Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 131546 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1146 AM EDT SAT SEP 13 2014 .SYNOPSIS... LOW PRESSURE OVER THE EASTERN GREAT LAKES AND LOW PRESSURE EAST OF DELAWARE WILL MOVE NORTHEAST TODAY AND SEND A COLD FRONT EASTWARD AND OFF THE MID ATLANTIC COAST THIS EVENING. HIGH PRESSURE FROM THE MIDWEST WILL THEN BUILD EASTWARD THROUGH THE MID ATLANTIC STATES FOR SUNDAY AND MONDAY. A QUICK-MOVING COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY NIGHT INTO TUESDAY, FOLLOWED BY MORE HIGH PRESSURE BUILDING OVER THE MID ATLANTIC THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1125 AM ESTF EARLY UPDATE: RAISED RAIN PROBS NJ AND THE DELMARVA THIS AFTN PER MODEL GUIDANCE...WHAT APPEARS TO BE INCREASING RADAR COVERAGE UPSTREAM AND 09Z 3 HRLY SREF PROBS AS WELL AS A DECENT INSTABILITY BURST IN NJ WITH PWAT INCREASING FROM THE 12Z ~1.25 INCHES TO 18Z ~ 1.9 INCHES. AS THE SHOWERS BECOME MORE WIDESPREAD THIS AFTN IN NJ/DELAWARE WHILE THE SHOWERS WILL EVENTUALLY END AS BAROCLINIC NE SW BAND CURRENTLY HEADING EWD ACROSS CENTRAL PA. TEMPS WILL STRUGGLE TO RISE MUCH PAST 55 IN THE POCONOS AND 60S ELSEWHERE IN PA...70 OVER THE I95 CORRIDOR AND MID 70S PORTIONS OF THE COAST. THIS IS GENERALLY 5 TO 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. TONIGHT...BAROCLINIC ZONE SCT SHOWERS WILL BE ENDING FROM WEST TO EAST THIS EVENING. SKIES WILL CLEAR TONIGHT AND THE REST OF THE NIGHT LOOKS DRY AND PLEASANTLY COOL WITH TEMPS DROPPING INTO THE 40S AND 50S. A BIT OF A NNW BREEZE MAY DEVELOP IN THE GRADIENT ISOBARIC NORTHERLY FLOW. && .SHORT TERM /SUNDAY/... BRILLIANT SUNSHINE AND PLEASANT, 5 DEGREE BELOW AVERAGE DAYTIME TEMPERATURES ARE IN STORE, WITH HIGHS RANGING FROM THE 60S THROUGH THE SOUTHERN POCONOS AND PARTS OF NORTHWEST NJ TO MAINLY THE LOWER 70S ELSEWHERE. SOME AFTERNOON STRATOCU CLOUDINESS SHOULD FORM IN THE NE PA HILLS AND MOUNTAINS AS WELL AS NW NJ. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A NICE CLOSE TO THE WEEKEND IS IN STORE FOR OUR REGION AS THE QUICK MOVING LOW PRESSURE AND UPPER-LEVEL TROUGH WILL BE PROGRESSING FROM NORTHERN NEW ENGLAND TO THE CANADIAN MARITIMES BY SUNDAY MORNING AS HIGH PRESSURE FROM THE MIDWEST STATES EXPANDS EASTWARD INTO THE MID ATLANTIC. TEMPERATURES WILL TEND TO MODERATE SOMEWHAT GOING INTO MONDAY AS THE HIGH PRESSURE GRADUALLY MOVES OFFSHORE, WITH DAYTIME READINGS JUST A COUPLE OF DEGREES WARMER. GOING INTO MONDAY NIGHT, A RATHER QUICK MOVING UPPER SHORTWAVE IS FORECAST TO TRACK EASTWARD FROM AROUND THE GREAT LAKES LATE MONDAY, PASSING OVER OUR REGION INTO EARLY TUESDAY. AN ASSOCIATED WEAK SURFACE LOW IS ALSO PROGGED TO DEVELOP AS THE SHORTWAVE MOVES EAST. OVERALL, THE ECMWF IS A BIT STRONGER WITH THE UPPER SHORTWAVE AND SUBSEQUENT SURFACE LOW AS COMPARED TO THE GFS, WITH POSSIBLY A LITTLE MORE PRECIP AFFECTING OUR REGION FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING, AND WE HAVE KEPT SOME HIGH CHANCE POPS IN PLACE AT THIS TIME. WHILE SCATTERED SHOWERS LOOK TO BE IN THE PICTURE AT THIS TIME FOR TUESDAY MORNING, SOME IMPROVEMENT WITH DECREASING POPS IS EXPECTED FOR TUESDAY AFTERNOON AND EVENING, AS THE SYSTEM PROGRESSES EAST AND OFFSHORE, AND HIGH PRESSURE FROM ACROSS THE PLAINS AND MIDWEST EXPANDS EASTWARD INTO OUR REGION. FOR THE WEDNESDAY THROUGH FRIDAY TIMEFRAME, OUR REGION WILL MOSTLY BE INFLUENCED BY A LARGE AREA OF SURFACE HIGH PRESSURE AND A BROAD UPPER-LEVEL TROUGH. SOME MODEL GUIDANCE INDICATES A POSSIBLE WEAK COLD FRONT PASSING ACROSS THE REGION THURSDAY, BUT THERE IS LITTLE MOISTURE ASSOCIATED WITH THIS BOUNDARY. AT THIS TIME, WE MOSTLY TOOK A WPC/CONTINUITY BLEND, KEEPING A PRECIP-FREE FORECAST THROUGH THIS PERIOD. TEMPERATURES OVERALL LOOK TO BE SLIGHTLY BELOW AVERAGE THROUGH THIS PERIOD, WITH DAYTIME HIGHS RANGING FROM THE 60S IN THE POCONOS TO THE LOWER/MID 70S ELSEWHERE AND NIGHTTIME LOWS RANGING FROM THE 40S NORTH TO THE MIDDLE 50S SOUTH. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...MOSTLY MVFR CIGS WITH OCNL 3-5 MI VSBY IN SHOWERS. LIGHT NE WIND G 10-15 KT. TONIGHT...VFR CIGS EARLY WITH POSSIBLE LEFT MVFR CIGS THEN BECOMING CLEAR BY 04Z/14 WITH JUST A SMALL CHC OF PATCHY MVFR FOG FOR A SHORT TIME. NNW WIND MAY BECOME GUSTY 15 KT LATE. SUNDAY...VFR MOSTLY CLEAR CONDITIONS WITH A LIGHT NORTH-NORTHWEST WIND. OUTLOOK... MONDAY THROUGH TUESDAY...MAINLY VFR. SOME SCATTERED SHOWERS ARE POSSIBLE LATE MONDAY NIGHT THROUGH TUESDAY MORNING, WITH SUB-VFR CONDITIONS. WEDNESDAY...VFR CONDITIONS. && .MARINE... WINDS AND SEAS ARE FCST TO REMAIN JUST BELOW SCA CRITERIA THIS THROUGH EARLY AFTERNOON AS A COASTAL LOW TAKES SHAPE AND HEADS NE. GUSTS AROUND 25 HAVE3 OCCURRED AROUND BRICK AND SANDY HOOK BUT OVERALL THE WEATHER FLOW DATA TRENDS ARE SLIGHTLY LOWER SINCE 15Z. SCA MAY BE NEEDED FROM MIDNIGHT ONWARD LATE TONIGHT IN THE GRADIENT NNW COOL AIR ADVECTION BEHIND THE COLD FRONT. HOWEVER, CONFIDENCE IS NOT THAT HIGH FOR AN SCA AND THE WINDOW THAT THIS WILL OCCUR IS SHORT SO WILL HOLD OFF ANY SCA ISSUANCE`S ATTM. SUNDAY...POSSIBLE MARGINAL SCA CONDITIONS FOR THE COASTAL WATERS. CONFIDENCE BELOW AVERAGE. THE GRADIENT BETWEEN A DEPARTING SYSTEM TO THE NORTHEAST AND INCOMING HIGH PRESSURE TO OUR WEST MAY YIELD SOME WIND GUSTS BETWEEN 20 TO 25 KNOTS AND SEAS INTO THE 4 FOOT RANGE FOR OUR ATLANTIC COASTAL WATERS THROUGH SUNDAY MORNING. WINDS AND SEAS ARE EXPECTED TO DECREASE, THOUGH, INTO SUNDAY AFTERNOON AS HIGH PRESSURE BUILDS OVER THE REGION AND AREA WATERS. OUTLOOK... MONDAY THROUGH TUESDAY...WHILE A QUICK-MOVING SYSTEM MAY BRING SOME SCATTERED SHOWERS LATE MONDAY NIGHT THROUGH TUESDAY MORNING, WINDS AND SEAS OVERALL LOOK TO REMAIN AT SUB-ADVISORY LEVELS. WEDNESDAY...WINDS/GUSTS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA, BUT SEAS MAY BUILD TOWARD 5 FEET, ESPECIALLY FOR OUR OUTER COASTAL WATERS. && .RIP CURRENTS... THERE IS A MODERATE RISK OF RIP CURRENTS TODAY. && .CLIMATE... IT SEEMS WORTHWHILE TO NOTE THAT THE PRECIPITATION ACCUMULATION DEPARTURE FROM NORMAL THE PAST TWO WEEKS (NOT INCLUDING TODAY) IS WELL BELOW NORMAL FOR E PA AND NW NJ AS WELL AS CENTRAL DE. FOR NW NJ AND CENTRAL-SRN DE THAT MIRRORS THE 90 DAY ANALYSIS OF 50 TO 75 PCT OF NORMAL PCPN THIS PAST SUMMER. THE 46 MEMBER NAEFS HAS NOT DONE SO WELL ON MODELING THE SUBSTANTIAL 4 DEGREE OR GREAT POSITIVE TEMPERATURE ANOMALY THAT HAS OCCURRED HERE IN THE NORTHEASTERN QUADRANT OF THE COUNTY THE FIRST 12 DAYS OF THE MONTH...YET DOING WELL IN THE PLAINS AND NORTHERN ROCKIES AS WELL AS GULF COAST. THE NAEFS HAS HAD A RECENT SIGNIFICANT COLD BIAS IN OUR AREA. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG/KLINE NEAR TERM...DRAG 1146 SHORT TERM...DRAG 1146 LONG TERM...KLINE AVIATION...DRAG/KLINE 1146 MARINE...DRAG/KLINE 1146 RIP CURRENTS... CLIMATE...

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