665
FXUS61 KPHI 101146
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
646 AM EST Fri Jan 10 2025

.SYNOPSIS...
Arctic high pressure currently situated over portions of the
Ohio Valley will continue to shift east into our region through
tonight. An area of low pressure currently over the northwestern
Gulf of Mexico will track northeast, exiting off of the Mid-
Atlantic coast Saturday morning. This will bring light snow to
the area for the first half of the weekend. High pressure will
again settle into the region Sunday into Monday. A reinforcing
shot of cold air will arrive Tuesday into Wednesday, and remain
in place through the extended period as a mid-level trough
prevails across the northeastern US.

&&

.NEAR TERM /THROUGH TONIGHT/...
The near term forecast remains on track as high pressure
continues to drift east pushing the gradient out ahead of it.
Winds are continuing to decrease as high pressure takes hold and
will continue to slacken through the day today. With the high
building in for today, quiet but cold weather can be expected.
Highs today will range from the upper 20s to upper 30s. Winds
will be noticeably lighter.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
Heading into Friday night, we still have a system on tap to
affect the area as low pressure tracks northeast from near the
Gulf coast Friday evening and then eventually moves off the
coast of North Carolina by Saturday morning. Snow moves in
southwest to northeast after midnight Friday night and tapers
off by mid- morning (slightly after 7am). Overall, there has
been little change to snowfall totals with this update as this
continues to look like a nuisance snow event. Latest guidance
shows the NAM being more on the aggressive side and then the
ECMWF being too low. The GFS and HRRR seemed more reasonable.
Also of note, the potential for frontogenetic banding across
parts of Delmarva which would help in higher totals compared to
other areas. Now, most of the area will see a dusting to an inch
with slightly higher totals into southern New Jersey
(Cumberland, Cape May, and Atlantic Counties). Beyond this,
Delmarva looks to see 1-2" mainly. Sussex county in Delaware is
the county we have the highest confidence in seeing advisory
criteria snow (40-60%) which has resulted in a Winter Weather
Advisory being issues while other surrounding counties are a bit
lower. Talbot and Caroline counties in Maryland are other
counties where localized totals of 2" or more remains possible
but there is lower confidence with this.

Once the system departs, winds do pick up. A tightening pressure
gradient from the low and a building high pressure system will
increase our winds with gusts into Saturday night upwards of 25 mph
along with lows ranging from the low to mid 20s. Wind chills will be
in the teens for most.

By Sunday, upper-level ridging builds in with high pressure in
control at the surface. This leads to an overall quiet day with
winds decreasing with a more relaxed pressure gradient and
temperatures in the low 30s to low 40s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
An upper-level ridge along with the surface high moves out on
Monday. Beyond this, it is more of an upper-level troughing pattern.
Periods of clouds result but little in the form of precipitation.
Models continue to show any precipitation struggling to make it into
our region for much of next week. Cold conditions will also be
persisting during this timeframe. Noticeable cold air advection
begins Tuesday and the pressure gradient tightens in this timeframe
as well. As a result, cold and at times windy conditions hold
through at least Thursday.

&&

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

Today...VFR. NW winds 10 to 15 kt with gusts up to 20 kt,
diminishing to 5 to 10 kt after 16-18Z. High confidence.

Tonight...MVFR/IFR conditions anticipated with snow moving
through. Best chances for IFR restrictions due to snow will be from
around PHL southward. Light winds around 5 knots or less,
favoring a southwesterly direction. Moderate confidence in
overall pattern, lower confidence in extent of IFR conditions.

Outlook...

Saturday through Saturday Night...Lingering IFR conditions
possible early becoming primarily VFR by the afternoon. Wind
gusts 20-25 kt out of the NW anticipated.

Sunday...VFR. No significant weather.

Monday...VFR. No significant weather.

Tuesday...VFR. West wind gusting to 20 knots.

&&

.MARINE...
A Small Craft Advisory remains in place as winds remain
elevated around 25-30 knots. Winds and seas will continue to
subside during the day today and conditions look to fall below
SCA criteria by midday.

Additionally, abnormally low water, could continue to make
navigation difficult, particularly outside of deep water
channels. As low tide has past for many locations along the
upper Delaware Bay and tidal Delaware Bay though and water
levels are increasing, the current Low Water Advisory for the
upper Delaware Bay and Special Weather Statement for low water
concerns along the tidal Delaware River will be allowed to
expire at 8 AM.

Outlook...

Friday night through Saturday night...

Some snow/rain move over the waters Friday night into Saturday
morning with increasing NW winds as this departs by Saturday
afternoon into Saturday night. At the very least, expect strong
Small Craft Advisory conditions (90 to 100 percent confidence)
with even the potential for Gales (40 to 50 percent confidence).

Sunday into Monday...Winds/seas will be lowering and should be
mainly below Small Craft Advisory levels.

Monday Night into Tuesday...Winds/seas increase with Small Craft
Advisory conditions possible.

&&

.TIDES/COASTAL FLOODING...
Low tide has past for many locations along the upper Delaware
Bay and tidal Delaware Bay and water levels are increasing.
Therefore, the current Low Water Advisory for the upper
Delaware Bay and Special Weather Statement for low water
concerns along the tidal Delaware River will be allowed to
expire at 8 AM.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...Winter Weather Advisory from 10 PM this evening to 1 PM EST
     Saturday for DEZ003-004.
MD...None.
MARINE...Low Water Advisory until 8 AM EST this morning for ANZ430.
     Small Craft Advisory until 9 AM EST this morning for ANZ430.
     Small Craft Advisory until 11 AM EST this morning for ANZ431-
     450>455.

&&

$$

SYNOPSIS...Guzzo
NEAR TERM...AKL
SHORT TERM...Guzzo
LONG TERM...Guzzo
AVIATION...AKL/Guzzo
MARINE...AKL/Guzzo
TIDES/COASTAL FLOODING...AKL