Alert archive / Colorado / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 347, NWS Denver/Boulder, CO

July 28, 2023Clear Creek County, Gilpin County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 28, 2023, 3:29 PM MDT for Clear Creek County, Gilpin County, Jefferson County, Colorado. It was in force for 31 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 28, 2023, 3:29 PM MDT (21:29 UTC)
Expired: Jul 28, 2023, 4:00 PM MDT
In force: 31 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Clear Creek County, CO, Gilpin County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 80 km from the middle of the area, began a volume at 21:32 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, 9.5 hours before the alert went out and 268 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: 20 J/kg
Mixed-layer CIN: -310 J/kg
Mixed-layer LCL: 3187 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 119 m²/s²
0-3 km storm-relative helicity: 141 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 28, 2:49 PM MDT, 40 minutes earlier.

Area forecast discussion, Jul 28, 2:49 PM MDT, 40 minutes before

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Hazardous weather outlook, Jul 28, 10:15 AM MDT, 5 hours 14 minutes before

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In the hours before

Special weather statement, Jul 28, 1:59 PM MDT, 1 hour 30 minutes before

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Special weather statement, Jul 28, 2:36 PM MDT, 53 minutes before

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Special weather statement, Jul 28, 3:19 PM MDT, 10 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 6:31 PM MDT	Areal Flood Advisory	BOU	Larimer	3 hr
Jul 27, 6:45 PM MDT	Special Weather Statement	BOU	Weld	45 min
Jul 27, 9:35 PM MDT	Special Weather Statement	BOU	Grand	40 min
Jul 28, 1:59 PM MDT	Special Weather Statement	BOU	Denver	31 min
Jul 28, 2:36 PM MDT	Special Weather Statement	BOU	Arapahoe, Broomfield, Denver	39 min
Jul 28, 2:41 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	34 min
Jul 28, 2:50 PM MDT	Severe Thunderstorm Warning	BOU	Weld	25 min
Jul 28, 3:11 PM MDT	Severe Thunderstorm Warning	BOU	Weld	49 min
Jul 28, 3:19 PM MDT	Special Weather Statement	BOU	Gilpin	26 min
Jul 28, 3:59 PM MDT	Severe Thunderstorm Warning	BOU	Boulder	31 min
Jul 28, 4:20 PM MDT	Special Weather Statement	BOU	Arapahoe	40 min
Jul 28, 5:24 PM MDT	Special Weather Statement	BOU	Weld	51 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2023 Every severe thunderstorm warning in 2023

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.