CALGARY -- Without injecting opinion into the forecast, I’m sure it might be nice to have a few days where we settle, and stay settled. How fine a thing to see that change develop for Friday and Saturday?

But first…

A new low pressure zone is deepening (strengthening) over the course of today and tomorrow, with a moderate drop in pressure over a 24-hour period. This will push in another base of thundershower activity that could produce tennis ball sized hail and may be capable of producing a tornado.

Environment Canada, thunderstorm outlook

Environment Canada's thunderstorm outlook for July 7, 2020

Storm spotters and the general public in Alberta should keep their eyes open for potential tornadic development, which in some spots, on some models, lists like this:

Medicine Hat, cape, helicity, tornado

What are we looking at here? Medicine Hat's low-end CAPE (other communities well to the north today call for 2000 +, which is a significant difference, and a high-end helicity (the force of air rotating in a helix, which is a combination of the wind turning and vertical rate of flow).

This is to say: conditions will have to be perfect. Quite a few of the standing forecast models project high helicity - the element above that suggests violent tornadoes are possible with the caveat of storm development – the model (HRDPS) that says this also projects low helicity when CAPE is high, and vice versa. That is to say there may be plenty of gas in the tank but nothing to start the car in a few areas.

There is also a chance that, for the southeastern zone I’ve noted above, storms will remain dormant in their full capacity until crossing the boundary into Saskatchewan.

We saw it earlier this week, too, and this is the challenge of projecting and calling for tornadic activity. The last thing any weather forecaster wants to do is misinform. Therein, potential is stated. We’ll be watchful this afternoon.

Back to Calgary…

Tomorrow, this low will likely send some moisture along but could be pushing into some 60-70 km/h wind gusts for us, then opens for some thundershower potential as its last local hurrah before migrating east.

Here’s the forecast:


  • Partly cloudy, chance of afternoon thundershowers
  • Daytime high: 21°
  • Evening: partly cloudy, low 11°


  • Mainly cloudy, scattered showers, windy
  • Daytime high: 16°
  • Evening: clearing, low 9°


  • Partly cloudy, slight chance of pm thunderstorms
  • Daytime high: 21°
  • Evening: mainly clear, low 12°


  • Mainly sunny
  • Daytime high: 24°
  • Evening: clear, low 12°


  • Mainly sunny
  • Daytime high: 25°
  • Evening: clear, low 10°

Today’s photo is from Alan, enjoying a Spruce Point sunset.

Photo of the Day, July 7, Spruce Point

You can submit your weather photos here!