The main weather story for the week was unstable atmospheric conditions, which led to the development of strong to severe afternoon and evening thunderstorms. Temperatures during the period were five to ten degrees above normal, with the majority of observed low temperatures in the low to mid-70’s, and the daytime highs reaching the low to mid-90’s.
The high pressure that moved into the area over the weekend remained in control of the weather at the beginning of the week, limiting the shower and thunderstorm activity and creating pleasant weather on Monday, August 12. By Tuesday morning, a cold front began to approach the Southeast U.S., causing temperatures and rain chances to increase slightly. With the return of southerly flow across the region, the increased moisture across the state helped create high heat index values, pushing 105 degrees across much of the state. During the afternoon, scattered storms developed in parts of the Piedmont and Upstate. The South Carolina Highway Patrol (SCHP) reported downed trees near Lowrys in Chester County, and a storm spotter observer reported trees down in York County. Thunderstorms that developed in Spartanburg County downed trees and power lines in Landrum.
Ahead of the cold front, the National Weather Service (NWS) station at the Columbia Metropolitan Airport measured a morning low temperature on Wednesday of 81 degrees. However, the afternoon thunderstorms cooled the temperature later that evening to 79 degrees, which replaced the previous record high minimum temperature of 77 degrees set in 2016. Another round of hot temperatures and humid conditions pushed heat index values between 105 and 110 degrees in the Midlands and Pee Dee regions. As the cold front entered the area, the combination between the warm moist air and the cold front caused a few severe thunderstorms and produced strong winds and heavy rainfall. Quarter-to half-dollar-sized hail was reported in the Ladson area in Berkeley and Dorchester counties, and heavy rain created localized flooding in the area, making some roads impassable. SCHP reported trees down along I-95 in Colleton County, and additional reports of downed trees down in Hendersonville and Cottageville. Thunderstorms in Beaufort and Jasper counties produced strong winds; half-dollar sized hail was reported in Beaufort; and heavy rains flooded roads in Dale.
The weak frontal boundary lingered across the region, providing a focus for scattered showers and isolated severe thunderstorms. Early morning showers on Thursday, August 15, set up in parts of the Midlands, bringing some rain to portions of the state impacted by the continued dry conditions. By the early evening, slow-moving thunderstorms formed along a line across Florence, Williamsburg and Horry counties. The storms produced frequent lightning, which started a structural fire in Conway, causing minimal damage to the dwelling, and heavy rainfall. A CoCoRaHS observer near Conway reported a 24-hour rainfall total ending Friday morning of 7.48 inches. The frontal boundary stalled across the Midlands and helped initiate isolated diurnal convection during the weekend.
On Saturday, heavy rain was reported in Beaufort County, with three to five inches of rain falling between midnight and noon. During the afternoon, additional thunderstorms developed over parts of the Lowcountry, causing heavy rain in parts of Berkeley and Beaufort counties, and lightning caused fire damage to two structures in Port Royal. In the Upstate and Midlands, thunderstorms knocked down trees near Cross Hill in Laurens Count and Carlisle in Union County. A severe thunderstorm formed over Newberry County and produced heavy rain, strong winds and frequent lightning. A weather station at the Newberry Sheriff’s Office reported a peak wind gust of 68 mph from the storm, and multiple reports of golf-ball-sized hail came in from the area northeast of Newberry. The weather on Sunday continued to be unsettled as strong thunderstorms developed during the late afternoon in parts of the Piedmont and Upstate. Quarter-sized hail was reported in Taylors, wind damage occurred in Oconee near Walhalla and near Cowpens in Spartanburg County. In Cherokee County, storms caused tree damage near Kings Mountain State Park and quarter-sized hail near Blacksburg.
(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 | 0.20 | 25.03 | -2.9 |
| Greer Airport | 1.20 | 34.60 | 3.9 |
| Charlotte, NC Airport | 1.70 | 34.79 | 7.9 |
| Columbia Metro Airport | Trace | 24.38 | -5.5 |
| Orangeburg Airport | 0.04 | 17.09 | -14.2 |
| Augusta, GA Airport | 3.07 | 28.66 | -0.5 |
| Florence Airport | 2.56 | 28.92 | 0.6 |
| North Myrtle Beach Airport | 6.04/td> | 31.00 | -0.9 |
| Charleston Air Force Base | 3.31 | 29.90 | -2.5 |
| Savannah, GA Airport | 0.33 | 27.77 | -3.9 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. |
4-inch depth soil temperature: Clinton: 81 degrees. Columbia: 85 degrees. Barnwell: 77 degrees. Mullins: 74 degrees.
The majority of the rainfall over the seven-day period fell in coastal portions of the Lowcountry and Pee Dee regions. Locations in Beaufort, Charleston, Georgetown and Horry counties reported up to five inches of rain, though some CoCoRaHS observers reported half of those totals coming from one event. Due to localized thunderstorms, isolated amounts of two to three inches fell in the Midlands and Upstate, with less than an inch recorded for the majority of the state west of the Interstate 95 corridor. River levels across parts of the state remained low, and streamflow values continued to drop, with many streams and rivers reporting flows below normal for this time of year. Allendale and Hampton counties in the Lowcountry and Dillon, Florence, Horry and Marion counties in the Pee Dee continue to be the driest areas of the state, reporting less than twenty inches since the beginning of the year. Totals of over thirty inches in portions of Beaufort, Charleston and Colleton counties were confined to the coast, while interior locations within the counties measured lower amounts. Although rainfall totals in the Upstate over the last 30 days are below normal, the year-to-date rainfall totals in the Upstate remained near to above normal for this time of year, with more than twenty-five inches reported at many locations and over fifty inches in some of the more mountainous areas.
Charleston Harbor (CHTS1): 85.3 degrees.
Capers Nearshore Buoy (Station 41029): 84.0 degrees.
Fripps Nearshore Buoy (Station 41033): 84.2 degrees.
