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268
FXUS61 KLWX 031354
AFDLWX

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

.SYNOPSIS...
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Spotty shower and thunderstorm chances will continue through Tuesday
as low pressure pushes offshore and weak high pressure builds back
into the region. More widespread shower and thunderstorm activity
arrives Wednesday and Thursday as a series of fronts cross the
region. Precipitation chances decrease in the wake of the front
Friday into Saturday before another front and series of disturbances
impact the area early next week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Overall a similar theme to the forecast to what we saw on Sunday for
the start of the new workweek. Weak upper level ridging aloft
combined with high pressure offshore will lead to limited
coverage for showers and thunderstorms today through Tuesday.
Even with that said, there should be just enough low level
moisture combined with a stalled front and weak low pressure
system passing to the south and east to touch off a few showers
and perhaps a thunderstorms during the peak heating period.
Coverage will mainly be confined to the mountains and in areas
along and south of I-66/US-50 where better lift along the
stalled front can be found. Any thunderstorms look to weaken
after sunset with just a few passing showers during the front
half of the overnight period. Patchy fog is possible in
particularly across the river valleys and right along the bay.
Areas that do see the rain will also see the potential for fog
development.

Highs today will remain at or above normal in the upper 70s and low
to mid 80s. Lows tonight will fall back into the mid to upper 60s.
Mountain locations will remain in the 40s while metro centers/bay
locations sit around 70 degrees.
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&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
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.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
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.

&&

.MARINE...
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.

&&

.TIDES/COASTAL FLOODING...
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.

&&

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

&&

$$

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