-- Discussion containing changed information from previous version are highlighted. --
926
FXUS61 KLWX 261357
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
957 AM EDT Sun May 26 2024

.SYNOPSIS...
A warm and humid air mass will persist through Memorial Day.
A strong cold front will push through the area Monday night.
A secondary cold front moves in by mid-week before high
pressure builds in late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Patchy fog and low clouds are dissipating. A weak boundary is
actually well south of the area with north/northeast winds as
far south as southern Virginia. Expect this boundary to evolve
northward this afternoon with winds turning to the southeast.
There should be a somewhat stabilizing influence until that
time, although once convective temperatures are breached,
isolated convection will become possible. The bay breeze and
terrain circulations still appear to be the primary driver of
development. What happens tonight will largely be influenced by
what happens upstream today. Any severe weather threat, whether
with the afternoon or nighttime activity, appears to be marginal
at best due to modest instability and shear. High temperatures
will be in the mid to upper 80s.

Previous discussion:

Low-mid level height rises are expected through the day today
which should help suppress convective cvrg and keep any activity
disorganized and short-lived. Despite the ridging, a weak
pressure trof remains over the area, remnant outflows from
yesterday`s evening convection, and any bay breeze may be just
enough to spark isold random convection about anywhere. Best
chance would be over the ridges and along the bay breeze.

A large convective complex is likely to evolve across the OH
Valley tonight and likely cross the Appalachian region after
midnight. While this complex is likely to weaken with time, some
guidance show the complex remaining strong overnight as it
moves across central VA and the I-64 corridor.
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&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Memorial Day...Large scale ascent and strengthening sfc
convergence along a pre-frontal trough is expected to generate
widespread showers and thunderstorms from Noon through about
8PM. Environment will be favorable initially for HP supercells
capable of producing isold tornadoes with additional t-storm
activity congealing quickly into an organized complex as shown
by simulated satellite imagery from various global models.
Damaging winds will be the primary hazard, but a couple of
tornadoes can`t be ruled out. The model signal for heavy rain
has decreased somewhat since the past couple of days. Eastern
areas, particularly central and northeast MD, would be at
greatest risk of any flooding once thunderstorm complex evolves.
Fast storm motions of 30-35 kt should keep this threat isold at
best. Front pushes quickly east of the area after 00Z Tue with
thunderstorm threat ending.

Additional shortwave energy moving around the base of the upper
trough will keep low-topped showers in the forecast through
Tuesday.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Mid-level cyclonic flow will allow for NW flow through much of the
long term - resulting in lower heights and a period of below normal
temperatures with low relative humidity.

The last of a series of shortwaves will be departing on Wednesday,
with a few showers or even a thunderstorm possible. This feature
will also have an accompanying weak sfc cold front. Tds will fall
into the mid-upper 40s for Thursday and Friday - making it feel more
like fall wx than that of late May in the Mid-Atlantic. A favorable
pattern for radiational cooling will develop Wednesday night through
Friday night. Overall, lows will be in the 40s to low 50s for most.
The typical high elevation cold pockets could definitely make a run
at 32F.

H5 heights start to rise by next weekend with moisture returning to
the area. Lots of spread, but have chance POPs again for next
Saturday into Sunday.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
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Isolated thunderstorms may develop over the terrain and along
the bay breeze this afternoon, but appear too sparse/sporadic in
nature to include in the TAF. Remnant thunderstorms may reach
the area this evening or overnight -- generally decreasing
chances with eastward extent. While uncertain, will consider
adding a thunderstorm mention if consensus increases in
timing/occurrence. MVFR to IFR ceilings are likely to develop
late tonight and may persist through late morning Monday.

Severe thunderstorms are likely Monday afternoon with the
primary hazard being damaging wind gusts.

Prevailing VFR conditions are likely Wednesday, though a passing
shower is possible. VFR Thursday. Winds will become northwesterly at
about 10-15 kts Wednesday before decreasing Thursday.
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&&

.MARINE...
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Southerly winds are expected to increase tonight into Memorial
Day as pressures fall in advance of a strong cold front. SCAs
have been issued for this time frame. SMWs will be required on
Memorial Day due to likelihood of severe thunderstorms.

A passing shower is possible over the waters Wednesday. Winds will
be prevailing out of the NW about 10 kts, with gusts up to 15-20 kts
during the afternoon hours behind the secondary cold front.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
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Threshold minor flooding could occur at DC SW Waterfront this
morning. With increasing south/southeast flow, there will be a
higher chance of minor flooding at multiple locations Monday
morning.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
-- End Changed Discussion --

&&

$$

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