666
FXUS66 KPDT 161726
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1026 AM PDT Mon Jun 16 2025

Updated Aviation Discussion

.AVIATION...12Z TAFs...VFR conditions to prevail through the
period. A passing system will bring sct-bkn CIGS AOA 15kft to
25kft today, with clear skies developing overnight. Winds will be
increase to 15-20kts with gusts to around 30kts at site DLS this
afternoon, with winds decreasing to around 12kts overnight. Winds
will increase to 12-17kts with gusts to around 25kts at sites
PDT/RDM/BDN after 21Z, then becoming light between 5Z-8Z. Winds at
all other sites will be light, 12kts or less, through the period.
Lawhorn/82


&&

.PREV DISCUSSION... /issued 829 AM PDT Mon Jun 16 2025/

.MORNING UPDATE...A weak shortwave trough will slide across the
PacNW today and will result in chances (10-30%) of showers
developing across portions of the eastern mountains with a slight
chance (10-20%) of isolated thunderstorms developing in the
afternoon and early evening as well. Breezy to windy conditions
will also develop through the Cascade gaps today, with high
confidence (75-85%) of gusts 30-40mph developing in the eastern
Gorge and Kittitas valley. These winds will also overlap with very
low relative humidities in the Kittitas valley, resulting in a Red
Flag Warning in effect between 2PM and 9PM today. Made updates to
RHs and winds, with no other changes to the overnight forecast
package. Lawhorn/82

PREV DISCUSSION... /issued 1012 PM PDT Sun Jun 15 2025/



PREV DISCUSSION... /issued 129 PM PDT Sun Jun 15 2025/

.SHORT TERM...Today through Tuesday...Clear skies prevail across
the forecast area this afternoon as weak SW flow prevails aloft.
Monday will kick off a more active pattern through the weak as an
upper- level trough lifts through the PacNW, leaving us with
gusty conditions, showers and isolated thunderstorms across the
eastern mountains, and potentially critical fire weather
conditions for portions of our Cascade Gaps zones. Once this
trough passes through heading into Tuesday, drier weather will
return, but the winds will be pretty relentless through the rest
of the work week as we remain in an amplified wind pattern aloft.

Not much to speak of today, as most of the sensible weather
concerns in the short term fall on Monday. An upper-level
trough, which is relatively starved of moisture, will provide some
light shower activity across our far eastern mountains, namely
for the Strawberries up through the Wallowas, with a possible
isolated storm embedded around the area. There is some supportive
instability across the high mountains, but CAMs are pretty gun shy
in depicting anything of too much substance tomorrow afternoon.
That being said, will leave at least slight chance to chance PoPs
for the area, with the expectation that at least a few lightning
strikes could formulate from this system.

Bigger concern will be the winds from this system as pressure
gradients tighten. Models key in on a 7-8 mb cross-Cascade
pressure gradient, which would be supportive of wind gusts
reaching up to 40 mph across the Cascade Gaps, and 20-30 mph into
the Basin. Think there will be enough of a moisture push into the
Gorge from this southwesterly system, but the Kittitas Valley
could be more borderline for critical fire weather conditions with
drier air in place. Will leave later shifts to make an ultimate
decision, but will nonetheless highlight the potential for red
flag conditions for Kittitas tomorrow afternoon. Winds will back
off a bit on Tuesday, but will otherwise remain elevated through
the Cascade Gaps thanks to this persistent weather pattern,
leaving us with amplified winds aloft. Evans/74

.LONG TERM...Wednesday through Sunday...Little will change in the
synoptic pattern until the low pressure system, based in the Gulf
of Alaska, that is ultimately driving this amplified flow pattern
starts to push onshore by around Friday. Of this, ensembles are
in pretty good agreement, which will not only provide for more
widespread chances for showers across the forecast area, but also
a boost in RH recoveries which should (hopefully) aid in any
firefighting efforts across the forecast area.

Until then, gusty conditions will remain in place through the
Kittitas Valley and Columbia River Gorge, picking up again
Wednesday afternoon with gusts up to 40 mph and gusts in the
20-30 mph range for the Basin as a jet max circulates overhead on
the leading edge of the aforementioned low. Once the low moves
onshore, we`ll see yet another round of elevated winds, but this
will at least coincide with a rise in RHs as this system brings in
a cooler air mass. Evans/74

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  87  54  86  54 /   0   0   0   0
ALW  86  57  84  58 /   0   0   0   0
PSC  90  55  88  55 /   0   0   0   0
YKM  88  53  87  53 /   0   0   0   0
HRI  90  56  88  56 /   0   0   0   0
ELN  84  54  83  53 /   0   0   0   0
RDM  81  41  82  42 /   0   0   0   0
LGD  81  49  82  50 /  20   0   0   0
GCD  83  47  84  48 /  20  10   0   0
DLS  82  55  83  57 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Red Flag Warning from 2 PM this afternoon to 9 PM PDT this
     evening for WAZ690.

&&

$$

SHORT TERM...74
LONG TERM....74
AVIATION...82