A moist air mass moved into Utah for the beginning of August, helping produce showers and thunderstorms across the state. Flash flooding was observed in both southern and northern Utah during this period.
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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.
A moist air mass moved into Utah for the beginning of August, helping produce showers and thunderstorms across the state. Flash flooding was observed in both southern and northern Utah during this period.
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 2, 9:12 PM MST, 1 hour 18 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 1012 PM MDT SUN AUG 2 2015 .SYNOPSIS...A WEAK UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY TRACK SOUTH TO NORTH ACROSS THE REGION TONIGHT THROUGH EARLY MONDAY. A DRIER SOUTHWESTERLY FLOW WILL FOLLOW FOR MIDWEEK. && .SHORT TERM (UNTIL 12Z WEDNESDAY)...ANIMATED WATER VAPOR IMAGERY BEGINNING TO SUGGEST THAT A CONSOLIDATED UPPER LOW IS FORMING ACROSS CENTRAL UTAH LATE THIS EVENING. THIS DEVELOPMENT FITS WITH THE MODEL GUIDANCE WHICH BRINGS THIS FEATURE FROM CENTRAL UTAH INTO NORTHERN UTAH LATER TONIGHT/EARLY MONDAY. DEEP LAYER MOISTURE AND SOLID DYNAMIC LIFT SHOULD BRING SOME PRECIP ACROSS THE NORTH THROUGH AT LEAST MONDAY MORNING. RESIDUAL MOISTURE TRAILING THE UPPER LOW WILL LIKELY FUEL DIURNAL CONVECTION ACROSS SOUTHERN AND CENTRAL UTAH MONDAY AFTERNOON AND EARLY EVENING. HIGH PRESSURE ALOFT WILL SETTLE INTO UTAH BY TUESDAY...THEN SHIFT OFF TO THE EAST MIDWEEK. A SIGNIFICANTLY DRIER SOUTHWEST FLOW ALOFT WILL FOLLOW THE PASSING RIDGE BEGINNING LATE TUESDAY. .PREVIOUS LONG TERM (AFTER 12Z WEDNESDAY)...THE SUBTROPICAL RIDGE AXIS CENTERED OVER THE AZ/NM BORDER SUBTLY SHIFTS EASTWARD ON WEDNESDAY AS A LOW AMPLITUDE TROUGH SNEAKS TOWARD NORTHERN UTAH...PROMOTING A RELATIVELY DRY SOUTHWESTERLY FLOW ALOFT. A WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW ACCOMPANIED BY INCREASING PWAT WILL PROVIDE AMPLE DYNAMICS TO ENCOURAGE AFTERNOON AND EVENING CONVECTION IN NORTHERN UTAH. THIS FEATURE ALSO COOLS DOWN 7H TEMPERATURES A FEW DEGREES... DELIVERING TEMPS ABOUT 5 DEGREES BELOW SEASONAL NORMS FOR THE NORTHERN HALF OF THE STATE. HAVE LOWERED APPROPRIATE THURSDAY MAX TEMPS A BIT TO REFLECT THIS. LINGERING INSTABILITY OVER THE UINTAS MAY BE THE ONLY CHANCE FOR A DOLLOP OF CONVECTIVE ACTIVITY ON THURSDAY AFTERNOON. FRIDAY TEMPS WARM RAPIDLY AHEAD OF AN ENCROACHING AND DEEPENING LOW PRESSURE SYSTEM SWINGING INTO CALIFORNIA. MODELS DIVERGE AT THIS POINT ON TIMING AND IMPACT OF THIS LOW AS IT PROGRESSES TOWARD UTAH. THE GFS HAS REMAINED STAUNCH IN DELIVERING PRECIP INTO THE CWA BY FRIDAY...WHILE THE ECMWF REMAINS SLOWER...LESS MOIST AND LESS EXTENSIVE IN COVERAGE. IN EITHER CASE...EXPECTING MIDLEVEL SOUTHWEST WINDS TO RAMP UP BY FRIDAY EVENING ACROSS MUCH OF THE STATE. HAVE INTRODUCED POPS IN SOUTHERN UTAH BY FRIDAY 18Z AND EXTENDED THEM A BIT FURTHER NORTH ON SATURDAY TO GENTLY NUDGE TOWARD GFS SOLUTION. DRIER AIR RAPIDLY REPLACES THE EXITING SYSTEM SATURDAY INTO SUNDAY...BRINGING A ZONAL UPPER LEVEL FLOW AND QUIET END TO THE WEEKEND. && .AVIATION...SURFACE HIGH PRESSURE OVER CENTRAL UTAH AND A SOUTHEAST FLOW ALOFT WILL MAINTAIN SOUTH-SOUTHEAST WINDS THE KSLC TERMINAL THROUGH THE NIGHT. AN UPPER LOW MOVING NORTH ACROSS THE STATE WILL BRING SHOWERS BACK INTO THE TERMINAL AREA AFTER 06Z. THE BEST CHANCE FOR RAIN WILL EXIST BETWEEN 08Z AND 15Z. VFR CONDITIONS WILL PREVAIL...THOUGH CEILINGS COULD DIP DOWN TO AROUND 7000 TO 8000 FEET IN PRECIP. && .FIRE WEATHER...A WEATHER DISTURBANCE IS TRACKING ALONG THE UTAH/NEVADA BORDER THIS AFTERNOON...ALLOWING DEEP MOISTURE TO SPREAD INTO THE SOUTHERN TWO-THIRDS OF UTAH. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN THIS MOIST AND UNSTABLE AIRMASS...AND THE FOCUS OF CONVECTION WILL SHIFT NORTHWARD THIS EVENING AS THE DISTURBANCE CONTINUES NORTHWARD...THEN CUTS OVER NORTHERN UTAH TONIGHT AND TOMORROW. THERE IS A CHANCE OF WETTING RAIN WITH ANY OF THESE SHOWERS AND THUNDERSTORMS. WITH THE NORTHWARD MOVEMENT OF THE DISTURBANCE...DRIER AIR WILL MOVE BACK INTO THE DISTRICT FROM THE SOUTH TONIGHT THROUGH TUESDAY. UNDER THE INFLUENCE OF THE WAVE...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER NORTHERN UTAH TOMORROW BEFORE COVERAGE DECREASE TUESDAY UNDER WEAK HIGH PRESSURE. SOUTHERLY WINDS WILL BEGIN TO INCREASE TUESDAY AND WEDNESDAY AS ANOTHER TROUGH BEGINS TO APPROACH THE AREA. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && SHORT TERM/AVIATION...CONGER LONG TERM...VERZELLA FIRE WEATHER...TRAPHAGAN 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)
The Cedar City radar (KICX), 125 km away, was scanning. The volume nearest the first event began at 05:28 UTC.
2 flash flood. Local standard time, as filed.
A large flash flood was reported in the Wahweap drainage, north of Big Water.
Heavy rain over northern Davis County caused widespread street and parking lot flooding, particularly in Farmington and Layton. In addition, several homes in Fruit Heights experienced basement flooding.
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: 600648, 600649.