WEEKLY SOUTH CAROLINA WEATHER 2018
November 19, 2018 - November 25, 2018
As the coastal trough pulled away from the South Carolina coast on the morning of Monday, November 19, the CoCoRaHS stations in the coastal counties reported up to 0.40 inches of rain. Many portions of the state started the morning with dense, patchy fog, and the National Weather Service (NWS) automated stations at the Rock Hill-York County Airport and Myrtle Beach Grand Strand reported visibilities less than half a mile. Other stations across the state also measured reduced visibilities, including only 2 miles at the Greenwood Airport and 4 miles at the Charleston International Airport. Some stations in the Upstate started with temperatures near freezing, like the National Weather Service (NWS) Cooperative Weather station in Walhalla which reported a low of 33 degrees. Temperatures in the Lowcountry started the morning in the upper 40's and climbed to the low to mid 70's.
Another morning of patchy, dense fog on Tuesday, November 20 along the many coastal and Lowcountry counties. Minimum temperatures were slightly above normal for many locations in the Midlands, including the NWS stations at Saluda and Little Mountain which reported a low of 50 and 51 degrees, respectively. The cold front that moved through the state on Tuesday had limited moisture and produced spotty shower activity, and most of the reporting stations had less than a tenth of an inch of rainfall. After the front passed through the area, it was a very quiet weather-related pattern. A weak high pressure centered over the Mississippi River Valley built in behind the front on Wednesday and would dominate the weather through Thanksgiving, providing drier and cooler conditions. Clear skies helped with radiational cooling and patchy frost in the Upstate and Midlands, and many locations observed minimum temperatures in the upper 20's to mid 30's, while high temperatures during the day ranged from the mid-50's to mid-60's across the state.
The low temperatures on Thanksgiving morning were up to 10 degrees below normal, including locations near the coast, such as McClellanville which reported a minimum temperature of 40 degrees. With the cool, dry air, high temperatures struggled to get out of the 50's for many locations, and the NWS stations at the Florence and Orangeburg Regional Airports recorded maximum temperatures of 59 degrees. Rainfall was fairly minimal over many areas of the Lowcountry and the Thursday, November 22 release of the National Drought Monitor, continued to hold the dry (D0) to moderate (D1) drought conditions along the coast of Beaufort, Charleston, and Jasper counties and inland to include Allendale, Berkley, Colleton, Dorchester and Hampton counties. Thursday morning also marked the start of the second round of King Tides for the month and the Charleston Harbor tidal gauge observed an astronomical high tide value of 7.06 ft. mean lower low water (MLLW) around 7:00 a.m. and caused minor saltwater flooding in low-lying areas.
On Friday, November 23, the high pressure moved off the East coast as a cold front, and the low-pressure system started to move in from the west, increasing the onshore and northeast flow and bringing moisture back into the region. Temperatures, The combination of the atmospheric pattern and King Tides, caused major coastal flooding along the entire South Carolina coast on both Friday and Saturday. The Downtown Charleston Harbor Gauge recorded a MLLW of 8.14 ft in the morning and 7.23 ft in the evening; Oyster Inlet reported MLLW of 7.5 ft. and the Springmaid Pier recorded 7.93 ft the same morning. The flooding on Edisto Island may have been from both wash up from the beach and from the marsh near the Wadmalaw River. In Downtown Charleston, numerous roads were closed and impacted due to the saltwater flooding, and a County Emergency Management Official reported that the berm located near the intersection of Morrison Drive and Jackson Street was breached. The White Point Garden area was flooded with the water reaching within six inches of breaching the seawall of The Battery. Additional reports of coastal flooding were made in Folly Beach, Mount Pleasant with extensive flooding along Shem Creek, on Sullivans Island, and along the Ashely River.
The air mass center over New England extended southwest across the Carolinas, combined with the low-pressure system off the coast to create another cold air damming scenario for the state. Widespread precipitation over the region late Friday night and into Saturday morning produced a wintry mix in portions of the Upstate. Freezing rain coated trees in ice on Paris Mountain and reports of a little icing on trees and power lines was made from the Gaffney area. Under the wedge of cold air, temperatures in the Midlands held in the upper 40's to mid 50's, while along the coast temperatures were in the upper 60's to near 70 degrees in Charleston. For the second day in a row, the wind and King Tides caused major coastal flooding. The tidal gauge at Charleston Harbor reported a MLLW of 8.72 ft., the 6th highest tide recorded in Charleston since 1901, and it surpassed the historic flooding during the October 2015 event. The MLLW at the gauges at Oyster Landing and Springmaid Pier were both over 8 feet, with readings of 8.3 ft. and 8.71 ft., respectively. Many media and social media outlets posted pictures of the saltwater flooding as it impacted coastal areas from Daufuskie Island to Myrtle Beach.
Once again, coastal flooding from the King tides was an issue during the morning of Sunday, November 25 am. The tidal gauges along the South Carolina coast recorded a high tide MLLW levels nearly a foot higher than predicted, including 7.69 ft. reported from the Charleston Harbor Gauge. Reports of coastal flooding were made from many locations along the coast, but not as extensive as the previous two days. Dense fog was observed across much of the state, with visibilities reduced to less than a quarter of a mile in some locations. The fog did not dissipate in some areas until late Sunday morning, causing delays and traffic issues during the holiday weekend. The temperatures on Sunday were a repeat of Saturday across the state as another cold front began to approach the area, bringing some rain and colder temperatures for the start of the work week.
(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.)
The highest temperature reported was 75 degrees on November 19 at the Savannah NWR RAWS station located in Jasper County.
The lowest temperature reported was 27 degrees at Chesnee in Spartanburg County on November 20.
The maximum 24-hour precipitation reported was 2.28 inches at the National Weather Service Station located at the North Myrtle Beach Grand Strand Airport ending at midnight on November 24.
The CoCoRaHS Station Myrtle Beach 2.4 ENE (SC-HR-64) reported a 24-hour precipitation total 1.63 inches, ending at 8:00 a.m. on November 25.
The state average precipitation for the seven-day period was 0.7 inches.
| ||Weekly*||Since Jan 1||Departure
|Charlotte, NC Airport||0.63||52.03||14.3
|Columbia Metro Airport||0.33||42.26||1.4
|Augusta, GA Airport||0.17||48.89||9.2
|North Myrtle Beach Airport||2.48||61.08||13.0
|Charleston Air Force Base||0.94||47.94||0.4
|Savannah, GA Airport||0.20||34.83||-9.8
| *Weekly precipitation totals ending midnight Sunday.
4-inch depth soil temperature: Clinton: 49 degrees. Columbia: 56 degrees. Barnwell: 51 degrees. Mullins: 53 degrees.
Rainfall totals over the 7-day period were normal to slightly below normal across the state, with portions of the Central Savannah River Area (CSRA) receiving less than 0.50 inches of rain. The light to moderate intensity of the rainfall did not cause any significant flash flooding issues. However, some of the rivers that reported an increase in streamflow values and stage heights last week, remained high through Sunday. Some rivers, including the Congaree, Little Pee Dee, Pee Dee, and Wateree fell from moderate flood stage but still recorded minor flooding stage heights. Rivers and across most of the Palmetto state continued to report streamflow values that were much above normal for this time of year, with about half a dozen gauges reporting normal streamflow, especially around the CSRA.
COASTAL OCEAN TEMPERATURES:
Charleston Harbor (CHTS1): 60.3 degrees.
Capers Nearshore Buoy (Station 41029): 60.8 degrees.
Fripps Nearshore Buoy (Station 41033): Not Available.