Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 813
The Storm Prediction Center issued this mesoscale discussion at May 22, 2017, 8:50 PM CDT for 7 counties in Oklahoma; 16 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 22, 2017, 8:50 PM CDT (01:50 UTC)
- Expired
- May 22, 2017, 11:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 23 counties
Carter County, OK, Comanche County, OK, Cotton County, OK, Jefferson County, OK, Love County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Cooke County, TX, Foard County, TX, Hardeman County, TX, Jack County, TX, Knox County, TX, Montague County, TX, Palo Pinto County, TX, Stephens County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX, Wise County, TX, Young County, TX
The radar
The Altus AFB radar (KFDR), 61 km from the middle of the area, began a volume at 01:52 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, 1.8 hours before the alert went out and 171 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
- 26 J/kg
- Mixed-layer CIN
- -115 J/kg
- Mixed-layer LCL
- 1383 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 69 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -0.1
The text
As transmitted.
204
ACUS11 KWNS 230150
SWOMCD
SPC MCD 230150 COR
TXZ000-OKZ000-230415-
Mesoscale Discussion 0813
NWS Storm Prediction Center Norman OK
0850 PM CDT Mon May 22 2017
Areas affected...Northwest and North-central Texas...Southwest
Oklahoma
Concerning...Severe potential...Watch unlikely
Valid 230150Z - 230415Z
CORRECTED FOR WORDING
Probability of Watch Issuance...20 percent
SUMMARY...An isolated severe threat will likely continue for a
couple more hours across southwest Oklahoma and northwest to
north-central Texas. Isolated large hail and a few strong wind gusts
will be possible. Although weather watch issuance is not expected,
the area will continue to be monitored.
DISCUSSION...Several thunderstorms with some severe, are located
from near the Childress, Texas area east-northeastward to the
vicinity of Lawton, Oklahoma. These storms are located along an
outflow boundary in which surface dewpoints to the south of the
boundary range from the upper 50s F in northwest Texas to the lower
60s F across south-central Oklahoma and north-central Texas. This is
contributing to weak instability ahead of the boundary. In spite of
this, the Frederick WSR-88D VWP shows moderate deep-layer shear with
40 kt of westerly flow in the mid-levels. This combined with 700-500
mb lapse rates of around 7.5 C/km evident on the Amarillo 00Z
sounding, should be enough for storm rotation and isolated large
hail. The latest short-term model guidance suggests that this
convection will move east-southeastward across northwest Texas and
southern Oklahoma over the next couple of hours but weaken gradually
as instability decreases across the region later this evening.
..Broyles.. 05/23/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...SJT...LUB...
LAT...LON 34819793 34559962 34210013 33609990 32469859 32989743
34059704 34819793SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 22, 7:26 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Borden, Callahan, Cochran, Coke, Crane and 40 more | 6 hr |
| May 23, 2:34 PM CDT | Mesoscale Discussion | SPC | Bandera, Bastrop, Bell, Bexar, Blanco, Brazos and 27 more | 116 min |
| May 23, 3:33 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Angelina, Atascosa, Austin, Bastrop, Bell and 51 more | 7 hr |
| May 23, 6:54 PM CDT | Severe Thunderstorm Watch | SPC | Aransas, Bee, Calhoun, Duval, Goliad, Jim Wells and 9 more | 3 hr |
| May 23, 6:58 PM CDT | Mesoscale Discussion | SPC | Aransas, Austin, Bee, Calhoun, Colorado, DeWitt and 17 more | 2 hr |
Nearby
Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Oklahoma, 2017Every mesoscale discussion in 2017
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.