The warning has been issued for central Melbourne and regions including Gippsland and south-western and north-eastern Victoria on Monday and Tuesday as the city basks in sunshine after what was the coldest start to November in more than two decades. 

Grass pollen levels were said to be "Extreme" on Monday.

A moderate risk forecast means that one of the elements necessary for a thunderstorm asthma epidemic may be present.

Those at increased risk should avoid exposure to any storms that may emerge, especially the wind gusts that precede them and have a reliever available.

EARLIER: It certainly feels like summer has come early for Ballarat, but with summer comes the chance of thunderstorms.

And the thunderstorms could come as early as this evening.

The Bureau of Meteorology forecast says there is a 50% chance of showers in the afternoon and early evening, with a thunderstorm also possible.

The forecast comes hot on the heels of an early burst of summer in the city.

The mercury has been gradually climbing from a top of 24.5 degrees on Thursday and is expected to reach 29 degrees and even crack 30 degrees tomorrow.

We could also see a healthy downpour of rain as the cool change comes late on Wednesday.

However, the temperature will drop later in the week as Thursday and Friday maximum temperatures both fall back into the mid-teens.