Alert archive / Wyoming / Severe Thunderstorm Warnings in 2007
Severe Thunderstorm Warning 78, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at Aug 23, 2007, 6:50 PM MDT for Natrona County, Washakie County, Wyoming. It was in force for 55 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 23, 2007, 6:50 PM MDT (00:50 UTC)
- Expired
- Aug 23, 2007, 7:45 PM MDT
- In force
- 55 min
- Issued by
- NWS Riverton, WY
- Area
- Counties, with a storm outline in the text
Counties Natrona County, WY, Washakie County, WY
The radar
The Riverton/Lander radar (KRIW), 108 km from the middle of the area, began a volume at 00:51 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
Salt Lake City I, UT (KSLC), launched 00:00Z, 0.8 hours before the alert went out and 484 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
- 3271 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 29 m²/s²
- 0-3 km storm-relative helicity
- 122 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 Aug 23, 2:31 PM MDT, 4 hours 19 minutes earlier.
Area forecast discussion, Aug 23, 2:31 PM MDT, 4 hours 19 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 231 PM MDT THU AUG 23 2007 .SHORT TERM...TONIGHT THROUGH SUNDAY CONVECTION IS OCCURRING OVER THE AREA AS INSTABILITY IS INCREASING. A SHORTWAVE IS EVIDENT ON SATL PICS WITH SOME UPPER LEVEL DIVERGENCE FORECASTED AS THE WAVE MOVES INTO THE ROCKIES TONIGHT. HAVE RAISED THE PRECIP CHANCE OVER THE NORTH AND NORTHEAST ZONES TONIGHT THRU 12Z FRIDAY. WOULD EXPECT THE ACTIVITY TO END IN THE WEST AND CENTRAL AROUND MIDNIGHT. ON FRIDAY THE SHORTWAVE COULD STILL BRING SOME SHOWERS TO THE NE ZONES UNTIL 18Z...THEN THE DRYING SHOULD WORK INTO THAT AREA...WITH COOL HIGHS. REST OF THE REGION WILL BE DRY FRIDAY WITH WARMER HIGHS THAN TODAY. WEST NORTHWEST FLOW FOR SATURDAY WITH DRY WEATHER AND LIGHT WIND. HIGH TEMPS WILL WARM AS WELL. ON SUNDAY THE RIDGE AXIS WILL PASS THROUGH WY WITH A WEST SOUTHWEST FLOW ALOFT AND LEE TROF FORMING. THIS WILL BRING SOME WIND TO THE FAVORED AREAS OF THE CENTRAL AND SOUTH. WARMER AS WELL ON SUNDAY WITH ONLY ISOLATED AFTERNOON STORMS OVER THE NW ZONES. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY MEDIUM-RANGE MODELS CONTINUE TO SHOW DECREASING SPREAD IN HANDLING ENERGY MOVING ACROSS GULF OF ALASKA THIS MORNING. THUS FOR THIS PERIOD UPPER TROUGH WILL MOVE ACROSS THE NORTHERN ROCKIES SUNDAY NIGHT AND MONDAY. SOME SHOWERS AND THUNDERSTORMS MAY CLIP THE YELLOWSTONE NATIONAL PARK AREA WITH SURFACE COLD FRONT PUSHING ACROSS THE AREA SUNDAY NIGHT AND MONDAY. UPPER RIDGE THEN BUILDS INTO THE INTERIOR WEST BEHIND THIS TROUGH WITH GFS SHOWING SOME SUB-TROPICAL MOISTURE ALONG WITH EMBEDDED DISTURBANCES ROTATING THROUGH THE GREAT BASIN ACROSS SOUTHERN WYOMING. THUS...THE BEST CHANCES OF THUNDERSTORMS TUESDAY THROUGH THURSDAY WILL BE PRIMARILY ALONG AND SOUTH OF A CPR-RKS LINE. ABOVE NORMAL TEMPERATURES SUNDAY WILL BE FOLLOWED BY NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES TO CLOSE OUT AUGUST 2007. && .AVIATION... SCATTERED THUNDERSTORMS WILL CONTINUE THIS EVENING...MOST NUMEROUS IN AND NEAR THE MOUNTAINS...WITH A FEW LINGERING SHOWERS OVERNIGHT. VISIBILITIES COULD BRIEFLY DROP BELOW 3 STATUTE MILES IN HEAVY RAIN AT THE SURFACE NEAR THE THUNDERSTORMS...AREAS THAT RECEIVE HEAVY RAIN THIS EVENING CAN EXPECT IFR CONDITIONS IN THE LOWER VALLEYS WITH LOW CEILINGS AND VISIBILITY IN AREAS OF FOG LATER TONIGHT AND FRIDAY MORNING. WESTERLY FLOW WILL DECREASE MOISTURE ACROSS THE AREA ON FRIDAY LIMITING THUNDERSTORMS TO ISOLATED COVERAGE. && .FIRE WEATHER...SHOWERS AND STORMS WILL OCCUR THIS EVENING OVER THE FIRE ZONES WITH THE BEST COVERAGE OVER THE NORTH AND EAST ZONES. SHOWERS WILL OCCUR OVER THE NORTH AND EAST ZONES AFTER MIDNIGHT WHILE THE REST OF THE AREA SEES DECREASING CLOUDS. SOME SHOWERS WILL PERSIST OVER THE NORTHEAST FIRE ZONES FRIDAY MORNING...WITH SOME DRYING IN THE AFTERNOON. ELSEWHERE FRIDAY...DRY WEATHER WILL OCCUR WITH A MOSTLY SUNNY SKY. THE DRYING TREND WILL CONTINUE INTO SATURDAY AND SUNDAY WITH WARMING TEMPERATURES AND LOWER AFTERNOON HUMIDITY. THE WIND WILL INCREASE SOME ON SUNDAY WITH A LEE SIDE TROUGH FORMING. THERE MAY BE SOME CONCERN ON SUNDAY IN THE SOUTHERN FIRE ZONES DUE TO CRITICAL DRY FUELS. WILL ADDRESS THIS IN THE COMING DAYS. && .RIW WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...AR LONG TERM...AEM AVIATION...C.BAKER FIRE WEATHER...AR
Hazardous weather outlook, Aug 23, 5:49 PM MDT, 1 hour 1 minute before
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Local storm report, Aug 23, 5:41 PM MDT, 1 hour 9 minutes before
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</html>Special weather statement, Aug 23, 6:04 PM MDT, 46 minutes before
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</html>Nearby
Severe Thunderstorm Warnings in Wyoming, 2007Every severe thunderstorm warning in 2007
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.