Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 292359
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
659 PM EST THU JAN 29 2015

.SYNOPSIS...
A WEAK CLIPPER LIKE SYSTEM WILL PRODUCE A WIDESPREAD LIGHT SNOW
TONIGHT INTO FRIDAY...FOLLOWED BY UPSLOPE SNOW SHOWERS AND
BITTERLY COLD TEMPERATURES FRIDAY NIGHT. HIGH PRESSURE WILL BUILD
IN FOR THE WEEKEND WITH TEMPERATURES MUCH BELOW NORMAL.
TEMPERATURES OF 10 TO 15 DEGREES BELOW NORMAL WILL PERSIST INTO
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
AS OF 629 PM EST THURSDAY...
HEADLINES: WINTER WEATHER ADVISORIES CONTINUE TO BE IN AFFECT FOR
ENTIRE FORECAST AREA FOR TONIGHT INTO FRIDAY EVENING.

WV/IR SATELLITE SHOW THE CLIPPER DEVELOPING QUITE NICELY OVER THE
GREAT LAKES AND BEGINNING TO WRAP UP. THE MID TO UPPER LEVEL
MOISTURE IS QUICKLY INCREASING HOWEVER THAT HASN`T YET REACHED
THE GROUND OVER NORTHERN NEW YORK. CURRENT COMPOSITE RADAR AND
GROUND TRUTH PRESENT TWO DRASTICALLY DIFFERENT SOLUTIONS RIGHT NOW
AS THE SURFACE OBS ARE SHOWING DEWPOINT DEPRESSIONS OF 21 DEGREES
AT OGDENSBURG. AT THAT POINT THE LOW LEVEL MOISTURE JUST HASN`T
REACHED THE GROUND AND THE METAR IS REPORTED CLEAR BELOW 12,000
FEET. UNTIL THE LOW LEVELS BECOME SATURATED EXPECT THE PRECIP TO
ESSENTIALLY BE VIRGA. ADDITIONALLY ACROSS MUCH OF THE ST LAWRENCE
VALLEY SURFACE TEMPS ARE IN THE MID TO UPPER 30`S SO ANY PRECIP
THAT IS FALLING WILL MOST LIKELY BE A WINTRY MIX OF SNOW OR RAIN
FOR THE NEXT HOUR OR TWO. EXPECT OVER THE NEXT 2-3 HOURS THE LOW
LEVELS SHOULD SATURATE AND BECOME SNOW SHOWERS FOR MOST OF THE
OVERNIGHT HOURS AS THE CLIPPER MOVES EASTWARD. ONLY REAL CHANGES
TO THE FORECAST WERE TO UP THE TEMPS OVER THE ST LAWRENCE VALLEY
MATCHING OBS AND THEN TREND BACK HOW QUICKLY THE PRECIP MOVES
ACROSS THE FORECAST REGION DUE TO THE DRY AIR IN THE VERY LOW
LEVELS. THE REST OF THE FORECAST LOOKS ON TRACK TO DROP INTO THE
UPPER TEENS TO NEAR 20 ACROSS THE REGION WITH LIGHT TO MODERATE
SNOWFALL OVERNIGHT.

PREVIOUS DISCUSSION...CLOUDS THICKENING UP ACROSS FORECAST AREA
FROM WEST TO EAST WITH APPROACH OF SHORTWAVE AND ASSOCIATED
CLIPPER SYSTEM FROM THE GREAT LAKES. RADAR SHOWING SOME
PRECIPITATION...MAINLY ALOFT...ACROSS MUCH OF NORTHERN NEW YORK.
AS LOW LEVELS GRADUALLY BECOME MORE SATURATED OVER NEXT SEVERAL
HOURS...EXPECT SNOW TO DEVELOP...AND THEN SPREAD EAST ACROSS
VERMONT THROUGH FIRST HALF OF TONIGHT. A STRONG SOUTH-
SOUTHWESTERLY LOW LEVEL JET WILL BRING SOME GUSTY WINDS TO THE
REGION... ESPECIALLY OVER THE BROAD VALLEYS AND OVER THE HIGHER
TERRAIN. THIS WILL RESULT IN SOME BLOWING SNOW AND FURTHER REDUCE
VISIBILITIES. THIS JET WILL ALSO CAUSE SHADOWING AFFECTS IN THE
CHAMPLAIN VALLEY AND NORTHEASTERN SLOPES. BY MORNING...EXPECT 1 TO
3 INCHES OF SNOW ACROSS MOST OF THE REGION. TEMP TONIGHT NOT
FALLING ALL THAT MUCH...LOOK FOR LOWS IN THE UPPER TEENS TO MID
20S.

&&

.SHORT TERM /7 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 330 PM EST THURSDAY...THE CENTER OF THE CLIPPER TRAVERSES
NEAR THE INTERNATIONAL BORDER EARLY FRIDAY MORNING...THEN
REDEVELOPS OFF THE SOUTHERN NEW ENGLAND COAST IN THE AFTERNOON AS
THE ASSOCIATED MID LEVEL TROUGH DIGS AND TAKES ON A NEGATIVE TILT.
THIS WILL RESULT IN THE SURFACE LOW SLOWING ITS EASTWARD
PROGRESSION INTO GULF OF MAINE. THE RESULT WILL BE A TRANSITION OF
SYNOPTIC SNOW TO UPSLOPE SNOW OR SNOW SHOWERS ACROSS
VERMONT...WHICH WILL CONTINUE INTO FRIDAY NIGHT. THE SNOW WILL
TAPER OFF EARLIER ACROSS NORTHERN NEW YORK.

BEHIND THE SURFACE LOW AND WITH PASSAGE OF COLD FRONT...SOUTHERLY
WINDS WILL SHIFT INTO THE NORTH. THIS COMBINED WITH LINGERING
MOISTURE WILL PRODUCE UPSLOPE SNOW SHOWERS WITH FROUDE NUMBERS
SHOWING BLOCKED FLOW. WHEN ALL IS SAID AND DONE...EXPECT 3-7 INCHES
OF SNOWFALL FOR THE ST LAWRENCE VALLEY...STRETCHING ACROSS THE
NORTHERN TIER OF OUR ZONES ACROSS THE CENTRAL CHAMPLAIN VALLEY AND
ALL OF NORTHERN VERMONT. DUE TO SHADOWING...ESSEX COUNTY NY AND
THE SOUTHERN CHAMPLAIN VALLEY AND SOUTH CENTRAL VT WILL RECEIVE
JUST A BIT LESS...WITH 2-5 INCHES EXPECTED. SOME LOCALLY HIGHER
AMOUNTS ARE ALSO POSSIBLE...ESPECIALLY OVER THE WESTERN SLOPES OF
THE NORTHERN GREEN MOUNTAINS.

THE NORTHWEST FLOW WILL USHER IN COLDER AIR WITH NON DIURNAL
TEMPERATURE TREND EXPECTED FRIDAY. DRIER AIR WILL ALSO BE
FILTERING IN FRIDAY ALLOWING SKIES TO CLEAR ACROSS NORTHERN NEW
YORK. PRESSURE GRADIENT WILL INCREASE LATE FRIDAY INTO FRIDAY
NIGHT WITH COASTAL LOW DEEPENING AND HIGH PRESSURE BUILDING TO
OUR WEST. THESE FEATURES WILL RESULT IN VERY COLD TEMPERATURES
FRIDAY NIGHT INTO SATURDAY. 925MB TEMPS WILL FALL TO BETWEEN -10C
AND -20C FRIDAY NIGHT...WHICH WILL BE REFLECTED AT THE SURFACE IN
TERMS OF SATURDAY MORNING LOWS RANGING FROM A BIT ABOVE ZERO
SOUTHERN AND EASTERN VERMONT TO THE TEENS BELOW ZERO ACROSS
MUCH OF NORTHERN NEW YORK. COMBINATION OF TEMPS AND WIND WILL
LIKELY RESULT IN SOME WIND CHILL ISSUES...WITH POSSIBILITY OF AT
LEAST ADVISORIES FOR LATE FRIDAY NIGHT INTO SATURDAY.

MAX TEMPS SATURDAY UNDER PARTLY TO MOSTLY SUNNY SKIES WILL BE
ONLY IN THE SINGLE NUMBERS TO LOWER TEENS...ALTHOUGH WINDS WILL
ABATE DURING THE AFTERNOON. ANOTHER FRONT WILL DROP INTO THE AREA
FROM THE NORTHWEST SATURDAY NIGHT. NOT MUCH IN WAY OF AVAILABLE
MOISTURE...BUT ENOUGH FOR AT LEAST THE MENTION OF A CHANCE OF SNOW
SHOWERS...ESPECIALLY OVER THE NORTHERN MOUNTAINS.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 254 PM EST THURSDAY...VERY LITTLE CHANGE TO PREVIOUS
FORECAST THINKING FOR THE EXTENDED PERIOD AS TODAYS 12Z MODEL
SUITE REMAINS IN GOOD AGREEMENT KEEPING ANY MAJOR SYSTEMS AWAY
FROM THE NORTH COUNTRY.

LINGERING SNOW SHOWERS REMAIN POSSIBLE MAINLY ACROSS THE HIGHER
TERRAIN SUNDAY AS AN ARCTIC FRONT PUSHES INTO THE REGION. TRICKY MAX
TEMPS FORECAST AT THIS TIME BASED ON FRONTAL PASSAGE TIMING, BUT
BASED ON FALLING 925-850MB TEMPS THROUGH THE DAY THINK HIGHS WILL BE
EARLY IN THE MORNING AND SLOWLY FALL OFF THROUGH THE DAY. MEANWHILE,
STILL MONITORING THE POTENTIAL DEVELOPMENT OF SURFACE LOW PRESSURE
OVER THE TENNESSEE RIVER VALLEY LATE SUNDAY INTO SUNDAY NIGHT WHICH
WILL INTENSIFY OFF THE EASTERN SEABOARD MONDAY. LATEST TRENDS OF THE
12Z ECMWF AND GFS CONTINUE THE IDEA THAT THIS SOUTH STREAM ENERGY
DOESN`T PHASE WITH THE NORTHERN STREAM TROUGH DIGGING THROUGH THE
GREAT LAKES WHICH NEVER BECOMES NEGATIVELY TILTED AND REMAINS AN
OPEN WAVE AT 500MB. THIS RESULTS IN A MORE WESTERLY TRACK OF THE
SURFACE LOW INITIALLY, CAUSING IT TO PASS WELL TO OUR SOUTH AND EAST
OF THE BENCHMARK. SO BASICALLY A NON-EVENT FOR US, SIGH.

BEYOND MONDAY PATTERN TURNS COLD AND DRY FOR MONDAY NIGHT THROUGH
TUESDAY NIGHT AS A STRONG 1030MB HIGH SETTLES OVER THE MID-ATLANTIC
AND NORTHEAST. TEMPS WILL STRUGGLE TO WARM INTO THE SINGLE DIGITS
TUESDAY AND FALL BELOW ZERO AREA-WIDE BOTH NIGHTS. THIS WILL BE A
BRIEF BLAST OF CLOD THOUGH AS THE HIGH SHIFTS EAST OFF THE COAST FOR
WEDNESDAY WITH SOUTHERLY RETURN FLOW WARMING TEMPS BACK INTO THE
TEENS AND 20S. NEXT CHANCE FOR SNOW COMES WITH A CLIPPER SYSTEM
SHIFTING THROUGH THE AREA WEDNESDAY AND WEDNESDAY NIGHT.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THROUGH 00Z SATURDAY...PERIODS OF LIGHT SNOW WILL AFFECT TAF SITES
THROUGH FRIDAY BRINGING A VARIETY OF FLIGHT CATEGORIES...BUT
A PREDOMINANT TREND TO MVFR/IFR. LIGHT SNOW SHOWERS WILL
OVERSPREAD THE REGION BETWEEN 00Z AND 04Z...WITH GREATEST COVERAGE
AND INTENSITY GENERALLY 06Z TO 12Z. THUS WILL SEE A DOWN TREND IN
VISIBILITIES AND CEILINGS TO MAINLY MVFR/IFR. GUSTY SOUTH WINDS
UP TO 25 KNOTS WILL GRADUALLY DECREASE TOWARDS MORNING. WINDS WILL
TURN TO THE NORTHWEST FROM 5 TO 15 KNOTS WITH SOME HIGHER GUSTS ON
FRIDAY...LEADING TO MORE TERRAIN DRIVEN SNOW SHOWERS CONTINUING
THROUGH THE DAY...ESPECIALLY BTV/MPV/RUT/SLK.

OUTLOOK 00Z SATURDAY THROUGH TUESDAY...

00Z SATURDAY-12Z SATURDAY...SLOW IMPROVEMENT AS SNOW SHOWERS END.
GUSTY NORTHWEST WINDS WILL RESULT IN AREAS OF BLOWING SNOW.

12Z SATURDAY-12Z MONDAY...VFR.

12Z MONDAY-00Z WEDNESDAY...MAINLY VFR AS SYSTEM SLIDES SOUTH OF
REGION.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER WEATHER ADVISORY UNTIL 1 AM EST SATURDAY FOR VTZ001>012-
     016>019.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR NYZ026>031-
     034-035-087.

&&

$$
SYNOPSIS...RJS
NEAR TERM...RJS
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...MUCCILLI/NASH



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