Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 112103
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
403 PM EST Mon Dec 11 2017

.SYNOPSIS...
High pressure over southeast Canada moves east and offshore
tonight. Low pressure moving through the Great Lakes will pass
north of the area on Tuesday and drag a cold front through the
region by Tuesday evening. High pressure builds in from the west
on Wednesday, and then weak low passes through on Thursday. A
coastal low may affect the region on Friday, and then high
pressure returns for the weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
High pressure offshore will move to the east tonight while
strengthening low pressure moves towards the lower Great Lakes
region. These features will bring increasing clouds to the area
tonight along with a slowly increasing srly winds. Low
temperatures will range from the mid/upper 20s across the north
to the low 30s over metro Philadelphia and Delmarva. Light snows
will likely affect the srn Poconos and nrn NJ well after
midnight. We have increasing pops for these areas with small
(around 1 inch) accumulations for the higher elevations.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Low pressure will continue to strengthen while moving across NY
and into New England Tuesday. Light snows across the north will
continue through the morning and then diminish as a cold front
crosses the area. Further south, the chc for measurable precip
will be less, but some light snows are possible and areas
further south will have light rains. A limited confid fcst with
regards to qpf amts. After the cold front crosses the area,
winds will shift to W and increase to 15 to 25 mph with gusts
over 30 mph. Temperatures will be highest early in the day, then
fall through the afternoon, as the cold air advection
increases.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
The long-term period continues to show a long-wave trof pattern
over the eastern US with several shortwave trofs rotating
through. The trof is deepest at the beginning period Tuesday
night with a roughly 505dam closed upper low forecast over NY
state. The associated surface low will deepen as it moves
northeast from New England into Canada, maintaining strong NW
winds and CAA over the area through Wednesday. Some snow showers
are possible, mainly over the Poconos.

For Thursday and Friday, temperatures should moderate slightly
but remain well below normal. A couple of fast-moving low
pressure centers could scoot past to our south and possibly
bring some light snow to the area.

The outlook for next weekend attm suggests temperatures
returning to near normal. Saturday looks mainly dry, but by
Sunday another low pressure may approach from the SW and bring a
a mix of rain and snow late Sunday into Monday. Confidence in
this system is rather low.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
Tonight...VFR. Increasing clouds. W winds 5 to 10 knots early
will become light. After midnight, winds will increase from the
S/SE reaching 10-15 knots by dawn. Few snow showers psbl N/W
late.

Tuesday...VFR. Few snow/rain showers N/W during the morning with VFR
cigs expected. S winds 10-15 knots will become SW as a cold front
approaches. Winds will shift to W behind the front and gusts 25 to
30 knots probable by late afternoon.

OUTLOOK...

Tuesday night through Wednesday...Mainly VFR conditions expected
but possible MVFR at times at RDG/ABE with snow showers. Gusty
west to northwest winds around 15 to 25 knots with gusts around
40 knots possible. Confidence: High

Moderate

Thursday through Friday...Mainly VFR conditions expected. MVFR
or lower possible in snow showers. West to southwest winds
around 5 to 10 kts. Confidence: Moderate

Saturday...Vfr conditions expected. Southwest winds around 10 kt.
Confidence: Low

&&

.MARINE...
Winds and seas will build late tonight and Tuesday ahead of a
deepening low pressure system and approaching front. A SCA flag
will be raised for the waters beginning at 11Z Tuesday. Fair
weather tonight and sct rain/snow showers across the Nrn NJ
waters Tuesday.

OUTLOOK...
Tuesday night through Wednesday...Strong west winds with gale
force gusts likely. Seas will also remain elevated around 5 to 7
feet on the ocean. Seas will start to subside Wednesday night.

Thursday through Friday...Sub-SCA conditions expected.

Saturday...Small Craft Advisory conditions possible. West winds
with gusts around 25 knots possible.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Gale Watch from Tuesday evening through Wednesday afternoon
     for ANZ430-431-450>455.
     Small Craft Advisory from 6 AM to 6 PM EST Tuesday for ANZ430-
     431-450>455.

&&

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



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