re: Severe weather threat continues today for parts of the southeast - Threat is Over.

Nick Mikulas

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I typically want to wait and see the morning run of the models, but I have the time to update now, so I’ll go for it. I have to get out in front of the “real job” work today so I can keep my face buried in radar, or on the road chasing tomorrow. The main idea, as you can see from the upgrade to moderate risk from SPC, is that this will likely be quite the day/night, especially to our east. But as I’ve said in the last couple updates, just because we aren’t in the center of the highest threat doesn’t mean there isn’t a significant local threat for severe weather. But I do worry there could be a potentially significant outbreak of tornadoes to our northeast, and that would be a nighttime outbreak, which makes it even more dangerous. Here’s what I’m seeing locally.

First off, the initial surge of deep moisture will overspread the area today, and along that subtle boundary, we could get a few thunderstorms. There is a marginal risk for severe weather in the northern half of the area, basically north of a Fort Polk to Alexandria to Marksville line. The severe threat should be isolated, but a couple severe storms are possible. Some won’t see rain, some will see a decent storm. Yes, we are getting to that time of year where I get to say partly sunny with a chance of brief chaos. Overnight, I think we calm down as we prep for Wednesday.

Wednesday looks busy, though it should be fairly calm until around noon as storms approach the Texas/Louisiana border. This slightly slower progression means more time to heat up, and prime the atmosphere for storm development. The best chance for severe weather starts around 12:00-1:00 PM Wednesday, and should cross the Mississippi River around 7:00 PM. So it’s a short window of time, but could be a pretty rough one. I’m thinking around 2:00-5:00 PM is our active time here in Rapides Parish, which means temperatures could approach 80 degrees. That will bring us plenty of instability to go along with ample wind shear, and that means that all modes of severe weather are possible. Again, the threat should be more intense, and more widespread to our northeast, but it only takes one bad storm to cause major problems. One slight saving grace down here is that the sea surface temperatures in the Gulf of Mexico are still fairly cool. With strong surface southerly flow blowing over those cooler waters, we could see slightly more stable air in parts of the area. The impact of that should generally be closer to the I-10 corridor, but that could help tamp things down a bit the further south you go.

So our main idea here is that there is a level 2 of 5 threat for all modes of severe weather in our area, especially Wednesday afternoon. It wouldn’t stun me to see this bumped up to level 3, but for our purposes, let’s just plan on a busy afternoon. I know the timing of this will coincide with school pick up for some, so keep an eye on radar, and my obsessive updates to get an idea of what’s happening before you head out for any reason. The last thing you want is to unknowingly drive into a tornado warning. I’ll update things late this afternoon after a couple more model cycles.

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I think South Louisiana will be mostly out of the worst stuff. NE La, Eastern Ar, central Ms to north MS, and Alabama are in for a show

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Have to drive from Memphis to New Orleans tomorrow. What time can I do this to avoid the worst weather?

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There’s really not a time tomorrow where there isn’t some risk of severe weather across Mississippi. At least not until late tomorrow night. It’s hard to say exactly when things will get going and if there will be any lulls in activity.

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I think a good compromise would be to keep the schools open to be shelters, if needed or wanted by the local community

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I agree, I am surprised that they do not offer a local high school or something as an emergency shelter.

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God looked at Mississippi and said, "frick this place in particular."

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Can you really blame him?

Reading the SPC discussion, I started thinking about a comparison between this setup and April 27, 2011. On April 27, every major parameter was off the charts, and every met in the Southeast knew what was going to happen.

With this setup, every single possible parameter is just high/bad enough to come together and give a great chance at high-end severe storms. This is such a messy setup for tomorrow.

The 12z NAM did have a weaker low level jet tomorrow evening than previous runs. Still sufficient for tornadoes, though. I guess we will see if any other models show that.

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Some, but definitely not all,thought early in the day these early AM storms may could calm the air to suppress the storms for later that day.
Obviously, that didn't happen.

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Most hoped it would happen, but knew that if/when the sun came out it was game on. Unfortunately, the sun came out, and there was more than enough energy and instability left to fire those discreet super cells. The storm mode of the morning being a QLCS with the storms moving 60+ mph meant that most of the storms and clouds were through MS and Western AL nearly by daylight on the 27th. Nothing was behind the line to provide cloud cover, and the sun started shining almost immediately.

One saving grace tomorrow may just be the messy setup and multiple waves with patches of storms that could linger. Anything that hangs around to the south hopefully will serve to cut off that crazy southerly flow to the North. Of course, that does nothing to help places further South.

I actually think the Moderate risk area isn't broad enough. There is plenty enough SBCAPE in Southwest/Southern MS along with some healthy looking Helicity/Updraft. I haven't gotten a great look at the shear down that way, but I'm assuming it looks similar to the rest of MS and AL. Any storms that get going down that way will also go severe almost immediately.

We should be getting a new day 2 outlook for tomorrow from SPC around 12:30pm CDT. I will post it as soon as is out. The image in the OP should update on its own.

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He is saying there may be severe storms in the southeast Tonight?. I don’t understand

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It is possible in the early morning hours in those areas, yes. It is more him saying that the overnight threat is there for tonight, and if storms do develop they could go severe fairly easily and catch people off guard.