North Carolina, 2017

Damaging Wind in North Carolina, August 7, 2017

August 7, 2017 · NWS GSP · 1 event in 1 county or zone

Scattered thunderstorms and storm clusters developed in the vicinity of a surface trough over Upstate South Carolina during the late afternoon and evening and moved into the North Carolina Piedmont during mid and late evening. One storm became briefly severe over the Charlotte area.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$100,000
Crop damage
None recorded
Events
1

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.

What happened

The episode as NWS GSP wrote it up.

Scattered thunderstorms and storm clusters developed in the vicinity of a surface trough over Upstate South Carolina during the late afternoon and evening and moved into the North Carolina Piedmont during mid and late evening. One storm became briefly severe over the Charlotte area.

What forecasters said that day

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 7, 9:35 PM EST, 7 minutes earlier.

Area forecast discussion, Aug 7, 9:35 PM EST, 7 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1035 PM EDT Mon Aug 7 2017

.SYNOPSIS...
A warm front will remain north of the area tonight as low pressure
moves from Tennessee to Virginia. The low pressure will move off
the New England Coast and pull the front back south over the forecast
area as a cold front tomorrow. 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 TUESDAY/...
As of 1035 PM EDT Monday:  Sct/Num convection continues to highlight
the weather across the region this evening.  Marginal cape amidst
~25kts 0-1km shear has allowed for a few strong storms across
portions of NE GA and the Carolinas along I85 this evening.
The strongest of which is currently approaching CLT metro packing
55-60mph winds along with with it.  Fortunately storm motions
this evening have been sufficient to alleviate any major hydro
concerns.  That said, looking at regional radar it is evident
that more convection is in line along/ahead of the stalled front.
The front will eventually begin its southern movement, however
in the meantime multiple rounds of convection are on order.
Pops were allowed to remain elevated, with the highest pops
associated with current tsra placement, as well as any upstream
convection expected to move into NE GA over the next few hours.
Pops were then allowed to fall below likely/cat levels into
early/mid morning as confidence in coverage is somewhat low.
Other than that, expecting mostly cloudy skies to dominate and
thereby keeping any widespread fog at bay, with only patchy fog
associated with earlier convection expected.  Tweaked t/td trends
through the night as well by way of blending in latest mos, which
effectively raised minT's over the piedmont by around a degree.

As of 230 PM: Muggy, unsettled weather conditions expected thru the
Near Term, as a cold front approaches from the north. A positively
tilted upper trough will dig over the Ohio Valley tonight, while
a sfc low pressure wave tracks across the Central Appalachians.
Forecast soundings show very moist air mass in place, with low LFC
heights and high freezing levels. Bulk shear is weakening and upper
forcing with the upper trough doesn't look strong enough to make for
real robust updrafts, as SBCAPE is only around 1500 J/kg. Where CAPE
is a little higher over the Midlands and Low Country, there are a
few strong storms. So I think severe threat is fairly low. The main
threat tonight into Tuesday will be locally heavy rain. But even
with this, I don't think things should get too out of hand. Will
continue to mention heavy rain in the HWO, given the very moist
air mass, and possibly some training convection. The highest QPF
is expected to be in the western NC mountains, where WSW upslope
flow helps enhance amounts of 1-2". The rest of the area should
see generally 0.5 to 0.75" amounts.

Overnight, convection should generally wane, but guidance does show
additional precip moving into the mountains from the west. This
activity should be fairly light, but embedded heavy downpours will
be possible. Temps will be slightly above normal under plenty of
cloud cover.

Tuesday, the overnight band of precip should continue to weaken as
it enters the piedmont early in the morning. At the surface, the
cold front should push in from the north and is expected to reach
the southern edge of the CWA by late morning. The NC mountains may
clear out enough for showers and storms to develop by early AFTN,
while the piedmont will take longer to see much clear behind the
front. Temps will be well below normal across the area under cloud
cover, closer to normal in the mountains with some clearing. Deep
convection, mainly showers and garden-variety tstms will be mainly
confined to the Blue Ridge. A small heavy rain threat will continue
due to the very moist air mass still in place.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 2:30 PM EDT Monday:  A post frontal trough, or secondary wind
shift line, will ease through our forecast area Tuesday evening. We
will be taking POPS down to slight chance, or lower by morning.

It appears the model suite is allowing a surface high to extend from
Illinois to Pennsylvania, and south into the Carolina's for mid
week. It almost has a mini wedge configuration. Low level moisture
should be abundant nevertheless, and we will start the diurnal
cycle for POPS, perhaps slightly abvoe average.

We start with a minimum in POPS Wednesday evening, but the upper
level flow starts to back and allow a return of moisture. Also a
wave train of vort maxes are embedded in the flow. The POPS for
Wednesday night still remain in the chance category, but edge up.

A bit more sharpening of upper level features Thursday should signal
an uptick in POP configuration, as a result we have brought values
up accordingly.

Overall through this portion of the forecast cycle, it appears to be
a lull in the amount and coverage of precipitation, considering the
constuction of the entire forecast package. However, we still have
to be on guard for heavy rain potential, although at least in this
part of the forecast cycle it appears to have eased somewhat.

As far as any severe potential, pulse type storms certainly look
possible Wednesday. Thursday we will probably begin having the
influence of some larger synoptic forcing.

Temperatures for this part of the forecast should remain be average,
which remains in line with the previous forecast and new data.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 210 PM EDT Monday: the extended fcst picks up at 00z on
Friday with a very broad, low amplitude upper trof centered over
Eastern Canada and upper ridging persisting over the Western CONUS
and well to our east over the sub-tropical Atlantic. 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. The upper trof axis is still not
expected to reach our area until the very end of the period, early
next week.

At the sfc, moist SLY return flow will be in place over the region
on Friday as a low slowly moves eastward across the Great Lakes and
brings its associated weak cold front towards the fcst area on Sat.
This scenario is about 24 hours faster than model runs this time
yesterday with the ECMWF being more progressive with the front than
the GFS. Beyond this point, the pattern evolution becomes more ambiguous
with the ECMWF trying to develop a secondary low in the wake of the
fropa late Sunday into early Monday and then quickly move that low
up the New England Coast. The GFS also tries to develop some sort of
weak system during this time frame, but it's not as coherent as the
ECMWF. Regardless, both models keep deeper moisture over the fcst
area thru the end of the period. 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.
The potential for isolated to widespread flooding remains elevated
with precipitable water fcst values 1 to 2 standard deviations above
normal thru most of the period. With the ample cloud cover expected,
high temps should remain a few degrees below normal with low temps
right around normal.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
At KCLT and Elsewhere: A mixture of VFR/MVFR and IFR likely at all
sites through this taf cycle as a warm/moist airmass remains across
the region while a quasistationary frontal axis sits just to the
nw.  With that, multiple rounds of convection are expected this
evening/tonight with tsra possible at the SC sites, likely weakening
to only shra when reaching the NC sites.  Therefore kept any ts
wording removed from KCLT, with only vcts for a few more hours at
the KHKY/KAVL, while holding on to vcts a bit longer at the SC
locales.  Otherwise, low VFR cigs will prevail outside of any
heavier convection through much of the evening/overnight before the
aforementioned stationary front shifts southward as a cold front,
likely moving into the NC high terrain in the 08z-10z time frame.
Cigs are expected to lower further with MVFR decks possible at all
locales ahead of and along the front as it slowly moves through the
region.  Precipitation will also be possible, however confidence in
timing/placement is low, therefore sites see only prob30s for such
with timing based on camguide.  The front will begin to clear the
region late in the period with sites recovering to VFR and drying
out from west to east, with winds veering nwly/nly post fropa.  The
only exception being at KAVL where guidance favors enough
destabilization behind the front to warrant a mention of tsra in a
prob30 during the afternoon hours.

Outlook: Unsettled conditions continue through most of the week
as a frontal boundary remains nearby, moisture pools, and a series
of upper level waves pass overhead. 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...

            02-08Z        08-14Z        14-20Z        20-00Z
KCLT       High 100%     High  93%     Med   65%     High  84%
KGSP       High 100%     High  98%     Med   77%     High  92%
KAVL       High  92%     Med   76%     Med   77%     High 100%
KHKY       High 100%     High  87%     High  88%     High  98%
KGMU       High 100%     High  96%     Med   69%     High 100%
KAND       High 100%     High  96%     Med   76%     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...ARK/CDG
SHORT TERM...TS
LONG TERM...JPT
AVIATION...CDG
Hazardous weather outlook, Aug 7, 3:58 PM EST, 5 hours 44 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
458 PM EDT Mon Aug 7 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-081100-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-
Rowan-Graham-Northern Jackson-Macon-Southern Jackson-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-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-
458 PM EDT Mon Aug 7 2017

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and upstate South Carolina.

.DAY ONE...Tonight.

Scattered to numerous showers and thunderstorms will periodically
move across the area tonight. The potential exists for these storms
to produce torrential rainfall. Some areas may experience multiple
rounds of such storms, resulting in locally significant accumulation
and possibly flash flooding.

In addition, a few of the storms could become severe with damaging
downburst winds the main threat. Cloud-to-ground lightning will be
noted as well. Move to a place of safety if storms approach.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

..Tuesday...Heavy rain possible. Numerous showers and thunderstorms
are expected again. This will keep the threat for heavy rainfall in
place across the area.
..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.
..Sunday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are requested to forward any reports of large hail,
damaging winds, or flash flooding to our office.

Sturey

In the hours before

Special weather statement, Aug 7, 8:38 PM EST, 1 hour 4 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
938 PM EDT MON AUG 7 2017

SCZ008-009-013-080215-
York SC-Cherokee SC-Union SC-
938 PM EDT MON AUG 7 2017

...A STRONG THUNDERSTORM WILL IMPACT WESTERN YORK...SOUTHEASTERN
CHEROKEE AND NORTHEASTERN UNION COUNTIES UNTIL 1015 PM EDT...

At 938 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles southeast of Gaffney, or 8 miles northeast of Jonesville,
moving northeast at 45 mph.

Locations to be impacted include...
York, Clover, Newport, Sharon, Hickory Grove, Smyrna, Kings Mountain
State Park, Bullock Creek, Saratt and Kings Creek.

Wind gusts up to 45 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 3494 8108 3482 8146 3482 8148 3478 8159
      3494 8170 3517 8138 3515 8114
TIME...MOT...LOC 0138Z 241DEG 41KT 3491 8156

HG
Special weather statement, Aug 7, 8:51 PM EST, 51 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
951 PM EDT MON AUG 7 2017

GAZ018-026-028-SCZ001-002-004-005-010-080215-
Hart GA-Franklin GA-Stephens GA-Pickens Mountains SC-
Greater Pickens SC-Greater Oconee SC-Anderson SC-Oconee Mountains SC-
951 PM EDT MON AUG 7 2017

...STRONG THUNDERSTORMS WILL IMPACT CENTRAL FRANKLIN...SOUTHEASTERN
STEPHENS...NORTHERN HART...NORTHWESTERN ANDERSON...WESTERN PICKENS
AND OCONEE COUNTIES UNTIL 1015 PM EDT...

At 951 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 4 miles northwest of Walhalla to 11 miles
southwest of Seneca to near Carnesville, and moving east at 35 mph.

Locations to be impacted include...
Clemson, Seneca, Hartwell, Walhalla, Carnesville, Central, Pendleton,
Westminster, Reed Creek and Lavonia.

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 3429 8336 3456 8317 3486 8319 3502 8278
      3467 8270 3436 8288 3428 8336
TIME...MOT...LOC 0151Z 252DEG 31KT 3482 8312 3458 8310 3437 8326

HG
Special weather statement, Aug 7, 9:07 PM EST, 35 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1007 PM EDT MON AUG 7 2017

SCZ009-014-080230-
York SC-Chester SC-
1007 PM EDT MON AUG 7 2017

...STRONG THUNDERSTORMS WILL IMPACT CHESTER AND SOUTHEASTERN YORK
COUNTIES UNTIL 1030 PM EDT...

At 1006 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 4 miles southeast of York to 8 miles northeast of
Chester to 15 miles northwest of Winnsboro, and moving northeast at
35 mph.

Locations to be impacted include...
Rock Hill, Chester, Fort Mill, Newport, Lesslie, Fort Lawn, Richburg,
Chester State Park, Catawba and Blackstock.

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 3464 8090 3460 8089 3455 8105 3457 8130
      3477 8119 3495 8122 3506 8090 3501 8091
      3499 8089 3492 8086 3490 8088 3484 8087
      3483 8090 3479 8088 3475 8088 3470 8086
TIME...MOT...LOC 0206Z 245DEG 28KT 3495 8118 3480 8113 3457 8125

HG
Special weather statement, Aug 7, 9:21 PM EST, 21 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1021 PM EDT MON AUG 7 2017

SCZ002-004-005-010-080245-
Pickens Mountains SC-Greater Pickens SC-Greater Oconee SC-
Anderson SC-
1021 PM EDT MON AUG 7 2017

...STRONG THUNDERSTORMS WILL IMPACT ANDERSON...PICKENS AND
SOUTHEASTERN OCONEE COUNTIES UNTIL 1045 PM EDT...

At 1021 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 10 miles west of Pickens to 3 miles north of
Clemson to 10 miles northwest of Anderson to 5 miles north of
Hartwell, and moving east at 25 mph.

Locations to be impacted include...
Anderson, Easley, Clemson, Seneca, Pickens, Homeland Park,
Powdersville, Piedmont, Belton and Central.

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 3435 8281 3437 8284 3444 8286 3448 8288
      3449 8291 3447 8301 3449 8304 3460 8300
      3472 8302 3481 8290 3493 8290 3500 8258
      3478 8245 3466 8247 3459 8242 3434 8266
TIME...MOT...LOC 0221Z 266DEG 23KT 3486 8290 3473 8282 3460 8280 3444
8295

HG
Special weather statement, Aug 7, 9:36 PM EST, 6 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1036 PM EDT MON AUG 7 2017

NCZ071-082-SCZ009-014-080300-
Union NC-Mecklenburg NC-York SC-Chester SC-
1036 PM EDT MON AUG 7 2017

...STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN MECKLENBURG...
UNION...NORTHEASTERN CHESTER AND SOUTHEASTERN YORK COUNTIES UNTIL
1100 PM EDT...

At 1036 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 8 miles northeast of Rock Hill to 20 miles west
of Monroe to 10 miles west of Lancaster, and moving east at 25 mph.

Locations to be impacted include...
Monroe, Rock Hill, South Charlotte, Matthews, Mint Hill, Indian
Trail, Weddington, Fort Mill, Stallings and Unionville.

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 8035 3481 8048 3482 8080 3494 8078
      3507 8091 3503 8090 3501 8091 3499 8089
      3492 8086 3490 8088 3484 8087 3483 8090
      3479 8088 3474 8087 3471 8100 3487 8096
      3504 8098 3524 8061 3505 8036
TIME...MOT...LOC 0236Z 263DEG 23KT 3503 8092 3488 8088 3472 8096

HG
Special weather statement, Aug 7, 9:41 PM EST, 1 minute before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1041 PM EDT MON AUG 7 2017

NCZ036-057-071-072-080330-
Rowan NC-Iredell NC-Cabarrus NC-Mecklenburg NC-
1041 PM EDT MON AUG 7 2017

...STRONG THUNDERSTORMS WILL IMPACT CABARRUS...SOUTHEASTERN
IREDELL...MECKLENBURG AND SOUTHWESTERN ROWAN COUNTIES UNTIL 1130 PM
EDT...

At 1041 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 10 miles southwest of Huntersville to 3 miles
southwest of Uptown Charlotte to 14 miles northeast of Rock Hill, and
moving northeast at 45 mph.

Locations to be impacted include...
Uptown Charlotte, Huntersville, Kannapolis, Downtown Concord, Central
Charlotte, South Charlotte, Northeast Charlotte, East Charlotte,
Northwest Charlotte and West Concord.

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.

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 3519 8051 3521 8055 3514 8063 3507 8084
      3520 8090 3534 8099 3536 8092 3537 8095
      3538 8096 3567 8072 3559 8043 3543 8034
TIME...MOT...LOC 0241Z 222DEG 39KT 3531 8097 3520 8090 3510 8085

HG

The radar

The Greer radar (KGSP), 129 km away, was scanning. The volume nearest the first event began at 02:41 UTC.

Open the radar archive at this moment

Event by event

1 thunderstorm wind. Local standard time, as filed.

Thunderstorm Wind, Mecklenburg

When
August 7, 9:42 PM EST
Where
Mecklenburg County, 1.22 mi SW of Charlotte to 2.74 mi ENE of Griffith
Measured
50 kt (58 mph) estimated gust
Property damage
$100,000
Reported by
911 Call Center
Coordinates
35.219, -80.867

County comms reported multiple trees blown down near Uptown and on the south side of the city, with trees on homes on Merriman Ave and in the Myers Park area.

What these are

Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in North Carolina in 2017Every state in 2017This day in weather historyWarnings in North Carolina, August 2017

Sources

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: 719333.