Slow moving thunderstorms produced 3 to 4 inches which resulted in flash flooding and mudslides in east central Albany County.
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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.
Slow moving thunderstorms produced 3 to 4 inches which resulted in flash flooding and mudslides in east central Albany County.
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 Aug 22, 2:02 PM MST, 48 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 302 PM MDT THU AUG 22 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 245 PM MDT THU AUG 22 2013 SOME CONVECTION NOW DEVELOPING OVER THE MOUNTAINS BUT NOT MAKING MUCH PROGRESS EASTWARD SO FAR. AS A WEAK IMPULSE OVER WYOMING MOVES NORTHEAST SHOULD SEE SOME ACTIVITY SPREAD INTO THE PLAINS INTO EARLY THIS EVENING BEFORE DISSIPATING WITH LOSS OF HEATING. LITTLE CHANGE SEEN IN THE OVERALL WEATHER PATTERN ACROSS THE CWA FRIDAY THROUGH SATURDAY AS A SUBTROPICAL PLUME OF MOISTURE WILL CONTINUE TO FLOW AROUND AN UPPER HIGH OVER THE SOUTHERN PLAINS. THIS MOISTURE WILL INTERACT WITH WEAK IMPULSES AND AFTERNOON INSTABILITY TO PRODUCE ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS AND STORMS ON A WIDELY SCATTERED BASIS FRIDAY. THE MOISTURE LOOKS LIKE IT MAY GET SHUNTED A BIT MORE WEST SATURDAY THUS ACTIVITY THEN LOOKS TO BE MORE OVER WYOMING WITH WARMING MID LEVEL TEMPS OVER THE PANHANDLE HINDERING CONVECTION. SHEAR VALUES WILL REMAIN RATHER LOW SO ACTIVITY SHOULD BE NON-SEVERE. TEMPERATURES WARM AGAIN FRIDAY THEN QUITE WARM ON SATURDAY... ESPECIALLY OVER THE PANHANDLE WHERE MAXS MAY REACH 100 IN SOME SPOTS UNDER A NICE THICKNESS RIDGE. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 245 PM MDT THU AUG 22 2013 WEATHER PATTERN WILL SEE LITTLE VARIATION THROUGH THE EXTENDED FORECAST PERIOD. UPPER LEVEL RIDGE WILL COVER A VAST MAJORITY OF THE CONUS WITH THE RIDGE AXIS OVER THE PLAINS. UPPER TROUGH WILL HANG ALONG THE WEST COAST. THIS WILL PLACE THE FORECAST AREA UNDER SOUTHWEST FLOW ALOFT WITH OCCASIONAL SHORTWAVE TROUGHS SLIDING THROUGH THE FLOW. SHORTWAVES WILL ENHANCE CHANCES FOR PRECIPITATION BUT IT DOES APPEAR HIGHER ELEVATIONS WILL SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS NEARLY EVERY AFTERNOON AS MID AND UPPER LEVEL MONSOON MOISTURE TRACKS OUT OF THE SOUTHWEST CONUS. LOW LEVEL MOISTURE MAY ALSO BE IN PLAY THROUGH THE EXTENDED PERIOD. SURFACE HIGH PRESSURE ENTRENCHED OVER THE SOUTHEAST CONUS WILL CONTINUE TO PUMP LOW LEVEL MOISTURE INTO THE PLAINS. THE ONLY QUESTION FROM DAY TO DAY WILL BE THE LOCATION OF THE LEE TROUGH INTO THE ROCKIES. CERTAINLY MOISTURE MAY GET PULLED WESTWARD UP ALONG THE LARAMIE RANGE...SUCH THAT SOME STRONGER STORMS AND HEAVY RAIN MAY BE CONCERN A FEW DAYS. THE OTHER POTENTIAL CONCERN IS WITH THE TROPICAL DEPRESSION NINE-E IN THE EASTERN PACIFIC WHICH WEST OF THE MEXICAN COAST. SOME MODELS ARE PULLING REMNANTS OF THIS SYSTEM NORTHWARD INTO THE AREA LATE THIS WEEKEND OR EARLY NEXT WEEK. WILL HAVE TO SEE HOW IT PLAYS OUT BUT COULD POTENTIALLY BRING A SHOT OF WIDESPREAD RAIN TO THE FORECAST AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING) ISSUED AT 1134 AM MDT THU AUG 22 2013 ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE FORECAST AREA THIS AFTERNOON AND EVENING. SEVERE THUNDERSTORMS ARE NOT EXPECTED BUT SMALL HAIL AND WIND ARE POSSIBLE FOR AREAS ALONG AND EAST OF INTERSTATE 25...INCLUDING INTO THE NEBRASKA PANHANDLE. SHOWERS AND THUNDERSTORMS WILL END FOR WEST TO EAST WITH MOST ACTIVITY ENDING BY 06Z. FOG MAY AGAIN DEVELOP INTO THE NEBRASKA PANHANDLE LATE TONIGHT. FOG MAY PRODUCE LIFR VISIBILITY AND CEILINGS. && .FIRE WEATHER... ISSUED AT 245 PM MDT THU AUG 22 2013 CONCERNS TO REMAIN MINIMAL INTO EARLY NEXT WEEK WITH WEATHER CONDITIONS EXPECTED TO BE NON-CRITICAL. WIDELY SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL PERSIST MAINLY OVER SE WYOMING INTO EARLY NEXT WEEK BUT DRY LIGHTNING NOT EXPECTED. TEMPERATURES WILL STAY WARM WITH GENERALLY LIGHT WINDS OUTSIDE OF STORMS WHERE BRIEF GUSTY WINDS ARE POSSIBLE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && SHORT TERM...RE LONG TERM...LIEBL AVIATION...LIEBL FIRE WEATHER...RE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1030 AM MDT THU AUG 22 2013 WYZ101>119-231215- CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY- NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS- SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY- SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE- LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS- CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY- 1030 AM MDT THU AUG 22 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS SOUTHEAST WYOMING THIS AFTERNOON...ESPECIALLY ALONG THE INTERSTATE 80 CORRIDOR AND THE MOUNTAINS. GUSTY WINDS AND HEAVY RAINFALL ARE EXPECTED WITH THESE THUNDERSTORMS INTO THIS EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE MOST DAYS ACROSS SOUTHEAST WYOMING...ESPECIALLY OVER THE MOUNTAINS. SEVERE THUNDERSTORMS ARE NOT EXPECTED. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE NEZ002-003-019>021-054-055-095-096-231215- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 1030 AM MDT THU AUG 22 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...TODAY AND TONIGHT WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE BY LATE THIS AFTERNOON BEFORE ENDING DURING THE EVENING. BRIEF HEAVY RAINFALL AND GUSTY WINDS MAY ACCOMPANY THESE THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY ISOLATED THUNDERSTORMS ARE POSSIBLE FRIDAY AND SATURDAY . NO SEVERE WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 240 PM MDT THU AUG 22 2013 WYZ106-116-222145- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY WY-SOUTH LARAMIE RANGE WY- 240 PM MDT THU AUG 22 2013 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN PLATTE AND EASTERN ALBANY COUNTIES UNTIL 345 PM MDT... AT 238 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 17 MILES NORTH OF BALDY PEAK...OR 29 MILES SOUTHWEST OF WHEATLAND...MOVING EAST AT 15 MPH. WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... MAINLY RURAL AREAS OF EXTREME EASTERN ALBANY AND SOUTHWESTERN PLATTE COUNTIES. IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. && LAT...LON 4190 10516 4166 10512 4169 10544 4185 10548 TIME...MOT...LOC 2040Z 261DEG 11KT 4177 10536 CLAYCOMB
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
324 PM MDT THU AUG 22 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0316 PM FLASH FLOOD 19 NE BOSLER 41.77N 105.43W
08/22/2013 ALBANY WY LAW ENFORCEMENT
MUDSLIDE AT MILE MARKER 22 ON STATE HIGHWARY 34. NEAR THE
SYBILLE WILDLIFE RESEARCH CENTER.
&&
LIEBLThe Cheyenne radar (KCYS), 86 km away, was scanning. The volume nearest the first event began at 21:51 UTC.
1 flash flood. Local standard time, as filed.
Flash flooding occurred along Highway 34 between mile markers 19 and 27 northeast of Bosler. A mudslide was reported at mile marker 22 about three miles southwest of the Sybille Wildlife Research Center.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2013Every state in 2013This day in weather historyWarnings in Wyoming, August 2013
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: 466754.