Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
958 am MDT Thursday Sep 18 2014
Synopsis...an upper trough will slowly advance into the western
Great Basin today through tonight then form a closed low off the
Southern California coast by late Friday. Moisture will increase
across Utah today ahead of this trough and remain into Friday.
Discussion...a Pacific trough is moving through the West Coast
this morning...with a portion of this trough expected to slide
into the Great Basin later today. Out ahead of this trough...Utah
and southwest Wyoming has sunny skies this morning...with an
increasing southwesterly flow aloft.
Additional moisture has moved over the County Warning Area overnight...with
satellite imagery indicating precipitable water values from 0.7 to
1.1 inches over the area. This moisture should help fuel showers
and thunderstorms this afternoon. In the southern half of the
state...convective activity should initiate primarily on the
higher terrain. In the north...more organized convection could
develop as the trough begins impacting the area...especially in
the northwest corner of Utah. With 0-6 km bulk shear of generally
30-40 knots...some of these storms could become severe. Will also
have to keep an eye out for the potential of localized flash
flooding...as the moister airmass could support heavy rainers. As
far as the Wasatch front is concerned...isolated to widely
scattered showers are possible through the afternoon hours...but
many people may have to wait until the evening and overnight hours
for a better chance of rainfall.
The forecast for today looks fine and no updates are planned for
Aviation...winds at the slc terminal are expected to switch to
the northwest between 21z and 23z...but there is a slight chance
that winds simply remain southerly through the rest of the day.
There is also a 30 percent chance that a thunderstorm could impact
the terminal between 20z and 02z...with gusty erratic winds as the
most likely impact. Rain will likely increase over the area after
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