Alert archive / Utah / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 41, NWS Salt Lake City, UT

September 12, 2025Garfield County, Kane County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Sep 12, 2025, 6:28 AM MDT for Garfield County, Kane County, Utah. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 12, 2025, 6:28 AM MDT (12:28 UTC)
Expired
Sep 12, 2025, 7:00 AM MDT
In force
32 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Garfield County, UT, Kane County, UT

The radar

The Cedar City radar (KICX), 105 km from the middle of the area, began a volume at 12:31 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.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 0.5 hours before the alert went out and 260 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.

Skew-T log-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 2025-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2025-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 296 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1323 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
296 m²/s²
0-3 km storm-relative helicity
350 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 Sep 12, 4:54 AM MDT, 1 hour 34 minutes earlier.

Area forecast discussion, Sep 12, 4:54 AM MDT, 1 hour 34 minutes before
Area Forecast Discussion...CORRECTED
National Weather Service Salt Lake City UT
454 AM MDT Fri Sep 12 2025

.SYNOPSIS...A slow moving upper level low will impact the region
through Saturday. Short-lived high pressure Sunday will transition
to a cold front crossing the state Monday into Tuesday.

&&

.DISCUSSION...A slow moving upper level will continue to impact
much of Utah through Saturday. Early morning upper air and
satellite analysis indicates an upper level low is centered
north of Reno, NV. Southwest flow remains across Utah, while a
series of shortwave troughs rotate around the parent low across
Oregon and Nevada. Light showers continue across portions of
northern Utah in association with subtle jet enhancement.

By this afternoon, a shortwave trough ejecting ahead of the main
circulation in southwest flow will provide support for convection
across the eastern half of Utah. HREF mean SBCAPE across Utah will
range from around 250-500 J/kg, with deep layer shear around
40-50kts. Expect showers and a few thunderstorms to develop
through the afternoon and evening from roughly I-15 eastward.

Similar conditions are expected Saturday as the trough axis
finally passes overhead.

By Sunday, shortwave ridging will shift across the region. The
next upper level low is expected to slowly cross the northern
Intermountain Region Monday through Wednesday. This system will
likely push a cold front slowly through the state Monday into
Tuesday.

Around 30% of the ensemble members bring light precipitation to
northern Utah (mainly Provo and northward) with this front, while
70% indicate this front is sufficiently removed from any forcing
to be dry. More probable is the reduction of temperatures by at
least 2-3 degrees Monday and another 2-3 degrees Tuesday, mainly
across northern and central Utah.

&&

.AVIATION...KSLC...VFR conditions will persist for the KSLC
terminal through the period. Variable winds will gradually switch
over to light southerly winds that will become gusty during the
day. Conditions will remain dry with some scattered mid level
clouds.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist
for the entire airspace through the period. Mostly dry conditions
and some mid level clouds will continue with afternoon convection
staying confined to far eastern portions of the airspace unlikely
to impact any terminals. Southerly winds will increase during the
day.

&&

.FIRE WEATHER...A slow moving upper level system (that we've been
talking about for days) will continue to shift across the Great
Basin through Saturday. Expect showers and thunderstorms to
develop Friday and Saturday afternoon and evening across the
eastern half of Utah.

After a brief period of high pressure Sunday, another slow moving
upper level low will cross the northern Intermountain Region
Monday into Wednesday. This will bring a cold front slowly through
the state Monday into Tuesday. Around 30% of the ensemble members
bring light precipitation into northern Utah with this cold
front, while the remainder indicate a largely dry front.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

Kruse/Mahan

For more information from NOAA's National Weather Service visit...
http://weather.gov/saltlakecity

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 12, 6:30 AM MDTSpecial Weather StatementSLCWayne45 min
Sep 12, 6:55 AM MDTSevere Thunderstorm WarningSLCGarfield35 min
Sep 12, 7:07 AM MDTSpecial Weather StatementSLCWayne38 min
Sep 12, 7:16 AM MDTSevere Thunderstorm WarningSLCEmery, Wayne44 min
Sep 12, 7:52 AM MDTSpecial Weather StatementSLCWayne38 min
Sep 12, 7:57 AM MDTSevere Thunderstorm WarningSLCEmery, Wayne33 min
Sep 12, 8:17 AM MDTFlash Flood Warning Considerable damage threatSLCWayne3 hr
Sep 12, 8:27 AM MDTSpecial Weather StatementSLC48 min
Sep 12, 8:53 AM MDTSevere Thunderstorm WarningSLCEmery, Wayne37 min
Sep 12, 9:15 AM MDTFlash Flood Warning Considerable damage threatSLCEmery, Wayne3 hr
Sep 12, 11:30 AM MDTSpecial Weather StatementSLC30 min
Sep 12, 3:08 PM MDTSpecial Weather StatementSLCDuchesne52 min
Sep 12, 3:17 PM MDTSpecial Weather StatementSLCCarbon28 min

Nearby

Severe Thunderstorm Warnings in Utah, 2025Every severe thunderstorm warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.