Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 272046 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 346 PM EST TUE JAN 27 2015 .SYNOPSIS...
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A STRONG COASTAL LOW PRESSURE EAST OF CAPE COD WILL SLOWLY MOVE AWAY FROM THE REGION TONIGHT...WITH AREAS OF SNOW TAPERING OFF TO SCATTERED FLURRIES BY WEDNESDAY MORNING. IN ADDITION...GUSTY NORTH WINDS WILL SLOWLY DECREASE AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. A FAST MOVING CLIPPER LIKE SYSTEM WILL IMPACT THE NORTH COUNTRY LATE THURSDAY INTO FRIDAY WITH ANOTHER ROUND OF LIGHT ACCUMULATING SNOW LIKELY. TEMPERATURES WILL START BELOW NORMAL...BUT WARM TO NEAR NORMAL LEVELS BY THURSDAY.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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AS OF 345 PM EST TUESDAY...AVE CANCELLED WINTER STORM WARNING AND REPLACED WITH WINTER WX ADVISORY FOR SNOW AND BLOWING SNOW. ALSO...EXPANDED ADVISORY TO COVER PARTS OF THE CHAMPLAIN AND WESTERN SLOPES FOR THE COMBINATION SNOW AND BLOWING SNOW THROUGH THE EVENING COMMUTE. EXPECTING A DIFFICULT EVENING COMMUTE ACROSS MOST THE REGION. BTV PICKED UP 3 INCHES OF SNOW IN JUST SEVERAL HRS UNDER THIS BAND OF HEAVY SNOW THIS AFTN. EXPECTING ADDITIONAL ACCUMULATIONS OF 1 TO 3 WITH LOCALIZED HIGHER AMOUNTS UNDER THIS NARROW MESO BAND OF MODERATE SNOW ACRS PORTIONS OF THE CHAMPLAIN AND WESTERN SLOPES. FCST CHALLENGE TONIGHT WL BE AREAL COVERAGE/INTENSITY OF SNOW THRU MIDNIGHT...ESPECIALLY FOR THE CHAMPLAIN VALLEY AND PARTS OF GREEN MTNS. CRNT WATER VAPOR SHOWS DEEP CLOSED CYCLONIC CIRCULATION JUST EAST OF CAPE COD THIS AFTN...WITH SEVERAL BAND OF MID/UPPER LVL MOISTURE ROTATING BACK TOWARD OUR CWA. WATER VAPOR AND RAP SHOWS THIS MID LVL MOISTURE AND ELONGATED 5H VORTICITY MAXIMUM WL BECOME STATIONARY ACRS THE CHAMPLAIN VALLEY/CENTRAL VT THIS AFTN/EVENING...WITH OCCASIONAL SNOW LINGERING THRU THE EVENING HRS. THIS SUPPORT ALOFT...COMBINED WITH FAVORABLE NORTHERLY FLW WL ENHANCE CONVERGENCE ON THE EASTERN SIDE OF THE CHAMPLAIN VALLEY...SUPPORTING LIGHT SNOW THRU 06Z...BEFORE TAPERING OFF TO FLURRIES. IN ADDITION...NAM FROUDE NUMBER SHOWS BLOCKED FLW WITH VALUES <0.50...SUPPORTING ENHANCED SNOWFALL ALONG AND UPSTREAM OF THE GREEN MTNS INTO THE CHAMPLAIN VALLEY. WL TRY TO SHOW THIS DETAIL IN THE GRIDS AND INCREASE THE SNOWFALL AMOUNTS SLIGHTLY ACRS THIS REGION...THINKING BTWN 1 AND 4 INCHES...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. ELSEWHERE...AREAL COVERAGE OF MID LVL MOISTURE DECREASES RAPIDLY THIS AFTN/EVENING...AND ADDITIONAL SNOWFALL WL BE LIMITED. THIS IS ALREADY SUPPORTED BY RADAR SHOWING LARGE HOLE OF NO PRECIP ACRS MOST OF THE CT RIVER VALLEY AND NEK OF VT. ADDITIONAL SNOWFALL WL BE A DUSTING TO AN INCH OR TWO POSSIBLE IN THESE AREAS...WITH ONLY FLURRIES FOR THE SAINT LAWRENCE VALLEY/WESTERN DACKS. ALSO...EXPECT GUSTY NORTH WINDS TO CONTINUE...ESPECIALLY CHAMPLAIN VALLEY WITH SOME ENHANCED CHANNELING...WHICH WL CAUSE AREAS OF BLOWING AND DRIFTING SNOW. GUSTY TO 30 MPH WL BE LIKELY THRU 03Z TONIGHT. TEMPS WL REMAIN NEARLY STEADY IN THE SINGLE DIGITS ABOVE/BLW ZERO TO NEAR 10F MOST LOCATIONS.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
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AS OF 345 PM EST TUESDAY...SFC HIGH PRES BUILDS ACRS OUR CWA ON WEDS...RESULTING IN A SLOW WEST TO EAST CLRING TREND. GFS/ECMWF STILL SHOWS SOME LINGERING 850 TO 500MB RH ACRS OUR CENTRAL/EASTERN CWA THRU 15Z...BEFORE SHIFTING IT EASTWARD. LARGE SCALE SUBSIDENCE AND DEEP DRYING WL RESULT IN CLRING SKIES BY 18Z WEDS. NEXT FAST MOVING CLIPPER LIKE SYSTEM ARRIVES LATE THURS INTO FRIDAY. LATEST GUIDANCE TRACKS THIS SYSTEM ACRS OUR CWA...WHICH WL CAUSE A WIDESPREAD LIGHT SNOW EVENT. EXPECTING AN ADVISORY LVL EVENT WITH GENERAL ACCUMULATIONS OF 3 TO 5 INCHES...EXCEPT SLIGHTLY HIGHER AMOUNTS OF 6 INCHES IN THE FAVORABLE UPSLOPE REGIONS. TEMPS WL REBOUND TO NEAR NORMAL LEVELS AFTER A COLD START ON THURS MORNING.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/...
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AS OF 335 PM EST TUESDAY...AN ACTIVE PATTERN IS QUITE LIKELY FOR THE PERIOD, WITH TWO OPPORTUNITIES FOR SNOW AND SEVERAL DAYS WITH WELL BELOW NORMAL TEMPERATURES. GIVEN THE ONGOING WEATHER, AND FOCUS NEEDED ON THAT, I RELIED RATHER HEAVILY ON A "DOWN THE MIDDLE" MODEL BLEND FOR MOST OF THE FORECAST PERIOD, WITH ONLY A FEW MANUAL MODIFICATIONS. FROM WHAT I SAW, THE 12Z SUITE OF GFS, GFS ENSEMBLE AND ECMWF WERE ALL IN THE BALLPARK ENOUGH THAT A BLEND SHOULD WORK OUT PRETTY GOOD. DAILY DETAILS BELOW... FRIDAY: CLIPPER WILL BE QUICKLY EXITING DURING THE DAY, AND AS IT MOVES EAST OF HERE IT SHOULD STRENGTHEN ONCE IT REACHES THE "WARMER" ATLANTIC OCEAN WATERS. NET RESULT WILL BE AN INCREASE IN NORTHWEST WINDS -- COULD BE GUSTY AT TIMES. PAINTED IN SOME 20-30MPH GUSTS. THESE NORTHWEST WINDS WILL ALSO USHER IN COLDER AIR AS THE DAY GOES ON. DEFINITELY A NON-DIURNAL TEMPERATURE TREND WITH HIGHS FIRST THING. THE MID 20S "WARMTH" AT 8AM WILL END UP IN THE 5-15F RANGE BY EVENING TIME. COULD HAVE SOME WIND CHILL ISSUES TO TRACK COME FRIDAY/FRIDAY NIGHT. ON THE PRECIPITATION SIDE OF THINGS, SNOW SHOWERS FIRST THING IN THE DAY WILL DIMINISH AND BE MORE CONFINED TO THE MOUNTAINS BY AFTERNOON. IN THE END, LOOKS LIKE A SOLID 3-5" "ADVISORY" LEVEL EVENT (LOCALLY A BIT MORE IN THE NORTHERN MOUNTAINS). GENERALLY CLEAR AND COLD FRIDAY NIGHT. SUB- ZERO FOR EVERYBODY! SATURDAY: HIGH PRESSURE BUILDS IN. SHOULD BE SUNNY, BUT ALWAYS BEWARE OF SUNNY DAYS IN MID-WINTER. THAT MEANS COLD TOO. 925MB TEMPERATURES DOWN AROUND -20C. HIGHS 0 TO 8F WHERE WE LIVE. BRRR. WARM WEATHER FANS WILL NEED TO LOOK AT THE SUNNY SKIES AND PRETEND TO FEEL THE WARMTH. SATURDAY NIGHT - ANOTHER QUIET AND COLD NIGHT. SUB-ZERO FOR US ALL AGAIN. SUNDAY/MONDAY: FAST MOVING TROUGH IN THE UPPER FLOW WILL RESULT IN CYCLOGENESIS IN THE OHIO VALLEY SUNDAY, FOLLOWED BY PERHAPS THE DEVELOPMENT BY MONDAY OF A STRONG SURFACE LOW THAT WILL TRACK SOMEWHERE JUST SOUTH OF HERE. GFS SUGGEST JUST SOUTH OF LONG ISLAND. ECMWF IS A BIT FARTHER NORTH AND GOES ACROSS SOUTHERN NEW ENGLAND. HAVE GONE AHEAD AND BUMPED POPS UP TO THE 50-60% RANGE FOR SUNDAY NITE/MONDAY. CERTAINLY STILL A LOT OF UNCERTAINTY WITH REGARD TO TRACK AND INTENSITY. AT THIS POINT LOOKS LIKE AN ALL SNOW EVENT WITH LIKELY A PLOWABLE AMOUNT OF SNOW. HOWEVER, IF THE TRACK ENDS UP GOING A LITTLE FURTHER NORTH, THEN WE MAY BE LOOKING AT SOME MIXED PRECIPITATION ISSUES FOR PARTS OF THE FORECAST AREA. AS MENTIONED, EARLIER, JUST WENT WITH MODEL BLENDS FOR TEMPERATURES BUT ABOVE THE BLENDS FOR PRECIPITATION CHANCES. TUESDAY: ANOTHER SHOT OF BITTER ARCTIC AIR IN THE WAKE OF THE SUNDAY/MONDAY STORM. GFS IS BRUTALLY COLD. 925MB TEMPERATURES DOWN TO -35C! THE RAW MODEL SURFACE TEMPERATURE COME TUESDAY MORNING IS -25 TO -35F! (NOTE THAT MOS TURNS THAT INTO A -3F FOR BTV), AND HIGH TEMPERATURES WOULD ONLY BE -5 TO -15F. THE ECMWF IS "MUCH" WARMER -- 925MB TEMPERATURES OF -20C WITH IT`S RAW SURFACE TEMPERATURES ABOUT -15F IN THE MORNING WITH HIGHS -5 TO +5F. AT THIS POINT, HAVE MADE THE FORECAST CLOSER TO THE ECWMF. I DID WANT TO MAKE THE 7TH DAY OF THE FORECAST TO SHOW A +1C FOR A HIGH TEMPERATURE, JUST TO GIVE SOME HOPE TO WARM WEATHER FANS AFTER DAYS OF SUB-FREEZING (< 0C) HIGHS. BUT ALAS, IT WASN`T POSSIBLE.
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&& .AVIATION /20Z TUESDAY THROUGH SUNDAY/... THROUGH 18Z WEDNESDAY...CONFIDENCE ON THE LOW SIDE FOR SPECIFIC DETAILS IN THE TAFS FOR NOW THROUGH 03Z. JUST WANTED TO GET THAT OUT THERE FIRST. CURRENTLY, CONDITIONS RANGE FROM IFR/LIFR ACROSS MUCH OF VERMONT TO VFR ACROSS MUCH OF NORTHERN NEW YORK. BANDS OF SNOW ARE SLOWLY PUSHING FROM EAST TO WEST ACROSS VERMONT. IN SPOTS, THE SNOW DOES BRIEFLY RESULT IN VISIBILITY REDUCTIONS DOWN TO 1/4SM, BUT IN GENERAL IT`S MORE LIKE 3/4SM TO 1 1/2SM. RADAR TRENDS SHOWING THE INITIAL BATCH OF SNOW IS DRYING UP AS IT MOVES TOWARD NORTHERN NEW YORK. THERE IS UNCERTAINTY AS TO WHETHER IT MAKES IT TO SLK, THOUGH IT APPEARS MSS WILL STAY VFR. RADAR ALSO SHOWING A "BREAK IN THE ACTION" DEVELOPING ACROSS THE VT/NH BORDER. IT COULD BE THAT THIS IS A SIGN THAT THE SNOW WONT LAST ALL THAT LONG (6 HOURS OR SO) IN ANY SPOT. HOWEVER, SOME GUIDANCE SUGGESTS LIGHT SNOW CONTINUES ALL THE WAY TO 12Z. GAVE IT MY BEST SHOT. IN GENERAL GOING WITH THE IDEA THAT THE BULK OF THE MODERATE SNOW & LOWEST VISIBILITIES WILL LAST UP TO 20-23Z OR SO, WITH DIMINSHING SNOW THROUGH 03Z (AND MVFR CONDITIONS). AFTER THAT, VFR SHOULD BE THE RULE. MAY END UP NEEDING TO AMEND FORECASTS IF THE RADAR TRENDS INDICATE THE FORECASTS NEED SOME FIXING. NORTHERLY SURFACE WINDS WILL REMAIN GUSTY, ESPECIALLY IN THE CHAMPLAIN VALLEY. 20-25KTS SHOULD BE COMMON. PERHAPS SOME LOWER 30KT GUSTS. THESE WINDS WILL DIMINISH BY LATE AFTERNOON. THOUGH NOT EXPLICITLY SHOWN IN THE TAFS, MINOR BLOWING SNOW MAY OCCUR AS WELL. FROM 12Z WEDNESDAY ONWARD, LOOKS LIKE VFR CONDITIONS AREA WIDE. OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY... 18Z WEDNESDAY THROUGH 00Z FRIDAY...VFR. 00Z FRIDAY THROUGH 00Z SATURDAY...MVFR/IFR IN PERIODS OF SNOW. 00Z SATURDAY ONWARD...VFR. && .EQUIPMENT... AS OF 122 PM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED NEAR WATERTOWN NEW YORK WILL BE DOWN AT LEAST THROUGH TUESDAY. THIS IS DUE TO A PEDESTAL DYNAMIC FAULT. ELECTRONICS TECHNICIANS HAVE ORDERED NEW PARTS TO FIX THIS PROBLEM. HOWEVER...THE NEW PARTS HAVE NOT ARRIVED AS OF THIS TIME AND THE KTYX RADAR WILL LIKELY NOT BE RESTORED TO SERVICE UNTIL SOMETIME THIS WEEK. && .BTV WATCHES/WARNINGS/ADVISORIES...
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VT...WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR VTZ002>012-016>019. NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR NYZ035.
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&& $$ SYNOPSIS...TABER NEAR TERM...TABER SHORT TERM...TABER LONG TERM...NASH AVIATION...NASH EQUIPMENT...WFO BTV

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