617
FXUS61 KBTV 152245
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
545 PM EST SUN DEC 15 2024
SYNOPSIS
A PERIOD OF ACTIVE WEATHER STARTS TONIGHT WITH THE FIRST OF SEVERAL
SYSTEMS TRACKING THROUGH THE NORTHEASTERN UNITED STATES. THE
SYSTEM TONIGHT WILL MAINLY STAY TO OUR SOUTH WITH A FEW SNOW
SHOWERS POSSIBLE ACROSS SOUTHERN VERMONT. WIDESPREAD RAINFALL IS
EXPECTED TOMORROW NIGHT INTO TUESDAY BUT SHOULD MOVE THROUGH
THE REGION QUICKLY. SEVERAL OTHER SYSTEMS WILL MOVE ACROSS THE
NORTH COUNTRY LATE THIS WEEK AND NEXT WEEKEND WITH ADDITIONAL
RAIN AND SNOW POSSIBLE.
NEAR TERM /THROUGH MONDAY NIGHT/
AS OF 541 PM EST SUNDAY...LIGHT RADAR RETURNS ARE MOVING INTO
SOUTHWESTERN ST LAWRENCE COUNTY THIS HOUR, LIKELY VIRGA, AND
WILL CONTINUE TO PROGRESS NORTHEASTWARD THROUGH THE OVERNIGHT
HOURS. AS ANTICIPATED, THE FORCING WITH THIS WAVE IS LIGHT, BUT
0.01 OR SO OF AN INCH OF QPF CANNOT BE RULED OUT. OTHERWISE, THE
NEK IS COOLING FASTER THAN ANTICIPATED, SO THE THERMAL CURVES
IN THE FORECAST WERE ADJUSTED TO BETTER MATCH OBSERVATION
TRENDS.
PREVIOUS DISCUSSION...UPPER LEVEL LOW PRESSURE IS EXPECTED TO
TRACK EASTWARD TONIGHT FROM NORTHWESTERN PENNSYLVANIA TO THE
HUDSON VALLEY OF NEW YORK, BRINGING INCREASING CLOUDS AND SOME
20-50% CHANCE OF PRECIPITATION IN WESTERN AND SOUTHERN AREAS OF
THE FORECAST AREA. PRECIPITATION CHANCES WILL BE LIMITED FOR
MOST AS THE SYSTEM RUNS UP AGAINST UPPER RIDGING AND DRY AIR.
SOUTHERLY RETURN FLOW BEHIND SURFACE PRESSURE IN THE ATLANTIC
OCEAN PLUS THE INCREASED CLOUDS WILL KEEP TEMPERATURES
RELATIVELY MILD TONIGHT WITH LOWS IN THE MID TEENS TO 20S. THESE
TEMPERATURES ARE EXPECTED TO KEEP ANY PRECIPITATION THAT FALLS
AS LIGHT SNOW, BUT OVERRUNNING MILDER AIR MAY CAUSE SOME
ISOLATED AREAS OF LIGHT FREEZING RAIN OR FREEZING DRIZZLE. WINDS
COULD BECOME QUITE BLUSTERY ON LAKE CHAMPLAIN AND ON
MOUNTAINTOPS OVERNIGHT WITH GUSTS 20-40 KNOTS.
TOMORROW, THE UPPER LOW WILL WEAKEN ACROSS SOUTHERN NEW ENGLAND
AFTER RUNNING INTO THE RIDGING/HIGH PRESSURE, AND ATTENTION TURNS TO
A VERTICALLY STACKED LOW PRESSURE SYSTEM APPROACHING FROM ONTARIO.
GRADIENT WILL TIGHTEN BETWEEN ITS FRONTAL BOUNDARY AND THE ATLANTIC
HIGH TO THE EAST, INCREASING SOUTHERLY WINDS AND ADVECTING IN MILDER
AIR. WINDS COULD BE GUSTING AS HIGH AS 30+ KNOTS ON LAKE CHAMPLAIN
AND ALONG MOUNTAINTOPS AS A LOW LEVEL JET CREEPS INTO THE AREA FROM
THE SOUTHWEST. HIGHS WILL REACH INTO THE UPPER 30S TO LOWER 40S,
TURNING ANY LINGERING PRECIPITATION (20-40% CHANCES) TO LIGHT RAIN
OR EVEN DRIZZLE.
STEADIER PRECIPITATION IS EXPECTED TO ARRIVE MONDAY NIGHT,
INCREASING PRECIP CHANCES 70-100%. TEMPERATURES WILL NON-DIURNALLY
RISE THROUGHOUT THE NIGHT, ALLOW FOR LOWS AS HIGH AS THE MID 30S TO
LOWER 40S AND KEEPING MOST PRECIP RAIN. THERE IS THE POTENTIAL FOR
SOME MIXED WINTRY PRECIP IN HIGHER ELEVATIONS AND COLDER SPOTS WHERE
COLDER SURFACE TEMPERATURES COULD CREATE QUITE THE INVERSION. WINDS
WILL GUST THE HIGHEST MONDAY NIGHT WITH A 60-65 KNOT LOW LEVEL JET
AT THE 850MB LAYER. MUCH COULD DEPEND ON HOW MUCH MIXING OCCURS AS
SOME MODEL SOUNDINGS, PARTICULARLY THOSE EAST OF THE GREENS, APPEAR
SATURATED. MOUNTAINTOPS, THE NORTHWESTERN SLOPES OF THE ADIRONDACKS,
AND THE CHAMPLAIN VALLEY COULD HAVE SOME OF THE HIGHEST SOUTH-
SOUTHEASTERLY WIND GUSTS 20-40 KNOTS, LOCALLY HIGHER AT SUMMITS.
TOTAL RAINFALL AMOUNTS WILL BE ABOUT 0.10-0.20" IN TERRAIN-SHADOWED
AREAS TO AS HIGH AS 0.20-0.60" ELSEWHERE.
SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/
AS OF 331 PM EST SUNDAY...MID/UPPER LVL DRY SLOT WL BE TRAVERSING OUR
CWA ON TUES AM, AS ANY LINGERING PRECIP QUICKLY ENDS. AS COOLER AIR
ARRIVES AT 850MB UNDER MODEST CAA ON WESTERLY WINDS, LAPSE RATES WL
STEEPEN AS BL TEMPS WARM INTO THE UPPER 30S TO MID/UPPER 40S. THESE
STEEPENING SFC TO 850MB LAPSE RATES, COMBINED WITH CORE OF 925MB TO
850MB WINDS OF 30 TO 45 KNOTS, WL SUPPORT LOCALIZED WIND GUSTS 35 TO
45 MPH, ESPECIALLY NORTHERN DACKS ALONG THE ROUTE 11 CORRIDOR AND
PARTS OF THE SLV/EASTERN DACKS. ELSEWHERE, GUSTS IN THE 25 TO 40 MPH
RANGE IS LIKELY, WHICH SHOULD BE ENOUGH TO HELP MIX LLVL COLD AIR
NEAR THE SFC EAST OF THE GREENS AND WARM TEMPS INTO THE 40S ON TUES.
A FEW LIGHT RAIN/MTN SNOW SHOWERS ARE POSSIBLE DURING THE AFTN, BUT
QPF/SNOWFALL WL BE MINIMAL GIVEN THE LACK OF DEEP LAYER
MOISTURE/FORCING AND VERY LIMITED LAKE INDUCED INSTABILITY. TUES
NIGHT IS QUIET WITH GRADIENT FLOW PREVAILING AS THE CENTER OF HIGH
PRES IS TO OUR SOUTH, THIS WL RESULT IN MIXED BL CONDITIONS AND KEEP
TEMPS ON THE WARMER SIDE OF GUIDANCE FOR LOWS ON TUES NIGHT. COOLEST
VALUES WL BE SUMMITS AS PROGGED 850MB TEMPS DROP BTWN -4C AND -6C,
SUPPORTING MID 20S TO MID 30S MOST LOCATIONS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS OF 331 PM EST SUNDAY...CONFIDENCE CONTS TO GROW FOR LIGHT PRECIP
EVENT LATE WEDS INTO WEDS NIGHT, FOLLOWED BY A RETURN OF SOME COOLER
AIR FOR LATE WEEK INTO NEXT WEEKEND. THE LARGE SCALE SYNOPTIC
PATTERN CONTS TO INDICATE FAST CONFLUENT FLOW ALOFT PREVAILING FOR
MIDWEEK, BEFORE MID/UPPER LVL TROF DEEPENS TOWARD NEXT WEEKEND. A
WEAK 1016MB SFC LOW PRES LOCATED OVER THE SOUTHERN OHIO VALLEY AT
12Z WEDS WL QUICKLY TRACK NORTHEAST AND BE LOCATED EAST OF MAINE BY
12Z THURS. UPPER LEVEL JET ANALYSIS SHOWS OUR CWA BRIEFLY UNDER
RIGHT REAR QUAD OF 140 TO 160 KNOT JET AT 250MB ON WEDS EVENING,
WHICH WL PROMOTE FAVORABLE SYNOPTIC SCALE LIFT ACRS OUR CWA. IN
ADDITION, DID NOTE A QUICKLY MOVING AREA OF ENHANCED 700MB FGEN
FORCING LIFTING FROM SW TO NE ACRS OUR CWA ON WEDS EVENING, WITH
STRONGEST FORCING OVER OUR CENTRAL/SOUTHERN CWA, WHERE THE THERMAL
GRADIENT IS LOCATED. THIS SYNOPTIC SCALE ASCENT, COMBINED WITH
MOISTURE ADVECTION, AS PWS CLIMB BTWN 0.70 AND 0.90" SUPPORTS A
PERIOD OF LIGHT PRECIP WEDS INTO WEDS NIGHT. GIVEN THE FAST 700 TO
500MB FLOW OF 50 TO 80 KNOTS, I HAVE POPS QUICKLY EXPANDING TO
LIKELY/CATEGORICAL BY 21Z WEDS, WITH HIGHEST VALUES ACRS OUR
CENTRAL/SOUTHERN CWA. INITIALLY SOUNDINGS AT BTV SHOW BL TEMPS NEAR
4C, WHICH WOULD SUPPORT A MIX OF RAIN/SNOW, BUT AS NIGHT-TIME
ARRIVES AND FREEZING LEVELS LOWER, FEEL ANY MIX TURNS TO MOSTLY A
WET SNOW BY EVENING. INITIAL THOUGHTS WOULD BE A LOW END ADVISORY
MAYBE EVENTUALLY NEEDED FOR SOUTHERN VT MTNS FOR 3 TO 5 INCHES OF
SNOW, WITH AMOUNTS A DUSTING TO 4 ELSEWHERE. WE WL CONTINUE TO FINE
TUNE THERMAL PROFILES AND ASSOCIATED PTYPE AS THE EVENT IS BETTER
SAMPLED BY HIGH RES DATA. HIGHS MOSTLY IN THE MID 30S TO NEAR 40F
WEDS, DROP BACK INTO THE MID 20S TO LOWER 30S BY 12Z THURS. A PERIOD
OF UPSLOPE SNOW SHOWERS WL BE LIKELY ON THURS UNDER MODERATELY
STRONG LLVL CAA. GIVEN THE QUICK MOVEMENT OF SYSTEM, EXPECT DEEPER
MOISTURE WL DEPART QUICKLY ON THURS, RESULTING IN SNOW SHOWER
ACTIVITY QUICKLY DECREASING BY 00Z FRIDAY. SEVERAL INCHES OF FLUFFY
IS LIKELY IN THE NORTHERN DACKS AND NORTHERN GREENS FROM MT
MANSFIELD TO JAY PEAK ON THURS.
FOR LATE WEEK INTO NEXT WEEKEND MID/UPPER LVL TROF DEEPENS ACRS THE
GREAT LAKES INTO THE NE CONUS, BUT STRENGTH OF CAA AND PLACEMENT OF
BUILDING SFC HIGH PRES HAS LOW PREDICTABILITY GIVEN THE LARGE SPREAD
IN GUIDANCE. HAVE CONTINUED WITH CHC (30-40%) MOSTLY IN THE MTNS FOR
LATE WEEK INTO NEXT WEEKEND UNDER FAVORABLE UPSLOPE FLOW AND LLVL
CAA. DID NOTE THE 12Z EURO IS PRETTY COLD FOR NEXT WEEKEND WITH
1000-500MB THICKNESS VALUES <500 DAM AND PROGGED 925MB IN THE - 24C
TO -28C RANGE, WHILE THE GFS/CMC SHOW THE CORE OF THE COLDEST AIR
PASSING JUST TO OUR NORTH. IN ADDITION, EURO COULD HAVE SOME WIND AS
THE SFC HIGH PRES IS INITIALLY CENTERED OVER THE GREAT LAKES,
RESULTING IN NORTH/NORTHWEST FLOW ACRS OUR CWA. PLENTY OF DETAILS TO
BE DETERMINED WITH REGARDS TO COLD AIR, SO FOR NOW HAVE TRENDED
TOWARD THE COOLER NBM 25TH PERCENTILE FOR HIGHS/LOWS FRIDAY INTO
SUNDAY.
AVIATION /00Z MONDAY THROUGH FRIDAY/
THROUGH 18Z MONDAY...HIGH CLOUDS CONTINUE TO OVERSPREAD THE
FORECAST AREA THIS MORNING AS WINDS BEGIN TO PICK UP.
SOUTH TO SOUTHWESTERLY WINDS SUSTAINED 5-15 KNOTS EXPECTED OVER
THE NEXT SEVERAL HOURS WITH GUSTS AT BTV 15-25 KNOTS DUE TO
SOUTHERLY CHANNELING IN THE CHAMPLAIN VALLEY. VFR CONDITIONS
LIKELY FOR THE NEXT 6 HOURS AND EXPECTED THROUGH AT LEAST 05Z
MONDAY. MVFR LEVEL CEILINGS WILL BEGIN TO ARRIVE ACROSS THE
FORECAST AREA AROUND 05Z-10Z MONDAY, THOUGH THESE LOWER CEILINGS
MAY HOLD OFF IN SOME AREAS (E.G. EFK) UNTIL AROUND 15Z MONDAY.
LOW PROBABILITIES 20-40% OF LIGHT SNOW OR SNOW SHOWERS EXPECTED
03Z-18Z MONDAY, EXACT TIMING DEPENDING ON THE INDIVIDUAL TAF
SITES AS A LOW PRESSURE MOVES FROM WEST TO EAST JUST TO THE
SOUTH OF US. MOST LIKELY LOCATION TO SEE SNOW WILL BE RUT, AS
IT IS FARTHEST SOUTH AND CLOSEST TO THE LOW. PRECISE
VISIBILITIES NOT YET DETERMINED, BUT THIS PRECIP SHOULD BE LIGHT
WITH VIS 5+ MILES. AS THE SYSTEM APPROACHES, WE MAY GET MORE
DETAILS ON DECREASING VISIBILITIES IN SNOW SHOWERS. WINDS
SHOULD CONTINUE THROUGHOUT THE 24 HOUR PERIOD OUT OF THE SOUTH-
SOUTHEAST FOR MOST SITES. LLWS WILL ALSO BE A CONCERN, MAINLY
FROM 05Z-08Z ONWARD IN NORTHERN NEW YORK.
OUTLOOK...
MONDAY NIGHT: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. WINDY WITH
GUSTS TO 30 KT. DEFINITE RA, CHANCE DZ.
TUESDAY: MAINLY MVFR, WITH AREAS VFR POSSIBLE. WINDY WITH GUSTS
TO 30 KT. CHANCE RA.
TUESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. NO SIG WX.
WEDNESDAY: MAINLY MVFR, WITH AREAS VFR POSSIBLE. CHANCE SHRA,
SLIGHT CHANCE SHSN.
WEDNESDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. DEFINITE SHRA,
LIKELY SHSN.
THURSDAY: MAINLY MVFR, WITH AREAS VFR POSSIBLE. CHANCE SHSN.
THURSDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT
CHANCE SHSN.
FRIDAY: VFR. SLIGHT CHANCE SHSN.
MARINE
SOUTH WINDS 15 TO 30 KNOTS ARE ANTICIPATED TONIGHT ON LAKE
CHAMPLAIN WITH GUSTS POTENTIALLY UP TO 40 KNOTS ON THE BROAD
LAKE. WAVES WILL BE ANYWHERE FROM 1 TO 5 FEET. WINDS SHOULD
DIMINISH SLIGHTLY LATE TONIGHT THEN INCREASE AGAIN TOMORROW.
EQUIPMENT
PLATTSBURGH ASOS IS MISSING VISIBILITY IN REPORTS AND IS
AWAITING A PART TO FIX THIS ISSUE, WHICH IS CURRENTLY
UNAVAILABLE UNTIL FEBRUARY 1.
BTV WATCHES/WARNINGS/ADVISORIES
VT...NONE.
NY...NONE.
SYNOPSIS...STORM
NEAR TERM...BOYD/STORM
SHORT TERM...TABER
LONG TERM...TABER
AVIATION...STORM
MARINE...TEAM BTV
EQUIPMENT...TEAM BTV
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