Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 23, NWS New Orleans, LA

May 5, 2021Saint Charles Parish, Saint James Parish, Saint John the Baptist Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at May 5, 2021, 7:20 AM CDT for Saint Charles Parish, Saint James Parish, Saint John the Baptist Parish, Louisiana. It was in force for 115 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 5, 2021, 7:20 AM CDT (12:20 UTC)
Expired
May 5, 2021, 9:15 AM CDT
In force
115 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 0.3 hours before the alert went out and 79 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, Slidell Radar S, LA at 12:00Z on 2021-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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, Slidell Radar S, LA at 12:00Z on 2021-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 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
6 J/kg
Mixed-layer CIN
-305 J/kg
Mixed-layer LCL
750 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.2

Open this sounding in Storm Lab

The text

As transmitted.

485 
WGUS54 KLIX 051220
FFWLIX
LAC089-093-095-051415-
/O.NEW.KLIX.FF.W.0023.210505T1220Z-210505T1415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
720 AM CDT Wed May 5 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Northwestern St. Charles Parish in southeastern Louisiana...
  East Central St. James Parish in southeastern Louisiana...
  West Central St. John The Baptist Parish in southeastern Louisiana...

* Until 915 AM CDT.

* At 720 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Reserve, Laplace, Gramercy, Lutcher, Edgard, Killona, Garyville, 
  Wallace, Montz, Taft, North Vacherie and Norco.

This includes the following Interstates...
	Interstate 55 in Louisiana between mile markers 1 and 2.
	Interstate 10 in Louisiana between mile markers 206 and 211...and
	between mile markers 215 and 220.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

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.

&&

LAT...LON 2996 9080 3004 9082 3012 9043 3008 9041
      3006 9038 3005 9033 3006 9031 3005 9028
      3001 9028

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1.5-2 INCHES IN 2 HOURS 

$$

TE

The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 7:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 8:03 PM CDTSpecial Weather StatementLIXTangipahoa27 min
May 4, 8:13 PM CDTSpecial Weather StatementLIXWashington17 min
May 4, 8:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 9:06 PM CDTRiver Flood WarningLIXSaint Tammany69 hr
May 4, 10:03 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint John the Baptist, Tangipahoa27 min
May 4, 10:06 PM CDTSpecial Marine WarningLIX24 min
May 4, 10:25 PM CDTSpecial Marine WarningLIX65 min
May 4, 10:28 PM CDTSevere Thunderstorm WarningLIXSaint John the Baptist, Tangipahoa5 min
May 5, 12:47 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Saint Bernard, Saint Charles, Saint James, Saint John the Baptist103 min
May 5, 1:15 AM CDTSpecial Weather StatementLIXOrleans45 min
May 5, 4:24 AM CDTAreal Flood AdvisoryLIXSaint Tammany3 hr
May 5, 6:16 AM CDTRiver Flood WarningLIXSaint Tammany25 hr
May 5, 6:45 AM CDTAreal Flood AdvisoryLIXSaint Charles, Saint James, Saint John the Baptist2 hr
May 5, 7:01 AM CDTFlash Flood WarningLIXSaint Tammany89 min
May 5, 7:39 AM CDTSpecial Marine WarningLIX36 min
May 5, 7:48 AM CDTAreal Flood AdvisoryLIXOrleans, Saint Tammany117 min
May 5, 8:00 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles2 hr
May 5, 8:25 AM CDTFlash Flood WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard2 hr
May 5, 9:23 AM CDTSpecial Marine WarningLIX67 min
May 5, 10:25 AM CDTSpecial Marine WarningLIX50 min
May 5, 10:31 AM CDTSpecial Marine WarningLIX59 min
May 5, 11:11 AM CDTSpecial Marine WarningLIX49 min

Nearby

Flash Flood Warnings in Louisiana, 2021Every flash flood warning in 2021

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.