List of SPC high-risk days

A high risk severe weather event is the greatest threat level issued by the Storm Prediction Center (SPC) for convective weather events in the United States. High risks are issued only a few times a year when forecasters at the SPC are confident that a major severe weather outbreak, namely tornadoes and occasionally derechoes, will occur on the given day. These are typically reserved for the most extreme events.

Limited details are available for days before the late 1990s, and it is probable that there were additional high risk days with no online documentation, especially in the 1980s.

Prior to 1997, data on high risk events is relatively scarce due to a lack of online documentation by the Storm Prediction Center. Most of the listed events from 1984 to 1997 are constructed from case studies on certain outbreak, namely for those in North Carolina, as well as storm chaser accounts. During this time period, at least 42 high risk outlooks were issued for the United States.

There were no high risk days in 2000.

There were no high risk days (for two consecutive years) in 2015 or 2016. The 31 months between high risk days in June 2014 and January 2017 is the longest since at least the 1980s.

...
Wikipedia