The overnight update from the NWS Storm Prediction Center raised a large part of our viewing area to a Level 2 of 5 risk of severe storms for Saturday afternoon and Saturday night. The overall forecast thinking hasn’t changed. This is an eastward shift in their risk areas that we had been expected, and that we are in agreement with based on data we have seen over the last 12-24 hours. This is still a lower-end threat, and it’s also still an uncertain threat where if one or two of the severe weather ingredients underperform just little bit compared to what the data shows, the severe weather threat may fail to perform altogether. That’s often how these severe weather threats behave during the late fall and winter months. Having said that, we see enough cause for concern to mention the potential for a few strong to severe storms being possible. Worst-case scenario is that would include the potential for a few tornadoes. However, that would require those severe weather ingredients to perform to their full potential that’s seen in the computer model data, and we can’t guarantee that’s going to happen. But it’s enough of a risk that you need to pay attention to weather information as we head into Saturday and be ready to act if warnings are issued. There is also the potential for a few storms to produce damaging wind gusts of 50-60 mph, and even away from any thunderstorms, pressure gradient winds may gust as high as 30-40 mph at times Saturday into Saturday night. There is also a low potential for a couple of storms to have the potential for pea to dime size hail, but the hail threat isn’t a big concern. What may be the threat type that has the highest chance of verifying is the expected heavy rainfall and the potential for some localized flash flooding (the street variety kind especially).
Our in-house Baron Futurecast model above gives an overall rough idea of the timing of the storms. You can click (or tap for mobile devices) each image to bring it up to full size. We expect a few spotty showers to be possible later tonight and into Saturday morning. Temperatures on Saturday morning start in the mid 50s to as mild as near 60 by daybreak, and then we warm into the mid to upper 60s by afternoon as we see a few breaks of sunshine in the cloud cover. I can’t even rule out some isolated areas hitting the lower 70s with a little bit of sun. By mid afternoon, some of the high-resolution model data is showing the potential for a few cellular stronger storms to develop in north Mississippi and northwest Alabama well out ahead of the main band of storms that move through during the evening. The Baron model here isn’t as aggressive with them, but as we’ll show in a moment, the HRRR model is, as are other reliable high-resolution models. We would have to watch these closely for the potential to become severe and possibly rotate. This would probably be our best chance to have the threat of a few tornadoes verify. That type of risk may start as early as 3pm or so in the mid afternoon. By 7-8pm, the main band of storms looks to approach from the west, and it will slowly work across our area from west to east through the late evening and overnight, before the cold front clears our area by 2-3am. That band of storms may have the potential for some isolated pockets of damaging winds gusts as high as 50-60 mph, and even it may have the potential for a tornado. However, as we get later into the evening, the slow-moving nature of the line will allow it to work over the atmosphere, and the severe storm threat will gradually weaken even before the line fully moves through. That weakening of the threat may happen as early as 10pm to Midnight, but we’re going to hold in place a non-zero severe risk until the cold front clears the area in the 2-3am timeframe just to be on the safe side.
As mentioned above, the HRRR model (along with others) is more robust and aggressive with the potential for individual cellular storms becoming potentially strong to severe over the area during the mid afternoon to early evening (roughly the 3p-8p timeframe). While it’s not a guarantee that will be the case, it definitely is a possibility. Should these individual storms be able to organize and grow stronger as seen here, they may be able to function as supercells with the potential for a few tornadoes. The word “supercell” usually causes extra concern when people hear it because we know those are the type of storms that are most likely to produce the larger long-track type of tornado. HOWEVER, the atmosphere does not appear to be set up for that magnitude or caliber of tornado threat, even if we are able to see cellular storms like this. It’s just that a cellular storm, as opposed to a solid line, would have a slightly better chance of producing a tornado because it’s not competing with or being interrupted by surrounding storms. The tornado risk would still be of the lower-end variety. It would just be a bit more likely to verify if we do indeed see these individual cellar storms evolve as shown here. After that, the HRRR and other models agree with the Baron model concerning the main band of slow-moving storms moving in after 8pm and shifting slowly across the area into the late overnight, carrying with it a low-end severe threat but gradually weakening as it moves across.
While this is a lower-end threat, it is still something you need to take seriously and make sure you are prepared for. You need to make sure you have a safety plan outlined ahead of time (today, before storms threaten on Saturday, is best so you aren’t rushing and panicking at the last minute while a storm is racing toward you), and you need to make sure you have multiple reliable ways of hearing warnings… including something that can wake you up out of your sleep since this threat will carry into the overnight hours. Above is some information you can use to help you formulate a safety plan if you don’t already have one, as well as ways you can stay updated with weather information from us. We will have the weather center staffed Saturday and Saturday night, and we will be ready to provide LIVE coverage on all our broadcast platforms should warnings be issued in our viewing area across southern middle Tennessee, northwest Alabama, and northeast Mississippi. Our viewing area counties are as follows: Tennessee: Hardin, Wayne, Lawrence, Giles, Lewis, Maury, and Marshall. Alabama: Lauderdale, Colbert, Franklin, Lawrence, Limestone, and Morgan. Mississippi: Tishomingo. Should a Tornado Warning be issued for any of those 14 counties, we will have LIVE NON-STOP coverage on all of our broadcast platforms until the warning has expired, has been cancelled, or the danger has otherwise ended. That is a commitment and a promise that we make for each of those 14 counties, 24/7/365… regardless of the time of day or the day of the week it is. We give all 14 of those counties equally dedicated coverage, and we do not pick favorite counties or discriminate any one county against any of the others. We’ll be here to keep you advised should severe storms threaten on Saturday!
