FXUS61 KBTV 150547
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1247 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 TODAY/...
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 /TONIGHT THROUGH WEDNESDAY NIGHT/...
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 THROUGH MONDAY/...
AS OF 305 PM EST MONDAY...LITTLE CHANGE FROM PREVIOUS COUPLE DAYS
FCST WITH REGARDS TO DAYS 4 THRU 7. LARGE SCALE SYNOPTIC PATTERN
WL FEATURE DEEP MID/UPPER LVL TROF ACRS EASTERN CANADA/NE CONUS
WITH MUCH BLW NORMAL TEMPS AND PRECIP EXPECTED. GIVEN...POSITION
OF CLOSED 7H/5H SYSTEM...FEEL BEST WRAP AROUND MOISTURE/DYNAMICS
WL INITIALLY BE ACRS NORTHERN MAINE INTO EASTERN CANADIAN
MARITMES. EVENTUALLY BY NEXT WEEKEND SYSTEM IS EXPECTED TO RETRO-
GRADE BACK WEST AND MAY IMPACT OUR CWA WITH SOME SNOW SHOWERS. IN
ADDITION...WE WL BE WATCHING EMBEDDED VORTS ROUNDING MID/UPPER LVL
CIRCULATION FOR POTENTIAL IMPACTS TO OUR CWA BY NEXT WEEKEND.
OTHERWISE...UPSLOPE FLW WL PREVAIL THURS THRU FRIDAY...BUT
SOUNDINGS SHOW VERY LIMITED MOISTURE...THEREFORE MAYBE A FEW MTN
FLURRIES/ISOLATED SNOW SHOWERS. VERY LIGHT ACCUMULATIONS
EXPECTED...IF AT ALL.
BIG STORY WL BE THE BITTERLY COLD TEMPS ON BRISK NW WINDS FOR
THURS INTO THE WEEKEND. NAM 2M TEMPS SUGGEST A HIGH AROUND 5F FOR
SLK AND L10S FOR BTV ON THURS. WL TREND SLIGHTLY HIGHER...BUT 2 TO
4 DEGREES BLW MOS NUMBERS. OTHERWISE...IF SKIES CLR AND WINDS BCM
LIGHT...SEVERAL LOCATIONS (SLK/NEK) COULD SEE OVERNIGHT LOWS BTWN
-10 AND -20F. HOWEVER...FEEL WINDS/LOW CLOUDS WL KEEP LOWS BTWN -5
AND -10F AT SLK/MTN LOCATIONS FOR THURS AND FRI NITES. HIGH TEMPS
WL SLOWLY WARM INTO THE 20S BY NEXT WEEKEND WITH LOWS IN THE
SINGLE DIGITS AND TEENS.
&&
.AVIATION /06Z 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...TABER
AVIATION...JN/SLW
EQUIPMENT...BTV
