WEEKLY SOUTH CAROLINA WEATHER 2018
August 6, 2018 - August 12, 2018
Atlantic high pressure built over the state at the beginning of the week, with the position of the high funneling moisture into the state. This moist flow, combined with the instability in the atmosphere, allowed for the development of thunderstorms during the afternoon hours across South Carolina.
On Monday, August 6, a line of strong storms, with heavy rain, frequent lightning and high winds, moved through the Upstate. Quarter-sized (1.00 inch) hail was reported in Simpsonville and power lines and trees were reported down in Salem. Before the rain, the National Weather Service (NWS) station at the Greenville Downtown Airport observed a high temperature of 95 degrees, and the NWS station at the Greenville-Spartanburg Airport recorded a high of 93 degrees. The normal high temperature for the day is 90 degrees. The steeple from Langley First Baptist Church in Burnettown was blown off the church during a thunderstorm that moved through Aiken County. The combination of rainfall and high values of relative humidity on the morning of August 7 led to areas of thick fog across the mountain valleys. Dewpoints remained in the 70's in the Midlands and Upstate through the afternoon hours, pushing the heat indices values to around 105 degrees. A severe storm in Oconee County produced penny-sized hail in Walhalla and caused downed trees and power outages in Seneca.
The typical late-summer hot and humid weather conditions continued through the midweek. A surface boundary along the Appalachians and an upper-level disturbance from Tennessee helped convection to develop during the late evening hours of Wednesday, August 8, in the Upstate. There were multiple reports of trees down across Gowensville in Greenville County and Roebuck in Spartanburg County. Half-dollar-sized (1.25 inches) hail near Barksdale in Laurens County and numerous reports of downed trees were made from the Gray Court and Mountville areas. The series of storms moved rapidly across the mid-state. In the Midlands, pea-sized (0.25 inch) hail was reported near both Cheraw and Camden, and trees were knocked down in Chester, Edgefield and Newberry counties. Lightning struck a house west of Pageland in Lancaster County, causing moderate damage to the structure.
A weak cold front approached the state from the northwest on Thursday, August 9, producing strong thunderstorms in portions of the Upstate. Trees were knocked onto area roads and power lines in Aiken and Laurens counties. A personal weather station in Travelers Rest reported 3.30 inches of rain and a storm spotter reported quarter-sized hail (1.00 inch) hail near Fountain Inn in Greenville County. A HAM radio operator observed nickel-sized (0.88 inches) hail to the southeast of Anderson. Along the coast, pulse thunderstorms developed and dissipated along the sea breeze, as a cluster of severe thunderstorms pushed east-southeast across the Lowcountry. The combination of recent, heavy rains and strong winds from the thunderstorms caused two healthy 40-foot trees to be uprooted in Millett in Allendale County. A county building sustained minor damage in Allendale from a lightning strike, a result of the same storms. A trained spotter reported a wind gust of 58 mph in Colleton County near Henderson, and the AWOS station at the Lowcountry Regional Airport measured a 46-mph wind gust. Numerous reports of downed trees were received across the county. An automated weather station in Folly Beach measured multiple wind gusts over 45 mph, with a maximum gust of 52 mph. The National Ocean Service tide gauge located in Charleston Harbor measured a 39-mph wind gust, and other personal weather stations in the Charleston area observed wind gusts of 42 mph and 47 mph.
An upper-level trough positioned over the eastern United States pushed a cold front across the state and increased the rain chances through the weekend. A broad and weak area of low pressure persisted through the weekend. Another hot and humid set up for the Lowcountry, Midlands and Pee Dee regions occurred on Friday, August 10, with high temperatures in the upper 90's and heat indices up to 105 degrees. Most of the shower activity in the state was confined to a small portion of the Upstate. The NWS station at Table Rock measured 2.05 inches of rainfall. The evening of August 10 the tidal gauge in the Charleston Harbor observed a high astronomical tide value of 7.25 ft mean lower low water - MLLW. Typically, shallow coastal flooding begins along the lower South Carolina coast when tide levels reach 7.0 MLLW in the harbor. On Saturday, August 11, a cold front pushed through the Upstate and stalled over the Midlands. The low morning temperature highs were in the 70's to near 80 degrees along the coast, with the station at Myrtle Beach reporting a minimum temperature of 78 degrees. Another high tide value of 7.07 ft MLLW occurred at the Charleston Harbor tidal gauge around 9:00 p.m. on August 11.
The stalled front led to overnight thunderstorms on Sunday, August 12, in the northern Midlands and Pee Dee regions. Lightning caused a fire at an apartment complex in Sumter, damaging some units. Numerous roads were flooded and impassable in the cities of Sumter and Mulberry, causing vehicles to be stranded. The automated rain gauge at Shaw Air Force Base near Sumter measured 2.35 inches of rain in 2.5 hours, with 1.13 inches falling in roughly a 30-minute period around 10:30 p.m.
(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 official temperature reported was 98 degrees at the University of South Carolina - Columbia Campus in Richland County and Carolina Sandhills - South Carolina RAWS station in Chesterfield County on August 8.
The lowest official temperature reported was 59 degrees at Jocassee in Oconee County August 7.
The maximum 24-hour precipitation reported was 2.90 inches at the National Weather Service Cooperative Weather Station in Walterboro in Colleton County, ending at 9:30 a.m. on August 10.
The state average precipitation for the seven-day period was 0.70 inches.
| ||Weekly*||Since Jan 1||Departure
|Charlotte, NC Airport||0.70||28.45||2.4
|Columbia Metro Airport||0.49||22.27||-6.6
|Augusta, GA Airport||1.78||30.73||2.4
|North Myrtle Beach Airport||0.38||37.03||6.6
|Charleston Air Force Base||0.72||37.03||6.0
|Savannah, GA Airport||0.14||24.88||-5.5
| *Weekly precipitation totals ending midnight Sunday. |
4-inch depth soil temperature: Clinton: 78 degrees. Columbia: 81 degrees. Barnwell: 77 degrees. Mullins: 72 degrees.
The lack of rain across portions of the northern Midlands and Pee Dee regions over the last seven days led to a dropoff in streamflow values in some of the area creeks and rivers, such as Black Creek near Hartsville and the Lynches River near Bishopville. The dry out along the coast was welcomed after the previous two weeks of continual rainfall, and many of the river levels in the Lowcountry were falling back to normal levels. The Upstate received most of the rainfall this past week, and rivers in the area, like the Saluda River near Greenville, had above normal streamflow going into August 13.
COASTAL OCEAN TEMPERATURES:
Charleston Harbor (CHTS1): 83.8 degrees.
Capers Nearshore Buoy (Station 41029): 81.1 degrees.
Fripps Nearshore Buoy (Station 41033): 84.0 degrees.