458
FXUS61 KBUF 081720
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
120 PM EDT TUE SEP 8 2026
WHAT HAS CHANGED
MINOR CHANGES TO THE FORECAST WITH THIS UPDATE.
KEY MESSAGES
1) A COLD FRONT WILL CROSS THE EASTERN GREAT LAKES WEDNESDAY THROUGH
WEDNESDAY NIGHT, PRODUCING SHOWERS AND SCATTERED THUNDERSTORMS. A
FEW STORMS MAY BE SEVERE WITH ISOLATED DAMAGING WIND GUSTS THE
PRIMARY HAZARD.
2) A FEW SHOWERS MAY LINGER THURSDAY MAINLY ACROSS THE SOUTHERN
TIER, WITH DRY WEATHER RETURNING FRIDAY THROUGH SATURDAY.
DISCUSSION
KEY MESSAGE 1...A COLD FRONT WILL CROSS THE EASTERN GREAT LAKES
WEDNESDAY THROUGH WEDNESDAY NIGHT, PRODUCING SHOWERS AND SCATTERED
THUNDERSTORMS. A FEW STORMS MAY BE SEVERE WITH ISOLATED DAMAGING
WIND GUSTS THE PRIMARY HAZARD.
INCREASING WARM ADVECTION AND MOISTURE TRANSPORT AHEAD OF THE NEXT
SYSTEM WILL BRING AN EAST TO WEST INCREASE IN HIGH CLOUDS THIS
AFTERNOON, LOWERING INTO A MID LEVEL DECK TONIGHT. DRY WEATHER WILL
PREVAIL THROUGH DAYBREAK WEDNESDAY.
ONGOING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL SUPPORT AN AREA
OF SHOWERS ACROSS THE NORTH COUNTRY FROM MIDDAY INTO THE AFTERNOON.
A FEW SCATTERED LIGHT SHOWERS MAY ALSO CLIP WESTERN NY, MAINLY ALONG
AND NORTH OF THE NYS THRUWAY WEDNESDAY MORNING THROUGH MID
AFTERNOON.
THE MAIN AREA OF SHOWERS AND SCATTERED THUNDERSTORMS WILL ARRIVE
LATE WEDNESDAY AFTERNOON THROUGH LATE EVENING AS A BROKEN BAND OF
SHOWERS AND SCATTERED THUNDERSTORMS CROSS THE REGION. A SHARP MID
LEVEL TROUGH WILL CROSS ONTARIO AND QUEBEC, WITH THE SOUTHERN EXTENT
OF HEIGHT FALLS SPREADING EAST ACROSS THE GREAT LAKES AND PROVIDING
SOME LARGE SCALE FORCING FOR ASCENT. THE MAIN LOW LEVEL FOCUS FOR
CONVECTION WILL BE A PRE-FRONTAL TROUGH THAT IS FORECAST TO REACH
THE EASTERN GREAT LAKES BY EARLY EVENING. THE SYSTEM WILL CAPTURE A
NARROW PLUME OF DEEP MOISTURE, WITH PWAT VALUES BRIEFLY EXCEEDING 2
INCHES LATE WEDNESDAY JUST AHEAD OF THE PRE-FRONTAL TROUGH.
ANY THUNDERSTORMS WILL PRODUCE BRIEF, TORRENTIAL DOWNPOURS, BUT FAST
STORM MOTION WILL LIKELY KEEP THE FLOOD RISK LOW. STRONG SHEAR WILL
OVERSPREAD THE AREA WEDNESDAY, WITH BOUNDARY LAYER FLOW INCREASING
TO 40+ KNOTS. POOR MID LEVEL LAPSE RATES WILL KEEP INSTABILITY
SOMEWHAT LIMITED, BUT THE LATEST GUIDANCE SUGGESTS THAT SUFFICIENT
INSTABILITY MAY DEVELOP TO SUPPORT SOME SEVERE RISK FROM LATE
AFTERNOON THROUGH MID TO LATE EVENING. THE LARGELY UNIDIRECTIONAL
WIND PROFILES WILL SUPPORT LOCALIZED DAMAGING WIND GUSTS AS THE
PRIMARY HAZARD.
SHOWERS AND SCATTERED THUNDERSTORMS WILL TAPER OFF FROM NORTHWEST TO
SOUTHEAST OVERNIGHT.
KEY MESSAGE 2...A FEW SHOWERS MAY LINGER THURSDAY MAINLY ACROSS THE
SOUTHERN TIER, WITH DRY WEATHER RETURNING FRIDAY THROUGH SATURDAY.
THE COLD FRONT WILL STALL ACROSS OHIO AND PA THURSDAY AS A WEAK
BAROCLINIC WAVE MOVES EAST DOWN THE BOUNDARY. THIS WAVE WILL PRODUCE
AN AREA OF ORGANIZED RAIN TO OUR SOUTH ACROSS OHIO AND PA. MOST OF
THIS WILL MISS OUR REGION, ALTHOUGH A FEW SHOWERS MAY DEVELOP ACROSS
THE SOUTHERN TIER. OTHERWISE, THE REST OF THE AREA WILL BE MAINLY
DRY THURSDAY WITH A GOOD DEAL OF CLOUD COVER NORTH OF THE FRONTAL
WAVE. THE FRONT WILL THEN ACCELERATE SOUTHEAST AND INTO THE MID
ATLANTIC THURSDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE CENTRAL
GREAT LAKES.
DRY WEATHER AND SUNSHINE WILL RETURN FRIDAY THROUGH SATURDAY AS HIGH
PRESSURE DRIFTS FROM THE GREAT LAKES EAST TO NEW ENGLAND. THE NEXT
CHANCE OF SHOWERS MAY ARRIVE BY SUNDAY AS THE NEXT MID LEVEL TROUGH
AND COLD FRONT MOVE INTO THE GREAT LAKES.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
VFR WILL PREVAIL THROUGH TONIGHT. HIGH CLOUDS WILL INCREASE FROM
WEST TO EAST THIS AFTERNOON, THEN LOWER INTO A MID LEVEL DECK
TONIGHT AS WARM ADVECTION AND MOISTURE TRANSPORT INCREASE AHEAD OF
THE NEXT SYSTEM.
WEDNESDAY, ONGOING WARM ADVECTION AND MOISTURE TRANSPORT WILL
PRODUCE AN AREA OF SHOWERS ACROSS THE NORTH COUNTRY FROM MIDDAY INTO
THE AFTERNOON. A FEW SCATTERED LIGHT SHOWERS MAY ALSO CLIP AREAS
ALONG AND NORTH OF THE NYS THRUWAY. CIGS/VSBY WILL REMAIN VFR IN
MOST LOCATIONS THROUGH MID TO LATE AFTERNOON, WITH THE EXCEPTION OF
THE NORTH COUNTRY WHERE AN MVFR CLOUD DECK WILL LIKELY DEVELOP. IT
WILL BECOME QUITE BREEZY, ESPECIALLY ACROSS THE NIAGARA FRONTIER
NORTHEAST OF LAKE ERIE WHERE SURFACE GUSTS MAY REACH OR EXCEED 30
KNOTS IN THE AFTERNOON.
THE BULK OF THE SHOWERS AND SCATTERED THUNDERSTORMS WILL CROSS THE
REGION IN A BROKEN BAND LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING AS A PRE-FRONTAL TROUGH CROSSES THE EASTERN GREAT LAKES. THE
THUNDERSTORMS AND HEAVIER DOWNPOURS WILL PRODUCE LOCAL/BRIEF IFR
CONDITIONS AND LOCALIZED GUSTY WINDS. THE RAIN WILL TAPER OFF FROM
NORTHWEST TO SOUTHEAST OVERNIGHT. POST-FRONTAL LOW STRATUS WILL
BRING WIDESPREAD MVFR CIGS OVERNIGHT, WITH SOME IFR ACROSS HIGHER
TERRAIN.
OUTLOOK...
THURSDAY...MVFR CIGS EARLY, IMPROVING TO VFR. A FEW SHOWERS POSSIBLE
ACROSS THE SOUTHERN TIER.
FRIDAY THROUGH SATURDAY...MAINLY VFR.
SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MARINE
LOW PRESSURE WILL TRACK EAST ACROSS HUDSON BAY WEDNESDAY BEFORE
REACHING NORTHERN QUEBEC THURSDAY, WITH A TRAILING COLD FRONT
CROSSING THE LOWER GREAT LAKES WEDNESDAY NIGHT. A BELT OF ENHANCED
WINDS WILL DEVELOP SOUTH OF THE LOW, WITH SOUTHERLY WINDS INCREASING
ON THE LOWER GREAT LAKES TONIGHT, THEN INCREASING FURTHER AND
VEERING TO THE SOUTHWEST WEDNESDAY. WINDS AND WAVES WILL APPROACH
LOW END SMALL CRAFT ADVISORY CRITERIA BY WEDNESDAY AFTERNOON ON BOTH
LAKES, WITH WINDS PEAKING WEDNESDAY EVENING. ELEVATED WINDS AND
WAVES WILL LIKELY CONTINUE THROUGH THURSDAY EVENING ON LAKE ONTARIO.
HIGH PRESSURE WILL BUILD EAST ACROSS THE GREAT LAKES THURSDAY NIGHT
THROUGH FRIDAY WITH SUBSIDING WINDS AND WAVES.
BUF WATCHES/WARNINGS/ADVISORIES
NY...NONE.
MARINE...NONE.
DISCUSSION...HITCHCOCK
AVIATION...HITCHCOCK
MARINE...HITCHCOCK
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