FXUS61 KBTV 010209
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
909 PM EST MON NOV 30 2009
.SYNOPSIS...
A RIDGE OF SURFACE HIGH PRESSURE WILL GRADUALLY BUILD INTO THE NORTH
COUNTRY OVERNIGHT...RESULTING IN DIMINISHING NORTH WINDS AND
PARTIAL CLEARING TOWARD DAYBREAK. ANY LINGERING SNOW SHOWER OR
FLURRY ACTIVITY WILL BE LIGHT AND MAINLY CONFINED TO THE MOUNTAINS
TONIGHT. A WEAKENING UPPER LEVEL DISTURBANCE WILL MOVE SOUTHEASTWARD
ACROSS THE REGION TUESDAY RESULTING IN LIGHT SNOW SHOWERS...MAINLY
ACROSS THE NORTHERN ADIRONDACKS. AFTER A PLEASANT AND SEASONABLE DAY
WEDNESDAY...A STRONG LOW PRESSURE SYSTEM MOVES NORTHWARD FROM THE
TENNESSEE AND OHIO VALLEY REGION BRINGING RAINY AND WINDY
CONDITIONS TO THE NORTH COUNTRY WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 901 PM EST MONDAY...RADAR IMAGERY AND SURFACE OBS INDICATE
SCATTERED LIGHT SNOW SHOWERS CONTINUE ACROSS PORTIONS OF THE
FORECAST AREA. ABUNDANT CLOUD COVER IS ALSO LINGERING THIS
EVENING...ALTHOUGH SOME CLEARING CAN BE SEEN ACROSS PORTIONS OF
NEW YORK SOUTH AND EAST OF LAKE ONTARIO IN RESPONSE TO SURFACE
RIDGING. CURRENT TEMPERATURES ARE GENERALLY IN THE LOWER TO MID
30S WITH A FEW OF THE USUALLY COOL SPOTS IN THE 20S. WITH SOME
BREAKS IN THE OVERCAST EXPECTED THROUGHOUT THE
NIGHT...TEMPERATURES WILL DROP INTO THE MID AND UPPER 20S IN MOST
LOCATIONS WHILE THE ADIRONDACKS AND NORTHEAST KINGDOM WILL SEE THE
UPPER TEENS FOR LOWS. THE CURRENT FORECAST HAS THIS ALL
COVERED...SO NO UPDATE IS NEEDED THIS EVENING.
PREVIOUS DISCUSSION...
CLOUDY SKIES PREVAIL ACROSS THE NORTH COUNTRY THIS AFTN IN THE
WAKE OF THE SFC COLD FRONT WHICH SWEPT SEWD THRU THE FORECAST AREA
DURING THE MORNING HRS. PARTIAL CLEARING IS NOTED NORTH OF LAKE
ONTARIO...ASSOCIATED WITH LOW-LEVEL DRYING AND INCREASED
SUBSIDENCE WITH RIDGE AXIS IN PLACE ACROSS SERN ONTARIO. LOW-LEVEL
CAA WILL CONTINUE FOR SEVERAL MORE HRS WITH NWLY/NLY WIND REGIME.
SFC WINDS OF 5-10 MPH WILL GRADUALLY SUBSIDE THIS EVENING AS SFC
RIDGE BUILDS EWD...CRESTING OVER THE CHAMPLAIN VALLEY AROUND 06Z.
A FEW BREAKS IN THE OVERCAST CAN BE EXPECTED LATE TONIGHT PER
UPSTREAM OBS AND MODEL RH FIELDS...AND LIGHT WINDS MAY ALLOW FOR
INCREASED RADIATIONAL COOLING EFFECTS JUST BEFORE DAYBREAK. LOW
TEMPERATURES SHOULD RANGE FROM MID 20S ACROSS MOST VALLEY
LOCATIONS...AND IN THE UPR TEENS FOR THE NRN ADIRONDACKS AND FAR
NERN VT GIVEN EXPECTATION FOR PARTIAL CLEARING. OTHERWISE...HAVE
INCLUDED JUST A 20 PERCENT CHANCE OF A FEW LIGHT SNOW SHOWERS OR
FLURRIES...MAINLY THRU MIDNIGHT ASSOCIATED WITH SHALLOW
INSTABILITY AND MOISTURE. ANY LIGHT SNOW SHOWER ACTIVITY WILL
MAINLY BE CONFINED TO NWLY UPSLOPE FLOW AREAS OF THE NRN
ADIRONDACKS AND GREEN MTNS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 337 PM EST MONDAY...MAIN FORECAST ISSUE ON TUESDAY IS POTENTIAL LAKE
ENHANCED SNOWS FROM LAKE ONTARIO...AND NORTHWARD AND EWD EXTENT
OF THESE SNOW SHOWERS ACROSS ST. LAWRENCE AND FRANKLIN COUNTIES IN
NY. A WEAKENING SFC-700MB TROUGH TRACKS ESEWD FROM SERN ONTARIO AT
12Z TUESDAY INTO VT BY AFTN. THIS SYSTEM WILL BRING INCREASED MID-
LEVEL CLOUD COVER...BUT ALSO HELP TO STEEPEN LAPSE RATES VCNTY
LAKE ONTARIO WITH MEAN SFC-850MB WIND VECTORS BACKING TO 230DEG
AHEAD OF THE APPROACHING TROUGH. MOST GUIDANCE BRINGS LAKE ONTARIO
ENHANCED SNOW BAND AND MOISTURE ENEWD INTO SRN ST. LAWRENCE COUNTY
AND FRANKLIN COUNTY FOR SEVERAL HRS DURING THE DAY TUESDAY. WE
HAVE INCORPORATED THIS INTO THE FCST...WITH LOCALIZED D-2" SNOW
AMTS POSSIBLE...MAINLY IN SERN ST. LAWRENCE/SRN FRANKLIN COUNTIES
BEFORE BAND SHIFTS SWD AND WEAKENS. MOST OF THE ACCUMULATION WILL
BE ABOVE 1 KFT WITH VALLEY TEMPS GETTING ABOVE FREEZING TUESDAY
AFTN. ELSEWHERE...DECAYING NATURE OF UPR TROUGH SUGGESTS NOT MUCH
IN THE WAY OF PCPN OUTSIDE OF LAKE ENHANCED ZONE. INCLUDED 20-30
POPS FOR THE HIGHER ELEVATIONS OF VT DURING TUESDAY AFTN...BUT
LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. A BRIEF SPRINKLE OR
FLURRY IS POSSIBLE IN THE CHAMPLAIN AND CT RIVER VALLEYS TUES
AFTN. STAYED NEAR MAV/MET BLEND FOR HIGH TEMPERATURES...MAINLY MID
30S 1-2 KFT AND UPR 30S TO NEAR 40F IN THE IMMEDIATE CHAMPLAIN/ST.
LAWRENCE/CT RIVER VALLEY AREAS.
UPR TROUGH MOVES PAST TUESDAY NIGHT WITH HIGH PRESSURE IN CONTROL
MUCH OF TUESDAY NIGHT AND WEDNESDAY. VARIABLY CLOUDY SKIES AND
INCREASING 1000-500MB HEIGHTS/850MB TEMPS SHOULD KEEP LOWS
SEASONABLE TUESDAY NIGHT - MAINLY IN THE 20S. ON WEDNESDAY...PARTLY
SUNNY CONDITIONS ARE EXPECTED THRU EARLY AFTN WITH BROAD SLY TO SWLY
LOW-LEVEL FLOW RESULTING IN 850MB TEMPS WARMING TO NEAR +4C DURING
THE AFTN. TEMPERATURES SHOULD RECOVER NICELY WITH HIGHS IN THE LOW
TO MID 40S...EXCEPT AROUND 40 FOR THE NORTHEAST KINGDOM OF VT.
CLOUDS STEADILY INCREASE MID-LATE AFTN WEDNESDAY WITH APPROACH OF
STRONGER ISENTROPIC ASCENT ASSOCIATED WITH TN/OH RIVER VALLEY LOW
PRESSURE CENTER. USED 15Z SREF CONSENSUS TO INDICATE A CHANCE OF
RAIN SHOWERS REACHING OUR SWRN FORECAST AREA DURING THE 21-00Z
PERIOD.
12Z NWP SUITE CONTINUES TO FAVOR AN INLAND STORM TRACK WITH RATHER
INTENSE LOW PRESSURE TRACKING NWD ACROSS ERN OH AND WRN NY
STATE...WITH THE NORTH COUNTRY IN STRONG SOUTHERLY DEEP LAYER FLOW
AND WARM ADVECTION WEDNESDAY NIGHT. THE GFS SHOWS CENTRAL PRESSURE
OF THE LOW DOWN TO 983MB AS LOW PASSES NEAR KROC AT 12Z THURSDAY.
850MB TEMPS WARM TO NEAR +10C ACROSS THE NORTH COUNTRY. LOWS
WEDNESDAY NIGHT SHOULD GENERALLY REMAIN IN THE 40S...AND MAY WARM
OVERNIGHT WITH STRONG SLY FLOW. HAVE SHOWN POPS 80-90 PERCENT RANGE
BASED ON GOOD MODEL CONSISTENCY AND POTENTIAL FOR AT LEAST MODERATE
INTENSITY PCPN AS BEST WAA ASSOCIATED LIFT PASSES THRU THE REGION.
RAINFALL AMTS OF A HALF INCH TO AN INCH ARE POSSIBLE THRU 12Z
THURSDAY...AS DRY SLOT BEGINS TO WORK INTO THE REGION FROM THE SW.
DO NOT FORESEE ANY WINTER WEATHER CONCERNS BASED ON CURRENT TRACK.
WE WILL CONTINUE TO WATCH FOR THREAT OF STRONG WINDS...BUT STRONG
LOW-LEVEL STABILITY WILL PROBABLY CONFINE ANY GUSTS 35+ MPH TO ALONG
THE WRN SLOPES OF THE GREEN MTNS...AND ACROSS THE HIGHER ELEVATIONS
OF THE NRN ADIRONDACKS AND THE GREENS. HAVE SHOWN GUSTS 35-40 MPH IN
THESE LOCALIZED AREAS IN THE CURRENT SET OF FORECAST GRIDS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 337 PM EST MONDAY...LARGE-SCALE SYSTEM WILL THEN BE IN THE PROCESS
OF CROSSING THE REGION DURING THURSDAY WITH WIDESPREAD PCPN. LATEST
MEDIUM RANGE ENSEMBLE SOLNS SUPPORT THIS MORNINGS OPERATIONAL RUNS
SHOWING PRIMARY SFC CENTER PASSING OVER OR JUST TO OUR WEST. THIS
WOULD ALLOW MILDER AIR TO CONTINUE STREAMING NORTHWARD...SUPPORTING
PRIOR REASONING FOR MAINLY AN ALL RAIN SCENARIO. SOME GUSTY WIND
POSSBL HERE AS WELL...THOUGH WITH STABILIZING INFLUENCE OF FALLING
PCPN AND CORE OF STRONGEST WINDS LIKELY ABOVE INVERSION HEIGHT
WILL DOWNPLAY THIS FOR NOW AND HIGHLIGHT ENHANCED VALUES IN
ELEVATED TERRAIN ONLY. PCPN SHOULD BEGIN TO TAPER TO SCT RAIN/SNOW
SHOWERS BY LATER IN THE DAY AND ESP BY THU NIGHT AS SYSTEM PULLS
AWAY ALONG WITH DEEPER MOISTURE.
BY FRI/FRI NT...PCPN TAKES ON A MORE OROGRAPHIC/LAKE ENHANCED
CHARACTER AS MEAN FLOW VEERS TO SOUTHWEST ALONG WITH GRADUALLY
COOLING TEMPS AS MEAN HEIGHTS/THICKNESS VALUES SLOWLY FALL
W/APPROACH OF DAMPENING POLAR TROUGH. HAVE LEANED CLOSE TO MEXMOS
TEMPS HERE...THOUGH WITH SOME SLIGHT MODIFICATIONS DUE TO EXPECTED
HIGH DEGREE OF CLOUD COVER.
THEREAFTER...SEASONABLY COLD WEATHER ALONG WITH SCT MAINLY NRN MTN
AND/OR LK EFFECT SHSN POSSBL BY SAT INTO MONDAY. BROADER VALLEYS TO
STAY ESSENTIALLY DRY DURING THESE PERIODS.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...CURRENTLY CIGS ARE GENERALLY VFR BUT WITH
MVFR AT KMPV AND KSLK. A WEAKENING TROUGH WILL BRING A CHANCE OF
LIGHT SHOWERS TO NORTHERN TAF SITS TOMORROW... IN THE FORM OF
LIGHT SNOW SHOWERS/FLURRIES EARLY MORNING AT KMSS WITH A CHANCE OF
MVFR CIGS...AND VFR SPRINKLES NEAR KBTV AND KPBG MID TO LATE
MORNING...THOUGH MOST LIKELY IN THE CPV WE WILL JUST SEE VIRGA.
AFTER 15Z KSLK COULD SEE SOME MVFR -SHSN FROM THE TAIL END OF SOME
SNOW SHOWERS OFF LAKE ONTARIO. THESE SHOWERS COULD MOVE INTO
IMPACT KRUT AND EVEN KMPV IN THE AFTERNOON...BUT WILL BE VERY
LIGHT. WINDS THROUGH THE PERIOD WILL BE GENERALLY LESS THAN 10 KT
AND FROM THE NW TONIGHT...BACKING TO SSW BY MORNING. MTNS WILL BE
OBSCURED IN CLOUDS IN THE DACKS AFTER 14Z AND POSSIBLY IN THE
GREENS AFTER 18Z.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
00Z WED THRU 00Z THU...VFR.
00Z THU THRU 00Z FRI...MVFR/IFR IN RAIN AND GUSTY WINDS/LLWS
POSSIBLE.
00Z FRI THRU 00Z SAT...VFR/MVFR IN SCATTERED SNOW SHOWERS..MAINLY
NRN MTNS.
00Z SAT THRU 00Z SUN...VFR/MVFR POSSIBLE IN LIGHT RAIN AND/OR SNOW.
&&
.CLIMATE...
BTV REMAINS WITHOUT MEASURABLE SNOWFALL SO FAR THIS SEASON. THE
RECORD LATEST DATE IS WITHIN SIGHT.
FOR BURLINGTON...ON AVERAGE THE FIRST MEASURABLE SNOW HAPPENS
NOVEMBER 6TH. HERE ARE THE 10 LATEST FIRST SNOWS FOR BURLINGTON
GOING BACK TO 1906...ALONG WITH THE SEASONAL TOTAL SNOW THAT
FOLLOWED.
SEASON TOTAL
RANK DATE SNOWFALL (INCHES)
1. 12/7/1937 45.1
2. 12/5/1915 54.4
3. 12/1/1948 40.7
4. 11/30/1918 69.6
11/30/1953 83.6
11/30/1960 51.6
7. 11/28/1913 56.5
8. 11/27/1941 57.7
9. 11/26/1982 80.5
10. 11/25/1957 94.9
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/MB
SHORT TERM...BANACOS
LONG TERM...JMG
AVIATION...AMF/WGH
CLIMATE...WFO BTV
