Thunderstorm chance increases overnight

Thunderstorms are developing near a cold front in the Dakotas this Sunday evening. They will spread eastward overnight, aided by an upper level disturbance.

The National Weather Service North American Mesoscale forecast model shows thunderstorms spreading across Minnesota overnight into early Monday morning:

There appears to be a break in the shower/thunderstorm activity from late morning through about mid-afternoon on Labor Day, then more development Monday evening and Monday night.

Severe weather

The Storm Prediction Center of the National Weather Service shows a slight risk of severe weather over a small part of west-central and northwestern Minnesota overnight into very early Monday:

There is a marginal risk of severe weather over parts of southwestern, northwestern and central Minnesota.

Here are the risk categories that are used by the Storm Prediction Center:

For Monday and Monday night, the slight risk of severe weather expands to cover much of Minnesota, including the northwestern portion of Twin Cities metro area:

You can follow severe weather developments on the MPR News live blog.

Significant rain possible 

Some spots could see heavy rain late tonight and early Monday morning. The cold front that moves through Minnesota late Monday will stall out, becoming a stationary front. That could lead to additional periods of heavy rain Monday night through Wednesday over parts of southern and central Minnesota and western Wisconsin.

Here is a summary of possible rainfall totals from Monday through Wednesday, courtesy of the NWS Twin Cities office:

Exact thunderstorm rainfall totals are very difficult to predict, and some spots could have much higher three day totals if they receive more thunderstorms.

Drier weather is expected on Thursday, then the chance of thunderstorms returns on Friday.