600 
ACUS01 KWNS 230058
SWODY1
SPC AC 230056

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0756 PM CDT Thu Oct 22 2020

Valid 230100Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A PORTION
OF THE MIDWEST AS WELL AS THE SOUTHERN PLAINS...

...SUMMARY...
A few strong storms with mostly a threat for marginally severe hail
are possible this evening, mainly from eastern Iowa into northwest
Illinois and southern Wisconsin. Other storms capable of marginally
severe hail may occur later tonight across a portion of southeast
Oklahoma into north central Texas.

...Midwest through a portion of the upper Great Lakes...

Have downgraded to MRGL category this update. The severe weather
parameter space is conditionally favorable for severe storms in warm
sector, with strong vertical shear profiles and large low-level
hodographs along with moderate instability based on the 00Z RAOB
from Davenport IA. However, with modest inversion present near 700
mb and a stabilizing surface layer, it appears forcing will remain
insufficient to initiate storms away from the cold front which
currently extends from eastern IA southwestward through eastern KS.
Numerous storms will continue developing this evening primarily in
post-cold frontal region as well as north of a warm front across WI.
These storms will be elevated, but sufficient instability and lapse
rates exist for at least a marginal hail threat with the stronger
storms. 

...Southeast Oklahoma through north central Texas...

Evening RAOB data show a capped atmosphere across OK into north
central TX with steep lapse rates above a moist boundary layer.
Satellite imagery indicates a shortwave trough located across
western TX and forcing for ascent accompanying this feature will
interact with a southward surging cold front across this region
later tonight, likely resulting in the development of thunderstorms.
While vertical shear will remain weak and supportive of multicells
along the front, steep lapse rates and moderate instability suggest
a few of the stronger storms could produce marginally severe hail.

..Dial.. 10/23/2020

$$