Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 300946
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
546 AM EDT SUN AUG 30 2015

.SYNOPSIS...
INCREASING MOISTURE WILL BE CHANNELED NORTHEAST FROM THE OHIO
VALLEY TODAY...AND INTERACT WITH A STATIONARY FRONTAL BOUNDARY TO
PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS MAINLY
THE NORTHWESTERN HALF OF THE STATE. HIGH PRESSURE OFF THE MID
ATLANTIC COAST WILL BE MORE INFLUENTIAL ON KEEPING FAIR AND DRY
WEATHER INTACT ACROSS THE SOUTHEASTERN HALF OF PENNSYLVANIA.
VERY WARM AND INCREASINGLY HUMID WEATHER WILL CONTINUE INTO THE
MIDDLE OF THE UPCOMING WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RIGHT ENTRANCE REGION OF AN APPROX 60KT UPPER LEVEL WILL SLIDE
ACROSS SRN NEW YORK AND NRN PENN THIS MORNING AND EARLY AFTERNOON.
REGIONAL 88D MOSAIC LOOP SHOWS A COMPACT SHORT WAVE EMBEDDED
BENEATH THE TAIL END OF THIS JETLET /JUST NW OF KPIT AT 09Z/. THE
DISTINCT FEATURE AND ITS SPIN WILL CONTINUE TO TRACK TWD THE
NORTHEAST AND IMPACT PRIMARILY THE NW AND NORTH-CENTRAL MTNS OF
THE STATE WITH HUMEROUS SHOWERS. AREAL COVERAGE OF TSRA IS
STEADILY DECREASING /AS ONE WOULD EXPECT IN THE MORNING DURING THE
LATE SUMMER/.

SFC BASED CAPE WILL SLOWLY INCREASE TO BETWEEN 300-500 J/KG
ACROSS THE NW MTNS THIS MORNING WITH THE ADVECTION OF 1.5 INCH
PWAT AIR FROM THE OHIO VALLEY. THE PRESENCE OF A QUASI-STNRY
FRONTAL BOUNDARY AND THE INCREASING MOISTURE FROM THE OHIO
VALLEY...WILL LEAD TO NEWRD EXPANSION OF SHOWERS AND A FEW
ISOLATED TSRA EARLY TODAY.

TIMING OF THIS FEATURE PLACES IT ACROSS NCENT PENN DURING THE
CLIMATOLOGICALLY CONVECTIVE MIN PORTION OF THE DAY...SO EXPECT
VERY LITTLE IF ANY THUNDER THIS MORNING.

CLEAR TO PTLY CLOUDY SKIES WILL CONTINUE ACROSS MUCH OF CENTRAL
AND SOUTHERN PENN THROUGH THE LATE MORNING HOURS.

PATCHY LIGHT RIVER VALLEY FOG IS EXPECTED ACROSS SOUTH CENTRAL
AND SERN PENN THROUGH 13Z.

TEMPS AT SUNRISE SHOULD RANGE FROM THE UPPER 50S TO AROUND 60F
ACROSS MUCH OF THE CWA...WITH LOW-MID 60S FOUND ACROSS THE METRO
AREAS OF THE LOWER SUSQ VALLEY.

AFTER THE PASSAGE OF THE MESO-B SHORT WAVE LATE THIS
MORNING... DIFF NEG VORT ADVECTION WILL LEAD TO A MIN IN
CONVECTION BETWEEN 15-18Z. INDICATIONS /VIA A BLEND OF THE HRRR
AND WRF ARW/ ARE THAT CONVECTIVE...SHRA/ISOLATED TSRA WILL BE
CONFINED TO MAINLY THE NRN MTNS LAUREL HIGHLANDS DURING THE
AFTERNOON HOURS.

MUCH MORE ISOLATED SHRA/TSRA WILL BE FOUND NEAR...AND TO THE SE OF
A LINE FROM KFIG AND KIPT...TO KAVP.

THERE WILL BE A TRANSITION TO VIRTUALLY NO CHC OF RAIN OVER THE
SE COUNTIES OF OUR CWA.

BASIN AVG QPF WILL BE LESS THAN ONE TENTH OF AN INCH
TODAY. HOWEVER...A FEW COMMUNITIES UP NORTH COULD SEE 0.25-0.50
BY MIDNIGHT TONIGHT.

MAX TEMPS THIS AFTERNOON WILL VARY FROM THE U70S ACROSS THE NRN
AND WRN MTNS...TO THE UPPER 80S ACROSS THE LOWER SUSQ VALLEY AND
SURROUNDING AREAS WHERE MUCH MORE SUNSHINE WILL BE FOUND TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
RIDGE AT THE SFC AND ALOFT IS STARTING TO GET PRESSED A LITTLE TO
THE EAST BY AN ADVANCING UPPER TROUGH AND SLIGHT FEED OF GULF
MOISTURE. THUS...SUPPORT IN THE FORM OF INSTABILITY AND MOISTURE
WILL BE AVAILABLE TODAY.

AFTER THE INITIAL...RATHER COMPACT SHORTWAVE ALOFT LIFTS INTO
SOUTHCENTRAL NEW YORK LATER THIS MORNING...THE ATMOS WILL RECHARGE
TO OVER 1000 J/KG CAPE IN SOME AREAS...AND BE CAPABLE OF FIRING
OFF SCTD SHRA/TSRA ACROSS THE CENTRAL MTNS...AND ALLEGHENIES THIS
AFTERNOON.

HIGHS THIS AFTERNOON WILL VARY FROM THE U70S ACROSS THE NRN AND
WRN MTNS...TO THE UPPER 80S ACROSS THE LOWER SUSQ VALLEY AND
SURROUNDING AREAS.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ANOMALOUS UPPER LEVEL RIDGE WILL DOMINATE THE OHIO VALLEY AND
EASTERN UNITED STATES MUCH OF THE UPCOMING WEEK...WITH 850HPA
TEMPS RUNNING 16-18C WHICH WILL TRANSLATE TO WELL ABOVE-NORMAL
SFC TEMPS. THIS WARMTH AND INCREASING HUMIDITY SHOULD ALLOW FOR
AT LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY...BUT THE
PROBABILITY OF WIDESPREAD RAINFALL IS LOW.

THERE ARE A COUPLE OF INTERESTING FEATURES THAT BEAR WATCHING FOR
LATE IN THE LONG TERM PERIOD. THE FIRST IS THE REMNANTS OF
ERIKA...WHICH ARE FCST TO BE IN THE VICINITY OF THE FL/GA COAST BY
THE MIDDLE OF NEXT WEEK. AS THIS MOISTURE DIFFUSES OVER THE
SOUTHEAST U.S....SOME OF IT WILL GRADUALLY CRAWL INTO THE MID
ATLANTIC REGION. THE OTHER INTERESTING FEATURE IS A BACKDOOR COLD
FRONT THAT SOME MODELS BRING INTO THE MID-ATLANTIC STATES NEXT
THURS/FRI. THESE FEATURES COMBINED WITH THE WARM AND INCREASINGLY
HUMID AIR THAT WILL ALREADY BE IN PLACE WILL KEEP MENTION OF AT
LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY. THE LATTER
FEATURE COULD HAVE AN IMPACT ON TEMPS LATE NEXT WEEK...TAPERING
BACK TEMPS A BIT.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
CONVECTION OUT AHEAD OF AN APPROACHING TROUGH IS CURRENTLY
STREAMING THROUGH NORTHWEST PA...AND SHOULD ALLOW FOR SOME LIGHT
SHOWERS BRINGING POSSIBLE MVFR CIGS/VSBYS TO BFD. OTHERWISE PATCHY
AREAS OF FOG MAINLY MVFR WITH SOME ISOLATED AREAS OF IFR. THOUGH
GENERALLY LIGHT WINDS...ANY REGION THAT DECOUPLES SHOULD SEE
INCREASE FOG FORMATION. IFR CONDITIONS HAVE THE HIGHEST CHANCE AT
UNV...AOO AND BFD.

CONSIDERING THE SHORT RANGE MODELS...EXPECT A HIGH CHANCE FOR
SHOWERS ACROSS NORTHERN PENNSYLVANIA THIS MORNING. BY 16Z SHOWERS
MOVE INTO SOUTHWEST MOUNTAINS. USED MAINLY VCSH/VCTS TO HANDLE
SHOWERS AS THE PROBABILITIES ARE GENERALLY 20 TO 40 PERCENT.
HIGHEST PROBABILITIES OF SHOWERS/THUNDER IN NORTHWEST.

OUTLOOK...

MON...STILL SOME SHRA/TSRA POSS.
TUE-THU...NO SIG WX EXPECTED AREAS MVFR OVERNIGHT PATCHY FOG.

&&

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

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/RXR
AVIATION...GRUMM/CERU



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