Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 280230
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1030 PM EDT WED APR 27 2016

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

&&

.NEAR TERM /THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO PROVINCE
WILL REMAIN RIDGED ACROSS WESTERN AND NORTH CENTRAL NEW YORK
THROUGH TONIGHT. THIS FEATURE WILL MAINTAIN FAIR AND DRY WEATHER
ACROSS OUR REGION THROUGH TONIGHT...WITH PREDOMINANTLY CLEAR SKIES
MERELY GIVING WAY TO SOME INCREASING CIRRUS ACROSS THE SOUTHERN
TIER OVERNIGHT AS SOME WARM AIR ADVECTION BEGINS DEVELOPING ALOFT.
WITH PLENTY OF COOL DRY CANADIAN AIR REMAINING IN PLACE ALONG WITH
LIGHTENING WINDS...THE MAINLY CLEAR SKIES WILL AGAIN ALLOW FOR
EXCELLENT RADIATIONAL COOLING TONIGHT...WITH OVERNIGHT LOWS
RANGING FROM THE MID 20S ACROSS THE NORTH COUNTRY TO THE UPPER 20S
AND LOWER 30S ACROSS MOST AREAS SOUTH OF LAKE ONTARIO. ONLY THE
IMMEDIATE SOUTHERN LAKESHORES OF LAKES ERIE AND ONTARIO WILL AVOID
FREEZING TEMPS...WITH TEMPS BOTTOMING OUT IN THE MID 30S THERE.

ON THURSDAY...THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE WILL
SLIDE NORTHEASTWARD INTO QUEBEC PROVINCE AND NEW ENGLAND. MEANWHILE...
A WEAKENING PACIFIC-BASED UPPER LOW WILL MEANDER ITS WAY ACROSS THE
UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES...WITH ITS ATTENDANT
MODEST SURFACE WAVE GRADUALLY TRACKING UP THE OHIO VALLEY. THIS
LATTER FEATURE WILL SPREAD INCREASING/THICKENING CLOUDS ACROSS
AREAS SOUTH OF LAKE ONTARIO DURING THE COURSE OF THE DAY...WITH THE
12Z GUIDANCE UNIVERSALLY COMING INTO BETTER AGREEMENT THAT AVAILABLE
LIFT AND MOISTURE WILL BOTH BECOME SUFFICIENT TO SUPPORT SHOWER
CHANCES ACROSS AREAS ALONG AND SOUTH OF A ROUGH BUFFALO-BATAVIA-GENEVA
LINE DURING THE LATE MORNING AND AFTERNOON HOURS.

THE GREATEST POTENTIAL FOR SHOWERS ON THURSDAY WILL BE ACROSS THE
SOUTHERN TIER...WHICH WILL BE IN CLOSEST PROXIMITY TO THIS NEXT SYSTEM
AND WHERE SOME LOW LIKELY POPS WILL BE IN PLAY. NORTH OF THIS...PRECIP
CHANCES WILL SHARPLY DECREASE TO LOW CHANCE ALONG THE NYS THRUWAY
CORRIDOR...TO BELOW SLIGHT CHANCE ALONG THE SOUTH SHORE OF LAKE ONTARIO...
AND TO NIL ACROSS THE EASTERN LAKE ONTARIO REGION...WHERE DRY WEATHER
AND MOSTLY SUNNY SKIES WILL CONTINUE TO PREVAIL RIGHT THROUGH THE DAY.
AS FOR TEMPS...THE INCREASING CLOUD COVER/PRECIP CHANCES AND COOL EAST-
NORTHEASTERLY FLOW WILL KEEP HIGHS PREDOMINANTLY CONFINED TO THE UPPER
40S AND LOWER 50S SOUTH OF LAKE ONTARIO...WITH COOLER READINGS THAN
THESE AGAIN FOUND ALONG THE SOUTH SHORE OF LAKE ONTARIO. MEANWHILE
ACROSS THE NORTH COUNTRY...THE MUCH SUNNIER CONDITIONS WILL ALLOW FOR
HIGHS IN THE LOWER TO MIDDLE 50S.

&&

.SHORT TERM /THURSDAY NIGHT 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 /03Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO PROVINCE WILL
REMAIN ANCHORED ACROSS OUR REGION THROUGH TONIGHT...AND WILL
PROVIDE OUR REGION WITH CONTINUED FAIR DRY WEATHER AND HIGH-END
VFR CONDITIONS.

ON THURSDAY...THE AXIS OF THE SURFACE RIDGE WILL SLIDE NORTHEASTWARD
INTO QUEBEC PROVINCE AND NEW ENGLAND...WHILE A MODEST WAVE OF LOW
PRESSURE GRADUALLY TRACKS UP THE OHIO VALLEY. THIS LATTER FEATURE
WILL SPREAD INCREASING/THICKENING CLOUDS ACROSS AREAS SOUTH OF LAKE
ONTARIO DURING THE COURSE OF THE DAY...WITH INCREASING SHOWER CHANCES
SPREADING ACROSS AREAS ALONG AND SOUTH OF A ROUGH BUFFALO-BATAVIA-
GENEVA LINE DURING THE LATE MORNING AND AFTERNOON HOURS. GENERAL VFR
CONDITIONS WITH GRADUALLY LOWERING CIGS SOUTH OF LAKE ONTARIO SHOULD
PREVAIL THROUGH 18Z...BEFORE CONDITIONS LOWER TO MVFR/IFR ACROSS THE
SOUTHERN TIER BETWEEN 18Z THURSDAY AND 00Z FRIDAY.

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.

&&

.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
NEAR TERM...JJR/RSH
SHORT TERM...HITCHCOCK
LONG TERM...CHURCH
AVIATION...JJR/RSH
MARINE...JJR



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