It looks like a warm and inviting spring day - and you ought to be advised that as luck would have it, the rowing season opens today on the Potomac River. There's not a finer sight in the sporting world than an eight-oared racing shell in action. Rowing has never been known as much of a spectator sport but, for the people who come to know it, it seems to turn into a passion. Even if you don't know the sport, it offers an occasion to spend as much of the morning as you please down by the river, out in the fresh air, thinking springtime thougths.

There will be plenty of time for uninterrupted conversation between races - it's very civilized sport - since there will undoubtedly be delays in lining up the shell for the starts. It's early in the season, the current is running uncomfortably fast, and there may be more of a breeze than the coaches would like. That interferes with the serious business of rowing - but not with the equally serious business of spectating.

George Washington University's shells take to the water against Stockton State at noon today from the Thompson Boat Center near the Watergate, where Virginia Avenue dead-ends. Georgetown University's women row against Washington College and St. Joseph's at 1:20 p.m., at the same place. Northern Virginia high school crews - both boys' and girls' - are competing along the Alexandria waterfront beginning at 8 a.m., with the varsity races around noon.The boat house is inside the Torpedo Factory complex, at the foot of Cameron Street. Bring your sun glasses.