California could be heading into a notably active winter, with a strengthening El Nin?o and a developing positive Indian Ocean Dipole potentially combining to favor a wetter pattern across the state.

A powerful El Nin?o is developing across the tropical Pacific, with unusually warm water spreading across the central and eastern Pacific. That warm tropical ocean can shift atmospheric circulation and strengthen the Pacific jet stream, helping steer more moisture toward the western United States.

Now, another ocean pattern is joining the mix.

The Indian Ocean Dipole is adding another piece to the puzzle

The Indian Ocean Dipole, or IOD, is an ocean-atmosphere pattern in the tropical Indian Ocean. Think of it as ENSO's neighbor: while El Nin?o measures temperature differences across the tropical Pacific, the IOD measures the temperature contrast between the western and eastern tropical Indian Ocean.

A positive IOD develops when waters in the western Indian Ocean become warmer than normal while waters near Indonesia and the eastern Indian Ocean become cooler.

That difference changes tropical rainfall and atmospheric circulation. Those changes can then send atmospheric waves into the jet stream, influencing weather patterns far beyond the Indian Ocean.

With a strong El Nin?o already developing across the Pacific, the additional tropical forcing from the Indian Ocean could help reinforce or modify the broader circulation pattern — potentially affecting where storms track, where Pacific moisture flows and where colder air is able to move south.

More Pacific moisture could target California

A strong El Nin?o typically favors a more active Pacific storm track and can increase the flow of moisture toward the southern and western United States.

The latest seasonal guidance shows a broad precipitation signal stretching from California and the Southwest across Texas, the Gulf Coast and toward the East Coast. For California, that raises the potential for more frequent Pacific storm systems during the winter.

But more precipitation does not automatically mean more snow statewide. Much will depend on temperatures and the elevation of the snow level when each storm arrives.

If the active Pacific storm track overlaps with periods of colder air, California's higher elevations could see repeated opportunities for significant snowfall. (Source: USA Today)

Story Date: August 19, 2026