NWS Reno: Forecasting for the Sierra and Western Nevada Since 1905

SUMMARY POINTS: 1. EL NINO DOES NOT ALWAYS MEAN A WET WINTER FOR CALIFORNIA! Warming of the tropical Pacific Ocean with El Nino (or cooling with La Nina) is one of the only predictable features for seasonal (beyond 1-2 months) precipitation forecasting. Climate scientists know there are other features that affect winter precipitation; however, they are not predictable beyond a couple weeks or so. Depending on El Nino/La Nina alone can lead to large seasonal forecasting errors for California winter precipitation. 2. EL NINO NOT USUALLY MUCH HELP PREDICTING WINTER PRECIPITATION IN NORTHEAST CALIFORNIA AND WESTERN NEVADA. A weak-moderate El Nino is expected for the winter of 2018-2019. That strength El Nino does not provide much help for forecasting winter precipitation for the northern and central Sierra, northeast California, and western Nevada...with only the strongest El Nino events nudging chances for higher precipitation up slightly . Therefore, there are equal chances for abo...