997
FXUS66 KPDT 210534 CCA
AFDPDT

Area Forecast Discussion...CORRECTED
National Weather Service Pendleton OR
1034 PM PDT Wed Aug 20 2025

.Updated for Aviation

.AVIATION...
06Z TAFS...VFR conditions are expected for the next several days.

Winds will be 10 kts or less through the period, though occasional
gusts to 15 kts can be expected in the afternoon at PDT/RDM/BDN.


&&

.PREV DISCUSSION... /issued 513 PM PDT Wed Aug 20 2025/

AVIATION...00Z TAFs...VFR conditions are forecast for all sites
through the valid period. Breezy winds through the Cascade gaps
are expected to decrease in magnitude this evening. Winds of 10
kts or less are then anticipated at all sites overnight through
Thursday, albeit with periodic afternoon gusts to 15 kts mainly at
PDT/RDM/BDN. Plunkett/86

PREV DISCUSSION... /issued 344 PM PDT Wed Aug 20 2025/

DISCUSSION...Today, quiet weather persists with seasonable high
temperatures across our region with daytime RHs in the 20s and
30s. Locally breezy winds (15-25 mph) may develop over the
Columbia River Gorge and Kittitas Valley this afternoon. Winds
will then start to drop tonight with seasonable min temps. As the
high pressure system starts to build over Thursday, temps will
continue slightly increasing by a few degrees above normal as the
daytime RHs trend downward. Winds will generally remain light to
breezy with gusts under 25 mph. Widespread fire weather concerns
are expected due to RHs and winds not meeting their critical
thresholds.

Friday into next week will be hot and drier as the high pressure
system approaches across our region with the dry airmass. Breezy
winds with low RHs remains overlapping from the Gorge down to
Central OR for Friday. From there, this had elevated our fire
weather concerns that led us to issuing a Fire Weather Watch from
Friday afternoon into the evening. With the ridge axis moving
directly over the forecast area, we may have a potential heatwave
event for Saturday through Tuesday that will increase high temps
to the upper 90s and low 100s. This will also lead to moderate to
major HeatRisk for Saturday, but mainly major for Sunday onwards
across the Columbia Basin area. The Euro and GFS members are in
good agreement with these temps during those days, which boosted
our confidence into issuing an Extreme Heat Watch from Saturday
afternoon through Tuesday evening. Daytime RHs will keep trending
downward into the teens and low 20s with light winds. There is a
slight chance (<20%) of thunderstorms developing over the southern
portion of the eastern mountains Sunday into Wednesday from the
ongoing influence of the monsoonal moisture. Best chances for
development would be at Deschutes County to the Southern Blues
Sunday into Monday. Although these storms could become wet, there
is not enough moisture support hence thus leaving the storms to be
dry with abundant lightning as the potential main threat.
Feaster/97

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  54  89  56  94 /   0   0   0   0
ALW  60  90  61  96 /   0   0   0   0
PSC  54  91  54  96 /   0   0   0   0
YKM  55  89  59  94 /   0   0   0   0
HRI  55  91  56  96 /   0   0   0   0
ELN  51  86  54  93 /   0   0   0   0
RDM  45  90  49  96 /   0   0   0   0
LGD  51  89  53  95 /   0   0   0   0
GCD  51  90  53  98 /   0   0   0   0
DLS  57  93  62  98 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Fire Weather Watch from Friday afternoon through Friday evening
     for ORZ691-703.

     Extreme Heat Watch from Saturday afternoon through Tuesday
     evening for ORZ041-044-507-508-510.

WA...Extreme Heat Watch from Saturday afternoon through Tuesday
     evening for WAZ024-026>029-521-523.

&&

$$

SHORT TERM...97
LONG TERM....97
AVIATION...77