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000
FXUS61 KLWX 110800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Thu Apr 11 2024

.SYNOPSIS...
Low pressure will track into the Great Lakes today, with an
associated cold front moving through tonight. Upper troughing
will linger overhead tomorrow, with a reinforcing cold front
moving through tomorrow evening. High pressure will build to our
south this weekend. A weak area of low pressure will track to
our north late Sunday night into early Monday, before high
pressure regains control early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Current (as of 330 AM) surface analysis shows a developing area
of low pressure across northern Mississippi and western
Arkansas. Broad troughing is situated from central Canada
southward through the Mississippi Valley to the Gulf Coast. A
prominent shortwave is located within the base of the much
larger trough over the Lower Mississippi/Arkansas Valleys, while
another shortwave descends down the backside of the trough
through the Plains states. As we move forward in time, the two
shortwaves will interact, causing the broader longwave trough to
deepen and take eventually take on a negative tilt by later
tonight.

Skies are currently cloudy, but most of the area remains dry,
with just a few sprinkles and light showers scattered about the
forecast area. As we progress through the day, large scale
ascent will increase ahead of the approaching upper trough,
causing showers to break out from south the north across the
forecast area. Scattered showers will remain in place across the
forecast through much of the afternoon, with winds gradually
picking up out of the south, and temperatures making it into the
60s to near 70.

The upper trough will take on a negative tilt as moves overhead
tonight. At the surface, low pressure will deepen as it tracks
into the Ohio Valley. Thunderstorms are expected to form within
the zone of strong forcing for ascent ahead of the negatively
tilted trough this evening. Instability will increase through
the evening as a low level mass response occurs ahead of the
approaching trough. CAPE levels are expected to increase to
around 300-600 J/kg across much of the area. When coupled with
an impressive low-level jet and ample shear present, some of the
storms this evening into the overnight may be on the strong to
severe side. Damaging winds should be the primary threat, but a
brief tornado can`t be ruled out given the strong low-level jet
and 0-1 km SRH values increasing to around 200-300 m2/s2. Weak
stabilization overnight right near the surface may serve as a
limiting factor for both the damaging wind and tornado
potential. SPC currently has the area outlooked in a Marginal
Risk for Severe Thunderstorms. A few heavier downpours may also
be possible given the instability present and highly anomalous
PWAT values (near 1.5 inches). Thunderstorm activity should be
on the decrease during the second half of the night, but a few
showers may linger throughout the area.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Low pressure will continue to deepen and track northeastward
from the Great Lakes into southern Canada on Friday as upper
troughing moves in aloft. Upslope showers will continue in the
mountains, with a few showers and potentially even a
thunderstorm or two possible to the east of the mountains Friday
afternoon. The majority of the day Friday will remain dry, and
temperatures should run above normal, with highs in the 60s to
near 70 for most. Winds will remain gusty out of the southwest.

A reinforcing cold front will move through Friday evening,
with winds increasing out of the west behind the front. Gusts
may near Wind Advisory levels, particularly over the higher
terrain Friday night. Low temperatures will range from the 30s
in the mountains, to near 50 along the I-95 corridor.

Troughing will progress off to our east on Saturday, as heights
rapidly rise aloft. Winds will remain gusty out of the west-
northwest, and high temperatures are forecast to reach into the
mid-upper 60s for most.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
On Sunday, a surface low will move through the Great Lakes region
with the associated warm front draping across the forecast area.
Aloft, an upper level trough will be eroding and pivoting towards
New England. Light rain showers are possible in the afternoon,
mainly in the northern portions of the forecast area. Generally, low
end PoPs (<30%) are expected all day with a slight uptick between
8PM and 2AM as the GFS and Canadian hint at shortwave energy passing
overhead. During this time, PoPs increase to 50% in the Alleghenies
and stay between 30-40% along the MD/PA border. Elsewhere, low end
PoPs remain. In the wake of the warm front passing through, high
temperatures will be in the upper 60s to upper 70s with metro
regions possibly reaching 80. Overnight low temperatures will be in
the 50s for most.

As we head into the workweek, a stalled frontal boundary just to the
north of the area will continue low end PoPs for the northern half
of the forecast area. The frontal boundary will slowly move towards
the area, with the warm front dipping into NE Maryland by Wednesday.
This will lead to slightly increase PoPs (30-40%) Tuesday night into
early Wednesday morning. Temperatures gradually warm each day with
highs in the 70s to low 80s for most(upper 60s in the mountains).
Overnight lows will be in the 50s to low 60s.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Ceilings will gradually lower through the remainder of the
overnight into the morning hours, reaching MVFR and then
eventually IFR levels at most terminals. Showers will also
overspread the area from south to north this morning and
continue through the afternoon. Southerly winds will gradually
pick up through the day.

Thunderstorms may move in from the southwest during the first
half of the overnight. VCTS has been introduced at all terminals
during that time. A few showers may linger through the remainder
of the overnight as ceilings start to gradually improve. Winds
will turn southwesterly behind a cold front on Friday, and
ceilings will improve back to VFR. A stray shower or
thunderstorm may be possible Friday afternoon. A reinforcing
cold front will move through Friday evening, bringing another
surge in winds. Gusts of 30-40 knots may be possible at the
terminals overnight Friday night. VFR conditions and continued
gusty winds are expected on Saturday.

Gusty southwest winds are expected at all terminals on Sunday with
wind gusts of 15-20 knots expected. Overnight, winds shift to
west/northwest and diminish. Winds remain out of the west/northwest
on Monday before becoming light and variable overnight.

&&

.MARINE...
Southerly flow will gradually increase today over the waters as
low pressure deepens to our west and the pressure gradient
tightens. Small Craft Advisories are in effect for all waters
in southerly flow today into tonight. A few SMWs may be needed
over the waters tonight in association with any storms that move
over the waters. Winds turn west-southwesterly behind a cold
front late tonight into tomorrow. SCAs remain in effect through
the day tomorrow. A reinforcing cold front will cross over the
waters Friday evening. Winds will turn westerly behind that
front, and may potentially pick up a bit in magnitude as well. A
Gale Watch is in effect for all waters Friday night through the
daylight hours on Saturday. Winds should drop back to SCA and
potentially even sub-SCA levels Saturday night.

Gusty winds remain on Sunday with southwest winds gusting 15-20
knots across the waters. Small Craft Advisories are possible across
all waters for Sunday. Winds shift to west/northwest on Monday and
diminish to below Small Craft Advisory criteria.

&&

.TIDES/COASTAL FLOODING...
Southerly flow will increase through tonight. Light flow will
lead to a gradual increase in tide levels through the remainder
of the overnight, then stronger flow and approaching strong low
pressure will result in a more significant increase later today
into tonight. The highest tides are expected late tonight
through Friday morning, and this is when widespread minor to
localized moderate tidal flooding would be most likely. However,
if onshore flow is a bit stronger, tides could easily end up a
foot or so higher than currently forecast. This would result in
more widespread moderate tidal flooding (perhaps as early as
late tonight, with near major for the most vulnerable areas).

Westerly flow should cause a decrease in tide levels Friday
afternoon into Saturday, though the flow is west instead of
northwest which may result in some residual elevated water
levels sloshing around the Chesapeake Bay and tidal Potomac
River a little longer than is typical behind a front.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 8 AM EDT Friday for DCZ001.
     Coastal Flood Watch from Friday morning through Friday
     afternoon for DCZ001.
MD...Wind Advisory from 11 AM this morning to 11 PM EDT this
     evening for MDZ001.
     Coastal Flood Advisory from 7 PM this evening to 4 AM EDT
     Friday for MDZ011.
     Coastal Flood Watch from late tonight through Friday afternoon
     for MDZ011-014.
     Coastal Flood Advisory from 6 AM this morning to 2 AM EDT
     Friday for MDZ014.
     Coastal Flood Advisory from 4 PM this afternoon to 10 AM EDT
     Friday for MDZ016.
     Coastal Flood Advisory until 2 AM EDT Friday for MDZ017.
     Coastal Flood Watch from late tonight through Friday morning
     for MDZ017.
     Coastal Flood Advisory from 1 AM to 10 AM EDT Friday for
     MDZ018.
     Coastal Flood Advisory from 10 AM this morning to 4 AM EDT
     Friday for MDZ508.
     Coastal Flood Watch from Friday morning through Friday
     afternoon for MDZ508.
VA...Coastal Flood Watch from Friday morning through Friday
     afternoon for VAZ054.
     Coastal Flood Advisory from 4 PM this afternoon to 10 AM EDT
     Friday for VAZ057.
     Wind Advisory from 6 AM this morning to 8 PM EDT this evening
     for VAZ503.
     Wind Advisory from 2 PM this afternoon to 2 AM EDT Friday for
     VAZ507-508.
WV...Wind Advisory from 11 AM this morning to 11 PM EDT this
     evening for WVZ501.
     Wind Advisory from 6 AM this morning to 8 PM EDT this evening
     for WVZ505.
MARINE...Small Craft Advisory from 8 AM this morning to 6 PM EDT Friday
     for ANZ530>543.
     Gale Watch from Friday evening through Saturday afternoon for
     ANZ530>543.

&&

$$

SYNOPSIS...KJP
NEAR TERM...KJP
SHORT TERM...KJP
LONG TERM...AVS
AVIATION...KJP/AVS
MARINE...KJP/AVS
TIDES/COASTAL FLOODING...LWX