Alert archive / Colorado / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 152, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Sep 11, 2021, 7:04 PM MDT for Logan County, Colorado. It was in force for 26 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
- Sep 11, 2021, 7:04 PM MDT (01:04 UTC)
- Expired
- Sep 11, 2021, 7:30 PM MDT
- In force
- 26 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Hail
- 0.75 in
- Wind
- 70.0 mph
County Logan County, CO
The radar
The Cheyenne radar (KCYS), 148 km from the middle of the area, began a volume at 01:03 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 00:00Z, 1.1 hours before the alert went out and 98 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
- 403 J/kg
- Mixed-layer CIN
- -128 J/kg
- Mixed-layer LCL
- 3631 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 139 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
678
WUUS55 KBOU 120104
SVRBOU
COC075-120130-
/O.NEW.KBOU.SV.W.0152.210912T0104Z-210912T0130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
704 PM MDT Sat Sep 11 2021
The National Weather Service in Denver Colorado has issued a
* Severe Thunderstorm Warning for...
Central Logan County in northeastern Colorado...
* Until 730 PM MDT.
* At 704 PM MDT, severe thunderstorms were located along a line
extending from 9 miles northeast of Westplains to near Atwood, or
along a line extending from 21 miles southeast of Kimball to 4
miles southwest of Sterling, moving northeast at 35 mph.
HAZARD...70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect considerable tree damage. Damage is likely to
mobile homes, roofs, and outbuildings.
* Locations impacted include...
Iliff.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Large hail and damaging winds and continuous cloud to ground
lightning is occurring with these storms. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.
&&
LAT...LON 4058 10296 4057 10335 4100 10344 4100 10296
TIME...MOT...LOC 0104Z 239DEG 29KT 4099 10342 4058 10327
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 11, 7:25 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 50 min |
| Sep 11, 8:04 PM MDT | Special Weather Statement | BOU | Sedgwick | 26 min |
| Sep 11, 8:14 PM MDT | Special Weather Statement | BOU | Denver | 16 min |
| Sep 11, 8:31 PM MDT | Special Weather Statement | BOU | Denver | 29 min |
| Sep 12, 3:38 PM MDT | Special Weather Statement | BOU | Elbert | 52 min |
| Sep 12, 4:16 PM MDT | Special Weather Statement | BOU | Lincoln | 29 min |
| Sep 12, 5:27 PM MDT | Severe Thunderstorm Warning | BOU | Lincoln | 33 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 2021Every severe thunderstorm warning 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.