Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 010545 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1245 AM EST SUN MAR 1 2015 .SYNOPSIS... DRY WEATHER CONTINUES TONIGHT WITH HIGH PRESSURE OVER THE AREA. CLOUDS WILL BE ON THE INCREASE SUNDAY AS A WARM FRONT APPROACHES THE REGION. THIS FEATURE WILL ALSO SPREAD SNOW ACROSS THE AREA LATE SUNDAY AFTERNOON AND ESPECIALLY SUNDAY NIGHT. LIGHT SNOW ACCUMULATIONS ARE EXPECTED BY MONDAY MORNING BEFORE THE SNOW TAPERS OFF THROUGHOUT THE DAY. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... AS OF 1205 AM EST SUNDAY...GOING FORECAST IN GOOD SHAPE...NO SIGNIFICANT CHANGES MADE. HIGH PRESSURE OVER THE REGION WILL ALLOW FOR CLEAR SKIES TO DOMINATE MUCH OF THE NIGHT. ANY EARLIER LAKE EFFECT CLOUDS DOWNWIND OF LAKE ONTARIO HAVE SINCE DISSIPATED. OTHERWISE...WILL SEE AN INCREASE IN HIGH CLOUDS TOWARDS MORNING AS A SYSTEM APPROACHES FROM THE OHIO VALLEY. LOOKING AT LOWS GENERALLY IN THE SINGLE DIGITS ABOVE AND BELOW ZERO...WITH SOME -10 TO -15 DEGREE READINGS POSSIBLE IN THE COLDEST HOLLOWS OF THE NORTHEAST KINGDOM. && .SHORT TERM /7 AM THIS MORNING THROUGH MONDAY NIGHT/... AS OF 326 PM EST SATURDAY...FORECAST REMAINS ON TRACK FOR THE SUNDAY-MONDAY TIME PERIOD WITH INCREASING CLOUDS AND SNOW LATER SUNDAY AND SUNDAY NIGHT BEFORE TAPERING OFF TO SNOW SHOWERS ON MONDAY. WARM FRONT...WARM AIR ADVECTION...AND EVENTUALLY THE UPPER LEVEL TROUGH WILL ALL MOVE ACROSS THE NORTHEAST UNITED STATES AND PROVIDE THE NECESSARY SUPPORT FOR THE SNOW. THESE FEATURES ARE FAIRLY PROGRESSIVE AND NOT VERY STRONG...BUT ENOUGH TO PRODUCE ACCUMULATING SNOWS ACROSS NORTHERN NEW YORK. LOOKING AT A WIDESPREAD 1 TO 3 INCH SNOW ACROSS THE AREA WITH 2 TO 4 INCHES IN THE MOUNTAINS AND PERHAPS SOME LOCALIZED AMOUNTS AROUND 5 INCHES FOR THE SOUTHERN GREEN MOUNTAINS OF VERMONT. AGAIN MAIN TIME FOR THIS SNOW WILL BE LATE IN THE DAY SUNDAY AND ESPECIALLY SUNDAY NIGHT. SOUTHWEST FLOW ALOFT WILL BE A DOWNSLOPING FLOW AND PARTS OF THE CHAMPLAIN VALLEY WILL LIKELY SEE THE LEAST AMOUNT OF SNOW FROM THIS EVENT. THE UPPER TROUGH MOVES ACROSS THE REGION ON MONDAY AND THE SNOW QUICKLY TAPERS TO SNOW SHOWERS WITH THE MOUNTAINS HAVING THE BEST CHANCE FOR ADDITIONAL LIGHT SNOW ACCUMULATIONS. THE SOUTHWEST FLOW ALOFT WILL LEAD TO WARMER TEMPERATURES ON SUNDAY AND MONDAY WITH HIGHS IN THE 20S TO AROUND 30. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 343 PM EST SATURDAY... TUESDAY... NEARLY ALL OF THE AVAILABLE GUIDANCE SHOWS THE HIGH PRESSURE SLIDING OFFSHORE BY MONDAY AFTERNOON. THE WEST NORTHWESTERLY WINDS THAT WILL KEEP TEMPS FROM WARMING MUCH ON TUESDAY WILL GIVE WAY TO WARMER RETURN FLOW SOUTHERLY WINDS BY MID AFTERNOON WHICH SHOULD ENABLE THE AREA TO WARM INTO THE MID 20`S ACROSS THE FORECAST REGION BETWEEN NOON AND 7PM ON TUESDAY. THE WARMEST TIME OF THE DAY ON TUESDAY WILL ACTUALLY BE DURING THE EVENING HOURS AS THE RETURN FLOW WILL PUSH WARMER AIR INTO THE REGION THROUGH THE EVENING AHEAD OF AN ADVANCING SYSTEM. THE TEMPERATURE TRENDS TUESDAY EVENING WILL ABSOLUTELY BE NON DIURNAL AS OUR OVERNIGHT LOW WILL LIKELY OCCUR JUST AS PERIOD BEGINS AROUND 7- 8PM. WEDNESDAY...THE MODELS HAVE COME INTO SLIGHTLY BETTER CONSENSUS TODAY BUT STILL OFFER SLIGHTLY DIFFERENT SOLUTIONS THERMALLY. THE BROAD SENSE OF THE FORECAST REMAINS THAT A DEVELOPING UPPER LEVEL TROUGH 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 AND TRACK UP THE SAINT LAWRENCE VALLEY. THE NET RESULT WILL BE A WIDESPREAD PRECIPITATION EVENT WEDNESDAY EARLY MORNING INTO THE EARLY AFTERNOON. PTYPE REMAINS THE BIGGEST FORECAST CHALLENGE FOR THIS EVENT AS ITS CURRENTLY TOO FAR IN THE FUTURE TO HAVE MUCH CERTAINTY IN HOW FAR NORTH THE MODELS BRING THE WARM AIR BEFORE THE COLD FRONT REACHES THE AREA. THE GFS DEVELOPS A STRONGER LOW PRESSURE SYSTEM THAN THE ECMWF WHICH IS MORE OF AN EMBEDDED SHORT WAVE CONNECTED TO AN UPSTREAM LOW PRESSURE SYSTEM. GIVEN THE TWO SCENARIOS AT THIS POINT I OPTED FOR A BLEND OF THE TWO SOLUTIONS REGARDING POPS AND SURFACE TEMPS. THE GFS IS NO LONGER SHOWING A SIGNIFICANT SURFACE BOMB DEVELOPING WHICH LEADS TO ENHANCED CONFIDENCE IN THIS RUN VERSUS YESTERDAYS 12Z RUN. FOR THERMAL PROFILES I OPTED TO CONTINUE TO USE THE GFS BECAUSE OF THE EXTRA VERTICAL LEVELS AVAILABLE FOR A TOP DOWN PTYPE APPROACH. THIS LEAD TO THE ONSET OF THE PRECIP BEGINNING AS LIGHT SNOW SHOWERS THEN TRANSITIONING BY MIDNIGHT OVER NORTHERN NEW YORK TO A WINTRY MIX. THAT WILL CONTINUE TO TRANSITIONS FROM THE SOUTHWEST TO NORTHEAST SHIFTING MORE TOWARDS RAIN AND FREEZING RAIN BY MID MORNING ON WEDNESDAY. THE CONCERN RIGHT NOW IS HOW TO DEAL WITH THE RAIN THAT FALLS AND MEETS ROADS WHERE GROUND TEMPS WILL STILL POTENTIALLY BE AT OR BELOW 32F. EITHER WAY THE NEXT RESULT OF RAIN OR FREEZING RAIN WOULD BE ICING ON THE ROAD SURFACES AND THE CURRENT SNOW PACK. AS THE LOW PUSHES THROUGH THE REGION THERE WILL BE MODERATELY STRONG WINDS ESPECIALLY ALOFT GUSTING TO 40-50KTS ABOVE 2000 FT. CURRENTLY THE ECMWF RUNS A SOUTHWESTERLY JET AT 850MB APPROACHING 60KTS INTO THE SAINT LAWRENCE VALLEY AND 850MB WINDS BETWEEN 45-55KTS INTO THE CHAMPLAIN VALLEY AND WESTERN SLOPE OF THE GREENS. GIVEN THE SOUTHWESTERLY COMPONENT OF THE WINDS ALOFT AT 850 AND 700MB EXPECT THAT WOULD RESULT IN SHADOWING OF THE CHAMPLAIN VALLEY SO TOTAL QPF WOULD BE LOWERED IN THE CHAMPLAIN VALLEY AND IN THE NORTHEAST KINGDOM. THE GFS DOES A DECENT JOB OF SHOWING THAT AS OF THE 12Z RUN. MAX TEMPS ON THURSDAY AHEAD OF THE RESULTANT COLD FRONT THAT WILL PASS IN THE MID AFTERNOON HAVE A REAL GOOD SHOT AT WARMING INTO THE MID TO LOW 40S UNDER STRONG SOUTHWESTERLY FLOW. THE LATER THE FRONT COMES THROUGH THE BETTER SHOT AT NEAR 50 DEGREES FOR SOUTHERN VERMONT NEAR RUTLAND. I OPTED TO GO SLIGHTLY ABOVE GUIDANCE ON WEDNESDAY FOR MAX TEMPS BUT WAS A BIT RESERVED IN HOW FAR ABOVE GUIDANCE BECAUSE THE CURRENT EXISTING SNOW PACK SHOULD MODERATE HOW MUCH LOW LEVEL WARMING IS POSSIBLE. THURSDAY... THE SURFACE LOW WILL PUSH OUT OF THE AREA GIVING WAY TO ANOTHER BUILDING SURFACE RIDGE BELOW A WEAK UPPER LEVEL TROUGH. THE RESULT OF THAT COMBINATION WILL BRING COLD TEMPS ONCE AGAIN AS WE WILL STRUGGLE TO WARM BEHIND THE COLD FRONT INTO THE MID 20S IN THE VALLEYS AND UPPER TEENS ACROSS THE HIGHER TERRAIN OF THE ADIRONDACKS AND GREEN MOUNTAINS. ANY LINGERING UPPER LEVEL ENERGY WILL SQUEEZE OUT A FEW OROGRAPHIC SNOW SHOWERS SO I DIDN`T REMOVE ALL THE POPS UNTIL LATE THURSDAY EVENING. AS THE RIDGE BUILDS IN THE CLOUDS WILL DECREASE AND THE MODERATE WINDS WILL SLOWLY WEAKEN BECOMING LIGHT AND WESTERLY TOWARDS INTO THE EVENING. OVERNIGHT THE DECREASING CLOUD COVER AND WEAKENING WINDS SHOULD ALLOW THE NOCTURNAL WINDS OVER SOUTHERN VERMONT TO DECOUPLE ALLOWING FOR GOOD RADIATIONAL COOLING IN VERMONT WITH DECENT COOLING EXPECTED FURTHER NORTH. OVERNIGHT LOWS WILL BE IN THE LOW SINGLE DIGITS ACROSS THE AREA WITH TEMPS JUST BELOW ZERO IN THE TYPICAL COOL SPOTS OVER THE NORTHEAST KINGDOM AND ACROSS SARANAC LAKE. FRIDAY...UNDER STRONG HIGH PRESSURE THE WEATHER WILL BE DRY AND TEMPS WILL ONLY WARM TO THE UPPER TEENS TO LOW 20S. NOT MUCH ELSE TO DISCUSS. OVERNIGHT LOWS WILL BE IN THE LOW TEENS IN THE VALLEYS WITH SINGLE DIGITS ABOVE ZERO EXPECT ELSEWHERE. SATURDAY...AT DAY 7 ONE CAN ONLY PUT SO MUCH STOCK IN THE MODELS AND SO I JUST WENT WITH THE ECMWF WHICH DOESN`T CURRENTLY PROJECT A STRONG LOW LEVEL TROUGH ADVANCING THROUGH THE REGION. BASED ON THE CURRENT GUIDANCE EXPECTED THE BROAD AREA OF HIGH PRESSURE TO STILL BE OVER THE REGION RESULTING IN TEMPS IN THE MID 30S UNDER SOUTHERLY TO SOUTHWESTERLY WINDS. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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THROUGH 06Z MONDAY...VFR EXPECTED THROUGH SUNDAY MORNING WITH CLEAR SKIES FOLLOWED BY LOWERING MID/HIGH CLOUDS. CONDITIONS DETERIORATE RAPIDLY BETWEEN 17Z-20Z TO MVFR/IFR IN LIGHT SNOW AND CONTINUE SUNDAY NIGHT. GREATEST IMPACTS AT RUT/MSS/SLK/MPV WITH LEAST AT PBG/BTV WITH DOWNSLOPING SOUTHWESTERLY FLOW. SURFACE WINDS ON SUNDAY STRENGTHEN OUT OF THE SOUTH TO 5-15 KNOTS...WITH GUSTS UP TO 20 KNOTS AT BTV. OUTLOOK 06Z MONDAY THROUGH THURSDAY... 06Z MONDAY-12Z MONDAY...MAINLY IFR IN LIGHT SNOW. 12Z MONDAY-00Z TUESDAY...VARIETY OF FLIGHT CATEGORIES IN SNOW SHOWERS WITH WEAK LOW PRESSURE SYSTEM. GREATEST CHANCES OF IFR OR LOWER AT MPV/SLK. 00Z TUESDAY-18Z TUESDAY...VFR CONDITIONS UNDER HIGH PRESSURE. 18Z TUESDAY-00Z THURSDAY...MVFR/IFR IN MIXED PRECIPITATION AS LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTHWEST. 00Z THURSDAY ONWARD...MAINLY VFR WITH AREAS OF MVFR/IFR IN SNOW SHOWERS.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...EVENSON NEAR TERM...EVENSON/NEILES/MUCCILLI SHORT TERM...EVENSON LONG TERM...DEAL AVIATION...RJS

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