Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 221321 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 921 AM EDT WED JUN 22 2016 .SYNOPSIS... Weak high pressure will remain over the area through tonight. Then, low pressure over the midwest will move east and off the Mid Altantic coast by Thursday night. High pressure will then build in for the remainder of the week into early next week. A cold front will approach from the west next Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Clouds have rapidly decreased across most of the region except for some areas in Mercer, Ocean and Atlantic counties. Clouds across these areas will be gone shortly. Mostly sunny into the afternoon most areas, some diurnal cu especially nrn third of the area. Northwest winds gust to 20-25 mph midday and afternoon. PWAT for comparison purposes upcoming to Thursday and yesterday, down to 0.8-0.9 inches. Forecast elements were derived from a 50 50 blend of the 00z/22 gfs/nam mos guidance checked against the 00z/22 ecmwf.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... Clear or Mostly clear to start with radiational cooling, especially countryside near and north of I-78 where upper 40s may occur by 08z/23. For now fcstg 50s there, since thick cloud may be arriving around 3-4 am there. Elsewhere rapidly increasing mid and high clouds between 11pm and 3am, south of I-78. Showers develop shortly after the mid deck arrives, around sunrise southeastern sections of Pa and Md upper eastern shore through De and the s third of NJ in waa. Isolated tstms possible mainly de and MD eastern shore after 4 am. PWAT increases to nearly 2 inches Delmarva by 12z Thursday and 1.5 inches near I-80. Forecast elements were derived from a 50 50 blend of the 00z/22 gfs/nam mos guidance checked against the 00z/22 ecmwf and the 00z/22 NSSL WRF which looks good for its qpf onset. The 00z/22 SPC WRF looks like something went wrong. it has virtually nothing here late tonight. && .LONG TERM /THURSDAY THROUGH TUESDAY/... The most active part of the extendd pd will be the beginning, when an area of low pres moves acrs the area on Thu. This low, movg from the midwest erly, acrs the Mid-Atlc and off the cst by later Thu will bring a chc of shwrs and tstms. The SPC outlook continues to have most of cntrl and srn NJ, sern PA and all of the Delmarva in a slgt risk for svr tstms. As the low moves ewd, warm and moist air will be located s of the low and latest guid seems to have moved the low and its assocd wm fnt a bit swd. The biggest threat still appears to be strong wind. CAPE is marginal at best, but there is unidirectional shear and at least some uvv. By Thu night, the precip will be ending as high pres builds in from the n. This high will then be the dominant wx feature for the remainder of the week into the weekend. THe high will move over the Mid-Atlc by Sat into Sun then off the coast by Mon. As it does, low pres will move into ern Canada. The cdfnt assocd with this low will approach from the w on Mon. However, the ltst guid has slowed the front down. It will be close to our wrn counties Mon eve, but will not cross the area until Tue during the day. That will be our next chc of rain. With a fairly progressive patn, and a longwave h5 trof in some form temps will be close to nrml thru the pd. Dew points in the 50s in late June are always welcome! && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Clouds across KMIV,KACY and KTTN will mix out by 10 am, then VFR scattered clouds aoa 7000 ft. Winds become northwest and gust 20-23 kt everywhere 14z-21z. Tonight...VFR with cigs developing aoa 5000 ft after 06z/23. Mid level warm air advection showers should develop by 10z/23 vicinity PHL- KILG westward. Outlook... Thu...Shra/tsra will bring lower cigs/vsbys thru the period, especially over srn areas. High confidence. Thu night...any lingering shra/tsra ending erly, mainly s. otherwise vfr. High confidence. Fri thru Sun...VFR conditions expected under high pressure. High confidence.
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&& .MARINE...
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Small craft advisory for hazardous seas dropped with the morning CWF. Seas trending steady to down through the day. Winds gusts may approach SCA later, confid in this is low with very warm air and cool seas conditions. RIP CURRENTS: Issued a moderate risk today. just too much swell and its been causing problems along our shore the past 4 days. Outlook... Thu through Thu night...Mostly sub-sca conditions. Tstms with local higher winds and seas expected. Fri thru Sun... No marine headlines anticipated.
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&& .TIDES/COASTAL FLOODING... Yesterdays multiple 70 kt northwest wind gusts at the entrance to De Bay resulted in unusual sharp 1 ft oscillations in the tide levels during the low tide, roughly between 1930z and 20z/21 from Cape May NJ to Lewes DE. There may have been some residual very minor fluctuations into the subsequent high tide. This can all be seen on the NOS tide gage data http:/tidesandcurrents.noaa.gov/stations && .CLIMATE... Brandywine Shoal Light DE - an NOS instrumented tide and met data site, recorded its strongest wind gust during its short interrupted period of record dating back to June 21, 2002 (Sandy knocking out this station and so interrupted the period of record for a year). Still that Sandy knockout wind was not as strong as what occurred yesterday. Brandywine Shoal recorded a peak gust of 74 kt (85 mph) at 330 pm. In case, the midwest system holds together and models return to a high impact 6 hour torrential downpour ..these are the records closest to the expected axis of tomorrows event. GED 1.03 1991 POR back to 1948 && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...None. NJ...None. DE...None. MD...None. MARINE...None.
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&& $$ Synopsis...Nierenberg Near Term...Drag/O`Hara Short Term...Drag Long Term...Nierenberg Aviation...Drag/Nierenberg/O`Hara Marine...Drag/Nierenberg/O`Hara Tides/Coastal Flooding... Climate...

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