Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 73, NWS New Orleans, LA

July 15, 2021Jefferson Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Jul 15, 2021, 12:48 PM CDT for Jefferson Parish, Louisiana. It was in force for 49 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
Jul 15, 2021, 12:48 PM CDT (17:48 UTC)
Expired
Jul 15, 2021, 1:37 PM CDT
In force
49 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

County Jefferson Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 5.8 hours before the alert went out and 51 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 2021-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2331 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 12:00Z on 2021-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 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
2331 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
619 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
-34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

105 
WGUS54 KLIX 151748
FFWLIX
LAC051-152100-
/O.NEW.KLIX.FF.W.0073.210715T1748Z-210715T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
1248 PM CDT Thu Jul 15 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  North Central Jefferson Parish in southeastern Louisiana...

* Until 400 PM CDT.

* At 1248 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts of 1 to 2 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...
  New Orleans and Metairie.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 227 and 230.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2997 9013 2998 9020 3002 9018 3002 9014
      3002 9013 3002 9012

FLASH FLOOD...RADAR INDICATED

$$

CAB
2 follow-up statements
168 
WGUS74 KLIX 151814
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
114 PM CDT Thu Jul 15 2021

LAC051-152100-
/O.CON.KLIX.FF.W.0073.000000T0000Z-210715T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-
114 PM CDT Thu Jul 15 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 PM CDT THIS 
AFTERNOON FOR NORTH CENTRAL JEFFERSON PARISH...

At 114 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1.5 and 3 inches of rain have 
fallen. Additional rainfall amounts of 0.5 to 0.8 inches are 
possible in the warned area. The rain is coming to an end but rapid 
runoff may still lead to some flash flooding.

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...
  New Orleans and Metairie.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 227 and 230.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2997 9013 2998 9020 3002 9018 3002 9014
      3002 9013 3002 9012

FLASH FLOOD...RADAR INDICATED

$$

CAB
288 
WGUS74 KLIX 151837
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
137 PM CDT Thu Jul 15 2021

LAC051-151847-
/O.CAN.KLIX.FF.W.0073.000000T0000Z-210715T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-
137 PM CDT Thu Jul 15 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL JEFFERSON 
PARISH...

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

LAT...LON 2997 9013 2998 9020 3002 9018 3002 9014
      3002 9013 3002 9012

$$

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 10:23 AM CDTSpecial Weather StatementLIXTerrebonne37 min
Jul 15, 11:40 AM CDTSpecial Weather StatementLIXIberville35 min
Jul 15, 11:42 AM CDTSpecial Weather StatementLIXJefferson63 min
Jul 15, 11:48 AM CDTSpecial Weather StatementLIXSaint James57 min
Jul 15, 12:21 PM CDTSpecial Weather StatementLIXSaint Charles54 min
Jul 15, 12:31 PM CDTAreal Flood AdvisoryLIXJefferson65 min
Jul 15, 12:45 PM CDTSpecial Weather StatementLIXWashington75 min
Jul 15, 12:53 PM CDTSpecial Weather StatementLIXSaint John the Baptist82 min
Jul 15, 1:11 PM CDTSpecial Weather StatementLIXOrleans79 min
Jul 15, 1:33 PM CDTSpecial Weather StatementLIXWest Feliciana57 min
Jul 15, 1:50 PM CDTSpecial Weather StatementLIXSaint Tammany55 min
Jul 15, 1:58 PM CDTSpecial Weather StatementLIXEast Baton Rouge62 min
Jul 15, 2:35 PM CDTSpecial Weather StatementLIXTangipahoa55 min
Jul 15, 2:47 PM CDTSpecial Weather StatementLIXSaint James58 min
Jul 15, 3:31 PM CDTSpecial Weather StatementLIXEast Feliciana29 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.