La Nina could bring us warmer, snowier winter
A developing La Nina pattern of cold surface water in the Pacific Ocean could mean a slightly warmer and slightly snowier winter for the Northland. That's the analysis of Northland winters during recent La Nina events by the National Weather Serv...
A developing La Nina pattern of cold surface water in the Pacific Ocean could mean a slightly warmer and slightly snowier winter for the Northland.
That's the analysis of Northland winters during recent La Nina events by the National Weather Service in Duluth.
The analysis found that La Nina events bring average winter temperatures about 0.29 degrees warmer than usual, along with about 7 inches more snow than usual.
That's much less dramatic than the effects of El Nino, which often causes unusually warm winters with very little snow in the Northland.
The warmer weather appears to be a new phenomenon, showing statistics don't always tell the same story. Occurrences of La Nina from the 1950s to the 1970s brought slightly colder winters to the Northland. But since then, La Nina has brought warmer winters.
Two La Nina events, in 1998-99 and 1999-2000, changed the average. The last major La Nina, in 1999-2000, saw temperatures 6.4 degrees above normal in Duluth, but snowfall 6.6 inches less than normal.
"With El Nino, it's very cut and dried for us. But La Nina is a little more subtle,'' said Carroll Christenson, warning coordination meteorologist for the National Weather Service in Duluth. "The last two major La Ninas turned out to be exceptionally warm for us, which really changed the overall numbers.''
The National Climate Prediction Center is forecasting a slight chance at a warmer than normal winter with no likely variation from normal precipitation.
Nationally, forecasters are saying La Nina is likely to get stronger.
"While we can't officially call it a La Nina yet, we expect that this pattern will continue to develop during the next three months, meeting the NOAA definition for a La Nina event later this year," said Mike Halpert, acting deputy director of the Climate Prediction Center in Camp Springs, Md., in a Thursday news release.
La Nina refers to the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific that occur every three to five years.
On average, Duluth receives about 90 inches of snow each winter.