California Atmospheric River Forecast: ‘Big Changes’ in Storm Path Expected

Atmospheric rivers are forecast to “drench the West Coast” this winter, according to a recent meteorological report.
Last winter, the West Coast faced a slew of atmospheric rivers that caused devastating floods and landslides. The storms also brought a deluge of rain that supplemented California lakes and rivers, helping to eliminate the state’s drought. Meteorologists are again predicting a wet winter for the West Coast, according to an AccuWeather report published Monday, and meteorologists are warning of a “big change” expected in the Golden State by midseason.
Atmospheric rivers are a “long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics,” according to the National Oceanic and Atmospheric Administration.
Moisture in the Pacific Northwest will begin to increase in November and December, the report said, after California battled weeks of heat that sent temperatures soaring well past 100 degrees in some areas earlier this summer. California has endured heat-related weather warnings as recently as October.
Paul Pastelok, an AccuWeather senior meteorologist and long-range expert, told Newsweek that another strong atmospheric river winter could further improve California’s water situation, as drought is restricted to the state’s northeast and southeast corners.
Meteorologists forecast that the first half of winter will produce atmospheric rivers in the Pacific Northwest and Northern California before the storms trek inward over the Rocky Mountains. However, a “big change” is expected when 2025 arrives.
“Look for a potential shift in the storm track midwinter,” Pastelok said in the report.
The new weather pattern will create prime conditions for storms to shift southward and affect Central and Southern California. Meteorologists anticipate that January will be the wettest month of the year for Los Angeles and San Diego. Other cities throughout the Southwest will experience wet weather as the storms move inland.
Storm patterns will shift back to Northern California in February, the AccuWeather report predicted.
Frequent atmospheric rivers are more common during the El Niño climate pattern, which was underway this past winter. La Niña is forecast for this winter, although the climate pattern is expected to be weak, which could influence weather on the West Coast.
AccuWeather reported that even though La Niña climate patterns are not known for their frequent atmospheric rivers, a weak La Niña winter in 2022-23 produced nearly 40 atmospheric rivers across the Western U.S.
Pastelok told Newsweek he expects this incoming season to resemble 2022-23 in terms of atmospheric rivers, but the forecast could change if the water temperatures in the Pacific undergo a drastic change. If the warmest waters shift east, Pastelok warned, California could experience a dry, warm winter similar to the 2013-14 season.
Outside of California, AccuWeather is predicting a slightly warmer than normal winter across much of the rest of the U.S., although the Pacific Northwest and inland states like Idaho, Montana and Wyoming are expecting a cooler than normal winter.