Hourly Forecast Detailed. 1  0am:The Lancaster, PA forecast for Mar 14 is 26 degrees and Heavy snow. 2  3am:The Lancaster, PA forecast for Mar 14 is 22 degrees and Blizzard. 3  6am:The Lancaster, PA forecast for Mar 14 is 22 degrees and Blizzard.  9am:The Lancaster, PA forecast for Mar 14 is 25 degrees and Ice pellets.