There have been nearly a dozen tornadoes across Upstate New York this year - including one that touched down at the Erie County Fairgrounds last month - and more are expected.
The conditions have been ripe for tornadoes across the region this summer, according to New York State Climatologist Mark Wysocki. Precipitation totals in the Buffalo area, year to date, are nearly 8 inches above normal. And Wysocki says all the moisture in the ground combined with warm air drives up the dew point.
"We like to have the dew point temperatures come up into about 60 degrees or higher in terms of value. The higher the dew point temperature the better chance we would have for the formation of tornadoes," Wysocki said.
The other key ingredient, he says, is a strong jet stream high above the earth which twists the warm moist air rising from the surface.
"That tends to set up what we call wind shear inside the thunderstorms that would develop. Or in the atmosphere in general. And that kind of twisting we find is a good indicator of tornado formations," Wysocki said.
And if a cold front moves through, he says, it just increases the chance that the tornadoes that do form would be more severe. Wysocki says the EF-2 tornado that damaged the Fairgrounds July 20th was unusual.
"We generally have the EF-0 and EF-1s. Those are the more weaker tornadoes. When you start getting into the 2s and 3s those are a little bit more of the unusuals. And 5s are the rare kind that we would see up here in the Northeast," Wysocki said.
So far this year there have been 11 confirmed tornadoes across upstate - just one above average. Even though tornado season drops off after August, Wysocki remains cautious.
"Since we are kind of in an unusual weather pattern and we have been for several years in which the averages are all kind of out the window. So even though we're at the end of the season it doesn't mean that we couldn't pop off a few more tornadoes into at least November," Wysocki said.