SPC AC 190540
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Tue Oct 19 2021
Valid 201200Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF THE MIDWEST...
A few strong storms with gusty winds and hail will be possible over
a portion of the Midwest region on Wednesday.
A shortwave trough now situated over the Great Basin will advance
east, reaching the Midwest on Wednesday. The accompanying cold front
will extend from a surface low in northwest IA southwest through the
central Plains by 12Z Wednesday. A warm front will stretch eastward
from the low into the Great Lakes. By the end of the period the cold
front should extend from a surface low near Lake MI southwest into
southern IL and the southern Plains. Partially modified Gulf air
with a narrow corridor of mid 50s to near 60 F dewpoints will return
through the warm sector resulting in 500-1000 J/kg MUCAPE. Showers
and thunderstorms will likely be in progress early Wednesday within
zone of stronger forcing north of the warm front from northern IA
into southern MN. Given steep 700-500 mb lapse rates and up to 1000
J/kg MUCAPE, some hail will be possible with the stronger storms.
Later in the day, additional thunderstorm development is possible
farther southeast from IL into eastern MO within corridor of ascent
along and just ahead of the cold front. This activity will be
embedded within moderate to strong deep layer winds and 40-45 kt
effective bulk shear. It appears that the updraft inflow layer will
be rooted above the surface, but sufficient dry air may be present
in the boundary layer to support at least a marginal risk for a few
strong to damaging wind gusts.
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z