000
FXUS61 KBUF 181738
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
138 PM EDT SAT MAY 18 2013

.SYNOPSIS...
HIGH PRESSURE OVER EASTERN QUEBEC WILL SETTLE SOUTH TO THE NEW
ENGLAND COAST LATER TONIGHT AND SUNDAY. THIS WILL KEEP THE MAJORITY
OF THE AREA RAIN FREE. CONDITIONS WILL THEN BECOME MORE UNSETTLED
NEXT WEEK WHEN A FRONTAL BOUNDARY WILL DRIFT SOUTH AND STALL OVER
OUR REGION MONDAY NIGHT AND TUESDAY. TEMPERATURES THROUGH THAT
PERIOD WILL AVERAGE ABOVE NORMAL.

&&

.NEAR TERM /THROUGH TONIGHT/...
WHILE GENERALLY FAIR WEATHER WILL BE FOUND ACROSS WESTERN AND
PARTICULARLY NORTH CENTRAL NEW YORK TODAY AND TONIGHT...THERE WILL
BE SOME FLIES IN THE OINTMENT. LETS START WITH THE BIG PICTURE AND
WORK DOWN FROM THERE.

BROAD RIDGING CENTERED OVER THE UPPER GREAT LAKES THIS MORNING WILL
AMPLIFY AND GRADUALLY BUILD EAST LATER TODAY AND TONIGHT...AND WHILE
THIS WILL PRODUCE WEAK SUBSIDENCE ACROSS OUR REGION...PLENTY OF MID
AND HIGH LEVEL MOISTURE WILL CONTINUE TO STREAM ACROSS OUR WESTERN
COUNTIES IN ADVANCE OF THE RIDGE AXIS. THIS MOISTURE WILL PROVIDE
PLENTY OF CLOUD COVER FROM THE FINGER LAKES WESTWARD ACROSS THE
GENESEE VALLEY AND WESTERN NY TODAY. THE NORTH COUNTRY WILL ESCAPE
MOST OF THIS WITH MOSTLY SUNNY SKIES THERE.

90-100KT H25 JETLETS FOUND WITHIN UPPER LEVEL MOISTURE HAS BEEN
LARGELY RESPONSIBLE FOR PRODUCING A SWATH OF SCATTERED SHOWERS FROM
LOWER MICHIGAN ACROSS SOUTHERNMOST ONTARIO TO CENTRAL LAKE ERIE
EARLIER THIS MORNING. LATEST RADAR IMAGERY SHOWS THIS HAS ALL BUT
DRIED UP...WITH JUST A FEW WEAK RETURNS LEFT. 12Z KBUF SOUNDING
SHOWED AN EXTENSIVE LOW LEVEL DRY LAYER...SO IT IS DOUBTFUL ANY OF
THIS WILL REACH THE GROUND. HAVE THUS REMOVED THE CHANCE OF
SPRINKLES FOR THIS AFTERNOON ACROSS THE WESTERN SOUTHERN TIER.

THE SECOND FLY IN THE OINTMENT WILL BE THE INFLUX OF SOME ATLANTIC
MOISTURE INTO THE SOUTHERN TIER WITHIN THE RETURN AROUND THE
AFOREMENTIONED SFC HIGH. MODEL GUIDANCE SEEMS TOO AGGRESSIVE IN
MOVING THIS MOISTURE INTO THE SOUTHERN TIER THIS AFTERNOON GIVEN
LATEST SATELLITE AND SURFACE OBSERVATION TRENDS...AND IS THUS LIKELY
OVERDONE IN THE DEVELOPMENT OF WEAK INSTABILITY. GIVEN THE LATEST
TRENDS...EXPECT THE SOUTHERN TIER TO REMAIN DRY THIS AFTERNOON.

THE REAL MOISTURE THOUGH WILL REMAIN WELL TO OUR SOUTH IN THE VCNTY
OF A STALLED FRONTAL BOUNDARY. FOR WHAT ITS WORTH...BLENDED AMSU AND
SSM SOUNDER IMAGERY DEPICTS PWAT VALUES OF ROUGHLY A HALF INCH
ACROSS OUR FORECAST AREA WHILE VALUES SOUTH OF THE FRONT APPROACH AN
INCH AND HALF (150% OF NORMAL).

AS FAR AS TEMPS ARE CONCERNED...THE MERCURY THIS AFTERNOON SHOULD
TOP OUT IN THE LOWER 70S AWAY FROM THE LAKES. AN ONSHORE EAST TO
NORTHEAST WIND WILL KEEP THE LAKE ONTARIO SHORE MUCH COOLER...ONLY
NEAR 60 WITH A FLOW OFF THE STILL CHILLY WATERS.

TONIGHT WILL FEATURE A LITTLE MORE CLOUD COVER FOR ALL OF THE
FORECAST AREA AS A SOUTHERLY LOW LEVEL FLOW WILL LIFT LOW AND MID
LEVEL MOISTURE NORTHWARDS FROM PENNSYLVANIA. WITH THE REMOVAL OF
DIURNALLY BASED INSTABILITY THOUGH...WILL NOT CARRY ANYTHING MORE
THAN SLGT CHC POPS FOR THE SRN TIER AND EVENTUALLY...THE EASTERN LK
ONTARIO REGION. GIVEN THE CLOUD COVER AND WEAK WARM ADVECTION
PATTERN...IT WILL BE MILDER THAN RECENT NIGHTS WITH LOWS GENERALLY
RANGING FROM THE MID 50S IN THE WEST TO THE UPPER 40S ACROSS THE
NORTH COUNTRY.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
ON SUNDAY...SURFACE-BASED RIDGING CENTERED OVER THE CANADIAN
MARITIMES WILL CONTINUE TO DRIFT EASTWARD...WHILE BROAD UPPER-LEVEL
RIDGING BUILDS EAST ACROSS NEW YORK STATE. THE RESULTANT WARM AIR
ADVECTION PATTERN WILL CONTINUE A SLOW INCREASE IN HUMIDITY AND
TEMPERATURE LEVELS...WITH SFC DEWPOINTS RISING INTO THE MID AND
UPPER 50S...AND TEMPS CLIMBING TO THE LOWER-MID 70S ACROSS THE
HIGHER TERRAIN AND MID-UPPER 70S ACROSS THE LOWER ELEVATIONS. WITH
850 MB TEMPS CLIMBING TO BETWEEN +12C/+13C ACROSS FAR WESTERN NEW
YORK...A FEW OF THE TYPICALLY FAVORED DOWNSLOPE FLOW AREAS WITHIN
THIS REGION COULD EVEN REACH THE 80 DEGREE MARK.

IN TERMS OF PRECIPITATION CHANCES...UNDER THE BUILDING UPPER RIDGE
THE BULK OF THE AREA SHOULD REMAIN LARGELY DRY WITH JUST SOME PARTLY
TO MOSTLY CLOUDY SKIES SUNDAY...THOUGH AN ISOLATED SHOWER OR TWO
STILL CANNOT BE TOTALLY RULED OUT GIVEN THE OVERALL WEAK/MODEST WARM
AIR ADVECTION PATTERN AND INCREASED OVERALL MOISTURE. THE ONE
POSSIBLE EXCEPTION TO THIS WILL BE ACROSS OUR FAR EASTERN ZONES...
WHERE THE BULK OF THE SHORT TERM GUIDANCE REMAINS RATHER CONSISTENT
IN DEPICTING A DEEPER PLUME OF ATLANTIC MOISTURE ALONG WITH SLIGHTLY
GREATER AMOUNTS OF WARM AIR ADVECTION...WHICH IS ENOUGH FOR A NUMBER
OF THE MODELS TO GENERATE SOME SPOTTY LIGHT SHOWERS. FOR THIS
REASON...HAVE BUMPED UP POPS FOR THIS REGION TO THE VERY LOW END OF
THE CHANCE RANGE ON SUNDAY...THOUGH EVEN HERE THE BULK OF THE DAY IS
LIKELY TO REMAIN DRY.

DURING SUNDAY NIGHT...THE AFOREMENTIONED RIBBON OF MOISTURE AND WEAK
ISENTROPIC LIFT WILL SLIDE EAST INTO NEW ENGLAND...LEAVING OUR AREA
DIRECTLY UNDER THE INFLUENCE OF THE UPPER RIDGE. THIS SHOULD RESULT
IN A DRY NIGHT...ALONG WITH RATHER MILD TEMPERATURES GIVEN THE
PREVAILING SOUTHERLY LOW LEVEL FLOW. EXPECT LOWS TO RANGE FROM THE
MID 50S ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND NORTH
COUNTRY TO THE LOWER 60S ACROSS THE THE LAKE PLAINS...WITH THE
CHAUTAUQUA COUNTY SHORELINE LIKELY SEEING THE WARMEST TEMPS OF ALL.

ON MONDAY...NEW YORK STATE WILL CONTINUE TO BE SITUATED FIRMLY
UNDERNEATH THE UPPER RIDGE...WITH THE FRONTAL ZONE ITS NORTHERN
PERIPHERY REMAINING DISPLACED TO OUR NORTH. THIS SHOULD RESULT IN
ANOTHER MAINLY DRY DAY...THOUGH WITH TEMPS/HUMIDITY LEVELS
CONTINUING TO SLOWLY RISE SOME ISOLATED DIURNALLY-DRIVEN CONVECTION
CANNOT BE TOTALLY RULED OUT. GIVEN WHAT SHOULD BE AT LEAST SOME
PARTIAL SUNSHINE...SOMEWHAT WARMER 850 MB TEMPS OF +13C TO +15C
SHOULD TRANSLATE INTO WIDESPREAD HIGHS IN THE UPPER 70S TO LOWER
80S...WITH A FEW SPOTS IN THE GENESEE VALLEY/FINGER LAKES EVEN
MAKING A RUN AT THE MID 80S. WITH SURFACE DEWPOINTS RISING INTO THE
60S...THIS SHOULD RESULT IN A WARM AND MODERATELY HUMID DAY...ONE
MORE TYPICAL OF SUMMER THAN MID SPRING.

MONDAY NIGHT...THE UPPER RIDGE WILL FINALLY GET KNOCKED BACK SOME BY
SHORTWAVE ENERGY DROPPING SOUTHEAST ACROSS ONTARIO AND QUEBEC. AT
THE LOWER LEVELS...THIS WILL ALLOW THE FRONTAL BOUNDARY TO OUR NORTH
TO SAG SOUTHWARD INTO OUR REGION...WHILE AT THE SAME TIME A WEAK
WAVE OF LOW PRESSURE RIDES EAST ALONG THIS BOUNDARY FROM THE WESTERN
GREAT LAKES. THE RESULTANT INCREASE IN LIFT AND MOISTURE ACROSS OUR
REGION WILL ALLOW FOR A SLOW INCREASE IN SHOWER AND THUNDERSTORM
CHANCES THROUGH THE NIGHT...FOR WHICH SOME LOWER-END CHANCE POPS
REMAIN IN THE FORECAST. OTHERWISE ANOTHER RATHER MILD AND MODERATELY
HUMID NIGHT CAN BE EXPECTED...WITH LOWS RANGING FROM THE UPPER 50S
TO MID 60S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
IN THE LONG TERM...EXPECT UNSETTLED CONDITIONS TO BE THE GENERAL
RULE TUESDAY THROUGH THURSDAY AS A WAVY FRONTAL BOUNDARY REMAINS IN
PLACE ACROSS THE GREAT LAKES REGION...AND MULTIPLE WAVES OF LOW
PRESSURE TRACK EAST ALONG THIS FEATURE. WITH THE EXACT TRACK/TIMING
OF THE SURFACE WAVES AND THEIR RESULTANT IMPACT ON THE POSITION OF
THE AFOREMENTIONED FRONTAL BOUNDARY REMAINING IN QUESTION THIS FAR
OUT...FOR NOW WILL JUST CONTINUE WITH BROADBRUSH SHOWER/THUNDERSTORM
CHANCES FOR TUESDAY THROUGH THURSDAY. AFTER THAT...PRECIPITATION
CHANCES SHOULD DIMINISH FOR FRIDAY AS THE PASSAGE OF ONE LAST
SURFACE WAVE FINALLY DISPLACES THE FRONT TO OUR SOUTH AND EAST.

WITH RESPECT TO TEMPS...THESE SHOULD CONTINUE TO AVERAGE ABOVE
NORMAL RIGHT THROUGH THURSDAY...BEFORE TRENDING COOLER FOR FRIDAY AS
COOLER/DRIER AIR RETURNS IN THE WAKE OF THE DEPARTING FRONTAL ZONE.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR WILL PREVAIL FOR THE 18Z TAF CYCLE. A WEALTH OF MID/HIGH CLOUDS
WILL CONTINUE TO STREAM OVER WESTERN AND CENTRAL NY THIS AFTERNOON
AND TONIGHT. EVENTUALLY SOME DEEPER LOW LEVEL MOISTURE WILL PUSH
NORTH THROUGH CENTRAL NY LATE TONIGHT AND THEN REACH THE EASTERN
LAKE ONTARIO REGION ON SUNDAY. STILL EXPECT CIGS TO BE VFR WITHIN
THIS AREA AS WELL. THE COMBINATION OF INCREASING MOISTURE AND WARM
ADVECTION MAY TOUCH OFF A FEW SCATTERED SHOWERS EAST OF LAKE ONTARIO
ON SUNDAY...BUT THESE SHOULD REMAIN LIGHT ENOUGH TO KEEP CIGS/VSBY
MAINLY VFR. FARTHER WEST EXPECT A CONTINUATION OF DRY WEATHER ON
SUNDAY WITH PERIODS OF MID/HIGH CLOUDS.

OUTLOOK...
MONDAY...VFR.
TUESDAY AND THURSDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS AND ASSOCIATED BRIEF MVFR/IFR.

&&

.MARINE...
FINE RECREATIONAL BOATING CONDITIONS WILL REMAIN IN PLACE ON LAKES
ERIE AND ONTARIO THIS WEEKEND. LIGHT EASTERLY WINDS CAN BE EXPECTED
TODAY WITH WINDS BACKING TO SOUTHEAST LATER TONIGHT AND SUNDAY. THE
WEAK SFC PRESSURE GRADIENT WILL LEND ITSELF TO LOCALIZED ONSHORE
FLOW EACH AFTERNOON. WAVES WILL BE NEGLIGIBLE.

LIGHT WINDS AND MINIMAL WAVES ARE EXPECTED FOR MONDAY AND TUESDAY AS
WELL...ALTHOUGH THERE WILL BE AN INCREASING CHANCE FOR SOME SHOWERS
AND THUNDERSTORMS.

&&

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

&&

$$

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