Sunday, 4 November 2012

2012 Southern Manitoba Thunderstorm Season In Perspective

     First, let me introduce you to this new yearly post. I've personally been keeping stats on thunderstorms in southern Manitoba since 2010. I note every single day that lightning was detected, using lightning detection products from The Weather Network, Environment Canada and Intellicast. I also keep track of when severe thunderstorm warnings were issued by Environment Canada to get stats on the severe thunderstorm season. To compliment this data, I also note in what part of southern Manitoba these events occurred. To do this, I have divided southern Manitoba into 6 regions: West, Southwest, South, Southeast, East and Interlake. Before reading further, I highly recommend that you check out where exactly I consider these 6 regions to be by checking out this map. With this map, you will know exactly where I am talking about and which region your city or town is.
     Now, let's look at the 2012 thunderstorm season, starting with its length:

     The thunderstorm season began earlier than normal; it typically does not begin until April for most areas (normals can be found here). This was in large part thanks to the unprecedented warmth we experienced in March as the jet stream rose way further north than usual. The mid-March start was also about a month earlier than in 2010 and 2011.
     It was a loud start as well. Thunderstorms on March 19 were widespread and dumped torrential downpours and gave frequent lightning. This event brought Winnipeg its earliest recorded thunderstorm on record.
     Now, how about the frequency of thunderstorms, severe thunderstorms and tornado warnings per region:

     Southwestern Manitoba was the 'stormiest' with 74 thunderstorms days and 19 days with severe thunderstorm warnings. This continues the trend of the past couple years as this region had the most in both 2010 and 2011 as well. For southern Manitoba as a whole, there were 34 severe thunderstorm warning days, much more than in 2011 when there were only 24. However, 2011 was abnormally less active. I do not have the actual numeric normal considering I only have 3 years of data.
     In the city of Winnipeg specifically, there were about 25 or 26 thunderstorm days in 2012, which is right around the normal of 27.
     Now, let's take the 109 thunderstorms days, 34 severe thunderstorm days and 2 tornado warning days in southern Manitoba as a whole and divide it monthly. Here's what we get:

     As per usual, June, July and August were the most active months of the year.
Arborg possible tornado June 16th by Kyle Kearney
     Tornado-wise, it was a very quiet year in Manitoba; intriguing when you consider that our western neighbour, Saskatchewan, had a record year for tornadoes.
     The only possible tornado to have touched down was in Arborg on June 16th. However, it was unconfirmed by Environment Canada. As a result, not one single tornado was confirmed in Manitoba this year. This is much below the normal of 7 to 10 tornadoes in Manitoba per year.

     To finish off, here's a couple notable thunderstorm events this year:

1-Swan River July 11 severe thunderstorms dump 77 mm of rain, causing severe flooding
2-Stormy May
3-July 29 windstorm
4-August 1 windstorm
5-July 25 Steinbach rainstorm dumps up to 111 mm of rain in a couple hours causing severe flooding
6-June 9 hailstorm

     I will have a country-wide severe thunderstorm season summary up in the next couple weeks.


  1. Thankfully it looks like the precipitation will remain as rain tomorrow for us in the Winnipeg area. Showers are expected to begin sometime later in the afternoon and continue in the evening. 2 to 5 mm will be possible, especially in the Interlake. The precipitation could turn into snow later in the evening, but it shouldn't accumulate to much here, but may accumulate to a few cm in the northern Interlake.

  2. Drizzle or light showers will end later this morning if you're seeing any. Looks like about 5 mm fell over the city last night, about half of that as snowfall. Due to above zero temperatures overnight, any snow that fell has melted for the most part.

    Still great uncertainty about the late week/weekend storm. Models are actually becoming in more disagreement as the day gets closer right now, so I think we will have to wait a few more days. Right now, possibilities vary from just a few cm, to 30 cm, to an ice storm followed by a snowstorm... Will be interesting indeed.

  3. Looks like this post will have to be updated! Lightning detected just south of the city right now, and reports of thunder and lightning in La Salle. Wow!