Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 280428 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1228 AM EDT THU AUG 28 2014 .SYNOPSIS... A WEAK COLD FRONT WILL SLIDE ACROSS THE REGION TONIGHT, HELPING TO KEEP HURRICANE CRISTOBAL WELL EAST OF THE MID ATLANTIC COAST INTO THURSDAY. HIGH PRESSURE BUILDS IN THURSDAY AND FRIDAY, THEN SHIFTS OFFSHORE INTO SATURDAY. A WARM FRONT SHOULD LIFT NORTH ACROSS THE REGION SATURDAY, THEN A FRONTAL BOUNDARY MAY STALL TO OUR NORTH SUNDAY AND MONDAY. THE NEXT COLD FRONT IS SCHEDULED TO ARRIVE WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE COLD FRONT EXTENDED FROM AROUND PERTH AMBOY TO TRENTON TO NORRISTOWN TO COATESVILLE AROUND MIDNIGHT IT WILL CONTINUE TO DROP SOUTHWARD THROUGH THE REMAINDER OF OUR FORECAST AREA BEFORE DAYBREAK. AN ISOLATED SHOWER LINGERED NEAR HAZLETON IN PENNSYLVANIA. ANOTHER MORE SUBSTANTIAL SHOWER WITH ISOLATED LIGHTNING WAS LOCATED IN MORRIS COUNTY, NEW JERSEY AROUND DENVILLE AND BOONTON. THERE WAS ONE ADDITIONAL LIGHT SHOWER NEAR WARREN TOWNSHIP IN SOMERSET COUNTY. THE PRECIPITATION SHOULD CONTINUE TO WEAKEN AND EVENTUALLY DISSIPATE AS IT MOVES SOUTHEASTWARD. WE WILL REMOVE THE MENTION OF PRECIPITATION FROM THE FORECAST BASED ON ITS VERY LIMITED COVERAGE AND ON THE EXPECTATION THAT IT SHOULD EITHER DISSIPATE OR MOVE OUT OF OUR FORECAST AREA BY ABOUT 130 AM. A LIGHT NORTHWEST WIND WILL CONTINUE TO DEVELOP IN THE WAKE OF THE COLD FRONT AND TEMPERATURES SHOULD DROP INTO THE 60S AT MOST LOCATIONS. THE SKY IS EXPECTED TO CLEAR FROM NORTHWEST TO SOUTHEAST WITH PERHAPS SOME CLOUDS LINGERING OVER OUR SOUTHEASTERN COUNTIES AT DAYBREAK. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM FRIDAY/... THE COLD FRONT IS EXPECTED TO MOVING SOUTH OF THE DELMARVA DURING THE MORNING ON THURSDAY. HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES BEHIND THE FRONT. THE OFFICIAL NHC FORECAST CALLS FOR HURRICANE CRISTOBAL TO BE LOCATED ABOUT 500 MILES OFF THE MID- ATLANTIC COAST 12Z THURSDAY BEFORE ACCELERATING TO THE EAST- NORTHEAST, MOVING FARTHER OUT TO SEA DURING THE DAY. THE PRESSURE GRADIENT BETWEEN THE HIGH TO OUR NORTHWEST AND THE COLD FRONT TO OUR SOUTH/HURRICANE CRISTOBAL TO OUR EAST WILL PRODUCE A BREEZY NORTHWEST WIND 10-15 MPH ACROSS OUR AREA. THESE WINDS WILL USHER IN RELATIVELY COOL AND DRY AIR WITH THE SOURCE OF THIS POST-FRONTAL AIR MASS FROM CANADA. FORECAST MAX TEMPS IN THE LM80S FOR MOST OF THE REGION, EXCEPT MU70S IN THE MOUNTAINS. && .LONG TERM /FRIDAY THROUGH THURSDAY/... THE OVERALL SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH EXITING THE NORTHEAST THURSDAY NIGHT INTO FRIDAY, THEN A SHORT WAVE TROUGH TRACKING ACROSS THE NORTHERN PLAINS AND MIDWEST WILL BUILD A RIDGE ACROSS THE EAST FRIDAY AND INTO THE WEEKEND. THIS RIDGE MAY HOLD FOR AWHILE, HOWEVER ADDITIONAL SHORT WAVES WILL CARVE OUT ANOTHER UPPER-LEVEL TROUGH THAT EVENTUALLY SHIFTS EASTWARD ACROSS THE MIDWEST AND GREAT LAKES REGION. AN ASSOCIATED COLD FRONT SHOULD ARRIVE TOWARD THE END OF THIS TIME FRAME, ALTHOUGH AN INITIAL FRONT MAY STALL TO OUR NORTH BEFORE RETREATING NORTHWARD. WE USED A MODEL BLEND FOR THURSDAY NIGHT THROUGH SATURDAY, THEN WENT WITH THE 12Z WPC GUIDANCE. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR SURROUNDING OFFICES. FOR THURSDAY NIGHT AND FRIDAY...AN UPPER-LEVEL TROUGH WILL BE EXITING TO OUR EAST FOLLOWED BY SOME RIDGING. THIS WILL PUSH HIGH PRESSURE ACROSS THE NORTHEAST AND MID ATLANTIC REGIONS. THE CENTER OF THE SURFACE HIGH WILL PROBABLY BE LOCATED JUST TO OUR NORTH, THEREFORE A NORTHWEST TO NORTH SURFACE WIND SHOULD OCCUR. THIS WILL HELP ADVECT A DRIER AIR MASS INTO THE AREA ALONG WITH COOLER AIR THROUGH FRIDAY. HOWEVER, THE SURFACE HIGH SHOULD BE SHIFTING OFFSHORE FRIDAY NIGHT ALLOWING FOR A RETURN FLOW TO START BECOMING ESTABLISHED. A SYSTEM MOVING ACROSS THE NORTHERN PLAINS AND MIDWEST WILL ASSIST IN WAA DEVELOPING NORTHBOUND UP THE OHIO VALLEY. THIS SHOULD ALSO ORGANIZE A WARM FRONT TO OUR SOUTHWEST. FOR SATURDAY AND SUNDAY...THE BUILDING OF AN UPPER-LEVEL RIDGE IS FORECAST TO OCCUR DURING THIS TIME FRAME, HOWEVER SHORT WAVE ENERGY TRAVELING FROM THE MIDWEST TO THE GREAT LAKES REGION WILL TRY AND FLATTEN IT SOME. DUE TO THE RIDGE AND ALSO SURFACE HIGH PRESSURE SITUATED OFFSHORE, A SOUTHWESTERLY FLOW OF WARM/HOT AND INCREASINGLY MORE HUMID AIR WILL OVERSPREAD THE AREA. WHILE THERE MAY BE SOMEWHAT OF A MOISTURE SURGE AS A WARM FRONT LIFTS NORTH ACROSS THE AREA SATURDAY, THE OVERALL FORCING LOOKS WEAK WITH MUCH OF THE ENERGY FOCUSED CLOSER TO THE GREAT LAKES. THEREFORE, WE MAINTAINED A DRY FORECAST FOR SATURDAY. AN INITIAL DISTURBANCE MAY END UP WEAKENING AS IT TRAVERSES A FRONTAL BOUNDARY TO OUR NORTH AND WEST SUNDAY AS IT RUNS INTO THE NORTHWEST FLANK OF THE UPPER- LEVEL RIDGE. DESPITE THIS, THERE COULD BE SOME CONVECTION ON THE SOUTHEASTWARD FLANK OF THIS WEAKENING DISTURBANCE SUNDAY. IF A LEE SIDE TROUGH DEVELOPS, THIS COULD ALSO BE THE FOCUS FOR SOME CONVECTIVE DEVELOPMENT WITHIN THE LARGE WARM SECTOR. GIVEN THE HEAT AND HIGHER HUMIDITY IN PLACE, SOME THUNDERSTORMS COULD BE LOCALLY STRONG FROM OUR WESTERN ZONES AND ESPECIALLY WEST OF OUR CWA. THIS CARRIES LOWER CONFIDENCE THOUGH DUE TO SOME UNCERTAINTY ON CONVECTIVE INITIATION AND COVERAGE AND THE TIMING OF EMBEDDED FEATURES. FOR NOW, WE CARRIED CHC POPS OR LESS DURING SUNDAY. FOR MONDAY AND TUESDAY...AS AN UPPER-LEVEL TROUGH RELOADS ACROSS THE NORTHERN PLAINS AND MIDWEST MONDAY, A RIDGE IS STILL NEAR OUR AREA MAINTAINING A SOUTHWESTERLY FLOW. THERE APPEARS TO BE A STALLED BAROCLINIC ZONE THOUGH TO OUR NORTH, HOWEVER AS OF NOW THERE IS NO REAL STRONG SURFACE HIGH TO PUSH THIS SOUTHWARD, PLUS THE RIDGING FARTHER SOUTH MAY BE STRONG ENOUGH TO KEEP IT AT BAY. HOWEVER, THE MODEL GUIDANCE SUGGESTS THAT WITHIN A RATHER WARM AND MOIST AIR MASS A LEE SIDE TROUGH MAY BE PRESENT AND EVEN SHARPEN UP SOME. WITH ANY SUBTLE SHORT WAVES TRACKING AROUND THE NORTHWESTERN PERIPHERY OF THE LINGERING RIDGE, SOME CONVECTION COULD DEVELOP IN TANDEM WITH THE LEE SIDE TROUGH. AS A RESULT, WE WILL CARRY SLIGHT CHC TO LOWER CHC POPS ESPECIALLY INLAND. THERE ARE SOME TIMING DIFFERENCES IN THE MODEL GUIDANCE, THEREFORE WE FOLLOWED MORE CLOSELY TO THE 12Z WPC GUIDANCE. FOR WEDNESDAY...AN AMPLIFYING UPPER-LEVEL TROUGH FROM THE MIDWEST AND GREAT LAKES REGION SHOULD PUSH A COLD FRONT INTO OUR REGION. WHILE THERE ARE SOME TIMING DIFFERENCES IN THE MODEL GUIDANCE, WE DID STAY CLOSER TO WPC GUIDANCE. THIS BRINGS THE ACTUAL COLD FRONT INTO OUR AREA LATER IN THE DAY. AS HEIGHTS FALL, THE FRONT ARRIVES AND LARGE SCALE FORCING GENERALLY ARRIVES, SOME CONVECTION IS POSSIBLE. IF THIS OCCURS DURING PEAK HEATING WITH ENOUGH SHEAR, CONVECTION COULD BE MORE ORGANIZED. OVERALL, WE WENT RATHER CLOSE TO THE 12Z WPC GUIDANCE. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. OCCASIONALLY BROKEN CEILINGS AROUND OR ABOVE 4000 FEET SHOULD CLEAR FROM NORTHWEST TO SOUTHEAST DURING THE OVERNIGHT PERIOD. A MOSTLY CLEAR SKY IS ANTICIPATED FOR THURSDAY. A LIGHT NORTHWEST WIND WILL DEVELOP OVERNIGHT. WIND SPEEDS ARE FORECAST TO INCREASE INTO THE 8 TO 12 KNOT RANGE ON THURSDAY WITH GUSTS NEAR 20 KNOTS, ESPECIALLY IN THE AFTERNOON. OUTLOOK... THURSDAY NIGHT AND FRIDAY...VFR. LIGHT WINDS BECOMING NORTHEAST, AND THEN SOUTHERLY FRIDAY. SATURDAY AND SUNDAY...A CHANCE OF LOCAL FOG EACH EARLY MORNING, OTHERWISE MAINLY VFR. SOME INCREASE IN CLOUDS POSSIBLE SATURDAY AS A WARM FRONT LIFTS NORTHWARD. SOME SHOWERS AND THUNDERSTORMS ARE POSSIBLE SUNDAY, WITH A CHANCE FOR LOCALLY SUB-VFR CONDITIONS. SOUTH AND SOUTHEAST WINDS SATURDAY 5-10 KNOTS, BECOMING SOUTH- SOUTHWEST SUNDAY. MONDAY...VFR, WITH THE EXCEPTION OF POSSIBLE BRIEF TIMES OF MVFR ASSOCIATED WITH A SHOWER OR THUNDERSTORM. LOWER CONFIDENCE REGARDING PRECIPITATION COVERAGE. SOUTHWESTERLY WINDS GENERALLY NEAR 10 KNOTS. && .MARINE... AS OF MIDNIGHT...SEAS AT BUOY 44009 ARE STILL HOLDING AT 4 FEET. STILL BELIEVE THAT SWELLS FROM CRISTOBAL WILL AFFECT THE NJ AND DE COASTAL WATERS LATER TONIGHT AND DURING THE DAY ON THURSDAY. MAX SEAS ARE NOW EXPECTED TO BE AROUND 6 FEET. OUTLOOK... AS TROPICAL CYCLONE CRISTOBAL MOVES FARTHER AWAY FROM THE AREA, THE SWELLS ARE EXPECTED TO SUBSIDE. WHILE 5-FOOT SWELLS MAY PERSIST A LITTLE LONGER THURSDAY NIGHT, WE HELD OFF ON EXTENDING THE SMALL CRAFT ADVISORY ATTM DUE TO SOME UNCERTAINTY. HIGH PRESSURE BUILDS IN OVER THE WEEKEND BEFORE SHIFTING OFFSHORE AND ALLOWING FOR A RETURN FLOW INTO NEXT WEEK. THE FLOW MAY STRENGTHEN FOR A TIME SUNDAY INTO MONDAY, HOWEVER OVERALL THE CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA. && .RIP CURRENTS... LONG-PERIOD SWELLS FROM HURRICANE CRISTOBAL HAVE BEEN SLOWER TO REACH NJ AND DE BEACHES COMPARED TO WAVE MODEL GUIDANCE. HOWEVER...HIGHER SWELLS HAVE BEEN NOTED FARTHER SOUTH ALONG THE ATLANTIC COAST AND THESE ARE STILL EXPECTED TO SPREAD NWD OVER NIGHT AND CONTINUE ON THURSDAY AS CRISTOBAL CHURNS UP THE WATERS 500 MILES OR SO ESE OF DELAWARE BAY. THE HIGH RISK OF RIP CURRENTS HAS THEREFORE BEEN EXTENDED THROUGH THURSDAY INTO THURSDAY EVENING. THE MEDIA AND DECISION MAKERS CAN HELP. ALL 4 RIP CURRENT FATALITIES AT NJ BEACHES THIS YEAR WERE AT UNGUARDED LOCATIONS! THERE ISNT MUCH MORE WE CAN SAY EXCEPT THAT FAMILY MEMBERS AND FRIENDS MAY THINK THEY`RE STRONG ENOUGH TO KEEP YOU SAFE BUT ITS RISKY. LIKE IT OR NOT...THE WATER IS FAR MORE POWERFUL THAN YOU THINK. SWIMMING IN THE OCEAN IS NOT SWIMMING IN THE LOCAL POOL. ITS PROBABLY MORE TIRING BECAUSE OF LONG SHORE CURRENTS ALONG THE BEACH AND THE SWEEPING CRASHING MOTION OF THE WAVES BREAKING INWARD AND THEN THE OUTGOING WATER RETURNING TO SEA AS RIP CURRENTS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...HIGH RIP CURRENT RISK THROUGH THIS EVENING FOR NJZ014-024>026. DE...HIGH RIP CURRENT RISK THROUGH THIS EVENING FOR DEZ004. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS EVENING FOR ANZ450>455. && $$ SYNOPSIS...GORSE NEAR TERM...IOVINO SHORT TERM...KLEIN LONG TERM...GORSE AVIATION...GORSE/IOVINO MARINE...AMC/GORSE/KLEIN RIP CURRENTS...AMC/DRAG

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