This is one of the more difficult severe weather forecasts we've had. For example, April 27th, 2011 was an easy forecast with horrible results. We knew with little exception there was going to be devastating tornadoes. First of all, let's get the record straight - this is not a repeat of that historic outbreak and the forecast is far from cut and dry.
Potential is the key word regarding Wednesday's forecast. We have the "potential" for some extreme weather because of the impressive amount of instability being forecast by the models. The shear is rather modest - especially at the time of the most instability during the afternoon. It's impossible to tell you exactly where a tornado will strike until it forms. In fact, we don't know if any tornadoes will form. We do know the key ingredients for tornadoes, large hail, and, damaging winds will be available tomorrow and that's the reason for concern.
Let's break Wednesday into two separate rounds.
Round one: We will see thunderstorms moving into areas south of I-20 between 5am and 6am thanks to a warm front lifting northward. I think the storms will be elevated at first with gusty winds and hail as the main threats. But, the storms will likely become more surface based through the morning. This will mean a better chance for tornadoes. Models continue to indicate the highest potential for these storms to become severe is south of I-20 and east of I-65. This gives you a general idea on at least the most likely areas for severe weather during the morning. Important note: severe storms will not be localized to one area. If you're in West Alabama severe weather is possible, the chances are just a bit lower. Storms and rain will likely continue through at least noon.
Round two: This is the even more complicated forecast. My experience as a meteorologist tells me we'll likely see a pre-frontal squall line setup ahead of the cold front moving west to east across the state. The instability values are extreme and this means these storms could produce golfball size hail and damaging winds. Tornadoes are still possible during the afternoon. Keep in mind much of what happens in the afternoon is conditional on the morning thunderstorms.
Storms will clear the area by 7pm and we will be looking at sharply cooler temperatures with clearing skies. Overnight lows into Thursday will fall into the upper 40s.
It's possible the main event with this severe weather could be in Georgia and not Alabama. As we like to say, please remain weather aware and have multiple ways to receive severe weather updates including the WBRC First Alert Weather app.
See you in the AM!
WBRC First Alert Chief Meteorologist