Alert archive / Louisiana / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 212
The Storm Prediction Center issued this severe thunderstorm watch at May 12, 2017, 10:35 AM CDT for 4 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 12, 2017, 10:35 AM CDT (15:35 UTC)
- Expired
- May 12, 2017, 4:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 55 kt
All 25 counties
Baldwin County, AL, Escambia County, AL, Mobile County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Assumption Parish, LA, Jefferson Parish, LA, Lafourche 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 Tammany Parish, LA, Terrebonne Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
20 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 10:40 AM CDT | Severe Thunderstorm Warning | LIX | Saint Charles | 35 min |
| May 12, 10:43 AM CDT | Tornado Warning | LIX | Jefferson, Saint Charles | 19 min |
| May 12, 10:45 AM CDT | Severe Thunderstorm Warning | MOB | George, Greene, Perry, Stone | 60 min |
| May 12, 11:00 AM CDT | Severe Thunderstorm Warning | LIX | Jefferson, Plaquemines | 45 min |
| May 12, 11:04 AM CDT | Tornado Warning | LIX | Jefferson, Plaquemines | 28 min |
| May 12, 11:10 AM CDT | Severe Thunderstorm Warning | LIX | Orleans, Saint Bernard | 65 min |
| May 12, 11:30 AM CDT | Severe Thunderstorm Warning | LIX | Orleans | 30 min |
| May 12, 11:41 AM CDT | Severe Thunderstorm Warning | MOB | George, Stone | 64 min |
| May 12, 11:45 AM CDT | Severe Thunderstorm Warning | LIX | Plaquemines, Saint Bernard | 45 min |
| May 12, 11:54 AM CDT | Tornado Warning | MOB | Stone | 10 min |
| May 12, 11:59 AM CDT | Severe Thunderstorm Warning | MOB | Mobile, Washington | 61 min |
| May 12, 12:34 PM CDT | Severe Thunderstorm Warning | MOB | Mobile | 56 min |
| May 12, 1:05 PM CDT | Severe Thunderstorm Warning | MOB | Baldwin | 40 min |
| May 12, 1:11 PM CDT | Severe Thunderstorm Warning | MOB | Escambia | 27 min |
| May 12, 1:16 PM CDT | Severe Thunderstorm Warning | MOB | Baldwin, Mobile | 44 min |
| May 12, 1:28 PM CDT | Severe Thunderstorm Warning | MOB | Mobile | 47 min |
| May 12, 1:43 PM CDT | Severe Thunderstorm Warning | MOB | Baldwin, Escambia | 47 min |
| May 12, 2:15 PM CDT | Severe Thunderstorm Warning | MOB | Conecuh, Covington, Escambia | 60 min |
| May 12, 2:35 PM CDT | Severe Thunderstorm Warning | MOB | Escambia, Okaloosa, Santa Rosa | 40 min |
| May 12, 3:00 PM CDT | Severe Thunderstorm Warning | MOB | Okaloosa, Santa Rosa | 60 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, 3.6 hours before the alert went out and 30 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
- 1224 J/kg
- Mixed-layer CIN
- -6 J/kg
- Mixed-layer LCL
- 587 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 118 m²/s²
- 0-3 km storm-relative helicity
- 136 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 9:56 AM CDT | Mesoscale Discussion | SPC | Washington | 3 hr |
| May 12, 10:56 AM CDT | Mesoscale Discussion | SPC | Bibb, Blount, Calhoun, Cherokee, Chilton, Clay and 16 more | 3 hr |
| May 12, 1:06 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Cullman and 7 more | 2 hr |
| May 12, 1:42 PM CDT | Mesoscale Discussion | SPC | Baldwin, Barbour, Butler, Coffee, Conecuh, Covington and 8 more | 108 min |
| May 12, 4:24 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 4 more | 3 hr |
| May 12, 10:59 AM CDT | Mesoscale Discussion | SPC | Morehouse, West Carroll | 3 hr |
| May 12, 1:43 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more | 3 hr |
Nearby
Severe Thunderstorm Watches in Louisiana, 2017Severe Thunderstorm Watches in Mississippi, 2017Severe Thunderstorm Watches in Alabama, 2017Every severe thunderstorm watch in 2017
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.