Showers and thunderstorms are still expected to move into the region later this afternoon and evening with a developing low pressure system traveling through Ohio. The latest severe weather outlook has shifted the threat a little more South than that at this time yesterday.
It has likely been shifted South for a couple of reasons..
1) Most of the region has been under overcast conditions so far today. This is good because a lack of sunshine will allow the atmosphere to remain a little more stable than if it was sunny all day. Sunshine only helps to amplify the development of storms thanks to a warmer atmosphere. Here is a look at CAPE values later this afternoon around 5 PM. You will notice the CAPE really isn’t that high (high values are usually above 2,000 j/kg) This is very much due to mostly cloudy skies and not a lot of sun. Again, CAPE measures the atmospheres ability to produce rapidly developing storms.
2) The area of low pressure that will strengthen later tonight looks like it will track right across WC Ohio. This is both good and bad. It’s good because it won’t allow the area to warm up very much, areas South and East of the low are always targeted for the best chance of severe weather because of better warming. Here is the location of the low around 8 PM over Central Indiana, it is expected to generally follow the front to the East of it and track through WC Ohio.
It’s potentially bad because anytime a strengthening low moves directly overhead there is more of a chance for rotating storms. While the biggest threat continues to be damaging winds, there is the possibility for an isolated tornado as well. The national weather service reflects this concern over NW and Northern Ohio where the low will track noting a very slight chance for the development of a tornado in the region.
As far as a time frame is concerned, expect the storms to move in during the late afternoon and continue to be a threat well into the late evening hours. I’m keeping a close eye on it!