This interview was edited for brevity and clarity.
Bill Burton: It's time for us to take a look at the Science Behind the Forecast, as I am joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.
TA: Good morning. With all the heavy rainfall that we've seen lately, I figured, let's talk about that.
BB: Yeah, we've had just a little bit of rain throughout the area, so that is our topic today and the frequency of heavy rain that we get. Tell us about it.
TA: So Looking into the data, I've found that Kentucky has, of course, everybody knows this, it has experienced a significant amount of flooding over the last decade, and that has been mainly due to heavy rainfall events. So looking into all the numbers over the last 60 years, every single part of the United States has witnessed an increase in the number of heavy rainfall events,
BB: Every part?
TA: Every single part of the U.S., but we've seen that more in parts of the Midwest, the Northeast, and the Southeast. And by the way, that does include hurricanes and tropical systems. So when you look into things, for every single degree Fahrenheit increase in temperature that we have, the atmosphere can hold 4% more moisture. This means that on those warmer days with those warmer temperatures, that can contribute to heavier rainfall, which can result in flash flooding. And of course river flooding like we have seen recently in the past couple of weeks. So the research analyzed hourly rainfall intensity data from 144 weather stations across the entire US and it looked at the years between 1970 and 2024. And of all of these locations, of the 144 locations, 88% reported an increase in hourly rainfall rates of more than 15%.
BB: 88%. That's staggering.
TA: That's an incredible amount of rainfall across the country that we're seeing. So the greatest increases we're seeing in the upper Midwest, that's where there was an 18% increase in heavier rainfall, in the Northern Rockies, that's where there was a 16% increase, and of course, the Ohio Valley, where there was a 15% increase. So the The numbers are backing up what we are unfortunately seeing across our area.
BB: Tragically.
TA: Very tragically. And by the way, these increased rainfall rates were recorded in a range of locations. So in parts of the desert southwest, towards subtropical Florida, all the way towards Maine, all of these spots saw some sort of increase in heavier rainfall, and specifically in Louisville, between 1970 and 2024, we saw a 26% increase in rainfall intensity.
BB: Wow, that's a little too much.
TA: That's way too much. And researchers found that counties in Kentucky specifically, Tennessee, Georgia, Alabama, Mississippi, North Carolina, and Maine were the most likely to experience at least a 30% increase in extreme precipitation. And that does mean heavier rainfall and of course droughts as well. It does cover both of those. But notably, this increase was not linked to areas with the highest overall rainfall totals. So just because areas had a lot of rain doesn't mean that they were seeing a lot of heavier rainfall, to be very specific. So extreme precipitation events, whether that's flooding or droughts, those are expected to become, unfortunately, increasingly more common worldwide, so more of the heavy rain, more of the flooding will be part of our day to day life.
BB: Yes, definitely not good news that we have a higher likelihood of having more heavier rain events, but at least now we have a better understanding as to why, thanks to this edition of Science Behind the Forecast with WAVE 3 meteorologist Tawana Andrew. Thanks for the knowledge, Tawana.
TA: Of course.
