Washington's first snowstorm of the 1980's brought a manageable two inches and little disruption to much of the area by late last night, but the snow threatened to accumulate to greater levels before ending today.

For much of the night, forecasters predicted accumulations of as much as 10 inches in spots -- a potentially paralyzing level. By 1 a.m., however, forecasters were reassessing predictions, amid indications that the storm might be diminishing.

Snow fell for much of the day here yesterday, whitening tree limbs and grassy plots, but it was not until the evening rush hour that snow began sticking to roads and motorists began skidding and colliding. Early this morning, icy patches were forming on many snow-soaked streets.

The number of traffic accidents reported to the District between 4 p.m. and 10:30 p.m. was 119, according to Officer Timothy R. Gibbs, about twice as many as the night before. But most of the accidents both in the city and in the suburbs were reported minor, and authorities across the area said conditions could have been far worse.

Road crews throughout the area began spreading chemicals and abrasives on roads and streets by midafternoon, and by late last night appeared content with their work thus far.

"Right now we're in pretty good shape," David Devine, a D.C. Transportation Department engineer said as midnight apporached and the area seemed to be enjoying a lull within the storm. "If it picks up and gets heavy," he added, "that's another story."

In Northern Virginia, "everything looks real fine," said John Chiles, of the state highway department. The "average sane driver" was traveling at 45 or 50 miles an hour with no trouble on main interstate highways, he said. But authorities around the area were mindful of forecasts made by both the National Weather Service and a private concern, calling for the heaviest accumluations to come after midnight.

Joel Myers, the president of Accu-Weather, a private firm that has contracts, with several Washington area jurisdictions, forecast 8 inches for this area, but said late developments might create a small zone in which accumulations could reach 12 to 15 inches.

Myers said that geographical band could include the Washington area. But he said that by early last night the storm, centered off the South Carolina coast, was still too far away from Washington to make an accurate prediction.

Myers did predict drifts up to three feet high today as winds were expected to steadily increase in velocity from 10 to 15 miles an hour last night to 25 miles an hour and occasionally higher today.

Temperatures are expected to remain in the high 20s to 32 throughout today, the forecasters said.

Forecasters initially predicted only about a four-inch accumulation in the Washington area, but National Weather Service forecaster Jerry Larue said the forecast was changed first to 4 to 6 inches and then 6 to 10 inches as the storm slowed and became more intense throughout the day.

With last February's devastating 18.7-inch snowfall firmly planted in the back of their minds, Washington area officials braced themselves for this winter's first storm with an elaborate array of costly new snow removal equipment and tons upon tons of sand and salt.

Stanley Ather, the District of Columbia's street maintenance engineer, said he has 300 snow plows, 50 more than last year, ready for street-clearing operations if the scope of the snowfall warrants it.

He said that drivers for 87 salt-spreading trucks were given assigned street routes to cover, an operation that initially encompossed 450 of the city's 1,300 miles of streets, including the most heavily traveled. Ather said, however, that District residents who find that their snow-covered streets have been missed by plows can call 727-5795 for assistance.

Metro, whose subway system was shut down by last February's storm, bought $50,000 worth of snow removal equipment, including 500 snow shovels; 3,000 bags of sodium nitrate, a salt-like substance; two snow plows for the front-end of diesel locomotives; five snow blowers and numerous other snow-blowing and removal contraptions.

Metro officials said some buses were delayed in traffic during last night's rush hour, but that "no major hangups" were reported and subway operations proceeded without incident.

Don Keith, the Virginia highway department's resident engineer in Fairfax, said he had 250 to 300 trucks and plows ready for operation and has stockpiled 26,490 tons of salt and 10,000 tons of sand. Other smaller jurisdictions had lesser amounts of abrasives waiting for winter's onslaught.

Even if accumulations reach the levels that have paralyzed the area in the past, authorities had one factor working in their favor last night in the effort to stave off catastrophe on wheels: Today is a Saturday and few commuters would be on the roads.

The snowfall during the day yesterday was slight enough that neither the federal nor District governments sent their workers home early. But Montgomery and Prince George's school systems were among many in Maryland and Virginia that were closed early.