Prairie Weather (Rural Roots Canada) – It’ll be a wet week across the prairies, which will be great for fall seeded crops, but will yet again interrupt the harvest. Fortunately, crop reports for all three prairie provinces indicate the harvest is running well ahead of normal.   It will be near or slightly warmer than average, but big rainfall is expected in all three prairie provinces this week, as indicated by the purple shading on the maps on the right side of this chart:

An upper level low will arrive in the US Pacific Northwest, and eject moisture into Idaho, Montana, and the Canadian Prairies, especially on Tuesday and Wednesday.   Those two days could be quite blustery, with heavy rain, strong winds, and thunderstorms across the southern prairies.   Details to follow below on the day to day breakdown.

The rain this week should help with the persistent short term drought that continues in southern Saskatchewan.   The latest drought monitor shows improvement for parts of Alberta and Manitoba, thanks to August rain.   Almost all of Saskatchewan, though remains in drought:

The only prairie locations still in extreme drought are in northwestern and central Alberta. Unfortunately, those two areas missed out on some fairly heavy rain that fell this past week.  While Saskatchewan and Manitoba didn’t see widespread significant rain, southern Alberta’s harvesting operations had to pause last week, due to heavy rain in the eastern half of southern Alberta.  (Aqua on the map below)

Here are some rainfall totals from last week in Alberta:

The map above shows while Alberta had a significant rain event, Saskatchewan and Manitoba remained quite dry, though that will change this week, as all three prairie provinces will experience significant rain.

According to the latest crop reports, the harvest is running way ahead of schedule.   In Alberta, the overall harvest is 55 percent complete.  In the south, combining is 72 percent complete.   In Saskatchewan, the harvest is 61 percent complete, again running well above average.  In Manitoba, the harvest is 40 percent complete, although the number is skewed by low completion for canola.    Some Manitoba crops, such as winter wheat, fall rye, and field peas are 100 percent harvested.

Of course, the speedy harvest means farmers are so far winning the race against frost.    We’re at that time of year when we can expect the season’s first frost.

Here are some average first frost dates for the three prairie provinces, courtesy of T&T Seeds:

Manitoba:

Saskatchewan:

Alberta:

READ MORE: Hail Report: Isolated Hailstorms Cause Minor Damage to Crops

This week’s weather:

Monday:

The calm before the storm.  As an upper level low on the coast drops rain to coastal BC, the prairies will be dry until the afternoon, when moisture pushes northward from the US, generating sprinkles in southern Saskatchewan, and steadier rain in southern Manitoba.   Highs will be in the low to mid-twenties across the prairies, except for southern Saskatchewan and southeastern Manitoba, where it could warm to the high twenties.  It may even hit 30 around Morden, Winkler, and Emerson!

Tuesday:

Things start to get a bit messy.    Areas of heavier rain and thunderstorms develop in central Saskatchewan and southern Manitoba, thanks to a Low pressure system in eastern Montana.  The low will also push moisture up against the southern Rockies, along the BC boundary. Severe thunderstorms are possible over southern Saskatchewan and southern Manitoba.   Despite the arrival of rain, high temperatures in almost every location will be similar to those on Monday.

Wednesday:

The Montana Low takes a northward turn, headed for southern Saskatchewan, and the rain and storms intensify in southwestern Saskatchewan and southeastern Alberta.   The low becomes stronger as the day progresses, and the weather gets stormier.    Thunderstorms and severe thunderstorms are possible again over southwestern Saskatchewan and southeastern Alberta, where heavy rain is possible.  In parts of southern Alberta and southern Saskatchewan, the rain may fall sideways, as strong wind is expected to develop.   Moderate rain will fall elsewhere in southern Alberta, west of Brooks.  Rain in southeastern Alberta will continue to fall hard late into the night.  With all the rainy weather in Alberta and Saskatchewan, highs will only reach the mid to high teens in most areas.   It will be warmer in Manitoba, with highs in the mid-twenties.

Thursday:

By midday Thursday, the rain event is over for Alberta, the Low weakens as it starts to make a move out of Montana, and it continues to rain in Saskatchewan.   A trough will develop between the Montana low and another in Nunavut, and along the trough, the rain will spread into central and northern Saskatchewan and northwestern Manitoba.    Showers or light rain are possible in southern Manitoba.   As the day progresses, the Montana low will cut across North Dakota, and end up near Boissevain, Manitoba.   That will cause the light rain in Manitoba to intensify, and there may be nocturnal thunderstorms in the Red River Valley.   Most of the prairies will be cool, as expected.   Highs in Saskatchewan and Alberta will hover around 15 degrees, and it won’t be much warmer than that in Manitoba.

Friday:

The Manitoba low continues to produce rain for southern Manitoba, and by the end of the day, it will stretch northward toward Churchill.  Meantime, another Low develops in the foothills of the Rockies in southern Alberta, and that will kick off some rain in central Alberta, and in the foothills northwest of Calgary.   This area is in serious need of moisture, as it remains in extreme drought (see drought monitor map above).  However it appears accumulations from this system will be light, as the rain quickly moves on to the Fort McMurray area.   Rain continues to fall in Manitoba Friday night and early Saturday morning.  The cool weather continues, with highs across the prairies expected to remain in the teens.   In central Alberta, near Edmonton, it may be as cool as the single digits for afternoon highs.

Saturday:

The train of Lows continues, with another developing near Kimberley, BC, spreading rain across southern Alberta, south of the Trans-Canada Highway.   The rain begins to taper off in Manitoba, though it’s a very slow process, and light rain could continue over the agricultural land in Manitoba for the bulk of the day.  The eastern prairies will warm to the high teens or the low twenties, but back in Alberta, it’s cold.  Single digit highs are expected in the foothills and across the south.    Eastern and northern Alberta may reach the double digits, but barely.

Sunday:

Rain or showers are expected across the southern prairies, as the stretch of wet weather continues.    In Alberta, the rain will extend as far north as Carstairs, and west into the foothills and Rockies.   A high pressure system develops in northern BC.   This will pump some cold air southwestward toward Alberta, and in some areas, frost cannot be ruled out.   Because of this invasion of cold air, rain will likely turn to snow at higher elevations.   It would be wise to pay attention to weather forecasts in Alberta for current information on any snow or frost threat.    Saskatchewan and Manitoba will not be affected by the cold outbreak further west.  However, it will be another chilly day, with temperatures across the prairies in the low double digits.

BONUS MAP:

And here’s a bonus map……the temperature outlook for pre-sunrise Monday Sept 23.   This could be the morning of the first frost in Alberta and part of Saskatchewan.   The red and blue colors denote temperatures below zero!    Brrrr….

COMPARE TO LAST WEEK’S PRAIRIE WEATHER REPORT: Prairie Weather this Week: September 9