Flash Flood Warning 61, NWS Salt Lake City, UT

171 
WGUS75 KSLC 221113
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
513 AM MDT WED AUG 22 2018

UTC025-053-221245-
/O.CON.KSLC.FF.W.0061.000000T0000Z-180822T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-Kane UT-
513 AM MDT WED AUG 22 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 AM MDT FOR
SOUTHEASTERN WASHINGTON AND WEST CENTRAL KANE COUNTIES...

At 512 AM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. One to two inches of rain has already 
fallen. This is likely resulting in flash flooding.

Some locations that will experience flooding include...
La Verkin, Zion National Park, Toquerville, Virgin, Springdale and
Rockville.

Additional rainfall is expected through sunrise.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3700 11319 3721 11320 3726 11330 3738 11324
      3747 11321 3747 11314 3738 11286 3714 11285
      3700 11310

$$

10

944 
WGUS75 KSLC 221251
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
651 AM MDT WED AUG 22 2018

UTC025-053-221301-
/O.EXP.KSLC.FF.W.0061.000000T0000Z-180822T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-Kane UT-
651 AM MDT WED AUG 22 2018

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN WASHINGTON AND WEST
CENTRAL KANE COUNTIES HAS EXPIRED...

The heaviest of rainfall has diminished for the time being across 
Washington and Kane counties. Be on guard for areas of flooding that 
have yet to recede. Additional rainfall is expected through the day.

LAT...LON 3700 11319 3721 11320 3726 11330 3738 11324
      3747 11321 3747 11314 3738 11286 3714 11285
      3700 11310

$$

10

Area Forecast Discussion
National Weather Service Salt Lake City UT
841 PM MDT Tue Aug 21 2018

.SYNOPSIS...Showers and thunderstorms will continue in monsoonal
moisture tonight and tomorrow, bringing some locally heavy
rainfall, especially over central and southern Utah. High
pressure will bring a drying and warming trend beginning Thursday.

&&

.DISCUSSION...A positively tilted trough extending from the
northern Great Basin into the northern Rockies, coupled with a mid
level ridge centered over the southern Great Plains, is resulting
in a southwesterly flow across the forecast area. This is helping
advect monsoonal moisture northward across much of the forecast
area, and allowed for an active convective day. Deep layer shear
supported strong updrafts with produced hail in addition to
locally heavy rainfall. Much of this activity has been on the
decline over the past few hours across southern and eastern Utah,
however the models have been insistent scattered showers and
isolated thunderstorms will persist into the overnight hours
across these areas. Meanwhile northern Utah became active this
evening as outflow gradually worked its way northward into a
marginally unstable airmass. This activity has been weakening and
shifting northeast over the past 30-60 minutes or so. Updated
earlier to drop going Flash Flood Watch as heavy rain threat had
abated, as well as adjusted PoPs based on ongoing convective
trends.

The upstream trough is expected to slowly work its way eastward
during the day Wednesday. With moisture remaining in place should
see another active day with deep layer shear supporting organized
convection, with gradual drying working its way into western Utah
as the afternoon progresses. As this wave passes east of the area
Wednesday night drier air and subsidence will allow for a dry end
of the work week.

&&

.AVIATION...Showers and thunderstorms may impact the KSLC
terminal through at least 04Z, and possibly into the overnight
hours, bringing the potential for lightning and brief MVFR
visibilities in heavier rain. Winds will remain predominantly from
the south, but could become gusty and erratic near storms through
the remainder of the evening.

&&

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

Seaman

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
358 AM MDT Tue Aug 21 2018

UTZ001>016-019>021-517-518-WYZ021-221300-
Cache Valley/Utah Portion-Northern Wasatch Front-
Salt Lake and Tooele Valleys-Southern Wasatch Front-
Great Salt Lake Desert and Mountains-Wasatch Mountain Valleys-
Wasatch Mountains I-80 North-Wasatch Mountains South of I-80-
Western Uinta Mountains-Wasatch Plateau/Book Cliffs-
Western Uinta Basin-Castle Country-San Rafael Swell-
Sanpete/Sevier Valleys-West Central Utah-Southwest Utah-
Utahs Dixie and Zion National Park-South Central Utah-
Glen Canyon Recreation Area/Lake Powell-Central Mountains-
Southern Mountains-Southwest Wyoming-
358 AM MDT Tue Aug 21 2018

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

.DAY ONE...Today and Tonight

Widespread showers and thunderstorms will bring a risk of flash
flooding near burn scars, slick rock, slot canyons and normally
dry washes.

Smoke will continue to affect northern Utah.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Moisture remains in place Wednesday which may lead to another
round of heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

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