A La Niña occurs with cooler than normal water temperatures in the Equatorial Pacific Ocean, opposite of an El Niño which occurs with warmer than normal water temperatures. These climate phenomena influence weather patterns throughout the world and often lead to extreme weather events.
Last winter we had an El Niño which contributed to record-breaking rain and snowfall in some parts of the country, with record heat and drought in other parts of the country. Although La Niña is the opposite of El Niño, it also can bring weather extremes to parts of the country.
“La Niña is in place and will strengthen and persist through the winter months, giving us a better understanding of what to expect between December and February,” said Mike Halpert, deputy director of the Climate Prediction Center, a division of the National Weather Service.
Regional highlights include:
- Pacific Northwest: colder and wetter than average. La Niña often brings lower than average temperatures and increased mountain snow to the Pacific Northwest and western Montana during the winter months, which is good for the replenishment of water resources and winter recreation but can also lead to greater flooding and avalanche concerns;
- Southwest: warmer and drier than average. This will likely exacerbate drought conditions in these areas. All southern states are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;
- Northern Plains: colder and wetter than average. Likely to see increased storminess and flooding;
- Southern Plains, Gulf Coast States & Southeast: warmer and drier than average. This will likely exacerbate drought conditions in these areas. All southern states are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;
- Florida: drier than average, with an equal chance for above-, near-, or below-normal temperatures. Above normal wildfire conditions;
- Ohio and Tennessee Valleys: warmer and wetter than average. Likely to see increased storminess and flooding;
- Northeast and Mid-Atlantic: equal chances for above-, near-, or below-normal temperatures and precipitation. Winter weather for these regions is often driven not by La Niña but by weather patterns over the northern Atlantic Ocean and Arctic. These are often more short-term, and are generally predictable only a week or so in advance. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow;
- Central U.S.: equal chances of above-near-or below normal temperatures and precipitation;
- Hawaii: drier than normal through November, then wetter than normal December through February. Statewide, the current drought is expected to continue through the winter, with several locations remaining on track to become the driest year on record. Drought recovery is more likely on the smaller islands of Kauai and Molokai, and over the windward slopes of the Big Island and Maui;
- Alaska: odds favor colder than average temperatures with equal chances of above or below normal precipitation. The interior and southern portions of the state are currently drier than normal. A dry winter may set Alaska up for a greater chance of above normal wildfire conditions in the spring.
The National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. The National Weather Service operates the most advanced weather and flood warning and forecast system in the world. Visit online at www.weather.gov