Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 262155
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
355 PM MDT Thu Apr 26 2018

.SYNOPSIS...High pressure will bring very warm temperatures to the
area through Friday. A low pressure system over the eastern
Pacific will move east into the Great Basin Sunday, then track
slowly through the region early next week.

&&

.SHORT TERM (Through 00Z Monday...Ridge of high pressure
developing over the western Great Basin today will drift eastward
overnight and be overhead Friday. Some mid-level moisture will
come along with this ridge and bring a slight chance of high based
showers or thunderstorms to the mountains late Friday afternoon
and evening. The main threat here will be gusty outflow winds as
the moisture is confined to the mid and high levels of the
atmosphere.

The ridge will slide farther east Saturday due to a trough moving
in from the Pacific. South winds will increase ahead of this
trough to 15-25 mph over the western valleys. The associated cold
front will arrive late Saturday afternoon over extreme northwest
Utah and into the central Wasatch by mid Saturday evening.
Scattered showers and isolated thunderstorms will occur ahead and
with the cold front passage across northern Utah, but this front
is expected to weaken as it moves into eastern and southern Utah
by Sunday as the dynamic support aloft moves northeast into
Wyoming. Therefore, little if any threat of showers or
thunderstorms over the southern half of the CWA.

Temperatures in general will be 15-20 degrees above normal Friday
and Saturday which means these temps will be record challenging.
Temperatures will cool back to near normal across the western
valleys and northern Utah and southwest Wyoming by Sunday.
However, the southeastern portions of the CWA will continue to
have temperatures several degrees above normal on Sunday.

The cold pocket aloft will brush by northern portions of the CWA
Sunday bringing a threat of showers and isolated thunderstorms
while the southern two-thirds of the forecast area should remain
dry.


.LONG TERM (After 00Z Monday)...The large Pacific low continues to
encroach on Utah and southwest Wyoming Sunday night, with another
round of low level cold advection pushing into the northern half of
the CWA through the night and into Monday morning. This low level
forcing, combined with another mid-level vort lobe swinging over the
area, should combine to increase the coverage of precipitation
across the area through the day Monday. Have generally increased
POPs and decreased temperatures through this period of time, and
this first good initial push could be the best period of
precipitation for northern Utah associated with the longwave trough
over the west.

Once this initial wave exits to the east Monday night, the next
round of decent, well-organized forcing looks to come with a
shortwave dropping down the west coast Monday night, then swinging
across the Desert Southwest Tuesday into Wednesday. This could focus
the best precipitation across the southern half of Utah, but in
general can`t rule out showers anywhere in the CWA through the first
half of the week, as enough moisture and instability looks to linger
for stray showers here and there.

The weather pattern becomes considerably drier and more stable by
the end of the work week, as the longwave trough shifts to the east
and a ridge builds over the west. There is still some discrepancy
about whether this starts Thursday or Friday, but either way a
warming trend looks likely heading into next weekend....

&&

.AVIATION...The SLC terminal will see VFR conditions overnight with
no aviation impacts to the terminal. Northerly winds in place,
although light, are expected to switch to the southeast between 03z-
04z.

&&

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

$$

SHORT TERM...Struthwolf
LONG TERM...Schoening
AVIATION...Dewey

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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