Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

203
FXUS61 KLWX 190800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Sun Jul 19 2026

.WHAT HAS CHANGED...
Minimal changes to the forecast. Tuesday could present a
localized flash flood threat in addition to the severe
thunderstorm threat.

&&

.KEY MESSAGES...
- 1) Thunderstorm chances may linger across southern portions of
  the area as a front stalls to the south today and Monday.

- 2) A strong cold front brings the potential for severe
  thunderstorms and localized flash flooding Tuesday, possibly
  lingering into Wednesday depending on the front`s progress.

&&

.DISCUSSION...
KEY MESSAGE 1...Thunderstorm chances may linger across southern
portions of the area as a front stalls to the south today and
Monday.

A cold front will continue to ease southward through the area
this morning. Several corridors of isolated to scattered showers
have formed in the broader frontal zone as a shortwave trough
approaches. While models are struggling with the specific
coverage, showers will remain possible through mid morning or so
(shifting south with time), when the trough departs and deeper
moisture pushes south.

It does appear that the wind shift will make it through a large
part of the area by this afternoon, but there will be some
lingering convergence and moisture near and south of I-64 in
central Virginia as a wave of low pressure passes to the south.
Most guidance shows scattered showers and thunderstorms
developing in this corridor through the afternoon before
drifting south. Since greater instability will be south of the
forecast area and shear is modest, the severe weather threat is
limited.

The front will stall out near North Carolina tonight and Monday as
high pressure crosses the northern Mid Atlantic. This high will
depart to the east by Monday evening, with return flow at 850mb
beginning a bit earlier. This will allow moisture, and
eventually the front, to return northward. Any rain risk will
likely remain limited to the southern tier of the CWA Monday
afternoon. Stronger moisture return Monday night could result in
some showers and thunderstorms spreading northward with time.

Near to below normal temperatures can be expected in the wake of
the front, with the largest negative anomaly tonight into
Monday.


KEY MESSAGE 2...A strong cold front brings the potential for
severe thunderstorms and localized flash flooding Tuesday,
possibly lingering into Wednesday depending on the front`s
progress.

A strong upper trough and cold front will cross the region
Tuesday into Wednesday. A secondary cold front may follow the
first front sometime midday Wednesday into the afternoon.
There`s still some uncertainty with how Tuesday unfolds as there
could be ongoing showers and thunderstorms in the warm advection
regime that limits heating. In addition, the trough and front
will likely remain northwest of the area through peak heating.
However, height falls, prefrontal troughing, and the terrain
will provide a lifting mechanism. Even though instability may
not become too large, there will be increasing wind fields ahead
of the trough. Damaging winds will likely be the primary threat
with storms, although other hazards cannot be ruled out pending
the placement of the trough and ingredients at play. A flash
flood threat may also develop as precipitable water increases
above 2 inches and a low level jet develops that may be nearly
parallel to storm motions and the approaching front. Both
threats may linger after sunset as the best forcing (and
possibly existing organized convection) arrives from the
northwest.

More uncertainty exists for Wednesday due to the timing and
placement of the secondary front and trough axis. Strong wind
fields will remain in place, so a severe weather threat could
linger east of this front. At this time, the greatest potential,
should it occur, would be east of the Blue Ridge Mountains.

Longwave troughing remains over the eastern US for the end of
the week. The front will remain south of the area (though how
far south is in question) as high pressure builds to the north.
The main story will be below normal temperatures and lower
humidity. While dry weather is most likely, uncertainty in more
subtle synoptic forcing features increases toward the end of
the week.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
A cold front moves south across the area this morning,
eventually shifting winds to the northwest. While an isolated
shower is possible, any impacts would be brief. Some guidance
also shows a brief period of MVFR ceilings, but confidence
remains too low to include in the TAF.

The front will be close enough by that some showers and
thunderstorms may form near CHO this afternoon. Have a PROB30
for now given uncertainty in coverage.

Prevailing VFR conditions are expected Monday with winds
becoming E to SE. The front will work back northward Monday
night, which could result in sub-VFR ceilings and a chance of
showers and thunderstorms.

Showers and thunderstorms could push through multiple times
Tuesday into Wednesday. Severe weather is possible. Gusty south
winds are expected Tuesday and Wednesday, becoming northwesterly
behind the associated cold front.

&&

.MARINE...
Marginal SCA in westerly winds for the wider mid bay waters
through sunrise. As a cold front pushes through, there may be a
few northwesterly gusts of 15-20 kt through the day, but
expected coverage and duration doesn`t warrant an SCA at this
time.

Expect sub-SCA level conditions Sunday night into Monday as high
pressure builds to the north. Southerly channeling may increase
winds by Monday night, with an advisory possible for the bay.

SCA conditions due strong southerly flow are expected Tuesday
into Wednesday as a storm system and two possible fronts push
across the region. Strong to severe thunderstorms are possible
both days as well. Behind the cold front, SCAs in NW flow are
likely Wednesday night into possibly Thursday.

&&

.TIDES/COASTAL FLOODING...
Increasing southerly flow from Monday evening into Tuesday
could lead to water levels approaching minor flood stage,
especially at Annapolis.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
     ANZ533-534-537-543.

&&

$$

DISCUSSION...ADS
AVIATION...ADS
MARINE...ADS