Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 131434 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1034 AM EDT SUN JUL 13 2014 .SYNOPSIS...
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A STRONG UPPER LEVEL TROUGH WILL DROP INTO THE UPPER GREAT LAKES BY MONDAY. A PAIR OF SURFACE COLD FRONTS ASSOCIATED WITH THIS TROUGH WILL PUSH SOUTHEAST AND BRING SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS TO THE REGION OVER THE NEXT 36 HOURS. COOLER AND DRIER AIR WILL MOVE INTO THE COMMONWEALTH FOR THE MID TO LATE WEEK PERIOD.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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THE NOSE OF STRONGER 35 TO 40 KTS SWRLY LLVL WINDS AND 2 INCH PWAT AIR /ASSOCIATED WITH A WARM FRONT/ WILL SLIDE ACROSS NWRN PENN LATE THIS MORNING. THIS AXIS OF HIGHER WIND AND MOISTURE WILL SHIFT A BIT FURTHER SOUTH AND EAST THIS AFTERNOON. POCKETS OF MDTLY HIGH SFC BASED INSTABILITY WILL DEVELOP AND COMBINE WITH THE ANOMALOUS 850-700 MB WINDS TO BRING THE THREAT OF SCATTERED STRONG TO SVR TSRA THIS AFTERNOON AND EARLY THIS EVENING. IF THE CLOUD DEBRIS AND COOLING EFFECTS THEREOF ARE NOT TOO SIGNIFICANT TODAY...THE CAPES THIS AFTN COULD TOP 1500 JOULES. SPC HAS ALMOST THE ENTIRE AREA IN THE SLIGHT RISK AREA TODAY INTO TONIGHT. NAM 0-1 KM EHI VALUES PEAK BETWEEN 2-3 M2/S2 ACROSS THE NCENT MTNS AROUND 18-20Z...THEN SHIFT TO THE MID SUSQ VALLEY AND ADJACENT AREAS OF ECENT PENN 20-22Z. THESE WILL BE THE AREAS OF GREATEST CONCERN FOR A FEW SUPERCELLS...AND PERHAPS 1 OR 2 BRIEF TORNADOES. OTHERWISE...MINI BOW ECHOES WITH LOCALIZED DAMAGING MICROBURSTS WILL BE THE MOST PROBABLE TYPE OF SEVERE WEATHER THIS AFTERNOON AND EARLY THIS EVENING. MORE SCATTERED...MULTI-CELL /OR PERHAPS A BRIEF SUPERCELL/ TSRA IS ANTICIPATED ACROSS THE SE HALF OF THE CWA. RAINFALL COULD BE HEAVY ACROSS THE NRN TIER...BUT THE FAST 35-45KT ENE MOVEMENT OF THE CELLS WILL MAKE IT DIFFICULT FOR ANY ONE OR TWO BURSTS OF RAIN TO CAUSE FLOODING. HOWEVER... MULTIPLE/REPEATED STORMS ARE LIKELY IN THE NORTHWESTERN HALF OF THE AREA THROUGH THE NEAR TERM...AND THIS MAY CAUSE LOCAL POOR DRAINAGE AND SMALL STREAM FLOODING. FFG/S CONTINUE TO BE RATHER HIGH AND SERIOUS PROBLEMS/FLASH FLOODING IS NOT ANTICIPATED AT THIS TIME. LOCALLY HEAVY RAIN NEAR LEBANON AND LANCASTER HAS LOWERED FLOOD GUIDANCE THERE...BUT THE STORMS WILL BE MORE- SCATTERED AROUND THAT PARTICULAR AREA TODAY. THE THICKNESS/PERSISTENCE OF THE CLOUD COVER TODAY WILL BE THE TRICK TO WHERE TEMPS GO. DUE TO THE CLOUDS AND ANTICIPATED CONVECTION/RAIN - WILL HANG WITH CONTINUITY AND ADD ABOUT 10F TO THE CURRENT TEMPS IN THE NW AND ABOUT 15F TO THE CURRENT TEMPS IN THE SE FOR MAXES TODAY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... CONVERGENCE WILL CONCENTRATE FROM JST-UNV-IPT THIS EVENING...AND ONLY SINK SLOWLY TO THE SOUTH. BUT THIS FIRST SHOT OF COOLER AIR FROM THE NORTHWEST IS NOT ENOUGH TO DISPLACE THE WARM AIR AND HIGH MOISTURE SO ADDITIONAL STORMS ARE EXPECTED OVERNIGHT. REDEVELOPMENT IS ALMOST SURELY IN THE CARDS FOR MONDAY AS CLOUDS THIN BRIEFLY AND JULY SUN STIRS UP THE BOUNDARY LAYER OVER MOST OF THE AREA. SLIGHT RISK OUTLOOK FROM SPC IS HELD TO JUST THE S/SE THIRD OF THE AREA MONDAY. HOWEVER...FEEL THAT STRONG STORMS ARE POSSIBLE A LITTLE FARTHER TO THE NORTH WITH LOW-LEVEL AMBIENT MOISTURE STILL HIGH AND OVERALL MOISTURE HIGH WITH PWATS BETWEEN 1.5 AND 2 INCHES. WILL HOLD THE CATG POPS TO THE SE...BUT GO LIKELY POPS OVER MUCH OF THE REST OF THE AREA ON MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... THE GFS AND NAM GUIDANCE IS MUCH QUICKER TO PUSH THE FRONT THROUGH...WITH THE ECMWF DEEPENING THE UPPER LEVEL TROUGH...THOUGH THE LATEST RUN HAS OPENED UP THE CLOSED LOW. THE EC DEVELOPS A COHERENT SFC LOW OVER THE MID MS VALLEY AND MOVES IT TO OUR W/N ON TUESDAY AS IT DEEPENS TO NEAR 1003MB. HIGH AMPLITUDE RIDGE/TROUGH PATTERN DEVELOPS ACROSS THE MUCH OF NORTH AMERICA BEGINNING LATE IN THE WEEKEND...AND CONTINUES THROUGH THE FIRST HALF OF NEXT WEEK. THE BRUNT OF THE GREATEST 850-700 MB TEMP ANOMALIES AND ASSOCIATED BELOW NORMAL 500 MB HEIGHTS WILL BE AIMED AT THE LOWER OHIO VALLEY AND MID MISS VALLEY TUESDAY AND WEDNESDAY...WITH OUR REGION RESIDING ON THE ACTIVE/EASTERN SIDE OF THIS SLOW MOVING FEATURE. AS ADDITIONAL ENERGY IS DRIVEN SSE INTO THE BACK SIDE OF THE HIGH AMPLITUDE MIDWEST TROUGH...PROLONGED HIGH PWAT AIR /AND LIFT BENEATH THE RIGHT ENTRANCE REGION OF AN UPPER JET/ MAY LINGER ACROSS THE SERN ZONES WITH SCATTERED...MAINLY AFTERNOON TSRA WEDNESDAY AFTERNOON. THE PATTERN OVER THE NRN CONUS AND SRN CANADA APPEARS TO DE- AMPLIFY LATER NEXT WEEK AS THE EASTERN U.S. TROUGH BEGINS TO SHEAR OUT TO THE NE. THE DRIEST PERIOD OF THE LONG TERM WILL BE THURSDAY AND FRIDAY...THOUGH SOME ISOLATED CONVECTION STILL CANT BE RULED OUT EITHER OF THOSE TWO DAYS. TEMPS START OUT AOA NORMAL PRECEDING THE CFROPA NEXT SUNDAY...AND PERHAPS MONDAY ACROSS THE SE ZONES...THEN COOL TO AT LEAST 4-6F BELOW NORMAL FOR DAYTIME HIGHS TUESDAY THROUGH THURSDAY. TEMPS WILL LIKELY REBOUND TO NEAR NORMAL LATE NEXT WEEK. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/...
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AN APPROACHING FRONT WILL BRING THE CHANCE OF TSRA IMPACTS TO THE MAINLY THE NORTHWEST MTNS OF PENN /THEN CENTRAL COUNTIES/ TODAY. NUMEROUS SHRA/TSRA MOVING INTO THE KBFD VCNTY ATTM AND WILL SPREAD SEWD THROUGHOUT THE MIDDAY AND AFTERNOON HOURS TODAY...BUT SITES WILL REMAIN MAINLY VFR THROUGH THE BULK OF THE TAF PERIOD. BRIEF REDUCTIONS IN VSBY AND CIGS ARE POSSIBLE AGAIN TOMORROW AFTERNOON IN THUNDERSTORMS. OUTLOOK... THIS AFTERNOON AND EVENING...BRIEF THUNDERSTORM IMPACTS POSSIBLE. SUN NIGHT-MON NIGHT...NUMEROUS SHOWERS/TSRA WITH MAINLY BRIEF PERIODS OF IFR TO MVFR. TUES-WED...THUNDERSTORM IMPACTS POSSIBLE...MAINLY IN THE AFTERNOON. THU...NO SIG WX EXPECTED.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...LAMBERT/DANGELO SHORT TERM...DANGELO/LAMBERT LONG TERM...CERU AVIATION...LAMBERT/GARTNER

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