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551
FXUS61 KLWX 251406
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1006 AM EDT Sat May 25 2024

.SYNOPSIS...
A frontal boundary will dissipate near the Mason-Dixon Line
today. Another boundary settles to the north and remains there
through the holiday weekend. Eventually, a much stronger cold
front pushes through the region Monday into Monday night. A
secondary cold front moves in by mid-week before high pressure
builds in late next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Dry/stable conditions observed on 12Z IAD sounding, and a bit
less so at PBZ. Some mid and high level clouds are likely much
of the day due to upstream convective debris. A few showers and
storms may develop due to terrain circulations and lee troughing
this afternoon in the mountains, but the greater threat appears
to be after 5 PM as potential clusters of storms approach from
the upper Ohio Valley in association with a subtle shortwave
trough. Instability, shear, and lapse rates are all on the
modest end of the spectrum, but a few instances of wind damage
and hail can`t be ruled out with more organized structures.
There is some uncertainty on whether storms will survive east
of the Blue Ridge later this evening, but even if they do they
will likely be in a weakening state. Otherwise warm and muggy
conditions are expected with highs reaching the mid 80s for
most.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
Model guidance indicate significant height rises through the day
Sunday ahead of deepening trough over the western Great Lks.
While this should tend to suppress convective development, air
mass is expected to become moderately unstable by afternoon with
MUCAPE of ~1000 J/kg. Scattered thunderstorm development is
possible along a weak pressure trof. Some remnant MCS from the
OH Valley may also make it into the area during the overnight
hours Sunday night.

Memorial Day...Some remnant or decaying convection is possible
early in the morning. By afternoon, height falls and
strengthening sfc convergence along a deepening sfc trof is
expected to result in convective initiation with all modes of
severe weather possible before convection tries to evolve into
an increasingly organized line. This appears to be the most
significant severe wx event so far this convective season.
Despite expected relatively fast storm motions, isolated flash
flooding is also possible due to multiple rounds of convection.
Storms are likely to exit the area by 02Z Tue if not a little
sooner than that.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
CAPE decreases significantly behind the front Monday, though a
passing SW trough could bring additional rain showers Tuesday into
Wednesday. Does not look like a washout either day with weak sfc
high pressure underneath the upper level system.

Behind this wave, dew points will fall into 40s come next Thursday
with highs in the upper 60s to low 70s. This may be the least humid
day until September across the area.

Likely remaining dry into Friday before the next system brings the
potential for rain showers or thunderstorms next Saturday.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
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Best chance for t-storms today is at MRB toward late afternoon
or early evening. Looks like any activity moving toward the
metro areas later this evening will be in a weakening state, so
will be evaluating guidance as to whether a mention needs to be
made in the TAFs. Patchy fog is possible late tonight,
especially at MRB.

Shower and storm coverage is expected to be sparse Sunday with
weak high pressure. Widespread showers and thunderstorms
expected on Memorial Day with severe thunderstorms likely.

Prevailing VFR conditions are likely Tuesday into Wednesday, though
a passing shower is possible. Winds will become northwesterly at
about 10 kts.
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&&

.MARINE...
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Winds should remain below SCA until Sun night. Isolated t-storms
are possible this evening and again late Sunday. Widespread
showers and thunderstorms expected on Memorial Day, some of
which are likely to be severe and require SMWs. SCAs are likely
Monday through Monday night.

A passing shower is possible over the waters Tuesday into Wednesday.
Winds will be prevailing out of the NW about 10 kts, with gusts up
to 15-20 kts during the afternoon hours.
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&&

.TIDES/COASTAL FLOODING...
Water levels are expected to gradually rise into the weekend
given south to southeasterly warm advection. Many tidal sites
see their higher of the two high tides reach Action stage.
Further increases are likely into Monday/Memorial Day which
could lead to some coastal flooding.

&&

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

&&

$$

SYNOPSIS...LFR
NEAR TERM...ADS
SHORT TERM...LFR
LONG TERM...CPB
AVIATION...ADS/LFR/CPB
MARINE...ADS/LFR/CPB
TIDES/COASTAL FLOODING...LFR