028
FXUS66 KPDT 300353
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
853 PM PDT Wed May 29 2024

.SHORT TERM UPDATE...Scattered showers and isolated thunderstorms
developed over southeast WA, including the northern Blue
Mountains, but are quickly moving into Idaho. Precipitation will
end over the next couple of hours. There was also a line of
showers that developed over the central WA Cascades associated
with the Puget Sound convergence zone, but these showers are also
slowly dissipating as the northwest flow aloft weakens and the
upper level jet lifts northward. Winds are slow to decrease again
this evening, but gradients will relax with high confidence (70%)
that winds will decrease to 15 mph or less after midnight.
Forecast was updated to extend the breezy winds a few hours
longer. Another update was to add patchy or areas of smoke over
southern Deschutes and Crook Counties associated with some of the
prescribed burns earlier today. Wister/85


&&

.AVIATION...06Z TAFS...Smoke has been observed at RDM and BDN and
can also be seen on visible satellite and web cams. As the mixing
heights lower closer to the surface and winds decrease tonight,
the terminal airports will be more susceptible to MVFR or less
visibility. Otherwise, skies are mostly clear with FEW-SCT mid and
high level clouds. Breezy westerly winds gusting to 25-35 kt will
decrease tonight and will be light and terrain driven by early
Thursday morning. Wister/85


&&

.PREV DISCUSSION... /issued 435 PM PDT Wed May 29 2024/

SHORT TERM...Tonight through Friday night...Isolated to
scattered showers and isolated thunderstorms will diminish through
this evening as an upper-level trough exits to the east and an
offshore upper-level ridge influences the region`s weather.

Dry conditions are expected (95-100% chance) overnight through
Friday evening. Locally breezy winds are expected to remain
through the Cascade gaps overnight through Thursday with lighter
winds elsewhere. A brief switch to light offshore winds is
forecast Friday as the upper-level ridge axis moves overhead.

Ensemble guidance is then in good agreement (>95% chance) that a
weak shortwave trough will approach the PacNW by Friday night
with a reversal to onshore winds accompanied by low (15-25%)
chances of light precipitation along the Washington Cascade crest.
Plunkett/86

LONG TERM...Saturday through Wednesday...Saturday will see a weak
upper level trough passing over the region. Main impact will be
some increasing westerly winds of 15 to 25 mph with higher gusts.
Precipitation will be limited mainly to the Cascade crest and over
the far eastern mountains. This includes a slight chance of
thunderstorms over Wallowa County.

A deepening upper level trough in the Gulf of Alaska on Sunday
will bring the next weather system further south late Sunday and
Monday. This will start off with a weak warm front clipping the
forecast area Sunday night with some low chance POPs followed by a
cold frontal passage on Monday. This system will once again
increase westerly winds on Monday but could also see some
meaningful precipitation of a quarter to half an inch across the
lower elevations and half an inch to around an inch in the
mountains before the winds kick in.

Deterministic models dry things out rapidly on Tuesday but the NBM
keeps some lingering showers before turning dry on Wednesday.
Expect this to get resolved after a few more model runs.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  39  67  42  75 /  10   0   0   0
ALW  44  70  45  77 /  20   0   0   0
PSC  45  74  48  80 /  20   0   0   0
YKM  37  72  41  78 /   0   0   0   0
HRI  43  73  44  80 /  10   0   0   0
ELN  40  67  42  77 /   0   0   0   0
RDM  34  69  38  78 /   0   0   0   0
LGD  37  64  39  74 /  10   0   0   0
GCD  36  67  39  78 /   0   0   0   0
DLS  44  73  47  81 /   0   0   0   0

&&

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

$$

SHORT TERM...86/85
LONG TERM....91
AVIATION...85