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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 211347
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
947 AM EDT Wed Jun 21 2017

.SYNOPSIS...
A weak upper trough and front will affect the weather today and
tonight. High pressure will build in for Thursday and Thursday
night. A low pressure system and slow moving front will bring
unsettled conditions for Friday and Saturday. High pressure will
build across the area early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
High pressure over the Atlantic will influence our weather
today keeping our region in a warm southwest flow.

The mid level short wave trough continues to make gradual
progress east and the axis is expected to move over the region
through the afternoon. As it does so, the lift associated with
that feature, combined with some limited instability (generally
CAPE values of less than 500 J/kg), could be enough for isolated
to scattered thunderstorms to develop. There is an area of
relatively high 0 to 6km bulk shear (near 40 KT). As such, we
have a marginal risk for severe storms today, with a primary
hazard of strong winds. It still appears that the highest
potential for thunderstorms will be in the Poconos and the
Lehigh Valley into northern and central New Jersey, and perhaps
on the upper Delmarva.

The wind should be from the southwest around 6 to 12 MPH and
maximum temperatures are anticipated to favor the 80s.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
A mid level ridge is forecast to build toward our region from
the west tonight bringing dry weather conditions. A weak and
dissipating cold front is expected to drop into our region from
the northwest late tonight possibly accompanied by a few clouds.

A light southwest wind is expected to become northwest. Low
temperatures are forecast to range from the middle and upper 50s
in the Poconos and in far northern New Jersey to the middle and
upper 60s on the coastal plain.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Weak high pressure will be across the region Thursday and the
beginning of Thursday night, so overall these two periods will
feature dry weather across most areas. A couple evening
showers/tstms could develop across the southern Poconos, so we
have some light chc pops for then. It will be very warm and
humid Thursday with highs in the mid 80s to around 90 across the
areas from the lehihg Valley and central NJ and south. Highs in
the souther Poconos and the higher elevations of north NJ will
be mostly in the upper 70s to low 80s.

A developing upper trough over the Great Lakes and several weak
disturbances will affect the area from Friday thru Saturday
night. Pops Friday will be in the low likely category across the
N/W areas while they taper to chc pops elsewhere. Pops during
the other periods will be more chancy favoring the wrn areas Fri
night and the southern counties Sat and Sat night. It`s
possible that some of the moisture from TS Cindy could arrive
Sat, so it`s possible that pops across the srn areas could go
higher than presently advertised. Temperatures will be above
normal Fri, but moderate back to near normal for Saturday.

There are no big systems in the later part of the long term.
Still, several weak impulses and fronts could offer the
possibility of a few showers both Sunday and Monday. We have
20-30pct pops for those time frames. Temperatures will be mostly
near normal. Dry weather is expected Tue. Since an upper trough
will be deepening over the area, temperatures will be below
normal.

&&

.AVIATION /14Z 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 with areas
of high and mid level clouds this morning giving way to mainly
scattered cloud cover for this afternoon and tonight.

There may be isolated showers and thunderstorms in the area
this afternoon. However, their potential is too low to include
in the TAFs.

A light southwest wind this morning is anticipated to increase
around 10 knots during the daylight hours. A light southwest
wind this evening is expected to become northwest overnight.

OUTLOOK...
Thu/Thu night...VFR expected.

Fri thru Sat night...Mostly VFR, but a few sct showers and
tstms could bring lower conditions.

Sun...Mostly VFR.

&&

.MARINE...
High pressure over the Atlantic will influence the coastal
waters of New Jersey and Delaware into this evening with a weak
cold front arriving from the northwest late tonight.

A southwest wind at 5 to 15 knots is expected for today and
this evening. The wind should become northwest at 5 to 10 knots
late tonight.

Wave heights on our ocean waters will favor the 2 to 4 foot
range and waves on Delaware Bay will be 2 feet or less.

OUTLOOK...
Thu/Thu night...Sub-SCA conditions.

Fri thru Sat night...Sub-SCA on Del bay. Marginal SCA seas on
the ocean. Few Showers and Tstms.

Sunday...Sub-SCA expected.

RIP CURRENTS...
We will continue with the moderate risk for the development of
dangerous rip currents for today along the coast of Delaware and
New Jersey. We are expecting a 6 second southerly wind swell on
top of a long period (around 13 to 14 second) southeasterly
ground swell.

Similar conditions are anticipated tonight into Thursday.

&&

.TIDES/COASTAL FLOODING...
Very high astronomical tides are expected in association with
the new moon on Friday. That, combined with a brief period of on
shore flow on Thursday could result in minor coastal flooding
with the Thursday afternoon and evening high tide primarily for
the Atlantic coastal areas and the shores of the Delaware Bay.
Minor coastal flooding may continue with the Friday afternoon
and evening high tide.

&&

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

&&

$$
Synopsis...O`Hara
Near Term...Iovino/Johnson
Short Term...Iovino
Long Term...O`Hara
Aviation...Iovino/O`Hara
Marine...Iovino/O`Hara
Tides/Coastal Flooding...