068
FXUS64 KMEG 251120
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
620 AM CDT Sat May 25 2024

...New AVIATION...

.SYNOPSIS...
Issued at 415 AM CDT Sat May 25 2024

Showers and thunderstorms will continue over the Midsouth today,
though weak upper level ridging will limit coverage. A few storms
may still reach severe limits this afternoon, with large hail and
damaging winds the primary threats.

Severe weather chances will increase Sunday afternoon over northeast
Arkansas, the Missouri bootheel and northwest Tennessee. Large
hail, damaging winds and a few brief tornadoes will be possible.
The severe weather threat will continue Sunday evening over the
remainder of the Midsouth, as storms move to the southeast ahead
of an advancing cold front. The storms should exit north
Mississippi overnight Sunday night.

Less humid weather is forecast across the Midsouth on Memorial
Day. Only isolated showers and thunderstorms are expected east of
the Mississippi River.

&&

.DISCUSSION...
(Today through Friday)
Issued at 415 AM CDT Sat May 25 2024

09Z / 4 AM CDT surface map showed a cold front from St. Louis to
Joplin, Missouri. A prefrontal pressure trough was located over
southeast Missouri. Storms fired late Friday evening near this
pressure trough, but have since weakened since moving off the
boundary into northeast Arkansas. To the south, a bowing linear
MCS has passed from east central Arkansas into west TN. This
activity briefly weakened, but intensified as it lifted to the TN
River, aided by a 50 KT low level jet. The HRRR and NAM depict a
significant reduction in 925mb inflow and storm coverage toward
12Z.

Thunderstorm chances for the remainder of the day will limited by
weak ridging aloft. This ridging will also serve to displace EML
to the north, weakening convective inhibition, especially over
north Mississippi. Most of the Midsouth will see midlevel lapse
rates moderating below 6 C/km, lessing the large hail threat
through tonight.

Severe weather chances will return Sunday, as the midlevel ridge
lifts off the east. Diffluent flow aloft and midlevel height
falls will sufficiently weaken for convection to grow south from
an ongoing MCS over the lower Ohio Valley Sunday afternoon.
Storms will be likely from northeast Arkansas through northwest
Tennessee during peak afternoon heating. HRRR soundings across
this area depict midlevel lapse rates 7-8 C/km and surface-based
CAPE near 3000 J/kg. Bulk shear near 50 KT should maintain storm
organization through the afternoon. Effective SRH values are
relatively low but given the CAPE, a few brief spin-ups will be
possible along mesoscale boundaries Sunday afternoon. Locally
heavy rainfall, aided by PWAT near 1.75 inches is also expected,
though storms should remain progressive in movement.

Storm chances south of the I-40 corridor will ramp up Sunday
evening, as additional height falls aid storm development along a
prefrontal outflow boundary. MUCAPE of 2000-3000 J/kg will
support a severe threat into north MS after midnight Sunday night.
Main severe threat will remain damaging wind. Midlevel lapse
rates around 6.5 C/km will support large hail, but the hail threat
will likely be limited by a transition to linear convective mode.
Tornado threat should decrease through late Sunday evening, as
storms become rooted in an elevated layer.

Following the exit of storms over north Mississippi early Monday
morning, a quieter weather pattern will settle in for at least a
couple days. Isolated showers and thunderstorms will be possible
on Memorial Day, mainly near the Tennessee River, but suspect NBM
PoPs may be a bit on the high side Monday afternoon.

Northwest flow aloft will continue through Thursday, with a few
storms possibly dropping through eastern Arkansas and north
Mississippi around midweek.

PWB

&&

.AVIATION...
(12Z TAFS)
Issued at 620 AM CDT Sat May 25 2024

Generally, a decent aviation day is expected. The probabilities
for MVFR cigs this morning have decreased and mostly clear skies
can be found. KJBR does have a tempo for an MVFR deck around
2500ft later this morning.

Diurnally driven thunderstorms are possible this afternoon, as
the HRRR has been hinting at some afternoon development. Tempos
were placed at all TAF sites with the most likely timing. CIGS
with convection should remain above MVFR, but periods of lower
visbys are possible.

Other than the afternoon convection, VFR should prevail until a
cold front moves through late tomorrow afternoon and evening.

AMED NOT SKED at KJBR due to ASOS malfunctions.

DNM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Flood Watch through Monday morning for ARZ009-018-026>028-035-
     036-048-049-058.

MO...Flood Watch through Monday morning for MOZ113-115.

MS...Flood Watch through Monday morning for MSZ001>017-020>024.

TN...Flood Watch through Monday morning for TNZ001>004-019>022-
     048>055-088>092.

&&

$$

PUBLIC FORECAST...PWB
AVIATION...DNM