The following is a transcription of the May 2023 climate conversation between Denver7 Chief Meteorologist Mike Nelson and Colorado Public Radio’s Ryan Warner for CPR’s “Colorado Matters” show.
Listen to “Colorado Matters” Monday-Friday: 9 a.m.-10 a.m. & 7 p.m.-8 p.m.; Sundays: 10 a.m.-11 a.m.
In this month's discussion:
- What was going on with all that smoke and fog?
- What is El Niño, what does it mean, and how will it affect Colorado?
- How does Colorado's wet ground impact weather?
- Have recent rains and snowmelt helped the Colorado River?
RYAN WARNER, CPR: May has brought heavy rain to portions of our state, heavy smoke too from Canadian wildfires. Meanwhile, severe weather season is getting started, from hail to twisters. A lot to unpack and to help us with our bags, Denver7 Chief Meteorologist Mike Nelson is back. We speak regularly about Colorado climate and weather. And hi again, Mike.
MIKE NELSON, DENVER7: Nice to be with you, Ryan.
RW: When we have had rain and smoke at the same time, it has felt unlike any weather I've experienced. I just kept thinking the rain would somehow flush things out. But Mike, that didn't seem to occur.
MN: It has been a gloomy May. First, we had all of that heavy rain, about eight inches at my house in southeast Aurora. And there was the talk of had that been snow. Yes, that would have been about six or seven feet of snow. But it came as rain and helped us really put a dent in our drought locally, which was great. But the smoke is an import all the way from Alberta, Canada. And that's kind of flung down on the upper level winds into Colorado in recent days and the combination of the cloudy wet weather and then the smoky foggy weather has just been feeling like we moved to Seattle.
May in Denver: A 'friendly and adventurous' weather month
RW: Are we somehow being parked upon by weather systems?
MN: What we've had is the smoke has come down around a big high pressure system up in Canada that has brought them very early hot, dry weather and solid fire problems. Then circling around the front side of that high, the smoke has come in from the Dakotas and then all the way down into mostly eastern Colorado. It hasn’t been as big a problem (in the) mountains and west. But recent showers just in the last couple of days and again today will help to cleanse the air quite a bit going into the weekend.
RW: So, the mountains act as almost a smoke curtain?
MN: Yes, they do. The air was kind of trapped on the eastern plains and really once you came down from about Genesee or something and then looking out across the plains and across Denver was like, wow, what a pall of smoke we have here.
RW: One of your fellow TV meteorologists in town, Chris Bianchi, reported that wildfire smoke may keep miller moths here longer, that smoke particles weigh them down as they try to migrate. Have you had moth encounters, Mike?
What you need to know about the miller moth migration as it hits the Front Range
MN: Oh, yeah. I almost caught one in the studio right in the middle of my weathercast the other night, and certainly plenty of them in the house. Talulah, our little pug, seems to have found an appetite for them. I've caught her eating a couple of them.
RW: They wind up being food and entertainment, I guess. So, the rain seems likely to continue? I mean, I'm kind of thinking of the cliché ‘We could use the moisture.’
MN: We say that all the time. And I guess be careful what you wish for. Because what we've done now, with the heavy rain that we've had is we've set the stage for a stormy summer because the soil is really full of moisture. And so, we start to get the warmer temperatures. You get the evaporation. You get the clouds building, you get the thunderstorms forming, you get more rain, and it's a cycle that builds upon itself. So, I think we're going to have a very active June in terms of severe thunderstorms.
RW: Oh, that's fascinating. The wet ground affects what happens in the sky.
MN: Yep. Just like drought will feed upon drought because if there's no moisture in the soil, or evaporate, you won't get any rain.
RW: Will it feed hail?
MN: Yeah. Unfortunately. A friend of mine who is in the roofing business calls it sky diamonds because when the hail falls, he has a lot of roofs to repair.
RW: Yeah, I have different thoughts about hail — the number of cars I've lost. I understand there's an El Niño weather pattern developing. What does that portend?
MN: OK, the El Niño is the opposite of La Nina, which is what we've been in for the last three years. La Nina is cooler-than-average sea surface temperatures in the Pacific Ocean around the equator. El Niño, obviously, is warmer than average. And we seem to be getting into what we'd call a super El Niño, which is really warmer ocean water. The ocean takes about 90% of the heat from global warming. And so, for the last three years, although we have been in some of the warmest years on record, it's actually been somewhat held down because the sea surface temperatures in the Pacific had been a little bit cooler. All of that heat is now going to be released back into the atmosphere with this big El Niño that's coming. So a lot of the climate experts are predicting this could well be, if not the hottest year on record coming up in 2023 into 2024, it will certainly be right up there. The other thing that El Niño can do for us is it tends to supercharge our summer monsoon. So, when we get into the rainy season, typically late July and August, this year could be a really strong monsoon season. Give us a lot of heavy thunderstorms with flooding rains.
Colorado State University releases predictions for 2023 hurricane season
RW: And what about tornadoes?
MN: Tornado season, we're in it right now. And typically, it is the end of May and June. That's our big time of the year for tornadoes. And the reason for that is we still have fairly strong jet stream winds aloft. And if I ever visited your grade-school listeners and did the tornado dance, you know that the jet stream feeds in to making thunderstorms spin. And that rotation is what gives us tornado-producing thunderstorms, such as what we had about two weeks ago on that Wednesday. We had all the severe weather. We issued Wednesday and Thursday of that week 26 tornado warnings out of the Boulder National Weather Service office in a 24-hour period. That's more than they issued all of last summer combined.
The difference between a tornado watch and warning
RW: My goodness. You know, whenever we talk, Mike, I just get this sense of interconnectedness. The oceans connecting to us in landlocked Colorado, smoke from Alberta connecting to us in Colorado, just the world, when you look at it climatologically, meteorologically it's actually quite small.
MN: Yes, yes. And no borders, I mean, the molecules of carbon dioxide know no land borders. And so they flow all over the world. And as I mentioned before, from the burning of fossil fuel, we add about 100 million tons of carbon into the atmosphere every single day. And every molecule of carbon dioxide — the analogy I like to use is like a feather in a down comforter, redirecting or trapping heat that would otherwise escape into outer space, warming the planet. Now, locally, regionally, yes, you can have colder conditions. But by far, we see that the record high temperatures vastly are outnumbering the record cold temperatures. So, weather and climate are not exactly the same, but they're very related.
RW: You have also added nuance a few times in this conversation by using the word locally. I think that you used it in reference to drought — that locally, the drought has been abated. But if we zoom out to the West, and the Colorado River states, what's the drought picture? Have the recent soakings changed that broader picture, fundamentally?
Task force aims to provide lawmakers with solutions to protect Colorado River
MN: Well, it's improved it. But we would need to have winters like we just had for year after year after year to truly start to make any real push to bring the water levels up in both Lake Powell and Lake Mead. Lake Powell is coming up right now because all of that snow is rapidly melting out of Utah and Colorado. But the amount of use, you know, the number of straws in that Colorado River — 40 million people being served by it. It would take a lot of wet winters in order to change that around.