-- Discussion containing changed information from previous version are highlighted. --
742
FXUS61 KLWX 081432 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
1032 AM EDT Wed May 8 2024

.SYNOPSIS...
Showers and thunderstorm chances continue through Thursday with
multiple waves moving through the Mid-Atlantic. A strong cold
front will bring increased chances for severe and flooding
impacts Thursday into early Friday. Precipitation chances
decrease behind the front going into the weekend with cooler
temperatures and high pressure nearing the Mid-Atlantic.

&&

.NEAR TERM /THROUGH TONIGHT/...

-- Changed Discussion --
Cloud cover from remnant MCS from overnight continues to show
signs of dissipation with clearing expected to occur across
northern areas. Guidance indicate increasing subsidence later
today with 925 and 850 mb dewpoints forecast to come down
significantly during the afternoon and evening on stregnthening
westerly flow. Any threat for thunderstorms appears to be along
and south of I-64 in central VA.

By tonight, clouds will increase from the west ahead of the
approaching cold front moving in from the Ohio Valley. Rain
chances will increase from west to east, especially after
midnight, and continue through the night and into Thursday
morning.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Increasing showers and isolated thunderstorms will continue Thursday
morning ahead of the cold front passage. Expect overall QPF to be
0.50 to 1" with localized higher amounts, especially in heavier
downpours and thunderstorms. Isolated instances of flooding will be
possible, given the anomalously high PWATs coupled with antecedent
moist conditions over the last week, especially across areas along
and west of the Blue Ridge Mountains. A fairly sharp instability
gradient may develop east of the Blue Ridge just ahead of the cold
front Thursday afternoon. There is some uncertainty with this given
any earlier convection/cloud debris from early convection late
tonight into early Thursday. Should there be a lull with increasing
breaks in the clouds, then some thunderstorms may develop and become
strong to even severe. Main hazards will be damaging winds along
with large hail of 1 inch diameter or greater as a result of steeper
lapse rates.  The best chances for thunderstorms will likely be
across the VA Piedmont into southern MD. Afternoon highs will be in
the upper 60s to low 70s across the MD/PA border, with low 80s
further south across central VA.

Showers and isolated thunderstorms will linger early Friday, with
showers continuing throughout much of the day as a result of the
departing low pressure system off to the north. Cannot rule out an
isolated thunderstorm Friday afternoon. Highs will cooler as a
result of northwest flow, with mid to upper 60s across most areas
with even mid 50s across the Allegheny Front. NW winds will be
gusting 20 to 25 knots during the afternoon on Friday, with higher
gusts possible along the ridges.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Longwave troughing will remain in place across the eastern US
this weekend. On Saturday we`ll start the day off between one
shortwave departing offshore, and another digging down the
backside of the longwave trough into the Ohio Valley. The latter
shortwave will pass overhead Saturday night into the day
Sunday.

Conditions should start off mostly sunny on Saturday within the
subsidence behind the departing shortwave. Clouds and eventually
showers will be on the increase as we progress through the afternoon
as large scale ascent ahead of the next shortwave starts to
overspread the area. Chances for showers will continue through
Saturday night and into the day Sunday as the upper trough axis
moves overhead. High temperatures this weekend are forecast to reach
into the upper 60s and lower 70s, while low temperatures will
generally be in the 40s to lower 50s.

Upper troughing will progress off to our east early next week,
allowing heights to start rising aloft. Such a pattern will lead to
drier conditions and a warming trend in temperatures. Highs are
expected to reach into the low-mid 70s on Monday, and into the mid-
upper 70s on Tuesday.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Just high clouds today with a slight chance of a thunderstorm
mainly at KCHO.

Widespread showers and thunderstorms are likely Thursday, with some
strong to severe storms possible for the afternoon and evening
hours. Best chances for this to occur would be across the I-95
corridor terminals. VFR conditions are likely outside of the
thunderstorm activity. These conditions will likely continue into
Friday with gusting NW winds 20 to 25 knots throughout the day.

Prevailing VFR conditions are expected at the terminals this
weekend, but passing showers could lead to temporary drops to sub-
VFR either day. Winds are forecast to be out of west to southwest on
Saturday, and then out of the northwest on Sunday.
-- End Changed Discussion --

&&

.MARINE...
Westerly winds may near SCA criteria this afternoon, especially
across the northern bay and upper tidal Potomac. There are still
uncertainties with this but will continue to monitor the trends for
any needed issuances. Cannot rule out an SMW across the southern
water especially this afternoon with any strong thunderstorms that
cross the waters but confidence is low in this occurring.

SCAs are possible Thursday and Friday as a result of southerly
channeling. SMWs will be possible Thursday afternoon ahead of a cold
front passage bringing heavy showers and thunderstorms over the
waters.

Winds may near low-end SCA values in west to southwesterly flow on
Saturday, and then again in northwesterly flow on Sunday.

&&

.TIDES/COASTAL FLOODING...
Water levels remain elevated in southerly flow this morning. Coastal
Flood Advisories are in effect for the ongoing tide cycle at
Annapolis, Straits Point, and DC. Westerly winds should allow water
levels to decrease this afternoon. Winds turn southerly again late
tonight into tomorrow morning, which could lead to additional Minor
flooding at the most sensitive sites.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...Coastal Flood Advisory until 11 AM EDT this morning for DCZ001.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ530>532-535-536-538>540.
-- End Changed Discussion --

&&

$$

SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...ADM
LONG TERM...KJP
AVIATION...LFR/KJP
MARINE...LFR/KJP
TIDES/COASTAL FLOODING...