Alert archive / Wyoming / Winter Storm Warnings in 2017

Winter Storm Warning 19, NWS Riverton, WY

October 31, 20177 counties in Wyoming

NWS Riverton, WY issued this winter storm warning at Oct 31, 2017, 3:00 PM MDT for 7 counties in Wyoming. It took effect at Nov 1, 2017, 6:00 AM MDT. It was in force for 31 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Oct 31, 2017, 3:00 PM MDT (21:00 UTC)
In effect from: Nov 1, 2017, 6:00 AM MDT
Expired: Nov 2, 2017, 1:24 PM MDT
In force: 31 hr
Issued by: NWS Riverton, WY

Counties Big Horn County, WY, Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Park County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 93 km from the middle of the area, began a volume at 21:05 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

Riverton, WY (KRIW), launched 12:00Z, 9.0 hours before the alert went out and 90 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1454 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 92 m²/s²
0-3 km storm-relative helicity: 198 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 winter storm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Riverton, WY wrote its last area forecast discussion before this winter storm warning went out at Oct 31, 2:38 PM MDT, 22 minutes earlier.

Area forecast discussion, Oct 31, 2:38 PM MDT, 22 minutes before

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Hazardous weather outlook, Oct 31, 2:43 PM MDT, 17 minutes before

Hazardous Weather Outlook
National Weather Service Riverton WY
243 PM MDT Tue Oct 31 2017

WYZ001>020-022>030-012045-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
243 PM MDT Tue Oct 31 2017

...HIGH WIND WARNING TONIGHT THROUGH WEDNESDAY FOR PORTIONS OF
NORTHERN AND CENTRAL WYOMING ALONG AND EAST OF THE DIVIDE AND ALSO
FOR EASTERN SWEETWATER COUNTY...

...WINTER STORM WARNING FOR THE ABSAROKA AND BIGHORN MOUNTAINS
WEDNESDAY THROUGH THURSDAY...

...WINTER STORM WATCH FOR THE CODY FOOTHILLS AND JOHNSON COUNTY
WEDNESDAY NIGHT THROUGH THURSDAY...

This Hazardous Weather Outlook is for Western and Central
Wyoming.

.DAY ONE...Tonight.

Becoming very windy tonight along the east slope of the Continental
Divide as well as along the adjacent foothills from Cody to Dubois
to Lander.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wednesday through Thursday...Becoming very windy along the southern
wind corridor from Rock Springs to Casper as well as other
portions of Central Wyoming. Heavy snow possible in the northern
mountains Wednesday through Thursday and in the Cody Foothills and
Northern Johnson County Wednesday night and Thursday.

Friday through Saturday...Significant mountain snowfall possible
in the northwest mountains. Strong winds from Rock Springs to
Casper much of this period. Strong winds in the mountains and east
slope of most mountain ranges on Saturday.

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
wind speeds greater than 50 mph. Thank you.

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 31, 2:27 AM MDT	Winter Storm Watch	RIW	Big Horn, Fremont, Hot Springs, Johnson, Natrona, Park and 1 more	25 hr
Oct 31, 8:46 AM MDT	High Wind Warning	RIW	Fremont, Hot Springs, Natrona, Park, Sublette, Sweetwater	34 hr

Nearby

Winter Storm Warnings in Wyoming, 2017 Every winter storm warning in 2017

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.