Sunday, November 29, 2009

Alberta clipper threatens snow for Tuesday

An Alberta clipper storm system is forecast to track across southern MB Tuesday, bringing the potential of the season's first significant snowfall over portions of southern MB. The center of the storm is expected to move across the Riding Mtn area early Tuesday tracking through the northern Red River valley and into the Whiteshell by Tuesday evening. The heaviest swath of snow is expected along and north of this storm track.. putting the most significant snow along and north of the TransCanada where 10-15 cm is possible. Snowfall amounts will drop off sharply south of this track with 5 cm or less likely. Gusty northwest winds will follow in behind the system bringing a drop in temperatures by Tuesday evening, as well as areas of blowing and drifting snow in open areas. Snowfall amounts will depend critically on the exact path of this system, so stay tuned on the progress of this potentially first wintery blast of the 2009-10 winter season.

UPDATE: Latest model guidance has shifted the track of Tuesday's system further south. As a result, the heaviest snow is now expected to fall over southwest Manitoba and over the southern Red River valley into SE Manitoba where 10-15 cm is possible. Winnipeg is expected to lie on the northern edge of the heaviest snow.. with 5 cm possible. Note that Winnipeg may get heavier amounts of snow if this system tracks a little further north than latest projections. Stay tuned..

16 comments:

  1. It seems all the models (except the GFS) are starting to shift the heavy snow a little south!!!!


    Also winds could be quite strong
    40 -60 km/h look likely!!!

    I see environment Canada is now calling for 2- 4 cm of snow for Monday night plus whatever we get on Tuesday!!!

    Finally ......Winter.....

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  2. In an interesting twist, the 00Z NAM has shifted the main swath of snowfall towards areas along the border. Don't tell me a system is shifting south of the border AGAIN!

    Before I get too excitied, I would like to see the 00Z GFS.

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  3. Gem has a similar solution to the NAM, while the latest GFS has also shifted further south. Most models now carry the storm track from SW MB into northern Minnesota, with the bulk of the snow falling over southwest MB and along the US border. Quite the change in opinion from this morning.. we'll have to see if there's any consistency with the next run. But now it looks like Winnipeg may be on he NORTHERN edge of the heaviest snow instead of south of it!

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  4. Yeah From 00z sunday runs to 00z mondays run quite the difference with a consensus track of the sfc low into northeast nd and nrn mn and thus the hvy snow band a bit farther south more into far ne nd and nrn mn.

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  5. I saw latest Winnipeg fcsts...10-15 cm for southwest Manitoba (Brandon to Killarney) then 10 cm Morris and Emerson to 5 cm Winnipeg to Sprague (or least that is what I infer). I went about 4-6 inches of snow into far ne ND and far NW MN good frontogenesis and deep vertical motion per gfs time height cross sections this morning. Yes I am working the mids. good luck... we will see...

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  6. The 06Z run shifts the track slightly further north again...right through Steinbach!

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  7. Rob!

    Snowfall warning issued for south western Manitoba but nothing for the south east!

    The only thing is that the National weather Service has a winter storm watch for area along the border of south east Manitoba

    While Environment Canada has nothing along the same area of the border!

    What are your thoughts on this ????

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  8. GEM is suggesting heaviest snow will be over SE SK and SW MB overnight into Tuesday morning, with slightly less amounts over SE MB. Snowfall warning is out for area with highest confidence that warning thresholds will be met (10 cm in 12 hours or 15 cm in 24 hrs) Current projections hint that SE MB may be just shy of warning amounts.. but it'll be close. We'll see if they extend the warning eastward into the southern RRV and SE MB in the afternoon update.

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  9. The first week of December looks to be so much colder than what we have been used to !!

    Spoiled so much in November that this is gonna be a rude wake up call!!!

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  10. The 18Z NAM has the main precip shield angled NW-SE. This allows it to miss SE MB completely and only hit SW MB. On the other hand, the 12Z GFS has the precip shield angled W-E, which spreads snow across most of southern Manitoba. I think the NAM solution will be right in this case, but you never know.

    On a side note it is amazing how this system has shifted...from the northern Interlake, to the southern Interlake, to Winnipeg, then to the border, then back up to Steinbach, then all the way into the south-west corner only.

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  11. I think I probably jinxed us to miss out on the snow. Spent the last 2 days getting all the equipment turned over to snow. Probably first time ever we're actully almost ready for it to snow. Usually we're still switching the machines over to snow as they go out to clear.

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  12. Is winnipeg getting anything out of this system ? I mean TWN said yesterday that we will get only 5 CM, Today there saying only 3 CM. I was really hoping for at least 10!.

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  13. Well as of 4:00pm EC bumped their snow amount from 2cm to 5cm.

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  14. Latest GEM and NAM put heaviest axis of snow over SW Manitoba and far northern ND and MN along and south of the international border. Winnipeg looks to escape this thing with nothing more than a dusting if anything.

    Vsbys down to 3/4 mile in snow in Regina this evening with snow now spreading over SW Manitoba.

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  15. Looking at Weather Nets radar forecaster it appears to show the snow event a miss for Winnipeg

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  16. The 00Z GFS hangs tough with its more northerly solution. Frankly, I haven't been very impressed with how the NAM has handled this Clipper. It changes its track ever 6 hours, and still doesn't seem very accurate. I chose to go with the GFS because it has been fairly consistent. This model gives Winnipeg 4 to 8cm and Steinbach 5 to 10cm. Areas in SW MB and along the border get 10 to 15cm.

    Although I'll probably be wrong in the end, I don't think the NAM should win this battle...it isn't hard to forecast a system if you can change your mind 4 times a day!

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