079
FXUS66 KPDT 272319
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
419 PM PDT Mon Jul 27 2026

.KEY MESSAGES...
- Diurnal breezes expected much of this week, with Tuesday and
  Saturday being the windiest days.

- Quiet weather for the upcoming week.

&&

.DISCUSSION...
A 549 dm 500 mb low off the nrn BC coast with an attendant
trough was positioned off the nrn BC coast Today. An attendant
trough will swing eastward out of the NE PAC ocean into the PAC
NW and Interior NW over the next 24 to 48 hours. Southwest flow
aloft will overrun a high pressure at the boundary layer that
will allow for some diurnally driven gap winds, especially
though the Columbia River Gorge however most the the area will
see gusts capped in the 15 to 20 mph range over the next couple
of days. Trends for a compact shortwave riding through the
base of the trough Thursday into early Friday are leading to
some low thunder probabilities across the higher terrain on
Thursday (mostly about a 10% chance or less based on NBM Conus
ensemble members). Heat Risk will remain the Minor category
though most of the period, although by Friday warmer
temperatures in the eastern mountains foothills and north
central Oregon appear to drive the HeatRisk into the Moderate
category, which can affect those sensitive to heat without
cooling or hydration as well as some health systems and
industries. The area of smoke will continue to linger downwind
of ongoing fires from central Oregon across the eastern
mountains. Air Quality Advisories have been issues in accordance
with DEQ alerts though the midday Wednesday as recent AQIs were
int eh 100 to 171 range. By Saturday The upper low and mean
tough over the BC coast is shown to accelerate inland though
Saturday night, flattening (zonal) out and increasing the height
gradient aloft with a frontal passage and significant increase
in westerly surface winds impacting fire risk levels

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
VFR conditions prevail with the exception of PDT experiencing
MVFR due to haze/smoke in the general area. Pinpointing sub-VFR
due to smoke/haze for other TAF sites has proved to be a bit
challenging, but it still in general persist in the area. The
question is if it will get down to the surface and accumulate
enough to drop visibilities. For now, a small chance (5 to 15%)
is dedicated to all sites for temporary reduced visibilities due
to smoke. Otherwise, the other impact will be from the upcoming
cold front that will bring breezy conditions with 20 to 30 knot
gusts throughout the day Tuesday.

&&

.FIRE WEATHER...
Low RH is the critical element relative to fire weather, but
winds will not combine at levels needed to reach a red flag
criteria on anything more than a late afternoon and very spotty
nature This week. A more significant impact to the fire risk
levels will arrive Saturday as a frontal passage increases wind
speeds on a widespread basis.

&&

.Preliminary Point Temps/PoPs...
PDT  57  87  55  87 /   0   0   0   0
ALW  63  90  60  89 /   0   0   0   0
PSC  61  92  57  90 /   0   0   0   0
YKM  59  89  56  89 /   0   0   0   0
HRI  61  90  58  90 /   0   0   0   0
ELN  56  81  52  84 /   0   0   0   0
RDM  50  87  49  88 /   0   0   0   0
LGD  56  89  55  90 /   0   0   0   0
GCD  54  92  54  93 /   0   0   0   0
DLS  62  84  59  87 /   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...71
AVIATION...95
FIRE WEATHER...71