The peak of severe weather season here in the Tennessee Valley is early May, but in other parts of the country the peak has yet to come. This is the case for what is commonly referred to as Tornado Alley (stretching from Texas to Nebraska), where severe weather season peaks closer to June.
This week’s forecast for Tornado Alley is lining up closely with the climatology.
The Storm Prediction Center has highlighted a slight risk of severe weather from Texas to Nebraska on Tuesday, with an enhanced risk over Oklahoma and Kansas.
Not only does this risk area outline much of Tornado Alley, but it’s also very close to May 16th severe weather climatology data.
A storm system will be slowly moving eastward over the high plains with a cold front extending south into Texas, providing forcing for storms. Ahead of this system will be a strong southwesterly flow, which will bring in warmth and moisture to provide instability. By the time the cold front makes it to Northern Alabama it will likely have weakened, while the best forcing will be located to the north.
Why is our severe weather season usually earlier in the year? To put it simply: seasonal changes help drive severe weather seasons. So, just like summer heat hits us first, so usually does severe weather. During winter the jet stream tends to dive further south. When spring rolls around it starts to make it’s move back to the north. That means the storm track is closer to Southern regions, like the Gulf states, earlier in Spring. By late Spring it has moved to our north, closer to regions like the plains states.
Keep in mind tornadoes are possible year round. In fact, you’ll notice a small area in the climatology map above near the Appalachians that is also highlighted. This is where cool, dry air can slip down and collide with warm, moist from the gulf to spark off storms.