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 15, 2021, 2:21 PM MDT for Larimer County, Colorado. It was in force for 24 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 15, 2021, 2:21 PM MDT (20:21 UTC)
- Expired
- May 15, 2021, 2:45 PM MDT
- In force
- 24 min
- Issued by
- NWS Denver/Boulder, CO
County Larimer County, CO
The radar
The Cheyenne radar (KCYS), 88 km from the middle of the area, began a volume at 20:25 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, 8.4 hours before the alert went out and 248 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
- 21 J/kg
- Mixed-layer CIN
- -326 J/kg
- Mixed-layer LCL
- 769 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 48 m²/s²
- 0-3 km storm-relative helicity
- 74 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
552
WWUS85 KBOU 152021
SPSBOU
Special Weather Statement
National Weather Service Denver CO
221 PM MDT Sat May 15 2021
COZ033-035-152045-
Larimer and Boulder Counties Between 6000 and 9000 Feet CO-
South and East Jackson/Larimer/North and Northeast Grand/Northwest
Boulder Counties Above 9000 Feet CO-
221 PM MDT Sat May 15 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN LARIMER COUNTY UNTIL
245 PM MDT...
At 221 PM MDT, Doppler radar was tracking a strong thunderstorm over
Four Corners, or 34 miles southwest of Laramie, moving northeast at
15 mph.
Penny size hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Four Corners.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4100 10571 4089 10560 4076 10589 4093 10605
4100 10591
TIME...MOT...LOC 2021Z 241DEG 14KT 4088 10590
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 14, 6:49 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 41 min |
| May 14, 6:52 PM MDT | Special Weather Statement | BOU | Morgan | 38 min |
| May 14, 7:17 PM MDT | Severe Thunderstorm Warning | BOU | Morgan, Washington | 28 min |
| May 14, 7:36 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 39 min |
| May 14, 7:40 PM MDT | Severe Thunderstorm Warning | BOU | Morgan, Washington | 50 min |
| May 14, 8:14 PM MDT | Severe Thunderstorm Warning | BOU | Morgan, Weld | 46 min |
| May 14, 8:52 PM MDT | Severe Thunderstorm Warning | BOU | Morgan | 38 min |
| May 14, 9:29 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Morgan, Washington | 46 min |
| May 15, 2:50 PM MDT | Special Weather Statement | BOU | Denver | 25 min |
| May 15, 5:29 PM MDT | Special Weather Statement | BOU | Douglas | 31 min |
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.