824
FXUS66 KPDT 130541
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1041 PM PDT Sat Sep 12 2026

.Updated Aviation Discussion.


.KEY MESSAGES...
- Widespread rain is likely overnight into Sunday.Areas in the
flood watch should have many way to get alerts.

- Wind gusts above 30MPH are likely much of Sunday morning.

&&

.DISCUSSION...
A low pressure system currently located off the coast of Oregon
and Washington is moving south eastward, it should move ashore
during the afternoon. After moving inland the low should begin
steering towards the northeast. Rain should begin to develop as
it moves inland. Overnight the rain will become more
widespread.


Ensemble and deterministic gudience still remains in
disagreement on QPF totals. Holistically the CWA should see an
above normal amount of rain this time of year with EFI values
between .8 and .9 and SOT of 2 and 1 on the Oregon/Washington
border, putting emphasis on a potential for a high QPF rain
event. Overall the QPF has decreased over the last several runs
and reseeded more north toward our neighboring CWAs. NBM 10th
percentile has the Kittitas valley receiving 1" of rain and the
Colombia Basin and the Blue Mountains mostly receiving .20".
The southern leeward side of the Cascades will likely be rain
shadowed out of higher QPF totals. The 90th percentile QPF again
Has the Kittitas Valley in higher QPF values and the Columbia
Basin exceeding 1.20". Probabilities of >= .50" occurring
excluding those along southern leeward side of the Cascades
which will again be rain shadowed. >= 1" is where the Probs really
decline throughout most of the area, aside from the Kittitas
and Yakima Valley which remain >=80% chance.

Thunderstorms remain at <= 20% chance mostly occurring in the
higher elevations of the Blue Mountains overnight. A potential
exists for flooding over the Paradise and Hagen fires subsequent
flood watches have been issued for those areas.

Wind gusts probs through much of Columbia Gorge, Basin,
Kittitas Valley and Foothills of the Blue Mountains have a >90%
chance of 35mph or greater. Most of the CWA should see at least
20-30 with those areas mentioned seeing higher gusts.

Temperatures over the weekend remain well below seasonal
averages. Sundays high temperatures will remain in the 60-65F
with cooler temperatures in the higher elevations. After sunday
and through out the week temperatures will rebound to climate
norms.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
VFR conditions at most sites, which is expected to stay the
course through the period. The only terminal currently
experiencing MVFR is PSC due to reduced visibility of 5SM due to
moderate rainfall and breezy winds. This is expected to subside
shortly as winds begin to decrease slightly. YKM is also
expected to drop to MVFR condition overnight due to reduced
ceilings of 2kft related to the passing system and wrap around
moisture bringing another batch of light showers to all
Sunday morning and afternoon. RDM/BDN will be the only sites not
included in this second shower as the moisture will stay further
north. Breezy winds will return Sunday morning and afternoon
accompanied with the second wave of showers, with gusts of
20-25kts expected. 75

&&

.Preliminary Point Temps/PoPs...
PDT  48  62  44  69 / 100  60  50   0
ALW  52  62  49  70 / 100  70  70   0
PSC  52  63  45  73 / 100  60  40   0
YKM  51  61  44  68 / 100  90  10   0
HRI  50  64  44  72 /  90  60  40   0
ELN  47  57  41  66 / 100 100  20   0
RDM  39  61  33  70 / 100  10  10   0
LGD  46  61  42  70 /  90  60  70   0
GCD  46  61  40  70 / 100  40  20   0
DLS  51  65  50  74 / 100  50  10   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Flash Flood Watch through Sunday evening for WAZ030.
OR...Flash Flood Watch through Sunday evening for ORZ502.

&&

$$

DISCUSSION...18
AVIATION...75