Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 312116 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 516 PM EDT FRI JUL 31 2015 .SYNOPSIS... HIGH PRESSURE OVER THE CENTRAL U.S. WILL NOSE INTO THE REGION THIS WEEKEND. A PERSISTENT UPPER LEVEL TROUGH WILL SIT OVER THE GREAT LAKES AND NORTHEAST STATES THIS WEEKEND...AND SEND A FEW WEAK FRONTS SOUTHEAST ACROSS PENNSYLVANIA. EACH OF THESE FRONTS WILL CONTAIN LIMITED MOISTURE...WITH THE ABILITY TO PRODUCE JUST SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... HIGH PRESSURE RIDGE EXTENDING NE INTO THE REGION FROM THE OHIO RIVER VALLEY WILL PROVIDE MOSTLY SUNNY SKIES ACROSS THE SOUTHEAST HALF OF PENN...WITH NEARLY ZERO CHC FOR SHOWERS. INCREASING MOISTURE...REFLECTED BY A FEW SW/NE ORIENTED RIBBONS OF HIGHER THETA-E AT 850 MB /AND 1.25-1.5 INCH PWATS/ WILL PUSH ACROSS NWRN PENN LATE THIS AFTERNOON INTO TONIGHT AHEAD OF AN UPPER TROUGH AND CFRONT DROPPING ESE FROM THE UPPER GLAKES. CU FIELD HAS EXPANDED AND GROWN ENOUGH VERTICALLY TO PRODUCE ISOLATED LIGHT SHOWERS ACRS THE NW MTNS INVOF KBFD...AND THIS COVERAGE IS EXPECTED TO GROW JUST SLIGHTLY THROUGH DUSK. SFC BASED CAPE /VIA THE MORE AGGRESSIVE NAM/ WILL REMAIN UNDER 500 J/KG ACROSS THE SE HALF OF THE STATE...WHILE RAMPING UP TO OVER 1000 J/KG ACRS FAR NWRN PENN BY 00Z SAT. 14Z RUN OF THE 13KM RAP...AND A SIMILAR SOLUTION GIVEN BY THE 09Z SREF INDICATE THAT ENOUGH INSTABILITY TO PRODUCE SCTD SHRA/TSRA WONT ARRIVE ACROSS OUR FAR NW ZONES UNTIL AT LEAST 02Z SAT /ENHANCED BY COOLING MID LEVELS AND INCREASING UPPER LVL DIFFLUENCE/. TEMPS ARE NEARING LATE AFTERNOON HIGHS THAT WILL BE SEVERAL DEG F ABOVE NORMAL. APPROACHING SFC TROUGH /CURRENTLY NEAR THE OHIO-PENN BORDER/ AND QUICKLY TRAILING CFRONT PUSHING THROUGH LOWER MICHIGAN ATTM....WILL BRING A FEW SHOWERS AND ISOLATED TSRA TO MAINLY THE NRN MTNS OF PENN LATE TODAY AND TONIGHT. CHC FOR ANY CONVECTION WILL QUICKLY DIMINISH TO THE SOUTH OF INTERSTATE 80. LOWS TONIGHT WILL VARY FROM THE MID 50S ACROSS THE NW MTNS...TO THE LOWER AND MID 60S THROUGHOUT THE SOUTHERN VALLEYS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... THE WEAK COLD FRONT WILL EXIT OUR EASTERN ZONES DURING THE MID TO LATE MORNING HOURS WITH ISOLATED-SCATTERED SHOWERS. AFTERWARD /AND VERY SIMILAR TO FRIDAY/...SFC HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE REGION FROM THE OHIO RIVER VALLEY. SFC DEWPOINTS SHOULD EDGE DOWN BY 3-5 DEG F COMPARED TO FRIDAY/S VALUES. THIS WILL LEAD TO MAINLY SCATTERED FAIR WEATHER CU...WITH LITTLE IF ANY CHC FOR AFTERNOON SHOWERS TO THE SOUTH OF I-80. SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /AROUND 6C PER KM/ ACROSS THE NRN MTNS WILL LEAD TO AREAS OF MDT TO TCU WITH A FEW SHOWERS DOTTING THE RADAR SCOPE AFTER 17Z. MAX TEMPS WILL BE NEAR NORMAL OVER THE CENTRAL AND SE VALLEYS...BUT A FEW DEG COOLER THAN NORMAL ACROSS THE NRN AND WRN MTNS. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... LITTLE CHANGE IS ANTICIPATED IN LARGE SCALE FLOW PATTERN ACROSS THE CONUS THROUGH THE EXTENDED PERIOD. A BROAD UPPER TROUGH EXTENDS SOUTHWARD FROM EASTERN CANADA ACROSS THE ERN U.S. TEMPERATURES SHOULD AVG NEAR NORMAL INTO EARLY NEXT WEEK BEFORE TRENDING COOLER LATER IN THE WEEK. SEVERAL SHORT WAVES WILL ROTATE AROUND THE UPPER LOW IN A FASHION REMINISCENT OF WINTER. AS IS THE CASE WITH MOST UPPER LOW VS. SHORT WAVE SPOKES...CONFIDENCE IS LOW ON TIMING OF PCPN CHANCES. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
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NICE MID SUMMER AFTERNOON OUTSIDE. VFR CONDITIONS PREVAIL ACROSS THE AREA. SOME SHOWERS AND STORMS NEAR THE LOWER LAKES...BUT THESE SHOULD STAY NORTH OF OUR AREA. ONLY MINOR CHANGES NEEDED FOR 21Z TAF PACKAGE. EARLIER DISCUSSION BELOW. SFC HIGH PRESSURE RIDGING NE INTO THE REGION FROM THE OHIO RIVER VALLEY...WILL SAG SE LATE TODAY AND TONIGHT...ALLOWING A WEAK SFC TROUGH...THEN MOISTURE CHALLENGED CFRONT TO SLIDE SE OVERNIGHT. ISOLATED TO SCTD SHOWERS AND TSRA ARE POSSIBLE LATE THIS AFTERNOON AND TONIGHT...MAINLY AT TAF SITES TO THE NORTH OF INTERSTATE 80. OTHERWISE...WIDESPREAD VFR WILL CONTINUE THROUGH THIS WEEKEND. OUTLOOK... SAT...MAINLY VFR...SCATTERED SHOWERS/THUNDERSTORMS. SUN...MAINLY VFR. MON-WED...VFR...EXCEPT FOR BRIEF MVFR IN ISOLATED-SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...MARTIN/TYBURSKI AVIATION...LAMBERT/MARTIN

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