Why were there tornadoes today?

sfctmp_nWhen we ran our 13Severe Weather Index model yesterday, it showed us a bullseye around St. Louis for today. Indeed, they got it. There are numerous reports of injuries and fatalities today…perhaps because people don’t expect this level of activity at the end of December.

Today’s set-up included dewpoints in the middle 50s across much of the Mid-Mississippi River Valley. In addition, a high level of instability existed (with colder air aloft) which allowed thunderstorms to erupt, even before dawn across parts of Oklahoma and Arkansas. A strong cold front (with a thirty degree temperature spread across it). Check out the current temperature map which shows the incredible temperature difference!

bettycrockeringredientsStill, these factors aren’t enough to produce the wild weather day we observed. The frosting on the cake is the jetstream high above. An unusually strong speed max was located in Missouri today, the likes of which we usually only see in the spring months.

This set-up is very similar to the event in early January 2008 when tornadoes were spawned in Northern Illinois and Southern Wisconsin. The thing that saved us this go-around was the fact it took an extra day to melt the snow. Had we melted it all yesterday instead of today, we more than likely would’ve had tornadoes here.

While Tornado Watches remain in effect for parts of downstate Illinois and Indiana, the threat will wane significantly with the onset of night. Tornadoes will still remain possible well south into parts of Mississippi and Louisiana tonight and could affect revelers in New Orleans and Mobile. -ES

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Posted under tornado

This post was written by qni_it on December 31, 2010

1 Comment so far

  1. Tim [W Belvidere] December 31, 2010 5:05 PM

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