451
FXUS66 KPDT 150001
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
501 PM PDT Tue May 14 2024

Updated Aviation Discussion

.AVIATION...00Z TAFs...VFR conditions expected over the next 24
hours. Winds breezy at RDM/BDN this evening but should lessen by
tonight. YKM will see stronger gusts start up later this evening
and should lessen again by tomorrow morning. Finally DLS may see
some breezes this evening into the night, but stronger gusts not
expected until later tomorrow morning. Skies either clear or some
high clouds possible, but CIGs will not be impactful. Goatley/87


&&

.PREV DISCUSSION... /issued 223 PM PDT Tue May 14 2024/

SHORT TERM...Tonight through Thursday Night...

Key Points for the next few days:

1) Continued breezy to windy conditions for the Kittitas Valley
becoming widespread across the area Thursday afternoon.

2) Water levels remain high along the Naches River.

Weather through the next couple of days will be quiet with few
concerns as a ridge centered offshore remains in control of our
weather. Expecting mostly clear skies with no chance of
precipitation through Wednesday night with temperatures warming 4 to
5 degrees from today with highs in the upper 70s to mid 80s. NBM
temperatures probabilities show very little spread between the 10th
and 90th profiles, so confidence is high. Winds will be the main
forecasting challenge as while pressure gradients have mostly
relaxed, they remain strong over the Washington Cascades and expect
the Kittitas Valley to see 20 to 30 mph northwest winds late this
afternoon and again tomorrow. Winds will be lighter elsewhere. By
Thursday afternoon, a trough will be sliding south through British
Columbia and flattening the ridge in to a zonal westerly flow. The
trough will bring a chance of light rain showers to the Washington
Cascade crest Thursday afternoon and night with just minor amounts
of precipitation expected. The rest of the area will be dry though
there will be increased clouds. The trough will tighten pressure
gradients and much of the area will have west to northwest winds of
15 to 30 mph, Thursday afternoon and night though it does not appear
that any Wind Advisories will be needed.

Water levels on the Naches River continue to be high with the Naches
River at Cliffdell just an inch or so below action stage. It is
expected to rise very slowly to above action stage by tomorrow
afternoon. It is then forecast to stay just slightly above action
stage through Sunday morning before dropping down below action
stage. The Naches River at Naches continues to be about six inches
below action stage but is expected to remain steady and not reach
action stage in the next week. Probabilistic forecasts give the
Naches at Cliffdell a greater than 95 percent chance of reaching
action stage while the Naches River at Naches has only a 6 percent
chance of reaching action stage, though my suspicion is that it
should be higher than that. In any event, the water levels on the
Naches River should not cause any significant impacts. Perry/83

LONG TERM...Friday through Monday...Models continue to struggle on
the strength and impact on our area of a broad upper level trough
over western Canada. EOFs depict the greatest variance in the
strength of a shortwave ridge Friday, but then it becomes how deeply
the aforementioned trough digs southward through the rest of the
period. WPC cluster analysis shows a general upper level trough over
the area with the deepest trough bouncing between cluster members
which may just be a timing issue as disturbances rotate around main
low over the Northwest Territories and Nunavut of Canada. Ensemble
members show a general trough over the area deepening through the
period with the GFS ensemble a little more broad and weaker by
Friday.  The deterministic models are quite different in their
solutions. ECMWF generally depicts weaker shortwaves moving through
the general northwest flow while the GFS is deeper. As a result, the
GFS is a little more optimistic with precipitation chances over the
mountains. At this time, the best chance of receiving 0.1 inch is
Monday with the mountains showing a moderate (45-60%) chance while
the basin, foothills and Central Oregon show a low chance (15-25%).
Overall, the weather will remain generally unsettled with
precipitation amounts remaining on the light side.

There`s a moderate-high chance (65-85%) we`ll see some breezy
conditions through the Columbia River Gorge, Kittitas Valley, and
portions of the Lower Columbia Basin Friday.

Daytime highs will be near to slightly below normal through the
period. Earle/81

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  48  79  52  81 /   0   0   0   0
ALW  53  81  56  83 /   0   0   0   0
PSC  54  86  57  88 /   0   0   0   0
YKM  49  85  51  82 /   0   0   0   0
HRI  51  85  56  85 /   0   0   0   0
ELN  51  79  52  74 /   0   0   0   0
RDM  43  80  46  81 /   0   0   0   0
LGD  45  76  49  79 /   0   0   0   0
GCD  44  78  48  80 /   0   0   0   0
DLS  53  84  56  78 /   0   0   0   0

&&

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

$$

SHORT TERM...83
LONG TERM....81
AVIATION...87