Alert archive / Oklahoma / Mesoscale Discussions in 2018

Mesoscale Discussion 321

May 2, 201822 counties in Oklahoma; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 2, 2018, 6:10 PM CDT for 22 counties in Oklahoma; 6 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: May 2, 2018, 6:10 PM CDT (23:10 UTC)
Expired: May 2, 2018, 7:45 PM CDT
In force: 95 min
Issued by: the Storm Prediction Center

All 28 counties

Alfalfa County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Garfield County, OK, Grady County, OK, Grant County, OK, Jackson County, OK, Kingfisher County, OK, Kiowa County, OK, Logan County, OK, Major County, OK, McClain County, OK, Noble County, OK, Oklahoma County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Archer County, TX, Baylor County, TX, Foard County, TX, Knox County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Norman radar (KTLX), 101 km from the middle of the area, began a volume at 23:12 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, 11.2 hours before the alert went out and 94 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: 517 J/kg
Mixed-layer CIN: -198 J/kg
Mixed-layer LCL: 695 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 115 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

580 
ACUS11 KWNS 022311
SWOMCD
SPC MCD 022310 
OKZ000-KSZ000-TXZ000-030045-

Mesoscale Discussion 0321
NWS Storm Prediction Center Norman OK
0610 PM CDT Wed May 02 2018

Areas affected...Western/Central OK...Northwest TX

Concerning...Tornado Watch 62...

Valid 022310Z - 030045Z

The severe weather threat for Tornado Watch 62 continues.

SUMMARY...Threat for all severe hazards, including very large hail
and tornadoes, persists across western/central OK and adjacent
northwest TX.

DISCUSSION...Numerous discrete supercells developed during the past
several hours across portions of western OK and adjacent northwest
TX. Spatial extent between these supercells has become increasingly
small over the past hour and current trends suggest upscale growth
into an organized MCS is probable. Cells along the far southern
flank (over northwest TX) have already undergone a transition to a
more linear mode, with that general trend anticipated farther north
into west-central OK. Once that occurs, primary severe threat will
transition to damaging wind gusts, although tornadoes embedded
within the line are still possible. Until then, ongoing discrete
supercells are expected to persist within an airmass characterized
by strong instability and veered low-level wind profiles. Recent
KTLX VAD sampled 0-1 km SRH over 200 m2/s2. These supercells are
capable of all severe hazards, include very large hail and
tornadoes.

..Mosier.. 05/02/2018

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

ATTN...WFO...ICT...OUN...LUB...

LAT...LON   36159881 36889852 37019829 36879755 36229712 35279707
            34469758 33539866 33530017 34719944 36159881

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 2, 11:36 AM CDT	Mesoscale Discussion	SPC	Alfalfa, Beaver, Beckham, Custer, Dewey, Ellis and 9 more	2 hr
May 2, 12:59 PM CDT	Tornado Watch	SPC	Alfalfa, Beaver, Beckham, Blaine, Caddo, Canadian and 32 more	9 hr
May 2, 3:24 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Beckham, Blaine, Caddo, Canadian, Comanche and 21 more	3 hr
May 2, 3:13 PM CDT	Mesoscale Discussion	SPC	Coke, Concho, Crockett, Edwards, Glasscock, Irion and 12 more	2 hr
May 2, 4:41 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Callahan, Coke, Coleman, Concho, Crockett and 36 more	9 hr

Nearby

Mesoscale Discussions in Oklahoma, 2018 Mesoscale Discussions in Texas, 2018 Every 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.