FXUS61 KBTV 090748
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
247 AM EST WED DEC 9 2009
.SYNOPSIS...
A STRONG STORM SYSTEM WILL BRING A VARIETY OF WINTRY WEATHER TO THE
REGION TODAY INTO THIS EVENING...WITH SNOW...MIXED PRECIPITATION AND
GUSTY WINDS EXPECTED. PRECIPITATION WILL TAKE ON A MORE SHOWERY
CHARACTER BY LATER TONIGHT AS A STRONG COLD FRONT SWEEPS
EASTWARD ACROSS THE AREA. BEHIND THIS FRONT GUSTY WEST WINDS ARE
EXPECTED THURSDAY INTO FRIDAY ALONG WITH SCATTERED TO NUMEROUS SNOW
SHOWERS...ESPECIALLY ACROSS THE MOUNTAINS AND LAKE ONTARIO SNOWBELTS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 247 AM EST WEDNEDAY...VERY COMPLEX AND CHALLENGING FCST TAKING
SHAPE FOR TODAY AS DEEP LOW PRESSURE TRACKS THROUGH THE GREAT LAKES
STATES DRIVING LARGE SCALE ASCENT NORTHEASTWARD ACROSS OUR AREA.
IMPRESSIVE DYNAMICAL SETUP WITH VERY STRONG WAA/ISENTROPICALLY
DRIVEN QPF EXPECTED IN MOST AREAS. HOWEVER...ADDING COMPLEXITY TO
OVERALL SITUATION WILL BE DEGREE OF LOW TO MID LVL WARMING THAT
OCCURS AT MID LVLS (925-850 MB) LATER THIS AFTERNOON AS PCPN SHIELD
PUSHES NORTHEASTWARD AND DEGREE TO WHICH VERY STRONG SERLY WIND
FIELDS INFLUENCE INTENSITY AND AMOUNTS OF PCPN. I'M LEANING CLOSER
TO NAM/4KM WRF SOLNS HERE AS THESE MODELS APPEAR TO HAVE BEST HANDLE
ON EVOLUTION OF LOW TO MID LVL THERMAL PROFILES. THEREFORE...PCPN
SHOULD START AS SNOW AND COME IN VERY QUICKLY FROM SW TO NE DURING
THE EARLY TO MID MORNING HOURS...WHICH WILL LIKELY CAUSE
CONSIDERABLE HEADACHES DURING THE MORNING COMMUTE. WITH SUCH STRONG
SERLY FLOW AT MID LVLS...WILL HIGHLIGHT HEAVIEST QPF ON THE
WINDWARD...IN THIS CASE EASTERN SLOPES OF OUR DACKS/GREENS WHERE
FLOW IS FORCED SHARPLY UPWARD. CONSIDERABLY LESS QPF EXPECED IN
CHVLY AND WESTERN SLOPES OF THE NRN GREENS WHERE STRONG
COMPRESSIONAL DOWNSLOPING SIGNATURE QUITE EVIDENT ON THIS MORNING'S
00Z 4KM WRF RUN. AS WARM NOSE SURGES NORTHWARD LATER TODAY...PCPN
LIKELY TO TAKE ON A MIXED CHARACTER BEFORE TAPERING OFF IN INTENSITY
TOWARD EVENING...ESP ACROSS SWRN VT AND INTO THE WRN DACKS/SRN SLV
AS PRONOUNCED DRY SLOT PUSHES EASTWARD. ELSEWHERE...PROFILES MORE
CONFLICTING AND GIVEN THAT MANY AREAS OF ERN VT ARE GETTING OFF TO A
COLD START...MUCH OF THE QPF TODAY WILL LIKELY FALL AS SNOW. AFTER
RUNNING SEVERAL ALGORITHMS...SNOW TOTALS END UP FAIRLY SIMILAR TO
PRIOR FCST SHOWING GENERAL 4-8 INCH AMOUNTS ACROSS THE ERN SLOPES OF
THE GREENS...3-6 INCHES IN THE ST LAWRENCE AND CHAMPLAIN
VALLEYS...AND 5 TO 10 INCHES IN THE DACKS. HIGH TEMPS ALSO TRICKY
HERE...BUT GENERALLY EXPECTING VALUES IN THE L-M30S BY LATER IN THE
DAY...WITH SLIGHTLY COOLER READINGS ACROSS NERN VT.
NOW FOR THE WINDS. PERUSAL OF LATEST BNDRY LYR SOUNDING PROFILES
THIS MORNING HAS ME QUITE CONCERNED FOR AREAS ALONG THE WESTERN
SLOPES OF OUR GREEN MOUNTAINS...ESP IN ADDISON AND RUTLAND COUNTIES.
WITH LATEST WRF RUN SHOWING SERLY FLOW OF 60-70 KTS BELOW 2 KFT IN
THESE AREAS...COULD EASILY SEE GUSTS TO 60 MPH OR EVEN A TAD
STRONGER FROM DANBY TO NORTH CLARENDON...NORTH INTO THE EASTERN
SIDE OF RUTLAND CITY...RIPTON AND LINCOLN. BASED OFF THIS LATEST
INFORMATION...WILL MAINTAIN HIGH WIND WARNINGS AS IS THOUGH ADD
WESTERN RUTLAND AND LAMOILLE COUNTIES WITH POWER OUTAGES AND TREE
DAMAGE LIKELY IN THESE LOCALES. BEST ESTIMATE FOR TIMING OF
STRONGEST WINDS WOULD BE FROM 14Z-22Z TODAY. ELSEWHERE...GUSTY TO
OCCASIONALLY STRONG WINDS ALSO POSSIBLE ALONG THE WESTERN SLOPES OF
THE DACKS IN NRN NY AND TO THE LEE OF WHITE MOUNTAINS AND INTO THE
HIGHER ELEVATIONS OF NERN VT. HOWEVER...WITH WINTER STORM WARNINGS
IN EFFECT FOR THESE AREAS AND OWING TO THE FACT THAT MAGNITUDE OF
GUSTS LIKELY A TAD LESS...WILL MINIMIZE COMPLEXITY HERE AND KEEP
DISCRETE MENTION OF THESE WINDS IN THE WINTER WEATHER STATEMENTS FOR
THESE AREAS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 247 AM EST WEDNESDAY...BY TONIGHT BEST FORCING PUSHES NORTH
AND EAST OF THE REGION AS DRY SLOT CONTINUES TO PUSH EASTWARD ACROSS
THE CENTRAL/SRN PORTIONS OF THE FCST AREA. THEREFORE PCPN WILL TAKE
ON A MORE DRIZZLY/SHOWERY CHARACTER AS TEMPS HOLD STEADY OR SLOWLY
RISE THROUGH THE EVENING HOURS. WILL MAINTAIN DECENT CHC TO LIKELY
POPS HERE...BUT AGAIN ADDL PCPN WILL BE MUCH LIGHTER. STRONG SFC
COLD FRONT THEN PUSHES WEST TO EAST ACROSS THE AREA LATER AT NIGHT
WITH FLOW VEERING FROM SOUTH TO WEST/SOUTHWEST AND CAA BEGINNING IN
EARNEST. WILL OFFER A BLEND OF MOS GUIDANCE FOR MINS HERE WITH AGAIN
TEMPS HOLDING STEADY THROUGH THE EVENING...THEN FALLING DURING THE
LATER OVERNIGHT HOURS TOWARD MORNING.
THEREAFTER...PRIMARY WEATHER WILL FEATURE MORE GUSTY WINDS AND
SCT/NUMEROUS MTN/LK EFFECT SHSN. POST-FRONTAL WESTERLY FLOW LIKELY
TO BE QUITE GUSTY DURING THURSDAY WITH GUST SPEEDS EASILY ECLIPSING
35 MPH...ESP IN FAVORED AREAS OF THE SLV AND CT RVR VALLEY WHICH
TEND TO SEE HIGHER SPEEDS IN THESE REGIMES. AS MEAN 925-850 MB TEMPS
FALL SHARPLY DURING THE DAY...LAKE EFFECT AND OROGRAPHICALLY
ENHANCED SHSN SHOULD BLOSSOM CONSIDERABLY WITH ADDL ACCUM
LIKELY...ESP IN THE LK ONTARIO SNOWBELTS OF SRN ST LAWRENCE/SRN
FRANKLIN COUNTIES. TEMPS REALLY GOING NOWHERE AND WILL HIGHLIGHT
READINGS ONLY A TAD ABOVE PRIOR NIGHT'S MINS IN THE GRIDDED DATASET.
BY THURSDAY NIGHT INTO FRIDAY WINDS SLOWLY ABATE THOUGH WITH P-GRAD
REMAINING FAIRLY TIGHT...CONDS STILL LIKELY TO BE BREEZY IN MANY
AREAS. OF MORE CERTAINTY WILL BE THE CONTINUATION OF LK EFFECT AND
MTN SHSN WHERE ADDL ACCUM LIKELY TO THE LEE OF LK ONTARIO WHERE
FUTURE HEADLINES MAY BE NEEDED. TEMPS WILL RUN ON THE CHILLY SIDE
WITH LOWS 14 TO 22 AND HIGHS 18 TO 26.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 157 PM EST TUESDAY...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 ENTIRE CWA BASED ON WIND REGIME. 850
TEMPS DURING THIS TIMEFRAME VARY VERY SLIGHTLY. NEXT SFC LOW 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 /07Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...CLDS WILL CONT TO INCR OVERNIGHT...WITH
CIGS LOWERING AS WELL...THOUGH CONDS WILL REMAIN VFR THRU ABOUT
10Z. SN WILL DEVELOP ACRS THE REGION BTWN 09Z-11Z WITH CONDS
LOWERING RAPIDLY TO IFR/LIFR...WITH PERIODS OF MOD TO HVY SN FROM
13Z-20Z. WARMER AIR MOVING IN ALOFT AT 925 MB WILL CHANGE THE SN
OVER TO SLEET...OR A MIX OF SNOW AND SLEET AFT 18Z...AND THEN
CHANGING TO RN IN THE 20Z-21Z TIME RANGE. MODEL GUIDANCE
SUGGESTING BELOW FREEZING TEMPS AT THE SFC COULD PERSIST ACRS THE
ST LAWRENCE VALLEY AND ESTRN VT THRU 00Z THU...SO SOME AREAS
COULD POTENTIALLY SEE SOME FRZ RA. HOWEVER...CONFIDENCE IS LOW AT
THIS TIME FOR FRZ RA. STILL HAVE SOME UNCERTAINTY AS TO THE EXACT
TIMING OF WHEN SN WILL CHANGE TO SLEET AND RA THIS
AFTERNOON...BUT LOOKS LIKE IT WILL BE AROUND 20Z. WRF MODEL
SHOWING DRY SLOT WORKING INTO THE AREA...ESPECIALLY ACROSS
VT...BY ABOUT 02Z OR 03Z. LATEST MODEL GUIDANCE ALSO SHOWING
STRONG SOUTHEAST WINDS ALOFT...SO GOOD POTENTIAL FOR LOW LEVEL
WIND SHEAR TO DEVELOP ACROSS THE REGION AFTER 12Z WEDNESDAY AND
CONTINUE THROUGH 00Z THURSDAY. HAVE INDICATED DRY SLOT MOVING
INTO THE REGION AROUND 02Z OR 03Z...BUT CIGS SHOULD REMAIN LOW
WITH SOME BR AS WELL.
06Z THURSDAY THROUGH SUNDAY...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 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 AND MOST OF SUNDAY...AS A RIDGE OF HIGH PRESSURE BUILDS
BACK INTO THE REGION. AREAS OF MVFR IN SCATTERED SNOW SHOWERS
ACROSS NORTHERN NEW YORK LATE SUNDAY AFTERNOON.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR VTZ003-
004-006>008-010-012-018-019.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
VTZ001-002-005-009-011-016-017.
HIGH WIND WARNING FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR VTZ006-011-016>019.
NY...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
NYZ029>031-034.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ026>028-035-087.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...JN
AVIATION...WGH/NEILES
