432
FXUS66 KPDT 082312
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
412 PM PDT Tue Oct 8 2024

Updated aviation discussion

.SHORT TERM...Tonight through Thursday...Mostly benign conditions
continue through the mid to later part of the week, with a front
moving into the region helping to cool us back to near normal
temperatures with some wind and possible overnight mountain rain,
but major impacts unlikely.

A cold front is currently approaching our region and is expected
to make its way slowly across the CWA through Wednesday evening.
Rain tonight through early Wednesday should get mostly shadowed
by the Cascades, with the NBM painting a 50-70% chance at the
crests of the Cascades to see 24-hour total of a hundreth of an
inch or more by Wednesday evening; increasing this to a tenth of
an inch, probabilities decline to 20-50%. Meanwhile although the
pressure gradient should tighten with this system, winds are
unlikely to strengthen significantly. Gusts around 25-30 mph are
expected, but pressure gradients only maxing around 5-7 mb in
difference combined with a 700 mb jet only up to 35 knots will
hardly be anything to induce winds strong enough to warrant an
advisory on Wednesday. And although some of this breeziness could
promote enhanced fire conditions, moisture follows with this
system and our minimum RH`s rise notably into the 30-50% range
which will help preclude critical conditions.

After this system moves through by tomorrow evening, more benign
weather persists through early Friday morning. Temperatures will
drop around 5 to 10 degrees tomorrow, with widespread high 60`s to
mid 70`s for our population centers, and another 2-6 degrees on
Thursday, placing us closer to normal in the mid to upper 60`s
aside from perhaps The Dalles at just over 70. Some scattered
clouds in the wake of the front linger, with light winds for the
day to send us into the end of the week and weekend. Goatley/87


LONG TERM...Friday through Tuesday...

Bottom Line Up Front

1. Benign weather through Sunday with seasonal temperatures

2. Pattern change leading to the potential for low elevation and
   mountain showers.

The long term looks to be relatively benign, especially through
Sunday. Models show a weak upper level ridge set up over the region
through Sunday ahead of an upper level low that will move into the
region. Models are in relatively firm agreement with the track of
the upper level low sliding farther down the coast and clipping
northern California leaving the PacNW dry. Models then show another
upper level closed low sliding down the coast of Canada and making
its way into the PacNW Monday.

Temperatures under the ridge will be warm. However, the EFI is
signaling temperatures to be mostly at or just above seasonal
normal. 50% of the raw ensembles show the temperatures along the
foothills of the Blue Mountains and the Columbia Basin to be in the
low to mid 60s with isolated pockets seeing upper 60s. 47% of the
raw ensembles have central OR and north central OR as well as
through the eastern mountains in the low to mid 70s with a few
locations such as the John Day Basin seeing upper 70s to low 80s.
Temperatures will slowly increase each day maxing out Monday ahead
of the next incoming system with most areas seeing mid 70s.

Models are in decent agreement with the upper level low that will
make its way into the region with the leading edge along the
Cascades expected by Monday morning. Clusters show there is a bit of
a variance in the timing and positioning of the center of the low.
Some models, show the upper level low tracking a bit farther north
while others bring it closer to the PacNW. There is also the timing
variance with the models lagging nearly 6 hours. Regardless,
mountains showers are expected to begin Monday night with 30-50%
probabilities of near 0.10 inches of rain along the Cascades
beginning Monday. As the system continues to move over the region,
30-40% of the raw ensembles show the rain to spread across much of
the region with the exception of the Basin, that these areas could
see 0.01 inches and the Blues have 30-50% probabilities of also
seeing up to 0.10 inches of rainfall by Wednesday. Probabilities of
rain will continue through the remainder of the long term with
confidence in the amounts being low (20-30%) as this is all the way
out to days 7 and 8. Bennese/90


&&

.AVIATION...00Z TAFs...VFR conditions expected through the
forecast period with some FEW-SCT200. Smoke will continue to impact
RDM and BDN with smoke aloft. Winds will be 5-15kts through the
evening then become light overnight before increasing again
Wednesday afternoon.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  47  71  42  64 /   0   0   0   0
ALW  52  74  46  68 /   0   0   0   0
PSC  52  75  45  68 /   0   0   0   0
YKM  45  72  35  67 /   0   0   0   0
HRI  52  74  45  68 /   0   0   0   0
ELN  47  67  37  66 /  10   0   0   0
RDM  40  70  39  67 /   0   0   0   0
LGD  44  72  44  68 /   0   0   0   0
GCD  43  74  45  73 /   0   0   0   0
DLS  53  71  45  71 /  10  20   0   0

&&

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

$$

SHORT TERM...87
LONG TERM....90
AVIATION...90