Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 231049

Area Forecast Discussion
National Weather Service Salt Lake City UT
449 AM MDT MON MAY 23 2016

.SYNOPSIS...An elongated upper level trough stretching from southern
Canada to the California coast will maintain a mild southwest flow
over Utah early in the week. Cooler and more unsettled conditions
will return midweek as the trough shifts east through the Great


.SHORT TERM (Through 18Z Thursday)...A mean longwave trough remains
in place over the western CONUS this morning, with several embedded
shortwave disturbances evident on water vapor imagery. The first
such feature is currently over southern Nevada and will lift
northeast across Utah today. Some mid and high clouds have already
spread into Utah ahead of this trough, and a few weak showers are
evident on radar across northwest Utah. However, with a drier
southerly flow spreading across central Utah, showers and
thunderstorms today should remain confined to northern Utah with
less coverage than in the past few days. Otherwise, the airmass will
see a warming trend today although temperatures will remain a few
degrees below climatological normals across most areas.

After a bit of a lull in shower activity tonight, the next shortwave
disturbance, currently off the West Coast, will rotate into the area
tomorrow afternoon. This more energetic feature should bring a
slightly better chance of showers and thunderstorms to the area.

The third feature, currently just southwest of Vancouver Island,
will dive strongly south before swinging inland as a weak closed low
tomorrow night. This low will track across far northern Arizona and
could bring a small chance of showers to portions of southern Utah
Wednesday afternoon and evening. Meanwhile, another shortwave
disturbance is progged to rotate around the closed low currently
over southern Alberta/Saskatchewan and graze northern Utah. This
wave will help push a weak boundary into northern Utah which could
keep scattered showers in place across the northern and west-central
Utah Wednesday into Thursday morning.

.LONG TERM (After 18Z Thursday)...The bulk of the Pacific trough is
expected to exit to the east through the day Thursday, but enough
moisture and instability should be in place to keep showers going
through the afternoon. Some warming and drying is expected Friday,
as shortwave ridging builds over the Rockies between storm systems.

The next system coming out of the Pacific Northwest is a large
closed low that is forecast to dig into western Idaho starting
Friday night. However, confidence beyond that is very low for Utah
and southwest Wyoming. The GFS hangs this low back to the west,
keeping the forecast area relatively dry and warm through the
weekend, while the ECMWF insists on pushing a decent cold front into
northern Utah on Saturday. While there isn`t a huge difference in
the placement of this low in the models, the devil is in the
details, and that is what keeps the nature of the weekend and beyond
sketchy. For now, have raised POPs to place them closer to
climatological values, with no major changes to most other forecast
elements for days 5-7.


.AVIATION...Light and variable winds at the SLC terminal this
morning will eventually increase from the northwest, likely reaching
7 knots or higher between 17Z and 19Z. There is a 20 percent chance
of showers or thunderstorms impacting the terminal this afternoon,
but shower coverage across northern Utah should generally be less
than the last couple days.


.SLC Watches/Warnings/Advisories...



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