Lower Macungie, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

361
FXUS61 KPHI 050851
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
351 AM EST Fri Dec 5 2025

.SYNOPSIS...
The surface high will shift offshore today into tonight.
Meanwhile, a low pressure system will be lifting off the coast of
the Carolinas further out to sea. The next cold front is expected
to cross our region Sunday into Sunday Night. In the wake of that
front, high pressure builds in for the first half of the work week,
followed by another low pressure system approaching our region
Wednesday into Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
One of the coldest mornings of the season is ongoing. Single digit
temperatures are found where skies are clear whereas a mix of teens
and 20s are found where a thick cloud deck is located this morning.
This cloud deck is associated with the area of low pressure that is
located near the Southeast coast which will track northeast off the
coast of the Outer Banks later on today.

Little in the way of change has been made to the forecast as a
whole. The precipitation shield which is currently located near
Baltimore will gradually expand northward through the morning hours.
With plentiful of cold air in place, light snow is expected across
the Delmarva and southern New Jersey this morning into the
afternoon. As surface flow becomes more onshore, a `warmer` layer of
marine air will infiltrate areas along the coast, changing these
areas over to plain rain by late morning. Snowfall amounts are still
anticipated to remain below advisory thresholds, where up to 1" inch
is expected, locally higher amounts up to 1.5" are possible across
the southern Eastern Shore of Maryland and southern Delaware.
Further north, occasional flurries and snow showers may reach as far
north as the I-78 corridor, but no accumulation in these areas is
expected. The bulk of precipitation should come to an end by mid to
late afternoon. High temperatures will range between the upper 20s
to upper 30s for most, with lower 20s in the Poconos and lower 40s
along the coast.

Tonight, low pressure near Hatteras will continue to track northeast
into the western Atlantic. As it does so, an inverted surface trough
extending out of the north side of the low will pivot through the
area. With temperatures expected to fall into the mid 20s to low
30s, residual low-level moisture trapped under an inversion, and a
subtle warm nose located just above the surface, many forecast
soundings suggest pockets of drizzle and/or freezing drizzle are
possible through the evening hours. Greatest potential for
occurrence is for locales along and southeast of the I-95 corridor,
before winding down come Saturday morning.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The big story in the short term will be the cold front crossing
through our region late Sunday into Sunday Night.

With the main trough axis to our northwest Saturday and Sunday,
surface winds will shift to southwesterly allowing a brief
warming trend. Temperatures will be about 5 to 10 degrees below
normal for this time of year, but this will be about 10 degrees
warmer than temperatures today.

As we go through Sunday, an upper-level trough across much of
eastern Canada amplifies southward. The associated cold front is
expected to cross our region late Sunday into Sunday night.
Despite the weak southerly/southwesterly return flow Saturday
into Sunday, moisture will likely be limited. There is a 20 to
30% chance for light snow with the frontal passage, primarily
across East Central PA and northern NJ.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
The two key messages in the long term are the potential for much
colder than normal temperatures Monday into Tuesday, and the
next low pressure system approaching our region Wednesday into
Thursday.

In the wake of the cold front, temperatures, especially Monday
and Monday Night, will be well below normal, as much as 20
degrees below normal. For now, have stayed pretty close to the
blend of models. However, there are some factors suggesting that
guidance could have a warm bias on Monday night/Tuesday morning.
During that time, the surface high will be very close to our
region, with clear skies (at least to start the night) and very
light winds. These types of efficient radiational cooling
patterns tend to end up colder than the median blend of
guidance. However, some guidance suggests that clouds could
start to build in as early as the pre-dawn hours on Tuesday
Morning, which could limit or cut short the radiational
cooling. While it doesn`t look like we will be getting close to
any record lows, in some areas our current forecast is only 5 to
10 degrees away from Cold Weather Advisory criteria.

For Wednesday and Thursday...The eastern Canadian upper-level low
looks to reposition itself as an additional shortwave trough
digs southeastward on its western and southern flank. This
would tend to support low pressure at the surface in the Midwest
and Great Lakes Wednesday which then moves our way into
Thursday. There remains uncertainty with this given all the
moving pieces within the parent upper-level trough, therefore
did not deviate from the blend of guidance. PoPs, especially
with the Wednesday night period are higher with the latest
guidance as compared to yesterday, but there remains
considerable uncertainty. While some moderation in the
temperatures are forecast ahead of this feature, below average
values are expected to continue.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through 12Z...VFR with gradual lowering and thickening of clouds.
North winds around 10 kt will gradually veer towards an east-
northeast direction around 5 kt becoming light and variable at
times. Moderate-high confidence overall.

Today...Anticipate VFR conditions to continue through the morning
hours as periods of light snow begin to occur near KMIV/KACY and
perhaps as far north as KILG. Flurries cannot be ruled out as far
north as KPHL and KPNE at times. By midday (~18Z), anticipate
ceilings to begin to lower to MVFR. East-southeast winds around 5-8
kt. Low confidence overall.

Tonight...Anticipate mostly MVFR or IFR ceilings with occasional
visibility restrictions possible. Areas of drizzle or freezing
drizzle possible especially along the I-95 corridor terminals and
KMIV/KACY. Confidence in occurrence is not high, so kept out of TAFs
for now. Winds light and variable to near calm. Low confidence
overall.

Outlook...

Saturday...Becoming VFR once lingering low ceilings dissipate

Saturday Night through Tuesday...Prevailing VFR.

&&

.MARINE...
No marine headlines are in effect through tonight. East-northeast
winds around 10-20 kt are expected to persist through this
afternoon, before settling out of the north around 5-10 kt tonight.
Seas of 2-4 feet.

Periods of light snow expected through mid-morning, before changing
over to light rain for the remainder of the afternoon. Occasional
drizzle may continue into tonight.

Outlook...

Saturday through Sunday...Winds and seas will stay below SCA
criteria.

Sunday Night through Monday...SCA conditions are expected and gale
conditions are possible behind a cold front Sunday Night that will
also bring an abrupt shift to northwesterly winds. There is a 20 to
40% chance that gale force conditions will develop in this period.

Tuesday...Late Tuesday, wind gusts near or above 20 kt are expected,
but we are currently forecasting winds to stay below SCA criteria.

&&

.TIDES/COASTAL FLOODING...
As a result of the Full Moon on December 4th, we are monitoring
for minor tidal flooding during the daytime high tides through
Sunday. This is primarily for the NJ and DE coasts and lower
Delaware Bay. Previous forecast is tracking well, so expect that
the Friday tides will fall short of advisory levels. However, it
does appear that tidal departures will increase slightly
Saturday into Sunday, increasing the chance for minor tidal
flooding especially for the southern New Jersey and Delaware
coasts, including parts of the lower Delaware Bay.

No tidal flooding is expected elsewhere.

&&

.CLIMATE...
As of 3 AM Friday, the only site that has gotten close to a
daily record low so far has been Mount Pocono (thus far getting
as low as 1 F). We will continue to monitor through the morning.

Record Low Temperatures for December 5th...

SITERECORD/YEAR
Allentown (ABE)11/1926
AC Airport (ACY)11/1966
AC Marina (55N)15/1901
Philadelphia (PHL) 13/1886
Wilmington (ILG) 12/1926
Reading (RDG) 12/1926
Trenton (TTN) 10/1926
Mount Pocono (MPO) -2/1971
Georgetown (GED) 14/1966


Another cold night/morning is possible Monday Night into Tuesday
Morning. At this point, we aren`t forecasting to break any
record lows. Below are the record lows for December 9.

SITERECORD/YEAR
Allentown (ABE)      7/2002
AC Airport (ACY)     6/1968
AC Marina (55N)      5/1876
Philadelphia (PHL)   6/1876
Wilmington (ILG)    13/1960
Reading (RDG)        0/1989
Trenton (TTN)       12/2002
Mount Pocono (MPO)  -1/1902
Georgetown (GED)    10/1976

&&

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

&&

$$

SYNOPSIS...Johnson
NEAR TERM...DeSilva
SHORT TERM...Gorse/Johnson
LONG TERM...Gorse/Johnson
AVIATION...DeSilva/Johnson
MARINE...DeSilva/Johnson
TIDES/COASTAL FLOODING...WFO PHI
CLIMATE...WFO PHI