191
FXUS61 KBUF 201043
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
643 AM EDT SUN SEP 20 2026
WHAT HAS CHANGED
LOWERED PRECIPITATION CHANCES AND AMOUNTS ACROSS FAR WESTERN NEW
YORK THROUGH TODAY.
KEY MESSAGES
1) SOME SHOWERS FROM THE SOUTHERN TIER NORTHEASTWARD INTO THE NORTH
COUNTRY THIS MORNING, THEN TURNING DRIER THROUGH THE REST OF THE DAY.
2) BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH MOST OF THE
UPCOMING WEEK, WITH A FEW SHOWERS POSSIBLE AT TIMES MIDWEEK.
DISCUSSION
KEY MESSAGE 1...SOME SHOWERS FROM THE SOUTHERN TIER NORTHEASTWARD
INTO THE NORTH COUNTRY THIS MORNING, THEN TURNING DRIER THROUGH THE
REST OF THE DAY.
AS OF THIS WRITING A WAVE OF LOW PRESSURE IS FOUND OVER THE CENTRAL
MISSISSIPPI VALLEY...WITH AN INVERTED TROUGH EXTENDING NORTHEASTWARD
FROM THIS FEATURE INTO WESTERN NEW YORK. REGIONAL RADARS SHOW THAT
THE VAST MAJORITY OF ANY SHOWERS ATTENDANT TO THE TROUGH CONTINUE TO
PASS BY LARGELY TO OUR SOUTH...WITH JUST SOME RATHER SPOTTY ACTIVITY
CURRENTLY NOTED ACROSS THE WESTERN SOUTHERN TIER.
AS WE PUSH THROUGH THE EARLY PORTIONS OF THIS MORNING...THE TROUGH
AXIS WILL TEMPORARILY EXTEND FURTHER NORTHEASTWARD ACROSS NEW YORK
STATE...WITH AN EMBEDDED WEAK WAVE OF LOW PRESSURE FORMING OVER NE
OHIO/NW PENNSYLVANIA IN RESPONSE TO SHORTWAVE ENERGY PUSHING
EASTWARD ACROSS THE OHIO VALLEY. AT THE SAME TIME...A MODEST LOW
LEVEL JET WILL ALSO DEVELOP FROM NORTH-CENTRAL PA INTO NORTH-CENTRAL
NEW YORK. AS ALL THIS OCCURS...INCREASING ISENTROPIC UPGLIDE/
MOISTURE ALONG THE ADVANCING TROUGH WILL COMBINE WITH LOW LEVEL
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET...LEADING TO A BRIEF
PERIOD OF SOMEWHAT MORE NUMEROUS SHOWERS FROM THE INTERIOR SOUTHERN
TIER NORTHEASTWARD ACROSS PORTIONS OF THE FINGER LAKES AND NORTH
COUNTRY. THESE SHOULD BE MOST NUMEROUS ACROSS THE NORTH COUNTRY
WHERE LIFT FROM THE LLJ WILL BE MAXIMIZED...WHILE ACROSS THE NIAGARA
FRONTIER SHOWER COVERAGE SHOULD REMAIN MUCH MORE WIDELY SCATTERED
DUE TO THAT AREA LYING TO THE NORTHWEST OF THE BETTER FORCING.
AFTER ABOUT MID-MORNING THE LOW LEVEL JET WILL SLIDE OFF TO OUR
EAST...WHILE THE AXIS OF THE INVERTED SURFACE TROUGH WILL GET
SUPPRESSED SOUTHEASTWARD IN RESPONSE TO STRONG CANADIAN HIGH
PRESSURE BUILDING SOUTHEASTWARD ACROSS ONTARIO PROVINCE AND THE
UPPER GREAT LAKES. THIS WILL RESULT IN ANY SHOWERS COMMENSURATELY
WINDING DOWN FROM NORTHWEST TO SOUTHEAST...ALLOWING FOR A RETURN TO
MAINLY DRY WEATHER BY LATE AFTERNOON IN MOST AREAS. THIS BEING
SAID...A GENERAL NORTHERLY/NORTHEASTERLY UPSLOPE FLOW WILL KEEP
MOSTLY CLOUDY SKIES INTACT ACROSS THE AREA FOR THE BULK OF THE
DAY...WITH JUST SOME LIMITED SUN POSSIBLE ACROSS NORTHERN SECTIONS
LATE.
KEY MESSAGE 2...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH MOST
OF THE UPCOMING WEEK, WITH A FEW SHOWERS POSSIBLE AT TIMES MIDWEEK.
THROUGH THE WORK WEEK THE BULK OF BROAD UPPER LEVEL TROUGHING OVER
EASTERN CANADA WILL SLOWLY DRIFT EASTWARD AND OUT TO SEA...WITH THE
SOUTHWESTERN EXTENT OF THIS TROUGH EVENTUALLY BREAKING OFF AND
EVOLVING INTO A MODEST CLOSED UPPER LOW OVER THE OHIO VALLEY/MID-
ATLANTIC STATES DURING THE MID-LATE WEEK PERIOD. MEANWHILE AT THE
SURFACE...A LARGE AREA OF COOL CANADIAN HIGH PRESSURE WILL SLOWLY
DRIFT FROM ONTARIO TO QUEBEC PROVINCES. THE PREVAILING NORTHEASTERLY
TO EASTERLY FLOW AROUND THE HIGH WILL KEEP A COOLER THAN NORMAL
AIRMASS INTACT ACROSS OUR REGION THROUGH THE MAJORITY OF THE
UPCOMING WEEK...WITH THE COOLEST DAYS COMING MONDAY-TUESDAY WHEN
HIGHS WILL RANGE FROM THE UPPER 50S TO LOWER 60S IN MOST AREAS...
WITH ONLY GRADUAL DAY-TO-DAY WARMING THEN FOLLOWING FOR THE REST OF
THE WEEK.
WITH RESPECT TO PRECIPITATION CHANCES...UNCERTAINTY PERSISTS WITH
RESPECT TO HOW FAR BACK NORTH INVERTED TROUGHING EXTENDS DURING THE
MIDWEEK PERIOD IN RESPONSE TO THE DEVELOPING CLOSED UPPER LOW.
DEPENDING UPON JUST HOW FAR NORTH THIS ULTIMATELY GETS...THERE COULD
BE A FEW SPOTTY SHOWERS ACROSS PORTIONS OF WESTERN NEW YORK TUESDAY
THROUGH THURSDAY...FOR WHICH CURRENT BLENDED GUIDANCE OF SLIGHT
CHANCE TO CHANCE POPS LOOKS REASONABLE.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
AN INVERTED TROUGH EXTENDING FROM THE OHIO VALLEY NORTHEAST ACROSS
NEW YORK STATE WILL GET SHUNTED SOUTHEASTWARD TODAY AND TONIGHT AS
STRONG CANADIAN HIGH PRESSURE BUILDS SOUTHEASTWARD ACROSS ONTARIO
PROVINCE. CONSEQUENTLY...SCATTERED TO NUMEROUS SHOWERS ALONG AND TO
THE SOUTH OF THIS BOUNDARY (MAINLY ALONG AN AXIS EXTENDING FROM THE
SOUTHERN TIER TO THE NORTH COUNTRY) DURING THE FIRST PART OF THIS
MORNING WILL WIND DOWN FROM NORTHWEST TO SOUTHEAST DURING THE REST
OF THE DAY...WITH DRY CONDITIONS THEN FOLLOWING FOR TONIGHT.
THE ABOVE BEING SAID...A DEVELOPING NORTH TO NORTHEASTERLY UPSLOPE
LOW LEVEL FLOW ON THE NORTH SIDE OF THE INVERTED TROUGH WILL STILL
LEAD TO CEILINGS FALLING INTO THE MVFR TO IFR RANGES THROUGH MID TO
LATE THIS MORNING...WITH SOME LIFR CEILINGS FOUND ACROSS THE
SOUTHERN TIER AND HIGHER TERRAIN OF THE INTERIOR FINGER LAKES.
FLIGHT CONDITIONS WILL THEN GRADUALLY IMPROVE TO VFR FROM NORTHWEST
TO SOUTHEAST THIS AFTERNOON AND EARLY THIS EVENING AS DRIER AIR
ATTENDANT TO THE BUILDING SURFACE RIDGE WORKS ACROSS OUR AREA AT THE
LOWER LEVELS. LATER ON TONIGHT...ANOTHER UPTICK IN LOW LEVEL
MOISTURE AND INCREASING UPSLOPE FLOW SHOULD THEN LEAD TO ANOTHER
PERIOD OF MVFR TO LOCALIZED IFR CEILINGS ACROSS WESTERN NEW YORK AND
ACROSS THE HIGHER TERRAIN OF THE NORTH COUNTRY.
OUTLOOK...
MONDAY...DRY WEATHER WITH IMPROVEMENT TO MAINLY VFR CEILINGS.
MONDAY NIGHT THROUGH THURSDAY...PERIODIC SCATTERED SHOWERS WITH MVFR
OR WORSE POSSIBLE.
MARINE
MODEST EASTERLY FLOW IN PLACE EARLY THIS MORNING WILL TURN MORE
NORTHEASTERLY AND FRESHEN A BIT TODAY. WHILE THIS WILL PRODUCE
INCREASINGLY CHOPPY CONDITIONS ALONG THE SOUTH SHORES OF THE LOWER
GREAT LAKES...CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY
CRITERIA.
THE NORTHEASTERLY FLOW WILL THEN INCREASE FURTHER BETWEEN LATER
TONIGHT AND EARLY MONDAY...WITH A FAIRLY BRISK FLOW THEN PERSISTING
THROUGH TUESDAY WHILE GRADUALLY VEERING MORE EASTERLY OVER TIME.
THIS WILL LIKELY LEAD TO AN EXTENDED PERIOD OF SCA-WORTHY CONDITIONS
ACROSS PORTIONS OF THE LOWER LAKES.
BUF WATCHES/WARNINGS/ADVISORIES
NY...NONE.
MARINE...NONE.
DISCUSSION...JJR
AVIATION...JASZKA/JJR
MARINE...JJR
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