127
FXUS61 KLWX 290119
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
919 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 will remain off the New England coastline tonight
as low pressure tracks across northern Minnesota toward Lake
Superior. Low level southeasterly flow between these two
features will continue to advect higher dewpoint air into the
region, with dewpoints reaching the upper 60s to near 70 by
daybreak. Meanwhile, south to southwesterly flow at 850 hPa will
advect much warmer air into the area aloft. Dry conditions are
expected to persist overnight, but low clouds should eventually
form in response to strong moisture advection at low-levels.
With the southeast winds and increasing dewpoints, a mild
night is expected. Lows will range from the mid 60s to the west
of the Blue Ridge, to the lower 70s in urban areas along the
I-95 corridor.

&&

.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
Saturday 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 /01Z SATURDAY THROUGH WEDNESDAY/...
Onshore flow tonight into Saturday morning could bring some
lowered CIGs along/east of the Blue Ridge.

Prevailing VFR conditions are expected Saturday, with brief drops
to sub-VFR conditions Saturday afternoon into Saturday night as
showers and thunderstorms move across the area. Temporary drops
to sub-VFR will remain possible Sunday in association with
showers and thunderstorms as a cold front moves through the
area.

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

&&

.MARINE...
SCAs remain in effect for all waters tonight within
southeasterly flow. This SCA may potentially need to be extended
through much of Saturday within southerly flow. Additionally,
any storms that develop Saturday could produce damaging wind
gusts and need SMWs. While much of the thunderstorm activity is
expected to hold off until after dark, a stray thunderstorm or
two can`t be ruled out Saturday afternoon. Better chances for
thunderstorms and associated SMWs move over waters Sunday
afternoon into Sunday evening.

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 until 8 AM EDT Saturday for ANZ530>543.

&&

$$

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