Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 261647
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1047 AM MDT Fri May 26 2017

.SYNOPSIS...An upper trough will move across the area today. A
cool northerly flow will follow for Saturday. A warming trend
starts Sunday and continues into mid week.

&&

.DISCUSSION...MSAS mslp analysis places a surface cold front over
central Utah with position just south of Delta. Morning water
vapor and H5 analysis place the parent trough over east- central
Idaho, with track taking a trajectory slightly SE towards far
northern Utah. Isolated to widely scattered showers continue to
remain focused along zone of best mid level baroclinicity over NE
Utah and SW Wyoming attm.

Vertical profiles lack much support for convection this morning,
with shower development largely driven by weak synoptic
forcing currently. Diurnal destabilization will aid to steepen
lapse rates across the north slightly this afternoon, especially
along the UT/ID border where mid level CAA will be most
pronounced, but as a whole instability will remain subtle at best.
As such, any additional precip is expected to be light. Moving
forward into the pm hours guidance suggests additional development
will be focused over SW Wyoming beneath the best diffluence
aloft, and along the UT/ID border closer to the cold core.
Isolated convection remains possible in the post frontal
environment from the central Wasatch Front south to the mtns of
central Utah with heating, but dry condions are expected to
prevail. Updated grids to decrease PoPs from the central Wasatch
Front and points south, and raised PoPs along the UT/ID border and
SW Wyoming to follow this thinking.

Overnight the front will continue to push south into southern Utah
prior to exiting the forecast area during the day Saturday. With
loss of upper support this front will be trending more frontolytic
in nature in 24 hours time, with potential for only weak forcing.
This said, Isolated to widely scattered showers will remain
possible across central/southern portions with passage, but precip
is expected to remain minimal.

PREVIOUS LONG RANGE (After 18z Sunday...High pressure is expected
to move back over the area beginning Sunday. With a bit of
residual moisture in place (particularly in the GFS solution)
there is the possibility of a few showers/storms over the higher
terrain of northern Utah Sunday and Monday. However, the vast
majority of the forecast area should remain dry with steadily
warming temperatures. Maxes should be in excess of 5F above
seasonal norms by Memorial Day, climbing further for Tuesday and
Wednesday.

Latest GFS continues to indicate a weakening of the ridge that
allows moisture to be drawn northward into the forecast area. By
Tuesday it indicates PWs in the 0.5 to 0.7 inch range moving into
southern Utah before gradually spreading northward Tuesday into
Wednesday. It then brings a weakening trough across the forecast
area Thursday into Friday, adding to the instability. Meanwhile,
the EC is still showing a much drier solution, with the ridge
remaining strong through Tuesday before weakening Tuesday
night/Wednesday as a grazing trough moves by. EC has been more
consistent to this point, so have leaned toward the drier
solution, but have kept in some isolated POPs to account for the
GFS solution.

&&

.AVIATION...There is a 30 percent chance of showers/thunderstorms
impacting the terminal through today, with gusty erratic winds as
the most likely impact. Away from showers, northwesterly winds
should prevail, with a 40 percent chance of gusts 30 mph or greater
between 15Z and 22Z.

&&

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

$$

DISCUSSION/AVIATION...Merrill/Schoening
PREVIOUS LONG TERM...Traphagan

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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