Alert archive / Colorado / Special Weather Statements in 2021
Special Weather Statement, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this special weather statement at May 17, 2021, 1:40 PM MDT for Broomfield County, Colorado. It was in force for 50 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
- May 17, 2021, 1:40 PM MDT (19:40 UTC)
- Expired
- May 17, 2021, 2:30 PM MDT
- In force
- 50 min
- Issued by
- NWS Denver/Boulder, CO
County Broomfield County, CO
The radar
The Denver radar (KFTG), 68 km from the middle of the area, began a volume at 19:43 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
Denver, CO (KDNR), launched 12:00Z, 7.7 hours before the alert went out and 169 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
- 44 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 779 m above ground
- 0-6 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- -7 m²/s²
- 0-3 km storm-relative helicity
- 12 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement 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 special weather statement went out at May 17, 10:50 AM MDT, 2 hours 50 minutes earlier.
Area forecast discussion, May 17, 10:50 AM MDT, 2 hours 50 minutes before
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<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.
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If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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</html>Hazardous weather outlook, May 17, 10:59 AM MDT, 2 hours 41 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1059 AM MDT Mon May 17 2021 COZ030>051-181700- 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 Mon May 17 2021 This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Scattered thunderstorms will develop over the mountains and Palmer Divide by midday, and spread onto the plains after 2 pm and continue into the evening hours. The main threats are heavy rain and the potential for flash flooding. Across the far eastern plains and Palmer Divide, there is a slight chance of severe weather with hail up to one inch in diameter. There is also a low to moderate threat of flash flooding from thunderstorm rains in the foothills burn areas. Mainly from 2 to 5 pm this afternoon in Boulder and Larimer counties. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Scattered showers and thunderstorms will develop Tuesday with less coverage on Wednesday. The severe thunderstorm and flood threat will be low both days. A warm and windy pattern will develop Thursday into next weekend. There will be a chance for showers and storms during each afternoon and evening. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated today or tonight.
In the hours before
Special weather statement, May 17, 1:40 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Denver CO
140 PM MDT Mon May 17 2021
COZ039-043-172030-
Central and South Weld County CO-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County
CO-
140 PM MDT Mon May 17 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN BOULDER COUNTY UNTIL
230 PM MDT...
At 139 PM MDT, Doppler radar was tracking a strong thunderstorm near
Longmont, or 24 miles southwest of Greeley, moving northwest at 5
mph.
Half inch hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Northeastern Boulder, Longmont, Erie, Firestone, Frederick, Mead and
Niwot.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle.
&&
LAT...LON 4017 10491 4003 10505 4012 10531 4014 10531
4014 10529 4015 10528 4016 10529 4017 10528
4020 10527 4026 10520 4026 10506 4029 10506
TIME...MOT...LOC 1939Z 126DEG 5KT 4015 10506
HANSONThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 6:47 PM MDT | Special Weather Statement | BOU | Lincoln | 28 min |
| May 16, 7:39 PM MDT | Special Weather Statement | BOU | Lincoln | 36 min |
| May 17, 12:39 PM MDT | Areal Flood Advisory | BOU | Larimer | 81 min |
| May 17, 2:22 PM MDT | Areal Flood Advisory | BOU | Grand | 113 min |
| May 17, 3:45 PM MDT | Areal Flood Advisory | BOU | Boulder | 75 min |
| May 17, 3:49 PM MDT | Special Weather Statement | BOU | Boulder | 41 min |
| May 17, 4:23 PM MDT | Special Weather Statement | BOU | Jefferson | 37 min |
| May 17, 4:43 PM MDT | Special Weather Statement | BOU | Jefferson | 47 min |
| May 17, 4:54 PM MDT | Areal Flood Advisory | BOU | Jefferson | 3 hr |
Nearby
Special Weather Statements in Colorado, 2021Every special weather statement in 2021
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.