Whitetail

000
FXUS61 KPHI 211757
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
157 PM EDT Wed Oct 21 2026

.WHAT HAS CHANGED...
Updated key messages 1 and 3, and also the aviation and marine
sections.


&&

.KEY MESSAGES...
1. Low pressure well off the Mid-Atlantic coast will move even 
farther away Thursday, however some coastal impacts and hazardous 
marine conditions continue.

2. A prolonged period of onshore flow will lead to multiple 
elevated high tide cycles this week resulting in rounds of 
coastal flooding, with the peak being this evening.

3. Frost impacts possible Friday night and Saturday night where the 
growing season continues.

&&

.DISCUSSION...
KEY MESSAGE 1...Low pressure well off the Mid-Atlantic coast will 
move even farther away Thursday, however some coastal impacts and 
hazardous marine conditions continue.

Low pressure located well off the Mid-Atlantic coast will strengthen 
through tonight as it gradually turns more to the northeast. This 
northeast or east-northeast motion then continues on Thursday. 
Meanwhile, strong surface high pressure centered across New England 
will shift into the Canadian Maritimes tonight. A tightened pressure 
gradient remains between these two systems through tonight. 

Some impacts remain only for our coastal and marine areas. The multi-
day north-northeast wind has resulted in 10+ foot waves just 
offshore. These big waves breaking onto the beaches will result in 
some additional beach erosion especially during times of high tide. 
Peak wind gusts in the 30-40 mph range into this evening for areas 
along the coast, and 20-30 mph inland. The winds will diminish late 
this afternoon and especially tonight particularly away from the 
immediate coast. Some mid to mostly high clouds into tonight will 
occur especially closer to the coast. As the winds diminish tonight, 
it will be a chilly night, however frost is not expected.

For Thursday into Friday, the ocean storm will move farther out to 
sea as an incoming system from the northwest kicks it out. This will 
reduce the marine and coastal impacts, while keeping our weather dry 
and providing a fresh shot of chilly air. There will still be a 
notable north-northwest breeze Thursday as the pressure gradient 
remains tightened due to another incoming strong surface high from 
Canada. 


KEY MESSAGE 2...A prolonged period of onshore flow will lead to
multiple elevated high tide cycles this week resulting in 
rounds of coastal flooding, with the peak being this evening.

As the nor'easter meanders offshore through the middle of the 
week, there is a persistent and strong north-northeast wind in 
place. This prolonged period of onshore flow will result in 
multiple elevated high tide cycles. Recent forecast trends have 
been lowering on the crests of the high tide cycles for this 
event.

Water levels look to peak this evening, with fairly widespread
but minor flooding from Ocean County NJ southward through
Delaware including the Delaware shores of Delaware Bay. In some
of the back bays, moderate coastal flooding is possible with 
this evening's high tide cycle. Given lowering forecasts, did 
not have the confidence to issue a Coastal Flood Watch or
Warning. One area where conditions look notably improved is
Cumberland County NJ, where the north-northeast wind should push
water away from the bay shore and thus have cancelled the
Coastal Flood Advisory there. Beyond this evening, the 
nor'easter will gradually be moving away from the region for the
end of the week. Another round of coastal flooding is possible 
Thursday evening with spotty minor to widespread minor coastal 
flooding. This high tide cycle is forecast to be lower than 
this evening's high tide cycle.

At this time we are not forecasting any coastal flooding for the 
Maryland eastern shore. 


KEY MESSAGE 3...Frost impacts possible Friday night and Saturday 
night where the growing season continues. 

As an upper-level trough pivots across the Northeast on Friday,
a potentially strong mid level ridge in the Plains to Midwest 
shifts eastward some into the weekend. This will support strong 
surface high pressure initially centered near the Great Lakes and 
portions of eastern Canada, which then shifts eastward into the 
Northeast and Mid-Atlantic Friday and over the weekend.

A chilly and dry air mass will accompany this strong surface 
high, and as the high itself settles more overhead the winds 
will decouple. This will set the stage for efficient radiational 
cooling both Friday night and Saturday night. The forecast lows are 
in the 30s for much of the area (away from the coasts and outside of 
the urban centers) with a frost potential. It is possible that if 
the radiational cooling ends up being stronger, then some areas 
could get to freezing or a little below. Overall though, frost 
impacts are possible where the growing season remains active.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, 
KILG, KMIV, KACY and surrounding areas.

Rest of this afternoon...VFR with some high clouds. North-northeast 
winds 10-15 knots with gusts 20-25 knots at times. Moderate 
confidence.

Tonight...VFR. North-northeast winds diminishing to 10 knots or 
less, then becoming north-northwest (becoming locally light and 
variable). Moderate confidence.

Thursday...VFR. North to northwest winds increasing to 10-15 knots 
with some gusts to around 20 knots. Moderate confidence.

Outlook...

Thursday night...VFR. North-northwest winds diminishing to 10 knots 
or less.

Friday through Monday...VFR.

&&

.MARINE...
The wind field into our area has been less overall and the latest 
guidance overall continues to keep gales east of the New Jersey and 
Delaware Atlantic coastal waters. A Small Craft Advisory continues 
for the New Jersey and Delaware nearshore waters. The Small Craft 
Advisory for lower Delaware Bay goes through the day Thursday.

An area of strong low pressure well offshore will move even farther 
out to sea on Thursday. A tightened pressure gradient will remain in 
place however due to strong high pressure to our north. Gale 
Warnings continue for our offshore zones with a Small Craft Advisory 
elsewhere through Thursday. Seas 8-15 feet on the ocean, with 5-8 
foot waves into portions of lower Delaware Bay (more likely closer 
to the mouth of the bay). The winds are forecast to weaken some 
tonight.

Outlook...

Friday...Small Craft Advisory conditions probable, mainly on the 
ocean zones due to lingering 5+ foot seas.

Saturday...Winds are forecast to be below Small Craft Advisory 
criteria, however seas around 5 feet may linger for a while longer 
especially for our southern Atlantic coastal waters.

Sunday and Monday...The conditions should be below Small Craft 
Advisory criteria..

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for 
     NJZ016.
     Coastal Flood Advisory until 10 PM EDT this evening for NJZ020-
     022>027.
DE...Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for 
     DEZ001.
     Coastal Flood Advisory until 10 PM EDT this evening for 
     DEZ002>004.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ431.
     Small Craft Advisory until 8 PM EDT Friday for ANZ450>455.
     Gale Warning until 6 AM EDT Thursday for ANZ480>483-485.

&&

$$

DISCUSSION...Fitzsimmons/Gorse/RCM
AVIATION...Gorse
MARINE...Gorse