968 
fxus65 kboi 172056 
afdboi 


Area forecast discussion 
National Weather Service Boise Idaho 
245 PM MDT Wednesday Mar 17 2010 


Short term...tonight through Friday...cold front is draped just to 
the south of the Idaho/Nevada border...although it is difficult to pinpoint 
exactly because the winds near it are so weak. It runs about 
parallel to the band clouds as depicted in the satellite imagery 
which stretches across northern Nevada and southern Idaho. There are some 
88d radar returns within this band of clouds...but probably too weak 
for precipitation. A weak upper level trough near the pacnw coast will 
gradually strengthen and move into the area tonight. This trough 
will invigorate the front with showers possible in the southern 
portions of the County Warning Area late tonight through Thursday morning. The front 
and upper trough will drive south and east of the area late Thursday 
with a cooler...drier..and stable airmass to follow lasting into 
Friday. Winds will increase on Thursday...possibly reaching advisory 
speeds in parts of the upper Treasure valley for a time Thursday 
afternoon. Models have wavered on strength of the winds so am not 
confident at this time to issue a Wind Advisory. Temperatures will be back 
to near climatology levels Thursday and Friday. 


Long term...Friday night through Wednesday...models agree well 
Friday night through Sunday morning...with an upper level ridge over 
the Cascades decreasing in amplitude as it shifts eastward. Starting 
Sunday differences increase...especially offshore where the 
operational GFS and European model (ecmwf) bring a trough onshore while the GFS 
ensemble mean and Canadian have the trough 5 degrees further west. 
The ensemble means of the GFS...ECMWF...and Canadian show the best 
agreement...so we are relying on these solutions from Monday Onward. 
With the ensemble mean holding onto the ridge through Monday...any 
chance of showers that day will be confined to our northern 
periphery and higher mountains after a dry weekend. Temperatures 
will be a few degrees above normal through Monday...then cool as 
troughing develops over our area Tuesday and Wednesday...with 
temperatures averaging a few degrees below normal with precipitation 
probabilities near climatology. 


&& 


Aviation...conditions will be mainly VFR through tonight. After 06z 
scattered showers will develop along a frontal boundary south and 
east of kboi...with local MVFR conditions over the higher terrain 
south of the Snake River Valley late tonight through Thursday. 
Northwest surface winds will be light to moderate tonight... 
increasing Thursday to 25g40kts after 18z. Winds aloft will be 
moderate west to northwest. 


&& 


Boi watches/warnings/advisories... 
Idaho...none. 
Or...none. 
&& 


$$ 


Weather.Gov/Boise 


Short term...bw 
long term....jt/bb 
aviation.....Jt