Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 231959 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 359 PM EDT WED JUL 23 2014 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE COMMONWEALTH THIS EVENING AND TONIGHT. A REFRESHING...COOLER AND LESS HUMID AIRMASS WILL OVERSPREAD THE COMMONWEALTH FOR THE END OF THE WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... A FEW TOWERS HAVE BROKEN THE CAP. HOWEVER...WARM AIR ALOFT IS SUPPRESSING MORE-WIDESPREAD TSRA FOR NOW. PARAMETERS FOR SEVERE ARE RATHER WEAK AND SPC OUTLOOK IS ONLY FOR VERY SMALL CHC OF SVR WIND/HAIL. NOT MUCH SHEAR - WITH THE HIGHEST AMOUNTS TO THE N/E. CAPES ARE HIGH IN THE CELLS THAT ARE BIG ENOUGH TO BREAK THE CAP...SO PULSE STORMS AND VERY TRANSIENT/SHORT-LIVED SVR THREAT IS WHAT IS EXPECTED THIS EVENING. NOT MUCH ORGANIZATION TO THE CELLS YET...WITH THE TERRAIN SEEMINGLY THE GENESIS FOR THE FIRST CUSTOMERS OF THE DAY. EXPECT THE SHOWERS/STORMS TO COVER MORE OF THE RADAR SCOPE SHORTLY...WITH MUCH OF THE AREA SEEING A LITTLE RAIN BEFORE THE EVENING IS OVER. THE COLD FRONT HAS MOVED ONSHORE FROM LAKE ERIE AND IS PRACTICALLY TO KBFD AT 1830Z. DRY AIR BEHIND IT IS ALSO COOLING THE LOCATIONS ALONG THE LAKESHORE. THIS SHOULD PUT AN END TO SHOWERS FOR THE NW AS IT MOVES TO THE SE THROUGH THE EVENING. LATEST MESO GUIDANCE AGREES ON THE SPEED AND PROGRESSION OF THE SH/TSRA THIS EVENING. THERE COULD BE A LIGHT SHOWER OR TWO POP UP AS LITTLE POCKET OF COOLER AIR ALOFT MOVES THROUGH NY STATE AND BRUSHES THE NRN TIER A FEW HOURS AFTER THE COLD FRONT GOES BY. EXPECT ALMOST ALL SHOWERS TO BE TO THE S OF IPT/UNV/JST BY 00Z. SOME SHOWERS WILL PROBABLY LINGER THROUGH MIDNIGHT IN THE SERN COS/SRN TIER. BUT COVERAGE DIPS QUICKLY AFTER SUNSET. && .SHORT TERM /MIDNIGHT THROUGH 6 PM THURSDAY/... AS THE STORMS DIE OFF AND MOVE TO THE SOUTH...LOWER CLOUDS WILL ENTER THE PICTURE FROM THE N/W. LATEST MODEL GUIDANCE IS NOW JUMPING ON-BOARD WITH THE NAM IS PUSHING THE DRY AIR AND SHOWERS OFF TO THE S OF THE MASON-DIXON LINE EARLY TONIGHT. CONTINUITY BETWEEN MOST FCSTS HAS BEEN STRONG WITH SOME SHRA LINGERING IN THE SRN TIER THROUGH THE NIGHT. SO WILL CONTINUE ON WITH THAT SLIGHT CHC POP THERE...BUT DRY IT OUT AFTER SUNRISE THURSDAY. THE GUIDANCE TEMPS TONIGHT DO DROP NICELY OVER THE NORTH - BUT WILL TEMPER THAT FALL DUE TO THE ANTICIPATED LOWER CLOUD DECK THERE. MID 50S SHOULD BE LOW ENOUGH EXCEPT FOR THE MOST RURAL VALLEYS. THUS...THERE COULD BE A BIT OF VALLEY FOG TONIGHT...BUT THE AIR IS VERY DRY. WILL THEREFORE NOT MENTION FOG FOR TONIGHT IN THE GRIDS. THURSDAY SEEMS LIKE A GREAT DAY FOR ANY OUTDOOR ACTIVITY WITH ANY LOW CLOUDS BURNING AWAY IN THE MORNING. HIGHER CLOUDS ALONG THE SRN BORDER MAY LINGER FOR A BIT LONGER...BUT NOT ENOUGH TO WARRANT A MOSTLY CLOUDY FCST. DESPITE THE 8H TEMPS AS LOW AS +10C IN THE MORNING ACROSS THE NORTHERN TIER...EVEN THEY SHOULD WARM BACK INTO THE LOWER/MID 70S. 80F AND MAYBE A LITTLE WARMER IS EXPECTED IN THE SOUTH. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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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 MODERATE TO STRONG 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. CONDS WILL BE IMPROVING AT THE START OF THE PERIOD AS COLD FRONT EXITS. A SECOND...POTENTIALLY STRONGER SYSTEM WILL AFFECT THE REGION 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.
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&& .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... SCT TO NMRS TSRA SHOULD CONTINUE THROUGH 00Z...MOVING STEADILY TO THE EAST AND SOUTH. MOST STORMS SHOULD BE OFF THE THE SE OF SEG/AOO BY 00Z AND THROUGH LNS BY 04Z AS A COLD FRONT PUSHES STEADILY SE THROUGH THE AREA. CIGS SHOULD BE VFR FOR MUCH OF THE TIME THIS EVENING. WINDS ARE OUT OF THE WEST BEFORE THE FRONT WHICH IS ON TOP OF KBFD AT 1845Z. BUT THE WIND PROFILE IS NOT A SET UP FOR STRONG GUSTS UNLESS A STORM GROWS VERY TALL THIS EVENING. LOW MVFR AND EVEN SOME IFR CIGS WILL BE FOUND IN THE NWRN HALF OF THE AREA TONIGHT AS THE COOLER AIR MOVES IN. FOG IS NOT ANTICIPATED TO BE IFR TONIGHT...BUT MANY OF THE VALLEYS OF THE NORTH COULD GET SOME FOG. WILL ONLY MENTION MVFR FOG IN A FEW LOCATIONS. THE DRYNESS OF THE AIR WILL WIN OUT AFTER SUNRISE ON THURSDAY...BREAKING THE CLOUDS UP. VFR SHOULD BE THE WORD FOR THURSDAY INTO SATURDAY. JUST THE NRN VALLEYS WILL DROP COLD ENOUGH TO MAKE THE FOG HAPPEN EACH NIGHT. OUTLOOK... FRI...PATCHY MORNING FOG...OTHERWISE VFR/NO SIG WX. SAT...PATCHY MORNING FOG...OTHERWISE VFR. PM TSRA/MVFR POSS W. SUN-MON...SHRA/TSRA AS WARM FRONT THEN COLD FRONT MOVE THROUGH. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...LAMBERT/GARTNER AVIATION...DANGELO

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