Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 300906 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 506 AM EDT THU JUL 30 2015 .SYNOPSIS... SHOWERS AND A FEW EMBEDDED THUNDERSTORMS WILL ACCOMPANY A COLD FRONT FROM THE WESTERN ALLEGHENIES INTO THE CENTRAL RIDGE AND VALLEY REGION EARLY TODAY...WITH ISOLATED STRONG TO SEVERE STORMS POSSIBLE THIS AFTERNOON IN SOUTHEASTERN PENNSYLVANIA. A NOTICEABLY DRIER AND LESS HUMID AIRMASS WILL OVERSPREAD THE AREA BEHIND THE FRONT ON FRIDAY...WITH SEASONAL TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS TO CLOSE OUT THE MONTH. && .NEAR TERM /THROUGH TONIGHT/... RADAR LOOP SHOWS A FRACTURED LINE/AXIS OF SHOWERS AND A FEW EMBEDDED TSTMS MOVING INTO THE ALLEGHENIES EARLY THIS MORNING IN ADVANCE OF SFC COLD FRONT. THE LATEST HRRR SHOWS THE FRONTAL PCPN BAND REACHING A LINE FROM WELLSBORO TO STATE COLLEGE TO BEDFORD BY 13Z. A VERY MOIST AIRMASS WILL RESIDE AHEAD OF THE FRONT WITH 70+F DEWPOINTS AND NARROW CORRIDOR OF PW VALUES AROUND 2.00 INCHES OR +2SD ABOVE THE MEAN. THIS WILL HELP SUPPORT THE POTENTIAL FOR SOME LOCALLY HEAVY DOWNPOURS...ESPECIALLY LATER THIS MORNING AND INTO THE EARLY-MID AFTERNOON HOURS ACROSS PARTS OF THE ERN CWA WHERE STRONGER INSTABILITY IS EXPECTED TO DEVELOP. THAT BEING SAID...SFC HEATING MAY BE LIMITED AHEAD OF THE FRONT DUE TO CLOUDS/PCPN. THIS WILL HAVE IMPLICATIONS FOR SEVERE WX POTENTIAL ACROSS ERN/SERN PA WITH A CONDITIONAL/MARGINAL RISK TIED TO DEGREE OF DESTABILIZATION. ALTHOUGH THE BEST LARGE-SCALE FORCING/HEIGHT FALLS AND BULK SHEAR WILL BE DISPLACED TO THE NORTH FROM NY INTO THE NEW ENGLAND...A FEW LOCALLY STRONG TO PERHAPS DAMAGING WIND GUSTS CANNOT BE RULED OUT OVER THE ERN 1/3 OF THE CWA WHERE SPC HAS MAINTAINED A MRGL RISK. SCT STORMS SHOULD PUSH EAST AND EXIT THE SE ZONES AROUND 5PM/21Z WITH A PLEASANT EVENING IN STORE FOR THE AREA. MAX TEMPS WILL TOP OUT AROUND 90F ACROSS THE MID TO LOWER SUSQ VALLEY...WITH HEAT INDEX VALUES APPROACHING 100F FOR A SHORT DURATION. RELIEF FROM THE HEAT/HUMIDITY WILL ARRIVE BY TONIGHT AS A NOTICEABLY DRIER LOW PW AIRMASS OVERSPREADS THE AREA FROM WEST TO EAST BEHIND THE COLD FRONTAL PASSAGE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... FAIR WEATHER WITH PLENTY OF SUNSHINE...SEASONAL TEMPERATURES AND COMFORTABLE HUMIDITY IS EXPECTED ON FRIDAY. STRONGER NW FLOW ALOFT WILL EXTEND FROM THE NORTHERN PLAINS THROUGH THE GREAT LAKES INTO THE WEEKEND...IN BETWEEN AN EXPANSIVE UPPER LEVEL RIDGE OVER THE SOUTHERN ROCKIES/PLAINS AND UPPER TROUGH/CLOSED LOW INVOF HUDSON BAY. THE FIRST...IN WHAT WILL BE A SERIES OF MOISTURE STARVED NRN STREAM COLD FRONTS...WILL MOVE INTO THE AREA ON SATURDAY AND BRING THE RISK OF SCT SHOWERS/ISOLATED TSTMS. MODEL CONSENSUS FAVORS NW AND N-CENTRAL PA WITH THE HIGHEST POPS /30-40 PCT/ FOR DAY 3/SAT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LITTLE CHANGE IS ANTICIPATED IN WHAT SHOULD BE A STABLE LARGE SCALE FLOW PATTERN ACROSS THE CONUS DURING THE FIRST WEEK OF AUGUST. UPPER RIDGE WILL CONTINUE TO DOMINATE OUT WEST WHILE A BROAD UPPER TROUGH EXTENDS SWD FROM EASTERN CANADA ACROSS THE ERN U.S. TEMPERATURES SHOULD AVG NEAR NORMAL INTO EARLY NEXT WEEK BEFORE TRENDING COOLER LATER IN THE WEEK. CONFIDENCE IS LOW ON TIMING OF PCPN CHANCES ASSOCD WITH NRN STREAM FRONTAL SYSTEMS. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... WIDESPREAD VFR WILL GIVE WAY TO INCREASING CLOUDS AND THE DEVELOPMENT OF SOME HAZE/THIN FOG. MOST TERMINALS WILL SEE VIZ SLIP TO 2-4 MILES IN THE HOURS AFTER MIDNIGHT WITH SOME LOW CLOUDS LIKELY ADVECTING NORTH INTO SOUTH-CENTRAL AREAS IN THE VERY HUMID TROPICAL AIRMASS. BY MORNING...SHOWERS AND SCATTERED THUNDERSTORMS WILL BEGIN MOVING INTO WESTERN AREAS AHEAD OF A COLD FRONT. THE FRONT WILL BE MOVING THROUGH EASTERN PA BY EARLY TO MID AFTERNOON SO SHOWERS/STORMS WILL NOT BE AN ALL DAY EVENT AT AREA AIRPORTS. DRIER CONDITIONS WILL DEVELOP WEST TO EAST IN THE WAKE OF THE FRONT. OUTLOOK... FRI...MAINLY VFR. SAT...MAINLY VFR...SCATTERED SHOWERS/THUNDERSTORMS. SUN...MAINLY VFR. MON...MAINLY VFR...SCATTERED SHOWERS/THUNDERSTORMS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...LA CORTE

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