Arriving ahead of schedule, the first severe heat of the year rudely shoved its way into the Washington area yesterday, smothering man and beast under a blanket of humidity, haze and general meteorological misery.

The official high temperature hit 97 at National Airport at 3:29 p.m., the highest reading since early last September but two degrees short of the June 15 record of 99 set in 1964. National Weather Service forecasters predict more of the same today, but temperatures should moderate somewhat tomorrow and return to near normal levels in the mid-80s on Thursday and Friday.

The humidity also was awful yesterday: 100 percent in the early morning hours, dropping only to the 60-to-70-percent range in the afternoon.

As the sun beat down mercilessly yesterday, pedestrians in downtown Washington scurried for sparse patches of shade, tourists besieged ice cream vendors for relief along the Mall and kids in the suburbs took to neighborhood pools in droves. City pools didn't open until Saturday.

Most workers labored in the relative luxury of air-conditioned buildings or offices with fans and water coolers.

But not all. A small, scattered army of construction workers, parking lot attendants, street vendors, police officers and others who customarily work outside endured the sweltering heat with bedraggled resignation.

"You get used to it; you just learn to take it," said William Nash, 37, a laboror carrying 4-by-4 timbers at the Convention Center construction site at 11th and H streets NW. Sweat seeped out from under his sky-blue constructions helmet and poured down his face.

"Some people can't do it," he said of heavy outdoor summer work. "They start to feel like they're going to faint. It's a moneky [on their back] for them."

Nearby, D.C. police scooterman A. A. Issac walked out of the Trailways bus terminal and prepared to ride off into the city haze and heat. "The main thing is to try to keep moving on the scooter and try not to go into air-conditioned places too much," he said. "The switch from the heat makes you susceptible to colds and pneumonia."

At the Amoco service station at 13th and L streets NW, manager Eddie Tekeste sat in his tiny office, a table fan stirring the muggy air.

"There's no place to go," he said. "I just try to sit in front of the fan and drink from the water cooler" when customers don't require him to pump gas or change a tire. He said a half dozen cars had limped into his station by mid-afternoon with overheated radiators or broken water hoses.

Throughout the city, the heat slowed the pace of life. Pedestrians plodded along shimmering sidewalks. Commuters in shirtsleeves pressed themselves into narrow, shaded recesses of office buildings, waiting for buses to take them home.

Local utility companies reported unusually high electricity demand as air conditioning systems were cranked into full gear. The Potomac Electric Power Co., which serves the District, suburban Maryland and a small portion of Arlington, estimated its power plants were pumping out a peak energy load of 3,850,000 kilowatts in midafternoon, the highest level so far this year.

The only relief outside was a fitful breeze that gusted occasionally up to 21 miles an hour during the afternoon, according to the weather service.

Forecasters say today will be a carbon copy of yesterday: sunny, hot and humid with high temperatures ranging from 94 to 99. There is a 10 percent chance of rain.

The first real relief is not expected until about Thursday when a cold front from the west should bring some scattered rain and daytime temperatures in the mid-80s and nighttime readings in the mid-60s, about normal for this time of year.

Forecasters blamed the current unpleasantness on two related high-pressure systems off the Atlantic coast of Florida and over the southern Appalachians that have poured warm humid air into the Washington area. Those systems will be replaced soon by cooler air from the west, forecasters say.

Before yesterday's 97-degree reading, the official temperature had reached 90 or higher only three times this year -- twice earlier this month and once in May -- somewhat less than the average number of times for this period of the year. The weather has been unseasonably warm, however, because temperatures have failed to drop to normal nighttime lows in the 60s, remaining instead in the 70s.