Daytime heating led to thunderstorms developing across the area, one of which produced severe wind gusts.
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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 CAE wrote it up.
Daytime heating led to thunderstorms developing across the area, one of which produced severe wind gusts.
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 Columbia, SC wrote its last area forecast discussion before the first event at Jul 17, 5:45 AM EST, 6 hours 43 minutes earlier.
Area Forecast Discussion National Weather Service Columbia SC 645 AM EDT Sat Jul 17 2021 .SYNOPSIS... A typical summertime pattern, with scattered afternoon and evening thunderstorms and seasonal temperatures, expected to continue through Saturday. A front will provide increased chances of showers and thunderstorms Sunday into early next week. Drier air is expected to filter into the region mid to late next week, providing less rain chances with near normal temperatures. && .NEAR TERM /THROUGH TONIGHT/... Little change in the pattern today although upper trough in the Mississippi Valley this morning will be moving a little closer to the region. Surface and upper ridge centered offshore SC extending into the region. Persistent Piedmont trough in place. Moisture remains high with precipitable water near 2 inches across the region. Moderate instability expected this afternoon again with CAPE around 2000 J/kg. Low to mid level lapse rates steep with strong insolation. Weak convergence expected across the area. A sea breeze may develop as well. With upper trough approaching there may be some weak short wave troughs in southwest flow aloft especially by early evening to enhance lift. 850mb winds appear to increase late in the west and north Midlands. Perhaps a few pulse severe storms possible into the evening. Heavy rain threat although a faster storm motion than yesterday expected. There may be a few showers this morning mainly CSRA but bulk of scattered convection this afternoon and evening. Showers should diminish overnight but may linger especially north and west. Persistence with temps...max in the low to mid 90s and lows in the low to mid 70s. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The axis of the 500mb trough will remain west of the area with a robust shortwave moving into the area leading to widespread showers and thunderstorms with PWATs similarly high. Will be a bit more difficult to get strong thunderstorms to develop in the western forecast area with the shortwave moving through in the morning but expect moderate destabilization in the eastern forecast area with lowering upper heights. Stronger steering flow should limit flooding concerns outside of training convection. Shear will be a bit stronger but still marginal for organized severe storms. Overall severe threat is low but an isolated severe storm remains possible in the far eastern forecast area. Precip chances will linger overnight unlike the past few days. Temperatures a bit lower in the western forecast area with highs in the upper 80s to low 90s in the eastern area. Monday, the axis of the 500mb trough pushes into the area with a surface cold front stalling in the northern forecast area. As a result expect more widespread convection developing through the day. Increased clouds and precipitation coverage will limit highs to the low to mid 80s. As a result, instability will be limited over the forecast area. With the stalled front and PWATs up to around 2 inches, heavy rain will be the main threat through the day. Similarly to Sunday night, expect precip chances to continue into Monday night. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Front remains stalled over the forecast area through midweek but with the trough axis shifting east of the forecast area with NW flow developing aloft. Low level moisture remains in place with some drier air filtering in aloft. Expect unsettled weather Tuesday and into Wednesday with convection becoming more diurnally driven. For the second half of the week, the front will become more diffuse with much more ensemble support of PWATs dropping to 1.5 inches or less which will significantly limit precip chances for Thursday and Friday. With a lack of precip and significantly cloud coverage as well as recovering 500mb heights, expect temperatures to rebound to near normal with highs into the mid 90s. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... Mainly VFR conditions expected although brief restrictions possible mainly this afternoon and evening associated with scattered thunderstorms. Surface and upper ridge centered offshore. Upper trough slowly approaching from the Mississippi Valley. Air mass remains quite moist and moderately unstable during the afternoon and early evening. Satellite this morning showing a few mid and high level clouds. There may be a few isolated showers this morning in the CSRA but impacts to terminals should be limited. Scattered cumulus developing by late morning possibly increasing in the afternoon as showers and thunderstorms develop. Convection should diminish by mid to late evening with mid level ceilings. Winds southwest 5 to 10 knots through the day. EXTENDED AVIATION OUTLOOK...Restrictions possible each day in diurnally driven showers and thunderstorms and early morning stratus/fog. Restrictions may be more widespread Sunday through Tuesday as a cold front moves into the area. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. &&
Hazardous Weather Outlook National Weather Service Columbia SC 411 AM EDT Sat Jul 17 2021 GAZ040-063>065-077-SCZ016-018-020>022-025>031-035-037-038-041-115- 116-135>137-180815- Lincoln-McDuffie-Columbia-Richmond-Burke-Chesterfield-McCormick- Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-Richland-Lee- Aiken-Sumter-Barnwell-Calhoun-Clarendon-Bamberg-Northern Lancaster- Southern Lancaster-Northwestern Orangeburg-Central Orangeburg- Southeastern Orangeburg- 411 AM EDT Sat Jul 17 2021 This Hazardous Weather Outlook is for the Midlands of South Carolina and the Central Savannah River area of Georgia. .DAY ONE...Today and tonight. Scattered thunderstorms developing this afternoon producing locally heavy rain with an isolated damaging wind gust possible. .DAYS TWO THROUGH SEVEN...Sunday through Friday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement
National Weather Service Columbia SC
1259 PM EDT Sat Jul 17 2021
SCZ027-028-037-171730-
Lexington SC-Calhoun SC-Richland SC-
1259 PM EDT Sat Jul 17 2021
...Strong Thunderstorms Will Impact Portions of east central
Lexington...northwestern Calhoun and south central Richland Counties
Until 130 PM EDT....
At 1259 PM EDT...National Weather Service doppler radar indicated a
strong thunderstorm near SC State Farmer's Market, or near Cayce,
moving east at 10 mph.
HAZARD...gusty winds 40 to 50 mph, pea sized hail, excessive cloud
to ground lightning and localized minor flooding.
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. Localized, minor flooding of low
lying and poor drainage areas is also possible.
Some locations in the path of this storm include...
Cayce, McEntire Air Base, SC State Farmer's Market, Congaree National
Park, Hopkins, Horrel Hill, Sandy Run, New Zion, Silver Lake,
Lexington Acres Pond and Dixiana.
Heavy rainfall is occurring with this storm, and may cause localized
flooding. Do not drive your vehicle through flooded roadways.
Move indoors immediately. Excessive cloud to ground lightning is
occurring with this storm. If you can hear thunder, you are close
enough to be struck by lightning.
This includes the following highways...
Interstate 26 between mile markers 117 and 124.
Interstate 77 between mile markers 2 and 4, and between mile markers
6 and 7.
LAT...LON 3382 8105 3386 8109 3392 8107 3395 8099
3399 8079 3376 8078
TIME...MOT...LOC 1659Z 264DEG 11KT 3390 8099
LCVSpecial Weather Statement
National Weather Service Columbia SC
109 PM EDT Sat Jul 17 2021
SCZ028-171800-
Richland SC-
109 PM EDT Sat Jul 17 2021
...Strong Thunderstorms Will Impact Portions of central Richland
County Until 200 PM EDT....
At 109 PM EDT...National Weather Service doppler radar indicated a
strong thunderstorm over Forest Acres, moving east at 15 mph.
HAZARD...gusty winds 40 to 50 mph, pea sized hail, excessive cloud
to ground lightning and localized minor flooding.
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. Localized, minor flooding of low
lying and poor drainage areas is also possible.
Some locations in the path of this storm include...
Columbia, Forest Acres, Dentsville, Arcadia Lakes, Woodfield,
Sesquicentennial State Park, Fort Jackson, Rosewood, Fort Jackson
Cantonment Area and Fort Jackson Wildcat Road.
Heavy rainfall is occurring with this storm, and may cause localized
flooding. Do not drive your vehicle through flooded roadways.
Move indoors immediately. Excessive cloud to ground lightning is
occurring with this storm. If you can hear thunder, you are close
enough to be struck by lightning.
This includes the following highways...
Interstate 20 in South Carolina between mile markers 73 and 82.
Interstate 77 between mile markers 9 and 17.
LAT...LON 3397 8100 3405 8101 3409 8094 3415 8083
3399 8078
TIME...MOT...LOC 1709Z 253DEG 11KT 3403 8094
LCVThe Columbia radar (KCAE), 18 km away, was scanning. The volume nearest the first event began at 17:27 UTC.
1 hail, 1 thunderstorm wind. Local standard time, as filed.
Photo shared on social media of pea sized hail near Spring Lake Rd in Forest Acres.
Sumter County Dispatch reported two trees down on Hwy 378 Eastbound coming out of the Black River Swamp beyond East Brewington Rd. The trees blocked one lane of traffic.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Carolina in 2021Every state in 2021This day in weather historyWarnings in South Carolina, July 2021
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 2026-09-30. Each event’s entry at NCEI: 960495, 960493.