Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

021
FXUS61 KLWX 171959
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 PM EDT Wed Jun 17 2026

.WHAT HAS CHANGED...
Added scattered sprinkles/isolated showers to northern areas this
afternoon as shallow instability and weak convergence have resulted
in some radar returns.

Wind Advisory issued for portions of the Allegheny Mountains
Thursday. This may need to be expanded to some of the other high
elevation zones. Overall the wind forecast was nudged upward area-
wide, and the potential for gale conditions on portions of the
waters will continue to be assessed.

Coastal Flood Advisories issued for Annapolis and Havre de Grace
Thursday morning.

&&

.KEY MESSAGES...
- 1) Hotter conditions return Thursday with potential for severe
  thunderstorms and strong gradient winds.

- 2) A strong low pressure system could bring the threat for
  heavy rainfall and thunderstorms late Sunday through Monday.

- 3) An active upper-level pattern could bring continued rain
chances through mid-week.

&&

.DISCUSSION...
KEY MESSAGE 1...Hotter conditions return Thursday with potential
for severe thunderstorms and strong gradient winds.

An anomalous low pressure system for June is forecast to track
across the Great Lakes tonight and into central Quebec Thursday.
The associated cold front will push south through the forecast
area Thursday afternoon into Thursday night. Attendant to this
low will be a very strong wind field, with the strongest low
level jet forecast to cross the area during the morning before
retreating to the northeast during the afternoon.

Heat: A hotter airmass will quickly advect over the area Thursday.
Good mixing and a downslope component to the wind will result in
temperatures pushing into the 90s for many locations (assuming
clouds aren`t too persistent). While it will be more humid than the
past couple days, dew points should mix down during peak heating,
resulting in heat index values in the mid 90s to perhaps near 100.

Wind: The strong wind field combined with good mixing of southwest
to west winds will result in breezy conditions through the day.
There are two windows of potentially stronger winds. If mixing
occurs quickly enough in the morning, some of the low level jet will
be able to mix down. Then in the afternoon, pressure rises behind
the front (or at least a more aligned with height westerly winds in
the wake of the lee trough) combined with a tightening pressure
gradient could result in some stronger winds, especially in
northwestern parts of the area. A Wind Advisory has been issued for
Garrett and western Grant Counties, which will be both closer to the
stronger wind fields as well as see frontal passage in the
afternoon. The advisory may need to be expanded to more high
elevation zones based on additional data, though clouds and remnant
showers may limit mixing of the LLJ during the morning. Elsewhere
across the area, 25-40 mph gusts will be common throughout the day.

Severe thunderstorms: The thunderstorm threat for Thursday remains
uncertain due to competing factors and upstream impacts. The
evolution of thunderstorms across the Midwest today/tonight may have
an impact on what develops across the local area on Thursday. Many
models have some sort of remnant convection reaching the Allegheny
Mountains around dawn, likely weakening significantly in the
process. If the storms don`t dissipate entirely, the remains or
outflow could reignite along the surface trough to the east
during peak heating. If convective perturbations are more
absent, it`s possible clouds could inhibit instability
development. In addition, the downslope (drying/subsidence)
component to the winds could cap convection as well. However,
more models are showing at least isolated to scattered
development, especially ahead of the surface trough (roughly
splitting the forecast area NE to SW) during the afternoon
hours. While the LLJ will pivot away by this time, there will
still be plenty of shear and enough instability for organized
thunderstorms producing a damaging wind threat, especially given
the DCAPE available. Localized considerable wind damage can`t
be ruled out. Most of the storms should exit the area by early
to mid evening.

The cold front will push southward Thursday night. The front will
absorb an area of low pressure to the south, likely originating from
Arthur. There is still some spread with how far north additional
rain reaches, but some rain chances will linger across the southern
half of the area in particular through Friday morning. Skies should
clear through the day with lowering humidity and seasonable
temperatures.


KEY MESSAGE 2...A strong low pressure system could bring the threat
for heavy rainfall and thunderstorms late Sunday through Monday.

After a quiet weekend, the upper-level pattern becomes quite
amplified by late Sunday. However, there are a lot of moving pieces
of upper-level energy to keep track of when it comes to determining
how our area might be impacted. There is growing confidence in a
fairly potent area of low pressure developing somewhere across the
northern/central Plains on Sunday, before moving into the OH
Valley/Great Lakes region into Monday. The big question is going to
be where the storm actually tracks. Right now all hazards are at
play with this system, ranging from severe thunderstorms to
potentially flooding rainfall depending on the track. This system
may be working with a connection to the Gulf of America, with 1.5 to
2+ sigma PWAT anomalies, so there will be some substantial moisture
to work with. Our area has been in a pretty longstanding drought
though, so in a best case scenario, perhaps this system bring mostly
beneficial rainfall to some very dry areas. Again, this is a very
complex upper-level pattern that is hard to nail down at this stage,
but it is worth noting that this could be the next potentially
hazardous weather system.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR conditions should prevail into Thursday morning. A sprinkle
could occur this afternoon, but no impacts are expected. Winds
may vary between southwest and southeast through the night,
gradually strengthening toward dawn. There will be a strong low
level jet moving overhead at this time, so there could be some
marginal LLWS depending on how much the surface layer decouples.
Only included this mention at CHO and MRB for now.

Southwest gradient winds quickly increase Thursday morning, and
could gust in excess of 30 knots at times. There remains some
uncertainty in convective coverage and timing for Thursday,
which could depend on upstream convection today. Latest guidance
suggest a mid afternoon peak in probabilities. PROB30 groups
have been used due to the combination of low coverage and low
confidence. MRB may largely miss out on the potential for
stronger storms, but the strongest could produce severe gusts
elsewhere. A second round of showers could affect portions of
the area Thursday night into Friday morning, but impacts are
uncertain. Skies should gradually clear Friday with gusty
northwest winds.

Gusty NW winds around 20-25 kts can be expected Saturday, but will
lighten up and turn out of the south into Sunday at around 12 to 18
kts. VFR conditions are expected throughout this time.

&&

.MARINE...
Southwest to southeast winds are expected through tonight and
will gradually increase, supporting Small Craft Advisories for
portions of the waters by late this afternoon and most waters
tonight. High end advisory conditions are likely Thursday as
strong low pressure passes to the north. Issued a Gale Watch for
the upper tidal Potomac River and portions of the northern
Chesapeake as multiple models show 35 kt winds in the mixed
layer. However, realization of these conditions (and thus the
need to upgrade to a warning) will depend on: (1) mixing quickly
during the morning hours while the low level jet is overhead,
which might be thwarted by clouds and showers, and (2) the
pressure gradient being strong enough when winds shift westerly
in the afternoon for a second peak in gusts. By afternoon, the
strongest gusts will be near the shore as air temperatures rise
into the 90s. Special Marine Warnings may be needed during the
afternoon and early evening as scattered strong to severe
thunderstorms potentially track over the waters.

There may be a bit of a break in the winds Thursday night as the
front slows down. Marginal Small Craft Advisories may be needed
for portions of the waters Friday in northwest flow.

Winds on Saturday will be out of the NW and near SCA criteria in the
wake of a secondary cold front. Winds will likely taper off
into Saturday evening as they gradually turn out of the south.
We then get into a favorable southerly channeling pattern, which
could necessitate SCAs once again Saturday night into Sunday.

&&

.TIDES/COASTAL FLOODING...
As an increasing southwesterly flow evolves ahead of a cold
front, anomalies will peak tonight into Thursday morning.
Several locations may experience minor tidal flooding late
tonight into Thursday morning. Advisories have been issued for
Annapolis and Havre de Grace, where confidence is currently
highest. Annapolis may even approach moderate flood stage.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from midnight tonight to 9 AM EDT
     Thursday for MDZ008.
     Gale Watch from Thursday morning through Thursday evening for
     MDZ008.
     Coastal Flood Advisory from 5 AM to 1 PM EDT Thursday for
     MDZ014.
     Coastal Flood Advisory from 10 AM to 4 PM EDT Thursday for
     MDZ508.
     Wind Advisory from 7 AM to 6 PM EDT Thursday for MDZ509-510.
VA...None.
WV...Wind Advisory from 7 AM to 6 PM EDT Thursday for WVZ501.
MARINE...Small Craft Advisory from midnight tonight to 9 AM EDT
     Thursday for ANZ530-535.
     Gale Watch from Thursday morning through Thursday evening for
     ANZ530-531-535-538.
     Small Craft Advisory until 9 AM EDT Thursday for ANZ531-538.
     Small Craft Advisory until 8 PM EDT Thursday for ANZ532>534-
     539>543.
     Small Craft Advisory from midnight tonight to 8 PM EDT
     Thursday for ANZ536-537.

&&

$$

DISCUSSION...ADS/CJL
AVIATION...ADS/CJL
MARINE...ADS/CJL