659
FXUS61 KLWX 151756
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
156 PM EDT Sun Sep 15 2024

.SYNOPSIS...
High pressure to the northeast will continue to impact the area
through Monday. An area of low pressure off the southeastern
U.S. coast is expected to move northwestward or northward toward
the Carolinas early this week, potentially bringing heavy rain
and coastal flooding Tuesday into Wednesday. Additional rainfall
is possible throughout the work week.

&&

.NEAR TERM /THROUGH TONIGHT/...
High clouds will continue to move through this afternoon after
the earlier low clouds eroded across the I-95 corridor. Mostly
sunny conditions will continue through the afternoon and early
evening hours. Highs will top out in the upper 70s to low 80s.
Winds will be elevated throughout the afternoon with gusts up to
20 mph possible before diminishing later this evening.

By tonight, high clouds will continue to move further north and
become more dense in nature, especially across central VA. Low
clouds will develop again across the eastern areas late tonight
into Monday morning. Overnight lows will fall into the mid 50s
to low 60s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
High pressure to the north will continue to influence the area
locally through Monday evening, leading to mostly dry
conditions. Moisture availability may be amplified across
central VA, allowing for an isolated shower later in the day on
Monday. Highs will top out in the mid to upper 70s to near 80
for most of the lower elevations. Upper 60s will be more common
across the mountains.

Low pressure off the southeast coast is expected to begin moving
inland late Monday night into Tuesday morning. Expect initially
stratiform light rain/drizzle by Tuesday morning as low-levels
saturate and surface wedge erodes.

Forecast for Tuesday into Wednesday still largely depends on
eventual track of coastal low with NHC`s specialized regional
and consensus models indicating a track more across South
Carolina and the southern Appalachians. Scenarios range from
basically getting no rain to seeing multiple inches of rain
during the Tuesday-Tuesday night time frame. At this time, some
rain still appears likely Tuesday-Tuesday night time frame, but
how much rain falls and how impactful it would be is still to
be determined. For now, the expectation for QPF through Tuesday
night is widespread 1-2" with locally up to 6", with the higher
amounts possible across the eastward facing slopes of the Blue
Ridge. A lot may change within the forecast as the forecast
track becomes more apparent. Continue to monitor our forecast
locally as well as the National Hurricane Center.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Uncertainty in the forecast persists into the middle to latter
portions of the week. The area of low pressure from earlier in the
week is likely to be somewhere in the vicinity of the Mid-Atlantic
region on Wednesday. However, there is general model agreement that
the system should be in the process of weakening. Looking aloft, a
broad mid/upper low lingers over the Mid-Atlantic down into the
southeastern U.S. through at least Friday. Persistent cyclonic flow
maintains daily shower chances, which may be accompanied by a threat
for diurnally-driven thunderstorm activity. Heading into the
weekend, upper ridging starts to settle over the Great Lakes and New
England which pushes the cyclonic circulation further to the
south. As a result, expect a gradual shift to drier conditions
for the weekend. Surface high pressure settles into the eastern
U.S. which helps lower humidity levels.

Near average temperatures are expected through Friday before turning
a bit cooler over the weekend. By Saturday and Sunday, forecast high
temperatures fall into the low/mid 70s, with 60s over the mountains.
There is sizeable ensemble spread but the downward trend in
temperatures is pretty clear in the guidance.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR conditions will likely continue through the remainder of the
day. IFR ceilings develop by 12Z Monday improving to MVFR/VFR
Monday afternoon. Rain moves in Tuesday with IFR ceiling
restrictions likely. Rain likely continues through Tuesday
night before diminishing Wednesday.

With the residual low pressure nearby, expect periods of sub-VFR
conditions, particularly on Wednesday into Thursday. Initial
easterly winds will eventually give way to north-northeasterlies.
This is accompanied by afternoon winds which may gust up to 15
knots.

&&

.MARINE...
SCA conditions will remain possible through Monday morning,
mainly across the southernmost waters, then become increasingly
likely Monday night into Tuesday morning as gradient tightens in
response to approaching coastal low and high pressure to the
north. At this time, the risk of gale force winds appears low.

As a weakening area of low pressure tracks through the area, winds
will be out of the east on Wednesday before shifting to
northeasterly on Thursday. While Small Craft Advisory caliber winds
are not shown, some locations could stay close to 20 knots during
the period.

&&

.TIDES/COASTAL FLOODING...
Light but persistent onshore flow will cause water levels to
gradually rise over the next couple of days. Onshore flow
strengthens further Monday afternoon into Tuesday morning with
minor coastal flooding becoming increasingly likely by Tuesday
morning. 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. However, at this time, all of the surge
guidance available only indicate minor flooding occurring.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory from 5 AM Monday to 10 PM EDT Tuesday
     for DCZ001.
MD...Small Craft Advisory from 6 AM to 6 PM EDT Monday for MDZ008.
     Coastal Flood Advisory from 2 AM Monday to 10 PM EDT Tuesday
     for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Monday for
     ANZ530>532-536-538>542.
     Small Craft Advisory until midnight EDT tonight for ANZ531-532-
     539>542.
     Small Craft Advisory until 6 PM EDT Monday for ANZ533-534-537-
     543.

&&

$$

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