Planting Weather – May Begins

As planting kicks into a higher gear over the next few days, summer-like weather returns to the prairies.   This weekend, it’ll be the warmest weather of the season,  and don’t be surprised if somewhere on the prairies, we get our first 30 degree reading of the year.    However, as one might expect on the prairies, despite the sunny warmth, there will be the ever-present threat of pop-up afternoon showers and thundershowers.

Thursday

Alberta and Saskatchewan

An upper ridge builds over western Canada, clearing out the sky and bringing sunshine first to Alberta and then to Saskatchewan.   At the surface, a centre of high pressure develops over the Alberta Rockies, about half way between Jasper and Banff.    The two ridges, one upper, one at the surface,  mark the initiation of a weather pattern that will bring summer like weather to Alberta and the rest of the prairies in the coming days.    In Alberta, high temperatures could reach the low 20s from Calgary north to Edmonton, and northwest to Grande Prairie.   Elsewhere in the province, highs will range from 15 to 20 degrees.   There will be similar temperatures for western Saskatchewan.   On the eastern side, it’s a cooler day, with highs in the low teens.   The reason for the cooler weather is a disturbance moving through central Saskatchewan, producing rain in a north south line between the Yellowhead highway and the US border.   That line of showers will move to the southeast through the day,  exiting the province in the evening.   Snow is expected on the northern edge of this precipitation band,  near the Manitoba boundary.    Planting in parts of Saskatchewan may be delayed Thursday, but with the return of summer-like weather this weekend, it’s a short delay.    Back in Alberta, weather conditions are ideal for planting, though drought concerns persist in some areas, especially the foothills.    Soil moisture remains plentiful in the southeastern part of the province.

Manitoba

The Low pressure system that produced rain and snow in parts of Saskatchewan will spread some snow from The Pas to Grand Rapids Thursday.   Only a few cm will accumulate, and due to the warm weather, and the warm ground temperatures, there won’t be much of a chance for the snow to accumulate in any significant way.   The band of snow will move southward over the lakes, and quickly fizzle out.  Rain develops in Westman in the afternoon, continuing into the evening.  This is from that same Saskatchewan low, which is weakening as it heads across the international border southwest of Brandon.   An upper trough over the area will provide instability, so convective showers and thundershowers can’t be ruled out.     Highs in southern Manitoba are expected to reach 10 to 15 degrees.

Friday

Alberta, Saskatchewan, Manitoba

The upper ridge moves over Alberta, and the sky in Alberta and Saskatchewan will be mainly clear.  Both provinces will get plenty of sunshine.   Southern Manitoba will also be under a sunny sky, which will allow planting operations to resume.   From the interlake north, it will be cloudy, with some showers scattered through northern Manitoba, well away from agricultural concerns.   The wind will come from the southwest in all three provinces, allowing for a push of much warmer air.    Highs will reach the mid to high 20s all across Alberta and Saskatchewan, with southern Manitoba remaining 5-10 degrees cooler.    The warmest weather, with highs between 25 and 30, will occur along the Bow River valley dowstream of Calgary, near Lloydminster,  in the foothills west of Edmonton, and in the Grande Prairie area.  Similar temperatures are expected in Sasktachewan, between Lloydminster and North Battleford.

Saturday and Sunday

The map above shows potential afternoon temperatures for Saturday.   For some parts of Saskatchewan and Alberta, highs could get close 30 degrees in places such as  Lloydminster, Drumheller, and Kindersley.   It will be the hottest day of the year so far, thanks to a ridge of high pressure that will dominate the three provinces for most of Saturday.

The heat could lead to the development of a thermal Low pressure system in southern Alberta,  which may lead to instability and some afternoon thunderstorms, especially northwest of Calgary, and west of Edmonton toward Jasper.   The low will head northeast into Saskatchewan during the evening, but will leave rain behind for central and northern regions of Alberta.   There should not be any interruption to planting operations south of Red Deer, but with increasing instability, a few pop up showers or thunderstorms in the region can’t be ruled out.

Colder weather will rush into  Alberta from the west on Sunday, and as one air mass replaces another, there will be wet weather for central and southwestern Alberta, where it will be much cooler, with highs in the 10 to 15 degree range.   Meantime, Saskatchewan and Manitoba will continue with very warm weather, as  highs between 25 and 30 are again possible in central Saskatchewan, and southern Manitoba.

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