♪♪ Most of Iowa is abnormally dry with some areas experiencing moderate to severe drought.

We'll discuss the impact and the outlook with State Climatologist Justin Glisan on this edition of Iowa Press.

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♪♪ For decades, Iowa Press has brought you political leaders and newsmakers from across Iowa and beyond.

Celebrating 50 years of broadcast excellence on statewide Iowa PBS, this is the Friday, June 9th edition of Iowa Press.

Here is Kay Henderson.

♪♪ Henderson: Our guest today compiles the data that is released as the Iowa Crop and Weather Report every Monday during the planting and growing season in Iowa.

He also contributes the data that is used for the U.S Drought Monitor to come up with a map that shows where Iowa may be abnormally dry or critically dry.

Justin Glisan has been on our program before.

He is the State Climatologist in the Iowa Department of Agriculture.

Welcome back to Iowa Press.

Glisan: Wonderful to be back.

Henderson: Also joining the conversation, Linh Ta of Axios Des Moines and Erin Murphy of the Gazette in Cedar Rapids.

Murphy: So, Dr. Glisan, drought conditions to varying degrees across the state right now.

Just kind of summarize, how bad is it out there?

Glisan: So, we're backsliding back into drought.

We've had three years of a pretty particular pervasive drought across much of the state, especially Western Iowa.

We see D2 to D3 conditions on a scale of D0 to D4.

So, when those more pervasive and dry areas we've seen precipitation deficits really stack up on the order of 15 to 25 inches.

This is reflected in lower stream flows, but also diminishment in soil moisture within the profile.

So, agriculturally we really need that soil moisture profile when we do get dry to sustain the crop.

And over the last few weeks we have expanded drought and abnormally dry conditions.

Murphy: And it's through -- it expands through areas of the state -- to varying degrees -- Glisan: Yes, especially you look at a Northeast to Southwest swath, basically D0 or that abnormally dry category, not drought but representative of 30 to 60-day dryness in terms of precipitation.

You look on the phalanges of the state, dry, very dry conditions in Western Iowa and we're starting to see D2 conditions develop in Southeastern Iowa and then around Waterloo as well.

99% of the state is in D0 to D3 conditions.

Murphy: And do you have any data, anything telling you what's to come?

Is it going to get even worse?

Is there good news on the horizon?

What's out there?

Glisan: I think there's good news on the horizon.

Now, it might take several weeks, but yesterday officially we were in an El Nino advisory.

We have been in three years of what is called La Nina or the cold phase.

And these are sea surface temperature anomalies in the Pacific that impact where thunderstorms set up.

Where those thunderstorms set up dictates the storm track over the United States, three consecutive years of La Nina since the beginning of drought, only the third time in which we've seen this since 1950.

So, that transition to El Nino does suggest if we look at analog years or years in which we've seen that transition of slightly cooler temperatures but not as dry as that La Nina phase.

So, I think there is good news on the horizon.

Ta: If you look at the Iowa Drought Monitor it shows that different areas of the state are under either severe or extreme drought.

What do those mean?

Glisan: Yeah, that's a great question.

So, we take a hundred years of data basically and we look at percentiles.

So, historically when would we see drought occur at a specific category?

That D4 extreme, or exceptional drought, would happen once every 50 to 100 years at a given location.

So, that D2, D3 category, several decades that you wouldn't see that condition arrive.

And that is just a reflection of 153 weeks of drought that we've been in since July of 2020.

That broke a record.

The previous record was 151 weeks since the Drought Monitor came into inception back in 2000.

Ta: And how do you measure drought?

And what do you base it off of?

Glisan: Several different hydrological variables.

You look at stream flows, you look at precipitation deficits, you look at soil moisture profiles.

You also look at temperatures.

In drier conditions, when you see temperatures that are higher than normal, that exacerbates drought condition by producing an atmospheric thirst.

When that atmospheric thirst develops, coupled with windy conditions and low relative humidities, you're sucking any moisture out of the surface that you can find and that's where we are right now, in rapid onset drought.

And that, when we get into a phase like that, you have all these characteristics, this very stagnant flow that we've been in, coupled with this wildfire smoke as part of that circulation feature, that is where we really start to see moisture being extracted in concert with the lack of precipitation.

You look at May, the 21st driest May in 151 years.

You look at March, April, May, meteorological spring, the 16th driest spring on record.

Henderson: Another agency in state government, the Iowa Department of Natural Resources, issued what is called a drought watch this week.

What is that?

What am I as a citizen of Iowa supposed to do when I hear my state government say, there's a drought watch?

Glisan: So, this is hot off the press, the Iowa Drought Plan.

We spent 15 months writing this with the DNR, my colleague Tim Hall, and Homeland Security and Emergency Management.

We haven't had a drought plan for the state and we had a water plan that was written in 1985.

So, we needed an update.

We were getting into very pervasive drought conditions in June of 2021 -- the last time, or one of the times I was on -- and we needed a plan to put in concert all the state agencies how we would address various sectors of drought across the region, across the state, but also look at the forecastability of drought.

If we have specific trigger tables and we're moving in a dry direction we can do things at the state level to pre-position resources, to get that information out to stakeholders, to farmers and to producers to let them know that perhaps there is another pervasive drought on the horizon and as the State Climatologist I am also the State Drought Coordinator.

So, having all this information consolidated in one document I think has been a very wonderful reflection of what state government can do.

Henderson: So, does it mean if I am the manager of a city water system I might advise the people who live within the city limits to quit watering their lawns?

Glisan: Absolutely.

And this is all voluntary.

There is no enforcement here.

But what we would like to see municipalities do is address those issues, don't water your lawns during the day, maybe not have a car wash when we do get into particularly dry conditions.

All the five state drought regions are in watch.

Now, the categories go from normal, watch, warning and to emergency.

So, the enactment of these watch levels, along with the trigger tables, hopefully can get us a better consolidation of information that we can use to address drought concerns because we know drought will be with us in the future.

Murphy: I want to go back just a little bit here.

A few months ago on this program we were chatting with some folks from the National Weather Service and at that point we were talking about exceptional snow pack in Minnesota and Wisconsin and flooding on the Mississippi River and now here we are a few short months later talking about drought.

How do we get from that point A to point B so fast?

Glisan: Our extremes are co-located, they are occurring amongst each other, dry extremes, wet extremes.

We have talked about 2018, the wettest year across the northern third of the state, D3 conditions across Southeastern Iowa.

That record snow pack across Minnesota and Wisconsin really fed the Mississippi, near record levels along the stream gauges there, but not large-scale noticeable impacts, which was refreshing given the possibility of the flooding there.

Now, we get into a more drier pattern after the 4th wettest winter on record, the 11th wettest February on record, backsliding back into drier conditions.

So, overall, we just have to be cognoscente what the trends are showing us and what the projections are showing us.

We're going to have wet, dry, warm and cold extremes together moving forward.

Ta: And how much does climate factor into these extremes that we're seeing?

Glisan: A warmer atmosphere holds more water vapor and more water vapor availability leads to more precipitation events, more precipitation, higher intensity rainfall events more often.

When you have more water vapor available in the atmosphere it takes more water vapor loading to produce a meteorological event, so rainfall.

But, you get these really intense rainfall events, two to three inches over several hours versus those historically gentle rainfalls over 24, 48 hours.

You look at the distribution of heavy rainfall events, the probability of a 4+ inch rainfall event historically is 0.01%.

We've tripled that over the last 30 years, a small probability but definitely tells you something in the climate system.

We're getting warmer and wetter and this has implications on those extremes that we talked about.

Henderson: Farmers have the ability to pick certain seeds to put in the ground that do a better job when it's dry as opposed to when it's wet.

Did they get an early warning here given how dry the fall was?

Glisan: Farmers are some of the most intuitive people on Earth in terms of weather because they have been on their farms for decades, some heritage farmers 150 years.

So, they've seen the changes in the weather that we have across the state.

And with the hybridizations that we've developed, not we, but that science has developed, we're really seeing drought resistant varieties, but you also have if you plant a drought resistant variety and it gets wet you can have also negative implications.

These climate outlooks that we put out seasonal do give us good guidance in terms of temperatures and precipitation regimes that we can see on the large scale.

Knowing the phase of El Nino or La Nina allows us to look back at analog years in which that has occurred to give us a better idea of growing season conditions, at least when we're in the fall and winter.

Also, knowing how much recharge we've had in subsoil moisture profiles can tell us, again, what hybridization or what variety of corn or beans that we plant given the wet or dry conditions.

Henderson: It was some farmers put seed in the ground when it was cold and they had to replant.

What did that cold part of the growing season, what impact might that have on overall yields?

Glisan: I think we're not going to see widespread impacts on yields.

We had a lot of replant after this chill inhibition with the seed going into cooler soils with wetter conditions and then a temperature swing into the colder realm.

We've had replant, as I mentioned.

But, given the growing degree day units that we've stacked up with these 80, 90-degree days, especially in April and May, we're ahead of the five-year average.

The corn and beans are emerging.

We've had some crusting issues with lack of rainfall, which is an emergence issue, but I'd rather be dry on the front end of planting as opposed to getting into July and August when we're really going through the physiological maturity of the crop, especially corn tasseling and pollination.

We need timely rainfalls throughout the teeth of the growing season.

So, seeing this potential shift into El Nino, which we are in now, and the potential for the weather patterns that set up, I'm pretty confident that we're not going to see any yield loss because of early planting.

Henderson: So, I would like to circle back.

You said there was good news on the horizon.

When will we get to that horizon?

Are you talking about July and August?

Or are you talking about 2024?

Glisan: The whole thing.

So, it takes several weeks for the ocean and the atmosphere to couple together.

That is how El Nino and La Nina work.

You get warmer sea surface temperatures in the Eastern Pacific, the atmosphere says hey, lots of fuel to work with, I'm going to pop up thunderstorms.

When that occurs we're officially in El Nino.

It will take several weeks for the large-scale atmosphere to re-equilibrate into a new configuration in terms of circulation.

We see that stagnant air mass on the East Coast with all the wildfire smoke from Canada, very pervasive conditions there.

It's starting to move off into the Atlantic and we are seeing some semblance of a pattern shift.

This could go hand-in-hand with the potential for that El Nino signature.

High probabilities in the 80% to 90% range of El Nino lasting through the end of the year with a 56% potential of a strong El Nino, something not as monstrous as 2016 or 1998, but definitely a pretty strong El Nino.

Murphy: Talking about unusual or extreme events, we're now familiar with derechos in Iowa because of recent years, there was a recent event that I wanted to ask you about, essentially a Dust Bowl, a dust storm over in Illinois, it led to a crash, a 72-vehicle crash on the highway.

How unusual is something like that?

And is that becoming more common?

Is that something we have to be paying more attention to?

Glisan: That particular event on I-55 was very anomalous.

I don't think we've seen anything like that in the Midwest since the Dust Bowl era.

A lot of factors came into play, a lot of factors have to come into play for an event like that to happen.

Unfortunately, I think seven or eight fatalities from that crash.

The weather service the next day, similar conditions issued a dust storm warning.

Looking back at the records for the Midwest and for Illinois, we had never seen a dust storm warning.

So, from what we were doing in terms of cultivation of the bare soils along with strong northwesterly winds and very dry conditions easily lofted that soil and that is where we got into that situation.

Another notable event was that May 12, 2022 derecho across South Dakota that produced the haboob.

The haboob is a dust storm that we typically see in Africa or the desert Southwest.

So, while these are one-off events, we are seeing features lock into play that will give us more extreme events that we haven't necessarily seen over the near-term.

Ta: You mentioned the Canadian wildfires.

We saw the impact of it here in the Midwest and how it's going along the East Coast as well.

Is it possible that we could continue to see the effects or have it come back to us here in Iowa?

Glisan: Maybe not from the Canadian wildfires.

We could get into another large-scale weather configuration that would bring that smoke further south.

But, we're going to have to have the foreknowledge that wildfire season is going to be with us in terms of smoke either from California or Canada.

California has been extremely wet.

What that means, though, is they are growing fuels for the next drought or for the next wildfire season.

So, the expectation during spring and summer is that we will have wildfire smoke across the state, across the Upper Midwest.

This has implications on photosynthesis, but also on human health and air quality for our cattle and pigs.

So, we have to build this in as something that we're going to see more often.

Henderson: We haven't perhaps seen as often as we might normally tornadoes this season.

Why?

Glisan: So, you look at the last three years, we've been in a severe weather drought.

And, for lack of a better term, when you're in a severe weather drought you don't have thunderstorms to give us rainfall and we get into drought, 153 weeks.

We had a start to this spring season where we had a lot of thunderstorms, a lot of severe weather, we had some tornadoes, very weak.

If you look at the climate trends, it looks like Tornado Alley is shifting further south.

We have a more active storm track in what we call Dixie Alley where you have wider-scale tornado outbreaks.

If you look at our records across the state and across the Midwest since 1950, we're seeing less one-off thunderstorm tornadic, tornado events.

We're seeing more outbreaks.

And we've noticed that since the middle of last century.

And that has to do with the warmer atmosphere, more water vapor availability, more instability building in.

So, moving forward over the next several decades we can expect conditions for severe storms to increase, especially in that March, April, May timeframe.

So, while it looks like we're in a severe weather drought right now, there are articles out there, there are peer review journal articles that say the conditions in a warmer atmosphere with more water vapor will give us more thunderstorms and severe weather.

Henderson: What role does humidity play in all of this?

Glisan: So, I'm from St. Louis and we know what humidity is in St. Louis.

Humidity is that low level moisture that we have, especially with corn sweats, in concert with having this low-level moisture availability, number one, oppressive heat indices, especially in summertime.

But, also less moisture stress on crop because there is water vapor availability at the surface.

But having water vapor available during the growing season gives fuel to thunderstorms.

These systems don't drag moisture with them, they look for moisture to use.

And we got into a situation in 2020 and 2021 in West Central Iowa where you had thunderstorms forming and then just dissipating or moving around because there was no low-level moisture to work with.

But, overall you look at the trends for relative humidity moving forward, more.

Murphy: I wanted to go back real quick to when we were talking about the wildfires and the impact we're seeing.

How much does climate generally play, from how those fires start in the first place and having dry conditions to how the hazes that we see throughout the country, how much does climate impact the spread of those phenomenon?

Glisan: What I look at are the large-scale patterns and how persistent those large-scale patterns are.

When you get stuck in a mega drought like we had on the West Coast with California even up through Washington you're growing fuel, you're growing fuel in the mountains and when you get into drier stretches anything can set that fuel off, especially given how dry we get during drought regimes.

So, we're just going to, as I mentioned, have to be considerate of the fact that wildfire season will be with us, it might not be every year, but given that these extreme events are locking in more persistently and for longer time spans, that is the expectation.

Henderson: You mentioned mega drought, and there was one in California that lasted how many years?

Glisan: You look back at records of 1,200 years of at least fingerprints of this drought existing.

Henderson: So, I had another meteorologist who works for the USDA tell me that Iowa really is not in a position to do that because of the Rocky Mountains or something.

So, could you explain why we really don't fear the idea that this three years of drought conditions in Iowa will stretch into a decade?

Glisan: We're well situated in the continental United States.

We see a lot of Tornado Alley here, right.

All the ingredients come together, cold Canadian air, moist Gulf air off of the Gulf of Mexico, warmer weather and air masses coming through all connecting in the Midwest.

So, we have an active storm track.

Three years of drought would belay that, would say no, we've seen less active storm seasons.

Our soils are also, can hold a lot of moisture, some of the richest soils on Earth.

That soil moisture also helps fuel the growth of our crops and our vegetation so it doesn't dry out.

Now, we can get into dormant patterns in fall and spring where you can see fueled fires on radar, you can see the plume go up.

But in terms of the widespread nature that we see in Canada, 8.5 million acres, California several million acres back at the height of the wildfire season, that pervasive wildfire season.

We really don't have those ingredients here.

We can see wildfires but not on that scale and not on that temporal span.

Ta: Some of the drought conditions are described in the state as a 50-year drought.

Are we going to start seeing those become a 10 or a 5-year drought condition?

Glisan: So, we talk about return periods with flooding.

You get 100-year flood, 500-year flood, we're kind of moving away from that verbiage precisely because you bring that great point up.

We're seeing wetter wets and drier dries.

We're seeing these percentile events happen more often.

So, the paradigm in which we address flooding versus drought, we're starting to see a shift in how we scientifically view those events.

Murphy: We were chatting just before going on the air here today and you had some really interesting background on how you got into climatology.

I'd love for the viewers to hear this.

You seem destined from a very young age apparently to be a climatologist.

Glisan: I love the weather and I am scared to death of the weather.

I was a Weather Channel kid, grew up outside of St. Louis and as a child, your child's mind is different than when you grow up.

Things are taller, things are scarier.

But we had bout and bout of severe weather across St. Louis and I remember walking to school, first or second grade, elementary school was a block away, saw these clouds rising at the horizon, now I know them as cumulus castellanus clouds, but these are those castle turrets that go up in the morning before the sun has really allowed the surface to heat up.

So, artificial forcing for buoyancy or updrafts.

That afternoon we had a very bad severe storm that went through St. Charles that produced a tornado south of the city.

But that always stuck in my mind that we can forecast the weather, but we can't control the weather.

So, my father took me aside and said, you're either going to be scared your entire life of severe weather, or you're going to learn everything you can about it.

And I have a Ph.D. in atmospheric sciences.

So, I thank him for that foreknowledge as a little kid.

I also don't eat breakfast because as a kid I was afraid of severe weather, it would happen to evacuate breakfast by throwing up at school.

So, here I am.

But I still get goosebumps thinking about what I do and the people that I serve and I couldn't think of a better job to have.

Henderson: One of the ways that people have begun deciding I need an umbrella or I need to go inside is they look at their smartphone.

Sometimes when I look at my smartphone it tells me it's raining and it is not raining where I am.

Where do those forecasts come from?

And what is your advice to Iowans who want to get the best information about what weather they may face throughout the day?

Glisan: Become my friend.

I get text messages all the time.

Seriously, those weather forecasts come from your nearest airport because the airports take hourly observations.

Now, of course, some of those apps have proprietary modeling that can give us hourly information or forward information.

But overall, the National Weather Service is an excellent source of information.

Again, those weather apps, if it's raining, if it's not raining, I was caught out in the rain the other day because of the same reason, which I feel like a fool because I'm the State Climatologist.

But overall, those data sources are great.

Rain is, again, hit or miss.

But, I'd be happy to be stuck out in a rain shower given the conditions that we have now.

So, again, the National Weather Service is my trusted source of information.

They do an excellent job.

Henderson: So, to prep for your next appearance, we know about derechos, we know about haboobs.

What is the next weather term that we need to know?

Glisan: Ooh, that's a good one.

I think we've used up the lexicon right now.

I might have to invent one.

As you know, my predecessor, Dr. Gustavus Hinrichs, termed the word derecho back in 1888.

So, I'll be working on that for my next time around.

Henderson: Well, thank you for being here this time, Justin Glisan, the State Climatologist, and my colleagues here.

If you would like to watch any episode of Iowa Press, you may do so at iowapbs.org.

For everyone here at Iowa PBS, thanks for watching.

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