Hazardous heat to mark southern Ontario’s hottest week this summer
After a stormy Saturday that saw slow-moving cells dump copious amounts of rainfall in parts of southern Ontario, the potential will surface again Sunday, albeit somewhat diminished, thanks to a warm front. The heat and humidity continue to escalate, and in fact, will continue to worsen this week. The next stretch of days ahead could feature the hottest days of the summer so far, with multiple communities feeling close to, at or even above 40 for several days. A heat warning is already in place in southwestern Ontario. The severe storm risk will become more widespread Monday as a result of instability building. A closer look, below.
SUNDAY: TEMPERATURES CONTINUE THEIR CLIMB, STORM THREAT DIMINISHES
A warm front moving through southern Ontario Sunday sets up a thunderstorm risk in the region, but most areas will see just a potential for non-severe storms to develop in the afternoon.
A small area near southern Georgian Bay, and central and northern Lake Huron shores could see storms reach severe criteria. The main threats will be heavy downpours, gusty winds, and small hail with the potent storms.
Meanwhile, the heat and muggy conditions will continue. A heat warning is already in place for the extreme southwest. Parts of the extreme southwest could exceed 30°C, but the rest of the region will be close behind with daytime highs approaching the 30-degree mark.
Humidity will also linger so most places will be feeling well into the 30s, nearly 40 in the southwest and far eastern Ontario.
MONDAY AND BEYOND: MORE STORM CHANCE, COULD BE HOTTEST WEEK OF THE SUMMER
All the humidity that has been climbing in recent days will gradually boost the region’s PWAT (precipitable water in the atmosphere), resulting in any rain that does occur will be heavier and longer-lived.
Monday and Tuesday look particularly likely to be a rainy one for many people, particularly from the afternoon into the evening, thanks to instability arising from the heat and humidity.
The threat for severe storms returns to parts of southern Ontario Monday, with the potential focused on an area stretching from southern Lake Huron to cottage country and eastern areas, spilling over into western Quebec, as well. It will remain north of the GTA.
Meanwhile, the heat and humidity will continue to build to uncomfortable and even dangerous levels through the week.
In fact, this week should be the hottest week of the summer across southern Ontario and Quebec. Temperatures will remain locked into the upper 20s and lower 30s, with a humidex in the high-30s and low-40s for much of the week. It will be very humid.
The hottest day so far this year for Toronto happened on June 6, when the city recorded a daytime high of 33.8°C.
The culprit will be a ridge of high-pressure parked by the southeastern U.S. In atmospheric terms, it will have the effect of ushering warmer southwesterly winds up into southern Ontario for several days.
TIPS FOR KEEPING COOL IN THE HEAT
When planning for next week, people should expect to have to limit outdoor activities and make active preparations to keep cool.
Safety Tips Extreme Heat
During a heat event, Environment and Climate Change Canada (ECCC) says the risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.
Watch for the effects of heat illness: swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions
Check on older family, friends and neighbours. Make sure they are cool and drinking water
Never leave people or pets inside a parked vehicle
Also consider these tips to staying cool including eating spicy foods, taking vitamins, stay in the shade, consider hot over cold drinks, and avoid dark clothing.
WATCH BELOW: IS IT DANGEROUS TO DRINK ICE COLD WATER ON A HOT DAY? WE ASKED AN EXPERT
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Check back as we continue to monitor the long-range forecast in southern Ontario.