Alert archive / South Carolina / Areal Flood Advisories in 2020

Areal Flood Advisory 21, NWS Columbia, SC

May 20, 20206 counties in South Carolina

NWS Columbia, SC issued this areal flood advisory at May 20, 2020, 1:49 PM EDT for 6 counties in South Carolina. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
May 20, 2020, 1:49 PM EDT (17:49 UTC)
Expired
May 20, 2020, 4:45 PM EDT
In force
3 hr
Issued by
NWS Columbia, SC
Area
Storm-based polygon

Counties Chesterfield County, SC, Clarendon County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Sumter County, SC

The radar

The Columbia radar (KCAE), 75 km from the middle of the area, began a volume at 17:51 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, 5.8 hours before the alert went out and 153 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 2020-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 631 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 2020-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 136 square meters per square second.19395878Sfc1 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
631 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
659 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
136 m²/s²
0-3 km storm-relative helicity
213 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.9

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
May 19, 9:50 PM EDTRiver Flood WarningCAEKershaw38 hr
May 19, 9:50 PM EDTRiver Flood WarningCAENewberry, Union4 days
May 19, 9:50 PM EDTRiver Flood WarningCAEFairfield, Kershaw, Lancaster17 days
May 19, 10:31 PM EDTAreal Flood AdvisoryCAEChesterfield, Kershaw, Lee, Sumter119 min
May 20, 6:20 AM EDTRiver Flood WarningCAELexington, Richland29 hr
May 20, 11:06 AM EDTAreal Flood AdvisoryCAECalhoun, Clarendon, Orangeburg, Richland, Sumter114 min
May 20, 11:48 AM EDTAreal Flood AdvisoryCAEClarendon, Lee, Orangeburg, Sumter117 min
May 20, 6:05 PM EDTAreal Flood AdvisoryCAELancaster115 min

Nearby

Areal Flood Advisories in South Carolina, 2020Every areal flood advisory 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.