Unfortunately, no big changes in the forecast for today. The new Day 1 SPC outlook is out and they continue a moderate risk over our area. I wouldn't be completely shocked if we saw a small area in east Mississippi into Alabama upgraded to a high risk, depending on how things play out. Still seems to be likely there will be numerous supercell storms out there this afternoon with each one having a chance of producing a strong tornado.
The graphic below (click it to make it bigger) has three windows. The top left window is the outlook from the SPC. The area outlined by the red line is the moderate risk area. It covers about three-fourths of Mississippi and just about all of Alabama. I don't show it here, but within than moderate risk area is a 15% chance of strong tornadoes within 25 miles of a point. Strong tornadoes are those EF-2 or higher. Back to the graphic....the bottom-left screen shows surface dewpoints at 4PM. You will hear many people call the surface feature moving in a cold front. Well, there will be a cold front that eventually moves through, but the surface feature that will aid in storm development is called a dry line. The dry line is a feature that is very common in the Plains, especially Oklahoma and Texas. Like a cold front, the dry line is boundary. It separates warm, humid air to the right of the dry line from hot, dry (less humid) air to the left of it. Normally the dry line does not make it this far east, but it will this afternoon. As it combines with our muggy, warm air mass along with strong upper level winds (large screen on graphic), severe storm development is almost certain. Storms and the severe weather threat will end from west to east immediately as the dry line moves across. You should also notice a pretty quick drop off in how humid it feels once it passes.
Unfortunately, I can't get any other model graphics to upload. But let me go ahead and discuss timing. If you live west of the I-55 corridor, your severe weather chances will end by about 2PM. Those areas east of the I-55 corridor will see the risk of severe storms continue into the early evening, but most of the storms will be out of our coverage area by 6PM and the severe weather should be out of Mississippi by 8PM.
Most of the storms we see today will be scattered in nature. This is part of why they will be quite dangerous as they will be out on their own and really be able to take full advantage of the environment they are in. But due to the scattered nature of the storms, some of you won't even see a drop of rain today. I wish it were possible to be able to say that X, Y, and Z counties will for sure have storms, but if that were possible, I would be a rich man. ALL of Mississippi needs to be weather aware today, but especially those areas east of I-55 as those areas will likely have an enhanced risk of significant severe weather due to the best dynamics and features arriving at the time of peak heating.
Please make sure to follow me on Twitter @EricLawWLBT or on Facebook at facebook.com/TVEric as that is where I will be micro-blogging updates. IF I have time later this morning, I may make a quick post on here. As I've been typing this, a Tornado Watch has been issued for much of north and western parts of Mississippi. It goes til 10am, but I'm sure we will see more watches issued further east later this morning.
It is a little after 3AM and I've got to get some rest. Long day ahead!
Be safe today and take all warnings seriously!
Eric - elaw@wlbt.com
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