FXUS61 KBTV 150810
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
310 AM EST TUE DEC 15 2009
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL MOVE EAST FROM THE WESTERN GREAT
LAKES OVERNIGHT...AND WILL BE OVER THE SAINT LAWRENCE VALLEY
TUESDAY MORNING. THIS LOW WILL BRING AN ARCTIC COLD FRONT THROUGH
THE REGION ON TUESDAY...BRINGING MUCH COLDER AIR TO THE NORTH COUNTRY
WEDNESDAY AND THROUGH THE REMAINDER OF THIS WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1149 PM EST MONDAY...NEAR TERM UPDATE TO FURTHER MODIFY
OVERNIGHT PRECIPITATION TYPE AND TEMPERATURE FORECAST BASED ON
CURRENT TRENDS TO INCLUDE RAIN AND SNOW SHOWERS IN THE CHAMPLAIN
AND ST LAWRENCE VALLEYS...AND ALSO POTENTIAL FOR SLEET MAINLY IN
SE VT.
FROM PREVIOUS DISCUSSION...
FOR TONIGHT...PRECIPITATION ASSOCIATED WITH A WEAK AREA OF LOW
PRESSURE MOVING THROUGH THE LOWER GREAT LAKES HAS BLOSSOMED OVER
NORTHERN NEW YORK..AND WILL BE PROGRESSING EASTWARD OVERNIGHT.
HAVE BUMPED POPS TO LIKELY ACROSS MUCH OF THE AREA DUE TO THIS.
PTYPE WILL BE VERY TRICKY WITH THIS SYSTEM AS MODELS STRUGGLE TO
HANDLE MID LEVEL WARMING AT 925 MB THIS EVENING. LATEST RUC13 HAS
THE BEST HANDLE ON THIS SO HAVE LEANED TOWARDS THIS SCENE RIO.
LATEST LAPS ANALYSIS SHOWS ABOVE FREEZING 925 MB LAYER PUSHING
INTO SOUTHWESTERN NEW YORK AT THIS TIME...AND SHOULD PROGRESS
NORTHEASTWARD OVERNIGHT. AT THE SAME TIME...SURFACE OBS SHOW SAINT
LAWRENCE AND CHAMPLAIN VALLEYS MAINLY ABOVE FREEZING...WITH
EVERYWHERE ELSE BELOW. INITIALLY...PRECIP ACROSS NORTHERN NEW YORK
SHOULD FALL AS RAIN IN THE SLV AND SNOW ACROSS THE DACKS...BUT AS
THE MID LEVEL WARM LAYER MOVES EAST...PRECIP ACROSS THE DACKS WILL
BECOME A MIX OF SNOW AND FREEZING RAIN. EASTWARD ACROSS THE
CHAMPLAIN VALLEY...PRECIP SHOULD BE RAIN IN THE CVL WITH MAINLY
SNOW AND POCKETS OF FREEZING RAIN ELSEWHERE OVERNIGHT.
ON TUESDAY...WHILE MOISTURE ASSOCIATED WITH THIS SYSTEM BEGINS TO
TAPER OFF...THE CHANCE FOR PRECIPITATION WILL PERSIST THROUGH THE
DAY. PTYPE WILL MAINLY BE RAIN OR SNOW...THOUGH THE POTENTIAL FOR
POCKETS OF FREEZING RAIN WILL STILL EXIST IN THE MORNING ACROSS
PORTIONS OF NORTHERN VERMONT WHERE MID LEVEL TEMPS REMAIN WARM AND
SURFACE TEMPS ARE BELOW FREEZING. BY AFTERNOON 925 MB TEMPS RETURN
BELOW FREEZING WITH ANY LEFTOVER PRECIP BEING RAIN OR
SNOW...DEPENDING ON SURFACE TEMPS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 444 PM EST MONDAY...WILL KEEP IN A SLIGHT CHANCE OF SNOW
SHOWERS TUESDAY NIGHT...WITH SKIES CLEARING LATE TUESDAY NIGHT.
VERY COLD TEMPERATURES WILL MOVE INTO THE REGION ON WEDNESDAY WITH
HIGHS IN THE TEENS TO LOWER 20S. GUSTY NORTHWEST WINDS WILL
DEVELOP ACROSS THE REGION WEDNESDAY AND CONTINUE INTO WEDNESDAY
NIGHT. SOME VERY COLD WIND CHILL VALUES WILL BE OVER THE REGION
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 310 AM EST TUESDAY...NO BIG WX SYSTEMS TO AFFECT THE NORTH
COUNTRY THRU THE EXTENDED PERIOD. MDLS BRING STAGNANT UPPER LOW
OVER THE CANADIAN MARITIMES THURSDAY NIGHT ON INTO FRIDAY...BACK WEST
ACROSS THE GREAT LKS REGION THRU THE WEEKEND...THEN BACK EAST
AGAIN FOR NEXT MONDAY AND TUESDAY. THIS PATTERN IS A BIT SLOWER IN
ECMWF VERSUS GFS...BUT GENERAL TREND THE SAME. WK SFC RIDGE DOES
TRY TO BUILD OVER THE AREA DURING THIS TIMEFRAME...BUT CWA WILL
SEE SL CHANCE FOR -SW AS UPPER LOW RETROGRADES TO THE GREAT LKS.
BULK OF PRECIP TO REMAIN ALONG THE OUTER TRACK OF THE
LOW(PINWHEELING AROUND IT)...WITH THE NORTHEAST REGION ON THE
DRIER SIDE. CD AIRMASS WILL WRAP AROUND CIRCULATION FOR FIRST HALF
OF EXTENDED...WHICH WILL TREND TEMPS NEARLY 10 DEGREES BLW NORMAL.
BY THE LATTER HALF...W/ UPPER LOW OVER THE GREAT LKS...SOME WAA
WILL WORK INTO AREA THAT LIFT OUT SOME HIR TEMPS...BUT WILL BE
LIMITED BY CLD COVER.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THROUGH 06Z WEDNESDAY...COND WILL VARY THRU 11Z FROM VFR DOWN TO
IFR AT TIMES DUE TO LOW PRESSURE SYSTEM MVG ACROSS THE AREA.
CEILINGS DOWN TO OVC010 OR LESS ARE POSSIBLE ALONG WITH VSBY
REDUCTION DOWN AS LOW AS 1-3SM...DUE TO RAIN/SNOW SHOWERS AND FG.
AFT 11Z LL CLD COVER REMAIN ON BACKSIDE OF EXITING SYSTEM...WITH
MVFR/IFR COND. WINDS LGT/VAR...BECM WNW BY 18Z-21Z THIS AFTNOON
5-10KTS.
OUTLOOK...06Z WEDNESDAY THROUGH FRIDAY... MAINLY VFR CONDITIONS
WITH POTENTIAL FOR SOME MTN -SW AND OCCASIONAL MVFR (SLK/MPV) WEDS
THRU FRI.
&&
.EQUIPMENT...
THE ASOS TEMPERATURE SENSOR AT SAINT JOHNSBURY VERMONT (1V4) HAS BEEN
RUNNING A BIT TOO WARM LATELY. IT GAVE A HIGH TEMPERATURE OF 43
DEGREES TODAY. OUR ELECTRONICS TECHNICIANS WILL VISIT THE SITE ON TUESDAY
TO DO MAINTENANCE WORK ON THIS SENSOR. SO...PLEASE USE THIS DATA
WITH CAUTION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...AMF/LAHIFF
SHORT TERM...WGH
LONG TERM...JN
AVIATION...JN/SLW
EQUIPMENT...BTV
