Alert archive / Colorado / Severe Thunderstorm Warnings in 2024
Severe Thunderstorm Warning 229, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 11, 2024, 5:41 PM MDT for Adams County, Weld County, Colorado. It was in force for 31 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
- Aug 11, 2024, 5:41 PM MDT (23:41 UTC)
- Expired
- Aug 11, 2024, 6:12 PM MDT
- In force
- 31 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Adams County, CO, Weld County, CO
The radar
The Denver radar (KFTG), 50 km from the middle of the area, began a volume at 23:45 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 nearest sounding before it
N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.7 hours before the alert went out and 333 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 952 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 94 m²/s²
- 0-3 km storm-relative helicity
- 249 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Aug 11, 5:38 PM MDT, 3 minutes earlier.
Area forecast discussion, Aug 11, 5:38 PM MDT, 3 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, Aug 11, 10:59 AM MDT, 6 hours 42 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1059 AM MDT Sun Aug 11 2024 COZ030>051-121700- 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- 1059 AM MDT Sun Aug 11 2024 This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Scattered thunderstorms are expected to redevelop over the mountains by early afternoon and then spread and develop eastward across the plains through the late afternoon hours. A couple storms will likely become severe, mainly along and east of a Sterling to Akron to Limon line where more instability exists. The main threat is damaging wind gusts to around 60 mph, but large hail is also possible. The recent burn scars will see a limited threat of flash flooding, as storms will be moving along and intensity of storms in/near the mountains is expected to be a little less than yesterday. Storms will diminish from northwest to southeast across the area this evening. .DAYS TWO THROUGH SEVEN...Monday through Saturday Scattered to numerous showers and storms are expected to start the week, most numerous over the high country and Palmer Divide. Locally heavy rainfall is possible with the stronger storms that could elevate the flash flood threat for sensitive areas like our burn scars. A couple of storms could become severe Monday and Monday evening with possibly a higher threat on Tuesday. There will be a gradual warming and drying trend Wednesday through Friday, with thunderstorm activity returning to a more typical summer convective pattern as the week persists. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight. However, any reports of heavy rainfall, strong wind gusts, or hail will be appreciated.
In the hours before
Local storm report, Aug 11, 12:49 PM MDT, 4 hours 52 minutes before
Preliminary Local Storm Report
National Weather Service Denver CO
1249 PM MDT Sun Aug 11 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0238 PM Flash Flood 2 WNW Cedar Cove 40.42N 105.29W
08/07/2024 Larimer CO NWS Employee
Delayed Report: Several rocks laying across
Hwy 34, right off the Alexander Mountain
burn scar.
&&
GHSpecial weather statement, Aug 11, 1:36 PM MDT, 4 hours 5 minutes before
Special Weather Statement
National Weather Service Denver CO
136 PM MDT Sun Aug 11 2024
COZ038-042-048-112015-
Logan County CO-Northeast Weld County CO-
Larimer County Below 6000 Feet/Northwest Weld County CO-
136 PM MDT Sun Aug 11 2024
...STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN WELD AND WEST
CENTRAL LOGAN COUNTIES THROUGH 215 PM MDT...
At 136 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms along a line extending from 13 miles northeast of
Pawnee Buttes to 6 miles southwest of Panorama Point to 4 miles
southwest of Hereford, or along a line extending from 19 miles
southwest of Kimball to 50 miles north of Fort Morgan to 27 miles
southeast of Cheyenne. Movement was southeast at 30 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Grover, New Raymer, Keota, Hereford, Stoneham, and Pawnee Buttes.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4067 10332 4059 10376 4059 10430 4096 10449
4100 10410 4100 10376
TIME...MOT...LOC 1936Z 322DEG 24KT 4099 10387 4095 10412 4092 10435
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
HEAVENERSpecial weather statement, Aug 11, 2:21 PM MDT, 3 hours 20 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, Aug 11, 2:27 PM MDT, 3 hours 14 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>Local storm report, Aug 11, 3:20 PM MDT, 2 hours 21 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, Aug 11, 5:15 PM MDT, 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>The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 9:57 PM MDT | Areal Flood Advisory | BOU | Douglas, Elbert | 3 hr |
| Aug 11, 2:21 PM MDT | Special Weather Statement | BOU | Logan | 39 min |
| Aug 11, 2:27 PM MDT | Special Weather Statement | BOU | Weld | 48 min |
| Aug 11, 2:41 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 49 min |
| Aug 11, 3:23 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Phillips | 21 min |
| Aug 11, 5:15 PM MDT | Special Weather Statement | BOU | Broomfield | 45 min |
| Aug 11, 5:56 PM MDT | Special Weather Statement | BOU | Morgan | 49 min |
| Aug 11, 5:59 PM MDT | Special Weather Statement | BOU | Denver | 46 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 2024Every severe thunderstorm warning in 2024
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.