Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 210357 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1157 PM EDT WED MAY 20 2015 .SYNOPSIS... WEAK HIGH PRESSURE PREVAILS OVER THE MID ATLANTIC STATES THROUGH EARLY THURSDAY. LOW PRESSURE INN THE CAROLINAS WILL STRENGTHEN AS IT MOVES NORTHEASTWARD OUT TO SEA THURSDAY EVENING. A WEAK COLD FRONT WILL CROSS THE AREA FRIDAY, FOLLOWED BY HIGH PRESSURE RETURNING ACROSS THE REGION FRIDAY NIGHT THROUGH SATURDAY, BEFORE PROGRESSING OFFSHORE SUNDAY. ORGANIZING LOW PRESSURE ACROSS THE CENTRAL UNITED STATES WILL ALLOW A WARM FRONT TO LIFT NORTH THROUGH THE REGION MONDAY, AND A COLD FRONT IS FORECAST TO APPROACH FROM THE WEST TUESDAY. && .NEAR TERM /THROUGH THURSDAY/... 1230 AM ESTF: OVERNIGHT...VERY LITTLE CHANGE ANTICIPATED. VARIABLE HIGH CLOUDS THICKEN AND SEAL FROM MUCH ADDITIONAL RADIATIONAL COOLING AFTER 08Z. A BIT MORE BREEZE THAN ANTICIPATED OVERNIGHT (AS WAS ON WEDNESDAY OVER DE BAY) WITH THE NORTHWEST WIND TURNING NORTH-NORTHEAST BY MORNING. NO FROST EXPECTED THURSDAY...THE NAM TRENDED SEWD ON THIS 00Z CYCLE. NO CONCLUSIONS YET ON THIS SHIFT REGARDING NORTHERN EXTEND OF THE DELMARVA RAINSHIELD. WE DO ANTICIPATE A MOSTLY CLOUDY COOL DAY. EASTERLY FLOW TO START THE DAY WITH FLOW TURNING S OR SW ACROSS THE NORTH DURING THE AFTN AND REMAINING EASTERLY IN THE FAR SOUTH. PER YESTERDAYS DAY SHIFT: WE HAVE BROUGHT THE CHANCE OF RAIN AS FAR NORTH AS INTERSTATE 78 AND WE MENTION THE LIKELIHOOD OF RAIN FOR MUCH OF NORTHEASTERN MARYLAND, DELAWARE AND SOUTHERN NEW JERSEY. IT APPEARS AS THOUGH RAINFALL AMOUNTS OF 0.25 TO 0.75 INCHES WILL FALL ACROSS OUR SOUTHERN COUNTIES. ABOUT A TENTH OF AN INCH MAY FALL AS FAR NORTH AS PHILADELPHIA WITH LESSER AMOUNTS NORTH OF THERE. THE CLOUD COVER WILL PROBABLY KEEP TEMPERATURES FROM GETTING MUCH ABOVE 60 DEGREES IN MOST OF OUR FORECAST AREA (EC WAS FLAGGING THIS MUCH COOLER SCENARIO ON THE 00Z/19 CYCLE WHEN COMPARED TO THE MUCH MILDER NCEP MOS FROM THAT 00Z/19 CYCLE). ACTUALLY, THE WARMEST TEMPERATURES IN OUR REGION ON THURSDAY MAY BE IN OUR NORTHERN VALLEYS WHERE HIGHS MAY GET INTO THE MIDDLE 60S. && .SHORT TERM /THURSDAY NIGHT/... FROM THE 330 PM WEDNESDAY FORECAST DISCUSSION BELOW: TO START THE LONG TERM, A WEAK AREA OF LOW PRESSURE IS FORECAST TO BE EMERGING OFF THE MIDDLE ATLANTIC COAST THURSDAY EVENING/NIGHT IN THE VICINITY OF THE NORTH CAROLINA/VIRGINIA BORDER. THIS WEAK LOW PRESSURE IS THEN PROGGED TO TRACK NORTHEAST AND OUT TO SEA DURING THE OVERNIGHT HOURS. THERE CONTINUE TO BE A FEW MODEL DIFFERENCES WITH REGARDS TO EXACTLY WHERE THIS LOW PRESSURE EMERGES OFF THE COAST, FROM AROUND THE VIRGINIA TIDEWATER OR A BIT FARTHER SOUTH OFF THE NORTH CAROLINA COAST. SOME DIFFERENCES ALSO EXIST WITH REGARDS TO MODELED QPF, WITH THE NAM BEING A WETTER SOLUTION AS COMPARED TO THE GFS AND ECMWF, AND ITS TRACK ALSO BEING THE MORE NORTHERN SOLUTION. NONETHELESS, OVERALL TREND THROUGH LATE THURSDAY EVENING AND NIGHT WILL BE FOR PRECIP TO BE TAPERING OFF FROM NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA, AS WE HANG ON TO CHANCE POPS THE LONGEST ALONG THE SOUTHERN NJ COAST AND THROUGH OUR SOUTHERN DELMARVA ZONES. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... ANOTHER WEAK SURFACE LOW PRESSURE WILL BE TRACKING TOWARD NORTHERN NEW ENGLAND AND THE CANADIAN MARITIMES THROUGH THE DAYTIME FRIDAY, WITH ITS ASSOCIATED COLD FRONT EXPECTED TO CROSS OUT REGION FRIDAY AFTERNOON TO EVENING. WITH VERY LIMITED MOISTURE, WE HAVE MAINTAINED A DRY FORECAST FRIDAY; ALTHOUGH, WEST- NORTHWEST WINDS WILL PICK UP IN THE WAKE OF THIS FRONT AS THE PRESSURE GRADIENT TIGHTENS FOR A TIME. WINDS THEN RELAX LATER FRIDAY NIGHT AND THROUGH SATURDAY AS AN AREA OF HIGH PRESSURE BUILDS EASTWARD FROM THE MIDWEST STATES. A COOL FRIDAY NIGHT WITH BELOW AVERAGE TEMPERATURES IS ANTICIPATED FOR OUR AREA, WITH CLEARING SKIES AND LIGHT WINDS. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 50S IN THE SOUTHERN DELMARVA TO THE LOWER 40S ACROSS OUR NORTHERN ZONES AND PERHAPS EVEN SOME 30S AND PATCHY FROST INTO THE HIGHER TERRAIN OF THE POCONOS. LIGHT WINDS, AMPLE SUN, AND NEAR AVERAGE MAY TEMPERATURES ARE EXPECTED FOR OUR AREA WITH HIGH PRESSURE PASSING OVER THE REGION SATURDAY. WHILE SUNDAY WILL STILL BE PLEASANT, TEMPERATURES AND DEWPOINTS WILL BE CREEPING UPWARD A FEW DEGREES AS THE AREA OF HIGH PRESSURE EASES OFFSHORE AND A RETURN SOUTHWESTERLY FLOW SETS UP OVER THE REGION. THIS WARMING TREND AND GRADUAL INCREASE IN DEWPOINTS WILL CONTINUE THEN INTO MONDAY AS AN AREA OF LOW PRESSURE IS FORECAST TO ORGANIZE OVER THE CENTRAL UNITED STATES, WITH ITS ASSOCIATED WARM FRONT LIFTING NORTH THROUGH THE OHIO VALLEY AND OUR REGION MONDAY. THERE SHOULD BE ENOUGH LIFT AND INSTABILITY AS THIS BOUNDARY PASSES NORTH FOR SOME SCATTERED SHWR/TSTORM ACTIVITY ACROSS OUR REGION, AND WE HAVE KEPT CHANCE POPS IN PLACE FOR MEMORIAL DAY, SOMEWHAT HIGHER CHANCES FOR THE NORTHERN TWO-THIRDS OF THE FORECAST AREA. A MORE NOTICEABLE INCREASE IN WARMTH AND HUMIDITY IS THEN EXPECTED GOING INTO TUESDAY AS OUR REGION WILL BE IN THE WARM SECTOR, WITH THE SURFACE LOW AND WARM FRONT TO OUR NORTH. BUILDING INSTABILITY AND A COLD FRONT APPROACHING FROM THE WEST WILL YIELD MORE SCATTERED SHWR/TSTORM POTENTIAL, AND WE KEPT SOME CHANCE POPS IN PLACE THROUGH THIS TIMEFRAME. DAYTIME TEMPERATURES SHOULD EASILY REACH INTO THE MIDDLE AND UPPER 80S FROM THE DELAWARE VALLEY INTO THE DELMARVA, WITH SOMEWHAT COOLER UPPER 70S/LOW 80S FARTHER NORTH AND ALONG THE COAST. A LITTLE MORE UNCERTAINTY EXISTS INTO WEDNESDAY WITH REGARDS TO ISOLATED/SCATTERED PRECIP POTENTIAL DEPENDING ON THE PROGRESS OF THE FRONTAL BOUNDARY, AND FOR NOW, WE INTRODUCED SOME VERY LOW POPS INTO THE FORECAST FOR THE WEDNESDAY TIMEFRAME. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THROUGH 12Z THURSDAY...VFR. AREAS OF CIGS AOA 20000 FT LOWER TO NEAR 10000 FT AT 12Z. WIND NNW BECOMING NNE WITH GUSTS 10-15 KT FROM THE I-95 CORRIDOR EASTWARD INCLUDING KPHL GROUP OF TAFS. AFTER 12Z THURSDAY...VFR CIGS. LIGHT RAIN IS FORECAST TO SPREAD INTO OUR REGION FROM THE WEST AND SOUTHWEST AROUND 1500Z. THE RAIN IS EXPECTED TO REMAIN SOUTH OF KRDG AND KABE. LIGHT RAIN IS ANTICIPATED FOR KILG, KPHL, KPNE AND KTTN DURING THE AFTN. CONDITIONS SHOULD REMAIN IN THE VFR CATEGORY AT THOSE LOCATIONS WITH CEILINGS STAYING ABOVE 3000 FEET AND VISIBILITY VALUES STAYING ABOVE 5 MILES. THE RAIN IS FORECAST TO HAVE A GREATER IMPACT ON KMIV AND KACY THAN ON OUR TAF SITES TO THE NORTH. CONDITIONS MAY DROP TO MVFR AT KMIV AND KACY ON THURSDAY AFTERNOON. A LIGHT SOUTHWEST WIND MAY DEVELOP AT KRDG, KABE, KTTN, KPNE, KPHL AND KILG. THE WIND MAY REMAIN VARIABLE AT KMIV AND KACY OR IT COULD SETTLE INTO THE NORTHEAST OR EAST DURING THE AFTERNOON HOURS AT THOSE LOCATIONS. THURSDAY NIGHT...MOSTLY VFR; ALTHOUGH, SOME LINGERING RAIN/SHWRS MAY MEAN SOME SUB-VFR THROUGH THE FIRST PART OF THE NIGHT MAINLY FROM AROUND KMIV/KACY AND SOUTH. OUTLOOK... FRIDAY...VFR CONDITIONS ARE EXPECTED WITH WEST-NORTHWEST WINDS GUSTING TO AROUND 20 KNOTS DURING THE AFTERNOON. SATURDAY...CONTINUED VFR WITH LIGHT NORTHWEST WINDS. SUNDAY...VFR CONDITIONS WITH SOUTHWEST WINDS 10 TO 15 KNOTS. MONDAY...MAINLY VFR WITH LIGHT SOUTHWEST WINDS; ALTHOUGH, SOME SCATTERED SHWRS/TSTORMS AND SUB-VFR POSSIBLE AT TIMES. && .MARINE... SAFE BOATING WEEK CONTINUES THROUGH FRIDAY MORNING. THERE IS A USCG SAFETY APP THAT SHOULD BE OF VALUE TO MARINERS AND WAS JUST UNVEILED THIS WEEK: HTTP://WWW.USCG.MIL/MOBILE. THIS APP PROVIDES ADDITIONAL SAFE BOATING RESOURCES FOR MOBILE DEVICE USERS. WHEN LOCATION ENABLED, USERS CAN RECEIVE THE LATEST WEATHER REPORTS FROM THE CLOSEST NOAA BUOY AS WELL AS REPORT THE LOCATION OF A HAZARD ON THE WATER. IT FEATURES AN EMERGENCY ASSISTANCE BUTTON, WHICH CAN CALL THE CLOSEST CG COMMAND CENTER. THE FORECAST: NO MARINE HEADLINE ANTICIPATED THROUGH THURSDAY NIGHT THOUGH IT MAY BE A CLOSE CALL FOR THE ATLANTIC DE WATERS THURSDAY NIGHT FOR A MARGINAL SCA. NORTHERLY WINDS OVERNIGHT TEND NORTHEAST NORTHEAST-EAST BY DAYBREAK THURSDAY THEN ONSHORE SOUTHEAST THURSDAY AFTERNOON. WINDS BECOMING NORTHWEST THURSDAY NIGHT. OUTLOOK... FRIDAY...WHILE WE HAVE NO HEADLINE ANTICIPATED AT THIS TIME THERE IS SMALL POTENTIAL FOR AN SCA WEST-NORTHWEST FLOW LATE FRIDAY OR FRIDAY NIGHT. SATURDAY AND SUNDAY...CONTINUED SUB-ADVISORY CONDITIONS; ALTHOUGH, SOME WIND GUSTS TO AROUND 20 KNOTS STILL POSSIBLE AT TIMES. MONDAY...SUB-ADVISORY ANTICIPATED AT THIS TIME. SOME SCATTERED SHWRS/TSTORMS EXPECTED WITH LOCALLY HIGHER WINDS/SEAS NEAR TSTORMS. && .FIRE WEATHER... FOR FRIDAY AFTERNOON, THERE MAY BE THE RISK FOR ENHANCED WILDFIRE SPREAD AS A WEST-NORTHWESTERLY WIND GUSTS TO BETWEEN 20 TO 25 MPH AT TIMES. IN ADDITION, THIS WILL COMBINE WITH RELATIVE HUMIDITY VALUES NEARING 30 PERCENT IN SOME AREAS ALONG WITH DRY FINE FUELS. && .RIP CURRENTS... SST`S ABOVE NORMAL AND JUST OFF THE COAST SSTS WELL ABOVE NORMAL BY ALMOST 3C. THIS IS NOT GOOD ONCE IT TURNS HOT AND BEACHES ARE UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE SMART ABOUT ANY SWIMMING EARLY THIS SEASON. ATLANTIC COASTAL WATER TEMPS ARE WARMING --UPPER 50S TO MID 60S. RIP CURRENT AWARENESS WEEK FOR MT HOLLY IS JUNE 7-13 WITH PSAS VIA PUBLIC INFORMATION STATEMENTS, SOCIAL MEDIA, NOAA WEATHER RADIO AND ANY MEDIA INTERVIEWS DESIRED (CONTACT OFFICE). FOR RIP CURRENTS: DESPITE ANTICIPATED PROJECTIONS OF LOW OR MODERATE RISK THROUGH THE MEMORIAL DAY WEEKEND, EARLY SEASON FATALITIES OCCUR WHEN SWIMMING AT UNGUARDED TIMES/LOCATIONS. WEAKER SWIMMERS OR SWIMMING IN AREAS WHERE RIP CURRENTS ARE STRONGER (JETTIES) CAN QUICKLY BECOME LIFE THREATENING. WHEN TRAINED LIFEGUARDS ARE NOT NEARBY, TIMELY RESCUE IS MUCH LESS LIKELY. LETS GET THROUGH THE MONTH OF MAY WITH ALL SWIMMERS SAFE! SWIM IN THE PRESENCE OF LIFE GUARDS! THANK YOU. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...DRAG/IOVINO/NIERENBERG 1158P SHORT TERM...DRAG/IOVINO 1158P LONG TERM...KLINE AVIATION...DRAG/IOVINO/KLINE 1158P MARINE...DRAG/IOVINO/KLINE 1158P FIRE WEATHER... RIP CURRENTS...

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