ACUS03 KWNS 240731
SWODY3
SPC AC 240730

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Fri May 24 2024

Valid 261200Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SUNDAY INTO
SUNDAY NIGHT ACROSS PARTS OF SOUTHEASTERN IOWA...EASTERN
MISSOURI...MUCH OF CENTRAL AND SOUTHERN ILLINOIS...MUCH OF CENTRAL
AND SOUTHERN INDIANA...WESTERN AND CENTRAL KENTUCKY...

...SUMMARY...
Severe thunderstorms are likely Sunday into Sunday night across
parts of the middle Mississippi and lower Ohio Valleys.

...Synopsis...
Models indicate that initially low-amplitude mid-level troughing,
comprised of at least a couple smaller-scale perturbations emerging
from the Great Basin and Southwest, will progress northeast and east
of the lower Missouri Valley and central Great Plains during the day
Sunday. It appears that this will be accompanied by notable further
deepening of a relatively compact developing cyclone across the
lower Missouri Valley through the Upper Great Lakes region by late
Sunday night. There may also be a gradual consolidation of
mid-level troughing centered over the Mississippi Valley, within
amplifying flow across the northern mid-latitudes of the eastern
Pacific through North America.

...Southeastern Great Lakes through Ohio Valley/Great Lakes...
Given the large potential instability associated with low-level
moisture return through the warm sector of the developing cyclone,
beneath at least initially capping elevated mixed-layer air, strong
to severe thunderstorm development may accompany mid-level height
falls across a potentially sizable area of the interior U.S. The
details of this evolution remain uncertain, due spread within/among
the model output concerning the synoptic and sub-synoptic
developments, which may include one or two substantial clusters of
convective development across the lower Missouri Valley at the
outset of the period.

At the present time, model output seems suggestive that the most
probable convective evolution may include early period convection
weakening while spreading across and east of the middle Mississippi
Valley during the day. In its wake, a corridor of strengthening
differential surface heating may develop along the western flank of
modifying convective outflow across parts of the lower Ohio Valley northwestward through the middle Mississippi Valley.

By Sunday afternoon, renewed convective development may focus near
the intersection of the outflow and a southward advancing cold front
across the west central Illinois/northeastern Missouri vicinity.
Supported by large mixed-layer CAPE and strong shear, the
environment likely will be conducive to supercells initially, before
low-level warm advection along the remnant outflow supports an
upscale growing cluster which should tend to forward propagate
southeastward across the lower Ohio into Tennessee Valley through
Sunday evening. While convection may gradually increase along the
southward advancing front to the southwest of the outflow boundary,
the outflow boundary/differential heating zone seems likely to
become the focus for the primary severe weather hazards, including a
large hail/supercell tornado risk to damaging winds and perhaps a
continuing QLCS tornado threat.

..Kerr.. 05/24/2024

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