Sunday, December 01, 2013

Winter storm gaining strength over western Canada.. impacts to spread over southern Manitoba Monday through Wednesday..

Winter storm and blizzard warnings
cover much of western Canada
Sunday evening
A major winter storm is gaining strength over the Canadian Rockies this evening.. and this storm will be spreading its wintery impacts across the southern Prairies into southern Manitoba over the next few days. Winter storm and blizzard warnings are out for much of Alberta and southern Saskatchewan as the storm intensifies tonight into Monday bringing snow, increasing northerly winds and falling temperatures across the western Prairies. The first wave of snow from this system is expected to spread over southern Manitoba Monday with a few cm possible especially over SW Manitoba where 5-10 cm is possible.  The storm is forecast to track across Montana and through the Dakotas spreading another wave of snow across southern Manitoba Monday night through Tuesday into Wednesday. There remains considerable uncertainty as to how intense this storm system will be by the time it reaches southern Manitoba by Tuesday. Some models are suggesting the storm will re-intensify over the Dakotas bringing significant snow and possible blizzard conditions to southern MB and the Red River valley Tuesday into Wednesday. Other guidance shows the storm tracking mainly south of the border with minimal impact over Winnipeg and the northern Red River valley. At this point, it's best to be prepared for a possible significant snowfall event Tuesday into Wednesday across southern MB, especially over SW Manitoba and the southern Red River valley with areas of blowing and drifting snow increasing by Wednesday. More details will become clearer as the storm evolves over the next 24 hours. Note that winter storm watches are now in effect across all of North Dakota and northern Minnesota in advance of this system, so be prepared for adverse winter weather if you have any travel plans to the west and south of Winnipeg over the next couple of days.

Keep track of weather conditions across southern Prairies and North Dakota via webcams from Rob's Obs webcam page.  

28 comments:

  1. Well, interestingly NAM is the only model that has been consistent so far. I for one hope for some sort of storm because it's just been too long since we've had any storm of interest in what feels like many years.

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  2. I see some snow to the southwest of Winnipeg, on radar. Could that give us some accumulation tonight??

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  3. The latest NAM run is still persistent in giving southern Manitoba a big dump of snow. I'm not going to vote on the snow poll just yet....

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  4. .. and the latest RGEM is still saying main action will be bypassing Winnipeg to the south. Two opposing views with no signs of compromise! (are these weather models, or politicians? :) Amazing how these wildly opposing model solutions are maintaining their opinion even at this late stage.

    Great response to the snow poll with over 40 votes cast already. Leading pick is 5-10 cm, but all picks between 2-25 cm are in the running which illustrates the degree of uncertainty still out there.

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  5. The question now is: who's the outlier? Now NAM has a partner when it comes to giving us a big dump of snow and blizzard conditions. And that partner is GFS

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  6. Rob, that snow that we are expecting today, is that already part of the system that we have the snow poll for?? I know that the snow poll says Tuesday's system, but the overnight snow will NOT count ??

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  7. Still don't see why we would get hit by this big storm. They never hit us. Hopefully I'm wrong and all models make a drastic turnaround at very last minute because I want a big storm too, but we have to remember big storms are so very rare here.

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  8. Initial wave of snow spreading across SW MB and ND this morning with very little movement into Winnipeg/RRV.. so I don't expect much for Winnipeg today. The 2-4 cm for today and another 2-4 cm tonight seem overdone for Winnipeg, with likely only a dusting to 2 cm from this first wave for us. Better chance of 4-8 cm over SW MB and southern RRV.

    NAM has backed off considerably on snow amounts Tuesday for Winnipeg with bulk of snow spreading across ND, before nailing us Wednesday with 15 cm of snow and strong winds. NAM is still the only model showing this, as all other guidance are further south on the storm with minimal amounts over Winnipeg through Wednesday. As it stands now, here are the latest snowfall projections from the various models for Winnipeg Tue-Wed (assuming 10:1 snow ratio)

    NAM ...... 16 cm
    NAEFS .... 6 cm (ensemble)
    ECMWF ..... 5 cm
    GFS ...... 5 cm
    GGEM ..... 2 cm

    I will update this list with 12Z runs this morning.

    Almost 60 responses to my snow poll! Leading pick is 10-15 cm with 5-10 cm close behind. Keep those guesses coming!

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  9. I can't remember the last time all the models actually consistently agreed on something around here. Seems whenever a storm is approaching we seem to lie in the land of model uncertainty, with its usual teases and then backs off last minuet.

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  10. 12Z NAM finally starting to cave.. showing only 4 cm now for Winnipeg Tue-Wed, more to the south.

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  11. EC just updated their forecast for Winnipeg. They are yanking out the 2-4 cm of snow and now only 30 percent chance of flurries..

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  12. This is actually quite depressing. Get your hopes up for a great winter storm and then get 4 cm. We always get these boring little dustings. Just enough to shovel but never enough to have to use snow blowers. When will we ever get a good 30 cm snow storm?

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  13. Rob, could you please explain why weather models have such a tough time with precipitation events 3 days out, while they seem to have a very easy time predicting an airmass almost a week in advance....??

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  14. Lol this just keeps getting better and better. Its like the models are realizing closer to the date of the event that their in Winnipeg and saying Oh hey wait a minute this is Winnipeg. Abort!!

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  15. Summer, winter just can't catch a break. Whether is that awesome thunderstorm that just misses us or that sweet winter storm that goes around us, this seems to be an area where extreme weather hates us. We'll get teased at first with the possibility of something, raising hopes only to be dashed to pieces 1-2 days out when it really matters. And then its at least another month or more when just the possibility will come back and then the same thing happens. At least in other places if you miss something, wait just another week and you'll get something. Here its a month or more. So depressing

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  16. >> Anonymous said... Rob, could you please explain why weather models have such a tough time with precipitation events 3 days out, while they seem to have a very easy time predicting an airmass almost a week in advance....??

    Anonymous.. it's a question of scale. Airmasses are hundreds to thousands of miles in size, while precipitation shields associated with storm systems are tens to a few hundred km in size. Quite simply, it's easier to forecast a large scale airmass than a smaller scale storm system.. and there's a limit to the predictability based on the event scale. The smaller the scale, the shorter the time period you can predict it accurately. And also note that being off 1 or 2 hundred km with an airmass won't make much of a difference in the overall pattern, but being off a couple hundred km with a storm system can mean the difference between getting a major storm and getting nothing.

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  17. On a side note, 0.2 km visibility in Calgary right now. Now that's a bizzard ;)

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  18. >> Jeff said... This is actually quite depressing. Get your hopes up for a great winter storm and then get 4 cm. We always get these boring little dustings. Just enough to shovel but never enough to have to use snow blowers. When will we ever get a good 30 cm snow storm?

    Yeah, looks like storm lovers will be disappointed with this one, but in reality.. really big storm systems that dump 30 cm or more are not that common in Winnipeg, or throughout the RRV. If you look at memorable historic blizzards which dumped 30 cm or more over the city, only a few stand out.. the blizzard of March 1935, blizzard of March 1966, the blizzard of Nov 1986, and the April 1997 blizzard (could be a couple more but none stand out off the top of my head). So only 4 or 5 really memorable ones in the past 80-100 years.. on the order of 1 in 20-25 years or so. In between we get smaller but still fairly intense winter storms more frequently (such as last year's Nov 10 storm). So although people think we miss out every year, in reality.. getting the "big one" is still a fairly rare event for us.

    But always remember, it still can happen any winter. And we still have a lot of winter left.

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  19. Rob, do you think we still have a chance at 5 perhaps even 10 CM tommorrow?

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  20. >> Anonymous said...Rob, do you think we still have a chance at 5 perhaps even 10 CM tommorrow?

    It's looking less and less likely. I'm thinking 2-5 cm for Winnipeg, mainly Tuesday night into Wednesday. Guidance is coming more in line that storm will track more to the south and Winnipeg will miss out on the heavier snow. There's an outside chance we may get 5-10 cm Tuesday night as storm intensifies to our southeast and swings some snow back over us, but right now, looks like bulk of it will stay to our south.

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  21. Rob, do you think there's a good likelyhood that we will stay well below normal through the entire month of December?

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  22. Rob, do you think that Winnipeg will see it's first -30 of season this weekend, or do you think that is a longshot??

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  23. Seems to me we've heard this before with a forecast of only 2-5 CM and have received more than that each time in the last couple of weeks. Last Wednesday being a prime example of that. We pretty much have more snow on the ground that what had been forecasted so I wouldn't rule out any surprises.

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  24. The funny thing is that the blizzard of Nov. 1986 was not anticipated to be as significant as it was but element of surprise kicked in and storm tracked further north than anticipated and we got hammered as a result. I remember that event very well. And then there's the end of December 2006 as another example where only a small forecasted snow event turned into a 30+CM event as once again we got surprised by that one.
    So although big storms are not common here we have been known to be surprised by some bigger snow events than forecasted.

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  25. For me personally, I am happy to here that this is not likely going to be a big event for us. For storm lovers it's a disappointment but for me the less snow we have the better as far as i'm concerned. I just hope we don't get surprised this time.

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  26. Meanwhile, Alberta has just been getting pummelled with storm after storm since October. You usually think Alberta is drier than southern Manitoba, but for quite a while now that has not been the case.

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  27. Latest snow projections for Winnipeg from Tuesday through Wednesday from the various models.. pretty much everyone agreeing now main action will miss us to the south. Assuming 10:1 snow:water ratios.. but with cold temps, snow amounts could be 50% higher than these numbers suggest.

    NAM ..... 7 cm
    NAEFS ... 6 cm (ensemble)
    GFS ..... 4 cm
    ECMWF .... 3 cm
    RGEM ..... 2 cm
    GGEM ..... 1 cm

    So generally about 5 cm expected Tuesday through Wednesday.. maybe up to 10 cm, with higher amounts as you go towards the US border. Highest amounts of 15-25 cm expected across portions of ND and northern MN..

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  28. I am very curious to see the updates tomorrow morning, the level.of certainty will for sure be higher! #jack

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