064
FXUS61 KPHI 181308
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
908 AM EDT Sun Oct 18 2026

.WHAT HAS CHANGED...
Freeze Warning has expired. Updated Key Message 1.

&&

.KEY MESSAGES...
1. A cold airmass continues this weekend. Another round of
frost is possible tonight into Monday morning.

2. Uncertainty persists regarding a nor`easter developing off
the coast of the southern Mid-Atlantic that may cause unsettled
conditions and hazardous marine impacts early next week.

&&

.DISCUSSION...
KEY MESSAGE 1. A cold airmass continues this weekend. Another round of
frost is possible tonight into Monday morning.

The Freeze Warning expired at 9 AM. Temperatures early this morning
dropped to or below freezing across portions of eastern Pennsylvania
and northern New Jersey. Given the widespread freezing temperatures
observed, the 2026 growing season has ended for the following counties...

In Pennsylvania...Carbon, Monroe and Northampton counties.

In New Jersey...Sussex and Warren counties.

No additional frost/freeze headlines will be issued for these counties
until Spring 2027.

Sunny and chilly today with highs about 10 degrees below average,
topping off mostly in the upper 50s.

Another cold night on tap for tonight, and additional frost and/or
freeze headlines may be needed for areas where the growing season
continues.

Temperatures will then begin to slowly moderate into early this week.


KEY MESSAGE 2...Uncertainty persists regarding a Nor`easter
developing off the coast of the southern Mid-Atlantic that may
cause unsettled conditions and hazardous marine impacts early
next week.

The base of a deep trough axis will pass through the region late
tonight into Sunday. As it does so, the trough axis will then
cutoff into an upper level low which will meander over the
southern Mid-Atlantic coast into early next week. At the same
time, strong and expansive high pressure will be building over
the Ohio Valley. While confidence is increasing regarding a
nor`easter developing off the North Carolina coast by Sunday
into Sunday night, it must be said there remains a vast amount
of uncertainty with regards to potential impacts to our region
into next week.

Considerable differences amongst global/ensemble guidance
exists with regards to just how close/long this system will
get/last in our region. Relative to the previous forecast
discussion, there has not been much change. The EC ensemble
member spread is fairly tightly clustered through the early part
of next week, and then begins to diverge, but generally has the
low tracking northward and then meandering off the Mid-Atlantic
coast into mid or even late week. The GEFS members are similar
until about mid-week when they begin to diverge more
substantially. All of this being said, it doesn`t appear likely
that there will be significant impacts inland from this system,
even though they can`t be entirely ruled out at this time. What
is increasingly likely though is at least some impacts to
coastal communities with periods of gusty northeast winds, some
showers, and potentially some coastal flooding concerns,
potentially for multiple days next week. We will continue to
monitor the progress of this developing system.

&&

.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR. N winds 8 to 12 kt, becoming NE. High confidence.

Tonight...VFR. NE winds 5 kt or less. High confidence.

Outlook...

Monday and Tuesday...VFR. Gusty northeast winds up to 20 kt
possible with gusts up to 30 kt also possible near KMIV and
KACY.

Wednesday and Thursday...Primarily VFR, although sub-VFR
conditions possible at times. A chance of rain showers each day,
with chances highest for KMIV and KACY. Gusty northeast winds
up to 20 kt possible with gusts up to 30 kt also possible near
KMIV and KACY.

&&

.MARINE...
Will go ahead and extend the Gale Warning for offshore waters
until noon today. Otherwise, all other headlines remain in
effect.

For Delaware Bay, Small Craft Advisories are in effect through
noon today. For the coastal ocean waters of NJ and DE, Gale
Warnings were converted to SCAs, which are in effect through
tonight. N to NE winds 15 to 20 kt with gusts up to 25 kt will
diminish this afternoon, but seas will remain elevated at 4 to 6
feet through tonight.

Outlook...

Monday through Thursday...Due to developing nor`easter off the
southern Mid-Atlantic coast, a prolonged period of gale force
conditions are expected to develop/continue across all marine
waters. A Gale Watch remains in effect for Monday through
Tuesday. Lower confidence for Wednesday and Thursday. Northeast
winds of 25-35 kt with gusts of 35-45 kt are possible. Seas of
10-16+ feet possible.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until noon EDT today for ANZ430-431.
     Small Craft Advisory until 6 AM EDT Monday for ANZ450>455.
     Gale Watch from Monday morning through Tuesday afternoon for
     ANZ451>455-480>483-485.
     Gale Warning until noon EDT today for ANZ480>483-485.

&&

$$

DISCUSSION...AKL/Cooper/Gorse/MPS/RCM
AVIATION...AKL/Cooper/MPS/RCM
MARINE...AKL/Cooper/MPS/RCM