REPORTER FILE PHOTO | A winter scene like the one above could be in the cards for the weekend as a major storm approaches the Island.

A “significant” winter storm is expected to dump between 12 and 20 inches of snow across Long Island, with the most snow expected on Shelter Island and the East End Friday into Saturday, according to forecasts by the National Weather Service, which issued a blizzard warning starting Friday.

Even higher amounts can accumulate on the East End due to isolated snow bands, weather officials said.

A mix of rain and occasional flurries had already begun to fall Friday morning, with about 2 to 4 inches of snow expected to accumulate during the daytime hours, according to NWS forecasts.

[Check back starting this afternoon for live coverage of the storm as it approaches the region].

But things are going to start picking up into the evening and worsen as the night goes on, when the blizzard will hit with heavy bands of snow and sustained winds between 30 and 40 mph — with gusts topping 60 mph — that will make travel dangerous and may cause power outages, officials said.

“This is a classic nor’easter,” said meteorologist David Stark, with the weather service station in Upton. ”All the ingredients that come together for nor’easter are there.”

The storm could cause electrical outages for over 100,000 customers on Long Island, according to a statement by National Grid.

Staff  at the Shelter Island  IGA reported no great run on food or supplies Friday morning,  but expected traffic would pick up in the afternoon. Both Island gas stations, Picozzi’s on Bridge Street and O’s on Route 114, had more customers than a normal Friday morning, but no  extensive lines of customers waiting to fill up.

Officials are warning people stay indoors as the full impact of the storm hits.

“The winds are going to be howling Friday night,” Mr. Stark said. “I wouldn’t recommend being on the road.”

The snow will continue through the night into Saturday morning, he said.

The east-northeastern winds may also cause beach erosion on the Shelter Island because of Friday night’s high tide, he added.

Weather officials have issued a flood warning for coastal areas across the region.

By Saturday afternoon, the storm will have moved out of the area and the high winds will die down over the weekend as temperatures rise above freezing, Mr. Stark said.

Residents are advised to avoid traveling during the storm due to the predicted hazardous conditions.

psquire@timesreview.com