Alert archive / North Carolina / Tornado Watches in 2021

Tornado Watch 444

August 17, 20214 counties in Georgia; 26 counties in North Carolina; 24 counties in South Carolina

The Storm Prediction Center issued this tornado watch at Aug 17, 2021, 10:42 AM EDT for 4 counties in Georgia; 26 counties in North Carolina; 24 counties in South Carolina. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Aug 17, 2021, 10:42 AM EDT (14:42 UTC)
Expired
Aug 17, 2021, 6:37 PM EDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 54 counties

Columbia County, GA, Lincoln County, GA, McDuffie County, GA, Rabun County, GA, Alexander County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mecklenburg County, NC, Mitchell County, NC, Polk County, NC, Rowan County, NC, Rutherford County, NC, Transylvania County, NC, Union County, NC, Yancey County, NC, Abbeville County, SC, Aiken County, SC, Anderson County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Cherokee County, SC, Chester County, SC, Edgefield County, SC, Fairfield County, SC, Greenville County, SC, Greenwood County, SC, Laurens County, SC, Lexington County, SC, McCormick County, SC, Newberry County, SC, Oconee County, SC, Orangeburg County, SC, Pickens County, SC, Richland County, SC, Saluda County, SC, Spartanburg County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 28 km from the middle of the area, began a volume at 14:47 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

58 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 17, 11:36 AM EDTTornado Warning Tornado observedGSPAlexander, Iredell39 min
Aug 17, 11:47 AM EDTTornado WarningGSPHabersham, Rabun, Stephens13 min
Aug 17, 11:52 AM EDTFlash Flood WarningGSPHabersham, Rabun5 hr
Aug 17, 12:06 PM EDTTornado WarningGSPIredell39 min
Aug 17, 12:30 PM EDTFlash Flood WarningGSPOconee5 hr
Aug 17, 12:30 PM EDTTornado WarningGSPOconee, Pickens23 min
Aug 17, 12:33 PM EDTTornado WarningGSPAlexander12 min
Aug 17, 12:42 PM EDTTornado Warning Tornado observedGSPIredell18 min
Aug 17, 12:59 PM EDTTornado WarningCAEEdgefield46 min
Aug 17, 12:59 PM EDTTornado WarningGSPAnderson, Pickens23 min
Aug 17, 1:09 PM EDTFlash Flood WarningGSPJackson, Macon, Transylvania5 hr
Aug 17, 1:20 PM EDTTornado WarningGSPPickens25 min
Aug 17, 1:25 PM EDTFlash Flood WarningGSPTransylvania4 hr
Aug 17, 1:44 PM EDTTornado WarningCAEEdgefield, McCormick, Saluda17 min
Aug 17, 1:55 PM EDTTornado WarningCAEAiken, Edgefield, Lexington, Saluda50 min
Aug 17, 2:03 PM EDTFlash Flood WarningGSPGreenville, Pickens5 hr
Aug 17, 2:08 PM EDTTornado WarningCAEAiken37 min
Aug 17, 2:14 PM EDTTornado WarningGSPGreenwood, Laurens33 min
Aug 17, 2:31 PM EDTTornado WarningGSPRabun19 min
Aug 17, 2:31 PM EDTTornado WarningGSPBurke, Caldwell44 min
Aug 17, 2:31 PM EDTTornado WarningCAEBarnwell44 min
Aug 17, 2:52 PM EDTTornado WarningGSPGreenville26 min
Aug 17, 3:01 PM EDTTornado Warning Tornado observedGSPGreenville18 min
Aug 17, 3:02 PM EDTTornado WarningGSPCaldwell43 min
Aug 17, 3:06 PM EDTTornado WarningGSPAlexander, Caldwell39 min
Aug 17, 3:12 PM EDTFlash Flood WarningGSPHaywood3 hr
Aug 17, 3:12 PM EDTTornado WarningCAELexington, Saluda48 min
Aug 17, 3:41 PM EDTFlash Flood WarningGSPBuncombe5 hr
Aug 17, 3:48 PM EDTTornado WarningGSPAlexander, Burke, Caldwell, Catawba42 min
Aug 17, 3:48 PM EDTTornado WarningCAEFairfield, Lexington, Newberry, Richland42 min
Aug 17, 4:07 PM EDTTornado WarningGSPAvery, Burke, McDowell, Mitchell53 min
Aug 17, 4:08 PM EDTFlash Flood WarningGSPMadison9 hr
Aug 17, 4:16 PM EDTFlash Flood WarningGSPBuncombe, Henderson5 hr
Aug 17, 4:17 PM EDTTornado WarningGSPAvery, Burke, Caldwell43 min
Aug 17, 4:20 PM EDTTornado WarningGSPHenderson, Polk, Rutherford12 min
Aug 17, 4:24 PM EDTFlash Flood Warning Considerable damage threatGSPHaywood4 hr
Aug 17, 4:25 PM EDTSevere Thunderstorm WarningCAEFairfield, Newberry50 min
Aug 17, 4:35 PM EDTFlash Flood WarningGSPBuncombe, Henderson, Polk, Rutherford8 hr
Aug 17, 4:48 PM EDTSevere Thunderstorm WarningCAEBamberg, Orangeburg42 min
Aug 17, 4:50 PM EDTFlash Flood WarningGSPMcDowell9 hr
Aug 17, 4:56 PM EDTTornado WarningCAEOrangeburg34 min
Aug 17, 4:58 PM EDTFlash Flood WarningGSPYancey4 hr
Aug 17, 4:59 PM EDTTornado WarningGSPAvery, Burke, McDowell, Mitchell, Yancey46 min
Aug 17, 5:08 PM EDTTornado WarningGSPAnderson, Greenville, Pickens52 min
Aug 17, 5:10 PM EDTTornado WarningGSPAbbeville, Greenville, Greenwood, Laurens50 min
Aug 17, 5:11 PM EDTTornado WarningGSPAbbeville, Greenwood, Laurens49 min
Aug 17, 5:14 PM EDTFlash Flood Warning Considerable damage threatGSPTransylvania4 hr
Aug 17, 5:26 PM EDTTornado WarningGSPAvery, McDowell, Mitchell, Rutherford, Yancey49 min
Aug 17, 5:28 PM EDTTornado WarningGSPAvery, Burke, Caldwell47 min
Aug 17, 5:29 PM EDTTornado WarningCAECalhoun, Orangeburg46 min
Aug 17, 5:32 PM EDTFlash Flood WarningGSPMitchell4 hr
Aug 17, 5:33 PM EDTTornado WarningGSPAnderson, Greenville, Spartanburg42 min
Aug 17, 5:37 PM EDTTornado WarningGSPChester, York38 min
Aug 17, 5:57 PM EDTTornado WarningGSPGreenville, Laurens, Spartanburg48 min
Aug 17, 5:58 PM EDTTornado WarningGSPGreenwood, Laurens47 min
Aug 17, 6:00 PM EDTFlash Flood WarningGSPAvery, Burke, Caldwell9 hr
Aug 17, 6:15 PM EDTTornado WarningGSPLaurens, Spartanburg, Union45 min
Aug 17, 6:16 PM EDTFlash Flood WarningGSPHenderson, Polk, Rutherford3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 2.7 hours before the alert went out and 245 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 2021-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 522 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 2021-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.193958Sfc1 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
522 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

644 
WWUS20 KWNS 171439
SEL4  
SPC WW 171439
GAZ000-NCZ000-SCZ000-172300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 444
NWS Storm Prediction Center Norman OK
1040 AM EDT Tue Aug 17 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northeast Georgia
  Western North Carolina
  Western South Carolina

* Effective this Tuesday morning and evening from 1040 AM until
  700 PM EDT.

* Primary threats include...
  A few tornadoes likely
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...The remnants of Fred will continue to track northward
across Georgia, with bands of thunderstorms affecting the watch
area.  Isolated tornadoes and gusty winds will be possible through
the day.

The tornado watch area is approximately along and 60 statute miles
either side of a line from 35 miles west northwest of Asheville NC
to 65 miles south southeast of Spartanburg SC. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU4).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 443...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 16025.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 3:13 AM EDTMesoscale DiscussionSPCBibb, Butts, Crawford, Henry, Houston, Jasper and 8 more2 hr
Aug 17, 3:45 AM EDTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Butts and 49 more9 hr
Aug 17, 8:22 AM EDTMesoscale DiscussionSPCBanks, Clarke, Columbia, Elbert, Franklin, Glascock and 12 more113 min
Aug 17, 12:35 PM EDTMesoscale DiscussionSPCAlexander, Cabarrus, Catawba, Cleveland, Davie, Forsyth and 9 more85 min
Aug 17, 1:06 PM EDTTornado WatchSPCAlleghany, Ashe, Rockingham, Stokes, Surry, Watauga and 2 more5 hr
Aug 17, 3:25 PM EDTMesoscale DiscussionSPCBuncombe, Burke, Cleveland, Gaston, Henderson, Lincoln and 4 more2 hr
Aug 17, 5:55 PM EDTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 28 more65 min
Aug 17, 6:28 PM EDTTornado WatchSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 24 more10 hr

Nearby

Tornado Watches in North Carolina, 2021Tornado Watches in South Carolina, 2021Tornado Watches in Georgia, 2021Every tornado watch 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.