A B727 flight crew responded to a Terrain EGPWS warning while being vectored for an approach at ABE.

Narrative

At 3;000 FT [we were] cleared to intercept ILS 24. at Abe we received a Terrain Warning and then a Pull Up. I immediately started a climb and alert and lights went out and we broke out of clouds. We told ATC and then continued to intercept with confirmation from them also that we were clear of everything. Turbulence in area was probably a factor and information pages for airport warns of this possibility. We leveled off 300 to 400 FT above our cleared to intercept altitude; intercepted and had runway in site. I never used firewall power because we broke out so quickly.