Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 240916 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 516 AM EDT MON AUG 24 2015 .SYNOPSIS... A COLD FRONT ENTERING WESTERN PENNSYLVANIA WILL MOVE INTO OUR AREA TONIGHT AND OFF THE COAST TUESDAY AFTERNOON, POSSIBLY WITH WEAK LOW PRESSURE FORMING ON THE FRONT OVER NEW JERSEY TUESDAY MORNING. HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR WEDNESDAY INTO FRIDAY, BEFORE SHIFTING OFFSHORE DURING THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SOME PATCHY FOG HAS DEVELOPED OVERNIGHT ACROSS SRN NJ AND SE PA. IT IS NOT EXPECTED TO BECOME WIDESPREAD ENOUGH OR THICK ENOUGH TO WARRANT ANY FLAGS...BUT LOCAL VSBYS OF 3/4 TO 2 MI CAN BE EXPECTED A TIMES. A WARM AND HUMID DAY IS EXPECTED ACROSS THE AREA AS WEAK HIGH PRESSURE REMAINS OFFSHORE AND A COLD FRONT APPROACHES FROM THE WEST. WINDS WILL BE MOSTLY SRLY OR SERLY TODAY...AND THIS WILL AID IN BRINGING IN HIGHER DEW POINTS ACROSS THE AREA. OVERALL...IT WILL NOT FEEL TOO UNCOMFORTABLE...BUT STILL MORESO THAN OVER THE WEEKEND. HIGH TEMPERATURES TODAY WILL BE IN THE MID/UPPER 80S IN MOST AREAS AND DEW POINTS WILL BE IN THE LOW 60S N/W AND MID/UPPER 60S S/E. THE FRONT MAY TRIGGER A FEW SCT SHOWERS AND TSTMS ACROSS THE N/W AREAS BY LATER IN THE AFTERNOON. POPS S/E OF THE DEL VALLEY WILL BE HELD ONLY IN THE SLGT CHC RANGE ATTM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... SCT SHOWERS AND A FEW TSTMS WILL CONTINUE TO MOVE FROM W TO E OVERNIGHT ALONG THE COLD FRONT...HIGHER CHC POPS WILL BE ACROSS THE NRN AREAS WITH LESSER POPS OVER THE DELMARVA. AN OVERALL 1/10 TH TO 1/4 INCH OF RAIN IS EXPECTED. SVR TSTMS ARE NOT EXPECTED WITH RATHER WEAK WIND FIELDS AND LIMITED CAPES. LOWER DEW POINTS WILL MOVE IN FROM THE W LATE. LOWS TONIGHT WILL REMAIN MILD IN MOST AREAS WITH UPPER 60S AND LOW 70S IN MOST AREAS AND SOME LOW/MID 60S FAR NW. && .LONG TERM /TUESDAY THROUGH SUNDAY/... 500 MB: A TROUGH IN THE EASTERN UNITED STATES WILL BE ANCHORED BY A MID LEVEL LOW JUST NORTH OF THE GREAT LAKES. IT WEAKENS BY THE WEEKEND WITH A REMNANT TROUGH LEFT BEHIND IN THE SOUTHEAST USA, CONFLUENT WITH ZONAL FLOW OF SOMEWHAT WARMER THAN NORMAL HEIGHTS ACROSS THE NORTHEAST STATES. TEMPERATURES: CALENDAR DAY AVERAGES ABOUT 4 DEGREES ABOVE NORMAL TUESDAY THEN WITHIN 2 OR 3 DEGREES OF NORMAL WEDNESDAY-FRIDAY FOLLOWED BY A SLIGHT WARMING TREND NEXT WEEKEND. FORECAST BASIS: UNLESS OTHERWISE NOTED, A 50 50 BLEND 00Z/24 GFS/NAM MOS GUIDANCE TUESDAY-WEDNESDAY, 00Z/24 MEX MOS WEDNESDAY NIGHT AND THURSDAY, THEN THE 0441Z/24 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12 HOUR POP, 6 HOUR DEWPOINT-SKY-WIND FROM THURSDAY NIGHT THROUGH NEXT SUNDAY. THIS LOOKS TO BE A RAINFREE WEEK AFTER WHATEVER SHOWERS OCCUR TONIGHT AND TUESDAY MORNING. THE DAILIES... TUESDAY...MAYBE LINGERING SHOWERS EARLY IN THE DAY, ESPECIALLY COASTAL NJ...OTHERWISE BECOMING PARTLY TO MOSTLY SUNNY AND WARM. SREF PWAT TO START THE DAY DOWN TO 1.25 INCHES I-95 CORRIDOR, LESS TO THE WEST AND THEN DRIES TO 0.9 INCHES BY DAYS END. WINDS BECOME MOSTLY WEST WITH GUSTS UNDER 15 MPH. CONFIDENCE: AVERAGE TUESDAY NIGHT...CLEAR WITH PATCHY FOG POSSIBLE LATE? UPS CROSSOVER TOOL USED GENERATE THE FOG IN NNJ. CONFIDENCE: ABOVE AVERAGE. WED-FRI...DIURNAL CU/SC AS A COOL POOL ARRIVES WITH THE TROUGHING ALOFT AND TEMPS SEASONABLY COOL. MLCAPE ALMOST NIL. NO CHANGE IN PRIOR EXPECTATIONS FROM YDYS DAY SHIFT. WEAK IMPULSES IN THE MID LEVEL FLOW MAY HELP TO ENHANCE THE AMOUNT OF CUMULUS OVER OUR NORTHERN COUNTIES ON WEDNESDAY AFTERNOON AND THURSDAY AFTERNOON. VERY WEAK INSTABILITY IN THE NORTH COULD RESULT IN SCATTERED SPRINKLES THERE. MEANWHILE, THE NIGHTS SHOULD BE MAINLY CLEAR WITH PERHAPS SOME LATE NIGHT VALLEY FOG DEVELOPING IN EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. CONFIDENCE: ABOVE AVERAGE. THIS COMING WEEKEND...PARTLY SUNNY AND SLOWLY WARMING. A SMALL CHANCE THAT A BAND OF SHOWERS AND TSTMS CROSSES THE REGION IN THE WAA PATTERN AHEAD OF THE TROF AXIS. IF THIS SHOWER EVENT WERE TO OCCUR, IT PROBABLY WOULD BE LATER IN THE WEEKEND. CONFIDENCE: AVERAGE. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE AIRMASS ACROSS SRN NJ AND SE PA HAS BECOME RATHER HUMID OVERNIGHT AND LIGHT FOG HAS ALREADY BEEN OBSERVED AT A FEW LOCATIONS. WE HAVE INCLUDED SOME TEMPO GROUPS FOR FOG IN THE AREAS DEEMED MORE LIKELY TO SEE IT THIS MORNING...BASED ON T/TD SPREADS AND CLOUD COVER. THE BALANCE OF THE DAYLIGHT HOURS MON WILL HAVE VFR CONDITIONS ALONG WITH SOUTH TO SOUTHWEST WINDS AHEAD OF AN APPROACHING COLD FRONT. CLOUD COVER WILL BE MOSTLY FEW-SCT CU AND SOME SCT-BKN AC INCREASING THRU THE DAY. WINDS WILL TEND TO BECOME MORE SRLY AS THE DAY PROGRESSES. THERE MAY BE MORE OF AN ONSHORE WIND AT KACY...MORE SO THAN INDICATED IN THE TAF...CONFID IN A PURE SEA-BREEZE IS LIMITED. TONIGHT...THE COLD FRONT WILL CROSS THE WRN AREAS AROUND 05Z/06Z THEN PROGRESS EASTWARD REACHING THE DEL VALLEY AROUND 10Z THEN THE COAST PERHAPS AROUND 12Z. THE FRONT WILL BE SLOWING/WEAKENING AS IT MOVES THROUGH. SCT SHOWERS ARE EXPECTED WITH PSBL THUNDER (LOW CONFID...NOT IN TAFS). WINDS WILL SHIFT WRLY/NWRLY BEHIND IT. OUTLOOK... TUESDAY...A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WHICH MAY LOWER CONDITIONS INTO THE MVFR OR IFR CATEGORIES AT TIMES DURING THE MORNING AND MAINLY COASTS. BECOMING VFR IN THE AFTERNOON WITH WESTERLY GUSTS UNDER 15 KT. CONFIDENCE: AVERAGE. TUESDAY NIGHT...MAINLY VFR WITH PATCHY LOW CLOUDS AND FOG POSSIBLE AFTER 06Z/26. CONFIDENCE: ABOVE AVERAGE WEDNESDAY THROUGH FRIDAY...MAINLY VFR WITH DIURNAL SCT CLOUDS AOA 5000 FT. CONFIDENCE: ABOVE AVERAGE. && .MARINE... WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CONDITIONS TODAY AND TONIGHT. WINDS WILL BE LIGHT AND SOMEWHAT VARIABLE EARLY THIS MORNING BEFORE A SRLY/SWRLY FLOW AT 5 TO 10 KNOTS DEVELOPS ON THE WATERS LATER THIS MORNING. WINDS WILL INCREASE CLOSER TO 10-12 KNOTS AND TURN MORE SRLY TONIGHT AS A COLD FRONT APPROACHES. THE FRONT WILL BE ACCOMPANIED BY SCT SHOWERS AND TSTMS. SVR TSTMS ARE NOT EXPECTED. WINDS WILL TURN WRLY/NWRLY BEHIND THE FRONT TOWARDS DAWN TUE. OUTLOOK... MONDAY NIGHT THROUGH FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED. OUTLOOK... TUESDAY THROUGH FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED. JUST AN ESE 2 FT SWELL OF 10 TO 12 SECONDS ON THE ATLC WATERS WITH A LITTLE WIND WAVE ON TOP. && .RIP CURRENTS... SHOULD BE LOW ENHANCED MUCH OF THE WEEK WITH A LONGER PERIOD SWELL EXPECTED TO BECOME DOMINANT TUESDAY ONWARD. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG NEAR TERM...O`HARA SHORT TERM...O`HARA LONG TERM...DRAG AVIATION...DRAG/O`HARA MARINE...DRAG/O`HARA RIP CURRENTS...

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