Daytime heating allowed isolated severe thunderstorms to develop.
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 CAE wrote it up.
Daytime heating allowed isolated severe thunderstorms to develop.
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 20, 6:55 PM EST, 3 hours 10 minutes earlier.
Area Forecast Discussion National Weather Service Columbia SC 755 PM EDT Thu Jul 20 2017 .SYNOPSIS... An upper level ridge will prevail through the weekend. A cold front may bring more active weather during the early to middle part of next week. && .NEAR TERM /THROUGH FRIDAY/... Upper level low moving west over north Florida and southern Georgia toward panhandle. A few isolated showers and thunderstorms continue in the CSRA region but radar/satellite trends suggest weakening with loss of diurnal heating. Severe threat appears to be diminishing. So no pops overnight. Temperature forecast on track with lows in the low to mid 70s. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... A broad upper low over the central Gulf of Mexico will continue to be suppressed to the south while a broad upper ridge expands into the eastern United States. Meanwhile Bermuda high pressure will persist to the east. Fairly strong subsidence on Friday should limit the convective potential, though strengthening lee trough on Saturday may allow for a bit more coverage. Highs will be in the upper 90s both days with heat indices topping out around 108 in spots. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... The GFS and ECMWF display surface ridging extending from the Atlantic westward into the Gulf Coast during the medium-range period. North of the ridge lee-side troughing is shown in the forecast area. A slow moving cold front may be in the region Tuesday and Wednesday. The models display upper troughing developing early next week with increased moisture. The pattern supports an increasing thunderstorm chance during the period. The GFS and ECMWF MOS have pops 20 to 30 percent Sunday, and 30 to 40 percent during the rest of the period. The MOS continues to show hot conditions Sunday and Monday. Expect highs mainly 95 to 100 with heat index values near 105. Somewhat lower temperatures should occur during the rest of the medium- range period associated with upper troughing and more cloudiness. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... VFR conditions expected for a majority of the TAF period. Regional radar this evening shows isolated to scattered convection in the southeastern portion of the area. The activity is mainly south of CAE/CUB/OGB, but a few cells remain within the vicinity of DNL/AGS, so have continued with VCTS through 01Z. Convection will diminish with the loss of heating this evening. Models indicate a 25 knot low level jet developing overnight, so this should limit fog development. Confidence is too low to include at this time, but will continue to monitor fog potential. Ridging will prevail over the area on Friday which should limit convective potential. EXTENDED AVIATION OUTLOOK...No significant aviation related issues expected at this time. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Hazardous Weather Outlook National Weather Service Columbia SC Issued by National Weather Service CHARLESTON SC 339 PM EDT Thu Jul 20 2017 GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-211945- Lincoln-McDuffie-Columbia-Richmond-Burke-Lancaster-Chesterfield- McCormick-Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington- Richland-Lee-Aiken-Sumter-Barnwell-Orangeburg-Calhoun-Clarendon- Bamberg- 339 PM EDT Thu Jul 20 2017 This Hazardous Weather Outlook is for the Midlands of South Carolina and the Central Savannah River area of Georgia. .DAY ONE...This Afternoon and Tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
549 PM EDT THU JUL 20 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0458 PM TSTM WND DMG 5 E LIVINGSTON 33.54N 81.04W
07/20/2017 ORANGEBURG SC PUBLIC
PUBLIC REPORT OF 2 TREES DOWN AND VERY
STRONG WINDS.
&&
AWPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
613 PM EDT THU JUL 20 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0544 PM TSTM WND DMG 3 SSE BLACKVILLE 33.32N 81.26W
07/20/2017 BARNWELL SC 911 CALL CENTER
BARNWELL DISPATCH REPORTED TREES DOWN ON
POWERLINES ON HIGHWAY 304 OUTSIDE OF
BLACKVILLE.
&&
WRSThe Robins AFB radar (KJGX), 121 km away, was scanning. The volume nearest the first event began at 03:05 UTC.
1 thunderstorm wind. Local standard time, as filed.
Reports of tree limbs down, ranging in size from small to large, in Keysville and vicinity.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2017Every state in 2017This day in weather historyWarnings in Georgia, July 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: 714624.