Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221746 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 146 PM EDT TUE JUL 22 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE COMMONWEALTH LATE WEDNESDAY AND WEDNESDAY NIGHT. A REFRESHING COOLER AND LESS HUMID AIRMASS WILL OVERSPREAD THE COMMONWEALTH FOR THE END OF THE WEEK INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... CONVECTIVE MIXING HAS LED TO THE DEMISE OF THE LOW CLOUD SHIELD...BUT NOW WE ARE SEEING MORE CUMULUS FORM. SATELLITE AND RADAR INDICATE A COUPLE OF SMALL SHOWERS TRYING TO GET GOING IN THE WARM HUMID AIRMASS...BUT THE WARM DRY AIR ALOFT IS SO FAR KEEPING ACTIVITY MAINLY CAPPED. MESO ANAL SHOWS A TONGUE OF MUCAPES EXCEEDING 2000J NOSING INTO SWRN PA BUT ALSO INDICATES VERY WARM MID LEVEL AIR PUSHING INTO THE AREA. THIS WILL HELP SUPPRESS ACTIVITY DESPITE THE EXPECTATIONS OF A FAIR AMOUNT OF AVAILABLE INSTABLITY THIS AFTERNOON. THE BEST CHC FOR THE ISOLATED CONVECTION WOULD SEEM TO BE OVER SOUTHERN AREAS EAST TO THE LOWER SUSQ VALLEY WHERE SLIGHTLY COOLER MID LEVEL TEMPS ARE FORECAST TO PERSIST. AFTERNOON HIGHS WILL BE NOTICEABLY WARMER THAN PREVIOUS DAYS...TOPPING OUT NEAR 90 OVER THE SE AND IN THE MID 80S OVER THE NW. THE OVERNIGHT WILL BE SIMILAR TO LAST NIGHT...DRY BUT WITH PATCHY LOW CLOUDS AND FOG FORMING AFTER MIDNIGHT. IT WILL BE A HUMID NIGHT FOR SLEEPING. && .SHORT TERM /WEDNESDAY/... A DRY START TO THE DAY WEDNESDAY WILL GIVE WAY TO INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS AS FORCING INCREASES ASSOCIATED WITH THE APPROACHING COLD FRONT. WE ARE NOT OUTLOOKED FOR SEVERE AT THIS TIME BUT THE AIRMASS CHANGE WILL BE FAIRLY STARK FOR MID JULY AND FORECAST CAPES IN EXCESS OF 1200J SUGGEST SPC MIGHT EXPAND THEIR SLIGHT RISK WITH LATER UPDATES. EITHER WAY IT LOOKS LIKE AN UNSETTLED AND WET DAY AS THE FRONT TRAVERSES THE REGION. THANKS TO A WARMING LOW LEVEL WSW DOWNSLOPE FLOW AHEAD OF THE CFRONT...HIGH TEMPS WED WILL BE THE WARMEST OF THE WEEK...RANGING FROM THE LOWER 80S ACROSS THE HIGHEST TERRAIN OF THE NORTH AND WEST...TO THE MID AND UPPER 80S IN THE CENTRAL VALLEY...AND LOWER 90S IN THE GREATER YORK/HARRISBURG AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... OVERALL SCENARIO REMAINS UNCHANGED IN THE LONG TERM PERIOD AS A LARGE UPPER RIDGE BUILDING OVER THE FOUR CORNERS REGION IS FORECAST TO EXPAND NORTH AND EAST INTO THE ROCKIES AND PLAINS DURING THE PERIOD. DOWNSTREAM...THIS WILL LEAD TO LONG WAVE TROFFING OVER THE EASTERN THIRD OF THE COUNTRY. UPPER LOW TO THE EAST OF HUDSON BAY WILL BE STRENGTHENED AT TIMES BY SHORTWAVE ENERGY IN THE STRONGER JET STREAM FLOW ACROSS CANADA. SOUTHWARD EXTENSION OF THIS LOW/TROF WILL AT TIMES DURING THE PERIOD STRENGTHENING THE TROFFING ACROSS THE NORTHEASTERN U.S./OUR REGION. TODAYS TREND OF MEDIUM RANGE MODEL GUIDANCE IS FOR STRONGER/DEEPER TROFFING DOWNSTREAM ACROSS THE EASTERN U.S...DEVELOPING AN ALMOST FULL LATITUDE TROF EXTENDING FROM THE EASTERN CANADA LOW SWD TO FLORIDA. THIS WILL LIKELY SERVE TO EXPAND AND PROLONG THE CHANCES FOR PCPN THIS WEEKEND. GUIDANCE FORECASTS CONTINUE TO BRING A FRONT AND INCREASED CHANGES FOR PRECIPITATION TOWARD PA IN THE WEDNESDAY/THURSDAY TIME FRAME AND SHOW A SECOND...POTENTIALLY STRONGER SYSTEM LATE NEXT WEEKEND. THE TREND OF STRONGER TROUGHING MENTIONED ABOVE HAS LEAD TO SLOWER ARRIVAL AND DEPARTURE OF THE FRONTAL SYSTEM IN THE DAILY PROGS. A WARM FRONT WILL BE ON THE DOORSTEP OF PA SUNDAY MORNING...A BIT SLOWER THAN FORECAST YESTERDAY. HAVE THUS ADJUSTED POPS/TIME TO SUIT. ASSOCIATED COLD FRONT DOES NOT CROSS THE STATE TIL MONDAY AT THIS POINT...LEADING TO A POTENTIAL PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS. AT THIS TIME FRAME HOWEVER...A LOT WILL LIKELY CHANGE BEFORE WE REACH NEXT WEEKEND. && .AVIATION /17Z TUESDAY THROUGH SATURDAY/... ALL TERMINALS ARE VFR AT THIS HOUR...AND WILL REMAIN INTO THE EVENING. WARMING TEMPS ALOFT AND LACK OF STRONG FORCING SUGGESTS VERY LOW CHANCES OF AFTERNOON POP-UP SHOWERS OR THUNDERSTORMS. NO MENTION OF THUNDERSTORMS IN TAFS AS POINT PROBS/PCPN CVRG WILL BE VERY LOW/SPARSE. THE BEST CHANCE OF A SHOWER OR THUNDERSTORM WILL BE SOUTH OF I-80 INTO THE EVENING. DIURNAL CU SHOULD FADE AFTER DARK WITH SOME PATCHY FOG AND ASSOCD LOWER CIGS/VIZ RE-DEVELOPING OVERNIGHT. WEDNESDAY WILL FEATURE A STRONG COLD FRONT PASSING THROUGH THE AREA ALONG WITH NUMEROUS SHOWERS AND THUNDERSTORMS. TERMINALS WILL BE MAINLY VFR BUT WITH IMPACTS INCREASING ALONG WITH THE COVERAGE OF THE SHOWERS AND STORMS..ESPECIALLY IN THE AFTERNOON AND EVENING. OUTLOOK... THU...SCT TSTM IMPACTS PSBL SERN AIRFIELDS AS COLD FRONT SLOWS ALONG THE MID-ATLC COAST. FRI-SAT...PATCHY A.M. FOG. OTHERWISE NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE

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