Preliminary investigation of the contribution of supercell thunderstorms to the climatology of heavy and extreme precipitation in the United States

The hazards attributed to supercell thunderstorms are primarily considered to be tornadoes, large hail, and damaging winds, but flooding from heavy and extreme rainfall is not as often considered with these storms. As a result there has been little research on the role that supercells play in the production of heavy and extreme rainfall events. In order to assess the contribution of supercells to the climatology of short-duration precipitation extremes the present study uses the Warning Decision Support System — Integrated Information to objectively identify supercell thunderstorms from mosaicked radar data during the year 2009 and associate them with high-resolution, accurate multisensor precipitation estimates at time scales of one hour. Supercells are found to be more likely than non-supercells to produce extreme and heavy precipitation, and comparisons are also made between storm types according to month.

► Storms are identified and classified as supercells or non-supercells using WDSS-II.
► Hourly rainfall is associated with each storm type using Q2 precipitation data.
► Supercells are more likely than non-supercells to produce heavy and extreme rain.
► A storm that produced hourly rainfall exceeding 30 mm is more likely a supercell.