Alert archive / Wyoming / Flash Flood Warnings in 2013

Flash Flood Warning 12, NWS Riverton, WY

August 12, 2013Natrona County, Wyoming

NWS Riverton, WY issued this flash flood warning at Aug 12, 2013, 9:20 PM MDT for Natrona County, Wyoming. It was in force for 3 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: Aug 12, 2013, 9:20 PM MDT (03:20 UTC)
Expired: Aug 13, 2013, 12:00 AM MDT
In force: 3 hr
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Flood severity: None

County Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 137 km from the middle of the area, began a volume at 03:22 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 00:00Z, 3.3 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: 40 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 3441 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: -4 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 flash flood 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 flash flood warning went out at Aug 12, 2:32 PM MDT, 6 hours 48 minutes earlier.

Area forecast discussion, Aug 12, 2:32 PM MDT, 6 hours 48 minutes before

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Hazardous weather outlook, Aug 12, 5:07 AM MDT, 16 hours 13 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
507 AM MDT MON AUG 12 2013

WYZ001>020-022>030-131200-
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-
507 AM MDT MON AUG 12 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED THUNDERSTORMS MAINLY ACROSS THE NORTH AND EAST CENTRAL
FORECAST AREA.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SATURDAY

TUESDAY...ISOLATED STRONG TO SEVERE STORMS POSSIBLE ACROSS JOHNSON
AND NORTHEAST NATRONA COUNTIES.

.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 12, 5:10 PM MDT, 4 hours 10 minutes before

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Special weather statement, Aug 12, 9:05 PM MDT, 15 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 12, 9:05 PM MDT	Special Weather Statement	RIW	Natrona	40 min
Aug 13, 2:18 PM MDT	Special Weather Statement	RIW		57 min
Aug 13, 2:33 PM MDT	Special Weather Statement	RIW	Natrona	42 min
Aug 13, 2:58 PM MDT	Special Weather Statement	RIW		47 min
Aug 13, 4:50 PM MDT	Special Weather Statement	RIW	Natrona	40 min
Aug 13, 5:02 PM MDT	Special Weather Statement	RIW	Washakie	43 min
Aug 13, 5:17 PM MDT	Special Weather Statement	RIW	Sweetwater	43 min

Nearby

Flash Flood Warnings in Wyoming, 2013 Every flash flood 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.