Monday 30 December 2013

#10, #9 and #8 - Top 10 Weather Stories of 2013 in The Winnipeg Area

#10 - A return to reality; a colder and very snowy winter

 

     After experiencing the 4th warmest winter on record a year earlier, the winter of 2012/2013 was a bit of a shock.

Credit: CLIFF BEBBER in January 2013 (sent in to TWN)
     The second half of January and the first few days of February featured the coldest weather in 2 years. 8 days saw temperatures dip below -30°C, the first -30°C readings since February 2011. A low of -33.1°C on January 20 ended a 694-day streak without reaching -30°C, the second longest streak of its kind since 1872. The longest was a 714 day-streak from February 15, 1930 to January 29, 1932.

     After reaching a balmy 2.6°C on January 10, Winnipeggers did not see above freezing temperatures until March 28. This 76-day streak without reaching the freezing mark was the 20th longest since 1872. Longest was a 108-day streak from November 9, 1996 to February 24, 1997. A list of the longest streaks can be seen here.

     The snow was the biggest story of the winter. From November to March, only February saw below normal snowfall. March saw more than double the normal snowfall with 36.4 cm, 22nd snowiest. Both January 2013 and November 2012 were 20th snowiest. By the end of January, Winnipeg had already received an entire year's worth of snowfall (since October). By the end of March, 160.2 cm had fallen since October 1, the 13th snowiest Oct 1 to Mar 31 period since 1872. A list of snowiest Oct 1 to Mar 31 periods can be seen here.

     The high snowfall totals created one of the deepest snow packs in years across southern Manitoba. A depth of 58 cm in Winnipeg on March 18 was the deepest snow pack since the great blizzard of April 1997. Snowbanks were massive, making it difficult to move around.

#9 - Mid-summer blues


Early August, persistent northwest flow. CLICK to enlarge
     After a hot start to July, summer appeared to be over by the second half of the month. An extended period of fall-like conditions settled in at a time when we are typically at our hottest. This was thanks to the jet stream which featured a deep trough in northern Ontario and a large ridge in western Canada. This maintained a chilly and consistent north/northwest flow over Manitoba which lasted for almost a full month.

     27 consecutive days saw below normal temperatures from July 19 to August 14. In this period, highs averaged 22.3°C and lows 8.7°C, both some 4 degrees below normal for the period. The maximum temperature was a measly 25.2°C, startling when you consider the fact that normal highs in the period are 25 to 27°C. 4 days didn't even reach 20°C, while a total of 20 days saw morning lows in the single digits. Many nights saw lows flirting with record lows. On many occasions it got down to between 2 and 5°C across southern Manitoba, 7-10°C below normal.

     Winnipeg reached a record low on July 27, dipping to 5.6°C. That broke the old record of 5.8°C in 1978. A full list of records broken on this day can be seen here.

#8 - Twin May rainstorms


     Two major Colorado Lows in the second half of May dumped excessive amounts of rainfall in the Red River Valley.

Radar image was from The Weather Network. CLICK to enlarge
     The first system was, of course, during the May long weekend. Showers and ongoing cloud cover lasted for 5 days from Friday the 17th to Tuesday the 21st. The heaviest of the rains fell on the 19th and 20th. Consistent and strong east/northeast winds caused significant upsloping along the escarpment producing magnificent rain totals in the southwestern RRV. Locally 100-200 mm of rain fell west and northwest of Morden, while 50-100 mm fell elsewhere in the southwestern RRV including over 90 mm in Morden. Overland flooding and overflowing streams were a major concern. Basement flooding, road closures and flooded farm fields were some of the unfortunate consequences. Overland flooding onto the highway forced the closure of the US border at Gretna. South of the border, 200+ mm of rain near Walhalla, ND caused the evacuation of Cavalier, ND due to a potential failure of the dam to the west. Thankfully, the dam did not fail in the end.

     Winnipeg was spared the worst with ''just'' 15-50 mm of rain. Southern sections saw 30-50 mm while northern and central parts saw 15-30 mm. Winds were the main concern, with gusts up to 80 km/h on the 20th.

May 30 model forecast showing moisture streaming north
     Another slow-moving Colorado Low on May 30-31 brought a repeat performance. Once again, consistent and strong east/northeast winds of 30-40 km/h gusting to 50-60 km/h created significant upsloping along the escarpment. In just 2 days, 70-120 mm of rain fell in the southwestern and western RRV including 75 mm in Morden. Overland flooding and bursting streams were once again a concern. About a dozen highways across southern Manitoba closed due to washouts, flooding or poor driving conditions due to mud. A creek that flows through Morden burst its banks and flooded neighbourhoods for the second time. In Winnipeg, a general 35-50 mm of rain fell. Traffic lights at some intersections were knocked out creating traffic issues.

     In total, a general 150-250 mm of rain fell in the southwestern RRV throughout May, which is around half the annual normal! Click here for a map of rain totals in May across southern Manitoba.

8 comments:

  1. Low of -35.7°C at Winnipeg airport this morning. Tonight will be mighty interesting with the potential for -40°C lows. Potential is there to break a record in Winnipeg. RAP weather model dipping Winnipeg down to at least -41°C so the possibility is there.

    My personal forecast low is -39°C. If anyone has their guesses, feel free to share!

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  2. Well, temps not plummeting like I thought they would have already at YWG Airport. Just barely - 30C as of 8:30. Suddenly looking like - 40C is becoming a stretch for tonight especially with that light Southerly flow currently observed at the Airport. We'll see what happens.

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    1. Not entirely unexpected. Southerly winds are expected to become more northwesterly overnight. We'll see what that does. I'm still anticipating lows around -38°C to -39°C tonight, but likely not until early morning.

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  3. Low as of 6am was -37.3°C at Winnipeg airport and -38.7°C at Brandon airport. Will have a list of official lows this afternoon.

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  4. Looks like this December will end up 6th coldest on record since 1872. I plan to have a December summary tomorrow.

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  5. Great job on the last 3 top ten weather events of 2013! I totally agree with the order. It must be a lot of work writing them all and choosing them, I could never do it!

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  6. Official low in Winnipeg this morning -37.9°C, just off the old record of -38.3°C.

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