Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 060633 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 233 AM EDT MON JUL 6 2015 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL DRIFT SLOWLY EAST OF THE REGION TONIGHT. WARM AND HUMID CONDITIONS WILL MOVE BACK INTO PENNSYLVANIA EARLY IN THE UPCOMING WEEK...BRINGING SEVERAL CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS THROUGH AT LEAST MID WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATE EVENING SATL AND REGIONAL RADAR LOOPS SHOW UPPER LOW LIFTING NE UP THE OHIO RIVER VALLEY NR KHTS. MUCH OF THE EARLIER CONVECTION ASSOC WITH THIS FEATURE WAS DIURNALLY-DRIVEN AND IS DISSIPATING AS IT APPROACHES SOUTHERN PA. WILL CARRY LOW CHC OF SHOWERS THRU 06Z ACROSS ONLY SOMERSET/BEDFORD/FULTON COUNTIES. SITUATION CHANGES TOWARD DAWN...AS LL JET AND ASSOC PLUME OF ANOMALOUS PWATS LIFT INTO SOUTHWEST PA. WILL RAMP POPS UPWARD TO ARND 75 PCT BTWN 06Z-12Z ACROSS THE SOUTHWEST COUNTIES AS THIS FEATURE MOVES IN. CLOUDS WILL GRADUALLY THICKEN OVERNIGHT IN RESPONSE TO THE TN VALLEY UPPER LOW/SHORTWAVE THAT WILL BE OPENING UP AND SLIDING INTO THE AREA. THE INCREASING CLOUDS...COMBINED WITH RISING DWPTS...WILL RESULT IN A MILD NIGHT WITH LOWS IN THE 60S...TO NR 70F ACROSS THE LOWER SUSQ VALLEY. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE UPPER LOW IS EXPECTED TO WEAKEN/OPEN UP AS IT SWINGS INTO THE REGION MONDAY. DIMINISHING LG SCALE FORCING OCCURRING DURING AM CONVECTIVE MINIMUM WILL LIKELY RESULT IN A DWINDLING AREA OF SHOWERS MOVING INTO SOUTHERN PA LATE MONDAY MORNING. HOWEVER...REMNANT SOUTHERLY LL JET AND ASSOC PLUME OF ANOMALOUS PWATS WILL LIE OVR THE AREA. MODEST HEATING OF THIS AIR MASS SHOULD PRODUCE NUMEROUS PM SHRA/TSRA. CONTINUE TO LEAN TOWARD SREF AND GEFS POPS...WHICH SUPPORT CATEGORICAL POPS OVR MUCH OF CENTRAL PA. MDL BLENDED QPF OF A 1/4 TO 1/2 INCH ON AVERAGE SEEMS REASONABLE. HOWEVER...CONVECTION-ALLOWING MDLS IMPLY LOCALIZED AMTS IN EXCESS OF 2 INCHES. GIVEN THE WET GROUND AND 1HR FFG VALUES LESS THAN AN INCH OVR MUCH OF CENTRAL PA...WILL INTRODUCE MENTION OF LOCAL FLOODING IN THE HWO. BEST CHC OF LOCALLY EXCESSIVE RAINFALL SHOULD BE ACROSS THE WESTERN AND SOUTHERN COUNTIES...WHERE MDL INSTABILITY THE GREATEST. WEAK FLOW ALOFT AND PRACTICALLY NON-EXISTENT DCAPE DUE TO LACK OF MID LVL DRY AIR SIGNALS A LOW CHC OF SVR WEATHER. MCLDY SKIES AND NUMEROUS PM SHRA/TSRA SHOULD HOLD TEMPERATURES TO BTWN 75-80F OVR MOST OF CENTRAL PA. HOWEVER...DWPTS PROGGED TO CREEP INTO THE UNCOMFORTABLE RANGE BTWN 65-70F. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE HEART OF A VERY WARM AND MUGGY AIRMASS WILL BE OVER THE STATE MONDAY NIGHT AND TUESDAY WITH MAINLY RAIN-FREE CONDITIONS BETWEEN 04-20Z TUESDAY. LATER TUESDAY AFTERNOON ISOLATED TO SCATTERED CONVECTION WILL FORM INVOF A LEE TROUGH...AND IN ADVANCE OF A SFC COLD FRONT APPROACHING FROM THE OHIO VALLEY. MUCH OF THE ENERGY PUSHING THIS FRONT EASTWARD APPEARS THAT IT/LL BE SHEARING OFF TO THE ENE ACROSS SRN ONTARIO AND QUEBEC. STILL A CLOSE CALL ENOUGH CALL FOR ADEQUATE DEEP-LAYER SHEAR TO BRING SCATTERED SHOWERS...AND ISOLATED STRONG TO POSSIBLY SVR TSRA /MAINLY ACROSS THE WEST/ LATE IN THE DAY TUESDAY AND TUESDAY NIGHT. LOW TEMPS EARLY TUESDAY WILL BE IN THE L-M 60S ACROSS THE MTNS...AND UPPER 60S TO AROUND 70F ACROSS THE CENTRAL AND SE ZONES. HIGHS TUESDAY AFTERNOON WILL RANGE THROUGH THE 80S. UPPER FLOW BECOMES FAIRLY ZONAL FOR THE MID TO LATE WEEK PERIOD AND A WEAKENING CFRONTAL BOUNDARY SHOULD SAG JUST TO THE SOUTH OF THE MASON DIXON LINE...WITH WEAK SFC RIDGING OVER THE STATE THURSDAY AND FRIDAY. ANY ORGANIZED CONVECTIVE CLUSTERS MOVING QUICKLY EAST FROM THE OHIO VALLEY IN FAST MID-UPPER LEVEL WESTERLY FLOW WILL BE VERY DIFFICULT TO TIME AND NOT WORTH ASSIGNING ANY MORE THAN 30-40 PERCENT POPS AT THIS POINT. TEMPS AND SFC DEWPOINTS WILL TREND DOWN TO NEAR...OR JUST SLIGHTLY BELOW NORMAL FOR THE SECOND HALF OF THE WEEK. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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EXPECT SHOWER ACTIVITY TO INCREASE IN COVERAGE AND SPREAD FROM SOUTH TO NORTH THROUGH THE AFTERNOON...AS AN UPPER LEVEL LOW CURRENTLY OVER WV/KY AND SFC WARM FRONT LIFTS NEWD ALONG THE CENTRAL APPALACHIANS. LOW VFR TO MVFR CIGS ARE FCST ACROSS MUCH OF THE AIRSPACE THRU THE PERIOD. SHOWERS WILL TEND TO BE SLOW-MOVG AND COULD PRODUCE HEAVY DOWNPOURS AND LCL IFR VISBYS. THE UPPER LOW WILL WEAKEN OVER CENTRAL PA INTO TNGT BUT STILL MAINTAIN SCT SHOWER RISK...THEREFORE SIMPLY WENT WITH VCSH AFT 00Z. CIGS/VSBYS SHOULD TREND GRADUALLY LOWER OVERNIGHT GIVEN DIURNAL COOLING...HIGH LOW LEVEL MSTR/NARROW T-TD SPEADS AND LGT WINDS...WITH AT LEAST MARGINAL RESTRICTIONS LKLY AT SEVERAL SITES INTO EARLY TUESDAY. LOWER CONDITIONS TUESDAY MORNING SHOULD IMPROVE BY AFTN. A COLD FRONT WILL APPROACH THE AIRSPACE FROM THE LWR LKS/OH VLY BY LATE IN THE DAY AND SHIFT SLOWLY SEWD INTO THE AIRSPACE TUE NGT/WED BEFORE STALLING OUT NEAR PA/MD BORDER THURS INTO FRIDAY. OUTLOOK... TUE-FRI...VFR/MVFR WITH PERIODS OF SHRA/AFTN TSTMS.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL

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