Monday, 31 December 2012

#9 - Top Ten Weather Events of 2012 in the Winnipeg Area

May's Wild Thunderstorms

     In southern Manitoba, May was quite a month for thunderstorm-lovers with many convective events; most notably on May 14, 18, 22/23 and 27.

Little rain, just blowing dust. By BobLedoux near Ft Whyte
     A cold front moving across southern Manitoba in the evening on May 14 sparked off thunderstorms, despite a great lack of humidity. This lack of humidity, with surface dewpoints generally in the low single digits, was the perfect recipe for a severe wind event thanks to ''evaporative cooling''. (Definition of evaporative cooling here)

     The thunderstorms dropped very little rain, but brought severe gusts of wind and interesting cloud formations. Sudden gusts of 80 to 100 km/h were common across the RRV, with a maximum of 85 km/h at Winnipeg airport with the first cell to move through the city. Some regions were hit repeatedly as several cells formed one after another. In addition, they actually formed a bit ahead of the main front, meaning we had to contend with another round of severe wind with the front itself later in the evening. Winnipeg airport recorded a gust of 93 km/h with the front, after the storms. Some trees and even semi-trailers were toppled, and there were numerous power outages in many communities throughout southern Manitoba. Most outages were restored quickly, except for a few regions north of Portage such as St. Ambroise, which lost power for several hours after the storms. The winds were also blamed for a wall collapse at the construction site of Winnipeg's new football stadium.

Photo by Hannah Shiffman via CBC Manitoba
     Thanks to very dry soil conditions, the winds also produced dust storms, a rarity in southern Manitoba. Near zero-visibility in blowing clouds of dust was seen locally in rural areas. According to The Weather Network, some callers to their storm line said they had to pull over as visibility reached near zero in blowing dust and dirt. The following day, some farmers even woke up to ''dirt drifts'' in their fields. Within Winnipeg, blowing dust was mainly seen in open areas and northern parts of the city.

     These storms claimed one life on Lake Manitoba. Two men were out fishing on the lake when the wind hit with little warning. The strong winds and heavy waves overturned their boat. One man made it to shore, while the second was swept away by the waves. Searchers combed the area for several days afterwards for his body, finding it on May 23, 11 km away from the location of the capsize.

     (*Here's a list of videos I find give a great idea of the conditions felt on May 14: Video 1, Video 2, Video 3*)

     On the evening of May 18, a retreating warm front was the cause of another thunderstorm outbreak in the RRV and southeastern Manitoba. Of note, there was a very tight temperature gradient with this front. At 5 PM, while it was only 15°C in Minot, it was 35°C in Fargo.

Storm resembled flying saucer. By Rebecca Schleicher
     Lines of thunderstorms formed just west and southwest of Winnipeg by 7:30 PM and swept through the city between 8 and 9:15 PM. The storms trained over western, central and northern sections of the city, giving long-lasting torrential downpours. A swath of 25-35 mm of rainfall fell through these parts, while only 5 to 10 mm fell in east, southeast and extreme northwest sections of the city. A peak rainfall rate of 133 mm per hour was recorded in Charleswood at 8:11 PM. In addition, hail as large as quarters fell in central and northern parts of the city, and lasted long enough to accumulate locally. Lightning was frequent, and the heavy rain flooded a few streets. The rain was blamed for an apartment roof collapse at the corner of Aikins Street and Atlantic Avenue. Residents were evacuated and there were no injuries. Some traffic and street lights lost power as well. These storms however were a blessing to the fire situation in southern Manitoba.

     (*Here's a list of my favourite videos of the thunderstorms on May 18: Video 1, Video 2, Video 3, Video 4*)

Photo by John Kristalovich
     More strong thunderstorms made their appearance late on May 22 and early May 23. This time, the main story was the magnificent display of lightning in the RRV late evening and early overnight; definitely not something we see every May. Lightning was almost constant at times and there were many cloud-to-ground strokes. Rain in Winnipeg was not impressive with only a general 2 to 6 mm across the city. Heavier amounts of 10 to 20 mm fell to the east and northeast of the city, with locally higher amounts.

     (*Some awesome videos of the lightning May 22/23: Video 1, Video 2, Video 3*)

     Yet another round of storms drenched the Winnipeg area on May 27. A line of heavy elevated thunderstorms swept through the city near 6:30 PM, locally dumping a good 10 to 15 mm of rainfall in as little as 10 minutes. Lightning was not frequent. Storms continued on and off through the evening until about 9:30 PM. By the end of the day, in addition to showers earlier in the day, as much as 20 to 35 mm of rainfall had fallen in southern and northern parts of the city.

     All these storms along with some rain events in between brought monthly totals as high as 130 mm in parts of northern and western Winnipeg. This is more than double the normal of 57.4 mm for the month of May. However, amounts were lower in other parts of the city with as low as 85 mm in parts of the southern and eastern ends; areas that missed out on heavy rains on May 18 and 28. The 98.0 mm at the airport made it the 21st wettest May on record.

Flooding in Winnipeg May 18, by Charmaine Straker
 This post contains information, photos or videos from the following sources:

City of Winnipeg water and sewage department rainfall reports
CTV Winnipeg
CBC Manitoba
The Weather Network
Rob's Blog
Environment Canada Weatheroffice

Sunday, 30 December 2012

#10 - Top Ten Weather Events of 2012 in the Winnipeg Area

Cold September Nights

     Although daytime temperatures were only a few degrees below normal in Winnipeg on the coldest days in mid September, they fell quite rapidly at night. On a few days, the difference in temperature between night and day was more than 20 degrees! This may have been thanks to very dry soil conditions which helped accelerate heat loss from the ground at night.

     The growing season at the airport ended on September 14 with a low of -1.0°C, about a week earlier than normal (Sep 22). This puts the length of the 2012 growing season at 106 days, shorter than the normal of 121 days. Of note however, this value for 2012 is a little misleading considering the ideal growing conditions seen this year due to a very warm Spring. By using the number of days between hard frosts instead (hard frost is defined as a night of -2°C and colder) we get a season of 148 days for 2012 (Apr 27 to Sep 21 inclusively). That is much more representative of the conditions experienced this year.

Snow in Kenora Sep 21
     The coldest weather of the month moved in a week later. Snowflakes fell in northwestern Ontario and areas north of Winnipeg on the 21st (video of snow in Kenora). Here in Winnipeg, heavy hail fell in some parts of the city midday with the passage of a cold front. Behind this disturbance, an arctic airmass under a ridge of high pressure allowed for record low temperatures on September 23. A low of -7.1°C was recorded at the Winnipeg airport, breaking the 133 year old record of -6.1°C back in 1879. It was also the coldest September night in 47 years (-7.2°C on Sep 26, 1965), the 5th coldest September night ever and the second earliest of its kind for the season. Even The Forks dipped to the freezing mark (0.0°C) marking the end of the growing season for dowtown, about 2 weeks earlier than normal (Oct 5).

     The cold spots were Dugald at -9°C and Emerson and Fisher Branch at -8.5°C. Some official record low temperatures across the province included:

     Despite such a chilly start to the day, temperatures skyrocketed through the day with daytime highs in the high teens, seasonal for that time of year. Winnipeg reached a high of 17.2°C, a 24 degree rise from what it was early that morning!

     In total, 7 days had a low below zero in Winnipeg, tying for third most subfreezing days on record for September. Click here for a graph demonstrating the frequency of days with a subfreezing low in September since 1872.

This post contains pictures, videos or information from the following sources

The Weather Network
Environment Canada Weatheroffice

Saturday, 22 December 2012

Forecast Going Into The Christmas Holidays

     Today, well, we have ended up in a cloudy and somewhat snowy day once again. Well, it was nice seeing the sun for a bit yesterday at least ;) We shouldn't see too much snow however, with maximum 1 cm locally. Generally it looks to just be a dusting. Our temperatures will remain in the high minus teens through the day. Tomorrow, well it looks to at least start cloudy. We are expected to clear for the afternoon, but we will have to wait and see considering how the past few days have gone.

     For now, the Christmas week looks clear and cold for the entirety of the week with no major snowfalls expected. There may be a few flurries here and there, but nothing too organised is expected at this point. Good news if you have lots of travelling to do for the holidays. Also, as far as how cold it will get, right now it doesn't look like -30°C nights are in the cards as this next push of arctic air is not expected to be as severely frigid as it could be. However, we may come close with lows in the mid to low minus twenties and highs barely over -20°C on some days.

     This will be my last post until at least the 28th as I'll be taking a break to spend more time with family and friends these holidays. If needed, I will still provide a few comments under this post until the 24th.

     Happy Holidays!

Friday, 21 December 2012

2012 Severe Thunderstorm Season Across Canada

     First off, this is a yearly post related to the Manitoba thunderstorm season summary which I posted early in the Fall here. Similarly, I have been keeping stats on the Canada severe thunderstorm season since 2010.
     Now in this particular post, I will summarize the SEVERE thunderstorm season across Canada. The stats I gather are of severe thunderstorm warnings and tornado warnings issued by Environment Canada. Everytime a warning of such sort is issued, I note down the day and place and gather all the stats at the end of the year. In addition, I also note all probable and confirmed tornadoes that actually touched down. There is a margin of error however. Sometimes, Environment Canada does make mistakes with issuing severe thunderstorm warnings. Some storms may actually be severe but have no warning on them; also the inverse sometimes occurs (a storm has a warning on it but never actually reached severe limits). However, there is nothing else I can personally do to eliminate this potential margin of error. Therefore, I content myself with just the warnings that EC does issue.
     Let's start with the length of the severe thunderstorm season per province in 2012, from west to east:

     The season began abnormally early in 2012 for the country as Ontario had their first bout of severe storms in mid March, 3 to 4 weeks earlier than in 2010 and 2011. Severe thunderstorms moved through the province on March 15, 17 and 18. Remarkably, even northern Ontario had severe thunderstorms on March 18. Tornado watches were even issued on March 15 in southwestern Ontario, due to the fact some tornadoes had touched down in Michigan. The exceptional warmth and humidity thanks to a jet stream that was much further north than usual was likely the culprit.

     The season was also longer in Saskatchewan and Alberta than it was in 2010 and 2011, starting a couple weeks earlier and ending a couple weeks later. 2012 also was Prince-Edward-Island's first severe thunderstorm in at least 3 years (there was none in 2010 and 2011).

     Now, as for the frequency of severe thunderstorm warnings per region in Canada in 2012, I have made a map for you all to make it easier to visualize which areas were most active:

     (Unfortunately, the way I have divided the country on this map is not perfect since the regions are not of equal size. I do plan to fix this problem in 2013.)

     With this map, it is easy to point out the most active regions; the western Prairies, northwestern Ontario and southeastern Québec. There are also other anomalies to point out however. Parts of southern Ontario were quieter than in the past 2 years, while BC was much more active. In fact, BC tripled the number of severe days seen in 2011 and saw 5 times more than in 2010.

     The biggest highlight however was the western Prairies. An unusually humid summer combined with a jet stream that was further north than usual brought frequent severe weather to Saskatchewan and Alberta. In Alberta, there was an amazing 54 days of severe thunderstorms throughout the year, 20-25 days more than in both 2010 and 2011.

     According to Environment Canada, it was the second busiest summer for severe thunderstorms in the Prairies since they've been keeping records in 1991. There were 371 severe thunderstorm events across the 3 Prairie provinces; Alberta saw a record number of 169 events while Saskatchewan saw its second highest number with 135 events. Of the 63 days between June 13 and August 14 only 11 days were free of severe weather.
     This year was also the second worst on record for hailstorms in the Prairies. In Alberta, it was a record year for crop losses. As for windstorms, it was also the second worst in the Prairies with 81 events of gusts of over 90 km/h. Again in Alberta, it was the worst year for windstorms with 41  events, breaking the old record of 37 events in 2007.
     Almost daily severe thunderstorms in Alberta in July brought serious flooding to some areas. The Edmonton region saw record rainfall for July. Stony Plain, a suburb west of Edmonton, received a total of 247.3 mm, the wettest July on record.

     Now, here's another map; this one showing the frequency of tornado warnings per region in Canada in 2012.

     Alberta and in particular Saskatchewan, saw numerous tornado warning events this season. Meanwhile, it was abnormally quiet for tornadoes in Manitoba and southwestern Ontario. Just 3 weak tornadoes were reported to Environment Canada in Manitoba, keeping in mind that none of these were actually confirmed. Saskatchewan however saw 33 tornado touchdowns, the highest amount ever in a single year for the province. Normally, Saskatchewan only sees about 13 tornadoes.

     Below is my last map; this one shows where all the probable and confirmed tornadoes occurred in Canada this season. This likely is an incomplete list; I don't have access to Environment Canada tornado reports. I use twitter, and media sources such as CTV, CBC and The weather network  for this data.

Inuvik, NWT tornado Jul 28
     The strongest confirmed tornado this season was an F2 near Storms Corner, Ontario on September 8. Unfortunately, Environment Canada has not, to my knowledge, rated all the tornadoes in western Canada. Only one F1 near Olds, Alberta on July 3 was confirmed.

     Notice that a tornado touched down all the way up near Inuvik, NWT. This occurred on July 28, and was certainly a surprise to those who saw it. Although it may seem unusual, tornadoes in NWT are not actually that rare. We just never hear about them, because most of the time no one ever sees them due to the low population density in the area. The strongest known tornado in the territory was an F2 wedge tornado in Yellowknife in 1978.

     The latest confirmed twister this year was a minor F0 near Mont-Laurier, Québec in the afternoon of October 31. It was one of the latest confirmed tornadoes on record. Some later confirmed tornadoes since the 1800's include: Nov 9, 2005 (Hamilton), Nov 16, 1989 (F2 near Mont-Saint-Hilaire, Québec), and Nov 1950 (Regina).

     And now to finish off, here's some links to some information on notable severe storm events this year:

1 - June 5/6 supercells in Alberta
2 - June 25 to 27 wicked thunderstorms in Saskatchewan
3 - Greg Johnson's collection of storm pictures 2012
4 - August 12 Calgary hailstorms
5 - July 23 eastern Ontario severe storms
6 - Hours of thunderstorms flood the Thunder Bay area in late May
7 - Montreal flooded after drenching thunderstorm May 29
8 - Heavy thunderstorms flood Edmonton early July 12

Some sources of the pictures and information I provided in this post:
The Weather Network
Environment Canada's Top 10 weather events of 2012

Friday, 14 December 2012

Snow Totals Past Few Days and Forecast

     A few rounds of snowfall brought some higher accumulations than expected to parts of southern Manitoba Wednesday and Thursday. Here are some snowfall totals for the two-day period: (note amounts come from reports to Rob's Blog, as well as Cocorahs therefore I don't have control over its accuracy)

Community Snowfall (cm)
Pinawa 15
Wpg Beach 14.5
NE of Portage 9.9
Woodlands 9.7
Morden 8.9
Morris 8.4
Emerson 8
Steinbach 7.2
Brandon 6.6

And in Winnipeg...
     Temperatures have warmed behind the snowfall with highs above normal today in the mid minus single digits. These milder temperatures will continue tomorrow with highs in the low minus single digits (-6 to -8°C). However, patchy fog, mist and freezing drizzle will be possible tonight and tomorrow before skies begin to brighten Sunday with the arrival of colder weather. Generally seasonal temperatures are expected to start next week, with a more organised snowfall possible mid-week (2-5 cm or so). At this point, below normal temperatures are expected after the snowfall, however no major cold outbreaks are expected in the near-future. I will provide updates in the comment section over the next few days.

UPDATE (5:30 PM) Dec 14: A special weather statement has been issued by Environment Canada for southwestern Manitoba and the western RRV regarding the likelihood of dense fog tonight. Watch out on the roads, especially highways if you have to venture out. Patchy freezing drizzle will be likely as well.

Saturday, 8 December 2012

Snow And Cold

     It is snowing quite steadily in parts of the city today as well as to our south. Amounts will vary within Winnipeg since the city is right on the line between the heavier snow to the south and lighter snow to the north. The south end will likely have about 5 to 8 cm by the afternoon while northern parts will likely only see 2 to 5 cm. Higher amounts of 10 cm will have fallen south of the city with possibly as high as 15 cm near the US Border by this evening.

     Behind this things will be quite cold for a few days with nighttime lows in the -20's and highs in the low to mid minus teens. Brr! No major warmup to be seen in the near-future. A brief warmup to the low minus single digits with chances for snow around Wednesday next week, but it is expected to be quite brief.

Wednesday, 5 December 2012

Messy End to the Day Possible

     It may seem nice out there with the sunshine right now, but it could be a different story this evening. In addition, winds will be quite strong this afternoon with gusts to 70 km/h.

     It will be mild with highs approaching 0°C, especially this evening. A low pressure moving into central Manitoba, which will be giving central and northern Manitoba another blast of snowfall (10 to 20 cm), will also bring southern Manitoba some messy conditions this evening. Freezing rain is possible in all of southern Manitoba, therefore freezing rain warnings have been issued by Environment Canada for all of southern Manitoba except the Melita and Virden regions. Some areas may see a mm or two, while some may get just a couple sprinkles. It is hard to say right now since the area of precipitation hasn't formed yet. In addition, it is possible that the precipitation may fall as ice pellets instead.

     Nonotheless, it will likely be a messy evening.

     Cold weather will dominate the rest of the week into the weekend.

UPDATE: Here's a good article about the snowfall in northern Manitoba early this week. Up to 90 cm of snow fell in the Norway House-Island Lakes region in 24 hours, possibly making it the heaviest 24 hour snowfall on record in Manitoba. It's hard to confirm this due to the fact that the snowfall amounts are not official.

Tuesday, 4 December 2012

Fall 2012

Fall stats (Sep-Oct-Nov). CLICK to enlarge
     This Fall was a bit of a transition period; going from more than a year of warmer than normal months to colder than normal weather. It was the first colder than normal season since the Spring of 2011. With an average mean temperature of 3.5°C, it was also the coldest Fall in a decade, going back to 2002 when the average mean was 2.6°C.

     There were certainly a few notable cold events. A low of -25.5°C in late November was the coldest November low since 2007. In addition, the high temperature was a measly 4.9°C making it the coldest November maximum in almost two decades, going back to 1995. It was the first colder than normal November since 2003.

     October featured some early snowfall as a major Colorado Low dumped up to 30 cm on the 4th and 5th over southeastern Manitoba. It cut power to thousands. Winnipeg dodged the worst with just a couple cm, but it was the earliest accumulative snowfall since 1996.

Sep 30... 24°C
     September was near normal on average, but that does not tell the whole story. With 7 nights of freezing temperatures (below 0°C), it was the most in 3 decades, since 1984, and tied for 3rd most. A low of -7.1°C on the 23rd was the coldest in September in half a century, and the 5th coldest on record for the month. September wasn't all that bad however. There were brief glimpses of summer as temperatures on a few occasions approached 30°C. This included the last 2 days of the month, which featured near record-warmth. The heat coincided with the change of colours of the leaves making for a wonderful end to the month.

     As for precipitation, Fall also marked a transition period. October marked the first wetter than normal month since May, thanks to significant rainfall. The rain in October was much welcomed after the second driest September on record with just 4 mm of rainfall.

     November continued the new trend with snowier than normal weather; about 40 cm of the white stuff. This was mainly due to a significant snowstorm on the 10th and 11th which dumped between 20 and 25 cm over Winnipeg, with higher amounts to the west and north, as high as 65 cm in Mafeking and 37 cm in Portage.

Monday, 3 December 2012

Roller Coaster Ride

     A clipper system moving into central Manitoba brought quite a roller coaster ride to southern Manitoba today. The day started very mild with temperatures of 2 or 3°C. The system brought a brief band of steady rain to much of southern Manitoba this morning, dropping a good 1 to 3 mm in general. This is quite unusual for this time of year, and is the most rain in December since 2005.
     The system brought exceptional snowfall to central Manitoba today with 45 cm measured at Norway House and 20 cm in Mafeking (Mafeking is the town that saw 65 cm of snowfall on Nov 10). It's turning out to be a brutal winter in central Manitoba!

     Temperatures plummeted this afternoon and winds increased. Everything has frozen up, and snow and blowing snow have begun. It looks like these periods of snow and blowing snow will continue for the majority of the evening before things push out overnight. Temperatures which have fallen to near -10°C now will begin to stabilize with lows tonight in the high minus teens.

     Tomorrow will be cool with highs barely reaching -10°C. However, the cool down will be brief, as we go back up the roller coaster Wednesday with rising temperatures overnight through the day into the evening. We may get close to the freezing mark again. Again it will be brief as temperatures cool late week with the potential for some flurries Thursday.

     Beyond that things are uncertain right now as the stormy pattern continues into early next week when a more significant cool down will be possible.

Saturday, 1 December 2012

November 2012, Cold And Snowy

November 2012 stats, CLICK to enlarge
     November 2012 ended colder than normal, which is something that is long overdue. It marked the end of a streak of warmer than normal Novembers going back to 2003, our last colder than normal November, 9 years ago. The monthly high temperature was a measly 4.9°C, the lowest November maximum since 1995.

     Snowfall was another highlight with 40 cm of snowfall through the month, almost double the normal. This high amount was mainly due to a significant Colorado Low on Nov 10-11, and from multiple back-to-back clipper systems late month.

     The Colorado Low on Nov 10-11 was very significant. 20 to 30 cm of snowfall fell over the city, making it the most significant snowstorm since late December 2006. What is important to note however is how fast the snow came down. 10 to 15 cm of that fell in just a few hours in the evening of Nov 10 under blinding heavy snowfall. Even heavier amounts fell to the northwest of the city, with 37 cm in Portage, 40 to 60 cm in parts of the Interlake and 65 cm in Mafeking (western Manitoba).

     Other than that, gloomy skies were the trend of November. The month started cloudy or mostly cloudy day after day. The first mainly clear day was not until Nov 14, after almost a month of day after day of cloudy or mostly cloudy skies.