578
FXUS61 KLWX 120110
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
910 PM EDT Sat Jul 11 2026

.WHAT HAS CHANGED...
Showers and an isolated thunderstorm continue to move through
the forecast area. The threat for flash flooding and damaging
wind gusts continues as an outflow boundary drops through the
region, with showers and thunderstorms popping up along it. Will
continue to monitor.


&&

.KEY MESSAGES...
- Heavy showers and strong thunderstorms, a few of which may
  produce damaging winds and flash flooding, are possible this
  afternoon and evening.

- Heat and humidity return for the middle and second half of
  next week.

- Scattered thunderstorm development is anticipated during the
  the second half of next week in a moderately unstable and
  sheared environment.

&&

.DISCUSSION...
KEY MESSAGE 1...Heavy showers and strong thunderstorms, a few of
which may produce damaging winds and flash flooding, are possible
this afternoon and evening.

As of 3 PM, radar imagery shows several areas of showers and
thunderstorms scattered about the area. Showers that have
developed in the vicinity of the bay breeze have struggled to
mature. They have yet to produce lightning, and aren`t showing
signs of intensification at the moment.

Additional showers and storms are present along and west of the
Blue Ridge. These storms have formed downstream of an MCV
approaching from the Ohio Valley. These storms should continue
to slowly drift off toward the south and east through the
remainder of the afternoon and evening.

Finally, a third area we continue to monitor is up to our north
in PA/NJ. A cold front has sparked the development of showers
and storms from southern NJ northwestward into central PA.
These storms will drop southward into our forecast area during
the evening hours. With an unstable airmass in place, these
storms may persist well after dark from the DC Metro southward
to southern MD, until the front finally clears the area later
tonight.

Forecast soundings show an environment with saturated profiles
through the vertical, around 1000 J/kg of MLCAPE, 400-600 J/kg
of DCAPE, and around 20-30 knots of mid-level flow. While this
environment isn`t overly favorable for strong downbursts, an
instance or two of damaging winds can`t be completely ruled out.
SPC has much of the forecast area outlooked in a Marginal Risk
(level 1 of 5) for severe thunderstorms.

With the saturated profiles, deep warm cloud layers (around 14k
ft), and precipitable water values approaching 2 inches, storms
today should be very efficient heavy rainfall producers.
However, ample flow in the mid to upper levels should enable
storms to be somewhat progressive. The weak low-level jet and
lack of focused areas of stronger low-level convergence should
also limit backbuilding to a degree. However, it`s possible that
there could be an isolated instance or two of flash flooding if
localized storm mergers are able to prolong the period of
heavier rain. The best chance for this to occur may be later
this evening along the I-95 corridor from DC southward, where
there could be some potential for outflows moving in from the
west to collide with the front and associated storms moving in
from the northeast. At this time, the threat for flooding
appears to be low (not rising to a threat level worthy of a
Watch), but non- zero. We`ll continue to monitor trends over the
course of the day. WPC currently has much of the area outlooked
in a Marginal Risk (level 1 of 4) for excessive rainfall.

As the front weakens and progresses southward, it will struggle
to scour out low- level moisture. As a result, we`ll have
another threat for showers and thunderstorms tomorrow afternoon,
primarily to the southwest of the Potomac. The background
environment doesn`t appear to be overly favorable for severe
thunderstorms or flash flooding, but an isolated instance of
flash flooding can`t be ruled out across Central Virginia or the
Central Shenandoah Valley. WPC has those areas outlooked in a
Marginal Risk (level 1 of 4) for excessive rainfall on Sunday.

KEY MESSAGE 2...Heat and humidity return for the middle and second
half of next week.

Upper high centered over the Dakotas early in the week is expected
to expand eastward cresting over the area Tue evening. This will
support high temperatures in the upper 90s, but dewpoints will not
be terribly too high in the 60s. By Thu and Fri, low level moisture
returns into the area with dewpoints in the upper 60s to near 70
resulting in heat indices near 100 degs which is still below heat
advisory criteria. While it will be hot, it won`t be as hot as it
was during the first weekend of July.

KEY MESSAGE 3...Scattered thunderstorm development is anticipated
during the the second half of next week in a moderately unstable and
sheared environment.

During the second half of next week, the upper ridge centered over
the Dakotas early in the week will build westward with time while
the eastern Canada trough digs southward. This results in moderately
strong flow aloft across the area with the synoptic pattern becoming
favorable for thunderstorm clusters or MCSs that form over the upper
Great Lks and upper Midwest to track southeastward into the OH
Valley and Mid-Atlantic states. The earliest we could see
thunderstorms it seems to be Thu, but with higher probs of
thunderstorms Fri into Sat and likely extending it beyond that.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Prevailing light winds and VFR conditions are expected through
the remainder of the day, but showers and thunderstorms are
expected across the area this afternoon into this evening.
Confidence is low on both timing and coverage of the storms, so
PROB30 groups have been maintained for now. MVFR ceilings appear
possible late tonight, with IFR even possible near CHO. MVFR
ceilings may linger through tomorrow morning, before improvement
back to VFR is seen during the afternoon. Additional
thunderstorms may be possible near CHO, but drier conditions are
expected elsewhere. Winds tomorrow will be out of the east. VFR
and dry conditions are expected on Monday, along with east to
southeasterly winds.

Fair weather is expected through mid week.

&&

.MARINE...
Sub-SCA level north to northeasterly winds are expected over the
waters today into tonight. An SMW or two can`t be ruled out as
storms move over the waters. Winds will turn out of the east
tomorrow. Small Craft Advisories have been issued for the Lower
Tidal Potomac and our southernmost Bay zones late Sunday
afternoon through much of Monday night. Lighter winds are
expected further north.

Great boating weather is expected Monday through mid week with
no thunderstorm potential. SCA conditions are likely Monday, but
winds will be diminishing by Monday evening.

&&

.TIDES/COASTAL FLOODING...
Elevated water levels will persist for the next couple of days
with minor coastal flooding becoming increasingly likely Monday
into Tuesday as southerly flow strengthens.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 5 PM Sunday to 4 AM EDT Monday for
     ANZ534-537-543.

&&

$$

DISCUSSION...AVS/LFR/KJP
AVIATION...LFR/KJP
MARINE...LFR/KJP

NWS LWX Office Area Forecast Discussion