How common are tornadoes along the Central Gulf Coast?

Maybe a little more common than you think.  Jeffrey Medlin, the Science and Operations Officer at the National Weather Service Forecast Office in Mobile,  recently completed a study of the return frequency of tornadoes with F1 (Fujita scale) and higher intensity along the Central Gulf Coast Region.  What he found might surprise you.  

Figure 1 - ≥ F1 Tornado Frequency by month for Southwest Alabama, interior
                 Southeast Mississippi, and extreme Northwest Florida.

Figure 1 depicts all F1 and greater tornadoes occurring in the Mobile Forecast Area from 1 Jan 1994 until 31 March 2007.  A review of the records shows 59 of them! He also produced a figure (figure 2) that shows their corresponding spatial distribution. Tropical cyclone mesocyclone-induced tornadoes account for 13.5% of the total number.  Outside of those, only two occur during the summer months.

Figure 2 - Tracks of all ≥ F1 Tornadoes (source SVRPLOT, NWS, Storm Prediction Center).

A few things to note:

• Note the bi-modal distribution with two distinct separate peaks (Nov and Mar). 
• November, by far, produces our greatest number of tornadoes (Nov=18) compared to our second runner up (March=12).
• The once "thought of" secondary peak is definitely the "primary peak" in this limited data sample.
• By the math,  59 total - (8 tropical) - (2 Summer) =  49 Cold Season Tornadoes [or 3.76 (G.T.E. F1) tornadoes / year]
• Of the 49 Cold Season Tornadoes, 11 are F2 or higher!
• Note that tornado path lengths are shorter (i.e. mostly touchdowns) closer to the coast, but they still occur.
• Although not shown in Figures 1 and 2, F0 tornadoes do impact people also.

So, if you think tornadoes are an extremely rare event around here, you might want to think again.