Severe storms with heavy rainfall likely across southern Minnesota Wednesday

A few isolated thunderstorms will drift across southern Minnesota Tuesday evening. There is a marginal (relatively low) risk an isolated storm may reach severe limits with hail or gusty winds Tuesday evening.

But this week’s main weather event arrives Wednesday.

A low-pressure wave will cross southern Minnesota Wednesday. The system will trigger more widespread rain and thunder starting in southwest Minnesota Wednesday morning, then moving eastward across southern Minnesota Wednesday. For the Twin Cities, rain chances will increase rapidly by around midday, with scattered storms likely into Wednesday evening across southern Minnesota.

The Canadian model shows the low and rain waves crossing southern Minnesota Wednesday.

It should be noted that Tuesday’s late afternoon forecast model runs suggest the most concentrated core of storms, and heavier rainfall may trend slightly further south across southern Minnesota on Wednesday.

Here’s NOAA’s GFS 18Z afternoon model rainfall output.

Severe risk Wednesday

The Tuesday afternoon update shows NOAA’s Storm Prediction Center has edged the severe risk zones slightly further south for Wednesday.

The marginal risk zone now includes St. Could. The Twin Cities is now mostly in the slight risk zone. And southern Minnesota and much of Wisconsin are in the enhanced risk zone, with the greatest risk for severe weather featuring damaging wind and possibly large hail.

Heavy rainfall potential

Storms will have plenty of deep moisture to drop heavy rainfall Wednesday. Widespread rainfall totals between 1 and 3 inches look likely.

A few models produce pockets of locally higher totals up to 5 inches in some areas of southern Minnesota.

The bottom line is to be aware of widespread rain and thunderstorms and possible severe weather across the southern half of Minnesota Wednesday.