Isolated thunderstorms developed during the evening in the vicinity of a warm front across Upstate South Carolina during the evening. One of the storms became briefly severe across Greenville County.
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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 GSP wrote it up.
Isolated thunderstorms developed during the evening in the vicinity of a warm front across Upstate South Carolina during the evening. One of the storms became briefly severe across Greenville County.
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 Greenville-Spartanburg, SC wrote its last area forecast discussion before the first event at Aug 6, 6:42 PM EST, 14 minutes earlier.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
742 PM EDT Sun Aug 6 2017
.SYNOPSIS...
A warm front will move north of the fcst area this evening and
remain north of the area on Monday as low pressure moves from
Texas across the Ohio Valley. The low pressure will move off the
New England Coast and pull the front back over the forecast area
as a cold front on Tuesday. The front is expected to stall again
across our region and remain through the end of the week, with
deep moisture and periods of heavy rain likely.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 730 PM EDT Sunday: Convection continues to roll across
portions of ne GA and the western Carolinas in association with an
old stationary front that is returning northward as a warm front.
With that, dewpoints and thus instability are maximized along/south
of I85 in conjunction with the current convection, which favors
mostly shra with a few embedded tsra. Still thinking the primary
concerns through the evening and overnight will be periods of
heavy rainfall which could eventually lead to flooding issues,
however in the immediate near term a few damaging wind gusts
associated with modest dcape and amidst the deepest convection
cant be ruled out. As for the fcst, tweaked t/td and pops to
align with recent obs/radar trends as well as latest cam guidance.
No other sig changes needed/made at this time.
Previous Discussion: Radar remains clear with a few showers having
popped-up south of the CWA in the last hour. Main features of
near-term synoptics are the approach of an upper trough and the
advance of surface moisture. These 2 things should combine for
showers tonight and Monday morning, and thunderstorms Monday
afternoon.
Latest surface analysis has some convective instability over
northeast GA and far western NC, with most better moisture confined
to the south of the CWA. As poorly defined surface boundary to the
south washes-out this afternoon and a weak surface trough forms
over the mountains, surface winds will become more southerly and
moisture will move northward. Surface dewpoints are expected to
advance 15 degrees between now and this time on Monday, with PWAT
values doubling from 1 inch now to 2 inches tomorrow. PVA from an
upper long-wave trough over the Eastern CONUS will also pass over
the area on Monday. These ingredients will give increasing chances
for rain this evening, with widespread rain and thunderstorms
on Monday. Heavier rain amounts are expected in the mountains,
but thunderstorms are more likely over the piedmont as instability
will be better to the south. Despite the advance of moisture,
forecast CAPE is still modest at 500 to 1000 j/kg of MLCAPE Monday
afternoon. Windshear, however, will be improving with up to 30kts
of 0-1km shear over western NC, which is also an area of low CAPE.
Surface delta-thetae from BUFKIT are also subdued through Monday,
so chances for severe are questionable. A quarter inch to an inch
of rain is anticipated on average with activity on Monday, with a
lot of variability depending on location of convective elements.
As rest of forecast has considerable rain in it, hydro concerns
will increase over time.
High temperatures Monday will be reduced due to extensive cloud
cover and precipitation.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 210 PM Sunday: The broad upper trough over the eastern Conus
will be reinforced early in the period by a short wave digging from
the Ohio Valley through the Mid-Atlantic. Attendant wavy cold front
is expected to be in, or at least just west of the forecast area at
the start of the period, supporting scattered to numerous coverage
of deep convection through Monday night. CAPE and deep-layer shear
are progged to be modest at best by mid-evening. Thus, whatever
severe convective threat exists Monday afternoon should diminish
quickly Monday evening. The front will slowly sag south through the
area on Tuesday, providing a focus for scattered to numerous showers
and thunderstorms. The buoyancy forecast for Tue afternoon is highly
uncertain at this point, as destabilization will be highly dependent
upon the extent of clouds and showers at the start of the day. (And
in fact, model guidance is all over the map regarding CAPE progs).
Therefore, it's about as clear as mud what the extent of any
convective threats will be Tuesday, but very high PWATs and
potential training of showers and storms along the slow-moving
boundary should yield at least a marginal threat of localized flash
flooding.
Abundant moisture remains in place across the area through the end
of the short term period. And although a slight diurnal trend
appears warranted due to the absence of strong forcing, at least
some degree of shower coverage should persist well into Tue night.
By the start of Wednesday, model guidance is in very good agreement
in moving the center of a 1024-ish mb surface high into the upper
Mid-Atlantic, with resultant ridging down the Eastern Seaboard now
expected to push the boundary south of the forecast area by that
time. The result will be a definitively more stable air mass for
Wed. However, guidance tends to develop a moist upslope/upglide flow
above the surface, warranting continued good chances for showers and
perhaps a few thunderstorms through Wednesday. Max temps will be
below normal and mins near to slightly above climo through the
period.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 2 PM EDT Sunday: the extended fcst picks up at 00z on Thursday
with a very broad upper trof centered over Eastern Canada and upper
ridging persisting over the Western CONUS and well to our east over
the sub-tropical Atlantic. A few weak, upper shortwaves will likely
pass over the fcst area early in the period with little change in the
large-scale pattern otherwise. As we move into the weekend, a more
amplified upper trof begins to dig down over the Northern Plains and
Western Great Lakes as the upper ridge persists over the Western CONUS.
At this point, the upper trof axis is not expected to reach our area
until early next week, which is beyond day 7.
At the sfc, a lingering frntl bndy is expected to move back northward
across the CWFA on Thursday as a warm front. Simultaneously, reinforcing
high pressure will be moving offshore putting us back under a moist, SLY
return-flow pattern for the end of the work week and into the weekend.
By the end of the period on Sunday, the models try to develop a low to
our NW and move its associated cold front towards the fcst area, however
it doesn't appear to reach the CWFA until late Sunday/early Monday.
As for the sensible fcst, precip chances will remain elevated thru the
period with high-end chance to low-end likely PoPs each day and broken
to overcast cloud cover thru the period. The potential for isolated to
widespread flooding remains elevated with Precip Water fcst values 1 to
2 standard deviations above normal thru the period. With the ample cloud
cover expected, high temps will start out at least a category below normal
and gradually warm thru the period with values just below climatology
by the end of the period.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
At KCLT and Elsewhere: A mixture of VFR/MVFR and possibly
IFR expected at all sites through this period as sly moisture
advection ahead of an approaching upper trof favors prolonged
sct/num convection. Initialized all sites based upon current radar
coverage/trends, which resulted in tempo's for KCLT/KGSP/KGMU as
iso tsra moves nely along the I85 corridor. Elsewhere, carried
vcts at KAND/KAVL with all other sites mentioning no wx in the
prevailing line. Beyond that, cam guidance favors multiple waves
of sct/num convection overnight as the llvs continue to moisten.
Therefore all sites will favor vcsh and eventually shra, with
tsra chances limited by way of nocturnal cooling/stabilization.
By morning all sites will have, or will be experiencing wx
with a modest llj favoring gusty swly winds from daybreak on.
Precipitation chances looks to dip a little in the late morning,
before the next round of convection swings into the region
by early/mid afternoon as the old stalled front lifts further
northward and PVA increases ahead of the upper trof.
Outlook: Unsettled conditions will set up through most of the
week as the boundary remains nearby, moisture pools overhead,
and a series of upper level waves pass by. Restrictions will be
possible with any showers and thunderstorms. Fog and low clouds
may develop each morning around daybreak, mainly in the mtn valleys
but also in areas that receive heavy rainfall the day before.
Confidence Table...
23-05Z 05-11Z 11-17Z 17-18Z
KCLT High 100% High 100% Med 70% High 100%
KGSP High 100% High 100% Med 63% Med 62%
KAVL High 100% High 83% High 90% Med 75%
KHKY High 100% High 100% High 85% Med 69%
KGMU High 100% High 100% High 80% Med 62%
KAND High 100% High 100% Med 78% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
SYNOPSIS...JPT
NEAR TERM...CDG/WJM
SHORT TERM...JDL
LONG TERM...JPT
AVIATION...CDGHazardous Weather Outlook National Weather Service Greenville-Spartanburg SC 539 PM EDT Sun Aug 6 2017 GAZ010-017-018-026-028-029-NCZ048-051>053-058-059-062>065-SCZ001>014- 019-072145- Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Madison-Swain-Haywood- Buncombe-Graham-Northern Jackson-Macon-Southern Jackson-Transylvania- Henderson-Oconee Mountains-Pickens Mountains-Greenville Mountains- Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg- Cherokee-York-Anderson-Abbeville-Laurens-Union-Chester-Greenwood- 539 PM EDT Sun Aug 6 2017 This Hazardous Weather Outlook is for northeast Georgia, western North Carolina and upstate South Carolina. .DAY ONE...Tonight. Scattered to numerous thunderstorms will continue to develop across the area through the overnight hours. Any of these storms will be capable of producing cloud-to-ground lightning and locally heavy rainfall. However, a couple of the storms may produce severe weather in the form of damaging wind gusts this evening. .DAYS TWO THROUGH SEVEN...Monday through Saturday. ..Monday...Heavy rain possible. Scattered thunderstorms are expected to develop within a very moist subtropical airmass. The potential exists for these storms to produce torrential rainfall. Furthermore, some areas may experience multiple rounds of such storms, resulting in locally significant accumulation. ..Tuesday...No hazardous weather is expected at this time. ..Wednesday...No hazardous weather is expected at this time. ..Thursday...No hazardous weather is expected at this time. ..Friday...No hazardous weather is expected at this time. ..Saturday...No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... None. NCZ033-035>037-049-050-056-057-068>072-082-501>510-072145- Avery-Alexander-Iredell-Davie-Yancey-Mitchell-Catawba-Rowan- Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union- Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke- McDowell Mountains-Eastern McDowell-Rutherford Mountains- Greater Rutherford-Polk Mountains-Eastern Polk- 539 PM EDT Sun Aug 6 2017 This Hazardous Weather Outlook is for piedmont North Carolina and western North Carolina. .DAY ONE...Tonight. Scattered to numerous thunderstorms will continue to develop across the area through the overnight hours. Any of these storms will be capable of producing cloud-to-ground lightning and locally heavy rainfall. .DAYS TWO THROUGH SEVEN...Monday through Saturday. ..Monday...Heavy rain possible. Scattered thunderstorms are expected to develop within a very moist subtropical airmass. The potential exists for these storms to produce torrential rainfall. Furthermore, some areas may experience multiple rounds of such storms, resulting in locally significant accumulation. ..Tuesday...No hazardous weather is expected at this time. ..Wednesday...No hazardous weather is expected at this time. ..Thursday...No hazardous weather is expected at this time. ..Friday...No hazardous weather is expected at this time. ..Saturday...No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... None. LANE
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
358 PM EDT SUN AUG 6 2017
SCZ019-062045-
Greenwood SC-
358 PM EDT SUN AUG 6 2017
...THUNDERSTORMS WILL PRODUCE VERY HEAVY RAINFALL OVER EXTREME
SOUTHEASTERN GREENWOOD COUNTY THROUGH 445 PM EDT...
At 354 PM EDT, Doppler radar was tracking a series of thunderstorms
and rain showers repeatedly producing heavy rainfall over
southeastern Greenwood County, generally east of a line from Dyson
to Kirksey. These thunderstorms were moving northeast at 5 to 10
mph, but back-building to the southwest to keep the heavy rainfall
locked in place.
Radar indicated rainfall rates of 1 to 2 inches per hour in the
heaviest downpours. Localized flooding of low-lying and poor
drainage areas will be possible in the vicinity of Kirksey and
Dyson.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.
&&
LAT...LON 3398 8205 3398 8211 3420 8193 3418 8192
3418 8191 3416 8191 3415 8190 3413 8187
3410 8190 3409 8192 3404 8194 3400 8199
3397 8201 3395 8205
TIME...MOT...LOC 1954Z 208DEG 9KT 3403 8200
HGSpecial Weather Statement National Weather Service Greenville-Spartanburg SC 646 PM EDT SUN AUG 6 2017 NCZ082-062315- Union NC- 646 PM EDT SUN AUG 6 2017 ...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN UNION COUNTY UNTIL 715 PM EDT... At 645 PM EDT, Doppler radar was tracking a strong thunderstorm 10 miles northeast of Lancaster, or 8 miles south of Mineral Springs, moving northeast at 20 mph. Locations to be impacted include... Monroe, Wingate, Mineral Springs, Unionville, Indian Trail, Trinity and Jaars. Wind gusts up to 40 mph will be possible in these areas. PRECAUTIONARY/PREPAREDNESS ACTIONS... Gusty winds can blow down trees that are dead, or that have weakened root systems. Outdoor furniture and similar items can be tossed around if not anchored. Seek shelter indoors. && LAT...LON 3493 8033 3481 8046 3482 8077 3509 8060 TIME...MOT...LOC 2245Z 216DEG 17KT 3482 8065 HG
Special Weather Statement National Weather Service Greenville-Spartanburg SC 651 PM EDT SUN AUG 6 2017 SCZ006-010-062315- Anderson SC-Greater Greenville SC- 651 PM EDT SUN AUG 6 2017 ...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN GREENVILLE AND NORTHEASTERN ANDERSON COUNTIES UNTIL 715 PM EDT... At 651 PM EDT, Doppler radar was tracking a strong thunderstorm 10 miles northeast of Anderson, or over Williamston. This storm was moving northeast at 5 to 10 mph. Locations to be impacted include... Powdersville, Piedmont, Belton, Williamston, West Pelzer, Donaldson Center and Fork Shoals. Wind gusts up to 40 mph and very heavy rainfall rates of 1 to 2 inches per hour will be possible in these areas. PRECAUTIONARY/PREPAREDNESS ACTIONS... Gusty winds can blow down trees that are dead, or that have weakened root systems. Outdoor furniture and similar items can be tossed around if not anchored. Seek shelter indoors. && LAT...LON 3461 8263 3482 8249 3466 8228 3450 8246 TIME...MOT...LOC 2251Z 217DEG 3KT 3462 8250 HG
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
713 PM EDT SUN AUG 6 2017
NCZ082-062345-
Union NC-
713 PM EDT SUN AUG 6 2017
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN UNION COUNTY UNTIL
745 PM EDT...
At 713 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Monroe, or 6 miles south of Wingate, moving
northeast at 20 mph.
Locations to be impacted include...
Monroe, Wingate, Marshville, Sturdivants and Trinity.
Wind gusts up to 40 mph and very heavy rainfall rates of 1 to 2
inches per hour will be possible in these areas.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.
&&
LAT...LON 3484 8032 3481 8038 3482 8053 3492 8062
3515 8032 3511 8029
TIME...MOT...LOC 2313Z 235DEG 19KT 3489 8049
HGSpecial Weather Statement
National Weather Service Greenville-Spartanburg SC
722 PM EDT SUN AUG 6 2017
SCZ006-007-012-062345-
Laurens SC-Spartanburg SC-Greater Greenville SC-
722 PM EDT SUN AUG 6 2017
...STRONG THUNDERSTORMS WILL IMPACT NORTHERN LAURENS...GREENVILLE
AND SOUTHWESTERN SPARTANBURG COUNTIES UNTIL 745 PM EDT...
At 721 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from near Greenville Downtown to 18 miles southeast
of Easley to 15 miles northwest of Laurens, and moving northeast at
15 to 20 mph.
Locations to be impacted include...
Greenville Downtown, Greenville Eastside, West Greenville, Greer,
Mauldin, Taylors, Simpsonville, Berea, Five Forks and Fountain Inn.
Wind gusts up to 40 mph will be possible in these areas.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.
&&
LAT...LON 3450 8228 3465 8233 3482 8248 3483 8248
3483 8249 3484 8248 3484 8249 3488 8249
3501 8240 3506 8223 3488 8212 3469 8199
TIME...MOT...LOC 2321Z 219DEG 17KT 3484 8242 3470 8229 3462 8226
HGSpecial Weather Statement
National Weather Service Greenville-Spartanburg SC
724 PM EDT SUN AUG 6 2017
SCZ001-002-070000-
Pickens Mountains SC-Oconee Mountains SC-
724 PM EDT SUN AUG 6 2017
...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN PICKENS AND
NORTHEASTERN OCONEE COUNTIES UNTIL 800 PM EDT...
At 723 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Walhalla, or near Salem, moving northeast at 20
mph.
Locations to be impacted include...
Salem, Devils Fork State Park, Lake Keowee, Keowee Toxaway State
Park, Jocassee Gorges, Oconee State Park, Lake Jocassee, Sunset, Bad
Creek and Nine Times.
Wind gusts up to 40 mph and pea size hail will be possible in these
areas.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.
&&
LAT...LON 3501 8307 3507 8283 3502 8272 3479 8292
3477 8295 3485 8314
TIME...MOT...LOC 2323Z 208DEG 17KT 3488 8300
HGThe Greer radar (KGSP), 15 km away, was scanning. The volume nearest the first event began at 23:57 UTC.
1 thunderstorm wind. Local standard time, as filed.
FD reported a tree blown down on power lines at the intersection of Highway 14 and Mount Lebanon Church Road and another tree down on Jordan Rd.
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: 719331.