On Monday, May 8, a surface high pressure shifted south of the area. A surface trough set up over the Mid-Atlantic, helping to increase moisture across the region, and widely scattered showers and thunderstorms developed during the evening. The warming trend from the weekend continued through the first part of the period. High temperatures on Monday reached the mid to upper 80s and low to mid-90s on Tuesday. With warm air in place, as a weak cold front moved south through the state late Tuesday afternoon, it triggered strong and severe storms in portions of the Lowcountry and Upstate. A cluster of storms in the Charleston Metropolitan Area caused quarter-sized hail and strong winds. The Charleston Harbor Tidal Gauge station recorded a 75-mph wind gust, and additional sensors recorded wind gusts between 45 and 65 mph. Another thunderstorm complex near Greenville produced heavy rain and hail for a prolonged period near Interstates 85 and 385. There were multiple reports of hail sizes between pea and golf-ball sized, with one hailstone measuring 2.25 inches.
Conditions on Wednesday were drier, and temperatures were near average as the front pushed south of the state. High temperatures were in the upper 70s in the Upstate to low 80s across the rest of the state. On Thursday, conditions were seasonable despite the southeast flow ushering some moisture back into the region as high pressure moved offshore. Lifeguards reported strong rip currents along Hilton Head Island on Friday afternoon. Moisture continued to increase across the area, and isolated showers and thunderstorms developed during the late afternoon and evening hours. Highs on Friday reached the mid-80s, as another warming trend started that would continue through the remainder of the period.
Over the weekend, a backdoor cold front slowly approached the state, causing an unsettled weather pattern. Scattered showers and thunderstorms developed both Saturday and Sunday evenings, with highs in the upper 80s and humid conditions. On Sunday evening, a waterspout was observed on the southeast side of Lake Moultrie.
(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 | 0.57 | 22.32 | 4.9 |
| Greer Airport | 0.57 | 26.24 | 7.9 |
| Charlotte, NC Airport | 0.16 | 17.80 | 1.9 |
| Columbia Metro Airport | 0.16 | 19.31 | 4.6 |
| Orangeburg 2 (COOP) | 0.29 | 18.50 | 1.9 |
| Augusta, GA Airport | 0.41 | 23.05 | 7.4 |
| Florence Airport | 0.00 | 16.11 | 2.3 |
| North Myrtle Beach Airport | 0.15 | 12.09 | -1.7 | Charleston Air Force Base | 0.38 | 12.50 | -1. |
| Savannah, GA Airport | 0.24 | 13.77 | -0.6 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: 71 degrees. Columbia: 73 degrees. Barnwell: 69 degrees. Mullins: 65 degrees.
Rainfall was sparse across the state, with much of the state recording no rain or totals of less than half a quarter of rainfall during the period. Only locations under the spotty shower and thunderstorm activity recorded totals of over half an inch of rain. A couple of CoCoRaHS observers in Charleston and Greenville counties measured over two inches of rain from the intense storms on Tuesday evening. Due to the lack of rain, the abnormally dry (D0) conditions were expanded to reflect emerging impacts in the Lowcountry and Pee Dee regions on the most recent United States Drought Monitor map.
The 14-day averages for most stream flow values in the state's watersheds remained above average, despite the lack of widespread rain. Rain from previous periods had moved through the state’s watersheds, and river heights remained below the action stage.
