Special Weather Statement, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
357 PM MDT Sun Jul 25 2021

.SYNOPSIS...Moisture over southern Utah will spread northward
across the remainder of Utah and southwest Wyoming Monday and
Tuesday. Unsettled conditions will continue for much of the week.

&&

.SHORT TERM (Through 12Z Wednesday)...High pressure remains parked
just west of the forecast area this afternoon as an upper low
moves west across southern Arizona. Hot, dry, and stable
conditions are being observed over northern Utah and southwest
Wyoming in northerly flow aloft, that is also bringing a good
amount of smoke into the air from western wildfires. Moisture
increases going southward, with widespread PWs in excess of 1.0
inch over southern Utah into eastern Utah. Showers and
thunderstorms, some of which have already produced heavy rain and
gusty winds, have initially been focused over the higher terrain
but are starting to drift into some valley locations. The storms
will continue into the evening before weakening with the loss of
daytime heating.

The Arizona low will continue west, reaching the southern
California coast tomorrow. This will shift the position of the
high to the east, allowing a more southerly flow to develop over
Utah and southwest Wyoming tomorrow. This will act to draw
moisture back northward and also decrease the amount of smoke in
the air for northern Utah. The threat of heavy rain tomorrow
spreads into central Utah, with the deeper moisture spreading
across the majority of the forecast area by Tuesday.

.LONG TERM (After 12Z Wednesday)...Wednesday could bring a lull in
monsoon action. Ridging to the east strengthens in a wide range of
guidance, bringing drier flow into southwest Wyoming and Utah.
Showers and thunderstorms are still expected, but will likely be
more isolated and near higher terrain.

There is good ensemble agreement in the ridge tilting as it moves
southeast in an orientation that will increase monsoonal moisture
advection. This synoptic set up should remain similar for a few
days. Precipitable water values over 1" are likely to build into
southwest Wyoming and northern Utah Thursday. Portions of northern
Utah are well above 100% normal in the GEFS and EPS mean
precipitable water amounts into the weekend. There won't be as much
of a moisture gradient with increases to the north, but precipitable
water will remain over 1" for most places further south. More
afternoon and evening convection is expected with storms moving
south to north. Flash flooding will remain a threat.

Temperatures are expected to trend cooler as moisture increases.
From near average temperatures Wednesday, the remainder of the week
will be a few degrees cooler than average in southwest Wyoming and
northern Utah. Depending mainly on precipitation, toward the
weekend, KSLC could reach shy of 90F for the first time in over a
month. Temperatures will remain slightly cooler than average for
much of the remainder of the state.

&&

.AVIATION...KSLC...VFR conditions are expected through the valid
TAF period. Visibility will mostly remain above 6 sm, and smoke is
expected to lift north into the evening. Smoke will decrease more
Monday. Northwest winds are expected to switch to the southeast
around 04Z with largely clear skies.

Rest of Utah and southwest Wyoming...VFR conditions are expected
through the valid TAF period. Scattered showers and thunderstorms
are expected in southern Utah through 04Z with heavy rain and gusty
winds the main threat. Smoke will decrease in northern Utah in the
evening and for Monday. Scattered showers and thunderstorms capable
of heavy rain and gusty winds are expected Monday afternoon largely
south of KSLC.

&&

.FIRE WEATHER...Showers and thunderstorms have developed over
southern Utah in a most airmass as northern Utah remains hot, dry,
and stable. Repositioning of the ridge will result in southerly
flow developing over the area beginning tomorrow, allowing
moisture to spread across the entire district by Tuesday. Little
change in the pattern is anticipated for the middle to latter part
of the week, allowing unsettled conditions to continue.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flash Flood Watch until 10 PM MDT this evening for UTZ123>125.

WY...None.
&&

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

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

Hazardous Weather Outlook
National Weather Service Salt Lake City UT
618 AM MDT Sun Jul 25 2021

UTZ101>131-WYZ021-261300-
Great Salt Lake Desert and Mountains-Tooele and Rush Valleys-
Eastern Box Elder County-Northern Wasatch Front-Salt Lake Valley-
Utah Valley-Cache Valley/Utah Portion-Wasatch Back-
Bear Lake and Bear River Valley-Wasatch Mountains I-80 North-
Wasatch Mountains South of I-80-Western Uinta Mountains-
Wasatch Plateau/Book Cliffs-Western Uinta Basin-
Western Millard and Juab Counties-Eastern Juab/Millard Counties-
Central Mountains-Sanpete Valley-Sevier Valley-Castle Country-
San Rafael Swell-Southwest Utah-Lower Washington County-
Zion National Park-Southern Mountains-Upper Sevier River Valleys-
Bryce Canyon Country-South Central Utah-
Capitol Reef National Park and Vicinity-Western Canyonlands-
Glen Canyon Recreation Area/Lake Powell-Southwest Wyoming-
618 AM MDT Sun Jul 25 2021

This Hazardous Weather Outlook is for the western two thirds of
Utah and southwest Wyoming.

.DAY ONE...Today and Tonight

Showers and thunderstorms capable of producing heavy rain, gusty
winds, and hail will once again occur this afternoon and evening.
The strongest storms are expected across southwest Utah where a
potential for flash flooding exists, especially in prone areas
such as slot canyons, burn scars, areas of steep terrain, and
normally dry washes and streams.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Moisture will spread northward Monday into Tuesday. Daily showers
and thunderstorms capable of heavy rain, gusty winds and small
hail will occur each afternoon and evening across much of the
forecast area through the week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information
about observed severe weather to the NWS while following all
local, state, and CDC guidelines.

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

For information on potential road travel impacts visit...
http://www.udottraffic.utah.gov/roadweatherforecast.aspx

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
526 PM MDT SUN JUL 25 2021

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

0410 PM     TSTM WND GST     3 N CEDAR CITY          37.72N 113.07W
07/25/2021  M61 MPH          IRON               UT   MESONET

            MEASURED AT THE UDOT RWIS ALONG I-15 AT MP 62.5

&&

JW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
542 PM MDT SUN JUL 25 2021

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

0410 PM     TSTM WND DMG     1 W BEAVER              38.28N 112.66W
07/25/2021                   BEAVER             UT   LAW ENFORCEMENT

            TREE DOWN ON POWER LINE IN GREENVILLE SHORTLY AFTER 400
            P.M. REPORT RECEIVED FROM BEAVER COUNTY SHERIFF.

&&

JW

Special Weather Statement
National Weather Service Salt Lake City UT
544 PM MDT Sun Jul 25 2021

UTZ123-128-260015-
South Central Utah UT-Lower Washington County UT-
544 PM MDT Sun Jul 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN WASHINGTON COUNTY
UNTIL 615 PM MDT...

At 544 PM MDT, National Weather Service Doppler radar indicated a
strong thunderstorm near Sand Hollow State Park, or 17 miles west of
Colorado City...moving south at 10 mph.

Penny to nickel size hail and wind gusts up to 50 mph will be
possible.

Locations impacted include...
Apple Valley, Sand Hollow State Park and Rockville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If threatening weather approaches, take shelter in a sturdy building.

This storm may intensify, so be certain to monitor local radio and
available television stations for additional information and possible
warnings from the National Weather Service.

&&

LAT...LON 3700 11340 3711 11339 3712 11306 3700 11308
TIME...MOT...LOC 2344Z 356DEG 9KT 3707 11328

ND

Special Weather Statement
National Weather Service Salt Lake City UT
552 PM MDT Sun Jul 25 2021

UTZ123-125-260015-
Southern Mountains UT-Lower Washington County UT-
552 PM MDT Sun Jul 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL WASHINGTON COUNTY
UNTIL 615 PM MDT...

At 551 PM MDT, National Weather Service Doppler radar indicated a
strong thunderstorm 9 miles southeast of Beaver Dam...moving south at
10 mph.

Half inch hail and wind gusts up to 50 mph will be possible.

Locations impacted include...
Beaver Dam, Gunlock State Park, Motoqua, Gunlock, Goldstrike and
Veyo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If threatening weather approaches, take shelter in a sturdy building.

Heavy rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

This storm may intensify, so be certain to monitor local radio and
available television stations for additional information and possible
warnings from the National Weather Service.

&&

LAT...LON 3759 11405 3746 11378 3737 11371 3727 11371
      3728 11405
TIME...MOT...LOC 2351Z 356DEG 9KT 3745 11388

ND

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