Warminster, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

424
FXUS61 KPHI 241428
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
928 AM EST Sat Jan 24 2026

.WHAT HAS CHANGED...
Cold Weather Advisory and Extreme Cold Warning extended until
Noon today for the entire area. Small Craft Advisory and
Freezing Spray Advisory for Delaware Bay and the adjacent
Delaware Atlantic coastal waters extended until 1 PM today.

&&

.KEY MESSAGES...
1. Dangerous cold continues through this morning with wind chills
below zero for most. Wind chills as low as -20F expected to
continue in the Poconos.

2. A major winter storm is expected to impact the area, beginning
tonight and continuing through Monday Morning. This storm will bring
significant snow and ice accumulations to the entire area, resulting
in major disruptions.

3. Arctic air remains in place through the upcoming week with
temperatures below freezing into Friday.

&&

.DISCUSSION...
KEY MESSAGE 1...Dangerous cold continues through this morning with
wind chills below zero for most. Wind chills as low as -20F
expected to continue in the Poconos.

In the wake of a strong arctic front, very cold temperatures have
settled over the area. A notable breeze in combination with
frigid air temperatures are resulting in widespread below zero
wind chills this morning. As a result, the Cold Weather Advisory
and Extreme Cold Warning have been extended until Noon today.

Ahead of the storm, it will be bitterly cold today, with highs only
topping out in the upper teens/low 20s. The Poconos may not even
make it out of the single digits.


KEY MESSAGE 2... A major winter storm is expected to impact the
area, beginning tonight and continuing through Monday Morning. This
storm will bring significant snow and ice accumulations to the
entire area, resulting in major disruptions.

A significant winter storm finally gets to our area, beginning
tonight. Snowfall begins after 1 AM from southwest to northeast
as low pressure approaches from the southwest. As snow spreads
into the region, a secondary area of low pressure begins to form
near the Outer Banks, moving up the coast as Sunday goes on.
The track of this secondary low looks to be inside the benchmark
(40 N, 70 W), which usually results in a mixed precipitation
storm for our area and a forecasting headache. That is the case
here. However, confidence is increasing in this forecast.

The main changes from the daytime package were cutting snow totals
south and east of I-95 as the trend has been a touch west with the
track of the low, resulting in more of a sleet/freezing rain mix and
even plain rain along the coast. Snow totals were slightly reduced
for other areas as well, but not by much. VERY IMPORTANT to stress
that while snowfall totals have been reduced slightly, the impacts
remain the same. The combination of snow, sleet, and freezing rain
will result in MAJOR impacts and that thinking has not changed for
days now.

Snowfall envelops the whole region by daybreak Sunday. An area of
strong mid-level frontogenesis will lift northward as the morning
goes on, and all areas should see a very good thump of snow before a
changeover to sleet or freezing rain. Snowfall rates over 1" per
hour are likely (60-80%), mainly for New Jersey and Pennsylvania
tomorrow morning into the early afternoon, with even a low chance
(20%) for rates over 2" per hour. As the day progresses, a warm nose
aloft moves in from the southeast. After looking at some model
soundings, currently thinking the mix line gets right to about
Reading and Allentown in PA and right up to I-78 in NJ. Snowfall
amounts will be dependent on how fast or slow that warm air
advection aloft is. Given how good the NAM is in these cases, the
forecast generally relies on that temperature profile, but not as
aggressive, with the thinking that the impressive rates before the
changeover can hold back the warm nose aloft. It will be very
interesting to see how this plays out tomorrow morning. Important to
note that guidance generally underestimated the strength of the cold
airmass this morning. Does it matter? That is the question that will
be figured out via mesoanalysis as the event begins.

At onset, snow ratios will be around 15-18:1, decreasing to around 7-
10:1 by the early afternoon (and even lower where sleet begins) as
warmer air aloft moves in. This will result in a fluffy snow
texture. However, add in sleet and/or measurable ice on top of that?
It could be very difficult to remove from roads, driveways, and
sidewalks. This is mainly why we are stressing major impacts,
regardless of snow totals. There is high confidence in at least 6"
of snow, and sleet/ice on top of that will just exacerbate impacts
(and most areas are highly probable to see more than 6").

In terms of specific amounts, the forecast has 12-16" with localized
amounts up to 18" for the I-78 corridor on north. These areas should
primarily stay snow. From New Castle County, DE out to LBI and
points north up to the I-78 corridor, amounts of 8-12" are expected
with a prolonged period of mixing occurring. South of that line, 4-
8" are expected and most locations in this zone likely even see some
plain rain.

With a frigid cold airmass overhead and a strong push of warm air
aloft, there is a growing threat for freezing rain and ice
accumulation. The corridor of highest amounts has shifted southeast
a bit, with the current forecast having a stripe of 0.25"-0.4" over
the Eastern Shore, extending into central DE, and continuing into
Cumberland/Salem/Gloucester/and part of Camden County in NJ. The I-
95 corridor, once the focus of the higher amounts, has trended down
a bit, though still somewhat significant - around a tenth to two
tenths of an inch of ice. The question is going to be what the depth
of the warm nose is. If it is thinner, expect more sleet. If it is
deeper, then more freezing rain and ice is likely. There is higher
confidence in the highest amounts landing somewhere between the I-95
corridor and Garden State Parkway in central and southern NJ and
then somewhere over central and northern Delmarva. These ice
accumulations come AFTER anywhere from 4-8/8-12" of snow fall. This
will only heighten the impacts, regardless of exactly how much
falls.

Overall, no changes to the Winter Storm Warning, which is in place
tonight through Monday morning. Snow tapers off by Midday Monday,
transitioning to a prolonged stretch of very cold temperatures.

KEY MESSAGE 3...Arctic air remains in place through the upcoming
week with temperatures below freezing into Friday.

Arctic high pressure will then be in control for the rest of
next week, with Monday possibly being the mildest day, that term
is used loosely, with highs in the upper 20s to low 30s. A strong
cold front is forecast to cross through Monday night, and then lows
will crash into the single digits. The strong winds developing
over the area Monday night into Tuesday morning will create
widespread wind chills will be as low as 10 below, with wind chills
as low as 20 below in the southern Poconos. Cold Weather Advisories
and Warnings will likely be needed. Highs will be in the teens and
low 20s Tuesday, with highs not much warmer than that through
Friday. Lows will be in the single digits.

As a result of this prolonged cold, do not expect the new
snowpack to melt much.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...

Today... VFR with high level clouds. North-northwest winds 10-15
knots with some gusts to 20 knots this morning, decreasing to
near 10 knots this afternoon. High confidence.

Tonight... VFR thru 06Z all sites then VSBY/CIG restrictions towards
dawn as snow overspreads all areas late. IFR/LIFR quickly
realized as snow begins. Northeasterly winds around 5 knots.
Moderate confidence.

Outlook...

Sunday/Sunday night... Widespread LIFR conditions with snow, sleet
and freezing rain expected much of the time. Snow will predominate
Sunday morning with ice/sleet mixing in from South/West to
North/East thru the afternoon. Precip may change to all rain KACY
during the evening Sunday. East to Northeast winds 10 to 15 kts. Low
confid with regards to p-type/timing.

Monday... Lower conditions early then improvement back to VFR by
afternoon.

Tue thru Wed... VFR much of the time.

&&

.MARINE...
A Small Craft Advisory and Freezing Spray Advisory are now in
place through 1 PM today. Wind gusts out of the northwest 25-30
knots, diminishing later this morning and this afternoon with 3
to 6 foot seas.

A period of sub-SCA conditions comes for the afternoon and
overnight hours with north/northeast winds around 10-20 kt and
seas 2 to 4 feet. Snow moves over the marine zones as the night
goes on, likely reducing visibility.

Outlook...

Sunday...A Gale Watch is in effect for all marine zones. Winds out
of the east/northeast could get near 35 kt at times, especially over
the ocean. Seas of 6 to 9 feet.

Sunday Night through Monday Night...SCA conditions expected with
gales possible (40-50%). Seas 6 to 9 feet and winds 20-30 kt,
out of the east/northeast on Sunday Night and northwest on
Monday.

Tuesday...SCA conditions and freezing spray possible.

Wednesday...Sub-SCA conditions.

&&

.CLIMATE...
An impactful winter storm bringing significant snow
accumulations to the area is expected on Sunday. Here are the
1-day daily record totals for January 25th from our snow
observing sites. Some of these could be challenged.

January 25th Daily Snowfall Records

Allentown (ABE)       10.4" (1988)
AC Airport (ACY)      8.3"  (2000)
Philadelphia (PHL)    8.5"  (2000)
Reading (RDG)         9.0"  (1905)
Trenton (TTN)         14.0" (1905)
Wilmington (ILG)      10.0" (2000)

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Cold Weather Advisory until noon EST today for PAZ060>062-070-
     071-101>106.
     Winter Storm Warning from 7 PM this evening to 1 PM EST Monday
     for PAZ060-070-071-101>106.
     Winter Storm Warning from 1 AM Sunday to 1 PM EST Monday for
     PAZ054-055-061-062.
     Extreme Cold Warning until noon EST today for PAZ054-055.
NJ...Cold Weather Advisory until noon EST today for NJZ001-007>010-
     012>027.
     Winter Storm Warning from 7 PM this evening to 1 PM EST Monday
     for NJZ008>010-012>021-026-027.
     Winter Storm Warning from 7 PM this evening to 7 AM EST Monday
     for NJZ022>025.
     Winter Storm Warning from 1 AM Sunday to 1 PM EST Monday for
     NJZ001-007.
DE...Cold Weather Advisory until noon EST today for DEZ001>004.
     Winter Storm Warning from 7 PM this evening to 1 PM EST Monday
     for DEZ001-002.
     Winter Storm Warning from 7 PM this evening to 7 AM EST Monday
     for DEZ003-004.
MD...Cold Weather Advisory until noon EST today for MDZ012-015-019-
     020.
     Winter Storm Warning from 7 PM this evening to 1 PM EST Monday
     for MDZ012-015-019-020.
MARINE...Small Craft Advisory until 1 PM EST this afternoon for ANZ430-
     431-450>455.
     Freezing Spray Advisory until 1 PM EST this afternoon for
     ANZ430-431-450>455.
     Gale Watch from Sunday morning through Sunday afternoon for
     ANZ430-431.
     Gale Watch from Sunday morning through Sunday evening for
     ANZ450-451.
     Gale Watch from Sunday morning through Sunday afternoon for
     ANZ452>455.

&&

$$

DISCUSSION...Gorse/Hoeflich/OHara
AVIATION...Gorse/OHara
MARINE...Gorse/Hoeflich