Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

615
FXUS61 KLWX 140109 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
909 PM EDT Sat Jun 13 2026

.WHAT HAS CHANGED...
Nothing.

&&

.KEY MESSAGES...
- 1) Severe thunderstorms return Sunday.

- 2) A return to warm and humid conditions and the potential for
  strong to severe thunderstorms Thursday.

&&

.DISCUSSION...
KEY MESSAGE 1...Severe thunderstorms return Sunday.

The dry conditions are expected to continue through the night
tonight. Overnight low temperatures are forecast to be in the
60s for most, with upper 50s in the mountains.

Conditions will turn more active during the day tomorrow. On the
synoptic scale, a shortwave disturbance will rotate around the
base of the broad upper low located to our north, tracking
through the Ohio Valley. As this shortwave approaches, the low-
level mass response ahead of it will draw deeper moisture
northward into our area within southerly flow. Dewpoints will
climb into the upper 60s to around 70 while height falls
simultaneously occur aloft. The net result of the increasing
low-level moisture and cooling aloft will be increasing
instability. This instability will overlap with strengthening
wind fields aloft. The combination of increasing instability,
shear, and large scale forcing for ascent ahead of the shortwave
and an approaching cold front will lead to the development of
thunderstorms during the afternoon.

Model guidance is still showing a fair amount of spread with
respect to the finer scale details, but the general consensus is
for isolated to scattered thunderstorms to form across the area
during the early to mid-afternoon hours as large scale lift
associated with the approaching shortwave increases. CAMs
suggest that the convective mode may remain primarily cellular,
which seems plausible given deep layer shear vectors are west-
southwesterly, and have a significant component oriented
perpendicular to any prefrontal trough that may assist in
initiation. With the cellular mode, the areal coverage of storms
may end up being a bit lower than preceding days, which
featured considerable upscale growth into linear structures. The
background environment will be characterized by around
1000-2000 J/kg of MLCAPE and around 40-50 knots of effective
bulk shear, so supercells may be possible. DCAPE values around
1000 J/kg should facilitate the development of strong
downdrafts. Damaging winds appear to be the primary threat
tomorrow, with gusts of 60-70 mph possible in stronger storms.
Very warm surface temperatures and poor mid-level lapse rates
should limit the hail threat somewhat, but an isolated instance
or two can`t be ruled out, given the possibility for supercells.
The tornado threat also appears to be very low, but non-zero,
given predominantly straight hodographs with minimal low-level
shear. SPC currently has the entire forecast area outlooked in a
Slight Risk, with damaging winds being the primary threat. It
should be noted that this is a higher end Slight Risk for
locations to the east of the Blue Ridge, with the 30 percent
wind contour.

In addition to any storms that develop in the open warm sector
during the afternoon, additional showers and thunderstorms are
expected to form along the system`s cold front in the Ohio
Valley tomorrow afternoon. These storms will then track
southeastward into our forecast area during the evening hours.
The trend over time should be for these storms to weaken as they
encounter a stabilizing boundary layer, but a low-end threat
for a thunderstorm or two will continue after dark until the
system`s cold front clears the area later in the night.

Much cooler, drier, and less humid conditions are forecast for
Monday. Mostly sunny skies are expected with high temperatures
in the upper 70s to around 80, dewpoints in the upper 40s to
50s, and a northwesterly breeze.

KEY MESSAGE 2...A return to warm and humid conditions and the
potential for strong to severe thunderstorms Thursday.

A stray shower or thunderstorm could develop later in the day
Tuesday through early Wednesday, mainly east of the Blue Ridge, as
a weak warm front slides northward from the Carolinas into Virginia.
Otherwise, average temperatures for mid-June expected Tuesday,
while we see temperatures climb a couple of degrees warmer on
Wednesday behind the warm front.

This warm front will connect to an approaching low pressure system
from the west late Wednesday night and early Thursday. The low will
push near the region and drag a cold front across the region through
the day Thursday into Thursday evening. The cold front could spawn
numerous showers and a couple of strong to severe thunderstorms
Thursday afternoon and evening.

The front could drag slowly through the region Friday morning; thus,
showers and a few thunderstorms could develop and be mainly across
our southern zones into the central Chesapeake Bay.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
Southerly winds and VFR conditions are expected tomorrow
morning. Southerly winds increase tomorrow afternoon, and may
gust to around 20-25 knots. Thunderstorms are expected to
develop across the area tomorrow afternoon. Confidence is
currently low on timing at individual locations, so PROB30s for
thunderstorms have been introduced at DCA, BWI, and IAD for now.
TEMPOs or prevailing groups will likely be needed as we move
closer in time and confidence increases with respect to exact
timing. The threat for thunderstorms will gradually wind down
through the evening. Winds will shift to out of the northwest
behind a cold front tomorrow night. Gusts to around 20-25 knots
may be possible at times later tomorrow night within
northwesterly flow. VFR conditions and lighter northwesterly
winds are expected on Monday.

VFR conditions mainly expected Tuesday through Wednesday night. Any
heavy showers or a thunderstorm could briefly reduce conditions to
MVFR at the DCA, BWI and MTN terminals. Winds light becoming
southeast 5 to 10 knots Tuesday. Winds south 5 to 10 knots
Wednesday.

&&

.MARINE...
Direction of the winds will vary by location, but will
generally be out of the west to northwest over the Upper Tidal
Potomac, and out of the south over much of the Bay. Southerly
winds are expected over the waters tonight through the day
tomorrow. SCAs are in effect for all waters tomorrow into
tomorrow evening within southerly flow. Thunderstorms will
likely impact the waters tomorrow afternoon into tomorrow
evening, with SMWs likely being needed. Damaging winds will be
the primary threat, but a stray waterspout or instance of large
hail can`t be ruled out. A cold front will move over the waters
tomorrow night, shifting winds around to out of the northwest.
Additional SCAs will likely be needed in northwesterly flow
tomorrow night. Winds will remain out of the northwest on
Monday, but are expected to drop below SCA levels by mid-
morning.

No marine hazards expected Tuesday through Wednesday night.
Winds light becoming southeast 5 to 10 knots Tuesday. Winds
south 5 to 10 knots Wednesday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 11 AM to 11 PM EDT Sunday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM to 11 PM EDT Sunday for
     ANZ530>543.

&&

$$

DISCUSSION...LFR/KLW/KJP/CPB
AVIATION...LFR/KLW/KJP/CPB
MARINE...LFR/KLW/KJP/CPB