Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

286
FXUS61 KLWX 120737
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
337 AM EDT Wed Aug 12 2026

.WHAT HAS CHANGED...
Mostly dry conditions Wednesday with increasing storm chances
Thursday and Friday as a cold front slides through. Quiet weather
conditions Saturday with more thunderstorms Sunday into early next
week.


&&

.KEY MESSAGES...
- 1) Shower and thunderstorm chances decrease today before
returning Thursday and Friday as a cold front crosses.

- 2) Dry conditions Saturday, with chances for showers and
  thunderstorms Sunday and Monday.

&&

.DISCUSSION...
KEY MESSAGE 1...Shower and thunderstorm chances decrease today
before increasing Thursday and Friday as a cold front crosses.

Looking at a lull in the thunderstorm activity today with subsidence
left behind the caravan of MCSs that traversed the region over the
last 24 to 48 hours. Overall flow remains out of the west and
northwest which is allowing slightly drier and much more stable air
to advect into the region. After a few light showers (mainly
Baltimore/east) and little patchy fog this morning, expect a spotty
shower or thunderstorm this afternoon, mainly as a result of terrain
circulations or the bay/river breeze. Skies will trend partly cloudy
to mostly sunny with abundant high cloud cover and even a little
wildfire smoke from fires burning over the Pacific Northwest/Canada.
The suspended smoke and high clouds will help limit destabilization
this afternoon with a focus, mainly south and west of our region.

The quiet weather doesn`t last too long as we monitor two shortwaves
set to track across the region. The first shortwave looks to cross
later this evening into Thursday morning (9pm-2am) with another
along the actual cold front Friday. Both of these disturbances will
allow for an uptick of shower and thunderstorm chances across the
region. Timing and coverage remain a bit uncertain yielding some
questions in regards to the overall severe threat. Instability and
shear do look to increase a bit with MLCAPE values around 1000-1500
j/kg and shear values up to 36 kts tonight into Friday. Machine
learning/AI guidance remains mixed on severe probabilities generally
ranging between 5-20 percent with a focus across southwestern
portions of the forecast area. If severe weather were to occur,
damaging winds and isolated instances of flash flooding would be the
primary concerns.

Outside of thunderstorms, look for seasonable temperatures and
increased humidity, especially Thursday and Friday ahead of the
frontal boundary. Highs will range from the mid 80s to low 90s (70s
mountains) with overnight lows in the mid 60s and low 70s (upper 50s
and low 60s mountains).


KEY MESSAGE 2... Dry conditions Saturday, with chances for showers
and thunderstorms Sunday and Monday.

High pressure will build to our north on Saturday. Northerly winds
will usher cooler and drier air into the area, with dewpoints
dropping into the 50s and lower 60s, and temperatures only making it
into the upper 70s to mid 80s. Conditions will remain dry beneath
mostly sunny skies.

High pressure will progress offshore on Sunday as low pressure and
an associated shortwave track through the Great Lakes. Winds will
turn out of the south in response, drawing deeper moisture back
north into the forecast area. Depending on the track of that system
and how much moisture return occurs ahead of it, showers and
thunderstorms may be possible for portions of the forecast area on
Sunday afternoon and evening. Additional showers and thunderstorms
may be possible again on Monday, before drier air works back into
the area on Tuesday.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will continue to prevail through Friday despite
temporary restrictions each morning due to patchy fog and each
afternoon due to thunderstorms.

Overall looking at dry/VFR conditions Wednesday given added
subsidence over the region. Winds will remain light out of the
west/northwest at less than 15kts. Shower chances may return tonight
as a wave of low pressure ripples through. Did add PROB30s in
at the corridor terminals between 03-08z/11pm-4am. Confidence
remains low for the timing of the showers/thunderstorms and
coverage with the bulk of guidance hinting at activity being
isolated to widely scattered.

Showers and thunderstorm chances increase again Thursday and Friday
pending the position of a cold front and the timing of any
additional disturbances. Outside of the thunderstorms expect patchy
fog between the terminals each morning. Winds will remain light
(outside of any thunderstorm outflows) between northwest and south
west.

Prevailing VFR conditions are forecast for both Saturday and Sunday.
Winds will be light out of the north to northeast on Saturday,
before turning out of the south on Sunday. An afternoon shower or
thunderstorm could be possible on Sunday, potentially leading to
brief restrictions at the terminals.


&&

.MARINE...
Sub-SCA level winds are expected today with an isolated shower or t-
storm over the waters. Overall no marine hazards today with the risk
of Special Marine Warnings Thursday and Friday afternoon as storm
chances increase ahead of a crossing cold frontal boundary.

Sub-SCA level north to northeasterly winds are expected on Saturday.
Winds will shift to out of the south on Sunday, with low-end SCA
level gusts possible during the afternoon and evening within
southerly channeling.


&&

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

&&

$$

DISCUSSION...KJP/EST
AVIATION...KJP/EST
MARINE...KJP/EST