Alert archive / South Carolina / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 150
The Storm Prediction Center issued this severe thunderstorm watch at May 4, 2021, 4:56 PM EDT for 4 counties in Georgia; 13 counties in North Carolina; 19 counties in South Carolina. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- May 4, 2021, 4:56 PM EDT (20:56 UTC)
- Expired
- May 4, 2021, 8:15 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 36 counties
Burke County, GA, Columbia County, GA, McDuffie County, GA, Richmond County, GA, Anson County, NC, Bladen County, NC, Cumberland County, NC, Harnett County, NC, Hoke County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Richmond County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Aiken County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Edgefield County, SC, Florence County, SC, Kershaw County, SC, Lee County, SC, Lexington County, SC, Marion County, SC, Marlboro County, SC, Orangeburg County, SC, Richland County, SC, Saluda County, SC, Sumter County, SC
The radar
The Columbia radar (KCAE), 30 km from the middle of the area, began a volume at 20:58 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 5:03 PM EDT | Severe Thunderstorm Warning | CAE | Chesterfield, Kershaw, Lancaster, Lee | 57 min |
| May 4, 5:08 PM EDT | Severe Thunderstorm Warning | ILM | Darlington, Marlboro | 52 min |
| May 4, 5:30 PM EDT | Severe Thunderstorm Warning | CAE | Burke, Richmond | 60 min |
| May 4, 5:37 PM EDT | Severe Thunderstorm Warning | RAH | Anson, Richmond, Scotland | 53 min |
| May 4, 5:57 PM EDT | Severe Thunderstorm Warning | ILM | Robeson | 33 min |
| May 4, 6:03 PM EDT | Severe Thunderstorm Warning | CAE | Bamberg, Barnwell, Calhoun, Orangeburg, Richland | 57 min |
| May 4, 6:07 PM EDT | Severe Thunderstorm Warning | CAE | Clarendon, Lee, Richland, Sumter | 53 min |
| May 4, 6:14 PM EDT | Severe Thunderstorm Warning | RAH | Cumberland, Harnett, Hoke, Moore | 61 min |
| May 4, 6:30 PM EDT | Severe Thunderstorm Warning | ILM | Robeson | 30 min |
| May 4, 6:57 PM EDT | Severe Thunderstorm Warning | CAE | Clarendon | 48 min |
| May 4, 7:04 PM EDT | Severe Thunderstorm Warning | ILM | Florence, Williamsburg | 41 min |
| May 4, 7:42 PM EDT | Severe Thunderstorm Warning | ILM | Florence, Georgetown, Marion, Williamsburg | 33 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Charleston AFB, SC (KCHS), launched 12:00Z, 8.9 hours before the alert went out and 146 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.
- Mixed-layer CAPE
- 573 J/kg
- Mixed-layer CIN
- -149 J/kg
- Mixed-layer LCL
- 1000 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 68 m²/s²
- 0-3 km storm-relative helicity
- 48 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.0
The text
As transmitted.
830 WWUS20 KWNS 042052 SEL0 SPC WW 042052 GAZ000-NCZ000-SCZ000-050100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 150 NWS Storm Prediction Center Norman OK 455 PM EDT Tue May 4 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far east-central Georgia Southern North Carolina Central South Carolina * Effective this Tuesday afternoon and evening from 455 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Multiple clusters should continue to pose a risk for scattered damaging winds and isolated severe hail for a few more hours across a portion of the Piedmont before weakening over the coastal plain. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 20 miles southeast of Augusta GA to 25 miles east northeast of Southern Pines NC. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 144...WW 145...WW 146...WW 147...WW 148...WW 149... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 25030. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 8:31 AM EDT | Mesoscale Discussion | SPC | Dade | 89 min |
| May 4, 10:03 AM EDT | Mesoscale Discussion | SPC | Bartow, Carroll, Chattooga, Cherokee, Cobb, Douglas and 8 more | 117 min |
| May 4, 10:48 AM EDT | Severe Thunderstorm Watch | SPC | Banks, Barrow, Bartow, Butts, Carroll, Catoosa and 43 more | 6 hr |
| May 4, 1:21 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Bartow, Carroll, Cherokee, Clarke and 34 more | 114 min |
| May 4, 3:07 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Bartow, Butts, Carroll, Cherokee and 35 more | 113 min |
| May 4, 6:20 PM EDT | Mesoscale Discussion | SPC | Baker, Bibb, Calhoun, Chattahoochee, Clay, Colquitt and 34 more | 85 min |
| May 4, 7:26 PM EDT | Severe Thunderstorm Watch | SPC | Baker, Ben Hill, Berrien, Bibb, Bleckley, Brooks and 45 more | 6 hr |
| May 4, 9:37 AM EDT | Severe Thunderstorm Watch | SPC | Cherokee, Clay, Graham, Macon, Swain | 3 hr |
| May 4, 1:04 PM EDT | Mesoscale Discussion | SPC | Caswell, Northampton, Person, Rockingham, Stokes, Surry and 2 more | 56 min |
| May 4, 4:16 PM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Bladen, Cabarrus, Caswell, Chatham and 35 more | 119 min |
| May 4, 7:59 PM EDT | Mesoscale Discussion | SPC | Berkeley, Clarendon, Dorchester, Marion, Williamsburg | 61 min |
Nearby
Severe Thunderstorm Watches in South Carolina, 2021Severe Thunderstorm Watches in North Carolina, 2021Severe Thunderstorm Watches in Georgia, 2021Every severe thunderstorm 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.