The main weather stories during the period were the abnormally cooler-than-normal temperatures and a weak low-pressure system that caused rain over the holiday weekend.
On Monday, May 22, light rain fell over a portion of the state as a cold front cleared the region, stalling near the coast, and an area of low pressure developed over the Florida Panhandle. While overnight temperatures were near normal in the 60s, daytime temperatures rose into the upper 70s, up to ten degrees below normal. Conditions on Tuesday were like those observed on Monday, with scattered showers and below-normal temperatures. However, persistent northeasterly winds pushed some smoke from wildfires in Canada into the region, causing hazy skies. By Wednesday, the lingering cold front shifted further offshore, leading to drier conditions and calmer weather across the state. Morning temperatures on Wednesday dropped into the lower 50s in parts of the Upstate, and highs reached the low to mid-80s. Another cool morning occurred on Thursday, with low temperatures up to fifteen degrees below normal. Some Upstate and northern Midlands stations observed minimum temperatures in the upper 40s to low 50s. A few showers developed along the Coastal Plain; otherwise, the cool and dry conditions prevailed.
Rain chances and northeasterly winds increased throughout the day on Friday as a coastal low-pressure system developed off the Southeast coast. While offshore buoys recorded wind gusts up to 60 mph, coastal and inland stations reported gusts as high as 45 mph. The rain started late on Friday, and there were reports of between two and three inches of rain in Beaufort, Charleston, and Hampton counties by Saturday morning. In addition to the rain, multiple daily record low-high temperatures were broken or tied as temperatures felt more like the end of February than the end of May. The National Weather Service (NWS) station at the Columbia Metropolitan Airport recorded a high of 64 degrees, breaking the record of 68 degrees set in 1972, and the NWS Charleston International Airport station tied the record of 66 degrees set in 1972. The coastal low-pressure system had some tropical characteristics before it moved onshore and slowed down on Sunday, creating another day of dreary conditions with cloudy skies, below-normal temperatures, and rain.
(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 | 0.88 | 24.40 | 5.2 |
| Greer Airport | 0.97 | 29.64 | 9.5 |
| Charlotte, NC Airport | 2.17 | 20.40 | 3.0 |
| Columbia Metro Airport | 1.77 | 24.10 | 7.8 |
| Orangeburg 2 (COOP) | 1.33M | 21.00M | 2.5M |
| Augusta, GA Airport | 1.61 | 26.11 | 9.0 |
| Florence Airport | 1.40 | 18.10 | 2.6 |
| North Myrtle Beach Airport | 1.64 | 15.05 | -0.2 | Charleston Air Force Base | 2.11 | 15.10 | -0.8 |
| Savannah, GA Airport | 1.38 | 17.83 | 1.7 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: 66 degrees. Columbia: 67 degrees. Barnwell: 60 degrees. Mullins: 63 degrees.
Most of the state recorded at least half an inch of rainfall during the period, with widespread rainfall totals of one to two inches across much of the Coastal Plain, and a few CoCoRaHS observers near Gaffney and Rock Hill recorded close to two inches of rain during the period. In Charleston and Georgetown counties, some observers measured over two inches of rain from the weak low-pressure system that impacted the state over the holiday weekend. There was a decrease in the percentage of area in the Lowcountry and Pee Dee affected by abnormally dry (D0) conditions in the Thursday, May 23, release of the United States Drought Monitor map.
The 14-day averages for most stream flow values in the state’s watersheds remained at average flow values. However, areas that received higher rainfall amounts during the period saw streamflow increases in some of the smaller tributaries, especially in the Central Savannah River Area and southern Midlands. Even with rain in the Pee Dee, additional gauges reported drops in stream flow values, with much below expected flows at the gauge on the Lynches River near Effingham. The rain caused some river heights to increase, with a few river height gauges in the Edisto and Savannah River basins reaching the action stage. Elsewhere across the state, river heights remained below the action stage.
