134
FXUS61 KPHI 222018
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
318 PM EST Fri Nov 22 2024

.SYNOPSIS...
Low pressure will linger across the Middle Atlantic region
through tonight. The low will then move away through the weekend.
Weak high pressure arrives for later Sunday and Monday, followed
by a cold front Monday night into Tuesday. A low pressure system
may affect the area around the Thanksgiving Day timeframe.

&&

.NEAR TERM /THROUGH SATURDAY/...
315 PM...As of mid afternoon, low pressure continues to
retrograde north and westward and has moved from NY State into
NE PA. This system has become "vertically stacked" meaning it`s
basically collocated with a large upper level low. Precip
continues to pinwheel around the system from NW to SE making its
way into our forecast area. With temperatures generally in the
low to mid 30s across our northern zones over NE PA into NW NJ,
it continues to fall mainly as wet snow in the higher elevations
with some mixing below 1000 feet or so. Higher elevations could
get another inch or so of snow before it starts to wind down
this evening. Also, as temperatures start to drop off heading
past sunset, this could cause wet roads to become ice covered
and slippery. For these reasons, we extend the winter headlines
(Winter Storm Warning for Carbon and Monroe Counties in PA,
Winter Weather Advisories for Northampton, Warren, Sussex,
Morris Counties) until 7 PM this evening. Farther south, there
has even been some snow mixing in with the rain towards the I-95
corridor however it`s too warm for anything to really stick.
Things won`t change too much through this afternoon with periods
of light snow/rain continuing across the area.

Heading into the evening and overnight periods, light snow/rain
will gradually diminish with time from NW to SE. It should be
mainly out of our eastern PA zones by the overnight period but
may linger most of the night closer to the coast (though near
the coast it should be mainly just rain). Any additional snow
accumulation in the north should be very little (less than an
inch), if any. Winds will stay elevated and it will remain
relatively cloudy, so have lows mostly above freezing except in
the Poconos and NW NJ.

For Saturday, the low continues to pull away from the area as it
moves into the Canadian Maritimes. This should help bring us at
least some partial sunshine, especially south. Highs will
rebound around 10 degrees from today, though again, with the
gusty wind it will feel cooler. Generally expect NW winds 15 to
20 gusting up to 30 mph at times.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
A dry period from Sat night into Monday. While upper heights build
along the East coast, a surface ridge will extend across the
Middle Atlantic region. Skies will be partly to mostly sunny
both Mon/Tue with perhaps a few clouds increasing later Tue
afternoon. Temperatures both days will be a little above normal
with highs in the mid/upper 50s across Delmarva, metro Philadelphia
and south NJ. For the southern Poconos and north NJ, highs will
be close to 50 degrees. Lows Sun night will be in the upper 30s
to low 40s for the metro and Delmarva areas and low/mid 30s for
rural spots.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
We`ll start the long term with the last of the mild air across the
region being swept away with a cold front passage. The low pressure
system associated with the front will be across southern Canada and
will be tracking down the St. lawrence Valley. Pops will continue to
be in the high-chance/low-likely range for now with the higher
chances to the north/west. Temperatures look too mild for any snow
attm. Lows Mon night will be in the 40s with some upper 30s far N/W.

Following that, for the Tue-Wed periods we`ll have dry conditions as
high pressure builds over the area. Temperatures will still be above
normal Tue as the cold advection doesn`t really kick in until later
in the day. By Wed. readings will have dropped back to a little
below normal with highs in the upper 40s N/W and low 50s elsewhere.

The high pressure area weakens and then moves offshore Wed night, so
while dry weather should continue overnight, clouds will increase
overnight as another low develops across the lower Ohio Valley and
begins to track east. This new system will bring chances for
precipitation for Thursday and Thursday night across the area. It
appears to be a rain event attm with some snow across the southern
Poconos and north NJ. The low will strengthen as it moves offshore,
so there is some potential for precipitation to continue into Friday.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

This afternoon...The trend will be for conditions to continue
lowering with IFR likely by this evening for most sites with the
possible exception of ACY. This will be due to low cigs and
visbys in periods of rain/snow mixed (mainly rain south of PHL)
W to SW winds generally 10 to 15 kt with 20 to 25 kt gusts.
Moderate confidence.

Tonight...IFR with rain/snow ending around the late evening /
early overnight timeframe but low clouds and mist lingering
much of the night keeping it from getting better than MVFR.
Winds remaining W to SW 10 kts or so. Moderate confidence.

Saturday...Breaking to VFR early and remaining VFR thru the day.
Wind remaining gusty from the W to NW 10-15 kts with gust to 25
kts. Moderate confidence.

Outlook...

Saturday night through Monday...VFR expected.

Monday night... sub-VFR conditions possible with light rain
 expected.

Tuesday through Wednesday... VFR expected.

&&

.MARINE...
Winds/seas remain elevated through Saturday. For this afternoon
through tonight, we will continue to see some marginal Gale
conditions at times for our southern waters off the coast of
southern NJ, DE, and the DE Bay. Farther north, the winds
should stay below Gale. For Saturday, winds should diminish
below Gale For the Delaware Bay but increase for our northern
ocean zones off the coast of Ocean and Monmouth Counties in NJ
where a Gale Warning is in effect beginning at 6 AM and
continuing through the day.

Outlook...

Saturday night through Sunday...Small Craft Advisory criteria
conditions expected. West to northwest winds 20-25 kts with gusts up
to 30 kts and seas 3-6 feet. Gale force wind gusts may linger into
the first half of Saturday night, most likely south of Great Egg
Inlet.

Sunday night through Monday night...sub-SCA expected. Fair
 except for a few showers possible Mon night.

Tuesday... SCA possible. Fair weather.

&&

.CLIMATE...
Driest autumn (Sep-Nov) on record, and any 3-calendar month
period on record, plus current status:

                   9/1-11/21   Driest          Driest 3         Year/
Site              2024 precip  Autumn Year  Calendar months    months
Allentown (ABE)       2.60      3.81  1922      3.58        Oct-Dec 1928
A.C. Airport (ACY)    2.17      3.34  2001      2.35        Oct-Dec 1946
A.C. Marina (55N)     1.58      2.89  1941      2.52        Aug-Oct 1895
Georgetown (GED)      1.17      2.67  2001      2.20        Aug-Oct 2024
Mount Pocono (MPO)    4.25      4.21  1931      3.36        Oct-Dec 1928
Philadelphia (PHL)    1.98      2.37  1922      2.37        Sep-Nov 1922
Reading (RDG)         2.20      2.89  1922      2.89        Sep-Nov 1922
Trenton (TTN)         1.86      3.18  1922      2.66        Jun-Aug 1966
Wilmington (ILG)      1.61      3.17  1922      3.17        Sep-Nov 1922

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 7 PM EST this evening for PAZ062.
     Winter Storm Warning until 7 PM EST this evening for PAZ054-
     055.
NJ...Winter Weather Advisory until 7 PM EST this evening for NJZ001-
     007-008.
DE...None.
MD...None.
MARINE...Gale Warning until 6 AM EST Saturday for ANZ430-431.
     Small Craft Advisory until 6 AM EST Saturday for ANZ450-451.
     Gale Warning from 6 AM to 6 PM EST Saturday for ANZ450-451.
     Gale Warning until 6 PM EST Saturday for ANZ452>455.

&&

$$

SYNOPSIS...Fitzsimmons/RCM
NEAR TERM...Fitzsimmons/RCM
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...Fitzsimmons/OHara
MARINE...Fitzsimmons/OHara
CLIMATE...