Sydneysiders woke up this morning to the strange sound of raindrops on their roofs. After a fortnight without seeing a single drop from the skies, this morning's 21mm would have been seen as a deluge to many. A strong high over the Bight combining with a low near New Zealand are to blame, directing an unstable southerly flow over Sydney. These southerly winds are particularly good as they direct cool, unstable and moisture-laden air from the Tasman Sea over the city, particularly the eastern suburbs. Sydney's Observatory Hill registered 21mm of rain in the 24 hours to 9am this morning, making it the wettest day since the 16th of April. Most of the rain occurred between the beach suburbs and the inner west with 32mm at Little Bay, 29mm at the Airport and Randwick. Along the northern beaches, North Manly registered 14mm, while 11mm fell in Mona Vale. So far, nearly half way into the month the city has only seen 21mm out of 80mm, which is the norm for this time of the year. This comes after a dry July, where the city only managed to register 17 percent of its July average with 16mm. The driest July the Harbour City has seen since 1995. Unfortunately, the western suburbs were not that fortunate with Bankstown only getting 1mm and between 2-4mm at around Parramatta and Hornsby. The far western suburbs, west of about Blacktown, were left dry as a bone with no need for rain coats. Showers are likely to redevelop this afternoon and evening right across the city but again should be heaviest on the coast. Showers will then ease overnight and clear tomorrow. Plenty of sunshine from Wednesday to about Saturday will allow daytime temperatures to gradually warm up before a complex low and trough bring more rain, wind and dangerous surf on Saturday night into Sunday morning and possibly the afternoon.