You've heard us talk about it before on the air, at school talks or at other events: May is usually our busiest month of the year for tornadoes here in Kansas. After chaotic months in May 2007 and 2008, we've managed only 9 tornadoes this month. That's not a typo: only 9!! For comparison's sake, the Greensburg storm in May 2007 produced 22 tornadoes in just 8 hours.
The graphic below shows all of the severe weather reports here in Kansas this month, with red dots representing tornado reports, blue dots for hail reports and green dots for high wind reports. (All graphics courtesy: Storm Prediction Center)
This got me thinking: what other months of May have been relatively quiet here in Kansas? I dove back into SPC's database to look. I discovered that while it is unusual, the low number of tornadoes is not without precedent. The following maps below show tornado touchdowns/paths each May from 1990 until 2008 (click on the map to enlarge):
What stands out to me are the months of May in 1992, 1994, 2000, 2005 and 2006. Each month had a low tornado count, especially 1994 and 1992 (only 2 and 4 tornadoes respectively!). What's interesting is that in each of these cases, the following month had a higher number of tornadoes reported. (Granted, it's not terribly difficult to surpass 2 tornadoes.)
Given the small data set (only 20 years), I can't make any strong conclusions on what June 2009 will be like tornado-wise. However, we know all too well that it's not the time to let your guard down.