Flash Flood Warning 84, NWS Salt Lake City, UT

278 
WGUS75 KSLC 202237
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
437 PM MDT Sat Aug 20 2022

UTC007-202300-
/O.CON.KSLC.FF.W.0084.000000T0000Z-220820T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carbon UT-
437 PM MDT Sat Aug 20 2022

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 5 PM MDT THIS 
AFTERNOON FOR NORTHWESTERN CARBON COUNTY...

At 437 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 1 inch of rain has 
fallen. Flash flooding is ongoing or expected to begin shortly.

Excessive rainfall over the Trail Mountain burn scar has resulted in 
a debris flow moving through Huntington Canyon, and State Route 31 
is closed. The debris flow can consist of rock, mud, vegetation and 
other loose materials.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Castle Gate.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry washes is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3977 11094 3977 11089 3974 11087 3972 11088
      3973 11093 3975 11096

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MPS

506 
WGUS75 KSLC 202255
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
455 PM MDT Sat Aug 20 2022

UTC007-202305-
/O.EXP.KSLC.FF.W.0084.000000T0000Z-220820T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carbon UT-
455 PM MDT Sat Aug 20 2022

...FLASH FLOOD WARNING WILL EXPIRE AT 5 PM MDT THIS AFTERNOON FOR 
NORTHWESTERN CARBON COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3977 11094 3977 11089 3974 11087 3972 11088
      3973 11093 3975 11096

$$

MPS

Area Forecast Discussion
National Weather Service Salt Lake City UT
335 AM MDT Sat Aug 20 2022

.SYNOPSIS...A low pressure system will cross northern Utah today,
enhancing coverage of showers and thunderstorms. Deep moisture
will also keep a threat of convection over central and southern
Utah this afternoon into the early evening. High pressure will
build over the Great Basin to start the week, bringing a drying
trend to Utah and southwest Wyoming through midweek.

&&

.SHORT TERM (Through 12Z/6AM Monday)...A weakly organized low
pressure system is centered over northwest Utah this morning.
Around this circulation, showers and thunderstorms have persisted
over portions of northern Utah during the overnight hours, with
the greatest coverage of activity currently near the Utah/Idaho
border. These showers will tend to diminish early this morning,
though additional showers will develop throughout the day, focused
near the low that will continue to slowly track east. Convection
will be greatest in coverage during the afternoon and early
evening, aided by daytime heating, with some convection also
possible away from the low over the higher terrain of central and
southern Utah. There will be enough flow aloft to warrant some
drift into the valleys, bringing a bit of a heightened risk of
flooding. However, the threat seems a bit too isolated at this
time to warrant a Flood Watch.

The low is on track to exit the forecast area tonight into early
tomorrow, with high pressure building into the Great Basin behind
it. The position of this ridge will bring a more northwesterly
flow over Utah and southwest Wyoming, advecting drier air into the
area for the early part of the upcoming week. Still anticipating
notable coverage of convection Sunday afternoon and evening,
primarily for areas east of I-15, with a noticeable decrease in
convective activity for western areas as the drier air starts to
move in. Temperatures will remain just below seasonal normals,
though areas that are drying out will see a few degrees of
warming.

.LONG TERM (After 12Z/6AM Monday)...Long term forecast period begins
with departing shortwave energy sliding southward through CO, while
mid level ridging noses in from the west. Aloft, this promotes more
deep layer zonal to northwesterly flow, and thus drier air and lower
overall PoPs for much of the forecast area. The exception to this
appears to be some meager diurnally driven PoPs along higher
terrain, as well as portions of eastern UT and southwest WY where
the departing shortwave may aid in some isolated precipitation
development on Monday. On Tuesday, the pattern appears to show
little change other than even less synoptic scale forcing for
ascent, and as such PoPs lower further and become even more
constrained to higher terrain during the afternoon.

By Wednesday, mid level ridging gradually migrates across UT in
response to amplifying troughing in the PacNW. This combination will
promote deep layer flow shifting a bit more zonal to southwesterly,
and will allow moisture to begin to creep back into southern UT. As
such, higher precipitation chances also return to southern UT, with
more modest chances in the high terrain elsewhere across the
forecast region.

Guidance begins to diverge somewhat on the exact setup for the
remainder of the forecast period, but remains in reasonable enough
agreement to get a decent picture of what to expect. For Thursday,
moisture increases a bit more areawide, while flow aloft
accelerates, and modest PVA is imparted on the region while the
PacNW trough migrates eastward. As a result, Thursday currently
shows the highest PoPs in the long term forecast, though confidence
remains a bit higher for increased coverage in south UT, east UT,
southwest WY, and particularly the higher terrain therein. For
Friday on into the weekend, the PacNW trough starts to dig into the
Northern Plains, resulting in subtle mid level height falls over the
forecast region. While this helps provide a bit of synoptic scale
forcing, it will also help displace the ridge, leading to some
questions on what amount of moisture remains in the area. Euro
ensemble appears a bit drier than that of the Canadian/GEFS... But
in any case, it appears there should remain enough support for
modest PoPs to persist from southern UT and eastern UT into
southwest WY, particularly along higher terrain.

In regards to temperatures, the pattern looks to keep afternoon
highs near to slightly above normal through mid week, and near to
below normal thereafter with the increasing PoPs and associated
cloud cover. Overnight lows appear to generally remain near to above
normal throughout the forecast period. Per usual, day to day temps
will be influenced by precip and cloud coverage, and what may linger
into the overnight hours.

&&

.AVIATION...KSLC...Disturbance slowly moving through keeps
conditions unsettled for much of TAF period. Isolated to scattered
showers a continued possibility, with coverage increasing Saturday
afternoon. A few thunderstorms possible. Gusty erratic outflow winds
and deteriorated CIGS/VIS possible in any convection directly atop
the terminal. Otherwise, winds largely remain diurnal in nature, and
precip begins to wane by late Saturday evening. Generally, expect
VFR BKN to OVC CIGS, becoming more SCT by late Saturday.

.REST OF UTAH AND SOUTHWEST WYOMING...A slow moving disturbance will
keep weather unsettled at area terminals through much of the TAF
period. For N UT / SW WY, expect a bit more coverage in precip, with
denser cloud cover as well. Coverage expected to further increase
Saturday afternoon, with a few thunderstorms possible. For S UT,
primary rain/thunderstorm chances will hold off until Saturday
afternoon, and persist into the evening hours. Areawide,
precipitation chances will begin to wane by late Saturday evening,
with cloud cover becoming less dense as well thereafter. Gusty
erratic outflow winds and deteriorated CIGS/VIS possible for any
convection directly impacting area terminals. Otherwise, winds
largely expected to follow a typical diurnal pattern.

&&

.FIRE WEATHER...A moist airmass will remain in place across Utah
today. A low pressure system is currently centered over northwest
Utah and will track eastward during the day, exiting the state
tonight. Showers and thunderstorms today will be most widespread
in the vicinity of the low, though convection is likely across the
higher terrain of central and southern Utah as well, with some
drift into the adjacent valleys. Behind the exiting low, high
pressure will build into the Great Basin, putting Utah under
northwest flow aloft that with advect drier air into the air for
the early part of the upcoming week. As a result, the area will
see a downward trend in coverage of showers and thunderstorms.
Monsoonal moisture may return toward the end of the upcoming week.

&&

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

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM/AVIATION...Warthen

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

For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php

Special Weather Statement
National Weather Service Salt Lake City UT
127 PM MDT Sat Aug 20 2022

UTZ125>128-202000-
South Central Utah UT-Upper Sevier River Valleys UT-
Bryce Canyon Country UT-Southern Mountains UT-
127 PM MDT Sat Aug 20 2022

...A strong thunderstorm will impact portions of southwestern
Garfield County through 200 PM MDT...

At 126 PM MDT, Doppler radar was tracking a strong thunderstorm over
Red Canyon, or 36 miles south of Junction, moving east at 15 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

Locations impacted include...
Red Canyon, Bryce Canyon National Park, Tropic, Rubys Inn and
Hillsdale.

This includes Utah Route 12 between mile markers 1 and 23.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3765 11239 3781 11236 3779 11201 3756 11207
TIME...MOT...LOC 1926Z 277DEG 12KT 3771 11230

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

AD

Special Weather Statement
National Weather Service Salt Lake City UT
138 PM MDT Sat Aug 20 2022

UTZ125-128-202015-
South Central Utah UT-Southern Mountains UT-
138 PM MDT Sat Aug 20 2022

...A strong thunderstorm will impact portions of south central
Garfield County through 215 PM MDT...

At 138 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles west of Escalante. This storm is moving southeast at 10 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

Locations impacted include...
Escalante.

This includes Utah Route 12 between mile markers 44 and 67.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3763 11183 3780 11181 3778 11148 3754 11155
TIME...MOT...LOC 1938Z 251DEG 3KT 3771 11178

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

AD

Special Weather Statement
National Weather Service Salt Lake City UT
149 PM MDT Sat Aug 20 2022

UTZ122-202015-
Southwest Utah UT-
149 PM MDT Sat Aug 20 2022

...A strong thunderstorm will impact portions of southwestern Beaver
and north central Iron Counties through 215 PM MDT...

At 149 PM MDT, Doppler radar was tracking a strong thunderstorm 32
miles east of Ranch Campground, or 35 miles northeast of Ursine,
moving east at 5 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This storm will remain over mainly rural areas of southwestern Beaver
and north central Iron Counties.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3816 11371 3832 11366 3830 11335 3805 11345
TIME...MOT...LOC 1949Z 285DEG 5KT 3822 11363

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

AD

Special Weather Statement
National Weather Service Salt Lake City UT
225 PM MDT Sat Aug 20 2022

UTZ125-202100-
Southern Mountains UT-
225 PM MDT Sat Aug 20 2022

...A strong thunderstorm will impact portions of northwestern Kane
County through 300 PM MDT...

At 225 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles south of Cedar Breaks National Monument, or 17 miles northeast
of Zion National Park, moving southeast at 10 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This storm will remain over mainly rural areas of northwestern Kane
County.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3745 11289 3755 11281 3747 11256 3731 11271
TIME...MOT...LOC 2025Z 304DEG 7KT 3746 11279

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

AD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
244 PM MDT SAT AUG 20 2022

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

0214 PM     DEBRIS FLOW      10 W SOLDIER SUMMIT     39.95N 111.26W
08/20/2022                   UTAH               UT   DEPT OF HIGHWAYS

            UDOT REPORTED A DEBRIS FLOW ON US HIGHWAY 6 AT MP 200
            THAT BLOCKED THE ROAD AND CAUSED A CLOSURE ON THE
            WESTBOUND LANES OF TRAVEL.

&&

BRANDON.SELBIG

Special Weather Statement
National Weather Service Salt Lake City UT
255 PM MDT Sat Aug 20 2022

UTZ128-202130-
South Central Utah UT-
255 PM MDT Sat Aug 20 2022

...A strong thunderstorm will impact portions of south central Kane
County through 330 PM MDT...

At 254 PM MDT, Doppler radar was tracking a strong thunderstorm 24
miles south of Henrieville, or 26 miles northeast of Kanab, moving
south at 15 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 Kane
County.

This includes US Route 89 between mile markers 23 and 44.

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 3726 11224 3731 11204 3713 11189 3703 11219
TIME...MOT...LOC 2054Z 342DEG 13KT 3722 11212

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

LC