Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 817
The Storm Prediction Center issued this mesoscale discussion at May 30, 2021, 8:59 PM CDT for 5 counties in Oklahoma; 12 counties in Texas. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- May 30, 2021, 8:59 PM CDT (01:59 UTC)
- Expired
- May 30, 2021, 10:30 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 226
Counties Beaver County, OK, Dewey County, OK, Ellis County, OK, Roger Mills County, OK, Woodward County, OK, Carson County, TX, Gray County, TX, Hansford County, TX, Hemphill County, TX, Hutchinson County, TX, Lipscomb County, TX, Moore County, TX, Ochiltree County, TX, Potter County, TX, Roberts County, TX, Sherman County, TX, Wheeler County, TX
The radar
The Amarillo radar (KAMA), 122 km from the middle of the area, began a volume at 02:00 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 00:00Z, 2.0 hours before the alert went out and 121 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
- 436 J/kg
- Mixed-layer CIN
- -34 J/kg
- Mixed-layer LCL
- 1025 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 88 m²/s²
- 0-3 km storm-relative helicity
- 129 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 2.7
The text
As transmitted.
671
ACUS11 KWNS 310159
SWOMCD
SPC MCD 310159
OKZ000-TXZ000-310330-
Mesoscale Discussion 0817
NWS Storm Prediction Center Norman OK
0859 PM CDT Sun May 30 2021
Areas affected...portions of the central and eastern Texas Panhandle
into extreme western Oklahoma
Concerning...Tornado Watch 226...
Valid 310159Z - 310330Z
The severe weather threat for Tornado Watch 226 continues.
SUMMARY...The severe threat continues across Tornado Watch 226.
Large hail, damaging winds, and a tornado or two are possible, with
the severe threat potentially expanding east of the current Watch.
Conditions are currently being monitored for a potential downstream
watch issuance.
DISCUSSION...Semi-discrete supercells have gradually been morphing
into a linear complex with an MCV becoming established across far
northern Hansford County, TX. Much of the more vigorous convection
has crossed into a relatively cooler airmass across a
near-stationary, northwest-southeast oriented baroclinic zone draped
across the TX Panhandle. Nonetheless, mid 60sF dewpoints overspread
by a plume of 7 C/km lapse rates yields over 1000 J/kg MLCAPE as far
east as central OK, suggesting that the ongoing storms may persist
east of the ongoing Tornado Watch. While storms are expected to
become more linear with time (posing a damaging gust threat), recent
KAMA VWPs suggest 150+ m2/s2 0-1 km SRH may also support a brief
tornado or two as well with the stronger, longer lasting
circulations embedded within linear segments. Conditions will
continue to be monitored for a possible downstream WW issuance.
..Squitieri/Guyer.. 05/31/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...AMA...
LAT...LON 35360255 36340196 36720146 36810053 36739964 36389906
35909891 35579908 35319972 35150056 35030156 35360255SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 30, 9:17 PM CDT | Severe Thunderstorm Watch | SPC | Beaver, Beckham, Custer, Dewey, Ellis, Greer and 3 more | 5 hr |
| May 30, 9:22 PM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Cochran, Cottle, Crosby, Dawson and 20 more | 83 min |
| May 30, 11:43 PM CDT | Mesoscale Discussion | SPC | Bailey, Cochran, Cottle, Crosby, Dickens, Floyd and 12 more | 92 min |
| May 31, 2:12 AM CDT | Mesoscale Discussion | SPC | Borden, Fisher, Haskell, Howard, Jones, Kent and 5 more | 3 hr |
| May 31, 11:33 AM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Brewster, Cochran, Crane, Crockett and 26 more | 87 min |
| May 31, 12:16 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Coke, Crane, Crockett, Culberson, Ector and 21 more | 9 hr |
| May 31, 2:15 PM CDT | Mesoscale Discussion | SPC | Bosque, Brown, Callahan, Coleman, Comanche, Coryell and 10 more | 2 hr |
| May 31, 2:54 PM CDT | Severe Thunderstorm Watch | SPC | Bell, Bosque, Comanche, Coryell, Ellis, Erath and 13 more | 4 hr |
| May 31, 3:29 PM CDT | Mesoscale Discussion | SPC | Andrews, Coke, Crane, Crockett, Culberson, Ector and 21 more | 91 min |
| May 31, 5:12 PM CDT | Mesoscale Discussion | SPC | Bell, Bosque, Coryell, Ellis, Falls, Freestone and 10 more | 93 min |
| May 31, 5:49 PM CDT | Mesoscale Discussion | SPC | Brewster, Pecos, Terrell | 116 min |
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.