Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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045
FXUS61 KPHI 200459
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1259 AM EDT WED JUL 20 2016

.SYNOPSIS...
High pressure will remain over the region through Friday. A cold
front may move into the area and dissipate Friday night into
Saturday. Strong high pressure then re-establishes itself into
next week, but another cold front will slowly approach from the
northwest late in the weekend.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Grid update to take into account the recent uptick in convection
over Chesapeake Bay/Delmarva region was sent shortly after
midnight. An upper shortwave trough can be seen moving
southeastward thru the DC area with another strong one digging
in behind it near the the OH-PA border. These impulses will
provide the lift for convection across our southern zones. The
last few runs of the HRRR/RAP and now the 00Z NCEP WRF ARW/NMM
have a decent handle on the ongoing convection. Expect these
showers and storms that are currently over the Delmarva to be
move/redevelop eastward into far southern NJ overnight and then
across our offshore waters by early morning.

Added enhanced wording for gusty winds and hail overnight from
about Kent Co MD to Kent Co DE southward where SPC mesoanalysis
shows a moderate amount of instability (MUCAPE 1500-2000 J/KG).
With surface temperatures in the low/mid 70s, convection is likely
non-surface-based. We`ve already seen a downward trend in storm
intensity after midnight but the potential for a storm to pulse
back up and produce large hail. Locally damaging winds now appears
to be a waning threat with convection expected to become
increasingly elevated as the nocturnal boundary layer establishes
itself farther downstream.

945 PM Discussion...
Dry air will continue to filter into our region from the
northwest and north overnight. We are anticipating a partly cloudy
sky.

There will be some lingering low level moisture in our southern
counties. A mid level short wave trough dropping over our region
during the night will continue to trigger scattered showers and
isolated thunderstorms in our Delmarva counties and on the
adjacent coastal waters.

The wind should remain relatively light. Minimum temperatures
should be in the 50s up north and in the 60s elsewhere.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
The mid-level trof axis moves off the eastern seaboard allowing
surface high pressure to build across much of the forecast area.

Temperatures tomorrow look to be the coolest of the week with mid
70s to mid 80s expected. The heat is on thereafter.

Winds won`t be as gusty tomorrow and will go southwest during the
afternoon.

We will keep very small POPs in the forecast across southern
Delaware during the morning hours.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Sfc high pres will be over the area thru Fri and there will
likely be few clouds. However, conds will be genly pleasant but
withe increasing humidity by Fri. Aloft, a large and strong h5
ridge will be parked over the mid-section of the country and will
gradually shift a bit ewd. A cdfnt will move acrs the region later
Fri aftn into Fri eve and bring probably the best chc of any
precip in the next 7 days.

There is still some uncertainty as to how much of the heat
associated with this ridge we get and when. Latest guid now
indicates the peak of the heat will be Sun and Mon, and the GFS
continues to be the hottest of the mdls and got even hotter with
its 12Z run. The ECMWF, which trended cooler last night has gotten
hotter again. Some for of heat headlines may be needed over the
weekend or into next week. The CMC a bit cooler.

Temps look to be well into the 90s Fri-Mon, with dewpoints
becoming worse by Sun and Mon. There is always the chc of some
diurnal convection in a humid ams, but the guid differs on its
extent especially around Mon.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

VFR conditions are expected through the TAF period under a partly
cloudy sky. One exception may be some MVFR visibility restrictions
around KMIV near daybreak on Wednesday.

Wind speeds are forecast to be less than 10 knots. The direction
should favor the northwest to northeast overnight, veering toward
the southeast to southwest on Wednesday.

OUTLOOK...
Wed night through Thu...VFR. High pressure. High confidence.

Fri...Mainly VFR. However, shra/tsra psbl with lcl mvfr and psbl
ifr late Fri aftn into Fri night. Moderate to high confidence.

Sat through Sun. Mainly VFR. High pressure. High confidence. A
slight chc of diurnal tsra n and w on sun aftn.

&&

.MARINE...
Tonight...We are watching strong storms developing over eastern MD
late this evening. These storms may pose a threat to mariners
(locally strong winds and higher seas as well as lightning) in
the DE Bay overnight and our southern coastal waters toward early
morning as they move eastward. Otherwise, winds and seas will
remain below Small Craft Advisory criteria. N winds will become NE
overnight. As they veer NE, they could gust into the 15 to 20 kt
range.

Wednesday...Winds and seas are not expected to reach SCA
criteria. The NE winds could continue in the 15 to 20 kt range in
the morning hours. They are expected and become more easterly in
the afternoon.

OUTLOOK...
Thu and Fri....Predominately sub-SCA conditions in S-SW flow.
However, there is a chance some wind gusts near 25 knots on Fri,
as well as increasing seas in advance of a cdfnt.

Sat and Sun...Brief elevated wind/seas are psbl early Sat before
subsiding to below SCA for the remainder of the pd.

RIP CURRENTS... The risk for the formation of dangerous rip
currents on Wednesday will be low at the DE and NJ beaches, but
very localized moderate rips are possible along the NJ coast.

We have had some reports of upwelling along the coast, where
temperatures have dropped into the low 60s.

&&

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

&&

$$
Synopsis...Nierenberg
Near Term...Iovino/Klein
Short Term...Kruzdlo
Long Term...Nierenberg
Aviation...Iovino/Nierenberg
Marine...Klein/Kruzdlo/Nierenberg



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