Interest in the assassination of President John F. Kennedy, which has waxed and waned over the 40 years since his murder in Dallas, has reached an intensity this year unmatched in two decades.

Officials at The Sixth Floor Museum at Dealey Plaza have been dealing for nearly a year with media inquiries about Saturday's anniversary events. By Thursday afternoon, they had received 150 requests for press credentials.

There have been books, forums and television specials scheduled around the anniversary. A section of the plaza and the museum's parking lot were closed off beginning Thursday to cope with television news trucks.

But whether such attention will translate into large crowds on the plaza Saturday is anyone's guess.

"It's on a Saturday this year, so people don't have to work, and it follows up a buildup of media coverage. But I just don't know," said Jeff West, executive director of The Sixth Floor. "A lot may depend on the weather."

For the record, the National Weather Service predicts a partly cloudy and unseasonably warm day with highs in the upper 70s.

Up to 5,000 people have turned out on previous anniversaries. Crowds have been largest, by far, on the commemorations that end in 0 or 5 — most notably the 20th, 25th and 30th. The crowds have come despite the fact that — except for the dedication of a National Historic Landmark plaque in 1993 — there have been no official ceremonies in a generation.

Just before the 20th anniversary, the Kennedy family, wishing to celebrate the late president's life, requested that there be no official commemoration of his death, West said. The sanctioned events this year appear to have been designed to honor that request while acknowledging the public interest.

On Saturday, The Sixth Floor Museum will inaugurate an exhibit of photos by Kennedy White House photographer Jacques Lowe. That night, and again Sunday afternoon, the museum, in conjunction with the Dallas Symphony Orchestra, will present Leonard Bernstein's sprawling Mass at the Morton H. Meyerson Symphony Center.

Just after noon on Saturday, the rival Conspiracy Museum will stage a "Walk of Silence," accompanied by a drum unit, in which people will walk from the JFK Memorial to the National Historic Landmark plaque at Dealey Plaza shortly after noon CST.

But the main event is most likely to take place as it has every Nov. 22 — on a broad sweep of Dealey Plaza, where a crowd spontaneously gathers around midday of each anniversary date. There are no speeches. There is less emotion than curiosity. Television crews abound. Many people stand around watching other people stand around.