FXUS61 KBTV 291949
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
249 PM EST SUN NOV 29 2009
.SYNOPSIS...
A WAVE OF LOW PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL
TRACK NORTHEASTWARD ACROSS FAR NORTHERN NEW YORK AND VERMONT
OVERNIGHT. THIS SYSTEM WILL BRING WIDESPREAD LIGHT RAIN...WITH A
CHANCE FOR POCKETS OF FREEZING RAIN LATE TONIGHT ACROSS FAR
NORTHEASTERN VERMONT. AS THE LOW PASSES TO THE EAST...A COLD FRONT
WILL SWEEP SOUTHEASTWARD ACROSS THE REGION WITH PRECIPITATION ENDING
AS A BRIEF PERIOD OF SNOW SHOWERS. SNOW SHOWERS MAY LINGER INTO THE
AFTERNOON HOURS ACROSS THE HIGHER SUMMITS. THE NEXT CHANCE OF
POTENTIALLY HEAVY PRECIPITATION ARRIVES WITH A STRONGER LOW PRESSURE
SYSTEM MOVING NORTHWARD FROM THE GULF COAST STATES LATE WEDNESDAY
NIGHT INTO THURSDAY. AT THIS TIME...AN INLAND TRACK OF THE LOW IS
FAVORED AS IT MOVES NORTHWARD ACROSS THE NORTHEASTERN UNITED
STATES. THIS SHOULD RESULT IN MOSTLY RAIN ACROSS THE NORTH
COUNTRY...WITH A CHANCE FOR SNOW SHOWERS AS THE LOW PASSES
THURSDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 245 PM EST SUNDAY...A NORTHERN STREAM SHORTWAVE TROUGH ACROSS THE
GREAT LAKES REGION AND ATTENDANT 1004MB SFC LOW NEAR DETROIT
MICHIGAN WILL BRING AN INCREASING THREAT FOR WIDESPREAD LIGHT RAIN
ACROSS THE NORTH COUNTRY OVERNIGHT AS THIS SYSTEM MOVES ENEWD.
LOW-LEVEL WAA IN THE 850-700MB LAYER GRADUALLY INCREASES THIS
EVENING BRINGING INCREASING CLOUDS. GENERALLY FOLLOWED 3-HRLY SREF
POPS WHICH SUGGEST BEST ASCENT REMAINS ACROSS ST.
LAWRENCE/FRANKLIN NY COUNTIES THRU 03Z. THEREAFTER...RAINFALL
GRADUALLY SPREADS EWD ACROSS THE CHAMPLAIN VLY BETWEEN
03-06Z...AND THEN INTO CENTRAL/ERN VT MAINLY AFTER 06Z. WHILE
THERMAL PROFILES GENERALLY SUPPORT RAIN OVERNIGHT...A FEW POCKETS
OF FREEZING RAIN ARE POSSIBLE...MAINLY EAST OF THE GREEN MTNS IN
THE SHELTERED VALLEYS OF N-CENTRAL AND NERN VT. DEWPOINTS IN THESE
AREAS ARE GENERALLY IN THE UPR 20S/AROUND 30...AND SOME COOLING
WITH ONSET OF PCPN WILL BRING NEAR-SFC CONDITIONS CLOSE TO
FREEZING. DON/T BELIEVE ZR WILL BE A PREDOMINANT P-TYPE...SO HAVE
INCLUDED AS A CHANCE OF FREEZING RAIN GIVEN MARGINAL SFC
TEMPERATURES. IN TERMS OF QPF...BEST FORCING IS ACROSS NRN CWA AND
HAVE INDICATED UP TO THREE TENTHS OF AN INCH OF RAINFALL ALONG THE
INTL BORDER THRU 12Z MONDAY...AND ONLY A FEW HUNDREDTHS ACROSS
S-CENTRAL VT. WINDS WILL GENERALLY BE LIGHT FROM THE
SOUTH/SOUTHWEST...EXCEPT BCMG NWLY AROUND 10 KTS AFT 09Z WITH COLD
FRONT BEGINNING TO MOVE ACROSS THE ST. LAWRENCE VALLEY AS THE SFC
LOW PASSES TO THE EAST TOWARD DAYBREAK. SOME WET SNOW MAY BEGIN TO
MIX IN WITH THE RAIN ACROSS THE ST. LAWRENCE VALLEY 09-12Z
MONDAY...BUT PCPN SHOULD BE WINDING DOWN IN THE SLV AT THAT
TIME.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 245 PM EST SUNDAY...LOW PRESSURE ALONG SFC FRONTAL BOUNDARY BEGINS
TO PULL AWAY FROM THE REGION MID TO LATE MORNING MONDAY ACROSS
MAINE ALLOWING FOR SFC COLD FRONT AND MODERATELY STRONG CAA TO
MOVE SEWD ACROSS ENTIRE CWA BY 18Z MONDAY. LOOKING FOR BEST QG
ASCENT TO SHIFT EAST OF THE CT RIVER VALLEY AFT
15Z...HOWEVER...SCATTERED RAIN/SNOW SHOWER ACTIVITY WILL CONTINUE
FOR A BRIEF TIME FOLLOWING THE FRONTAL PASSAGE UNTIL BOUNDARY
LAYER DRIES. UPSLOPE FLOW COMPONENT SHOULD KEEP SNOW SHOWERS GOING
ACROSS THE CENTRAL/NRN GREENS AND NRN ADIRONDACKS THROUGH AT LEAST
EARLY AFTN. BECAUSE SFC TEMPERATURES WILL BE NEAR FREEZING IN THE
VALLEYS...ONLY EXPECTING A DUSTING TO AN INCH ACROSS NRN NY AND
GENERALLY LITTLE OR NO ACCUMULATION IN THE CHAMPLAIN VALLEY AND
POINTS SOUTH AND EAST. ACROSS THE MTNS...AN INCH OR TWO IS
POSSIBLE WITH SNOW SHOWER ACTIVITY DURING THE MORNING/EARLY
AFTN...ESPECIALLY FOR THE HIGHER SUMMITS OF CENTRAL/NRN VT. HIGH
TEMPERATURES MONDAY WILL GENERALLY BE IN THE MID 30S ACROSS NRN NY
WHERE CAA ARRIVES FIRST...AND IN THE UPR 30S ACROSS THE CHAMPLAIN
VALLEY. LOW/MID 40S ARE LIKELY IN PLACE ACROSS THE SRN VALLEYS
DURING THE MORNING...WITH TEMPS STEADY OR SLOWLY FALLING AS 850MB
TEMPS DROP TO -6C TO -8C BY LATE AFTN.
NO SIGNIFICANT WX IS EXPECTED DURING THE MONDAY NIGHT THROUGH
TUESDAY NIGHT. A WEAKENING UPR TROUGH IN NWLY 500MB FLOW WILL
BRING VARIABLY CLOUDY SKIES MONDAY NIGHT WITH PERIODS OF MID-LVL
CLOUDS ANTICIPATED. SFC RIDGE AXIS WILL BRING LIGHT WINDS BUT
CLOUDS SHOULD LIMIT RADIATIONAL COOLING TO SOME DEGREE. LOW TEMPS
WILL GENERALLY RANGE FROM THE LOW TO MID 20S...WITH A FEW UPR
TEENS POSSIBLE ACROSS THE NRN ADIRONDACKS AND NERN VT. A MORE
SIGNIFICANT RIDGE WILL BUILD ACROSS THE REGION TUESDAY INTO
TUESDAY NIGHT WITH RISING HGTS ALOFT. LOOKING FOR SEASONABLE HIGHS
ON TUESDAY - GENERALLY IN THE MID TO UPR 30S...WITH LOWS TUESDAY
NIGHT IN THE LOW TO MID 20S. SURFACE WINDS WILL GENERALLY BE
LIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 225 PM EST SUNDAY... VERY ACTIVE PERIOD EXPECTED FOR THE
EXTENDED FORECAST WITH POTENTIAL FOR A SIGNIFICANT STORM WEDS
NIGHT INTO THURSDAY. TRANQUIL DAY ON TAP FOR WEDNESDAY ACROSS THE
NORTH COUNTRY WITH GENERALLY PARTLY SUNNY SKIES AND SLIGHTLY ABOVE
NORMAL TEMPS IN THE LOWER 40S. MEANWHILE...SURFACE LOW DEVELOPING
ALONG THE GULF COAST WILL SET THE STAGE FOR A SIGNIFICANT STORM
ACROSS THE NORTHEAST WEDNESDAY NIGHT INTO THURSDAY. LATEST
GFS/ECMWF AND ENSEMBLES FAIRLY CLOSE IN REGARDS TO SURFACE
TRACK...WHICH HAS THE LOW RIDING NORTHEAST ALONG THE APPALACHIAN
MOUNTAINS AND DIRECTLY OVER THE BTV CWA ON THURSDAY. THIS TRACK IS
NOT VERY FAVORABLE FOR SNOW WHERE MID AND LOW LEVEL TEMPS WELL
ABOVE FREEZING...MEANING MAINLY A RAIN EVENT. IMPRESSIVE PW'S OFF
THE GFS OF 1.25 INCHES INDICATE THIS COULD BE A HEAVY RAIN EVENT
AS WELL...WITH MEAN QPF FIELDS AMONG ALL MODELS SHOWING AT LEAST
3/4 INCH...POSSIBLY UP TO 1.25 INCHES. WITH RECENT RAINFALL AND
THE TIME OF YEAR WHERE MOST RAINFALL GOES INTO RUNOFF...I DON'T
THINK WE COULD HANDLE TOO MUCH MORE RAIN...SO THIS SITUATION WILL
NEED TO BE CLOSELY MONITORED OVER THE NEXT FEW DAYS FOR FLOOD
POTENTIAL.
STORM BEGINS TO EXIT THE REGION LATE THURSDAY AFTERNOON AND
NIGHT...USHERING MUCH COLDER AIR ACROSS THE REGION. ANY LEFTOVER
PRECIPITATION WILL LIKELY CHANGEOVER TO SNOW...THOUGH SHOULD BE
LIGHT AS LOW LEVEL MOISTURE BEGINS TO DIMINISH OVERNIGHT. FRIDAY
THROUGH SATURDAY THE ASSOCIATED UPPER TROUGH REMAINS OVER THE REGION
WITH SEVERAL WEAK SHORTWAVES MOVING THROUGH THE UPPER FLOW...WHICH
WILL CONTINUE THE CHANCE FOR SNOW SHOWERS. QUIET WEATHER EXPECTED AT
THIS TIME FOR SUNDAY...THOUGH THE CHANCE FOR SNOW SHOWERS WILL STILL
EXISTS AS A WEAK COLD FRONT TRACKS NORTH ALONG THE CANADIAN BORDER.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...GENERALLY VFR CONDITIONS EXPECTED FOR THE
REST OF SUNDAY WITH BKN-OVC MID LEVEL CLOUDS. LATE THIS EVENING
INTO SUNDAY NIGHT MVFR DECK WILL BE FILTERING IN FROM THE WEST
AHEAD OF AN APPROACHING COLD FRONT. PRECIPITATION WILL START AS
RAIN AT KMSS AROUND 02Z...REACHING THE CHAMPLAIN VALLEY EASTWARD
BY 06Z. MVFR CIGS/VSBY IN RAIN WILL THEN CONTINUE THROUGH 12Z
BEFORE RAIN BEGINS TO MIX AND CHANGE TO SNOW...MAINLY FROM KBTV
WEST. CHANGEOVER TO SNOW FOR KRUT/KMPV LIKELY TO BE CLOSER TO 16-18Z.
OUTLOOK 18Z MONDAY THROUGH THURSDAY...
18Z MON THRU 00Z WEDS...SCATTERED MVFR SNOW SHOWERS POSSIBLE.
00Z WED THRU 00Z THU...VFR.
00Z THU THRU 00Z FRI...MVFR/IFR RAIN/SNOW AND GUSTY WINDS LIKELY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...LAHIFF
AVIATION...LAHIFF
