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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 100032
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
732 PM EST TUE FEB 9 2010

.SYNOPSIS...
FAIR CONDITIONS WILL PREVAIL ACROSS THE NORTH COUNTRY LATE THIS
AFTERNOON INTO TONIGHT AS A NARROW RIDGE OF HIGH PRESSURE CRESTS
OVER THE AREA. MEANWHILE...A STRENGTHENING STORM SYSTEM ACROSS THE
OHIO RIVER VALLEY WILL TRANSFER TO THE COAST OFF THE MID-ATLANTIC
STATES LATE TONIGHT AND THEN TRACK EASTWARD ACROSS THE WATERS SOUTH
OF NEW ENGLAND. THE NORTHERN FRINGE OF THIS SYSTEM WILL BRING LIGHT
SNOW TO THE NORTH COUNTRY WEDNESDAY...WITH UP TO 2 TO 4 INCHES OF
SNOW ACCUMULATION ACROSS SOUTHERN RUTLAND AND WINDSOR COUNTIES IN
VERMONT...AND LESSER AMOUNTS TO THE NORTH. THEREAFTER...SEASONABLE
TEMPERATURES ARE EXPECTED WITH NORTHWESTERLY WINDS BRINGING CHANCES
FOR SNOW SHOWERS ACROSS THE MOUNTAINS THURSDAY NIGHT AND FRIDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 225 PM EST TUESDAY...FLAT PRESSURE GRADIENT CONTRIBUTING TO LIGHT
AND VARIABLE WINDS THIS AFTN INTO THIS EVENING. MODEL SOUNDINGS
INDICATE RESIDUAL TEMPERATURE INVERSION LAYER ROUGHLY
925-850MB...WHICH IS PREVENTING COMPLETE CLEARING OF CLOUDS ACROSS
THE NORTHERN CHAMPLAIN VALLEY EWD ACROSS N-CENTRAL/NERN VT. THIS
CLOUDS MAY BRIEFLY DISSIPATE THIS EVENING WITH CONTINUED
SUBSIDENCE...BUT WILL BE FOLLOWED QUICKLY BY CIRRUS AND
ALTOSTRATUS DECK ADVANCING QUICKLY ACROSS CENTRAL/WRN NY PER 19Z
VISIBLE IMAGERY. THUS...HAVE SHOWN INCREASING CLOUDS OVERNIGHT
MOST LOCATIONS AS MID-HIGH LEVEL MOISTURE ASSOCIATED WITH VIGOROUS
OHIO VALLEY THROUGH ADVECTS NEWD. TEMPERATURES WILL FALL MOST
RAPIDLY LATE THIS EVENING...THEN LEVEL OUT SOMEWHAT WITH ONSET OF
THICKER CLOUD COVER. LOWS WILL GENERALLY SETTLE IN THE
TEENS...WITH A FEW UPR SINGLE DIGITS POSSIBLE ACROSS THE OUTLYING
PORTIONS OF CALEDONIA/ESSEX COUNTIES IN NERN VT.

NOT MUCH IN THE WAY OF SNOWFALL CHANCES OVERNIGHT...HOWEVER
HAVE INDICATED A 20-30 POP TOWARD DAYBREAK ACROSS WRN ST. LAWRENCE
COUNTY IN NY AND ALONG OUR CWA BORDER THRU THE CENTRAL ADIRONDACKS
INTO RUTLAND COUNTY VT. THIS WILL BE ALONG EXTREME NRN EDGE OF
DYNAMICS/BETTER FORCING FOR ASCENT WITH PRIMARY VORT SHIFTING INTO
WRN PA/WV TOWARD 12Z WEDNESDAY. MORE SIGNIFICANT SNOWFALL WILL
REMAIN TO OUR SOUTH AND WEST.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 225 PM EST TUESDAY...WHILE MAJOR WINTER STORM IMPACTS ARE EXPECTED
TO REMAIN TO OUR SOUTH ON WEDNESDAY...A SLIGHT NWD SHIFT IN LOW
TRACK PER 12Z NWP GUIDANCE SUITE SHOULD YIELD POTENTIAL FOR 2-4
INCH SNOWFALL ACROSS RUTLAND/WINDSOR COUNTIES ON WEDNESDAY...WITH
PROSPECTS FOR STEADIEST SNOW DURING THE AFTN HOURS. HAVE NOTED
THAT EASTERLY 850MB FLOW INCREASES AT 30-35 KTS DURING 18Z WED
THRU 00Z THU PER 12Z NAM MODEL SOUNDING AT KVSF. THIS GENERALLY
RESULTS IN UPSLOPE ENHANCEMENT OF SNOWFALL ALONG THE EASTERN
SLOPES OF THE GREEN MTNS...TYPICALLY NOTED FROM LUDLOW TO BETHEL.
CAN/T RULE OUT SOME 4-5" TOTALS IN THESE UPSLOPE AREAS...AND WILL
NEED TO BE MONITORED FOR A POSSIBLE WINTER WEATHER ADVISORY ACROSS
RUTLAND/WINDSOR COUNTIES. HAVE INDICATED AN 80 POP FOR S-CENTRAL
VT WEDNESDAY AFTERNOON...TAPERING DOWN TO AROUND 30 PERCENT FOR
PBG/BTV/1V4. ELSEWHERE...NLY LOW-LEVEL WINDS WILL SUPPLY DRY
BOUNDARY LAYER AIR TO MOST SECTIONS...ESPECIALLY ACROSS THE
CHAMPLAIN VALLEY WHERE NORTH WINDS WILL BE CHANNELED AND SOMEWHAT
STRONGER. SOME NLY GUSTS 20-25 KTS ARE POSSIBLE IN THE IMMEDIATE
CHAMPLAIN VALLEY DURING THE AFTERNOON...ESPECIALLY OVER LAKE
CHAMPLAIN. WITH DRY PBL...HAVE MENTIONED ONLY A CHANCE FOR LIGHT
SNOW ACROSS CENTRAL/NRN VERMONT. COULD SEE 1-2" ACROSS
ADDISON/WASHINGTON/ORANGE COUNTIES IN VERMONT AND OUR SRN
ADIRONDACK PORTION...AND GENERALLY AN INCH OR LESS FOR POINTS
NORTH INCLUDING THE GREATER BURLINGTON AREA. WITH NORTH WINDS IN
PLACE...HAVE UNDERCUT THE MOS HIGHS SLIGHTLY ON WEDNESDAY. HIGHS
WILL GENERALLY RANGE FROM 25-30F...HIGHEST IN THE UPPER CT VALLEY
REGION.

LOW-LEVELS DRY FAIRLY QUICKLY WEDNESDAY NIGHT...SO STRATIFORM SNOW
SHOULD END DURING THE EVENING AND LINGERING SNOW SHOWERS WILL
PROBABLY BE LIMITED TO THE HIGHER ELEVATIONS. AS SFC LOW DEEPENS
SOUTHEAST OF NEW ENGLAND...NORTH WINDS WILL CONTINUE AROUND 10-15
MPH WEDNESDAY NIGHT...WITH GUSTS TO 25 MPH FOR CENTRAL/ERN VT.
GENERALLY FAIR AND DRY CONDITIONS THURSDAY WITH NWLY LOW-LEVEL FLOW
AND PARTLY SUNNY SKIES. HIGHS THURSDAY ARE EXPECTED TO BE IN THE
25-30F RANGE EXCEPT NEAR 32F AROUND SPRINGFIELD VT. SOME INCREASE IN
RH NOTED 925-700MB LAYER THURSDAY NIGHT...SO HAVE INDICATED 30-40
POPS FOR SNOW SHOWERS IN THE MTNS DURING THIS PERIOD...WITH SOME
LIGHT SNOW ACCUMULATIONS POSSIBLE IN THE HIGHER ELEVATIONS /1-2
INCHES/. LOWS WILL REMAIN NEAR SEASONAL LEVELS THURSDAY
NIGHT...GENERALLY 5-15F.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM EST TUESDAY...THE LONG TERM CHALLENGE WL BE TIMING OF
MOISTURE AND ASSOCIATED ENERGY WITH SEMI-STATIONARY MID/UPPER LVL
TROF ACRS NE CONUS/EASTERN CANADA. THIS FEATURE WL CONT TO PROVIDE
CWA WITH AT OR SLIGHTLY BLW NORMAL TEMPS AND MAINLY BLW NORMAL
CHCS FOR PRECIP. HOWEVER...THE MOUNTAINS WL CONT TO EXPERIENCE ON
AND OFF SNOW SHOWERS FOR DAYS 4 THRU 7 WITH ACCUMULATIONS MUCH
LIKE THE PREVIOUS COUPLE WEEKS ANTICIPATED. OVERALL GFS/ECMWF AND
LATEST ENSEMBLES DATA SUPPORT REDEVELOPMENT OF DEEP CYCLONIC TROF
ACRS THE NE CONUS. THIS WL CREATE A FAVORABLE UPSLOPE FLW WL
INCREASE 850 TO 700MB MOISTURE ADVECTION OCCURRING ON NE FLW
ALOFT. FIRST SURGE OF ENHANCED DEEP LAYER MOISTURE OCCURS BTWN 12Z
FRIDAY THRU 06Z SATURDAY...WITH PWS NEAR 0.30. WL MENTION HIGH CHC
POPS ACRS THE NORTHERN DACKS/GREEN MTNS DURING THIS TIME
PERIOD...WITH ONLY SCHC POPS IN THE VALLEYS. SOME SNOW
ACCUMULATION WL BE POSSIBLE FROM JAY PEAK TO MOUNT MANSFIELD AND
ACRS THE NORTHERN DACKS FROM MALONE TO LYON MTN. NEXT SURGE OF
INCREASE MOISTURE OCCURS LATE SUNDAY INTO MONDAY...WITH MORE SNOW
SHOWERS EXPECTED. IN ADDITION...TO INCREASED 1000 TO 700MB
MOISTURE...GFS SHOWS GOOD LLVL UVVS FROM NW UPSLOPE FLW. WL PLACE
HIGH CHC POPS ONCE AGAIN ACRS THE MTN ZNS...WITH POTENTIAL FOR
SEVERAL PERIODS OF ACCUMULATING SNOWFALL. THE EXACT TIMING AND
DETAIL OF MOISTURE/LIFT WL NEED TO BE FINE TUNED IN THE UPCOMING
DAYS...BUT SEVERAL ROUNDS OF ACCUMULATING MTN SNOW SHOWERS WL BE
POSSIBLE FROM LATE THIS WEEK THRU EARLY NEXT WEEK. FOR
TEMPS...EXPECT AT OR SLIGHTLY BLW NORMAL HIGHS WITH NEAR NORMAL
LOWS DUE TO CLOUDS/WINDS. FEEL COOL NORTHERLY FLW AND PROGGED 85H
TEMPS BTWN -13C AND -16C WL SUPPORT HIGHS MAINLY IN THE M10S TO
M20S...WITH LOWS IN THE SINGLE DIGITS/M10S.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
THROUGH 18Z WEDNESDAY...HIGH CLOUDS ARE ADVANCING INTO THE NORTH
COUNTRY AHEAD OF A STORM SYSTEM WHICH WILL MAINLY IMPACT THE
SOUTHERN PORTIONS OF THE AREA TOMORROW. TONIGHT VFR CONDITIONS
WITH LIGHT WINDS WILL PREVAIL. BY 12Z CEILINGS WILL LOWER TO MVFR
AT MOST TAF SITES WITH VCSH AT KRUT AND KSLK. LIGHT SNOW WILL BEGIN
BY 14Z AT KRUT AND KSLK...WITH CEILINGS DROPPING TO IFR BY 18Z AT
KRUT AS SNOW INTENSIFIES A BIT. FURTHER NORTH LIGHT SNOW WILL SPREAD
NORTH TO KMPV AND EVENTUALLY KBTV AROUND 18Z WITH MVFR CEILINGS.
THE PRIMARY REASON FOR SNOW AT THESE LOCATIONS WILL BE DUE TO
NORTHWEST UPSLOPE FLOW AND CONVERGENCE IN THE VALLEY AND MTNS.
KMSS WILL SEE THE LEAST POTENTIAL FOR SNOW... BUT MOISTURE IN THE
ST. LAWRENCE VALLEY SHOULD BRING CEILINGS TO MVFR THERE AS WELL BY
MIDDAY. WINDS WILL BE LIGHT AND GENERALLY OUT OF THE NORTHEAST
THROUGH 16Z...THEN BECOME NORTH TO NORTHWEST. WINDS WILL INCREASE
TO 10-12 KT OUT OF THE NNW TOWARD THE END OF THE FORECAST PERIOD.

OUTLOOK 00Z THURSDAY THROUGH SATURDAY...
00Z THURSDAY THROUGH 12Z THURSDAY...MVFR IN AREAS OF SNOW
SHOWERS.
12Z THURSDAY THROUGH SAT...MAINLY VFR WITH OCCASIONAL MVFR IN
-SHSN ESPECIALLY AT MPV/SLK.
-- End Changed Discussion --

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...AMF/TABER