Alert archive / South Carolina / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 118, NWS Columbia, SC

August 20, 1999McCormick County, South Carolina; Lincoln County, Georgia

NWS Columbia, SC issued this severe thunderstorm warning at Aug 20, 1999, 6:15 PM EDT for McCormick County, South Carolina; Lincoln County, Georgia. It was in force for 60 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 20, 1999, 6:15 PM EDT (22:15 UTC)
Expired: Aug 20, 1999, 7:15 PM EDT
In force: 60 min
Issued by: NWS Columbia, SC
Area: Whole counties

Counties Lincoln County, GA, McCormick County, SC

The radar

The Greer radar (KGSP), 116 km from the middle of the area, began a volume at 22:18 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.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 10.3 hours before the alert went out and 203 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: 1278 J/kg
Mixed-layer CIN: -137 J/kg
Mixed-layer LCL: 1226 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Columbia, SC wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 2:48 PM EDT, 3 hours 27 minutes earlier.

Area forecast discussion, Aug 20, 2:48 PM EDT, 3 hours 27 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
248 PM EDT FRI AUG 20 1999

FORECAST PROBLEM IS MOVEMENT OF SURFACE FRONT AND ASSOCIATED THREAT OF
CONVECTION. ETA KEEPS FRONT BACK TOWARD THE UPSTATE THROUGH 48 HOURS.
AVN AND NGM A BIT FASTER IN PUSHING THE FRONT ON EAST DURING SATURDAY.
UPPER AIR PATTERN SIMILAR WITH ONE SHORT WAVE CROSSING THE STATE THIS
EVENING AND EARLY TONIGHT. UPPER TROFFINESS CONTINUES OVER THE EAST WITH
A WEAK SHORT WAVE CROSSING SATURDAY AFTERNOON WITH MAIN ENERGY STAYING
NORTH.
PLAN TO KEEP A CHANCE OF TSTMS IN THE FORECAST TONIGHT..THEN A SLIGHT
CHANCE FROM CAE AND AGS ON EAST FOR SATURDAY. FORECAST DRY SATURDAY
NIGHT THROUGH THE EXTENDED PD.
GUIDANCE TEMPS LOOK OKAY WITH LOWS IN THE MID/UPPER 60S AND HIGHS IN THE
UPPER 80S/LOW 90S.

CAE   69/92/68/92   30/20/10
AGS   67/93/66/92   30/20/10

.CAE...NONE.

MORRISON

The office that day

Everything else NWS Columbia, SC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 19, 9:01 PM EDT	Severe Thunderstorm Warning	CAE	Richland	29 min
Aug 19, 10:12 PM EDT	Severe Thunderstorm Warning	CAE	Bamberg	33 min
Aug 19, 10:17 PM EDT	Severe Thunderstorm Warning	CAE	Orangeburg	43 min
Aug 19, 10:38 PM EDT	Tornado Warning	CAE	Bamberg	37 min
Aug 19, 11:42 PM EDT	Tornado Warning	CAE	Barnwell	33 min
Aug 20, 7:16 PM EDT	Severe Thunderstorm Warning	CAE	Newberry	29 min
Aug 20, 7:38 PM EDT	Tornado Warning	CAE	Newberry	37 min
Aug 20, 7:55 PM EDT	Severe Thunderstorm Warning	CAE	Lexington, Richland	50 min
Aug 20, 12:52 AM EDT	Severe Thunderstorm Warning	CAE	Burke	53 min
Aug 20, 2:53 AM EDT	Severe Thunderstorm Warning	CAE	Burke	52 min
Aug 20, 5:40 PM EDT	Severe Thunderstorm Warning	CAE	Burke	35 min

Nearby

Severe Thunderstorm Warnings in South Carolina, 1999 Severe Thunderstorm Warnings in Georgia, 1999 Every severe thunderstorm warning in 1999

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.