Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
932 am MDT Sat Aug 29 2015
Synopsis...a Pacific northwest storm system will bring a cold
front into northern and central Utah tonight through Sunday. A
drier west to southwest flow will develop for the early part of
the upcoming week.
Discussion...the broad trough moving onshore along the Pacific
northwest coast this morning has shifted the ridge of high
pressure over the forecast area to the east. This is allowing for
the development of southerly flow. High clouds are making their
way into western Utah ahead of the approaching trough and will
continue to spread eastward.
A cold front will move into northern Utah tonight as the trough
moves into Washington. Moisture and instability ahead of the
system will allow for a bit of convection this afternoon over the
higher terrain as well as over northwest Utah with good jet
support on the leading edge of the storm system. Precipitation is prognosticated
to become more focused over northern Utah this evening and into
the overnight hours as the front moves through.
The passing front will have a noticeable effect on
temperatures...particularly over northern Utah. Maxes today will
be near record values for many locations...over 10f above seasonal
norms while southern Utah remains near or just slightly above
climatology. The breezy southerly winds developing ahead of the trough
today will allow for additional warming. Behind the front...maxes
tomorrow over northern Utah will be around seasonal norms...with
southern Utah high temperatures running a couple of degrees below
The trough will continue east on Sunday...moving through Idaho and
Montana through early Monday. This will shift the best moisture
and dynamics into eastern Utah...so the best coverage of afternoon
convection will move into that part of the County Warning Area. A drier and more
subsident airmass is expected to move over Utah and southwest
Wyoming behind the exiting the storm system Sunday night into
early next week.
No updates expected to the forecast this morning.
Aviation...the slc terminal will see VFR conditions throughout
the day with increasing clouds. Winds should remain southerly
throughout the day...becoming gusty at times this afternoon. There
is a 10 percent chance of a late wind shift to the northwest
between 22z and 00z. There is a 30 percent chance that showers in
the vicinity of the terminal will result in periods of erratic
winds after 00z.
Fire weather...southwesterly winds will increase across Utah today
ahead of an approaching cold front...with the strongest winds in
northwestern Utah. Shower and thunderstorm development is possible
again this afternoon...particularly in the western half of
Utah...with the best coverage of showers across northern Utah as
the wave passes through the area this evening. This storm system
will continue to push through the state on Sunday...with the most
showers expected across the eastern half of Utah. After this wave
passes...a drier air mass will move into the area for the beginning of the
work week...with increasing southwesterly winds Tuesday Onward.
Isolated critical fire weather conditions are possible today...but
the strongest winds and driest conditions do not look to line up
with the areas where fuels are critically dry. More critical
conditions may be possible during the middle and end of next week.
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)