Alert archive / Wyoming / Mesoscale Discussions in 2025

Mesoscale Discussion 1069

June 1, 20255 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2025, 7:05 PM MDT for 5 counties in Wyoming. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Jun 1, 2025, 7:05 PM MDT (01:05 UTC)
Expired
Jun 1, 2025, 8:30 PM MDT
In force
85 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Campbell County, WY, Crook County, WY, Johnson County, WY, Natrona County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 203 km from the middle of the area, began a volume at 01:07 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 nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 1.1 hours before the alert went out and 197 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, Riverton, WY at 00:00Z on 2025-06-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 00:00Z on 2025-06-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3328 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

291 
ACUS11 KWNS 020106
SWOMCD
SPC MCD 020105 
WYZ000-020230-

Mesoscale Discussion 1069
NWS Storm Prediction Center Norman OK
0805 PM CDT Sun Jun 01 2025

Areas affected...North-central/northeast Wyoming

Concerning...Severe potential...Watch unlikely 

Valid 020105Z - 020230Z

Probability of Watch Issuance...5 percent

SUMMARY...Severe winds and isolated large hail are possible with
storms this evening. A watch is not expected.

DISCUSSION...Outflow pushing westward has recently interacted with
portions of the Big Horns and promoted rather rapid convective
development despite very modest buoyancy. Additional activity has
also developed along the surface boundary. Given the steep mid-level
lapse rates sampled by the 00Z RIW sounding and 25-30 kts of shear,
a couple strong to severe storms are possible early this evening.
The primary concern would be severe wind gusts with isolated large
hail possible as well. A cell in Natrona county did show some signs
of weak low-level rotation. This is likely due to the modest surface
vorticity along the boundary. The tornado threat is quite low, but a
brief spin-up in this scenario could occur.

..Wendt/Hart.. 06/02/2025

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

ATTN...WFO...UNR...CYS...BYZ...RIW...

LAT...LON   43610794 44430729 44720594 44860483 44700453 44190469
            43840503 43190569 42770710 42950760 43610794 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 2, 1:14 PM MDTMesoscale DiscussionSPCAlbany, Converse, Goshen, Laramie, Niobrara, Platte2 hr
Jun 2, 2:12 PM MDTSevere Thunderstorm WatchSPCGoshen, Laramie, Niobrara, Platte6 hr
Jun 2, 4:55 PM MDTMesoscale DiscussionSPCGoshen, Laramie, Platte2 hr

Nearby

Mesoscale Discussions in Wyoming, 2025Every mesoscale discussion in 2025

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.