Alert archive / South Carolina / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 274

June 15, 202118 counties in North Carolina; 20 counties in South Carolina

The Storm Prediction Center issued this severe thunderstorm watch at Jun 15, 2021, 1:58 PM EDT for 18 counties in North Carolina; 20 counties in South Carolina. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 15, 2021, 1:58 PM EDT (17:58 UTC)
Expired
Jun 15, 2021, 9:00 PM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
65 kt
All 38 counties

Beaufort County, NC, Bladen County, NC, Brunswick County, NC, Carteret County, NC, Columbus County, NC, Craven County, NC, Dare County, NC, Duplin County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, New Hanover County, NC, Onslow County, NC, Pamlico County, NC, Pender County, NC, Robeson County, NC, Tyrrell County, NC, Washington County, NC, Bamberg County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Darlington County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Lee County, SC, Lexington County, SC, Marion County, SC, Marlboro County, SC, Orangeburg County, SC, Richland County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 70 km from the middle of the area, began a volume at 18:00 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
50%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 15, 2:36 PM EDTSevere Thunderstorm WarningMHXDuplin, Jones, Lenoir, Onslow24 min
Jun 15, 2:54 PM EDTSevere Thunderstorm WarningMHXCarteret, Craven, Jones, Onslow51 min
Jun 15, 3:12 PM EDTSevere Thunderstorm WarningILMFlorence, Horry, Marion48 min
Jun 15, 3:30 PM EDTSevere Thunderstorm WarningMHXCarteret, Craven, Jones, Onslow, Pamlico30 min
Jun 15, 3:34 PM EDTSevere Thunderstorm WarningILMNew Hanover, Pender26 min
Jun 15, 3:54 PM EDTSevere Thunderstorm WarningILMHorry36 min
Jun 15, 4:12 PM EDTSevere Thunderstorm WarningILMBrunswick, Columbus63 min
Jun 15, 4:37 PM EDTSevere Thunderstorm WarningCHSBerkeley, Dorchester38 min
Jun 15, 5:59 PM EDTSevere Thunderstorm WarningCAECalhoun, Clarendon, Orangeburg31 min
Jun 15, 6:27 PM EDTSevere Thunderstorm WarningCAECalhoun, Clarendon, Orangeburg48 min
Jun 15, 7:00 PM EDTSevere Thunderstorm WarningCHSBerkeley45 min
Jun 15, 7:46 PM EDTSevere Thunderstorm WarningCHSBerkeley, Charleston59 min
Jun 15, 8:02 PM EDTSevere Thunderstorm WarningCHSCharleston, Colleton37 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

Newport, NC (KMHX), launched 12:00Z, 6.0 hours before the alert went out and 97 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, Newport, NC at 12:00Z on 2021-06-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1287 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, Newport, NC at 12:00Z on 2021-06-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 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
1287 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
947 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

Open this sounding in Storm Lab

The text

As transmitted.

009 
WWUS20 KWNS 151755
SEL4  
SPC WW 151755
NCZ000-SCZ000-CWZ000-152300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 274
NWS Storm Prediction Center Norman OK
200 PM EDT Tue Jun 15 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Southern to eastern North Carolina
  Central to eastern South Carolina
  Coastal Waters

* Effective this Tuesday afternoon and evening from 200 PM until
  700 PM EDT.

* Primary threats include...
  Scattered damaging winds and isolated significant gusts to 75
    mph possible
  Isolated very large hail events to 2 inches in diameter possible

SUMMARY...Multiple supercells may consolidate into one or more
clusters towards the Carolina Coast this afternoon.

The severe thunderstorm watch area is approximately along and 55
statute miles north and south of a line from 5 miles north northeast
of Cape Hatteras NC to 20 miles southwest of Orangeburg SC. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).

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.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
29030.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 15, 12:57 PM EDTMesoscale DiscussionSPCAnson, Beaufort, Bertie, Bladen, Brunswick, Carteret and 30 more63 min
Jun 15, 4:09 PM EDTMesoscale DiscussionSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 10 more96 min

Nearby

Severe Thunderstorm Watches in South Carolina, 2021Severe Thunderstorm Watches in North Carolina, 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.