Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 231910 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 310 PM EDT TUE AUG 23 2016 .SYNOPSIS... High pressure will shift offshore tomorrow. A cold front approaching from the northwest will arrive Friday. Another area of high pressure is anticipated to build east over New England, before shifting offshore on Monday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... High pressure centered over MD will slowly continue to drift to the east tonight. Heights and thicknesses will slowly rise during the overnight, resulting in slightly warmer temperatures compared to Monday night. Surface dewpoints will slowly creep up as well, rising into the upper 50s by daybreak. With clear skies, nearly calm winds, and increasing low level moisture, patchy fog is possible well after midnight tonight. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... Another tranquil day on tap for Wednesday as high pressure continues to drift off the Mid-Atlantic coast. With SW flow behind the departing high, temperatures and surface dewpoints will be a bit higher than today, with highs generally in the mid to upper 80s and surface dewpoints climbing to near 60. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Thursday through Friday...As the high slides further off shore, a cold front will approach our region from the Great Lakes. Kept a mention of slight chance of thunderstorms for Thursday night, as the front gets closer, but removed mention of precipitation on Friday. Even though the front will be crossing through the region on Friday, think this period will remain dry as the large upper level high over the southeastern U.S. will be building north through this time, resulting in synoptic scale subsidence for our region. Saturday and Sunday...Any post-frontal cooling trend will be tempered by the building upper level ridge centered over the southeastern U.S. Thus, have gone slightly above MOS guidance for highs, but still kept it below raw model highs (for both the GFS and ECMWF), until there is better run to run consistency on the position of the ridge axis. Monday and Tuesday...Next cold front is expected to approach our region through this period. Some question as to how far south it will get given the still persistent upper level ridge. Given the uncertainty, kept 20 to 30 percent PoPs throughout this period. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. VFR through the TAF period. Some patchy MVFR VSBY in BR possible, mainly at KRDG, late tonight through daybreak Wednesday. Winds generally out of the W at 5-7 KT through the afternoon. Sea breeze should keep winds out of the S at KACY 5-7 KT through this evening. LGT/VRB winds tonight, and then SW winds become 5-7 KT late Wednesday morning with afternoon sea breezes likely at favored terminals. Outlook... Thursday...VFR conditions expected. Thursday night...mostly VFR. MVFR conditions possible with isolated to scattered thunderstorms. Friday through Sunday...VFR conditions expected. && .MARINE... High pressure over the Delmarva will slowly drift offshore tonight through Wednesday. S-SW winds at 5-10 KT will become W by Wednesday morning before tuning S and increasing to 10-15 KT with occasional gusts to 20 KT in the late afternoon. Seas will generally average 1- 3 feet. Outlook... Thursday through Friday...southerly flow increases especially Thursday night with gusts above 20 kt expected. However, at this time, winds and seas are expected to stay just below SCA conditions. Winds will shift to northwesterly late in the day on Friday as a cold front moves through. Saturday through Sunday...winds and seas should remain below SCA criteria through this time. RIP CURRENTS... For today, the risk for the formation of dangerous rip currents looks to be low. For Wednesday, the probable risk for the formation of dangerous rip currents is low. However this may increase to moderate, especially for the New Jersey beaches, especially if the wind turns more southeasterly as it increases some in the afternoon. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Johnson Near Term...MPS Short Term...MPS Long Term...Johnson Aviation...Johnson/MPS Marine...Johnson/MPS is the U.S. government's official web portal to all federal, state and local government web resources and services.