It’s going to be a close call again for a really cold rain or some ice Thursday night into Friday morning. No matter what it looks like a very nasty night Thursday and most of Friday morning with tons of clouds and a very, very cold rain.
Here’s the low down on what I think will unfold.
1st we have the classic “Cold Air Damming” set up with arctic high pressure to the northeast over New England. This will push very cold and dry surface air down along the eastern slopes of the Appalachians Thursday into Friday.
At the same time low pressure will develop along the stalled Arctic front to the south over the Gulf of Mexico and move northeast.
The classic overrunning of warmer air aloft over the shallow cold layer at the surface develops Thursday evening.
The question is always how thick the cold air is and how warm the air gets above it. Also the Arctic high won’t be anchored in place to keep the cold air pumping south. So there is a good chance the warm air aloft can win out eventually over the cold surface air.
The soundings around Charlotte look like that the warm nose will just be too strong and the cold air at the surface just warm enough for a cold rain. The problem is it’s close and the surface air could be a just a tad colder and we could see at least a few hours of ice early Friday.
Here’s the forecasted temperature profile for 2am Friday morning:
So Here’s what I’m thinking:
The NAM 4 model usually has a really good handle on the temperature profiles. So I’m sticking close to them on this one. I bet we see a brief period of freezing rain around Charlotte but it quickly changes to a very cold rain late Thursday.
Areas along and north of I-40 will have to be watched for a longer duration of freezing rain. The highest risk areas will be on the eastern facing slopes of the Blue Ridge and the Triad area near Greensboro. Here’s a 4 panel of the Futurecast with rain and ice. Purple is ice or freezing rain.
The total ice accumulation from the NAM model has a bull’s eye over the Triad back through Iredell and Alexander counties.
The temperatures along I-40 there could hold on to below freezing for many more hours creating an issue by Friday morning.
The probabilities of ice are centered along I-40 from the Blue Ridge into the Triad. Here I expect 0.10” of ice to maybe as high as 0.15” before changing to all rain. Even further south don’t be surprised for a quick glaze on elevated surfaces before it all changes to a miserably cold rain around Charlotte and northern Mecklenburg county.
Stay tuned for updates, most roads will be fine but if it’s slightly colder then we might have some issues. Leaning towards a cold rain mostly right for now.