A “high risk” severe weather forecast is the most urgent message that NOAA’s Storm Prediction Center (SPC) can issue prior to a severe weather event. When a “high risk” is declared, it signifies a high level of confidence in the potential for severe weather on a particular day in any part of the country. This highest level of severity, ranked from 1 to 5 in the SPC’s daily severe weather outlooks, demands the attention of meteorologists each time it is announced.
So, what exactly does a “high risk” mean? It indicates that the nation’s top severe weather forecasters are particularly concerned about the likelihood of one of the following scenarios occurring in the specified area:
– A tornado outbreak featuring numerous intense and long-track tornadoes.
– A long-lasting derecho-producing thunderstorm system that brings hurricane-force wind gusts and widespread damage.
While the most detailed documentation on high-risk outlooks is available for those issued in this century, there have also been documented cases in the 1980s and 1990s. On average, the SPC has issued a level 5 high-risk forecast two to three times per year from 2000 to 2024.
The last high-risk forecast prior to March 2025 was on May 6, 2024. Notably, 2003 and 2010 had the highest number of high-risk forecasts in a single year, with six each. Conversely, some recent years like 2020 and 2022 did not see any high-risk forecasts at all. The period between June 2014 and late January 2017 stood out as the longest stretch without any high risks being issued during this century.
From 2000 to 2023, the months of April and May accounted for nearly two-thirds of all high-risk days, emphasizing the volatile mix of warm, humid air and an active spring jet stream typically present during these months. While high-risk outlooks are more common in spring and early summer, there have been instances of such forecasts in fall and winter, including the first-ever January high risk in 2017.
Throughout the years, high-risk forecasts have predominantly covered regions in the Midwest, Plains, and South of the United States, with each region experiencing its share of severe weather events. Despite variations in the frequency and location of high-risk forecasts, the SPC’s track record in issuing these alerts has been solid, with many forecasts aligning with the severity of the anticipated weather events.
When evaluating the accuracy of these forecasts, it can be likened to reviewing the performance of professional sports teams’ draft picks years later. Nearly three-quarters (48) of the high-risk forecasts proved to be reliable. One notable instance was the outbreak on March 31-April 1, 2023, where the Storm Prediction Center (SPC) recorded 138 tornadoes across the Midwest and South in just 24 hours, one of the highest numbers in a single day on record. Other high-risk forecasts that led to significant outbreaks included the Super Outbreak in late April 2011, as well as more challenging and out-of-season predictions like the Midwest outbreak in November 2013 and the Super Tuesday outbreak in February 2008.
On the flip side, only seven of these high-risk forecasts were considered “busts,” indicating that the forecast did not result in the severe weather anticipated – often due to a lack of tornado activity in the designated high-risk area. Factors such as competing severe thunderstorms can contribute to a forecast not meeting expectations, as seen in the case of the high risk issued on May 18, 2017.
One recent example occurred on April 27, 2014, when a small section of Arkansas was highlighted, but only a few tornadoes occurred in that region. The remaining 10 cases did not clearly fall into the “hit” or “bust” categories. For instance, the high-risk forecast issued on April 5, 2017, in the Southeast appeared to accurately predict tornado activity in Georgia, yet the surrounding areas reported more severe weather incidents.
These instances highlight the importance of taking all severe thunderstorm risks seriously, not just those designated as high risk. It’s crucial to be prepared rather than panicked. In situations of high risk, where severe thunderstorms are likely, staying informed through various channels such as local media, NOAA weather radio, or social media is essential. Ensuring your smartphone is charged and set up to receive alerts can be a lifesaver in emergencies.
Knowing where to seek shelter and having a plan in place ahead of time is critical, especially if you live in a mobile home. Being proactive and prepared for severe weather events can make a significant difference in safeguarding yourself and your loved ones.
He earned his Master’s degree from Colorado State University, focusing on dual-polarization radar and lightning data. His passion lies in extreme and unusual weather phenomena. Connect with him on X (formerly Twitter), Threads, Facebook, and Bluesky.
