Northern and central parts of New South Wales are likely to gain close to a months worth of rain in 24 hours, while strong winds batter the state. A slow moving trough and developing low will trigger widespread 20-30mm rainfall totals across northern and central parts of New South Wales during the next 24 hours. For some areas in the north, this will be the biggest rainfall event in four months. The North West Slopes and Plains looks like being the focus of some of the heaviest rainfall, with the potential for some locations to see totals in the 30-50mm range. This region typically only gains around 20-40mm during the entire month of September. Gunnedah only gained about 40mm during winter, barely a third of the seasonal average, but could see this much by the time we reach the weekend. The heaviest rain will fall tonight into Friday morning, before pushing off the east coast. While the rain eases on Friday, the winds will strengthen as the low rapidly deepens off the New South Wales coast. The bitterly cold southerlies will be strongest along the ranges and coastal regions of the state. Sydney could see frequent gusts of 60-80km/h during Friday and Saturday morning.