At 2:45 p.m. yesterday, after 15 minutes of pointing to fancy maps and computer charts, David Olson faced the crowd in the brightly colored briefing room on the fourth floor of the World Weather Building and shrugged his shoulders.

"What all this really gets down to is what to expect here," he said. "And it's going to get darn cold."

This was hardly news to most of the 25 persons in the audience at the building in suburban Camp Springs, the home of the National Meteorological Center and one of the three largest weather forecasting facilities in the world. The men and computers at the center had been tracking the storm as it moved eastward all day.

But it added a sense of immediacy. For during most of this winter of bitter cold, the center in Camp Springs has been the calm in the eye of the storm.

There has been little sense of drama as bizzards have buffeted the Mideast, factories shut down and schools closed.

There is no world weather command room at the center. No giant man with pins on it, no barried weatherman running around, no phones ringing.

Instead, the temperature inside is 74 degrees and the pace is steady. Twenty-four hours a day, seven days a week the computers spit out an endless series of charts, graphs and printouts. They tell the weathermen the center and around the country what the weather is today and what, based on past patterns, it probably will be tommorrow. THe men are there to analyze what the computers tell them and try to improve on their forecast.

"We're mor less on constant schedule. We do the same thing whether the weather is good or bad," the deputy director, Harlan Saylor, said yesterday.

But this changes when the bad weather gets closer. "Anytime there's a threat of snow or a cold wave the briefing sessions are full.There's a personal interest," he said. "It peps things up."

Masaru Hamada had been tracking the storm since 7 a.m. He's in the center's precipitation division. That means he is a rain and snow specialist. He takes charts, temperatures and other data that the computers collect and draws up, twice a day, a national precipitation forecast that weathermen and local weather stations around the nation key off of.

There's a certain perverseness about the job. You learn to hope for bad weather. "Our people are hired to forecast rain and snowfall and they enjoy doing that," explained Hamada's boss, David Olson. "They like to have something to work with. They much prefer a busy day when there's more to do."

Yesterday's storm was "a classic weather front, the kind you read about in textboks but seldom see," said Hamada. It started in the Midwest and moved eastward with temperatures dropping dramatically. Those in Cleveland, for example, plummeted from 24 degrees above to 1 degree below zero in a two-hour period.

At 10 a.m. the temperature in Charleston, W. Va., stood at 41 degrees before the front hit it. At 1 p.m., just three hours later, it had dropped to 15 degrees. "It looks like the whole map is coming toward us," Hamada said as he traced the front moving towards Washington at 3:30 p.m.

Hamada was edgy. He wanted to get home before the cold weather hit. At the briefing, Oslon had said he expected the temperature to drop from a high of 48 degrees in early afternoon to 10 degrees by midnight. High winds and some precipitation were expected.

"Now here's something you can go home and tell your wives about," Olson had added, producing a special chart. It showed that the average temperature in Washington in January was 10:7 degrees below normal and that yesterday's 49 degrees was the high for the month.

But both Hamada and Olson had spent much of the day on problems far away from Washington . Olson had to prepare several special reports on what he said may "be the biggest weather story of the day - the potential for disasters from river ice breaking." By early afternoon Hamada was focusing not on Washington's problems but on New England, where he was prediting a four-inch snowfall.

The World Weather Center in Camp Springs is one of three such facilities. The other two are located in Moscow and in Melbourne, Australia. The center has revolutionized weather forecasting since World War II by using computers and charting the pattterns that govern the behavior of the atmosphere. The computer forecasts, modified by trained metteorologists are sent throughout the world and form the basis of most local weather forecasts.

The use of computers has improved the accuracy of forecasting about 25 per cent, according to deputy director Sailor.