Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 116, NWS New Orleans, LA

September 14, 20214 parishes in Louisiana

NWS New Orleans, LA issued this flash flood warning at Sep 14, 2021, 11:41 AM CDT for 4 parishes in Louisiana. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 14, 2021, 11:41 AM CDT (16:41 UTC)
Expired: Sep 14, 2021, 2:45 PM CDT
In force: 3 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

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

What was reported inside it

Time	Report	Where	Remark
Sep 14, 1:12 PM CDT	FLASH FLOOD	4 Sw East New Orleans, LA	NOHSEP REPORTED MULTIPLE UNDERPASSES TO BE IMPASSABLE DUE TO HIGH WATER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.7 hours before the alert went out and 47 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: 428 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 736 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

012 
WGUS54 KLIX 141641
FFWLIX
LAC051-071-075-087-141945-
/O.NEW.KLIX.FF.W.0116.210914T1641Z-210914T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
1141 AM CDT Tue Sep 14 2021

The National Weather Service in New Orleans has issued a

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

* Until 245 PM CDT.

* At 1141 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. 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...
  New Orleans, Harvey, Timberlane, Marrero, Chalmette, Belle Chasse, 
  Metairie, Avondale, Jefferson, Gretna, Westwego, Terrytown, Arabi, 
  Woodmere, Bridge City, Estelle, Elmwood and Lakefront Airport.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 227 and 245.
	Interstate 510 between mile markers 2 and 3.
	Interstate 610 between mile markers 1 and 4.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2985 9017 3001 9019 3002 9017 3002 9013
      3003 9009 3003 9008 3003 9006 3003 9003
      3005 9003 3004 9002 3006 8998 3004 8993
      2999 8991 2991 8996 2984 9003 2982 9012
      2982 9015

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

1 follow-up statement

614 
WGUS74 KLIX 141947
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
247 PM CDT Tue Sep 14 2021

LAC051-071-075-087-141957-
/O.EXP.KLIX.FF.W.0116.000000T0000Z-210914T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-Orleans LA-Plaquemines LA-St. Bernard LA-
247 PM CDT Tue Sep 14 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR NORTH CENTRAL JEFFERSON, 
SOUTHWESTERN ORLEANS, NORTHWESTERN PLAQUEMINES AND WEST CENTRAL ST. 
BERNARD PARISHES...

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 AM CDT Thursday for 
portions of southeast Louisiana and Mississippi.

LAT...LON 2985 9017 3001 9019 3002 9017 3002 9013
      3003 9009 3003 9008 3003 9006 3003 9003
      3005 9003 3004 9002 3006 8998 3004 8993
      2999 8991 2991 8996 2984 9003 2982 9012
      2982 9015

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 14, 4:08 AM CDT	Coastal Flood Advisory	LIX	Orleans, Saint Bernard, Saint Tammany	63 hr
Sep 14, 5:07 AM CDT	Special Weather Statement	LIX	East Baton Rouge	53 min
Sep 14, 6:52 AM CDT	Special Weather Statement	LIX	East Baton Rouge, Livingston	38 min
Sep 14, 7:48 AM CDT	Areal Flood Advisory	LIX	Saint Tammany, Washington	3 hr
Sep 14, 9:30 AM CDT	Areal Flood Advisory	LIX	Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Pointe Coupee and 2 more	2 hr
Sep 14, 9:34 AM CDT	River Flood Warning	LIX	Saint Tammany	54 hr
Sep 14, 9:34 AM CDT	River Flood Warning	LIX	Saint Tammany	72 hr
Sep 14, 9:34 AM CDT	River Flood Warning	LIX	Tangipahoa	7 days
Sep 14, 10:41 AM CDT	Areal Flood Advisory	LIX	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 1 more	2 hr
Sep 14, 11:45 AM CDT	Special Marine Warning	LIX		30 min
Sep 14, 12:07 PM CDT	Special Marine Warning	LIX		53 min
Sep 14, 2:20 PM CDT	Special Marine Warning	LIX		40 min
Sep 14, 3:25 PM CDT	Special Marine Warning	LIX		65 min
Sep 14, 3:36 PM CDT	Special Marine Warning	LIX		54 min
Sep 14, 4:32 PM CDT	Special Marine Warning	LIX		58 min
Sep 14, 4:44 PM CDT	Special Marine Warning	LIX		29 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.