Strong winds from an afternoon thunderstorm damaged power poles in southwest Goshen 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.
Strong winds from an afternoon thunderstorm damaged power poles in southwest Goshen 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 Jul 12, 10:59 AM MST, 3 hours 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 1159 AM MDT FRI JUL 12 2013 .UPDATE... ISSUED AT 1136 AM MDT FRI JUL 12 2013 THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE WHEN AND WHERE THE BEST SHOWER AND THUNDERSTORM POTENTIAL WILL BE THIS AFTERNOON. LATEST SATELLITE LOOP CONTINUES TO SHOW MID AND HIGH CLOUDS INFLUENCING AREAS MAINLY IN WYOMING EAST OF THE LARAMIE RANGE. THESE CLOUDS ARE SHOWING SOME SIGNS OF BREAKING UP IN COLORADO...BUT WE MAY START SEEING SHOWERS AND THUNDERSTORMS DEVELOP ALONG THE FRONT RANGE DURING THE NEXT HOUR OR TWO. MEANWHILE...AREAS WEST OF THE LARAMIE RANGE THE SUN HAS BEEN PREDOMINATELY INFLUENCING THAT REGION THIS MORNING WHICH SHOULD RESULT IN THEM REACHING THERE CONVECTIVE TEMPERATURES SOON. AS A RESULT...TODAY WE HAVE KEPT HIGH CHANCES GOING MAINLY WEST OF I-25 THROUGH THE AFTERNOON. HOWEVER...WE MAY START SEEING SOME OF THIS CONVECTION SLOWLY MOVE ITS WAY EAST THIS AFTERNOON AS A SURFACE LOW DEVELOPS IN NORTHEAST CO. AND YIELDS TO SOME SURFACE CONVERGENCE IN SOUTHEAST WYOMING AND NEBRASKA PANHANDLE. OTHERWISE...WE HAVE BUMPED UP TEMPERATURES A BIT IN THE SOUTHERN PANHANDLE THIS AFTERNOON AND DROPPED HIGHS A BIT IN EXTREME SOUTHEAST WYOMING WHERE THE CLOUDS ARE IN PLACE. .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 255 AM MDT FRI JUL 12 2013 TODAY...WATER VAPOR IMAGERY SHOWS AN INCREASING MONSOONAL MOISTURE FLOW OVER OUR REGION. SOUTHWEST FLOW ALOFT CONTINUES. WEAK SHORTWAVE TROUGH ALOFT PASSAGE TODAY AROUND PEAK HEATING WILL COINCIDE WITH SURFACE LOW DEVELOPMENT OVER EASTERN COLORADO...ENHANCING UPSLOPE SOUTHEAST WINDS TO THE LEE OF THE LARAMIE RANGE. THUS...WILL SEE SCATTERED TO NUMEROUS AFTERNOON SHOWERS AND THUNDERSTORMS DEVELOP ALONG AND WEST OF INTERSTATE 25...WITH MORE ISOLATED COVERAGE TO THE EAST. SOME LOCALLY HEAVY RAIN IS EXPECTED DUE TO SLOW STEERING WINDS. TONIGHT...DECENT COVERAGE OF EVENING SHOWERS AND THUNDERSTORMS WITH MOIST SOUTHWEST FLOW ALOFT...THEN AREAL COVERAGE SHOULD DECREASE SIGNIFICANTLY AFTER MIDNIGHT IN THE ABSENCE OF MESOSCALE AND SYNOPTIC LIFTING MECHANISMS. SATURDAY...ANOTHER ISOLATED TO SCATTERED COVERAGE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IN MOIST SOUTHWEST FLOW ALOFT... AND WITH MOIST UPSLOPE IN THE LOW LEVELS TO THE LEE OF THE LARAMIE RANGE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 330 AM MDT FRI JUL 12 2013 THE 00Z DETERMINISTIC/ENSEMBLE MODEL GUIDANCE ARE IN GOOD AGREEMENT EXPANDING THE UPPER RIDGE ACROSS MUCH OF NOAM. A CLOSED MID LEVEL LOW WILL RETROGRADE WESTWARD UNDERNEATH THE RIDGE FROM THE OHIO VALLEY THROUGH THE SOUTHERN PLAINS AND ROCKIES INTO EARLY NEXT WEEK. SUBTROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHEAST IN THE SOUTHWEST FLOW ALOFT OVER THE CWFA...WITH LESSER CONTRIBUTION FROM THE AFOREMENTIONED LOW. THE MOISTURE IN CONCERT WITH WEAK EMBEDDED SHORTWAVES WILL RESULT IN SCATTERED MAINLY DIURNAL CONVECTION SATURDAY NIGHT THROUGH MONDAY NIGHT. PRECIPITABLE WATER VALUES WILL RANGE FROM 1 TO 1.25 INCHES. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH SLOW MOVING TSTORMS. ISOLATED STRONG TO SEVERE TSTORMS WILL BE POSSIBLE SUNDAY WITH GFS SBCAPES OF 1000 TO 2000 J/KG AND 0-6KM SHEAR VALUES OF 30 TO 40 KT EAST OF THE LARAMIE RANGE DURING THE AFTERNOON. THE LIMITING FACTOR MAY BE WARM MID LEVELS WITH 700MB TEMPERATURES NEAR 15 CELSIUS. WARMER TEMPERATURES ALOFT TUESDAY THROUGH THURSDAY SHOULD LIMIT THE COVERAGE OF DIURNAL CONVECTION TO ISOLATED OVER THE MOUNTAINS. 700MB TEMPERATURES IN THE MID TO UPPER TEENS CELSIUS WILL YIELD AFTERNOON HIGHS IN THE UPPER 80S TO MID 90S LOWER ELEVATIONS WITH 70S TO LOWER 80S MOUNTAINS AND HIGH VALLEYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY MORNING) ISSUED AT 1136 AM MDT FRI JUL 12 2013 MONSOON MOISTURE WILL START AFFECTING SEVERAL OF THE TAF SITES THIS AFTERNOON. THE BEST CHANCE FOR CONVECTION AT THIS POINT LOOKS TO BE IN LARAMIE EARLY ON...SINCE THEY SHOULD BE REACHING THERE CONVECTIVE TEMPERATURE THE EARLIEST. WE WENT AHEAD AND ADDED A TEMPO GROUP FOR THAT TAF SITE. BEYOND 20Z...IT IS DIFFICULT TO SAY HOW FAST THIS CONVECTION WILL SHIFT EAST. STEERING FLOW OF THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BE SOUTHWEST TO NORTHEAST AROUND 10KTS. HOWEVER...THE MODELS ARE TRYING TO KEEP IN ON A BOUNDARY DEVELOPING SOMEWHERE BETWEEN CHEYENNE AND SCOTTSBLUFF AFTER 21Z IN ASSOCIATION WITH A SURFACE LOW IN COLORADO. IF THIS BOUNDARY DOES DEVELOP AND MOVE SOUTHEAST...THE SFC FLOW SHOULD SWITCH AROUND TO NORTH LATE THIS AFTERNOON MAINLY EAST OF CYS AND PUSH THROUGH BFF AND SNY BETWEEN 22Z AND 01Z ALONG WITH A CHANCE OF THUNDERSTORMS. COX && .FIRE WEATHER... ISSUED AT 255 AM MDT FRI JUL 12 2013 LESSER CONCERNS TODAY AND SATURDAY DUE TO COOLER TEMPERATURES AND INCREASED LOW LEVEL MOISTURE PRODUCING HIGHER HUMIDITIES. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && UPDATE...REC SHORT TERM...RUBIN LONG TERM...JAMSKI AVIATION...REC FIRE WEATHER...RUBIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 115 PM MDT FRI JUL 12 2013 WYZ101>119-131115- 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- 115 PM MDT FRI JUL 12 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING... SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP AND MOVE NORTHEAST ACROSS THE AREA. SOME OF THE STORMS MAY PRODUCE WIND GUSTS TO 50 MPH AND SMALL HAIL. HOWEVER...THE MAIN THREAT WILL BE TORRENTIAL RAINFALL WITH RAINFALL RATES OF 1 TO 3 INCHES PER HOUR. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED SATURDAY THROUGH MONDAY. A FEW STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE SUNDAY AFTERNOON FOR PORTIONS OF EAST CENTRAL WYOMING. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE OVER THE MOUNTAINS TUESDAY THROUGH THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE REQUIRED 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>021-054-055-095-096-131115- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 115 PM MDT FRI JUL 12 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP AND MOVE NORTHEAST ACROSS THE AREA. A FEW OF THE STORMS MAY PRODUCE WIND GUSTS TO 50 MPH...SMALL HAIL AND TORRENTIAL RAINFALL. RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WILL ALSO BE POSSIBLE WITH THE MORE INTENSE STORMS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED SATURDAY THROUGH MONDAY. A FEW STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE SUNDAY AFTERNOON FOR THE NORTHERN PANHANDLE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE REQUIRED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE COX/JAMSKI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 113 PM MDT FRI JUL 12 2013 WYZ103-106-115-122015- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY WY-LARAMIE VALLEY WY-NORTH LARAMIE RANGE WY- 113 PM MDT FRI JUL 12 2013 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL ALBANY COUNTY UNTIL 215 PM MDT... AT 106 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10 MILES NORTHEAST OF BOSLER...OR 27 MILES NORTH OF LARAMIE...MOVING NORTHEAST AT 20 MPH. THIS THUNDERSTORM WAS CAPABLE OF PRODUCING BRIEF TORRENTIAL RAINFALL WITH RAINFALL RATES OF 2 TO 4 INCHES PER HOUR POSSIBLE. THE TORRENTIAL RAINFALL WILL MOST LIKELY NOT LAST MORE THAN 30 MINUTES AND PRODUCE TOTAL RAINFALL AMOUNTS OF 1 TO 2 INCHES. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... MAINLY RURAL AREAS OF EASTERN ALBANY COUNTY. THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. 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 4197 10553 4190 10531 4159 10560 4167 10574 TIME...MOT...LOC 1910Z 212DEG 16KT 4172 10558 COX
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 232 PM MDT FRI JUL 12 2013 WYZ109-110-113-122115- CENTRAL CARBON COUNTY WY-NORTH SNOWY RANGE FOOTHILLS WY-UPPER NORTH PLATTE RIVER BASIN WY- 232 PM MDT FRI JUL 12 2013 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL CARBON COUNTY UNTIL 315 PM MDT... AT 227 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10 MILES SOUTHEAST OF SINCLAIR...OR 15 MILES EAST OF RAWLINS...MOVING NORTHEAST AT 25 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... HANNA... THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 224 AND 240. 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 4208 10678 4190 10647 4161 10691 4173 10709 TIME...MOT...LOC 2032Z 221DEG 20KT 4174 10692 MSW
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 304 PM MDT FRI JUL 12 2013 WYZ106>108-118-122145- CENTRAL LARAMIE COUNTY WY-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY WY-EAST PLATTE COUNTY WY-GOSHEN COUNTY WY- 304 PM MDT FRI JUL 12 2013 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN PLATTE...EXTREME NORTHERN LARAMIE AND CENTRAL GOSHEN COUNTIES UNTIL 345 PM MDT... AT 302 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 6 MILES SOUTHEAST OF CHUGWATER...OR 26 MILES SOUTHEAST OF WHEATLAND...MOVING NORTHEAST AT 25 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... VETERAN... YODER... THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 49 AND 58. 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 4206 10444 4188 10422 4159 10473 4172 10489 TIME...MOT...LOC 2104Z 228DEG 21KT 4172 10471 MSW
The Cheyenne radar (KCYS), 66 km away, was scanning. The volume nearest the first event began at 21:45 UTC.
1 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds snapped several power poles near Highway 313 about 15 miles east of Chugwater.
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, July 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: 453449.