Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 642
The Storm Prediction Center issued this mesoscale discussion at May 16, 2021, 5:52 PM CDT for 6 counties in Texas. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- May 16, 2021, 5:52 PM CDT (22:52 UTC)
- Expired
- May 16, 2021, 6:45 PM CDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Glasscock County, TX, Howard County, TX, Irion County, TX, Midland County, TX, Reagan County, TX, Sterling County, TX
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, 10.9 hours before the alert went out and 72 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
- 109 J/kg
- Mixed-layer CIN
- -294 J/kg
- Mixed-layer LCL
- 1288 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- -48 m²/s²
- 0-3 km storm-relative helicity
- -19 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
961
ACUS11 KWNS 162252
SWOMCD
SPC MCD 162252
TXZ000-162345-
Mesoscale Discussion 0642
NWS Storm Prediction Center Norman OK
0552 PM CDT Sun May 16 2021
Areas affected...southwest Texas
Concerning...Severe potential...Watch possible
Valid 162252Z - 162345Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated storms may intensify over a portion of southwest
TX and become capable of producing mainly large hail. It remains
uncertain whether storm coverage and duration will be sufficient to
warrant a WW, but short term trends are being monitored.
DISCUSSION...Early this evening deep convective initiation is
occurring along the dryline across southwest TX just southeast of
the Midland area. The atmosphere in this region is moderately to
strongly unstable with up to 2500 J/kg MLCAPE and 7.5 C/km mid-level
lapse rates. Effective bulk shear from 30-35 kt may undergo a slight
increase this evening. Overall environment appears sufficient for a
couple of supercells. However, given what appears to be a somewhat
subsident regime aloft, there is some uncertainty regarding how long
storms will last, especially with increasing convective inhibition
associated with the onset of nocturnal cooling after 01Z.
Nevertheless, at least a storm or two storm might intensify and
become capable of producing large hail through about 02Z.
..Dial/Grams.. 05/16/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SJT...MAF...
LAT...LON 31310195 32050209 32510166 32160067 31270059 30700190
31310195SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 9:09 PM CDT | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Crosby, Floyd and 11 more | 96 min |
| May 15, 9:32 PM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Crane, Crockett, Dawson, Ector and 11 more | 88 min |
| May 16, 12:15 PM CDT | Mesoscale Discussion | SPC | Anderson, Bastrop, Bell, Brazos, Burleson, Cherokee and 22 more | 2 hr |
| May 16, 3:16 PM CDT | Mesoscale Discussion | SPC | Armstrong, Bailey, Briscoe, Carson, Castro, Cochran and 12 more | 119 min |
| May 16, 3:43 PM CDT | Severe Thunderstorm Watch | SPC | Armstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 19 more | 7 hr |
| May 16, 3:46 PM CDT | Mesoscale Discussion | SPC | Archer, Clay, Cooke, Jack, Montague, Wichita and 1 more | 89 min |
| May 16, 6:12 PM CDT | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Childress, Deaf Smith and 7 more | 93 min |
| May 16, 6:35 PM CDT | Severe Thunderstorm Watch | SPC | Borden, Coke, Crockett, Dawson, Fisher, Glasscock and 12 more | 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.