Alert archive / Wyoming / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 65, NWS Riverton, WY

August 9, 2013Natrona County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Aug 9, 2013, 5:39 PM MDT for Natrona County, Wyoming. It was in force for 51 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: Aug 9, 2013, 5:39 PM MDT (23:39 UTC)
Expired: Aug 9, 2013, 6:30 PM MDT
In force: 51 min
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Tornado: Possible
Hail: 1.75 in
Wind: 70.0 mph

County Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 137 km from the middle of the area, began a volume at 23:40 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, 11.7 hours before the alert went out and 131 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: 1 J/kg
Mixed-layer CIN: -264 J/kg
Mixed-layer LCL: 1948 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 72 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 severe thunderstorm 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 severe thunderstorm warning went out at Aug 9, 3:12 PM MDT, 2 hours 27 minutes earlier.

Area forecast discussion, Aug 9, 3:12 PM MDT, 2 hours 27 minutes before

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Hazardous weather outlook, Aug 9, 5:00 AM MDT, 12 hours 39 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
500 AM MDT FRI AUG 9 2013

WYZ001>020-022>030-101100-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
500 AM MDT FRI AUG 9 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED STRONG THUNDERSTORMS WILL BE POSSIBLE
THIS AFTERNOON AND EVENING...MAINLY NORTHEAST OF A LOVELL TO
TO CASPER LINE. THE MAIN THREAT FROM ANY OF THESE STORMS WILL BE
GUSTY WINDS TO 40 MPH AND POSSIBLY SOME PEA TO MARBLE SIZE HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SATURDAY...ISOLATED THUNDERSTORMS WEST...WIDELY SCATTERED
THUNDERSTORMS CENTRAL.

SUNDAY THROUGH WEDNESDAY...ISOLATED THUNDERSTORMS ACROSS THE NORTH
AND EAST CENTRAL.

.SPOTTER INFORMATION STATEMENT...

PLEASE REPORT WINDS OVER 45 MPH AND HAIL OF ANY SIZE. THANK YOU.

TEAM RIVERTON

In the hours before

Special weather statement, Aug 9, 4:01 PM MDT, 1 hour 38 minutes before

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Special weather statement, Aug 9, 4:03 PM MDT, 1 hour 36 minutes before

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Special weather statement, Aug 9, 4:31 PM MDT, 1 hour 8 minutes before

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Special weather statement, Aug 9, 4:54 PM MDT, 45 minutes before

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Special weather statement, Aug 9, 4:55 PM MDT, 44 minutes before

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Special weather statement, Aug 9, 4:57 PM MDT, 42 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 8, 6:34 PM MDT	Special Weather Statement	RIW	Big Horn	26 min
Aug 8, 7:12 PM MDT	Special Weather Statement	RIW	Johnson	48 min
Aug 9, 1:29 PM MDT	Special Weather Statement	RIW	Johnson	46 min
Aug 9, 1:42 PM MDT	Special Weather Statement	RIW	Sublette	48 min
Aug 9, 2:21 PM MDT	Special Weather Statement	RIW	Fremont	54 min
Aug 9, 2:39 PM MDT	Special Weather Statement	RIW		66 min
Aug 9, 2:43 PM MDT	Special Weather Statement	RIW	Natrona	47 min
Aug 9, 3:31 PM MDT	Special Weather Statement	RIW	Natrona	44 min
Aug 9, 3:32 PM MDT	Special Weather Statement	RIW	Hot Springs	43 min
Aug 9, 3:36 PM MDT	Special Weather Statement	RIW		39 min
Aug 9, 4:01 PM MDT	Special Weather Statement	RIW	Natrona	44 min
Aug 9, 4:03 PM MDT	Special Weather Statement	RIW	Fremont	42 min
Aug 9, 4:31 PM MDT	Special Weather Statement	RIW	Natrona	44 min
Aug 9, 4:47 PM MDT	Severe Thunderstorm Warning	RIW	Natrona	58 min
Aug 9, 4:54 PM MDT	Special Weather Statement	RIW	Hot Springs	51 min
Aug 9, 4:55 PM MDT	Special Weather Statement	RIW	Natrona	50 min
Aug 9, 4:57 PM MDT	Special Weather Statement	RIW	Natrona	48 min
Aug 9, 5:53 PM MDT	Special Weather Statement	RIW		37 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2013 Every severe thunderstorm warning in 2013

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.