Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 240102
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
902 PM EDT Sat Mar 23 2024

.SYNOPSIS...
Gusty winds and dry conditions continue overnight as high
pressure builds in over the region and a cold front departs to
our southeast. Dry conditions continue through Monday with high
pressure overhead. Precipitation returns to the area on Tuesday
as a low pressure system impacts the area midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
Gusty winds continue tonight in the wake of a cold front
departing to our southeast. High pressure builds over the region
tonight leading to dry conditions areawide. Low temperatures
tonight will be noticeably cooler compared to last night, with
temperatures in the 20s and low to mid 30s. Have maintained the
Wind Advisory for the Blue Ridge zones due to the strong signal
for 40-45 kts this evening into tonight. Cloud cover will
decrease as dry air filters into the region.

&&

.SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Dry high pressure returns Sunday with gusty northerly flow
continuing. Gusts of 20 to 30 mph can be expected with high
temperatures in the upper 40s and mid 50s under mostly sunny
skies. Lows Sunday night will fall into the upper 20s and low to
mid 30s as winds slowly diminish.

1040 mb high pressure over eastern Canada will wedge its way
south along the Appalachian Mountains before shifting offshore
through the start of the upcoming workweek. This will lead to
decreasing winds, dry conditions, and near normal temperatures
Monday. Highs will push into the mid to upper 50s and low 60s
with overnight lows in the 30s and 40s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
The longwave pattern features a slow moving upper trough which
approaches the Eastern Seaboard by mid-week. As most models have
continued to show, the core of the forcing and associated
dynamics lift northward across the Great Lakes into Ontario.
Heights falls are fairly weak over the local area which will
bring a loosely defined cold front through the I-95 corridor by
late Wednesday. In advance of this system, clouds should
increase in coverage on Tuesday into Wednesday. This is
accompanied by some light shower activity with total forecast
rainfall amounts between 0.10-0.25 inches.

An active southern stream continues to depict a more amplified
wave tracking toward the southeastern U.S. on Thursday. Dynamics
associated with this system combined with colder air overriding
the Gulf Stream will induce a wave of low pressure off the
Carolina coast. Depending on the track, some rainfall may return
to the Mid-Atlantic region late in the work week. This has been
maintained in the forecast package through Friday morning.
Global ensembles agree on the existence of this surface low, but
vary with placement and strength. Until this gets further
ironed out, the predictability of local impacts remains on the
low side. Behind this system, expect a greater deal of sunshine
on Friday into next weekend as high pressure approaches from the
west. Northwesterly winds may become gusty depending on how
tight the gradient is between the coastal low and high pressure
off to the west.

Regarding temperatures, expect fairly seasonable conditions
through Friday before a potential warmup ensues next weekend.
While ensemble spread increases in time, the general trend in
the guidance is for milder weather into the more extended
periods.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Conditions will improve to MVFR and VFR quickly this afternoon.
NNW to N winds will strengthen this afternoon and peak around
06Z Sun with gusts 30-35 kt. Winds begin to diminish Sun but
still gusty around 20 kt.

VFR conditions are expected Sunday through Tuesday as strong high
pressure builds into the region. The departing front and low
pressure system offshore combined with the building high pressure
will lead to the continuation of gusty northerly winds through
Sunday evening. Gusts of 15 to 25 kts can be expected with the
highest gusts likely at terminals east of the Blue Ridge and in
particularly along the corridor Sunday afternoon. Winds will subside
(5-10 kts) and turn toward more of a east/southeast direction as
high pressure strengthens over the area Monday into Tuesday.

Southeasterly winds persist into early Wednesday before turning
more southerly through the day. In advance of a cold front,
expect thickening clouds and some possible restrictions. Rain
showers are in the forecast through mid-week as this boundary
pushes through late Wednesday. Winds turn northwesterly in the
wake with additional rainfall chances possible as a coastal
system develops near the Carolinas late Thursday. Gusts up to 20
knots are possible as well with the potential for sub-VFR
conditions depending on how far north the rain threat takes
place.

&&

.MARINE...
Gale Warnings have been moved up in time across all waters and
remain in effect through Sunday morning as low pressure passes
by. Gusts of 35 to 40 kts are expected especially later evening
and into the first half of Sunday as the gradient tightens.

SCA level winds are expected late Sunday into early Monday morning
as high pressure builds back over the region. Sub-SCA level winds
out of the east and southeast return Monday into Tuesday with
wedging high pressure overhead. SCA level winds return with a weak
front and coastal low pressure by the middle to end of next
week.

&&

.FIRE WEATHER...
A beneficial soaking rain occurred this morning which should
help containment efforts with ongoing wildfires over the
Shenandoah Valley and eastern WV. With the added rain, smoke
left over at the surface should scatter out leading to improved
air quality within the aforementioned region.

Winds increasing out of the south and southeast at 10
to 20 sustained this afternoon and evening. Gusts of 25 to 35 mph
are expected during this time as the gradient tightens between low
pressure passing to the south/east and incoming high pressure from
the eastern Canada/Great Lakes region. Maximum RH values of 85 to
100 percent are expected this morning before falling into the 60 to
70 percent range this afternoon.

Dry and breezy conditions look to continue Sunday although winds
will slowly diminish. North/northeasterly winds look to gusts 20 to
30 mph with minimum RH values falling back into the 25 to 35
percent range. Portions of the central and southern Shenandoah
Valley and eastern slopes of the Alleghenies could see minimum RH
Values as low as 20 to 25 percent Sunday afternoon. This is due to
the gradient wind and added sunshine as high pressure builds
overhead.

Winds continue to decrease Monday before returning Tuesday as a weak
front approaches the region. Minimum RH values Monday will remain
between 25 to 30 percent before increasing into the 40 to 45 percent
Tuesday.

&&

.TIDES/COASTAL FLOODING...
In the wake of low pressure, strengthening northerly flow will
cause a decline in water levels Saturday night through Sunday.
Low water level issues may arise during the second half of the
weekend, especially over northern portions of the Chesapeake
Bay.

A prolonged period of tidal flooding is possible starting Monday
into midweek amidst southerly flow. Minor flooding is most
likely at the sensitive locations, with moderate flooding not
out of the realm of possibilities.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...Wind Advisory until 2 AM EDT Sunday for VAZ507-508.
WV...None.
MARINE...Gale Warning until noon EDT Sunday for ANZ530>534-537-539>543.
     Gale Warning until 6 AM EDT Sunday for ANZ535-536-538.

&&

$$

SYNOPSIS...AVS
NEAR TERM...AVS/CPB
SHORT TERM...CPB
LONG TERM...BRO
AVIATION...BRO/CPB/EST
MARINE...BRO/CPB/EST
FIRE WEATHER...CPB/EST
TIDES/COASTAL FLOODING...CPB


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