Alert archive / Colorado / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 21, NWS Denver/Boulder, CO

May 21, 2026Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 21, 2026, 6:30 PM MDT for Washington County, Colorado. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 21, 2026, 6:30 PM MDT (00:30 UTC)
Expired: May 21, 2026, 7:00 PM MDT
In force: 30 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Damage threat: Considerable
Hail: 2.0 in
Wind: 60.0 mph

County Washington County, CO

The radar

The Goodland radar (KGLD), 112 km from the middle of the area, began a volume at 00:31 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 21, 2:55 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.5 hours before the alert went out and 264 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1093 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 149 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

326 
WUUS55 KBOU 220030
SVRBOU
COC121-220100-
/O.NEW.KBOU.SV.W.0021.260522T0030Z-260522T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
630 PM MDT Thu May 21 2026

The National Weather Service in Denver has issued a

* Severe Thunderstorm Warning for...
  Southeastern Washington County in northeastern Colorado...

* Until 700 PM MDT.

* At 630 PM MDT, a severe thunderstorm was located 12 miles south of
  Arickaree School, or 41 miles south of Akron, moving east at 15
  mph.

  HAZARD...Two inch hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail
           damage to roofs, siding, windows, and vehicles. Expect
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Mainly rural areas of Southeastern Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Anyone outdoors should move to shelter inside a well-built structure
and stay away from windows. This storm is capable of producing
dangerous hail and damaging winds.

&&

LAT...LON 3957 10309 3963 10308 3964 10280 3957 10280
TIME...MOT...LOC 0030Z 279DEG 13KT 3958 10302

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...2.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

63

1 follow-up statement

334 
WWUS55 KBOU 220042
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
642 PM MDT Thu May 21 2026

COC121-220100-
/O.CON.KBOU.SV.W.0021.000000T0000Z-260522T0100Z/
Washington CO-
642 PM MDT Thu May 21 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 7 PM MDT FOR
SOUTHEASTERN WASHINGTON COUNTY...

At 642 PM MDT, a severe thunderstorm was located 9 miles southwest of
Cope, or 43 miles south of Akron, moving east at 15 mph.

HAZARD...Two inch hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail
         damage to roofs, siding, windows, and vehicles. Expect wind
         damage to roofs, siding, and trees.

Locations impacted include...
  Mainly rural areas of Southeastern Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Anyone outdoors should move to shelter inside a well-built structure
and stay away from windows. This storm is capable of producing
dangerous hail and damaging winds.

&&

LAT...LON 3957 10308 3963 10306 3964 10280 3957 10280
TIME...MOT...LOC 0030Z 279DEG 13KT 3958 10302

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...2.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

63

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 21, 6:05 PM MDT	Tornado Warning	BOU	Logan	28 min
May 21, 6:25 PM MDT	Severe Thunderstorm Warning	BOU	Washington	35 min
May 21, 6:51 PM MDT	Flash Flood Warning	BOU	Washington	6 hr
May 21, 7:01 PM MDT	Severe Thunderstorm Warning	BOU	Washington	18 min
May 21, 7:09 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Adams, Arapahoe, Washington	36 min
May 21, 7:26 PM MDT	Special Weather Statement	BOU	Elbert	49 min
May 21, 7:57 PM MDT	Special Weather Statement	BOU	Lincoln	48 min
May 21, 8:39 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Lincoln	36 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2026 Every severe thunderstorm warning 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.