Freezing Rain Wednesday Night?
There’s a reasonable chance that metro Atlanta might get its first wintry weather Wednesday night and into Thursday, but the forecast is tricky, and a lot of what will happen will depend on exactly how conditions set up.
During the day Wednesday, North Georgia will be under control of a high pressure system located over Virginia. This will make for a chilly day again. Meanwhile, a low pressure system is moving east. It’s the same one that has brought freezing rain to Texas earlier this week. Whether we get a major winter event depends on how these two systems interact.
As the warm, moist air moves into Georgia, it will meet the colder air. Since the colder air is heavier than the warmer air, it will remain below the warm air. This effect is called Cold Air Damming, or popularly, ‘the wedge’. The possible effect is that instead of temperatures rising with the incoming rainfall, it will remain cold enough at the surface to cause sleet or freezing rain.
Below is the Weather Service graphical forecast for 7 AM on Thursday:
You can see that below Macon, there will be heavier precipitation, and it will be all rainfall. There’s an area north of that that may see heavier icing, since it will be in the more active part of the rainy sector, while also under the influence of the wedge. North of a line from Columbus to Athens, including Gwinnett County, freezing rain is also predicted.
So what happens on Thursday morning is a function of how strong a wedge develops, and how fast the precipitation moves. Since the ground is warm because of the springlike weather we saw before today, there isn’t likely to be any accumulation on the ground. However, if we do get freezing rain, it will affect trees and power lines, and things could turn nasty. If it’s too cold, we get sleet, which won’t be a problem. And, if the wedge is weak, we may get all rain as temperatures close to the surface remain above 32 degrees.
Stay tuned…
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