Mesoscale Discussion 1908

Issued

Aug 10, 2026, 5:15 PM MDT (23:15 UTC)

Expired

Aug 10, 2026, 7:15 PM MDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

40%

Counties Carter County, MT, Adams County, ND, Bowman County, ND, Sioux County, ND, Slope County, ND, Campbell County, SD, Corson County, SD, Dewey County, SD, Harding County, SD, Perkins County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The Rapid City radar (KUDX), 151 km from the middle of the area, began a volume at 23:19 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.

• Severe Thunderstorm Watch 562Aug 10, 6:45 PM MDT

072 
ACUS11 KWNS 102315
SWOMCD
SPC MCD 102315 
SDZ000-NDZ000-MTZ000-110115-

Mesoscale Discussion 1908
NWS Storm Prediction Center Norman OK
0615 PM CDT Mon Aug 10 2026

Areas affected...Far southeast Montana into far southern North
Dakota and northern South Dakota

Concerning...Severe potential...Watch possible 

Valid 102315Z - 110115Z

Probability of Watch Issuance...40 percent

SUMMARY...Satellite trends are being monitored for thunderstorm
development across southeast Montana. If thunderstorms can develop
they will likely move into an air mass very favorable for severe
convection. Watch issuance is possible if this can occur.

DISCUSSION...Latest GOES imagery depicts a growing cumulus field
across southeast Montana in proximity to a weak surface
low/confluence zone. Although broad-scale forcing for ascent across
this region is weaker compared to areas further south, the nearby
thermodynamic environment appears supportive of thunderstorms with
limited capping and around 2500 J/kg MLCAPE. It remains uncertain
whether or not ascent across this region will be sufficient to
initiate and maintain deep convection, and recent guidance shows
considerable uncertainty on whether or not storms will develop
(though a few RRFS solutions do hint at this potential). 

However, if convection can develop and be sustained, it will likely
migrate east/southeast into an increasingly moist air mass where
MLCAPE values increase to around 3000-4000 J/kg. Additionally, the
KBIS VWP continues to sample 50-55 knot 0-6 km BWD, which will favor
organized convection. Storm mode would likely transition from
semi-discrete cells into an organized cluster/MCS given the
relatively dry low-level air mass and weak near-surface flow within
the zone of initiation, both of which would favor deep/expanding
cold pools. 

If initiation and clustering occurs, a threat for large hail and
severe winds will likely emerge across far southern ND and into
northwest/north-central SD. Convective trends will continue to be
monitored, and watch issuance will be considered if robust/sustained
convection becomes more imminent.

..Moore/Mosier.. 08/10/2026

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

ATTN...WFO...ABR...BIS...UNR...BYZ...

LAT...LON   44400125 45150445 45380464 45880468 46190453 46460414
            46510385 45979976 45649953 45259953 44859970 44530021
            44390065 44400125 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

Mesoscale Discussions in South Dakota, 2026Mesoscale Discussions in North Dakota, 2026Mesoscale Discussions in Montana, 2026Every mesoscale discussion in 2026

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.