Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 280637
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
237 AM EDT THU APR 28 2016

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL KEEP FAIR AND DRY WEATHER ACROSS THE
REGION THROUGH THE REST OF TONIGHT. SEVERAL WAVES OF LOW PRESSURE
WILL THEN RIPPLE EASTWARD ACROSS THE OHIO VALLEY AND MID ATLANTIC
STATES THURSDAY AND FRIDAY...BRINGING RENEWED SHOWER CHANCES TOWARDS
SOUTHERN PORTIONS OF THE FORECAST AREA. OTHERWISE TEMPERATURES WILL
REMAIN BELOW NORMAL THROUGH THE END OF THE WEEK...BEFORE CLIMBING
BACK TO AROUND AVERAGE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
QUIET WEATHER WILL PERSIST ACROSS THE ENTIRE FORECAST AREA THROUGH
THE REST OF TONIGHT AND INTO THE MORNING HOURS AS A RIDGE OF HIGH
PRESSURE EXTENDING FROM THE MAIN HIGH OVER NORTHERN MANITOBA TO THE
MID-ATLANTIC COAST WILL REMAIN IN PLACE. HOWEVER...EVEN THOUGH
SURFACE HIGH PRESSURE WILL KEEP CONDITIONS DRY THROUGH THE REST OF
THE NIGHT...HIGH CLOUDS ASSOCIATED WITH WARM ADVECTION ALOFT IN
ADVANCE OF A VERTICALLY STACKED LOW OVER THE MISSOURI VALLEY ARE
CURRENTLY OVERSPREADING WESTERN AND PORTIONS OF NORTH-CENTRAL NEW
YORK. THIS INCREASING CLOUD COVER IS RETARDING THE FALL OF
TEMPERATURES AT THIS TIME AND AS A RESULT HAVE BUMPED OVERNIGHT LOW
TEMPERATURES UP A FEW DEGREES WITH MANY AREAS OF WESTERN NEW YORK
ONLY FALLING INTO THE UPPER 30S. TEMPERATURES WILL RUN COOLER THE
FARTHER NORTH AND EAST ONE GOES ACROSS THE FORECAST AREA THANKS TO
LONGER AVAILABLE TIME FOR RADIATIONAL COOLING BEFORE CLOUD COVER
ARRIVES. LOOK FOR LOW TO MID 30S FROM THE GENESEE VALLEY EAST WITH
MID 20S ACROSS THE NORTH COUNTRY, WHERE SKIES SHOULD REMAIN CLEAR
THROUGH THE REST OF THE NIGHT.

THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL CONTINUE TO FILL ON
THURSDAY AS IT GETS SHEARED OUT ACROSS THE MIDWEST AND SOUTHERN
GREAT LAKES. AS THE PIECES OF THIS DISSIPATING LOW GET ADVECTED
ACROSS THE MIDWEST TO THE MID-ATLANTIC STATES...THEY WILL PRODUCE
ENOUGH WEAK LIFT ALOFT AND SURFACE CONVERGENCE TO GENERATE SHOWERS
ACROSS PENNSYLVANIA. BY THIS AFTERNOON THESE SHOWERS MAY EXTEND INTO
THE SOUTHERN TIER, THOUGH THE HIGHEST CHANCES WILL REMAIN NEAR THE
PENNSYLVANIA BORDER AS LOW-LEVEL MOISTURE WILL DIMINISH SHARPLY
AS ONE MOVES NORTH TOWARDS LAKE ONTARIO. IN ADDITION...STRONG
CONVERGENCE ALOFT NORTH OF THE THRUWAY SHOULD PRECLUDE SHOWERS FROM
EXTENDING NORTH OF THE SOUTHERN TIER. HOWEVER THIS SHOULD NOT
PREVENT MID AND HIGH CLOUDS FROM CONTINUING TO THICKEN AS THEY PRESS
NORTHWARDS ACROSS THE FORECAST AREA COURTESY OF THE INCREASING WARM
ADVECTION ALOFT. THE THICKENING CLOUDS AND COOL NORTHEASTERLY
SURFACE FLOW THAT WILL REMAIN IN PLACE WILL KEEP TEMPERATURES RATHER
COOL FOR LATE APRIL WITH HIGHS RUNNING IN THE LOW TO MID 50S...WITH
WARMEST AREAS IN THE NORTH COUNTRY WHERE FLOW WILL BE
OFFSHORE/DOWNSLOPING AND HIGH CLOUDS THINNEST.

EXPECT LITTLE CHANGE IN OVERALL FORECAST FOR THURSDAY NIGHT AS SMALL
PIECES OF UPPER LEVEL ENERGY WILL CONTINUE TO RIPPLE BY ALONG THE
NY/PA BORDER AND A WEAK INVERTED SURFACE TROUGH APPROACHES WESTERN
NEW YORK. THIS WILL SERVE TO CONTINUE THE CHANCE FOR A FEW SHOWERS
ACROSS THE SOUTHERN TIER WITH DRY CONDITIONS EXPECTED ELSEWHERE.
LINGERING CLOUDS AND WARMER TEMPERATURES ALOFT WILL YIELD A SLIGHTLY
WARMER NIGHT WITH LOWS RANGING FROM THE UPPER 30S IN WESTERN NEW
YORK TO THE LOWER 30S IN THE NORTH COUNTRY.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AN INITIAL WING OF WARM ADVECTION WILL CONTINUE TO MOVE SLOWLY ENE
ACROSS PORTIONS OF THE AREA THURSDAY NIGHT WHILE AN ASSOCIATED MID
LEVEL WAVE MOVES EAST ACROSS PA. ISENTROPIC UPGLIDE IN THE WARM
ADVECTION REGIME AND WEAK DPVA AHEAD OF THE MID LEVEL WAVE WILL
SUPPORT AT LEAST A FEW SHOWERS THURSDAY EVENING. MODEL GUIDANCE
CONTINUES TO SHOW SOME VARIABILITY WITH THE NORTHERN EXTENT OF THE
RAIN SHIELD...AS THE LATEST 12Z GUIDANCE TRENDED A LITTLE NORTH WITH
RAIN REACHING A BUFFALO TO BATAVIA TO CANANDAIGUA LINE. WHILE A FEW
SHOWERS CANNOT BE RULED OUT THAT FAR NORTH...EXTENSIVE LOW LEVEL DRY
AIR ON THE NORTHERN EDGE OF THE SYSTEM SHOULD KEEP THE MAJORITY OF
THE RAIN SOUTH OF THE THRUWAY WITH THE GREATER AMOUNTS FOUND CLOSER
TO THE PA STATE LINE. LOWS ACROSS WESTERN AND CENTRAL NY WILL
GENERALLY BE IN THE UPPER 30S...WITH LOWER 30S ACROSS THE NORTH
COUNTRY WHERE SKIES WILL REMAIN CLEAR.

ON FRIDAY ANOTHER SOMEWHAT STRONGER MID LEVEL WAVE WILL MOVE ACROSS
THE UPPER OHIO VALLEY AND INTO PA...WITH A WEAK SURFACE LOW MOVING
ACROSS OHIO INTO SOUTHERN PA. AGAIN THERE ARE SOME MODEL DIFFERENCES
WITH THIS SYSTEM...AS THE 12Z GFS IS ABOUT 6 HOURS FASTER THAN THE
NAM AND CANADIAN GEM. THE MAJORITY OF THE RAIN WITH THIS SYSTEM WILL
SPREAD ACROSS THE SOUTHERN TIER...ALTHOUGH THE HEAVIER RAIN AMOUNTS
WILL LIKELY REMAIN ON THE PA SIDE OF THE BORDER. THE NORTHERN EDGE OF
THE RAIN WILL AGAIN APPROACH THE NYS THRUWAY CORRIDOR FROM BUFFALO TO
ROCHESTER...WHILE THE COUNTRY WILL LIKELY REMAIN DRY. THE ADDITIONAL
CLOUDS AND SHOWERS WILL HOLD TEMPERATURES DOWN...WITH HIGHS IN THE
MID 50S FROM THE NIAGARA FRONTIER TO GENESEE VALLEY...AND LOWER 50S
ACROSS THE SOUTHERN TIER. THE NORTH COUNTRY WILL SEE MUCH MORE
SUNSHINE...WHICH WILL BOOST TEMPERATURES INTO THE LOWER 60S DESPITE
COOLER AIR ALOFT.

FRIDAY NIGHT THE WAVE OF LOW PRESSURE WEAKENS AND MOVES OFF THE MID
ATLANTIC COAST...WITH ANY SHOWERS ACROSS THE SOUTHERN TIER AND
FINGER LAKES ENDING DURING THE EVENING. EXPECT SOME CLEARING
OVERNIGHT AS HIGH PRESSURE BUILDS BACK INTO THE GREAT LAKES AND A
DRIER AIRMASS MOVES INTO THE REGION.

A WEAK AREA OF HIGH PRESSURE WILL THEN REMAIN IN PLACE THROUGH
SATURDAY WITH A RETURN TO SUNSHINE AREAWIDE AND SEASONABLE
TEMPERATURES WITH HIGHS IN THE LOWER 60S. NORTHEAST WINDS WILL KEEP
THE SOUTH SHORE OF LAKE ONTARIO MUCH COOLER.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY... A WAVE WILL EJECT OUT OF THE MEAN TROUGH ACROSS THE
CENTRAL CONUS... THROUGH THE OHIO VALLEY... AND MERGING WITH THE
MEAN TROUGH IN PLACE FROM THE HUDSON BAY ACROSS THE NORTH EAST
CONUS. THE RESULT WILL BE A PERIOD OF UNSETTLED WEATHER WITH
CHANCES FOR RAIN SHOWERS AND TEMPERATURES NEAR SEASONAL VALUES FOR
THIS TIME OF YEAR. GREATEST PRECIPITATION CHANCES WILL COME DURING
THE DAY SUNDAY INTO SUNDAY NIGHT... WITH PLENTY IN QUESTION IN
TERMS OF INTENSITY/COVERAGE ACROSS THE REGION DEPENDING ON THE
TRACK OF THE EJECTING SHORTWAVE. THE MEAN TROUGH NEAR THE
NORTHEAST WILL REMAIN IN PLACE FOR THE START OF NEXT WEEK... WITH
MORE CHANCES FOR RAIN SHOWERS AS NORTHERN STREAM SHORTWAVES PIVOT
AROUND THE THROUGH IN THE WEST/NORTHWEST FLOW ALOFT. TEMPERATURES
WILL AGAIN REMAIN NEAR SEASONAL NORMALS INTO THE START OF NEXT
WEEK.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE EXTENDING FROM NORTHERN MANITOBA TO THE MID-ATLANTIC
COAST WILL KEEP VFR CONDITIONS IN PLACE ACROSS THE FORECAST AREA
THROUGH THE REST OF THE NIGHT. ON THURSDAY A WEAKENING AREA OF LOW
PRESSURE WILL SLIDE BY TO OUR SOUTH ACROSS PENNSYLVANIA. THIS SYSTEM
WILL BRING A CHANCE OF SHOWERS...MAINLY TO THE SOUTHERN TIER WITH
HIGHEST CHANCES BEING RIGHT ALONG THE PA BORDER.

OTHERWISE EXPECT VFR CONDITIONS TO PERSIST THROUGH THE DAY EVEN AS
HIGH CLOUDS THICKEN AND LOWER INTO A MIDDLE CLOUD DECK BETWEEN 7-
10KFT SOUTH OF LAKE ONTARIO. CIGS ARE EXPECTED TO LOWER INTO MVFR
RANGE ACROSS HIGHER ELEVATIONS OF THE SOUTHERN TIER WEDNESDAY NIGHT
AS ANOTHER WAVE OF LOW PRESSURE PASSES BY AND MOISTURE DEEPENS
SOMEWHAT. THIS WILL ALSO SERVE TO KEEP THE CHANCE OF SHOWERS IN
THROUGH WEDNESDAY NIGHT ACROSS THE SOUTHERN TIER WITH DRY CONDITIONS
AND GENERAL NORTHEASTERLY FLOW EXPECTED ELSEWHERE.

OUTLOOK...
THURSDAY NIGHT AND FRIDAY...VFR...WITH SCATTERED TO NUMEROUS
SHOWERS/POSSIBLE MVFR SOUTH OF LAKE ONTARIO.
SATURDAY...VFR.
SUNDAY AND MONDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN DRAPED ACROSS THE LOWER LAKES REGION
THROUGH TONIGHT...AND WILL KEEP LIGHT TO MODERATE NORTHWESTERLY
TO NORTHEASTERLY WINDS IN PLACE...ALONG WITH CORRESPONDINGLY
MINIMAL WAVES.

THURSDAY AND FRIDAY...LOW PRESSURE SLOWLY TRACKING ACROSS THE
OHIO VALLEY WILL HELP INDUCE SOME STRENGTHENING OF THE GENERAL
NORTHEASTERLY FLOW ACROSS THE LOWER LAKES. WHILE CONDITIONS
SHOULD REMAIN BELOW ADVISORY LEVELS THROUGH THURSDAY...A PERIOD
OF ADVISORY-WORTHY WINDS AND WAVES APPEARS POSSIBLE ALONG THE
SOUTH SHORES OF BOTH LAKES THURSDAY NIGHT INTO FRIDAY.

&&

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

&&

$$

SYNOPSIS...JJR/WOOD
NEAR TERM...WOOD
SHORT TERM...HITCHCOCK
LONG TERM...CHURCH
AVIATION...WOOD
MARINE...JJR



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