McLean, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

239
FXUS61 KLWX 260715
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
315 AM EDT Tue May 26 2026

.WHAT HAS CHANGED...
Continue to monitor developing fog across the area that could
require a Dense Fog Advisory. For this afternoon, models
indicate some flood threat will be present due to slow storm
motion and heavy rainfall.

&&

.KEY MESSAGES...
- 1) Localized flood threat today, with flood and severe
  thunderstorm threats areawide Wednesday.

- 2) High pressure moves into the region Friday, with
  temperatures remaining seasonable into next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Localized flood threat today, with flood and severe
thunderstorm threats areawide Wednesday.

Weak surface high to the north will push offshore while a stalled
frontal boundary lingers over the region through Wednesday. Areas of
mist and fog this morning slowly dissipate after sunrise, with
spotty showers possible through the early afternoon.

The Bermuda High remains in place across the southwestern Atlantic,
with split flow across the central CONUS converging over the Mid-
Atlantic. Deep southerly flow on the western periphery of the
Bermuda High continues to advect deep tropical moisture into our
area. Expecting another round of diurnally driven showers and
thunderstorms today. Light southeast flow develops today, which will
favor showers and thunderstorms west of the Blue Ridge and in
Central VA.

Storm motion is going to be slow and erratic due to weak low-level
flow. Very high PWATs around 1.9" and a deep warm cloud layer could
yield rainfall rates in excess of 1-2"/hr in the strongest storms.
This could result in a flood threat, especially if thunderstorms
become locked to the terrain (which could yield are higher flood
threat for that local area). The RRFS and HRRR indicate this is a
possibility. WPC has a Marginal Risk (level 1 of 4) for flash
flooding in these areas, and that aligns well with the current
thinking of how many heavy thunderstorms will develop. One of the
underlying uncertainties is going to be where these storms develop.
Overall, the flood threat is on the low side, but potential impacts
could be higher.

By Wednesday the upper troughing to the north begins to slide south,
with an accompanying cold front also pushing south through the Mid-
Atlantic. The presence of growing instability, lingering deep layer
moisture, and much more forcing/shear from the upper trough is going
to introduce a severe weather threat for most of the area. Coverage
of thunderstorms is still uncertain, but it will certainly be more
than Tuesday. Storm motion is going to be faster as deep-layer winds
increase, but locally heavy rainfall could produce some flood
threat, especially in urban areas. SPC has introduced a Marginal
Risk (level 1 of 5) for sever thunderstorms on Wednesday.

Dry conditions and sunshine finally return Thursday.

KEY MESSAGE 2...High pressure moves into the region Friday,
with temperatures remaining seasonable into next week.

Skies trend clearer beginning Thursday and going into Friday as
surface high pressure transitions into the region, along with
significant dry air coming in from the north. Despite an upper-level
low swinging down into the Northeast that could bring a very slight
chance for showers to form here along the southern edge of the
region, persistent high pressure off to the west will quickly
transition the low offshore and minimize precipitation chances in
the area. This pattern signal has stayed consistent over several
model runs now, but it`s still worth noting that any southward shift
in track from this low would increase any chance for showers over
the weekend. For now, it looks like only a slight uptick in cloud
cover will result from this while the stemming cold front keeps
temperatures moderate through the end of the forecast period. Highs
consistently range in the 70s for most areas through Monday, with
lows generally ranging in the 50s overnight between Friday and
Monday. Conditions remain clear going into next week on Monday, with
upper-level ridging persisting.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Areas of fog and low clouds will produce LIFR conditions at some
terminals. The stalled boundary over the area will continue sub-MVFR
conditions into this afternoon, but improvements to VFR are likely
for several hours. CIGs drop again tonight to IFR to LIFR levels.
Restrictions persist into Wednesday. Afternoon to evening
thunderstorms are likely to move across the area, and this could
lead to brief reductions and gusty winds at all terminals. A cold
front sweeps through Wednesday night, with dry and VFR conditions
returning for Thursday.

VFR conditions are expected Friday and Saturday. Light northwest
winds could temporarily flow west between Friday and Saturday before
returning to northwest flow.

&&

.MARINE...
Light southeast winds develop this afternoon, then become variable
tonight into Wednesday. Areas of dense fog are possible this
morning. Thunderstorms are possible across the waters Wednesday
afternoon, and Special Marine Warnings may be needed. Small Craft
Advisory conditions are possible Thursday into Thursday night.

Wind gusts predominantly stay below SCA criteria on Friday, but
could briefly approach low-end SCA criteria in the southern portions
of the Chesapeake Bay in the morning. Winds start to increase over
the waters late Saturday afternoon and evening, with SCAs becoming a
possibility over the southern Bay during then. Northerly winds
briefly trend southerly on Friday night before flowing northerly
again by Saturday evening.

&&

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

&&

$$

DISCUSSION...KRR/SRT
AVIATION...KRR/SRT
MARINE...KRR/SRT