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fxus65 kslc 260200 
afdslc

Area forecast discussion
National Weather Service Salt Lake City Utah
800 PM MDT sun Aug 25 2019

Synopsis...
a dry cold front will continue to move through the state through
this evening. Relatively tranquil weather can be expected through
Tuesday. Moisture may return Tuesday and Wednesday to Utah.

&&

Discussion...
going forecast in good shape, with dry northwest flow prevailing.
The cold front is currently across central Utah, and is expected
to near the southern Utah border by tomorrow morning.

Updated to freshen up the forecast with latest observational and
model data.

&&

Previous discussion...
a weak cold front is currently located across central Utah. This
cold front will continue to cross the state through this evening.
Expect temperatures to fall appreciably tomorrow...around 10
degrees or so for many locations.

Given continued cold air advection through the day Monday...expect
downslope areas such at the western Uinta Basin and Castle country
to remain gusty into Monday evening. See the fire weather
discussion for more information on red flag warnings in these
areas.

Heights will gradually rise across the state early this week. The
remnants of Tropical Depression Ivo will combine with a
relatively weak trough crossing into the Great Basin Wednesday.
This will likely bring an increased threat of convection to the
state...across southern Utah as early as Wednesday. This feature
is discussed in greater detail in the long term discussion.

An elongated ridge axis will be oriented southeast-northwest across the Great
Basin/eastern Pacific regions to begin the long term period, with
a plume of deep layer moisture oriented along and south of this
axis. A fair bit of this deep layer moisture will remain tied
closely to and advect northward coincident with remnant energy of
what is now Post- tropical cyclone Ivo off the northern Baja
Coast. Evolution of both the aforementioned ridge axis and
especially the Ivo remnants remain the focused forecast challenge
this shift.

Global/ensemble data suggest the most likely pattern evolution is
phasing much of Ivo's energy with the northern branch over norcal/or
by Thursday morning, this shifting the ridge axis further east
across the area allowing for stronger moisture advection from the
south across the entirety of the County Warning Area. Throughout the day shearing
remnants will stream inland within near westerly flow flattening
the ridge, while interacting with the deepening moisture in place by
Thursday afternoon. Timing of this shearing vorticity will be
critical for initiation of convection locally, and as of now looks
to favor northeastern Utah/Wyoming and the mountain spines south towards
the Arizona border, and lower elevations downstream at that time.
Eastward translation of this energy should allow for modest drying
again by Friday.

Thereafter the ridge is expected to rebound overhead, building north
into the northern rockies region into the weekend. Remnant moisture
will likely allow for isolated to widely scattered diurnal
convection over the terrain each afternoon, though trending
shallower in nature with time.

&&

Aviation...
light northerly winds early this evening at the kslc terminal are
expected to shift out of the northwest and increase in speed late
this evening as a cooler airmass filters in. Winds should then
decrease in speed late tonight into Monday morning, when a light
southeast drainage is expected. VFR conditions expected to persist
through the valid taf period.

&&

Fire weather...
a cold front continues to cross the state this afternoon. Gusty
winds and low humidities across northern and eastern Utah will
continue to create hazardous fire weather conditions. Expect gusty
downslope winds across portions of the western Uinta Basin and
Castle country again Monday afternoon and evening following a
night of relatively poor humidity recoveries tonight.

The next significant fire weather threat will be Wednesday into
Thursday. Increased moisture will move into southern Utah
potentially as early as Wednesday afternoon and expand north and
east Thursday. Given the very dry antecedent
conditions...lightning from this convection will present an
increased fire weather threat.

&&

Slc watches/warnings/advisories...
Utah...red flag warning until 10 PM MDT this evening for utz478>484-488-
489.

Red flag warning from noon to 9 PM MDT Monday for utz482-489.

Wyoming...&&

$$

Public...10/Kruse/Merrill
aviation...10
fire weather...Kruse

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