Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 062054
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
454 PM EDT FRI MAY 6 2016

.SYNOPSIS...
AN UPPER LEVEL LOW ACROSS THE MID ATLANTIC STATES WILL WEAKEN AND
SLIDE OFF THE EASTERN SEABOARD ON SATURDAY. THIS SYSTEM WILL BRING
A CHANCE FOR SOME SHOWERS ACROSS THE REGION TONIGHT...BEFORE
DRIER WEATHER RETURNS FOR SATURDAY. A COLD FRONT WILL THEN CROSS
THE REGION SATURDAY NIGHT ALONG WITH ANOTHER ROUND OF SHOWERS AND
POSSIBLY SOME THUNDERSTORMS...FOLLOWED BY COOLER AIR SUNDAY AND
MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
LOW AND MID LEVEL CLOUDS WILL CONTINUE TO INCREASE LATE THIS
AFTERNOON...ALONG WITH SOME LIGHT SHOWERS ACROSS THE FINGER
LAKES...NORTH COUNTRY AND SOUTHERN TIER.

THE FEATURE RESPONSIBLE FOR THE CLOUDS AND SHOWERS IS AN UPPER
LEVEL LOW CURRENTLY CENTERED ALONG THE MID- ATLANTIC COAST WHICH
WILL SLOWLY MEANDER NORTH AND EAST THIS EVENING. AS THE UPPER LOW
CONTINUES TO DRIFT SLIGHTLY TOWARD OUR REGION...MOISTURE WILL
INCREASE. THIS WILL BE AIDED BY A DEVELOPING LOW/MID LEVEL JET
WITH ORIGINS OVER THE WESTERN ATLANTIC AND A MID LEVEL VORTICITY
LOBE ROTATING AROUND THE APPROACHING UPPER LOW.

CLOUDS AND SHOWERS WILL CONTINUE TO SPREAD WESTWARD ACROSS OUR
REGION TONIGHT...WITH SHOWERS INCREASING UNTIL THE UPPER LEVEL
LOW BEGINS TO PULL AWAY FROM THE REGION LATE TONIGHT.

EXPECT SATURDAY TO START OF WITH SOME SUNSHINE IN WESTERN
AREAS...ALONG WITH PLEASANTLY WARM TEMPERATURES. CLOUDS WILL THEN
INCREASE AGAIN AHEAD OF AN APPROACHING COLD FRONT. CHANCES FOR SHOWERS
AND A FEW THUNDERSTORMS WILL INCREASE SATURDAY AFTERNOON. TEMPERATURE
WISE...LOOK FOR HIGHS TO PEAK IN THE UPPER 60S TO LOW 70S.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
SATURDAY NIGHT A COLD FRONT WILL CONTINUE TO PUSH ACROSS THE
CWA...WITH A LINE OF SHOWERS ALONG AND AHEAD OF THE FEATURE.
GREATEST INSTABILITY OF MUCAPES OF 200 TO 400 J/KG WILL BE FOUND
NEAR THE NYS/PA STATE LINE AND WILL CONTINUE TO MENTION THUNDER NEAR
LAKE ERIE AND THEN ALONG THE STATE LINE...WITH JUST SHOWERS
ELSEWHERE. IT WILL REMAIN MILD AHEAD OF THE FRONT...WITH 50S AND
LOWER 60S LINGERING INTO THE EVENING HOURS AHEAD OF THE FRONT. THEN
POST FRONT TEMPERATURES WILL DROP BACK INTO THE LOWER 40S.

SUNDAY WILL REMAIN COOL AS AN UPPER LEVEL LOW AND ITS ASSOCIATED
COOL POOL DROP ACROSS THE REGION. WHILE SUNDAY MORNING MAY START
MOSTLY SUNNY...ESPECIALLY IN THE WEST...BOTH THE 12Z GFS AND 12Z
ECMWF DISPLAY ADDITIONAL MOISTURE PUSHED SOUTHWARD WITH THE UPPER
LEVEL LOW...AND THE CYCLONIC FLOW AND COOL POOL ALOFT COMBINED WITH
STEEP 800-1000 HPA LAPSE RATES MAY BE ENOUGH TO TRIGGER INSTABILITY
SHOWERS IN THE AFTERNOON. WILL CONTINUE THE CHANCE FOR SUCH SHOWERS
SUNDAY AFTERNOON WITH THIS LATE MORNING UPDATE...WITH GREATEST
CHANCES FOR SUCH ACTIVITY ACROSS THE NORTHERN 2/3RDS OF THE CWA
WHERE MOISTURE WILL BE DEEPEST.

SUNDAY WILL ALSO BE CHILLY FOR EARLY MAY STANDARDS. TEMPERATURES AT
850 HPA OF ONLY A FEW DEGREES CELSIUS...AND A THICKENING AFTERNOON
CLOUD COVER WILL HOLD AFTERNOON HIGHS IN THE 50S...SOME 10F DEGREES
BELOW NORMAL.

SUNDAY NIGHT ANY SHOWER ACTIVITY WILL QUICKLY END WITH THE LOSS OF
DAYTIME HEATING...WEAKENING OF THE LOW LEVEL LAPSE RATES AND THE
AXIS OF THE UPPER LEVEL LOW NOW TO OUR EAST. AS HIGH PRESSURE AT
THE SURFACE EDGES EASTWARD TOWARDS THE EASTERN GREAT LAKES SKIES WILL
BEGIN TO CLEAR. WILL A COOL START...OVERNIGHT LOWS WILL DROP BACK
INTO THE MID 30S TO LOWER 40S.

ON MONDAY THIS HIGH PRESSURE WILL BRING FAIR WEATHER WITH
TEMPERATURES A BIT WARMER THAN SUNDAY WITH TEMPERATURES RETURNING TO
THE UPPER 50S TO UPPER 60S. COOLEST AREAS WILL BE EAST AND NORTH
EAST OF LAKE ERIE WHERE SOUTHWESTERLY WINDS WILL MAINTAIN COOLER 50S
ALONG THE LAKE SHORE AND INLAND ACROSS BUFFALO METRO AREA...AND ALSO
THE NORTH COUNTRY WILL LIKELY REMAIN IN THE UPPER 50S. WARMEST
REGIONS WILL BE THE VALLEYS OF THE SOUTHERN TIER AND GENESEE VALLEY
WHERE DOWNSLOPE WINDS COULD BRING MID TO UPPER 60S.

MONDAY NIGHT THIS HIGH PRESSURE WILL DRIFT EASTWARD AND ALLOW FOR A
SOUTHERLY FLOW TO DEVELOP. THIS FLOW WILL ALSO BRING ADDITIONAL
MOISTURE NORTHWARD WITH CHANCES FOR A FEW SHOWERS ACROSS WESTERN NEW
YORK BY DAYBREAK TUESDAY MORNING. COOLEST AREAS WILL BE TOWARDS THE
EAST WHERE THIS SOUTHERLY FLOW WILL DEVELOP LATER...AND HERE
OVERNIGHT LOWS MAY DROP DOWN TO AROUND 40.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
ON TUESDAY...MODEL CONSENSUS HAS A NARROW UPPER LEVEL RIDGE
ACROSS OUR REGION...WITH AND UPPER LEVEL LOW ACROSS THE CANADIAN
MARITIMES AND A TROUGH ACROSS THE UPPER PLAINS. THIS NARROW RIDGE
WILL EVENTUALLY BREAK DOWN...HOWEVER GUIDANCE DISAGREES EXACTLY
WHEN THIS WILL HAPPEN. 12Z GUIDANCE IS A BIT SLOWER THAN PREVIOUS
RUNS WITH SHOWERS LIKELY ACROSS THE SOUTHERN TIER BY TUESDAY
NIGHT...AND LOWER CHANCES TO THE NORTH WHICH WILL BE CLOSER TO THE
SURFACE HIGH. AFTER THIS...THE HIGH WILL TRY TO PUSH BACK
SOUTHWARD ACROSS OUR REGION LATE WEDNESDAY AND WEDNESDAY NIGHT
WITH MAINLY DRY CONDITIONS OUTSIDE OF A FEW LINGERING SHOWERS
ACROSS SOUTHERN AREAS. TEMPERATURES SHOULD BE NEAR TO A BIT ABOVE
NORMAL WITH DAYTIME HIGHS IN THE MID TO UPPER 60S. THESE COULD
TURN OUT A BIT WARMER IF DRIER/WARMER GUIDANCE TURNS OUT TO BE
CORRECT...BUT THE FORECAST WILL STAY NEAR MODEL CONSENSUS GIVEN
THE MODEL DISAGREEMENT.

THE 12Z GFS/ECMWF BOTH FINALLY PIVOT THE UPPER LEVEL TROUGH ACROSS
THE REGION THURSDAY NIGHT INTO FRIDAY WHICH WILL BRING A CHANCE OF
SHOWERS. THURSDAY SHOULD BE MOSTLY DRY AHEAD OF THIS...WITH
TEMPERATURES LIKELY TO CLIMB INTO THE 70S WITH A SOUTHERLY PRE-
FRONTAL FLOW AS LONG AS THE SHOWERS HOLD OFF LONG ENOUGH. FRIDAY
WILL BE COOLER...BUT HIGHS IN THE MID TO UPPER 60S ARE STILL NEAR
NORMAL FOR THIS TIME OF YEAR.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
REST OF THE AFTERNOON EVEN AS CLOUDS AND SOME SPRINKLES OR LIGHT
SHOWERS SPREAD FROM EAST TO WEST. AS AN UPPER LOW CONTINUES TO
BACK INTO THE REGION TONIGHT SHOWERS WILL SPREAD FURTHER WEST WITH
MVFR CLOUDS/VSBY POSSIBLE...MAINLY ACROSS THE HIGHER TERRAIN OF
THE SOUTHERN TIER. OTHER TAF ARE LIKELY TO REMAIN VFR WITH ONLY
LIGHT SHOWERS AND CLOUD DECKS ABOVE 3K FT.

SATURDAY...AS THE UPPER LOW MOVES AWAY AND A COLD FRONT BEGINS TO
APPROACH FROM THE NORTHWEST VFR WILL RETURN AT ALL LOCATIONS
THROUGH EARLY AFTERNOON. SOME SHOWERS AND POSSIBLY A TSTMS ARE
POSSIBLE FAR WEST (BUF/IAG) LATE SATURDAY AFTERNOON.

OUTLOOK...
SATURDAY NIGHT...MVFR WITH SHOWERS AND A CHANCE OF
THUNDERSTORMS.
SUNDAY...MAINLY VFR WITH A CHANCE OF MORNING SHOWERS EAST OF
KROC/KDSV.
MONDAY...VFR.
MONDAY NIGHT AND TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL PERSIST ACROSS THE LOWER
LAKES REGION THROUGH SATURDAY. THIS WILL RESULT IN LIGHT TO MODEST
WINDS PREDOMINATING...ALONG WITH CORRESPONDINGLY MINIMAL WAVES.

A COLD FRONT WILL THEN CROSS THE LOWER LAKES SATURDAY NIGHT...WITH
FRESHENING NORTHWESTERLIES IN ITS WAKE POTENTIALLY BRINGING A ROUND
OF ADVISORY-WORTHY CONDITIONS TO LAKE ONTARIO LATER SATURDAY NIGHT
AND SUNDAY. ON LAKE ERIE WINDS WILL BE A BIT WEAKER AND ALSO MORE
WESTERLY...LIKELY YIELDING CONDITIONS THAT WILL REMAIN BELOW ADVISORY
THRESHOLDS THROUGH THE WEEKEND.

&&

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

&&

$$

SYNOPSIS...AR/APFFEL
NEAR TERM...AR/APFFEL/JJR
SHORT TERM...THOMAS
LONG TERM...APFFEL
AVIATION...AR/JJR
MARINE...AR/JJR



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