It's a New Year and a New Pattern | Weather
This past month of December started much as last December did in Rochester, warm and snow-free. But that changed midway through the month as a new hemispheric jet stream pattern emerged. (The potential of this happening was something we addressed in detail during our winter weather special back in November.)
The new pattern resulted in the greatest national Christmas morning snow cover in a decade, with three times as much of the country covered in Christmas snow than was observed last year. And as of January 1, the U.S. snow cover stood at 67 percent. Last year at the same time, only 20 percent of the country had snow cover.
While this past December was about as warm locally as last December, this new pattern brought snow aplenty. Officially there was 23 inches of snow at the airport compared to 5 inches in the previous December. And the airport numbers were clearly on the low end of area snowfall tallies with most Monroe County communities receiving between 25 and 35 inches of snow. The depth of snow reached 18 inches in some areas. Skiers, sledders and snowmobilers rejoiced.
And after a mid month pause, there will likely be more rejoicing in the weeks to come.
Looking ahead, there will be a “relaxation” in the cold pattern here later next week (week of January 7) into the following week (week of January 14). It will even turn fairly mild for a few days. Meanwhile, future arctic assaults will be directed toward the central and western states, this as an upper air trough (a reservoir of cold air) shifts across the country from east to west.
As we move into late January and February, we expect the prevailing jet stream pattern to feature the trough returning to the central and eastern states, which would facilitate the arrival of arctic air masses here.
This pattern should result in additional snowfall of some import, thus we see no reason to deviate from our November prediction of a “normal” winter snowfall here, in the neighborhood of 100 inches.
At this time, we are not expecting extremely cold and snowy conditions over an extended period of time, though it would not be a total shock if for a week or ten days in February it turned mighty cold and snowy. But given input from one of our more reliable long range forecast models, I don’t see signs of the kind of brutal conditions coming here that have been observed in eastern Europe and Russia.
Happy New Year to all.