What is the hardest thing about predicting where and when a tornado will show up?
On quite a few days not all the ingredients come together. So it may be unstable, but the winds aren’t ideal for tornadoes. Or the winds may be ideal, but it isn’t quite unstable enough for many strong thunderstorms that could spawn tornadoes. Those days are hard to judge the tradeoffs. On many days there is a warm layer aloft called a “cap” that may inhibit thunderstorms from forming. Other ingredients may be favorable on capped days, but thunderstorms may not form at all, or only in a part of the expected area. Most of the time we can tell that tornadoes will be possible in some portion of a state, but predicting which town will get hit is nearly impossible more than a half hour ahead of time.
