Alert archive / South Carolina / Severe Thunderstorm Watches in 2000

Severe Thunderstorm Watch 700

August 18, 200021 counties in South Carolina

The Storm Prediction Center issued this severe thunderstorm watch at Aug 18, 2000, 7:15 PM EDT for 21 counties in South Carolina. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 18, 2000, 7:15 PM EDT (23:15 UTC)
Expired: Aug 19, 2000, 12:00 AM EDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 21 counties

Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort 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, Hampton County, SC, Horry County, SC, Jasper County, SC, Marion County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 92 km from the middle of the area, began a volume at 23:15 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.

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Aug 18, 7:49 PM EDT	Tornado Warning	ILM	Darlington	26 min
Aug 18, 8:05 PM EDT	Severe Thunderstorm Warning	ILM	Florence, Marion	55 min
Aug 18, 8:29 PM EDT	Severe Thunderstorm Warning	CAE	Clarendon, Sumter	46 min
Aug 18, 9:15 PM EDT	Severe Thunderstorm Warning	CAE	Clarendon	45 min
Aug 18, 10:43 PM EDT	Severe Thunderstorm Warning	CHS	Berkeley	32 min
Aug 18, 11:59 PM EDT	Severe Thunderstorm Warning	CHS	Berkeley, Dorchester	31 min

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 11.3 hours before the alert went out and 55 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2682 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 792 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 61 m²/s²
0-3 km storm-relative helicity: 140 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

085 
WWUS9 KMKC 182250
SEL0  
MKC WW 182244
SCZ000-CWZ000-190400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 700
STORM PREDICTION CENTER NORMAN OK
644 PM EDT FRI AUG 18 2000

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   EASTERN SOUTH CAROLINA                     
   COASTAL WATERS                     

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 715 PM UNTIL
MIDNIGHT EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 50 STATUTE MILES
EITHER SIDE OF A LINE FROM 75 MILES WEST SOUTHWEST OF CHARLESTON
SOUTH CAROLINA TO 25 MILES NORTH NORTHWEST OF MYRTLE BEACH SOUTH
CAROLINA.

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.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 696.  WATCH NUMBER 696 WILL NOT BE
IN EFFECT AFTER 715 PM EDT.  CONTINUE...WW 697...WW 698...WW 699...

DISCUSSION...VERY UNSTABLE AIRMASS WITH CAPES NEAR 6000 J/KG ACROSS
ERN SC E OF SEA BREEZE FRONT WHICH HAS MOVED INLAND TO E OF CAE.
OUTFLOW FRONT FROM STORMS IN WRN SC MOVING 30025 WILL INTERSECT SEA
BREEZE BOUNDARY SHORTLY INITIATING RAPID DEVELOPMENT OF SEVERE
THUNDERSTORMS.  STORMS WILL THEN SPREAD E/SE TO COAST LATER THIS
EVENING.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600.  MEAN STORM
MOTION VECTOR 29030.


...HALES

332,0783 315,0804 330,0814 343,0793

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 2:00 PM EDT	Severe Thunderstorm Watch	SPC	Abbeville, Aiken, Anderson, Cherokee, Chester, Chesterfield and 22 more	6 hr

Nearby

Severe Thunderstorm Watches in South Carolina, 2000 Every severe thunderstorm watch in 2000

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.