Hot and dry northerly winds are sending the mercury soaring across South Australia today, leading to severe fire dangers in some areas of the state. A weakening of the monsoon trough over the past fortnight has seen heat build over the nation's interior. This heat is being directed into South Australia today ahead of an approaching low pressure trough. A severe fire danger rating and total fire ban has been issued today for the West Coast, North West Pastoral, Eastern Eyre Peninsula, Mount Lofty Ranges and Lower South East districts. This includes places like the Adelaide Hills, Whyalla, Ceduna and Mount Gambier. The remainder of the state has a very high fire danger rating today. Temperatures reached 39 degrees in Tarcoola and Wudinna before 1pm and 36 in Adelaide, seven above average for the state's capital. For most of the state, including Adelaide, this is the hottest day in a fortnight. The trough will bring a cooler change to all southern parts of the state by tonight, although the hot air mass will linger over northern parts of the state for at least the next week.