National Weather Service meteorologists predict an epic, potentially life-threatening winter storm will pound the region Tuesday afternoon and into Wednesday and cause whiteout conditions that could make travel — by plane, train, car and even on foot — “impossible.”

The Blizzard Warning — which goes into effect at 3 p.m. and lasts until 3 p.m. Wednesday — calls for the heaviest snowfall in more than a decade, at least a foot of snow in the Chicago area and more than 18 inches near Lake Michigan

The worst conditions are expected between 9 p.m. Tuesday and 5 a.m. Wednesday. Strong wind gusts topping 40 mph — up to 60 along the lake — and “intense” snow accumulation of 2 to 3 inches per hour could cause whiteout conditions that reduce visibility to less than 100 feet and create 4-foot snow drifts, meteorologist Richard Castro said.

Temperatures are expected to be in the teens with below-zero wind chills.

Gale-force northeasterly winds could create nearly 20-foot waves on Lake Michigan that raise coastal water levels, erode beaches and flood sections of Lake Shore Drive with water and ice. During the strongest part of the storm, “thundersnow” — thunder and lighting during a heavy snowfall — is possible, Castro said.

“Travel could become impossible and a danger in and of itself to be out in those conditions [Tuesday] night,” Castro said. “If possible, stay inside during the storm.”

But if you must venture out, it’s important to ready for the worst.

“You figure if you are out traveling and you end up going off the road, having to be rescued and you aren’t prepared for the conditions, things could be life threatening,” said Samuel Shea, another meterologist with the National Weather Service.

Because what’s expected is the kind of winter storm that in past years has strangled Chicago — and in 1979 was even blamed for the ouster of late Mayor Michael Bilandic.

Mayor Daley, who’s retiring from office this year, doesn’t have to worry about the potential political fallout of a poorly handled snow removal. But the mayor said he’s confident the city’s ready for the Blizzard of 2011, if it comes.

“We always have snow. It doesn’t matter. We know the snow is coming, and you get set,” he said. “We’re gonna do everything possible. Then, again, you go to the private sector with their trucks and things like that [to assist city crews with heavy snow removal]. That’s what you have to look at in this emergency. That’s what you have to do.”

Streets and Sanitation chief Tom Byrne said for the first time this winter he plans on putting out the city’s full fleet of 274 trucks, plus another 120 garbage trucks equipped with plows, on the street. There’s plenty — at least 220,000 pounds — of rock salt at the ready and more being delivered.

“We will work this storm with everything we have at our disposal,” Byrne said.

“Three inches an hour is quite a bit, and it’s a challenge, but the plan is ready and the plan is in place and we will attack that as we go.”

And if big waves force ice and water on Lake Shore Drive, Byrne says’ he’s got guys who can handle it.

“The drivers that are selected for the drive have been there for years,” Byrne said. “They know the dynamic.”

In anticipation of the storm, state House and Senate leaders gave themselves a snow day as a precaution, postponing planned legislative sessions for the first time since a 2006 ice storm paralyzed Springfield.

Some suburban school districts also plan to cancel classes. And Supreme Court Justice Sonia Sotomayor’s scheduled speech at Northwestern University’s law school set for Tuesday was cancelled.

Chicago Public School kids, not so much. Class will be in session Tuesday.

Parents were sent notes Monday advising them to monitor news reports and the system’s snow information center — which is online at cps.edu. CPS brass don’t expect to make a decision on whether to cancel classes Wednesday until late Tuesday at the earliest, spokeswoman Monique Bond said.

City officials and weather experts say Tuesday’s blizzard conditions put senior citizens and folks driving during the heavy storm at serious risk.

So check on your elderly neighbors, monitor weather reports and “use common sense,” Daley’s chief of staff Raymond Orozco said.