Alert archive / Oklahoma / Mesoscale Discussions in 2020

Mesoscale Discussion 596

May 15, 2020Sebastian County, Arkansas; 10 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 15, 2020, 11:04 AM CDT for Sebastian County, Arkansas; 10 counties in Oklahoma. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: May 15, 2020, 11:04 AM CDT (16:04 UTC)
Expired: May 15, 2020, 12:30 PM CDT
In force: 86 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Sebastian County, AR, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, McIntosh County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Seminole County, OK, Sequoyah County, OK

The radar

The Tulsa radar (KINX), 100 km from the middle of the area, began a volume at 16:07 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.

Severe Thunderstorm Watch 186May 15, 1:35 PM CDT

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 4.1 hours before the alert went out and 171 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: 1862 J/kg
Mixed-layer CIN: -241 J/kg
Mixed-layer LCL: 909 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 292 m²/s²
0-3 km storm-relative helicity: 249 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

468 
ACUS11 KWNS 151605
SWOMCD
SPC MCD 151604 
ARZ000-OKZ000-151730-

Mesoscale Discussion 0596
NWS Storm Prediction Center Norman OK
1104 AM CDT Fri May 15 2020

Areas affected...Portions of eastern OK and far west-central AR

Concerning...Severe potential...Watch possible 

Valid 151604Z - 151730Z

Probability of Watch Issuance...40 percent

SUMMARY...An isolated threat for mainly severe wind gusts may
continue into the early afternoon. Although watch issuance is not
immediately likely, trends will continue to be monitored.

DISCUSSION...A persistent band of convection over east-central OK is
being supported by a 30-35 kt west-southwesterly low-level jet per
recent KTLX VWP. Outflow from other storms to the north is about to
reinforce this ongoing complex, with some potential for convection
to develop generally southward along an instability gradient into
the early afternoon. It remains unclear whether these storms will
pose any more than an isolated severe/damaging wind and occasional
hail threat, as the low-level jet is forecast to gradually weaken
through the afternoon. Still, the airmass downstream of this
developing cluster will continue to destabilize, and trends will be
monitored for increasing storm intensity/organization over the next
1-2 hours. At this point, watch issuance does not appear immediately
likely, but the severe threat across this region is expected to
increase later this afternoon.

..Gleason/Dial.. 05/15/2020

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

ATTN...WFO...LZK...SHV...TSA...OUN...

LAT...LON   35739668 35989612 35759578 35549532 35719471 35469432
            34889409 34529453 34379518 34509606 35179672 35739668

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 15, 1:39 PM CDT	Severe Thunderstorm Watch	SPC	Sebastian	8 hr
May 15, 3:36 PM CDT	Mesoscale Discussion	SPC	Garland, Howard, Montgomery, Pike, Polk, Scott and 2 more	84 min
May 14, 10:04 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Dewey, Ellis, Major, Woods, Woodward	116 min
May 15, 1:08 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Caddo, Carter, Choctaw, Coal and 22 more	2 hr
May 15, 6:59 PM CDT	Mesoscale Discussion	SPC	Bryan, Carter, Comanche, Cotton, Jefferson, Johnston and 5 more	2 hr

Nearby

Mesoscale Discussions in Oklahoma, 2020 Mesoscale Discussions in Arkansas, 2020 Every mesoscale discussion in 2020

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.