Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 1253
The Storm Prediction Center issued this mesoscale discussion at Jul 10, 2021, 11:56 PM CDT for 18 counties in Oklahoma; 7 counties in Texas. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Jul 10, 2021, 11:56 PM CDT (04:56 UTC)
- Expired
- Jul 11, 2021, 1:30 AM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 368...370
All 25 counties
Atoka County, OK, Bryan County, OK, Carter County, OK, Choctaw County, OK, Coal County, OK, Comanche County, OK, Cotton County, OK, Garvin County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Kiowa County, OK, Love County, OK, Marshall County, OK, Murray County, OK, Pontotoc County, OK, Stephens County, OK, Tillman County, OK, Clay County, TX, Cooke County, TX, Grayson County, TX, Hardeman County, TX, Montague County, TX, Wichita County, TX, Wilbarger County, TX
The radar
The Altus AFB radar (KFDR), 86 km from the middle of the area, began a volume at 04:57 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
Norman, OK (KOUN), launched 00:00Z, 4.9 hours before the alert went out and 133 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
- 2495 J/kg
- Mixed-layer CIN
- -69 J/kg
- Mixed-layer LCL
- 1225 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 156 m²/s²
- 0-3 km storm-relative helicity
- 185 m²/s²
- Significant tornado parameter
- 1.4
- Supercell composite
- 14.8
The text
As transmitted.
422
ACUS11 KWNS 110456
SWOMCD
SPC MCD 110456
OKZ000-TXZ000-110630-
Mesoscale Discussion 1253
NWS Storm Prediction Center Norman OK
1156 PM CDT Sat Jul 10 2021
Areas affected...Southern OK...Far Northwest/North-Central TX
Concerning...Severe Thunderstorm Watch 368...370...
Valid 110456Z - 110630Z
The severe weather threat for Severe Thunderstorm Watch 368, 370
continues.
SUMMARY...Strong, damaging wind gusts will likely continue for the
next few hours.
DISCUSSION...Western portion of the ongoing convective line has
recently surged more southwestward towards a pocket of greater
instability. This surge coincided with storm development briefly
preceding the outflow before it was then overrun by the outflow.
This merger appears to have allowed the updrafts to become more
colocated with the outflow, strengthening the overall structure of
the line and making damaging wind gusts more likely. A 53 kt wind
gusts was reported about an hour ago in Chickasha. The more
southwestward storm motion will likely keep this line in Severe
Thunderstorm Watch 368 past its original expiration time of 0500Z.
Portion of this line moving through Pontotoc and into John and Coal
Counties has shown a bit more southeastward motion. KTLX velocity
data also shows an area stronger outflow, which looks to be related
to interaction with another outflow boundary from antecedent storms
to the east.
Airmass downstream of this line is moist and unstable, suggesting
the line should continue for at least the next several hours,
despite low-level nocturnal stabilization. The more southeastward
motion of the central portion of the line may result in the need to
expand Severe Thunderstorm Watch 370 eastward along the Red River in
TX.
..Mosier.. 07/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TSA...FWD...OUN...
LAT...LON 34689975 35009919 34759591 34099534 33659592 33579679
33609779 33699893 33909959 34199984 34689975SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 10, 7:21 PM CDT | Mesoscale Discussion | SPC | Beckham, Blaine, Caddo, Canadian, Creek, Custer and 11 more | 84 min |
| Jul 10, 8:01 PM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Creek, Haskell, Hughes, Latimer and 8 more | 89 min |
| Jul 10, 9:21 PM CDT | Mesoscale Discussion | SPC | Atoka, Carter, Cleveland, Coal, Comanche, Cotton and 18 more | 84 min |
| Jul 10, 9:35 PM CDT | Severe Thunderstorm Watch | SPC | Atoka, Bryan, Carter, Coal, Comanche, Cotton and 15 more | 5 hr |
| Jul 11, 2:46 AM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Collin, Denton, Foard and 6 more | 29 min |
| Jul 11, 11:48 AM CDT | Mesoscale Discussion | SPC | Culberson, Loving, Reeves, Ward, Winkler, Yoakum | 87 min |
| Jul 11, 12:16 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Borden, Cochran, Dawson, Ector, Gaines and 14 more | 7 hr |
| Jul 11, 2:33 PM CDT | Mesoscale Discussion | SPC | Andrews, Cochran, Dawson, Ector, Gaines, Hockley and 5 more | 87 min |
| Jul 11, 3:23 PM CDT | Severe Thunderstorm Watch | SPC | El Paso, Hudspeth | 8 hr |
| Jul 11, 6:51 PM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Cherokee, Coke, Concho, Coryell and 22 more | 84 min |
Nearby
Mesoscale Discussions in Oklahoma, 2021Mesoscale 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.