160
FXUS61 KBTV 181756
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
156 PM EDT SAT JUL 18 2026
WHAT HAS CHANGED
AS OF 1050 AM EDT SATURDAY...
WE'VE BACKED OFF BOTH TEMPERATURES AND SMOKE FOR TODAY BASED ON
OBSERVATIONS THIS MORNING. RELATEDLY, WITH A LOT MORE COVERAGE
OF LIGHT RAIN MOVING ACROSS THE REGION THROUGH MIDDAY, HAVE
INCREASED RAIN CHANCES AND REDUCED THUNDERSTORM CHANCES. A
SEVERE WIND THREAT CONTINUES FOR LATE THIS AFTERNOON, BUT THE
AREAL EXTENT LOOKS FAIRLY LIMITED AT THIS TIME. OUR SOUTHERNMOST
PORTIONS OF VERMONT AND SOUTHWESTERN ST. LAWRENCE COUNTY ARE
MOST FAVORED AS AREAS THAT GET INTO SOME MODEST INSTABILITY. NEAR
SURFACE SMOKE WILL INCREASE TO NOTICEABLE CONCENTRATIONS, BUT
DELAYED INTO THIS AFTERNOON AND AFFECT PRIMARILY NORTHERN NEW
YORK, AND PERHAPS SOUTHERN PORTIONS OF VERMONT AND HIGHER
ELEVATIONS.
KEY MESSAGES
AS OF 232 AM EDT SATURDAY...
1. THUNDERSTORMS AND HEAVY RAIN THIS AFTERNOON AND EVENING.
2. SEASONABLY COOL WEATHER AND INTERVALS OF WILDFIRE SMOKE
EXPECTED OVER THE NEXT FEW DAYS.
3. FRONTAL PASSAGES BRING CHANCES FOR SHOWERS AND THUNDERSTORMS
TUESDAY NIGHT INTO WEDNESDAY BEFORE HIGH PRESSURE DOMINATES OUR
WEATHER ON THURSDAY AND FRIDAY.
DISCUSSION
AS OF 232 AM EDT SATURDAY...
KEY MESSAGE 1: AN ANOMALOUSLY STRONG LOW FOR THE TIME OF YEAR
(~995 MB) WILL TRACK EASTWARD FROM ONTARIO THROUGH SOUTHERN
QUEBEC TODAY AND TONIGHT. SHOWERS WILL BE MORE WIDESPREAD CLOSE
TO THE INTERNATIONAL BORDER AS THE WARM FRONT AND CENTER OF THE
LOW WILL BE CLOSER. A POWERFUL COLD FRONT WILL COME THROUGH IN
THE AFTERNOON AND EVENING, BRINGING A ROUND OF SHOWERS AND
STORMS. THE AIRMASS AHEAD OF THE SYSTEM WILL BE RELATIVELY COOL
AND NOT CONDUCIVE TO HIGH INSTABILITY. PEAK MEAN HREF SBCAPE
VALUES ARE AROUND 500-750 J DURING THIS TIME FRAME AND EARLIER
ROUNDS OF SHOWERS/CLOUDS COULD PREVENT ENOUGH HEATING TO REACH
THESE VALUES. HOWEVER, DUE TO THE STRENGTH OF THE LOW, THERE
WILL BE STRONG SHEAR AND DYNAMICS. 0-6 KM SHEAR IS FORECAST TO
BE IN THE 40-50 KT RANGE. ONE THING LACKING WILL BE A
SIGNIFICANT SURFACE WIND SHIFT/CONVERGENCE WITH THE FRONT, WITH
SOUTHWESTERLY SYNOPTIC FLOW EXPECTED BEHIND THE FRONT UNTIL THE
CENTER OF THE SURFACE LOW PUSHES EAST. HEIGHT FALLS WILL BE
QUITE SIGNIFICANT THOUGH. THE MAIN THREAT FROM THE STORMS IS BY
FAR THE DAMAGING WINDS, BUT THERE IS A LARGE AMOUNT OF HELICITY
WHERE SOME LOW LEVEL ROTATION WILL BE POSSIBLE. BASED ON THIS
INFORMATION, THE SPC CONTINUED THE REGION IN A SPLIT BETWEEN A
SLIGHT AND MARGINAL RISK. THESE STORMS WILL CONTAIN HEAVY RAIN,
BUT WITH STRONG BACKGROUND FLOW, THE STORMS WILL MOVE QUICKLY
AND MINIMIZE THE FLOODING THREAT. THERE ALSO DOES NOT LOOK TO BE
A STALLED AXIS OF RAIN ALONG THE WARM FRONT ON THE FRONT SIDE
THAT OFTEN OCCURS IN THESE SETUPS. HOWEVER, THE THREAT FOR
FLOODING CANNOT BE COMPLETELY RULED OUT IF AREAS SEE MULTIPLE
ROUNDS OF HEAVY RAIN, WITH THE GREATEST THREAT OF THAT BEING
ALONG THE INTERNATIONAL BORDER. IN SUMMARY, IT IS A CONDITIONAL
SEVERE THREAT WHERE LITTLE TO NO DEVELOPMENT COULD HAPPEN, BUT
IF JUST ENOUGH SOLAR HEATING DOES OCCUR, THERE COULD BE SEVERAL
STRONG AND SEVERE STORMS THIS AFTERNOON AND EVENING.
KEY MESSAGE 2: HIGHS LOOK TO BE IN THE 70S TO MID 80S OVER THE
NEXT FEW DAYS, WITH SLIGHTLY COOLER CONDITIONS ON SUNDAY. LOWS
WILL GENERALLY BE IN THE 50S AND DEW POINTS WILL BE RELATIVELY
LOW. THE WILDFIRE SMOKE MAKES A RETURN FOR TODAY AS FLOW BECOMES
WESTERLY TO SOUTHWESTERLY, BRINGING THE SMOKE THAT IS CURRENTLY
OVER THE MIDWEST AND GREAT LAKES INTO THE REGION. THANKFULLY,
BEHIND THE COLD FRONT ON SATURDAY, WINDS EVENTUALLY BECOME
NORTHWESTERLY AND PUSH THE SMOKE BACK TO THE SOUTH. THE SOURCE
OF THE SMOKE IS FIRES IN WESTERN ONTARIO.
KEY MESSAGE 3: A COLD FRONTAL BOUNDARY AND UPPER LEVEL TROUGH
ARE BOTH EXPECTED TO CROSS THE FORECAST AREA TUESDAY NIGHT INTO
WEDNESDAY, BRINGING ANOTHER ROUND OF SHOWERS WITH EMBEDDED
THUNDERSTORMS. BY THURSDAY MORNING SURFACE HIGH PRESSURE WILL
BEGIN TO RIDGE INTO THE NORTH COUNTRY, BRINGING A RETURN TO
DRIER WEATHER ONCE AGAIN. HEADED INTO THE WEEKEND NOT A LOT OF
MODEL AGREEMENT ON WHAT WILL HAPPEN. WILL MONITOR THE MID WEEK
PERIOD FOR POTENTIAL STRONG OR SEVERE STORMS AS WELL AS HEAVY
RAINFALL. HIGHS FOR THE MID AND LATE WEEK ARE EXPECTED TO BE
AROUND THE 70S AND LOWER 80S WITH LOWS IN THE UPPER 40S TO LOWER
60S, THOUGH THIS MAY DEPEND ON HOW EXACTLY THE ATMOSPHERIC
PATTERN SHAPES UP DURING THIS PERIOD.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
THROUGH 18Z SUNDAY...MAINLY VFR THIS AFTERNOON WITH SCATTERED
THUNDERSTORMS AS A WARM FRONT APPROACHES. SOME TSRA WILL
CONTINUE TO DEVELOP THROUGH THE EVENING HOURS, MAINLY IN THE
SOUTH AND WEST PORTIONS OF OUR CWA, AS INDICATED BY THE PROB30S
FOR RUT AND SLK. OTHER TERMINALS COULD SEE SOME LOCALLY HEAVE
DOWNPOURS THAT BRING DOWN VISIBILITIES FOR A SHORT PERIOD OF
TIME. OUTSIDE OF THE SHOWERS, WE WILL SEE PRIMARILY SOUTHERLY
WINDS WITH GUSTS INTO THE MID 20 KNOTS. SHOWERS WILL CLEAR
AFTER 00Z.
OUTLOOK...
SUNDAY NIGHT: VFR. NO SIG WX.
MONDAY: VFR. NO SIG WX.
MONDAY NIGHT: VFR. NO SIG WX.
TUESDAY: VFR. LIKELY SHRA, CHANCE TSRA.
TUESDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. DEFINITE
SHRA, SLIGHT CHANCE TSRA.
WEDNESDAY: MAINLY MVFR, WITH AREAS IFR POSSIBLE. LIKELY SHRA,
CHANCE TSRA.
WEDNESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT
CHANCE SHRA, SLIGHT CHANCE TSRA.
THURSDAY: VFR. SLIGHT CHANCE SHRA, SLIGHT CHANCE TSRA.
BTV WATCHES/WARNINGS/ADVISORIES
VT...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR VTZ001>011-
016>021.
NY...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR NYZ026>031-
034-035-087.
WHAT HAS CHANGED...KUTIKOFF
DISCUSSION...MYSKOWSKI/NEILES
AVIATION...LANGBAUER
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