Elevated & Surface-Based Storms: What Does it Mean?

You may have heard of the phrases ‘elevated storms’ and ‘surface-based storms’.  These are terms many in the weather world understand but are not often discussed in public.  Hopefully, this blog will help explain to you what it means and why it’s so important in forecasting severe weather.

It’s a commonly accepted theory that surface-based storms generally occur in warm sectors, the area of the warm atmosphere on the backside of the warm front.  Elevated storms tend to reside in the cold sector of a storm system.

Surface-based storms are usually the type of storms that can produce tornadoes.  Elevated storms are more associated with large hail and strong, damaging winds.  Of course, this doesn’t mean either type of thunderstorm has a corner on any mode of severe weather.

Example of elevated vs. surface based thunderstorms

A warm front draped from east to west across Iowa was the focal point for thunderstorm development.  To the north of the front, temperatures were in the 50’s.  Just south of the front, temperatures reached the 80-degree mark. That morning, the warm front pushed north out of Missouri and into Iowa.  But by the afternoon, the front reversed course and began slowly moving to the southeast.  As storms developed along the boundary, they moved to the northeast, in the opposite direction of the boundary.

This direction pushed the storms away from the front and into much colder air.  What did that lead to? Elevated-based storms.  These storms lacked the surface heating to generate super cellular signatures that would lead to organized rotation and possibly tornadoes. What the cold air instead did was greatly enhance the threat of large hail inside those storms. 

Had those same storms taken shape south of the warm front, or lingered along the boundary, they could have taken root in the heating at the surface.  That difference could easily have produced the conditions favorable for tornadic development.

I hope this better explains the difference between surface and elevated-based storms and what they mean during a severe weather event.  They are keywords when it comes to thunderstorm development and better help us understand why certain storms behave the way they do base on where and when they develop during a stormy day or night.