Southern California was in for “The Godzilla of all Nino’s” according to weather forecasters last year. According to the same forecasters Southern California was supposed get to drenched in torrential rain and experience widespread flooding.
So what happened, where is all the rain? The answer is that much of the rain Northern California has received in recent months is not significantly related to El Niño. Most of that precipitation — including this week’s storms hitting San Francisco — is coming from the typical winter weather pattern in California: cold storms from the northern Pacific Ocean, coming northwest of the state. Northern California — like the rest of the state — saw less rain during four years of drought. But this season is shaping up to be a wet year in the north, bringing more rain and snow than the region has seen in several years.
In Southern California the weather patterns differ form the North in that high pressure systems often develop and keep storms systems from coming into the region. This year these areas of high pressure have been especially persistent which has been keeping the rainfall to a minimum. Forecasters are hoping that this will soon change and that there’s still a chance of significant rain ahead. Although the forecast does not show any signs of major storms in the next week in the Southland, there appears to be a window of opportunity for significant precipitation to return shortly after that.
El Niño influences weather patterns because it can cause a subtropical jet stream — a narrow band of strong winds in the atmosphere that pushes storms west to east — to move from the jungles of southern Mexico and Central America to Southern California, Patzert said. In the strongest El Niño years, the jet stream can even marshal storms to cover Northern California.
The pattern suggests that “if there are any storms in the pipeline, they will be able to have a trajectory that can bring them into Southern California and it might allow them to maintain their strength. If this happens maybe we can still get some drought relief.