Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 220734 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 334 AM EDT FRI AUG 22 2014 .SYNOPSIS... THE BUILDING RIDGE OVER EASTERN CANADA WILL SLOWLY CREATE ENOUGH RIDGING AT THE SURFACE TO PUSH A BACKDOOR FRONT INTO THE REGION. THIS WILL SLOWLY DRY THINGS OUT SATURDAY INTO SUNDAY AND EARLY NEXT WEEK. BUT UNTIL THEN THE MOISTURE BOUNDARY AND SLOW MOVING WEAK WAVES WILL CONTINUE TO PRODUCE SHOWERS AND THUNDERSTORMS OVER THE REGION INTO SATURDAY. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... MOSTLY CLOUDY SKIES WITH A FEW LONE SHOWERS AND PATCHY FOG WERE NOTED ACROSS THE REGION EARLY THIS MORNING. SHORT RANGE/HIGH RES MODELS INDICATE VERY LITTLE CHANGE THROUGH THE MID MORNING HOURS 20-30 POPS WILL BE MAINLY ACROSS THE WRN MTNS AND EAST OF THE SUSQ VALLEY...IN CLOSE PROXIMITY TO A QUASI STNRY FRONT NEAR THE NY BORDER...AND A BACKDOOR FRONT EXTENDING FROM THE ENDLESS MTNS OF NERN PENN...SOUTH TO THE LOWER SUSQ VALLEY. VSBYS IN THE PATCHY FOG WILL BE GENERALLY 1/2SM OR SLIGHTLY GREATER...THANKS TO THE PERIODS OF CLOUDS...AND A LIGHT SSWRLY BREEZE ACROSS CENTRAL AND NRN PENN /WHERE MOST OF YESTERDAY/S RAIN FELL/. A VERY NARROW...FEW DEG F SFC TEMP/DWPT SPREAD WILL MEAN LOW TEMPS MAINLY IN THE LOWER TO MID 60S. A FEW SPOTS ACROSS THE NRN MTNS COULD DIP INTO THE U50S. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SATURDAY/...
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TODAY LOOKS LIKE IT MIGHT BE THE LAST DAY WITH WIDESPREAD AREAS OF SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE REGION. THE SREF AND NAM CONTINUE TO SHOW A WEDGE OF RELATIVELY LOW PW IMPLYING THE MOISTURE WILL HAVE TO REWORK ITSELF INTO THE REGION. THE SREF AND NAM ARE SLOW TO BRING CAPE OF ANY NOTE BACK INTO THE REGION UNTIL THE AFTERNOON HOURS AND AS FORECAST...THE CAPE THIS AFTERNOON LOOKS LESS IMPRESSIVE THAN WE HAD YESTERDAY. NOT SURPRISINGLY...THE MODELS ARE NOT AS WET AND WANT TO FOCUS THE RAINFALL AND MORE SIGNIFICANT RAINFALL TO OUR SOUTH AND WEST. KEPT HIGHER POPS IN SOUTH AND WEST AND FOCUSED POPS LATER IN DAY. WITH THE SURGING HIGH TO OUR NORTHEAST AND LOWER PW HEADED OUR WAY THE FRONTAL BOUNDARY SHOULD BE FARTHER TO THE SOUTH AND WEST.
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&& .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... SOME LINGERING SHOWERS FRIDAY NIGHT. THE SREF IS GETTING REALLY OPTIMISTIC FOR RIDGING COMING INTO THE REGION OVERNIGHT FRIDAY INTO SATURDAY. POPS SHOULD SLOWLY LOWER. SREF NOW THINKS OUR PW VALUES DROP TO AT LEAST NORMAL SATURDAY AND THE BOUNDARY BEGINS A MORE PRONOUNCED SOUTHWARD SHIFT. UPDATED FULL LONGER TERM FORECASTS WILL LIKELY TEND FOR A DRIER DAY SATURDAY AND SUNDAY. HELP IS ON THE WAY...A BACKDOOR FRONT FROM THE NW AND LOWER PW VALUES. PREVIOUS: CONVECTION SHOULD DIMINISH AND PUSH SOUTH OF THE STATE FRIDAY NIGHT...AS SHORTWAVE DIVES SOUTH OF THE AREA. BEHIND THIS FEATURE...BACKDOOR COLD FRONT IS PROGGED TO WORK SWRD THRU CENTRAL PA LATE FRIDAY NIGHT...EARLY SATURDAY. MOIST EASTERLY FLOW ASCENDING THE APPALACHIANS COULD PRODUCE LOW CLOUDS AND SPOTTY DRIZZLE TO LIGHT RAIN FRIDAY NIGHT INTO SATURDAY. THE LARGE UPPER LEVEL LOW SHOULD STAY QUASI-STATIONARY AS THE UPPER LEVEL RIDGE OVER THE MIDWEST WILL CONTINUE BUILD AND TILT OVER THE NORTHEAST THROUGH THE WEEKEND. THE LOW MOVING UNDERNEATH THE RIDGE SHOULD ALLOW FOR A SLIGHT CHANCE FOR SHOWERS SATURDAY INTO SATURDAY NIGHT. 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 /06Z FRIDAY THROUGH TUESDAY/...
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VERY MOIST LLVL ATM WITH SFC DEWPOINTS 65F+ COMBINED WITH LGT WINDS SHOULD SUPPORT WDSPRD REDUCED CIGS AND VSBYS EARLY THIS MORNING. EXPECT GRADUAL IMPROVEMENT THROUGH LATE MORNING WITH VFR CONDS BY THE AFTN. CONCERNING THE CONVECTIVE OUTLOOK...OVERALL CONFIDENCE IS LOW AND COVERAGE SHOULD BE GENERALLY SPARSE - AT IT APPEARS THE MAIN PCPN AXIS WILL BE SHIFTED SWD CLOSER TO WAVY QSTNRY FRONTAL BOUNDARY EXTENDING FROM OH SEWD INTO WV/VA. HOWEVER BRIEF TSTM IMPACTS ARE POSSIBLE BUT ARE BEYOND THE PREDICTABILITY HORIZON AT THIS RANGE. THEREFORE WILL ONLY INCLUDE VCTS AND ALLOW SUBSEQUENT TAF PACKAGES TO REFINE FCST AS NECESSARY. A LARGE AREA OF HIGH PRES WILL BUILD SWWD FROM ERN CANADA INTO THE NORTHEAST AND DOWN THE EAST SIDE OF THE APPLCHNS THIS WEEKEND. EASTERLY FLOW TO THE SOUTH OF THE HIGH SHOULD LEAD TO LOW CLOUDS AND LIGHT RA/DZ FOR THE FIRST PART OF THE WEEKEND BEFORE CONDS IMPROVE INTO EARLY NEXT WEEK. OUTLOOK... SAT...AM LOW CIGS/FOG/DZ/LGT RAIN. SUN...AM LOW CIGS PSBL..BCMG VFR. MON-TUE...VFR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/LAMBERT NEAR TERM...GRUMM/LAMBERT SHORT TERM...GRUMM/LAMBERT LONG TERM...FITZGERALD/CERU AVIATION...DEVOIR/STEINBUGL

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