For a second day in a row severe thunderstorms moved across parts of far southeastern Wyoming and produced hail and some tornadoes. The tornadoes remained generally over open country.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
For a second day in a row severe thunderstorms moved across parts of far southeastern Wyoming and produced hail and some tornadoes. The tornadoes remained generally over open country.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Cheyenne, WY wrote its last area forecast discussion before the first event at May 23, 2:11 AM MST, 10 hours 14 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 311 AM MDT FRI MAY 23 2008 .SHORT TERM...TODAY THRU SATURDAY NIGHT... OVERALL PATTERN HAS NOT CHANGED MUCH FROM YESTERDAY WITH STRONG UPPER LOW HOLDING OVER THE WRN CONUS WITH UPPER IMPULSES AND SPEED MAXES EJECTING NORTHWARD OVER THE ROCKY MTNS AND ADJACENT HIGH PLAINS LIKELY TO PRODUCE ANOTHER ROUND OF TSTRMS TODAY...WITH SOME STORMS LIKELY SEVERE AGAIN PRIMARILY OVER THE SRN NEB PANHANDLE WHERE SFC BOUNDARY WILL EXIST EAST OF SFC LOW WHICH SHOULD BE SOMEWHERE OVER EXTREME NE COLORADO. WILL HAVE TO WATCH AREAS THAT RECEIVED HEAVY RAINS FROM YESTERDAYS CONVECTION FOR POTENTIAL FLOODING PROBLEMS IF MORE HEAVY RAINS MOVE ACROSS THOSE SAME AREAS. ACTIVITY WILL DECREASE THIS EVENING AS SIG PIECE OF UPPER LOW BREAKS OFF AND LIFTS INTO THE NORTHERN HIGH PLAINS ALONG WITH SFC LOW AND ALLOWS SFC BOUNDARY TO PUSH EAST. EXPECT LESS ACTIVITY SATURDAY AS CWA BASICALLY WILL BE IN BETWEEN THE TWO UPPER LOWS WITH SOME DRIER AIR AND LESS INSTABILITY SPREADING OVER THE REGION. WILL STILL MAINTAIN LOW POPS OVER THE CWA AS MID LEVELS OF THE ATMOSPHERE WILL STILL BE RATHER COOL BUT SEVERE POTENTIAL WILL BE FURTHER EAST. .LONG TERM...SUNDAY THROUGH THURSDAY. AN UPPER LEVEL LOW IS FORECAST...WITH FAIRLY GOOD MODEL AGREEMENT...TO MOVE SOUTH OVER HUDSON BAY BY SUNDAY AND THIS FEATURE SHOULD BE THE TRIGGER TO BREAK DOWN THE OMEGA BLOCKING PATTERN IN PLACE ACROSS THE CONTINENTAL UNITED STATES. EVEN AS THE UPPER TROUGH OVER THE WEST OPENS UP...JET ENERGY WILL CONTINUE TO BRING SHORT-WAVE DISTURBANCES ACROSS SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE AND THEREFORE HAVE INCREASED PRECIPITATION CHANCES OVER MUCH OF THE AREA CLOSER TO CLIMATOLOGICAL VALUES. TEMPERATURES WILL BE GENERALLY WITHIN 5 TO 8 DEGREES OF NORMAL VALUES THROUGH THE PERIOD...WITH MID 60S TO MID 70S FOR EXPECTED AFTERNOON HIGHS. && .AVIATION... MAINLY MVFR/LOCAL IFR CONDITIONS OVR MUCH OF THE SE WY PLAINS INTO THE NEB PANHANDLE TODAY DUE TO LOW CIGS WITH IMPROVING CONDITIONS TONIGHT. SHOWERS AND TSTRMS INCRG TODAY THEN GRADUALLY DIMINISHING TONIGHT. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...FLOOD WATCH UNTIL 6 PM FRIDAY FOR WYZ061-WYZ063. NE...NONE. && SHORT TERM/AVIATION...RE LONG TERM....SJC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1020 AM MDT FRI MAY 23 2008 NEZ001>003-019>021-054-055-WYZ059>070-241145- SIOUX-DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL- CHEYENNE-CONVERSE-NIOBRARA-SOUTHWEST CARBON-NORTH CARBON- SNOWY RANGE-NORTH LARAMIE RANGE-LARAMIE VALLEY-LARAMIE RANGE- PLATTE-GOSHEN-CHEYENNE FOOTHILLS-PINE BLUFFS- 1020 AM MDT FRI MAY 23 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE AND SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP THIS AFTERNOON. SOME THUNDERSTORMS ARE EXPECTED TO BE SEVERE OVER THE NEBRASKA PANHANDLE...WITH A SLIGHT RISK OF SEVERE STORMS EAST OF THE LARAMIE RANGE IN WYOMING. THE MAIN THREAT WITH THE STORMS WILL BE LARGE HAIL...WITH A TORNADO POSSIBLE IN THE NEBRASKA PANHANDLE. A FLOOD WARNING REMAINS IN EFFECT FOR MUCH OF PLATTE COUNTY WYOMING THROUGH FRIDAY AS ADDITIONAL RAINFALL AND EXISTING HIGH WATER LEVELS WILL PRODUCE CONTINUED FLOODING OVER PORTIONS OF THE COUNTY. ANOTHER FLOOD WARNING REMAINS IN EFFECT FOR THE LITTLE SNAKE RIVER IN FAR SOUTHWEST CARBON COUNTY THROUGH 300 PM MDT TODAY. THE FLOOD WATCH CONTINUES FOR CENTRAL AND SOUTHERN PARTS OF CARBON COUNTY THROUGH FRIDAY. THERE IS A CONCERN THAT ADDITIONAL SHOWERS DURING THAT TIME COULD CAUSE SOME RIVERS AND STREAMS ALREADY SWOLLEN WITH SNOW MELT RUNOFF TO FLOOD. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE WILL BE A CHANCE OF THUNDERSTORMS EACH DAY AS DISTURBANCES MOVE THROUGH THE UPPER LEVEL TROUGH TO THE WEST ALONG THE PACIFIC COAST. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY AND TONIGHT...ESPECIALLY IN THE NEBRASKA PANHANDLE AND EXTREME SOUTHEAST WYOMING. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
The Cheyenne radar (KCYS), 9 km away, was scanning. The volume nearest the first event began at 19:23 UTC.
4 hail, 4 tornado. Local standard time, as filed.
Many reports of hail nickel to quarter size over the far eastern portions of town.
Reports of hail around 1.00 inch in diameter from second storm that moved just east of Cheyenne.
Tornado tracked over open country.
Tornado remained over open country.
Reports of hail from nickel to quarter size along track from near Wheatland to Guernsey, WY.
Tornado tracked northward over open country.
Tornado moved primarily over open country, but removed a roof from a mobile home.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2008Every state in 2008This day in weather historyThe tornado archive for Wyoming, 2008Warnings in Wyoming, May 2008
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 90695, 90696, 90689, 90690, 90697, 90691, 90698, 90694.