Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 270444 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1244 AM EDT FRI MAR 27 2015 .SYNOPSIS... A STRONG COLD FRONT SWEPT THROUGH THE REGION ON THURSDAY EVENING. LOW PRESSURE WILL FORM ALONG THIS FRONT EAST OF THE MID ATLANTIC COAST FRIDAY AFTERNOON AND HEAD NORTHEAST OUT TO SEA LATE SATURDAY. STRONG CANADIAN HIGH PRESSURE IS EXPECTED TO MOVE THROUGH THE REGION ON SUNDAY INTO MONDAY BEFORE ANOTHER COLD FRONT PASSAGE LATER ON MONDAY. ANOTHER SHOT OF HIGH PRESSURE FOR TUESDAY AND WEDNESDAY IS EXPECTED AHEAD OF THE NEXT COMPLEX LOW PRESSURE SYSTEM ON THURSDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE COLD FRONT WAS THROUGH OUR ENTIRE FORECAST AREA AT 1230 AM. THE BOUNDARY HAD JUST PASSED FENWICK ISLAND, DELAWARE. AN AREA OF SHOWERS IN THE WAKE OF THE FRONT EXTENDED FROM NORTHEASTERN MARYLAND AND CENTRAL AND NORTHERN DELAWARE NORTHEASTWARD INTO THE PHILADELPHIA METROPOLITAN AREA, AS WELL AS SOUTHERN, CENTRAL AND NORTHEASTERN NEW JERSEY. THE SHOWERS WERE MOVING NORTHEASTWARD. A NARROW BAND OF RAIN SHOWERS EXTENDED FROM THE LOWER SUSQUEHANNA RIVER VALLEY, ACROSS THE LEHIGH VALLEY AND THE POCONOS TO THE CATSKILLS. ANOTHER AREA OF SHOWERS LOCATED OVER VIRGINIA WILL BUILD UP INTO OUR REGION OVERNIGHT. COLD ADVECTION WILL CONTINUE DURING THE NIGHT AND THE PRECIPITATION WILL LIKELY CHANGE TO SNOW AND PERHAPS SOME ICE IN PARTS OF BERKS COUNTY, THE LEHIGH VALLEY, THE POCONOS AND NORTHERN NEW JERSEY. SNOW AND ICE TOTALS SHOULD BE LIMITED. HOWEVER, THERE COULD BE ENOUGH OF AN ACCUMULATION IN SPOTS TO CREATE SLIPPERY CONDITIONS. SOME LOCATIONS MAY RECEIVE UP TO A HALF INCH OF SNOW OR PERHAPS A TRACE AMOUNT OF ICE. UP TO AN INCH OF SNOW COULD ACCUMULATE IN THE ELEVATED TERRAIN. TEMPERATURES RANGED FROM THE UPPER 30S IN THE POCONOS TO AROUND 60 IN SOUTHERN DELAWARE AT 1230 AM. READINGS SHOULD DROP INTO THE 30S IN OUR NORTHERN AND CENTRAL COUNTIES AND INTO THE LOWER 40S IN THE SOUTH BY DAYBREAK. THE WIND WILL REMAIN OUT OF THE NORTHWEST AROUND 10 MPH. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/... THE COLD FRONT MAKES ITS WAY FARTHER OFF THE COAST FRIDAY WITH SOME LINGERING RAIN HANGING AROUND - PROBABLY MIXED WITH ICE PELLETS OR WET SNOW AT DAYBREAK VCNTY I-95 NWWD IF PCPN IS ON- GOING AT THAT TIME, WHICH AM EXPECTING. PCPN ENDING FROM NW TO SE DURING THE AFTN AS A WAVE OF LOW PRESSURE FORMS OFFSHORE EAST OF THE VA CAPES. TEMPERATURES WILL BE MUCH COOLER ON FRIDAY IN MANY AREAS COMPARED TO TODAYS MAX TEMPS. HIGHS WILL BE IN THE 40S TO NEAR 50 ACROSS THE REGION ON FRIDAY WITH PLENTY OF CLOUD COVER AROUND. NORTHWEST WINDS MAY BE GUSTY EARLY BUT SHOULD RELAX AS THE FRONT MOVES OFFSHORE. && .LONG TERM /SATURDAY THROUGH FRIDAY/... 5-WAVE MODEL GUIDANCE SHOWS BROAD TROUGHING IN THE EAST WITH BROAD RIDGING ACROSS THE WESTERN STATES THROUGH MOST OF THE LONG TERM PERIOD. THE PATTERN ALOFT HAS A FAST FLOW LOOK WITHOUT MUCH BLOCKING WHICH ADDS TO A BIT OF THE UNCERTAINTY/TIMING OF EMBEDDED SHORTWAVES WITHIN THE MID-LEVEL FLOW. TOWARDS THE END OF THE PERIOD A NEARLY ZONAL FLOW LOOKS TO TAKE SHAPE. FRIDAY NIGHT - SATURDAY...DEEP ANOMALOUS MID-LEVEL TROUGH WILL BE OVERHEAD AS STRONGER NORTHERN STREAM ENERGY TRIES TO PHASE WITH WEAKER, SLOWER MOVING, SOUTHERN STREAM ENERGY. EVEN WITH MINIMAL PHASING SURFACE CYCLOGENESIS LOOKS TO OCCUR TO THE SOUTH OF OUR REGION LATE ON FRIDAY. THIS WEAK INFLECTION WILL MOVE ALONG THE AFOREMENTIONED COLD FRONT SITTING OFFSHORE ON SATURDAY AND COULD THROW SOME LIGHT PRECIPITATION BACK ACROSS THE REGION DURING THE DAY. THINKING THAT A MAJORITY OF THE LIFT AND MOISTURE WITH THIS SYSTEM WILL REMAIN TO OUR NORTHEAST, OVER NEW ENGLAND, AND FARTHER OFFSHORE. THE PASSAGE OF THE MID-LEVEL LOW COULD ALSO SPARK A FEW INSTABILITY SHOWERS DURING THE AFTERNOON. THERMALLY WE WILL BE DROPPING BELOW FREEZING THROUGHOUT THE COLUMN BY SATURDAY AFTERNOON SO MOST OF THE PRECIPITATION SHOULD FALL AS SNOW. TRYING TO COMBAT ANY DAYTIME HEATING, EVEN WITH A MULTITUDE OF CLOUDS AND NORTHERLY WINDS, WILL BE TOUGH WITH BOUNDARY LAYER TEMPERATURES EXPECTED TO BE IN THE MID TO UPPER-30S...THE ONE CAVEAT WOULD BE STRONGER DYNAMIC COOLING WITH THE PLACEMENT OF AN INVERTED TROUGH/MESOSCALE BANDING FEATURE...THOUGH IT IS ILL-DEFINED ACROSS OUR AREA AT THIS TIME. SUNDAY...RIDGING TO OUR SOUTH RE-ESTABLISHES IT SELF ACROSS THE REGION FOR THE SECOND HALF OF THE WEEKEND. THIS WILL PROVIDE MOSTLY CONDITIONS ACROSS THE REGION AS TEMPERATURES REMAIN WELL BELOW NORMAL. MONDAY...RIDGING SLIDES OFF THE SOUTHEAST COAST AND A RETURN FLOW WITH LOW-LEVEL WARM AIR ADVECTION KICKS IN. TEMPERATURES MAY BE ABLE TO WARM TO ABOVE NORMAL, AS WE CONTINUE THE TUMULTUOUS EARLY SEASON TEMPERATURE SWINGS. THERE DOES NOT APPEAR TO BE A GREAT DEAL IN MOISTURE SURGE WITH THIS NEXT SYSTEM, AS IT APPROACHES FROM THE WEST. WITH THE LACK OF MOISTURE WE KEEP THE SLIGHT CHANCE POPS IN THE FORECAST, THOUGH THE BETTER LIFT WILL ACCOMPANY THE ADVANCING COLD FRONT LATER MONDAY AFTERNOON SO POPS MAY BE INCREASED IN TIME. TUESDAY - THURSDAY...THE FLOW ALOFT, AS MENTIONED ABOVE, REMAINS QUICK AND ACTIVE. NUMEROUS EMBEDDED WAVES OF ENERGY SLIDE THROUGH THE REGION DURING THIS TIME FRAME, EACH CARRYING THE CHANCE FOR SHOWERY ACTIVITY. THE BETTER CHANCES FOR SHOWERS WILL BE WEDNESDAY INTO THURSDAY AS ANOTHER SYSTEM PUSHES IN FROM THE WEST. ANOTHER LOW- LEVEL MOISTURE SURGE IS EXPECTED WITH THIS SYSTEM AS TEMPERATURES LOOK TO REMAIN AT OR SLIGHTLY ABOVE AVERAGE FOR THE FIRST COUPLE DAYS OF APRIL...THIS COULD EASILY CHANGE WITH TIME. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY, AND SURROUNDING AREAS. CONDITIONS WILL VARY BETWEEN VFR AND MVFR AS RAIN SHOWERS CONTINUE TO LIFT NORTHEASTWARD THROUGH OUR REGION DURING THE NIGHT. THE RAIN MAY CHANGE TO SNOW AROUND KRDG AND KABE AFTER ABOUT 0800Z WITH LITTLE ACCUMULATION ANTICIPATED. DRYING WILL TAKE PLACE ON FRIDAY WITH AN IMPROVEMENT MAINLY INTO THE VFR CATEGORY ALONG WITH A DIMINISHING CHANCE FOR PRECIPITATION. A NORTHWEST WIND AROUND 10 KNOTS OVERNIGHT AND ON FRIDAY MAY GUSTS NEAR 20 KNOTS AT TIMES DURING THE DAYLIGHT HOURS. OUTLOOK... FRIDAY NIGHT - SATURDAY...MVFR OR LOWER POSSIBLE IN RAIN/SNOW SHOWERS. NORTHERLY WINDS. SUNDAY - MONDAY...VFR. NORTHERLY WINDS VEER TOWARDS THE SOUTHWEST AND BEGIN TO GUST MONDAY AFTERNOON. TUESDAY...VFR. WINDS VEER TOWARDS THE WEST-NORTHWEST...GUSTS EXPECTED. && .MARINE... A SMALL CRAFT ADVISORY REMAINS IN EFFECT ACROSS THE AREA WATERS, ENDING ON THE DELAWARE BAY AT 12Z FRIDAY AND ON THE OCEAN FRONT AT 22Z FRIDAY. WINDS SHIFTED TO NW WITH THE COLD FRONTAL PASSAGE. WINDS WILL GUST BEHIND THE FRONTAL PASSAGE BUT SHOULD DIMINISH THROUGH THE DAY. SEAS ARE RUNNING AROUND 6 TO 8 FEET ON THE OCEAN AND WILL REMAIN ELEVATED THROUGH FRIDAY. WAVES ON THE BAY ARE GENERALLY AROUND 2 TO 4 FEET. OUTLOOK... FRIDAY NIGHT - SATURDAY...SEAS WILL SUBSIDE LATE FRIDAY EVENING BUT COULD INCREASE A TAD SATURDAY WITH A NORTHERLY SURFACE FLOW DEVELOPING. COULD SEE SCA SEAS SATURDAY AFTERNOON. SUNDAY - TUESDAY...POSSIBLE SCA CONDITIONS SUNDAY THROUGH TUESDAY. WINDS VEER TOWARDS THE WEST AND THEN SOUTHWEST BY MONDAY AS HIGH PRESSURE SLIDES OFFSHORE. A COLD FRONT SLIDES THROUGH ON MONDAY EVENING AND WINDS MAY STAY ABOVE SCA THROUGH TUESDAY NIGHT. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ430- 431. && $$ SYNOPSIS...DRAG/HEFNERNEAR TERM...IOVINO SHORT TERM...DRAG/MEOLA LONG TERM...HEFNER AVIATION...HEFNER/IOVINO MARINE...DRAG/HEFNER/MEOLA

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