Prairie Weather (Rural Roots Canada) – Get ready for a wet, and sometimes stormy week across the prairies.   In many areas, harvesting has begun, and those operations may be interrupted from time to time, as a series of showers and storms crosses the three provinces all week long.

On the positive side, the rain and cool weather may further limit the damage done to crops over the summer by the hot, dry weather.   On the negative side, many of the storms set to cross the prairies this week could produce hail, adding to an already high damage total this year.     Indeed, according to the Alberta Crop Report, hail damage has been considerable in western Alberta, whereas most of the crop damage in the eastern half of the province has been due to hot, dry weather.    Heat and grasshoppers are the main causes of damage in parts of Saskatchewan, so the expected rain this week will be most welcome.  The topsoil is particularly dry south and west of Saskatoon:

Wasting no time, the parade of showers and storms begins Monday.  In the afternoon, storms will fire up along the foothills and move northeast.  There is a real risk of severe storms – supercells that could produce large hail, among other hazards associated with severe weather.  (Area “A” on the map below)   Here is Environment Canada’s Thunderstorm Outlook for Monday,  August 19:

Note the mention of a tornado threat for area “A”.  The threat is low, but watches and warnings should be carefully monitored in this area Monday afternoon.    You can find the watches and warnings here: https://weather.gc.ca/

In the area labelled “C” in southern Saskatchewan, hot and humid air comes in from the south, and the atmosphere is already unstable due to an upper trough of low pressure.   The hot, humid conditions will intensify the instability.    Severe weather may hold off into the evening or later into Monday night, when the northern edge of a major storm forecast for northern Montana creeps into southern Saskatchewan.

RELATED: Hail Report: Alberta Crops Most Affected By Recent Storms

As mentioned, more showers and storms are expected for the rest of the week, along with hot, humid conditions along the US border.

Monday:

The previously mentioned Monday storms could fire up early in the morning around Waterton/Pincher Creek, and north of Edmonton.  Those storms will move northeast through the day.    In the daytime, a few showers can be expected in Saskatchewan and Manitoba. Going into the evening, though, storms will develop in central and northern Saskatchewan, setting the table for a very active, and potentially dangerous Tuesday.

Tuesday:

The potential for severe weather is quite pronounced on Tuesday in Saskatchewan.   Below is a map of CAPE, Convective Available Potential Energy.   The map is valid mid-afternoon.    Thunderstorms are possible in any of the shaded areas on the map, but in Saskatchewan, in the areas shaded orange, red, and purple, there is a high chance of severe thunderstorms, with strong wind and large hail, and a potential for tornadoes:

Again, watches and warnings will need to be closely monitored.   Behind the storm, Alberta will be relatively quiet, though there is the potential for non-severe thunderstorms.   Manitoba will also be relatively quiet, but the Saskatchewan storms are on their way.

Wednesday:

Early Wednesday morning, the severe weather in Saskatchewan crosses into Manitoba, with strong storms possible in the Dauphin/Roblin area.  Thunderstorms will extend north of there along the Saskatchewan/Manitoba boundary.   Those storms weaken rapidly as they cross into Manitoba’s drier air, and by noon, the severe weather threat should be over.    However, rain and non-severe storms are possible for the rest of the day in central and northern Alberta, and in central Manitoba between Lake Winnipeg and the Ontario boundary.   Rainy weather will then persist into the overnight hours all across the prairies.

Thursday:

Thursday’s a rainy day in Manitoba, with a few scattered showers and thunderstorms hanging back in Saskatchewan and Alberta.  A surface ridge of high pressure will build in Alberta, and spread eastward, pushing the Manitoba rain to the north and east, and clearing out the sky across the southern prairies particularly Thursday night and Friday morning.

Friday:

Friday’s a “calm before the storm” kind of day, with no active weather expected across the southern prairies.   It may be a good day for those harvesting to get back in the fields.  Work fast…more stormy weather could be on the way for the weekend, depending on where you are.

Saturday:

The atmosphere becomes unstable again, and this could be an interesting day.   As of the writing of this forecast, it’s way too early to be specific, but it looks like a Low pressure system will develop at the surface in southeastern Alberta.    This could kick off some isolated thunderstorms from the Alberta foothills to Brandon, and as far north as Prince Albert.   Another Low, in the Northwest Territories, will destabilize the atmosphere in northern Alberta, where, again, showers and thundershowers will be possible.   Most of these are hit-and-miss storms, some of which may be heavy or severe.    At this point, an inverted trough of Low pressure looks to develop in southern Saskatchewan, and if it does, it could generate some severe weather northwest of Saskatoon.

Sunday:

A low will form along that inverted trough and travel to Hudson Bay on Sunday.   Behind it, high pressure will build across the prairies, and sunny weather returns.

La Nina Update

We are now firmly in the neutral cycle, the time period between El Nino and La Nina.   La Nina conditions are expected to emerge September to November, and persist through the beginning of the New Year.   With a full strength La Nina possible January – March, western Canada could be in for a cold, snowy winter.    How come?

Check out the coloured arrows.  The purple arrow is the Polar Jetstream.   In a La Nina, the polar jet plunges into or south of the prairies, drawing cold, arctic air into western Canada.   The red arrow is the Pacific Jetstream.    It brings Pacific storms on shore to the coast of Washington.   Those storms then travel eastward through Idaho, Montana, and North Dakota.   Being just north of the storm track, the storms that do pass by will push their moisture to the north into the Canadian Prairies, and we get snow.    When the storms are over Montana, the snow will be pushed by an easterly wind up against the foothills and mountains, creating an upslope effect, increasing the snowfall.     Bottom line:  Prepare for cold weather, heavy snow, and great skiing this winter.

Event Forecasts:

 Rural Roots Fair 2024, August 24, Beaumont, AB

August 24:  Rain, high 16

Okotoks Pro Rodeo, August 23-25, Millarville, AB

August 23:  Sunny, chance of evening thunderstorms, high 27

August 24:  Mostly cloudy, evening thunderstorms, high 17

August 25:  Becoming mainly sunny, high 18

Agra Fair, August 24-25, Spruce Grove, AB

August 24, Rain, high 16

August 25, Sunny, high 20

Lawn Tractor Races, August 24, Cherry Grove, AB

August 24, Rain, high 19

Morden Corn and Apple Festival, August 23-25, Morden, MB

August 23,  Mainly sunny, high 27

August 24, Mainly cloudy, high 28

August 25,  Mainly sunny, evening thundershowers with gusty wind, high 33

AG Days, August 23-25, Russell, MB

August 23, Sunny, high 25

August 24, Partly cloudy, slight chance of showers, high 25

August 25,  Mainly sunny with midday clouds, high 23

COMPARE TO LAST WEEK’S REPORT: Prairie Weather This Week – August 12