338
FXUS61 KLWX 281905
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
305 PM EDT Fri Jun 28 2024

.SYNOPSIS...
High pressure builds in from the west today before pushing offshore
late tonight into Saturday morning. A warm front lifts through the
region on Saturday which will bring showers and thunderstorms back
to the region. A cold front will then push through on Sunday,
bringing yet another chance for afternoon showers and thunderstorms.
High pressure then returns for the early portion of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
High pressure centered off to the north is allowing for mostly
dry conditions across the area this afternoon and evening. A
mid-level cumulus field will continue throughout the day,
especially further south, more distant from the area of high
pressure. Cannot rule out a few isolated showers across portions
of central VA later this afternoon and evening but the
probabilities are pretty low. Afternoon highs will top out in
the low to mid 80s for the lower elevations with slightly cooler
temperatures across the mountains. Overnight lows will drop
down into the mid to upper 60s with increasing clouds ahead of
the next disturbance poised to affect the area for the
weekend.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
The area of high pressure will move further east Saturday morning
with a warm front approaching the Mid-Atlantic from the south. A
much warmer airmass and increasing moisture will allow for increased
precipitation chances by late Saturday afternoon and evening. The
best opportunity for showers and thunderstorms will be confined
mostly to areas along and west of the Blue Ridge and Catoctin
Mountains with the best chances across our far northwestern
counties. Increasing instability and shear across the aforementioned
areas will allow for some of these storms to be strong to severe
with the mostly likely hazards being damaging winds and an isolated
tornado. Timing of the showers and storms being late in the evening
may limit coverage of the precipitation but there still may be
enough instability during the evening hours to allow for convective
initiation. Highs on Saturday will top out in the upper 80s to low
90s. With the warm front passing through the area later in the day,
overnight lows will only get down into the low to mid 70s for the
lower elevations and upper 60s for the mountains.

For Sunday, the associated cold front will cross through the area
during the day. Instability may be a bit more favorable compared to
Sunday with increasing dewpoints, especially across the far eastern
areas. Strong to severe thunderstorms will be possible Sunday
afternoon/evening, especially along and east of the Blue Ridge
Mountains. The main hazard will be damaging winds and maybe some
hail. The other story on Sunday will be the heat, as areas east of
the Alleghenies will be in the low to mid 90s with heat indices
getting close to or exceeding 100 degrees, especially across
portions of central VA. There is still uncertainty with any
potential for headlines to be issued given the potential convection
and ongoing cloud debris that may limit the temperatures and heat
indices getting to criteria. After the cold front passes during the
day on Sunday, much cooler air will be ushered in with 50s and 60s
across the lower elevations and even upper 40s possible across the
Allegheny Front.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Strong high pressure will build across the area Monday
and Tuesday. Temperatures will be slightly below normal with
comfortable dew points in the 50s. The high will move offshore by
Wednesday with warmer and more humid air starting to return.
However, ridging aloft should limit convective chances, with only a
small chance of showers and thunderstorms over the mountains.

Heat and humidity return in earnest Thursday (Independence Day) and
Friday with forecast high temperatures well into the 90s and dew
points in the 70s (potentially resulting in heat index values over
100). While the main frontal zone will remain north and west of the
area, the heights aloft will flatten. Combined with lee troughing,
there will be enough forcing and instability for at least scattered
shower and thunderstorm activity each day.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Mostly dry conditions continue today as high pressure passes to the
north. Winds will slowly turn out of the SE by late this afternoon
with a brief lull before increasing late tonight.

Onshore flow tonight into Saturday morning could bring some lowered
CIGs along/east of the Blue Ridge, which could particularly impact
CHO. Lowered VSBY is possible, but winds are expected to be
prominent enough to keep fog threat pretty low.

Sub-VFR conditions are likely Saturday with any showers and
thunderstorms that move across the terminals. A warm front lifts
through the area in the morning/afternoon with some shower activity
expected, and more is expected in the afternoon and evening with the
potential for strong to severe storms. Sub-VFR continue into Sunday
with showers and thunderstorms expected with a cold frontal passage,
though likely improve behind the cold front.

No significant weather expected Monday through Wednesday as high
pressure moves across the area.

&&

.MARINE...
SCAs remain in effect over the lower waters of the Potomac River and
central Chesapeake Bay through the remainder of the day and into
tonight. The remaining zones will see SCA winds build back in later
this evening and through the overnight hours as a pressure gradient
tightens across the Mid-Atlantic as high pressure moves further
east.

Winds strengthen late tonight into early Saturday with a warm front
moving north. Additionally, any storms that develop Saturday could
produce damaging wind gusts and need SMWs. There is a non-zero
threat for waterspouts as well. Both of these threats seem greatest
in the northern portions of the waters at this time.

Northerly winds may continue to result in Small Craft Advisory
conditions through Monday afternoon, with a diminishing trend
overnight. Winds should be lighter Tuesday as high pressure moves
over the area. Southerly winds develop Wednesday, with some
potential for advisories, especially toward evening as channeling
increases on the bay.

&&

.TIDES/COASTAL FLOODING...
With prevailing north to northeasterly winds, tidal anomalies remain
low as they current average between 0.20 to 0.50 feet. Today`s winds
shift to mainly east-southeasterlies which allow some rise in water
levels. A large rise ensues over the weekend give the stretch of
southerly flow. A number of tidal sites start to push into Action
stage, with Annapolis and Havre de Grace currently forecast to hit
minor late Saturday night/early Sunday. Expect a cold front to track
through Sunday evening which helps usher much of the additional
water back toward the south heading into the new work week.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 7 PM this evening to 8 AM EDT
     Saturday for ANZ530>533-535-538>542.
     Small Craft Advisory until 8 AM EDT Saturday for ANZ534-536-
     537-543.

&&

$$

SYNOPSIS...ADM
NEAR TERM...ADM
SHORT TERM...ADM
LONG TERM...ADS
AVIATION...ADS/ADM/CAS
MARINE...ADS/ADM/CAS
TIDES/COASTAL FLOODING...LWX