Alert archive / Colorado / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 256, NWS Denver/Boulder, CO

July 21, 2026Grand County, Jackson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 21, 2026, 5:46 PM MDT for Grand County, Jackson County, Colorado. It was in force for 19 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 21, 2026, 5:46 PM MDT (23:46 UTC)
Expired: Jul 21, 2026, 6:05 PM MDT
In force: 19 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Grand County, CO, Jackson County, CO

The radar

The Cheyenne radar (KCYS), 147 km from the middle of the area, began a volume at 23:49 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 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 Jul 21, 1:13 PM MDT, 4 hours 33 minutes earlier.

Area forecast discussion, Jul 21, 1:13 PM MDT, 4 hours 33 minutes before

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In the hours before

Special weather statement, Jul 21, 3:20 PM MDT, 2 hours 26 minutes before

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<body>
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
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Special weather statement, Jul 21, 5:38 PM MDT, 8 minutes before

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<head>
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  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 3:20 PM MDT	Special Weather Statement	BOU	Clear Creek	25 min
Jul 21, 4:56 PM MDT	Areal Flood Advisory	BOU	Larimer	4 hr
Jul 21, 5:38 PM MDT	Special Weather Statement	BOU	Grand	37 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; radar from the NEXRAD Level II archive.