756
ACUS01 KWNS 130600
SWODY1
SPC AC 130558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Thu Jun 13 2024

Valid 131200Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR EXTREME
NORTHEAST KS INTO NORTHERN MO...SOUTHERN IA...WESTERN/NORTHERN IL...

...SUMMARY...
Severe thunderstorms are most likely across southern Iowa into
northern portions of Missouri and Illinois during the late afternoon
to early evening. Very large hail, destructive wind gusts, and a
couple tornadoes are possible.

...Central Great Plains to the central Great Lakes...
An active severe-weather episode still appears possible this
afternoon and evening, centered across parts of the Midwest. Very
large hail (potentially baseball-size or larger), severe wind gusts
in excess of 75 mph, and a couple tornadoes will all be possible.
The Enhanced Risk has been expanded slightly southward based on the
latest guidance.

A seasonably strong mid/upper-level shortwave trough and attendant
jet maximum will move across parts of the upper Midwest and Great
Lakes today. A surface low will deepen as it moves across parts of
Ontario and Quebec, with a trailing cold front expected to move
across parts of the central Great Plains, Midwest, and Great Lakes.
A secondary low may develop along the front across parts of central
KS during the afternoon.

Steep midlevel lapse rates, strong heating, and relatively rich
low-level moisture will support strong to locally extreme buoyancy
near and south of the front this afternoon into the evening.
Moderate midlevel west-northwesterly flow will impinge upon the warm
sector from northern MO/southern IA into the Great Lakes, supporting
sufficient effective shear for storm organization, including the
potential for supercells. Deep-layer flow/shear will be weaker with
southwestward extent across the central Great Plains, but still
modestly supportive of a few stronger storms.

There will be some potential for morning convection to intensify as
it moves eastward across parts of WI/MI through the day, with an
attendant threat of isolated damaging wind gusts and hail. Farther
southwest along the front, supercell development will be possible by
mid/late afternoon from southern/eastern IA into northern MO and
northern IL, with an initial threat of very large hail and localized
severe gusts. While low-level flow/shear will not be particularly
strong, a couple of tornadoes will also be possible, given the
potential for a few intense supercells within a strongly unstable
environment. Upscale growth into one or more clusters will be
possible by early evening, with increasing potential for severe
gusts in excess of 75 mph. The severe threat should gradually wane
after dusk, due to increasing MLCINH with time and southeastward
extent.

...CO Front Range into parts of the central/southern High Plains...
Isolated strong to severe storm development is possible this
afternoon and evening from parts of the CO Front Range into
northeast CO, primarily within a post-frontal regime. Any such
development could pose a threat of localized hail and severe gusts.
Farther south, isolated to scattered high-based storm development
will be possible within a hot and well-mixed environment from
western/central KS into northwest OK and the TX/OK Panhandle. Severe
gusts will be possible with the strongest storms within this regime,
along with some potential for isolated hail.

..Dean/Weinman.. 06/13/2024

$$