Rain fell here yesterday for the ninth consecutive day, but weather forecasters indicated that Washington's protracted and unusual period of dampness, downpour and drizzle may be coming to an end.

With more than two inches of rain officially recorded here since Apr. 24, forecasters said they expect the dark clouds that have loomed overhead for more than a week to give way at last to blue skies and bright sunshine today.

The long string of wet, gray days in which Washington saw only sporadic periods of sunshine was blamed by the National Weather Service on a moisture-laden low-pressure system that lumbered into this area last month.

Instead of releasing rain and moving on as do the majority of such systems, this one didn't budge.

In the figures recorded at the official measuring station at National Airport, the results of this atmospheric aberration were these:

April 24, .15 inches of rain; April 25, a trace; April 26, .45 inches; April 27, .79 inches; April 28, .28 inches; April 29, .09 inches; April 30, .10 inches; and May 1, .19 inches.

By 11 p.m. last night the reading was .13 inches.

In some spots, forecaster Alan Rezek noted, rainfall amounts may have been larger or smaller.

In predicting that relief may at last be at hand for the rain-weary, forecasters pointed out that the lingering low-pressure system has slowly begun drifting out to the Atlantic Ocean.

While here, it produced little flooding, but, according to Sgt. Raymond Diegel of the D.C. Police traffic unit, spawned a rash of minor auto accidents.

It left the Potomac River brown and swollen and filled its waters with debris that could damage the hulls and propellers of boats, said Officer Wilfred Guillory of the police harbor unit.

Many persons have complained to the Weather Service that they have been unable to plant their gardens.