Alert archive / South Carolina / Flash Flood Warnings in 1999

Flash Flood Warning 1, NWS Charleston, SC

May 12, 1999Beaufort County, Charleston County, Colleton County, South Carolina

NWS Charleston, SC issued this flash flood warning at May 12, 1999, 3:05 PM EDT for Beaufort County, Charleston County, Colleton County, South Carolina. It was in force for 75 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: May 12, 1999, 3:05 PM EDT (19:05 UTC)
Expired: May 12, 1999, 4:20 PM EDT
In force: 75 min
Issued by: NWS Charleston, SC
Area: Whole counties

Counties Beaufort County, SC, Charleston County, SC, Colleton County, SC

The radar

The Charleston,SC radar (KCLX), 58 km from the middle of the area, began a volume at 19:04 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, 7.1 hours before the alert went out and 49 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: 335 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 501 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 103 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KCHS 121910 COR
FFWCHS
SCC013-015-019-029-122020-

FLOOD WARNING - CORRECTED SECOND PARAGRAPH
NATIONAL WEATHER SERVICE CHARLESTON SC
305 PM EDT WED MAY 12 1999

THE NATIONAL WEATHER SERVICE IN CHARLESTON HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN THE FOLLOWING
  COUNTIES...
  BEAUFORT COUNTY IN SOUTH CAROLINA,
  SOUTHERN BERKELEY COUNTY IN SOUTH CAROLINA,
  CHARLESTON COUNTY IN SOUTH CAROLINA,
  SOUTHERN COLLETON COUNTY IN SOUTH CAROLINA,

* UNTIL 420 PM EDT.

* AT 300 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF THUNDERSTORMS WITH VERY HEAVY RAIN ALONG THE COAST...MOVING
  LITTLE.
* A LINE OF THUNDERSTORMS STALLED ALONG THE SEA BREEZE FRONT WILL
  BRING PROLONGED PERIODS OF HEAVY RAINFALL TO AREAS STRETCHING
  FROM MCCELLANVILLE TO BEAUFORT. ADDITIONAL RAINFALL AMOUNTS OF 3
  TO 4 INCHES IS POSSIBLE THROUGH 4 PM.

DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD!

JCI

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 Charleston, SC wrote its last area forecast discussion before this flash flood warning went out at May 12, 2:38 PM EDT, 27 minutes earlier.

Area forecast discussion, May 12, 2:38 PM EDT, 27 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
238 PM EDT WED MAY 12 1999

BOTH SFC HI OVR HUDSON BAY AND BERMUDA HI ARE LOCKED INTO
PLACE AND PREVENTING SFC LOW ALONG COAST FROM EXITING. AVN HAS
HAD IMPRESSIVE HANDLE ON THIS CSTL LOW FOR LAST FEW DAYS WITH NGM
AND ETA DISAPPOINTNG...SO WILL LEAN HEAVILY ON THE AVN FCST. APRCHNG
SFC L OVR SE MO ATTM TRIES TO MV UP OH VALLEY BUT STRONG HI TO THE N
RAMS IT BACK TO SC BY FRI TO MERGE WITH REMENANTS OF PRESENT CSTL LO.
RESULTING LO DRIFTS OFFSHORE OF JAX BY SAT. SO THRU SAT...UNSETTLED
WX...WIND SPEEDS LIGHT TO 15 KTS OUTSIDE OF TSTMS...WINDS CHANGING
DIR DRASTICALLY OVER PERIOD...AND SCT SHOWERS AND OCCASIONAL TSTMS.
HEAVIEST PRECIP AND STRONGEST WINDS WILL REMAIN OVR NC AND VA WHERE
SFC PRESS GRAD TIGHTEST AND DYNAMICS STRONGEST.

CWF...WILL CONTINUE IDEA OF PREVIOUS FORECAST WITH WINDS BECOMING SW
TONIGHT. PLAN TO MAKE LAST MINUTE ADJUSTMENTS TO INITIAL CONDITONS
JUST BEFORE ISSUANCE TO ACCOUNT FOR LATEST DATA AND WIND DIRECTION
CHANGES DUE TO CLOSE PROXIMITY OF THE SFC LOW. WILL CONTINUE SW ON
THU THEN SHIFT WINDS TO W ON THU NIGHT AS THE FRONT SLIPS DOWN THE
COAST. WILL DECREASE WINDS FRI AND SHIFT THEM BACK TO SW AS SECOND
LOW PRES SYSTEM MOVES OVER THE COASTAL WATERS. EXPECT SEAS TO REACH A
MAX OF 5 FT AND WINDS TO MAX OUT AROUND 15 TO 20 KT. NO MENTION OF A
SMALL CRAFT ADVISORY PLANNED AT THIS TIME.

PRELIMINARY CCF
CHS EE 063/081 063/078 063 2333233
CHL EE 067/074 067/074 067 2333233
NBC EE 061/082 061/080 061 2333233
SAV EE 063/083 063/080 063 2332222

.CHS...
SC...NONE.
GA...NONE.

SLB/SLF

The office that day

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

Issued	Product	Office	Counties	Lasted
May 12, 3:05 PM EDT	Flash Flood Warning	CHS	Berkeley	75 min

Nearby

Flash Flood Warnings in South Carolina, 1999 Every flash flood warning in 1999

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.