La Niña, the cooler sibling of El Niño, has arrived.
And it could provide an additional boost to the already active Atlantic hurricane season, forecasters said, as well as extend the disastrous fire season in the West.
The La Niña climate pattern – a natural cycle marked by cooler-than-average ocean water in the central Pacific Ocean – is one of the main drivers of weather in the U.S. and around the world, especially during the late fall, winter and early spring.
Federal government forecasters from the National Oceanic and Atmospheric Administration announced La Niña's formation Thursday. NOAA said this year's La Niña (translated from Spanish as “little girl”) is likely to persist through the winter. It's the opposite pattern of El Niño (little boy), which features warmer-than-average ocean water.
“La Niña can contribute to an increase in Atlantic hurricane activity by weakening the wind shear over the Caribbean Sea and tropical Atlantic Basin, which enables storms to develop and intensify,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center.
“The potential for La Niña development was factored into our updated Atlantic hurricane season outlook issued in August,” he added.
In that outlook, forecasters predicted that as many as 25 storms could form in the Atlantic. Already, 17 have formed, including Hurricane Laura, which ravaged portions of southwestern Louisiana in August.
As for its impact on the western fires, La Niña tends to bring dry weather across portions of California and much of the Southwest. “We’re already in a bad position, and La Niña puts us in a situation where fire-weather conditions persist into November and possibly even December,” Ryan Truchelut, president of Weather Tiger LLC, told Bloomberg News. “It is exacerbating existing heat and drought issues.”
Wildfires in the West turn deadly: 'I never want to see California again'
Already, over half of the state of California is in a drought, according to Thursday's U.S. Drought Monitor.
A typical La Niña winter in the U.S. brings rain and snow to the Northwest and unusually dry conditions to most of the southern tier of the U.S., according to the prediction center. The Southeast and Mid-Atlantic also tend to see warmer-than-average temperatures during a La Niña winter.
Globally, La Niña often brings heavy rainfall to Indonesia, the Philippines, northern Australia and southern Africa.
The entire natural climate cycle is officially known as the El Niño – Southern Oscillation, a see-saw dance of warmer and cooler seawater in the central Pacific Ocean.
This article originally appeared on USA TODAY: La Niña forms, could worsen US fires, hurricane season