Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
322 PM MDT Tuesday Oct 21 2014
Synopsis...a Pacific cold front will stall across central Utah
tonight with weak high pressure building in on Wednesday. Dry and
mild southwest flow will return for Thursday through Saturday.
Short term (thru 00z sat)...the upper trough continues to lift
northeastward towards the northern plains this afternoon with a cold front draped
across the north central County Warning Area. This front is stalling out and will
shift a little further south to near a Milford to price line
before stalling this evening.
Showers and isolated thunderstorms continue to form along the stalling
front this afternoon and a few light showers have reformed across
the far north ahead of one final vorticity lobe before the trough axis
The showers will linger along the front into the night then
dissipate before morning. The far northern showers should end early
this evening and clearing skies over the north should allow temperatures to
dip to chilly levels tonight.
Weak ridging aloft follows this trough for Wednesday and the old front
lifts north as a warm front. Only expect some cloudiness and no precipitation
with this warm front. The ridge axis shifts east Thursday but heights
continue to rise Thursday and Friday with a warm dry southwesterly flow in place.
Occasional high cloudiness crosses the County Warning Area Wednesday through Thursday then is
forecast to lift north with a sunny warm day on tap for Friday with
local S winds in the western valleys.
Long term (after 00z saturday)...strong trough moving onto the West
Coast Friday night will gradually lose some of its punch as it
transforms into a broader trough as it progresses across the Great
Basin Saturday and Sunday. Nonetheless...southwest winds will
increase across the western valleys Friday night and Saturday. This
will result in mild temperatures Friday night and pretty warm
temperatures for late October on Saturday.
The ec and GFS have come into timing and strength agreement for the
trough with the cold front moving through the central Wasatch front
about midnight Saturday night and into southeast Utah Sunday
evening. The best dynamics remain over northern Utah so does not
look very promising for showers across the south. Have backed off on
probability of precipitation for southern and southeast portions of the County Warning Area for Sunday. Have
added some slight chance probability of precipitation for the northern mountains into Monday
as the 500 mb cold pocket still hanging on.
Ridge builds in for late Monday and Tuesday for a warming trend by
Aviation...gusty northwest winds will continue at the slc terminal
through this early evening with gusts in the 15-20 miles per hour range but
will relax this evening. Winds are not expected to shift to the
southeast until after about 09z with a 20 percent chance of
occurring by 07z.
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)