Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 051046
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
646 AM EDT THU MAY 5 2016

.SYNOPSIS...
A DEEP UPPER LEVEL TROUGH WILL REMAIN PARKED OVER THE REGION
THROUGH THE END OF THE WEEK. AS A RESULT...WE CAN EXPECT SOMEWHAT
UNSETTLED WEATHER TO PERSIST THROUGH THE NEXT COUPLE OF DAYS...
THOUGH TEMPERATURES WILL REMAIN FAIRLY CLOSE TO NORMAL LEVELS
FOR EARLY MAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
HAVE RECENTLY ADJUSTED THE FORECAST TO ACCOUNT FOR THE LOCALIZED
AREAS OF FOG THAT HAVE DEVELOPED OVER THE NIAGARA FRONTIER OVER
THE PAST HOUR OR TWO...WHICH SHOULD MIX OUT OVER THE NEXT FEW
HOURS WITH RENEWED DAYTIME HEATING.

OTHERWISE DURING THE COURSE OF TODAY...DEEP UPPER LEVEL TROUGHING
WILL REMAIN IN PLACE OVERHEAD...WITH AN EMBEDDED CLOSED UPPER LOW
SLIDING FROM THE LOWER OHIO VALLEY INTO THE CAROLINAS. MEANWHILE
AT THE SURFACE...A COASTAL LOW WILL LIFT NORTHEASTWARD OFFSHORE
OF THE EASTERN SEABOARD...WHILE A LINGERING INVERTED TROUGH OVER
FAR WESTERN NEW YORK SLOWLY DECAYS AND RECEDES SOUTHWARD.

UNDER THIS PATTERN...THE VAST MAJORITY OF ANY DEEP/LARGE-SCALE
FORCING WILL BE SITUATED WELL TO THE SOUTH AND EAST OF OUR REGION
TODAY...WITH JUST SOME LINGERING WEAKER LOW-LEVEL CONVERGENCE FOUND
IN THE VICINITY OF THE SURFACE TROUGH. IN CONJUNCTION WITH LINGERING
MOISTURE...THIS WILL HELP TO GENERATE SOME SCATTERED SHOWERS AT
TIMES...WITH THE GREATEST COVERAGE OF THIS ACTIVITY AGAIN COMING
THIS AFTERNOON IN CONJUNCTION WITH PEAK DIURNAL HEATING/ATMOSPHERIC
DESTABILIZATION. LOCATION-WISE...EXPECT A FEW SHOWERS TO BE POSSIBLE
JUST ABOUT ANYWHERE ALONG THE SURFACE TROUGH THROUGH EARLY THIS
MORNING...WITH THE ACTIVITY THEN LARGELY RETREATING TO INTERIOR
PORTIONS OF THE SOUTHERN TIER BY THIS AFTERNOON...CLOSER TO THE
FADING SURFACE BOUNDARY AND AWAY FROM THE STABILIZING NORTHEASTERLY
FLOW OFF LAKES ERIE AND ONTARIO. HAVE RETAINED THE CHANCE POPS FROM
CONTINUITY TO COVER THIS ACTIVITY...WITH THE HIGHEST PROBABILITIES
/HIGH CHANCE/ INDICATED THIS AFTERNOON...WHEN THERE MAY AGAIN BE
JUST ENOUGH INSTABILITY TO POP A THUNDERSTORM ACROSS THE SOUTHERN
TIER.

ASIDE FROM THE ABOVE...EXPECT A MAINLY DRY DAY...WITH FAIRLY
WIDESPREAD EARLY MORNING CLOUD COVER EVENTUALLY GIVING WAY TO
SOME PARTIAL SUNSHINE ACROSS THE LAKE PLAINS. WITH 850 MB TEMPS
RUNNING BETWEEN +2C AND +4C...EXPECT HIGHS TO PRIMARILY RANGE FROM
THE UPPER 50S ACROSS THE HIGHER TERRAIN TO THE LOWER 60S ACROSS THE
LOWER ELEVATIONS...THOUGH AREAS ALONG THE SOUTH SHORES OF BOTH
LAKES WILL AGAIN BE COOLER DUE TO THE PREVAILING NORTHEASTERLY
LOW-LEVEL FLOW. THIS WILL ESPECIALLY BE THE CASE RIGHT ALONG THE
SOUTH SHORE OF LAKE ONTARIO...WHERE HIGHS WILL AGAIN LIKELY
STRUGGLE TO REACH ABOVE THE MID TO UPPER 40S.

TONIGHT...THE CORE OF THE CLOSED LOW WILL SLIDE EAST TO THE
CAROLINA COASTLINE...WHILE SPURRING THE DEVELOPMENT OF ANOTHER
MODEST SURFACE LOW OFF THE DELMARVA COAST. THE BULK OF THE
LARGER-SCALE FORCING WITH THESE FEATURES WILL THUS AGAIN REMAIN
WELL TO OUR SOUTH AND EAST...WITH JUST SOME LIMITED SHORTWAVE
ENERGY CIRCULATING AROUND THE NORTHERN EDGE OF THE CLOSED LOW
AND BRUSHING SOUTHERN/CENTRAL NEW YORK STATE AT TIMES. IN
CONJUNCTION WITH THE LOSS OF HEATING...THIS SHOULD TRANSLATE
INTO A MAINLY DRY NIGHT FOR OUR REGION...WITH JUST A LOW CHANCE
FOR SOME ADDITIONAL SHOWERS FOUND ACROSS THE SOUTHERN TIER AND
INTERIOR SECTIONS OF THE FINGER LAKES. OTHERWISE EXPECT PARTLY
TO MOSTLY CLOUDY SKIES TO PREVAIL...WITH OVERNIGHT LOWS MAINLY
IN THE MID TO UPPER 40S.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
A TYPICAL SPRINGTIME...HIGHLY AMPLIFIED PATTERN WILL BE FOUND ACROSS
THE COUNTRY TO OPEN THIS PERIOD. LIKE A PAIR OF HEADLIGHTS STARING AT
YOU...DEEP TWIN CLOSED LOWS WILL BE FOUND ALONG EACH COAST WHILE
RIDGING WILL BE FOUND ACROSS THE NATIONS MID SECTION. THIS PATTERN
WILL BREAK DOWN DURING THE COURSE OF THE WEEKEND THOUGH...AS ENERGY
SPILLING OVER THE MACKENZIE MOUNTAINS IN THE YUKON WILL DIVE
SOUTHEAST ACROSS THE CANADIAN PRAIRIES TO THE GREAT LAKES BY SUNDAY.
THIS WILL DISRUPT THE UPPER LEVEL PATTERN OVER THE LOWER 48 BY
KICKING OUT THE ATLANTIC COAST CLOSED LOW WHILE ESTABLISHING A NEW
CLOSED CIRCULATION OVER EASTERN CANADA. THE COLD FRONT THAT WILL
LEAD THIS PATTERN CHANGE WILL END OUR BRIEF TASTE OF EARLY SUMMER
WEATHER SATURDAY NIGHT BY PLUNGING OUR REGION BACK TO A REGIME OF
BELOW NORMAL TEMPERATURES FOR SUNDAY AND MONDAY. THE DETAILS...

A BROAD CLOSED LOW CENTERED OVER NORTH CAROLINA FRIDAY MORNING WILL
SLOWLY DRIFT NORTH ACROSS THE DELMARVA PENINSULA DURING THE MIDDAY
AND AFTERNOON...WHILE SPOKES OF ENERGY AND PLENTY OF ATLANTIC BASED
MOISTURE WILL ROTATE BACK ACROSS NEW YORK STATE WITHIN THE RESULTING
DEEP EASTERLY FLOW. THIS WILL PROMOTE SCATTERED SHOWERS ACROSS MUCH
OF THE REGION AS WE WORK OUR WAY THROUGH THE DAY...ESPECIALLY OVER
THE FINGER LAKES REGION WHERE POPS HAVE BEEN RAISED TO LIKELY. AS
ONE WOULD EXPECT IN A MARINE BASED ERLY FLOW...THERE WILL NOT BE
ENOUGH INSTABILITY TO ADD ANY THUNDER TO THIS SHOWER ACTIVITY. ODDLY
ENOUGH...THE EASTERLY FLOW WILL ALSO INCLUDE SOME WARM ADVECTION
WITH H85 TEMPS NUDGING UP TO ARND 6C. DESPITE THE CLOUD COVER...THIS
SHOULD SUPPORT FAIRLY WIDESPREAD TEMPERATURES IN THE 60S FOR THE
AFTERNOON...ESPECIALLY ACROSS THE NORTH COUNTRY WHERE READINGS COULD
MAKE IT INTO THE UPPER 60S. THE EXCEPTION TO THE MILDER AIR WILL BE
ACROSS THE HIGHER TERRAIN OF THE SRN TIER.

THE CLOSED LOW WILL BRIEFLY STALL OVER EASTERN PENNSYLVANIA FRIDAY
NIGHT...WHILE FAIRLY DEEP ATLANTIC MOISTURE WILL REMAIN IN PLACE
OVER MUCH OF OUR FORECAST AREA. THIS WILL KEEP AT LEAST THE RISK FOR
SCATTERED SHOWERS IN PLACE...ESPECIALLY EARLY WHEN A LITTLE LEFTOVER
DIURNAL INSTABILITY WILL ASSIST EMBEDDED SHORTWAVES IN THE EASTERLY
FLOW.

ON SATURDAY...THE PERSISTENT UPPER LOW WILL GRADUALLY FILL WHILE
WEAK RIDGING WILL PUSH ACROSS THE LOWER GREAT LAKES. THIS...IN
COMBINATION WITH A LITTLE DRYING IN THE MID LEVELS...SHOULD ENABLE
PARTIAL SUNSHINE TO RETURN TO MUCH OF THE FORECAST AREA WITH MAINLY
DRY WEATHER ANTICIPATED. THE EXCEPTION COULD BE OVER THE FAR WESTERN
COUNTIES WHERE THE EFFECTS OF AN APPROACHING COLD FRONT COULD BE
EXPERIENCED BY DINNER TIME. OTHERWISE...SATURDAY SHOULD BE A FAIRLY
NICE DAY WITH A SURGE OF 8-10C H85 AIR AHEAD OF THE FRONT
ENCOURAGING TEMPERATURES TO PEAK IN THE 70S. THE GENESEE VALLEY AND
SOME OF THE SRN TIER VALLEYS COULD BE IN LINE FOR READINGS IN THE
MID AND EVEN UPPER 70S...PENDING THE AMOUNT OF SUN WE RECEIVE DURING
THE MIDDAY AND AFTERNOON. GIVEN THE WEAK SYNOPTIC FLOW...WEAK LAKE
BREEZES WILL KEEP AREAS WITHIN 5 MILES OR SO OF THE LAKES IN THE 50S
AND 60S.

THE COLD FRONT WILL MAKE ITS WAY ACROSS WESTERN AND NORTH CENTRAL
NEW YORK SATURDAY NIGHT. GIVEN THE WAVY NATURE OF THE FRONT (AS PER
THE PAST SEVERAL RUNS OF THE GFS AND ECMWF) AND SIGNIFICANT HGT
FALLS...HAVE RAISED POPS TO CATEGORICAL REGIONWIDE FOR SHOWERS AND
POSSIBLE THUNDERSTORMS. QPF FROM THIS FRONTAL PASSAGE IS FORECAST TO
RANGE FROM A QUARTER TO AT MOST A HALF INCH.

IN THE WAKE OF THE FRONT...IT WILL BE BREEZY AND NOTABLY COOLER ON
SUNDAY. H85 TEMPS ARE EXPECTED TO AVERAGE WITHIN A DEGREE OR SO OF
ZERO C...SO AFTERNOON TEMPERATURES ARE NOT EXPECTED TO CLIMB OUT OF
THE 50S. WHILE A BRIEF SHOWER CANNOT BE RULED OUT WITHIN THE CHILLY
CYCLONIC FLOW...SIGNIFICANT DRYING THE MID LEVELS AND RIDGING IN THE
LOW LEVELS SHOULD PRECLUDE THE DEVELOPMENT OF ANY ORGANIZED/
WIDESPREAD SHOWERS.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
WHILE CONFIDENCE IN THE LOW LEVEL FEATURES WILL BE LOWER THAN NORMAL
DURING THIS PERIOD...CONSISTENCY BETWEEN THE GEFS AND ECMWF
ENSEMBLES WITH THE OVERLYING JET LEVEL PATTERN WILL SUPPORT
RELATIVELY HIGH CONFIDENCE WITH THE TEMPERATURE TREND. THIS WILL
INCLUDE NEAR TO ABOVE NORMAL MERCURY READINGS.

RIDGING OVER THE LOWER GREAT LAKES ON MONDAY WILL SUPPLY OUR
FORECAST AREA WITH FINE WEATHER...AS AMPLE SUNSHINE WILL HELP TO
SEND AFTERNOON TEMPERATURES INTO THE LOW-MID 60S FOR MOST AREAS.

THE RIDGE IS FORECAST TO FLATTEN OVER THE REGION MONDAY NIGHT WITH
FAIRLY STRONG WARM ADVECTION BECOMING ESTABLISHED. THIS COULD SET
THE STAGE FOR SOME SHOWERS MONDAY NIGHT...ALTHOUGH A HIGHER CHANCE
FOR PCPN WILL COME ON TUESDAY WHEN THE A TROUGH WILL DIG ACROSS
QUEBEC AND SOUTHERN ONTARIO.

AS THE TROUGH PUSHES EAST ACROSS THE ST LAWRENCE VALLEY LATE TUESDAY
NIGHT AND WEDNESDAY...LOW LEVEL RIDGING SHOULD ONCE AGAIN TAKE HOLD
ACROSS THE LOWER GREAT LAKES TO PROMOTE FAIR WEATHER.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
IN SPITE OF FAIRLY PERSISTENT MID AND HIGH CLOUD COVER...SOME
LOWER STRATUS/FOG DID ACTUALLY MANAGE TO DEVELOP OVER THE PAST
FEW HOURS IN THE VICINITY OF KBUF/KIAG...AND IS CURRENTLY
PRODUCING IFR TO LIFR CONDITIONS AT THESE TWO TERMINALS.

DURING THE COURSE OF TODAY...WHATEVER LOWER STRATUS/FOG THAT
DEVELOPED IN THE PREDAWN HOURS SHOULD MIX OUT BY MID TO LATE
MORNING WITH RENEWED DIURNAL HEATING. THE DAYTIME HEATING WILL
ALSO LEAD TO THE DEVELOPMENT OF SOME ADDITIONAL DIURNALLY-DRIVEN
SCATTERED SHOWERS AND POSSIBLY EVEN A THUNDERSTORM ACROSS THE
SOUTHERN TIER DURING THE AFTERNOON...ANY OF WHICH COULD PRODUCE
SOME BRIEF/LOCALIZED REDUCTIONS TO MVFR. OUTSIDE OF THE ABOVE...
GENERAL VFR CONDITIONS SHOULD PREVAIL.

TONIGHT...EXPECT GENERAL VFR CONDITIONS TO PREVAIL...WITH JUST SOME
LINGERING SCATTERED SHOWERS/SPOTTY MVFR FOUND ACROSS THE SOUTHERN
TIER AND INTERIOR PORTIONS OF THE FINGER LAKES.

OUTLOOK...
FRIDAY...VFR/MVFR WITH SCATTERED TO NUMEROUS SHOWERS...WITH THE
GREATEST AREAL COVERAGE EXPECTED ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER AND FINGER LAKES.
SATURDAY...VFR.
SATURDAY NIGHT...SHOWERS WITH A CHANCE OF THUNDERSTORMS.
SUNDAY...MAINLY VFR WITH A CHANCE OF MORNING SHOWERS EAST OF KROC/KDSV.
MONDAY...VFR.

&&

.MARINE...
THE REMAINDER OF THE WEEK WILL FEATURE A RELATIVELY WEAK PRESSURE
GRADIENT ACROSS THE LOWER LAKES REGION. THIS WILL RESULT IN LIGHT
TO MODEST WINDS PREDOMINATING...ALONG WITH CORRESPONDINGLY MINIMAL
WAVES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR



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