Whether we're all doing Bing Crosby imitations on Sunday evening and Monday morning comes down to a matter of melting.
Three weeks ago, extended-range ensembles of models had good agreement between one another of a prolonged period of below-average temperatures and hints of multiple lake-effect events within that pattern. All that has been realized, with the lake-effect hitting some parts of Western New York and missing others. That’s usually the case.
But what couldn’t be foreseen last month was a weeklong break in which temperatures would spike up to melt-worthy levels for several days, with a shot of rain to boot embedded in the temporary warmup. For those who desire a traditional White Christmas, the timing for this warming and wetting couldn’t be worse.
Western New York has had favorable climatology for White Christmases over the years. Buffalo has higher probabilities than nearly all cities with a population of 250,000 and up.
Combining that climatology with the coming cold pattern, it seemed reasonable for me to project somewhat-better-than-the-already-favorable average probabilities for a White Christmas this year late in November. As of Dec. 19, the month has been 2.8 degrees colder than average, with Buffalo’s snowfall for the month just shy of 20 inches, which was, as of this writing, 5.6 inches above average. This surplus developed despite the airport observatory's having been mainly bypassed by the Snow Bowl lake-effect storm.
Now we find ourselves in this temporary thaw, with Pacific air flooding in to replace the arctic air that kept us below freezing from Dec. 9 through Dec. 17.
All that truly frigid air will be bottled up well north of us most of the time until Christmas Eve. The European model recognizes the arctic air deficit and had been projecting flimsy opportunities for a fresh coating of snow through Christmas day. But in the last two model runs, there are clearer signals of potential Christmas Day snowfall.
Most of the accumulated snow in this European model actually falls ON Christmas Day.
The Canadian model is a little more aggressive, if not overly so. I should add that in going through that model frame-by-frame, at least half of those more substantial accumulations also actually fall on Christmas Day, but with a few Christmas Eve inches as well.
As for the American GFS, its graphic representation is clunkier, but it, too, offers some hope for light to moderate snow accumulation by Christmas Eve and Christmas.
In the meantime, most areas to the south of the city have a whole lot of melting insurance provided by the very abundant lake-effect accumulation that has built up this month.
Worst-case scenario for those who want a traditional White Christmas is having to settle for some old, stale and possibly dirty snow where it survives, mainly on hills. As you can see with your own eyes, the accumulated snow reserve on the Niagara Frontier is sparse and is already mostly gone as of Tuesday. Given the mild temperatures most days and a pretty decent shot of rain Friday night into Saturday morning, we’ll need a fresh coating on the Niagara Frontier, because the old snow will have vanished. The American GFS may be dicey for reliability this far in advance, but it does offer this for midday on Dec. 25.
So, all hope for a White Christmas is not lost.
By the way, the arctic air will make a full tilt comeback next week. I don’t suppose a post-Christmas White New Year’s Eve would be a real vote-getter, but it’s a possibility, too.