449
FXUS61 KBUF 180134
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
934 PM EDT SUN AUG 17 2025
SYNOPSIS
CANADIAN HIGH PRESSURE SLIDING FROM ONTARIO TO QUEBEC WILL BRING
COOLER AND DRIER WEATHER THROUGH MONDAY. AN AREA OF LOW PRESSURE
WILL THEN APPROACH THE LOWER GREAT LAKES THROUGH MIDWEEK AND BRING A
PERIOD OF UNSETTLED WEATHER...WITH HIGH PRESSURE AND DRIER WEATHER
THEN GRADUALLY RETURNING THURSDAY AND FRIDAY.
NEAR TERM /THROUGH MONDAY/
CANADIAN HIGH PRESSURE BUILDING FROM ONTARIO TO QUEBEC OVERNIGHT/
MONDAY WILL BRING CLEARING SKIES FROM NORTH TO SOUTH OVERNIGHT...
WITH DRY WEATHER OTHERWISE PREVAILING THROUGH MONDAY. WITH A COOLER
AND DRIER AIRMASS OVERSPREADING OUR REGION...LOWS TONIGHT WILL
SETTLE INTO THE MID 40S ACROSS THE NORTH COUNTRY AND INTO THE
LOWER TO MID 50S ACROSS MOST AREAS SOUTH OF LAKE ONTARIO...WITH
HIGHS ON MONDAY THEN RANGING FROM THE UPPER 60S ACROSS THE HIGHER
TERRAIN TO THE LOWER TO MID 70S ELSEWHERE.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
DRY AND COMFORTABLE WEATHER WILL CONTINUE TO PREVAIL MONDAY NIGHT
THROUGH MUCH OF TUESDAY AS SFC HIGH PRESSURE DRIFTS SOUTHEAST ACROSS
QUEBEC TO THE CANADIAN MARITIMES. TEMPERATURES WILL BE WARMER
COMPARED TO MONDAY THOUGH STILL WITHIN A FEW DEGREES OF AVERAGE FOR
MID-AUGUST. A POSITIVELY TILTED MID-LEVEL SHORTWAVE AND ASSOCIATED
INVERTED SFC TROUGH DRIFTING SOUTHEAST ACROSS THE GREAT LAKES WILL
THEN INTERSECT A PLUME OF ATLANTIC-BASED MOISTURE ADVECTING
NORTHWARD FROM THE APPALACHIANS TO INCREASE CHANCES FOR SHOWERS
ACROSS THE FORECAST AREA LATE TUESDAY THROUGH WEDNESDAY. FAIRLY
LARGE RUN-TO-RUN INCONSISTENCIES NOTED AMONG THE DETERMINISTIC
MODELS REGARDS TO IN COVERAGE, TIMING AND INTENSITY OF PRECIP DURING
THIS TIMEFRAME THOUGH GLOBAL AND NBM ENSEMBLES HAVE A MORE DISTINCT
TREND TOWARDS A DRIER OVERALL FORECAST. WHILE THERE MAY BE JUST
ENOUGH ELEVATED INSTABILITY PRESENT FOR A FEW THUNDERSTORMS,
GUIDANCE HAS LIKEWISE TRENDED DOWNWARDS WITH THIS POTENTIAL AS WELL.
MID TO UPPER LEVEL RIDGING BUILDING BACK ACROSS THE GREAT LAKES WILL
CAUSE AN EXPANSE OF SFC HIGH PRESSURE TO BUILD BACK SOUTHWARD ACROSS
ON/QC PROVINCES AND NEW ENGLAND MOVING INTO WEDNESDAY NIGHT. THIS
WILL CAUSE PRECIP CHANCES TO TAPER OFF OVERNIGHT, THOUGH CAN'T RULE
OUT SOME LINGERING SPOTTY SHOWERS WITH LINGERING LOW LEVEL MOISTURE
AND TROUGH AXIS CROSSING THE REGION.
LONG TERM /THURSDAY THROUGH SUNDAY/
A PROGRESSIVE WEDGE OF SFC HIGH PRESSURE WILL BUILD SOUTH INTO THE
REGION FROM CANADA THURSDAY AS LONGWAVE TROUGHING SHIFTS EAST TO NEW
ENGLAND. OUTSIDE OF A FEW STRAY SHOWERS ACROSS THE SOUTHERN TIER OR
FINGER LAKES THURSDAY, MAINLY DRY WEATHER WILL RETURN THROUGH AT
LEAST EARLY SATURDAY WITH A MODEST WARMING TREND.
A DEEP CLOSED LOW MOVING SOUTHEAST ACROSS ONTARIO PROVINCE WILL THEN
CAUSE A PAIR OF FRONTAL BOUNDARIES TO MOVE THROUGH THE REGION OVER
THE WEEKEND. THIS WILL BRING ANOTHER ROUND OF SHOWER/TSTORM CHANCES
TO THE FORECAST AREA, THOUGH MODELS REMAIN SOMEWHAT SPLIT ON THE
EXTENT AND PLACEMENT OF NORTHWARD MOISTURE ADVECTION IN THE WARM
SECTOR SATURDAY AND THE TIMING OF THE MAIN COLD FRONT BETWEEN LATER
SATURDAY AND SUNDAY.
TEMPS OVER THE WEEKEND WILL LARGELY DEPEND ON THE TIMING OF THIS
FRONT, THOUGH BASED ON CURRENT MODEL GUIDANCE CONSENSUS A NOTABLE
COOLDOWN SHOULD OCCUR BY SUNDAY.
AVIATION /02Z MONDAY THROUGH FRIDAY/
LINGERING IFR/MVFR CEILINGS SOUTH OF LAKE ONTARIO WILL GRADUALLY
IMPROVE BACK TO UNLIMITED VFR FROM NORTH TO SOUTH THROUGH 06Z
AS CANADIAN HIGH PRESSURE AND DRIER AIR RIDGES SOUTHEASTWARD
FROM ONTARIO PROVINCE...WITH UNLIMITED VFR CONDITIONS THEN
CONTINUING TO PREVAIL OVERNIGHT. CANNOT COMPLETELY RULE OUT SOME
PATCHY FOG WITHIN THE SOUTHERN TIER VALLEYS OVERNIGHT ONCE SKIES
CLEAR...BUT CURRENT FEELING IS THAT THERE MAY BE JUST ENOUGH OF
A SURFACE GRADIENT IN PLACE TO KEEP THIS FROM FORMING.
ON MONDAY...THE SURFACE HIGH WILL DRIFT EASTWARD INTO QUEBEC...WITH
WIDESPREAD VFR CONDITIONS PREVAILING.
OUTLOOK...
MONDAY NIGHT...MAINLY VFR.
TUESDAY AND TUESDAY NIGHT...MAINLY VFR. ISOLATED TO SCATTERED
SHOWERS.
WEDNESDAY...LOCALIZED CIG/VSBY RESTRICTIONS POSSIBLE ESPECIALLY
EARLY IN THE DAY, OTHERWISE MAINLY VFR WITH DECREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS.
THURSDAY AND FRIDAY...VFR.
MARINE
MODERATELY BRISK NORTHEASTERLIES WILL MAINTAIN ADVISORY-LEVEL
CONDITIONS ON LAKE ERIE THROUGH MOST OF TONIGHT...AND THROUGH MUCH
OF MONDAY ON LAKE ONTARIO. WINDS WILL THEN TURN MORE EASTERLY AND
GRADUALLY WEAKEN...WITH GRADUALLY SUBSIDING WAVE ACTION THROUGH
MONDAY NIGHT.
BUF WATCHES/WARNINGS/ADVISORIES
NY...BEACH HAZARDS STATEMENT THROUGH MONDAY AFTERNOON FOR
NYZ001>006.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT MONDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR
LOZ042>045.
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...PP
LONG TERM...PP
AVIATION...JJR/TMA
MARINE...JJR
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