Friday, November 29, 2013

Tranquil weather over the weekend.. then major storm possible over southern MB by middle of next week followed by Arctic blast..

ECMWF model valid 6 am Thu Dec 5
showing possible major storm
impacting southern Prairies
The weather over southern MB will be generally tranquil for the next few days with no major systems expected to impact the area. Generally cloudy skies and seasonable temperatures are forecast over the weekend before an increasing chance of some snow by next Monday and Tuesday as a storm system tracks through southern AB into southern SK. Things may get a lot more interesting by next Wednesday into Thursday as long range models are indicating the potential of a powerful Colorado low system impacting southern MB and southern SK. It is much too early to be more specific on who will bear the brunt of this storm, if it all, but at this point, it's prudent to be aware that there is the potential for a major storm system to affect parts of southern MB and southern SK by the middle of next week. One thing that looks more certain is the change to much colder weather in the wake of this system later in the week through next weekend, with highs in the minus 20s and low in the minus 30s possible along with colder wind chill values. Get ready folks.. a blast of Arctic weather is on the way next week!          

29 comments:

  1. Is there a reason why the Decembers of late (2008, 2009, 2012, and now 2013 as predicted by Accuweather) have been trending colder than normal in this part of the continent?

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  2. Major discrepancy right now between Canadian GLB model and the GFS and ECMWF on this potential storm over us next week.

    Canadian GLB is more aggressive on clipper that will be impacting southern AB and southern SK Sunday into Monday, with snow from that system spreading into southern MB Monday into Tuesday. It then takes low across central US plains and into Ohio Valley by Wed/Thu with snow well to the south and east of southern MB.

    GFS and Euro on the other hand keep bulk of snow with that AB clipper over western Prairies into Montana, then develop strong low over southern MB by Wednesday as impulse from Colorado merges with clipper from SK. Will be interesting to see how models trend on this one, but for the time being.. that will explain discrepancies in next week's forecasts from the various agencies and media depending on which model they are using. Regardless of who's right.. looks like snow chances will be increasing over us next week, followed by some nasty cold.

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  3. We certainly are due for a big storm. Can't even remember the last time we've had a significant winter storm (maybe December 30-31, 2006). We've had some good ones since then, but none that are really that memorable.

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  4. Holy cow! The GEM model has a low of -39.1 next friday night! That might well brake a record!

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  5. New GFS guidance this evening trending more towards Canadian GGEM solution with stronger AB clipper tracking through Montana and North Dakota Monday into northern Minnesota Tuesday. This impulse is forecast to be our main snowmaker later Monday into Tuesday, instead of a full blown Colorado low Wed-Thu. Still need some more model runs to see if there's more consensus on this scenario, so stay tuned.

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  6. The weather Network is calling for a high of -27 and low of -39 next Saturday. It is so cold that the temperature graph goes to the bottom edge of my screen on my TV...LOL. That cold seems unlikely but it gives you a indication how brutal this airmass is going to be later next week.

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  7. Winter storm watches and warnings out for a large part of Alberta as storm system intensifies across western Canada Sunday. This system tracks into Montana Monday spreading snow into southern SK and SW Manitoba. Things get more uncertain after that as models continue to have difficulty resolving what happens to this system as it tracks over Dakotas Tuesday into Wednesday, which impacts forecast for Winnipeg/RRV. Some guidance (like latest GGEM now) suggest this system will continue to track across the northern/central plains with energy shifting to the south as upper trof digs over SW US. This brings less snow and wind across Winnipeg/RRV Tuesday into Wednesday, although we should see accumulating snow.. perhaps 5-10 cm. In contrast, ECWMF and latest GFS indicate Montana system will track across ND and intensify Tuesday into Wednesday bringing more snow (perhaps 15+ cm) and stronger winds to southern MB including Winnipeg/RRV with blowing and drifting snow issues.

    GFS and GGEM have been flip flopping on which scenario will develop, while ECMWF has been more consistent on stronger low solution. Bottom line.. still too early to say how this system will impact Winnipeg/RRV.. but looks like increasing chances for snow by Tuesday/Wednesday, followed by cold outbreak. Stay tuned..

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  8. It seems the term "flurries" is over-used. To me it suggests minimal accumulation, yet TWN has POP 40% flurries for Wednesday, with 5-10cm accumulation. EC and CBC MB also say flurries for mid next week. People may be in for a surprise.

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  9. Anonymous.. I totally agree. The term "flurries" underplays snowfall potential with a synoptic system. EC forecasts (Day 3 and beyond) automatically default to flurries when a POP is mentioned (e.g 30%, 60%, etc) no matter how intense the system. Another example of how better programming/algorithms are required if you're going to automate the forecast.

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  10. Rob, is there potential for significant blizzard conditions with that system next week?

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  11. Anonymous... If the European model verifies, I would say that yes, blizzard conditions are likely across southern MB by Wednesday, especially the RRV. But there's so much uncertainty on the evolution of this system, that I would put the risk of blizzard conditions at about 30% right now

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  12. We should keep in mind though that the ECMWF is the same model that predicted (with relative accuracy) the path of Sandy last year from a good few days out.

    Definitely a system worth watching.

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  13. Flip-flop. Now the Euro has only a few cm of snow for mid next week. Meanwhile the GEM-GLB has about 25 cm. The Ensemble is all over the place.

    Either way, it's going to turn cold later next week.

    -Garth

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  14. Tonight's models coming more in line that the main energy with this week's storm will be tracking mainly to the south of Winnipeg/RRV Tuesday into Wednesday with main swath of heaviest snow from southern SK through ND into Minnesota. NAM is further north however and spreads significant snow (10-20 cm) across southern MB Tuesday including Winnipeg. NAM however is the odd man out on this solution and doesn't appear likely .. although as we've seen before, even the outliers can be right sometimes. At this point however, consensus appears to be building that worst of this system will be impacting areas mainly west, south and southeast of Winnipeg although we should see some snow out of it. Stay tuned as models are still trying to sort this complex system out..

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  15. Wouldn't be much of a surprise if we missed out. Big storms love to miss the Winnipeg area and has been the tradition for years now. Don't see why that would end now.

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  16. That "sunny" forecast for Tuesday for Winnipeg is wildly optimistic given that NAM, Euro, and ensembles bring about 5-10 cm of snow over Winnipeg Tuesday into Tuesday night. We'll see what today's runs say, but don't be surprised to see that Tuesday forecast change considerably from the current outlook (the drawbacks of automating the forecast based on a single model solution)

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  17. We always loose out to North Dakota/Minnesota!! Doesn't seem to matter what type of storm! Why?? I've lost absolutely all hope that we'll ever get anything! These darn models always tease us at first then just do their usual hum and haw and then track things away from us overall! Can't escape it even in winter! Winnipeg truly is a storm lovers worst nightmare. At least other places not too far away it seems if you miss this storm, you know you'll probably get one in a week or two. Here if you miss one you gotta wait another month or more to even see a potential. Bigger storms you have to wait years! I know you can't control weather but its not fair! >:(

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  18. Rob What do you predict the total snowfall for the Brandon region will be the forecast keeps changing from lots of snow to no snow?

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  19. >> Anonymous said... We always loose out to North Dakota/Minnesota!! Doesn't seem to matter what type of storm! Why?? I've lost absolutely all hope that we'll ever get anything!

    Anonymous.. things still aren't clear on how this system will impact Winnipeg. NAM continues to indicate heavier snow across southern MB including Winnipeg, while everyone else is further south. I think NAM is too aggressive, but there's still a chance it may work out. Hope is still not lost if you're wanting some snow! :)

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  20. >> Anonymous said...Rob What do you predict the total snowfall for the Brandon region will be the forecast keeps changing from lots of snow to no snow?

    I doubt Brandon will see no snow.. looks like first wave of snow moves in Monday, with another wave Tuesday into Wednesday. Still tough to say how much, perhaps 5-10 cm first wave, and another 5-15 cm second wave as a first guess. Looks like a prolonged event in any case Monday through Wednesday.

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  21. Time for a snow poll! How much snowfall will Winnipeg get Tuesday through Wednesday? Vote on Rob's Obs blog poll!

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  22. Winter storm watch has been issued across much of southern Saskatchewan for possible freezing rain tonight then snow and blowing snow Monday into Tuesday.

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  23. Rob, Will Winnipeg see any snow tomorrow wether or not we see any accumulation?

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  24. Model snowfall estimates for Winnipeg Tue-Wed as they stand right now.. (assuming 10:1 snow:liquid ratios)

    NAM ...... 30 cm
    ECMWF .... 15 cm
    NAEFS .... 7 cm (ensemble)
    GGEM ..... 5 cm
    GFS ...... 3 cm

    As you can see, still a wide discrepancy depending on track of system.

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  25. 12Z Euro has dropped out of the race.. now showing only 5-6 cm for Winnipeg Tue-Wed. NAM is the only model now still predicting a significant storm for us. Will it stay the course, or will it cave?

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  26. It should be noted that all our snowfalls thus far have been bigger than expected, so I wouldn't rule out the chance of a bigger than expected snowfall once gain.

    We've had 3 clippers thus far than forecasted 2-5 CM for each one and all 3 we finished with more than 5 CM. Here's an example: last Wednesday's snowfall was forecasted to give 2-4 CM, was then later adjusted to 5 CM and we wind up with 10 CM. Either this is a fluke or for some reason the forecasted snowfall amounts are grossly underdone.

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  27. Well, 18Z GFS has trended towards Nam. It now shows blizzard for Southern Manitoba Tues-Wed.

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  28. That's correct.. GFS now showing 17 cm for Winnipeg Tue-Wed, while NAM cranks out 40 cm from late Monday into Wednesday. Still not ready to buy on to that unless we see some major flips from the other models.. Hopefully we get some consensus soon one way or the other.

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  29. Rob, would you say tonight's 00Z runs will be very telling one or way or another?

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