Special Weather Statement, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
1117 AM MDT Mon Aug 31 2026

.KEY MESSAGES...

- Numerous showers and thunderstorms capable of producing heavy
  rain this afternoon and evening will result in a heightened risk
  of flash flooding for the southern two-thirds of Utah, where a
  Flood Watch for flash flooding is in effect through this
  evening.

- The threat of flooding is highest across slot canyons, normally
  dry washes, slick rock areas, recent burn scars as well as
  areas that have already received very heavy rainfall this
  weekend including the Sanpete and Sevier Valleys, Castle
  Country, and the San Rafael Swell.

- After some modest drying for the middle of the week, there is an
  increasing probability that deep moisture associated with a
  tropical cyclone in the Eastern Pacific will spread northward
  into Utah ahead of a Pacific disturbance for Labor Day weekend.

&&

.DISCUSSION...High pressure remains in place over the central
United States this morning, with a trough moving onshore over
California and a stronger trough moving into the Dakotas. In
between these features, Utah and southwest Wyoming are under a
southerly flow that is drawing deep monsoonal moisture northward.
Satellite derived PW values remain around 1.0 inch over southern
Utah, with values predominately in the 0.7 to 0.9 range elsewhere,
with the exception of far northern Utah.

Showers and thunderstorms have been bringing heavy rainfall across
portions of southern Utah through the morning, with many of these
cells producing flash flooding. The threat of flooding will only
increase and expand this afternoon as the California trough moves
across Utah, providing additional moisture and instability.
Increased coverage of convection will only increase a risk of
flash flooding that has been elevated all weekend, as indicated by
the rare moderate (level 3 of 4) risk of excessive rainfall
indicated bu the Weather Prediction Center. Additionally, many
areas, especially eastern Utah, have already seen heavy rain,
leading to saturated soils, further increasing the risk. With this
in mind, have expanded the going Flood Watch for flash flooding
to include the Book Cliffs, Uinta Basin, and west central and
southwest Utah.

The California trough is expected to exit the area by tomorrow
morning, with another low approaching the northern California
coast. Guidance indicates this will allow the southerly flow to
advect drier air into the area, at least over western Utah
beginning tomorrow afternoon, with the drier air becoming more
widespread Wednesday into Thursday as the second trough moves
across the Pacific Northwest into the Dakotas. For Tuesday,
guidance overall looks to be unusually quick with diminishing the
potential of thunderstorms and thus flash flooding, so have
increased POPs given recent trends.

The drying trend looks to be short lived, unfortunately, with a
lot of the longer range guidance indicating the southerly flow
increasing Friday into the Labor Day weekend with the approach of
another Pacific Northwest trough. This would allow a tap into an
even more deeply moist airmass from a tropical system, a rather
substantial influx of moisture and something we are keeping a very
close eye on.

&&

.AVIATION, Issued 1046 PM MDT Sun Aug 30 2026...

KSLC...There is around a 40% chance of light north to variable
winds for a period overnight. Southerly winds likely to increase
by mid morning Monday. Monday afternoon will see convection
chances increase through the afternoon, especially after around
21Z to 04Z Tuesday. Storms will be capable of brief periods of
heavy rain, lightning, and gusty erratic outflow winds.
Additionally, stronger storms will be capable of brief categorical
VIS reductions to MVFR or so, as well as lowered CIGS.

REST OF UTAH AND SOUTHWEST WYOMING...Isolated showers and
thunderstorms will be possible overnight, especially across central
Utah. Winds will generally favor a diurnally normal direction. on
Sunday, southerly flow will increase as will cloud cover. Afternoon
showers and thunderstorms will once again become more widespread
through the afternoon hours, especially along and east of Utah's
high terrain. Like previous days, these storms will be capable of
periods of heavy rain, lightning, gusty erratic outflow winds, and
small hail. Additionally, the stronger storms will be capable of
periods of decreased VIS to around MFVR or so, as well as some
lowered CIGS. In general, coverage of showers and thunderstorms will
begin to wane late evening into the overnight hours.

&&

.FIRE WEATHER...Showers and thunderstorms are continuing to
develop over southern Utah this morning and will only increase in
coverage across the entire state this afternoon into the early
evening as a low pressure system crosses the area in an already
moist airmass. This will bring a high chance (50 to 85 percent) of
wetting rain, particularly for the higher terrain of central and
southern Utah. Relative humidities will also remain on the high
side, with very few locations falling below 30 percent. Drier air
will start to move in from the west on Tuesday, but this should
not be noticeable for much of the area until Wednesday into
Thursday. This is likely to push minimum relative humidity values
into the teens across western Utah Wednesday into Thursday. In
combination with breezy southerly winds due to a low along the
Pacific coast, this could bring area of critical fire weather
conditions. The period of dry weather should be short lived,
however, with guidance increasingly indicating a substantial surge
of tropical moisture into Utah over the weekend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch until 9 PM MDT this evening for UTZ113>131.

WY...None.
&&

PUBLIC...Traphagan
AVIATION...Webber
FIRE WEATHER...Traphagan

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

Preliminary Local Storm Report
National Weather Service Salt Lake City UT
837 AM MDT Mon Aug 31 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     Flash Flood      14 WNW Big Water        37.11N 111.91W
08/31/2026                   Kane               UT   Official NWS Obs

            429 cfs flood wave reported by the gauge at
            US-89.

&&

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Preliminary Local Storm Report
National Weather Service Salt Lake City UT
1029 AM MDT Mon Aug 31 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     Flash Flood      24 W Big Water          37.13N 112.09W
08/30/2026                   Kane               UT   Public

            Buckskin running high at US-89.

&&

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Preliminary Local Storm Report
National Weather Service Salt Lake City UT
1053 AM MDT Mon Aug 31 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0915 AM     Flash Flood      4 N Escalante           37.83N 111.61W
08/31/2026                   Garfield           UT   Official NWS Obs

            Gauge on upper Pine Creek showed a flash
            flood wave around 171 cfs heading down the
            drainage toward the Escalante River.

&&

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Special Weather Statement
National Weather Service Salt Lake City UT
1059 AM MDT Mon Aug 31 2026

UTZ122-125-311745-
Southwest Utah UT-Southern Mountains UT-
1059 AM MDT Mon Aug 31 2026

...A strong thunderstorm will impact portions of central Iron County
through 1145 AM MDT
...

At 1058 AM MDT, Doppler radar was tracking a strong thunderstorm 15
miles north of New Harmony, or 16 miles west of Cedar City, moving
northeast at 25 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel size 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...
Cedar City, Enoch, Parowan, Paragonah, and Summit.

This includes the following highways...
 Interstate 15 between mile markers 61 and 81.
 Utah Route 56 between mile markers 38 and 58.

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.

&&

LAT...LON 3758 11340 3774 11351 3806 11291 3783 11274
TIME...MOT...LOC 1658Z 205DEG 20KT 3770 11339

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

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Preliminary Local Storm Report
National Weather Service Salt Lake City UT
1109 AM MDT Mon Aug 31 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1025 AM     Flash Flood      2 NE Escalante          37.78N 111.57W
08/31/2026                   Garfield           UT   Official NWS Obs

            River Gauge on the Escalante at Escalante
            indicates a 433 cfs flood wave hit the gauge
            at 1025. The flow was still increasing.

&&

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Special Weather Statement
National Weather Service Salt Lake City UT
1121 AM MDT Mon Aug 31 2026

UTZ124-125-311800-
Southern Mountains UT-Zion National Park UT-
1121 AM MDT Mon Aug 31 2026

...A strong thunderstorm will impact portions of east central
Washington, northwestern Kane and south central Iron Counties through
NOON MDT
...

At 1121 AM MDT, Doppler radar was tracking a strong thunderstorm near
Zion National Park, moving northeast at 15 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel size 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...
Zion National Park and Cedar Breaks National Monument.

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.

&&

LAT...LON 3731 11299 3738 11312 3767 11289 3750 11263
TIME...MOT...LOC 1721Z 219DEG 13KT 3739 11298

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

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