Alert archive / North Dakota / Severe Thunderstorm Watches in 2026

Severe Thunderstorm Watch 621

August 23, 202614 counties in North Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Aug 23, 2026, 3:59 PM MDT for 14 counties in North Dakota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Aug 23, 2026, 3:59 PM MDT (21:59 UTC)
Expired: Aug 23, 2026, 8:21 PM MDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 65 kt

Counties Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Grant County, ND, Hettinger County, ND, McKenzie County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sioux County, ND, Slope County, ND, Stark County, ND

The radar

The Bismarck radar (KBIS), 136 km from the middle of the area, began a volume at 22:01 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 40%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Aug 23, 5:12 PM MDT	Severe Thunderstorm Warning	BIS	Adams, Bowman, Hettinger, Slope	63 min
Aug 23, 7:02 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BIS	Dunn, McLean	58 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The text

As transmitted.

277 
WWUS20 KWNS 232155
SEL1  
SPC WW 232155
NDZ000-240300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 621
NWS Storm Prediction Center Norman OK
400 PM MDT Sun Aug 23 2026

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Southwest North Dakota

* Effective this Sunday afternoon and evening from 400 PM until
  900 PM MDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Isolated significant damaging wind gusts to 75 mph possible

SUMMARY...A few supercells with large hail up to 2 inches in
diameter and isolated severe outflow gusts of 60-75 mph will be
possible into this evening.

The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 55 miles north of
Dickinson ND to 30 miles west of Lemmon SD. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 617...WW 618...WW
619...WW 620...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
32015.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 23, 1:24 PM MDT	Mesoscale Discussion	SPC	Billings, Bowman, Golden Valley, Slope	2 hr
Aug 23, 3:49 PM MDT	Mesoscale Discussion	SPC	Adams, Billings, Bowman, Dunn, Golden Valley, Hettinger and 3 more	86 min

Nearby

Severe Thunderstorm Watches in North Dakota, 2026 Every severe thunderstorm watch 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; radar from the NEXRAD Level II archive.