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699 
ACUS01 KWNS 201610
SWODY1
SPC AC 201609

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1109 AM CDT Thu Sep 20 2018

Valid 201630Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN
IOWA TO SOUTHERN MINNESOTA AND WESTERN WISCONSIN...

...SUMMARY...
Severe thunderstorms over parts of the Upper Midwest this afternoon
and evening should produce damaging wind gusts, tornadoes and
sporadic large hail.

...Upper Midwest...
Only minor changes have been made to the ongoing forecast today. 
Morning visible satellite imagery and surface analysis show the
primary warm front extending across central IA.  This boundary will
develop/move northward through the day and into parts of MN/WI by
this evening.  Intense low-level shear profiles will develop along
and north of the boundary, resulting in significant conditional
potential for supercells and associated tornadoes.  However, 12z CAM
solutions show very limited discrete convective development in this
region prior to the approach of a severe squall line this evening. 
Nevertheless, will maintain the ongoing tornado risk probabilities
due to conditional concerns, and due to potential for
QLCS-associated tornado threat this evening.

By late afternoon, an intense squall line will develop along the
cold front sweeping into eastern NE, western IA and southwest MN. 
Strong wind fields, ample instability, and significant large-scale
forcing all support the risk of rather widespread damaging winds
with the storms.  The activity should spread quickly eastward across
the ENH risk area through mid-evening.  Damaging wind gusts are the
main threat, but hail and a few tornadoes will also be possible -
especially near the synoptic low track over southeast MN and western
WI.

..Hart/Coniglio.. 09/20/2018

$$