Alert archive / Wyoming / Winter Storm Warnings in 2020

Winter Storm Warning 9, NWS Riverton, WY

September 7, 20209 counties in Wyoming

NWS Riverton, WY issued this winter storm warning at Sep 7, 2020, 4:34 AM MDT for 9 counties in Wyoming. It took effect at Sep 7, 2020, 12:00 PM MDT. It was in force for 30 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
Sep 7, 2020, 4:34 AM MDT (10:34 UTC)
In effect from
Sep 7, 2020, 12:00 PM MDT
Expired
Sep 8, 2020, 6:00 PM MDT
In force
30 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, Sublette County, WY, Sweetwater County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 47 km from the middle of the area, began a volume at 10:35 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.

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 Sep 6, 10:41 PM MDT, 5 hours 53 minutes earlier.

Area forecast discussion, Sep 6, 10:41 PM MDT, 5 hours 53 minutes before
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Hazardous weather outlook, Sep 7, 4:29 AM MDT, 5 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
429 AM MDT Mon Sep 7 2020

WYZ001>020-022>030-081030-
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-
429 AM MDT Mon Sep 7 2020

...Red Flag Warning continues through this evening across
southern Wyoming...

...Multiple Winter Storm Warnings and Advisories Across the Area
this Afternoon through Tuesday, see individual products for
details...

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight.

Critical fire weather conditions across southern portions. Please
see the red flag warning product for more details.

A strong cold front will push across the Cowboy State.
Significant precipitation is expected with this system east of the
Divide, especially overnight tonight. Significant snow possible
in the mountains east of the Divide as well as central Wyoming.
Please see the winter weather statements for more details.
Widespread freezes are expected tonight and Tuesday night.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday...Winter weather will continue for portions of central and
southern Wyoming.

Strong to high northeast winds are expected across southern
Wyoming, especially along the I-80 corridor.

Tuesday night...Widespread frost and freezes are expected Tuesday
night.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions, according to standard operating procedure.

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 4:34 AM MDTWinter Weather AdvisoryRIWFremont, Hot Springs, Johnson, Lincoln, Park, Sublette and 1 more37 hr
Sep 7, 11:25 AM MDTHigh Wind WarningRIWLincoln, Sublette, Teton17 hr

Nearby

Winter Storm Warnings in Wyoming, 2020Every winter storm warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.