Jack Frost

000
FXUS61 KPHI 151804
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
204 PM EDT Tue Sep 15 2026

.WHAT HAS CHANGED...
Chances for showers have ticked up a bit for Thursday night but
otherwise no major changes to the forecast. All sections
updated. 

&&

.KEY MESSAGES...
1. Mainly quiet this week with high pressure in control.  

2. Somewhat unsettled weather will be possible at times late 
this week and next weekend as multiple systems move through. 
However at this point significant impacts due not appear likely.

&&

.DISCUSSION...
KEY MESSAGE 1...Dry and tranquil weather will persist through at 
least Thursday with a gradual warming trend. 

An expansive area of high pressure will remain in control through 
Thursday resulting in a stretch of nice mid-September days.

For tonight, with the surface high lingering near the area it will 
result in another night of mainly clear skies and light winds 
leading to good radiational cooling conditions. It won't be quite as 
cool as last night in most places but generally expecting most areas 
to get down into the 50s with some upper 40s possible in the 
Poconos. 

Wednesday through Thursday will feature a gradual warming trend as 
high pressure slips off to our south as a weak system moves in north 
of the region by Thursday. This will result in a SW flow developing 
with warm air advection. Generally expect highs in the 80s with dew 
points also creeping up through this period as well. Both days 
should be largely free of any precipitation though by late day 
Thursday an approaching cold front from the north could result 
in a few showers affecting the Lehigh Valley into the southern 
Poconos. POPs though are only around 20-30 percent. 

KEY MESSAGE 2...Somewhat unsettled weather will be possible at
times late this week and next weekend as multiple systems move 
through. However at this point significant impacts due not 
appear likely.

A cold front still looks to move southward through the area Thursday 
night into Friday and this could result in some showers. Guidance 
had been backing off on precipitation with this but some of our 
latest guidance is a bit more robust once again with showers moving 
through. The bottom line though is that with the timing mainly at 
night and mostly just showers expected (probability for thunder is 
low) this should not be an impactful system. 

A couple showers could linger into Friday over our southern zones 
but otherwise it should be a partly to mostly sunny day with 
temperatures cooling slightly compared to Thursday in the wake of 
the front. 

Looking ahead to the weekend, the aformentioned front looks to 
eventually move back to the north as a warm front late Saturday into 
Saturday night. The front may then linger near the area Sunday. As 
this occurs, moisture looks to surge back northward towards the area 
ahead of a tough moving through the Great Plains. This will bring 
increasing chances for showers and perhaps a few storms by late 
Saturday night and especially on Sunday which looks to be the wetter 
of the two weekend days. POPs for Sunday range from around 30% south 
up to 60% north. 

Medium range guidance shows the unsettled period potentially 
continuing into early next week with multiple waves of low pressure 
moving through. Still over 5 days out, so things could change with 
the forecast and it is a bit early to get into specific impacts. 
However, there is no real overwhelming signal in both deterministic 
and ensembles of any major impacts at this time with these systems.

&&

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

Through tonight...VFR. Light southeast winds (generally around
4-7 knots) becoming light and variable by the late evening into
the overnight. High confidence. 

Wednesday...Continuing VFR. Winds mainly southwest around 5-10
knots except more southerly at MIV and ACY. High confidence.

Outlook... 

Wednesday night through Saturday...Mainly VFR except some
showers Thursday night could result in brief restrictions. Also
can't rule out a few showers by late Saturday but chances for
this are low. 

Sunday...Chances for showers increases and this could result in
some restrictions. 

&&

.MARINE...
Sub-SCA conditions through Wednesday with seas generally around
2-3 feet. 

Outlook...

Wednesday night through Sunday...No marine headlines expected. 

Rip Currents...

Today...While winds will be onshore today, they will be light
and only 5 to 10 MPH. Breaking waves of 1 to 2 feet expected
with a 6 to 9 second period. With light winds and low breaking
wave heights with a medium period swell, elected for a LOW risk
of rip currents at all beaches. 

Wednesday...Tranquil conditions continue with 1 to 2 foot waves
and a light south/southeasterly wind around 5 to 10 MPH. A 6 to
8 second period is expected. These conditions will result in
another LOW risk for the development of rip currents. 

For specific beach forecasts, visit weather.gov/beach/phi

&&

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

&&

$$

DISCUSSION...Fitzsimmons/Hoeflich
AVIATION...Fitzsimmons/Hoeflich
MARINE...DeSilva/Fitzsimmons/Hoeflich