Diagnosing the likelihood of storm formation based upon a storm tower’s visual cues is not terribly difficult. There are a couple of cues that are quite meaningful in terms of whether a storm tower is going to become a storm or evaporate into thin air. Let’s break them down.
Cue 1: How crisp is the Storm’s Updraft Tower?
If a storm tower’s updraft is crisp or hard at the edge, that is a good sign the updraft is powerful. A wispy or mushy look to the updraft means it is struggling. The same is true if the updraft’s edge is ill defined. You want that hard, cauliflower look to the updraft tower to signify the upward push is strong.
Cue 2: How wide is the base? What is the trend?
A wide storm tower base that is getting wider is a sign of a strengthening storm. A narrow base or narrowing base is a sign of a weak updraft tower. You’ll generally want the base of the storm to be pretty wide to guarantee the updraft is powerful enough to best the cap, especially on dry line days.