Prairie Weather (Rural Roots Canada) – Thunderstorms! Just a bit late, the storm season begins on the prairies. And…we may see 30 degree temperatures this week.
A fast-moving upper trough swings across Saskatchewan and into southwestern Manitoba on Monday, with the potential to produce thunderstorms in an area already impacted by localized flooding. A second system could move through later in the week. In addition to rain and lightning, the storms will produce gusty winds and perhaps small hail. Eastern Saskatchewan is already dealing with flooding. There have been road closures due to flood waters in recent days, and as of this writing, there are still three closures in the area:
The map will change, possibly daily, through the week, so if you’re concerned about road closures and flooding as the storms roll through, consult Highway Hotline before heading out.
While no major organized storms are forecast for the prairies this week, the atmosphere becomes unstable again on Wednesday and Thursday, leading to the possibility of more isolated thunderstorms with strong winds and possible hail. The risk of severe storms is minimal, but not zero.
Here’s how it plays out:
Below is a map of surface weather conditions early in the morning on Sunday, May 10:
The dashed blue line bisecting Alberta from north to south is a trough of low pressure. The high over western Manitoba will get out of the way, allowing that trough to move eastward, and it will be in Saskatchewan by Monday morning. There, it will do its dirty work, producing the aforementioned thunderstorms. Look for the greatest precipitation in the northern grainbelt, as a Low forms just northwest of Saskatoon. A weak trough out of that low could produce some isolated thunderstorms to the south, between the Yellowhead Highway and the US border. This is the first of multiple chances for thunderstorms across the prairies this week.
Seeding is well underway now across all three provinces, and all three have begun issuing crop reports. Alberta is starting the season well, with 50.6 percent of surface soil moisture rated as good, 17 percent as excellent. The Saskatchewan crop report dates back to May 4 and shows significant delays in planting due to flooding. As of May 4, 3 percent of seeding has been completed, compared to the long-term average of 12 percent. The most recent Manitoba crop report was issued May 5 and was reported in the May 7 midweek update.
Monday
Peace Region
Sunshine, a west wind, and temperatures in the high teens – above average. The wind will gust toward 50 km/h during the day, which may impact seeding operations. Dry, exposed soil may be blown around by the brisk wind. The windy conditions are caused in part by a pressure gradient between a central Saskatchewan low and a west coast high.
Alberta
Vort Max, or vorticity maximum, is a term used all the time among meteorologists. It describes an area of maximum spin in the atmosphere, measured at 500 millibars, or about 18,000 feet off the ground. The energy caused by the rotation frequently leads to rain and thunderstorms. And, that’s what’s expected to happen Monday in a localized area in southern Alberta:
Green on the map above shows where rain or thunderstorms are possible, but they will be isolated and won’t cover the entire shaded area. Blue on the map indicates that at higher elevations, the precipitation will fall in the form of snow. All across Alberta, it will be a seasonably cool day, with highs in the 16 to 19 degree range.
Saskatchewan and Manitoba
Showers and thunderstorms will accompany a low-pressure system as it moves through central Saskatchewan and into Manitoba during the day. The animated map below shows the most likely location of the showers and storms. The loop starts at midnight Monday morning, and continues for 24 hours:
With this system, expect thunderstorms, localized heavy rain, gusty winds, and small hail. Pay close attention to weather warnings, as a severe event, while unlikely, cannot be ruled out. Areas that get the rainfall can expect anywhere from 3 to 10 mm, depending on how close they are to the storm cores. Saskatchewan, with highs between 17 and 20, will be warmer than Manitoba, where temperatures in the south will be in the lower double digits. Manitoba remains much cooler than average.
Tuesday
Peace Region
It’s another uneventful weather day in an uneventful week for the Peace. As high pressure takes over Western Canada, expect plenty of sunshine, with highs near 20 from Fort St. John to Grande Prairie. It will be four or five degrees cooler toward Tumbler Ridge. The wind will be light, and there will be no weather barriers to seeding and other field work.
Alberta
Across Alberta, it will be a quiet weather day, with perhaps some cloud near Waterton. Otherwise, expect a mainly sunny sky across the province with highs in the low to mid 20s. The wind will be light, and there are no weather concerns for seeding operations.
Saskatchewan
After Monday’s active weather, Tuesday will be a calm day across Saskatchewan, with plenty of sunshine across the entire province. Due to Monday’s rain, some fields may be muddy in the morning, but should dry out by afternoon due to the abundant supply of sunshine on Tuesday. South of the Yellowhead highway, high temperatures will reach the low 20s. North of the Yellowhead, expect temperatures to peak between 13 and 20 degrees.
Manitoba
Mid double-digit highs can be expected in Manitoba on Tuesday, as the province will be influenced by a northerly flow that follows the passage of the disturbance that created Monday’s wet weather. In southern Manitoba, the wind is expected to be quite strong at times, gusting at times to 60 km/h. This could affect seeding, especially south of the Trans Canada Highway. Weather charts indicate the wind will last all day, before tapering off in the evening. Overnight, frost will not be a concern, as temperatures will remain above zero.
Wednesday
Peace Region
The Peace Region may be the sunniest part of Alberta and BC on Wednesday. It won’t be 100 percent sunshine, but the clouds that form are unlikely to completely cover the sky and are unlikely to produce precipitation. Temperatures will peak near 20 degrees. While the wind may become gusty at times, it’s unlikely to disrupt any field operations.
Alberta
After a couple of stable days, the weather in Alberta becomes more active again on Wednesday. The wind will pick up, and while it may be gusty in parts, no severe wind issues are expected. That said, there may be times when you’d want to pause seeding operations briefly due to the wind. This applies mainly to areas near Edmonton, Fort Macleod, and Coronation. There will be a big range in high temperatures across the province on Wednesday. Northern Alberta will reach the mid to high teens. Central and Southern Alberta will reach the high twenties, and as the map below shows, parts of southeastern Alberta could see their first 30-degree readings of the season:
Saskatchewan
Much of Saskatchewan will have a summertime feel on Wednesday, with temperatures reaching the high 20s, even climbing to 30 near the Alberta boundary. Quite often, that kind of heat brings instability and fuels thunderstorms. Not this time. For most of southern Saskatchewan, it will simply be a sunny, warm, or even hot day. In the afternoon, though, expect clouds to come in from the west and overtake the province overnight. No rain is expected, though. The late-day clouds are associated with a developing low near Rosetown.
Manitoba
Manitoba’s agricultural areas will be under sunshine on Wednesday, exactly the kind of weather needed so farmers can catch up with their seeding. However, it’s still a bit cool, especially compared to the weather to the west. Highs in western Manitoba will reach the low twenties. Elsewhere in the province, 20 degrees won’t be achievable. See the map above. A low building in Saskatchewan will spread more cloud into Manitoba on Wednesday night, but precipitation is not expected in southern and central Manitoba.
Thursday
Peace Region
The Peace Region cools off a bit on Thursday, but highs of 16 or 17 degrees are near the seasonal average. While there is a chance of rain in the north Peace during the afternoon, most of the region will remain dry under a partly cloudy sky. Good seeding weather will continue for another day, though there may be some brisk afternoon wind on the Alberta side of the Peace Region. The wind will be from the west.
Alberta and Saskatchewan
Seeding may have to be paused in eastern Alberta and Saskatchewan south of the Yellowhead highway, due to strong winds. A low-pressure system in west-central Manitoba will create strong winds across southern Saskatchewan and eastern Alberta on Thursday. Due to the circulation around the low, the wind will come from the northwest. Despite the direction and strength of the wind, it should end up being a rather warm day. In Alberta, west of Highway 2, expect highs in the 17 to 18 degree range.
East of Highway 2, and all the way through southern Saskatchewan, temperatures will climb to the low 20s. East of Highway 2, it will be dry. The cooler conditions west of Highway 2 are attributable to a disturbance that will cause showers to develop along the foothills. There won’t be a lot of rain, with most areas getting less than 5 mm.
The wet weather will be confined to the foothills and is not expected to move east. Northern Alberta and Northern Saskatchewan can expect wet weather, though, with most areas receiving 5 mm of rain. However, under convective storms, local rainfall amounts will be higher.
Manitoba
Manitoba will also have rather dry weather, under partly to mainly cloudy conditions. And, it will be one of the hottest days so far this season, with highs ranging from 26 to 31 degrees in southern Manitoba and the Interlake. Further north, well away from agricultural concerns, it will remain cold. The far north may remain below freezing all day. The biggest weather issue in the south will be wind. A strong south wind will reach into the Interlake from the US. It will not bring in any severe weather, but there may be a few showers and non-severe storms in the afternoon south of Brandon.
Friday
Peace Region
Friday in the Peace Region looks cool and unsettled compared to earlier in the week. Expect daytime highs around 15, with cloudy skies and a chance of light rain or drizzle, especially from morning into the afternoon. Overnight temperatures are forecast to drop to about 4. There is a lot of uncertainty, so check back here on Thursday for updated information.
Alberta
Expect a mix of sun and cloud in southern and northern Alberta, with mainly cloudy conditions across the centre of the province. It will be a considerably cooler day with highs in the mid to high teens. Again, rain or showers may develop west of Highway 2 and south of Highway 11. Higher elevations can expect snow, and that includes the Icefields Parkway. The exact location of the wet weather cannot yet be determined, but we will figure it all out in the Thursday update later in the week.
What we can tell you now is that any rain that falls over agricultural regions of southern Alberta will be minimal – close to just 1 mm. Another disturbance will bring heavier rain to parts of northern Alberta, north and northwest of Bonnyville.
Saskatchewan
Friday brings dry weather and highs in the low 20s to southern Saskatchewan. Some midday showers are possible near and northwest of Saskatoon, but accumulations will be minimal. Any disruptions to seeding in this area will be temporary, with the rain moving out by early afternoon. Wind may become a concern throughout most of the day south of the Yellowhead Highway. While sustained wind will be in the 20 km/h range, gusts could easily reach 30.
Manitoba
Southern Manitoba will be impacted by gusty winds on Friday, and it may be briefly disruptive to seeding. Most of the day, it will be sunny and breezy with no significant precipitation expected. It will be cool, South of the Trans Canada Highway, high temperatures will reach the high teens and low 20s. North of the highway, it will be considerably cooler, with temperatures reaching the low double digits at best.
Saturday and Sunday
On the weekend, a low that forms in eastern Alberta on Saturday will cross the prairies into Manitoba, and kick off more showers and thunderstorms. It’s too early to nail down specifics on the rainfall, but as indicated in the map below, accumulations should be minimal. The chart shows the rainfall expected on Saturday and Sunday:
Temperatures on the weekend will be near the seasonal average, with highs both days in the high teens or low 20s.
