Metro Vancouver forecast calls for sun, clouds and showers

Vancouver is expected to have a mild start to the week before a weak system brings cooler temperatures, cloud and showers, according to Environment Canada meteorologist Morgen Shull.

Tuesday is expected to reach about 21 C, with a low near 13 C, normal for this time of year. Wednesday should see similar temperatures for most of the day.

A weak cold front is expected to move across the province from Wednesday night into Thursday. It could bring showers and lower daytime highs to 17 C or 18 C from Thursday through Sunday.

Shull said instability behind the front and a weak trough, an elongated region of low pressure, will make the forecast from Friday uncertain. The most likely outlook is for a chance of showers Friday into Saturday, followed by clearing Sunday, but that could change.

The system could develop over Vancouver, bringing heavier showers and more cloud, or move offshore, leaving scattered lighter showers and some sunny breaks. Its arrival time is also uncertain. If it develops over the city, showers could begin Friday morning.

Either way, the weather is not expected to be dramatic, with highs near 18 C and lows around 11 C. A drying trend is expected in Vancouver by Sunday, Sept. 13, with some sun and a possible high of 20 C.