Alert archive / Texas / Tornado Watches in 2017

Tornado Watch 175

April 29, 201724 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 29, 2017, 5:10 PM CDT for 24 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 29, 2017, 5:10 PM CDT (22:10 UTC)
Expired
Apr 29, 2017, 10:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 24 counties

Anderson County, TX, Camp County, TX, Cherokee County, TX, Delta County, TX, Fannin County, TX, Franklin County, TX, Freestone County, TX, Henderson County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Leon County, TX, Limestone County, TX, Morris County, TX, Navarro County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 138 km from the middle of the area, began a volume at 22:13 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
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 29, 5:12 PM CDTSevere Thunderstorm WarningFWDDelta, Fannin, Hopkins, Hunt, Lamar, Rains48 min
Apr 29, 5:23 PM CDTSevere Thunderstorm WarningFWDEllis, Kaufman52 min
Apr 29, 5:23 PM CDTTornado WarningFWDHenderson, Van Zandt37 min
Apr 29, 5:31 PM CDTSevere Thunderstorm WarningFWDFannin, Hunt59 min
Apr 29, 5:33 PM CDTTornado WarningFWDHenderson27 min
Apr 29, 5:37 PM CDTTornado WarningFWDDelta, Hopkins, Hunt23 min
Apr 29, 5:45 PM CDTTornado Warning Tornado observedFWDVan Zandt30 min
Apr 29, 5:49 PM CDTSevere Thunderstorm WarningFWDHunt, Kaufman, Rains, Van Zandt56 min
Apr 29, 5:57 PM CDTSevere Thunderstorm WarningFWDEllis, Henderson, Kaufman, Navarro, Rockwall, Van Zandt63 min
Apr 29, 6:01 PM CDTSevere Thunderstorm WarningFWDCollin, Delta, Fannin, Hunt, Lamar, Rockwall59 min
Apr 29, 6:13 PM CDTTornado WarningFWDRains, Van Zandt47 min
Apr 29, 6:50 PM CDTTornado WarningFWDVan Zandt20 min
Apr 29, 6:54 PM CDTTornado WarningFWDRains, Van Zandt36 min
Apr 29, 7:04 PM CDTSevere Thunderstorm WarningFWDHenderson, Kaufman, Van Zandt56 min
Apr 29, 7:18 PM CDTTornado WarningFWDVan Zandt57 min
Apr 29, 7:20 PM CDTTornado WarningFWDHopkins55 min
Apr 29, 7:28 PM CDTTornado WarningSHVSmith, Wood32 min
Apr 29, 7:32 PM CDTSevere Thunderstorm WarningFWDRains, Van Zandt58 min
Apr 29, 7:38 PM CDTFlash Flood WarningFWDHenderson, Navarro3 hr
Apr 29, 7:44 PM CDTSevere Thunderstorm WarningFWDHopkins31 min
Apr 29, 7:47 PM CDTSevere Thunderstorm WarningSHVFranklin, Smith, Wood43 min
Apr 29, 7:49 PM CDTFlash Flood WarningFWDRains, Van Zandt3 hr
Apr 29, 7:58 PM CDTTornado WarningFWDVan Zandt32 min
Apr 29, 7:59 PM CDTSevere Thunderstorm WarningFWDDelta, Hopkins, Lamar30 min
Apr 29, 7:59 PM CDTSevere Thunderstorm WarningSHVFranklin, Red River, Titus, Wood33 min
Apr 29, 8:12 PM CDTSevere Thunderstorm WarningSHVSmith, Upshur, Wood63 min
Apr 29, 8:18 PM CDTSevere Thunderstorm WarningSHVFranklin, Morris, Red River, Titus57 min
Apr 29, 8:25 PM CDTSevere Thunderstorm WarningSHVSmith, Wood65 min
Apr 29, 8:26 PM CDTTornado WarningSHVSmith, Wood49 min
Apr 29, 8:35 PM CDTTornado WarningSHVSmith, Wood40 min
Apr 29, 9:15 PM CDTSevere Thunderstorm WarningSHVBowie, Camp, Franklin, Marion, Morris, Red River and 4 more44 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

Fort Worth, TX (KFWD), launched 12:00Z, 10.2 hours before the alert went out and 131 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, Fort Worth, TX at 12:00Z on 2017-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2666 joules per kilogram.LCLLFCEL10008507005003002001001 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, Fort Worth, TX at 12:00Z on 2017-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 353 square meters per square second.19395878Sfc1 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
2666 J/kg
Mixed-layer CIN
-137 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
353 m²/s²
0-3 km storm-relative helicity
528 m²/s²
Significant tornado parameter
1.8
Supercell composite
14.1

Open this sounding in Storm Lab

The text

As transmitted.

112 
WWUS20 KWNS 292206
SEL5  
SPC WW 292206
TXZ000-300300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 175
NWS Storm Prediction Center Norman OK
510 PM CDT Sat Apr 29 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northeast Texas

* Effective this Saturday afternoon and evening from 510 PM until
  1000 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated very large hail events to 2 inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...A band of storms ahead of a cold front and on the west
edge of an outflow boundary will be in a zone supportive of
supercells with the potential to produce a couple of tornadoes,
along with isolated large hail and damaging winds.

The tornado watch area is approximately along and 40 statute miles
east and west of a line from 15 miles northwest of Paris TX to 40
miles southeast of Corsicana TX. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU5).

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 174...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 22020.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 10:18 PM CDTMesoscale DiscussionSPCChildress, Collingsworth, Cottle, Foard, Hall, Hardeman and 2 more117 min
Apr 28, 10:35 PM CDTSevere Thunderstorm WatchSPCChildress, Collingsworth, Cottle, Dickens, Floyd, Foard and 6 more8 hr
Apr 29, 2:45 AM CDTMesoscale DiscussionSPCBriscoe, Childress, Collingsworth, Cottle, Crosby, Dickens and 8 more2 hr
Apr 29, 9:19 AM CDTMesoscale DiscussionSPCHardin, Jasper, Newton, Orange, Sabine, Tyler116 min
Apr 29, 2:10 PM CDTMesoscale DiscussionSPCCollin, Dallas, Denton, Ellis, Fannin, Grayson and 6 more2 hr
Apr 29, 6:31 PM CDTMesoscale DiscussionSPCBastrop, Caldwell, Falls, Lee, Milam, Travis and 1 more59 min
Apr 29, 6:50 PM CDTSevere Thunderstorm WatchSPCAustin, Bastrop, Bell, Brazos, Burleson, Caldwell and 20 more4 hr

Nearby

Tornado Watches in Texas, 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.