Winter Weather Event December 8-11

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GON Winter Weatherman
I will try and be as brief as possible and as clear as possible but probably neither will happen.

In my mind there are 2 parts to this event… actually 3. First part is the rain and this is the bigger story than the other 2. The amount of rain this system will produce is impressive. Anywhere north of the Florida / Georgia line could see 3-5” of rain before it all ends on Tuesday. So keep that in mind.
2nd part of the story is the icing / sleet potential. The NAM model has different modes within the model. It all depends on which mode you want to believe. The two I will highlight are the 3K and the 12K modes. Just for reference, the NAM was the ONLY model that screamed for the foot of snow that the NW side of the state got this time last December. I remember a lot of TV mets that laughed and said that the NAM was drunk. One even took to twitter to tell me I was wrong to even entertain the idea of the NAM for that event. His name rhymes with Burns. Anyways, don’t discount what the NAM is smoking, last year it was good stuff. The NAM is very good at sniffing out CAD (Cold Air Damming) events. This one is no different. The big question is, how much evaparational cooling will happen, how strong will the High Pressure up in the NE be and how much will accumulate. Great question, I don’t know the answer and neither does any TV Met or professional met. This system is not clear cut at all it could be nothing, a little or a lot. Just too close to make a call of definite measure. Also, the ground is going to be too warm for accumulating ice, so visions of cars sliding around on frozen roads is not happening except in the mountains and even then it would take a lot. Bridges could be a different story and will be where the temp is below 32°. I do believe the N. GA areas near the mountains will definitely see a sleet / freezing rain / snow (at times) mixture. The only “threat” I see to the CAD prone areas is ice forming on trees and power lines. This “threat” will be at it’s highest Saturday night into Sunday… all day Sunday into Sunday night.

3rd part and this is the more interesting part in my mind. As the storm pulls off the coast there is moisture left behind and again, temps will be on the razor edge, however the difference is the columns in the atmosphere will be cold enough for all snow. Temps at the surface will be right at or just above freezing. With snow falling through the atmosphere, again evaporational cooling can take place and cause the snow to accumulate. Yes, snow can accumulate differently than Ice. If it comes down at a good enough rate, the soil temp becomes meaningless to accumulating snow.
My last thoughts is this: Models, their graphics, their temps, dewpoints… all the data they crank out, is not written in stone and when you have systems that are dynamic and walk a fine line of rain vs. snow or rain vs. freezing rain, many times it’s simply a guessing game and anyone’s guess is as good as the next guy’s. My gut feeling is this, cold 33-34° rain for most that live in the CAD prone areas. Outside of CAD prone areas 34-38° and raining. However, people from around Danielsville, up to Gainesville, Toccoa and the NE GA mountains, I expect Freezing rain and sleet to dominate sometime Saturday night / Sunday morning through the day on Sunday and into Sunday night. It could be a real back breaker for those areas. From a line just south of Athens, over to Lawrenceville, back up towards Cumming, Buford, Dahlonega and Hiawassee this will be the truly unknown. It will either be a nasty rain or people reporting ice piling up in the trees. Same time frame as above. Into Monday day and all the way through Tuesday I believe we will see snow showers and it will not be a blanket thing. Cumming could be getting a heavy shower and Dacula has nothing. The snow shower coverage should be anywhere north of I-20 in the state of Georgia. That is what I expect to see Monday / Tuesday. Will it accumulate? I do not know and quite frankly that is a ways out in the weather world. I mean look, we are talking about possibly having freezing rain in the NE GA area tomorrow night and we can’t even nail that down.

I am going to post a few snow maps from the latest runs. I would take the details of the maps with amounts and areas with a grain of salt. Also freezing rain maps as well as the National Weather Service’s map that is their latest guess. I will also have my personal guess as well.