A tightly cranked up storm system in the Plains tonight with move across the Great Lakes region Monday night and Tuesday. Even though the timing moving through Michigan leans toward escaping major severe weather, NOAA’s severe weather experts still think severe weather is possible.
Here are the forecasts for the three types of severe weather- tornadoes, severe wind gusts and large hail.
Tornado chance within 25 miles of a given point for 8 a.m. Monday to 8 a.m. Tuesday. (Forecast from Storm Prediction Center)
There is a five percent chance of a tornado within about the western half of Lower Michigan and the far eastern part of the U.P. This chance of a tornado officially fits in the time period of 8 a.m. Monday to 8 a.m. Tuesday, October 11-12, 2021. For Michigan the time period most likely to have a tornado or other severe weather is Tuesday 2 a.m. to 8 a.m. The tornado possibility area includes Grand Rapids, Kalamazoo, Battle Creek, Coldwater, Lansing, Midland, Mount Pleasant, Cadillac, Traverse City, Mackinaw City and Sault Ste. Marie.
The area with the chance of damaging severe wind gusts in thunderstorms and one inch hail or larger is the same area as the tornado risk.
Chance of damaging wind gusts for 8 a.m. Monday to 8 a.m. Tuesday.
Large hail chance for 8 a.m. Monday to 8 a.m. Tuesday. (Forecast from Storm Prediction Center)
The Storm Prediction Center gives Michigan the chance of severe weather based on the upper-air dynamics of the storm. We know, however, that time of day is an important factor in creating severe weather. The heat of the afternoon and early evening create the most unstable part of the day. If the storms arrive early in the morning as expected, our severe weather risk could be lower than currently indicated.
In fact, in the Storm Prediction Center’s severe weather discussion they say, “As deep-layer flow becomes more meridional (more south-to-north), convection(thunderstorms) may tend to become undercut by the surging cold front. If this occurs, the severe threat will be somewhat diminished as convection becomes elevated.” Elevated thunderstorms don’t bring severe wind gusts down to the ground.
Looking at one of the best weather models, it looks like a line of severe storms could hit the southwest corner of Michigan around 2 a.m. Tuesday. The storm line would then weaken as it moves east.
It is almost mid-October. It is definitely worth watching and alerting you since severe weather could come as a surprise at this time of year.