Bay Area weather: How many more days is it going to rain?

A long-forgotten sound echoed across Northern California on Wednesday: the rustle of people digging through their closets to find umbrellas and raincoats.

The first significant storm in five weeks continued to douse the Bay Area with rain, bringing about 1 foot of snow to the Sierra at the higher elevations.

It wasn’t a deluge. In the 24 hours ending at 3 p.m. Wednesday, between a quarter inch and half an inch of rain had fallen on most Bay Area cities, with a more robust 2 inches in the Santa Cruz Mountains. But the rain calmed concerns that the state was heading into a severe dry spell, washed the soot and grit out of the air, and boosted conditions at Lake Tahoe area ski resorts.

In short, winter was back.

And more is on tap.

“On a scale of 1 to 10, what we just had is about a 2 or a 3,” said Jan Null, a meteorologist with Golden Gate Weather Services in Half Moon Bay. “On Saturday or Sunday we are going to see about a 6.”

Wet conditions were expected to give way to more mild, dry weather on Thursday and Friday, according to the National Weather Service.

After that, more rain is forecast late Saturday into Sunday, continuing through at least next Thursday.

“We have moved away from 65- to 75-degree days,” Null said. “Now we are getting cooler, unstable air in. It’s giving us these showery periods.”

The National Weather Service expects about half an inch for most Bay Area cities each day from Sunday to Tuesday. By next Thursday, 2 to 3 inches could fall across the region, boosting totals that are already near average in most cities.

“We had a wet period and a dry period,” Null said. “Average those out, you get kind of normal.”

California has been on a feast-or-famine winter so far. It started off very dry in November, then peaked between Christmas and the first week of January with several powerful atmospheric river storms that saved ski season, dumping 8 to 10 feet of snow on Sierra resorts, and generally soaking the entire state. Then the spigot shut off.

Until this Tuesday and Wednesday, no significant rain had fallen in the Bay Area since Jan. 5 — more than five weeks. The usual culprit was to blame: a ridge of high-pressure air off the West Coast that blocked incoming storms, diverting the jet stream north into Canada, where it picked up cold air and brought blizzards to the East Coast, leaving California with shorts-and-t-shirt weather while the rest of the country glowered in envy.

The dry spell, combined with warmer-than-normal temperatures, took a toll on the Sierra snowpack, the source of nearly one-third of California’s water supply.

On Jan. 6, it was 93% of its historical average. On Wednesday, it had fallen to 55%.

“Since the first week in January, we’ve seen effectively nothing,” said Andrew Schwartz, lead scientist at the UC Berkeley Central Sierra Snow Laboratory near Donner Summit. “It’s been dry and warm. Not only are we missing out on new snow, but the warm conditions have melted some of the snowpack.”

That isn’t as bad as it sounds, however.

Because the last three winters in a row have seen above-normal or normal precipitation — the first such streak in 25 years — reservoirs across California began the winter at higher levels than normal. Schwartz said there is no period in the records of his snow lab going back to 1946 when there were four normal or above-normal winters in a row.

“In terms of water availability, we’ve got plenty of water in the bank for now,” he said. “The problem comes if this winter peters out and we go into another dry year next year. But if we are going to have a dry winter this year, having full reservoirs is the way I’d want to do it.”

As of Wednesday, all of California’s major reservoirs were above their historical average for mid-February, and there was virtually no chance of summer water restrictions.

Shasta Lake, the state’s largest reservoir, near Redding, was 78% full or 116% of its historical average. Oroville Reservoir, the second-largest in Butte County, was 80% full, or 130% of normal. San Luis, between Gilroy and Los Banos, was 79% full, or 103% of average. And Diamond Valley, the largest reservoir in Southern California, in Riverside County, was 94% full or 128% of normal.

Several reservoirs, including Loch Lomond, the main water supply for the city of Santa Cruz, and Lake Cachuma, the largest reservoir in Santa Barbara County, were 100% full on Wednesday, with water running down their spillways.

Seasonal rainfall numbers in many parts of the state are in good shape.

As of Wednesday, San Jose was at 98% of normal rainfall for the winter season, which began on Oct. 1. Oakland was at 91%, San Francisco 83% and Santa Rosa 84%.

Cities farther south were showing above-average totals. The rain gauge in downtown Los Angeles was at 170% of normal, while San Diego was at 139% and Fresno was at 117%.

Schwartz said that the storms expected Sunday through most of next week should bring 1 to 4 feet of new snow across the Sierra, boosting the overall average, but not bringing it up to 100% of normal.

“We’re playing catch-up,” he said. “We aren’t going to recover completely, but it will help. This is going to be a really nice week to 10 days of storms.”