Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 212245 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 645 PM EDT THU AUG 21 2014 .SYNOPSIS... WEAK LOW PRESSURE WILL CROSS THE REGION TONIGHT THROUGH FRIDAY NIGHT AND THEN MOVE OFF THE COAST SATURDAY. HIGH PRESSURE WILL BUILD ACROSS THE AREA THIS WEEKEND AND REMAIN IN CONTROL OF THE WEATHER INTO NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA NEXT WEDNESDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... STABLE AIR WAS CONTINUING TO ADVECT OFF THE OCEAN EARLY THIS EVENING. DEW POINT READINGS WERE DROPPING INTO THE UPPER 50S AND LOWER 60S IN NEW JERSEY. MEANWHILE, CONDITIONS REMAINED UNSTABLE ON THE WESTERN SIDE OF OUR FORECAST AREA. CONDITIONS ARE FORECAST TO BECOME INCREASINGLY STABLE DURING THE EVENING WITH THE GRADUAL LOSS OF DAYTIME HEATING AND THE CONTINUED ONSHORE FLOW. WE HAVE ADJUSTED THE FORECAST TO REMOVE THE THUNDERSTORMS FROM ALL BUT TWO AREAS. WE WILL KEEP THE MENTION OF THUNDERSTORMS WITH HEAVY RAINFALL ACROSS OUR FAR NORTHERN COUNTIES FOR THIS EVENING TO ACCOUNT FOR THE CONVECTION MOVING ACROSS NORTHEASTERN PENNSYLVANIA AND INTO NORTHERN NEW JERSEY. THERE MAY BE SOME STRONG WIND GUSTS AND HAIL THERE, AS WELL. ALSO, WE WILL MAINTAIN THE EVENING THUNDERSTORM FORECAST WITH THE POTENTIAL FOR HEAVY RAINFALL IN NORTHEASTERN MARYLAND AND CENTRAL AND SOUTHERN DELAWARE AS SOME OF THE CONVECTION IN THE LOWER SUSQUEHANNA RIVER VALLEY MAY SLIDE SOUTHEASTWARD INTO THAT AREA. A MID LEVEL SHORT WAVE THAT WAS LOCATED OVER THE EASTERN GREAT LAKES REGION EARLY THIS EVENING SHOULD CONTINUE TO PROGRESS SOUTHEASTWARD AND IT IS ANTICIPATED TO PASS OVERHEAD LATE TONIGHT. AS A RESULT, WE WILL MAINTAIN SCATTERED SHOWERS THROUGHOUT OUR FORECAST AREA FOR TONIGHT. TEMPERATURES ARE EXPECTED TO DROP INTO THE 60S OVERNIGHT WITH A LIGHT SOUTH TO EAST WIND. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... 1000J OF MLCAPE AND SLIGHTLY STRONGER 0-6KM BULK SHEAR CUES INTEREST IN CONVECTION FRI AFTN. SREF HAS DECENT PROBS FOR SHOWERS...ESPECIALLY E PA...S NJ AND THE DELMARVA. FOR NOW HAVE PLAYED THE SHOWER AND TSTM RISK CONSERVATIVELY AND MAINTAINED THE 330 AM THURSDAY FCST POPS FOR FRIDAY...ABOUT 10 PCT BELOW THE 12Z/21 GFS/NAM MOS BLEND. IT WILL BE SLIGHTLY COOLER AS THE FLOW TURNS MORE EASTERLY AS THE SFC LOW CONSOLIDATES TO THE S OF THE DELMARVA. FCST BASIS: TEMPS/DEWS/WINDS ARE A 50 50 BLEND OF THE 12Z/21 GFS/NAM MOS. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... THE AREA WILL CONTINUE TO BE UNDER THE INFLUENCE OF THE WEAK UPPER LOW AND SFC LOW THU NIGHT AND INTO FRIDAY. SCT SHOWERS AND A FEW TSTMS WILL BE ACROSS MOST AREAS THU EVENING AND THEN DIMINISH OVERNIGHT...A COUPLE LEFTOVER SHOWERS WILL DEVELOP SAT MOSTLY ACROSS THE DELMARVA...SE PA AND SRN NJ. CHC FOR SHOWERS ARE ONLY IN THE CHC RANGE HOWEVER. A FEW DOWNPOURS ARE STILL POSSIBLE THU NIGHT WITH THE HIGHER PWATS STILL ACROSS THE SRN AREAS. LOWS THU NIGHT WILL MOSTLY BE IN THE LOW 60S ACROSS THE NORTH AND MID/UPPER 60S ELSEWHERE. HIGHS SAT IN THE UPPER 70S/LOW 80S SOUTH AND LOW TO MID 70S NORTH. DRIER AIR WILL CONTINUE TO PUSH IN FROM NORTH TO SOUTH SAT. AN UPPER RIDGE BUILDS UP TO THE WEST OF THE AREA THIS WEEKEND AND THEN ROTATES ACROSS THE AREA EARLY NEXT WEEK. SFC HIGH PRESSURE WILL MOVE SLOWLY IN TANDEM WITH THE UPPER HIGH. THIS WILL PRODUCE A PERIOD OF DRY WEATHER FOR OUR REGION. POPS FOR SAT NIGHT THRU NEXT WEN NIGHT ARE SUB-15PCT RANGE FOR THE ENTIRE AREA. TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL SUN/MON...NEAR NORMAL TUE...AND THEN A BIT ABOVE NORMAL WED/THU. HUMIDITY LEVELS WILL BE COMFORTABLE THROUGH MUCH OF THE PERIOD...BUT WILL TREND UP TOWARD THE MIDDLE OF NEXT WEEK. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. SCATTERED SHOWERS ARE ANTICIPATED FOR TONIGHT. ISOLATED THUNDERSTORMS ARE EXPECTED FOR THIS EVENING TO THE NORTH OF KABE AND KTTN AND TO THE WEST AND SOUTHWEST OF KPHL AND KILG. CONDITIONS SHOULD BE GENERALLY VFR THROUGH 0400Z EXCEPT THEY MAY LOWER TO MVFR IN RAIN SHOWERS. MVFR CONDITIONS ARE EXPECTED TO PREVAIL FROM LATE TONIGHT INTO FRIDAY MORNING. SOME SPOTS COULD FALL TO IFR DEPENDING UPON THE EXTENT OF ANY STRATUS AND FOG DEVELOPMENT ALONG WITH ADDITIONAL SHOWER ACTIVITY. MAINLY VFR CONDITIONS ARE EXPECTED TO RETURN FOR FRIDAY AFTERNOON AND THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AT THAT TIME. THE WIND SHOULD BACK FROM THE SOUTH AND SOUTHEAST TO THE EAST DURING THE TAF PERIOD. SPEEDS ARE EXPECTED TO BE MAINLY LESS THAN 10 KNOTS OUTLOOK... FRI NIGHT THRU SAT...MOSTLY VFR BUT SCT SHOWERS MAY BRING LOWER CONDITIONS. SAT NIGHT THRU TUESDAY...VFR EXPECTED. && .MARINE... SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED THROUGH FRIDAY WITH SEAS 3 FEET OR LESS AND SOUTH TO SOUTHEAST WINDS 5 TO 10 KNOTS BECOMING EASTERLY FRIDAY. WE`VE NOT SEEN ANY NEW MAREPS THIS WEEK FROM MARINERS IN OUR EASY USE (INTERNET AND/OR SMART PHONE) LINK WWW.WEATHER.GOV/PHI/MAROBSFORM THIS HAS BEEN DERIVED FOR THE MARINER TO EASILY POST INFO INSTANTLY TO THE NWS FOR USE IN OUR MARINE PRODUCTS. OUTLOOK... THU NIGHT THRU FRI NIGHT...SUB SCA CONDITIONS WITH SCT SHOWERS. SAT AND SAT NIGHT...LOW END SCA CONDITIONS EXPECTED ON THE OCEAN. FAIR WEATHER. SUN THRU TUE...SUB-SCA CONDITIONS WITH FAIR WEATHER. && .CLIMATE... WE RCD INQUIRY ON HOW THE CLIMATE PROGRAM SELECTS FOR OUR 530 PM CLI. OUR PROGRAM SEARCHES MAX/MIN TEMP DATA FOR THE DAY ENDING 5PM SHARP. THAT DATA IS INGESTED INTO THE 530 PM POSTED CLI. IF A MAX TEMP OCCURS THEREAFTER...IT IS REFLECTED IN THE END OF DAY SUMMARY POSTS AROUND 230 AM EDT THE NEXT DAY AND ALSO YOU CAN CHECK THE 8 PM RTPPHI WHICH POSTS AROUND 815 PM EDT. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...O`HARA NEAR TERM...IOVINO SHORT TERM...DRAG LONG TERM...O`HARA AVIATION...IOVINO/O`HARA MARINE...DRAG/O`HARA CLIMATE...DRAG

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