National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 121935
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
235 PM EST THU DEC 12 2013

.SYNOPSIS...
A COLD FRONT HAS PUSHED SOUTH OF THE AREA AND WILL BE FOLLOWED BY
MUCH COLDER TEMPERATURES. HIGHS EACH DAY THROUGH SATURDAY WILL BE
GENERALLY IN THE TEENS. A REINFORCING COLD FRONT AND ASSOCIATED
UPPER LEVEL DISTURBANCE WILL BRING SNOW SHOWERS TO THE AREA LATER
TODAY INTO FRIDAY MORNING. SEVERAL INCHES OF SNOW ARE EXPECTED IN
THE NORTHERN ADIRONDACKS AND OVER THE NORTHERN GREEN MOUNTAINS. A
QUICK MOVING LOW PRESSURE SYSTEM PASSING SOUTH OF NEW ENGLAND
WILL BRING ADDITIONAL LIGHT SNOW SATURDAY NIGHT INTO SUNDAY.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1222 PM EST THURSDAY...NO SIGNIFICANT CHANGES FOR 1230 UPDATE.
ADJUSTED FORECAST TO MATCH CURRENT CONDITIONS AND SATELLITE
TRENDS...FORECAST FOR THIS AFTERNOON REMAINS UNCHANGED. PREVIOUS
DISCUSSION FOLLOWS.

WEAK SURFACE RIDGE BUILDING ACROSS THE NORTH COUNTRY THIS MORNING.
SKIES HAVE CLEARED ACROSS NORTHERN NEW YORK...WHILE SOME CLOUDS
LINGER ACROSS PORTIONS OF VERMONT. EXPECT THESE CLOUDS TO EXIT OR
DISSIPATE BY MID MORNING. AS RIDGE AXIS SLIDES TO OUR EAST THIS
AFTERNOON...WINDS WILL SHIFT INTO THE SOUTH AND SOUTHWEST...AND
WE WILL SEE CLOUDS QUICKLY RETURN TO NORTHERN NEW YORK ALONG WITH
INCREASING CHANCES FOR SNOW SHOWERS. LAKE EFFECT SNOWBAND OFF
LAKE ONTARIO WILL LIFT NORTH INTO SOUTHEASTERN PORTION OF SAINT
LAWRENCE COUNTY...WHERE A LAKE EFFECT SNOW ADVISORY HAS BEEN
ISSUED FOR THIS AFTERNOON THROUGH TONIGHT. ANY ACCUMULATION BY
LATER THIS AFTERNOON SHOULD BE LIMITED TO AN INCH OR TWO...WITH
MORE TO COME TONIGHT. 850 MB TEMPS THIS AFTERNOON WILL BE AROUND
-20C...ALLOWING FOR MAX TEMPS ONLY IN THE TEENS.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 454 AM EST THURSDAY...CHANCES FOR SNOW SHOWERS INCREASE
TONIGHT INTO FRIDAY MORNING AS YET ANOTHER COLD FRONT DROPS SOUTH
ACROSS THE AREA. WEST-SOUTHWEST FLOW IN ADVANCE OF THE FRONT
SHOULD ALLOW FOR SUFFICIENT MOISTURE FROM THE GREAT LAKES FOR
SCATTERED TO NUMEROUS SNOW SHOWERS...WHICH WILL BE MOST PREVALENT
OVER THE ADIRONDACKS AND HIGHER TERRAIN OF NORTHERN VERMONT. IN
ADDITION...WITH SURFACE TO 850 MB WINDS FROM THE WEST-SOUTHWEST
TONIGHT IN ADVANCE OF THE FRONT...CONDITIONS FAVORABLE FOR LAKE
ONTARIO SNOWBANDS TO IMPACT SOUTHERN ST. LAWRENCE
COUNTY...EXTENDING AT TIMES INTO SOUTHERN FRANKLIN AND ESSEX
COUNTIES AS WELL. HIGHEST TOTAL ACCUMULATION EXPECTED IN
SOUTHEAST ST LAWRENCE COUNTY WHERE 6 INCH ACCUMULATIONS POSSIBLE.
A BIT LESS JUST OUTSIDE OF THE ADVISORY AREA. ELSEWHERE...SOME
SNOW ACCUMULATIONS MAY ALSO BE EXPECTED ACROSS NORTHERN
VERMONT...ESPECIALLY THE HIGHER TERRAIN WHERE ANYWHERE FROM 1 TO
4 INCHES MAY ACCUMULATE...WITH SOME LOCALLY HEAVY SNOW SHOWERS OR
PERHAPS A SQUALL POSSIBLE IN ADVANCE OF THE FRONT.

SNOW SHOWER ACTIVITY WILL TAPER OFF FROM NORTH TO SOUTH DURING
THE DAY ON FRIDAY AS FRONT DEPRESSES SOUTH OF THE AREA. ALSO
EXPECT SOME CLEARING DURING THE AFTERNOON AS DRIER AIR ASSOCIATED
WITH HIGH PRESSURE TO THE NORTH BUILDS SOUTH INTO THE REGION. 850
MB TEMPS ON FRIDAY FALL FROM AROUND -18C IN THE MORNING TO -22C
BY DAYS END...MAKING FOR A TRICKY TEMP FORECAST. TEMPS WILL BE IN
THE TEENS FOR MUCH OF TONIGHT...WITH SOME SINGLE DIGITS OVER THE
HIGHER TERRAIN OF NORTHERN ZONES. WITH LOW LEVEL COLD AIR
ADVECTION DURING FRIDAY...EXPECT MORNING HIGHS TO RANGE FROM LOW
TEENS NORTH TO LOWER 20S SOUTH...WITH FALLING TEMPS THEREAFTER ON
NORTHERLY BREEZES.

SURFACE RIDGE BUILDS INTO THE NORTH COUNTRY FRIDAY
NIGHT...RESULTING IN MAINLY CLEAR SKIES AND VERY COLD
TEMPERATURES...WITH MANY LOCATIONS DROPPING BELOW ZERO. NORMALLY
COLDER PORTIONS OF THE ADIRONDACKS AND NORTHEAST KINGDOM MAY SEE
LOWS OF 15 TO 20 BELOW. IT WILL REMAIN UNSEASONABLY COLD ON
SATURDAY AS THE HIGH MAKES ITS WAY EAST INTO MAINE AND THE
MARITIMES. EXPECT HIGHS MAINLY FROM 10 TO 15 DEGREES. WE WILL
ALSO SEE INCREASING CLOUDS WITH SOME LIGHT SNOW DEVELOPING FROM
SOUTHWEST TO NORTHEAST ACROSS THE REGION DURING THE AFTERNOON.
THIS DUE TO A PAIR OF DEVELOPING LOW PRESSURE SYSTEMS...ONE OVER
THE OHIO VALLEY AND THE OTHER NEAR THE MID ATLANTIC COAST.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 300 PM EST THURSDAY...LITTLE CHANGE WITH REGARDS TO
DEPARTING STORM ON SUNDAY AND OVERALL LARGE SCALE SYNOPTIC PATTERN
FOR EARLY NEXT WEEK. GFS/ECMWF AND ENSEMBLE MEMBERS CONT TO
SUPPORT MEAN TROF ACRS THE NE CONUS WITH POTENTIAL FOR SOME
RIDGING TWD THE MID OF NEXT WEEK. MODELS HAVE TRENDED SLIGHTLY
CLOSER TO THE COAST FOR LOW PRES ON SUNDAY WITH TRACK FROM EASTERN
LONG ISLAND TO JUST INSIDE THE BENCHMARK BY 18Z SUNDAY. THIS WL
RESULT IN A WIDESPREAD ACCUMULATING SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...WITH MOST OF THE SNOW ENDING BY 18Z SUNDAY. SYSTEM CONTS
TO BE VERY PROGRESSIVE IN THE FAST 700 TO 500MB SW FLOW
ALOFT...WITH MID LVL DRY SLOT IMPACTING OUR CWA BY EARLY SUNDAY
AFTN...RESULTING IN A OVERALL DECREASE IN SNOWFALL. THINKING
STORM TOTAL QPF WL RANGE BTWN 0.20 AND 0.50" ACRS OUR CWA WITH
HIGHEST VALUES ACRS THE SE UPSLOPE REGIONS. GIVEN THE VERY COLD
THERMAL PROFILES EXPECTING VERY HIGH FLUFF FACTOR WITH RATIOS BTWN
20 AND 30 TO 1. THIS WL RESULT IN A GENERAL ADVISORY TYPE EVENT
WITH SLIGHTLY HIGHER AMOUNTS ACRS SE VT ZNS. SOUNDINGS SHOW GOOD
RH IN FAVORABLE SNOW GROWTH REGION...ALONG WITH SOME 850 TO 700MB
OMEGA...WHICH WL HELP IN SNOW FLAKE PRODUCTION. OTHERWISE...DEEP
LAYER MOISTURE QUICKLY SHIFTS NE OF FA BY 00Z MONDAY WITH AREAS OF
FLURRIES EXPECTED. TEMPS WL STRUGGLE IN THE TEENS TO LOWER 20S ON
SUNDAY.

BOTH ECMWF/GFS SHOW POTENT NORTHERN STREAM ENERGY AND CLOSED 5H/7H
CIRCULATION PASSING TO OUR NORTH SUNDAY NIGHT INTO MONDAY...BUT
MOISTURE IS LIMITED. THE DYNAMICS COMBINED WITH A WEAK SFC TROF WL
PROBABLY PRODUCE ADDITIONAL SNOW SHOWER ACTIVITY. PROGGED 85H
TEMPS DROP ONCE AGAIN TO NEAR -20C BY 12Z MONDAY...SUPPORTING MUCH
BLW NORMAL TEMPS. THE COMBINATION OF DEPARTING LOW PRES AND
BUILDING HIGH PRES WL RESULT IN SOME BRISK CONDITIONS ON MONDAY.
NEXT CLIPPER LIKE SYSTEM APPROACHES CWA ON TUES/WEDS WITH
ADDITIONAL MOISTURE/DYNAMICS. INITIAL SFC LOW PRES IS EXPECTED TO
PASS NORTH OF OUR CWA...BUT LATEST 12Z GEM/ECMWF SHOW SOME
SECONDARY DEVELOPMENT ACRS SNE...WHICH COULD RESULT IN ANOTHER
BRIEF PERIOD OF LIGHT SNOW. WL MENTION HIGH CHC POPS ATTM...WITH
TEMPS WARMING BACK INTO THE UPPER TEENS TO M/U 20S IN THE WARMER
VALLEYS. LOWS WL BE TRICKY THRU THE PERIOD...WITH THE COLDEST TEMPS
ON SUNDAY/MONDAY NIGHT...WITH READINGS BLW ZERO TO +5F.
-- End Changed Discussion --

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...SFC HIGH PRES OVERHEAD HAS RESULTED IN VFR
CONDITIONS WITH LIGHT AND VARIABLE WINDS TODAY. THIS WL SHIFT EAST
WITH A RETURN SOUTHWEST FLW DEVELOPING...BY LATE THIS AFTN. THIS
WL HELP ADVECT LLVL LAKE EFFECT MOISTURE BACK INTO OUR CWA BY THIS
EVENING...WITH SOME SCATTERED SNOW SHOWER ACTIVITY. A PERIOD OF
IFR CONDITIONS WL BE LIKELY AT SLK BTWN 22Z-03Z THIS EVENING AND
HAVE MENTIONED A PREVAILING GROUP WITH 2SM -SN BR WITH TEMPO OF
3/4SM -SN. NEXT ARCTIC BOUNDARY APPROACHES MSS BY 07Z AND INTO THE
CPV AROUND 11Z WITH A FINE LINE OF SNOW SHOWERS AND SQUALLS. A
BRIEF 20 TO 30 MINUTE PERIOD OF IFR/LIFR CONDITIONS WL BE POSSIBLE
WITH VIS <1SM AND CIGS AROUND 1500 FEET. EXPECT GUSTY SOUTH TO
SOUTHWEST WINDS TO DEVELOP THIS EVENING...ESPECIALLY AT
SLK/MSS/PBG AND BTV...WITH SOME GUSTS TO 25 KNOTS POSSIBLE. AREAS
OF LLVL TURBULENCE WL BE POSSIBLE...GIVEN WIND FIELDS. THESE WINDS
WL SHIFT TO THE NORTHWEST BEHIND FROPA ON FRIDAY MORNING WITH SOME
LAKE CHAMPLAIN SNOW SHOWERS IMPACTING BTV BTWN 12-16Z.

OUTLOOK 18Z FRIDAY THROUGH MONDAY...
SFC HIGH PRES WITH VFR CONDITIONS 18Z FRIDAY THRU 18Z SATURDAY.
NEXT SYSTEM IMPACTS ALL OUR TAF SITES WITH WIDESPREAD IFR
CONDITIONS LATE SAT INTO SUNDAY...WITH PERIODS OF LIFR CONDITIONS
POSSIBLE IN THE HEAVIER SNOW ON SAT NIGHT. A SLOW CLRING TREND IS
EXPECTED AFT 18Z SUNDAY WITH VFR CONDITIONS DEVELOPING. WINDS WL
GENERALLY BE FROM THE NORTH ON FRIDAY INTO SATURDAY...BEFORE
SHIFTING TO THE SOUTH/SOUTHEAST WITH SOME LOCALIZED HIGHER GUSTS
POSSIBLE NEAR RUTLAND ON SATURDAY NIGHT.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ029.

&&

$$
SYNOPSIS...RJS
NEAR TERM...RJS/NEILES
SHORT TERM...RJS
LONG TERM...TABER
AVIATION...TABER