A cold front stalled off the southeast coast on Monday, May 5, and Tuesday, May 6, producing isolated showers over the eastern half of the state. Still, the conditions remained mainly dry. Behind the front, cooler and drier air filtered into the region, with high temperatures in the upper 70s to lower 80s. Moisture and clouds returned to the region on Wednesday as low pressure formed and moved along the stalled front, resulting in scattered showers that developed during the late afternoon. Temperatures were still slightly cooler than normal, with highs five to ten degrees below normal.
On Thursday, the weak, stalled front was positioned off the coast, while a warm front lifted through the state, triggering strong to severe thunderstorms. Reports of hail ranging from penny-sized to golf ball-sized were received in portions of Beaufort, Edgefield, Lancaster, Orangeburg, and York counties late Thursday into early Friday morning, due to increased moisture and the potential for thunderstorms. A cold front approached the state on Friday, and isolated thunderstorms produced a 42-mph wind gust in Berkeley County. A Weatherflow station on James Island measured a 39-mph wind gust, while a 40-mph gust was recorded at the National Weather Service station at the Charleston International Airport.
The unsettled pattern and heavy rainfall continued over the weekend, as a cold front stalled across southern Georgia and a low-pressure system developed along the Gulf Coast. Flooded roads were reported near Port Royal in Beaufort County, and a 3-foot-wide and 6-foot-deep sinkhole was reported on McPhersonville Road in Beaufort County. Lightning struck a home near Bluffton on Saturday. Several roads in downtown Charleston were closed, including Huger Street, Meeting Street, and King Street, due to over two inches of rain falling across the city in just five hours on Sunday morning. Temperatures were up to fifteen degrees cooler than normal, due to increased cloudiness, with multiple new record low maximum temperatures broken, as some temperatures did not rise above the 60s.
(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 | 0.72 | 14.70 | -3.0 |
| Greer Airport | 0.89 | 16.79 | -1.1 |
| Charlotte, NC Airport | 1.58 | 12.51 | -3.1 |
| Columbia Metro Airport | 2.28 | 14.29 | -0.1 |
| Orangeburg 2 (COOP) | 3.76 | 15.07 | -1.2 |
| Augusta, GA Airport | 1.81 | 13.32 | -2.1 |
| Florence Airport | 1.89 | 11.50 | -1.9 |
| North Myrtle Beach Airport | 1.93 | 9.81 | -3.8 | Charleston Air Force Base | 4.35 | 10.45 | -3.6 |
| Savannah, GA Airport | 5.20 | 12.19 | -1.9 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Columbia: 68 degrees. Barnwell: 63 degrees. Mullins: 67 degrees.
Widespread heavy rainfall was observed during the period, with most of the state recording at least an inch and a half of rain, and with over five inches of rain reported in portions of Aiken, Allendale, Barnwell, Hampton, and Orangeburg counties. A CoCoRaHS observer in Allendale County recorded 9.01 inches. The rainfall during the period helped reduce the year-to-date precipitation deficits at many locations. The U.S. Drought Monitor map, released on Thursday, May 13, showed a one-category improvement due to the widespread rainfall. However, portions of Charleston, Georgetown, and Horry counties remained in severe drought (D2) due to the long duration of dry conditions before the rain as well as persistent low streamflow values.
With over two inches of rain falling across most of the state's river basins, the 14-day average streamflow values rose to normal levels, with many rivers showing significant flow improvements over the past two weeks. However, gauges in parts of the Pee Dee Basin continued to record below-normal values, including the Black River at Kingstree, the Lynches River at Effingham, the Little Pee Dee River at Galivants Ferry, and the Waccamaw River at Longs. The height levels at some river gauges have reached action and minor flood stages, while tidal gauges remained below flood stage.
