Tornado area added to Michigan’s severe storm forecast Friday, includes Ann Arbor, Detroit, Flint, Saginaw, Bay City

The severe weather forecast has been revised for Friday, with one well-defined area emerging as the most likely location for severe thunderstorms and possibly a tornado or two.

We have been tracking a cold front that was supposed to move through Lower Michigan on Friday. That is still the case. The alignment of the cold front in southeast and eastern Lower Michigan during the heat of the afternoon and evening gives us a very good idea of ​​where severe storms are most likely. The oppressive moisture will also return to eastern Lower at the same time, which will contribute to scattered severe storms.

Due to the timing and positioning of the cold front on Friday afternoon, the Storm Prediction Center (SPC) has increased its severe weather forecast for the Saginaw Bay, Thumb, Ann Arbor and Detroit areas.

Here is the brand new, updated weather forecast for Friday afternoon and evening.

The forecast below is for the combined risk of each of three types of extreme weather: high winds, large hail, and tornadoes. The yellow area has the highest risk. The dark green area has a risk one level below the yellow area, and the lowest serious risk that SPC is concerned about.

SPC states that a south-southwest wind that increases during the storm period could produce enough wind shear to rotate into thunderstorms and produce one or two isolated tornadoes. The tornado probability area is the same as the yellow general risk area. Saginaw, Bay City, Midland, Flint, Ann Arbor, Detroit and the entire Thumb have a two to four percent chance of a tornado within 25 miles of any point. What this means realistically is that we could have one or two tornadoes in the highlighted area.

The risk of severe wind gusts is between 15 and 29 percent in the yellow area. Remember that wind gusts from severe thunderstorms only last a few minutes, but can become dangerous very quickly. Keep an eye on the radar so you know if severe storms are coming your way.

The chance of large hail is smaller because it is so warm high in the atmosphere that ice has a harder time forming.

Here is the radar forecast from 9 a.m. Friday through 9 p.m. Friday. The morning thunderstorms over western Lower should weaken as they move into eastern Lower around noon. Then a second line of strong thunderstorms should develop in the Thumb and southeastern Lower Michigan. Note that the line of thunderstorms is not continuous. Some areas will be missed by the thunderstorms. Also, note that the thunderstorms will strengthen in the east and southeast during the late afternoon and evening.

If you plan to work outside or are traveling south from Saginaw/Bay City to Detroit and Ann Arbor on Friday afternoon, be sure to take cover for a half hour as severe thunderstorms are possible.

Stay informed here about any changes to the extreme weather forecast.