The Storm Prediction Center puts out a "High Risk" of severe weather for the worst of severe weather outbreaks. Such outbreaks are relatively rare & confined to a set of conditions that produce the most intense, concentrated severe weather over a large area.
So what is the frequency of "High Risk" days in our viewing area?
Such solid, reliable archives for SPC Convective Outlook only go back to about 1990.
Convective SigMets (early daily convective outlook text) was established in 1978 with first PDS watch issued in 1982. The first Day 2 Convective Outlook occurred in 1986, along with the introduction of the Mesoscale Discussion, which precedes watch issuance.
The first second Day 1 outlook did not occur until 1995 with an evening outlook at 02z.
HIGH RISK DAYS PER DECADE IN OUR VIEWING AREA:
1990-1999: 3 (Despite the tornadoes in the area & the big tornado outbreak in the Southeast U.S. November 22, 1992, it was actually a forecasted MODERATE RISK, not HIGH. Also, there was a big outbreak with tornadoes on May 13, 1995, but the HIGH RISK was just west of the state line into Illinois & we were in the MODERATE RISK area).
2000-2009: 2
2010-19: 3
2020-25: 0 (So Far)
So, we have had 8 "High Risk" days in 32 years in the viewing area. This translates to SPC High Risk severe weather situation every 4 years in our area. However, we have not had a High Risk outbreak since November 17, 2013.
We tend to average around 2 per decade.
HIGH RISK DAYS & WHAT TRANSPIRED IN THE VIEWING AREA 1990-2022 are below.
In each of the High Risk days, significant severe weather outbreak occurred in the viewing area.
March 28, 1991
June 17, 1992
April 19, 1996
October 24, 2001
May 30, 2004
October 26, 2010
June 12, 2013
November 17, 2013
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