Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 56, NWS New Orleans, LA

June 21, 2021Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Jun 21, 2021, 3:57 PM CDT for Saint Tammany Parish, Louisiana. It was in force for 2 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
Jun 21, 2021, 3:57 PM CDT (20:57 UTC)
Expired
Jun 21, 2021, 6:24 PM CDT
In force
2 hr
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

County Saint Tammany Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 9.0 hours before the alert went out and 15 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 2021-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 730 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2021-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
730 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
990 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

417 
WGUS54 KLIX 212057
FFWLIX
LAC103-220000-
/O.NEW.KLIX.FF.W.0056.210621T2057Z-210622T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
357 PM CDT Mon Jun 21 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Southeastern St. Tammany Parish in southeastern Louisiana...

* Until 700 PM CDT.

* At 357 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 4 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...
  Slidell, Pearl River, Lacombe and Slidell Airport.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 261 and 272.
	Interstate 12 between mile markers 73 and 84.
	Interstate 59 in Louisiana between mile markers 1 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3031 9000 3049 8983 3043 8968 3041 8968
      3039 8968 3031 8965 3018 8975 3019 8976
      3021 8979 3023 8985 3024 8985 3025 8987
      3026 8990 3025 8993 3026 8996 3026 8998
      3027 8999 3029 8999

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-4 INCHES IN 1 HOUR

$$

CAB
3 follow-up statements
315 
WGUS74 KLIX 212149
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
449 PM CDT Mon Jun 21 2021

LAC103-220000-
/O.CON.KLIX.FF.W.0056.000000T0000Z-210622T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Tammany LA-
449 PM CDT Mon Jun 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING 
FOR SOUTHEASTERN ST. TAMMANY PARISH...

At 449 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2.5 inches of rain have 
fallen. The expected rainfall rate is 1 to 4 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. Rain has slacked off for
         now but additional heavy rain will move in shortly.

Some locations that will experience flash flooding include...
  Slidell, Pearl River, Lacombe and Slidell Airport.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 261 and 272.
	Interstate 12 between mile markers 73 and 84.
	Interstate 59 in Louisiana between mile markers 1 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3031 9000 3049 8983 3043 8968 3041 8968
      3039 8968 3031 8965 3018 8975 3019 8976
      3021 8979 3023 8985 3024 8985 3025 8987
      3026 8990 3025 8993 3026 8996 3026 8998
      3027 8999 3029 8999

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-4 INCHES IN 1 HOUR

$$

CAB
079 
WGUS74 KLIX 212310
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
610 PM CDT Mon Jun 21 2021

LAC103-220000-
/O.CON.KLIX.FF.W.0056.000000T0000Z-210622T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Tammany LA-
610 PM CDT Mon Jun 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING 
FOR SOUTHEASTERN ST. TAMMANY PARISH...

At 610 PM 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 0.5 to 2 inches in 1 hour. 
Additional rainfall amounts of 0.5 to 1.5 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...
  Slidell, Pearl River, Lacombe and Slidell Airport.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 261 and 272.
	Interstate 12 between mile markers 73 and 84.
	Interstate 59 in Louisiana between mile markers 1 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3031 9000 3049 8983 3043 8968 3041 8968
      3039 8968 3031 8965 3018 8975 3019 8976
      3021 8979 3023 8985 3024 8985 3025 8987
      3026 8990 3025 8993 3026 8996 3026 8998
      3027 8999 3029 8999

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.5-2 INCHES IN 1 HOUR

$$

CAB
319 
WGUS74 KLIX 212324
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
624 PM CDT Mon Jun 21 2021

LAC103-212334-
/O.CAN.KLIX.FF.W.0056.000000T0000Z-210622T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Tammany LA-
624 PM CDT Mon Jun 21 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN ST. TAMMANY 
PARISH...

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

LAT...LON 3031 9000 3049 8983 3043 8968 3041 8968
      3039 8968 3031 8965 3018 8975 3019 8976
      3021 8979 3023 8985 3024 8985 3025 8987
      3026 8990 3025 8993 3026 8996 3026 8998
      3027 8999 3029 8999

$$

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 21, 8:59 AM CDTSpecial Weather StatementLIXEast Baton Rouge, Livingston46 min
Jun 21, 10:15 AM CDTSpecial Weather StatementLIXLivingston30 min
Jun 21, 10:26 AM CDTSpecial Marine WarningLIX94 min
Jun 21, 10:31 AM CDTSpecial Marine WarningLIX119 min
Jun 21, 10:52 AM CDTSevere Thunderstorm WarningLIXSaint Tammany, Tangipahoa33 min
Jun 21, 10:59 AM CDTSpecial Marine WarningLIX61 min
Jun 21, 12:25 PM CDTSpecial Marine WarningLIX2 hr
Jun 21, 12:33 PM CDTSpecial Weather StatementLIXSaint James57 min
Jun 21, 1:11 PM CDTSevere Thunderstorm WarningLIXTerrebonne64 min
Jun 21, 2:21 PM CDTSpecial Marine WarningLIX39 min
Jun 21, 2:39 PM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Saint Bernard, Saint Charles3 hr
Jun 21, 2:51 PM CDTSpecial Marine WarningLIX84 min
Jun 21, 3:03 PM CDTSevere Thunderstorm WarningLIXTerrebonne42 min
Jun 21, 3:28 PM CDTAreal Flood AdvisoryLIXSaint Tammany29 min
Jun 21, 3:28 PM CDTSpecial Weather StatementLIXSaint Tammany32 min
Jun 21, 3:39 PM CDTFlash Flood WarningLIXJefferson, Orleans, Saint Charles3 hr
Jun 21, 3:39 PM CDTSpecial Weather StatementLIXLafourche36 min
Jun 21, 3:43 PM CDTSpecial Marine WarningLIX92 min
Jun 21, 3:53 PM CDTAreal Flood AdvisoryLIXLafourche, Saint Charles, Terrebonne3 hr
Jun 21, 4:16 PM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Saint Charles, Saint John the Baptist44 min
Jun 21, 4:24 PM CDTSpecial Marine WarningLIX96 min
Jun 21, 4:29 PM CDTSpecial Weather StatementLIXIberville, Pointe Coupee, West Feliciana31 min
Jun 21, 5:04 PM CDTSpecial Weather StatementLIXEast Feliciana56 min
Jun 21, 5:10 PM CDTSpecial Marine WarningLIX54 min
Jun 21, 5:18 PM CDTSevere Thunderstorm WarningLIXSaint Tammany42 min
Jun 21, 5:59 PM CDTSpecial Marine WarningLIX31 min
Jun 21, 6:38 PM CDTSpecial Marine WarningLIX52 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.