Cold.. and staying cold..

The weather looks cold for the next couple of weeks at least as a large Arctic airmass spreads over the Prairies. For this week, the cold weather will be briefly moderated somewhat by occasional weak Alberta clipper systems tracking across the southern Prairies from the west. Across southern MB, one of these clipper systems is forecast to track through on Wednesday followed by another one on Friday. Each of these systems will spread cloud and some snow to southern MB bringing about 2-5 cm with each system. Still, these minor amounts in combination with the cold temperatures will make for icy road conditions through the upcoming week. Behind these systems will be a reinforcement of Arctic air into southern MB, especially over the weekend into next week with daily highs in the minus 20s and lows in the minus 30s.

You think it's cold now.. wait til next week!

Get the cold weather gear and block heater ready.. the coldest weather of the season so far is poised to spread over the Prairies next week with temperatures likely in the minus 20s and minus 30s. We'll get a sneak preview of this cold airmass over the weekend as an Arctic high drops in from the north, giving us highs only in the minus 15 range and lows near minus 25 Saturday night. On Sunday into Sunday night, an Alberta clipper is forecast to spread cloud and snow across southern MB with 2-5 cm possible. In behind this clipper will be a major push of Arctic air as a massive Yukon ridge drives very cold air across the Prairies. This cold air will spread into southern MB on Monday with gusty northerly winds, and temperatures around minus 20, giving windchills of minus 30 to minus 35. Very cold conditions are expected the rest of the week as the Arctic airmass builds in..possibly modified briefly midweek as a weak clipper system scoots by. Look for daily highs next week in the minus 18 to minus 23 range, and lows in the minus 28 to minus 33 range.

EC releases winter outlook for 2008/09

EC has issued its winter outlook for the upcoming 3 month period of December through February. The outlook, produced from a consensus of 4 climate models ingesting 3 weeks of current weather conditions and extrapolating into the future, indicates warmer than normal conditions this winter over the East Coast (mainly Newfoundland and Nova Scotia) while colder than normal conditions are forecast from northern Quebec through Hudson Bay and northern MB into NWT and the Yukon. Over southern MB, there are equal chances of a "normal" or below normal winter with a lower probability of a mild winter. Across the rest of the country, model consensus does not point to any specific outcome, with generally equal chances of above, near or below normal conditions (i.e. a non-forecast)

EC's 3 month outlook is available on EC's Weatheroffice website at this site. NOTE: For monthly and seasonal outlooks, I highly recommend you look at the probabilistic outlook map rather than the deterministic outlook map. The deterministic maps do not accurately reflect the true output of the climate models, which is better reflected by the more informative probabilistic maps. The probabilistic maps more accurately indicate where the climate models are showing the best agreement for above or below normal conditions occurring, and where there is the most disagreement. This measure of uncertainty is not indicated on the deterministic maps which make them subject to greater misinterpretation.

Alberta clipper system approaching MB

A strong Alberta clipper system is moving across northern SK today ushering in a gusty southwest flow of very mild Pacific air over southern AB and southern SK. Temperatures have soared into the mid teens over southern AB with several record highs established for December 1st.  This warm airmass will be moving towards southern MB over the next 24 hours, but the bulk of the mild air will be bypassing to the south of Winnipeg into the Dakotas overnight. Even so, gusty south winds tonight of 40-60 km/h will bring rising temperatures overnight to the Red River valley, with temperatures expected to climb towards the freezing mark by daybreak. In fact, there's a chance we may get above zero (+1 to +3C) for a brief period early Tuesday morning as our winds shift into the west and tap some of the retreating mild airmass over southern SK. Regardless, the mild temperatures will be short lived as strong northwest winds develop behind the clipper system Tuesday, and bring increasingly colder air through the day. So watch for temperatures to fall Tuesday, especially in the afternoon and evening as those northwest winds pick up. 

As for precipitation with this system,  it looks like Winnipeg may get a period of snow tonight with a risk of freezing rain or ice pellets overnight as the warm front approaches. The bulk of the snow should remain north of Winnipeg through the Interlake and central MB, but we could see a couple of cm tonight. If any freezing precipitation develops, the best chance will be between 10 pm and 4 am, but amounts should be light. Nonetheless, road conditions could be on the slick side Tuesday morning as this system moves through with some mixed precipitation and near freezing temperatures. Look for windy and colder conditions by Tuesday afternoon with occasional flurries giving a dusting to 2 cm over Winnipeg and the Red River valley.                   

   

November 2008 Highlights

November 2008 finished milder than normal in Winnipeg and Southern MB, the 4th month in a row with above normal temperatures. Precipitation for the month was also above normal, but that was largely due to a storm system on the 6-7th that brought large amounts of rain, freezing rain, ice pellets and snow to the Red River valley. The last 3 weeks of the month were quiet and inactive, with little in the way of significant precipitation or large temperature swings. As a result, the month seemed to delay winter after a somewhat early start.

Overall, the month finished over a degree above normal with a mean temperature of -4.2C at the airport (-3.2C at my site) vs a long term November average of -5.3C. The month began on a very mild note, with a record high of 18.8C on the 3rd.. the warmest November day in Winnipeg since Nov 5th 1975 when we hit 23.9C (all time November high). The mild start and snowfree ground had golfers enjoying some late season golf through Nov 4th, with no hint of winter like weather. That would change soon enough however as a storm system tracking through from the Dakotas on Nov 6th-7th brought a messy mix of rain, freezing rain, ice pellets and snow to the Red River valley. The storm brought some 40-70 mm of rain and ice pellets to the southern Red River valley bringing high water levels to the Red River on the heels of a wetter than normal fall. By the morning of the 7th, Winnipeg and much of the western Red River valley had been transformed into a winter wonderland, with about 5-8 cm of snow falling in Winnipeg and heavier amounts of 15-25 cm west of the city from Pilot Mound through Portage. Snow has remained on the ground since with a month end snowcover of 5 cm in Winnipeg. Areas further south and east of Winnipeg however saw much less snow with this storm system, and enjoyed snowfree grounds through the end of the month.

After the 7th, the weather turned quiet and uneventful with some minor snowfalls now and then but little in the way of high impact weather. A mid month cold snap brought the month's coldest temperature of -19C on the 21st but that was followed by mild and dry conditions to end the month. The month finished with about 15 cm of snow at my site, slightly less than an average November monthly snowfall of 21 cm.

Overall, an early tease of winter, but a mild and quiet month overall.