Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 68, NWS New Orleans, LA

July 5, 20214 parishes in Louisiana

NWS New Orleans, LA issued this flash flood warning at Jul 5, 2021, 4:38 AM CDT for 4 parishes in Louisiana. It was in force for 88 min. 2 reports 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: Jul 5, 2021, 4:38 AM CDT (09:38 UTC)
Expired: Jul 5, 2021, 6:06 AM CDT
In force: 88 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

What was reported inside it

Time	Report	Where	Remark
Jul 5, 4:40 AM CDT	FLASH FLOOD	1 E Chalmette, LA	STREET/ROAD CLOSED DUE TO FLOODING.
Jul 5, 4:42 AM CDT	FLASH FLOOD	2 E Terrytown, LA	STREET/ROAD CLOSED DUE TO FLOODING.

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 00:00Z, 9.6 hours before the alert went out and 44 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2192 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 667 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

934 
WGUS54 KLIX 050938
FFWLIX
LAC051-071-075-087-051245-
/O.NEW.KLIX.FF.W.0068.210705T0938Z-210705T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
438 AM CDT Mon Jul 5 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Northwestern 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 745 AM CDT.

* At 438 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 2 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...
  New Orleans, Harvey, Timberlane, Marrero, Chalmette, Belle Chasse, 
  Metairie, Avondale, Jefferson, Gretna, Harahan, Westwego, 
  Terrytown, Arabi, Woodmere, Bridge City, Estelle, Elmwood, Meraux 
  and River Ridge.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 224 and 247.
	Interstate 510 between mile markers 2 and 3.
	Interstate 610 between mile markers 1 and 4.

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 2985 9023 3003 9024 3002 9014 3003 9009
      3003 9008 3003 9006 3003 9003 3004 9003
      3004 9001 3007 8994 3004 8994 3004 8990
      2986 8989

FLASH FLOOD...RADAR INDICATED

$$

TE

1 follow-up statement

918 
WGUS74 KLIX 051106
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
606 AM CDT Mon Jul 5 2021

LAC051-071-075-087-051116-
/O.CAN.KLIX.FF.W.0068.000000T0000Z-210705T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson LA-Orleans LA-Plaquemines LA-St. Bernard LA-
606 AM CDT Mon Jul 5 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN JEFFERSON, 
SOUTHWESTERN ORLEANS, NORTHWESTERN PLAQUEMINES AND WEST CENTRAL ST. 
BERNARD PARISHES...

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

LAT...LON 2985 9023 3003 9024 3002 9014 3003 9009
      3003 9008 3003 9006 3003 9003 3004 9003
      3004 9001 3007 8994 3004 8994 3004 8990
      2986 8989

$$

TE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 5, 4:43 AM CDT	Areal Flood Advisory	LIX	Saint Charles	86 min
Jul 5, 6:48 AM CDT	Areal Flood Advisory	LIX	Lafourche, Terrebonne	61 min
Jul 5, 3:15 PM CDT	Areal Flood Advisory	LIX	Jefferson, Saint Charles	89 min

Nearby

Flash Flood Warnings in Louisiana, 2021 Every 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.