Warm and moist conditions between a trough of low pressure inland and high pressure over the Atlantic led to a few strong/severe thunderstorms ahead of a sea breeze circulation across Southeast Georgia.
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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.
Warm and moist conditions between a trough of low pressure inland and high pressure over the Atlantic led to a few strong/severe thunderstorms ahead of a sea breeze circulation across Southeast Georgia.
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 Aug 19, 2:33 PM EST, 1 hour 32 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 333 PM EDT Sun Aug 19 2018 .SYNOPSIS... The area will be situated between an inland trough and Atlantic high pressure through Tuesday. A cold front will approach the area from the northwest on Wednesday, then stall over or near the region through the end of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Expect scattered showers and storms to develop through early evening as the sea breeze meanders inland and combines with additional convection and associated boundaries farther inland. This convection will diminish overnight as the best instability and forcing shift offshore. Given DCAPEs near 1000 J/kg near the coast, especially in GA, we cannot rule out a severe storm or two through early evening if convection can organize a bit. Also, fog may develop late, mainly inland where rain falls. Lows will generally range from the lower to mid 70s to the upper 70s/near 80 at the coast. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Monday: Short wave ridging will develop aloft in response to building heights from the parent anticyclone between Bermuda and the Bahamas, while a digging trough will cross the Great Plains and MS Valley during the day, eventually reaching the OH and TN valleys by 12Z Tuesday. At the surface, the pattern is basically the same as it has been of late, featuring a weak inland trough and the Bermuda-Azores High aligned just off to the SE and S. The environment remains fairly capped with more large scale subsidence and the warm mid levels, and it'll take until around 2-3 pm to reach our convective temps that are near 90F. With less overall moisture than recent days, as PWat ranges from near 1.6" S to 2.0" N, the risk for showers/t-storms is nothing higher than 20-30% chances during the mid afternoon into the evening. Any pulse severe risk is non-zero, since DCAPE is still forecast as great as 1000 J/kg. Some late night marine convection from offshore could brush Charleston County, but with the steering flow WSW, we have kept any mentionable PoP over the Atlantic. Status quo on max and min temps; with both slightly warmer than normal. Tuesday: The upstream short wave trough will pass through the OH and TN valleys during the daytime hours, dampening somewhat as it heads toward the mid-Atlantic and NE at night. As this transpires a cold front will push SE and approach the forecast district late at night, as the oceanic ridge is nudged further to the SE. The prospects for diurnal convection is near or actually a little below normal, as moisture profiles are even less than on Monday, as PWat is down ~1.5- 1.8". Thus we have nothing higher than 20-30% POP in the afternoon when convective temps are achieved. DCAPE is again near 1000 J/kg, so the severe risk is non-zero. The tail of the short wave and its accompanying RRQ of the upper jet will move into the area during the late evening and overnight, and this should keep at least isolated to scattered PoP in the forecast even during the typical nocturnal minimum period. Little change in both max and min temps from recent days, although if coverage of convection is more than now forecast Tuesday night, overnight lows would be a few degrees lower than now forecast. Wednesday: The short wave from at night will cross into the Atlantic during the morning, followed by DNVA into the afternoon. However, a secondary short wave will drop through the western Great lakes and help to maintain a broad mid and upper trough across a good part of the eastern states. This forces a cold front to push into or near the forecast zones, and that will be the main mechanism for the development of showers and t-storms. The latest guidance shows the main axis of moisture just off the coast, and due to this we are hesitant to go anything more than scattered PoP, which "meshes" well with surrounding WFO's. The forecast could require adjustments though, pending where the cold front positions itself, and where the best moisture plume sets up. Temps mainly 90-93F inland from the coast. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Models show a long wave trough over the eastern half of the country Wednesday night. This trough will gradually shift eastward and then lift to the north into Friday, followed by zonal flow on Saturday. At the surface, a front is forecasted to stall over or just offshore of our area during this time period. This will lead to above normal POPs and near or maybe even below normal temperatures. But if the front positions itself further offshore, then large changes in the forecast would be needed. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... 18Z TAFs: Generally VFR conditions expected. There is a small risk of MVFR cigs at KCHS/KSAV this afternoon. Otherwise, the best chance of impacts from showers and thunderstorms looks to be late this afternoon into early evening. Extended Aviation Outlook: Small probabilities of brief flight restrictions Monday and Tuesday due to afternoon/evening convection. Higher probabilities of brief flight restrictions due to convection associated with a front Wednesday through Friday. && .MARINE... Tonight: Typical late-summer pattern with S/SW winds this evening shifting to SW overnight. Speeds will average 15 kt with some higher gusts with seas 2-4 ft. Some stronger storms are possible across the waters, mainly through this evening. Monday and Monday night: A modest SW'erly gradient will exist between an inland trough and the Atlantic High to the SE and S. With a boost from the sea breeze influences and subtle nocturnal low level jetting, winds will be as high as 15 kt and gusty. With little swell energy, seas will be generally be no larger than 2 or 3 ft. Tuesday through Wednesday: The offshore ridge is forced a little further SE as a cold front eventually slips closer to the SE coast during mid week. The gradient tightens between these two large scale features, especially late Tuesday and into Tuesday night, where S-SW winds will reach as high as 15-20 kt with higher gusts. Seas will respond and build to as high as 3-4 ft, maybe even 5 ft across the northern AMZ350 waters. Thursday through Friday: The cold front will become stationary over or near the waters the second part of the week, as continental high pressure builds to the NW and N. Depending upon where the front stalls out and the exact strength to the land based high, there could be adjustments to the latest wind and sea forecasts. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && NEAR TERM...RJB SHORT TERM...33 LONG TERM... AVIATION...33/RJB MARINE...33/RJB
Hazardous Weather Outlook National Weather Service Charleston SC 306 AM EDT Sun Aug 19 2018 AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040- 042>045-047>052-200715- 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-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- 306 AM EDT Sun Aug 19 2018 This Hazardous Weather Outlook is for Atlantic coastal waters, southeast Georgia and southeast South Carolina. .DAY ONE...Today and 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 Charleston,SC radar (KCLX), 40 km away, was scanning. The volume nearest the first event began at 21:06 UTC.
1 lightning, 1 thunderstorm wind. Local standard time, as filed.
The Island Packet Newspaper reported a house in the Pleasant Point neighborhood was struck by lightning and burned to the ground.
A tree was reported down on Interstate 95 near mile marker 14.
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, August 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 2026-09-24. Each event’s entry at NCEI: 781115, 781116.