Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 281425 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 925 AM EST WED JAN 28 2015 .SYNOPSIS... LINGERING FLURRIES WILL END THIS MORNING WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED BY AFTERNOON AS HIGH PRESSURE SLOWLY BUILDS EAST INTO THE REGION. CLEAR AND COLD WEATHER IS EXPECTED TONIGHT WITH THE HIGH OVERHEAD. BY LATER THURSDAY INTO THURSDAY NIGHT...WIDESPREAD LIGHT SNOWS AND MILDER TEMPERATURES RETURN TO THE REGION AS LOW PRESSURE TRACKS EAST FROM THE GREAT LAKES. BEHIND THIS SYSTEM MUCH COLDER AIR RETURNS FOR THE UPCOMING WEEKEND WITH THE POTENTIAL FOR MORE SNOWS BY EARLY NEXT WEEK. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... AS OF 919 AM EST WEDNESDAY...MINOR UPDATE TO CLEAN UP SOME LEFTOVER OVER POPS ACRS THE CHAMPLAIN VALLEY AND ADJUST THE SKY GRIDS FOR LATEST TRENDS ON VIS. CRNT RADAR SHOWS PRECIP HAS ENDED ACROSS THE CHAMPLAIN VALLEY THIS MORNING...WITH CLEARING SKIES DEVELOPING FROM WEST TO EAST ACRS OUR CWA. THIS WL CONT THRU THE AFTN HOURS AS SFC HIGH PRES BUILDS INTO OUR FA. TEMPS WL SLOWLY WARM INTO THE MID/UPPER TEENS MOST LOCATIONS WITH NORTH WINDS AT 5 TO 15 MPH. SOME HIGHER GUSTS POSSIBLE IN AREAS OF ENHANCED CHANNELING ACROSS THE CHAMPLAIN AND SAINT LAWRENCE VALLEYS. PRIOR DISCUSSION FROM 320 AM EST WEDNESDAY... THE STORM SYSTEM WHICH BROUGHT LIGHT ACCUMULATING SNOWS AND GUSTY WINDS TO THE REGION YESTERDAY CONTINUES TO PULL SLOWLY AWAY INTO THE MARITIMES EARLY THIS MORNING. THIS TREND WILL CONTINUE TODAY WITH THE LOW GRADUALLY LOSING INFLUENCE ON AREA WEATHER CONDITIONS...BEING GRADUALLY REPLACED BY HIGH PRESSURE BUILDING EAST FROM THE GREAT LAKES. THUS WINDS SLOWLY ABATE AND ANY LINGERING FLURRIES/LIGHT SHSN WILL COME TO AN END BY AFTERNOON. CLOUDY SKIES THIS MORNING WILL TREND PARTLY TO MOSTLY SUNNY BY DAYS END AS HIGHS TOP OUT GENERALLY IN THE TEENS PER BLENDED MODEL OUTPUT. && .SHORT TERM /7 PM THIS EVENING THROUGH FRIDAY/... AS OF 320 AM EST WEDNESDAY...NARROW RIDGE AXIS THEN BUILDS ATOP THE REGION TONIGHT WITH MAINLY CLEAR SKIES AND LIGHT WINDS. WITH A FRESH SNOW COVER AND LIGHT WINDS IDEAL RADIATIONAL EFFECTS ARE EXPECTED AND I TRENDED ON THE LOWER SIDE OF TEMPERATURE GUIDANCE OFFERING MINIMUMS GENERALLY IN THE -5 TO -15F RANGE. CUSTOMARY VARIABILITY WILL EXIST HOWEVER AND I IMAGINE OUR TYPICAL COLDER LOCALES ACROSS THE ADIRONDACKS INTO NC/NE VT MAY APPROACH -20F BY MORNING. MILDEST IN THE CHAMPLAIN VALLEY...AROUND ZERO GIVE OR TAKE A FEW DEGREES. HIGH PRESSURE THEN EXITS EAST DURING THURSDAY AND IS QUICKLY REPLACED BY QUICK MOVING NORTHERN STREAM ENERGY ADVANCING FROM THE OHIO VALLEY/GREAT LAKES STATES. MODELS HAVE TRENDED SLIGHTLY FURTHER NORTH WITH THIS SYSTEM...TAKING A MEAN SLV TRACK ALONG THE INTL BORDER BY THURSDAY NIGHT INTO FRIDAY. AMPLE WARM THERMAL/MOISTURE ADVECTION ON THE NOSE OF ROBUST LOW TO MID LEVEL JET ENERGY SHOULD ALLOW WIDESPREAD LIGHT SNOWS TO DEVELOP ACROSS OUR REGION TOWARD EVENING AND CONTINUE THURSDAY NIGHT INTO THE FIRST PART OF FRIDAY BEFORE TAPERING BACK. HARD TO PINPOINT EXACT SNOW TOTALS...BUT CURRENT FORECAST TRACK WOULD FAVOR THE HIGHEST AMOUNTS ACROSS THE NORTH/NRN MTS WHERE A PLOWABLE SNOWFALL OF SEVERAL INCHES WILL BE POSSIBLE. THESE TYPES OF CLIPPER-LOW TRACKS GENERALLY FAVOR THE FAR NRN SLV INTO THE MONTREAL AREA FOR THE HEAVIEST TOTALS HOWEVER. IN THIS AREA STRONG FRONTOGENETICAL FORCING WILL OCCUR AS MEAN NORTHEASTERLY PBL FLOW IS INTERSECTED BY STRONG SOUTHWESTERLY FLOW TO THE IMMEDIATE SOUTH. TIME WILL TELL...BUT EARLY MODEL OUTPUT USING MEAN 15:1 SNOW RATIOS (16-17:1 MTS) WOULD SUGGEST AS MUCH SHOWING A GENERAL 3-6 INCH SNOWFALL ACROSS OUR AREA WITH HIGHER TOTALS (FROM 6 TO 8 INCHES OR SO) IN A SW-NE STRIPE ALONG THE ST LAWRENCE RIVER FROM MASSENA THROUGH MONTREAL TOWARD SHERBROOKE. SOME SHADOWING ALSO POSSIBLE IN THE CHAMPLAIN VALLEY IF LOW TRACK VERIFIES. INDEED...CURRENT MODEL OUTPUT SHOWING A ROBUST LOW LEVEL SOUTHERLY JET OF 45 KTS IN THE VALLEY DURING THIS TIME FRAME...BRIDGED ALOFT BY A 50 KT SOUTHWESTERLY 850 MB JET...CLASSIC SHADOWING SIGNATURES. AGAIN...TIME WILL TELL. AT THIS POINT I`VE LEANED TOWARD CHAMPLAIN VALLEY TOTALS IN THE 2-4 INCH RANGE WITH HIGHEST TOTALS TOWARD THE INTL BORDER. IN REGARD TO TEMPERATURES A NON-DIURNAL TREND WILL BE OFFERED WITH HIGH THURSDAY IN THE MID TO UPPER 20S...AND HOLDING NEAR STEADY THURSDAY NIGHT UNDER BROAD SOUTHERLY FLOW. AS SYSTEM PASSES DURING FRIDAY...ASSOCIATED ARCTIC FRONTAL BOUNDARY WILL SWING INTO THE REGION. THUS HIGHS SHOULD OCCUR IN THE MORNING FOR MOST SPOTS...WITH READINGS FALLING STEADILY IN THE AFTERNOON AS STRONG POST-FRONTAL COLD ADVECTION BEGINS ON GUSTY NORTHWEST FLOW. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 302 AM EST WEDNESDAY...DEPARTING CLIPPER LOW WILL CONTINUE TO PRODUCE SOME SNOW SHOWERS ACROSS THE NORTH COUNTRY FRIDAY NIGHT, ESPECIALLY IN THE HIGHER TERRAIN, AS WINDS SHIFT OUT OF THE NORTHWEST RESULTING IN UPSLOPE SNOW. EXPECT THESE SNOW SHOWERS TO END SATURDAY AS THE SURFACE LOW AND ASSOCIATED NEGATIVELY TILTED TROUGH PUSH FURTHER EAST INTO THE CANADIAN MARITIMES. THIS DRY WEATHER WILL PERSIST INTO SUNDAY/SUNDAY NIGHT. 00Z GFS AND ECMWF SHOWING DISAGREEMENT WITH THE NEXT SYSTEMS TRACK AND STRENGTH. SOUTHERN STREAM LOW WILL DEVELOP IN THE MISSISSIPPI VALLEY, MOVING NORTHEAST INTO THE OHIO VALLEY BY SUNDAY NIGHT. GFS LAGGING BEHIND ECMWF TRACK AS ECMWF KEEPS UPPER LEVEL TROUGH MORE POSITIVELY TILTED THROUGH AT LEAST MONDAY. GFS BEGINS NEGATIVE TILTING EARLIER, HENCE THE SLOWER TRACK. BY MONDAY EVENING, AS BOTH MODELS BRING THE SURFACE LOW OVER/NEAR THE COASTAL WATERS, RAPID STRENGTHENING IS DEPICTED. THROUGHOUT THE DEVELOPMENT OF THIS LOW, BOTH MODELS AGREE THAT MOISTURE FEED FROM THE GULF OF MEXICO WILL PERSIST WITH 250MB JET EXCEEDING 125KTS STRETCHES ACROSS THE SOUTHEAST UNITED STATES UP TO THE MID ATLANTIC AND NORTHEAST. SO WHILE DETAILS OF THIS SYSTEM ARE STILL UNCERTAIN, WILL HAVE TO KEEP AN EYE ON IT. AS FOR TEMPERATURES, WE WILL HAVE A VERY COLD START TO THE PERIOD AS 925MB TEMPERATURES FALL TO -20C TO -15C. FRIDAY AND SATURDAY NIGHT MINS WILL RANGE FROM ZERO TO AS LOW AS -18F. SATURDAY WILL REMAIN IN THE SINGLE DIGITS DURING THE DAY. GFS SHOWS SIGNIFICANT WARMING AHEAD OF NEXT WEEKS STORM, WHILE THE FASTER MOVING ECMWF BRINGS IN REINFORCING COLD AIR BY LATE MONDAY. THEREFORE, EXPECT WARMEST DAY TO BE SUNDAY WITH MAXES IN THE TEENS. DEPENDING ON TRACK AND PROGRESSION OF STORM, MONDAY LOOKS TO BE SIMILAR TO SUNDAY BEFORE MUCH COLDER THAN NORMAL TEMPERATURES RETURN FOR MONDAY NIGHT AND TUESDAY. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THROUGH 12Z THURSDAY...VFR WITH A BAND OF SNOW SHOWERS CREATING MVFR CONDITIONS IN THE CHAMPLAIN VALLEY...MAINLY AFFECTING KBTV BRIEFLY. THESE SNOW SHOWERS WILL DIMINISH AROUND 14Z/15Z AND VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD FOR ALL SITES. LOW LEVEL INVERSION WILL KEEP LOW LEVEL MOISTURE IN PLACE FOR THE FIRST HALF OF THE DAY WITH SCT 030-060. DRIER AIR WILL FILTER IN ON NORTH/NORTHWEST FLOW, LEADING TO MOSTLY CLEAR SKIES BY THE AFTERNOON AND LASTING INTO THE OVERNIGHT. NORTH TO NORTHWEST WINDS WILL PERSIST TODAY FOR ALL BUT KSLK/KMSS WHICH WILL SEE SOUTHWEST TO WEST WINDS. SOME GUSTINESS EXPECTED AT KBTV AND KRUT AT 15-25KTS. KPBG/KSLK AND KMPV MAY ALSO SEE A FEW GUSTS. OUTLOOK 12Z THURSDAY THROUGH SUNDAY... 12Z THURSDAY THROUGH 00Z FRIDAY...VFR CONDITIONS UNDER HIGH PRESSURE. 00Z FRIDAY THROUGH 12Z SATURDAY...MVFR/IFR IN PERIODS OF SNOW. 12Z SATURDAY ONWARD...VFR. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG/TABER SHORT TERM...JMG LONG TERM...KGM AVIATION...KGM

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