Huttner: Warmer weather in store for Minnesota

CATHY: Minnesotans are a funny bunch. Many of us bellyache about the extended snow and cold of our winters. And then when there's the first big burst of summery steam heat, it's too hot.

Indeed, it was hot enough for a lot of people yesterday as temperatures were well into the 90s in southern Minnesota. The Twin Cities hit 96. And that's just the appetizer. Today's a little palate cleanser before a sweltering mass of hot air settles in this weekend.

Let's check in right now with MPR chief meteorologist Paul Huttner. Hey, Paul. How are you?

PAUL: Hey. I'm great, Cathy. And that 96 yesterday, by the way, our third 90 degree day of the year so far in the Twin Cities. The average for the whole summer is 13.

CATHY: Oh, OK. That's not a great thing I guess.

PAUL: We have a ways to go.

CATHY: We do, yeah. Hey, can we talk a little bit about this severe risk here this afternoon?

PAUL: Yeah, and it's setting up mainly south and east of the Twin Cities. NOAA's Storm Prediction Center issues these updates for what we call a convective outlook a few times a day.

Just sent another one. They do that around 12:30 every day. So they upgraded to a moderate risk, which is the second highest level, for parts of Wisconsin, basically Sparta, Wisconsin Rapids, Baraboo, Toma, down to Mattison. Folks are familiar with that drive down I-94.

And then enhanced risk, which is the next level down, Decorah, Iowa, up through far southeast Minnesota. And then a slight risk, a little less, Eau Claire, Rochester, Austin. And then Twin Cities, just basically the eastern half, in the marginal risk. That's the lowest risk for severe weather.

Here's what's going on right now, and what's going to happen today. We've got some scattered showers and a few thundershowers, just garden variety, basically northwest Twin Cities. Showers from North Brach down to Cambridge, Elk River back toward Glencoe.

Then a few scattered thundershowers from St Peter through New Prague up through Jordan into the eastern Twin Cities. Pretty good little cell. Oakdale, Stillwater, right now up toward New Richmond. That's maybe got some small hail with it, dumping some heavy rain, some lightning and thunder.

And then most of the stronger storms, Cathy, are in southeast Minnesota, just east of Rochester into Wisconsin. That's the area where NOAA's Storm Prediction Center is likely going to issue a severe weather watch here, probably in the next couple of hours, for southeast Minnesota into western Wisconsin.

So Twin Cities, a few showers, a thunderstorm, maybe some small hail. I do not think we have a big severe risk. But Rochester, Decorah, over into Wisconsin, you could see some strong to severe storms today.

CATHY: OK. Well, of course, we'll keep up to date on that. It looks like today, as I mentioned, kind of a relief from yesterday. How much cooler and less humid will it be through Friday?

PAUL: Well, we're going to get about three days of relief. So today we're mainly in the 70s. Tomorrow and Friday look glorious, low 80s for highs in the Twin Cities, comfortable dew points in the 50s.

And Saturday looks pretty nice, too, 85 with partly cloudy skies. You'll notice the humidity coming up. But Sunday, Monday, the heat is back. We're back into the 90s, 92 to 96, again. Dew points around 70.

So we've got Wurzer weather in spades coming again Sunday and Monday. I think we'll see day four and five of 90 degree heat Sunday and Monday.

CATHY: How's it look, long range, into the rest of the week?

PAUL: It looks like mostly 80s next week. So I don't think the intense heat is going to stick around.

CATHY: OK. Hey, Rainy Lake. Our friends on Rainy Lake have just really had a tough, tough spring. But some good news that the lake level is falling?

PAUL: It is. I'm watching the gauge there, the inflow and outflow. And the inflow is down to about 50,000 cubic feet per second. That's a lot. But the outflow is 53,000.

So that lake has leveled off. It's still in record flood territory, but its level to falling slightly. They got a shot of rain up there last night. But the forecast looks drier over the next week. So I think we're going to see that lake start to fall, gradually, here over the next week.

CATHY: Say, can I ask you something about-- This goes back to severe weather. Earlier this morning, Cliff Bentley, who I know you know. He's our great technical director. Cliff was coming in to work, and he said, wow. It was just really a great display of lightning earlier this morning as he was coming in.

Can I ask you, there is a Lightning Detection Network. Right? Is there a Minnesota connection to that?

PAUL: There is. In fact, that National Lightning Detection Network has over 100 sensors around the country. A company called Vizsla in Tucson-- I've actually visited there and interviewed people-- runs that. But it does have a Twin Cities connection.

That technology was partially developed in the 80s here in the Twin Cities. Do you remember Dr. Walt Lyons--

CATHY: Yes.

PAUL: who used to work at KSTP and WCCO? Well that was actually my first real job in weather. I worked for Dr. Walt during college. And he had developed this technique for tracking lightning strikes, one of a few people working on this.

So that got rolled into this National Lightning Detection Network. And Minnesota gets about 3 and 1/2 million lightning strikes a year, on average. It varies quite a bit from year to year. So we have a lot of it.

And I actually geeked out a little here. And I want to turn this up. I don't know if you can hear this. But we'll see if we can catch some lightning strikes.

[TICKING]

If you hear those little tics, that is actual real-time, cloud to ground lightning. Those strikes you just heard were around Eau Claire. There are storms in Wisconsin. There's even a few down around St Peter.

So you can track it with pinpoint precision, Cathy. It's called time of arrival. The lightning strikes send out a spheric and electromagnetic pulse that's sensed by the sensors. And then they calculate it, three or more of them, to pinpoint that strike really within a few yards.

So it's pretty cool technology. It's real-time stuff, very valuable for outdoor activities, for aviation, for that kind of thing.

CATHY: That is so cool. And just to be clear, we're talking cloud to ground strikes, not cloud to cloud. Because some people, I think, get a little confused.

PAUL: Right. And cloud to ground has a much stronger current. So they're much more easily detectable. So that's what this network detects, is cloud to ground strikes. Which of course, are the ones that are dangerous, potentially, for here on the ground.

CATHY: See, the things you'll learn. Oh, that is so cool, by the way. I love that sound. Thank you, Paul.

PAUL: Thanks, Wurzer. Thanks a lot.

CATHY: All right. Thanks. Paul Huttner is MPR'S chief meteorologist. You can listen to him this afternoon with Tom Crann on All Things Considered.