Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 22, NWS New Orleans, LA

May 5, 2021Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at May 5, 2021, 7:01 AM CDT for Saint Tammany Parish, Louisiana. It was in force for 89 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 5, 2021, 7:01 AM CDT (12:01 UTC)
Expired
May 5, 2021, 8:30 AM CDT
In force
89 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

County Saint Tammany Parish, LA

What was reported inside it

TimeReportWhereRemark
May 5, 8:00 AM CDTFLASH FLOOD3 Ene Mandeville, LAVIOLA ST. IN MANDEVILLE COVERED BY WATER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 0.0 hours before the alert went out and 40 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 2021-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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 2021-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.193958Sfc1 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
6 J/kg
Mixed-layer CIN
-305 J/kg
Mixed-layer LCL
750 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.2

Open this sounding in Storm Lab

The text

As transmitted.

245 
WGUS54 KLIX 051201
FFWLIX
LAC103-051330-
/O.NEW.KLIX.FF.W.0022.210505T1201Z-210505T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
701 AM CDT Wed May 5 2021

The National Weather Service in New Orleans has issued a

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

* Until 830 AM CDT.

* At 701 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 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...
  Madisonville and Lacombe.

This includes the following Interstates...
	Interstate 12 between mile markers 66 and 69.

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 3039 9019 3043 9001 3033 8995 3032 9001
      3032 9004 3035 9005 3036 9009 3037 9012
      3038 9017 3038 9018

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR AND 30 MINUTES

$$

TE

The office that day

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

IssuedProductOfficeCountiesLasted
May 4, 7:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 8:03 PM CDTSpecial Weather StatementLIXTangipahoa27 min
May 4, 8:13 PM CDTSpecial Weather StatementLIXWashington17 min
May 4, 8:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 9:06 PM CDTRiver Flood WarningLIXSaint Tammany69 hr
May 4, 10:03 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint John the Baptist, Tangipahoa27 min
May 4, 10:06 PM CDTSpecial Marine WarningLIX24 min
May 4, 10:25 PM CDTSpecial Marine WarningLIX65 min
May 4, 10:28 PM CDTSevere Thunderstorm WarningLIXSaint John the Baptist, Tangipahoa5 min
May 5, 12:47 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Saint Bernard, Saint Charles, Saint James, Saint John the Baptist103 min
May 5, 1:15 AM CDTSpecial Weather StatementLIXOrleans45 min
May 5, 4:24 AM CDTAreal Flood AdvisoryLIXSaint Tammany3 hr
May 5, 6:16 AM CDTRiver Flood WarningLIXSaint Tammany25 hr
May 5, 6:45 AM CDTAreal Flood AdvisoryLIXSaint Charles, Saint James, Saint John the Baptist2 hr
May 5, 7:20 AM CDTFlash Flood WarningLIXSaint Charles, Saint James, Saint John the Baptist115 min
May 5, 7:39 AM CDTSpecial Marine WarningLIX36 min
May 5, 7:48 AM CDTAreal Flood AdvisoryLIXOrleans, Saint Tammany117 min
May 5, 8:00 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles2 hr
May 5, 8:25 AM CDTFlash Flood WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard2 hr
May 5, 9:23 AM CDTSpecial Marine WarningLIX67 min
May 5, 10:25 AM CDTSpecial Marine WarningLIX50 min
May 5, 10:31 AM CDTSpecial Marine WarningLIX59 min
May 5, 11:11 AM CDTSpecial Marine WarningLIX49 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.