Alert archive / Texas / Tornado Warnings in 2018

Tornado Warning 21, NWS Shreveport, LA

March 18, 2018San Augustine County, Shelby County, Texas

NWS Shreveport, LA issued this tornado warning at Mar 18, 2018, 8:37 PM CDT for San Augustine County, Shelby County, Texas. It was in force for 26 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: Mar 18, 2018, 8:37 PM CDT (01:37 UTC)
Expired: Mar 18, 2018, 9:03 PM CDT
In force: 26 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.5 in

Counties San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 105 km from the middle of the area, began a volume at 01:41 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
Mar 18, 4:06 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 1.6 hours before the alert went out and 111 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: 1160 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 810 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 222 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 3.8

Open this sounding in Storm Lab

The text

As transmitted.

415 
WFUS54 KSHV 190137
TORSHV
TXC405-419-190215-
/O.NEW.KSHV.TO.W.0021.180319T0137Z-180319T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Shreveport LA
837 PM CDT SUN MAR 18 2018

The National Weather Service in Shreveport has issued a

* Tornado Warning for...
  South central Shelby County in eastern Texas...
  Northeastern San Augustine County in eastern Texas...

* Until 915 PM CDT
    
* At 836 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 9 miles west of Bland Lake, or 17 miles south of
  Center, moving east at 20 mph.

  HAZARD...Tornado and ping pong ball size hail. 

  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...
  San Augustine and Bland Lake around 905 PM CDT. 

Other locations impacted by this tornadic thunderstorm include
Calgary and Denning.

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 3149 9427 3157 9428 3167 9407 3152 9403
TIME...MOT...LOC 0136Z 249DEG 16KT 3156 9427 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

35

2 follow-up statements

075 
WWUS54 KSHV 190158 RRA
SVSSHV

Severe Weather Statement
National Weather Service Shreveport LA
858 PM CDT SUN MAR 18 2018

TXC405-419-190215-
/O.CON.KSHV.TO.W.0021.000000T0000Z-180319T0215Z/
Shelby TX-San Augustine TX-
858 PM CDT SUN MAR 18 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 915 PM CDT FOR
SOUTHEASTERN SHELBY AND NORTHEASTERN SAN AUGUSTINE COUNTIES...
    
At 858 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Bland Lake, or 15 miles south of Center, moving east
at 25 mph.

HAZARD...Tornado and quarter size hail. 

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 tornadic thunderstorm will remain over mainly rural areas of
southeastern Shelby and northeastern San Augustine Counties,
including the following locations: Calgary.

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 3151 9413 3161 9416 3164 9406 3152 9403
TIME...MOT...LOC 0158Z 262DEG 21KT 3157 9411 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

35

223 
WWUS54 KSHV 190203
SVSSHV

Severe Weather Statement
National Weather Service Shreveport LA
903 PM CDT SUN MAR 18 2018

TXC405-419-190213-
/O.CAN.KSHV.TO.W.0021.000000T0000Z-180319T0215Z/
Shelby TX-San Augustine TX-
903 PM CDT SUN MAR 18 2018

...THE TORNADO WARNING FOR SOUTHEASTERN SHELBY AND NORTHEASTERN SAN
AUGUSTINE COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore the warning has been cancelled.

A severe thunderstorm watch remains in effect until 1100 PM CDT for
eastern Texas.

LAT...LON 3151 9413 3161 9416 3164 9406 3152 9403
TIME...MOT...LOC 0202Z 249DEG 16KT 3158 9408 

$$

35

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 18, 7:53 PM CDT	Special Weather Statement	SHV	Nacogdoches	52 min
Mar 18, 8:01 PM CDT	Severe Thunderstorm Warning	SHV	Nacogdoches, San Augustine, Shelby	59 min
Mar 18, 8:28 PM CDT	Tornado Warning	SHV	San Augustine, Shelby	18 min
Mar 18, 8:44 PM CDT	Severe Thunderstorm Warning	SHV	Panola, Shelby	46 min
Mar 18, 8:44 PM CDT	Severe Thunderstorm Warning	SHV	Angelina, Sabine, San Augustine	61 min
Mar 18, 9:22 PM CDT	Severe Thunderstorm Warning	SHV	Sabine	15 min
Mar 19, 4:30 AM CDT	Lake Wind Advisory	SHV	Angelina, Bowie, Camp, Cass, Cherokee, Franklin and 15 more	15 hr

Nearby

Tornado Warnings in Texas, 2018 Every tornado warning in 2018 Tornadoes 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.