Saturday, December 03, 2016

Mild weather continues into early next week.. then Arctic plunge moves in! Significant snow possible Tuesday.

The above normal temperature pattern which has persisted over southern Manitoba for the past 6 weeks will continue through the weekend into early next week.. but a major pattern change next week will bring an end to the mild weather as a strong push of cold Arctic air floods across the Prairies from the west.  This will bring the first real cold weather of the season to southern Manitoba with temperatures in the minus teens and lows in the minus 20s by the end of the week.. a shocking change from the unusually mild weather we have been experiencing since late October (today will mark Winnipeg's 44th consecutive day above normal since the warm weather streak started Oct 21st). But first we'll have to deal with a minor system passing through southern Manitoba Saturday night into Sunday morning that will bring a couple cm of snow along the way. That will clear out by afternoon with a pleasant end to the weekend as temperatures remain well above normal for early December with highs around the freezing mark (normal highs are now -7C with lows of -16C!)
NAM model valid 3 am Tuesday morning shows potential storm
system over southern Manitoba with widespread snow
causing significant impact to the Tuesday morning commute
Stormy Tuesday?  Things start to get interesting Monday night into Tuesday as a storm system over Montana tracks towards the Red River valley, possibly bringing significant snowfall across southern Manitoba, including Winnipeg. Most models are suggesting that southern Manitoba could be seeing 10-20 cm of snow with this system as well as increasing northwest winds and falling temperatures on the backside of the storm Tuesday. One model however, the Canadian GDPS, is suggesting that the storm will mainly miss southern Manitoba before clipping southeast Manitoba Tuesday night into Wednesday. This solution could easily change over the next few days, so keep up to date on this potential storm system for southern MB that could have significant travel impacts Monday night into Tuesday. Regardless of what happens, be prepared for a big change to significantly colder weather by the middle of next week!     


  1. Models continue to struggle with how this system will play out over southern MB Monday night through Tuesday.. but it's looking more and more likely that southern MB will be impacted by this system. 12Z GDPS has come more in line with the other models bringing a stronger low into southern MB Tuesday with at least 10-15 cm snow across RRV and SE MB, including Winnipeg. Latest 18Z NAM and 12Z ECMWF now take the main center of the low through the MB interlake which would shift the heaviest snow through westman and the interlake regions, with lower amounts over the RRV (although still at least 10 cm) Models are struggling with a possible double center low, one over SW MB and one in ern ND, and which one will take over as it moves across southern MB Monday night into Tuesday. Latest guidance now suggesting the main energy will focus on the SW MB low taking it into the interlake region rather than developing the ern ND low, which would have more serious impacts for Winnipeg/RRV if that took over. So still a lot of uncertainty on the details of the storm in terms of heaviest snowfall and strongest winds, but increasing odds southern MB, including Winnipeg, will be seeing impacts from this system late Monday into Tuesday. Stay tuned..

  2. Models coming into better agreement today on this upcoming winter storm system, now favouring a stronger low tracking over SE MB as the ern ND low takes over, while the incoming SW MB low weakens. This will mean more snow likely for Winnipeg and the RRV, with the bulk of the snow falling Monday night into Tuesday with 10-20 cm possible here by Tuesday evening. Additional snow is likely Tuesday night (possibly another 5-10 cm) with increasing NW winds as the low tracks into NW Ontario, with blowing and drifting snow likely. All in all, a good 15-30 cm possible for Winnipeg/RRV between Monday evening and Wednesday morning. Tuesday commutes will be the worst.. both morning and evening with lingering travel impacts into Wednesday. That's how it's looking right now.. we'll see if the story changes over the next day or so..

  3. Finally a kick Ass storm coming!

  4. Rob, got a question for you. Why is SW under the WS Warning already while Winnipeg and SE MB is just under the ws watch? I believe the impacts of this storm is expected to be just as significant here as in SW MB, Correct?

    1. It's a matter of forecast confidence, and when the storm is expected to start. Snow is expected to start over SW MB Monday morning and persist into Tuesday, and generally, a winter storm warning is issued within 12 hours of onset. Snow is expected to start later over SE MB, not until Monday evening.. and this gives forecasters more time to assess where warning conditions may be met further east. In the meantime, a watch is issued to give people a heads up on the potential for severe winter weather in the days ahead.

      Note that model guidance tonight is trending further south and east of Winnipeg in terms of heaviest snow with the main storm system on Tuesday.. as the storm center loops over Lake of the Woods area before heading east. This gives less snow to Winnipeg (maybe 10-15 cm) with heavier snow over southern RRV and northern ND. This is why a winter storm watch is prudent for SE MB.. still a lot of uncertainty about how this thing will pan out. Every new model run seems to be giving a different answer..

  5. This will be another Winnipeg bust! Potential for 30cm and get 10cm. Figures.

  6. No sooner do the models agree than they dont...

  7. Well, we're back in business.. models trending back towards a good dump for Winnipeg.. although it will start a bit later.. around 3-4 am overnight instead of this evening. Look for about 5 cm by the Tuesday morning commute, and another 10 cm by the afternoon commute. Winds will also be picking up gusting to 60 km/h by morning so blowing and drifting snow will compound issues. Will not be a good day on the roads, especially outside the city. Snow should continue much of Tuesday night with another 5 cm before gradually tapering off Wednesday. Storm total likely in the 15-25 cm range for Winnipeg by the time it tapers off Wednesday, with the bulk of the snow falling between 3 am Tuesday and 3 am Wednesday. Should be a pretty good wallop. Much colder air moves in behind storm for Thursday into next week.