Scattered thunderstorms developed across the North Carolina Piedmont in the vicinity of a stationary front during the afternoon and evening. One of the storms produced brief damaging winds in Rowan 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.
Scattered thunderstorms developed across the North Carolina Piedmont in the vicinity of a stationary front during the afternoon and evening. One of the storms produced brief damaging winds in Rowan 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 12, 5:20 PM EST, 26 minutes earlier.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
620 PM EDT Sun Aug 12 2018
.SYNOPSIS...
A low level boundary will remain stalled across the Piedmont and aide
in developing afternoon showers and thunderstorms which will
linger into the evening. An upper-level disturbance will track
northeast the region late Monday leading to drier weather Tuesday
and Wednesday. Moisture levels increase Thursday through the end of
the week ahead of an approaching cold front.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 600 PM...Tstm chances through mid-evening will be confined
mainly to locales east of the Blue Ridge and NE of I-26 and there
also remains the likelihood of isolated strong storms producing stout
wind gusts and/or torrential rainfall. Later tonight, as an upper
low wobbles around the OH/PA border, vort energy remains progged to
pivot downstream of the cwfa. This should carry any lingering
convection east of the FA by late evening. Some mid and high clouds
will linger under the circulation of the upper low, but mountain
valleys will likely fog up overnight. Low temps will be about a
category above normal.
Monday, the upper low will wobble eastward bringing NVA and deep-
layer Q-vector divergence atop the FA. Dry air will also wrap in
from the west, with dewpts dipping into 60s for most of the area.
This all adds up to much less sbCAPE and a break from the active
convective pattern we've been in. Guidance does try to fire at least
a few isolated showers in the high terrain, and cannot rule out a
few showers or storm in the far eastern zones, depending on how fast
we dry out before peak heating. Temps will be near normal under
partly cloudy skies.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 2pm EDT Sunday: Fairly quiet short term forecast as region
will be between systems. A few lingering showers are possible
Monday night over the mountains as upper wave exits, but these will
be on the decline as frontal boundary pushes moisture further
southeast. Tuesday will see gradual height rises on the dry side of
upper system with convectively stable and capped air mass in place
by Tuesday evening. Ridge builds over the area on Wednesday and
begins to move east by late Wednesday when some clouds and possibly
a few showers out west ahead of next system may be entering the
region. Conditions Tuesday and Wednesday will generally be clear and
seasonally normal with fairly light winds with a slight
northwesterly bias when not variable.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 300 PM EDT Sunday: Thursday PoPs are generally unchanged from
yesterday and overnight with a slower progression of the previously
advertised shortwave. The slower forecast can be attributed to
additional retrogression of the large subtropical ridge into the
SE US and NE GoMex.
Diurnal PoPs on Friday have increased slightly over the mountains
closer to the approaching "cold" front and mid-level support
via the dampening shortwave, but guidance is also significantly
decreasing coverage over the Piedmont compared to yesterday, which
may be premature given height falls across the entire region in
advance of the shortwave trough and the lingering presence of
a lee trough. However, timing may be an issue over the Piedmont
as the better forcing may not arrive until after peak heating.
Let's see if a trend develops first before removing low-end chance
PoPs over the Piedmont.
Convective chances still are expected to increase over the Piedmont
on Saturday as the aforementioned weak cold front sags into the
area underneath a reinforced shortwave trough, although this too
appears to be about 6-12 hours slower than yesterday's forecast.
This too is a blend of a faster GFS solution and slower ECMWF
and Canadian guidance. Given the proximity of upper support and
the presence of the weak surface convergence high-end chance PoPs
are maintained over the mountains while chance PoPs are maintained
further east through the weekend. Throughout the extended, moisture
transport from the GoMex remains anemic as the source remains on
the western edge of the ridge axis and flow is weak. The GFS is
suggesting lower total water content compared to yesterday but
plenty of in-situ moisture remains and it would not take much
flux to introduce PWs near 2" east of the mountains at any point.
Therefore, a localized heavy rain threat will persist at a minimum.
Temperatures will remain at or perhaps 1-3 degrees below normal
through the extended. Dewpoints will remain in the upper 60s
to lower 70s east of the mountains keeping humidity values high
through the period.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Convection should gradually drift east from
the Blue Ridge escarpment across the NC Piedmont this aftn into
early evening. KHKY and KCLT will likely have some direct impacts
from TSRA, which will be handled with TEMPOs. Most of the convection
looks to stay east of the other TAF sites, but will go with VCTS for
the late aftn and early evening hours. Convection should exit east
of the area by late evening, with some VFR-level cloudiness
lingering thru the overnight. Mountain valley fog and stratus is
expected late tonight thru daybreak Monday. Patchy fog will be
possible east of the mountains, especially the NC Piedmont. Monday
looks like a much quieter day convection-wise. A few isolated
showers may develop across the mountains and to the east of KCLT in
the aftn. No precip mention will be carried at any of the TAF sites
for Monday. Winds will be light thru the period, other than with
potential tstm wind gusts.
Outlook: Drier weather is expected for Tuesday and Wednesday, but
will be followed by a return of diurnal convection on Thursday and
Friday.
Confidence Table...
22-04Z 04-10Z 10-16Z 16-18Z
KCLT High 100% High 100% Med 75% High 92%
KGSP High 97% High 100% High 100% High 100%
KAVL High 100% High 100% Med 72% High 96%
KHKY High 100% High 94% High 97% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 91% 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...SBK
NEAR TERM...ARK/CSH
SHORT TERM...WJM
LONG TERM...JMP
AVIATION...ARKHazardous Weather Outlook National Weather Service Greenville-Spartanburg SC 604 PM EDT Sun Aug 12 2018 NCZ035>037-056-057-064-065-068>072-082-501>510-SCZ002-003-005>009- 012>014-132215- Alexander-Iredell-Davie-Catawba-Rowan-Transylvania-Henderson- 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-Pickens Mountains- Greenville Mountains-Greater Pickens-Greater Greenville-Spartanburg- Cherokee-York-Laurens-Chester- 604 PM EDT Sun Aug 12 2018 This Hazardous Weather Outlook is for piedmont North Carolina, western North Carolina and upstate South Carolina. .DAY ONE...Tonight. There is the ongoing threat of thunderstorm development this evening. A few of these storms could still become severe with damaging wind gusts. Isolated flooding will also be possible. Any storm will be capable of producing strong wind gusts, heavy rainfall, and cloud to ground lightning. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotters are requested to forward any reports of large hail, damaging winds, tornadoes, or flash flooding to our office. GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062-063-SCZ001-004- 010-011-019-132215- Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey- Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon- Southern Jackson-Oconee Mountains-Greater Oconee-Anderson-Abbeville- Greenwood- 604 PM EDT Sun Aug 12 2018 This Hazardous Weather Outlook is for northeast Georgia, western North Carolina and upstate South Carolina. .DAY ONE...Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... None.
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
532 PM EDT SUN AUG 12 2018
NCZ064-065-SCZ003-122200-
Transylvania NC-Henderson NC-Greenville Mountains SC-
532 PM EDT SUN AUG 12 2018
...A CLUSTER OF THUNDERSTORMS WILL IMPACT EAST CENTRAL
TRANSYLVANIA...SOUTH CENTRAL HENDERSON AND NORTH CENTRAL GREENVILLE
COUNTIES UNTIL 600 PM EDT...
At 531 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 11 miles southwest of
Columbus to 10 miles south of Hendersonville to 7 miles east of
Brevard, and moving south at 5 mph.
Locations to be impacted include...
Dupont State Forest, Flat Rock, Jones Gap State Park, Little River In
Transylvania County, North Saluda Reservoir, Tuxedo and Crab Creek.
Wind gusts up to 45 mph, pea size hail and torrential rainfall rates
up to 3 inches per hour will be possible in these areas.
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 3514 8235 3512 8249 3517 8264 3528 8263
3527 8248 3526 8238
TIME...MOT...LOC 2131Z 357DEG 5KT 3518 8239 3517 8249 3521 8260
LANESpecial Weather Statement
National Weather Service Greenville-Spartanburg SC
548 PM EDT SUN AUG 12 2018
NCZ057-122215-
Rowan NC-
548 PM EDT SUN AUG 12 2018
...A STRONG THUNDERSTORM WILL IMPACT CENTRAL ROWAN COUNTY UNTIL 615
PM EDT...
At 548 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles northwest of Salisbury, moving east at 20 mph.
Locations to be impacted include...
Salisbury.
Wind gusts up to 45 mph and pea size hail will be possible in these
areas.
LAT...LON 3568 8060 3574 8063 3578 8052 3578 8050
3577 8049 3578 8048 3577 8047 3573 8045
3569 8044
TIME...MOT...LOC 2148Z 249DEG 18KT 3573 8055
LANESpecial Weather Statement National Weather Service Greenville-Spartanburg SC 556 PM EDT SUN AUG 12 2018 NCZ072-122215- Cabarrus NC- 556 PM EDT SUN AUG 12 2018 ...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CABARRUS COUNTY UNTIL 615 PM EDT... At 555 PM EDT, Doppler radar was tracking a strong thunderstorm near Downtown Concord, moving northeast at 5 mph. Locations to be impacted include... Concord. Wind gusts up to 50 mph, pea size hail and torrential rainfall rates up to 3 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. 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 3534 8060 3538 8066 3548 8057 3537 8046 TIME...MOT...LOC 2155Z 226DEG 6KT 3540 8056 LANE
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
601 PM EDT SUN AUG 12 2018
SCZ003-122230-
Greenville Mountains SC-
601 PM EDT SUN AUG 12 2018
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GREENVILLE COUNTY
UNTIL 630 PM EDT...
At 601 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles southwest of Columbus, or 5 miles north of Tigerville, moving
southeast at 15 mph.
Locations to be impacted include...
Tigerville, Glassy Mountain, North Saluda Reservoir and Gowensville.
Wind gusts up to 50 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 3517 8245 3517 8244 3519 8242 3521 8239
3520 8238 3519 8238 3518 8237 3519 8235
3519 8232 3510 8222 3508 8222 3501 8239
3501 8240
TIME...MOT...LOC 2201Z 318DEG 12KT 3514 8236
LANESpecial Weather Statement National Weather Service Greenville-Spartanburg SC 623 PM EDT SUN AUG 12 2018 NCZ057-072-122300- Rowan NC-Cabarrus NC- 623 PM EDT SUN AUG 12 2018 ...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CABARRUS AND SOUTH CENTRAL ROWAN COUNTIES UNTIL 700 PM EDT... At 623 PM EDT, Doppler radar was tracking a strong thunderstorm 8 miles east of Kannapolis, or 5 miles southwest of Rockwell, moving northeast at 10 mph. This storm will remain over mainly rural areas of north central Cabarrus and south central Rowan Counties. Wind gusts up to 50 mph and half inch 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 3541 8051 3547 8056 3558 8044 3547 8036 TIME...MOT...LOC 2223Z 227DEG 9KT 3549 8047 LANE
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
625 PM EDT SUN AUG 12 2018
NCZ057-122245-
Rowan NC-
625 PM EDT SUN AUG 12 2018
...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL ROWAN COUNTY UNTIL
645 PM EDT...
At 624 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles east of Salisbury, or over High Rock Lake, moving northeast at
15 mph.
Locations to be impacted include...
High Rock Lake.
Wind gusts up to 50 mph and half inch 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.
High Rock Lake is in the path of this storm. Cloud to ground
lightning and gusty winds will create dangerous boating conditions.
Move to shore immediately.
&&
LAT...LON 3561 8036 3567 8039 3572 8033 3571 8032
3570 8033 3568 8033 3567 8031 3563 8029
3563 8027 3561 8024
TIME...MOT...LOC 2224Z 242DEG 12KT 3566 8030
LANEThe national radar mosaic for the moment the first event began.
1 thunderstorm wind. Local standard time, as filed.
Public reported multiple trees and large limbs blown down in and near Rockwell.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Carolina in 2018Every state in 2018This day in weather historyWarnings in North Carolina, August 2018
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: 782126.