Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 109, NWS Denver/Boulder, CO

July 15, 2021Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 15, 2021, 5:01 PM MDT for Weld County, Colorado. It was in force for 44 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 15, 2021, 5:01 PM MDT (23:01 UTC)
Expired: Jul 15, 2021, 5:45 PM MDT
In force: 44 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 29 km from the middle of the area, began a volume at 23:04 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, 11.0 hours before the alert went out and 167 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: 6 J/kg
Mixed-layer CIN: -427 J/kg
Mixed-layer LCL: 1726 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 45 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

848 
WUUS55 KBOU 152301
SVRBOU
COC123-152345-
/O.NEW.KBOU.SV.W.0109.210715T2301Z-210715T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
501 PM MDT Thu Jul 15 2021

The National Weather Service in Denver Colorado has issued a

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

* Until 545 PM MDT.

* At 501 PM MDT, a severe thunderstorm was located 11 miles northeast
  of Rockport, or 14 miles southeast of Cheyenne, moving south 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.

* This severe thunderstorm will remain over mainly rural areas of
  north central Weld County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4100 10469 4100 10449 4087 10445 4086 10469
TIME...MOT...LOC 2301Z 348DEG 11KT 4099 10461 

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

ENTREKIN

1 follow-up statement

556 
WWUS55 KBOU 152325
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
525 PM MDT Thu Jul 15 2021

COC123-152345-
/O.CON.KBOU.SV.W.0109.000000T0000Z-210715T2345Z/
Weld CO-
525 PM MDT Thu Jul 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM MDT
FOR NORTH CENTRAL WELD COUNTY...

At 525 PM MDT, a severe thunderstorm was located 11 miles east of
Rockport, or 18 miles southeast of Cheyenne, moving south at 10 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.

This severe thunderstorm will remain over mainly rural areas of north
central Weld County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4100 10467 4100 10453 4087 10445 4086 10469
TIME...MOT...LOC 2325Z 340DEG 10KT 4094 10458 

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

ENTREKIN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 6:06 PM MDT	Special Weather Statement	BOU	Weld	24 min
Jul 14, 6:29 PM MDT	Special Weather Statement	BOU	Morgan	31 min
Jul 14, 6:47 PM MDT	Areal Flood Advisory	BOU	Denver	88 min
Jul 14, 7:39 PM MDT	Areal Flood Advisory	BOU	Morgan	72 min
Jul 15, 1:37 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	38 min
Jul 15, 2:42 PM MDT	Special Weather Statement	BOU	Lincoln	48 min
Jul 15, 2:59 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	46 min
Jul 15, 3:19 PM MDT	Special Weather Statement	BOU	Washington	26 min
Jul 15, 3:38 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	52 min
Jul 15, 5:44 PM MDT	Severe Thunderstorm Warning	BOU	Weld	29 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.