A complicated weather pattern developing over the weekend means parts of South Carolina will face a threat of frozen precipitation - the greatest chance so far this year.
While nearby states in the Tennessee Valley and the northern mid-Atlantic are expected to see heavier accumulations, enough cold air and moisture appear to be in place for the Palmetto State to also experience impacts.
Ice, in the form of freezing rain and sleet, appears to be the primary concern, rather than snowfall or flooding from rainfall, which could lead to travel delays and even power outages.
Due to the potential for hazardous weather, residents are encouraged to stay informed and be prepared in the event that travel becomes treacherous over the weekend.
Weather pattern set-up
At the heart of the setup is what is known as a Rex Block over the Pacific Ocean.
This blocking pattern is directing the jet stream sharply northward into the Arctic before plunging it southward again, allowing extremely cold air to be driven deep into the continental United States.
At the same time, the southern jet is forecast to funnel Pacific moisture into the Gulf Coast region before tracking up the Eastern Seaboard.
Additionally, an area of low pressure is expected to develop east of the Rockies, which will help enhance moisture from the Gulf.
Where the two main air masses clash, the potential exists for significant winter weather, but because so many forces are at play, the potential impact zone remains broad and includes parts of South Carolina.
Additionally, the slow movement of the system will set the stage for a long-duration event, which can lead to increased precipitation totals, especially in regions not accustomed to seeing frozen precipitation.
Expected timing and accumulations
Forecast models show clouds increasing throughout Thursday and precipitation developing on Friday, but due to warmer air in place, initial rounds of precipitation are expected to fall as rain.
The potential for snow and ice increases on Saturday and may overtake much of the state by Sunday.
While the threat of snow accumulation appears minimal, ice accretion could become problematic along and north of Interstate 20.
Some forecast models suggest some communities could see at least moderate ice accretion, which would be sufficient to cause scattered power outages and travel problems.
Lower amounts of frozen precipitation are expected along the coast, where warmer air will help moderate temperatures.
Unlike previous events, when cold air briefly followed storm systems, temperatures appear poised to plunge into hard-freeze territory for an extended period during the upcoming workweek.
The Arctic air will likely lead to lows in the teens and 20s, with daytime highs limited to the 30s and 40s next week.
Precipitation amounts may be sufficient for some counties to be placed under a Winter Storm Warning or Ice Storm Warning as the event draws closer.
Alerts issued by the National Weather Service are meant to inform the public of hazardous winter weather and to take immediate actions to protect lives and property.
Be wary of misinformation
With the complex weather outlook, it is important to get your information from accurate and reliable sources.
Throughout the winter, social media has been plagued by forecasts calling for snowfall and historic cold across South Carolina, neither of which have materialized so far.
When the extreme temperature swings of the season are averaged together, temperatures across much of the state through the first half of winter are running near normal to slightly above seasonal averages.
Additionally, instead of any widespread snow events, major reporting sites such as Charleston, Columbia, and Greenville - which typically observe at least some snow by this point in the winter - have yet to see measurable frozen precipitation.
Forecasts for snowfall and ice accumulations typically do not become reliable until about 72 hours before an event, while broader pattern recognition generally improves in the 3- to 5-day time frame.
