699
FXUS66 KPDT 072317
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
417 PM PDT Sat Jun 7 2025

.UPDATED AVIATION DISCUSSION.

.AVIATION...00Z TAFs...VFR conditions prevail mostly due to
ridging and keeping things dry with light and variable winds. Not
expecting the pattern to change during the period. CIGs and VIS
remain well above VFR conditions with nothing to suggest otherwise
in the forecast.


&&

.PREV DISCUSSION... /issued 1241 PM PDT Sat Jun 7 2025/

SHORT TERM...Today through Monday...Main story over the period
continues to be the heat, as a strong high pressure ridge moves in
over the region by Sunday afternoon. Satellite imagery shows just
how defined this ridge is with extensive clearing just off the coast
of the PacNW. Hottest day of the period looks to still be Monday,
with much of our Basin and adjacent zones reaching triple digits by
the late afternoon. Highs will be in the mid to upper 90s elsewhere
across the lowlands.

Only real change across guidance is to keep ridging persistent until
at least the first half of Tuesday - a little longer than originally
anticipated - before SW flow starts to prevail. As far as
headlines/messaging is concerned, have opted to go with Heat
Advisories across the areas initially under an Extreme Heat Watch,
resulting in a 3-day Heat Advisory for the Basin and nearby zones.
HeatRisk does suggest that a few zones technically qualify for a
warning, but given the relatively short duration (the worst of it
only occurs on Monday) and the geographic discontinuity of the
zones, have opted to go straight Heat Advisory for the sake of
simplifying messaging. A good argument could be made either way,
however, especially given how relatively early in the season it is
for some of these areas to receive triple-digit temperatures.
Evans/74

LONG TERM...Tuesday through Saturday...With the longer persistence
of the high pressure ridge, chances for dry thunderstorms have
pushed back more into the Tuesday/Wednesday time period, but remain
concentrated over the mountains of central and eastern Oregon.
Rather than a pair of shortwaves, guidance seems to favor a more
prolonged SW flow pattern initiated by a deep low over the north
Pacific. This has also caused models to back off a bit on
instability, but the synoptic pattern does remain favorable for at
least a slight (15-20%) chance for isolated dry thunderstorms across
the aforementioned areas, even if the setup isn`t as ideal as it
appeared a couple of days ago.

Ensemble guidance strongly favors a troughing pattern prevailing
over the region Thursday onward. This will work to reverse the heat
we`re expecting this weekend, giving us more seasonable readings
(and even slightly below average) for temperatures by next weekend
with highs in the 70s and 80s. With the synoptic pattern turning
more progressive by the midweek next week, however, expect winds to
pick up through the Cascade Gaps, spilling over into portions of the
Basin. NBM already suggesting good chances (60-70%) of wind gusts
exceeding 35 mph for the Kittitas Valley and Columbia River Gorge
Wednesday and Thursday afternoon, with 20-30 mph gusts elsewhere
across the Basin and central Oregon. Evans/74

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  61  95  63  99 /   0   0   0   0
ALW  64  93  68  97 /   0   0   0   0
PSC  60  98  62 103 /   0   0   0   0
YKM  64  97  66 102 /   0   0   0   0
HRI  60  98  63 102 /   0   0   0   0
ELN  61  96  65  99 /   0   0   0   0
RDM  53  94  54  96 /   0   0   0   0
LGD  57  90  58  94 /   0   0   0   0
GCD  56  92  57  95 /   0   0   0   0
DLS  65  99  68 100 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory from 11 AM Sunday to 9 PM PDT Tuesday for ORZ041-
     044-507.

WA...Heat Advisory from 11 AM Sunday to 9 PM PDT Tuesday for WAZ024-
     026>029.

&&

$$

SHORT TERM...74
LONG TERM....74
AVIATION...95