Scientific Forecaster Discussion
fxus65 kslc 200319
Area forecast discussion
National Weather Service Salt Lake City Utah
918 PM MDT Sat Aug 19 2017
Synopsis...southerly flow aloft next week will bring an increase
in mid-level moisture, leading to increasing showers and
thunderstorm chances by midweek. Eclipse viewing will likely be
hampered by clouds in southern Utah.
Discussion...an upper low remains in place off the Southern
California coast this evening while a deformation axis currently
across central Utah continues to lift north. This deformation zone
has served as the focus for showers and a few thunderstorms once
again today. Mesoscale analysis shows cape values a bit higher than
yesterday, and as a result, shower coverage increased slightly and
the stronger storms exhibited higher reflectivities. Outflow winds
of 30-40 mph or greater were also more widespread. With the loss of
daytime heating, expect most of these showers and thunderstorms to
wane with very little activity persisting past midnight.
Moisture is still expected to increase from the south late in the
day tomorrow, but even so, it will not amount to a significant
surge. Also, with the deformation zone having exited the area
tomorrow with no other notable source of lift, expect convection for
much of the afternoon tomorrow to remain confined to the higher
terrain. Later in the day and into the nighttime hours, both
mountain and valleys of southern Utah could see showers as the
moisture works its way into the area.
With much of sunday's and even monday's convective activity expected
across the south, clouds will likely be present across southern Utah
during monday's eclipse, although skies will probably not be
completely overcast. Northern Utah will stand a better chance for
eclipse viewing. That being said, a trough crossing the northern
rockies could still result in a band of thin mid/high clouds across
portions of northwest Utah and along the Idaho border.
Updated the forecast earlier to increase coverage of evening
showers/thunderstorms. No additional updates at this time.
Aviation...VFR conditions are expected at the slc terminal through
the night. Winds will become established out of the south by 04z.
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