Storm systems fanned out across the Bay Area this week to dump some much-needed rain and deliver Lake Tahoe its first significant snowfall, just in time to open the winter season.

Kirkwood Mountain Resort, south of Lake Tahoe, reported 18 inches since the storms began Tuesday, while Northstar California Resort, which is northwest of the lake, saw 13 inches. Meanwhile, Heavenly Mountain Resort above South Lake Tahoe reported 6 inches of snow.

“People always say, ‘Oh, it’s early-season conditions, has the snow really started to fall yet?’” said Stephanie Myers, a spokeswoman for the resorts. “It’s absolutely coming down at Kirkwood right now.”

Holiday vacationers on the road toward Lake Tahoe learned this all too well, as motorists were forced to break out snow chains on Interstate 80 and Highway 50.

Forecasters with the National Weather Service expect the Bay Area’s wet and rainy conditions to subside a couple of days before returning early next week.

“We anticipate dry conditions to return for the remainder of the weekend,” said Roger Gass, a meteorologist with the National Weather Service.

A Winter Weather Advisory is in effect through midnight for elevations in the Sierra above 7000 ft. Periods of heavy snow could produce snow covered & slick roads, chain controls, & travel delays. If you can, wait until tomorrow to travel over the mountain! #CAwx pic.twitter.com/4irRdu5agO — NWS Sacramento (@NWSSacramento) November 24, 2018

Resorts at Squaw Valley and Alpine Meadows opened last week, but not without help from snow-making machines.

“We did hit our planned opening day last Friday, exclusively on machine-made snow,” spokeswoman Liesl Hepburn said. “Mother Nature’s kicking in some help now, and it’s looking positive for more storms as early as next week.”

Myers added that the natural snow combined with the artificially created powder can make for ideal skiing conditions.

Due to moderate to heavy snowfall Friday morning, the weather service issued a winter weather advisory for the Lake Tahoe region and elevations in the Sierra above 7,000 feet. Higher elevations — those above 8,000 feet — were forecast to see 8 to 14 inches of additional snow, while meteorologists expected 8 to 12 inches around the Tahoe basin.

Well that didn’t last long



⚠️ All I-80 eastbound traffic is being held at the chain control check point due to accidents and weather related conditions.#CAwx #CastlePeak pic.twitter.com/Y1ks5bENxf — Placer Sheriff (@PlacerSheriff) November 23, 2018

Eastbound traffic on Interstate 80 temporarily halted at a chain control checkpoint near Donner Summit on Friday afternoon because of the conditions, which brought 8 to 10 inches of snow along the I-80 corridor.

Jim Matthews, a meteorologist with the National Weather Service, said snow levels generally rose in high elevations throughout the afternoon and Lake Tahoe saw rainfall Friday night.

This week’s storms brought the first significant rainfall in the Bay Area since April. San Francisco has already received more than 1.5 inches of rain, and forecasters expected higher amounts in the North Bay, particularly the coastal mountains in northern Sonoma County.

Snow has returned to the Sierra! Some higher elevation have picked up 2 feet! #CAwx pic.twitter.com/WeIx51QI2I — NWS Sacramento (@NWSSacramento) November 23, 2018

Ashley McBride is a San Francisco Chronicle staff writer. Email: ashley.mcbride@sfchronicle.com Twitter: @ashleynmcb