Weather Service Report


688 
FXUS66 KPDT 220927
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
227 AM PDT Mon Oct 22 2018

.SHORT TERM...Today through Wednesday night...A upper level ridge of 
high pressure remains over the region but the first in a series of 
weather systems is beginning to weaken the ridge. This first system 
is a closed upper level low over the western Great Basin which is 
slowly lifting northeastward. There are two main shortwaves waves 
evolving around the low. The first is impacting southern Idaho with 
some showers and the other is over southern Utah. The Idaho 
shortwave will move north and bring some clouds across the eastern 
portion of the forecast area late today through Tuesday bringing a 
chance of showers. The second weather feature that will impact the 
forecast area is the upper level trough over the Gulf of Alaska. As 
the ridge weakens this trough will move closer to the Pacific 
Northwest and eventually send a series of weather systems into the 
region. The first will be a cool front that will move across the 
region Tuesday night. This front will be weakening as it interacts 
with the departing ridge so its main impact will be increasing 
clouds, some cooler air and precipitation mainly along the Cascade 
crest. Subsequent systems coming out of this trough will impact the 
forecast area during the long term portion of this discussion. 

.LONG TERM...Wednesday night through Monday...00Z operational models 
are in reasonable alignment with each other, but still seeing 
substantial run to run adjustments and poor consistency against the 
ensemble means leading to below average forecast confidence, 
especially toward the start of next week. Regardless of individual 
model variation the extended period will feature a plume of Pacific 
moisture interacting with a pair disturbances Thursday/Friday and 
Sunday/Monday bringing in increased precipitation chances with a 
flat shortwave ridge between the two keeping it dry on Saturday. 
Snow levels stay well above pass elevations during the period so 
little impact to travel is expected with either system.  Peck


&&

.AVIATION...12Z TAFs...Patchy fog near PSC/DLS/PDT again this 
morning with best chances for some brief IFR conditions at PSC 11-
15Z. Otherwise mostly clear but hazy skies through this afternoon. 
Will see increasing mid-level cloudiness over PSC/ALW/PDT by early 
Tuesday with wraparound moisture from a feature moving north through 
the Snake River Basin. Winds less than 8KTs through the period. Peck


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  64  42  66  45 /   0   0  10  10 
ALW  62  41  64  45 /   0   0  10  10 
PSC  64  38  66  45 /   0   0   0   0 
YKM  68  38  66  40 /   0   0   0  10 
HRI  65  40  66  45 /   0   0   0   0 
ELN  68  36  66  41 /   0   0   0  10 
RDM  71  33  70  35 /   0   0   0  10 
LGD  71  43  71  41 /   0  10  10  10 
GCD  73  45  72  42 /   0  10  10   0 
DLS  69  40  66  46 /   0   0   0  10 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Air Stagnation Advisory until 10 AM PDT Tuesday for ORZ041-044-
     049-050-502-503-505>511.

WA...Air Stagnation Advisory until 10 AM PDT Tuesday for WAZ024-
     026>030-520-521.

&&

$$

91/74/74

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Western Regional Climate Center, wrcc@dri.edu