FXUS61 KBTV 082123
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
423 PM EST TUE DEC 8 2009
...SIGNIFICANT STORM TO IMPACT THE REGION THE NEXT FEW DAYS -
HEAVY SNOWS AND AN EXTENDED PERIOD OF STRONG WINDS WILL BE THE
PRIMARY RESULTS...
.SYNOPSIS...
A STRONG STORM SYSTEM WILL BRING A WIDE VARIETY OF WEATHER TO THE
NORTH COUNTRY WEDNESDAY THROUGH FRIDAY. WEDNESDAY WILL FEATURE
HEAVY SNOW...ESPECIALLY DURING THE FIRST HALF OF THE DAY BEFORE
BECOMING A MIX OF PRECIPITATION. STRONG WINDS WILL ALSO AFFECT THE
GREEN MOUNTAINS. STRONG GUSTY WINDS ALONG WITH SNOW SHOWERS WILL
IMPACT THE ENTIRE REGION WEDNESDAY NIGHT THROUGH FRIDAY. TRAVEL
WILL BE DIFFICULT...AND SCATTERED POWER OUTAGES ARE POSSIBLE.
&&
.NEAR TERM /UNTIL 6 PM WEDNESDAY EVENING/...
AS OF 350 PM EST TUESDAY...SORRY FOR THE DELAY IN GETTING THIS
OUT. NOT AN EASY FORECAST BY ANY STRETCH OF THE IMAGINATION AND
LOTS OF ITEMS TO CONSIDER. SO I'LL GET RIGHT TO IT.
TONIGHT...FAIRLY QUIET. CLOUDS INCREASE LATE. TEMPS WILL NOSEDIVE
EARLY THIS EVENING...AND THEN AFTER MIDNIGHT BEGIN TO INCREASE.
NO BIG CHANGES TO MODEL GUIDANCE BUT A FEW SUBTLE ITEMS HAVE
CHANGED...AND THOSE SUBTLE THINGS DO HAVE BIG IMPACTS. STILL
FOLLOWING GFS SD NAM SEEMS TO BE OVERLY AGRESSIVE WITH
REDEVELOPMENT ALONG THE COAST TOMORROW. GFS HAS TRENDED A BIT
COLDER WHICH HAS BIG IMPLICATIONS ON PRECIP FORECAST AND SNOW
AMOUNTS. GIVEN TODAY HAS BEEN RUNNING COOLER THAN EARLIER GUIDANCE
AND SOME CHILLY TEMPS AND LOW DEWPOINTS JUST TO OUR NORTH...IT'S
PRUDENT TO FOLLOW THE COLDER TREND. VERY IMPRESSIVE DYNAMICS --
BOTH THERMAL AND JET VARIETY -- WILL RAPIDLY DEVELOP ACROSS THE
REGION LATE TONITE. EXPECT BURST OF WARM AIR ADVECTIONS SNOWS TO
RAPIDLY DEVELOP FROM SW TO NE AFTER 06Z. TOMORROWS MORNING DRIVE
WILL BE A MESS. SEVERAL INCHES ALREADY ON THE GROUND AND SNOWFALL
RATES OF 1"/HR OR MORE. IMPRESSIVE 850MB JET OF 66-85KTS WILL
BRING WARMER AIR IN ALOFT...BUT IT WONT BE UNTIL EARLY AFTERNOON.
BY THAT TIME THE BULK OF THE PRECIP WILL BE OVER WITH. STILL
EXPECTING A MIX OF RAIN/FREEZING RAIN/SLEET FOR MANY AREAS AT SOME
POINT. THE GRIDDED FORECAST DATABASE IS A MESS BECAUSE OF IT.
WITH SLIGHTLY COLDER SCENARIO...HAVE BUMPED SNOWFALL ACCUMLATIONS
UP A COUPLE OF INCHES. THIS HAS REQUIRED ISSUANCES OF WINTER STORM
WARNINGS AND CONTINUATION OF ADVISORIES.
HOW MUCH SNOW WILL FALL IS STILL A TOUGH QUESTION AND FORECAST IS
RATHER LOW CONFIDENCE. MODELS CAME IN WITH HIGHER QPF...ON ORDER
OF 1 TO 1.5" THRU 00Z THURSDAY. THAT IS A BIT DISCONCERTING AND
WOULD MEAN WELL OVER A FOOT OF SNOW IN MANY LOCATIONS. FEEL THAT
MODELS ARE BIT TOO AGRESSIVE AND CUT BACK TO 0.60 TO 0.75IN QPF.
HOWEVER ADDED IN OROGRAPHIC EFFECTS WHICH WILL BE
CONSIDERABLE...AND THE RANGE GOES FROM 0.3 INCHES IN SHADOWED
LOCATIONS DOWNWIND OF ADIRONDACKS...GREEN AND WHITE MOUNTAINS.
HOWEVER QPF GOES UP TO ABOUT 1IN IN FAVORED UPSLOPE REGIONS OF ERN
GREENS AND DACKS.
NET RESULT IS 6 TO 10 INCHES IN SOUTH CENTRAL VT TO PERHAPS A FOOT
ON EASTERN SIDE OF ADIRONDACKS...AND 3 TO 5 INCHES IN THE
VALLEYS/NE VERMONT. HOWEVER...IF THE MODELS ARE CORRECT THIS
FORECAST IS UNDERPLAYING TOTAL SNOW. OR IF WARMER AIR GETS IN TOO
QUICKLY...THEN THE FORECAST IS OVERPLAYING TOTAL SNOW. I THINK YOU
GET THE PICTURE.
OTHER BIG PROBLEM WILL BE WINDS ALONG THE SPINE AND WESTERN SLOPES
OF THE GREENS. HAVE THOSE STRONG WINDS ALOFT...TUCKED UNDER THE
INVESION ALOFT AND JUST ABOVE SUMMIT HEIGHT. THATS A GOOD RECIPIE
FOR BREAKING WAVES IN THE ATMOSPHERE AND STRONG DOWNSLOPE WINDS.
THINKING 60MPH GUSTS NOT OUT OF THE QUESTION. HAVE GONE HIGH WIND
WARNING FOR THE SPINE...BUT THREW IN WIND ADVISORY FOR A FEW
NEARBY AREAS THAT ALSO GET HIT WITH SUCH WINDS...NAMELY RUTLAND
AREA AND WESTERN LAMOILLE COUNTY.
&&
.SHORT TERM /6 PM WEDNESDAY EVENING THROUGH THURSDAY NIGHT/...
AS OF 350 PM EST TUESDAY...THE BIG STORY FOR THE PERIOD WILL BE
WIND...WIND...WIND AND SOME PERSISTANT LAKE EFFECT BANDS AND SNOW
SHOWERS. STRONG LOW PRESSURE WILL BE MOVING NORTH OF US ACROSS
QUEBEC BUT NOT ALL THAT FAST. REGION STAYS IN TIGHT PRESSURE
GRADIENT. WITH COLD AIR ADVECTION LEADING TO EXCELLENT
MIXING...WE'LL BE TAPPING INTO A LOT OF STRONG WINDS AREA WIDE.
SUSPECT WIND ADVISORY WILL BE NEEDED FOR THE ENTIRE REGION BUT
LETS GET THRU THE STUFF TOMORROW FIRST. PER BUFKIT SOUNDING
ANALYSIS...ENTIRE REGION SHOULD SEE FREQUENT GUSTS OF 35 TO 45 MPH
FROM LATE WEDNESDAY NIGHT ALL THE WAY INTO FRIDAY. THIS WILL
LIKELY LEAD TO ADDITIONAL POWER OUTAGES AND DOWNED TREES.
WINDS AND INSTABILITY WILL LINE UP TO PRODUCE A LONG LASTING SEMI-
PERMANENT LAKE EFFECT SNOW PLUME OFF OF LAKE ERIE THURSDAY. THIS
SHOULD BE ORIENTED TOWARD THE EAST/EAST NORTHEAST. WE COULD SEE
SOME HEFTY ACCUMULATIONS ACROSS EXTREME SOUTHERN ST LAWRENCE AND
FRANKLIN COUNTIES. LAKE PLUME SHOULD ALSO MAKE IT ACROSS ESSEX
CNTY NY AND INTO VERMONT...PROBABLY ADDISON COUNTY. SUSPECT WE
WILL NEED SOME WINTER STORM WARNINGS/ADVISORIES FOR THAT FEATURE.
BUT AGAIN...LETS GET THRU THE FIRST PART OF THE STORM FIRST.
HAVENT TALKED AT ALL ABOUT TEMPS. FOLLOWED GUIDANCE WITH THIS.
TEMPS WILL FALL TO BELOW NORMAL LEVELS FOR THURSDAY AS 850MB TEMPS
CONTINUE TO COOL TO -10 TO -12C LEVELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 157 PM EST TUESDAY...ON BACKSIDE OF EXITING SYSTEM FOR FRIDAY...
CWA WILL BE UNDER WNW FLOW ALLOWING FOR PERSISTENT -SW WHICH WILL
TAPER OFF FROM W TO E AS LOW PRESSURE SYSTEM HEADS INTO THE
CANADIAN MARITIMES. W/ SFC RIDGE SETTING UP OVER THE MID-ATLANTIC
REGION...FRI NGT INTO SAT WILL HAVE WINDS SHIFT TO MORE
WESTERLY...ALLOWING FOR LK EFFECT SNOW POTENTIAL ESPECIALLY FOR N
NY NEAR LK ONTARIO. RIDGE DOES BUILD N INTO THE REGION SAT NGT
INTO SUNDAY FOR A NICE CD DAY FOR THE CWA. HAVE KEPT FAIRLY
CONSISTENT HIGHS/LOWS FOR ENITRE CWA BASED ON WIND REGIME. 850
TEMPS DURING THIS TIMEFRAME VARY VERY SLIGHTLY. NEXT SF CLOW TO
AFFECT THE NORTH COUNTRY WILL BUILD ACROSS THE CWA BY SUN AFTNOON.
EXPECTING QPF TO BE LGT BASED ON SFC LOW TRACK TO THE N...BUT WITH
CD POOL OF 850 TEMPS DROPPING DOWN TO -22C/-26C BY EVENING FROM
DAY HIGHS NEAR -8C. POTENTIAL FOR SNOW SQUALLS/FLASH FREEZE AS
THIS PUSHES E...ESPECIALLY FOR NORTHERN PORTIONS OF THE CWA. W/
THIS FROPA...WINDS SHIFT TO THE NNW ALLOWING FOR LEFTOVER UPSLOPE
-SW MONDAY MORNING...CLRING BY MDDAY AS HIGH PRESSURE BUILDS E
OVER THE AREA AND REMAINING INTO TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...SCT VFR LL CLD COVER WILL GIVE WAY TO SCT-
BKN120 AHEAD OF NEXT WX SYSTEM. THIS MID/HIGH CLD COVER WILL WORK
NE INTO THE AREA BY 00Z WED. BY 06Z WED MORE LOW CLDS WORK NE AND
EVENTUALLY LEAD TO CEILINGS LWRING FROM VFR DOWN TO LFR/LIFR AS
LGT SNOW DEVELOPS THRU 11Z. DURING THIS TIME VSBY VARYING FROM
2-5SM. HEAVIER BURST OF SNOW AFT 11Z-12Z THAT WILL BRING VSBY DOWN
TO LESS THAN 1SM AT TIMES THRU 16Z. SFC SYSTEM WILL BEGIN TO SHIFT
HEAVIEST PRECIP N OF THE AREA BY 16Z SO WILL TREND INCR VSBY. SOME
WARM AIR ALOFT WILL ALSO HELP TO SLACKEN PRECIP. WINDS WILL BE
OTHER ISSUE DURING LATTER HALF OF FORECAST PERIOD. STRONG JET
ALOFT WILL BRING SUSTAINED WINDS 15-30KTS FROM MAINLY FROM THE SSE
(ENE-ESE IN N NY). WINDS SHEAR 45-55KTS POSSIBLE FROM 09Z-
14Z...ESPECIALLY OVER RUT/MPV/SLK.
18Z WEDNESDAY THROUGH SATURDAY...MODERATE TO BRIEFLY HEAVY SNOW IS
EXPECTED 12-18Z WEDNESDAY...FOLLOWED BY A MIX OF SLEET AND RAIN
BEFORE STEADY PCPN ABATES TOWARD EVENING WITH LINGERING AREAS OF
DRIZZLE. WINDS SHIFT INTO THE WEST WEDNESDAY NIGHT ALLOWING FOR
SCATTERED SNOW SHOWER ACTIVITY AS COLDER AIR WORKS BACK INTO THE
REGION. GUSTY SELY WIND CONDITIONS ARE ALSO EXPECTED MUCH OF WED
AND WED NIGHT...ESPECIALLY AT KRUT...WITH SELY GUSTS 40+KT POSSIBLE.
LOW PRES DEPARTS TO THE NORTH ON THURSDAY WITH STRONG WEST WINDS
DEVELOPING 15-25 KT WITH GUSTS 30 KT AND SCATTERED SNOW SHOWER
ACTIVITY PRODUCING LOCALIZED IFR CONDITIONS. A FEW SNOW SHOWERS
MAY LINGER INTO FRIDAY. VFR ON SATURDAY...AS A RIDGE OF HIGH
PRESSURE BUILDS BACK INTO THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING FROM 4 AM TO 10 PM EST WEDNESDAY FOR
VTZ004-006>008-010-012-019.
WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM EST WEDNESDAY FOR
VTZ001>003-005-009-011-016>018.
HIGH WIND WARNING FROM 7 AM TO 7 PM EST WEDNESDAY FOR
VTZ016>019.
WIND ADVISORY FROM 7 AM TO 7 PM EST WEDNESDAY FOR VTZ006-011.
NY...WINTER STORM WARNING FROM 4 AM TO 10 PM EST WEDNESDAY FOR
NYZ029>031-034.
WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM EST WEDNESDAY FOR
NYZ026>028-035-087.
&&
$$
SYNOPSIS...NASH
NEAR TERM...NASH
SHORT TERM...NASH
LONG TERM...JN
AVIATION...BANACOS/JN
