Alert archive / Wyoming / Winter Storm Warnings in 2018

Winter Storm Warning 8, NWS Riverton, WY

April 1, 20187 counties in Wyoming

NWS Riverton, WY issued this winter storm warning at Apr 1, 2018, 12:51 PM MDT for 7 counties in Wyoming. It took effect at Apr 1, 2018, 6:00 PM MDT. It was in force for 34 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
Apr 1, 2018, 12:51 PM MDT (18:51 UTC)
In effect from
Apr 1, 2018, 6:00 PM MDT
Expired
Apr 3, 2018, 3:47 AM MDT
In force
34 hr
Issued by
NWS Riverton, WY

Counties Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Lincoln County, WY, Park County, WY, Sublette County, WY, Teton County, WY

The radar

The Riverton/Lander radar (KRIW), 74 km from the middle of the area, began a volume at 18:57 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, 6.9 hours before the alert went out and 79 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, Riverton, WY at 12:00Z on 2018-04-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2018-04-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
687 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
274 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 Apr 1, 10:55 AM MDT, 1 hour 56 minutes earlier.

Area forecast discussion, Apr 1, 10:55 AM MDT, 1 hour 56 minutes before
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Hazardous weather outlook, Apr 1, 3:12 AM MDT, 9 hours 39 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
312 AM MDT Sun Apr 1 2018

WYZ001>020-022>030-021100-
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-
312 AM MDT Sun Apr 1 2018

...Winter Storm Watches in Effect for the Northern Mountains
Tonight through Monday Evening...

...High Wind Watches in Effect for Portions of South and Central
Wyoming Late Tonight through Monday Evening...

This Hazardous Weather Outlook is for Western and Central
Wyoming.

.DAY ONE...Today and Tonight.

Valley rain or a rain/snow mix and mountain snow will increase
across western Wyoming tonight. Strong winds with gusts over 60
mph may develop down the east slopes of the Wind River Mountains
into the Lander Foothills and South Pass area late tonight.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Monday and Monday night...A strong cold front will push across the
area Monday. Snow, heavy at times, along with blowing and drifting
snow is expected to impact much of western Wyoming Monday morning
into the afternoon. Please see Winter Storm Watches for more
information. High winds are possible across portions of central
and southern Wyoming, including the Interstate 80 corridor,
through Monday evening. Please see High Wind Watches for the
latest information.

.SPOTTER INFORMATION STATEMENT...

Please report snow amounts,wind gusts over 50 mph, or any wind
damage. Thank you.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 1, 3:34 AM MDTWinter Storm WatchRIWBig Horn, Fremont, Hot Springs, Johnson, Lincoln, Natrona and 4 more23 hr
Apr 1, 3:51 AM MDTHigh Wind WatchRIWBig Horn, Fremont, Johnson, Lincoln, Natrona, Park and 2 more22 hr
Apr 1, 12:48 PM MDTHigh Wind WarningRIWBig Horn, Fremont, Johnson, Lincoln, Natrona, Park and 2 more31 hr

Nearby

Winter Storm Warnings in Wyoming, 2018Every winter storm warning 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.