Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

354
FXUS61 KLWX 041938
AFDLWX

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

.WHAT HAS CHANGED...
Have increased shower chances across the I-64 corridor given
ongoing radar trends. Otherwise, the 12Z high-resolution models
are still not completely on board with an excessive rainfall
threat tonight into early Wednesday. However, with increasing
moisture content coupled with an approaching warm front, the
risk does appear non-zero tonight which bears monitoring.

&&

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

- 2) Daily shower and thunderstorm chances are expected from
  Wednesday into early next week.

&&

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

While the earlier frontal boundary is currently down in southern
Virginia, broad ascent atop this frontal zone is yielding
multiple areas of convection. The latest KLWX WSR-88D radar
imagery depicts one such wave bringing some light showers to
areas just north of I-64 in central Virginia. Being at the
leading edge of the instability gradient, this storm cluster is
not terribly organized and has continued to weaken. However, in
the wake of these storms, a more concentrated axis of heavier
showers and thunderstorms have begun to develop around the
Richmond metro area. These are slow moving and already yielding
Flash Flood Warnings in central Virginia. Looking further south,
additional slow moving cells are forming over the Virginia
Tidewater region. As the warm front lifts northward in time, all
of this convection shifts focus toward the local area by
tonight into early Wednesday morning. How this evolves over the
next 6 to 12 hours will dictate the degree of impact to the
region.

Besides the showers moving near/just east of Charlottesville,
the weather has been tranquil across the remainder of the area.
Aside from some shallow fair weather cumulus fields, skies
remain mostly sunny this afternoon. Being north of the frontal
zone, mean surface winds are largely out of the east to
northeasterly direction. Overall temperatures are holding steady
in the low/mid 80s, with mainly 70s across mountain locales.
This comes with dew points in the 60s which are supporting heat
indices in the mid 80s to low 90s. Expect clouds to increase
into tonight as the warm front lifts poleward. Forecast lows
will be in the 60s to low 70s, with increasing shower chances.

Looking a bit more closely at the threat for overnight heavy
rainfall, the 12Z high-resolution models are not showing the
strongest of signals. However, there are a number of
meteorological conditions which warrant this situation to bear
watching. This includes: (1) Precipitable water values (PWAT)
increasing from 1.50 to around 2 to 2.25 inches, (2) An uptick
in warm advection with the approaching front, and (3) Enhanced
lift with vorticity swinging northward from an upper low across
the Mid-South. Where the heavy rainfall sets up will dictate the
degree of impact. If this impacts the urban sprawl around the
D.C. metro, poor drainage will support a risk of flash flooding.
Will continue to monitor the situation and 00Z/18Z guidance to
determine if any Flood Watches will be needed.


KEY MESSAGE 2...Daily shower and thunderstorm chances are
expected Wednesday into early next week.

In the wake of what morning convection materializes, the models
do show a brief lull in the action. The northward pushing warm
front eventually stalls nearby before shearing out. Likewise,
the upper low across the Mid-South region begins to fill
although the reflection of this circulation still shows up
across southern West Virginia on Wednesday. Remaining
perturbations around this mid/upper low should help fire off
some afternoon/evening thunderstorms. A number of models depict
anomalous moisture lingering across the region with PWATs over 2
inches for those of the Blue Ridge. While no clear signal
exists, slow moving cells could produce a few instances of flash
flooding. However, the longstanding drought conditions could
easily curb that threat.

Seasonably warm temperatures and typical early August humidity
remain a fixture in the forecast for the foreseeable future. A
broad subtropical ridge in the mid/upper levels will continue
retrograding from the western Atlantic back toward the Eastern
Seaboard. At the same time, while the strongest jet energy
remains tied to the northern tier states, the quasi-zonal flow
aloft will steer a myriad from weak to modest shortwaves toward
the northeastern U.S. As usual, these types of features are of
low confidence given the mesoscale nature of the convective
elements. As such, will continue to maintain a risk of strong to
severe thunderstorms as well as isolated instances of flash
flooding each day. At this point, Friday presents the most
active looking day of the period. However, this could easily
change as global models continue to waver from run to run.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Showers continue to weaken while pushing to the vicinity of
KCHO. Given closer proximity to the frontal zone, activity near
Richmond is likely to impact the Charlottesville area first.
This TAF site should bring the most likely period for
restrictions as storms move in from the southeast. Elsewhere,
VFR conditions continue through the evening and early overnight
hours. This is accompanied by mainly light easterly winds.
However, lowering ceilings will support restrictions across all
terminals tonight into Wednesday morning. Locally heavier
rainfall could impact the D.C. metro area terminals. Some
improvements are expected by midday before another round of
storms could impact the area. PROB30 groups accompany this
threat, particularly in the 20Z-00Z window on Wednesday.

Winds shift to mainly south to southwesterly for the foreseeable
future as a Bermuda high pressure system persists across the
western Atlantic. Daily convective chances each afternoon and
evening will support convective-driven restrictions. With little
change in the upcoming pattern, this sort of forecast will
likely hold for the next several days.

&&

.MARINE...
While today largely presents tranquil weather across the
waterways, this will change for the mid to late week period.
Diurnally driven showers and thunderstorms should increase the
risk of hazardous conditions for boaters and swimmers. Special
Marine Warnings would accompany any of the stronger storms, with
any cell capable of producing frequent lightning and gusty
winds. In terms of gradient winds, a few periods of southerly
channeling may warrant some short-fused Small Craft Advisories.
Most notably, this would include Wednesday evening into
Thursday, as well as Friday evening into the night.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies continue to remain on the lower end as northeast
to easterly winds persist. 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...None.

&&

$$

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