Alert archive / Oklahoma / Mesoscale Discussions in 2018
Mesoscale Discussion 1313
The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2018, 5:13 PM CDT for 26 counties in Oklahoma; 16 counties in Texas. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2018, 5:13 PM CDT (22:13 UTC)
- Expired
- Aug 17, 2018, 6:45 PM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
All 42 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, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Kiowa County, OK, Latimer County, OK, Love County, OK, Marshall County, OK, McClain County, OK, McCurtain County, OK, Murray County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Cooke County, TX, Fannin County, TX, Grayson County, TX, Hardeman County, TX, Jack County, TX, Lamar County, TX, Montague County, TX, Red River County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX, Wise County, TX, Young County, TX
The radar
The Norman radar (KTLX), 145 km from the middle of the area, began a volume at 22:15 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 12:00Z, 10.2 hours before the alert went out and 132 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
- 1024 J/kg
- Mixed-layer CIN
- -99 J/kg
- Mixed-layer LCL
- 1783 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 146 m²/s²
- 0-3 km storm-relative helicity
- 198 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 3.8
The text
As transmitted.
194
ACUS11 KWNS 172214
SWOMCD
SPC MCD 172213
TXZ000-OKZ000-172345-
Mesoscale Discussion 1313
NWS Storm Prediction Center Norman OK
0513 PM CDT Fri Aug 17 2018
Areas affected...Southern OK...North TX
Concerning...Severe potential...Watch unlikely
Valid 172213Z - 172345Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated to widely scattered thunderstorms are expected
into early evening. The strongest storms may be capable of
marginally severe hail and localized strong wind gusts.
DISCUSSION...Thunderstorms have recently developed across portions
of southwest OK/northwest TX, and also southeast OK, with other
attempts at development noted along multiple surface boundaries
across southern OK into north TX. Moderate-to-strong buoyancy
(2000-3000 J/kg) will support strong initial updrafts, with modest
northwesterly midlevel flow potentially supporting transient
multicell structures capable of marginally severe hail. A few strong
wind gusts will also be possible, especially with any storms that
propagate south of the initiating boundary, where a hot and
well-mixed boundary layer is in place. Storm coverage is expected to
remain isolated to widely scattered, given the lack of larger-scale
ascent across the region, and the overall threat will remain too low
for watch issuance.
..Dean/Thompson.. 08/17/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SHV...TSA...FWD...OUN...SJT...LUB...
LAT...LON 35019995 35029804 35069527 34489460 33929450 33589450
33619525 33449627 33209750 33099846 33039936 33649963
34330001 35019995SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 9:23 AM CDT | Mesoscale Discussion | SPC | Haskell, LeFlore, Sequoyah | 97 min |
| Aug 17, 3:08 PM CDT | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 15 more | 2 hr |
Nearby
Mesoscale Discussions in Oklahoma, 2018Mesoscale Discussions in Texas, 2018Every mesoscale discussion in 2018
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.