378
FXUS61 KLWX 142332
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
732 PM EDT Sat Sep 14 2024

.SYNOPSIS...
High pressure to the north will continue to impact the area
locally through the weekend and into early next week. An area
of low pressure is expected to form off the southeast U.S. Coast
this weekend before moving northwestward toward the coast
during the first half of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Mostly dry conditions will continue tonight with lows in the
50s for most areas with low 60s possible near the waters. Cannot
rule out an isolated sprinkle or patchy drizzle across central
VA/southern MD as clouds move more into those areas heading into
Sunday morning.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
High pressure to the north will continue to build further south
Sunday into early next week, leading to dry conditions locally.
Overcast skies will build across central VA and southern MD as
an area of low pressure forms off the NC coastline.

By Monday night, high pressure shifts offshore, while at the
same time, coastal low pressure begins to move inland increasing
the onshore flow, bringing abundant cloud cover, initially high
level clouds, then lowering toward daybreak Tuesday. However,
any precipitation is likely to hold off until after daybreak
Tuesday.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
The key feature of interest next week is related to a region of
either subtropical or tropical development off the Carolina coast.
What remains of the surface and upper air circulation is expected to
slowly lift northward in time. Ensemble surface low plots indicate
there is still quite a bit of spread among the global ensemble
members. Some solutions carry the system toward the Appalachians
while others move east of the Delmarva Peninsula. Depending on the
track, quality of tropical moisture, and speed of the system, some
heavy rainfall signal may emerge. Given the current area of
interest is just a blob of disorganized convection near the Gulf
Stream offshore of the Carolinas, uncertainty is quite high at
this point. For now, expect a multi-day period of increasing
rain chances which may run through the remainder of the work
week.

A blocky pattern persists across North America with a rex block
potentially setting up into next weekend. A meandering negative
height anomaly persists over the eastern U.S. while heights build to
its north. Where this ridge/trough couplet sets up will dictate the
degree of additional shower chances. As expected, uncertainty is
high through much of the period next week.

Overall temperatures stay near to slightly below average next week.
Clouds should be plentiful given the slug of tropical moisture
surging northward into the Mid-Atlantic region. As a result, this
will raise humidity levels for much of the week.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
The last few runs of the HRRR and GLAMP both have IFR/LIFR CIGs
at CHO/IAD 8Z-13Z Sunday. Will monitor. Other guidance tries to
bring in lower CIGs from the E/SE to DCA/BWI/MTN. MRB may be
susceptible to patchy fog early Sunday morning.

Otherwise, periods of MVFR/IFR CIGs are possible through 12Z
Monday, mainly at KCHO; elsewhere, mostly VFR conditions will
persist. Strengthening onshore flow late Monday night is likely
to result in more widespread CIG restrictions by 12Z Tuesday.

Enhanced onshore flow combined with increasing rain showers will
make for a lengthy period of restrictions from Tuesday through
Thursday. While some breaks are likely at times, expect sub-VFR
ceilings to dominate. Depending on the degree of instability, there
could be a few thunderstorms on Tuesday into Wednesday as the
coastal low tracks nearby. Otherwise, a breezy east to northeasterly
wind is expected to dominate.

&&

.MARINE...
SCA winds are likely later this evening, especially south of
North Beach MD. Winds gradually strengthen Sunday into Monday
with SCA conditions becoming increasingly likely. The strongest
winds are most likely late Monday into Tuesday.

The gradient formed by high pressure to the north and low pressure
approaching from the southeastern U.S. will lead to a breezy east to
northeasterly wind. Current forecast gusts on Tuesday into Wednesday
range from 20 to 25 knots, possibly increasing to around 30 knots
over the southern waters. There is an outside chance for gale force
wind gusts, but confidence is low given uncertainties in the low
track and strength.

&&

.TIDES/COASTAL FLOODING...
Light but persistent onshore flow will cause water levels to
gradually rise over the next several days. Onshore flow
strengthens further Monday night into Tuesday with minor coastal
flooding becoming increasingly likely by Tuesday. Depending on
the strength of onshore flow and the track of low pressure to
the south/southwest, near moderate flooding may be possible at
vulnerable shoreline locations late Monday through Tuesday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from noon Sunday to midnight EDT Sunday
     night for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from noon Sunday to midnight EDT Sunday
     night for ANZ530>532-535-536-538>542.
     Small Craft Advisory until 6 AM EDT Monday for ANZ533-534-537-
     543.

&&

$$

SYNOPSIS...DHOF/ADM
NEAR TERM...DHOF/ADM
SHORT TERM...DHOF/ADM
LONG TERM...BRO
AVIATION...BRO/DHOF/ADM
MARINE...BRO/DHOF/ADM
TIDES/COASTAL FLOODING...LWX