So far tornado numbers across the United States are quite low for 2013.
According to the
Storm Prediction Center
, the year-to-date estimated total stands at 610 which is well below the 13 year average of 984 tornadoes.
The SPC says that in the past 13 years, the lowest tornado total into late August occurred in 2002 when only 579 tornadoes were counted.
So the question becomes why the low number this year and especially why the drop off from 2011 when 1,532 tornadoes were reported?
I posed this question to Meteorologist Chris Geelhart with the
Lincoln, IL National Weather Service office
Meteorologist Geelhart believes the cooler than average summer weather is playing a major role in the decrease in reported tornadoes. "The temperatures have been cooler than normal over the central part of the nation so far this summer running about 2 to 4 degrees below normal," Geelhart said.
Thunderstorms that develop tornadoes thrive on warm and moist air masses.
While we saw a very wet spring locally in the Tri-States and much of the region did as well, this summer in the Midwest we have often been under a much cooler and drier weather pattern.
As a result, the number of tornadic forming thunderstorms has been much lower.
The weather pattern has favored instead dry weather and cooler than average temperatures as high pressure systems have routinely funneled cooler and drier Canadian air into the Midwest.
So the question is, will the decreased number of tornadoes and the quiet weather pattern continue for the rest of 2013?
The odds tend to favor a quiet rest of the year.
In regards to long range weather forecasts for our region, Meteorologist Geelhart says, "Per the Climate Prediction web site, we are favored for having above average precipitation into the fall, but temperatures don't show one way or the other."
Another point to consider is that the most likely time of the year here in the Tri-States and much of the Midwest for seeing tornadoes has already passed. Tornadoes are generally most frequent in the spring and early summer months.
"Pretty quiet in the fall. Overall, our main tornado season is in the early part of the year," Meteorologist Geelhart said.
To find more information about tornado counts and study data from previous years
to go to the Storm Prediction Center's site for the topic.