Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 103, NWS Denver/Boulder, CO

July 9, 2021Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 9, 2021, 3:25 PM MDT for Weld County, Colorado. It was in force for 38 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 9, 2021, 3:25 PM MDT (21:25 UTC)
Expired
Jul 9, 2021, 4:03 PM MDT
In force
38 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), 94 km from the middle of the area, began a volume at 21:28 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 9, 2:16 PM MDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 9.4 hours before the alert went out and 106 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 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 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 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.193958Sfc1 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
5 J/kg
Mixed-layer CIN
-346 J/kg
Mixed-layer LCL
3383 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

734 
WUUS55 KBOU 092125
SVRBOU
COC123-092215-
/O.NEW.KBOU.SV.W.0103.210709T2125Z-210709T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
325 PM MDT Fri Jul 9 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Northeastern Weld County in northeastern Colorado...

* Until 415 PM MDT.

* At 325 PM MDT, a severe thunderstorm was located near Pawnee
  Buttes, or 35 miles southwest of Kimball, moving southeast at 30
  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.

* Locations impacted include...
  Stoneham, New Raymer and Pawnee Buttes. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Heavy rainfall is occurring with this storm, and may lead to flash 
flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4061 10405 4077 10408 4084 10401 4082 10375
      4077 10358 4053 10358 4053 10394
TIME...MOT...LOC 2125Z 300DEG 27KT 4078 10399 

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

RJK
3 follow-up statements
050 
WWUS55 KBOU 092138
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
338 PM MDT Fri Jul 9 2021

COC123-092215-
/O.CON.KBOU.SV.W.0103.000000T0000Z-210709T2215Z/
Weld CO-
338 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MDT
FOR EAST CENTRAL WELD COUNTY...

At 338 PM MDT, a severe thunderstorm was located 8 miles southeast of
Pawnee Buttes, or 33 miles north of Fort Morgan, moving southeast at
30 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.

Locations impacted include...
Stoneham and New Raymer. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Heavy rainfall is occurring with this storm, and may lead to flash 
flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4062 10388 4074 10394 4080 10386 4080 10373
      4077 10358 4053 10358 4053 10382
TIME...MOT...LOC 2138Z 300DEG 27KT 4073 10388 

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

RJK
367 
WWUS55 KBOU 092153
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
353 PM MDT Fri Jul 9 2021

COC123-092215-
/O.CON.KBOU.SV.W.0103.000000T0000Z-210709T2215Z/
Weld CO-
353 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MDT
FOR EASTERN WELD COUNTY...

At 353 PM MDT, a severe thunderstorm was located 5 miles northwest of
Stoneham, or 28 miles north of Fort Morgan, moving southeast at 30
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.

Locations impacted include...
Stoneham.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Heavy rainfall is occurring with this storm, and may lead to flash 
flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4065 10383 4073 10380 4074 10358 4053 10358
      4053 10379
TIME...MOT...LOC 2153Z 303DEG 28KT 4067 10375 

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

RJK
508 
WWUS55 KBOU 092203
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
403 PM MDT Fri Jul 9 2021

COC123-092213-
/O.CAN.KBOU.SV.W.0103.000000T0000Z-210709T2215Z/
Weld CO-
403 PM MDT Fri Jul 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN WELD COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
northeastern Colorado.

LAT...LON 4065 10383 4073 10380 4074 10358 4053 10358
      4053 10379
TIME...MOT...LOC 2202Z 300DEG 27KT 4063 10366 

$$

RJK

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 8, 6:02 PM MDTSpecial Weather StatementBOUPhillips43 min
Jul 9, 2:34 PM MDTSevere Thunderstorm WarningBOUWeld41 min
Jul 9, 3:00 PM MDTAreal Flood AdvisoryBOUGrand2 hr
Jul 9, 3:58 PM MDTSevere Thunderstorm WarningBOULogan47 min
Jul 9, 4:44 PM MDTSevere Thunderstorm WarningBOULogan36 min
Jul 9, 5:22 PM MDTSpecial Weather StatementBOUPhillips38 min
Jul 9, 5:40 PM MDTSpecial Weather StatementBOUMorgan35 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.