388 
fxus65 kboi 091037 
afdboi 


Area forecast discussion 
National Weather Service Boise Idaho 
335 am MST Tuesday Feb 9 2010 


Short term...today through Wednesday...extensive low clouds 
continue over the forecast area this morning and this will have an 
effect on both low and high temperatures. Meanwhile...a potent 
closed upper low is sliding south along the West Coast of 
California. This feature is spreading limited moisture and light 
precipitation over northern California...parts of southern Oregon and 
northwest Nevada. Based on the track of the low into the 
southwest...believe our zones will most likely not see any precipitation 
with this system. Did match Medford however on our western flank 
with just a slight chance of snow showers mainly this morning. Have 
excluded fog from todays forecast based on the widespread coverage 
to the low cloud deck and also the absence of any station reporting 
fog. Model soundings and cross sections indicate that low level 
moisture thins or erodes to some extent Wednesday with a deep dry 
layer above. This combined with a slight increase in flow may lead 
to a better mixed boundary layer Wednesday and more sunshine. Have 
shown this trend is the current grids. As always in low cloud 
situations without warm air advection...maximum temperature forecasts 
will be a function of sky cover. 


Long term...Wednesday night through Monday...upper longwave ridge 
will remain anchored over the western U.S through next week. 
Shortwave energy moving through the ridge will bring periods of 
light rain/snow with the focus of the precipitation shifting north early 
next week as the upper ridge amplifies. First chance of precipitation is 
still timed for Thursday morning for southeast Oregon zones and afternoon 
for SW Idaho ahead of a weak shortwave trough. Second slightly 
stronger wave moves into the region late Friday bringing greater quantitative precipitation forecast 
amounts /up to third of an inch in SW Idaho mtns/. Minor amplification 
of the ridge will shift storm track slightly northward sun/Monday with 
east-central Oregon and central Idaho zones seeing best chance of 
precipitation. 


&& 


Aviation...VFR with widespread middle-level stratus over southeast Oregon and 
SW Idaho will erode over areas south of kbno-kboi-twf line through 
the day. Areas that break out this afternoon could develop IFR 
conditions in lower fog/stratus Wednesday morning. Light winds 
surface and aloft. 


&& 


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


$$ 


Weather.Gov/Boise 


Short term...gs 
long term....dg/bb 
aviation.....Dg