We have a problem in meteorology. A big problem. We don’t have enough data from way up high in the atmosphere. Oh, we have more surface observations than we know what to do with, but it’s the higher levels of the atmosphere that really determine what happens down here.
The only upper-level data we have comes from weather balloon launches. These are released twice a day (morning and evening) from select NWS offices. The closest launch site to us is Nashville. We take these few data points and determine what the whole atmosphere is doing. And the atmosphere is constantly changing. Constantly….
The disturbances that develop in the atmosphere are hard to figure out, due mostly to the lack of upper-level data. Earlier today and, frankly, for the past several days it looked like a vigorous upper level disturbance would produced a derecho in Missouri that would scream through here tonight.
That never happened.
Why? I don’t know and neither does anyone else. The disturbance in Kentucky today may have robbed the Missouri disturbance off its energy? Lord knows they got slammed today. And just as that disturbance was passing to our north it was close to 6:00 p.m. That hour is notorious for being known as the hour the cap likes to break. The cap is a warm pocket of air at about 5,000 feet that can suppress storm development. But, when it breaks it can be a dramatic explosion of t-storms. That’s what happened this evening. This cap-breaking potential is why we warned all day of any storms that could fire off becoming very severe in the afternoon or evening.
The topography of the plateau probably helped break the cap too. Even now, we are the most active region in the state for storms. The derecho that we looked for all day still hasn’t developed and that is why everyone remains under a tornado watch.
Now, our cooler air (though not stable) is a boundary between the much, much warmer and more humid air to our west. This will likely cause us to have storms all night long, some of which could be severe.
Will we see tornadoes? Probably not. But, the amount of wind shear and instability is high enough to warrant a watch until at least 2:00 a.m. Plus, if any storm develops to our west, where the airmass is untainted, we could be looking at some potent activity.
If we get a long break and southwest surface winds bring that soupy air to our west back over us, we will increase our tornado potential. If storms stay continuous and keep the atmosphere mixed up, we’ll have less of a severe threat.
I know this is more than you wanted to know but now you know more than you did when you started reading this (ha).
This is an environment that favors lots of lightning and even hail, so be aware of that. Our lightning-terrified animals are in for a rough night. Take good care of ’em.
For now, the tornado watch continues. I’ll let you know if/when that is cancelled or extended.
Let’s hope for a cancellation.