Alert archive / Utah / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 71, NWS Salt Lake City, UT
NWS Salt Lake City, UT issued this severe thunderstorm warning at Aug 22, 2026, 5:14 PM MDT for Box Elder County, Tooele County, Utah. It was in force for 27 min. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 22, 2026, 5:14 PM MDT (23:14 UTC)
- Expired
- Aug 22, 2026, 5:41 PM MDT
- In force
- 27 min
- Issued by
- NWS Salt Lake City, UT
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Hail
- 1.0 in
- Wind
- 70.0 mph
Counties Box Elder County, UT, Tooele County, UT
The radar
The Salt Lake City radar (KMTX), 96 km from the middle of the area, began a volume at 23:15 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 22, 5:15 PM MDT | TSTM WND GST 62 | 10 W Knolls, UT | UDOT Interstate 80. |
| Aug 22, 5:20 PM MDT | TSTM WND GST 64 | 10 W Knolls, UT | UDOT Interstate 80. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this severe thunderstorm warning; the first came 1 minutes after it went out.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Salt Lake City I, UT (KSLC), launched 12:00Z, 11.2 hours before the alert went out and 127 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 18 J/kg
- Mixed-layer CIN
- -294 J/kg
- Mixed-layer LCL
- 1899 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 37 m²/s²
- 0-3 km storm-relative helicity
- 97 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
986
WUUS55 KSLC 222314
SVRSLC
UTC003-045-230000-
/O.NEW.KSLC.SV.W.0071.260822T2314Z-260823T0000Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
514 PM MDT Sat Aug 22 2026
The National Weather Service in Salt Lake City has issued a
* Severe Thunderstorm Warning for...
Southwestern Box Elder County in northern Utah...
North central Tooele County in northern Utah...
* Until 600 PM MDT.
* At 512 PM MDT, a severe thunderstorm was located 10 miles west of
Knolls, or 29 miles east of Wendover, moving northeast at 25 mph.
HAZARD...70 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect considerable
tree damage. Wind damage is also likely to mobile homes,
roofs, and outbuildings.
* Locations impacted include...
Utah Test and Training Range North.
This includes Interstate 80 in Utah between mile markers 26 and 36.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4067 11349 4077 11361 4106 11338 4084 11308
TIME...MOT...LOC 2312Z 225DEG 20KT 4076 11347
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH
$$
JCW2 follow-up statements
968
WWUS55 KSLC 222328
SVSSLC
Severe Weather Statement
National Weather Service Salt Lake City UT
528 PM MDT Sat Aug 22 2026
UTC003-045-230000-
/O.CON.KSLC.SV.W.0071.000000T0000Z-260823T0000Z/
Box Elder UT-Tooele UT-
528 PM MDT Sat Aug 22 2026
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM MDT
FOR SOUTHWESTERN BOX ELDER AND NORTH CENTRAL TOOELE COUNTIES...
At 528 PM MDT, a severe thunderstorm was located 7 miles northwest of
Knolls, or 34 miles east of Wendover, moving east at 25 mph.
HAZARD...70 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect considerable
tree damage. Wind damage is also likely to mobile homes,
roofs, and outbuildings.
Locations impacted include...
Utah Test and Training Range North.
This includes Interstate 80 in Utah between mile markers 31 and 32.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4072 11346 4081 11357 4106 11338 4084 11308
TIME...MOT...LOC 2328Z 270DEG 20KT 4080 11337
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH
$$
JCW660 WWUS55 KSLC 222341 SVSSLC Severe Weather Statement National Weather Service Salt Lake City UT 541 PM MDT Sat Aug 22 2026 UTC003-045-222351- /O.CAN.KSLC.SV.W.0071.000000T0000Z-260823T0000Z/ Box Elder UT-Tooele UT- 541 PM MDT Sat Aug 22 2026 ...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN BOX ELDER AND NORTH CENTRAL TOOELE COUNTIES IS CANCELLED... The storm which prompted the warning has weakened below severe limits, and no longer poses an immediate threat to life or property. Therefore, the warning has been cancelled. However gusty winds and heavy rain are still possible with this thunderstorm. LAT...LON 4072 11346 4081 11357 4106 11338 4084 11308 TIME...MOT...LOC 2339Z 225DEG 20KT 4085 11330 $$ JCW
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 22, 1:35 PM MDT, 3 hours 39 minutes earlier. Its key messages:
- There is a Marginal Risk (level 1/4) for excessive rainfall across most of the region through the weekend.
- There is a Marginal Risk (level 1/5) for severe thunderstorms across portions of northwestern Utah today. There is a 5-10% chance of wind gusts in excess of 58 mph in this area through the evening.
- A Slight Risk (level 2/5) for severe thunderstorms is outlooked for Sunday afternoon and evening across much of northern Utah. There is a 10% chance of wind gusts in excess of 70 mph with these thunderstorms Sunday afternoon and evening.
Area forecast discussion, Aug 22, 1:35 PM MDT, 3 hours 39 minutes before
Area Forecast Discussion National Weather Service Salt Lake City UT 135 PM MDT Sat Aug 22 2026 .KEY MESSAGES... - There is a Marginal Risk (level 1/4) for excessive rainfall across most of the region through the weekend. - There is a Marginal Risk (level 1/5) for severe thunderstorms across portions of northwestern Utah today. There is a 5-10% chance of wind gusts in excess of 58 mph in this area through the evening. - A Slight Risk (level 2/5) for severe thunderstorms is outlooked for Sunday afternoon and evening across much of northern Utah. There is a 10% chance of wind gusts in excess of 70 mph with these thunderstorms Sunday afternoon and evening. && .DISCUSSION...Increased moisture across the region will support thunderstorms capable of heavy rainfall rates. With relatively slow storm motions today, already seeing convection anchored on terrain training in locations and producing localized flooding of small streams and dry washes. Will need to continue to monitor central and southern Utah through the evening as rainfall rates in excess of 0.50-0.75 inches per hour have been observed. The most prone locations will be slot canyons, normally dry washes, slick rock areas, areas with poor drainage and of course the numerous recent burn scars across the region. Across northwestern Utah, CAMS suggest the threat of strong to severe microburst winds. One inhibiting factor will be the mid- morning to early afternoon convection that moved across northwestern Utah. This likely stabilized the atmosphere a bit...and additional convective potential may be suppressed for several hours. While earlier runs of the HRRR showed significant wind gusts impacting northwestern Utah and perhaps the Wasatch Front in the 21Z-02Z timeframe, later runs have largely shifted away from this solution. Mesoanalysis correlates a fair amount of inhibition...and guidance suggests this CIN may not be overcome by the end of peak heating. Sunday looks to be a potentially interesting day convection-wise. A weak area of convergence associated with a Pacific trough will shift into northwestern Utah. Mean HREF SBCAPE values will near 1000 J/kg across much of northern Utah by noon to 1 PM. This combined with deep layer shear around 25-30 kts and general synoptic scale lift will support convective development across much of Utah after noon. The most intense convection will likely be across northern Utah. HREF suggests a neighborhood probability of wind gusts in excess of 55 mph around 15-25%, especially near and west of the Great Salt Lake, and 10% or so in excess of 60 mph. The Storm Prediction Center has outlooked this area with a slight risk (level 2/5) for Sunday afternoon and evening including the Wasatch Front. Across central and southern Utah, another day of thunderstorms with the threat of heavy rainfall is expected. Peak rainfall rates in guidance are notably lower than Saturday, correlating well with a net drying trend. That said, the threat of at least isolated flash flooding in the most prone locations will continue Sunday afternoon and evening, especially across central and southern Utah. The Pacific trough will finally shift into the northern High Plains, shifting any large scale forcing for convection to the east. Given there wasn't a front to sweep out the low-level moisture in the low desert areas, expect the threat of isolated flash flooding to persist in any areas that develop convection through at least Monday...if not longer. && .AVIATION... KSLC...There is low confidence in wind direction this afternoon and evening, particularly near any storms. High-based showers and thunderstorms will begin to develop over the Oquirrh Mountains after 20z, with storms potentially moving over the terminal after 21z or so, resulting in gusty and erratic outflow winds reaching 40kts for a brief period (10% chance). BLDU may result in brief VIS reductions. The threat of showers will linger well into the evening/overnight hours (until 09-10z), with a continued threat of outflow winds. REST OF UTAH AND SOUTHWEST WYOMING...High-based showers and thunderstorms will continue to develop across much of the area (all but KCDC-KSGU) this afternoon, first over higher terrain. These storms will be capable of producing gusty and erratic outflow winds up to 40kts (up to 50kts across NW-UT). Storms will likely subside across southern UT between 02-04z, though showers are likely to linger through the overnight hours across the rest of the area...gradually weakening through the night. Outflow winds will result in low confidence in wind direction through much of the valid TAF period. && .FIRE WEATHER...Afternoon and evening showers and thunderstorms will become more isolated through early Monday, and largely tied to terrain. Any showers and thunderstorms this weekend will have the threat of strong, gusty microburst winds. Over the work-week, valley humidities will fall slowly each day, reaching near critical to critical levels as early as Monday. There is little sign of an additional monsoon surge after this weekend until after the next weekend. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && Kruse/Cunningham For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity
In the hours before
Special weather statement, Aug 22, 4:13 PM MDT, 1 hour 1 minute before
Special Weather Statement
National Weather Service Salt Lake City UT
413 PM MDT Sat Aug 22 2026
UTZ101-222300-
Great Salt Lake Desert and Mountains UT-
413 PM MDT Sat Aug 22 2026
...A strong thunderstorm will impact portions of west central Tooele
County through 500 PM MDT
...
At 413 PM MDT, Doppler radar was tracking a strong thunderstorm 15
miles west of Utah Test and Training Range South, or 18 miles
southeast of Wendover, moving northeast at 15 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Utah Test and Training Range South and Bonneville Salt Flats.
This includes Interstate 80 in Utah between mile markers 10 and 17.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
This storm 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 4041 11385 4054 11401 4080 11381 4057 11346
TIME...MOT...LOC 2213Z 220DEG 15KT 4049 11386
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
JCWSpecial weather statement, Aug 22, 4:37 PM MDT, 37 minutes before
Special Weather Statement
National Weather Service Salt Lake City UT
437 PM MDT Sat Aug 22 2026
UTZ101-222315-
Great Salt Lake Desert and Mountains UT-
437 PM MDT Sat Aug 22 2026
...A strong thunderstorm will impact portions of northwestern Tooele
County through 515 PM MDT
...
At 437 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles northwest of Utah Test and Training Range South, or 20 miles
east of Wendover, moving northeast at 25 mph.
HAZARD...Wind gusts of 50 to 55 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Knolls and Utah Test and Training Range South.
This includes Interstate 80 in Utah between mile markers 13 and 45.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
This storm 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 4054 11361 4071 11383 4102 11350 4072 11317
TIME...MOT...LOC 2237Z 238DEG 21KT 4064 11366
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH
JCWLocal storm report, Aug 22, 4:48 PM MDT, 26 minutes before
Preliminary Local Storm Report
National Weather Service Salt Lake City UT
448 PM MDT Sat Aug 22 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 PM Tstm Wnd Gst 4 SW Scipio 39.20N 112.14W
08/22/2026 M59 MPH Millard UT Mesonet
Mesonet station PC291 Scipio Summit.
&&
CRKLocal storm report, Aug 22, 5:03 PM MDT, 11 minutes before
Preliminary Local Storm Report
National Weather Service Salt Lake City UT
503 PM MDT Sat Aug 22 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0450 PM Tstm Wnd Gst 12 W Knolls 40.73N 113.50W
08/22/2026 M67 MPH Tooele UT Mesonet
Mesonet station UT33 I-80 at MP 29.
&&
CRKLocal storm report, Aug 22, 5:11 PM MDT, 3 minutes before
Preliminary Local Storm Report
National Weather Service Salt Lake City UT
511 PM MDT Sat Aug 22 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM Tstm Wnd Gst 12 W Knolls 40.73N 113.50W
08/22/2026 M73 MPH Tooele UT Mesonet
UDOT I-80 @ MP 29.
&&
JCWLocal storm report, Aug 22, 5:12 PM MDT, 2 minutes before
Preliminary Local Storm Report
National Weather Service Salt Lake City UT
512 PM MDT Sat Aug 22 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0505 PM Tstm Wnd Gst 10 W Knolls 40.73N 113.47W
08/22/2026 M75 MPH Tooele UT Mesonet
UDOT Interstate 80.
&&
JCWThe office that day
Everything else NWS Salt Lake City, UT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 9:48 PM MDT | Special Weather Statement | SLC | Tooele | 42 min |
| Aug 22, 12:09 PM MDT | Areal Flood Advisory | SLC | Sevier | 96 min |
| Aug 22, 1:38 PM MDT | Special Weather Statement | SLC | Duchesne | 52 min |
| Aug 22, 1:48 PM MDT | Flash Flood Warning | SLC | Wayne | 3 hr |
| Aug 22, 2:04 PM MDT | Severe Thunderstorm Warning | SLC | Duchesne | 41 min |
| Aug 22, 2:44 PM MDT | Special Weather Statement | SLC | Duchesne | 31 min |
| Aug 22, 3:00 PM MDT | Special Weather Statement | SLC | Salt Lake | 45 min |
| Aug 22, 3:31 PM MDT | Special Weather Statement | SLC | Duchesne | 44 min |
| Aug 22, 3:51 PM MDT | Special Weather Statement | SLC | 39 min | |
| Aug 22, 3:58 PM MDT | Special Weather Statement | SLC | Salt Lake | 47 min |
| Aug 22, 4:13 PM MDT | Special Weather Statement | SLC | Tooele | 47 min |
| Aug 22, 4:37 PM MDT | Special Weather Statement | SLC | Tooele | 38 min |
| Aug 22, 4:50 PM MDT | Severe Thunderstorm Warning | SLC | Tooele | 25 min |
| Aug 22, 5:15 PM MDT | Areal Flood Advisory | SLC | Tooele | 3 hr |
| Aug 22, 5:27 PM MDT | Special Weather Statement | SLC | Tooele | 48 min |
| Aug 22, 5:45 PM MDT | Severe Thunderstorm Warning | SLC | Box Elder, Tooele | 45 min |
Nearby
Severe Thunderstorm Warnings in Utah, 2026Every severe thunderstorm warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.