Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 17, NWS New Orleans, LA

April 15, 2021Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Apr 15, 2021, 12:49 AM CDT for Saint Tammany Parish, Louisiana. It was in force for 106 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
Apr 15, 2021, 12:49 AM CDT (05:49 UTC)
Expired
Apr 15, 2021, 2:35 AM CDT
In force
106 min
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 00:00Z, 5.8 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 00:00Z on 2021-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 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 2021-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 311 square meters per square second.19395878Sfc1 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
5 J/kg
Mixed-layer CIN
-620 J/kg
Mixed-layer LCL
709 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
311 m²/s²
0-3 km storm-relative helicity
272 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

699 
WGUS54 KLIX 150549
FFWLIX
LAC103-150845-
/O.NEW.KLIX.FF.W.0017.210415T0549Z-210415T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
1249 AM CDT Thu Apr 15 2021

The National Weather Service in New Orleans has issued a

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

* Until 345 AM CDT.

* At 1249 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 2 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  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 flash flooding include...
  Slidell, Pearl River, Lacombe and Slidell Airport.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

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 3038 8986 3036 8972 3017 8971 3017 8972
      3018 8974 3018 8975 3019 8976 3021 8980
      3023 8985 3025 8987 3026 8990 3025 8993
      3026 8996 3026 8997 3027 8999 3029 8999
      3031 9000 3036 8989

FLASH FLOOD...RADAR INDICATED

$$

CAB
2 follow-up statements
453 
WGUS74 KLIX 150628
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
128 AM CDT Thu Apr 15 2021

LAC103-150845-
/O.CON.KLIX.FF.W.0017.000000T0000Z-210415T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Tammany LA-
128 AM CDT Thu Apr 15 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM CDT EARLY THIS 
MORNING FOR SOUTH CENTRAL ST. TAMMANY PARISH...

At 128 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1.5 and 4 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Doppler radar.

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 flash flooding include...
  Slidell, Pearl River, Lacombe and Slidell Airport.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

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 3038 8986 3036 8972 3017 8971 3017 8972
      3018 8974 3018 8975 3019 8976 3021 8980
      3023 8985 3025 8987 3026 8990 3025 8993
      3026 8996 3026 8997 3027 8999 3029 8999
      3031 9000 3036 8989

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1.5-3 INCHES IN 3 HOURS 

$$

CAB
701 
WGUS74 KLIX 150735
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
235 AM CDT Thu Apr 15 2021

LAC103-150745-
/O.CAN.KLIX.FF.W.0017.000000T0000Z-210415T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Tammany LA-
235 AM CDT Thu Apr 15 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL ST. TAMMANY 
PARISH...

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 1200 PM CDT Thursday for 
portions of southeast Louisiana and southern Mississippi.

LAT...LON 3038 8986 3036 8972 3017 8971 3017 8972
      3018 8974 3018 8975 3019 8976 3021 8980
      3023 8985 3025 8987 3026 8990 3025 8993
      3026 8996 3026 8997 3027 8999 3029 8999
      3031 9000 3036 8989

$$

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 14, 7:57 PM CDTSpecial Weather StatementLIXPlaquemines63 min
Apr 14, 8:00 PM CDTSpecial Marine WarningLIX2 hr
Apr 14, 8:22 PM CDTSpecial Marine WarningLIX113 min
Apr 14, 9:12 PM CDTRiver Flood WarningLIXEast Baton Rouge72 hr
Apr 14, 9:18 PM CDTRiver Flood WarningLIXSaint Helena62 hr
Apr 14, 9:18 PM CDTRiver Flood WarningLIXSaint Helena70 hr
Apr 14, 9:18 PM CDTRiver Flood WarningLIXLivingston4 days
Apr 14, 9:36 PM CDTSpecial Marine WarningLIX84 min
Apr 14, 11:04 PM CDTAreal Flood AdvisoryLIXOrleans, Saint Tammany3 hr
Apr 14, 11:06 PM CDTSpecial Marine WarningLIX84 min
Apr 14, 11:22 PM CDTSpecial Weather StatementLIXTangipahoa53 min
Apr 14, 11:36 PM CDTAreal Flood AdvisoryLIXSaint Tammany, Tangipahoa3 hr
Apr 15, 12:10 AM CDTFlash Flood WarningLIXSaint Tammany2 hr
Apr 15, 12:15 AM CDTSpecial Marine WarningLIX60 min
Apr 15, 12:24 AM CDTSpecial Weather StatementLIXSaint Tammany81 min
Apr 15, 12:33 AM CDTSevere Thunderstorm WarningLIXSaint Tammany57 min
Apr 15, 1:03 AM CDTSpecial Marine WarningLIX87 min
Apr 15, 1:07 AM CDTSpecial Marine WarningLIX98 min
Apr 15, 1:38 AM CDTSpecial Marine WarningLIX97 min
Apr 15, 2:01 AM CDTSpecial Weather StatementLIXSaint Helena44 min
Apr 15, 2:03 AM CDTSpecial Weather StatementLIXWashington57 min
Apr 15, 2:27 AM CDTSpecial Marine WarningLIX33 min
Apr 15, 2:38 AM CDTSevere Thunderstorm WarningLIXSaint Helena, Tangipahoa, Washington27 min
Apr 15, 3:23 AM CDTSpecial Marine WarningLIX22 min
Apr 15, 3:50 AM CDTSpecial Marine WarningLIX55 min
Apr 15, 4:06 AM CDTSmall Craft AdvisoryLIX12 hr
Apr 15, 4:36 AM CDTSevere Thunderstorm WarningLIXEast Feliciana24 min
Apr 15, 4:46 AM CDTSpecial Marine WarningLIX44 min
Apr 15, 4:58 AM CDTSpecial Weather StatementLIXSaint Helena47 min
Apr 15, 5:03 AM CDTSpecial Weather StatementLIXPointe Coupee42 min
Apr 15, 5:59 AM CDTSpecial Weather StatementLIXAscension, Livingston, Saint James31 min
Apr 15, 6:11 AM CDTSpecial Weather StatementLIXWashington34 min
Apr 15, 6:16 AM CDTSpecial Marine WarningLIX59 min
Apr 15, 6:22 AM CDTSpecial Weather StatementLIXAssumption53 min
Apr 15, 6:28 AM CDTSevere Thunderstorm WarningLIXAscension, Saint Charles, Saint James, Saint John the Baptist18 min
Apr 15, 6:38 AM CDTRiver Flood WarningLIXWashington3 days
Apr 15, 7:01 AM CDTSpecial Weather StatementLIXOrleans, Saint Charles44 min
Apr 15, 7:10 AM CDTSpecial Marine WarningLIX65 min
Apr 15, 7:40 AM CDTSpecial Weather StatementLIXTerrebonne50 min
Apr 15, 7:45 AM CDTSpecial Weather StatementLIXOrleans30 min
Apr 15, 7:57 AM CDTSpecial Marine WarningLIX63 min
Apr 15, 8:01 AM CDTSpecial Marine WarningLIX29 min
Apr 15, 8:04 AM CDTSpecial Marine WarningLIX56 min
Apr 15, 8:16 AM CDTSpecial Weather StatementLIXJefferson, Plaquemines89 min
Apr 15, 8:40 AM CDTSpecial Marine WarningLIX95 min
Apr 15, 8:57 AM CDTSpecial Marine WarningLIX63 min
Apr 15, 9:58 AM CDTSpecial Marine WarningLIX92 min
Apr 15, 10:04 AM CDTRiver Flood WarningLIXAscension, Livingston21 days
Apr 15, 10:04 AM CDTRiver Flood WarningLIXAscension, Livingston5 days
Apr 15, 10:14 AM CDTRiver Flood WarningLIXTangipahoa27 hr
Apr 15, 11:15 AM CDTSpecial Weather StatementLIXLafourche60 min
Apr 15, 11:16 AM CDTRiver Flood WarningLIXTangipahoa21 hr
Apr 15, 11:21 AM CDTSpecial Marine WarningLIX54 min
Apr 15, 11:49 AM CDTSpecial Marine WarningLIX42 min
Apr 15, 12:39 PM CDTSpecial Marine WarningLIX66 min
Apr 15, 12:46 PM CDTSpecial Marine WarningLIX59 min
Apr 15, 1:38 PM CDTSpecial Marine WarningLIX67 min
Apr 15, 1:41 PM CDTSpecial Marine WarningLIX12 min
Apr 15, 2:40 PM CDTSpecial Marine WarningLIX45 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.