Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
954 PM MDT Monday Jul 21 2014
Synopsis...a dry southwest flow will be over the area through
Tuesday. Moisture will increase from the south again on Wednesday
and could linger across mainly southern and eastern Utah through
the end of the week.
Discussion...a dry southwesterly flow prevails across much of the
forecast area this evening...as the middle level ridge axis remains
centered across the southern rockies. The exception is far
northwest Utah...where strong thunderstorms developed this
afternoon/evening along a 700mb thermal gradient where a ribbon of
instability and moderate shear was present. This activity has
largely shifted north into southern Idaho...however the associated
outflow continues to surge south across the northern Wasatch
front...and may reach northern Salt Lake and Tooele valleys before
The middle level ridge is forecast to strengthen during the day
Tuesday maintaining a dry airmass across the forecast area. By
Wednesday moisture which is currently spreading westward across Arizona
is forecast to be pulled northward across the forecast area.
Initial round of convection with this activity will likely be high
based given the dry boundary layer currently across the area...and
there are hints in the GFS suggesting extensive cloud cover may
limit the coverage of any storms which do develop.
Aviation...a wind shift to the north is expected at kslc between
0415 and 0430z...with the north wind likely persisting until
around 06z when southerly drainage flow should redevelop. There is
a 30 percent chance this switch to the northwest does not occur.
Regardless...VFR conditions are expected through the
night...although there is a 20 percent chance smoke from nearby
wildfires results in a period of MVFR visibility Tuesday morning.
Utah...red flag warning until 10 PM MDT Tuesday for utz478-492-495.
For more information from National oceanic and atmospheric administration/S National Weather Service visit...
http://weather.Gov/saltlakecity (all lower case)
For frequently asked questions about the area forecast discussion
http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)