The air mass over southern Utah remained moist on July 24 and 25, and the resultant thunderstorms caused some flash floods.
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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.
The air mass over southern Utah remained moist on July 24 and 25, and the resultant thunderstorms caused some flash floods.
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 24, 3:22 PM MST, 8 minutes earlier.
Area Forecast Discussion National Weather Service Salt Lake City UT 422 PM MDT Tue Jul 24 2018 .SYNOPSIS...A ridge of high pressure centered just south of the Four Corners area will move slowly move westward through the period. This will effectively shut off the monsoonal flow as the week progresses, bring drier conditions. Hot temperatures will continue. && .SHORT TERM (Through 18Z Friday)...A large upper level ridge is centered over Arizona this afternoon, which is producing hot temperatures over a wide swath of the western CONUS, including Utah and southwest Wyoming. The hottest temperatures in Utah are being observed near the Arizona border, with the St. George Airport sitting at 108 degrees as of 22Z. The Excessive Heat Warnings for Dixie and Lake Powell look to be in good shape, and remain in place through Thursday. Scattered showers and thunderstorms have once again formed over the higher terrain, especially in the southern half of Utah. A couple of places have received enough rainfall for flash flooding concerns, including the Brian Head burn scar. Isolated heavy rainers will continue to be possible through the evening. Further north, storms have formed as expected in eastern Nevada and southern Idaho, with a couple of these storms barely sneaking into northwest Utah. This activity will continue into the evening and perhaps overnight hours. The idea of one or two of these storms reaching the Wasatch Front tonight isn't out of the question, but given the pessimism of various high resolution models, have left mentionable POPs out of the urban corridor for now. As the upper ridge circulation continues to shift slowly westward, moving over southern California for Wednesday into Thursday, west- northwesterly flow will increase over the Great Basin, pushing a drier airmass into Utah through the rest of the work week. This should generally decrease (though not eliminate) the coverage of diurnal thunderstorms over the next few days. Temperatures are generally expected to peak on Wednesday, then decrease subtly through the end of the week, slowly dropping temperatures from "very hot" to just "hot." .LONG TERM (After 18Z Friday)...The ridge of high pressure will remain anchored just to the southwest of the forecast area through Monday, amplifying a bit more. This pattern will continue to promote a dry northwest flow with precipitable water values continuing to decline through the period. Will opt for some mention for showers and thunderstorms across primarily higher terrain of southern Utah for Friday and Saturday. With continue with dry weather for Sunday and Monday. Hot temperatures will continue. Global models prog the high pressure ridge to shift a bit eastward on Tuesday, setting up a trajectory for moisture return. && .AVIATION...VFR conditions will prevail through the valid TAF period. There is a 10 percent chance that an outflow across extreme northern Utah, that originated from thunderstorms over southern Idaho, will enhance a northwest lake breeze early this evening. The northwest lake breeze will switch to a southeast drainage wind around 03Z. && .FIRE WEATHER...Scattered thunderstorms have again formed on the higher terrain of Utah today, primarily in central and southern Utah. These storms should dissipate in the evening, except perhaps in far western Utah with storms coming out of Nevada. Coverage of thunderstorms and relative humidity values should both generally decrease through the week, as drier air pushes into the state. Otherwise, hot temperatures will prevail through the week, with primarily light winds away from thunderstorms. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Excessive Heat Warning until 10 PM MDT Thursday for UTZ019-021. WY...None. && SHORT TERM...Schoening LONG TERM...Barjenbruch AVIATION...Barjenbruch FIRE WEATHER...Schoening For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php
Hazardous Weather Outlook National Weather Service Salt Lake City UT 554 AM MDT Tue Jul 24 2018 UTZ001>016-019>021-517-518-WYZ021-251300- 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- 554 AM MDT Tue Jul 24 2018 This Hazardous Weather Outlook is for the western two thirds of Utah and southwest Wyoming. .DAY ONE...Today and Tonight Isolated to scattered showers and thunderstorms will remain possible. Gusty winds, small hail, and brief heavy rain will be possible with the stronger storms. Temperatures will continue to trend warmer across much of the area today which is expected to increase the threat of heat-related illnesses, especially across Utah's Dixie and the Lake Powell area. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Temperatures will remain elevated through most the week. Consecutive days of warm temperatures during both the daytime and overnight hours will continue to lead to an increased threat of heat-related illnesses, especially across Utah's Dixie and the Lake Powell area through late week. .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 For information on potential road travel impacts visit... http://www.udottraffic.utah.gov/roadweatherforecast.aspx
The Cedar City radar (KICX), 120 km away, was scanning. The volume nearest the first event began at 22:28 UTC.
2 flash flood. Local standard time, as filed.
Heavy rain produced a flash flood in Alvey Wash.
Heavy rain caused a flash flood along Sulphur Creek in Capitol Reef National Park.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2018Every state in 2018This day in weather historyWarnings in Utah, July 2018
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: 771784, 771786.