Alert archive / Texas / Mesoscale Discussions in 2020
Mesoscale Discussion 950
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2020, 1:01 AM CDT for 7 counties in Oklahoma; 12 counties in Texas. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2020, 1:01 AM CDT (06:01 UTC)
- Expired
- Jun 21, 2020, 3:00 AM CDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Carter County, OK, Cotton County, OK, Jefferson County, OK, Love County, OK, Marshall County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Collin County, TX, Cooke County, TX, Denton County, TX, Grayson County, TX, Jack County, TX, Montague County, TX, Wichita County, TX, Wilbarger County, TX, Wise County, TX
The radar
The Altus AFB radar (KFDR), 101 km from the middle of the area, began a volume at 06:03 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
Fort Worth, TX (KFWD), launched 00:00Z, 6.0 hours before the alert went out and 143 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
- 1508 J/kg
- Mixed-layer CIN
- -57 J/kg
- Mixed-layer LCL
- 1465 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 89 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 3.0
The text
As transmitted.
067
ACUS11 KWNS 210602
SWOMCD
SPC MCD 210601
OKZ000-TXZ000-210800-
Mesoscale Discussion 0950
NWS Storm Prediction Center Norman OK
0101 AM CDT Sun Jun 21 2020
Areas affected...Parts of southern Oklahoma into north central Texas
Concerning...Severe potential...Watch possible
Valid 210601Z - 210800Z
Probability of Watch Issuance...40 percent
SUMMARY...Increasing and intensifying thunderstorm development is
possible across the region through 4-7 AM CDT, which probably will
pose at least some risk for severe hail and wind. It is not certain
that a severe weather watch will be needed, but trends will continue
to be monitored for this possibility.
DISCUSSION...New attempts at thunderstorm initiation appear ongoing
along the Red River near Wichita Falls TX. This probably is being
supported by forcing for ascent associated with warm advection in
the 850-700 mb layer. This is occurring along a thermal gradient
around 700 mb that reflects stronger mid-level inhibition to the
southwest, and extends east-southeastward into north central Texas,
into areas near/north of the Dallas-Fort Worth Metroplex.
Mid/upper support for further convective development remains
unclear, but various model output suggest that it is possible that
activity could be increasingly enhanced by a subtle perturbation
approaching from the northwest. Otherwise, convection is forming in
an environment that is characterized by sizable CAPE (2000-3000
J/kg) and at least modest shear. The vertical shear is largely due
to pronounced veering of weak to modest winds with height in the
lower/mid troposphere, and may be sufficient for supercell
structures which could pose a risk for severe hail and locally
strong surface gusts.
An upscale growing, organizing cluster of storms which could
eventually produce a southeastward surging surface cold pool might
not be out of the question. But until this occurs, storms should
tend to only slow propagate to the east-southeast and severe weather
potential may remain relatively isolated and localized.
..Kerr/Grams.. 06/21/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...
LAT...LON 34629843 34559772 33999660 33139620 32939790 33539920
34539933 34629843SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 11:13 PM CDT | Mesoscale Discussion | SPC | Harper | 92 min |
| Jun 21, 1:21 AM CDT | Severe Thunderstorm Watch | SPC | Bryan, Carter, Cotton, Jefferson, Johnston, Love and 3 more | 6 hr |
| Jun 21, 6:56 AM CDT | Mesoscale Discussion | SPC | Bryan, Choctaw | 2 hr |
| Jun 21, 3:04 PM CDT | Mesoscale Discussion | SPC | Beaver, Beckham, Dewey, Ellis, Harmon, Harper and 4 more | 116 min |
| Jun 21, 5:50 PM CDT | Severe Thunderstorm Watch | SPC | Alfalfa, Beaver, Beckham, Blaine, Caddo, Canadian and 40 more | 9 hr |
Nearby
Mesoscale Discussions in Texas, 2020Mesoscale Discussions in Oklahoma, 2020Every mesoscale discussion in 2020
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.