547 
fxus65 kslc 212309 
afdslc 


Area forecast discussion 
National Weather Service Salt Lake City Utah 
409 PM MST Sat Nov 21 2009 


Synopsis...the next Pacific storm system will cross the northern 
half of Utah Sunday night through early Monday. High pressure 
aloft will settle over Utah for Monday night through Thursday. 


&& 


Discussion...a weak vorticity maximum along the northwest Utah/NE Nevada border 
will race east through northern Utah early this evening. Light showers 
associated with this feature should end early this evening... 
followed by a weak shortwave ridge late tonight through early 
Sunday. 


The next Pacific trough will move into northern Utah by early Sunday 
evening...then race southeast into Colorado by early Monday morning. The 
latest collection of 12z GFS/ECMWF/Canadian models all seemed to 
have migrated to the old GFS solution. The consensus now bring fairly 
robust low-level cold advection through the state Sunday night with 
the middle-level trough/cold pool only clipping the northern extremes of 
the state. Somewhat surprised with this 12z solution as the European model (ecmwf) 
has moved towards the GFS instead of the other way around. Not 
entirely ready to sell out on the new solution...so will hedge 
towards the old European model (ecmwf) and keep a fairly energetic system moving 
through the northern third of the state into early Monday morning. Have 
adjusted the duration/amounts of snow...which could keep numbers 
at or slightly below advisory levels Sunday night/early Monday. 


High pressure aloft will settle across the interior west for 
Monday night through Thursday night. Dry conditions with a warming 
trend at the higher elevations the going forecast much of the 
coming week. The medium range guidance differ quite a bit 
Friday/Saturday...with the European model (ecmwf) bringing a rather significant 
system through Friday and much of the remaining guidance keeping 
some form of weak progressive feature over northern Utah and points 
north. With this much difference in the models...will hedge 
probability of precipitation/temperatures towards climatology with a slight bias to the European model (ecmwf) side. 






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Aviation...winds at the slc terminal will shift to the 
southeast drainage between 3z and 4z. Ceilings are expected to 
remain above 7000 feet through the evening. VFR conditions will 
prevail. 


&& 


Slc watches/warnings/advisories... 
Utah...none. 
Wyoming...none. 


&& 


$$ 


Public...Conger 
aviation...hosenfeld 


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