Alert archive / South Carolina / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 85, NWS Wilmington, NC

September 21, 2017Williamsburg County, South Carolina

NWS Wilmington, NC issued this severe thunderstorm warning at Sep 21, 2017, 6:19 PM EDT for Williamsburg County, South Carolina. It was in force for 44 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: Sep 21, 2017, 6:19 PM EDT (22:19 UTC)
Expired: Sep 21, 2017, 7:03 PM EDT
In force: 44 min
Issued by: NWS Wilmington, NC
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 127 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

Charleston AFB, SC (KCHS), launched 12:00Z, 10.3 hours before the alert went out and 84 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: 1063 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 994 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 32 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 Wilmington, NC wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 21, 3:04 PM EDT, 3 hours 15 minutes earlier.

Area forecast discussion, Sep 21, 3:04 PM EDT, 3 hours 15 minutes before

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Hazardous weather outlook, Sep 21, 3:40 PM EDT, 2 hours 39 minutes before

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In the hours before

Special weather statement, Sep 21, 5:25 PM EDT, 54 minutes before

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Special weather statement, Sep 21, 5:28 PM EDT, 51 minutes before

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Special weather statement, Sep 21, 5:51 PM EDT, 28 minutes before

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Special weather statement, Sep 21, 5:54 PM EDT, 25 minutes before

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Special weather statement, Sep 21, 5:56 PM EDT, 23 minutes before

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Special weather statement, Sep 21, 6:01 PM EDT, 18 minutes before

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The office that day

Everything else NWS Wilmington, NC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 21, 3:00 PM EDT	Special Weather Statement	ILM	Horry	60 min
Sep 21, 3:44 PM EDT	Areal Flood Advisory	ILM	Horry	91 min
Sep 21, 4:14 PM EDT	Special Weather Statement	ILM	Horry	31 min
Sep 21, 4:44 PM EDT	Special Weather Statement	ILM	Horry	31 min
Sep 21, 4:50 PM EDT	Areal Flood Advisory	ILM	Horry, Marion	85 min
Sep 21, 5:13 PM EDT	Special Weather Statement	ILM	Georgetown	32 min
Sep 21, 5:42 PM EDT	Areal Flood Advisory	ILM	Georgetown	3 hr
Sep 21, 5:51 PM EDT	Special Weather Statement	ILM	Williamsburg	54 min
Sep 21, 6:41 PM EDT	Special Weather Statement	ILM	Williamsburg	64 min
Sep 21, 6:57 PM EDT	Special Weather Statement	ILM	Williamsburg	33 min
Sep 21, 7:23 PM EDT	Special Weather Statement	ILM	Dillon	37 min
Sep 20, 8:04 PM EDT	Special Weather Statement	ILM	Bladen	56 min
Sep 21, 12:00 AM EDT	Special Weather Statement	ILM	Columbus	60 min
Sep 21, 3:13 AM EDT	Coastal Flood Advisory	ILM	New Hanover	9 hr
Sep 21, 2:45 PM EDT	Coastal Flood Advisory	ILM	New Hanover	10 hr
Sep 21, 2:55 PM EDT	Severe Thunderstorm Warning	ILM	Brunswick	26 min
Sep 21, 3:20 PM EDT	Special Weather Statement	ILM	Bladen	40 min
Sep 21, 4:06 PM EDT	Special Weather Statement	ILM	Pender	54 min
Sep 21, 4:25 PM EDT	Special Weather Statement	ILM	Pender	35 min
Sep 21, 5:06 PM EDT	Areal Flood Advisory	ILM	New Hanover, Pender	84 min
Sep 21, 5:25 PM EDT	Special Weather Statement	ILM	Columbus	65 min
Sep 21, 5:28 PM EDT	Special Weather Statement	ILM	Bladen	62 min
Sep 21, 5:54 PM EDT	Special Weather Statement	ILM	Robeson	66 min
Sep 21, 5:56 PM EDT	Special Weather Statement	ILM	Columbus	64 min
Sep 21, 6:01 PM EDT	Special Weather Statement	ILM	New Hanover	29 min

Nearby

Severe Thunderstorm Warnings in South Carolina, 2017 Every severe thunderstorm warning in 2017

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.