A weak surface front over the region caused an unsettled weather pattern on Monday, August 12, which helped trigger showers and thunderstorms across portions of the Coastal Plain and Upstate during the late afternoon and early evening. Some storms produced heavy rains, and localized rainfall amounts of over two inches were reported by Tuesday morning in Greenville County. The frontal boundary lingered over the state, leaving increased rain chances, especially for the Midlands and Coastal Plain, through Wednesday before slightly drier air moved into the region. Maximum temperatures during the first part of the period were cooler than usual, with highs in the mid to upper 80s.
By Thursday, high pressure was centered over the Mid-Atlantic, providing dry conditions over most of the state and a slight chance of rain over isolated parts of the Upstate. Low temperatures on Thursday morning were in the mid-to-upper 60s, and highs reached the upper 80s by mid-afternoon. The dry conditions continued through Friday, though an approaching cold front helped trigger some isolated showers and thunderstorms, and temperatures were near normal for the rest of the period.
In the Atlantic, Hurricane Ernesto passed well to the east of the U.S. East Coast, directly impacting Bermuda on Saturday and Sunday but causing dangerous rip currents, high swells, wave heights, and rough surf conditions along the South Carolina coast over the weekend.
(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 | 0.29 | 34.76 | 5.0 |
| Greer Airport | 1.68 | 36.24 | 4.1 |
| Charlotte, NC Airport | 0.68 | 34.54 | 6.4 |
| Columbia Metro Airport | 1.64 | 39.70 | 9.7 |
| Orangeburg 2 (COOP) | 0.71 | 36.53 | 2.9 |
| Augusta, GA Airport | Trace | 32.91 | 3.3 |
| Florence Airport | 0.00 | 35.91 | 7.7 |
| North Myrtle Beach Airport | 2.35 | 38.30 | 10.0 | Charleston Air Force Base | 0.03 | 44.30 | 11.1 |
| Savannah, GA Airport | 0.42 | 42.45 | 10.3 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: Not Available. Columbia: 83 degrees. Barnwell: 77 degrees. Mullins: 72 degrees.
Widespread rainfall totals during the period in the Upstate ranged from less than half an inch of rain in Abbeville, Greenwood, and McCormick counties to up to two inches in parts of Greenville and Spartanburg counties. Much of the Midlands reported about half an inch of rain, though Newberry County areas reported over three inches of rain. Many Lowcountry and Pee Dee locations recorded less than a quarter of an inch of rain, though areas near the Grand Strand and Charleston saw higher totals. The heavy rainfall from Tropical Storm Debby was reflected in changes to the U. S. Drought Monitor map released on Thursday, August 15. Two category improvements were seen across the Midlands and Pee Dee regions, with abnormally dry conditions (D0) lingering in a small portion of the Pee Dee region, which had reported D3 conditions at the end of July. Most of the Upstate recorded less than an inch of rain from Tropical Storm Debby, and D0 conditions continued across the Upper Savannah.
Rainfall from Tropical Storm Debby kept the 14-day average streamflow at gauges across much of the state, especially those within the eastern half of the state. Many gauges measured flows much above average or high, over 500 percent of normal. However, with the lack of rain and persistent drought conditions in portions of the Upper Savannah River Basin, the 14-day average streamflow values remained below average. River heights in the ACE Basin crested and started to fall slowly during the period, while those in the Pee Dee watershed continued to rise, where heavy rainfall moved from the headwaters and through the watersheds.
