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Area forecast discussion 
National Weather Service Reno Nevada 
225 PM PDT Friday Mar 19 2010 


Short term... 


Spring like weather expected this weekend as high pressure 
strengthens over the region. Temperatures will continue to run about 10 
degrees above seasonal normals with highs near 70 in most western Nevada 
valleys and upper 50s to low 60s in Sierra valleys. Clear skies and 
light winds are expected Tuesday with westerlies increasing a bit 
Sunday as a weather system drops through the Pacific northwest toward the Great 
Basin. Models are having some difficulty in determining the exact 
track of this system with the ec bringing it a bit further south 
into our forecast area compared to the GFS...which would lead to a 
better chane of some light showers. The main effect will be to cool 
down temperatures to more seasonal values. Carried slight chance of showers 
Sunday night into Monday with this system mainly north of I-80. 
There is some fairly cold air behind the front which could bring 
snow levels down to near valley floors if the core of the low were 
to move directly through the forecast area. Although...right now 
model solutions show this to occur just east toward central and 
eastern Nevada. North to northeasterly flow to become established 
after the front passes through Monday with the system shifting 
east. Milne 


Long term...Tuesday through Friday... 
no significant changes to the previous forecast through Thursday. 
For the new extended grids for next Friday...I raised probability of precipitation and 
lowered temperatures somewhat as a slight nod to the 12z European model (ecmwf). 


Tuesday looks like similar but perhaps slightly colder at the lower 
levels to the system that just passed through yesterday. This means 
rather anemic moisture and a glancing blow from the cold pool aloft 
which could bring a few showers. However...at this time the main 
story will be much colder temperatures from Monday to Tuesday with 
high pressure building into the Great Basin. 


Wednesday night...a system will skirt by to the north bringing some 
increase in cloud cover and west-southwest winds but no precipitation. Yet 
another system is expected to approach for Friday. This one gets a 
bit more problematic as the 12z European model (ecmwf) now has latched onto a much 
colder solution than the GFS and Canadian models/ensembles. 


Something in the direction of the 12z European model (ecmwf) is feasible given the 
recent pattern of energy dropping into the Great Basin and the fact 
that the European model (ecmwf) is at least consistent in bringing energy into the 
western Continental U.S. Beneath the Canadian mean ridge. However...it is way 
too early to go too near the 12z European model (ecmwf) solution with minimal 
support. Therefore...I modestly leaned that way by dropping highs 
several degrees over Thursday and adding in ghost probability of precipitation. Just note 
that the extreme solutions include highs in the upper 40s to middle 50s 
with snow/graupel showers and even an isolated thunderstorm with the 
European model (ecmwf) to the upper 50s to middle 60s with mainly dry conditions in the 
GFS. As is often the case...it will probably be somewhere in 
between. Snyder 
&& 


Aviation... 
VFR with no concerns through Saturday. Snyder 
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Rev watches/warnings/advisories... 
Nevada...none. 
California...none. 
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