"Extreme" is the word of the day for New South Wales, with record summer temperatures, fire danger and thunderstorms. A vigorous front is pushing its way through the state's south, forcing hot and dry northwesterly winds over the east and north. A Total Fire Ban has been in force since Monday due to the unfortunate mix of gusty winds, dry air and hot temperatures, the perfect recipe for dangerous bushfires. Many places across the North West Slopes and Plains and the Hunter have recorded a Fire Danger Rating in excess of 100, now known as "catastrophic". Storms have also had an impact, firing up in a line from Moree to Murrurundi at around 2pm. Any storms have the potential to cause damaging wind gusts and already Tamworth was buffeted by an 80km/h gust. Temperatures have soared as well. Narrabri Airport recorded its hottest December temperature in at least six years, hitting 43 degrees, 11 above average. Grafton also hit 43, making it the hottest December day in 19 years. Tomorrow the heat is expected to persist in northern NSW although the coast will see some relief thanks to an overnight southerly change.