Alert archive / Oklahoma / Mesoscale Discussions in 2026

Mesoscale Discussion 921

May 31, 20267 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 31, 2026, 3:50 PM CDT for 7 counties in Oklahoma. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 31, 2026, 3:50 PM CDT (20:50 UTC)
Expired
May 31, 2026, 6:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Blaine County, OK, Canadian County, OK, Custer County, OK, Garfield County, OK, Kingfisher County, OK, Logan County, OK, Noble County, OK

The radar

The Vance AFB radar (KVNX), 81 km from the middle of the area, began a volume at 20:53 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, 8.8 hours before the alert went out and 111 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-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2026-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2196 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 12:00Z on 2026-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 220 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2196 J/kg
Mixed-layer CIN
-195 J/kg
Mixed-layer LCL
963 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
220 m²/s²
0-3 km storm-relative helicity
294 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted.

036 
ACUS11 KWNS 312050
SWOMCD
SPC MCD 312050 
OKZ000-312315-

Mesoscale Discussion 0921
NWS Storm Prediction Center Norman OK
0350 PM CDT Sun May 31 2026

Areas affected...Parts of northwest and north-central Oklahoma

Concerning...Severe potential...Watch unlikely 

Valid 312050Z - 312315Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong-severe downbursts are possible with any
storms that develop over the next several hours.

DISCUSSION...Visible satellite imagery shows deepening high-based
cumulus evolving within a zone of low-level confluence in
north-central and northwest OK -- where a sharp gradient in
low-level moisture and boundary-layer mixing is evident. Continued
heating in this zone should eventually support the development of
isolated thunderstorms this afternoon. Temperatures in the upper 90s
amid middle/upper 60s dewpoints are yielding a favorable environment
for strong to severe downbursts. Around 30 kt of effective shear in
the northern part of the area will conditionally favor storm
organization and a locally greater severe risk, though most storms
are expected to remain short-lived.

..Weinman/Thompson.. 05/31/2026

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

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

LAT...LON   35589905 35729894 36059858 36489805 36829776 36879751
            36749713 36429708 35939724 35299817 35269854 35379897
            35589905 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

Nearby

Mesoscale Discussions in Oklahoma, 2026Every mesoscale discussion in 2026

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.