How Does La Niña Impact Our Weather?
MINNEAPOLIS (WCCO) -- Minnesota already had its first brush with severe weather this month, and spring's just getting started.
Some meteorologists see a high chance of tornadoes for much of the country thanks to La Niña.
So how does the ocean phenomenon impact our weather? Good Question.
Jeff Wagner learned it begins well before our spring season kicks in.
It was a storm in early March carrying ominous clouds strong enough to yield a tornado warning, that thankfully doesn't foreshadow a more intense severe weather season for Minnesota, according the Minnesota Department of Natural Resources climatologists.
But according to Accuweather, a good portion of the Midwest from the North Star state's southern border down to the Gulf Coast could be in store for an active tornado season thanks to a weather pattern happening thousands of miles away: La Niña.
What is La Niña?
"[It's] a weather pattern that occurs over the Pacific Ocean where you have cooler sea surface temperatures that leads to more ridging in the Pacific," said Melissa Dye, meteorologist with the National Weather Service.
She went on to say that the cooler ocean water shifts the jet stream further north, often leading to a cooler and wetter winter for Minnesotans. Ironically, that didn't happen this winter.
How does it differ from El Niño?
"El Niño is the exact opposite. So you'll have warmer sea surface temperature in the eastern Pacific so we tend to be drier and warmer and the southeast United States is wetter and cooler," said Dye.
The concern with La Niña this year stems from 2011 when experts say the weather pattern played a role in a historic outbreak of deadly tornadoes in the U.S., most notably in Alabama in April and Joplin, Missouri in May.
One tornado hit north Minneapolis during the system in May, killing one person.
The impact of the tornado is still visible on the north side. Large trees with thick trunks were damaged and uprooted. Their now younger and skinnier replacements line streets along the tornado's path.
While La Niña could mean a higher frequency of tornadoes in the southern U.S., Dye said its impact isn't as strong around Minnesota and will weaken from winter to spring. And when tornadoes do happen, the blame isn't on those unique weather patterns.
"For example, June of 2010, you know that was a record-breaking tornado outbreak for Minnesota and that was neither La Niña or El Niño conditions," Dye said. "We're trying not to focus so much on La Niña or El Niño," adding that the NWS wants Minnesotans to be prepared for severe weather season no matter the weather pattern happening in the Pacific Ocean.
