Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 070715 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 315 AM EDT TUE JUL 7 2015 .SYNOPSIS...
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A WARM FRONT FROM SOUTHERN PENNSYLVANIA THROUGH SOUTHERN NEW JERSEY WILL LIFT NORTHEAST OF OUR AREA TODAY. A COLD FRONT IS EXPECTED TO SLIDE SOUTHEAST INTO PENNSYLVANIA AND NEW JERSEY WEDNESDAY. IT WILL AWAIT THE PASSAGE OF TWO LOW PRESSURE SYSTEMS MOVING EAST ALONG THE FRONT WEDNESDAY NIGHT AND THURSDAY, THEN SINK SOUTH OF THE DELMARVA BY FRIDAY MORNING. WEAK HIGH PRESSURE FOLLOWS.
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&& .NEAR TERM /THROUGH TODAY/...
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EARLY TODAY...STRATUS AND A COUPLE OF DYING ISOLATED LEFTOVER SHOWERS FROM THIS PAST EVENINGS REMNANT HEAVY SHOWERS/TSTMS ON THE DELMARVA/E PA. PWAT RIGHT NOW STILL NEAR 1.9 INCHES BUT SLOWLY LOWERS FROM SW TO NE DURING THE DAY, DOWN TO NEAR 1.6 INCHES LATE AFTN. DENSE FOG RELEGATED TO THE RIDGES. UNSTABLE THIS AFTN IN THE WARM SECTOR AND MODELS CONTINUE DEVELOPING CLUSTERS OF HEAVY SHOWERS AND ISOLATED GULLY WASHING THUNDERSTORMS. BULK SHEAR IS MINIMAL TODAY SO ANY TSTORM GUSTS SHOULD NOT EXCEED 40 KT. BLENDED 00Z/7 GFS/NAM POPS WERE USED WITH SOME SREF/HRRR DIURNAL DRIER MORNING MODIFICATION OF THE POPS. IN ESSENCE THE SHOWERS TODAY TODAY MAINLY ALONG AND NW OF I-95, ESP E PA AND NORTHERN NJ (N OF I-78). OTHERWISE...THE STRATUS BURNS OFF RAPIDLY FROM SW TO NE DURING MID MORNING WITH A BKN DECK NEAR 5000 FT EARLY THIS AFTN AND THAT TOO DRYING OUT FROM SW TO NE DURING MID-LATE AFTN. HEAT FOLLOWS THIS AFTN WITH 90-92F EXPECTED TO BE WIDESPREAD ON A GUSTY SW WIND TO 20 MPH. THE HEAT INDEX WITH DEWPOINTS DIPPING BACK TO THE UPPER 60S SHOULD BE IN THE 95-99 CATEGORY FOR A FEW HOURS BUT NO HEAT ADVISORY. BLENDED THE 00Z/7 GFS/NAM MOS GUIDANCE AND MODIFIED IT UP A DEGREE FOR THE 16-17C 850 TEMPS. THE PRIMARY HAZARD TODAY WILL LIKELY BE POOR DRAINAGE ROAD FLASH FLOOD OPPORTUNITIES WHERE CONVECTION TRAINS FOR AN HOUR OR SO. HOURLY FFG IN MORRIS COUNTY IS OUR MOST VULNERABLE WITH 1 INCH IN AN HOUR. SUSPECT WE`LL SEE SOME CONVECTIVE NARROW SWATH FFW`S THIS AFTN ALONG AND N OF I-78. IF HEAVY SHOWERS HAVENT DEVELOPED BY 4PM, ITS UNLIKELY THEREAFTER IN OUR AREA. DRYING POPS TO NO MENTION AT 6 PM.
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&& .SHORT TERM /TONIGHT/...
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RAINFREE THIS EVENING AND QUITE WARM! THEN A BAND OF CONVECTION AHEAD OF THE EWD MOVING COLD FRONT MAY ARRIVE AND CROSS NE PA AND NW NJ NEAR AND AFTER MIDNIGHT WITH ISOLATED EMBEDDED THUNDER. PWAT IN THE EARLY EVENING B RIEFLY DRIES TO 1.4 INCHES BY WITH THE CONVECTIVE BAND RISES TO 1.85 INCHES BY WEDNESDAY MORNING. OTHERWISE...I CALL IT SUMMERTIME FAIR-A TYPICAL WARM SUMMER NIGHT! USED THE WARMER OF THE AVBL MOS GUIDANCE FOR TONIGHT. LIGHT SW WIND.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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THE MID LEVEL FLOW IS EXPECTED TO REMAIN SOMEWHAT ZONAL EAST OF THE ROCKIES FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS LOW PRESSURE MEANDERS OFF THE CALIFORNIA COAST, MOVES INLAND AND FILLS. THE MODEL GUIDANCE IS TRENDING TOWARD GREATER AMPLIFICATION OF THE MID LEVEL PATTERN OVER THE CENTRAL AND EASTERN STATES LATE IN THE WEEK WITH RIDGING DEVELOPING OVER THE GREAT LAKES. EVENTUALLY, A LONG WAVE RIDGE IS ANTICIPATED TO RETURN OVER THE ROCKY MOUNTAIN STATES DURING THE WEEKEND WITH A TROUGH SETTLING OVER THE EAST. IT CONTINUES TO APPEAR AS THOUGH A FRONTAL BOUNDARY WILL DROP INTO OUR REGION ON WEDNESDAY AND IT SHOULD REMAIN ACROSS OUR FORECAST AREA THROUGH THURSDAY NIGHT. THE NEARLY ZONAL FLOW WILL MAKE IT DIFFICULT TO TIME ANY MID LEVEL IMPULSES AND ASSOCIATED WEAK SURFACE WAVES. REGARDLESS, A CHANCE OF SHOWERS AND THUNDERSTORMS WILL EXIST THROUGH THAT PERIOD OF TIME. THE GUIDANCE IS SUGGESTING THAT A MID LEVEL SHORT WAVE TROUGH AND WEAK SURFACE LOW MAY PASS ACROSS OUR FORECAST AREA ON THURSDAY NIGHT PULLING THE SURFACE BOUNDARY TO THE SOUTH OF MARYLAND AND DELAWARE. PRECIPITABLE WATER VALUES ARE FORECAST TO RISE NEAR OR ABOVE 2 INCHES DURING THE MID WEEK PERIOD IN MUCH OF OUR REGION. ANY THUNDERSTORMS COULD BRING HEAVY DOWNPOURS ALONG WITH LOCALIZED FLOODING OF ROADWAYS AND AREAS OF POOR DRAINAGE. ALSO, WE WILL KEEP AN EYE ON THE FLASH FLOODING POTENTIAL ESPECIALLY IF CERTAIN AREAS ARE AFFECTED BY HEAVY RAINFALL ON MORE THAN ONE DAY. THE AMPLIFYING MID LEVEL FLOW SHOULD ALLOW HIGH PRESSURE TO WORK ITS WAY TOWARD OUR REGION FROM THE NORTHWEST AND NORTH FOR THE COMING WEEKEND. AS A RESULT, WE WILL NOT INDICATE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THAT PERIOD OF TIME. WE WILL FORECAST A RETURNING CHANCE OF SHOWERS AND THUNDERSTORMS FOR EARLY NEXT WEEK WITH THE SURFACE BOUNDARY EXPECTED TO RETURN NORTHWARD AS WARM FRONT. DAYTIME TEMPERATURES ARE ANTICIPATED TO BE WITHIN A FEW DEGREES OF NORMAL FOR THE PERIOD FROM TUESDAY NIGHT THROUGH MONDAY. NIGHTTIME TEMPERATURES ARE FORECAST TO BE ABOVE NORMAL.
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&& .AVIATION /07Z TUESDAY THROUGH SATURDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. AMD NOT SKED AT KACY DUE TO LACK OF TIMELY AUTOMATED TRANSMISSION OF METAR INFORMATION WHICH WITH IFR CONDITIONS. THROUGH ABOUT 14Z...WIDESPREAD CIGS AOB 1200 FEET WITH AREAS IFR STRATUS, ESPECIALLY VCNTY KABE/KTTN. 3-5 MILE FOG SHOULD DEVELOP BY 10Z BUT IT MAY NOT DROP BELOW 2 OR 3 MILES EXCEPT ON THE RIDGES OF THE POCONOS AND KITTATINYS IN NE PA AND NW NJ WHERE LIFR AND RIDGES WILL BE OBSCURED. SOUTHEAST WIND 5-10 KT BECOMES SOUTH SOUTHWEST BY 12Z. ISOLATED SHOWERS ON THE WANE AT 08Z. AFTER 14Z...AS THE WIND SHIFTS MORE SOUTHWESTERLY, CONDITIONS GRADUALLY IMPROVE TO VFR SCT-BKN AOA 3500 FEET BETWEEN 13Z AND 15Z. CIGS RISE FURTHER TO AOA 5000 FT EARLY THIS AFTERNOON THEN CLEAR FROM SW TO NE LATER IN THE DAY AS THE PWAT DROPS. SCATTERED IFR SHOWERS AND ISOLATED TSTMS IN THE 16Z-21Z TIME FRAME, MAINLY ALONG AND NW OF I-95. THESE STORMS MAY PRODUCE A GUST TO 35 KT. SOUTHWEST WIND GUSTS 15-20 KT AT ALL SITES DURING THE AFTN. TONIGHT...VFR CLEAR THIS EVENING THEN A DECK OF BKN CIGS AOA 5000 FT ARRIVES N OF I-78 (NEAR KABE AND KRDG) AFTER 04Z/8 ASSOCIATED WITH A DECAYING BAND OF CONVECTION AHEAD OF THE EWD MOVING COLD FRONT. OUTLOOK... WEDNESDAY MORNING...CONDITIONS POSSIBLY LOWERING TO MVFR OR IFR IN LOW CLOUDS, HAZE AND FOG ESPECIALLY DURING THE LATE NIGHT AND EARLY MORNING HOURS. WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...A CHANCE OF SHOWERS AND THUNDERSTORMS WHICH MAY CAUSE CONDITIONS TO LOWER TO MVFR OR IFR AT TIMES. FRIDAY THROUGH SATURDAY...MAINLY VFR.
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&& .MARINE...
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SUB-SCA CONDITIONS EXPECTED THROUGH THIS EVENING. ATLC SEAS MAY INCREASE TO THE HAZARDOUS 5 FT THRESHOLD LATE TONIGHT BUT NO SCA ATTM SINCE DURING WARM AIR ADVECTION, GUIDANCE TENDS TO HAVE A HIGH BIAS ON THE SEAS. WINDS WILL BECOME SW TODAY AND INCREASE TO 15 TO 20 KT LATE TODAY AND TONIGHT. OUTLOOK... WEDNESDAY THROUGH SATURDAY...NO MARINE HEADLINES ARE ANTICIPATED.
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&& .RIP CURRENTS...
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FORECASTING A LOW RISK TODAY USING A 3 FT 5 SECOND SOUTHERLY SWELL THIS AFTERNOON OR THIS MORNINGS 2 FT 9 SECOND. COMBINE THAT WITH A SOUTHERLY SFC WIND OF 12-13 KT THIS AFTERNOON AND WE GET A LOW RISK ALONG OUR WATERS. WE CANNOT OVEREMPHASIZE...LOW RISK DOES NOT MEAN NO RISK. TRANSITORY AND RECURRENT RIP CURRENTS OCCUR EVERY DAY. PLAY IT SMART AND SWIM SAFELY IN THE PRESENCE OF A LIFEGUARD WHO KNOWS WHAT THEY`RE DOING IF A RESCUE IS NEEDED. THEY ARE THERE INSTANTLY TO SAVE INSTEAD OF RECOVER.
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&& .EQUIPMENT... KACY DATA MAY NOT BE TRANSMITTING TO YOU THOUGH WE SEE IT INTERNALLY IN THE OFFICE. NO NOTAM. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG/IOVINO NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...IOVINO AVIATION...DRAG/IOVINO MARINE...IOVINO RIP CURRENTS... EQUIPMENT...

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