Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 653
The Storm Prediction Center issued this mesoscale discussion at May 17, 2021, 4:53 PM CDT for 17 counties in Texas. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- May 17, 2021, 4:53 PM CDT (21:53 UTC)
- Expired
- May 17, 2021, 6:30 PM CDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 183
Counties Baylor County, TX, Callahan County, TX, Childress County, TX, Cottle County, TX, Fisher County, TX, Foard County, TX, Hardeman County, TX, Haskell County, TX, Jones County, TX, King County, TX, Knox County, TX, Nolan County, TX, Shackelford County, TX, Stonewall County, TX, Taylor County, TX, Throckmorton County, TX, Wilbarger County, TX
The radar
The Dyess AFB radar (KDYX), 104 km from the middle of the area, began a volume at 21:56 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
Midland Regional, TX (KMAF), launched 12:00Z, 9.9 hours before the alert went out and 251 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
- 1892 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 750 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 204 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 6.7
The text
As transmitted.
770
ACUS11 KWNS 172154
SWOMCD
SPC MCD 172153
TXZ000-OKZ000-172330-
Mesoscale Discussion 0653
NWS Storm Prediction Center Norman OK
0453 PM CDT Mon May 17 2021
Areas affected...Northwest TX
Concerning...Tornado Watch 183...
Valid 172153Z - 172330Z
The severe weather threat for Tornado Watch 183 continues.
SUMMARY...Thunderstorms capable of producing very large hail,
locally severe wind gusts, and a couple of tornadoes will be
possible into the evening.
DISCUSSION...At 2145Z, strong thunderstorms have developed along an
outflow boundary across portions of northwest TX. Relatively strong
heating on both sides of the boundary has largely removed MLCINH, so
continued intensification and development is expected into the early
evening. Moderate-to-strong instability (MLCAPE of 1500-2500 J/kg),
effective shear of 35-45 kt, and steep midlevel lapse rates will
support very large hail (potentially baseball-size or larger) with
the strongest cells. While low-level flow is currently weak, some
tornado risk may evolve with any supercell interacting with the
boundary, especially as the low-level jet begins to increase toward
evening. With generally steep low-level lapse rates across the area,
isolated severe wind gusts will also be possible. Some upscale
growth is possible this evening in conjunction with the intensifying
low-level jet, which would increase the threat of damaging wind with
time.
..Dean.. 05/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF...
LAT...LON 32089963 32080031 32080032 32080033 32080051 32080054
32090067 32250066 32620066 32740066 32960066 34310052
34750042 34750038 34750012 34750000 34469936 34419926
34409926 34219895 34209895 32969895 32509910 32089963
32089963SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 7:08 PM CDT | Severe Thunderstorm Watch | SPC | Cottle, Crosby, Dickens, Floyd, Garza, Hale and 8 more | 6 hr |
| May 16, 8:54 PM CDT | Mesoscale Discussion | SPC | Briscoe, Cottle, Foard, Hall, King, Knox and 1 more | 96 min |
| May 16, 9:38 PM CDT | Severe Thunderstorm Watch | SPC | Archer, Baylor, Clay, Foard, Hardeman, Haskell and 10 more | 4 hr |
| May 16, 10:46 PM CDT | Mesoscale Discussion | SPC | Baylor, Cottle, Dickens, Foard, Haskell, King and 3 more | 59 min |
| May 17, 1:09 AM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Crosby, Dickens, Fisher and 17 more | 96 min |
| May 17, 9:18 AM CDT | Mesoscale Discussion | SPC | Jasper, Jefferson, Newton, Orange | 117 min |
| May 17, 12:47 PM CDT | Mesoscale Discussion | SPC | Austin, Bastrop, Bell, Blanco, Brazoria, Brazos and 29 more | 88 min |
| May 17, 1:39 PM CDT | Mesoscale Discussion | SPC | Dallam, Hartley, Oldham | 2 hr |
| May 17, 2:11 PM CDT | Mesoscale Discussion | SPC | Andrews, Bailey, Borden, Castro, Cochran, Crane and 20 more | 2 hr |
| May 17, 2:39 PM CDT | Severe Thunderstorm Watch | SPC | Armstrong, Carson, Collingsworth, Dallam, Donley, Gray and 10 more | 8 hr |
| May 17, 3:04 PM CDT | Tornado Watch | SPC | Andrews, Bailey, Borden, Briscoe, Castro, Cochran and 39 more | 8 hr |
| May 17, 4:44 PM CDT | Tornado Watch | SPC | Baylor, Childress, Cottle, Fisher, Foard, Hardeman and 10 more | 6 hr |
| May 17, 5:10 PM CDT | Mesoscale Discussion | SPC | Dallam, Hansford, Hartley, Hutchinson, Moore, Ochiltree and 3 more | 2 hr |
| May 17, 5:36 PM CDT | Mesoscale Discussion | SPC | Andrews, Armstrong, Bailey, Borden, Briscoe, Castro and 38 more | 84 min |
| May 17, 6:13 PM CDT | Mesoscale Discussion | SPC | Dimmit, La Salle, Webb | 92 min |
| May 17, 6:40 PM CDT | Severe Thunderstorm Watch | SPC | Dimmit, Frio, La Salle, Maverick, Webb, Zavala | 4 hr |
Nearby
Mesoscale Discussions in Texas, 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.