Mid-level moisture over Utah helped produce increasingly organized convection beginning on July 10th. However, with the boundary layer remaining somewhat dry, these thunderstorms primarily produced strong, gusty winds.
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 SLC wrote it up.
Mid-level moisture over Utah helped produce increasingly organized convection beginning on July 10th. However, with the boundary layer remaining somewhat dry, these thunderstorms primarily produced strong, gusty winds.
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 Jul 10, 8:14 AM MST, 2 hours 31 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 914 AM MDT TUE JUL 10 2012 .SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL CENTER OVER THE REGION THROUGH MIDWEEK. THIS HIGH PRESSURE WILL SLOWLY SHIFT EAST LATE IN THE WEEK...ALLOWING DEEPER MOISTURE TO RETURN BY THE WEEKEND. && .DISCUSSION...THE MEAN LAYER RIDGE REMAINS CENTERED OVER SOUTHWEST UTAH THIS MORNING WITH A HOT AIRMASS IN PLACE. ENOUGH MOISTURE REMAINS IN PLACE FOR ISOLATED TERRAIN BASED CONVECTION POSSIBLY A LITTLE MORE NUMEROUS SOUTH. CELL DRIFT WILL CONTINUE TO BE MAINLY TOWARDS THE SOUTH AND SOUTHWEST ALTHO STORMS WILL BE A LITTLE SLOWER TODAY CLOSER TO THE CENTER OF THE HIGH. THE THREAT OF HEAVY RAIN AND ANY FLASH FLOODING IS LOW DUE TO THE LIMITED MOISTURE BUT IF A LONE STORM DOES BECOME BETTER DEVELOPED...THE SLOW MOVEMENT COULD RESULT IN SOME DECENT RAINFALL AMOUNTS IN SMALL AREAS. THERE IS A FIELD OF ALTOCUMULUS OVER NWRN UT INDICATING THE PRESENCE OF MID LEVEL MOISTURE. THIS COULD PRODUCE A FEW HIGH BASED STORMS ACROSS THE NW DESERTS LATER TODAY ONCE THE DAYTIME THERMAL UPDRAFTS REACH THIS LAYER AND HERE CELL DRIFT WOULD BE MORE TOWARDS THE NORTHEAST. THE HIGH IS FORECAST TO FLATTEN A BIT WED WITH A THREAT OF DRIER HIGH BASED STORMS PERSISTING ACROSS THE NORTH ALONG WITH THE USUAL DIURNAL MTN CONVECTION. THE HIGH STARTS TO EXPAND NORTH THU WITH A SLIGHT INCREASE IN MOISTURE ACROSS THE SRN 1/2 OF THE CWA AND IT IS STILL EXPECTED TO SHIFT EAST FRI WITH THE RESULTING SOUTHERLY FLOW ALLOWING DEEP MOISTURE TO MOVE INTO THE STATE. UPDATED TO INCREASE SKY COVER A BIT AND ADD LOW POPS TO THE NW. NO ADDITIONAL UPDATES PLANNED. && .AVIATION...SOUTHERLY WINDS AT THE SLC TERMINAL WILL SWITCH TO NORTHWESTERLY ABOUT 19-20Z TODAY. VFR CONDITIONS WILL PREVAIL WITH MOSTLY CLEAR SKIES. THUNDERSTORMS ARE NOT EXPECTED TO DIRECTLY IMPACT THE SLC TERMINAL TODAY THROUGH TONIGHT. && .FIRE WEATHER...THE HIGH PRESSURE OVER THE REGION WILL PREVAIL THROUGH THURSDAY WITH A CONTINUED WARMING TREND AND AN EXPANDING AREA OF VERY LOW RELATIVE HUMIDITY VALUES. WINDS WILL BE LIGHT AND GENERALLY TERRAIN DRIVEN EXCEPT IN AND AROUND ANY THUNDERSTORMS WHERE GUSTY AND ERRATIC WINDS WILL OCCUR. ONLY ISOLATED BRIEF HEAVY RAIN IS EXPECTED FROM STORMS THROUGH THURSDAY. AFTER THURSDAY...DEEP MOISTURE WILL SPREAD NORTH ACROSS THE REGION...INCREASING THE THREAT OF SHOWERS AND THUNDERSTORMS AND HEAVIER WETTING RAINS. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && WILENSKY/HOSENFELD 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 343 AM MDT TUE JUL 10 2012 UTZ001>016-019>021-517-518-WYZ021-111100- 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- 343 AM MDT TUE JUL 10 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT STRONG HIGH PRESSURE WILL BRING A CONTINUED WARMING TREND TODAY...WITH MANY VALLEY LOCATIONS INCLUDING THE WASATCH FRONT EXPECTED TO OR EXCEED THE CENTURY MARK...WHILE THE DIXIE REGION PUSHES 110. LINGERING MOISTURE WILL ALLOW FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS PRIMARILY ACROSS THE HIGHER TERRAIN...BUT SPREADING INTO ADJACENT VALLEY LOCATIONS AT TIMES. THESE STORMS WILL BE MOST NUMEROUS ACROSS SOUTHERN UTAH. LOCAL HEAVY RAINFALL IS POSSIBLE WHICH COULD RESULT IN ISOLATED FLASH FLOODING IN PRONE AREAS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE HEAT WILL CONTINUE THROUGH THURSDAY WITH HIGH TEMPERATURES TOPPING OUT NEAR OR ABOVE 100 DEGREES ACROSS MOST VALLEY LOCATIONS. LINGERING MOISTURE THROUGHOUT MID-WEEK WILL MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND ISOLATED FLASH FLOODING...IN ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING. THE THREAT FOR THUNDERSTORMS WILL INCREASE LATE IN THE WEEK THROUGH THE UPCOMING WEEKEND AS MOISTURE INCREASES ACROSS THE REGION...BRINGING A GREATER CHANCE FOR FLASH FLOODING. .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 TRAVEL IMPACTS VISIT... HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
958 AM MDT TUE JUL 10 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0735 PM FLASH FLOOD 10 E BIG WATER 37.09N 111.49W
07/07/2012 KANE UT PUBLIC
FLASH FLOOD IN CROSBY CANYON IN GLEN CANYON NATIONAL
RECRATION AREA. FLASH FLOOD CROSSED THE SMOKEY MOUNTAIN
ROAD.
&&
HOSENFELDThe Salt Lake City radar (KMTX), 47 km away, was scanning. The volume nearest the first event began at 17:44 UTC.
4 thunderstorm wind. Local standard time, as filed.
A maximum wind gust of 63 mph was measured at the Utah Test and Training Range, and windows were damaged on 7 of the cars in the parking lot.
The Ogden Peak sensor recorded a maximum wind gust of 77 mph.
The Target S sensor in the Dugway Proving Ground mesonet recorded a wind gust of 64 mph.
A strong thunderstorm moved through the Tooele Valley, producing severe winds. Recorded wind gusts included 65 mph at South Mountain and the Great Salt Lake Marina, 62 mph at the Lake Point at I-80 sensor, and 59 mph at the Tooele City and Stockton Bar sensors.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2012Every state in 2012This day in weather historyWarnings in Utah, July 2012
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: 403665, 403668, 403673, 403681.