Idalia emerges over Atlantic waters; coastal flooding continues, tropics not slowing down

Major coastal flooding reported in downtown Charleston Wednesday evening; minor to moderate flooding possible today into North Carolina’s Pamlico Sound

Idalia quickly moved back into the Atlantic off the coast of Myrtle Beach overnight, but not before delivering major coastal flooding to parts of the Palmetto State, including in downtown Charleston where floodwaters reached nearly 3.5 feet, the fifth highest water level observed at a tidal gauge with records going back 100 years.

Moderate to borderline major flooding is anticipated into this weekend along local Low Country and Coastal Plain rivers from the 6-10 inches of heavy rainfall left behind by Idalia.

Idalia will continue eastward away from the U.S. today, but will then slow down and meander southward near Bermuda into the weekend. The storm isn’t expected to restrengthen for the next few days.

While models are in decent agreement with Idalia moving northeast for the early part of next week, the forecast gets murky by mid-week as high pressure rebuilds to the north and attempts to force the circulation back west.

For now, very few models take it far enough south and west to be a problem again for Florida (and those that do keep it very weak), but we’ll follow the trends for the mid-Atlantic and northeast. With such high uncertainty, it’s something to monitor for these areas.

Franklin accelerating away from Bermuda and weakening

Franklin is wrapping up its 11-day journey through the Atlantic this week, which began south of Hispaniola last Monday. The hurricane is moving quickly away from Bermuda, where it made its closest point of approach yesterday, and is on a steady weakening trend.

Dangerous surf and rip currents propagating far away from Franklin will continue today into Friday along the U.S. mid-Atlantic and northeast coastlines.

Jose forms, Gert trying to mount a comeback, and Katia on deck

Tropical Depression Eleven strengthened into Tropical Storm Jose early Thursday morning over the central Atlantic. Jose is expected to remain weak and eventually get pulled northward and absorbed by Franklin’s circulation over the North Atlantic this weekend.

Due west of Jose are the remnants of Tropical Storm Gert, which formed briefly several hundred miles east of the Lesser Antilles last Monday. The system is trying to stage a comeback, but if it reforms, it should be short-lived, as hostile upper-level winds increase over the weekend. The system is no threat to land.

In the eastern Atlantic, Invest 94L near the Cabo Verde Islands shows signs of organization. Development appears likely and a tropical depression or storm is expected to form by the weekend. The system will quickly curl northward into the eastern Atlantic next week. If it’s named, it will likely be Katia.

Watching another tropical wave moving into the Atlantic this weekend

Low pressure tracks through next Wednesday from the European ensemble modeling system. The disturbance set to emerge off the coast of Africa this weekend is forecast to move generally westward into early next week. Credit:

Another vigorous tropical wave is set to move off Africa by early weekend. While still early, some of our better computer models are bullish on development into next week.

With guidance in agreement keeping high pressure firmly in place to the north, the system will maintain a westward trajectory for some time, so we’ll keep an eye on it. NHC isn’t even mentioning it in their outlooks yet, so we have plenty of time to monitor.

Most active hurricane season through August since 2012

Despite the strengthening El Nino in the eastern Pacific, the Atlantic has been on a tear so far in 2023.

To date (through August), the Atlantic has recorded two Category 4 hurricanes and the most activity (as measured by Accumulated Cyclone Energy or ACE) since 2012. Though El Nino may have a greater effect deeper into the season, it’s a remarkable statistic considering the extremely busy hurricane seasons of the past decade.

September – the peak month of the Atlantic hurricane season – arrives tomorrow.

About the Author:

Michael Lowry is Local 10's Hurricane Specialist and Storm Surge Expert.