910
FXUS61 KBUF 211808
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
208 PM EDT THU MAY 21 2026
WHAT HAS CHANGED
FROST ADVISORY EXPANDED TO INCLUDE OSWEGO AND ALLEGANY COUNTIES
TONIGHT.
KEY MESSAGES
1) BELOW NORMAL TEMPERATURES CONTINUE THROUGH SATURDAY.
2) WIDESPREAD SOAKING RAIN FRIDAY NIGHT INTO SATURDAY NIGHT.
DISCUSSION
KEY MESSAGE 1...BELOW NORMAL TEMPERATURES CONTINUE THROUGH SATURDAY.
A COOL DRY AIRMASS WILL REMAIN IN PLACE AS HIGH PRESSURE OVER THE
GREAT LAKES MOVES EAST-SOUTHEAST THROUGH FRIDAY. THE CENTER OF
THE SURFACE HIGH WILL MOVE OVER NORTHERN NEW YORK TONIGHT.
MOSTLY CLEAR SKIES AND LIGHT WINDS WILL PROVIDE A FAVORABLE
SETUP FOR RADIATIONAL COOLING. LOW TEMPERATURES WILL BE FROM
THE LOWER TO MID 30S ACROSS THE INTERIOR PORTIONS EAST OF LAKE
ONTARIO AND THE INTERIOR SOUTHERN TIER, AND UPPER 30S AND LOWER
40S ACROSS WESTERN NEW YORK. A FROST ADVISORY IS IN EFFECT FOR
THE EASTERN LAKE ONTARIO REGION AND ALLEGANY COUNTY TONIGHT
WHERE SENSITIVE VEGETATION MAY BE HARMED IF NOT PROTECTED.
KEY MESSAGE 2...WIDESPREAD SOAKING RAIN FRIDAY NIGHT INTO SATURDAY
NIGHT.
A WAVE OF LOW PRESSURE WILL MOVE INTO THE GREAT LAKES ALONG AN
ADVANCING WARM FRONT FROM THE OHIO VALLEY FRIDAY NIGHT AND
SATURDAY. THIS WILL BRING A PERIOD OF WIDESPREAD, SOAKING RAIN
ALONG WITH POSSIBLE EMBEDDED THUNDERSTORMS. A DEEP SOUTHERLY FLOW
AHEAD OF THE SURFACE LOW WILL ADVANCE NORTHWARD ACROSS THE OHIO
VALLEY, AS THE WARM FRONT APPROACHES WESTERN NEW YORK. WARM AIR
ADVECTION AND INCREASING MOISTURE WILL RESULT IN SHOWERS
STARTING TO MOVE INTO WESTERN NEW YORK FRIDAY NIGHT.
A SHORTWAVE TROUGH WILL CATCH UP WITH THE SURFACE LOW OVER THE OHIO
VALLEY, SPREADING WIDESPREAD MODERATE TO HEAVY RAIN ACROSS WESTERN
NEW YORK SATURDAY. A STRONG AREA OF HIGH PRESSURE OVER THE CANADIAN
MARITIMES IS EXPECTED TO MAINTAIN MOSTLY DRY CONDITIONS EAST OF LAKE
ONTARIO. ENHANCED RAINFALL IS POSSIBLE ACROSS WESTERN NEW YORK
WHERE A STRONG LOW-LEVEL JET INTERACTS WITH A VERY MOIST AIRMASS.
UNCERTAINTY EXIST IN THE EXACT LOCATION OF THE ENHANCED RAINFALL,
BUT INSTABILITY WILL BE LIMITED IN THIS ENVIRONMENT, HOWEVER A
FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE.
THE UPPER LEVEL RIDGE AND SURFACE HIGH WILL MOVE EAST SATURDAY NIGHT
WHILE LARGE SCALE ASCENT AND MOISTURE WILL MOVE INTO THE EASTERN
GREAT LAKES REGION. SHOWERS WILL CONTINUE ACROSS WESTERN NEW YORK
WHILE SPREADING INTO NORTH-CENTRAL NEW YORK. THE CURRENT FORECAST
INCLUDES RAINFALL AMOUNTS OF 1.0-1.5" ACROSS WESTERN NEW YORK
AND 0.25-0.75" ACROSS THE EASTERN LAKE ONTARIO REGION FRIDAY NIGHT
THROUGH SATURDAY NIGHT. THIS AMOUNT OF RAINFALL HAS THE POTENTIAL
TO CAUSE PONDING AND MINOR FLOODING OF LOW LYING AREAS. RISES
ON RIVERS AND CREEKS IS EXPECTED, WITH A FEW POSSIBLY REACHING
ACTION STAGE, BUT WIDESPREAD FLOODING IS NOT EXPECTED.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
HIGH LEVEL CLOUDINESS WILL CONTINUE TO SHIFT OFF TO THE SOUTHEAST
THIS AFTERNOON LEAVING MAINLY CLEAR SKIES THROUGH 00Z FRIDAY.
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD WITH
INCREASING MID AND HIGH LEVEL CLOUDS, ESPECIALLY AFTER 12Z FRIDAY.
NE WINDS AROUND 10 KNOTS THIS AFTERNOON WILL BECOME LIGHT EASTERLY
TONIGHT, WITH E/NE WINDS INCREASING TO 10-15 KNOTS FRIDAY.
OUTLOOK...
SATURDAY...MVFR/VFR DETERIORATING TO MVFR/IFR WITH WIDESPREAD RAIN
SHOWERS.
SUNDAY...MVFR/IFR WITH RAIN SHOWERS IN THE MORNING, THEN IMPROVING
TO VFR.
MONDAY...MAINLY VFR WITH A CHANCE OF RAIN SHOWERS.
TUESDAY... MAINLY VFR.
MARINE
NORTHEAST WINDS TO NEAR 20 KNOTS WILL CONTINUE THIS AFTERNOON ON
LAKE ERIE WITH CHOPPY CONDITIONS. THE STRONGEST WINDS ARE EXPECTED
SOUTH OF DUNKIRK WITH WAVE HEIGHTS NEARING 4 FEET. WINDS WILL TREND
WEAKER ON LAKE ONTARIO, ALTHOUGH SOME CHOP WILL CONTINUE THIS
AFTERNOON.
WINDS WILL RELAX TONIGHT AND FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE LOWER GREAT LAKES.
A STRONGER PRESSURE GRADIENT DEVELOPS LATE FRIDAY AND SATURDAY AS A
WAVE AND WARM FRONT MOVE INTO THE GREAT LAKES. EASTERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS ON THE WESTERN END OF LAKE ONTARIO WITH
SMALL CRAFT AND BEACH HAZARDS HEADLINES LIKELY DURING THIS TIME
PERIOD. WINDS WILL TREND WEAKER ON LAKE ERIE.
BUF WATCHES/WARNINGS/ADVISORIES
NY...FROST ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT FRIDAY FOR
NYZ006>008-021.
MARINE...NONE.
DISCUSSION...TMA
AVIATION...TMA
MARINE...TMA
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