644
ACUS02 KWNS 250500
SWODY2
SPC AC 250459

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1159 PM CDT Fri May 24 2024

Valid 261200Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SUNDAY
AFTERNOON INTO SUNDAY EVENING ACROSS MUCH OF EASTERN
MISSOURI...CENTRAL AND SOUTHERN ILLINOIS...CENTRAL AND SOUTHERN
INDIANA...MUCH OF KENTUCKY AND ADJACENT NORTHERN TENNESSEE...

...SUMMARY...
Widespread strong to severe thunderstorm development appears
possible across parts of the southeastern Great Plains and lower
Missouri Valley into the Ohio and Tennessee Valleys Sunday afternoon
through Sunday night.  It is possible this could include the
evolution of at least one large, long-lived organized cluster of
storms posing a risk for damaging wind gusts, from parts of east
central Missouri and west central Illinois through much of Kentucky
and adjacent portions of northern Tennessee.

...Synopsis...
Models indicate that initially low-amplitude mid-level troughing,
comprised of at least a couple of smaller-scale perturbations
emerging from the Great Basin and Southwest, may undergo substantive
amplification while slowly progressing northeast and east of the
lower Missouri Valley and central Great Plains during this period.
The lead embedded perturbation may 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.  To the southwest of this cyclone, a cold front is
forecast to surge southward through much of Missouri, northwestern
Arkansas and the southern Great Plains Red River Valley.

It appears that the front will be preceded by a sharpening dryline
near the Kansas/Missouri border area southwestward through central
Texas by late afternoon, while a plume of warm elevated mixed-layer
air continues advecting east of the southeastern Great Plains
through much of the mid/lower Mississippi Valley and lower Ohio
Valley through southern Appalachians.  Beneath this regime,
moderately strong southwesterly low-level flow will contribute to
low-level moisture return across the Mississippi Valley through the
lower Great Lakes and Appalachians, but this may be complicated by
the influence of remnant convection and convective outflow from
areas upstream late Saturday through Saturday night.

...Southeastern Great Plains through Ohio Valley/Great Lakes...
Latest model output, including convection allowing guidance,
suggests that several remnant convective clusters may be ongoing at
12Z Sunday across parts of the lower Missouri/middle Mississippi
Valley vicinity.  It is possible that destabilizing moist low-level
inflow to the south and southwest of the southern-most activity may
be sufficient to maintain or support re-intensification of
convection east-southeastward through parts of the lower
Ohio/Tennessee Valleys during the day.  If this occurs, beneath a
seasonably strong west-southwesterly mid/upper jet, vertical shear
may contribute to an organizing system capable of producing
sustained damaging wind gusts.

Otherwise, a perhaps more prominent signal persists in model output
that a corridor of strengthening differential surface heating, near
the western flank of modifying convective outflow and beneath the
leading edge of the plume of warm and capping elevated mixed-layer
air, may become a focus for renewed convective develop by Sunday
afternoon.  Initially in a corridor roughly across northeast/east
central Missouri into west central Illinois, lift associated with
warm advection and inflow of boundary-layer air characterized by
CAPE in excess of 3000 J/kg may contribute to upscale growing
convective development, with potential to organize into a
southeastward propagating convective system.  Given seasonably high
boundary-layer moisture content beneath dry mid-levels with very
steep lapse rates, a strong cold pool may eventually evolve and pose
a risk for sustained damaging wind gusts across parts of the lower
Ohio and Tennessee Valleys through Sunday evening.

..Kerr.. 05/25/2024

$$