A cool change has hit the south western coastal parts of Victoria, but won't get to northern parts of the state until this evening.
Bureau of Meteorology meteorologist, Dean Narramore, said the cool change had reached the south west, and temperatures were in the mid 20s.
However ahead of that change it was hot and cloudy and temperatures had soared into the mid to high 30s and peaking in the 40s in northern and eastern parts.
The cool change would move into southern Victoria during the afternoon and evening and cross northern Victoria in the overnight hours, Mr Narramore said.
He said the change would drop temperatures 10 to 15 degrees.
The cool change would be followed by a band of rain and thunderstorms that would develop over South Australia today and then move across Victoria overnight and early morning hours tomorrow.
Widespread falls could be expected of five to 15 milimetres and up to 25mm possible from thunderstorms, particularly in the Mallee.
He said in Victoria temperatures should drop to the "high teens" in southern Victoria and the high 20s in northern Victoria.
"Near 20 on the coast and near 30 on the Murray," he said.
Mr Narramore said temperatures would warm up to high 20s and 30s in northern Victoria before another front moving through on Friday.
Total fire bans were issued in Victoria's Mallee, Wimmera, Northern Country, North Central, North East and East Gippsland districts, and across the Riverina district in NSW on Monday.
Hot to very hot, with fresh and at times gusty north to northwesterly winds over northern parts of Victoria.
