Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 13, NWS New Orleans, LA

April 10, 2021Jefferson Parish, Plaquemines Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Apr 10, 2021, 6:33 AM CDT for Jefferson Parish, Plaquemines Parish, Louisiana. It was in force for 105 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
Apr 10, 2021, 6:33 AM CDT (11:33 UTC)
Expired
Apr 10, 2021, 8:18 AM CDT
In force
105 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Jefferson Parish, LA, Plaquemines Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 11.6 hours before the alert went out and 54 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 00:00Z on 2021-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2977 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 00:00Z on 2021-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 243 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
2977 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
599 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
243 m²/s²
0-3 km storm-relative helicity
269 m²/s²
Significant tornado parameter
3.4
Supercell composite
18.1

Open this sounding in Storm Lab

The text

As transmitted.

506 
WGUS54 KLIX 101133
FFWLIX
LAC051-075-101445-
/O.NEW.KLIX.FF.W.0013.210410T1133Z-210410T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
633 AM CDT Sat Apr 10 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Northwestern Jefferson Parish in southeastern Louisiana...
  Northwestern Plaquemines Parish in southeastern Louisiana...

* Until 945 AM CDT.

* At 633 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 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...
  New Orleans, Timberlane, Belle Chasse, Harvey, Marrero, Avondale, 
  Gretna, Westwego, Jean Lafitte, Woodmere, Estelle, Terrytown, 
  Bridge City, Poydras and Waggaman.

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.

&&

LAT...LON 2991 9022 2993 9014 2991 9013 2991 9010
      2992 9007 2994 9005 2989 9000 2990 9000
      2989 8999 2990 8999 2989 8993 2987 8991
      2980 8987 2979 8986 2977 8985 2977 9019
      2982 9017 2985 9023

FLASH FLOOD...RADAR INDICATED

$$

MW
1 follow-up statement
015 
WGUS74 KLIX 101318
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
818 AM CDT Sat Apr 10 2021

LAC051-075-101328-
/O.CAN.KLIX.FF.W.0013.000000T0000Z-210410T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-Plaquemines LA-
818 AM CDT Sat Apr 10 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN JEFFERSON AND 
NORTHWESTERN PLAQUEMINES PARISHES...

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

LAT...LON 2991 9022 2993 9014 2991 9013 2991 9010
      2992 9007 2994 9005 2989 9000 2990 9000
      2989 8999 2990 8999 2989 8993 2987 8991
      2980 8987 2979 8986 2977 8985 2977 9019
      2982 9017 2985 9023

$$

MW

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 12:41 AM CDTSevere Thunderstorm WarningLIXSaint Tammany, Washington11 min
Apr 10, 1:07 AM CDTSpecial Marine WarningLIX22 min
Apr 10, 1:40 AM CDTSpecial Marine WarningLIX20 min
Apr 10, 1:45 AM CDTTornado WarningLIXPointe Coupee, West Feliciana45 min
Apr 10, 1:52 AM CDTSpecial Weather StatementLIXSaint Tammany38 min
Apr 10, 2:01 AM CDTSevere Thunderstorm WarningLIXSaint Tammany, Washington29 min
Apr 10, 2:05 AM CDTTornado WarningLIXSaint Tammany10 min
Apr 10, 2:28 AM CDTSevere Thunderstorm WarningLIXPointe Coupee, West Feliciana47 min
Apr 10, 2:48 AM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Saint Helena, West Feliciana39 min
Apr 10, 2:58 AM CDTSevere Thunderstorm WarningLIXSaint Helena, Tangipahoa35 min
Apr 10, 3:20 AM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Pointe Coupee, West Baton Rouge, West Feliciana33 min
Apr 10, 3:25 AM CDTSpecial Weather StatementLIXSaint Helena, Tangipahoa65 min
Apr 10, 3:26 AM CDTSpecial Weather StatementLIXAscension, Assumption, Livingston, Saint James, Saint John the Baptist64 min
Apr 10, 3:38 AM CDTSpecial Marine WarningLIX67 min
Apr 10, 3:59 AM CDTSpecial Weather StatementLIXEast Baton Rouge46 min
Apr 10, 4:16 AM CDTSpecial Marine WarningLIX59 min
Apr 10, 4:23 AM CDTTornado WarningLIXSaint James, Saint John the Baptist19 min
Apr 10, 4:40 AM CDTFlash Flood WarningLIXSaint Tammany, Tangipahoa, Washington3 hr
Apr 10, 4:47 AM CDTSpecial Weather StatementLIXAscension, Assumption, Orleans, Saint Charles, Saint James, Saint John the Baptist and 1 more58 min
Apr 10, 4:58 AM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles, Saint Tammany47 min
Apr 10, 5:16 AM CDTFlash Flood WarningLIXOrleans3 hr
Apr 10, 5:23 AM CDTSpecial Marine WarningLIX67 min
Apr 10, 5:24 AM CDTFlash Flood WarningLIXSaint Bernard3 hr
Apr 10, 5:46 AM CDTSpecial Weather StatementLIXAssumption, Jefferson, Orleans, Saint Charles59 min
Apr 10, 6:07 AM CDTAreal Flood AdvisoryLIXJefferson, Lafourche, Orleans, Saint Charles, Saint John the Baptist, Terrebonne2 hr
Apr 10, 6:24 AM CDTSpecial Marine WarningLIX96 min
Apr 10, 6:29 AM CDTFlash Flood WarningLIXLafourche, Terrebonne89 min
Apr 10, 6:42 AM CDTSpecial Weather StatementLIXJefferson, Lafourche, Plaquemines, Terrebonne78 min
Apr 10, 7:13 AM CDTSpecial Marine WarningLIX92 min
Apr 10, 7:53 AM CDTSpecial Marine WarningLIX97 min
Apr 10, 8:52 AM CDTRiver Flood WarningLIXSaint Tammany10 days
Apr 10, 8:52 AM CDTRiver Flood WarningLIXSaint Tammany24 hr
Apr 10, 8:55 AM CDTRiver Flood WarningLIXSaint Tammany25 hr
Apr 10, 9:49 AM CDTRiver Flood WarningLIXWashington33 hr
Apr 10, 11:15 AM CDTSpecial Weather StatementLIXTerrebonne30 min
Apr 10, 11:51 AM CDTSpecial Weather StatementLIXLafourche39 min
Apr 10, 12:28 PM CDTSpecial Weather StatementLIXJefferson32 min
Apr 10, 5:46 PM CDTRiver Flood WarningLIXSaint Helena26 hr

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.