Tornado Climatology for the Huntsville Forecast Area.
Image of December 16th Limestone County Tornado Lightning image Wall Cloud image
1874 - January 2012
     Severe thunderstorms can bring with them many dangerous and costly impacts. Tornadoes can be the most deadly and destructive product of a severe thunderstorm . These powerful entities can reach wind speeds of at least 158 to over 200 mph in stronger tornadoes (EF-3 to EF-4 tornadoes).
     The monthly distribution of tornadoes is depicted above. The August maximum of Huntsville Forecast area tornado occurrences observed in Figure above is heavily biased by the Hurricane Danny outbreak on 08/16/1985, which produced 13 tornadoes. Thus the long term monthly climatology for tornadoes in Huntsville Forecast area is characterized by two periods of peak tornado activity: the spring months of March, April,and May, and the fall month of November. During these months, atmospheric conditions are favorable for tornado formation and development. These two periods are separated by an extended lull in activity from June through October. The exceptions during this quiet period are usually due to hurricane activity, as with Danny in August of 1985.


    The hourly distribution of tornadoes, in Central Standard Time, is depicted above. Most tornadoes in the Huntsville Forecast Area occurred between noon (1200) and Midnight (0000). The two most notable peak periods of activity occur in the early afternoon and evening hours. The highest level of activity is between 4 PM (1600) and 7 PM (1900). A second peak in activity is seen between Noon (1200) and 3:00 PM (1500). The most tornadoes during any single hour in the CWA occur between 5 PM (1700) and 6 PM (1800). A much smaller peak in activity occurs between 8 AM (0800) and noon (1200). Although much fewer tornadoes occur after midnight through 7:59 AM (0759), violent tornadoes (EF-3 to EF-5) can occur during this period, as was seen in February of 2008, when two EF-4 tornadoes struck northern Alabama.


    The yearly distribution of tornadoes is depicted above.  No well-defined pattern is noted when analyzing Figure 5, although a broad cyclic maximum of tornadoes occurs about every 10 to 15 years. Also, several years of peak tornadic activity of 10 or more tornadoes are evident. An active year for tornadic activity occurred in 1985 , when 17 tornadoes were verified in the Huntsville CWA. This included several F2 and a few F3 tornadoes. This outbreak was caused by the interaction of Hurricane Danny with a frontal boundary over the southeast U.S. There are many other maximums including the infamous 1974 outbreak (most of these tornadoes were due to the April 3, Super Outbreak).
     In 2006, the 32 tornadoes were verified, primarily F0 to F1 tornadoes, across the Huntsville WFO forecast area. 2008 was also a very active compared to the period between 1986 and 1996, with 26 tornadoes, of which two were EF-4's and three were EF-2's. This is the third highest tornado total for one year, falling behind only the 04/27/2011 and 04/03/1974 outbreaks.  Tornado activity overall has dropped this year, but the tornadoes that occurred remained strong. Tornado activity in 2010 started out early in January with one F2 tornado that affected the metropolitan area of Five Points in Huntsville. Through the April o 2010, WFO Huntsville has had one tornado somewhere in the forecast area every month except February. Our biggest event happened on 04/24/2010, when 4 tornadoes occurred in northeastern Alabama. In all, 2 EF3's, 1 EF4 (long track), and 1 EF2 comprised this event.  The largest tornado outbreak since the 1974 SuperOutbreak occurred in April 22, 2007, when 40 tornadoes were reported, many of which were strong to violent tornadoes (EF3-EF5's).  Some weaker tornadoes even occurred in February  and May of 2011 as well.

     The year of 2011 was the busiest tornado season on record with 50 confirmed tornado tracks that affected the Huntsville Forecast Area.  Most of these tornadoes (39), including 3 EF-5 and 4 EF-4 tornadoes, occurred during the 04/27/2011 outbreak.  In comparison during the April 4, 1974 Superoutbreak, 3 EF-5 and 3 EF-4 tornadoes occurred. Most of the rest of these tornadoes occurred on May 25-26th, 2011 (7), although a few more occurred in February and May.   

Special Thanks to the following people for use of the photographs on top of page: Dave Crowley at www.stormguy.com - Gust Front Picture, Warren Faidley at www.Weatherstock.com - Lightning Picture, and Sam Todd - Limestone Tornado Picture.

 


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