285 
fxus65 kmso 070914 
afdmso 


Area forecast discussion 
National Weather Service Missoula Montana 
314 am MDT Tuesday Oct 7 2008 


..windy today across the intermountain region and a big change 
coming the end of the week through the weekend... 


Discussion...a surface warm front and the nose of a strong 
Pacific jet is bringing widespread steady rain to the Idaho 
Panhandle and northwest Montana this hour. This area of rain will 
encompass all of northwest Montana and the northern Clearwater 
Mountains by day break. A fast moving cold front will change the 
rain over to showers by afternoon with strong southwest to west 
winds affecting all of north central Idaho and western Montana. 
Believe speeds will remain below advisory criteria...but an 
occasional gust to 40 miles per hour is expected throughout the day. The 
higher terrain will be the exception including the mountain 
passes. Persons driving high profile vehicles should use caution 
if traveling over the passes today. With the strong west winds 
aloft...most of the north south oriented valleys will be shadowed 
from the precipitation today...and may even see some sun this 
afternoon as downslope winds will provide some clearing. 
A progressive west flow with the strong jet will remain entrenched 
over the intermountain west through Wednesday. The surface 
gradient will weaken and the lower atmosphere will stabilize 
enough that winds will not be as strong. The higher elevations 
will continue to experience strong west winds and orographic 
showers through Wednesday. 


Models are coming to an agreement with the weather system for the 
end of the workweek into the weekend. The European model (ecmwf) has been the most 
consistent showing a Pacific trough digging over the intermountain 
west Thursday night and Friday...and the GFS and NAM are coming in 
line with this solution. Have modified forecast to increase 
chances of precipitation Thursday night and Friday and lowered 
temperatures Friday through the weekend. Still some uncertainty 
where the low will develop...but all agree this will occur. Expect 
much colder conditions with snow levels down to all valley floors 
by early Friday morning and remaining cold through the weekend. 
Temperatures will be some 15 to 20 degrees below normal with snow 
from Interstate 90 and locations south. Accumulations still in 
question but looks like winter may arrive early this year. Models 
in general agreement that the aforementioned low will move 
northeast by Monday with a ridge nosing into the intermountain 
west. Temperatures will warm back to near seasonal by the beginning 
of next week. Stay tuned to later forecast for possible winter 
highlights this weekend. 




&& 


Aviation...a strong upper level jet and associated surface cold 
front sweeping through the region will bring rain to the north 
this morning transitioning to showers this afternoon. Strong 
southwest to west winds will also be common at all airfields late 
this morning through evening. The valley winds and showers will 
decrease after midnight...but mountain winds and showers will 
continue. All airfields will be impacted by winds and scattered 
showers obscuring mountains and passes. 




&& 


Mso watches/warnings/advisories... 
Montana...none. 
Idaho...none. 
&& 


$$ 


Discussion/aviation...Mead