Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 67, NWS Denver/Boulder, CO

June 13, 2021Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 13, 2021, 5:54 PM MDT for Weld County, Colorado. It was in force for 51 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 13, 2021, 5:54 PM MDT (23:54 UTC)
Expired
Jun 13, 2021, 6:45 PM MDT
In force
51 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 47 km from the middle of the area, began a volume at 23:54 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, 11.9 hours before the alert went out and 149 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-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2021-06-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 827 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-06-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
827 J/kg
Mixed-layer CIN
-387 J/kg
Mixed-layer LCL
1858 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
10 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

313 
WUUS55 KBOU 132354
SVRBOU
COC123-140045-
/O.NEW.KBOU.SV.W.0067.210613T2354Z-210614T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
554 PM MDT Sun Jun 13 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  North central Weld County in northeastern Colorado...

* Until 645 PM MDT.

* At 554 PM MDT, a severe thunderstorm was located 11 miles west of
  Hereford, or 21 miles southeast of Cheyenne, moving east at 10 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Hereford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4077 10428 4077 10462 4100 10461 4100 10423
TIME...MOT...LOC 2354Z 270DEG 7KT 4092 10451 

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

SCHLATTER
2 follow-up statements
267 
WWUS55 KBOU 140004
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
604 PM MDT Sun Jun 13 2021

COC123-140045-
/O.CON.KBOU.SV.W.0067.000000T0000Z-210614T0045Z/
Weld CO-
604 PM MDT Sun Jun 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT
FOR NORTH CENTRAL WELD COUNTY...

At 604 PM MDT, a severe thunderstorm was located 10 miles west of
Hereford, or 21 miles southeast of Cheyenne, moving east at 5 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Hereford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4077 10428 4077 10462 4100 10461 4100 10423
TIME...MOT...LOC 0004Z 272DEG 6KT 4092 10450 

HAIL...1.50IN
WIND...<50MPH
 
$$

SCHLATTER
147 
WWUS55 KBOU 140027
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
627 PM MDT Sun Jun 13 2021

COC123-140045-
/O.CON.KBOU.SV.W.0067.000000T0000Z-210614T0045Z/
Weld CO-
627 PM MDT Sun Jun 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT
FOR NORTH CENTRAL WELD COUNTY...

At 627 PM MDT, a severe thunderstorm was located 13 miles southwest
of Hereford, or 24 miles southeast of Cheyenne, moving southeast at 5
mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Hereford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4077 10428 4077 10462 4100 10461 4100 10423
TIME...MOT...LOC 0027Z 326DEG 4KT 4086 10453 

HAIL...1.75IN
WIND...60MPH
 
$$

SCHLATTER

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 13, 4:02 PM MDTSpecial Weather StatementBOUDouglas43 min
Jun 13, 4:27 PM MDTSpecial Weather StatementBOUDenver33 min
Jun 13, 4:38 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver37 min
Jun 13, 4:59 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver31 min
Jun 13, 5:14 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver31 min
Jun 13, 5:45 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver, Douglas31 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.