Alert archive / South Carolina / Flash Flood Watches in 2018

Flash Flood Watch 1, NWS Charleston, SC

July 20, 2018Berkeley County, Dorchester County, South Carolina

NWS Charleston, SC issued this flash flood watch at Jul 20, 2018, 3:28 AM EDT for Berkeley County, Dorchester County, South Carolina. It was in force for 15 hr.

The area

The counties it named.

The facts

Issued
Jul 20, 2018, 3:28 AM EDT (07:28 UTC)
Expired
Jul 20, 2018, 6:51 PM EDT
In force
15 hr
Issued by
NWS Charleston, SC
Flood severity
None

Counties Berkeley County, SC, Dorchester County, SC

The radar

The Charleston,SC radar (KCLX), 97 km from the middle of the area, began a volume at 07:28 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, 7.5 hours before the alert went out and 31 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 00:00Z on 2018-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 844 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 00:00Z on 2018-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
844 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
820 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 3:51 AM EDTAreal Flood AdvisoryCHSCharleston54 min
Jul 20, 5:05 AM EDTAreal Flood AdvisoryCHSCharleston55 min
Jul 20, 5:44 AM EDTAreal Flood AdvisoryCHSCharleston46 min
Jul 20, 6:06 AM EDTFlash Flood WarningCHSCharleston114 min
Jul 20, 6:23 AM EDTAreal Flood AdvisoryCHSBerkeley, Charleston82 min
Jul 20, 7:14 AM EDTAreal Flood AdvisoryCHSCharleston91 min
Jul 20, 7:52 AM EDTAreal Flood AdvisoryCHSCharleston113 min
Jul 20, 7:58 AM EDTAreal Flood WarningCHSCharleston3 hr
Jul 20, 8:09 AM EDTAreal Flood AdvisoryCHSColleton, Dorchester81 min
Jul 20, 8:17 AM EDTAreal Flood AdvisoryCHSAllendale88 min
Jul 20, 8:49 AM EDTSpecial Marine WarningCHS87 min
Jul 20, 9:50 AM EDTAreal Flood AdvisoryCHSAllendale115 min
Jul 20, 10:13 AM EDTAreal Flood AdvisoryCHSCharleston2 hr
Jul 20, 11:01 AM EDTAreal Flood WarningCHSCharleston8 hr
Jul 20, 11:46 AM EDTAreal Flood AdvisoryCHSAllendale59 min
Jul 20, 4:45 PM EDTAreal Flood AdvisoryCHSBeaufort, Colleton90 min
Jul 20, 3:21 PM EDTAreal Flood AdvisoryCHSMcIntosh84 min
Jul 20, 4:57 PM EDTAreal Flood AdvisoryCHSChatham2 hr

Nearby

Flash Flood Watches in South Carolina, 2018Every flash flood watch in 2018

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.