539
FXUS61 KBTV 271133
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
733 AM EDT THU AUG 27 2026
WHAT HAS CHANGED
AS OF 230 AM EDT THURSDAY...
STRONG TO POSSIBLY SEVERE THUNDERSTORM CHANCES THIS AFTERNOON
HAVE INCREASED ACROSS SOUTHWESTERN VERMONT. A SLIGHT RISK HAS
BEEN INTRODUCED TO ESSEX COUNTY, NY AND ADDISON AND RUTLAND
COUNTIES IN VERMONT FOR THIS AFTERNOON. THERE IS ALSO INCREASING
CONFIDENCE IN POTENTIAL LOCALIZED FLASH FLOODING ACROSS RUTLAND
COUNTY AND SOUTHERN VERMONT THIS AFTERNOON/EVENING FROM
POTENTIAL TRAINING THUNDERSTORMS.
KEY MESSAGES
AS OF 230 AM EDT THURSDAY...
1. THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND EVENING, WITH
GREATER CHANCES IN VERMONT AND PARTICULARLY IN OUR SOUTHERN AREAS.
SOME STORMS WILL BE CAPABLE OF STRONG WINDS, SMALL HAIL, AND HEAVY
RAIN.
2. SOME LINGERING SHOWERS WILL BE POSSIBLE EARLY ON FRIDAY,
BEFORE HIGH PRESSURE, AND DRYING CONDITIONS LEAD TO A QUIET WEEKEND.
3. AN ACTIVE WEATHER PATTERN WILL PREVAIL EARLY NEXT WEEK.
DISCUSSION
AS OF 230 AM EDT THURSDAY...
KEY MESSAGE 1: CONFIDENCE IN AFTERNOON SHOWERS AND THUNDERSTORMS, SOME
OF WHICH COULD BE STRONG TO SEVERE, REMAINS ON TRACK. SPC HAS NUDGED
THE SLIGHT RISK (LEVEL 2 OUT OF 5) FOR SEVERE THUNDERSTORMS
NORTHEAST TO INCLUDE ESSEX COUNTY NY, AND RUTLAND AND ADDISON
COUNTIES IN VERMONT FOR THIS AFTERNOON. THE AREAS INCLUDED IN THE
PREVIOUS MARGINAL RISK FOR SEVERE THUNDERSTORMS FOR TODAY HAS
REMAINED UNCHANGED. SYNOPTICALLY, AN OCCLUDING SURFACE LOW WITH
ASSOCIATED WARM FRONT OVER WESTERN NEW YORK THIS MORNING WILL LIFT
THROUGH THE REGION EARLY TO MID THIS AFTERNOON. SHOWERS WILL BE
POSSIBLE ALONG THE WARM FRONT AS EARLY AS MID TO LATE THIS MORNING
ALONG THE SOUTHERN GREENS AND ST. LAWRENCE VALLEY. WATER VAPOR
DEPICTIONS UPSTREAM INTO WESTERN NEW YORK AND PENNSYLVANIA SHOW
DECENT DRY AIR AHEAD OF A STOUT BOUNDARY OF SHOWERS IN WESTERN
PENNSYLVANIA. THIS CLEARING WILL HELP OUR REGION DESTABILIZE THIS
AFTERNOON AS MLCAPE SURGES TO 1000-1500J/KG, WITH SOME POCKETS OF
1500-2000J/KG ACROSS THE EASTERN ADIRONDACKS AND CHAMPLAIN VALLEY.
WHILE THERE WILL BE GOOD INSTABILITY IN THE WARM SECTOR THIS
AFTERNOON AS TEMPERATURES CLIMB TO NEAR 80, WITH DEWPOINTS IN THE
LOW 60S, DEEP LAYER SHEAR WILL BE LESS THAN IDEAL FOR STRONG
ORGANIZED STORMS. 20-30KNOTS OF BULK 0-6KM SHEAR IS EXPECTED THIS
AFTERNOON, WHICH IS ON THE LOWER SIDE OF SUFFICIENT SHEAR FOR SEVERE
STORMS; THE BETTER SHEAR WILL BE WELL TO OUR EAST NEAR THE MAIN COLD
FRONT. REGARDLESS, NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS,
WITH SOME ISOLATED STORMS BECOMING STRONG TO SEVERE, ARE
ANTICIPATED, MAINLY IN THE 3-8 PM TIMEFRAME, MOVING WEST TO EAST.
THE MAIN RISKS ASSOCIATED WITH OUR STORM POTENTIAL THIS AFTERNOON
WILL BE GUSTY WINDS, ISOLATED SMALL HAIL. ALTHOUGH SHEAR IS ON THE
LOWER BOUNDS FOR FAVORABLE SEVERE CONDITIONS, STORMS MODES LOOK TO
FAVOR SOME MINI BOWING SEGMENTS AND MULTICELLS WHICH CAN DRIVE
STRONG COLD POOLS AND THUS ISOLATED GUSTY WINDS. GIVEN DECENT MID
LEVEL LAPSE RATES TO 6-7C/KM, AND GOOD ELEVATED INSTABILITY IN THE
HAIL GROWTH ZONE, SMALL HAIL WILL BE POSSIBLE WITHIN STRONGER
UPDRAFTS. WHILE THE PROBABILITIES ARE LOW, THERE IS A LOW RISK FOR
SOME ISOLATED ROTATION WITHIN STORMS THIS AFTERNOON. AS THE WARM
FRONT LIFTS THROUGH THE REGION THIS AFTERNOON, WINDS IN THE LOW
LEVEL WILL TURN MORE SOUTHEASTERLY, AND PAIRED WITH PREVAILING
SOUTHWESTERLY FLOW ALOFT, VEERING FLOW COULD LEAD TO AN INCREASE IN
LOW LEVEL SPIN. 0-1KM SRH WILL BE LOW AROUND 100-150 M2/S2, THOUGH
COULD BE ENOUGH TO LEAD TO SOME ISOLATED ROTATION, ESPECIALLY SHOULD
ANY STORMS DEVELOP ALONG THE WARM FRONT, AND OUT AHEAD OF THE MAIN
BOUNDARY THIS AFTERNOON. ALL HAZARDS WILL BE POSSIBLE THIS
AFTERNOON, THOUGH THE MAIN CONCERNS WILL BE WINDS IN THE FORM OF
STRAIGHT-LINED WINDS. AT THIS TIME, A GREATER RISK/MORE COVERAGE OF
STRONGER STORMS IS FAVORED SOUTH OF OUR REGION PER CONSENSUS OF BOTH
THE PHYSICALLY-BASED AND MACHINE LEARNING MODEL GUIDANCE.
HEAVY RAIN WILL ALSO BE A CONCERN WITH WPC PLACING THE ENTIRE AREA
IN A MARGINAL RISK (LEVEL 1 OUT OF 4) FOR A 5% CHANCE OF EXCEEDING
FLASH FLOOD GUIDANCE WITHIN 25 MILES OF AN AREA. PWATS WILL BE
AROUND 1.5-1.7 INCHES, THE 85TH PERCENTILE FOR THIS TIME OF YEAR,
WITH MODEST WARM LAYER CLOUD DEPTHS AROUND 10,000 FT. WHILE THESE DO
NOT FAVOR FLASH FLOOD POTENTIAL, THE FLASH FLOOD RISK TODAY WILL BE
DRIVEN BY CONDITIONAL TRAINING STORMS. CELLS MAY BECOME ALIGNED TO
THE BACKGROUND FLOW ACROSS SOUTHERN VERMONT AND LEAD TO A LOCALIZED
CHANCE FOR FLASH FLOODING. PROBABILITIES FOR 2" OF RAIN THROUGH 8 AM
FRIDAY HIGHLIGHT WESTERN RUTLAND COUNTY IN AREAS LIKE FAIR HAVEN,
AND RUTLAND ITSELF IN A 20% PROBABILITY. HREF PROBABILITIES DENOTE A
10% CHANCE FOR THIS AREA TO SEE UPWARDS OF 3". THESE HIGH RAINFALL
AMOUNTS WILL BE HIGHLY CONDITIONAL ON TRAINING THUNDERSTORMS AND
DOES STILL APPEAR UNLIKELY, THOUGH THERE IS SOME BETTER CONFIDENCE
THAN PREVIOUS FORECASTS FOR THIS AREA TO SEE SOME LOCALIZED FLASH
FLOODING. HAVE INCREASED RAINFALL AMOUNTS TO REFLECT THIS IN
SOUTHERN VERMONT TO AROUND AN INCH, TO LOCALLY 1-2" SHOULD A FEW
THUNDERSTORMS MOVE OVER THE SAME AREAS. INTERESTS IN SOUTHERN
VERMONT, SHOULD PAY CLOSE ATTENTION TO OUR FORECAST AND RADAR TRENDS
THIS AFTERNOON, AS CONDITIONS COULD CHANGE QUICKLY.
KEY MESSAGE 2: A COLD FRONT WILL GRADUALLY MOVE FROM WEST TO EAST EARLY
FRIDAY SPURRING SOME LINGERING SHOWERS ACROSS VERMONT. GIVEN THE
TIMING OF THE FRONTAL PASSAGE, INSTABILITY WILL BE LOW, SO
ANTICIPATING JUST SOME LIGHT SHOWERS. THOUGH SHOULD THE FRONT SLOW
AS IT NEARS THE VT/NH BORDER, SOME ISOLATED RUMBLES OF THUNDER MAY
BE POSSIBLE. SHOWERS WILL TAPER OFF FRIDAY EARLY TO MID AFTERNOON,
WITH CLEARING SKIES FROM WEST TO EAST. TEMPERATURES WILL BE A FEW
DEGREES COOLER THAN THURSDAY IN THE LOW TO MID 70S, WITH PERHAPS
SOME UPPER 70S, SHOULD THE COLD FRONT SLOW AS IT MOVES EAST ALLOWING
FOR MORE DIURNAL HEATING IN THE DEEPER VALLEYS. LOWS FRIDAY NIGHT
WILL COOL OFF UNDER STRONG RADIATIONAL COOLING INTO THE UPPER 40S
FOR MOST LOCATIONS, OUTSIDE OF AREAS NEAR THE ST. LAWRENCE RIVER AND
LAKE CHAMPLAIN WHERE LOW 50S ARE EXPECTED. SOME POCKET LOW 40S, TO
NEAR 40 WILL BE POSSIBLE IN THE MORE SHELTERED LOCATIONS OF THE
ADIRONDACKS. WITH THE STRONG RADIATIONAL COOLING, VALLEY FOG
FOLLOWING THE RECENT RAINS WILL BE POSSIBLE. SATURDAY LOOKS TO BE
PLEASANT WITH TEMPERATURES IN THE MID TO UPPER 70S UNDER HIGH
PRESSURE. SOME LIGHT SOUTHWEST CHANNELED FLOW IN THE ST. LAWRENCE
VALLEY WILL BE POSSIBLE, THOUGH BY AND LARGE WINDS WILL REMAIN LIGHT
UNDER 10 MPH. CLOUDS WILL INCREASE SATURDAY NIGHT.
KEY MESSAGE 3: SUNDAY INTO MONDAY, A VIGOROUS VORT WILL DIG TOWARDS THE
BASE OF A LONGWAVE TROUGH PATTERN POSITIONED IN QUEBEC PROVINCE.
MEANWHILE, A STRONG UPPER HIGH IN THE DESERT SOUTHWEST WILL WEAKEN
AND SHIFT EAST. THIS WILL OPEN UP A STREAM OF TROPICAL PACIFIC AIR
THAT TRACKS ALONG THE INTERNATIONAL BORDER. THIS WILL RESULT IN
ACCELERATING FLOW OVER OUR REGION WITH SYSTEMS. SURFACE HIGH
PRESSURE WILL BUILD ACROSS QUEBEC PROVINCE ONCE THE VIGOROUS VORT
PUSHES EAST. THE NORTHEASTERLY FLOW FROM THAT HIGH AND THE ATTEMPT
FOR WARM, HUMID AIR EKING CLOSER TO US WILL PLACE US NEAR ALONG A
STATIONARY MOISTURE GRADIENT THROUGH AT LEAST NEXT WEDNESDAY.
THERE'S PLENTY OF SPREAD, BUT PERUSING VARIOUS ENSEMBLE
PROBABILITIES OF GREATER THAN 0.5" SHOWS SOME POTENTIAL THROUGHOUT
MONDAY THROUGH THURSDAY. TAKING IN A VIEW OF A 72-HOUR TIME FRAME,
NBM PROBABILITIES FOR AT LEAST 2" IN THE MONDAY-THURSDAY TIME FRAME
IS ABOUT 10-15% AND 30-40% FOR AN INCH OF RAIN. SO A PERIOD OF ABOVE
NORMAL PRECIPITATION APPEARS LIKELY HEADING INTO NEXT WEEK. WILL
FINE TUNE THE TIMING AS WE DRAW A LITTLE CLOSER. TEMPERATURES WILL
BE RUN RELATIVELY CLOSE TO SEASONAL NORMS (MID TO UPPER 70S AT DAY,
50S AT NIGHT, BUT 40S FOR THE ADIRONDACK REGIONAL AIRPORT).
AVIATION /12Z THURSDAY THROUGH MONDAY/
THROUGH 12Z FRIDAY...CONDITIONS ARE MAINLY VFR. DESPITE VADS
INDICATING MODEL FORECAST WINDS OFF THE SURFACE LIKELY VERIFIED
WITH KCXX NOTING 20 KNOTS AT 1000 FEET, KMPV STILL MANAGED TO
OBSERVE PREVAILING LIFR CEILINGS AND VISIBILITY DUE TO FOG.
UPSTREAM, SCATTERED SHOWERS ARE APPROACHING THE AREA. IT'S
POSSIBLE THEY PRODUCE RAIN AT KMPV/KRUT/KEFK AS THEY LIFT
NORTHEAST. THE PRIMARY BATCH OF SHOWERS AND STORMS WILL COME
FROM A BOUNDARY ON THE EASTERN HALF OF LAKE ONTARIO. AHEAD OF
THE FEATURE, SOUTH WINDS WILL INCREASE TO 8-14 KNOTS SUSTAINED
WITH GUSTS 17-24 KNOTS, WITH THE HIGHEST SPEEDS AT
KBTV/KPBG/KMSS. STORMS WILL BE MORE HIT OR MISS ACROSS NORTHERN
NEW YORK FROM ABOUT 16Z-21Z, BUT ACTIVITY APPEARS MORE LIKELY TO
COALESCE NEAR KRUT AND NOTED PREVAILING TSRA FROM 23Z-04Z AS
THE BOUNDARY APPEARS TO BRIEFLY STALL OVER THAT REGION. HEAVY
RAIN AND GUSTY WINDS COULD OCCUR IN THUNDERSTORMS, AND WILL BE
MOST LIKELY AT KRUT. WINDS WILL TREND LIGHT AND VARIABLE FOR
MOST, AND AS CLOUDS CLEAR, FOG WILL LIKELY DEVELOP AS EARLY AS
02-04Z.
OUTLOOK...
FRIDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SCATTERED SHRA.
FRIDAY NIGHT: VFR. NO SIG WX.
SATURDAY: VFR. NO SIG WX.
SATURDAY NIGHT: VFR. NO SIG WX.
SUNDAY: VFR. CHANCE SHRA.
SUNDAY NIGHT: MAINLY VFR, WITH AREAS MVFR POSSIBLE. CHANCE SHRA.
MONDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT CHANCE SHRA.
MARINE
AS OF 230 AM EDT THURSDAY...
A LAKE WIND ADVISORY IS IN EFFECT FOR THE BROAD AND NORTHERN WATERS
OF LAKE CHAMPLAIN UNTIL 8 PM TODAY. SOUTH WINDS AHEAD AN APPROACHING
FRONTAL SYSTEM WILL LEAD TO INCREASING CHANNELED WINDS ON LAKE
CHAMPLAIN BY LATE THIS MORNING ENHANCING GUSTS AND WAVE
CONDITIONS. WINDS AND GUSTS ON THE LAKE WILL INCREASE TO 15 TO
25 KNOTS THROUGH THIS AFTERNOON. WAVES WILL BE GENERALLY 1 TO 3
FT. GUSTS WILL WEAKEN BACK TO AROUND 10 TO 15 KNOTS AFTER SUNSET
THIS EVENING WITH THE PASSAGE OF A BOUNDARY. THUNDERSTORMS WILL
BE POSSIBLE THIS AFTERNOON PRIMARILY BETWEEN 2-6 PM, WHICH CAN
FURTHER ENHANCE GUSTY WINDS. WITHIN ANY THUNDERSTORMS, SMALL
HAIL, AND HEAVY RAIN WILL ALSO BE POSSIBLE.
BTV WATCHES/WARNINGS/ADVISORIES
VT...NONE.
NY...NONE.
WHAT HAS CHANGED...DANZIG
DISCUSSION...HAYNES/DANZIG
AVIATION...HAYNES
MARINE...DANZIG
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