National Weather Service Meteorologists

Iowa Press | Episode
Apr 28, 2023 | 27 min

On this edition of Iowa Press, Donna Dubberke, meteorologist-in-charge, and Brad Small, lead meteorologist, with the National Weather Service Des Moines, discuss severe and extreme weather, its impact on Iowa and the broad range of duties of the NWS meteorological team.

Joining moderator Kay Henderson at the Iowa Press table will be Erin Murphy, Des Moines bureau chief for The Gazette, and Clay Masters, lead political reporter and host for Iowa Public Radio.

Program support provided by: Associated General Contractors of Iowa, Iowa Bankers Association and FUELIowa.



As the saying goes, if you don't like the weather in Iowa, just wait five minutes, it'll change. Flooding, drought, snow in April, we'll talk about it all with expert meteorologists on this edition of Iowa Press.


Funding for Iowa Press was provided by Friends, the Iowa PBS Foundation.

The Associated General Contractors of Iowa, the public's partner in building Iowa's highway, bridge and municipal utility infrastructure.

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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, April 28th edition of Iowa Press. Here is Kay Henderson.


Henderson: Neither snow nor rain nor heat nor gloom of night will keep our guests today from telling us about the snow and the rain and the tornadoes and the derechos and that are heading our way. Our guests today are from the National Weather Service office in suburban Des Moines, in Johnston. They are Brad Small, he is the Lead Meteorologist at the office and Donna Dubberke is the Meteorologist-in-charge at the National Weather Service office in Johnston. To both of you, welcome to Iowa Press.

Small: Hello, thank you.

Dubberke: Thanks for having us.

Henderson: Also joining our conversation, Clay Masters of Iowa Public Radio and Erin Murphy of the Gazette in Cedar Rapids.

Murphy: So, we wanted to start with because right now we're dealing with some flooding issues potentially in eastern Iowa along the Mississippi River, in the Quad Cities area especially. You folks are in the Central Iowa office. What is your data? What are your models showing you? Are we going to see similar issues in other areas of the state? We'll start with you, Brad.

Small: Yeah, well the good news is that the issues are relegated to eastern Iowa and the Mississippi. Almost all of it is caused by the snow melt and the biggest snow pack was in Minnesota and Wisconsin. So, that is driving all of this, which is somewhat unusual because a lot of our spring floods are kind of a cumulative thing that started in the fall with maybe a wet fall and then we had a big winter snowfall and then spring rains started. And this is kind of unique that it's almost entirely driven by the snow pack. And we're actually kind of low on our rivers in Central Iowa and the Missouri is quite low too. So, that is the good news is that the threat is relegated to the Mississippi River.

Murphy: Yeah Donna, maybe pick up where Brad touched on there, it is more on the dry side in other areas of the state, right?

Dubberke: Yeah, a lot of the state in the latest drought monitor -- what level we're officially at --

Small: Yeah, there's D3 and D4 drought in far northwest Iowa that hasn't really changed much, that has been that way, and it will take a lot to move that. That won't be just one event, it will be multiple events that has to happen for that to change.

Henderson: So, for people who don't have burned in their brain the drought monitor that we see online, what is a D3 and a D4 mean?

Small: Yeah, those are drought categories. So, D0 is abnormally dry and it goes all the way up to D4, which is the worst-case scenario.

Henderson: And we have a portion of the state that still has that.

Small: Yeah, up in the Sioux City, northwest area, Sioux City area, yeah.

Murphy: And Donna, Brad also touched on this referencing the snow pack north of our areas over there in the eastern part of the state. Flooding is something we watch for every spring. What are some examples, and that is obviously one of them, that folks like you look for to help you best determine and give some advance warning to areas that are going to deal with this? What are signs you're looking for in other areas that help inform what is coming to Iowa?

Dubberke: Yeah, so in the spring the snow melt is kind of a unique time that we look at that. But there's also looking at the fall, the previous fall. What's the ground condition like underneath? Is there a lot of groundwater? Soil type plays into it when we get into heavy rain periods. Then we're looking at how much is it going to rain? But what is it landing on? Is it going to be runoff? And then when we get crops in the field that changes the runoff patterns as well. So, terrain will play into it and how fast it runs off. In the early spring, another thing we have to think about is, is the ground frozen? But now we're past that time of year. So, for this time of year it's a lot about how much rain we're going to get and how much time, how short of a period of time and what the ground conditions are it's falling on. That's the main things.

Masters: I'm interested, so the National Weather Service serves as kind of in my mind a hub to all these different organizations out there, to meteorologists at local TV stations to morning hosts on public radio that are looking at the National Weather Service readouts to city governments that are trying to make plans for what is going to happen. Let's think about a place like the Quad Cities where there is Bettendorf and Moline, Illinois have flood walls set up to anticipate the flood that is coming. Davenport has more of an open area that can naturally serve as a floodplain with some of these HESCO barriers that have been set up to prevent flooding in their downtown area. What is the role that the National Weather Service, folks like you have in helping city governments, helping leaders in these cities prepare for these things so they know how to make the best decision for their municipality? Brad, we'll start with you.

Small: Yeah, that's one of the Weather Service's biggest missions is decision support for our core partners, which could be local officials, emergency managers, fire departments, whoever is trying to do this flood fight. So, we provide the information in the short-term and the long-term, we provide outlooks in the order of months to give them an idea, which we did luckily in this case that hey we can see this one coming from a long way away because it's a snow melt flood. And then in the shorter term we provide daily river forecasts and give them information on timing, magnitude, maybe some uncertainty depending on if there was rainfall involved in this flood, which there's not really, but if there was there would be uncertainty hey if the rain falls here it may go into this river, it may not go into that river. So, that's some of the information we try to give them, anticipate their questions and provide them information so they can make the best decisions.

Masters: So, Donna, it's more of a way of explaining, giving the facts and figures so that those local municipalities and leaders can make the decision that is best for them?

Dubberke: Yeah, exactly that. I think one way I like to think about it is we're kind of, we turn data into information. So, we have lots of data about what's the status and we have models that forecast and predict. And our job is to take that and help interpret it, that people understand where the confidence is, where the confidence is not, so they can make the best decisions they can make. I know that in the Quad Cities area they're doing, and in La Crosse as well that covers the northern part of the Mississippi there, they're doing daily briefings to partners on what is the latest and how things have changed or not changed. And then partners can sit in or not if they have time. But just to try and keep that information flowing. With a river like the Mississippi you have the Corp of Engineers that's involved, the USGS and other agencies as well, so keeping the state plus local plus any federal entities updated and just as things change because it doesn't usually stay the same as what you first think. It does evolve. So, that's kind of a constant challenge.

Henderson: So, you mentioned La Crosse and if our viewers don't know the La Crosse, Wisconsin National Weather Service office provides forecasting for a portion of northeast Iowa, there's a Quad Cities office that does for portions of Iowa. Your office obviously does. There's one in Sioux Falls?

Dubberke: Sioux Falls has the northwest and then Omaha has a few counties in the southwest as well.

Henderson: So, all of those offices issue tornado watches and warnings to Iowa. I'm wondering if both of you could address some news that we're hearing sort of that maybe Tornado Alley, we've always considered that Iowa is in Tornado Alley, may be expanding. Donna, is it?

Dubberke: It's a good question. The last few years the climatology has certainly been different than what we were used to. We used to think of April, maybe starting in March in the south and April was a really busy tornado month and then with a peak in May. And we still have that statistically speaking, but the last few years have not been what we would, any of us would define as typical. We have much more, maybe a little bit of activity in early April and then it would quiet down. It seems like our season is shorter and a little more intense. So, I don't know from a national standpoint, we also are seeing a lot more in the news about the Southeastern United States and their Tornado Alley, which they have always had a climatology for that. But, so I don't know. Brad has a lot more experience here in the central part of the state.

Small: Yeah, I think a lot of the Tornado Alley historically, like when I was a kid Tornado Alley you think of these big isolated storms and big large tornadoes, and as we've advanced with better resolution in radar data and satellite information to after the event to look at and say hey, this storm did this and we might not have known about that 20 years ago. So, we can look at that more and that has maybe expanded it more into the Southeastern part of the United States where the classic supercell tornado may not have been as prevalent as Oklahoma, Kansas or Texas. So, I think that's some of the things that have kind of expanded the footprint of what we consider Tornado Alley.

Henderson: So, one thing I don't remember hearing as a kid when I listened to the radio and all the weather that was being forecast from the folks was derecho. Let's talk about the fact that we've had three of them after really many people not even knowing what a derecho was. Brad, what's at work here?

Small: Yeah, so really rare events have happened. We've had derechos before. We had one right here in Johnston in the late '90s, '98, which affected a great deal of Central Iowa and we've had other ones. But it's really tough to tell if it's a larger trend. We had kind of a cluster there in 2020 and then the December one, which was really remarkable, I think that was the August one was 2020 and the December one was '21 I think. So, that's just remarkable on many levels that we had it to that scale and it produced a record number of tornadoes and it occurred in December, which was uncharted territory. So, it's certainly something to keep an eye on whether it's a long-term trend. The term is certainly more prevalent now than it used to be. A lot of Iowans didn't even know what a derecho was and now we've had two in two years and that has kind of bumped up the awareness. And that’s a good thing too. We're probably not going to predict a derecho days ahead of time. But if we mention that word people can calibrate more better what is to be expected.

Henderson: Donna, Brad just said we're not going to predict it a couple of days in advance. Oftentimes you're able to say we see weather conditions that may spawn a tornado. Why is a derecho different?

Dubberke: Yeah, there's a very specific set of conditions that need to be in place for a derecho to develop. So, it's common to get thunderstorms or a squall line, which is a line of thunderstorms, it's really common to get that. But the conditions of a derecho is a high-end squall line, it's an extreme type of that, so it's a very specific set of conditions that just are down to a level that are not well captured by models or by any of the data until you get within a few hours sometimes, maybe the day before. So, typically what would happen is we see, okay, first we see maybe seven days out there are going to be storms. Then when you see that signal increasing and getting clearer and clearer you know, okay, this could be high end, there's a lot of instability is one of the things we look at. And then we'll just see. But is that going to materialize as the days get closer and closer? And so usually it is kind of a ramping up as the event approaches in most cases.

Murphy: So, speaking of trying to alert folks about severe weather events like these, I'm curious to hear from both of you, and Brad we'll start with you on this one, the way people consume information has changed so much over time and especially lately with smartphones and other digital technologies. How has that changed the way organizations like yours have tried to get these notifications and these notices, these warnings and watches, out to people? And how, in what way is that effective and where are there maybe still some blind spots in the way groups like yours try to give people a heads up?

Small: We try to promote redundancy, multiple ways to get the information. There's weather radio, there's a smartphone app, there's built into most phones there's WEA, wireless emergency alerts, and then there's our messaging in particular that we try to, really our only great vehicles are social media and our website when we do that. So, we try to graphically display where the threat areas are and not make the graphic super complicated and easy to digest. But tell people the what, where and the when. Those are the basic questions we try to answer in our messaging to try to, whatever the threat is whether it's a snow storm or a severe weather event, to try to let those people know those three basic things for their location.

Murphy: You mentioned the smartphones. Tell us if you could how good those are at -- so I have my phone and it knows where I live, but if I'm now in, I live in Polk County but on this afternoon I'm in Harrison County, are those apps equipped or am I getting alerts from --

Small: Yeah, it depends. So, we recommend having more than one smartphone app and dig down into them. Don't just let them sit by their defaults. A lot of them are highly configurable. You can say I want this alert, I want that alert, I want it to follow me, I could turn on different locations. If I live in Johnston but I'm in Okoboji a lot I might turn on the alert for Okoboji too just to increase the knowledge and if my family is up there I can call them and say hey, it looks like there's a bad storm coming. So, with your smartphones you try to make sure you have some knowledge in it on the app in particular to know all its functionality and what it offers.

Murphy: And Donna, in this block I also want to make sure because it seems like people still need this reminder, define for us if you would the difference between a warning and a watch.

Dubberke: Sure. Yeah, the watch comes first. The watch says that the ingredients are in place and it is something to watch out for. But a warning means that something dangerous or life threatening is happening and you should take immediate action. So, one way to kind of remember that is that the watch is first, is watch for the warning. That's kind of a phrase that you can use.

Murphy: And real quick, we asked state climatologist Justin Glisan about this on the show when we had him on recently, I know from talking to people just generally that there is some element of fatigue with weather warnings. What would be your message to people and to what degree they should give very serious thought to when they receive these alerts?

Dubberke: So, I think the important thing is to be intentional about it and not just assume that you're going to get alerts. That applies to sirens, it applies to your apps on your cell phone. I would encourage everyone to sign up for Alert Iowa. Most counties in the state of Iowa have access to a system where they can go in for their county, for their state parks, for anywhere that they are, you can sign up for where your family is, you can get alerts and be intentional about that. You asked about vulnerability earlier and I think one vulnerability we have is people still when they go to sleep, if you're depending on your cell phone to alert you but you turn it off or turn the volume down at night, then it's not going to do that functionality. So, just encouraging people to really be intentional about that is very important. Nobody wants to be woken up all the time for things that are maybe not impactful. If you live on the top of the hill maybe flash flooding isn't a big concern. So, you would want to take tornado warnings and other things seriously. And it's easy to lose track and get busy during the end of the week and you check the forecast on Thursday and everything is great, you go camping and then you're out over the weekend and all of a sudden something has changed in three days. So, just that alertness and awareness. We have so much information available and so just use that information to protect yourselves. No one is going to come and tap on your door and hold your hand, so we have to kind of do that for ourselves.

Masters: I want to stay with technology here and a brief preamble. So, every morning I host Morning Edition for Iowa Public Radio and as sure as that alarm going off at 4am is going to come, I know that the National Weather Service is going to have my statewide forecast and that's how I kind of structure my breaks and I talk about them. When there's a major weather event whether it be a blizzard or severe thunderstorms I know that there's somebody on that media line that I can call and have them explain it for our listeners. Sometimes Brad, I think I'm talking to you early in the morning. But I'm curious with the rise in artificial intelligence, because that is something that has changed a lot that we're talking a lot about in the news and how that is affecting different professions, is there always going to be somebody there that I can talk to in the morning? Is this going to really impact the way that you do your jobs? Is it doing that now? Brad?

Small: Yeah, it's already doing it now to some degree. There will always be somebody there. There's always at least two people at the Weather Service 24/7 so that's not going to change. But there are some, Colorado state has done some machine learning development on severe weather and flood forecasting. So, that is getting into meteorology and the science right now and that will become more prevalent as we go through time of course. So, it will be leveraged in the coming years certainly, yeah.

Masters: So, there will still be interaction between humans and the way that AI is impacting our day-to-day lives?

Small: Yeah, we'll still be there to interpret it. It doesn't just run and spill out and it's a done deal because there's always pluses and minuses with that, you can look at it and go, well that doesn't really look right, we need to temper that down or that doesn't look hot enough, we need to raise the bar a little bit more. So, it's just one of our tools that we use among all the models and other guidance that we have.

Masters: Donna, anything to add to that?

Dubberke: Yeah, people just, I don't foresee in the near future at all any way that people are going to be out of the forecasting process entirely. The science just isn't quite there yet. Certainly, we love technology, we love it all, it's great. But you still need the person to interpret and to help make sure that the communication happens.

Henderson: There are red flag warnings now that we get in Iowa and earlier this spring we saw 3,200 acres in northwest Iowa burn up because it was just so dry and the conditions led to a field burn. Brad, is that going to slowly keep moving across Central Iowa? What are the conditions that lead to this kind of calamity?

Small: Yeah, we're kind of getting out of that season. It's mainly when the grasses are dormant, the vegetation is dormant, it's kind of the transition season. So, it's the worst when --

Dubberke: Spring and fall.

Small: Yeah, the vegetation hasn't matured yet but the temperatures have warmed up and it's usually windy during the spring and the fall. So, really we're looking for windy conditions, warm conditions and dry conditions, low relative humidities, that's when fire conditions, fire weather conditions are much more conducive or elevated for these fires to spread and develop.

Henderson: Erin?

Murphy: Weather generally moves from west to east and I know, based on my limited knowledge from talking to folks like yourself, is that sometimes we can project what might be coming our way based on what has happened in other areas of the country, for example, whether we're in an El Nino or a La Nina. Right now there's, as I understand, a lot of snow in the Sierra Nevadas. What I'm setting up here is, what's going on out west right now that you all are seeing that could inform what might be coming our way down the road? Donna, we'll start with you on this one.

Dubberke: Yeah, so we're in a transition. You mentioned El Nino, La Nina. We're in a transition now. What has been a little unusual the past three years in a row we've been in a La Nina. And so the length of that is a little bit unusual. We're transitioning now into an El Nino for the coming summer. The signals for us are not particularly strong with El Nino in terms of whether it would be above or below normal. Different parts of the country have different signals related to that. And our signals are not particularly strong. So, we'll have to see what actually happens. But that has been the biggest change that I've noticed in the bigger pattern.

Henderson: Clay?

Masters: We've heard from climate scientists that the climate is more volatile today than it has been in the past, affects everything from air and water quality to public safety to the planting season. How has the change in climate affected your job? Donna, we'll start with you.

Dubberke: Yeah, climate change is a big question. We're in the weather business so we're in the actual what people experience. But climate plays into things like drought that we talked about earlier and certainly plays a role there. So, on our daily jobs not as much, although we talk about flooding, we've got to look at what has the climate been and what are the trends in looking ahead. In the preparedness piece we do a lot of work in working with local communities on preparedness initiatives. And so that plays a factor when you're trying to figure out what should we prepare for if there's going to be more extremes? The derecho question, it's all kind of rolled into that larger picture when you're doing long-term planning.

Masters: Brad, how would you come at that question?

Small: Yeah, I think it's just the same thing. As a meteorologist one of the things we use is climatology, like if I'm trying to forecast even a daily temperature, it's like it's December and I'm going to forecast 80 degrees. But it's like, well wait a minute, that doesn't happen in December. So, it seems like we've kind of had to maybe not trust the climatology aspect as much and anticipate the extremes more. Like the December derecho we talked about, it's like I've got to think twice about forecasting a derecho in December, but the data and the science kept saying nope, this is going to happen, this is going to happen and we kept promoting it and unfortunately it came to fruition. But it's things like that you've got to anticipate better now.

Henderson: One of the ways that you predict things is you have people on the ground, storm spotters. How does that play into it? And do you have enough of them, Donna?

Dubberke: Well, we're scientists so we would say there's never enough data. That's normal for us. Storm spotters are really important because they fill in some of the gaps. So, it's ground truth and it lets us in real time calibrate what we're seeing with the technology to what's actually occurring. So, storm spotters, we also have people who take observations for us, rainfall observations and use known and trusted equipment to do that voluntarily. So, these volunteer networks are very important to what we do.

Murphy: Brad, we've got about a minute left, maybe not quite. In that time, we've talked about technology changing throughout the time, in the time that you have been on this job kind of sum up for us if you could how much technology has changed and changed the way you do your job.

Small: Well, I've been here since the '90s and you would do a forecast, you got like five pieces of information in the atmosphere, you could look through it in 15 minutes and come up with a forecast. And now there's dozens of models to look at and you're just buried in hundreds of items of data and you've got to spend your time kind of saying okay, I'm expecting flooding on this day so I've got this basket of flood tools to look at. So, in some ways it's a blessing, in some ways it's a curse because you've got so many things to look at now with high resolution models that we never dreamed of having and all those models producing fields that we never really dreamed of seeing either. So, it's a big change over the past few decades.

Henderson: Well, thank you both for being here and talking about the weather. I wish you fair weather, both of you.

Dubberke: Thank you, thanks a lot.

Small: Thank you.

Henderson: Thanks for watching this episode of Iowa Press. You can watch every episode online at For everyone here at Iowa PBS, thanks for watching.


Funding for Iowa Press was provided by Friends, the Iowa PBS Foundation.

The Associated General Contractors of Iowa, the public's partner in building Iowa's highway, bridge and municipal utility infrastructure.

Elite Casino Resorts is rooted in Iowa. Elite's 1,600 employees are our company's greatest asset. A family-run business, Elite supports volunteerism, encourages promotions from within and shares profits with our employees.

Across Iowa, hundreds of neighborhood banks strive to serve their communities, provide jobs and help local businesses. Iowa Banks are proud to back the life you build. Learn more at