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A Break From The Cold

January 25, 2013April 3, 2015 Brad Leave a comment

A break from the bitter cold snap that we’ve been under the influence of over the past week is on it’s way this weekend.

850mb temperatures on Saturday morning from the GEMGLB model. Near–0°C or above temperatures are forecast to push across Southern Manitoba aloft, bringing much warmer weather to the region.

Behind yesterday’s Alberta clipper system, a zonal flow[1] is pushing into the Prairies and breaking down the entrenched northwesterly flow that has been in place over the past week bringing us multiple nights with overnight lows in the mid-minus 30’s and many daytime highs barely climbing over –25°C. The milder Pacific air contained in the more zonal flow will begin to work it’s way eastwards across Alberta and Saskatchewan today, bringing daytime highs closer to –7 or –8°C instead of –20°C.

Friday

Friday

Sunny
-20°C / -29°C

For us in Winnipeg & across the Red River Valley, we’ll face one more day with quite chilly temperatures. Under mainly sunny skies, temperatures will climb to about –20°C with light winds. Temperatures will drop quite a bit tonight as another arctic ridge passes over us; our last cold night before the warmer air pushes in will see us with temperatures bottoming out near –29°C.

Saturday & Sunday

Saturday

Mix of sun and cloud. Increasing cloudiness overnight.
-12°C / -13°C

We’ll see a mix of sun and cloud on Saturday as the milder Pacific air finally pushes in. Temperatures will climb quite quickly through the late morning and early afternoon from our overnight low all the way up to –12°C by the evening hours. By the evening there may be a few light flurries over the southeast portion of the Province (Whiteshell & Sprague), but through the Red River Valley there’s no significant chance of any snow. Temperatures will remain fairly steady overnight as more clouds push in.

Sunday

Mainly cloudy. Chance of flurries overnight.
-7°C / -8°C

We’ll see mainly cloudy skies on Sunday as more moisture and lift begin to spread over the province ahead of an approaching shortwave. Temperatures will climb to around –7 or –6°C across Southern Manitoba; the warmest day we’ve had in what seems like quite a long time. Overnight, an increasing chance for light snow will move into the province, starting with southwest Manitoba in the evening hours and slowly spreading eastwards overnight. Temperatures will remain steady, perhaps drop a degree or two, overnight as we remain cloudy with warm air over the region.

Next Week

Next week is looking like we’ll see a return to colder weather. There’s some uncertainty with regards to the strength of Monday’s system; it may be a fairly organized feature that brings close to 10cm over SW portions of the province and 5–10cm over the Red River Valley and areas eastwards, or it may end up being a rather disorganized system that brings just some scattered light flurry activity with only a couple cm for most places. With either scenario, it still looks like Monday will be the warmest day yet in our little break from the cold. Unfortunately, it looks that once this system passes, Arctic air will once again push back over the Eastern Prairies and establish itself; locking us back into a sunny, but very cold, weather pattern with daytime highs back near –20°C.

A zonal flow, with respect to meteorology, is one that travels more west-east than it does north-south. By contrast, a meridional flow is one that has a larger north-south component than west-east. ↩

Bitter Cold Continues

January 23, 2013April 3, 2015 Brad Leave a comment

The bitter cold entrenched over Southern Manitoba will persist a few more days as another Arctic Ridge slides through the province.

850mb temperatures valid this morning from the GEM-REG. A pool of bitterly cold Arctic air over the province will restrict daytime highs to the mid-minus-twenties today.

We’ll see an extremely cold day today with plenty of sunshine and a high only around –25°C. This is some 12–13°C below our normal daytime high for this time of year of –12°C. Temperatures will drop below –30°C tonight for a 3rd night in a row.

Light Snow on Thursday

Temperatures will continue to be cold on Thursday with a high near –21°C as a weak disturbance slides across the province in the northwesterly flow aloft. This will spread an area of snow across southwestern portions of the province early in the morning and into the Red River Valley near midday. With temperatures so low SLR values will likely be quite high, somewhere in the range of 20:1 to 25:1. This very high “fluffy factor” will help produce snowfall accumulations of 2–4cm by Thursday evening. Temperatures will climb to around –20°C on Thursday, aided by the cloud cover that will push in.

On Friday sunshine will return as we face another cold day with highs below –20°C. Fortunately, it appears that warmer air will finally be pushing into the region by Friday night. Temperatures look to drop only a few degrees from our daytime high as we then see much warmer weather on Saturday and Sunday as highs climb back towards the –12 or –13°C mark. It looks like we’ll see a mix of sun and cloud through the weekend, with a chance for another couple of cm of snow on Sunday.

An Arctic Blast

January 21, 2013April 3, 2015 Brad Leave a comment

This week will feature the coldest weather so far this winter, which is probably about all you need to know.

850mb temperatures on Monday morning

As we come off Monday morning’s very cold low temperatures, daytime highs won’t be able to get very warm, with values in the mid minus twenties expected. When you factor in the wind chill it will feel more like the low minus forties on Monday morning and the mid minus thirties on Monday afternoon. As we move into Monday night temperatures are expected to plummet once again. Models have had significant difficulties figuring out what will happen by Tuesday morning. Models have shown lows as cold as -47C on Tuesday morning (obviously an erroneous value), or as warm as -28C. It seems probable that we’ll end up somewhere between those two extremes, with lows in the mid minus thirties most likely. It shouldn’t be very windy at all on Tuesday morning, so at least we won’t have a big wind chill to contend with as well. It looks like we’ll “warm” up a bit on Tuesday, with daytime highs in the low minus twenties expected.

We shouldn’t see extreme overnight lows again on Wednesday morning since a weak passing weather system will prevent temperatures from bottoming out. However, another arctic front is forecast to pass through Southern Manitoba during the day on Wednesday, setting up more very cold weather for late week.

Unfortunately, there are no indications to suggest that we’ll see a warm-up any time soon. That means we may be stuck with cold to very cold weather for the rest of January.

A Little Snow Before The Coldest Weather This Winter

January 18, 2013April 3, 2015 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.

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.

A Weather Moment

Author: Brad