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000
FXUS61 KPHI 010253
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
953 PM EST Thu Nov 30 2023

.SYNOPSIS...
High pressure will remain in control through tonight. A low
pressure system and cold front will pass through Friday and
Friday night. The weekend will start out mostly dry on Saturday
but will become increasingly more unsettled for Sunday and into
the middle of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Nudged hourly temps up just a bit to match current obs and
trends with this update; lingering cirrus coverage and a light
breeze have resulted in a slow decrease after sunset. Winds
should diminish over the course of the next couple hours as a
sharp surface inversion develops and the clouds clear out as
well, so expect temps will then drop off for the rest of the
overnight hours, though with dew points some 10-15 degrees
higher this time tonight than last night, we`ll hold warmer
tonight in the upper 20s/low 30s.

Surface high pressure centered to our south will continue to
influence our region through tonight as it moves further
eastward offshore. However, with time, surface low pressure
currently centered over TX/OK will look to move northeastwards.
With this low pressure system forecast to swing northeastwards
through MO/IL tomorrow, some precipitation chances will be
brought to region tomorrow afternoon onwards.

Cloud cover will build in tomorrow morning rather quickly, PoPs
looking to be in the forecast by tomorrow afternoon. The overall
trend from guidance (i.e., decreasing PoPs overall with higher
chance PoPs occurring later) is continuing. Given this, will include
mainly chance PoPs for much of the region after 1PM. Mainly likely
PoPs for much of the region is included 4PM onwards. Precipitation
experienced by the region overall during the period will not be
impactful at all. At best, 0.10-0.15 inches of rainfall can be
expected.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Showers will continue Friday night into early Saturday as warm
air advection and Gulf of Mexico moisture associated with a
weakening shortwave moves through the area. Cloud cover is
expected to dominate during this timeframe, as the moisture
does not look to scour out between systems followed by a
secondary low or cold front later Sunday. It will be mild with
highs in the 50s to low/mid 60s, with the warmest day looking to
be Saturday.

There is more uncertainty on Sunday as the guidance is somewhat
split on whether we get just a cold front moving trough or low
pressure crosses our area. The latter would result in a more
widespread rain instead of some showers. Overall, it looks like
at least weak low pressure slides near or over our area and this
would keep our area more stable especially with a northeasterly
low-level flow for a time. The onshore flow scenario would tend
to result in cooler temperatures than currently forecast for
Sunday, however given the uncertainty on the synoptic features
that will be moving across or near our region we opted to just
cool the temperatures slightly from Saturday. The guidance that
has more of just a cold front moving through later Sunday,
shows some mainly elevated instability Sunday afternoon although
it is on the weak side.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The long term period of the forecast looks to be unsettled though
there remains quite a bit of uncertainty beyond early next week.

Showers will gradually decrease across the region Sunday night
into Monday as a cold front crosses the region. A rumble of
thunder or two cannot be completely ruled out, particularly
closer to the coast. However, model guidance generally depicts
only a few hundred joules per kilogram of CAPE and any
instability that does exist will drop off as we head through the
overnight hours. Chances for showers increase again for Monday
with the passage of a mid-level shortwave with high pressure
building to the south of the region for Tuesday.

Heading into the mid-week, the upper-level pattern remains
progressive. Latest model guidance generally forms a consensus that
another upper-level trough begins to develop and dig out of the
midwest and move eastward towards the Eastern Seaboard. Associated
with this deepening trough is a surface clipper system that quickly
progresses out of the Great Lakes region and into the Mid-Atlantic
during the middle of next week. This low then passes offshore and
model guidance suggests that it will rapidly strengthen once it does
so. However, uncertainty remains in how quickly the upper-level
trough deepens and therefore, model guidance differs in exactly
where and when the surface low may strengthen. As a result, PoPs for
most of the long term beyond Tuesday remain around 20 percent or
less.

Temperatures will begin above normal (highs in the 50s/low in the
40s/30s) to start the long term period then fall back to near normal
to slightly below normal (highs in the 40s/low in the 20s) for the
middle of next week.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE,
KRDG, KILG, KMIV, KACY and surrounding areas.

Tonight...VFR. SSW winds around 5 kt. High cloud cover will
move out before midnight for most sites. Expecting winds to go
light and variable, if not calm, at KRDG/KABE after 02z
tonight. Other sites will likely prevail at 5 knots or less out
of the southwest. Guidance indicates LLWS particularly for the
I-95 terminals and KRDG/KABE as a 25-35 kt low level jet moves
overhead, so have included LLWS mention at those sites through
07z. High confidence.

Friday...VFR through late afternoon. High level cloud cover
building in during the morning and ceilings lowering through
the afternoon. -SHRA works in from the southwest for most sites
by 22/23z with MVFR ceilings becoming increasingly likely (80%
chance) by that time.

Outlook...

Friday through Saturday morning...Sub-VFR at times with showers.
Moderate confidence.

Saturday afternoon/night...VFR during the day then sub-VFR at
night with showers. Low confidence.

Sunday...More low clouds/showers possible with MVFR/IFR. Low
confidence.

Sunday night...Gradually improving to VFR as showers decrease but
patchy fog is possible. Moderate confidence.

Monday...Periods of sub-VFR conditions possible with chances for
showers, particularly in the afternoon. Westerly wind gusts 20-25
knots. Shower chances and wind gusts decrease overnight. Moderate
confidence.

Tuesday...VFR. Westerly wind gusts up to 20 knots. Moderate
confidence.

&&

.MARINE...
A Small Craft Advisory is in effect until 3AM Friday for
coastal waters from Sandy Hook to Manasquan Inlet as gusts up to
25 knots and seas 3-5 feet are expected through the middle half
of the overnight hours tonight coincident with a low level jet
moving overhead. Otherwise no marine headlines are in effect.

SSW/SW flow 15-20 kts will continue until around 11PM tonight.
Thereafter, SSW/SW winds 10-15 kts can be expected through
Friday. Gusts near 20 kts are possible Friday.

2-3 foot seas this evening will build to around 3-4 feet
tonight before returning to 2-3 feet for Friday.

Outlook...

Sub-SCA for Friday and into the weekend. Rains and fog possible
Friday/Friday night and again Sunday/Sunday night into Monday.

Small Craft Advisory conditions possibly develop early Monday
morning as westerly winds begin to increase. SCA conditions are
likely by Monday evening with gusts up to 30 knots possible. Winds
decrease back below SCA criteria during the day on Tuesday. Seas of
2 to 4 feet throughout.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 3 AM EST Friday for ANZ450.

&&

$$

SYNOPSIS...AKL/OHara
NEAR TERM...Brudy/Wunderlin
SHORT TERM...Franklin/Gorse/OHara
LONG TERM...AKL
AVIATION...AKL/Brudy/OHara/Wunderlin
MARINE...AKL/Brudy/OHara/Wunderlin