SEVERE ALERT: Upper Midwest Bracing for Rough Weather, Including Threat for Tornadoes
The Upper Midwest and Great Lakes region have been pummeled by severe storms in recent days and it looks like that trend will continue through the next couple of days.
A strong upper-level low over the Pacific Northwest is helping to create a strong surface low in the northern Plains. This surface low will continue to progress east through the remainder of the day; pumping warm, moist air in to the Dakotas and Minnesota. The associated boundary, a warm front, will be the main focus for convective activity Wednesday afternoon and evening. Outflow boundaries and strong low-level shear will act to enhance storms that develop.
The main threat will be large hail and damaging wind gusts — a few tornadoes can’t be ruled out either. As the evening progresses, the storms will become less discreet (single-cell) and form into a line. Once the storms become more linear, straight-line winds — including the possibility for a bow echo or two — will be the main concern.
Most of the severe activity will be confined to North Dakota and Minnesota, but the far northern part of Wisconsin will be affected as well.
The threat for severe weather continues into Thursday, for the Upper Midwest, as the aforementioned upper-level low tracks along the U.S.-Canada border. The low will be over northern Minnesota by Wednesday afternoon. Convection from Wednesday and a warm layer in the mid-levels of the atmosphere will act to inhibit convective activity for most of the day. But, afternoon late destabilization will aid in the development of some isolated severe storms toward the evening hours.
The main mode of severe weather will be hail and damaging winds. And while tornadoes aren’t expected, they can’t be totally ruled out.
So, if you live in the Arrowhead of Minnesota, the northern two-thirds of Wisconsin and the western part of the U.P. of Michigan, remain weather-aware through the afternoon and evening hours on Thursday.
WeatherNation meteorologists are keeping an eye on the situation and will bring you updates on-air and online.
Meteorologist Alan Raymond