As the summer heat gradually subsides and temperatures settle in the 70s and 80s, the anticipation of seasonal change and the approaching winter gains momentum. This June, the National Oceanic and Atmospheric Administration (NOAA) officially declared the emergence of a El Niño, forecasting its strengthening in the northern hemisphere for the upcoming winter.
El Niño, along with its counterpart La Niña, are climatic phenomena capable of influencing temperature and precipitation patterns across the globe. During El Niño, warmer-than-average sea surface temperatures prevail in the Pacific Ocean. La Niña occurs when sea temperatures are cooler than usual in the central and eastern tropical Pacific Ocean. But their effects on weather are far from straightforward.
El Niños have shown both insignificant and profound impacts on rainfall patterns. Sometimes it has minimal effects, while other times its influence is substantial. Typically, Southern California witnesses increased rainfall during El Niño, whereas Northern California, Oregon, and Washington tend to experience drier conditions. During La Niña, atmospheric rivers are less pronounced on the West Coast, leading to drier conditions in the southern U.S. and wetter conditions in the north.
Predictions are circulating for the upcoming months, but the specifics remain uncertain. The prevailing sentiment indicates another rainy winter lies ahead. While not projected to be as intense as the previous year, it is expected to be far from dry. NOAA’s Climate Prediction Center releases three-month seasonal outlooks, and for the December-January-February period, Northern California is expected to have an equal chance of below or above normal precipitation.
El Niño’s influence on Northern California’s rainfall is not absolute. It can either bring increased rain or have a relatively minor impact. This is attributed to the phenomenon’s ability to shift storm tracks, often directing rainfall further south. The Farmers’ Almanac forecasts “wintry temps” for California and predicts a “snowy and wet winter” for the Pacific Northwest, which might extend to California.
NOAA predicts that temperatures in the region, ranging from Northern California to the Central Coast, will likely be above normal, with a stronger likelihood of above-normal temperatures in the north. The National Weather Service states that average temperatures from December to February for the Sacramento Executive Airport area range between approximately 47 and 51 degrees Fahrenheit. Normal precipitation for these months typically varies between 3.4 and 3.6 inches.
Regarding the possibility of extreme weather events like the earlier-year bomb cyclone that impacted Northern California, long-term predictions remain challenging. Specific events like these are hard to forecast more than about 10 days in advance. The evolving interplay of El Niño’s effects and the region’s complex meteorology make this upcoming winter’s exact nature a topic of ongoing speculation.