981
FXUS66 KPDT 040537
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1037 PM PDT Thu Jul 3 2025

Updated Aviation Discussion

.AVIATION...06Z TAFs...VFR with occasional MVFR conditions to
prevail through the period. Remnant showers from earlier
thunderstorms are currently impacting sites RDM/BDN, but are
expected to clear out by 7Z. Tonight, shower/thunderstorm activity
will redevelop across central and southeastern OR, then will
propagate north throughout the morning and afternoon, but will be
isolated to scattered. This has resulted in PROB30 groups for
TSRA/SHRA being included at sites RDM/BDN between 10Z-16Z and
between 17Z-22Z at sites PDT/ALW. Confidence is low (10-20%) in
shower/thunderstorm activity impacting the remaining sites.
However, cannot rule out gusty outflow winds impacting site PSC in
the late afternoon. Otherwise, winds will mostly be 12kts or
less...except at site DLS where winds 12-20kts with gusts to
around 25kts will prevail through the period. Lawhorn/82


PREV DISCUSSION... /issued 206 PM PDT Thu Jul 3 2025/

.SHORT TERM...This evening through Saturday. Two distinct
circulations are evident on satellite imagery this afternoon; the
first is located off the southwest Oregon and northwest California
coast, and the second is upstream in the northeast Pacific. These
two lows are expected (>95% chance) to move onshore tonight
through Friday night and facilitate widespread chances of
precipitation. While the best chances (50-75%) of showers will
remain over central Oregon and the Blue Mountains, low (15-40%)
chances will encompass the rest of the forecast area. A chance
(25+%) of thunderstorms is forecast over central Oregon and the
Blue Mountains tonight through Friday evening, with the most
robust convection anticipated Friday afternoon along the southern
part of our forecast area in Deschutes, Crook, and Grant counties.
Thunderstorms will be capable of producing small hail, locally
heavy downpours, and strong outflow winds in excess of 50 mph.

Drier conditions are forecast by Saturday as the low exits to the
east and a drier zonal flow moves overhead. Plunkett/86

.LONG TERM...Sunday through Wednesday...Confidence is increasing
in warm to hot weather Monday through Wednesday as an upper-level
ridge of high pressure builds over the Pacific Northwest. While
ensemble clusters depict small differences in the 500-hPa height
field over the region, roughly 80% of members show a robust ridge
overhead. Forecast HeatRisk peaks at Moderate (level 2 of 4) to
Major (level 3 of 4) for the lower elevations, and would support
some form of heat highlights.

Ensemble NWP is less confident in pattern details Tuesday through
Thursday. While most members show a vorticity maximum diving
southeast from the Gulf of Alaska and developing into a closed
low off the northern California coast Sunday through Monday, its
track as it rides over the ridge and moves onshore sometime
between Tuesday and Wednesday will modulate shower and
thunderstorms chances. Probabilities of showers and thunderstorms
are currently too low (<10%) to have in the forecast. Plunkett/86

.FIRE WEATHER...Locally breezy westerly winds in tandem with low
relative humidity in the Eastern Columbia Gorge, Kittitas Valley,
and portions of the Columbia Basin today are producing some
locally elevated fire weather concerns; while conditions may
locally meet Red Flag criteria, conditions are not expected to be
widespread enough to warrant any Red Flag Warnings.

Tonight through Friday, a weather system will usher in widespread
precipitation chances; a chance of thunderstorms is forecast for
central Oregon and the Blue Mountains. Thunderstorms will be
mostly dry this afternoon and evening, but are expected to be
mostly wet tonight and Friday so no Red Flag Warnings have been
issued. Thunderstorms will be capable of producing strong, gusty
outflow in excess of 50 mph across southeast Deschutes, Crook, and
Grant counties. Plunkett/86

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  58  77  57  87 /   0  30  20   0
ALW  61  77  61  85 /   0  30  20   0
PSC  58  82  59  89 /   0  20  20   0
YKM  57  83  57  88 /   0  20   0   0
HRI  59  80  59  89 /   0  20  20   0
ELN  56  83  56  86 /   0  10   0   0
RDM  50  74  43  82 /  30  40  20   0
LGD  56  74  52  82 /  10  50  20   0
GCD  55  76  48  83 /  30  70  40   0
DLS  60  78  57  85 /  10  20   0   0

&&

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

$$

SHORT TERM...86
LONG TERM....86
AVIATION...82