We have seen the future, and it's spring.

Only a week after The Great Snowstorm, and with mounds of snow still piled on the sidewalks, a friendly high-pressure ridge along the East Coast swept the skies clear yesterday and nudged temperatures into the 50s.

According to Walter Greene of the National Weather Service, although overnight temperatures will drop into the 20s and low 30s, the unseasonably warm weather should continue through the Washington's Birthday holiday weekend.

"There's a kind of internal heating system within the high pressure system," Greene said, which has lifted Washington's temperature above the average for this date, 47 degrees. However, the record high of 74, set in 1939, puts Saturday's 53 degrees in the shade.

Still, spring is in the air, if you know where to look for it. The ice-cream cone returned yesterday to downtown streets, and so did the roller skate.

There were still vendors hawking fur-trimmed caps and Icelandic sweaters, but browsers seemed more receptive to the charms of punk-style sunglasses and glittering turquoise.

The new Washington Convention Center, which last weekend was locked up by the snow, this weekend was stocked with vacation dreams--recreation vehicles and boats and travel posters.

Store windows were filled with linen and hopsack, and the first official "whites" gleamed on the fashionable mannequins of Casual Corner. Boots were on sale, sandals just in, and stockings thinning to sheer.

"It was lovely--I walked with two friends all around Hains Point," Rose Sachs of Cleveland Park said.

Sachs, a member of the Potomac Appalachian Trail Club, said her club tries to get in a 5-to-6-mile hike every week, but last Sunday she could manage only a mile or so near her home.

Kramer Books above Dupont Circle still advertised a "Winter Reading Sale," but the circle's floating craps game has moved back outdoors, to the benches. One dog, wild with her first spring freedom, bounded down Connecticut Avenue with her leash in her teeth and her owner stumbling along at the other end. Another dog, normally cream-colored, was black with mud.

How warm was it?

Warm enough to take off your jacket--and your sweater. Warm enough to smell the wax on a new Jaguar sedan. Warm enough for a woman at an automatic bank teller machine to turn her face up for a 60-second sunbath.

Warm enough--almost--to melt away the last chill memories of The Great Snowstorm.