Wednesday, 1 January 2014

#4, #3 and #2 - Top 10 Weather Stories of 2013 in The Winnipeg Area

(The order of the top 3 weather stories of the year has been determined by the results in the top weather stories poll! Thanks to all of you who participated!)

#4 - Summer heat; better late than never!

     After a rather cool mid-summer, hot and humid conditions returned by mid August, salvaging summer.

     A prolonged period of well above normal temperatures began mid August. In fact, in the last 16 days of the month, highs averaged 30.0°C and lows 15.5°C, both about 5°C above normal for the period. 10 days reached 30°C, above the normal of 5 for August and the most 30°C days in August since 2003. It was also humid with an average daily maximum humidex of 34.6 (in the last 16 days of the month). 8 days saw humidex above 35, well above the 1971-2000 normal of 3 for August. The maximum was 40.4 August 24.

     The peak of the heat occurred during a 4-day heat wave Aug 25-28 when highs reached 33-34°C. This was the longest heat wave since July 2011 (4 days long) and the longest in August since 2003 (7 days long). We hit 30°C for 5 consecutive days, the longest streak in August since 2003. Two high minimum records were broken, a 21.4°C low Aug 24 and a 19.7°C low Aug 25.

     The warmth continued in September, offering an extended summer. With an average mean of 15.4°C, we tied with 1920 for 8th warmest September since 1872.

Sep 6 t-storms after a super-hot day southeast of Wpg
     September 6 featured one of the hottest September days in history. A high of 33.8°C was the hottest in September in 30 years since a high of 38.8°C Sep 2, 1983. Although this was not a record daily high, a low of 17.9°C that day broke a high minimum record. Humidity was also unusually high. A maximum dewpoint observation of 20.3°C was the highest in September since Sep 5, 2005. Humidex peaked at 40.4, only the 4th occurence of humidex over 40 in September since 1953. This was also the latest occurence of humidex over 40 on record.

     The period was also quite dry. From August 19 to September 25 (38 days), just 7.0 mm of rain fell. This was quite reminiscent of last year's 2nd driest September on record.

#3 - The "Perimeter shields" in full action

     The Winnipeg thunderstorm deadzone, Perimeter shield or however else you want to call it, continued into 2013. The year proved to be one of the worst years on record for thunderstorms in Winnipeg. With just a measly 17 thunderstorm days at the airport, this tied for 4th least in a year since 1953.

     The season had a very rough start due to an extremely delayed spring. For the first time since 1995, Winnipeg did not record a single thunderstorm in May. In addition, this was only the 9th occurrence since 1953. Winnipeg finally recorded its first storm on June 10, making it the second latest start to the thunderstorm season (normal first t-storm is April 26). Even more striking, this ended a 289-day streak without a thunderstorm, the longest period without a thunderstorm on record:

Top 5 longest periods without thunderstorms in Winnipeg since 1953
289 days
Aug 25, 2012 to Jun 10, 2013
286 days
Sep 14, 1957 to Jun 28, 1958
271 days
Aug 16, 1967 to May 14, 1968
264 days
Aug 26, 2006 to May 18, 2007
261 days
Sep 10, 2010 to May 30, 2011

     The thunderstorm deprivation continued into part of the summer. Only 2 thunderstorm days occurred in August, tying with 1970 and 1971 for 2nd least on record for August. With 3 thunderstorm days in September, this was only the 4th time since 1953 that there were more thunderstorm days in September than in August.

     And finally, the thunderstorm season only lasted 124 days this year at Winnipeg airport (June 10 to October 11), the 8th shortest season on record.

#2 - Bone-chilling December a fitting end to a "cold" year

     It was the type of December where you only went outdoors if you absolutely had to. With an average mean temperature of -20.9°C, December 2013 was the 6th coldest on record since 1872. It was the coldest December since 2000 and the 2nd coldest since 1893. In total, 9 days dipped below -30°C, above the normal of 3. In addition, 14 days never rose above -20°C, something that is unusual even for January standards. Wind chills were another story, with an average daily minimum wind chill of -35.4. In fact, 12 days saw wind chills below -40, triple the normal of 4 days. A wind chill of -48.0 on December 31 was close to the all-time December low of -50.6 on December 20, 1989. At one point on December 30, the entire province was under a wind chill warning.

     A morning low temperature of -37.3°C on December 15 not only broke a daily record low, but was also the coldest temperature for so early in the season since a low of -39.4°C on December 10, 1893. In addition, a low of -37.9°C on December 31 was the coldest temperature in December since 1933.

     The extreme cold help push some impressive milestones. According to CBC Manitoba, CAA Manitoba reported that December 2013 was its busiest month on record. In addition, Manitoba Hydro reported a record in electricity use across the province on December 23. The cold also delayed trash and recycling collection in Winnipeg.

     Thanks partly to a December that was over 7 degrees below normal, 2013 ties as the 33rd coldest year since 1873. However, it was the coldest year since 1996 and tied 11th coldest in the last century.


  1. A general 5-15 cm looking quite probable for tomorrow across southern Manitoba.

    Winds are expected to be strongest tonight into tomorrow morning from the south, and that's when the main blowing snow and drifting snow is expected in the RRV. Light winds in the afternoon will be replaced by stronger northwesterly winds tomorrow night, creating some more drifting snow, and perhaps some blowing snow on highways.

  2. HI JJ,

    I've noticed with the past few Alberta clippers that the winds are are all over the place. Sometimes they are from the south, sometimes the north and evan east a few times! It totally buffs me. Do you know why the winds are like this, considering the are always coming from the west moving eastward?

    Thanks for the info,

    1. Hi Jeff,
      Yes these lows move in a general flow from west to east, but the actual winds flow counter-clockwise around low pressure systems in the Northern Hemisphere, which is why wind direction changes so much depending on what side of the system you are. Our south wind tonight is ahead of the low pressure system, while our winds will switch to the northwest tomorrow night as the centre of the low pushes to our east.

      As a side note, as a rule of thumb you would get more easterly type winds north of the warm front and more southerly type winds south of it. Westerly to northerly winds occur behind the cold front, or behind the low pressure system.

      Hopefully that answers your question.

  3. Sunday at this point looks like it may feel like the coldest day of the winter due to strong winds. We've been lucky so far in that winds haven't been all that strong with our -30°C temperatures, but Sunday will be a different story. Temperatures around -30°C or well into the -20's will combine with northwest winds of 30 km/h to create unbearable wind chills. Will be a day to stay indoors for sure!

  4. 5-15 cm across southern Manitoba still expected tomorrow. Expect blowing and drifting snow in the morning, tapering off by afternoon and rebeginning tomorrow night.

  5. Good news in the long range or at least we hope. Long range models are really beginning to hint at a warmer than normal period starting late next week...let's hope the models are right on this one. We really deserve it.

  6. Well there you have it, another major storm to add to our list of major storms of the winter. 10-15 cm expected today. The winds will make highway travel horrible tonight with significant blowing snow this evening and overnight.

  7. What has produced this pattern of Brutally cold weekdays followed by stormy warmups near weekends. Is it this winters version of the perimeter shield or the spring n summer version of rainy weekends only? Lol

  8. Looks like about 7-9 cm at my place in south St Vital as of 4:30 pm... as a storm total so far. Very difficult measure today due to severe drifting this morning. Heavy band still to come through in the next couple hours so wouldn't be surprised to see another 4-7 cm before all is done.

  9. Strong northwesterly winds develop this evening at 30 to 50 km/h with higher gusts at times, strongest south of Winnipeg. Near blizzard conditions around Winnipeg expected, with blizzard conditions south of the city. This is expected to continue through the night with diminishing winds tomorrow, but breezy conditions expected with still some blowing and drifting on highways.

  10. Number 1 story of 2013 coming tomorrow morning. Sorry for the delay.. This storm has distracted me a little!

  11. I'm up to 13 CM or so here in Windsor Park as of 6 PM but heavy band of snow has been falling in the city for the last hour or so, so probably at or close to 15 CM here when it's all said and done.

    1. Thanks for the report. I've had somewhere around 11-13 cm now as well.

  12. I'm making the final snowfall measurement at 14 CM at my place in Windsor Park. And now we deal with the blowing and drifting as well as the incoming cold snap. How fun.

    1. My preliminary amount is 12-13 cm at my place (will compare with other nearby measurements today to confirm). Got a water equivalent of 10.9 from the afternoon/evening snow... which might be too high thanks to blowing snow into the gauge.

  13. Models still insisting at a warmer than normal pattern starting Thursday and going into the week beyond. Let's hope the models are right. We deserve it.