Wednesday, December 21, 2011

Staying mild and storm free through Christmas..

The above normal temperatures and tranquil weather of December is forecast to continue through the upcoming Christmas holiday weekend, with little in the way of major weather systems to disrupt holiday travel plans across southern MB. Temperatures are expected to remain 5 to 10 degrees above normal through early next week as mild Pacific airmasses periodically sweep across the Prairies keeping cold Arctic intrusions at bay. In fact, above freezing temperatures are forecast for Christmas Day into Boxing Day as another push of Pacific air sweeps in over the holidays. This will likely mean a brown Christmas for portions of southern MB this year, especially towards the US border into North Dakota (see webcam page). For Winnipeg, we will likely end up with whatever we have now.. a meager coating of about 2 or 3 cm with no significant snowfall expected between now and Christmas. The longer range outlook calls for above normal temperatures to continue through the end of December, with no signs yet of a major pattern shift to colder and snowier weather over the southern Prairies. For you snowlovers out there, have faith though.. technically, winter is just starting! (winter solstice arrives tonight at 11:30 pm CST)

14 comments:

  1. Rob, If things keep going in this direction and stay like this all winter, what are the chances of seeing more precipitation than normal during this spring? does the soil moisture have anything to do with the precipitation we get?

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  2. Environment Canada has just released their top 10 weather Stories of the year. Check them out on EC's website!

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  3. Mike.. soil moisture plays a key role in driving summertime (convective) precipitation.. but it is not really a factor in the spring when the soil moisture is still frozen in the ground. I doubt there's any correlation between wintertime snowfall and springtime precipitation.

    Springtime precipitation is mainly driven by larger scale storm systems (synoptic scale) which are dependent on the overall position of the jet stream (storm track) tied to hemispheric and global scale weather patterns.

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  4. Jeff Masters has a good blog post taking a look at the difference between this winter and last.. and how this year's flip in the Arctic Oscillation is contributing to our delayed start to winter. (click on my name for link) Seems that the AO has a more direct impact on our winter temperatures than the ENSO.

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  5. Further to the link above, here's an interesting image at the type of winter we can expect when looking at the combination of AO and ENSO phases. (in other words, what does a +ve AO do to a -ENSO?) Click on my name for image from NCEP. The image clearly shows that a +AO trumps a -ENSO (La Nina) and gives us warmer winters, while a -AO gives us a better chance of a cold winter. Then there's Dan's worst nightmare.. +AO with +ENSO! :)

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  6. Great links Dan, Rob and Adam and Mike
    A few years ago I came across a chart of 20th Century years grouped by ENSO (Nino, Nina, and Neutral, and the PDO and AO influences (+ -)
    Perhaps linked from Jeff or NOAA. It was sometimes helpful to predict winter weather and precip.
    If you have the link please post it?

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  7. Hello,

    I noticed on AccuWeather's website for Dec 29-31 they are calling for 20 cm of snow. Is this possible? Could it actually happen? Sorry, really hoping for snow and lots of it.

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  8. Thanks for the info rob! Have A Merry Christmas!

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  9. Hi Mark, answering your question I looked at the ECMWF snowfall model, it looks like we could receive some snow on the days 29-31 but we may not get a whole lot. At the most we may see 2cm of snow, if you want u can click my name for a link to the model its on wunderground. Just click model data and then model type to see snowfall. Have a Look!

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  10. Hi Mike,

    Thanks for the link. Never seen this site before.Using the ECMWF model, advancing the forecast hours ahead 180 hrs, and using the map type snowfall I see what you are saying.
    (I think I did this right)

    How many different snow models are there? Why does accuweather predict that much snow? Do they use different models?

    thanks!

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  11. Hi again Mark, Answering your question there really isn't any other snowfall models on wunderground, but if you are interested you can check out the precipitation type forecast on every one of the models. And about accuweather sometimes they follow their own guidance data from their computer systems so they may have a different outlook on things than what we have on wunderground. It is also quite far ahead to tell what the weather will be like on the 29th as the weather models tend to change over time, as the day gets closer we will be able to tell what the weather will exactly bring. So 20 cm sounds a little to significant for this time around. Anyways, you might have to ask rob about what Accuweather uses for weather models as I am still an amature at weather forecasting, oh by the I wish you a merry christmas!

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  12. Thanks Mike,

    Have yourself a Merry Christmas as well.

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  13. Just letting all of you know that I will be posting a article on Winnipeg's weather of 2011 In statistic form for each season an example would the number of days we had windchill values. I should have it up by sometime this week towards next week, I have a lot to research. I hope you all look forward to it! till then Happy Holidays!

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  14. Looking forward to what 2012 brings in the weather department.

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