069
FXUS61 KLWX 172023
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
323 PM EST Sat Jan 17 2026

.WHAT HAS CHANGED...
Winter Weather Advisory for today have ended. Portions of the
Small Craft Advisory for today were cancelled early. Confidence
is increasing for snow on Sunday. A Winter Weather Advisory has
been issued for Cecil and Harford Counties. While Sunday night
through Tuesday night are still expected to be cold, wind chill
values have been trending a little warmer.

&&

.KEY MESSAGES...
- 1) A wave of low pressure will bring snow to parts of the area
  Sunday.

- 2) Very cold conditions are expected over the region Monday
  night through Tuesday night, with below normal temperatures
  continuing through the remainder of the week.

&&

.DISCUSSION...
KEY MESSAGE 1...A wave of low pressure will bring snow to parts
of the area Sunday.

Low pressure is located north of Lake Huron this afternoon, with
a cold front trailing into the Ohio Valley. Earlier snow has
departed with breaks of sun occurring across much of the area.
Temperatures are making their way through the 40s to near 50 in
these locations. Some showers ahead of the cold front are
approaching the Allegheny Front. Given marginal temperatures
and brief duration of showers, the earlier Winter Weather
Advisory was canceled. As the front moves into the area tonight,
a period of upslope snow may develop late this evening into the
overnight. At this time, the most likely totals appear to be 2
inches or less, so no additional advisories are planned at this
time.

As the front moves eastward, mid and upper level dynamics will
assist precipitation developing along and behind the boundary.
Low pressure will develop along the frontal zone along the coast
and ride northeastward through the day. This will be a tricky
scenario as snow will be highly dependent on colder air catching
up to the moisture, which is sometimes difficult to achieve and
offset by dry advection. Temperatures will be colder sooner west
of I-95, but these areas will likely see a shorter duration of
precipitation. East of I-95, more precipitation is expected, but
temperatures may be slightly above freezing for a large part of
the event, and precipitation may even be rain for a while. The
best potential for cold air and higher precipitation totals to
overlap appears to be northeastern Maryland. Thus, confidence
was high enough to issue a Winter Weather Advisory for this area
with the greatest potential for 2 inches of snow. However, if
the afternoon wave of precipitation associated with the low
misses to the south and east (which some models show), totals
may fall short. Most other areas will see a slushy coating to an
inch, perhaps locally higher where any banding sets up. Rates
will be important to any sort of accumulations, especially as
the day wears on, given marginal surface temperatures. Will
have to monitor for possible expansions to the advisory,
especially if confidence increases a colder solution near and
east of the I-95 corridor. End time for the precipitation could
be pretty early in the day closer to and west of the Blue Ridge.
How long the precipitation lasts closer to the Chesapeake Bay
will depend on the western extent of the second frontal wave. In
any event, dry conditions look likely by mid Sunday evening.
Temperatures from the mid teens to mid 20s are expected Sunday
night, so any residual moisture or slush could refreeze.

KEY MESSAGE 2...Very cold conditions are expected over the
region Monday night through Tuesday night, with below normal
temperatures continuing through the remainder of the week.

Behind an Arctic front that crosses the region early on Monday
expect very cold conditions to settle in for the start of the week.
Well below normal temperatures are expected through at least
Wednesday, with a slight reprieve on Thursday, then another
reinforcing shot of cold air arrives for Friday.

Highs are going to remain in the 30s to around 40F each day, with
Tuesday being the coldest as the entire area remains below freezing
during the daytime. It will be particularly cold Monday night and
Tuesday night with lows in the single digits to teens. When
factoring in the winds, expect wind chills to be in the single
digits, with around -10F to -15F in the mountains. Again, the
coldest wind chills are forecast for Monday night into Tuesday
morning when a reinforcing upper trough and secondary cold front
cross the area.

By Thursday, the temperatures return to seasonal values of highs in
the 40s and lows in the 20s. At this point in the week model
guidance is some consensus in tracking a cold front across the area
Thursday afternoon/evening. This could bring a slight rain/snow mix
to parts of the area, though precip chances overall are low at 20-30
pct. Cold air surges in behind the front to close the week.

Per the 12Z models and early ensemble guidance the synoptic pattern
could become volatile for next weekend. A northern stream and
southern stream system interact over the central CONUS, eventually
pushing a deepening low pressure system and strong cold front across
the Mid-Atlantic. Few details are certain beyond that, so continue
to monitor the forecast through the upcoming week for what could be
the next possible round of widespread wintry precip next
weekend.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
VFR conditions have returned and will continue until late
tonight. Winds are south to west this afternoon but could be
somewhat light and variable the first half of the night in a
weak pressure pattern. A cold front arriving the second half of
the night will bring more definitive northwest winds as well as
lowering ceilings.

Low pressure passing on the front along the coast will likely
bring a little snow or a rain/snow mix to many of the terminals
Sunday. Some light slushy accums and a period of IFR conditions
in snow and low ceilings are becoming increasingly likely,
though temps will be marginal and the system will be fast-
moving. Lowest chance of precip/IFR is at MRB, with fairly
brief durations at IAD and CHO. Precip may last longer at DCA
and especially BWI/MTN. There are some indications of a midday
break, with additional snow possible at these eastern terminals
in the afternoon. However, the western extent of the second wave
is still very uncertain. N/NW winds may briefly gust to around
15 kt Sunday afternoon and evening as the low pulls away. VFR
conditions should return fairly quickly after precip ends.

VFR conditions are expected Monday through Wednesday behind a strong
arctic front. The main aviation impact will be gusty northwest winds
each day that gust around 20-25 knots. Monday looks to be the
gustiest day, with possible gusts up to 30-35 knots in the
afternoon.

&&

.MARINE...
South to southwest winds only really became gusty on the waters
surrounding southern Maryland, but even these winds are
subsiding. Thus the Small Craft Advisory will be set to expire
at 4 PM. Then, winds are expected to diminish into the evening in
a weak pressure pattern ahead of a cold front.

Lighter northwest winds are anticipated in the wake of the front
late tonight, with a slight uptick possible for a time Sunday
afternoon and evening as low pressure passes offshore. Marginal
advisory conditions are possible during this time. This low is
also expected to bring light snow or a rain/snow mix, which
will reduce visibility over the waters on Sunday.

SCA conditions are likely for MLK Day into Tuesday behind a
strong arctic front. Northwest winds gust between 20-25 knots
across all the waters, with gusts up to 30 knots possible Monday
afternoon. Winds remain at SCA levels Monday night through
Tuesday afternoon, then decrease below SCA levels Tuesday night.
Another round of SCA conditions is possible Wednesday
afternoon. Freezing temperatures could result in ice buildup on
the local waters, especially in the small tributaries.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for
     MDZ008-507-508.
VA...None.
WV...None.
MARINE...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for
     ANZ530.
     Small Craft Advisory until 4 PM EST this afternoon for
     ANZ532>534-536-537-540>543.

&&

$$

DISCUSSION...ADS/KRR
AVIATION...ADS/KRR
MARINE...ADS/KRR

NWS LWX Office Area Forecast Discussion