Alert archive / Wyoming / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 402, NWS Cheyenne, WY

September 22, 2023Niobrara County, Platte County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 22, 2023, 7:18 PM MDT for Niobrara County, Platte County, Wyoming. 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 counties it named.

The facts

Issued: Sep 22, 2023, 7:18 PM MDT (01:18 UTC)
Expired: Sep 22, 2023, 7:45 PM MDT
In force: 27 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Niobrara County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 161 km from the middle of the area, began a volume at 01:19 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.

Issued	Product	Office	Lasted
Sep 22, 1:36 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 1.3 hours before the alert went out and 378 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: 173 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 882 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

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 Cheyenne, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 22, 6:44 PM MDT, 34 minutes earlier.

Area forecast discussion, Sep 22, 6:44 PM MDT, 34 minutes before

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In the hours before

Local storm report, Sep 22, 3:54 PM MDT, 3 hours 24 minutes before

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Local storm report, Sep 22, 3:58 PM MDT, 3 hours 20 minutes before

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Special weather statement, Sep 22, 4:00 PM MDT, 3 hours 18 minutes before

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Local storm report, Sep 22, 4:12 PM MDT, 3 hours 6 minutes before

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Local storm report, Sep 22, 5:17 PM MDT, 2 hours 1 minute before

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Local storm report, Sep 22, 5:48 PM MDT, 1 hour 30 minutes before

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The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 22, 7:25 PM MDT	Special Weather Statement	CYS	Niobrara	35 min
Sep 22, 7:35 PM MDT	Severe Thunderstorm Warning	CYS	Niobrara	24 min
Sep 22, 7:46 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Platte	44 min
Sep 22, 8:31 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Platte	44 min
Sep 22, 9:14 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	35 min
Sep 22, 9:16 PM MDT	Special Weather Statement	CYS	Niobrara	29 min
Sep 22, 9:40 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Platte	50 min
Sep 22, 10:32 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	43 min
Sep 23, 1:26 PM MDT	Frost Advisory	CYS	Albany, Carbon	19 hr
Sep 23, 1:26 PM MDT	Freeze Warning	CYS	Albany, Carbon	19 hr
Sep 22, 10:36 PM MDT	Severe Thunderstorm Warning	CYS	Dawes, Sioux	54 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 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.