317
FXUS61 KBTV 210635
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
135 AM EST SAT NOV 21 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 TODAY/
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 /TONIGHT 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 /06Z SATURDAY THROUGH WEDNESDAY/
THROUGH 06Z SUNDAY...ABUNDANT LLVL MOISTURE REMAINS OVER THE
FORECAST AREA. EXPECT MVFR CIGS AT MOST TAF SITES OVERNIGHT WITH
IFR AT KSLK. EXPECT CIGS TO GRADUALLY IMPROVE DURING
SATURDAY...IMPROVING TO VFR LATE AFTERNOON. HIGHER TERRAIN WILL BE
OBSCURED IN CLOUDS THROUGH THE PERIOD. SOME AREAS OF SURFACE WIND
GUSTS OF 20 KTS OR GREATER ARE EXPECTED THROUGH AROUND 08Z. WINDS
WILL BE W TO NW AROUND 10 KTS DURING SATURDAY...DIMINISHING
THROUGH THE NIGHT TO LIGHT AND VARIABLE AFTER 02Z SUNDAY. LOOK FOR
THE POTENTIAL FOR FOG TO FORM AFTER 05Z SUNDAY AT PRONE LOCATIONS
LIKE KMPV AND KSLK WITH MVFR VIS.
OUTLOOK 06Z SUNDAY THROUGH WEDNESDAY...MVFR VIS POSSLIBLE AT KMPV
AND KSLK WITH BR THROUGH 13Z SUNDAY. OTHERWISE VFR CONDITIONS
ANTICIPATED FOR MUCH OF THE PERIOD AS FORECAST AREA EXPECTED TO BE
UNDER GENERAL AREA OF HIGH PRESSURE. SOME SCATTERED SHOWERS ARE
POSSIBLE TUESDAY NIGHT...BUT WITH GENERAL VFR CONDITIONS
BTV WATCHES/WARNINGS/ADVISORIES
VT...NONE.
NY...NONE.
SYNOPSIS...JMG
NEAR TERM...JMG/MB
SHORT TERM...JMG
LONG TERM...WGH
AVIATION...AMF/RJS
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