EASTERN NEBRASKA INTO NORTHERN ILLINOIS — A non-zero tornado chance exists across a broad corridor stretching from eastern Nebraska through Iowa and into northern Illinois Friday June 5th, with the threat window running from 5 PM through 10 PM. The Level 1 two percent tornado probability zone covers a large footprint including Omaha, Cedar Rapids, Davenport, and extends eastward toward Chicago and the northern Illinois border.
Any tornadoes that develop are expected to remain below EF-2 intensity, and most guidance suggests storms may not even form. However, enough atmospheric ingredients are present that a brief tornado or two cannot be ruled out.
Low But Non-Zero Tornado Chance Supported by Weak but Sufficient Shear
The tornado setup is characterized by weak but sufficient wind shear to support brief tornado development if a couple of storms manage to fire across the risk corridor. Forecasters are clear that this is a low-probability scenario and most model guidance leans toward limited storm development across the zone.
Despite the low odds, the shear environment is just robust enough that any storm that does organize could briefly produce a tornado before weakening. A chance is a chance regardless of how low the probability sits.
Risk Zone Stretches From Omaha Through Iowa Into Northern Illinois
The green tornado probability zone on the Friday June 5th outlook map covers eastern Nebraska from the Omaha corridor northeastward across the full width of Iowa through Cedar Rapids and Davenport, then extending into northern Illinois approaching the Chicago metro area. Communities across this entire corridor carry the Level 1 two percent tornado probability through the 5 to 10 PM window…