A sea breeze circulation within a moderately unstable atmosphere between a trough of low pressure inland and a ridge of high pressure offshore led to severe thunderstorms 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.
A sea breeze circulation within a moderately unstable atmosphere between a trough of low pressure inland and a ridge of high pressure offshore led to severe thunderstorms 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 11, 7:01 PM EST, 0 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 801 PM EDT Tue Aug 11 2020 .SYNOPSIS... The region will remain positioned between Atlantic high pressure well to the east and inland low pressure. A weak cold front could approach the area over the weekend and linger in the vicinity into early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Early this evening: Mostly scattered coverage of thunderstorms this evening, primarily impacting southeast Georgia. Most of the activity has been fairly weak, except for one storm that has pulsed up with 60+ dBZ over the -20 C height (nearly 27 kft) and over 100 knots of storm top divergence. This storm is currently warned for and will be impacting Fort Stewart and the Hinesville area. Otherwise, storms are progressing from north to south and should stay just in the scattered coverage range through the rest of the evening. Focus for convection will then shift to the coastal waters yet again and rain chances have been constructed to reflect this. Overall, no significant fog or stratus concerns. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... A broad, deep layer trough remains inland with a Atlantic high pressure to the east-southeast. South-southwest low-level flow is expected to become onshore near the coast each afternoon due to the sea breeze. The sea breeze and convective outflow boundaries will be the main focus for any showers and thunderstorms. Generally chance to low-end likely PoPs are forecast for the afternoon and early evening showers and thunderstorms each day with an isolated strong to severe thunderstorm possible. Upper level flow remains weak and will continue to result in slow-moving or virtually stationary storms. With plenty of deep layer moisture and PWATs near 2 inches, some storms could produce locally heavy rainfall. High temperatures remain in the normal range, mostly in the lower 90s with upper 80s on Friday. Overnight lows in the lower to mid 70s, except upper 70s along the immediate coast. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Models continue to lack consistency in the long term period. Broad troughing aloft appears to shift towards the East Coast over the weekend into early next week. At the surface, a weak front could approach the region and then linger over or near the area. This setup will generally favor higher than normal rain chances, although given a good amount of disagreement between models, refinements will be needed. Temperatures will be near climo. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... VFR conditions should prevail at KCHS and KSAV through 00z Thursday. Through the rest of the evening, thunderstorms should stay just west of KSAV, though it is possible for one to pass within the vicinity. No concerns at KCHS. We expect additional thunderstorms Wednesday afternoon, but it is too early to introduce any thunder into the TAF's. Extended Aviation Outlook: Flight restrictions possible in showers/thunderstorms each day, mainly in the afternoon/evening. && .MARINE... Tonight: No significant concerns as far as winds/seas but some stronger storms could cause locally hazardous conditions mainly after midnight. Wednesday through Saturday: No highlights are expected through the week. The waters will remain between Atlantic high pressure to the east and a broad area of lower pressure well inland. A weak upper low is expected to transition to a mid- level trough and move offshore by early Wednesday where convection could linger offshore. In general, southerly winds of 15 knots or less and seas of 3 feet or less are expected. An afternoon sea breeze will turn winds southerly/onshore near the coast each afternoon. Scattered showers and thunderstorms are expected mainly late night and early morning. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && NEAR TERM...BSH SHORT TERM...BRM LONG TERM...ETM AVIATION...BSH/BRM MARINE...RJB/BRM
Hazardous Weather Outlook National Weather Service Charleston SC 344 AM EDT Tue Aug 11 2020 AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040- 042>045-047>052-120745- 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 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- 344 AM EDT Tue Aug 11 2020 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...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time.
Special Weather Statement
National Weather Service Charleston SC
729 PM EDT Tue Aug 11 2020
GAZ138-120015-
Inland Liberty-
729 PM EDT Tue Aug 11 2020
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF LIBERTY COUNTY...
At 729 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near McIntosh, or 8 miles east of Fort Stewart,
moving southwest at 5 mph.
HAZARD...strong winds 45 to 55 mph.
IMPACT...Expect minor damage to tree limbs and blowing around of
light, unsecured objects.
Some locations in the path of this storm include...
Hinesville, Fort Stewart, McIntosh, Walthourville, Midway, Riceboro,
Flemington and Allenhurst.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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 3176 8164 3179 8165 3182 8170 3186 8170
3197 8147 3195 8146 3194 8140 3188 8139
3184 8137 3184 8136 3170 8147 3170 8150
TIME...MOT...LOC 2329Z 043DEG 5KT 3191 8147PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
756 PM EDT TUE AUG 11 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0618 PM HEAVY RAIN 3 NW CHARLESTON AIRPORT 32.93N 80.08W
08/11/2020 M1.23 INCH DORCHESTER SC COCORAHS
RAINFALL FELL IN AROUND 20 MINUTES.
&&
EVENT NUMBER CHS2000609
NEDThe Charleston,SC radar (KCLX), 100 km away, was scanning. The volume nearest the first event began at 00:02 UTC.
6 thunderstorm wind. Local standard time, as filed.
A social media post indicated a tree down on the road near the intersection of Niles Avenue and East 15th Street.
A picture shared via social media indicated damage to a garage door at a car dealership.
The Liberty County 911 Call Center reported a large limb down near the intersection of South Main Street and General Screven Way.
A power line and tree limb were reported down near the intersection of Pineland Avenue and Honey Ridge Lane.
A power line was reported down on the 600 block of McDowell Road.
Pictures via social media indicated roofing material on the ground from a business near the intersection of Pineland Avenue and Elma G Miles Parkway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2020Every state in 2020This day in weather historyWarnings in Georgia, August 2020
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: 916174, 916175, 916176, 916177, 916178, 916591.