Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

040
FXUS61 KLWX 041428
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1028 AM EDT Tue Aug 4 2026

.WHAT HAS CHANGED...
No significant changes were made to the forecast, but will
continue to monitor the threat of heavy rainfall for tonight as
12Z models come in this morning.

&&

.KEY MESSAGES...
- 1) Monitoring potential for localized urban flooding tonight
  as a warm front lifts north.

- 2) Daily shower and thunderstorm chances Wednesday through
 early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Monitoring potential for localized urban flooding
tonight as a warm front lifts north.

A stalled frontal boundary is currently located over the
Virginia Tidewater region while extending back into central
North Carolina. Any associated shower activity remains well
south of the local area this morning. However, clouds do
continue to lift up from southern Virginia, with further
expansion of cloud cover expected through the day. Looking at
dry conditions for most of the area today as the boundary
remains nearly stationary through the remainder of the morning.
However, the boundary is going to start lifting north as a warm
front this afternoon, then make steadier progress through the
area tonight. Showers and some thunderstorms push into parts of
Central Virginia this afternoon.

A cutoff mid-level low over the Deep South today retrogrades north
this evening, and that is what will push the warm front into our
area. As the front presses north, expect additional slow moving
shower and thunderstorms to develop across central VA, then up
toward the Washington DC and Baltimore Metro areas overnight
tonight into Wednesday morning.

There is a concerning signal in some of the high res guidance
that indicate potential for flash flooding in the metro areas
tonight. Convection appears to be enhanced from the development
of a broad wave of surface low pressure, or an MCV that develops
in the aftermath of diurnal convection. Either way, any slow
moving shower or thunderstorm tonight is going to be cable of
producing heavy rainfall in a short period of time. Tropical
moisture returns as PWATs surge to over 2" once again. This
likely yields high rain rates of 1-3" per hour in the heaviest
showers/thunderstorms. A Flood Watch may be needed for parts of
the area, but confidence is too low at this time. Will need to
carefully analyze the 12Z and later guidance to determine if the
threat for urban flash flooding is there tonight.

KEY MESSAGE 2...Daily shower and thunderstorm chances Wednesday
through early next week.

Ongoing showers and thunderstorms continue into Wednesday morning as
the warm front remains somewhere north of I-66. The cut-off low over
the southeastern U.S. weakens/shears while subtropical ridging
retrogrades toward the Atlantic coast. Increasing warmth and
humidity around the west side of the subtropical Atlantic ridge,
coupled with weak disturbances aloft will lead to afternoon and
evening showers and thunderstorms each day Thursday into early next
week. Mid-level flow appears strongest Thursday through the weekend.
Given the degree of instability with temps in the 90s and 70s
dewpoints, there could be a risk for severe thunderstorms each day.
Locally heavy rainfall is going to be possible each day, as well.
Increasing warmth and humidity yield heat indices around 100
Thursday through Sunday.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected through this evening for most of the
area. A stalled boundary south of the area is going to lift north as
warm front this afternoon into tomorrow. Sub-VFR conditions quickly
arrive at CHO early this evening, then at IAD/DCA late this evening,
and BWI/MTN/MRB late tonight. A period of moderate to heavy showers,
and possibly some thunderstorms, is likely to move across the area
tonight. IFR CIGs are becoming increasingly likely, with reductions
in visibility from heavy rainfall possible.

Sub-VFR conditions persist into Wednesday, though there is likely to
be a return to VFR conditions during the afternoon. Beyond that,
expect an active weather pattern through the weekend with daily
chances for showers and thunderstorms.

&&

.MARINE...
A stalled boundary south of the waters will lift north as a warm
front tonight. Southerly channeling is expected to develop at times
Wednesday through Friday, with Small Craft Advisories likely needed
for most of the waters. Additionally, daily chances for showers and
thunderstorms return to the forecast Wednesday through the weekend.
Any thunderstorm will be capable of producing wind gusts over 35
knots, in addition to lightning strikes.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies continue to decrease today as north winds continue.
Southerly winds will return tonight behind a warm front that lifts
north through the area. Anomalies climb again mid to late week in
response to return southerly flow. Additional 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...Small Craft Advisory until 11 AM EDT this morning for ANZ534-
     537-543.

&&

$$

DISCUSSION...LFR/BRO/KRR
AVIATION...KRR
MARINE...KRR