000
FXUS61 KBUF 181134
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
734 AM 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 FORECAST AREA RAIN FREE. CONDITIONS WILL THEN BECOME MORE 
UNSETTLED AFTER THE WEEKEND WHEN A FRONTAL BOUNDARY WILL DRIFT SOUTH 
AND STALL OVER OUR REGION LATE MONDAY 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 DIMMED OUR 
SUNSHINE ON FRIDAY...AND WILL CONTINUE TO SHROUD THE SKIES WEST OF 
THE FINGER LAKES TODAY. 

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 LAKE ERIE DURING THE 
PAST 18 HOURS. A COUPLE OF THESE SHOWERS MAY CLIP PARTS OF THE 
WESTERN SOUTHERN TIER (MAINLY CHAUT CO) TODAY...BUT WITH 20 DEG F 
TEMP-DEW POINT SPREADS DURING MUCH OF THE DAY...THE BULK OF THE PCPN 
WILL DRY OUT OR FALL AS SPRINKLES.

THE SECOND FLY IN THE OINTMENT WILL BE THE INFLUX OF SOME ATLANTIC 
MOISTURE WITHIN THE RETURN AROUND THE AFOREMENTIONED SFC HIGH. THIS 
WILL MAINLY COME INTO PLAY ACROSS THE SRN TIER THIS AFTERNOON...
WHEN COUPLED WITH SOME WEAK DIURNAL INSTABILITY (MUCAPE 100-200 J/KG 
AND LI'S ARND ZERO)...THERE COULD BE SOME ISOLATED SHRA ACTIVITY. 
WILL CONTINUE TO COVER THIS WITH SLIGHT CHC POPS. 

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 SONDER 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).

BOILING ALL OF THIS DOWN...THE WRN COUNTIES CAN EXPECT ANOTHER DAY 
FILLED WITH MID AND HIGH LEVEL CLOUDS WITH PEAKS OF SUN WHILE 
PRTLY/MSTLY SUNNY SKIES WILL BE FOUND EAST OF LK ONTARIO. ANY 
ISOLATED SHOWERS TODAY WILL BE FOUND ACROSS THE WRN SOUTHERN TIER.
AS FAR AS TEMPS ARE CONCERNED...THE MERCURY THIS AFTERNOON SHOULD 
TOP OUT IN THE MID 70S AWAY FROM THE LAKES. 

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 /12Z SATURDAY THROUGH WEDNESDAY/...
WHILE THERE WILL BE PLENTY OF ALTO-CU AND CIRRUS STREAMING ACROSS 
THE WESTERN COUNTIES THROUGH THE FIRST HALF OF TONIGHT...VFR 
CONDITIONS WILL REMAIN IN PLACE.

OUTLOOK...  
SUNDAY THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...MOSTLY VFR WITH A CHANCE OF SHOWERS AND 
THUNDERSTORMS.

&&

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