Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 13, NWS Grand Junction, CO

July 29, 2021Montrose County, San Miguel County, Colorado

NWS Grand Junction, CO issued this severe thunderstorm warning at Jul 29, 2021, 3:18 PM MDT for Montrose County, San Miguel County, Colorado. It was in force for 27 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 29, 2021, 3:18 PM MDT (21:18 UTC)
Expired
Jul 29, 2021, 3:45 PM MDT
In force
27 min
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Montrose County, CO, San Miguel County, CO

The radar

The Grand Junction radar (KGJX), 113 km from the middle of the area, began a volume at 21:18 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

Grand Junction, CO (KGJT), launched 12:00Z, 9.3 hours before the alert went out and 121 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, Grand Junction, CO at 12:00Z on 2021-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 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, Grand Junction, CO at 12:00Z on 2021-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
12 J/kg
Mixed-layer CIN
-398 J/kg
Mixed-layer LCL
1614 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

852 
WUUS55 KGJT 292118
SVRGJT
COC085-113-292145-
/O.NEW.KGJT.SV.W.0013.210729T2118Z-210729T2145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Junction CO
318 PM MDT Thu Jul 29 2021

The National Weather Service in Grand Junction has issued a

* Severe Thunderstorm Warning for...
  North central San Miguel County in southwestern Colorado...
  Southern Montrose County in west central Colorado...

* Until 345 PM MDT.

* At 317 PM MDT, a severe thunderstorm was located near Norwood, or
  38 miles southwest of Montrose, moving north at 15 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Norwood.

This includes the following highways...
 Colorado 141 between mile markers 50 and 51.
 Colorado 145 between mile markers 101 and 108.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3800 10826 3799 10830 3799 10837 3815 10852
      3818 10828
TIME...MOT...LOC 2117Z 171DEG 13KT 3803 10831 

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

ERW
2 follow-up statements
067 
WWUS55 KGJT 292127
SVSGJT

Severe Weather Statement
National Weather Service Grand Junction CO
327 PM MDT Thu Jul 29 2021

COC085-113-292145-
/O.CON.KGJT.SV.W.0013.000000T0000Z-210729T2145Z/
San Miguel CO-Montrose CO-
327 PM MDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM MDT
FOR NORTH CENTRAL SAN MIGUEL AND SOUTHERN MONTROSE COUNTIES...

At 326 PM MDT, a severe thunderstorm was located near Norwood, 
moving north at 15 mph.

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.

Locations impacted include...
Norwood.

 This includes the following highways...
 Colorado 141 between mile markers 50 and 51.
 Colorado 145 between mile markers 101 and 108.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3803 10827 3804 10837 3815 10852 3818 10828
TIME...MOT...LOC 2126Z 171DEG 13KT 3806 10832 

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

15
966 
WWUS55 KGJT 292142
SVSGJT

Severe Weather Statement
National Weather Service Grand Junction CO
342 PM MDT Thu Jul 29 2021

COC085-113-292150-
/O.EXP.KGJT.SV.W.0013.000000T0000Z-210729T2145Z/
San Miguel CO-Montrose CO-
342 PM MDT Thu Jul 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SAN MIGUEL AND
SOUTHERN MONTROSE COUNTIES WILL EXPIRE AT 345 PM MDT...
                
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 will be allowed to expire.

LAT...LON 3803 10827 3804 10837 3815 10852 3818 10828
TIME...MOT...LOC 2140Z 171DEG 13KT 3810 10833 

$$

ERW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 6:00 PM MDTSevere Thunderstorm WarningGJTDelta, Mesa30 min
Jul 28, 6:30 PM MDTSevere Thunderstorm WarningGJTGarfield, Mesa60 min
Jul 28, 6:32 PM MDTFlash Flood WarningGJTMesa54 min
Jul 28, 7:21 PM MDTFlash Flood Warning Considerable damage threatGJTGarfield, Mesa46 min
Jul 28, 7:31 PM MDTAreal Flood AdvisoryGJTMesa119 min
Jul 28, 7:32 PM MDTSpecial Weather StatementGJTMesa43 min
Jul 29, 1:43 PM MDTSpecial Weather StatementGJTMesa47 min
Jul 29, 2:02 PM MDTSpecial Weather StatementGJTSan Miguel43 min
Jul 29, 2:04 PM MDTSpecial Weather StatementGJTDolores41 min
Jul 29, 2:36 PM MDTAreal Flood AdvisoryGJTDolores, San Miguel3 hr
Jul 29, 2:53 PM MDTAreal Flood AdvisoryGJTArchuleta112 min
Jul 29, 3:07 PM MDTSevere Thunderstorm WarningGJTMontezuma23 min
Jul 29, 3:28 PM MDTSevere Thunderstorm WarningGJTMontezuma32 min
Jul 29, 3:33 PM MDTSpecial Weather StatementGJTOuray42 min
Jul 29, 3:47 PM MDTFlash Flood WarningGJTSan Miguel3 hr
Jul 29, 3:52 PM MDTSevere Thunderstorm WarningGJTMontezuma23 min
Jul 29, 4:11 PM MDTFlash Flood WarningGJTPitkin4 hr
Jul 29, 4:12 PM MDTFlash Flood Warning Considerable damage threatGJTEagle, Garfield66 min
Jul 29, 4:43 PM MDTFlash Flood WarningGJTMontezuma3 hr
Jul 29, 4:54 PM MDTSpecial Weather StatementGJTDelta51 min
Jul 29, 4:54 PM MDTSpecial Weather StatementGJTMontezuma51 min
Jul 29, 4:58 PM MDTAreal Flood AdvisoryGJTMontezuma3 hr
Jul 29, 5:10 PM MDTSpecial Weather StatementGJTGarfield50 min
Jul 29, 5:11 PM MDTSpecial Weather StatementGJTDolores49 min
Jul 29, 5:14 PM MDTSpecial Weather StatementGJT46 min
Jul 29, 5:29 PM MDTSpecial Weather StatementGJTMontezuma46 min
Jul 29, 5:34 PM MDTAreal Flood AdvisoryGJTMontezuma3 hr
Jul 29, 5:44 PM MDTSpecial Weather StatementGJTGarfield46 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.