WASHINGTON—Economic reports Thursday offered encouraging signals about U.S. factories, jobs and underlying demand in the economy ahead of a much-anticipated report on national output Friday.

Orders for durable goods—big-ticket items like refrigerators and bulldozers—grew 6.5% in June, the Commerce Department said. That marked the biggest jump in nearly three years. Separately, the nation’s trade deficit in goods narrowed 3.7% last month as exports rose sturdily and imports fell, the agency said.

Meanwhile,...