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Area forecast discussion 
National Weather Service Salt Lake City Utah
344 PM MDT Friday Aug 29 2014

Synopsis...high pressure over the region will shift east through
tonight. A storm system will bring a cold front through northern
and central Utah Saturday and Sunday. A more stable airmass will
return for the early to middle part of the upcoming week.


Discussion...high pressure over the forecast area has begun to
shift east this afternoon as a Pacific northwest storm system
moves onshore. Some shortwave energy moving through the ridge has
allowed a few showers and thunderstorms to develop over the higher
terrain of Utah...primarily over the uintas. The possibility of
convection over the terrain continues through the evening and
overnight hours as the wave moves through. Otherwise...skies have
been partly cloudy with temperatures topping out a few degrees
above seasonal norms.

The Pacific northwest storm system will track east over the Labor
Day weekend...moving across northern Utah Saturday and Sunday as
it does so. This will bring a cold front into northern and central
Utah as well as southwest Wyoming. Latest guidance is trending a
bit slower with the system...with the front not really entering
northwest Utah until Saturday evening. Because of
this...temperatures are expected to remain on the mild side during
the day Saturday. With shortwave energy from the storm system
approaching during the afternoon...the threat of convection
continues over the northern Utah mountains. Tightening gradient
ahead of the front will likely result in some breezy
winds...especially over southern Utah.

The front is prognosticated to move through northern Utah Saturday
night...stalling over central Utah Sunday morning. The main trough
also moves through northern Utah during the overnight
hours...which will be the best time for precipitation to develop.
However...due to relative lack of moisture think coverage will be
scattered at best. Morning forecast package covered the threat
well and made little in the way of changes to probability of precipitation for the
afternoon package.

The much colder airmass will be in place for the north during the
day Sunday...with 700 mb temperatures dropping from around +12c to as low
as +4c...resulting in maximum temperatures around 10f below seasonal norms.
Cooling will be less significant over central Utah...with almost
no change in temperatures between Saturday and Sunday over
southern Utah as conditions remain dry and mild.

One last wave is expected to graze northern Utah Sunday
night/Monday morning before the trough fully exits...but dry
conditions will allow for little...if any...precipitation. Models
agree that a drier and more stable northwest flow will move in by
Monday afternoon...allowing for a warming and drying trend through
at least the middle of the upcoming week. Global models indicating
the ridge flattening a bit by Thursday as a Pacific northwest
trough moves well north of the area...perhaps curbing the warming


Aviation...operational weather concerns are expected to be minimal
at the kslc terminal this afternoon and evening. Southeast surface
winds are expected to switch to the northwest by 22z with a 20
percent chance of shifting as late as 23z or 00z. VFR conditions
will be maintained.


Fire weather....two weak disturbances are bringing isolated showers
and storms this afternoon to the northeast and northwest
respectively. Spotty wetting rains are possible with these storms
through this evening but they will trend to dissipate with sunset. A
net drying trend will continue tomorrow as southerly winds ramp up
across the area ahead of an approaching cold front. Could see some
areas in the western valleys approach or exceed critical fire
weather conditions of low relative humidity and gusty winds tomorrow afternoon but
fuels remain at least somewhat wet from recent rains. The cold front
will move into central Utah Saturday night spreading isolated to
widely scattered showers to primarily the north/northwest but
potential of wetting rains remains low. Cooler and more stable
conditions will exist across the north Sunday and Monday while the
south will remain warm and dry. High pressure will return next week
further drying all areas...and southerly winds look to become gusty
once again middle to late week.


Slc watches/warnings/advisories...


fire weather...Merrill

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