Cool Weekend Ahead

Arctic air will keep temperatures cool through the weekend with daytime highs some 5-7°C below normal. Scattered flurries will be common through the weekend, while a significant lake-effect snowfall event will impact portions of the Whiteshell and Eastern Manitoba.

850mb Temperatures Valid Saturday Morning

850mb temperatures valid Saturday morning. A deep pool of Arctic air will flood across the Prairies this weekend.

As the low that brought rain to Southern Manitoba the past few days pushes northwards into Hudson Bay, it will intensify quite considerably1 and induce a strong northwesterly flow over the Canadian Prairies. This cold air will likely produce isolated scattered flurries, however the largest effect will be strong lake-effect snow bands, primarily from the basins of Lake Winnipeg. These lake-effect bands will mainly effect the Bisset region and slowly push northwards towards Berens River as the winds back slightly to westerly through the weekend. Substantial amounts of snow are possible with these bands, with the potential for anywhere from 15-30cm of snow possible in areas that see a band have a particularly long residence time over them.

Daytime highs over the next few days will sit within a degree or two of 0°C, with overnight lows near -6 or -7°C. No significant improvement in temperatures is expected until potentially early next week as a low pressure system moves through the Central Prairies and brings ever so slightly warmer air back to the region.

  1. It’s currently forecast to deepen from a 982mb low this morning to a 967mb low tomorrow morning. 

Cooler Air Pushing Southeast Across Southern Manitoba

The powerful low pressure system that has brought rain to Winnipeg over the past couple days and is bringing 10-20cm of snow to portions of Northern Manitoba has pushed north and east of the Red River Valley, setting the stage for cooler air to filter into the region.

700mb Temperatures for Thursday Morning

NAM forecast of 700mb heights & temperatures valid Thursday morning.

The Red River Valley will be moving into a strong northwesterly flow aloft that will advect cooler air into the region. While earlier in the week, models were projecting a very potent arctic blast, things have become a little more pleasant due to a more significant amplification of the upper-level pattern. The net result of this is a cut-off upper low over the central Prairies that will, in effect, block the coldest air from being able to push southwards. This will give us more cloud than sun with daytime highs near 5 or 6°C through the rest of the work week.

The upper low begins to push eastwards for the weekend, allowing slightly cooler temperatures to the area for the weekend, with highs near 0°C, and a chance of some light snow. Accumulations will be light-to-none throughout the RRV, however a few cm may pile up in the Interlake region.

More Active Weather

More active weather is in store for this week with multiple chances for precipitation. The question is whether that precipitation will be solid or liquid.

Low pressure system passing to the south-east on Thursday

A low pressure system is currently expected to pass to our south-east on Thursday, generating minimal impacts in Manitoba

The weather to start the week will be fine, with temperatures generally in the high single digits on Monday and perhaps a few double-digit readings here and there. There will be increasing cloudiness during the day as a weather system approaches. This system will begin to spread rain over Southern Manitoba on Monday night with precipitation persisting into the day on Tuesday. Highs on Tuesday will remain very similar to Monday, but the rain will make it a considerably more miserable day. Total accumulations from this system will generally range from 5 to 15mm. As Tuesday’s system departs our region on Wednesday, cooler air will sweep in from the west making for a chilly and windy middle of the week. Temperatures on Wednesday will be in the mid single digits with a gusty west wind.

There has been much talk about the weather for later this week. Some models have been showing a significant Colorado Low system hitting portions of Manitoba on Thursday and Friday. However, other models show little or no precipitation for us later this week. At this point the consensus seems to be that it is unlikely Southern Manitoba will be getting a major blizzard later this week. Most models depict a moderate strength low system sliding past us through Minnesota and up into North-Western Ontario, perhaps bringing a few flurries or rain showers to Southern Manitoba, but not a major winter storm. Some models still show a fairly deep low pressure system to our east over Northern Minnesota and North-Western Ontario later this week, but it looks like it will be sufficiently far away to prevent us from seeing its main impacts. So at this point it appears unlikely that we’ll be seeing any significant amount of the white stuff later this week. However, expecting the unexpected as always a good saying to live by in the weather business.

Lingering Showers Give Way to Unsettled Weekend

A few lingering showers will persist through the Red River Valley this morning as the low pressure system that has been bringing us rain the last couple days slowly pushes eastwards. Conditions won’t improve too much, however, as we’ll be dealing with unsettled weather, albeit a little dryer, through the weekend.

Rainfall accumulations through the day today.

This 12 hour rainfall accumulation map shows the total rainfall that the RDPS model is forecasting for the daytime today.

Showers will slowly taper off through the Red River Valley today from west to east with only a further 2-4mm in rainfall accumulations. This system has brought hugely varying rainfall amounts across the RRV, with general amounts from 20-60mm across the Red River Valley. After spending several months in a row with below-normal precipitation, this system has pushed Winnipeg back to above-normal accumulations for October, which will begin to chip away at our deficit for the year. Winds will also taper off through the day today as we move to a high of only 7 or 8C.

Saturday will be a mainly cloudy day with a slight chance of showers and a high near 11C.

A frontal wave pushes across Southern Manitoba on Sunday, occluded from the parent low that will be captured over Northern Saskatchewan by an upper low in the area. Some uncertainty exists to the amount of precipitation associated with this wave as it moves through. Some models have next to no precipitation, while the GDPS is suggesting as much as 10-15mm of rain. My personal feeling is that we’ll likely see some rain push through with general amounts in the 4-8mm range across much of the RRV. We’ll keep an eye on this system and provide some updates through the weekend in the comments below. Sunday will likely be mostly cloudy again, with a high near 10C.

The biggest weather feature next week looks to be the potential for a significant low pressure system to push into North Dakota, bringing rain, snow, and potentially blizzard conditions to the Red River Valley for the second half of the week. That’s a long ways away, though, and a lot can change between now and then. We’ll be sure to follow this potential system closely through the week ahead.