945
FXUS66 KPDT 281120
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
420 AM PDT Tue Jul 28 2026

.KEY MESSAGES...
1. Diurnally driven winds Tuesday

2. Chances of dry thunderstorms Wednesday and Thursday

3. Dry conditions will persist through the week

&&

.DISCUSSION...
Current satellite shows little cloud cover over the region with only
a few cumulus clouds forming in the south and some along the
Cascades. Mostly clear conditions will persist through the rest of
the night with smoke lingering overhead.

Southwest flow aloft will continue through the periods with a
shortwave making its way across the region. This will bring elevated
winds to the region through the day today. The primary areas for
elevated winds will be through the Cascade Gaps, Basin, Gorge and
the Kittitas/Yakima Valleys. Winds are expected to reach to 25-35
mph with NBM showing probabilities between 70-90%. Winds will settle
after Tuesday as the region becomes wedged between the Four Corners
high and the upper level low over the PacNW. Westerly winds will
then take over. Winds will turn to diurnally driven through the
remainder of the week. Even with the elevated winds, the shortwave
will bring cooler temperatures therefore raising the RHs just enough
that fire weather concerns will be elevated but not critical.

Another shortwave will makes its way into the region Wednesday
bringing a bit of instability with it mainly across the southern
portion of the region. Lightning density shows the southern portion
of the region being where the storms are likely to occur with
probabilities in the 10-20% range. These will likely be high based
storms. Looking at forecast soundings, the NAM has MUCAPEs in the
500-700 range with lapse rates of 8-8.3 C/km, LI of -2, bulk shear
of 25 kts and PWATs at only 0.50 inches. These storms will also be
dry in nature.

With the southwest flow turning to west flow, conditions will remain
dry over the region through the week outside of the occasional
thunderstorms. Temperatures will be primarily near normal except for
through the eastern mountains where temperatures will be slightly
above. Temperatures will be in the 80s to low 90s through the week
with confidence in the temperatures between 70-80%.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
VFR conditions to prevail through the period. Low confidence in
consistent smoke impacts at sites, but have put 4SM HZ at PDT
through the overnight hours. Winds will increase to around
12-20kts with gusts 20-30kts across all sites in the afternoon,
with winds expected to settle later in the evening.

&&

.FIRE WEATHER...
Elevated fire weather concerns through the period due to winds.
RHs will increase slightly as and upper level shortwave moves
across the region. The next day for the potential for fire
weather concerns will be Wednesday with the possibility of high
based dry thunderstorms.

&&

.Preliminary Point Temps/PoPs...
PDT  87  54  87  56 /   0   0   0   0
ALW  90  60  89  62 /   0   0   0   0
PSC  92  57  90  58 /   0   0   0   0
YKM  89  56  89  57 /   0   0   0   0
HRI  90  57  90  59 /   0   0   0   0
ELN  81  52  85  54 /   0   0   0   0
RDM  87  48  88  50 /   0   0   0   0
LGD  90  54  91  56 /   0   0   0   0
GCD  92  54  94  55 /   0   0   0   0
DLS  83  59  88  59 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...Air Quality Alert until noon PDT Wednesday for ORZ041-044-049-
     050-502-503-505>511.

&&

$$

DISCUSSION...90
AVIATION...90
FIRE WEATHER...90