Alert archive / Oklahoma / Mesoscale Discussions in 2021

Mesoscale Discussion 639

May 16, 20217 counties in Oklahoma; 7 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 16, 2021, 3:46 PM CDT for 7 counties in Oklahoma; 7 counties in Texas. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: May 16, 2021, 3:46 PM CDT (20:46 UTC)
Expired: May 16, 2021, 5:15 PM CDT
In force: 89 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

Counties Carter County, OK, Cotton County, OK, Jefferson County, OK, Love County, OK, Marshall County, OK, Murray County, OK, Stephens County, OK, Archer County, TX, Clay County, TX, Cooke County, TX, Jack County, TX, Montague County, TX, Wichita County, TX, Wise County, TX

The radar

The Altus AFB radar (KFDR), 133 km from the middle of the area, began a volume at 20:48 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

Shreveport, LA (KSHV), launched 12:00Z, 8.8 hours before the alert went out and 396 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 80 J/kg
Mixed-layer CIN: -171 J/kg
Mixed-layer LCL: 899 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -28 m²/s²
0-3 km storm-relative helicity: -6 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

603 
ACUS11 KWNS 162047
SWOMCD
SPC MCD 162046 
TXZ000-OKZ000-162215-

Mesoscale Discussion 0639
NWS Storm Prediction Center Norman OK
0346 PM CDT Sun May 16 2021

Areas affected...South-Central OK/Northwest TX

Concerning...Severe potential...Watch unlikely 

Valid 162046Z - 162215Z

Probability of Watch Issuance...20 percent

SUMMARY...A relatively small spatial and temporal corridor for
supercell intensification/organization exists across south-central
OK and northwest TX.

DISCUSSION...Recent visible satellite imagery shows that the area
just downstream from the outflow associated with the MCV and
persistent convection over central OK has cleared out. Temperatures
in this region have quickly increased into the upper 70s/low 80s
amid dewpoints in the mid to upper 60s. Additionally, the surface
winds within this region have backed, with numerous sites now
reporting southeasterly winds around 10 kt. Overall convective
evolution within this corridor is uncertain, particularly given the
westward/northwestward moving outflow coming from north-central TX.
However, potential exists for the development of a strong to severe
storm, particularly if the storm over Cotton County OK is able to
maintain intensity. As a result, a very conditional risk for hail,
damaging wind gusts, and perhaps even a brief tornado exists.

..Mosier/Guyer.. 05/16/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...OUN...

LAT...LON   33819889 34339853 34659763 34649723 34629704 34389673
            33879664 33739668 33479676 33239711 33129754 33079813
            33219866 33399892 33819889

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 15, 9:09 PM CDT	Mesoscale Discussion	SPC	Texas	96 min
May 16, 2:23 PM CDT	Mesoscale Discussion	SPC	Cimarron	2 hr
May 16, 3:43 PM CDT	Severe Thunderstorm Watch	SPC	Cimarron, Texas	7 hr
May 15, 9:32 PM CDT	Mesoscale Discussion	SPC	Andrews, Borden, Crane, Crockett, Dawson, Ector and 11 more	88 min
May 16, 12:15 PM CDT	Mesoscale Discussion	SPC	Anderson, Bastrop, Bell, Brazos, Burleson, Cherokee and 22 more	2 hr
May 16, 3:16 PM CDT	Mesoscale Discussion	SPC	Armstrong, Bailey, Briscoe, Carson, Castro, Cochran and 12 more	119 min
May 16, 5:52 PM CDT	Mesoscale Discussion	SPC	Glasscock, Howard, Irion, Midland, Reagan, Sterling	53 min
May 16, 6:12 PM CDT	Mesoscale Discussion	SPC	Armstrong, Briscoe, Carson, Castro, Childress, Deaf Smith and 7 more	93 min
May 16, 6:35 PM CDT	Severe Thunderstorm Watch	SPC	Borden, Coke, Crockett, Dawson, Fisher, Glasscock and 12 more	4 hr

Nearby

Mesoscale Discussions in Oklahoma, 2021 Mesoscale Discussions in Texas, 2021 Every 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.