Alert archive / North Carolina / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 117, NWS Greenville-Spartanburg, SC

August 11, 2021Union County, North Carolina

NWS Greenville-Spartanburg, SC issued this severe thunderstorm warning at Aug 11, 2021, 5:34 PM EDT for Union County, North 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 outline as issued.

The facts

Issued
Aug 11, 2021, 5:34 PM EDT (21:34 UTC)
Expired
Aug 11, 2021, 6:01 PM EDT
In force
27 min
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Union County, NC

The radar

The Columbia radar (KCAE), 137 km from the middle of the area, began a volume at 21:37 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 9.6 hours before the alert went out and 125 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 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 653 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 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
653 J/kg
Mixed-layer CIN
-106 J/kg
Mixed-layer LCL
1352 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
-21 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

807 
WUUS52 KGSP 112134
SVRGSP
NCC179-112215-
/O.NEW.KGSP.SV.W.0117.210811T2134Z-210811T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Greenville-Spartanburg SC
534 PM EDT Wed Aug 11 2021

The National Weather Service in Greenville-Spartanburg has issued a

* Severe Thunderstorm Warning for...
  Northeastern Union County in the Piedmont of North Carolina...

* Until 615 PM EDT.

* At 534 PM EDT, a severe thunderstorm was located 9 miles north of
  Monroe, or near Fairview In Union County, and is nearly stationary.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor hail damage to vehicles is expected. Expect wind 
           damage to trees and power lines.

* Locations impacted include...
  Monroe, Unionville, Lake Park, Hemby Bridge, Fairview In Union
  County, Indian Trail and Stallings.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Brief damaging winds will blow down trees and power lines over small
areas. A brief period of large hail is also possible. Seek shelter
inside an interior room.

Please report damaging winds, hail, or flooding to the National
Weather Service by calling toll free, 1, 800, 2 6 7, 8 1 0 1, or by
posting on our Facebook page, or Tweet it using hashtag nwsgsp. Your
message should describe the event and the specific location where it
occurred.

&&

LAT...LON 3496 8060 3513 8065 3515 8062 3520 8052
      3518 8050 3502 8037
TIME...MOT...LOC 2134Z 338DEG 4KT 3512 8055 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

KRENTZ
1 follow-up statement
380 
WWUS52 KGSP 112201
SVSGSP

Severe Weather Statement
National Weather Service Greenville-Spartanburg SC
601 PM EDT Wed Aug 11 2021

NCC179-112211-
/O.CAN.KGSP.SV.W.0117.000000T0000Z-210811T2215Z/
Union NC-
601 PM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN UNION COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

LAT...LON 3496 8060 3513 8065 3515 8062 3520 8052
      3518 8050 3502 8037
TIME...MOT...LOC 2157Z 338DEG 4KT 3509 8054 

$$

KRENTZ

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 11, 2:57 PM EDT, 2 hours 37 minutes earlier.

Area forecast discussion, Aug 11, 2:57 PM EDT, 2 hours 37 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
257 PM EDT Wed Aug 11 2021

.SYNOPSIS...
Abundant moisture will wrap around Atlantic high pressure and into
our area through Friday, bringing daily shower and thunderstorm
chances. A cold front will stall over the area this weekend, and the
remnants of Tropical Storm Fred may arrive early next week, possibly
resulting in periods of heavy rainfall Saturday through Monday.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 240 PM EDT Wednesday: We've already seen some robust cells
fire up over the higher terrain and foothills over the past few
hours, with coverage expected to increase thru the late afternoon
and into the evening with similar (or slightly greater) overall
coverage compared to yesterday. Otherwise, expect little change
in the overall environment today, with the sub-tropical ridge
firmly over the Southeast and an associated Bermuda High sfc
pattern. So expect another hot and muggy day, with scattered
to numerous aftn showers and thunderstorms. A few storms will
likely pulse up to severe levels, with the main threat being
damaging wind gusts. There will also continue to be a non-zero
flash flood threat, given the high PWATs and slow storm motions
expected. Tonight, convection should wane during the early evening
hours, leaving plenty of mid and high clouds that gradually thin
out overnight. Mountain valley fog will likely develop, with some
of it possibly being dense. Lows will be slightly above normal.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 215 PM Wed: Mid level ridging will remain in place across the
region Thursday night through Saturday. This will keep temperatures
slightly above normal with highs in the lower to middle 90s in the
Piedmont and mid to upper 80s in the mountain valleys. Scattered
showers and thunderstorms are expected mainly during the afternoon
and evening hours both Friday and Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 215 PM Wed: A seasonably weak cold front will approach the
area from the north on Sunday. This will lead to an increased focus
for showers and thunderstorms on Sunday so pops will be fairly high
especially in the mountains. Based on the latest NHC track for Fred,
expect increased deep moisture to overspread the area on Monday and
Tuesday which may lead to some heavy rainfall especially in the
favored upslope areas. If the forecast for Fred changes, that would
lower the chance for heavy rainfall.

With the increased cloud cover and rainfall from Sunday into early
next week, expect highs to be in the 80s except for the higher
mountains.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: Outside of the typical, diurnally-driven
summertime convection, I expect VFR conditions to prevail at most
sites thru the taf period. We've already seen some fairly robust
cells fire up over the higher terrain over the past couple of hours,
and I expect the coverage to increase thru the afternoon and into
the evening with similar (or slightly greater) overall coverage
compared to yesterday. Winds should remain generally light out of
the SW thru the period, except in the vicinity of thunderstorms.
Another round of mountain valley fog and patchy fog elsewhere is
expected again overnight and tomorrow morning, as winds remain light
and skies gradually clear out.

Outlook: Diurnal convection remains in the fcst for the rest of the
week. Fog and low stratus will be possible each morning, especially
over mountain valleys and areas primed by rainfall from the previous
evening.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High  95%     Low   51%     Med   77%
KHKY       High 100%     High 100%     High  80%     High  95%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High  95%     High  95%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...SCW
NEAR TERM...JPT
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...JPT
Hazardous weather outlook, Aug 11, 4:11 PM EDT, 1 hour 23 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
411 PM EDT Wed Aug 11 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-122015-
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 NC-
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-Union SC-Chester-Greenwood-
411 PM EDT Wed Aug 11 2021

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

.DAY ONE...Tonight.

Scattered thunderstorms will continue this afternoon into this
evening across portions of the forecast area. Some of these storms
could become strong to severe. Main impacts are cloud-to-ground
lightning, brief damaging wind gusts, and heavy downpours which may
lead to localized flash flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

In the hours before

Special weather statement, Aug 11, 4:35 PM EDT, 59 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
435 PM EDT Wed Aug 11 2021

SCZ010-112100-
Anderson SC-
435 PM EDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of south central
Anderson County through 500 PM EDT...

At 435 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles south of Anderson, or near Homeland Park. This storm was nearly
stationary.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Anderson, Homeland Park, Iva, Starr, Anderson Airport and Broadway
Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3431 8279 3433 8279 3435 8281 3447 8280
      3451 8258 3436 8251 3431 8259 3428 8277
TIME...MOT...LOC 2035Z 350DEG 3KT 3443 8268

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

TDP
Special weather statement, Aug 11, 4:51 PM EDT, 43 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
451 PM EDT Wed Aug 11 2021

SCZ006-112115-
Greater Greenville SC-
451 PM EDT Wed Aug 11 2021

...A THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT SOUTHERN
GREENVILLE COUNTY UNTIL 515 PM EDT...

At 450 PM EDT, Doppler radar was tracking a thunderstorm with intense
lightning 13 miles south of Greenville Downtown, or near West Pelzer,
moving south at 10 mph.

Locations to be impacted include...
Piedmont and Fork Shoals.

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.

Frequent lightning is occurring with this storm. If outdoors, try to
get indoors or into a hard topped vehicle. Otherwise, stay away from
open areas and isolated high objects such as trees. When indoors,
stay away from windows and doors and avoid using wired electronic
devices. Do not take a shower or bath. Try to unplug unnecessary
appliances before the storm approaches.

&&

LAT...LON 3459 8242 3462 8245 3464 8245 3467 8247
      3468 8246 3471 8247 3471 8246 3472 8247
      3475 8246 3470 8227 3460 8229 3457 8232
      3456 8242
TIME...MOT...LOC 2050Z 016DEG 9KT 3466 8241

TDP
Special weather statement, Aug 11, 4:54 PM EDT, 40 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
454 PM EDT Wed Aug 11 2021

NCZ068-508-112130-
Greater Rutherford NC-Cleveland NC-
454 PM EDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of northeastern
Rutherford and west central Cleveland Counties through 530 PM EDT...

At 453 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles northeast of Forest City, or near Bostic. This storm was nearly
stationary.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Polkville, Ellenboro, Bostic, Kingstown, Sunshine and Caroleen.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3528 8179 3543 8192 3557 8178 3536 8158
TIME...MOT...LOC 2053Z 232DEG 1KT 3540 8179

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

WJM
Special weather statement, Aug 11, 5:02 PM EDT, 32 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
502 PM EDT Wed Aug 11 2021

NCZ036-057-112130-
Rowan NC-Iredell NC-
502 PM EDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of east central Iredell
and northwestern Rowan Counties through 530 PM EDT...

At 501 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Statesville, or near Cleveland. This storm was
nearly stationary.

HAZARD...Winds in excess of 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Statesville, Cleveland, Piedmont Research Station, Mount Ulla, Cool
Springs and Woodleaf.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3567 8052 3560 8073 3574 8086 3589 8072
      3587 8071 3585 8071 3585 8070 3586 8070
      3586 8069
TIME...MOT...LOC 2101Z 232DEG 1KT 3572 8073

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

WJM
Local storm report, Aug 11, 5:30 PM EDT, 4 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
530 PM EDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0411 PM     TSTM WND DMG     3 SSW UNION GROVE       35.99N 80.87W
08/11/2021                   IREDELL            NC   EMERGENCY MNGR

            EMERGENCY MNGR REPORTED TREES DOWN ON TRUMPET BRANCH
            RD.

&&
Special weather statement, Aug 11, 5:33 PM EDT, 1 minute before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
533 PM EDT Wed Aug 11 2021

GAZ028-029-SCZ010-112200-
Elbert GA-Hart GA-Anderson SC-
533 PM EDT Wed Aug 11 2021

...A CLUSTER OF THUNDERSTORMS WITH INTENSE LIGHTNING WILL IMPACT
NORTH CENTRAL ELBERT...SOUTHEASTERN HART AND SOUTHEASTERN ANDERSON
COUNTIES UNTIL 600 PM EDT...

At 533 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms with intense lightning along a line extending from
11 miles east of Anderson to 9 miles northeast of Elberton, and
moving south at 5 mph.

Locations to be impacted include...
Anderson, Homeland Park, Belton, Honea Path, Iva, Starr, Lake
Russell, Rock Branch, Nuberg and Broadway Lake.

In addition to intense lightning, 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.

Frequent lightning is occurring with these storms. If outdoors, try
to get indoors or into a hard topped vehicle. Otherwise, stay away
from open areas and isolated high objects such as trees. When
indoors, stay away from windows and doors and avoid using wired
electronic devices. Do not take a shower or bath. Try to unplug
unnecessary appliances before the storms approach.

&&

LAT...LON 3414 8282 3428 8298 3457 8252 3446 8236
      3421 8274 3420 8274
TIME...MOT...LOC 2133Z 347DEG 5KT 3448 8246 3423 8279

TDP

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 12:28 PM EDTSpecial Weather StatementGSPHenderson47 min
Aug 11, 1:47 PM EDTSpecial Weather StatementGSPMcDowell28 min
Aug 11, 2:51 PM EDTSpecial Weather StatementGSPBurke24 min
Aug 11, 3:01 PM EDTSevere Thunderstorm WarningGSPBurke, Catawba44 min
Aug 11, 3:24 PM EDTSpecial Weather StatementGSPPolk36 min
Aug 11, 3:51 PM EDTSevere Thunderstorm WarningGSPBuncombe39 min
Aug 11, 3:53 PM EDTSevere Thunderstorm WarningGSPIredell52 min
Aug 11, 4:01 PM EDTSevere Thunderstorm WarningGSPPolk44 min
Aug 11, 4:03 PM EDTSevere Thunderstorm WarningGSPBurke, Cleveland, Lincoln, Rutherford42 min
Aug 11, 4:24 PM EDTSpecial Weather StatementGSPRutherford36 min
Aug 11, 4:31 PM EDTSpecial Weather StatementGSPIredell29 min
Aug 11, 4:40 PM EDTSevere Thunderstorm WarningGSPCatawba, Iredell50 min
Aug 11, 4:54 PM EDTSpecial Weather StatementGSPRutherford36 min
Aug 11, 5:02 PM EDTSpecial Weather StatementGSPIredell28 min
Aug 11, 5:08 PM EDTSevere Thunderstorm WarningGSPIredell, Rowan34 min
Aug 11, 5:17 PM EDTSevere Thunderstorm WarningGSPCleveland43 min
Aug 11, 5:46 PM EDTSpecial Weather StatementGSPMecklenburg29 min
Aug 11, 5:57 PM EDTSpecial Weather StatementGSPMecklenburg33 min
Aug 11, 6:08 PM EDTSevere Thunderstorm WarningGSPMecklenburg10 min
Aug 11, 6:10 PM EDTSpecial Weather StatementGSPGaston35 min
Aug 11, 6:16 PM EDTSpecial Weather StatementGSPCabarrus29 min
Aug 11, 6:29 PM EDTSevere Thunderstorm WarningGSPCabarrus20 min
Aug 11, 6:47 PM EDTSpecial Weather StatementGSPCabarrus28 min
Aug 11, 6:59 PM EDTAreal Flood AdvisoryGSPCabarrus, Rowan2 hr
Aug 11, 7:28 PM EDTSpecial Weather StatementGSPMecklenburg32 min
Aug 11, 7:31 PM EDTSevere Thunderstorm WarningGSPMecklenburg44 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 2021Every severe thunderstorm warning in 2021

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.