Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 280251

Area Forecast Discussion
National Weather Service Salt Lake City UT
851 PM MDT Sun Sep 27 2020

.SYNOPSIS...Northerly flow aloft on the eastern periphery of a
ridge will maintain largely clear and dry conditions across the
forecast area. High pressure building over the region will result
in a gradual warming trend through the middle of the week, with a
dry forecast expected to be maintained through the week.


.SHORT TERM (Through 12Z Wednesday)...Strong high pressure aloft
along the west coast this evening will expand east during the
first half of the week. This feature will effectively block any
precipitation and produce a warming trend with readings above
normal across the forecast area by midweek.

Any weather concerns will occur tonight through early Monday.
For tonight, overnight low temperatures are likely to drop below
freezing through much of the Cache Valley, Sanpete Valley, and
many higher elevation valley areas along the Wasatch Back tonight.
Areas of patchy frost will be possible.

Across extreme southwest Utah a favorable northeast surface
pressure gradient with weak, but supportive, low level cold
advection will maintain gap winds across Washington county
overnight into early Monday morning. Both the cold advection and
favorable surface pattern should weaken considerably by around
mid-morning on Monday.

.LONG TERM (After 12Z Wednesday)...The extended forecast discussion
could probably be copy/pasted each day for the next week: dry and
warm with a stubborn ridge over the Western US.

Looking at the WPC Cluster Tool to summarize ensemble members, one
has to look to the 8-10 day forecast period to find even a hint of a
change, and even that is 1) only a flattening of the ridge and 2)
only predicted by a handful of the hundred ensemble members
available from the GEFS/EPS/GEM. This means we have very high
confidence in the continued dry and warm forecast. Temperatures are
forecast to run around 10 degrees above normal.


.AVIATION...North winds will work around to an east or southeast
direction and remain light through Monday morning. VFR conditions
will prevail at KSLC through the current TAF period.


.FIRE WEATHER...A cool northwesterly flow will persist across the
area through tonight. Gusty gap winds will persist across portions
of Washington County overnight into Monday morning. A cool and
stable airmass will remain in place Monday. High pressure aloft
will become established across the region beginning Tuesday,
bringing a warming trend along with continued dry conditions
through the remainder of the week. This ridge will also result in
light winds generally driven by diurnal slope flows.


UT...Red Flag Warning until 9 AM MDT Monday for UTZ497.




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