Alert archive / Colorado / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 222, NWS Denver/Boulder, CO

June 29, 2023Denver County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 29, 2023, 3:17 PM MDT for Denver County, Jefferson County, Colorado. It was in force for 43 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
Jun 29, 2023, 3:17 PM MDT (21:17 UTC)
Expired
Jun 29, 2023, 4:00 PM MDT
In force
43 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Denver County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 46 km from the middle of the area, began a volume at 21:18 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.

IssuedProductOfficeLasted
Jun 29, 1:17 PM MDTTornado WatchSPC8 hr

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 9.3 hours before the alert went out and 301 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-pSkew-T log-p diagram, Grand Junction, CO at 12:00Z on 2023-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2023-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
2750 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 29, 12:36 PM MDT, 2 hours 41 minutes earlier.

Area forecast discussion, Jun 29, 12:36 PM MDT, 2 hours 41 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Hazardous weather outlook, Jun 29, 11:03 AM MDT, 4 hours 14 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1103 AM MDT Thu Jun 29 2023

COZ030>051-301715-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
1103 AM MDT Thu Jun 29 2023

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Scattered thunderstorms will develop over and near the Front Range
this afternoon, and move onto the plains in the late afternoon and
evening. Some of the storms will be strong to severe and a Severe
Thunderstorm Watch will likely be needed. The main threat will be
along the I-25 corridor and eastward towards Akron and Sterling.
The strongest storms could produce hail up to baseball ball size
and wind gusts to 70 mph. A couple tornadoes are also possible.
There is a flash flood threat mainly in Morgan and Logan Counties
as well due to heavy rain.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Additional scattered to numerous showers and thunderstorms are
expected for Friday. The severe threat decreases as the main
threat shifts south and eastward. However, storm movement will be
slower, which will increase the threat for flash flooding of flood
prone areas.

Saturday will be drier, but an active weather pattern is expected
to resume Sunday and into next week. There may be a possible lull
in thunderstorm activity on Monday, but scattered afternoon and
evening thunderstorms are expected for Tuesday and Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed after 2 PM.

In the hours before

Local storm report, Jun 29, 10:51 AM MDT, 4 hours 26 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Jun 29, 1:28 PM MDT, 1 hour 49 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Jun 29, 1:39 PM MDT, 1 hour 38 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 28, 6:37 PM MDTSevere Thunderstorm WarningBOULogan, Weld38 min
Jun 28, 6:44 PM MDTTornado Warning Tornado observedBOULogan, Weld31 min
Jun 28, 7:05 PM MDTSpecial Weather StatementBOULogan25 min
Jun 28, 7:08 PM MDTTornado WarningBOULogan37 min
Jun 28, 7:34 PM MDTSevere Thunderstorm WarningBOULogan41 min
Jun 28, 7:41 PM MDTSpecial Weather StatementBOUSedgwick34 min
Jun 28, 8:02 PM MDTSevere Thunderstorm Warning Considerable damage threatBOULogan43 min
Jun 28, 8:36 PM MDTSevere Thunderstorm WarningBOULogan39 min
Jun 28, 8:39 PM MDTAreal Flood AdvisoryBOULogan3 hr
Jun 28, 8:51 PM MDTSevere Thunderstorm WarningBOULogan24 min
Jun 28, 9:04 PM MDTSevere Thunderstorm WarningBOULogan41 min
Jun 28, 9:19 PM MDTSevere Thunderstorm Warning Destructive damage threatBOULogan, Phillips41 min
Jun 28, 9:38 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan, Weld52 min
Jun 28, 9:43 PM MDTFlash Flood WarningBOULogan3 hr
Jun 28, 9:50 PM MDTAreal Flood AdvisoryBOUPhillips3 hr
Jun 28, 9:56 PM MDTSevere Thunderstorm Warning Considerable damage threatBOULogan, Phillips34 min
Jun 28, 10:07 PM MDTSevere Thunderstorm WarningBOULogan38 min
Jun 28, 10:09 PM MDTFlash Flood WarningBOUPhillips3 hr
Jun 28, 10:24 PM MDTSevere Thunderstorm WarningBOUWeld36 min
Jun 28, 10:26 PM MDTSevere Thunderstorm WarningBOUWeld34 min
Jun 28, 10:30 PM MDTSevere Thunderstorm Warning Destructive damage threatBOUPhillips45 min
Jun 28, 10:34 PM MDTSevere Thunderstorm WarningBOUMorgan26 min
Jun 28, 10:51 PM MDTFlash Flood WarningBOUPhillips3 hr
Jun 28, 10:53 PM MDTTornado WarningBOUMorgan37 min
Jun 28, 10:57 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUWeld33 min
Jun 28, 11:08 PM MDTTornado WarningBOUWashington37 min
Jun 28, 11:19 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan24 min
Jun 28, 11:27 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan, Weld33 min
Jun 28, 11:42 PM MDTTornado WarningBOUWashington33 min
Jun 28, 11:45 PM MDTAreal Flood AdvisoryBOUPhillips3 hr
Jun 28, 11:53 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan37 min
Jun 29, 12:01 AM MDTTornado WarningBOUMorgan29 min
Jun 29, 12:09 AM MDTSevere Thunderstorm Warning Considerable damage threatBOUWashington37 min
Jun 29, 12:26 AM MDTTornado WarningBOUMorgan, Washington34 min
Jun 29, 12:44 AM MDTSevere Thunderstorm WarningBOUMorgan31 min
Jun 29, 1:00 AM MDTSevere Thunderstorm Warning Considerable damage threatBOUWashington30 min
Jun 29, 1:19 AM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan41 min
Jun 29, 1:27 AM MDTSevere Thunderstorm WarningBOUWashington33 min
Jun 29, 1:28 PM MDTSpecial Weather StatementBOUGilpin47 min
Jun 29, 1:39 PM MDTSpecial Weather StatementBOUBoulder51 min
Jun 29, 3:30 PM MDTAreal Flood AdvisoryBOUAdams, Denver, Jefferson2 hr
Jun 29, 3:52 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Denver, Jefferson38 min
Jun 29, 4:07 PM MDTFlash Flood WarningBOUDenver, Jefferson113 min
Jun 29, 4:28 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver47 min
Jun 29, 5:08 PM MDTSevere Thunderstorm WarningBOUAdams24 min
Jun 29, 5:13 PM MDTSevere Thunderstorm Warning Destructive damage threatBOUAdams, Arapahoe47 min
Jun 29, 5:28 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUAdams, Arapahoe32 min
Jun 29, 5:41 PM MDTFlash Flood WarningBOUAdams3 hr
Jun 29, 5:42 PM MDTSevere Thunderstorm WarningBOUDouglas, Jefferson48 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2023Every severe thunderstorm warning in 2023

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.