A mid-level shortwave rounded the southern edge of low pressure centered over the Carolinas and encountered a highly unstable environment across Southeast Georgia, leading to strong/severe thunderstorms during afternoon hours.
Every event with a place to put it. Tap one for its entry below.
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.
A mid-level shortwave rounded the southern edge of low pressure centered over the Carolinas and encountered a highly unstable environment across Southeast Georgia, leading to strong/severe thunderstorms during afternoon hours.
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 13, 9:53 AM EST, 3 hours 11 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 1053 AM EDT Mon Aug 13 2018 .SYNOPSIS... Low pressure will persist over inland areas today before a weak front drifts into the area and dissipates during the middle of the week. High pressure will prevail during the second half of the week before low pressure returns during the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1040 AM: Coastal thunderstorms have started to weaken off the Charleston County coast. These storms are expected to continue to dissipate headed into the mid-day hours. The mid- level water vapor indicates the position of the trough axis, pushing toward the coast. CAMs indicate that thunderstorms will develop along and ahead of this feature this afternoon, especially across the CHS Tri-county area. I will update the forecast to increase PoPs, QPF, and weather during the afternoon. There is some potential for training cells to occur over the Highway 17 corridor, over Downtown Charleston, possibly resulting in excessive rainfall rates. Previous Discussion: Today: The southern flanks of a substantial mid level cut-off low pressure area will reside over the Carolinas today. A decent short wave will rotate through the base of the low, impacting areas to our north from Eastern NC to the Mid Atlc. The forecast for the local area today is a bit on the tricky side with a drier deep layered air shifting into our western zones today while increasing upper difluence is noted along coastal SC zones during the afternoon hours while sea breeze moisture convergence becomes maximized. We maintained a good persistence forecast with highs in the mid 90s well inland to the lower 90s coast today. Convection: The flair of the models for several runs now continues to show similar solutions with much of the uncertainties riding on the mesoscale subtleties and the arrival of drier air upstream. Convective initiation looks to develop earliest across Southeast SC then later in the day in GA. We have opted to maintain general POP scheme persistence as chance POPs still in line with overall model trends similar to previous thinking. The main issue revolves around tstm intensity today as quite a bit of coastal instability is progged ahead of a well defined region of much higher DCAPES advecting east with the drier upper levels later today. The latest CAM output shows much of the coverage at 18Z-22Z today should be confined right to the sea breeze along the coastal zones. Some of these storms could be locally strong/severe if the atmosphere remains uncontaminated from any earlier convection up to that point. Late day or evening tstms in the eastern half of Southeast GA may also be strong with a localized damaging wind risk but confidence is not good timing uncertainties between models is rather substantial and mesoscale boundaries the big players. Tonight: Convection could linger along coastal GA with mainly dry weather elsewhere. Lows will be a bit cooler with some near 70 degree readings far inland to the mid 70s coast. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Conditions will trend drier into mid-week as a mid/upper lvl low centered north of the region slowly shifts off the Mid-Atlantic and Northeast coast Tuesday into early Wednesday before a ridge of high pressure expands over the region from the Atlantic by Thursday. However, chances of showers and thunderstorms are still possible on Tuesday, especially closer to the coast as a weak sfc front attempts to shift into the area before stalling and/or dissipating through Wednesday. A prevailing west/northwest flow aloft should also help keep most locations drier well inland and warm sfc temps into the lower 90s Tuesday, then limit most convection and support slightly warmer temps into the low/mid 90s on Wednesday. By Thursday, a more typical summertime pattern will be in place with the Atlantic ridge expanding aloft and the area remaining between weak low pressure inland and Atlantic high pressure at the sfc. The pattern should support another day of warm temps on Thursday with highs peaking in the low/mid 90s and a slight chance to chance of showers and thunderstorms, mainly during the afternoon/evening. Overnight lows should range in the low/mid 70s through mid week. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A typical summertime pattern should persist into early Friday as high pressure prevails aloft and a sfc trough of low pressure remains less pronounced inland. However, greater chances of precip should return this weekend as a mid/upper lvl trough of low pressure quickly advances over the Midwest and Northeast states and forces the Atlantic high to weaken and retreat offshore. Greatest chances of precip should occur inland and north late weekend into early next week, closer to a trough axis west of the area and a front approaching the Mid-Atlantic states to the north. Once the mid/upper lvl trough of low pressure shifts offshore late Monday, the Atlantic ridge of high pressure should return aloft. Overall high temps should peak into the lower 90s, with temps perhaps a degree or two cooler late weekend into early next week should greater precip coverage occur. Lows should range in the mid/upper 70s, warmest near the coast. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... The main problem today will revolve around potential convection in the vicinity of the terminals and especially the timing at both major airports. We maintained VCTS at KCHS from just after midday to late afternoon and at also at KSAV, however the timing there was just a bit later per latest trends. Brief flight restrictions will occur around tstms with lower vsbys in downpours. We suspect some lower clouds will develop tonight, however the best chances will occur well inland and we continue to indicate VFR conditions. Extended Aviation Outlook: VFR conditions should prevail at CHS and SAV terminals Tuesday through Thursday. Brief flight restrictions are possible with afternoon/evening showers and thunderstorms this weekend. && .MARINE... Today through Saturday: Conditions are expected to remain below Small Craft Advisory levels through late week. However, a somewhat tightened pressure gradient between low pressure inland and high pressure offshore will support southwest/south winds up to 15-20 kt at times through at least Tuesday. Strong thunderstorms are possible later today into tonight with a risk for localized strong wind gusts near shore, very heavy rainfall and deadly lightning strikes. High pressure building over the coastal waters should lead to a more relaxed gradient and south/southwest winds topping out near 15 kt Wednesday and Thursday, before the gradient tightens once again this weekend and results in wind speeds up to 15-20 kt between low pressure inland and high pressure over the western Atlantic. Seas will generally range between 2-4 ft into Tuesday, then slowly subside to 1-3 ft Wednesday into Thursday, before building back to 2-4 ft by this weekend. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && NEAR TERM...NED SHORT TERM...DPB LONG TERM...DPB AVIATION... MARINE...
Hazardous Weather Outlook National Weather Service Charleston SC 433 AM EDT Mon Aug 13 2018 AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040- 042>045-047>052-140845- 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- 433 AM EDT Mon Aug 13 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...Tuesday through Sunday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
903 AM EDT MON AUG 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 AM WATERSPOUT 4 ENE SULLIVANS ISLAND 32.79N 79.77W
08/13/2018 AMZ350 SC FIRE DEPT/RESCUE
ISLE OF PALMS FIRE DEPARTMENT REPORTED A WATERSPOUT
SOUTH OF ISLE OF PALMS.
&&
EVENT NUMBER CHS1800743
SPRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
906 AM EDT MON AUG 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0854 AM WATERSPOUT 4 ENE SULLIVANS ISLAND 32.78N 79.78W
08/13/2018 AMZ350 SC FIRE DEPT/RESCUE
ISLE OF PALMS FIRE DEPARTMENT REPORTED A SECOND
WATERSPOUT SOUTH OF 18TH AVENUE ON ISLE OF PALMS.
&&
EVENT NUMBER CHS1800744
SPRSpecial Weather Statement
National Weather Service Charleston SC
943 AM EDT MON AUG 13 2018
SCZ050-131415-
Charleston-
943 AM EDT MON AUG 13 2018
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON COUNTY...
At 942 AM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Fort Sumter, moving northeast at 15 mph.
HAZARD...excessive cloud to ground lightning.
IMPACT...All outdoor activities should cease. Move indoors
immediately.
Some locations in the path of this storm include...
Mount Pleasant, Isle Of Palms, Sullivan's Island, Price Inlet, Bull
Island, Capers Inlet and Sullivans Island.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Beaches are especially dangerous during thunderstorms because
lightning will usually strike the tallest object in the vicinity.
Move off beaches and get in a sturdy structure or automobile
immediately. Many people have been killed by lightning on beaches in
the southeastern United States.
Report damage directly to the Charleston National Weather Service at
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.
&&
LAT...LON 3281 7969 3274 7985 3278 7989 3296 7960
3292 7954
TIME...MOT...LOC 1342Z 238DEG 12KT 3271 7982
NEDSpecial Weather Statement
National Weather Service Charleston SC
153 PM EDT MON AUG 13 2018
GAZ116>119-138-131830-
Inland Liberty-Coastal Chatham-Inland Chatham-Inland Bryan-Coastal
Bryan-
153 PM EDT MON AUG 13 2018
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BRYAN...LIBERTY AND
CHATHAM COUNTIES...
At 153 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Richmond Hill, moving northeast at 20 mph.
HAZARD...strong winds 45 to 55 mph, up to penny sized hail and
excessive cloud to ground lightning.
IMPACT...Expect minor damage to tree limbs and blowing around of
light, unsecured objects. Minor hail damage to plants,
trees and crops is possible. Damage to windshields is
unlikely. All outdoor activities should cease. Move
indoors immediately.
Some locations in the path of this storm include...
Savannah, Pooler, Richmond Hill, Wilmington Island, Montgomery,
Garden City, Thunderbolt and Vernonburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm and may lead to
flooding of low lying and poor drainage areas. Do not drive your
vehicle through flooded roadways.
Report damage directly to the Charleston National Weather Service at
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.
&&
LAT...LON 3194 8149 3213 8114 3203 8095 3188 8122
3189 8122 3188 8123 3178 8140
TIME...MOT...LOC 1753Z 245DEG 16KT 3190 8137
NEDThe Charleston,SC radar (KCLX), 83 km away, was scanning. The volume nearest the first event began at 18:03 UTC.
4 thunderstorm wind. Local standard time, as filed.
The Bryan County 911 Call Center reported two trees down in Richmond Hill. One small tree fell on a car in the Richmond Hill Library parking lot. The second tree was uprooted in the White Oak Village subdivision.
The Liberty County 911 Call Center reported a tree down near the intersection of Highway 84 and Old Sunbury Road.
The Long County 911 Call Center reported power lines down on Sandy Run Road.
The Long County 911 Call Center reported a tree down near the intersection of Thompson Road and Griffin Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2018Every state in 2018This day in weather historyWarnings in Georgia, 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: 781099, 781100, 781101, 781102.