The disruptive weather we're tracking for first weekend of 2015

Monday, December 29, 2014, 12:00 PM -

Our forecast team remains focused on the possibility of a storm threat for parts of Central and Eastern Canada and the Eastern U.S. this weekend as a weather system that will give snowfall to parts of Southern California and the desert southwest (possibly even Las Vegas) will move east.

What is unquestionable is that the coldest air of the season so far is flooding across the country as an Arctic surge pushes from west to east. This guarantees lake-effect snow and some nasty driving conditions across the snow belts of Ontario during the next few days.

And regardless of whether this weekend’s storm threat materializes for your area, the weather pattern is set for winter mischief over the next two weeks and it’s likely that most areas with green grass will have snow cover by the middle of next week.

Forecasters pulling hair out. New GFS brings pot'l storm back north. GFS upgrade still south. Model mayhem #onstorm pic.twitter.com/AYQjfGNiHo

— Chris Scott (@ChrisScottWx) December 29, 2014

Here is the latest:

• Since Sunday, many computer models have shifted south with the storm track and are slower moving the system east
• As a result, if you live in southern Ontario or Quebec, you may not be seeing much precipitation in your weekend forecast as we were originally concerned about.
• There is still a lot of uncertainty with the weekend forecast and some data that still suggests a significant winter storm is possible

The value in this information is the “heads-up.” This is especially valuable if you’re travelling long distances or have outdoor activity intentions. Given this type of jet-stream setup, there is a greater degree of uncertainty than normal in the five-to-eight-day forecast window and we may not have the weekend weather details pinned down until about Wednesday.

What I do with this type of information is put it in the back of my head, and refresh it a couple times a day to see if the forecast is trending one way or another.

This is where the probabilities of weather prediction have to be squared with our lives lived in Yes/No decisions. We deal with probability all the time in daily life without realizing it. For example: You may not you exact weekend plans. You have a few options, and will decide once you get closer. That’s how to look at this weekend’s forecast. There are a number of possible outcomes ranging from no impact whatsoever on your plans to a significant impact. That’s the reality of the current weather setup and the limitations of meteorology.