Prairie Weather (Rural Roots Canada) – Drier weather returns to the southern prairies this week, and La Nina conditions may return this fall
La Nina conditions are expected to redevelop this fall. It looks, though, like it won’t last very long, unlike last year, when La Nina persisted through the winter. The latest forecasts from National Oceanic and Atmospheric Administration in the US, suggests La Nina is building now, and will be in place from September to December, and perhaps January, when neutral conditions return for the remainder of the winter.
Typically, La Nina brings cooler and wetter weather to the Canadian prairies, with increased snowfall, especially in Alberta and parts of Saskatchewan. But not always. Last winter’s La Nina was a precursor for spring drought on the prairies, which carried over into the summer on the eastern prairies. With this next La Nina being so short-lived, the impact is expected to be minimal. Those hoping last year’s La Nina would be followed by El Nino this winter will be disappointed.
Much drier weather returns to Alberta this week, while measurable rain falls in Saskatchewan, and heavier rain persists in Manitoba. The maps below show the expected rain accumulations up until the end of the day Sunday Aug 24:
The first map gives us a good look at Alberta. It will be very dry in the southern half of the province this week, with many areas getting no rain at all:
Rain will be scarce this week in southern Saskatchewan, with more significant rain expected in Manitoba:
We’re now into the second half of August, the time when the severe weather season dies down. This is not to say there won’t be any more storms, but we can expect fewer of them between now and the end of the month.
It’s also the time of year, when we begin to pay much more attention to overnight lows. It will likely be at least another month before we’re really into a hard frost risk, but the trend toward colder nights is getting underway.
Here is the daily breakdown for the next week across the prairies:
Monday
Alberta
It will be mostly dry across southern and central Alberta, which will be good for those cutting hay or harvesting early. A weak low will develop in central Alberta during the day, and could generate a few showers in central Alberta particularly along the Saskatchewan boundary north of Lloydminster. Late day showers can’t be ruled out in the Edmonton area. Expect highs of 20-25 in central Alberta, and in southern Alberta, east of Highway 23, expect afternoon temperatures in the high 20s, close to 30 degrees in the southeastern corner of the province. Monday night, single digit lows are likely in the western half of the province, especially at higher elevations.
Saskatchewan
Conditions could become unstable in southeastern Saskatchewan during the afternoon on Monday. Severe thunderstorms and even tornadoes are possible in the area. Elsewhere, it will be mostly dry as high pressure builds over the province. Highs will reach the mid to upper 20s in the south, and the low 20s in the north. Late in the day, a disturbance in the Lloydminster area will track into northcentral Saskatchewan, providing evening rain to the region, with a chance of storms.
Manitoba
Morning rain in southern Manitoba tapers off, though rain will continue in the northern Interlake through much of the day. The sun comes out, but the atmosphere remains unstable. Southwestern Manitoba will be ar risk for severe weather, including strong wind, hail, and possible tornadoes. Highs in southern Manitoba will reach the mid to upper 20s.
Tuesday
Alberta
It will be another dry day in a dry week for southern Alberta. Similar conditions are expected in northern Alberta though some widely scattered showers and possible weak thunderstorms may develop northwest of Edmonton in the afternoon. No significant rainfall is expected. And, as high pressure dominates, any effort at rainfall may be quite a struggle. Some parts of the province will be warm. Other parts will be hot. In northern Alberta, expect highs from 20-25 degrees. Central Alberta and the southwest should reach 25-30. And in southeastern Alberta, from Lethbridge to Medicine Hat and the surrounding areas, temperatures should peak in the 30-35 degree range. Expect heat warnings there.
Saskatchewan
It will be a hot day in southern Saskatchewan, with many areas south of the Yellowhead highway reaching highs in the low 3os. To the north, highs in the mid to high 20s can be expected. The heat will generate some instability, and randomly scattered thunderstorms are possible across central and eastern areas of the province. Expect heat and storm warnings.
Manitoba
It will be another hot and humid day in southern and eastern Manitoba, with highs just below 30 degrees. Severe weather is not expected, though there may be some late day thunderstorms near the Ontario boundary. Rain can also be expected during the day in the northern Interlake.
Wednesday
Alberta
For Alberta, Wednesday brings perhaps the best chance of the week for rainfall. A weak low pressure system near Medicine Hat will cause rain to fall in the southeastern corner of the province, and north along the Saskatchewan boundary, all the way to the Northwest Territories. Central Alberta is likely to get some rain in the morning as well. The low will continue to weaken as it moves toward Saskatchewan, but scattered showers may continue through much of the day in southern Alberta.
In the far northern part of the province, afternoon thunderstorms are likely, and some may be severe. In the south, highs will be in the mid to high 2os, and in the low 20s in central and northern regions. There will be considerable cooling in the north, when the rain develops in the afternoon. Single digit overnight lows can be expected in central Alberta Wednesday night.
Saskatchewan
Morning rain in southwestern Saskatchewan tracks to the northern part of the province, where it will intensify in the afternoon. No significant rainfall is expected in southeastern Saskatchewan. Showers and thunderstorms though, are possible in east central Saskatchewan especially toward the Manitoba boundary. Cooler air arrives, highs mid-20s.
Manitoba
It will be another typically warm day in southern Manitoba, with highs in the mid 20s. In the morning, rain can be expected in southwestern Manitoba and the Interlake. By afternoon, most of the wet weather has tapered off in the southwest, and intensified in the Interlake, with thunderstorms possible in the central part of the province. Southeastern Manitoba should stay dry, though thundershowers caused by instability will be something to watch for near the Ontario boundary.
Thursday and Beyond:
A storm system associated with a cold front sweeping across the Prairies, that produced severe weather in Alberta Wednesday, crosses the eastern prairies Thursday. The active pattern brings a final round of heat and storms to Saskatchewan and Manitoba on Thursday before high pressure settles in, bringing drier conditions and good opportunities for early harvesting work by Sunday.
The map below shows dry weather through the weekend in Alberta and much of Saskatchewan’s agricultural territory. Rainfall totals will be high in Manitoba, with much of that moisture coming Thursday with the passage of the cold front.
This period of dry weather will be helpful for those who have begun harvest operations. As the old saying goes, “Make hay while the sun shines”. It won’t stay dry forever. If you missed it, we discussed the return of La Nina later in the harvest season here.
Overview
Thursday, a strong surface low in nothern Ssskatchewan dominates weather all across the prairies. A cold front from the low will create stormy conditions on the eastern prairies. A warm front will send some moisture into Ontario, and a trough curving back into northern Alberta will produce heavy rain for the forests of northern Alberta and northern Saskatchewan. There will also be heavy rain near the centre of the Low itself. Toward the weekend, the Low will slowly move east, and drier weather returns to the prairies.
Thursday
Alberta
It will be a dry day over Alberta’s agricultural regions, following the severe weather that dumped heavy rain and hail across the southeastern part of the province on Wednesday. Expect plenty of sunshine, but not a lot of heat. The sky cleared behind a cold front, and temperatures wil be near long term averages. Highs in most of Alberta will be in the upper teens to low 20s, though south of the Trans Canada Highway, highs in the mid 20s are possible.
Saskatchewan
Early showers and storms are possible in southeastern Saskatchewan, as the cold front rapidly moves east. By the afternoon, expect rapid clearing, and a sunny end to the day. As mentioned in the overview above, there will be heavy rian in northern Saskatchewan, with some areas getting 50 mm or more. This is well north of agricultural territory. Following the passage of the cold front, highs in southern Saskatchewan should reach the low 20s at best.
Manitoba
Strong storms with heavy rain and hail will sweep across southern Manitoba Thursday, due to the passage of a cold front associated with a low in northern Manitoba. The Low is centred near Lynn Lake, where more than 50 mm of rain are possible. In the south, high rain accumulations will be localized. Expect highs in the low to mid 20s. Some of the Thursday storms may be severe. Monitor warnings here.
Friday
Alberta
All of Alberta can expect dry weather Friday, and most of the province will be sunny. There will be some cloud over the northern forests, but in central and southern regions, high pressure gives us sunshine – good drying conditions for swaths and hay bales. In the morning, expect cool, single digit low temperatures. Across the province, afternoon highs will reach the low to mid 20s.
Saskatchewan
As the rain producing Manitoba low moves east, it will pull its rainfall away from northern Saskatchewan. The south will be dry, and there will be a north wind. That will mean cooler than average temperatures in most of the province, with highs in the high teens or low 20s.
Manitoba
Still unsettled. Southern Manitoba can expect a mix of sun and cloud with a chance of storms, while northern regions continue to receive steady rain before it tapers off later in the day. The northern Manitoba low pressure system will move in the general direction of Hudson Bay during the day, and the area of heaviest rain will move slowly from west to east. This is all well to the north of agricultural regions. However, the entire province will be affected by a brisk north wind that will keep high temperatures below 20 degrees.
Saturday
Alberta
Saturday’s Alberta weather will be a repeat of Friday, with dry, sunny weather across the province. Most of the south will be wind-free. Highs will reach the low to mid 20s, except in southeastern Alberta. South of the Trans Canada Highway and east of Highway 2, highs should make it to the high 20s.
Saskatchewan
Sunshine is expected all day in the south, as rain continues to taper off in the north. By the end of the day, the entire province returns to dry weather, and the northern sky will also clear out. Across the province, highs will be pleasantly cool, near 20 degrees.
Manitoba
The rain in central and northern Manitoba continues its very slow movment east, as the the once-dominant Low moves into Ontario. Rain will continue Saturday in east central Manitoba, while it stops elsewhere in the province. West of the Red River, most agricultural areas will see sunshine, but it will be another cool day with highs below 20 degrees.
Sunday
Alberta, Saskatchewan, Manitoba
Excellent harvest weather continues in Alberta, and takes hold in the other two prairie provinces. All three provinces will experience a sunny day, as a large surface ridge of high pressure takes hold. This is the kind of dry, sunny, warm weather system that has so far been absent this summer across the prairies. Earlier in the summer, we’d expect hot weather with this kind of weather pattern. But we’re now into late August, so we don’t expect any 30 degree tempratures. Highs in southern Alberta should reach the high 20s. In central and northern Alberta, along with Saskathcewan, highs will be in the low 20s, and in Manitoba, it will be cooler, with highs in the high teens to 20 degrees.
It could be quite cold in southeastern Saskatchewan late Sunday night and early Monday morning, with lows between 0 and 5. Frost is not expected, but it’s getting close!
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