Alert archive / Louisiana / Tornado Watches in 2015
Tornado Watch 99
The Storm Prediction Center issued this tornado watch at Apr 24, 2015, 12:18 PM CDT for 16 parishes in Louisiana; Jasper County, Newton County, Orange County, Texas. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 24, 2015, 12:18 PM CDT (17:18 UTC)
- Expired
- Apr 24, 2015, 4:48 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Jasper County, TX, Newton County, TX, Orange County, TX
The radar
The Lake Charles radar (KLCH), 48 km from the middle of the area, began a volume at 17:18 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 24, 12:18 PM CDT | Tornado Warning | LCH | Beauregard, Calcasieu | 27 min |
| Apr 24, 12:45 PM CDT | Tornado Warning | LCH | Allen, Beauregard, Calcasieu, Jefferson Davis | 30 min |
| Apr 24, 1:15 PM CDT | Severe Thunderstorm Warning | LCH | Acadia, Allen, Beauregard, Calcasieu, Evangeline, Jefferson Davis and 1 more | 45 min |
| Apr 24, 1:59 PM CDT | Severe Thunderstorm Warning | LCH | Acadia, Allen, Evangeline, Jefferson Davis, Lafayette, Saint Landry | 31 min |
| Apr 24, 2:30 PM CDT | Severe Thunderstorm Warning | LCH | Acadia, Lafayette, Saint Landry, Saint Martin | 30 min |
| Apr 24, 3:09 PM CDT | Severe Thunderstorm Warning | LCH | Lafayette, Saint Landry, Saint Martin | 51 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
Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.3 hours before the alert went out and 48 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
- 1123 J/kg
- Mixed-layer CIN
- -100 J/kg
- Mixed-layer LCL
- 692 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 111 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 4.2
The text
As transmitted, in the capitals the NWS used until 2016.
772 WWUS20 KWNS 241710 SEL9 SPC WW 241710 LAZ000-TXZ000-CWZ000-242300- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 99 NWS STORM PREDICTION CENTER NORMAN OK 1210 PM CDT FRI APR 24 2015 THE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF SOUTHWEST LOUISIANA FAR SOUTHEAST TEXAS COASTAL WATERS * EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1210 PM UNTIL 600 PM CDT. * PRIMARY THREATS INCLUDE... A COUPLE TORNADOES POSSIBLE SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE SUMMARY...INTENSIFYING THUNDERSTORM COMPLEX APPROACHING THE SABINE RIVER SHOULD TRACK EAST-SOUTHEAST ACROSS SOUTHWEST LOUISIANA THIS AFTERNOON. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES NORTHEAST OF FORT POLK LOUISIANA TO 25 MILES SOUTHWEST OF INTRACOASTAL CITY LOUISIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. && AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM MOTION VECTOR 29025. ...GRAMS/MEAD
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 24, 10:29 AM CDT | Mesoscale Discussion | SPC | Allen, Beauregard, Calcasieu, Jefferson Davis | 91 min |
| Apr 24, 11:53 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Assumption, Beauregard, Calcasieu, Cameron and 7 more | 97 min |
| Apr 24, 1:58 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Cameron, East Baton Rouge, Iberia and 15 more | 92 min |
| Apr 24, 3:15 PM CDT | Tornado Watch | SPC | Ascension, Assumption, Iberville, Jefferson, Lafourche, Orleans and 6 more | 5 hr |
| Apr 24, 3:58 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 15 more | 92 min |
| Apr 24, 4:45 PM CDT | Tornado Watch | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 7 more | 5 hr |
| Apr 23, 9:34 PM CDT | Mesoscale Discussion | SPC | Bandera, Dimmit, Edwards, Frio, Jim Hogg, Kinney and 10 more | 56 min |
| Apr 24, 2:36 AM CDT | Mesoscale Discussion | SPC | Dimmit, La Salle, McMullen, Webb, Zavala | 84 min |
| Apr 24, 3:01 AM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Dimmit, Frio, La Salle, Live Oak, McMullen and 5 more | 4 hr |
| Apr 24, 5:41 AM CDT | Mesoscale Discussion | SPC | Atascosa, Bandera, Dimmit, Duval, Edwards, Frio and 10 more | 94 min |
| Apr 24, 11:12 AM CDT | Mesoscale Discussion | SPC | Bosque, Brown, Callahan, Coke, Coleman, Collin and 43 more | 2 hr |
| Apr 24, 12:56 PM CDT | Mesoscale Discussion | SPC | Childress, Collingsworth, Cottle, Crosby, Dickens, Foard and 3 more | 94 min |
| Apr 24, 2:10 PM CDT | Tornado Watch | SPC | Anderson, Bell, Bosque, Brown, Callahan, Coke and 52 more | 8 hr |
| Apr 24, 4:56 PM CDT | Mesoscale Discussion | SPC | Atascosa, Dimmit, Duval, Frio, Jim Hogg, Kinney and 9 more | 94 min |
| Apr 24, 6:01 PM CDT | Mesoscale Discussion | SPC | Dallas, Ellis, Erath, Hood, Johnson, Kaufman and 3 more | 59 min |
| Apr 24, 6:53 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bee, Brooks, Cameron, DeWitt, Dimmit and 19 more | 6 hr |
Nearby
Tornado Watches in Louisiana, 2015Tornado Watches in Texas, 2015Every tornado 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; radar from the NEXRAD Level II archive.