Forecasters said Saturday there is only a 40 percent chance that weather at the Kennedy Space Center will be satisfactory on Monday to launch space shuttle Columbia on a 10-day mission.

"It does not look all that good right now," said Terri Brasher, a spokeswoman for Air Force weather forecasters. She ticked off potential problems: poor visibility, a thick layer of clouds hanging low over the launch area and rain, but said "we remain optimistic."Ed Priselac, the space shuttle weather officer, said odds against a launch on Monday because of bad weather were 60 percent because of a front moving into Florida. Under NASA's inflexible rules, rain in the launch path or visibility less than seven miles would cause a launch to be scrubbed.

A postponement would be the fourth for Columbia, whose mission on this 33rd shuttle flight is to launch one satellite and to retrieve another. By doubling the time in space from the normal five days, NASA hopes to acquire data on the astronauts' long exposure to weightlessness as well as that of their ship.

The object is to modify Columbia, alone among the three shuttles, for long duration flights. A 16-day flight is planned for 1992, to be followed eventually by missions of up to 28 days.

NASA test conductor Mike Leinbach said the weather outlook would be evaluated late Sunday before workers start the flow of a half million gallons of liquid hydrogen and liquid oxygen into Columbia's fuel tanks.

Plans are for Columbia to catch up with the Long Duration Exposure Facility - a 30-foot long satellite launched from the shuttle in 1984 - move in front of it, and grapple it from above with the shuttle's robot arm.

The satellite was to have been retrieved after one year of exposing 57 experiments to the rigors of space. But budget problems and the Challenger disaster delayed the rescue mission until now.

Bill Kinard, chief scientist on the project, said the extra time in space has been a bonanza.

"Almost all the experiments have benefited," he said. "LDEF is a virtual treasure trove of science and technology information."

Included among the materials exposed to space are 121/2 million tomato seeds, which will be distributed among students from grade 5 through university levels to study genetic and other changes.

If not retrieved and brought back to Earth in Columbia's cargo bay, the satellite is expected to reenter the atmosphere and burn up by March 9. Its scientific mission would be wasted.