Late summer-like weather at times this week; Mid-autumn weather for the weekend
Meteorologist, PhD
Monday, September 29, 2014, 2:47 PM - Monday afternoon across the GTA will be much like this past weekend with sunshine and temperatures more typical of August.
However, an interruption from the pleasant weather is on the way for Tuesday with a more significant pattern change as we head into next weekend.
Showers are likely on Tuesday, and a thunderstorm is also possible early in the day with temperatures closer to seasonal for the final day of September. The average high for this time of year at Toronto’s Pearson airport is 18°C.
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Sunshine and mild temperatures will return for Wednesday and Thursday. High temperatures in the GTA will not be as warm as what we saw last weekend due to a southeast wind off of Lake Ontario, but highs in the lower 20s are still a few degrees above seasonal.
A strong cold front will cross Southern Ontario Friday afternoon and evening, bringing windy weather throughout the day as well as a period of rain. The timing of the rain is still somewhat uncertain, but at this point it looks like the rain will develop during the afternoon and continue through the evening.
The weather this weekend will be quite a contrast to last weekend as our high temperatures in the lower teens will be more typical of late October. Isolated showers are possible in the GTA on Saturday, but most of the day will be rain-free. However, the showers will be more numerous and widespread closer to Lake Huron and Georgian Bay as lake effect shower are likely.
Sunday continues to be rather chilly for early October, but it will be a drier day with more sunshine mixing in with the clouds.
Temperatures will recover closer to seasonal on Monday, but another round of chilly weather is expected for Tuesday and Wednesday.
Looking even further ahead towards the Thanksgiving long weekend, several models indicate that the above pattern will persist through at least the end of the week. However, there are signs that we will actually see a faster transition out of that pattern than what those models indicate. This pattern change would shift the coldest weather back to the Prairies and allow milder weather to return to parts of eastern Canada, and potentially southern Ontario as we head into the long weekend.
