Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 260432
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1232 AM EDT Fri May 26 2017

.SYNOPSIS...
An area of low pressure will move away to our northeast through
Friday. A weak surface trough is expected to cross the area
during the day Friday. Weak high pressure may briefly move
across the area Friday night into early Saturday. A weak low is
forecast to move along a developing stationary front to our
south Saturday into Saturday night. Another area of low pressure
is forecast to weaken as it moves into the eastern Great Lakes
Sunday into Sunday night, then an occluded frontal system is
expected to affect the area Sunday night into early Monday. A
series of cold fronts are forecast to move across the area
Monday through Wednesday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
The mid level low was passing over southern New Jersey and
vicinity around midnight. It should reach southeastern New
England around daybreak. Meanwhile, the surface low was off the
northern part of the New Jersey coast around midnight. It is
forecast to move east northeastward off the coast of Long Island
before approaching Cape Cod around daybreak.

The rain showers over our region will continue to diminish
during the balance of the night. We have removed any mention of
thunder based on the radar and lightning data trends over the
past hour or so.

The sky should remain overcast in eastern Pennsylvania and
northern and central New Jersey. Some breaks in the cloud cover
are anticipated for northeastern Maryland, Delaware and southern
New Jersey.

A southwest to west wind around 5 to 10 MPH is expected in the
southern part of our forecast area. The wind should be slower to
increase in the north. As a result, lingering low level
moisture may develop into additional low clouds and patchy fog
there.

Low temperatures are anticipated to favor the 50s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/...
The main upper low shifts into New England on Friday, with
westerly flow prevailing across the area during the day. Several
perturbations in the flow are likely to move through the area
during the day, especially in the morning. This should keep
skies partially to mostly cloudy most of the day, and may allow
for a sprinkle or light shower to occur, especially north of the
Mason-Dixon Line. The 18Z NAM has a few showers farther to the
south as a vort max rotates southeastward through the Mid-
Atlantic around midday, but there is not a lot of support from
higher-resolution guidance at the moment. As such, kept PoPs low
or non-mentionable for the most part south of the I-78/I-195
corridor.

Main sensible weather impact tomorrow may be the winds, with
some stronger mixing likely to occur during the afternoon hours.
Winds above the boundary layer are not particularly strong
(20-30 kts), but gusts of 20-30 mph are likely by afternoon
across most of the area.

Forecast max temperatures range from the mid 60s in the Poconos
to the mid 70s in the urban corridor to around 80 in southern
Delmarva.

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
An unsettled weather pattern continues for much of the extended
forecast with several periods of rain possible.

Friday night through the early part of Saturday is expected to
be mostly dry as weak high pressure quickly moves across the
area. However, later in the day, a weak area of low pressure
will be approaching from the west but passing to our south along
a developing frontal boundary to our south. Also, a short
wave/vorticity impulse is expected to move across the area
during the day, so there will be a chance of an isolated shower
during the day Saturday.

On Saturday night, the frontal boundary is expected to remain
to our south, but should begin lifting northward toward the area
Sunday. It will likely not make its way into the area until
Sunday night. There will be a chance of showers overnight
Saturday into Sunday, but the best chance of showers is expected
to be Sunday night as the occluded front moves into the area.

A series of cold fronts are forecast to move across the area
Monday through Wednesday of next week as low pressure remain
nearly stationary across southern Canada just north of the Great
Lakes region.As any short wave/vorticity impulses slide across
the area, they could lead to additional showers or thunderstorms
early next week.

High pressure tries to build back into the area for Thursday,
which would provide a dry forecast.

&&

.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Generally a mix of VFR and MVFR conditions for the balance of
the night. A light and variable wind and lingering low level
moisture could bring some IFR conditions, mainly to KRDG, KABE
and KTTN. A west wind is forecast to increase to 5 to 10 knots
at KPNE, KPHL, KILG, KMIV and KACY. Showers will continue to be
on the decrease.

VFR conditions develop Friday morning. Winds veer to the W-NW
late Friday morning, and increase to 15-20 KT with gusts up to
23 KT.

OUTLOOK...

Friday night...Generally VFR.

Saturday...Generally VFR. Showers moving into the area later in
the day, which could lead to lowering ceilings.

Saturday night-Sunday...MVFR CIGS possible. Chance of scattered
showers.

Sunday night...MVFR to IFR conditions possible with periods of
low clouds and rain.

Monday...Generally improving to VFR during the morning.
Scattered showers and thunderstorms possible during the day.

Monday night-Tuesday...Generally VFR. Chance of showers or
thunderstorms on Tuesday.

&&

.MARINE...
Small craft advisory continues, mainly for high seas, through
Friday afternoon. Seas at the buoys have increased to 5-6 feet.
Gusts to 25 KT will develop tonight, and then gusty W-NW winds
could continue to gust to 25 KT on Friday.

Showers and thunderstorms likely on the waters tonight. Gusty
winds, small hail, and frequent cloud-to-ground lightning are
all threats from these storms. Locally strong winds/rough seas
are likely in vicinity of these storms.

Winds become westerly on Friday. A light shower or two may
occur, especially off the New Jersey coast.

RIP CURRENTS...

With increasing westerly winds developing during the day
Friday, will keep a moderate risk for the development of
dangerous rip currents in the forecast.

OUTLOOK...

Friday night-Tuesday...Conditions expected to remain below
advisory levels, although winds may gust around 20 knots at
times.

&&

.TIDES/COASTAL FLOODING...
Widespread minor flooding occurred along the coasts of New
Jersey and Delaware this evening and into Raritan Bay, the back
bays and Delaware Bay. There was some locally moderate flooding
along the New Jersey shore. The high tide has all but run its
course and we will let the Coastal Flood Advisory come to an
end.

We will take a closer look at trends to determine whether
another advisory will be needed for Friday evening. The wind
should be from the west today allowing water to drain away from
the coast. However, the astronomical tides remain quite high.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ450>455.

&&

$$

Synopsis...Robertson
Near Term...Iovino
Short Term...CMS
Long Term...Robertson
Aviation...CMS/Robertson/MPS
Marine...CMS/Robertson/MPS
Tides/Coastal Flooding...Iovino


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