Sunday, November 13, 2016

Record warm start to November.. but reality check by late week as potential winter storm looms for southern Manitoba

It's been an exceptionally warm November so far across southern MB and much of the Prairies. For Winnipeg, the first 10 days of November this year have been the warmest such period in over 140 years of records. Simply put, Winnipeg has never had a warmer start to November since records began in 1872.  Temperatures in Winnipeg so far are averaging a phenomenal 8.5C above normal since Nov 1st, with an average of +6.6C through Nov 13th (normal is -2C for this period)  That is more typical of mid October than mid November!  9 of the first 13 days this month have hit double digits, with a record 18.8C on Nov 9th, the latest date on record that the city has hit 18C or more.  Daily minimums have been mild as well with lows generally staying above freezing, and only 2 days below -2C.  The weather has been so unusually mild, grass is still green in the city and there are reports of flowers reblooming in parts of southern MB.  An exceptionally low snowpack across Canada so far this year together with record low Arctic sea ice has kept Arctic airmasses from intensifying across the north and pushing south. In addition, strong Pacific storms over the Gulf of Alaska have spread persistent warmth across southern Canada over the past 2 weeks, effectively blocking any incursion of cold air southward.  

Charts showing temperatures past 30 days in Winnipeg (left)
and temperature anomaly map over the US this November (right)
Note greatest anomaly core (> +8C) over southern MB 

Chart showing warmest starts to November in Winnipeg since 1872

UPDATE: Winnipeg records warmest first half of November in over 140 years 

It's official.. Winnipeg has never seen a warmer first half of November than this year. Over the first 15 days of the month, the average temperature in Winnipeg has been +6.3C, easily the warmest first half of November here since records began 144 years ago in 1872.  It beat out the previous warmest start to November in 1981 and 1931 by almost 1.5C, a large margin for long term climate records. The average of +6.3C was more typical of mid October here, and was an astounding 9C above the average temperature of -2.6C which is normally expected over the first half of November in Winnipeg.  Truly a historically warm start to November.  

Late week winter storm looms.. 

GFS outlook for Friday evening Nov 18th showing
major winter storm possible for southern MB
But this is the Prairies and it's mid November. The abnormal warmth has to come to an end at some point, and long range models are indicating that the transition to winter may be coming to southern Manitoba by the end of the week as a strong storm system tracks across the northern Plain states. There is still considerable uncertainty on the path of this storm and its possible impacts to southern Manitoba, but the potential is there for a significant winter storm to affect portions of southern Manitoba late in the week, especially over the Red River valley and southeast Manitoba. This system may bring the first major winter storm to parts of southern Manitoba on Friday Nov 18th-Sat Nov 19th with heavy snow, strong winds and possible blizzard conditions. This system is still 5 days out and details such as storm track, intensity and precipitation distribution need to be refined in the days ahead as models get a a better handle on this storm. In the meantime, enjoy the next few days of continued mild weather and prepare for a sobering reality check to winter by the end of the week.     

GEPS ensemble 24 hr precipitation outlook valid Sat morning Nov 19th
Highest threat for heaviest precip over southern MB is over SE areas  


  1. Model guidance this morning has trended east on the storm, keeping bulk of snow southeast of Winnipeg.. mainly over ND, NW Ontario, MN and extreme SE MB. So the trend right now is for this thing to miss us.. BUT.. it's still early, and I can't say with any confidence that the models won't trend back west in a couple of days. if the models continue this trend through Wednesday, then I'll have more confidence in a miss scenario. Note that at this point, it's best just to focus on ensemble products, and don't favour any one deteriministic model solution over another.

  2. Well, looks like storm will be a non-issue for southern MB as all model guidance continues to show main track well south and east of us over southern Minnesota then into Lake Superior.. much too far east to have any impact in southern MB. However, if you have travel plans to Minneapolis or Thunder Bay this weekend, be prepared for wintery travel conditions over NW Ontario and northern Minnesota Friday into Saturday.

  3. Rob,

    Is it possible that we may end November with little or snow on the ground as result of the big bullet we will be dodging Friday?

    1. It's certainly possible.. we've had other Novembers with very little snow on the ground by the end of the month. In fact, we've had some Decembers with very little snow on the ground through Christmas.. (such as 1997)

      Whether or not this year will see little snow cover remains to be seen. We get cold enough for snow over the weekend into early next week, and there may be a weak impulse that could give us some snow during that time. We then should be edging back above normal by the end of the week possibly lasting into the end of the month. If that's the case, we may see every little snowfall this month. But again, too tough to say at this point. It doesn't take much to get a weak system passing through to give you some accumulating snowfall.