Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

417
FXUS61 KLWX 271900
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
300 PM EDT Mon Apr 27 2026

.WHAT HAS CHANGED...
Watching a few fair weather cumulus clouds drifting about areas
east of the Blue Ridge and Catoctin Mountains as temperatures
top out on either side of 70 degrees for most. There is a
somewhat conditional risk for severe thunderstorms Wednesday.
Multiple nights of frost/freeze conditions are possible late
this week into the weekend.

&&

.KEY MESSAGES...
1) Tranquil weather through tonight before turning more
unsettled with the next frontal system Tuesday into Wednesday.

2) Multiple nights of frost/freezing conditions possible late
week into the weekend.

3) Cooler and drier Thursday with additional rain chances
Friday into Saturday as a trailing disturbance passes through.

&&

.DISCUSSION...
KEY MESSAGE 1...Tranquil weather through tonight before turning
more unsettled with the next frontal system Tuesday into
Wednesday.

High pressure is firmly entrenched from New England down the
East Coast into the Mid-Atlantic as of 19Z/3PM EDT. A few fair
weather cumulus have bubbled up east of the Blue Ridge/Catoctin
Mountains with a little bit of moisture in light onshore flow.

High clouds will increase from the west tonight ahead of stormy
weather over the Midwest. These high clouds will lower and
thicken to a mid-level cloud deck leftover from severe weather
as it approaches Tuesday morning.

A residual mesoscale convective system (MCS) is expected to
approach from the Ohio Valley by daybreak Tuesday. However,
these features often track along the instability gradient toward
regions of higher CAPE. With the forecast showing stable
profiles over the local area, it is likely the bulk of this MCS
dives toward the southern Mid-Atlantic (E TN/SW VA/W NC). For
the area spanning the Alleghenies into the Shenandoah Valley,
some decaying showers and perhaps a rumble of thunder are
possible mainly during the morning hours. However, the
stability of the atmosphere should win out here with no severe
weather expected locally on Tuesday. Additional scattered
showers can be expected throughout the afternoon/evening hours
as ripples in quasi-zonal flow push through. Highs on Tuesday
are likely to remain in the 60s underneath the thick clouds.

The better chance for showers and some thunderstorms would be on
Wednesday as a brunt of the upper trough moves toward the
Eastern Seaboard. A remnant MCV will likely be wrapped up in
this larger scale trough, the timing and amplitude of which will
dictate the extent of any strong to severe weather in the Mid-
Atlantic. As is typical with these features, their finer scale
details (as well as leftover upstream convective debris) cast
uncertainty into the extent of heating/instability. Conditionally
speaking, increasing winds throughout the lower/mid troposphere
on Wednesday as this wave approaches. Large scale ascent also
increases. The most likely area for appreciable instability to
develop would be southwest of a line from roughly Elkins WV to
Ocean City MD. This area is closer to the source of low-level
moisture return, and may see some better heating southeast of
more abundant clouds and in the vicinity of a developing warm
frontal feature. Resultant thunderstorm activity may tend to
track along the warm front later in the day, again contingent
upon the extent of available instability. Some risk for gusty to
damaging winds or perhaps a tornado or two may develop, with an
even more conditional risk of hail should stronger more discrete
cells develop.

Otherwise, widespread showers are expected as the main trough
pivots overhead and a modest secondary surface low develops and
tracks across the Mid-Atlantic Wednesday afternoon and evening.
Generally speaking, rainfall should average 4 to 8 tenths of an
inch from south to north across the region. Locally higher
totals perhaps slightly in excess of an inch are possible in any
heavier thunderstorm activity. This rainfall would be beneficial
given ongoing moderate to severe drought across the area.

Activity should diminish and push eastward Wednesday night. Cold
advection in the wake of this system could send temperatures
into the mid to upper 30s for the Appalachians by Thursday
morning, with 40s to lower 50s most likely further east (warmest
along and east of I-95, with the greatest uncertainty in 40s vs.
50s for lows roughly between I-81 and I-95).


KEY MESSAGE 2...Multiple nights of frost/freezing conditions possible
late week into the weekend.

A return to below normal temperatures is expected late this
week into the upcoming weekend. Highs Thursday and Friday will
push into the upper 50s to mid 60s (40s mountains). Lows
Thursday and Friday nights will fall into the mid 30s and low
40s. Some frost is possible Thursday night, but there will be a
slow uptick in cloud cover. A more widespread frost and freeze
is possible Saturday night into Sunday morning as drier air pushes
in resulting in fewer clouds.

Weekend highs will remain in the 50s and 60s with a quick rebound
back into the 70s early next week as high pressure builds over the
southeast U.S.


KEY MESSAGE 3...Cooler and drier Thursday with additional rain
chances Friday into Saturday as a trailing disturbance passes
through.

Broad high pressure over the central Plains will slide eastward
toward the Tennessee/Ohio River Valleys Friday into Saturday.
Meanwhile, departing closed low pressure will eject north and east
along the New Jersey/Long Island coast late Thursday before ejecting
toward the northern New England coast Saturday and Sunday.

Additional spokes of energy will pivot around the back side of this
low bringing additional shower chances to the region Friday and
Saturday. This is illustrated in the GFS, EURO, and GEM along with
their ensembles. The deterministic GFS is the most amplified
and aggressive with potential coastal low development, but has
little support from other numerical guidance at this point.

The coverage of showers may ultimately be isolated to scattered
in nature with a focus mainly where better forcing resides.
There may even be a period of snow across the Alleghenies late
Friday into Saturday as colder air rushes in. Any accumulations
will be confined to the highest elevations (above 3500 feet)
with no impact expected at this time.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A few cu may linger tonight as high clouds increase from the
west. VFR conditions will persist through tonight. This comes
with a light wind that shifts from east/northeasterly over to
southeasterly through the night.

In response to the next system, showers and perhaps some
thunderstorms (especially Wednesday) will yield some
restrictions at times over the next couple of days. NAM/GLAMP
favor lower CIGs to IFR developing during the day Tuesday, but
am skeptical in CIGs getting that low given a drier start, only
light onshore flow, and increased diurnal mixing. A soaking
rain is looks more likely for Wednesday which would favor a
more prolonged period of sub-VFR conditions. Wind fields
largely vary between southerly and southeasterly through
Wednesday, with afternoon gusts to around 15 to 20 knots. An
eventual shift to westerly is expected by Wednesday night
behind the frontal system.

Prevailing VFR conditions are expected Thursday and Friday as high
pressure slowly returns to the region. A few rain showers could
accompany a fast-moving disturbance Friday into Saturday, but
overall confidence in coverage and intensity is low at this
time. Some sub-VFR conditions are possible at times during this
period. Winds will turn to the northwest Thursday with gusts 20
to 25 kts. Winds will decrease Thursday night into Friday with
gusts around 15 to perhaps 20 kts. Northwest winds continue
Saturday with gusts up to 20 kts possible.

&&

.MARINE...
Light east winds and a clear sky are expected through tonight.
There may be a brief easterly push of wind gusts around 15 to
perhaps 20 kts for an hour or two heading into this evening
roughly between 8 and 11 PM.

Otherwise, gradients remain weak through Wednesday morning
which will keep winds below advisory thresholds. The next ramp
up would be Wednesday afternoon ahead of an approaching cold
front. A strengthening southeasterly wind will likely require
Small Craft Advisories for Wednesday afternoon through the
night. By the overnight hours, gusts up to 25 knots or so are
possible before winds shift to the west. Showers and a few
thunderstorms are anticipated during this time.

Small Craft Advisories are likely Thursday through Saturday
night. Winds northwest 15 to 20 knots (gusts 25 knots) Thursday,
then northwest around 15 knots (gusts 20 to 25 knots) Thursday
night through Saturday.

&&

.TIDES/COASTAL FLOODING...
Onshore flow continues as high pressure moves off the New
England coast and waves of low pressure approach from the west.
Many locations will reach Action Stage during high tide through
Wednesday, with Minor tidal flooding possible especially at
Annapolis and Dahlgren. A couple other tidal sites like
Alexandria and Havre de Grace could get close during the higher
of the two astronomical high tides, as well.

&&

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

&&

$$

DISCUSSION...BRO/DHOF/EST
AVIATION...BRO/DHOF/EST
MARINE...BRO/DHOF/EST