Western Pacific

Scientists are tracking a massive Kelvin wave — a pulse of unusually warm water moving eastward along the equatorial Pacific — that is now headed toward the California coast. Such waves can raise ocean temperatures, affect marine life, and influence weather patterns, potentially strengthening El Niño conditions and altering rainfall forecasts for the western United States in the months ahead.

A series of East Pacific hurricanes is forecast to miss California, steering moisture into the interior Southwest instead, where heavy rain and flooding are possible. Once the tropical activity passes, forecasters expect a major, long-duration autumn heatwave to build over the region. Weather watchers in the western US are discussing the unusual combination of tropical moisture and extreme heat in the seasonal outlook.