The blue sky. Sunshine. Fifty-degree temperatures. Walking around without a coat.

It’ll all be a distant memory Wednesday morning as today’s springlike weather is blown out of the way by a winter storm looking so ominous forecasters have started using “the ‘B’ word.”

“B” as in “blizzard.”

Tonight the National Weather Service ramped up its forecast, issuing a blizzard warning to replace the hazardous weather prediction it had put out earlier in the day.

“It will be blizzard-like, especially along the lake shore,” said Jim Mitchell, National Weather Service meteorologist, this afternoon.

That “criteria” – for those who forgot what happened Jan. 6-8 – is when there is snow or blowing snow, winds sustained at 35 mph or higher, and visibilities reduced to a quarter mile or less for three straight hours.

Mitchell said to expect “white-out conditions” that will make travel nearly – or perhaps totally – impossibly during the later afternoon and early evening hours when the snow will be heaviest and winds will be gusting.

If it is a blizzard, the once-in-21-year event could have happened twice in three months in a winter most Buffalo-Niagara residents won’t soon forget. Blizzard or not, though, this storm – dubbed “Winter Storm Vulcan” by the Weather Channel – will be a humdinger.

The storm is projected to be widespread across the Niagara Frontier, where the heaviest of the snowfall is expected to fall.

Anywhere from 10 to 20 inches of snow is forecast in some of the heaviest areas, including the Buffalo metro area and points north. Slightly lesser amounts, but still more than a foot, is projected in other areas of the region.

It’s also going to be windy. Winds are expected to be blowing at 20 to 30 mph with gusts up to 45 mph near the Lake Ontario shoreline.

A winter storm warning for Western New York has been issued, effective from 2 a.m. Wednesday to 2 a.m. Thursday.

A little rain is expected tonight as temperatures drop down into the 30s, turning over to snow in the early morning hours. But, Mitchell warned, “it’s going to go downhill fast.”

The snow will be coming down hard and heavy starting in the late morning, accumulating quickly on roadways and making for dangerous travel conditions.

The warning from the weather service read: “Visibility will be dramatically reduced with deep snow cover on roadways during the peak of the storm.”

The snow will lighten up as the evening goes on.

The state Department of Transportation urged motorists to avoid travel Wednesday in the western part of the state “if possible.” Those who must drive should use “extreme caution.”

“Travel will be difficult, particularly during the afternoon commute,” the DOT said in statement Tuesday afternoon.

Electronic signs on highways were to display messages including “Severe Storm Warning” and “Expect Delays Wednesday.”

School districts were keeping a close eye on the forecast this afternoon but had yet to decide whether schools would be closed Wednesday. Many have used up or are closed to using up the snow days they’d budgeted for the school year.

“We will continue to monitor the weather. A decision will be communicated to WBEN by 5:30 a.m. tomorrow,” said Buffalo schools spokeswoman Elena Cala.

In other parts of the country, winter storm watches and warnings are also posted, including Chicago, where up to 8 inches is forecast with gusty winds through early Wednesday afternoon. Winter storm watches are also posted in Cleveland, Detroit and Erie, Pa.

Forecasters were studying computer models today to determine the most likely path of the low pressure system that’s fueling the storm. That will play a large role in the amount of snowfall and ferocity of the winds in Buffalo Niagara.

And in whether that “blizzard” designation becomes warranted.

Behind the storm, there will be another day or two in the icebox for Western New York, where temperatures ran below normal for nine of the first 10 days of the month.

Temperatures are forecast to drop to the single digits again by Wednesday night, rise to the mid-teens Thursday and then plunge back into the single digits again Thursday night.

The average monthly temperature heading into today – 19.4 degrees – was 11 degrees colder than normal. It was colder than both January and February’s monthly average and, at its current rate, is on pace to be the coldest March in Buffalo’s recorded weather history.

Friday’s high temperature, forecast to be about 37 degrees, will be closer to normal for the date.

Though it’s late in the season, it’s not unheard of to have wild winter weather in the month of March.

Here’s a snapshot of some other memorable March snowfalls:

• March 27, 2011: Spring brought 6.8 inches of snow.

• March 7-8, 2008: Two-day snowfall total of 21.3 inches.

• March 16, 2004: The 14.3 inches of snow was still a record for that day in March.

• March 13-14, 1993: Blizzard of ’93 dropped 17.5 inches of snow.

• March 2-3, 1976: Area ice storm caused $80 million damage.

• March 17, 1936: 19 inches of snow fell on St. Patrick’s Day.

News Staff Reporter Lou Michel contributed to this report.