support comes from St Louis Public Library Foundation helping the library serve children and their families with programs and services needed to become lifelong readers more information about the foundation is at slpl.org this is St Louis on the air from St Louis Public [Music] Radio I'm elain Chaw there was a a cooler July sort of sound sandwich even in no till systems no till kind of conservation agriculture systems where people aren't tearing or ripping the soil we can still get windblown erosion because of planting or other types of equipment that's running through the field it is summer it is supposed to be hot it is supposed to be humid um but we don't warn people unnecessarily at night that's when the effect of humidity is really elevated [Music] the St Louis area has a welld deserved reputation for hot muggy Summers and finally our weather apps and let's be frank our bodies are telling us temps are cooling down so we can relax at least until next summer right well the answer is both yes and no and here to tell us why we've got two field experts first we welcome Matt by ER lead meteorologist with the National Weather Service St Louis great to have you back thank you very much elen and we're happy to welcome Trent Ford Illinois State climatologist Trent thanks so much for making time for us today yeah great to be on a lane so Matt let's start with you as we said in the intro temperatures are finally coming down but not long ago we had a lot of really hot summer days was that normal for our region so what's defined as normal seems to be changing itself as well so um we we take a look at normal for summer um as hot muggy right but even over the course of the last 30 40 50 years we're seeing that Baseline what we consider to be normal um change slightly and I don't think it's perceptible changes you know the body human body can't take um you know a couple of degrees and notice that um but we are seeing a gradually increase in what normal is this summer in particular exceeded those normals in terms of temperature and precipitation in different ways so um overall it was a slightly warmer than normal summer and we consider summer just to make it easy on ourselves June July and August just just to do that um however it's if you look at that it doesn't tell the whole story June and August were much warmer than normal a couple degrees above normal with several inches below normal precipitation so we weren't getting a lot of rain in St Louis and we were a little bit warmer than normal which kind of exacerbates that situation but July was kind of a reprieve we were near normal um we had quite a bit of rain in St Louis so it kind of evened us out a little bit it really didn't even even us out totally uh we were a little bit below normal in terms of rain but and and a little bit warmer than normal in terms of temperature but it's those oscillations month to Monon even dayto day that are concerning um for for everyday life right and do those oscillations also then contribute to our feeling like there is such a big difference there is a a cooler July sort of Sandwich happening um it it it might you know I think that the the ability for us to um to string together all those different um those different extremes and keep in mind that it's still summer is a little bit is a little bit difficult um because you know we're kind of it's a recency bias we're just trying to REM oh yeah it's it was hot back in June so this stretch of nicer weather or actually below normal weather um it is kind of strange for you know summer in St Louis um and some are in the midwest it wasn't in just St Louis the Midwest was actually relatively normal if not slightly below normal with in terms of temperatures in July so it's difficult to to string those together Trend something I I I want to ask you about is a a term that was sort of trending a few weeks ago started popping up all over the Midwest and that's corn sweat so what exactly is corn sweat yeah you know what's funny th this every year around July and then it kind of keeps going through the summer I I hear about corn sweat and get questions about it this year it exploded I'm not exactly sure why that is but it definitely was very popular not just in the midwest but nationally corn sweat actually is just kind of a colloquial term for something we called transpiration which is when uh the corn plant in this particular instance but really most plants do this they have little holes in the bottom of their their leaves called stamata they take up water through their roots and they open up their stamata and their leaves to let in carbon to let in uh light for energy and there's a little bit of water that's released and it's evaporated into the air um and the amount of transpiration that an individual plant gives off is pretty small uh maximally a corn plant will give off maybe 3/10 of an inch uh at the very maximum during silking stage kind of mid July um but if you multiply that by all the plants we have not just corn but all the plants we have across just the St Louis area alone uh let alone all the Missouri and Illinois uh it adds up to quite a bit of of moisture and so um it's doing this all the time whenever the plant is actively um actively respirating the the the issue is that we really hear about corn sweat most when we have high humidity and that's when people start to think about well how much this humidity is because there's so much corn out there right uh and so that's kind of where it comes up and in reality it's kind of the the the the agricultural landscape that dominates much of Illinois and Missouri does contribute a significant amount of moisture for humidity but in general from the studies that have been done it it's less than what is being blown in from other areas like the Gulf of Mexico MH so corn then is not the the prime culprit in in what we're feeling so in in terms of what you're saying about what is being blown in from the Gulf how is that contributing to our humid days and and hot nights yeah so the humidity is uh a really important factor when I think about the effect of heat on on human and animal health so the reason being is that you know our bodies have evolved to deal with heat and hot conditions by by sweating um our sweat and that sweat is evaporated and that cools our skin temperature but you know something that gets lost in this corn sweat discussion too is the the fact that we as humans and the corn can can can transpire or sweat as much as we want but if that atmosphere is really that air is really really humid it's not going to take in very much more and moisture and that's where that that uh that humidity really plays a role that if we get that not just hot air but very humid air blowing in or what we call advecting in from the Gulf in other regions uh it makes our sweating less effective at cooling down our bodies so during the day those hot and humid conditions are much more dangerous than than the conditions that are at the same temperature but drier and that's really why the National Weather Service and others use the heat index which combines the effect of heat and humidity but as you mentioned at night that's when the effect of humidity is really elevated and and this is something that you know during the summer and even this time of the year we often kind of gravitate towards the big eye popping high temperatures like I got to 103 in St Louis today but in reality that humidity plays an even larger effect at night when we may only get down to 80 82 83 degrees and that adds to the stress that that heat really adds to humans MH so with humidity that is moisture and Matt you had mentioned that we did not get as much precipitation as uh we would in other years but there was also some extreme rain and in July floods caused a dam to nearly fail in Nashville Illinois and we actually had our environment reporter Kate grumpy and uh Brian Muno out there to take photos and video was that sort of precipitation unusual for that area of Nashville Illinois I wouldn't say it's unusual for that area just because um while they got quite a bit of rain 5 to 7 in of rain in a very short period of time that's not uncommon for the summer what is unfortunate is that it that again that rain fell on over a very short period of time over the same area so in a combination of rain repeated rounds of thunderstorms going over and over and over one specific area um and we even saw some of that in St Louis not to nearly as much extent as Nashville did but um but you know same thunderstorms over rounds of thunderstorms over and over again and what we call High efficiency rainfall so um you talk about humidity at the surface or near the surface I'm now I'm talking about humidity throughout the entire atmosphere if you think of the atmosphere as kind of a column right above your head um there's high humidity through that whole atmosphere there's less opportunity for all that moisture to come out of the air if it's really saturated so if that's the case that combined with that those repeated rounds of thunderstorms is just a it's really a worst case scenario um those systems are not uncommon in the summer but they aren't you know they're not run-of thee Mill thunderstorms these are and these are things that we are um we are expected to see more of uh these extreme top 1% of of his historic um rainfall type type of events are becoming more common in the midwest according to the National Climate assessment um and to T touch on something that Trent said about overnight lows and and humidity as well that is a really under I think an under reported or an under under discussed aspect of heat stress um on in June of this year in particular on average we had 3 and a half degre uh warmer lows than we would normally have so we're not getting that reprieve during the day in addition to the humidity um or excuse me we're not getting the reprieve of temperatures at night in addition to the humidity that St that sticks around overnight um for folks that don't have air conditioning don't have means to to relieve themselves of the heat and humidity it's a it's an it's an unbalanced stress you know we have the the the opportunity of of going to our air conditioned apartments or houses not everybody in the St Louis region has that ability we're going to take a quick break but we'll be back very shortly to continue this conversation this is St Louis on the air and St Louis Public Radio if you have a smart speaker you have access to the entire world world of NPR and St Louis Public Radio all the latest news and all the captivating stories activate our voices with yours by telling your smart speaker to play St Louis Public Radio let's return to our conversation about extreme weather particularly heat and wet and why certain folks are at risk during emergency weather situations talking with us about these topics we have Trent Ford Illinois State climatologist and M Matt by lead meteorologist with the National Weather Service St Louis before the break we were talking about rain and I'd like to hear Matt from you about the the effect the long-term effects that rain have on people um and the kinds of things that we need to sort of be thinking about uh when it comes to precipitation and how this affects our living environment yeah rain is rain's funny because you need you need a decent amount of it but you don't want too much you don't want too little it's kind of a gold a Goldilocks effect so in terms of too much rain I I think that that might be the easier way to start um too much rain can result in flooding flooding results in injury and death as a matter of fact it's the number two killer in the United States in terms of weather related uh fatalities behind Heat so we're talking about the top two um and it's a it's a it's a un un it's a silent killer right and it's it's uh sociological Studies have been done as to why that is why does why does flooding kill people and it's mainly because people don't expect it to be that bad they will put themselves into situations and unfortunately has several fatalities in the s i I'll use this by state area even as far out as Columbia Missouri um this year where people either drove into flooded Waters or something which is even sadder people First Responders are saving people from flood waters and then they themselves pass away because of the flood waters so there's that there's um the potential for increased waterborne disease and then economic loss in Social dis social displacement if you've got people who are maybe lower middle class or just barely above the poverty line living in a home or in some sort of dwelling and that dwelling gets flooded and they don't have the proper insurance that significantly changes their living conditions um and then on the opposite side side of things if you don't have enough then we have agricultural problems and I know Trent can speak to this to a probably with a lot more fluency but you know drought is a huge crippling um problem in the midwest we are the sort of bread basket of of America and parts of the world and um we we provide quite a bit of resources to the rest of the world and the United States itself so not having that rain um is certainly a detriment to the agric agriculture uh agricultural Community but Al um shipping and navigation on the on the main stem Rivers so lots of stuff that that could go wrong either way so Trent you were called on uh by Matt here and there is a a drought index report that actually came out this morning what are the numbers there and what do they tell us yeah so this is the drought the US drought monitor which is released weekly um and it's sort of the gold standard for Drought monitoring across the United States um and what it's showing is that across the Midwest generally but particularly in the mid Mississippi Valley we're seeing an expansion of drought because of the conditions that Matt talked about earlier about how dry August was despite the wetness in July uh and how dry this the start of September has been so as of this latest map which is by the way is current as of Tuesday so it was released today current as of Tuesday um roughly 44% of the St Louis weather forecast area which stretches from Columbia to you know call it Mount Vernon Illinois is uh is in moderate drought and a small Corner uh in the very southeast part of the region is in severe drought what we call D2 so it's worse as you go south towards Cape dardo and even worse in the boot heel um but this is something that we've seen is sort of like a a regional expansion of broader drought that's affected the Lower Mississippi Valley and Ohio valleys for the last month or so mhm you know we're a little over a year out trend from a deadly dust storm that happened uh and led to zero visibility conditions on Interstate 55 in Illinois seven people died and 37 others were injured in a crash of 72 vehicles I mean how rare is an event like that and you to what extent is is drought the problem or are we misunderstanding or misapprehend if we're only thinking about drought and not about precipitation which we may think of as being the the flip side yeah you know it's interesting with the dust storm because we are the largely misunderstanding the issues at hand there but it actually is not even the flip side of precipitation something a bit different but I'll get to that in a second so what happened in the with the dust storm last year um it it is yes and no it's a rare event it's an event that uh we don't necessarily have great records of dust storms in the midwest like they do out west because it's much less of a frequent Hazard but it's a hazard nonetheless so what we have to do is kind of stitch together reports from the National Weather Service from newspapers going back and so what we see is that really significant dust storms like what we saw last year along I55 happen maybe once every four or five years across um at least across Illinois um and uh what we see is that they typically happen that time of the year between April and June and that is when we're typically the windiest climatologically but we also have a lot of Land Management and people working the soil which can stir up and increase the the wind erosion rates and that's really where a lot of the what happened last year is sort of misunderstood the weather conditions that that created that dust storm that stirred up the dust were extreme yes the winds were were sustained 25 to 45 mph gusts up to maybe 60 MPH across that region but it's not necessarily super rare certainly not unprecedented to have strong winds also because it was pretty dry to start April that year uh the top soil was pretty dry but the but below four or five inches deep it was actually pretty wet still um the the biggest issue with that dust storm is really the Land Management aspect of it and if you go to that part of the state what we have is a large tracks of land that is actively managed actively farmed without wind breaks uh and so that time of the year even in no till systems no till kind of conservation agriculture systems where people aren't tearing or ripping the soil we can still get windblown erosion because of planting or other types of equipment that's running through the field um and so it is a situation where when we understand the weather conditions it's very likely we'll see weather conditions like that again not maybe not next year maybe not the year after uh but but certainly those windy conditions again weren't unprecedented and so it's really I think what that what that that Hazard or what that um tragedy really kind of put in perspective is how are we managing the land in in in kind of concert or maybe not in concert with the the weather hazards that we experience and what can we do as far as a Land Management aspect to make sure that if we do get those winds again we do have some slightly drier soils that we can um reduce the the risk of of having that windblown uh soil you know blowing across a major Interstate right um Matt as we're wrapping up here you know part of the role that you play at the National Weather Service is making sure people have the information they need to stay safe in extreme weather events what have been some of the challenges that have existed with warning people about such events this summer I think um I think the challenges are different depending on what hazard you're talking about it's a it's but it's complex and I appreciate you bringing it up um so for heat um the biggest complaint we hear is it's summer it's supposed to be that hot but people I think are thinking themselves in their air conditioned homes not people working on streets or people um who don't have the ability to cool down um people that are in our community that they may not be thinking of those folks that is who we're here to serve we're serving every single person in the St Louis region not just the folks that have the ability to cool down and yes it is hot it is supposed to it is summer it is supposed to be hot it is supposed to be humid um but we don't warn people unnecessarily you know we're we we have set thresholds for a reason so I think that for heat that's our probably our biggest concern that and the the longevity of things um explaining to people that a day of 100 degree heat index is not that bad but five days of it straight is pretty gnarly and we don't want to we we we want people to take those precautions because that's a really slow creep that Hazard and then for rain in the uh in the in this part of in this season in summer the biggest problem we have is we we sometimes we have pretty good skill about when we expect Heavy Rain excessive rain flooding to occur it's the where and exactly exactly when right so explaining to people in this area you know maybe in this 60 Mile Stretch we have the high potential of you know heavy rain and flash flooding people want exact numbers exact locations and truthfully we can't give it to them we just ask people to be prepared and take appropriate action when flooding strikes um but that's the biggest challenge there and I think one other challenge that perv that kind of threads through all of that is not everybody gets that information the same way right right Matt berer is lead meteorologist with the National Weather Service St Louis and Trent Ford is Illinois state climatologist Trent and Matt thank you so much for talking with us today thank you elain thanks [Music] elain today's segment was produced by AA kzit audio engine enging and podcast design by Aaron door our executive producer is Alex Hoyer St Louis on the air is a production of St Louis Public [Music] Radio understanding starts here do you find yourself regularly listening to episodes of St Louis on the air suggest us to a friend you think might enjoy our conversations and leave us a review and rating on Apple podcast on the app store it's the simplest way to help people discover our show thank you St Louis Public Radio is a member supported service of the University of Missouri St Louis the Gateway brings you the day's news each weekday from around the St Louis region and the state capitals in Jefferson City our schools are accredited we don't need this bill and Springfield how many more years must pass before lawmakers see time is of the essence I'm Abby Loro join me each weekday for the Gateway on the stlpr app or wherever you get podcasts [Music]