Chilly Couple of Days: A northeast wind will combine with a cloudy sky to keep Wednesday a bit cooler than what we experienced on Tuesday. Temperatures won't make it out of the 40s in some towns across the Upstate with a few places reaching close to 50°. Western NC will also have a mostly cloudy sky to deal with as temperatures remain in the 40s all day.
Some Sun to End the Week: Thursday will be the day sunshine returns. Temperatures will be cold to start, but upper 50s with sun by the afternoon will be more comfortable.
Weekend - Some Rain Saturday Night: Most of this weekend will be dry, but there is a good possibility of some rain Saturday evening & night into part of Sunday morning. Our sky should clear out again on Sunday.
Storm System to Impact Us Next Week: We are still following a storm system which will impact us early next week. With it being the middle of December and a lack snow-cover to our north, it's safe to say that enough surface cold won't make it down here for any sort of freezing rain threat. Surface sub-32° cold air never really was going to be a factor.
Snow next week is still a very slim chance for Upstate and NE Georgia towns. But, it's a close enough call that it's worth following until the chance can be ruled out entirely. The only way it snows in the Upstate next week is if this storm is intense enough to manufacture its own cold air in a process called dynamic cooling with heavy precipitation rates dragging cold air down from above overwhelming surface temperatures. Without an intense system, there will be no help from surface temperatures (would be more of an icy setup anyway). The dynamic part of the storm will be on the northwestern side which means the storm track will have to be east of us along the coast for Upstate/NE Georgia snow to be a possibility. For Western NC, snow looks more conceivable, but will still be dependent on the strength and track of the system.
Storm System Trends: After following this setup for a few days, several trends can be determined.
1. The system itself hasn't completely disappeared from forecast model output even though that is still a possibility in the coming days.
2. 90% of the data collected suggests a large, strong system either Tuesday or Wednesday of next week impacting parts of the southeast, but it's too early to say who gets what and where. There was one particular forecast model (the 12z European this morning) that suggested a weaker storm so that has to be taken into account. An intense storm would bring the possibility of cold rain to snow transition for some people while a weaker storm would be all rain for every region involved.
3. Then, there's the cold air part of the setup. Forecast models continue to show a lack of cold air at the surface preceding this system. fact is, the middle of December never really offers up much arctic cold for the southeast and that's exactly where we stand in this setup. Without the presence of a strong cold source in the Midwest and OH Valley, this storm will be more likely to track inland instead of along the coast.
4. In terms of storm track, the GFS has been honking on keeping a track close to the Carolinas, while the European has kept the track toward the west moving from Louisiana to Tennessee during the last several days. Interestingly, the newest 12z European (shown to the right) trended toward the GFS taking it toward the coast. Meanwhile, the 12z GFS (shown to the right) brought the track further inland from some of it's previous versions.
The bottom line is to expect rain. Big surprise, right? There is also a very real chance we get dry-slotted and end up with very little rain. After all, we are in a dry spell and drought tends to lead to more drought. Still, a strong storm system is probable, but only a 100-200 mile wide area will have the potential for a rain to snow changeover and that area could be Western North Carolina. As of now, there's no telling where the storm will track and where that dynamic, northwest side will be positioned, but we will have more of an idea by this weekend.
Cold Pattern Toward Christmas?: It is looking more and more probable that the southeast will transition into a colder pattern next week and into Christmas week. Still, I am doubting this will be true arctic air, but I could see upper 40s and 50s for highs with 30s for lows.