We've been operating under the belief that this year's El Niño winter, given the past few El Niño cycles, was unlikely to be as bad as last winter's historically wet, months-long string of atmospheric river storms. But we may need to batten down the hatches once again.

On Thursday, the national Climate Prediction Center put out a new report saying there is now a favorable chance that this year's El Niño being one of the strongest in decades — "a 54% chance of a 'historically strong' El Niño during the November-January season," to be precise. (November wasn't that rainy, so...)

The forecasters said this cycle is potentially going to be "one of the five strongest since 1950," though this still does not guarantee an unusually wet winter for the Bay Area — or a snowy one for the Sierra. And, historically, during all of the El Niño winters that California has seen since 1951, Southern California has received more rain than we have — 126% of normal, compared to an average of 109% of normal rainfall in NorCal across all El Niños.

As the Climate Prediction Center puts it, "While stronger El Niño events increase the likelihood of El Niño-related climate anomalies, it does not imply expected impacts will emerge in all locations or be of strong intensity."

We've known since May that an El Niño winter was coming, after a rare lineup of three La Niña seasons in a row. But it's hard to imagine that we could have a winter any rainier than the La Niña one we just had.

The last super-strong El Niño to wallop the Bay Area was the winter of '97/'98, and old-timers and natives will tell you that that was a depressingly long, and wet, rainy season that didn't give up until about April.

Photo: Osman Rana