Key Points:
- A storm moving through South Carolina on Wednesday will cause winter precipitation across the north, with cold rain falling elsewhere.
- Primarily snow will fall along and north of I-85 in the Upstate, but with it coming mostly during daytime and surface temperatures slightly above freezing, roads will mainly be wet. Icy spots may develop Wednesday night as temperatures fall below freezing.
- Further east, near the Catawba River, a mix of rain and snow is likely Wednesday and possibly Wednesday evening, with possible snow accumulations along the state line. Roads will mainly be wet Wednesday but could become icy Wednesday night.
- Inland parts of the Pee Dee could see a mix of snow, sleet, and freezing rain Wednesday afternoon and evening; roads could become icy Wednesday night.
- While northern parts of the Midlands and Central Savannah River Area may see a rain-snow mix or a period of snow, primarily rain will fall in these regions. Subfreezing temperatures Wednesday night could result in isolated icy patches into Thursday morning.
- The Lowcountry will see only rain.
- A cold front moving through late Wednesday night and early Thursday might trigger a snow flurry or two over the northern part of the state, but accumulations are unlikely.
- Frigid air moves in for the end of the week; Friday morning's lows will be comparable to the colder nights we saw in January.
Confidence is increasing that a minor winter storm will affect a part of the state on Wednesday into Wednesday night. Impacts will be limited, but you'll want to be ready if you're in an affected area.
There remains some uncertainty about the storm's character because temperatures will be marginal at the surface and aloft. One degree at the surface or aloft could make the difference in whether any point sees snow, ice, or cold rain. So, you'll want to stay in touch with the weather, as the forecast could change as Wednesday approaches.
One change from before is that this looks like a 1-2 punch, with the main event coming on Wednesday as a storm over the Northwest today reaches the Southeast. A second, very minor wave of precipitation is possible late Wednesday night into Thursday morning as a strong cold front moves through.
Snow lovers, this is a near miss on a significant snowstorm. Had the cold front moved in sooner, the gelid air behind it would have resulted in at least a few inches of snow over a large part of the state.
Infrared satellite imagery from this morning shows a few interesting features:
- Clouds associated with a storm over the West that will bring a winter storm to parts of the Mid-Atlantic and Southeast on Wednesday.
- Clouds downwind of the Great Lakes, particularly Lake Michigan, associated with lake effect snow.
- Extreme cold is evident (as the satellite is sensing temperatures to help detect clouds) over the Dakotas, Minnesota, Montana and the Canadian Prairies, where today's low temperatures were -20 to -40°F under a clear sky.
- Clouds were swirling around a storm over eastern Canada and northern New England.
Image source: University of Wisconsin RealEarth
I'll handle this on a regional basis.
Upstate:
Here, we will see mainly snow along and north of I-85. Some sleet and rain may mix in at times. Surface temperatures mostly above freezing will prevent much from accumulating during the day, but there could be a coating on the grass, car tops, and other elevated surfaces. It will be a situation where 1-3 inches worth of snow falls from the sky, but most places will see less than an inch of slush accumulate. Those traveling will encounter mainly wet roads, but caution will be needed because there might be accumulations in shady areas. Roads could get slick Wednesday night as temperatures fall below freezing, but precipitation will end here around nightfall.
South of I-85, a light rain and snow mix will fall, but accumulations are unlikely. Subfreezing temperatures Wednesday night could result in some icy spots on the roads as lingering puddles freeze.
The cold front coming late Wednesday night into Thursday morning could trigger snow flurries. However, moisture will be sparse, and it's unlikely we see more than a little dusting.
Catawba River Area:
We have more uncertainty here as temperatures will be near freezing at the surface and aloft. Wednesday will bring a mix of snow, sleet and rain. York County has a better chance of seeing a snow accumulation than Chester and Lancaster. However, most precipitation falls during the day, so most of what isn't liquid will melt quickly. Snow and rain may linger more into the evening here, which could result in the ground getting covered in some areas or more lingering water on the roads, so icy patches are a concern for Wednesday night into Thursday morning.
The cold front late Wednesday night and early Thursday may trigger a few flurries here; perhaps there is a fresh dusting in spots.
Pee Dee:
Uncertainty is higher here as there are differences among the computer models. Some show surface cold air getting locked in, with surface temperatures close to 32°, while rain falls Wednesday afternoon and evening. Others keep temperatures above freezing, indicating that only a cold rain will fall. Most models hint that it may be cold enough aloft over Chesterfield and Marlboro Counties that some light snow and sleet fall with perhaps an inch accumulating. Temperatures will drop below freezing on Wednesday night, so there will be a risk for icy spots to develop, even where only rain falls as lingering wet spots freeze.
Thursday morning's cold front might cause a flurry or two, but accumulations are unlikely.
Midlands and Central Savannah River Area:
Wednesday should bring a cold rain, but some wet snow can mix in over northern areas. I don't expect to see any significant travel impacts beyond wet roads during the day on Wednesday. The rain will end during the evening, and temperatures will fall below freezing at night, so frozen puddles can lead to an icy patch here and there, so plan to allow extra travel time on Thursday morning.
The cold front coming Wednesday night and Thursday morning might squeeze out a flurry, especially across the north, but I don't expect to see any accumulation.
Lowcountry:
It'll be all rain here, y'all. Far inland, it will get below freezing Wednesday night, which might result in an icy patch here and there from frozen puddles on Thursday morning.
The cold front passage Thursday morning will likely be dry in the Lowcountry.
Behind the Storm:
An extremely cold air mass currently over the northern Plains, Upper Midwest, and Canadian Prairies will push into the eastern part of the country for the end of the week. It won't stay long; a slow warmup will commence on Saturday. Highs will mainly be in the 30s and 40s on Thursday and Friday, then 40s and 50s on Saturday, and mainly 50s on Sunday. The coldest time will be Thursday night into Friday morning, with lows Friday morning ranging from the middle teens over parts of the Upstate and Catawba River Area to the upper 20s along the Lowcountry coast. That's almost as cold as coldest nights we had in January.
The next storm in line arrives early next week, which will likely be a chilly rain.
Traveler's Advisory:
On Wednesday, those traveling into western and north-central North Carolina, Tennessee, Kentucky, West Virginia, and Virginia will encounter a snowstorm causing dangerous travel conditions. I recommend delaying travel to that area until road crews have the roads cleared.