Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

738
FXUS61 KLWX 260740
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
340 AM EDT Wed Aug 26 2026

.WHAT HAS CHANGED...
Severe thunderstorm threat is increasing on Thursday, so spoke
to that a bit more in detail in Key Message 1.

&&

.KEY MESSAGES...
- 1) Increasing risk for severe thunderstorms amidst
  increasingly warm and humid conditions ahead of an approaching
  cold front.

- 2) Drier conditions heading into the weekend, with increasingly
  hot & humid conditions at the start of next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Increasing risk for severe thunderstorms amidst
increasingly warm and humid conditions ahead of an approaching
cold front.

Today marks a shift in the weather pattern from recent days as
high pressure pushes offshore. This will turn winds out of the
south, yielding a much more humid tropical air mass. The process
of moisture transfer will just be starting today, so dew points
only jump back into the mid 60s, but it will set the stage for
the pre-frontal environment on Thursday. Highs today reach the
mid to upper 80s for most, and the 70s in the higher elevations.
It looks like the atmosphere should remain capped most of the
day, although a pop up shower along the terrain could occur in
the afternoon.

Moisture return increases overnight along a northward-lifting
warm front, which could result in some scattered showers and
storms overnight into Thursday morning. How much activity occurs
overnight could have implications on the rest of the day, but
probabilities remain rather low overall. At any rate, there will
likely be some cloud cover at the very least. Whether or not
this clears out later in the morning will have large
implications on the overall severe threat.

More notable forcing arrives Thursday as an upper level trough
and surface cold front approach from the northwest. However,
these forcing features may be somewhat displaced from the local
area during peak diurnal heating. The front will lag to our
northwest, while the strongest forcing with the trough passes
to the north. A secondary shortwave may approach but not until
the evening. Thus there remains some uncertainty in the coverage
and timing of any showers and thunderstorms. There could even be
two rounds, dependent upon whether that morning cloud cover
clears out early enough. If everything does come together
though, moderate instability combined with deep-layer shear of
around 25-35 kt could result in some severe thunderstorms. Mid-
level lapse rate don`t look all that unimpressive, so in
addition to the primary damaging wind threat, large hail is also
going to be a possibility. Wouldn`t even be shocked to see a
supercell or two. Some of the more aggressive model guidance,
particularly the HRRR, does paint some rather impressive veering
low-level wind profiles over the region in forecast soundings.
If this scenario were to come to fruition, there would also be
a non-zero tornado threat. Not that this is the most likely
scenario, but worth mentioning at this point. It is also worth
noting that the Storm Prediction Center did drop the Slight Risk
area southward into our area, particularly along the MD/PA
border east of the Blue Ridge. This matches the thinking here in
an increased severe weather threat compared to our thinking the
past few days.

The cold front may bisect the area by Friday morning while the
mid/upper level trough axis remains to the west. Some showers
and thunderstorms will continue to be possible near and south of
the front, although the risk for strong thunderstorms is lower.


KEY MESSAGE 2...Drier conditions heading into the weekend, with
increasingly hot & humid conditions at the start of next week.

Upper-level zonal flow returns over the Mid-Atlantic by Saturday in
the wake of the cold front. A few diurnal showers & thunderstorms
remain possible throughout the early weekend, but overall conditions
become progressively drier as surface high pressure tracks across
the Blue Ridge. Temperatures remain seasonable during this period,
with daily highs ranging in the mid-to-upper 80s during the day.

Towards the start of next week, broad upper-level ridging starts to
build over the Southeast. Combined with relatively moist air aloft,
heat & humidity here will start to feel like peak summertime
conditions once again, with dewpoints ranging in the low-70s over
the metros and highs in the lower 90s by next Monday. 850 mb temp
anomalies show this pattern only continuing to build in the long-
term, which may lead to a warmer-than-average start to September
should this pattern persist. Thunderstorm chances could gradually
increase during this period as ridging transitions offshore.
Regardless, anticipate a return to summertime heat & humidity here
in the Mid-Atlantic should this upper-level setup persist.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
As high pressure pushes offshore today, southerly winds will
gust up to 15 to 20 knots. Some isolated to scattered showers
may impact the terminals by Wednesday evening/night.

A cold front will approach the region on Thursday. A few strong
to severe storms are possible that afternoon/evening, with
gusty winds being the primary threat. There are even some indications
that a couple of rounds of storms are possible, one in the
early afternoon and one later in the evening.

As the front stalls nearby Thursday night, some MVFR to IFR
ceilings or visibilities may develop. Showers and storms could
even linger into Friday, but unsure if this would impact any of
the terminals at this time, as the front should stall east of
I-95 and focus that threat east of most of the terminals. Can`t
completely rule out some restrictions though.

Prevailing VFR conditions are expected Saturday. Winds shift
out of the north to northeast on Saturday and are expected to
remain light.

&&

.MARINE...
Winds become southerly today as high pressure pushes offshore,
and will increase during the afternoon. The greatest
probability for 20 kt gusts will arrive this evening/tonight
due to channeling. An SCA has been issued for many locations
along the Chesapeake.

With the next cold front not arriving until late Thursday,
there are some hints of some 15 to 20 knot southerly gusts
continuing on Thursday. The front will also bring the risk of
strong, gusty thunderstorms, which would likely necessitate
SMWs. There are even some indications that a couple of rounds of
storms are possible, one in the early afternoon and one later in
the evening.

Sub-small craft advisory level winds are expected on Friday as a
cold front moves in from the north west. Special Marine Warning
could be possible as Friday`s thunderstorms move over the waters.
Sub-SCA level north to northeasterly winds are forecast for
Saturday.

&&

.TIDES/COASTAL FLOODING...
Increasing southerly flow develops through tonight, leading to
rising water levels. Most locations will only see action stages,
but Annapolis could approach minor flood stage early Thursday
morning.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 6 PM this evening to 6 AM EDT
     Thursday for ANZ531>534-537-539>541-543.

&&

$$

DISCUSSION...CJL/SRT
AVIATION...CJL/SRT
MARINE...CJL/SRT