This summer in the Moose Jaw area has been unpredictable in terms of weather, from thunderstorms to heavy rainfall, tornado warnings, brief heat waves, and more.
As it has for many years in the area, weather patterns this summer have been very scattered, where your residence could get heavy rainfall, and your neighbour down the road doesn’t get a single drop. Or another example would be a storm literally splitting around your area and completely missing. Saskatchewan's weather is unique, to say the least, but why?
Natalie Hasell, an Environment Canada Meteorologist explains what makes Saskatchewan's weather patterns so unique.
“This is especially true in the summer, due to the character convective weather talking about showers, talking about thunderstorms. This time of the year most of the rain we see is convective, therefore it’s not flat and widespread and everyone gets a lot. It’s kind of more scattered and scarce situation.”
Convective weather is described by the transportation of heat and moisture by the movement of a fluid.
In meteorology, the term is used specifically to describe the vertical transport of heat and moisture in the atmosphere, especially by updrafts and downdrafts in an unstable atmosphere.
Hasell adds when it comes to thunderstorms – though they may look big and fierce – they are actually quite small in size.
“If you have a storm go over Moose Jaw it’s quite possible that part of the city doesn’t get any rain, or gets much less than the other part of the city that could get quite a bit more. Not all of the showers that development is going to be really big storms.”
When it comes to rainfall amounts, Hasell explains that there is a caveat. In Moose Jaw, the weather station is at 15 Wing, which records the precipitation for the city. If a storm doesn’t hit 15 Wing but hits the inner city, then unfortunately Environment Canada will have to report zero rain in their daily update.
“Our official data might not be very representative of what people actually experienced.”
Another factor when looking at the Saskatchewan weather patterns is the amount of moisture in the soil.
“That precipitation might still be available in the soil or in the plants through evapotranspiration to feed the storms, so it could become a local source of moisture, but if you have an area not too far away that didn’t get any rain from the previous system, well this next system may not be able to feed on anything in that area, so those storms tend to be smaller.”
Evapotranspiration is the name given to the total water loss to the atmosphere from a land surface, usually expressed in units of depth; it includes the water vapour evaporating from the soil surface and from the liquid water on plant surfaces together with that transpired from within plant surfaces.
Early on in spring southeastern parts of the province were hit with a mass amount of rain. In May, Estevan received 133.1 millimetres of rain, which ranked sixth in over 100 years of Environment Canada data. Yorkton, recorded 137.9 mm, which was 269 per cent more than is normal seen in May at 51.3 mm.
Places in the southwest and south central such as Regina, Moose Jaw, and Swift Current received some moisture, but not enough.
Fast forward to August, Hasell has noticed rain patterns are switching to the southwest with hopes of more rain, due to recent rainfall adding moisture into the ground to feed storm systems – producing more precipitation.