Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

418
FXUS61 KLWX 032336
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
736 PM EDT Mon Aug 3 2026

.WHAT HAS CHANGED...
Risk of showers and thunderstorms is pushing south. Small Craft
Advisory issued for late tonight/Tuesday morning.

&&

.KEY MESSAGES...
- 1) A relative break in rain chances is expected through
  Tuesday.

- 2) Increased shower and thunderstorm chances Thursday into
  early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...A relative break in rain chances is expected
through Tuesday.

The cold front can be analyzed from roughly the upper eastern
shore to central Shenandoah Valley at 7PM, with upper 50s/lower
60s dew points in its wake. Showers and thunderstorms are now
relegated to far southern Maryland and central Virginia. While
this remaining activity should push south over the next few
hours, some CAMs continue to show a few showers popping up until
the front pushes farther south. In the near term, that is being
aided slightly by upslope winds along the Blue Ridge in central
Virginia.

For areas to the north of the convection, skies have cleared out
rather quickly. A few local exceptions are noted as anvil cirrus
continue to lift northeastward to near the metro areas. This
drying effect is evident on the multi-channel water vapor
imagery as the mean longwave trough axis passes through. While
the stronger forcing is displaced well to the north into upstate
New York and southern Quebec, enough height falls cross the
local area to push this front through. By late this evening, the
cold front is expected to span southeastern Virginia back
across interior North Carolina. The post-frontal air mass will
remain dry, although some clouds may remain across the southern
half of the area.

After spending much of the day in the low/mid 80s, expect
temperatures and dew points to fall into tonight. With high
pressure building in from the upper Ohio Valley, forecast lows
are to fall into the upper 50s to 60s. For the Alleghenies, some
locations could even push into the mid 50s. The Shenandoah
Valley westward may see some patchy fog for locations that fully
decouple overnight under clear skies and light winds.

During subsequent days through mid-week, expect more tranquil
weather to arrive on Tuesday. High pressure remains in charge as
the stalled front sticks closer to the Virginia Tidewater
region. Clouds increase from the south as moisture overruns the
frontal system to the south. Despite the clouds, forecast highs
push back into the 80s, but with lower humidity levels.
Seasonable conditions persist into Tuesday night while a few
showers approach from central Virginia and the Northern Neck of
Virginia.

Wednesday yields the next shot for showers and thunderstorms. At
the synoptic level, a cut-off low over the southeastern U.S.
weakens/shears while subtropical ridging retrogrades toward the
Atlantic coast. As this occurs, mid-level winds begin to
increase along the western flank of the offshore anticyclone. A
series of perturbations in the flow will lift across the area at
the same time the surface front returns to the I-95 corridor.
Precipitable water values shift back to over 2 inches which will
not only increase humidity levels, but also bring heavy rainfall
back to the forecast. A Marginal Risk for excessive rainfall
exists on Wednesday as this pattern shift unfolds. Highs remain
in the 80s with afternoon heat indices into the mid 90s.


KEY MESSAGE 2: Increased shower and thunderstorm chances
Thursday into early next week.

Synoptically, we are still monitoring the progression of an upper
level low pressure system over the Ohio River Valley/central
Appalachians. This system will be slow to push eastward heading into
the weekend and early next week. At the surface, is a
stalled/washed out boundary that will act as a catalyst for several
pieces of shortwave energy to move along yielding increased chances
for showers and thunderstorms during the afternoon and evening
periods each day.

Additional showers and thunderstorms are likely Thursday through
Sunday given the boundary washing out over the area. The warm/moist
airmass combined with the washed out boundary and ripples of
shortwave energy will aid in scattered to numerous diurnal
thunderstorm development. Severe weather could be a concern each
day, but overall confidence remains uncertain due to abundant cloud
cover and no real forcing mechanisms. Expect much of the convection
to be driven by terrain circulations or bay/river breeze
interactions. Current machine learning probabilities remain between
15-30 percent Thursday through Monday with 30-45 percent
probabilities east of the Blue Ridge Friday. Friday may be the day
where we have a more pronounced severe threat due to a lee side
trough combined with 30-40kt mid level flow driving convection
eastward. Locally damaging wind gusts will be the primary threat
with storms along with isolated instances of flash flooding.

Expect PWATS to remain between the 75th-90th percentile right on
through early next week. This is due to the lack of any real airmass
changing cold front holding off until the (beyond Tuesday) middle or
end of next week per latest long range guidance. As a result expect
increased humidity and above average temperatures across the region.
Highs will range from the mid to upper 80s and low 90s each
afternoon with heat indices up around 100 degrees east of the Blue
Ridge and over the I-95 metros late week. Once again it won`t be
raining all the time with plenty of dry time in between. Plan for
seasonable summer temperatures and oppressive humidity through the
extended period.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A few showers remain near CHO, but these should dissipate by mid
to late evening and will likely remain confined closer to the
spine of the Blue Ridge. Otherwise, VFR conditions should
prevail for all sites through Tuesday as the cold front sags
off toward the south. Multiple wind shifts will occur during
this time as initial post-frontal northwesterlies turn more
northeast to easterly in time. A shift to southerlies is
expected by Wednesday as the system returns northward as a warm
front. This brings shower and thunderstorm chances which carries
the potential for a few restrictions.

Expect periods of sub-VFR conditions to continue at times Thursday
through the upcoming weekend given increased chances for showers and
thunderstorms. The greatest coverage storms will be during the
afternoon and evening hours each day. Winds switch back to the south
and southwest Wednesday through the remainder of the workweek.
Speeds generally less than 15 kts.

&&

.MARINE...
A cold front will continue to push south across the waters
through this evening, shifting winds to the northwest. A few
thunderstorms remain possible across southern Maryland through
mid or late evening, but the risk for strong storms is
decreasing. After midnight, a surge of northeasterly winds will
spread across the area. Given the warm water temperatures, these
winds should easily mix down on the wider waters along the bay,
so a Small Craft Advisory has been issued from late tonight into
Tuesday morning. Winds will turn easterly then southeasterly
later Tuesday.

Wind speeds do not really pick up again until Wednesday as
southerly flow returns. Channeling effects across the wider
waters of the Chesapeake Bay could again reach 15 knots or so.
Convective chances return with the warm front which could yield
frequent lightning strikes and gusty marine winds.

SCA level southerly channeling is expected Thursday afternoon
through Saturday for portions of the waters. A few showers &
thunderstorms are possible over the waters during this period due to
a stalled front nearby. SMWs may be needed to encompass this threat
during the afternoon and evening hours.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will drop through Tuesday due to a wind shift
behind a cold front. Additional coastal flooding is possible at
times of high tide as sensitive locations as a result.
Anomalies climb again mid to late week in response to return
southerly flow.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from midnight tonight to 8 AM EDT Tuesday
     for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from midnight tonight to 8 AM EDT Tuesday
     for ANZ530>533-540-541.
     Small Craft Advisory from 3 AM to 11 AM EDT Tuesday for ANZ534-
     537-543.

&&

$$

DISCUSSION...ADS/BRO/EST
AVIATION...ADS/BRO/EST
MARINE...ADS/BRO/EST