Climate-driven warmth aids two-day, early-spring severe weather threat

A large and intense weather system is poised to bring multiple rounds of severe weather across the Mid/Upper Mississippi Valley, Lower Ohio/Tennessee Valleys, and Deep South on March 14-15, 2025. NOAA’s Storm Prediction Center has issued a rare two-day “Moderate Risk” (level 4 out of 5) for parts of both the Midwest and Deep South.

While many factors contribute to a severe weather event, warmth is a primary driver. Temperatures across the region are forecast to be 15-25°F above mid-March averages. Human-caused climate change is making this kind of early-season warmth more likely, allowing temperatures to reach levels that support thunderstorm development..

Note: The forecast may evolve. Check the Storm Prediction Center for the latest severe weather outlook and use the Global Climate Shift Index map to stay updated on heat in your region.

How has climate change influenced temperatures during this severe weather risk period?

• Friday, March 14: A Moderate Risk of severe storms is forecast for portions of Missouri, Iowa, and Illinois by late afternoon, evolving into a nocturnal severe weather event. Strong tornadoes, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible.

  • According to the Climate Shift Index, temperatures in the region at risk will be 20-25°F above average and are at least twice as likely to occur due to climate change. 

• Saturday, March 15: Another Moderate Risk of severe storms is forecast across parts of Louisiana, Mississippi, and Alabama, with the potential for “significant tornadoes, damaging winds, and large hail” developing in the afternoon and continuing into the evening and nighttime hours. 

  • The Climate Shift Index indicates that in the region at risk, temperatures 5-15°F above average are currently 1.5 to 2 times more likely for mid-March due to climate change.

How does climate change influence severe weather trends? 

• One key indicator of thunderstorm severity — Convective Available Potential Energy (CAPE) — has increased with recent warming. Since 1979, springtime has seen an increase of 10 to 15 more days with CAPE values exceeding 1,000 J/kg, particularly in parts of the Central Ohio Valley, Kentucky, and Tennessee. This signals greater potential for severe weather.

• While the overall number of U.S. tornadoes each year hasn’t changed since 1970, tornado activity has become concentrated in more frequent outbreaks (days with multiple tornadoes). The frequency of U.S. tornado outbreaks is increasing faster for the most extreme outbreaks.

• The proportion of U.S. tornado fatalities occurring at night has increased by 20% since 1880, highlighting a growing risk associated with nocturnal severe weather events.

What do experts say?

Dr. Kristina Dahl, VP of Science at Climate Central, said: 
"This level of early-season warmth is striking — temperatures this far above average create an environment where severe storms can form more easily," said Dr. Kristina Dahl. "As climate change drives more frequent and intense heat, we’re seeing conditions conducive to the formation of  severe weather coming earlier in the year and across a broader swath of the country."

To request an interview with a Climate Central scientist, please contact Abbie Veitch at aveitch@climatecentral.org. 

How do we know climate change is influencing this heat?

The Climate Shift Index uses peer-reviewed methodology and real-time data to estimate how climate change has increased the likelihood of a particular daily temperature.

Reporting resources

• Climate Central’s Extreme Weather Toolkit: Severe Weather 

• Potential Energy’s Guide to Reporting on Unnatural Disasters