Alert archive / South Carolina / Flash Flood Warnings in 2017

Flash Flood Warning 19, NWS Columbia, SC

September 12, 2017Richland County, South Carolina

NWS Columbia, SC issued this flash flood warning at Sep 12, 2017, 2:45 AM EDT for Richland County, South Carolina. It was in force for 90 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 12, 2017, 2:45 AM EDT (06:45 UTC)
Expired: Sep 12, 2017, 4:15 AM EDT
In force: 90 min
Issued by: NWS Columbia, SC
Area: Storm-based polygon
Flood severity: None

County Richland County, SC

The radar

The Columbia radar (KCAE), 21 km from the middle of the area, began a volume at 06:43 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 00:00Z, 6.8 hours before the alert went out and 150 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: 458 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 652 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 334 m²/s²
0-3 km storm-relative helicity: 383 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 6.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Sep 11, 5:19 PM EDT, 9 hours 26 minutes earlier.

Area forecast discussion, Sep 11, 5:19 PM EDT, 9 hours 26 minutes before

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Hazardous weather outlook, Sep 11, 7:10 PM EDT, 7 hours 35 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 11, 8:09 PM EDT	Areal Flood Advisory	CAE	Calhoun, Lexington, Richland, Sumter	3 hr
Sep 11, 8:54 PM EDT	Lake Wind Advisory	CAE	Aiken, Bamberg, Barnwell, Calhoun, Chesterfield, Clarendon and 10 more	5 hr
Sep 11, 11:29 PM EDT	Areal Flood Advisory	CAE	Aiken, Lexington, Saluda	2 hr

Nearby

Flash Flood Warnings in South Carolina, 2017 Every flash flood 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.