How do supercells form from a thunderstorm

In addition to the standard necessary ingredients for a thunderstorm instability , moisture, source of lift , supercells require strong " veering " of the winds, which means the winds are turning clockwise with height. So, for example, the surface wind could be out of the southeast, wind at the mid-levels will be out of the southwest, and winds at the upper levels will be out of the northwest.

The turning of the winds with height helps the thunderstorm develop its most essential component: the mesocyclone. A mesocyclone or "meso" for short is formed when a thunderstorm updraft meets veering winds. As the air rises in the thunderstorm, the winds will begin to twist the updraft until the whole column of air is rotating.

Although each storm is different, the meso is usually found in the right rear flank of the supercell and is typically miles wide. Technically, the mesocyclone is defined as the radar signature that appears if one is present a yellow circle on Doppler velocity products , but you can often see the rotation with your bare eyes. While each storm is different, most supercells usually have the following parts:.

There are three types of supercells: low precipitation, classic and high precipitation. The definitions of these types are exactly what you would expect, but they have some different consequences. LP supercells usually form in dry regions, where there might be just enough moisture to form the storm, but not enough moisture to rain very hard. You can usually find the updraft on the rear flank back of the storm, and the meso will be more defined and obvious. On radar, an LP will not show up as a hook echo because there's not enough precipitation within the storm to provide the reflectivity.

These storms might not look that strong, but they can pack a punch. LP supercells often produce tornadoes and large hail. As we shall see, circumstances keep some supercells from producing tornadoes, even with the presence of a mesocyclone.

Photograph by: Moller Even though it is the rarest of storm types, the supercell is the most dangerous because of the extreme weather generated. This storm was producing baseball hail east of Carnegie, Oklahoma, as it was photographed looking east from 30 miles. From right to left south to north , we note the flanking line, main Cb , and downwind anvil above the precipitation area. This circuit of rising and falling air is called a convection cell.

If this happens a small amount, a cloud will form. If this happens with large amounts of air and moisture, a thunderstorm can form. Thunderstorms can consist of just one convection cell, multiple convection cells, or even one extremely large and powerful convection cell.

Below is a description of three types of thunderstorms, classified by their structure: single-cell, mulit-cell and supercell. All thunderstorms begin with air rising into the atmosphere to form a convection cell, but the air can be lifted in different ways.

Another way to classify thunderstorms is by the location where they form and the reason that air rises.