The period started with and was dominated by Hurricane Isaias. On Monday, August 3, Tropical Storm Isaias strengthened into a Category 1 hurricane as it moved northward along the South Carolina coast. The storm made landfall, shortly after 11 PM near Ocean Island Beach, North Carolina, and raced across the Eastern Seaboard, causing heavy rain and tropical storm-force winds through the New England area. A CoCoRaHS observer recorded 6.80 inches near Pawley’s Island, and some locations broke their daily rainfall records, including the 3.31 inches reported at the National Weather Service (NWS) station in Myrtle Beach. Maximum wind speeds across South Carolina ranged from 45 to 55 mph, with the most torrential rain falling across coastal Charleston County into the Pee Dee region. There was one confirmed tornado in South Carolina; a short-lived EF0, with maximum winds of 80 mph, near Murrells Inlet. Storm surge from Isaias caused significant beach erosion and breached and cut dunes in Georgetown and Horry counties. The Springmaid Pier gauge reached 10.18 ft. MLWW during high tide, which is the third-highest level on record at the location, behind Hurricane Hugo in 1989 and Hurricane Matthew in 2016.
As the storm continued to pull away from the area on Tuesday, dangerous rip currents formed due to the lingering swells from Isaias. The cloudy skies and rain on Monday gave way to drier air over the region, though it would be short-lived as an upper-level trough west of the area would stream moisture back into the Carolinas by midweek. The increased humidity kept overnight temperatures warmer than normal, and the NWS Beaufort station recorded a high minimum temperature of 81 degrees on Wednesday morning, breaking the previous record of 80 degrees set back in 1980.
Heading into the end of the week, a weak front stalled and lingered across Georgia and the Carolinas, creating an environment conducive for the development of scattered thunderstorms through the remainder of the period. Some of the storms produced locally heavy rainfall, and a few reached severe limits, with damaging wind. On Thursday, CoCoRaHS and storm spotters in the Midlands reported between four and five inches over three hours. A severe thunderstorm sparked a fire in a building and tree on Friday near Green Sea in Horry County, while storms in the Midlands produced a large amount of lightning, striking an individual in Blythewood in Richland County. Additional moisture, showers, and thunderstorms produced rainfall amounts of half an inch or higher in some localized parts of the state. Over the weekend, strong storms caused minor tree damage in portions of the Lowcountry and Piedmont, and the NWS station at Beaufort MCAS recorded a wind gust of 48 mph.
(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 | 1.23 | 42.44 | 15.6 |
| Greer Airport | 0.49 | 50.50 | 21.1 |
| Charlotte, NC Airport | 0.68 | 34.71 | 9.1 |
| Columbia Metro Airport | 0.99 | 41.17 | 12.8 |
| Orangeburg Airport | 1.77 | 28.80 | -0.8 |
| Augusta, GA Airport | 3.13 | 41.44 | 13.6 |
| Florence Airport | 1.99 | 43.48 | 16.6 |
| North Myrtle Beach Airport | 5.04 | 34.80 | 5.0 |
| Charleston Air Force Base | 3.11 | 33.10 | 2.7 |
| Savannah, GA Airport | 1.33 | 34.04 | 4.3 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. |
4-inch depth soil temperature: Clinton: 81 degrees. Columbia: 82 degrees. Barnwell: 77 degrees. Mullins: 71 degrees.
Much of the rain that fell during the period came from Hurricane Isaias as it moved along the South Carolina coast. Widespread portions of the Pee Dee region and coastal areas of the Lowcountry reported between three and seven inches of rainfall from the storm. Elsewhere, showers and thunderstorms were isolated, and areas that received measurable precipitation were under slow-moving storms, including localized amounts up to four inches in parts of the Midlands and Upstate. Pockets of two-plus inches dotted the state, mainly from afternoon convective and sea breeze storms. The year-to-date rainfall totals are near- to above-normal values across much of the state. The rainfall helped ease some of the dry conditions in small areas of the Lower Savannah River Basin and Lowcountry. However, the lack of rainfall and warm temperatures led to reports of decreasing surface water supplies and drying topsoil in fields.
The USGS streamflow data across the state show most of the gauges are reporting normal to above-normal values at 14- and 28-days. Streamflows in the regions that received more substantial amounts of rain saw the streamflow values rise, while those gauges in areas that missed out on any rainfall during the period have dropped off.
