Calgary faces possible storms after Stampede Sneak-A-Peek

Today will feature a risk of significant storms across parts of our province. A spin-up will begin this afternoon and roll across the province into Central Alberta by the evening. Yesterday, I reported hail sizes could be slightly larger than a billiard ball (six centimetres) – now, the outlook shows areas where tennis ball sized hail is a possibility. Wind will also be a significant factor, with some areas receiving gusts in the triple digits. As these storms mature further east, tornado possibility remains.

I looked at events similar to the conditions Calgary's forecast is in line for (the significant hail parameter of the SARS Sounding Analogs) – in 209 loosely-matched events, just under 50 per cent resulted in hail sizes greater than pennies. Get the car covered.

If you’re planning to head down to the Stampede grounds for Sneak-A-Peek, be sure to check the forecast; with the kick-off at 5 p.m., it may be prudent to wait a couple of hours.

Start time for this storm remains variable, as activity forming from the foothills often does. Most models agree at this point: 4 p.m. to 8 p.m. is the most likely window. Some models show a wind-up closer to 3 p.m., and others still offer a small chance the storm "splits" around us.

I've briefly touched upon potential for weather to take a turn now as we delve deeper into Stampede; that’s starting to show on forecast models, with a slight chance for showers or thundershowers creeping into Friday evening's forecast. Saturday and Sunday both show faint potential as well, but are otherwise warm and sunny.

In brighter news for those missing the heat – the seven-day trend showcases our first potential 30 C day of the year – heat-mongers, it's on the way.

YOUR FIVE-DAY CALGARY FORECAST:

Thursday (Sneak-A-Peak)

• Partly cloudy, risk of severe p.m. thundershowers
• Daytime high: 24 C
• Evening: showers, storm risk, low 12 C

Friday (Parade Day)

• Building cloud, slight afternoon shower, storm risk
• Daytime high: 26 C
• Evening: showers, storm risk, clearing overnight, low 12 C

Saturday

• Sunny
• Daytime high: 24 C
• Evening: mainly clear, low 12 C

Sunday

• Mainly sunny
• Daytime high: 22 C
• Evening: mainly clear, low 11 C

Monday

• Sunny
• Daytime high: 27 C
• Evening:  clear, low 12 C

Yesterday, significant storm potential existed near Medicine Hat – that resulted in this magnificent cloud formation seen here – undulatus asperitas. They're dark and stormy-looking, and usually fade without a storm occurring. Andrea says she took this photo while "getting her butt kicked on the front nine" in Redcliff, Alta.

Viewer Andrea's photo of storm clouds near Redcliff, Alta.

With stormy weather on the horizon, we'd love to see your photos, but only if it's safe to do so.

Submit your weather photos here to see them featured in our article, and perhaps even as the pic of the day during our News at Six! You can also share on Twitter, or to our Instagram at @CTVCalgaryWeather.