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Severe storms a very real threat later this evening through Saturday morning. Tornadoes possible.


The overnight update from the Storm Prediction Center maintains the location of the Level 3 of 5 and Level 2 of risk severe weather risks across our viewing area for this Friday evening through early Saturday morning. There is an elevated threat of tornadoes (a few strong, long-track tornadoes possible) and damaging wind gusts of 50-70 mph in the Level 3 area; however, tornadoes and damaging winds are very possible in the Level 2 of 5 risk area, and even possible in the Level 1 of 5 risk area that runs from Huntsville AL to Double Springs AL and eastward.


(Scroll through the images to see the full timeline of the Baron Futurecast Model)


Our high-resolution Baron Futurecast model starts the day off with a few spotty showers by daybreak and temperatures already warming into the low to middle 60s areawide as a strong south wind brings warm, humid, unstable air northward from the Gulf of Mexico. By afternoon, with the continued strong south winds and a few sun breaks at times, we look to warm into the low if not mid 70s areawide. Much, if not all, of the day looks to remain quiet, with just a few showers or maybe an occasional rumble of thunder at times. Even through the evening hours, the Baron model holds off any storm development across our area. Other models do develop cellular strong storms during the mid to late evening, casting some uncertainty on the evolution of what happens in the evening hours. We will talk about that in a moment. After midnight, the Baron model has rapid supercell development back in west Tennessee and north Mississippi that moves toward middle Tennessee and northwest Alabama in the 3-5 AM timeframe. However, by the time the storms reach the U.S. 43 corridor, this run of the Baron model starts to congeal the storms into more of a solid line. Other models (and previous runs of this model) do not do that and bring the "line" across as a band of supercells instead. IF the band of storms does start to transform into more of a solid line like this, that would transition the greater risk from tornadoes over to damaging straight-line winds. HOWEVER, even in this case, tornadoes would still be very possible, and we wouldn't be able to completely rule out a strong tornado. This would be a similar situation to what happened in northwest Alabama back on December 16, 2019. As the line moves across the I-65 corridor in the 8-9 AM timeframe, the Baron model weakens it with time as the main dynamics move off to the north, but there may still be severe thunderstorm warnings or even a few tornado warnings with the line by then. However, the line will be moving out of our area by that time, and the threat in our local viewing area will be winding down.


Other high-resolution models, like the HRRR model shown here, have a somewhat different evolution that has to be considered. The HRRR has a few scattered showers or maybe a rumble of thunder into the morning and midday also, with temperatures climbing into the low to mid 60s by daybreak. By afternoon, the HRRR also agrees that there will be occasional cloud breaks that, in conjunction with the strong southerly winds, will allow temperatures to warm into the low to mid 70s areawide. However, this is where things start to differ. By the early to mid evening hours, the cap is weaker with the HRRR, and it has individual cellular storms attempting to develop over north Alabama in the open warm sector. IF storms like this are able to form, they would be in an environment favorable for rapid strengthening into supercells, with an enhanced potential for tornadoes. It's very uncertain if these are able to form, however. By late evening and toward midnight, the HRRR starts developing the main round, but instead of developing it on the front to the west, it develops it along the low-level jet axis farther east over north Mississippi and southwest Tennessee. This is important because it not only speeds up the timeline a little, but it develops the storms farther away from the linear forcing on the front and in an environment where the vertical wind fields are more supportive of them becoming and then staying supercells instead of rapidly forming into a solid line. IF this is the evolution that happens, this would increase the potential for tornadoes, including the potential for a few long-tracked strong tornadoes. An initial wave of these supercells move into portions of middle Tennessee in the 1-3 AM timeframe on this model, while another wave of cellular storms develops over northeast Mississippi and pushes into our more immediate viewing area in the 3-4 AM timeframe. These are more supercellular in nature until crossing east of U.S. Highway 43, and then they start congealing into a line of storms with embedded supercells. This continues across southern middle Tennessee and northwest Alabama before moving out of our area by 8-9 AM. IF this evolution happens (and this is similar to the NAM model, the various WRF models, and the previous runs of our Baron model), this would increase the tornado risk deeper into southern middle Tennessee and northwest Alabama, including the potential for a few long-track strong tornadoes.


Regardless of the eventual evolution of everything, it looks like the threat ends for our viewing area counties by 8-9 AM with cooler and drier air moving in through the rest of the day behind the cold front.


While the weather is still quiet in the daylight hours, take the time to review and finalize your safety plans. Make sure you have identified your shelter location if a warning is issued, and if you are in a mobile home and have to leave, make sure you identify ahead of time today that that location will be open during the overnight hours. Make sure you have multiple reliable ways of hearing warnings, including methods that will wake you from your sleep since this is an overnight threat. We will be fully staffed in the Tennessee Valley Weather Center to provide live coverage as conditions warrant, and if any of our viewing area counties are issued a Tornado Warning, we will have LIVE NON-STOP coverage on all of our platforms until the danger is over.

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