A strong ridge of high pressure formed over the eastern United States on Monday, June 24, and lasted through midweek. The hot afternoon temperatures, reaching as much as ten degrees above normal, combined with high humidity to produce dangerous heat index values. The extreme heat persisted on Tuesday and Wednesday, with maximum temperatures exceeding 100 degrees and heat indices approaching 110 degrees because of the humidity. The National Weather Service (NWS) station at Greenville-Spartanburg International Airport recorded new daily maximum temperatures of 98 degrees on Tuesday and 99 degrees on Wednesday, breaking previous records of 97 degrees set in 1996 and 1981, respectively. Heat index values hit 108 degrees in Columbia, 107 degrees in Charleston, and 106 degrees in Greenville.
On Tuesday, June 24, the South Carolina Emergency Management Division and Irmo Fire Department reported that twenty people were struck or electrocuted when lightning from a nearby thunderstorm hit Lake Murray Public Park in Lexington, SC. Eighteen individuals were taken to local hospitals with what were considered life-threatening injuries. The atmosphere was very unstable on Wednesday, and thunderstorms developed into a multi-cellular cluster that moved southward across the state late Wednesday into Wednesday evening. Hailstones up to golf ball size were reported in parts of the Midlands and Upstate, along with widespread reports of wind damage. The station at Donaldson Field Airport in Greenville County recorded a wind gust of 55 mph Wednesday evening, and the station at Pinopolis reported a wind gust of 62 mph.
Although temperatures were slightly cooler on Thursday, with highs in the low to mid-90s, the hot and humid weather persisted throughout the weekend. Peak heat index values exceeded 100 degrees but remained below heat advisory thresholds for the NWS county warning areas. The environment stayed unstable throughout the rest of the period due to features aloft and at the surface, which led to scattered showers and thunderstorms developing each afternoon and evening, some of which were strong to severe.
(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 | Trace | 20.56 | -3.1 |
| Greer Airport | 1.04 | 25.08 | 0.8 |
| Charlotte, NC Airport | 0.31 | 18.79 | -2.8 |
| Columbia Metro Airport | 1.04 | 23.70 | 2.1 |
| Orangeburg 2 (COOP) | 1.15 | 27.39 | 3.1 |
| Augusta, GA Airport | 0.11 | 22.95 | 0.8 |
| Florence Airport | 0.90 | 18.20 | -2.2 |
| North Myrtle Beach Airport | 0.56 | 16.40 | -3.0 | Charleston Air Force Base | Trace | 16.62 | -5.8 |
| Savannah, GA Airport | Trace | 20.90 | -2.1 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Columbia: 81 degrees. Barnwell: 77 degrees. Mullins: 74 degrees.
The primary rain event during the period occurred on Wednesday evening, while isolated and scattered showers and thunderstorms were observed daily. Rainfall totals from Wednesday’s storms ranged from less than a tenth of an inch in portions of the Lowcountry and Upstate to three inches in the Midlands, especially in Calhoun, Fairfield, Kershaw, and Richland counties. Rainfall totals for the period ranged from Trace amounts along the coastal Lowcountry to over four inches of rain in Lancaster and York counties.
Even with the scattered and isolated rainfall during the period, the 14-day average streamflow values at many gauges across the state continued to record normal to above-normal levels. A few gauges in the headwaters of the Pacolet and Tyger rivers in the Broad River basin observed flows that were below normal. The river and tidal height gauges reported values below the action stage during the period.
