255
FXUS61 KLWX 091345
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
945 AM EDT Sun Jun 9 2024

.SYNOPSIS...
A weak cold front will move through the area today. Low
pressure may develop off the coast during the first half of the
week. High pressure will build in from the west by Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
An increase in moisture aloft can be observed in the 12Z IAD
sounding with PW of 1.36in and mid level RH of 83%. This
increase in moisture from yesterday is attributed to the upper
level trough pivoting over the area from the Great Lakes. The cold
front mentioned in the previous discussion is currently moving
through the forecast area with showers and increased cloud cover
ahead of the front.Looking at recent satellite imagery, several
bands of clouds can be seen moving over the forecast area. This
trend will continue today as the front moves through the
forecast area. Otherwise, previous forecast remains on track.

Previous Discussion Follows:
An approaching cold front could spawn a couple of showers along
the Alleghenies toward daybreak today. This same front will
track southeast over the forecast area and bring additional
showers and perhaps a thunderstorm, primarily over southern
Maryland where the combination of good wind shear and limited
CAPE have a better coincidence. High temperatures will get into
the upper 70s to mid 80s for most while those at higher
elevations stay in the 60s to low 70s. Breezy northwest winds
will gust 20 to 30 mph at times in the afternoon before
diminishing overnight. Temperatures dip into the 50s to 60s
areawide tonight as dry conditions return.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
High pressure will build in over the region on Monday as winds
remain out of the northwest. Most of the area is expected to be
dry, but an upper level trough pivoting over the area will bring
a slight chance of precipitation to those along the Alleghenies
and in the southernmost portions of the area. High temperatures
will be slightly cooler in the wake of the cold front with
highs in the 70s (60s mountains) for most. Overnight low
temperatures will fall into the 40s to 50s for most with only
those in the metro areas staying in the low 60s.

High pressure will settle over the Mid-Atlantic Tuesday before
moving further offshore later in the week. Mostly sunny skies
are expected with highs in the upper 70s to low 80s for most
areas aside from the mountains where mid to upper 60s will be
more common.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The key players on the synoptic scale for the middle to latter
portions of next week are a compact upper low nearing the Desert
Southwest, a closed ridge across the Four Corners, and broad
longwave troughing from the Northern Plains to the northeastern U.S.
The period will consist of much warmer weather along with increasing
humidity levels. Surface high pressure remains in control through
Thursday while a stalled frontal zone persists near the southeastern
U.S. coast. Forecast conditions will be dry during this period,
accompanied by mainly southwesterly winds. This persistent warm,
moist advection will help raise dew points toward the latter half of
the work week. Additionally, temperatures really begin to soar into
Thursday and Friday as 90s become more commonplace.

Pronounced warming in the atmosphere will raise 850-mb temperatures
into the 19-21C range. Dry adiabatic mixing of this profile down to
the surface would yield area-wide highs in the low/mid 90s. The
effects of the humidity become more noticeable by Friday which
raises heat indices into the mid/upper 90s. At the same time,
convective chances increase ahead of an approaching cold front.
Based on the latest guidance, this frontal passage takes place
Friday afternoon/evening. Depending on the degree of instability and
timing of this cold front, some severe weather component may emerge.
At a minimum, showers and thunderstorms do return to the forecast on
Friday given the combination of the hot and humid air mass with
enhanced lift from the front.

High pressure builds in from the Great Lakes for the start of the
weekend. Although temperatures likely remain above average, the
shift to northwesterly flow will bring down the humidity. Based on
the latest ensembles, this pattern likely holds through the whole
weekend as well.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR conditions today through Tuesday night. Winds southwest
shifting northwest 10 to 15 knots gusts up to 20 knots today,
diminishing overnight. Winds northwest 5 to 10 knots Monday and
Monday night. Winds northwest around 5 knots Tuesday, becoming
light and variable Tuesday night.

Expect mainly VFR conditions for Wednesday and Thursday with surface
high pressure holding strong. Persistent south-southwesterly flow
will gradually moisten the atmosphere through the mid to late week
period. There could be some chance for patchy fog by Thursday night
given the moistening of the low-levels and light winds.

&&

.MARINE...
Small craft advisories remain in effect through the middle of
this evening. No marine hazards expected tonight through Tuesday
night. Winds south becoming northwest 10 to 15 knots up to 25
knots today and this evening. Winds remaining northwest around
10 knots later tonight through Tuesday night.

A shift to southerly winds are expected by midday Wednesday,
persisting through at least Thursday. There will be some periods of
channeling effects which could bring conditions to near Small Craft
Advisory levels. This is particularly the case on Wednesday night as
well as on Thursday evening into the night. Any convective chances
likely hold off until Friday with a cold front.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies remain above normal, and with winds briefly becoming
southwesterly or southerly early this morning, a further increase is
possible. Sensitive locations like Annapolis, Straits Point, and DC
SW Waterfront will be near minor flood stage with this morning`s
high tide cycle. After that, winds take on a west or northwesterly
direction behind a cold front, and no further flooding is expected
through mid-week.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 9 PM EDT this evening for
     ANZ530>543.

&&

$$

SYNOPSIS...KLW
NEAR TERM...AVS/KLW
SHORT TERM...KLW
LONG TERM...BRO
AVIATION...BRO/KLW
MARINE...BRO/KLW
TIDES/COASTAL FLOODING...BRO/ADS