Alert archive / Wyoming / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 1, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at Apr 25, 2009, 3:41 PM MDT for Sweetwater County, Wyoming. It was in force for 49 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
- Apr 25, 2009, 3:41 PM MDT (21:41 UTC)
- Expired
- Apr 25, 2009, 4:30 PM MDT
- In force
- 49 min
- Issued by
- NWS Riverton, WY
- Area
- Storm-based polygon
County Sweetwater County, WY
The radar
The Riverton/Lander radar (KRIW), 160 km from the middle of the area, began a volume at 21:42 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, 9.7 hours before the alert went out and 162 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 724 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 24 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Apr 25, 3:22 AM MDT, 12 hours 19 minutes earlier.
Area forecast discussion, Apr 25, 3:22 AM MDT, 12 hours 19 minutes before
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</html>Hazardous weather outlook, Apr 25, 3:18 PM MDT, 23 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 318 PM MDT SAT APR 25 2009 WYZ001>020-022>030-261100- 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- 318 PM MDT SAT APR 25 2009 ...WINTER WEATHER ADVISORY FOR CASPER MOUNTAIN TONIGHT... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS SWEETWATER COUNTY...THE SOUTHEAST CORNER OF FREMONT AND THE FAR SOUTHWEST CORNER OF NATRONA COUNTY THROUGH 9 PM THIS EVENING. THE STRONGEST STORMS MAY CONTAIN UP TO ONE HALF INCH HAIL AND FREQUENT LIGHTNING. SNOW WILL ALSO DEVELOP FROM THE GREEN MOUNTAINS AND RATTLESNAKE RANGE OVER TO CASPER AND CASPER MOUNTAIN THIS EVENING AND CONTINUE OVERNIGHT. SNOWFALL COULD BE BRIEFLY HEAVY WITH SNOWFALL RATES AROUND AN INCH PER HOUR. THE HEAVIEST SNOW IS EXPECTED ON CASPER MOUNTAIN WHERE 5 TO 9 INCHES IS EXPECTED. HOWEVER...EVEN THE LOWER ELEVATIONS OF NATRONA COUNTY WILL LIKELY SEE FROM 1 TO 3 INCHES. THE GREEN MOUNTAINS AND RATTLESNAKE RANGE CAN EXPECT 2 TO 5 INCHES WITH 1 TO 3 INCHES ACROSS THE LOWER ELEVATIONS INCLUDING SWEETWATER STATION AND JEFFREY CITY. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SIGNIFICANT SNOWFALL IN THE CENTRAL MOUNTAINS AND BASINS OF WYOMING IS POSSIBLE SUNDAY NIGHT. A STRONG GULF OF ALASKA STORM SYSTEM WILL DIVE SOUTHEASTWARD THROUGH IDAHO ON SUNDAY TO NEAR THE GREEN RIVER AND ROCK SPRINGS AREA SUNDAY NIGHT. THE STRONG SURFACE UPSLOPE FLOW EAST OF THE DIVIDE IS EXPECTED TO BRING WIDESPREAD ACCUMULATING SNOW TO THE ABSAROKA...OWL CREEK AND WIND RIVER MOUNTAINS AS WELL AS THE SOUTHERN BIG HORN BASIN AND WIND RIVER BASIN SUNDAY NIGHT. EARLY INDICATIONS POINT TOWARD 3 TO 5 INCHES ACROSS THE WIND RIVER BASIN AND LANDER FOOTHILLS WITH 5 TO 10 INCHES IN THE SURROUNDING MOUNTAINS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ASKED TO REPORT SNOWFALL AMOUNTS OF AN INCH OR GREATER AND ANY THUNDERSTORMS WITH HAIL. THANK YOU TEAM RIVERTON
In the hours before
Special weather statement, Apr 25, 2:56 PM MDT, 45 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 256 PM MDT SAT APR 25 2009 WYZ030-252145- EAST SWEETWATER COUNTY- 256 PM MDT SAT APR 25 2009 ...SIGNIFICANT WEATHER ADVISORY FOR SWEETWATER COUNTY UNTIL 345 PM MDT... AT 254 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 9 MILES NORTHEAST OF STATE HWY 430 MILE MARKER 20...OR 22 MILES EAST OF ROCK SPRINGS...MOVING NORTHEAST AT 25 MPH. HALF INCH HAIL...AND WINDS AROUND 50 MPH ARE POSSIBLE WITH THIS STORM. RESIDENTS IN CENTRAL SWEETWATER COUNTY...INCLUDING THE LOCATIONS OF I80 EXIT 136...I80 EXIT 139...I80 EXIT 142 AND BITTER CREEK REST AREA...SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN. THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 127 AND 150. 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 SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. C. BAKER
Special weather statement, Apr 25, 3:03 PM MDT, 38 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 303 PM MDT SAT APR 25 2009 WYZ028>030-252145- EAST SWEETWATER COUNTY-FLAMING GORGE-ROCK SPRINGS AND GREEN RIVER- 303 PM MDT SAT APR 25 2009 ...SIGNIFICANT WEATHER ADVISORY FOR SWEETWATER COUNTY UNTIL 345 PM MDT... AT 303 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM NEAR I80 EXIT 102...OR NEAR ROCK SPRINGS...MOVING NORTHEAST AT 20 MPH. HALF INCH HAIL...AND WINDS AROUND 50 MPH ARE POSSIBLE WITH THIS STORM. RESIDENTS IN CENTRAL SWEETWATER COUNTY...INCLUDING THE LOCATIONS OF JCT I80 AND HWY 191...I80 EXIT 102...ROCK SPRINGS...I80 EXIT 111 AND SWEETWATER COUNTY AIRPORT...SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN. THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 95 AND 126. 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 SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. C. BAKER
The office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 25, 3:13 PM MDT | Winter Weather Advisory | RIW | Fremont, Hot Springs, Lincoln, Natrona, Park, Sublette and 2 more | 39 hr |
| Apr 25, 4:27 PM MDT | Severe Thunderstorm Warning | RIW | Sweetwater | 48 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.