Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 188
The Storm Prediction Center issued this mesoscale discussion at Mar 16, 2021, 9:27 PM CDT for 36 counties in Texas. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Mar 16, 2021, 9:27 PM CDT (02:27 UTC)
- Expired
- Mar 16, 2021, 11:00 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 95%
All 36 counties
Archer County, TX, Baylor County, TX, Brown County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Eastland County, TX, Erath County, TX, Fisher County, TX, Foard County, TX, Haskell County, TX, Irion County, TX, Jack County, TX, Jones County, TX, Kimble County, TX, King County, TX, Knox County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Nolan County, TX, Palo Pinto County, TX, Runnels County, TX, San Saba County, TX, Schleicher County, TX, Shackelford County, TX, Stephens County, TX, Stonewall County, TX, Sutton County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Young County, TX
The radar
The San Angelo radar (KSJT), 84 km from the middle of the area, began a volume at 02:33 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 00:00Z, 2.5 hours before the alert went out and 218 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
- 30 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 3894 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
489
ACUS11 KWNS 170227
SWOMCD
SPC MCD 170227
TXZ000-170400-
Mesoscale Discussion 0188
NWS Storm Prediction Center Norman OK
0927 PM CDT Tue Mar 16 2021
Areas affected...northwest Texas through the Hill country
Concerning...Severe potential...Watch likely
Valid 170227Z - 170400Z
Probability of Watch Issuance...95 percent
SUMMARY...Severe storms are expected to develop from northwest Texas
into the Hill country near or shortly after 03Z and spread east
overnight. Damaging wind and large hail are the primary threats, but
a couple of tornadoes are also possible.
DISCUSSION...As of mid evening a cold front is advancing east
through western Texas, and this boundary will soon merge with the
dryline farther east. Low level moisture with upper 50s to low 60s F
dewpoints is surging northwestward beneath steep mid-level lapse
rates, and latest objective analysis show moderate instability with
1500-2000 J/kg MLCAPE east of the dryline. However, the 00Z RAOB
data from Fort Worth and RAP point-forecast soundings indicate a
capping inversion associated with warm air aloft at the base of an
elevated mixed layer. This suggests initial storm development will
likely remain confined to within the zone of forcing where the cold
front intercepts the dryline. Moreover, WV imagery shows a corridor
of deep forcing for ascent associated with a progressive shortwave
trough spreading eastward through western TX. Current estimation is
that storms will probably initiate near or shortly after 03Z. Some
discrete modes are possible initially, but storms are expected to
evolve into a dominant linear mode. Wind profiles with 50 kt
effective bulk shear will support organized storms including bowing
line segments and embedded supercells. Damaging wind and large hail
will be the main threats, but a couple of tornadoes are also
possible given sufficiently large low-level hodographs.
..Dial/Hart.. 03/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...EWX...SJT...LUB...MAF...
LAT...LON 30350131 31690099 33770066 34199969 33789821 32429784
30679889 30140013 30350131SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 16, 7:49 PM CDT | Severe Thunderstorm Watch | SPC | Collingsworth, Donley, Gray, Hemphill, Lipscomb, Roberts and 1 more | 7 hr |
| Mar 16, 10:26 PM CDT | Severe Thunderstorm Watch | SPC | Bell, Bosque, Brown, Callahan, Coke, Coleman and 44 more | 7 hr |
| Mar 17, 1:32 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Gregg, Harrison, Marion and 7 more | 118 min |
| Mar 17, 2:20 AM CDT | Mesoscale Discussion | SPC | Brown, Callahan, Coleman, Comanche, Eastland, Erath and 6 more | 85 min |
| Mar 17, 4:04 AM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Collin and 25 more | 86 min |
| Mar 17, 4:37 AM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Collin and 30 more | 5 hr |
| Mar 17, 4:38 AM CDT | Mesoscale Discussion | SPC | Armstrong, Carson, Dallam, Deaf Smith, Gray, Hansford and 11 more | 6 hr |
| Mar 17, 6:40 AM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Delta and 16 more | 95 min |
| Mar 17, 8:43 AM CDT | Tornado Watch | SPC | Angelina, Nacogdoches, Sabine, San Augustine, Shelby | 4 hr |
| Mar 17, 11:35 AM CDT | Mesoscale Discussion | SPC | Angelina, Brazoria, Chambers, Galveston, Hardin, Harris and 10 more | 85 min |
| Mar 17, 11:53 AM CDT | Tornado Watch | SPC | Hardin, Jasper, Jefferson, Newton, Orange, Tyler | 6 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.