Monday, November 01, 2010

Late October rain gives Winnipeg wettest April-October period on record..

October was a mild and dry month until an intense fall storm brought heavy rain, snow and colder temperatures to finish off the month. The month was very quiet through the first 3 1/2 weeks with only 1.3 mm of rain on 2 days during that stretch. The dry weather was very much needed after an exceptionally wet August and September that left soil conditions saturated. That dry weather came to an end however on the 25th-27th when an intense storm system passing through Minnesota brought heavy rains of 50-90 mm through the Red River valley and snow (5-30 cm) over western MB. At 955 mb, the storm system was the deepest low ever recorded over the central continent, and produced the lowest pressure on record at Winnipeg (967 mb) The late month deluge led to yet another month with above normal precipitation in Winnipeg, helping to produce the wettest April-October period on record since records began in 1872 (630 mm, old record 625 mm 1977) The season's first snowfall in the city came on the evening of the 29th when 1 cm of snow was recorded, with heavier amounts of 3-5 cm over the northern part of the city.

Temperatures in October were very mild with daily highs above 10C through the 26th, including an 8 day stretch of 20C plus weather from the 4th to 11th, the longest 20C stretch in an October since 1963 (11 days) and tied for the 2nd longest streak on record. The month was on pace for a top 10 finish for mildest Octobers through the 26th, however cooler weather over the last 5 days of the month knocked it out of top 10 honours. Nevertheless, the month finished with an average of 8C at Winnipeg airport, almost 3C above normal.

All in all.. a much needed dry and mild month with a wet and cool finish.


  1. Rob!

    Any indications of how November might play out???

    Snowy month or dry???
    Warmer or colder than average???

  2. Looks dry and mild through this weekend.. then signs of a storm system passing through the northern Plains/southern MB by the middle of next week with rain/snow. Trending colder after that but still too much uncertainty about how the rest of the month will play out concerning temperatures and precipitation.

    Note that in the past 10 years, the majority of our Novembers have been dry and mild.. possibly in response to warmer Arctic ocean temperatures that help delay the onset of cold Arctic air over the Prairies. This year is seeing yet another abnormally mild fall over the Arctic with slower than normal ice growth.. hopefully that means another year with a delayed start to winter.. (sorry Dan :)

  3. That's good news as October 2010 similarities to Oct 1995 were ominous. They include
    Mean temp 4.7, (8.2)
    Precip 41.6mms, (48.0)
    and a monthly concurrent slide from El Nino to La Nina.

    On Nov 12th 1995 it was a cool -26.9. with a mean min Nov temp -14.6. This was followed by Extreme Dec to Apr96 Monthly lows of -37.0,-39.4.-41.8,-33.7,-22.9.. which for some, might make an ideal winter!!

    That cold Nov/winter followed a 1995 ice melt of over 2 million sq. miles. It was first time the loss exceeded the 1979-2008 average (loss) by over 1 million sq mi. Click on my Name or see below

    I for one, am glad this year isn't a repeat.

  4. There are a number of Acronyms used in the forecasts given here and on the medium and long term outlooks CPC SPC GEM

    Is there one site or source you would recommend that define these? Book? URL?

  5. Those acronyms come from various sources, so there probably isn't a single site or book that would define all of them. The ones you mention: CPC, SPC are the Climate Prediction Center and Storm Prediction Center. Whereas others like GEM, GFS, NAM, WRF, ECMWF, etc are the names of weather models.

    The best source for you is probably the Glossary on the NOAA site. It won't have all of the terms, but it should have most of them.

  6. Rob!

    Looks like a system could be in the area next week giving some areas a chance of accumulating snow! ( maybe western Manitoba)???

    Better enjoy this nice weekend cause you never know when things could take a turn for the worse!