Thunderstorms that rocked many of Vancouver Island's population centres over the weekend could return for an encore performance this afternoon.

Environment Canada is predicting the risk of a thunderstorm along the Island's southeast coast, from Victoria to Campbell River.

The forecast comes after a hail storm hit parts of the Cowichan Valley on Sunday on the tail end of a weather system that also brought lightning and heavy rain to the region.

Environment Canada鈥檚 Armel Castellan said it鈥檚 very rare for south east Vancouver Island to receive such weather at this time of year, and said it鈥檚 the result of low-pressure system that has been stationary off the coast of Oregon for the past several days.

He said the storm system that brought the thunderstorms and hail came in two pulses; one on Saturday night and the other on Sunday.

Castellan said the wet and cooler than usual weather is forecast to continue into the latter part of this week, with more than 20 millimetres of rain expected Wednesday through Thursday.

鈥淭he low-pressure system off Oregon will weaken, but will be replaced by another low-pressure system that鈥檚 coming down from Alaska that will bring a fair amount of rain to the Cowichan Valley and the island鈥檚 south coast,鈥� he said. 鈥淚t will also bring cooler temperature with it that will be about four to five degrees Celsius lower than normal for this time of year.鈥�

However, Castellan said more summer-like weather is forecast to return later in the week and the weekend should see a mix of sun and clouds and temperatures in the mid to low 20s.

鈥淚t won鈥檛 compare to those hot days that we had in July, but the days are starting to get shorter now and we鈥檒l be heading into the fall season with cooler temperatures expected as the summer winds down.鈥�