Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 1111
The Storm Prediction Center issued this mesoscale discussion at Jun 26, 2021, 12:59 PM CDT for 18 counties in Oklahoma; 21 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 26, 2021, 12:59 PM CDT (17:59 UTC)
- Expired
- Jun 26, 2021, 3:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 39 counties
Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Garvin County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Jefferson County, OK, Kiowa County, OK, McClain County, OK, Oklahoma County, OK, Pottawatomie County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Archer County, TX, Baylor County, TX, Childress County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Fisher County, TX, Foard County, TX, Garza County, TX, Hall County, TX, Hardeman County, TX, Haskell County, TX, Kent County, TX, King County, TX, Knox County, TX, Motley County, TX, Scurry County, TX, Stonewall County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX
The radar
The Altus AFB radar (KFDR), 51 km from the middle of the area, began a volume at 18:02 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 12:00Z, 6.0 hours before the alert went out and 232 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
- 377 J/kg
- Mixed-layer CIN
- -28 J/kg
- Mixed-layer LCL
- 524 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 73 m²/s²
- 0-3 km storm-relative helicity
- 91 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 1.2
The text
As transmitted.
115
ACUS11 KWNS 261759
SWOMCD
SPC MCD 261759
OKZ000-TXZ000-262000-
Mesoscale Discussion 1111
NWS Storm Prediction Center Norman OK
1259 PM CDT Sat Jun 26 2021
Areas affected...Northwest Texas and southwest Oklahoma
Concerning...Severe potential...Watch possible
Valid 261759Z - 262000Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorm initiation is possible in the next few hours
across northwest Texas and southwest Oklahoma. Storms may pose a
hail/wind risk, and a watch is possible in the coming hours to
address this potential.
DISCUSSION...Recent GOES imagery reveals a field of increasing
strato-cumulus across northwest TX into southwest OK. This field is
primarily oriented along a surface trough/residual outflow boundary
and some signs of vertical deepening have been noted in the past
hour. Regional water-vapor imagery suggests a mid-level impulse is
approaching the region from the west/southwest that is aiding in
lift along the boundary. This feature may be the impetus for
convective initiation early this afternoon as weak synoptic lift and
daytime heating drive increasing instability and erode lingering
inhibition. Recent hi-res guidance supports this idea, suggesting
that storms may initiate in this region by 19-20Z.
Initially discrete storms along the boundary will likely pose a
hail/wind risk thanks to sufficient instability (around 1500 J/kg
MLCAPE per mesoanalysis estimates) and deep layer shear (35-40 knots
of 0-6 km shear noted in KTLX VWP observations). Low-level shear may
be enhanced along and north of a northward retreating outflow
boundary/effective warm front where near-surface winds are backed.
This could support a window for more organized discrete convection
over southern/southwest OK before storm clustering and gradual
upscale growth occurs. The severe threat further northeast across
central OK is somewhat uncertain due to the more stable cold-pool
air mass in place (though destabilization is possible given
sufficiently limited cloud cover). Nonetheless, a watch is possible
to address the initial wind/hail concern.
..Moore/Hart.. 06/26/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF...
LAT...LON 33620175 34430075 34839994 35239921 35599832 35649755
35609722 35219687 34709692 33769832 33199915 32720003
32630091 32980151 33300171 33620175SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 25, 8:49 PM CDT | Mesoscale Discussion | SPC | Beckham, Blaine, Custer, Dewey, Greer, Harmon and 3 more | 86 min |
| Jun 25, 11:36 PM CDT | Mesoscale Discussion | SPC | Ellis, Roger Mills | 84 min |
| Jun 25, 11:42 PM CDT | Mesoscale Discussion | SPC | Craig, Nowata, Osage, Ottawa, Washington | 63 min |
| Jun 25, 11:59 PM CDT | Severe Thunderstorm Watch | SPC | Beckham, Blaine, Caddo, Canadian, Cleveland, Custer and 11 more | 5 hr |
| Jun 26, 1:53 AM CDT | Mesoscale Discussion | SPC | Blaine, Caddo, Canadian, Comanche, Custer, Grady and 7 more | 67 min |
| Jun 26, 3:27 PM CDT | Mesoscale Discussion | SPC | Harmon | 2 hr |
| Jun 26, 3:48 PM CDT | Severe Thunderstorm Watch | SPC | Caddo, Carter, Comanche, Cotton, Garvin, Grady and 10 more | 9 hr |
| Jun 26, 6:27 PM CDT | Mesoscale Discussion | SPC | Comanche, Cotton, Grady, Jackson, Jefferson, McClain and 2 more | 93 min |
| Jun 26, 4:58 PM CDT | Severe Thunderstorm Watch | SPC | Bailey, Briscoe, Castro, Deaf Smith, Hale, Hall and 6 more | 8 hr |
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.