755
FXUS66 KPDT 300547
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1047 PM PDT Tue Jul 29 2025

Updated Aviation Discussion

.AVIATION...06z TAFs...VFR conditions expected through the period,
except for BDN/RDM, which could see conditions reduced to MVFR or
even IFR late Wednesday afternoon into the evening hours due to
thunderstorm activity. Storms are expected to develop in the area
around 23z and last until just after sunset. Rainfall rates could
briefly drop vsby`s down to sub-VFR levels (confidence 30-40%).
All other sites will see light, terrain-driven winds with mid-
level sct-bkn cigs through the period. Evans/74

&&

.PREV DISCUSSION... /issued 821 PM PDT Tue Jul 29 2025/

EVENING UPDATE...Showers and thunderstorms continue to impact the
southernmost portions of our forecast area this evening, namely in
Grant and Crook Counties. Only real change to the forecast was to
update PoPs coverage and include isolated thunderstorm language.
Thus far, storms have been pulse-like in nature, but have seen a
few strong cells form at times this evening. Showers and storms
are still expected to dissipate overnight, however. Evans/74

PREV DISCUSSION... /issued 229 PM PDT Tue Jul 29 2025/

DISCUSSION...Satellite and radar imagery shows convection activity
moving across the eastern mountains with clear skies for most
locations. Today into tomorrow, S/SW flow aloft continues along the
upper ridge thus keeping chances enhanced for isolated to scattered
thunderstorms during afternoon and evening hours over south-central
OR to the eastern mountains. Chances of wetting rain (CWR) will
remain less than 0.10 inches, leaving with potential chances for
abundant lightning. That said, a Red Flag Warning will continue
through this evening (11PM PDT) for ORZ697-700-705, tomorrow for
WAZ695 to 9PM PDT and tomorrow from 1PM to 11AM Thursday for ORZ700-
704-705. CAMs are showing MUCAPE values of 500-1000 J/Kg, effective
shear at 20-30kts and anomalously high PWATs (>0.70 inches) where
the severity could go from slight to enhanced. Strong outflow winds
could also develop across the aforementioned locations, based on the
wind parameters having inverted-V sounding profiles, DCAPE above
900, and steep lapse rates for dry microburst. The SPC Outlook has
our region in general risk for thunderstorms through Thursday, but
in marginal risk today for the southern part of Grant county.

Thursday is when showers and thunderstorms become widespread over
our region. Chances are 30-50% for these storms may be wet over
the eastern mountains with CWR reaching up to 0.20 inches. However,
these storms will then gradually move more towards the eastern
mountains and portions of the Foothills of the Blues- OR Friday
afternoon before out of our area Friday night. Showers may linger
over the weekend into Monday across the eastern mountains with a
slight chance (<20%) of thunderstorms around Sunday and Monday
afternoon hours. Otherwise, the weather for Tuesday should be
fairly quiet, potentially freeing us from convective activity.

High temperatures will increase to the triple digits tomorrow around
the Columbia Basin, which led us to issue a Heat Advisory for
tomorrow afternoon into evening for ORZ041-508-510, WAZ024-521 and
WAZ695. Temps will begin cooling down slightly Thursday but with the
Lower Basin remaining hot in the triple digits from Wednesday`s, the
Heat Advisory has been issued for Wednesday afternoon to Thursday
evening for WAZ026>029. Otherwise, winds will remain breezy (15-25
mph) into next week with the Gorge and Kittitas Valley being locally
windy conditions. Feaster/97

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  64 100  67  94 /  10   0  20  20
ALW  69 101  72  95 /   0   0  10  20
PSC  62 103  66  99 /   0   0  10  10
YKM  67 101  70  97 /   0   0  10  30
HRI  64 104  69  97 /   0   0  10  20
ELN  64 100  69  95 /   0   0  10  30
RDM  55  95  57  83 /  20  10  40  40
LGD  61  96  64  91 /  10  10  20  30
GCD  59  95  60  90 /  30  20  40  50
DLS  69 102  71  89 /   0   0  10  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory from noon to 11 PM PDT Wednesday for ORZ041-508-
     510.

     Heat Advisory from noon Wednesday to 11 PM PDT Thursday for
     ORZ044-507.

     Red Flag Warning until 11 PM PDT this evening for ORZ697>700-705.

     Red Flag Warning from 1 PM Wednesday to 11 AM PDT Thursday for
     ORZ700-704-705.

WA...Heat Advisory from noon to 11 PM PDT Wednesday for WAZ024-521.

     Heat Advisory from noon Wednesday to 11 PM PDT Thursday for
     WAZ026>029.

     Red Flag Warning from 1 PM to 9 PM PDT Wednesday for WAZ695.

&&

$$

SHORT TERM...74
LONG TERM....97
AVIATION...74