Alert archive / Texas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 586

August 20, 201211 counties in New Mexico; Cimarron County, Oklahoma; 28 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Aug 20, 2012, 2:59 PM MDT for 11 counties in New Mexico; Cimarron County, Oklahoma; 28 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 20, 2012, 2:59 PM MDT (20:59 UTC)
Expired
Aug 20, 2012, 10:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 40 counties

Chaves County, NM, Curry County, NM, De Baca County, NM, Eddy County, NM, Guadalupe County, NM, Harding County, NM, Lea County, NM, Quay County, NM, Roosevelt County, NM, San Miguel County, NM, Union County, NM, Cimarron County, OK, Armstrong County, TX, Bailey County, TX, Briscoe County, TX, Carson County, TX, Castro County, TX, Cochran County, TX, Collingsworth County, TX, Dallam County, TX, Deaf Smith County, TX, Donley County, TX, Floyd County, TX, Gaines County, TX, Gray County, TX, Hale County, TX, Hartley County, TX, Hockley County, TX, Lamb County, TX, Lubbock County, TX, Moore County, TX, Oldham County, TX, Parmer County, TX, Potter County, TX, Randall County, TX, Sherman County, TX, Swisher County, TX, Terry County, TX, Wheeler County, TX, Yoakum County, TX

The radar

The Cannon AFB radar (KFDX), 68 km from the middle of the area, began a volume at 21:01 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 20, 4:20 PM MDTSevere Thunderstorm WarningAMACimarron38 min
Aug 20, 4:23 PM MDTSevere Thunderstorm WarningAMADeaf Smith, Randall49 min
Aug 20, 4:26 PM MDTSevere Thunderstorm WarningLUBCastro49 min
Aug 20, 4:48 PM MDTSevere Thunderstorm WarningABQCurry42 min
Aug 20, 4:50 PM MDTSevere Thunderstorm WarningLUBCastro, Lamb25 min
Aug 20, 5:01 PM MDTSevere Thunderstorm WarningAMAPotter59 min
Aug 20, 5:03 PM MDTSevere Thunderstorm WarningLUBBailey, Castro, Lamb, Parmer57 min
Aug 20, 5:21 PM MDTFlash Flood WarningABQChaves, De Baca114 min
Aug 20, 5:31 PM MDTSevere Thunderstorm WarningAMADallam, Hartley, Moore, Oldham, Sherman59 min
Aug 20, 5:34 PM MDTSevere Thunderstorm WarningAMADeaf Smith, Oldham56 min
Aug 20, 5:58 PM MDTSevere Thunderstorm WarningLUBCastro, Lamb62 min
Aug 20, 5:59 PM MDTSevere Thunderstorm WarningAMAHartley, Hutchinson, Moore, Oldham, Potter61 min
Aug 20, 6:25 PM MDTSevere Thunderstorm WarningAMADeaf Smith, Randall50 min
Aug 20, 6:27 PM MDTSevere Thunderstorm WarningABQCurry, De Baca, Quay, Roosevelt23 min
Aug 20, 6:32 PM MDTSevere Thunderstorm WarningAMACarson, Hutchinson, Moore, Potter58 min
Aug 20, 6:32 PM MDTSevere Thunderstorm WarningLUBCastro, Swisher28 min
Aug 20, 6:48 PM MDTFlash Flood WarningAMARandall118 min
Aug 20, 6:49 PM MDTSevere Thunderstorm WarningAMAArmstrong, Randall56 min
Aug 20, 6:55 PM MDTFlash Flood WarningAMAPotter113 min
Aug 20, 7:31 PM MDTSevere Thunderstorm WarningAMAArmstrong, Carson, Donley, Gray43 min
Aug 20, 8:11 PM MDTSevere Thunderstorm WarningLUBBriscoe, Floyd, Hall, Motley49 min
Aug 20, 8:40 PM MDTSevere Thunderstorm WarningLUBLubbock35 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

Amarillo Airport, TX (KAMA), launched 12:00Z, 9.0 hours before the alert went out and 171 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, Amarillo Airport, TX at 12:00Z on 2012-08-20Temperature 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, Amarillo Airport, TX at 12:00Z on 2012-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 169 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2358 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
419 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 2:40 PM MDTMesoscale DiscussionSPCChaves, Curry, De Baca, Eddy, Guadalupe, Harding and 5 more35 min
Aug 20, 5:04 PM MDTMesoscale DiscussionSPCCurry, De Baca, Lea, Quay, Roosevelt116 min

Nearby

Severe Thunderstorm Watches in Texas, 2012Severe Thunderstorm Watches in New Mexico, 2012Severe Thunderstorm Watches in Oklahoma, 2012Every severe thunderstorm watch in 2012

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.