Tibetan Plateau warming linked to stronger California storms half a world away

A team of atmospheric scientists demonstrated that unusually warm land temperatures on the Tibetan Plateau during early winter can set off a chain of atmospheric changes that amplify atmospheric rivers hitting the U.S. West Coast later in the season. By analyzing observations, they identified a statistically significant link between plateau warmth and late-winter precipitation in California, a relationship not explained by oceanic patterns such as La Niña. Climate-model runs that used only sea-surface temperatures failed to capture the plateau heating or the resulting heavy rainfall, whereas models initialized with the observed plateau temperatures reproduced both phenomena.

The warming alters temperature gradients, disrupts the jet stream, and generates a Tibetan Plateau-Rocky Mountain wave train that destabilizes over the Pacific, strengthening atmospheric rivers. These findings suggest that monitoring plateau temperatures could improve forecasts of extreme rain and snow events, giving water managers and emergency planners more lead time. The research also notes that similar land-based signals influence weather elsewhere, such as the East Asian monsoon and the U.S. Southern Plains.