Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

596
FXUS61 KLWX 020803
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
403 AM EDT Sun Aug 2 2026

.WHAT HAS CHANGED...
A Flood Watch has been issued for parts of the area through
tonight. A Coastal Flood Advisory has been issued for Anne
Arundel County where minor tidal flooding is expected at
Annapolis.

&&

.KEY MESSAGES...
- 1) Locally heavy rainfall could lead to instances of flash
  flooding this afternoon into tonight.

- 2) Sustained shower and thunderstorm chances continue through
  the end of the week.

&&

.DISCUSSION...

KEY MESSAGE 1...Locally heavy rainfall could lead to instances
of flash flooding this afternoon into tonight.

A large upper trough over the western OH Valley this morning is
progged to slowly move east toward the Mid-Atlantic through the
early part of this week. While the main mid-level energy of this
system will pass by north of our area on Monday, a trailing wave of
vorticity will stretch south along the Appalachians into the Deep
South. A weaker cutoff mid-level low develops somewhere near the
southern Appalachians Monday night. An associated surface boundary
moves into the northern half of the area tonight, then stalls nearby
through at least Tuesday before possibly lifting north as a warm
front. To our east the Bermuda High remains squarely in place across
the western Atlantic. Southerly flow is advecting deep tropical
moisture into the Mid-Atlantic today, with PWATs well over 2".

Light to moderate showers have already started moving into the area
early this morning. A heavier line of showers over West Virginia is
likely to reach the Alleghenies after sunrise. Many additional
rounds of showers and thunderstorms are expected to develop through
tonight. The very moist environment will favor abundant low clouds
which result in lower instability values, though cloud breaks could
produce some areas of additional destabilization. SPC has maintained
the Marginal Risk (level 1 of 5) for severe thunderstorms today.
Given the saturated environment, water-loaded downdrafts capable of
strong winds are going to be the main severe threat.

The likely higher threat is going to be the potential for flash
flooding. Areas that see multiple rounds of heavy showers and
thunderstorms will be most at risk, especially urban and poor
drainage areas. A Flood Watch has been coordinated with the
surrounding offices for areas along the Blue Ridge, central
Shenandoah Valley, and Alleghenies.

For the Alleghenies, the time period of highest concern is likely
this afternoon as the frontal boundary moves into the area. Given
the orientation of the boundary and how storms will progress along
it (from southwest to northeast), there is the potential for
training thunderstorms. A similar, though lower confidence scenario,
could play out in the central Shenandoah Valley and along the Blue
Ridge. Terrain enhanced convection could produce localized higher
rain amounts on the eastern slopes of the ridge. Overall, rain
amounts of 1-2" are likely, with localized higher amounts of 3-4"
possible.

For the DC and Baltimore Metro areas, there is concern for flooding
as multiple rounds of showers/thunderstorms move through late this
afternoon into tonight. However, confidence remains low regarding
exactly where any heavier thunderstorms develop. We will continue to
analyze new model data this morning, so it is possible the Flood
Watch is extended east into the metro areas. Showers and a few
thunderstorms likely persist well into tonight, especially east of
the Blue Ridge.


KEY MESSAGE 2...Sustained shower and thunderstorm chances
continue through the end of the week.

For the start of the work week shower and thunderstorm chances
continue each afternoon and evening as we sit within the warm
sector. Meanwhile, waves of low pressure will continue to pivot
through as a stalled boundary sits just south and east of the area.
Additional concerns for flooding may develop as the week progresses.

Daily shower and thunderstorm chances continue through the end of
the week as an upper level low stalls over the Appalachians before
slowly tracking eastward. As this system finally pushes offshore
towards the end of next week, the lingering frontal boundary could
produce potentially increased chances for severe weather. Medium-
range machine learning outputs show an enhanced possibility between
Thursday and Saturday as this system transitions offshore. As PWATs
will remain elevated during this period (ranging between 1.5-2.1
inches), heavy rainfall as well as gusty to damaging winds will be
likely hazards with any severe storms that do form. Given persistent
ongoing drought within the region, flood threats will likely be
isolated to poor drainage areas during any periods of sustained
heavy rain.

As this system stalls just south of the region during the week,
temperatures will slowly increase and, combined with increased
humidity during this period, could bring back elevated heat indices
in the upper 90s across the metros beginning Wednesday. High
pressure moves in overhead once any lingering frontal boundaries
push offshore.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Sub-VFR conditions are likely to develop by this evening across the
areas as low clouds slowly settle over the region. Showers are
already moving in this morning, with multiple rounds of heavy
showers and thunderstorms expected this afternoon to evening. TEMPO
groups have been added to most of the TAFs, though there is still
uncertainty regarding exact timing for the worst impacts. A period
of steady showers is expected this evening into the first half of
tonight.

While some improvements are likely by Monday morning, the stalled
frontal boundary over the region will maintain low clouds and
passing showers. Additional rounds of afternoon to evening
thunderstorms are likely each day.

Sub-VFR conditions will likely continue to be intermittent at
terminals throughout the week as daily shower and thunderstorm
chances persist, particularly in the afternoon & evening timeframe.
South to southwesterly winds flow Wednesday and through the end of
the week.

&&

.MARINE...
Southerly flow across the waters is producing SCA conditions early
this morning. Expect winds to remain elevated through tonight, then
slowly taper off by Monday morning. Multiple rounds of heavy showers
and thunderstorms will move across the waters this afternoon to
evening. Special Marine Warnings may be needed for thunderstorms
capable of producing wind gusts in excess of 35 knots. While winds
are likely to remain below SCA levels Monday and Tuesday, there will
be additional afternoon to evening thunderstorms each day.

Southerly channeling over the waters could produce SCA conditions in
the afternoon/evening hours both Wednesday and Thursday. A few
showers & thunderstorms are possible over the waters during this
period due to a stalled front nearby.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies continue to rise, with sensitive locations reaching
Action Stage to minor flood stage this morning. A Coastal Flood
Advisory has been issued for Annapolis. South winds are forecast to
persist for much of the week, so additional periods of coastal
flooding are possible.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 8 AM EDT Monday for MDZ008.
     Coastal Flood Advisory until 10 AM EDT this morning for MDZ014.
     Flood Watch from 10 AM EDT this morning through late tonight
     for MDZ501-502-509-510.
VA...Flood Watch from 10 AM EDT this morning through late tonight
     for VAZ503-504.
     Flood Watch from 2 PM EDT this afternoon through late tonight
     for VAZ025>027-029-036>040-507-508.
WV...Flood Watch from 10 AM EDT this morning through late tonight
     for WVZ050-055-501>506.
MARINE...Small Craft Advisory until 8 AM EDT Monday for ANZ530>534-
     537>543.
     Small Craft Advisory until 11 PM EDT this evening for ANZ535-
     536.

&&

$$

DISCUSSION...KRR/SRT
AVIATION...KRR/SRT
MARINE...KRR/SRT