Tag: Snow

Snow Today, Cooler For Week’s End

Brad Leave a comment

Light snow will very slowly taper off through the day today, leaving us with slowly clearing skies and cooler weather.

NAM Sounding valid 4PM Wed Dec 19

A sounding from the NAM for Winnipeg valid at 4PM today. The areas of the line that are coloured yellow denote effective snow making regions in the atmosphere (a combination of temperature & humidity).

Light snow that pushed into the Red River Valley overnight will taper off this evening; despite the fact that the system will be pushing out of the province mid-day, the temperature structure of the lowest 2-3km of the atmosphere will remain highly favourable for the generation of snow, so we’ll likely see additional snowfall through the day today similar to Monday. In total we’ll likely see 4-8cm of new snow through the Red River Valley. Clouds look to begin to break up overnight leading to a cooler night than we’ve had lately with temperatures dropping to around -15°C.

Thursday will bring mainly sunny skies with very little temperature recovery; daytime highs through the RRV will be only -14 or -13°C. The clear skies look to persist through week’s end as cooler air continues to push into the region: overnight lows on Thursday night will drop another couple degrees to about -18°C while temperatures look to climb to only around -15°C again on Friday.

The weekend looks clear but cool, with overnight lows near -25°C and daytime highs near -20°C.

A Seasonal Start To The Week

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Seasonal temperatures will be in place for Winnipeg & the Red River Valley for the start of the week as a continued weak southerly flow keeps the Arctic air locked up to our north.

The CMHR on a Snowy Winnipeg Morning

The Canadian Museum for Human Rights on a snowy Winnipeg morning.

Temperatures will sit near -10°C today through Winnipeg & the RRV, perhaps climbing up to -9 or -8°C briefly. We’ll see light snow through much of the morning with a chance for it to redevelop this evening for a few hours. Accumulations will sit around 2-4cm from this very light, fluffy snow, but it will likely have significant impact on roadways. Combined with the warmer temperatures, fog, and patchy freezing drizzle, some roads in Winnipeg and some provincial highways are already quite icy. As this light, fluffy snow is driven on, it tends to compact to a thin layer of ice; this will likely make it so that some highways, including the Perimeter Highway, side-streets and intersections are quite slippery by the evening commute. Be sure to leave yourself some extra time if you need to drive this evening.

Temperatures will remain fairly steady tonight or even climb a degree or two and another push of warmer air moves in. Once again we’ll likely see dense fog patches and patchy freezing drizzle redevelop tonight as this warm air advances towards the RRV.

Tomorrow, temperatures will climb to about -5°C with scattered flurries through the RRV. Winds will remain light, so it will be another great day to get outside. Some light snow will move through Winnipeg & the RRV tomorrow evening/night as a weak disturbance passes to our south. We’ll get another 1-2cm of snow as temperatures drop back towards -10°C.

Wednesday looks to be almost a carbon copy of today, with some light snow and highs around -9°C. The rest of the week is a little more uncertain; models all hint that the upper-level flow pattern will begin to break down, but how quickly that will happen is uncertain still. While the next few days will almost certainly be cloudy, we’ll probably see the sun start to make an appearance later in the week, if not having the clouds completely clear out. We’ll have more details on the second half of the week on Wednesday.

Light Snow Then A Return To Cold

Brad Leave a comment

Winnipeg seems to have found itself in the firm grip of winter as below-seasonal temperatures dominate the forecast. A low pressure system passing to our south today will bring snow and a slight moderation to our temperatures to near-normal values, but we’ll quickly drop back to well below-normal temperatures.

Storm-total liquid-equivalent precipitation accumulation

Liquid-equivalent (how much water there would be if you melted the snow) precipitation accumulation valid 18Z today.

A weak upper trough will swing through Southern Manitoba today, embedded within a strong northwesterly flow. While temperatures have warmed some 10-15°C aloft over the entirety of the Red River Valley, it looks like the surface warm front will halt part-way between Winnipeg and the U.S. border. Areas south of the warm front (probably areas south of Morris) will be able to tap into a southerly or even southwesterly flow, allowing temperatures to warm possibly as high as -5°C. Unfortunately for areas over the Northern Red River Valley, the warm front will likely remain well to our south, keeping our winds out of the southeast and slowly backing to northwesterly as the system passes by. These wind directions all favour the reinforcement of cold air as they tap into the colder air ahead and north of the low instead of the warmer air south of the low. That means that while there will be a slight increase in temperature from the advection (bringing in) of warm air aloft, a significant portion of the warming taking place over the Northern Red River Valley will be due to heat directed towards the surface from the clouds associated with this low. Highs north of the warm front will sit in the -12 to -15°C range.

Snow associated with this system pushed in overnight and will continue through the morning before tapering off around lunch time. Heaviest accumulations will lay north of the warm front with lighter accumulations south of the warm front. North of the warm front, including here in Winnipeg, we’ll see a total of 6-8cm of light, fluffy snow, while south of the warm front (the Southern Red River Valley) will probably only see a total of 2-4cm. There’s a slight chance that a few lingering flurries will hang on through the afternoon, but accumulations with those would be minimal should they happen.

Temperatures will drop down to around -25°C tonight as the clouds begin to break up and cold air filters southwards again in a northerly flow behind the low. Temperatures struggle to climb above -20°C tomorrow as we find ourselves deep in the cold air once again, some 8-10°C below normal for this time of year.

There are hints that temperatures may begin to moderate on Friday into the weekend, climbing as high as -9°C on Saturday, as a weak south/southwesterly flow develops. I’ll bite my tongue for now as models can sometimes be overly enthusiastic on moving the cold air out of the Red River Valley, but it does look like it’s at least a possibility. If that flow does develop, it’s likely we’ll see another batch of snow late this week as the warmer air pushes in. Until then, keep the long johns handy and be sure to check back in the comments below or follow along on Twitter for updates as the week progresses!

Cold and Calm

Brad Leave a comment

This week will start out cold and fairly benign. Our next chance for snow will come midweek.

Warmer air will be advected into Southern Manitoba on Tuesday night

Warmer air will be advected (moved in via wind) into Southern Manitoba on Tuesday night

After another cold morning on Monday, temperatures will warm up a bit during the day. Highs on Monday afternoon should be in the low to mid minus teens, a significant improvement from Sunday’s minus twenties, but still chilly. The wind will be a bit breezy from the south on Monday, but wind chills values won’t be significantly colder than the air temperature (except in open areas). A weak low pressure system will pass through Southern Manitoba on Monday night, bringing some cloud cover along with it. As a result, temperatures on Monday night will be warmer than those on Monday morning as the cloud prevents heat from escaping from the surface. Unfortunately, temperatures won’t increase much on Tuesday, as we only see temperatures rise a few degrees from the morning lows. Our next little warm-up will begin Tuesday night as an approaching low develops a southerly flow over Southern Manitoba allowing temperatures to rise overnight.

As the low moves into (or just south of) Manitoba on Wednesday, it will bring our next chance for snow. At this point models suggest we may see as much as 5 to 10cm from this system, or perhaps as little as 2cm. Additionally, there are indications that we may see another weak system pass by on Thursday, bringing another small bought of snow. At this point it is too early to say how much snow to expect from these systems, but 5 to 10cm in total for both looks like a good initial “guess”. More information about the potential for snow will be available as the week progresses.