Alert archive / Louisiana / Tornado Warnings in 2017

Tornado Warning 73, NWS Shreveport, LA

May 11, 2017Bossier Parish, Webster Parish, Louisiana; Lafayette County, Arkansas

NWS Shreveport, LA issued this tornado warning at May 11, 2017, 8:52 PM CDT for Bossier Parish, Webster Parish, Louisiana; Lafayette County, Arkansas. It was in force for 18 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 11, 2017, 8:52 PM CDT (01:52 UTC)
Expired: May 11, 2017, 9:10 PM CDT
In force: 18 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Lafayette County, AR, Bossier Parish, LA, Webster Parish, LA

The radar

The Shreveport radar (KSHV), 58 km from the middle of the area, began a volume at 01:55 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 11, 2:43 PM CDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 1.9 hours before the alert went out and 52 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1602 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 920 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 152 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 7.0

Open this sounding in Storm Lab

The text

As transmitted.

010 
WFUS54 KSHV 120152
TORSHV
ARC073-LAC015-119-120230-
/O.NEW.KSHV.TO.W.0073.170512T0152Z-170512T0230Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Shreveport LA
852 PM CDT THU MAY 11 2017

The National Weather Service in Shreveport has issued a

* Tornado Warning for...
  South central Lafayette County in southwestern Arkansas...
  Northwestern Webster Parish in northwestern Louisiana...
  North central Bossier Parish in northwestern Louisiana...

* Until 930 PM CDT
    
* At 852 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Plain Dealing, or 13 miles southwest of
  Springhill, moving northeast at 30 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* This dangerous storm will be near...
  Cullen around 915 PM CDT. 

Other locations impacted by this tornadic thunderstorm include
Bolinger.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3286 9368 3291 9373 3308 9360 3297 9345
TIME...MOT...LOC 0152Z 229DEG 26KT 3291 9366 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

13

2 follow-up statements

676 
WWUS54 KSHV 120200
SVSSHV

Severe Weather Statement
National Weather Service Shreveport LA
900 PM CDT THU MAY 11 2017

ARC073-LAC015-119-120230-
/O.CON.KSHV.TO.W.0073.000000T0000Z-170512T0230Z/
Lafayette AR-Webster LA-Bossier LA-
900 PM CDT THU MAY 11 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 930 PM CDT FOR SOUTH
CENTRAL LAFAYETTE COUNTY...NORTHWESTERN WEBSTER AND NORTH CENTRAL
BOSSIER PARISHES...
    
At 859 PM CDT, a severe thunderstorm capable of producing a tornado 
was located 5 miles northeast of Plain Dealing, or 10 miles 
southwest of Springhill, moving northeast at 30 mph.

HAZARD...Tornado. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

This dangerous storm will be near...
  Cullen around 915 PM CDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3291 9363 3294 9368 3308 9360 3297 9345
TIME...MOT...LOC 0159Z 227DEG 26KT 3294 9363 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

13

509 
WWUS54 KSHV 120210
SVSSHV

Severe Weather Statement
National Weather Service Shreveport LA
910 PM CDT THU MAY 11 2017

ARC073-LAC015-119-120220-
/O.CAN.KSHV.TO.W.0073.000000T0000Z-170512T0230Z/
Lafayette AR-Webster LA-Bossier LA-
910 PM CDT THU MAY 11 2017

...THE TORNADO WARNING FOR SOUTH CENTRAL LAFAYETTE COUNTY...
NORTHWESTERN WEBSTER AND NORTH CENTRAL BOSSIER PARISHES IS
CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

A severe thunderstorm watch remains in effect until 1000 PM CDT for
southwestern Arkansas...and northwestern Louisiana.

LAT...LON 3291 9363 3294 9368 3308 9360 3297 9345
TIME...MOT...LOC 0209Z 229DEG 26KT 3299 9356 

$$

13

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 8:11 PM CDT	Severe Thunderstorm Warning	SHV	Bossier, Caddo	64 min
May 11, 8:17 PM CDT	Tornado Warning	SHV	Bossier, Caddo	28 min
May 11, 9:17 PM CDT	Severe Thunderstorm Warning	SHV	De Soto, Sabine	43 min
May 12, 4:32 AM CDT	Lake Wind Advisory	SHV	Bossier, Caddo, De Soto, Sabine	13 hr
May 11, 7:24 PM CDT	Special Weather Statement	SHV	Hempstead	21 min
May 11, 7:47 PM CDT	Special Weather Statement	SHV	Nevada	13 min
May 12, 12:32 AM CDT	Special Weather Statement	SHV	Sevier	28 min
May 12, 1:00 AM CDT	Special Weather Statement	SHV	Sevier	30 min
May 12, 2:55 PM CDT	Special Weather Statement	SHV	Nevada	50 min

Nearby

Tornado Warnings in Louisiana, 2017 Tornado Warnings in Arkansas, 2017 Every tornado warning in 2017 Tornadoes 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.