Alert archive / Colorado / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 113, NWS Denver/Boulder, CO

June 21, 2026Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 21, 2026, 8:43 PM MDT for Washington County, Colorado. It was in force for 32 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: Jun 21, 2026, 8:43 PM MDT (02:43 UTC)
Expired: Jun 21, 2026, 9:15 PM MDT
In force: 32 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.5 in
Wind: 60.0 mph

County Washington County, CO

The radar

The Denver radar (KFTG), 106 km from the middle of the area, began a volume at 02:47 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 2.7 hours before the alert went out and 261 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: 709 J/kg
Mixed-layer CIN: -97 J/kg
Mixed-layer LCL: 1003 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

623 
WUUS55 KBOU 220243
SVRBOU
COC121-220315-
/O.NEW.KBOU.SV.W.0113.260622T0243Z-260622T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
843 PM MDT Sun Jun 21 2026

The National Weather Service in Denver has issued a

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

* Until 915 PM MDT.

* At 843 PM MDT, a severe thunderstorm was located 8 miles south of
  Midway, or 12 miles west of Akron, moving east at 20 mph.

  HAZARD...Ping pong ball size 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...
  Akron, Midway and Fremont Butte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

&&

LAT...LON 4000 10348 4001 10347 4025 10347 4025 10314
      4000 10314
TIME...MOT...LOC 0243Z 267DEG 17KT 4011 10343

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

63

2 follow-up statements

436 
WWUS55 KBOU 220254
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
854 PM MDT Sun Jun 21 2026

COC121-220315-
/O.CON.KBOU.SV.W.0113.000000T0000Z-260622T0315Z/
Washington CO-
854 PM MDT Sun Jun 21 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM MDT FOR
CENTRAL WASHINGTON COUNTY...

At 854 PM MDT, a severe thunderstorm was located 8 miles south of
Midway, or 8 miles west of Akron, moving east at 20 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

Locations impacted include...
  Akron, Midway and Fremont Butte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

&&

LAT...LON 4000 10348 4001 10347 4025 10347 4025 10314
      4000 10314
TIME...MOT...LOC 0243Z 267DEG 17KT 4011 10343

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

63

896 
WWUS55 KBOU 220312
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
912 PM MDT Sun Jun 21 2026

COC121-220322-
/O.EXP.KBOU.SV.W.0113.000000T0000Z-260622T0315Z/
Washington CO-
912 PM MDT Sun Jun 21 2026

...SEVERE THUNDERSTORM WARNING WILL EXPIRE AT 915 PM MDT FOR CENTRAL
WASHINGTON COUNTY...

The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However, small
hail, gusty winds, and heavy rain are still possible with this
thunderstorm.

&&

LAT...LON 4000 10348 4001 10347 4025 10347 4025 10314
      4000 10314
TIME...MOT...LOC 0254Z 267DEG 17KT 4011 10336

$$

63

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 21, 5:59 PM MDT, 2 hours 44 minutes earlier. Its key messages:

Strong to severe storms possible across the far eastern plains today with large hail, gusty winds, and brief landspouts.
Increasing coverage of afternoon thunderstorms early to mid week, with continued potential for severe thunderstorms, especially in the plains.
Smoke aloft from the wildfires in Utah will bring intermittent hazy skies.
Elevated fire weather conditions will persist through much of the week in the high country.

Area forecast discussion, Jun 21, 5:59 PM MDT, 2 hours 44 minutes before

Area Forecast Discussion
National Weather Service Denver/Boulder CO
559 PM MDT Sun Jun 21 2026

.KEY MESSAGES...

- Strong to severe storms possible across the far eastern plains
  today with large hail, gusty winds, and brief landspouts.

- Increasing coverage of afternoon thunderstorms early to mid
  week, with continued potential for severe thunderstorms,
  especially in the plains.

- Smoke aloft from the wildfires in Utah will bring intermittent
  hazy skies.

- Elevated fire weather conditions will persist through much of
  the week in the high country.

&&

.DISCUSSION /Through Sunday/...
Issued at 231 PM MDT Sun Jun 21 2026

A weak shortwave will graze northeast Colorado this afternoon,
bringing the potential for scattered showers and thunderstorm
activity. Current radar imagery shows showers and strong
thunderstorms starting to develop over eastern Colorado where SBCAPE
values are already in the 1000-2000 J/kg range. Dewpoint values over
the Denver area have plummeted from the mid 50s to the mid 30s due
to the mixing of drier dewpoints aloft. Therefore, the better
surface moisture for today's convective potential will be over the
easternmost counties of our CWA, where a Severe Thunderstorm Watch
is in effect until 8pm. Modest shear (30-40KT 0-6km) and steep mid-
level lapse rates will be conducive to a few strong supercells that
could produce very large hail, gusty winds, and brief landspouts.

There will be daily chances for severe thunderstorms through at
least Thursday this week, given the generally weak and zonal flow
aloft combined with low-level moisture advection from the southeast.
However, tomorrow looks to be the best chance for a more widespread
thunderstorm threat due to the better shear in place as well as 0-
3km SRH values in the 100-300 m^2/s^2 range over the northeastern CO
plains. Additionally, precipitable water values east of the
mountains will exceed the 75th percentile of climatology, with
values exceeding the 90th percentile at times (0.80"-1.00"). Large
hail, gusty winds, and landspouts will be possible again with any
strong thunderstorms that develop tomorrow afternoon and early
evening.

A cold front will advance through the region early Tuesday morning,
keeping afternoon temperatures in the low 80s for the lower
elevations. Isolated showers and thunderstorms will be possible
Tuesday afternoon if any low stratus behind the front are able to
clear off early enough for convective initiation to occur.

Long-range ensembles indicate a warming and drying trend arriving
late this week. While it is too early to tell with certainty,
widespread elevated to critical fire weather conditions appear to
return on Saturday as RHs drop into the teens and the pressure
gradient tightens due to a closed upper level low sliding through
the Pacific Northwest.

&&

.AVIATION /00Z TAFS through 00Z Tuesday/...
Issued at 555 PM MDT Sun Jun 21 2026

The current radar as of 1750z shows an outflow boundary located
just to the east of the KDEN property moving to the west. This
boundary will likely cause erratic and gusty winds over the next
few hours at KDEN with gusts of 25 to 30 kts possible.
Additionally, isolated thunderstorms have been firing off to the
east of this boundary for the last hour or two. Thunderstorms
remain possible in the vicinity of all three sites, particularly
KAPA and KDEN, until about 02z tonight.

Winds should then settle down some and stay in a more NNE/NE
direction before turning to near drainage early tomorrow morning.
The NE winds could bring in some lower clouds to about 5000 feet
(possible IFR to MVFR conditions) with even the possibility for
some briefly patchy fog. Wildfire smoke could also return tomorrow
morning between 06z and 12z as well as tomorrow evening after
00z, potentially impacting slantwise visibility at times, but
currently looks to have minimal near surface impacts.
Additionally, a cyclone could form early tomorrow morning, but
confidence is low on this solution at this time.

Tomorrow afternoon should be similar to this afternoon with
strong NW winds gusting to about 20 kts by about 18z to 19z. A
boundary along the Palmer Divide will be the initial focus for
thunderstorm development before spreading northward later in the
afternoon. There is now enough confidence to include VCTS at all
three sites with a prob30 for -tsra and some stronger wind gusts
at KDEN and KAPA for most of tomorrow afternoon. The showers and
thunderstorms should likely clear to the east of the sites by
about 00z tomorrow evening with strong winds still in place for at
least a few hours.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...AA
AVIATION...MV

In the hours before

Special weather statement, Jun 21, 6:22 PM MDT, 2 hours 21 minutes before

Special Weather Statement
National Weather Service Denver CO
622 PM MDT Sun Jun 21 2026

COZ044-048-049-220100-
Washington County CO-Logan County CO-Morgan County CO-
622 PM MDT Sun Jun 21 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN MORGAN...
SOUTHWESTERN LOGAN AND NORTH CENTRAL WASHINGTON COUNTIES UNTIL 7 PM
MDT...

At 622 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Hillrose, or 17 miles northeast of Fort Morgan, moving
east at 20 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Merino, Hillrose, Prewitt Reservoir, Snyder, Messex, Union and
  Fremont Butte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 4033 10374 4052 10365 4052 10358 4054 10358
      4047 10314 4022 10325
TIME...MOT...LOC 0022Z 283DEG 18KT 4043 10355

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

63

Special weather statement, Jun 21, 7:03 PM MDT, 1 hour 40 minutes before

Special Weather Statement
National Weather Service Denver CO
703 PM MDT Sun Jun 21 2026

COZ048-049-220130-
Washington County CO-Logan County CO-
703 PM MDT Sun Jun 21 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LOGAN AND
NORTHEASTERN WASHINGTON COUNTIES UNTIL 730 PM MDT...

At 703 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Sterling, moving east at 25 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Eastern Sterling, Burdett, St Petersburg, Lone Star and Reiradon
  Hill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 4038 10324 4064 10319 4062 10275 4044 10277
      4044 10278 4035 10278 4035 10279 4032 10279
TIME...MOT...LOC 0103Z 279DEG 22KT 4052 10310

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

63

Local storm report, Jun 21, 7:31 PM MDT, 1 hour 12 minutes before

Preliminary Local Storm Report
National Weather Service Denver CO
731 PM MDT Sun Jun 21 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0730 PM     Hail             5 SSE Reiradon Hill     40.51N 102.99W
06/21/2026  E1.00 Inch       Logan              CO   Trained Spotter

&&

KEB

Local storm report, Jun 21, 7:36 PM MDT, 1 hour 7 minutes before

Preliminary Local Storm Report
National Weather Service Denver CO
736 PM MDT Sun Jun 21 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0730 PM     Hail             4 SE Reiradon Hill      40.53N 102.99W
06/21/2026  M1.75 Inch       Logan              CO   Trained Spotter

&&

KEB

Local storm report, Jun 21, 8:04 PM MDT, 39 minutes before

Preliminary Local Storm Report
National Weather Service Denver CO
804 PM MDT Sun Jun 21 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0743 PM     Hail             1 SW St Petersburg      40.54N 102.84W
06/21/2026  E2.75 Inch       Logan              CO   Trained Spotter

&&

KEB

Local storm report, Jun 21, 8:42 PM MDT, 1 minute before

Preliminary Local Storm Report
National Weather Service Denver CO
842 PM MDT Sun Jun 21 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0835 PM     Hail             3 ENE Highland Center   40.55N 102.52W
06/21/2026  M2.00 Inch       Phillips           CO   Storm Chaser

&&

KEB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 6:22 PM MDT	Special Weather Statement	BOU	Morgan	38 min
Jun 21, 7:03 PM MDT	Special Weather Statement	BOU	Logan	27 min
Jun 21, 7:13 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Washington	32 min
Jun 21, 7:44 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan, Phillips	31 min
Jun 21, 8:16 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Phillips	29 min
Jun 21, 8:44 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	29 min
Jun 21, 9:14 PM MDT	Special Weather Statement	BOU	Adams	31 min
Jun 21, 9:17 PM MDT	Special Weather Statement	BOU	Boulder	28 min
Jun 21, 9:30 PM MDT	Severe Thunderstorm Warning	BOU	Boulder	30 min
Jun 22, 12:02 AM MDT	Fire Weather Watch	BOU	Boulder, Clear Creek, Gilpin, Grand, Jackson, Park and 1 more	12 hr
Jun 22, 12:18 PM MDT	Red Flag Warning	BOU	Boulder, Clear Creek, Gilpin, Grand, Jackson, Park and 1 more	32 hr
Jun 22, 3:12 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Weld	48 min
Jun 22, 3:48 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan	42 min
Jun 22, 4:04 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Weld	41 min
Jun 22, 4:21 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan	39 min
Jun 22, 4:38 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan, Weld	40 min
Jun 22, 4:51 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan	39 min
Jun 22, 5:04 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan, Morgan	26 min
Jun 22, 5:22 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan, Washington	45 min
Jun 22, 5:29 PM MDT	Tornado Warning	BOU	Logan, Washington	31 min
Jun 22, 5:54 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Washington	51 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.