Alert archive / South Carolina / Flash Flood Warnings in 2017

Flash Flood Warning 3, NWS Charleston, SC

May 23, 2017Charleston County, South Carolina

NWS Charleston, SC issued this flash flood warning at May 23, 2017, 5:23 PM EDT for Charleston County, South Carolina. It was in force for 6 hr. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 23, 2017, 5:23 PM EDT (21:23 UTC)
Expired
May 23, 2017, 11:15 PM EDT
In force
6 hr
Issued by
NWS Charleston, SC
Area
Storm-based polygon
Flood severity
None

County Charleston County, SC

The radar

The Charleston,SC radar (KCLX), 104 km from the middle of the area, began a volume at 21:23 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.

What was reported inside it

TimeReportWhereRemark
May 23, 5:57 PM EDTHEAVY RAIN 0Charleston, SCSEVERAL ROADS IN DOWNTOWN CHARLESTON ARE FLOODED... INCLUDING EAST BAY AND PRESIDENTS STREET.
May 23, 7:40 PM EDTHEAVY RAIN 01 S West Ashley, SCWEST ROBINHOOD DRIVE WAS CLOSED DUE TO FLOODING.
May 23, 7:40 PM EDTHEAVY RAIN 0Charleston, SCLAW ENFORCEMENT REPORTS AROUND A DOZEN ROADS CLOSED DUE TO FLOODING ACROSS THE CITY OF CHARLESTON.
May 23, 7:40 PM EDTHEAVY RAIN 0Charleston, SCSOCIAL MEDIA PICTURE SHOWS WATER AROUND TWO FEET DEEP ACROSS CANNON PARK.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 9.4 hours before the alert went out and 11 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 2017-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 403 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Charleston AFB, SC at 12:00Z on 2017-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 square meters per square second.193958Sfc1 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
403 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
774 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

717 
WGUS52 KCHS 232123
FFWCHS
SCC019-240315-
/O.NEW.KCHS.FF.W.0003.170523T2123Z-170524T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Charleston SC
523 PM EDT TUE MAY 23 2017

The National Weather Service in Charleston has issued a

* Flash Flood Warning for portions of...
  Charleston County in southeastern South Carolina...

* Until 1115 PM EDT

* At 520 PM EDT, radar rainfall estimates indicate that 1.5 to 2.5 
  inches of rain has fallen across Charleston and surrounding areas 
  since 2 PM. The previous heavy rainfall resulted in multiple 
  flooded roads and a couple of water rescues. Based on latest 
  reports, several roads remain closed due to lingering flood 
  waters. Through 7 PM, showers and thunderstorms will result in 
  rounds of moderate rainfall. In addition, a cluster of strong to 
  severe storms is expected to move across the Charleston peninsula 
  during the early to mid evening hours. These storms will likely 
  provide torrential rainfall rates. The arrival of the heavy 
  downpours will overlap with this evenings high tide, resulting in 
  significant street flooding and building flooding. Many roads will 
  be impassable.

* Some locations that will experience flooding include...
  Charleston, North Charleston, Mount Pleasant, Downtown Charleston,
  and West Ashley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

High tide will inhibit runoff of heavy rain, flooding areas of poor
drainage in Downtown Charleston. Areas most prone to flooding include
the Market, Crosstown, East Bay Street and Morrison Drive.

Report flooding directly to the Charleston National Weather Service
at 1-888-383-2024 or email your reports to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3278 7984 3275 8002 3285 8006 3285 8004
      3286 7996 3282 7993 3282 7987

$$

NED
3 follow-up statements
973 
WGUS72 KCHS 232242
FFSCHS

Flash Flood Statement
National Weather Service Charleston SC
642 PM EDT TUE MAY 23 2017

SCC019-240315-
/O.CON.KCHS.FF.W.0003.000000T0000Z-170524T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Charleston SC-
642 PM EDT TUE MAY 23 2017

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT FOR
PORTIONS OF CHARLESTON COUNTY...

At 641 PM EDT, local law enforcement and Charleston County officials 
reported numerous roads flooded across the city of Charleston. Up to 
three inches of rain have already fallen across the Charleston 
peninsula and surrounding areas. At 640 PM, Doppler radar indicated 
clusters of strong thunderstorms upstream of the Charleston area. 
These storms are expected to track across the warned area, producing 
torrential downpours. In addition, high tide will peak at 645 PM, 
with tide water remaining high through 730 PM. Flood waters will 
deepen over flooded streets, with some areas seeing flood waters a 
few feet deep. Many roads will be impassible with flooding of 
some homes and businesses likely through 9 PM.

Some locations that will experience flooding include...
Charleston, North Charleston, Mount Pleasant, Downtown Charleston,
West Ashley, and Charles Towne Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

High tide will inhibit runoff of heavy rain, flooding areas of poor
drainage in Downtown Charleston. Areas most prone to flooding include
the Market, Crosstown, East Bay Street and Morrison Drive.

Report flooding directly to the Charleston National Weather Service
at 1-888-383-2024 or email your reports to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3278 7984 3275 8002 3285 8006 3285 8004
      3286 7996 3282 7993 3282 7987

$$

NED
376 
WGUS72 KCHS 240022
FFSCHS

Flash Flood Statement
National Weather Service Charleston SC
822 PM EDT TUE MAY 23 2017

SCC019-240315-
/O.CON.KCHS.FF.W.0003.000000T0000Z-170524T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Charleston SC-
822 PM EDT TUE MAY 23 2017

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT FOR
PORTIONS OF CHARLESTON COUNTY...

At 821 PM EDT, radar rainfall estimates and automated rain gauges 
indicated that between 2.5 to 4.5 inches of rain has fallen across 
the Charleston peninsula and surrounding areas since early this 
afternoon. Law enforcement and social media posts indicate that 
numerous roads remain closed due to flooding. By 930 PM, additional 
showers and thunderstorms are expected to pass over the warned area. 
Rainfall rates may range between half to one inch an hour. The 
additional rainfall should worsen ongoing flooding and may result in 
more flooded areas.

Some locations that will experience flooding 
include... Charleston, North Charleston, Mount Pleasant, Downtown 
Charleston, West Ashley, and Charles Towne Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Report flooding directly to the Charleston National Weather Service
at 1-888-383-2024 or email your reports to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3278 7984 3275 8002 3285 8006 3285 8004
      3286 7996 3282 7993 3282 7987

$$

NED
233 
WGUS72 KCHS 240312
FFSCHS

Flash Flood Statement
National Weather Service Charleston SC
1112 PM EDT TUE MAY 23 2017

SCC019-240321-
/O.EXP.KCHS.FF.W.0003.000000T0000Z-170524T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Charleston SC-
1112 PM EDT TUE MAY 23 2017

...THE FLASH FLOOD WARNING FOR CHARLESTON COUNTY WILL EXPIRE AT 1115
PM EDT...

The heavy rain has ended. Flooding is no longer expected to pose a
serious threat. Please continue to heed any remaining road closures.

LAT...LON 3278 7984 3275 8002 3285 8006 3285 8004
      3286 7996 3282 7993 3282 7987

$$

MTE

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 3:34 AM EDTFlash Flood WatchCHSAllendale, Berkeley, Colleton, Dorchester, Hampton20 hr
May 23, 3:35 AM EDTSmall Craft AdvisoryCHS70 hr
May 23, 1:28 PM EDTAreal Flood AdvisoryCHSBerkeley, Charleston92 min
May 23, 2:48 PM EDTAreal Flood AdvisoryCHSCharleston57 min
May 23, 3:48 PM EDTSpecial Marine WarningCHS57 min
May 23, 4:38 PM EDTAreal Flood AdvisoryCHSBerkeley, Charleston, Colleton52 min
May 23, 5:29 PM EDTSpecial Marine WarningCHS61 min
May 23, 5:56 PM EDTSpecial Marine WarningCHS94 min
May 23, 6:15 PM EDTSpecial Weather StatementCHSBeaufort30 min
May 23, 6:32 PM EDTSpecial Marine WarningCHS88 min
May 23, 6:42 PM EDTSpecial Marine WarningCHS2 hr
May 23, 6:47 PM EDTTornado WarningCHSCharleston, Colleton28 min
May 23, 7:15 PM EDTSevere Thunderstorm WarningCHSCharleston25 min
May 23, 7:28 PM EDTSpecial Marine WarningCHS47 min

Nearby

Flash Flood Warnings in South Carolina, 2017Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.