Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 021633
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1233 PM EDT THU JUL 2 2015

.SYNOPSIS...
SHOWER AND THUNDERSTORM CHANCES WILL BE FOCUSED MAINLY TO THE
SOUTH OF PENNSYLVANIA THROUGH THE END OF THE WEEK...NEAR A
NEARLY STATIONARY FRONTAL BOUNDARY. AN UPPER LEVEL TROUGH WILL
MOVE ACROSS THE AREA ON SATURDAY ACCOMPANIED BY THE GREATER RISK
FOR MORE WIDESPREAD SHOWERS FOR INDEPENDENCE DAY. A DRIER WEATHER
PATTERN SHOULD BRIEFLY VISIT THE REGION EARLY NEXT WEEK BEFORE
UNSETTLED CONDITIONS RETURN BY NEXT WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
DEEP LAYER MOISTURE GRADIENT LIES ACROSS THE MASON DIXON LINE
EARLY THIS AFTERNOON...SEPARATING MORE SOUPY 1"+ PW FROM SUB
0.75" PW ACROSS NORTH CENTRAL PA. MEAN UPPER TROF WILL LIE ACROSS
THE REGION THIS AFTERNOON WITH WEAK SHEAR AXES TRACKING ALONG AND
SOUTH OF THE PA/MD BORDER. ONE AREA OF SHOWERS HAS MOVED EAST OF
MY SOUTHERN TIER BY MID MORNING. WITH DIURNAL HEATING...EXPECT
ISOLD TO SCT CONVECTIVE DEVELOPMENT LATER ON ALONG AND SOUTH OF
THIS THIS SAME AREA.

WITH LITTLE TO NO BOUNDARY LAYER FLOW OR SFC MOISTURE CONVERGENCE...
ISOLD CONVECTIVE INITIATION SHOULD OCCUR ON HIGHER TERRAIN TO THE
SOUTH OF MY AREA THIS AFTERNOON AND MEANDER ENE ALONG THE MOISTURE
GRADIENT... REMAINING MOSTLY ALONG AND SOUTH OF THE MASON DIXON
LINE. LATEST HRRR RUN CONTS TO GENERATE A CLUSTER OF SHOWERS WHICH
WOULD LIKELY PRODUCE ISOLATED THUNDER CLIPPING THE SOUTH CENTRAL
MOUNTAINS AND LOWER SUSQ RIVER VALLEY THIS AFTERNOON. CONVECTION
DIES DOWN BY 02Z WITH FAIR CONDITIONS OVERNIGHT AND SOME LATE
NIGHT VALLEY FOG...ESPECIALLY SOUTH.

MINS TONIGHT WILL BE CHILLY IN THE NORTH WITH READINGS IN THE
40S...AND RANGING FROM THE 50S TO THE LOWER 60S ACROSS CENTRAL AND
SOUTHEAST PA RESPECTIVELY.

&&

.SHORT TERM /FRIDAY/...
SHORTWAVE ROUNDING BASE OF UPPER TROF OVR THE MIDWEST WILL CAUSE
STATIONARY FRONT TO WAGGLE NORTHWARD DURING THE DAY FRIDAY AS
AS A WEAK AREA OF LOW PRESSURE RIPPLES ALONG IT FROM THE OHIO
VALELY. DEEP LAYER MOISTURE INCREASES SOUTH OF THE BOUNDARY ACROSS
THE SOUTHERN TIER...INCREASING CHC OF SHOWERS THERE DURING THE
AFTERNOON. ISOLD TSRA POSSIBLE ACROSS THE LAUREL HIGHLANDS AND
SOUTH CENTRAL MOUNTAINS. NORTH WILL STILL BE LARGELY PROTECTED
FROM CONVECTION THANKS TO MUCH LOWER DEEP LAYER MOISTURE AND STABLE
STRATIFICATION.

HIGHS ON FRIDAY WILL RANGE GENERALLY IN THE MID TO UPPER 70S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
DESPITE MINOR TIMING DIFFERENCES AMONG MED RANGE MDLS...THE
OVERALL PATTERN APPEARS FAIRLY CERTAIN. MEAN UPPER LVL TROF WILL
REMAIN CENTERED WEST OF PA...RESULTING IN REGULAR OPPORTUNITIES
FOR RAIN. ECENS/GEFS INDICATE THE BEST CHC FOR SHOWERS WILL
ACCOMPANY PASSAGE OF SHORTWAVES SAT AND WED. LATEST GUIDANCE
SUGGESTS SCT SHOWERS SAT WILL BE LIGHT AND CONCENTRATED VERY
EARLY IN THE DAY...AS DEEP MOISTURE REMAINS SOUTH OF THE BORDER AND
WAVE PASSES EAST OF THE STATE BY MIDDAY. WILL MAINTAIN A SLIGHT
CHC OF DIURNALLY-DRIVEN CONVECTION SUN-TUE...DUE TO MDLS
DEPICTION OF A WEAK CUT OFF UPPER LOW OVR THE CENTRAL
APPALACHIANS. HOWEVER...DEEP MOISTURE AND OPPORTUNITY FOR
MEANINGFUL RAINFALL SHOULD HOLD OFF UNTIL APPROACH OF COLD FRONT
AND POSITIVE PWAT ANOMALIES WED.

GEFS/ECENS OUTPUT IMPLY TEMPS FAIRLY CLOSE TO AVERAGE FOR EARLY
JULY. SAT IS LIKELY TO BE A BIT COOL DUE TO CLOUD COVER/SCT SHOWERS
AND LINGERING LL EASTERLY FLOW. HOWEVER...SW FLOW IN ADVANCE OF
AN APPROACHING COLD FRONT IS LIKELY TO PUSH TEMPS A BIT ABV
AVERAGE BY TUE/WED OF NEXT WEEK.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR WILL PREVAIL THIS AFTN WITH A LOW RISK FOR AN ISOLD
SHOWER/TSTM OVER THE EXTREME SRN AIRSPACE...NEAR FRONTAL ZONE
POSITIONED OVER NRN MD/VA. EXPECT PCPN TO BE CONFINED OVER THE FAR
SRN AIRSPACE LATER TONIGHT INTO EARLY FRIDAY AS LOW PRESSURE
TRACKS ENEWD FROM THE TN VLY INTO THE DELMARVA.

OUTLOOK...

FRI...VFR/MVFR WITH CHC OF SHOWERS OVER THE SRN 1/3 OF AIRSPACE.

SAT...VFR/MVFR WITH CHC OF SHOWERS.

SUN-MON-TUE...NO SIG WX.

&&

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

&&

$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/CERU
AVIATION...DEVOIR/STEINBUGL


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