Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

315
FXUS61 KLWX 111453
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1053 AM EDT Sat Jul 11 2026

.WHAT HAS CHANGED...
No major changes were made to the forecast this morning. We
continue to monitor the potential for thunderstorms this
afternoon and evening.

&&

.KEY MESSAGES...
- Heavy showers and strong thunderstorms, a few of which may
  produce damaging winds and flash flooding, are possible this
  afternoon and evening.

- Heat and humidity return for Wednesday through Saturday

&&

.DISCUSSION...
KEY MESSAGE 1...Heavy showers and strong thunderstorms, a few of
which may produce damaging winds and flash flooding, are possible
this afternoon and evening.

KEY MESSAGE 1 DESCRIPTION...

As of 10 AM, visible satellite imagery shows mostly sunny skies
in place across much of the area, with high clouds just starting
to stream in from the west. We remain in a warm and humid
airmass, with dewpoints holding in the upper 60s and lower 70s,
and air temperatures forecast to climb into the mid to upper
80s by later this afternoon. Moisture extends through the depth
of the column, with the 12z IAD sounding showing near
saturation nearly all the way up to the tropopause. The sounding
had a precipitable water value of of 1.84 inches, and that
value could increase slightly over the course of the day.

With no real capping evident on the 12z IAD sounding or forecast
soundings from various sources of model guidance, storms are
expected to form this afternoon in response to daytime heating.
At the moment, there aren`t any notable surface boundaries
present across the area to focus the development storms, but
there are a few areas that we`ll continue to monitor. The first
is in the vicinity of bay and river breezes during the early to
mid afternoon hours, which could serve as localized areas of
low-level convergence that may be able to initiate storms (as
suggested by models such as the HRRR). Overall coverage of
storms should remain low along the bay/river breezes.

The second area we continue to monitor is off to our west across
OH/WV, where a remnant MCV is sparking the development of
showers and storms. Model guidance shows additional development
of storms this afternoon to the west of the Blue Ridge as the
MCV spreads eastward. These storms will slowly drift toward the
south and east during the afternoon and early evening hours.

Finally, a third area we continue to monitor is up to our north
in PA. A cold front located across northern portions of the
state at the moment will continue to make southward progress
through the day as high pressure continues to build to our
north over the Great Lakes. Convergence along this boundary will
likely lead to additional areas of more focused thunderstorm
activity. These storms will drop southward into our forecast
area during the evening hours. With an unstable airmass in
place, these storms may persist well after dark from the DC
Metro southward to southern MD, until the front finally clears
the area later tonight.

Forecast soundings show an environment with saturated profiles
through the vertical, around 1000 J/kg of MLCAPE, 400-600 J/kg
of DCAPE, and around 20-30 knots of mid-level flow. While this
environment isn`t overly favorable for strong downbursts, an
instance or two of damaging winds can`t be completely ruled out.
SPC has much of the forecast area outlooked in a Marginal Risk
(level 1 of 5) for severe thunderstorms.

With the saturated profiles, deep warm cloud layers (around 14k
ft), and precipitable water values approaching 2 inches, storms
today should be very efficient heavy rainfall producers.
However, ample flow in the mid to upper levels should enable
storms to be somewhat progressive. The weak low-level jet and
lack of focused areas of stronger low-level convergence should
also limit backbuilding to a degree. However, it`s possible that
there could be an isolated instance or two of flash flooding if
localized storm mergers are able to prolong the period of
heavier rain. The best chance for this to occur may be later
this evening along the I-95 corridor, where flash flood guidance
is lower, and there could be some potential for storms moving
in from the west to collide with storms moving in from the
northeast. At this time, the threat for flooding appears to be
low (not rising to a threat level worthy of a Watch), but non-
zero. We`ll continue to monitor trends over the course of the
day. WPC currently has much of the area outlooked in a Marginal
Risk (level 1 of 4) for excessive rainfall.


KEY MESSAGE 2...Heat and humidity return for Wednesday through
Saturday.

KEY MESSAGE 2 DESCRIPTION...
Surface high pressure will bring dry conditions with lower humidity
for Monday and Tuesday. However, the subtropical ridge will build
over the central CONUS Tuesday and it will spread east toward the
Mid-Atlantic for Wednesday through Friday. The center of the ridge
will be off to the west, but there will be enough subsidence for a
return of hot conditions. Heat indices  around 100 degrees with
temperatures well into the 90s are most likely for the valleys and
urban areas. It may even turn out a bit hotter with respect to heat
indices depending on what dewpoints will mix down to around peak
heating each day. It does not appear that it will be as extreme as
it was earlier in the month, but still quite hot and humid for
Wednesday through the end of next week.

With the increased heat and humidity there may be some showers and
thunderstorms. A few of those storms can be strong, but confidence
is low at this time. Perhaps the best chance for storms will be
Friday where low-level moisture may be more prominent in response to
High pressure building over the Atlantic.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions expected at all terminals today. There is a risk
of strong to severe thunderstorms this afternoon and evening
that could reduce conditions to MVFR and IFR briefly.

Sub-VFR ceilings are possible tonight into Sunday morning in
northeast flow behind a cold front.

VFR conditions are most likely Sunday afternoon through
Wednesday.

&&

.MARINE...
Light flow below 10 kt is expected today, but t-storms this
afternoon and evening may pose a risk of strong winds and
frequent lightning. SMWs may be required this afternoon and
evening. Onshore flow may enhance Sunday into Sunday night
before turning southerly Monday.

A west to southwest flow is expected Tuesday and Wednesday. Winds
may gust around SCA criteria during this time since there will be a
gradient between high pressure to the south and west vs lower
pressure to the north and east.

&&

.TIDES/COASTAL FLOODING...
Elevated water levels will persist for the next couple of days
with minor coastal flooding becoming increasingly likely Monday
into Tuesday as southerly flow strengthens.

&&

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

&&

$$

DISCUSSION...KJP/BJL
AVIATION...BJL/LFR/KLW
MARINE...BJL/LFR/KLW