Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 66, NWS New Orleans, LA

July 3, 2021Jefferson Parish, Orleans Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Jul 3, 2021, 2:25 PM CDT for Jefferson Parish, Orleans Parish, Louisiana. It was in force for 3 hr. 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: Jul 3, 2021, 2:25 PM CDT (19:25 UTC)
Expired: Jul 3, 2021, 5:30 PM CDT
In force: 3 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

Counties Jefferson Parish, LA, Orleans Parish, LA

What was reported inside it

Time	Report	Where	Remark
Jul 3, 2:40 PM CDT	FLASH FLOOD	New Orleans, LA	NWS EMPLOYEE REPORTS MULTIPLE FLOODED STREETS AT INTERSECTIONS AND BROAD STREET IS DOWN TO ONE LANE IN NEW ORLEANS NEAR MID CITY.

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, 7.4 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-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: 1029 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 609 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -50 m²/s²
0-3 km storm-relative helicity: -48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

834 
WGUS54 KLIX 031925
FFWLIX
LAC051-071-032230-
/O.NEW.KLIX.FF.W.0066.210703T1925Z-210703T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
225 PM CDT Sat Jul 3 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...

* Until 530 PM CDT.

* At 225 PM 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 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, Marrero, Harvey, Timberlane, Metairie, Jefferson, 
  Gretna, Westwego, Bridge City and Terrytown.

This includes the following Interstates...
	Interstate 10 in Louisiana between mile markers 229 and 238.
	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.

&&

LAT...LON 2988 9002 2988 9015 3002 9016 3002 9014
      3002 9013 3002 9006

FLASH FLOOD...RADAR INDICATED

$$

MW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 2, 7:15 PM CDT	Flash Flood Warning	LIX	Ascension, East Baton Rouge	3 hr
Jul 2, 7:48 PM CDT	Special Marine Warning	LIX		57 min
Jul 2, 7:56 PM CDT	Special Weather Statement	LIX	Saint Charles, Saint John the Baptist	34 min
Jul 2, 8:14 PM CDT	Areal Flood Advisory	LIX	East Baton Rouge	61 min
Jul 2, 8:56 PM CDT	Special Marine Warning	LIX		64 min
Jul 2, 9:52 PM CDT	Special Marine Warning	LIX		38 min
Jul 3, 1:23 PM CDT	Areal Flood Advisory	LIX	Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles	3 hr
Jul 3, 1:31 PM CDT	Flash Flood Warning	LIX	Jefferson, Orleans, Plaquemines, Saint Bernard	111 min
Jul 3, 1:48 PM CDT	Areal Flood Advisory	LIX	Ascension, East Baton Rouge, Iberville, Livingston	44 min
Jul 3, 3:02 PM CDT	Flash Flood Warning	LIX	Jefferson	3 hr
Jul 3, 4:39 PM CDT	Special Weather Statement	LIX	East Baton Rouge	36 min
Jul 3, 4:58 PM CDT	Special Weather Statement	LIX	East Baton Rouge	32 min
Jul 3, 5:10 PM CDT	Areal Flood Advisory	LIX	Ascension, East Baton Rouge, Iberville, Livingston, West Baton Rouge	3 hr

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.