Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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314
FXUS65 KSLC 151654
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1054 AM MDT Fri Sep 15 2017

.SYNOPSIS...Cool and showery weather will continue across
northern and central Utah and southwest Wyoming today. A milder
southwesterly flow will return for the weekend. Another
unseasonably cold storm system will impact the forecast area next
week.

&&

.DISCUSSION...Morning water vapor satellite imagery has a very
nice baroclinic leaf signature developing across western Montana
and central Idaho on the backside of the upper low rotating into
western South Dakota and Nebraska. The cold front pushed through
northern Utah this morning, bringing breezy winds to areas and
areas of heavy rain under thunderstorms and rain showers. Areas
of urban flooding were reported with the heavier band of showers
that moved through along the Wasatch Front this morning. As the
upper level low swings through the intermountain west, expecting
the convective activity to come to an end across northern Utah
later this afternoon into evening, as dry air can be seen on
satellite wrapping in behind the low across Nevada.

Temperatures are changing quite a bit and will be seen in the
daytime highs today across the state. The 12z RAOB sounding had
700 mb temperature of +3C while just 24 hours ago the temperature
was +10C; so the feel of fall was definitely noted this morning.
Some snow dusting was observed at the higher peaks in the Wasatch,
with snow levels about 9500 - 10000 feet. Expecting the
temperature to continue to drop throughout the day today and
bottoming out this evening around -2C or so before a gradual
warming and drying trend will take place over the next 48 hours or
so with shortwave ridging building in. Made small updates to the
forecast this morning, but overall the going forecast is in good
shape.

&&

.AVIATION...Cold frontal passage at the KSLC terminal this
morning has shifted the winds to the northwest and remain in place
as of this writing. MVFR ceilings and visibilities should improve
to VFR by 19-20z as shower/thunderstorm activity moves east and
south of the terminal. The lightning threat should also come to an
end by this time as well. Cigs will likely remain around 7000
feet through the evening hours, and should lift above 7000 feet
after 06z.

&&

.FIRE WEATHER (Issued 402 am MDT)...
Most stations are now reporting an ERC at their 50th percentile
or lower, and the trend has been for decreasing ERC`s during the
past 3 days.

A stronger storm will cross the northern Rockies today, impacting
mainly northern and central Utah. A cold front is forecast to push
through the state by evening. Expect cool and unsettled
conditions especially north of Interstate 70. The stronger
activity may bring lightning, and locally gusty/erratic winds and
brief heavy downpour. The snow level will fall from 11kft this
morning to 9kft this evening.

Warming and drying occurs tomorrow through Monday ahead of the
next broad cold Pacific Northwest storm. Gusty winds both ahead of
and behind the cold front Tuesday, which may bring locally
critical fire weather conditions across the south if fuels can
sufficiently dry out. Cooling and moistening again for the middle
of next week.

&&

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

$$

Dewey

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visit...
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