257
FXUS61 KLWX 040759
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 AM EDT Sat May 4 2024

.SYNOPSIS...
A stalled frontal boundary will remain draped to the south of
the forecast area throughout the weekend, bringing on and off
showers and possible thunderstorms. A secondary cold front will
move through the area on Monday before lifting as a warm front
on Tuesday. This will bring a prolonged period of unsettled
weather through next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front will remain stalled just west of the forecast area
throughout the day, bringing rain showers and perhaps a rumble
of thunder. Onshore flow will provide plenty of moisture for
cloudy skies, rain showers, and drizzle throughout the day.
Temperatures will be noticeably cooler today with highs in the
mid 50s to mid 60s. Cooler conditions combined with plenty of
cloud cover will hinder thunderstorm development. WPC has the
westernmost portions of the forecast area in a marginal risk for
excessive rainfall. Isolated instances of flooding are
possible, though dry antecedent conditions and 24-hour QPF
values less than an inch will lead to most of the rainfall being
beneficial.

Rain showers continue overnight with thunderstorm chances
dwindling this afternoon. Moisture aloft will deepen overnight,
leading to heavier rainfall overnight. Overnight low
temperatures will be in the 50s areawide.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The aforementioned cold front stalled to our south, will lift
through the forecast area on Sunday. This will bring noticeably
warmer temperatures with highs in the 60s to low 70s throughout
the area. Additionally, rain shower and thunderstorm chances
will continue both Sunday and Monday. Thunderstorm chances will
peak in the afternoon as instability increases with SPC having
the forecast area in a general thunder risk each day.

High temperatures will continue to warm on Monday due to
southerly flow ushering warm air. High temperatures will be in
the 70s to low 80s areawide. Those at highest elevations will
stay in the upper 60s throughout the day. Overnight low
temperatures will stay in the upper 50s to low 60s each night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Conditions will remain active through the long term period. A potent
shortwave trough and associated area of low pressure will track
across the Upper Midwest toward the western Great Lakes on Tuesday,
and then across southern Ontario/Quebec on Wednesday. A surge of
warm/moist advection will ensue at low levels in response on Tuesday
as a warm front lifts northward through the area. Afternoon showers
and thunderstorms appear likely on Tuesday in response to the
combination of daytime heating and low level warm/moist advection on
the synoptic scale. High temperatures on Tuesday should reach into
the upper 70s and lower 80s.

Low-level forcing for ascent decreases somewhat on Wednesday as we
move into the open warm sector and low-level flow turns westerly.
Thunderstorms will be possible again Wednesday afternoon, but the
coverage of storms should be considerably lower than Tuesday. In
westerly low-level flow, a lee trough may serve as a potential focus
for the development of storms. It will be noticeably warmer on
Tuesday, with high temperatures expected to be in the mid-upper 80s.

A prominent shortwave will eject eastward from the Plains toward the
Ohio Valley/Great Lakes on Thursday. An associated area of low
pressure will track toward the northern Ohio Valley toward PA and NY
by Thursday evening. This system will act to increase large scale
forcing for ascent across the area, while also strengthening the
wind field through the low-mid levels. As a result, showers and
thunderstorms are expected again Thursday, some of which may be
strong to severe in nature. High temperatures on Thursday are
forecast to reach into the upper 70s to mid 80s.

Model solutions begin to diverge by Friday, with some models driving
a cold front southeastward through the region Thursday night, while
others hold off on the frontal passage until Friday night. As a
result, a wide range of potential forecast outcomes exist. If we`re
post cold frontal on Friday, we`d have much cooler temperatures, and
dry conditions. However, if the front remains upstream of the area,
we`d have another day with warm and humid conditions, as well as
additional chances for showers and thunderstorms.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
Onshore flow will bring reduced ceiling heights and plenty of
cloudcover throughout the day today. MVFR to IFR conditions are
expected throughout the day as a stalled frontal boundary
continues rain and drizzle through the overnight. Winds remain
out of the east with gusts staying 10-15 knots possible at all
terminals except for CHO, where winds will remain lighter.
Tonight, heavier precipitation rates may lead to sub-IFR
conditions.

Precipitation and thunderstorm chances continue Sunday with IFR
flight conditions expected throughout the morning. Flight
conditions possibly improve to MVFR Sunday afternoon, through
dense fog and reduced CIGs could bring renewed chances for
IFR/sub-IFR conditions. Winds shift to southeasterly on Sunday,
blowing less than 10 knots. Unsettled conditions continue as we
head into the week as a cold front approaches from the west.

Prevailing VFR conditions are expected on Tuesday and Wednesday, but
temporary drops to sub-VFR conditions may be possible in any
thunderstorms. Winds will generally be out of the east on Tuesday,
before turning out of the south Tuesday night into Wednesday.

&&

.MARINE...
A Small Craft Advisory remains in effect through tonight for
the Chesapeake Bay with east winds blowing 10 to 20 knots.
Gusts up to 25 knots are possible. Winds increase for the Upper
Potomac and Upper Chesapeake Bay tonight, with SCA conditions
expected. Showers and perhaps a thunderstorm are expected
throughout the weekend as a warm front moves over the waters and
a cold front approach from the west. Winds shift to southerly
on Sunday and are expected to remain below SCA criteria as we
head into the week.

Sub-SCA level winds are expected in easterly flow on Tuesday, and
then in southerly flow Tuesday night into Wednesday. SMWs may be
possible either day if thunderstorms pass over the waters.

&&

.TIDES/COASTAL FLOODING...
Anomalies have started to rise in easterly flow overnight.
Persistent easterly flow is expected through Saturday night, with
winds turning south to southeasterly on Sunday. Tides are expected
to remain elevated through the weekend, with Minor flooding possible
in many locations. Moderate flooding may also be possible at
Annapolis and Straits Point, where a Coastal Flood Watch is in
effect for Saturday night. Water levels may begin to decrease during
the day Monday as winds turn southwesterly

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 8 AM EDT this morning for DCZ001.
MD...Dense Fog Advisory until 8 AM EDT this morning for MDZ001-501.
     Coastal Flood Advisory until 5 PM EDT this afternoon for
     MDZ014.
     Coastal Flood Watch from late tonight through Sunday morning
     for MDZ014.
     Coastal Flood Advisory until 2 PM EDT this afternoon for
     MDZ017.
     Coastal Flood Watch from this evening through Sunday morning
     for MDZ017.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT Sunday for ANZ530>534-
     537>543.
     Small Craft Advisory from 6 PM this evening to 6 AM EDT Sunday
     for ANZ536.

&&

$$

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