375
ACUS01 KWNS 131217
SWODY1
SPC AC 131215

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0715 AM CDT Thu Jun 13 2024

Valid 131300Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER PORTIONS OF NORTHERN MISSOURI...SOUTHERN IOWA...AND
NORTHERN ILLINOIS...

...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.

...Great Lakes...
Morning water vapor imagery shows a progressive shortwave trough
over the Dakotas, with an associated cluster of showers and
thunderstorms over eastern SD.  This feature will track eastward
through the day, with large scale forcing for ascent overspreading
parts of southern WI/northern IL and Lower MI by early afternoon.
Strong daytime heating in this area will likely result in
intensification of thunderstorms along an approaching cold front, in
an environment of steep low and mid level lapse rates and moderate
CAPE.  Activity will spread across Lake Michigan and southern Lower
MI through early evening with a risk of hail and damaging winds.

...Middle MS Valley...
The aforementioned surface cold front will extend southwestward
across southern IA and into northeast KS by mid afternoon.  Strong
daytime heating will yield afternoon temperatures in the upper 80s
to mid 90s ahead of the front, along with a corridor of dewpoints in
the mid-upper 60s.  Forecast soundings in this zone show large
MLCAPE values over 3000 J/kg along with steep low and mid level
lapse rates.  Convective initiation along the front may be delayed
until late afternoon or early evening due to warm temperatures in
the 800-700mb layer, but eventually discrete supercells are expected
to form along the front.  Storms will track east-southeastward
across the ENH risk area posing a risk of very large hail, damaging
winds, and perhaps a tornado or two.  Upscale organization into one
or more bowing structures is also expected this evening with an
increased risk of damaging winds.

...Western KS to TX Panhandle...
A hot and deeply mixed boundary layer will develop this afternoon
from the northeast TX Panhandle into western KS, with temperatures
over 100F.  Most CAM solutions suggest scattered coverage of
high-based thunderstorms in this region.  Forecast soundings show
inverted-v profiles, but also sufficient winds aloft to pose a risk
of locally damaging wind gusts for a few hours during the evening.

..Hart/Bentley.. 06/13/2024

$$