How fall can bring a secondary peak in severe weather

November started off on a stormy note across the Mid-Missouri River Valley, as a strong low pressure system brought gusty thunderstorms, several inches of rainfall, and a risk for severe weather that luckily never materialized. While severe weather is most common in spring and early summer, fall can also bring an uptick in damaging thunderstorms. This is true for much of the continental United States, including Northwest Missouri and Northeast Kansas.

Tornadoes, damaging winds, and hail tend to occur with highest frequency from late March through early June in this part of the country. During this time, the atmosphere is often primed for severe weather with a good supply of moisture, wind shear, and unstable air as the warm season settles in. Similarly, the fall transition from warmer months to colder ones can also create opportunities for strong to severe storms. Fall fronts and low pressure systems generally provide plenty of wind shear to support severe thunderstorms. However, deep moisture and heat related instability are often more limited compared to spring and early summer. 

What some call the secondary severe weather season runs from October through December in the Central Plains and most of the Midwest. As history reminds us, some falls are quieter than others. About two years ago a significant straight-line wind event damaged trees and structures in parts of Holt, Nodaway, and Atchison counties Oct. 30, 2024. The fierce line of storms produced winds clocked at 90 mph in Falls City, NE before crossing into Northwest Missouri where three semi-trucks were turned over on I-29 near Craig, MO.

Roughly three years earlier, a full fledged tornado outbreak occurred in eastern Nebraska and parts of Iowa in mid December of 2021. Over 63 tornadoes struck Iowa alone, along with a derecho that also produced 70+ mph wind gusts in Northwest Missouri and Northeast Kansas. 

Tranquil autumn days will almost always out-number turbulent ones in the bigger picture. The same will be true for local skies over at least the next week. Even so, mother nature could still throw a few fall curve balls before the year ends. A reminder to stay weather aware no matter the calendar date.