Last year's bottom side Derbyshire are on course for a huge win after a dramatic collapse by Northamptonshire.
Derbyshire were bowled out for 538 before Dominic Cork and Kevin Dean tore into Northamptonshire with the new ball to leave them on 25 for 7.
Seven players returned to the pavilion without troubling the scorers before Graeme Swann and Carl Greenidge helped the innings limp to 131. Following on, Mike Hussey and Mal Loye shared an unbroken stand of 100, but they were still glad when bad light halted play early.
Worcestershire's openers Anurag Singh (81) and Stephen Peters (71) put on 156 for the first wicket as the hosts looked like dwarfing Glamorgan's 286. But the Welshmen hit back, Darren Thomas claiming five wickets as Worcestershire fell away to 299 all out. Glamorgan were 38 without loss at the close.
Hampshire took a firm grip on events at the Rose Bowl. Kent paid for their inability to polish off the tail as James Hamblin's 50 inflated Hampshire's total to 345. In reply, Kent were bowled out for 118 and, following on, ended the day at 148 for 4.
Leicestershire are within sight of victory after Michael Bevan (146) and Darren Stevens (125) helped them reach 523. In reply, Warwickshire closed the day on 36 for 3.
Yorkshire, meanwhile, established a 261-run lead over Somerset at Taunton. The champions closed the day on 280 for 9 after Somerset earlier claimed a first-innings lead of 19.Reuse content