A stationary front lingered across the region on Monday, August 28, resulting in unsettled weather ahead of Hurricane Idalia that impacted the state during the middle of the week. Scattered showers and thunderstorms produced up to two inches of rain in the higher elevations of the Upstate, while areas south of Interstate 85 recorded less than a quarter of an inch of rain. Temperatures on Monday and Tuesday had highs in the upper 80s to low 90s and overnight temperatures in the low 70s.
On Wednesday, August 30, Hurricane Idalia made landfall along the Florida Big Bend coast near Keaton Beach at 7:45 AM, with maximum wind speeds of 125 mph. The hurricane moved through southeast Georgia and the South Carolina coast throughout the day and into early Thursday morning. The maximum recorded wind gust in the state was 66 mph, recorded in Beaufort, and there were five confirmed tornadoes, with two possible tornadoes. Widespread rainfall totals between three and eight inches were measured across the Coastal Plain, with isolated higher amounts observed in Hampton, Marion, and Orangeburg counties. The Charleston Harbor Tidal Gauge recorded astronomical high tides ranging from 7.29 feet and 7.70 feet MLLW on Monday and Tuesday, peaking at 9.23 ft MLLW on Wednesday. The higher tides caused moderate to major flooding in low-lying coastal areas and closed roads in the Charleston area due to saltwater flooding. Initial estimates indicate that Idalia produced a storm surge of between two and three and a half feet along the South Carolina coast.
Here is an Open-File Report on Idalia, prepared by our office: https://www.dnr.sc.gov/climate/sco/Publications/OFR-Idalia-2023.pdf
By Thursday morning, Tropical Storm Idalia had moved off the North Carolina coast, and a cold front pushed through the state. With high pressure in control, drier and cooler weather conditions prevailed through the long holiday weekend. Even with plenty of sunshine, maximum temperatures were up to five degrees cooler than average, with highs primarily in the mid-80s. The drier air was a welcome relief from oppressive heat indices during the previous periods and allowed overnight temperatures to drop into the mid- to upper-50s.
The tropics continued to be active, with Hurricane Franklin still out in the Atlantic and Tropical Storm Jose and Tropical Storm Katia quickly forming and dissipating in the eastern Atlantic.
(Note: The highest and lowest official temperatures and highest precipitation totals provided below are based on observations from the National Weather Service (NWS) Cooperative Observer network and the National Weather Service's Forecast Offices.)| Weekly* | Since Jan 1 | Departure | |
|---|---|---|---|
| Anderson Airport | 1.95 | 38.82 | 7.0 |
| Greer Airport | 2.31 | 44.42 | 10.1 |
| Charlotte, NC Airport | 2.79 | 35.51 | 5.3 |
| Columbia Metro Airport | 2.25 | 41.50 | 9.4 |
| Orangeburg 2 (COOP) | 4.27M | 46.54M | 10.5M |
| Augusta, GA Airport | 2.83 | 46.77 | 14.9 |
| Florence Airport | 3.92 | 37.42 | 5.7 |
| North Myrtle Beach Airport | 5.24 | 30.47 | -1.5 | Charleston Air Force Base | 2.94 | 35.52 | -1.3 |
| Savannah, GA Airport | 1.58 | 33.32 | -1.6 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: 76 degrees. Columbia: 78 degrees. Barnwell: 71 degrees. Mullins: 64 degrees.
Most of the rain during the period came from the passage of Idalia, which had been downgraded to a tropical storm when it moved through the state on Wednesday. The tropical system produced widespread rainfall totals between three and eight inches across most of the Coastal Plain, with localized higher amounts. Much of the Midlands and all the Upstate missed the heaviest rains from the storm, reporting weekly totals of less than two inches, with some parts of Greenville, Laurens, and Union counties recording less than half an inch of rain. The US Drought Monitor (USDM) was released on August 29, before Idalia’s rains, and depicted abnormally dry conditions (D0) across much of the Midlands and Pee Dee regions and moderate drought conditions (D1) in Lexington, Newberry, and Saluda counties in the Midlands and Chester, Chesterfield, Fairfield, Lancaster, and York counties.
With precipitation across most of the region, streamflow gauges reported increased flows. Those in the Coastal Plain recorded values that were above average, with a few gauges reporting stream flows that were much above normal, including the gauges on the Edisto River near Givhans Ferry and the Little Pee Dee River at Galivants Ferry. Two gauges in the state, the Catawba River at Rock Hill and Rocky Creek at Great Falls, reported below-average flows during the period. Due to the rainfall, some river height values in the Coastal Plain rose to minor and moderate flood stages. Idalia's persistent onshore flow and astronomically high tide produced above-normal tides along the South Carolina Coast, causing moderate to major flooding in low-lying areas.
