Tag: alberta clipper

Warmer, but not Warm

Brad Leave a comment

Warmer weather will be more common in Southern Manitoba this week, but that’s not to say it will be warm weather. Rather, it will just feel warm relative to the arctic weather we’ve experienced lately.

Alberta Clipper snowfall map on Monday

The Alberta Clipper that will bring snow to Southern Manitoba on Monday

The weather this week will be characterized by a semi-zonal flow aloft. A zonal flow is when the jet stream moves west to east, which tends to give us neither really cold weather nor really warm weather. A series of small disturbances will ride along the jet stream, bringing us a couple chances for snow through the early part of the week.

Monday

Monday
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Light Snow
-12°C / -17°C

An Alberta Clipper system will roll through Southern Manitoba on Monday bringing more snow along with it. This will be a fairly weak clipper, without much moisture to work with. At this point it looks like the “heaviest” band of snow will pass somewhat south and west of Winnipeg, where up to about 5cm could fall. In Winnipeg and area amounts will in the 2-4cm range. There won’t be much in the way of wind with this system, so its affects will be limited to adding more slippery sections to roadways.

Tuesday

Tuesday
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Mainly Cloudy
-10°C / -15°C

Tuesday will be a fairly nice day overall, with light winds and mainly cloudy skies. Temperatures will be fairly close to seasonal values, with highs in the upper single digits or lower double digits (below zero of course).

Wednesday

Wednesday
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Snow
-7°C / -18°C

It appears that we’ll see yet another Alberta Clipper on Wednesday. It will bring snow once again, with accumulations probably being a bit higher than those seen on Monday. It’s hard to say exactly how much we might get from this clipper, but an early guess would be anywhere from 4 to 8cm in Southern Manitoba. Check the comments for an updated forecast for Wednesday over the next couple days.

For once there may be something of interest to talk about in the long-range. There have been numerous indications over the past week that we may be heading toward a more prolonged warm period that could exist through mid-February. The Climate Prediction Centre, NAEFS ensemble, ECMWF, and arctic oscillation predictions are all in line with milder weather for the early to mid-month period. They don’t give a clear indication of how mild it could get, but certainly arctic outbreaks like those experienced in January could be much harder to come over the next while.

The Deep Freeze Gives Way to A Mixed Weekend

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While temperatures across the Red River Valley this morning are extremely cold, a developing series of major low pressure systems set to impact Alaska will be responsible for pushing us out of the deep freeze and back towards more seasonal temperatures for next week.

12hr. QPF valid Saturday at Noon

The GEM-REG is showing around 1–2cm of snow across the Red River Valley by midday on Saturday.

Friday


Sunny. Increasing cloud overnight.
-24°C / -28°C

Sunny skies will dominate the Red River Valley for most of the day today as we remain under the influence of the Arctic high. Entrenched in the cold air under this high, temperatures today will climb up to about –24°C; this is some 13°C below the “normal”[1] temperature for this time of year. The strong northwesterly flow aloft that’s brought our cold air back will begin to waver tonight as a weak disturbance ripples down the jet stream towards Southern Manitoba. An Alberta clipper will rush across the Prairies tonight, pushing clouds into Southern Manitoba through the overnight period and preventing our overnight lows from dropping to anywhere near where they bottomed out last night. Overnight lows will likely sit at around –27 or –28°C tonight through most of the Red River Valley.

Saturday

Saturday

About 2cm of light snow.
-16°C / -28°C

As the Alberta clipper pushes through on Saturday, a broad area of light snow will move through the Red River Valley. This system will be rather moisture-starved with only ¼ to ½” of precipitable water to it’s name, so snow will likely be light with SLRs of only around 15:1 (relatively crystalline snow). This will all combine to produce only 1–2cm of snow despite the fact that it will snow most of the day. Temperatures will warm up to around –15°C as a little bit of mild air pushes into the province with this system, but temperatures will plummet right back to where we were before as the clouds clear out fairly quickly on Saturday evening and we head to an overnight low of, again, around –28°C.

Sunday


Mix of sun & cloud. Chance of flurries.
-20°C / -28°C

Skies will start off sunny on Sunday but another weak system tracking across southwestern Manitoba will spread some cloud into the Red River Valley midday. This disturbance will track through fairly quickly so we’ll likely see a chance of flurries (with better chances over southwestern Red River Valley) late in the morning into the early afternoon. The clouds will clear out by evening as we head to another cold night with temperatures dropping back to about –28°C. Heading into next week, the flow aloft begins to become significantly more zonal, allowing milder Pacific air to push further eastwards across the Prairies. Temperatures will generally be warmer but by exactly how much is still hard to tell. Ensemble predictions have moved from an above-normal temperature forecast next week into a more seasonal-looking pattern. Either way, we’ll certainly be leaving the temperatures we’ve seen over the past week behind for a while.

  1. It should probably be said that the “normal” temperature for late January in Winnipeg is most likely just an average of the extremes.  ↩

A Little Snow Before The Coldest Weather This Winter

Brad Leave a comment

Two batches of snow followed by the coolest temperatures of the winter are in store for Southern Manitoba over the next few days.

Clipper Snowfall Totals

Forecast snowfall totals from this clipper system across Southern Manitoba.

An Alberta Clipper will begin it’s march across the Prairies today, rapidly moving from Northern Alberta east-southeast into Northern Minnesota by tonight. This system will drag a warm front eastwards across Southern Manitoba, spreading 1–2cm of light snow across the Red River Valley. The snow will ease off this afternoon to just scattered light flurries as the weak leading impulse moves off into NW Ontario.

Temperatures will warm to around –8°C by this afternoon, with the warmer daytime highs near 0°C locked into the extreme SW portion of the province. A second shot of snow will push into the Red River Valley tonight as the main low centre of the Alberta Clipper moves through the region. Temperatures in the RRV will rise to –4 or –5°C by midnight before starting to drop as the cold front moves through. The bulk of the snow will start near midnight and taper off on Saturday morning with a further 3–5cm of snow accumulation for a total of 4–7cm by the time this whole system moves through.

A few flurries will be around on Saturday as Arctic air begins building into Southern Manitoba yet again. Fairly strong northerly winds gusting up to 60–70km/h will develop early Saturday morning which will result in significant blowing snow in the RRV outside the City of Winnipeg. “Ground blizzard” conditions will be relatively widespread, with particularly poor visibilities as low as 100–200m on west-east running roads, such as the Trans-Canada Highway from Winnipeg to Portage La Prairie. Given the already slick conditions of many roads around the province, be sure to give yourself plenty of extra time if you need to travel on Saturday. The winds will lighten up by mid-afternoon, marking the start of our entry into a major deep freeze. Bitterly cold Arctic air will be pushing southwards behind this clipper system, with temperatures falling to around –25°C by the end of the day. Temperatures will plummet tomorrow night, with overnight lows through the Red River Valley dropping to the –30 to –35°C range. Temperatures will rebound slightly on Sunday as a weak disturbance brings some cloud and a chance of a flurry or two, but even colder air looks to be pushing in on Sunday night.

If the models are to be believed (which I do have some hesitation at the moment), temperatures will drop through the day on Monday to nearly –30°C by the end of the day, with overnight lows dipping to nearly –40°C. I think that the models are getting a little too excited about how cold it will get. The GEM-GLB model’s overnight lows have been 5–6°C too cold over the past week, so it’s more likely that we’ll see lows closer to –35°C than –40°C. At that point, though, it’s colds enough that those numbers don’t even matter. It’s certainly going to be an extremely cold start to next week.

Alberta Clipper to Bring More Snow This Week

Brad Leave a comment

An Alberta Clipper will bring more snow to Southern Manitoba this week. The system will also bring moderating temperatures, followed by another arctic blast.

Map of Tuesday's Alberta Clipper System - NAM Model

Before the Clipper arrives on Tuesday, we’ll see cold weather again on Monday. High temperatures on Monday will be in the high minus teens with light winds. A southerly flow will begin to develop over Manitoba on Monday night ahead of the next low pressure system. The south wind will become quite strong during the day on Tuesday, with wind speeds of 30-40km/h gusting to 50-60km/h in most areas (except in the Red River Valley where speeds may be a bit higher than that). These strong south winds will bring in much warmer air, with highs on Tuesday likely to be in the low to mid minus single digits in most areas. The Alberta Clipper is expected to begin spreading snow into Southern Manitoba on Tuesday afternoon. Areas in western Manitoba can generally expect 2-4cm of snow, with lower amounts the further south you go. In eastern Manitoba the highest amounts are expected, with total accumulation of 4 to 8cm expected (with higher amounts the further north you go). In the Red River Valley generally 2-5cm is expected, with Winnipeg and Selkirk having the best chance at higher end amounts. As the clipper moves past on Tuesday night, north-westerly winds will develop. These winds will be fairly strong, with readings of 40km/h gusting to 60km/h expected. This will generate blowing and drifting snow in open areas on Tuesday night. Blizzard conditions are not expected, but poor road conditions are still probable.

Models are suggesting that we may see another weaker Alberta Clipper pass by on Wednesday. At this point it’s too early to say exactly how much snow it will produce, but it has the potential to produce amounts similar to those experienced on Tuesday.

Beyond Wednesday it’s hard to tell what will happen next. It appears that Southern Manitoba will be right near the boundary between very cold arctic air to the north and somewhat milder air to the south. If this boundary ends up a bit further south than expected we’ll be firmly placed in that arctic air mass, but if the boundary is further north than expected we may get into the milder air. More weak Alberta Clipper systems are forecast to ride along this arctic boundary, so our position near it suggests we may see more light snowfall events later this week.