Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 221144
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
744 AM EDT FRI MAY 22 2015

.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE WESTERN AND NORTH CENTRAL NEW YORK
WITH FAIR WEATHER AND COOLER THAN AVERAGE TEMPERATURES THROUGH
SATURDAY... BEFORE WARMER WEATHER RETURNS FOR THE REST OF THE
MEMORIAL DAY WEEKEND...ALONG WITH THE POTENTIAL FOR SOME SHOWERS
AND THUNDERSTORMS BY NEXT WEEK MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1145Z...A WEAK COLD FRONT IS IN THE PROCESS OF CROSSING
WESTERN AND NORTH CENTRAL NEW YORK...WITH REGIONAL SURFACE
OBSERVATIONS AND SATELLITE IMAGERY SUGGESTING THAT THE BOUNDARY
NOW LIES A LITTLE TO THE SOUTH OF A BUFFALO-ROCHESTER-WATERTOWN
AXIS. THE FRONT WILL CROSS THE REMAINDER OF THE REGION BETWEEN NOW
AND ABOUT 14Z/15Z...WITH THE LIMITED MOISTURE AND MODEST MID LEVEL
SUPPORT ALONG IT MERELY LEADING TO AN INCREASE IN CLOUD COVER AND
PERHAPS SOME SPOTTY LIGHT SPRINKLES...WITH DRY AND UNEVENTFUL
WEATHER OTHERWISE CONTINUING.

FOLLOWING THE FRONTAL PASSAGE...HIGH PRESSURE AND DRIER AIR
CENTERED OVER THE UPPER GREAT LAKES WILL BUILD SOUTHEASTWARD TO
PENNSYLVANIA THROUGH THE REMAINDER OF THE NEAR TERM PERIOD. THIS
SHOULD RESULT IN A GENERAL DECREASE IN CLOUD COVER...WITH SKIES
THEN CLEARING OUT ALTOGETHER TONIGHT. GIVEN THE DEVELOPMENT OF
SOME UPSLOPING...ANY LEFTOVER CLOUDS WILL PROBABLY LINGER THE
LONGEST ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER /FINGER
LAKES/NORTH COUNTRY. WHILE SOME OF THE SHORT TERM GUIDANCE /MOST
NOTABLY THE NAM12/ TRIES TO SPIT OUT SOME LIGHT QPF ACROSS THESE
LATTER AREAS THIS AFTERNOON...FEEL THAT THIS DEPICTION OF SUCH IS
LARGELY BOGUS GIVEN THE LIMITED AMOUNTS OF MOISTURE THAT SHOULD BE
IN PLACE.

WITH RESPECT TO TEMPERATURES...THE COLD AIR ADVECTION REGIME
DEVELOPING BEHIND THE FRONT WILL RESULT IN 850 MB TEMPS FALLING TO
WITHIN A COUPLE DEGREES EITHER SIDE OF ZERO CELSIUS BY THE EARLY
TO MID AFTERNOON HOURS. EVEN WHEN GIVEN GOOD MIXING...SUCH TEMPS
ALOFT WILL CONFINE AFTERNOON HIGHS TO THE MID TO UPPER 50S IN MOST
LOCATIONS...WITH THE EASTERN AND SOUTHEASTERN SHORES OF LAKES ERIE
AND ONTARIO KEPT SIGNIFICANTLY COOLER BY THE PREVAILING WESTERLY
/WEST-NORTHWESTERLY FLOW OFF THE MUCH COOLER LAKE WATERS. CLEARING
SKIES...PLENTY OF DRY AIR...AND LIGHTENING WINDS WILL THEN SET THE
STAGE FOR NEAR IDEAL RADIATIONAL COOLING TONIGHT... WHEN LOWS WILL
RANGE FROM THE MID AND UPPER 20S ACROSS INTERIOR SECTIONS OF THE
SOUTHERN TIER AND NORTH COUNTRY TO THE MID 30S ALONG THE IMMEDIATE
LAKESHORES. THIS WILL RESULT IN EITHER SOME FROST OR A FREEZE IN
MOST LOCATIONS AWAY FROM THE IMMEDIATE LAKESHORES TONIGHT...FOR
WHICH FROST ADVISORIES AND FREEZE WARNINGS ARE IN EFFECT AS
OUTLINED BELOW.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
THERE WILL BE A DISTINCT WARMING TREND DURING THIS PERIOD WITH A
NOTICEABLE DAY TO DAY INCREASE IN HUMIDITY. THIS WILL GRADUALLY
LEAD TO MORE UNSETTLED CONDITIONS WITH AN ESCALATING OPPORTUNITY
FOR SOME BADLY NEEDED RAINFALL. THE MAJORITY OF THIS PERIOD THOUGH
WILL BE PLEASANT WITH DRY WEATHER FEATURED FOR THE WEEKEND.

THIS PERIOD WILL BEGIN WITH UNSEASONABLY CHILLY AIR PARKED OVER
ALL OF NEW YORK STATE...AS MOST LOCATIONS WILL START THE DAY WITH
TEMPERATURES IN THE 30S. THE CHILLY AIR WILL BE TIED TO A CANADIAN
SFC HIGH...WHICH WILL DRIFT FROM THE UPPER OHIO VALLEY AT DAYBREAK
TO THE MID ATLANTIC COAST BY EVENING. THE RETURN FLOW AROUND THIS
EXITING FEATURE WILL ENCOURAGE WARM ADVECTION TO BECOME
ESTABLISHED OVER THE LOWER GREAT LAKES...WITH H85 TEMPS CLIMBING
FROM AROUND -2C IN THE MORNING TO 6C. THIS WARMING...COUPLED WITH
AN ABUNDANCE OF SUNSHINE WITHIN A VERY DRY AIRMASS...WILL SEND
AFTERNOON TEMPERATURES INTO THE 60S F ACROSS THE WESTERN COUNTIES
WHILE UPPER 50S WILL BE MORE COMMON EAST OF LK ONTARIO. A
SOUTHWEST FLOW MAY KEEP DOWNTOWN BUFFALO IN THE 50S AS WELL.

A FAIRLY PLEASANT...AND CERTAINLY LESS CHILLY NIGHT...WILL FOLLOW
SATURDAY NIGHT AS THE AFOREMENTIONED SFC HIGH WILL DROP ANCHOR OFF
THE MID ATLANTIC COAST. THERE SHOULD BE ENOUGH OF A SOUTHERLY FLOW
WITHIN A CONTINUED WARM ADVECTIVE PATTERN TO ONLY ALLOW THE
MERCURY TO FALL INTO THE 40S...SO ABSOLUTELY NO WORRY ABOUT A
SECOND NIGHT OF FROST.

ON SUNDAY...A BURGEONING RIDGE EXTENDING FROM THE OHIO VALLEY
BACK ACROSS THE UPPER GREAT LAKES WILL COMBINE WITH THE SFC HIGH
OFF THE MID ATLANTIC COAST TO PRODUCE A FINE DAY OVER OUR REGION.
WHILE CLOUDS WILL GRADUALLY INCREASE DURING THE COURSE OF THE
AFTERNOON...IT WILL FEEL MORE TYPICAL OF LATE MAY AS THE MERCURY
WILL CLIMB WELL INTO THE 70S FOR MOST AREAS.

CLOUDS WILL CONTINUE TO INCREASE AND THICKEN ACROSS WESTERN AND
NORTH CENTRAL NEW YORK SUNDAY NIGHT...AS A DEVELOPING WARM FRONT
OVER THE UPPER OHIO VALLEY WILL START TO PUSH NORTH. MOISTURE
MAKING ITS WAY ACROSS THIS BOUNDARY COULD PRODUCE SOME SHOWERS
LATER SUNDAY NIGHT...ESPECIALLY FOR SITES WEST OF THE FINGER
LAKES. THERE STILL DOES NOT SEEM ENOUGH INSTABILITY (SFC BASED OR
ELEVATED) TO SUPPORT THUNDERSTORMS...SO WILL CONTINUE TO LEAVE
THEM OUT OF THE OVERNIGHT PERIOD. JUST AS THE PRECEDING DAYS HAVE
BEEN PROGRESSIVELY WARMER...SUNDAY NIGHT WILL BE AT LEAST 5 DEG F
MILDER THAN THE PREVIOUS NIGHT AS LOWS ARE ONLY EXPECTED TO BE IN
THE LOW TO MID 50S. THESE READINGS WILL FINALLY MARK OUR RETURN TO
AN ABOVE NORMAL THERMAL REGIME.

IT WILL THEN BE RATHER UNSETTLED FOR MONDAY AND MONDAY NIGHT AS
THE AFOREMENTIONED WARM FRONT WILL SLOWLY ADVANCE TO THE NORTH
ACROSS OUR FORECAST AREA. THERE WILL CERTAINLY BE THE POTENTIAL
FOR SOME AREAS TO PICK UP MORE THAN A HALF INCH OF RAIN DURING
THIS UNSETTLED 24 HOUR PERIOD...BUT AVERAGE BASIN RAINFALL WILL
MORE LIKELY BE IN THE VCNTY OF A TENTH OR TWO. TEMPERATURES ON
MONDAY WILL REACH INTO THE MID AND UPPER 70S WHILE OVERNIGHT LOWS
MONDAY NIGHT WILL GENERALLY BE IN THE LOW TO MID 60S. THESE HIGHER
MERCURY READINGS WILL BE ACCOMPANIED BY DEW POINTS THAT WILL
EVENTUALLY REACH INTO THE 60S...MAKING IT FEEL INCREASINGLY HUMID.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
A BERMUDA HIGH PARKED OFF THE SOUTHEAST COAST WILL GUARANTEE THAT
THIS WILL BE A WARM AND HUMID PERIOD...AS A CONTINUAL FEED OF AIR
OUT OF THE DEEP SOUTH WILL MAKE ITS WAY OVER OUR REGION. THIS WILL
ALSO MEAN THAT OUR AIRMASS WILL INHERENTLY BE MORE UNSTABLE...
PARTICULARLY DURING THE HEAT OF THE DAY. GIVEN THE LACK OF ANY
SYNOPTIC BOUNDARIES THOUGH...CONVECTION WILL HAVE TO RELY LARGELY
ON LAKE BREEZE BOUNDARIES OR OROGRAPHICS TO INITIATE.

THAT BEING SAID...HAVE BACKED OFF ON POPS FOR MUCH OF THE LONG
TERM PERIOD. THE MAJORITY OF THE TIME PERIOD SHOULD BE RAINFREE...
SO WILL ONLY USE 30-40 CHC POPS.

TEMPERATURES WILL AVERAGE 10 TO 15 DEG F ABOVE NORMAL THROUGH THE
ENTIRE PERIOD...WITH DEW POINTS IN THE LOW TO MID 60S GIVING US A
TASTE OF STICKY SUMMER HUMIDITY.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A WEAK COLD FRONT WILL FINISH CROSSING THE REGION THIS MORNING...
WITH HIGH PRESSURE AND DRIER AIR THEN BUILDING INTO THE REGION
THROUGH THE REMAINDER OF THE TAF PERIOD. WITH ONLY LIMITED
MOISTURE AND MODEST MID LEVEL SUPPORT ACCOMPANYING THE FRONT...
THIS FEATURE IS NOT EXPECTED TO PRODUCE MUCH MORE THAN SOME
SPOTTY LIGHT SPRINKLES AS IT PASSES THROUGH. FLIGHT CONDITIONS
SHOULD REMAIN VFR THROUGH THE TAF PERIOD.

OUTLOOK...
SATURDAY AND SUNDAY...VFR.
MONDAY...VFR/MVFR WITH SHOWERS LIKELY AND A CHANCE OF THUNDERSTORMS.
TUESDAY...VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS/ATTENDANT MVFR.

&&

.MARINE...
FRESHENING WESTERLIES TO WEST-NORTHWESTERLIES DEVELOPING IN THE
WAKE OF A WEAK COLD FRONT WILL GENERALLY REMAIN BELOW ADVISORY
LEVELS TODAY. THE ONE EXCEPTION TO THIS WILL BE ALONG THE
SOUTHEASTERN SHORE OF LAKE ONTARIO... WHERE A BRIEF PERIOD OF
MARGINALLY ADVISORY-WORTHY WINDS AND WAVES IS EXPECTED LATE THIS
AFTERNOON AND THIS EVENING...BEFORE CONDITIONS IMPROVE AGAIN
OVERNIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION.

AFTER THAT...LIGHT TO MODEST WINDS AND RELATIVELY MINIMAL WAVES
ARE THEN EXPECTED SATURDAY AND SUNDAY AS SPRAWLING HIGH PRESSURE
SLOWLY DRIFTS FROM THE SPINE OF THE APPALACHIANS TO A POSITION
JUST OFFSHORE OF THE MID ATLANTIC COASTLINE.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR
     NYZ005>008-012-013-019>021-085.
     FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR
     NYZ001>004-010-011-014.
MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 11 PM EDT
         THIS EVENING FOR LOZ043-044.

&&

$$

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



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