182
FXUS64 KMEG 061022
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
522 AM CDT Mon May 6 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
Issued at 522 AM CDT Mon May 6 2024

Shower and thunderstorm chances are expected to become isolated
into this afternoon as an upper-level disturbance moves away from
the Lower Mississippi Valley. An active period of weather is
expected for Tuesday into Wednesday night as a series of troughs
move through the Mississippi and Ohio Valleys. Severe
thunderstorms are possible Tuesday afternoon into Tuesday evening,
and especially Wednesday night. Cooler and drier air is
anticipated for the upcoming weekend.

&&

.DISCUSSION...
(Today through Sunday)
Issued at 522 AM CDT Mon May 6 2024

GOES-16 satellite this morning show the remnants of an MCV
centered near St. Louis. Nocturnal convection developed near the
nose of a 35 kt low level jet. This resulted in strong to severe
thunderstorms and heavy rainfall overnight especially over north
Mississippi where a corridor of instability between 1000-1500 J/kg
and 35 kts of shear existed. Convective activity has since waned
over the past hour with showers and thunderstorms located over
north Mississippi and portions of West Tennessee near the
Tennessee River. Strong to severe thunderstorms through mid-week
remain the primary concern in this morning`s forecast issuance.

Short-term models suggest rain chances will gradually diminish
today in wake of the overnight convection as the atmosphere
stabilizes somewhat. Some CAMs indicate the potential for some
isolated showers and thunderstorms this afternoon. However,
confidence in occurrence and coverage remains low at this time as
shortwave ridging builds in across the Mid-South.

Additional showers and thunderstorms are expected to develop
across the Central and Southern Plains tonight as a mid-level
trough becomes negatively tilted and moves into the Middle
Mississippi Valley. This upstream activity is anticipated to
weaken as it moves towards the Mid-South late tonight into a
somewhat stable atmosphere. Instability is expected to increase
into Tuesday afternoon/evening with redevelopment of showers and
thunderstorms expected especially east of the Mississippi River.
The aforementioned surface-based instability combined with moderately
steep mid-level lapse rates and deepening shear suggest a
potential for strong to severe thunderstorms with large hail and
damaging winds as the main threats.

Confidence continues to increase with the potential for organized
severe thunderstorms across the Mid-South Wednesday into Wednesday
night as a shortwave mid-level trough rotates around an upper-
level low through the Middle Mississippi and Ohio Valleys.
Meanwhile, a surface low is expected to move across northeast
Missouri and northern Illinois. Favorable upper-level divergence
produced by the left exit region of a sub-tropical jet and perhaps
the right exit region of the polar jet combined with deep
directional and speed shear, very steep mid-level lapse rates, and
strong instability favor the potential for large hail, damaging
winds, and tornadoes. Colorado State University machine learning
guidance and St. Louis University CIPS analogs support the
potential for organized severe weather across the Ohio Valley and
Mid-South Wednesday afternoon and Wednesday night. At this time,
it appears the greatest threat for severe thunderstorms across the
forecast area will be Wednesday night as a capping inversion may
be in place across much of the Mid-South. This potential severe
weather event will be closely monitored over the next couple of
days. Stay tuned...

Long-term models indicate some residual showers and thunderstorms
will be possible on Thursday with cooler and drier air filtering
in for Friday into the upcoming weekend.

CJC

&&

.AVIATION...
(06Z TAFS)
Issued at 1113 PM CDT Sun May 5 2024

A shortwave is shifting across the Middle Mississippi River
Valley. Persistent showers and thunderstorms are approaching MEM
and will likely remain in the airspace for the next 2-3 hours.
Storms should be weakening as they approach MKL between 08-80z.
Cigs are expected to lower to IFR levels behind the line with
additional thunderstorm development possible through the night. We
should see a bit of a break in the morning before additional
convection develops tomorrow afternoon. Prevailing winds will
remain from the south to southwest generally 5-10kt through the
TAF cycle, although brief gusts are possible in association with
any thunderstorms. Showers and thunderstorms should taper off
after sunset.

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$

PUBLIC FORECAST...CJC
AVIATION...JDS