Issued by NWS Burlington, VT
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-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --000 FXUS61 KBTV 210330 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1030 PM EST FRI NOV 20 2009 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL PULL NORTHEAST AND AWAY FROM THE REGION TONIGHT INTO SATURDAY WITH ANY LINGERING RAIN SHOWERS ENDING. VARIABLE CLOUD COVER WILL LIKELY PERSIST WELL INTO SATURDAY HOWEVER...ESPECIALLY ACROSS NORTHERN AREAS WHERE RESIDUAL LOW LEVEL MOISTURE WILL HANG TOUGH. THEREAFTER...STRONG HIGH PRESSURE WILL BUILD ATOP THE REGION SATURDAY NIGHT INTO MONDAY WITH MAINLY FAIR SKIES AND SEASONABLE TEMPERATURES EXPECTED. && .NEAR TERM /THROUGH SATURDAY/... AS OF 925 PM EST FRIDAY...HAVE UPDATED THE FORECAST THIS EVENING...MAINLY TO FRESHEN UP THE WORDING. SATELLITE IMAGERY INDICATES DENSE CLOUD COVER WELL UPSTREAM INTO ONTARIO...SO ALSO UPPED CLOUD COVER TO MOSTLY CLOUDY OR CLOUDY IN ALL AREAS. MUCH OF THE EARLIER SHOWER ACTIVITY HAS DIMINISHED THIS EVENING...BUT STILL A FEW RETURNS APPEARING ON RADAR. WITH THE UPPER TROUGH STILL IN THE VICINITY AND WINDS FAVORABLE FOR UPSLOPE ESPECIALLY IN THE NORTHERN GREENS...KEPT THE CHANCE OF PRECIPITATION IN THE MOUNTAINS. HOWEVER...REMOVED MENTION OF SNOW FROM THE NORTHEAST KINGDOM AS THICK CLOUD COVER SHOULD PROHIBIT TEMPERATURES FROM DROPPING MUCH BELOW THE UPPER 30S. OTHERWISE THE GOING FORECAST LOOKS GOOD AND NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION...CURRENT FCST IN GOOD SHAPE AND ONLY MINOR ADJUSTMENTS MADE TO THE NEXT 12-18 HOURS. UPPER LVL LOW PRESSURE SWINGING BY NORTH OF CYUL THIS AFTERNOON WILL CONTINUE PULLING NORTHEAST AND AWAY FROM THE REGION OVERNIGHT. LINGERING LOW TO MID LEVEL MOISTURE WILL THIN THROUGH TIME...THOUGH WITH PASSG OF UPPER 500 MB TROUGH AXIS AND CURRENT RADAR TRENDS WILL CONTINUE WITH AT LEAST CHC POPS FOR OUR NRN MTNS THROUGH THE FIRST HALF OF TONIGHT. ACROSS THE LOWER ELEVATIONS MAINLY DRY CONDS EXPECTED AS WELL MIXED BNDRY LYR COMBINED WITH MEAN WESTERLY WIND COMPONENT SHOULD ENSURE COMPRESSIONAL/DOWNSLOPING EFFECTS. TEMPS FAIRLY UNIFORM GIVEN ONLY MARGINAL COLD AIR ADVECTIVE PROCESSES AND AT LEAST A DECENT DEGREE OF CLOUD COVER. THUS STUCK FAIRLY CLOSE TO MOS GUIDANCE HERE... OFFERING MINS GENERALLY FROM THE MID 30S TO THE LOWER 40S. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 220 PM EST FRIDAY...THEN MAINLY QUIET FOR THE REMAINDER OF THE SHORT TERM AS BROAD HIGH PRESSURE AT THE SFC AND ALOFT BUILDS EASTWARD FROM THE CENTRAL STATES. CLOUDS MAY PROVE A TAD SLUGGISH TO DEPART NRN AREAS DURING THE FIRST HALF OF THE DAY ON SATURDAY AS RESIDUAL CYCLONIC FLOW ALOFT SLOWLY FLATTENS...OTW EXPECT SKIES TO TREND MAINLY CLR BY SATURDAY EVENING AND PERSIST THROUGH SUNDAY/SUNDAY NIGHT. HAVE OFFERED MAX TEMPS NEAR OR SLIGHTLY ABV SEASONAL NORMS HERE BASED OFF 925 MB TEMPS AND THE EXPECTED CLEARING TREND...THOUGH HAVE UNDERCUT MOS GUIDANCE DURING THE OVERNIGHT PERIODS AS RADIATIVE EFFECTS DOMINATE UNDER LIGHT WINDS. OVERALL ANOTHER NICE NOVEMBER WEEKEND ON TAP WITH NO PCPN...INCREASING SUNSHINE...AND LIGHT WINDS. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 315 PM EST FRIDAY...MODELS NOT IN GOOD AGREEMENT IN THE EXTENDED FORECAST PERIOD...ESPECIALLY AT THE BEGINNING OF THE PERIOD ON MONDAY. ON MONDAY THE GFS MODEL TAKES A WEAK LOW ALONG THE MID ATLANTIC COAST MONDAY MORNING AND THEN BRING THIS LOW INTO SOUTHERN NEW ENGLAND BY 12Z TUESDAY. 12Z NAM AND 12Z ECMWF MODELS KEEP A RIDGE OF HIGH PRESSURE OVER THE REGION ON MONDAY...WITH THE ECMWF MODEL KEEPING THIS HIGH IN PLACE OVER THE REGION MONDAY NIGHT AND TUESDAY. THE GFS MODEL APPEARS TO BE THE OUTLIER WITH THIS LOW. THUS...HAVE LEANED TOWARD THE 12Z ECMWF FORECAST SOLUTION AND WILL KEEP THE REGION DRY FROM MONDAY THROUGH WEDNESDAY NIGHT...AS THIS MODEL KEEPS A RIDGE OF HIGH PRESSURE OVER THE REGION. ON THANKSGIVING DAY...12Z GFS AND 12Z ECMWF MODELS SHOWING RAIN SHOWERS MOVING INTO THE REGION DURING THE AFTERNOON. BOTH MODELS SHOW PRECIPITATION ACROSS THE REGION THURSDAY NIGHT AND FRIDAY. HOWEVER...GFS MODEL COLDER THEN THE ECMWF THURSDAY NIGHT AND FRIDAY...SO UNCERTAINTY EXISTS AS TO PRECIPITATION TYPE THURSDAY NIGHT AND FRIDAY. 12Z ECMWF MODEL MUCH WARMER THAN THE GFS AND IMPLIES MAINLY RAIN THURSDAY NIGHT AND FRIDAY. GIVEN THIS UNCERTAINTY... WILL MENTION A CHANCE OF RAIN OR SNOW THURSDAY NIGHT AND FRIDAY. HAVE GONE LOWER THAN MOS GUIDANCE FOR POPS MONDAY THROUGH THURSDAY MORNING. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...-- Changed Discussion --THROUGH 00Z SUNDAY...LOW PRESSURE MOVING AWAY FROM THE REGION TONIGHT...BUT ABUNDANT LLVL MOISTURE IN ITS WAKE. EXPECT MVFR CIGS AT MOST TAF SITES OVERNIGHT WITH IFR AT KSLK. SCATTERED LIGHT RAIN SHOWERS WILL BE ENDING OVERNIGHT. EXPECT CIGS TO GRADUALLY IMPROVE DURING SATURDAY...IMPROVING TO VFR DURING THE AFTERNOON... WITH CLOUDS THEN BECOMING SCT AT MOST SITES LATE IN THE DAY. HIGHER TERRAIN WILL BE OBSCURED IN CLOUDS THROUGH THE PERIOD. SOME AREAS OF SURFACE WIND GUSTS OF 20 KTS OR GREATER ARE EXPECTED ACROSS THE REGION THROUGH AROUND 06Z. WINDS WILL BE W TO NW AROUND 10 KTS DURING SATURDAY. OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY... VFR CONDITIONS ANTICIPATED FOR MUCH OF THE PERIOD AS FORECAST AREA EXPECTED TO BE UNDER GENERAL AREA OF HIGH PRESSURE.-- End Changed Discussion --&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG/MB SHORT TERM...JMG LONG TERM...WGH AVIATION...RJS
