Weather Tidbits: Severe T-Storm Warning Categories

New severe thunderstorm warnings are explained in this Weather Tidbits. Starting on August 2nd, the National Weather Service will add a damage threat to severe thunderstorm warnings. The 3 categories from lowest to highest threat are Base, Considerable & Destructive. A Base or Baseline Damage Threat, will be the minimum criteria of a severe thunderstorm warning with a diameter of at least 1″ or quarter size and/or thunderstorm winds of 58 mph. Also when no damage threat tag is present, the damage is expected to be at base level.

A Considerable Damage Threat, has the criteria consists of hail of a diameter of at least 1.75″ or golf ball size and/or thunderstorm winds of 70 mph. A Destructive Damage Threat, has the criteria consists of hail of a diameter of at least 2.75″ or baseball size and/or thunderstorm winds of 80 mph. On average, 10% of severe storms reach this criteria each year across the nation. These storms will usually consist of events such as derechos involving straight line winds and supercell thunderstorms that can typically produce very large hail. Also, only storms of this criteria will trigger a Wireless Emergency Act (WEA) on your cell phone and storms of this criteria should be treated like a tornado warning.