931 
fxus65 kmso 282115 
afdmso 


Area forecast discussion 
National Weather Service Missoula Montana 
315 PM MDT Thursday Aug 28 2008 


Discussion...moisture streaming in from the Pacific has kept much 
of northwest Montana and northern Idaho under partly cloudy skies 
through the day. This moisture feed will continue through the 
night but start to retreat northward as a low amplitude ridge 
continues to build into the region producing clearing skies across 
central Idaho and western Montana. Temperatures will warm through 
Saturday as this ridge tries to establish itself in the area. A 
trough and associated cold front moving into the Pacific northwest 
will bring strong winds and the potential of some rain showers and 
possibly some thunderstorms on Saturday. During this time a 
tightening surface pressure gradient and strong middle level winds 
mixing down may create winds strong enough to warrant a Wind 
Advisory for Lemhi County. The combination of the strong winds and 
low relative humidities has prompted the issuance of a Fire 
Weather Watch for southwest Montana. 


Sunday and Monday. Confidence is growing regarding the development 
of a cold upper low pressure system. Models show the the upper low 
center moving across southern Idaho and southwest Montana which 
is a very favorable track for possible moderate to heavy wrap 
around precipitation into southwest and west central Montana...as 
well as the Glacier park area. Models also suggest a surge of cool 
air shifting southward into western Montana which should further 
enhance the moist uplift of the system and produce relatively cold 
temperatures. Snow may become a significant weather impact...especially 
over the higher terrain of western Montana. Finally...models typically 
move such systems eastward too quickly and often do not wrap the 
moisture far enough to the west into Idaho...so would not be 
surprised if significant precipitation lingers longer into Monday 
and impacts portions of Idaho as well. 


Tuesday through Wednesday night. Forecast confidence begins to 
wane as long range models diverge in solutions beyond Tuesday. GFS 
develops a cool northwesterly flow aloft with weak disturbances 
rotating through the flow. On the other hand...the European brings 
another strong low pressure system through the northern rockies. 
In either case...cooler than normal conditions will prevail. 
Uncertainty comes into play with how much below normal these 
temperatures will fall and precipitation chances. 




&& 


Aviation...gusty winds are expected to develop this afternoon 
across all of western Montana and north central Idaho. Winds are 
expected to dissipate after sunset however. Otherwise...a 
generally benign weather pattern will dominate over the next 24 
hours with cloud cover remaining confined mainly across northwest 
Montana. A few isolated showers will be possible across the higher 
terrain in this area tonight...causing some local terrain obscurations. 




&& 


Mso watches/warnings/advisories... 
Montana...Fire Weather Watch from Saturday afternoon through Saturday 
evening for deerlodge/west Beaverhead-east Beaverhead. 


Idaho...none. 
&& 


$$ 


Short term...loeffelbein 
long term....bauck/via 
aviation...via