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Area forecast discussion
National Weather Service Salt Lake City Utah
352 PM MDT Wednesday Apr 16 2014
Synopsis...high pressure will spread across the region tonight
through tomorrow. The next weakening storm system will cross the
region late Friday through Saturday.
Short range (through 00z sunday)...skies are clearing west to
east this afternoon as a weak middle level wave exits the area. This
wave moved through quite a stable environment and produced little
in the way of precipitation...but a few buildups did pop and still remain
over the highest terrain of the south. Expect these to dissipate
just prior to sunset tonight but left mention of slight chance
probability of precipitation there for the time being.
500mb analysis indicates increased heights building in from the
west in wake of this wave at this time. Axis of middle level ridge currently
oriented along the West Coast will shift overhead tomorrow
allowing 700 mb temperatures to warm some 4 to 6 degrees c over the next 24
hours...resulting in roughly 5 to 10 f degrees of surface warming
vs those temperatures realized this afternoon.
Trough noted near 145w in water vapor will split hard as it
interacts and displaces the ridge east Friday. Should see further
and quite rapid warming beginning Friday morning as a weak cold
front associated with the northern split begins to track into the
northwest. Breezy southerly winds appear likely across the western
valleys and mountains as gradient tightens in front of this
boundary. Anticipate focus of precipitation will be coincident with the
700 mb baroclinic zone of this feature as it sags southeast then
stalls and washes out late Friday into Saturday morning. Global
models indicate the southern branch will close off over socal then
lift northeast through the 4 corners area as an open wave Friday
night through Saturday. Should see a middle level deformation develop
between these features providing focused precipitation chances across
northern then central then eastern Utah through that time. Will
likely need to adjust placement and timing of this zone as fine
details become more uniform.
Long term (after 00z sunday)...heights will slowly rise Sunday into
Monday as the weekend system moves east. Southwesterly flow will
develop Monday ahead of a large upper low that both the GFS and ec
suggest will impact much of the western US midweek next week. While
both models agree that this upper low will impact the area...there
are differences in the details between the models. The GFS closes
the low off as it moves onshore...while the ec maintains more of an
open wave. The ec is slightly faster with the associated cold
front...moving it into the state Tuesday afternoon...while the GFS
shows the cold front moving into the state Tuesday night/Wednesday
morning. Also...the ec is quite a bit colder...with 700mb temperatures as
low as -11c across northern Utah on Wednesday. In both models...the
cold front is very strong...which would result in a very windy day
on Tuesday for the forecast area.
As far as the grids...increased probability of precipitation for the midweek time period.
Though there are differences as far as timing and strength of the
system next week...both models suggest that cool...unsettled weather
can be expected midweek next week.
Aviation...winds at the slc terminal will remain from the northwest
through 03z to 05z...and then switch to the southeast drainage. VFR
conditions will prevail.
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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)