Jim Gregg, a Rockville resident, left his home yesterday at 8:30 a.m. for nearby Potomac, where he hoped to enjoy part of the Kemper Open golf tournament.

But what should have been a quick trip took Gregg nearly three hours as he found himself part of the biggest traffic jam in the seven-year history of the championship.

For hundreds of would-be spectators and other area motorists, one of the spring's most beautiful days became a frustrating experience. "It was," Gregg said, "the pits."

Traffic was so snarled for the second day of the Kemper Open at the year-old Tournament Players Club at Avenel stadium course that tournament officials asked radio disc jockeys to tell listeners to stay away, and if they were already en route, to turn back. The tournament had previously been played at nearby Congressional Country Club.

"It's a zoo down there, nothing but a zoo," said Cathie Sterling, spokeswoman for the Montgomery County Police Department.

By midday, Metro Traffic Control was reporting backups of several miles in all directions surrounding the Potomac tourna- ment site. "It was atrocious," said anchor Kim Leslie.

Traffic was reportedly backed up on the Capital Beltway from near Tysons Corner to the River Road exit in Potomac.

That exit also was stacked up.

"This whole village is a madhouse," said Mike Mitchell of Mitch & Bill's Exxon station on River Road. "You can't get in, and you can't get out. I think it's a combination of it being a nice weekend -- it's Friday, and a lot of people are getting out of town -- and the golf thing."

On the other hand, for spectators who stuck it out until 8:30, when the last putt of the day and the last sliver of sun sank simultaneously, the ride home was above par. Montgomery County and state police reported little or no congestion along the Beltway and River Road in the hour after the swing shift.

Virtually cloudless and in the low 80s, yesterday was the first comfortable day in several. Forecasters predict that today's midday temperatures will hover around 80 and will be accompanied by light winds.

Golf officials blamed the traffic problems on heavy rains earlier in the week that waterlogged two-thirds of the 78 grassy acres reserved for parking, rendering them muddy and useless. On Thursday alone, 14 tow trucks worked continuously to extract cars that had become stuck in the mush.

Also, officials said that they had not been prepared for yesterday's mammoth crowd. Although tournament officials estimated the turnout at 35,000, Montgomery County Sgt. T.C. Lantzy said it was more like 60,000.

By either count, it was the largest Friday throng ever seen at the Kemper, said Charlie Brotman, a tournament spokesman. He said spectators who wish to view today's tournament play likely will not encounter troubles.

"We think it's going to be clear sailing," he said.

Additional parking areas are to be open, and more access lanes are to be provided for incoming traffic. Drivers exiting the Beltway are asked to avoid using River Road, detouring instead onto Seven Locks Road to MacArthur Boulevard and to Persimmon Tree Road, where signs are to direct them into the club.

Tournament Director Ben Brundred said he has encountered more than his share of troubles since pretournament play started last week. "Beginning last Saturday," he said, "when the tornado leveled all our tents, it has been a nightmare, but it looks like we've got everything back together."

Yesterday's traffic jams began at breakfast time, according to various reports.

Charles Neel of Springfield said he left his home at 9:40 a.m. and did not reach the golf course until 12:10. Asked if he was caught in traffic, he said: "You ain't kidding."

At 3:30 p.m., Sister Connie Craig of the School of the Holy Child on Bradley Boulevard still saw taillights on the horizon. "It has been bumper to bumper -- and I mean bumper to bumper -- since 7 this morning." Special correspondent Ben Gieser contributed to this report.