Thousands of persons enjoyed a delightful autumn day yesterday and lined Constitution Avenue NW to watch the third annual National Firefighters Parade under a warm sun and flawless sky.

Lights flashed, sirens screamed and bells clamored along the 10-block parade route, from Seventh Street to a reviewing stand at the Ellipse, as children bounced on their parents' laps and lounged in the sun-drenched grass on the side of the road.

About 100 fire and rescue vehicles from 60 jurisdictions paraded down the avenue. Firefighters waved and engine horns blared to the delight of onlookers.

"Marvelous," declared D.C. Fire Chief Theodore Coleman, who looked like a master of ceremonies as he stood on the reviewing stand saluting, waving and smiling at the crowd. "This is beautiful day."

Larry Wenzel, a forecaster for the National Weather Service, said yesterday's sunshine and high of 66 degrees at National Airport should be repeated today, with increasing cloudiness later this afternoon.

A high-pressure system centered over most of the eastern part of the country is responsible for the area's string of cool nights and pleasant days, Wenzel said. He added that there is a possibility of showers on Columbus Day tomorrow and on Tuesday as well.

Yesterday's parade and near-perfect weather also kicked off the beginning of Fire Prevention Week in the District, Coleman said. He hopes the parade and the increased visibility of the fire department "will make the citizens more aware of the devastating effects of uncontrolled fires."

Although there was a large number of the city's fire engines and emergency vehicles in the parade, the number of D.C. firefighters was noticeably slim. Many were out of uniform on the side of the route. A number of the firefighters said they did not want to participate in the parade in order to dramatize what they referred to as the growing rift between rank-and-file firefighters and Coleman's administration.

But most local fire departments used the parade to show off an impressive and colorful array of engines, ladder trucks, pumpers and other sophisticated firefighting equipment. Many were accompanied by floats, horse units, majorettes and high school marching bands that sent the pound of drums echoing over the Mall.

"I like all the fire engines," said Joey Jorgens, 5, who lives in Washington and came to the parade with his parents. Joey, who was sitting near a huge American flag suspended over Constitution Avenue from two ladder trucks, said he is a big fan of the fire department. He likes to play firefighter at home with his toy hose truck and two "hookey ladders."

Others have graduated to the real thing. Don Hurdle, a firefighter from Laurel and member of the Society for the Preservation and Appreciation of Antique Fire Apparatus, owns a 1954 Seagrave pumper that he bought for $2,500 and takes to parades.

His goal, Hurdle said, is "to keep old trucks from the scrap heap. Besides, everybody needs a toy."

The Beth Page, N.Y., Fire Department sent 15 firefighters and one engine 265 miles to take part in the festivities, said Pete Hance, a member of the Beth Page department.

"This is the second time we've been here and we'll be back year after year," Hance said, chugging a beer and smiling. "This is what you call a working vacation."