After the constant tornado outbreaks of 2011, any severe weather season is going to seem pretty relaxed in comparison. However, save for the major tornado outbreak on March 2, 2012, the 2012 severe weather season has been pretty lacking.
Severe weather reports come in 3 categories -- tornado reports, large hail reports, and damaging wind reports. Tornado reports include both tornadoes and funnel clouds. Large hail is tricky: up until 2010, large hail was classified as 3/4" diameter or larger, and ever since they've been classified as hail 1.00" or larger. Damaging wind reports include any thunderstorm winds measure at 58 MPH or greater, or any thunderstorm winds that cause damage, regardless of speed.
Over the last 10 years, we've seen an average of 27184 severe weather reports per year, including 1387 tornado reports, 9417 large hail reports, and 13,338 damaging wind reports.
As we're only about halfway through the year, it wouldn't be fair to compare the 5 month 2012 severe weather season to an entire year's worth of tornadoes, hail, and wind. Through some Excel trickery, I've isolated the averages to include only January-May.
The average number of severe weather reports through the month of May turns out to about 10475. So far, we've only had 6,489 reports of severe weather.
The average number of tornado reports through the month of May is 687, which comes out to almost exactly what we've seen in 2012: 689.
The average number of hail reports over the same time period is 5971, and even though extremely large hail is constantly in the news recently, we've only had 3218 severe hail reports so far this year.
The average number of damaging wind reports over the last 5 months comes out to be 3873, and we've only had 2,582 severe weather reports up until now.
As noted at the beginning of the diary, most of this year's severe weather came in a few outbreaks which were able to bump the yearly average up to just slightly below average. The uptick in severe weather in January came in an early season severe weather outbreak across parts of the southern United States. The large spike in tornado/hail reports came in the devastating high-risk tornado outbreak on March 2nd across parts of Tennessee, Kentucky, Indiana, and Ohio.
Aside from that, even though we've had some pretty good severe weather events, the results weren't enough to bump us up to or over the averages for this period of the year so far.
If you like severe weather, the year is far from over. We usually see an uptick in damaging wind reports (which tend to be more numerous than hail or tornado reports) during the middle of the summer when intense mesoscale convective systems and derechos get going -- essentially, powerful lines of storms that tend to have very strong damaging winds.
For those of us going on severe weather fatigue, this is good news. Let's hope the below-average trend continues.