Alert archive / Louisiana / Tornado Watches in 2024
Tornado Watch 667
The Storm Prediction Center issued this tornado watch at Sep 11, 2024, 12:43 PM CDT for 19 parishes in Louisiana; 4 counties in Mississippi. It was in force for 10 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 11, 2024, 12:43 PM CDT (17:43 UTC)
- Expired
- Sep 11, 2024, 11:00 PM CDT
- In force
- 10 hr
- Issued by
- the Storm Prediction Center
- Strongest gust expected
- 60 kt
All 23 counties
Ascension Parish, LA, Assumption Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS
The radar
The Hammond radar (KHDC), 79 km from the middle of the area, began a volume at 17:41 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 80%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 5%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 20%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 11, 3:01 PM CDT | Flash Flood Warning | LCH | St. Mary | 10 hr |
| Sep 11, 4:06 PM CDT | Flash Flood Warning | LIX | Terrebonne | 5 hr |
| Sep 11, 5:02 PM CDT | Flash Flood Warning | LIX | Lafourche, Terrebonne | 4 hr |
| Sep 11, 5:41 PM CDT | Flash Flood Warning | LCH | Saint Martin | 3 hr |
| Sep 11, 6:18 PM CDT | Flash Flood Warning | LIX | Assumption, Lafourche, Saint Charles, Saint James, Saint John the Baptist | 3 hr |
| Sep 11, 6:31 PM CDT | Flash Flood Warning | LIX | Jefferson, Orleans, Plaquemines, Saint Charles | 3 hr |
| Sep 11, 6:39 PM CDT | Flash Flood Warning | LIX | Saint Charles, Saint John the Baptist | 3 hr |
| Sep 11, 6:47 PM CDT | Flash Flood Warning | LIX | Ascension, Assumption, Iberville, Saint James, Saint John the Baptist | 6 hr |
| Sep 11, 7:19 PM CDT | Tornado Warning | LIX | Saint Tammany | 26 min |
| Sep 11, 7:48 PM CDT | Tornado Warning | LIX | Hancock | 27 min |
| Sep 11, 7:51 PM CDT | Flash Flood Warning | LIX | Livingston, Saint Tammany, Tangipahoa | 7 hr |
| Sep 11, 8:39 PM CDT | Flash Flood Warning | LIX | Jefferson, Orleans, Saint Charles, Saint John the Baptist | 9 hr |
| Sep 11, 8:56 PM CDT | Flash Flood Warning | LCH | Iberia, Saint Martin, St. Mary | 4 hr |
| Sep 11, 10:42 PM CDT | Flash Flood Warning | LIX | Harrison, Jackson | 3 hr |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Slidell Radar S, LA (KSIL), launched 12:00Z, 5.7 hours before the alert went out and 78 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.
- Mixed-layer CAPE
- 356 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 625 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- 122 m²/s²
- 0-3 km storm-relative helicity
- 143 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 11, 7:19 AM CDT | Mesoscale Discussion | SPC | Terrebonne | 3 hr |
| Sep 11, 12:28 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Iberia, Iberville, Jefferson, Lafourche and 12 more | 92 min |
| Sep 11, 3:23 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Iberia, Jefferson, Lafourche, Orleans and 8 more | 97 min |
Nearby
Tornado Watches in Louisiana, 2024Tornado Watches in Mississippi, 2024Every tornado watch in 2024
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; radar from the NEXRAD Level II archive.