Winds will be out of the south and gusting to 30 mph this afternoon. That will lead to an unseasonably warm afternoon, and set the stage for strong-to-severe storms late in the day.
By the mid afternoon, isolated to scattered storms should develop. This activity won't be as widespread across the area as the line of storms later, but the storms that do form could produce locally heavy rainfall, damaging wind gusts, and frequent lightning. An isolated tornado is also possible given the wind shear in place.
The line of storms will still be to our west late this afternoon. The line will begin to make its way into the Valley this evening. It will slowly work eastward through the Valley overnight. It's along this line where we'll see the highest chance for more widespread severe weather. Wind gusts to 70 mph and brief, spin-up tornadoes are the main threats.
The threat for severe weather in the Shoals starts to ramp up after 8pm. That's when the leading edge of the storm line moves into the area. But, stronger storms are possible as early as this afternoon ahead of the main line.
The line shifts into the HSV metro area within 1-2 hours of midnight...so that's when the threat for more widespread severe increases. Frequent lightning and heavy rain can be expected with these storms as well. The severe threat diminishes Tuesday morning by sunrise as the line shifts into northeastern Alabama.
The line of storms should be less intense when it makes into northeastern Alabama, but a few stronger storms are still possible. The threat for severe weather will be highest just before dawn and into the morning hours.
Because this storm line should be slowing down across the Valley, flash flooding may become a problem for Tuesday morning...especially to the east of I-65. Give yourself extra time to get to work Tuesday morning as flooding could be ongoing and there may be downed trees and power lines that slow you down as well.
If you have a weather radio, make sure it's working and has fresh batteries. You may want to download the WAFF weather app to your phone or tablet. We will stream our weather coverage on that app starting this evening and continuing through the night until the severe threat is over. It can also alert you with push notification when warnings are issued. You can watch our coverage even if your house loses power.
Stay with the 48 Storm Team as these storms near the Valley tonight.
-Meteorologist David Ernst