905
FXUS61 KLWX 191615
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1115 AM EST Sun Jan 19 2025

.SYNOPSIS...
Low pressure across the Southeast will gather strength as it passes
south of the area this afternoon ahead of a slowly advancing Arctic
front. Arctic high pressure will follow for much of the week as one
or more waves of low pressure develop to the south.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 16Z/11AM EST, precipitation continued to expand across
the Mid-Atlantic. A tight gradient in air temps had developed
from roughly Norrisville MD southwest to Wintergreen VA. NW of
this line, temps were roughly 31-33F with mainly snow (light
accums observed); SE of this line was in the mid to upper 30s
with a mix of rain, sleet, and snow (little to no accums yet).
Over the Appalachians, bands of moderate to heavy snow had
developed dropping visibility to less than half a mile; temps
over the higher terrain in these areas were in the 20s. Freezing
levels were continuing to drop per recent ACARS as well as
dual-pol data from KLWX. KPBZ/KFCX radars shows moderate to
heavy snow banding pivoting E/SE toward eastern WV/western MD.

Colder temps/bands of heavier precip are expected to press E/SE
through the day, eventually reaching the metros by 2-3PM.

Will continue to closely monitor temp/ptype trends, and where
heavier bands set up, and refine the forecast as necessary
through the day. Stay tuned to weather.gov/lwx/winter for the
latest updates.

Once the front pushes offshore this evening, low pressure will
pull away toward New England and much colder air will rush into
the region on gusty NW winds. This will cause temps to fall
steadily overnight, reaching the teens to around 20 for most
(with single digits over the higher elevations). Winds combined
with the cold will result in wind chills in the single digits to
lower teens east of the mountains (-10 to -20 for the mountains).

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The main highlight of this period will be the very cold
temperatures combined with the brisk winds to create dangerously
cold wind chills.

Models are now indicating light snow developing ahead of main
central CONUS trof Tue afternoon and evening while precip
associated with Southeast U.S. coastal storm remains far south
of the area, potentially only affecting far southern MD in the
worst case scenarios. Have introduced some PoPs for Tue
afternoon and evening.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Cold air continues to envelope the region Wednesday with a broad
upper trough encompassing most of the CONUS and high pressure
building in at the surface. High temperatures are expected to top
out in the teens to mid-20s outside of the mountains, with single
digits in the mountains. Low temperatures will range from near to
just below zero in the mountains to near +10 in far southern
Maryland. While winds are expected to lighten as high pressure
builds in, it won`t take much to bring apparent temperatures to near
or just below zero early Wednesday morning for much of the area.
Apparent temps along the Alleghenies could even approach/exceed the -
20 mark with continuing NW gustiness Wednesday morning. An Extreme
Cold Watch is in effect through Thursday morning for the Alleghenies
given the high confidence in dangerous wind chills this far out.

While the cold is the main story, there is also the potential for
snow into Wednesday morning, but there remains uncertainty regarding
the track of a progressive low just to our south. Recent guidance
has trended south and east of our area, resulting in lower snow
probs. As of now, the most likely areas to receive any snow would be
far southern Maryland. Another shot of quick snow is possible
Thursday into Friday as an embedded shortwave swings through, with
similar uncertainties and a larger spread. However, later in the
extended would appear more favorable with more available moisture.
Temperatures are expected to warm into the 30s (mountains 20s) by
Thursday and Friday.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Precip continued to break out across the region as of 16Z/11AM
EST. Ptype was generally -RAPLSN, with RA the main ptype at
DCA/IAD/CHO/MTN, PLSN at BWI, and SN at MRB. Will AMD as
necessary as ptype and intensity trends are realized through the
day. Overall, anticipate -RAPL transitioning to SN (heavy at
times) 17Z-20Z. Calm/light north flow will increase then shift
to NW later this afternoon into this evening, gusting to around
25 kts tonight. Gusty NW flow and VFR will persist tonight
through Tuesday. Of note, a notable winter storm will be passing
across the southern U.S. early this week; most of this should
stay south of the local area, but some light precip (in the form
of snow) is possible Tuesday PM on its northern edge as the
parent upper trough swings by. Given the very cold temps and
gusty winds, wind chills may fall to around 0 at times over the
next few days beginning tonight; any lingering moisture will
freeze, as well.

VFR conditions are expected Wednesday and Thursday as high pressure
builds into the region. W/NW winds on Wednesday become southerly on
Thursday. A low pressure system may pass to our near south late
Thursday into Friday, but there is still uncertainty regarding the
track. Temperature wise, expect highs in the upper teens/low 20s
Wednesday warming into the upper 20s and low 30s on Thursday. Lows
will be in the teens and single digits.

&&

.MARINE...
Light north winds will increase and turn northwest by tonight as
low pressure passes to the south, then moves up the coast and
strengthens. Gusts to near gale force are possible overnight
into Monday, but otherwise solid SCA conditions are expected
with freezing spray at times as very cold temperatures move in.
A mix of rain, sleet, and snow will transition to all snow this
afternoon before ending this evening. Additional light snow is
possible, especially over the waters surrounding southern
Maryland late Tuesday.

SCA conditions could continue through Wednesday. Winds are then
expected to diminish overnight and become light and southerly on
Thursday. Freezing spray remains a concern through Wednesday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Winter Weather Advisory until 7 PM EST this evening for DCZ001.
MD...Winter Weather Advisory until 7 PM EST this evening for MDZ008-
     011-013-014-504-506-508.
     Winter Storm Warning until 9 AM EST Monday for MDZ001.
     Extreme Cold Warning from 4 AM Monday to 7 AM EST Thursday for
     MDZ001-501.
     Winter Storm Warning until 7 PM EST this evening for
     MDZ003>006-501>503-505-507.
     Cold Weather Advisory from 4 AM Monday to 1 PM EST Tuesday for
     MDZ003-502.
VA...Winter Weather Advisory until 7 PM EST this evening for VAZ025-
     026-029-038>040-051-053-054-501-502-504-506-508-526-527.
     Extreme Cold Warning from 4 AM Monday to 7 AM EST Thursday for
     VAZ503.
     Winter Storm Warning until 7 PM EST this evening for VAZ027-
     028-030-031-503-505-507.
     Cold Weather Advisory from 4 AM Monday to 1 PM EST Tuesday for
     VAZ025>031.
     Extreme Cold Warning from 4 AM Monday to 1 PM EST Tuesday for
     VAZ504-507-508.
WV...Winter Storm Warning until 9 AM EST Monday for WVZ501-505.
     Extreme Cold Warning from 4 AM Monday to 7 AM EST Thursday for
     WVZ501-503-505.
     Winter Storm Warning until 7 PM EST this evening for
     WVZ050>053-055-502>504-506.
     Cold Weather Advisory from 4 AM Monday to 1 PM EST Tuesday for
     WVZ050>053-055-502-504.
     Extreme Cold Warning from 4 AM Monday to 1 PM EST Tuesday for
     WVZ506.
MARINE...Winter Weather Advisory until 7 PM EST this evening for ANZ530.
     Small Craft Advisory until 6 PM EST Monday for ANZ530>543.

&&

$$

SYNOPSIS...DHOF
NEAR TERM...DHOF
SHORT TERM...LFR
LONG TERM...CAS
AVIATION...DHOF/CAS
MARINE...DHOF/CAS