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319
FXUS61 KLWX 030757
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
357 AM EDT Mon Jun 3 2024

.SYNOPSIS...
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Weak low pressure passes through the area today. Mostly dry
conditions are expected through Tuesday as weak high pressure
builds back into the region, but isolated to scattered showers
are possible in the afternoons and evenings. Shower and
thunderstorm chances return Wednesday through Friday as a series
of fronts cross the region.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Patchy fog has been developing near and west of the Blue Ridge
early this morning while lingering showers continue over eastern
Maryland. Patchy fog likely continues until burning off a few
hours after sunrise. Widespread dense fog is not currently
expected, but fog has been observed briefly as locally denser
at some sites (CHO got down to 3/4 mi).

Though there is weak upper ridging in place today into Tuesday,
lingering low-level moisture combined with a front stalled in
the vicinity could yield some isolated to scattered showers and
t-storms this afternoon and into the evening. Greatest coverage
will be primarily in the Shenandoah Valley and Virginia Piedmont
but will also be possible elsewhere. High temperatures reach
into the 70s to mid 80s this afternoon.

Fog likely returns again tonight, especially along and west of
the Blue Ridge, lows drop into the 60s to low 70s.
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&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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Guidance has trended wetter for Tuesday as high pressure off to
the northeast brings southeasterly onshore flow and moisture
into the region and a boundary stalls nearby. Though a weak
upper ridge will remain on Tuesday, shortwave energy approaches
from the west. Combining these factors, looks to be enough
moisture and forcing for isolated to scattered showers and
t-storms to develop in the afternoon and evening. As of now,
best chance will be along and west of the Blue Ridge with
showers likely initially developing along terrain. Thanks to
southeasterly flow, highs Tuesday rise into the mid-upper 80s
for much of the area.

For Wednesday, guidance has trended wetter as well, the warm
front moving into the area by Wednesday afternoon as a leading
shortwave swings through. Deterministic guidance has 600-800
J/kg of CAPE during this time, but less favorable shear. Overall
the system has recently trended faster, bringing the cold front
either to our doorstep or into the region by late Wednesday
night/early Thursday morning. Will continue to monitor severe
threat which will depend on this timing in relation to the
favorable shear and daytime heating, or lack thereof.
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&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
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A slow moving cold front and wave of low pressure exit east of the
area Thursday morning, with some scattered shower activity ongoing
across the area. In wake of the front, nearly unidirectional
westerly flow develops as a very large upper low approaches from the
west. Another round of scattered afternoon to early evening showers
and thunderstorms are forecast Thursday as a subtle mid-level
shortwave moves overhead. Highs reach the low to mid 80s.

The forecast becomes uncertain Friday into the weekend as models
diverge on the location and forward motion of the large upper low
over the region. The GFS maintains the low nearly stationary over
PA/NY through the weekend, which produces daily showers and
thunderstorms in our area. The ECMWF is much more progressive,
pushing the upper low east of the area on Saturday and bringing a
drier forecast. Both model ensembles paint a similar picture of
uncertainty. Thus, the current forecast has rain chances at 20-35
pct each day Friday through Monday, though expect this to change as
models start to converge on a potential solution in the coming
days.
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&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
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VFR conditions are expected to prevail today and Tuesday.
Isolated to scattered showers and thunderstorms are possible in
the afternoons and evenings, but coverage is being tamped down
by weak upper ridging. Storms that move over the terminals could
bring brief restrictions. Otherwise, patchy fog early this
morning and again tonight could bring MVFR or lower vsbys to CHO
and MRB. IAD could also see some reductions in vsby but with
less confidence, and only down to MVFR if so. Greater chance of
restrictions will be tonight.

Widespread showers and thunderstorms arrive Wednesday afternoon
and evening with warm frontal precip and an approaching upper
shortwave. Shower activity could extend well into Wednesday
night and possibly Thursday morning depending on the timing of
the cold front with this system. Terminals can expect
restrictions with convection moving through.

Another round of scattered showers and thunderstorms are possible
Thursday afternoon to evening. Any stronger thunderstorm that
moves over a terminal could produce a brief period of sub-VFR
conditions and gusty winds. A large upper level low pressure is
forecast to move atop the area Friday. This could lead to
additional thunderstorms Friday, but the forecast is very
uncertain at this time due to large model spread.
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&&

.MARINE...
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Sub-SCA winds are expected through Tuesday. Winds increase out
of the southeast Tuesday but are expected to remain sub-SCA. A
frontal system arrives on Wednesday with gusty southerly winds
over the waters approaching SCA criteria by Wednesday afternoon.
Timing of strongest winds will depend on the timing of a series
of fronts passing over the waters, but SCAs are possible
Wednesday afternoon into Thursday morning.

SCA conditions are possible in the open waters of the Chesapeake
Bay in wake of a cold front that crosses the waters Thursday
afternoon. Though, those west to southwest winds will be marginal
with peak gusts of 18-20 knots. Winds decrease Thursday evening and
are forecast to remain below SCA levels through Friday night.

Scattered showers and thunderstorms are forecast Thursday afternoon
and evening across all the waters. Any stronger storm could be
capable of producing wind gusts of 35 knots, in addition to
lightning strikes. Some thunderstorm chances continue into
Friday.
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&&

.TIDES/COASTAL FLOODING...
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Tidal anomalies are forecast rise slowly through mid week. For
today, any coastal flood impacts will be limited to the most
sensitive sites that reach Action Stage during high tide. As onshore
flow strengthens some locations could see minor flooding during the
Tuesday night to Wednesday morning high tide cycle. A weak cold
front crosses the area early Thursday, and the resulting west winds
are likely to cause anomalies to drop.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...EST
NEAR TERM...CAS
SHORT TERM...CAS
LONG TERM...KRR
AVIATION...CAS/KRR
MARINE...CAS/KRR
TIDES/COASTAL FLOODING...KRR