Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 92, NWS Denver/Boulder, CO

July 2, 2021Adams County, Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 2, 2021, 6:42 PM MDT for Adams County, Weld County, Colorado. It was in force for 33 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 2, 2021, 6:42 PM MDT (00:42 UTC)
Expired: Jul 2, 2021, 7:15 PM MDT
In force: 33 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Adams County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 26 km from the middle of the area, began a volume at 00:42 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.

What was reported inside it

Time	Report	Where	Remark
Jul 2, 6:50 PM MDT	HAIL 1.25	2 Nw Barr Lake, CO	REPORT FROM MPING: HALF DOLLAR (1.25 IN.).
Jul 2, 6:53 PM MDT	HAIL 1	2 Wsw Brighton, CO	REPORT FROM MPING: QUARTER (1.00 IN.).
Jul 2, 6:55 PM MDT	HAIL 1.75	Brighton, CO

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.7 hours before the alert went out and 134 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: 382 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 2382 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 24 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

634 
WUUS55 KBOU 030042
SVRBOU
COC001-123-030115-
/O.NEW.KBOU.SV.W.0092.210703T0042Z-210703T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
642 PM MDT Fri Jul 2 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  South central Weld County in northeastern Colorado...
  Northwestern Adams County in northeastern Colorado...

* Until 715 PM MDT.

* At 642 PM MDT, a severe thunderstorm was located near Brighton, or 
  20 miles northeast of Denver, moving northeast at 5 mph. 
  Additional strong to severe storms are expected to develop 
  towards the southwest along I-76.  

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Thornton, northeastern Westminster, Commerce City, Northglenn,
  Brighton, northern Denver International Airport, Lochbuie, Hudson,
  Barr Lake and Todd Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4000 10446 3991 10466 3991 10469 3990 10471
      3990 10473 3987 10473 3981 10487 3981 10488
      3980 10489 3992 10503 3992 10501 3994 10501
      3995 10500 3996 10501 4012 10464
TIME...MOT...LOC 0042Z 244DEG 6KT 3998 10476 

HAIL...1.00IN
WIND...<50MPH
 
$$

SCHLATTER

2 follow-up statements

269 
WWUS55 KBOU 030055
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
655 PM MDT Fri Jul 2 2021

COC001-123-030115-
/O.CON.KBOU.SV.W.0092.000000T0000Z-210703T0115Z/
Weld CO-Adams CO-
655 PM MDT Fri Jul 2 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM MDT
FOR SOUTH CENTRAL WELD AND NORTHWESTERN ADAMS COUNTIES...

At 655 PM MDT, a severe thunderstorm was located 2 miles southwest 
of Brighton, or 18 miles northeast of Denver, moving east at 5 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
Thornton, northeastern Westminster, Commerce City, Northglenn,
Brighton, northern Denver International Airport, Lochbuie, Hudson,
Barr Lake and Todd Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4000 10446 3991 10466 3991 10469 3990 10471
      3990 10473 3987 10473 3981 10487 3981 10488
      3980 10489 3992 10503 3992 10501 3994 10501
      3995 10500 3996 10501 4012 10464
TIME...MOT...LOC 0055Z 250DEG 3KT 3997 10481 

HAIL...1.00IN
WIND...<50MPH
 
$$

SCHLATTER

768 
WWUS55 KBOU 030059
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
659 PM MDT Fri Jul 2 2021

COC001-123-030115-
/O.CON.KBOU.SV.W.0092.000000T0000Z-210703T0115Z/
Weld CO-Adams CO-
659 PM MDT Fri Jul 2 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM MDT
FOR SOUTH CENTRAL WELD AND NORTHWESTERN ADAMS COUNTIES...

At 658 PM MDT, a severe thunderstorm was located 2 miles west of 
Brighton Brighton, or 18 miles north of Denver, moving west at 5 
mph. Trained weather spotters reported reported golfball hail in 
Brighton in the last 5 minutes.

HAZARD...Golf ball size hail.

SOURCE...Trained weather spotters.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Thornton, northeastern Westminster, Commerce City, Northglenn,
Brighton, northern Denver International Airport, Lochbuie, Hudson,
Barr Lake and Todd Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4000 10446 3991 10466 3991 10469 3990 10471
      3990 10473 3987 10473 3981 10487 3981 10488
      3980 10489 3992 10503 3992 10501 3994 10501
      3995 10500 3996 10501 4012 10464
TIME...MOT...LOC 0058Z 079DEG 6KT 3997 10482 

HAIL...1.75IN
WIND...<50MPH
 
$$

SCHLATTER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 2, 6:36 PM MDT	Special Weather Statement	BOU	Denver	24 min
Jul 2, 7:11 PM MDT	Areal Flood Advisory	BOU	Adams	47 min
Jul 2, 7:13 PM MDT	Special Weather Statement	BOU	Denver	32 min
Jul 2, 7:17 PM MDT	Areal Flood Advisory	BOU	Larimer	88 min
Jul 3, 2:03 PM MDT	Areal Flood Advisory	BOU	Larimer	87 min
Jul 3, 2:22 PM MDT	Special Weather Statement	BOU	Weld	38 min
Jul 3, 3:11 PM MDT	Special Weather Statement	BOU	Weld	34 min
Jul 3, 3:23 PM MDT	Severe Thunderstorm Warning	BOU	Weld	37 min
Jul 3, 3:57 PM MDT	Severe Thunderstorm Warning	BOU	Morgan, Weld	33 min
Jul 3, 4:25 PM MDT	Special Weather Statement	BOU	Logan	20 min
Jul 3, 4:34 PM MDT	Special Weather Statement	BOU	Logan	26 min
Jul 3, 4:45 PM MDT	Special Weather Statement	BOU	Morgan	30 min
Jul 3, 4:53 PM MDT	Severe Thunderstorm Warning	BOU	Washington	37 min
Jul 3, 4:59 PM MDT	Severe Thunderstorm Warning	BOU	Logan	31 min
Jul 3, 5:05 PM MDT	Severe Thunderstorm Warning	BOU	Logan	25 min
Jul 3, 5:14 PM MDT	Special Weather Statement	BOU	Elbert	31 min
Jul 3, 5:20 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	25 min
Jul 3, 5:29 PM MDT	Severe Thunderstorm Warning	BOU	Washington	31 min
Jul 3, 5:38 PM MDT	Areal Flood Advisory	BOU	Logan	82 min
Jul 3, 5:40 PM MDT	Areal Flood Advisory	BOU	Elbert	95 min
Jul 3, 5:56 PM MDT	Severe Thunderstorm Warning	BOU	Washington	34 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.