Our spring-like interlude ended with the passage of a cold front early this morning, but real winter weather — complete with bone-chilling temperatures and snow — is on its way back to the northern Cumberland Plateau region next week.
After a few days of seasonable February weather — with nighttime lows in the 20s and afternoon highs in the 40s — we’ll see a colder air mass invade the region early next week, carrying with it a prolonged chance of snow.
The cold: As I blogged Monday, I am largely unimpressed with the hype surrounding next week’s anticipated arctic chill. If you hang out on social media networks much, you’ve seen the hype — the maps depicting frigid temperatures, the graphics warning of bursting pipes.
Perhaps in a winter where cold air — true cold air — has been largely absent, the hype is justifiable. To be sure, it’s going to get cold next week — quite cold, in fact, with what might well be our coldest temperatures of the season. But it won’t be anything more than a typical winter cold spell. We aren’t going to see record-breaking temperatures, and we aren’t going to see cold that just lingers for day after day. In fact, it doesn’t currently look as though we’ll get as cold as we did during the miserable February 2015 mess.
Here’s what the National Weather Service’s Morristown office says about this looming cold snap in a forecast discussion this morning: “Big changes are in store for the beginning of the work week as a trough races quickly out of the northern Plains into the Tennessee Valley. Cold air will spill down from Canada with this system”
The 0z run of the GFS model keeps temperatures in the 20s Tuesday and Wednesday afternoons with lows in the single digits Wednesday morning and in the low teens Thursday morning.
The 6z run of the same model is much the same, but keeps Wednesday’s daytime temperatures even colder.
On the other hand, though, the ECMWF (European) model depicts the same arctic front but keeps temps warmer than its GFS counterpart. This is normally a reliable model and you’ll see forecasters account for it a bit in their forecasts. For now, the official forecast from the NWS’s Morristown office keeps us in the mid 30s on the northern plateau Tuesday afternoon, while the NWS’s Nashville office keeps us right at freezing — 32 degrees — that afternoon. Those numbers will likely be adjusted downward as we get closer.
The snow: A series of shortwave features will accompany this trough in the aftermath of the arctic cold front next week, producing snow showers in the northwest flow that sets up. These northern plateau region typically cashes in on these systems, and the snow sometimes tends to be what we often refer to as “dry” snow — snow with very little water content that piles up easily. The standard snow accumulation ratio is 10:1, meaning a tenth of an inch of liquid precipitation produces an inch of snow. But with setups like the one we’ll see next week, that same tenth of an inch of liquid precip can sometimes produce an inch and a half of snow or even two inches of snow.
For now, the GFS is depicting a total of about 4 inches of snow for the northern Cumberland Plateau on Tuesday into early Wednesday. The NWS’s Morristown office notes the same in their morning discussion, noting the potential for 2-4 inches of snow across East Tennessee with higher amounts across the higher elevations.
The duration: Unlike some arctic cold snaps we see in these parts, this one looks like it could be relatively short-lived. With a positive North Atlantic Oscillation and no blocking in the northern Atlantic region, there’s nothing to “lock” this cold air in, and the pattern remains relatively progressive. So after a couple of days below freezing, we could be back above freezing as soon as Thursday afternoon. The GFS has picked up on a replenishing shot of cold air as we move into Valentines Day weekend that could drop temperatures back into the teens or even the single digits, but, again, it doesn’t appear to have much staying power and a warmup is expected ahead of the next storm system, which should impact the region around Feb. 17-18.
Winter’s last hurrah? Except for a foot of snow to close out January — never a small feat in this part of the world — the winter of 2015-2016 has been largely non-existent. We knew Ol’ Man Winter would return with a vengeance after a reshuffling of the deck to start this month, but the question now becomes whether next week’s arctic wave will be his last hurrah.
That remains to be seen. There are some indices that become less favorable for cold and snow once we get past next week. I wouldn’t bet on an early spring, with temperatures constantly in the 60s and 70s; we will likely see more cold snaps and perhaps even more chances of snow as we get into the end of February and on into March. But let’s face it: by the time we move past next week’s cold snap, we’ll be in the second half of February. The days are getting longer, the sun is climbing higher into the sky, and it is this time of year when the first frogs — the spring peepers — start to sing from the pond banks and marshes. Strictly from a climatological aspect, winter will be on life support once we get past next week’s cold snap.
The bottom line: Much colder weather is on the way for next week, with at least 60 hours or so of below-freezing conditions. It won’t be an unordinary cold snap for winter, and it won’t last too long, but it will be much colder than we’re accustomed to this El Nino winter, and milder air won’t truly return for about a week. Snow is also possible, with moderate accumulations not out of the equation.
The disclaimer: I’m not a meteorologist and I don’t even play one on TV. I don’t pretend to be a weather expert; I’m just an amateur weather enthusiast who happens to have a blog. As always, stay tuned to the National Weather Service or your favorite broadcast meteorologist for the latest, most up-to-date forecast.