173
FXUS61 KLWX 110754
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
354 AM EDT Thu Jul 11 2024

.SYNOPSIS...
A brief reprieve in the excessive heat and humidity is expected
today within post-frontal west to northwest flow. Shower and
thunderstorm chances return Friday and Saturday especially east
of the Blue Ridge with a stalled front nearby. Weak high
pressure briefly builds back into the area Sunday then gradually
slides offshore Monday into Tuesday allowing the high heat,
humidity, and daily thunderstorm chances to return.

&&

.NEAR TERM /THROUGH TONIGHT/...
Drier conditions are expected today in the wake of our recent cold
frontal boundary which looks to stall across the Delmarva and
Virginia Tidewater region. An isolated shower or thunderstorm cannot
be ruled out over southern MD and the northern neck of Virginia as a
result through this morning and into the afternoon. Higher rain
chances return to these locations later this evening and into the
overnight hours as the stalled front wavers back across the region.

Most of us today will see a brief reprieve from the excessive heat
and humidity. High temperatures today east of the Alleghenies will
sit in the mid to upper 80s and low 90s with heat indices running
about the same. Dewpoint values will fall into the upper 50s and low
60s under post frontal light west to northwest (5-15 kts) flow
making it much more tolerable outdoors. Mid and high level clouds
this morning will give way to mostly sunny to partly cloudy skies
across the region. More cloud cover is expected south and east
toward southern MD and the Eastern Shore given the stalled front
nearby.

Unfortunately, the calm conditions do not last for long as the
stalled front eventually pushes back into areas along and east of I-
95 later this evening and into the overnight hours. This is due to
strengthening high pressure off the East Coast which will drive
onshore flow and the eventual push of the front back into the
region. Showers and thunderstorms will pick up in coverage late
tonight into early Friday morning starting in southern MD and the
northern neck of Virginia before gradually lifting toward the Blue
Ridge early Friday morning as the front sits nearby. Severe weather
is not expected although beneficial rainfall and perhaps a few
instances of poor drainage flooding are possible given the
efficiency of the rain with PWATS around 2"+. Lows tonight will
range from the upper 50s and low 60s west of the Blue Ridge where
drier air holds on with low to mid 70s along and east of I-95 where
the stalled front resides.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Showers and thunderstorms will continue to develop during the
day Friday and Friday evening along and east of the stationary
front. While we could be looking at an additional inch or two of
rainfall in southern Maryland, lesser amounts expected to the
west and northwest and on the cool side of the stationary front.
High temperatures Friday should be 7 to 10 degrees cooler with
temperatures in the lower 80s where cloud cover and rainfall is
widespread or plentiful, while warmer high temperatures expected
to reach upper 80s to near 90 in the west where rainfall will
be zero or very little and sunshine will be more.

As showers and thunderstorms are expected to slowly move east and
out of the CWA Saturday into Saturday night, temperatures will climb
right back up into the 90s, predominantly, with humidity increasing
again.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Excessive heat and humidity make a return Sunday into early next
week. Slightly drier conditions are expected Sunday into Monday with
hit or miss thunderstorm chances during the afternoon and evening
hours. Increasing precipitation chances by the middle part of next
week as another front and series of low pressure systems push
through the area.

Weak high pressure over the eastern Great Lakes will continue build
south into the Mid-Atlantic Sunday. This will nudge our stalled
frontal boundary back closer to the coast while decreasing shower
and thunderstorm chances across the region. Low end Pops capped less
than 20 percent will remain mainly east of I-95 where the washed out
front resides and over the terrain due to orographic lift during the
peak heating period. This is due to light west to southwest flow
overhead which should promote downsloping and a reduction in overall
forcing as well as low level moisture in the area. High
temperatures Sunday will climb back into the mid to upper 90s
east of the Blue Ridge. Heat indices will head back over the 100
degree mark during this time as well.

Much of the same can be expected Monday into Tuesday as weak high
pressure slides offshore and southwest flow builds moisture back
into the region. This will renew diurnally driven shower and
thunderstorm chances especially across the terrain. The coverage of
storms will remain isolated to scattered with the greatest uptick
coming Wednesday and Thursday as an upper level trough/front
approach the region. High temperatures will remain in the mid to
upper 90s to around 100 degrees east of the Alleghenies each
afternoon with heat indices around or above 100 degrees.


&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Prevailing VFR conditions are expected today in the wake of the
frontal boundary under light west to northwest flow. Showers and
thunderstorms return late tonight and throughout Friday especially
at terminals east of the Blue Ridge. The highest probabilities of
MVFR or lower conditions appears to be at KMTN, KBWI, KDCA, and
KRIC. Areas further west toward KIAD, KCHO, and KMRB will have the
opportunity for a few showers and thunderstorms, but overall
confidence decreases given a tighter gradient between the stalled
front/ low level moisture east of I-95 and slightly drier air
west of the Blue Ridge. Similar conditions are expected at these
same terminals Saturday although the coverage of showers and
thunderstorms will decrease Saturday afternoon and evening as
weak high pressure pushes in.

Prevailing VFR conditions are expected Sunday through Tuesday as
weak high pressure builds back into the region. Winds will turn
toward the west late Saturday before switching back to the southwest
Sunday into early next week. A few thunderstorms cannot be ruled out
at terminals along and west of the Blue Ridge although coverage
should be fairly sparse. High probabilities for thunderstorm
activity return to the forecast Wednesday and Thursday next week as
another front pushes into the area.


&&

.MARINE...
The recent cold front will stall toward the coastal Delmarva
today as winds shift toward more of a westerly direction.
Conditions will remain dry with an outside chance of an isolated
shower or thunderstorm over the lower waters of the bay. Sub-
SCA level winds out of the west are expected this morning
switching to the northwest and north later this afternoon. A
brief period of SCA level winds is possible over the open waters
late tonight into early Friday as the front wavers back across
the area.

Additional showers and thunderstorms look to accompany this front as
moisture increases once again Friday. Cannot completely rule out an
SMW if any strong thunderstorms approaching the marine zones.
Thunderstorm chances drop off this weekend as weak high pressure
builds into the region. Sub-SCA level winds expected during this
time.

&&

.TIDES/COASTAL FLOODING...
Tides will be on their way down over the next day or two as we will
be flip-flopping on the cool side then warm side of a stationary
front through Saturday night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 5 AM EDT early this morning for
     MDZ008.
     Coastal Flood Advisory until 4 AM EDT early this morning for
     MDZ508.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 5 AM EDT early this morning for
     ANZ530>533-537-539>541.
     Small Craft Advisory until 6 AM EDT early this morning for
     ANZ534-543.

&&

$$

SYNOPSIS...EST
NEAR TERM...EST
SHORT TERM...KLW
LONG TERM...EST
AVIATION...EST
MARINE...KLW/EST
TIDES/COASTAL FLOODING...KLW