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Major winter storm unfolding across the south

January 29, 8:58 AM
Raleigh Weather Examiner
Allan Huffman

“Major winter storm unfolding in the southern US”

Our major southeast winter storm is currently pounding the southern plains with snow and ice yesterday in Texas and Oklahoma, and moving into southern Missouri and Arkansas today. This may be remembered as an I-40 winter storm as the precip expands east and seems to focus along I-40 the next 48 hours.

Cold and dry air is moving into North Carolina this morning with temperatures in the low to mid 30s and dewpoints in the teens. This air mass is setting the stage for our winter storm and will continue to be advected in by a building surface high in the Great Lakes that will ridge into the northeast US the next few days.

Ok, so down to the storm. I have updated my map below with the latest forecast. I will issue updates to the map if I see a need to make a change to the zones.

Zone A: I think a band of 12-18 inches of snow could fall across the extreme northern North Carolina piedmont as well as the southern Virginia border counties. This area should see mostly all snow although I can not rule out a little sleet in the eastern sections of this zone.

Zone B: This area will see a substantial snow with as much as 6-10 inches likely. Most areas will likely see all snow from this in this zone. If there is any last minute trend north, this area could see closer to a foot or more, if there is a last second trend south some areas in this zone will only see light accumulations.

Zone C: This zone which includes most of the I-40 corridor in North Carolina from Hickory to Raleigh as well as the northeast piedmont will likely see a snow/sleet mix with more snow than sleet. We will see a substantial period of all snow to start which could accumulate to 6-8 inches. Then by Saturday morning sleet could mix in and limit further big snow accumulations, a change back to snow with light snow accumulations is likely Saturday afternoon and evening. IF, we see less sleet mix in, this area could easily see 12-15 inches of snow. For now though, I think we do see some sleet mix in and thus this area will see 8-12 inches of total snow and sleet accumulation.

Zone D: To keep continuity I kept the major ice area zone D. I have shifted this a little south though, south of the Charlotte area. This region from the North Carolina sandhills into the southeast piedmont and much of upstate South Carolina and extreme NE Georgia could see a severe ice storm. I think at least 0.5 inch of ice accrual will occur with as much as 1 inch of ice accrual possible. This will be a severe event and you should be ready to lose trees and power. The western part of this zone could see the precip begin as rain and snow and change to snow with some light accumulations before a change to freezing rain.

Zone E: This zone lies between the severe ice storm and the zone that will see mostly snow and only some sleet. I think this zone sees a healthy mix of snow and sleet especially from the southern foothills east, that will accumulate to 4-8 inches. The southern mountains could see more snow than sleet and could end up higher than 8 inches, but for now this seems like a good call.

Zone F: This zone will see significant ice, but not as much as zone D. Many areas will likely start as rain and transition to ice. I could see 0.25-0.5 inch ice accrual of freezing rain in this zone. Areas south of this zone could see some marginal freezing rain but not as much as this area.

Zone G: This zone will likely see rain change to snow or sleet Saturday. For now I will keep accumulations light at 1-2 inches, but this will be an area to monitor to see when the changeover occurs.

Zone H: This is a tricky area, and I don’t pretend to know southeast Tennessee climo well. It looks like a mess that could go either way, some runs have shown a heavy wet snow and other mostly rain. I think a mixed bag will fall here with some snow accumulation likely.

I also want to mention that the models are showing the possibility for thunder Saturday morning into early afternoon in northern North Carolina and southern Virginia. So don’t be surprised if you hear thunder tomorrow morning in those areas.

Very cold weather will follow this storm the snow cover causing very cold overnight lows and reducing the warming potential during the day. For now the models look paltry for any precipitation Tuesday/Wednesday but if some does come we may have to worry about at least some freezing rain. For now I leave that mention out.