Radar is a little active on this Thursday morning with scattered showers and thunderstorms spinning around a weak upper-level disturbance crossing the area. These storms aren’t too much in the way of trouble, but there is a low-end Level 1 of 5 risk of severe storms for the late morning to early afternoon that clips some of our viewing area counties south of the Tennessee River. Overall, this is a very low impact ordeal, but there may be one or two storms with small hail or gusty winds. We don’t see any reason to believe there is a tornado threat with these, and it’s a lot more likely that we just don’t have any severe weather issues today.
The more attention-worthy storm threats begin Friday overnight into early Saturday morning. We still continue to have an Elevated Risk of severe storms across all of the area running from after 9-10pm Friday night into about daybreak on Saturday morning. This one is questionable, however, because of a capping inversion in the mid-levels and also the fact that the main upward forcing to trigger storms from the first wave will be pulling away to the north as we get deeper into the overnight. This is one of those low confidence but medium to high impact type threats if storms can get going in the area. We’re not sure of how many there will be, and there are increasing signs that the MS/AL portion of this threat area might possibly stay mostly quiet, and that may even be something that trends more toward being the case for even southern TN as well. However, if we do manage to trigger a few storms, the environment is set up in a way that it would be favorable for them to possibly be supercells, and there might be a strong tornado or two (EF2 or greater intensity). It’s one of those cases where if storms can form and sustain themselves, one or two of them might be bad news, but we’re not guaranteed they will be able to pull it off. You will need to have reliable ways of hearing warnings during the overnight in case something does happen.
The more substantial threat on the table comes Saturday into Saturday night. We will open up a long threat window from roughly around 10am all the way to 10pm, but there are increasing signals that the start of this may wait until after lunchtime. We just want to play it safe for planning purposes this far out and then will narrow a little as we get closer. It will remain a large window though because this is not a case of just one little quick line of storms that moves across the viewing area in 2 hours and then we’re done. There will be an open window where there may be multiple rounds of supercell type thunderstorms from the midday/afternoon into the early evening, before a final line along the cold front moves in by the mid/late evening.
***For clarification’s sake, the map above is not the NWS Storm Prediction Center map. There is no need to try to figure out if you’re in a Level 3 risk, a Level 4 risk, whatever. The map is simply showing you the areas where the risk is most significant compared to others (and their risk is still elevated), and that red Significant Risk is where WE feel the higher threat of strong tornadoes will be Saturday midday, afternoon, and evening. It’s NOT the SPC Level 4/5 risk, and it’s not trying to be (although we feel it should be farther north than it is and will likely get expanded or shifted north into our area). It is simply showing you where the higher strong tornado risk is located based on our forecast thoughts. You come to us for OUR forecast. This is it. We feel that if you wanted someone to just regurgitate the SPC outlook with no local experience, you could get that absolutely anywhere on the internet.***
What ultimately happens in the afternoon will be partially determined by how potential overnight/early morning storms behave. If, hypothetically, storms from overnight Friday night get in here and sit around Saturday morning and just rain and rain for hours and never move out, that would work over the instability in the atmosphere, shunt the warm front south of us and reinforce its placement there, and lower our severe storm risk for the afternoon and evening quite substantially. That is a scenario that I don’t 100% want to discount yet because we’re not fully into the high-resolution model range yet, although we are getting the Friday overnight portion into that range, and it’s trending less widespread if not staying quiet altogether. The one potential “out” we would have with this setup is for morning stuff to get in the way and work over the atmosphere. We never want to give you a bad forecast, but given what this setup is capable of, I would be thankful and willing to take the criticism of “blowing it” if that ends up happening and this all ends up just some heavy rain, lightning, and a little bit of gusty winds. However, the closer we get to this thing, the less and less it looks like that is likely to happen.
Assuming that the morning does stay mostly quiet or any morning storms fizzle or scoot on out of the way, we expect rapid moisture transport to continue across the area as a strong low-level jet pulls mid to upper 60 dewpoints into the area by late morning and early afternoon. The capping layer aloft that may hold back Friday overnight storms will also have dry air associated with it that may allow for some sun breaks during the morning to midday that allow our temperatures to climb into the 70s. As that happens underneath cold air in the upper-levels, significant instability sets up across Mississippi, Alabama, and into middle Tennessee. As that happens, the low-level jet over the area significantly ramps up in intensity by midday and the afternoon as the main storm system approaches from the west and southwest. That acts to significantly increase the wind shear and spin through the atmosphere. As the upper air system approaches, we expect the capping lid to break back over Mississippi and maybe up into southwest Tennessee and for supercell thunderstorms to form. As that happens, it is possible that the cap may also start to break closer to our area over northwest Alabama and southern middle Tennessee. There may be more than one focused area where supercell thunderstorms begin developing in the afternoon. These storms will be moving northeast quickly at speeds of 50+ mph. These storms will have the potential of damaging winds of 60-80 mph, hail possibly to golfball size, the potential of flooding, and a heightened risk of tornadoes. A few of these tornadoes may be long-tracked and intense. This is not the kind of situation like back on February 15th when Tuscumbia got hit where we have a few quick spin-up small tornadoes. Those are dangerous. But this is a setup that supports the potential for the large higher-end type tornadoes that get down and stay on the ground for 20+ miles in track length. These supercells would continue into the early evening as a more solid line would approach from the west ahead of the cold front that would move in during the mid/late evening. However, the atmosphere is setup that there may be supercellular structures embedded within the line, and those would have the potential for strong tornadoes too, in addition to any individual supercells still tracking out ahead of the line. Based on our current thoughts, that final line should be crossing the I-65 corridor and out of our viewing area by 9-11pm Saturday evening, bringing an end to the threat in our local viewing area. However, we will be monitoring to see if that needs to change as we get closer.
For those of you that suffer from storm anxiety, I know this is rough on you. I’m from central Alabama. I worked the April 27, 2011 tornado outbreak at WBRC FOX 6 in Birmingham. I know the fear that forecasts like this can trigger. We’ve been very cautious with our tone and our wording this week because we don’t ever want to scare or panic anyone. That is never our objective. However, we have to call it like we see it and give an honest and objective evaluation of the data we see based on the knowledge and experience we have with similar setups in the past. That is our job here at Tennessee Valley Weather, and sometimes, that unfortunately means telling you things that you don’t want to hear. Please remember that, even on a big tornado day which this may be, the statistical odds of it being YOUR specific house that’s hit by a tornado are really low. Back on April 27, 2011… which this will NOT be… there were 62 tornadoes in the state of Alabama that day, the largest outbreak in the state history, but only 1% of the land of Alabama was actually physically touched by a tornado itself. There were widespread storms, there were numerous tornadoes, but not every single everybody was directly hit by a tornado. Please take comfort in knowing that the chances of it specifically being YOUR home that is hit are low. However, the chances of it being SOMEONE’s hone in a higher threat area like this… are high. The chances of there being multiple tornadoes somewhere in the threat area is high. That’s why you HAVE TO be prepared… because although the chances of it being specifically YOU are low, the chances are HIGH that it will be somebody in or near the area, and that COULD be you.
One of the best things that can help with anxiety about this is preparing ahead of time. Not only are you getting yourself and your loved ones ready, but you are taking charge and giving yourself power in what feels like an uncontrollable and unknown situation. That helps us cope with stressful situations! Know where your shelter location is and have the plan in place for that now while the weather is still quiet. Use the basic tornado safety guidelines above to formulate your safety plan if you don’t already have one. Especially if you live in a mobile home, make plans now for where you will go to shelter. You cannot stay in a mobile home during these type of storms. You have all day today and all day tomorrow to finalize those plans. Helmets for everyone! Something as simple as a $5-10 bicycle helmet can save your life by protecting your head and neck from flying debris, but if your family has football helmets, motorcycle helmets, safety-rated construction hard hats, or even a metal cooking pot will do in a pinch… all of that can serve to protect your head from flying debris. We’ve learned over the years from treating ER doctors that the majority of people who are seriously injured or that die in big tornadoes are hurt by blunt force trauma to the head and neck region. You drastically increase your odds of survival if hit by a tornado if you’re protecting your head and neck from flying debris. Also, use the sofa turned upside down in the hallway, mattresses, pillows, and blankets to insulate your body from flying debris.
A critical component of being ready for a severe weather threat is having multiple reliable ways of getting the warning. Also, if you are reading this, you stay in touch with the weather… but not everyone does. You may have friends and family that are not even aware storms are possible Friday night and Saturday. Send them a message or give them a call or share our forecast info with them and make them aware. Give them a call or text if they come under a warning when the storms come through if you aren’t hunkering down yourself. You can save a life by being a part of the warning process by sharing this severe weather information with your friends and loved ones!
Take a big, deep, calming breath. Go through your safety plan today and the daytime of tomorrow while the weather is quiet, or formulate one if you still need to. Pay attention when the storms roll in and don’t hesitate to go to your safe place if a warning is issued, and we will get through this together. We will be right here to track the storms for you and give you the information you need to keep you and your loved ones protected!
