Warm & Wet Weekend Across Southern Ontario With Temperatures Into the 20s and Up to 20–40mm of Rain on Sunday
/Valid: Saturday, September 12, 2020 - Sunday, September 13, 2020
It has been a fairly mild and in some cases, chilly start to fall across Southern Ontario with multiple nights of frost advisories in the more northern areas of the region. Thankfully we aren’t talking about the other f-word just yet and that appears to hold true for at least the next few weeks.
In fact, we’re looking at the exact opposite with much warmer temperatures expected this weekend with the thermometer reaching into the 20s on both days for some areas. For Sunday, the warm temperatures will also be accompanied by heavy rainfall beginning early in the morning and lasting throughout the day. Thunderstorms are also possible in some areas which will increase the potential rainfall totals with local amounts up to 40mm.
On Saturday we will see temperatures ranging from 20-25°C as daytime highs through regions south of Lake Simcoe and out into Eastern Ontario along the international border. Central Ontario and Northeastern Ontario will be slightly colder with daytime highs between 15-20°C.
Moving onto Sunday we will see even warmer temperatures than on Saturday with the 20-25°C zone including much of Southern Ontario. Only very northern parts of Central Ontario and Northeastern Ontario will see a daytime high of less than 20°C. A corridor extending from Extreme Southwestern Ontario and into the Golden Horseshoe could see temperatures reach into the mid to high 20s although this isn’t guaranteed and could very well stay between 20-25°C.
As mentioned, Sunday will also bring the potential for heavy rainfall throughout the day beginning just after midnight. The focus will be a zone to the east of Lake Huron and Georgian Bay where a particularly heavy band of rain could affect the region Sunday morning. This will clear up around noon, but another zone in Eastern Ontario including Kingston and Brockville could also see heavy rainfall during the early afternoon. Other areas will see scattered rain and showers throughout the day with the highest chance earlier in the day and clearing up by the evening.
Rainfall totals will generally range from 10-20mm by the end of the day. Although a few localized spots especially in the aforementioned regions could see between 20-40cm as shown in the orange on the map below.
As we start of a new week, we’ll see temperatures cool down slightly with daytime highs in the mid to high teens. It will only get colder the further we go into the week with the potential for frost returning in the higher elevations by Thursday and Friday. It looks like this may be one of the last real burst of heat left this season before we get deep into fall and yes, winter.
