Scientific Forecaster Discussion
fxus65 kslc 210426
Area forecast discussion
National Weather Service Salt Lake City Utah
926 PM MST Tue Feb 20 2018
Synopsis...a winter storm that impacted much of Utah will finally
exit the area this evening. A series of weather disturbances
trailing this storm will impact the area for the middle to latter
part of the work week.
Short term (through 00z saturday)...clearing skies, very cold
temperatures aloft, generally light winds and new snow cover will
all combine for a very cold night across the entire area. An
increase in mid and high clouds late tonight will Stem the
temperature fall a bit across western and northern Utah, though
by then readings will already be near the coldest levels of this
winter season across most of the state.
The weak upper level moving southeast out of Oregon later tonight
will turn east and cross the Great Basin Wednesday through early
Thursday. This feature lacks for both thermal advection and
dynamic lift for significant lift and will be moving through what
will be a fairly stable and somewhat dry air mass. Not seeing
much in the way of precip from this feature, so the low End
Mountain pops look spot on for now.
The next trough on Friday has the potential to produce widespread
snow Thursday night/Friday, with the greatest amounts across
southern and central Utah. Higher pops look justified for the
southern two-thirds of the forecast area. Uncertainty still exists
on how far north the heavier snow extends, so will keep the pops
a bit lower due to this uncertainty.
Issued an earlier update to remove snow showers and lower temps a
bit as the early evening readings were already close to the
forecasted overnight lows.
Previous long term (after 00z saturday)...a relatively cold
trough will continue to pull away from the area at the start of
the long term forecast...with remnant snow showers continuing
across at least the southern Utah mountains. The pattern will
remain active with a series of waves riding down the eastern side
of the Pacific high. The next system is expected to impact Utah
Saturday into Sunday, though global models vary on the exact track
of this system and the resulting coverage of precipitation across
While much of the global model guidance indicates the pattern will
stay relatively active and cold next week, the details are
inconsistent at this point. Kept pops above climo for much of the
extended forecast period across at least northern Utah as confidence
in timing is quite low at this time.
Aviation...light southerly winds will continue at the slc terminal
through the overnight hours. Otherwise, a cold night is in store for
the terminal with temperatures falling to near 10f by early morning.
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