Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 271156
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
656 AM EST TUE JAN 27 2015

.SYNOPSIS...
STRONG COASTAL LOW PRESSURE WILL SPREAD WIDESPREAD LIGHT TO
MODERATE SNOWS ACROSS THE EASTERN HALF OF THE FORECAST AREA TODAY
INTO EARLY THIS EVENING. HIGH PRESSURE RETURNS FOR LATER TONIGHT
THROUGH EARLY THURSDAY WITH SEASONABLY COLD AND MAINLY DRY
WEATHER. MORE LIGHT SNOWS ARE EXPECTED BY THURSDAY NIGHT INTO
FRIDAY AS LOW PRESSURE TRACKS EAST FROM THE GREAT LAKES STATES.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 635 AM EST TUESDAY...FORECAST GENERALLY REMAINS ON TRACK
AND ONLY CHANGES AT 630 AM WERE TO MATCH CURRENT T/TD TRENDS
ACROSS THE AREA. I AM GROWING A BIT CONCERNED ON OUR SNOWFALL
TOTALS ON THE NORTHWESTERN EDGE OF THE PCPN SHIELD WITH LATEST
MODEL TRENDS CONTINUING TO SUGGEST DRY LOWER LEVELS WILL TEND TO
OVERCOME MID LEVEL DYNAMICS FOSTERING A GENERAL EROSION OF THE
WESTERN EDGE OF THE PCPN SHIELD ACROSS OUR AREA.
ADDITIONALLY...LOW LEVEL MOISTURE TRANSPORT TO THE NORTHWEST IS
APPEARING TO BE BLOCKED BY THE INTENSE MESOSCALE BAND ACROSS EC/SE
NEW ENGLAND. THIS IS NOT AN UNCOMMON OCCURRENCE...BUT DIFFICULT TO
PREDICT UNTIL IT DEVELOPS. WE`LL HAVE TO SEE HOW THINGS EVOLVE
OVER THE NEXT 3-5 HOURS BUT NO CHANGES AT THIS POINT. PRIOR
DISCUSSION FOLLOWS. HAVE A GREAT DAY.

PRIOR DISCUSSION FROM 321 AM EST TUESDAY...
INTENSE STORM CONTINUES TO DEVELOP OFF THE SOUTHEASTERN NEW
ENGLAND COAST NEAR NANTUCKET EARLY THIS MORNING WITH IMPRESSIVE
3-HOURLY PRESSURE FALLS NEAR 8 MB JUST NORTH OF THE 40N/-70W
BENCHMARK PER MOST RECENT MSAS ANALYSIS. A CLASSIC MILLER-B
EVOLUTION WITH INTENSE FRONTOGENETICAL BANDING FEATURES PIVOTING
SLOWLY NORTH AND WEST ACROSS ERN MA/CT/LI. THE DEVIL IS IN THE
DETAILS HOWEVER...ESPECIALLY IN REGARD TO TOTAL QPF/SNOWFALL
ACROSS OUR AREA. LATEST CAM OUTPUT INCLUDING THE RAP AND HRRR ALL
COMING ON BOARD WITH FAIRLY REALISTIC SOLUTIONS SHOWING WESTERN
EDGE OF STEADIER SNOWS WILL SLOWLY PIVOT NORTH AND WEST INTO VT
THROUGH THE COURSE OF THE MORNING/EARLY AFTERNOON WITH A RATHER
SHARP CUTOFF IN PCPN THE FURTHER NORTH AND WEST ONE PROGRESSES.
MOST PROBLEMATIC IS THE VERY COLD AND DRY ARCTIC AIRMASS IN PLACE
ACROSS OUR AREA. INDEED...LOW TO MID LEVEL DEWPOINTS REMAIN QUITE
LOW THIS MORNING AND THIS WILL TAKE SEVERAL HOURS OF MOISTENING
BEFORE STEADIER SNOWS REACH THE CENTRAL/NRN PORTIONS OF THE STATE.
REMAINING DRY IN NRN NY UNTIL LATE MORNING/EARLY AFTERNOON AND
MAINLY EASTERN PORTIONS OF CLINTON/ESSEX COUNTIES.

OLD RULE OF THUMB THAT USUALLY WORKS WELL HERE IS NOT TO GO TOO
EXTREME ON SNOWFALL TOTALS IF SOUTH COASTAL NEW ENGLAND IS BEARING
THE BRUNT OF THE STORM. RARELY TO WE SEE HEAVY SNOW SWATHS IN
EXCESS OF 200 MI AND THIS STORM WILL BE NO EXCEPTION. PAST
HISTORY ALSO SUGGESTS CLIPPER BOMBS GENERALLY UNDERPERFORM UP HERE
IN LIEU OF THE MORE CLASSIC GULF COAST/SOUTHEASTERN SEABOARD
SYSTEMS AS LONGITUDINAL DEVELOPMENT TYPICALLY OCCURS A BIT TOO FAR
EAST FOR US. IN ANY REGARD FELT THIS MORNINGS NAM HAD THE BEST
HANDLE ON CURRENT SITUATION AND USED ITS SOLUTION IN TANDEM WITH
BLENDED CAM QPF OUTPUT TO ARRIVE AT POP/SNOWFALL GRADIENTS ACROSS
OUR AREA. GFS IDEA BIASED ABOUT 50 MI TOO FAR SOUTH AND EAST AND
EURO QPF TOO SPREAD OUT WITH ITS COARSER RESOLUTION DESPITE A
FAIRLY ACCURATE DEPICTION OF LOW TO MID LEVEL FEATURES.

WHAT THIS ALL SPELLS IS A STEADY 5-10/6-12 INCH SNOWFALL FOR OUR
SOUTHERNMOST COUNTIES...WITH A FAIRLY QUICK DROP OFF IN SNOW
TOTALS NORTH AND WEST. A SW-NE ORIENTED BAND OF 3-7 INCHES STILL
PROGGED FROM ABOUT MIDDLEBURY NORTHEASTWARD THROUGH MONTPELIER AND
ST JOHNSBURY...AND A GENERAL 1-3 INCH SNOWFALL FROM ESSEX COUNTY
NY NORTHEAST INTO THE BURLINGTON/PLATTSBURGH VICINITY AND ST
ALBANS/FRANKLIN COUNTY. LITTLE IF ANY ACCUMULATION FROM A SARANAC
LAKE TO MALONE LINE WEST. THIS IS MORE OR LESS STAYING THE COURSE
AND WE`RE NOW INTO THE WAIT AND SEE TIMEFRAME TO SEE HOW THIS ALL
PANS OUT. ALL ADVISORIES/WARNINGS REMAIN IN PLACE WITH NO CHANGES
NEEDED AT THIS TIME.

BY TONIGHT OCCLUDED CYCLONE CONTINUES ITS TREK SLOWLY NORTHEAST
TOWARD YARMOUTH, NS WITH WESTERN EDGE OF PCPN GRADUALLY FADING AWAY
ACROSS OUR AREA AS DEEPER LIFT AND DYNAMICAL SUPPORT FOR PCPN WANE.
SOME LIGHT TAIL-END ACCUMULATIONS POSSIBLE NORTH AND
EAST...OTHERWISE TRENDING DRY OVERNIGHT. DID ADJUST LOW TEMPERATURES
A TAD MILDER THAN PREVIOUS FORECASTS GIVEN CONTINUED OVERCAST SKIES
AND NEAR NEUTRAL THERMAL ADVECTIVE PROCESSES...MAINLY POSITIVE
SINGLE DIGITS...LOCALLY A BIT COLDER FAR WEST WHERE SOME PARTIAL
CLEARING MAY OCCUR LATE.

&&

.SHORT TERM /WEDNESDAY/...
AS OF 321 AM EST TUESDAY...HIGH PRESSURE THEN BUILDS EAST INTO
THE REGION BY WEDNESDAY WITH SKIES TRENDING CLEAR TO PARTLY CLOUDY
THROUGH THE COURSE OF THE AFTERNOON. DRY WEATHER CONDITIONS
EXPECTED WITH BLENDED MOS NUMBERS SUPPORTING HIGH TEMPERATURES
GENERALLY IN THE TEENS...PERHAPS LOWER 20S FAR SOUTH.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
AS OF 314 AM EST TUESDAY...DRY WEATHER TO START THE PERIOD AS
RIDGE OF HIGH PRESSURE AND ALOFT RESIDES OVER THE REGION WEDNESDAY
NIGHT. EARLY THURSDAY, THE RIDGE SLIDES EASTWARD WITH SOUTHERLY
FLOW DEVELOPING OVER THE REGION, INCREASING MOISTURE AND
MODERATING TEMPERATURES AHEAD OF A CLIPPER SYSTEM APPROACHING FROM
THE GREAT LAKES REGION. WHILE GFS AND ECMWF AGREE THAT
PRECIPITATION SHIELD WILL ENTER OUR WESTERN ZONES THURSDAY
AFTERNOON, THERE AREA DIFFERENCE REGARDING THE TRACK OF THE SFC
LOW AND THE PROGRESSION OF THE ASSOCIATED MID LEVEL TROUGH. THIS
LOW LOOKS TO BRING SNOW TO THE REGION THROUGH AT LEAST FRIDAY
EVENING. MID LEVEL TROUGH BECOMES NEGATIVELY TILTED ACCORDING TO
BOTH MODELS, THEREFORE AM FAVORING A SLOWER DEPARTURE OF
PRECIPITATION FROM NORTHEASTERN VERMONT AS DEPICTED BY THE ECMWF.
EXPECTING SOME LINGERING POPS INTO EARLY SATURDAY MORNING, BUT
NORTH/NORTHWEST FLOW BEHIND THIS SYSTEM WILL BRING IN DRIER AIR.
SO EXPECT SATURDAY TO BE MOSTLY DRY AT THIS POINT. AT THIS POINT,
EXPECT POTENTIAL SNOWFALL TOTALS TO RANGE FROM 2 TO 5 INCHES.

ANOTHER SYSTEM DEVELOPING IN THE MISSISSIPPI VALLEY WILL MOVE
NORTHEASTWARD LATE SUNDAY INTO MONDAY...BRINGING ANOTHER CHANCE
FOR SNOW FOR THE BEGINNING OF NEXT WEEK.

TEMPERATURES WEDNESDAY NIGHT WILL BE GENERALLY IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO. TEMPERATURES MODERATING IN THE
SOUTHERLY FLOW THURSDAY THROUGH FRIDAY WITH MAXES IN THE 20S AND
MINS IN THE TEENS TO L20S. BEHIND THE CLIPPER LOW, COLD AIR WILL
RETURN WITH MINS OF -15F TO ZERO FOR THE REST OF THE PERIOD. MAXES
WILL REACH SINGLE DIGITS TO MID TEENS SATURDAY THROUGH MONDAY.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z WEDNESDAY...VFR CONDITIONS WILL DETERIORATE TO MVFR
AS SNOW SPREADS NORTHWESTWARD THIS MORNING. EXPECT MVFR
CONDITIONS AND SNOW TO MOVE INTO KRUT BETWEEN 12-15Z...KMPV 13-
15Z...KBTV/KPBG 15Z-17Z...AND KSLK 16Z-18Z. KMSS WILL BE FAR
ENOUGH NORTH AND WEST TO REMAIN VFR. SOME EMBEDDED MODERATE SNOW
IS POSSIBLE WITH IFR/LIFR CONDITIONS AFFECTING KRUT/KMPV 14Z-
22Z...KBTV/KPBG 17Z-21Z AND KSLK 18Z-23Z.

SNOW WILL LIGHTEN AND DIMINISH THIS EVENING WITH MOSTLY DRY
CONDITIONS SETTLING IN AFTER MIDNIGHT/05Z. EXPECT CONDITIONS TO
IMPROVE TO MVFR/VFR AS SNOWFALL COMES TO AN END.

NORTH TO NORTHEAST WINDS OF 6-12KTS WILL INCREASE AND BECOME
GUSTY AROUND 25KTS BY MID MORNING. THIS WILL RESULT IN THE
POTENTIAL FOR AREAS OF BLOWING/DRIFTING SNOW, ESPECIALLY AT RUT
AND MPV WHERE DURATION OF MODERATE SNOW WILL BE LONGEST. EXPECT
GUSTS TO SUBSIDE HEADING INTO TUESDAY EVENING.

OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...

12Z WEDNESDAY THROUGH 12Z THURSDAY...MAINLY VFR CONDITIONS
EXPECTED AS RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION.

12Z THURSDAY THROUGH 00Z SATURDAY...TRENDING IFR/MVFR IN LIGHT
SNOW AS LOW PRESSURE MOVES EAST FROM THE OHIO VALLEY/GREAT LAKES
STATES.

00Z SATURDAY THROUGH 00Z SUNDAY...VFR CONDITIONS EXPECTING AS A
RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION.

&&

.EQUIPMENT...
AS OF 122 PM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED NEAR
WATERTOWN NEW YORK WILL BE DOWN AT LEAST THROUGH TUESDAY. THIS IS
DUE TO A PEDESTAL DYNAMIC FAULT. ELECTRONICS TECHNICIANS HAVE
ORDERED NEW PARTS TO FIX THIS PROBLEM. HOWEVER...THE NEW PARTS
HAVE NOT ARRIVED AS OF THIS TIME AND THE KTYX RADAR WILL LIKELY
NOT BE RESTORED TO SERVICE UNTIL SOMETIME THIS WEEK.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 1 AM EST WEDNESDAY FOR VTZ010>012-
     019.
     WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR VTZ004-
     007>009-018.
NY...NONE.

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
EQUIPMENT...WFO BTV


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