Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 031139 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 739 AM EDT FRI JUL 3 2015 .SYNOPSIS... AN AREA OF HIGH PRESSURE WILL SLIDE ACROSS NORTHERN PENNSYLVANIA AND SOUTHERN NEW YORK STATE TODAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA ON SATURDAY...WITH SURFACE LOW PRESSURE DRIFTING FROM THE CENTRAL APPALACHIANS TO THE SOUTHER NEW JERSEY COAST TONIGHT THROUGH SATURDAY MORNING. THESE WEATHER FEATURES WILL COMBINE TO BRING PERIODS OF RAIN TO MUCH OF CENTRAL AND SOUTHERN PENNSYLVANIA TONIGHT THROUGH THE MORNING HOURS OF INDEPENDENCE DAY. WEAK HIGH PRESSURE BUILDING INTO THE REGION FOR SATURDAY AFTERNOON AND NIGHT SHOULD LEAD TO A DECREASING CHANCE FOR SHOWERS...UNDER MOSTLY CLOUDY SKIES WITH LIGHT WIND. A DRIER WEATHER PATTERN SHOULD BRIEFLY VISIT THE REGION EARLY NEXT WEEK BEFORE UNSETTLED CONDITIONS RETURN BY NEXT WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1016 MB SFC HIGH PRESSURE RIDGE EXTENDED FROM NEAR TORONTO... SOUTHEAST TO THE FINGER LAKES REGION OF NEW YORK. WEAK NORTHERLY FLOW AND LLVL NEG THETA-E ADVECTION WILL BE TOPPED BY INCREASING MID AND HIGH CLOUDS FROM THE SOUTHWEST...MAINLY DURING THE MIDDAY AND AFTERNOON HOURS ACROSS CENTRAL AND NRN PENN. A RELATIVELY COMFORTABLY COOL EARLY MORNING IS IN STORE FOR THIS TIME OF YEAR...WITH CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WIND. SFC DEWPOINTS IN THE U40S TO LOWER 50S ACROSS THE NORTH WILL ALLOW THE AIR TO COOL SUFFICIENTLY TO PRODUCE PATCHY DENSE RIVER VALLEY FOG. AN ALREADY TIGHT T/TD SPREAD WITH SFC DEWPOINTS IN THE U50S TO LOWER 60S ACROSS THE SOUTH WILL OCCUR BENEATH A SHIELD OF GENERALLY THIN HIGH CLOUDS. EXPECT AREAS OF FOG TO FORM IN THIS AREA TOO...ESPECIALLY ACROSS THE LOWER SUSQ VALLEY. MINS EARLY TODAY 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. SHORTWAVE ROUNDING BASE OF UPPER TROF OVR THE MIDWEST WILL CAUSE STATIONARY FRONT /EXTENDING FROM THE LOWER OHIO VALLEY TO THE VIRGINIA PIEDMONT/ TO DRIFT BACK TO THE NORTH DURING THE DAY TODAY AS AS A WEAK AREA OF LOW PRESSURE RIPPLES ALONG IT FROM THE OHIO VALLEY. DEEP LAYER MOISTURE INCREASES SOUTH OF THE BOUNDARY ACROSS THE SOUTHERN TIER...INCREASING CHC OF SHOWERS THERE DURING THE AFTERNOON HOURS. ISOLD TSRA ARE POSSIBLE ACROSS THE LAUREL HIGHLANDS..AND TO A LESSER EXTENT OVER SOUTH CENTRAL MOUNTAINS THIS AFTERNOON. SREF PROB OF CAPE EXCEEDING 1000 J/KG REACHES AROUND 50 PERCENT ACROSS WRN PENN...BUT A SHARP GRADIENT OF DECREASING VALUES OCCURS AS YOU HEAD EAST TOWARD ROUTE 219. THE NORTHERN ZONES WILL STILL BE LARGELY PROTECTED FROM CONVECTION THANKS TO MUCH LOWER DEEP LAYER MOISTURE AND STABLE STRATIFICATION. HIGHS THIS AFTERNOON WILL RANGE GENERALLY IN THE MID TO UPPER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... ANOMALOUS 925-850 MB SERLY FLOW DEVELOPS AND IMPINGES ON THE LAUREL HIGHLANDS LATE THIS AFTERNOON/EVENING...WITH THE AXIS OF THE LLVL WIND MAX SLIDING ACROSS THE SUSQ VALLEY TONIGHT...BEFORE AIMING INTO NORTHEAST PENN EARLY SATURDAY. THIS WEATHER FEATURE...AND A FEW AREAS OF NOTABLY STRONG 850-700 FGEN WILL COMBINE TO BRING PERIODS OF RAIN TO MUCH OF CENTRAL/SOUTHERN PENN AND THE SUSQ VALLEY/WRN POCONOS TONIGHT THROUGH 15Z SATURDAY. BASIN AVG QPF FOR THE UPCOMING 12-16 HOUR EVENT HAS BEEN INCREASED QUITE DRAMATICALLY TO 3 TO 4 TENTHS OF AN INCH WITH SOME LOCATIONS ACROSS THE LAURELS...AND COMMUNITIES EAST OF THE SUSQ MAINSTEM...SEEING UP TO 0.75 OF AN INCH BY NOON SATURDAY. MOST OF NORTHERN PENN WILL SEE LIGHTER RAIN AMOUNTING TO LESS THAT 0.25 OF AN INCH. RAIN SHOULD TAPER TO ISOLATED-SCTD SHOWERS SATURDAY AFTERNOON...WITH A POSSIBLE RELATIVE MIN EXTENDING FROM SCENT PENN TO THE WEST BRANCH VALLEY OF THE SUSQ RIVER. SKIES WILL REMAIN MOSTLY CLOUDY TO CLOUD THOUGH AS VERY LIGHT WINDS IN THE LOWEST 2 KM WILL DO LITTLE TO MIX OUT THE PRECEDING DEEP MOISTURE. WE SURELY AREN/T HAVING MUCH LUCK WITH TEMPERATURES ON SATURDAYS GETTING ANYWHERE THIS WEEK OR LAST. MUCH BELOW NORMAL MAX TEMPS ARE IN THE FORECAST FOR THE 4TH THANKS TO THICK CLOUD COVER...EASTERLY UPSLOPE FLOW IN MANY PLACES...AND SOME LIGHT RAIN -ESPECIALLY IN THE MORNING ACROSS THE EASTERN HALF OF THE STATE. HIGHS SATURDAY WILL STRUGGLE TO REACH THE UPPER 60S...TO LOWER 70S DURING THE MID TO LATE AFTERNOON HOURS...AFTER THE STEADIER RAIN ENDS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... 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 LIGHT RAIN WILL ACCOMPANY PASSAGE OF SHORTWAVES LATE TONIGHT/SAT MORNING...THEN AGAIN ON 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. CURRENT MODEL RUNS ARE SHOWING A MORE ORGANIZED BAND THAT WILL POSSIBLY MOVE THROUGH THE STATE LATE AFTERNOON INTO EARLY EVENING. HAVE SLIGHTLY INCREASED THE CHANCE OF PRECIPITATION ON SATURDAY. 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 /12Z FRIDAY THROUGH TUESDAY/...
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EXPECT LOCAL IFR/LIFR CONDS AT AOO/JST TO DISSIPATE BY 13Z. VFR WILL PREVAIL INTO THE AFTN WITH SCT-BKN 050 CIGS DEVELOPING FROM SOUTH TO NORTH. MID AND HIGH CLOUDS WILL ALSO STREAM IN FROM THE SW AHEAD OF SHORTWAVE APPROACHING FROM THE OHIO VALLEY. THE OH VLY SHORTWAVE AND ASSOCD SFC LOW WILL TRACK EWD ACRS THE APPALACHIANSAND THRU THE MID ATLC AND BRING RAIN AND REDUCED FLYING CONDS TO THE ENTIRE AIRSPACE TONIGHT INTO SATURDAY. OUTLOOK... SAT...MVFR IN RAIN/SHRA. SUN...BCMG VFR. NO SIG WX. MON-TUE...VFR WITH LOW CHC OF SHOWERS/TSTMS.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...FITZGERALD/LAMBERT AVIATION...STEINBUGL

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