Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 1844
The Storm Prediction Center issued this mesoscale discussion at Oct 12, 2021, 9:18 PM CDT for 18 counties in Oklahoma; 5 counties in Texas. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- Oct 12, 2021, 9:18 PM CDT (02:18 UTC)
- Expired
- Oct 12, 2021, 11:15 PM CDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 523
All 23 counties
Beaver County, OK, Beckham County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Comanche County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Grady County, OK, Greer County, OK, Harper County, OK, Kingfisher County, OK, Kiowa County, OK, Major County, OK, Roger Mills County, OK, Washita County, OK, Woodward County, OK, Hemphill County, TX, Lipscomb County, TX, Ochiltree County, TX, Roberts County, TX, Wheeler County, TX
The radar
The Altus AFB radar (KFDR), 146 km from the middle of the area, began a volume at 02:19 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
Norman, OK (KOUN), launched 00:00Z, 2.3 hours before the alert went out and 166 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
- 496 J/kg
- Mixed-layer CIN
- -164 J/kg
- Mixed-layer LCL
- 662 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 331 m²/s²
- 0-3 km storm-relative helicity
- 372 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.5
The text
As transmitted.
810
ACUS11 KWNS 130219
SWOMCD
SPC MCD 130218
OKZ000-KSZ000-TXZ000-130415-
Mesoscale Discussion 1844
NWS Storm Prediction Center Norman OK
0918 PM CDT Tue Oct 12 2021
Areas affected...Western Oklahoma and the eastern Oklahoma and Texas
Panhandles
Concerning...Tornado Watch 523...
Valid 130218Z - 130415Z
The severe weather threat for Tornado Watch 523 continues.
SUMMARY...The threat for tornadoes and severe wind continues across
WW 523. The greatest near-term threats will reside with a pair of
supercells across western OK, as well as intensifying storms across
the OK/TX Panhandles.
DISCUSSION...Vertical wind profilers from across the southern Plains
have shown strengthening flow in the lowest 2-3 km over the past
hour as the surface low across the southern/central High Plains
continues to deepen and the main synoptic wave ejects into the
Plains. This has boosted effective SRH to around 400 m2/s2 across
much of WW 523, and aided in the organization and longevity of a
pair of tornadic supercells across western OK. These two cells will
continue to pose a tornado threat for the next 1-2 hours, but the
longevity of the threat is uncertain due to a less favorable
thermodynamic environment with eastern extent. Additional discrete
cells ahead of the approaching cold front remain possible, but
appears unlikely given recent failed attempts at initiation near
Woodward, OK.
To the west, convection along the Pacific cold front is intensifying
as the front encounters a more unstable air mass. Severe winds have
already been reported with this line across the Panhandles, and will
continue to be possible as convection continues to intensify over
the coming hours. Given the strongly sheared environment ahead of
this line, QLCS tornadoes will also be possible - especially in the
vicinity of any northwest to southeast surges where line-normal 0-3
km bulk shear values will be maximized to near 40-45 knots.
..Moore.. 10/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...DDC...AMA...
LAT...LON 34889988 35380065 35990127 36740115 37040086 36989947
36579857 36369791 35989767 35569766 35179770 34699778
34409809 34409867 34889988SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 12, 7:30 PM CDT | Mesoscale Discussion | SPC | Beaver, Beckham, Caddo, Comanche, Cotton, Custer and 10 more | 2 hr |
| Oct 12, 11:05 PM CDT | Tornado Watch | SPC | Alfalfa, Beaver, Beckham, Blaine, Caddo, Canadian and 19 more | 7 hr |
| Oct 13, 1:18 AM CDT | Mesoscale Discussion | SPC | Alfalfa, Beckham, Blaine, Custer, Dewey, Ellis and 7 more | 87 min |
| Oct 13, 3:26 AM CDT | Mesoscale Discussion | SPC | Blaine, Caddo, Canadian, Garfield, Grant, Jackson and 6 more | 94 min |
| Oct 13, 5:16 AM CDT | Mesoscale Discussion | SPC | Cleveland, Creek, Grady, Lincoln, Logan, McClain and 9 more | 59 min |
| Oct 13, 7:34 AM CDT | Mesoscale Discussion | SPC | Cherokee, Craig, Delaware, Hughes, McIntosh, Mayes and 9 more | 116 min |
| Oct 13, 3:59 PM CDT | Mesoscale Discussion | SPC | Brown, Coleman, Collin, Comanche, Cooke, Denton and 9 more | 91 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.