Severe Thunderstorm Warning 40, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
521 PM MDT Sat Jul 18 2026

.KEY MESSAGES, Issued 1213 PM MDT Sat Jul 18 2026...

- Scattered showers and thunderstorms are expected to develop across
portions of central, southern, northeast UT, and southwest WY each
afternoon within this forecast as monsoonal moisture continues
making its way north.

- The risk for flash flooding continues across the majority of the
forecast area, highlighted by WPC with a Marginal Risk (1/4) of
exceeding flash flood guidance each day encompassing nearly all of
UT. A Slight Risk (2/4) of exceeding flash flood guidance exists
across southern UT this afternoon, Sunday afternoon across
southwest UT, and Tuesday afternoon across southwest UT.

- A Flash Flood Watch remains in effect for southern UT and portions
of Central UT this afternoon, ending around midnight. Additionally,
another Flash Flood Watch has been issued for southern UT and
portions of central UT tomorrow afternoon.

&&

.DISCUSSION, Issued 1213 PM MDT Sat Jul 18 2026...
 The monsoonal pattern persists across the
southwest as broad ridging remains overhead. Beneath this ridge,
PWATs in excess of 1" continue to overspread most valley locations
with southwest UT potentially exceeding 1.6" PWATs once again this
afternoon. Daily chances for showers, thunderstorms, and potentially
flash flooding continue for the foreseeable future across southern
and central UT with this pattern in place. Modest moisture return
continues to push across northern UT, though most storms have
remained anchored to the terrain further east each afternoon due to
drier PBL conditions across northwest UT valleys and considerably
weaker steering flow. This brings great uncertainty to the
forecast each day, keeping PoPs generally 10% or less across most
of the Wasatch Front and northwest UT. Some deeper boundary layer
moisture may build into the area Monday afternoon, though
considerable uncertainty remains.

With PWAT anomalies statewide once again ranging from 0.5" to nearly
1" this afternoon, the threat for flash flooding is expected to
continue across southern and central UT. Tall, skinny CAPE profiles
(potentially in excess of 1000J/kg) with a deeper warm cloud layer
supports yet another round of efficient rainmakers with heavy rain
expected from well established storms. The stronger instability axis
with CAPE values >= 1000J/kg once again resides across southwestern
UT, supported by both SPC Mesoanalysis and current CAM guidance,
with storms expected to initiate along higher terrain and propagate
down terrain toward the instability gradients. A similar failure
mode to yesterday exists across southeast UT where cold pool
development and eastward propagation leads to strong CIN as storms
propagate southwest, resulting in shallower convection with eastern
extent favoring weaker storms. A few wetter storms are still
possible, though not nearly as widespread as coverage is forecast
across southwest UT.

Forecast guidance continues to hone in on the monsoonal pattern
persisting with weak steering flow aloft continuing as ridging
remains overhead through the remainder of the forecast period.
Sunday and Tuesday stand out in particular as robust mid-level
moisture rides along the southern periphery of the ridge into
southern UT, reflected by the WPC Slight Risk (2/4) for excessive
rainfall for each respective day. Monday has some potential for more
isolated flash flooding, though drier mid-levels may hinder vertical
extent of these storms and moisture quality overall.

&&

.AVIATION...

KSLC...Convection chances further diminish into late Saturday
evening, with winds favored to trend SE through the overnight (~10-
20% chance more easterly briefly). Cloud cover will linger, but
remain VFR generally above 10 kft. Sunday will see a similar
forecast progression with winds expected to shift NW ~17-19Z, and
low chances (10-20%) or convection directly impacting the terminal.
Indirectly, there will still be potential for gusty erratic outflows.

REST OF UTAH AND SOUTHWEST WYOMING...Ongoing convection will wane
through the evening, with remnant outflows resulting in periods of
variability to winds at area terminals. Terminals eventually settle
out more diurnally normal to light and variable, with lingering VFR
cloud cover. The forecast Sunday is not too dissimilar to that of
previous days. Anticipate winds to initially trend diurnally normal,
with afternoon convection developing along the high terrain and then
spreading to adjacent areas in time. Aside from brief periods of
reduced CIGS/VIS from any stronger storms directly atop a terminal,
this activity will bring potential for gusty and erratic outflow
winds through the day.

&&

.FIRE WEATHER, Issued 1215 PM MDT Sat Jul 18 2026...
Monsoonal moisture continues to surge north
into UT increasing humidities while raising chances for showers and
thunderstorms across the state, both serving to moderate fire
weather conditions. Chances for showers and thunderstorms remain
highest across central and southern UT, high terrain across northern
UT, and the Uintas ranging from 60-90%. A wetting rain remains
favored this afternoon across each mentioned location. Expect
showers and thunderstorms to develop along higher terrain parallel
to I-15 each afternoon over the next several days around 1200-1300
with gusty outflow winds, heavy rainfall, and lightning. Winds will
generally remain light terrain driven / diurnal over the next
several days.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch until midnight MDT tonight for UTZ122>128.

     Flood Watch from Sunday afternoon through Sunday evening for
     UTZ122>128.

WY...None.
&&

PUBLIC...Worster
AVIATION...Warthen
FIRE WEATHER...Worster

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
534 PM MDT Sat Jul 18 2026

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

0500 PM     Flash Flood      1 E Bicknell            38.34N 111.52W
07/17/2026                   Wayne              UT   Law Enforcement

            *** 5 FATAL ***
            Wayne County Sheriff reports 5 deceased in
            wash near Sunglow Campground, believed to
            have fallen victim to flooding from heavy
            rainfall.

&&

DEC