Let’s start with this: more deadly tornadoes in unusual places, like Kentucky, are not necessarily all about climate change. That assumption would be a stretch. Saying that, we are seeing more tornadoes east of the Mississippi. Climate Central sent out a full report on this and I want to break down the more salient points.
First, you and I both know it is a LOT warmer these days across the whole country. In fact, this year alone we have had almost three times more record highs than we have had record lows. Here’s a snippet from National Oceanic and Atmospheric Administration’s National Climatic Data Center:
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You can find the full tables of record highs, lows and precipitation by day, month and year right here. For monthly and all-time records, the relationship of record lows to record highs is 1:4. That’s right, FOUR TIMES more record highs than lows!
And the month of December has been crazy hot all across the entire United States. Look at the “above normal” graphic for the first two weeks:
That’s a lot of yellow, orange and red!
Heat and moisture supply the energy in the atmosphere and it’s pretty obvious the heat is there, even in “winter” months. So where is the moisture? In the eastern U.S.! You can see that from this past week’s Drought Monitor.
It’s easy to compare the two: the area of most above normal temperatures is also where there is no drought, so there is plenty of moisture to lift into the atmosphere for severe weather.
Thus the shift EAST
Looking at that basic trend, you’d expect the tornado season to expand eastward (not shift -- there are still plenty of tornadoes in Tornado Alley from North Texas to North Dakota and those aren’t going away). That expansion is clear over the past four decades:
And not only are the outbreaks expanding eastward, there are more tornadoes in those outbreaks. Why? That takes us back to the warmer climate.
Make of this trend what you will, more frequent tornado outbreaks are occurring across the country and more of them are happening to the east. More reasons to stay “weather aware!”
Frank