRI DEC 6 2013 .AVIATION...THE LEADING EDGE OF THE SHALLOW COLD WEDGE OF A COLD FRONT IS JUST BEYOND TERMINAL ARA WITH VLIFR CIGS, DRIZZLE AND FOG EXTENDING BACK INTO ARA AND LFT. TO THE WEST, IFR CIGS WITH A FEW SHOWERS AROUND LCH. PRECIP MORE EXTENSIVE TO THE NORTH AROUND AEX WHERE LIFR CIGS COMBINE WITH VIS CURRENTLY LESS THAN 2 MILES IN A MODERATE BAND OF RAIN AND DRIZZLE WILL SHORTLY BE MOVING EAST WITH VIS TO 3 MILES IMPROVING TO 6 MILES WHILE LIFR CIGS PERSIST THIS AFTERNOON. ALL LOCATIONS SHOULD SEE PRECIP ENDING WITH MVFR CIGS AND GUSTY WINDS THIS EVENING WITH THE EXCEPTION OF ARA WHERE IFR CIGS SHOULD CONTINUE. A FEW SHOWERS COULD REAPPEAR SATURDAY MORNING AS ADDITIONAL MOISTURE MOVES IN ALOFT AS A FRONTAL WAVE DEVELOPS NEAR THE TEXAS COAST. SWEENEY && .PREV DISCUSSION... /ISSUED 1116 AM CST FRI DEC 6 2013/ DISCUSSION... CDFNT FAIRLY EVIDENT ON VISIBLE SATELLITE AND RADAR IMAGERY EXTENDING FROM SOUTH CENTRAL LOUISIANA INTO THE WESTERN GULF...WITH AN EXTENSIVE BLANKET OF POST FRONTAL STRATUS NOW COVERING ALL BUT EXTREME SE INLAND ZONES AND THE SE THIRD OR SO OF THE MAOR. DRIZZLE...ALONG WITH PATCHES OF MODERATE RAIN AND A FEW SHOWERS...PREVAIL IN THE COLD POST FRONTAL AIRMASS. COVERAGE HAS INCREASED OVER THE PAST COUPLE OF HOURS OR SO...AND THIS SHOULD CONTINUE HEADING INTO THE EARLY TO MID AFTERNOON...WITH RAIN CHANCES STARTING TO DECLINE HEADING FROM LATE AFTERNOON THROUGH THE EVENING. WITH THE EXCEPTION OF LOCATIONS AHEAD OF THE FRONT WHERE WARMING IS ONGOING...TEMPERATURES ARE EXPECTED TO REMAIN STEADY IF NOT FALL SLOWLY THROUGH THE DAY. THE CONTRAST IS STRIKING...WITH LATEST OBS FROM LAFAYETTE AND PATTERSON REPORTING 49 AND 79 DEGREES RESPECTIVELY. ACCURATELY DEPICTING THIS PHENOMENON IN THE GRIDS IS QUITE CHALLENGING...BUT GENERALLY SPEAKING...LATEST RUC FCSTS APPEAR TO HAVE THE GREATEST GRASP ON OVERALL SHORT TERM TRENDS...AND THUS WAS RELIED ON HEAVILY FOR THE HRLY FCST THE REST OF TODAY. DID INCLUDE SOME PATCHY FOG OVER SOUTH CENTRAL LOUISIANA WHERE KLFT AND KARA HAVE REPORTED 1/2SM OR LESS AT TIMES THIS MORNING. THIS SHOULD IMPROVE HEADING INTO THE AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS AND MAY HAVE TO ADD IT FOR THIS AFTERNOON/EVENING FOR AREAS STILL DOWNSTREAM OF THE FRONT. HAVE NOT LOOKED TOO DEEPLY AT TONIGHT JUST YET...BUT A QUICK GLANCE REVEALS THE TYPICAL CAVEATS WHICH INCLUDE BORDERLINE FREEZING TEMPERATURES AND WHETHER ANY PCPN WILL BE ONGOING TO FREEZE. WILL BE EXAMINING THAT FURTHER FOR THE AFTERNOON PACKAGE. 13 PREV DISCUSSION... /ISSUED 531 AM CST FRI DEC 6 2013/ DISCUSSION... 12Z TAF ISSUANCE. AVIATION... COLD FRONT NOW ACROSS LOWER ACADIANA...PAST ARA BUT NOT YET REACHED PTN. RADAR SHOWS SCT OVERRUNNING SHRA OVER SE TX/C AND SC LA THIS MORNING...MIXED WITH -DZ NOT DETECTED BY RADAR. OTHERWISE...LIFR CEILINGS WILL CONTINUE THIS MORNING FOR ALL SITES...WITH INTERMITTENT IFR VSBY POSSIBLE AS WELL. SHRA EXPECTED TO INCREASE LATER THIS MORNING INTO THE EARLY AFTERNOON HOURS. CEILINGS ONLY EXPECTED TO IMPROVE TO IFR AT BEST LATER THIS MORNING INTO THE AFTERNOON...WITH IMPROVEMENT TO MVFR THIS EVENING. DML PREV DISCUSSION... /ISSUED 355 AM CST FRI DEC 6 2013/ DISCUSSION... SFC ANALYSIS/88D IMAGERY SHOWS THE FRONT RUNNING ROUGHLY FROM KBTR THROUGH KLFT AND KIYA TO THE COASTAL WATERS SOUTH OF CAMERON. LOCAL 88DS SHOW SCATTERED LIGHT SHOWERS DEVELOPING MAINLY ALONG THE FRONT AND PATCHY LIGHT RAIN BEGINNING TO DEVELOP OVER THE NWRN ZONES. FURTHER NORTH...REGIONAL 88DS SHOW A LARGE AREA OF LIGHT RAIN...WITH SOME FREEZING RAIN MIXED IN...SPREADING ACROSS NRN TX INTO THE ARKLATEX. NO SIGNIFICANT CHANGES WERE MADE TO THE INHERITED GRIDS/ZONES THIS MORNING. 00Z MODEL RUNS INDICATE THE PRECIP SHIELD TO OUR NW WILL CONTINUE PUSHING ESEWD THROUGH THE DAY...MOST AFFECTING THE NRN ZONES WHERE HIGHEST POPS ARE CURRENTLY DISPLAYED. MEANWHILE ADDITIONAL OVERRUNNING-TYPE RAINS ARE EXPECTED TO DEVELOP ACROSS THE REMAINDER OF THE FORECAST AREA AS THE FRONT GRADUALLY GETS A SHOVE FROM FROM THE SHORTWAVE MOVING INTO THE TX BIG BEND REGION AND FINALLY DEPARTS THE SERN ZONES LATER THIS MORNING. AS COLD AIR ASSOCIATED WITH BUILDING CANADIAN HIGH PRESSURE WORKS ITS WAY OVER THE AREA THROUGH TODAY TEMPS ARE EXPECTED TO BASICALLY HOLD IN THE LOWER 40S ACROSS THE NWRN ZONES. STILL LOOKING AT THE POSSIBILITY OF WINTRY WEATHER LATE TONIGHT INTO SATURDAY MORNING ACROSS THE NRN TIER OF ZONES AS FORECAST SOUNDINGS CONTINUE TO INDICATE A SHALLOW SUBFREEZING LAYER NEAR THE SFC. STILL NOT SEEING THE NEED TO EXPAND THIS AREA OF FREEZING PRECIP SWD THOUGH AS FORECAST SOUNDINGS CONTINUE TO SHOW TEMPS STAYING ABOVE 32F FOR NOW. A FAIRLY MESSY WEATHER PATTERN LOOKS ON TAP FOR THE WEEKEND AS THE OVERRUNNING PATTERN LINGERS AND GETS AIDED BY SFC LOW DEVELOPMENT OVER THE WRN GULF. THE PRECIP SHOULD GRADUALLY DIMINISH INTO EARLY NEXT WEEK WHEN THE LONGWAVE TROF AXIS PUSHES EWD ACROSS THE CNTL CONUS AND DRY AIR TAKES OVER THROUGH THE COLUMN. THE CANADIAN AIRMASS PROGGED TO SLIP SWD ACROSS THE WRN/CNTL CONUS WILL MAINTAIN COOL TEMPS THROUGH MID-WEEK. RAIN CHANCES RETURN VERY LATE IN THE FORECAST PERIOD AS A STRONG SHORTWAVE CROSSES THE REGION AND WORKS IN CONCERT WITH PROGGED COASTAL TROF DEVELOPMENT. MARINE... EXTENDED THE DENSE FOG ADVISORY FOR VERMILION BAY/NEAR SHORE WATERS EAST OF INTRACOASTAL CITY TO 15Z AS VERY LOW VISIBILITIES WILL REMAIN A THREAT UNTIL THE FRONT PASSES THIS AREA. ALSO ADDED CAUTION HEADLINES TO SABINE/CALCASIEU LAKES FOR THIS AFTERNOON AS NRLY WINDS ARE EXPECTED TO INCREASE TO THE 15-20 KNOT RANGE. OTHERWISE SCA CONDITIONS ARE EXPECTED TO DEVELOP THROUGH THE AFTERNOON AND EVENING ON THE COASTAL WATERS AS STRONG OFFSHORE DEVELOPS IN WAKE OF THE FRONT. 08 && .PRELIMINARY POINT TEMPS/POPS... KLCH 50 36 43 35 49 / 70 30 50 40 50 KBPT 47 36 44 35 46 / 60 30 50 40 50 KAEX 43 32 41 34 43 / 90 30 50 50 60 KLFT 50 36 44 38 54 / 70 30 50 40 60 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST SATURDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM... WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT 20 NM...WATERS FROM CAMERON LA TO HIGH ISLAND TX FROM 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM...WATERS FROM INTRACOASTAL CITY TO CAMERON LA FROM 20 TO 60 NM. SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES: SABINE LAKE. SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES: CALCASIEU LAKE. SMALL CRAFT EXERCISE CAUTION FROM 3 PM CST THIS AFTERNOON THROUGH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES: VERMILION BAY. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1116 AM CST FRI DEC 6 2013 .DISCUSSION... CDFNT FAIRLY EVIDENT ON VISIBLE SATELLITE AND RADAR IMAGERY EXTENDING FROM SOUTH CENTRAL LOUISIANA INTO THE WESTERN GULF...WITH AN EXTENSIVE BLANKET OF POST FRONTAL STRATUS NOW COVERING ALL BUT EXTREME SE INLAND ZONES AND THE SE THIRD OR SO OF THE MAOR. DRIZZLE...ALONG WITH PATCHES OF MODERATE RAIN AND A FEW SHOWERS...PREVAIL IN THE COLD POST FRONTAL AIRMASS. COVERAGE HAS INCREASED OVER THE PAST COUPLE OF HOURS OR SO...AND THIS SHOULD CONTINUE HEADING INTO THE EARLY TO MID AFTERNOON...WITH RAIN CHANCES STARTING TO DECLINE HEADING FROM LATE AFTERNOON THROUGH THE EVENING. WITH THE EXCEPTION OF LOCATIONS AHEAD OF THE FRONT WHERE WARMING IS ONGOING...TEMPERATURES ARE EXPECTED TO REMAIN STEADY IF NOT FALL SLOWLY THROUGH THE DAY. THE CONTRAST IS STRIKING...WITH LATEST OBS FROM LAFAYETTE AND PATTERSON REPORTING 49 AND 79 DEGREES RESPECTIVELY. ACCURATELY DEPICTING THIS PHENOMENON IN THE GRIDS IS QUITE CHALLENGING...BUT GENERALLY SPEAKING...LATEST RUC FCSTS APPEAR TO HAVE THE GREATEST GRASP ON OVERALL SHORT TERM TRENDS...AND THUS WAS RELIED ON HEAVILY FOR THE HRLY FCST THE REST OF TODAY. DID INCLUDE SOME PATCHY FOG OVER SOUTH CENTRAL LOUISIANA WHERE KLFT AND KARA HAVE REPORTED 1/2SM OR LESS AT TIMES THIS MORNING. THIS SHOULD IMPROVE HEADING INTO THE AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS AND MAY HAVE TO ADD IT FOR THIS AFTERNOON/EVENING FOR AREAS STILL DOWNSTREAM OF THE FRONT. HAVE NOT LOOKED TOO DEEPLY AT TONIGHT JUST YET...BUT A QUICK GLANCE REVEALS THE TYPICAL CAVEATS WHICH INCLUDE BORDERLINE FREEZING TEMPERATURES AND WHETHER ANY PCPN WILL BE ONGOING TO FREEZE. WILL BE EXAMINING THAT FURTHER FOR THE AFTERNOON PACKAGE. 13 && .PREV DISCUSSION... /ISSUED 531 AM CST FRI DEC 6 2013/ DISCUSSION... 12Z TAF ISSUANCE. AVIATION... COLD FRONT NOW ACROSS LOWER ACADIANA...PAST ARA BUT NOT YET REACHED PTN. RADAR SHOWS SCT OVERRUNNING SHRA OVER SE TX/C AND SC LA THIS MORNING...MIXED WITH -DZ NOT DETECTED BY RADAR. OTHERWISE...LIFR CEILINGS WILL CONTINUE THIS MORNING FOR ALL SITES...WITH INTERMITTENT IFR VSBY POSSIBLE AS WELL. SHRA EXPECTED TO INCREASE LATER THIS MORNING INTO THE EARLY AFTERNOON HOURS. CEILINGS ONLY EXPECTED TO IMPROVE TO IFR AT BEST LATER THIS MORNING INTO THE AFTERNOON...WITH IMPROVEMENT TO MVFR THIS EVENING. DML PREV DISCUSSION... /ISSUED 355 AM CST FRI DEC 6 2013/ DISCUSSION... SFC ANALYSIS/88D IMAGERY SHOWS THE FRONT RUNNING ROUGHLY FROM KBTR THROUGH KLFT AND KIYA TO THE COASTAL WATERS SOUTH OF CAMERON. LOCAL 88DS SHOW SCATTERED LIGHT SHOWERS DEVELOPING MAINLY ALONG THE FRONT AND PATCHY LIGHT RAIN BEGINNING TO DEVELOP OVER THE NWRN ZONES. FURTHER NORTH...REGIONAL 88DS SHOW A LARGE AREA OF LIGHT RAIN...WITH SOME FREEZING RAIN MIXED IN...SPREADING ACROSS NRN TX INTO THE ARKLATEX. NO SIGNIFICANT CHANGES WERE MADE TO THE INHERITED GRIDS/ZONES THIS MORNING. 00Z MODEL RUNS INDICATE THE PRECIP SHIELD TO OUR NW WILL CONTINUE PUSHING ESEWD THROUGH THE DAY...MOST AFFECTING THE NRN ZONES WHERE HIGHEST POPS ARE CURRENTLY DISPLAYED. MEANWHILE ADDITIONAL OVERRUNNING-TYPE RAINS ARE EXPECTED TO DEVELOP ACROSS THE REMAINDER OF THE FORECAST AREA AS THE FRONT GRADUALLY GETS A SHOVE FROM FROM THE SHORTWAVE MOVING INTO THE TX BIG BEND REGION AND FINALLY DEPARTS THE SERN ZONES LATER THIS MORNING. AS COLD AIR ASSOCIATED WITH BUILDING CANADIAN HIGH PRESSURE WORKS ITS WAY OVER THE AREA THROUGH TODAY TEMPS ARE EXPECTED TO BASICALLY HOLD IN THE LOWER 40S ACROSS THE NWRN ZONES. STILL LOOKING AT THE POSSIBILITY OF WINTRY WEATHER LATE TONIGHT INTO SATURDAY MORNING ACROSS THE NRN TIER OF ZONES AS FORECAST SOUNDINGS CONTINUE TO INDICATE A SHALLOW SUBFREEZING LAYER NEAR THE SFC. STILL NOT SEEING THE NEED TO EXPAND THIS AREA OF FREEZING PRECIP SWD THOUGH AS FORECAST SOUNDINGS CONTINUE TO SHOW TEMPS STAYING ABOVE 32F FOR NOW. A FAIRLY MESSY WEATHER PATTERN LOOKS ON TAP FOR THE WEEKEND AS THE OVERRUNNING PATTERN LINGERS AND GETS AIDED BY SFC LOW DEVELOPMENT OVER THE WRN GULF. THE PRECIP SHOULD GRADUALLY DIMINISH INTO EARLY NEXT WEEK WHEN THE LONGWAVE TROF AXIS PUSHES EWD ACROSS THE CNTL CONUS AND DRY AIR TAKES OVER THROUGH THE COLUMN. THE CANADIAN AIRMASS PROGGED TO SLIP SWD ACROSS THE WRN/CNTL CONUS WILL MAINTAIN COOL TEMPS THROUGH MID-WEEK. RAIN CHANCES RETURN VERY LATE IN THE FORECAST PERIOD AS A STRONG SHORTWAVE CROSSES THE REGION AND WORKS IN CONCERT WITH PROGGED COASTAL TROF DEVELOPMENT. MARINE... EXTENDED THE DENSE FOG ADVISORY FOR VERMILION BAY/NEAR SHORE WATERS EAST OF INTRACOASTAL CITY TO 15Z AS VERY LOW VISIBILITIES WILL REMAIN A THREAT UNTIL THE FRONT PASSES THIS AREA. ALSO ADDED CAUTION HEADLINES TO SABINE/CALCASIEU LAKES FOR THIS AFTERNOON AS NRLY WINDS ARE EXPECTED TO INCREASE TO THE 15-20 KNOT RANGE. OTHERWISE SCA CONDITIONS ARE EXPECTED TO DEVELOP THROUGH THE AFTERNOON AND EVENING ON THE COASTAL WATERS AS STRONG OFFSHORE DEVELOPS IN WAKE OF THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... KLCH 50 36 43 35 / 70 30 50 40 KBPT 47 36 44 35 / 60 30 50 40 KAEX 43 32 41 34 / 90 30 50 50 KLFT 50 36 44 38 / 70 30 50 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST SATURDAY FOR COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM-WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT 20 NM-WATERS FROM CAMERON LA TO HIGH ISLAND TX FROM 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM-WATERS FROM INTRACOASTAL CITY TO CAMERON LA FROM 20 TO 60 NM. SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR SABINE LAKE. SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR CALCASIEU LAKE. SMALL CRAFT EXERCISE CAUTION FROM 3 PM CST THIS AFTERNOON THROUGH SATURDAY AFTERNOON FOR VERMILION BAY. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 PM EST SAT DEC 7 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 DEEP TROUGHING ORIENTED FROM EASTERN CANADA ACROSS THE GREAT LAKES AND WEST TO THE SOUTHWEST CONUS IS REINFORCED THROUGHOUT THE UPCOMING WEEK. COLD AIRMASS MAY FINALLY MAY START TO RELAX BY NEXT WEEKEND AS FLOW ALOFT BECOMES MORE ZONAL. FLOW PATTERN THIS WEEK REMAINS ACTIVE ACROSS THE UPPER LAKES. A COUPLE OF SYSTEMS WILL CROSS THE AREA WITH WIDESPREAD SYSTEM SNOWS. MOST SIGNIFICANT OF THESE WILL OCCUR SUNDAY NIGHT AS SHORTWAVE/PV ANAMOLY CROSSING NEVADA/UTAH THIS AFTN/EVENING HEADS OUT INTO CNTRL PLAINS SUNDAY AFTN THEN LIFTS ACROSS UPPER GREAT LAKES SUNDAY NIGHT. SLIGHT WARM AIR ADVECTION...RELATIVE TERM IN THIS AIRMASS...OCCURS OVER SOUTH CENTRAL AND EASTERN CWA SUNDAY EVENING WITH PVA/DEEP LAYER FORCING THROUGH REST OF NIGHT. CROSS-SECTIONS INDICATE VERY SHALLOW FGEN FORCING BLO H9...MAINLY SOUTH AND EAST. MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV TO RESULT IN HEAVIER BANDED SNOW THOUGH. ENHANCEMENT TO SYSTEM SNOW MAY OCCUR NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE/E WINDS IN LOW-LEVELS WITH TEMPS AT INVERSION TOP OF H85 AROUND -10C /LK MICHIGAN WATER TEMPS ARE AROUND +5C/. TRICK IS HOW LONG FAVORABLE WIND DIRECTION PERSISTS AND WHETHER THERE IS TOO MUCH SHEAR IN LAKE CONVECTIVE LAYER TO OFFSET THIS. EXPECT GENERAL 2-4" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S 17-19:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEMED TOUGHER TO ACHIEVE AS BULK OF LIFT WILL BE OCCURRING AT TEMPS LESS THAN -20C. SLR/S WILL PROBABLY BE EVEN LOWER HEADING FARTHER NORTH INTO UPR MICHIGAN...SO SNOW AMOUNTS OF AN INCH MAYBE TWO ARE EXPECTED CLOSER TO LK SUPERIOR SHORE. ISSUED WINTER WEATHER ADVY FOR THE SYSTEM SNOW. BASED ON SREF PLUMES AND FCST POPS...VALID TIME OF ADVY FAR SCNTRL WILL START LATE SUNDAY AFTN AND GO THROUGH DAYBREAK ON MONDAY. ADVY FOR ZONES TO THE EAST WILL START AND END A FEW HOURS LATER. LOW PRESSURE SYSTEM LIFTS TO NORTHEAST OF LK SUPERIOR BY 18Z ON MONDAY AND THIS WILL USHER IN ANOTHER RETURN TO THE COLD AND WINDY WEATHER THAT OCCURRED LATE THIS LAST WEEK INTO TODAY. AND YES...LAKE EFFECT SNOWS...HEAVY AT TIMES...WILL RAMP UP AGAIN IN THE AREAS FAVORED BY WNW-W FLOW. SO...ONCE AGAIN...KEWEEENAW PENINSULA WILL BE IN LINE FOR HEAVY LK EFFECT SNOWS. SOUNDINGS IN WAKE OF THE LOW PRESSURE INDICATE MOIST/UNSTABLE PROFILE TO H7 WITH SHARP CONVERGENCE DEVELOPING ACROSS KEWEENAW BY MID MORNING MONDAY AND CONTINUING THROUGH AT LEAST LATE EVENING ON MONDAY NIGHT. SIMILAR TO THURSDAY...IF WESTERLY FLOW CAN PERSIST IN ONE AREA...LEADING TO STRONG CONVERGENCE...FOOT PLUS AMOUNTS WILL BE POSSIBLE ACROSS CNTRL HOUGHTON COUNTY... AFFECTING PAINESDALE...ATLANTIC MINE...HOUGHTON AND HANCOCK AND POSSIBLY AS FAR NORTH AS CALUMET AND MOHAWK. LAKE EFFECT HEADLINES ARE RUNNING THEIR COURSE CURRENTLY...SO DID NOT WANT TO PUT UP ANOTHER LK EFFECT SNOW WATCH AT THIS TIME. WILL LET MID SHIFT ASSESS THIS POTENTIAL. MAIN ISSUE AWAY FM THE INCREASING LK EFFECT BY MONDAY AFTN WILL BE ANOTHER BLAST OF COLD TEMPS AND LOWERING WIND CHILL READINGS. DOES APPEAR THAT AS STRONGER SHORTWAVE/PRETTY DECENT AREA OF H7-H5 Q-VECTOR CONVERGENCE ARRIVES LATER MONDAY NIGHT...BLYR WINDS BACK SW ENOUGH TO DISRUPT HEAVIER SNOW ON THE KEWEENAW. THIS MAY PROVIDE A GOOD BREAK POINT FOR WHATEVER HEADLINE IS ISSUED FOR MONDAY AND MONDAY EVENING...THOUGH THERE IS A CHANCE THE HEAVIER SNOW BANDS WILL JUST MAKE INTO KEWEENAW COUNTY BEFORE STALLING OUT. TOUGH TO SAY AT THIS POINT. SOUNDINGS ELSEHWERE INDICATE ENOUGH MOISTENING AND LIFT TO INCREASE POPS FOR THE SYSTEM...ESPECIALLY NORTH HALF. SNOW AMOUNTS FM THE SYSTEM WILL BE ON THE LGT SIDE...LESS THAN AN INCH MAINLY. OTHER IMPACT FM THE SHORTWAVE WILL BE FOR TEMPS TO TRY TO RISE SOME LATER MONDAY NIGHT AS THE WINDS INCREASE. THIS MAKES FOR TRICKY WIND CHILL FORECAST. CURRENT FCST FOR WINDS AND TEMPS DOES SUGGEST THAT WESTERN HALF OF CWA MAY SEE WIND CHILL CRITERIA BE MET AT TIMES ON MONDAY NIGHT INTO TUESDAY MORNING. LAST IMPACT FROM THE SYSTEM WILL BE TO PUSH STRONGER SFC TROUGH SOUTH ACROSS LK SUPERIOR RESULTING IN MORE OF A NW WIND IN BLYR FOR TUESDAY/TUESDAY NIGHT. USED LK EFFECT CLIMATOLOGY POPS TO BRING HIGHER POPS TO AREAS FAVORED BY WNW FLOW SUCH AS ONTONAGON COUTNY AND ALSO IN THE EASTERN CWA...MAINLY EAST OF MUNISING AND TO THE NORTH OF NEWBERRY. IN WAKE OF THE TROUGH PASSAGE...COLDEST AIR OF WEEK POURS ACROSS WITH H85 TEMPS DOWN TO AROUND -25C TUESDAY NIGHT INTO WEDNESDAY. MAY HAVE MORE WIND CHILL ISSUES TUESDAY NIGHT INTO WEDNESDAY AS INLAND TEMPS FALL BLO ZERO AND WINDS STAY UP BEHIND THE TROUGH. COLDEST DAY OF THE WEEK FOR WEDNESDAY WITH MAX TEMPS OVER INLAND WEST POSSIBLY STAYING AT OR BLO ZERO THE ENTIRE DAY. COLDEST NIGHT OF THE WEEK LIKELY ON WEDNESDAY NIGHT. AS WINDS GO CALM MAY SEE MINS LESS THAN 20 BLO ZERO. SLIGHT WARMING TREND FOR LATE THIS WEEK...BUT STILL QUITE A BIT BLO NORMAL FOR DAYTIME HIGHS. WEST/SOUTHWEST FLOW LK EFFECT STAYS IN PLACE ON KEWEENAW THURSDAY BUT THEN SHOULD REORIENT TO MORE NNW-N FLOW AREAS ON FRIDAY AS ANOTHER SFC TROUGH SWINGS ACROSS. MAY SEE SOME SYSTEM SNOW THURSDAY NIGHT INTO FRIDAY AHEAD OF THAT TROUGH BUT THERE ARE SOME TIMING ISSUES THERE STILL...SO WILL JUST HAVE LOW CHANCE POPS FOR NOW. DID BUMP UP THE CONSENSUS POPS FOR THE LK EFFECT AREAS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 637 PM EST SAT DEC 7 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KIWD/KSAW WILL RESULT IN VFR CONDITIONS THRU SUN MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THROUGH EARLY SUN MORNING AS WINDS WILL CONTINUE TO HAVE ENOUGH OF AN ONSHORE COMPONENT. WITH HEAVIER SNOW BANDS LIKELY REMAINING N OF KCMX... EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT. WITH LOSS OF ONSHORE WIND COMPONENT SUN MORNING AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN AND MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 AM EST SUNDAY FOR MIZ003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001. WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002- 004-009>011-084. WINTER WEATHER ADVISORY FROM 7 PM SUNDAY TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
239 PM EST FRI DEC 6 2013 LATEST UPDATE... SYNOPSIS/HYDRO/MARINE .SYNOPSIS... ISSUED AT 238 PM EST FRI DEC 6 2013 THE COLDEST EARLY DECEMBER TEMPERATURES SINCE 2005 ARE EXPECTED. SNOW SHOWERS WILL PREVAIL WITH 1 TO 2 INCHES OF ACCUMULATION NEAR AND WEST OF US-131 THROUGH SATURDAY EVENING. FROM SUNDAY NIGHT INTO MONDAY EXPECT A GENERAL SNOWFALL OF 1 TO 3 INCHES. LAKE EFFECT SNOW SHOWERS ARE EXPECTED MIDDAY MONDAY THROUGH THURSDAY WITH SIGNIFICANT ACCUMULATIONS POSSIBLE WEST OF US-131. && .UPDATE... ISSUED AT 1128 AM EST FRI DEC 6 2013 I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV 1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY. I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES. ELSEWHERE AND OTHERWISE THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE SHOWING GOOD RUN TO RUN CONSISTENCY. LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY OVER LAKE INSTABILITY. WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER 20S AFTER WE LOSE A FEW DEGREES THIS MORNING. WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND. WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH SOME CLEARING LIKELY. THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S. TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF SNOW ACCUMULATION. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF. NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN. THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS. COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND MOISTURE IS RATHER SHALLOW/LIMITED. THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY AS SURFACE RIDGING BUILDS IN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1233 PM EST FRI DEC 6 2013 A MIX OF VFR AND MVFR CEILINGS CAN BE EXPECTED OVER THE NEXT 24 HOURS. THE BULK OF THE MVFR WILL BE DOWN WIND FROM LAKE MICHIGAN... WITH NW OR WNW FLOW. THE MVFR CONDITIONS SHOULD BE MOST PERSISTENT AT AZO...WITH VFR AND OCCASIONAL MVFR EXPECTED FOR THE REMAINDER OF THE TAF SITES. THERE WILL ALSO BE LIGHT SNOW SHOWERS COMING OFF THE LAKE. MOST VSBYS WILL BE REDUCED INTO THE MVFR RANGE...HOWEVER A FEW ISOLATED SNOW SHOWERS MAY BRING VSBYS DOWN INTO THE IFR RANGE. ONCE AGAIN...WITH THE NW FLOW...AZO SHOULD SEE MORE FREQUENT SNOW SHOWERS THEN THE REST OF THE TAF SITES. THE HIGHEST IMPACT SNOW SHOWERS SHOULD OCCUR FROM ROUGHLY 04Z TO 14Z SATURDAY WHEN THE BEST LOW LEVEL MOISTURE IS REALIZED. && .MARINE... ISSUED AT 238 PM EST FRI DEC 6 2013 LITTLE REASON TO CHANGE OUR FORECAST OR HEADLINES AT THIS POINT. NORTHWEST WINDS OF 15 TO 25 KNOTS WILL KEEP WAVES IN THE 4 TO 7 FOOT RANGE INTO SATURDAY BEFORE WINDS DIMINISH LATE IN THE DAY ALLOWING WAVE HEIGHTS TO ALSO DIMINISH. && .HYDROLOGY... ISSUED AT 238 PM EST FRI DEC 6 2013 WE WILL CONTINUE TO MONITOR THE ICE JAM THREAT AS THE COLD WEATHER PERSISTS. THE GENERAL SNOWFALL SUNDAY NIGHT INTO MONDAY MAY FACILITATE ICE FORMATION ON AREA RIVERS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...WDM SHORT TERM...NJJ LONG TERM...MEADE AVIATION...JK HYDROLOGY...WDM MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1233 PM EST FRI DEC 6 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 332 AM EST FRI DEC 6 2013 COLD AIR IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND. THERE WILL BE SOME LAKE EFFECT SNOW SHOWERS THROUGH SATURDAY. NO SIGNIFICANT ACCUMULATIONS ARE EXPECTED. MOST OF THE AREA SHOULD SEE LIGHT SNOW ACCUMULATIONS LATE SUNDAY THROUGH MONDAY AS A WAVE OF LOW PRESSURE MOVES THROUGH THE AREA. COLDER AIR WILL MOVE IN DURING THE EARLY PORTION OF NEXT WEEK. CONDITIONS LOOK A BIT MORE FAVORABLE FOR LAKE EFFECT SNOW ACCUMULATIONS NEXT WEEK...ESPECIALLY ACROSS THE WESTERN HALF OF THE AREA. && .UPDATE... ISSUED AT 1128 AM EST FRI DEC 6 2013 I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV 1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY. I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES. ELSEWHERE AND OTHERWISE THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE SHOWING GOOD RUN TO RUN CONSISTENCY. LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY OVER LAKE INSTABILITY. WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER 20S AFTER WE LOSE A FEW DEGREES THIS MORNING. WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND. WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH SOME CLEARING LIKELY. THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S. TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF SNOW ACCUMULATION. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF. NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN. THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS. COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND MOISTURE IS RATHER SHALLOW/LIMITED. THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY AS SURFACE RIDGING BUILDS IN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1233 PM EST FRI DEC 6 2013 A MIX OF VFR AND MVFR CEILINGS CAN BE EXPECTED OVER THE NEXT 24 HOURS. THE BULK OF THE MVFR WILL BE DOWN WIND FROM LAKE MICHIGAN... WITH NW OR WNW FLOW. THE MVFR CONDITIONS SHOULD BE MOST PERSISTENT AT AZO...WITH VFR AND OCCASIONAL MVFR EXPECTED FOR THE REMAINDER OF THE TAF SITES. THERE WILL ALSO BE LIGHT SNOW SHOWERS COMING OFF THE LAKE. MOST VSBYS WILL BE REDUCED INTO THE MVFR RANGE...HOWEVER A FEW ISOLATED SNOW SHOWERS MAY BRING VSBYS DOWN INTO THE IFR RANGE. ONCE AGAIN...WITH THE NW FLOW...AZO SHOULD SEE MORE FREQUENT SNOW SHOWERS THEN THE REST OF THE TAF SITES. THE HIGHEST IMPACT SNOW SHOWERS SHOULD OCCUR FROM ROUGHLY 04Z TO 14Z SATURDAY WHEN THE BEST LOW LEVEL MOISTURE IS REALIZED. && .MARINE... ISSUED AT 332 AM EST FRI DEC 6 2013 WE ARE EXTENDING THE SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE THROUGH 06Z SUN WITH THIS FCST PACKAGE. WINDS WILL COME DOWN TO AROUND 15 TO 20 KNOTS TODAY AND REMAIN THERE THROUGH SAT. THE ONSHORE FLOW AND UNSTABLE CONDITIONS WITH THE COLD AIR COMING IN OVER THE LAKE WILL KEEP WAVES ABOVE 4 FEET THROUGH SAT. THERE SHOULD BE A BREAK SAT NIGHT AND EARLY SUN. && .HYDROLOGY... ISSUED AT 332 AM EST FRI DEC 6 2013 THE ONLY CONCERN WITH HYDROLOGY REMAINS THE THREAT FOR ICE DEVELOPMENT OVER THE NEXT WEEK. ARCTIC COLD AIR EXPECTED OVER THE AREA THROUGH MOST OF THE NEXT WEEK WILL HELP ICE DEVELOPMENT. AS THE ICE DEVELOPS...WE WILL BE MONITORING THE POTENTIAL FOR ICE JAMS TO FORM. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...JK HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1156 AM EST FRI DEC 6 2013 .AVIATION... //DISCUSSION... AN MVFR STRATUS DECK HAS BEEN ON THE DOORSTEP OF MBS FOR THE LAST HOUR. THE COMBINATION OF THE LOW LEVEL MOISTURE FLUX OFF LAKE MICHIGAN AND THE DEPTH OF THE LOW LEVEL INVERSION SHOULD SUSTAIN SOME DEGREE OF LOW CLOUDS INTO AT LEAST MBS THIS AFTERNOON AND EVENING. THE MAIN LIMITING FACTOR WILL BE THE VERY DRY ARCTIC AIR NOW ENVELOPING THE REGION. THE INCREASING RESPONSE NOTED OFF LAKE MICHIGAN MAY ALLOW SOME OF THE STRATO CU TO PERIODICALLY ADVANCE ACROSS FNT AND PTK THIS EVENING. FOR DTW...THERE IS GROWING CONFIDENCE THAT POOR MOISTURE QUALITY WILL KEEP ANY LIGHT SNOW/FLURRIES WELL SOUTH OF METRO THIS EVENING. ALTHOUGH STRATO CU FROM THE WEST SIDE OF THE STATE WILL ATTEMPT TO PUSH TOWARD THE EAST...THE DEGREE OF LOW LEVEL DRY AIR AND SLIGHT DOWNSLOPE COMPONENT INTO METRO UNDER A WNW FLOW SUPPORTS NOTHING MORE THAN SCT MVFR CLOUD BASES THIS EVENING. //DTW THRESHOLD THREATS... * LOW CONFIDENCE ON CEILINGS BELOW 5000 FT THIS EVENING AND OVERNIGHT. && .PREV DISCUSSION...ISSUED 1008 AM EST FRI DEC 6 2013 UPDATE... THE THICK CANOPY OF MID/HIGH CLOUDS AND WEAK LOW LEVEL COLD AIR ADVECTION THROUGH THE AFTERNOON WILL INHIBIT MUCH IF ANY DIURNAL RESPONSE. THIS WILL SUPPORT A MINOR DOWNWARD ADJUSTMENT TO TEMPS THIS AFTERNOON. THE DEPTH OF THE COLD AIR HAS BEEN INCREASING OVER THE WESTERN GREAT LAKES WHICH IS LEADING TO A BETTER RESPONSE OFF LAKE MI. THE 12Z DTX SOUNDING SHOWED A DEEP INVERSION BASED NEAR 920MB. THIS SHOULD ALLOW A GOOD DUCT FOR THE WESTWARD EXPANSION OF LAKE STRATO CU. RAP SOUNDINGS ON BUFKIT SUGGEST SUPERSATURATION WITH RESPECT TO ICE NEAR THE INVERSION LEVEL. SO IT SHOULD NOT BE DIFFICULT TO GENERATE SOME FLURRIES FROM THESE LOWER BASED CLOUDS. THIS WILL BE MORE PROBABLE ACROSS THE SAGINAW VALLEY AND THUMB GIVEN THE WESTERLY FLOW. FARTHER SOUTH...THE LOW LEVEL FLOW BECOMES HIGHLY DIVERGENT WHICH MAY KEEP THE LOW CLOUDS CONFINED TO WRN LOWER MI THROUGH THE AFTERNOON. PREV DISCUSSION...ISSUED 356 AM EST FRI DEC 6 2013 SHORT TERM...TODAY AND TONIGHT THE WEATHER FOR SOUTHEASTERN MICHIGAN WILL BE INFLUENCED BY A BAROCLINIC ZONE THAT IS IN PLACE FROM THE EASTERN GREAT LAKES THROUGH MUCH OF THE OHIO RIVER VALLEY. THE FRONTAL BOUNDARY WILL BECOME QUASI-STATIONARY TODAY AS THE VERY STRONG...POLAR JET AXIS OVERHEAD BECOMES FAIRLY STATIC. CHARACTERISTICS OF THE FRONT OFFERED BY CROSS SECTIONS ARE: 1. GRADUALLY SLOPED 2. A DOUBLE GRADIENT STRUCTURE AT ROUGHLY 750 MB AND 550 MB. A WAVE IS EXPECTED TO RIPPLE ALONG THE BAROCLINIC ZONE LATE THIS AFTERNOON AS A LOWER TROPOSPHERIC REFLECTION OF RIGHT ENTRANCE REGION DYNAMICS. OVERALL PRECIPITATION CHANCES WILL BE NEAR ZERO FOR MUCH OF THE CWA WITH CHANCES VERY LOW ACROSS MONROE COUNTY. THE REASON IS ANALYSES OF LOW TO MID TROPOSPHERIC -DIV AND DEFORMATION ADVERTISE VERY LITTLE FORCING. IN ADDITION...CROSS SECTIONS SUPPORT SUBSIDENCE THIS AFTERNOON BETWEEN THE 750 MB AND 550 MB GRADIENTS ALONG WITH RELATIVELY HIGH STATIC STABILITY THROUGH A GOOD CHUNK OF THE COLUMN. A DRY LAYER BELOW THE 750MB GRADIENT WILL PROVIDE AN EVAPORATION BUFFER. IN THE SPIRIT OF CONTINUITY...CONTINUED TO INCLUDE A LOW CHANCE POP OF LIGHT SNOW FOR MONROE COUNTY BETWEEN 21-02Z BUT ANY SNOWFALL...IF ANY...WILL BE NEGLIGIBLE. SOME FORCING VERY HIGH IN COLUMN IS STILL EXPECTED TO OVERLAP SOUTHEASTERN MICHIGAN WHICH SHOULD PROVIDE AN ABUNDANCE OF HIGH CLOUD FOR MUCH OF THE DAYLIGHT HOURS. SLUGGISH MOVEMENT OF THE FRONT TODAY WILL GIVE SOME POTENTIAL AT AFTERNOON HIGHS DESPITE THE CLOUDS. FREEZING MARK SOUTH...TO MIDDLE 20S NORTH. WIND CHILLS WILL DROP INTO THE TEENS THIS MORNING...THEN STRUGGLE TO CLIMB ABOVE 20 FOR THE AFTERNOON. SUBSIDENCE OCCURRING BEHIND THE WAVE LATE TONIGHT ALONG WITH DRY AIR SHOULD ALLOW CLOUDS TO SCATTER AN HOUR OR TWO BEFORE SUNRISE. TEMPERATURES WILL HAVE THE POTENTIAL TO DROP...LOWS IN THE TEENS WIND CHILLS IN THE SINGLE DIGITS FOR ALL OF SOUTHEASTERN MICHIGAN. LONG TERM...SATURDAY THROUGH THURSDAY HIGH AMPLITUDE MID LEVEL FLOW ANCHORED BY A SPRAWLING LONGWAVE TROUGH WILL REMAIN THE CONTROLLING LARGE SCALE FEATURE WELL INTO NEXT WEEK. THE WEEKEND BEGINS WITH SE MICHIGAN INITIALLY RESIDING ALONG THE EASTERN EXTENSION OF THE MAIN HEIGHT FALL CENTER AND WELL WITHIN THE COLD DOME PERPETUATED BY AN INBOUND 1040 MB ARCTIC HIGH. AMBIENT AIRMASS WILL CARRY A DEEP DRY LAYER ABOVE 900 MB...WHILE A CHECK OF UPSTREAM SOUNDINGS ACROSS LAKE MICHIGAN SHOW A PROFILE ALSO LACKING IN MOISTURE DEPTH WITH SUPPRESSED INVERSION HEIGHTS. THIS WOULD INDICATE THE OPPORTUNITY FOR A LAKE AND/OR DIURNALLY ENHANCED STRATOCU FIELD WILL BE LIMITED. SOME LINGERING EARLY STRATUS MAY EXIST...PARTICULARLY ACROSS THE NORTH WITH THE RESIDUAL MOISTURE SOURCE FROM TODAY PERHAPS SLOWER TO MIX OUT. MAIN STORY WILL BE TEMPERATURES...WITH EVEN A HIGH DEGREE OF INSOLATION STRUGGLING TO MODERATE A THERMAL PROFILE CARRYING 925 MB TEMPERATURES IN THE -11 TO -12C RANGE. THIS WILL TRANSLATE INTO HIGHS OF LOWER TO MIDDLE 20S...OR A GOOD 15 DEGREE BELOW EARLY DECEMBER NORMS. THE EXISTING SURFACE RIDGING AND DEEP DRY LAYER WILL PROMOTE A GOOD RADIATIONAL COOLING RESPONSE SATURDAY NIGHT. A GRADUALLY INCREASING CIRRUS SHIELD WILL BE THE ONE POSSIBLE DISRUPTION TO REALIZING THE FULL POTENTIAL. OVERALL STILL LOOKING AT LOWS IN THE TEENS...A FEW SINGLE DIGIT READINGS NOT OUT OF THE QUESTION IN THE COLDEST LOCALES. CONDITIONS INTO SUNDAY REMAIN DEFINED BY THE PRESENCE OF A COLD/DRY ENVIRONMENT...LOW LEVEL FLOW FLIPPING TO EASTERLY WITH THE ARCTIC HIGH SLOWLY EASING EASTWARD. HIGHS AGAIN IN THE 20S...EFFECTIVELY CONTAINED BY A MORE CONCERTED INCREASE IN HIGH CLOUD. FOCUS INTO SUNDAY EVENING/NIGHT THEN TURNS TO A WELL DEFINED PV ANOMALY WORKING THROUGH THE TROUGH BASE. THIS WAVE WILL SHEAR INTO THE PREVAILING SOUTHWESTERLIES ORIENTED FROM THE CENTRAL PLAINS INTO THE GREAT LAKES THROUGH THE LATTER HALF OF THE WEEKEND. THIS PROCESS WILL PROMPT TWO AREAS OF FOCUS...ONE WITHIN A WING OF EMERGING ISENTROPIC ASCENT AND MOISTURE TRANSPORT ORIGINATING OUT OF THE WESTERN GULF...AND A SECOND ACCOMPANYING THE PRIMARY REGION OF FORCED ASCENT CONTAINED WITHIN THE MAIN HEIGHT FALL CENTER AND ALONG THE DEVELOPING WEAK SURFACE WAVE AND FRONTAL CIRCULATION EJECTING OUT OF THE PLAINS. THE OVERALL UPPER JET POSITIONING WOULD TEND TO DIRECT THE BULK OF THE GULF ORIGINATING MOISTURE AND ATTENDANT WEAK ASCENT TO OUR SOUTHEAST. IT REMAINS PLAUSIBLE FOR SOUTHERN SECTIONS OF SOUTHEAST MICHIGAN TO RECEIVE A GLANCING SHOT ALONG THE WESTERN EDGE SUNDAY EVENING. WEAK SURFACE WAVE THEN LIFTS THROUGH LOWER MICHIGAN SUNDAY NIGHT...DISPLACED SOUTHEAST OF THE MAIN STRIPE OF DCVA AND DEFORMATION FORCING SHIFTING FROM THE UPPER MS VALLEY INTO THE U.P. THIS WILL LEAVE SE MICHIGAN UNDER A BROADER LOOKING PERIOD OF FORCING...STILL SUFFICIENT TOWARD GENERATING A FEW HUNDREDTHS OF QPF SUNDAY NIGHT. A SUB-FREEZING THERMAL PROFILE THROUGHOUT WILL SUPPORT ALL SNOW...ALTHOUGH THE PROFILE WILL BE WARMING WITH TIME...EFFECTIVELY REDUCING POTENTIAL SNOWFALL RATIOS. A GENERAL EASTWARD MIGRATION OF THE MEAN LONGWAVE TROUGH WILL DIRECT A SERIES SHORTWAVES OF SIBERIAN ORIGIN THROUGH THE GREAT LAKES DURING THE EARLY AND MID WEEK PERIOD. THIS WILL RESULT IN AN EXTENDED STRETCH OF WELL BELOW NORMAL TEMPERATURES AS ARCTIC AIR TAKES FIRM RESIDENCE THROUGHOUT THE WEEK. MARINE... WESTERLY WINDS WILL DIMINISH SLIGHTLY TODAY AND TONIGHT AS THE PRESSURE GRADIENT EASES BEHIND LOW PRESSURE LIFTING INTO QUEBEC. THIS WILL RESULT IN A LOWER WAVE CONDITIONS THROUGH THIS TIME. COLDER AIR MOVING ACROSS THE WATERS WILL MAINTAIN WIND SPEEDS IN THE 15 TO 20 KNOT RANGE ACROSS NORTHERN PORTIONS OF LAKE HURON. SLIGHT INCREASE IN WINDS EARLY SATURDAY WILL BRING GUSTS JUST SHY OF GALES ACROSS NORTHERN LAKE HURON. STRONG HIGH PRESSURE WILL THEN TAKE CONTROL SATURDAY NIGHT AND SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SC UPDATE.......SC SHORT TERM...CB LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1128 AM EST FRI DEC 6 2013 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 332 AM EST FRI DEC 6 2013 COLD AIR IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND. THERE WILL BE SOME LAKE EFFECT SNOW SHOWERS THROUGH SATURDAY. NO SIGNIFICANT ACCUMULATIONS ARE EXPECTED. MOST OF THE AREA SHOULD SEE LIGHT SNOW ACCUMULATIONS LATE SUNDAY THROUGH MONDAY AS A WAVE OF LOW PRESSURE MOVES THROUGH THE AREA. COLDER AIR WILL MOVE IN DURING THE EARLY PORTION OF NEXT WEEK. CONDITIONS LOOK A BIT MORE FAVORABLE FOR LAKE EFFECT SNOW ACCUMULATIONS NEXT WEEK...ESPECIALLY ACROSS THE WESTERN HALF OF THE AREA. && .UPDATE... ISSUED AT 1128 AM EST FRI DEC 6 2013 I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV 1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY. I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES. ELSWHERE AND OTHERWISE THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE SHOWING GOOD RUN TO RUN CONSISTENCY. LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY OVER LAKE INSTABILITY. WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER 20S AFTER WE LOSE A FEW DEGREES THIS MORNING. WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND. WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH SOME CLEARING LIKELY. THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S. TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF SNOW ACCUMULATION. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 332 AM EST FRI DEC 6 2013 THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF. NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN. THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS. COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND MOISTURE IS RATHER SHALLOW/LIMITED. THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY AS SURFACE RIDGING BUILDS IN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 658 AM EST FRI DEC 6 2013 MVFR CIGS AROUND 2500 FT AND A FEW LIGHT LAKE EFFECT SNOW SHOWERS ARE ANTICIPATED TODAY. FOR THE MOST PART NO SIGNIFICANT LENGTHY REDUCTIONS TO VSBYS ARE EXPECTED... BUT THERE MAY BE TIMES WHEN IT DIPS DOWN TO 4-6 MILES. LAN AND JXN PROBABLY WILL NOT SEE THE MVFR CIGS AND FLURRIES TODAY... BUT THEY COULD SPREAD INLAND TONIGHT. KMKG AND KAZO MAY SEE SOME BETTER SNOW SHOWERS DEVELOPING LATER TONIGHT WHICH COULD LOWER VSBYS POTENTIALLY INTO IFR CATEGORY AT TIMES. DID NOT INCLUDE THIS THREAT IN THE TAFS YET HOWEVER AS CONFIDENCE IS CURRENTLY TOO LOW. && .MARINE... ISSUED AT 332 AM EST FRI DEC 6 2013 WE ARE EXTENDING THE SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE THROUGH 06Z SUN WITH THIS FCST PACKAGE. WINDS WILL COME DOWN TO AROUND 15 TO 20 KNOTS TODAY AND REMAIN THERE THROUGH SAT. THE ONSHORE FLOW AND UNSTABLE CONDITIONS WITH THE COLD AIR COMING IN OVER THE LAKE WILL KEEP WAVES ABOVE 4 FEET THROUGH SAT. THERE SHOULD BE A BREAK SAT NIGHT AND EARLY SUN. && .HYDROLOGY... ISSUED AT 332 AM EST FRI DEC 6 2013 THE ONLY CONCERN WITH HYDROLOGY REMAINS THE THREAT FOR ICE DEVELOPMENT OVER THE NEXT WEEK. ARCTIC COLD AIR EXPECTED OVER THE AREA THROUGH MOST OF THE NEXT WEEK WILL HELP ICE DEVELOPMENT. AS THE ICE DEVELOPS...WE WILL BE MONITORING THE POTENTIAL FOR ICE JAMS TO FORM. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1008 AM EST FRI DEC 6 2013 .UPDATE... THE THICK CANOPY OF MID/HIGH CLOUDS AND WEAK LOW LEVEL COLD AIR ADVECTION THROUGH THE AFTERNOON WILL INHIBIT MUCH IF ANY DIURNAL RESPONSE. THIS WILL SUPPORT A MINOR DOWNWARD ADJUSTMENT TO TEMPS THIS AFTERNOON. THE DEPTH OF THE COLD AIR HAS BEEN INCREASING OVER THE WESTERN GREAT LAKES WHICH IS LEADING TO A BETTER RESPONSE OFF LAKE MI. THE 12Z DTX SOUNDING SHOWED A DEEP INVERSION BASED NEAR 920MB. THIS SHOULD ALLOW A GOOD DUCT FOR THE WESTWARD EXPANSION OF LAKE STRATO CU. RAP SOUNDINGS ON BUFKIT SUGGEST SUPERSATURATION WITH RESPECT TO ICE NEAR THE INVERSION LEVEL. SO IT SHOULD NOT BE DIFFICULT TO GENERATE SOME FLURRIES FROM THESE LOWER BASED CLOUDS. THIS WILL BE MORE PROBABLE ACROSS THE SAGINAW VALLEY AND THUMB GIVEN THE WESTERLY FLOW. FARTHER SOUTH...THE LOW LEVEL FLOW BECOMES HIGHLY DIVERGENT WHICH MAY KEEP THE LOW CLOUDS CONFINED TO WRN LOWER MI THROUGH THE AFTERNOON. && .AVIATION...ISSUED 646 AM EST FRI DEC 6 2013 //DISCUSSION... DESPITE THE SURFACE FRONT PUSHED UP AGAINST THE APPALACHIAN CHAIN...A GRADUAL SLOPE TO THIS FEATURE PLACES THE MIDLEVEL PORTION OF THE FRONT OVER SOUTHEASTERN MICHIGAN. THIS BOUNDARY WILL PROVIDE PLENTY IN THE WAY OF HIGH CLOUD TODAY. A WAVE IS EXPECTED TO RIDE ALONG THE BOUNDARY REACHING THE AREA VERY LATE IN THE AFTERNOON AND EARLY EVENING. DRY AIR IN THE LOW LEVELS AND A RELATIVELY HIGH AMOUNT OF STABILITY WILL MAKE IT DIFFICULT TO SEE ANY PRECIPITATION. THE ONLY POTENTIAL FOR ANY FLURRIES TO FALL WOULD BE KDTW/KYIP/KDET. BASES WILL TRY TO LOWER WITH THIS FORCING...REMAINING AT OR ABOVE 4000 FT. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS AT OR BELOW 5000 FT THIS AFTERNOON. && .PREV DISCUSSION...ISSUED 356 AM EST FRI DEC 6 2013 SHORT TERM...TODAY AND TONIGHT THE WEATHER FOR SOUTHEASTERN MICHIGAN WILL BE INFLUENCED BY A BAROCLINIC ZONE THAT IS IN PLACE FROM THE EASTERN GREAT LAKES THROUGH MUCH OF THE OHIO RIVER VALLEY. THE FRONTAL BOUNDARY WILL BECOME QUASI-STATIONARY TODAY AS THE VERY STRONG...POLAR JET AXIS OVERHEAD BECOMES FAIRLY STATIC. CHARACTERISTICS OF THE FRONT OFFERED BY CROSS SECTIONS ARE: 1. GRADUALLY SLOPED 2. A DOUBLE GRADIENT STRUCTURE AT ROUGHLY 750 MB AND 550 MB. A WAVE IS EXPECTED TO RIPPLE ALONG THE BAROCLINIC ZONE LATE THIS AFTERNOON AS A LOWER TROPOSPHERIC REFLECTION OF RIGHT ENTRANCE REGION DYNAMICS. OVERALL PRECIPITATION CHANCES WILL BE NEAR ZERO FOR MUCH OF THE CWA WITH CHANCES VERY LOW ACROSS MONROE COUNTY. THE REASON IS ANALYSES OF LOW TO MID TROPOSPHERIC -DIV AND DEFORMATION ADVERTISE VERY LITTLE FORCING. IN ADDITION...CROSS SECTIONS SUPPORT SUBSIDENCE THIS AFTERNOON BETWEEN THE 750 MB AND 550 MB GRADIENTS ALONG WITH RELATIVELY HIGH STATIC STABILITY THROUGH A GOOD CHUNK OF THE COLUMN. A DRY LAYER BELOW THE 750MB GRADIENT WILL PROVIDE AN EVAPORATION BUFFER. IN THE SPIRIT OF CONTINUITY...CONTINUED TO INCLUDE A LOW CHANCE POP OF LIGHT SNOW FOR MONROE COUNTY BETWEEN 21-02Z BUT ANY SNOWFALL...IF ANY...WILL BE NEGLIGIBLE. SOME FORCING VERY HIGH IN COLUMN IS STILL EXPECTED TO OVERLAP SOUTHEASTERN MICHIGAN WHICH SHOULD PROVIDE AN ABUNDANCE OF HIGH CLOUD FOR MUCH OF THE DAYLIGHT HOURS. SLUGGISH MOVEMENT OF THE FRONT TODAY WILL GIVE SOME POTENTIAL AT AFTERNOON HIGHS DESPITE THE CLOUDS. FREEZING MARK SOUTH...TO MIDDLE 20S NORTH. WIND CHILLS WILL DROP INTO THE TEENS THIS MORNING...THEN STRUGGLE TO CLIMB ABOVE 20 FOR THE AFTERNOON. SUBSIDENCE OCCURRING BEHIND THE WAVE LATE TONIGHT ALONG WITH DRY AIR SHOULD ALLOW CLOUDS TO SCATTER AN HOUR OR TWO BEFORE SUNRISE. TEMPERATURES WILL HAVE THE POTENTIAL TO DROP...LOWS IN THE TEENS WIND CHILLS IN THE SINGLE DIGITS FOR ALL OF SOUTHEASTERN MICHIGAN. LONG TERM...SATURDAY THROUGH THURSDAY HIGH AMPLITUDE MID LEVEL FLOW ANCHORED BY A SPRAWLING LONGWAVE TROUGH WILL REMAIN THE CONTROLLING LARGE SCALE FEATURE WELL INTO NEXT WEEK. THE WEEKEND BEGINS WITH SE MICHIGAN INITIALLY RESIDING ALONG THE EASTERN EXTENSION OF THE MAIN HEIGHT FALL CENTER AND WELL WITHIN THE COLD DOME PERPETUATED BY AN INBOUND 1040 MB ARCTIC HIGH. AMBIENT AIRMASS WILL CARRY A DEEP DRY LAYER ABOVE 900 MB...WHILE A CHECK OF UPSTREAM SOUNDINGS ACROSS LAKE MICHIGAN SHOW A PROFILE ALSO LACKING IN MOISTURE DEPTH WITH SUPPRESSED INVERSION HEIGHTS. THIS WOULD INDICATE THE OPPORTUNITY FOR A LAKE AND/OR DIURNALLY ENHANCED STRATOCU FIELD WILL BE LIMITED. SOME LINGERING EARLY STRATUS MAY EXIST...PARTICULARLY ACROSS THE NORTH WITH THE RESIDUAL MOISTURE SOURCE FROM TODAY PERHAPS SLOWER TO MIX OUT. MAIN STORY WILL BE TEMPERATURES...WITH EVEN A HIGH DEGREE OF INSOLATION STRUGGLING TO MODERATE A THERMAL PROFILE CARRYING 925 MB TEMPERATURES IN THE -11 TO -12C RANGE. THIS WILL TRANSLATE INTO HIGHS OF LOWER TO MIDDLE 20S...OR A GOOD 15 DEGREE BELOW EARLY DECEMBER NORMS. THE EXISTING SURFACE RIDGING AND DEEP DRY LAYER WILL PROMOTE A GOOD RADIATIONAL COOLING RESPONSE SATURDAY NIGHT. A GRADUALLY INCREASING CIRRUS SHIELD WILL BE THE ONE POSSIBLE DISRUPTION TO REALIZING THE FULL POTENTIAL. OVERALL STILL LOOKING AT LOWS IN THE TEENS...A FEW SINGLE DIGIT READINGS NOT OUT OF THE QUESTION IN THE COLDEST LOCALES. CONDITIONS INTO SUNDAY REMAIN DEFINED BY THE PRESENCE OF A COLD/DRY ENVIRONMENT...LOW LEVEL FLOW FLIPPING TO EASTERLY WITH THE ARCTIC HIGH SLOWLY EASING EASTWARD. HIGHS AGAIN IN THE 20S...EFFECTIVELY CONTAINED BY A MORE CONCERTED INCREASE IN HIGH CLOUD. FOCUS INTO SUNDAY EVENING/NIGHT THEN TURNS TO A WELL DEFINED PV ANOMALY WORKING THROUGH THE TROUGH BASE. THIS WAVE WILL SHEAR INTO THE PREVAILING SOUTHWESTERLIES ORIENTED FROM THE CENTRAL PLAINS INTO THE GREAT LAKES THROUGH THE LATTER HALF OF THE WEEKEND. THIS PROCESS WILL PROMPT TWO AREAS OF FOCUS...ONE WITHIN A WING OF EMERGING ISENTROPIC ASCENT AND MOISTURE TRANSPORT ORIGINATING OUT OF THE WESTERN GULF...AND A SECOND ACCOMPANYING THE PRIMARY REGION OF FORCED ASCENT CONTAINED WITHIN THE MAIN HEIGHT FALL CENTER AND ALONG THE DEVELOPING WEAK SURFACE WAVE AND FRONTAL CIRCULATION EJECTING OUT OF THE PLAINS. THE OVERALL UPPER JET POSITIONING WOULD TEND TO DIRECT THE BULK OF THE GULF ORIGINATING MOISTURE AND ATTENDANT WEAK ASCENT TO OUR SOUTHEAST. IT REMAINS PLAUSIBLE FOR SOUTHERN SECTIONS OF SOUTHEAST MICHIGAN TO RECEIVE A GLANCING SHOT ALONG THE WESTERN EDGE SUNDAY EVENING. WEAK SURFACE WAVE THEN LIFTS THROUGH LOWER MICHIGAN SUNDAY NIGHT...DISPLACED SOUTHEAST OF THE MAIN STRIPE OF DCVA AND DEFORMATION FORCING SHIFTING FROM THE UPPER MS VALLEY INTO THE U.P. THIS WILL LEAVE SE MICHIGAN UNDER A BROADER LOOKING PERIOD OF FORCING...STILL SUFFICIENT TOWARD GENERATING A FEW HUNDREDTHS OF QPF SUNDAY NIGHT. A SUB-FREEZING THERMAL PROFILE THROUGHOUT WILL SUPPORT ALL SNOW...ALTHOUGH THE PROFILE WILL BE WARMING WITH TIME...EFFECTIVELY REDUCING POTENTIAL SNOWFALL RATIOS. A GENERAL EASTWARD MIGRATION OF THE MEAN LONGWAVE TROUGH WILL DIRECT A SERIES SHORTWAVES OF SIBERIAN ORIGIN THROUGH THE GREAT LAKES DURING THE EARLY AND MID WEEK PERIOD. THIS WILL RESULT IN AN EXTENDED STRETCH OF WELL BELOW NORMAL TEMPERATURES AS ARCTIC AIR TAKES FIRM RESIDENCE THROUGHOUT THE WEEK. MARINE... WESTERLY WINDS WILL DIMINISH SLIGHTLY TODAY AND TONIGHT AS THE PRESSURE GRADIENT EASES BEHIND LOW PRESSURE LIFTING INTO QUEBEC. THIS WILL RESULT IN A LOWER WAVE CONDITIONS THROUGH THIS TIME. COLDER AIR MOVING ACROSS THE WATERS WILL MAINTAIN WIND SPEEDS IN THE 15 TO 20 KNOT RANGE ACROSS NORTHERN PORTIONS OF LAKE HURON. SLIGHT INCREASE IN WINDS EARLY SATURDAY WILL BRING GUSTS JUST SHY OF GALES ACROSS NORTHERN LAKE HURON. STRONG HIGH PRESSURE WILL THEN TAKE CONTROL SATURDAY NIGHT AND SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....CB SHORT TERM...CB LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
952 PM CST Sat Dec 7 2013 .UPDATE: Issued at 944 PM CST Sat Dec 7 2013 Several narrow snow bands have developed this evening across southwest Missouri in an area of strong mid level frontogenetical forcing and low/mid level warm advection ahead of a short wave moving through the southern plains. Snow is reaching the ground in and there are areas that have a dusting. The latest RAP and HRRR runs increase the forcing and shift it northeastward parallelling I-44 during the overnight hours and into the St. Louis metro area. This seems reasonable based on observed trends. The only question is the coverage and whether a wider more solitary band will evolve or whether it will remain with several narrow bands. At this time I have increased the pops within this corridor but only mentioned scattered snow showers due to the uncertainty in the coverage evolution. Some areas could certainly pick up a dusting to half inch beneath them. If the coverage expands I will probably need to boost pops into the likely category before the evening is over. Glass && .SHORT TERM: (Through Sunday Evening) Issued at 301 PM CST Sat Dec 7 2013 Strong shortwave dipping into the base of the upper level trof across the western CONUS will move across the Four Corners tonight and emerge into the Plains on Sunday morning. Impressive warm advection forecast to develop ahead of the shortwave with light qpf noted on all model guidance to march northeast across the CWA from late tonight through Sunday afternoon. Believe this is one of those high PoP/low QPF events. Precipitation type is not clear cut...as lack of ice crystal formation is noted on model soundings. I also note that there is a steady stream of mid and high level clouds streaming northeast from Texas. Wonder if the ice crystals from the higher clouds will lead to a seeder/feeder situation, ultimately allowing the precipitation to fall as more snow or snow grains rather than freezing drizzle late tonight and tomorrow morning. Tomorrow afternoon the best lift will be moving northeast and the lower atmosphere will be warming so precipitation will likely turn to areas of freezing drizzle that may continue into the evening. Overall believe snowfall amounts will remain under an inch and any freezing drizzle will only produce a light glaze. Will let the evening and overnight shifts take a look at the 00Z model data to determine the need, if any, for headlines on Sunday. CVKING .LONG TERM: (Sunday Night through Next Saturday) Issued at 301 PM CST Sat Dec 7 2013 Cold front will progress southeast across the CWA late Sunday night, reinforcing the cold for the beginning of the work week. Next shortwave moves into the Plains Monday night an CWA will be in a favorable area of synoptic lift provided by the right entrance region of the jet streak to our northeast. This may ultimately provide another chance of light snow south of Interstate 70. Have kept slight chance PoPs at this time. Extended forecast remains dry and cold with cold front passages Wednesday and Friday. CVKING && .AVIATION: (For the 00z TAFs through 00z Sunday Evening) Issued at 541 PM CST Sat Dec 7 2013 Some minor changes in timing to the prev TAFs, but focus remains the approaching precip. Latest guidance suggests precip will begin as SN as it moves in from W to E thru the region. This event still appears to be a high probability, low precip event. By late morning into the afternoon Sun, the top of the cloud deck will start to erode, removing ice crystals, changing the precip over to FZDZ. A lot of uncertainty remains as to when this change will occur and how long the FZDZ will linger into the afternoon. Cigs shud remain in the low end MVFR cat thru much of the afternoon. However, cigs shud drop quickly into IFR cat around sunset as the atmo cools. Specifics for KSTL: Only some minor changes to timing of different cloud deck arrivals. Did introduce FZDZ Sun afternoon with increased confidence of occurrence. However, timing of onset of SN and then change over to FZDZ remains uncertain. IFR cigs are expected as or shortly after precip ends. Tilly && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
630 PM EST SAT DEC 7 2013 .SYNOPSIS... DAMP AND CHILLY WEATHER WILL PERSIST INTO SUNDAY NIGHT BEFORE A WARM FRONT BRINGS A SHORT-LIVED WARMUP MONDAY. A COLD FRONT WILL MOVE THROUGH TUESDAY BRINGING ANOTHER ROUND OF COOLER WEATHER WEDNESDAY THROUGH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 630 PM SATURDAY...THE SURFACE COLD FRONT IS IN THE PROCESS OF STALLING NEAR THE SOUTH CAROLINA/GEORGIA BORDER. OVER WILMINGTON THE COLD AIRMASS IS ABOUT 3000 FEET DEEP...ABOVE WHICH WINDS ARE STILL FROM THE SOUTHWEST AND ORIGINATE FROM THE CENTRAL GULF OF MEXICO. MODELS DIFFER ON THE DEGREE OF ISENTROPIC LIFT OVER THE FRONTAL SURFACE TONIGHT. THE GFS IS THE MOST BULLISH WITH THIS LIFT ALONG THE 295-305K SURFACES (3500-9000 FT AGL) WHILE THE RUC SHOWS THE LEAST AMOUNT OF LIFT. ALL MODELS CRANK OUT AT LEAST A FEW HUNDREDTHS OF AN INCH OF RAIN AREA-WIDE. RECENT RADAR LOOPS SHOW QUITE A BIT OF RAIN UPSTREAM ACROSS CENTRAL AND SOUTHERN SOUTH CAROLINA...THEREFORE I HAVE RAISED FORECAST POPS FOR THE OVERNIGHT PERIOD TO 80-90 PERCENT FOR ALL BUT THE SOUTH CAROLINA BEACHES AND AREAS NEAR THE SANTEE RIVER. CLOUD DEPTH SHOULD BE SUFFICIENT WITH CLOUD BASES LOW ENOUGH TO GUARANTEE OCCASIONAL DRIZZLE EVEN WHEN MEASURABLE RAIN IS NOT FALLING. COMPARED TO THE PAST SEVERAL DAYS OF SUBTROPICAL WEATHER...TONIGHT`S WEATHER IS A HARSH REMINDER OF THE ACTUAL DATE ON THE CALENDAR. AIRMASS ADVECTION IS THE ONLY FACTOR TO CONSIDER FOR LOWS SINCE DENSE CLOUD COVER WILL NEGATE ANY RADIATIONAL COOLING EFFECTS. PREVIOUS FORECAST LOWS RANGING FROM THE UPPER 30S WEST OF I-95 TO THE MID 40S AT THE BEACHES LOOK REASONABLE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...A DARK AND DREARY SUNDAY ON TAP AS SHALLOW WEDGE OF CHILLY AIR REMAINS ENTRENCHED ALONG THE EAST FACE OF THE APPALACHIANS. HIGH TEMPERATURES WILL REMAIN STUCK IN THE 40S YET IT WILL BE 60 DEGREES 2500 FT ABOVE THE SURFACE. THE BASE OF THIS IMPRESSIVE INVERSION WILL BE AT ABOUT 600FT...WHICH IS THE LEVEL AT WHICH THE STRATUS DECK WILL BE FOUND. MODELS SHOWING THAT THE WARM AIR RIDING OVER THE WEDGE LEADS TO SOME ISENTROPIC UPGLIDE AND POSSIBLY SOME LIGHT RAINFALL BUT MOST OF BOTH SHOULD REMAIN TO OUR NORTH. THE WEDGE BREAKS DOWN SURPRISINGLY QUICKLY LATE SUNDAY NIGHT INTO MONDAY AND THE WARM AIR ALOFT MENTIONED EARLIER WILL MIX TO THE SURFACE AND BRING A MUCH WARMER AFTERNOON. MODELS HOLDING ON TO RAIN CHANCES...WHICH SEEMS PLAUSIBLE ENOUGH MONDAY MORNING AS WARM FRONT LIFTS THROUGH. MONDAY NIGHT ALSO BRINGS SOME CHANCE FOR RAIN AS THE NEXT COLD FRONT APPROACHES SLOWLY...BEING WELL ALIGNED WITH THE FLOW ALOFT. IN BETWEEN MONDAY AFTERNOON SHOULD BRING A RELATIVE MINIMUM IN RAIN CHANCES. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...COLD FRONT WILL BE IN THE AREA AT THE START OF THE PERIOD...THOUGH THE TIMING OF ITS PASSAGE REMAINS IN QUESTION. ECMWF/CANADIAN HAVE A FAST SOLUTION WITH THE GFS ON THE SLOW SIDE AND NAM IN BETWEEN. THE MID LEVEL PATTERN...BROAD TROUGHING WITH THE TROUGH AXIS TO THE WEST...MEANS FLOW WILL BE ALIGNED ALONG THE BOUNDARY WHICH WOULD SUPPORT SLOWER BOUNDARY MOVEMENT. AT THIS POINT WILL TREND TO THE SLOWER SOLUTION BUT NOT DRASTICALLY...MORE OR LESS IN LINE WITH THE NAM. MID LEVEL PATTERN STARTS TO BECOME MORE PROGRESSIVE DURING THE MIDDLE OF NEXT WEEK PUSHING THE BOUNDARY FARTHER OFF THE COAST AND MOVING ARCTIC HIGH IN FROM THE WEST. THE BRUNT OF THE COLD ADVECTION REMAINS NORTH OF THE AREA BUT TEMPERATURES STILL DROP 5-10 DEGREES BELOW CLIMO BEHIND THE FRONT. SURFACE HIGH SHIFTS OFF THE COAST FRI WITH WEAK COASTAL TROUGH DEVELOPING LATER IN THE DAY AND BECOMING MORE DEFINED SAT. AS IS USUALLY THE CASE WITH A COASTAL TROUGH THERE WILL BE THE POTENTIAL FOR DEVELOPMENT OF WEAK SURFACE WAVE ALONG IT AS THE PERIOD ENDS. TEMPERATURES RETURN NEAR CLIMO FOR THE END OF THE PERIOD...THOUGH THE INCREASE IN TEMP WILL BE ACCOMPANIED BY AN INCREASE IN POP. && .AVIATION /00Z SUNDAY THROUGH WEDNESDAY/... AS OF 00Z...POST FRONTAL MVFR/IFR CIGS PREVAIL THIS EVENING AS THE COLD FRONT NOW LIES OFFSHORE OF THE CAROLINAS. THE LOWEST CIGS ARE BEING REPORTED AT KILM/KCRE/KMYR...WHERE IFR HAS LINGERED THROUGH THE DAY. CIGS COULD BRIEFLY LIFT ABOVE 1KFT TONIGHT ALONG THE COAST...BUT GUIDANCE AND FCST SOUNDINGS SUPPORT PREVAILING IFR STRATUS WITH THE COLD AIR WEDGE IN PLACE. KFLO/KLBT SHOULD SEE MVFR CIGS TONIGHT LOWER TO IFR AFTER 06Z. RADAR RETURNS INDICATE PERIODS OF -RA/DZ ARE LIKELY TONIGHT AS WELL...REDUCING VSBYS TO MVFR/IFR AT TIMES. NORTHEAST WINDS 10-15 KTS WILL PERSIST THROUGH THE PERIOD... WITH A FEW GUSTS AOB 20 KTS POSSIBLE TONIGHT. MODEL SOUNDINGS DEPICT THE COLD WEDGE LOCKED IN PLACE THROUGH SUNDAY...SO STRATUS WILL LIKELY PLAGUE ALL TAF SITES WITH IFR/LIFR CIGS INTO THE AFTN AND EVENING HOURS. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE EXTENDED PERIOD WITH IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY FRONT. SHOWERS LIKELY TUESDAY WITH ANOTHER COLD FRONT. && .MARINE... NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 630 PM SATURDAY...THE COLD FRONT HAS STALLED NEAR THE SOUTH CAROLINA/GEORGIA BORDER AND SHOULD REMAIN THERE THROUGH THE NIGHT. ARCTIC HIGH PRESSURE OVER MINNESOTA WILL PUSH CHILLY NORTH TO NORTHEAST WINDS ACROSS THE AREA TONIGHT...WITH SUSTAINED WIND SPEEDS 20-25 KNOTS EXPECTED. RECENT GUSTS OUT AT THE FRYING PAN SHOALS BUOY HAVE REACHED 27 KNOTS...WITH 22 KNOTS AT WRIGHTSVILLE BEACH AND 21 KNOTS AT MYRTLE BEACH. SEAS HAVE BUILT TO 6 FEET AT FRYING PAN AND 4 FEET AT THE CAPE FEAR RIVER HARBOR BUOY...WITH ANOTHER 1 FOOT INCREASE POSSIBLE BY MIDNIGHT BEFORE SEA HEIGHTS MAX OUT. DRIZZLE WITH PATCHES OF LIGHT RAIN WILL CONTINUE THROUGH THE NIGHT. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...CHILLY WEDGE OF HIGH PRESSURE OVER THE LANDMASS ON SUNDAY TO PINCH GRADIENT EARLY ON. FLAT WAVE OF LOW PRESSURE OFFSHORE TO EASE THE GRADIENT SOME AS THE DAY WEARS ON. AS WIND AND SEAS RELAX THE SMALL CRAFT ADVISORY/6FT SEAS SHOULD ABATE...POSSIBLY A BIT BEFORE THE CURRENT EXPIRATION TIME OF 17Z. SCEC HEADLINES MAY BE NEEDED BUT PROBABLY ONLY BRIEFLY AS THE MARINE GRADIENT CONTINUES TO WEAKEN EVEN AS IT HOLDS FAST OVER LAND. NOT SO SUNDAY NIGHT INTO MONDAY HOWEVER AS THE SHALLOW WEDGE THEN WEAKENS RATHER QUICKLY. THIS ALLOWS THE FLOW TO TURN AROUND TO S OR SW WHILE SPEEDS REMAIN GENERALLY CAPPED AT 10 TO 15KT. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...PASSAGE OF COLD FRONT LATE TUE WILL CAUSE WINDS TO VEER FROM SOUTHWEST TO WEST-NORTHWEST TUE NIGHT. AHEAD OF THE FRONT GRADIENT WILL PRODUCE WINDS IN THE 15 TO 20 KT RANGE WITH LIMITED GUST POTENTIAL GIVEN COOLER WATER TEMPS. POST FRONT COLD ADVECTION IS SLOW TO DEVELOP SO OFFSHORE FLOW TUE NIGHT WILL INITIALLY BE ON THE WEAK SIDE. AROUND DAYBREAK OR SO NORTHERLY FLOW START TO INCREASE AS THE COLD AIR ARRIVES. SPEEDS WED AND THU WILL BE 15 TO 20 KT. OCCASIONAL COLD SURGES COULD PUSH WINDS OVER 20 KT FOR BRIEF PERIODS OF TIME. SEAS WELL AWAY FROM SHORE WILL FLIRT WITH 6 FT FOR A MAJORITY OF THE PERIOD. SOUTHWEST FLOW AHEAD OF THE FRONT WILL PUSH SEAS TO 3 TO 5 FT WITH POTENTIAL FOR HIGHER SEAS IN PLACES. ONCE THE FRONT PASSES THE ABRUPT WIND SHIFT WILL CREATE A CHAOTIC SEA STATE THOUGH SEAS WILL START TRENDING DOWN. THE DOWNWARD TREND ENDS WED MORNING AS COLDER AIR ARRIVES AND WINDS INCREASE...NOW FROM THE NORTH. SEAS RANGING FROM 2 FT NEAR SHORE TO 6 FT NEAR 20 NM WILL BE POSSIBLE WED AND THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST SUNDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...III AVIATION...BJR
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
658 AM EST FRI DEC 6 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS A COLD FRONT APPROACHES FROM THE WEST TONIGHT AND WILL CROSS THE REGION ON SATURDAY AFTERNOON. A STRONGER COLD FRONT WILL CROSS THE REGION TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 655 AM FRIDAY...TEMPERATURES HAVE REMAINED IN THE MID 60S TO AROUND 70 THIS MORNING GIVEN A SOUTHWEST WINDS AT 7 TO 11 KNOTS. GIVEN THIS WARM START...MAXIMUM TEMPERATURES TODAY SHOULD BE ABLE TO REACH THE UPPER 70S TO LOW 80S WELL INLAND WITH LOW TO MID 70S ALONG THE IMMEDIATE COAST. THINK RECORD LOWS MAY BE THREATENED AT LOCATIONS SUCH AS GREENVILLE AND PERHAPS KINSTON LATER TODAY...DESPITE FAIRLY THICK MID AND HIGH LEVEL CLOUDINESS. LATEST HIGH RESOLUTION WRF AND RAP MODELS KEEP PRECIPITATION TO THE WEST AND NORTH OF THE CWA TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... AS OF 325 AM FRIDAY...COLD FRONT WILL APPROACH THE REGION FROM THE WEST LATER TODAY. BEST LOW-LEVEL MOISTURE TRANSPORT DOES NOT ARRIVE IN OUR NORTHERN COUNTIES UNTIL AFTER MIDNIGHT AND WILL SLOWLY RAMP POPS UP WITH CHANCE THRU THE LATE EVENING TO LIKELY OVER NORTHERN COUNTIES BY LATE TONIGHT. QPF TOTALS THROUGH TONIGHT DO NOT LOOK TO BE PARTICULARLY HEAVY...GENERALLY AT ONE-TENTH OF AN INCH OR LESS. TEMPERATURES WILL VERY FROM THE MID TO UPPER 50S ALONG THE FRONT OVER THE NORTHERN COUNTIES...TO THE MILD LOW AND MID 60S AHEAD OF THE FRONT OVER THE SOUTHERN TWO-THIRDS OF THE COUNTY WARNING AREA. && .LONG TERM /SATURDAY THROUGH THURSDAY/... AS OF 330 AM FRI...MODELS CONTINUE IN GOOD AGREEMENT ON PUSHING A SURFACE COLD FRONT THROUGH EASTERN NC SAT MORNING WITH TEMPS WARMEST IN THE MORNING AND SLOWLY FALLING THROUGHOUT THE DAY DUE TO CLOUDS AND PRECIP OVERSPREADING THE REGION FROM NW TO SE. THERE WILL BE A LARGE GRADIENT BETWEEN HEIGHTS/THICKNESSES FROM THE COASTAL PLAIN COUNTIES TO THE COAST...WITH TEMPS FALLING INTO THE 50S BEHIND THE FRONT. FRONTAL BOUNDARY WILL BE AN ANAFRONT WITH CLOUD/PRECIP BEHIND THE FRONT. THE UPPER TROUGH WILL REMAIN CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT REMAINS CENTERED OVER FLORIDA...PLACING EASTERN NC IN SW FLOW ALOFT THROUGH EARLY IN THE WEEK. A STRONG FRONTAL INVERSION WILL BE PRESENT SAT THROUGH SUN AS 850MB WINDS REMAIN SW WITH NLY SURFACE WINDS. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS THROUGH EARLY SUN MORNING. COOLER TEMPS EXPECTED ON SUNDAY DUE TO CLOUDS/PRECIP WITH HIGHS IN THE 40S INLAND TO 50S ALONG THE COAST. LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED BACK INTO THE 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES BUILD 1385-1390 METERS RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL INSOLATION SO HELD TEMPS IN THE LOW 70S INLAND TO UPPER 60S OBX...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST. ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING BRINGING MORE UNSETTLED WEATHER WITH RAIN AGAIN MOSTLY POST- FRONTAL AND CONTINUING INTO TUES EVENING BEFORE STRONG HIGH PRESSURE OVER THE CENTRAL CONUS SHIFTS EAST OVER THE MID-ATLANTIC REGION. WED/THURS WILL BE DRY AND MUCH COOLER WITH TEMPS STRUGGLING TO BUILD INTO THE MID 40S DUE TO STRONG COLD AIR ADVECTION IN NLY FLOW. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... SHORT TERM /TODAY AND TONIGHT/... AS OF 655 AM FRIDAY...WITH A LIGHT SOUTHWEST WINDS AT 7 TO 11 KNOTS CONTINUING OVERNIGHT...FOG HAS NOT DEVELOPED AT THE TAF SITES THIS MORNING. EXTENSIVE MID AND HIGH LEVEL CLOUDINESS WILL PERSIST THROUGH THE DAY. WINDS GUSTING BETWEEN 15 AND 20 KNOTS ARE POSSIBLE LATER IN THE DAY IN ADVANCE OF AN APPROACHING COLD FRONT. NUMERICAL GUIDANCE AGAIN INDICATES PATCHY DENSE FOG LATE TONIGHT...BUT WITH CONTINUE LIGHT TO MODERATE SW WINDS...AGAIN WILL BE LIMITED IN SCOPE AND WILL FORECAST JUST MVFR STRATUS AT THIS TIME. LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 335 AM FRI...A COLD FRONT WILL APPROACH FROM THE NW FRI NIGHT...MOVING THROUGH THE TERMINALS SAT MORNING. MODEL SOUNDINGS INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS EXPECTED TO DEVELOP LATE FRI NIGHT AND CONTINUE THROUGH MUCH OF SUNDAY...WITH WIDESPREAD RAIN ALSO DEVELOPING THIS WEEKEND. N/NE WIND GUSTS 15-20KT EXPECTED BEHIND THE FRONT SAT AFTERNOON. A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER MON WITH PRECIP CHANCES DIMINISHING AND LOWER CIGS LIFTING N OF THE REGION THOUGH FOG MAY BE A POSSIBILITY AT NIGHT. ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT WITH CONDITIONS IMPROVING TO VFR. && .MARINE... SHORT TERM /TODAY AND TONIGHT/... AS OF 655 AM FRIDAY...BASED ON CURRENT OBSERVATIONAL TRENDS...HAVE UPPED WINDS TO 15 T0 20 KNOTS ON THE COASTAL WATERS NORTH OF CAPE LOOKOUT. HAVE ALSO ADDED THE PAMLICO SOUND TO THE SMALL CRAFT ADVISORY WHICH WILL BEGIN AT 03Z TONIGHT WITH GUSTY SW WINDS EXPECTED. SEAS REMAIN IN THE 2 TO 3 FOOT RANGE...BUT PER LOCAL NWPS/SWAN MODEL AND WAVEWATCH GUIDANCE...SEAS WILL BUILD TO AS HIGH AS 6 FEET BY LATE THIS EVENING AND TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 345 AM FRI...SCA CONDITIONS WILL PERSIST OVER THE WATERS THROUGH THE WEEKEND AS SW WINDS INCREASE TO 20 KT OR HIGHER WITH SEAS REACHING 6 FT FOR THE OUTER CENTRAL/SOUTHERN WATERS. FRONT WILL PASS THROUGH THE WATERS BY MIDDAY SAT WITH NORTHERLY CAA SURGE INCREASING WINDS TO 20 KNOTS WITH SEAS 5-7 FT THROUGH SUN MORNING. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS LATE SUN NIGHT. WINDS AND SEAS BRIEFLY SUBSIDE BELOW SCA CRITERIA MON MORNING WITH SW WINDS 10-15 KT AND SEAS 3-5 FT...THEN INCREASE TO 15-20 KT AND SEAS 4-7 FT AS THE GRADIENT TIGHTENS BETWEEN SURFACE RIDGE OFF THE SOUTHEASTERN COAST AND A COLD FRONT APPROACHING FROM THE NW. SCA CONDITIONS EXPECTED MON AFTERNOON LASTING THROUGH AT LEAST TUES. WAVEWATCH III AND LOCAL SWAN/NWPS IN GOOD AGREEMENT THROUGH THE LONG TERM. && .CLIMATE... RECORD HIGH (79) WAS SET IN NEW BERN ON THURSDAY AND MORE RECORD WARMTH LIKELY ON FRIDAY. BELOW IS A SUMMARY OF THE CLIMATOLOGICAL RECORD HIGH TEMPERATURES FOR FRIDAY...DECEMBER 6TH: RECORD HIGH FOR DEC 6: NEW BERN 81 (1998) GREENVILLE 80 (1998) KINSTON 81 (1982) NEWPORT 77 (1998) BAYBORO 82 (1998) MOREHEAD CITY 74 (2011) WILLIAMSTON 76 (1998) CAPE HATTERAS 77 (1982) OCRACOKE 73 (1975) MANTEO 78 (1998) && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST SUNDAY FOR AMZ135. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST SUNDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST SUNDAY FOR AMZ156-158. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...DAG AVIATION...CTC/DAG MARINE...CTC/DAG CLIMATE...CTC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
347 AM EST FRI DEC 6 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS A COLD FRONT APPROACHES FROM THE WEST TONIGHT AND WILL CROSS THE REGION ON SATURDAY AFTERNOON. A STRONGER COLD FRONT WILL CROSS THE REGION TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 320 AM FRIDAY...WITH A S/SSW WIND OF ABOUT 7 OR 8 KNOTS LINGERING...TEMPERATURES ARE VERY MILD FOR BOTH THIS TIME OF YEAR AND THIS TIME OF NIGHT...HOVERING IN THE MID TO UPPER 60S AREA- WIDE. GIVEN THIS WARM START...MAXIMUM TEMPERATURES TODAY SHOULD BE ABLE TO REACH THE UPPER 70S TO LOW 80S WELL INLAND WITH LOW TO MID 70S ALONG THE IMMEDIATE COAST. THINK RECORD LOWS MAY BE THREATENED AT LOCATIONS SUCH AS GREENVILLE AND PERHAPS KINSTON LATER TODAY...DESPITE FAIRLY THICK MID AND HIGH LEVEL CLOUDINESS. LATEST HIGH RESOLUTION WRF AND RAP MODELS KEEP PRECIPITATION TO THE WEST AND NORTH OF THE CWA TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... AS OF 325 AM FRIDAY...COLD FRONT WILL APPROACH THE REGION FROM THE WEST LATER TODAY. BEST LOW-LEVEL MOISTURE TRANSPORT DOES NOT ARRIVE IN OUR NORTHERN COUNTIES UNTIL AFTER MIDNIGHT AND WILL SLOWLY RAMP POPS UP WITH CHANCE THRU THE LATE EVENING TO LIKELY OVER NORTHERN COUNTIES BY LATE TONIGHT. QPF TOTALS THROUGH TONIGHT DO NOT LOOK TO BE PARTICULARLY HEAVY...GENERALLY AT ONE-TENTH OF AN INCH OR LESS. TEMPERATURES WILL VERY FROM THE MID TO UPPER 50S ALONG THE FRONT OVER THE NORTHERN COUNTIES...TO THE MILD LOW AND MID 60S AHEAD OF THE FRONT OVER THE SOUTHERN TWO-THIRDS OF THE COUNTY WARNING AREA. && .LONG TERM /SATURDAY THROUGH THURSDAY/... AS OF 330 AM FRI...MODELS CONTINUE IN GOOD AGREEMENT ON PUSHING A SURFACE COLD FRONT THROUGH EASTERN NC SAT MORNING WITH TEMPS WARMEST IN THE MORNING AND SLOWLY FALLING THROUGHOUT THE DAY DUE TO CLOUDS AND PRECIP OVERSPREADING THE REGION FROM NW TO SE. THERE WILL BE A LARGE GRADIENT BETWEEN HEIGHTS/THICKNESSES FROM THE COASTAL PLAIN COUNTIES TO THE COAST...WITH TEMPS FALLING INTO THE 50S BEHIND THE FRONT. FRONTAL BOUNDARY WILL BE AN ANAFRONT WITH CLOUD/PRECIP BEHIND THE FRONT. THE UPPER TROUGH WILL REMAIN CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT REMAINS CENTERED OVER FLORIDA...PLACING EASTERN NC IN SW FLOW ALOFT THROUGH EARLY IN THE WEEK. A STRONG FRONTAL INVERSION WILL BE PRESENT SAT THROUGH SUN AS 850MB WINDS REMAIN SW WITH NLY SURFACE WINDS. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS THROUGH EARLY SUN MORNING. COOLER TEMPS EXPECTED ON SUNDAY DUE TO CLOUDS/PRECIP WITH HIGHS IN THE 40S INLAND TO 50S ALONG THE COAST. LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED BACK INTO THE 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES BUILD 1385-1390 METERS RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL INSOLATION SO HELD TEMPS IN THE LOW 70S INLAND TO UPPER 60S OBX...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST. ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING BRINGING MORE UNSETTLED WEATHER WITH RAIN AGAIN MOSTLY POST- FRONTAL AND CONTINUING INTO TUES EVENING BEFORE STRONG HIGH PRESSURE OVER THE CENTRAL CONUS SHIFTS EAST OVER THE MID-ATLANTIC REGION. WED/THURS WILL BE DRY AND MUCH COOLER WITH TEMPS STRUGGLING TO BUILD INTO THE MID 40S DUE TO STRONG COLD AIR ADVECTION IN NLY FLOW. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... SHORT TERM /TODAY AND TONIGHT/... AS OF 325 AM FRIDAY...GIVEN A S/SW WIND IN THE 6 TO 8 KNOT RANGE...DO NOT EXPECT MUCH IN THE WAY OF DENSE FOG AT THE TAF SITES. EXPECT VFR WITH INCREASING WSW WINDS THROUGH THE DAY FRIDAY. WIND GUSTS 20-25 KT LIKELY FROM LATE MORNING THRU MID AFTERNOON FRIDAY. GUIDANCE AGAIN INDICATES PATCHY DENSE FOG LATE FRIDAY NIGHT...BUT WITH SOME LIGHT SW WINDS...AGAIN MAY BE LIMITED IN SCOPE. LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 335 AM FRI...A COLD FRONT WILL APPROACH FROM THE NW FRI NIGHT...MOVING THROUGH THE TERMINALS SAT MORNING. MODEL SOUNDINGS INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS EXPECTED TO DEVELOP LATE FRI NIGHT AND CONTINUE THROUGH MUCH OF SUNDAY...WITH WIDESPREAD RAIN ALSO DEVELOPING THIS WEEKEND. N/NE WIND GUSTS 15-20KT EXPECTED BEHIND THE FRONT SAT AFTERNOON. A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER MON WITH PRECIP CHANCES DIMINISHING AND LOWER CIGS LIFTING N OF THE REGION THOUGH FOG MAY BE A POSSIBILITY AT NIGHT. ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT WITH CONDITIONS IMPROVING TO VFR. && .MARINE... SHORT TERM /TODAY AND TONIGHT/... AS OF 325 AM FRIDAY...THE TIGHTENING PRESSURE GRAD AHEAD OF AN APPROACHING COLD FRONT WILL RESULT IN INCREASING S-SW WINDS TO 15-20 KTS BY LATER THIS AFTERNOON...INCREASING TO 20 TO 25 KT LATER TONIGHT. AS A RESULT...HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE COASTAL WATERS BEGINNING AT 03Z SATURDAY. SEAS ARE CURRENTLY IN THE 2 TO 3 FOOT RANGE...BUT PER LOCAL NWPS/SWAN MODEL AND WAVEWATCH GUIDANCE...SEAS WILL BUILD TO AS HIGH AS 6 FEET BY LATE THIS EVENING AND TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 345 AM FRI...SCA CONDITIONS WILL PERSIST OVER THE WATERS THROUGH THE WEEKEND AS SW WINDS INCREASE TO 20 KT OR HIGHER WITH SEAS REACHING 6 FT FOR THE OUTER CENTRAL/SOUTHERN WATERS. FRONT WILL PASS THROUGH THE WATERS BY MIDDAY SAT WITH NORTHERLY CAA SURGE INCREASING WINDS TO 20 KNOTS WITH SEAS 5-7 FT THROUGH SUN MORNING. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS LATE SUN NIGHT. WINDS AND SEAS BRIEFLY SUBSIDE BELOW SCA CRITERIA MON MORNING WITH SW WINDS 10-15 KT AND SEAS 3-5 FT...THEN INCREASE TO 15-20 KT AND SEAS 4-7 FT AS THE GRADIENT TIGHTENS BETWEEN SURFACE RIDGE OFF THE SOUTHEASTERN COAST AND A COLD FRONT APPROACHING FROM THE NW. SCA CONDITIONS EXPECTED MON AFTERNOON LASTING THROUGH AT LEAST TUES. WAVEWATCH III AND LOCAL SWAN/NWPS IN GOOD AGREEMENT THROUGH THE LONG TERM. && .CLIMATE... RECORD HIGH (79) WAS SET IN NEW BERN ON THURSDAY AND MORE RECORD WARMTH LIKELY ON FRIDAY. BELOW IS A SUMMARY OF THE CLIMATOLOGICAL RECORD HIGH TEMPERATURES FOR FRIDAY...DECEMBER 6TH: RECORD HIGH FOR DEC 6: NEW BERN 81 (1998) GREENVILLE 80 (1998) KINSTON 81 (1982) NEWPORT 77 (1998) BAYBORO 82 (1998) MOREHEAD CITY 74 (2011) WILLIAMSTON 76 (1998) CAPE HATTERAS 77 (1982) OCRACOKE 73 (1975) MANTEO 78 (1998) && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST SUNDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST SUNDAY FOR AMZ156-158. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...DAG AVIATION...CTC/DAG MARINE...CTC/DAG CLIMATE...CTC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
409 PM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT INTO EARLY SATURDAY MORNING...BRINGING MIXED AND FROZEN PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY INTO SATURDAY NIGHT. CONFIDENCE CONTINUES TO INCREASE FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN EARLIER FORECASTS. THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW IS LIKELY BEFORE 9 PM. IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT MIDNIGHT. MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY. SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS EVENING... && .SHORT TERM /9 PM THIS EVENING THROUGH SATURDAY NIGHT/... KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE... BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND. WE WENT WITH THE HIGHER PROBABILITY FORECAST. RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING. SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE. LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND NORTHWESTERN MOUNTAINS SATURDAY. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AFTER A BRIEF RESPITE FROM THE ACTIVE EARLY-SEASON WINTER WEATHER PATTERN...THE COMBINATION OF LOW-LEVEL COLD AIR ASSOCIATED WITH A RETREATING ARCTIC SFC HIGH...A STRONG UPPER RIDGE OFF THE SOUTHEAST COAST...AND A PERSISTENT MOIST SOUTHWESTERLY UPPER FLOW WITH EMBEDDED WEAK SYSTEMS OPERATING ON AN INTENSE/TIGHT FRONTAL- BAROCLINIC ZONE /RATHER THAN ONE CONCENTRATED IMPULSE/ WILL BRING ANOTHER ROUND OF MIXED/WINTRY PRECIPITATION TO THE REGION SUNDAY- MONDAY. THE FRONTAL ZONE AND AND STRONG UPPER JET WILL SHIFT OFF THE COAST INTO THE MIDDLE OF THE WEEK...ALLOWING A VERY COLD AIRMASS TO SPREAD INTO THE REGION FOR LATE IN THE PERIOD. ALL SIGNS CONTINUE TO POINT TOWARD A CLASSIC OVERRUNNING MIXED WINTRY PRECIP EVENT FOR SUNDAY-MONDAY...ALTHOUGH THERE ARE SOME MODEL DIFFS WITH REGARDS TO THE TIMING AND NRN EXTENT OF THE PRECIP SHIELD. A 150 KT UPPER JET WILL SHIFT NORTHWARD AS WEAK IMPULSES EJECT NORTHEASTWARD OUT OF THE DEEP WESTERN TROUGH...WITH PRECIPITATION EXPANDING NORTHWARD ALONG AN INVERTED SFC TROUGH AXIS ACROSS THE SOUTHEAST/TENNESSEE VALLEY INTO THE MIDDLE ATLANTIC STATES. A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND THE FAST SWLY FLOW ALOFT AND OVERRUN A SHALLOW LAYER OF LLVL SUB-FREEZING AIR DRAINING SWD ALONG THE ERN SLOPES OF THE APPLCHNS. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN /SN-PL-FZRA/ AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 06/12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING GIVEN POTENTIAL FOR ICE ACCUM >0.25 INCH. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... DETERIORATING FLYING CONDS ARE EXPECTED ACROSS CENTRAL PA THIS AFTN/EVE...AS ANOTHER ROUND OF PRECIPITATION PUSHES BACK INTO THE AREA. NRN AND WRN TAF SITES WILL LIKELY SEE A WINTRY MIX CHANGING TO SNOW THIS EVENING...WITH RAIN CONTINUING FARTHER TO THE SOUTHEAST /MDT AND LNS/. THE PRECIP SHOULD GRADUALLY TAPER OFF OVERNIGHT...WITH EVEN MDT AND LNS POSSIBLY SEEING A BRIEF CHANGEOVER TO SNOW BEFORE THE PRECIP ENDS. IMPROVING CONDS EXPECTED FOR SATURDAY...AS THE SYSTEM PULLS EAST OF THE REGION. NORTHWEST FLOW DEVELOPS...AND WE SHOULD SEE A RETURN TO VFR CONDS. UPSLOPING NW FLOW COULD DELAY THE IMPROVEMENT FOR THE WRN TAF SITES /JST AND BFD/...BUT EVEN THEY SHOULD IMPROVE AS THE DAY PROGRESSES. THINGS REMAIN QUIET SAT NIGHT INTO EARLY SUNDAY...BEFORE THE NEXT SYSTEM BRINGS LOWERING CIGS AND SNOW DEVELOPING SUNDAY AFTN. THE SNOW IS EXPECTED TO CHANGE OVER TO A WINTRY MIX OR RAIN SUNDAY NIGHT...BEFORE GRADUALLY TAPERING OFF MONDAY. OUTLOOK... SAT...BECOMING VFR CENTRAL/EASTERN AREAS...WITH LOWER CIGS POSSIBLY LINGERING ACROSS THE NORTH AND WEST. SUN...VFR WILL GIVE WAY TO MVFR/IFR AS THE NEXT ROUND OF WINTRY PRECIP ARRIVES. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. TUE-WED...WEST TO NORTHWEST FLOW DEVELOPING. COLD WITH SCT -SHSN NORTH AND WEST. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 AM EST SATURDAY FOR PAZ019- 024>028-033>035-042-045-046-049>053. WINTER STORM WARNING UNTIL 5 AM EST SATURDAY FOR PAZ004>006- 010>012-017-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
119 PM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN EARLIER FORECASTS. THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW IS LIKELY BEFORE 9 PM. IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT MIDNIGHT. MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY. SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING. KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS EVENING... && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/... KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE... BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND. WE WENT WITH THE HIGHER PROBABILITY FORECAST. RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING. SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE. LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND NORTHWESTERN MOUNTAINS SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS.... PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... DETERIORATING FLYING CONDS ARE EXPECTED ACROSS CENTRAL PA THIS AFTN/EVE...AS ANOTHER ROUND OF PRECIPITATION PUSHES BACK INTO THE AREA. NRN AND WRN TAF SITES WILL LIKELY SEE A WINTRY MIX CHANGING TO SNOW THIS EVENING...WITH RAIN CONTINUING FARTHER TO THE SOUTHEAST /MDT AND LNS/. THE PRECIP SHOULD GRADUALLY TAPER OFF OVERNIGHT...WITH EVEN MDT AND LNS POSSIBLY SEEING A BRIEF CHANGEOVER TO SNOW BEFORE THE PRECIP ENDS. IMPROVING CONDS EXPECTED FOR SATURDAY...AS THE SYSTEM PULLS EAST OF THE REGION. NORTHWEST FLOW DEVELOPS...AND WE SHOULD SEE A RETURN TO VFR CONDS. UPSLOPING NW FLOW COULD DELAY THE IMPROVEMENT FOR THE WRN TAF SITES /JST AND BFD/...BUT EVEN THEY SHOULD IMPROVE AS THE DAY PROGRESSES. THINGS REMAIN QUIET SAT NIGHT INTO EARLY SUNDAY...BEFORE THE NEXT SYSTEM BRINGS LOWERING CIGS AND SNOW DEVELOPING SUNDAY AFTN. THE SNOW IS EXPCETED TO CHANGE OVER TO A WINTRY MIX OR RAIN SUNDAY NIGHT...BEFORE GRADUALLY TAPERING OFF MONDAY. OUTLOOK... SAT...BECOMING VFR CENTRAL/EASTERN AREAS...WITH LOWER CIGS POSSIBLY LINGERING ACROSS THE NORTH AND WEST. SUN...VFR WILL GIVE WAY TO MVFR/IFR AS THE NEXT ROUND OF WINTRY PRECIP ARRIVES. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. TUE-WED...WEST TO NORTHWEST FLOW DEVELOPING. COLD WITH SCT -SNSH NORTH AND WEST. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053. WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1239 PM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN EARLIER FORECASTS. THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW IS LIKELY BEFORE 9 PM. IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT MIDNIGHT. MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY. SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING. KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS EVENING... && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/... ...KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE... BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND. WE WENT WITH THE HIGHER PROBABILITY FORECAST. RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING. SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE. LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND NORTHWESTERN MOUNTAINS SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS.... PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... A SHALLOW FRONTAL BOUNDARY BROUGHT AN END TO MOST OF THE PRECIPITATION ACROSS THE REGION THIS MORNING. MOST VFR AND MVFR CONDITIONS FOR THE NEXT FEW HOURS. SNOW WILL MOVE INTO NORTHWESTERN AREAS THIS AFTERNOON AND LOWER CEILINGS AND HEIGHTS. RAIN AND SNOW WILL MOVE INTO CENTRAL AREAS IN THE 19 TO 22Z TIME-FRAME LOWERING CEILINGS AND HEIGHTS IN THAT REGION. RAIN WILL MOVE INTO SOUTHERN REGIONS. SHOULD BE MOSTLY IFR WITH AREAS OF LIFR IN SNOW AND RAIN. THERE WILL BE A RAPID CHANGE OVER TO ALL SNOW IN CENTRAL AREAS FROM ABOUT KAOO-KUNV-KIPT THIS EVENING. THE PRECIPITATION SHOULD END RAPIDLY AFTER MIDNIGHT WITH A RETURN TO MOSTLY VFR ON SATURDAY WITH SOME AREAS OF SNOW SHOWERS IN THE WESTERN MOUNTAINS. OUTLOOK... FRI...VFR/MVFR SOME RAIN SE. AFTERNOON-EVEN...IFR IN SNOW/WINTRY MIX AND RAIN. SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN AREAS. SUN...VFR WILL GIVE WAY TO IFR AS A WINTER STORM RAPIDLY SWEEPS INTO THE REGION SUNDAY INTO SUNDAY NIGHT. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053. WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1115 AM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... AN ENHANCED AREA OF ENHANCED CLOUDS AND LIGHT RAIN WILL MOVE ACROSS SOUTHEASTERN PA. A SHALLOW FRONTAL BOUNDARY OVER THE REGION IS SLOWLY PUSHING COLD AIR IN FROM NORTHWEST TO SOUTH EAST. TEMPERATURES ARE BELOW FREEZING IN NW PA AND IN THE 40S IN THE SOUTHEAST. THE 850 MB ZERO ISOTHERM IS IN NW PA. FRONTAL ZONE AT 850 AND A WAVE TO THE WEST WILL PRODUCE SNOW...HEAVY SNOW...SOME ICE...AND RAIN OVER THE STATE IN THE NEXT 18 HOURS. THE MAIN PLAYER IS REALLY A LARGE ANTICYCLONE TO THE WEST AND COLD AIR. THE "STORM" IS REALLY JUST A STRONG FRONTAL ZONE. THE SREF AND GEFS SUGGEST SNOW WILL MOVE INTO NORTHWESTERN PA THIS AFTERNOON AND LATER THIS AFTERNOON RAIN WILL MOVE INTO CENTRAL PA. A SNOW-BAND IS EVOLVING OVER OHIO. THE RAP AND 4KM NAM SUGGEST THE HEAVIEST SNOW COULD BE A BIT MORE SOUTH THAN THE 16KM SREF AND 55KM GEFS. THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AND TO ABOUT MIDNIGHT IN NORTHWESTERN PA. SIGNIFICANT SNOW IS LIKELY BEFORE 9 PM. IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT MIDNIGHT. MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY. SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING. KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS EVENING... && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/... BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND. WE WENT WITH THE HIGHER PROBABILITY FORECAST. RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING. THE MODELS SUGGEST THE PRECIPITATION IS WELL TO OUR EAST A FEW HOURS EITHER SIDE OF ABOUT 7 AM. SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE. LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND NORTHWESTERN MOUNTAINS SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS.... PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... A SHALLOW FRONTAL BOUNDARY BROUGHT AN END TO MOST OF THE PRECIPITATION ACROSS THE REGION THIS MORNING. MOST VFR AND MVFR CONDITIONS FOR THE NEXT FEW HOURS. SNOW WILL MOVE INTO NORTHWESTERN AREAS THIS AFTERNOON AND LOWER CEILINGS AND HEIGHTS. RAIN AND SNOW WILL MOVE INTO CENTRAL AREAS IN THE 19 TO 22Z TIME-FRAME LOWERING CEILINGS AND HEIGHTS IN THAT REGION. RAIN WILL MOVE INTO SOUTHERN REGIONS. SHOULD BE MOSTLY IFR WITH AREAS OF LIFR IN SNOW AND RAIN. THERE WILL BE A RAPID CHANGE OVER TO ALL SNOW IN CENTRAL AREAS FROM ABOUT KAOO-KUNV-KIPT THIS EVENING. THE PRECIPITATION SHOULD END RAPIDLY AFTER MIDNIGHT WITH A RETURN TO MOSTLY VFR ON SATURDAY WITH SOME AREAS OF SNOW SHOWERS IN THE WESTERN MOUNTAINS. OUTLOOK... FRI...VFR/MVFR SOME RAIN SE. AFTERNOON-EVEN...IFR IN SNOW/WINTRY MIX AND RAIN. SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN AREAS. SUN...VFR WILL GIVE WAY TO IFR AS A WINTER STORM RAPIDLY SWEEPS INTO THE REGION SUNDAY INTO SUNDAY NIGHT. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053. WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1056 AM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... AN ENHANCED AREA OF ENHANCED CLOUDS AND LIGHT RAIN WILL MOVE ACROSS SOUTHEASTERN PA. A SHALLOW FRONTAL BOUNDARY OVER THE REGION IS SLOWLY PUSHING COLD AIR IN FROM NORTHWEST TO SOUTH EAST. TEMPERATURES ARE BELOW FREEZING IN NW PA AND IN THE 40S IN THE SOUTHEAST. THE 850 MB ZERO ISOTHERM IS IN NW PA. FRONTAL ZONE AT 850 AND A WAVE TO THE WEST WILL PRODUCE SNOW...HEAVY SNOW...SOME ICE...AND RAIN OVER THE STATE IN THE NEXT 18 HOURS. THE MAIN PLAYER IS REALLY A LARGE ANTICYCLONE TO THE WEST AND COLD AIR. THE "STORM" IS REALLY JUST A STRONG FRONTAL ZONE. THE SREF AND GEFS SUGGEST SNOW WILL MOVE INTO NORTHWESTERN PA THIS AFTERNOON AND LATER THIS AFTERNOON RAIN WILL MOVE INTO CENTRAL PA. A SNOW-BAND IS EVOLVING OVER OHIO. THE RAP AND 4KM NAM SUGGEST THE HEAVIEST SNOW COULD BE A BIT MORE SOUTH THAN THE 16KM SREF AND 55KM GEFS. THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AND TO ABOUT MIDNIGHT IN NORTHWESTERN PA. SIGNIFICANT SNOW IS LIKELY BEFORE 9 PM. IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT MIDNIGHT. MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY. SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING. ...KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS EVENING... && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/... BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND. WE WENT WITH THE HIGHER PROBABILITY FORECAST. RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING. THE MODELS SUGGEST THE PRECIPITATION IS WELL TO OUR EAST A FEW HOURS EITHER SIDE OF ABOUT 7 AM. SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE. LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND NORTHWESTERN MOUNTAINS SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... ...THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS.... ...PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... SHOWERS CONTINUE TO STREAM ACROSS SOUTHERN AND CENTRAL PA WITH LIGHT MIXED PRECIPITATION OVER JST AND BFD. THIS STEADY WAVE OF RAIN MOVING THROUGH CENTRAL PA AND THE LOWER SUSQ WILL CONTINUE THROUGH THE MORNING. CIGS FOR MOST TAF SITES HAVE LIFTED TO MVFR...AND WILL REMAIN AROUND MVFR THROUGH THE MORNING AND EARLY AFTERNOON. JST CURRENTLY HAS LIFR CIGS AND WILL SEE THESE CONTINUE THROUGH THE MORNING AND EARLY AFTERNOON BEFORE SLIGHTLY LIFTING. THESE WILL BE MVFR AND LOWER THROUGH TONIGHT. EXPECT THE MIXED PRECIPITATION TO SWITCH TO RAIN THROUGH THE AFTERNOON HOURS BEFORE SWITCHING TO A WINTRY MIX LATE THIS AFTERNOON AND SWITCHING TO SNOW TONIGHT. EXPECT IFR CIGS AND VSBYS TO CONTINUE TONIGHT INTO EARLY TOMORROW. MOST TAF SITES SHOULD BEGIN TO CLEAR EARLY TOMORROW MORNING. OUTLOOK... FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW. SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN AREAS. SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053. WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
239 AM EST FRI DEC 6 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...JUST WEST OF KUNV AND KAOO AT 0330Z. NEAR TERM MODELS AGREE IN TRACKING COLD FRONT SE ACROSS THE AREA OVERNIGHT. ALTHOUGH RAIN TAPERED OFF A BIT ACROSS CENTRAL PA EARLIER THIS EVENING...REGIONAL RADAR MOSAIC SHOWING ANOTHER BATCH OF RAIN APPROACHING FROM WESTERN PA AT 0330Z. UPSTREAM WATER VAPOR LOOP SHOWS A SHORTWAVE OVR ILLINOIS AT 03Z...WHICH SHOULD LIFT NE ACROSS THE E GRT LKS OVERNIGHT. LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD HELP SUPPORT NEXT BATCH OF PRECIP LATE THIS EVENING THRU ARND 10Z. 02Z RAP FRONTOGENESIS PATTERNS MATCH WELL WITH BAND OF SNOW FALLING FROM CENTRAL INDIANA TO NW OHIO. RAP INDICATES THIS BAND OF ENHANCED FGEN LIFTS ACROSS NW PA BTWN 06Z-09Z AS MDL SOUNDINGS BECOME COLD ENOUGH FOR SNOW. SO...BELIEVE A LIGHT SNOW ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS LATE TONIGHT. FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY. HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING. STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA. BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW. HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE START TIME OF THEIR ADVISORY TO 22Z. DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND MIDNIGHT. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... 1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... ARES OF SHOWERS WILL CONTINUE TO STREAM THROUGH THE REGION OVERNIGHT. THIS STEADY WAVE OF RAIN MOVING THROUGH CENTRAL PA. LIFR WILL CONTINUE OVER THE LOWER SUSQ TERMINALS WHERE FOG IS STILL LOCALLY DENSE. OTHERWISE...MVFR AND LOWER FLIGHT CATEGORIES WILL CONTINUE INTO THIS MORNING AS MORE RAIN...SNOW...AND WINTRY MIX OVERSPREAD THE REGION. OUTLOOK... FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW. SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN AREAS. SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041-042. WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST SATURDAY FOR PAZ024-033. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL LONG TERM...STEINBUGL AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1153 PM EST THU DEC 5 2013 .SYNOPSIS... A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT WEDNESDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...JUST WEST OF KUNV AND KAOO AT 0330Z. NEAR TERM MODELS AGREE IN TRACKING COLD FRONT SE ACROSS THE AREA OVERNIGHT. ALTHOUGH RAIN TAPERED OFF A BIT ACROSS CENTRAL PA EARLIER THIS EVENING...REGIONAL RADAR MOSAIC SHOWING ANOTHER BATCH OF RAIN APPROACHING FROM WESTERN PA AT 0330Z. UPSTREAM WATER VAPOR LOOP SHOWS A SHORTWAVE OVR ILLINOIS AT 03Z...WHICH SHOULD LIFT NE ACROSS THE E GRT LKS OVERNIGHT. LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD HELP SUPPORT NEXT BATCH OF PRECIP LATE THIS EVENING THRU ARND 10Z. 02Z RAP FRONTOGENESIS PATTERNS MATCH WELL WITH BAND OF SNOW FALLING FROM CENTRAL INDIANA TO NW OHIO. RAP INDICATES THIS BAND OF ENHANCED FGEN LIFTS ACROSS NW PA BTWN 06Z-09Z AS MDL SOUNDINGS BECOME COLD ENOUGH FOR SNOW. SO...BELIEVE A LIGHT SNOW ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS LATE TONIGHT. FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY. HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING. STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA. BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW. HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE START TIME OF THEIR ADVISORY TO 22Z. DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND MIDNIGHT. && .LONG TERM /SATURDAY THROUGH THURSDAY/... 1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO MONDAY. 05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS. THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN NEW ENGLAND. DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING ASSUMING MOD-HVY ICING VIA FZRA. IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE INTO SW NY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... NEXT WAVE OF STEADY RAIN MOVING INTO CENTRAL PA ATTM. THIS WILL LEAD TO SOME IMPROVEMENT OF LIFR VSBYS...AT LEAST FOR AT TIME WHILE IT IS RAINING OVER THE NEXT SEVERAL HOURS. UNTIL STEADIER RAIN REACHES EAST...LIFR WILL CONTINUE OVER THE LOWER SUSQ TERMINALS WHERE FOG IS STILL LOCALLY DENSE. OTHERWISE...MVFR AND LOWER FLIGHT CATEGORIES WILL CONTINUE INTO FRIDAY AS MORE RAIN...SNOW...AND WINTRY MIX OVERSPREAD THE REGION. OUTLOOK... FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW. SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN AREAS. SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT. MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 1 PM FRIDAY TO 5 AM EST SATURDAY FOR PAZ004>006-010>012-017-018-037-041-042. WINTER WEATHER ADVISORY FROM 5 PM FRIDAY TO 5 AM EST SATURDAY FOR PAZ024-033. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL LONG TERM...STEINBUGL AVIATION...GARTNER/COLBERT
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1140 PM CST THU DEC 5 2013 .DISCUSSION... SEE THE 06Z AVIATION DISCUSSION BELOW. 40 && .AVIATION... MAIN FORECAST ITEMS OF CONCERN WILL BE CEILINGS AND WINDS. MODEL FORECAST SOUNDINGS KEEP IFR THROUGH FRIDAY MORNING...WITH THE CEILINGS LIFTING TO MVFR DURING THE AFTERNOON PERIOD. THE SOUNDINGS DO NOT SUPPORT MUCH IN THE WAY OF CONVECTION...AND FELT LIGHT DRIZZLE WILL MOST LIKELY OCCUR. WINDS ALONG THE COAST WILL LIKELY GUST TO ABOVE 25 KNOTS OVERNIGHT TONIGHT AND SHOULD PERSIST AT KGLS THROUGH FRIDAY AFTERNOON. THE GUIDANCE SUGGESTS MVFR CONDITIONS LIFTING FRIDAY EVENING FROM ABOUT HOUSTON SOUTH TO THE COAST. HOWEVER...THE MODEL FORECAST SOUNDINGS INDICATE THAT MVFR CONDITIONS WILL LIKELY LOWER TOWARD IFR DURING THE LATE EVENING. WITH COLD AIR ADVECTION COUPLED WITH THE STRENGTHENING SURFACE PRESSURE GRADIENT...THE WINDS ALONG THE IMMEDIATE COAST WILL LIKELY STRENGTHEN FRIDAY EVENING TO GUST TO AROUND 30 KNOTS AT KGLS BEGINNING AROUND 00Z. OVER THE INLAND SITES...FELT THAT THE GUIDANCE WAS ON TRACK IN DIMINISHING THE WIND GUSTS AROUND SUNSET. 40 && .PREV DISCUSSION... /ISSUED 928 PM CST THU DEC 5 2013/ UPDATE... UPDATE TO ISSUE A WIND ADVISORY FOR THE COASTAL COUNTIES. DISCUSSION... WIND SPEEDS HAVE INCREASED AND WIND ADVISORY CRITERIA HAS BEEN MET ALONG THE COAST. A WIND ADVISORY WILL BE IN EFFECT THROUGH 4 AM FOR THE COASTAL COUNTIES. CONCERN IS GROWING FOR WINTER PRECIP OVER THE NW ZONES TONIGHT. TEMPS ARE GETTING DANGEROUSLY CLOSE TO FREEZING. JACKSONVILLE AND PALASTINE ARE BOTH REPORTING SLEET. SFC DEW PTS CONTINUE TO DROP AND AM CONCERNED ABOUT EVAPORATIVE COOLING LOWERING SFC TEMPS TO NEAR OR JUST BELOW FREEZING. NAM 12 FCST SOUNDINGS SHOW SFC TEMPS FALLING TO 32 DEGREES AT 09Z AND 31 DEGREES 12Z-18Z. THE NAM12 SFC DEW PT FIELD IS WARMER SO THERE ARE CONFLICTING SIGNALS BETWEEN SFC PARAMETERS AND SOUNDING PARAMETERS. AM STRONGLY CONSIDERING A WINTER WEATHER ADVISORY FOR AREAS NW OF A CALDWELL TO CROCKETT LINE FOR OVERNIGHT INTO FRI MORNING. 43 PREV DISCUSSION... /ISSUED 805 PM CST THU DEC 5 2013/ UPDATE... SEE EVENING UPDATE. DISCUSSION... AT 01Z...A COLD FRONT EXTENDED FROM SOUTH CENTRAL LOUISIANA ACROSS THE WESTERN GULF. A VERY TIGHT PRESSURE GRADIENT IS IN PLACE AND WIND SPEEDS ARE APPROACHING ADVISORY CRITERIA. WILL WATCH TRENDS BUT WILL HOLD OFF ON A WIND ADVISORY FOR THE COASTAL COUNTIES FOR NOW. WATER TEMPS HAVE COOLED A BIT SINCE THE LAST FROPA...SO FEEL THERMAL CONTRIBUTION TO WINDS WILL BE LESS THAN PAST COUPLE OF EVENTS. RAP GUIDANCE ALSO SUGGESTS THAT WINDS WILL REMAIN BELOW ADVISORY CRITERIA. POPS ARE RATHER HIGH CONSIDERING THE RADAR LOOKS SO BENIGN AT THE CURRENT TIME. 00Z 850 MB ANALYSIS SHOWS WINDS STILL OUT OF THE SOUTH WITH AN 850 MB FRONT EXTENDING FROM TEXARKANA TO ABOUT LAREDO. ISENTROPIC UPGLIDE HAS NOT REALLY KICKED IN YET AS NORTH WINDS REMAIN VERY SHALLOW. THIS SHOULD CHANGE OVERNIGHT AS THE 850 MB FRONT CLEARS THE COAST. 00Z SOUNDINGS SHOW A SATURATED LAYER FROM THE SURFACE TO 850 MB...AND VERY DRY AIR ABOVE THE SATURATED LAYER. NAM12 AND RAP FORECAST SOUNDINGS CLOSELY MATCH THE 00Z SOUNDINGS. THIS TYPE OF SOUNDING FAVORS DRIZZLE OVER RAIN. EITHER WAY...EXPECT CONDS TO BECOME INCREASINGLY DAMP OVERNIGHT. TEMP FCST LOOKS TO BE ON TRACK. NOT EXPECTING FREEZING TEMPS OVERNIGHT BUT CALDWELL (RWV) IS GETTING CLOSE. CURRENT TEMP AT RWV IS 34 DEGREES WITH A DEW PT OF 30. HAVE SOME CONCERN THAT DEW POINTS NEAR 30 WILL ALLOW FOR SOME EVAPORATIVE COOLING ONCE PRECIP BEGINS AND THEN INSTEAD OF DRIZZLE...WE GET FREEZING DRIZZLE. WILL AGAIN WATCH TRENDS BUT FEEL CURRENT FCST HAS A GOOD HANDLE ON TONIGHT`S TEMP/PRECIP TRENDS. HAVE MADE MINOR CHANGES TO THE GRIDS. NEW ZFP OUT BY 900 PM. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 33 35 27 34 31 / 60 70 10 40 40 HOUSTON (IAH) 38 39 33 38 33 / 40 70 20 50 50 GALVESTON (GLS) 46 48 37 45 40 / 40 70 20 50 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY UNTIL 4 AM CST FRIDAY FOR THE FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...JACKSON...MATAGORDA. GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...43 AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1149 PM EST THU DEC 5 2013 .SYNOPSIS... A SLOW MOVING COLD FRONT MOVES EAST INTO THE APPALACHIANS TONIGHT. THE BOUNDARY CRAWLS ACROSS VIRGINIA ON FRIDAY. ARCTIC HIGH PRESSURE WELL BEHIND THE FRONT WILL WEDGE SOUTH ALONG THE MOUNTAINS SATURDAY...BEFORE INTERACTING WITH PRECIPITATION RETURNING NORTH BY SUNDAY. SOUTHWESTERLY FLOW RETURNS MONDAY BEFORE A STRONGER COLD FRONT ARRIVES LATE MONDAY NIGHT. && .NEAR TERM /THROUGH FRIDAY/... AS OF 745 PM EST THURSDAY... A STRONG COLD FRONT LOCATED TO OUR WEST THIS AFTERNOON FROM CLE TO LEX TO MEM WILL MOVE EAST TONIGHT INTO FRIDAY. WEAK SHORTWAVES MOVE NORTHEAST IN THE WARM SECTION WILL RESULT IN SCATTERED SHOWERS. INCREASED PROBABILITY OF PRECIPITATION IN THE FAR NORTHWEST COUNTY WARNING AREA AND LEANED POPS THIS EVENING INTO TONIGHT TOWARDS A BLEND OF THE LATEST RAP AND RNKWRFARW. THE GFS ALSO SHOWED SOME LIGHT PRECIPITATION ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS INTO SOUTHERN VIRGINIA. THE MAIN BODY OF RAINFALL SHOULD REMAIN WILL REMAIN TO OUR WEST TONIGHT. A VERY WARM AND MUGGY OVERNIGHT EXPECTED WITH READINGS FROM AROUND 50 DEGREES IN THE NORTHWEST MOUNTAINS TO THE LOWER 60S IN THE SOUTHEAST. SURFACE COLD FRONT WILL BE ENTERING THE MOUNTAINS FRIDAY WITH A WAVE OF LOW PRESSURE WHICH DEVELOPS ALONG THE BOUNDARY AND RIPPLE NORTHEAST ACROSS THE REGION. MAIN AXIS OF RAIN SHOULD BE FOCUSED ALONG AND JUST WEST OF THE FRONTAL BOUNDARY FRIDAY. FELT THERE WAS ENOUGH INSTABILITY TO INCLUDE THE MENTION OF AN ISOLATED THUNDERSTORMS MAINLY WEST OF I77. PLAYED HIGH TEMPERATURES CLOSE TO THE ADJMAVBC WITH VALUES FROM THE LOWER 50S IN THE MOUNTAINS TO THE MID 70S IN THE PIEDMONT. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 315 PM EST THURSDAY... NOT A LOT OF CHANGE EARLY ON WITH THE SLOW MOVING COLD FRONT AND ASSOCIATED WAVE CROSSING THE REGION FROM THE NW FRIDAY NIGHT AND SPILLING SOUTH OF THE AREA EARLY SATURDAY. MODELS AGAIN WEAKEN THE AXIS OF LIFT ALONG/BEHIND THE FRONT FRIDAY EVENING WITH HEAVIEST QPF AND HIGHEST POPS ALONG THE WESTERN SLOPES THROUGH LATE EVENING...THEN LESS ALONG/EAST OF THE BLUE RIDGE EXCEPT SE WHERE THE BOUNDARY MAY STALL AND THE LOW LEVEL NE FLOW MAY ENHANCE SHOWERS LATE. STILL APPEARS ENOUGH MOISTURE ACROSS THE NW LATE FRIDAY NIGHT TO WARRANT KEEPING IN SOME LIGHT MIX MENTION AT ELEVATION BUT OVERALL THINK ANYTHING FROZEN AT THIS POINT QUITE SPOTTY ACROSS SE WVA. COLD AIR WILL BE SLIDING IN FROM THE NORTH/WEST ALTHOUGH TEMPS MAY ACTUALLY GET COLDER AFTER DAYBREAK SATURDAY WHEN THE BETTER 85H COLD ADVECTION ARRIVES. GUIDANCE HAS CONTINUED THE TREND FROM YESTERDAY IN PUSHING THE DEEPER MOISTURE TO THE SE SATURDAY AS THE LARGE ARCTIC HIGH BUILDS IN FROM THE NW AND INITIALLY GIVES THE MOISTURE A PUSH. MAY SEE THE ENTIRE CWA GO DRY BY SATURDAY AFTERNOON BUT FOR NOW LEAVING IN SOME POP MAINLY EASTERN HALF THROUGH MIDDAY AND MAINLY FAR SE LATE IN THE DAY. COULD EVEN HAVE SOME CLEARING TAKE PLACE NW PENDING HOW STRONG THE DRY ADVECTION IS SO CUT BACK ON CLOUD COVER SOME NORTH HALF DURING THE AFTERNOON. HIGHS CHILLY WITH LOW LEVEL NORTH/NW FLOW WITH TEMPS 30S WEST TO 40S/NEAR 50 FAR SOUTH. MAIN CONCERN THEN WITH THE POTENTIAL FOR A SIGNIFICANT WINTER EVENT FROM VERY LATE SAT NIGHT INTO SUNDAY AND PERHAPS SUNDAY NIGHT ACROSS THE NORTH. LATEST GUIDANCE HAS AGAIN SLOWED THINGS UP A BIT WITH LOTS OF COLD/DRY AIR SLIDING DOWN EAST OF THE BLUE RIDGE AS THE STRONG WEDGE DEVELOPS WITH THE HIGH BUILDING FARTHER SOUTH. THIS WILL MAKE FOR COLDER TEMPS SAT NIGHT BEFORE THICKENING CLOUDS AND LIGHT PRECIP RETURN FROM THE SOUTH/SW AFTER MIDNIGHT PER ISENTROPIC LIFT AHEAD OF ANOTHER WAVE HEADING UP WEST OF THE MOUNTAINS. LATEST FORECAST SOUNDINGS SHOW DRY AIR HOLDING LONGER WITH PRECIP NOT REACHING INTO THE SOUTHERN HALF OF THE AREA UNTIL AFTER MIDNIGHT AND POINTS NORTH SUNDAY AROUND DAYBREAK. PRECIP THEN LOOKS TO ACCELERATE INTO THE WEDGE SUNDAY MORNING FROM THE SW BUT REMAIN INCONSISTENT IN QPF AMOUNTS WHICH ARE CRITICAL GIVEN COLDER PROFILES FROM 12Z RUNS. HOWEVER MOST SHOWING THE BEST LIFT WITH A WARM FRONT ALOFT TYPE FEATURE THAT DEVELOPS OVER THE CENTRAL/NORTHERN CWA SUNDAY MORNING AND SHIFTS NORTH DURING THE AFTERNOON LEAVING MORE SPOTTY NATURE PRECIP ELSW INTO SUNDAY EVENING. BOTH THE NAM AND GFS ARE COLDER THAN THE EARLIER SOLNS WITH LESS OF A WARM NOSE EARLY ON AND DEEPER LOW LEVEL COLD AIR SUPPORTIVE OF MORE OF A SNOW/SLEET MIX AT THE ONSET ESPCLY HIWAY 460 NORTH. THUS INCLUDING SOME LIGHT ACCUMULATIONS NW SUNDAY MORNING AS THINGS REMAIN BELOW FREEZING AT 85H AND THINGS BECOME MORE ISOTHERMAL UNTIL THE STRONGER WARM ADVECTION ARRIVES IN THE AFTERNOON. SOME SLEET ALSO POSSIBLE ELSW AS THINGS WET BULB DOWN AT THE ONSET BUT THINKING MORE OF A PROLONGED FREEZING RAIN EVENT ESPCLY SRN BLUE RIDGE AND ACROSS THE VA COUNTIES SOUTH OF 460. WEDGE MAY BE ENOUGH TO FORCE TEMPS DOWN ENOUGH TO PRODUCE SOME SPOTTY FZRA INTO NW NC BUT HOLDING OFF GOING THAT COLD ATTM. OTRW FEW CHANGES TO HIGH POPS SUNDAY WITH HIGH POPS FOR LOW QPF SUNDAY NIGHT WHEN THE GREENBRIER VALLEY AND SRN SHENANDOAH VALLEY MAY HOLD ONTO FREEZING RAIN OVERNIGHT. SINCE MOSTLY A 6TH PERIOD AND BEYOND EVENT...WILL HOLD OFF ON HEADLINES FOR NOW AND KEEP MENTION IN THE HWO. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 350 PM EST THURSDAY... COMPLICATED FORECAST CONTINUES THROUGH THE EXTENDED PERIODS AS SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION AT THE SAME TIME ARCTIC AIR CONTINUES TO STREAM SOUTHEASTWARD FROM WESTERN/CENTRAL CANADA INTO THE CENTRAL AND EASTERN U.S. OUR REGION REMAINS ON OR NEAR THE BOUNDARY BETWEEN THE ARCTIC AIR AND THE WARMER AIR TO THE SOUTHEAST...HOWEVER...THROUGH THE LONGER TERM PERIODS IT APPEARS THAT THE ARCTIC AIR WILL WIN OUT ACROSS OUR REGION AND THE FRONTAL WILL FINALLY BE PUSHED INTO THE SE STATES AS THE UPPER FLOW FINALLY BECOMES NW. MON MORNING WE ARE STILL DEALING WITH THE END OF THE POTENTIAL SIGNIFICANT ICING EVENT ADDRESSED IN THE SHORT TERM PERIODS AS THE WEDGE BOUNDARY FINALLY LIFTS INTO NORTHERN VA. MODELS HAVE CONTINUED TO TREND COLDER...WHICH REQUIRES HOLDING ONTO THE -FZRA A FEW MORE HOURS INTO MID-MORNING MONDAY THAN EARLIER INDICATED. WILL CHANGE ALL PRECIPITATION TO -RA BY 15Z MON AS THE FORECAST AREA BRIEFLY MOVES INTO A WARM SECTOR SANDWICHED BETWEEN THE RETREATING COLD AIR WEDGE AND THE NEXT SURGE OF ARCTIC AIR TO THE WEST. THROUGH THE DAYLIGHT HOURS...WE SHOULD SEE ONLY LIQUID PCPN ACROSS THE REGION. BY 06Z TUE...THE NEXT SURGE OF ARCTIC AIR SHOULD MOVE INTO OUR WV COUNTIES AND OUR FAR SW VA CONTINUES. GIVEN THE STRENGTH OF THIS SECOND SURGE OF COLD AIR...WOULD EXPECT -RA TO QUICKLY CHANGE TO -SN FROM WEST TO EAST DURING THE EVENING. AT THE SAME TIME...THE DEEPER MOISTURE IS SHIFTING EAST INTO THE PIEDMONT WHERE AT THIS POINT IT SHOULD STILL BE WARM ENOUGH FOR MOSTLY -RA. THUS...SNOW ACCUMULATIONS OUTSIDE MOUNTAIN UPSLOPE -SHSN EASTERN WV...SHOULD BE MINIMAL...BUT COULD NOT RULE OUT AN INCH OR SO IN SOME SPOTS WEST OF I-81/I-77. THERE IS CONSIDERABLE DISCREPANCY BETWEEN THE GFS/ECMWF IN THIS TIME FRAME...WITH THE ECMWF PUSHING THE MOISTURE WELL EAST OF THE CWA BEFORE ANY APPRECIABLE COLD AIR MOVES INTO THE REGION FROM THE WEST...WHILE THE GFS TRIES TO MOVE YET A THIRD WAVE ALONG THE FRONTAL BOUNDARY ACROSS THE REGION FROM THE SW. GIVEN THE OVERALL CONFLUENT FLOW IN THIS TIME FRAME...NOT EXPECTING ANY SIGNIFICANT PCPN OR MORE IMPORTANTLY WINTER WX ISSUES. AGAIN...HOWEVER...THERE WILL BE MOUNTAIN UPSLOPE -SHSN...WITH MINOR SNOW ACCUMULATIONS EASTERN WV COUNTIES INTO FAR SW VA AND THE NW NC MOUNTAINS. FOR THE REMAINDER OF THE EXTENDED...AT THIS POINT IT APPEARS DRY. THE CENTER OF THE ARCTIC AIR MASS DRIFTS OVER THE REGION BY THU WITH A VERY DRY/COLD AIR MASS. AGAIN...THERE ARE CONSIDERABLE DIFFERENCES BETWEEN THE ECMWF AND GFS WITH RESPECT TO TEMPERATURES IN THIS TIME FRAME. GIVEN THE STRENGTH OF THIS ARCTIC AIR MASS...HAVE LEANED HEAVILY TOWARD THE COLDER GFS. THE COLDEST DAY SHOULD BE THU WHEN THE ARCTIC HIGH IS CENTERED RIGHT OVER THE CWA. WOULD NOT BE THE LEAST SURPRISED TO SEE MIN TEMPERATURES IN THE SINGLE DIGITS IN LOCATIONS SUCH AS LWB. HOWEVER...THE PREVAILING WEST AS OPPOSED TO A STRONG NW-N FLOW ALOFT SHOULD RESULT IN THE COLDER AIR REMAINING NORTH AND WEST OF THE CWA..SO WE SHOULD STAY AOA 20 DEGREES FOR MINS ACROSS THE PIEDMONT. ANY PRECIPITATION WED-FRI SHOULD BE CONFINED TO UPSLOPE MOUNTAIN -SHSN WITH DRIER DOWNSLOPE WEST FLOW EAST OF THE ALLEGHANYS. EVEN ACROSS EASTERN WV...SNOW ACCUMULATIONS SHOULD BE FAIRLY LIMITED WITH OVERALL SNOW ACCUMULATIONS THERE EVEN AN INCH OR LESS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 1145 PM EST THURSDAY... STRONG COLD FRONT WILL BE APPROACHING FROM THE OHIO VALLEY...STALLING WEST OF THE APPALACHIAN MOUNTAINS TONIGHT. A BROAD BAND OF RAIN FROM CENTRAL PENNSYLVANIA TO CENTRAL TENNESSEE WILL BRING RAIN WITH MVFR VISIBILITIES TO KLWB AND KBLF TONIGHT. STRATUS AND FOG WITH SCATTERED SHOWERS IS EXPECTED FOR THE REST OF THE AREA. CEILINGS WERE ALREADY MVFR AT 00Z/7PM. HIGH CONFIDENCE THAT KROA...KBCB...KLYH AND KDAN WILL LOWER TO IFR OR LIFR OVERNIGHT WITH MVFR FOG. LITTLE IMPROVEMENT IS EXPECTED ON FRIDAY. CEILINGS WILL REMAIN IN THE IFR TO MVFR RANGE WITH RAIN BECOMING MORE WIDESPREAD...ESPECIALLY IN THE LATE AFTERNOON AND EVENING. EXTENDED AVIATION...A COLD FRONT WILL MAKE SLOW PROGRESS ACROSS THE AREA LATE FRIDAY...RESULTING IN MVFR AND IFR CONDITIONS IN ADDITION TO WIDESPREAD RAIN SHOWERS...BEFORE THE FRONT PASSES EAST FRIDAY NIGHT INTO SATURDAY MORNING. MAY SEE A BRIEF IMPROVEMENT TO VFR ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH...HOWEVER IFR WILL RETURN SATURDAY NIGHT AS ANOTHER SYSTEM APPROACHES FROM THE SOUTHWEST...BRINGING FREEZING RAIN...SNOW AND SLEET TO THE AREA SUNDAY. AN ARCTIC COLD FRONT WILL MOVE THROUGH ON MONDAY...BRINGING A SLOW IMPROVEMENT TO VFR FOR TUESDAY. HIGH PRESSURE IS EXPECTED TO PROVIDE FAIR WEATHER WITH VFR CONDITIONS FROM TUESDAY THROUGH THURSDAY. && .CLIMATE... WARM TEMPERATURES THE NEXT COUPLE DAYS WILL APPROACH RECORDS AT THE CLIMATE SITES. BELOW ARE THE CURRENT RECORDS. DECEMBER 5 CURRENT RECORD HIGH TEMPERATURES (YEAR) ROA76(2001) LYH76(2001) DAN 75(1982) BCB70(2001) BLF71(2001) LWB68(2001) DECEMBER 5 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR) ROA58(1982) LYH60(1982) DAN57(1982) BCB52(1982) BLF55(1994) LWB53(1994) DECEMBER 6 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR) ROA52(2011) LYH52(2011) DAN60(2011) BCB51(2011) BLF56(2011) LWB 52 (1998) && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/KM NEAR TERM...AMS/KK SHORT TERM...JH LONG TERM...RAB AVIATION...AMS/KK CLIMATE...CF
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
901 PM CST SAT DEC 7 2013 .UPDATE... TEMPERATURES THIS EVENING HAVE RADIATED OUT QUICKLY...REACHING NEAR THE EXPECTED LOWS ALREADY IN A FEW SPOTS. HOWEVER...AN APPROACHING MID DECK OF CLOUDS ASSOCIATED WITH THE WARM ADVECTION FROM THE SYSTEM TO OUR SOUTHWEST WILL PUT A HALT TO THAT TEMP DROP ONCE THEY ARRIVE. WITH RESPECT TO SUNDAY/S SNOW...THE NEW NAM IS NOT BRINGING ANY SURPRISES. IF ANYTHING...IT LOOKS LIKE IT/S GENERATING A TAD MORE PRECIP...ON THE ORDER OF ABOUT 1/2 INCH MORE OF SNOW. THE SURFACE LOW TRACK IS VERY SIMILAR TO THE PREVIOUS RUN AND LOOKS A BIT DEEPER/BETTER ORGANIZED. THE PREVIOUS DISCUSSION BELOW ABOUT THE EVOLUTION OF THE LOW...WHERE THE HEAVIEST SNOW WILL FALL AND WHEN IS STILL VERY MUCH VALID. THE EASTERN AREAS WILL SEE THE MOST DUE TO THE LAKE EFFECT CONTRIBUTION. WITH ONLY ONE NEW MODEL IN AT THIS TIME AND GIVEN IT/S LACK OF SURPRISES...NO CHANGES TO THE LATER PERIODS. && .AVIATION/06Z TAFS/... THE MAIN AVIATION CONCERN DURING THIS PERIOD WILL BE THE SNOW AND LIKELY REDUCTION TO IFR CONDITIONS BY SUNDAY AFTERNOON. THE MAIN AREA OF SNOW WILL PUSH IN DURING THE LATE MORNING OR EARLY AFTERNOON ON SUNDAY AS LOW PRESSURE APPROACHES. HOWEVER...SOME LAKE EFFECT SNOW SHOWERS ARE LIKELY AHEAD OF THAT MAIN AREA FOR KMKE/KENW/KUES. LIGHT AND VARIABLE WINDS WILL BECOME NORTHEAST TO EAST LATE TONIGHT...ALLOWING THE LOWER LAKE EFFECT CLOUDS AND LIGHT SNOW TO REACH THE 3 SOUTHEAST WI TAF SITES BETWEEN 12-15Z SUN. THE LAKE EFFECT WILL COMBINE WITH THE MAIN AREA OF SNOW TO BRING IFR CIGS/VSBYS BY AROUND 18Z AT ALL SITES. THE SNOW SHOULD TAPER OFF AT KMSN BY AROUND 03-04Z MON AND AT THE 3 SOUTHEAST WI TAFS SITES BY AROUND 06Z. ONCE THE SNOW ENDS...WESTERLY WINDS WILL INCREASE TO AROUND 15 KNOTS. && .PREV DISCUSSION... /ISSUED 330 PM CST SAT DEC 7 2013/ SHORT TERM... TONIGHT...FORECAST CONFIDENCE IS HIGH HIGH PRESSURE WILL SLIDE EAST ACROSS THE REGION TONIGHT. HIGH CLOUDS WILL STREAM EAST NORTHEASTWARD INTO THE AREA LATER THIS EVENING AND OVERNIGHT. TEMPERATURES MAY DROP QUICKLY THIS EVENING THROUGH THE SINGLE DIGITS ABOVE ZERO...AS WINDS DECOUPLE WITH THE PASSING HIGH. TEMPERATURES SHOULD THEN BECOME STEADY OR SLOWLY RISE LATER TONIGHT...AS THE CLOUDS MOVE INTO THE AREA. LAKE EFFECT SNOW SHOWER BAND SHOULD SET UP NORTH TO SOUTH ON THE EASTERN SIDE OF LAKE MICHIGAN INTO THE SOUTHERN END OF THE LAKE THIS EVENING. HRRR INDICATING THIS BAND SHOULD GRADUALLY SHIFT TO THE WEST NORTHWEST LATER TONIGHT...POSSIBLY TRACKING INTO THE FAR SOUTHEAST COUNTIES NEAR THE LAKE IN THE 09Z TO 12Z SUNDAY PERIOD. ADDED POPS IN THIS AREA FOR THIS POSSIBILITY. MOST OF THE LAKE EFFECT SNOW SHOWERS SHOULD HOLD OFF UNTIL AFTER 12Z SUNDAY. SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH THE MODELS ARE VERY SIMILAR WITH A WEAK BUT DEVELOPING LOW PRESSURE THAT WILL APPROACH FROM THE PLAINS. THE SFC LOW WILL BECOME CLOSED OFF AT 1015 MB NEAR OR EAST OF KMKE BY 06Z MON AND CONTINUE TO DEEPEN AS IT MOVES THROUGH THE NORTHERN GREAT LAKES AND INTO CANADA ON MON. A LARGE SCALE AND FAIRLY IMPRESSIVE LOW TO MID LEVEL WARM ADVECTION PATTERN WITH WILL OVERSPREAD THE REGION ON SUN WITH SNOW INTENSIFYING LATER IN THE AFTERNOON AND EVENING WHEN THE SHORTWAVE TROUGH APPROACHES FROM THE SW. A CONSENSUS OF THE MODELS ON QPF YIELDS QPF TOTALS OF 0.15-0.22. THE DEPTH OF THE DENDRITE ZONE VARIES ON MODELS BUT HAS TRENDED LESS DEEP FROM YESTERDAY. THEREFORE WILL GO WITH A MODEL CONSENSUS OF SNOW RATIOS CLOSE TO 20 TO 1 VERSUS SOMETHING HIGHER. THIS YIELDS 3 TO 4 INCHES WITH THE EXCEPTION OF 2-3 NEAR THE IL BORDER. THERE HAS BEEN A SLIGHT NWD TREND WITH THE SHORTWAVE TROUGH AND QPF...SO LESSER AMOUNTS NEAR THE IL BORDER IS REASONABLE. LAKE ENHANCED SNOWS THEN NEED TO BE ADDED IN FOR OZAUKEE AND SHEBOYGAN COUNTIES GIVEN THE 1000-850 MB SELY FLOW AND LAKE TO 850 MB TEMP DIFFERENCES OF 14-17C. THE LAKE EFFECT SNOW CHARTS SUGGESTS ADDING AT LEAST 3 INCHES SO FORECASTING 4-7 INCHES OF SNOW IN SHEBOYGAN AND NRN OZAUKEE COUNTIES. IF GREATER LAKE ENHANCED SNOW IS EXPECTED A WINTER STORM WARNING MAY BE NEEDED. A WINTER WX ADVISORY IS IN EFFECT FOR ALL OF THE CWA FOR THIS SNOW EVENT. BRISK WESTERLY WINDS AND COLD ADVECTION TO PREVAIL ON MON WITH THE ARCTIC AIRMASS RETURNING AFTER HIGHS IN THE 20S ON SUN. WIND GUSTS TO 25 MPH COMBINED WITH A POWDERY SNOW PACK SHOULD RESULT IN AREAS OF BLOWING AND DRIFTING SNOW THAT WILL LIKELY CAUSE SOME PROBLEMS THROUGHOUT THE DAY FOR TRAVEL. A SHORTWAVE SFC RIDGE WILL MOVE ACROSS SRN WI MON NT WITH RADIATIONAL COOLING AND ARCTIC AIR MAKING FOR ANOTHER VERY COLD NIGHT. SWLY WINDS WILL DEVELOP TOWARD MORNING AS AN ALBERTA CLIPPER MOVES ACROSS THE NORTHERN GREAT LAKES. WILL LIKELY ONLY SEE SCT-BKN CLOUD COVER FROM IT ON TUE WITH THE SNOW REMAINING OVER NRN WI. DESPITE SWLY WINDS...HIGH TEMPS TO ONLY REACH INTO THE TEENS. THE BRISK WINDS HOWEVER WILL MAINTAIN VERY COLD WIND CHILLS FOR MON-TUE. LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM. A COUPLE WEAK CLIPPERS WILL BRING ONLY SMALL CHANCES OF LIGHT SNOW OR FLURRIES FOR TUE NT INTO POSSIBLY WED AND AGAIN FOR THU. ARCTIC AIR WILL REMAIN OVER THE AREA INTO THU NT. LOW PRESSURE WILL THEN APPROACH FROM THE NRN PLAINS FOR LATE IN THE WEEK WITH WARM ADVECTION BRINGING MODERATING TEMPS AND CHANCES OF LGT SNOW. AVIATION/00Z TAFS/... VFR CONDITIONS ARE EXPECTED TONIGHT ACROSS TAF SITES. WEST NORTHWEST WINDS WILL GRADUALLY WEAKEN AND BECOME LIGHT TO CALM TONIGHT...WITH HIGH CLOUDS MOVING INTO THE AREA BY LATER TONIGHT. A LAKE EFFECT SNOW BAND WILL MOVE NORTHWARD TO KENOSHA AROUND 12Z SUNDAY...AND MILWAUKEE/WAUKESHA BY 15Z SUNDAY. THE LIGHT SNOW SHOWERS WITH THE BAND WILL LINGER FOR A 3 TO 5 HOUR PERIOD THEREAFTER...WITH MVFR/IFR CEILINGS AND VISIBILITIES OF 2 TO 3 MILES. LIGHT ACCUMULATIONS OF UP TO 0.5 INCHES IS POSSIBLE. EAST SOUTHEAST WINDS WILL INCREASE SUNDAY. THE LIGHT TO MODERATE SNOW WITH THE LOW PRESSURE SYSTEM MOVING NORTHEAST THROUGH THE REGION WILL REACH MADISON BY 15Z SUNDAY...AND THE EASTERN SITES BY 18Z SUNDAY. THE SNOW WILL BECOME ALL LIGHT BETWEEN 04Z AND 06Z MONDAY WEST TO EAST ACROSS TAF SITES...THEN ENDING BETWEEN 09Z AND 12Z MONDAY SOUTHWEST TO NORTHEAST. WINDS WILL VEER SOUTHWEST BY 06Z MONDAY...AND WEST BY 12Z MONDAY. WINDS WILL BECOME GUSTY LATE SUNDAY NIGHT INTO MONDAY...WITH SOME BLOWING AND DRIFTING SNOW. CEILINGS/VISIBILITIES AT OR BELOW ALTERNATE MINIMUMS ARE EXPECTED...WITH SOME 1/2 MILE VISIBILITIES POSSIBLE AT TIMES. THE SNOW IS EXPECTED TO BE OF THE LIGHT AND FLUFFY VARIETY. SNOWFALL RATES OF 1/4 TO 1/2 INCH PER HOUR ARE EXPECTED...WITH LOCALLY HIGHER RATES POSSIBLE. TOTAL SNOW ACCUMULATIONS OF 3 TO 4 INCHES ARE EXPECTED...HIGHEST AT MADISON/MILWAUKEE AND LOWEST AT KENOSHA. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM NOON SUNDAY TO 6 AM CST MONDAY FOR WIZ046-047-051-052-056>060-062>072. LM...NONE. && $$ UPDATE...DAVIS TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1243 AM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 DEEP TROUGHING ORIENTED FROM EASTERN CANADA ACROSS THE GREAT LAKES AND WEST TO THE SOUTHWEST CONUS IS REINFORCED THROUGHOUT THE UPCOMING WEEK. COLD AIRMASS MAY FINALLY MAY START TO RELAX BY NEXT WEEKEND AS FLOW ALOFT BECOMES MORE ZONAL. FLOW PATTERN THIS WEEK REMAINS ACTIVE ACROSS THE UPPER LAKES. A COUPLE OF SYSTEMS WILL CROSS THE AREA WITH WIDESPREAD SYSTEM SNOWS. MOST SIGNIFICANT OF THESE WILL OCCUR SUNDAY NIGHT AS SHORTWAVE/PV ANAMOLY CROSSING NEVADA/UTAH THIS AFTN/EVENING HEADS OUT INTO CNTRL PLAINS SUNDAY AFTN THEN LIFTS ACROSS UPPER GREAT LAKES SUNDAY NIGHT. SLIGHT WARM AIR ADVECTION...RELATIVE TERM IN THIS AIRMASS...OCCURS OVER SOUTH CENTRAL AND EASTERN CWA SUNDAY EVENING WITH PVA/DEEP LAYER FORCING THROUGH REST OF NIGHT. CROSS-SECTIONS INDICATE VERY SHALLOW FGEN FORCING BLO H9...MAINLY SOUTH AND EAST. MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV TO RESULT IN HEAVIER BANDED SNOW THOUGH. ENHANCEMENT TO SYSTEM SNOW MAY OCCUR NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE/E WINDS IN LOW-LEVELS WITH TEMPS AT INVERSION TOP OF H85 AROUND -10C /LK MICHIGAN WATER TEMPS ARE AROUND +5C/. TRICK IS HOW LONG FAVORABLE WIND DIRECTION PERSISTS AND WHETHER THERE IS TOO MUCH SHEAR IN LAKE CONVECTIVE LAYER TO OFFSET THIS. EXPECT GENERAL 2-4" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S 17-19:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEMED TOUGHER TO ACHIEVE AS BULK OF LIFT WILL BE OCCURRING AT TEMPS LESS THAN -20C. SLR/S WILL PROBABLY BE EVEN LOWER HEADING FARTHER NORTH INTO UPR MICHIGAN...SO SNOW AMOUNTS OF AN INCH MAYBE TWO ARE EXPECTED CLOSER TO LK SUPERIOR SHORE. ISSUED WINTER WEATHER ADVY FOR THE SYSTEM SNOW. BASED ON SREF PLUMES AND FCST POPS...VALID TIME OF ADVY FAR SCNTRL WILL START LATE SUNDAY AFTN AND GO THROUGH DAYBREAK ON MONDAY. ADVY FOR ZONES TO THE EAST WILL START AND END A FEW HOURS LATER. LOW PRESSURE SYSTEM LIFTS TO NORTHEAST OF LK SUPERIOR BY 18Z ON MONDAY AND THIS WILL USHER IN ANOTHER RETURN TO THE COLD AND WINDY WEATHER THAT OCCURRED LATE THIS LAST WEEK INTO TODAY. AND YES...LAKE EFFECT SNOWS...HEAVY AT TIMES...WILL RAMP UP AGAIN IN THE AREAS FAVORED BY WNW-W FLOW. SO...ONCE AGAIN...KEWEEENAW PENINSULA WILL BE IN LINE FOR HEAVY LK EFFECT SNOWS. SOUNDINGS IN WAKE OF THE LOW PRESSURE INDICATE MOIST/UNSTABLE PROFILE TO H7 WITH SHARP CONVERGENCE DEVELOPING ACROSS KEWEENAW BY MID MORNING MONDAY AND CONTINUING THROUGH AT LEAST LATE EVENING ON MONDAY NIGHT. SIMILAR TO THURSDAY...IF WESTERLY FLOW CAN PERSIST IN ONE AREA...LEADING TO STRONG CONVERGENCE...FOOT PLUS AMOUNTS WILL BE POSSIBLE ACROSS CNTRL HOUGHTON COUNTY... AFFECTING PAINESDALE...ATLANTIC MINE...HOUGHTON AND HANCOCK AND POSSIBLY AS FAR NORTH AS CALUMET AND MOHAWK. LAKE EFFECT HEADLINES ARE RUNNING THEIR COURSE CURRENTLY...SO DID NOT WANT TO PUT UP ANOTHER LK EFFECT SNOW WATCH AT THIS TIME. WILL LET MID SHIFT ASSESS THIS POTENTIAL. MAIN ISSUE AWAY FM THE INCREASING LK EFFECT BY MONDAY AFTN WILL BE ANOTHER BLAST OF COLD TEMPS AND LOWERING WIND CHILL READINGS. DOES APPEAR THAT AS STRONGER SHORTWAVE/PRETTY DECENT AREA OF H7-H5 Q-VECTOR CONVERGENCE ARRIVES LATER MONDAY NIGHT...BLYR WINDS BACK SW ENOUGH TO DISRUPT HEAVIER SNOW ON THE KEWEENAW. THIS MAY PROVIDE A GOOD BREAK POINT FOR WHATEVER HEADLINE IS ISSUED FOR MONDAY AND MONDAY EVENING...THOUGH THERE IS A CHANCE THE HEAVIER SNOW BANDS WILL JUST MAKE INTO KEWEENAW COUNTY BEFORE STALLING OUT. TOUGH TO SAY AT THIS POINT. SOUNDINGS ELSEHWERE INDICATE ENOUGH MOISTENING AND LIFT TO INCREASE POPS FOR THE SYSTEM...ESPECIALLY NORTH HALF. SNOW AMOUNTS FM THE SYSTEM WILL BE ON THE LGT SIDE...LESS THAN AN INCH MAINLY. OTHER IMPACT FM THE SHORTWAVE WILL BE FOR TEMPS TO TRY TO RISE SOME LATER MONDAY NIGHT AS THE WINDS INCREASE. THIS MAKES FOR TRICKY WIND CHILL FORECAST. CURRENT FCST FOR WINDS AND TEMPS DOES SUGGEST THAT WESTERN HALF OF CWA MAY SEE WIND CHILL CRITERIA BE MET AT TIMES ON MONDAY NIGHT INTO TUESDAY MORNING. LAST IMPACT FROM THE SYSTEM WILL BE TO PUSH STRONGER SFC TROUGH SOUTH ACROSS LK SUPERIOR RESULTING IN MORE OF A NW WIND IN BLYR FOR TUESDAY/TUESDAY NIGHT. USED LK EFFECT CLIMATOLOGY POPS TO BRING HIGHER POPS TO AREAS FAVORED BY WNW FLOW SUCH AS ONTONAGON COUTNY AND ALSO IN THE EASTERN CWA...MAINLY EAST OF MUNISING AND TO THE NORTH OF NEWBERRY. IN WAKE OF THE TROUGH PASSAGE...COLDEST AIR OF WEEK POURS ACROSS WITH H85 TEMPS DOWN TO AROUND -25C TUESDAY NIGHT INTO WEDNESDAY. MAY HAVE MORE WIND CHILL ISSUES TUESDAY NIGHT INTO WEDNESDAY AS INLAND TEMPS FALL BLO ZERO AND WINDS STAY UP BEHIND THE TROUGH. COLDEST DAY OF THE WEEK FOR WEDNESDAY WITH MAX TEMPS OVER INLAND WEST POSSIBLY STAYING AT OR BLO ZERO THE ENTIRE DAY. COLDEST NIGHT OF THE WEEK LIKELY ON WEDNESDAY NIGHT. AS WINDS GO CALM MAY SEE MINS LESS THAN 20 BLO ZERO. SLIGHT WARMING TREND FOR LATE THIS WEEK...BUT STILL QUITE A BIT BLO NORMAL FOR DAYTIME HIGHS. WEST/SOUTHWEST FLOW LK EFFECT STAYS IN PLACE ON KEWEENAW THURSDAY BUT THEN SHOULD REORIENT TO MORE NNW-N FLOW AREAS ON FRIDAY AS ANOTHER SFC TROUGH SWINGS ACROSS. MAY SEE SOME SYSTEM SNOW THURSDAY NIGHT INTO FRIDAY AHEAD OF THAT TROUGH BUT THERE ARE SOME TIMING ISSUES THERE STILL...SO WILL JUST HAVE LOW CHANCE POPS FOR NOW. DID BUMP UP THE CONSENSUS POPS FOR THE LK EFFECT AREAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR MIZ002-004-009>011-084. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR MIZ003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SAT DEC 7 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 DEEP TROUGHING ORIENTED FROM EASTERN CANADA ACROSS THE GREAT LAKES AND WEST TO THE SOUTHWEST CONUS IS REINFORCED THROUGHOUT THE UPCOMING WEEK. COLD AIRMASS MAY FINALLY MAY START TO RELAX BY NEXT WEEKEND AS FLOW ALOFT BECOMES MORE ZONAL. FLOW PATTERN THIS WEEK REMAINS ACTIVE ACROSS THE UPPER LAKES. A COUPLE OF SYSTEMS WILL CROSS THE AREA WITH WIDESPREAD SYSTEM SNOWS. MOST SIGNIFICANT OF THESE WILL OCCUR SUNDAY NIGHT AS SHORTWAVE/PV ANAMOLY CROSSING NEVADA/UTAH THIS AFTN/EVENING HEADS OUT INTO CNTRL PLAINS SUNDAY AFTN THEN LIFTS ACROSS UPPER GREAT LAKES SUNDAY NIGHT. SLIGHT WARM AIR ADVECTION...RELATIVE TERM IN THIS AIRMASS...OCCURS OVER SOUTH CENTRAL AND EASTERN CWA SUNDAY EVENING WITH PVA/DEEP LAYER FORCING THROUGH REST OF NIGHT. CROSS-SECTIONS INDICATE VERY SHALLOW FGEN FORCING BLO H9...MAINLY SOUTH AND EAST. MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV TO RESULT IN HEAVIER BANDED SNOW THOUGH. ENHANCEMENT TO SYSTEM SNOW MAY OCCUR NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE/E WINDS IN LOW-LEVELS WITH TEMPS AT INVERSION TOP OF H85 AROUND -10C /LK MICHIGAN WATER TEMPS ARE AROUND +5C/. TRICK IS HOW LONG FAVORABLE WIND DIRECTION PERSISTS AND WHETHER THERE IS TOO MUCH SHEAR IN LAKE CONVECTIVE LAYER TO OFFSET THIS. EXPECT GENERAL 2-4" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S 17-19:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEMED TOUGHER TO ACHIEVE AS BULK OF LIFT WILL BE OCCURRING AT TEMPS LESS THAN -20C. SLR/S WILL PROBABLY BE EVEN LOWER HEADING FARTHER NORTH INTO UPR MICHIGAN...SO SNOW AMOUNTS OF AN INCH MAYBE TWO ARE EXPECTED CLOSER TO LK SUPERIOR SHORE. ISSUED WINTER WEATHER ADVY FOR THE SYSTEM SNOW. BASED ON SREF PLUMES AND FCST POPS...VALID TIME OF ADVY FAR SCNTRL WILL START LATE SUNDAY AFTN AND GO THROUGH DAYBREAK ON MONDAY. ADVY FOR ZONES TO THE EAST WILL START AND END A FEW HOURS LATER. LOW PRESSURE SYSTEM LIFTS TO NORTHEAST OF LK SUPERIOR BY 18Z ON MONDAY AND THIS WILL USHER IN ANOTHER RETURN TO THE COLD AND WINDY WEATHER THAT OCCURRED LATE THIS LAST WEEK INTO TODAY. AND YES...LAKE EFFECT SNOWS...HEAVY AT TIMES...WILL RAMP UP AGAIN IN THE AREAS FAVORED BY WNW-W FLOW. SO...ONCE AGAIN...KEWEEENAW PENINSULA WILL BE IN LINE FOR HEAVY LK EFFECT SNOWS. SOUNDINGS IN WAKE OF THE LOW PRESSURE INDICATE MOIST/UNSTABLE PROFILE TO H7 WITH SHARP CONVERGENCE DEVELOPING ACROSS KEWEENAW BY MID MORNING MONDAY AND CONTINUING THROUGH AT LEAST LATE EVENING ON MONDAY NIGHT. SIMILAR TO THURSDAY...IF WESTERLY FLOW CAN PERSIST IN ONE AREA...LEADING TO STRONG CONVERGENCE...FOOT PLUS AMOUNTS WILL BE POSSIBLE ACROSS CNTRL HOUGHTON COUNTY... AFFECTING PAINESDALE...ATLANTIC MINE...HOUGHTON AND HANCOCK AND POSSIBLY AS FAR NORTH AS CALUMET AND MOHAWK. LAKE EFFECT HEADLINES ARE RUNNING THEIR COURSE CURRENTLY...SO DID NOT WANT TO PUT UP ANOTHER LK EFFECT SNOW WATCH AT THIS TIME. WILL LET MID SHIFT ASSESS THIS POTENTIAL. MAIN ISSUE AWAY FM THE INCREASING LK EFFECT BY MONDAY AFTN WILL BE ANOTHER BLAST OF COLD TEMPS AND LOWERING WIND CHILL READINGS. DOES APPEAR THAT AS STRONGER SHORTWAVE/PRETTY DECENT AREA OF H7-H5 Q-VECTOR CONVERGENCE ARRIVES LATER MONDAY NIGHT...BLYR WINDS BACK SW ENOUGH TO DISRUPT HEAVIER SNOW ON THE KEWEENAW. THIS MAY PROVIDE A GOOD BREAK POINT FOR WHATEVER HEADLINE IS ISSUED FOR MONDAY AND MONDAY EVENING...THOUGH THERE IS A CHANCE THE HEAVIER SNOW BANDS WILL JUST MAKE INTO KEWEENAW COUNTY BEFORE STALLING OUT. TOUGH TO SAY AT THIS POINT. SOUNDINGS ELSEHWERE INDICATE ENOUGH MOISTENING AND LIFT TO INCREASE POPS FOR THE SYSTEM...ESPECIALLY NORTH HALF. SNOW AMOUNTS FM THE SYSTEM WILL BE ON THE LGT SIDE...LESS THAN AN INCH MAINLY. OTHER IMPACT FM THE SHORTWAVE WILL BE FOR TEMPS TO TRY TO RISE SOME LATER MONDAY NIGHT AS THE WINDS INCREASE. THIS MAKES FOR TRICKY WIND CHILL FORECAST. CURRENT FCST FOR WINDS AND TEMPS DOES SUGGEST THAT WESTERN HALF OF CWA MAY SEE WIND CHILL CRITERIA BE MET AT TIMES ON MONDAY NIGHT INTO TUESDAY MORNING. LAST IMPACT FROM THE SYSTEM WILL BE TO PUSH STRONGER SFC TROUGH SOUTH ACROSS LK SUPERIOR RESULTING IN MORE OF A NW WIND IN BLYR FOR TUESDAY/TUESDAY NIGHT. USED LK EFFECT CLIMATOLOGY POPS TO BRING HIGHER POPS TO AREAS FAVORED BY WNW FLOW SUCH AS ONTONAGON COUTNY AND ALSO IN THE EASTERN CWA...MAINLY EAST OF MUNISING AND TO THE NORTH OF NEWBERRY. IN WAKE OF THE TROUGH PASSAGE...COLDEST AIR OF WEEK POURS ACROSS WITH H85 TEMPS DOWN TO AROUND -25C TUESDAY NIGHT INTO WEDNESDAY. MAY HAVE MORE WIND CHILL ISSUES TUESDAY NIGHT INTO WEDNESDAY AS INLAND TEMPS FALL BLO ZERO AND WINDS STAY UP BEHIND THE TROUGH. COLDEST DAY OF THE WEEK FOR WEDNESDAY WITH MAX TEMPS OVER INLAND WEST POSSIBLY STAYING AT OR BLO ZERO THE ENTIRE DAY. COLDEST NIGHT OF THE WEEK LIKELY ON WEDNESDAY NIGHT. AS WINDS GO CALM MAY SEE MINS LESS THAN 20 BLO ZERO. SLIGHT WARMING TREND FOR LATE THIS WEEK...BUT STILL QUITE A BIT BLO NORMAL FOR DAYTIME HIGHS. WEST/SOUTHWEST FLOW LK EFFECT STAYS IN PLACE ON KEWEENAW THURSDAY BUT THEN SHOULD REORIENT TO MORE NNW-N FLOW AREAS ON FRIDAY AS ANOTHER SFC TROUGH SWINGS ACROSS. MAY SEE SOME SYSTEM SNOW THURSDAY NIGHT INTO FRIDAY AHEAD OF THAT TROUGH BUT THERE ARE SOME TIMING ISSUES THERE STILL...SO WILL JUST HAVE LOW CHANCE POPS FOR NOW. DID BUMP UP THE CONSENSUS POPS FOR THE LK EFFECT AREAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1156 PM EST SAT DEC 7 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...SRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002- 004-009>011-084. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST SUNDAY FOR MIZ003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM SUNDAY TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CST Sat Dec 7 2013 .UPDATE: Issued at 944 PM CST Sat Dec 7 2013 Several narrow snow bands have developed this evening across southwest Missouri in an area of strong mid level frontogenetical forcing and low/mid level warm advection ahead of a short wave moving through the southern plains. Snow is reaching the ground in and there are areas that have a dusting. The latest RAP and HRRR runs increase the forcing and shift it northeastward parallelling I-44 during the overnight hours and into the St. Louis metro area. This seems reasonable based on observed trends. The only question is the coverage and whether a wider more solitary band will evolve or whether it will remain with several narrow bands. At this time I have increased the pops within this corridor but only mentioned scattered snow showers due to the uncertainty in the coverage evolution. Some areas could certainly pick up a dusting to half inch beneath them. If the coverage expands I will probably need to boost pops into the likely category before the evening is over. Glass && .SHORT TERM: (Through Sunday Evening) Issued at 301 PM CST Sat Dec 7 2013 Strong shortwave dipping into the base of the upper level trof across the western CONUS will move across the Four Corners tonight and emerge into the Plains on Sunday morning. Impressive warm advection forecast to develop ahead of the shortwave with light qpf noted on all model guidance to march northeast across the CWA from late tonight through Sunday afternoon. Believe this is one of those high PoP/low QPF events. Precipitation type is not clear cut...as lack of ice crystal formation is noted on model soundings. I also note that there is a steady stream of mid and high level clouds streaming northeast from Texas. Wonder if the ice crystals from the higher clouds will lead to a seeder/feeder situation, ultimately allowing the precipitation to fall as more snow or snow grains rather than freezing drizzle late tonight and tomorrow morning. Tomorrow afternoon the best lift will be moving northeast and the lower atmosphere will be warming so precipitation will likely turn to areas of freezing drizzle that may continue into the evening. Overall believe snowfall amounts will remain under an inch and any freezing drizzle will only produce a light glaze. Will let the evening and overnight shifts take a look at the 00Z model data to determine the need, if any, for headlines on Sunday. CVKING .LONG TERM: (Sunday Night through Next Saturday) Issued at 301 PM CST Sat Dec 7 2013 Cold front will progress southeast across the CWA late Sunday night, reinforcing the cold for the beginning of the work week. Next shortwave moves into the Plains Monday night an CWA will be in a favorable area of synoptic lift provided by the right entrance region of the jet streak to our northeast. This may ultimately provide another chance of light snow south of Interstate 70. Have kept slight chance PoPs at this time. Extended forecast remains dry and cold with cold front passages Wednesday and Friday. CVKING && .AVIATION: (For the 06z TAFs through 06z Sunday Night) Issued at 1139 PM CST Sat Dec 7 2013 Have added mention of SN early in the period for STL/SUS/CPS for approaching band of SN. This initial band is expected to be short lived as it moves nwd thru the area. Also added light SN at COU/UIN just before sunrise, but there is some uncertainty how intense the SN will be. After a lull in precip, prev TAF forecast still appears on track with another round mid to late morning and gradually changing to FZDZ. Same uncertainties exist regarding timing of change over and time when FZDZ will end. Guidance continues to suggest that FZFG may be an issue as precip comes to an end as low clouds settle into the region. For now, have visbys at 5SM, but if trends continue, visbys may need to be lowered. && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
322 AM CST SUN DEC 8 2013 .DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. SNOW AT ALL TAF SITES...BUT ENDING BY 09/00Z AT KOFK...01-02Z AT KLNK/KOMA. MVFR CLOUDS MAY EVENTUALLY BECOME IFR BY 10Z AS HEAVIER LIFT MOVES INTO THE REGION...THEN BACK TO MVFR BY 16-18Z. EASTERLY WINDS BECOME SOUTHEAST BUT LESS THAN 12 KNOTS...BUT THEN BECOME LIGHTER AND VARIABLE AS A SURFACE TROUGH APPROACHES BY 19-21Z...THEN NORTHWEST BY 22-24Z. ACCUMULATIONS AT TAF SITES IN THE 3 TO 4 INCHES. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1254 AM EST SUN DEC 8 2013 .SYNOPSIS... A COLD FRONT WILL STALL SOUTH OF THE REGION INTO SUNDAY THEN LIFT BACK NORTH THROUGH THE AREA SUNDAY NIGHT. ANOTHER COLD FRONT WILL APPROACH FROM THE WEST MONDAY AND CROSS EARLY TUESDAY. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY INTO FRIDAY. WEAK LOW PRESSURE WILL DEVELOP NEAR THE COAST LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1250 AM SUNDAY...PRECIPITATION IS LIMITED TO THE IMMEDIATE COASTAL AREAS AND HAVE MADE CHANGES TO THE POPS TO REFLECT THE CURRENT RADAR TRENDS WITH MINIMAL POPS INLAND. LATEST 3 KM HRRR AND RAP INCREASES PRECIPITATION INLAND AFTER 12Z WITH INCREASING ISENTROPIC LIFT MOVING INLAND. NO OTHER BIG CHANGES TO THE FORECAST AS TEMPERATURES WILL REMAIN FAIRLY STEADY GIVEN THE CLOUDINESS AND N/NE WINDS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... AS OF 215 PM SATURDAY...ISENT LIFT WILL GRAD LIFT N OF REGION SUNDAY BUT STILL LOOKS LIKE DECENT CVRG OF RAIN/DRIZZLE ESPCLY EARLY ALL AREAS AND ACROSS THE N LATER. DID NOT CHANGE POPS WHICH HAVE LIKELY ALL AREAS EARLY...DIMINISHING TO CHC S AS BEST LIFTS SHIFTS TO THE N. COOL NE FLOW WILL PERSIST INLAND WITH HIGHS IN THE 40S...ALONG THE CST MAY SEE SOME LOW TO MID 50S AS LOW LVL FLOW BECOMES A LITTLE MORE ONSHORE. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS OF 330 PM SAT...AN UPPER TROUGH WILL REMAIN CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT REMAINS CENTERED OVER FLORIDA AND THE SE CONUS...PLACING EASTERN NC IN SW FLOW ALOFT THROUGH EARLY IN THE WEEK. WEAK SFC LOW/WARM FRONT WILL DEVELOP SUN NIGHT AND MOVE NNE WITH RETURN SW FLOW TAKING OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. RAIN CHANCES WILL END DRASTICALLY SUN NIGHT...THOUGH FCST SNDGS INDICATE OVERCAST LOW CLOUDS/MIST AND POSSIBLE PATCHY DRIZZLE SUN NIGHT WITH WARM FRONT MOVING NORTHWARD. MAY SEE SOME SUNSHINE BREAK THROUGH ON MONDAY AS SW WINDS BRING WARMING TEMPS INTO THE MID 60S NORTHWEST TO NEAR 70 SOUTH. RAIN EXPECTED ONCE AGAIN MON NIGHT INTO TUE AS A FRONTAL BOUNDARY PUSHES THROUGH FROM THE NORTH. PRECIP CHANCES INC FROM NORTH TO SOUTH BEGINNING MON NIGHT. LOTS OF MOISTURE AVAILABLE WITH THIS FRONTAL SYSTEM AS PLENTY OF GULF OF MEXICO MOISTURE IN SW FLOW ALOFT. MAINTAINED LIKELY POPS DUE TO STRONG AGREEMENT AMONGST OPER MODEL RUNS BETWEEN GFS/ECMWF AND ECMWF ENSEMBLE MEAN. FOR HIGH TEMPS TUE...LOW CONFIDENCE AS TIMING OF THE FRONTAL BOUNDARY THROUGH E NC WILL DICTATE WHETHER WARMER TEMPS NEAR 70 ARE REALIZED OR TEMPS REMAIN IN THE 50S. GFS/NAM ARE SLOWER WITH THE FRONT BRINGING IT THROUGH TUE AFTERNOON...WHILE FASTER ECMWF PUSHES THE FRONT THROUGH BY TUE MORNING. IF SLOWER GFS/NAM SOLN VERIFY COULD SEE SOME THUNDERSTORMS AS INSTABILITY WILL BE PRESENT WITH SOLAR HEATING DURING THE DAY TUE. FOR NOW...HAVE COMPROMISED AND HAVE COOLER 50S NORTH TO NEAR 70 ON THE CRYSTAL COAST AND KEPT THUNDER OUT OF THE FCST. TEMPS SHOULD EXHIBIT A NON- DIURNAL CURVE AS WARMEST READINGS REALIZED EARLY TUE. RAIN WILL QUICKLY END BY TUES EVENING FROM NW TO SE AS THE FRONT SWEEPS OFFSHORE. MUCH COOLER/DRIER AIR WILL FILTER IN BEHIND THE FRONT WED/THURS WITH HIGHS IN THE UPPER 40S/LOW 50S WITH LOWS BELOW FREEZING MOST AREAS INLAND. MODEST AGREEMENT THURS AFTERNOON WITH A WEAK LOW DEVELOPING OFFSHORE OF SC/GA WHICH MAY WRAP AROUND SOME CLOUDS INTO THE EASTERN HALF OF THE CWA...THUS MAINTAINED SLIGHT CHANCE POPS WED NIGHT/THURS FOR THE COAST. NAEFS POPS AND ECM SOLN REMAIN MAINLY DRY HOWEVER SO AM DISCOUNTING THE WETTER GFS SOLN. ANY OFFSHORE LOW WILL SHIFT WELL AWAY FROM THE AREA LATE THUR WITH A RETURN TO DRY CONDITIONS OVER THE AREA THROUGH FRI...WITH TEMPS STILL 5-8 F BELOW NORMAL FOR MID DECEMBER. 07/12Z OPERATIONAL RUNS OF THE GFS/ECM INDICATE NEXT POSSIBLE STORM SYSTEM MOVING UP OUT OF THE GOM LATE IN THE WEEK AS NEXT SHORTWAVE DIGS THROUGH THE CENTRAL CONUS...SO HAVE INCLUDED CHANCE POPS FOR LATE IN THE PERIOD INTO NEXT WEEKEND. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 00Z MONDAY/... AS OF 1250 PM SAT...PRECIPITATION IS NOW LIMITED TO COASTAL SECTIONS WITH MVFR CEILINGS AT KEWN AND KOAJ WITH VFR AT BOTH KISO AND KPGV CURRENTLY. WITH INCREASING ISENTROPIC LIFT AFTER 12Z...HAVE TRENDED CEILINGS DOWN TO IFR AT ALL TAF SITES THROUGH THE DAY SUNDAY. LONG TERM /SUNDAY NIGHT THROUGH THU/... AS OF 330 PM SAT..A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER AND PRECIP CHANCES DIMINISHING. HOWEVER...SOUNDINGS INDICATE PLENTY OF LOW LEVEL MOISTURE REMAINING IN PLACE BRINGING POSSIBLE LIFR CIGS AND BR TO THE TERMINALS...ALONG WITH SOME PATCHY DRIZZLE. LOW CLOUDS SHOULD LIFT MON AS SW FLOW INCREASES. ANOTHER COLD FRONT CROSSES THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS MON NIGHT THROUGH TUE. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT THROUGH MID TO LATE WEEK WITH VFR RETURNING IN MOSTLY SUNNY SKIES. && .MARINE... SHORT TERM /THROUGH SUN/... AS OF 1255 AM SUNDAY...GUSTY N/NNE WINDS CONTINUE OVER THE COASTAL WATERS AND SOUNDS. WIND GUSTS CURRENTLY UP TO 30 KNOTS AT THE BUOY 13 MILES EAST OF OREGON INLET. SEAS THERE HAVE ALSO BUILT TO 9 FEET. MADE JUST MINOR TWEAKS TO THE CURRENT FORECAST AS THESE TRENDS SHOULD CONTINUE OVERNIGHT AND THRU SUNDAY. LONG TERM /SUNDAY NIGHT THROUGH THU/... AS OF 330 PM SAT...WEAK SURFACE LOW MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME W ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS SUN NIGHT. SW WINDS EXPECTED MON NIGHT AND PEAK AROUND 15 KT BY EVENING. WINDS SHIFT N AND INCREASE 15-20 KT DUE TO POST- FRONTAL CAA SURGE ASSOCIATED WITH STRONG HIGH PRESSURE BUILDING OVER THE WATERS BEGINNING TUES AFTERNOON AND LASTING INTO WED. SEAS BUILD 4-7 FT LATE TUES/TUES NIGHT. REINFORCING COLD AIR SURGE POSSIBLE BY THUR KEEPING SCA CONDITIONS A THREAT FOR MUCH OF THE COASTAL WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ135. SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ150- 152-154. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ156- 158. && $$ SYNOPSIS...RF NEAR TERM...CTC SHORT TERM...RF LONG TERM...TL AVIATION...CTC/TL MARINE...CTC/TL/LEP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
132 AM CST SUN DEC 8 2013 .UPDATE... ISSUED AT 132 AM CST SUN DEC 8 2013 LIGHT SNOW IS RAPIDLY DEVELOPING AND/OR SPREADING INTO LOCATIONS ALONG/WEST OF THE MISSISSIPPI RIVER. IN FACT...EVEN HERE AT OUR OFFICE BEGINNING TO SEE SOME VERY SMALL FLAKES FALL. HAVE UPDATED THE FORECAST TO SPREAD PRECIPITATION CHANCES QUICKER INTO THE AREA. APPEARS MUCH OF THE SNOW DURING THE EARLY MORNING HOURS WILL BE LIGHT...LIKELY WITH VISIBILITIES ON THE ORDER OF 2 MILES. WSW ALSO UPDATED TO RELAY THE SNOW STARTING UP QUICKER. RAP SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION THUS FAR. AVIATION DISCUSSION UPDATED BELOW AS WELL TO ACCOUNT FOR THE QUICKER START UP OF THE SNOW. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 206 PM CST SAT DEC 7 2013 FORECAST FOCUS IS ON SNOW POTENTIAL LATE TONIGHT THROUGH SUNDAY WITH SEVERAL INCHES OF LIGHT FLUFF ANTICIPATED TO ACCUMULATE. 20Z SURFACE ANALYSIS SHOWS ARCTIC HIGH PRESSURE ENTRENCHED ACROSS THE CENTRAL PART OF THE COUNTRY...WITH CHILLY TEMPS AND VERY LITTLE IN THE WAY OF CLOUD COVER. BUT THIS IS EXPECTED TO CHANGE AS A TROUGH OUT ACROSS THE INTERMOUNTAIN WEST MOVES QUICKLY INTO OUR AREA BY SUNDAY AFTERNOON. WITH SUCH COLD AIR IN PLACE...AS THE RELATIVELY WARMER AND MORE MOIST AIR MOVES NORTHWARD AHEAD THE SYSTEM...SEVERAL HOURS OF LIGHT FLUFFY SNOW WILL OCCUR. SATELLITE SHOWS HIGH CLOUDS ALREADY STREAMING INTO IA AHEAD OF THE SYSTEM... WITH THICKENING CLOUDS THROUGH THE NIGHT TONIGHT. MODELS HAVE BEEN INSISTING THAT THE FIRST WAA/ISENTROPIC UPGLIDE SNOW WILL BEGIN ACROSS WESTERN IA AND SOUTHERN MN BY 12Z...BUT IT WILL BE FIGHTING VERY DRY AIR INITIALLY. MODEL SOUNDINGS SHOW THE DOWNWARD SATURATION WITH TIME. FEEL LIGHT ACCUMULATION WILL BE POSSIBLE OVER SOUTHEAST MN AND NORTH CENTRAL IA ALREADY BEFORE SUNRISE...WITH SNOW QUICKLY OVERSPREADING THE REMAINDER OF THE AREA DURING THE MORNING. DRY AIR WILL BE THE MOST STUBBORN OVER SOUTHERN WI WITH THE EASTERLY FLOW AROUND THE DEPARTING SURFACE HIGH. WITH THIS SCENARIO AND IN AN EFFORT TO COORDINATE WITH SURROUNDING OFFICES...HAVE STAGGERED THE START TIMES OF THE WINTER WEATHER ADVISORY. SNOW RATIO SHOULD BE IN THE 17:1 TO 20:1 RANGE...SO IT WILL NOT TAKE MUCH LIQUID TO GENERATE A GOOD DEAL OF SNOW. SNOW SHOULD BE TAPERING OFF FROM WEST TO EAST SUNDAY NIGHT. PROBABLY COULD END THE ADVISORY EARLIER THAN 12Z MONDAY OVER MN/IA...BUT KEPT IT GOING FOR SIMPLICITY. ONE OTHER CONCERN IS THE WESTERLY WINDS THAT WILL KICK IN BEHIND THE SYSTEM. WITH THE LIGHT FLUFFY NATURE OF THE NEW SNOW...IT WILL PROBABLY BE MOVED AROUND WITH THE WIND. DO NOT FEEL IT WILL BE TRUE BLOWING SNOW HOWEVER... BUT RATHER JUST SOME DRIFTING IN OPEN AREAS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 206 PM CST SAT DEC 7 2013 HIGH PRESSURE BUILDS IN AGAIN ON MONDAY...BUT THE AREA WILL REMAIN UNDER NORTHWEST FLOW ALOFT. SEVERAL PASSING WEAK SHORT WAVE TROUGHS IN THE FLOW MAY RESULT IN SOME LIGHT SNOW OR FLURRIES FROM TIME TO TIME. ONE SUCH DISTURBANCE COMES THROUGH MONDAY NIGHT INTO TUESDAY ACROSS NORTHERN WI...AND ANOTHER COMES THROUGH TUESDAY NIGHT...AND YET ANOTHER THURSDAY AND FRIDAY. IT WILL REMAIN QUITE CHILLY THROUGH THE COMING WEEK AS WELL...WITH TEMPERATURES REMAINING WELL BELOW NORMAL ALL THROUGH THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 132 AM CST SUN DEC 8 2013 LIGHT SNOW IS RAPIDLY DEVELOPING AND/OR SPREADING INTO THE TAF SITES...LIKELY A CONSEQUENCE OF THE AIRMASS BEING SO COLD TO BEGIN WITH. VISIBILITIES HAVE ALREADY DROPPED TO MVFR AT RST WITH SNOW LIKELY TO BEGIN SOON AT LSE WITH FLURRIES BEING OBSERVED AT OUR OFFICE. VISIBILITIES AT BOTH TAF SITES SHOULD DROP TO IFR WITHIN A FEW HOURS AFTER THE SNOW STARTS...I.E. 09Z AT RST AND 12Z AT LSE. CEILINGS ARE ALSO LOWERING QUICKLY UPSTREAM TO THE WEST WITH MVFR CEILINGS LIKELY BY 12Z. FURTHER LOWERING IN CEILINGS AND VISIBILITIES ARE EXPECTED THIS AFTERNOON AS SNOW PICKS UP INTENSITY. THERE MAY EVEN BE A PERIOD OF LIFR VISIBILITIES DURING THE AFTERNOON/EARLY EVENING HOURS. SNOW SHOULD THEN BEGIN TAPERING OFF TOWARDS 06Z...HELPING VISIBILITIES IMPROVE. FLUFFY SNOW ACCUMULATIONS OF NEAR 3 INCHES ARE EXPECTED TODAY WITH ANOTHER INCH OR SO DURING THE EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR WIZ017-029-032>034-041. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST MONDAY FOR WIZ042>044-053>055-061. MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ079-086-087- 094-095. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR MNZ088-096. IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR IAZ008-009-018- 019. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR IAZ010-011-029-030. && $$ UPDATE...AJ SHORT TERM...MW LONG TERM....MW AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
837 AM EST Sun Dec 8 2013 ...Forecast Update... Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Will continue to monitor and upgrade if impacts begin to increase over the next hour or so. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (00Z TAF Update)... Updated at 607 AM EST Sun Dec 8 2013 Light mixed wintry precipitation will continue through the morning hours at SDF and LEX. For BWG, light freezing rain will switch to just light rain around 17z. Ceilings will lower to low end MVFR or to IFR within this precipitation For BWG, Light sleet and freezing rain will continue with IFR ceilings through the mid to late morning hours, after which, it will switch over to just light rain and diminish. Precipitation rates will stay light enough so that visibilities will stay in the upper MVFR range. Light drizzle with continued IFR ceilings are likely this afternoon. Cloudy skies and possibly light drizzle will continue overnight with IFR ceilings. For LEX, Light sleet, possibly mixed at first with light snow will be ongoing right around the TAF issuance time. Ceilings will lower to IFR by 14z and continue this way through much of the day. This will change into light freezing rain which will continue through the morning hours, eventually changing to light rain or drizzle by mid afternoon. IFR ceilings are likely this evening and overnight. For SDF, Light sleet and snow will continue through the morning hours...possibly changing to light freezing rain or freezing drizzle by early afternoon. Precipitation rates will stay light, so that ground-based visibilities will stay high in the MVFR or even VFR range today. IFR ceilings are expected this afternoon and tonight. Northeast winds of 5 to 10 mph tonight will veer to easterly by morning. Winds will become southerly at around 5 mph this evening. In general, for the overnight period and through early Monday, IFR ceilings and possibly some MVFR visibilities will continue even with a general lack of precipitation. Ceilings will rise into the MVFR category for all TAF sites by Monday afternoon as winds become westerly at 5 to 10mph after noon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 3 PM EST /2 PM CST/ this afternoon FOR KYZ061>067-070>078-081-082. WINTER WEATHER ADVISORY until 6 PM EST /5 PM CST/ this evening FOR KYZ023>043-045>049-053>057. IN...NONE. && $$ Update.........KJD Short Term.....JSD Long Term......RJS Aviation.......JSD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 AM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 635 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND SSW DIRECTION AT KSAW/KIWD WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KCMX...LAKE EFFECT SNOW WILL DIMINISH/END IN THE NEXT FEW HOURS AS BACKING WINDS PUSH LES OFFSHORE AND CONDITIONS IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. EXPECT IMPROVEMENT IN VSBY TO VFR LATE TONIGHT AT KIWD AS BACK EDGE OF PCPN/SNOW SHIELD LIFTS NORTH. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...VOSS MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
602 AM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...ROLFSON MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 526 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
854 AM CST SUN DEC 8 2013 .DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES && .PREV DISCUSSION... /ISSUED 532 AM CST SUN DEC 8 2013/ AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK. LIGHT SNOW WILL CONTINUE OVER THE TAF SITES THROUGH 20Z...WITH THE HEAVIER INTENSITIES REMAINING OVER KLNK. IFR CONDITIONS ARE EXPECTED PRIMARILY AT KLNK IN SNOW WITH MVFR TO VFR AT KOFK AND KOMA. SNOW WILL TAPER OFF AND END FROM WEST TO EAST LATER THIS AFTERNOON. TOTAL SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE POSSIBLE...WITH THE HEAVIER AMOUNTS AT KLNK AND KOMA. SKIES ARE EXPECTED TO SCATTER OUT THIS EVENING AND EVENTUALLY CLEAR OUT OVERNIGHT. A COLD FRONT WILL MOVE ACROSS THE TAF SITES BY EARLY EVENING. THIS COULD PUSH NORTHWEST WINDS UP TO AROUND 10-12KTS OVERNIGHT AND PRODUCE SOME DRIFTING OF SNOW OVERNIGHT. KERN PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>093. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
532 AM CST SUN DEC 8 2013 .AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK. LIGHT SNOW WILL CONTINUE OVER THE TAF SITES THROUGH 20Z...WITH THE HEAVIER INTENSITIES REMAINING OVER KLNK. IFR CONDITIONS ARE EXPECTED PRIMARILY AT KLNK IN SNOW WITH MVFR TO VFR AT KOFK AND KOMA. SNOW WILL TAPER OFF AND END FROM WEST TO EAST LATER THIS AFTERNOON. TOTAL SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE POSSIBLE...WITH THE HEAVIER AMOUNTS AT KLNK AND KOMA. SKIES ARE EXPECTED TO SCATTER OUT THIS EVENING AND EVENTUALLY CLEAR OUT OVERNIGHT. A COLD FRONT WILL MOVE ACROSS THE TAF SITES BY EARLY EVENING. THIS COULD PUSH NORTHWEST WINDS UP TO AROUND 10-12KTS OVERNIGHT AND PRODUCE SOME DRIFTING OF SNOW OVERNIGHT. KERN && .PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
449 AM MST SUN DEC 8 2013 .AVIATION... 12Z TAF CYCLE IFR/LIFR CIGS AND VSBYS IN BR AND FZFG CONTINUE ACROSS THE EASTERN PLAINS THIS MORNING...THOUGH THIS SHOULD CONTINUE TO ERODE FROM WEST TO EAST AS SW WINDS INCREASE THIS MORNING. WILL LIKELY HANG ON THE LONGEST AT KROW. MEANWHILE...SNOW CONTINUES ACROSS THE NORTH AND WEST...WITH THE HEAVIEST SNOW BAND OCCURRING ALONG A COLD FRONT. STRONG AND GUSTY SW TO W WINDS WILL ALSO ARRIVE WITH THE FRONT AND LAST FOR 1 TO 3 HOURS. THOUGH THE BAND OF SNOW WILL STRUGGLE TO MAKE IT EAST OF THE CENTRAL MOUNTAIN CHAIN... THE WIND WILL NOT. GUSTS NEAR 45KT WILL BE POSSIBLE...ESPECIALLY ALONG AND JUST EAST OF THE CENTRAL MTN CHAIN FROM MID MORNING THROUGH EARLY AFTN. WINDS WILL DIMINISH LATE THIS AFTERNOON. MAY SEE SOME LOW CLOUD DEVELOPMENT IN THE VCNTY OF KROW AFT 06Z TONIGHT. 34 && .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
338 AM MST SUN DEC 8 2013 ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... .DISCUSSION...MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ && .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .AVIATION... 06Z TAF CYCLE IFR AND MVFR CIGS COVERAGE HAS DECREASED IN VCNTY OF RIO GRANDE VALLEY...BUT MVFR TO LOCALLY IFR CIGS MAY REDEVELOP IN THIS AREA AFTER 10Z...MUCH MORE SO THOUGH NORTH OF INTERSTATE 40. SAF TAF SITE SHOULD SEE SIGNIFICANT IMPROVEMENT TO SCT OR AT LEAST HIGHER CIGS BETWEEN 07Z AND 10Z WITH SOME LOWERING AGAIN THEREAFTER. SOME CIG HEIGHT RISES AT LVS AND PERHAPS ROW AFTER 11Z...BUT LESS LIKELY THAN SAF TO IMPROVE TO SCT CLOUDS. OTHERWISE MOST OF THE EASTERN PLAINS LIKELY TO STAY IN PRETTY SOLID MVFR TO IFR CIGS OVERNIGHT WITH IMPROVEMENT TO SCT AFTER 15Z. CIGS AND VSBY LOWERING EXPECTED AFTER 06Z AT FMN AND GUP WITH SOME AREAS OF LIGHT TO BRIEFLY MODERATE SNOW. MT OBSCURATIONS LIKELY MOST PEAKS AND RANGES OVERNIGHT. WINDS IN THE LOWER BOUNDARY LAYER WILL LIKELY INCREASE MODESTLY OVERNIGHT WITH GREATER INCREASES HIGHER TERRAIN...BUT STRONGER WINDS LIKELY ACROSS MUCH OF THE AREA LATE MORN AND AFTN SUNDAY. 43 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 26 5 21 -1 / 30 0 5 0 DULCE........................... 23 -4 18 -16 / 40 5 5 0 CUBA............................ 27 6 21 -7 / 40 10 20 0 GALLUP.......................... 31 4 25 -8 / 30 5 20 0 EL MORRO........................ 31 1 25 -10 / 40 10 30 5 GRANTS.......................... 34 8 28 -5 / 30 5 20 0 QUEMADO......................... 38 15 29 -1 / 30 5 20 5 GLENWOOD........................ 44 22 38 12 / 10 5 20 0 CHAMA........................... 19 -8 13 -16 / 60 10 5 0 LOS ALAMOS...................... 30 9 23 -2 / 40 10 30 5 PECOS........................... 27 8 20 -1 / 30 10 30 5 CERRO/QUESTA.................... 22 -4 16 -13 / 40 10 10 0 RED RIVER....................... 17 -6 11 -16 / 60 10 20 0 ANGEL FIRE...................... 21 -10 15 -18 / 50 10 20 5 TAOS............................ 25 0 19 -14 / 30 5 10 0 MORA............................ 26 4 20 -4 / 30 5 30 5 ESPANOLA........................ 33 11 27 3 / 20 5 10 0 SANTA FE........................ 28 9 21 1 / 30 10 20 5 SANTA FE AIRPORT................ 31 12 24 2 / 20 5 20 5 ALBUQUERQUE FOOTHILLS........... 36 17 30 6 / 10 5 30 5 ALBUQUERQUE HEIGHTS............. 37 20 30 10 / 5 0 30 0 ALBUQUERQUE VALLEY.............. 39 15 32 5 / 5 0 30 0 ALBUQUERQUE WEST MESA........... 38 18 31 9 / 5 0 30 0 LOS LUNAS....................... 42 21 34 9 / 5 0 30 0 RIO RANCHO...................... 37 18 31 9 / 10 0 30 0 SOCORRO......................... 48 24 37 15 / 0 0 30 5 SANDIA PARK/CEDAR CREST......... 33 10 26 -3 / 30 10 40 5 TIJERAS......................... 34 12 27 -5 / 20 5 40 5 MORIARTY/ESTANCIA............... 32 -1 26 -13 / 20 5 30 10 CLINES CORNERS.................. 30 11 21 2 / 30 5 50 20 GRAN QUIVIRA.................... 37 18 29 7 / 20 0 40 20 CARRIZOZO....................... 43 24 37 16 / 10 0 40 20 RUIDOSO......................... 38 21 32 16 / 10 0 50 30 CAPULIN......................... 28 3 16 2 / 10 5 10 5 RATON........................... 29 2 20 -2 / 20 5 10 5 SPRINGER........................ 31 4 21 -3 / 10 5 10 5 LAS VEGAS....................... 29 8 20 -1 / 20 5 20 10 CLAYTON......................... 33 6 18 7 / 5 5 10 10 ROY............................. 33 7 19 3 / 5 5 20 10 CONCHAS......................... 41 12 25 6 / 5 0 30 10 SANTA ROSA...................... 41 15 26 10 / 5 0 30 20 TUCUMCARI....................... 45 12 28 10 / 0 5 20 20 CLOVIS.......................... 44 15 26 14 / 0 5 20 20 PORTALES........................ 44 16 27 13 / 0 0 20 20 FORT SUMNER..................... 43 18 29 13 / 0 5 20 20 ROSWELL......................... 49 25 36 19 / 0 0 10 30 PICACHO......................... 47 24 34 17 / 0 0 30 30 ELK............................. 46 24 34 18 / 0 0 40 30 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$ 41
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 AM EST SUN DEC 8 2013 .SYNOPSIS... CHILLY AND DAMP CONDITIONS WILL PREVAIL TODAY BEFORE A WARM FRONT BRINGS A SHORT-LIVED WARM-UP ON MONDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...BRINGING A REINFORCEMENT OF COOLER AIR THROUGH MID WEEK. ANOTHER STORM SYSTEM MAY BRING RAIN TO THE REGION NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY...PERSISTENCE EMPLOYED FOR THE NEAR TERM UPDATE AS THE METEOROLOGICAL SET-UP SUPPORTS A COOL AND WET REGIME TO PREVAIL ALL DAY AND OVERNIGHT. NEAR TERM MODEL DATA HOWEVER POINTS TO ATYPICAL TEMPERATURE CURVES TONIGHT...WITH A SLOW CLIMB FROM THE MIDDLE AND UPPER 40S TO AROUND 50 DEGREES BY DAYBREAK MONDAY AS SW FLOW ALOFT STRENGTHENS AND SCOURS THE SHALLOW AND COOL WEDGE OF MARITIME INFLUENCE. HOW QUICKLY THIS OCCURS REMAINS UP FOR ASSESSMENT...BUT IT APPEARS THE WEDGE WILL REMAIN ENTRENCHED OVER THE FORECAST AREA THROUGH DAYBREAK MONDAY. THIS MAKE TEMP AND WIND FORECASTS A BIT MORE PREDICTABLE THAN THE TRANSITION OF WARMING ON MONDAY MORNING. MAXIMUM TEMPERATURES AS A RESULT WILL LIKELY OCCUR FOR TODAYS 24 HOUR CALENDER PERIOD JUST PRIOR TO 12Z/7AM MONDAY MORNING. PRECIPITATION-WISE THE OVER-RUNNING WEDGE PATTERN WILL SUPPORT OCCASIONAL DRIZZLE AREA-WIDE THROUGH TONIGHT. IN FACT AS THE WARM FRONTAL TYPE PROCESS GEARS UP EARLY ON MONDAY...AREAS OF DENSE FOG AND DRIZZLE MAY EXPAND OVER THE FORECAST AREA TO START THE WEEK. P-TYPE ANALYSIS SHOWS THAT BOTH STRATIFORM AND CONVECTIVE TYPE RAINFALL WILL PREVAIL OVER THE AREA THROUGH TONIGHT...BUT NOT A LARGE OR SIGNIFICANT CONTRIBUTION FROM EITHER. WILL CONTINUE TO ADVERTISE SCATTERED TO LIKELY POP VALUES TO HIGHLIGHT DECENT PROBABILITIES OF MEASURABLE PRECIPITATION HOWEVER ACCOMPANIED BY INTERMITTENT DRIZZLE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...SHARP CLASSIC COLD AIR DAMMING EVENT WILL COME TO AN END EARLY IN THE PERIOD WITH THE FORECAST DILEMMA BEING FORECAST HIGHS FOR MONDAY. THE MET CONTINUES TO ADVERTISE THE COOLER NUMBERS AND WITH LINGERING LOW LEVEL MOISTURE AND NEARING THE WINTER SOLSTICE...THESE SEEM MORE REASONABLE ALTHOUGH WITH ANY APPRECIABLE CLOUD OR EARLY BREAKS...VERY WARM TEMPERATURES IN THE 850-900MB LAYER COULD MIX DOWN. THE FORECAST SOLUTIONS REGARDING THE FRONT TUESDAY CONTINUE TO WAVER AND SLOW THE PROGRESSION OF THE FRONT. IN FACT...THE GFS SHOWS A SECONDARY AREA OF QPF DEVELOPING WITH THE SOUTHWEST FLOW WEDNESDAY THUS SLOWING THE FRONT FOR TUESDAY. THIS IS THE FIRST CYCLE THIS HAS APPEARED SO I DID MAINTAIN THE LIKELY POPS FOR TUESDAY AND INCREASED THE LONGEVITY OF THE MOISTURE FOR TUESDAY EVENING. NO CHANGES TO TEMPERATURE FORECAST FOR TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...CONFIDENCE HAS WALKED BACK SLIGHTLY WITH REGARDS TO THE EVENTS FOR THE EXTENDED FORECAST. THE NEW AND WETTER SOLUTION AS ADVERTISED BY THE GFS OPERATIONAL PUTS WEDNESDAY IN QUESTION ALTHOUGH I DID NOT CHANGE THE DRY FORECAST AT LEAST FOR NOW TO SEE IF MORE SOLUTIONS COME IN SIMILAR. THE GFS ALSO CONTINUES TO SHOW A FAIRLY STRONG SOUTHERN STREAM SYSTEM FOR THE END OF THE WEEK INSTEAD OF THE WEAKLY FORCED COASTAL TROUGH. I HAVE ALONG WITH ADJACENT OFFICES INCREASED POPS AND CLOUD COVER FOR THE END OF THE PERIOD. NO CHANGES TO THE TEMPERATURE FORECAST ALTHOUGH ONCE AGAIN THE READINGS MAY SEE SOME CHANGES DEPENDING ON THE MASS FIELDS. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... AS OF 15Z...PREDOMINATELY IFR CONDITIONS THIS MORNING WITH STRATUS AND OCCASIONAL LIGHT DRIZZLE. THERE IS A BATCH OF HEAVIER SHOWERS NOW MOVING THROUGH THE NORTHERN THIRD OF THE CWA...ASSOCIATED WITH A WEAK DISTURBANCE. EXPECT THIS AREA OF SHOWERS TO MOVE NORTHEAST AND OUT OF THE REGION BY 13Z. THE WEDGE WILL PROBABLY STAY IN PLACE THROUGH THE FORECAST PERIOD...PERHAPS LIFTING ALONG THE COAST BY 10-11Z ON MONDAY. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE EXTENDED PERIOD WITH LIFR/IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY FRONT THROUGH MONDAY. SHOWERS LIKELY TUESDAY FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE. && .MARINE... NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1025 AM SUNDAY...THE SCA HAS BEEN EXTENDED TO MID- AFTERNOON TODAY FOR ALL WATERS. THE NE WINDS CONTINUE TO HOWL AT 15 TO 25 KT WITH GUSTS APPROACHING 30 KT OFF CAPE FEAR EARLY THIS MORNING. WITH A SLIGHTLY SLOWER BREAKDOWN IN THE WEDGE BEING FORECAST DURING THIS PERIOD...HAVE SLOWED THE DIMINISHING TREND OF THE NE WINDS ACROSS THE LOCAL WATERS TODAY THROUGH TONIGHT. THIS IS DEPICTED WELL BY THE HOURLY HRRR MODEL RUNS ILLUSTRATING PROGGED SFC WINDS. THIS WILL ALSO PRODUCE A SLOWER SUBSIDING TREND TO THE SIGNIFICANT SEAS FROM ROUGHLY 4 TO 7 FT EARLY THIS AM...TO 2 TO 5 FT BY SUNDAY EVENING. THE MAKE-UP OF THE SIGNIFICANT SEAS WILL REMAIN FROM THE LOCALLY PRODUCED WIND DRIVEN VARIETY...WITH AVERAGE PERIODS AROUND 5 SECONDS. SEA FOG MAY BECOME AN ISSUE ONCE AGAIN DURING THE PRE-DAWN MONDAY HRS BUT LIKELY HOLD OFF INTO THE NEXT PERIOD WHEN S-SW WINDS ACROSS LOCAL SSTS IN THE 50S OCCUR. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...LIGHT AND ESSENTIALLY VARIABLE WINDS WILL QUICKLY FIND DEFINITION AS A SOUTHWEST FLOW OF 15-20 KNOTS DEVELOPS MIDDAY MONDAY. THIS FLOW WILL CONTINUE THROUGH MOST OF THE DAY TUESDAY BEFORE A LONG ADVERTISED FRONT MOVES ACROSS THE WATERS. BY 0600 UTC WEDNESDAY WINDS WILL BE NORTH ACROSS ALL WATERS WITH THE SAME 15-20 KNOTS. THE CHANGE IN FETCH AND THE FACT WINDS SEEM TO REMAIN CAPPED AT 20 KNOTS SHOULD KEEP SEAS BELOW FLAG CRITERIA IN A 2-4 FOOT RANGE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...A NORTH TO NORTHEASTERLY FLOW WILL GREET MARINERS INITIALLY WITH A FEW HOURS OF 15-20 KNOTS DIMINISHING SLIGHTLY TO 10-15 KNOTS BY WEDNESDAY EVENING. SLOW MOVING HIGH PRESSURE AND LOW PRESSURE WELL OFFSHORE WILL KEEP THIS FLOW IN PLACE THROUGH THURSDAY. SEAS SHOULD REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. && $$ NEAR TERM...DOUG/MJC SHORT TERM...SHK LONG TERM...SHK AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
956 AM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE TRAVELING UP THE APPALACHIANS WILL BRING A MIXTURE OF WINTRY PRECIPITATION TODAY INTO TONIGHT. HIGH PRESSURE WILL TRY TO BUILD IN ON MONDAY...BUT ANOTHER WEAK SYSTEM WILL AFFECT THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DECENT ISENTROPIC LIFT COMBINING WITH UPR LEVEL DIVERGENCE FROM THE RR QUAD ENTRANCE REGION OF UPR LEVEL JET WILL PRODUCE WIDESPREAD PCPN ACRS THE REGION THIS MORNING INTO THE FIRST PART OF THIS AFTERNOON. WAA WILL GRADUALLY WARM ATMOSPHERIC COLUMN ALOFT FROM SE TO NW THROUGH THE DAY. AS THIS OCCURS...SNOW WILL TRANSITION TO A MIXTURE OF SLEET AND FREEZING RAIN. IT SHOULD WARM UP ENOUGH IN THE FAR SE LATE THIS AFTERNOON FOR LIQUID PCPN. UPDATE THIS MORNING WAS TO BUMP UP SNOWFALL AMOUNTS A BIT IN THE SE CWFA AS SOME BURSTS OF MODERATE SNOW HAS ALREADY RESULTED IN ACCUMS AROUND AN INCH. SO...2 TO 3 LOOKS GOOD HERE WITH 1 TO 2 FARTHER NORTH IN DAYTON AND COLUMBUS METROS AND LESS THAN AN INCH NORTHWEST. LATEST MODEL SINDICATE THAT WE COULD END UP WITH LIGHTER PCPN THIS EVENING/OVERNIGHT OVER MUCH OF THE REGION DUE TO DEEP MOISTURE EXITING AND FORCING REMAINING FOCUSED NEAR THE SE WITH A LOW LEVEL JET. WITH WARM TEMPS ALOFT AND SFC TEMPS NEAR OR SLIGHTLY BELOW FREEZING WILL RESULT IN EITHER LIGHT FREEZING RAIN OR FREEZING DRIZZLE. HEADLINES WILL HAVE TO BE ADJUSTED AT SOME POINT. TOSSED AROUND ADDING OUR NW CWFA IN AN ADVISORY...BUT WILL WAIT FOR SOME NEWER MODEL RUNS TO SEE IF PCPN WILL BE ENOUGH TO DO SO. TEMPS STARTING OUT COLD WITH ANY LIGHT LIQUID PCPN WITH SFC TEMPS BELOW FREEZING COULD CAUSE SOME ISSUES ON UNTREATED SIDEWALKS AND ROADS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE DEEP MOISTURE BEGINS TO BE SHUNTED E AT THE BEGINNING OF THE PERIOD...LEAVING THE W WITH VERY SHALLOW MOISTURE AND WEAKENING LIFT. THIS IS A SETUP FOR MORE OF A FZDZ/FZRA SCENARIO AS COMPARED TO SN/PL. THEREFORE BEGAN TO LOWER THE POPS IN THE W AND INTRODUCED MORE OF THE FZDZ/FZRA. EXPECT MUCH OF THE AREA TO MAKE THE CHANGE OVER AS TONIGHT PROGRESSES. THE EXCEPTION WILL BE THE SE/E WHERE TEMPERATURES MIGHT STAY UP ALL NIGHT THEREFORE STAYING ALL RAIN. THE ADVISORY IN THOSE LOCATIONS MIGHT BE TOO LONG...BUT WILL NOT CHANGE THE TIMING RIGHT NOW. INSTEAD WILL LET LATER SHIFTS CANCEL IT IF IT IS NOT NEEDED. LOWS TONIGHT SHOULD STAY UP IN THE LOWER TO MID 30S IN THE SE...BUT WILL FALL INTO THE UPPER 20S BACK TO THE W AS THE COOLER AIR WORKS IN ON THE BACKSIDE OF THE SYSTEM AS THE SYSTEM SLIDES E EARLY MONDAY...THE REGION WILL BE STUCK UNDER A SUBSIDENCE INVERSION...WHICH SHOULD KEEP LOW CLOUDS IN THROUGHOUT THE DAY. RIGHT NOW ENDED THE DZ/FZDZ MONDAY MORNING...BUT WITH THE LOW CLOUDS THE LIGHT PCPN COULD LINGER. MONDAY NIGHT INTO TUESDAY SEES A SPLIT LEVEL FLOW DEVELOP WITH A NRN STREAM VORT PIVOTING INTO THRU THE OHIO VALLEY LATE MONDAY NIGHT INTO TUESDAY. MODELS PRODUCE AN RIBBON OF SNOW ALONG THE LEADING EDGE OF THE ARCTIC AIR...WITH THE NAM THE QUICKEST AS IT PUSHES THE SNOW IN MONDAY NIGHT. THE GFS AND ECMWF WAIT UNTIL TUESDAY TO BRING THIS FEATURE IN. WILL LEAN TOWARD THE GFS/ECMWF SOLUTION AND WILL KEEP A MENTION OF SNOW ACRS SE HALF OF FA TUESDAY. HIGHS MONDAY AND TUESDAY WILL REMAIN MUCH BELOW NORMAL. ON MONDAY THEY WILL BE IN THE UPPER 20S IN THE NW TO THE MID 30S IN THE SE. THEN ON TUESDAY WITH THE WEATHER SYSTEM WORKING THROUGH HIGHS WILL ONLY REACH THE LOWE 20S IN THE N AND THE LOWER 30S IN THE S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY WEDNESDAY WITH WEAK SYSTEM DROPPING THRU THE GREAT LAKES. THE FAVORABLE MSTR/LIFT TO STAY TO OUR NORTH...SO HAVE MAINTAINED A DRY FCST WED. COLD TEMPERATURES TO PERSIST WITH LOWS AROUND 10 DEGREES WEST TO 15 DEGREES SE AND HIGHS LOWER/MIDDLE 20S NW TO THE LOWER 30S SE. SFC HIGH PRESSURE TO BUILD ACRS THE REGION THURSDAY/FRIDAY TIME FRAME. COLD TEMPERATURES TO CONTINUE THURSDAY WITH MORNING LOWS FROM SINGLE DIGITS OVER THE WEST WHERE SNOW COVER EXISTS TO NEAR 15 SE. HIGHS TO RANGE FROM THE LOWER 20S NW TO NEAR 30 SE. SOME MODERATION TO TEMPERATURES EXPECTED FRIDAY ON BACK SIDE OF SFC HIGH PRESSURE WITH HIGHS FROM LOWER 30S NW TO THE UPPER 30S SE. MID LEVEL FLOW BACKS WITH SYSTEM EXPECTED TO DEVELOP ALONG THE EASTERN SEABOARD LATE FRIDAY INTO SATURDAY. ILN FA IS ON THE FAR NW FRINGE OF THIS SYSTEM AND HAVE LIMITED ANY MENTION OF PRECIP TO A SLIGHT CHC OF A SNOW SHOWER IN THE FAR SE LATE FRIDAY NIGHT INTO SATURDAY. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... CIGS WILL CONTINUE TO LOWER THIS MORNING AS MOISTURE OVERSPREADS THE ESTABLISHED COLD AIR DOME IN PLACE OVER THE OHIO VALLEY. CIGS WILL DROP TO THE MVFR CATEGORY IN A RAPID FASHION THIS MORNING AND LOWER TO IFR IN THE AFTERNOON. WHILE THE PLUME OF THE BEST MOISTURE WILL REMAIN SOUTHEAST OF THE I-71 CORRIDOR AND MAJORITY OF TAF SITES...A PROLONGED PERIOD OF LIGHT PRECIPITATION WILL OCCUR AND CIGS AT THE END OF THE VALID TAF ARE EXPECTED TO DIP TO THE LIFR OR VLIFR. AS FAR AS PTYPE GOES...SNOW WILL OCCUR IN THE MORNING AND TRANSITION TO A FREEZING RAIN MIXED IN WITH SLEET BY THE AFTERNOON. SOUNDINGS IN THE LATER AFTERNOON APPEAR TO HAVE THE TOP OF THE MOISTURE COLUMN STUCK BETWEEN 0 AND -5 DEGREES AND LACKING ANY DENDRITIC GROWTH...SUPPORTING SUB FREEZING RAINDROPS AND DRIZZLE WHICH WILL FREEZE ON SURFACES. TEMPERATURES MAY RISE TO ABOVE FREEZING IN THE LATE AFTERNOON AND MORESO OVERNIGHT BUT STILL LINGER AROUND THE FREEZING MARK AND ADD TO THE POSSIBILITY OF A PTYPE ISSUE. PRECIP THROUGH THE MAJORITY OF THE NEXT 24 HOURS WILL BE LIGHT BUT CIGS ARE EXPECTED TO DROP SIGNIFICANTLY GIVEN THE DEEP MOISTURE OVER THE REGION. WHILE A CHANGEOVER TO -SN IS EXPECTED BEFORE THE PRECIP ENTIRELY ENDS TONIGHT...VSBYS WILL REMAIN REDUCED BY MIST. DID NOT WANT TO KEEP AN IFR VSBY IN SNOW WHEN THE MAIN FACTOR REDUCING THE VSBY WAS THE MIST AND NOT PRECIP...EVEN IF SOME VERY LIGHT FLURRIES ARE POSSIBLE THROUGH DAYBREAK. VERY LITTLE CHANGE TO THE FORECAST AND MINUTE TIMING VARIABILITY IS FOUND AT ALL OF THE TAF FCSTS THIS MORNING. OUTLOOK...LIFR CIGS AND IFR VSBYS ARE LIKELY THROUGH MONDAY MORNING...WITH MVFR CONDITIONS CONTINUING THROUGH MONDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR OHZ045-046- 051>056-060>065-070>074-077>082-088. KY...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HICKMAN/SITES SHORT TERM...SITES LONG TERM...AR AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
420 PM EST SUN DEC 8 2013 .SYNOPSIS... COLD AND HIGH PRESSURE GRADUALLY LIFTS NORTH AND EAST AS LOW PRESSURE LIFTS NORTH FROM THE CAROLINAS TONIGHT...ACROSS SOUTHERN NEW ENGLAND DURING THE DAY MONDAY. MAINLY DRY...BUT UNSEASONABLY COLD AND BLUSTERY WEATHER IS EXPECTED FOR THE REST OF THE UPCOMING WORK WEEK. WE WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A PERIOD OF LIGHT SNOW ON TUESDAY...MAINLY SOUTH OF THE MASSACHUSETTS TURNPIKE. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... COLD AND DRY HIGH PRESSURE REMAINS RELATIVELY IN CONTROL. PER THE LATEST SURFACE ANALYSIS...THE COLD-AIR DAMMING SIGNATURE IS WELL- EVIDENT THROUGH THE MID-ATLANTIC ALONG THE EASTERN SPINE OF THE APPALACHIAN MOUNTAINS. IT WILL LIKELY TAKE SOME TIME INTO THIS EVENING FOR THE LOW PRESSURE CENTER EVOLVING OFF THE CAROLINA COASTLINE TO BEGIN THE PROCESS OF WARM AIR NORTH AND ERODING THE COLDER AIR IN PLACE. FOLLOWING HRRR TRENDS...EXPECT THE HEAVIEST BANDING OF PRECIPITATION TO REMAIN SOUTH OF THE REGION COLLOCATED WITH THE H85 THERMAL GRADIENT AND REGION OF GREATEST MID-LEVEL CONVERGENCE. WILL KEEP WITH A DRY FORECAST INTO SUNDOWN. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM MONDAY/... AN OPEN-WAVE TROUGH ACROSS THE GREAT LAKES REGION HAS BEGUN TO INTERACT WITH THE BROADER SUB-TROPICAL FLOW ACROSS THE EASTERN CONUS. INFLECTION ALONG THE COLLOCATED TIGHT THERMAL GRADIENT HAS SUBSEQUENTLY RESULTED IN A WEAK AREA OF LOW PRESSURE PRESENTLY OFF THE MID-ATLANTIC WHICH WILL DRIFT NORTHEASTWARD ACROSS CAPE COD BRINGING WITH IT A WINTRY MIX OF SNOW...SLEET...AND FREEZING RAIN FOR SOUTHERN NEW ENGLAND DURING THE TIMEFRAME /ESPECIALLY THE MONDAY MORNING COMMUTE/. HAVE GREATER CONFIDENCE WITH COLDER SOLUTIONS. WITH BROAD AGREEMENT AND RUN-TO-RUN CONTINUITY FROM THE ECMWF...PREFER THE MESO-NAM AND WRF-MODEL SOLUTIONS WHICH CAPTURE THE COLD-AIR DAMMING PROCESSES THROUGH THE CONNECTICUT RIVER VALLEY /SEE 1000-850 THICKNESSES/. TRENDS ARE NOTEWORTHY WITHIN THE LATEST HRRR RUNS. BUT OVERALL THERE IS STILL PLENTY OF UNCERTAINTY CONCERNING THERMAL PROFILES AND THE ACCOMPANYING TRANSITION PROCESS OF WINTRY WEATHER TO PLAIN RAIN. THAT BEING SAID...THERE IS A LOT TO CONSIDER. WITH H975 AGEOSTROPHIC FLOW OUT OF THE INTERIOR NORTH WITH A WEAK LOW TRACKING ACROSS THE CAPE...NOT EXPECTING EASTERLY ONSHORE FLOW NORTH OF THE LOW TO SCOUR OUT INTERIOR SURFACE COLD AIR EFFECTIVELY. EXPECT PREVAILING NORTHERLY COLD-AIR DRAINAGE FLOW...JAMMING UP THROUGHOUT INTERIOR VALLEYS /ESPECIALLY THE CT RIVER VALLEY/. 2M FORECASTED TEMPERATURES TAKEN MAINLY FROM MESO-NAM/WRF-MODEL SOLUTIONS. THOUGH THE EASTERLY ONSHORE FLOW WILL RESULT IN A FASTER TRANSITION OF PRECIPITATION TYPES ACROSS EAST COASTAL PLAIN IN THE MORNING...EXPECTING A WINTRY MIX TO LAST LONGER ACROSS THE INTERIOR INTO THE MIDDAY AND POSSIBLY THE AFTERNOON HOURS. UPSTREAM TRENDS ACROSS INTERIOR MID-ATLANTIC SHOW THIS PROCESS ALREADY ONGOING WHICH ADD FURTHER CONFIDENCE THAT COLD-AIR DAMMING OVER THE INTERIOR WILL BE A BIG ISSUE AS TO WINTER WEATHER OUTCOMES. PRECIPITATION AND SNOW/ICE AMOUNTS REMAIN A CHALLENGE...AND LIKELY THERE ARE ALWAYS SURPRISES IN STORE WITH SYSTEMS SUCH AS THESE. CONSIDERING THE AFOREMENTIONED SPATIAL AND TEMPORAL CHALLEGES IN THE PRECIPITATION TRANSITION...IMPACTING ACCUMULATIONS AT THE SURFACE... ANOTHER POINT OF CONCERN IS UPON PRECIPITATION AMOUNTS. EVALUATING THE ATMOSPHERE...FORCING IS MAINLY WITHIN LOW-LEVELS WITH LITTLE INDICATION OF DEEP-LAYER ASCENT ALBEIT SOME BROAD-SCALE DIFFLUENCE ALOFT. YET SREF V-WIND ANOMALIES AT H85 ARE +2 STANDARD-DEVIATIONS AND NOTING UPSTREAM TRENDS OVER THE MID-ATLANTIC...THERE IS THE DISTINCT POSSIBILITY FOR A MESO-SCALE BAND OF SNOW ACROSS SOUTHERN NEW ENGLAND COLLOCATED WITH THE TIGHT H85 THERMAL GRADIENT WHERE STRONG LOW-LEVEL CONVERGENCE IS MODELED TO LIFT THROUGH BETTER SNOW- GROWTH REGIONS. THERE IS SOME SIGNAL WITHIN NEAR-TERM MESOSCALE SOLUTIONS...ALBEIT CHAOTIC. IT IS ENTIRELY PLAUSIBLE TO SEE AREAS IN PROXIMITY TO THE SOUTH-COAST OF SEEING A COUPLE OF INCHES OF SNOW IN A SHORT PERIOD OF TIME DURING THE EARLY ONSET BEFORE TRANSITIONING TO RAIN. AS SUCH...WILL TAKE 1-2 INCH ACCUMULATIONS DOWN TO THE SOUTH-COAST. WILL HAVE 2-4 INCHES FOR PORTIONS OF NORTH AND WEST MA AND SOUTHERN NH. ICE ACCUMULATIONS UP TO A TENTH OF AN INCH EXPECTED ALONG AND EAST OF THE EASTERN COASTAL PLAIN...EAST OF THE I-95/I-495 BELTWAY. TOTAL LIQUID PRECIPITATION AMOUNTS AROUND 0.4 INCHES WITH THE HEAVIEST AMOUNTS JUST OFF THE SOUTH-COAST. EXPECT ACCUMULATIONS TO BEGIN THIS EVENING AND CONTINUE THROUGH THE MORNING COMMUTE. WILL SEE A GRADUAL TRANSITION OF FROZEN P-TYPES BACK INTO THE INTERIOR BEGINNING AROUND 6-8 AM...WITH LOCATIONS ACROSS WESTERN AND NORTHERN MA AND SOUTHERN NH SEEING THE LONGEST PERIOD OF A WINTRY MIX....EAST-COAST TRANSITIONING QUICKEST. HAVE LENGTHENED THE WINTER- WEATHER ADVISORY FOR HARTFORD COUNTY CT WITH THE EXPECTATION OF COLD-AIR DRAINAGE PROCESSES. IMPACTS IN THE WINTER WEATHER ADVISORY...BUT IN BREVITY...EXPECT A MESSY MONDAY MORNING COMMUTE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * PERIOD OF LIGHT SNOW POSSIBLE SOUTH OF MA PIKE ON TUE * MAINLY DRY AND UNSEASONABLY COLD WED THROUGH FRI * LOW CONFIDENCE FORECAST NEXT WEEKEND DETAILS... MONDAY NIGHT... OTHER THAN PERHAPS A LEFT OVER SPOT SHOWER IN THE EARLY EVENING... DRY WEATHER EXPECTED. A COLD FRONT SWINGS THROUGH THE REGION EARLY IN THE EVENING. TEMPS WILL ACTUALLY RISE ABOVE FREEZING ACROSS PORTIONS OF THE INTERIOR THAT HAVE BEEN JAMMED IN SHALLOW COLD AIR DURING THE DAY MONDAY. THE REASON FOR THIS IS THAT WARMER MID LEVEL AIR WILL BE TEMPORARILY MIXED DOWN...AS WINDS SHIFT TO THE WEST. THIS SHOULD ALLOW ANY LEFTOVER ICY CONDITIONS ON ROADWAYS TO MELT. COLDER AIR WILL FINALLY BEGIN WORKING BACK INTO THE REGION OVERNIGHT...WITH LOWS BY DAYBREAK BACK INTO THE 20S ACROSS THE INTERIOR. THE COASTAL PLAIN SHOULD ONLY SEE LOWS REACH THE LOWER TO MIDDLE 30S. TUESDAY... THE MAIN CONCERN IS THE CHANCES FOR A PERIOD OF LIGHT SNOW ON TUESDAY...MAINLY SOUTH OF THE MA TURNPIKE. A WEAK WAVE OF LOW PRESSURE WILL BE PASSING WELL TO OUR SOUTH...BUT AN APPROACHING SHORTWAVE BACKS THE UPPER LEVEL FLOW. IT PLACES US UNDERNEATH A POTENT JET STREAK WHICH RESULTS IN A PERIOD OF DECENT MID LEVEL LIFT. WILL BE FIGHTING LOW LEVEL DRY AIR SO NOT EXPECTING A LOT OF PRECIP...BUT A PERIOD OF LIGHT SNOW IS STILL POSSIBLE SOUTH OF MA TURNPIKE ESPECIALLY NEAR THE SOUTH COAST. PERHAPS ITS MILD ENOUGH FOR MIXED PRECIP AT THE ONSET ACROSS CAPE/ISLANDS...BUT SHOULD TURN OVER TO ALL LIGHT SNOW. WE MAY EVEN SEE A COATING TO PERHAPS 1 INCH IN A FEW LOCATIONS. THERE IS A LOW PROBABILITY OF A BIT MORE SNOW NEAR THE SOUTH COAST...BUT MOST GUIDANCE DOES NOT SUPPORT THAT AT THIS TIME. WEDNESDAY THROUGH FRIDAY... NORTHWEST FLOW ALOFT WILL RESULT IN UNSEASONABLY COLD WEATHER FOR SOUTHERN NEW ENGLAND. THERE ARE SOME MODEL DISCREPANCIES ON THE TIMING OF REINFORCING SHOTS OF COLD AIR...HENCE UNCERTAINTIES ON WHICH DAY WILL BE THE COLDEST. MAINLY DRY WEATHER DOMINATES OVER THIS TIME PERIOD...BUT CAN/T RULE OUT A BRIEF PASSING FLURRY/SNOW SHOWER WITH SOME MOISTURE STARVED NORTHERN STREAM ENERGY/FRONTAL PASSAGES. IT ALSO WILL BE WINDY AT TIMES...SO IT CERTAINLY WILL FEEL WINTERLIKE. SATURDAY AND SUNDAY... FORECAST CONFIDENCE IS VERY LOW OVER THIS TIME. THE ONE THING WILL HAVE TO WATCH NEXT WEEKEND IS THE TRACK A WAVE OF LOW PRESSURE TO OUR SOUTH. MOST MODELS SUGGEST THAT THE SYSTEM WILL PASS FAR ENOUGH SOUTH TO SPARE OUR REGION OF SIGNIFICANT PRECIP. HOWEVER...SOME MODELS SUGGEST THE LARGE HIGH TO OUR NORTH MAY EVENTUALLY RESULT IN ONSHORE FLOW...BRINGING THE POTENTIAL FOR SOME LIGHT WINTRY PRECIPITATION. OTHER GUIDANCE SUGGESTS SOUTHWEST FLOW ALOFT MAY RESULT IN SOME OVER RUNNING PRECIPITATION. ALL IN ALL...VERY LOW CONFIDENT FORECAST FOR NEXT WEEKEND. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 21Z UPDATE... NEAR-TERM /THROUGH MONDAY/...HIGH CONFIDENCE ON TRENDS. MODERATE CONFIDENCE ON TIMING OF PRECIPITATION TYPE SPECIFICS AND CIG/VSBY IMPACTS. CIGS LOWERING FROM LOW-END VFR TO MVFR/IFR. INITIAL ONSET OF -SN WITH IFR VSBYS...TRANSITIONING TO -PL/UP/FZRA THEN TO PLAIN RAIN BY MORNING INTO THE AFTERNOON. EXPECT QUICKEST TRANSITION ALONG EAST-COAST TERMINALS...MORE GRADUAL ACROSS THE INTERIOR WITH THE WINTRY MIX HOLDING ON LONGER OVER TERMINALS WITHIN VALLEYS. WITH -SN/PL WENT WITH IFR VSBYS...MVFR VSBYS FOR -FZRA/RA. NORTHERLY FLOW GRADUALLY VEERING EASTERLY THROUGH THE PERIOD WITH GUSTS UP TO AROUND 20 KTS ESPECIALLY ALONG THE COAST. THOUGH EXPECT IN SHELTERED VALLEYS A LIGHT NORTHERLY FLOW TO PREVAIL. CONDITIONS BEGIN TO IMPROVE INTO MONDAY NIGHT. KBOS TAF...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN TIMING OF PRECIPITATION TRANSITIONS. EXPECTING -SN TO QUICKLY TRANSITION TO -RA DURING THE MORNING WITH ONSHORE EASTERLY FLOW. KBDL TAF...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN TIMING OF PRECIPITATION TRANSITIONS. -SN WILL GRADUALLY TRANSITION TO A WINTRY MIX...BUT THAT MIX MAY HOLD LONGER WITH SHALLOW COLD AIR BELOW-FREEZING OVER THE TERMINAL. LIGHT NORTHERLY FLOW. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... MONDAY NIGHT...MODERATE TO HIGH CONFIDENCE. LEFT OVER MVFR-IFR CONDITIONS EARLY IN THE EVENING IMPROVE TO VFR BEHIND A COLD FRONT. TUESDAY...LOW CONFIDENCE. A PERIOD OF MVFR-IFR CONDITIONS POSSIBLE SOUTH OF THE MA TURNPIKE IN A ROUND OF LIGHT SNOW. OTHERWISE...VFR CONDITIONS FOR THE REST OF THE TIME. WEDNESDAY THROUGH FRIDAY...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS DOMINATE WITH GUSTY WNW WINDS AT TIMES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH MONDAY/...HIGH CONFIDENCE. NORTHERLY WINDS OVER THE WATERS WILL VEER EAST-SOUTHEASTERLY WITH TIME GUSTING 25 TO 30 KTS DURING THE DAY MONDAY AS AN AREA OF LOW PRESSURE CROSSES INTO SOUTHERN NEW ENGLAND. WITH THE LOW/S PASSAGE EXPECT WINDS TO BACK MORE SOUTHERLY. PROLONGED PERIOD OF FETCH WILL RESULT IN SEAS OF 6 TO 8 FEET ACROSS THE OUTER WATERS IMPACTING THE EAST- FACING ATLANTIC BEACHES. SMALL CRAFT ADVISORIES IN EFFECT FOR ALL LOCATIONS EXCEPT INNER BAYS. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. THE GENERAL IDEA IS THAT THE PASSAGE OF A COUPLE OF STRONG COLD FRONTS WILL RESULT IN PERSISTENT WEST TO NORTHWEST WINDS OVER THIS TIME. GIVEN THE STRONG COLD ADVECTION OVER THE WATERS...SCA WIND GUSTS ARE EXPECTED OVER MUCH OF THIS TIME PERIOD OVER THE OPEN WATERS. WE MAY EVEN SEE A BRIEF GALE FOR A TIME ON WEDNESDAY. THERE ALSO WILL BE LULLS IN THE WIND...BUT TIMING THAT THIS FAR OUT IS IMPOSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR CTZ002>004. MA...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR MAZ013-017. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY FOR MAZ002>005-008>012-014-026. NH...NONE. RI...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR RIZ001>004-006. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 1 PM EST MONDAY FOR ANZ231>234. SMALL CRAFT ADVISORY FROM 3 AM TO 6 PM EST MONDAY FOR ANZ235- 237-254>256. SMALL CRAFT ADVISORY FROM 7 AM TO 6 PM EST MONDAY FOR ANZ250. SMALL CRAFT ADVISORY FROM 7 AM TO 1 PM EST MONDAY FOR ANZ251. && $$ SYNOPSIS...FRANK/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...FRANK AVIATION...FRANK/SIPPRELL MARINE...FRANK/SIPPRELL
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
103 PM EST SUN DEC 8 2013 .SYNOPSIS... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND BY THIS EVENING. A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES REGION THROUGH TODAY AND MONDAY, DRAGGING A COLD FRONT THROUGH OUR AREA LATE MONDAY. MEANWHILE, A LOW PRESSURE SYSTEM WILL DEVELOP AND MOVE UP ALONG THE MIDDLE ATLANTIC COAST ON MONDAY. A SECONDARY FRONT WILL MOVE THROUGH THE REGION LATE TUESDAY INTO WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST ON WEDNESDAY BEFORE SHIFTING EAST OF THE AREA AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN EXTENSIVE SURFACE AND UPPER AIR ANALYSIS REVEALS RATHER ROBUST LOW-LEVEL WAA ACROSS PORTIONS OF THE MID ATLANTIC. TO THE NORTH OF THIS ZONE, A TIGHTENING AREA OF WEST TO EAST ORIENTATED FRONTOGENETIC FORCING IS OCCURRING. THIS FORCING IS SEEN IN THE RADAR DATA AS A BANDED FEATURE ACROSS NORTHERN MARYLAND TO PORTIONS OF SOUTHERN NEW JERSEY. THERE APPEARS TO BE SOME SLANTWISE INSTABILITY PLAYING A ROLE ALONG WITH SIGNIFICANT ISENTROPIC UPGLIDE COMBINING WITH THE SNOW GROWTH REGION. THIS IS PRODUCING SNOWFALL RATES OF 1-2 INCHES PER HOUR WITH SOME AREAS UNDER THE BAND REPORTING 4-4.5 INCHES OF SNOW ALREADY. THE VISIBLE SATELLITE IMAGERY HAS SHOWN SOME CONVECTIVE NATURE AT TIMES TO THE CLOUD FEATURES WITH THIS BAND. BASED ON THIS AND ALSO RADAR TRENDS, A WINTER STORM WARNING WAS ISSUED FOR THE COUNTIES BEING AFFECT BY THE BANDING. THE ADVISORY WAS EXPANDED TO THE REST OF THE AREA AS ROADWAYS WILL BECOME OR ALREADY HAVE BECOME HAZARDOUS. THE LATEST HRRR HAS THIS FEATURE PLACED RATHER WELL SO FAR AND IT CONTINUES TO SLIDE IT NORTHEASTWARD ACROSS PHILADELPHIA AND PORTIONS OF SOUTHERN NEW JERSEY. FARTHER NORTH, WEAKER FORCING SO FAR AND DRIER AIR IS PREVENTING THE SNOW FROM SHIFTING NORTHWARD. THE DRY AIR IS EXPECTED TO GRADUALLY GIVE WAY DURING THE REST OF THE AFTERNOON, ALLOWING SNOW TO BREAK OUT FARTHER TO THE NORTH. THE GRIDS WERE UPDATED TO INCREASE SNOW AMOUNTS ESPECIALLY FOR THE AREA BEING AFFECTED BY THE BANDING FEATURE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... HOWEVER, AS WAA INCREASES THRU THE NIGHT, THE PRECIP WILL BEGIN TO MIX AND EVENTUALLY CHANGE TO ALL RAIN FROM SE TO NW. THE GFS IS THE WARMEST/FASTEST MDL WITH THIS TRANSITION. THE NAM/WRF AND ECMWF ARE A BIT SLOWER BUT STILL HAVE THE CHANGEOVER REACHING THE I-95 CORRIDOR SHORTLY AFTER MIDNIGHT. FURTHER AND W, THE WINTRY PRECIP WILL HANG ON LONGER. CURRENT THINKING IS THE GFS IS TOO WARM/TOO QUICK WITH THE TRANSITION. IT IS STILL PSBL THERE COULD BE A PD OF FZRA ALG THE I-95 CORRIDOR, BUT CONFIDENCE IS LOW ON THIS OCCURRENCE SO NO HEADLINES ARE BEING ISSUED FOR NOW. IF THE GFS IS CORRECT, THEY WILL LIKELY NOT BE NEEDED. IF MORE SLEET OCCURS IN THE TRANSITION, THEY MAY NOT BE NEEDED EITHER. BY MON MRNG, ALL BUT THE FAR N AND W SHOULD BE RAIN. TEMPS WILL RISE OVERNIGHT AS THE WAA KICKS IN. THIS IS DEFINITELY A TRICKY TEMP DAY (AND NIGHT) AND A COUPLE OF DEGREES MAKES A WORLD OF DIFFERENCE! && .LONG TERM /MONDAY THROUGH SATURDAY/... THINGS SHOULD BEGIN TO WIND DOWN BY MONDAY MORNING WITH JUST A FEW ISSUES LEFT LINGERING ACROSS THE POCONOS IN TERMS OF ICING, THOUGH WE MIGHT BE A COUPLE HOURS TOO LONG ON THIS. OTHERWISE RAIN WILL CONTINUE TO OVERSPREAD FROM THE SOUTH-SOUTHWEST AS THE COASTAL WAVE CONTINUES ITS NORTHWARD PROGRESS PASSING JUST OFF THE DELMARVA COAST. A WEAK COLD FRONT WILL THEN PUSH IN FROM THE WEST AND EFFECTIVELY PUT AN END TO PRECIPITATION BUT IN DOING SO COLDER AIR BEGINS TO FILTER BACK INTO THE REGION. MODELS CONTINUE TO SHOW A DISCONTINUITY WITH EACH OTHER IN TERMS OF THE FINAL WAVE ON TUESDAY...DOES IT SKIRT BY TO OUR SOUTH OR HAVE ENOUGH LATITUDE TO BRUSH BY OVERHEAD. UPPER LEVEL SUPPORT IN TERMS OF THE RIGHT ENTRANCE TO THE STRONG JET AND WEAK Q-VEC CONVERGENCE COUPLED WITH WEAK FGEN IN THE 700-500MB LAYER, SHOULD ALLOW FOR SOME MORE MOISTURE TO BE SQUEEZED OUT ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA TUESDAY AFTERNOON. THERMAL PROFILES WILL BE CONDUCIVE FOR ALL SNOW TO FALL THOUGH THE ONE MAJOR QUESTION BECOMES HOW MUCH ENERGY IS STILL LEFT IN THE MID-LEVELS. BY TUESDAY THE MID-LEVEL ENERGY BECOMES VERY STRUNG OUT AND MAY HAVE GIVEN ALL IT CAN SO ONLY TIME WILL TELL IN THE AFTERMATH OF TONIGHTS SYSTEM TO SEE IF IF CAN RECOVER. SPEAKING OF SNOWFALL, NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION THOUGH SOME OF THE MODELS ARE TRYING TO SHOW A QUICK BURST TUESDAY AFTERNOON WITH DECENT DENDRITIC GROWTH POSSIBLE WITH UPWARDS OF AN INCH IN SPOTS...MOST SOUTH AND EAST OF PHILLY. WITH THE FINAL WAVE GONE, HIGH PRESSURE WORKS BACK IN ON WEDNESDAY AND TEMPERATURES PLUMMET TO WELL BELOW SEASONAL AVERAGES...THROUGH AT LEAST THE END OF THE WORK WEEK. A SLIGHT MODERATION IS EXPECTED BY SATURDAY AS THE FLOW BEGINS TO VEER SLIGHTLY TOWARDS THE WEST-SOUTHWEST. THE NEXT POTENTIAL SYSTEM LOOKS TO SKIRT BY THE COAST SATURDAY NIGHT INTO SUNDAY THROWING SOME MOISTURE BACK ACROSS THE REGION. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...A BAND OF HEAVY SNOW WILL IMPACT KILG TO KPHL AND KPNE ESPECIALLY FOR AWHILE. THIS WILL PRODUCE MVFR TO IFR CONDITIONS WITH SNOWFALL RATES AROUND AN INCH PER HOUR. THIS BAND SHOULD TRANSLATE TO THE NORTHEAST THROUGH THE AFTERNOON WITH PERHAPS SOME LESSENING OF THE SNOW INTENSITY POSSIBLE LATER. ELSEWHERE, SNOW IS EXPECTED TO ARRIVE NORTHWARD WITH THE ARRIVAL LAST AT KABE AND KTTN. THE SNOW MAY START TO MIX WITH SOME SLEET NEAR KPHL ON SOUTH AND EAST TOWARD EARLY EVENING. NORTH TO NORTHEAST WINDS 5-8 KNOTS. TONIGHT...A TRANSITION OF THE PRECIPITATION IS EXPECTED FROM SOUTHEAST TO NORTHWEST, WITH SNOW AND SLEET CHANGING TO FREEZING RAIN AND RAIN. KABE AND KRDG WILL HANG ONTO THE FROZEN/FREEZING PRECIPITATION THE LONGEST, WITH KMIV AND KACY HAVING ALL RAIN SOONER. MVFR AND TO EVEN IFR CONDITIONS /ESPECIALLY CEILINGS/ ARE EXPECTED. NORTHEAST WINDS GENERALLY AROUND 5 KNOTS, HOWEVER BECOMING EAST-SOUTHEAST MAINLY AT KACY OVERNIGHT. OUTLOOK... MONDAY...STILL EXPECTING AN MVFR/IFR DAY AS RAIN CONTINUES TO OVERSPREAD FROM THE SOUTH-SOUTHWEST. A COASTAL LOW PRESSURE WILL PASS BY HEADING TOWARDS NEW ENGLAND AND MAY HELP TO KEEP A PREDOMINANT EASTERLY FLOW ACROSS THE REGION THROUGH THE MORNING HOURS AND THEN AS THE LOW MOVES AWAY WE BACK TOWARDS THE WEST. RAIN SHOULD BEGIN TO COME TO AN END DURING THE EVENING HOURS. TUESDAY...ONE FINAL WAVE OF LOW PRESSURE MAY IMPACT THE REGION DURING THE DAY PROVIDING MVFR/IFR SNOW. NOT QUITE SURE HOW FAR INLAND THE PRECIPITATION WILL FALL BUT HIGHER CONFIDENCE AT THIS POINT IS FROM MIV AND ACY...MAYBE THE I-95 CORRIDOR. OTHERWISE WE WILL BE VFR. WEDNESDAY - THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND THROUGH TONIGHT. MEANWHILE, LOW PRESSURE WILL TRACK UP THE OHIO VALLEY WITH A SECONDARY WEAKER LOW DEVELOP NEAR THE MID ATLANTIC COAST. AS THIS OCCURS, THE NORTHEASTERLY WIND WILL INCREASE SOME AND THEN TURN EASTERLY TONIGHT ESPECIALLY ACROSS THE NORTHERN ZONES. BASED ON THE FORECAST SOUNDINGS FROM THE NAM/GFS AND ECMWF, WE OPTED TO ISSUE A SMALL CRAFT ADVISORY FOR OUR TWO NORTHERN ZONES STARTING THIS EVENING AND GOING THROUGH 11Z MONDAY AT THIS POINT. WE WILL REEVALUATE THIS LATER TODAY. WE ALSO EXTENDED THE ADVISORY FOR OUR CENTRAL AND SOUTHERN OCEAN ZONES UNTIL 05Z TONIGHT AFTER COLLABORATING WITH WFO AKQ. WE HELD OFF ON AN ADVISORY FOR DELAWARE BAY AS THE GREATER FLOW LOOKS TO BE ACROSS THE OCEAN. SEAS WILL BE NEAR 5 FEET THROUGH TONIGHT GIVEN THE FLOW INCREASING SOME AND TURNING MORE NORTHEAST AND EAST. OUTLOOK... MONDAY...LINGERING SMALL CRAFT ISSUES POSSIBLE AS THE COASTAL WAVE PULLS FURTHER NORTH WITH SEAS AND WINDS BEGINNING TO RELAX BY LATE IN THE DAY. TUESDAY AND WEDNESDAY...A FAIRLY TIGHT GRADIENT WILL EXIST FOR THE TUESDAY THROUGH WEDNESDAY TIME FRAME WITH WINDS PICKING UP OUT OF THE WEST OR NORTHWEST. WE COULD NEAR GALES ACROSS THE NORTH FOR A BRIEF TIME PERIOD WEDNESDAY MORNING BUT CONFIDENCE IS RATHER LOW RIGHT NOW. CONFIDENCE IS HIGH THAT A SMALL CRAFT WILL BE NEEDED FOR THAT TIME FRAME. THURSDAY...WINDS AND SEAS WILL SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR PAZ060>062. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR PAZ101- 103>106. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR PAZ054-055. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR PAZ070-071- 102. NJ...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR NJZ007-008. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR NJZ009. WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR NJZ021>023. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR NJZ001. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NJZ016>020- 027. WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NJZ010-012- 013-015. DE...WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR DEZ002- 003. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR DEZ001. MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ008. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ012- 015-019-020. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ452>455. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST MONDAY FOR ANZ450-451. && $$ SYNOPSIS...HEAVENER/MEOLA NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...HEAVENER AVIATION...GORSE/HEAVENER MARINE...GORSE/HEAVENER/MEOLA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1139 AM EST SUN DEC 8 2013 .SYNOPSIS... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND BY THIS EVENING. A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES REGION THROUGH TODAY AND MONDAY, DRAGGING A COLD FRONT THROUGH OUR AREA LATE MONDAY. MEANWHILE, A LOW PRESSURE SYSTEM WILL DEVELOP AND MOVE UP ALONG THE MIDDLE ATLANTIC COAST ON MONDAY. A SECONDARY FRONT WILL MOVE THROUGH THE REGION LATE TUESDAY INTO WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST ON WEDNESDAY BEFORE SHIFTING EAST OF THE AREA AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN EXTENSIVE SURFACE AND UPPER AIR ANALYSIS THIS MORNING REVEALS RATHER ROBUST LOW-LEVEL WAA ACROSS PORTIONS OF THE MID ATLANTIC. TO THE NORTH OF THIS ZONE, THERE APPEARS TO BE A TIGHTENING AREA OF WEST TO EAST FRONTOGENETIC FORCING. THIS FORCING IS SEEN IN THE RADAR DATA AS A BANDED FEATURE ACROSS NORTHERN MARYLAND AND IT IS NOW MOVING ACROSS NORTHERN DELAWARE AND SOUTHWESTERN NEW JERSEY. THE LATEST HRRR HAS THIS FEATURE PLACED WELL SO FAR AND IT SLIDES IT NORTHEASTWARD ACROSS PHILADELPHIA AND THEN ACROSS PORTIONS OF SOUTHERN NEW JERSEY. THERE ARE REPORTS OF MODERATE TO HEAVY SNOW OCCURRING WITH THIS BANDED FEATURE, WHICH IS RESULTING IN MUCH MORE EFFICIENT ACCUMULATIONS. AS A RESULT, WE EXPANDED THE WINTER WEATHER ADVISORY TO THE EAST ANOTHER TIER OF ZONES. IT MAY NEED TO BE EXTENDED TO THE COAST, BUT EVENTUAL WARMING ALOFT AND FROM THE OCEAN INFLUENCE SHOULD KEEP SNOW ACCUMULATIONS LOWERED TOWARD THE COAST. THIS IS OF LOWER CONFIDENCE HOWEVER. WE ALSO ADDED IN LIGHT ICING INTO THE NEW ADVISORY PORTION AS SOUNDINGS DO SHOW A POTENTIAL WINDOW OF OPPORTUNITY THIS EVENING DURING THE TRANSITION PERIOD. THE GRIDS ARE BEING UPDATED TO INCREASE SNOW AMOUNTS SOME ESPECIALLY FOR THE AREA BEING AFFECTED BY THE BANDING FEATURE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... HOWEVER, AS WAA INCREASES THRU THE NIGHT, THE PRECIP WILL BEGIN TO MIX AND EVENTUALLY CHANGE TO ALL RAIN FROM SE TO NW. THE GFS IS THE WARMEST/FASTEST MDL WITH THIS TRANSITION. THE NAM/WRF AND ECMWF ARE A BIT SLOWER BUT STILL HAVE THE CHANGEOVER REACHING THE I-95 CORRIDOR SHORTLY AFTER MIDNIGHT. FURTHER AND W, THE WINTRY PRECIP WILL HANG ON LONGER. CURRENT THINKING IS THE GFS IS TOO WARM/TOO QUICK WITH THE TRANSITION. IT IS STILL PSBL THERE COULD BE A PD OF FZRA ALG THE I-95 CORRIDOR, BUT CONFIDENCE IS LOW ON THIS OCCURRENCE SO NO HEADLINES ARE BEING ISSUED FOR NOW. IF THE GFS IS CORRECT, THEY WILL LIKELY NOT BE NEEDED. IF MORE SLEET OCCURS IN THE TRANSITION, THEY MAY NOT BE NEEDED EITHER. BY MON MRNG, ALL BUT THE FAR N AND W SHOULD BE RAIN. TEMPS WILL RISE OVERNIGHT AS THE WAA KICKS IN. THIS IS DEFINITELY A TRICKY TEMP DAY (AND NIGHT) AND A COUPLE OF DEGREES MAKES A WORLD OF DIFFERENCE! && .LONG TERM /MONDAY THROUGH SATURDAY/... THINGS SHOULD BEGIN TO WIND DOWN BY MONDAY MORNING WITH JUST A FEW ISSUES LEFT LINGERING ACROSS THE POCONOS IN TERMS OF ICING, THOUGH WE MIGHT BE A COUPLE HOURS TOO LONG ON THIS. OTHERWISE RAIN WILL CONTINUE TO OVERSPREAD FROM THE SOUTH-SOUTHWEST AS THE COASTAL WAVE CONTINUES ITS NORTHWARD PROGRESS PASSING JUST OFF THE DELMARVA COAST. A WEAK COLD FRONT WILL THEN PUSH IN FROM THE WEST AND EFFECTIVELY PUT AN END TO PRECIPITATION BUT IN DOING SO COLDER AIR BEGINS TO FILTER BACK INTO THE REGION. MODELS CONTINUE TO SHOW A DISCONTINUITY WITH EACH OTHER IN TERMS OF THE FINAL WAVE ON TUESDAY...DOES IT SKIRT BY TO OUR SOUTH OR HAVE ENOUGH LATITUDE TO BRUSH BY OVERHEAD. UPPER LEVEL SUPPORT IN TERMS OF THE RIGHT ENTRANCE TO THE STRONG JET AND WEAK Q-VEC CONVERGENCE COUPLED WITH WEAK FGEN IN THE 700-500MB LAYER, SHOULD ALLOW FOR SOME MORE MOISTURE TO BE SQUEEZED OUT ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA TUESDAY AFTERNOON. THERMAL PROFILES WILL BE CONDUCIVE FOR ALL SNOW TO FALL THOUGH THE ONE MAJOR QUESTION BECOMES HOW MUCH ENERGY IS STILL LEFT IN THE MID-LEVELS. BY TUESDAY THE MID-LEVEL ENERGY BECOMES VERY STRUNG OUT AND MAY HAVE GIVEN ALL IT CAN SO ONLY TIME WILL TELL IN THE AFTERMATH OF TONIGHTS SYSTEM TO SEE IF IF CAN RECOVER. SPEAKING OF SNOWFALL, NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION THOUGH SOME OF THE MODELS ARE TRYING TO SHOW A QUICK BURST TUESDAY AFTERNOON WITH DECENT DENDRITIC GROWTH POSSIBLE WITH UPWARDS OF AN INCH IN SPOTS...MOST SOUTH AND EAST OF PHILLY. WITH THE FINAL WAVE GONE, HIGH PRESSURE WORKS BACK IN ON WEDNESDAY AND TEMPERATURES PLUMMET TO WELL BELOW SEASONAL AVERAGES...THROUGH AT LEAST THE END OF THE WORK WEEK. A SLIGHT MODERATION IS EXPECTED BY SATURDAY AS THE FLOW BEGINS TO VEER SLIGHTLY TOWARDS THE WEST-SOUTHWEST. THE NEXT POTENTIAL SYSTEM LOOKS TO SKIRT BY THE COAST SATURDAY NIGHT INTO SUNDAY THROWING SOME MOISTURE BACK ACROSS THE REGION. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF TODAY...A BAND OF MODERATE TO HEAVY SNOW WILL IMPACT KILG TO KPHL ESPECIALLY FOR AWHILE. THIS WILL PRODUCE MVFR TO IFR CONDITIONS WITH SNOWFALL RATES NEARING AN INCH PER HOUR. THIS BAND SHOULD TRANSLATE TO THE NORTHEAST THROUGH THE AFTERNOON WITH PERHAPS SOME LESSENING OF THE SNOW INTENSITY POSSIBLE LATER. ELSEWHERE, SNOW IS EXPECTED TO ARRIVE NORTHWARD WITH THE ARRIVAL LAST AT KABE AND KTTN. THE SNOW MAY START TO MIX WITH SOME SLEET NEAR KPHL ON SOUTH AND EAST TOWARD EARLY EVENING. NORTH TO NORTHEAST WINDS 5-8 KNOTS. TONIGHT...A TRANSITION OF THE PRECIPITATION IS EXPECTED FROM SOUTHEAST TO NORTHWEST, WITH SNOW AND SLEET CHANGING TO FREEZING RAIN AND RAIN. KABE AND KRDG WILL HANG ONTO THE FROZEN/FREEZING PRECIPITATION THE LONGEST, WITH KMIV AND KACY HAVING ALL RAIN SOONER. MVFR AND TO EVEN IFR CONDITIONS /ESPECIALLY CEILINGS/ ARE EXPECTED. NORTHEAST WINDS GENERALLY AROUND 5 KNOTS, HOWEVER BECOMING EAST-SOUTHEAST MAINLY AT KACY OVERNIGHT. OUTLOOK... MONDAY...STILL EXPECTING AN MVFR/IFR DAY AS RAIN CONTINUES TO OVERSPREAD FROM THE SOUTH-SOUTHWEST. A COASTAL LOW PRESSURE WILL PASS BY HEADING TOWARDS NEW ENGLAND AND MAY HELP TO KEEP A PREDOMINANT EASTERLY FLOW ACROSS THE REGION THROUGH THE MORNING HOURS AND THEN AS THE LOW MOVES AWAY WE BACK TOWARDS THE WEST. RAIN SHOULD BEGIN TO COME TO AN END DURING THE EVENING HOURS. TUESDAY...ONE FINAL WAVE OF LOW PRESSURE MAY IMPACT THE REGION DURING THE DAY PROVIDING MVFR/IFR SNOW. NOT QUITE SURE HOW FAR INLAND THE PRECIPITATION WILL FALL BUT HIGHER CONFIDENCE AT THIS POINT IS FROM MIV AND ACY...MAYBE THE I-95 CORRIDOR. OTHERWISE WE WILL BE VFR. WEDNESDAY - THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND THROUGH TONIGHT. MEANWHILE, LOW PRESSURE WILL TRACK UP THE OHIO VALLEY WITH A SECONDARY WEAKER LOW DEVELOP NEAR THE MID ATLANTIC COAST. AS THIS OCCURS, THE NORTHEASTERLY WIND WILL INCREASE SOME AND THEN TURN EASTERLY TONIGHT ESPECIALLY ACROSS THE NORTHERN ZONES. BASED ON THE FORECAST SOUNDINGS FROM THE NAM/GFS AND ECMWF, WE OPTED TO ISSUE A SMALL CRAFT ADVISORY FOR OUR TWO NORTHERN ZONES STARTING THIS EVENING AND GOING THROUGH 11Z MONDAY AT THIS POINT. WE WILL REEVALUATE THIS LATER TODAY. WE ALSO EXTENDED THE ADVISORY FOR OUR CENTRAL AND SOUTHERN OCEAN ZONES UNTIL 05Z TONIGHT AFTER COLLABORATING WITH WFO AKQ. WE HELD OFF ON AN ADVISORY FOR DELAWARE BAY AS THE GREATER FLOW LOOKS TO BE ACROSS THE OCEAN. SEAS WILL BE NEAR 5 FEET THROUGH TONIGHT GIVEN THE FLOW INCREASING SOME AND TURNING MORE NORTHEAST AND EAST. OUTLOOK... MONDAY...LINGERING SMALL CRAFT ISSUES POSSIBLE AS THE COASTAL WAVE PULLS FURTHER NORTH WITH SEAS AND WINDS BEGINNING TO RELAX BY LATE IN THE DAY. TUESDAY AND WEDNESDAY...A FAIRLY TIGHT GRADIENT WILL EXIST FOR THE TUESDAY THROUGH WEDNESDAY TIME FRAME WITH WINDS PICKING UP OUT OF THE WEST OR NORTHWEST. WE COULD NEAR GALES ACROSS THE NORTH FOR A BRIEF TIME PERIOD WEDNESDAY MORNING BUT CONFIDENCE IS RATHER LOW RIGHT NOW. CONFIDENCE IS HIGH THAT A SMALL CRAFT WILL BE NEEDED FOR THAT TIME FRAME. THURSDAY...WINDS AND SEAS WILL SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR PAZ060>062. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR PAZ101>106. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR PAZ054-055. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ070- 071. NJ...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR NJZ007-008. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR NJZ009. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR NJZ001. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ016>019. WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NJZ010-012- 013-015. DE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DEZ001. MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ008- 012-015-019-020. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ452>455. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST MONDAY FOR ANZ450-451. && $$ SYNOPSIS...HEAVENER/MEOLA NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...HEAVENER AVIATION...GORSE/HEAVENER MARINE...GORSE/HEAVENER/MEOLA
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1220 PM EST Sun Dec 8 2013 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1212 PM EST Sun Dec 8 2013 Wintry mix has turned to rain in the south and has dissipated to just some patches of light freezing drizzle in the north/west, so have canceled the advisory for the Bowling Green and Louisville areas. Have replaced it with a Special Weather Statement for the light patchy FZDZ. Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (18Z TAF Update)... Updated at 1218 PM EST Sun Dec 8 2013 The wintry mix has become very light across the region this afternoon, but a prolonged period of IFR cigs or even LIFR cigs appears increasingly likely tonight. These LIFR ceilings have already moved into KBWG, and will likely affect KLEX as well. As another disturbance pushes in from the southwest overnight, additional low-level moisture will work into the region. This will cause ceilings to remain IFR or LIFR through the overnight period, with even a few light showers possible around KLEX or KBWG. KSDF will be further removed from the deeper moisture overnight, so just expect IFR cigs and perhaps some isolated drizzle. Winds will be shifting from easterly to southerly to westerly by Monday morning. Wind speeds will be generally light, around 7 knots or less. Ceilings should slowly improve throughout the day on Monday, lifting to MVFR thresholds by the mid to late morning hours. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 6 PM EST this evening FOR KYZ035>037-039>043-046>049-054>057. WINTER WEATHER ADVISORY until 3 PM EST this afternoon FOR KYZ067. IN...NONE. && $$ Update.........KJD/13 Short Term.....JSD Long Term......RJS Aviation.......KJD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1213 PM EST Sun Dec 8 2013 ...Forecast Update... Issued at 1212 PM EST Sun Dec 8 2013 Wintry mix has turned to rain in the south and has dissipated to just some patches of light freezing drizzle in the north/west, so have canceled the advisory for the Bowling Green and Louisville areas. Have replaced it with a Special Weather Statement for the light patchy FZDZ. Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (12Z TAF Update)... Updated at 607 AM EST Sun Dec 8 2013 Light mixed wintry precipitation will continue through the morning hours at SDF and LEX. For BWG, light freezing rain will switch to just light rain around 17z. Ceilings will lower to low end MVFR or to IFR within this precipitation For BWG, Light sleet and freezing rain will continue with IFR ceilings through the mid to late morning hours, after which, it will switch over to just light rain and diminish. Precipitation rates will stay light enough so that visibilities will stay in the upper MVFR range. Light drizzle with continued IFR ceilings are likely this afternoon. Cloudy skies and possibly light drizzle will continue overnight with IFR ceilings. For LEX, Light sleet, possibly mixed at first with light snow will be ongoing right around the TAF issuance time. Ceilings will lower to IFR by 14z and continue this way through much of the day. This will change into light freezing rain which will continue through the morning hours, eventually changing to light rain or drizzle by mid afternoon. IFR ceilings are likely this evening and overnight. For SDF, Light sleet and snow will continue through the morning hours...possibly changing to light freezing rain or freezing drizzle by early afternoon. Precipitation rates will stay light, so that ground-based visibilities will stay high in the MVFR or even VFR range today. IFR ceilings are expected this afternoon and tonight. Northeast winds of 5 to 10 mph tonight will veer to easterly by morning. Winds will become southerly at around 5 mph this evening. In general, for the overnight period and through early Monday, IFR ceilings and possibly some MVFR visibilities will continue even with a general lack of precipitation. Ceilings will rise into the MVFR category for all TAF sites by Monday afternoon as winds become westerly at 5 to 10mph after noon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 6 PM EST this evening FOR KYZ035>037-039>043-046>049-054>057. WINTER WEATHER ADVISORY until 3 PM EST this afternoon FOR KYZ067. IN...NONE. && $$ Update.........13/KJD Short Term.....JSD Long Term......RJS Aviation.......JSD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
600 PM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES. A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM IMT-IWD. LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE. HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE 0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1 SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR. SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE SNOW LATE TONIGHT. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 ELOGATED AREA OF UPPER LEVEL TROUGHING STRETCHES FROM SKANDINAVIA AND FAR NORTHWEST RUSSIA ACROSS THE NORTH POLE AND ACROSS MUCH OF EASTERN CANADA AND AS FAR SOUTH AS THE WESTERN PORTIONS OF THE CONUS. CORE OF COLDEST AIR RESIDES FROM NORTHERN GREENLAND ACROSS CNTRL CANADA AND INTO THE NORTHERN PLAINS. H85 TEMP THIS MORNING AT KINL WAS -25C WHILE IT WAS -17C AT KGRB. DECENT AGREEMENT THAT UPCOMING WEEK WILL REMAIN CHILLY AS UPPER TROUGH BECOMES MORE CENTERED OVER HUDSON BAY ALLOWING MULTIPLE PUSHES OF ARCTIC AIR TO SWEEP ACROSS NORTHERN PLAINS AND GREAT LAKES IN NW FLOW ALOFT. STILL INDICATIONS THAT COLD STARTS TO RELAX NEXT WEEKEND AS TROUGHING REORIENTS FROM NORTH POLE TO DAVIS STRAIT AND GREENLAND WHICH ALLOWS FOR MORE OF A ZONAL WEST-NORTHWEST FLOW ALOFT ACROSS THE CONUS BY MIDDLE OF THE MONTH. FIRST CONCERNING THE LK EFFECT ON MONDAY NIGHT. INITIAL SHORTWAVE IN NW FLOW CURRENTLY OVER NORTHERN SASKATCHEWAN AND MANITOBA SWEEPS ACROSS LK SUPERIOR REGION MONDAY AFTN. EXPECT MINIMAL SYNOPTIC SUPPORT FOR ANY SNOW AS PVA/Q-VECTOR CONVERGENCE AT H7-H5/H85-H7 STAYS OVER LK SUPERIOR AND MAINLY NORTH. SFC LOW MOVING THROUGH ON MONDAY DEEPENS NORTH OF LK SUPERIOR TOWARD JAMES BAY BY MONDAY EVENING AS RESULT OF PVA/COLD AIR ADVECTION. RESULT IS INCREASING UNSTABLE WESTERLY LOW- LEVEL FLOW ACROSS LK SUPERIOR. NAM SOUNDINGS INDICATE VERY UNSTABLE CONDITIONS AS SHORTWAVE HELPS RAISE INVERSIONS TO OVER 7KFT WITH LAKE EQL/S OVER 13KFT AT CMX AND P59 AND STDM4. SFC-925MB STEERING WINDS VARY ENOUGH DURING PERIOD OF MOST FAVORABLE INSTABILITY/MOSITURE/CONVERGENCE TO PEG WHERE HEAVIEST SNOW WILL OCCUR. HIGH RES MODELS DO DIFFER HERE SOMEWHAT...WITH THE 12Z REGIONAL GEM KEEPING THE STRONGEST CONVERGENCE MAINLY ALONG THE NORTHWEST SHORE OF THE KEWEENAW THROUGH LATE AFTN...WHILE LOCAL WRF IS MORE ON THE SOUTHERN EDGE...SETTING UP DOMINANT BAND MAINLY TO SOUTH OF HOUGHTON AND HANCOCK. NAM AND NCEP WRF-ARW/NMM NESTS KIND OF IN BTWN THOSE IDEAS. GIVEN THE DEGREE OF OVERWATER INSTABILITY... POTENTIAL CERTAINTY THERE FOR TOTAL SNOW MONDAY AFTN THROUGH MONDAY EVENING TO EXCEED A FOOT...IF THE BAND CAN PERSIST IN ONE LOCATION FOR A WHILE. AT THE LEAST...MOST AREAS WILL SEE BURSTS OF HEAVIER SNOW ALONG WITH STRONG/GUSTY WEST WINDS TO 40 MPH AND A LOT OF BLOWING SNOW AND POOR VSBY. IN THE HEAVIER SNOW BAND...WHITEOUTS MAY OCCUR MONDAY AFTN INTO MONDAY EVENING. COORD WITH SHORT TERM FORECASTER AND DECIDED TO LEAVE GOING LK EFFECT SNOW WATCH. NOT REALLY A QUESTION IF HEAVY LES/BLSN WILL OCCUR...BUT MORE ONE OF WHERE THAT STRONG CONVERGENCE BAND WILL DEVELOP. WILL LET MID SHIFT TAKE ANOTHER CRACK AT PINNING DOWN LOCATION OF THE HEAVIER SNOW BAND. ATTN LATER MONDAY NIGHT WILL BE ON SHORTWAVE PUSHING IN ACROSS NORTHERN PLAINS AND ASSOCIATED SFC TROUGH. FIRST IMPACT FM THIS WAVE WILL BE TO BACK WINDS SW...ALLOWING MOST OF HEAVIER LK EFFECT SNOW TO PUSH OUT OVER LK SUPERIOR OFF THE KEWEENAW PENINSULA...THUS THE ENDING TIME OF LATE MONDAY EVENING FOR LAKE EFFECT SNOW WATCH. RIGHT AS THE LK EFFECT DIMINISHES FOR A WHILE...STILL APPEARS THAT LGT SYNOPTIC SNOW WILL IMPACT MUCH OF CWA MAINLY IN THE MORNING. BRIEF NOTE ABOUT WIND CHILLS FOR MONDAY NIGHT...INCREASING CLOUDS AHEAD OF THE SYSTEM LATER MONDAY NIGHT SHOULD ALLOW TEMPS TO BEGIN TO RISE. HAVE MINS WELL BLO ZERO...EVEN LESS THAN 10 BLO THROUGH EARLY MORNING...THEN WITH THE ARRIVAL OF CLOUDS AND MORE WIND...EXPECT TEMPS TO RISE TOWARD ZERO BY DAYBREAK ON TUESDAY. WILL BE CLOSE CALL ON WIND CHILL READINGS NEAR CRITERIA BUT TEMPS MAY WARM JUST ENOUGH TO KEEP WIND CHILLS GREATER THAN 25 BLO. AT THE LEAST...WIND CHILLS WILL STILL BE A RATHER CHILLY 10 TO 20 BLO FOR MAJORITY OF WEST HALF OF UPR MICHIGAN. AS SFC LOW STRENGTHENS...MOISTURE/TEMPERATURE ADVECTION AHEAD OF WAVE MIGHT RESULT IN MORE WIDESPREAD SNOW OVER EASTERN CWA LATE MORNING INTO EARLY AFTN...WHERE A FEW INCHES OF SNOW COULD OCCUR. OTHERWISE...EXPECT LESS THAN 1 INCH FOR THE CWA FROM THE SYSTEM. ONCE THE SHORTWAVE AND SFC LOW CROSS THE AREA...SFC TROUGH ELONGATES ACROSS SOUTHERN HALF OF LK SUPERIOR AND EVENTUALLY INTO NORTHERN TIER OF UPR MICHIGAN. RESULT WILL BE LK EFFECT...MOSTLY OF MODERATE INTENSITY...FOR THE WNW-NW FLOW AREAS. MOST CONCENTRATED/HEAVIER SNOW SHOWERS LIKELY FOR THE SNOWBELTS OF ONTONAGON COUNTY FROM WHITE PINE TO ROCKLAND AND ALSO TO THE EAST OF MUNISING AND TO THE NORTH OF NEWBERRY...INCLUDING GRAND MARAIS. PERSISTENT LK EFFECT SETUP CONTINUES THROUGH MUCH OF WEDNESDAY WITH INVERSIONS 5-8KFT AND MORE THAN SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS ARE NEAR -25C. GIVEN SUCH COLD TEMPS THOUGH...SNOW WILL BE VERY FINE AND MAIN ISSUE IN THE LK EFFECT AREAS WILL BE POWDERY SNOW BEING BLOWN AROUND BY GUSTY WINDS RESULTING IN BLSN/POOR VSBY. AWAY FM THE LK EFFECT COLD AIRMASS FIRMLY ENTRENCHED. SOME AREAS OF WESTERN CWA MAY NOT REACH ZERO ON WEDNESDAY AFTN. ANOTHER SYSTEM APPROACHING IN THE ACTIVE NW FLOW ALOFT COMES IN BY THURSDAY MORNING. WINDS SHOULD BACK ENOUGH SW TO PUSH MOST OF THE LK EFFECT OFFSHORE EXCEPT OVER THE KEWEENAW. HIGH PRESSURE RIDGE IN VCNTY FIRST PART OF WED NIGHT WITH SUCH COLD AIRMASS SUGGESTS THAT MINS COULD BE VERY LOW. LOWERED TEMPS TOWARD COLDER MOS NUMBERS...AND FURTHER TWEAKED COLD SPOTS IN THE INTERIOR TOWARD 20 BLO ZERO. MAY BE SIMILAR SETUP TO MONDAY NIGHT/TUESDAY NIGHT WHERE TEMPS RISE LATE. MAIN CHANGE BESIDES LOWERING TEMPS WAS TO LOWER WIND SPEEDS TOO AS WINDS MAY TRY TO GO CALM WITH THE RIDGE AROUND TO START THE NIGHT. THUS...MAY NOT SEE WIND CHILL ISSUES UNLESS THAT INCOMING SYSTEM TRENDS STRONGER. IN WAKE OF THAT SYSTEM...SFC TROUGH SINKS ACROSS LK SUPERIOR AND UPR MICHIGAN WHICH TURNS WINDS MORE NNW/N LATER THURSDAY AND FRIDAY. KEPT IDEA OF INCREASING POPS FOR LK EFFECT ALONG MUCH OF LK SUPERIOR COMPARED TO CONSENSUS POPS. MODELS HINT THAT WARMER AIR COULD TRY TO WORK IN BY NEXT WEEKEND...AT LEAST RELATIVELY WARMER...AS FLOW SHOWS SIGNS OF TRYING TO BECOME MORE ZONAL. MORE WIDESPREAD AREA OF WARM AIR ADVECTION SNOW MAY TRY TO DEVELOP CLOSE TO THE REGION ALONG RETREATING ARCTIC AIRMASS. THOSE TYPE OF DETAILS WILL BE HANDLED BY LOW CHANCE POPS FOR THE TIME BEING. TEMPS THOUGH WARMER WILL STILL BE RUNNING BLO NORMAL THROUGH THE END OF THE EXTENDED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 600 PM EST SUN DEC 8 2013 WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS CONTINUING. IFR CONDITIONS ARE MOST LIKELY TO DEVELOP AT SAW. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH VLIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST AND BECOME GUSTY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 400 PM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND OF GALES TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 9 AM EST MONDAY FOR MIZ007-014-085. LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ244-245- 265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ MONDAY TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING FROM 4 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES. A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM IMT-IWD. LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE. HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE 0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1 SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR. SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE SNOW LATE TONIGHT. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 ELOGATED AREA OF UPPER LEVEL TROUGHING STRETCHES FROM SKANDINAVIA AND FAR NORTHWEST RUSSIA ACROSS THE NORTH POLE AND ACROSS MUCH OF EASTERN CANADA AND AS FAR SOUTH AS THE WESTERN PORTIONS OF THE CONUS. CORE OF COLDEST AIR RESIDES FROM NORTHERN GREENLAND ACROSS CNTRL CANADA AND INTO THE NORTHERN PLAINS. H85 TEMP THIS MORNING AT KINL WAS -25C WHILE IT WAS -17C AT KGRB. DECENT AGREEMENT THAT UPCOMING WEEK WILL REMAIN CHILLY AS UPPER TROUGH BECOMES MORE CENTERED OVER HUDSON BAY ALLOWING MULTIPLE PUSHES OF ARCTIC AIR TO SWEEP ACROSS NORTHERN PLAINS AND GREAT LAKES IN NW FLOW ALOFT. STILL INDICATIONS THAT COLD STARTS TO RELAX NEXT WEEKEND AS TROUGHING REORIENTS FROM NORTH POLE TO DAVIS STRAIT AND GREENLAND WHICH ALLOWS FOR MORE OF A ZONAL WEST-NORTHWEST FLOW ALOFT ACROSS THE CONUS BY MIDDLE OF THE MONTH. FIRST CONCERNING THE LK EFFECT ON MONDAY NIGHT. INITIAL SHORTWAVE IN NW FLOW CURRENTLY OVER NORTHERN SASKATCHEWAN AND MANITOBA SWEEPS ACROSS LK SUPERIOR REGION MONDAY AFTN. EXPECT MINIMAL SYNOPTIC SUPPORT FOR ANY SNOW AS PVA/Q-VECTOR CONVERGENCE AT H7-H5/H85-H7 STAYS OVER LK SUPERIOR AND MAINLY NORTH. SFC LOW MOVING THROUGH ON MONDAY DEEPENS NORTH OF LK SUPERIOR TOWARD JAMES BAY BY MONDAY EVENING AS RESULT OF PVA/COLD AIR ADVECTION. RESULT IS INCREASING UNSTABLE WESTERLY LOW- LEVEL FLOW ACROSS LK SUPERIOR. NAM SOUNDINGS INDICATE VERY UNSTABLE CONDITIONS AS SHORTWAVE HELPS RAISE INVERSIONS TO OVER 7KFT WITH LAKE EQL/S OVER 13KFT AT CMX AND P59 AND STDM4. SFC-925MB STEERING WINDS VARY ENOUGH DURING PERIOD OF MOST FAVORABLE INSTABILITY/MOSITURE/CONVERGENCE TO PEG WHERE HEAVIEST SNOW WILL OCCUR. HIGH RES MODELS DO DIFFER HERE SOMEWHAT...WITH THE 12Z REGIONAL GEM KEEPING THE STRONGEST CONVERGENCE MAINLY ALONG THE NORTHWEST SHORE OF THE KEWEENAW THROUGH LATE AFTN...WHILE LOCAL WRF IS MORE ON THE SOUTHERN EDGE...SETTING UP DOMINANT BAND MAINLY TO SOUTH OF HOUGHTON AND HANCOCK. NAM AND NCEP WRF-ARW/NMM NESTS KIND OF IN BTWN THOSE IDEAS. GIVEN THE DEGREE OF OVERWATER INSTABILITY... POTENTIAL CERTAINTY THERE FOR TOTAL SNOW MONDAY AFTN THROUGH MONDAY EVENING TO EXCEED A FOOT...IF THE BAND CAN PERSIST IN ONE LOCATION FOR A WHILE. AT THE LEAST...MOST AREAS WILL SEE BURSTS OF HEAVIER SNOW ALONG WITH STRONG/GUSTY WEST WINDS TO 40 MPH AND A LOT OF BLOWING SNOW AND POOR VSBY. IN THE HEAVIER SNOW BAND...WHITEOUTS MAY OCCUR MONDAY AFTN INTO MONDAY EVENING. COORD WITH SHORT TERM FORECASTER AND DECIDED TO LEAVE GOING LK EFFECT SNOW WATCH. NOT REALLY A QUESTION IF HEAVY LES/BLSN WILL OCCUR...BUT MORE ONE OF WHERE THAT STRONG CONVERGENCE BAND WILL DEVELOP. WILL LET MID SHIFT TAKE ANOTHER CRACK AT PINNING DOWN LOCATION OF THE HEAVIER SNOW BAND. ATTN LATER MONDAY NIGHT WILL BE ON SHORTWAVE PUSHING IN ACROSS NORTHERN PLAINS AND ASSOCIATED SFC TROUGH. FIRST IMPACT FM THIS WAVE WILL BE TO BACK WINDS SW...ALLOWING MOST OF HEAVIER LK EFFECT SNOW TO PUSH OUT OVER LK SUPERIOR OFF THE KEWEENAW PENINSULA...THUS THE ENDING TIME OF LATE MONDAY EVENING FOR LAKE EFFECT SNOW WATCH. RIGHT AS THE LK EFFECT DIMINISHES FOR A WHILE...STILL APPEARS THAT LGT SYNOPTIC SNOW WILL IMPACT MUCH OF CWA MAINLY IN THE MORNING. BRIEF NOTE ABOUT WIND CHILLS FOR MONDAY NIGHT...INCREASING CLOUDS AHEAD OF THE SYSTEM LATER MONDAY NIGHT SHOULD ALLOW TEMPS TO BEGIN TO RISE. HAVE MINS WELL BLO ZERO...EVEN LESS THAN 10 BLO THROUGH EARLY MORNING...THEN WITH THE ARRIVAL OF CLOUDS AND MORE WIND...EXPECT TEMPS TO RISE TOWARD ZERO BY DAYBREAK ON TUESDAY. WILL BE CLOSE CALL ON WIND CHILL READINGS NEAR CRITERIA BUT TEMPS MAY WARM JUST ENOUGH TO KEEP WIND CHILLS GREATER THAN 25 BLO. AT THE LEAST...WIND CHILLS WILL STILL BE A RATHER CHILLY 10 TO 20 BLO FOR MAJORITY OF WEST HALF OF UPR MICHIGAN. AS SFC LOW STRENGTHENS...MOISTURE/TEMPERATURE ADVECTION AHEAD OF WAVE MIGHT RESULT IN MORE WIDESPREAD SNOW OVER EASTERN CWA LATE MORNING INTO EARLY AFTN...WHERE A FEW INCHES OF SNOW COULD OCCUR. OTHERWISE...EXPECT LESS THAN 1 INCH FOR THE CWA FROM THE SYSTEM. ONCE THE SHORTWAVE AND SFC LOW CROSS THE AREA...SFC TROUGH ELONGATES ACROSS SOUTHERN HALF OF LK SUPERIOR AND EVENTUALLY INTO NORTHERN TIER OF UPR MICHIGAN. RESULT WILL BE LK EFFECT...MOSTLY OF MODERATE INTENSITY...FOR THE WNW-NW FLOW AREAS. MOST CONCENTRATED/HEAVIER SNOW SHOWERS LIKELY FOR THE SNOWBELTS OF ONTONAGON COUNTY FROM WHITE PINE TO ROCKLAND AND ALSO TO THE EAST OF MUNISING AND TO THE NORTH OF NEWBERRY...INCLUDING GRAND MARAIS. PERSISTENT LK EFFECT SETUP CONTINUES THROUGH MUCH OF WEDNESDAY WITH INVERSIONS 5-8KFT AND MORE THAN SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS ARE NEAR -25C. GIVEN SUCH COLD TEMPS THOUGH...SNOW WILL BE VERY FINE AND MAIN ISSUE IN THE LK EFFECT AREAS WILL BE POWDERY SNOW BEING BLOWN AROUND BY GUSTY WINDS RESULTING IN BLSN/POOR VSBY. AWAY FM THE LK EFFECT COLD AIRMASS FIRMLY ENTRENCHED. SOME AREAS OF WESTERN CWA MAY NOT REACH ZERO ON WEDNESDAY AFTN. ANOTHER SYSTEM APPROACHING IN THE ACTIVE NW FLOW ALOFT COMES IN BY THURSDAY MORNING. WINDS SHOULD BACK ENOUGH SW TO PUSH MOST OF THE LK EFFECT OFFSHORE EXCEPT OVER THE KEWEENAW. HIGH PRESSURE RIDGE IN VCNTY FIRST PART OF WED NIGHT WITH SUCH COLD AIRMASS SUGGESTS THAT MINS COULD BE VERY LOW. LOWERED TEMPS TOWARD COLDER MOS NUMBERS...AND FURTHER TWEAKED COLD SPOTS IN THE INTERIOR TOWARD 20 BLO ZERO. MAY BE SIMILAR SETUP TO MONDAY NIGHT/TUESDAY NIGHT WHERE TEMPS RISE LATE. MAIN CHANGE BESIDES LOWERING TEMPS WAS TO LOWER WIND SPEEDS TOO AS WINDS MAY TRY TO GO CALM WITH THE RIDGE AROUND TO START THE NIGHT. THUS...MAY NOT SEE WIND CHILL ISSUES UNLESS THAT INCOMING SYSTEM TRENDS STRONGER. IN WAKE OF THAT SYSTEM...SFC TROUGH SINKS ACROSS LK SUPERIOR AND UPR MICHIGAN WHICH TURNS WINDS MORE NNW/N LATER THURSDAY AND FRIDAY. KEPT IDEA OF INCREASING POPS FOR LK EFFECT ALONG MUCH OF LK SUPERIOR COMPARED TO CONSENSUS POPS. MODELS HINT THAT WARMER AIR COULD TRY TO WORK IN BY NEXT WEEKEND...AT LEAST RELATIVELY WARMER...AS FLOW SHOWS SIGNS OF TRYING TO BECOME MORE ZONAL. MORE WIDESPREAD AREA OF WARM AIR ADVECTION SNOW MAY TRY TO DEVELOP CLOSE TO THE REGION ALONG RETREATING ARCTIC AIRMASS. THOSE TYPE OF DETAILS WILL BE HANDLED BY LOW CHANCE POPS FOR THE TIME BEING. TEMPS THOUGH WARMER WILL STILL BE RUNNING BLO NORMAL THROUGH THE END OF THE EXTENDED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1218 PM EST SUN DEC 8 2013 A DISTURBANCE AND WIDESPREAD AREA OF LIGHT SNOW WILL MOVE FROM WI INTO UPPER MICHIGAN THIS AFTERNOON. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTERNOON...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH LIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 400 PM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND OF GALES TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ244-245- 265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ MONDAY TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING FROM 4 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1219 PM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1218 PM EST SUN DEC 8 2013 A DISTURBANCE AND WIDESPREAD AREA OF LIGHT SNOW WILL MOVE FROM WI INTO UPPER MICHIGAN THIS AFTERNOON. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTERNOON...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH LIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR LSZ244-245. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...JLB MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
157 PM CST SUN DEC 8 2013 .DISCUSSION... UPDATED TO DROP WINTER WEATHER ADVISORY ACROSS THE AREA. WITH VISILIBITIES NOW AT OR ABOVE 2 SM IN MOST LOCATIONS...ONLY LIGHT ACCUMULATIONS OF A COUPLE TENTHS OF AN INCH ARE EXPECTED. SECONDARY BATCH OF SNOW CURRENTLY IN SOUTHEAST NEB IS PROGGED TO WEAKEN AS IT APPROACHES EASTERN NEB...BUT IT MAY BRING YET ANOTHER TENTH OR TWO OF SNOW. OVERALL...WITH THE ACCUMULATING SNOW DIMINISHING...THE NEED FOR AN ADVISORY HAS DIMINISHED AS WELL. WITH COMPACTION AND SETTLING OF SNOW...MOST LOCATIONS HAVE LIKELY SEEN THEIR PEAK SNOW ACCUMULATIONS. MAYES && .PREV DISCUSSION... /ISSUED 1125 AM CST SUN DEC 8 2013/ AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. LIGHT TO MODERATE SNOW CONTINUES AT ALL SITES...BUT VIS AND CEILINGS SHOULD GRADUALLY IMPROVE THROUGH THE AFTERNOON. KOMA MAY HOLD ON TO SNOW UNTIL AT LEAST AROUND 00Z...BUT OTHER SITES SHOULD TAPER TO FLURRIES BEFORE THEN. OVERNIGHT...CEILINGS SHOULD DECREASE...WHILE WINDS WILL INCREASE OUT OF THE NORTHWEST. HAVE ONLY BROUGHT WINDS ABOVE 12KT AT KOFK...WITH KOMA/KLNK AT AROUND 10KT...AND WINDS SHOULD BEING TO DECREASE BY AROUND 18Z MONDAY. MAYES PREV DISCUSSION... /ISSUED 854 AM CST SUN DEC 8 2013/ DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1125 AM CST SUN DEC 8 2013 .AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. LIGHT TO MODERATE SNOW CONTINUES AT ALL SITES...BUT VIS AND CEILINGS SHOULD GRADUALLY IMPROVE THROUGH THE AFTERNOON. KOMA MAY HOLD ON TO SNOW UNTIL AT LEAST AROUND 00Z...BUT OTHER SITES SHOULD TAPER TO FLURRIES BEFORE THEN. OVERNIGHT...CEILINGS SHOULD DECREASE...WHILE WINDS WILL INCREASE OUT OF THE NORTHWEST. HAVE ONLY BROUGHT WINDS ABOVE 12KT AT KOFK...WITH KOMA/KLNK AT AROUND 10KT...AND WINDS SHOULD BEING TO DECREASE BY AROUND 18Z MONDAY. MAYES && .PREV DISCUSSION... /ISSUED 854 AM CST SUN DEC 8 2013/ DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>093. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
101 PM MST SUN DEC 8 2013 .UPDATE... UPDATED TO CANCEL WIND AND WINTER WEATHER HIGHLIGHTS. FRONTAL BAND HAS WEAKENED SIGNIFICANTLY AS IT MOVED WELL SOUTH OF THE UPPER LEVEL FORCING OVER COLORADO. SFC COLD FRONT IS NOW MAINLY A STALLED WEST TO EAST ORIENTED TEMPERATURE BOUNDARY FROM QUEMADO TO SOCORRO TO CLINES CORNERS TO JUST N/NW OF TUCUMCARI. ISOALTED SNOW SHOWERS WILL CONTINUE OVER THE WESTERN HIGHLANDS AND MTNS AND OVER THE CENTRAL HIGHLANDS THROUGH THE AFTERNOON. THE STALLED SFC FRONT DRAPED FROM WEST TO EAST EXPECTED TO SET THE STAGE FOR MONDAY. 33 && .PREV DISCUSSION...1055 AM MST SUN DEC 8 2013... .AVIATION... 18Z TAF CYCLE LIFR CONDITIONS IN FREEZING FOG AT KROW TO IMPROVE TO VFR BY 20Z THEN REMAIN VFR THROUGH THE TAF PERIOD WITH THE POTENTIAL FOR MVFR CONDITIONS MONDAY MORNING. VFR CONDITIONS FORECAST TO PERSIST AT KFMN...BUT MORE COMPLEX FORECAST FOR KGUP...KABQ...KAEG...KSAF AND KTCC AS ANOTHER SHORTWAVE TROUGH DROPS INTO THE REGION OVERNIGHT THROUGH MONDAY. LIGHT SNOW WITH MVFR CIGS/VSBYS FORECAST TO DEVELOP OVERNIGHT...WITH IFR CONDITIONS POSSIBLE. IMPROVEMENT... IF ANY...MONDAY MORNING WILL BE SLOW AT KGUP...KABQ...KAEG AND KSAF. LIKELY AN ALL-DAY SCENARIO AT KTCC WITH DETERIORATING CONDITIONS. WIND GUSTS TO BETWEEN 35-40KTS AT KLVS AND KTCC THIS AFTERNOON WILL DIMINISH QUICKLY BY EARLY EVENING. 11 .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1055 AM MST SUN DEC 8 2013 .AVIATION... 18Z TAF CYCLE LIFR CONDITIONS IN FREEZING FOG AT KROW TO IMPROVE TO VFR BY 20Z THEN REMAIN VFR THROUGH THE TAF PERIOD WITH THE POTENTIAL FOR MVFR CONDITIONS MONDAY MORNING. VFR CONDITIONS FORECAST TO PERSIST AT KFMN...BUT MORE COMPLEX FORECAST FOR KGUP...KABQ...KAEG...KSAF AND KTCC AS ANOTHER SHORTWAVE TROUGH DROPS INTO THE REGION OVERNIGHT THROUGH MONDAY. LIGHT SNOW WITH MVFR CIGS/VSBYS FORECAST TO DEVELOP OVERNIGHT...WITH IFR CONDITIONS POSSIBLE. IMPROVEMENT... IF ANY...MONDAY MORNING WILL BE SLOW AT KGUP...KABQ...KAEG AND KSAF. LIKELY AN ALL-DAY SCENARIO AT KTCC WITH DETERIORATING CONDITIONS. WIND GUSTS TO BETWEEN 35-40KTS AT KLVS AND KTCC THIS AFTERNOON WILL DIMINISH QUICKLY BY EARLY EVENING. 11 && .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 AM TO 11 PM MST MONDAY FOR THE FOLLOWING ZONES...NMZ518>526-529-531>539. WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM MST MONDAY FOR THE FOLLOWING ZONES...NMZ505>509. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$ 33
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 PM EST SUN DEC 8 2013 .SYNOPSIS... CHILLY AND DAMP CONDITIONS WILL PREVAIL TODAY BEFORE A WARM FRONT BRINGS A SHORT-LIVED WARM-UP ON MONDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...BRINGING A REINFORCEMENT OF COOLER AIR THROUGH MID WEEK. ANOTHER STORM SYSTEM MAY BRING RAIN TO THE REGION NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY...PERSISTENCE EMPLOYED FOR THE NEAR TERM UPDATE AS THE METEOROLOGICAL SET-UP SUPPORTS A COOL AND WET REGIME TO PREVAIL ALL DAY AND OVERNIGHT. NEAR TERM MODEL DATA HOWEVER POINTS TO ATYPICAL TEMPERATURE CURVES TONIGHT...WITH A SLOW CLIMB FROM THE MIDDLE AND UPPER 40S TO AROUND 50 DEGREES BY DAYBREAK MONDAY AS SW FLOW ALOFT STRENGTHENS AND SCOURS THE SHALLOW AND COOL WEDGE OF MARITIME INFLUENCE. HOW QUICKLY THIS OCCURS REMAINS UP FOR ASSESSMENT...BUT IT APPEARS THE WEDGE WILL REMAIN ENTRENCHED OVER THE FORECAST AREA THROUGH DAYBREAK MONDAY. THIS MAKE TEMP AND WIND FORECASTS A BIT MORE PREDICTABLE THAN THE TRANSITION OF WARMING ON MONDAY MORNING. MAXIMUM TEMPERATURES AS A RESULT WILL LIKELY OCCUR FOR TODAYS 24 HOUR CALENDER PERIOD JUST PRIOR TO 12Z/7AM MONDAY MORNING. PRECIPITATION-WISE THE OVER-RUNNING WEDGE PATTERN WILL SUPPORT OCCASIONAL DRIZZLE AREA-WIDE THROUGH TONIGHT. IN FACT AS THE WARM FRONTAL TYPE PROCESS GEARS UP EARLY ON MONDAY...AREAS OF DENSE FOG AND DRIZZLE MAY EXPAND OVER THE FORECAST AREA TO START THE WEEK. P-TYPE ANALYSIS SHOWS THAT BOTH STRATIFORM AND CONVECTIVE TYPE RAINFALL WILL PREVAIL OVER THE AREA THROUGH TONIGHT...BUT NOT A LARGE OR SIGNIFICANT CONTRIBUTION FROM EITHER. WILL CONTINUE TO ADVERTISE SCATTERED TO LIKELY POP VALUES TO HIGHLIGHT DECENT PROBABILITIES OF MEASURABLE PRECIPITATION HOWEVER ACCOMPANIED BY INTERMITTENT DRIZZLE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...SHARP CLASSIC COLD AIR DAMMING EVENT WILL COME TO AN END EARLY IN THE PERIOD WITH THE FORECAST DILEMMA BEING FORECAST HIGHS FOR MONDAY. THE MET CONTINUES TO ADVERTISE THE COOLER NUMBERS AND WITH LINGERING LOW LEVEL MOISTURE AND NEARING THE WINTER SOLSTICE...THESE SEEM MORE REASONABLE ALTHOUGH WITH ANY APPRECIABLE CLOUD OR EARLY BREAKS...VERY WARM TEMPERATURES IN THE 850-900MB LAYER COULD MIX DOWN. THE FORECAST SOLUTIONS REGARDING THE FRONT TUESDAY CONTINUE TO WAVER AND SLOW THE PROGRESSION OF THE FRONT. IN FACT...THE GFS SHOWS A SECONDARY AREA OF QPF DEVELOPING WITH THE SOUTHWEST FLOW WEDNESDAY THUS SLOWING THE FRONT FOR TUESDAY. THIS IS THE FIRST CYCLE THIS HAS APPEARED SO I DID MAINTAIN THE LIKELY POPS FOR TUESDAY AND INCREASED THE LONGEVITY OF THE MOISTURE FOR TUESDAY EVENING. NO CHANGES TO TEMPERATURE FORECAST FOR TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...CONFIDENCE HAS WALKED BACK SLIGHTLY WITH REGARDS TO THE EVENTS FOR THE EXTENDED FORECAST. THE NEW AND WETTER SOLUTION AS ADVERTISED BY THE GFS OPERATIONAL PUTS WEDNESDAY IN QUESTION ALTHOUGH I DID NOT CHANGE THE DRY FORECAST AT LEAST FOR NOW TO SEE IF MORE SOLUTIONS COME IN SIMILAR. THE GFS ALSO CONTINUES TO SHOW A FAIRLY STRONG SOUTHERN STREAM SYSTEM FOR THE END OF THE WEEK INSTEAD OF THE WEAKLY FORCED COASTAL TROUGH. I HAVE ALONG WITH ADJACENT OFFICES INCREASED POPS AND CLOUD COVER FOR THE END OF THE PERIOD. NO CHANGES TO THE TEMPERATURE FORECAST ALTHOUGH ONCE AGAIN THE READINGS MAY SEE SOME CHANGES DEPENDING ON THE MASS FIELDS. && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 18Z...WEDGE WILL LIKELY REMAIN IN PLACE THROUGH MUCH OF THE FORECAST PERIOD. HIGH CONFIDENCE FOR IFR CONDITIONS THIS AFTERNOON...POSSIBLY BECOMING VLIFR TONIGHT. THE WARM AIR WILL START TO OVERRIDE THE WEDGE LATE TONIGHT. THE RISING DEWPOINTS COUPLED WITH DIURNAL AFFECTS SHOULD BE A GOOD RECIPE FOR DENSE FOG TONIGHT. WOULD NOT BE SURPRISED TO SEE SOME M1/4SM ESPECIALLY OVER THE SOUTHERN TERMINALS. MONDAY...DENSE FOG WILL LINGER THROUGH MID MORNING AT THE COASTAL TERMINALS...LIFTING AS WINDS SHIFT TO THE SOUTHWEST AS THE WEDGE ERODES. INLAND TERMINALS MAY SEE LIFR/IFR CONDITIONS THROUGH THE END OF THE FORECAST PERIOD AS THE WEDGE IN TYPICAL FASHION WILL BE STUBBORN TO RETREAT. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH TUESDAY WITH LIFR/IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY. SHOWERS LIKELY TUESDAY FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE. MODERATE CONFIDENCE FOR VFR CONDITIONS WEDNESDAY THROUGH FRIDAY...EXCEPT POSSIBLY THE COAST WEDNESDAY NIGHT. SHOWERS POSSIBLE SATURDAY. && .MARINE... NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1025 AM SUNDAY...THE SCA HAS BEEN EXTENDED TO MID- AFTERNOON TODAY FOR ALL WATERS. THE NE WINDS CONTINUE TO HOWL AT 15 TO 25 KT WITH GUSTS APPROACHING 30 KT OFF CAPE FEAR EARLY THIS MORNING. WITH A SLIGHTLY SLOWER BREAKDOWN IN THE WEDGE BEING FORECAST DURING THIS PERIOD...HAVE SLOWED THE DIMINISHING TREND OF THE NE WINDS ACROSS THE LOCAL WATERS TODAY THROUGH TONIGHT. THIS IS DEPICTED WELL BY THE HOURLY HRRR MODEL RUNS ILLUSTRATING PROGGED SFC WINDS. THIS WILL ALSO PRODUCE A SLOWER SUBSIDING TREND TO THE SIGNIFICANT SEAS FROM ROUGHLY 4 TO 7 FT EARLY THIS AM...TO 2 TO 5 FT BY SUNDAY EVENING. THE MAKE-UP OF THE SIGNIFICANT SEAS WILL REMAIN FROM THE LOCALLY PRODUCED WIND DRIVEN VARIETY...WITH AVERAGE PERIODS AROUND 5 SECONDS. SEA FOG MAY BECOME AN ISSUE ONCE AGAIN DURING THE PRE-DAWN MONDAY HRS BUT LIKELY HOLD OFF INTO THE NEXT PERIOD WHEN S-SW WINDS ACROSS LOCAL SSTS IN THE 50S OCCUR. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...LIGHT AND ESSENTIALLY VARIABLE WINDS WILL QUICKLY FIND DEFINITION AS A SOUTHWEST FLOW OF 15-20 KNOTS DEVELOPS MIDDAY MONDAY. THIS FLOW WILL CONTINUE THROUGH MOST OF THE DAY TUESDAY BEFORE A LONG ADVERTISED FRONT MOVES ACROSS THE WATERS. BY 0600 UTC WEDNESDAY WINDS WILL BE NORTH ACROSS ALL WATERS WITH THE SAME 15-20 KNOTS. THE CHANGE IN FETCH AND THE FACT WINDS SEEM TO REMAIN CAPPED AT 20 KNOTS SHOULD KEEP SEAS BELOW FLAG CRITERIA IN A 2-4 FOOT RANGE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...A NORTH TO NORTHEASTERLY FLOW WILL GREET MARINERS INITIALLY WITH A FEW HOURS OF 15-20 KNOTS DIMINISHING SLIGHTLY TO 10-15 KNOTS BY WEDNESDAY EVENING. SLOW MOVING HIGH PRESSURE AND LOW PRESSURE WELL OFFSHORE WILL KEEP THIS FLOW IN PLACE THROUGH THURSDAY. SEAS SHOULD REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. && $$ NEAR TERM...DOUG/MJC SHORT TERM...SHK LONG TERM...SHK AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 PM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE TRAVELING UP THE APPALACHIANS WILL BRING A MIXTURE OF WINTRY PRECIPITATION TODAY INTO TONIGHT. HIGH PRESSURE WILL TRY TO BUILD IN ON MONDAY...BUT ANOTHER WEAK SYSTEM WILL AFFECT THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DECENT ISENTROPIC LIFT COMBINING WITH UPR LEVEL DIVERGENCE FROM THE RR QUAD ENTRANCE REGION OF UPR LEVEL JET WILL PRODUCE WIDESPREAD PCPN ACRS THE REGION THIS MORNING INTO THE FIRST PART OF THIS AFTERNOON. WAA WILL GRADUALLY WARM ATMOSPHERIC COLUMN ALOFT FROM SE TO NW THROUGH THE DAY. AS THIS OCCURS...SNOW WILL TRANSITION TO A MIXTURE OF SLEET AND FREEZING RAIN. IT SHOULD WARM UP ENOUGH IN THE FAR SE LATE THIS AFTERNOON FOR LIQUID PCPN. UPDATE THIS MORNING WAS TO BUMP UP SNOWFALL AMOUNTS A BIT IN THE SE CWFA AS SOME BURSTS OF MODERATE SNOW HAS ALREADY RESULTED IN ACCUMS AROUND AN INCH. SO...2 TO 3 LOOKS GOOD HERE WITH 1 TO 2 FARTHER NORTH IN DAYTON AND COLUMBUS METROS AND LESS THAN AN INCH NORTHWEST. LATEST MODEL INDICATE THAT WE COULD END UP WITH LIGHTER PCPN THIS EVENING/OVERNIGHT OVER MUCH OF THE REGION DUE TO DEEP MOISTURE EXITING AND FORCING REMAINING FOCUSED NEAR THE SE WITH A LOW LEVEL JET. WITH WARM TEMPS ALOFT AND SFC TEMPS NEAR OR SLIGHTLY BELOW FREEZING WILL RESULT IN EITHER LIGHT FREEZING RAIN OR FREEZING DRIZZLE. HEADLINES WILL HAVE TO BE ADJUSTED AT SOME POINT. TOSSED AROUND ADDING OUR NW CWFA IN AN ADVISORY...BUT WILL WAIT FOR SOME NEWER MODEL RUNS TO SEE IF PCPN WILL BE ENOUGH TO DO SO. TEMPS STARTING OUT COLD WITH ANY LIGHT LIQUID PCPN WITH SFC TEMPS BELOW FREEZING COULD CAUSE SOME ISSUES ON UNTREATED SIDEWALKS AND ROADS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE DEEP MOISTURE BEGINS TO BE SHUNTED E AT THE BEGINNING OF THE PERIOD...LEAVING THE W WITH VERY SHALLOW MOISTURE AND WEAKENING LIFT. THIS IS A SETUP FOR MORE OF A FZDZ/FZRA SCENARIO AS COMPARED TO SN/PL. THEREFORE BEGAN TO LOWER THE POPS IN THE W AND INTRODUCED MORE OF THE FZDZ/FZRA. EXPECT MUCH OF THE AREA TO MAKE THE CHANGE OVER AS TONIGHT PROGRESSES. THE EXCEPTION WILL BE THE SE/E WHERE TEMPERATURES MIGHT STAY UP ALL NIGHT THEREFORE STAYING ALL RAIN. THE ADVISORY IN THOSE LOCATIONS MIGHT BE TOO LONG...BUT WILL NOT CHANGE THE TIMING RIGHT NOW. INSTEAD WILL LET LATER SHIFTS CANCEL IT IF IT IS NOT NEEDED. LOWS TONIGHT SHOULD STAY UP IN THE LOWER TO MID 30S IN THE SE...BUT WILL FALL INTO THE UPPER 20S BACK TO THE W AS THE COOLER AIR WORKS IN ON THE BACKSIDE OF THE SYSTEM AS THE SYSTEM SLIDES E EARLY MONDAY...THE REGION WILL BE STUCK UNDER A SUBSIDENCE INVERSION...WHICH SHOULD KEEP LOW CLOUDS IN THROUGHOUT THE DAY. RIGHT NOW ENDED THE DZ/FZDZ MONDAY MORNING...BUT WITH THE LOW CLOUDS THE LIGHT PCPN COULD LINGER. MONDAY NIGHT INTO TUESDAY SEES A SPLIT LEVEL FLOW DEVELOP WITH A NRN STREAM VORT PIVOTING INTO THRU THE OHIO VALLEY LATE MONDAY NIGHT INTO TUESDAY. MODELS PRODUCE AN RIBBON OF SNOW ALONG THE LEADING EDGE OF THE ARCTIC AIR...WITH THE NAM THE QUICKEST AS IT PUSHES THE SNOW IN MONDAY NIGHT. THE GFS AND ECMWF WAIT UNTIL TUESDAY TO BRING THIS FEATURE IN. WILL LEAN TOWARD THE GFS/ECMWF SOLUTION AND WILL KEEP A MENTION OF SNOW ACRS SE HALF OF FA TUESDAY. HIGHS MONDAY AND TUESDAY WILL REMAIN MUCH BELOW NORMAL. ON MONDAY THEY WILL BE IN THE UPPER 20S IN THE NW TO THE MID 30S IN THE SE. THEN ON TUESDAY WITH THE WEATHER SYSTEM WORKING THROUGH HIGHS WILL ONLY REACH THE LOWE 20S IN THE N AND THE LOWER 30S IN THE S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY WEDNESDAY WITH WEAK SYSTEM DROPPING THRU THE GREAT LAKES. THE FAVORABLE MSTR/LIFT TO STAY TO OUR NORTH...SO HAVE MAINTAINED A DRY FCST WED. COLD TEMPERATURES TO PERSIST WITH LOWS AROUND 10 DEGREES WEST TO 15 DEGREES SE AND HIGHS LOWER/MIDDLE 20S NW TO THE LOWER 30S SE. SFC HIGH PRESSURE TO BUILD ACRS THE REGION THURSDAY/FRIDAY TIME FRAME. COLD TEMPERATURES TO CONTINUE THURSDAY WITH MORNING LOWS FROM SINGLE DIGITS OVER THE WEST WHERE SNOW COVER EXISTS TO NEAR 15 SE. HIGHS TO RANGE FROM THE LOWER 20S NW TO NEAR 30 SE. SOME MODERATION TO TEMPERATURES EXPECTED FRIDAY ON BACK SIDE OF SFC HIGH PRESSURE WITH HIGHS FROM LOWER 30S NW TO THE UPPER 30S SE. MID LEVEL FLOW BACKS WITH SYSTEM EXPECTED TO DEVELOP ALONG THE EASTERN SEABOARD LATE FRIDAY INTO SATURDAY. ILN FA IS ON THE FAR NW FRINGE OF THIS SYSTEM AND HAVE LIMITED ANY MENTION OF PRECIP TO A SLIGHT CHC OF A SNOW SHOWER IN THE FAR SE LATE FRIDAY NIGHT INTO SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... STRONGEST WAA ASSOCIATED WITH UPPER LEVEL JET ENERGY WAS PIVOTING NE OUT OF THE TAF REGION THIS AFTERNOON. A MIXTURE OF LIGHT SNOW...SLEET AND FREEZING RAIN WILL TRANSITION OVER TO SOME PATCHY LIGHT FREEZING RAIN OR LIGHT FREEZING DRIZZLE AS DEEP MOISTURE GETS REPLACED WITH LOW LEVEL MOISTURE...WICH WILL LACK ICE NUCLEATION FOR SNOW DEVELOPMENT. FOR TONIGHT...A FRONTAL BOUNDARY WILL APPROACH THE REGION FROM THE WEST AND WILL PUSH ACROSS THE TAF SITES LATE TONIGHT INTO MONDAY. CONTINUED MOIST LOW LEVEL WAA AHEAD OF THE FRONT WILL RESULT IN LOW CEILINGS AND VISIBILITIES...ALONG WITH SOME LIGHT FREEZING RAIN/LIGHT FREEZING DRIZZLE OR IN THE LIQUID FORM AT SOME POINT (KCMH/KLCK) BEFORE THE FRONT PUSHES BY. KEPT VISIBILITIES AS LOW AS 1SM BUT WOULD NOT BE SURPRISED IF SOME POCKETS OF 1/2SM OR LESS DEVELOP. ONCE THE FRONT MOVES THROUGH...DRIER AIR IN THE LOWER LEVELS WILL RESULT IN A SLOW IMPROVEMENT IN VISIBILITIES AND CEILINGS ON MONDAY...WITH MVFR CEILINGS AT LEAST CONTINUING INTO THE AFTERNOON HOURS. OUTLOOK...MVFR CEILINGS TO LINGER INTO MONDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR OHZ045-046- 051>056-060>065-070>074-077>082-088. KY...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HICKMAN/SITES SHORT TERM...SITES LONG TERM...AR AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1200 PM CST SUN DEC 8 2013 .DISCUSSION... SEE AVIATION FOR 18Z TAF ISSUANCE. && .AVIATION... MOSTLY MVFR CIGS TOWARDS THE SOUTH WITH IFR CONDITIONS IN OUR NORTHWESTERN PARTS OF THE CWA. NAM AND RAP ADVERTISING CLEARING FOR KCLL...KUTS...AND POSSIBLY KCXO TONIGHT WHILE GFS AND ECMWF HOLD UP THE CLEARING LINE. LOOKS LIKELY THAT SOME DRY AIR WILL WORK IN FROM THE WEST BUT SHOULD ONLY PUNCH FAR ENOUGH SOUTH TO CLEAR OUT MOST CLOUDS AT KCLL. SINCE NAM IS CLEARING OUT THE CLOUDS IT ALSO SUPPORTS THE FORMATION OF FOG TO THE NORTHERN TAF SITES. THIS IS SUPPORTED BY THE NAM DEWPOINT DEPRESSION FIELD. LIGHT WINDS FROM THE SURFACE HIGH PRESSURE WILL ALSO HELP PROMOTE FOG IN THE NORTHERN TAF SITES. STRONGER WINDS FURTHER SOUTHWARDS IN COMBINATION WITH CLOUD COVER SHOULD KEEP IT MOSTLY A STRATUS EVENT. 23 && .PREV DISCUSSION... /ISSUED 1028 AM CST SUN DEC 8 2013/ DISCUSSION... TEMPERATURES HAVE FINALLY CREPT ABOVE FREEZING NOW ALL ZONES WITH THE FREEZING LINE NOW JUST NORTHWEST OF OUR FORECAST AREA. SOME SPOTS FROM CENTERVILLE OUT TOWARD METROPLEX STILL SEEING FREEZING FOG BUT NOT EXPECTING ANY MORE ICY CONDITIONS IN THOSE NORTHWEST COUNTIES WHICH HAD THE ISSUES LAST NIGHT AND EARLY THIS MORNING. THEREFORE FREEZING FOG ADVISORY WILL BE ALLOWED TO EXPIRE. GOING FORWARD...TRICKY TEMP FORECAST TODAY AS VISIBLE SATELLITE SHOWING A FEW THIN SPOTS. AM FORECASTING HIGH TEMPERATURES A FEW DEGREES BELOW MOST GUIDANCE BASED ON THE IDEA WILL KEEP CLOUD COVER THROUGH THE AFTERNOON...WITH JUST BRIEF PERIODS OF BRIGHTENING FROM SOME FILTERED SUN. AMOUNT OF SUN WILL DETERMINE HIGH TEMPS...SO IF MORE THAN EXPECTED COULD EXCEED FORECAST TEMPS...BUT DONT THINK THAT WILL HAPPEN. WITH SIMILAR VERTICAL MOISTURE PROFILE...COULD STILL SEE SOME SPOTTY DRIZZLE OR SPRINKLES TODAY AS WEAK DISTRUBANCES RIPPLE ALONG IN FAST WSW FLOW ALOFT...BUT CHANCE OF MEASURABLE RAIN ONLY 20 PERCENT OR SO. PREV DISCUSSION... /ISSUED 438 AM CST SUN DEC 8 2013/ DISCUSSION... WENT AHEAD AND REPLACED WINTER WX ADVISORY WITH A FREEZING FOG ADVISORY AND EXTENDED IT UNTIL 10 AM. FIRST ONE I`VE ISSUED IN 19 YEARS HERE...BUT SEEMS TO FIT/DESCRIBE ONGOING CONDITIONS BEST. MODELS HAVE BEEN OVERDOING QPF AMOUNTS/COVERAGE AND FEEL THEY PROBABLY WILL AGAIN TODAY ESP AS RRQ OF JET SHOULD LIFT OUTS OF THE REGION. MAY STILL SEE A PATCHY AREA OF SPRINKLES/DRIZZLE ACROSS SE PARTS THIS AFTN BUT WENT AHEAD AND LOWERED POPS TO ~20%. REINFORCING FRONT STILL PENCILED IN TO MOVE THRU THE REGION ON MONDAY. ANOTHER ROUND OF ISENTROPIC LIFT FROM LATE AFTN MON-LATE TUE MORNING MAY BRING SOME MORE POCKETS OF DZ/-RA. WILL AGAIN NEED TO KEEP AN EYE ON SFC TEMP PROFILE ACROSS OUR EXTREME NRN COUNTIES DURING THIS TIME FRAME BUT FREEZING LINE DOESN`T LOOK TO MAKE IT NEARLY AS FAR SOUTH AS THE PAST FEW. P/MCLDY...COOL...MDRY DAYS SHOULD THEN PERSIST WED-THURS. COMBINATION OF COASTAL TROF AND SHORTWAVES EMBEDDED IN THE SW FLOW ALOFT SHOULD BRING INCREASED RAIN CHANCES THURS NIGHT AND INTO THE WEEKEND. 47 MARINE... LIGHT TO MODERATE OFFSHORE WINDS TO PREVAIL TODAY WITH HIGH PRESSURE SETTLING OVER THE STATE. MODELS STILL GOING WITH THE PASSAGE OF A RE- INFORCING COLD FRONT LATE TOMORROW. WINDS SHOULD PICK BACK UP TO SCA AND/OR SCEC CRITERIA STARTING BY LATE MON NIGHT/TUES. THESE ELEVATED WINDS/SEAS FCST TO PERSIST THROUGH WEDS (OR SO). THE STRONG SFC HIGH IN THE WAKE OF THIS COLD AIRMASS IS NOT EXPECTED TO MOVE EAST OF THE REGION UNTIL THE LATTER PART OF THE WEEK. AS SUCH WE MAY NOT SEE THE RETURN OF ONSHORE WINDS UNTIL SAT. 41 AVIATION... CIGS/VIS FALLING THIS MORNING WITH THE END OF THIS PCPN. WET GROUNDS AND NEARLY CALM WINDS TO HELP IN THE FORMATION OF LOW CLOUDS/FZFG ON THROUGH MID/LATE MORNING. HOWEVER STILL THINKING THAT MVFR CIGS WILL PREVAIL BY THIS AFTN. CIGS/VIS COULD FALL AGAIN TONIGHT ALONG WITH A RETURN OF LIGHT PCPN GIVEN THE PERSISTENT SWLY UPPER FLOW (AND POSSI- BILITY OF ADDITIONAL EMBEDDED SHORTWAVES MOVING ACROSS). REINFORCING SHOT OF COLD AIR EXPECTED MON NIGHT WITH WINDS INCREASING ONCE AGAIN INTO TUES. 41 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 42 36 47 34 42 / 10 10 30 30 20 HOUSTON (IAH) 44 42 53 40 44 / 10 20 30 30 20 GALVESTON (GLS) 49 47 55 46 50 / 20 20 30 30 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...99 AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1254 PM EST SUN DEC 8 2013 .SYNOPSIS... ARCTIC HIGH PRESSURE TO OUR NORTH WILL PROVIDE A CONTINUOUS SOURCE OF COLD AIR TODAY. A TROUGH OF LOW PRESSURE DEVELOPING OVER THE TENNESSEE RIVER VALLEY WILL PROVIDE A CONTINUOUS SOURCE OF MOISTURE. THE COLD AIR WILL INTERACT WITH MOISTURE FOR A BLEND OF WINTRY PRECIPITATION ACROSS THE REGION TODAY AND TONIGHT. FREEZING RAIN WILL BE THE DOMINANT PRECIPITATION TYPE. && .NEAR TERM /THROUGH TONIGHT/... AS 1232 PM EST SUNDAY... ADDED SOME FREEZING DRIZZLE AND FOG TO ISC GRIDS FOR THIS AFTERNOON INTO TONIGHT. TEMPERATURES CONTINUE TO DROP AS A WEDGE OF COLD AIR PUSHES DOWN THE APPALACHIANS. WINTER MIX OF SNOW...SLEET AND FREEZING DRIZZLE AND FREEZING RAIN WILL TRANSITION TO FREEZING RAIN/RAIN FOR MOST OF THE FORECAST TONIGHT. LATEST RADAR TRENDS LINE UP NICELY WITH HRRR SOLUTION FOR THIS AFTERNOON. ADJUSTED TEMPERATURES...WEATHER...POPS AND AMOUNTS FOR THE NEXT COUPLE OF HOURS. AS OF 944 AM EST SUNDAY... WINTER STORM WARNINGS REMAIN IN EFFECT INTO MONDAY MORNING FOR MOST OF CWA WITH A COMPLEX WINTER STORM MARCHING ACROSS OUR REGION TODAY WITH A MIXTURE OF SNOW...SLEET...FREEZING RAIN AND RAIN. TROUGH OF LOW PRESSURE OVER THE TENNESSEE RIVER VALLEY WILL STRENGTHEN THIS AFTERNOON...PROVIDING A CONTINUOUS SOURCE OF MOISTURE. HIGH PRESSURE LOCATED ACROSS PENNSYLVANIA IS BUILDING INTO THE AREA FROM THE NORTH...PROVIDING A SOURCE OF COLD AIR. THE WEDGE OF COLD AIR ON THE EAST SIDE OF THE MOUNTAINS WILL LIKELY REMAIN IN PLACE THROUGH TONIGHT. SNOW AND SLEET REPORTED ACROSS THE NORTH GENERALLY SOUTHEAST WEST VIRGINIA AND ALLEGHANY HIGHLANDS. POCKETS OF SLEET AND FREEZING RAIN FALLING ACROSS LARGE PORTION OF CWA THIS MORNING. REPORTS OF UP TO A TENTH OF AN INCH OF ICE THIS MORNING. RAIN AND EVEN ELEVATED CONVECTION REPORTED THIS MORNING ACROSS THE SOUTH. STILL LOOKS LIKE MOST OF THE REGION WILL TRANSITION TO FREEZING RAIN THIS AFTERNOON INTO TONIGHT. HIGHEST ICE AMOUNTS EXPECTED ALONG THE SOUTHERN BLUE RIDGE. UPDATED ISC GRIDS TO MATCH UP WITH CURRENT WEATHER...TEMPERATURES AND RADAR IMAGES. MORE ADJUSTMENTS LATER THIS MORNING.... WE WILL BE LAUNCHING A 18Z SOUNDING. AS OF 500 AM EST SUNDAY... ALL INGREDIENTS ARE IN PLACE FOR WINTRY PRECIPITATION TODAY. SURFACE HIGH PRESSURE IS STILL BUILDING INTO THE AREA FROM THE NORTHEAST. THIS WILL PROVIDE A CONTINUOUS SOURCE OF COLD AIR TODAY...TEMPERATURES CONTINUING TO FALL THROUGH THE MORNING HOURS. MOST LOCATIONS SHOULD WETBULB AT OR BELOW FREEZING THIS MORNING. SOME AREAS ARE ALREADY WELL BELOW FREEZING...NOTING THE 21 DEG F TEMP AT HSP AIRPORT AS OF 5AM. TROUGH OF LOW PRESSURE OVER THE TENNESSEE RIVER VALLEY WILL STRENGTHEN TODAY...PROVIDING A CONTINUOUS SOURCE OF MOISTURE. ALL MODELS INDICATE STRONG ISENTROPIC LIFT ACROSS THE AREA WITH INCREASING MID LEVEL FRONTOGENESIS. THIS SHOULD YIELD WIDESPREAD DEVELOPMENT OF PRECIPITATION...QPF OF A QUARTER TO THREE QUARTERS OF AN INCH...FROM 12Z/7AM THIS MORNING THROUGH 12Z/7AM MONDAY MORNING. THIS WILL TRANSLATE INTO AN ACCUMULATION OF SIGNIFICANT WINTRY PRECIPITATION...THE DOMINANT P-TYPE...FREEZING RAIN. WARM INTRUSION ALOFT CAPS THE COLD BOUNDARY LAYER. VERY WARM AIR...4-8 DEG C...IS MOVING NORTHEAST THROUGH THE TENNESSEE VALLEY AND WILL FLOW UP AND OVERTOP THE COLD AIR WEDGE HERE ON THE EAST SIDE OF THE APPALACHIAN MOUNTAINS. THIS SHOULD ENSURE THAT MOST... IF NOT ALL...HYDROMETEORS MELT ON THERE WAY TO THE SURFACE. THE ONLY AREA WHERE THE SOUNDING PROFILE MAY ENTERTAIN ISOTHERMAL CHARACTERISTICS...THE WARM NOSE CLOSER TO 0 DEG C...IS FROM THE HIGHLANDS OF VA/WV NORTHEASTWARD INTO THE SHENANDOAH VALLEY. AS SUCH...THE PRECIPITATION MAY TAKE ON THE FORM OF SLEET AND SNOW WHICH COULD ACCUMULATE AN INCH OR TWO THIS MORNING. BY AFTERNOON...THE WARM INTRUSION SHOULD MAKE ITS WAY FAR ENOUGH NORTH LATITUDE TO CHANGE THE PRECIP TO FREEZING RAIN THERE TOO. THE WEDGE OF COLD AIR ON THE EAST SIDE OF THE MOUNTAINS WILL LIKELY REMAIN IN PLACE THROUGH TONIGHT. GIVEN THE EXTENT OF WARMING WHICH IS FORECAST TO TAKE PLACE ALOFT...SOME OF THE MODELS INDICATING AS WARM AS +10 DEG C AT 85H...MODIFICATION OF THE COLD BOUNDARY LAYER SEEMS INEVITABLE...AND SHOULD RESULTING IN STEADILY RISING TEMPERATURES AT THE SURFACE. A GRADUAL CHANGE FROM FREEZING RAIN TO JUST PLAIN OL RAIN IS ANTICIPATED...ESP WEST OF THE APPALACHIAN DIVIDE. WITH THE INCREASED WARMING ALOFT...FOG WILL LIKELY BECOME AN ISSUE AS THE WARMER AIR MIXES WITH THE COLD MOIST BOUNDARY LAYER. GREATEST ACCUMULATIONS OF ICE TODAY/TONIGHT ARE EXPECTED ALONG THE SPINE OF THE BLUE RIDGE WHICH WILL RESIDE IN THE COLDER AIR THE LONGEST...AND WHERE THE LOW LEVEL UPSLOPE EASTERLY WIND FLOW WILL ENHANCE THE LOCAL QPF/ICING AMOUNTS. HIGHEST IMPACT FROM THIS EVENT WILL BE ICING ON ELEVATED SURFACES. THE GROUND IS STILL RELATIVELY WARM FROM THIS PAST WEEKS WARMTH...SO THEORETICALLY THERE SHOULD BE LESS OF AN IMPACT TO ROAD SURFACES. THAT BEING SAID...ITS STILL A GOOD DAY TO SIT THIS ONE OUT. THE ROADS CAN FOOL YOU ONCE THE AIR TEMP REMAINS BELOW FREEZING LONG ENOUGH. UNTREATED SURFACES MAY LOOK WET...BUT MAY ACTUALLY CONTAIN A THIN COATING OF ICE HIDDEN BY WHAT APPEARS TO BE JUST WET PAVEMENT. IF VENTURING OUT OF DOORS...PREP ACCORDINGLY. A COLD RAIN OR FREEZING RAIN MAKES FOR IDEAL HYPOTHERMIC CONDITIONS. WALKING OUT TO CHECK THE ICE ACCUMULATION ON MY VEHICLE WAS ENOUGH TO MAKE MY TEETH CHATTER...AS THE OLD SAYING GOES...THE DAMPNESS IN THE AIR WILL CUT RIGHT THROUGH YA...A COLD RAW RAIN. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 500 AM EST SUNDAY... FOR THE MONDAY MORNING COMMUTE...MAY SEE A FEW POCKETS OF FREEZING RAIN LEFT OVER ACROSS THE SHENANDOAH VALLEY...BUT OTHERWISE EXPECT TEMPERATURES TO BE WARM ENOUGH ALL OTHER LOCATIONS FOR PRECIPITATION TO FALL AS LIQUID. ANY ICING LEFTOVER FROM THE OVERNIGHT SHOULD MELT QUICKLY DURING LATE MORNING AS TEMPERATURES CLIMB INTO THE MID 40S NORTH OF INTERSTATE 81...AND INTO THE LOW 50S FURTHER SOUTH. DURING MID AFTERNOON...EXPECT RAIN TO BECOME MORE SHOWERY IN NATURE AS A COLD FRONT MAKES ITS WAY EAST ACROSS THE AREA. AS WINDS SHIFT NORTHWESTERLY BEHIND THE FRONT...WILL SEE SHOWERS DIMINISH IN COVERAGE FOR THE EVENING...ALTHOUGH THE BREAK WILL BE SHORT-LIVED. PACIFIC HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT MONDAY NIGHT...AND WILL BUILD SOUTHWARD AGAINST THE EASTERN FACE OF THE APPALACHIANS BUY TUESDAY MORNING...RESULTING IN A COOL NORTHEASTERLY WINDFLOW ACROSS THE AREA. MEANWHILE...OUR NEXT UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS...DRAWING ANOTHER WAVE OF WARM GULF MOISTURE NORTHWARD ALONG THE APPALACHIAN CHAIN. RAIN ASSOCIATED WITH THE TROUGH WILL COVER MUCH OF THE AREA DURING THE MORNING...BUT DO NOT ANTICIPATE WIDESPREAD WINTRY PRECIPITATION ISSUES AS THE PACIFIC HIGH PRESSURE SYSTEM HUGGING THE SURFACE WILL BE WARMER THAN THE HIGH WHICH CONTRIBUTED TO FREEZING PRECIPITATION THIS PAST WEEKEND. REGARDLESS...EXPECT TEMPERATURES TO REBOUND LITTLE...IF ANY...FROM OVERNIGHT LOWS DUE TO THE RAIN...WITH AFTERNOON HIGHS RANGING FROM AROUND FREEZING IN SOUTHEAST WEST VIRGINIA...TO THE LOW 40S ACROSS NORTHERN NORTH CAROLINA. THE UPPER LEVEL TROUGH WILL PASS EAST OF OUR AREA TUESDAY NIGHT... TAKING REMAINING PRECIPITATION WITH IT FOR THE MOST PART...ALTHOUGH A FEW UPSLOPE SNOW SHOWERS MAY LINGER ACROSS SOUTHEAST WEST VIRGINIA INTO LATE EVENING. HIGH PRESSURE WILL BUILD IN FROM THE WEST... BRINGING A RETURN OF SOME SUNSHINE FOR WEDNESDAY. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 310 PM EST SATURDAY... SURFACE HIGH PRESSURE REMAINS OVER MUCH OF THE EASTERN UNITED STATES THURSDAY AND FRIDAY WHICH WILL KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL. WEAK NORTHERN STREAM SHORTWAVE COMING THROUGH EARLY THURSDAY...BUT MODELS KEEP FORECAST AREA DRY. NEXT ORGANIZED SYSTEM COMES OUT OF SOUTHERN STREAM FRIDAY NIGHT THROUGH SATURDAY. THIS TIMING LEANS TOWARD SLOWER ECMWF. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 1254 PM EST SUNDAY... ICE AND LOW CEILINGS WILL HINDER AVIATION OPERATIONS THIS AFTERNOON INTO MONDAY. VERY HIGH CONFIDENCE FOR SEVERE CLEAR ICING AT ALL TAF SITES TODAY...WITH ONE QUARTER TO ONE HALF INCH ICE ACCUMULATIONS POSSIBLE. WINTRY MIXTURE OF SNOW...SLEET...FREEZING DRIZZLE AND FREEZING RAIN WILL CONTINUE INTO THIS EVENING...THEN PRECIPIATION WILL BECOME FREEZING RAIN AND RAIN TONIGHT INTO MONDAY MORNING. ACROSS THE NORTH...WHERE COLDER AIR IN PLACE CLOSER TO LWB...SNOW/ICE PELLETS WILL TRANSITION TO FREEZING RAIN. IFR CONDITIONS ARE EXPECTED WITH THE WINTER PRECIPITATION AT THE TAF SITES. EXPECT ALL AIRPORTS TO EXPERIENCE CEILINGS IN THE 300 TO 700 FOOT RANGE THIS AFTERNOON...WITH THESE LOW CEILINGS EXPECTED TO LAST INTO MONDAY. VISIBILITIES WILL ALSO BE UP AND DOWN AS HEAVIER PRECIPITATION MOVES ON AND OFF STATION. WARMER AIR WILL BUILD INTO THE AREA TONIGHT...RAISING SURFACE TEMPERATURES AND ENDING SEVERE CLEAR ICING FROM SOUTHWEST TO NORTHEAST. SUBFREEZING AIR WILL LINGER LONGEST AT LYH...WHICH MAY NOT SEE FREEZING PRECIPITATION END UNTIL 09/12Z TO 09/14Z. MEDIUM TO HIGH CONFIDENCE ON CEILINGS AND VISIBILITIES. HIGH CONFIDENCE IN WINDS DURING THE TAF PERIOD. .AVIATION EXTENDED... WEATHER WILL BE QUITE UNSETTLED THROUGH THE FIRST PART OF THE WEEK. A COLD FRONT WILL MOVE THROUGH ON MONDAY...BRINGING IMPROVED FLYING CONDITIONS AND A SHORT BREAK IN PRECIPITATION AS HIGH PRESSURE BUILDS IN FROM THE WEST. RAIN...IN ADDITION TO MVFR/IFR... WILL RETURN MONDAY NIGHT THROUGH TUESDAY MORNING AS AN UPPER TROUGH MOVES ACROSS THE REGION. HIGH PRESSURE WILL BUILD IN FOR WEDNESDAY AND THURSDAY WITH A RETURN TO VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER STORM WARNING UNTIL 9 AM EST MONDAY FOR VAZ011-013-014- 017>020-022>024-033>035-045>047. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ010-012- 015-016. WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR VAZ032-043-044- 058-059. FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007- 009. NC...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-002- 018. WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR NCZ003>006-019- 020. WV...WINTER STORM WARNING UNTIL 9 AM EST MONDAY FOR WVZ043>045. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ042. && $$ SYNOPSIS...PM NEAR TERM...KK/PM SHORT TERM...NF LONG TERM...AMS AVIATION...KK/NF
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY ISSUED AT 232 PM CST SUN DEC 8 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ONE SHORTWAVE TROUGH MOVING INTO SOUTHWEST WISCONSIN THIS AFTERNOON...WHILE ANOTHER WAVE NOW ENTERING THE CENTRAL GREAT PLAINS. AHEAD OF THE FORMER SHORTWAVE...WEAK ISENTROPIC ASCENT IS PRODUCING A WIDESPREAD SWATH OF LIGHT SNOW ACROSS THE STATE. THE BETTER SNOWS WITH THE FIRST WAVE ARE STILL ACROSS IOWA AT THE MOMENT...WHERE VSBYS ARE DOWN TO A HALF MILE AND WIDESPREAD 1-2 INCHES ARE BEING REPORTED SO FAR. FURTHER CONCERNS RESIDE ALONG THE LAKE SHORE WHERE LAKE ENHANCEMENT IS OCCURRING OVER CENTRAL AND SOUTHERN PARTS OF THE LAKE MICHIGAN SHORELINE. EARLIER REPORTS SHOWED 1-1.5 INCH PER HOUR SNOWFALL RATES IN THOSE LAKE ENHANCED BANDS. ONE OF THESE BANDS IS APPROACHING MANITOWOC...BUT APPEARS TRANSIENT IN A LOW LEVEL CONVERGENT ZONE. LOW LEVEL WINDS ARE JUST STARTING TO TURN TO THE SOUTHEAST SO WILL NEED TO WATCH THESE TRENDS FOR THE REST OF THE AFTERNOON. AS THE SHORTWAVES MOVE ACROSS THE ARE TONIGHT...SNOWFALL AMOUNTS AND IMPACTS ARE THE MAIN FORECAST CONCERN. TONIGHT...SHORTWAVE TROUGH OVER COLORADO WILL QUICKLY EJECT NORTHEAST A DRIVE A STRENGTHENING...ALTHOUGH STILL RELATIVELY WEAK...AREA OF LOW PRESSURE FROM THE CENTRAL GREAT PLAINS AND ACROSS SOUTHEAST WISCONSIN TONIGHT. FORCING AHEAD OF THE SHORTWAVE IN THE FORM OF -DIVQ...UPPER DIVERGENCE...AND ISENTROPIC ASCENT IS ONLY MODEST...BUT BUFKIT SOUNDINGS FROM THE NAM/GFS/SREF ALL INDICATE A 150-200MB DEEP DENDRITIC GROWTH ZONE BETWEEN APPROX 850-650MB OVER CENTRAL AND NORTHEAST WISCONSIN. THIS SUGGESTS THAT WHATEVER WEAK TO MODERATE LIFT THAT OCCURS...SNOW FLAKE PRODUCTION WILL BE VERY EFFICIENT AND SNOW TO LIQUID RATIOS WILL BE QUITE HIGH. GENERALLY WENT WITH A 19-20:1 RATIO...ALTHOUGH A LITTLE LOWER NEAR THE LAKE MICHIGAN SHORELINE WHERE ONSHORE FLOW WILL LEAD TO SLIGHTLY WARMER LOW LEVEL THERMAL PROFILES. THE BULK OF THE SNOW LOOKS TO OCCUR IN A COUPLE WAVES. THE FIRST WILL ARRIVE LATE THIS AFTERNOON INTO EARLY THIS EVENING FROM THE FIRST AREA OF SNOW OVER IOWA AND SE MINNESOTA...FOLLOW BY THE MAIN SHORTWAVE AND SURFACE LOW OVER COLORADO. PLENTY OF 1-3" INCH REPORTS UPSTREAM OVER IOWA...AND FEW 4-6 INCH REPORTS OVER EASTERN NEBRASKA AS WELL. WILL INCREASE AMOUNTS A LITTLE OVER N-C WISCONSIN TO AROUND 3 INCHES. THE PRIMARY CONCERN THOUGH WILL BE ALONG THE LAKE SHORE WHERE WINDS WILL BE TURNING TO THE EAST AND SOUTHEAST THIS EVENING. THE LAKE ENHANCEMENT OVER SOUTHEAST WISCONSIN APPEARS TO BE FLUCTUATING...AS A CONVERGENT BAND LIFTS NORTH. BUT EARLIER SNOWFALL RATES WHERE ENHANCEMENT TOOK PLACE ARE ALARMING. LOOKS LIKE A GOOD 9-12 HOURS OF ENHANCEMENT POSSIBLE OVER NORTHEAST WISCONSIN. WILL GO WITH WIDESPREAD 2-4 INCHES EXCEPT NEAR THE LAKESHORE WHERE 5-6 INCHES WILL BE POSSIBLE. HEADLINES WILL REMAIN THE SAME...AND WILL PASS ALONG LAKE ENHANCEMENT CONCERNS TO THE EVENING SHIFT. MONDAY...THE SNOW WILL BE ENDING EARLY MONDAY MORNING OVER NORTHEAST WISCONSIN AS THE SURFACE LOW PULLS AWAY. WEST WINDS WILL BE STRENGTHENING IN THE WAKE OF THE LOW AND COLD ADVECTING AT THE SAME TIME. TEMPS WILL REMAIN NEARLY STEADY OR FALL SLIGHTLY DURING THE DAY...DESPITE CLEARING TAKING PLACE. WITH WINDS GUSTING TO 30 MPH...APPARENT TEMPS WILL BE FALLING TO NEAR 20 BELOW ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. WILL LIKELY NEED WIND CHILL HEADLINES...BUT WITH THE ONGOING SNOW ADVISORY...WILL NOT ISSUE ANOTHER HEADLINE. MORNING TO MIDDAY HIGHS IN THE MIDDLE SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR THE LAKE SHORE. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 232 PM CST SUN DEC 8 2013 VERY COLD AIR WILL REMAIN FIRMLY ENTRENCHED ACROSS THE AREA MONDAY NIGHT. EXPECT WINDS CHILLS TO DROP TO AROUND 25 BELOW ACROSS THE NORTH. HOWEVER...TEMPERATURES ARE EXPECTED TO MODIFY SOME LATE MONDAY NIGHT DUE TO INCREASING CLOUDINESS AND AHEAD OF APPROACHING SYSTEM. INCREASED CHANCES OF SNOW ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. INCREASED SNOW CHANCES SIGNIFICANTLY ON TUESDAY MORNING AS SYSTEM MOVES ACROSS THE AREA. ALSO...PRECIPITATION TOTALS WILL BE LIGHT...SNOW RATIOS WOULD SUGGEST LESS THAN AN INCH OF NEW SNOW TUESDAY MORNING. THE HIGHEST SNOWFALL TOTALS WILL BE ACROSS THE NORTH. MOST OF THE MODELS NOW BRING CLIPPER SYSTEM SOUTH OF THE AREA TUESDAY NIGHT. THE ONLY EXCEPTION WAS THE ECMWF...THUS WILL CONTINUE CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE GFS MODELS HAS BEEN WAFFLING ON NORTHWARD EXTENT OF THE PRECIPITATION FIELD. VERY COLD AIR IS EXPECTED WEDNESDAY MORNING. ANOTHER SYSTEM EXPECTED TO PASS ACROSS THE NORTH THURSDAY/THURSDAY NIGHT. LOW CONFIDENCE ON WHEN THIS SYSTEM WOULD BRING A SMALL CHANCE OF LIGHT SNOW DURING THIS PERIOD. CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST THURSDAY NIGHT...BUT LATER SHIFTS MAY NEED TO SPEED UP THE SNOW AND ADD A CHANCE TO THE THURSDAY PERIOD. THE ARCTIC AIR WILL MODIFY FRIDAY INTO NEXT WEEKEND WITH HIGHS IN THE UPPER TEENS TO MIDDLE 20S. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1131 AM CST SUN DEC 8 2013 LOW PRESSURE WILL MOVE NORTHEAST THIS AFTERNOON ACROSS THE PLAINS AND THE CENTRAL GREAT LAKES TONIGHT. AHEAD OF THIS LOW...LIGHT SNOW WILL CONTINUE THIS AFTERNOON WHICH WILL DROP VSBYS TO IFR. THE SNOW WILL INCREASE IN INTENSITY THIS EVENING WHICH WILL DROP VSBYS TO LIFR...MAINLY OVER CENTRAL AND NORTHEAST WISCONSIN. LOCALLY VLIFR IN MODERATE TO HEAVY SNOW IS POSSIBLE ALONG THE LAKE MICHIGAN SHORELINE DUE TO LAKE ENHANCEMENT. THE SNOW WILL GRADUALLY DIMINISH OVERNIGHT TONIGHT...BUT WEST WINDS WILL DEVELOP BEHIND THE SYSTEM AND BECOME GUSTY BY MORNING. THE GUSTY WEST WINDS WILL LIKELY CREATE BLOWING AND DRIFTING OF THE NEW SNOW BY MIDDAY MONDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ005-010-011- 018>021-030-031-035>040-045-048>050-074. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ012-013-022- 073. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......MPC