When I told y'all we were heading into a weather pattern with winter storm chances, I wasn't kidding. Here we go again for this weekend; there's a risk for a high-impact winter storm.
To set the stage:
- We'll remain tranquil through Wednesday night under high pressure drifting through the region; temperatures will remain below average in this polar air mass.
- The next cold front will arrive on Thursday, then slowly press southward. We'll have rain chances in the Upstate on Thursday from this feature, then over most of the state on Friday.
- Frigid arctic air will work into South Carolina behind the front Friday night through the weekend.
The arrival of the harsh cold will set us up for a widespread winter storm over the Southeast once a storm currently about 1,000 miles west of Northern California crosses the region Saturday into Sunday.
There is a lot more we don't know now than what is known. We know there's a risk of a winter storm over at least part of South Carolina this weekend. It could be a high-impact event because the storm will pull in plenty of moisture from the south. We know that the northern part of the state has a higher risk for impactful snow and ice than the south, but no point in the state is free of the risk. The signal the computer models are giving us right now reminds me a lot of the winter storm of mid-February 2014 (link to our report on that storm, though I'm sure many in the audience recall it well). We also know it will remain cold behind the storm, so if the storm causes significant snow and sleet accumulations, the melting process will be slow.
Questions loom large about the storm track and how much this storm, moving through the southern part of the jet stream aloft, will interact with features moving through the northern part of the jet stream. We also don't know for sure how fast the storm will move, and timing will be critical, because the later the storm begins in South Carolina, the more time the cold air will have to get entrenched, and that would mean more of the state would be affected by winter precipitation. Meanwhile, a faster-moving storm that takes a track to the north of the range we see in the models would have limited impacts, likely just some ice buildup in the northern part of the state.
The current model consensus is for the storm to produce a band of heavy snow (think double-digit accumulations) on its northern flank. Most of the models have the core of this over Tennessee and North Carolina, with some of it bleeding over into northern South Carolina. Then, south of the snow area, the models agree that a large area will see a mix of potentially heavy sleet and freezing rain, which could cover most of the Palmetto State. A more northward storm track would allow much of South Carolina to escape with a cold rain, with ice confined to the northern part of the state. A more southward storm track would bring heavy snow to more of northern South Carolina and a potentially severe ice storm to the south.
Total snowfall through 7 a.m. Monday from the GEFS model, showing forecast snow accumulation across the southeast from each ensemble member. This shows a range of possibilities for snow accumulation from the upcoming storm that depend on the storm's track. Keep in mind that we are likely to see a wide area of freezing rain and sleet to the south of the band of snow.
Image Source: WeatherBELL
So, what do you do now? It sure does sound scary, and I do not doubt that grocery stores are seeing a surge in sales of milk sandwich ingredients because of the social media buzz about this situation. You don't need to panic but it's always good to prepare. Start by reviewing SCEMD's SC Winter Weather Guide and decide which suggestions there fit your situation.
I'll have updates daily until the storm arrives.