Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 301720 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 120 PM EDT TUE JUN 30 2015 .SYNOPSIS...
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A WARM FRONT WILL MOVE ACROSS THE MIDDLE SUSQUEHANNA AND NORTH CENTRAL MOUNTAINS THIS AFTERNOON. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATER TONIGHT AND WEDNESDAY. THESE TWO WEATHER FEATURES WILL SUPPLY THE FOCUS FOR MOISTURE AND LIFT TO FORM NUMEROUS SHOWERS...AND SCATTERED STRONG TO POTENTIALLY SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING. A PERSISTENT UPPER LVL TROUGH WILL REMAIN POSITIONED JUST WEST OF PENNSYLVANIA THROUGH SATURDAY. AN UPPER LVL RIDGE IS EXPECTED TO BRIEFLY BUILD OVER THE NORTHEAST CONUS SUNDAY INTO MONDAY.
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&& .NEAR TERM /UNTIL 8 PM THIS EVENING/...
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SFC WARM FRONT AT 1645Z EXTENDED FROM NEAR KBFD TO KUNV AND KMUI AND WILL CONTINUE TO LIFT SLOWLY NWD THIS AFTERNOON. LLVL SOUTHERLY 0-1KM SHEAR IS GREATEST OVER THE EASTERN HALF OF PENN...AS IS THE SFC BASED CAPE...WHICH HAS RAMPED UP QUICKLY TO AROUND 2500 J/KG INVOF KTHV AND KLNS WITHIN SOME POCKETS OF PARTLY TO MOSTLY SUNNY SKIES. TRIPLE POINT INTERSECTION OF LEE TROUGH HANGING SOUTH FROM THE WARM FRONT ACROSS THE SUSQ VALLEY WITH LIKELY BE THE PRIMARY THREAT AREA FOR SEVERE WEATHER AND EVEN A FEW NEWD MVG SUPERCELLS THIS AFTERNOON AND EVENING...WHERE EHI/S WILL BE AOA 2M2/S2. SPC RECENTLY BUMPED UP THEIR TORNADO PROB FROM 2 PERCENT TO 5 PERCENT IN THAT AREA SECOND AREA OF CONCERN IS ACROSS THE WESTERN ZONES CLOSES TO THE APPROACHING CFRONT...AND BENEATH THE ENHANCED LIFT/EXIT REGION OF AN 80 KT UPPER JET LIFTING NE FROM WVA. SPC RECENTLY ISSUED SEVERE TSRA WATCH 371 UNTIL 8 PM EDT ACROSS MUCH OF OHIO AND WRN PENN...RIGHT UP AGAINST OUR WRN CWA. BETWEEN THESE TWO AREAS /ACROSS MUCH OF THE CENTRAL MTNS AND WEST BRANCH VALLEYS/...CONVECTION SHOULD BE MORE ISOLATED TO SCATTERED /JUST FOR THE SHORT TIME BEING/ BEFORE THE EXIT REGION OF THE AFOREMENTIONED UPR LVL JET SLIDES EAST ACROSS THESE AREAS. SEVERE TSRA WATCH 372 COMING OUT SHORTLY FOR THE REMAINDER OF CENTRAL AND EASTERN PENN EFFECTIVE UNTIL 9 PM EDT /WITH THE EXCEPTION OF JUST WARREN CTY IN OUR NW CWA/. WEAKER MID LVL WINDS IMPLY LESS CHC OF SVR WX ACROSS THE NW MTNS OF PENN. OTHER AREA OF CONCERN WILL BE THE POSSIBILITY OF LOCALIZED FLOODING...DUE TO WET GROUND AND EXPECTATION OF ISOLD RAINFALL AMTS OF ARND 3 INCHES BASED ON OUTPUT FROM CONVECTION-ALLOWING MDLS. WILL MENTION IN HWO FOR NOW...BUT A FFA COULD BE CONSIDERED FOR THE SUSQ VALLEY...WHERE PLUME OF HIGHEST MOISTURE WILL LIE. PTSUNNY SKIES SHOULD PUSH TEMPS INTO THE M70S OVR THE ALLEGHENIES THIS AFTN...AND THE L80S ACROSS THE SUSQ VALLEY.
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&& .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
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POTENT SHORTWAVE DIVING INTO BASE OF DEEPENING UPPER TROF WILL SWING THRU CENTRAL PA LATE TONIGHT AND EARLY WEDNESDAY. DESPITE AN UNFAVORABLE TIME OF DAY FOR CONVECTION...STRONG LG SCALE FORCING COMBINED WITH MARGINAL INSTABILITY SHOULD SUPPORT SCT SHRA/TSRA AS THIS FEATURE COMES THRU LATE TONIGHT INTO EARLY WED. HAVE REDUCED POPS SIGNIFICANTLY AFTER ABOUT 15Z...AS LG SCALE SUBSIDENCE AND SOMEWHAT DRIER WESTERLY FLOW ARRIVES IN WAKE OF SHORTWAVE. SPC MRGL RISK OF SVR WX ENCOMPASSES EASTERN PA...WHERE THERE COULD BE ENOUGH DIURNAL HEATING/DESTABILIZATION TO SUPPORT ISOLD SVR WX ARND MIDDAY. PTSUNNY SKIES AND ENS MEAN 8H TEMPS BTWN 12-14C SHOULD SUPPORT MAX TEMPS WED FROM THE L70S NW TO M80S LOWER SUSQ VALLEY.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... MED RANGE GUIDANCE CONTINUES TO SHOW A MEAN UPPER LVL TROUGH JUST WEST OF PA INTO EARLY NEXT WEEK...SUPPORTING NUMEROUS OPPORTUNITIES FOR SHOWERS...MAINLY DURING THE PM HOURS. BEST CHANCE OF SHOWERS WILL COME WITH PASSAGE OF SHORTWAVES THU/SAT/MON. HOWEVER...CAN/T RULE OUT A SHRA/TSRA ACROSS THE SW COUNTIES FRI/SUN...IN VICINITY OF STALLED FRONTAL BNDRY. GEFS/ECENS MEAN 8H TEMPS IMPLY TEMPS FAIRLY CLOSE TO AVERAGE FOR EARLY JULY. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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INCREASING COVERAGE OF CONVECTION /SHOWERS AND ISOLATED-SCTD STRONG TO POTENTIALLY SVR TSRA/ WILL OCCUR DURING THE AFTERNOON AND CONTINUE INTO THE EVENING HOURS. MOST AIRFIELDS OUTSIDE OF THE CONVECTION WILL SEE VFR TO UPPER END MVFR WITH A 5-10 KT SW SFC WIND. A SLIGHTLY STRONGER SOUTH TO SSWRLY SFC FLOW OF 10-15 KTS WITH GUSTS AROUND 20 KT WILL PRESIDE ACROSS THE LOWER SUSQ VALLEY /JUST SOUTH OF A SFC WARM FRONT...AND EAST OF A DEVELOING LEE SFC TROUGH/. FLYING CONDITIONS SHOULD SETTLE INTO MAINLY THE MVFR RANGE FOR TONIGHT AS WINDS LIGHTEN AND MOISTURE REMAINS QUITE HIGH WITH SCATTERED SHOWERS AND ISOLATED TSRA ACROSS CENTRAL PENN...AND MORE NUMEROUS SHRA/TSRA IMPACTING THE LOWER SUSQ VALLEY TAF SITES. AN UNSETTLED PATTERN WITH A SERIES OF FRONTS WILL BE AFFECTING THE REGION MUCH OF THIS WEEK. THE BEST CHANCES OF RESTRICTIONS WILL BE TUESDAY INTO WEDNESDAY. OUTLOOK... WED...MVFR CIGS LIKELY WEST. OTHERWISE MAINLY VFR. LOCAL RESTRICTIONS IN SCT SHRA/TSRA. THU...MAINLY VFR. ISOLATED TSRA MAINLY SOUTH OF I-80. FRI...MAINLY VFR. ISOLATED TSRA SOUTH. SAT...MAINLY VFR. CHANCE SHRA/TSRA.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...FITZGERALD LONG TERM...FITZGERALD/CERU AVIATION...LAMBERT

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