636
FXUS66 KPDT 121911
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1211 PM PDT Sat Sep 12 2026

.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 /18Z TAFS THROUGH 18Z SUNDAY/...
VFR conditions are expected through the first 6 hours of the
forecast period. Winds will begin to increase from the northwest
later this afternoon and into this evening, with breezy
conditions prevailing through the morning on Sunday. Light rain
is expected to move into the region late tonight, with the
highest confidence of rain occurring at the northern sites.
Along with the light rain, lower cigs will filter into the area,
with MVFR conditions setting in between 09Z and 12Z and
persisting through the remainder of the forecast period.

&&

.Preliminary Point Temps/PoPs...
PDT  76  46  63  44 /   0 100  70  40
ALW  79  51  63  50 /   0 100  80  70
PSC  80  48  64  46 /   0  90  80  30
YKM  76  50  62  45 /   0 100 100  10
HRI  79  47  65  46 /   0 100  60  30
ELN  72  44  57  41 /   0 100 100  20
RDM  71  36  61  33 /  10  90  10   0
LGD  81  45  62  43 /   0  90  60  60
GCD  81  44  61  40 /   0  90  40  10
DLS  77  52  66  51 /  20 100  60  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Flash Flood Watch from 5 PM PDT this afternoon through Sunday
     evening for WAZ030.
OR...Flash Flood Watch from 5 PM PDT this afternoon through Sunday
     evening for ORZ502.

&&

$$

DISCUSSION...18
AVIATION...99