Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
929 PM MDT Thursday Aug 21 2014
Synopsis...a weak system will lift through southeastern Utah
tonight into Friday. A cold trough will move across northern Utah
Friday night and Saturday. The cold front with this system will
move into northern Utah Friday afternoon then across the state
Friday night through Saturday.
Discussion...a cool upper trough is digging into the pacnw states
this evening. A weak upper low is over the lower Colorado River valley
with Utah under a southwesterly flow between these features.
Scattered showers and isolated thunderstorms continue across the
northern County Warning Area this evening and should persist past midnight under
increasing upper support from the approaching pacnw trough.
Scattered showers and isolated thunderstorms also persist across
south central Utah this evening as the weak low to the south begins to
open an lift northeastward. This process should spread showers over more of
the southeast tonight lasting into Friday.
The Pacific northwest trough will begin moving into the Great Basin
on Friday. The associated cold front will enter northern Utah on
Friday afternoon...and then slide through most of the County Warning Area Friday
evening and Saturday morning. This looks to be the first fall trough
and the front should have plenty of moisture in place to work with
likely generating widespread precipitation across the northern and central
County Warning Area Friday night through Sat morning.
Precipitation should taper off fairly quickly Saturday afternoon
or evening...as cool stable air moves into the area behind the
Updated forecasts earlier to raise probability of precipitation southeastern Utah overnight and
keep scattered coverage of precipitation over a larger portion of the
north. Made a few tweaks to sky cover as well. No additional
Aviation...southerly winds are expected to prevail through the
night at the kslc terminal. There is a 20 percent chance that
winds will become light and variable or light northerly at times
between 05-07z. Outflow from passing showers could also create
brief erratic gusts through the night and into the morning.
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