As the season turns from spring to summer, Melbourne is set to endure a burst of hot, humid and thundery weather. A slow-moving low pressure trough is the cause of the unsettled conditions, directing hot air sourced from the nation's interior over Victoria's capital on Sunday and Monday. This trough has also tapped into the increased buildup of moisture across the continent over the past fortnight, causing a more humid heat while also leading to the risk of thunderstorms. Today will be the hotter of the two days, with the city on track to reach 34 degrees, although it won't be significantly humid. However, those out and about might get caught out as showers and thunderstorms develop during the afternoon, most likely in eastern suburbs. Monday will be a little cooler than Sunday but more humid, reaching 30 degrees before a gusty southwesterly change moves through during the late morning or early afternoon. It will be a good idea to get out early in the day as thunderstorms redevelop from the late morning, which will again favour eastern suburbs. A high pressure ridge will clear thunderstorms by Tuesday leading to a mild and dry day, before the risk of thunderstorms returns from midweek near another trough.