Much of New South Wales is experiencing another day of severe fire danger, as hot and windy conditions affect the state. A low pressure trough is moving across NSW today, bringing hot, dry and gusty westerlies and causing the mercury to climb into the 30s across much of the state. These high temperatures, low humidity and blustery winds are the key ingredients for bush fires and a total fire ban is in place from the Illawarra to the Far North Coast, and inland to the North Western and Upper Central West Plains fire areas. Many fires are still burning across eastern NSW and Sydney-siders have once again woken to hazy skies, thanks to the westerly winds dragging smoke across the basin from fires in the Blue Mountains and Hawkesbury areas. This led to hazardous air quality across eastern and northern Sydney and it wasn't until late morning that the northwesterly winds were strong enough to cause the smoke to start to disperse. During Sunday morning a Southerly Buster started moving up the coast, causing temperatures to drop. The southerly reached Ulladulla around 11am, causing the mercury to plummet by eight degrees in just half an hour. The Southerly Buster will reach Sydney in the mid-afternoon, then the central and north coasts during the evening with powerful winds ahead and with the change. Gale warnings are in place for much of the coast, while a severe weather warning for damaging winds is in place for the Southern Tablelands and ACT. While the cooler conditions will bring some relief, the powerful winds and a lack of rain will keep fire dangers elevated well into the evening. By Monday fire dangers will drop and temperatures across the state will be 10-15 degrees lower than today. The following days will see more mild conditions before heat rebuilds later in the working week.