Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 202210
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
410 PM MDT Thu Apr 20 2017

.SYNOPSIS...The upper level trough moving east across Utah will
generate numerous showers along with isolated thunderstorms
tonight. An upper level ridge trailing the trough will build into
the region this weekend, bringing a warming trend to the entire
state.

&&

.SHORT TERM (Until 00z Monday)...The axis of the negative-tilt
upper trough is now moving into extreme western Utah late this
afternoon. Good baroclinic structure exists with this feature with
good low-level cold advection tilting back the mid-level cold air
to the west, solid dynamic lift with the trough and fairly strong
upper divergence in the left exit region of the upper jet on the
back side of the trough. The best synoptic-scale lift will exist
this evening, with numerous showers and isolated thunderstorms the
result.

Trailing this trough a deep layer northwest flow cold advection
pattern will persist across northern Utah through late tonight.
This thermally driven lift along with orographic enhancement
should keep accumulating snows going along the Wasatch and
western Uinta ranges. Shallow instability continuing into Friday
morning should keep some light snow going across the central
Wasatch range and adjacent foothills. New accumulations should be
minimal as the remaining showers wind down during the mid to late
morning hours.

Building heights Friday night/Saturday will beginning a warming
trend as an upper ridge moves east across the state during the
first half of the weekend. The ridge axis will remain
progressive, passing to the eats of Utah late Saturday night.
Increasing southwest flow aloft on the back side of the ridge
will keep temperatures on the warm side, but also bring moisture
and the beginning of a new series of shortwaves on Sunday. The
initial shortwave early Sunday will offer little in the way of
precip. The second shortwave looks to be more energetic, though
the main impact may be after the end of the short term period on
Sunday evening.

.LONG TERM (After 00Z Monday)...The southern end of the broad trough
pushes through the area in earnest Sunday evening, before quickly
exiting to the east. Have increased POPs a bit for Sunday evening,
but precipitation totals should remain pretty low, as the wave is
generally a bit of a brush-by.

Any break between this first shortwave and the next one currently
looks to be less than 24 hours, with the next cold front moving into
northern Utah Monday afternoon/evening. While there are still some
differences in global models concerning the timing of various waves,
the big picture is that an extended period of moist, west-
northwesterly flow is expected late Monday through at least
Thursday. This means most of the work week will be seasonably cool
and wet across the northern half of the CWA, with precipitation
sometimes working down into southern Utah as well. Have kept fairly
aggressive POPs in the extended, as well as temperatures at or below
climatology through the week.

&&

.AVIATION...Winds at the SLC terminal will continue to be gusty
through at least 01Z, with occasionally erratic directions due to
nearby shower activity. MVFR conditions are possible in the heavier
showers, and there is also a chance of lightning at the terminal,
primarily between 22Z and 03Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 9 PM this evening to 11 AM MDT Friday for
     UTZ012-013.

WY...None.
&&

$$

SHORT TERM...CONGER
LONG TERM/AVIATION...SCHOENING

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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