The Washington area, already staggering under a record-tying 99-degree swealter, was left punch-drunk and -- in many cases -- in the dark by a blinding thunderstorm that flooded downtown subways stations last night and dumped nearly 1 3/4 inches of rain on National Airport in an hour.

A power surge, apparently caused when lightning repeatedly struck the 15th Street offices of The Washington Post, twice shut down the editorial computer system.

The failure delayed publications of the paper's first edition approximately three hours, and caused some home delivery copies to be incomplete. There were only two editions of today's Post.

Urban flash floods forced the closing of the Southeat-Southwest Parkway in Virginia. Muddy water turned the intersection of Constitution Avenue and 14th Street Ellipse into a public pool, where Washington Monument tourists waded through waist-high water.

The monsoon-heavy rainfall overtaxed downtown sewer systems, sending cascades of water down into underground Metro stations "faster than our pumps could get it out," said spokeswoman Mary Buckley. The water came up over the electrified third rail, breaking the circuit and forcing Metro to shut down five of its stations for nearly four hours.

Metro Center, Union Station, Judiciary Square, Archives and Gallery Place stations were shut, although Metro Center was reopened about 9:30 p.m., Buckley said. Shuttle buses ran between Farragut North and the Rhode Island Avenue stations, and between L'Enfant Plaza and Gallery Place.

Power company officials said that actual outages in the area were limited and scattered. About 2,000 Virginia Power customers in Springfield, Arlington and Alexandria lost power when several circuits in Alexandria were apparently shorted during the rain.

About 10,000 Pepco users in Montgomery and Prince George's counties and Northeast and Northwest Washington also lost power, although most homes had power restored by 10 a.m. Pepco said the outages were caused by problems at two substations in Northwest Washington.

In addition, an unknown number of homes in the Capital Hill are had no telephone service last night, according to a C&P spokesman.

In the Trinidad area of Northeast, near Gallaudet College, flood waters raced through Capitol Avenue, Mt. Olivet Road, and West Virginia Avenue, rising "up to the shoulders," according to neighborhood resident Sylvine Backwell.

Blackwell, who lives on Capitol Avenue, said that from her house she could see D.C. fire and rescue workers using inflatable life rafts to bring residents out of flooded homes on Mt. Olivet Road. D.C. fire officials reported making dozens of similar "water rescues" from Benning Road to Bladensburg Road.

Around the corner on West Virginia, vendor Robert Jones-Bey watched "a parade of bottles floating down the street." Jones-Bey estimated that the water ran three or four feet high and swirled as much as five feet in places.

Yesterday's high, which equalled the 1936 record, came just after 4 p.m. National Weather Service meteorologist Barry Krecher said that the humidity, then 43 percent, gave a "humiture" reading -- a kind of reverse wind chill factor -- of 108 degrees.

The storm brought only limited relief from the heat. Between 6 and 7 p.m., temperatures at National Airport dropped from 94 degrees to 75 degrees, although by the end of the storm, temperatures had begun to climb again. The storm also dumped one-inch hail on the airport.

At 7 p.m., just before the deluge, the National Weather Service issued a severe thunderstorm and special marine warning urging area residents to "Seek shelter immediately!" However, there were no serious injuries.