An Impending La Niña Winter Approaches. Here's a Potential Impact on the United States.
A weak La Niña is predicted to develop prior to the season and may affect temperatures, precipitation, and even snowfall across the United States.
La Niña is a natural climate anomaly characterized by cooler-than-average sea temperatures in the equatorial Pacific. Its impact on the atmosphere is most significant during the winter months in the Northern Hemisphere, but its influence is weaker during the summer months.
Last winter was the hottest on record in the Lower 48 states due to the dominance of El Niño's counterpart, La Niña, alongside global warming due to fossil fuel pollution.
The prolonged heat prevented many severe snow events in the Northeast and Midwest, resulting in a winter snow deficit measured in feet.
While La Niña hasn't yet made an appearance, it has a 60% probability of emerging before November, according to the Climate Prediction Center. When it does appear, it's expected to stay throughout the winter and persist into at least the early spring of the following year.
La Niña and El Niño are not the only influencing factors on weather in a specific season or location, but they generally have a significant effect on winter weather in the United States, especially when they're strong.
Although it's unclear how strong La Niña will become, current predictions suggest a weaker one.
The strength of La Niña is essential; a stronger one can have a more consistent impact on weather, while a weaker one increases the likelihood that other weather and climate occurrences may affect weather patterns, according to Emily Becker, an atmospheric scientist from the University of Miami.
Earlier forecasts from the Climate Prediction Center indicate typical La Niña winter traits. These outlooks may change when the center releases its latest forecast on Thursday based on trends towards a weaker La Niña.
What might this winter bring?
No two La Niña winters are alike, but they often share common temperature and precipitation tendencies.
The behavior of the jet stream – a river of air that storms follow – often shifts north during a La Niña winter. This movement typically transfers stormy weather from the South to northern regions.
The Climate Prediction Center's latest winter outlook for December through February suggests this pattern, with the entire northern tier of the US expected to be wetter than normal, particularly in the Pacific Northwest, Midwest, and parts of the interior Northeast.
More precipitation cannot guarantee snowfall. Temperatures must be cold enough at elevations for snow to form and persist on the ground.
Weaker La Niña events often foster more snow in the Northeast, while stronger events can limit snowfall due to warmer temperatures rising up the East Coast.
If this year's La Niña remains comparatively weak, this outlook may change. However, the latest winter temperature forecasts from the Climate Prediction Center are not promising for snow enthusiasts in the Northeast.
The season is expected to be warmer than normal across almost the entire southern half of the US and a considerable portion of the East. This could result in wetter winter storms in certain Eastern regions instead of snow. However, the South and East are likely to experience drier and warmer than normal conditions, which could intensify drought conditions throughout the season.
Portions of the Midwest, Plains, and Rockies could experience temperatures close to normal this winter, while the Northwestern Pacific to the Dakotas might face cooler than normal temperatures.
The combination of wetter and cooler than normal conditions could result in more snow in the Pacific Northwest, an area essential for winter tourism and summer water supply.
Northern California is typically wetter during a La Niña winter, but the Climate Prediction Center's forecast anticipates the region to remain near normal this season. La Niña contributed to the extremely wet winter much of the state experienced from December 2022 to February 2023 and during the wet winter before that.
Southern California is expected to be drier and warmer than average – typical for La Niña. It's crucial for the region to have a soaking rain period in the coming months to curb the wildfire season. Without adequate rainfall, wildfires could continue to burn through the overabundance of fire fuels, like grasses or brush, available this year.
Given the text, here are two sentences that contain the word 'weather' and follow from the given context:
The behavior of the jet stream, a river of air that storms follow, often shifts north during a La Niña winter, which typically transfers stormy weather from the South to northern regions.
Weaker La Niña events often foster more snow in the Northeast, while stronger events can limit snowfall due to warmer temperatures rising up the East Coast, impacting the weather conditions in these regions.
