Numerous thunderstorms associated with a Mesoscale Convective Vortex (MCV) west of the area shifted into Southeast South Carolina, eventually encountering an environment with dry mid-level air and resulting in damaging wind gusts over the region.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CHS wrote it up.
Numerous thunderstorms associated with a Mesoscale Convective Vortex (MCV) west of the area shifted into Southeast South Carolina, eventually encountering an environment with dry mid-level air and resulting in damaging wind gusts over the region.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Charleston, SC wrote its last area forecast discussion before the first event at Jun 24, 7:27 PM EST, 1 hour 35 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 827 PM EDT Sun Jun 24 2018 .SYNOPSIS... High pressure will extend across the region through Monday. A cold front will drop south into the area Monday and linger near or just south of the area through mid-week. Low pressure could develop off the Southeast U.S. next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Early this evening: All is quiet right now with the sea breeze progressing inland and just a few vertically challenged cumulus across the forecast area. However, a glance at regional radar imagery indicates convection is developing upstream and is on track to approach the forecast area later tonight. This upstream convection appears to be initiated and driven by some sort of MCV and the prevailing deep layer flow puts it on track to head toward at least the southeast South Carolina portion of the forecast area. The environment ahead of this developing convection is certainly unstable with MLCAPE on the order of 2,000-3,000 J/kg, which would seem to support further downstream development. However, we are losing insolation after sunset but the atmosphere is relatively untapped based on minimal convection the past several days. Dry air in the mid and upper levels results in DCAPE values around 1,000 J/kg which would support at least some degree of a damaging wind threat. Hi-res models such as the HRRR the the approaching convection intensifying as it interacts with the sea breeze across the Midlands. The idea is then that the convection progresses further to the southeast and impacts mainly the Charleston Tri- County region and Colleton County. Adjusted all forecast parameters to favor such a solution. Current timing would bring thunderstorms into the area around 9-10pm, then to the Charleston County coast around midnight. The overall severe threat is hard to judge given that thunderstorms will be coming through in the late evening. But, since the atmosphere is relatively untapped and DCAPE values are high, there is a potential for damaging winds, especially if convection can get organized along a line and become cold pool driven. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Few changes were made to ensure consistency with overnight shift. A cold front will approach from the northwest Monday and then move south into the area Monday night before stalling nearby through the rest of the period. This will mean a more unsettled period with decent rain chances is expected Monday night into at least Tuesday. Some of the storms could be strong late Monday afternoon/evening, mainly across SC, given the high DCAPE values (1000+ J/kg) and steep low to mid-level lapse rates. Temperatures will remain above normal Monday ahead of the front with heat indices peaking into the Heat Advisory range 105-108 inland, 108-112 coast. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Minor changes were made per regional coordination with NHC/WPC on the potential for low pressure developing off the Southeast U.S. coast. The latest medium range model guidance suggests the stalled cold front will dissipate as an offshore high pressure/inland trough pattern likely sets up. Low pressure is expected to develop off the SC/NC coast by late week and drop southwest to somewhere near or offshore of the GA/FL coast over the weekend per track coordination with NHC/WPC. Depending on the eventual development and track of the low, increased rain chances and breezy conditions could develop. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... The main concern is the potential for thunderstorms to impact KCHS this evening. Thunderstorms are developing upstream of the area and are expected to move through late this evening from the northwest. Confidence is increasing based on recent hi-res model runs, and prevailing VCTS has been added starting at 03z. A TEMPO is then in effect from 03-05z with low end gusty winds and MVFR visibilities. It does not appear thunderstorms will be a concern at KSAV. For the rest of the period, VFR conditions are expected. Extended Aviation Outlook: Risk for tstm impacts possible Monday Night into Tuesday and again by late week into the weekend depending on track of low pressure offshore. && .MARINE... Tonight: An inland surface trough and high pressure in the Atlantic will drive the weather pattern. Winds will peak along the immediate coastline through early this evening. Though, locally higher gusts are possible along the SC coastline. By late evening the winds will ease a few kt, then a second surge in winds is possible further offshore, lasting until almost daybreak. Additionally, winds closer to the coast should veer more towards the west around daybreak as the land breeze develops. Seas will average 2-3 ft, except 3-4 ft across the Charleston waters during the peak winds. There is a slight chance strong thunderstorms may develop inland this evening and move offshore tonight, producing hazardous weather for mariners. Monday through Friday: Few changes were made through mid-week to ensure consistency with the overnight shift. Southerly winds will prevail ahead of a cold front Monday with enhanced sea breeze influences possible. Front will backdoor into the region Monday Night into Tuesday. There is potential for low pressure to develop off the Southeast U.S. coast by late week. Small Craft Advisory conditions are not expected. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && NEAR TERM...BSH SHORT TERM...ST LONG TERM...RJB AVIATION...BSH/ST MARINE...MS/ST
Hazardous Weather Outlook National Weather Service Charleston SC 753 PM EDT Sun Jun 24 2018 GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-260000- Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans- Inland Bryan-Coastal Bryan-Inland Chatham-Coastal Chatham-Long- Inland Liberty-Coastal Liberty-Inland McIntosh-Coastal McIntosh- Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley- Inland Jasper-Beaufort-Coastal Colleton-Charleston-Coastal Jasper- Tidal Berkeley- 753 PM EDT Sun Jun 24 2018 This Hazardous Weather Outlook is for southeast Georgia and southeast South Carolina. .DAY ONE...Tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Excessive Heat: The combination of temperatures in the mid to upper 90s and moderate to occasionally high humidity will likely cause heat index values to exceed 105 degrees Monday. A Heat Advisory may be needed. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. AMZ330-350-352-354-374-260000- Charleston Harbor- Waters from South Santee River to Edisto Beach SC out 20 NM- Waters from Edisto Beach SC to Savannah GA out 20 NM- Waters from Savannah GA to Altamaha Sound GA out 20 NM, including Grays Reef National Marine Sanctuary- Waters from Savannah GA to Altamaha Sound GA extending from 20 to 60 NM- 753 PM EDT Sun Jun 24 2018 This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...Tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Monday through Saturday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time.
The Columbia radar (KCAE), 119 km away, was scanning. The volume nearest the first event began at 02:00 UTC.
14 thunderstorm wind. Local standard time, as filed.
The Berkeley County 911 Call Center reported a tree down along Highway 45 near Pineville.
Law enforcement reported a tree down on Highway 17A near Church Street.
A trained spotter reported trees down on a property along the 1000 block of High Hope Drive.
The Allendale 911 Call Center reported a tree down near the intersection of Conferderate Highway and Jenny's Road.
The South Carolina Highway Patrol reported a tree down in the 5200 block of Augusta Highway.
The Hampton County 911 Call Center reported multiple trees down.
Law enforcement reported a tree down across Mill Pond Road.
The South Carolina Highway Patrol reported a tree down along the 2000 block of Deliverance Road.
Law enforcement reported a tree down on I-95 southbound near mile marker 42.
The South Carolina Highway Patrol reported a tree down at the intersection of Magellan Road and Stanley Avenue.
The South Carolina Highway Patrol reported a tree down on Cane Branch Road near the intersection with Pellum Road.
Law enforcement reported a tree down on Highway 3 east of Grays.
Law enforcement reported two trees down across Peniel Road, including one at the intersection with Hendersonville Highway.
The South Carolina Highway Patrol reported a tree down on Highway 601 near Pineland.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Carolina in 2018Every state in 2018This day in weather historyWarnings in South Carolina, June 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 770868, 770870, 770871, 770872, 770873, 770874, 770876, 770877, 770878, 770879, 770881, 770882, 770885, 770886.