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412
FXUS64 KMEG 210803
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
303 AM CDT Tue May 21 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
-- Changed Discussion --
Issued at 302 AM CDT Tue May 21 2024

An unsettled weather pattern kicks off tonight as several systems
will cross the Mid-South. Wednesday night into Thursday is currently
the highest chance of severe weather. Temperatures will continue to
be near to above normal through the forecast period. Rain chances
are highest along and north of Interstate 40 with forecast
precipitation amounts of 4 to 6 inches over the next 7 days.
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&&

.DISCUSSION...
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(Today through Monday)
Issued at 302 AM CDT Tue May 21 2024

High pressure will continue to be pushed east by a complex of
thunderstorms as a low pressure system ejects from the four corners
region. An MCS is likely to decay as a very dry air is depicted
aloft on water vapor satellite imagery. A Marginal Risk is in effect
tonight for northeast Arkansas and a portion of the Missouri
Bootheel.  If a bowing segment is able to materialize, the forecast
environment may possess around 40kts of 0-6km bulk shear for a
damaging wind threat. As the cluster decays, it will be a race
against time due to diurnal stability trends. Confidence is low in
severe weather materializing, but a few storms could bring some
gusty winds and maybe small hail.

Tonight kicks off an unsettled weather pattern. NBM Thunderstorm
probabilities hang around the 30-60% range beginning Wednesday
afternoon through Monday. The attention does shift to Wednesday
afternoon into evening where an Enhanced Risk for severe weather has
been introduced. Southwesterly flow will surge a moisture plume and
bring dewpoints into the 70s ahead of a strong cold front.
Deterministic soundings are indicative of a damaging wind and large
hail as the primary threats. Inverted V soundings will provide
excellent mixing with around 50kts of effective shear. Unstable
lapse rates (~7 C/km) through the column with MLCAPE ~2500 J/kg may
bring large, to very large hail mainly to northeast Arkansas and the
Missouri Bootheel. On a positive note, 0-1km and 0-3km SRH values
are low which keeps the tornadic threat low compared to the wind
and hail threats. PWs are hanging in the 90th percentile or
higher, meaning locally heavy rainfall is possible. Particularly
with any strong updrafts could lead to localized flooding. Current
QPF values are highest along and north of I-40. A Flood Watch may
be needed if QPF continues to trend upward.

While it will not rain or thunderstorm the entire forecast period
(some areas may have breaks), another cluster of thunderstorms will
move through Thursday night into Friday. Several series of
systems continue to cross each night until dry conditions return
Tuesday evening. This active pattern is a result of the a heat
dome over Mexico making the Mid-South and adjacent areas
susceptible to an active weather pattern. QPF for the next 7 days
range from 4-6" along and north of I-40 and areas like Aberdeen,
MS may only see an inch. We will keep an eye on this active
weather pattern and monitor any severe potential in the coming
days.

DNM
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&&

.AVIATION...
(00Z TAFS)
Issued at 612 PM CDT Mon May 20 2024

VFR conditions will persist over the next 30 hours. A deepening
surface low will move across the Middle Mississippi Valley early
tomorrow and tighten the pressure gradient across the region. Wind
gusts will likely exceed 20 knots at all sites.

AC3

&&

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

$$

PUBLIC FORECAST...DNM
AVIATION...AC3