The National Oceanic and Atmospheric Administration, the nation’s premier agency for weather and climate science, has been told by the Trump administration to prepare to lose another 1,000 workers, raising concerns that NOAA’s lifesaving forecasts might be hindered as hurricane and disaster season approaches.

The new dismissals would come in addition to the roughly 1,300 NOAA staff members who have already resigned or been laid off in recent weeks. The moves have alarmed scientists, meteorologists and others at the agency, which includes the National Weather Service. Some activities, including the launching of weather balloons, have already been suspended because of staffing shortages.

Together, the reductions would represent nearly 20 percent of NOAA’s approximately 13,000-member work force.

Managers within NOAA have been told to draw up proposals for layoffs and reorganizations to trim the agency’s staff by at least 1,000 people, according to eight people who requested anonymity because they weren’t authorized to discuss the plans publicly. The effort is part of the “reductions in force” that President Trump required as part of an executive order last month, as he and the billionaire Elon Musk make rapid, large-scale cuts to the federal bureaucracy.

NOAA managers have been asked to complete their proposals by Tuesday, one of the people said. The proposals are likely to involve eliminating some of the agency’s functions, though managers have received little guidance about which programs to prioritize for cutting.

Representatives for NOAA didn’t immediately respond to a request for comment on Saturday.

The recent employee departures have already affected NOAA’s operations in many realms: predicting hurricanes and tornadoes, overseeing fisheries and endangered species, monitoring the changes that humans are bringing about to Earth’s climate and ecosystems.