Parts of western New South Wales can expect their biggest rain in four months as a long dry spell comes to an end. By this weekend, widespread 10 to 30 millimetres is likely over the western slopes and ranges. For some this will be their biggest rain since May and come close to their entire winter rainfall. This is good news for parts of the west, which have just slipped back into drought. For example, Gunnedah only gained about 40mm during winter, barely a third of the seasonal average. This week could bring more 20 to 30mm. This rain will come courtesy of two low pressure systems, one arriving on Tuesday and another later in the week. Parts of the coast will become as wet as the western slopes and ranges, but not until the end of the week. On Friday a low will form over the Tasman Sea and drive bursts of heavy rain and strong winds onto the coast for a few days. Sydney can expect to break its longest dry spell since January. The city gauge has not recorded any rain in the past 12 days, but should pick up a little on Tuesday night. Come Friday and the weekend, the city should have 25 to 50mm. It will be a return to winter after the warmest start to spring in five years.