757 
fxus65 kmso 112055 cca 
afdmso 


Area forecast discussion...corrected 
National Weather Service Missoula Montana 
254 PM MDT Sat Oct 11 2008 


Discussion...a very slow and cold upper low over southeast Idaho 
will continue to impact eastern Idaho and southwest Montana over 
the next 24 to 36 hours. Southern Lemhi County through southern 
Silver Bow counties will continue to be most impacted by this 
feature with snow and strong winds creating hazardous winter 
conditions. Therefore the winter highlights will continue...please 
see west/W/a section below for details. North and west of this 
system...downslope winds are resulting in rather pleasant 
conditions with near average temperatures and only a few clouds. 
The exception is the winds which are strong across all of north 
central Idaho and western Montana. The pressure gradient 
responsible for these winds will decrease north of Missoula 
overnight allowing temperatures to plummet under mostly clear 
skies. Missoula and locations south can expect winds to stay up 
overnight along with clouds to keep temperatures more mild. The 
scenario will be very similar on Sunday...although the winds will 
not be as strong as today. The upper low will finally push off to 
the northeast Sunday night as a weak upper ridge noses into the 
region. A lingering jet on the back side of exiting low and north 
winds along The Divide have kept the mention of showers going in 
the forecast Sunday night. Monday will see temperatures warm back 
toward seasonal as winds increase from the west to southwest. 


Tuesday through Saturday...models are coming into fairly good 
agreement with a shortwave trough passing through the northern 
rockies on Tuesday. This feature will quickly pass through the area 
with precipitation chances beginning in northwest Montana early 
Tuesday morning then transitioning south and eastward through the 
day. 


The upper level flow will become a progressive west flow through 
Thursday with another shortwave trough possible late Wednesday. 
The GFS and European model (ecmwf) show strengthening divergence in their solutions 
with the European model (ecmwf) favoring a high pressure ridge while the GFS favors 
a moist southwesterly flow for the end of the week. Went close to 
climatology for the end of the week with mainly mountain showers 
possible to account for the differences. 




&& 


Aviation...slow moving upper low will continue to impact flight 
operations across eastern Idaho and southwest Montana with lowered 
ceilings and snow obscuring terrain. Ksmn and kbtm are the main 
terminals impacted by this feature. Central and northern Montana 
and Idaho are experiencing downslope/drying conditions from strong 
east winds from the aforementioned system. Gusty winds will 
continue to affect central and northern airfields this 
evening...but will decrease after midnight. 




&& 


Mso watches/warnings/advisories... 
Montana...Winter Storm Warning until 6 PM MDT Sunday above 5000 feet for 
Butte/Blackfoot region. 


Idaho...Winter Storm Warning until 3 am MDT Sunday above 4500 feet for 
eastern Lemhi County. 


&& 


$$ 


Short term...Mead 
long term....kitsmiller 
aviation...Mead