Area Forecast Discussion
Issued by NWS Burlington, VT

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871
FXUS61 KBTV 092030
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
330 PM EST TUE FEB 9 2016

.SYNOPSIS...
AN EXTENDED PERIOD OF LIGHT SNOW IS EXPECTED ACROSS THE NORTH
COUNTRY LATE TONIGHT THROUGH THURSDAY NIGHT, BUT ACCUMULATIONS
WILL BE VERY LIGHT, TOTALING 3 TO 5 INCHES OVER THE 48 HOUR
PERIOD. DRIER AND MUCH COLDER CONDITIONS ARE EXPECTED FOR THE
WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 330 PM EST TUESDAY...SYNOPTIC PATTERN CHANGES VERY LITTLE
OVER THE NEXT 24 HOURS AS A BROAD UPPER TROUGH CENTERED OVER THE
EASTERN GREAT LAKES SLOWLY SHIFTS EASTWARD OVER THE MID-ATLANTIC
AND NORTHEAST STATES BY WEDNESDAY AFTERNOON. WE`RE STILL DEALING
WITH SOME LINGERING MOISTURE AND UPPER LEVEL ENERGY ASSOCIATED
WITH A WEAKER UPPER LEVEL LOW OVER THE GULF OF ST. LAWRENCE THIS
AFTERNOON WITH LIGHT SNOW BEING OBSERVED ALONG THE CANADIAN BORDER
NEAR MASSENA, BUT OVERALL TRENDS GOING INTO THE EVENING AND EARLY
OVERNIGHT HOURS WILL BE TOWARDS DRIER WEATHER WITH ABUNDANT CLOUD
COVER PERSISTING.

AS WE HEAD TOWARDS THE EARLY MORNING HOURS OF WEDNESDAY AND THE
AFOREMENTIONED UPPER TROUGH AXIS APPROACHES THE BTV CWA, THE
ASSOCIATED WEAK SURFACE LOW CURRENTLY IN THE VICINITY OF TORONTO
WILL SHIFT INTO THE ST. LAWRENCE VALLEY AND EVENTUALLY ACROSS THE
NORTH COUNTRY BY THE AFTERNOON. WEAK WARM AIR ADVECTION PROCESSES
AND LAKE ENHANCED MOISTURE WILL DEVELOP FAIRLY WIDESPREAD LIGHT
SNOW ACROSS THE REGION BUT BASED ON THE LIMITED MOISTURE IN THE
FAVORABLE SNOW GROWTH ZONE THINK THE DENDRITES WILL BE FAIRLY
SMALL AND TOUGH TO ACCUMULATE MUCH MORE THAN 1-2".

IN REGARDS TO TEMPS, WITH ABUNDANT CLOUD COVER IN PLACE FOR
TONIGHT AND LITTLE OVERALL AIRMASS CHANGE FROM LAST NIGHT, MIN
TEMPS SHOULD BE A FEW DEGREES WARMER THAN THIS MORNING, GENERALLY
IN THE UPPER TEENS TO MID 20S. TEMPS WARM TOWARDS SEASONAL NORMALS
TOMORROW ASSOCIATED WITH THE ABOVE MENTIONED WEAK WARM AIR
ADVECTION, AND SHOULD TOP OUT IN THE MID 20S TO AROUND 30.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 235 PM EST TUESDAY...SYNOPTIC SCALE FEATURES SHOW
DEVELOPING DEEP MID/UPPER LEVEL TROF ACROSS THE GREAT LAKES INTO
THE NE CONUS. HAVE NOTED AN INTERESTING INVERTED SURFACE TROF LIKE
FEATURE IN THE SEA LEVEL PRES FIELDS ACROSS NORTHERN NY INTO
CENTRAL VT ON WED NIGHT. WHILE ALOFT A WEAK 5H VORT WILL BE
LIFTING FROM SOUTHWEST TO NORTHEAST ACROSS OUR REGION WITH SOME
ENHANCED 850 TO 500MB MOISTURE. THIS LOW LEVEL CONVERGENCE
COMBINED WITH SOME NW UPSLOPE FLOW ACROSS THE NORTHERN MTNS WILL
PRODUCE A PERIOD OF LIGHT ACCUMULATING SNOWFALL. HOWEVER...PW
VALUES ARE ONLY BETWEEN 0.15 AND 0.22...SO LOOKING AT A GENERAL
DUSTING TO 3 INCHES POSSIBLE. VERY SIMILAR TO OUR EVENT MONDAY
NIGHT INTO TUESDAY MORNING. HAVE NOTED SLIGHTLY BETTER OMEGA
FIELDS...ALONG WITH FAVORABLE MOISTURE/LIFT IN THE -10C TO -18C
SNOW GROWTH REGION...HELPING WITH FLAKE PRODUCTION. TEMPS WILL BE
HIGHLY DEPEND UPON CLOUDS...SO THINKING ABOVE GUIDANCE WITH VALUES
MAINLY IN THE TEENS TO NEAR 20F WEDS NIGHT AND FALLING ON THURSDAY
UNDER MODERATE LOW LEVEL COLD AIR ADVECTION. HAVE NOTED 850MB
TEMPS AT 12Z THURSDAY ARE BETWEEN -12C AND -14C...BUT FALL BETWEEN
-20C AND -24C BY 00Z FRIDAY. TEMPS WILL FALL BELOW ZERO MOUNTAIN
SUMMITS TO MID/UPPER TEENS VALLEYS ON THURSDAY. THE COMBINATION OF
INCREASED 925MB TO 850MB WINDS OF 20 TO 35 KNOTS AND SOME LEFTOVER
850 TO 700MB MOISTURE WILL CONTINUE TO PRODUCE UPSLOPE SNOW
SHOWERS ON THURSDAY. WILL MENTION LIKELY POPS MOUNTAINS TO CHC IN
THE VALLEYS WITH ANOTHER COUPLE OF INCHES POSSIBLE. BY THURSDAY
NIGHT BETTER MOISTURE SHIFTS TO OUR EAST...AS DRY NORTHWEST FLOW
PREVAILS. PROGGED 850MB TEMPS BOTTOM OUT BETWEEN -20C AND
-24C...BUT AMOUNT OF CLEARING AND EXPECTED WINDS WILL MAKE
OVERNIGHT LOW TEMPS CHALLENGING. WILL MENTION VALUES RANGING FROM
-5F SLK/NORTHEAST KINGDOM TO 10F WARMER VALLEYS.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 235 PM EST TUESDAY...COLDEST AIRMASS OF THE SEASON
EXPECTED LATE FRIDAY INTO THE WEEKEND...VERY SIMILAR TO SEVERAL COLD
OUTBREAKS DURING FEB OF 2015. LARGE SCALE PICTURE SHOWS POLAR VORTEX
MOVING DIRECTLY OVERHEAD ON FRIDAY NIGHT INTO SATURDAY WITH PROGGED
1000 TO 500MB THICKNESS VALUES DOWN TO 480 DAM AND PROGGED 850MB
TEMPS BETWEEN -30C AND -34C. THIS ARCTIC BOUNDARY MAYBE ACCOMPANIED
BY A BRIEF 20 TO 30 MINUTE PERIOD OF SNOW SHOWERS AND POSSIBLE SNOW
SQUALLS. GFS SHOWS FAVORABLE SHORT WAVE ENERGY AND GOOD LOW LEVEL
CONVERGENCE WITH BOUNDARY ALONG WITH SOME ENHANCED MID LEVEL
MOISTURE. WILL MENTION CHC POPS...BUT THIS FEATURE WILL NEED TO BE
WATCHED.

THE GFS ENSEMBLE MEAN SHOWS VALUES AROUND -32C...WHICH IS 3 TO 4 STD
BELOW NORMAL ON SATURDAY WITH PROGGED 925MB TEMPS BETWEEN -28C AND
-30C. ALL THIS SUPPORTS HIGHS BETWEEN -5F AND -10F FOR SLK/NORTHEAST
KINGDOM WITH 0 TO +5F IN THE WARMER VALLEYS WITH BRISK NORTHWEST
WINDS OF 5 TO 15 MPH...CREATING BITTERLY COLD WIND CHILL VALUES.
WIND CHILL ADVISORIES AND WARNINGS WILL BE NEEDED FROM LATE FRIDAY
NIGHT INTO SUNDAY...BASED ON CURRENT FORECAST. BY EARLY SUNDAY
MORNING 1045MB ARCTIC HIGH PRES IS LOCATED OVER THE CENTRAL GREAT
LAKES WITH STILL SOME NORTHWEST GRADIENT OVER OUR FA. THIS MAY KEEP
TEMPS FROM COMPLETING BOTTOMING OUT...BUT STILL EXPECTING LOWS FROM -
25F TO -5F...WITH WARMEST VALUES NEAR THE IMMEDIATE LAKE CHAMPLAIN
SHORELINE. ALSO...WITH NORTHWEST WINDS SOME LAKE ENHANCED CLOUDS MAY
KEEP TEMPS UP IN THE BTV/SHELBURNE AREAS. HIGHS WILL SLOWLY REBOUND
ON SUNDAY WITH DEVELOPING LOW LEVEL WARM AIR ADVECTION...ESPECIALLY
AS PROGGED 850MB TEMPS WARM TO NEAR -18C BY 00Z MONDAY. AFTER A VERY
COLD START...EXPECT HIGHS MAINLY IN THE SINGLE DIGITS TO LOWER/MID
TEENS. TEMPERATURES WILL CONTINUE TO WARM WITH MAINLY DRY
CONDITIONS FOR EARLY NEXT WEEK. NEXT CHANCE FOR RAIN OR SNOW
ARRIVES BY TUESDAY INTO WEDNESDAY WITH TEMPERATURES MAINLY IN THE
30S.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...VARIABLE FLIGHT CONDITIONS ACROSS THE AREA
CURRENTLY WITH SOME IFR/MVFR VSBY DUE TO LIGHT SNOW WILL GENERALLY
TREND TOWARDS A MIX OF MVFR/VFR CIGS OVER THE NEXT FEW HOURS WITH
VSBY RETURNING TO VFR AS SNOW DISSIPATES. FOR THE OVERNIGHT HOURS,
MVFR/VFR CIGS WILL PERSIST WITH VFR VSBY THROUGH 06Z. AFTER 06Z
SNOW RETURNS BEGINNING AT KSLK/KMSS WITH VSBY LOWERING BACK TO
IFR, THEN PROGRESSING EASTWARD AFTER 12Z. LIGHT SNOW WITH IFR VSBY
AND MVFR CIGS IS LIKELY FROM 12-18Z WEDNESDAY AREA-WIDE. WINDS
GENERALLY LIGHT THROUGH THE PERIOD, EXCEPT NORTHEASTERLY AT
8-12KTS AT KMSS THROUGH 00Z.

OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WED - 12Z SAT...MIX OF MVFR/VFR CIGS WITH PERIODS OF MVFR/IFR VSBY
IN LIGHT SNOW. SNOW SQUALLS POSSIBLE 18Z FRIDAY TO 06Z SATURDAY.

12Z SAT - 00Z MON...GENERALLY VFR UNDER HIGH PRESSURE. BRIEF MVFR
POSSIBLE.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...TABER
LONG TERM...TABER
AVIATION...LAHIFF



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