Friday, September 14, 2012

2012 growing season ends with frost over much of southern MB..

7 am temperatures - southern MB
Sept 14 2012
Temperatures dropped below freezing across much of southern Manitoba early this morning, including at the Winnipeg airport with a low of -1.0C.  This marks the end of the official growing season for 2012 (as measured at YWG airport), which lasted 106 days since the last spring frost on May 30th (low of -0.1C). This is actually a bit shorter than normal for Winnipeg's average growing season, which generally runs 121 days between the average last spring frost of May 23nd and the first fall frost of  Sept 22nd.   However, this year's growing season length is a bit misleading. There were only 2 days of light frost in May, with low of -0.7C on the 16th and -0.1C on the 30th. The last hard freeze (temperature below -2C) was back on April 26th with a low of -7.0C.  Using this date gives a growing season length of 140 days, which is more representative of the ideal conditions experienced this year. Farmers were able to get in a crop much earlier than usual thanks to a record warm March, with warm conditions persisting through the summer along with adequate rainfall. The result was a record crop for many across southern Manitoba this year.  

And although frost was fairly widespread over the RRV this morning, downtown Winnipeg escaped frost with a low of only +5.0C at the Forks. Downtown Winnipeg has a much longer growing season than the airport, due to the urban heat island effect that keeps night time temperatures warmer than areas near and outside the perimeter. The average first fall frost downtown is Oct 5th, while the last spring frost is May 4th giving an average growing season of 159 days downtown, or 38 days longer than the airport (121 days). For most areas of the city, the length of the growing season lies somewhere between downtown and airport values. At my site in Charleswood, a low of +0.1C was recorded with some light frost.

13 comments:

  1. Nice summer like day out there today with upper 20s over RRV, and even a couple of 30c readings over western RRV from Elm Creek through Carman down towards Morden/Winkler area. Winds have shifted into the NW just west of Winnipeg with temps a little cooler in the mid 20s. Enjoy it.. This may be our last taste of upper 20s until next spring! (although I'm hoping we see a couple more later this month into October)

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  2. I saw this article from WxRisk about the El-Nino or lack thereof so far.

    http://www.wxrisk.com/2012/09/spock-where-is-that-damn-el-nino/

    Idea is that true El-Nino conditions are having a hard time sustaining themselves. Typical El Nino's bring wet fall conditions to the northern plains according to local FGF research but this doesnt appear to be case so far and signs are continued dryness.

    What this means for winter? I dont know. Our local climate expert who writes local tidbits for us foreasters is suggesting a weak El-Nino, with other factors moderating its impact. Overall he expect normal temps/normal snowfall. CPC outlooks are almost always El_nino or La nina based and thus its warm and dry winter may be in trouble.

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  3. Certainly for farmer's sake next spring...we hope we can get a good snowpack with water in it....

    Last winter was a poor one for this soul :)

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  4. So we hit 28C after all (plus a bit).

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  5. Eww at the forecast. Looks like it time for me to start stocking up for hibernation

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  6. Oh my, The Weather Network calling or snow-showers tomorrow night.

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  7. Thanks for the info Dan. Tough to get an accurate read on what will happen with el niño as it's in a transition stage. I see CPC is calling for a weak el niño through the end of the year, which would give a better chance for a colder and snowier winter for us than with a strong el nino, provided other influences don't work against it (like a +AO signal like last year). I still think winter will be delayed this year given the record low arctic sea ice, and the trends of the past decade. But after last winter, I have given up trying to predict what our winter will be like.. too many variables and unpredictable influences to have any reasonable skill. But I commend those who try! No doubt though, for storm lovers, the past year has been a bust for us, both in terms of winter and summer events.

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  8. Ah, rounded high was 29C yesterday. NAM was closest I believe. Frost overnight, 29C in the afternoon! Desert weather.

    I also appreciate and pity anyone who attempts seasonal (even monthly) forecasts. So many variables, so many of them unknown, so often wrong. It must be disheartening but I'm glad they keep on trying.

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  9. Rob had commented about the WMO dropping the previous world record high temp at Al Azizia, at least partially due to observer error. I checked out the wunderground blog entry about it, and it totally makes sense. Unfortunately, similar issues affecting our climate data are still occurring nearly 100 years later.

    Anyone who has worked as a contract aviation weather observer likely knows what I'm talking about. Hiring people who got fired from McDonald's (literally) isn't the best idea, especially when aviation safety is also involved. I saw so many wrong obs being taken as truth, simply because they were entered correctly on the sheet. Automation may actually be an improvement, but as we are seeing even in Winnipeg that also has repercussions.

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  10. Goodness, wonder if any flurries are coming out of those showers to the west with these types of temperatures.

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  11. Quite the temperature difference between the airport and the rest of Winnipeg last night. Down to -2C at the airport, but only +3C at my place in Charleswood, and +4.6C at the Forks. Most places within the perimeter didn't drop below freezing last night, with a light NW flow allowing some subfreezing temps NW of the city to drain into the airport site. A good example of how the airport is sometimes not representative of the majority of the city.

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  12. and a whopping 9 C at Victoria Beach! Truly the Banana Belt of Manitoba.

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