Flash Flood Warning 26, NWS Salt Lake City, UT

077 
WGUS75 KSLC 152240
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
440 PM MDT SUN JUL 15 2018

UTC053-152244-
/O.CAN.KSLC.FF.W.0026.000000T0000Z-180716T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
440 PM MDT SUN JUL 15 2018

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN WASHINGTON COUNTY IS
CANCELLED...

The heavy rain has ended across the Hildale and Colorado City areas. 
Flooding is no longer expected to pose a threat. Please continue to 
heed any remaining road closures.

LAT...LON 3701 11299 3701 11295 3700 11295 3700 11299

$$

CRK

Area Forecast Discussion
National Weather Service Salt Lake City UT
344 PM MDT Sun Jul 15 2018

.SYNOPSIS...Drier conditions will push into the south later
tonight into tomorrow. A weak weather system will brush by
northern Utah Monday before high pressure strengthens during the
midweek period.

&&

.SHORT TERM (Through 12z Wednesday)...Afternoon water vapor and H5
analysis depict the dominating ridge re-orienting more west over
the last 12 hours, with axis roughly from extreme northwestern
Utah SW across Socal. The ridge has further retrograded in
response to a northern branch short wave turning inland into the
NorCal region which has allowed a drier northwesterly flow to
intrude deeper south across the area, with the focused deep
moisture discontinuity now confined to extreme southwestern Utah
northeast across the Grand Staircase in southeastern Utah.

South and east of this moisture axis deep convection once again
formed over the southern mountains midday, with propagation trends
thereafter phasing down into the lower elevations forming
congealed clusters along the ensuing outflow boundaries. Down
drainage propagation of a few of these clusters prompted flash
flood warnings due to both the track and efficiency of rainfall, a
threat that will remain well into the evening from roughly Dixie
east across Grand Staircase/Escalante regions. A continuation of
northwesterly flow associated by the both the building high and
the approach of the northern branch short wave will finally allow
for more notable drying across the south/southeast come Monday.

Focus thereafter shifts back up to the north later Monday into
Tuesday as the northern branch short wave continues a near
easterly track into the northern Great Basin region at that time.
Although trending low amplitude and progged to phase down a bit
with inland translation, weak vorticity advection coupled a
somewhat favorable 50-60kt upper jet should create sufficient
enough lift to spark scattered convection across the far north
late day into the overnight hours (coverage potential greatest in
the evening along the UT/ID border). Not expecting too much
rainfall from these cells (fast motion), but likely to see some
gusty outflow boundaries forming across the northwest into the
overnight hours. Isolated convection should spread southeast along
the Wasatch Front and mtns overnight, lingering near the Uintas
late night.

By Tuesday morning this northern branch wave will be phasing
downstream of the area, and coupled with building heights in wake
much of the area will trend quite subsident and increasingly
stable. Can not rule out isolated and shallow mtn convection late
day, but as a whole dry, hot, and stable conditions should
dominate.

.LONG TERM (After 12Z Wednesday)...The global models are
pretty much in agreement through the extended period. The EC is a
little farther southeast with the 500mb ridge Friday through Sunday,
which appears to keep the 700mb temps a couple of degrees C cooler
than the GFS across the CWA. However, as far as the monsoonal flow,
both indicate the moisture will be on the increase from Friday
afternoon forward. Current PoP forecasts looked reasonable so
decided to let them ride for the time being.

Temperatures will likely be above normal through this period with
the strong ridge nearby. The hottest day should be Wednesday ahead
of the moisture moving northward. However, any day from Thursday
through Saturday could be just as hot depending on the amount of
cloud cover. Therefore the guidance from Superblend looked
reasonable.

&&

.AVIATION...VFR conditions to continue at the SLC terminal this
evening into tomorrow. Thunderstorm activity will be limited to
areas well south and west of the terminal. Northwest winds will
shift to southeast 03Z-04Z.

&&

.FIRE WEATHER...Scattered storms with locally heavy rain remain
across southeastern Utah this afternoon, but as a whole the
drying trend is continuing to push south across much of the area
today. These storms will exist into the evening hours prior to
dissipating for the overnight hours. Focus shifts to a progressive
upper level wave tracking in from the Pacific that will translate
across southern Idaho Monday into the overnight hours. Northern
portions of zone 478 and 479 have the greatest potential for
widely scattered thunderstorms Monday evening, with limited
rainfall potential. Due to the progressive nature of this wave,
these storms are expected to be relatively fast moving and mixed
mode between wet/dry, with gusty outflow boundaries possible for a
few hours after the storms pass. There is a slight chance the
track of this wave will focus more of the activity just north into
Idaho, but at this time the potential exists for new lightning
starts and gusty winds in wake for those zones. High pressure is
expected to strengthen midweek allowing for hot and generally dry
conditions across the district.

&&

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

Merrill/Struthwolf/Van Cleave

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http://weather.gov/saltlakecity/general/afd_faqs.php