Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 230030
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
830 PM EDT Wed Mar 22 2017

.SYNOPSIS...
Large high pressure across the upper Great Lakes region this
afternoon will slide southeast and crest over our region Thursday. A
warm front will lift to our northwest Friday, while a backdoor cold
front pushes through the area Saturday. This front is forecast to
stall near the southern portions of the area or just to our south
into early next week. A couple of low pressure systems may form
along the boundary and move eastward as well.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
630 PM ESTF: small modifications to temp trends were made and
dewpoints were lowered significantly tonight. Overall impact on
the general forecast...almost nil.

Winds will drop off quickly through this evening as the surface
high builds closer and the pressure gradient decreases. This,
combined with the dry air that is already in place will lead to
efficient radiational cooling. As a result expect lows tonight
to be 10 to 20 degrees below normal. We could get close to
record lows (see climate section below).

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
High will pass almost directly overhead leading to light and
variable winds for much of the region. Despite the sunny conditions,
temperatures will remain 10 to 15 degrees below normal as the
continental Polar air mass will be entrenched over the region.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
High pressure will have moved east of the area by Thursday night. A
warm front will inch towards the area from the west causing clouds
to increase over the region. Rains and some mixed precipitation will
arrive across the far N/W Friday morning. The models seem to be a
bit slower with the arrival time, and this could make the difference
in p-type with even a few hours later favoring more rain over mixed.
We will continue with a mention of some sleet/freezing rain attm.
Other than that, mostly rain N/W with low likely pops by afternoon
over the srn Poconos. Limited clouds/precip S/E with temperatures
near 60 degrees by afternoon.

The weekend looks to be a split with Sat being the better weather
day and Sunday looking rather wet. The front will remain to the
north Sat with only small chc or slgt chc pops across the far north.
The front then sags southward Sunday while low pressure moves along
it and approaches from the West. We will carry low likely pops in
most areas Sunday. Temperatures well above normal Saturday with 60s
north and low 70s South/east. Readings closer to normal Sunday.

Unsettled conditions early next week with an upper low and sfc front
lingering across the area.  We will carry chc pops for both Monday
ad Tuesday with this fcst. The north/west counties will be favored
for the better chcs for measurable rain. Temperatures early next
week should remain a little above normal for late March.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
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 few, if any,
clouds. Northwest winds will drop off quickly after 00Z, dropping
below 10 kt no later than 06Z. By 18Z tomorrow, winds especially at
Delmarva and south NJ sites (ILG, ACY, and MIV) could become light
and variable as the center of the high passes almost directly
overhead.

OUTLOOK...

Thu night...In general VFR. Low clouds psbl far NW late.
Fri...VFR most areas but restrictions psbl with rain and a
      chance for sleet and freezing rain far N/W Fri morning.
Fri night and Sat...mostly VFR.
Sat night thru Monday...Showers. restrictions for CIG and VSBY
      psbl.

&&

.MARINE...
815PM: Converted gale to SCA southern waters.

Gale force winds will conditions through the early evening
hours, before dropping off quickly. Once winds drop below gale
force, small craft advisory conditions are expected to continue
for most, if not all of the night. By sunrise tomorrow morning,
winds and seas should be below SCA criteria.

There is a chance for light freezing spray overnight. Still
considerable uncertainty as by the time the air temperature gets
cold enough to support freezing spray, winds will be dropping off.

OUTLOOK...

Thursday night...sub-SCA conditions expected.
Fri-Fri night...SCA conditions likely on the ocean. Sub-SCA on
   Del. Bay. Showers mostly north.
Sat-Sat night...Conditions diminishing below SCA conditions.
Sun-Mon...SCA expected on the Ocean. Sub- SCA on Del Bay. Showers.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Gale Warning until 11 PM EDT this evening for ANZ450>453.
     Small Craft Advisory until 4 AM EDT Thursday for ANZ430-431-
     454-455.

&&

$$
Synopsis...O`Hara
Near Term...Johnson/drag 829
Short Term...Johnson
Long Term...O`Hara
Aviation...Johnson/O`Hara
Marine...Drag/Johnson/O`Hara 829


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