Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 72, NWS New Orleans, LA

July 11, 20214 parishes in Louisiana

NWS New Orleans, LA issued this flash flood warning at Jul 11, 2021, 5:12 PM CDT for 4 parishes in Louisiana. It was in force for 49 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
Jul 11, 2021, 5:12 PM CDT (22:12 UTC)
Expired
Jul 11, 2021, 6:01 PM CDT
In force
49 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Jefferson Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 10.2 hours before the alert went out and 56 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 2021-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2500 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, Slidell Radar S, LA at 12:00Z on 2021-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
2500 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
707 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

704 
WGUS54 KLIX 112212
FFWLIX
LAC051-071-087-089-120015-
/O.NEW.KLIX.FF.W.0072.210711T2212Z-210712T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
512 PM CDT Sun Jul 11 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Northwestern Jefferson Parish in southeastern Louisiana...
  Southwestern Orleans Parish in southeastern Louisiana...
  West Central St. Bernard Parish in southeastern Louisiana...
  North Central St. Charles Parish in southeastern Louisiana...

* Until 715 PM CDT.

* At 512 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 2 inches of 
  rain have fallen. The expected rainfall rate is 1.5 to 3 inches in 
  45 minutes. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  New Orleans, Metairie, Avondale, Marrero, Hahnville, Chalmette, 
  Jefferson, Gretna, Harahan, Westwego, Elmwood, River Ridge, 
  Waggaman, Bridge City, Ama, St. Rose, Destrehan, Luling, New Sarpy 
  and Arabi.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 215 and 243.
	Interstate 610 between mile markers 1 and 4.
	Interstate 310 between mile markers 1 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2997 9046 3006 9038 3002 9016 3004 9001
      3002 8994 2995 8993 2992 8994 2995 9006
      2992 9007 2991 9013 2996 9015 2992 9021
      2997 9025 2997 9028 2989 9041

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1.5-3 INCHES IN 45 MINUTES

$$

CAB
2 follow-up statements
905 
WGUS74 KLIX 112254
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
554 PM CDT Sun Jul 11 2021

LAC087-112304-
/O.CAN.KLIX.FF.W.0072.000000T0000Z-210712T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Bernard LA-
554 PM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING IS CANCELLED FOR WEST CENTRAL ST. BERNARD 
PARISH...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 2997 9046 3003 9041 3002 9016 3001 9005
      3001 9001 2998 9001 2995 9001 2995 9006
      2992 9007 2993 9013 2996 9015 2994 9020
      2997 9025 2997 9028 2993 9035

$$

LAC051-071-089-120015-
/O.CON.KLIX.FF.W.0072.000000T0000Z-210712T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-Orleans LA-St. Charles LA-
554 PM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM CDT THIS 
EVENING FOR NORTHWESTERN JEFFERSON, WEST CENTRAL ORLEANS AND NORTH 
CENTRAL ST. CHARLES PARISHES...

At 554 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 2.5 inches of rain have 
fallen. Additional rainfall amounts of less than an inch 1 are 
possible in the warned area. Some flash flooding is ongoing but 
heavy rain is ending and streets should begin to drain quickly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  New Orleans, Metairie, Hahnville, Jefferson, Gretna, Harahan, 
  River Ridge, Waggaman, Elmwood, Bridge City, St. Rose, Destrehan, 
  Luling, New Sarpy, Norco, Taft, Arabi and New Orleans Armstrong 
  Airport.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 219 and 241.
	Interstate 610 between mile markers 1 and 4.
	Interstate 310 between mile markers 1 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2997 9046 3003 9041 3002 9016 3001 9005
      3001 9001 2998 9001 2995 9001 2995 9006
      2992 9007 2993 9013 2996 9015 2994 9020
      2997 9025 2997 9028 2993 9035

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1.5-3 INCHES IN 45 MINUTES

$$

CAB
985 
WGUS74 KLIX 112301
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
601 PM CDT Sun Jul 11 2021

LAC051-071-089-112311-
/O.CAN.KLIX.FF.W.0072.000000T0000Z-210712T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-Orleans LA-St. Charles LA-
601 PM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN JEFFERSON, WEST 
CENTRAL ORLEANS AND NORTH CENTRAL ST. CHARLES PARISHES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 2997 9046 3003 9041 3002 9016 3001 9005
      3001 9001 2998 9001 2995 9001 2995 9006
      2992 9007 2993 9013 2996 9015 2994 9020
      2997 9025 2997 9028 2993 9035

$$

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 7:36 AM CDTSpecial Weather StatementLIXSaint James39 min
Jul 11, 10:13 AM CDTSpecial Weather StatementLIXOrleans47 min
Jul 11, 10:18 AM CDTSpecial Marine WarningLIX48 min
Jul 11, 11:07 AM CDTSpecial Marine WarningLIX83 min
Jul 11, 11:09 AM CDTSpecial Weather StatementLIXOrleans36 min
Jul 11, 11:10 AM CDTSpecial Weather StatementLIXTerrebonne35 min
Jul 11, 12:47 PM CDTSpecial Weather StatementLIXSaint Helena, Tangipahoa58 min
Jul 11, 1:25 PM CDTSpecial Weather StatementLIXWashington80 min
Jul 11, 1:37 PM CDTSpecial Weather StatementLIXWashington68 min
Jul 11, 1:58 PM CDTAreal Flood AdvisoryLIXSaint Tammany, Tangipahoa, Washington2 hr
Jul 11, 2:19 PM CDTSpecial Weather StatementLIXEast Baton Rouge, West Baton Rouge71 min
Jul 11, 2:27 PM CDTAreal Flood AdvisoryLIXEast Baton Rouge, Livingston, Saint Helena, West Baton Rouge99 min
Jul 11, 3:13 PM CDTSpecial Weather StatementLIXTangipahoa77 min
Jul 11, 3:15 PM CDTSpecial Marine WarningLIX90 min
Jul 11, 3:52 PM CDTSpecial Weather StatementLIXAscension, Saint John the Baptist38 min
Jul 11, 3:55 PM CDTSpecial Weather StatementLIXSaint Tammany65 min
Jul 11, 4:02 PM CDTSpecial Marine WarningLIX58 min
Jul 11, 4:14 PM CDTSpecial Marine WarningLIX61 min
Jul 11, 4:21 PM CDTAreal Flood AdvisoryLIXSaint John the Baptist89 min
Jul 11, 4:28 PM CDTAreal Flood AdvisoryLIXSaint Tammany93 min
Jul 11, 4:32 PM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Saint Bernard40 min
Jul 11, 5:03 PM CDTSpecial Weather StatementLIXSaint Charles27 min
Jul 11, 5:06 PM CDTSpecial Marine WarningLIX54 min
Jul 11, 6:08 PM CDTSpecial Marine WarningLIX67 min
Jul 11, 6:47 PM CDTSpecial Marine WarningLIX58 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.