NORMAN, OK — A day that started as an epic bust/lack of a storm chase turned out to be anything but disappointing. It was an event that nobody could have predicted (not even the models), featuring golf ball sized hail and freezing rain falling out of a severe thunderstorm at the same time, enhanced severe storms behind an incredibly strong cold front, and a significant (and very rare) April ice storm.
The front itself was one of the strongest I’ve ever seen. The temperature gradient was impressive, with temps in the mid-70’s in Paul’s Valley, and temps were in the mid-40’s in Oklahoma City, about 40 miles away. Apparent temps (heat index/wind chill) ranged from the low 80’s in southeast Oklahoma to near zero in the panhandle.
One amazing feature of this front was that it was quite shallow for such a powerful front, extending only about 1 km or so up into the atmosphere. With the large amount of instability on the warm side of the front, this created a very unique setup, as the atmosphere retained its large instability aloft behind the front despite surface temperatures in the 20s and 30s. As a result, a line of severe thunderstorms broke out across northwest Oklahoma. The town of Arnett witnessed golf ball sized hail and freezing rain falling out of a severe thunderstorm at the same time, with a surface temperature of 27°F.
Then there was the ice storm. It was one of the most severe ice storms to ever hit Oklahoma in the month of April. It is extremely rare to get ice storms in Oklahoma in April, much less one of this severity. Western and northwestern Oklahoma got hit the hardest, with ice accumulations as high as half an inch in places. Parts of Norman reported a very light glazing of ice, but I did not see anything either at the house or while I was out driving around that morning.
When it was all said and done, many locations across Oklahoma experienced a 24-hour temperature drop between 40 and 60 degrees. It was an impressive consolation prize for the lack of severe weather (thanks to the pesky cap).It is an extraordinary event I will remember for a while, too.