Sunday, May 26, 2024

Afternoon Update


So this has been a rapidly evolving weather situation setting up today, one of the more unusual ones I've ever seen. Areas around St. Louis into Northwest Tennessee have been upgraded to the Moderate Level 4/5 Risk for severe weather. 

And roughly the Northern half of the TN Valley is now under the Enhanced Level 3/5 Risk. The rest of us remain under that standard Slight Level 2/5 Risk that we were in last night. 

It looks like the hot zone for supercell thunderstorms to fire up this evening and tonight is going to be near St. Louis Missouri, and then they will track mostly into Kentucky and Tennessee. Far North Alabama is included in the hatched area for a 10% tornado probability though. And that hatching does mean we're probably dealing with some supercell thunderstorms, where the damage, including if it's tornado damage, could be fairly substantial. 

All of our Tennessee counties are now outlooked for a 10% chance of a tornado, including possibility of one that does fairly significant damage. And that risk also includes cities like Huntsville, Scottsboro, Athens, Decatur, back to Russellville and the Shoals, Florence. 

Places like Cullman, Hamilton, Jasper, Guntersville, up to Rainsville and Fort Payne are still under the basic 5% isolated tornado risk as of right now. 

The damaging thunderstorm wind threat has also been enhanced to 30% for about the Northern half of North Alabama there. And the hatching you see further into Tennessee means winds of hurricane force (like a minimal hurricane, probably 75-80 mph winds) are possible in some storms. So up there I've take a severe thunderstorm warning seriously as well even if it does not show tornadic rotation. 

The hail threat remains basic 15% for all of our area, except that 30% hatched area does clip Waynesboro. That's where golfball-sized hail or larger is a good possibility. The severe hail for most of us is expected to be coin-sized, not ball-sized. 

But basically all of us need to remain weather alert the rest of today and tonight and have a safe place to go to if you go under a warning polygon. At least get out of a mobile home and stay with somebody in a sturdier house before severe weather gets to you. Or use a public shelter if you have to. 

Remember the basic ideas for sheltering in a site-built home:

* Away from windows.

* Lowest floor, whether that means a basement or just the ground floor.

* Small room like a bathroom, closet, or hallway.

* That room puts some walls between you and the outside, so probably near the center of the building is best.

* Cover your body in case of debris that could fall or go flying around, especially protect your head the best you can. Get up under something sturdy, use pillows/blankets, and/or wear a safety helmet. 

Get alerts from your phone or from a weather radio, don't rely on outdoor sirens as first source. 

We'll have to watch any supercells which will mostly form in Missouri in that 15% hatched area this afternoon and evening. And it is not out of the question for them to form even in North Alabama. But overall I think our main threat will come later tonight close to Midnight, between then and about Daybreak, when the storms have formed into an MCS cluster and then that'll probably morph into a squall line (QLCS). Our main threat is damaging winds, a little bit of a large hail threat, but we could see a few tornadoes in the region too, especially in that 10% hatched area. And all of us need to be prepared just in case. As simple as these precautions may sound, sometimes they actually save people's lives. And even if it's not that dramatic, they can keep someone from being seriously injured if they take a direct hit from a severe thunderstorm or a tornado. Even if it only means the difference between having your nerves shaken up and having to get stitches because you got cut by a window blowing out . . . it's worth the precautions. Even if a tornado looks weak on radar, or it looks more like damaging straight-line winds, I'd go ahead and play it safe with this event. After this one, we're done with our severe weather season. And the start to summer is looking really mild. Won't be that way all season, of course, probably the opposite if I had to guess, but at least we get one week of nice, mild weather behind this storm system. So everybody stay safe while things may get stormy tonight. 

4:27 PM - This is the area of greatest concern for now, supercells forming in Missouri that may end up producing tornadoes that can do a lot of damage. It actually is similar to their threat in the Plains last night. It really ramped up. 

Most likely, our threat around here will come close to Midnight or even after Midnight in the form of a squall line. I think these supercells will form a cluster and then a squall line as they push East and then the whole thing slowly drifts South too. And late tonight/into wee hours tomorrow morning, we will deal with that squall line. 

We could see supercells down this way between now and then, but the atmosphere appears to be capped for now, and the risk of that is low. 

4:53 - The Winfield weather radio transmitter is out of commission. People can still tune to the Florence, Tuscaloosa, or Aberdeen (MS) transmitters instead. 

8:31 PM - Kentucky is the current hot spot for severe thunderstorms and tornadoes. Several of these tornadoes this evening in Missouri and Kentucky have been confirmed with damage and a lot of good video footage. Remember that much of Tennessee is outlooked for a significant threat of damaging thunderstorm winds too. So take any Tornado or Severe Thunderstorm Warnings seriously tonight. 

Our window opens up around Midnight or so in North Alabama and bordering counties of Southern Middle Tennessee. These storms will likely be approaching in the form of a squall line, which while weaker, should still carry a threat for damaging thunderstorm winds, large hail, and isolated tornadoes. And storms in a squall line can still do some damage sometimes. So no need to get overly alarmed by any scary videos or pictures you've seen from other states so far today (or from yesterday in the Plains). But we do need to respect whatever leftover severe weather threat we get from this system anyway. 

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