Prairie Weather (Rural Roots Canada) – With the dominance of hot, dry weather through July, the prairies, especially the western prairies, are once again in need of moisture.   And, while cooler weather is on the way for the end of the week, there is little chance for precipitation in the agricultural south.    The outlook is more promising for farmers and ranchers in northwestern Alberta, and rain is anticipated this week for the boreal forest in the northern prairies.

Through Thursday, high pressure will continue to dominate, meaning sunshine, hot weather, and the ever-present threat of isolated afternoon thunderstorms, some severe, with hail.  Nowhere in the agricultural prairie lands do we see the potential for significant rainfall this week, even after temperatures drop.

It’s all about the blue blob on the left side of this image:

That blue blob is an area of low pressure about 18,000 feet aloft.   Over Alberta, the orange colour indicates a ridge of high pressure.   The map above  is valid midday Monday, and under the ridge,  it will be hot, sunny, and dry across the prairies.   Under the blue blob, there is cooler air.

The blue blob will move east into British Columbia by noon Thursday:

With the Low over southern British Columbia, very warm air will be drawn up from the southwest, producing more hot weather for the prairies, especially Saskatchewan, where temperatures could approach 40 degrees.

The chart below shows temperature forecasts from various computer models for the City of Regina.  The models are suggesting highs between 37 and 41 on Thursday:

As the heat moves east ahead of the advancing big blue blob, cooler weather comes in with the upper low right over Alberta by Friday:

This will give us a break from the heat….a ten degree drop in temperatures across BC, Alberta, and much of Saskatchewan.    The chart below shows the cooling Calgarians and southern Albertans can expect starting Friday, and continuing through the weekend:

In Calgary, and southern Alberta, highs will drop to the high 20s on Friday, the mid 20s on Saturday, and the low 20s on Sunday.  The cooler weather won’t last long, as temperatures in the area will return to the 30s early next week as the upper ridge rebuilds.

The only agricultural area anticipating significant rainfall is northwestern Alberta.   In the south, it will remain dry, though isolated thunderstorms are possible each afternoon from Tuesday onward.   Some of those thunderstorms could be severe, with hail.

This map shows accumulated rainfall expected by the end of the day Sunday, July 28.    The white areas in southern Alberta and central Saskatchewan indicate no expected rainfall at all.  By contrast, significant rainfall is expected in northern Alberta, which should help in the fight against forest fires burning in that area:

RELATED: Hail Report: Mild to Severe Hail Damage to Crops Reported Across the Prairies

More specifically:

Monday:

Alberta and Saskatchewan will stay dry all day, but a weak Low pressure system between Winnipeg and Portage La Prairie, will generate some rain over southern Manitoba in the early morning, tapering off in the afternoon.   If showers or thundershowers develop over the Alberta foothills in the afternoon, they are unlikely to move east off the higher terrain.   Scattered showers and thundershowers can’t be ruled out over southern Saskatchewan in the afternoon, but rainfall amounts will be minimal.  Temperatures from southern Alberta to Grande Prairie will climg into the low 30s.   Saskatchewan can expect to reach the high 20s, and low 20s are anticipated for Manitoba.

Tuesday:

As the upper ridge slides east into Saskatchewan, a surface Low will develop over central Alberta, destabilizing the atmosphere and leading to the chance of severe thunderstorms over central Alberta.  Saskatchewan and Manitoba will be sunny and dry.  It will be hot with temperatures reaching the 30s across southern Alberta and southern Saskatchewan.   Highs near 35 will be possible between Calgary and the Saskatchewan boundary.   Cooler air will  nose into northwestern Alberta, where highs will be closer to 20 – similar across Manitoba.

Wednesday:

There will be little change in the weather on Wednesday, as the hot and dry conditions to continue, with instability creating the chance of afternoon showers and storms, particularly in central and southern Alberta, and southeastern Saskatchewan.   Temperatures across southern Alberta and southern Saskatchewan will reach the mid 30s, and Manitoba remains cooler with highs in the low 20s.

Thursday:

This will be the last of the hot days for southern Alberta, and the beginning of a wet period for the northern part of the province.   The surface low that developed in central Alberta a couple of days ago, moves northeast toward Cold Lake, and heavy rain is expected to fall on the forests of northern Alberta, where forest fire fighters will welcome the help.  Some of that rain will extend southward into central Alberta, with the rest of Alberta and Saskatchewan susceptible to afternoon storms.   Manitoba also has a chance, albeit a lesser chance, of afternoon storms.  In the rainy north, a big shift in temperatures, as the once-hot Peace region will see highs of only 10-15 degrees.    Southern Alberta, Saskatchewan, and Manitoba can expect highs in the low 30s.  Parts of southern Saskatchewan have the potential to get close to 40 degrees.

Friday:

A cold front develops from the northern Low, and temperatures will cool down in Alberta and Saskatchewan for Friday and the weekend.   Manitoba remains on the warm side of the front, and temperature will climb to the 30s.  The Low and the front will continue to produce heavy rain in northern Alberta, and there will be rain along the cold front as it crosses southern Saskatchewan, headed toward Manitoba.

Saturday and Sunday:

Cooler weather continues across most of the prairies for the weekend, with highs in the mid 20s, and the northern Low will continue to produce rain.   On Saturday, the Low moves east toward Manitoba, providing more rain for the northern regions on Saturday.  The low rapidly weakens Sunday, and the rain tapers off.    In the south, it’s still dry, and into next week, about to get hot again.

COMPARE TO LAST WEEK: Prairie Weather this Week: July 15