Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 280139 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 939 PM EDT WED MAY 27 2015 .SYNOPSIS... HIGH PRESSURE REMAINS OFF THE COAST AND A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE REESTABLISHES ITSELF OFF THE EAST COAST FRIDAY INTO SATURDAY. A COLD FRONT IS FORECAST TO MOVE ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL RETURN TO THE NORTHEAST EARLY NEXT WEEK WHILE THE FRONT STALLS TO THE SOUTH. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A MOIST AIRMASS CONTINUES TO ADVECT INTO THE REGION UNDER A SOUTHERLY FLOW. THE EXCEPTION IS ALONG THE COAST WHERE THE DEW POINTS HAVE FALLEN SOME DUE TO THE MARINE INFLUENCE. THE LEVEL OF MOISTURE PRESENT COMBINED WITH SOME LEFTOVER BOUNDARIES SHOULD CONTINUE TO PRODUCE A FEW SHOWERS AND EVEN A THUNDERSTORM FOR AWHILE TONIGHT. THE BUOYANCY OF THE AIRMASS IS GOOD GIVEN THE MOISTURE, THEREFORE IT MAY JUST TAKE A LITTLE BIT OF LOW-LEVEL CONVERGENCE TO POP A SHOWER. THE INSTABILITY IS LESS THEREFORE MOST SHOULD BE MAINLY SHOWERS. AS A RESULT, WE MAINTAINED SOME LOW POPS FOR MANY AREAS FOR AWHILE. THE HOURLY GRIDS WERE ADJUSTED BASED ON THE LATEST OBSERVATIONS, AND THEN THE LAMP/LAV GUIDANCE WAS USED. WE SHOULD SEE PATCHY FOG DEVELOP ESPECIALLY WHERE MORE NOTABLE RAIN OCCURRED, HOWEVER WE HAVE LOWER CONFIDENCE ATTM WHETHER THIS WILL HAVE MUCH OF AN IMPACT AND THEREFORE IT WAS NOT ADDED ATTM. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... DURING THE DAYTIME THURSDAY, THE PREVIOUSLY MENTIONED SURFACE COLD FRONT IS EXPECTED TO APPROACH OUR FORECAST AREA DURING THE MORNING AND GRADUALLY CROSS THE REGION THROUGH THE AFTERNOON TO EVENING. SIMILAR TO WEDNESDAY, AN INCREASE IN INSTABILITY IS EXPECTED DURING THE DAY, AND WITH THE APPROACHING FRONT AND A SHORTWAVE ALOFT ACTING AS LIFTING MECHANISMS, MORE SCATTERED SHOWER/THUNDERSTORM ACTIVITY IS ANTICIPATED. WE BEGIN POPS A LITTLE EARLIER IN THE DAY, DURING THE MORNING, FOR OUR WESTERN ZONES. HIGHEST CHANCE POPS, THOUGH, ARE FOCUSED INTO THE AFTERNOON, BEFORE DECREASING THEN INTO THE EVENING AS THE FRONT PASSES BY TO THE EAST. MET/MAV GUIDANCE BLENDED WITH CONTINUITY YIELDS HIGH TEMPERATURES MOSTLY INTO THE MIDDLE AND UPPER 80S FOR THE REGION. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... A COLD FRONT WILL BE MOVING ACROSS THE AREA AT THE START OF THE PERIOD AND COULD HAVE SOME SHOWERS AND TSTMS WITH IT. THE PRECIP SHOULD BE WINDING DOWN EARLY IN THE PD. ON FRI, HIGH PRES BUILDS BACK INTO THE REGION, AND DRY CONDS ARE EXPECTED. LOW PRES THEN ADVANCES ACRS QUEBEC ON SAT AND ITS ASSOCD CDFNT WILL APPROACH FROM THE W ON SAT. THERE IS QUITE A BIT OF UNCERTAINTY AS TO PRECIP CHCS ON SAT. THE GFS IS FASTER WITH THE FRONT, AND HAS SOME PRECIP, MAINLY N. THE GFS IS SLOWER AND DRIER. FOR NOW WILL GO WITH LOW POPS. THE GFS HAS CFP SAT NIGHT, WITH THE ECMWF ON SUN. SHWRS/TSTMS WILL ACCOMPANY FROPA, BUT THERE STILL REMAIN QUESTIONS AS TO THE TIMING. THE FRONT THEN STALLS TO THE S OF THE REGION AS HIGH PRES BUILDS OVER QUEBEC. YESTERDAY, THE MDLS HAD DRIED OUT EARLY NEXT WEEK. NOW, THEY ARE MAKING IT WETTER. AGAIN, CONFIDENCE IS LOW AS THE MDLS TRY TO IRON THINGS OUT. LOWERED POPS A BIT YESTERDAY, AND RAISED THEM A BIT TODAY, BUT DON`T WANT TO MAKE ANY WHOLESALE CHANGES. ALSO, SOME QUESTIONS REMAIN AS TO AREAL EXTENT AND PLACEMENT OF THE PRECIP. BY TUE, THE LOW MOVE NEWD OUT TO SEA AND PRECIP CHCS EITHER MOVE NWD (GFS) OR DECREASE (ECMWF). THE FCST IS CONTINGENT ON THE STALLED FRONT AND WHERE IT STALLS, WHETHER IT WASHES OUT AND IF ANY WAVES DEVELOP UPON IT. THE MDLS ARE HAVING A DIFFICULT TIME RESOLVING THE FCST EARLY NEXT WEEK AND AS A RESULT, THE CONFIDENCE IN THIS FCST IS MUCH BELOW AVERAGE. THERE WILL LIKELY BE SOME PRECIP BEYOND SUN, BUT WHERE, WHEN, AND TO WHAT EXTENT REMAIN BIG QUESTIONS. TEMPS LOOK TO START ABV NRML BUT CUD BE BELOW NRML ERLY NEXT WEEK DEPENDING ON HOW THINGS PLAY OUT. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF TONIGHT...VFR THROUGH MUCH OF THE NIGHT. AN ISOLATED SHOWER OR THUNDERSTORM FOR AWHILE, HOWEVER THE COVERAGE IS RATHER SMALL TO INCLUDE IN THE TAF. SOME LOW CLOUDS ARE ANTICIPATED TO DEVELOP TOWARD MORNING, THEREFORE CONTINUED WITH A 1000-1500 FOOT CEILING. SOME FOG SHOULD DEVELOP, ALTHOUGH THIS MAY BE MORE LIKELY WHERE THE HEAVIEST RAIN OCCURRED. SOUTHERLY WINDS LESS THAN 10 KNOTS. THURSDAY...ANY LOW CLOUDS/FOG ARE EXPECTED TO LIFT BY MID MORNING, THEN VFR. WHILE SOME SHOWERS/THUNDERSTORMS SHOULD DEVELOP DURING THE DAY /WHICH MAY LOCALLY REDUCE CEILINGS AND VISIBILITIES/, THE TIMING AND COVERAGE OF THESE IS TOO LOW AT THIS TIME TO INCLUDE IN THE TAFS. SOUTHWESTERLY WINDS WILL GRADUALLY BECOME MORE WESTERLY AND INCREASE TO AROUND 10 KNOTS. OUTLOOK... THU NIGHT...GENERALLY VFR. SCT SHRA/TSRA EARLY. MDT CONFIDENCE. FRI...GENERALLY VFR. ISOLATED SHOWERS/THUNDERSTORMS POSSIBLE FOR WESTERN TAFS. FRI NIGHT...VFR EARLY, THEN LOWERING CIGS/VSBYS POSSIBLE OVERNIGHT. MDT CONFIDENCE. SAT...IFR/MVFR PSBL EARLY, THEN BECOMING VFR DURING THE DAY. SCATTERED SHRA/TSRA PSBL WHICH MAY REDUCE CIGS/VSBYS. GUSTY SOUTH- SOUTHWEST WINDS AROUND 20 KNOTS. LOW TO MDT CONFIDENCE ON TSRA. SAT NIGHT-SUN...SUB-VFR CONDITIONS POSSIBLE, ESPECIALLY WITH SHRA/TSRA. LOW TO MDT CONFIDENCE. && .MARINE... THROUGH TONIGHT, SOME WIND GUSTS TO AROUND 25 KNOTS ARE EXPECTED, ALONG WITH WAVE HEIGHTS IN THE 3 TO 5 FOOT RANGE FOR THE COASTAL WATERS. WE THEREFORE MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THROUGH 10Z THURSDAY. THEREAFTER, WHILE SOME WIND GUSTS TO AROUND 20 KNOTS MAY STILL OCCUR FOR THE COASTAL WATERS, MAINLY SUB-SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED FOR THE COASTAL WATERS AND FOR DELAWARE BAY THROUGH THURSDAY. OUTLOOK... THU-SAT...SUB-SCA CONDS EXPECTED, ALTHOUGH WINDS MAY GUST AROUND 20 KNOTS AT TIMES. SAT NIGHT...SEAS MAY RETURN TO 5 FEET OR GREATER OVERNIGHT AHEAD OF AN APPROACHING CDFNT. SUN...SCA CONDS LIKELY WITH CFP. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ450>455. && $$ SYNOPSIS...NIERENBERG NEAR TERM...GORSE SHORT TERM...KLINE LONG TERM...NIERENBERG AVIATION...GORSE/KLINE/NIERENBERG MARINE...KLINE/NIERENBERG

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