Alert archive / Louisiana / Tornado Watches in 2017
Tornado Watch 180
The Storm Prediction Center issued this tornado watch at Apr 30, 2017, 1:49 AM CDT for Ashley County, Chicot County, Arkansas; 27 parishes in Louisiana; 9 counties in Mississippi. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 30, 2017, 1:49 AM CDT (06:49 UTC)
- Expired
- Apr 30, 2017, 9:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 38 counties
Ashley County, AR, Chicot County, AR, Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Claiborne County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS
The radar
The Ft Polk radar (KPOE), 70 km from the middle of the area, began a volume at 06:52 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
- 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
- 70%
Warnings issued inside it
31 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 30, 2:34 AM CDT | Severe Thunderstorm Warning | LCH | Acadia, Evangeline, Saint Landry | 41 min |
| Apr 30, 2:54 AM CDT | Severe Thunderstorm Warning | LCH | Acadia, Jefferson Davis | 21 min |
| Apr 30, 3:13 AM CDT | Flash Flood Warning | LCH | Acadia, Allen, Avoyelles, Calcasieu, Evangeline, Jefferson Davis and 1 more | 5 hr |
| Apr 30, 3:42 AM CDT | Severe Thunderstorm Warning | LCH | Acadia, Avoyelles, Evangeline, Saint Landry | 63 min |
| Apr 30, 4:34 AM CDT | Tornado Warning | JAN | Morehouse, Richland, West Carroll | 56 min |
| Apr 30, 4:40 AM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Concordia | 50 min |
| Apr 30, 5:06 AM CDT | Severe Thunderstorm Warning | LIX | Iberville, Pointe Coupee, West Baton Rouge, West Feliciana | 39 min |
| Apr 30, 5:29 AM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Concordia | 61 min |
| Apr 30, 5:45 AM CDT | Severe Thunderstorm Warning | LIX | Pointe Coupee, West Feliciana | 45 min |
| Apr 30, 5:47 AM CDT | Severe Thunderstorm Warning | JAN | Tensas | 58 min |
| Apr 30, 6:10 AM CDT | Flash Flood Warning | JAN | Concordia | 4 hr |
| Apr 30, 6:10 AM CDT | Flash Flood Warning | LCH | Avoyelles, Rapides | 4 hr |
| Apr 30, 6:14 AM CDT | Tornado Warning | JAN | Concordia | 34 min |
| Apr 30, 6:34 AM CDT | Severe Thunderstorm Warning | JAN | Madison, Tensas | 56 min |
| Apr 30, 6:35 AM CDT | Severe Thunderstorm Warning | LCH | Acadia, Avoyelles, Cameron, Evangeline, Lafayette, Saint Landry and 1 more | 55 min |
| Apr 30, 6:37 AM CDT | Severe Thunderstorm Warning | LIX | East Feliciana, Pointe Coupee, West Feliciana | 38 min |
| Apr 30, 6:41 AM CDT | Severe Thunderstorm Warning | JAN | Claiborne, Jefferson | 49 min |
| Apr 30, 6:43 AM CDT | Tornado Warning | JAN | Madison, Tensas | 62 min |
| Apr 30, 6:50 AM CDT | Severe Thunderstorm Warning | JAN | Adams, Franklin, Jefferson | 55 min |
| Apr 30, 7:04 AM CDT | Severe Thunderstorm Warning | LCH | Iberia, Lafayette, Saint Landry, Saint Martin, St. Mary, Vermilion | 71 min |
| Apr 30, 7:20 AM CDT | Tornado Warning | JAN | Issaquena, Sharkey, Warren, Yazoo | 55 min |
| Apr 30, 7:21 AM CDT | Tornado Warning | JAN | Claiborne, Copiah, Jefferson | 39 min |
| Apr 30, 7:28 AM CDT | Tornado Warning | JAN | Claiborne, Hinds, Warren | 62 min |
| Apr 30, 7:30 AM CDT | Severe Thunderstorm Warning | LIX | East Baton Rouge, East Feliciana, Iberville, Pointe Coupee, West Baton Rouge, West Feliciana | 30 min |
| Apr 30, 7:35 AM CDT | Severe Thunderstorm Warning | JAN | Copiah, Franklin, Lincoln | 40 min |
| Apr 30, 7:56 AM CDT | Severe Thunderstorm Warning | LIX | Amite, Wilkinson | 34 min |
| Apr 30, 8:12 AM CDT | Flash Flood Warning | JAN | Franklin, Lincoln | 3 hr |
| Apr 30, 8:13 AM CDT | Tornado Warning | JAN | Hinds, Madison, Warren, Yazoo | 62 min |
| Apr 30, 8:19 AM CDT | Severe Thunderstorm Warning | LCH | Iberia, Saint Martin, St. Mary | 41 min |
| Apr 30, 8:58 AM CDT | Severe Thunderstorm Warning | LCH | Saint Martin, St. Mary | 47 min |
| Apr 30, 9:00 AM CDT | Flash Flood Warning | JAN | Humphreys, Issaquena, Sharkey, Warren, Yazoo | 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
Lake Charles Mun, LA (KLCH), launched 00:00Z, 6.8 hours before the alert went out and 140 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
- 3254 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 602 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 198 m²/s²
- 0-3 km storm-relative helicity
- 251 m²/s²
- Significant tornado parameter
- 3.4
- Supercell composite
- 26.7
The text
As transmitted.
646 WWUS20 KWNS 300646 SEL0 SPC WW 300646 ARZ000-LAZ000-MSZ000-CWZ000-301400- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 180 NWS Storm Prediction Center Norman OK 150 AM CDT Sun Apr 30 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Arkansas Southern and eastern Louisiana Western Mississippi Coastal Waters * Effective this Sunday morning from 150 AM until 900 AM CDT. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Multiple corridors of intensifying thunderstorms are expected overnight ahead of a cold front. A very moist environment and strong deep-layer/low-level winds will support the possibility of a couple of tornadoes aside from a more prevalent damaging wind risk and some hail. The tornado watch area is approximately along and 60 statute miles east and west of a line from 35 miles west southwest of Intracoastal City LA to 75 miles northeast of Monroe LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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. && OTHER WATCH INFORMATION...CONTINUE...WW 178...WW 179... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 24035. ...Guyer
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 29, 9:38 PM CDT | Mesoscale Discussion | SPC | Clark, Columbia, Hempstead, Hot Spring, Howard, Lafayette and 5 more | 67 min |
| Apr 29, 10:23 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 36 more | 8 hr |
| Apr 29, 11:37 PM CDT | Mesoscale Discussion | SPC | Bradley, Calhoun, Clark, Cleveland, Columbia, Conway and 23 more | 53 min |
| Apr 30, 12:54 AM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clay and 26 more | 96 min |
| Apr 30, 1:10 AM CDT | Severe Thunderstorm Watch | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more | 6 hr |
| Apr 30, 2:58 AM CDT | Mesoscale Discussion | SPC | Crittenden, Cross, Lee, Mississippi, Phillips, Poinsett and 1 more | 92 min |
| Apr 30, 3:36 AM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Cleveland, Desha, Drew and 10 more | 84 min |
| Apr 30, 5:41 AM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Clay, Cleveland, Craighead, Crittenden and 19 more | 64 min |
| Apr 30, 6:12 AM CDT | Mesoscale Discussion | SPC | Ashley, Chicot | 93 min |
| Apr 30, 1:14 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 20 more | 91 min |
| Apr 30, 6:59 AM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Jefferson, Lafourche and 12 more | 2 hr |
| Apr 30, 7:32 AM CDT | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 14 more | 7 hr |
| Apr 30, 10:06 AM CDT | Mesoscale Discussion | SPC | Chickasaw, Itawamba, Lee, Monroe, Pontotoc, Prentiss and 2 more | 84 min |
| Apr 30, 10:36 AM CDT | Tornado Watch | SPC | Alcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 9 more | 8 hr |
Nearby
Tornado Watches in Louisiana, 2017Tornado Watches in Mississippi, 2017Tornado Watches in Arkansas, 2017Every tornado 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; radar from the NEXRAD Level II archive.