Alert archive / North Carolina / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 316, NWS Greenville-Spartanburg, SC

August 31, 2018Mecklenburg County, North Carolina; York County, South Carolina

NWS Greenville-Spartanburg, SC issued this severe thunderstorm warning at Aug 31, 2018, 5:18 PM EDT for Mecklenburg County, North Carolina; York County, South Carolina. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 31, 2018, 5:18 PM EDT (21:18 UTC)
Expired
Aug 31, 2018, 5:45 PM EDT
In force
27 min
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Mecklenburg County, NC, York County, SC

The radar

The Greer radar (KGSP), 113 km from the middle of the area, began a volume at 21:19 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 9.3 hours before the alert went out and 147 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 12:00Z on 2018-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 482 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 12:00Z on 2018-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
482 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 31, 3:02 PM EDT, 2 hours 16 minutes earlier.

Area forecast discussion, Aug 31, 3:02 PM EDT, 2 hours 16 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
302 PM EDT Fri Aug 31 2018

.SYNOPSIS...
A strong upper-level ridge will dominate the eastern United States
through the entire period, resulting in above-normal temperatures
and reduced precip chances outside of the mountains.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 235 PM: Convection continues to favor the NC Mountains and
Foothills along with a smaller area over the NW Piedmont and the
eastern CLT Metro. Convection currently isolated elsewhere. Expect
the convection to fill in across the rest of the area but remain low
end scattered at best. Atmos is still very unstable with high DCAPE
values, especially outside of the mountains. With light shear in
place, don't expect any organized severe storms, but isolated
damaging wind gusts are quite possible. Isolated flood threat
continues as well with high PW values and slowly moving storms. The
southerly storm motion is also a concern as storms may move across
the same areas, especially in the higher terrain. The convection
should diminish this evening with the loss of heating.

The weakness in the upper pattern is erased Saturday as upper
ridging builds west over the Southeast CONUS. This means less short
wave energy rotating over the area. This should also bring an end to
the steeper lapse rates we've seen the past couple of days. That
said, instability and high moisture levels continue keeping diurnal
convection in the forecast. Coverage should be similar to the past
couple of days with highest chance over the mountains and lowest
chance over NE GA and the western Upstate.

Lows tonight and highs Saturday will be a few degrees above normal.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 245 PM Fri: Since the previous issuance, there has been very
little change to the overall forecasted pattern through the end
of the extended period Saturday morning during what is thankfully
a benign pattern for this time of year.  The upper-level ridge,
which has been largely absent across the eastern ConUS all summer,
will retrograde slightly west and and amplify Sunday into Monday
Its presence should induce subsidence warming as indicated by
forecast profiles (700-800mb cap) which should provide enough
inhibition to limit most diurnal convective coverage to the
climatologically favorable ridge tops.  With negligible steering
flow and PWs in the 75th-90th percentile for this time of year,
any pulse convection will be capable of producing heavy rainfall.
Strong downburst winds will also be possible as the convection
collapses.  Max temperatures will be generally 2-5 degrees above
normal with min temps 4-7 degrees above normal.  Dewpoints outside
of the mountains will stagnate around 70 with very little mixing
to reduce humidity values during the afternoon.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 245 PM Fri: As mentioned above, the overall pattern will
persist through the end of the extended on Saturday morning
with the heat ridge peaking mid-week over the Mid-Atlantic.
Slight convective chances will persist, with the highest
chances remaining over the ridge tops as subsidence should limit
convection over the Pidemont.  Little change to total moisture
content through the period will mean the threat for isolated
heavy rainfall will also persist given the slow-moving activity.
Temperatures will remain above-normal through mid-week; however,
flow will become more northeasterly around the southern extent of
the high pressure heading into late week which may advect slightly
cooler air into the region as the upper-ridge starts to break
down somewhat.  Any sensible weather changes will be very modest
with max temperatures returning to near normal, low temperatures
remaining above normal, and PoPs largely unchanged.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Convection developing across the area with
better coverage across the mountains. Enough current coverage and
chance through the afternoon for VCTS and TEMPO for TSRA at all
sites but KCLT. Convection is developing east of KCLT, so convection
may need to be added during the scheduled updates. Convection
dissipates during the evening. Looks like another good night for
mountain valley fog. MVFR fog possible at KHKY/KAND toward morning.
Once the fog burns off, cumulus develops for Saturday afternoon.
Light S to SW wind this afternoon becomes light and variable this
evening. Light SW wind for Saturday.

Outlook: Scattered diurnal showers and thunderstorms are expected
each afternoon Sunday through Tuesday. Areas of fog and low stratus
can also be expected each morning, primarily in the mtn valleys.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High 100%     High 100%     High  96%     High  96%
KGSP       High 100%     High 100%     High  96%     High  96%
KAVL       High 100%     High  93%     Med   60%     High  92%
KHKY       High 100%     High 100%     High  90%     High  96%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     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...JMP
NEAR TERM...RWH
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...RWH
Hazardous weather outlook, Aug 31, 4:03 AM EDT, 13 hours 15 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
403 AM EDT Fri Aug 31 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-010815-
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-
403 AM EDT Fri Aug 31 2018

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

.DAY ONE...Today and tonight.

Scattered thunderstorms are in the forecast today and tonight. The
storms will be most widespread during the afternoon and early
evening. Cloud-to-ground lightning is possible with any of these
thunderstorms, along with torrential rainfall. A few of the storms
could also produce severe weather, in the form of damaging wind.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Wimberley

In the hours before

Special weather statement, Aug 31, 3:47 PM EDT, 1 hour 31 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
347 PM EDT FRI AUG 31 2018

NCZ033-312015-
Avery NC-
347 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL AVERY COUNTY UNTIL 415
PM EDT...

At 347 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles northeast of Newland, or over Sugar Mountain, moving north at 5
mph.

Locations to be impacted include...
Newland, Banner Elk, Sugar Mountain, Seven Devils, Grandfather
Mountain State Park, Grandfather Mountain, Beech Mountain In Avery
County and B.R. Parkway-Linville Falls To Grandfather.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 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 3621 8191 3619 8189 3619 8186 3616 8183
      3611 8181 3611 8180 3608 8181 3608 8192
      3622 8197 3623 8196 3623 8191
TIME...MOT...LOC 1947Z 177DEG 5KT 3613 8188

MOORE
Special weather statement, Aug 31, 4:39 PM EDT, 39 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
439 PM EDT FRI AUG 31 2018

SCZ009-312115-
York SC-
439 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL YORK COUNTY UNTIL
515 PM EDT...

At 439 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles northeast of Rock Hill, or over Fort Mill, moving north at 5
mph.

Locations to be impacted include...
Rock Hill, Fort Mill, Tega Cay, Lesslie and Carowinds.

Wind gusts up to 40 mph, half inch hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3490 8088 3487 8088 3488 8098 3495 8102
      3505 8103 3511 8093 3506 8090 3503 8090
      3501 8091 3499 8089 3497 8089 3496 8087
      3492 8086
TIME...MOT...LOC 2039Z 177DEG 5KT 3500 8094

MOORE
Special weather statement, Aug 31, 4:44 PM EDT, 34 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
444 PM EDT FRI AUG 31 2018

NCZ071-312115-
Mecklenburg NC-
444 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT WESTERN MECKLENBURG COUNTY UNTIL
515 PM EDT...

At 444 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles west of Uptown Charlotte, or over Charlotte Douglas Airport,
moving north at 5 mph.

Locations to be impacted include...
Uptown Charlotte, Huntersville, Central Charlotte, Northeast
Charlotte, Southwest Charlotte, Northwest Charlotte, Pineville,
Freedom Park, Charlotte Douglas Airport and Steele Creek.

Wind gusts up to 45 mph, pea size hail and very heavy rainfall rates
up to 2 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.

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3503 8087 3511 8093 3505 8103 3515 8102
      3516 8100 3517 8100 3522 8101 3530 8101
      3533 8098 3534 8099 3535 8097 3535 8096
      3536 8092 3536 8093 3537 8096 3542 8086
      3532 8078
TIME...MOT...LOC 2044Z 177DEG 5KT 3521 8094

MOORE
Local storm report, Aug 31, 5:05 PM EDT, 13 minutes before
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Special weather statement, Aug 31, 5:06 PM EDT, 12 minutes before
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Special weather statement, Aug 31, 5:11 PM EDT, 7 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
511 PM EDT FRI AUG 31 2018

NCZ057-312145-
Rowan NC-
511 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL ROWAN COUNTY UNTIL
545 PM EDT...

At 511 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles south of Salisbury, or near Faith, moving north at 10 mph.

Locations to be impacted include...
Salisbury, China Grove, Granite Quarry, Rockwell, Faith, Spencer and
High Rock Lake.

Wind gusts up to 45 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3551 8039 3553 8059 3570 8059 3568 8033
TIME...MOT...LOC 2111Z 185DEG 8KT 3559 8049

MOORE

The office that day

Everything else NWS Greenville-Spartanburg, SC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 30, 9:46 PM EDTSpecial Weather StatementGSPRowan29 min
Aug 30, 9:48 PM EDTSevere Thunderstorm WarningGSPCabarrus, Rowan42 min
Aug 30, 9:54 PM EDTSpecial Weather StatementGSPAlexander36 min
Aug 30, 10:30 PM EDTSevere Thunderstorm WarningGSPDavie, Rowan45 min
Aug 30, 11:12 PM EDTSpecial Weather StatementGSPMecklenburg33 min
Aug 30, 11:41 PM EDTSpecial Weather StatementGSPCatawba34 min
Aug 30, 11:57 PM EDTSpecial Weather StatementGSPMecklenburg33 min
Aug 31, 12:15 AM EDTSpecial Weather StatementGSPCatawba30 min
Aug 31, 12:58 AM EDTSpecial Weather StatementGSPIredell32 min
Aug 31, 1:28 AM EDTSpecial Weather StatementGSPDavie32 min
Aug 31, 3:21 PM EDTSpecial Weather StatementGSPUnion24 min
Aug 31, 3:47 PM EDTSpecial Weather StatementGSPAvery28 min
Aug 31, 4:44 PM EDTSpecial Weather StatementGSPMecklenburg31 min
Aug 31, 5:02 PM EDTSevere Thunderstorm WarningGSPMecklenburg28 min
Aug 31, 5:06 PM EDTSpecial Weather StatementGSPBurke24 min
Aug 31, 5:11 PM EDTSpecial Weather StatementGSPRowan34 min
Aug 31, 5:46 PM EDTSevere Thunderstorm WarningGSPGaston44 min
Aug 31, 5:49 PM EDTSpecial Weather StatementGSPRowan26 min
Aug 31, 5:56 PM EDTSpecial Weather StatementGSPLincoln34 min
Aug 31, 6:10 PM EDTSevere Thunderstorm WarningGSPLincoln35 min
Aug 31, 6:20 PM EDTSevere Thunderstorm WarningGSPCleveland21 min
Aug 31, 6:25 PM EDTSpecial Weather StatementGSPCatawba35 min
Aug 31, 6:30 PM EDTSevere Thunderstorm WarningGSPGaston, Lincoln20 min
Aug 31, 6:35 PM EDTSpecial Weather StatementGSPBurke25 min
Aug 31, 6:43 PM EDTSpecial Weather StatementGSPCleveland32 min
Aug 31, 6:46 PM EDTSevere Thunderstorm WarningGSPCatawba44 min
Aug 31, 7:22 PM EDTSevere Thunderstorm WarningGSPCatawba, Lincoln23 min
Aug 31, 7:29 PM EDTSpecial Weather StatementGSPAlexander31 min
Aug 31, 7:49 PM EDTSpecial Weather StatementGSPAlexander26 min
Aug 30, 10:21 PM EDTSpecial Weather StatementGSPYork24 min
Aug 31, 4:39 PM EDTSpecial Weather StatementGSPYork36 min
Aug 31, 6:04 PM EDTSpecial Weather StatementGSPYork26 min
Aug 31, 7:07 PM EDTSpecial Weather StatementGSPCherokee23 min
Aug 31, 7:11 PM EDTSevere Thunderstorm WarningGSPCherokee, Chester, York22 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 2018Severe Thunderstorm Warnings in South Carolina, 2018Every severe thunderstorm warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.