Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 021140 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 740 AM EDT THU JUL 2 2015 .SYNOPSIS... RAINFALL SHOULD FOCUS TO THE SOUTH OF PENNSYLVANIA THROUGH THE END OF THE WEEK...NEAR A CONVECTIVELY ACTIVE QUASI-STATIONARY FRONTAL BOUNDARY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA ON SATURDAY ACCOMPANIED BY THE GREATEST RISK FOR SHOWERS FOR INDEPENDENCE DAY. A DRIER WEATHER PATTERN SHOULD BRIEFLY VISIT THE REGION EARLY NEXT WEEK BEFORE UNSETTLED CONDITIONS RETURN BY NEXT WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... DEEP LAYER MOISTURE GRADIENT LIES ACROSS THE MASON DIXON LINE THIS MORNING...SEPARATING MORE SOUPY 1"+ PW FROM SUB 0.75" PW ACROSS NORTH CENTRAL PA. MEAN UPPER TROF LIES ACROSS THE REGION THIS MORNIGN AND AFTERNOON WITH WEAK SHEAR AXES TRACKING ALONG AND SOUTH OF THE PA/MD BORDER. AN AREA OF SHOWERS OVER NORTHERN VA AND NORTHERN MD WILL BRUSH SOUTHERN BORDER COUNTIES OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY THROUGH MID MORNING. EXPECT ISOLD TO SCT CONVECTIVE DEVELOPMENT LATER ON IN THIS SAME AREA. WITH LITTLE TO NO BOUNDARY LAYER FLOW OR SFC MOISTURE CONVERGENCE...CONVECTIVE INITIATION SHOULD OCCUR TO THE SOUTH OF MY AREA LATER TODAY AND MEANDER ENE ALONG THE MOISTURE GRADIENT...REMAINING MOSTLY ALONG AND SOUTH OF THE MASON DIXON LINE. LATEST HRRR RUN DOES GENERATE A CLUSTER OF SHOWERS WITH ISOLATED THUNDER THAT CLIPS THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY THIS AFTERNOON. CONVECTION DIES DOWN BY 02Z WITH FAIR CONDITIONS OVERNIGHT AND SOME LATE NIGHT VALLEY FOG...ESPECIALLY SOUTH. NUDGED POPS UP SLIGHTLY ALONG THE MASON DIXON LINE FOR THIS AFTERNOON WHILE KEEPING NRN AREAS MAINLY DRY THANKS TO THE LOWER PW AIR TO THE NORTH. DAYTIME TEMPS RANGING FROM THE LOWER 70S NORTH TO THE LOWER 80S SOUTHEAST ARE BELOW NORMAL FOR EARLY JULY BUT THE LOWER HUMIDITY IS WELCOME. MINS TONIGHT WILL BE CHILLY IN THE NORTH WITH READINGS IN THE 40S...AND RANGING FROM THE 50S TO THE LOWER 60S ACROSS CENTRAL AND SOUTHEAST PA RESPECTIVELY. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... SHORTWAVE ROUNDING BASE OF UPPER TROF OVR THE MIDWEST WILL CAUSE QUASI-STATIONARY FRONT TO BUCKLE NORTHWARD LATE FRIDAY AS ASSOC SFC WAVE LIFTS NE FROM THE OHIO VALLEY. LOW LVL EASTERLY WIND/PWAT ANOMALIES IN GEFS OUTPUT TARGET THE S TIER COUNTIES FOR A CHC OF SHOWERS...ESP DURING THE PM HOURS. MDL SOUNDINGS EVEN INDICATE A BIT OF ELEVATED INSTABILITY...IMPLYING TSRA POSS ACROSS THE LAURELS/SC MTNS. DRIER AIR MASS ASSOC WITH HIGH PRES OVR UPSTATE NY SHOULD KEEP THE NORTHERN HALF OF THE STATE DRY FRI/FRI NIGHT. GEFS MEAN 925MB TEMPS BTWN 18-20C SHOULD SUPPORT FAIRLY UNIFORM MAX TEMPS IN THE M-U70S. CONSALL OUTPUT INDICATING MIN TEMPS FRI NIGHT IN THE U50S-L60S FROM NORTH TO SOUTH. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... DESPITE MINOR TIMING DIFFERENCES AMONG MED RANGE MDLS...THE OVERALL PATTERN APPEARS FAIRLY CERTAIN. MEAN UPPER LVL TROF WILL REMAIN CENTERED WEST OF PA...RESULTING IN REGULAR OPPORTUNITIES FOR RAIN. ECENS/GEFS INDICATE THE BEST CHC FOR SHOWERS WILL ACCOMPANY PASSAGE OF SHORTWAVES SAT AND WED. LATEST GUIDANCE SUGGESTS SCT SHOWERS SAT WILL BE LIGHT AND CONCENTRATED VERY EARLY IN THE DAY...AS DEEP MOISTURE REMAINS SOUTH OF THE BORDER AND WAVE PASSES EAST OF THE STATE BY MIDDAY. WILL MAINTAIN A SLIGHT CHC OF DIURNALLY-DRIVEN CONVECTION SUN-TUE...DUE TO MDLS DEPICTION OF A WEAK CUT OFF UPPER LOW OVR THE CENTRAL APPALACHIANS. HOWEVER...DEEP MOISTURE AND OPPORTUNITY FOR MEANINGFUL RAINFALL SHOULD HOLD OFF UNTIL APPROACH OF COLD FRONT AND POSITIVE PWAT ANOMALIES WED. GEFS/ECENS OUTPUT IMPLY TEMPS FAIRLY CLOSE TO AVERAGE FOR EARLY JULY. SAT IS LIKELY TO BE A BIT COOL DUE TO CLOUD COVER/SCT SHOWERS AND LINGERING LL EASTERLY FLOW. HOWEVER...SW FLOW IN ADVANCE OF AN APPROACHING COLD FRONT IS LIKELY TO PUSH TEMPS A BIT ABV AVERAGE BY TUE/WED OF NEXT WEEK. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... LGT WINDS AND RESIDUAL LLVL MSTR WILL PROMOTE SOME RESTRICTIONS EARLY THIS MORNING...WITH IMPROVEMENT TO VFR EXPECTED BY 14-15Z. NARROWING T/TD SPREADS FAVORS 09-12Z TIMING OVER CENTRAL AND SRN AIRFIELDS...WHILE BFD SHOULD BE TRENDING TO THE UPSIDE. VFR WILL PREVAIL THROUGH THE AFTERNOON WITH A VERY LOW RISK FOR AN ISOLD SHOWER/TSTM OVER THE EXTREME SRN AIRSPACE...NEAR FRONTAL ZONE POSITIONED TO THE SOUTH OF PA/MD BORDER. EXPECT ANY PCPN TO BE CONFINED OVER THE FAR SRN AIRSPACE INTO TONIGHT AS LOW PRESSURE WAVE TRACKS ENEWD FROM THE TN VLY INTO THE DELMARVA. OUTLOOK... FRI...VFR/MVFR WITH CHC OF SHOWERS OVER THE SRN 1/3 OF AIRSPACE. SAT...VFR/MVFR WITH CHC OF SHOWERS. SUN-MON...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...DEVOIR SHORT TERM...FITZGERALD LONG TERM...FITZGERALD/CERU AVIATION...STEINBUGL

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