Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 280530 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1230 AM EST SAT FEB 28 2015 .SYNOPSIS...
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HIGH PRESSURE OVER THE NORTHEASTERN UNITED STATES WILL BRING CONTINUED FAIR WEATHER AND MOSTLY CLEAR SKIES THROUGH MUCH OF THE WEEKEND. AN APPROACHING WAVE OF LOW PRESSURE FROM THE OHIO VALLEY WILL BRING LIGHT SNOW BEGINNING SUNDAY EVENING AND LASTING INTO MONDAY MORNING...WITH SNOW ACCUMULATIONS OF 2 TO 4 INCHES GENERALLY EXPECTED. ANOTHER STRONGER AREA OF LOW PRESSURE IS EXPECTED TO PASS TO OUR WEST TUESDAY NIGHT INTO WEDNESDAY BRINGING MIXED WINTRY PRECIPITATION AND PERIODS OF GUSTY WINDS. FOLLOWING THE BRIEF WARMUP WEDNESDAY...COLDER WEATHER IS EXPECTED TO RETURN FOR THURSDAY AND CONTINUE INTO FRIDAY.
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&& .NEAR TERM /UNTIL 7 AM THIS MORNING/...
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AS OF 1229 AM EST SATURDAY...NO SIGNIFICANT CHANGES FOR 1230 UPDATE...PREVIOUS DISCUSSION FOLLOWS. A FEW ADDITIONAL TWEAKS TO SKY COVER ACROSS THE WESTERN ADIRONDACKS AS OF 900 PM TO ACCOUNT FOR DOWNSTREAM TRANSPORT OF LAKE INDUCED CLOUD COVER. GENERALLY LIGHT BOUNDARY LAYER FLOW SHOULD KEEP ANY FLURRY/SHSN ACTIVITY CONFINED TO AREAS CLOSER TO THE LAKE. INCREASE IN CLOUD COVER PREDICATED A SLIGHT UPWARD ADJUSTMENT IN MIN TEMPS IN THIS AREA. ALSO RAISED MINS A TAD IN THE SLV WHERE PERSISTENT LIGHT SOUTHWESTERLY FLOW TONIGHT SHOULD KEEP READINGS FROM COMPLETELY RADIATING OUT. REST OF FORECAST REMAINS IN GOOD SHAPE. HAVE A GREAT NIGHT.
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&& .SHORT TERM /7 AM THIS MORNING THROUGH SUNDAY NIGHT/...
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AS OF 336 PM EST FRIDAY...STRONG SFC HIGH PRESSURE REMAINS ANCHORED OVER THE NERN CONUS THROUGH SUNDAY MORNING...PROVIDING CONTINUED DRY AND MOSTLY CLEAR CONDITIONS THRU MOST OF THE WEEKEND. WITH THE INCREASING SUN ANGLE AS WE CLOSE OUT FEBRUARY...BUMPED HIGHS SEVERAL DEGREES ABOVE MOS CONSENSUS FOR SATURDAY AND SUNDAY...WITH READINGS REACHING THE LOW/MID 20S FOR SATURDAY IN VALLEY LOCATIONS...AND MID/UPR 20S ON SUNDAY. WILL SEE AN INCREASE IN MID-UPPER LEVEL CLOUDS DURING THE AFTN HOURS SUNDAY AS FRONTAL WAVE TRACKS EWD ACROSS THE OH VALLEY AND MID-LEVEL WAA REGIME COMMENCES ACROSS NY/NEW ENGLAND. PRESSURE GRADIENT ALSO INCREASES AS SFC ANTICYCLONE SHIFTS EWD INTO THE GULF OF MAINE. THUS...WILL SEE SOUTH-SSW WINDS 10-15 MPH (WITH SOME GUSTS 20-25 MPH SUNDAY AFTN IN THE CHAMPLAIN VALLEY). INCREASING 850-700MB WAA AND ISENTROPIC ASCENT ALLOWS WIDESPREAD LIGHT SNOW TO DEVELOP ACROSS THE NORTH COUNTRY FROM SW-NE DURING SUNDAY EVENING. SHOULD SEE PERIODS OF LIGHT SNOW CONTINUING THROUGH THE OVERNIGHT HOURS WITH 2-3" OF ACCUMULATION BY DAYBREAK MONDAY IN MOST SPOTS. OVERCAST SKIES AND CONTINUED LIGHT S-SW WINDS WILL KEEP TEMPS FROM FALLING MUCH SUNDAY NIGHT WITH OVERNIGHT LOWS MAINLY IN THE MID-UPR TEENS.
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&& .LONG TERM /MONDAY THROUGH FRIDAY/...
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AS OF 336 PM EST FRIDAY... MONDAY... A WEAK UPPER LEVEL TROUGH WILL BE PASSING THROUGH THE AREA BRINGING CHANCE TO LIKELY POPS ACROSS THE NORTH COUNTRY AS A SURFACE LOW PRESSURE SYSTEM SLIDES TOWARDS THE EAST NORTHEAST. THIS WILL RESULT IN TEMPS SLIGHTLY BELOW NORMAL RANGING FROM THE MID TO UPPER 20S ACROSS THE AREA FOR MAX TEMPS AND THE OVERNIGHT LOWS IN THE SINGLE DIGITS ABOVE ZERO IN THE VALLEYS WITH SINGLE DIGITS BELOW ZERO IN THE NORTHEAST KINGDOM AND IN THE ADIRONDACK MOUNTAINS. MODERATELY STRONG WESTERLY WINDS WILL BE LIKELY ON THE SOUTHERN EXTENT OF THE UPPER LEVEL TROUGH AS THERE WILL BE A DECENT PRESSURE GRADIENT FORCE BETWEEN THE 1008MB LOW OVER THE GULF OF MAINE AND THE 1034MB HIGH CENTERED OVER IOWA. THIS SHOULD PRODUCE WESTERLY WINDS BETWEEN 10-15KTS GUSTING TO 25KTS ACROSS THE VALLEYS WITH MUCH HIGHER VALUES AT THE SUMMITS GUSTING TO NEARLY 45KTS AT THE TOP OF WHITEFACE MOUNTAIN AND MT MANSFIELD. THE WESTERLY WINDS WILL LEAD TO SOME ADDITIONAL UPSLOPE SNOWFALL ON THE WESTERN SLOPES OF BOTH THE GREENS AND THE ADIRONDACKS SO THAT WOULD BE WHERE I`D EXPECT THE MOST SIGNIFICANT SNOWFALL ACCUMULATIONS. EVEN SO, I`M ONLY LOOKING AT ADDITIONAL SNOWFALL OF 0.5 TO 1.5" INCHES ON MONDAY AND THEN THE PRECIP SHOULD END SHARPLY AS THE LOW CONTINUES OFFSHORE AND HIGH PRESSURE SETS IN. TUESDAY... THE HIGH PRESSURE WILL BUILD INTO THE AREA LEAVING SLIGHTLY COOLER TEMPERATURES THAN MONDAY BUT STILL WELL ABOVE WHAT WE`VE BEEN SEEING MOST OF FEBRUARY. EVEN BEHIND THE MILD FRONT THAT PASSES THROUGH ON MONDAY, THE RISING SUN ANGLE WILL ALLOW FOR TEMPS TO BE IN THE LOW TO MID 20S ACROSS THE AREA. THE PRESSURE GRADIENT THAT CAUSED MONDAY`S WINDS WILL HAVE SUBSIDED LEAVING LIGHT AND VARIABLE WINDS ACROSS THE AREA SHIFTING FROM MAINLY WESTERLY WINDS TO SOUTHERLY WINDS. OVERNIGHT LOWS TUESDAY NIGHT INTO WEDNESDAY MORNING WILL ONLY DROP BY A FEW DEGREES AS THE SOUTHERLY WARMER RETURN FLOW WILL SET IN OVERNIGHT BEHIND THE DEPARTING HIGH. WEDNESDAY...THERE ARE TWO SLIGHTLY DIFFERING SOLUTIONS FOR THE FORECAST ON WEDNESDAY. THE BROAD SENSE OF THE FORECAST IS THAT A DEVELOPING UPPER LEVEL RIDGE NORTH OF THE GREAT LAKES WILL SPAWN A SURFACE LOW PRESSURE SYSTEM OVER THE GREAT LAKES. THAT SURFACE SYSTEM WILL FEED OFF BOTH A NORTHERLY STREAM OF ENERGY AND A SOUTHERLY STREAM OF MOISTURE FROM THE DEPARTING HIGH PRESSURE SYSTEM. THE NET RESULT IS A WIDESPREAD PRECIPITATION EVENT WEDNESDAY MORNING INTO THE EARLY AFTERNOON. FOR THE FIRST TIME IN A LONG TIME THE CURRENT IDEA IS THAT RAIN WILL BE LIKELY AT SOME POINT ON WEDNESDAY MORNING. AS THE LOW LEVEL WARM ADVECTION PUSHES INTO THE AREA TEMPS WILL WARM INTO THE UPPER 30S TO LOW 40S ACROSS THE NORTH COUNTRY ON WEDNESDAY. AS SUCH THERE WILL BE A WINTRY MIX OF SNOW TRANSITIONING TO RAIN ON WEDNESDAY BY MORNING AND THEN BACK TO SNOW IN THE LATE AFTERNOON/EVENING. USING THE GFS AS THE THERMAL PROFILE GAVE ME QUITE THE MIX OF PTYPES. FOR THE TIME BEING I OPTED TO REMOVE FREEZING RAIN FROM THE FORECAST TRANSITION AND TRANSITION STRAIGHT FROM SNOW TO SLEET AND THEN TO RAIN. THERE WILL LIKELY BE A SMALL WINDOW OF FREEZING RAIN BUT AT 5 AND 6 DAYS OUT I JUST DON`T HAVE THAT KIND OF CONFIDENCE IN THE TIMING OF THAT WINDOW. I DID HOWEVER WANT TO ESTABLISH THE WINTRY MIX AND THUS NOT JUST POINT TO RAIN OR SNOW. 1000-500MB THICKNESS LEVELS WILL BE APPROACH 5500 METERS WELL ABOVE THE "MAGIC" 5400 METER LINE FOR RAIN/SNOW. RIGHT NOW I WENT WITH A CONSENSUS OF BOTH THE GFS AND ECMWF ON TIMING/LOCATION/INTENSITY BUT I FAVORED THE TRACK OF THE ECMWF A BIT MORE BECAUSE THE GFS POINTS TO A LOW TRACKING UP THE SAINT LAWRENCE VALLEY AND THEN BOMBING OUT OVER THE CANADIAN MARITIMES. CLIMATOLOGICALLY SPEAKING THATS QUITE RARE AND TYPICALLY DOESN`T HAPPEN. THE BOMBING LOWS TYPICALLY RUN UP THE COASTAL SO CONSIDER ME SKEPTICAL OF THAT SOLUTION FOR THE TIME BEING. AS THE LOW PUSHED THROUGH THE REGION THERE WILL BE MODERATELY STRONG WINDS ESPECIALLY ALOFT GUSTY TO 40-50KTS ABOVE 2000 FT. THURSDAY... THE SURFACE LOW THAT BROUGHT THE SNOWFALL WILL BE PUSHING WELL OUT OF THE AREA TOWARDS THE NORTHEAST GIVING WAY TO ANOTHER BROAD RIDGE OF HIGH PRESSURE. EARLY IN THE MORNING THURSDAY A BURST OF ENERGY FROM THE UPPER LEVEL TROUGH AND THE NORTHERLY WRAP AROUND WINDS ALOFT WILL PRODUCE A DECENT SHOT AT OROGRAPHIC SNOW SHOWERS IN THE ADIRONDACKS AND THE GREENS SO I WENT CHANCE POPS THROUGH THE DAY ON THURSDAY WITH SLIGHT CHANGE BEGINNING EVERYWHERE ELSE BY THURSDAY MID MORNING. THE ADVANCING HIGH PRESSURE SYSTEM WILL BRING MAX TEMPS AROUND 30 IN THE CHAMPLAIN VALLEY WITH LOW TO MID 20S ELSEWHERE ACROSS THE FORECAST REGION. OVERNIGHT LOWS ON THURSDAY WILL BE IN THE SINGLE DIGITS AGAIN AS THE HIGH PRESSURE SETS IN AND WE WILL DEVELOP DECENT RADIATIONAL COOLING CONDITIONS WITH LIGHT WINDS AND UNDER PARTLY CLOUDY SKIES. FRIDAY... ONCE AGAIN TEMPS WILL ONLY WARM TO THE UPPER TEENS TO LOW 20S UNDER THE STRONG HIGH PRESSURE SYSTEM AND ONLY MARGINAL CHANCES OF SOME OROGRAPHIC SNOW SHOWERS IN THE HIGHER TERRAIN OF THE GREENS AND THE ADIRONDACKS.
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&& .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... THROUGH 06Z SUNDAY...VFR EXPECTED THROUGH THE PERIOD WITH GENERALLY CLEAR SKIES AND LIGHT WINDS AS HIGH PRESSURE MAINTAINS CONTROL. EXCEPTION IS SLK WHICH WILL SEE SOME LOW CLOUDS THROUGH SATURDAY MORNING WITH OCNL MVFR CONDITIONS. WINDS LIGHT WESTERLY EXCEPT SOUTHWEST AND A BIT GUSTY AT TIMES AT MSS/SLK DURING SATURDAY. OUTLOOK 06Z SUNDAY THROUGH WEDNESDAY... 06Z SUNDAY-18Z SUNDAY...MAINLY VFR WITH HIGH PRESSURE. 18Z SUNDAY-00Z TUESDAY...DEVELOPING WARM FRONT AND ASSOCIATED WEAK AREA OF LOW PRESSURE WILL INCREASE THE CLOUDS WITH SNOW LIKELY BY 00Z MONDAY. EXPECT MVFR WITH PERIODS OF IFR. 00Z TUESDAY-18Z TUESDAY...VFR CONDITIONS UNDER HIGH PRESSURE. 18Z TUESDAY ONWARD...INCREASING CHANCE FOR MVFR/IFR IN MIXED PRECIPITATION AS WARM FRONT APPROACHES FROM THE SOUTHWEST. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...JMG/NEILES SHORT TERM...BANACOS LONG TERM...DEAL AVIATION...RJS

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