Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 111, NWS New Orleans, LA

August 31, 2021Saint Charles Parish, Saint John the Baptist Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Aug 31, 2021, 6:20 PM CDT for Saint Charles Parish, Saint John the Baptist Parish, 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: Aug 31, 2021, 6:20 PM CDT (23:20 UTC)
Expired: Aug 31, 2021, 7:09 PM CDT
In force: 49 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

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

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.3 hours before the alert went out and 84 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: 321 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 871 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 186 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

616 
WGUS54 KLIX 312320
FFWLIX
LAC089-095-010115-
/O.NEW.KLIX.FF.W.0111.210831T2320Z-210901T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
620 PM CDT Tue Aug 31 2021

The National Weather Service in New Orleans has issued a

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

* Until 815 PM CDT.

* At 620 PM 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...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Laplace, Hahnville, Reserve, Montz, Killona, Taft, Norco, Edgard, 
  New Sarpy, Destrehan, Garyville, St. Rose, Luling and Wallace.

This includes the following Interstates...
	Interstate 10 from near mile marker 198 to near mile marker 221.
	Interstate 310 from near mile marker 1 to near mile marker 8.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3012 9065 3011 9050 3008 9041 3001 9028
      2991 9034 2996 9048 3003 9056 3003 9066
      3005 9066 3009 9067 3010 9065

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

1 follow-up statement

224 
WGUS74 KLIX 010009
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
709 PM CDT Tue Aug 31 2021

LAC089-095-010019-
/O.CAN.KLIX.FF.W.0111.000000T0000Z-210901T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Charles LA-St. John The Baptist LA-
709 PM CDT Tue Aug 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN ST. CHARLES AND 
WEST CENTRAL ST. JOHN THE BAPTIST PARISHES...

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

LAT...LON 3012 9065 3011 9050 3008 9041 3001 9028
      2991 9034 2996 9048 3003 9056 3003 9066
      3009 9067 3010 9065

$$

13

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 31, 4:06 AM CDT	Heat Advisory	LIX	Assumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more	38 hr
Aug 31, 10:02 AM CDT	Special Marine Warning	LIX		118 min
Aug 31, 1:21 PM CDT	Special Weather Statement	LIX	Saint Bernard	39 min
Aug 31, 1:58 PM CDT	Special Weather Statement	LIX	Saint Bernard	32 min
Aug 31, 2:49 PM CDT	Flash Flood Warning Considerable damage threat	LIX	Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles	88 min
Aug 31, 3:52 PM CDT	Special Weather Statement	LIX	Saint Charles	53 min
Aug 31, 4:23 PM CDT	Special Marine Warning	LIX		2 hr
Aug 31, 4:36 PM CDT	Special Weather Statement	LIX	Lafourche	24 min
Aug 31, 4:44 PM CDT	Flash Flood Warning Considerable damage threat	LIX	Lafourche, Saint James, Saint John the Baptist	3 hr
Aug 31, 5:05 PM CDT	Special Weather Statement	LIX	Lafourche	25 min
Aug 31, 5:22 PM CDT	Special Weather Statement	LIX	Assumption	53 min
Aug 31, 6:50 PM CDT	Flash Flood Warning	LIX	Assumption, Lafourche, Terrebonne	42 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; the sounding from the Mesonet's radiosonde archive.