385
FXUS61 KLWX 041443
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
943 AM EST Wed Mar 4 2026

.WHAT HAS CHANGED...
Patchy dense fog is possible this morning, especially in
northeastern Maryland. The frontal temperature gradient has
been a little better defined through Friday but remains highly
uncertain.

&&

.KEY MESSAGES...
- 1) A meandering front will bring highly variable
  temperatures, occasional rain/storm chances, and nighttime fog
  through Friday.

- 2) A weak cold front arrives late Saturday and slowly pushes
  through by Sunday night before stalling nearby early next
  week.

&&

.DISCUSSION...
KEY MESSAGE 1..A meandering front will bring highly variable
temperatures, occasional rain/storm chances, and nighttime fog
through Friday.

Not too much change, in the mid and late week period as a front
continues to hopscotch across the region. The front has settled just
south of Dover, DE back west toward Washington DC and northwest
along the Potomac River into far western MD. Areas north of the
boundary remain in the 30s and 40s while locations to the south have
warmed into the upper 40s and low 50s. Scattered showers have also
been observed along the front, mainly over central/northeast MD and
across the northern Shenandoah Valley due to in-situ wedging. As of
935am, the bulk of this activity has ended with low and mid level
clouds north of the front and breaks of sunshine to the south.

Expect this trend to continue as the front meanders slowly back to
the south this afternoon and evening as weak high pressure passes
north of the region. Meanwhile, an additional wave of showers is
ejecting out of central WV and southeast OH this morning. This
activity will likely weaken/decrease in coverage as it pushes over
the Alleghenies given blocked westerly flow. With that said, expect
continued on and off scattered shower chances throughout the day,
especially over northern and western portions of the forecast area
(i.e along and north of I-66/US-50 and west of I-81). A few elevated
rumbles of thunder cannot be ruled out over the Allegheny Highlands
this afternoon given weak instability overhead. Shower chances will
continue into the overnight, mainly north of I-66/US-50 and along
the PA/MD line as the front lifts back north. This is attributed to
a secondary area of surface high pressure to the south and ridging
aloft. With the stalled front nearby, expect additional low clouds
and areas of fog given the added moisture over the region.

The placement of waffling front will dictate the overall
temperatures today.There is high confidence for temps in the upper
40s and low 50s over northern/central MD with lower confidence for
low to mid 50s (perhaps upper 50s) along the immediate boundary near
the Potomac River. High confidence remains for low to mid 60s and
even a few upper 60s across the central VA Piedmont/Shenandaoh
Valley given the proximity to the front along with added sunshine for
a longer period of time. Lows tonight will fall back into the 40s
and 50s.

Surface high pressure/upper level ridging build in from the
southeast U.S Thursday as a shortwave trough/low pressure system
move from the mid-MS River Valley into the Great Lakes region. This
will shunt the front back to the north allowing for a bot more
scrubbing of the residual cool air wedge east of the mountains.
06z/12 hi-res guidance continue to struggle a bit in regards to the
placement of the front and to how much cool air is scoured away
given light and variable winds. Once again it looks as if
northeast/central MD will remain the coolest with warmer conditions
south/west into the Shenandoah Valley. Highs will range from the low
to mid 50s north/east of Baltimore to low/mid 70s across the
Shenandoah Valley/central VA Piedmont where more sunshine will
prevail. Any shower chances will remain north of I-70 with some
thunderstorm activity across the Alleghenies/Potomac Highlands late
Thursday afternoon and evening as shortwave energy passes through.

As the low passes off the Mid Atlantic coast Thursday night, high
pressure moving toward the Canadian Maritimes will likely shove the
front back southward, which could result in the reemergence of low
clouds, fog, and cooler temperatures. There is very high spread in
model forecast temperatures on Friday as the front will separate an
increasingly warm airmass building northward from the southeastern
US. A 25-35 degree spread in temperatures could exist from northeast
to southwest. Comparatively, precipitation chances will be lower
Friday and Friday night as ridging aloft builds northward. However,
there still could be some light showers or drizzle near and
northeast of the front.


KEY MESSAGE 2...A weak cold front arrives late Saturday and
slowly pushes through by Sunday night before stalling nearby
early next week.

Saturday may have the best shot at getting the unseasonably warm
airmass across most of the forecast area as a stronger southerly
gradient develops between high pressure off the southeast coast
and low pressure moving through the Great Lakes.

By Saturday afternoon or evening, a weakening cold front will
be dropping towards our region from the northwest. This front
will bring continued chances for some showers and perhaps
thunderstorms with it, mainly Saturday night. By Sunday, the
front will be slowly drifting south, with highest chance for
rain centered along wherever the boundary decides to setup that
day. Right now, that seems to be in the central VA/southern MD
region. At any rate, the front brings very little change in
terms of sensible weather to the region, and barely even a wind
shift. It will solely act as a forcing mechanism for some
showers into early next week. There is a pretty substantial
amount of volatility when it comes to exact temperature
forecasts at this time. It does look to get above normal, but by
how much has yet to be determined still.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
A wavering front will result in low ceilings, fog, showers, and
shifting wind directions at times through Friday. The position
of the front will be critical for the development of these
phenomena, and forecast confidence is lower than usual.

For this morning, the front has lifted close to MRB and DCA.
Low clouds have scoured out to the south, although some fog has
attempted to form in the cloud breaks. The front will drift back
south today, with a gradient from VFR to IFR ceilings likely
very close to the metro terminals. Occasional showers will also
continue to spread from west to east most of the day and
evening, with some decreasing trend the second half of tonight.
However, IFR to LIFR conditions will likely develop tonight at
all terminals as the front reaches its most southern extent.

Thursday may see improvements to roughly MRB/IAD/DCA, but the
Baltimore terminals may hang on to low ceilings most of the
day. More showers and perhaps even an embedded thunderstorm will
cross the northern terminals during the late afternoon and
evening. The southern extent of low ceilings is much more
uncertain Thursday night through Friday night, although the
highest chances remain across MRB/BWI/MTN. Overall lower rain
chances are forecast Friday.

Rain chances will continue as a cold front will sweep through
the region from west to east late Saturday through Sunday. This
could result in an extended period of sub-VFR conditions as a
result. Also, a slight chance for a thunderstorm exists on
Saturday afternoon. Otherwise, SW winds around 15-20 knots on
Saturday, tapering off to around 10-15 knots by Sunday.

&&

.MARINE...
A front will waver back and forth across the waters through
Friday night. Near and north of the front, dense fog could form
at times during the nighttime/early morning hours.

Over these next three days, the northern Chesapeake may largely
keep east to northeast winds, while areas south of Washington
and Bay Bridge could flip to southerly at times. Winds should
remain below advisory criteria.

Winds will gust to near SCA criteria out of the SW on Saturday.
However, thinking that the continued cold waters in comparison to
warmer air temperatures could confine the threat primarily to the
smaller waterways, with less wind over the open Bay waters. Winds
taper off on Sunday, with SCAs unlikely at this time.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

DISCUSSION...ADS/CJL/EST
AVIATION...ADS/CJL/EST
MARINE...ADS/CJL

NWS LWX Office Area Forecast Discussion