Weather conditions are forecast to improve this weekend over most of the Palmetto State; however, coastal flooding and rip currents are forecast for residents and visitors along the coast.
A cold front passed through much of the state late Thursday night. High pressure over the Great Lakes will supply cooler and less humid conditions over the weekend, but that same high will cause the pressure gradient -- the change in pressure over a distance -- to increase. In addition, the new moon phase recently passed and the perigee (when the moon is closer in its orbit to earth) are strongly favoring higher-than-normal tide cycles. This end result is a combination of strong northeast winds and favorable astronomical influences that are likely to cause more coastal flooding.
The tide gauge at Charleston Harbor is expected to reach moderate or major flood stage near the times of high tide (between 10 and 11 AM and PM) starting Friday evening, lasting through Sunday evening. In addition, the Fort Pulaski gauge near the Georgia/South Carolina state line is also forecast to reach moderate flood stage around 11 PM Saturday and 11 AM Sunday. Minor flooding is expected there at other tide cycles near midday and midnight starting Friday and lasting through Sunday.
Rough water conditions likely along the #SouthCarolina coast this weekend. Swimmers may encounter rip currents and rough surf. Strong NE winds and astronomical influences expected to cause moderate to major coastal flooding along #Lowcountry coast. Expect road disruptions. #scwx pic.twitter.com/pyTxISKjWr
— Ray Hawthorne (@ray_hawthorne) September 18, 2020
Major Hurricane Teddy in the open tropical Atlantic is forecast to pass near or east of Bermuda Sunday night and Monday morning. The official National Hurricane Center forecast then takes it northward toward Atlantic Canada by the middle of next week. Even though the storm will pass well east of South Carolina, it will have indirect effects. Teddy's large wind field will augment the effects of strong winds from the high pressure and astronomical influences. Long-period swell and rip currents are expected to reach the state's beaches and cause dangerous swimming conditions. The National Weather Service in Charleston said it may issue high surf advisories this weekend because of these factors.
The remainder of the state is expected to experience noticeably cooler and drier conditions with a gusty breeze.