Sufficient instability helped drive thunderstorm activity with notable outflow boundaries between high pressure offshore and a weak trough inland.
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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.
Sufficient instability helped drive thunderstorm activity with notable outflow boundaries between high pressure offshore and a weak trough inland.
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, 2:02 PM EST, 1 hour 53 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 302 PM EDT Sun Aug 13 2017 .SYNOPSIS... The area will remain situated between an inland trough and Atlantic high pressure through the week. && .NEAR TERM /THROUGH TONIGHT/... Convection has been pretty shallow so far this afternoon, despite modest instability and a robust sea breeze circulation. GOES-16 low/mid-level water vapor imagery suggest some mid- level subsidence may be occurring within a subtle dry pocket extending from near Charleston southwest into south-central Georgia. Still anticipate some interaction with convection developing across the Midlands later this afternoon and possible boundary collisions with additional convective cells that spark ahead of the sea breeze. Activity should diminish quickly this evening as instability wanes with the loss of insolation. However, with a moist, summer time airmass in place, some low- end mentionable pops will be held onto well into early Monday morning. Diurnal cumulus will diminish this evening with thin cirrus meandering through through from time to time aloft. Expect mostly clear to partly cloudy skies with lows dropping into the mid 70s inland to around 80 at the beaches. There are signals that some low stratus could develop across south-central Georgia early Monday and make a run for interior portions of Southeast Georgia right around daybreak. This will have to be watched carefully, but confidence in this scenario is too low to augment the sky forecast attm. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... The area will remain between an inland trough and offshore high pressure at the surface. High pressure will also build aloft. Deep moisture should persist through the period and in general the best rain chances should be across South Carolina closer to low pressure. A few strong to severe pulse-type storms are possible each afternoon but overall the chance appears low given the lack of significant bulk shear. Locally heavy rainfall will be possible however given the deep moisture and relatively light wind fields in place. Probably the main sensible weather highlight this period will be the high heat index values. High temperatures will generally warm through the period, staying above normal with mainly lower to mid 90s during the day and mid to upper 70s at night, with heat indices peaking near 105 degrees away from the immediate coast each afternoon. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Heights aloft will be on the rise through the second half of the week as stronger ridging develops across the Southeast. Low level flow will shift nearly due west in response to a surface ridge axis pushing into the area from the south, and temps will gradually climb through the period. Have generally sided with the warmer guidance given the pattern, bringing inland areas into the the mid-90s Friday and Saturday. Despite the downsloping pattern, enough moisture will remain to justify near climo pops most afternoons. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Primary concerns: * Tstm impacts VFR. KCLX radar shows showers/tstms beginning to develop across inland areas. Latest data suggest most of this will remain west of the terminals, although it may be close enough to KCHS for a VCTS. No direct impacts are anticipated attm, but trends are being monitored. An area of stratus could move into interior Southeast Georgia early Monday, but should remain west of KSAV. Extended Aviation Outlook: Afternoon/early evening showers/tstms each day. && .MARINE... Tonight: No concerns with southerly breezes less than 15 kt and seas 2-3 ft. Monday through Friday: The coastal waters will remain on the western periphery of Atlantic high pressure through the period, keeping generally southwest winds and minor swell in place. Tropical Depression 8 is expected to strengthen into a Tropical Storm as it passes well east of the local water Monday and Tuesday. Stay tuned to advisories from the National Hurricane Center for the latest on this system. && .EQUIPMENT... NOAA Weather Radio All Hazards station WWH-25 (162.425 MHz) broadcasting out of Metter, GA, remains off the air until further notice due to a long-duration phone outage. Return to service is unknown at this time. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. &&
Hazardous Weather Outlook National Weather Service Charleston SC 955 AM EDT Sun Aug 13 2017 AMZ330-350-352-354-374-GAZ114>119-137>141-141400- 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-Tattnall-Evans-Inland Bryan-Coastal Bryan-Inland Chatham- Coastal Chatham-Long-Inland Liberty-Coastal Liberty-Inland McIntosh- Coastal McIntosh- 955 AM EDT Sun Aug 13 2017 This Hazardous Weather Outlook is for Atlantic coastal waters and southeast Georgia. .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. GAZ087-088-099>101-SCZ040-042>045-047>052-141400- Jenkins-Screven-Candler-Bulloch-Effingham-Allendale-Hampton- Inland Colleton-Dorchester-Inland Berkeley-Inland Jasper-Beaufort- Coastal Colleton-Charleston-Coastal Jasper-Tidal Berkeley- 955 AM EDT Sun Aug 13 2017 ...ISOLATED SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING... This Hazardous Weather Outlook is for southeast Georgia and southeast South Carolina. .DAY ONE...Today and Tonight. Severe Thunderstorms: Scattered showers and thunderstorms will develop across much of Southeast South Carolina and Southeast Georgia this afternoon and linger into the early evening hours. A few of these thunderstorms will have the potential to become severe with damaging winds in excess of 60 mph. Locally heavy rainfall and frequent cloud to ground lightning will also possible. The risk for severe thunderstorms will be greatest between 2 pm and 7 pm. Be prepared to take action should threatening weather approach or if a warning is issued for your location. Stay tuned to NOAA Weather Radio, tv or your local news source for the latest statements and warnings from the National Weather Service. .DAYS TWO THROUGH SEVEN...Monday through Saturday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Please relay any reports of hazardous weather including, but not limited to large hail, damaging winds and flooding to the National Weather Service in Charleston at 1-888-383-2024.
Special Weather Statement
National Weather Service Charleston SC
244 PM EDT SUN AUG 13 2017
SCZ045-050-131915-
Inland Berkeley-Charleston-
244 PM EDT SUN AUG 13 2017
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON AND
BERKELEY COUNTIES...
At 244 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Awendaw, or 11 miles west of McClellanville,
moving north at 10 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...
Awendaw.
LAT...LON 3297 7964 3303 7975 3315 7972 3309 7955
TIME...MOT...LOC 1844Z 200DEG 7KT 3306 7967Special Weather Statement
National Weather Service Charleston SC
454 PM EDT SUN AUG 13 2017
SCZ047-048-051-132145-
Inland Jasper-Coastal Jasper-Beaufort-
454 PM EDT SUN AUG 13 2017
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BEAUFORT AND JASPER
COUNTIES...
At 453 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Coosawhatchie, or near Ridgeland, moving
east at 10 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...
Beaufort, Ridgeland, Clarendon, Grahamville, Coosawhatchie, Old
House, Laurel Bay and Sheldon.
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 3268 8083 3249 8069 3239 8095 3257 8107
3264 8093 3262 8092 3262 8090 3266 8087
TIME...MOT...LOC 2053Z 251DEG 9KT 3255 8091
DPBThe Charleston,SC radar (KCLX), 24 km away, was scanning. The volume nearest the first event began at 20:56 UTC.
1 thunderstorm wind. Local standard time, as filed.
The South Carolina Highway Patrol reported a tree down in the 7600 Block of Deerfield Road. The tree came down due to thunderstorm outflow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Carolina in 2017Every state in 2017This day in weather historyWarnings in South Carolina, August 2017
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: 717564.