044
FXUS61 KLWX 180113
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
913 PM EDT Sun Aug 17 2025

.SYNOPSIS...
A cold front will slide southeast across southern Maryland and
parts of eastern Virginia overnight, before stalling across our
far southern zones during the days Monday through Wednesday. The
front should push south on Thursday. High pressure will then
return from the north through Saturday.

&&

.NEAR TERM /THROUGH MONDAY/...
An elongated outflow boundary of heavy showers and embedded
strong thunderstorms extends from the central Appalachians,
across the Virginia Piedmont, into southern Maryland and
northeast up into the heart of the Delmarva Peninsula. This
activity will continue to push east and southeast as the
individual thunderstorms weaken during the next few hours. The
main cold front remains to the northwest of this boundary of
convection and should gradually push through the region from
northwest to southeast through the midnight hour. Some western
valleys will develop some patchy fog. Lows will range from the
mid 60s to mid 70s.

The front will stall out nearby Monday and probably sets up
across our southern zones. Temperatures on Monday will be
cooler than today by probably about 10 degrees. The NAM model
suggests the coolest numbers with highs near 70 to lower 70s,
while the GFS and EURO suggest numbers not as cool with highs in
the middle to upper 70s. In any sense, it is going to feel less
oppressive in terms of the heat. The humidity, on the other
hand, may still be a little on the high side. This humidity and
the front nearby could allow for a couple of rain showers or a
rumble of thunder to develop during the midday and afternoon
hours.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
The front will remain stalled Monday night through Tuesday
night. A gusty northeast wind behind the front could develop
Monday into Monday evening. Once convection wains Monday night,
some low clouds and patchy fog could evolve into early Tuesday.
Lows Monday night middle 60s to near 70.

Some drier air aloft could push into the region on Tuesday;
thus, convection may be limited to scattered and light to
moderate in intensity. Northeast winds will be lessened but
humidity may be enough overnight to allow for patchy fog to form
in valleys again Tuesday night. Lows lower to middle 60s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
By Wednesday, we`ll be situated between a shortwave trough
approaching from the northwest and Erin, which is forecast to
track well off the Carolina coast at that time, per the latest
NHC forecast. The approaching shortwave will supply some weak large
scale forcing for ascent, while compensating subsidence on the
periphery of Erin`s circulation will have the opposite effect. While
most locations should stay dry, a stray afternoon shower or storm
can`t be completely ruled out, especially across the higher terrain,
where terrain circulations may act to enhance low-level
convergence/lift. Temperatures are expected to remain below normal,
with highs in the upper 70s/low 80s for most.

The aforementioned shortwave trough is forecast to progress off to
our east on Thursday, which will push Erin further out to sea. We`ll
be left with northwesterly flow aloft and a relatively weak surface
pattern for Thursday and Friday. Light winds and near to slightly
below normal temperatures are expected during that time, with highs
in the low to mid 80s and lows in the 60s. Most locations should
stay dry, but a popup afternoon shower or storm could be possible,
especially to the west of the Blue Ridge.

High pressure will become established offshore by Saturday.
Southerly flow around the high will lead to an uptick in low-level
moisture, with dewpoints climbing back through the 60s, and
potentially even approaching 70 degrees. Meanwhile, a deep upper
trough will start to dig southeastward across the Great Lakes. Winds
aloft will start to increase locally in response to that feature. As
large scale ascent ahead of that trough starts to overspread the
area, showers and thunderstorms may be possible by Saturday
afternoon. Some of these storms could potentially be on the stronger
side, as surface based instability overlaps with increasing flow
aloft.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Thunderstorms in the CHO terminal area will bring ceilings
briefly to MVFR but winds will be a huge factor in a short
period as gusts over 40 knots will accompany the thunderstorms.
Otherwise, VFR conditions will evolve with winds shifting to
northwesterly in direction behind a passing front. Winds will
become northeast Monday and gusty with the front to the south.
Most guidance is favoring MVFR ceilings persisting all day
Monday, although CHO is more uncertain. Northeasterly winds may
also gust 15-20 kt at times through the day.

With the front stalled out just to the south, a moist airmass
will stay in place through Tuesday. MVFR ceilings likely
continue, with some IFR potential during the overnight periods.
Intermittent showers and drizzle could also reduce visibility at
times, but likely remain within the same category as ceilings
(MVFR).

Sub-VFR conditions may be possible early Wednesday morning within
onshore flow, but improvement back to VFR is expected by afternoon.
Lesser, but still non-zero chances for low clouds exist Wednesday
night. VFR conditions are expected on Thursday. Winds will generally
be out of the northeast on Wednesday and Thursday, and could gust to
around 15 to 20 knots at times.

&&

.MARINE...
Special Marine Warnings over the Chesapeake Bay will end within
another hour or so as wind gusts over 40 knots with
thunderstorms wind down through the rest of the night. Variable
winds may then prevail until a cold front arrives late tonight
into Monday morning. Northeasterly winds will increase behind
the front, with a Small Craft Advisory remaining in effect for
all waters. Winds will decrease on the inland tributaries Monday
night but likely remain elevated along the bay, so the advisory
continues there. Marginal advisory conditions may continue into
Tuesday for portions of the waters as winds turn more easterly.
Lighter east to northeast winds continue Tuesday night. Showers
and drizzle could reduce visibility at times both Monday and
Tuesday.

SCA conditions appear possible within northeasterly flow Wednesday
afternoon through Thursday as Erin passes out to sea. Gusts of
around 20 to 25 knots may be possible during that time.

&&

.TIDES/COASTAL FLOODING...
Elevated tidal anomalies persist through tonight. Annapolis is
forecast to reach minor flood again tonight during high tide.
While other locations aren`t currently forecast to flood, some
could come close (ie, Alexandria, Havre de Grace, Solomons, and
Dahlgren). A passing cold front should reduce water levels
slightly heading into Monday. However, prolonged onshore flow
will likely result in additional (possibly more widespread) tidal
flooding late Tuesday into Wednesday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 6 AM Monday to 2 AM EDT Tuesday for
     MDZ008.
     Coastal Flood Advisory from midnight tonight to 5 AM EDT
     Monday for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 6 AM Monday to 2 AM EDT Tuesday for
     ANZ530>533-539>541.
     Small Craft Advisory from noon Monday to 6 AM EDT Tuesday for
     ANZ534-537-543.
     Small Craft Advisory from 6 AM to 6 PM EDT Monday for ANZ535-
     536-538-542.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS/KLW
SHORT TERM...ADS
LONG TERM...KJP
AVIATION...KLW/KJP
MARINE...KLW/KJP
TIDES/COASTAL FLOODING...ADS