Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 666
The Storm Prediction Center issued this mesoscale discussion at May 17, 2021, 11:37 PM CDT for 15 counties in Texas. It was in force for 83 min.
The area
The outline as issued.
The facts
- Issued
- May 17, 2021, 11:37 PM CDT (04:37 UTC)
- Expired
- May 18, 2021, 1:00 AM CDT
- In force
- 83 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 186
Counties Bosque County, TX, Brown County, TX, Comanche County, TX, Denton County, TX, Eastland County, TX, Erath County, TX, Hamilton County, TX, Hood County, TX, Jack County, TX, Johnson County, TX, Palo Pinto County, TX, Parker County, TX, Somervell County, TX, Tarrant County, TX, Wise County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 85 km from the middle of the area, began a volume at 04:39 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 nearest sounding before it
Fort Worth, TX (KFWD), launched 00:00Z, 4.6 hours before the alert went out and 96 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
- 392 J/kg
- Mixed-layer CIN
- -323 J/kg
- Mixed-layer LCL
- 1247 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- -57 m²/s²
- 0-3 km storm-relative helicity
- -5 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
025
ACUS11 KWNS 180438
SWOMCD
SPC MCD 180437
TXZ000-180600-
Mesoscale Discussion 0666
NWS Storm Prediction Center Norman OK
1137 PM CDT Mon May 17 2021
Areas affected...Portions of North TX
Concerning...Severe Thunderstorm Watch 186...
Valid 180437Z - 180600Z
The severe weather threat for Severe Thunderstorm Watch 186
continues.
SUMMARY...The threat for at least isolated damaging wind will
persist through at least 06Z, and possibly beyond.
DISCUSSION...At 0430Z, an MCS is continuing to move eastward across
north TX. The southern portion of the MCS, to the southwest of the
Metroplex, has shown signs of increasing organization, with a
well-defined 50-60 kt rear-inflow jet noted between 2-5 km on the
KDYX VWP. While this would suggest an increasing damaging wind risk,
other competing factors may mitigate the threat, such as increasing
MLCINH across the region and the primary outflow tending to surge
ahead of the leading convection.
Some damaging wind risk is expected to persist until the 06Z
expiration time of WW 186, with some potential for the threat to
last beyond that time and extend east of the current watch.
Depending on convective trends over the next hour, watch
extension/expansion may be needed prior to 06Z.
..Dean.. 05/18/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...SJT...
LAT...LON 31779942 32419889 33219831 33659787 33639738 33269707
32479687 31949726 31639790 31559859 31609927 31779942SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 7:04 PM CDT | Mesoscale Discussion | SPC | Archer, Bosque, Brown, Clay, Comanche, Eastland and 15 more | 86 min |
| May 17, 7:23 PM CDT | Mesoscale Discussion | SPC | Carson, Dallam, Gray, Hansford, Hartley, Hemphill and 8 more | 2 hr |
| May 17, 7:32 PM CDT | Tornado Watch | SPC | Brown, Callahan, Coke, Coleman, Concho, McCulloch and 4 more | 3 hr |
| May 17, 7:37 PM CDT | Mesoscale Discussion | SPC | Callahan, Coke, Coleman, Glasscock, Howard, Jones and 6 more | 83 min |
| May 17, 8:04 PM CDT | Severe Thunderstorm Watch | SPC | Archer, Clay, Comanche, Eastland, Erath, Hamilton and 11 more | 5 hr |
| May 17, 8:34 PM CDT | Mesoscale Discussion | SPC | Atascosa, Dimmit, Frio, La Salle, McMullen, Maverick and 2 more | 116 min |
| May 17, 9:28 PM CDT | Mesoscale Discussion | SPC | Carson, Collingsworth, Donley, Gray, Hansford, Hemphill and 7 more | 2 hr |
| May 17, 9:44 PM CDT | Mesoscale Discussion | SPC | Armstrong, Borden, Briscoe, Childress, Collingsworth, Cottle and 15 more | 91 min |
| May 17, 10:23 PM CDT | Mesoscale Discussion | SPC | Archer, Brown, Callahan, Clay, Coke, Coleman and 16 more | 97 min |
| May 17, 10:35 PM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Brewster, Crane, Crockett, Dawson and 13 more | 85 min |
| May 17, 10:58 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Borden, Brown, Coke, Coleman, Concho and 22 more | 7 hr |
| May 18, 1:02 AM CDT | Mesoscale Discussion | SPC | Brooks, Duval, Jim Hogg | 58 min |
| May 18, 1:29 AM CDT | Mesoscale Discussion | SPC | Coke, Concho, Crane, Crockett, Ector, Glasscock and 13 more | 91 min |
| May 18, 5:07 AM CDT | Mesoscale Discussion | SPC | Coke, Concho, Irion, Reagan, Runnels, Schleicher and 2 more | 53 min |
| May 18, 1:18 PM CDT | Mesoscale Discussion | SPC | Atascosa, Austin, Bastrop, Bexar, Brazos, Burleson and 28 more | 117 min |
| May 18, 1:57 PM CDT | Mesoscale Discussion | SPC | Bailey, Castro, Deaf Smith, Parmer, Randall, Swisher | 3 hr |
| May 18, 2:29 PM CDT | Tornado Watch | SPC | Anderson, Atascosa, Austin, Bastrop, Bexar, Blanco and 30 more | 7 hr |
| May 18, 2:30 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more | 2 hr |
| May 18, 3:51 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 11 more | 5 hr |
| May 18, 3:52 PM CDT | Mesoscale Discussion | SPC | Bastrop, Caldwell, Colorado, Fayette, Gonzales, Guadalupe and 2 more | 83 min |
| May 18, 5:10 PM CDT | Mesoscale Discussion | SPC | La Salle, McMullen, Webb | 95 min |
| May 18, 5:39 PM CDT | Mesoscale Discussion | SPC | Bowie, Cass, Gregg, Harrison, Marion, Morris and 1 more | 2 hr |
| May 18, 6:07 PM CDT | Mesoscale Discussion | SPC | Armstrong, Borden, Briscoe, Carson, Castro, Cochran and 17 more | 113 min |
| May 18, 6:13 PM CDT | Mesoscale Discussion | SPC | Austin, Brazos, Burleson, Colorado, DeWitt, Fayette and 14 more | 92 min |
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.