Weather

938 
fxus66 kpdt 071538 
afdpdt 


Area forecast discussion 
National Weather Service Pendleton or 
840 am PDT sun Sep 7 2008 


Short term...dry and stable conditions and light winds will 
continue today. A highly amplitude ridge remains offshore...and 
eastern Washington/or will be under a dry northwest flow aloft. The middle level 
clouds that spread across the Columbia Basin earlier this morning 
have dissipated under strong subsidence...so skies will be sunny 
across the forecast area today. Forecast on track and no updates 
are planned for the zone package. Johnson 




Aviation...18z tafs...VFR conditions with mostly clear skies will 
continue for the next 24 hours. Surface winds are expected to remain 
10 kts or less through the day and overnight. 




&& 


Previous discussion... /issued 346 am PDT sun Sep 7 2008/ 


Short term...tonight through Monday night. Tonight the ridge is 
flattened slightly by a very weak disturbance. Late Monday and 
Monday night there will be a transition to a weak trough axis over 
the Pacific northwest. The GFS model does not show much impact from 
this upper-level pattern change...other than enough lift for some 
middle and high level cloudiness...and the European model (ecmwf) model is even less 
energetic. 80 


Long term...Tuesday through Saturday night...a disturbance ahead of 
a trough of low pressure over British Columbia and Alberta will move 
through the area on Tuesday...followed by the trough dropping south 
by Wednesday. The models agree on this general scenario...however 
the details differ. The GFS brings the trough over eastern 
Washington and Oregon...while the European and Canadian swing the 
trough south through the Idaho Panhandle and western Montana. The 
latter scenario seems to be the consistent one...and thus the one to 
follow. This will bring breezy conditions to the area Tuesday 
afternoon and into the late evening. Temperatures will cool Tuesday 
and Wednesday as colder air moves southward with the system. The 
ridge of high pressure off the Pacific northwest coast will then 
edge into the area on Thursday for warming conditions and clearing 
skies. Another system will approach the Pacific northwest coast 
Thursday night and move through the area on Friday. This system 
appears to be dry...and likely will only bring an increase in clouds 
and wind to the area. The ridge will then rebuild behind the system 
on Saturday. Dmh 






&& 


Preliminary point temps/pops... 
PDT 79 48 81 49 / 0 0 0 0 
alw 80 53 82 54 / 0 0 0 0 
psc 83 53 84 51 / 0 0 0 0 
ykm 81 57 82 50 / 0 0 0 0 
hri 81 45 83 47 / 0 0 0 0 
eln 80 47 83 51 / 0 0 0 0 
rdm 81 41 83 42 / 0 0 0 0 
lgd 76 42 81 43 / 0 0 0 0 
gcd 78 44 84 48 / 0 0 0 0 
dls 85 53 87 55 / 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 
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