813
FXUS64 KMEG 252352
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
652 PM CDT Sat May 25 2024

...New AVIATION...

.SYNOPSIS...
Issued at 342 PM CDT Sat May 25 2024

Enhanced severe weather chances return Sunday with multiple
rounds of storms possible through early Monday morning. The main
concern at this time remains potential for afternoon supercells to
develop and produce all hazards of severe weather. In addition,
flooding chances remain elevated as efficient rainfall rates
accompany storms. Unsettled weather should come to an end on
Monday, when dry conditions return to the Mid-South.

&&

.DISCUSSION...
(This evening through next Friday)
Issued at 342 PM CDT Sat May 25 2024

Shortwave ridging aloft has precluded shower and thunderstorm
chances this afternoon, with only a few pop-up storms present on
radar as of 3PM. Isolated storms may continue to develop over the
next few hours, with a few possibly reaching severe limits. If
storms do form, the main concerns will be damaging winds and large
hail.

Greater severe weather chances will materialize on Sunday, with
multiple rounds of storms possible. The first round will be driven
by a shortwave trough pushing into the Midwest late tonight.
Several CAMs depict an MCS developing over Missouri, pushing
eastward into Kentucky by 7AM. The main question regarding this
round of storms lies in the southern extent of the MCS. The 18Z
HRRR keeps storms along the Kentucky / Tennessee border. However,
all other CAMs support storms pushing well into northeast Arkansas
and the Missouri Bootheel. Regardless of which scenario
materializes, severe weather chances will be possible as dewpoints
surge to the low 70s by 7AM. The main threats with this batch of
storms will be damaging winds and large hail.

A secondary round of convection may materialize in the mid
afternoon hours along a remnant outflow boundary from the
aforementioned MCS. At this time, hodographs become more favorable
for tornadic development with 0-3 km SRH increasing to 250 m2/s2
in portions of northwest Tennessee. In addition, mid-level lapse
rates on the order of 7.5 C/km will support strong updrafts
capable of producing large hail. Any storms that develop at this
time will likely be discrete and pose the greatest tornadic
threat, with a few significant tornadoes possible. As such, the
Storm Prediction Center has extended portions of the Enhanced Risk
to areas of northwest Tennessee. Important note: confidence for
this round of storms remains low due to uncertainties in exact
track of Sunday morning`s MCS. The bottom line: if storms do form
in the afternoon, they will be capable of all hazards.

A third, and final round of storms will occur late Sunday evening
into the overnight hours. Convection is expected to form along a
cold front that pushes southeast across Missouri in the evening
hours. By the time this line impacts the Mid-South, a QLCS
structure will be evident with damaging winds the primary concern.
A few CAMs decrease lapse rates to around 5.5 - 6.0 C/km
overnight, which should hamper large hail development. However,
brief spin-up tornadoes will remain possible as the LLJ
strengthens and SRH values remain around 150 - 200 m2/s2. The main
areas of concern for this round of storms will be northeast
Arkansas and west Tennessee. By 4AM Sunday, the severe weather
threat will wane with dry conditions returning Monday.

In addition to severe weather concerns, flooding potential remains
elevated as precipitable water values approach the 99th
percentile. Any storms that do develop will likely be prolific
rainfall producers, resulting in rises of rivers and streams. The
Flood Watch has been adjusted to include areas north of the
Tennessee / Mississippi state border now through 7AM Monday.
Additional rainfall totals of 1-2 inches with locally higher
amounts are possible.

ANS

&&

.AVIATION...
(00Z TAFS)
Issued at 650 PM CDT Sat May 25 2024

Main story this TAF issuance is the timing and intensity of TSRA
across each terminal tomorrow afternoon and into the overnight
hours. Latest CAMs have two lines of convection: the first looks
to form along a few shortwaves out ahead of the second main line
associated with a cold front. TSRA is expected to begin impacting
JBR/MEM/MKL beginning around 21Z tomorrow afternoon through the
TAF period as these lines of convection move across the Mid-South.
South/southwest look to gust up to 30 kts tomorrow morning
through the TAF period as this cold front passes. VFR conditions
are expected to prevail, though each terminal could see a brief
lowering to MVFR with onset convection.

AEH

&&

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

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

MS...None.
TN...Flood Watch through Monday morning for TNZ001>004-019>022-
     048>055-088>092.

&&

$$

PUBLIC FORECAST...ANS
AVIATION...AEH