-- Discussion containing changed information from previous version are highlighted. --
550
FXUS61 KRNK 270516
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
116 AM EDT Mon May 27 2024

.SYNOPSIS...
A series of disturbances will pass across the lower Mid-Atlantic
through Monday, triggering rounds of shower and thunderstorm
activity ahead of an approaching cold front. The front will
pass across the central Appalachians Monday evening, ushering in
drier and slightly cooler weather for much of the coming week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 745 PM EDT Sunday...

Key Messages:

1. Severe threat decreasing, transitioning to a heavy rain
threat.

2. Severe Thunderstorm Watch 317 has been trimmed, and the
remainder of 317 and Watch 318 continue until 9 and 11 PM,
respectively.

3. Still looks like another round of heavy showers/storms to
arrive overnight.

The severe weather threat continues across the forecast area,
but is mainly relegated to the Piedmont as a QLCS system
continues to bow out. Storms have delivered very strong winds,
large hail, and heavy rainfall, as well as prolific lightning.
Significant damage has been reported. This activity is on its
way out of the forecast area, but CAMs are still highlighting
another system already in progress over MO and IL reaching our
forecast area in the early morning hours. This system should
deliver less severe weather, but additional rainfall will
increase the flooding threat, which is already an issue in parts
of the area.



As of 230 PM EDT Sunday...

Key Messages:

1. A line of showers and thunderstorms will arrive from the
west this afternoon and evening. Severe Thunderstorm Watch
317 has been issued for the western half of the forecast area.

2. Another line of showers and thunderstorms may arrive early
in the morning on Memorial Day, though timing and intensity are
less certain.

3. Finally, isolated thunderstorms may be possible Monday
afternoon and evening, but confidence is low.

An impressive line of severe thunderstorms was moving rapidly
through the OH and TN Valleys, and will continue to push east at
around 40-50 mph through this evening. Numerous reports of 60+
mph wind gusts have already occurred with this MCS, and there is
a near continuous line of storms from Green Bay to Cincinnati
to Knoxville at this time. The system may weaken slightly as it
encounters the Blue Ridge, and west of here is where the Severe
Thunderstorm Watch has been issued until 9 PM. To the east,
still expect storms to move through between 7 to 10 pm. There
is a chance the Watch may be expanded downstream to include the
Piedmont.

Current temperatures were in the 70s and 80s, with dew points
in the upper 50s to upper 60s. This has yielded MLCAPEs in the
1500-2500 J/kg range, with DCAPEs maxed out in our northern NC
counties around 1100 J/kg. Wind shear in the lower levels is
about 30 kts between the surface to 3km, and bulk shear is
around 45 kts. Thankfully there is little directional shear, so
this does not look like a big tornado day, but spin ups along
the front edge of the MCS may turn into brief tornadoes. The
main concern here will be damaging winds, heavy downpours
leading to localized flooding, and intense lightning.

With it being Memorial Day weekend, plenty of people are
outside, and we urge you to pay attention to this rapidly
evolving weather scenario today and tomorrow. Remember to head
indoors and stay away from water when lightning is near, and
have multiple ways to get warnings.

By 10 pm, the severe threat will temporarily diminish as the
line passes out of our area to the east, bringing a brief lull
in the organized activity, with only residual showers to contend
with. However, decent agreement exists in the rapid update
weather forecast models that another line of storms will
approach from the west during the predawn hours Monday/Memorial
Day and shift east, sweeping east-southeast by mid morning.

Finally, there is a chance for some redevelopment of
thunderstorms in the afternoon and evening Monday, but believe
the morning convection may impact and degrade this, so
confidence in that is low.

Expect early morning lows to start Memorial Day to range from
the low to mid 60s, and highs to reach the mid 70s to low 80s
for the mountains, and the mid to upper 80s for the Piedmont.

Overall confidence in the near term is moderate.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
As of 215 PM EDT Sunday...

Key Messages:

1: Low chance of lingering storms in the wake of a front Monday
night

2: Quiet, breezy, and cool Tuesday onward

A front will have mostly made its way through our CWA and into
central VA by Monday night. A few lingering post-frontal showers
and storms could continue to crop up, but the main line with
most of the severe potential will have occurred earlier in the
day. Tuesday, Wednesday and Thursday will all have more or less
similar weather conditions. Surface high pressure will gradually
move down from the western Great Lakes and over the Mid-
Atlantic, will suppress precip chances. In the mean time we will
be in the western half of a mid- level trough, wherein a few
weak embedded shortwaves may pass through. This would only serve
to amplify cloud cover in the mountains and perhaps spawn an
isolated shower or two.

Temps will cool into the 60s for the mountains and mid to upper
70s for the Piedmont. Fairly cool for late May/early June.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 230 PM EDT Sunday...

Key Messages:

1: Low confidence in timing of next frontal system over the
weekend

Surface high pressure will remain in control of weather and
suppress precip through Saturday. This will keep things cool
with light breezes and scattered clouds. The next front could be
expected at earliest on Sunday morning. That solution is a bit
of an outlier amongst long range models. Most don`t have the
next front impacting the Mid-Atlantic until late Sunday or into
Monday. Also unclear what the potential impacts with this front
would be, though given the fact that it is early June, a frontal
passage generally includes thunderstorms.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 120 AM EDT Monday...

Early this morning, localized LIFR conditions were reported at
KLWB and areas of dense fog will be possible in mountain river
valleys ahead of an approaching line of thunderstorms across
eastern KY as of 1 AM EDT.

While some weakening is expected with this approaching line of
storms, wind gusts to 30 knots are possible, especially at KBLF
shortly before dawn. These storms will also bring a brief
period of IFR/MVFR conditions in the mountain sites
(KLWB/KBCB/KBLF) before conditions improve by mid to late mid
morning.

Another line of storms is expected to re-develop during the
afternoon hours Monday with KDAN the most likely terminal
impacted. Confidence is lower for these storms to impact KLYH.

Gusty southwest winds are expected this afternoon before fading
Monday night with pockets of IFR/MVFR fog possible in the
mountains early Tuesday morning.


EXTENDED AVIATION OUTLOOK...

A front will cross through the area late Monday into early
Tuesday, turning winds to the northwest and eventually bringing
drier air to much of the area. A low chance for showers and
thunderstorms will be possible across WV Tuesday and Wednesday,
otherwise VFR. VFR everywhere Thursday.

Patchy fog with periods of MVFR/LIFR will be possible in the
mornings near mountain and river valleys.
-- End Changed Discussion --

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$

SYNOPSIS...NF/SH
NEAR TERM...SH
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...PH