Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 162137
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
337 PM MDT Fri Jun 16 2017

.SYNOPSIS...A cold front will make its way across much of the
forecast area tonight and into Saturday. High pressure will
strengthen over the West early next week, resulting in hot
temperatures across the forecast area.

&&

.SHORT TERM (Through 06z Tuesday)...The forecast area is under a
westerly flow this afternoon. Conditions are clear over southern
Utah with a dry airmass in place. Satellite derived PWs indicate
values in the 0.2 to 0.4 inch range. Meanwhile, clouds are
increasing over northern Utah and southwest Wyoming as a trough
moves just north of the area. This trough will bring a cold front
through northern Utah tonight and into central and part of southern
Utah tomorrow. Passage of this front will be generally dry, but
satellite derived PWs show values in the 0.8 to 1.0 inch range over
northern Utah, which would be enough for some showers near the UT/ID
border.

The front will bring noticeable cooling tomorrow over northern Utah
and southwest Wyoming, with maxes running 5-7F below values observed
today, pretty close to seasonal normals, with southern Utah seeing
slight warming compared to yesterday. Northern Utah temperatures
will rebound Sunday while southern Utah cools just slightly with the
influence of the front.

The axis of a large ridge currently over the Pacific will move over
California by Saturday night, allowing the ridge to amplify and
build over the entire West beginning early next week. This will
result in hot and generally dry conditions across the forecast area,
with the potential for dangerously hot, record challenging
temperatures over southern Utah.

.LONG TERM (After 06z Tuesday)...The strong high pressure
positioned across the Desert Southwest bringing dangerously hot
temperatures to southern Utah, and hot temperatures state-wide,
continues through mid to late week. By Wednesday, the ridge begins
to flatten out and slowly sink south and east. Models are hinting
at a slight nudge of moisture into central and eastern Utah mid to
late week which may lead to potential for afternoon showers and
convection along and near the higher terrain. Kept mention of PoPs
though lowered values a tad bit with the latest guidance not
being overly excited about this under high pressure.

By Friday of next week, another shortwave is progged to brush by
to the north of Utah, helping to weaken the ridge further and
bring back a more zonal flow pattern. Models are in pretty good
agreement with this patter until Saturday before diverging on
solutions. Bottom line is that hot and mostly dry weather looks to
prevail for most of next week, with record high temperatures being
challenged across southern Utah through the first part of the
week.

&&

.FIRE WEATHER...A cold front will make its way across northern
Utah tonight and into central and parts of southern Utah tomorrow.
With a bit of moisture pooled over northern Utah, thunderstorms
are possible through this evening, primarily near the UT/ID
border. Behind the boundary on Saturday, temperatures will be near
seasonal normals over northern Utah but noticeably warmer than
that across central and southern Utah.

Strong high pressure will build over the West beginning Sunday,
resulting in very warm temperatures, particularly over southern
Utah with near record highs anticipated. These hot temperatures
combined with the dry conditions will likely result in Haines
Index values of six Monday through Wednesday. Moisture will
gradually increase across the area early next week, with a few
high based storms over the higher terrain possible beginning
Tuesday.

&&

.AVIATION...Northwest winds will continue through this evening with
winds shifting to the southeast between 02Z and 04Z. A dry cold
front located over the north end of the Great Salt Lake is expected
to reach the KSLC terminal between 07Z and 09Z, shifting the winds
back out of the northwest. There is a 20 percent chance of the
switch back to northwest winds occurring after 09Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Excessive Heat Watch from Monday afternoon through Thursday
     evening for UTZ013-019>021.

WY...None.
&&

$$

SHORT TERM...Traphagan
LONG TERM...Dewey
AVIATION...Lukinbeal

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



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