Showers and thunderstorms developing ahead of a warm front in the central United States triggered tornadoes, hail and flash flooding in Oklahoma, eastern New Mexico and northern Texas. Baseball-size hail fell in Irion County, Tex., and winds gusted to 90 m.p.h. at Hobart, Okla. No injuries were reported. Flooding continued to chase hundreds from their homes in southern Ohio. Two teen-age Ohio girls drowned Tuesday after they waded in a rain-swollen creek near Chillicothe. Urban and small stream flood watches for much of eastern Pennsylvania, southern New Jersey and Delaware had been posted overnight.