Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
957 am MDT Tuesday Apr 21 2015
Synopsis...high pressure aloft will expand east across the Great
Basin today. A low pressure system along the Southern California
coast will also move inland today...then turn north and impact
much of the area midweek.
Discussion...the axis of the high amplitude upper ridge will move
into Utah today. Subsidence under the ridge should inhibit
convection this afternoon...limiting any convective precipitation to the
higher terrain with limited areal coverage. Looking at the warming
trend to continue under the ridge as near 700mb temperatures should be
around 1 to 3 degrees warmer than yesterday.
The exception to the above would be across southwest Utah this
afternoon/early evening. The upper low currently along the
Southern California coast will take a turn to the north this
afternoon...reaching far southern Nevada late tonight.
Precipitable water values will show a modest increase across
far southwest Utah in advance of the low later this afternoon.
Anticipating an increase in convective cloud cover across the
southwest during the afternoon with some showers and/or
thunderstorms possible over/near the southern/central mountains.
Convective precipitation will likely continue in some form near and south
of the deformation axis along the northeast flank of the upper low
over central Utah tonight. This axis will lift north into northern
Utah Wednesday...then dissipate as the parent low reforms back
over western Arizona Thursday. Diurnal convection over the higher
terrain should form Thursday afternoon/early evening in the
residual moisture over the state.
No updates planned for the short term forecast.
Aviation...light southeast winds at slc terminal should shift
to northwest at 18z but there is a 30 percent chance that this shift
will occur closer to 19-20z. No other meteorological operational
concerns through today.
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)