Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 212159
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
359 PM MDT Sat Apr 21 2018

.SYNOPSIS...High pressure aloft will maintain warm and dry
conditions across Utah through the day Sunday. A weak weather
disturbance will bring showers to northern Utah and southwest
Wyoming early in the upcoming week.

&&

.SHORT TERM (Until 00z Wednesday)...The weak diffluent westerly
flow aloft across the Great Basin will maintain dry conditions and
bring somewhat warmer temps to the forecast area on Sunday. A
shortwave moving into the Pacific Northwest early Sunday will
continue slowly east across the northern Rockies/northern Great
Basin late Sunday night through early Tuesday.

The initial push of the mid-level trough into northwest Utah
should bring convection to northern Utah through Monday morning.
Modest, but fairly deep cold advection along with dynamic support
from the upper trough and adequate moisture should be sufficient
to generate scattered convective precip. Increase jet support
during the day Monday could lead to a thunderstorm or two late
Monday morning through the afternoon.

Both the GFS and ECMWF are showing the development of a mid-level
circulation center within the the trough across the northern
Rockies late Monday afternoon or evening. The result of this
development will lead to a cyclonic northwest flow across far
northern Utah/southwest Wyoming late Monday night through Tuesday.
Any precip will likely stay close to the colder air aloft which
will remain primarily over southwest Wyoming. Rapid warming aloft
Tuesday afternoon should bring an end to any lingering showers up
north during the afternoon.

Will have to keep an eye on possible isolated convection over the
higher terrain of central/southern Utah Tuesday. The global models
do show a narrow band of moisture concentrated along the old low-
level baroclinic zone stalled out over the southern half of the
state. Anticipating just isolated coverage of any convection that
develops, and then mainly over the higher terrain through early
evening.

.LONG TERM (After 00z Wednesday)...An offshore low remains out to
sea by mid-week with high pressure ridging developing and continuing
across the eastern Great Basin. Dry and warming conditions will
settle in and persist for the forecast area of Utah and southwest
Wyoming for Wednesday.

Models begin to differ in a solution for Thursday, with a
brush-by trough sweeping through Wyoming and down the Front Range of
Colorado as one model suggests. The cold air looks to remain well to
the east of our area, so kept very minor mention of any
precipitation confined to that area. Heights and upper level
temperatures still remain warm, so went with a warm bias on the
temperature forecast for Friday and Saturday.

Heading into the weekend, went with some slight chance mention in
the mountains and higher terrain of northeast Utah and the central
spine mountains as the upper level low begins an inland trajectory
with increasing southwest flow. Confidence is still somewhat low
with this feature, being the far extended time period and given the
lack on consistent solutions.

&&






.AVIATION...Winds at the SLC terminal are expected to switch to the
southeast between 02-03Z.

&&

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

$$

SHORT TERM...CONGER
LONG TERM...DEWEY
AVIATION...KRUSE

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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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