CHARLOTTE, N.C. -- The Arctic air has arrived Tuesday with highs only in the 30s and extremely dry air. This air mass is not in a big hurry to leave our area either. This is why a late week storm may bring a serious threat for ice more than snow.
Right now a huge low over the Pacific is breaking off a small piece of energy, which is forecast to move across the Canadian and U.S. border later Tuesday night.
This quick moving system will bring some moisture with it from the Pacific and maybe a bit from the Gulf of Mexico. That really is the big question mark right now: How much more moisture does it grab from the south, if any at all?
The concern is even if there is limited moisture, which it looks like there will be right now. The cold dry air in place over us would cause that moisture to fall as rain into a cold, dry surface layer of air. This, in turn, would cause freezing rain to form. This cold dry air often gets trapped on the east side of the mountains and across the Piedmont in what we call the "Cold Wedge." The GFS model shows this mixed bag of precipitation starting during the day on Friday.
Initially the cold layer is deep enough for snow or sleet but as the warm air aloft moves in this would change it over to freezing rain as the day goes on.
So while the amounts of precipitation will be light if it's primarily frozen or freezing on the way down, the impacts could be large--especially for the Friday evening commute. Like a lot of these storms around here, there are many moving parts, which even with small changes can have huge impacts on the forecast.
Right now I would expect a mixed bag of wintry precipitation starting as early as Friday morning, With the worst conditions late Friday into the evening. The GFS model shows small snow/sleet accumulations but again coupled with freezing rain could be a real mess.
It's not just one model, either. The ECMWF model or European model shows even more sleet and snow. Below is a side-by-side comparison.
There is reason to put more faith in these models right now because they have better data in them. NOAA has been flying some winter storm reconnaissance missions over the Pacific to collect and add data to the model suite. This is similar to what they do during Hurricane season. So there is slightly better data going into the computer models right now from an area of the Pacific that is usually a data void for the models.
There are three options as I see it right now with the track.
So for now I will stick with a mix and keep my snow meter at a 1 just because of the small amounts. We may need an ice meter if this trend continues.
Stay with the First Warn Storm Team for the latest and most accurate information on this potential winter storm. You can also get updates anytime on WCNC.com or by following me on Twitter @wxbrad or on my Facebook Page.