How does the November 17th tornado outbreak compare to what typically happens in November?
The Storm Prediction Center's preliminary reports range from 70 (filtered) to 83 (unfiltered). Even though the numbers will likely change after the National Weather Service crews have a chance to survey the reported touch downs, this is likely to go down in history as one of the most active tornado days in the month of November.
Here are some facts about November outbreaks.
Excluding this event the worst November tornado day: November 10, 2002 when 51 tornadoes rated EF-1 or higher hit
Worst November multi-day outbreak: November 21-22, 1992 when 83 tornadoes rated EF-1 or higher struck from Texas to the Carolinas; 20 of those were EF-3 or higher. That outbreak was responsible for 26 deaths
Total EF-3 or higher November tornadoes from 1950-2012: 166
Total EF-4 or higher November tornadoes from 1950-2012: 22
Last November day with multiple EF-4 or higher tornadoes: November 24, 2001 with 3
This is also going to rank as one of the most active tornado days for all of 2013 to date. That’s not saying much, though, as 2013 has been an incredibly quiet year for tornadoes.
Here's a rundown of this year compared to the average:
Number of tornadoes this year through November 17: 886 (753 when adjusted for overcounting and multiple reports) (Source)
Average number of tornadoes per year from 1991-2010: 1253 (Source)
It’s not only the number of tornadoes on Sunday that’s unique for November. The location of the outbreak was also farther north than many November outbreaks. Take a look at the above comparing Sunday's storm reports to November climatology.
Cutting edge work is being done to create seasonal tornado outlooks as well as to understand how climate change could affect them in the coming decades. We included a few videos at the bottom which help explain where the science stands on the relationship between climate change, severe thunderstorms, and tornadoes.
Thanks to Harold Brooks with NOAA's National Severe Storms' Laboratory and Climate Central for supplying tornado climatology information.