The period started with an unsettled weather pattern that held through midweek as a frontal boundary stalled over the state. On Monday, July 19, tropical moisture dumped rain in portions of the Lowcountry, flooding roads and making them impassable in parts of Summerville in Dorchester County. Weather stations on the Isle of Palms and Sullivans Island recorded wind gusts of 40 to 45 mph from thunderstorms. With high moisture amounts in the atmosphere, extensive cloud cover kept high temperatures in the upper 70s to lower 80s across most of the state. The National Weather Service (NWS) station at the Columbia Metropolitan Airport set a new low maximum temperature record of 79 degrees, breaking the previous record of 85 degrees set back in 2001. The increased moisture led to heavy rain and produced flooding in Aiken and Lexington counties. Floodwaters blocked a portion of Highway 391 in Batesburg, undermined some railroad tracks, and closed roads in Monetta.
Typical summer-time weather continued through the remainder of the week, with scattered afternoon storms on Thursday and Friday and near-normal temperatures. A weak frontal boundary triggered strong storms on Thursday in parts of the Lowcountry. An outflow boundary produced strong winds that knocked a tree onto powerlines near Gifford in Hampton County. Heavy rain in Charleston closed roads near the Ashley River, including a portion of I-526, and caused street flooding in low-lying spots downtown.
An upper-level trough over the East Coast provided northwest flow over the state, helping funnel some of the smoke from the western wildfires into the Southeast through the end of the period. The smoke caused hazy conditions, despite mostly clear skies, and degraded air quality. In addition to the poor air quality, the northwest flow provided some drier air across the state. While conditions were mainly dry across much of the state on Saturday, a nearly stationary thunderstorm dumped copious amounts of rainfall in northern Spartanburg County, prompting flash flood warnings near Chesnee. The storm produced more than seven inches of rain, which caused numerous road closures in the area.
Another round of King Tides impacted the coast during the weekend. There were multiple reports of shallow saltwater flooding in downtown Charleston and low-lying areas along the entire South Carolina coast. The tidal gauge in the Charleston Harbor reached 7.49 ft mean lower low water (MLLW) on Friday evening, 7.27 ft MLLW Saturday night, and 7.05 ft MLLW late Sunday.
(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 | 2.29 | 25.43 | -1.5 |
| Greer Airport | 1.16 | 30.07 | 1.9 |
| Charlotte, NC Airport | 0.38 | 23.11 | -1.6 |
| Columbia Metro Airport | 2.37 | 25.37 | 2.4 |
| Orangeburg Airport | 2.44 | 25.37M | -0.1M |
| Augusta, GA Airport | 1.63 | 33.93 | 8.0 |
| Florence Airport | 0.25 | 26.86 | 1.6 |
| North Myrtle Beach Airport | 2.55 | 30.88 | 6.9 |
| Charleston Air Force Base | 0.86 | 29.43 | 1.5 |
| Savannah, GA Airport | 1.96 | 28.00M | -0.2M |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. |
4-inch depth soil temperature: Clinton: 80 degrees. Columbia: 81 degrees. Barnwell: 75 degrees. Mullins: 70 degrees.
Most of the state recorded over an inch of rainfall over the seven days, with widespread reports between two and three inches of rain. Portions of Aiken, Charleston, Lexington, Oconee, and Pickens counties observed up to six inches of rainfall. A CoCoRaHS observer near Chesnee in Spartanburg County measured a seven-day total of 9.19 inches, with 7.40 inches coming from one thunderstorm on Saturday. However, locations in the Pee Dee, including Chesterfield, Darlington, Florence, Kershaw, and Lee counties, missed out on the rain, recording less than a quarter of an inch. At the beginning of the period, areas in the Upstate that continued to report abnormally dry conditions (D0) per the United States Drought Monitor, but rainfall over the weekend eased some of the dryness.
With the recent rainfall across the region and the heavy rain during this period, many gauges reported slightly above normal streamflow values, including the Broad River at Alston, the Savannah River at Augusta, and the Lynches River at Effingham. During the period, rainfall in portions of the Midlands caused the river height at the North Fork of the Edisto near Orangeburg to briefly rise to minor flood stage before falling below the threshold.
