818 
fxus65 kboi 070344 
afdboi 


Area forecast discussion 
National Weather Service Boise Idaho 
945 PM MDT Monday Oct 6 2008 


Discussion...warm frontal clouds spreading rapidly eastward across 
the area in Oregon and extreme SW Idaho. Meanwhile...well defined 
cold frontal band extends from Seattle south to Portland and the I-5 
corridor. Cold front appears to be ahead of old model schedule but 
new 00z NAM is catching up with this faster timing. Will need to 
make some sky cover adjustments on the evening update to account for 
increased cloud cover tonight...otherwise front looks to be mostly 
dry in our area with an Tuesday afternoon frontal passage in SW Idaho. A mild 
day on tap Tuesday before front crosses then winds increase Post 
frontal. This scenario already covered by latest forecast. Update 
to zones forthcoming 


&& 


Aviation...a cold front will approach the forecast area late 
tonight...for isolated rain showers and brief MVFR ceilings and 
obscuration over higher terrain. Expect isolated IFR conditions in 
fog at kbno...kbke...and kmyl and adjacent mountain valleys from 
about 12z to 16z. Surface winds will be light to moderate southeast 
becoming moderate west to northwest after 18z. Winds aloft will be 
moderate to strong southwest to west. 


&& 


Previous discussion...tonight through Wednesday...next Pacific system 
will track northeast into southwestern Canada and will carry the 
bulk of dynamics and precipitation well north of the area. A cold front 
extending southwest from the parent low will move through southeast 
Oregon Tuesday morning and across southwest Idaho Tuesday afternoon. 
Initially...there will be enough moisture with the front to warrant 
a low threat of showers across the northern mountains...but once it 
reaches points to the south it becomes moisture starved. Main 
affects with the front will be gusty afternoon winds...especially at 
higher elevations where wind gusts to 40 miles per hour are possible...and 
cooler temperatures on Wednesday. Ahead of the front...temperatures 
will reach the 70s in the lower valleys Tuesday afternoon. 


Long term...Wednesday night through Monday...potent upper level 
trough will dig south along the British Columbia coast late Wednesday/early 
Thursday. Trough will continue to strengthen on Thursday...setting 
up over the intermountain west by Friday. Models have struggled 
considerably in the representation of this system and still lack 
consensus with respect to strength and location. European model (ecmwf) remains more 
aggressive than operational GFS and closes off upper wave over 
northern Nevada/southern Idaho early Friday. Despite model discrepancies - 
confidence slowly increases in unseasonably cool weather. Forecast 
temperatures 10 to 13 degrees below middle-October normals Thu/Fri/Sat. 
Have also increased areal coverage of precipitation Fri/Sat. Snow 
levels forecast to drop as low as 3600 feet Friday night/Saturday 
morning with cold core over the forecast area. Conditions will trend 
warmer and drier by Monday as closed low exits the area. 


&& 


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


$$ 


Weather.Gov/Boise 


Discussion...gs 
previous discussion...bw 
long term....Mt/dd 
aviation.....Jt