772
FXUS61 KLWX 180800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Thu Jul 18 2024

.SYNOPSIS...
A cold front will slowly press south of the area today before
stalling Friday as high pressure builds to the north. The front
will return gradually back to the north this weekend into early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front bisects the area this morning, although the
moisture gradient is lagging farther behind. Some light showers
or sprinkles are occurring and will continue through the early
morning as primarily mid level ascent rides over the boundary.
This ascent will also produce plenty of mid level clouds, so
expect sunshine to be somewhat limited through the day.

As the morning progresses, a shortwave trough will approach from
the Tennessee Valley. This will result in increasing showers and
a few thunderstorms toward midday into the afternoon, primarily
across the southern tier of the area (Monterey to
Charlottesville and St. Marys County). However, there is a
slight shower chance as far north as approximately I-66/US-50.
Since instability will be meager north of the front, severe
weather is not expected. There could be some terrain-enhanced
rain totals that exceed an inch however per HREF LPMM.

The postfrontal airmass along with the cloud cover will result
in a notable cool down from recent days, although still close to
normal. Most areas will have highs in the mid 80s to near 90.

Rain chances quickly dwindle this evening as the shortwave
departs and the front moves farther south toward the Carolina
coast. The drier, less humid airmass will continue to advect
southeast, although a few clouds may linger, especially across
the south. This will likely be the coolest night of the forecast
period. Most locations will fall into the 60s, with 50s in the
western mountains, and lower 70s in the urban centers and
bayshore.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
High pressure will build over the Great Lakes Friday while the
front stalls across the Carolinas due to the strength of the
Bermuda high. While some models try to spit out a few showers
across southern areas, am comfortable saying the daytime should
remain dry (PoPs less than 15 percent) and that it will
definitely have the lowest chance of rain in the next seven
days. A mix of cumulus and cirrus will prevent a fully sunny sky
though. High temperatures will remain seasonable in the mid 80s
to near 90.

The front will gradually lift back to the north Friday night
into this weekend in response to an approaching trough from the
middle part of the country and the weakening high to the north.
A chance of showers will start spreading north late Friday
night. A more notable shortwave will approach Saturday though
and be effective at drawing moisture northward along with
providing ascent. Most areas will have a chance of rain
Saturday, although chances start decreasing northeast of the
Potomac with increased distance from the surface boundary which
will likely remain over central or southern Virginia. While a
few thunderstorms are possible, instability looks to be meager
and will limit their coverage and strength. Rainfall should
largely be beneficial. Rain chances will decrease Saturday night
as the shortwave departs.

The added cloud cover will likely hold high temperatures below
normal Saturday, especially across central Virginia. Increasing
dew points will lead to warmer overnights in the mid 60s to
around 70.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A stalled front near the Carolinas late this weekend will
become more and more of a local hindrance as the boundary moves
further north as a warm front to start the work week. Expect
routine chances for showers and thunderstorms Sunday into
midweek next week as a result of the front stalling out nearby
by Monday- Tuesday. Best coverage for showers and thunderstorms
looks to be in the Tuesday-Wednesday timeframe. Cannot rule out
isolated strong to severe thunderstorms during this pattern
given the convective parameters likely present during the
afternoon and evening hours.

Temperatures will be closer to average throughout the period with
upper 80s to low 90s expected each afternoon for the lower
elevations. Across the mountains, expected mid to upper 70s to be
more common throughout the early to mid week period. Overnight lows
will be in the mid 60s out west to mid to upper 70s closer to the
waters further east.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A cold front will continue to push south of the area this
morning. Any spotty showers/sprinkles should not impose ceiling
or visibility issues. It appears abundant mid level clouds will
prevent fog, and sub-VFR ceilings appear most likely south of
the terminals. There is a chance of a thunderstorm near CHO from
midday into the afternoon, but instability will be weak enough
that I am not confident in the occurrence of any lightning in
the vicinity at this time. Otherwise there will just be a slight
uptick in northerly winds through the day.

VFR conditions are expected tonight into Friday as high pressure
builds to the north. The front will stall to the south and
return north this weekend. Some sub-VFR ceilings could reach CHO
Friday night and could affect all terminals by Saturday night.
Showers and isolated thunderstorms are possible Saturday as a
disturbance passes.

VFR conditions are expected for the majority of the time Sunday into
Monday. Only caveat would be any isolated to scattered showers and
thunderstorms that approach the terminals may cause sub-VFR
conditions for a short duration. Winds out of the SE on Sunday will
turn more southwesterly by Monday with gusts up to 10 knots
expected.

&&

.MARINE...
A cold front will push to the south today with light west winds
becoming northerly. A few thunderstorms are possible near
southern Maryland this afternoon but seem unlikely to be
strong. A surge of northerly winds will work down the bay
tonight as high pressure builds to the north and cooler/drier
air arrives. Have issued an advisory for late tonight through
Friday morning for the bay and wider tributaries with gusts to
around 20 kt. Lighter winds are expected Friday and Friday
night as high pressure to the north remains in place.

The front will gradually move back north into this weekend. A
few thunderstorms will be possible Saturday. However, gradient
winds look to remain sub-SCA levels.

Sub-SCA conditions are expected Sunday into Monday with light winds
out of the southeast turning more southwesterly by Monday. Cannot
rule out an SMW if a strong thunderstorm were to cross the waters
during the afternoon and evening hours.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from midnight tonight to 10 AM EDT Friday
     for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from midnight tonight to 10 AM EDT Friday
     for ANZ530>534-537-539>541-543.
     Small Craft Advisory until 5 AM EDT early this morning for
     ANZ534-537-543.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...ADM
AVIATION...ADS/ADM
MARINE...ADS/ADM