Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 99, NWS New Orleans, LA

August 30, 2021Livingston Parish, Saint Helena Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Aug 30, 2021, 1:24 AM CDT for Livingston Parish, Saint Helena Parish, Louisiana. It was in force for 8 hr. 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 30, 2021, 1:24 AM CDT (06:24 UTC)
Expired
Aug 30, 2021, 9:01 AM CDT
In force
8 hr
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Livingston Parish, LA, Saint Helena Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 6.4 hours before the alert went out and 108 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 2021-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 25 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 00:00Z on 2021-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.1939587897Sfc1 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
25 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
679 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

018 
WGUS54 KLIX 300624
FFWLIX
LAC063-091-301030-
/O.NEW.KLIX.FF.W.0099.210830T0624Z-210830T1030Z/
/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
124 AM CDT Mon Aug 30 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Southeastern St. Helena Parish in southeastern Louisiana...
  North central Livingston Parish in southeastern Louisiana...

* Until 530 AM CDT.

* At 123 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 4 to 8 inches of rain have 
  fallen. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  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 flooding include...
  Livingston and Montpelier. 

This includes Interstate 12 near mile marker 20.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3081 9064 3060 9062 3046 9080 3081 9081

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...2-3 INCHES IN 1 HOUR

$$

tingler
2 follow-up statements
858 
WGUS54 KLIX 301021
FFWLIX
LAC063-091-301430-
/O.EXT.KLIX.FF.W.0099.000000T0000Z-210830T1430Z/
/00000.U.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
521 AM CDT Mon Aug 30 2021

The National Weather Service in New Orleans has extended the

* Flash Flood Warning for...
  North Central Livingston Parish in southeastern Louisiana...
  Southeastern St. Helena Parish in southeastern Louisiana...

* Until 930 AM CDT.

* At 521 AM CDT, Doppler radar indicated that heavy rainfall has 
  ended, however runoff from previous heavy rain will continue for 
  several more hours. Between 4 and 10 inches of rain have fallen. 
  Flash flooding is already occurring.

  HAZARD...Flash flooding caused by heavy rain.

  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.

This includes the following Interstates...
	Interstate 12 near mile marker 20.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3081 9064 3060 9062 3046 9080 3081 9081

FLASH FLOOD...RADAR INDICATED

$$
467 
WGUS74 KLIX 301401
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
901 AM CDT Mon Aug 30 2021

LAC063-091-301411-
/O.CAN.KLIX.FF.W.0099.000000T0000Z-210830T1430Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Livingston LA-St. Helena LA-
901 AM CDT Mon Aug 30 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL LIVINGSTON AND 
SOUTHEASTERN ST. HELENA PARISHES...

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

LAT...LON 3081 9064 3060 9062 3046 9080 3081 9081

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 7:48 PM CDTFlash Flood Warning Considerable damage threatLIXSaint Charles, Saint John the Baptist2 hr
Aug 29, 8:00 PM CDTSpecial Marine WarningLIX30 min
Aug 29, 8:22 PM CDTTornado WarningLIXSaint Tammany38 min
Aug 29, 8:35 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXSaint Charles, Saint John the Baptist6 hr
Aug 29, 8:55 PM CDTFlash Flood Warning EmergencyConsiderable damage threatLIXLivingston, Tangipahoa3 hr
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany12 days
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany21 days
Aug 29, 9:05 PM CDTRiver Flood WarningLIXWashington63 hr
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany, Washington11 days
Aug 29, 10:39 PM CDTSpecial Marine WarningLIX51 min
Aug 29, 10:48 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXJefferson15 hr
Aug 29, 10:55 PM CDTSpecial Marine WarningLIX20 min
Aug 29, 11:45 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXPlaquemines10 hr
Aug 29, 11:50 PM CDTFlash Flood Warning Considerable damage threatLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington3 hr
Aug 30, 12:05 AM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXLivingston, Tangipahoa12 hr
Aug 30, 2:24 AM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXSaint Charles, Saint John the Baptist8 hr
Aug 30, 2:39 AM CDTFlash Flood Warning Considerable damage threatLIXSaint Tammany9 hr
Aug 30, 2:55 AM CDTFlash Flood Warning Considerable damage threatLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington5 hr
Aug 30, 3:55 AM CDTFlash Flood WarningLIXEast Feliciana, Saint Helena, Tangipahoa, Washington5 hr
Aug 30, 4:19 AM CDTSmall Craft AdvisoryLIX39 hr
Aug 30, 4:51 AM CDTCoastal Flood AdvisoryLIXAssumption15 hr
Aug 30, 7:15 AM CDTSpecial Marine WarningLIX30 min
Aug 30, 7:18 AM CDTSpecial Marine WarningLIX27 min
Aug 30, 7:45 AM CDTFlash Flood WarningLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington3 hr
Aug 30, 9:01 AM CDTSpecial Marine WarningLIX89 min
Aug 30, 9:58 AM CDTAreal Flood WarningLIXJefferson, Lafourche, Livingston, Plaquemines, Saint Charles, Saint James and 1 more60 hr
Aug 30, 10:53 AM CDTAreal Flood WarningLIXSaint Tammany, Tangipahoa, Washington35 hr
Aug 30, 11:04 AM CDTAreal Flood WarningLIXSaint Helena, Saint Tammany, Tangipahoa, Washington35 hr
Aug 30, 11:34 AM CDTAreal Flood WarningLIXSaint Tammany, Washington34 hr
Aug 30, 12:24 PM CDTAreal Flood WarningLIXAscension, Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa33 hr
Aug 30, 2:57 PM CDTHeat AdvisoryLIXAssumption, East Baton Rouge, Iberville, Orleans, Saint Bernard, Saint James and 2 more26 hr
Aug 30, 6:10 PM CDTSpecial Marine WarningLIX95 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.