Wednesday, December 02, 2009

Cold winds and open lakes = snowsqualls for some tonight through Friday

Colder weather is finally moving over southern Manitoba, ushered in by brisk northerly winds advecting colder Arctic air into the province for the first time in weeks. These winds are blowing over the still open waters of the Manitoba lakes, where ice formation has been delayed this year due to the prolonged mild weather in November. The result will be localized bands of lake effect snow off Lake Manitoba and Lake Winnipeg (particularly off the north basin). Northerly winds tonight and Thursday will set up snow bands immediately to the south of the lakes affecting areas through the central Interlake, as well as the Portage La Prairie and Beausejour areas. By Friday, the winds should veer slightly to the north-northwest which would push the snowbands a little further to the east. 10-20 cm of snow is possible under persistent snow bands while little snow is likely outside these areas. The cold weather is expected to persist for the next week or two, which will quickly freeze up the lakes over the next couple of weeks shutting down the lake effect machine.

UPDATE: see local radar image above from Thursday morning showing lake effect bands

13 comments:

  1. could winnipeg be affected by one of these snowsqualls?

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  2. Typically Winnipeg lies in between lake effect snowbands, as we need a 300 degree wind off Lake Manitoba or a 020 degree wind off Lake Winnipeg to get lake effect snow. Tonight into Thursday low level winds are expected to be straight northerly (350-360 degrees) veering to 330 by Friday. This would tend to put any lake effect snowbands mainly west and northeast of the city. Right now Winnipeg seems to be getting a general area of light snow that is probably enhanced by some lake input, but I suspect that we'll start to see more distinct bands of lake effect developing tonight into Thursday as winds become better aligned in the low levels.

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  3. Rob when you say " but I suspect that we'll start to see more distinct bands of lake effect developing tonight into Thursday as winds become better aligned in the low levels" are you saying that those bands will allign more with Winnipeg or that the bands will be more noticable but missing Winnipeg. Do you think that we will be getting that 2-4cm or is that only if the winds allign themselves to 300. One last question this snow this afternoon just seems to be appearing out of nowhere do you think this will move on or is it just going to sit there for the evening? Thanks

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  4. The bands should become more distinct and narrower off the lakes, but missing Winnipeg. As for the snow now, it appears to be associated with an upper trough over SE MB that will drift into NW Ontario tonight. So this snow will likely lighten up through the evening into tonight transitioning to more discrete lake effect snow bands off the lakes.

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  5. I can't beleive how cold of an aimass that will be hitting us early next week!!!

    What a dramatic change from November!!!!

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  6. I was traveling yesterday and came back to Winnipeg today!!!

    I can say that just to the west they have a lot more snow than Winnipeg!!!

    Portage La Prairie even has 4 inches of snow on the ground!!!

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  7. Yep.. similar amounts of 5-10 cm reported just northeast of Winnipeg through East Selkirk and Tyndall areas.. Winnipeg dodges the bullet again. Just a trace of snow here.

    Lake effect snowbands are weakening now as some warmer air aloft moves in today. A general area of light snow through the Interlake is moving south and may give Winnipeg a cm or two of snow this afternoon.

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  8. With these current tempertures how long will it take for those lake to freeze up and cap them? Looking at the weekend its going to be pretty cool so I would think only a few more days.

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  9. I'm always amazed how quickly these big lakes can freeze up given sustained cold weather. Ice forms on the edges and in the narrows first, then gradually fills in to cover the whole lake. If the weather is cold enough, this can sometimes take only a few days at this time of year. Given the expected temperatures for the next week, I'd expect the lakes to freeze over by the end of next week or so.

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  10. Amazing! 10 to 15 feet of ice on west shore of the Red River opposite St Vital Park (Pony Corral to Bishop Grandin Bridge). No ice this time yesterday.

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  11. Robs-Obs Webcam Page Link the North Kildonan Web cam shows ice along the shore under the Kildonan Bridge.

    http://members.shaw.ca/wpgwx/robsobs/ywgcams.htm

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  12. Rob do you agree with those temperatures for early next week for southern Manitoba????

    Do you think Environment Canada has gone cold enough????

    I think some of those overnight lows could be very cold with a clear night and light winds!!!

    Good to see Winnipeg has been getting this light snow the past couple of days to make the ground white!!! I was wondering if we were the only ones that would have no snow on the ground!

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