Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

031
FXUS61 KLWX 070709
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
309 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 Friday into the
upcoming weekend. 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. A dry and muggy start
with some fog giving way to mostly sunny to partly cloudy skies in
the afternoon. The combination of the heat and humidity with boost
surface based CAPE values above 2000 j/kg+ with DCAPE values
remaining around or less than 1000 j/kg. 0-6 km shear values will
sit between 25-30 kts with mid level lapse rates between 6-7.5 C/km
which would allow for higher storm coverage and more progressive
movement from west to east across the region. Storms will initiate
in the lee of the Alleghenies around 18-20z/2-4pm before advancing
eastward toward the metros toward the late afternoon and evening
rush hours commute 21-00z/5-8pm as the impulse works through. Storms
could fire ahead of the shortwave via the bay/river breeze similar
to what we had on Thursday. With all that saId, SPC has upgraded the
areas near and along the I-95 (DC/NORTHERN VA burbs northeast
into central MD) into 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.

Similar conditions are expected Saturday as another potent shortwave
passes through. Instability will remain high as a result of the high
heat and humidity. Shear values will sit around 30 kts perhaps
increasing to 35 kts as the subtropical jet stream begins to
strengthen. This could yield a more organized severe weather threat
with aligns with current learning machine 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 Monday, 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 /07Z 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. For Friday, expected storms to fire
west of MRB between 17-19z/1-3pm before advancing eastward into
the corridor (IAD-BWI-DCA) between 20-01z/4-9pm. PROB30s will be
used to encompass this threat given the coverage being widely
scattered across the region. A similar set up is expected
Saturday afternoon and evening with less coverage Sunday.
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...
Small Craft Advisories may be needed for portions of the waters
through Saturday due to southerly channeling mainly in the afternoon
and evening. Most days will see marginal conditions just below the
threshold, especially over the open waters. Daily shower and
thunderstorm chances are expected each afternoon and evening through
early next week. The greatest coverage will be on Friday and
Saturday afternoon/evening. Special Marine Warnings may be needed to
encompass any any stronger thunderstorms that may form. Storms will
capable of producing frequent lightning and wind gusts over 35
knots.

&&

.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...None.

&&

$$

DISCUSSION...CJL/EST
AVIATION...CJL/EST
MARINE...CJL/EST
TIDES...LWX