Alert archive / Wyoming / Special Weather Statements in 2018

Special Weather Statement, NWS Cheyenne, WY

June 21, 2018Converse County, Wyoming

NWS Cheyenne, WY issued this special weather statement at Jun 21, 2018, 7:21 PM MDT for Converse County, Wyoming. It was in force for 39 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
Jun 21, 2018, 7:21 PM MDT (01:21 UTC)
Expired
Jun 21, 2018, 8:00 PM MDT
In force
39 min
Issued by
NWS Cheyenne, WY

County Converse County, WY

The radar

The Cheyenne radar (KCYS), 193 km from the middle of the area, began a volume at 01:24 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

Rapid City, SD (KRAP), launched 00:00Z, 1.4 hours before the alert went out and 236 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, Rapid City, SD at 00:00Z on 2018-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 7 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, Rapid City, SD at 00:00Z on 2018-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
7 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
1611 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
245 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

950 
WWUS85 KCYS 220121
SPSCYS

Special Weather Statement
National Weather Service Cheyenne WY
721 PM MDT THU JUN 21 2018
 
WYZ101-102-220200-
Converse County Lower Elevations WY-Niobrara County WY-
721 PM MDT THU JUN 21 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NIOBRARA AND EAST
CENTRAL CONVERSE COUNTIES UNTIL 800 PM MDT...

At 720 PM MDT, Doppler radar was tracking a strong thunderstorm near
Douglas, moving east at 35 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Douglas.

This includes Interstate 25 in Wyoming between mile markers 140 and
144.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4275 10548 4291 10554 4305 10501 4280 10489
TIME...MOT...LOC 0120Z 259DEG 31KT 4286 10540 

$$

Claycomb

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 21, 6:22 PM MDTSevere Thunderstorm WarningCYSLaramie38 min
Jun 21, 6:49 PM MDTSpecial Weather StatementCYSLaramie11 min
Jun 21, 6:56 PM MDTSevere Thunderstorm WarningCYSLaramie14 min
Jun 21, 7:03 PM MDTSevere Thunderstorm WarningCYSConverse29 min
Jun 22, 5:19 PM MDTSpecial Weather StatementCYSGoshen26 min
Jun 22, 5:30 PM MDTSpecial Weather StatementCYSGoshen30 min
Jun 22, 5:45 PM MDTSevere Thunderstorm WarningCYSGoshen45 min
Jun 21, 11:41 PM MDTSpecial Weather StatementCYSScotts Bluff34 min
Jun 22, 2:22 PM MDTSpecial Weather StatementCYSCheyenne38 min
Jun 22, 2:33 PM MDTSevere Thunderstorm WarningCYSCheyenne16 min
Jun 22, 3:51 PM MDTSpecial Weather StatementCYSCheyenne24 min

Nearby

Special Weather Statements in Wyoming, 2018Every special weather statement in 2018

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.