Alert archive / Louisiana / Tornado Watches in 2018
Tornado Watch 418
The Storm Prediction Center issued this tornado watch at Oct 31, 2018, 8:14 PM CDT for Ashley County, Chicot County, Union County, Arkansas; 36 parishes in Louisiana. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 31, 2018, 8:14 PM CDT (01:14 UTC)
- Expired
- Nov 1, 2018, 4:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 39 counties
Ashley County, AR, Chicot County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA
The radar
The Ft Polk radar (KPOE), 115 km from the middle of the area, began a volume at 01:15 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
- 60%
- One or more EF2 to EF5 tornadoes
- 30%
- Ten or more severe wind reports
- 60%
- One or more gusts of 65 knots or more
- 20%
- 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
- 90%
Warnings issued inside it
44 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 31, 8:15 PM CDT | Tornado Warning | LCH | Beauregard | 26 min |
| Oct 31, 8:36 PM CDT | Severe Thunderstorm Warning | SHV | Bienville, Bossier, Caddo, Claiborne, De Soto, Red River and 2 more | 54 min |
| Oct 31, 8:40 PM CDT | Severe Thunderstorm Warning | LCH | Beauregard, Calcasieu, Vernon | 65 min |
| Oct 31, 8:44 PM CDT | Tornado Warning | LCH | Beauregard | 31 min |
| Oct 31, 9:41 PM CDT | Severe Thunderstorm Warning | LCH | Allen, Beauregard, Rapides, Vernon | 49 min |
| Oct 31, 9:43 PM CDT | Tornado Warning | LCH | Beauregard | 17 min |
| Oct 31, 10:28 PM CDT | Severe Thunderstorm Warning | LCH | Rapides, Vernon | 62 min |
| Oct 31, 10:38 PM CDT | Tornado Warning | LCH | Rapides | 25 min |
| Oct 31, 11:08 PM CDT | Tornado Warning | LCH | Rapides | 37 min |
| Oct 31, 11:29 PM CDT | Severe Thunderstorm Warning | LCH | Rapides | 27 min |
| Oct 31, 11:29 PM CDT | Severe Thunderstorm Warning | LCH | Calcasieu | 61 min |
| Oct 31, 11:35 PM CDT | Severe Thunderstorm Warning | JAN | Ashley | 40 min |
| Oct 31, 11:36 PM CDT | Tornado Warning | LCH | Rapides | 24 min |
| Oct 31, 11:45 PM CDT | Tornado Warning | JAN | Ashley | 45 min |
| Oct 31, 11:48 PM CDT | Tornado Warning | LCH | Allen, Beauregard, Evangeline, Rapides, Vernon | 27 min |
| Oct 31, 11:51 PM CDT | Tornado Warning | SHV | Grant, LaSalle | 39 min |
| Oct 31, 11:56 PM CDT | Tornado Warning | LCH | Calcasieu | 34 min |
| Oct 31, 11:57 PM CDT | Tornado Warning | LCH | Calcasieu, Cameron | 48 min |
| Nov 1, 12:09 AM CDT | Severe Thunderstorm Warning | LCH | Allen, Avoyelles, Evangeline, Rapides, Saint Landry, Vernon | 66 min |
| Nov 1, 12:13 AM CDT | Severe Thunderstorm Warning | JAN | Ashley, Chicot | 47 min |
| Nov 1, 12:14 AM CDT | Tornado Warning | LCH | Evangeline, Rapides | 31 min |
| Nov 1, 12:21 AM CDT | Severe Thunderstorm Warning | SHV | Grant, LaSalle | 54 min |
| Nov 1, 12:24 AM CDT | Tornado Warning | JAN | Ashley, Chicot | 36 min |
| Nov 1, 12:24 AM CDT | Tornado Warning | LCH | Avoyelles, Evangeline, Rapides | 24 min |
| Nov 1, 12:25 AM CDT | Tornado Warning | SHV | Caldwell, LaSalle | 41 min |
| Nov 1, 12:27 AM CDT | Tornado Warning | LCH | Calcasieu, Jefferson Davis | 22 min |
| Nov 1, 12:31 AM CDT | Severe Thunderstorm Warning | LCH | Calcasieu, Cameron, Jefferson Davis | 44 min |
| Nov 1, 12:31 AM CDT | Tornado Warning | LCH | Rapides | 15 min |
| Nov 1, 12:32 AM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Franklin | 58 min |
| Nov 1, 12:37 AM CDT | Tornado Warning | JAN | Catahoula, Franklin | 53 min |
| Nov 1, 12:48 AM CDT | Severe Thunderstorm Warning | LCH | Acadia, Evangeline, Jefferson Davis, Saint Landry | 42 min |
| Nov 1, 12:56 AM CDT | Tornado Warning | LCH | Avoyelles | 34 min |
| Nov 1, 12:59 AM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Concordia | 61 min |
| Nov 1, 12:59 AM CDT | Severe Thunderstorm Warning | LCH | Avoyelles, Evangeline, Rapides, Saint Landry | 61 min |
| Nov 1, 1:08 AM CDT | Severe Thunderstorm Warning | LCH | Cameron, Lafayette, Vermilion | 52 min |
| Nov 1, 1:11 AM CDT | Tornado Warning | JAN | Catahoula, Concordia | 64 min |
| Nov 1, 1:19 AM CDT | Tornado Warning | JAN | Catahoula, Concordia, Franklin, Tensas | 42 min |
| Nov 1, 1:22 AM CDT | Tornado Warning | LCH | Avoyelles | 12 min |
| Nov 1, 1:30 AM CDT | Severe Thunderstorm Warning | JAN | Concordia, Tensas | 90 min |
| Nov 1, 1:31 AM CDT | Severe Thunderstorm Warning | LIX | Pointe Coupee, West Feliciana | 59 min |
| Nov 1, 1:42 AM CDT | Severe Thunderstorm Warning | JAN | East Carroll, Madison | 63 min |
| Nov 1, 1:44 AM CDT | Tornado Warning | JAN | Madison, Tensas | 46 min |
| Nov 1, 1:53 AM CDT | Tornado Warning | JAN | Concordia | 42 min |
| Nov 1, 2:00 AM CDT | Tornado Warning | JAN | East Carroll | 45 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
Shreveport, LA (KBAD), launched 00:00Z, 1.2 hours before the alert went out and 152 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
- 985 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 741 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 213 m²/s²
- 0-3 km storm-relative helicity
- 311 m²/s²
- Significant tornado parameter
- 1.2
- Supercell composite
- 5.5
The text
As transmitted.
821 WWUS20 KWNS 010111 SEL8 SPC WW 010111 ARZ000-LAZ000-MSZ000-CWZ000-010900- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 418 NWS Storm Prediction Center Norman OK 810 PM CDT Wed Oct 31 2018 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern Arkansas Louisiana Western Mississippi Coastal Waters * Effective this Wednesday night and Thursday morning from 810 PM until 400 AM CDT. * Primary threats include... A few tornadoes likely with a couple intense tornadoes possible Scattered damaging wind gusts to 70 mph likely Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Conditions will continue to become increasingly favorable for supercells and bowing segments along and ahead an east/northeastward-moving convective line. Very strong low-level shear coincident with a moist air mass will support the possibility of damaging winds and tornadoes, a couple of which could be strong. The tornado watch area is approximately along and 60 statute miles east and west of a line from 40 miles east northeast of El Dorado AR to 30 miles southeast of Lake Charles LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 416...WW 417... 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 500. Mean storm motion vector 24035. ...Guyer
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 31, 11:07 PM CDT | Tornado Watch | SPC | Phillips | 9 hr |
| Oct 31, 11:52 PM CDT | Mesoscale Discussion | SPC | Ashley, Chicot, Columbia, Union | 53 min |
| Nov 1, 1:19 AM CDT | Mesoscale Discussion | SPC | Chicot | 116 min |
| Nov 1, 1:41 AM CDT | Mesoscale Discussion | SPC | Crittenden, Lee, Mississippi, St. Francis | 3 hr |
| Oct 31, 7:28 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 20 more | 92 min |
| Oct 31, 10:01 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 9 more | 89 min |
| Nov 1, 4:30 AM CDT | Mesoscale Discussion | SPC | Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 5 more | 2 hr |
Nearby
Tornado Watches in Louisiana, 2018Tornado Watches in Arkansas, 2018Every tornado watch in 2018
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.