Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 151850
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
250 PM EDT Sat Jul 15 2017

.SYNOPSIS...
In the wake of the cold front which moved off shore earlier today,
high pressure will stay over our region through the remainder of the
weekend. A trough will approach and stall just west of our region
Monday through Wednesday. Another cold front will slowly drop down
from the north late next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Scattered showers and isolated thunder have developed across DE
and SE NJ this afternoon as the last energy associated with the
front crosses the area. A couple downpours and locally gusty
winds will be over these areas for the next few hours.

Later, skies will become partly cloudy as high pressure with
drier air begins to build over the region. Low temperatures
tonight should drop into the low 60s across the N/W areas and
remain the upper 60s to around 70 in Philadelphia and over
Delmarva. Winds will be light tonight. A little patchy fog is
possible over Delmarva and Srn NJ where there were some showers
today.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
The upper trough will be east of the area and high pressure will
settle over the area Sunday. Fair weather is expected. The
airmass will be rather dry, similar to what is across the N/W
areas today. High temperatures should climb into the mid 80s
easily in most areas. It will be cool along the shore with a sea
breeze expected. Across the southern Poconos, readings will
reach the upper 70s to low 80s. Winds will be light early, then
turn S or SW at around 10 mph by afternoon.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
High pressure builds across the region on Sunday. Plenty of
sunshine on tap with warm and mild conditions. Highs top off in
the mid and upper 80s throughout the region with relatively
comfortable humidity levels as surface dewpoints will be in the
low to mid 60s.

The pattern then changes as high pressure moves offshore Sunday
night. Return flow sets up behind the departing high, and
humidity levels build back up as dewpoints climb into the mid
and upper 60s, and possibly into the lower 70s across NE MD and
DE. During this time, H5 trough with several shortwaves rotating
around the base of the trough will move east, with the trough
digging from the Ohio Valley and Northeast down into the
Southeast. This trough will become nearly stationary along the
East Coast Monday and Tuesday, and several weak areas of low
pressure will develop on the stationary front along the Mid-
Atlantic and pass through the region during the start of the new
week.

Best chances for precip will be over the Lehigh Valley and
Pocono Mountains Monday afternoon as surface low pressure
develops on the boundary over the Mid-Atlantic, and then lifts
to the north throughout the day and moves offshore Monday night.
The upper trough remains along the coast, and another shortwave
dives into the base of the trough on Tuesday. Another surface
low develops Tuesday afternoon and passes through the region
Tuesday night.

Surface high pressure builds in from the west on Wednesday, and
the upper trough will be slow to depart. As a result, this
keeps at least a slight chance/chance for showers/thunderstorms
in the forecast on Wednesday.

High pressure moves offshore Wednesday night/Thursday morning.
From there, several weak cold fronts approach from the west for
Thursday and Friday. Each front could touch off at least
isolated to scattered showers and thunderstorms.

The warmest temps during the week look to occur on Wednesday
and Thursday, when a southwest flow ushers a hot and humid
airmass into the region with highs in the upper 80s to low 90s
and surface dewpoints in the upper 60s to low 70s. Dewpoints may
back off a bit on Friday behind one of the weak cold fronts.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

A few showers may move across KACY through about 5 p.m. with
lower CIGS/VSBYS possible, but other than that, VFR conditions
should be at the terminals tonight and Sunday. High pressure
with drier air is making its away across the region this afternoon
and it should remain through Sunday. There will still be some
VFR-level CIGS across the N/W areas through the evening, but
bases should remain 040-060. Winds will be mostly NW this afternoon
with speeds under 10 knots. Winds will trend back to (more) wrly
for Sunday.

OUTLOOK...

Sunday through Sunday night...VFR conditions expected. Light
and variable winds, becoming SW 5-10 KT. Light and variable
winds at night.

Monday through Wednesday...Mainly VFR conditions expected.
Afternoon showers and thunderstorms with MVFR or lower
conditions possible. South to southeast winds around 10 knots.

Thursday...VFR conditions expected. SW winds 5-10 KT.

&&

.MARINE...
The conditions are expected to remain below Small Craft
Advisory criteria today and tonight. A cold front is forecast to
shift off the coast this morning then stall offshore and to our
south. An easterly surface wind has been continuing across the
northern coastal waters, however all areas will see a wind shift
to the west and northwest this morning behind the front. The
flow looks light enough though where the winds should turn
southerly this afternoon and into this evening especially for
the New Jersey coastal waters.

OUTLOOK...

Sunday through Thursday...Sub-SCA conditions expected on the
waters. Scattered showers and thunderstorms possible, mainly
during the afternoon and early evening hours Monday through
Wednesday. Heavy rain, gusty winds, and lightning can accompany
those thunderstorms.

.RIP CURRENTS...
We expect that with the light winds and no significant seas
across the area that the rip current risk will be LOW for Sunday.

&&

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

&&

$$
Synopsis...
Near Term...O`Hara
Short Term...O`Hara
Long Term...
Aviation...O`Hara
Marine...O`Hara



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