High Wind in Utah, June 11 to 12, 2017

Area Forecast Discussion
National Weather Service Salt Lake City UT
339 PM MDT Sun Jun 11 2017

.SYNOPSIS...Warm and dry conditions will continue through the
evening with strong southwesterly flow over the forecast area. A
cold upper low off the Pacific Northwest coast will move across
Utah and southwest Wyoming late tonight through Tuesday. The
region will see a steady warming trend beginning midweek.

&&

.SHORT TERM (Through 00Z Wednesday)...Winds have been slow to ramp
up so far today but the stronger winds aloft are just reaching the
western Utah border this afternoon and will move across the western
portions of CWA this evening and over the rest of the CWA overnight.
The moisture that got picked up ahead of this system is currently
showing up as some isolated showers over northern portion of the
central mountains and Uintas this afternoon. This will continue into
this evening.

The associated cold front will slowly move from southwest to
northeast across the CWA late tonight through Monday morning. Strong
winds aloft in the wake of this front will likely keep gusty surface
winds across western valleys Monday. Ahead of the cold front, strong
southwest winds will continue as well as across eastern and southern
portions of the CWA.

Temperatures will fall 20-25 degree behind this front across
northern Utah and 12-20 degrees across southern and eastern portions
of the CWA Monday. The cold air aloft works its way in across
northern Utah late Monday afternoon through Monday night and early
Tuesday. Scattered showers and isolated thunderstorms are expected
in the late afternoon and evening then transform to widespread rain
and snow in the mountains above 7500 Monday night into Tuesday.
Valleys from about Provo northward could see 0.05 to 0.20 of an inch
with higher amounts in the mountains. Accumulations in the northern
mountains could be as much as 2-5 inches above 8500 ft.

The cold unstable air mass moves east Tuesday afternoon which should
turn off all precip in most northern valleys but left some scattered
showers in the mountains as some moisture lingers and any sunshine
will help destabilize the air mass. The southern half of the CWA
will remain dry with temperatures warming already on Tuesday while
little change is expected across the north between Monday and
Tuesday.

&&

.LONG TERM (After 00Z Wednesday)...The cold trough is expected to
exit the forecast area by Tuesday evening. Behind it, a dry zonal
flow will develop. A series of shortwaves moving well north of the
area will keep the ridge from amplifying much through the work
week. However, Utah and southwest Wyoming will still see a steady
warming trend with maxes near seasonal normals on Wednesday and up
to 10F above those values by Thursday. EC/GFS indicate the ridge
amplifying over the Great Basin over the upcoming weekend,
resulting in additional warming.

&&

.AVIATION...Gusty southerly winds will continue at the KSLC terminal
through the night. Any cigs will remain above 7000 ft AGL.

&&

.FIRE WEATHER...Storm circulation moving into the western Great
Basin has an impressive broad dry slot evident on the water vapor
nosing into west central Utah at this time. This dry air along with
strong winds will combine to create critical fire conditions late
this afternoon and well into this evening with gusts over 60 mph
over the western valleys and over 40 mph elsewhere.

The associated cold air will filter into the region from the west
southwest overnight through the day Monday. There is very limited
moisture associated with system although a squirt of moisture ahead
of this system over central and eastern mountains has been enough
for isolated high based convection there late this afternoon and
evening. The core of the system will move over northern Utah Monday
night and this will be the best threat for showers and isolated
thunderstorms.

Dry air is expected to wrap around the southern portion of this
system and will bring RFW conditions again to the central and
western valleys as well as the eastern valleys for Monday. The winds
will be quite strong over southern portions of 478 but RHs will
probably not quite reach below 15% so have decided to keep FWX zone
478 out of a RFW at this time.

The north will remain cool on Tuesday but the south will warm by 5-
10 degrees with a decrease in the RH again. A warming and drying
trend will prevail through the rest of the week.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning until 10 PM MDT this evening for UTZ478-482-484-
     489-492-494-495-497-498.

     Red Flag Warning from 10 AM to 10 PM MDT Monday for UTZ482-484-
     489-494-498.

     Wind Advisory until midnight MDT tonight for UTZ002-006-010-
     012>014-020-021-517-518.

     Red Flag Warning from 9 AM to 9 PM MDT Monday for UTZ492-495.

     High Wind Warning until midnight MDT tonight for UTZ003>005-015-
     016-019.

WY...None.
&&

SHORT TERM/FIRE WEATHER...Struthwolf
LONG TERM...Traphagan
AVIATION...Wilensky

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
344 PM MDT Sun Jun 11 2017

UTZ001>016-019>021-517-518-WYZ021-120945-
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-
344 PM MDT Sun Jun 11 2017

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

.DAY ONE...This Afternoon and Tonight

High elevation snowmelt will continue to cause swift, high and
very cold flows along the waterways of northern Utah and
southwest Wyoming. Avoid areas adjacent to waterways that are fed
by high elevation snowmelt. These fast and cold waterways are
deadly, as a person or pet can drown in less than a minute if
they fall in.

Strong south winds are expected to continue to increase through
this evening. The strongest winds will gust in excess of 60 mph
at times across the western valleys and in the mountains. The
winds will continue to combine with low humidity to create
critical fire weather conditions across most valley locations
where fuels are critically dry.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Waterways of northern Utah and southwest Wyoming will continue to
be dangerous with high flows expected through the upcoming week.

An unseasonably cool low pressure system will cross the area
early Monday through Tuesday. Temperatures are expected to be
dramatically cooler by Monday, running as much as 10 to 15 degrees
below seasonal normals across the outlook area. Scattered showers
and thunderstorms will also be possible with this system Monday
afternoon and evening across northern portions of the outlook
area, with valley rain and mountain snow above 7500 feet expected
Monday night into Tuesday morning.

Gusty winds continuing Monday across the central and southern
valleys coupled with low humidity and dry fuels will result in
critical fire weather conditions again Monday afternoon and
evening.

.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