Alert archive / Wyoming / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 404, NWS Cheyenne, WY

September 22, 2023Goshen County, Platte County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 22, 2023, 7:46 PM MDT for Goshen County, Platte County, Wyoming. It was in force for 44 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, 7:46 PM MDT (01:46 UTC)
Expired: Sep 22, 2023, 8:30 PM MDT
In force: 44 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Goshen County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 107 km from the middle of the area, began a volume at 01:47 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, 1.8 hours before the alert went out and 355 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, 1 hour 2 minutes earlier.

Area forecast discussion, Sep 22, 6:44 PM MDT, 1 hour 2 minutes before

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In the hours before

Special weather statement, Sep 22, 4:00 PM MDT, 3 hours 46 minutes before

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Local storm report, Sep 22, 4:12 PM MDT, 3 hours 34 minutes before

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Local storm report, Sep 22, 5:17 PM MDT, 2 hours 29 minutes before

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Local storm report, Sep 22, 5:48 PM MDT, 1 hour 58 minutes before

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Special weather statement, Sep 22, 7:25 PM MDT, 21 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
725 PM MDT Fri Sep 22 2023

WYZ101-102-230200-
Converse County Lower Elevations WY-Niobrara County WY-
725 PM MDT Fri Sep 22 2023

...A strong thunderstorm will impact portions of southwestern
Niobrara and southeastern Converse Counties through 800 PM MDT...

At 725 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Keeline, or 22 miles west of Lusk, moving northeast at
20 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Manville, Keeline and Lost Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Cheyenne.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
east central Wyoming.

&&

LAT...LON 4265 10506 4278 10507 4302 10475 4277 10452
TIME...MOT...LOC 0125Z 242DEG 14KT 4276 10491

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Wills

Local storm report, Sep 22, 7:33 PM MDT, 13 minutes before

Preliminary Local Storm Report
National Weather Service Cheyenne WY
733 PM MDT Fri Sep 22 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0727 PM     Hail             Lost Springs            42.77N 104.92W
09/22/2023  M1.00 inch       Converse           WY   Trained Spotter

            Trained spotter reports nickel to some
            quarter sized hail.

&&

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 22, 7:18 PM MDT	Severe Thunderstorm Warning	CYS	Niobrara, Platte	27 min
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, 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.