Alert archive / Wyoming / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 23, NWS Riverton, WY

June 30, 2009Teton County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jun 30, 2009, 5:12 PM MDT for Teton County, Wyoming. It was in force for 63 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
Jun 30, 2009, 5:12 PM MDT (23:12 UTC)
Expired
Jun 30, 2009, 6:15 PM MDT
In force
63 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon

County Teton County, WY

The radar

The Pocatello radar (KSFX), 193 km from the middle of the area, began a volume at 23:13 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, 11.2 hours before the alert went out and 201 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 2009-06-30Temperature 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 2009-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 39 square meters per square second.193958Sfc1 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
2371 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
152 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 Jun 30, 3:34 PM MDT, 1 hour 38 minutes earlier.

Area forecast discussion, Jun 30, 3:34 PM MDT, 1 hour 38 minutes before
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Hazardous weather outlook, Jun 30, 5:00 AM MDT, 12 hours 12 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
500 AM MDT TUE JUN 30 2009

WYZ001>020-022>030-011100-
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 TUE JUN 30 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE EXPECTED AGAIN OVER MUCH OF THE THIS AFTERNOON AND
EVENING.  THEY WILL BE MOST NUMEROUS OVER THE NORTHWEST.  THE MAIN
HAZARDS WILL BE LIGHTNING AND GUSTY WINDS TO 50 MPH...THOUGH SOME
HEAVY RAIN AND SMALL HAIL ARE POSSIBLE OVER THE NORTHWEST.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A DISTURBANCE WILL MOVE ACROSS SOUTHERN WYOMING WEDNESDAY BRINGING
WITH IT SOME THUNDERSTORMS.  A COLD FRONT WILL MOVE THROUGH BEHIND
THE DISTURBANCE BRINGING COOLER TEMPERATURES AND INCREASED
HUMIDITY.  THIS WILL RAISE THE POTENTIAL FOR HEAVY RAINFALL WITH
THUNDERSTORMS WEDNESDAY AND THURSDAY AFTERNOONS AND EVENINGS.

AT LEAST ISOLATED THUNDERSTORMS ARE EXPECTED FRIDAY AS
MONSOONAL MOISTURE ROTATES NORTHEAST ACROSS THE AREA. LATER
FRIDAY INTO FRIDAY NIGHT...A COLD FRONT MAY DROP SOUTH AND SET THE
STAGE FOR SOME STRONGER THUNDERSTORM OVER THE WEEKEND EAST OF
THE CONTINENTAL DIVIDE. THUNDERSTORM COVERAGE WILL LIKELY DECREASE
MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ASKED TO REPORT ANY WIND GUSTS IN EXCESS OF 40 MPH OR
HAIL WITH THUNDERSTORMS.  THANK YOU.

TEAM RIVERTON

In the hours before

Special weather statement, Jun 30, 1:08 PM MDT, 4 hours 4 minutes before
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Special weather statement, Jun 30, 4:54 PM MDT, 18 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
454 PM MDT TUE JUN 30 2009

WYZ012-013-302345-
JACKSON HOLE-TETON AND GROS VENTRE MOUNTAINS-
454 PM MDT TUE JUN 30 2009

...SIGNIFICANT WEATHER ADVISORY FOR TETON COUNTY AND GRAND TETON
NATIONAL PARK UNTIL 545 PM MDT...

AT 449 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM ABOUT 10 MILES WEST
OF COLTER BAY VILLAGE...SOUTHWEST THROUGH THE GRAND TARGHEE SKI AREA
TO ABOUT 10 MILES WEST OF JACKSON...MOVING NORTHEAST AT 20 MPH.

ONE HALF INCH DIAMETER HAIL...AND WINDS AROUND 45 MPH ARE POSSIBLE
WITH THESE STORMS. DANGEROUS CLOUD-TO-GROUND LIGHTNING IS POSSIBLE
WITH THESE STORMS.

RESIDENTS AND VISITORS IN TETON COUNTY AS WELL AS GRAND TETON
NATIONAL PARK...INCLUDING THE LOCATIONS OF GRAND TARGHEE SKI
AREA...FONDA POINT CAMPGROUND...MOUNT MORAN...TETON PASS...MOOSE
...MORAN BAY...GRAND TETON...JACKSON AND LEIGH LAKE...SHOULD
MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS
AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER
THREATEN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE INDOORS IMMEDIATELY AS THIS STORM APPROACHES YOUR LOCATION. THIS
IS A POTENTIALLY DANGEROUS STORM. IF YOU ARE IN ITS PATH...YOU SHOULD
BE PREPARED FOR GUSTY WINDS...HAIL...AND DEADLY CLOUD TO GROUND
LIGHTNING. IF A STURDY STRUCTURE IS NOT AVAILABLE...SEEK SHELTER IN A
VEHICLE WITH THE WINDOWS UP.

&&

REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.

LAT...LON 4371 11106 4409 11082 4413 11024 4362 11057
      4331 11069 4329 11105
TIME...MOT...LOC 2250Z 265DEG 16KT 4402 11074 4361 11100
          4337 11110

MURRELL

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 7:47 PM MDTSpecial Weather StatementRIWTeton58 min
Jun 29, 8:07 PM MDTSpecial Weather StatementRIW38 min
Jun 29, 8:27 PM MDTSpecial Weather StatementRIW48 min
Jun 29, 8:37 PM MDTSpecial Weather StatementRIWTeton38 min
Jun 29, 9:16 PM MDTSpecial Weather StatementRIWTeton29 min
Jun 30, 10:15 AM MDTSpecial Weather StatementRIWHot Springs45 min
Jun 30, 11:09 AM MDTSpecial Weather StatementRIWWashakie36 min
Jun 30, 1:08 PM MDTSpecial Weather StatementRIWJohnson22 min
Jun 30, 4:54 PM MDTSpecial Weather StatementRIWTeton51 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2009Every severe thunderstorm warning in 2009

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.