Thursday will be slightly cooler across southern Ontario, with a mix of sun and cloud expected in the London area. CTV meteorologist Julie Atchison says London is expected to reach a high of 18 C, with gusty west winds developing through the afternoon. Winds will reach 30 km/h, with gusts up to 50 km/h. Scattered showers are possible north of the city, particularly around Bruce County and areas affected by moisture coming off Lake Huron and Georgian Bay. London is expected to see a fair amount of sunshine through the day. Friday will be mostly beautiful, with a high of 17 C, while Saturday will bring a mix of sun and cloud. The holiday weekend could see some changes as moisture from a tropical storm in the Gulf potentially moves into southern Ontario. Atchison says the exact impact remains unclear, but a 40 per cent chance of showers has been introduced for Sunday, with increased cloud cover expected Monday. Despite the chance of showers, the weekend is expected to remain warm enough for outdoor activities.