TLDR: Stormy day tomorrow on the GA/SC coast, with rain, high morning tide, and of most concern strong winds that will likely cause scattered power outages and light damage. Some tornado potential, so keep weather radios armed. In other words, inconvenient for sure, hazardous if you taunt it or are unlucky, but not generally dangerous.
First, for the official word, weather service offices produce a nice “weather briefing” that has a good, no drama one page summary during events like this. Here is the latest briefing from the WSFO Charleston (link to PDF, updates automagically), which covers from Darien GA northward to north of Charleston SC. The “big picture” is that a very strong storm system is moving across the US East Coast today and tomorrow. So what’s the selfish forecast? Here’s a few thoughts, but the summary above pretty much sums it up: strong winds, some rain but not likely to cause much flooding other than the usual spots when we get an inch or two of rain in a day.
The overriding concern for tomorrow is wind. The winds aloft are very strong in this system, and as it sweeps towards the coast the variable known as “Storm Relative Helicity” or SRH values are quite high. Here is the NAM-hires forecast for 2pm tomorrow afternoon:
Values over 100 are a concern, and over 250 worrisome – this system will likely have areas pushing 700 and up. The formation of supercells and “Quasi-Linear Convective Systems” (QLCS) with embedded tornadoes become possible, especially over 250, and the coastal GA/SC and inland areas will certainly be over 400, thus the tornado risk. Scary stuff, but important to realize that these are general guidelines and potential. It’s easy to play up the potential but there are other factors. The convective (thunderstorm) energy in a winter system like this isn’t as high, but is being watched for signs it could increase.
The bottom line on the tornado risk is to have a weather radio (we have had good luck with the Midland model wr-120, they are inexpensive – around $35 last I checked – and available from Best Buy, Walmart, and of course Amazon). You CANNOT rely on the sirens, especially in strong winds which carry the sound in weird ways, and the cell phone/app warnings can be delayed a couple minutes or given the potential for scattered outages and cell phone system problems, never. So shell out the $ for a weather radio for peace of mind and the best possible warning systems.
As for flooding, a few spots might see 2″ but most will be under that, so this isn’t a flash flood event. Right on the coast might see high water around high tide in the morning, from the official guidance:
At 9.5 ft MLLW, minor coastal flooding occurs. Flooding will begin to impact Shipyard Road to Burnside Island. Parts of Ft Pulaski National Monument will begin to flood, including several trails. Flooding will also begin to impact Tybee Island including Catalina Dr and Lewis Ave. In Bryan County, water could breach docks near Ft McAllister and flooding will impact portions of Mill Hill Rd. In Liberty County, flooding impacts the Halfmoon Landing area and Cattle Hammock Rd near Bermuda Bluff subdivision.
The bigger coastal flood risk is further north in Charleston. Nearshore area, some pretty high waves (10ft and up) and winds gusting to 50 knots are likely, so don’t go to the beach and yell at the storm or do a Lt. Dan re-enactment. For that matter, probably a good idea not to travel tomorrow afternoon by car either if you don’t have to, will be messy.
To sum up, a strong frontal system will bring some pretty strong, gusty winds to the region, maybe some strong thunderstorms with tornado potential. There will be some scattered power outages, unlucky folks might get some minor damage, keep your weather radios handy in case of a tornado. If you are in a warned area, know what to do – interior hallway or room away from windows, those in mobile homes/manufactured housing should have a plan. But we’ve seen this kind of blow several times over the last few years, it’s nothing like the tropical storms like Matthew, so with some common sense not nearly as scary as the upcoming elections.
Thank you so very much for the information,