Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 210841 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 441 AM EDT SUN SEP 21 2014 .SYNOPSIS... LOW PRESSURE OFF THE CAROLINA COAST WILL MOVE NORTHEAST OFF THE MID-ATLANTIC COAST TODAY WHILE A COLD FRONT APPROACHES FROM THE WEST. THE FRONT IS EXPECTED TO MOVE THROUGH THE MID-ATLANTIC STATES TONIGHT. HIGH PRESSURE BUILDING IN FROM THE MIDWEST EARLY IN THE WEEK WILL PERSIST OVER THE AREA THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TWO FEATURES WILL INFLUENCE TODAYS WEATHER ACROSS OUR AREA. THE FIRST IS THE COASTAL LOW OFF OF THE CAROLINAS MOVING UP THE EASTERN SEABOARD TODAY. THIS LOW CONTINUES TO LOOK LIKE IT WILL REMAIN OFFSHORE. HOWEVER, IT IS SENDING SOME SHOWERS UP OUR WAY, MAINLY ALONG THE COASTAL AREAS. THERE ARE SOME ISOLATED THUNDERSTORMS EMBEDDED IN THESE SHOWERS SO WE HAVE ADDED THEM INTO THE FORECAST THROUGH THIS MORNING RIGHT ALONG THE COAST AND OVER THE WATER. THIS LOW SHOULD BE OFF OF OUR COASTAL WATERS BY THIS AFTERNOON AND THEN WILL QUICKLY MOVE TO THE NORTHEAST. THE SECOND FEATURE IS A LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT LAKES. THIS LOW WILL DRAG A COLD FRONT TOWARDS OUR AREA. HOWEVER, THIS FEATURE IS A LITTLE SLOWER MOVING AND THE FRONT WILL NOT REACH OUR WESTERN AREAS UNTIL THIS AFTERNOON/EARLY EVENING. SOME SHOWERS WILL DEVELOP AHEAD OF THE MAIN FRONT AND THUNDER, IF IT OCCURS, WOULD BE PRETTY ISOLATED AS CONVECTIVE PARAMETERS DO NOT LOOK ALL THAT ROBUST TODAY. BEST CHANCES FOR THUNDER WOULD BE TOWARD THIS AFTERNOON. TODAY WILL START OFF PRETTY CLOUDY, ESPECIALLY THE FURTHER EAST AND TOWARDS THE COAST YOU GO. IN ADDITION TO THE CLOUDS, SOME FOG WILL EXIST AND WITH THE LOWER SUN ANGLE (THINK MORE OF A MARCH SUN ANGLE) THIS TIME OF YEAR, IT WILL TAKE A BIT LONGER BEFORE WE REALLY START TO CLEAR OUT. WE DO EXPECT THAT BY LATE MORNING/EARLY AFTERNOON, THE SUN SHOULD START TO MAKE AN APPEARANCE AND WE WILL CERTAINLY SEE SURFACE TEMPERATURES RESPOND. WITH THE WARMER OVERNIGHT TEMPERATURES, WE HAVE A PRETTY GOOD STARTING POINT TO SEE TEMPS RISE TODAY. EXPECT HIGHS TO REACH INTO THE UPPER 70S TO LOWER 80S ACROSS THE REGION AS WE HAVE A MORE SOUTHWESTERLY FLOW DEVELOPING THROUGH THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE COLD FRONT WILL BE THE FEATURE IMPACTING OUR AREA TONIGHT. THE FRONT WILL MOVE INTO THE AREA THIS EVENING AND THEN SLOWLY PUSH ITS WAY THROUGH, MAKING ITS WAY OFFSHORE BY LATE TONIGHT OR EARLY MONDAY. THE FRONT WILL HAVE SOME SHOWERS ASSOCIATED WITH IT AND MAYBE A FEW RUMBLES OF THUNDER, ALTHOUGH INSTABILITY DOES NOT LOOK AT ALL IMPRESSIVE. WITH THE SUN SETTING EARLIER AT THIS TIME OF YEAR, WE WILL LOSE SOME OF THE OOMPH NEEDED TO HELP PRODUCE THUNDERSTORMS. THE FRONT MOVES OFFSHORE LATE TONIGHT AND WE WILL SEE A WIND SHIFT TO THE NORTHWEST OCCUR. COOLER AIR WILL START TO MOVE IN TOWARD MORNING BUT WILL NOT ARRIVE IN TIME TO IMPACT OVERNIGHT TEMPS. EXPECT LOWS TO BE IN THE 50S TO LOWER 60S ACROSS THE REGION. && .LONG TERM /MONDAY THROUGH SATURDAY/... RATHER BENIGN WEATHER IS EXPECTED THROUGH THE ENTIRE EXTENDED FORECAST PERIOD OF MONDAY THRU SATURDAY. THE COLD FRONT FORECAST TO MOVE ACROSS THE AREA TONIGHT SHOULD BE OFF THE MID-ATLANTIC COAST BY MONDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST BEHIND THE FRONT ON MON AND TUE IS EXPECTED TO STRENGTHEN OVER NEW ENGLAND BY WED AND THU...AND THEN SHIFT SLIGHTLY WEST TO THE LOWER GRTLKS AND MID-ATLANTIC BY FRI/SAT. MEANWHILE AN UPPER TROF OVER THE ERN US ON MONDAY WILL GIVE WAY TO AN UPPER RIDGE BUILDING OVER THE REGION BY MID WEEK AND CONTINUING INTO NEXT WEEKEND. THE 12Z ECMWF SHOWED AN UPPER LOW DEVELOPING OVER THE MID-ATLANTIC BY THE LATTER PART OF THE WEEK. HWVR THIS SOLN SEEMS TO BE OUT OF LINE WITH OTHER MODELS INCLUDING THE EURO ENSEMBLE...ACCORDING TO WPC...AND NOW THE NEW 00Z ECMWF SHOWS MORE OF A WEAKNESS IN THE UPPER RIDGE RATHER THAN A CLOSED LOW. STILL...WITH EASTERLY/ONSHORE FLOW AROUND THE NEW ENGLAND HIGH PRES...HAVE ACCEPTED WPC POPS OVER DELMARVA AND SRN NJ FOR THU AND THU NIGHT...BUT WITH A SMALL DOWNWARD ADJUSTMENT. LOW-LEVEL COLD ADVECTION WILL BE IN PLACE FOR MON AND TUE BUT SHOULD BECOME NEUTRAL BY MID-WEEK...WITH A WARMING TREND BY WEEKS END. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...MVFR/IFR CONDITIONS WILL CONTINUE THROUGH LATE THIS MORNING. SKIES SHOULD START TO CLEAR OUT AND CONDITIONS WILL IMPROVE TO VFR BETWEEN 14-16Z ACROSS THE TERMINALS. WINDS WILL BE OUT OF THE SOUTHWEST AROUND 10 KNOTS OR LESS. A MORE EASTERLY FLOW IS LIKELY ALONG THE COAST AND AT KACY THROUGH EARLY THIS AFTERNOON. SOME SHOWERS ASSOCIATED WITH A COASTAL LOW PRESSURE SYSTEM CONTINUE TO MOVE NORTHWARD ALONG THE COAST. IT LOOKS LIKE THESE SHOWERS WILL REMAIN MOSTLY OFFSHORE BUT MAY BRIEFLY IMPACT KACY THROUGH THIS MORNING. TONIGHT...A COLD FRONT WILL CROSS THE REGION TONIGHT. WINDS WILL SHIFT FROM THE SOUTHWEST TO THE NORTHWEST BEHIND THE FRONTAL PASSAGE. THERE IS A CHANCE FOR SOME SCATTERED SHOWERS AHEAD OF AND ALONG THE COLD FRONT. BEST CHANCES ARE LATER THIS AFTERNOON THROUGH THIS EVENING. OUTLOOK... MONDAY...NW WIND GUSTS AROUND 20 KT ARE POSSIBLE MONDAY IN ASSOCIATION WITH HIGH PRESSURE BUILDING IN BEHIND A COLD FRONT. SOME STRATO-CU MAY DEVELOP IN THIS SETUP, WHICH COULD MAY RESULT IN A PERIOD MVFR CIGS, MOST LIKELY FOR RDG/ABE TERMINALS. MONDAY NIGHT THROUGH THURSDAY...VFR AND LIGHT WINDS EXPECTED. && .MARINE... SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH NOON TODAY FOR OUR OCEAN FRONT. SEAS WILL START TO SUBSIDE THIS AFTERNOON BEFORE STARTING TO RAMP UP AGAIN AS LOW PRESSURE PASSES TO THE EAST OF OUR AREA WATERS. THERE LOOKS TO BE A PERIOD OF SUB-ADVISORY CONDITIONS AND THROUGH THIS AFTERNOON INTO THIS EVENING. WILL HOLD OFF ON EXTENDING THE SMALL CRAFT ADVISORY AT THIS TIME. SHOWERS WITH EMBEDDED THUNDERSTORMS, ASSOCIATED WITH THE LOW PRESSURE SYSTEM TO OUR SOUTH, WILL CONTINUE TO MOVE THROUGH THE WATERS THIS MORNING. EXPECT THEM TO GRADUALLY MOVE NORTH AND EAST AS THE LOW MAKES ITS WAY UP THE MIDDLE ATLANTIC COAST. OUTLOOK... MONDAY AND MONDAY NIGHT...A COLD FRONT WILL MOVE THRU THE WATERS EARLY MONDAY MORNING RESULTING IN A WIND SHIFT FROM SW TO NW. POST- FRONTAL NW WINDS OF 15-20 KT GENERALLY EXPECTED BUT CANNOT RULE OUT LOCALLY STRONGER GUSTS ON MONDAY INTO MONDAY NIGHT. WITH THE NW FLOW SEAS COULD BUILD UP TO 5 FEET WELL OFFSHORE. HOWEVER THIS IS NOT CERTAIN AND WITH SCA CURRENTLY IN EFFECT AND A LULL EXPECTED THIS AFTN/EVE...WILL NOT ISSUE ANOTHER SCA AT THIS TIME. TUESDAY THROUGH THURSDAY...SUB-SCA CONDITIONS EXPECTED FOR TUE AND WED BUT INCREASING EAST FLOW BY THU COULD BUILD SEAS TO NEAR 5 FEET... ESPECIALLY CAPE MAY AND SOUTH. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ450>455. && $$ SYNOPSIS...AMC NEAR TERM...MEOLA SHORT TERM...MEOLA LONG TERM...AMC AVIATION...AMC/MEOLA MARINE...AMC/MEOLA

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.