Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 012344 AAA

Area Forecast Discussion
National Weather Service Pendleton OR
443 PM PDT Sat Oct 1 2022

Updated aviation discussion

.SHORT TERM...Tonight through Monday night. Low sensible weather
concerns through Monday night. The main weather highlights revolve
around drying and warming into early next week. Highs will be
warming a few to several degrees each day with readings generally
around 10 degrees above seasonable normals by Monday. Latest
water vapor imagery shows the forecast area between a upper ridge
across the PacNW coast into British Columbia and a closed low over
the ID/WY border. Generally clear skies, except some mountain cu
in the northeast and WA Cascades.

High confidence in quiet and fair conditions the next 60 hrs.
Latest surface obs show modest northeast/east winds on the
backside of the low currently with gusts peak 20-25 mph across
north central OR into western south central WA. These winds will
slack off this evening. The aforementioned upper ridge will then
evolve and build into central OR/WA by Monday. Meantime, this
upper ridge in tandem with light flow aloft and an innocuous
surface pattern will keep breezes light tomorrow and Monday
afternoon. High confidence (90%) in gusts staying light and under
25 kts both days. Meantime, skies will be generally clear to
partly cloud under northerly flow aloft. This matches the latest
HREF forecasts well, along with our overall thinking.

.LONG TERM...Tuesday through Saturday...The extended period will
be dry and warm. The upper level ridge will persist over the
region allowing for temperatures to gradually increase through the
week and be about 10 degrees above seasonal normal. Winds will be
calm with the typical diurnal wind pattern in effect. Even with
the warm temperatures, low RH values and no season ending event,
no critical weather is expected.

GFS/ECMWF/NAM models are in strong agreement that the axis of the
ridge will be over the CWA by Tuesday albeit tilted towards the
east. Northeast flow aloft will persist over the region and
temperatures will likely hit the peak. Local winds will be light
across the region and mostly terrain driven with slightly higher
winds along the Oregon Cascades and Central Oregon. Expect gusts
up to 12kts in those areas during the evening hours and to
steadily increase to near 15 kts by the end of the period. ECMWF
EFI is still signaling above average seasonal temperatures for the
Basin, Foothills of the Cascades and into Central Oregon and
Washington through the period. NBM is hinting that the highs will
peak on Tuesday and stay relatively consistent through the week.
Highs are expected to be in the low 80s for the Basin, adjacent
valleys and Central Oregon and in the mid to high 70s along the
higher terrains.

By Friday and into Saturday models are diverging with the ECMWF
showing there to be a stronger ridge and the GFS is showing a
weaker ridge with a shortwave sliding down the eastern portion of
the ridge. The WPC EOF patterns are showing the variance and
highlighting the differences between the strength and location of
the ridge. The WPC cluster analysis is showing that there is
nearly an equal chance as to which outcome will dominate towards
the end of the extended period. Cluster 1 and 3 are showing the
GFS trough pattern with just over half of the members in
alignment, becoming the dominant pattern bringing with it slightly
more seasonal temperatures and increased winds. Cluster 2 and 4
with just under half of the members, keep the strong ridge
pattern bringing warm temperatures and light winds. Current
agreement is favoring the GFS. Regardless of the outcome, no
precipitation is expected and temperatures will not vary greatly.


.AVIATION...00Z TAFs...VFR conditions are expected to continue for
the next 24 hours. CIGS will be generally SKC though FEW cumulus
clouds around 7K feet AGL are possible near the mountains this
afternoon and again tomorrow afternoon. Have limited mention of the
mid level clouds to YKM for the next few hours. Winds will be light
and follow typical diurnal patterns tonight and tomorrow morning.
Otherwise winds will remain below 12 kts in a generally east to
northeast direction this afternoon and tomorrow afternoon. Perry/83


PDT  47  79  48  80 /   0   0   0   0
ALW  50  79  51  81 /   0   0   0   0
PSC  53  82  53  83 /   0   0   0   0
YKM  48  82  47  82 /   0   0   0   0
HRI  50  82  51  83 /   0   0   0   0
ELN  49  80  48  80 /   0   0   0   0
RDM  39  78  43  80 /   0   0   0   0
LGD  44  75  45  78 /   0   0   0   0
GCD  43  78  45  81 /   0   0   0   0
DLS  54  85  53  86 /   0   0   0   0




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