Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

215
FXUS61 KLWX 250049 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
849 PM EDT Mon Aug 24 2026

.WHAT HAS CHANGED...

Some showers developed over southern MD along a secondary front,
but are on their way out. Additional showers are possible across
the southernmost tip of St. Mary`s County and the adjacent
waters, but should exit our forecast by area by 03Z. Otherwise,
no changes.

&&

.KEY MESSAGES...
- 1) High pressure will support tranquil weather through
  Tuesday.

- 2) Turning more warm and humid through Thursday, with
  increasing thunderstorm chances, before high pressure returns
  for the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...High pressure will support tranquil weather
through Tuesday.

A vertically stacked area of low pressure remains centered over
southwestern Quebec. This ties to a occluded frontal system
which extends along the New England coast into the eastern
Carolinas. While characterized by 500-mb height departures on
the order of 2 to 2.5 standard deviations below climatology, any
direct impacts remain off to the north.

Given dew points are in the 50s to low 60s, this dry air mass
will support a decent cooling trend into the evening and
overnight period. Winds remain light overnight as an anticyclone
approaches from the Ohio Valley. Coupled with mainly clear
skies, ample radiational cooling effects are likely which will
favor 50s to low 60s.

The dome of high pressure remains in charge on Tuesday while the
earlier front stays along the southeastern U.S. coast. This does
come with an uptick in temperatures as the upper low lifts
poleward which yields a height/thickness rise. Northwesterly
gradients persist which helps maintain the lower humidity air
mass. High temperatures on Tuesday are expected to top out in
the low/mid 80s (upper 60s to 70s in the mountains). Tuesday
night`s lows will rise a bit given some added cloud cover.


KEY MESSAGE 2...Turning more warm and humid through Thursday,
with increasing thunderstorm chances, before high pressure
returns for the weekend.

The early week surface anticyclone begins to depart off the
Atlantic coast by Wednesday. Clockwise flow around this exiting
high pressure will usher in a southerly wind through the day.
Some afternoon gusts up to 20 mph are possible depending on the
degree of vertical mixing. High temperatures begin to approach
the 90 degree mark, which comes with a gradual uptick in dew
points/humidity levels. This is accompanied by the expected
increase in overnight warmth.

An upper trough currently crossing southern Saskatchewan is
likely to impact the local weather by Wednesday and Thursday.
While much of Wednesday should be dry, some weak/modest
perturbations in the flow ahead of the trough could bring some
late day showers. However, the more notable forcing from this
trough does not arrive until Thursday. A mixture of
thermodynamic ingredients are in place for this event, but it is
difficult to say if these will align or not. While instability
levels increase with the uptick in low-level moisture, vertical
shear generally averages around 20 to 25 knots. Some isolated
severe thunderstorms are possible, but the overall setup lends
itself to a number of question marks. However, Thursday does
look like a typical late August day with a front encroaching on
the region. This would be characterized by numerous showers and
some thunderstorms, many of which will bring heavy downpours and
frequent lightning. Any thunderstorm threat may linger into the
night with the cold front being a late arriver.

Heading into Friday and the weekend, an upper-level trough
begins to move directly over our forecast area. With highs
remaining in the mid 70s to 80s, warm and humid conditions
return to our region. This airmass brings with it chances for
showers and thunderstorms Friday afternoon and evening.

On Saturday and Sunday, the upper air wave pattern flattens into
zonal flow. Depending on whether this synoptic pattern holds,
Saturday and Sunday could see a few diurnally driven showers
and thunderstorms.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected to prevail through at least Tuesday,
if not longer. This is in response to an approaching area of
high pressure which settles over the region by Tuesday. Winds
will be somewhat variable in direction at times given this ridge
of high pressure. As this system pushes offshore, southerly
winds return for Wednesday with afternoon gusts up to 15 to 20
knots. Some showers may impact the terminals by Wednesday
evening/night, a few of which may warrant some restrictions.
With a cold front impacting the area on Thursday, sub-VFR
conditions are expected. A few strong to severe thunderstorms
are possible that afternoon/evening. Restrictions could linger
into Thursday night with the cold front moving through
overnight.

Depending on the frontal timing, showers may linger into Friday
which would favor a few additional restrictions. High pressure
moves in for the weekend which should yield more favorable
flying conditions.

&&

.MARINE...
Winds will be somewhat variable through this evening before
turning more northerly tonight as the dome of high pressure
pushes in from the west. Northerly channeling effects could
bring a few 18 knot gusts to wider portions of the Chesapeake
Bay tonight. Wind gusts drop off through Wednesday morning
before another ramp up ensues for the second half of Wednesday.
Southerly channeling effects will likely warrant Small Craft
Advisories across portions of the waters through Wednesday
night. With the cold front not arriving until late Thursday,
there are some hints of some 15 to 20 knot southerly gusts on
Thursday. This also comes with the risk of stronger convection,
many capable of needing Special Marine Warnings.

Scattered showers & thunderstorms Friday could also create
locally gusty winds over the waters, perhaps necessitating a few
SMWs.

&&

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

&&

$$

DISCUSSION...LFR/BRO/KVH
AVIATION...LFR/BRO/KVH
MARINE...LFR/BRO/KVH