The atmosphere has been busy over the eastern 2/3 of the country this week with lots of severe weather. Thankfully we have not had to deal with much more than April showers to this point. But that may change today.
Our Thursday started with some rain as the same front that has been bobbing around all week continues to be a trigger for wet weather. It’s easy to find that front this morning by looking at regional temperatures:
Zooming out and taking a look at the country, we have a strong area of low pressure in the Plains and it is moving northeast. As it does so it will drag a warm front in our direction today and temperatures will have little trouble reaching the lower 70s this afternoon. It will even feel humid.
Meanwhile, the juicy air is being transported north by what we call a “low level jet”, a fast-moving river of air that is a few thousand feet above our heads. This isn’t the “jet stream” that we normally think of, which is up at around 30,000 feet. THat low level jet brings the warm, humid air north and can also aid in creating instability in the atmosphere. Here’s the wind at 5,000 feet this afternoon:
Notice the brighter colors (faster winds) just west of our region.
The ingredients are coming together for some big storms. But where? The Storm Prediction Center has the highest risk across the Mississippi and lower Ohio Valleys:
This makes sense, given that that region is closer to the low-level jet, there is more “wind shear” (changing of wind direction and/or speed as you go up through the atmosphere) and generally has a more unstable atmosphere overhead. One measure of instability is CAPE, or Convective Available Potential Energy.While we have a moderate amount of CAPE around the Valley later today, it’s highest to the west.
So, what do we think will happen? There will be a break from the rain during the midday and early afternoon. IF we manage to get some sunshine during that period, it will help make the atmosphere more unstable. A line of showers and thunderstorms looks to push in late this afternoon and evening (roughly 4-7pm). 6pm simulated radar, based off HRRR model:
The odds of severe weather (winds in excess of 58 mph and/or hail 1″ or larger), while highest to the west, are not negligible here…generally in the 5-15% range.
The primary threat will be damaging winds.
We will keep you updated all day on TV and social media. If the situation warrants, we will do live streaming coverage later today on wfmj.com.
Thanks for reading!