Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 261604 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1204 PM EDT TUE AUG 26 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO INFLUENCE OUR WEATHER INTO WEDNESDAY. A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE WEDNESDAY NIGHT, FOLLOWED BY AN AREA OF HIGH PRESSURE FOR THURSDAY INTO SATURDAY. ANOTHER FRONTAL BOUNDARY FROM THE NORTHWEST IS EXPECTED TO DROP NEAR OR INTO OUR REGION SUNDAY AND MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A STRONG UPPER-LEVEL RIDGE REMAINS IN PLACE, HOWEVER IT IS FORECAST TO GRADUALLY FLATTEN THROUGH THE AFTERNOON. THIS IS DUE TO A SHORT WAVE TROUGH SLIDING FROM NEAR THE UPPER GREAT LAKES REGION ON NORTHWARD. AS THIS OCCURS, THE FLOW ALOFT WILL TEND TO BECOME MORE ZONAL. AT THE SURFACE, HIGH PRESSURE OVER THE REGION SHOULD BEGIN TO SHIFT SLOWLY EAST AND NORTHEASTWARD. THIS WILL RESULT IN A LIGHT FLOW REGIME, WITH THE SURFACE FLOW TENDING TO TURN FROM THE SOUTHWEST. AMPLE HEATING OF THE BOUNDARY LAYER THOUGH COMBINED WITH THE WEAKER WINDS WILL RESULT IN A CONTINUATION OF SEA/BAY BREEZE DEVELOPMENT THROUGH THE AFTERNOON. THE COASTAL OBSERVATIONS SHOW A LIGHT ONSHORE FLOW OCCURRING. THIS ONSHORE FLOW COMPONENT AT THE COAST WILL SPREAD INLAND SOME AND ALSO ACROSS PORTIONS OF THE DELMARVA. GIVEN THE PRESENCE OF HIGH PRESSURE AT THE SURFACE AND ALOFT ALONG WITH THE AIRMASS MODIFYING SOME MORE, A GOOD AMOUNT OF SUNSHINE IS FORECAST ALONG WITH WARM TEMPERATURES. THERE WILL BE A BIT OF CUMULUS ESPECIALLY TERRAIN INDUCED AND A TOUCH OF HIGH LEVEL CLOUDS AT TIMES. THE 12Z RAOBS FROM STERLING, VA AND UPTON, NY SHOW A DRY AIRMASS IN PLACE ESPECIALLY ABOVE ABOUT 850 MB. THE HOURLY GRIDS WERE ADJUSTED WITH THE LATEST OBSERVATIONS, THEN THE LAMP/LAV GUIDANCE WAS BLENDED IN TO HELP ASSIST WITH TRENDS. THE DEW POINTS SHOULD LOWER SOME FOR MOST LOCALES WITH AMPLE BOUNDARY LAYER HEATING, HOWEVER THIS MAY BE SLOWED SOME DUE TO REDUCED VERTICAL MIXING. NO MAJOR CHANGES WERE MADE TO THE HIGH TEMPERATURES ATTM.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... THE AFOREMENTIONED HIGH WILL REMAIN IN PLACE AND EXPECT A CLEAR AND PLEASANT NIGHT. HURRICANE CRISTOBAL WILL BE MOVG N OFF THE SERN CONUS COAST DURG THIS TIME. MDL GUID WAS IN GOOD AGREEMENT AND GENLY FOLLOWED. PLEASE SEE LATEST NHC ADVISORIES FOR THE LATEST INFORMATION ON CRISTOBAL. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... THE MID LEVEL RIDGE SHOULD BE IN THE PROCESS OF RETREATING ON WEDNESDAY MORNING WITH A MID LEVEL SHORT WAVE TROUGH FORECAST TO BE LOCATED OVER THE WESTERN GREAT LAKES. THE SHORT WAVE IS EXPECTED TO PROGRESS EASTWARD AND IT SHOULD PASS ACROSS THE NORTHEASTERN STATES ON WEDNESDAY NIGHT. THE FEATURE IS ANTICIPATED TO PUSH A SURFACE COLD FRONT THROUGH OUR REGION AT THAT TIME. AN AXIS OF VERY WARM AIR IS EXPECTED TO EXTEND INTO OUR FORECAST AREA ON WEDNESDAY AND IT SHOULD BE THE WARMEST DAY OF THE WEEK. TEMPERATURES AT 850 HPA ARE ANTICIPATED TO RISE INTO THE +17C TO +18C RANGE. AS A RESULT, MOST LOCATIONS WILL APPROACH OR HIT THE 90 DEGREE MARK WITH THE EXCEPTIONS BEING THE ELEVATED TERRAIN UP NORTH AND COMMUNITIES ALONG THE COAST. THE GUIDANCE CONTINUES TO INDICATE MARGINAL INSTABILITY AHEAD OF AND WITH THE SURFACE COLD FRONT. HOWEVER, MOISTURE SHOULD BE SOMEWHAT LIMITED. WE WILL CARRY A LOW OR SLIGHT CHANCE OF A SHOWER OR THUNDERSTORMS ACROSS THE NORTHERN THIRD OF OUR REGION FROM WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. HURRICANE CRISTOBAL SHOULD BE AT ITS CLOSEST TO OUR REGION ON WEDNESDAY NIGHT WHEN IT PASSES ABOUT 500 MILES TO OUR SOUTHEAST. IT WILL HAVE NO IMPACT ON OUR WEATHER BUT IT WILL LIKELY BRING INCREASED WAVE HEIGHTS AND LONG PERIOD SWELLS TO THE COASTS OF DELAWARE AND NEW JERSEY. THE NORTHWESTERLY MID LEVEL FLOW ON THURSDAY IN THE WAKE OF THE SHORT WAVE IS EXPECTED TO BRING DRY AIR INTO OUR REGION. THE MID LEVEL RIDGE IS FORECAST TO BEGIN BUILDING BACK OVER THE EASTERN STATES ON FRIDAY AND SATURDAY. HOWEVER, ANOTHER SHORT WAVE IS ANTICIPATED TO APPROACH FROM THE WEST ON SUNDAY AND MONDAY. SURFACE HIGH PRESSURE IS FORECAST TO KEEP OUR REGION RAIN-FREE FOR THURSDAY AND FRIDAY. THE CENTER OF THE SURFACE HIGH IS EXPECTED TO PASS OFF THE COAST ON FRIDAY WITH AN INCREASE IN HUMIDITY ANTICIPATED IN THE SOUTHERLY RETURN FLOW FROM FRIDAY NIGHT INTO SATURDAY. WE HAVE MENTIONED A SLIGHT CHANCE OF PRECIPITATION FOR SATURDAY. AS THE MID LEVEL TROUGH NEARS ON SUNDAY AND MONDAY IT MAY PUSH ANOTHER FRONTAL BOUNDARY FROM THE NORTHWEST TOWARD OR INTO OUR REGION. WE HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR BOTH DAYS. DAYTIME HIGHS ARE FORECAST TO RANGE MAINLY FROM THE UPPER 70S TO THE MIDDLE 80S FROM THURSDAY THROUGH MONDAY. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE 50S AND 60S FOR WEDNESDAY NIGHT, THURSDAY NIGHT AND FRIDAY NIGHT. MINIMUM READINGS SHOULD BE MOSTLY IN THE 60S FOR SATURDAY NIGHT AND SUNDAY NIGHT. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...VFR. LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST LESS THAN 10 KNOTS. A SEA/BAY BREEZE SHOULD AFFECT KACY, KMIV AND KILG WITH WINDS BECOMING MORE FROM THE SOUTHEAST. IF THE WINDS HOLD LIGHT ENOUGH, A MORE SOUTH-SOUTHEAST WIND MAY OCCUR AT KPHL. TONIGHT...VFR OVERALL. SOME LOCALIZED FOG IS POSSIBLE TOWARD MORNING, MAINLY AT KMIV AND KRDG. SOUTHERLY WINDS AROUND 5 KNOTS, BECOMING LIGHT AND VARIABLE OR CALM. WEDNESDAY....MAINLY VFR. AN ISOLATED LATE DAY SHOWER OR THUNDERSTORM IS POSSIBLE MAINLY NEAR KTTN, KABE AND KRDG. SOUTHWEST WINDS INCREASING TO 5-10 KNOTS. OUTLOOK... WEDNESDAY NIGHT...MAINLY VFR. A LOW OR SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE EVENING FROM AROUND KRDG, KABE AND KTTN NORTHWARD. THURSDAY THROUGH SATURDAY...MAINLY VFR.
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&& .MARINE... WITH ELY FLOW EVENTUALLY BECOMING MORE SLY AND DECREASES, SEAS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE NEAR AND SHORT TERM PDS AND NO MARINE HEADLINES ARE ANTICIPATED. OUTLOOK... WEDNESDAY THROUGH THURSDAY...WAVE HEIGHTS ON OUR OCEAN WATERS MAY BUILD TO 4 TO 6 FEET IN RESPONSE TO THE AFFECTS OF DISTANT HURRICANE CRISTOBAL. LONG PERIOD SWELLS OF 12 TO 16 SECONDS ARE POSSIBLE. THE WAVES AND THE LONG PERIOD SWELLS MAY CREATE HAZARDOUS CONDITIONS FOR SMALL CRAFT, ESPECIALLY AROUND THE INLETS ALONG THE COASTS OF DELAWARE AND NEW JERSEY. THURSDAY NIGHT THROUGH SATURDAY...NO MARINE HEADLINES ARE ANTICIPATED. && .RIP CURRENTS...
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THE RISK OF DANGEROUS RIP CURRENTS REMAINS ELEVATED THROUGH A GOOD PORTION OF THE WEEK. WIND AND WAVES HAVE DECREASED TODAY COMPARED TO YESTERDAY AND SO HAS THE WINDS WITH HIGH PRESSURE OVER THE AREA. THE WAVE PERIOD THOUGH IS AROUND 8 SECONDS WHICH WILL RESULT IN ROUGH CONDITIONS AT TIMES IN THE SURF ZONE. THIS ALL COMBINED RESULTS IN A MODERATE RISK OF DANGEROUS RIP CURRENTS THROUGH THIS EVENING. BASED ON THE LATEST TRACK AND INTENSITY FORECAST OF HURRICANE CRISTOBAL FROM NHC, CONDITIONS COULD BECOME HIGH AGAIN WEDNESDAY AND THURSDAY AS CRISTOBAL TRACKS WELL EAST OF THE MID ATLANTIC COAST.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...IOVINO NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...IOVINO AVIATION...GORSE/IOVINO MARINE...IOVINO/NIERENBERG RIP CURRENTS...GORSE/NIERENBERG

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