576
FXUS66 KPDT 032358
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
358 PM PST Tue Nov 3 2026

.KEY MESSAGES...
- Light showers prevail through the afternoon in the Basin into
  the Yakima/Kittitas Valley.

- Mostly dry conditions continue Wednesday and later through the
  day.

- Active weather with breezy winds through the late part of the
  week and into next week.

&&

.DISCUSSION...
Radar currently advertises light precip across the Columbia
Basin into the Yakima/Kittitas Valley that will continue through
the afternoon hours. Soundings from OTX taken at 12z show lower
level dry air, which will allow little precip to accumulate out
of this system. PoPs are tapered up to 15% through the general
populated areas north of the Blue Mountains.

Area of low pressure is located right off the coast of
California and is expected to move inland (>90% confidence) over
southern Oregon and northern California over the next few hours.
Rain chances continue to be low (<20% chance) through late
Wednesday, but conditions remain mostly dry with ridging
developing just north in British Columbia. Ridging will keep the
weather dry and slightly warmer going through late Wednesday,
but guidance is in great agreement that a shortwave from the
Pacific will move inland by late Wednesday/early Thursday. Light
precip and locally breezy winds develop with the passage,
otherwise not expecting mush of any impacts from this system
(50-70% chance).

Looking towards the weekend, EURO and GFS members are hinting of
another weather system with a shortwave embedded pushing along
the area with periods of high PoPs (50-70% chances) along the
Cascades with lower chances (10-30% chances) across east of the
Cascades and into the populated centers across the rest of the
CWA. That shortwave will then push north and northeastward into
Canada by early next week (50-70% confidence), with another
system right behind located in the Pacific. Guidance gets shaky
after Sunday/Monday with guidance struggling with the
strength and timing of the second shortwave. GFS members favors
a stronger/wetter system, while Euro members trend towards a
weaker/drier system. At this point not seeing meaningful
impacts currently, as IVT values are currently <250 kg/ms
through Monday. Still plenty of time to monitor for this
evolving forecast incase the set-up changes.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...

A broken band of rain was spreading north across the Yakima
valley with VFR ceilings should clear the area 0300 Z. Light
winds are are anticipated for all terminals overnight with some
impacts from BR/FG and stratus. HRRR and LAMP guidance brings in
1/4SM FG visibility at RDM and BDN after about 6z, which has
potential to be an impact on and off all night into late morning
Wednesday (40 to 60 percent confidence), especially given model
fields begin to clear the higher level cloud cover out by middle
of the overnight with winds remaining light. Patchy dense fog or
freezing fog along the Blue Mountain Foothills could impact the
ALW/PDT terminals overnight as (10 to 15 confidence).

&&

.Preliminary Point Temps/PoPs...
PDT  31  53  37  56 /   0   0  40  30
ALW  35  52  41  54 /   0   0  40  50
PSC  31  54  36  59 /   0   0  30  10
YKM  32  55  37  58 /   0   0  50   0
HRI  29  54  36  59 /   0   0  50  20
ELN  27  52  31  53 /  10   0  60   0
RDM  22  57  30  53 /   0   0  40   0
LGD  31  57  36  54 /   0   0  20  50
GCD  31  58  36  54 /   0   0  20  10
DLS  35  57  42  60 /   0   0  80   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...None.

&&

$$

DISCUSSION...95
AVIATION...71