Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221728 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 128 PM EDT FRI AUG 22 2014 .SYNOPSIS... A WEAK UPPER LOW OVER THE CATSKILL REGION OF NEW YORK WILL DRIFT TO THE SOUTHEAST AS AN EXTENSIVE UPPER RIDGE BUILDS FROM THE MISSISSIPPI VALLEY INTO EASTERN CANADA. THE EFFECT OF THESE WEATHER FEATURES WILL BE TO CREATE ENOUGH RIDGING AT THE SURFACE TO PUSH A BACKDOOR FRONT GRADUALLY WESTWARD TO THE ALLEGHENY FRONT BY SATURDAY MORNING. SCATTERED SHOWERS AND THUNDERSTORMS WILL OVER THE REGION TODAY INTO TONIGHT. AFTER A CLOUDY AND COOL START TO THE WEEKEND WITH AREAS OF DRIZZLE AND FOG...CONDITIONS WILL DRY OUT SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWERS AND ISOLATED THUNDERSTORMS FOCUSED OVER CENTRAL...WEST CENTRAL AND SOUTH CENTRAL MOUNTAINS EARLY THIS AFTERNOON IN VICINITY OF QUASI STATIONARY FRONT. POPS INCREASED ACCORDINGLY. BEST MOISTURE REMAINS WEST AND SOUTH OF AREA...BUT WITH 1.5" PW AVAILABLE...ANY SHOWERS AND THUNDERSTORMS WILL BE CAPABLE OF SOME HEAVY DOWNPOURS (AGAIN). GOOD NEWS IS THAT CELLS ARE MOVING AND NOT SHOWING SIGNS OF TRAINING...BUT SIMILAR TO YDY...NW TO SE STORM MOTION IN VICINITY OF QUASISTATIONARY BOUNDARY CAN PRODUCE IDEAL DIRECTIONAL SHEAR FOR LOCALIZED LLVL ROTATION. EARLIER FORECAST CONTINUES TO PLAY OUT WELL WITH BEST JET DYNAMICS AND LLVL THETA-E CONVERGENCE SHIFTING TO THE SCENT MOUNTAINS AND THE SUSQ VALLEY LATER THIS AFTERNOON AND EARLY EVENING. MAX TEMPS TODAY WILL VARY FROM THE MID 70S ACROSS THE NW...TO THE LOWER 80S THROUGHOUT THE LOWER SUSQ VALLEY. THESE READINGS WILL BE CLOSE TO NORMAL FOR LATE AUGUST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... SCTD TO NUMEROUS SHOWERS WILL BE FOUND MAINLY ACROSS OUR CENTRAL AND SWRN ZONES EARLY TONIGHT. AS THE AFOREMENTIONED BACKDOOR PUSHES WWD TO THE ALLEGHENY FRONT...CONVECTIVE PRECIP WILL WANE WITH STRATUS THICKENING UP/SPREADING WEST LATER TONIGHT. AREAS OF DRIZZLE AND RIDGE-SHROUDING FOG ARE LIKELY LATE TONIGHT THROUGH SATURDAY MORNING...WITH ANY LOW PROB FOR THUNDER LIMITED TO THE AREA WEST OF ROUTE 219. LOW TEMPS TONIGHT UNDER WIDESPREAD CLOUDS AND A LIGHT/MOIST EASTERLY LLVL FLOW WILL BE 60-65F. THE MOIST/ANOMALOUS EASTERLY SFC-850 MB FLOW ASCENDING THE APPALACHIANS SHOULD LEAD TO WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE/MTN TOP FOG PERSISTING THROUGH MOST OR ALL OF SATURDAY. THIS WILL HELP TO KEEP TEMPS WELL BELOW NORMAL /PERHAPS BY A SOLID 8-10F DURING THE DAY SATURDAY/. PORTIONS OF THE CENTRAL/NRN MTNS MAY STRUGGLE TO CLIMB OUT OF THE UPPER 60S...WITH LOCATIONS ACROSS THE SUSQ VALLEY...AND WEST OF RT 219 LIKELY REACHING THE LOWER TO MID 70S. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... A WEAK UPPER LOW MOVING UNDERNEATH THE RIDGE SHOULD ALLOW FOR A SLIGHT CHANCE FOR SHOWERS SATURDAY NIGHT. AFTERWARD...THE BUILDING RIDGE WILL BE THE PRIMARY DRIVER OF OUR WX THRU MOST OF THE EXTENDED FCST. MED RANGE GUIDANCE INDICATES HIGH PRES AND ASSOC DRY AIR MASS WILL DRIFT SOUTH LATE THIS WEEKEND...BRINGING FAIR AND BRIGHTER WX TO CENTRAL PA. PTSUNNY SKIES SHOULD HELP TEMPS REBOUND A BIT ON SUNDAY...BUT STILL REMAIN BLW NORMAL. LARGE SCALE SUBSIDENCE AND DRY AIR SHOULD PERSIST...AS THE MID RANGE MODELS ARE IN FAIR AGREEMENT OF A BUILDING RIDGE OVER THE REGION THROUGH EARLY NEXT WEEK. BY MID NEXT WEEK THE FCST CONFIDENCE BEGINS TO LOWER. BY THE MIDDLE OF NEXT WEEK...WHEN MED RANGE MODELS BEGIN TO DIVERGE. GEFS KEEPS RIDGE AND FAIR WX GOING THRU WED...WHILE ECMWF ENSEMBLE DATA INDICATES A WEAK COLD FRONT COULD PUSH SE INTO THE REGION...THE MODELS SEEM TO BE OFF WITH THEIR TIMING. HAVE KEPT A LOW CHC OF TSRA WED INTO THURSDAY. WHAT APPEARS CERTAIN IS THAT THE COOL TEMPS OF THIS WEEKEND WILL GIVE WAY TO A SLOW WARMING TREND THRU THE FIRST HALF OF NEXT WEEK...AS COOL AIR MASS MODIFIES UNDER STILL STRONG AUGUST SUN. GEFS AND EC ENS 850 TEMPS SUPPORT HIGH RETURNING TO ABV NORMAL BY WED. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... SHOWERS ARE MOST NUMEROUS ACROSS THE CENTRAL... WEST CENTRAL MOUNTAINS AND SOUTH CENTRAL MOUNTAINS AT MIDDAY AND EARLY THIS AFTERNOON...ALONG WITH ISOLATED EMBEDDED THUNDER. BRIEF TSTM VSBY AND CIG IMPACTS ARE POSSIBLE THROUGH LATE AFTERNOON...AND ANY LINGERING STORMS SHOULD DECREASE IN COVERAGE AND INTENSITY INTO TONIGHT. A LARGE AREA OF HIGH PRES WILL BUILD SWWD FROM ERN CANADA INTO THE NORTHEAST AND DOWN THE EAST SIDE OF THE APPLCHNS TNGT THRU THE WEEKEND. EASTERLY FLOW SHOULD BRING LOW CLOUDS/CIGS INTO THE FCST WITH SOME LIGHT RA/DZ EARLY SATURDAY WITH A FEW SHOWERS POSSIBLE LATER IN THE DAY. LOOK FOR IMPROVING CONDS SUN THRU TUE. OUTLOOK... SAT...MVFR/IFR IN THE MORNING WITH PATCHY FOG/BR/-DZ/-RA...BCMG VFR/MVFR IN THE AFTN WITH ISOLD-SCT SHRA. SUN...LOW CIGS PSBL EARLY THEN BCMG VFR. MON-TUE...VFR NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/CERU AVIATION...DEVOIR/STEINBUGL

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