980
FXUS61 KLWX 071519
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1019 AM EST Sun Dec 7 2025

.SYNOPSIS...
High pressure remains nearby this afternoon with continued cool
temperatures. A cold front will cross the area this evening
with an upper level low pressure system passing to the south
late tonight into Monday. Both of these systems could bring some
light snow showers to the mountains and to the I-64 corridor.
Brief high pressure builds again Tuesday before another area of
low pressure and series of fronts cross the area during the
middle to latter portions of the week. This brings renewed cold
air to the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Freezing Fog Advisory remains in effect until Noon today.
Impacts so far have been somewhat mute although slick spots are
likely on elevated and untreated surfaces. Visibilities remain
down around a 1/4 mile from DCA Airport down to Charlottesville
and back toward Richmond. Expect fog to burn off between 11am-
Noon with partly to mostly cloudy skies expected through this
afternoon. Highs this afternoon will push back into the upper
30s and mid 40s outside the mountains. Lows tonight will fall
into the teens and 20s in the wake of the Arctic frontal
boundary. (See previous discussion)

Cloud cover will gradually return this evening as weak high
pressure departs the region and a Arctic cold front approaches
from the Great Lakes/Ohio River Valley. This front will usher in
a much colder airmass for the start of the new workweek. Winds
also pick up overnight behind the cold front with northerly
gusts to around 15 to 25 mph. The driver of this system is a
shortwave aloft which is slated to move through New England
later this evening. With the forcing displaced off to the north,
any upslope showers should be brief and of low impact to the
Alleghenies. Total snow amounts will likely be around a coating
to perhaps a half inch in spots.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Previous discussion...
The mentioned system crossing the Tennessee Valley reaches the
Carolinas by midday Monday. Ample ascent ahead of this wave
will have access to a cold post- frontal air mass. As such, snow
should be the dominant precipitation type as the system sweeps
across southern Virginia. The northern extent of this
precipitation shield is uncertain. A preponderance of the models
cut things off in the vicinity of I-64 while extending back
into the Potomac Highlands. However, occasional high- resolution
models attempt to lift this axis toward I-66. For now, will cap
the northern extent of accumulations around I-64 with around a
half inch to inch possible. Given cold temperatures, much of
this should stick on untreated surfaces.

Relative to the previous day, Monday is likely to be much colder
in the wake of the frontal passage. Forecast highs will mainly
range from the upper 20s to mid 30s, with upper teens to mid 20s
in the mountains. This is accompanied by north-northeasterly
gusts to around 20 to 25 mph underneath mostly cloudy skies. Any
light snow should exit the local area by just after dark.

A strong dome of Canadian high pressure builds in from the Great
Lakes on Monday evening/night. This will set the stages for a
cold night across the region. Northerly winds are forecast to
diminish in strength into the night setting the stages for ample
radiational cooling. The latest forecast package calls for
widespread lows between 10 to 15 degrees, with upper teens to
low 20s along and east of I-95. A bit of lingering wind will
lower wind chills to near 0 degrees across the mountains.

Within the active northwesterly cyclonic flow regime, an
additional shortwave races across the Great Lakes and Mid-
Atlantic region on Tuesday. Moisture is rather scant so the only
real impact is an increase in cloud cover. Underneath this mix
of clouds and sun, the forecast remains chilly with highs in
the 30s to low 40s (mountains in the upper 20s to mid 30s).
Despite a shift to southerly winds on Tuesday, temperatures do
not rise much as 1000-500 dm thicknesses only rise by around 5
dm over a 24-hour period.

As high pressure exits offshore Tuesday evening, some warm
advection precipitation begins to unfold over western Maryland
on Tuesday night. This likely comes in the form of a rain/snow
mix depending on temperatures. Area-wide overnight temperatures
will be in the mid 20s to low 30s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Broad upper level trough with numerous reinforcing shortwave-troughs
is expected to dominate the flow across the eastern CONUS during the
middle and second half of next week. The first of a series of low
pressure systems will move across the eastern Great Lks Wednesday
and bring the risk of rain and snow showers to the Appalachian
region and northern MD, turning into snow showers in the mountains
Wed afternoon and evening. The snow shower activity will continue
over the mountains into Thu morning where several inches of
accumulation may occur.

A second area of low pressure is expected to track from the TN River
Valley and across North Carolina late Thu night into Fri and may
bring some light snows to the local area and maybe rain across
central Virginia. This will be another fast moving system similar to
the one Friday morning. Much colder air will follow behind this
system for Fri night into Sat with 850 mb temps fcst to plummet to -
15C and daytime highs struggling to reach 30F.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
A Freezing Fog Advisory remains in effect until Noon today. The
terminals more closely impacted are CHO and DCA. The main
threat of more pronounced (IFR/ LIFR) restrictions have been to
the south and east. This fog will give way to a mix of clouds
and sun with light southerly winds.

An upstream cold front arrives later this evening which yields
a shift to north to northwesterly winds late tonight. Gusts
increase just ahead of daybreak while continuing through much of
Monday. Afternoon gusts could reach 20 to 25 knots, perhaps
higher at times during peak vertical mixing. VFR conditions are
expected on Monday, but some sub-VFR conditions are possible at
KCHO as light snow tracks near I-64.

Winds turn light on Monday night as Canadian high pressure
builds to the north. As this anticyclone exits offshore, a
return southerly flow ensues for Tuesday with afternoon gusts
to around 15 to 20 knots. VFR conditions continue in advance of
the next weather maker arriving by mid-week.

VFR conditions Wed with a risk of rain showers, mainly northern
terminals. Light snow possible late Thu night into Fri, possibly
rain at CHO. Shifting winds Wed night with a frontal passage.

&&

.MARINE...
Winds remain on the lighter side owing to high pressure over
the waters, a cold front tracks through late this evening
yielding gustier winds in the wake. Expect a shift to northerly
winds late tonight while turning more north-northeasterly on
Monday. Gusts up to 20 to 30 knots are looking likely during
this period. Small Craft Advisories will be required during this
period which may even include occasional gales over the
southern waters. Winds diminish into Monday night as Canadian
high pressure builds to the north. Another ramp up is likely by
Tuesday evening/night given southerly channeling effects. Small
Craft Advisories will again be needed.

SCA conditions Wed into Thu and again Fri.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Freezing Fog Advisory until noon EST today for DCZ001.
MD...Small Craft Advisory from 1 AM to 6 PM EST Monday for MDZ008.
     Freezing Fog Advisory until noon EST today for MDZ013-016>018.
VA...Freezing Fog Advisory until noon EST today for VAZ036>039-050-
     051-053>057-502-527.
WV...None.
MARINE...Small Craft Advisory from 1 AM to 6 PM EST Monday for
     ANZ530>533-538>542.
     Small Craft Advisory from 3 AM to 6 PM EST Monday for
     ANZ534>537-543.

&&

$$

SYNOPSIS...BRO
NEAR TERM...BRO/KLW
SHORT TERM...BRO
LONG TERM...LFR
AVIATION...LFR/KLW
MARINE...LFR/KLW