Traffic into downtown Charleston is nearly impossible. The Crosstown is closed and it’s not likely to reopen for a little while. Stalled cars litter the streets-turned-rivers downtown. Josh Marthers at WCBD captures the flooding situation well. I also highly recommend watching traffic tweets and pictures (and there are some good ones) on Collecta.

And as bad as this morning was, we haven’t seen the worst of it. This morning’s Day 1 Convective Outlook from the Storm Prediction Center continues the “slight risk” for severe weather in Charleston, and this could be upgraded to a “moderate risk” later today, especially if any sunshine peeks through and adds more fuel to the fire. The storm system which is expected to wreak havoc on us later this evening has already dropped several tornadoes in the Florida panhandle, and there is a good possibility we may see at least one or two tornadic cells later today in the Lowcountry. Straight-line damaging winds continue to be the primary threat from this system, though.

There’s a good shot that we’ll have a tornado watch in effect by 3PM today. Keep an eye to Twitter as the day progresses with updates from NWS and SPC. We’ll announce watches and warnings there as they happen.

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.

Later Wednesday, this storm system will bring along with it a favorable setup for severe weather — a bit unusual for December, but certainly not unprecedented. The entire SC coastal area is in a “slight risk” of severe weather for Wednesday. Damaging winds, hail, and tornadoes cannot be ruled out. Plan accordingly for your Wednesday if you are traveling. We’ll keep an eye on things and update as the forecast becomes more clear.