Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 26, NWS New Orleans, LA

May 10, 20214 parishes in Louisiana

NWS New Orleans, LA issued this flash flood warning at May 10, 2021, 4:20 AM CDT for 4 parishes in Louisiana. It was in force for 115 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
May 10, 2021, 4:20 AM CDT (09:20 UTC)
Expired
May 10, 2021, 6:15 AM CDT
In force
115 min
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

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 9.3 hours before the alert went out and 50 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 2021-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 186 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 00:00Z on 2021-05-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 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
186 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
1292 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

440 
WGUS54 KLIX 100920
FFWLIX
LAC051-071-075-087-101115-
/O.NEW.KLIX.FF.W.0026.210510T0920Z-210510T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
420 AM CDT Mon May 10 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 615 AM CDT.

* At 420 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 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...
  New Orleans, Belle Chasse, Chalmette, Timberlane, Harvey, Gretna, 
  Meraux, Violet, Terrytown, Poydras, Arabi and Woodmere.

Additional rainfall amounts of 2 to 3 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 2983 9007 2992 9004 2997 9002 2997 8986
      2977 8990

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

$$

TE

The office that day

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

IssuedProductOfficeCountiesLasted
May 9, 8:48 PM CDTFlash Flood WatchLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more15 hr
May 10, 1:00 AM CDTSpecial Weather StatementLIXAscension, Livingston60 min
May 10, 1:29 AM CDTAreal Flood AdvisoryLIXAscension, Assumption, Iberville, Saint James70 min
May 10, 1:49 AM CDTSpecial Weather StatementLIXAssumption, Saint James, Saint John the Baptist56 min
May 10, 1:54 AM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Saint James51 min
May 10, 2:01 AM CDTSpecial Marine WarningLIX59 min
May 10, 2:43 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles2 hr
May 10, 2:52 AM CDTSpecial Marine WarningLIX53 min
May 10, 2:57 AM CDTFlash Flood WarningLIXJefferson, Orleans, Saint Charles9 hr
May 10, 3:25 AM CDTSpecial Weather StatementLIXOrleans35 min
May 10, 3:37 AM CDTSpecial Marine WarningLIX113 min
May 10, 3:41 AM CDTTornado WarningLIXOrleans, Plaquemines, Saint Bernard18 min
May 10, 5:26 AM CDTSpecial Marine WarningLIX64 min
May 10, 5:29 AM CDTSpecial Marine WarningLIX2 hr
May 10, 5:38 AM CDTSpecial Weather StatementLIXWest Baton Rouge67 min
May 10, 6:04 AM CDTSpecial Weather StatementLIXEast Baton Rouge, West Baton Rouge56 min
May 10, 6:16 AM CDTSpecial Weather StatementLIXSaint Charles44 min
May 10, 6:36 AM CDTSpecial Marine WarningLIX54 min
May 10, 7:25 AM CDTSpecial Weather StatementLIXSaint John the Baptist50 min
May 10, 7:34 AM CDTSpecial Marine WarningLIX56 min
May 10, 7:51 AM CDTSevere Thunderstorm WarningLIXIberville, Pointe Coupee, West Baton Rouge54 min
May 10, 8:23 AM CDTSpecial Marine WarningLIX67 min
May 10, 8:28 AM CDTSevere Thunderstorm WarningLIXAscension, East Baton Rouge, Iberville, Livingston, Pointe Coupee, West Baton Rouge62 min
May 10, 9:16 AM CDTSevere Thunderstorm WarningLIXAscension, Assumption, East Baton Rouge, Iberville, Livingston, Saint James and 2 more44 min
May 10, 9:38 AM CDTTornado WarningLIXAscension, Livingston, Saint James, Saint John the Baptist20 min
May 10, 9:57 AM CDTSpecial Weather StatementLIXAssumption, Orleans, Saint Charles, Saint James, Saint John the Baptist, Saint Tammany63 min
May 10, 10:29 AM CDTSpecial Marine WarningLIX61 min
May 10, 11:08 AM CDTSpecial Weather StatementLIXOrleans52 min
May 10, 11:17 AM CDTSpecial Marine WarningLIX58 min
May 10, 12:10 PM CDTSpecial Marine WarningLIX65 min
May 10, 12:14 PM CDTSpecial Marine WarningLIX91 min
May 10, 1:08 PM CDTSpecial Marine WarningLIX67 min
May 10, 1:44 PM CDTSpecial Marine WarningLIX28 min
May 10, 2:09 PM CDTSpecial Marine WarningLIX66 min
May 10, 3:09 PM CDTSpecial Marine WarningLIX96 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.