Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

225
FXUS61 KLWX 200734
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
334 AM EDT Sat Jun 20 2026

.WHAT HAS CHANGED...
Small Craft Advisories were expanded to cover all the waters
today.

&&

.KEY MESSAGES...
- 1) A few severe thunderstorms and locally heavy rainfall are
  possible Monday after a seasonable and less humid weekend.

- 2) Slightly drier conditions Tuesday and Wednesday with an
  active weather pattern returning late week into the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...A few severe thunderstorms and locally heavy
rainfall are possible Monday after a seasonable and less humid
weekend.

The overall theme for the weekend will be seasonable weather (if
not a touch on the cool side, especially at night) along with
low humidity. Breezy conditions are expected again today
between high pressure building south of the area and another
secondary front approaching from the north. The associated
shortwave trough may spark scattered showers and perhaps a
thunderstorm upstream again during the day. The Allegheny
Mountains are most likely to be affected by these showers,
although some guidance shows a few showers or sprinkles
continuing east across the rest of the forecast area as well.
Sunday will trend a little warmer.

The next low pressure system will move into the Ohio Valley
Sunday night, then pass near or north of the area Monday. The
low will then either progress or redevelop off the coast Monday
night. There is still some model spread regarding the evolution
of the low and how quickly the associated warm front lifts
north. Rain chances will increase Sunday night as the warm front
approaches, but it is uncertain whether it`s more of a glancing
shot, or if more widespread showers persist into the day Monday
(owing toward a more southern solution). If the warm sector can
advance solidly into the area and allow for some clearing,
strong to severe thunderstorms could develop as the low and cold
front cross during the afternoon and evening. While some locally
heavy rain could occur either way with the thunderstorms due to
precipitable water approaching 2 inches, a scenario where the
warm front stalls overhead would lead to higher rain totals and
at least a low end threat of localized flooding (the Weather
Prediction Center has a Marginal Risk for excessive rainfall).
Secondarily, ensembles also show a wide range of temperatures
depending on the position of the front. Any rain should be
exiting the area by the second half of Monday night.


KEY MESSAGE 2...Slightly drier conditions Tuesday and Wednesday with
an active weather pattern returning late week into the weekend.

Not too much of a change as we enter more of a typical Summertime
regime for the extended forecast period. Looking at a lull in the
shower and thunderstorm activity Tuesday and Wednesday as weak high
pressure builds in the wake of a departing cold front. Beyond
Wednesday, is where the forecast gets a bit more uncertain as the
upper level trough will remain firmly entrenched across the area.
6z/12z guidance continues to show some subtle difference in regards
to a wave of low pressure and cold front late week. Some of the
guidance leans toward a frontal passage Thursday into Friday while
low pressure races into the northern New England and Canadian
Maritimes. Other pieces of guidance have a front passing Thursday
before stalling south of the area Friday into the weekend. In
addition to this, a secondary wave of low pressure will eject out of
the northern Plains/northwestern U.S providing a condition of active
weather into the weekend.

As a result, expect daily afternoon and evening thunderstorm chances
Thursday into the upcoming weekend. Coverage and intensity have yet
to be determined based upon the timing and placement of synoptic
features in play. Any rain that we do see will be beneficial given
continued drought concerns. With multiple frontal passages and daily
precipitation chances expect temperatures to remain at or just above
normal through the region. Highs will push into the into the upper
70s and mid 80s (low 70s mountains) with overnight lows in the upper
50s and low 60s. Humidity will also start to increase especially
during the late period.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
High pressure will provide dry weather through the weekend. Gusty
west to northwest winds are expected again from late this
morning into the afternoon with gusts up to 25 kt. If skies are
clear, some patchy fog could form near MRB tonight. Winds will
be lighter Sunday.

Showers and thunderstorms appear likely Monday, some of
which could be strong to severe with heavy rain. Outside of
storms, southerly winds could gust to 25 kt assuming a warm
front clears the area to the north.

VFR conditions are expected Tuesday and Wednesday as the cold front
departs the region. An isolated shower or thunderstorm cannot be
ruled out with northwest winds Tuesday (less than 15 kts) becoming
light and variable midweek. Additional sub-VFR conditions are
possible Thursday as another strong front crosses the region.

&&

.MARINE...
Gusty west to northwest winds will return later today. A Small
Craft Advisory has been issued for portions of the northern bay
and upper tidal Potomac where confidence is highest. However,
it`s possible this advisory may need to be expanded in the
future. Lighter winds are expected tonight into Sunday.

Southerly winds will increase Sunday night into Monday,
depending on how quickly a warm front lifts north. Advisories
will likely be needed. Strong to severe thunderstorms are also
possible during the afternoon and evening in advance of a cold
front. Advisories may be needed in the northwest winds in the
front`s wake.

SCA conditions will likely linger through Tuesday afternoon before
the gradient relaxes Tuesday night into Wednesday as weak high
pressure builds in. Brief southerly channeling is possible over the
middle and lower waters of the bay and lower waters of the tidal
Potomac Thursday afternoon into Thursday night. In addition, showers
and thunderstorms will be possible Thursday afternoon.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 11 AM this morning to 8 PM EDT this
     evening for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM this morning to 8 PM EDT this
     evening for ANZ530>543.
     Small Craft Advisory until 6 AM EDT early this morning for
     ANZ531>534-537-539>541-543.

&&

$$

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