After a wet and near normal temperature October, the first in months, November fell back into the same old pattern since last year; above average warmth and below average moisture. Looks like Ottawa will close out the month around 7.5c average temperature (normal is 5.4c) and only half the months normal precipitation at 42.2 mm (normal is 81.9mm). Most of Southern Ontario has similar stats.
Another two or three days of above normal temperatures before we head closer to normal on Sunday Dec.5, actually below normal for those first couple days of the week. However in classic ugly GLC style, another storm from Colorado heads to Ontario and cuts across Lake Superior again around December 7 – 9th. This one looks stronger then the last couple, and perhaps has some snow on the backside of the storm as it moves through (backside meaning the western side of the low pressure system as it advances and pulls Arctic air behind it). Backend storms rarely bring big totals because the ground is warm and wet from the first part of the storm that was rainy, but it can surprise once and awhile. What will be interesting is the storm looks strong with lots of wind and should leave Lake Effect Snow (LES) behind in the typical areas around Georgian Bay and Lake Huron (Bracebridge, Barrie, Collingwood, Alliston, London etc).
Here is a look from the GFS model at this early point, BTW, all models are showing a similar size storm in a similar location:
Thursday morning:Late Thursday Night:
What the storm does bring is more rain to areas that need the moisture before winter, and it helps break the pattern, bringing the cold Arctic air I have been talking about for mid month. Watch for temperatures in the days behind the storm struggle to stay near -2c during the day. This should get lakes to start the freeze cycle and get some frost in the ground.
At this point I am not seeing any significant snow on the ground possibilities until after Dec.10th, so non-winter lovers can be happy for another week or so.
I am getting slightly concerned that this pattern is here to stay for the month as we have upper atmosphere conditions and blocking ridges in the south supporting storms to continue to track west across the lake like this. The long range shows another similar storm around Dec.16th…
This could get tricky to maintain snow on the ground if you are hoping for a white Christmas. Long range storms are very hard to predict so don’t write it off just yet 😉
I will start providing a White Christmas outlook this weekend and keep it updated weekly.