Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
404 am MDT sun Mar 16 2014
Synopsis...high pressure will strengthen across the region today.
A fast moving storm system will push a strong cold front through
the region Monday. Another storm system will graze northern Utah
Short term (through 00z thursday)...high pressure is building
over the region this morning...resulting in mostly clear skies.
Conditions will be generally quiet and quite mild with maxes
running in excess of 10f above seasonal norms for most locations.
Flow aloft is expected to switch to the west/SW tonight and tomorrow
as it increases ahead of the next approaching storm system. This
is a progressive feature that will move across northern Utah on
Monday. The trough itself is limited in moisture so precipitation will be
generally light. However...the associated front will bring a
significant cooldown to the entire state...from up to +2c at 700
mb Monday morning down to the -10c to -12c range by Monday
evening. This would result in precipitation from this system
falling as snow to northern Utah valley floors.
This front will cause a potent pressure gradient to
develop...resulting in some strong gusty winds. Have issued a high
wind watch for northwest Utah with the morning package as they
tend to get the strongest winds from a scenario like this.
However...definitely would not be surprised to see over areas that
are favored in a postfrontal regime like Castle country and
northern portions of Utah County to see at least advisory level
After Monday...GFS has moved a bit toward the ec in indicating
that shortwave energy from the trough may linger over eastern Utah
Tuesday...but the ec remains more bullish about this threat.
Still...any snow that falls will be generally light. By
Wednesday...high pressure moves back in...resulting in warming and
Long term (after 00z thursday)...a shallow cold front is
expected to slide across northern Utah Thursday morning and move into
central Utah before dissipating Thursday night. There is very little
support aloft for developing precipitation with this front except
possibly along the Idaho border. The ec produces light precipitation
Thursday morning along the border while the GFS does not. The GFS
seems to be the more likely solution but did not want to ignore the
ec completely so left a token slight chance across the extreme
Although the 700mb temperatures cool off from about -3 degrees c at slc at
12z Thursday to -8 degree c by 00z Friday they warm right back up to
about -4 degree c by late Friday. While the mountains will likely
see this upward tick on Friday...believe the northerly low level
surface gradient will keep the valleys of central and northern Utah
cooler than otherwise expected based on just the 700mb temperatures. Have
gone under MOS guidance for this reason in these areas but followed
the mosguidebc for southern portions.
Both the ec and GFS indicate a weak disturbance moving through the
intermountain region Saturday. The structure of the disturbance is
better than the Thursday system with an actual cold trough at 500 mb
associated with this system. The 500 mb-700 mb temperature spread is nearly 17-18
degrees c along with a fair amount of moisture supporting
instability in that layer. Have raised the probability of precipitation to about 80% of
climatology levels across nearly the entire region. Will likely need to
boost them but will wait to see the trend over the next several days.
Aviation...winds at the slc terminal are expected to remain
southeast through about 21-22z when the Northwest Lake breeze is
expected to set in. VFR conditions will prevail under mostly clear
Utah...high wind watch from Monday morning through Monday evening for
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