Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 9, NWS Grand Junction, CO

July 28, 2021Mesa County, Colorado

NWS Grand Junction, CO issued this severe thunderstorm warning at Jul 28, 2021, 5:31 PM MDT for Mesa County, Colorado. It was in force for 29 min. 1 report 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 28, 2021, 5:31 PM MDT (23:31 UTC)
Expired: Jul 28, 2021, 6:00 PM MDT
In force: 29 min
Issued by: NWS Grand Junction, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Mesa County, CO

The radar

The Grand Junction radar (KGJX), 21 km from the middle of the area, began a volume at 23:33 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 28, 5:42 PM MDT	HAIL 1	3 Ese Skyway, CO	HAIL ACCUMULATING ESTIMATED 6 INCHES DEEP NEAR SKYWAY ON THE GRAND MESA.

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

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 11.5 hours before the alert went out and 46 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: 68 J/kg
Mixed-layer CIN: -138 J/kg
Mixed-layer LCL: 1671 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -38 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

958 
WUUS55 KGJT 282331
SVRGJT
COC077-290000-
/O.NEW.KGJT.SV.W.0009.210728T2331Z-210729T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Junction CO
531 PM MDT Wed Jul 28 2021

The National Weather Service in Grand Junction has issued a

* Severe Thunderstorm Warning for...
  North central Mesa County in west central Colorado...

* Until 600 PM MDT.

* At 531 PM MDT, a severe thunderstorm was located 9 miles south of
  Collbran, or 34 miles east of Grand Junction, moving west at 20
  mph. This storm was near Crag Crest in Grand Mesa National Forest. 

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

  SOURCE...Radar indicated.

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

* This severe thunderstorm will remain over mainly rural areas of
  north central Mesa County, including the following locations...
  Skyway, Mesa, Plateau City and Molina.

This includes Colorado 65 between mile markers 31 and 54.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3907 10784 3908 10786 3906 10791 3906 10797
      3903 10803 3902 10804 3898 10818 3912 10825
      3926 10815 3915 10781 3908 10781
TIME...MOT...LOC 2331Z 093DEG 17KT 3911 10793 

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

Charnick

1 follow-up statement

606 
WWUS55 KGJT 282354
SVSGJT

Severe Weather Statement
National Weather Service Grand Junction CO
554 PM MDT Wed Jul 28 2021

COC077-290000-
/O.CON.KGJT.SV.W.0009.000000T0000Z-210729T0000Z/
Mesa CO-
554 PM MDT Wed Jul 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM MDT
FOR NORTH CENTRAL MESA COUNTY...

At 554 PM MDT, a severe thunderstorm was located 10 miles southwest
of Collbran, or 26 miles east of Grand Junction, moving west at 20
mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Mesa, Skyway, Plateau City and Molina. 

 This includes Colorado 65 between mile markers 31 and 54.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3903 10803 3902 10804 3898 10818 3912 10825
      3926 10815 3919 10793 3906 10793 3906 10797
TIME...MOT...LOC 2354Z 093DEG 17KT 3912 10807 

HAIL...1.00IN
WIND...70MPH
 
$$

Charnick

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 27, 6:16 PM MDT	Special Weather Statement	GJT	La Plata	29 min
Jul 27, 7:28 PM MDT	Areal Flood Advisory	GJT	La Plata	3 hr
Jul 27, 8:58 PM MDT	Special Weather Statement	GJT	Montezuma	47 min
Jul 28, 1:54 PM MDT	Areal Flood Advisory	GJT	Dolores, Montezuma	3 hr
Jul 28, 2:08 PM MDT	Flash Flood Watch	GJT	Eagle, Garfield, Moffat, Pitkin, Rio Blanco, Routt	8 hr
Jul 28, 2:14 PM MDT	Flash Flood Warning	GJT	San Miguel	3 hr
Jul 28, 2:28 PM MDT	Flash Flood Watch	GJT	Archuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more	34 hr
Jul 28, 2:28 PM MDT	Flash Flood Watch	GJT	Archuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more	58 hr
Jul 28, 2:35 PM MDT	Areal Flood Advisory	GJT	Rio Blanco	3 hr
Jul 28, 3:08 PM MDT	Areal Flood Advisory	GJT	Rio Blanco	3 hr
Jul 28, 3:14 PM MDT	Special Weather Statement	GJT	Rio Blanco	46 min
Jul 28, 3:19 PM MDT	Flash Flood Warning	GJT	San Miguel	3 hr
Jul 28, 3:40 PM MDT	Special Weather Statement	GJT	Ouray	50 min
Jul 28, 3:47 PM MDT	Flash Flood Warning	GJT	Rio Blanco	2 hr
Jul 28, 3:56 PM MDT	Special Weather Statement	GJT	Archuleta	49 min
Jul 28, 4:04 PM MDT	Special Weather Statement	GJT	La Plata	26 min
Jul 28, 4:08 PM MDT	Special Weather Statement	GJT	Montrose	22 min
Jul 28, 4:28 PM MDT	Special Weather Statement	GJT	Garfield	32 min
Jul 28, 4:47 PM MDT	Areal Flood Advisory	GJT	Mesa	3 hr
Jul 28, 5:07 PM MDT	Special Weather Statement	GJT		23 min
Jul 28, 5:22 PM MDT	Flash Flood Warning	GJT	Mesa, Montrose	77 min
Jul 28, 5:25 PM MDT	Severe Thunderstorm Warning	GJT	Mesa, Montrose	35 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.