A day after scientists announced that La Niña will be a reality this year — a claim that often brings the assumption a dry winter is ahead — a storm that the National Weather Service said will be a significant one continued to brew off the Pacific Coast and remained on track to reach the Bay Area early next week.
First, however, is expected to a mild, pleasant weekend with temperatures staying in the low 70s and high 60s in the hottest spots and sun peering in through scattered clouds.
If that sounds like ideal fall weather, winter nastiness isn’t trailing by much.
“This looks to be pretty heavy,” NWS meteorologist Dial Hoang said of the looming storm. “It’s a big system. Looking at the total rain forecast, we anticipate that there will be at least an inch across the Bay Area and there could be up to 2-3 inches in the mountains and higher elevations. . . . This is probably going to be a pretty notable early season storm.”
The storm is following a typical winter path as it descends from the Gulf of Alaska, meaning the North Bay likely will be the first part of the region to get the rain. But it will spread quickly, the weather service said, and areas of the region may be susceptible to flash flooding.
Also a slight possibility is thunder and lightning. The weather service said the low pressure that will bring that storm also will leave cold air aloft and could create some instability in the atmosphere Monday into Tuesday. Those thunder-and-lightning conditions are expected to be gone by Tuesday when the weather service said additional cold air behind the initial cold front will make its influence felt.
Hoang said the system also could bring some snow to the Lake Tahoe area at 6,500 or 7,000 feet. Temperatures are expected to reach the upper 50s in the region, so any snow is not expected to stick for long, according to the weather service.
The brewing storm comes even as federal scientists have announced that La Niña has begun and is expected to continue into winter. That phenomenon occurs when Pacific Ocean waters off South Africa are cooler than normal, leading to conventional wisdom that a dry winter is on its way.
That said, Golden Gate Weather Services meteorologist and Bay Area weather expert Jan Null said the phenomenon “is not a one-size-fits-all,” and said it is likely to have more of an effect on Southern California than the Bay Area.
Staff writer Paul Rogers contributed to this story.