Flash Flood Warning 128, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
608 AM MDT Wed Sep 16 2026

.KEY MESSAGES, Issued 1044 PM MDT Tue Sep 15 2026...

- Deep moisture will continue to bring an elevated threat of
  flooding to portions of southern and eastern Utah through at
  least Friday.

- A Flood Watch for flash flooding has been issued from late
  tonight through Thursday morning for portions of southern and
  eastern Utah including Zion National Park, Capitol Reef National
  Park, Glen Canyon Recreation Area, the greater Grand Staircase-
  Escalante National Monument area, and the lower Paria including
  Buckskin Gulch and Paria Canyon north of the Arizona border.

- A marginal risk for severe thunderstorms (level 1/5) continues
  for Wednesday morning into Wednesday afternoon across portions
  of northern Utah.

- A marginal risk for excessive rainfall (level 1/4) continues
  for Thursday and Friday across southern and eastern Utah.

&&

.DISCUSSION, Issued 1044 PM MDT Tue Sep 15 2026...
An upper level low will continue to shift down the
Pacific Coast through later Thursday into Friday and then
gradually eject across the Great Basin through Saturday.
Diffluent southwest flow will remain in place, with modest
moisture transport through at least later Thursday. Embedded in
this southwest flow will be a multitude of weak shortwave
troughs or remnant MCVs. This, combined with PWATs in the 96-99th
percentile, and broad ascent will support periods of convection
with very heavy rainfall, especially through Friday morning.

Earlier thunderstorms, with occasional embedded supercells
produced rainfall rates as high as 0.50 inches in 20 minutes,
causing multiple flash floods in the Wahweap, lower Paria
drainages as well as various slot canyons in the San Rafael Swell
including Little Wildhorse north of Goblin Valley State Park.

Current model trends indicate another subtle shortwave ejecting
across northern Arizona/southern Nevada and southwest Utah will
aid in the development of convection overnight through about 6 AM
this morning across lower Washington County, Iron County and
western Kane and Garfield Counties. Rainfall rates in excess of
0.25 inches an hour will be possible with this convection, with
around a 10% chance of rainfall rates in excess of 0.50 inches per
hour. A Flood Watch for flash flooding begins at midnight tonight
and continues through Thursday morning for Zion National Park and
points east. No changes have been made to the going Watch.

The Storm Prediction Center has outlooked portions of northern
Utah for a marginal risk for severe thunderstorms, particularly
for Wednesday morning into early Wednesday afternoon. A few strong
thunderstorms will be possible along the periphery of the deeper
moisture in this area.

Afternoon convection will kick off across the region, with a
multitude of CAMS showing very widespread heavy rain across most
of southern Utah after about 00Z. This may require the expansion
of the Flood Watch into lower Washington, Iron and Beaver Counties
for late Wednesday night into Thursday afternoon. Something to
monitor for future adjustments if CAMS remain consistent.

It is not recommended to have plans into slot canyons, normally
dry washes, and other areas prone to flash flooding over the next
several days. Nearly all National Park and Rec areas are currently
at Probable for the next several days in the flash flood potential
product.

&&

.AVIATION...

KSLC...VFR conditions will persist for the KSLC terminal through the
period. A few lingering showers moving south of the terminal through
~14Z will keep the potential for gusty and erratic winds, but
primarily gusty southerlies prevail. Conditions will be mostly dry
throughout the day with a few highs. Showers and storms are possible
(~25% chance) again tonight.

REST OF UTAH AND SOUTHWEST WYOMING...Showers and thunderstorms
continue the first few hours of the period, generally ending between
12z and 15z. Gusty winds up to 30 knots and brief MVFR conditions
are possible. There will be the chance of showers and thunderstorms
again Wednesday afternoon, but chances generally remain under 30
percent. As better moisture moves into the area starting around 00z,
shower and isolated thunderstorm chances increase for late in the
period. Southern terminals should see prevailing rain around 03z.
Models have some disagreement on timing further north, so have
mostly PROB30 for now, starting about 06z.

&&

.FIRE WEATHER, Issued 344 AM MDT Wed Sep 16 2026...
Monsoon moisture will remain in place, particularly
across southern and eastern Utah, through the next several days.
Frequent lightning along with gusty and erratic winds have been
observed with storms today, and these threats will continue with
any stronger storms that develop throughout the week. Southwest
winds will remain breezy 25-35 mph across western Utah, although
min RH should remain above 20% for most locations.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch from noon MDT today through late tonight for UTZ121-
     129.

     Flood Watch through late tonight for UTZ124-128-130-131.

WY...None.
&&

PUBLIC...
AVIATION...Mahan
FIRE WEATHER...Mahan

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
704 AM MDT Wed Sep 16 2026

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

0430 AM     Non-Tstm Wnd Gst 3 S Faust               40.13N 112.38W
09/16/2026  M67 MPH          Tooele             UT   Mesonet

            Mesonet station VRH Vernon Hill.

0240 AM     Non-Tstm Wnd Gst 2 ENE Provo Canyon      40.34N 111.60W
09/16/2026  M66 MPH          Utah               UT   Mesonet

            Mesonet station PC034 Provo Canyon.

0215 AM     Non-Tstm Wnd Gst 3 W Stockton            40.46N 112.41W
09/16/2026  M66 MPH          Tooele             UT   Mesonet

            Mesonet station SMT South Mountain.

0155 AM     Non-Tstm Wnd Gst 2 SE Dugway             40.23N 112.73W
09/16/2026  M60 MPH          Tooele             UT   Mesonet

            Mesonet station DPG07 English Village.

0230 AM     Non-Tstm Wnd Gst 2 WNW Tooele            40.55N 112.34W
09/16/2026  M59 MPH          Tooele             UT   Mesonet

            Mesonet station UT112 SR-112 at MP 6 Utah
            Avenue.

0140 AM     Non-Tstm Wnd Gst 10 SSW Dugway           40.11N 112.81W
09/16/2026  M58 MPH          Tooele             UT   Mesonet

            Mesonet station DPG13 Durand Road.

&&

Special Weather Statement
National Weather Service Salt Lake City UT
721 AM MDT Wed Sep 16 2026

UTZ112-161400-
Western Uinta Mountains UT-
721 AM MDT Wed Sep 16 2026

...A strong thunderstorm will impact portions of northeastern
Wasatch, west central Duchesne and south central Summit Counties
through 800 AM MDT
...

At 721 AM MDT, Doppler radar was tracking a strong thunderstorm
capable of producing a landspout 7 miles east of Timber Lakes, or 16
miles east of Heber City, moving northeast at 25 mph.

HAZARD...Landspouts, wind gusts of 50 to 55 mph, and penny size
         hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible. Gusty winds
         could knock down tree limbs and blow around unsecured
         objects.

Locations impacted include...
Timber Lakes and Trial Lk.

This includes the following highways...
 Utah Route 35 between mile markers 8 and 27.
 Mirror Lake Highway between mile markers 9 and 28.

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 4034 11104 4043 11125 4076 11107 4062 11076
TIME...MOT...LOC 1321Z 210DEG 22KT 4046 11110

LANDSPOUT...POSSIBLE
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...55 MPH

HRM

Special Weather Statement
National Weather Service Salt Lake City UT
738 AM MDT Wed Sep 16 2026

UTZ128-161415-
South Central Utah UT-
738 AM MDT Wed Sep 16 2026

...A strong thunderstorm will impact portions of south central
Garfield and northeastern Kane Counties through 815 AM MDT
...

At 737 AM MDT, Doppler radar was tracking a strong thunderstorm 26
miles southeast of Escalante, moving northeast at 25 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.

This storm will remain over mainly rural areas of south central
Garfield and northeastern Kane Counties, including Brimstone, Spooky
and Peekaboo slot canyons.

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 3737 11116 3743 11132 3772 11124 3761 11099
TIME...MOT...LOC 1337Z 205DEG 24KT 3752 11122

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

HRM

Preliminary Local Storm Report...Corrected
National Weather Service Salt Lake City UT
1003 AM MDT Wed Sep 16 2026

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

0140 AM     Tstm Wnd Gst     10 SSW Dugway           40.11N 112.81W
09/16/2026  M58 MPH          Tooele             UT   Mesonet

            Mesonet station DPG13 Durand Road.

0155 AM     Tstm Wnd Gst     2 SE Dugway             40.23N 112.73W
09/16/2026  M60 MPH          Tooele             UT   Mesonet

            Mesonet station DPG07 English Village.

0215 AM     Tstm Wnd Gst     3 W Stockton            40.46N 112.41W
09/16/2026  M66 MPH          Tooele             UT   Mesonet

            Mesonet station SMT South Mountain.

0230 AM     Tstm Wnd Gst     2 WNW Tooele            40.55N 112.34W
09/16/2026  M59 MPH          Tooele             UT   Mesonet

            Mesonet station UT112 SR-112 at MP 6 Utah
            Avenue.

0240 AM     Tstm Wnd Gst     2 ENE Provo Canyon      40.34N 111.60W
09/16/2026  M66 MPH          Utah               UT   Mesonet

            Mesonet station PC034 Provo Canyon.

0430 AM     Tstm Wnd Gst     3 S Faust               40.13N 112.38W
09/16/2026  M67 MPH          Tooele             UT   Mesonet

            Mesonet station VRH Vernon Hill.

&&

Special Weather Statement
National Weather Service Salt Lake City UT
1104 AM MDT Wed Sep 16 2026

UTZ128-131-161745-
South Central Utah UT-Glen Canyon Recreation Area/Lake Powell UT-
1104 AM MDT Wed Sep 16 2026

...A strong thunderstorm will impact portions of southwestern San
Juan and southeastern Kane Counties through 1145 AM MDT
...

At 1103 AM MDT, Doppler radar was tracking a strong thunderstorm near
Lake Powell, or 56 miles southeast of Escalante, moving northeast at
20 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...
Lake Powell from east to Wahweap to Dangling Rope Marina.

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 3700 11130 3739 11114 3727 11083 3700 11104
TIME...MOT...LOC 1703Z 204DEG 19KT 3702 11118

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

CRK