Rare December Severe Weather

Source: NOAA

Severe weather in December is relatively rare in the United States.  According to NOAA’s National Center for Environmental Information, the month of December averages the fewest number of tornadoes of any month with 24.  Despite this, there have been a few noteworthy December severe weather outbreaks.  Severe weather refers to a thunderstorm that contains any of the following: wind gusts of at least 58 mph, hail 1”/+ in diameter, or a tornado.

There was a significant tornado outbreak in Illinois this past Saturday, December 1, where more than three dozen tornadoes developed and caused extensive damage.  According to the U.S. Storm Prediction Center, the strongest tornado was an EF-3 tornado with winds of 155 mph in Christian County, IL.  It was the first EF-3 tornado to develop anywhere in the United States since July 28.  Fortunately, there weren’t any reported fatalities during this rare December tornado outbreak but some injuries were reported.  Based on NOAA data, this was the largest December tornado outbreak in Illinois state history.

More broadly, Saturday’s tornado outbreak was the largest in the United States during the month of December since 2015.  Between December 23 and December 28, 2015, a total of nearly 100 tornadoes were reported in the United States, primarily from the Ohio Valley to the Deep South.  The busiest severe weather day during this outbreak was December 23 when a total of 50 tornadoes occurred that led to four fatalities and 10 injuries.  Contributing to this severe weather was that December 2015 was the warmest December on record in many eastern cities, including Washington, D.C.

The deadliest U.S. tornado outbreak in December over the last 10 years occurred on December 23, 2014, when a total of 19 tornadoes developed in the Deep South that led to eight fatalities in Mississippi.  However, December’s largest single-day tornado outbreak in the last 10 years was on December 31, 2010, when a total of 66 tornadoes developed from Illinois to Mississippi.

The DC Metro Area has had only one tornado during the month of December over the last decade.  On December 1, 2010 a relatively weak and short-lived EF-0 tornado developed in Charles County, Maryland.  That was the third and final day of a severe weather outbreak that extended from the Deep South on November 28, 2010 to the Mid-Atlantic on December 1.  A total of 37 tornadoes developed, but no fatalities were reported.  

Some people may remember a more recent late-November severe weather outbreak between November 28 and November 30, 2016.  A total of 79 tornadoes developed, with an overall total of 348 severe weather reports (including severe wind and hail reports along with the confirmed tornadoes) from the Midwest to the southeastern United States.  Eight fatalities were reported during this outbreak.  NOAA’s Storm Prediction Center doesn’t expect any severe weather in the United States through tomorrow.