A series of severe thunderstorm watches have ended for Toronto and the Greater Toronto Area as the region copes with its first official heat wave of the year.

Because of the uncertainty of conditions, the watches were issued for wide areas of southern and eastern Ontario.

Tornado warnings briefly issued

Environment Canada issued and then quickly cancelled a flurry of tornado warnings for a number of areas in southern Ontario as thunderstorms threatened a large swath of the province Thursday.

Tornado warnings were issued at 2:39 p.m. and then quickly cancelled by Environment Canada for parts of the GTA, including Vaughan, Richmond Hill, Markham, Mississauga, Brampton, Newmarket, Georgina and northern York Region.

Tornado warnings were also issued earlier for Innisfil, New Tecumseth, Angus, Caledon, Orangeville, Grand Valley, Shelburne, Mansfield and Dufferin County.

By about 3:10 p.m., all warnings had ended.

There were two reports of active tornadoes or funnel clouds around 2:30 p.m., Peter Kimbell, a warning preparedness meteorologist at Environment Canada, told CTV News. He said one had been spotted near Orangeville while the other had been spotted east of Shelburne.

No tornadoes are so far confirmed to have touched down.

Heat wave official

The warnings come as an official heat wave was declared for Toronto when the temperature hit 32 C Thursday.

Environment Canada defines a heat wave as at least three consecutive days when the maximum temperature is 32 C or higher.

A weather station at Pearson International Airport matched or broke that mark Tuesday (32.7 C) and Wednesday (34 C), and Thursday's high clinched the region's first official heat wave of 2013.

Official heat wave or not, people have been finding ways to escape scorching temperatures that are now in their fourth day.

An extreme heat alert and a humidex advisory remain in effect, with humidex values expected to be in the low-40s.

The hot and humid weather will continue Friday with a high of about 34 C, but the temperature will return to seasonal territory on the weekend.

Environment Canada said cooler and drier air is expected to move in late Friday, bringing a break from the extreme heat and humidity.

After a high of 27 C Saturday, Environment Canada expects a high of 23 C Sunday and highs of 25 C Monday and Tuesday.

Normal temperatures for this time of year are highs of 27 C and lows of 17 C.

Meanwhile, the following cooling centres are open to the public until the extreme heat alert is called off:

  • Centennial Recreation Centre, 1967 Ellesmere Rd. (11 a.m. to 7 p.m.)
  • Driftwood Community Centre, 4401 Jane St. (11 a.m. to 7 p.m.)
  • East York Civic Centre, 850 Coxwell Ave. (11 a.m. to 7 p.m.)
  • Etobicoke Civic Centre, 399 The West Mall (11 a.m. to 7 p.m.)
  • McGregor Community Centre, 2231 Lawrence Ave. E. (11 a.m. to 7 p.m.)
  • Metro Hall, 55 John St. (open 24 hours)
  • North York Civic Centre, 5100 Yonge St. (11 a.m. to 7 p.m.)

People can also cool off in shopping centres and public libraries.

Weather permitting, these pools are open until 11:45 p.m.

  • Alex Duff Memorial Outdoor Pool, 779 Crawford Ave.
  • Alexandra Park Outdoor Pool, 275 Bathurst St.
  • Cummer Park Indoor Pool, 6000 Leslie St.
  • Giovanni Caboto Outdoor Pool, 1369 St. Clair Ave. W.
  • McGregor Park Outdoor Pool, 2231 Lawrence Ave. E.
  • Monarch Park Outdoor Pool, 115 Felstead Ave.
  • Smithfield Outdoor Pool, 175 Mount Olive Dr.
  • Sunnyside-Gus Ryder Outdoor Pool, 1755 Lake Shore Blvd. W.

Toronto Public Health says people should follow these tips to stay cool:

  • Drink lots of cool water
  • If you don’t have air-conditioning at home, go to a shopping mall, library or community centre
  • Wear loose, light-coloured and breathable clothing and when outdoors wear a wide-brimmed hat
  • Avoid the sun and stay in the shade or use an umbrella
  • Plan outdoor activities during the cooler parts of the day
  • Take cool showers or baths, or use cool wet towels to cool down
  • At home, keep blinds or drapes closed to block out the sun
  • Make meals that don’t require an oven
  • Put a fan next to a window to bring cooler air in from outside

Toronto Public Health offers these tips to keep pets safe and cool:

  • Provide plenty of fresh water
  • Limit your pet’s exposure to the sun to avoid sunburn
  • Use air-conditioning or a fan to keep your home cool
  • Provide shade if your pet ventures outdoors
  • Never leave a pet unattended in hot weather on balconies or in unsheltered backyards
  • Overeating during hot weather can lead to overheating, so let your pets eat less
  • Take dogs for walks during the cooler parts of the day
  • Signs of heat stroke include rapid panting, lots of drooling, hot skin, twitching muscles, vomiting and a dazed look

Toronto's 11 public beaches currently have a "safe to swim" status, the city says.

@ChrisKitching and @Josh_F are on Twitter. For instant breaking news, follow @CP24 on Twitter.