Hot, stormy Wednesday brings flood risk, heavy rains to northern and central Minnesota
A severe-warned thunderstorm passes over Terminal 1 at the Minneapolis-St. Paul International Airport on Thursday, May 15, 2025.
Ben Hovland | MPR News
Go Deeper.
Create an account or log in to save stories.
Like this?
Thanks for liking this story! We have added it to a list of your favorite stories.
Audio transcript
NINA MOINI: Our top story. A heat advisory is in effect starting right now, noon, until 8 o'clock this evening for the Twin Cities metro and Southern Minnesota. It's part of a serious heat wave that's hit the state this week, where high humidity is adding to the danger of hot temperatures. Here with me now to explain the forecast for the rest of the week is MPR News chief meteorologist, Paul Huttner. Hi, Paul.
PAUL HUTTNER: Hey, Nina.
NINA MOINI: So we're going to talk about the heat and corn sweat and everything, but we got to talk about severe weather, of course, first. Already seeing some flash flooding it looks like in the Northeastern part of the state, Paul?
PAUL HUTTNER: Yeah, that's exactly right. The radar is busy today across Minnesota, Nina. It was T-Bone Walker that wrote the Stormy Monday Blues. Well, it's a stormy Wednesday in Minnesota. And it's raining hard right now, from the North Shore, Grand Marais, all the way through North Central Minnesota.
We do have several reports of flooding. Albany, flooded streets. Ely, Whiteside park, flooding there on Sheridan street. And then wind damage up around Walker. The Marina has been damaged. There are trees down in the city park. Other reports of trees down in Central Minnesota, Northern Minnesota, and they've had 2 to 5 inches of rain from around that Brainerd Lakes area up through the Iron Range toward the North Shore. So there are flood warnings in effect for much of Central and Northeast Minnesota until about 1:15, 1:45 this afternoon.
Just torrential rains, Nina, with this amount of moisture we have in the air. And it's still raining from Grand Marais down through the Iron Range, down to just South of Duluth now, into Fergus Falls in West Central Minnesota. And then you come south toward the Twin Cities. St. Cloud, garden variety thunderstorms down into the Twin Cities, now west toward Montevideo, Wilmer.
And those storms, with that moisture, they're just dumping heavy rain, rainfall rates of an inch or 2 inches an hour. So that's why that flood watch is out for Northern Minnesota and concern for flooding as we go through the day.
NINA MOINI: Yeah. And we know you'll continue to keep us up to date on anything going on there. This heat wave though, just these temperatures, how hot is it going to be getting?
PAUL HUTTNER: Yeah. We've seen temperatures around 90 the last couple of days. And the real kicker is the dew points because they're up in the 70s, even upper 70s to near 80 degrees. And so that pushes that heat index higher. We've seen heat index values over 100. 102 I saw yesterday down in St. James.
And with those dew points up in the upper 70s to around 80 degrees, that is just tropical Amazon jungle-like moisture. We get that a couple of times a year here in Minnesota and certainly here this week. So that's what will make it uncomfortable.
But I'll say this. We've got these thunderstorms around the Twin Cities now. That may bump our heat down a little bit as the cloud cover keeps us down. But that heat advisory is still in effect from the Twin Cities southward through Albert Lea, Rochester, until 8 o'clock tonight.
NINA MOINI: So all right. Let's talk about corn sweat, Paul. The memes are happening all over the internet. It's the summer of corn sweat, headlines everywhere. Tell us what it is. What's the deal with corn sweat?
PAUL HUTTNER: Yeah, we live-- our landscape, interacts with the atmosphere in Minnesota. And we live in a sea of corn from Southern Minnesota, through all of Iowa and through parts of the Midwest. And those corn plants you see in the field that are getting really tall now, they're over my head here in Carver County in Southwest Twin Cities, they are what we call excellent evapotranspirators.
What that means is they pull moisture from the soil, and they pump it through the plant into the lower atmosphere. And so that can actually turbocharge dew points because it releases that moisture into the air. The Minnesota State Climate Office did a test a few years ago. They've got a corn plot right in St. Paul. And on a calm day, a windless day, they went and took readings right over the corn field and then took readings quite a ways away.
And they found the dew points were up to 5 degrees higher right over that corn field than they were away from the corn field. So think about that and think about if you've driven through Southern Minnesota, where it's just an ocean of corn, well, that's pumping a lot of moisture into the lower atmosphere. The corn is sweating, and it puts that moisture into our atmosphere, makes it feel more humid and also provides more fuel for storms. I mean, the air mass comes from the Gulf of Mexico, so it would be humid anyway. That corn sweat just kind of gives it a boost.
NINA MOINI: Corn sweat. All right. I'm glad I finally what that is because I've been seeing it everywhere. Thank you. What is this weekend and the rest of the week looking like, Paul?
PAUL HUTTNER: Yeah. So here's the good news. All this troubled weather across Minnesota today is with a cool front that's sagging south, and that'll push through here later tonight and tomorrow morning. That'll shut off the rain. Tomorrow looks partly sunny, get to about 84. So more comfortable in the Twin Cities.
86 with sunshine. Friday looks great. Saturday about the same. Little warmer, 88. And then Sunday, we're steamy again. Back into the low 90s with a lot of humidity and some more corn sweat in the air as we head through Sunday, Nina.
NINA MOINI: All right. And give us a sneak peek of Climate Cast this week.
PAUL HUTTNER: Yeah. It's blue green algae. These slimy blue green patches that are showing up in Minnesota lakes, there's an increased amount of this as our water warms in summer, as much as 5 degrees since the 1970s or so. So we'll talk about how to identify that and stay safe for people and pets because it can be dangerous. So blue green algae this week on Climate Cast.
NINA MOINI: Paul, thanks so much.
PAUL HUTTNER: My pleasure. Thanks, Nina.
NINA MOINI: That was MPR News chief meteorologist, Paul Huttner.
PAUL HUTTNER: Hey, Nina.
NINA MOINI: So we're going to talk about the heat and corn sweat and everything, but we got to talk about severe weather, of course, first. Already seeing some flash flooding it looks like in the Northeastern part of the state, Paul?
PAUL HUTTNER: Yeah, that's exactly right. The radar is busy today across Minnesota, Nina. It was T-Bone Walker that wrote the Stormy Monday Blues. Well, it's a stormy Wednesday in Minnesota. And it's raining hard right now, from the North Shore, Grand Marais, all the way through North Central Minnesota.
We do have several reports of flooding. Albany, flooded streets. Ely, Whiteside park, flooding there on Sheridan street. And then wind damage up around Walker. The Marina has been damaged. There are trees down in the city park. Other reports of trees down in Central Minnesota, Northern Minnesota, and they've had 2 to 5 inches of rain from around that Brainerd Lakes area up through the Iron Range toward the North Shore. So there are flood warnings in effect for much of Central and Northeast Minnesota until about 1:15, 1:45 this afternoon.
Just torrential rains, Nina, with this amount of moisture we have in the air. And it's still raining from Grand Marais down through the Iron Range, down to just South of Duluth now, into Fergus Falls in West Central Minnesota. And then you come south toward the Twin Cities. St. Cloud, garden variety thunderstorms down into the Twin Cities, now west toward Montevideo, Wilmer.
And those storms, with that moisture, they're just dumping heavy rain, rainfall rates of an inch or 2 inches an hour. So that's why that flood watch is out for Northern Minnesota and concern for flooding as we go through the day.
NINA MOINI: Yeah. And we know you'll continue to keep us up to date on anything going on there. This heat wave though, just these temperatures, how hot is it going to be getting?
PAUL HUTTNER: Yeah. We've seen temperatures around 90 the last couple of days. And the real kicker is the dew points because they're up in the 70s, even upper 70s to near 80 degrees. And so that pushes that heat index higher. We've seen heat index values over 100. 102 I saw yesterday down in St. James.
And with those dew points up in the upper 70s to around 80 degrees, that is just tropical Amazon jungle-like moisture. We get that a couple of times a year here in Minnesota and certainly here this week. So that's what will make it uncomfortable.
But I'll say this. We've got these thunderstorms around the Twin Cities now. That may bump our heat down a little bit as the cloud cover keeps us down. But that heat advisory is still in effect from the Twin Cities southward through Albert Lea, Rochester, until 8 o'clock tonight.
NINA MOINI: So all right. Let's talk about corn sweat, Paul. The memes are happening all over the internet. It's the summer of corn sweat, headlines everywhere. Tell us what it is. What's the deal with corn sweat?
PAUL HUTTNER: Yeah, we live-- our landscape, interacts with the atmosphere in Minnesota. And we live in a sea of corn from Southern Minnesota, through all of Iowa and through parts of the Midwest. And those corn plants you see in the field that are getting really tall now, they're over my head here in Carver County in Southwest Twin Cities, they are what we call excellent evapotranspirators.
What that means is they pull moisture from the soil, and they pump it through the plant into the lower atmosphere. And so that can actually turbocharge dew points because it releases that moisture into the air. The Minnesota State Climate Office did a test a few years ago. They've got a corn plot right in St. Paul. And on a calm day, a windless day, they went and took readings right over the corn field and then took readings quite a ways away.
And they found the dew points were up to 5 degrees higher right over that corn field than they were away from the corn field. So think about that and think about if you've driven through Southern Minnesota, where it's just an ocean of corn, well, that's pumping a lot of moisture into the lower atmosphere. The corn is sweating, and it puts that moisture into our atmosphere, makes it feel more humid and also provides more fuel for storms. I mean, the air mass comes from the Gulf of Mexico, so it would be humid anyway. That corn sweat just kind of gives it a boost.
NINA MOINI: Corn sweat. All right. I'm glad I finally what that is because I've been seeing it everywhere. Thank you. What is this weekend and the rest of the week looking like, Paul?
PAUL HUTTNER: Yeah. So here's the good news. All this troubled weather across Minnesota today is with a cool front that's sagging south, and that'll push through here later tonight and tomorrow morning. That'll shut off the rain. Tomorrow looks partly sunny, get to about 84. So more comfortable in the Twin Cities.
86 with sunshine. Friday looks great. Saturday about the same. Little warmer, 88. And then Sunday, we're steamy again. Back into the low 90s with a lot of humidity and some more corn sweat in the air as we head through Sunday, Nina.
NINA MOINI: All right. And give us a sneak peek of Climate Cast this week.
PAUL HUTTNER: Yeah. It's blue green algae. These slimy blue green patches that are showing up in Minnesota lakes, there's an increased amount of this as our water warms in summer, as much as 5 degrees since the 1970s or so. So we'll talk about how to identify that and stay safe for people and pets because it can be dangerous. So blue green algae this week on Climate Cast.
NINA MOINI: Paul, thanks so much.
PAUL HUTTNER: My pleasure. Thanks, Nina.
NINA MOINI: That was MPR News chief meteorologist, Paul Huttner.
Download transcript (PDF)
Transcription services provided by 3Play Media.