Over the past over the weekend, as weather models first began predicting a winter storm would move across much of the country, Sean Sublette, a meteorologist based in Virginia, began advising residents in his area to prepare for snow. At that time, Sublette says, “multiple data began to indicate a significant snowstorm in the mid-Atlantic and Northeast, with significant amounts of ice further south into the Tennessee Valley in the Carolinas.”
Sublette then woke up Wednesday morning. “I look at the data again and say, ‘Oh my gosh,’” he says. The models now constructed the storm in a completely different way.
“Some of the data shows debilitating amounts of ice in my area in central Virginia,” he says. “That doesn’t mean I’m buying hook, line and sinker anymore. But it’s a sobering piece of data that suggests heavy freezing rain, which is the type of precipitation that’s liquid until it touches something and then freezes. That’s what weighs down power lines. That’s what weighs down trees and carries them onto power lines.”
Meteorologists who spoke to WIRED say it’s still too early to say exactly how this weekend’s storm will affect different regions of the country. But they say people in several states should start thinking ahead to the weekend and next week and pay attention to more up-to-date forecasts from local trusted sources over the next few days.
There is still a lot of uncertainty about how the storm will form and what impact it will have on specific areas. “We know this storm system is completely waterlogged,” says Matthew Cappucci, an atmospheric scientist and meteorologist with the Washington Post’s Capital Weather Gang. Cappucci says the system picked up a lot of moisture from the Gulf of Mexico, guaranteeing some form of precipitation for much of the southern and eastern United States. However, there is still uncertainty about how other atmospheric features will shape the storm. This includes a frigid vortex of low-pressure air in the upper atmosphere (called, in meteorological parlance, an upper-level low) that is forming over the Pacific Ocean, the formation of which will facilitate determine how and where precipitation will fall.
“A large swath of the southern and eastern United States will see more than 2 inches of water,” Cappucci says. “Whether it be rain, snow, sleet, freezing rain or a combination thereof remains a wild card.”
National Weather Service announcements are not winter weather warnings, Sublette argues, but “news”; forecasts will become more detailed as the storm intensifies. However, there is enough data available to start preparing for worst-case scenarios. Many regions likely to be hit by the storm are historically ill-prepared for extreme winter conditions: the 2014 ice storm that ripped through parts of Georgia and South Carolina left some areas without power for several days. This storm will hit just weeks before the five-year anniversary of the Texas winter storm that caused a two-week power outage and ultimately killed almost 250 people.