If you thought the weather of the last few days was spectacular and unusual and should be enjoyed because it can't last long, you were right.

The cool, dry air and moderate temperatures that made yesterday such a gem of a summer day are moving rapidly through the area, and by tonight will leave us once again with the muggy, hot weather Washingtonions have come to expect from their summers.

There is one more day to enjoy temperatures in the 80s combined with low humidity, but by tonight the weather of the past several days will be a memory.

Compounding that bad news, forecasters say its return is not a high probability. The long-term outlook for the rest of the summer is for higher-than-normal temperatures and more rain.

"It's going to be warmer and wetter. We're getting the best now," National Weather Service forecaster Jeff Bowman said yesterday. "You can enjoy this while it lasts . . . this weather is not expected to persist for the summer, not at all."

A cool front from the upper Great Lakes area, accompanied by a high pressure system, is responsible for the weather that drew area residents and tourists outside in droves yesterday. The front descended on this area last Tuesday, producing one better day after the other.

Yesterday was the kind of day for photographers to make those pictures that get on postcards and calendars, and with a string of rainy and muggy weekends behind them, area residents ventured outside with relish.

For some it was a day for remembering. The picnic scene at Greenbelt Lake in Prince George's County looked like the cover of a coloring book as Al and Sarah Messier from Gaithersburg made their first trip there in 20 years. Two canoes and a paddle boat skimmed away from the shore under a bright sun and a few puffy clouds.

"When you have children you do these kind of things, when you get older, you don't," said Sarah Messier. "It's beautiful."

At Burke Lake Park in Fairfax County, where thousands gathered, Gene Butts of Arlington and his grandson, Joseph Safko, pointed to their fishing catch of nine bluegill as they sat in the shade of the shore. "If we'd come last Sunday like we were going to we would have been miserable," said Safko.

Forecaster Bowman explained that a cold frontal passage from the northwest with cool Canadian breezes riding on its back arrived here last Tuesday after the stultifying, humid weather of the Fourth of July holiday caused by the Bermuda High. Rather than a pleasant experience as the name might suggest, the Bermuda High is "a stationary high pressure that meanders through here in a westerly direction." It is sometimes centered around Bermuda, and draws with it warm, humid air from the Gulf of Mexico into this area.

The cold front that gave it chase for a few days brought local temperatures down from daytime highs in the 90s and even set some record low temperatures. At Dulles International Airport, for example, temperatures dipped last week to a nighttime high in the upper 40s.

Like yesterday when the temperature reached a maximum of 85 degrees and the humidity was only 37 percent, today will bring mid-80s. Tomorrow temperatures are expected to rise to 90 and the return of the Bermuda High will bring higher humidity.

Translating meteorology into poetry, gather ye weather while ye may. After working here for a year Judy Hertz, 23, knew that yesterday was special. "It's gorgeous," she said as she showed her family from Massachusetts around the city.

And her mother,Ruth Hertz, knew what made it different from normal Washington summers. "It's dry, dry, dry!" she said.