Tuesday, September 7th 2021, 4:56 pm - The long weekend wasn't storm free, and Tuesday features a setup that may include rotating storms later in the day.
Editor's Note: This article is no longer being updated. CLICK HERE for the latest on Tuesday's severe thunderstorm threat in Ontario.
The early morning hours of Labour Day featured rumbles of thunder, heavy local downpours and even a brief tornado warning. On Tuesday, most of the day will be storm-free, but that storm risk builds back in around the dinner hour, most severe along the shores of Lake Huron. Forecasters are keeping an eye on that area in particular, given the possibility of rotating storms. What we know so far, below.
TUESDAY: SEVERE THREAT IN SOUTH INCLUDES TORNADO CHANCE, BUT TIMING IS KEY
Strong storms rolled through much of southern Ontario in the early morning hours, at-times severe, with at least one potential tornado under investigation in the Port Albert area.
Looking ahead, Tuesday holds a fair bit of severe storm risk as well, firing up around the dinner hour. Strengthening mid-level winds and improving shear along the cold front will drastically increase the severe storm potential across Michigan and southwestern Ontario.
With the shorter days upon us, the timing of the front will be crucial to the storm severity on this side of the border. The Lake Huron shores will have the best chance for severe storms Tuesday evening with embedded rotation and larger-sized hail possible. Because of the chance of rotating storms, there is the potential for a tornado or two in this area in the southwest.
In addition to the hail and tornado risk, the severe storms may also bring strong wind gusts and heavy downpours.
The GTA will see the arrival of the line of storms well after sunset, but isolated strong to severe storms will be possible from the GTA to central Ontario. After midnight, the line of storms will weaken as it moves through eastern sections.
There will also be a risk for non-severe thunderstorms in northwestern and northeastern sections Tuesday.
Tuesday will see slightly warmer daytime highs in the south, reaching the mid-20s in most areas, even approaching the 3-degree mark in southwestern areas. The humidity will also make a return on southern sections, with feels-like values reaching into the low to mid-30s.
LOOK AHEAD: TEMPERATURES COOL OFF, POTENTIAL FOR PERIOD OF MID-SEPTEMBER WARMTH
Beyond Tuesday, a few days of cooler temperatures behind this system -- dropping to near seasonal or a few degrees below seasonal.
Forecasters are watching the potential for a period of above seasonal temperatures for mid-September. However, keep in mind that seasonal temperatures are steadily falling now, so it will not be nearly as warm as what we saw during August.
Stay tuned for the latest forecast across Ontario.