979 
fxus66 kpdt 182056 
afdpdt 


Area forecast discussion 
National Weather Service Pendleton or 
155 PM PDT Friday Jul 18 2008 


Short term...tonight through Monday...upper low moving across British Columbia 
into Idaho and Montana today and tonight. Little impact on the local 
weather except for some breezy westerly winds through the evening. 
Otherwise clear skies for tonight with low temperatures similar to 
last night. A weak upper trough moves across Oregon this weekend. 
Airmass becoming a little more unstable however appears it will be 
too dry for any thunderstorms. Model cross sections are very dry 
Sat-sun and water vapor imagery shows a southerly trajectory ahead 
of the trough will not likely advect any moisture into the region. 
For now will forecast mainly clear skies with a slight warming 
trend. A stronger upper low will be located off the northern 
California coast on Monday. This pattern may support thunderstorms 
for central and southern Oregon and have left the current forecast 
with isolated thunderstorms in the afternoon and evening. 94 


Long term...Monday night through Friday...models continue to differ 
on the timing and path of a low pressure system off the coast of 
northern California. Therefore...have made few changes in the 
extended forecast due to the lower confidence from the differing 
model solutions. At this time...the low pressure system looks to 
move inland with a disturbance moving over the area on Tuesday. With 
moisture moving northward from the Desert Southwest and some 
instability...a slight chance of thunderstorms cannot be ruled out 
for Grant County north and eastward through Wallowa County in the 
afternoon and evening. At the same time...a trough of low pressure 
will be moving eastward through southern Canada and northern 
Washington Tuesday through Wednesday. This will keep temperatures a 
bit cooler on Tuesday and Wednesday. Then...the ridge off to the 
east begins to build into the area...putting the region under a 
southwesterly flow. This will lead to dry conditions and warming 
temperatures through the end of the work week. Dmh 


&& 


Aviation...00z tafs...VFR conditions under clear skies will 
continue for the next 24 hours. Breezy winds in the Columbia River 
gorge and into the Columbia Basin will continue this afternoon and 
evening before decreasing overnight. Dmh 


&& 


Preliminary point temps/pops... 
PDT 53 90 57 92 / 0 0 0 0 
alw 59 91 61 93 / 0 0 0 0 
psc 53 92 54 96 / 0 0 0 0 
ykm 52 90 52 92 / 0 0 0 0 
hri 53 92 56 94 / 0 0 0 0 
eln 54 87 54 87 / 0 0 0 0 
rdm 39 88 43 90 / 0 10 10 10 
lgd 45 90 49 92 / 0 0 0 0 
gcd 50 90 52 90 / 0 10 10 10 
dls 59 88 59 90 / 0 0 0 0 


&& 


PDT watches/warnings/advisories... 
or...none. 
Washington...none. 
&& 


$$ 


Ti:ggg 
for additional weather information, check our web site at... 
www.Weather.Gov/Pendleton 
94/84/84