1. Single Cell Thunderstorm:
   • Smallest and weakest thunderstorm
   • Characterized by a weak updraft.
   • Usually not severe.
   • Can contain small hail and brief, gusty winds.
   • Also known as "pulse storms."
2. Multicell Cluster:
   • The multicell thunderstorm complex is the most common thunderstorm type.
   • It is composed of multiple cells with updrafts and downdrafts at different stages in their life cycle.
   • Although each of these individual cells in the cluster may last for only 30 minutes, the entire multicell cluster may last for several hours, as old storms fade and new storm cells form.
   • Severe weather produced by the multicell thunderstorm is usually isolated and of short duration.
   • In the multicell storm illustration, cell 1 is the oldest ,while cell 4 is the newest.
   • Can be severe with large hail and damaging straight-line winds.
3. Multicell Line or "Squall line:"
   • Squall lines are simply a continuous or nearly continuous line of thunderstorms.
   • They are common along, or in advance, of cold fronts.
   • Strong to severe storms are possible. Large hail, damaging straight line winds and tornadoes are all associated with severe squall lines.
   • However, they are particularly known for producing strong straight-line winds.
In the muticell squall line illustration, storm motion is from left to right. Warm moist air flows up into the updraft (as represented by the red arrows) while rain-cooled air (blue arrows) descends through the downdraft. The leading edge of this rain cooled air is called the gust front and is often times accompanied by an abrupt wind change and sharp temperature drop. Along the gust front a distinct cloud formation often times occurs. This is called a shelf cloud. It marks the area where the warm, moist air meets and is lifted over the rain cooled gust front air. (Diagram adapted from C. A. Doswell III, 1985: The Operational Meteorology of Convective Weather. NOAA Tech Memo ERL ESG-15.)
4. Supercell Thunderstorm:
   • This is the rarest and most dangerous type of thunderstorm.
   • It is often seperate from other storms nearby.
   • A Supercells is characterized by a deep, rotating updraft called a "mesocyclone." Rotation is the precursor to tornadoes.
   • The supercell differs from other thunderstorms in that it has one primary updraft and one primary downdraft.
   • The updraft and downdraft are able to maintain a near steady-state coexistence.
   • The mesocyclone in a thunderstorm can extend several tens of thousands of feet up into the storm and averages two to six miles in diameter.
   • These storms are likely to be severe with large hail, damaging downbursts and long-lived strong tornadoes possible.
   • Tornadoes can form in this larger circulation (the mesocyclone).
   • The strongest and longest lived tornadoes come from supercell thunderstorms.

In the supercell storm example we are looking west or northwest. In Ohio, most thunderstorms move from either southwest to northeast or from west to east. We see one primary updraft (red arrows) which, in most cases, rotates counterclockwise. A mesocyclone-produced tornado would be located at the base of this updraft. A storm spotter should closely monitor the base of the updraft. Further toward the north, we would find the downdraft (blue arrows) which contains most of the rain and hail found in the storm. (Diagram adapted from C. A. Doswell III, 1985: The Operational Meteorology of Convective Weather. NOAA Tech Memo ERL ESG-15.)

Let's look at the supercell from a radar perspective. This a classic supercell that formed near the shores of Lake Erie on March 14, 2007. The center of the mesocyclone circulation is denoted by the red and yellow circles. Large hail is being produced in the purple areas. The hail and heavy rain also produced a microburst. That is: a small area of severe straight-line winds. The mesocyclone rotation produces the hook appearance as precipitation is wrapped around the southwest portion of the circulation. (March 14, 2007 sandusky hook echo)