Plenty of snow remains here in Big South Fork Country, but it appears more winter weather is on the way.
After Monday’s winter storm dumped between 2-5 inches of snow, sleet and ice across the region, and this morning’s arctic cold front dumped another 2-3 inches, a winter storm watch has been issued for the entire region for Friday afternoon through Saturday afternoon.
Around 5-6 inches of snow remain, even with melting that has occurred, in the Oneida area tonight, and parts of the Big South Fork have nearly 8 inches of snow. While the state roads are primarily clear, all secondary streets and backroads remain snow- and ice-covered and very slick. A full day of sunshine will lead to some improvements tomorrow, but temperatures that struggle to get out of the single digits won’t help much, and most roads will still be slick by the time this next winter storm arrives on Friday, setting up a somewhat rare (in these parts) snow-on-top-of-snow scenario.
There is significant model disagreement with the next system, and it remains to be seen whether snow and ice amounts will even be great enough to warrant winter storm warnings. But, for now, the NWS has issued winter storm watches to cover the possibilities — which run the gamut of snow, sleet and freezing rain.
The entrenched arctic air promises to win out early against strong warm air advection as the next storm arrives and precipitation begins. That’s where the concern lies. The warm air advection will eventually win, but that is likely to be on Saturday. In the beginning, it’s likely that precipitation here on the Cumberland Plateau will be in the form of snow. As the air warms, the mid-layers of the atmosphere will rise above freezing first, which will allow for some sleet and freezing rain. And, eventually, as the surface warms above freezing, everything will change over to all rain for a big, sloppy mess.
But what will the impacts be before that changeover occurs? Today’s 12z run of the GFS model painted a dire picture: Two inches of snow followed by an inch of freezing rain. Obviously that would be a disaster, even if temperatures quickly warmed above freezing. The 12z run of the NAM was less ominous, with between 2-3 inches of snow and around a quarter-inch of freezing rain.
The 0z NAM, which just ran tonight, is a little worse, with 2-3 inches of snow and around a half-inch of freezing rain. The 18z GFS a few hours ago was about the same, with around 2.5 inches of snow and around a half-inch of freezing rain.
Aside from whatever happens this weekend, it looks like the cold weather is here to stay for a while. The warmer temperatures on Saturday will be followed by a frontal passage on Sunday, which will lead to much colder temperatures on Monday — probably high temps in the 20s and low temps in the teens. A reinforcing shot of cold air by the middle of next week could reintroduce us to temps in the teens again. The 0z GFS even brings subzero temperatures back for the first couple of days of March. Obviously that’s an extreme solution and not very likely, but the general idea is that February is going to wind up on the cold side. Some of the latest model guidance tries to build in a nice warmup as we near the end of the first full week of March, but I wouldn’t count on it just yet.
Temperatures in February thus far are averaging a full four degrees below normal, and the average low temperature is even more pronounced — nearly 7.5 degrees below normal. This will wind up as one of the coldest months of February much of Tennessee has ever seen, in all likelihood.
The remarkable thing is that this has happened with the Arctic Oscillation and North Atlantic Oscillation both in positive territory. So if someone ever tells you that a -AO/-NAO regime is a prerequisite for cold weather in the Southeast, tell them they don’t know much.