Dry and cool air was in place for the beginning of the week, as high pressure settled across the eastern US on Monday, December 11, providing tranquil weather and sunny skies through Friday. The cold front had pushed through the entire state, and temperatures were five to ten degrees cooler than normal on Monday and Tuesday, with highs in the 50s and lows in the upper 20s to mid-30s.
Temperatures on Wednesday morning were the coldest during the period, with many locations dropping below freezing before warming into the low to mid-60s for highs. A weak, reinforcing boundary moved through the region Wednesday evening, providing cooler and drier air. Mostly clear skies and cool temperatures continued during the mornings, while temperatures were near normal for daytime highs on Thursday and Friday.
On Saturday, December 16, a low-pressure system developed in the Gulf of Mexico and moved across the Florida Peninsula. As the system approached and strengthened, rain spread into the region overnight. The brunt of the impacts of the storm occurred on Sunday, with heavy rain, gusty winds, and moderate to major coastal flooding. The preliminary tide data shows a crest of 9.97 ft MLLW at Springmaid Pier on Sunday afternoon, which would be the fourth-highest tide at the location, and a crest of 9.86 ft MLLW at the Charleston Harbor Tidal Gauge, which would be the fourth-highest crest on record at the location. The Wilmington National Weather Service Office conducted a storm survey and confirmed tornado damage near Myrtle Beach. Wind gusts up to 45 mph were reported across the Coastal Plain, with higher gusts directly along the coast. The 67-mph wind gust reported at the Florence Regional Airport was likely produced by a suspected gravity wave behind the exiting convection storm. Rainfall total reports ranged between ten and fifteen inches of rainfall in parts of Charleston and Georgetown counties from the band of heaviest rain, which trained over the area as the storm moved along the coast. There were widespread reports of flooded and washed-out roads in Charleston, Georgetown, and Horry counties.
(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 | 0.14 | 43.96 | -0.4 |
| Greer Airport | 0.26 | 49.14 | 1.6 |
| Charlotte, NC Airport | 1.51 | 43.72 | 1.8 |
| Columbia Metro Airport | 2.23 | 54.01 | 10.6 |
| Orangeburg 2 (COOP) | 2.24 | 57.11 | 8.5 |
| Augusta, GA Airport | 2.81 | 62.18 | 20.0 |
| Florence Airport | 2.65 | 45.97 | 2.4 |
| North Myrtle Beach Airport | 3.79 | 43.23 | -3.9 | Charleston Air Force Base | 3.34 | 51.17 | 0.2 |
| Savannah, GA Airport | 3.46 | 41.18 | -5.5 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: 48 degrees. Columbia: 55 degrees. Barnwell: 48 degrees. Mullins: 50 degrees.
Conditions were mainly dry through the work week, with an intense winter storm providing rain across the state from late Saturday through Sunday. The highest rainfall totals were reported in Charleston, Georgetown, and Horry counties, which experienced widespread observations of six to twelve inches of rain. One CoCoRaHS observer near McClellanville and one south of Georgetown measured two-day totals of over fourteen inches of rain. Areas of the Midlands and Pee Dee recorded over two inches of rain, and locations in Beaufort and Jasper counties received up to five inches of rain. Unfortunately, the Upstate received less than an inch of rain from the system. The rainfall came after the December 14 release of the US Drought Monitor (USDM) map, which showed the removal of extreme (D3) drought conditions across parts of the Upstate due to rains in the previous period and some improvements to the severe (D2) and moderate drought (D1) conditions in portions of the Midlands and Pee Dee regions.
The rain during the previous period and most of this period led to slight improvements in streamflow values across much of the state. The 14-day average streamflow values in portions of the Broad, Catawba, Pee Dee, Lynches, and Saluda river basins that had dropped to much below normal reported some increased flows. Only a handful of stations were still reporting stream flows that were much below normal. While the river height gauges across the state reported levels below flood stage, tidal gauges reached the moderate and major flood stage on Sunday morning due to the intense winter storm that moved along the coast.
