A plow clears snow on Sunrise Highway in Islip Terrace....

A plow clears snow on Sunrise Highway in Islip Terrace. (Feb. 10, 2010) Credit: Ed Betz

Long Island may get up to 20 inches of snow before the storm is over, the National Weather Service said Wednesday.

In general, 17 1/2 to 18 1/2 inches could fall in parts of Suffolk, including Islip, Upton and the northwest portion of the county. Nassau County could get as much as 15 1/2 inches along the North Shore.

But snow bands forming offshore and spiraling inward could run in repeat patterns in some areas, dumping larger amounts of snow, said meteorologist Ross Dickman.

PHOTOS: Click here to see the latest snowstorm photos from around LI

Many Long Islanders never left home in the first place as the giant storm bore down, turning Long Island into a haven of relative peace and quiet.

Heeding numerous warnings, commuters avoided the rails and roadways, and many schools, government offices and businesses simply shut their doors for the day.

All of the Island's 124 school districts were closed.

The weather service issued a rare blizzard warning for Long Island at 3:40 a.m. Wednesday and said it would remain in effect until 6 a.m. Thursday. Snow was predicted to continue until Thursday morning.

Forecasters said the storm would gain strength Wednesday afternoon, following a comparatively mild start during the morning rush hour.

Earlier Wednesday, the National Weather Service said the storm was expected to dump 10 to 16 inches here and strengthen into a blizzard before it was all over.

"This is the front end of the system," meteorologist Ross Dickman said. "The most significant part of the storm will come this afternoon," with the worst after 2 or 3 p.m., he said.

Forecasters warned of wind gusts of up to 40 mph. Downed trees, tree limbs and power lines and white-out conditions could make travel extremely dangerous, they said.

A high of 36 degrees was expected Wednesday, with lows in the mid-20s Wednesday night.

About 400 state Department of Transportation workers began toiling at 3 a.m. to clear snow off roads. Some 200 plows, loaders and other pieces of equipment were out Wednesday morning, spokeswoman Eileen Peters said.

"They'll just keep going until the storm is over," she said.

In New York City, an army of snowplows took to 6,300 miles of road, said a spokeswoman for the Department of Sanitation. The department deployed 2,100 workers in two 12-hour shifts, said the department's Kathy Dawkins. She said a total of 2,000 pieces of equipment, including 1,600 regular sanitation collection trucks, will have plows attached to handle the snow.

A stockpile of 153,000 tons of rock salt is also on hand to spread over the roads, she said.

Conditions on major Island highways had begun to deteriorate by 5 a.m. with a thin layer of slush and ice, even in the main lanes of the Long Island Expressway in Nassau and Suffolk.

The Long Island Rail Road has announced it will suspend service if accumulations reach 10 to 13 inches.

All flights at Long Island-MacArthur Airport were canceled Wednesday. Dozens of arrivals and departures at Kennedy and LaGuardia were also canceled. Expect most flights throughout the day to be canceled as conditions deteriorate.

Which, no doubt, is why the Weather Service had this bit of advice: "Do not travel."

New York City Mayor Michael Bloomberg urged drivers to leave their cars at home, warning they could become stranded or get into accidents. And then they'd end up saying of Bloomberg: "I should have listened to that guy," he said.

Forecasters were calling for a partly sunny day Thursday, but said we can expect stiff winds of 17 mph to 20 mph.

With Alfonso A. Castillo, Anthony M. DeStefano, Gary Dymski and Michael R. Ebert

PHOTOS: Latest snowstorm photos | Classic LI snowstorms, 1947-2009 | Animals in the snow!

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High school football highlights ... Bus camera ticket profits ... What's up on LI ... Heat with heart ... Get the latest news and more great videos at NewsdayTV

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