Those of you with good memories may recall I wrote an outlook article that predicted January would turn predominantly cold. It ran Jan. 1.
Hopefully, many of you will be too busy to open that link to reread the piece. Yes, I did pull back from that in a subsequent article on Jan. 7. That doesn’t undo my first overestimation of the likelihood of more prolonged below average temperatures.
The Jan. 7 article worked out much better after the damage was beginning to set up. I noted the coming January thaw. We did head into a deep freeze for six or seven days, but 17 of the first 24 days of January have had temperatures climb above freezing, including 60 degrees this past Saturday. High temperatures have run above freezing for the last 10 days as of Jan. 25, with each day’s mean temperature 3, 15, 13, 11, 17, 26, 18, 16 and 9 degrees above average.
Most climatologists go by the mean, not high, temperatures for each day to see if this phenomenon qualifies. With that definition, 12 out of 24 days have already had mean temperatures above 32 degrees. By comparison, last January we had 11 days with mean temps over 32 for the entire month of what was undeniably a mild (remember El Niño?) winter. So, this year’s January warmth has been unusual, if not extraordinary.
One of several reasons we’ve had for the recent stretch of warm weather is the placement and strength of, gulp, the polar vortex. When the polar vortex is centered near the north pole, its counterclockwise westerly flow makes it more difficult to get the polar jetstream to deliver much polar air to the south. In a sense, the polar vortex “hogs” the polar air to itself over high latitudes.
Enough of a dip in the jetstream occurred last week at Alaska’s longitude so that incredibly cold air did make it into much of Alaska. Fairbanks dropped to -50 degrees F, and that’s COLD — even for Fairbanks.
Now, with some help from a developing phenomenon called a Sudden Stratospheric Warming, we are growing more confident the polar jetstream will again buckle southward to deliver at least modified polar air to the Great Lakes and the northeast. The polar vortex will weaken somewhat and change position away from the north pole.
This will allow a period of below-average temperatures to bring some typical midwinter cold back to our region, with some lake-effect snow becoming more likely. While the majority of the lake snow will fall over the hilly terrain to the south, there is a chance of occasional forays farther north toward central Erie County during the weekend.
Even with this greater likelihood of colder weather, there is less confidence in its persistence than there was a couple of weeks ago. However, odds currently favor more of February being colder than average than what we experienced in January.
Lake Erie was 34 degrees at Buffalo on the morning of Jan. 25, 1 degree above average and essentially wide open. It is true, though, that polar air aloft at about 5,000 feet now has to be colder than earlier in the season to produce truly heavy lake snows, because there will be less of a difference between the chilly lake temperature and the air aloft than there was in early December.
In the meantime, look what our potent January thaw did to Lake Erie ice cover during the month. Here is current ice cover:
And at left is how things have changed during the month since our cold period. Note the spikes and the steep decline.
Another spike is coming with the arrival of significantly colder temperatures by the weekend and next week. But when you’re down to under 5 percent on Jan. 24, and the angle of the sun is climbing each day, we are a long way off from the lake's freezing over.