Southern Manitoba 2013 Thunderstorm Season Statistics

Editor’s Note: The following is a guest post by @jjcwpg, originally posted here and has been updated with some relevant links from A Weather Moment.

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

Number of days in 2013 thunderstorms were observed in each region.
Number of days in 2013 thunderstorms were observed in each region.

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.

Number of days in 2013 a severe thunderstorm warning was issued for each region.
Number of days in 2013 a severe thunderstorm warning was issued for each region.

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.

Number of days a tornado warning was issued in each region through 2013. Also plotted are confirmed and unconfirmed tornado events.
Number of days a tornado warning was issued in each region through 2013. Also plotted are confirmed and unconfirmed tornado events.

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 occurred 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 occurred 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:

Summary of all thunderstorm statistics for all of Southern Manitoba broken out by month.
Summary of all thunderstorm statistics for all of Southern Manitoba broken out by month.

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

Red River Valley Set to Bake Today

Some of the hottest temperatures of the year will be seen today in the Red River Valley as extremely warm air is brought into the province by a low pressure system passing through the northern Interlake.

850mb temperatures from the GEM-REG

850mb temperatures from the GEM-REG for late this afternoon. Temperatures are expected to peak at just over 25°C at 850mb over the Red River Valley today.

Southerly winds have brought some of the warmest air yet this year over southern Manitoba. 850mb temperatures have climbed to 25°C today which, when combined with southerly winds at the surface, will help to push our daytime highs towards the mid-30’s. There is fairly good agreement among the models that winds will remain southerly in the Red River Valley through the day; this will eliminate any significant downslope effects and make temperature forecasting a little bit easier.

In general, daytime highs should range from 34-36°C through the RRV tomorrow, with the warmer temperatures closer to the American border. There is a slight chance that a few areas in the SW RRV could see highs push a degree or two higher than that (35-37°C), but such temperatures would be fairly localized. Winnipeg will have a chance of breaking it’s record high for today, which was set in 1972 when the temperature climbed to 36.1°C. It’s by no means a guarantee that we’ll break it, but we’ll certainly take a good run at it.

Dewpoints will climb to around the 18°C mark, however some areas may see dewpoints peak at 21-22°C before we start mixing air near the surface a little deeper into the atmosphere. This will result in humidex values between 39-45. It’s quite likely we’ll see a humidex advisory issued by the Winnipeg SPC later today.

Manitoba Health suggests Manitoba residents take precautions against heat-related illnesses whenever the humidex climbs above 37. Manitoba Health advises the following:

  • Stay aware and be prepared
    • Know daytime and night-time temperatures-both outdoors and indoors- by checking your local weather forecasts and the thermostat in your home.
    • Stay up to date on weather alerts so you know when to take extra-care.
    • If you have an air-conditioner, make sure it’s working properly before the hot weather starts.
  • Stay hydrated
    • Drink plenty of water (that’s the best liquid) before you feel thirsty.
    • Avoid alcoholic beverages, as they can increase the amount of water lost by the body.
  • Stay cool and keep out of the sun
    • Plan outdoor activities for cooler parts of the day, but remember to wear insect repellant since mosquitoes are out too.
    • If you are outdoors during the hottest part of the day, shade yourself from the sun with an umbrella or a wide-brimmed hat with lots of ventilation (to allow the sweat on your head to evaporate), wear loose-fitting, breathable, light-coloured clothing, and remember to wear sunscreen to limit ultra-violet (UV) ray exposure.
    • If there is no air-conditioning at home- go to a cool place such as an air-conditioned mall, public library, or community centre.
    • Take a cool bath or shower or go for a swim to cool off.
    • Avoid using your oven or other appliances that could heat your home more.
    • Limit physical activities during the hotter parts of the day or exercise in an air-conditioned place.
  • Take care of yourself and others
    • Check on family members, neighbours and friends – especially older adults and those with chronic conditions. Visiting is best because it is easier to identify signs of heat illness that could be missed over the phone.
    • Never leave people or pets in your care alone in closed vehicles or direct sunlight.

Heat and Your Health; Manitoba Health

A cold front will sweep through this evening, bringing more seasonal air back to the province. There is very little chance of any precipitation with the passage of this front.

The rest of the week will bring closer-to-seasonal temperatures with daytime highs near 28°C. The normal daytime high for Winnipeg for this time of year is about 22°C. The normal overnight low is around 9°C. Our blast of hot weather will likely ensure that Winnipeg has it’s 14th consecutive month with above-normal temperatures. We’ll have our regular post on Friday, and then two posts on Saturday: the regularly scheduled Elsewhere in Weather News and a climate summary of August/update on 2012.

Record Setting Heat Across the Prairies

Summer has decided to hang on and not leave us quite yet, bringing record-breaking heat to much of the Canadian Prairies. A large upper ridge build into the region on Tuesday and Wednesday, pushing the jet stream all the way up to the 60th parallel which has allowed a hot, dry southwest flow to remain in place over Alberta, Saskatchewan and Manitoba for days on end. Records have fallen left in right, with some of the highest daily quantities of records being broken at once over the last two days.

How long will this heat stay with us? How hot is it going to get? Click through to read more!

On Wednesday, September 7th, 22 record highs were broken across Alberta, Saskatchewan and Manitoba:

Daily Record Temperatures set September 7, 2011

Location New
Cold Lake 30.4 27.8 1998 1953
Fort Chipewyan 27.0 25.0 1937 1884
Fort McMurray 31.0 28.3 1949 1944
Jasper 29.6 29.1 1998 1943
Whitecourt 29.1 26.7 1949 1943
Saskatoon 33.4 31.5 1990 1892
Collins Bay 28.0 18.8 1980 1972
Hudson Bay 30.7 30.2 1990 1943
Key Lake 30.0 21.5 2005 1977
La Ronge 29.6 27.7 1980 1923
Meadow Lake 30.2 28.5 1998 1924
Melfort 31.7 31.5 1980 1902
Nipawin 33.0 32.2 1934 1927
North Battleford 33.0 32.2 1893 1880
Rosetown 32.6 32.0 1991 1937
Stony Rapids 27.0 22.7 2005 1960
Fisher Branch 29.7 29.5 1980 1977
Gimli 28.3 27.9 1980 1944
Lynn Lake 29.0 23.9 1980 1952
The Pas 30.3 29.4 1934 1910
Thompson 27.6 24.5 1990 1967

Of note on this day:

  • North Battleford broke a daily record high temperature that was set in 1893, a record 118 years old.
  • Many record highs were broken by at least 2 or 3°C, and some by nearly 10°C.

On Thursday, September 8th, 22 record highs were broken across Alberta, Saskatchewan and Manitoba:

Daily Record Temperatures set September 8, 2011

Location New
Cold Lake 30.8 29.8 1981 1953
Coronation 32.2 31.2 1981 1928
Fort McMurray 32.1 30.4 1981 1944
High Level 27.4 26.3 1995 1967
Jasper 30.0 29.8 1998 1943
Sundre 26.9 26.0 1994 1985
Waterton Park 28.3 28.0 1994 1966
Saskatoon 34.1 33.5 1981 1892
Collins Bay 24.6 24.1 1981 1972
Hudson Bay 31.7 30.2 1990 1943
Kindersley 33.2 32.8 1981 1913
Leader 34.2 33.5 1981 1924
Nipawin 32.8 32.2 2003 1927
Stony Rapids 24.1 22.3 2003 1960
Fisher Branch 32.1 32.0 2003 1977
Gimli 31.1 30.0 2003 1944
Island Lake 28.1 25.2 2009 1971
Lynn Lake 26.6 23.6 1980 1952
Pinawa 30.7 30.5 2003 1964
Sprague 30.9 29.4 1932 1915
The Pas 30.3 27.5 2003 1910
Thompson 28.0 25.8 2003 1967

And today, September 9th, 2011, 18 records were broken:

Daily Record Temperatures set September 9, 2011

Location New
Edson 28.7 27.8 1963 1910
Fort Chipewyan 30.0 27.0 1981 1884
Fort McMurray 32.7 32.4 1981 1944
Jasper 30.4 27.2 1944 1943
Sundre 28.9 25.8 2006 1985
Waterton Park 28.5 27.4 2006 1966
Whitecourt 29.7 29.0 1981 1943
Collins Bay 28.0 23.0 2003 1972
Hudson Bay 31.7 29.0 1998 1943
La Ronge 31.0 26.6 1994 1923
Nipawin 32.1 29.2 1981 1927
Stony Rapids 29.1 22.0 2006 1960
Fisher Branch 31.8 31.5 1982 1977
Gimli 31.1 31.0 1982 1944
Lynn Lake 31.1 26.6 2003 1952
Sprague 31.9 30.0 1931 1915
Swan River 31.7 30.0 1998 1908
The Pas 30.7 26.8 2003 1910

This record-setting heat is all thanks to an impressive upper ridge that has built into the Prairies. This is a feature located high in the atmosphere that causes a large area of air to subside (move downwards). Combined with the fact that they build up from the south, they bring a lot of warm air along with themselves, and often result in a large area seeing sunny skies, light winds and hot, dry weather.

The upper ridge will remain in our area for the next couple days, with daytime highs remaining in the low 30°C range. Winnipeg has an honest shot at breaking our daily record high temperature tomorrow which sits at 32.4°C. Things will abruptly change next week however. On Monday a low pressure system will pass by to our north and drag a cold front down across the province. Through the following days, a large ridge of high pressure will build in from the northwest, bringing significantly cooler temperatures than the past week:

GFS Temperatures Valid 06Z Thursday 15 Sept
GFS Surface Temperatures Valid 06Z Thursday 15 September

Currently it looks like next Wednesday and Thursday will be the coldest of the days, with highs struggling to get as high as 15°C. While the last week has been a beautiful late-season blast of summer, fall is set to make an aggressive entrance early next week.

Summer is Here!

As Manitobans in the Southwest corner of the province continue their battle against the swollen Assiniboine river, mother nature has granted us tremendous weather.  Clear skies and warm temperatures have spread throughout much of the province, giving us a reprieve from the cool and cloudy conditions that we seemed to be entrenched in for…well a long time.  But will it last?

An “omega block” set up across the Prairies late last week, with the jet stream rounding the base of an upper low off the coast of California and then heading up to the Northern Prairies, arching over an upper high that had built into the central Prairies and then heading south and exiting the continent around the bottom of an upper low off the east coast.  This allowed a large-scale southerly flow to develop and warmer air to push northwards into Canada.  As a side note, this is called an “omega block” because the jet stream curves in the shape of the Greek character omega, and it’s a fairly stable pattern that doesn’t move very quickly, hence it’s a blocking pattern.

Over the past few days, a shortwave has pushed into Alberta and the blocking pattern has begun to shift.  Instead of completely collapsing, it seems to have rotated such that the block is now aligned northwest-southeast instead of north-south.  This will allow cooler air to push into the western Prairies (as is seen today with cooler temps and rain through southwest Saskatchewan) while building the warm air over the eastern Prairies.

Stormier weather is brewing to our south, though.  A significant shortwave is expected to eject northeast out of a stationary long-wave trough on the upper-west coast on Thursday night, moving into the Dakotas by Saturday.  This feature has a lot of uncertainty attached to it at the moment, but the models have been pushing the precipitation envelope further north with each successive run, which puts Winnipeg increasingly into the risk of some rain ruining our lovely weather.

12 Hour QPF valid 06Z Sun 22 May from the GFS Model

I’ll provide some further details about this system in a couple days when it’s beginning to resolve a bit better.  It looks likely that areas south of Morris in the Red River Valley will likely see some accumulating rain this weekend, but first we get to enjoy several more days of hot, sunny weather.  Get out there and enjoy it!