Alert archive / Texas / Tornado Watches in 2018

Tornado Watch 414

October 13, 201813 counties in Texas

The Storm Prediction Center issued this tornado watch at Oct 13, 2018, 3:06 PM CDT for 13 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Oct 13, 2018, 3:06 PM CDT (20:06 UTC)
Expired
Oct 13, 2018, 8:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
55 kt

Counties Angelina County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Houston County, TX, Madison County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Trinity County, TX

The radar

The Shreveport radar (KSHV), 157 km from the middle of the area, began a volume at 20:10 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
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
40%

Warnings issued inside it

10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Oct 13, 3:21 PM CDTTornado WarningSHVCherokee, Smith54 min
Oct 13, 4:12 PM CDTSevere Thunderstorm WarningSHVCherokee, Rusk, Smith63 min
Oct 13, 5:07 PM CDTTornado WarningSHVPanola, Rusk38 min
Oct 13, 5:11 PM CDTSevere Thunderstorm WarningSHVCherokee, Gregg, Rusk, Smith29 min
Oct 13, 5:29 PM CDTTornado WarningSHVPanola46 min
Oct 13, 6:07 PM CDTSevere Thunderstorm WarningHGXHouston38 min
Oct 13, 6:13 PM CDTTornado WarningSHVPanola7 min
Oct 13, 6:43 PM CDTSevere Thunderstorm WarningSHVPanola19 min
Oct 13, 7:28 PM CDTSevere Thunderstorm WarningSHVNacogdoches16 min
Oct 13, 7:33 PM CDTTornado WarningSHVNacogdoches12 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 12:00Z, 8.1 hours before the alert went out and 166 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-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2018-10-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2018-10-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 149 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
988 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
149 m²/s²
0-3 km storm-relative helicity
208 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

687 
WWUS20 KWNS 132004
SEL4  
SPC WW 132004
TXZ000-140100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 414
NWS Storm Prediction Center Norman OK
305 PM CDT Sat Oct 13 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Eastern Texas

* Effective this Saturday afternoon and evening from 305 PM until
  800 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 65 mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...A couple of longer-lived supercells may continue east
across parts of east-central Texas through early evening. All
hazards are possible before the tornado risk diminishes later this
evening.

The tornado watch area is approximately along and 50 statute miles
east and west of a line from 30 miles west southwest of Lufkin TX to
15 miles north northwest of Longview TX. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU4).

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 413...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 25025.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 12, 7:22 PM CDTMesoscale DiscussionSPCCrane, Crockett, Ector, Glasscock, Irion, Jeff Davis and 9 more2 hr
Oct 12, 8:14 PM CDTSevere Thunderstorm WatchSPCAndrews, Brewster, Crane, Culberson, Ector, Glasscock and 13 more8 hr
Oct 12, 10:58 PM CDTMesoscale DiscussionSPCCrane, Ector, Glasscock, Loving, Midland, Pecos and 6 more2 hr
Oct 13, 1:40 AM CDTMesoscale DiscussionSPCConcho, Crane, Crockett, Ector, Gillespie, Glasscock and 16 more65 min
Oct 13, 1:59 AM CDTSevere Thunderstorm WatchSPCConcho, Crockett, Irion, Kimble, McCulloch, Mason and 5 more6 hr
Oct 13, 7:40 AM CDTTornado WatchSPCBrown, Coleman, Concho, McCulloch, Menard, Runnels and 3 more4 hr
Oct 13, 7:47 AM CDTMesoscale DiscussionSPCBell, Bosque, Brown, Burnet, Coleman, Comanche and 13 more118 min
Oct 13, 9:54 AM CDTTornado WatchSPCAnderson, Bell, Bosque, Burnet, Comanche, Coryell and 22 more9 hr
Oct 13, 11:04 AM CDTMesoscale DiscussionSPCAnderson, Bell, Bosque, Brown, Burnet, Comanche and 27 more116 min
Oct 13, 1:56 PM CDTMesoscale DiscussionSPCAnderson, Bell, Brazos, Burleson, Burnet, Cherokee and 23 more2 hr
Oct 13, 5:34 PM CDTMesoscale DiscussionSPCAnderson, Bell, Falls, Freestone, Leon, Milam and 1 more56 min
Oct 13, 6:41 PM CDTMesoscale DiscussionSPCAngelina, Harrison, Houston, Madison, Nacogdoches, Panola and 4 more94 min

Nearby

Tornado Watches in Texas, 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.