Severe Thunderstorm Warning 86, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
1250 PM MDT Fri Aug 28 2026

.KEY MESSAGES, Issued 1126 AM MDT Fri Aug 28 2026...

- Scattered showers and thunderstorms will once again impact Utah
  and southwest Wyoming today, with isolated strong to severe
  thunderstorms possible for much of the area this afternoon into
  the early evening. The main threat will be gusty winds to 60
  mph.

- The potential for strong to severe thunderstorms over northern
  portions of the area will increase tomorrow in association with
  a passing cold front, with strong, gusty winds continuing to be
  the main threat.

- With increasing moisture and instability, the threat of flash
  flooding for southern Utah will be elevated both today and
  Saturday. Heavy rain from strong storms over northern Utah will
  also bring isolated flash flooding tonight into tomorrow.

- An active pattern will continue through at least the first half
  of next week.

&&

.DISCUSSION, Issued 1126 AM MDT Fri Aug 28 2026...
Interesting situation setting up for the next few
days with a Pacific Northwest trough moving onshore this morning.
Our ever-present ridge is centered over the Four Corners and the
squeeze between these two features has brought in increase in
southwesterly flow. In this flow, an already moist airmass has
gained moisture, with satellite derived PWs sitting in the 0.8 to
1.0 inch range.

A frontal boundary associated with the Pacific Northwest trough
is stretched across Nevada and Idaho, approaching the northwest
corner of Utah. This has been the focus for showers and a few
embedded thunderstorms this morning, with some additional
generally weak activity having developed ahead of the boundary in
central Utah. The presence of the boundary and the upper jet with
the trough will only add to instability today, which has led the
SPC to put much of the area under a marginal risk for severe
thunderstorms, with gusty winds being the primary threat. With
more widespread coverage of showers and thunderstorms, southern
Utah will see an elevated risk of flash flooding this afternoon,
with prone areas like burn scars and slot canyons behind the main
impact areas.

As the ridge continues eastward out of the area, this will allow
the frontal boundary to move farther into northern Utah and
southwest Wyoming tonight into tomorrow morning, with guidance
continuing to indicate a banded feature along it, bringing good
coverage of showers across much of northern Utah and southwest
Wyoming overnight and into the morning. Embedded stronger showers
could be accompanied by heavy rainfall, so will need to monitor
areas of concern for northern Utah including burn scars and urban
areas with poor drainage.

As the front starts to outrun its upper level support, it is
expected to weaken and stall somewhat in the vicinity of a KELY-
KEVW line late Saturday morning/early Saturday afternoon. With
deep moisture and additional instability provided both from the
main trough and the stalled boundary will bring fairly widespread
coverage of showers and thunderstorms, and ample instability for
scattered coverage of strong to severe cells. Strong, gusty winds
will again be the primary threat but these cells will also be
capable of producing at least small hail along with very heavy
rainfall, bringing an enhanced threat of flooding for northern
Utah as well. The approach of the main trough later Saturday
afternoon into Saturday evening will only improve instability and
is expected to keep showers going, particularly along the frontal
boundary, Saturday night into Sunday morning. This long duration
period of showers only adds to the potential for flooding over
northern portions of the forecast area.

After Sunday morning the main trough, having just made its closest
approach to northern Utah, is forecast to track back northeast.
Overall, this will bring a gradual decrease in coverage of
convection during the day, but this will also get the frontal
boundary moving again, pushing it into southeast Utah during the
afternoon. Thus, there is a high chance that Sunday afternoon will
be the most active period in terms of convection for portions of
southeast Utah, and therefore it is looking increasingly likely
that the highest flash flood threat for that area could be during
this time, with at least some convection continuing along the
boundary during the evening and overnight hours.

Though the Pacific Northwest trough is expected to be well away
from the area by Monday morning, most guidance indicates
convection continuing, particularly for southern Utah, on Monday
as an influx of shortwave energy combines with the existing
boundary and deep moisture, so there is a chance that the
heightened flooding threat for southeast Utah will continue into
much of Monday. Thereafter, with the ridge out of the picture, the
storm track will open up, allowing a variety of troughs to impact
the west during the upcoming week. However, guidance is starting
to converge on solutions that keep many of these features north of
the area, which would bring in drier air and limit the potential
for additional precipitation. Still, the much cooler temperatures
from this weekend's system (highs 5-10F below seasonal normals)
are expected to stick around for much of the upcoming week.

&&

.AVIATION, Issued 1133 AM MDT Fri Aug 28 2026...

KSLC...Winds are favored to trend southwest by late morning, and
then west to northwest by early to mid afternoon, though low
confidence noted given ongoing showers and outflows. Confidence
remains low as thunderstorm activity will increase, increasing
potential for gusty erratic outflow winds. Thunderstorms will also
be capable of brief reductions to CIGS/VIS, with around a 20% chance
of brief MVFR VIS in stronger activity. Winds are expected to shift
south by later in the evening, but scattered thunderstorms and
showers will persist. Thunderstorms once again expected to redevelop
Saturday afternoon.

REST OF UTAH AND SOUTHWEST WYOMING...Ongoing scattered high based
showers will result in some periods of variability to terminal winds
this morning. While terminals will generally favor their diurnally
typical directions, scattered thunderstorm development late morning
through the afternoon will further enhance the potential for gusty
and erratic outflow winds. Activity will also bring potential for
brief reductions to CIGS/VIS, with around a 20% chance of MVFR VIS
noted with any stronger activity atop a terminal. Scattered shower
and thunderstorm chances will then persist later into the evening
and likely for a few hours after midnight as instability persists.

&&

.FIRE WEATHER...High pressure over the Four Corners has added
moisture to an already unusually moist airmass, and anticipated
coverage of showers and thunderstorms will be greater today than
yesterday, with isolated strong to severe thunderstorms capable of
producing wind gusts to around 60 mph. The influence of a Pacific
Northwest trough and its associated cold front will bring a long
period of showers to northern portions of the forecast area Friday
night through Sunday, bringing increasing potential of wetting
rainfall and improved relative humidity values. Strong to severe
thunderstorms, however, will be more scattered in nature during
the day Saturday, bringing an increasing threat of strong and
gusty thunderstorm winds. For Sunday, the focus of showers and
thunderstorms is expected to shift to southeast Utah, bringing the
highest potential of wetting rainfall to that location. The active
pattern and cooler temperatures will continue into at least early
next week, with guidance indicating an increasing potential for
drier conditions for the middle to latter part of the week.

&&

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

PUBLIC...Traphagan
AVIATION...Warthen
FIRE WEATHER...Traphagan

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

Special Weather Statement
National Weather Service Salt Lake City UT
215 PM MDT Fri Aug 28 2026

UTZ125-126-282100-
Upper Sevier River Valleys UT-Southern Mountains UT-
215 PM MDT Fri Aug 28 2026

...A strong thunderstorm will impact portions of southwestern
Garfield and northwestern Kane Counties through 300 PM MDT
...

At 215 PM MDT, Doppler radar was tracking a strong thunderstorm 15
miles southwest of Hatch, or 25 miles northeast of Zion National
Park, moving northeast at 30 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...
Hatch, Glendale, Long Valley Junction, and Hillsdale.

This includes US Route 89 near mile marker 94, and between mile
markers 98 and 122.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3736 11261 3745 11276 3780 11253 3766 11228
      3763 11228
TIME...MOT...LOC 2015Z 213DEG 26KT 3747 11261

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH

JCW

Special Weather Statement
National Weather Service Salt Lake City UT
245 PM MDT Fri Aug 28 2026

UTZ122>125-128-282130-
Southwest Utah UT-South Central Utah UT-Southern Mountains UT-
Zion National Park UT-Lower Washington County UT-
245 PM MDT Fri Aug 28 2026

...A strong thunderstorm will impact portions of southeastern
Washington and west central Kane Counties through 330 PM MDT
...

At 244 PM MDT, Doppler radar was tracking a strong thunderstorm near
Apple Valley, or 14 miles northwest of Colorado City, moving
northeast at 25 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...
Zion National Park, Hurricane, La Verkin, Apple Valley, Toquerville,
Virgin, Springdale, and Rockville.

This includes Interstate 15 between mile markers 35 and 37.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3700 11314 3700 11323 3707 11337 3748 11321
      3729 11282 3699 11313
TIME...MOT...LOC 2044Z 209DEG 20KT 3708 11322

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

JCW

Special Weather Statement
National Weather Service Salt Lake City UT
300 PM MDT Fri Aug 28 2026

UTZ101-102-106-115>117-282145-
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-
300 PM MDT Fri Aug 28 2026

...Strong thunderstorms will impact portions of northeastern Millard,
eastern Juab, southwestern Utah and southeastern Tooele Counties
through 345 PM MDT
...

At 259 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 11 miles southwest of Dugway English Village to
12 miles northwest of Scipio. Movement was northeast at 35 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...
Dugway English Village, Vernon, Tooele Army Depot South, Elberta,
Eureka, Oak City, Rush Valley, Leamington, Lynndyl, Jericho, Tintic
Junction, Faust, Little Sahara State Park, Mills, and Lofgreen.

This includes the following highways...
 Interstate 15 between mile markers 196 and 219.
 US Route 6 between mile markers 99 and 150.

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 4050 11256 4009 11198 3949 11186 3922 11229
      4011 11290
TIME...MOT...LOC 2059Z 221DEG 30KT 4007 11283 3931 11231

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

JCW

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