Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 182154
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
354 PM MDT Fri May 18 2018

.SYNOPSIS...A weak ridge will move over the Great Basin Saturday
but another trough will move to central California by Sunday. A
southerly flow will prevail Sunday through Wednesday as this low
then tracks north northeast across Nevada into Idaho.

&&

.SHORT TERM (Through 00Z Tuesday)...The weak upper low will move
into Wyoming late tonight but remain close enough to Utah to keep
unsettled weather continuing over especially northeast and
southwest Wyoming through Saturday. A weak lobe of energy rotating
around the southeast portion of the low will set off showers and
thunderstorms over northeast Utah this evening before dying off
after sunset. Another shortwave feature moving southeast across
east central Nevada is expected to bring some scattered showers
and isolated thunderstorms to southwest Utah this evening.
However, the air mass at low levels is rather dry so most valleys
may experience more wind than rain.

Enough moisture is expected to remain in place through the weekend
to keep mainly mountain showers and thunderstorms while the
valleys will see mainly dry conditions with isolated threat of
showers.

The upper low over California on Monday will increase the
southerly flow aloft which will dry out the southern half of the
forecast area. However. diffluence aloft over northern Utah and
southwest Wyoming will initiate showers and thunderstorms there.

.LONG TERM (After 00z Tuesday)...The upper level trough continues to
dig into southern California under warm southerly flow aloft. The
unsettled pattern continues into next week as the low circulates
through the Great Basin. Tuesday afternoon looks good in the way of
storm activity across mainly central and northern Utah and can not
rule out southern Utah. Diffluence aloft with some instability
present should be sufficient to initiate storms. However, as the
airmass continues to evolve with the low ejecting north and east
through the week, conditions look to become more stable.

By Wednesday, models diverge on solutions with timing of the wave
ejecting the area and how quickly the next low pressure system moves
in from the Pacific. The big picture has a train of troughs swinging
through the Western CONUS through the extended period, so kept
slight chance to chance mention of showers/storms through the
extended.

&&

.AVIATION...A 20 percent chance exists that showers and isolated
storms in the vicinity of the KSLC terminal currently will impact
the airfield through 04z this evening. If so, gusty/erratic winds
would be the primary operational concern. Outside of this, northerly
winds will persist through the evening prior to switching to the
southeast between 04-06z.

&&

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

$$

SHORT TERM...Struthwolf
LONG TERM...Dewey
AVIATION...Merrill

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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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