Here's how La Niña could affect the U.S. this winter

Topline

According to the National Weather Service, there is a high chance that La Niña will affect the U.S. this winter, a weather pattern characterized by warmer, drier conditions in most southern states with increased precipitation and cooler conditions in other regions.

Important facts

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Which regions could be hot and dry this winter?

NOAA expects drier conditions between November and January in the Southeast, Southwest and some states in the Great Plains and Mountain West, including Utah, Nevada, Colorado, Wyoming, New Mexico and Oklahoma. Above-average temperatures are also possible in the Southwest, Southeast and Mountain West, as well as the Midwest, Southern California and states along the East Coast.

Which regions could experience cool, wet weather?

The Pacific Northwest, Midwest and Northeast are expected to see above-average precipitation, according to NOAA. States with a higher chance of increased precipitation between November and January include Washington, Oregon, Idaho, Montana, Wisconsin, Michigan, Illinois, Indiana, Ohio, Pennsylvania and New York.

tangent

La Niña can also lead to more intense hurricane seasons in the Atlantic Ocean by increasing the area of ​​low vertical wind shear, increasing the number of hurricanes that develop and allowing stronger storms to form.

Surprising fact

Last winter – marked by El Niño – was the warmest on record in the USA. Temperatures in the lower 48 states were 5.4 degrees above average, according to NOAA. According to NOAA, several states recorded their warmest winters on record, including North Dakota, Minnesota, Iowa, Wisconsin, Michigan, New York, Vermont and New Hampshire.

Important background

The La Niña and El Niño weather patterns are caused by interactions between ocean surfaces and the atmosphere in the Pacific and occur approximately every three to five years, according to NOAA. Both weather patterns are part of the El Niño Southern Oscillation (ENSO), a climate phenomenon resulting from a shift in winds and sea surface temperatures over the Pacific, although NOAA and the National Weather Service note that their occurrence is unpredictable. The agency previously warned that climate change could increase the frequency of extreme El Niño and La Niña events, with increased precipitation and increasingly warmer temperatures. The two patterns do not always follow each other, although they do occur. A La Niña that follows an El Niño winter typically leads to warmer summers, and the National Weather Service warned earlier this year that La Niña would likely lead to record-breaking temperatures. The average La Niña pattern lasts about 15.4 months, while El Niño typically lasts 9.5 months, although the longest La Niña pattern ever lasted 37 months between 1973 and 1976.

Further reading

ForbesLa Niña could bring record-breaking heat to the U.S. this summer – what you need to knowFrom Cailey Gleeson