Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
427 am MDT Friday Mar 14 2014
Synopsis...a fast-moving weather disturbance will cross northern
Utah and southwest Wyoming tonight through early Saturday
morning. High pressure will bring warm and dry conditions to the
region Sunday and Monday. The next storm system to impact the
state will arrive for Monday night and Tuesday.
Short term (through 12z monday)...the upper low across central
Arizona at time will continue on an east-southeast through the
morning hours. The deformation axis to north of the low will shift
south with the low...taking the last of any light showers out of
Utah early this morning.
The upper trough currently off the Washington/britcol coast will
continue east this morning. This feature will take a turn to the
southeast across the northern rockies/northern Great Basin later
today in response to the amplification of the upper ridge along
the West Coast.
The southwest extent of this trough will cross northern Utah and
southwest Wyoming late tonight/early Saturday. The baroclinic
structure of this feature not supportive of substantial precipitation for
the forecast area. The low-level cold advection running ahead of
the trough will focus on northern Utah while the best dynamic lift
and middle-level cold remains north and east of Utah across eastern
Idaho through western Wyoming. Sufficient lift and moisture will
exist for some precipitation across the northern zones...with
accumulating snows possible across the northern/central Wasatch
and western Uinta ranges. Adjacent valley locations will likely
see some precipitation...though no real impacts are anticipated.
The West Coast ridge is prognosticated to strengthen and expand eastward
across the Great Basin Saturday night/Sunday. Unseasonably warm
and dry conditions will exist Sunday ahead of what could be a
significant storm system impacting mainly the northern half of
the state early in the upcoming week.
Long term (after 12z monday)...global models are in better
agreement than 24 hours ago with the GFS coming around towards the
ec solution but their strength and timing are not quite in sync. The
GFS is about is about 4-6 hours faster than the ec which makes the
temperature forecast for Monday difficult. Have leaned toward the
speed and depth of the storm system according to the ec as it has
been the more consistent model. Therefore temperatures should be
quite mild early Monday ahead of the cold front with readings into
the 60s from slc southward in the western valleys and into the lower
70s over the east central and southeastern valleys. The cold trough
does not have the best structure and it is lacking a good moisture
tap...so have played the quantitative precipitation forecast down. However...the surface and 700 mb fields
show the cold front to be quite strong so have pushed probability of precipitation into the
likely category for the Wasatch and Uinta Mountains but kept the
surrounding valleys in the chance or slight chance categories.
Temperatures will be much cooler Tuesday with just about the entire
County Warning Area 15-20 degrees cooler than Monday due to 700 mb temperatures lowering by
about 10 degrees c. However...steady 4 to 7 degree f warming will
ensue each day under the developing ridge for the Wednesday through
Friday time frame.
Another trough is forecast for the following weekend but differences
in global model solutions results in low confidence on details. The
bottom line is that after the fast moving and cold system for Monday
a dry and warming trend will set in for the rest of the work week.
Aviation...no operational weather concerns are expected at the slc
terminal through today but there could be a few showers in the area
after midnight tonight which could cause some erratic winds with a
30 percent chance of ceilings below 7k feet above ground level after 03z. Southerly winds
this morning will shift to northwest at about 19z this afternoon and
likely to remain northwest through this evening.
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)