Alert archive / Colorado / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 55, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 11, 1999, 2:54 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. It was in force for 51 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 11, 1999, 2:54 PM MDT (20:54 UTC)
- Expired
- Jun 11, 1999, 3:45 PM MDT
- In force
- 51 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Adams County, CO, Arapahoe County, CO, Denver County, CO
The radar
The Denver radar (KFTG), 4 km from the middle of the area, began a volume at 20:56 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 |
|---|---|---|---|
| Jun 11, 1:15 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 8.9 hours before the alert went out and 111 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
- 14 J/kg
- Mixed-layer CIN
- -267 J/kg
- Mixed-layer LCL
- 806 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 27 m²/s²
- 0-3 km storm-relative helicity
- 197 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 11, 2:15 PM MDT, 39 minutes earlier.
Area forecast discussion, Jun 11, 2:15 PM MDT, 39 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>In the hours before
Special weather statement, Jun 11, 11:15 AM MDT, 3 hours 39 minutes before
COZ030-032>050-120600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1115 AM MDT FRI JUN 11 1999 THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: SUFFICIENT LOW LEVEL MOISTURE REMAINS ACROSS THE FOOTHILLS AND PLAINS OF NORTHEAST COLORADO...WHILE AMPLE HEATING WILL ALLOW THE ATMOSPHERE TO BECOME STRONGLY UNSTABLE THIS AFTERNOON AND INTO THE EVENING. THERE WILL BE SOME ENERGY AVAILABLE IN THE UPPER LEVELS TO ENHANCE STORM DEVELOPMENT LATER THIS AFTERNOON AND EVENING. AT THIS TIME...WIND FLOW PATTERNS ARE NOT CONDUCIVE TO TORNADIC DEVELOPMENT... BUT LARGE HAIL IS POSSIBLE WITH STORMS TODAY. INITIAL DEVELOPMENT WILL AGAIN DEVELOP OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY MOVE OVER THE URBAN CORRIDOR DURING THE EARLY AFTERNOON AND LATE AFTERNOON AND EARLY EVENING OVER THE PLAINS. THE ATMOSPHERE IS A LITTLE DRIER OVER THE WYOMING AND COLORADO BORDER AREAS...INCLUDING THE FAR NORTHERN MOUNTAINS AND FOOTHILLS OF LARIMER COUNTY...AND EXTENDING OUT INTO WELD COUNTY. STORMS WILL BE LATER IN DEVELOPING AND WEAKER OVER THESE AREAS. SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING...MAINLY AFTER 2 PM. ENTREKIN
Special weather statement, Jun 11, 11:15 AM MDT, 3 hours 39 minutes before
COZ030-032>050-120600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1115 AM MDT FRI JUN 11 1999 THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: SUFFICIENT LOW LEVEL MOISTURE REMAINS ACROSS THE FOOTHILLS AND PLAINS OF NORTHEAST COLORADO...WHILE AMPLE HEATING WILL ALLOW THE ATMOSPHERE TO BECOME STRONGLY UNSTABLE THIS AFTERNOON AND INTO THE EVENING. THERE WILL BE SOME ENERGY AVAILABLE IN THE UPPER LEVELS TO ENHANCE STORM DEVELOPMENT LATER THIS AFTERNOON AND EVENING. AT THIS TIME...WIND FLOW PATTERNS ARE NOT CONDUCIVE TO TORNADIC DEVELOPMENT... BUT LARGE HAIL IS POSSIBLE WITH STORMS TODAY. INITIAL DEVELOPMENT WILL AGAIN DEVELOP OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY MOVE OVER THE URBAN CORRIDOR DURING THE EARLY AFTERNOON AND LATE AFTERNOON AND EARLY EVENING OVER THE PLAINS. THE ATMOSPHERE IS A LITTLE DRIER OVER THE WYOMING AND COLORADO BORDER AREAS...INCLUDING THE FAR NORTHERN MOUNTAINS AND FOOTHILLS OF LARIMER COUNTY...AND EXTENDING OUT INTO WELD COUNTY. STORMS WILL BE LATER IN DEVELOPING AND WEAKER OVER THESE AREAS. SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING...MAINLY AFTER 2 PM. ENTREKIN
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 10, 6:00 PM MDT | Tornado Warning | BOU | Adams, Arapahoe, Washington | 30 min |
| Jun 10, 6:23 PM MDT | Tornado Warning | BOU | Washington | 37 min |
| Jun 10, 6:59 PM MDT | Tornado Warning | BOU | Washington | 31 min |
| Jun 10, 7:28 PM MDT | Severe Thunderstorm Warning | BOU | Washington | 47 min |
| Jun 11, 1:01 PM MDT | Severe Thunderstorm Warning | BOU | Douglas, Elbert | 44 min |
| Jun 11, 1:42 PM MDT | Severe Thunderstorm Warning | BOU | Douglas, Elbert | 48 min |
| Jun 11, 1:50 PM MDT | Tornado Warning | BOU | Elbert | 25 min |
| Jun 11, 2:26 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Douglas | 34 min |
| Jun 11, 2:36 PM MDT | Severe Thunderstorm Warning | BOU | Douglas, Elbert | 39 min |
| Jun 11, 3:14 PM MDT | Severe Thunderstorm Warning | BOU | Elbert | 46 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 1999Every severe thunderstorm warning in 1999
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.