It's Meteorological Fall, But It's Going To Feel More Like Summer
SPEAKERS
Jim du Bois, Kenny Blumenfeld
Jim du Bois 00:00
Ah, it's September. This is Way Over Our Heads. It's a weather and climate podcast. I'm Jim du Bois. Kenny Blumenfeld's a climatologist. Kenny, my goodness, the switch has been thrown. It was 51 degrees in my backyard when I woke up this morning.
Kenny Blumenfeld 00:18
Yeah, you're right. I mean, it's just like that first day of school whether right?
Jim du Bois 00:22
Right.
Kenny Blumenfeld 00:22
Although it's not really the first day of school in a lot of places but has that feeling that you get after Labor Day where, yeah, it's actually chilly. I woke up and I thought, oh, my goodness, I have to wear long sleeves biking into work today.
Jim du Bois 00:37
The temperature this morning was 34 degrees somewhere in Minnesota. And I can't remember where, Bemidji? Or was it, was it Hibbing? I can't remember, my goodness.
Kenny Blumenfeld 00:47
So, it's okay. Because what's interesting is the various media personalities will often go through the various airports that report generally hourly. And so, you can get kind of real time temperature data from them. What's interesting is in the climate office, we generally don't include those as valid readings. So, there might be an airport, for example, Grand Rapids, or maybe Big Fork or something like that that reports a really low temperature. We wait until, and I think you know about this, Jim, the daily temperature and precipitation readers who use a little higher quality instrumentation that's more standardized, we wait for their data to come in. And that's usually not until the next morning, although sometimes it's the same morning, depending on what time they take their observation. So, it'll be a few hours before we know what the lowest temperature around Minnesota was. But you're right, here on Monday, the 13th of September, we definitely had some northern Minnesota airport stations that were in the 30s. The Ely airport, even at 8am, was still in the 30s, for example. So, well, you can get frost just about any time of year way up north but we're definitely entering that that frost season in northern Minnesota.
Jim du Bois 02:11
Well, Kenny, you and I have talked about this before in previous episodes. And it always seems that right after the State Fair, right after Labor Day, that somehow a switch is thrown, and it goes from...rather abruptly I might add some times, from summer to fall. And we certainly have noticed that waking up some mornings when there's been a certain crispness in the air that wasn't there in late August. And today was the day it really kind of hit me in the, in the face when I got up this morning and I thought it is downright chilly this morning. And there was a lot of dew on the grass, so it was kind of damp. But I thought this has not only the feel but kind of the smell of fall too.
Kenny Blumenfeld 02:53
Oh, the smell of fall. I love it. And you know pretty soon, and maybe even this morning, walk along by the creek or by an area lake, and you'll see that steam rising off of it. That's the, ooohhh, that's, that's, that's a good one. Because what that is, is the warmer water left over from the hot summer, you know, in any summer. But this summer in particular, we didn't have much water, so it was easy for it to get warm. And then you see that steam because that's the water essentially, the warm water, basically being evaporated into the cooler air. And the way that that works is really interesting. The water essentially warms the air right above it. And then that warm air then pulls some of the water off of the surface and puts it into the atmosphere as humidity. So, you see that steam, and then it, and then it very quickly saturates that air right above the, right above the water. So, you see this steam coming off, and it's a sign that your water is cooling down fairly rapidly, in fact, and we tend to lose a lot of standing water, you know, basically, through early November from about early, early, mid-September right into early November, you lose a lot to evaporation. But what you're, what you're observing, Jim is, you know, it's all those terms that people, I say a typical person slept through or tried not to pay attention to. But as you get into fall, the intensity and the duration of sunlight declines. And that shuts down--here's the big one, Jim--photosynthesis, and without, and remember, the easy way of thinking of photosynthesis is that's just sunlight, activating living things, plants, and when the photosynthesis shuts down because the sunlight intensity and duration isn't great enough, then the plants stop essentially sustaining themselves. So, all of those seasonal plants, hardwood trees and grasses in particular, and many crops, they just stop production. And once they stop production, they, they stop sharing moisture that they conduct through their various systems with the atmosphere, the atmosphere gets a little bit drier. We're not quite at that point yet. But on a good cool morning, you can certainly notice that, you know, some of the things have really slowed down.
Jim du Bois 05:18
Well, we did bid farewell to meteorological summer on August 31. We now of course are in meteorological fall. Astronomical fall still a little ways off for us. So Kenny, let's go back and look at the month of August. What was August like for us from a climate perspective?
Kenny Blumenfeld 05:35
Yeah, so August was another warm month. It was a good warm month, but it wasn't like June. But it was, you know, it was up there. And it had highly varied rainfall. So basically, if you lived in the southern part of the state and parts of western Minnesota, you actually did pretty well with precipitation during August, above normal from the Twin Cities West northwestward through Alexandria, all the way south to the Iowa border. Parts of far southeastern Minnesota got absolutely dumped on again. There actually, there's no drought in far southeastern Minnesota. And then, you know, kind of hit or miss areas in western and northwestern Minnesota also had above normal precipitation in August, but then a big swath of northeast Minnesota failed to have normal precipitation again. This was the area, you know, St. Louis and Lake and parts of Cook County, way up in far northeast Minnesota, where they struggled to get even two inches of precipitation. So uniformly, it was warm. across the state. There was actually more heat in terms of hot weather in northern Minnesota than in southern Minnesota. So for example, Jim, International Falls had eight days, 90 degrees or higher. So, you should have been in International Falls, Twin Cities only had four of those days during August. Rochester had none. So, it was an interesting kind of reversal of the geographic pattern of hot weather. You know, it really just had to do with the configuration of the high pressure and low pressure systems that were affecting us. But yeah, so it was kind of a hot month in northern Minnesota and more of a warm month in in southern Minnesota. And then it was very wet in parts of southern Minnesota, and very dry in northeast Minnesota. And that kind of capped off the whole summer. Is that where you're going to go next, ask about...
Jim du Bois 07:34
Absolutely. What was the summer of 2021 like for us in Minnesota?
Kenny Blumenfeld 07:39
Well, you know, here in the climate office, we've been kind of battling some misconceptions that folks have, because when you look at the average seasonal temperature across, across the state of Minnesota, it's actually the second highest that we have on record. So, it was a warm summer for sure. second only to 1988. And that's true in a few places. And several individual locations actually had their warmest summer on record. The misconception that we're kind of working with, you know, is that people tend to say, oh, well, it's the hottest summer on record. Well, here's the thing, what is hot? You know, I know how Jim du Bois, he likes it, he likes it, he likes it 90 or better.
Jim du Bois 08:28
Yes.
Kenny Blumenfeld 08:29
He wants to he, he wants to earn his relief. You know, whatever lemonade, he's gonna drink later on. He wants to earn it. And I think that's how a lot of us really think of hot weather. If it's, if it's 90 or higher, or maybe you have, you know, really, like the highest temperature of the summer is higher, or as high as anything you've observed. We didn't have that. International Falls is probably the one station, and there's a couple sprinkled around northern Minnesota, where we have to give it to them. They had legitimately hot summers by their own standards. So, far northern Minnesota, it was a hot hot summer, and it was potentially the hottest on record. But when you look into southern and central Minnesota, and that's where a lot of these terms are being generated, you know, around the Twin Cities, this was nowhere near our hottest summer because we've had summers, you know, we didn't even rank in the top 10 for a number of days above 90 degrees. And our highest temperature of summer didn't even crack 100 degrees in the Twin Cities. And you know, you've got a couple dozen other years where that did happen. So, you know, it was a very warm summer, no doubt about it. And we saw some of the highest temperatures that we have recorded on an seasonally averaged basis. That means you take the average from June, July and August. No doubt about it, warm, warm summer, and some parts of the state were hot. We just aren't comfortable saying this was our hottest summer yet because anybody who experienced 1988 would say, yeah, what about that one? Or people who just know the history and know what happened in say 1936, for example, when, you know, there was 14 days in July in a row where the temperature was 90 or higher, and I think something like eight of those days, it was over 100 degrees and including our all time high temperature record. And since we weren't anywhere near those types of metrics, you know, this is where, you know, dorky climatologists get, you know, we just like to keep people on message a little bit here. Because if you live in Portland, Oregon, for example, they absolutely had some of the hottest weather they ever recorded. No doubt about that. And we can't really claim to have had the same experience that Portland had. And we want to make sure we use those types of terms when we know we did have that kind of summer, and we haven't had that one yet. So hopefully, it's not coming. But you know, gosh, seems like almost anything can happen now.
Jim du Bois 11:11
How is our drought situation shaping up?
Kenny Blumenfeld 11:14
Yeah, that's a good question. So you probably noticed, Jim, nice, green lush vegetation in South Minneapolis.
Jim du Bois 11:22
Oh, yes. It came back, it came back.
Kenny Blumenfeld 11:23
Yeah, I think that, you know, Minnehaha Falls came to life. This allows, I think people in southern Minnesota in particular to kind of forget what else is going on. So, in the Twin Cities area, we got a good push of precipitation. And certainly southern Minnesota has done better. We still have large deficits, anywhere from four to eight inches, depending on where you are in most of southern Minnesota. Parts of southeastern Minnesota, there's effectively no long term deficit now. And so, it's not clear how long they'll remain in official drought conditions. But in northern Minnesota where the precipitation was a little more spotty, and in many cases, scarce, the drought, if anything intensified during August. And you know, I think if I were in northeast Minnesota with all the fires from the summer, I would not be resting on our laurels just yet, because they didn't get as much precipitation as other parts of the state. And they're coming into that same thing, we just described the whole mechanism that makes it crisp in the fall. That also dries out standing, living vegetation. So, if you've already had really dry conditions, and then the dry season kicks in where you don't have photosynthesis so you don't have that evapo- transpiration where the water comes out of the plants and goes into the atmosphere, that's really when the main fire weather season is. So, parts of northeastern Minnesota have a two year deficit going back to February of 2020. So, it's like 18 or 19 months deficit on the order of a foot of rainfall or precipitation. So, they're really low. They need more precipitation. They're coming into their dry season. Much of northern Minnesota is still in that extreme level of drought officially, and we still have a little swath of northwestern Minnesota, kind of from the International Falls area through Red Lake that remains in what's called D4 or exceptional drought, the highest level of drought on the US Drought Monitor. So, I would say southern Minnesota can feel a bit better. We're still behind, but we're in a much better position than northern Minnesota where they haven't had as much help and where the deficits are much larger.
Jim du Bois 12:38
So, what do the weather trends look like in the days and maybe weeks ahead? Anything interesting that you've seen?
Kenny Blumenfeld 13:52
Yeah, actually, the most interesting thing starts I mean, there's one shot today, that's Monday, September 13. I don't think it's a major outbreak of severe weather. But you know, the Storm Prediction Center has indicated slight risk of severe weather over parts of southern Minnesota, basically south of the Twin Cities. I think I-90, that kind of I-90 area, and maybe a little bit north into say Mankato and Red Wing. So, a chance for severe weather this evening. And heavy rain will also be possible over parts of southern and central Minnesota. Again, I don't think this is the event of the year at all, but there's a chance that, you know, decent signal that some areas are going to get another one to two inches, kind of I don't know if it's irony, but a lot of that rain looks most likely in the areas that you know, needed the least. They'll take it. I think it's good to put it in the bank. When you're in a drought, put as much water in the bank as you can, but there are parts in northeastern Minnesota that it probably won't see anything from this. Then we move into a really warm pattern especially as we get, you know, later into the week and into the weekend. The outlook from the Climate Prediction Center has an 80% chance likelihood of being above normal for temperatures in the six to 10 day period. And in the eight to 14 day period. So, we're getting, you know, right around the Fall Equinox and slightly after that. So, you know, September 18, through basically 25th or so 26, that period has a very high likelihood of being above normal for temperatures. And depending on where in the state you are potentially anyway, above normal for precipitation. Essentially, what the models are showing as we move into kind of a warm and stormy pattern. And we've seen this before, my colleague and I will joke about oh, every time it looks like the whole state of Minnesota is about to get really warm and really wet, it ends up being that southern Minnesota gets pounded and northern Minnesota just gets hot, so I'm not betting on anything yet. All I know is that the professional forecasters are looking ahead and seeing a lot of precipitation chances. The European Model, which is one of the highly regarded forecasting models, shows several inches of precipitation over parts of Minnesota over the next 9, 10 days. Again, is that really what's going to happen, or is it just going to hit Rochester again? That right now, I can't tell you, but it does look like a warmer pattern, you know, so another chance of showers and thunderstorms on Thursday. And then again over the weekend. And then again, we get into a really warm pattern by the end of the weekend where we could have some 90s creeping back into Minnesota, if things hold up for Sunday.
Jim du Bois 16:43
Well, it may be meteorological fall, but it sounds like summer-like weather is going to persist for a while.
Kenny Blumenfeld 16:50
Yeah, I mean, you'll like it, Jim. I'll like it too, I think, you know, it'll still be relatively humid. So, we're not yet to that hot, dry type of fall weather that sometimes you get. So we'll have to see. It's not quite the same as what you get in July. But you know, it could be an interesting time. So starting with today, thunderstorms very likely over parts of southern and central Minnesota. Almost guaranteed somewhere in that region this evening with severe weather most likely south of the Twin Cities. And then other chances late in the week and over the weekend.
Jim du Bois 17:27
Well, keep an eye on the sky and an ear or an eye to your favorite source of weather information. And Kenny, great chatting with you as always. Enjoy and we'll check in with you again next week.
Kenny Blumenfeld 17:39
Great, thanks. Good talking with you too. Jim.
Jim du Bois 17:41
This is Way Over Our Heads. It's a weather and climate podcast. I'm Jim du Bois. Kenny Blumenfeld's a climatologist. We'll catch you next time.