Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 62, NWS Denver/Boulder, CO

June 7, 2021Larimer County, Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 7, 2021, 6:25 PM MDT for Larimer County, Weld County, Colorado. It was in force for 39 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: Jun 7, 2021, 6:25 PM MDT (00:25 UTC)
Expired: Jun 7, 2021, 7:04 PM MDT
In force: 39 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Larimer County, CO, Weld County, CO

The radar

The Cheyenne radar (KCYS), 72 km from the middle of the area, began a volume at 00:25 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 00:00Z, 0.4 hours before the alert went out and 157 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 7 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 3658 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

604 
WUUS55 KBOU 080025
SVRBOU
COC069-123-080115-
/O.NEW.KBOU.SV.W.0062.210608T0025Z-210608T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
625 PM MDT Mon Jun 7 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  West central Weld County in northeastern Colorado...
  East central Larimer County in north central Colorado...

* Until 715 PM MDT.

* At 625 PM MDT, a severe thunderstorm was located over Windsor, or 9
  miles southeast of Fort Collins, moving north at 15 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees. Hail damage to 
           vehicles is expected.

* Locations impacted include...
  Eastern Fort Collins, Greeley, northeastern Loveland, Windsor,
  Evans, Milliken, Eaton, Severance, Ault and Timnath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. This storm may cause serious injury and significant
property damage.

&&

LAT...LON 4035 10488 4047 10511 4067 10500 4069 10487
      4060 10472 4039 10473
TIME...MOT...LOC 0025Z 192DEG 15KT 4046 10495 

HAIL...1.00IN
WIND...60MPH
 
$$

RJK

2 follow-up statements

818 
WWUS55 KBOU 080055
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
655 PM MDT Mon Jun 7 2021

COC069-123-080115-
/O.CON.KBOU.SV.W.0062.000000T0000Z-210608T0115Z/
Weld CO-Larimer CO-
655 PM MDT Mon Jun 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM MDT
FOR WEST CENTRAL WELD AND EAST CENTRAL LARIMER COUNTIES...

At 654 PM MDT, a severe thunderstorm was located 4 miles northwest of
Severance, or 8 miles east of Fort Collins, moving north at 15 mph.

The largest hail reported with the storm so far has been one half 
inch.   

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees. Hail damage to 
         vehicles is expected.

Locations impacted include...
Eastern Fort Collins, northern Greeley, Windsor, Severance, Ault and
Timnath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. This storm may cause serious injury and significant
property damage.

&&

LAT...LON 4046 10493 4052 10507 4067 10500 4069 10487
      4060 10472 4046 10477
TIME...MOT...LOC 0054Z 192DEG 15KT 4058 10492 

HAIL...1.00IN
WIND...60MPH
 
$$

RJK

929 
WWUS55 KBOU 080104
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
704 PM MDT Mon Jun 7 2021

COC069-123-080114-
/O.CAN.KBOU.SV.W.0062.000000T0000Z-210608T0115Z/
Weld CO-Larimer CO-
704 PM MDT Mon Jun 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL WELD AND EAST
CENTRAL LARIMER COUNTIES IS CANCELLED...
                
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 has been cancelled.


LAT...LON 4046 10493 4052 10507 4067 10500 4069 10487
      4060 10472 4046 10477
TIME...MOT...LOC 0102Z 192DEG 15KT 4062 10491 

$$

RJK

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 7, 6:04 PM MDT	Special Weather Statement	BOU	Weld	26 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2021 Every 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.