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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBUF 190237
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1037 PM EDT SAT MAY 18 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF THE NEW ENGLAND COAST
THROUGH THE END OF THE WEEKEND AND WILL ALLOW WARMER AIR TO MOVE
INTO THE REGION FOR SUNDAY. MAINLY DRY WEATHER WILL CONTINUE THROUGH
MONDAY BEFORE A FRONTAL BOUNDARY STALLS OUT OVER THE REGION TUESDAY
THROUGH THE END OF NEXT WEEK WITH PERIODS OF SHOWERS AND
THUNDERSTORMS ALONG WITH WARM TEMPERATURES.

&&

.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
KBUF RADAR IS SHOWING MAINLY VIRGA STREAMING ACROSS THE WESTERN
END OF LAKE ONTARIO ASSOCIATED WITH SOME LIFT AND MOISTURE
EMBEDDED WITHIN THE JET STREAM ALOFT. DUE TO DRY LOWER LEVELS AS
OBSERVED BY 00Z KBUF RAOB....MOST OF THIS ACTIVITY IS EXPECTED TO
NOT MAKE IT TO THE GROUND. HOWEVER...A RECENT OBSERVATION OUT OF
TORONTO REPORTED VERY LIGHT RAIN. HAVE UPDATED THE FORECAST WITH
AN ISOLATED SPRINKLE ACROSS THE NIAGARA FRONTIER THROUGH MIDNIGHT.
OTHERWISE FORECAST REMAINS ON TRACK WITH SURFACE HIGH PRESSURE
CONTINUING TO DRIFT OFF THE NEW ENGLAND COAST OVERNIGHT. EXPECT
LOWS IN THE MID TO UPPER 50S ON THE LAKE PLAINS OF WESTERN
NY...WITH LOWER 50S ACROSS THE INTERIOR SOUTHERN TIER AND EAST OF
LAKE ONTARIO.

THE GFS REMAINS A WET OUTLIER WITH RESPECT TO SHOWER POTENTIAL
TONIGHT...AS IT LIFTS A BAND OF SHOWERS THROUGH THE FINGER LAKES AND
CENTRAL NY. IT APPEARS THE GFS IS MUCH TO AGGRESSIVE IN LOW LEVEL
MOISTURE RETURN AND CONVERGENCE. THE NAM IS ALSO LIKELY TOO
AGGRESSIVE IN POOLING MOISTURE ALONG LOW LEVEL BOUNDARIES AND
GENERATES SOME SPOTTY QPF TONIGHT. WITH NO APPARENT FORCING
MECHANISM AND RELATIVELY LIGHT LOW LEVEL FLOW...WILL OPT TO GO WITH
THE MUCH DRIER CANADIAN GEM SOLUTION AND KEEP A DRY FORECAST
OVERNIGHT. THERE WILL BE VARYING AMOUNTS OF CLOUD COVER WITH PERIODS
OF MID CLOUD ACROSS WESTERN NY. ACROSS THE NORTH COUNTRY MAINLY
CLEAR SKIES THIS EVENING WILL GIVE WAY TO INCREASING CLOUDS
OVERNIGHT AS THE RETURN FLOW PUSHES CLOUDS OVER PENNSYLVANIA
NORTHWARD.

ON SUNDAY THE SOUTHERLY RETURN FLOW WILL CONTINUE TO BOOST 850MB
TEMPS TO AROUND +12C. THIS SHOULD SUPPORT HIGHS IN THE UPPER 70S ON
THE LAKE PLAINS OF WESTERN NY WITH AN ADDED BOOST FROM DOWNSLOPE
FLOW. THE SOUTHERLY WINDS WILL BE STRONG ENOUGH TO PREVENT LAKE
BREEZES IN MOST LOCATIONS...WITH THE ONE EXCEPTION LIKELY BEING THE
LAKE ONTARIO SHORE FROM BRADDOCK BAY TO THE NIAGARA RIVER. HERE...
ENE FLOW WILL KEEP HIGHS IN THE LOWER 60S ALONG THE IMMEDIATE
LAKESHORE.

EXPECT ANOTHER DAY OF VARYING CLOUD COVER ACROSS THE REGION AS MID
LEVEL CLOUD AND INCREASING LOW LEVEL MOISTURE CROSS THE AREA. THE
GFS CONTINUES TO BE AGGRESSIVE IN DEVELOPING SHOWERS ACROSS MUCH OF
THE REGION...BUT AGAIN THIS LOOKS OVERDONE. THE LACK OF APPARENT
FORCING OR STRONGER LOW LEVEL FLOW WILL LIKELY PREVENT ENOUGH LOW
LEVEL CONVERGENCE OR MOISTURE POOLING TO SUPPORT ANY SHOWER CHANCES.
THE ONE EXCEPTION MAY BE ACROSS THE EASTERN LAKE ONTARIO REGION
WHERE LOW LEVEL WARM ADVECTION AND ISENTROPIC UPGLIDE IS MAXIMIZED.
HERE WE WILL CARRY A LOW CHANCE OF A SPOTTY SHOWER OR TWO...BUT
OTHERWISE WILL KEEP THE REST OF THE AREA DRY FOLLOWING THE DRIER NAM
AND CANADIAN GEM SOLUTIONS.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
SUNDAY NIGHT WILL BE RATHER QUIET...AND MILD WITH RIDGING ALOFT OVER
THE REGION. A LIGHT SOUTHERLY WIND WILL MAINTAIN LOWS IN THE LOWER
60S ACROSS LOWER ELEVATIONS AND UPPER 50S ACROSS THE INLAND
SOUTHWESTERN NYS AND THE NORTH COUNTRY.

ON MONDAY BENEATH THE UPPER LEVEL RIDGE AXIS THE LOW LEVEL MOISTURE
WILL INCREASE THROUGH THE DAY. THIS WILL INCREASE THE DEW POINTS AND
WITH A FAIR AMOUNT OF SUNSHINE THROUGH THE DAY A BIT OF A HUMID
AFTERNOON WILL BE IN STORE. HIGH TEMPERATURES ON MONDAY WILL CLIMB
INTO THE UPPER 70S AND LOWER 80S WHICH WILL PRODUCE A FAIR AMOUNT OF
INSTABILITY/CAPE. A WEAK COLD FRONT WILL CROSS THE REGION...HOWEVER
WITH THE UPPER LEVEL RIDGE AXIS REMAINING OVER THE AREA THERE WILL
JUST BE A LOW CHANCE POP FOR A FEW POP UP SHOWERS AND THUNDERSTORMS.

MONDAY NIGHT THE UPPER LEVEL RIDGE WILL BEGIN TO WEAKEN AS WEAK
IMPULSES OF ENERGY CREST THE RIDGE TOP. THE COLD FRONT BOUNDARY WILL
STALL JUST TO OUR SOUTH WITH A CONTINUE LOW CHANCE POP FOR A SHOWER
OR THUNDERSTORM OVERNIGHT. THE GREATEST CHANCE FOR A SHOWER OR
THUNDERSTORM WILL BE ACROSS SW NEW YORK IN PROXIMITY TO A
WARM FRONT THAT WILL BE FOUND ACROSS THE CENTRAL GREAT LAKE STATES.
ELEVATED INSTABILITY OF OVER 500 J/KG WILL BRING A THREAT OF SHOWERS
AND THUNDERSTORMS THROUGH THE NIGHT HERE. WITH LITTLE CHANGE TO THE
AIRMASS OVERNIGHT LOWS WILL BE SIMILAR TO SUNDAY NIGHT...WITH LOWS
IN THE LOWER 60S ACROSS WESTERN NEW YORK AND UPPER 50S ACROSS THE
NORTH COUNTRY.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
IN THIS TIME PERIOD SHOWERS AND THUNDERSTORMS WILL BE LIKELY
EARLY...WITH POSSIBLE COOLER AND DRIER AIR SETTLING OVER THE REGION
FOR THE START OF NEXT WEEKEND...THOUGH MODEL DIFFERENCES BRING A BIT
OF UNCERTAINTY FOR WHEN THIS WILL HAPPEN.

ON BOTH TUESDAY AND WEDNESDAY A CLOSED UPPER LEVEL LOW WILL BE
CENTERED OVER THE CENTRAL PLAINS WITH A ZONAL FLOW ALOFT OVER THE
EASTERN GREAT LAKES. DAYTIME INSTABILITY OF 1000+ J/KG ON TUESDAY
WILL LIKELY BRING SHOWERS AND THUNDERSTORMS. WEDNESDAY A SLIGHT
SOUTHWARD PUSH TO A WEAK FRONTAL BOUNDARY WILL LIKELY FOCUS THE
CONVECTION TOWARDS THE STATE LINE...WITH JUST A LOW CHANCE ACROSS
THE NORTH COUNTRY.

ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME THURSDAY AND
THURSDAY NIGHT WHEN THE SHORTWAVE FROM THE CENTRAL PLAINS PASSES
TOWARDS OUR REGION. UPPER LEVEL HEIGHT FALLS AND LOW LEVEL
CONVERGENCE AHEAD OF A COOL POOL OF AIR WILL BRING SHOWERS AND
PERHAPS SOME THUNDERSTORMS. INSTABILITY WILL NOT BE AS GREAT
THURSDAY...COMPARED TO TUESDAY AND WEDNESDAY.

THE ECMWF WILL PHASE THIS CENTRAL PLAINS LOW WITH A SHORTWAVE
DROPPING SOUTHWARD FROM EASTERN CANADA. THIS PHASING WILL DEVELOP A
TROUGH THAT WILL DRIVE A COLD FRONT ACROSS THE REGION THURSDAY
NIGHT. BEHIND THE COLD FRONT HIGH PRESSURE AND MUCH DRIER AND COOLER
AIR WILL FILTER ACROSS THE EASTERN GREAT LAKES. MEANWHILE THE GFS
DOES NOT PHASE THESE TWO TROUGHS OF LOW PRESSURE...AND CONTINUES A
CHANCE OF SHOWERS ON FRIDAY...KEEPING THE CORE OF THE COOLER AND
DRIER AIR ACROSS THE WESTERN GREAT LAKES. WILL CONTINUE WITH
CONTINUITY AND CONTINUE A LOW CHANCE POP FOR FRIDAY...WITH COOLER
AND DRIER AIR BUILDING ACROSS THE REGION FOR THE WEEKEND.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
VFR WILL PREVAIL TONIGHT AND SUNDAY. MID AND HIGH CLOUDS WILL
CONTINUE TO STREAM OVER WESTERN AND CENTRAL NY TONIGHT. KBUF RADAR
SHOWING SOME VIRGA/ISOLATED SPRINKLE STREAMING SOUTHEAST FROM THE
WESTERN END OF LAKE ONTARIO BUT THIS WILL NOT IMPACT TAFS.
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.
-- End Changed Discussion --

&&

.MARINE...
FINE RECREATIONAL BOATING CONDITIONS WILL REMAIN IN PLACE ON LAKES
ERIE AND ONTARIO THROUGH THE END OF THE WEEKEND. WINDS WILL
GENERALLY BE EAST AT 5 TO 15 KNOTS THROUGH SUNDAY WITH LIGHT WAVE
ACTION. TYPICAL OF SPRING...GENERALLY LIGHT WINDS WILL CONTINUE
THROUGH MUCH OF NEXT WEEK. THE CHANCES OF THUNDERSTORMS WILL
INCREASE TUESDAY THROUGH MUCH OF THE WEEK HOWEVER...WITH LOCALLY
STRONGER WINDS AND WAVES NEAR THUNDERSTORMS.

&&

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

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK/SMITH
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK/SMITH
MARINE...HITCHCOCK