Flash Flood Warning 25, NWS Salt Lake City, UT

171 
WGUS75 KSLC 152242
FFSSLC

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

UTC025-160030-
/O.CON.KSLC.FF.W.0025.000000T0000Z-180716T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
442 PM MDT SUN JUL 15 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM MDT FOR
CENTRAL KANE COUNTY...

At 440 PM MDT, heavy rainfall from afternoon thunderstorms fell over 
the Last Chance Creek, Warm Creek and Wahweap drainages.  Flash 
Flooding is expected in these areas through the terminus at Lake 
Powell.

Some locations that will experience flooding include...Big Water and 
the Last Chance, Warm and Wahweap Creeks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for flooding even in locations not receiving rain. Dry
washes, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.

&&

LAT...LON 3742 11149 3716 11130 3701 11158 3713 11176
      3734 11194

$$

CRK

185 
WGUS75 KSLC 160027
FFSSLC

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

UTC025-160036-
/O.EXP.KSLC.FF.W.0025.000000T0000Z-180716T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
627 PM MDT SUN JUL 15 2018

...THE FLASH FLOOD WARNING FOR CENTRAL KANE COUNTY WILL EXPIRE AT 630
PM MDT...

Enhanced runoff will continue across the Last Chance, Warm Creek and 
Wahweap drainages. Unimproved area roads and trails may be 
impassable or washed out. Use caution in this area. 


LAT...LON 3742 11149 3716 11130 3701 11158 3713 11176
      3734 11194

$$

CRK

Area Forecast Discussion
National Weather Service Salt Lake City UT
1024 AM MDT Sun Jul 15 2018

.SYNOPSIS...A drier northwest flow will develop across the area
today with moisture lingering across the south. A weak weather
system will brush by northern Utah Monday before high pressure
strengthens during the midweek period.

&&

.DISCUSSION...Primary focus moving forward today will key in on
the next round of anticipated convection focused from around
Dixie east-northeast across Glen Canyon/Escalante National
Recreation area (through this evening). Points north of there
continue to further dry/stabilize beneath a slight building of
heights in response to yesterday's wave passage and further
development of a mid level high circulation upstream over Nevada
(this impinging a drier northwesterly flow aloft across the
northern 2/3rds). A marked delineation exists between these areas
per latest analysis's, specifically regarding deep layer moisture
and instability potential, with axis extending roughly from the
Book Cliffs SW to the Cedar City area and points south.

With surface dewpoints remaining in the mid 50s to low 60s across
the far south, PWAT in excess of 1 inch, minimal inhibition, and
LCLs roughly 1500m (or so), the above mentioned areas remain
primed for efficient convective development once low level lapse
rates steepen across the elevated heat sources (southern mtns)
over the next few hours. Once formed, lack of flow and ample
boundary layer moisture should once again allow for outflow
dominated propagation off the terrain and potentially down
drainage across the Grand Staircase. Given the antecedent
conditions and instability potential there, opted to increase PoPs
across the southeast while adding locally heavy rain mention in
latest update. No other marked updates to note this morning.
Previous discussion below.

.PREVIOUS DISCUSSION...A weak shortwave trough expected to move
onshore across the Pacific Northwest tonight will slowly
translate eastward Monday, brushing by northern Utah late Monday
into Monday night. Convection expected to form across northeast
Nevada Monday will likely spread into northwest and north central
Utah later Monday afternoon through Monday night, and have
maintained a mention of thunderstorms for this area. Meanwhile
lingering moisture in the south will maintain a threat for
isolated thunderstorms primarily along the terrain.

In the wake of this wave mid level ridging is expected to begin
amplifying Tuesday. Associated subsidence along with continued
drying should keep any threat of convection isolated and confined
to the far south.

Temperatures in the northern valleys are expected to run in the
mid to upper 90s today through Tuesday, while the south will
likely experience a warming trend as the airmass gradually dries
out.

Behind the Tuesday shortwave trough, a drier airmass continues to
push into the northern two- thirds of Utah through early
Wednesday, keeping any convective activity confined to the far
southern portions of the state. Upper level ridging also amplifies
overhead through the day Wednesday, leading to a hot day area-
wide, with temperatures potentially approaching triple digits
across the northern valleys Wednesday afternoon.

The high continues to migrate eastward Thursday, generally setting
up over the Four Corners area for the end of the week and heading
into the weekend. This allows additional moisture to again return to
the area from the south starting Thursday, with the potential for
showers and thunderstorms spreading into much of the CWA. This
familiar weather pattern of very warm temperatures and
increasingly active convection currently looks to persist through
day 7 (Sunday).

&&

.AVIATION...VFR conditions will prevail at the SLC terminal through
the TAF period. Southeast winds are expected to shift to the NW at
about 19Z although there is a 30% chance that winds will shift by
18Z.

&&

.FIRE WEATHER...High pressure is expected to strengthen to the west
of the area today allowing for a drier northwest flow. Showers and
thunderstorms will remain possible across the south, although
coverage and intensity is expected to be less than what has been
observed over the past few days. A weak weather system is expected
to brush northern Utah late Monday through Monday night bringing a
chance of showers and thunderstorms. High pressure is expected to
strengthen midweek allowing for hot and generally dry conditions.

&&

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

DISCUSSION/AVIATION...Merrill/Struthwolf
PREVIOUS DISCUSSION...Seaman/Schoening

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