Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 201512 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1112 AM EDT WED AUG 20 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... A BROAD ZONE OF WEAK-MODERATE CYCLONIC FLOW ALOFT WILL PERSIST FROM THE UPPER MIDWEST/OH VALLEY TO THE APPALACHIANS...TO THE SOUTHEAST OF A WEAKENING DEEP-LAYER H5 LOW OVER THE GREAT LAKES. A MOIST SSWLY FLOW BENEATH A DIFFLUENT EXIT REGION OF MID/UPPER JET ROTATING AROUND THE GREAT LAKES UPPER LOW WILL CONTRIBUTE TO WEAK INSTABILITY AND GENERAL INCREASE IN SHOWERS/TSTMS THRU THE AFTN. AT THE SFC...A FRONTAL BOUNDARY WILL PUSH SLOWLY EWD FROM THE UPPER OH VLY ALONG WITH A RIBBON OF HIGH PWS /1.50-1.75 INCHES/. THE COMBINATION OF SUFFICIENT LG SCALE LIFT...WEAK DESTABILIZATION AND DEEP MSTR/HIGH PWS/60-65+ SFC DEWPOINTS WILL SUPPORT ENHANCED RISK FOR HEAVY-EXCESSIVE RAFL WITH LOCALIZED RUNOFF/FF ISSUES POSSIBLE - ESP IN TRAINING SW-NE ORIENTED BANDS. THE HIRES MDL GUIDANCE GENERALLY SHOWS THIS THREAT WITH 2"+ PT AMTS OVER A SHORT DURATION. A FEW STRONGER STORMS MAY ALSO PRODUCE BRIEF WIND GUSTS MAINLY BELOW SVR LIMITS. HAVE UPDATED THE HWO TO HIGHLIGHT SHORT DURATION HEAVY RAIN/FF THREAT AND SPC D1 SEE TEXT OUTLOOK/5% SVR PROBS. HAVE ALSO ADDED MENTION OF +RA INTO THE TEXT FORECAST. EARLY CLOUDS SHOULD GIVE WAY TO SOME PEAKS OF SUN LATER TODAY AND ALLOW TEMPS TO CLIMB TO NEAR SEASONAL NORMS...WITH HIGHS FROM THE M70S OVR THE HIGH TERRAIN OF THE ALLEGHENIES TO THE M80S ACROSS THE LOWER SUSQ VALLEY. MOIST AIRMASS WILL KEEP MINS IN THE L-M 60S. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM THURSDAY/... FOCUS OF DWINDLING SHRA/TSRA WILL SHIFT TO THE EASTERN COUNTIES THIS EVENING ALONG AXIS OF WEAKENING LL JET/PLUME OF HIGHER PWATS. AFTER A LULL IN THE ACTIVITY THU AM...ANOTHER ROUND OF CONVECTION IS EXPECTED THURSDAY AFTERNOON AS UPPER TRACKS NORTH OF THE STATE. STEEP LPS RATES CAUSED BY COOL POOL ALOFT WILL PROMOTE WIDESPREAD AFTN CONVECTION...ESP ACROSS THE N MTNS. HAVE BUMPED POPS UPWARD TO THE LIKELY CATEGORY ACROSS MOST OF CENTRAL PA BASED ON LATEST GEFS/CONSALL. GEFS 925 TEMPS IMPLY ANOTHER DAY OF NEAR SEASONAL TEMPS WITH HIGHS FROM THE M70S TO M80S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-MON TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUES WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... MVFR CIGS OVR ERN SXNS SHOULD IMPROVE TO LOW VFR BY THIS AFTN. EXPECT SHOWERS/TSTMS TO INCREASE IN COVERAGE OVER THE CNTRL AND ERN PRTNS OF THE AIRSPACE THRU THE AFTN...WITH PERIODS OF IFR VISBYS LKLY IN +RA/+TSRA. OUTLOOK... THU-SUN...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT CHC OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SUN...MAINLY VFR. STILL CHANCE OF SHRA IN THE MORNING. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...FITZGERALD/STEINBUGL SHORT TERM...FITZGERALD LONG TERM...FITZGERALD AVIATION...STEINBUGL

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