Mesoscale Discussion 1178
NWS Storm Prediction Center Norman OK
0753 PM CDT Wed Jun 28 2017
Areas affected...Northeast IA...Southern WI...Northern IL
Concerning...Tornado Watch 375...377...378...
Valid 290053Z - 290230Z
The severe weather threat for Tornado Watch 375, 377, 378 continues.
SUMMARY...Severe threat continues.
DISCUSSION...MCS continues to mature as it becomes elongated in an
east-west fashion from northeast IA, east along the WI/IL border.
This complex of storms is sagging south at roughly 15kt with an
eastward surge on the order of 30kt along the leading squall line.
Given this speed/movement, it appears strong convection will
approach the northern Chicago metro between 0200-0230z and around
0200z for the near-lake MI region of southeast WI. As the complex
becomes oriented more east-west there will be a propensity for
training across this region deep into the evening hours.