Rising Sun-Lebanon, Delaware 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

175
FXUS61 KPHI 201034
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
634 AM EDT Fri Jun 20 2025

.SYNOPSIS...
Canadian high pressure will briefly bring some relief from the
heat today. High pressure in the western Atlantic should then
build westward some through the weekend and persist for the
first half of next week, resulting in the return of the heat and
humidity. The high may then settle more to the south and west
Wednesday and Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Cold front crossing the region early this morning promises to
drop humidity and heat a couple notches for today. Enjoy it
while it lasts, as it won`t last long. While we`ll start out
fairly sunny this morning, upper level shortwave swinging
through this afternoon will act on strong insolation to bring
enough instability across our northern zones for a stray shower
or thunderstorm, so have upped POPs to isolated/slight chance.
Further south generally expect dry conditions, though it will be
breezy with clouds building during the afternoon everywhere.
Highs in the 80s, except 70s Poconos, and dew points well down
into the 60s (50s far north) will make it much more comfortable
than yesterday.

Warm front starts creeping back northward into the region
tonight, with flow turning southwesterly and dew points starting
to creep back up. Clouds will increase with the warm front and
we could see a stray shower in the far north. With the clouds
and southwesterly flow, lows will be several degrees milder than
tonight, with 60s to around 70 expected.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Ridging aloft initially situated over the southern and central US
will expand and shift northeastward into the Mid-Atlantic through
the weekend. A shortwave will dive southeastward across portions of
New England Saturday evening into Saturday night, and may glance
northeastern PA and northern NJ.

At the surface, high pressure will continue to take hold across the
area during the day on Saturday. Under mostly sunny skies,
temperatures will warm into the upper 80s to near 90 outside of the
Poconos and coastal regions, where the low to mid 80s can be
expected. Dewpoints will generally be in the mid 60s, so while it
will be warm, significant heat impacts are not anticipated.

Saturday evening, a subtle surface trough is expected to pass
through the area. For most of the area, this will not bring any real
change to the weather other than maybe some increasing clouds.
Across far northern portions of the area where ascent from the
shortwave is greater, there could be enough of an impetus for an
isolated storm or two. Should a storm form, it could potentially be
severe, with the environment being characterized by modest
instability (around 1000 J/kg MLCAPE) and deep layer shear around 35-
40 kt.

With high pressure and plentiful sunshine on Sunday, temperatures
are once again expected to climb quickly. Highs are expected to be
near 90 in the Poconos and along the coast, and in the mid 90s
elsewhere. With dewpoints rising into the low 70s, heat indices are
expected to be in the upper 90s to near 100 for most of our inland
areas away from the Poconos. Heat headlines will likely be necessary
in future updates.

Sunday night is expected to remain warm and muggy, with lows
generally in the low to mid 70s. It is plausible that locations in
the urban corridor could not fall below the upper 70s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Summary...Dangerous heat into midweek. An Extreme Heat Watch was
issued for southeastern PA, northern Delaware, and for areas
along and north of the I-95 corridor in New Jersey.

Synoptic Overview...An expansive upper-level ridge is forecast
to become situated over our region the first half of next week,
before it may weaken some and slide a bit west and south during
below Small Craft Advisory criteria. the second half of the
week. At the surface, high pressure mostly dominates however a
weak trough may be in place, especially later in the week.

For Monday and Tuesday...A strong upper-level ridge is forecast
to be situated nearly over our area during this time frame.
This, along with surface high pressure building westward from
the western Atlantic, will result in very hot/humid conditions.
The combination of air temperatures well into the 90s and dew
points in the upper 60s to low 70s will result in widespread
triple digit heat indices. With high confidence in heat indices
getting to/exceeding 105, went ahead with an Extreme Heat Watch
Monday through Wednesday. Other factors considered with the
early watch for next week were the quick ramp up in temperatures
(most of June has been below normal), the lack of relief at
night (Philadelphia could see lows stay at/above 80), and the
potential duration of this event (Heat Advisories may be needed
as early as Sunday and continue potentially all the way to
Thursday). The experimental Heat Risk map also has areas within
the Watch in the highest level for heat related impacts, where
impacts in most health systems, heat sensitive industries, and
infrastructure is likely. All of these factors were nudgers to
issue the Extreme Heat Watch > 72 hours out. Both Monday and
Tuesday, Philadelphia has a chance to reach 100 degrees for the
first time since July 18, 2012.

However, the highest heat indices come Monday through Wednesday,
which is why the Watch was set for that time. Still would
expect at least Heat Advisories outside of the Watch, but cannot
rule out the watch being extend. Given the ridge aloft and the
associated subsidence with it, little or no cumulus is expected
and thus no convection. The low-level winds however should be
light enough where sea/bay breezes probably develop resulting in
at least some local cooling near the coast.

For Wednesday and Thursday...The upper-level ridge may settle a
little south and westward during this time frame. While the
heat and humidity looks to continue, it may decrease at least
some especially Thursday with some more erosion of the northern
side of the ridge. In addition, a surface trough may become
better defined and introduce a bit more clouds and also the
potential for at least some diurnally driven convection, mainly
on Thursday.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR, though a stray afternoon shower or thunderstorm is
possible, mainly at ABE. West winds around 10 knots with some
gusts to around 15 to 20 knots. High confidence.

Tonight...VFR, though a stray shower possible again mainly ABE.
Winds southwest 5-10 kts. High confidence.

Outlook...

Saturday through Tuesday...VFR. No significant weather.

&&

.MARINE...
No Marine headlines are expected for today and tonight.

Outlook...

Saturday through Tuesday...No marine headlines expected.

Rip Currents...

For today, Offshore winds 15-20 kt and decreasing with time and
decreasing wave heights. However, it looks like there will be
some longer period swell groups. For this reason, we will carry
a MODERATE risk for the development of dangerous rip currents
for the NJ beaches with a LOW risk for the Delaware Beaches.

For Saturday, mostly shore parallel wind of 10-15 kt, to
slightly onshore in spots as winds become more S/SW in the
afternoon. We`ll continue with a MODERATE risk for rip currents
for our NJ zones except for Monmouth County where the risk
should be LOW due to the flow being more shore parallel. For the
Delaware beaches we will also carry a LOW risk for the
development of dangerous rip currents.

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

&&

.CLIMATE...
Potentially record breaking heat is expected across the area next
week. Here are a look at the daily record high maximum and minimum
temperature for all of our climate sites.


Record High Temperatures
                          June 23
Site                  Record/Year
Allentown (ABE)           96/2024
AC Airport (ACY)          98/1988 & 2024
AC Marina (55N)           91/1909
Georgetown (GED)         100/1988
Mount Pocono (MPO)        90/1954
Philadelphia (PHL)        98/2024
Reading (RDG)             98/2024
Trenton (TTN)             97/1894
Wilmington (ILG)         100/1894

Record Warmest Low Temperatures
                          June 23
Site                  Record/Year
Allentown (ABE)           71/2017 & 2024
AC Airport (ACY)          75/2024
AC Marina (55N)           74/2010
Georgetown (GED)          76/1988
Mount Pocono (MPO)        69/2024
Philadelphia (PHL)        76/1888
Reading (RDG)             77/2024
Trenton (TTN)             74/2017 & 2024
Wilmington (ILG)          75/2024

Record High Temperatures
                          June 24
Site                  Record/Year
Allentown (ABE)           98/1923
AC Airport (ACY)          99/2010
AC Marina (55N)           95/2002
Georgetown (GED)          97/2010
Mount Pocono (MPO)        92/1914
Philadelphia (PHL)        99/1923
Reading (RDG)             98/1908 & 1923
Trenton (TTN)             98/1894
Wilmington (ILG)         102/1894

Record Warmest Low Temperatures
                          June 24
Site                  Record/Year
Allentown (ABE)           71/2010
AC Airport (ACY)          72/1951, 2013, 2017 & 2024
AC Marina (55N)           72/1924, 2002, 2010, 2011, 2013 & 2020
Georgetown (GED)          74/2010
Mount Pocono (MPO)        66/1960, 1964 & 2002
Philadelphia (PHL)        75/1909, 1921, 1994 & 2020
Reading (RDG)             73/1909, 1994 & 2010
Trenton (TTN)             76/1894 & 2010
Wilmington (ILG)          74/1994

Record High Temperatures
                          June 25
Site                  Record/Year
Allentown (ABE)           98/1923
AC Airport (ACY)          96/1997
AC Marina (55N)           95/1952
Georgetown (GED)          96/1952
Mount Pocono (MPO)        91/1952
Philadelphia (PHL)        98/1952
Reading (RDG)             99/1943
Trenton (TTN)             99/1997
Wilmington (ILG)          98/1894

Record Warmest Low Temperatures
                          June 25
Site                  Record/Year
Allentown (ABE)           74/1923 & 1976
AC Airport (ACY)          80/1950
AC Marina (55N)           75/1997 & 2002
Georgetown (GED)          75/2019
Mount Pocono (MPO)        69/1952
Philadelphia (PHL)        76/1909, 1976 & 2002
Reading (RDG)             75/1943 & 1949
Trenton (TTN)             75/1976
Wilmington (ILG)          75/1976

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Extreme Heat Watch from Monday morning through Wednesday
     evening for PAZ060>062-070-071-101>106.
NJ...Extreme Heat Watch from Monday morning through Wednesday
     evening for NJZ001-007>010-012-015-017>019.
DE...Extreme Heat Watch from Monday morning through Wednesday
     evening for DEZ001.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Cooper/Hoeflich/RCM
NEAR TERM...RCM
SHORT TERM...Cooper
LONG TERM...Gorse/Hoeflich
AVIATION...Cooper/Hoeflich/RCM
MARINE...Cooper/Hoeflich/RCM
CLIMATE...Hoeflich