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Why has the Pittsburgh area had so many tornadoes this month?

Meteorologist explains why Pittsburgh has seen so many tornadoes in May
Meteorologist explains why Pittsburgh has seen so many tornadoes in May 02:31

PITTSBURGH (KDKA) -- After two days of tornadoes in less than a week, the Pittsburgh area has already seen more than normal this year. So what's behind these outbreaks of severe weather? 

The Pittsburgh region averages only around six tornadoes per year. We've already had more than twice that number in 2024. Tornado season in western Pennsylvania usually peaks in June, but this year, severe weather started even earlier. 

Tornado strength is ranked by the Enhanced Fujita Scale, or EF scale, based on estimated wind speeds and related damage. Ninety-eight percent of tornadoes in the Pittsburgh region have historically been weaker EF0 and EF1s as opposed to stronger tornadoes. 

So far this year, the National Weather Service's Pittsburgh office confirmed 14 tornadoes in its coverage area, which includes nearby parts of Ohio and West Virginia. Six of those were in Pennsylvania. This marks the most confirmed tornadoes since 2021. Nine tornadoes have occurred in May, which is the most since 1985. Three tornadoes were ranked EF2s with winds from 111 to 135 miles per hour. That ties the entire 2021 season for total number of EF2-plus tornadoes. One more tornado that strong would mark the most since 1998. 

An EF2 tornado touched down in Peters Township on Saturday and the National Weather Service says winds peaked at 118 miles per hour.  Submitted

"(We're) well above average, twice the average. It's just been a busy start to the year with a tornado in February, April and, of course, a lot in May here," said Fred McMullen, a meteorologist with NWS Pittsburgh. 

The obvious question is why? Why so many tornadoes and why are they happening so early in the year? The lack of cold air this winter plays a big part.

"When you don't have those cold winters and you go into a warm season pretty quickly in spring, you get that moisture up here, you get the wind shear with the system," McMullen said. 

"Coming out of El Niño into a La Niña like we have going on now, we've seen several episodes like in June of 1998 where we had several rounds of severe weather. That's possibly on the table," McMullen added. 

Basically, the warmer-than-normal spring kickstarted severe weather about a month earlier than average, and there could be more on the way in June. 

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