A cold front will move in from the west tonight, throwing a round of moisture into the Carolinas. For almost all of our foothill counties, this will mean a chilly, raw light rain. However, the combination of lingering cold air and higher elevations along the Blue Ridge and the highest ridges of the South Mountains will be just chilly enough to support pockets of freezing rain.
This is not a major ice storm setup. Based on the latest high-resolution guidance and the National Blend of Models (NBM), any icing looks very light and very isolated – more of a “nuisance glaze” threat than anything widespread.
What the models are showing
We’ve looked at three key pieces of guidance for this event:
- NAM 3 km: Shows very patchy areas of freezing rain along the Blue Ridge and the highest South Mountain ridges, generally on the order of a few hundredths of an inch or less.
- HRRR 3 km: Very similar idea, with scattered specks of light icing mainly confined to the higher terrain and just north and west of our coverage area.
- NBM 2.5 km (Flat Ice Accumulation): The blend smooths things out a bit and paints a narrow band of light ice from northeast Georgia into the NC mountains and Blue Ridge, with amounts generally 0.01″ to around 0.05″ at most.
- Even the SREF ensemble, which averages dozens of model members, only paints about 0.03″–0.05″ of ice across the high ridges of the South Mountains and Blue Ridge, with at most a tenth of an inch on the coldest peaks. That’s solid support for a very light, elevation-driven icing event rather than an actual ice storm.
When you step back and look at all three, ensemble data, and SREF Plumes the signal is consistent:
- The best chance for any ice is limited to the Blue Ridge escarpment and the highest elevations of the South Mountains.
- Even there, we’re talking about a thin glaze at most.
- The overwhelming majority of Burke, Caldwell, McDowell, Rutherford, Polk, Alexander, Catawba, Cleveland, and Lincoln counties are expected to see plain cold rain with temperatures above freezing.
Timing
- Late tonight: Moisture increases from southwest to northeast. Temperatures near the Blue Ridge and the highest South Mountain peaks hover around 30–32°.
- Toward daybreak and Sunday morning: Precipitation becomes more scattered, and surface temperatures slowly nudge above freezing in most locations, further limiting the potential for icing.
For most of the region: low clouds, light to moderate cold rain, and that “bone-chill” wedge feel.
Who has the best chance at ice?
The light icing risk is focused on:
- Ridgetops and gaps along the Blue Ridge, generally above about 2500–3000 feet
- The highest elevations in the South Mountains
In these spots, elevated surfaces – trees, decks, railings, and perhaps a few higher bridges – could pick up a very thin glaze. Roads in the valleys and along the I-40 corridor are expected to stay mainly wet with temperatures a little above freezing.
Official Forecast:
- South Mountains:
- 0.01–0.03″ on exposed trees, decks, and railings along the South Mountains crest (Buzzard’s Roost, Benn Knob, upper Chestnut Knob slopes).
- Eastern Escarpment (over-achieving cold spots on the escarpment):
- Up to 0.05″ near the Blue Ridge escarpment (Jonas Ridge / Linville Gorge rim, Gingercake, Little Switzerland, Black Mountain, Blowing Rock, Grandmother Mtn., Grandmother Mountain), if temperatures hang at or below 32°F during the heaviest showers.
Roadway impacts even on those ridges should be pretty limited and patchy; the I-40 corridor and most foothill communities stay all liquid.
Why is this freezing rain and not snow
Tonight’s setup is textbook cold-air damming (CAD), just not particularly strong.
Think of the atmosphere in layers:
- Near the ground: A shallow layer of near-freezing or slightly sub-freezing air is trapped against the east side of the mountains by high pressure to our north. That’s the cold “wedge” that slides down the eastern slopes.
- A few thousand feet up: Southwest winds are pulling in warmer air over the top of that wedge. In this layer, temperatures are above 32°F, so any snowflakes falling from higher up melt into raindrops.
- Back at the surface: Those raindrops then fall through the shallow cold layer. Where the ground and objects are at or just below freezing, the drops become supercooled and freeze on contact – that’s freezing rain.
For snow, we’d need the whole column – from the ground all the way up through that mid-level warm layer – to stay at or below freezing. Tonight, the warm “nose” aloft is too strong, and the wedge is too shallow, so we end up with liquid precipitation falling into a marginally cold surface layer instead of snowflakes surviving all the way down.
Expected impacts
- Travel: Widespread travel problems are not expected. A few slick spots are possible on the highest ridges and bridges where temperatures hang around 30–32°, especially just before and around daybreak.
- Power: With ice amounts limited to a thin glaze (a few hundredths of an inch), significant power issues are unlikely.
- General conditions: Damp, chilly, and raw with periods of cold rain for almost everyone.
Bottom line
- This will be a very light and very isolated freezing rain event focused on the Blue Ridge and the highest South Mountain ridges.
- The NBM, NAM, and HRRR all agree that any icing is limited to a thin glaze, with totals generally 0.05″ or less.
- Most of our coverage area will see plain cold rain with temperatures above freezing and only minor impacts.
We’ll keep an eye on temperatures in the usual mountain cold pockets tonight in case the wedge overachieves, but at this time, a significant icing event is not anticipated.