Does El Niño intensity matter for California precipitation

The sensitivity of California precipitation to El Nino intensity is investigated by applying a multimodel ensemble of historical climate simulations to estimate how November–April precipitation probability distributions vary across three categorizations of El Nino intensity. Weak and moderate El Nino events fail to appreciably alter wet or dry risks across northern and central California, though odds for wet conditions increase across southern California during moderate El Nino. Significant increases in wet probabilities occur during strong El Nino events across the entire state. In California's main northern watershed regions, simulations indicate an 85% chance of greater than normal precipitation and a 50% probability of at least 125% of normal. Our results indicate that both the statewide average and the spatial distribution of California precipitation are sensitive to El Nino intensity. Forecasts of El Nino intensity would thus contribute to improved situational awareness for California water planning and related water resource impacts.