319
FXUS61 KLWX 230133
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
933 PM EDT Sun Sep 22 2024

.SYNOPSIS...
A frontal system will stall over the area into Monday. A strong
front and area of low pressure over the Great Lakes and Upper
Midwest will approach the area during the early to middle part
of the week. High pressure will follow mid to late week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
EVENING UPDATE...
Low clouds have built in over much of the area after sunset,
especially west of I-95. These are expected to continue into
tomorrow, and some fog/lowering ceilings could develop again
tonight. High clouds also build in from the west for a few hours
tonight as a weak shortwave approaches, which could reduce some
of the low cloud cover along and west of I-85 before redeveloping.

PREVIOUS DISCUSSION FOLLOWS...
Latest satellite imagery shows abundant cloud cover across the
region thanks to easterly flow and a backdoor cold front draped
across the region. A few showers or areas of drizzle are
possible along the backdoor front into the evening, but with
diminishing forcing aloft expect coverage to be isolated to
widely scattered. Some improvement in clouds diminishing is
expected west of the Blue Ridge, with areas to the east in large
remaining socked in the clouds with the easterly flow.

Low temperatures tonight will drop into the upper 50s to mid
60s. A few showers, drizzle, or fog are still possible
generally west of US-15 in the vicinity of the stalled front
tonight.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
The forecast remains on track for Monday with little changes
expected. Thus, expect lingering cloud cover for much of the
area along with muted diurnal temperature spread.

As another trough and area of low pressure/frontal system begin
to approach from the OH Valley/Great Lakes by Monday afternoon,
expect increasing rain chances from west to east. Greatest
potential for rain likely arrives overnight Monday. Generally
light QPF with this system with an overall quarter inch expected
for most. This system will gradually push across the area
Tuesday and Tuesday night with showers and a few thunderstorms
likely.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A wavy frontal system will slowly move or stall across the area Wed-
Thu bringing more showers and thunderstorms. It`s uncertain how far
south this front can get given blocking ridge along the East Coast.
There could also be some flood concerns given slow movement of this
frontal system.

At the end of the week, remnants of a tropical cyclone are expected
to be pulled northward into the southern Mid-Atlantic and eventually
get absorbed into a large upper low over the mid MS River valley.
Lots of uncertainty at the end of next week, but not looking as wet
as earlier in the week.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Primarily MVFR CIGS this afternoon which may gradually
scattering out by this afternoon, perhaps a bit earlier at MTN
as a backdoor front pushes through. Winds will be E/NE 5-10 kts
through tonight. MVFR gradually builds back in tonight and CHO
and MRB could see IFR.

Onshore flow continues Monday into Tuesday with bouts of lower
CIGs and patchy fog (especially overnight) possible at times.
Showers and a few thunderstorms are possible late Monday
afternoon through Tuesday night. Favoring more showers than
thunderstorms at this juncture.

Expect numerous to widespread showers Wed-Thu with a slow moving
front. Flight restrictions seem likely at some point.

&&

.MARINE...
Onshore flow is expected through Tuesday night. A few gusts of
15-20 kts are possible at times in the wake of a backdoor front,
though most of the time should be sub-SCA.

SCA conditions are possible Wednesday on SE winds.

&&

.TIDES/COASTAL FLOODING...
A very prolonged period of onshore flow (east to southeast)
will continue through much of the week. Minor coastal flooding
is likely at high tide at all sensitive locations for the next
few days. Coastal Flood Advisories are in effect for nearly the
entire western shoreline of the Chesapeake Bay and tidal Potomac
River, including Washington DC. A steady rise in anomalies is
expected to produce Moderate flooding at Annapolis and Washington
DC SW Waterfront/Alexandria through tonight. As a result, a
Coastal Flood Warning remains in effect. Expect headlines to be
extended for much of the upcoming week.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Warning until 5 AM EDT Tuesday for DCZ001.
MD...Coastal Flood Warning until 5 AM EDT Tuesday for MDZ014.
     Coastal Flood Advisory until 5 AM EDT Tuesday for MDZ011-
     016>018-508.
VA...Coastal Flood Warning until 5 AM EDT Tuesday for VAZ054.
     Coastal Flood Advisory until 5 AM EDT Tuesday for VAZ057.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...DHOF/CPB
NEAR TERM...CPB/CAS
SHORT TERM...CPB
LONG TERM...LFR
AVIATION...LFR/CPB/CAS
MARINE...LFR/CPB
TIDES/COASTAL FLOODING...LWX