The high pressure dominated the weather pattern at the beginning of the work week, with the threat of another storm system to affect the state before the holiday travel weekend. On Monday, December 17, morning low temperatures were slightly above normal, and many stations reported minimum temperatures above freezing. Under sunny skies, much of the state observed temperatures reaching the mid to upper 60’s, including the National Weather Service (NWS) station at the Greenville Spartanburg Airport which reported a high temperature of 67 degrees, more than 10 degrees above normal for this time of year. The dry conditions persisted into Tuesday, December 18, under the influence of the high pressure. Patchy fog developed in the Lowcountry, with visibilities reduced to less than two miles near some of the inland coastal communities. Maximum temperatures were slightly cooler than the previous day, but still above normal, with temperatures in the upper 50’s to mid 60’s across the state. The high-pressure system began to shift to the east on Wednesday, December 19, and the tranquil weather started to give way as increased cloudiness and moisture moved into the Southeast. The relatively warm temperatures returned closer to normal and none of the CoCoRaHS and NWS stations measured more than a trace of precipitation.
Unsettled weather conditions started to move into the area during the early morning hours on Thursday, December 20, as an anomalously deep low pressure began to cross into the region. With the atmospheric set up, there was a marginal risk of severe thunderstorms, mainly from Interstate 95 toward the coast, and a threat of heavy rain. The NWS offices across the state issued Flood Watches for the already soggy state. CoCoRaHS stations in Greenville County measured up to three inches of rain from the storm system, while rainfall totals near the coast were closer to half an inch. As the storm system moved through the area, wind advisories were issued for most of the state, as breezy to windy conditions were expected to develop. The strong low-pressure system moved to the northeast, away from the state, but provided enough moisture for light showers to form during the late morning and into the evening hours. The wind was the main weather story on Friday, December 21. The NWS station at the Charleston International Airport reported a maximum wind gust of 45 mph, with sustained winds near 30 mph. The Mount Pleasant Police Department reported that a shipping container unit on a truck was blown over on the eastbound side of the James B Edwards Bridge on Interstate 526. The container leaned against the concrete wall on the bridge and both eastbound lanes were closed to traffic. Further up the coast, the Myrtle Beach Grand Strand Airport observed a maximum wind gust of 37 mph. The U.S. Coast Guard reported a tree down at the Socastee swing bridge, causing navigation issues with marine traffic on the Intracoastal Waterway. Other stations across the Midlands and Pee Dee reported wind gusts over 35 mph, including the Columbia Metropolitan Airport and the Florence Regional Airport.
Behind the storm system, high pressure built back into the area on Saturday, December 22, but mostly cloudy conditions prevailed over the area, keeping low temperatures across the most of state above freezing. Under the cloudy skies, high temperatures reached the mid 50’s, and the NWS station at the Clemson/Oconee County Airport reported a maximum temperature of 52 degrees. By Saturday, the remaining snow at the NWS station at Caesars Head from the December 9 snow storm had melted and the snow depth was reported as only a trace. A weak cold front, with little moisture, passed through the region on Sunday, December 23. Stations in the Upstate recorded light rainfall amounts as isolated showers developed and cleared out of the region.
(Note: The highest and lowest official temperatures and highest precipitation totals provided below are based on observations from the National Weather Service Cooperative Observer network and the National Weather Service's Forecast Offices.)| Weekly* | Since Jan 1 | Departure | |
|---|---|---|---|
| Anderson Airport | 1.59 | 57.54 | 14.3 |
| Greer Airport | 2.94 | 66.27 | 20.1 |
| Charlotte, NC Airport | 1.78 | 57.95 | 17.2 |
| Columbia Metro Airport | 0.64 | 47.84 | 4.1 |
| Orangeburg Airport | 0.54 | 44.34 | -1.7 |
| Augusta, GA Airport | 1.71 | 54.07 | 11.4 |
| Florence Airport | 1.21 | 57.12 | 15.0 |
| North Myrtle Beach Airport | 0.57 | 67.58 | 16.3 |
| Charleston Air Force Base | 1.29 | 57.15 | 7.0 |
| Savannah, GA Airport | 0.15 | 42.02 | -5.1 |
| *Weekly precipitation totals ending midnight Sunday. |
4-inch depth soil temperature: Clinton: 44 degrees. Columbia: 52 degrees. Barnwell: 45 degrees. Mullins: 46 degrees.
Much of the state received at least one inch of rain over the seven day-period, with isolated locations in the Upstate reporting five inches, and widespread reports of up to six inches in Charleston, Dorchester and Georgetown counties. With only seven days left in 2018, the Central Savannah River Area (CSRA) remains the drier part of the state, with annual rainfall totals measuring close to ten inches below normal. The heavy rainfall on Thursday and Friday caused some minor flooding issues in the Lowcountry and Upstate. The rainfall from this storm system caused rivers to rise in watersheds across the state, with some moderate flooding along portions of the major river systems, including the Congaree, Wateree, Savannah, Pee Dee, Little Pee Dee and Santee rivers. These rivers were running near full bank. Many rivers, creeks and streams across the Palmetto State continued to report streamflow values that were still much above normal for this time of year.
Charleston Harbor (CHTS1): 55.9 degrees.
Capers Nearshore Buoy (Station 41029): 56.7 degrees.
Fripps Nearshore Buoy (Station 41033): Not Available.
