Since the late weekend and the start of the work week, we have been starting to outline the potential for heavy rain and stronger thunderstorms being possible in our area Friday and Friday night. While exact specific details on the evolution of the threat, the specific timing, etc., are still murky because of how small scale details while play out and affect the final outcome, the overall big picture of the threat is starting to come more into focus. The NWS Storm Prediction Center has done what we expected and now expanded their Level 2 of 5 risk of severe storms to include all of our viewing area across southern middle Tennessee, north Alabama, and northeast Mississippi. While off and on rounds of heavy rain and thunderstorms will be possible as early as before sunrise early Friday morning and carry all the way through the predawn hours of Saturday morning ahead of the final cold front, we think the main focus timeframe for the potential for stronger to severe storms will likely run from the mid/late evening of Friday, through the overnight into the predawn hours of early Saturday morning. However, because we aren’t yet sure of the exact specific details of the smaller-scale evolution of these clusters of storms and how that affects the environment just yet, we are accounting for the potential that strong/severe threat could start as early as Friday afternoon. While those question marks won’t allow us to be able to nail down the specific magnitude of threat types just yet, we can see that the overall big picture of multiple rounds of strong storms and heavy rain may temper the environment some and is very likely to keep this from being a higher-end type severe storm threat. That’s not the type of day we look to be facing. That doesn’t mean it’s any less important to take seriously, pay attention, and prepare though. The threat does still include the potential for storms to produce damaging straight-line winds of 50-65+ mph that strong enough to knock down trees, knock down power lines and cause outages, and cause damage. The threat is also there for a few isolated tornadoes as well, and while it’s not a higher-end tornado situation, it’s not a bottom-of-the-barrel type of threat either. It is a legitimate threat that will probably make a tornado watch necessary (unless the overall threat weakens as a whole), with a decent chance of a few tornado warnings, and there could certainly be a few instances of tornado damage. We have no reason to think we’re talking about the bigger long-trackers or anything like that, but an EF0-EF1 tornado can take a life too, and it’s just as important to take those seriously as well.
What is probably the most likely hazard type, regardless of the severe storm risk, is the rounds of heavy rain and thunderstorms leading to the potential for flash flooding…. not really the wash-your-home-away type flash flooding… but the street flooding variety and low-lying areas being a problem. Yes, we have been dry for a while, but several inches of rain in such a short amount of time (and the ground being a little harder because of drought) would mean it can’t absorb as quickly and there would be runoff that would likely lead to some flooding and flash flooding. The general rainfall total forecast from the NWS is for an areawide 2 to 4 inches of rain as of their latest update. That gives pretty well with what we see in the modeling. There is the potential for rain totals to be close but slightly less than that to the immediate north of where the heaviest corridor of rain sets up, but even those rain totals would likely be reasonably close to 2 inches. Within the corridor of heaviest rain, the Baron 3k Futurecast model and Euro agree in the 2-4″ range with isolated heavier totals being possible. The GFS model shows a swath of heavier rain, in the range of 4-6″ or so. This is not unbelievable, but until the other models start leaning in this direction, we can likely frame it as the fully believable worst case scenario for the event.
So, what do you do with this knowledge? You take it and you plan ahead. You don’t panic. Remember that knowledge is power, and now that you know there is something to pay attention to, that knowledge equips you to plan for it and be ready for it. That helps fight storm anxiety that you may have. Make sure you have reliable ways of hearing warnings, including something that can wake you out of your sleep at night (weather radios and the WeatherCall service we outline above are GREAT for this). Make sure you have a safety plan outlined and that you and your family are aware of it and it’s easy to put into place. Make sure you stay weather aware. We will be here to track the storms, keep you informed, and get you through it… as we always are!
