The forecast remained on track for a powerful and potentially historic winter storm, the National Weather Service in Duluth said late Friday. Heavy snow accumulations of 1-2 inches per hour are anticipated to be accompanied by dangerous travel conditions and gale-force winds on Lake Superior.

A blizzard warning for areas around Duluth, the North Shore and Northwestern Wisconsin ratcheted up throughout Friday, which began with weekend winter storm watches.

Widespread snow accumulation of 10 inches or more is likely, with threats of up to 20 or more inches in some places. Blizzard conditions were largely to be found within 5 to 10 miles inland of Lake Superior, the weather service said.

Confidence was high to expect a lot of snow between the Twin Ports and Brainerd to the west, as well as Northwestern Wisconsin, said Bryan Howell, an NWS meteorologist.

"Once you get up to the north, along the north of the Iron Range, confidence decreases quickly," Howell said.

The weather service reported that the weekend's storm had the potential to become a "top-10 highest two-day snowfall total in recorded history for Duluth," and top-15 for Ashland and Brainerd.

"The city of Duluth is preparing for the second snow storm in a week to hit the Twin Ports," city officials said via Facebook post. "(P)lows are prepared for this next storm. We appreciate residents' patience as plows will work to remove snow as quickly as possible. As a reminder, plows will focus on keeping main roads clear first before moving into residential areas."

Blizzard warnings were issued Friday for southern St. Louis County, Carlton County and along Lake Superior in Lake County from Saturday morning to Sunday morning. Winds could be up to 40 mph and visibility would be only a 1/4-mile or less, the weather service reported.

Central St. Louis County and Douglas County, as well as much of Northwestern Wisconsin and Northeastern Minnesota, were upgraded from a winter storm watch as the data consolidated throughout the day.

The weather service reported that snowfall should be highest along the North Shore between Duluth and Silver Bay as well as in northeastern Ashland County, with between 14 and 22 inches expected.

Lakeshore flooding was expected in Superior and Duluth, especially Canal Park, with waves estimated to be between 10 and 18 feet. Flooding was most likely to happen between Saturday and Sunday afternoons.

"City staff would like to remind the public not to drive through standing water, and keep a safe distance from the shoreline," the city of Duluth's release said.

Live cams are available to see conditions in the harbor and the lakeshore area at visitduluth.com/livecam/.

Conditions were expected to be the worst Saturday afternoon and evening. The weather service reported that snowfall should end around 3 p.m. Sunday in central and southern St. Louis and Lake counties, Carlton County and most of Douglas County.

The blizzard conditions will make travel dangerous, if not impossible, Howell said.

"With this being such a big storm I wouldn't be surprised if we're into late Sunday afternoon, Sunday night before driving conditions start to improve," Howell said, and that could be true for areas outside of the blizzard warning as well.

"There's still going to be the potential for a lot of drifting and blowing snow elsewhere," Howell said. "It's going to be hard to keep up with the plowing, I think."

Freezing drizzle in northwest Wisconsin could create a light glaze of ice.

The Duluth Transit Authority encouraged its regular DTA passengers to get any errands done Friday before the storm hit over the weekend. The expected blizzard conditions could lead to possible service limitations, said DTA director of marketing David Clark.

During limited services, the DTA runs an emergency mainline route that avoids trips up the hill and runs between the Lakeside and New Duluth neighborhoods.

The worst-case scenario, Clark said, is short-term cancellations of all routes, including the emergency mainline route.

"We really are placing the safety of the general public and our team first," Clark said. "Given that we live in such a geographically weather challenging area, it's not something we like to do, sometimes we just need to make that call to protect the safety of the public."

The DTA will release updates on its Facebook and Twitter accounts as well as at DuluthTransit.com.