Intense thunderstorms will continue to impact the Fox6 viewing area through at lest 7pm. These storms are packing a serious punch. While not reaching the threshold for a severe thunderstorm, we have seen at least a dozen reports of nickel to quarter size hail in Jefferson and Shelby Counties as well as downed trees. This is a picture the Vestavia Hills Fire Department.
A tree fell on a car on Broadway Street. A woman and four children were in the car. There escaped injury. We have another report of a tree on a house in Homewood this afternoon.
The NWS definition for a severe thunderstorms is 58mph winds and/or 1" hail. These storms have been just beneath that threshold, but still able to do some damage. The CAPE or Convectively Available Potential Energy is between 2500 and 3500 j/kg this afternoon. The LI or Lifted Index is between -7 and -8. Those number allow for explosive thunderstorm development and strong updrafts. We've seen significant hail from those strong updrafts.
Fortunately, there is practically no wind shear in the atmosphere and that is limiting any tornado potential. In fact, the winds are so light aloft - the storms are moving very slowing and have formed a line across the state slowing building and filling in the caps this afternoon.
The storms formed earlier this afternoon along a convergence zone near the I-20 corridor and are drifting slowing to the east. Rainfall has been falling at a rate of 2-3" per hour based on radar estimates. We can expect some localized flooding in parts of the Jefferson County. The storms have been producing intense cloud to ground lightning.
While the thunderstorm chances are fairly low tomorrow, it's still possible we could see a few thunderstorms Saturday afternoon similar in strength. The high temperatures are one of the key ingredients for instability resulting in intense thunderstorms. The primary threats with any thunderstorms this time of year is powerful cloud to ground lightning. Please remain weather aware and make sure you take the weather with you using our WBRC weather app. The app can be a lifesaver - especially the lightning detection feature.
Stay with Fox6 and Fred Hunter tonight for updates.
Fox6 Chief Meteorologist