310
FXUS66 KPDT 080645
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1145 PM PDT Mon Jul 7 2025

.SHORT TERM...Today through Wednesday...Heat and mountain
thunderstorms will be the main story of the forecast through the
midweek as the PacNW finds itself wedged between a ridge axis to
the north and a cutoff low to the south, currently centered off
the central California coast. This low will gradually lift up
through our forecast area, making for an uptick in winds Tuesday
night into Wednesday, as well as a chance for thunderstorms across
the mountains of central and eastern Oregon, thus making for
elevated fire weather risks.

Today will be quiet, with dry and hot conditions prevailing,
before temps begin their real surge on Tuesday. A Heat Advisory
is in effect on Tuesday for the lower Basin and adjacent valleys,
as temperatures are expected to climb to as high as 105 degrees in
some areas, namely the WA lower Basin. Temps will fall off as
soon as the dry front associated with the upper low moves through
Tuesday evening, but this front will also kick off convective
activity across central Oregon around the same time, gradually
spreading northeastward heading into Wednesday. Have upgraded the
Fire Weather Watch for our central Oregon zones into a Red Flag
Warning as a result, as CAMs continue to consistently pick up on
the thunderstorm threat for the area. Also included OR696 in the
RFW as well, since CAMs seem to be trending storm activity more
and more northeastward. Lack of QPF coverage across guidance
further increases confidence in dry thunderstorms.

Storm activity is not quite as widespread across the eastern
mountains Tuesday night into Wednesday, so held off on any fire
weather products for those zones, especially given the lack of new
fire starts for the area despite the persistent storm activity
there over the last week. Concern instead shifts toward the
Basin, as winds will pick up as mentioned before with the frontal
passage. While RHs will be bone dry on Tuesday, winds don`t really
start to pick up until the evening, leaving Wednesday as the main
potential critical day. RHs increase with this frontal passage,
but models are pretty confident in Wednesday being a blustery day,
with widespread gusts up to and over 30 mph. Have issued a Fire
Weather Watch for both the OR and WA Basin zones as a result.
WA690 in the Kittitas Valley is borderline, but with RHs
forecasted to be in the 30s up there, am less confident about fire
weather headlines for the zone at this time. Evans/74

&&

.LONG TERM...Thursday through Monday...Ensemble guidance
generally points toward a benign pattern after Wednesday. Once the
upper-level low lifts out of the region, ensemble clusters
generally waver between a light NW flow or zonal pattern, which
would yield dry and gradually warming conditions through next
weekend. Winds look to be relatively light outside of the Cascade
Gaps, which are expected to see their usual breeziness, except for
the Kittitas Valley, where a NW flow pattern could perhaps
generate stronger gusts. Sensible weather threats are otherwise
limited under the synoptic pattern ensemble guidance currently
depicts. Evans/74

&&

.AVIATION...06Z TAFs...VFR conditions are forecast for all sites
through the valid period. That said, BDN/RDM have a low chance of
sub-VFR conditions associated with high-based thunderstorms
Tuesday afternoon and evening. Any thunderstorms that develop may
be accompanied by strong, gusty, and erratic outflow winds up to
50 kts in the afternoon and evening, so included mention of TS in
PROB30 groups. Winds will increase Tuesday afternoon and evening
for all sites, especially those nearest the Cascade gaps.
Plunkett/86

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  64 101  65  90 /   0   0  10   0
ALW  69 101  68  91 /   0   0  10   0
PSC  63 103  65  94 /   0   0   0   0
YKM  64 101  63  90 /   0   0   0   0
HRI  64 104  68  93 /   0   0  10   0
ELN  64  97  65  82 /   0   0   0   0
RDM  54  96  52  86 /   0  20  10   0
LGD  61  98  61  88 /   0  20  20   0
GCD  61 100  57  89 /   0  20  20  20
DLS  66  96  66  84 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Fire Weather Watch from Wednesday morning through Wednesday
     evening for ORZ691.

     Heat Advisory from 11 AM to 9 PM PDT Tuesday for ORZ044-507.

     Red Flag Warning from 2 PM to 11 PM PDT Tuesday for ORZ696-700-
     705.

WA...Fire Weather Watch from Wednesday morning through Wednesday
     evening for WAZ691.

     Heat Advisory from 11 AM to 9 PM PDT Tuesday for WAZ027>029.

&&

$$

SHORT TERM...74
LONG TERM....74
AVIATION...86