Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

907
FXUS61 KLWX 071434
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1034 AM EDT Fri Aug 7 2026

.WHAT HAS CHANGED...
Rinse and repeat..Daily thunderstorm chances continue along with hot
and humid conditions through the upcoming weekend ahead.

&&

.KEY MESSAGES...
- 1) Patchy morning fog, high humidity, hot temperatures, and daily
thunderstorm chances continue through early next week.

- 2) A cold front could arrive late next week and into the weekend
bringing relief from the heat and humidity.

&&

.DISCUSSION...
KEY MESSAGE 1... Patchy morning fog, high humidity, hot
temperatures, and daily thunderstorm chances continue through early
next week.

More of the same when it comes to the forecast today and
Saturday. Patchy morning fog gives way to high humidity, hot
temperatures, and late day thunderstorm chances. This is largely
due in part to blocking high pressure offshore and continued
waves of upper level energy pivoting through. The nearest front
is back toward Chicago with little movement eastward in the
coming days due blocking high pressure offshore.

For today, expect similar conditions to what we saw Thursday
although the severe threat will be higher. Mostly sunny to
partly cloudy skies continue through the afternoon, with
building heat and humidity. High temperatures are expected to
rise well into the 80s and low 90s, with dew points in the 70s
yet again. Yesterday this yielded around 2000-3000 J/kg of
MLCAPE, so would expect similar values today, perhaps even a
touch higher owing to steeper mid-level lapse rates. DCAPE
values are expected to remain around 500-700 J/kg again today,
which is just enough to bring down 60+ mph downdrafts. With wind
shear slightly higher today (around 25-30 knots) and the
aforementioned higher mid-level lapse rates (around 6-7.5 C/km),
there will be an increased risk for severe storms today
compared to yesterday.

Storms will initiate in the lee of the Alleghenies around
17-19z/1-3pm before advancing eastward toward the metros toward
the late afternoon and evening rush hours commute 20-00z/4-8pm
as the impulse works through. As storms move east, would expect
them to grow upscale somewhat, potentially getting semi-
organized into a few bowing clusters. This would be the best
shot of damaging winds. With shear only around 25-30 knots at
best though, these may be short-lived, then perhaps redevelop
on existing outflows. Storms could also develop well ahead of
the shortwave via the bay/river breeze similar to what we had on
yesterday as well.

All of this being said, SPC has areas near and along the I-95
(DC/NORTHERN VA suburbs northeast into central MD) in a Slight
Risk (Level 2 out of 5) for severe weather this afternoon and
evening. The main threats with storms look to be damaging winds
(15% probabilities) and heavy rainfall although isolated large
hail cannot be ruled out due to the higher mid-level lapse
rates. Additionally, torrential rainfall could result in
isolated instances of flash flooding in areas that are more
susceptible to flooding. Lastly, frequent cloud-to-ground
lightning can be expected with storms today, likely well ahead
of and behind storms. Use extreme caution if outdoors later this
afternoon and remember that when thunder roars to head indoors!

Somewhat similar conditions are expected Saturday as another
potent shortwave passes through. The main difference is that
mid-level flow turns a bit more W to WSW versus the SW`ly flow
we have had in recent days. As a result, coverage of storms is
likely to be less than what we see today. However, shear values
increase a bit, reaching 30 to 35 kts as the subtropical jet
stream begins to strengthen. Mid-level lapse rates are also
impressive, similar to today`s event. Instability will be a bit
less tomorrow, owing to the westerly mid-level flow.
Thermodynamic profiles depict skinnier CAPE profiles, but
inverted-V signatures towards the surface. All of this to say,
while our area is not currently highlighted in a severe weather
risk area from SPC, it bears watching. Our thoughts are that the
coverage should be less tomorrow, but the ceiling could be
higher in terms of damaging wind potential, should storms be
able to develop and get organized. Current machine learning
guidance which suggest 15-30 percent probabilities for damaging
wind gusts Saturday afternoon and evening. With that said,
guidance continues to focus on areas along and north of
I-66/US-50 for both Friday and Saturday.

Convection begins to wane a bit Sunday into Monday given quasi-zonal
flow aloft. It will be short-lived with storm chances increasing
once again Tuesday, and Wednesday as a series of shortwave
disturbances passing through. By Wednesday and Thursday, a front
tries to drop into the region potentially bringing a change to
the current pattern.

Outside of the storm chances expect highs in the upper 80s and low
90s with heat indices east of the BLue Ridge up around 100 degrees.
The hottest days look to be Sunday through Tuesday given the
strengthened subtropical ridge over the region.


KEY MESSAGE 2...A cold front could arrive late next week and into
the weekend bringing relief from the heat and humidity.

While this is very far out in the forecast period, there is some
signal that a more potent frontal system could push through the
region late in the week. The details are murky at this stage of the
forecast, with timing very uncertain, as well as potential impacts.
Deterministic and ensemble guidance is generally between
Thursday/Friday right now, with improvement in the weather pattern
possible into the upcoming weekend. Any decent frontal passage in
the summertime should be watched closely for potential severe
weather, so we will keep monitoring this in the coming days to see
if that potential is there, and try to narrow down the timeframe a
bit more.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
Prevailing VFR conditions are expected across the terminals
through the middle of next week given subtropical high pressure
offshore and the lack of any real front passing through. Brief
periods of sub-VFR are likely during the afternoon and evening
hours due to thunderstorms, though Sunday and Monday look to
remain dry for most areas. Monday could see an isolated storm,
but looking less likely.

For today, expect storms to fire west of MRB between 17-19z/1-3pm
before advancing eastward into the corridor (IAD- BWI-DCA)
between 19-01z/4-9pm. TEMPOs were added with the last AMDs, as
confidence has increased that storms will move through in this
timeframe, just a matter of exactly when. Not expecting more
than 1-1.5 hrs of significant restrictions for most sites
within the 3-4 hour time window given. However, uncertainty
remains with exact start time at this point. Will try to refine
timing as storms develop later today.

A similar set up is expected Saturday afternoon and evening, but
with less coverage. Will look into this for the 18z updates, but
initial thoughts are going to be for PROB30s for now, as the
likelihood of storms tomorrow is less than today, and there is a
lot more uncertainty with convective initiation than we have
today.

Outside of the thunderstorms expect patchy fog between the
terminals each morning through early next week. Winds will
remain light out of the south and southeast at less than 15 kts.

&&

.MARINE...
SCA is in effect for portions of the Chesapeake Bay today due to
southerly channeling. However the bigger threat will be with
storms this afternoon/evening, which will likely necessitate
some SMWs. Damaging wind gusts and frequent cloud-to-ground
lightning will be the main threats.


Small Craft Advisories may be needed again on Saturday due to
southerly channeling mainly in the afternoon and evening.
Another chance for storms Saturday afternoon, which could again
bring damaging winds and frequent lightning. However, a bit more
uncertainty with tomorrow`s event in terms of coverage.

A break from showers and storms is expected on Sunday and Monday
with winds generally gusting 10-15 knots at most during the
afternoon/evening hours.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies climb through the weekend in response to return
southerly flow. Periods of coastal flooding are possible at times of
high tide at sensitive locations.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 11 PM EDT
     this evening for ANZ534-537-543.

&&

$$

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