Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

430
FXUS61 KLWX 110000
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
800 PM EDT Tue Mar 10 2026

.WHAT HAS CHANGED...
No significant changes have been made to the forecast. Please
stay weather aware for Wednesday as severe weather is possible.

&&

.KEY MESSAGES...
- 1) Severe Thunderstorms are possible Wednesday afternoon and
  evening.

- 2) Well above normal temperatures through Wednesday
  afternoon.

- 3) A series of cold fronts crossing the area into early next
  week will lead to multiple temperature swings.

&&

.DISCUSSION...
KEY MESSAGE 1...Severe Thunderstorms are possible Wednesday
afternoon and evening.

Tomorrow`s forecast is an extremely challenging one. At this point,
there`s a wide range of potential solutions on the table, with very
low confidence in which solution will ultimately verify. Forecast
details follow below...

A potent northern stream trough will continue to amplify as it
tracks eastward from the Northern Plains toward the Great Lakes
during the day tomorrow. A corresponding surface low will deepen as
it tracks northeastward from Lower Michigan across the Lower Great
Lakes and into the St. Lawrence Valley. The low-level mass response
to the deepening cyclone will lead to strengthening low-mid level
winds, as a 700 mb jet of 50-70 knots develops over the Ohio Valley
tomorrow morning, and then spreads northeastward over our forecast
area by peak heating tomorrow afternoon. Southerly flow at low-
levels will draw deeper moisture (low 60s dewpoints) northward into
the area, which when combined with daytime heating (surface temps
climbing into the upper 70s and lower 80s) will lead to surface-
based destabilization (MLCAPE values around 500-1500 J/kg). Assuming
that storms occur, the environment in place with MLCAPE values of
500-1500 J/kg and effective bulk shear values of around 50 knots
(with nearly all of it below 700 mb) will be very favorable for the
development of severe thunderstorms. However, many questions remain
with respect to the coverage of storms, the storm mode, hodograph
shape, and resultant storm impacts locally.

00z/12z CAM guidance is in good agreement that there will be plenty
of ongoing convection tonight upstream in the Ohio Valley. Some of
this activity will likely impact the West Virginia Panhandle,
western Maryland, and potentially north-central Maryland tomorrow
morning. Much of this activity will likely be elevated in nature,
but some heavier downpours, lightning, and maybe even a little small
hail may be possible during the morning hours as this activity moves
through. Further south and east, conditions will likely remain dry
through the morning, with daytime heating occurring through a broken
cloud deck.

Forecast uncertainty increases moving into the afternoon hours, with
various sources of model guidance advertising a wide array of
potential solutions. On one extreme lies the 3km NAM, which fails to
produce any additional storms after the elevated activity moves
through during the morning. Inspection of 3km NAM forecast soundings
shows strong capping, which in turn inhibits the development of new
storms. A tendency toward under-mixing and overcapping is a well
known forecast bias of the 3km NAM. In this type of scenario, there
would be no severe weather threat across the bulk of the forecast
area tomorrow. A potential exception would be with any remnant
squall line moving into the Alleghenies from the Ohio Valley
tomorrow evening. On the other end of the spectrum lies the HRRR,
which produces numerous additional storms during the afternoon and
evening hours. Most of these storms actually form upstream in the
Ohio Valley during the morning and persist into the forecast area
during the mid afternoon to evening hours. Inspection of HRRR
forecast soundings shows much deeper mixing, which is unsurprising,
since overmixing/undercapping is a known bias of the HRRR. In terms
of storm mode, the HRRR solution shows both supercells and smaller
bowing segments.

Other sources of guidance lie somewhere between these scenarios. The
Hi-Res Canadian falls into the 3km NAM camp, keeping things capped
and producing no additional storms locally. The FV3 is the next
lowest in terms of storm coverage, only producing a few isolated
cells, primarily across northern Maryland and northern portions of
the West Virginia Panhandle. The RRFS also keeps activity
predominantly confined to northern WV/MD, but more in the form of an
organized squall line. The WRF-ARW develops a much larger
QLCS/squall line with embedded bowing segments out of pre-exisiting
convection that emanates out of southern WV. In that scenario, the
QLCS would impact most of the forecast area. The WRF-NSSL is much
different than any of the above solutions, tracking a strong,
elevated QLCS across northern MD during the morning hours, which
lays out an east-west oriented outflow boundary. Then in the
afternoon, it has a string of intense, isolated supercells
developing along the differential heating boundary produced by
the outflow, which then track eastward across northern Maryland.

Beyond the differences in convective evolution/mode, there are also
significant hodograph shape differences between the models. More
overmixed models like the HRRR show close to straight hodographs,
while undermixed models like the 3km NAM show much more hodograph
curvature. The WRF-NSSL shows the greatest hodograph curvature of
all, as a result of the remnant outflow boundary.

The uncertainty with respect to convective mode and hodograph
curvature cascades into uncertainty with regard to the potential
hazards as well. The environment in place will make damaging winds
possible with any storms that form. However, that threat would
likely be maximized in scenarios that produce a more linear
convective mode, with a QLCS or smaller bowing segments. A more
cellular mode would likely lead to supercells, a greater threat for
both severe hail and tornadoes, and lesser areal coverage of
damaging winds compared to a linear mode. At the moment SPC has most
of the area outlooked in a Slight Risk, driven by damaging wind
potential. They also have a 5 percent hail contour, and 2/5 percent
tornado contours, along with a CIG 1 hatching (suggesting a
reasonable maximum tornado intensity of EF-2, if a tornado were
to occur). The CIG1 hatching hints at the higher end potential
of the severe threat tomorrow. There is no CIG 1 hatching for
wind tomorrow, but hurricane force gusts (74+ mph) are needed to
justify wind hatching. It wouldn`t be a shock to see some 60-70
mph gusts in any bowing segments, if storms do occur.

With the high level of forecast uncertainty, following observations
will be critical over the next 24 hours. The level of mid-level
capping, along with how upstream convection over the Ohio Valley
evolves will be critical factors in determining what ultimately
occurs here tomorrow.

A brief summary of the main takeaways follows below:

-Forecast uncertainty is very high tomorrow. Plausible scenarios
range from no severe thunderstorms at all, to a very impactful
severe thunderstorm event.

-Confidence in elevated storms impacting the WV Panhandle/western MD
tomorrow morning is high, but those storms likely won`t pose much of
a severe threat.

-Any storms that do form tomorrow afternoon will likely turn severe,
posing at least a threat for damaging winds, and potentially large
hail and tornadoes too (if the storm mode is supercellular).

-The timing of the most intense storms is expected to be in the
afternoon and evening hours, with the strongest storms (if they
occur at all) expected to move through the I-95 corridor between
roughly 3 and 8 PM.

-A squall line will likely approach from the Ohio Valley and
 track toward the Alleghenies tomorrow evening, but will likely
 be weakening as it does so. Any severe threat with this line
 will likely stay confined to along/west of the Allegheny Front.


KEY MESSAGE 2...Well above normal temperatures through
Wednesday afternoon.

Very warm temperatures again Wednesday afternoon with
temperatures in the upper 70s to lower 80s. Dry conditions as
well for Wednesday morning and perhaps around midday with plenty
of sunshine.

Record high temperatures may be in jeopardy and could very well
be reached Wednesday afternoon as this day should be the
warmest day. Some daily temperature records look possible (see
Climate section below for more information). This is ahead of a
powerful cold front, which will bring a substantial change to
the weather thereafter.


KEY MESSAGE 3...A series of cold fronts crossing the area into
early next week will lead to multiple temperature swings.

Temperatures take a 15 to 30 degree dive Thursday as gusty west
to northwest flow ramps up. Confidence is a bit higher here for
the wind given the residual gradient/high pressure returning
from the south. A non-diurnal temperature spread is expected
with highs ranging from the upper 30s over the mountains to
upper 50s along and east of I-95.

A progressive mid-latitude pattern will allow a myriad of short and
longwave troughs to trek across the country. Such a regime supports
marked temperature swings as the associated cold fronts push toward
the Eastern Seaboard. The peak in the warmer phase of this pattern
would be on Sunday before temperatures come crashing down into next
week.

A compact upper trough pushing across the Great Lakes toward eastern
Canada will carry a deep cyclone with it. Global guidance keep the
low track mainly near/north of the international border with Canada.
Given how far the forcing is from the local area, expect a few
showers across the Alleghenies on Friday, but otherwise most of the
area remains dry. The robust wind field with the trough will make
for breezy conditions on both Friday and Saturday. Given the higher
winds are aloft, the strongest gusts should be confined to mountain
locales.

There has been a trend in the guidance toward warmer conditions for
Sunday as highs rise well into the 60s. However, an even more
pronounced system swings across the eastern U.S. late Sunday into
early next week. In response, global ensemble solutions show a
marked fall in temperatures. This brings a return to more winter-
like conditions for the early/mid portions of next week.

&&

.AVIATION /00Z TUESDAY THROUGH SUNDAY/...
VFR conditions expected through Wednesday midday. Winds will
remain light to moderate out of the south to southwest. Some
patchy fog is possible tonight as more warm and moist air moves
in.

A strong cold front will bring the return of sub-VFR conditions
Wednesday afternoon into Thursday. Showers and strong to severe
thunderstorms look to impact the terminals during this time.
Some storms could be severe Wednesday afternoon/evening, with
damaging winds and large hail being the main threats. An
isolated tornado or two cannot be ruled out as there will be
plenty of wind shear. There remains some uncertainty with
regards to coverage of storms, so that will be the main question
mark in the forecast at this time.

Outside of the shower and thunderstorm threat will be the wind.
Expect gusty south to southwesterly winds up to 25 kts Wednesday
switching to the northwest with gusts 25 to 35 kts Thursday
afternoon.

Expect largely VFR conditions on Friday into Saturday with any
precipitation threats to the west of all TAF sites. The bigger story
will be the gusty winds on Friday ahead of another strong cold
front. Ahead of this system, expect southerly gusts to around 25 to
30 knots before winds shift to west-northwesterly into Saturday.

&&

.MARINE...
Sub-SCA winds prevail with light to moderate south to southwest
winds through early Wednesday.

SCA conditions are possible in southerly channeling midday
Wednesday into Wednesday night. Gusts of 20 to 25 kts are
possible, especially over the open and middle waters of the
Chesapeake Bay/tidal Potomac River. This will become
increasingly likely by Wednesday evening, with more marginal
chances during the day.

A strong cold front will cross the waters late Wednesday night into
Thursday. This will lead to a few gusty showers/t-storms (SMWs
may be needed as these push through) and gusty post-frontal
north to northwest flow. Gusts of 25 to 35 kts can be expected
with even some northerly channeling over the northern Chesapeake
Bay. Winds will gradually decrease Thursday night into early
Friday morning.

Ahead of a strong cold front, southerly channeling effects will lead
to increasing wind fields across the area waterways. Gusts up to
30 to 40 knots are possible on Friday, especially over the
Chesapeake Bay. Small Craft Advisories will be needed for Friday
into Friday night, with Gales possible.

Winds diminish some behind the front with mainly west-
northwesterlies on Saturday.

&&

.CLIMATE...
Daily high records were tied or set this afternoon, and could be
set again Wednesday.

Below is a list of previous records for March 10 and 11.

Washington DC (DCA)
Date                March 10    March 11
Record High         79F/2016    79F/2021
Record Warm Low     57F/2016    57F/2016

Washington-Dulles (IAD)
Date                March 10    March 11
Record High         80F/2016    79F/2021
Record Warm Low     59F/2016    49F/1967

Baltimore (BWI)
Date                March 10    March 11
Record High         80F/2016    79F/2021
Record Warm Low     57F/2016    53F/1955

Annapolis (NAK)
Date                March 10    March 11
Record High         78F/2016    74F/1967
Record Warm Low     56F/2020    52F/1986

Charlottesville (CHO)
Date                March 10    March 11
Record High         80F/2016    83F/1925
Record Warm Low     58F/2020    53F/2016

Martinsburg (MRB)
Date                March 10    March 11
Record High         80F/2016    78F/2021
Record Warm Low     53F/2016    49F/1955

Hagerstown (HGR)
Date                March 10    March 11
Record High         80F/2016    79F/2021
Record Warm Low     57F/2016    53F/2016

Baltimore Inner Harbor (DMH)
Date                March 10    March 11
Record High         82F/2016    76F/1967
Record Warm Low     60F/2016    56F/2016
                56F/1955

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

DISCUSSION...BRO/KLW/DHOF/CJL/KJP
AVIATION...BRO/KLW/DHOF/CJL
MARINE...BRO/KLW/DHOF/CJL