While all eyes are on the developing tropical cyclone near the Bahamas, a surge of moisture ahead of what could be Imelda will result in heavy rainfall and blustery conditions, whether or not the tropical entity ventures anywhere close to the Palmetto State.
Forecast models show communities primarily south of Interstate 20 picking up 1–3 inches of rainfall through Tuesday, with lighter amounts the farther you travel from the coastline.
Locales that could see the heaviest rainfall include Charleston and Myrtle Beach, where rain coinciding with periods of high tide could lead to minor flooding.
Between Tuesday and Thursday, whatever becomes of the tropical cyclone will make its closest approach to South Carolina, meaning the threats for heavy rainfall, erosion and coastal flooding will increase. However, the exact impacts will depend on its track.
Due to two scenarios that are in play, both state and local municipalities have issued states of emergency, and officials are preparing for the worst while hoping for the best.
"As this storm approaches our coast, I am issuing a State of Emergency to ensure Team South Carolina is able to access and deploy the resources and personnel needed to prepare for and respond to this storm," said Governor Henry McMaster. "While the storm's arrival, speed and intensity remain hard to predict, we do know that it will bring significant wind, heavy rainfall and flooding across the entire state of South Carolina. We have seen this before. Now is the time to start paying attention to forecasts, updates and alerts from official sources and begin making preparations."
Scenario #1: Cyclone ventures close to Southeast coastline
A scenario that many models depicted just a day or two ago now has the fewest members suggesting it.
If the cyclone were to venture either over or close to the coastline, high-end tropical storm or even minimal hurricane conditions would be possible throughout the Lowcountry and the Grand Strand, with rainfall accumulations likely over a foot.
Additionally, tidal levels would likely reach at least 4 to 5 feet above normal, causing extensive coastal flooding.
This scenario would require the issuance of either Tropical Storm or Hurricane Watches or Warnings, along with storm surge alerts.
Due to the presence of Category 5 Hurricane Humberto in the central Atlantic and a nearby frontal boundary, both are expected to act as mechanisms to keep what will be known as Imelda from ever reaching the coast.
Scenario #2: Cyclone stays 100–300 miles off the coast
Most computer forecast models show what would become Imelda staying safely offshore, but with all the weather features at play, much of the week will still be rather squally.
Under this scenario, 1-2 inches of rainfall will be likely in the Upstate and along the I-85 corridor, while 2-4 inches of precipitation will be possible along I-20 and as much as 4-8 inches rain east of I-95 and along the coast.
Wind gusts would likely remain below the threshold for Tropical Storm Watches or Warnings, but breezy conditions are still expected at times.
Due to rainfall and higher-than-normal tides, Flood Watches and coastal flood alerts would likely be issued by local National Weather Service offices.
Most of South Carolina is dealing with unusually dry conditions, so the added precipitation could be welcome news for some communities.
With both Tropical Depression Nine and Hurricane Humberto spinning in the Atlantic basin, surf conditions are expected to remain rough through the week, with a high risk of life-threatening rip currents.
According to the National Hurricane Center, more than 10% of all tropical weather-related fatalities occur from rip currents.