Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 159
The Storm Prediction Center issued this mesoscale discussion at Mar 12, 2021, 8:11 PM CST for Harmon County, Jackson County, Tillman County, Oklahoma; 24 counties in Texas. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Mar 12, 2021, 8:11 PM CST (02:11 UTC)
- Expired
- Mar 12, 2021, 9:15 PM CST
- In force
- 64 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 17
All 27 counties
Harmon County, OK, Jackson County, OK, Tillman County, OK, Baylor County, TX, Briscoe County, TX, Childress County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Floyd County, TX, Foard County, TX, Garza County, TX, Hale County, TX, Hall County, TX, Hardeman County, TX, Hockley County, TX, Kent County, TX, King County, TX, Knox County, TX, Lamb County, TX, Lubbock County, TX, Lynn County, TX, Motley County, TX, Stonewall County, TX, Terry County, TX, Wichita County, TX, Wilbarger County, TX
The radar
The Lubbock radar (KLBB), 105 km from the middle of the area, began a volume at 02:13 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.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Amarillo Airport, TX (KAMA), launched 00:00Z, 2.2 hours before the alert went out and 161 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.
- Mixed-layer CAPE
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 566 m above ground
- 0-6 km bulk shear
- 92 kt
- 0-1 km storm-relative helicity
- 384 m²/s²
- 0-3 km storm-relative helicity
- 512 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
649
ACUS11 KWNS 130212
SWOMCD
SPC MCD 130211
TXZ000-OKZ000-130315-
Mesoscale Discussion 0159
NWS Storm Prediction Center Norman OK
0811 PM CST Fri Mar 12 2021
Areas affected...Northwest TX...Southwestern OK
Concerning...Tornado Watch 17...
Valid 130211Z - 130315Z
The severe weather threat for Tornado Watch 17 continues.
SUMMARY...Severe threat will continue across parts of northwest TX
into southwestern OK. New severe thunderstorm watch is warranted to
account for this extended threat.
DISCUSSION...Sustained low-level warm advection will be the primary
instigator in generating new convection across the TX South Plains
tonight. Over the last half hour or so, new thunderstorms have
developed from northern Gaines County TX to Terry County TX. This
activity should spread/develop northeast through the late evening
hours.
Downstream, a long-lived supercell is tracking along the Cottle/King
County line. This storm will soon exit ww017 into the southwestern
portions of OUN CWA. 00z sounding from OUN was quite moist through
3km, but modestly unstable with SBCAPE on the order of 1700 J/kg.
Given the observed shear/buoyancy it appears the TX South Plains
convection will likely be maintained as it spreads downstream. New
severe thunderstorm watch will likely be issued by 0230z.
..Darrow.. 03/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...SJT...LUB...AMA...MAF...
LAT...LON 34370247 34800026 34699891 33759855 33249980 32820287
34370247SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 12, 11:08 PM CST | Mesoscale Discussion | SPC | Beckham, Harmon, Roger Mills | 2 hr |
| Mar 13, 7:36 AM CST | Mesoscale Discussion | SPC | Cimarron | 2 hr |
| Mar 13, 1:52 PM CST | Mesoscale Discussion | SPC | Harmon | 113 min |
| Mar 12, 8:38 PM CST | Severe Thunderstorm Watch | SPC | Armstrong, Baylor, Briscoe, Carson, Childress, Cochran and 29 more | 5 hr |
| Mar 13, 1:06 AM CST | Mesoscale Discussion | SPC | Childress, Cottle, Foard, Hardeman, Motley | 54 min |
| Mar 13, 11:48 AM CST | Mesoscale Discussion | SPC | Bailey, Castro, Cochran, Deaf Smith, Hale, Hockley and 7 more | 117 min |
| Mar 13, 12:36 PM CST | Tornado Watch | SPC | Bailey, Castro, Cochran, Deaf Smith, Hale, Hockley and 8 more | 5 hr |
| Mar 13, 2:26 PM CST | Tornado Watch | SPC | Armstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 19 more | 7 hr |
| Mar 13, 2:39 PM CST | Mesoscale Discussion | SPC | Andrews, Borden, Crane, Crockett, Dawson, Ector and 18 more | 2 hr |
| Mar 13, 3:23 PM CST | Tornado Watch | SPC | Borden, Coke, Crane, Crockett, Dawson, Fisher and 18 more | 6 hr |
| Mar 13, 3:46 PM CST | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Donley, Floyd, Hale and 5 more | 59 min |
| Mar 13, 4:10 PM CST | Mesoscale Discussion | SPC | Armstrong, Carson, Hutchinson, Randall | 65 min |
| Mar 13, 5:46 PM CST | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 18 more | 89 min |
Nearby
Mesoscale Discussions in Texas, 2021Mesoscale Discussions in Oklahoma, 2021Every mesoscale discussion in 2021
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.