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With dry La Niña conditions, persistent Western drought looms large in winter outlook

By Paul Duginski, Los Angeles Times on

Published in Weather News

LOS ANGELES - The forecast looks warm and continued dry this winter in California and the Southwest, which raises the disturbing prospect of a perpetual fire season.

More than 45% of the continental U.S. is experiencing drought right now, especially in the West. With a La Nina climate pattern well-established and expected to persist, the drought may expand and intensify in the southern part of the country during the winter ahead, the National Oceanic and Atmospheric Administration predicted.

The official outlook from NOAA's Climate Prediction Center, released Thursday, favors warmer, drier conditions across the Southern tier of the U.S. and cooler, wetter conditions in the north, consistent with an ongoing La Nina.

A La Nina occurs when the sea surface temperatures in the central and eastern equatorial Pacific are below average. Easterly winds over that region strengthen, and rainfall usually decreases over the central and eastern tropical Pacific and increases over the western Pacific, Indonesia and the Philippines. Forecasters now are expecting a strong La Nina with about an 85% chance of it persisting through the winter.

If this scenario unfolds, it would exacerbate drought conditions in Arizona, Colorado, Utah, New Mexico and California, and worsen the wildfire outlook for the remainder of 2020 and into 2021.

California is already experiencing its worst fire season on record. After a disappointing rainfall season, much of Northern California is classified as being in severe or extreme drought, according to the U.S. Drought Monitor released Thursday. Much of the rest of the state is in moderate drought or is abnormally dry.

 

To the east, big portions of Nevada, Utah, Arizona, New Mexico, Colorado and Texas are in extreme or exceptional drought.

The Southwest has been parched because of a disappointing monsoon season last year and a monsoon that was essentially a no-show this year.

Mike Halpert, deputy director of NOAA's Climate Prediction Center, told reporters in a briefing Thursday morning that forecasters don't know exactly why the 2020 Southwestern monsoon failed so spectacularly.

Arizona and California experienced their warmest April-to-September period in 126 years, according to the U.S. Drought Monitor. New Mexico and Nevada had their second-warmest such period. Utah and Arizona recorded their driest period ever during that same six-month stretch. New Mexico had its second-driest and Colorado had its third-driest. Arizona's newly established statewide precipitation record came in more than 2 inches drier that the previous record.

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