639
FXUS61 KPHI 110602
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
202 AM EDT Mon May 11 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...
1. Scattered showers will remain possible across southern parts of
the area through much of this afternoon.

2. Showers, possibly some thunderstorms, Wednesday afternoon and
Wednesday night, then much warmer air arriving over the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Scattered showers will remain possible across
southern parts of the area through much of this afternoon.

As of early this morning, an upper-level low is centered over
portions of Ontario and Quebec, with cyclonically curved flow
continuing to overspread the region. At the surface, a cold front
has moved offshore, and will continue moving southeast away from the
region through today and into tonight.

Isolated showers and some drizzle are ongoing roughly from I-95
southeastward. The northern extent of any shower activity will
continue to shift southeastward through today, but at least
scattered showers could continue to impact portions of the Delmarva
and far southern NJ into this afternoon before all precipitation
departs. Additional rainfall amounts will be quite light, with only
a few hundredths of an inch near I-95 and perhaps up to a tenth of
an inch over portions of the Delmarva.

In the wake of the cold front, temperatures will be cooler today,
only rising into the upper 50s to mid 60s for most. It will be cool
tonight, with lows generally in the low-mid 40s. Across the higher
elevations of the Poconos, temperatures are expected to fall into
the mid-upper 30s. Some patchy frost can`t be ruled out across these
areas, but winds may remain elevated enough to prevent this from
being much of a concern.


KEY MESSAGE 2...Showers, possibly some thunderstorms, Wednesday
afternoon and Wednesday night, then much warmer air arriving over
the weekend.

The upper-level pattern is forecast to become rather amplified
through this week. A strong upper-level trough axis shifts to our
east Tuesday as high pressure will also be shifting offshore.
Another upper-level trough then arrives into the East Wednesday into
Thursday before lifting out Friday into Saturday. The ECMWF in
particular continues to close this trough off across the Mid-
Atlantic and Northeast by later Wednesday into Thursday. Other
guidance continues with the idea that the trough sharpens but
remains open as it crosses our region. Regardless of how this
transpires, a round of showers is probable Wednesday afternoon and
Wednesday night as a trough and cold front arrives.

As the aforementioned upper-level trough moves into the region
Wednesday, low-level warm air advection will increase ahead of it as
the low to mid level flow also increases. This will result in an
increase in forcing for ascent, and some instability should develop
ahead of the main forcing. A warm front should also lift across our
area Wednesday with some ascent associated with it. As a result,
showers should increase Wednesday from west to east, especially in
the afternoon with these peaking Wednesday night as the cold front
arrives. The amount of destabilization is more uncertain, however
guidance does show some instability which should be enough to
support at least a few thunderstorms. The intensity of any
thunderstorms however will depend on the magnitude of the
instability and shear. If some convection is able to become stronger
then locally gusty winds will be possible.

The main forcing should shift to our east and northeast Thursday
with the bulk of the showers ending. However, if the closed low
scenario ends up happening, then the core of the cold air aloft with
this slides overhead and this could result in additional shower
development during Thursday and possibly into Friday before the
system departs our region. As the trough lifts out and more of a
ridge starts to arrive this weekend, a drier and much warmer air
mass will overspread our area.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Through 12Z...Primarily VFR. A few light showers or BR could lead to
brief visibility restrictions for the I-95 terminals, MIV, and ACY.
Winds generally north at 5-10 kt. Moderate confidence.

Today...Primarily VFR. A few light showers could lead to brief
visibility restrictions for MIV and ACY through 18-20Z before any
showers move offshore. Winds generally north-northwest at 5-10 kt,
though they may become southeasterly for a time this afternoon at
MIV and ACY. Moderate confidence.

Tonight...VFR. Winds generally northwest at 5 kt or less. High
confidence.

Outlook...

Tuesday...VFR.

Wednesday...VFR conditions lower to MVFR or IFR later in the
afternoon and at night along with showers. A few thunderstorms
possible later in the afternoon and evening. Southerly wind gusts up
to 25 knots possible during the afternoon.

Thursday...Times of sub-VFR conditions and some showers possible.

Friday...Mostly VFR. A few showers possible.

&&

.MARINE...
No marine headlines are currently in effect. North winds early this
morning will generally be 10-15 kt with gusts around 20 kt. A short
window of gusts near 25 kt is possible, but confidence is not high
enough to warrant Small Craft Advisory issuance. Winds will decrease
further this afternoon. Another uptick in winds is possible tonight,
but still below SCA criteria. Seas 2-4 feet this morning, decreasing
to 1-3 feet this afternoon through tonight. Scattered showers will
be possible for the southern NJ and DE coastal waters through this
afternoon.

Outlook...

Tuesday...The conditions are anticipated to be below Small Craft
Advisory criteria.

Wednesday...Small Craft Advisory conditions probable.

Thursday and Friday...The conditions are anticipated to be below
Small Craft Advisory criteria

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

DISCUSSION...Cooper/Gorse
AVIATION...Cooper/Gorse
MARINE...Cooper/Gorse