Rain Chances Increasing this Afternoon & Evening
Tropical Storm Isaac is still holding on this morning, and while the maximum sustained winds have decreased to 40 MPH, there is still a threat of some heavy rain and severe storms mainly in Mississippi and the western edge of Alabama as far north as Hamilton this afternoon and evening. The majority of the Tennessee Valley will just see a cloudy sky, a southeast breeze, and some occasional light showers throughout the day. The chance of any one spot getting rain is about 30% today and 40% on Friday. There’s a lot more specific forecast information through the weekend on WHNT.com Weather!
For high school football games tonight, there is a slightly better chance of a shower or storm west of I-65 in North Alabama; while showers are possible over the eastern sections of the state this afternoon, we do not expect them to be as widespread. Take an umbrella or poncho just in case you’re the unlucky one that happens to get a downpour.
The increased threat of rain is due to some stronger winds in the middle and upper atmosphere ejecting northeast away from Isaac’s center. Sometimes we refer to this as a “disturbance” or “area of disturbed weather,” but in this case, it’s simply stronger winds at 10,000 to 20,000 feet off the ground that are enhancing showers and storms.
There is some surface-based instability (CAPE) for storms to feed on today, but we do not believe there will be a significant risk of severe storms in North Alabama or Southern Middle Tennessee today. The dynamics enhancing the storms to our southwest today will be a little closer on Friday, and that means a very small threat of some strong or severe storms over the northwestern parts of Alabama through early Friday afternoon. Like I said last night, there’s no reason to get too worried about this. Go about your business like you normally would, but stay connected just in case an isolated storm or two gets out of hand.