Friday will be a good day to get outdoors in southern Ontario, should you have any inclination to do so. The pleasant conditions won't last long into the weekend, however, thanks to an impending cold front set to track through from the northwest. Depending on its arrival will determine when the anticipated rain and thunderstorms set off. As of now, it appears the storms will hit the southern Lake Huron shores into southwestern Ontario first, forecast to develop Saturday morning. The showers and thunderstorms will arrive later in the day in the GTA, with the better chance of storms expected to occur in the evening. Because of the ample moisture available, any storm that does fire up is expected to produce torrential rainfall. Sunday may also yield more storms for parts of the region as the instability lingers in behind the system. More on Saturday’s storm threat and what to expect next week, below.
FRIDAY: GENERALLY NICE, THOUGH A PASSING SHOWER OR STORM POSSIBLE IN SOUTHWEST
While the northwestern parts of Ontario could be in for a stormy Friday, the south will enjoy a pleasant day before it will get its turn at seeing the same thunderstorm risk Saturday.
However, the southwest could see a passing shower or thunderstorm in the evening, thanks to a warm front scraping by.
Mainly comfortable conditions are anticipated, with daytime temperatures around seasonal, but will feel slightly warmer with the humidity.
SATURDAY: A THREAT FOR STORMS, BUT TIMING IS EVERYTHING
Saturday won't be as transparent as Friday will be. A cold front situated in northern Ontario will continue pushing through the Great Lakes region Saturday. An abundance of upper-level energy will come arrive ahead of the front, bringing a storm threat, but there is still lingering uncertainty around exact timing.
There’s some disagreement among the weather models on the specific timing of the front and the ensuing rainfall. At this point, it looks like showers and thunderstorms will develop along the Lake Huron shores, Bruce Peninsula, down through southwestern Ontario through Saturday morning. Extreme southwesterm areas are likely to see storms fire up through the morning. Some of the storms in these regions may reach severe limits, with heavy rainfall and strong wind gusts the main hazards.
The GTA is likely to see cloudy skies in morning, with showers developing in the afternoon, but the better risk of heavier rain with thunderstorms is anticipated to occur in the evening Saturday.
Very high moisture values are available, not at the surface, but right through to the mid- and upper-levels of the atmosphere, which means there is a high probability for storms to bring torrential rains from tapping into the moisture.
Exact amounts are not set in stone, but higher totals are expected in thunderstorms.
It’s a good idea to check back for the latest updates on the precise timing of the rain and storms.
Once the front passes, it won't be strong enough to wipe out the instability completely, leaving behind the risk for showers or thunderstorms Sunday along the Lake Erie shores and Niagara region as the energy remains.
NEXT WEEK: WARM AND FAIR WITH RAIN CHANCES RETURNING BY MIDWEEK
Near seasonal temperatures are expected for the second half of next week.
The last week of July would typically see a seasonal high of about 27°C in Toronto. Highs next week should climb into the upper 20s every day, with humidex values well into the 30s during the afternoon hours.
After this weekend, the next chance for widespread showers and storms will arrive with the next front around the middle of next week.
A changeable pattern is expected to dominate through early August, so we do not expect any prolonged periods of hot weather during the first half of August.
Stay with The Weather Network for the latest forecast across Ontario.