Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 131456
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1056 AM EDT Wed Sep 13 2017

.SYNOPSIS...
Pieces of the remnants of Irma will drift across the Mid Atlantic
states through through Friday. High pressure will briefly build
across the northeast Saturday, before weakening on Sunday and
retreating northward through Monday. Tropical cyclone Jose will
be monitored for its probable northward progress off the East
Coast later in the weekend into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
1024 AM ESTF: further updates regarding a band of showers
producing measurable rain. .04 KILG, .12 West Cape May with .27
at Rehoboth DE. Most stations in DE have measured this morning.

Small adjustments in temps/skycover and raised pops.

So a band of showers asstd with a portion of IRMAS PWAT increase
is here. The more direct-IRMA trough associated showers should
wait until tomorrow and Friday.

An isolated tstm cant be ruled out. We have seen some lightning
in Chester and Lebanon counties this morning.

Stratus to follow from south to north later today and tonight
and possibly a period of drizzle. Patchy fog is expected but
we`re not sure if it will clear aloft and so predicting it to be
dense fog is not confidently stated attm.

The 330 PM forecast will probably be a 50 50 blend of the
12z/13 GFS/NAM MOS.



&&

.SHORT TERM /THURSDAY/...
Irmas leftover trough should develop a period of widespread
showers.

This portion of the forecast at 330 PM will be a 50 50 blend of
the 12z/13 GFS/NAM MOS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
What`s left over of the remnants of Irma will finally drift
across the northeast later this week as the mid level
circulation will move across the area Thursday through Friday. A
weak surface trough is forecast to drift into the Mid Atlantic
on Thursday, before an area of low pressure develops later
Thursday then moves offshore Friday. The surface trough on
Thursday, combined with several short wave/vorticity impulses
associated with the mid level circulation will combine to create
enhanced lift across the area. This is expected to lead to a
period of showers Thursday into Thursday evening. Scattered
showers may continue Thursday night through Friday as the mid
level low begins to flatten some and lift to our northeast.

There is a chance for patchy fog to develop Thursday
night/Friday morning as well as Friday night/Saturday morning
for portions of the area as lower levels become saturated as an
inversion takes place over night.

On Saturday, high pressure is forecast to build across the
northeast, before weakening on Sunday and retreating northward
through Monday. There is a chance for isolated showers to
develop across the area over the weekend, especially Saturday as
the mid level trough and associated vorticity finally pulls
away.

Please stay tuned to the National Hurricane Center for the
latest official track and forecast regarding Hurricane Jose. If
you hear a rumor, especially on social media, regarding what
Jose may or may not do, please refer back to your National
Weather Service local office or the National Hurricane Center.
The official forecast goes out 5 days due to the considerable
uncertainty beyond Day 5. Regardless of Jose, we are at the peak
of hurricane season for the Atlantic Basin, so it is important
to have a hurricane plan in place. For tips as to what to have
in your hurricane plan, please check
http:/www.nws.noaa.gov/om/hurricane/plan.shtml

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through this afternoon...VFR but conditions lowering to 500-1500
feet from south to north this afternoon and vsby probably dropping
down to 2-4 mi in fog by 22z. A nw-se band of showers fm vcnty
KRDG-KILG-KWWD moves newd this aftn. An isolated tstm cannot be
ruled out.

Tonight...Probably IFR st/fog. Areas of LIFR in dense fog
possible, especially vcnty KTTN/KABE/KRDG. light south wind.

Thursday...IFR st/fog may persist through 15z vcnty KABE/KRDG
otherwise conditions improving to VFR cigs, but lowering to MVFR
conditions in a band or two of showers. light south to southwest
wind.


OUTLOOK...
Thursday night-Friday night...Periods of sub VFR conditions
likely with showers possible, especially Thursday. Chance of
fog/stratus Thursday night/Friday morning as well as Friday
night/Saturday morning.

Saturday-Sunday...Generally VFR. Patchy fog/stratus early
Saturday morning.

&&

.MARINE...
Long-period (10-14 sec) southeasterly swells from Hurricane
Jose continue through Thursday. Both Wavewatch and NWPS guidance
predict seas to be around 5 ft at 44009 and 44025 today, however
these models have had a definitive high bias for swell height
by about a foot. Accordingly, 3-4 ft seas should continue for
the coastal waters. Winds will not be an issue although
southerly winds will peak between 10-15 kt just off the NJ coast
late in the day.

OUTLOOK...
Thursday night-Friday night...Generally sub Small Craft
Advisory conditions expected. Seas forecast to be 3-4 feet.

Saturday-Sunday...Conditions may reach Small Craft Advisory
levels as seas may build to 5 feet.

Rip Currents...
The swell period is expected to decrease slightly over the
course of the day from about 13-14 seconds to about 11-12
seconds. The waves in the surf zone however should remain low
enough, despite the combination of the long period swells and
south winds increasing to 10-15 mph this afternoon, to keep the
rip current risk at moderate.

A long duration of a moderate to potentially high risk of rip
currents is expected this coming weekend through early next week
(16th through possibly the 19th) as long period and larger
swells from the distant northward passage of Tropical Cyclone
Jose, becomes more pronounced along our shores.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$
Synopsis...Robertson/Drag 1056
Near Term...Drag/Klein 1056
Short Term...Drag/Klein 1056
Long Term...Robertson 1056
Aviation...Drag/Klein/Robertson 1056
Marine...Drag/Klein/Robertson 1056



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