Alert archive / South Carolina / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 153, NWS Columbia, SC

August 13, 2020Sumter County, South Carolina

NWS Columbia, SC issued this severe thunderstorm warning at Aug 13, 2020, 3:50 PM EDT for Sumter County, South Carolina. It was in force for 40 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 13, 2020, 3:50 PM EDT (19:50 UTC)
Expired
Aug 13, 2020, 4:30 PM EDT
In force
40 min
Issued by
NWS Columbia, SC
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Sumter County, SC

The radar

The Columbia radar (KCAE), 68 km from the middle of the area, began a volume at 19:54 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

Charleston AFB, SC (KCHS), launched 12:00Z, 7.8 hours before the alert went out and 118 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, Charleston AFB, SC at 12:00Z on 2020-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1290 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, Charleston AFB, SC at 12:00Z on 2020-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -35 square meters per square second.1939Sfc1 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
1290 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
815 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-35 m²/s²
0-3 km storm-relative helicity
-17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 13, 2:40 PM EDT, 1 hour 10 minutes earlier.

Area forecast discussion, Aug 13, 2:40 PM EDT, 1 hour 10 minutes before
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Hazardous weather outlook, Aug 13, 4:22 AM EDT, 11 hours 28 minutes before
Hazardous Weather Outlook
National Weather Service Columbia SC
422 AM EDT Thu Aug 13 2020

GAZ040-063>065-077-SCZ016-018-020>022-025>031-035>038-041-115-116-
140830-
Lincoln-McDuffie-Columbia-Richmond-Burke-Chesterfield-McCormick-
Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-Richland-Lee-
Aiken-Sumter-Barnwell-Orangeburg-Calhoun-Clarendon-Bamberg-
Northern Lancaster-Southern Lancaster-
422 AM EDT Thu Aug 13 2020

This Hazardous Weather Outlook is for the Midlands of South Carolina
and the Central Savannah River area of Georgia.

.DAY ONE...Today and tonight.

Scattered slow-moving thunderstorms producing heavy rain may lead to
localized flooding today.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Special weather statement, Aug 13, 1:17 PM EDT, 2 hours 33 minutes before
Special Weather Statement
National Weather Service Columbia SC
117 PM EDT Thu Aug 13 2020

SCZ016-022-116-131745-
Chesterfield SC-Southern Lancaster SC-Kershaw SC-
117 PM EDT Thu Aug 13 2020

...Strong Thunderstorms Will Impact Portions of west central
Chesterfield...Southern Lancaster and northeastern Kershaw Counties
Until 145 PM EDT....

At 117 PM EDT...National Weather Service doppler radar indicated a
strong thunderstorm near Kershaw, or 17 miles northeast of Lake
Wateree Dam, moving southwest at 10 mph.

  HAZARD...gusty winds 40 to 50 mph, pea sized hail, excessive cloud
           to ground lightning and localized minor flooding.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely. All outdoor activities should cease. Move
           indoors immediately. Localized, minor flooding of low
           lying and poor drainage areas is also possible.

Some locations in the path of this storm include...
Kershaw, Elgin, Heath Springs, Mt Pisgah, Jefferson, Pleasant Hill,
Kershaw Correctional Institution, North Central High School, Bear
Creek Park, Kirk Air Base, Forty Acre Rock Preserve and McDonald
Green Elementary School.

Heavy rainfall is occurring with this storm, and may cause localized
flooding. Do not drive your vehicle through flooded roadways.

Move indoors immediately.  Excessive cloud to ground lightning is
occurring with this storm. If you can hear thunder, you are close
enough to be struck by lightning.

LAT...LON 3470 8064 3466 8029 3451 8030 3439 8051
      3465 8082
TIME...MOT...LOC 1717Z 067DEG 10KT 3455 8053

LCV
Special weather statement, Aug 13, 2:57 PM EDT, 53 minutes before
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Special weather statement, Aug 13, 3:06 PM EDT, 44 minutes before
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Local storm report, Aug 13, 3:11 PM EDT, 39 minutes before
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Special weather statement, Aug 13, 3:46 PM EDT, 4 minutes before
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Special weather statement, Aug 13, 3:47 PM EDT, 3 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 1:17 PM EDTSpecial Weather StatementCAELancaster28 min
Aug 13, 1:20 PM EDTSevere Thunderstorm WarningCAEChesterfield, Kershaw, Lancaster40 min
Aug 13, 2:57 PM EDTSpecial Weather StatementCAECalhoun48 min
Aug 13, 3:06 PM EDTSpecial Weather StatementCAECalhoun39 min
Aug 13, 3:46 PM EDTSpecial Weather StatementCAESumter29 min
Aug 13, 3:47 PM EDTSpecial Weather StatementCAEClarendon43 min
Aug 13, 4:03 PM EDTSpecial Weather StatementCAECalhoun27 min
Aug 13, 4:43 PM EDTSpecial Weather StatementCAEBamberg32 min
Aug 13, 6:06 PM EDTAreal Flood AdvisoryCAEBamberg, Barnwell114 min

Nearby

Severe Thunderstorm Warnings in South Carolina, 2020Every severe thunderstorm warning in 2020

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.