Alert archive / Colorado / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 101, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 4, 2021, 12:37 PM MDT for Larimer County, Colorado. It was in force for 38 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
- Jul 4, 2021, 12:37 PM MDT (18:37 UTC)
- Expired
- Jul 4, 2021, 1:15 PM MDT
- In force
- 38 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 50.0 mph
County Larimer County, CO
The radar
The Cheyenne radar (KCYS), 47 km from the middle of the area, began a volume at 18:40 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, 6.6 hours before the alert went out and 212 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
- 204 J/kg
- Mixed-layer CIN
- -314 J/kg
- Mixed-layer LCL
- 2162 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 35 m²/s²
- 0-3 km storm-relative helicity
- 80 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
550
WUUS55 KBOU 041837
SVRBOU
COC069-041915-
/O.NEW.KBOU.SV.W.0101.210704T1837Z-210704T1915Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
1237 PM MDT Sun Jul 4 2021
The National Weather Service in Denver Colorado has issued a
* Severe Thunderstorm Warning for...
Northeastern Larimer County in north central Colorado...
* Until 115 PM MDT.
* At 1236 PM MDT, a severe thunderstorm was located near Virginia
Dale, or 26 miles south of Laramie, moving east at 15 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
* Locations impacted include...
Virginia Dale.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
If on or near a lake, get away from the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 15 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4100 10519 4083 10520 4083 10548 4099 10550
4100 10522
TIME...MOT...LOC 1836Z 269DEG 13KT 4095 10540
HAIL...1.00IN
WIND...<50MPH
$$
COOPER1 follow-up statement
517
WWUS55 KBOU 041908
SVSBOU
Severe Weather Statement
National Weather Service Denver CO
108 PM MDT Sun Jul 4 2021
COC069-041917-
/O.EXP.KBOU.SV.W.0101.000000T0000Z-210704T1915Z/
Larimer CO-
108 PM MDT Sun Jul 4 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LARIMER COUNTY
WILL EXPIRE AT 115 PM MDT...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However small
hail, gusty winds and heavy rain are still possible with this
thunderstorm, as well as others over northern Larimer County.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Denver Colorado.
LAT...LON 4100 10519 4083 10520 4083 10548 4099 10550
4100 10522
TIME...MOT...LOC 1907Z 269DEG 13KT 4095 10527
$$
COOPERThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 3, 6:00 PM MDT | Flash Flood Warning | BOU | Logan | 2 hr |
| Jul 3, 6:01 PM MDT | Areal Flood Advisory | BOU | Washington | 89 min |
| Jul 3, 6:14 PM MDT | Special Weather Statement | BOU | Sedgwick | 31 min |
| Jul 3, 7:26 PM MDT | Special Weather Statement | BOU | Lincoln | 34 min |
| Jul 4, 10:34 AM MDT | Areal Flood Advisory | BOU | Larimer | 86 min |
| Jul 4, 11:54 AM MDT | Areal Flood Advisory | BOU | Larimer | 81 min |
| Jul 4, 12:10 PM MDT | Special Weather Statement | BOU | Larimer | 50 min |
| Jul 4, 12:28 PM MDT | Areal Flood Advisory | BOU | Larimer | 77 min |
| Jul 4, 1:51 PM MDT | Areal Flood Advisory | BOU | Larimer | 75 min |
| Jul 4, 2:49 PM MDT | Special Weather Statement | BOU | Denver | 26 min |
| Jul 4, 3:20 PM MDT | Flash Flood Warning | BOU | Larimer | 85 min |
| Jul 4, 3:31 PM MDT | Areal Flood Advisory | BOU | Douglas | 119 min |
| Jul 4, 3:56 PM MDT | Areal Flood Advisory | BOU | Elbert | 53 min |
| Jul 4, 4:28 PM MDT | Special Weather Statement | BOU | Adams, Arapahoe | 62 min |
| Jul 4, 4:43 PM MDT | Special Weather Statement | BOU | Elbert | 62 min |
| Jul 4, 5:42 PM MDT | Special Weather Statement | BOU | Douglas | 48 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.