Wednesday 11 December 2013

Southern Manitoba 2013 T-storm Season Statistics!

July 13, 2013 southwestern Manitoba; most significant storm event of season; @lovestormsmb and I were there

    For the 4th consecutive year, I have gathered statistics on thunderstorm and severe thunderstorm frequency across southern Manitoba. An explanation of how I gathered these statistics as well as notes on accuracy can be viewed here. I have divided southern Manitoba into 6 regions: west, southwest, south, southeast, east and Interlake. These regions can be seen here. I understand the zones are not equal in size; I plan to try to improve this next year. Lastly, I'd like to thank you in advance for taking the time to read this post as it is one of my favourite posts of the year!

     The 2013 thunderstorm season was less active than in 2012 in all regions of southern Manitoba. The greatest decline in thunderstorm days was in the Interlake, southeast and east parts of Manitoba where in some cases there were more than 10 thunderstorm days less than in 2012. The Interlake saw the greatest decline, dropping from 67 thunderstorm days in 2012 to only 55 this year. In total, there were 89 thunderstorm days across southern Manitoba this year, compared with 109 last year.

     One reason for the decline is because 2012 had a very long thunderstorm season, lasting from March to November. This year, the first thunderstorm did not occur until April 30, and the last on October 11 putting the season at 165 days long, compared with 237 days last year.

     The season began quite late in some areas this year, in large part thanks to an incredibly late spring. The south, Interlake and east zones did not see their first thunderstorm until May 14, 2 months later than last year. On a more local scale, Winnipeg saw its first t-storm on June 10, the second latest start to the thunderstorm season since 1953.

     Again in Winnipeg, there were only 17 thunderstorm days this year at the airport, tying for 4th least in a year since 1953. It just so happens that one of the years we tied with was 2011. This really follows the trend of the past few years of below normal thunderstorm activity in the city. The last time we had an above normal season was 2007. The last 6 years have averaged some 6 days below the 1981-2010 and 1971-2000 normal of 26 to 27 days.

    In comparison, Brandon had 23 thunderstorm days this year, and I recorded 20 here in south St Vital.

     The map to the left shows the number of days with a severe thunderstorm warning issued by Environment Canada in each warning zone. It appears southwestern Manitoba was the busiest this year for severe thunderstorms. The season in Manitoba lasted from June 9 to September 26, or 110 days, compared with 116 days last year. Click here for a map of the length of the severe thunderstorm season in each warning zone this year.

     The last map I have is of tornadoes, as seen to the right. The colours in the warning boxes represent the number of tornado warning days this year, and the dots represent unconfirmed (possible or probable) and confirmed tornadoes (coloured by intensity). Only 4 tornadoes were confirmed, but many more may have touched down.

     The most notable twister was in Sioux Valley, First Nation, west of Brandon on July 18. It was a strong EF-0 tornado, and moved right through town, destroying a few homes and leaving a few injured. Other than that, the most significant potential tornado event was in the Pipestone to Hartney area on July 13. Significant damage occured in the area, including to the arena in Pipestone which half of it had been flattened. It is still up in the air wether a tornado occured or not. Either way, according to Discover Westman, some recall the storm as being the worst storm in recent memory in southwestern Manitoba.

     The storm also only worsened the flooding conditions in Reston, which saw yet another round of biblical rains with the storms. In fact, the town had received about 352 mm of rainfall in just a 24 day period from June 20 to July 13 according to Manitoba Agriculture.

     In addition to the rains and winds, 9 cm diameter hail was measured in southeastern Saskatchewan with the storms.

     Lastly, the following graph summarizes the number of thunderstorm days, severe t-storm warning days and tornado warning days across all of southern Manitoba per month:

Thanks for reading! A summary of the severe storm season across Canada will come late next week.


  1. Maps have been updated for better viewing. Special thanks to Brad from A Weather Moment for the suggestion and help with making the improvements.

  2. Record breaking 200+ blogviews in the past 24 hours, largest amount since I started 2 years ago. Thanks to everyone for taking the time to visit!

    About the forecast; the warmer weather models had advertised for next week looks to be becoming more of a reality. However, I wouldn't get too excited because it may only last a day or two and be at the beginning of the week. There are hints already at another significant push of arctic air sometime afterwards.

    As for Saturday, I'm still expecting some light snow, especially in the morning. A couple cm can't be ruled out.

  3. Wow....just when you thought it can't possibly get colder, well wrong.....Yikes if the long range prediction from the models comes through latter half of next week and beyond it's going to be dangerously cold. Potentially coldest temperatures in years of tap. Hard to imagine temps of - 40C or colder at this time of year but that's model land is saying. And that's - 40C before windchill factor.

  4. I see models are hinting at another major storm Mid week next week but not yet convinced it will hit us but the chance is definately there and then it's back to brutal cold.

  5. 1.4 cm with this snowfall as of 11:30 am at my place. Pretty much right on par with what was expected.

    HUGE warmup for Monday with temperatures potentially getting as high as -2°C to -4°C. Wont that feel nice? There will be a bit of a breeze.

    And yes, some models hint at a stronger system mid next week... we'll see.

  6. Hi JJ,
    do you think EC's low of -34 tonight is possible, or are they just trying to scare us?

    1. Forgot to mention how interesting the manitoba T-storm post was, loved it!

    2. Lows in the -30's definitely possible tonight. I'm personally aiming for something around -31 or -32°C... but I suppose -34°C is not out of the question.

    3. Will be interesting to see if the GEM regional model is correct for tonight in giving lows of -36°C.

    4. Birdshill NE is reporting -37 this morning Cooks Creek?

    5. GEM Regional performed excellently. Low around -35°C or so in Winnipeg. Wont know exact low until this afternoon

  7. Lows around -39°C in the Interlake this morning, and according to Rob from Rob's Blog about -37°C in Winnipeg and possibly a record. I'll make a post with official lows across southern Manitoba this evening... wont be able to this afternoon.

    1. Quite extraordinary considering the old record today is back in 1879 (134 years ago)!

  8. Hi there! Do you use Twitter? I'd like to follow you if that would be ok.

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    1. My Twitter handle is on the right under author. @jjcwpg

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