Wednesday: Slight risk of severe weather, high probability of damaging winds

The Storm Prediction Center has just issued its Day 1 Convective Outlook, placing the Charleston area in a slight risk for severe weather. Currently, forecasters are pegging the severe event to take place in the late afternoon and into the evening hours. Primary threats are widespread damaging winds as well as the possibility of tornadoes, especially along the coastal regions.

Currently, this is the thinking (or something like it) on Wednesday’s event:

  • 3AM – midday: Heavy rain with embedded thunderstorms associated with a warm front will soak the Lowcountry. The timing of the rain will line up with an already abnormally high tide at 7am. Enhanced with a brisk onshore flow, coastal areas including downtown Charleston could see potentially significant flooding. A Coastal Flood Warning goes into effect at 4am through 11am.
  • Midday – ~2-3 PM: Break in the action as the warm front lifts north, but before the cold front’s squall line reaches the coast. There’s a possibility that the sun may come out during this time; any sunshine could significantly destabilize the atmosphere further and thus enhance the intensity of severe weather.
  • 3 PM – Evening: Cold front makes its move on the Lowcountry. Squally thunderstorms with strong, damaging wind likely. Supercells also are a possibility; those storms can contain downbursts and tornadoes. Heavy rain also is expected, though the flood threat is not expected to be as pronounced in the evening. Activity will likely continue after sunset; be especially aware of rapidly changing conditions after dark because it will be much harder to see what’s happening.
  • Thursday: Conditions gradually abate themselves as the front moves through; rain tapers off through Thursday.

The takeaway: The morning and afternoon commutes will likely be quite nasty. Allow extra time during your commute, and if you encounter a flooded area downtown in the morning, turn around! It takes relatively little water to stall out a vehicle. Streets such as Rutledge and Ashley Avenues, Jonathan Lucas, Bee Street, the Crosstown, East Bay Street, Market Street, and others could prove impassable. Have alternate routes ready to go. Other coastal communities, including Folly Beach and Isle of Palms, may also see significant flooding problems in the morning.

Keep an eye here or to @chswx for updates throughout the day.