Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
1023 am MDT Thursday Aug 21 2014
Synopsis...the airmass over the forecast area will slowly dry
through Friday...although conditions will remain unsettled. A
cold trough will move across northern Utah Friday night and
Saturday. A brief warming and drying trend is expected Sunday and
Monday before another trough impacts the area for the middle of
the upcoming week.
Discussion...a weak shortwave trough is moving through northern
Utah and southwest Wyoming this morning and shows up well on
satellite and radar imagery...as it has kicked off a band of
showers and isolated thunderstorms in the northern third of the
County Warning Area. This wave will keep the north active through the day...though
some of the best activity may be confined to the far northwest
corner of Utah in the afternoon.
In central and southern Utah...the airmass is slowly drying from
the west...with precipitable water values generally around 0.6
inches. That said...enough lingering moisture should allow for
typical diurnal convection initiating along the higher terrain. In
addition...some thunderstorms could drift into far southern Utah
from Arizona through the afternoon...as a series of weak
shortwaves move up from the south.
After some drying and warming tomorrow...the focus for this
afternoons forecast package will be on the fall-like trough that
moves through the region on Friday night and Saturday...as well
as the active pattern that looks to continue into next week. With
models locking in on this cool and wet pattern...will look to see
where temperatures can be lowered even more...and where increased
confidence can allow for higher probability of precipitation.
Updated the forecast this morning to increase probability of precipitation and sky cover
through the morning hours...especially across the northern half of
the County Warning Area. No further updates are anticipated this morning.
Aviation...southerly winds are expected at the slc terminal
through the taf period...with only a 20 percent chance of a switch
to northwest winds this afternoon. Showers will continue across
northern Utah through the day...and the strongest showers could
lower ceilings below 7000ft.
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For frequently asked questions about the area forecast discussion
http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)