Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

134
FXUS61 KLWX 100634
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
234 AM EDT Mon Aug 10 2026

.WHAT HAS CHANGED...
Monitoring a decaying MCS this morning over western PA and another
over the Ohio River Valley that brings the potential for severe
weather this afternoon and evening.

&&

.KEY MESSAGES...
- 1) An active start to the new workweek with multiple chances for
severe weather. Hot temperatures and high humidity continue.

- 2) Turning cooler toward the end of the week, although showers
  and thunderstorms remain possible at times.

&&

.DISCUSSION...
KEY MESSAGE 1... An active start to the new workweek with multiple
chances for severe weather. Hot temperatures and high humidity
continue.

Shaping up to be a fairly active weather pattern today through
Wednesday as multiple pieces of shortwave energy traverse the
region. This morning we continue to monitor a decaying MCS as it
moves across western PA, north-central WV, and toward far western MD
early this morning. Most of the guidance dissipates this activity as
it continues east with just a few residual showers and mid/high
level clouds along the Alleghenies and north of the PA/MD line.
Residual outflows from this system combined with an additional MCS
back across the central Ohio River Valley this morning and a lee
side trough will set the stage for thunderstorm development this
afternoon and evening. Depending on how this MCS maintains itself
across our forecast area today, or have its remnant outflow focus
the development of new convection tomorrow afternoon. If the MCS
were to totally fall apart before crossing the mountains, with no
remnant cold pool making it further east, the development of
thunderstorms across our area would be a bit more in question, given
only weak large scale forcing for ascent and questions about
where/if a lee trough would set up.

What we do know is that whatever occurs the ingredients will be
there for severe weather development. This is due largely in part to
strong daytime heating with highs in the upper 80s and mid 90s.
Dewpoints will remain in the upper 60s to mid 70s yielding heat
index values around 100 degrees east of the Blue Ridge. The heat
combined with a shortwave disturbance aloft should be the kicker for
at least a few severe thunderstorms to develop. Current CAM guidance
suggest a mash up between scattered clusters to a linear line of
storms peeling off the Alleghenies between 1-9pm. Storms will
initialize over the mountains between 2-4pm before advancing east
into the metros between 4-8pm. SPC has expanded the Slight Risk
(Level 2 out of 5) for locations along and north of I-66/US-50 with
a Marginal Risk (Level 1 out of 5) across the rest of the region
(outside of locations south of I-64). Damaging winds will be the
primary threat with storms along with isolated large hail and
isolated instances of flash flooding. Machine guidance continues to
advertise a high ceiling on the severe threat with WxNext2
probabilities of 45-70 percent and CSU probabilities of 15 to 30
percent across the area this afternoon and evening. Damaging winds
will be the primary threat with storms along with isolated large
hail and isolated instances of flash flooding.

Additional shortwave disturbances look to pass through Tuesday into
Wednesday. Mid-level flow will increase during this time along with
stronger height falls yielding more widespread convective chances.
With that said, uncertainty remains in regards to timing, coverage,
and location of the storms during the period. This is largely due in
part to the evolution of any MCSs ejecting out of the Ohio River
Valley/Great Lakes region along with the remnant outflows left
behind. Right now, Tuesday appears to be the day with the greatest
coverage of showers and thunderstorms along with an increased risk
for severe weather. SPC maintains a Slight Risk (Level 2 out of 5)
for eastern WV/far western MD and the Shenandoah Valley. A Marginal
Risk (Level 1 out 5) has been outlooked elsewhere across the region
for Tuesday into Tuesday night. Damaging winds will once again be
the main threat along with isolated large hail and isolated
instances of flash flooding.

Beyond Tuesday, timing, coverage, and locations of storms remains
uncertain despite strong mid level flow and increased height falls
across the region. Shortwave disturbances will continue to pulse
through although more cloud cover may be noted which could dampen
the threat. SPC continues to highlight Wednesday into Wednesday
night with 15 percent probs for severe weather. This aligns with
machine learning probabilities of 10-30 percent probs across the
area. These probabilities taper even more late week as the front
finally drops into the region. Once again damaging winds will be the
main threat with storms along with isolated instances of flash
flooding.


KEY MESSAGE 2...Turning cooler toward the end of the week, although
showers and thunderstorms remain possible at times.

Daily storm chances look to continue through at least Friday as a
frontal system tracks toward the region. Ahead of that front will be
several fast moving shortwave disturbances which will help aid in
shower and thunderstorm development during the diurnal periods.

Th southward progress of the cold front becomes more uncertain for
the end of the week, although it likely drifts south with time
(especially Friday into Saturday). Both physics-based and AI
guidance shows lower severe weather chances Thursday with declining
instability. Showers and thunderstorms could remain possible though
with the front nearby. For Friday and Saturday in particular, there
may be a better chance of drying out as high pressure builds to the
north. This will also bring a corresponding cool down in
temperatures (potentially a bit below normal) along with lower
humidity. The front won`t be too far to the south however, and will
likely attempt to lift north later this weekend or early next week
as a low pressure system moves into the Great Lakes. Thus, some low
end PoPs remain in the forecast each day through the end of the
forecast period.

Temperatures will cool from the upper 80s and low 90s Thursday into
the low to mid 80s Saturday. Overnight lows will fall back into the
low to mid 60s with 50s over the mountains.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR conditions look to prevail across the terminals through Friday
given subtropical high pressure offshore and the lack of any
significant front passing through. Brief periods of sub-VFR
restrictions are likely during the afternoon and evening hours due
to thunderstorms, especially today through Wednesday. Thunderstorm
coverage lowers Thursday and Friday as a front gradually sags
through the region.

Storm coverage increases this afternoon and evening and again
Tuesday as multiple shortwave disturbances pass through. The risk
for severe weather is also increasing during this time with a focus
during the peak heating period 18z-02z/2-9pm this afternoon and
evening. Storms should initialize west of MRB between 16-19z/12-3pm
before advancing into the corridor between 19-23z-3-7pm. Storm
coverage remains uncertain with gusty winds, frequent lightning, and
locally heavy rainfall as the primary concerns. Similar conditions
are expected Tuesday and Wednesday with restrictions possible in the
afternoon and evening due to thunderstorms.

Outside of the thunderstorms expect patchy fog between the terminals
each morning through Thursday. Winds will remain light out of the
west and southwest at less than 15 kts.

VFR conditions are expected this upcoming weekend with isolated
showers and thunderstorms returning Sunday into early next week as
the front tries to lift back into the region.

&&

.MARINE...
A brief period of southerly channeling may return to the middle and
open waters of the Chesapeake Bay this afternoon and evening with
sub-SCA level winds over most of the waters. Overall sub-SCA level
winds are expected through Wednesday. Wind speed and direction are a
bit uncertain Thursday and Friday as a cold front gradually pushes
through the area. While winds appear to be mostly sub-SCA at this
time, there could be an enhanced northwesterly surge once the front
does push through.

Outside of the background winds, expect daily shower and
thunderstorm chances are each afternoon and evening through upcoming
workweek. Special Marine Warnings may be needed to encompass any
stronger thunderstorms that may form especially today through
Thursday. Damaging wind gusts and frequent cloud-to-ground lightning
will be the main threats between 18z-01z/ 2-9pm.

&&

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

&&

$$

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