A shortwave trough brushed across northern Utah, resulting in enough support for the development of scattered high-based thunderstorms. A few of these thunderstorms produced instances of severe level wind gusts.
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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 shortwave trough brushed across northern Utah, resulting in enough support for the development of scattered high-based thunderstorms. A few of these thunderstorms produced instances of severe level wind gusts.
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 Sep 3, 1:51 PM MST, 39 minutes earlier.
Area Forecast Discussion National Weather Service Salt Lake City UT 251 PM MDT Tue Sep 3 2024 .SYNOPSIS...One last round of thunderstorms with the potential for strong, gusty microburst winds this afternoon and evening, especially north of I-70. A weak cold front will cross the state tonight into Wednesday morning, bringing a cooler air mass along with stable conditions and likely increased smoke. && .SHORT TERM...(Through 12Z Thursday)...Water vapor satellite imagery this afternoon shows a broad circulation center over central Idaho with a shortwave trough at its base over northern Nevada and tracking towards the northern portions of our forecast area. Surface radars are beginning to show a convective linear feature moving northeastward across the West Desert similar to what high- res models have been forecasting consistently since early this morning. This is in an environment of 0.7-0.8" PWAT per latest SPC mesoanalysis, or near normal for this time of year per satellite analysis tool. The aforementioned trough is providing around 40 kts of 0-6km shear, coupled with 500-1000 J/Kg surface- based CAPE (also per SPC mesoanalysis). Inverted-V soundings indicative of microburst potential are presented in both the morning SLC sounding and model soundings. Nearly of the high-res guidance continues to highlight a threat of microburst winds for the Wasatch Front, as early as 3pm to as late as 6pm, with a most likely window between 4 and 5 pm. HREF probabilities of gusts exceeding 50mph in a 25km radius exceed 70% through this time, especially on the west side of Utah Lake and in the Rush/Tooele valleys. Storms will trend wetter as the event continues, with rain likely to reach the ground in heavier cores (but not likely to exceed 0.1"). HREF members also consistently indicate additional rounds of convection into the evening after the windy convective line pushes through. Thus, a Red Flag Warning continues through this evening. By this evening, the trough mentioned earlier will set up cold air advection, with a much drier air mass moving in at the same time. This will cut off the convection from northwest to southeast overnight. Unfortunately, the cooler/drier air mass upstream of our area happens to contain a lot of smoke from fires in Idaho and Oregon, as easily seen currently in GeoColor satellite imagery. The HRRR model is forecasting that this smoke will be advected into northern Utah and southwest Wyoming through the day tomorrow and into tomorrow night, with haze eventually reaching as far south as I-70. Just how thick the smoke will be over our area and resultant air quality implications remains to be seen. It is worth noting that there were a number of new starts reported in the Boise WFO's area, which could add to the pooled smoke. .LONG TERM (After 12Z Thursday), Issued 409 AM MDT... An upper-level ridge will build over the Great Basin late in the work week, producing sunny skies and temperatures just above normal. However, this dry period will be short-lived as the ridge continues to nudge eastward, allowing monsoonal moisture to once again push into southern Utah on Saturday. Precipitation chances on Saturday afternoon will be limited to southwestern Utah, though moisture will continue to overspread the state heading later into the weekend...bringing those chances across all of Utah and southwest Wyoming. As is typical with the onset of monsoonal moisture, dry microbursts will be a threat at first, though increasing moisture could produce a flash flood threat on Sunday or Monday as PWATs increase to around 0.9" across southern Utah. Moisture is likely to stick around heading into the work week. Model guidance still suggests the development of a strong longwave trough over the northeastern Pacific, though it is unclear if/when it affects our forecast area. Currently, ~50% of ensemble members suggest the trough makes it to our doorstep by late Wednesday...but even with that lies great uncertainty in the amplitude of the trough itself. && .AVIATION...KSLC...Occasional thunderstorms with gusty and erratic outflow winds will impact the terminal during the 23-03Z timeframe. Outflow winds will likely exceed 26 kts at times. There is a 30% chance for VIS to fall into the MVFR category during this timeframe. Winds will become southeast through the late evening and overnight hours, with a switch to the northwest during the 10-12z timeframe. There is a 30% chance VIS falls into the MVFR range after 18z Wednesday due to smoke from upstream wildfires moving into the area. .REST OF UTAH AND SOUTHWEST WYOMING...Occasional showers and thunderstorms with gusty outflow winds in excess of 30kts will impact TAF sites south of I-80 through 03Z. The strongest storms will impact KPVU and KHCR with winds in excess of 40 kts possible between 23z and 02z. Shower and thunderstorm coverage will become more isolated across the region after 03Z with winds becoming diurnally driven. A weak cold front will turn winds to the northwest across northern Utah before 12Z Wednesday, with a 30-40% chance VIS falls into the MVFR range by afternoon along/north of I-80 due to smoke from upstream wildfires spreading into the area. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Red Flag Warning until midnight MDT tonight for UTZ478-479. WY...None. && Van Cleave/Seaman/Kruse/Cunningham For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity
Special Weather Statement
National Weather Service Salt Lake City UT
1256 PM MDT Tue Sep 3 2024
UTZ117-119-120-126-031945-
Sevier Valley UT-Castle Country UT-Upper Sevier River Valleys UT-
Central Mountains UT-
1256 PM MDT Tue Sep 3 2024
...A strong thunderstorm will impact portions of eastern Sevier
County through 145 PM MDT...
At 1255 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles east of Annabella, or 11 miles east of Richfield, moving
northeast at 20 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Richfield, Salina, Aurora, Redmond, Glenwood, Sigurd, and Fremont
Junction.
This includes the following highways...
Interstate 70 between mile markers 39 and 92.
US Route 50 between mile markers 156 and 158.
US Route 89 between mile markers 226 and 231.
Utah Route 10 between mile markers 0 and 1.
Utah Route 24 between mile markers 16 and 27.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3876 11129 3858 11173 3878 11213 3904 11181
3904 11179
TIME...MOT...LOC 1855Z 210DEG 15KT 3876 11189
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
NDSpecial Weather Statement
National Weather Service Salt Lake City UT
247 PM MDT Tue Sep 3 2024
UTZ101-102-106-111-115>117-032130-
Western Millard and Juab Counties UT-Utah Valley UT-
Central Mountains UT-Tooele and Rush Valleys UT-
Great Salt Lake Desert and Mountains UT-
Eastern Juab/Millard Counties UT-Wasatch Mountains South of I-80 UT-
247 PM MDT Tue Sep 3 2024
...A line of strong thunderstorms will impact portions of
northeastern Millard, eastern Juab, southwestern Utah and
southeastern Tooele Counties through 330 PM MDT...
At 246 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 10 miles southeast of Dugway Proving Ground
Test Range to 23 miles southwest of Vernon to near Delta. Movement
was northeast at 30 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Nephi, Delta, Dugway English Village, Santaquin, Rocky Ridge, Vernon,
Tooele Army Depot South, Dugway Proving Ground Test Range, Elberta,
West Mountain, Utah Lake, Mona, Genola, Goshen, Levan, Eureka, Oak
City, Rush Valley, Leamington, and Lynndyl.
This storm will be capable of producing strong gusty winds on Utah
Lake. This will lead to a sudden increase in waves and very choppy
waters which will result in hazardous boating conditions. Boaters are
urged to seek safe harbor if possible.
This includes the following highways...
Interstate 15 between mile markers 205 and 243.
US Route 6 between mile markers 85 and 159.
US Route 50 between mile markers 90 and 93.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4042 11247 4005 11180 3952 11174 3931 11264
3977 11269 4012 11341
TIME...MOT...LOC 2046Z 247DEG 43KT 4004 11316 3979 11265 3940 11261
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
NDSpecial Weather Statement
National Weather Service Salt Lake City UT
327 PM MDT Tue Sep 3 2024
UTZ101-102-106-111-115>118-032215-
Sanpete Valley UT-Western Millard and Juab Counties UT-
Utah Valley UT-Central Mountains UT-Tooele and Rush Valleys UT-
Great Salt Lake Desert and Mountains UT-
Eastern Juab/Millard Counties UT-Wasatch Mountains South of I-80 UT-
327 PM MDT Tue Sep 3 2024
...A line of strong thunderstorms will impact portions of northern
Sanpete, northeastern Millard, northeastern Juab, southern Salt
Lake, southwestern Utah and southeastern Tooele Counties through 415
PM MDT...
At 326 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles northwest of Vernon to 16 miles west of
Elberta to 23 miles west of Nephi. Movement was northeast at 30 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Provo, Payson, Nephi, Dugway English Village, Spanish Fork,
Springville, Eagle Mountain, Santaquin, Salem, Elk Ridge, Woodland
Hills, Rocky Ridge, Cedar Fort, Vernon, Ophir, Camp Williams,
Palmyra, Lake Shore, Tooele Army Depot South, and Benjamin.
This storm will be capable of producing strong gusty winds on Utah
Lake. This will lead to a sudden increase in waves and very choppy
waters which will result in hazardous boating conditions. Boaters are
urged to seek safe harbor if possible.
This includes the following highways...
Interstate 15 between mile markers 216 and 257.
US Route 6 between mile markers 109 and 160.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4047 11210 4020 11165 3968 11163 3949 11234
3992 11237 4020 11286
TIME...MOT...LOC 2126Z 241DEG 28KT 4015 11258 3997 11228 3960 11225
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
NDThe Salt Lake City radar (KMTX), 126 km away, was scanning. The volume nearest the first event began at 21:32 UTC.
3 thunderstorm wind. Local standard time, as filed.
The VERNON HILL mesonet station recorded a wind gust of 67 mph as a result of outflow winds associated with a nearby cluster of showers and thunderstorms moving through the area.
The I-80 at MP 71 East Delle mesonet station recorded a wind gust of 63 mph as a result of outflow winds associated with a nearby cluster of showers and thunderstorms moving through the area.
The I-80 at MP 68 West Delle mesonet station recorded a wind gust of 62 mph as a result of outflow winds associated with a nearby cluster of showers and thunderstorms moving through the area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2024Every state in 2024This day in weather historyWarnings in Utah, September 2024
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: 1207029, 1207031, 1207033.