On Monday, August 29, easterly flow helped support scattered showers and thunderstorms. Heavy rain, with rain rates up to three inches in 90 minutes, caused numerous road closures in Charleston, Colleton, and Dorchester counties. Temperatures were cooler than usual in the eastern half of the state, where rain fell, and slightly warmer than average in the Upstate. The National Weather Service (NWS) station at the Greenville International Airport recorded a high of 90 degrees, while the station at the Charleston International Airport only reached a high of 78 degrees. An upper-level trough and cold front approached the area on Tuesday, triggering isolated showers and thunderstorms across the state. Highs were in the upper 80s to low 90s, with overnight lows in the lower 70s. The weak cold front moved through the state by the middle of the workweek before it stalled near the coast. Drier air then spread over the region, bringing near normal temperatures and lower humidity.
The front stalled off the coast on Thursday, September 1, the official start of meteorological Fall, and an upper-level low helped enhance rain chances across the region. A waterspout was spotted off Folly Beach on Thursday morning, and the unsettled weather conditions were favorable for the formation of waterspouts throughout the period. Heavy rain caused the closure of many roads in the Charleston area, including flood-prone areas on Lockwood Avenue and Meeting Street in downtown Charleston. Lightning caused two structural fires on Johns Island and one in West Ashley, and one person was injured after being struck by lightning near the ACE Basin National Wildlife Refuge. With the frontal boundary still off the coast on Friday, an additional round of thunderstorms developed in the Lowcountry. Another person was injured after being struck by lightning on Hilton Head Island; three other individuals standing nearby were knocked down by the jolt but were uninjured.
There was still plenty of moisture across the region over the weekend, and heavy rain in the Upstate on Saturday prompted flash flood warnings in Oconee and Pickens counties. Numerous roads were covered or closed due to water near Westminster, and a personal weather station near Oakway recorded over eight inches of rain in 12 hours. Another frontal boundary moved southward on Sunday, increasing the chance for showers and storms across the state.
(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 | 1.12 | 24.89 | -7.1 |
| Greer Airport | 0.29 | 36.37 | 2.0 |
| Charlotte, NC Airport | 0.37 | 28.50 | -1.8 |
| Columbia Metro Airport | 0.22 | 30.23 | -2.0 |
| Orangeburg 2 (COOP) | 1.84s | 39.77s | 3.7s |
| Augusta, GA Airport | 2.78 | 38.52 | 6.6 |
| Florence Airport | Trace | 26.97 | -4.9 |
| North Myrtle Beach Airport | 0.27 | 35.08 | 2.9 | Charleston Air Force Base | 3.66 | 37.39 | 0.4 |
| Savannah, GA Airport | 3.22 | 29.11 | -6.0 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: 77 degrees. Columbia: 80 degrees. Barnwell: 75 degrees. Mullins: 71 degrees.
Most of the area along and east of the Interstate 77 corridor and parts of the northern Pee Dee region reported rainfall totals of less than a tenth of an inch during the period. Some of these areas have measured less than 50 percent, or three to four inches below normal, of their usual rainfall for August. Due to the stalled front along the coast, parts of the Lowcountry recorded more than two inches of rain, with some CoCoRaHS observers measuring more than five inches during the period. In the Upstate, areas of Oconee and Pickens counties saw over five inches of rain, causing flash flooding near Westminster. Despite portions of the Upstate receiving rain during the period, the abnormally dry (D0) and moderate drought (D1) conditions continued to expand due to the lack of widespread precipitation.
The streamflow gauges in the headwaters of the Santee watershed continued to decline due to the lack of rain, with most of the reported streamflow values much below average. Those that recorded normal flows were on the lower end of those conditions. The gauges on the Congaree River near Columbia recorded 14-day average values that were much below normal. Elsewhere, gauges in the ACE and Pee Dee watersheds measured average streamflow values. All the state’s rivers observed heights below the flood stage.
