Alert archive / Louisiana / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 111
The Storm Prediction Center issued this severe thunderstorm watch at Apr 25, 2015, 10:41 AM CDT for 22 parishes in Louisiana; 21 counties in Mississippi. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 25, 2015, 10:41 AM CDT (15:41 UTC)
- Expired
- Apr 25, 2015, 6:00 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 43 counties
Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS, Wilkinson County, MS
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 25, 10:58 AM CDT | Severe Thunderstorm Warning | LIX | Iberville, Pointe Coupee, West Baton Rouge | 19 min |
| Apr 25, 12:12 PM CDT | Severe Thunderstorm Warning | LIX | Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa | 33 min |
| Apr 25, 12:34 PM CDT | Severe Thunderstorm Warning | LIX | Saint Tammany | 26 min |
| Apr 25, 12:48 PM CDT | Severe Thunderstorm Warning | LIX | Ascension, Lafourche, Livingston, Saint Charles, Saint James, Saint John the Baptist and 1 more | 27 min |
| Apr 25, 1:11 PM CDT | Severe Thunderstorm Warning | LIX | Hancock, Harrison, Pearl River | 34 min |
| Apr 25, 1:17 PM CDT | Severe Thunderstorm Warning | LIX | Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles, Saint John the Baptist and 2 more | 28 min |
| Apr 25, 1:22 PM CDT | Severe Thunderstorm Warning | MOB | Stone | 65 min |
| Apr 25, 1:28 PM CDT | Severe Thunderstorm Warning | MOB | Greene | 62 min |
| Apr 25, 1:46 PM CDT | Severe Thunderstorm Warning | LIX | Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Tammany | 44 min |
| Apr 25, 2:09 PM CDT | Severe Thunderstorm Warning | LIX | Jackson | 21 min |
| Apr 25, 2:11 PM CDT | Severe Thunderstorm Warning | LIX | Saint Bernard | 22 min |
| Apr 25, 2:29 PM CDT | Severe Thunderstorm Warning | LIX | Harrison, Jackson | 31 min |
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, 3.7 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
- 1826 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 565 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 69 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 4.6
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 24, 7:46 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 7 more | 89 min |
| Apr 24, 9:20 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more | 55 min |
| Apr 24, 9:59 PM CDT | Tornado Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 14 more | 4 hr |
| Apr 24, 11:45 PM CDT | Mesoscale Discussion | SPC | Caldwell, East Carroll, Franklin, Jackson, Madison, Morehouse and 5 more | 90 min |
| Apr 25, 2:07 AM CDT | Mesoscale Discussion | SPC | Madison | 83 min |
| Apr 25, 7:12 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more | 6 hr |
| Apr 25, 9:35 AM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Avoyelles, Cameron, East Baton Rouge and 27 more | 115 min |
| Apr 25, 1:50 PM CDT | Mesoscale Discussion | SPC | Orleans, Saint Bernard, Saint Charles, Saint John the Baptist, Saint Tammany, Washington | 85 min |
| Apr 25, 12:50 AM CDT | Tornado Watch | SPC | Attala, Calhoun, Carroll, Chickasaw, Choctaw, Claiborne and 25 more | 6 hr |
| Apr 25, 4:12 AM CDT | Mesoscale Discussion | SPC | Clarke, George, Greene, Wayne | 63 min |
Nearby
Severe Thunderstorm Watches in Louisiana, 2015Severe Thunderstorm Watches in Mississippi, 2015Every severe thunderstorm watch in 2015
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.