Moxee, Washington Weather Forecast Discussion

176
FXUS66 KPDT 272315
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
415 PM PDT Sat Sep 27 2025
.AVIATION UPDATE.
.AVIATION...00Z TAFs...Mostly clear and dry conditions across the
area that will continue through the rest of the period. Not
expecting any sub-VFR conditions over the next 24-hours with no
VIS and CIG issues forecasted, except in areas with more dense
smoke/haze areas.
&&
.PREV DISCUSSION... /issued 153 PM PDT Sat Sep 27 2025/
.DISCUSSION...
Looking at the current synoptic pattern, a closed low continues to
spin over the Desert Southwest with a surface high centered over
the northern Rockies. Southwesterly flow aloft is developing over
the PacNW as a trough digs over the Gulf of Alaska. The evolution
of this system will result in a pattern shift to cooler and
unsettled weather by early next week.
In the meantime, warm and dry weather is expected across the CWA
through at least Sunday afternoon. Temperatures each day will warm
into the upper 70s to mid 80s, which is a good 5-10 degrees above
climatology. Winds won`t be a problem today, generally remaining
light. We do anticipate a slight uptick in wind speeds tomorrow
across central OR as the pressure gradient tightens over the
southern Cascades. Southwest winds will increase to 10-15 mph, but
afternoon RH values should remain above 15% despite the presence
of a thermal trough, resulting in elevated fire weather conditions
for portions of the southern Blue Mountains.
Based on recent model trends, timing has slowed a bit on the
arrival of the early week precipitation. Much of the area will
stay dry Sunday evening, with light precipitation possible
(20-30%) in the Cascades during the early morning hours. Rain
chances will gradually spread east during the day Monday as a
shortwave trough approaches the PacNW during the afternoon. Rain
chances (and perhaps a few rumbles of thunder) increase through
Monday night (to 40-70%), dropping to 10-20% by Tuesday morning.
Temperatures will be near climatology early next week, cooling to
below normal during the latter half of the week.
As we have seen the past few days, the GEFS continues to advertise
a deeper trough through midweek and the GEPS has transitioned in
that direction. Conversely, the EPS remains a bit faster and
weaker on the whole. These differences don`t appear to have too
much impact on anticipated QPF values but likely will affect the
timing that rain chances come to an end (with the GEFS solutions
lingering a bit longer). Wetting rain (>0.10") probabilities for
the entire event exceed 70% across most of the area with the
Lower Columbia Basin of WA seeing slightly lower amounts (40-70%).
Once you get south of the Columbia River Basin in OR,
probabilities for 0.25" still exceed 50%.
The slightly slower system also looks to delay the lowering of
snow levels during the midweek period. This limits the area
coverage of snow chances a bit more than yesterday`s forecast and
keeps any potential light accumulations confined to the higher
peaks of the Wallowa Mountains south of Joseph. We`re continuing
the monitor the potential for frost or freeze conditions late next
week, but confidence remains low at this time. /MJ
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT  50  83  54  77 /   0   0   0  20
ALW  57  84  59  77 /   0   0   0  20
PSC  48  84  53  77 /   0   0   0  10
YKM  50  82  55  75 /   0   0  10  30
HRI  49  83  55  78 /   0   0   0  20
ELN  46  80  51  71 /   0   0  10  30
RDM  43  84  49  71 /   0   0  10  50
LGD  47  85  53  76 /   0   0  10  30
GCD  48  85  53  74 /   0   0  10  30
DLS  55  83  59  73 /   0   0  10  40
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
DISCUSSION...MJ
AVIATION...95

NWS PDT Office Area Forecast Discussion