Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 230129 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 929 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 /UNTIL 6 AM WEDNESDAY MORNING/...
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WARM MID LEVEL LAYER KEPT CONVECTION LARGELY AT BAY THIS EVENING WITH ISOLATED ACTIVITY OVER MAINLY THE LAUREL HIGHLANDS WITH SHALLOW CUMULUS BUILDUPS ELSEWHERE. FINAL REMNANTS OF THIS ACTIVITY ARE WEAKENING OVER SOUTHERN HUNTINGDON COUNTY WITH ANOTHER WEAK SHOWER EVIDENT OVER SOMERSET COUNTY. WILL END POPS BY 03Z WITH A DRY OVERNIGHT EXPECT. PATCHY LOW CLOUDS AND FOG WILL FORM AFTER MIDNIGHT...SIMILAR TO TUE MORNING...AND IT WILL BE RATHER UNCOMFORTABLE FOR SLEEPING WITH SFC DEWPOINTS RANGING FROM THE MID 60S NORTH...TO THE UPPER 60S TO LOWER 70S ELSEWHERE.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM 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. THE 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. THE ECMWF IN LATEST RUN HAS SLOWED UP THE PROGRESSION OF THIS UPPER LEVEL LOW...WHERE THE GFS OPERATIONAL AND ENSEMBLES HAVE SPED UP ITS PROGRESSION THROUGH THE GREAT LAKES REGION. A WARM FRONT WILL BE ON THE DOORSTEP OF PA SUNDAY...AS THE EC CONTINUES TO SLOW ITS PROGRESSION SO EXPECT THE WARM FRONT TO MOVE IN CLOSER TO MIDDAY SUNDAY. HAVE THUS ADJUSTED POPS/TIME. ASSOCIATED COLD FRONT DOES NOT CROSS THE STATE TIL MONDAY...WHERE SURPRISINGLY AT THIS POINT...THE EC AND GFS COME CLOSELY IN PHASE. THIS LARGE UPPER LEVEL LOW COULD BECOME QUASI STATIONARY OVER SOUTHERN CANADA...GREAT LAKES REGION WHICH COULD LEAD TO A POTENTIAL PROLONGED PERIOD OF SHOWERS AND THUNDERSTORM THROUGH THE MIDDLE OF NEXT WEEK. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS ACROSS CENTRAL PENNSYLVANIA EARLY THIS EVENING. RADAR CONTINUES TO SHOW SOME SCATTERED TO ISOLATED SHOWERS ACROSS THE HIGHER ELEVATIONS OF THE WEST...AND THESE MAY AFFECT KJST AND KAOO AIRFIELDS THROUGH AROUND 02Z. REMAINING DIURNAL CU SHOULD FADE AFTER DARK WITH SOME PATCHY FOG AND ASSOCIATED LOWER CIGS AND VSBYS RE-DEVELOPING OVERNIGHT. MOST SUSCEPTIBLE FOR LOWER IFR CONDITIONS WOULD BE AT KBFD...WITH MOST OTHER LOCATIONS FORECAST TO REMAIN GENERALLY IN THE MVFR CATEGORY. WEDNESDAY WILL FEATURE A STRONG COLD FRONT PASSING THROUGH THE AREA ALONG WITH NUMEROUS SHOWERS AND THUNDERSTORMS. TERMINALS WILL BE MAINLY VFR...WITH MENTION OF VCSH DURING THE LATER MORNING WEST...AND AFTERNOON EAST. WILL WAIT TO SEE WHAT COVERAGE IS BEFORE PAINTING IN CATEGORICAL RESTRICTIONS. OUTLOOK... THU...SCT TSTM IMPACTS PSBL SERN AIRFIELDS AS COLD FRONT SLOWS ALONG THE MID-ATLC COAST. FRI-SAT...PATCHY MORNING FOG...OTHERWISE NO SIG WX. SUN...POSSIBLE RESTRICTIONS AS SHRA/TSRA MOVE BACK INTO THE AREA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...DEVOIR/LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/CERU AVIATION...JUNG/LA CORTE

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