Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 171641
Area Forecast Discussion
National Weather Service Salt Lake City UT
941 AM MST Fri Feb 17 2017
.SYNOPSIS...The upper level trough off the California coast will
send moisture along with a series of weather disturbances across
Utah through the weekend. High pressure aloft will return early
next week, followed by another round of active weather midweek.
.DISCUSSION...The broad trough off the California coast is
resulting in increasing southerly flow over the forecast area this
morning. This flow has moved a rather moist airmass into southern
Utah, with PWs in the 0.5 to 0.6 inch range, close to the maximum
observed this time of year. This moisture combined with an
ejecting wave out ahead of the main trough is resulting in
increasing coverage of precipitation over southern Utah.
The moisture will continue to spread northward today, with those
PW values around 0.5 inch becoming widespread across Utah and
southwest Wyoming by late this afternoon. The shortwave energy
will shift northward during this time, and so will the focus of
precipitation. Airmass is relative warm with 700 mb temps in the
-2C to -4C range, so snow levels will be on the high side, around
7000 feet for many locations. As a result, only the highest
elevations have the potential to see snow-related impacts.
The very moist airmass will remain over the forecast area over the
next several days as the California trough tracks slowly eastward.
Additional weak shortwave energy will combine with the moisture to
keep at least some precip going over the state, particularly over
central and southern Utah. The main trough is on track to cross
the Desert Southwest Saturday night into Sunday, and coverage of
precip will increase due to the additional instability it
provides. High pressure is expected to move in briefly behind the
exiting system, but an active pattern will continue through next
No updates expected to the forecast this morning.
.AVIATION...Light and variable winds at the SLC terminal as of 16Z
should become steady out of the south around 17-20Z, though
increasing showers after 21Z could potentially produce briefly
erratic winds. Ceilings will lower through the day, with cigs below
7000 feet likely to develop between 20Z and 22Z. There is a 30
percent chance of MVFR conditions in rain showers from 22Z to 03Z.
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