FXUS61 KBTV 250628
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
128 AM EST FRI DEC 25 2009

.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL SHIFT EASTWARD ACROSS NORTHERN NEW 
YORK TONIGHT AND ACROSS NEW ENGLAND ON CHRISTMAS DAY. MOISTURE 
TRAPPED IN SOME VALLEY LOCATIONS WILL PRODUCE VARIABLY CLOUDY 
CONDITIONS DURING THE PERIOD...BUT PRECIPITATION IS NOT EXPECTED. A 
FRONTAL SYSTEM ARRIVES SATURDAY MORNING WITH MIXED WINTRY 
PRECIPITATION OVERSPREADING NORTHERN NEW YORK EARLY SATURDAY AND 
THEN VERMONT LATER IN THE DAY. SIGNIFICANT SLEET AND FREEZING RAIN 
IS POSSIBLE ACROSS NORTHERN NEW YORK WITH THIS SYSTEM...WITH LIGHTER 
ACCUMULATIONS OF SLEET OR ICE ELSEWHERE ACROSS THE NORTH COUNTRY
SATURDAY AND SATURDAY NIGHT.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 900 PM EST THURSDAY...OVERALL FCST IN GREAT SHAPE THIS
EVENING...WITH ONLY TWO MINOR ADJUSTMENTS NEEDED.
FIRST...INCREASED THE RANGE IN TEMPS...BASED ON EXPECTED CLOUD
COVER IN SOME AREAS AND LIMITED CLOUDS IN OTHERS. IN
ADDITION...MENTIONED PATCHY FZFG...GIVEN CRNT OBS SHOWING 1/2SM AT
SLK WITH FZFG ALREADY AND OTHER LOCATIONS REPORTING 2 TO 4 SM IN
BR. SOUNDINGS SHOW PLENTY OF LLVL MOISTURE ACRS OUR CWA...AND
COMBINED WITH LIGHT WINDS...EXPECT AREAS OF FZFG TO
DEVELOP...ESPECIALLY IN DEEPER VALLEY REGIONS. OTHERWISE...GIVEN
DEPTH OF MOISTURE...HIGHER SUMMITS MAY SEE MAINLY CLR SKIES
TONIGHT. THE AMOUNT OF CLRING WL PLAY A BIG ROLE IN DETERMINING
OVERNIGHT LOWS...WITH TEMPS RANGING FROM NEAR 10F IN CLR LOCATIONS
TO M/UPPER 20S WHERE CLOUDS PREVAIL. OTHERWISE...REST OF FCST IN
EXCELLENT SHAPE TONIGHT.

PREVIOUS FORECAST DISCUSSION BELOW...
SHARP TEMPERATURE INVERSIONAROUND 1500 FEET AND LIGHT WIND FIELDS
HAVE HELPED TO TRAP CLOUDINESS ACROSS MOST VALLEY LOCATIONS...WITH
WARMER CONDITIONS AND SUNNY SKIES ACROSS THE SUMMITS AND HIGHER
TERRAIN THIS AFTERNOON. LITTLE OVERALL CHANGE TONIGHT AS RIDGE
AXIS CRESTS OVERHEAD. BREAKS IN THE OVERCAST ACROSS THE NRN
ADIRONDACKS MAY LEAD TO SUFFICIENT RADIATIONAL COOLING FOR SOME
PATCHY FOG LATER THIS EVENING AND OVERNIGHT. ELSEWHERE...ENOUGH
LOW CLOUD COVER TO PRECLUDE MUCH IN THE WAY OF FOG. CAN/T RULE OUT
A BIT OF FREEZING DRIZZLE OR FINE SNOW FLURRY ACTIVITY IN THE
VALLEYS TONIGHT WITH LOW CLOUD DECK...BUT NO MEASURABLE PCPN
EXPECTED. LOWS WILL GENERALLY RANGE FROM 10-15F IN THE NRN
ADIRONDACKS AND NORTHEAST KINGDOM...AND IN THE UPPER TEENS TO
LOWER 20S ELSEWHERE. LOWS COULD BE A TAD HIGHER IN THE OUTLYING
SPOTS IF CLOUDS ARE A BIT MORE WIDESPREAD THAN CURRENTLY FORECAST.

CHRISTMAS DAY LOOKS FAIR AND DRY WITH HIGHS IN THE LOW TO MID 30S AS 
SFC RIDGE AXIS SHIFTS EWD ACROSS NEW ENGLAND. VALLEYS START CLOUDY 
IN THE MORNING WITH INVERSION STILL IN PLACE BETWEEN 1000-2000 FT. 
PERHAPS A FEW MORE BREAKS IN THE CHAMPLAIN VALLEY TOMORROW...BUT 
MAINLY IN THE AFTERNOON WITH SOME MIXING POTENTIAL. WINDS WILL BE 
LIGHT FROM THE EAST/SOUTHEAST DURING THE DAYLIGHT HRS.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 407 PM EST THURSDAY...AN OCCLUDED FRONT WILL LIFT NORTHEASTWARD 
ACROSS THE REGION WITH MIXED PRECIPITATION BEGINNING ACROSS NRN
NY DURING THE PRE-DAWN HOURS SATURDAY....AND THEN GRADUALLY
OVERSPREADING VT DURING THE DAY ON SATURDAY. THE MIXED
PRECIPITATION WILL GENERALLY BE OF LIGHT TO OCCASIONALLY MODERATE
INTENSITY. GREATEST QPF SHOULD BE ACROSS THE ST. LAWRENCE RIVER
VALLEY WITH LIQUID EQUIVALENT AMTS OF A QUARTER TO HALF INCH. WITH
COLD NELY DRAINAGE WINDS...THE ST. LAWRENCE VALLEY HAS THE BEST
CHANCE OF SEEING PROLONGED FREEZING RAIN DURING SATURDAY...AND
WILL PROBABLY SEE THE GREATEST IMPACT IN TERMS OF ICY ROAD
CONDITIONS. A QUARTER INCH OF ICE PLUS SOME SLEET ACCUMULATION IS
EXPECTED. WE HAVE POSTED A WINTER STORM WATCH FOR ST.
LAWRENCE...FRANKLIN...AND WRN CLINTON COUNTIES FOR SLEET/FREEZING
RAIN POTENTIAL DURING SATURDAY AND SATURDAY NIGHT. ELSEWHERE...LOW-
LEVEL WARMING YIELDS SLEET CHANGING TO RAIN IN THE CHAMPLAIN
VALLEY...PORTIONS OF THE NRN ADIRONDACKS AND THE VALLEYS OF
RUTLAND AND WINDSOR COUNTIES. ADDITIONAL SLEET/ZR THREAT EAST OF
THE GREENS IN ERN/NERN VT EXISTS SATURDAY AND SATURDAY NIGHT...BUT
QPF IS A BIT LIGHTER IN MOST MODEL GUIDANCE ACROSS VT AND PCPN
SHOULD BE INTERMITTENT DUE TO SHADOWING EFFECTS WITH SELY LOW-
LEVEL FLOW. ALSO...WITH LATER ONSET TIME...WILL HOLD OFF ON ANY
HEADLINES FOR VERMONT AT THIS TIME...BUT SOME LIGHT ICE
ACCUMULATION IS POSSIBLE EAST OF THE GREENS WITH TEMPS IN THE
LOWER 30S FOR DAYTIME HIGHS. PRECIP WINDS DOWN AS OCCLUSION PASSES
SATURDAY NIGHT.

WINDS: GUSTY SOUTHEASTERLY WINDS WILL DEVELOP ALONG THE WESTERN 
SLOPES OF THE GREEN MTNS DURING SATURDAY MORNING AND PERSIST INTO 
THE AFTERNOON/EARLY EVENING HOURS. THESE WINDS WON/T BE TO THE 
MAGNITUDE OF THE DEC 9TH STORM...BUT SELY GUSTS TO 40-45 MPH ARE 
POSSIBLE. THIS MAY RESULT IN ISOLATED/LOCALIZED 
POWER OUTAGES SATURDAY FOR THE WEST SLOPE COMMUNITIES FROM RUTLAND 
TO SOUTH LINCOLN TO CAMBRIDGE ASSOCIATED WITH ANY DAMAGE TO 
POWERLINES OR TREE BRANCHES. HAVE INCLUDED WIND POTL IN UPDATED HWO. 
MAY NEED A WIND ADVISORY FOR THE WEST SLOPES OF THE GREEN MTNS AS 
EVENT APPROACHES. WILL CONTINUE TO MONITOR POTL.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 324 PM EST THURSDAY...AS AFOREMENTIONED OCCLUSION LIFTS THROUGH 
THE AREA SUNDAY MORNING...WILL MAINTAIN WIDSPREAD RAIN AND/OR
MIXED PCPN ACROSS THE AREA...ESP NORTH AND EAST. THIS WILL TEND TO
TAPER OFF TO SCT SHSN BY THE AFTERNOON HOURS AS SFC COLD FRONT
SWEEPS EASTWARD ACROSS THE AREA. WITH STRONG COLD AIR ADVECTION
DEVELOPING THROUGH THE LOWER TO MID LVLS THROUGH TIME...MAX TEMPS
SHOULD OCCUR EARLY IN THE DAY WITH VALUES HOLDING STEADY OR SLOWLY
FALLING DURING THE AFTERNOON UNDER BRISK WESTERLY FLOW. BY SUNDAY
NIGHT...MOSTLY CLOUDY CONDS CONTINUE ALONG WITH SCT SHSN...ESP IN
FAVORED SNOW BELTS TO THE LEE OF LK ONTARIO WHERE SOME MINOR ACCUM
POSSBL.

BY MONDAY MEAN FLOW BEGINS TO BACK TO SOUTHWESTERLY AHEAD OF UPPER 
TROUGH AND ATTENDANT ARCTIC FRONT DIGGING SHARPLY SOUTHEASTWARD 
TOWARDS THE REGION. EXPECT A BROAD INCREASE IN CLOUD COVER THROUGH 
THE DAY WITH MAINLY DRY CONDS EXPECTED ACROSS VT...THOUGH MORE 
PRONOUNCED ACTIVITY ACROSS NRN NY WHERE BANDS OF LAKE EFFECT SNOW 
LIKELY TO BACK NORTHWARD INTO ST LAW/FRANKLIN COUNTIES WITH SOME 
DECENT ACCUM POSSBL. ARCTIC BNDRY THEN CROSSES THE REGION MONDAY 
EVENING/NIGHT WITH CONTINUED SHSN/POSSBL SQALLS AND SHARPLY FALLING 
TEMPS ON THE HEELS OF GUSTY NWRLY WINDS. TEMPS TO BOTTOM OUT IN THE 
SINGLE DIGITS MANY LOCALES WITH SOME MARGINAL WIND CHILL CONCERNS 
POSSBL IN FAVORED COLDER SPOTS/HIGHER TERRAIN.

BY TUESDAY TEMPS TO ESSENTIALLY GO NOWHERE...STRUGGLING UPWARD ONLY 
INTO THE UPPER SINGLE DIGITS AND/OR TEENS AS WINDS SLOWLY ABATE 
THROUGH TIME. REST OF WORK WEEK FAIRLY QUIET AS SFC HIGH PRESSURE 
BUILDS EASTWARD ATOP THE REGION. LOOK FOR TEMPS TO SLOWLY MODERATE 
THROUGH THE PERIOD THOUGH REMAIN AROUND 5 DEG OR SO BELOW LATE DEC 
NORMS.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...GENERALLY IFR/LIFR CONDITIONS WILL PERSIST
THROUGH 12Z FRIDAY. A STRONG LOW LEVEL INVERSION AND AMBIENT
MOISTURE WILL ALLOW LOW CLOUDS TO HANG TOUGH ACROSS THE REGION
THROUGH MUCH OF THE PERIOD. WINDS ARE LIGHT UNDER HIGH PRESSURE.
AREAS OF FOG ARE ALSO POSSIBLE THROUGH ABOUT 14Z. MOST LOCATIONS
WILL SLOWLY SEE CEILINGS IMPROVE TO MVFR BETWEEN 14Z-18Z. LOW
CLOUDS WILL BEGIN TO LIFT/ERODE TOWARD THE END OF THIS FCST CYCLE.

OUTLOOK...06Z SATURDAY THROUGH TUESDAY...

06Z SAT THRU 12Z SAT...MAINLY VFR. HIGH PRESSURE WILL BE EXITING
THE REGION. SOME LIGHT MIXED PRECIPITATION IS POSSIBLE TOWARD 12Z
AT KMSS.

12Z SAT THRU 12Z SUN...VFR W/OCNL MVFR/IFR IN MIXED PCPN AS
OCCLUDED FRONT CROSSES AREA. GUST SOUTHEAST WINDS.

12Z SUNDAY THRU 12Z MONDAY...MAINLY VFR EXCEPT OCNL MVFR IN MTN
SHSN...ESPECIALLY AT KSLK/KMPV.

12Z MONDAY THRU 12Z TUE...VFR TRENDING MVFR/IFR IN SHSN/SQ AS UPPER
LOW AND STRONG COLD FRONT AFFECT THE REGION. GUSTY NORTHERLY WINDS
DEVELOPING AFTER 06Z TUE.

12Z TUE THRU 00Z WED...MAINLY VFR WITH SCT MVFR IN MTN SHSN...MAINLY 
AT THE KSLK TERMINAL. GUSTY NORTHERLY WINDS.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE SATURDAY 
     NIGHT FOR NYZ026-027-029>031-087.

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/TABER
SHORT TERM...BANACOS
LONG TERM...JMG
AVIATION...RJS