Melbourne is expected to be lashed by damaging winds on Wednesday as severe weather makes its way across the state.

A warm to hot northwesterly airstream is forecast to bring wind gusts of up to 100km an hour with peaks expected about 10am, 4pm and 8pm.

The Country Fire Authority has declared Wednesday a day of total fire ban across all of Victoria except East Gippsland

Bureau of Meteorology senior forecaster Scott Williams said the weather system was unusually intense.