943
FXUS61 KBUF 210528
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
128 AM EDT MON SEP 21 2026
WHAT HAS CHANGED
ONLY MINOR CHANGES WITH THIS FORECAST UPDATE.
KEY MESSAGES
1) BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH THE UPCOMING
WEEK, WITH A FEW SHOWERS POSSIBLE AT TIMES MID-WEEK.
DISCUSSION
KEY MESSAGE 1...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
UPCOMING WEEK, WITH A FEW SHOWERS POSSIBLE AT TIMES MID-WEEK.
OVER THE NEXT FEW DAYS THE BULK OF BROAD UPPER LEVEL TROUGHING OVER
EASTERN CANADA WILL SLOWLY DRIFT EASTWARD AND OUT TO SEA. AS IT DOES
SO...THE FAR SOUTHWESTERN EXTENT OF THIS TROUGH WILL EVENTUALLY
BREAK OFF AND MERGE WITH A PAIR OF SHORTWAVES MAKING THEIR WAY
ACROSS THE OHIO VALLEY...RESULTING IN THE FORMATION OF A MODEST
CLOSED LOW THAT WILL THEN SLIDE SOUTHEASTWARD ACROSS THE OHIO
VALLEY/MID-ATLANTIC STATES DURING THE MID-LATE WEEK PERIOD.
MEANWHILE AT THE SURFACE...EXPANSIVE COOL CANADIAN HIGH PRESSURE
WILL SLOWLY DRIFT FROM ONTARIO TO QUEBEC PROVINCES AND STRENGTHEN
THROUGH WEDNESDAY...THEN WILL REMAIN IN PLACE THROUGH THE END OF THE
WEEK WHILE A SURFACE LOW DEVELOPS OFF THE MID-ATLANTIC COASTLINE IN
RESPONSE TO THE APPROACHING CUTOFF UPPER LOW AND ATTENDANT
DCVA/HEIGHT FALLS ALOFT.
AS A RESULT OF ALL THIS...OUR REGION WILL REMAIN UNDER A PREVAILING
NORTHEASTERLY TO EASTERLY LOW LEVEL FLOW RIGHT THROUGH THE WEEK...
RESULTING IN AN EXTENDED PERIOD OF BELOW NORMAL TEMPERATURES. THE
COOLEST DAYS WILL BE TODAY AND TUESDAY WHEN HIGHS WILL RANGE FROM
THE UPPER 50S TO THE LOWER 60S IN MOST AREAS...AND NIGHTLY LOWS WILL
GENERALLY RANGE THROUGH THE 40S. THE EXCEPTION TO THE LATTER WILL BE
ACROSS THE NORTH COUNTRY WHERE SKIES SHOULD CLEAR ENOUGH TONIGHT/
REMAIN CLEAR ENOUGH TUESDAY NIGHT TO ALLOW LOWS IN THE UPPER 30S...
WHICH MAY ALLOW FOR SOME ISOLATED FROST IN A FEW SPOTS. GRADUAL DAY-
TO-DAY WARMING WILL THEN FOLLOW FOR THE REST OF THE WEEK AS OUR
AIRMASS SLOWLY MODIFIES.
WITH RESPECT TO PRECIPITATION CHANCES...THE APPROACHING OHIO VALLEY
SHORTWAVES/DEVELOPING CLOSED UPPER LOW SHOULD ENCOURAGE WEAK SURFACE
TROUGHING TO OUR SOUTH TO TEMPORARILY EDGE BACK NORTHWARD AGAIN
BETWEEN MONDAY NIGHT AND WEDNESDAY...WHEN MOISTURE/LIFT FROM THESE
FEATURES MAY ALLOWING FOR A FEW SPOTTY LIGHT SHOWERS AT TIMES ACROSS
THE SOUTHERN TIER. OTHERWISE THE STRONG SURFACE HIGH AND LARGELY
CONFLUENT FLOW ALOFT SHOULD KEEP OUR REGION DRY THROUGH THE WORK
WEEK...BEFORE THE AFOREMENTIONED COASTAL SYSTEM POTENTIALLY THROWS A
FEW SHOWERS BACK ACROSS OUR EASTERN ZONES NEXT WEEKEND...WITH THIS
POTENTIAL DEPENDENT UPON JUST HOW FAR WEST THIS FEATURE ULTIMATELY
GETS.
AVIATION /06Z MONDAY THROUGH FRIDAY/
CYCLONIC W'ERLY TO WNW'ERLY FLOW ALOFT, EMBEDDED DISTURBANCES, AND
WIDESPREAD MID-LEVEL TO PRIMARILY UPPER-LEVEL CLOUDINESS GENERATED
BY THOSE DISTURBANCES AFFECT WESTERN AND CENTRAL NY THROUGH
06Z/TUES. AT THE SURFACE, A RIDGE CONTINUES TO BUILD INTO OUR AREA
AS THE PARENT HIGH PRESSURE CENTER WOBBLES E'WARD FROM NORTHERN ON
TO CENTRAL QC. OUR REGIONAL SURFACE WINDS TREND LIGHT AND VARIABLE
THROUGH ~07Z/MON AND THEN NE'ERLY AROUND 5 TO 10 KNOTS THROUGH
06Z/TUES.
THE AFOREMENTIONED SURFACE RIDGE IS EXPECTED TO BE ACCOMPANIED BY
DRY WEATHER AND MAINLY VFR VISIBILITY THROUGH THE TAF PERIOD.
HOWEVER, FOG HAS DEVELOPED IN/NEAR THE BLACK RIVER VALLEY IN NORTH-
CENTRAL NY, INCLUDING AT/NEAR KART. THIS FOG SHOULD DISSIPATE AROUND
07Z/MON, WHEN A TIGHTENING MSLP GRADIENT SHOULD ALLOW LOW-LEVEL FLOW
TO STRENGTHEN, INCLUDING WITH INCREASING ELEVATION, AND ENCOURAGE
BOUNDARY LAYER MIXING.
N'ERLY TO NE'ERLY MEAN LOW-LEVEL FLOW OF SUFFICIENTLY-COLD/MOIST AIR
OVER AND DOWNWIND OF THE ~72F EASTERN GREAT LAKES WILL ALLOW
ISOLATED TO WIDESPREAD LAKE-EFFECT AND UPSLOPE STRATOCUMULI WITH
BASES NEAR 1.5KFT TO 2KFT AGL TO AFFECT OUR REGION THROUGH ~15Z/MON.
THE COVERAGE OF THESE LOW CLOUDS IS EXPECTED TO BE GREATEST BETWEEN
~08Z/MON AND ~15Z/MON. FROM ~15Z/MON TO ~23Z/MON, SCATTERED TO
WIDESPREAD LOW CLOUDS WITH BASES NEAR 2.5FKT TO 3.5KFT AGL ARE
EXPECTED OVER WESTERN AND CENTRAL NY AS DIURNAL DESTABILIZATION AND
ASSOCIATED CONVECTIVE MIXING OF THE BOUNDARY LAYER ALLOW
STRATOCUMULI TO EVOLVE INTO CUMULI. AFTER ~23Z/MON, ISOLATED TO
SCATTERED LAKE-EFFECT AND UPSLOPE STRATOCUMULI WITH BASES NEAR 2KFT
TO 4KFT AGL ARE EXPECTED AMIDST A NE'ERLY TO E'ERLY MEAN LOW-LEVEL
FLOW OF SUFFICIENTLY-COLD/MOIST AIR IN THE EASTERN GREAT LAKES
REGION.
OUTLOOK...
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...PERIODIC RAIN SHOWERS WITH
MVFR POSSIBLE, ESPECIALLY ACROSS THE WESTERN SOUTHERN TIER.
THURSDAY AND FRIDAY...DRY WEATHER AND MAINLY VFR EXPECTED. FOG
POSSIBLE IN INTERIOR WESTERN AND CENTRAL NY AT AND AROUND DAYBREAK
FRIDAY, ESPECIALLY IN/NEAR RIVER AND LAKE VALLEYS.
MARINE
EXPANSIVE SURFACE HIGH PRESSURE OVER ONTARIO PROVINCE WILL BUILD
ACROSS QUEBEC AND STRENGTHEN THROUGH MIDWEEK...WHILE WEAK SURFACE
TROUGHING SLIDES EASTWARD ACROSS THE OHIO VALLEY AND MID-ATLANTIC
STATES. THE RESULTING PRESSURE GRADIENT WILL MAINTAIN A MODERATE TO
FAIRLY BRISK FLOW ACROSS THE LOWER GREAT LAKES THROUGH MIDWEEK THAT
WILL ALSO GRADUALLY VEER FROM NORTHEASTERLY TO EASTERLY OVER TIME.
THIS WILL ALLOW FOR SCA-LEVEL CONDITIONS ACROSS THE NEARSHORE WATERS
OF BOTH LAKES TODAY...WITH THESE THEN BECOMING MORE CONFINED TO
AREAS FROM SODUS BAY WESTWARD TONIGHT/TUESDAY...AND THEN FROM HAMLIN
BEACH TO THE NIAGARA RIVER TUESDAY NIGHT/WEDNESDAY AS THE FLOW VEERS
MORE EASTERLY. ANY LINGERING SCA-LEVEL CONDITIONS SHOULD THEN
SUBSIDE WEDNESDAY NIGHT AS THE SURFACE RIDGE BUILDS FURTHER
SOUTHWARD AND RESULTS IN A WEAKENING OF THE PRESSURE GRADIENT ACROSS
OUR REGION...ALONG WITH A COMMENSURATE LOWERING OF WINDS AND WAVE
ACTION.
BUF WATCHES/WARNINGS/ADVISORIES
NY...BEACH HAZARDS STATEMENT THROUGH WEDNESDAY EVENING FOR NYZ001-
002.
BEACH HAZARDS STATEMENT THROUGH WEDNESDAY MORNING FOR NYZ003-
004.
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR NYZ005-006.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT TUESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LOZ030-044-045.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR LOZ042.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LOZ043.
DISCUSSION...JJR
AVIATION...JASZKA
MARINE...JJR
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