Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 127, NWS New Orleans, LA

September 17, 2021Ascension Parish, Livingston Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Sep 17, 2021, 4:54 PM CDT for Ascension Parish, Livingston Parish, Louisiana. It was in force for 38 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: Sep 17, 2021, 4:54 PM CDT (21:54 UTC)
Expired: Sep 17, 2021, 5:32 PM CDT
In force: 38 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

Counties Ascension Parish, LA, Livingston Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 9.9 hours before the alert went out and 115 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: 1826 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 687 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

034 
WGUS54 KLIX 172154
FFWLIX
LAC005-063-180100-
/O.NEW.KLIX.FF.W.0127.210917T2154Z-210918T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
454 PM CDT Fri Sep 17 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  North Central Ascension Parish in southeastern Louisiana...
  Southwestern Livingston Parish in southeastern Louisiana...

* Until 800 PM CDT.

* At 454 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 3 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...
  Gonzales, French Settlement, Port Vincent, Whitehall and 
  Prairieville.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 171 and 172.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3036 9092 3045 9087 3036 9063 3017 9080
      3030 9102 3034 9095 3034 9094 3035 9092
      3034 9091 3035 9089 3036 9091

FLASH FLOOD...RADAR INDICATED

$$

BL

1 follow-up statement

284 
WGUS74 KLIX 172232
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
532 PM CDT Fri Sep 17 2021

LAC005-063-172242-
/O.CAN.KLIX.FF.W.0127.000000T0000Z-210918T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Ascension LA-Livingston LA-
532 PM CDT Fri Sep 17 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL ASCENSION AND 
SOUTHWESTERN LIVINGSTON PARISHES...

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

A Flash Flood Watch remains in effect until 700 PM CDT Saturday for 
portions of southeast Louisiana and Mississippi.

LAT...LON 3036 9092 3045 9087 3036 9063 3017 9080
      3030 9102 3034 9095 3034 9094 3035 9092
      3034 9091 3035 9089 3036 9091

$$

BL

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 16, 7:00 PM CDT	River Flood Warning	LIX	Ascension, Livingston	29 hr
Sep 17, 6:07 AM CDT	Areal Flood Advisory	LIX	Saint Helena, Tangipahoa	3 hr
Sep 17, 7:04 AM CDT	Flash Flood Warning	LIX	Saint Helena	88 min
Sep 17, 7:17 AM CDT	Special Weather Statement	LIX	Livingston	28 min
Sep 17, 7:22 AM CDT	Special Marine Warning	LIX		38 min
Sep 17, 7:32 AM CDT	Special Weather Statement	LIX	Saint Bernard	58 min
Sep 17, 7:44 AM CDT	Special Weather Statement	LIX	Jefferson	46 min
Sep 17, 7:57 AM CDT	Special Marine Warning	LIX		2 hr
Sep 17, 8:15 AM CDT	Special Marine Warning	LIX		2 hr
Sep 17, 8:45 AM CDT	Special Marine Warning	LIX		2 hr
Sep 17, 9:19 AM CDT	Special Weather Statement	LIX	Lafourche	41 min
Sep 17, 9:28 AM CDT	Special Weather Statement	LIX	Tangipahoa	62 min
Sep 17, 9:33 AM CDT	Special Weather Statement	LIX	Tangipahoa	57 min
Sep 17, 10:18 AM CDT	Special Weather Statement	LIX	Saint Charles	117 min
Sep 17, 10:30 AM CDT	Special Marine Warning	LIX		2 hr
Sep 17, 10:58 AM CDT	Special Weather Statement	LIX	Jefferson	32 min
Sep 17, 11:12 AM CDT	Special Marine Warning	LIX		59 min
Sep 17, 11:27 AM CDT	Special Marine Warning	LIX		2 hr
Sep 17, 11:41 AM CDT	Special Marine Warning	LIX		94 min
Sep 17, 11:53 AM CDT	Special Weather Statement	LIX	Jefferson	52 min
Sep 17, 11:54 AM CDT	Special Marine Warning	LIX		66 min
Sep 17, 12:07 PM CDT	Special Marine Warning	LIX		113 min
Sep 17, 12:31 PM CDT	Special Weather Statement	LIX	Tangipahoa	59 min
Sep 17, 12:35 PM CDT	Special Marine Warning	LIX		25 min
Sep 17, 12:56 PM CDT	Special Marine Warning	LIX		94 min
Sep 17, 1:12 PM CDT	Special Marine Warning	LIX		2 hr

Nearby

Flash Flood Warnings in Louisiana, 2021 Every 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.