Heat warnings continue for much of Alberta with severe thunderstorms possible late Thursday

Thunderstorm risk possible for Calgary. Gina Martin has a look at the five-day forecast from the Sky Watch Weather Centre.

A dominant ridge of high pressure will push Thursday’s daytime highs to around 30 C across most of Alberta, prompting wide-spread heat warnings from Environment and Climate Change Canada.

Heat warnings are issued for most of Alberta (outside of the southernmost regions) when daily highs reach at least 29 C along with daily lows of at least 14 C for at least two consecutive days.

The threshold for the rest of the province require highs of at least 32 C plus lows of at least 16 C for at least two consecutive days.

Severe thunderstorm watches were issued for portions of the B.C. interior due to the likelihood of damaging storms developing, with some air quality advisories issued for portions of Alberta, Saskatchewan and Manitoba due to wildfires.

A brief period of instability is expected late on Thursday – associated with a frontal system originating in The Northwest Territories – may produce some intense thunderstorms from Great Bear Lake, N.W.T., extending south through most of Alberta and east to central Saskatchewan.

The greatest threats include strong winds, hail, heavy rain and potential rotation.

If these storms form, they will move quickly but that wind could rapidly impact fire behavior.

The recent unusually hot and dry weather has amplified the fire danger risk across the west.

As of 6 a.m. Thursday, most of Western Canada was sitting under an extreme rating for the fire danger relative index, an assessment of how easily a wildfire could start, how difficult it would be to control a wildfire as well as the potential damage that wildfire could cause.

That ridge of high pressure will reset after Thursday and keep temperatures in Alberta well-above seasonal for Friday and Saturday before another frontal system moves in from the north and finally dislodges this upper pattern that has been in place since the weekend.

On Sunday, the daytime high is expected to be around 13 degrees cooler than Saturday’s with light rain and possibly some thunderstorms.

The average range of temperatures this time of year is 18 C and 5 C.