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000
FXUS64 KMEG 180217
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
917 PM CDT Wed Apr 17 2024

...New UPDATE...

.UPDATE...
Issued at 902 PM CDT Wed Apr 17 2024

Skies are mostly clear across the Mid-South this evening with
temperatures in the mid 60s to mid 70s. Currently, low pressure
was centered over southeast Colorado.

South winds will bring clouds into the region overnight which will
last into Thursday morning. The low will track east on Thursday
and drag a cold front into western Arkansas by Thursday night.
Showers and thunderstorms are expected to develop ahead of the
front with this activity moving into western sections of the Mid-
South by late Thursday afternoon. As the cold front moves into the
region Thursday night, more thunderstorms are expected. Some of
the thunderstorms could be severe mainly over northern sections of
the Mid-South with damaging winds as the main threat. Will update
forecast to remove evening wording.

ARS

&&

.SYNOPSIS...
Issued at 320 PM CDT Wed Apr 17 2024

Thunderstorms will return to the Midsouth on Thursday afternoon
and evening, ahead of a deep low pressure system lifting into the
mid-Mississippi River Valley. Scattered severe thunderstorms will
be possible, especially over northeast Arkansas, the Missouri
bootheel and West Tennessee. Damaging winds will be primary
threat, while secondary threats include large hail and short-lived
tornadoes.

Showers and thunderstorms will continue Friday and Saturday, with
limited severe chances. Dry conditions will settle in Sunday
afternoon and evening, followed by much cooler temperatures
Monday and Tuesday.

&&

.DISCUSSION...
(This evening through next Tuesday)
Issued at 320 PM CDT Wed Apr 17 2024

A deep closed upper low will lift east across the southern
Canadian prairie through late Thursday. A shortwave trough will
round the base of this upper low, tracking from central plains
into the mid-Mississippi River Valley Thursday afternoon.
Midlevel height falls and an associated surface cold front will
move into the Midsouth Thursday night. Several CAMs depict a
frontal wave over southeast MO, which may back winds sufficiently
for a modest bump in the tornado threat over far northeast AR and
the MO bootheel early Thursday evening. Today`s 12Z HREF mixed-
layer mean average CAPE is depicted around 1500 J/kg at 00Z/7PM
CDT Thursday, down from as high as 2300 J/kg earlier Thursday
afternoon. 0-6km bulk shear should prevail at an adequate
35-40kt.

Confidence on Thursday`s severe weather magnitude is limited by
timing questions and a stabilizing boundary layer during the
evening. Sufficient elevated instability will be available above
the forming inversion for a severe wind threat, especially if a
cold pool can organize upstream over southern MO during the
afternoon. Downstream of this forcing, midlevel lapse rates will
be very steep, near 8C/km in an elevated mixed layer (EML). With
mixed layer CAPE in excess of 2000 J/kg, this would be supportive
of very large hail. But the EML will most likely serve to cap
surface-based discrete convection in the afternoon. If the cold
pool were to arrive faster than the CAMs indicate, the severe
wind, hail and tornado threat would be enhanced relative to the
expected evening arrival.

The remnant outflow/residual frontal boundary will settle across
north MS on Friday, though low amplitude ridging should suppress
most thunderstorm development.

Elevated moisture will return north on Saturday, in advance of an
an open upper level trough moving into the central MS River
Valley. NBM thunder chances appear a bit overdone on Saturday,
even considering modest elevated instability. Surface temps will
prevail on the cool side, with most of the Midsouth in the lower
to mid 60s on Saturday.

Cool and less humid conditions will settle in late Sunday and
Monday, following the exit of the midlevel trough and reinforcing
surface cold front.

PWB

&&

.AVIATION...
(00Z TAFS)
Issued at 555 PM CDT Wed Apr 17 2024

VFR conditions expected for the start of the period. However,
probabilistic guidance suggests a good potential for the
development of MVFR stratus developing at MEM after 10Z...and IFR
conditions at remaining sites. Low clouds expected to dissipate
by 15Z with VFR conditions returning. S winds will increase on
Thursday. At this time it appears the best potential for TSRA
will be Thursday night and may need to include in 06Z TAF set.

&&

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

$$

PUBLIC FORECAST...PWB
AVIATION...CJC