Breakdown: Why fall brings a secondary severe weather season

Why fall brings a secondary severe weather season

MEMPHIS, Tenn. (WMC) - Most of us are familiar with severe weather in the spring and summer, but there is a secondary severe weather season in the fall mostly across the southeast.

The main threat is in the southeast which includes the Mid-South, but sometimes that threat can shift northward too. This spike in severe weather usually happens from mid October through November and on average can produce as many tornadoes as we see in March.

October Tornadoes
October Tornadoes (Source: October Tornadoes)
November Tornadoes
November Tornadoes (Source: November Tornadoes)

This secondary season is mainly caused by cold fronts and the jet stream sinking more southward. These cold fronts collide with warm, moisture laden air that is driven northward from the Gulf of Mexico.

Fall Severe Setup
Fall Severe Setup (Source: Fall Severe Setup)

Sometimes late season tropical systems can also be the culprit for this secondary season. In November there is an average of 2.8 twisters annually which is the same average for March.

The severe storm threats in the fall can mimic those that happen in spring bringing the threat of tornadoes, damaging wind, hail and torrential rain that could pose a threat of flooding.

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