Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 270136 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 936 PM EDT TUE AUG 26 2014 .SYNOPSIS... HIGH PRESSURE WILL YIELD TO A COLD FRONT THAT WILL SAG THROUGH THE REGION WEDNESDAY. DRY WEATHER WITH LOW HUMIDITY...AND TEMPERATURES SEVERAL DEGREES BELOW NORMAL WILL RETURN FOR LATE WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... CLEAR SKIES PREDOMINATE THIS EVENING...AS UPPER RIDGE AND 590+ DM 500 MB HEIGHTS COVER THE SOUTHWEST HALF OF CENTRAL PA THIS EVENING. CONVECTIVE DEBRIS THE UPPER RIDGE FLATTENS OVER THE EASTERN GLAKS OVERNIGHT IN RESPONSE TO FAST MOVING SHORTWAVE TROF EMBEDDED IN ZONAL FLOW EJECTING FROM THE CANADIAN ROCKIES THIS AFTERNOON...WHICH REACHES LAKE SUPERIOR BY 12Z WED MORNING. AS A RESULT...EVENING CLEAR SKIES WILL GRADUALLY BE OVERTAKEN BY INCREASING CLOUDS FROM NORTHWEST TO SOUTHEAST BEGINNING LATER THIS EVENING OVER THE NORTHWEST MOUNTAINS...WITH MOSTLY CLOUDY CONDITIONS REACHING THE CENTRAL MOUNTAINS BY 12Z. MINS WILL CORRESPONDINGLY BE A FEW DEGREES WARMER THAN TUE MORNING READINGS. HOWEVER...INITIALLY CLEAR SKIES AND LIGHT WINDS WILL PROMOTE THE DEVELOPMENT OF AREAS OF VALLEY FOG...GENERALLY AFTER MIDNIGHT. MIN TEMPS WILL BE NEAR 60. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... SHORT TERM OPERATIONAL MODELS AGREE IN SAGGING A COLD FRONT DOWN THROUGH THE FORECAST AREA DURING THE DAY WEDNESDAY. THE DWINDLING RIBBON OF ANOMALOUSLY HIGH PWAT AIR INDICATES THE FRONT WILL BE WEAK AND WEAKENING FURTHER AS IT MOVES THROUGH. MAIN CONCERN WILL BE FOR CONVECTION WHICH SEEMS LIKE IT WILL HAVE SOME CAPE TO WORK WITH. THE WIND FIELDS ARE FORECAST TO BE WEAK...SO THE SEVERE THREAT SHOULD NOT BE WIDESPREAD...BUT CANNOT RULE OUT A STRONG WIND GUST OR SOME MARGINALLY SEVERE HAIL IN SOME OF THE MORE ROBUST UPDRAFTS. OPERATIONAL NAM COOKS UP CAPES IN EXCESS OF 2000J WHILE THE SREF AND GEFS ARE MORE MODEST...BUT STILL NOT NEGLIGIBLE. IT WILL BE ANOTHER VERY WARM DAY WITH HIGHS POSSIBLY NUDGING 90 FOR THE LAST TIME THIS SEASON OVER THE SERN PART OF THE FCST AREA. THE BULK OF THE REMAINDER OF THE AREA WILL REACH 80 OR ABOVE. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER RIDGE IS FORECAST TO SURGE NWD ALONG THE EAST COAST INTO THE EARLY WEEKEND AS SHORTWAVE ENERGY SUPPORTING WEDNESDAY FROPA LIFTS OUT. THIS RIDGING...ACCOMPANIED BY HIGH PRESSURE SLIDING ACROSS NEW ENGLAND WILL BRING A RETURN TO DRY CONDITIONS FOR LATE THIS WEEK. AS THE HIGH MOVES OFF OF THE COAST RETURN SLOW WILL HELP PULL THE FRONT FROM EARLIER IN THE WEEK NORTHWARD INTO WESTERN PA ON SATURDAY. AFTERNOON HIGH TEMPS NEAR NORMAL ON FRIDAY WILL SURGE TO 5 TO 10 DEGREES ABOVE NORMAL OVER THE WEEKEND. NEXT SHORTWAVE TROF IN THE NORTHERN STREAM FLOW IS PROGGED TO EMERGE FROM THE PLAINS ON FRIDAY AND LIFT TO EASTERN ONTARIO BY SUNDAY. THIS WILL SUPPORT A COLD FRONT REACHING NRN PA ON SUNDAY. MODEL TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THE FRONT AND TO TALL THE SOUTHWARD PROGRESS OF THE FRONT AS SUPPORTING SHORTWAVE ENERGY SHEARS NEWD. CURRENT TIMING PLACES THE FRONT OVER NORTHWEST PA ON MONDAY WITH A SFC WAVE RIDING ALONG THE FRONT...AND THE FRONT LIFTING NORTH OF THE STATE BY TUESDAY. THIS SLOWER...LESS AGGRESSIVE SCENARIO WILL KEEP SCATTERED SHOWERS/TSRA IN THE FORECAST FOR THE WEEKEND...BUT IS LESS UNSETTLED FOR THE HOLIDAY WEEKEND THAN PREVIOUS THINKING. CLOUDY CONDS ON MONDAY WILL BRING MAX TEMPS BACK TO WITHIN A COUPLE DEGREES OF NORMAL AND BELOW NORMAL ON TUESDAY. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
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HIGH CLOUDS DRIFTING INTO NW MTNS ARE ASSOCIATED WITH A BAND OF QUICKLY DIMINISHING CONVECTION /AT 02Z/ OVER NE OHIO. OTHERWISE CLEAR SKIES WILL BE THE RULE FOR CENTRAL PA. LIGHT WINDS WILL AGAIN LEAD TO FORMATION OF LIGHT FOG LATE...WITH LOCALIZED IFR/LIFR DEVELOPING IN SOME VALLEYS IN FOG AND LOW CLOUDS... WHICH WILL BURN OFF BY MID MORNING WED. A COLD FRONT WILL CROSS THE LOWER GREAT LAKES LATE TONIGHT AND MOVE SOUTH THRU THE AIRSPACE DURING THE DAYTIME HOURS ON WED. MODELS INDICATING AN MVFR DECK POSS AT KBFD WED MORNING. SCT SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP ALONG/AHEAD OF THE COLD FRONT...MAINLY IN CENTRAL AND SOUTHERN PA...WITH LOCAL RESTRICTIONS EXPECTED WITH THE CONVECTION. DID NOT MENTION RESTRICTIONS IN TAFS AT THIS TIME DUE TO EXPECTED SCATTERED NATURE OF STORMS. OUTLOOK... THU-FRI...LATE NIGHT-EARLY MORNING RESTRICTIONS IN FOG POSSIBLE...OTHERWISE VFR. SAT-SUN...MAINLY VFR. CHC OF SHOWERS/ISOLD TSTMS.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...DEVOIR/LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...RXR

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