Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 221321

Area Forecast Discussion
National Weather Service Mount Holly NJ
921 AM EDT WED JUN 22 2016

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.


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.


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.


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!


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.


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


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.

Thu through Thu night...Mostly sub-sca conditions.  Tstms with
local higher winds and seas expected.

Fri thru Sun... No marine headlines anticipated.


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:/


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




Near Term...Drag/O`Hara
Short Term...Drag
Long Term...Nierenberg
Tides/Coastal Flooding...
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