542
FXUS61 KLWX 020054
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
854 PM EDT Sat Aug 1 2026

.WHAT HAS CHANGED...
Updated short term POPs. Otherwise, previous forecast remain on
track. The signal for heavy rainfall has continued to increase
west of the Blue Ridge for Sunday. This will need to be closely
monitored if the need for Flood Watches arises.

&&

.KEY MESSAGES...
- 1) Locally heavy rain possible Sunday into Monday, with an
  active weather pattern expected much of next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Locally heavy rain possible Sunday into Monday,
with an active weather pattern expected much of next week.

The main system of interest is an expansive upper low spinning
across Indiana. This broad cyclonic circulation is forecast to
push eastward over the next few days which will lend itself
toward an increasingly active convective pattern into next week.

The initial surface pattern has not changed a whole lot in the
past 24 hours. A frontal zone remains stalled near Savannah,
Georgia while evolving into a warm front across the Mid-South.
This frontal system extends into an occluded low which
accompanies the vertically stacked upper low over Illinois. High
pressure over the Mid-Atlantic region has largely filled,
although gradients still remain weak. Winds have shifted over to
south to southeasterly which has aided in an uptick in dew
points/humidity levels.

For tonight, showers increase in coverage for the Blue Ridge
westward. Forecast lows fall into the 60s to low 70s (mid 70s
for the metro hubs).

By Sunday, the influence of the upstream closed low begins to
enter the picture as it pushes along the Ohio River. While
evolving into more of an open wave, this eventual positively-
tilted trough will begin to lower heights across areas west of
I-95. As these modest height falls move in during peak heating,
these locations would offer the most likely opportunity for
strong to severe thunderstorms. The increasingly moist
environment will favor abundant low clouds which would curb
instability levels. Any cloud breaks would offer the best
opportunity for destabilization. Although downdraft CAPE levels
are unimpressive, the fact precipitable water values rise to 2
to 2.50 inches will favor water-loaded downdrafts capable of
strong and gusty winds. With this tropical air mass entering the
picture, cannot fully rule out the threat for flash flooding
despite the ongoing drought. A number of 12Z high-resolution
models show north/south oriented patches of 3 to 5 inches,
albeit in different spots from one another. With abundant clouds
and showers in the area, highs will drop down into the upper
70s to mid 80s.

Models agree on a bit more eastward acceleration of the upper
trough on Monday. A meridional (north/south) oriented frontal
zone sits off to the west as abundant modified tropical moisture
streams poleward. This generally focuses the upper-echilon
moisture content to east of the Blue Ridge. Models still favor
precipitable water values on the order of the 95th to 99th
percentile based on early August climatology. Numerical guidance
is all over the place in terms of precipitation placement.
However, the environment certainly supports torrential
downpours. Any flash flood threat will be dependent on: (1)
Which areas see heavy rainfall the day before, (2) If repeat
convection occurs, and (3) Whether vulnerable urbanized/poor
drainage locations are impacted. For now, will continue to
monitor the situation. Expect highs to push back into the mid
80s, with some overnight fog possible where heavier rain falls.

Shower and thunderstorm chances continue each afternoon and evening
as we sit within the warm sector. Meanwhile, waves of low pressure
will continue to pivot through as a stalled boundary sits just south
and east of the area. Ample moisture will yield efficient rain
producing storms and oppressive humidity values for the middle and
end of next week. This is due largely in part to no significant
front to flip over the airmass.

The greatest concentration of storms each day will likely be over
the terrain and in/around where the bay/river breeze sets up.
Overall coverage will remain scattered, but likely amplified during
the peak heating period given the high PWATS (1.5-2"+) sitting over
the region. Any flood threat would remain relegated to poor drainage
areas pending repetitive rounds of storms or if storm track/sit over
an urban location. Highs get back close to 90 degrees Tuesday
through Saturday next week. Overnight lows will fall back into
the mid to upper 60s.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Prevailing VFR tonight outside any showers.

For Sunday, ceilings should lower through the day as enhanced
moisture streams northward ahead of an upper low. Light to
moderate rain showers move in from west to east which would
eventually impact all terminals. With thunder being more
questionable due to low clouds, will keep a PROB30 group during
the afternoon to early evening. Sub-VFR conditions persist into
the night which may be accompanied by low clouds and fog.
Although some breaks are expected at times, the upper low will
drive further showers and more restrictions for Monday, possibly
into Monday night as well.

Expect sub-VFR conditions (brief MVFR to IFR conditions) to continue
at times Tuesday through the upcoming weekend as the front stalls
nearby. North to northeast winds Tuesday switching to the
south/southeast Tuesday night into Thursday.

&&

.MARINE...
Southerly gusts up to 20 to 25 knots are expected
through the evening and portions of the overnight period. South
to southeasterlies remain elevated for much of Sunday into early
Monday. Additional advisories will likely be needed. Further,
increasing convective chances may necessitate a few Special
Marine Warnings, particularly on Sunday.

Overall no marine hazards are expected Tuesday through Wednesday
morning. SCA southerly channeling is possible over portions of
the waters during the afternoon and evening hours Wednesday
through Friday.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies slowly rise this weekend as southerly flow
strengthens, with sensitive locations approaching minor flood stage
at times over the next few days. Annapolis is most likely to see
minor tidal flooding. South winds are forecast to persist for much
of next week, so additional periods of coastal flooding are possible.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 4 AM EDT Sunday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 4 AM EDT Sunday for ANZ530>534-
     537>543.
     Small Craft Advisory until 11 PM EDT this evening for ANZ535-
     536.

&&

$$

DISCUSSION...BRO/CPB/EST
AVIATION...BRO/CPB/EST
MARINE...BRO/CPB/EST

NWS LWX Office Area Forecast Discussion