625 
fxus65 kslc 121907 cca 
afdslc 


Area forecast discussion 
National Weather Service Salt Lake City Utah 
1205 PM MST Friday Mar 12 2010 


Synopsis...the storm system just off the West Coast this morning 
will move southeast into Utah this weekend. This storm will push a 
cold front across the area Saturday...then focus precipitation 
over central and southern Utah Saturday night through Sunday. High 
pressure aloft will return early next week. 


&& 


Discussion...the cold core upper low off the Pacific northwest coast along 
130w still on track to move inland this evening...then southeast through 
the Great Basin Saturday/Saturday night. The various model guidance 
are all coming to a solution where the core of this system will 
track southeast across SW Utah late Saturday afternoon and evening...then 
continue southeast south of the 4-corners through the southern rockies late 
Sunday/Sunday night. This latest storm trajectory is a change from 
the more easterly path in previous models...and could result in a 
somewhat shorter duration of heavy precipitation for portions of northern/western 
Utah late Saturday night/early Sunday. Much of central/southern Utah still 
in a good position for heavy precipitation with this storm...and will 
likely see significant snowfall at the higher elevations Saturday 
afternoon through Sunday. 


The surface cold front associated with the trough still expected 
to arrive in western Utah Saturday morning. This front looks to remain 
well-defined and active across southern/central Utah where the strongest 
low-level cold advection exists ahead of the approaching trough. 
Deep convection likely to be confined to the vicinity of the front 
near the middle-level cold pool. The greatest concentration of 
thunderstorms will exist from near I-70 south to near the Arizona 
border Saturday afternoon/early evening. 


The period of heaviest precipitation likely to occur late Saturday 
through early Sunday after the upper trough closes off near the Arizona 
border. Deep layer warm advection should produce substantial lift 
along the northern/western flanks of the now developed upper low. Highest 
qpfs will likely be across the central/southern mountains...with a 
secondary maximum over the Wasatch Plateau/books cliffs and possibly 
the west/central valleys along the I-15 corridor. Numerous winter storm 
watches are currently in effect...and will likely bump up the 
southern/central mountains to a warning in the afternoon package. 


Solid ridging along the West Coast Sunday will expand into the 
Great Basin early next week. Generally warm/dry conditions will 
exist for the first half of the week...with the potential for 
precipitation and significantly cooler temperatures for mainly northern Utah late in 
the week. 


&& 


Aviation...surface winds at the slc terminal are expected to switch 
to the northwest between 20z and 23z...with a 30 percent chance that 
winds remain southerly throughout the entire day. Otherwise...expect 
VFR conditions to prevail under mostly clear skies. 




&& 


Slc watches/warnings/advisories... 
Utah...Winter Storm Watch from noon Saturday to 5 PM Sunday for utz004- 
utz008-utz009-utz010-utz014-utz015-utz016-utz517-utz518. 


Winter Storm Watch from 5 PM Saturday to 5 PM Sunday for utz012- 
utz013. 


Wyoming...none. 


&& 


$$ 


Public...Conger 
aviation...Kruse 


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http://weather.Gov/saltlakecity (all lower case) 


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visit... 
http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)