Tuesday, December 02, 2008

EC releases winter outlook for 2008/09

EC has issued its winter outlook for the upcoming 3 month period of December through February. The outlook, produced from a consensus of 4 climate models ingesting 3 weeks of current weather conditions and extrapolating into the future, indicates warmer than normal conditions this winter over the East Coast (mainly Newfoundland and Nova Scotia) while colder than normal conditions are forecast from northern Quebec through Hudson Bay and northern MB into NWT and the Yukon. Over southern MB, there are equal chances of a "normal" or below normal winter with a lower probability of a mild winter. Across the rest of the country, model consensus does not point to any specific outcome, with generally equal chances of above, near or below normal conditions (i.e. a non-forecast)

EC's 3 month outlook is available on EC's Weatheroffice website at this site. NOTE: For monthly and seasonal outlooks, I highly recommend you look at the probabilistic outlook map rather than the deterministic outlook map. The deterministic maps do not accurately reflect the true output of the climate models, which is better reflected by the more informative probabilistic maps. The probabilistic maps more accurately indicate where the climate models are showing the best agreement for above or below normal conditions occurring, and where there is the most disagreement. This measure of uncertainty is not indicated on the deterministic maps which make them subject to greater misinterpretation.


  1. Wow
    -19 C for a daytime high on Saturday!
    Now that is cold for this time of year.

  2. Despite winds staying up all nite with decent mixing.. drainage effect kicked in again at YWG. In fact as soon as winds shifted from the NNW to WNW temps plunged 4 degrees to -17C. Please EC move the official weather station somewhere else. The wonky values coming from there cannot be used to derive climate statistics etc.

    As for -19 C on Saturday... once again I believe EC guidance is too cold. It will be a cold set up to be sure with an arctic high dropping SE. But with 850 MB of -18 C and minimal snow cover... modification of surface temps may occur.

  3. I will have a respectful disagreement with Daniel on the high for Saturday. It is December, and now that most areas have at least a thin layer of snow I wouldn't be at all surprised to see temperatures struggle above -20. I would probably suggest the high will be -19 for Winnipeg, and a couple degrees warmer farther South-East where there is less snow cover.

    Next week the models are showing snow and extreme cold. Two major snowfall events producing 10 to 15cm each time are forecast next week. Because the models indicate that snowfall the ground will be good and covered. This allows me to reassert my prediction that we may be in for -30 to -35 lows next week. At this point -40 appears possible, but very unlikely. The best bet would be for low -30's (assuming we do get that snow next week).

  4. I hope the models are correct!
    Yes I see that on Monday and also Wednesday the GFS is showing some heavy snow events.
    OH BOY!!!!

  5. Ya hoo....I hope you guys are right. We need snow.....big snow.....

  6. I see Environment Canada has to revise there overnight low!
    I guess they underestimated the cold air mass.
    I think Scott is right!
    The air mass coming in is extremely cold and I also believe that temperature could just be as cold or COLDER that what Environment Canada is calling for all week!

    I guess that small snow pack is not having that great of an effect on raising the temps.

  7. YWG is sitting at an absurd -18 C right now. The cold spot in S Manitoba. Open country sites off to the NW at Rosser and Grosse Isle sitting @ -15 C.

    The only reason for revising the low downwards is for the drainage effect around the recording station. It is just an artifact/idiosyncrasy of that site. Maybe one day EC will move the recording station ...maybe.

  8. I still see the potential for frigid temperatures next week. The potential for widespread lows of -30 to -35 is very real. I doubt -40 will be realized in Southern Manitoba. However if we see the combination of more snow than expected along with a stronger than expected high pressure system it will be possible.

    Saturday's much debated forecast looks to fall through anyway. The WRF indicates a high in the -4 to -8 range, along with a low of -14 to -18 in the evening as a Northerly wind kicks in (maybe colder in Winnipeg with the pesky North-West drainage!)

  9. Question for Rob..

    What time frame does EC use for its high/low temperatures? Is it simply the highest and lowest temperatures of the day, or low in the morning or evening. This doesn't really matter for the day one forecast, because you give a "tonight" outlook, but how about for day four as an example?

  10. The GFS this morning is showing some VERY VERY cold air in here by next week!
    Again overnight lows in the -30 are very realistic if the models verify!

  11. Yep.. next week's looking awfully cold. Big Yukon high dropping southward bringing -25 to -35 air with it.. Yikes. Make sure you have that block heater ready!

  12. Scott..

    In the Day 3 to 5 forecast, the high temperature specified is between 6 am to 9 pm, while the low temperature is taken from 8 pm of the previous evening to 10 am of that day.

    Generally, these temperature "windows" work OK if the temperature follows a typical diurnal trend with the lowest temperature first thing in the morning, and a high temperature in the afternoon. However during the winter, the actual high and low temperatures for the day can sometimes fall outside these defined windows. For example, many times in the winter you can have a falling temperature trend during the day. In these cases, the low temperature will not be properly reflected in the Day 3-5 forecast since the cutoff is at 10 am, and the temperature is falling through the day into the evening. In these cases, the forecast high and low temperatures will often be close to each other or even the same.. a clue that an abnormal temperature trend is likely that day.

  13. The wind is a fairly strong today!
    It is approaching 30 km/h as of noon!
    Which is in turn is keeping the windchills quite low all day!

    Maybe we will be picking up a couple centimeters of snow tomorrow with the passage of the Alberta Clipper!