Showers and thunderstorms again developed across Utah on August 11, and a severe wind gust was recorded from one of these storms.
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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 SLC wrote it up.
Showers and thunderstorms again developed across Utah on August 11, and a severe wind gust was recorded from one of these storms.
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 Salt Lake City, UT wrote its last area forecast discussion before the first event at Aug 11, 8:28 AM MST, 6 hours 7 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 928 AM MDT TUE AUG 11 2015 .SYNOPSIS...MONSOONAL MOISTURE WILL INCREASE FROM SOUTH TO NORTH ACROSS THE REGION TODAY...AND REMAIN IN PLACE THROUGH MOST OF THE WEEK. && .DISCUSSION...DEEP LAYER SOUTHERLY FLOW PREVAILS ACROSS THE GREAT BASIN THIS MORNING...SANDWICHED BETWEEN AN UPPER RIDGE CENTERED ACROSS THE SOUTHERN PLAINS...AND AN UPPER LOW SPINNING JUST OFF THE PACIFIC NORTHWEST COAST. THIS FLOW IS ADVECTING DEEP MOISTURE NORTHWARD ACROSS THE FORECAST AREA...WHERE PW VALUES ARE IN EXCESS OF 1 INCH AND SURFACE DEW POINT VALUES IN THE 50S ACROSS MUCH OF SOUTHERN UT...WHILE OVER THE NORTH PW VALUES ARE JUST SHY OF 1 INCH AND DEW POINTS ARE GENERALLY IN THE MID TO UPPER 40S. MORNING WATER VAPOR SHOWS A WEAK SHORTWAVE EMBEDDED WITHIN THIS SOUTHERLY FLOW MOVING NORTHWARD ACROSS EAST CENTRAL UT...WHILE FURTHER SOUTH A LESS DISCERNIBLE FEATURE IS HELPING TO MAINTAIN SHOWERS AND THUNDERSTORMS ACROSS NORTHERN AZ. FAIRLY EXTENSIVE CLOUD COVER AND MODEST MID LEVEL LAPSE RATES ACROSS SOUTHERN UT AND NORTHERN AZ WILL LIKELY LIMIT THE DEGREE OF INSTABILITY THIS AFTERNOON. THE MOST LIKELY AREAS FOR DEEP CONVECTION WOULD SEEM TO BE ALONG THE NORTHERN AND WESTERN PERIPHERY OF THIS CLOUD SHIELD ACROSS CENTRAL UT...EVENTUALLY SPREADING INTO PORTIONS OF NORTHERN UT LATER THIS AFTERNOON INTO THIS EVENING. HOWEVER ANY BREAKS ACROSS SOUTHERN UT WOULD SEEM TO SUPPORT THE POTENTIAL FOR HEAVY RAINFALL GIVEN NARROW VERTICAL CAPE PROFILES...DEEP WARM CLOUD LAYER AND A WEAK UPSLOPE COMPONENT TO THE FLOW. 00Z CAMS MODELS AND RECENT HRRR RUNS DEPICT A FAIR AMOUNT OF UNCERTAINTY WITH RESPECT TO JUST HOW WIDESPREAD AND STRONG CONVECTION WILL BE THIS AFTERNOON...AND GIVEN THIS UNCERTAINTY COUPLED WITH EXTENSIVE CLOUD COVER HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH...INSTEAD OPTING TO MAINTAIN HEAVY RAIN WORDING IN THE FORECAST AND MODERATE FLASH FLOOD POTENTIAL. LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED WEDNESDAY AS THE AIRMASS REMAINS QUITE MOIST ACROSS THE REGION. BY THURSDAY SOMEWHAT DRIER AIR ALOFT IS FORECAST TO SPREAD ACROSS THE FORECAST AREA...HOWEVER WITH AMPLE BOUNDARY LAYER MOISTURE REMAINING IN PLACE THIS COULD WELL YIELD A MORE FAVORABLE SETUP FOR DEEP CONVECTION GIVEN AN INCREASE IN SURFACE HEATING. AT THIS POINT HAVE HELD OFF ON ANY UPDATES BUT WILL MONITOR RADAR SATELLITE TRENDS AND ADJUST POPS/CLOUD COVER IF NECESSARY. && .AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN SOUTHERLY THROUGH THE TAF PERIOD WITH A 20 PERCENT CHANCE OF SWITCHING TO THE NORTHWEST THIS AFTERNOON BETWEEN 20-23Z. SHOWERS AND THUNDERSTORMS WILL INCREASE ACROSS NORTHERN UTAH THIS AFTERNOON...WITH A 40 PERCENT CHANCE THAT THE TERMINAL WILL BE IMPACTED BY GUSTY OUTFLOW WINDS...CLOUD-TO-GROUND LIGHTNING...OR BRIEF MVFR CONDITIONS UNDER HEAVIER SHOWERS AFTER 22Z. && .FIRE WEATHER...A SURGE OF MONSOONAL MOISTURE WILL BRING SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL THROUGH AT LEAST WEDNESDAY. WITH THIS MOISTURE SURGE WILL ALSO COME HIGHER DAYTIME RH VALUES WITH EXCELLENT OVERNIGHT RECOVERY. SOME SLIGHT DRYING IS EXPECTED FOR THE LATTER PORTION OF THE WEEK...HOWEVER THE THREAT FOR SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING WETTING RAINS WILL REMAIN INTO THE UPCOMING WEEKEND. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && SEAMAN/VERZELLA FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE) FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION VISIT... HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SALT LAKE CITY UT 559 AM MDT TUE AUG 11 2015 UTZ001>016-019>021-517-518-WYZ021-121200- CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT- SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT- GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS- WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80- WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS- WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL- SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH- UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH- GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS- SOUTHERN MOUNTAINS-SOUTHWEST WYOMING- 559 AM MDT TUE AUG 11 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT MOISTURE WILL CONTINUE TO INCREASE ACROSS THE OUTLOOK AREA FROM THE SOUTH TODAY WITH SHOWERS AND THUNDERSTORMS BECOMING MORE NUMEROUS. LOCAL HEAVY RAIN IS POSSIBLE ALONG WITH THE THREAT OF ISOLATED FLASH FLOODING. THE SHOWERS AND THUNDERSTORMS WILL BECOME MORE ISOLATED TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE AGAIN WEDNESDAY ACROSS PRETTY MUCH THE ENTIRE OUTLOOK AREA. THESE STORMS WILL ONCE AGAIN BRING A THREAT OF HEAVY RAIN AND A HEIGHTENED POTENTIAL FOR FLASH FLOODING. A SLOW DRYING TREND IS EXPECTED TO START ON THURSDAY AND WILL CONTINUE INTO THE WEEKEND WITH STORMS BECOMING MORE ISOLATED AND LESS LIKELY TO PRODUCE HEAVY RAIN. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY/ (ALL LOWER CASE) FOR INFORMATION ON POTENTIAL ROAD TRAVEL IMPACTS VISIT... HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SALT LAKE CITY UT 244 PM MDT TUE AUG 11 2015 UTZ005-112145- GREAT SALT LAKE DESERT AND MOUNTAINS UT- 244 PM MDT TUE AUG 11 2015 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL TOOELE COUNTY UNTIL 345 PM MDT... AT 243 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 18 MILES SOUTHWEST OF KNOLLS...OR 25 MILES SOUTHEAST OF WENDOVER...MOVING NORTHEAST AT 30 MPH. ADDITIONAL STRONG THUNDERSTORMS ARE LOCATED THROUGH WESTERN TOOELE COUNTY. WINDS OF 40 TO 55 MPH WILL BE POSSIBLE. A WIND GUST TO 57 MPH WAS REPORTED WITH THESE STORMS. LOCATIONS IMPACTED INCLUDE... KNOLLS AND CLIVE AND INTERSTATE 80 FROM THE BONNEVILLE SALT FLATS TO WEST OF DELLE. PRECAUTIONARY/PREPAREDNESS ACTIONS... IF THREATENING WEATHER APPROACHES...TAKE SHELTER IN A STURDY BUILDING. && LAT...LON 3992 11336 4051 11395 4096 11332 4034 11261 TIME...MOT...LOC 2043Z 231DEG 24KT 4059 11358 CRK
The Salt Lake City radar (KMTX), 110 km away, was scanning. The volume nearest the first event began at 21:37 UTC.
1 thunderstorm wind. Local standard time, as filed.
A 59 mph wind gust was recorded at the Upper Cedar Mountain sensor in the Dugway Proving Ground mesonet.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2015Every state in 2015This day in weather historyWarnings in Utah, August 2015
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: 599448.