Weather forecasters yesterday predicted rain and warmer temperatures for the snowbound Washington area today, but they cautioned that residents should expect slushy slippery streets and sidewalks rather than any real relief from the heaviest snowstorm here in 57 years.

The rain is expected to wash away only part of Monday's 18.7 inches of snow that was measured officially at National Airport. High accumulations were recorded elsewhere in the area and most residents had an unexpected four-day weekend as the area was virtually shut down.

Both the National Weather Service and private weather foreeasters predicted rain and warmer temperatures this morning and afternoon and said there was a slight chance of sleet or freezing rain early today.

The temperature yesterday reached a high of 40 degrees at 4:15 p.m. and is expected to rise into the 40s today, the weather service said.

"I wouldn't expect any miraculous results for several days. There's too much snow," said Harold Hess, a National Weather Service forecaster.

As the Washington area began struggling toward its normal February pace, the federal government urged employes to report for work today, although officials said they would follow a liberal leave policy. Most local governments also said offices would be open today. Local school systems -- all of which shut down yesterday -- said they would remain closed today.

Major highways and thoroughfares were reported largely cleared of snow by yesterday afternoon throughout the metropolitan area, although many secondary roads and neighborhood streets remained impassable. The Metrobus system, which operated less than one third of its usual daily fleet yesterday, is expected to resume almost normal operations today, a Metro spokesman said. The subway will remain closed this morning.

Shops and department stores, which have reported losing millions of dollars of business as a result of the snowstorm's disruption of planned George Washington's Birthday sales, sought to open yesterday with mixed results.

Some retail outlets, including the Neiman-Marcus and Raleighs department stores at the Mazza Gallerie in Friendship Heights, reported doing a booming business yesterday. Other stores remained closed partly because employes could not get to work. Some banks and savings institutions opened briefly yesterday morning, but most closed by noon because of staff shortages and fears of robberies.

There were scattered incidents of looting and vandalism in Prince George's County, the District of Columbia and Alexandria. In Baltimore, police officials reported, there were more serious incidents of looting by people taking advantage of the difficulties caused by the snowstorm.

Business leaders said most stores, financial institutions and other commercial enterprises here would try to resume normal business today. Some stores have announced they will extend their George Washington's Birthday sales through next Sunday.

Yesterday's extended holiday provided a mixture of wintry good cheer, kindness, frustration and misfortune for Washingtonians who have endured one of the most snow-ridden Februaries in many years. Monday's snow brought the month's total to 30.6 inches -- not far short of the record February snowfall of 35.6 inches set in 1899.

In one of yesterday's small dramas, an 83-year-old Lanham couple ran out of heating oil. Maryland National Guard troops were dispatched in a jeep to help them out. Prince George's emergency workers and volunteers also drove District of Columbia policemen, doctors and nurses to the city to help maintain essential services.

There were notes of despair. "Lonesome is not a word in our business -- just say we don't have a lot of activity," said Clarence Huger, a special police officer on guard at the nearly deserted District Building yesterday. A newly married couple in their 20s, Robert and Janice Feldman, were stranded at National Airport, awaiting a much-delayed honeymoon trip to the Bahamas. "Where do I start?" Robert Feldman said as he began to recount his troubles.

National Airport, which had been closed Monday, opened one hour later than normal yesterday, although only one runway was in service. Dulles International Airport was open yesterday. Baltimore-Washington International opened at noon. An Amtrak spokesman said normal rail service is expected today after delays to up to two hours on some trains yesterday. Metroliners did not operate yesterday, the Amtrak spokesman said.

Monday's snowstorm also caused several deaths and hundreds of broken bones, sprains and other injuries.

By yesterday afternoon, Prince George's police had reported 37 looting incidents, many of them at the Eastover and Coral Hills shopping centers. Police said 11 arrests were made, and 30 state troopers in riot gear were called in last night to patrol county shopping centers. A smaller number of incidents of looting and windowbreaking was reported in the District, where police said supplementary patrols would be assigned to guard against further vandalism.

Two men were reported to have died, apparently of heart attacks, in Monday's snow storm, including Arthur Kuhl, 54, assistant secretary of the Senate. A 3-year-old Palmer Park girl died in a fire, although Prince George's County officials said she might have perished even if firefighters had not been delayed by deep snow.

Fairfax County police said yesterday that the 2-year-old son of Malia Guerrero was killed accidentally Monday evening as a family friend sought to dig out the child's mother's snowbound car. The auto's exhuast pipe was clogged with snow and the child, who had been left inside the car, died as a result of inhaling carbon monoxide fumes, police said.

Monday's near-blizzard was the heaviest single snowfall here since January 1922, when a 28-inch snowfall caused the collapse of the Knickerbocker Theater, in which 98 persons died and 130 were injured.

Forecasters for the National Weather Service and for AccuWeather Inc., a private Pennsylvaniabased company employed by several Washington area governments, said a rainstorm was heading toward Washington from the Gulf of Mexico, Louisiana and other southern states.

If the storm arrives here by late evening or early morning -- before temperatures rise above freezing -- it will begin as sleet or freezing rain and then change to rain during the day, they said. The snowstorm that struck much of the East Coast Monday and dumped 18.7 inches of snow over Washington has now blown out to the Atlantic Ocean, they said.

Monday's storm dropped 14.3 inches of snow on Philadelphia, where the weather was blamed for a collision on an elevated train line at a station in the northeastern part of the city. Ten persons were reported injured in the accident, which officials attributed to slippery rails.

In New Yok City, where about 12 inches of snow fell, the storm provided what Mayor Edward Koch termed "an opportunity to test our new snow emergency plan -- and the result gave us every reason to be pleased." The plan placed great emphasis on plowing remote sections of Queens.

The East Coast storm caused several fatal accidents, including the deaths of two young brother riding tandem on a bicycle, who police said were crushed by a snow plow Monday in Rockingham, N.C. In Georgia, six persons were reported to have died in weather-related incidents.