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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 100824
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
324 AM EST WED FEB 10 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 TONIGHT/...
AS OF 850 PM EST TUESDAY...
THE FORECAST IF VERIFYING QUITE WELL TONIGHT. WHILE SOME LOW
CLOUDS STILL REMAIN ON THE VERY NORTHEAST TIP OF ESSEX COUNTY
VT...MUCH OF NORTHERN VT AND THE NEK HAVE MOSTLY CLEAR SKIES. THIS
IS ALLOWING TEMPS TO DROP A BIT FASTER IN THE NORTHEAST
KINGDOM. SO...THE UPDATE TO THE GRIDS IS TO LOWER OVERNIGHT LOWS
THERE INTO THE SINGLE DIGITS. HIGH THIN CLOUDS IN ADVANCE OF THE
APPROACHING OHIO VALLEY SYSTEM ARE SPREADING INTO THE ST LAWRENCE
VALLEY OF NEW YORK...AND HAVE ADJUSTED SKY COVER IN POINTS WEST UP
TO REFLECT THIS TREND. NO OTHER CHANGES AT THIS TIME.

FROM PREVIOUS DISCUSSION...
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 TROUGH 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 /THURSDAY THROUGH FRIDAY/...
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 NIGHT THROUGH TUESDAY/...
-- Changed Discussion --
AS OF 324 AM EST WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
OVER THE PAST SEVERAL MODEL RUNS HAS CONTINUED TO STAY CONSISTENT
IN REGARDS TO BROAD LOW PRESSURE COMPLEX OVER CANADIAN MARITIMES/
EASTERN CANADA. THIS WILL HAVE SETUP FOR NNW WIND FLOW OVER THE
ENTIRE CWA FOR MUCH OF THE FORECAST PERIOD. EMPHASIS ON
PRECIPITATION CONTINUES TO REMAIN OVER NORTHERN PORTIONS OF THE
AREA...WITH FOCUS SHIFTING FROM ZONES TO HIR ELEV AREAS DUE TO
SHIFT IN WINDS FROM N TO MORE NW. THIS WILL ALLOW UPSLOPE EFFECTS
TO CONCENTRATE HIR QPF TOTALS FOR POTENTIAL FOR ACCUMULATING
SNOWFALL. SUN NGT INTO TUES...SLIGHT SHIFT IN WX PATTERN AS WINDS
SLACKEN OVER THE REGION WITH APPROACH OF LOW MVG THRU THE OHIO
VALLEY. WK RIDGING DEVLEOPS BRIEFLY AS THIS SYSTEM PUSHES ENE INTO
THE NORTHEAST CORRIDOR. SOME MDL DISCREPANCIES ON TRACK ATTM...BUT
DO EXPECT CLD COVER TO REMAIN OVER AREA DESPITE RIDGING...AND WILL
SHOW INCR POPS FOR LGT SNOW OVER AREA AS OHIO VALLEY LOW SPINS
THRU THE AREA AND OUT TO SEA BY TUESDAY NGT. CWA RETURNS TO WK NNW
FLOW BEHIND THIS...SO WILL KEEP SL CHANCE FOR --SW. EXTENSIVE CLD
COVER THRU FORECAST WILL KEEP TMEPS IN CHECK SO WILL STAY CLOSE TO
MDL GUIDANCE NUMBERS.
-- End Changed Discussion --

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...REGION WILL SEE A MIX OF COND THRU FORECAST
PERIOD AS WINTER STORM PUSHES EAST THRU THE MID ATLANTIC REGION.
FORECAST SITES WILL SEE A VFR SHIFT DOWN TO IFR CEILINGS AND VSBY
IN ANY DEVLEOPING SNOW SHOWERS DROPPING DOWN TO 2-6SM AT TIMES.
THE LWR VALUES WILL BE CONCENTRATED NEAR RUT/MPV AS THEY ARE
CLOSET TO APPROACHING STORM. THE LATTER HALF OF THE FORECAST WILL
SEE GRADUAL IMPROVEMENT IN CEILINGS/VSBY FROM W TO E AS STORM
SYSTEM MVS AWAY FROM THE NORTHEAST. WINDS WILL VARY FROM SSE TO
THE N FROM 5 TO 15KTS

OUTLOOK 06Z THURSDAY THROUGH SATURDAY...
06Z 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.

&&

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

&&

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