Two highly advertised snowstorms skipped the Washington area yesterday but were followed by torrential rains last night that caused flooding, marooned cars and triggered power outages in some sections.

Sleet and freezing rain snapped tree limbs in Arlington and Fairfax counties, knocking out electric power in at least four areas.

Flooding rain on ice-locked roads in Fairfax and Montgomery counties stalled dozens of cars.

Though little snow fell during the day, the rain poured throughout the evening, bringing the month's total to more than three inches so far, well above the normal January total to 2.62 inches.

The Virginia Electric and Power Co. reported power outages on Rte. 236 in the Pickett Road area, on Rte. 7 between Vienna and Reston, in the McLean-Falls Church area and in an area adjacent to Fairfax Hospital. The hospital maintained its power, but Vepco said about 700 residents in the surrounding area lost their power around 6:15 p.m.

More than 4,000 residents were affected by the other outages.

Montgomery County, Maryland State Police reported that access ramps and underpasses on the Capital Beltway near Rockville were flooded last night, disabling numerous vehicles. Similar flooding was reported on Rtes. 7 and 123 in suburban Virginia.

In many cases, ice along the edges of the roadways trapped the falling rain, creating pools of standing water that stalled vehicles.

Precipitation of all kinds - sleet, freezing rain, just plain rain and even some snow - fell throughout the day.

But the big snows predicted by the National Weather Service never came, leaving most area schools open to the disappointment of thousands of children and perplexing the populace in general.

The big snows brushed only the westernmost reaches of the suburbs, where three to five inches accumulated.

The National Weather Service had originally called for four to eight inches for the area. By the end of the day, however, less than one inch had been recorded at the official measuring station at Washington National Airport.

What happened? Weather service spokesman Chet Hendrickson said the brunt of one of two storms expected here moved farther north during Monday night than forecasters had predicted. A second, back-to-back storm also dumped much of its snow elsewhere, he said, before it slipped into a kind of watery coma and died.

School children, buoyed by the confident assurances of television and newspaper forecasts, had gone to bed Monday night anticipating a raging snowstorm and closed schools yesterday.

Likewise, thousands of commuters expected the worst as some drove to work earlier than usual and others apparently decided to stay home. Morning rush-hour traffic was reported lighter than normal on many roads. Spot checks of government agencies indicated normal to slightly above normal absenteeism during the day.

As it turned out, snow fell fitfully during the morning but gradually turned to sleet or rain, making for one of January's drearier days.

Schoolage children in the District of Columbia and Prince George's County were especially disappointed when they found schools open since they had hoped to add another day to a four-day weekend. Schools were closed last Friday because of snow and again Monday after the weekend in observance of the birthday of civil rights leader Martin Luther King Jr.

"I thought it was stupid to have us come in (yesterday) since snow was on the ground," said 14-year-old Beth Ferguson, a ninth grader at Elizabeth Seton High School in Bladensburg. "I wanted to play outside in the snow."

With the predictions for heavy snow, road-salting crews in both the city and the suburbs went to work Monday night, so that by morning all major commuter routes were clear of the small amounts of snow and ice that had accumulated.

Crews were cut back during the day as the snow turned to rain. The temperature rose to 36 degrees at National Airport in the afternoon. As night came, however, temperatures began to fall to the freezing mark in the suburbs, causing ice to form on trees, electric lines and roads.

Weather service spokesman Hendrickson, acknowledging that forecasters had overstimated the snowfall for the Washington area, said predicting weather patterns is a difficult and imprecise science.

"You should try this job once in a while," he said. "As the Indians used to say: 'Never judge another man until you've walked in his moccasions.'"

He said he and other forecasters at the weather service still are not certain what caused their forecast to misfire.

"There was a lot of snow moving directly toward D.C. from West Virginia (Monday night) and then it suddenly shifted northward into Pennsylvania and northern Maryland," Hendrickson said.

"All indications were it was coming straight at us," he said, "but for some reason, it was pushed to the north."

A low pressure area centered over the Georgia coast, he said, was expected to bring a second snowstorm on the heels of the first one.

But again, he said, "the snow line was pushed farther north than we had expected and it hit principally Pennsylvania and northern Maryland."

He said the weather service predicts specific conditions such as snow or rain within fairly close geographic ranges. "So if we forecast rain in one place and snow in another, and the storm system moves 50 miles from where we said it would be, it can throw the whole forecast off," he said.

By nightfall yesterday, Hendrickson said, a total of about one inch of snow had accumulated at National Airport, the metropolitan area. Snow totaled one of the warmest and driest parts of one to two inches south and east of the city, he said, and two of three inches west and north.

With the northward movement of the snowstorms, most of the precipitation during the day here turned out to be sleet, rain or freezing rain. The weather service defines sleet as precipitation that is frozen as it falls to the ground as dinstinct from freezing rain, which is in liquid form as it falls but turns to ice after it hits the ground.

Though most schools in the immediate Washington area were open yesterday, some including those in Prince George's, Montgomery and Fairfax counties closed early in the afternoon.

Schools in outlying Loudoun, Frederick and Howard counties, where snow accumulations were greater, closed for the entire day.

Elsewhere in the nation, snow and heavy rains were the rule. Snow battered much of the Midwest. Temperatures fell to 12 degrees below zero at Grand Forks, N.D.