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FXUS61 KCTP 031813
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
213 PM EDT FRI SEP 3 2010

.SYNOPSIS...

LAST DAY OF SUMMER LIKE WARMTH IS IN PROGRESS ACROSS CENTRAL
PENNSYLVANIA TODAY BEFORE A COLD FRONT BRINGS A TASTE OF FALL TO
THE COMMONWEALTH ON SATURDAY. AS A RESULT...THERE MAY BE A FEW
SHOWERS TONIGHT AND SATURDAY AS THE COOLER AIR OVERSPREADS THE
AREA. DRIER AND WARMER CONDITIONS WILL ARRIVE BY LATER SUNDAY AND
LABOR DAY.

&&

.NEAR TERM /THROUGH TONIGHT/...

CLOUDS CAN BE SEEN APPROACHING FROM THE WEST AS WELL AS THE
SOUTH...THE FIRST ASSOCIATED WITH A COLD FRONT AND THE SECOND
ASSOCIATED WITH HURRICANE EARL. RADAR SHOWS SCATTERED SHOWERS AND
SOME STORMS OFF TO THE WEST IN WHAT IS LEFT OF THE CONVERGENCE
ZONE WITH THE FRONT. SHORT RANGE MODELS ALL AGREE THAT THE
CONVERGENCE WEAKENS RAPIDLY AS THE FRONT PUSHES INTO WHAT IS
ESSENTIALLY THE WESTERN PERIPHERY OF THE LARGE HURRICANE
CIRCULATION.

THE RESULT WILL BE THAT ANY SHOWERS THAT FORM ALONG THE FRONT
AND MOVE INTO WESTERN SXNS WILL HAVE A TOUGH TIME ADVANCING
ACROSS PA LATER TODAY AND TONIGHT. HIGHEST CHANCES FOR RAIN WILL
BE OVER WESTERN AREAS WHERE SOME CONVECTION IS MOVING INTO WARREN
COUNTY AT THIS TIME. I USED A COMPROMISE BETWEEN THE GMOS AND
SREF POPS FOR THE REST OF THE AFTERNOON AND EVENING...BUT ACTUAL
QPF WILL BE RATHER MEAGER AS THE UPSTREAM MOISTURE IS RELATIVELY
SPARSE. SREF PROGS SHOW THE PWAT ANOMALY DISAPPEARING ALTOGETHER
AS THE FRONT FALLS APART OVER THE LOCAL AREA.

AFTER ANOTHER VERY WARM DAY...TONIGHT`S LOWS WILL STILL BE RELATIVELY
MILD...IN THE 50S AND 60S. THE REAL DROP OFF WILL BE SATURDAY AND
SAT NIGHT.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...

EARL WILL CONTINUE TO MOVE AWAY FROM THE REGION TONIGHT...SETTING
THE STAGE FOR A SHOT OF MUCH COOLER AIR TO MOVE INTO THE
REGION...A SIGN OF THINGS TO COME. SATURDAY LOOKS ALMOST FALL-LIKE
WITH PLENTY OF STRATO-CU AND EVEN SOME SCATTERED SHOWERS OVER THE
HIGH TERRAIN OF THE NORTH AND WEST. WITH A GUSTY WEST-NORTHWEST
WIND...IT WILL FEEL DOWNRIGHT CHILLY...ESPECIALLY WHERE THE
SHOWERS COINCIDE WITH HIGHS ONLY IN THE 50S AND 60S.

THE CHANCE OF SHOWERS WILL LINGER INTO SAT NIGHT IN THE CYCLONIC
FLOW OVER NORTHWESTERN PA...NEAREST LAKE ERIE. ELSEWHERE DRIER AIR
WILL GRADUALLY REESTABLISH ITSELF AS THE SURFACE HIGH REBOUNDS
RAPIDLY. SUNDAY LOOKS BRIGHT IN MOST AREAS...THOUGH STILL A
LITTLE ON THE UNSEASONABLY COOL SIDE.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HURRICANE EARL WILL UNDERGO EXTRATROPICAL TRANSITION AND MERGE
WITH ANOTHER DEEP CYCLONE OVER SOUTHEASTERN CANADA EARLY IN THE
PERIOD. THIS WILL AFFORD AN UNSEASONABLY STRONG/COLD WINTER-LIKE
CYCLONIC FLOW ALOFT WITH SEVERAL EMBEDDED H5 SHORTWAVE TROUGHS
MOVING THROUGH REGION ON SATURDAY. A VERY TIGHT SFC PRES GRADIENT
AND STEEP LOW LEVEL LAPSE RATES WILL PROMOTE FQNT 25-35MPH WLY WND
GUSTS...WHILE COLD AIR ALOFT COMBINES WITH WARM LAKE WATERS TO
SUPPORT SCATTERED TO NUMEROUS SHOWERS ACROSS THE NORTHWEST MTNS.
HIGH TEMPERATURES WILL EASILY BE 10-15 DEGREES COLDER THAN FRIDAY
AND AVERAGE 5-10 DEGREES BELOW EARLY SEPT CLIMATOLOGY.

THE DEEP VORTEX WILL LIFT NWD ACROSS QUEBEC SUN ALLOWING HIGH PRES
TO SLIDE ENEWD FROM THE LWR MS VLY INTO THE MID ATLC STATES. THE
HIGH PRES SYS IS EXPECTED REMAIN NEARLY STATIONARY THROUGH EARLY
NEXT WEEK BRINGING FAIR AND DRY WEATHER TO THE COMMONWEALTH. A RE-
LOADING WRN CONUS TROUGH WILL FAVOR RISING HTS DOWNSTREAM
ACCOMPANIED BY A RETURN TO ABOVE NORMAL TEMPS BY LATE IN THE
PERIOD. A PROGRESSIVE QUASI-ZONAL FRONTAL ZONE ON THE NRN
PERIPHERY OF THE SERN RIDGE WILL THREATEN THE NRN TIER WITH
SHOWERS BY MIDWEEK WITH A POSSIBLE FROPA WED-THUR.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...

THE REGION IS SANDWICHED BETWEEN TWO WEATHER SYSTEMS
TODAY...HURRICANE EARL OFF THE MID ATLANTIC COAST AND A COLD
FRONT ENTERING WESTERN PA.

THE APPROACHING COLD FRONT WILL BRING THE BULK OF THE WEATHER AS
EARL PULLS AWAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE TO MOVE INTO WESTERN SXNS...BEFORE DISSIPATING AS THEY
MOVE INTO CENTRAL AND EASTERN AREAS. SOME PATCHY MVFR CIG/VIZ
ISSUES COULD CROP UP OVER WESTERN AND NORTHERN HIGH
TERRAIN...ESPECIALLY WHERE IT RAINS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED TO DOMINATE.

CONSIDERABLE CLOUDINESS AND A FEW SHOWERS WILL LIKELY LINGER INTO
SATURDAY BEHIND THE FRONT ON SIGNIFICANTLY COOLER NW FLOW. CIGS
SHOULD STAY IN THE 3000-5000` RANGE FOR THE MOST PART.

OUTLOOK...

SUN-WED...MAINLY VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...STEINBUGL
AVIATION...LA CORTE

NWS CTP Office Area Forecast Discussion