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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 091927
AFDBTV

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

.SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 308 AM EST TUESDAY...MUCH OF THE EXTENDED WILL HAVE THE NORTH
COUNTRY UNDER INFLUENCE OF A LOW PRESSURE SYSTEM THAT STARTS OUT
OVER THE CANADIAN MARITIMES ON THURSDAY NGT...AND WILL EVENTUALLY
RETROGRADE WEST INTO QUEBEC THRU SUN NGT. DURING THIS
TIMEFRAME...THE REGION WILL SEE WIND REGIME START OUT NORTHERLY
OVER THE ENTIRE CWA AND SHIFT TO THE NW BY SATURDAY AFTERNOON
RIGHT INTO SUNDAY. THIS EFFECT WILL HAVE LGT SW OVER THE AREA WITH
MAIN FOCUS OVER NORTHERN ZONES...TO MORE OF UPSLOPE/HIR ELEV
SCENARIO AS THOSE NW WINDS KICK IN. BEST CHANCE FOR ANY LGT ACCUM
WILL BE DURING THIS TIME. BY SUN NGT...SFC LOW OVER SOUTHERN
QUEBEC AND WINDS BEGIN TO TAPER OFF. EARLY MON MORNING...AN UPPER
LEVEL LOW PUSHES THRU THE GREAT LKS REGION AND INTO WESTERN NY BY
MON AFTNOON. MDLS BRING THIS LOW ACROSS THE GOING INTO MON NGT.
THIS WILL GIVE A BROAD LL CLD BASE WITH LGT PRECIP TO END OFF THE
EXTENDED. THESE CLDS THAT ARE EXPECTED FOR THE DURATION WILL
ASSIST IN STABILIZING TEMPS...ESPECIALLY AT NGT...BY NOT ALLOWING
RADIATIONAL COOLING. SO AS A RESULT...STAYED NEAR MDL GUIDANCE FOR
HIGHS AND TWEAKED A DEGREE OR SO UP FOR OVERNGT LOWS.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...VIS SATL PIC SHOWS LOW CLOUDS QUICKLY
DISSIPATING ACRS CENTRAL/NORTHERN VT AS WELL AS NORTHERN NY THIS
AFTN. SHORT TERM AVIATION CHALLENGE WL BE AMOUNT OF CLOUDS THRU
TONIGHT AND POTENTIAL FOR LIGHT SNOW ON WEDS. MAINLY VFR
CONDITIONS WL PREVAIL THRU THIS EVENING...WITH SFC RIDGE IN
PLACE...BUT SOUNDINGS SHOW LLVL MOISTURE INCREASING BTWN 03-06Z
TONIGHT. THIS MOISTURE WL CAUSE CIGS TO LOWER AND PRODUCE SOME MVFR
CONDITIONS AT MOST TAF SITES BTWN 07-10Z. STILL SOME QUESTIONS
WITH REGARDS TO NORTHERN EDGE OF LIGHT SNOW WEDS ACRS OUR CWA.
LATEST TRENDS SUGGEST SOME -SN DEVELOPING BTWN 12-14Z MAINLY ALONG
AND SOUTH OF A MSS TO PBG TO 1V4 LINE. WL PLACE 3-4SM -SN FOR
RUT/MPV/SLK/MSS BY 14Z WEDS...WITH VCSH AT BTV/PBG. FEEL
DEVELOPING NORTHERLY FLW AND CPV CONVERGENCE WL PRODUCE SOME -SN
AT BTV BY 18Z WEDS...WITH MVFR TO IFR CONDITIONS POSSIBLE THRU THE
AFTN AT MOST STIES.

OUTLOOK 18Z WEDNESDAY THROUGH SATURDAY...
18Z WEDNESDAY THROUGH 12Z THURSDAY...MVFR WITH OCCASIONAL VFR IN
AREAS OF SNOW SHOWER. 12Z THURSDAY THROUGH SAT...MAINLY VFR WITH OCCASIONAL
MVFR IN -SHSN ESPECIALLY AT MPV/SLK.

&&

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

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...JN
AVIATION...TABER