Thunderstorms formed on the New South Wales ranges on Monday, some reaching the coast late in the day, bringing bursts of heavy rain. The heaviest falls were recorded in the north of the state. Gunnedah copped a dumping this afternoon, gaining more than 27mm in just a few hours. At the town's airport, 20mm was recorded, their highest daily total in nine months. Just southeast of Tamworth, Ogunbil picked up 29mm, also a nine month high. In central and southern parts of the state colder air gave storms a more damaging punch near the ranges and coast with stronger wind gusts and larger hail. A storm produced an 85km/h gust at Richmond in western Sydney. These storms will be potentially severe on Monday evening as they move east across Sydney, Central Coast and Illawarra. The storms should die late evening and move offshore in the early hours of Tuesday morning. Tuesday will be more stable across the state, with only a slight chance of afternoon storms in the northeast. Colder southwesterly winds will cause a few showers on the western slopes and ranges, but will be too dry to bring much cloud to coastal parts, let alone showers.