La Niña, the cooling of Pacific waters off the coast of Peru, causes worldwide impacts.
Usually, La Niña years produce a mild and dry winter for the Eastern U.S., something we did not see this year.
Corey Davis, the assistant State Climatologist for North Carolina, explains, “And now that we’re moving into the spring, we’re still not really seeing all that many signs of a La Niña pattern in the jet stream, in the atmosphere. It has been a little bit drier during March so far, but really nothing that we would attribute to a La Niña event.”
Even though the atmosphere has yet to show signs that we are in a La Niña, springtime can be more active for tornadoes.
“In North Carolina, we don’t see all that strong of a relationship between the ENSO phase and our severe weather activity,” Davis said. “La Niña springs do tend to be a little more active. A few more tornadoes for instance than El Niño years over the past 50 years.”
La Niña springs have averaged 15 tornadoes over the last 50 years, five more than El Niño years, but those numbers are skewed by major outbreaks like April 16, 2011.
Davis stressed the trend doesn’t mean this season will be a major one.
“When we’re talking about these long-term trends, and things like La Niña years having more outbreaks or El Niño having fewer, still just keep in mind that tornadoes are very fickle. They’re very finicky. Just having one pop up in the right spot can make it a very memorable, very damaging event,” Davis explained.
Our peak tornado season runs from March through May.