741
FXUS61 KBUF 130754 CCA
AFDBUF
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE BUFFALO NY
352 AM EDT TUE AUG 13 2013
.SYNOPSIS...
SHOWERS AND SCATTERED THUNDERSTORMS ASSOCIATED WITH A PASSING COLD
FRONT WILL TAPER OFF TODAY. COLDER AIR ASSOCIATED WITH AN UPPER
LEVEL TROUGH WILL BRING A FEW MORE SHOWERS TONIGHT INTO WEDNESDAY
MORNING...ESPECIALLY FOR AREAS LOCATED EAST OF LAKE ONTARIO. HIGH
PRESSURE WILL THEN BRING DRY WEATHER AND SEASONABLY COOL
TEMPERATURES WEDNESDAY AND THURSDAY...BEFORE A WARMING TREND
BEGINS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWERS AND SCATTERED THUNDERSTORMS FORMING AHEAD OF THE APPROACHING
COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE AREA EARLY THIS
MORNING. EXPECT THE HEAVIEST RAIN TO IMPACT THE SOUTHERN TIER WHERE
THE LIFT IN THE VICINITY OF THE RIGHT FRONT QUADRANT OF A PASSING
UPPER LEVEL JET IS STRONGEST. ADDITIONAL HEAT AND MOISTURE FLUXES
FROM LAKE ERIE WILL ALSO COME INTO PLAY. PRECIPITABLE WATER VALUES
ARE AVERAGING BETWEEN 1.25 AND 1.5 INCHES. BASED ON THIS...A BRIEF
PERIOD OF MODERATE TO HEAVY RAIN IS POSSIBLE ANYWHERE AS THE FRONT
WORKS INTO WESTERN NEW YORK.
BY 12Z...THE COLD FRONT IS PROGGED TO BE OVER CENTRAL NEW
YORK...CLEARING THE EASTERN SECTION OF THE CWA DURING THE AFTERNOON.
SHOWERS WILL TAPER OFF FROM WEST TO EAST BEHIND THE FRONT...ALTHOUGH
LINGERING LOW LEVEL MOISTURE AND COLD AIR ADVECTION ALOFT WILL
LIKELY RESULT IN A FAIR AMOUNT OF AFTERNOON CU.
TONIGHT...THE SURFACE COLD FRONT WILL SLIDE OFF THE EAST
COAST...WHILE THE TRAILING UPPER LEVEL TROUGH PUSHES ACROSS NEW YORK
STATE. THE LIFT ASSOCIATED WITH THE PASSING TROUGH MAY GENERATE A
COUPLE OF SHOWERS DURING THE FIRST HALF OF THE NIGHT. AFTER
THAT...THE COMBINATION OF THE NORTHWEST UPSLOPE FLOW BEHIND THE COLD
FRONT AND INCREASINGLY UNSTABLE AIR OVER THE LAKES DUE TO ONGOING
COLD AIR ADVECTION WILL GENERATE SCATTERED SHOWERS SOUTHEAST OF THE
LAKES...ESPECIALLY LAKE ONTARIO WHERE SLIGHTLY DEEPER MOISTURE WILL
BE IN PLACE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY MORNING AN UPPER LEVEL LOW WILL BE OVER QUEBEC WITH
TEMPERATURES DOWN TO -20C AT 500MB NEAR KART. THIS WILL PROVIDE
ENOUGH INSTABILITY FOR THE POSSIBILITY OF ADDITIONAL SHOWERS OVER
THE EASTERN LAKE ONTARIO REGION AS A WEAK SECONDARY LOW LEVEL TROUGH
MOVES ACROSS THAT PORTION OF NY AS NOTED BY A WIND SHIFT AT 850MB.
IN THE SOUTHERN TIER...CLOUDS ARE EXPECTED INITIALLY FROM LAKE
EFFECT INFLUENCES IN THE MORNING AND THEN UPSLOPE NORTHWESTERLY FLOW
IN THE AFTERNOON. THERE MAY ALSO BE SOME MORNING VALLEY FOG
DEPENDING ON THE AMOUNT/LOCATION OF MORNING CLOUDS.
FOR THE REMAINDER OF WESTERN NY...EXPECT CLEAR OR MOSTLY CLEAR SKIES
AS A SURFACE RIDGE MOVES INTO THE OH VALLEY AND EXPANDS SLOWLY
TOWARD THE MID ATLANTIC COAST. LAKE SHADOWING WILL LIKELY KEEP
PLACES LIKE THE GENESEE VALLEY CLEAR FOR THE LATE MORNING AND
AFTERNOON.
THE MOST NOTABLE WEATHER HOWEVER WILL BE THE ANOMALOUSLY COOL FEEL
TO THE DAY WITH TEMPERATURES ABOUT 10F BELOW NORMAL...IN THE UPPER
60S OR NEAR 70 IN MOST LOCATIONS...ALONG WITH DEWPOINTS LOWERING TO
THE 40S INLAND FROM THE LAKES. THIS WILL GIVE THE REGION A EARLY
TASTE OF FALL.
WEDNESDAY NIGHT THE SURFACE RIDGE WILL CONTINUE BUILD...WITH LIGHT
WINDS AND CLEAR SKIES EXPECTED OVERHEAD. THUS EXPECT ANOTHER
RELATIVELY COOL NIGHT OVER THE REGION FOR AUGUST...WITH TEMPERATURES
IN THE 40S WELL INLAND. FOG IS EXPECTED IN THE INLAND VALLEYS
TOWARD THURSDAY MORNING.
THE SAME SURFACE HIGH PRESSURE WILL PROVIDE THE REGION WITH DRY
WEATHER ON THURSDAY WITH A CLASSIC LAKE SHADOWING DAY
EXPECTED...WITH INLAND CUMULUS AND CLEAR SKIES OVER THE LAKES AND
ADJACENT SHORELINES WEST AND SW OF LAKE ERIE AND ONTARIO.
ANOTHER NIGHT OF CLEAR SKIES IS EXPECTED FOR THURSDAY NIGHT WITH
HIGH PRESSURE STILL PROVIDING THE REGION WITH CONTINUED LIGHT
SUBSIDENCE OVERHEAD. THE OVERALL AIRMASS WILL BE A BIT WARMER WHEN
COMPARED TO WEDNESDAY NIGHT...BUT THERE WILL STILL BE ENOUGH
RADIATIONAL COOLING FOR ANOTHER LATE INLAND VALLEY FOG EVENT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE WILL REMAIN PARKED FROM THE GREAT LAKES INTO
NEW ENGLAND. MEANWHILE A LONGWAVE TROUGH ALOFT WILL REMAIN OVER THE
EASTERN U.S. THIS WILL BRING ANOTHER STRETCH OF DRY WEATHER TO THE
REGION...WHICH WILL LAST THROUGH THE WEEKEND. TEMPERATURES ON FRIDAY
WILL BE A BIT BELOW NORMAL...BUT HIGHS SHOULD WARM TO NORMAL FOR THE
UPCOMING WEEKEND.
12Z RUNS OF THE GFS/GGEM/ECMWF LIFT A SLUG OF MOISTURE WITH TROPICAL
ORIGINS INTO THE SOUTHEASTERN STATES THIS WEEKEND. A WEAK SOUTHERLY
FLOW ALOFT BETWEEN A TROF EXTENDING DOWN THE MISSISSIPPI AND HIGH
PRESSURE IN THE ATLANTIC WILL LIFT THIS MOISTURE INTO THE MID
ATLANTIC STATES BY MONDAY. THERE IS A CHANCE THIS MAY SNEAK INTO OUR
REGION ON MONDAY....HOWEVER A CONSENSUS OF GUIDANCE SUGGESTS THIS
WILL PROBABLY STAY TO OUR SOUTH.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SHOWERS AND SCATTERED THUNDERSTORMS AHEAD OF AN APPROACHING COLD
FRONT WILL SPREAD EAST ACROSS THE AREA EARLY THIS MORNING. MAINLY
VFR CONDITIONS WILL LOWER TO MVFR/IFR AT TIMES WITH ANY PASSING
THUNDERSTORM.
BEHIND THE COLD FRONT TUESDAY MORNING WINDS WILL INCREASE AND VEER
TO THE WEST NORTHWEST WITH GUSTS AVERAGING 15 TO 25 KNOTS...
ESPECIALLY SOUTH OF LAKE ONTARIO. SHOWERS WILL TAPER OFF FROM WEST
TO EAST...LINGERING LONGEST FROM THE GENESEE VALLEY EASTWARD WHERE
SOME DAY TIME INSTABILITY UNDER THE COOLER AIR ALOFT MAY BRING A
BRIEF SHOWER MIDDAY TUESDAY. CONDITIONS WILL SLOWLY IMPROVE BACK TO
MAINLY VFR AS CIGS RISE ABOVE 3K FEET FOR THE AFTERNOON HOURS ACROSS
THE REGION.
OUTLOOK...
TONIGHT...MVFR CIGS DEVELOPING SOUTH AND SOUTHEAST OF LAKE ONTARIO
WITH A CHANCE OF A SHOWER. ELSEWHERE MAINLY VFR. WEDNESDAY THROUGH
SATURDAY...VFR.
&&
.MARINE...
A COLD FRONT WILL PUSH ACROSS WESTERN NEW YORK EARLY THIS
MORNING...THEN SHIFT EAST OF LAKE ONTARIO BY EARLY AFTERNOON.
SOUTHWEST WINDS AHEAD OF THE FRONT WILL VEER TO THE WEST NORTHWEST.
THE COMBINATION OF MODERATE NORTHWEST WINDS AND COLD AIR ADVECTION
BEHIND THE FRONT WILL RESULT IN SMALL CRAFT ADVISORY CONDITIONS ON
LAKE ONTARIO LATER THIS AFTERNOON THROUGH WEDNESDAY MORNING.
EXPECT CONDITIONS TO REMAIN JUST BELOW SCA CRITERIA ON LAKE ERIE
DURING THIS PERIOD. WIND AND WAVES WILL THEN SUBSIDE A BIT ON
WEDNESDAY AS HIGH PRESSURE BUILDS EAST TOWARD THE LOWER LAKES.
THERE IS A CHANCE OF WATERSPOUTS TONIGHT ON LAKE ERIE AND LAKE
ONTARIO AS COLDER AIR DEEPENS OVER THE LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 AM EDT
WEDNESDAY FOR LOZ042>044.
&&
$$
SYNOPSIS...TJP
NEAR TERM...TJP
SHORT TERM...ZAFF
LONG TERM...ZAFF
AVIATION...TJP
MARINE...TJP