Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 190451 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1251 AM EDT Wed Jul 19 2017 .SYNOPSIS... A weak front will dissipate across the area tonight. It will be followed by weak high pressure which will settle across the area Wednesday and remain through Thursday. Another front will affect the area later Friday into Friday night. The front will not move far from the area and continue to bring unsettled conditions for the upcoming weekend and into early next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Frontal boundary continues to dissipate over the region. Most of the convection has ended, but there are a few diminishing thunderstorms west of Chester County. Those should end before making it into SW portions of the forecast area. Otherwise, warm and muggy tonight with abundant low level moisture. While some low clouds and patchy fog may develop toward daybreak, it should not be as widespread as it was Tuesday morning being that we will be more squarely in the tropical type air mass. Overnight temperatures are anticipated to be mainly in the mid to upper 60s and the lower 70s. Winds should stay light and variable. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... A fair amount of sunshine is expected for Wednesday along with a southwest wind around 5 to 10 MPH. Conditions will remain very warm and humid. Maximum temperatures are forecast to be in the lower 90s at most locations, with readings not getting above the 80s in the elevated terrain and along the immediate coast. Maximum heat index values are expected to be generally in the upper 90s, which is below the Heat Advisory criteria. The guidance is suggesting that an instability maximum may develop over or near the Philadelphia metropolitan area on Wednesday afternoon. Mixed layer CAPE values could rise into the 1000 to 1500 J/kg range. As a result, we will keep a low or slight chance of showers and thunderstorms for that time period. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A pattern which favors above normal temperatures and occasional showers is in the long term part of the forecast. Temperatures will continue to be above normal Thursday through next Monday in many areas. The heat will not be excessive however although heat indicies may approach advisory levels at times. High temperatures will be mostly in the low or mid 90s through Sunday and then a few degrees less for next Monday. After that, temperatures should slip back to a little below normal for Tuesday. Precipitation will be typical for summer with mostly dry days and chances for scattered showers and tstms. Thursday and Friday will likely be the two days with the lowest chances for precipitation. A front may bring some showers Friday night however. The front will stall across the area, so the period Saturday through next Monday will have almost daily chcs for showers and thunder. The favored times are afternoon and evening. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Patchy fog/stratus may briefly lower conditions to MVFR/IFR in the pre-dawn hours, and then that fog/stratus burns off between 12-13Z. Predominantly VFR thereafter. Isolated to scattered SHRA/TSRA possible again this afternoon. Best chances will be from KTTN-KPNE-KPHL-KILG, but confidence of a storm developing over any given terminal is low, so will not mention in 06Z TAF package. Generally VFR conditions continue late tonight into Thursday morning. Patchy fog possible, but less so compared to early this morning. LGT/VRB to calm winds through mid-morning, then W-SW winds 5-10 KT. Winds become nearly calm after 00Z Thursday. OUTLOOK... Wed night thru Fri...VFR conditions expected. A little early morning haze or fog possible in rural areas. Fri night thru Sunday...Mostly VFR, but sct showers and tstms could bring lower cigs/vsbys at times. Favored times are afternoon and early evening. Patchy pre-dawn fog psbl too.
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&& .MARINE... High pressure over the Atlantic will continue to influence the coastal waters of Delaware and New Jersey for tonight and Wednesday. The wind should favor the south and southwest at less than 15 knots. Wave heights on our ocean waters will remain around 2 feet and waves on Delaware Bay should be 2 feet or less. OUTLOOK... Generally sub-SCA conditions expected through the period. Sct showers and tstms are possible mostly between Fri night and Sunday night. Locally higher winds and seas in tstms. RIP CURRENTS... We will keep the moderate risk for the development of dangerous rip currents along the New Jersey coast into this evening. There is a low risk at the Delaware beaches. We are anticipating a low risk for both New Jersey and Delaware on Wednesday. However, an underlying 10 to 12 second southeasterly swell may reach the coast on Wednesday afternoon possibly resulting in a developing moderate risk at that time. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...O`Hara Near Term...MPS Short Term...Iovino Long Term...O`Hara Aviation...MPS Marine...Iovino/MPS/O`Hara

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