Showers are moving across the Toronto area this morning. Here's a look at the radar at 8:30 am:
In the water vapor image, you can see an upper level low pressure system spinning counter-clockwise, centered over the western tip of Lake Superior. That is what will bring showers to CTMP on Saturday. Once the cold front moves through tonight, there will be a break in the rain until the upper level low moves overhead, which is expected to occur tomorrow. There could be showers any time of the day, but I expect that most of it will come in the afternoon when a little heating will help add some instability. The amount of rain on Saturday should be less than today, maybe around a tenth of an inch.
Sunday still looks nice as the upper low tracks east and drier air builds in behind it. Expect partly cloudy skies and highs in the upper 70s.
Here the updated forecast graphic: