Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 172118
Area Forecast Discussion
National Weather Service Salt Lake City UT
318 PM MDT Fri Mar 17 2017
.SYNOPSIS...High pressure over the region today will give way to a
very mild southwest flow on Saturday. A more active pattern is
expected to develop for the first part of next week.
.SHORT TERM (Through 00Z Tuesday)...The axis of a low amplitude
ridge consuming the eastern Great Basin has gradually shifted
overhead this afternoon per latest H5 analysis. Flow aloft is
gradually backing across the far west and will continue to over all
areas in the next 24 hours time, this in advance of the pacific
trough currently located just downstream of 140W poised to lift NE
into the PacNW.
The downstream evolution of the ridge axis and encroachment of the
trough tomorrow will allow a strengthening southwesterly flow to
develop over the area. With a very mild airmass in place, modestly
strong southerly winds (both aloft and at the surface), record
breaking temps look likely for many areas across the area. Current
forecast of 79 F for KSLC would shatter the record for the day, and
would be 1 degree shy of tying the all time record for March. Cirrus
filtering overhead from the upstream trough may at times hold temps
back a bit, but guidance does portray more of a scattered and
thinning shield as the sun angle increases tomorrow afternoon. Feel
clouds will have minimal impact on the temps, but this warrants
An ejecting short wave Sat night will sag a cold front south across
the UT/ID border region, and with decent mid level baroclinicity and
sufficient moisture, should see scattered showers develop across the
far north. Another, similar wave will return shower threats to the
border region Sunday night. Made minimal changes to grids as these
features were already well handled. The one notable change in PoPs
made was to introduce a slight chance for convective showers across
the central and southern mountains Monday afternoon as a subtle wave
lifts northeast across the area. The potential for convective
terrain driven showers exists.
The main takeaway through Monday however, will be a continuation of
well above average temps, and largely dry conditions.
.LONG TERM (After 00Z Tuesday)...Today`s model runs continue to
indicate the potential for a moderate precipitation event across
portions of southern Utah Wednesday into Thursday. A jet maxima
will transition around the base of developing trough Wednesday
afternoon. This will bring a period of upper level diffluence to
the southern portion of the state. This looks to combine with
sufficient moisture for widespread precipitation across portions
of southern Utah. The models are currently most focused on
Hanksville and south, with downslope flow limiting areas to the
north including Price. Details will be flushed out over the next
few days, but those in southeastern Utah should continue to
monitor future forecasts.
For the Tuesday into early Wednesday period, dry southwest flow
will bring a warm day to most of the state Tuesday. A weak
disturbance will cross northern Utah Tuesday afternoon into
Wednesday afternoon bringing a chance of precipitation. This looks
to be a much weaker system than the previously described for
The active period is expected to continue into next weekend.
.AVIATION...Northwesterly winds will continue at the SLC terminal
through the evening, switching to the southeast between 02-03Z.
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