Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 031321 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 921 AM EDT MON AUG 3 2015 .SYNOPSIS... A COLD FRONT FROM THE GREAT LAKES WILL SLOWLY APPROACH FROM THE NORTHWEST TODAY, EVENTUALLY TRACKING THROUGH OUR REGION INTO EARLY TUESDAY. THIS FRONT IS FORECAST TO STALL JUST SOUTH OF OUR AREA THROUGH THE MIDDLE TO END OF THE WEEK WITH WAVES OF LOW PRESSURE MOVING ALONG IT. THE FINAL WAVE OF LOW PRESSURE LOOKS TO PASS OFFSHORE SATURDAY WITH HIGH PRESSURE FROM EASTERN CANADA POSSIBLY BUILDING SOUTHWARD ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST ON TRACK THIS MORNING. A BEAUTIFUL EARLY AUGUST DAY SHAPING UP WITH A BIT OF A BREEZE AND GOOD MIXING TO GET THAT DRIER AIR DOWN TO THE SURFACE. OTHER THAN MAYBE THE DELMARVA, APPARENT TEMPERATURES SHOULDN`T BE ANY HIGHER THAN THE ACTUAL AIR TEMPERATURES. I ADJUSTED THE SKY COVER GRIDS AFTER GETTING A HANDFUL OF VISIBLE SAT SHOTS, BUT LEFT THE FORECASTED HIGH TEMPS AND WEATHER GRIDS (SUPPORTED BY HRRR) FOR TODAY AS IS. PREVIOUS DISCUSSION... MOSTLY A DRY DAY IS EXPECTED AS AIRMASS MODIFICATION CONTINUES. DEEPER MIXING TODAY WILL KEEP THE SURFACE DEWPOINTS IN CHECK, FOR THE MOST PART, SO NOT EXPECTING SWELTERING CONDITIONS WITH TEMPERATURES A FEW DEGREES WARMER THAN THE PAST COUPLE DAYS. STRENGTHENING SOUTHERLY WINDS, WITH GUSTS UPWARDS OF 25 MPH, WILL HELP TO USHER IN MORE MOISTURE BUT WITHOUT AN APPRECIABLE TRIGGER, EVEN AS MLCAPES CLIMB TOWARDS 1500J/KG THIS AFTERNOON, SHOULD KEEP US MOSTLY STORM FREE UNTIL LATER THIS EVENING. WEAKENING COLD FRONTAL PASSAGE SHOULD TRIGGER A LINE OF STORMS TO OUR WEST BY MID- AFTERNOON, SO IT BASICALLY BECOMES A RACE AGAINST THE BETTER SURFACE HEATING AND IF THE STORMS CAN SPEED UP. ANY STORMS THAT DO MOVE INTO OUR REGION WILL HAVE A DECENT AMOUNT OF SHEAR IN PLACE, ORIENTED PERPENDICULAR TO THE FRONTAL CONVERGENCE ZONE, WHICH WOULD ALLOW FOR BETTER ORGANIZATION AND POSSIBLE BOWING SEGMENTS...HAVE GUSTY WINDS ADDED INTO THE GRIDS FOR LATE THIS EVENING. IT IS POSSIBLE THAT PRE- FRONTAL/THERMAL TROUGH DEVELOPS WELL AHEAD OF THE COLD FRONT WHICH COULD BE OUR MAIN TRIGGER DURING THE MID-AFTERNOON HOURS SO WE COULD BE A TAD SLOW WITH OUR CHANCE POPS TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... COLD FRONT WILL CONTINUE TO SLIP THROUGH THE REGION BUT BEGIN TO SLOW ITS FORWARD PROGRESS AS THE FLOW ALOFT TURNS MORE PARALLEL WITH TIME...IT SHOULD STALL ACROSS OUR SOUTHERN ZONES LATE TONIGHT. NOT QUITE SURE HOW QUICKLY WE CAN DRY OUT WEST TO EAST BEHIND THE FRONT SINCE WE REALLY DO NOT SEE MUCH OF AN AIRMASS CHANGE. A MID-LEVEL IMPULSE, JUST BEHIND THE SURFACE FRONT, LOOKS TO PUSH THROUGH WHICH MAY EITHER CONTINUE THE ON-GOING CONVECTION IN THE EASTERN PORTIONS OF OUR CWA OR GENERATE A FEW TRAILING SHOWERS HEADING INTO DELMARVA AFTER MIDNIGHT TONIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AN ACTIVE AND UNSETTLED PATTERN IS ANTICIPATED THROUGH THE LONG TERM PERIOD AS A FRONTAL BOUNDARY WILL BE STALLING JUST SOUTH OF OUR FORECAST AREA WITH A FEW WAVES OF LOW PRESSURE EXPECTED TO DEVELOP AND MOVE ALONG IT THROUGH THE END OF THE WEEK AND PERHAPS INTO THE EARLY PART OF THE UPCOMING WEEKEND. FOR TUESDAY, A COLD FRONT IS FORECAST TO BE TRACKING THROUGH OUR AREA EARLY IN THE DAY, EVENTUALLY STALLING OUT TO OUR SOUTH AND EAST INTO TUESDAY NIGHT. THE PRESENCE OF THE STALLING FRONT NEAR/ACROSS OUR AREA WILL KEEP SOME SLIGHT CHANCE TO LOW CHANCE POPS FOR SHWRS/TSTORMS IN THE FORECAST FOR TUESDAY, ESPECIALLY FOR EASTERN AND SOUTHERN LOCATIONS, INCLUDING EASTERN/SOUTHERN NJ AND INTO THE DELMARVA. MEANWHILE FOR THE I-95 CORRIDOR AND AREAS NORTH AND WEST, THE CONVECTIVE POTENTIAL LOOKS TO BE MINIMAL WITH ENSUING CAA AND FALLING DEWPOINTS IN THE WAKE OF THE COLD FRONT PASSAGE. DESPITE THE STALLED FRONTAL BOUNDARY LINGERING JUST TO OUR SOUTH, WEDNESDAY LOOKS TO BE A PRECIP-FREE DAY AT THIS TIME, AS A WAVE OF LOW PRESSURE DOES NOT LOOK TO DEVELOP ALONG THE BOUNDARY UNTIL MORE DURING THE DAY THURSDAY. IN ADDITION, AS NOTED BY THE PREVIOUS SHIFT, CONVECTIVE TEMPS ARE NOT FORECAST TO BE REACHED DURING THE DAYTIME WEDNESDAY, AND DRIER LOW-LEVEL AIR WILL STILL BE IN PLACE WITH DEWPOINTS ACROSS MUCH OF THE REGION IN THE 50S TO LOW 60S. MAXIMUM TEMPS LOOK TO BE RIGHT AROUND EARLY AUGUST AVERAGES WITH HIGHS MAINLY IN THE MID TO UPPER 80S ACROSS THE AREA. FOR THE REMAINDER OF THE LONG TERM FROM THURSDAY THROUGH SATURDAY, WITH THE STALLED FRONTAL BOUNDARY JUST OFF TO OUR SOUTH AND A FEW WAVES OF LOW PRESSURE POTENTIALLY TRACKING ALONG IT, THERE WILL BE HIGHER CHANCES FOR SCATTERED SHWR/TSTORM ACTIVITY, ALONG WITH THE POTENTIAL FOR HEAVY RAIN. WE CARRY HIGH CHANCE POPS OVERALL THROUGH MOST OF THIS PERIOD; ALTHOUGH, THERE ARE STILL NOTEABLE MODEL DIFFERENCES WITH REGARDS TO THE TIMING AND TRACK OF THE DEVELOPING WAVES OF LOW PRESSURE. SO WHILE THIS TWO TO THREE DAY PERIOD LOOKS TO HAVE A HIGHER PROBABILITY FOR INCREASED SHWR/TSTORM ACTIVITY, THERE IS TOO MUCH UNCERTAINTY AT THIS EXTENDED RANGE TO NARROW DOWN THE TIMING AND/OR AREAL EXTENT OF CONVECTIVE ACTIVITY AND ASSOCIATED AREAS OF HEAVY RAIN. WE WILL CONTINUE TO HIGHLIGHT THIS POTENTIAL, THOUGH, IN OUR HAZARDOUS WEATHER OUTLOOK. SOME IMPROVEMENT MAY BE EXPECTED INTO THE UPCOMING WEEKEND, ESPECIALLY FROM LATE SATURDAY INTO SUNDAY, AS THE LAST WAVE OF LOW PRESSURE TRAVELS EAST AND OUT TO SEA, WITH AN AREA OF HIGH PRESSURE ACROSS EASTERN CANADA BUILDING SOUTHWARD TOWARD THE NORTHEAST TO NORTHERN MID ATLANTIC DURING SUNDAY. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...VFR. SOUTHERLY WINDS AROUND 8 TO 10 KNOTS BY LATER THIS MORNING WITH SOME GUSTS CLOSE TO 20 KNOTS THROUGH THE EARLY EVENING HOURS. STRATOCU AROUND 5KFT THIS AFTERNOON. MOST OF THE SHOWERY ACTIVITY SHOULD HOLD OFF UNTIL LATE EVENING...MOSTLY NW OF ABE. TONIGHT...VFR. SHOWERS AND THUNDERSTORMS POSSIBLE BUT SCATTERED COVERAGE DOES NOT ALLOW INCLUSION IN TAFS AT THIS TIME. WE WILL LOSE THE GUSTS AS WINDS REMAINS LIGHT OUT OF THE SOUTH. OUTLOOK... TUESDAY...MOSTLY VFR CONDITIONS. ISOLATED TO PERHAPS SCATTERED SHWRS/TSTORMS ARE POSSIBLE, ESPECIALLY EASTERN TERMINALS. WEDNESDAY...MAINLY VFR CONDITIONS. THURSDAY AND FRIDAY...MVFR CONDITIONS DURING SHWRS/TSTORMS, WITH SOME IFR CONDITIONS POSSIBLE. WHILE CONFIDENCE OF OCCURRENCE IS INCREASING, TIMING CONFIDENCE REMAINS LOW. && .MARINE... SCA CONDITIONS LOOK TO COMMENCE LATER THIS AFTERNOON WITH TIGHTENING PRESSURE GRADIENT AND STRENGTHENING SOUTHERLY FLOW RAISING SEAS TOWARDS 5 FEET. NUMEROUS GUSTS UPWARDS OF 25 KNOTS ARE EXPECTED TO OCCUR AHEAD OF AN APPROACHING COLD FRONT LATER TONIGHT. OUTLOOK... TUESDAY...A SMALL CRAFT ADVISORY WILL CONTINUE FOR THE COASTAL WATERS THROUGH TUESDAY MORNING. WHILE WIND GUSTS ARE EXPECTED TO HAVE FALLEN OFF BY EARLY TUESDAY, SEAS WILL LIKELY STILL REMAIN AT 5 FEET OR ABOVE THROUGH TUESDAY MORNING. IMPROVING CONDITIONS WITH SEAS SUBSIDING ARE EXPECTED INTO TUESDAY AFTERNOON. WEDNESDAY...SUB-ADVISORY CONDITIONS ARE EXPECTED. THURSDAY AND FRIDAY...MOSTLY SUB-SCA CONDITIONS; HOWEVER, A STALLED FRONT AND A WAVE OF LOW PRESSURE MOVING ALONG IT COULD ENHANCE SEAS AND/OR WINDS FOR THE COASTAL WATERS, MAKING SCA CONDITIONS POSSIBLE. && .RIP CURRENTS... THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS TODAY FOR THE NEW JERSEY SHORE AND THE DELAWARE BEACHES. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM EDT TUESDAY FOR ANZ450>455. && $$ SYNOPSIS...GIGI/KLINE NEAR TERM...HEAVENER/KRUZDLO SHORT TERM...HEAVENER LONG TERM...KLINE AVIATION...GIGI/HEAVENER/KLINE MARINE...HEAVENER/KLINE RIP CURRENTS...

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