We want to wish everyone a Merry Christmas and a Happy New Year! We should remain fairly quiet for Christmas Day and through the middle part of this week. The weather pattern will become very active by Thursday and Friday, and that could result in a winter storm for parts of North Georgia and into the Carolinas. The pattern looks to remain very active as we head into the first week of 2018 too.
After looking over several model runs over the past several days, we have enough confidence to forecast the potential for a winter storm developing on Thursday evening and Friday of this week (12/28- 12/29/17). Since we are several days away, we can’t go into specifics. We just want to explain the overall setup and give you a heads up.
Timing: Thursday night and all day Friday (12/28/17 and 12/29/17)
Most Likely Impact: Freezing Rain/Sleet
An area of high pressure from Canada will build into the Eastern United States Wednesday and Thursday. It will move into the northeast and provide a classic setup of the “wedge”.
We have cold air in place at the surface, but temperatures appear to warm as you go up into the atmosphere. This looks like a classic cold air damming event that would give you more of a freezing rain or sleet mix versus all snow.
Models are also showing moisture developing along the Gulf Coast and spreading into Georgia Thursday night and Friday. With moisture meeting cold air, that can sometimes spell trouble for someone in the Southeast.
Two biggest questions we simply can’t answer as of this time:
1) How much moisture will be associated with this storm?
2) What is the precipitation type? (Based on temperatures at the surface and aloft.)
Here’s a look at the 12z GFS and European models from today (12/24/17). They both show pink in North Georgia, which would indicate a freezing rain threat. This could easily change if the temperatures are colder/warmer. As of now, the threat appears to be mainly along and north of I-20. Could that change? Of course!
Remember that freezing rain falls as a cold rain. When it hits the surface, temperatures are at or below freezing (32F) and the rain can freeze over as ice. Freezing rain can result in treacherous travel, downed trees, and power outages. Sleet would result in less impacts if temperatures are a little cooler than what these models are indicating.
Still too early to go into specifics regarding the wintry threat late Thursday night into Friday. We can say with some confidence that a storm is looking possible. We just want to give you a heads up especially if you have plans on traveling across Metro Atlanta/Athens during the holidays (or to travel to Pasadena, California for the Rose Bowl). We’ll have a better idea of the timing, precip type, and who sees what by Wednesday. A lot can change between now and then. There is no certainty when it comes to winter forecasting.
We hope 2018 promises to be a good year for you. You won’t hear from us a lot unless the weather becomes extremely active.