Ann Arbor likely to see 2 storm systems today; derecho possible, forecasters say

This morning's storm system - now making its way into the area - is tracking in the form of a squall line, the weather service said. It should make its way through the region by 1 p.m.

At 11:12 a.m., Doppler radar showed strong thunderstorms along a line east extending from seven miles northeast of Marlette to 33 miles southwest of Adrian, moving east at 45 mph, the weather service said.

The storms so far have the potential for winds greater than 35 mph, occasional ground lightning, and brief heavy downpours, the weather service said.

Forecasters say it's too hard to predict yet whether the later storm - expected to be the more severe of the two - could result in a derecho, a widespread and long lived windstorm associated with a band of rapidly moving showers or thunderstorms.

Meteorologist Amos Dodson of the National Weather Service at White Lake Township said at 6:35 a.m. that a derecho is still possible.

Forecasters are predicting two storm systems in the Ann Arbor area today.

"We haven't been able to nail that down yet," he said. "We'll just have to wait and see."

The second storm system is expected to also bring strong winds, possible hail and heavy rain, Dodson said. The latest estimate as of 10:30 a.m. pegged the time of that storm at between 4 p.m. and 6 p.m.

"Flooding is certainly a possibility because we're expecting heavy rainfall," he said.

In addition to storms, today's forecast calls for dangerously high temperatures. With temps in the low 90s, the heat index could reach 100 degrees in Washtenaw County, officials said.

By 11 a.m., the temperature had reached 76 degrees.