FXUS61 KBTV 300201
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
901 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 900 PM EST SUNDAY...RAIN HAS BEGUN TO MOVE INTO WESTERN
SECTIONS OF THE FORECAST AREA AS A SURFACE LOW SLIDES EAST ACROSS
THE GREAT LAKES. ALTHOUGH RADAR IS INDICATING LIGHT RAIN SHOWERS
ACROSS PORTIONS OF THE ADIRONDACKS AND SAINT LAWRENCE RIVER
VALLEY...THE BULK OF THE PRECIPITATION IS JUST NOW MOVING ACROSS
LAKE ONTARIO AND WILL ENTER THE FORECAST AREA LATER THIS EVENING.
TEMPERATURES HAVE BEEN HOLDING FAIRLY STEADY OR EVEN RISING A
DEGREE OR TWO THIS EVENING. THERE IS STILL THE POSSIBILITY OF SOME
LIGHT FREEZING RAIN IN THE NORTHEAST KINGDOM WHERE TEMPERATURES
ARE HOVERING AT OR JUST BELOW FREEZING...32 AT ISLAND POND...30 AT
WALDEN...AND 30 AT GALLUP MILLS. HAVE ISSUED AN UPDATE TO ADJUST
TEMPERATURES CLOSER TO CURRENT TRENDS AND TO FRESHEN WORDING.
OTHERWISE...THE GOING FORECAST LOOKS GOOD AND NO OTHER CHANGES ARE
NEEDED.
PREVIOUS DISCUSSION...
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 SUNDAY/...
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 /02Z MONDAY THROUGH FRIDAY/...
THROUGH 00Z TUESDAY...A LARGE AREA OF CLOUDS AND PRECIPITATION
WILL MOVE INTO THE REGION LATER TONIGHT THROUGH EARLY MONDAY
MORNING AS A LOW PRESSURE SYSTEM MOVES INTO THE NORTHEAST UNITED
STATES. VFR CONDITIONS AT THE START OF THE PERIOD WILL BECOME MVFR
WITH RESPECT TO CEILINGS AS CLOUDS LOWER TO THE 1500 TO 2500 FOOT
RANGE. VISIBILITIES WILL REMAIN IN THE VFR CATEGORY...BUT WILL
LOWER AT TIMES INTO THE MVFR CATEGORY. A WIND SHIFT WILL OCCUR
JUST AFTER 12Z WITH WINDS BECOMING NORTHWEST AND ANY RAIN CHANGING
OVER TO SOME SNOW BEFORE ENDING BY 17Z. VFR CONDITIONS ARE
EXPECTED AFTER 17Z THROUGH THE END OF THE PERIOD.
OUTLOOK 00Z TUESDAY THROUGH THURSDAY...
00Z TUE 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/MB
SHORT TERM...BANACOS
LONG TERM...LAHIFF
AVIATION...EVENSON/LAHIFF
