Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

499
FXUS61 KLWX 311843
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
243 PM EDT Fri Jul 31 2026

.WHAT HAS CHANGED...
Small Craft Advisories were issued across the tidal Potomac as
well as the Chesapeake Bay (including adjoining tributaries) on
Saturday into Saturday night. Otherwise, the signal of active
weather persists on Sunday into next week as a slow moving
closed low approaches from the west.

&&

.KEY MESSAGES...
- 1) Increasing shower and thunderstorm chances along with high
  humidity Sunday into much of next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Increasing shower and thunderstorm chances along
with high humidity Sunday into much of next week.

The current frontal analysis places a stalled boundary near
Savannah, Georgia while stretching back into the Ozarks. At the
same time, an occluded frontal system continues to spin off the
coast of Nova Scotia. In between, the Mid-Atlantic region up
into New England remains under the influence of surface high
pressure. This is providing continued tranquil weather
underneath a mixture of sunshine and shallow fair weather
cumulus. Plenty of daytime solar insolation has helped push
early afternoon temperatures into the low/mid 80s, accompanied
by dew points mainly in the upper 50s to mid 60s. Winds remain
light and somewhat variable owing to the anticyclone over the
region. Expect minimal change through the remainder of the
afternoon and evening. Heading into the overnight hours, low
temperatures will fall into the 60s to low 70s, with upper 50s
along the Allegheny Front. Clouds begin to increase late in the
night, but conditions are to remain dry.

The primary feature of interest for the weekend into early next
week is a slow moving upper low currently spinning near southern
Minnesota into Iowa. Aside from a few isolated showers across
higher elevations of the Potomac Highlands, Saturday will be
another dry day for the Mid-Atlantic region. The most notable
change will be the shift to southerly flow which slowly
increases humidity levels. This becomes even more noticeable by
Sunday into the first full week of August. Additionally, expect
another uptick in temperatures with highs reaching the upper 80s
to low 90s. Afternoon wind gusts push into the 20 to 25 mph
range depending on how mixed the boundary layer becomes. A
milder night lies ahead given mostly cloudy skies and warm
advection flow. Many spots should see lows in the upper 60s to
low 70s, with spotty mid 70s across the urban hubs.

Sunday and Monday present a more active pattern as the upstream
closed low slowly moves across the Ohio Valley. There is some
potential for severe thunderstorms across areas west of I-95.
Areas to the east largely stay under residual ridging aloft
which should limit the convective potential. The Storm
Prediction Center currently places the former region in a
Marginal Risk (Level 1 of 5). Precipitable water values rise
into the 2 to 2.25 inch range which will enhance the potential
for heavy rainfall in any thunderstorm cores. The overall setup
changes little into Monday, albeit with the upper low in closer
proximity to the Appalachians. A modified tropical air mass
remains in place which comes with a weakly defined west-east
oriented frontal zone. Current limitations from a discernible
flood risk would include (1) Weak low-level convergence, (2)
Limited instability, and (3) Ongoing drought conditions. Will
continue to monitor as additional model guidance arrives.
Overall temperatures remain near to slightly below average owing
to showers and cloud cover.

Shower and thunderstorm chances continue each afternoon and evening
beyond Monday as we enter more of a typical Summertime pattern. The
mean upper level trough and cutoff low will shift north and east
with a residual boundary leftover near the coast Tuesday into
Wednesday. As the low pulls further away several weak pieces of
shortwave energy will pivot around it adding extra lift for
dally shower and thunderstorm development. The greatest
concentration of storms will likely be over the terrain and
in/around where the bay/river breeze sets up. Overall coverage will
remain scattered, but likely amplified during the peak heating
period given the high PWATS (1.5-2"+) sitting over the region. With
that said, any flood threat would remain relegated to poor drainage
areas pending repetitive rounds of storms or if storm track/sit over
an urban location. Highs get back close to 90 Tuesday through Friday
next week. Overnight lows will fall back into the mid to upper
60s.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions should continue through Saturday given the
influence of high pressure over the area. Initial light winds
will give way to increasing southerly flow on Saturday.
Afternoon gusts up to 20 knots are expected, possibly a bit
higher if the boundary layer is sufficiently mixed. Any possible
restrictions should hold off until Sunday, particularly for the
western TAF sites where a threat for isolated thunderstorms
exists. Shower chances increase into Sunday night which will
likely yield sub-VFR conditions as ceilings lower.

Expect sub-VFR conditions to continue at times Monday as the front
and cutoff low pressure system slowly exits the region. The front
will stall nearby or just to the south of the region Tuesday and
Wednesday keeping brief MVFR to IFR conditions, especially near
KCHO. South to southwest winds are expected at 5 to 10 kts before
becoming northeast Tuesday and southeast Tuesday night into
Wednesday.

&&

.MARINE...
Tranquil conditions are expected across the waterways through
Saturday morning. Southerly winds increase for the second half
of Saturday into Sunday morning. Small Craft Advisories have
been issued with this uptick in wind gusts which push into the
20 to 25 knot range. With advisory caliber winds expected again
on Sunday into Monday, Small Craft Advisories will likely need
to be extended during this period. Convective chances increase
on Sunday and Monday, particularly during the afternoon/evening
hours. Special Marine Warnings may be required for any stronger
convection.

Overall no marine hazards are expected Monday night through
Wednesday morning. Southerly channeling is possible over portions of
the waters Wednesday and Thursday.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies are forecast to slowly rise this weekend as
southerly flow returns. Sensitive tidal locations will reach Action
Stage during high tide cycles, with Annapolis forecast to reach
Minor Flood Stage during the Saturday morning high tide cycle.
Other locations could also approach Minor Flood Stage this
weekend.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 5 PM Saturday to 4 AM EDT Sunday for
     MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 5 PM Saturday to 4 AM EDT Sunday for
     ANZ530-531-538-539.
     Small Craft Advisory from 2 PM Saturday to 4 AM EDT Sunday for
     ANZ532>534-537-540>543.
     Small Craft Advisory from 2 PM to 11 PM EDT Saturday for
     ANZ535-536.

&&

$$

DISCUSSION...BRO/EST
AVIATION...BRO/EST
MARINE...BRO/EST
TIDES/COASTAL FLOODING...LWX